fs/btrfs/inode.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/bio.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/file.h>
  23 #include <linux/fs.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/highmem.h>
  26 #include <linux/time.h>
  27 #include <linux/init.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mpage.h>
  31 #include <linux/swap.h>
  32 #include <linux/writeback.h>
  33 #include <linux/statfs.h>
  34 #include <linux/compat.h>
  35 #include <linux/bit_spinlock.h>
  36 #include <linux/xattr.h>
  37 #include <linux/posix_acl.h>
  38 #include <linux/falloc.h>
  39 #include <linux/slab.h>
  40 #include <linux/ratelimit.h>
  41 #include <linux/mount.h>
  42 #include <linux/btrfs.h>
  43 #include <linux/blkdev.h>
  44 #include <linux/posix_acl_xattr.h>
  45 #include <linux/uio.h>
  46 #include "ctree.h"
  47 #include "disk-io.h"
  48 #include "transaction.h"
  49 #include "btrfs_inode.h"
  50 #include "print-tree.h"
  51 #include "ordered-data.h"
  52 #include "xattr.h"
  53 #include "tree-log.h"
  54 #include "volumes.h"
  55 #include "compression.h"
  56 #include "locking.h"
  57 #include "free-space-cache.h"
  58 #include "inode-map.h"
  59 #include "backref.h"
  60 #include "hash.h"
  61 #include "props.h"
  62 #include "qgroup.h"
  63
  64 struct btrfs_iget_args {
  65         struct btrfs_key *location;
  66         struct btrfs_root *root;
  67 };
  68
  69 struct btrfs_dio_data {
  70         u64 outstanding_extents;
  71         u64 reserve;
  72         u64 unsubmitted_oe_range_start;
  73         u64 unsubmitted_oe_range_end;
  74 };
  75
  76 static const struct inode_operations btrfs_dir_inode_operations;
  77 static const struct inode_operations btrfs_symlink_inode_operations;
  78 static const struct inode_operations btrfs_dir_ro_inode_operations;
  79 static const struct inode_operations btrfs_special_inode_operations;
  80 static const struct inode_operations btrfs_file_inode_operations;
  81 static const struct address_space_operations btrfs_aops;
  82 static const struct address_space_operations btrfs_symlink_aops;
  83 static const struct file_operations btrfs_dir_file_operations;
  84 static const struct extent_io_ops btrfs_extent_io_ops;
  85
  86 static struct kmem_cache *btrfs_inode_cachep;
  87 struct kmem_cache *btrfs_trans_handle_cachep;
  88 struct kmem_cache *btrfs_transaction_cachep;
  89 struct kmem_cache *btrfs_path_cachep;
  90 struct kmem_cache *btrfs_free_space_cachep;
  91
  92 #define S_SHIFT 12
  93 static const unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  94         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  95         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  96         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  97         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  98         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  99         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
 100         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
 101 };
 102
 103 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
 104 static int btrfs_truncate(struct inode *inode);
 105 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
 106 static noinline int cow_file_range(struct inode *inode,
 107                                    struct page *locked_page,
 108                                    u64 start, u64 end, int *page_started,
 109                                    unsigned long *nr_written, int unlock);
 110 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
 111                                            u64 len, u64 orig_start,
 112                                            u64 block_start, u64 block_len,
 113                                            u64 orig_block_len, u64 ram_bytes,
 114                                            int type);
 115
 116 static int btrfs_dirty_inode(struct inode *inode);
 117
 118 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 119 void btrfs_test_inode_set_ops(struct inode *inode)
 120 {
 121         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
 122 }
 123 #endif
 124
 125 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 126                                      struct inode *inode,  struct inode *dir,
 127                                      const struct qstr *qstr)
 128 {
 129         int err;
 130
 131         err = btrfs_init_acl(trans, inode, dir);
 132         if (!err)
 133                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 134         return err;
 135 }
 136
 137 /*
 138  * this does all the hard work for inserting an inline extent into
 139  * the btree.  The caller should have done a btrfs_drop_extents so that
 140  * no overlapping inline items exist in the btree
 141  */
 142 static int insert_inline_extent(struct btrfs_trans_handle *trans,
 143                                 struct btrfs_path *path, int extent_inserted,
 144                                 struct btrfs_root *root, struct inode *inode,
 145                                 u64 start, size_t size, size_t compressed_size,
 146                                 int compress_type,
 147                                 struct page **compressed_pages)
 148 {
 149         struct extent_buffer *leaf;
 150         struct page *page = NULL;
 151         char *kaddr;
 152         unsigned long ptr;
 153         struct btrfs_file_extent_item *ei;
 154         int err = 0;
 155         int ret;
 156         size_t cur_size = size;
 157         unsigned long offset;
 158
 159         if (compressed_size && compressed_pages)
 160                 cur_size = compressed_size;
 161
 162         inode_add_bytes(inode, size);
 163
 164         if (!extent_inserted) {
 165                 struct btrfs_key key;
 166                 size_t datasize;
 167
 168                 key.objectid = btrfs_ino(inode);
 169                 key.offset = start;
 170                 key.type = BTRFS_EXTENT_DATA_KEY;
 171
 172                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 173                 path->leave_spinning = 1;
 174                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 175                                               datasize);
 176                 if (ret) {
 177                         err = ret;
 178                         goto fail;
 179                 }
 180         }
 181         leaf = path->nodes[0];
 182         ei = btrfs_item_ptr(leaf, path->slots[0],
 183                             struct btrfs_file_extent_item);
 184         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 185         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 186         btrfs_set_file_extent_encryption(leaf, ei, 0);
 187         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 188         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 189         ptr = btrfs_file_extent_inline_start(ei);
 190
 191         if (compress_type != BTRFS_COMPRESS_NONE) {
 192                 struct page *cpage;
 193                 int i = 0;
 194                 while (compressed_size > 0) {
 195                         cpage = compressed_pages[i];
 196                         cur_size = min_t(unsigned long, compressed_size,
 197                                        PAGE_SIZE);
 198
 199                         kaddr = kmap_atomic(cpage);
 200                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 201                         kunmap_atomic(kaddr);
 202
 203                         i++;
 204                         ptr += cur_size;
 205                         compressed_size -= cur_size;
 206                 }
 207                 btrfs_set_file_extent_compression(leaf, ei,
 208                                                   compress_type);
 209         } else {
 210                 page = find_get_page(inode->i_mapping,
 211                                      start >> PAGE_SHIFT);
 212                 btrfs_set_file_extent_compression(leaf, ei, 0);
 213                 kaddr = kmap_atomic(page);
 214                 offset = start & (PAGE_SIZE - 1);
 215                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 216                 kunmap_atomic(kaddr);
 217                 put_page(page);
 218         }
 219         btrfs_mark_buffer_dirty(leaf);
 220         btrfs_release_path(path);
 221
 222         /*
 223          * we're an inline extent, so nobody can
 224          * extend the file past i_size without locking
 225          * a page we already have locked.
 226          *
 227          * We must do any isize and inode updates
 228          * before we unlock the pages.  Otherwise we
 229          * could end up racing with unlink.
 230          */
 231         BTRFS_I(inode)->disk_i_size = inode->i_size;
 232         ret = btrfs_update_inode(trans, root, inode);
 233
 234         return ret;
 235 fail:
 236         return err;
 237 }
 238
 239
 240 /*
 241  * conditionally insert an inline extent into the file.  This
 242  * does the checks required to make sure the data is small enough
 243  * to fit as an inline extent.
 244  */
 245 static noinline int cow_file_range_inline(struct btrfs_root *root,
 246                                           struct inode *inode, u64 start,
 247                                           u64 end, size_t compressed_size,
 248                                           int compress_type,
 249                                           struct page **compressed_pages)
 250 {
 251         struct btrfs_trans_handle *trans;
 252         u64 isize = i_size_read(inode);
 253         u64 actual_end = min(end + 1, isize);
 254         u64 inline_len = actual_end - start;
 255         u64 aligned_end = ALIGN(end, root->sectorsize);
 256         u64 data_len = inline_len;
 257         int ret;
 258         struct btrfs_path *path;
 259         int extent_inserted = 0;
 260         u32 extent_item_size;
 261
 262         if (compressed_size)
 263                 data_len = compressed_size;
 264
 265         if (start > 0 ||
 266             actual_end > root->sectorsize ||
 267             data_len > BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 268             (!compressed_size &&
 269             (actual_end & (root->sectorsize - 1)) == 0) ||
 270             end + 1 < isize ||
 271             data_len > root->fs_info->max_inline) {
 272                 return 1;
 273         }
 274
 275         path = btrfs_alloc_path();
 276         if (!path)
 277                 return -ENOMEM;
 278
 279         trans = btrfs_join_transaction(root);
 280         if (IS_ERR(trans)) {
 281                 btrfs_free_path(path);
 282                 return PTR_ERR(trans);
 283         }
 284         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 285
 286         if (compressed_size && compressed_pages)
 287                 extent_item_size = btrfs_file_extent_calc_inline_size(
 288                    compressed_size);
 289         else
 290                 extent_item_size = btrfs_file_extent_calc_inline_size(
 291                     inline_len);
 292
 293         ret = __btrfs_drop_extents(trans, root, inode, path,
 294                                    start, aligned_end, NULL,
 295                                    1, 1, extent_item_size, &extent_inserted);
 296         if (ret) {
 297                 btrfs_abort_transaction(trans, root, ret);
 298                 goto out;
 299         }
 300
 301         if (isize > actual_end)
 302                 inline_len = min_t(u64, isize, actual_end);
 303         ret = insert_inline_extent(trans, path, extent_inserted,
 304                                    root, inode, start,
 305                                    inline_len, compressed_size,
 306                                    compress_type, compressed_pages);
 307         if (ret && ret != -ENOSPC) {
 308                 btrfs_abort_transaction(trans, root, ret);
 309                 goto out;
 310         } else if (ret == -ENOSPC) {
 311                 ret = 1;
 312                 goto out;
 313         }
 314
 315         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 316         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 317         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 318 out:
 319         /*
 320          * Don't forget to free the reserved space, as for inlined extent
 321          * it won't count as data extent, free them directly here.
 322          * And at reserve time, it's always aligned to page size, so
 323          * just free one page here.
 324          */
 325         btrfs_qgroup_free_data(inode, 0, PAGE_SIZE);
 326         btrfs_free_path(path);
 327         btrfs_end_transaction(trans, root);
 328         return ret;
 329 }
 330
 331 struct async_extent {
 332         u64 start;
 333         u64 ram_size;
 334         u64 compressed_size;
 335         struct page **pages;
 336         unsigned long nr_pages;
 337         int compress_type;
 338         struct list_head list;
 339 };
 340
 341 struct async_cow {
 342         struct inode *inode;
 343         struct btrfs_root *root;
 344         struct page *locked_page;
 345         u64 start;
 346         u64 end;
 347         struct list_head extents;
 348         struct btrfs_work work;
 349 };
 350
 351 static noinline int add_async_extent(struct async_cow *cow,
 352                                      u64 start, u64 ram_size,
 353                                      u64 compressed_size,
 354                                      struct page **pages,
 355                                      unsigned long nr_pages,
 356                                      int compress_type)
 357 {
 358         struct async_extent *async_extent;
 359
 360         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 361         BUG_ON(!async_extent); /* -ENOMEM */
 362         async_extent->start = start;
 363         async_extent->ram_size = ram_size;
 364         async_extent->compressed_size = compressed_size;
 365         async_extent->pages = pages;
 366         async_extent->nr_pages = nr_pages;
 367         async_extent->compress_type = compress_type;
 368         list_add_tail(&async_extent->list, &cow->extents);
 369         return 0;
 370 }
 371
 372 static inline int inode_need_compress(struct inode *inode)
 373 {
 374         struct btrfs_root *root = BTRFS_I(inode)->root;
 375
 376         /* force compress */
 377         if (btrfs_test_opt(root, FORCE_COMPRESS))
 378                 return 1;
 379         /* bad compression ratios */
 380         if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 381                 return 0;
 382         if (btrfs_test_opt(root, COMPRESS) ||
 383             BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS ||
 384             BTRFS_I(inode)->force_compress)
 385                 return 1;
 386         return 0;
 387 }
 388
 389 /*
 390  * we create compressed extents in two phases.  The first
 391  * phase compresses a range of pages that have already been
 392  * locked (both pages and state bits are locked).
 393  *
 394  * This is done inside an ordered work queue, and the compression
 395  * is spread across many cpus.  The actual IO submission is step
 396  * two, and the ordered work queue takes care of making sure that
 397  * happens in the same order things were put onto the queue by
 398  * writepages and friends.
 399  *
 400  * If this code finds it can't get good compression, it puts an
 401  * entry onto the work queue to write the uncompressed bytes.  This
 402  * makes sure that both compressed inodes and uncompressed inodes
 403  * are written in the same order that the flusher thread sent them
 404  * down.
 405  */
 406 static noinline void compress_file_range(struct inode *inode,
 407                                         struct page *locked_page,
 408                                         u64 start, u64 end,
 409                                         struct async_cow *async_cow,
 410                                         int *num_added)
 411 {
 412         struct btrfs_root *root = BTRFS_I(inode)->root;
 413         u64 num_bytes;
 414         u64 blocksize = root->sectorsize;
 415         u64 actual_end;
 416         u64 isize = i_size_read(inode);
 417         int ret = 0;
 418         struct page **pages = NULL;
 419         unsigned long nr_pages;
 420         unsigned long nr_pages_ret = 0;
 421         unsigned long total_compressed = 0;
 422         unsigned long total_in = 0;
 423         unsigned long max_compressed = SZ_128K;
 424         unsigned long max_uncompressed = SZ_128K;
 425         int i;
 426         int will_compress;
 427         int compress_type = root->fs_info->compress_type;
 428         int redirty = 0;
 429
 430         /* if this is a small write inside eof, kick off a defrag */
 431         if ((end - start + 1) < SZ_16K &&
 432             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 433                 btrfs_add_inode_defrag(NULL, inode);
 434
 435         actual_end = min_t(u64, isize, end + 1);
 436 again:
 437         will_compress = 0;
 438         nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
 439         nr_pages = min_t(unsigned long, nr_pages, SZ_128K / PAGE_SIZE);
 440
 441         /*
 442          * we don't want to send crud past the end of i_size through
 443          * compression, that's just a waste of CPU time.  So, if the
 444          * end of the file is before the start of our current
 445          * requested range of bytes, we bail out to the uncompressed
 446          * cleanup code that can deal with all of this.
 447          *
 448          * It isn't really the fastest way to fix things, but this is a
 449          * very uncommon corner.
 450          */
 451         if (actual_end <= start)
 452                 goto cleanup_and_bail_uncompressed;
 453
 454         total_compressed = actual_end - start;
 455
 456         /*
 457          * skip compression for a small file range(<=blocksize) that
 458          * isn't an inline extent, since it doesn't save disk space at all.
 459          */
 460         if (total_compressed <= blocksize &&
 461            (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 462                 goto cleanup_and_bail_uncompressed;
 463
 464         /* we want to make sure that amount of ram required to uncompress
 465          * an extent is reasonable, so we limit the total size in ram
 466          * of a compressed extent to 128k.  This is a crucial number
 467          * because it also controls how easily we can spread reads across
 468          * cpus for decompression.
 469          *
 470          * We also want to make sure the amount of IO required to do
 471          * a random read is reasonably small, so we limit the size of
 472          * a compressed extent to 128k.
 473          */
 474         total_compressed = min(total_compressed, max_uncompressed);
 475         num_bytes = ALIGN(end - start + 1, blocksize);
 476         num_bytes = max(blocksize,  num_bytes);
 477         total_in = 0;
 478         ret = 0;
 479
 480         /*
 481          * we do compression for mount -o compress and when the
 482          * inode has not been flagged as nocompress.  This flag can
 483          * change at any time if we discover bad compression ratios.
 484          */
 485         if (inode_need_compress(inode)) {
 486                 WARN_ON(pages);
 487                 pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
 488                 if (!pages) {
 489                         /* just bail out to the uncompressed code */
 490                         goto cont;
 491                 }
 492
 493                 if (BTRFS_I(inode)->force_compress)
 494                         compress_type = BTRFS_I(inode)->force_compress;
 495
 496                 /*
 497                  * we need to call clear_page_dirty_for_io on each
 498                  * page in the range.  Otherwise applications with the file
 499                  * mmap'd can wander in and change the page contents while
 500                  * we are compressing them.
 501                  *
 502                  * If the compression fails for any reason, we set the pages
 503                  * dirty again later on.
 504                  */
 505                 extent_range_clear_dirty_for_io(inode, start, end);
 506                 redirty = 1;
 507                 ret = btrfs_compress_pages(compress_type,
 508                                            inode->i_mapping, start,
 509                                            total_compressed, pages,
 510                                            nr_pages, &nr_pages_ret,
 511                                            &total_in,
 512                                            &total_compressed,
 513                                            max_compressed);
 514
 515                 if (!ret) {
 516                         unsigned long offset = total_compressed &
 517                                 (PAGE_SIZE - 1);
 518                         struct page *page = pages[nr_pages_ret - 1];
 519                         char *kaddr;
 520
 521                         /* zero the tail end of the last page, we might be
 522                          * sending it down to disk
 523                          */
 524                         if (offset) {
 525                                 kaddr = kmap_atomic(page);
 526                                 memset(kaddr + offset, 0,
 527                                        PAGE_SIZE - offset);
 528                                 kunmap_atomic(kaddr);
 529                         }
 530                         will_compress = 1;
 531                 }
 532         }
 533 cont:
 534         if (start == 0) {
 535                 /* lets try to make an inline extent */
 536                 if (ret || total_in < (actual_end - start)) {
 537                         /* we didn't compress the entire range, try
 538                          * to make an uncompressed inline extent.
 539                          */
 540                         ret = cow_file_range_inline(root, inode, start, end,
 541                                                     0, 0, NULL);
 542                 } else {
 543                         /* try making a compressed inline extent */
 544                         ret = cow_file_range_inline(root, inode, start, end,
 545                                                     total_compressed,
 546                                                     compress_type, pages);
 547                 }
 548                 if (ret <= 0) {
 549                         unsigned long clear_flags = EXTENT_DELALLOC |
 550                                 EXTENT_DEFRAG;
 551                         unsigned long page_error_op;
 552
 553                         clear_flags |= (ret < 0) ? EXTENT_DO_ACCOUNTING : 0;
 554                         page_error_op = ret < 0 ? PAGE_SET_ERROR : 0;
 555
 556                         /*
 557                          * inline extent creation worked or returned error,
 558                          * we don't need to create any more async work items.
 559                          * Unlock and free up our temp pages.
 560                          */
 561                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 562                                                      clear_flags, PAGE_UNLOCK |
 563                                                      PAGE_CLEAR_DIRTY |
 564                                                      PAGE_SET_WRITEBACK |
 565                                                      page_error_op |
 566                                                      PAGE_END_WRITEBACK);
 567                         goto free_pages_out;
 568                 }
 569         }
 570
 571         if (will_compress) {
 572                 /*
 573                  * we aren't doing an inline extent round the compressed size
 574                  * up to a block size boundary so the allocator does sane
 575                  * things
 576                  */
 577                 total_compressed = ALIGN(total_compressed, blocksize);
 578
 579                 /*
 580                  * one last check to make sure the compression is really a
 581                  * win, compare the page count read with the blocks on disk
 582                  */
 583                 total_in = ALIGN(total_in, PAGE_SIZE);
 584                 if (total_compressed >= total_in) {
 585                         will_compress = 0;
 586                 } else {
 587                         num_bytes = total_in;
 588                 }
 589         }
 590         if (!will_compress && pages) {
 591                 /*
 592                  * the compression code ran but failed to make things smaller,
 593                  * free any pages it allocated and our page pointer array
 594                  */
 595                 for (i = 0; i < nr_pages_ret; i++) {
 596                         WARN_ON(pages[i]->mapping);
 597                         put_page(pages[i]);
 598                 }
 599                 kfree(pages);
 600                 pages = NULL;
 601                 total_compressed = 0;
 602                 nr_pages_ret = 0;
 603
 604                 /* flag the file so we don't compress in the future */
 605                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
 606                     !(BTRFS_I(inode)->force_compress)) {
 607                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 608                 }
 609         }
 610         if (will_compress) {
 611                 *num_added += 1;
 612
 613                 /* the async work queues will take care of doing actual
 614                  * allocation on disk for these compressed pages,
 615                  * and will submit them to the elevator.
 616                  */
 617                 add_async_extent(async_cow, start, num_bytes,
 618                                  total_compressed, pages, nr_pages_ret,
 619                                  compress_type);
 620
 621                 if (start + num_bytes < end) {
 622                         start += num_bytes;
 623                         pages = NULL;
 624                         cond_resched();
 625                         goto again;
 626                 }
 627         } else {
 628 cleanup_and_bail_uncompressed:
 629                 /*
 630                  * No compression, but we still need to write the pages in
 631                  * the file we've been given so far.  redirty the locked
 632                  * page if it corresponds to our extent and set things up
 633                  * for the async work queue to run cow_file_range to do
 634                  * the normal delalloc dance
 635                  */
 636                 if (page_offset(locked_page) >= start &&
 637                     page_offset(locked_page) <= end) {
 638                         __set_page_dirty_nobuffers(locked_page);
 639                         /* unlocked later on in the async handlers */
 640                 }
 641                 if (redirty)
 642                         extent_range_redirty_for_io(inode, start, end);
 643                 add_async_extent(async_cow, start, end - start + 1,
 644                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
 645                 *num_added += 1;
 646         }
 647
 648         return;
 649
 650 free_pages_out:
 651         for (i = 0; i < nr_pages_ret; i++) {
 652                 WARN_ON(pages[i]->mapping);
 653                 put_page(pages[i]);
 654         }
 655         kfree(pages);
 656 }
 657
 658 static void free_async_extent_pages(struct async_extent *async_extent)
 659 {
 660         int i;
 661
 662         if (!async_extent->pages)
 663                 return;
 664
 665         for (i = 0; i < async_extent->nr_pages; i++) {
 666                 WARN_ON(async_extent->pages[i]->mapping);
 667                 put_page(async_extent->pages[i]);
 668         }
 669         kfree(async_extent->pages);
 670         async_extent->nr_pages = 0;
 671         async_extent->pages = NULL;
 672 }
 673
 674 /*
 675  * phase two of compressed writeback.  This is the ordered portion
 676  * of the code, which only gets called in the order the work was
 677  * queued.  We walk all the async extents created by compress_file_range
 678  * and send them down to the disk.
 679  */
 680 static noinline void submit_compressed_extents(struct inode *inode,
 681                                               struct async_cow *async_cow)
 682 {
 683         struct async_extent *async_extent;
 684         u64 alloc_hint = 0;
 685         struct btrfs_key ins;
 686         struct extent_map *em;
 687         struct btrfs_root *root = BTRFS_I(inode)->root;
 688         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 689         struct extent_io_tree *io_tree;
 690         int ret = 0;
 691
 692 again:
 693         while (!list_empty(&async_cow->extents)) {
 694                 async_extent = list_entry(async_cow->extents.next,
 695                                           struct async_extent, list);
 696                 list_del(&async_extent->list);
 697
 698                 io_tree = &BTRFS_I(inode)->io_tree;
 699
 700 retry:
 701                 /* did the compression code fall back to uncompressed IO? */
 702                 if (!async_extent->pages) {
 703                         int page_started = 0;
 704                         unsigned long nr_written = 0;
 705
 706                         lock_extent(io_tree, async_extent->start,
 707                                          async_extent->start +
 708                                          async_extent->ram_size - 1);
 709
 710                         /* allocate blocks */
 711                         ret = cow_file_range(inode, async_cow->locked_page,
 712                                              async_extent->start,
 713                                              async_extent->start +
 714                                              async_extent->ram_size - 1,
 715                                              &page_started, &nr_written, 0);
 716
 717                         /* JDM XXX */
 718
 719                         /*
 720                          * if page_started, cow_file_range inserted an
 721                          * inline extent and took care of all the unlocking
 722                          * and IO for us.  Otherwise, we need to submit
 723                          * all those pages down to the drive.
 724                          */
 725                         if (!page_started && !ret)
 726                                 extent_write_locked_range(io_tree,
 727                                                   inode, async_extent->start,
 728                                                   async_extent->start +
 729                                                   async_extent->ram_size - 1,
 730                                                   btrfs_get_extent,
 731                                                   WB_SYNC_ALL);
 732                         else if (ret)
 733                                 unlock_page(async_cow->locked_page);
 734                         kfree(async_extent);
 735                         cond_resched();
 736                         continue;
 737                 }
 738
 739                 lock_extent(io_tree, async_extent->start,
 740                             async_extent->start + async_extent->ram_size - 1);
 741
 742                 ret = btrfs_reserve_extent(root,
 743                                            async_extent->compressed_size,
 744                                            async_extent->compressed_size,
 745                                            0, alloc_hint, &ins, 1, 1);
 746                 if (ret) {
 747                         free_async_extent_pages(async_extent);
 748
 749                         if (ret == -ENOSPC) {
 750                                 unlock_extent(io_tree, async_extent->start,
 751                                               async_extent->start +
 752                                               async_extent->ram_size - 1);
 753
 754                                 /*
 755                                  * we need to redirty the pages if we decide to
 756                                  * fallback to uncompressed IO, otherwise we
 757                                  * will not submit these pages down to lower
 758                                  * layers.
 759                                  */
 760                                 extent_range_redirty_for_io(inode,
 761                                                 async_extent->start,
 762                                                 async_extent->start +
 763                                                 async_extent->ram_size - 1);
 764
 765                                 goto retry;
 766                         }
 767                         goto out_free;
 768                 }
 769                 /*
 770                  * here we're doing allocation and writeback of the
 771                  * compressed pages
 772                  */
 773                 btrfs_drop_extent_cache(inode, async_extent->start,
 774                                         async_extent->start +
 775                                         async_extent->ram_size - 1, 0);
 776
 777                 em = alloc_extent_map();
 778                 if (!em) {
 779                         ret = -ENOMEM;
 780                         goto out_free_reserve;
 781                 }
 782                 em->start = async_extent->start;
 783                 em->len = async_extent->ram_size;
 784                 em->orig_start = em->start;
 785                 em->mod_start = em->start;
 786                 em->mod_len = em->len;
 787
 788                 em->block_start = ins.objectid;
 789                 em->block_len = ins.offset;
 790                 em->orig_block_len = ins.offset;
 791                 em->ram_bytes = async_extent->ram_size;
 792                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 793                 em->compress_type = async_extent->compress_type;
 794                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 795                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 796                 em->generation = -1;
 797
 798                 while (1) {
 799                         write_lock(&em_tree->lock);
 800                         ret = add_extent_mapping(em_tree, em, 1);
 801                         write_unlock(&em_tree->lock);
 802                         if (ret != -EEXIST) {
 803                                 free_extent_map(em);
 804                                 break;
 805                         }
 806                         btrfs_drop_extent_cache(inode, async_extent->start,
 807                                                 async_extent->start +
 808                                                 async_extent->ram_size - 1, 0);
 809                 }
 810
 811                 if (ret)
 812                         goto out_free_reserve;
 813
 814                 ret = btrfs_add_ordered_extent_compress(inode,
 815                                                 async_extent->start,
 816                                                 ins.objectid,
 817                                                 async_extent->ram_size,
 818                                                 ins.offset,
 819                                                 BTRFS_ORDERED_COMPRESSED,
 820                                                 async_extent->compress_type);
 821                 if (ret) {
 822                         btrfs_drop_extent_cache(inode, async_extent->start,
 823                                                 async_extent->start +
 824                                                 async_extent->ram_size - 1, 0);
 825                         goto out_free_reserve;
 826                 }
 827                 btrfs_dec_block_group_reservations(root->fs_info, ins.objectid);
 828
 829                 /*
 830                  * clear dirty, set writeback and unlock the pages.
 831                  */
 832                 extent_clear_unlock_delalloc(inode, async_extent->start,
 833                                 async_extent->start +
 834                                 async_extent->ram_size - 1,
 835                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 836                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 837                                 PAGE_SET_WRITEBACK);
 838                 ret = btrfs_submit_compressed_write(inode,
 839                                     async_extent->start,
 840                                     async_extent->ram_size,
 841                                     ins.objectid,
 842                                     ins.offset, async_extent->pages,
 843                                     async_extent->nr_pages);
 844                 if (ret) {
 845                         struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 846                         struct page *p = async_extent->pages[0];
 847                         const u64 start = async_extent->start;
 848                         const u64 end = start + async_extent->ram_size - 1;
 849
 850                         p->mapping = inode->i_mapping;
 851                         tree->ops->writepage_end_io_hook(p, start, end,
 852                                                          NULL, 0);
 853                         p->mapping = NULL;
 854                         extent_clear_unlock_delalloc(inode, start, end, NULL, 0,
 855                                                      PAGE_END_WRITEBACK |
 856                                                      PAGE_SET_ERROR);
 857                         free_async_extent_pages(async_extent);
 858                 }
 859                 alloc_hint = ins.objectid + ins.offset;
 860                 kfree(async_extent);
 861                 cond_resched();
 862         }
 863         return;
 864 out_free_reserve:
 865         btrfs_dec_block_group_reservations(root->fs_info, ins.objectid);
 866         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
 867 out_free:
 868         extent_clear_unlock_delalloc(inode, async_extent->start,
 869                                      async_extent->start +
 870                                      async_extent->ram_size - 1,
 871                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 872                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 873                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 874                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK |
 875                                      PAGE_SET_ERROR);
 876         free_async_extent_pages(async_extent);
 877         kfree(async_extent);
 878         goto again;
 879 }
 880
 881 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 882                                       u64 num_bytes)
 883 {
 884         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 885         struct extent_map *em;
 886         u64 alloc_hint = 0;
 887
 888         read_lock(&em_tree->lock);
 889         em = search_extent_mapping(em_tree, start, num_bytes);
 890         if (em) {
 891                 /*
 892                  * if block start isn't an actual block number then find the
 893                  * first block in this inode and use that as a hint.  If that
 894                  * block is also bogus then just don't worry about it.
 895                  */
 896                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 897                         free_extent_map(em);
 898                         em = search_extent_mapping(em_tree, 0, 0);
 899                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 900                                 alloc_hint = em->block_start;
 901                         if (em)
 902                                 free_extent_map(em);
 903                 } else {
 904                         alloc_hint = em->block_start;
 905                         free_extent_map(em);
 906                 }
 907         }
 908         read_unlock(&em_tree->lock);
 909
 910         return alloc_hint;
 911 }
 912
 913 /*
 914  * when extent_io.c finds a delayed allocation range in the file,
 915  * the call backs end up in this code.  The basic idea is to
 916  * allocate extents on disk for the range, and create ordered data structs
 917  * in ram to track those extents.
 918  *
 919  * locked_page is the page that writepage had locked already.  We use
 920  * it to make sure we don't do extra locks or unlocks.
 921  *
 922  * *page_started is set to one if we unlock locked_page and do everything
 923  * required to start IO on it.  It may be clean and already done with
 924  * IO when we return.
 925  */
 926 static noinline int cow_file_range(struct inode *inode,
 927                                    struct page *locked_page,
 928                                    u64 start, u64 end, int *page_started,
 929                                    unsigned long *nr_written,
 930                                    int unlock)
 931 {
 932         struct btrfs_root *root = BTRFS_I(inode)->root;
 933         u64 alloc_hint = 0;
 934         u64 num_bytes;
 935         unsigned long ram_size;
 936         u64 disk_num_bytes;
 937         u64 cur_alloc_size;
 938         u64 blocksize = root->sectorsize;
 939         struct btrfs_key ins;
 940         struct extent_map *em;
 941         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 942         int ret = 0;
 943
 944         if (btrfs_is_free_space_inode(inode)) {
 945                 WARN_ON_ONCE(1);
 946                 ret = -EINVAL;
 947                 goto out_unlock;
 948         }
 949
 950         num_bytes = ALIGN(end - start + 1, blocksize);
 951         num_bytes = max(blocksize,  num_bytes);
 952         disk_num_bytes = num_bytes;
 953
 954         /* if this is a small write inside eof, kick off defrag */
 955         if (num_bytes < SZ_64K &&
 956             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 957                 btrfs_add_inode_defrag(NULL, inode);
 958
 959         if (start == 0) {
 960                 /* lets try to make an inline extent */
 961                 ret = cow_file_range_inline(root, inode, start, end, 0, 0,
 962                                             NULL);
 963                 if (ret == 0) {
 964                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 965                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 966                                      EXTENT_DEFRAG, PAGE_UNLOCK |
 967                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 968                                      PAGE_END_WRITEBACK);
 969
 970                         *nr_written = *nr_written +
 971                              (end - start + PAGE_SIZE) / PAGE_SIZE;
 972                         *page_started = 1;
 973                         goto out;
 974                 } else if (ret < 0) {
 975                         goto out_unlock;
 976                 }
 977         }
 978
 979         BUG_ON(disk_num_bytes >
 980                btrfs_super_total_bytes(root->fs_info->super_copy));
 981
 982         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 983         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 984
 985         while (disk_num_bytes > 0) {
 986                 unsigned long op;
 987
 988                 cur_alloc_size = disk_num_bytes;
 989                 ret = btrfs_reserve_extent(root, cur_alloc_size,
 990                                            root->sectorsize, 0, alloc_hint,
 991                                            &ins, 1, 1);
 992                 if (ret < 0)
 993                         goto out_unlock;
 994
 995                 em = alloc_extent_map();
 996                 if (!em) {
 997                         ret = -ENOMEM;
 998                         goto out_reserve;
 999                 }
1000                 em->start = start;
1001                 em->orig_start = em->start;
1002                 ram_size = ins.offset;
1003                 em->len = ins.offset;
1004                 em->mod_start = em->start;
1005                 em->mod_len = em->len;
1006
1007                 em->block_start = ins.objectid;
1008                 em->block_len = ins.offset;
1009                 em->orig_block_len = ins.offset;
1010                 em->ram_bytes = ram_size;
1011                 em->bdev = root->fs_info->fs_devices->latest_bdev;
1012                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
1013                 em->generation = -1;
1014
1015                 while (1) {
1016                         write_lock(&em_tree->lock);
1017                         ret = add_extent_mapping(em_tree, em, 1);
1018                         write_unlock(&em_tree->lock);
1019                         if (ret != -EEXIST) {
1020                                 free_extent_map(em);
1021                                 break;
1022                         }
1023                         btrfs_drop_extent_cache(inode, start,
1024                                                 start + ram_size - 1, 0);
1025                 }
1026                 if (ret)
1027                         goto out_reserve;
1028
1029                 cur_alloc_size = ins.offset;
1030                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
1031                                                ram_size, cur_alloc_size, 0);
1032                 if (ret)
1033                         goto out_drop_extent_cache;
1034
1035                 if (root->root_key.objectid ==
1036                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1037                         ret = btrfs_reloc_clone_csums(inode, start,
1038                                                       cur_alloc_size);
1039                         if (ret)
1040                                 goto out_drop_extent_cache;
1041                 }
1042
1043                 btrfs_dec_block_group_reservations(root->fs_info, ins.objectid);
1044
1045                 if (disk_num_bytes < cur_alloc_size)
1046                         break;
1047
1048                 /* we're not doing compressed IO, don't unlock the first
1049                  * page (which the caller expects to stay locked), don't
1050                  * clear any dirty bits and don't set any writeback bits
1051                  *
1052                  * Do set the Private2 bit so we know this page was properly
1053                  * setup for writepage
1054                  */
1055                 op = unlock ? PAGE_UNLOCK : 0;
1056                 op |= PAGE_SET_PRIVATE2;
1057
1058                 extent_clear_unlock_delalloc(inode, start,
1059                                              start + ram_size - 1, locked_page,
1060                                              EXTENT_LOCKED | EXTENT_DELALLOC,
1061                                              op);
1062                 disk_num_bytes -= cur_alloc_size;
1063                 num_bytes -= cur_alloc_size;
1064                 alloc_hint = ins.objectid + ins.offset;
1065                 start += cur_alloc_size;
1066         }
1067 out:
1068         return ret;
1069
1070 out_drop_extent_cache:
1071         btrfs_drop_extent_cache(inode, start, start + ram_size - 1, 0);
1072 out_reserve:
1073         btrfs_dec_block_group_reservations(root->fs_info, ins.objectid);
1074         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
1075 out_unlock:
1076         extent_clear_unlock_delalloc(inode, start, end, locked_page,
1077                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
1078                                      EXTENT_DELALLOC | EXTENT_DEFRAG,
1079                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
1080                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
1081         goto out;
1082 }
1083
1084 /*
1085  * work queue call back to started compression on a file and pages
1086  */
1087 static noinline void async_cow_start(struct btrfs_work *work)
1088 {
1089         struct async_cow *async_cow;
1090         int num_added = 0;
1091         async_cow = container_of(work, struct async_cow, work);
1092
1093         compress_file_range(async_cow->inode, async_cow->locked_page,
1094                             async_cow->start, async_cow->end, async_cow,
1095                             &num_added);
1096         if (num_added == 0) {
1097                 btrfs_add_delayed_iput(async_cow->inode);
1098                 async_cow->inode = NULL;
1099         }
1100 }
1101
1102 /*
1103  * work queue call back to submit previously compressed pages
1104  */
1105 static noinline void async_cow_submit(struct btrfs_work *work)
1106 {
1107         struct async_cow *async_cow;
1108         struct btrfs_root *root;
1109         unsigned long nr_pages;
1110
1111         async_cow = container_of(work, struct async_cow, work);
1112
1113         root = async_cow->root;
1114         nr_pages = (async_cow->end - async_cow->start + PAGE_SIZE) >>
1115                 PAGE_SHIFT;
1116
1117         /*
1118          * atomic_sub_return implies a barrier for waitqueue_active
1119          */
1120         if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <
1121             5 * SZ_1M &&
1122             waitqueue_active(&root->fs_info->async_submit_wait))
1123                 wake_up(&root->fs_info->async_submit_wait);
1124
1125         if (async_cow->inode)
1126                 submit_compressed_extents(async_cow->inode, async_cow);
1127 }
1128
1129 static noinline void async_cow_free(struct btrfs_work *work)
1130 {
1131         struct async_cow *async_cow;
1132         async_cow = container_of(work, struct async_cow, work);
1133         if (async_cow->inode)
1134                 btrfs_add_delayed_iput(async_cow->inode);
1135         kfree(async_cow);
1136 }
1137
1138 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1139                                 u64 start, u64 end, int *page_started,
1140                                 unsigned long *nr_written)
1141 {
1142         struct async_cow *async_cow;
1143         struct btrfs_root *root = BTRFS_I(inode)->root;
1144         unsigned long nr_pages;
1145         u64 cur_end;
1146         int limit = 10 * SZ_1M;
1147
1148         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1149                          1, 0, NULL, GFP_NOFS);
1150         while (start < end) {
1151                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1152                 BUG_ON(!async_cow); /* -ENOMEM */
1153                 async_cow->inode = igrab(inode);
1154                 async_cow->root = root;
1155                 async_cow->locked_page = locked_page;
1156                 async_cow->start = start;
1157
1158                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS &&
1159                     !btrfs_test_opt(root, FORCE_COMPRESS))
1160                         cur_end = end;
1161                 else
1162                         cur_end = min(end, start + SZ_512K - 1);
1163
1164                 async_cow->end = cur_end;
1165                 INIT_LIST_HEAD(&async_cow->extents);
1166
1167                 btrfs_init_work(&async_cow->work,
1168                                 btrfs_delalloc_helper,
1169                                 async_cow_start, async_cow_submit,
1170                                 async_cow_free);
1171
1172                 nr_pages = (cur_end - start + PAGE_SIZE) >>
1173                         PAGE_SHIFT;
1174                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
1175
1176                 btrfs_queue_work(root->fs_info->delalloc_workers,
1177                                  &async_cow->work);
1178
1179                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1180                         wait_event(root->fs_info->async_submit_wait,
1181                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1182                             limit));
1183                 }
1184
1185                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1186                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1187                         wait_event(root->fs_info->async_submit_wait,
1188                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1189                            0));
1190                 }
1191
1192                 *nr_written += nr_pages;
1193                 start = cur_end + 1;
1194         }
1195         *page_started = 1;
1196         return 0;
1197 }
1198
1199 static noinline int csum_exist_in_range(struct btrfs_root *root,
1200                                         u64 bytenr, u64 num_bytes)
1201 {
1202         int ret;
1203         struct btrfs_ordered_sum *sums;
1204         LIST_HEAD(list);
1205
1206         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1207                                        bytenr + num_bytes - 1, &list, 0);
1208         if (ret == 0 && list_empty(&list))
1209                 return 0;
1210
1211         while (!list_empty(&list)) {
1212                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1213                 list_del(&sums->list);
1214                 kfree(sums);
1215         }
1216         return 1;
1217 }
1218
1219 /*
1220  * when nowcow writeback call back.  This checks for snapshots or COW copies
1221  * of the extents that exist in the file, and COWs the file as required.
1222  *
1223  * If no cow copies or snapshots exist, we write directly to the existing
1224  * blocks on disk
1225  */
1226 static noinline int run_delalloc_nocow(struct inode *inode,
1227                                        struct page *locked_page,
1228                               u64 start, u64 end, int *page_started, int force,
1229                               unsigned long *nr_written)
1230 {
1231         struct btrfs_root *root = BTRFS_I(inode)->root;
1232         struct btrfs_trans_handle *trans;
1233         struct extent_buffer *leaf;
1234         struct btrfs_path *path;
1235         struct btrfs_file_extent_item *fi;
1236         struct btrfs_key found_key;
1237         u64 cow_start;
1238         u64 cur_offset;
1239         u64 extent_end;
1240         u64 extent_offset;
1241         u64 disk_bytenr;
1242         u64 num_bytes;
1243         u64 disk_num_bytes;
1244         u64 ram_bytes;
1245         int extent_type;
1246         int ret, err;
1247         int type;
1248         int nocow;
1249         int check_prev = 1;
1250         bool nolock;
1251         u64 ino = btrfs_ino(inode);
1252
1253         path = btrfs_alloc_path();
1254         if (!path) {
1255                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1256                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1257                                              EXTENT_DO_ACCOUNTING |
1258                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1259                                              PAGE_CLEAR_DIRTY |
1260                                              PAGE_SET_WRITEBACK |
1261                                              PAGE_END_WRITEBACK);
1262                 return -ENOMEM;
1263         }
1264
1265         nolock = btrfs_is_free_space_inode(inode);
1266
1267         if (nolock)
1268                 trans = btrfs_join_transaction_nolock(root);
1269         else
1270                 trans = btrfs_join_transaction(root);
1271
1272         if (IS_ERR(trans)) {
1273                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1274                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1275                                              EXTENT_DO_ACCOUNTING |
1276                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1277                                              PAGE_CLEAR_DIRTY |
1278                                              PAGE_SET_WRITEBACK |
1279                                              PAGE_END_WRITEBACK);
1280                 btrfs_free_path(path);
1281                 return PTR_ERR(trans);
1282         }
1283
1284         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1285
1286         cow_start = (u64)-1;
1287         cur_offset = start;
1288         while (1) {
1289                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1290                                                cur_offset, 0);
1291                 if (ret < 0)
1292                         goto error;
1293                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1294                         leaf = path->nodes[0];
1295                         btrfs_item_key_to_cpu(leaf, &found_key,
1296                                               path->slots[0] - 1);
1297                         if (found_key.objectid == ino &&
1298                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1299                                 path->slots[0]--;
1300                 }
1301                 check_prev = 0;
1302 next_slot:
1303                 leaf = path->nodes[0];
1304                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1305                         ret = btrfs_next_leaf(root, path);
1306                         if (ret < 0)
1307                                 goto error;
1308                         if (ret > 0)
1309                                 break;
1310                         leaf = path->nodes[0];
1311                 }
1312
1313                 nocow = 0;
1314                 disk_bytenr = 0;
1315                 num_bytes = 0;
1316                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1317
1318                 if (found_key.objectid > ino)
1319                         break;
1320                 if (WARN_ON_ONCE(found_key.objectid < ino) ||
1321                     found_key.type < BTRFS_EXTENT_DATA_KEY) {
1322                         path->slots[0]++;
1323                         goto next_slot;
1324                 }
1325                 if (found_key.type > BTRFS_EXTENT_DATA_KEY ||
1326                     found_key.offset > end)
1327                         break;
1328
1329                 if (found_key.offset > cur_offset) {
1330                         extent_end = found_key.offset;
1331                         extent_type = 0;
1332                         goto out_check;
1333                 }
1334
1335                 fi = btrfs_item_ptr(leaf, path->slots[0],
1336                                     struct btrfs_file_extent_item);
1337                 extent_type = btrfs_file_extent_type(leaf, fi);
1338
1339                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1340                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1341                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1342                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1343                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1344                         extent_end = found_key.offset +
1345                                 btrfs_file_extent_num_bytes(leaf, fi);
1346                         disk_num_bytes =
1347                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1348                         if (extent_end <= start) {
1349                                 path->slots[0]++;
1350                                 goto next_slot;
1351                         }
1352                         if (disk_bytenr == 0)
1353                                 goto out_check;
1354                         if (btrfs_file_extent_compression(leaf, fi) ||
1355                             btrfs_file_extent_encryption(leaf, fi) ||
1356                             btrfs_file_extent_other_encoding(leaf, fi))
1357                                 goto out_check;
1358                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1359                                 goto out_check;
1360                         if (btrfs_extent_readonly(root, disk_bytenr))
1361                                 goto out_check;
1362                         if (btrfs_cross_ref_exist(trans, root, ino,
1363                                                   found_key.offset -
1364                                                   extent_offset, disk_bytenr))
1365                                 goto out_check;
1366                         disk_bytenr += extent_offset;
1367                         disk_bytenr += cur_offset - found_key.offset;
1368                         num_bytes = min(end + 1, extent_end) - cur_offset;
1369                         /*
1370                          * if there are pending snapshots for this root,
1371                          * we fall into common COW way.
1372                          */
1373                         if (!nolock) {
1374                                 err = btrfs_start_write_no_snapshoting(root);
1375                                 if (!err)
1376                                         goto out_check;
1377                         }
1378                         /*
1379                          * force cow if csum exists in the range.
1380                          * this ensure that csum for a given extent are
1381                          * either valid or do not exist.
1382                          */
1383                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1384                                 goto out_check;
1385                         if (!btrfs_inc_nocow_writers(root->fs_info,
1386                                                      disk_bytenr))
1387                                 goto out_check;
1388                         nocow = 1;
1389                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1390                         extent_end = found_key.offset +
1391                                 btrfs_file_extent_inline_len(leaf,
1392                                                      path->slots[0], fi);
1393                         extent_end = ALIGN(extent_end, root->sectorsize);
1394                 } else {
1395                         BUG_ON(1);
1396                 }
1397 out_check:
1398                 if (extent_end <= start) {
1399                         path->slots[0]++;
1400                         if (!nolock && nocow)
1401                                 btrfs_end_write_no_snapshoting(root);
1402                         if (nocow)
1403                                 btrfs_dec_nocow_writers(root->fs_info,
1404                                                         disk_bytenr);
1405                         goto next_slot;
1406                 }
1407                 if (!nocow) {
1408                         if (cow_start == (u64)-1)
1409                                 cow_start = cur_offset;
1410                         cur_offset = extent_end;
1411                         if (cur_offset > end)
1412                                 break;
1413                         path->slots[0]++;
1414                         goto next_slot;
1415                 }
1416
1417                 btrfs_release_path(path);
1418                 if (cow_start != (u64)-1) {
1419                         ret = cow_file_range(inode, locked_page,
1420                                              cow_start, found_key.offset - 1,
1421                                              page_started, nr_written, 1);
1422                         if (ret) {
1423                                 if (!nolock && nocow)
1424                                         btrfs_end_write_no_snapshoting(root);
1425                                 if (nocow)
1426                                         btrfs_dec_nocow_writers(root->fs_info,
1427                                                                 disk_bytenr);
1428                                 goto error;
1429                         }
1430                         cow_start = (u64)-1;
1431                 }
1432
1433                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1434                         struct extent_map *em;
1435                         struct extent_map_tree *em_tree;
1436                         em_tree = &BTRFS_I(inode)->extent_tree;
1437                         em = alloc_extent_map();
1438                         BUG_ON(!em); /* -ENOMEM */
1439                         em->start = cur_offset;
1440                         em->orig_start = found_key.offset - extent_offset;
1441                         em->len = num_bytes;
1442                         em->block_len = num_bytes;
1443                         em->block_start = disk_bytenr;
1444                         em->orig_block_len = disk_num_bytes;
1445                         em->ram_bytes = ram_bytes;
1446                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1447                         em->mod_start = em->start;
1448                         em->mod_len = em->len;
1449                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1450                         set_bit(EXTENT_FLAG_FILLING, &em->flags);
1451                         em->generation = -1;
1452                         while (1) {
1453                                 write_lock(&em_tree->lock);
1454                                 ret = add_extent_mapping(em_tree, em, 1);
1455                                 write_unlock(&em_tree->lock);
1456                                 if (ret != -EEXIST) {
1457                                         free_extent_map(em);
1458                                         break;
1459                                 }
1460                                 btrfs_drop_extent_cache(inode, em->start,
1461                                                 em->start + em->len - 1, 0);
1462                         }
1463                         type = BTRFS_ORDERED_PREALLOC;
1464                 } else {
1465                         type = BTRFS_ORDERED_NOCOW;
1466                 }
1467
1468                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1469                                                num_bytes, num_bytes, type);
1470                 if (nocow)
1471                         btrfs_dec_nocow_writers(root->fs_info, disk_bytenr);
1472                 BUG_ON(ret); /* -ENOMEM */
1473
1474                 if (root->root_key.objectid ==
1475                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1476                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1477                                                       num_bytes);
1478                         if (ret) {
1479                                 if (!nolock && nocow)
1480                                         btrfs_end_write_no_snapshoting(root);
1481                                 goto error;
1482                         }
1483                 }
1484
1485                 extent_clear_unlock_delalloc(inode, cur_offset,
1486                                              cur_offset + num_bytes - 1,
1487                                              locked_page, EXTENT_LOCKED |
1488                                              EXTENT_DELALLOC, PAGE_UNLOCK |
1489                                              PAGE_SET_PRIVATE2);
1490                 if (!nolock && nocow)
1491                         btrfs_end_write_no_snapshoting(root);
1492                 cur_offset = extent_end;
1493                 if (cur_offset > end)
1494                         break;
1495         }
1496         btrfs_release_path(path);
1497
1498         if (cur_offset <= end && cow_start == (u64)-1) {
1499                 cow_start = cur_offset;
1500                 cur_offset = end;
1501         }
1502
1503         if (cow_start != (u64)-1) {
1504                 ret = cow_file_range(inode, locked_page, cow_start, end,
1505                                      page_started, nr_written, 1);
1506                 if (ret)
1507                         goto error;
1508         }
1509
1510 error:
1511         err = btrfs_end_transaction(trans, root);
1512         if (!ret)
1513                 ret = err;
1514
1515         if (ret && cur_offset < end)
1516                 extent_clear_unlock_delalloc(inode, cur_offset, end,
1517                                              locked_page, EXTENT_LOCKED |
1518                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1519                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1520                                              PAGE_CLEAR_DIRTY |
1521                                              PAGE_SET_WRITEBACK |
1522                                              PAGE_END_WRITEBACK);
1523         btrfs_free_path(path);
1524         return ret;
1525 }
1526
1527 static inline int need_force_cow(struct inode *inode, u64 start, u64 end)
1528 {
1529
1530         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
1531             !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC))
1532                 return 0;
1533
1534         /*
1535          * @defrag_bytes is a hint value, no spinlock held here,
1536          * if is not zero, it means the file is defragging.
1537          * Force cow if given extent needs to be defragged.
1538          */
1539         if (BTRFS_I(inode)->defrag_bytes &&
1540             test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
1541                            EXTENT_DEFRAG, 0, NULL))
1542                 return 1;
1543
1544         return 0;
1545 }
1546
1547 /*
1548  * extent_io.c call back to do delayed allocation processing
1549  */
1550 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1551                               u64 start, u64 end, int *page_started,
1552                               unsigned long *nr_written)
1553 {
1554         int ret;
1555         int force_cow = need_force_cow(inode, start, end);
1556
1557         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW && !force_cow) {
1558                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1559                                          page_started, 1, nr_written);
1560         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC && !force_cow) {
1561                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1562                                          page_started, 0, nr_written);
1563         } else if (!inode_need_compress(inode)) {
1564                 ret = cow_file_range(inode, locked_page, start, end,
1565                                       page_started, nr_written, 1);
1566         } else {
1567                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1568                         &BTRFS_I(inode)->runtime_flags);
1569                 ret = cow_file_range_async(inode, locked_page, start, end,
1570                                            page_started, nr_written);
1571         }
1572         return ret;
1573 }
1574
1575 static void btrfs_split_extent_hook(struct inode *inode,
1576                                     struct extent_state *orig, u64 split)
1577 {
1578         u64 size;
1579
1580         /* not delalloc, ignore it */
1581         if (!(orig->state & EXTENT_DELALLOC))
1582                 return;
1583
1584         size = orig->end - orig->start + 1;
1585         if (size > BTRFS_MAX_EXTENT_SIZE) {
1586                 u64 num_extents;
1587                 u64 new_size;
1588
1589                 /*
1590                  * See the explanation in btrfs_merge_extent_hook, the same
1591                  * applies here, just in reverse.
1592                  */
1593                 new_size = orig->end - split + 1;
1594                 num_extents = div64_u64(new_size + BTRFS_MAX_EXTENT_SIZE - 1,
1595                                         BTRFS_MAX_EXTENT_SIZE);
1596                 new_size = split - orig->start;
1597                 num_extents += div64_u64(new_size + BTRFS_MAX_EXTENT_SIZE - 1,
1598                                         BTRFS_MAX_EXTENT_SIZE);
1599                 if (div64_u64(size + BTRFS_MAX_EXTENT_SIZE - 1,
1600                               BTRFS_MAX_EXTENT_SIZE) >= num_extents)
1601                         return;
1602         }
1603
1604         spin_lock(&BTRFS_I(inode)->lock);
1605         BTRFS_I(inode)->outstanding_extents++;
1606         spin_unlock(&BTRFS_I(inode)->lock);
1607 }
1608
1609 /*
1610  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1611  * extents so we can keep track of new extents that are just merged onto old
1612  * extents, such as when we are doing sequential writes, so we can properly
1613  * account for the metadata space we'll need.
1614  */
1615 static void btrfs_merge_extent_hook(struct inode *inode,
1616                                     struct extent_state *new,
1617                                     struct extent_state *other)
1618 {
1619         u64 new_size, old_size;
1620         u64 num_extents;
1621
1622         /* not delalloc, ignore it */
1623         if (!(other->state & EXTENT_DELALLOC))
1624                 return;
1625
1626         if (new->start > other->start)
1627                 new_size = new->end - other->start + 1;
1628         else
1629                 new_size = other->end - new->start + 1;
1630
1631         /* we're not bigger than the max, unreserve the space and go */
1632         if (new_size <= BTRFS_MAX_EXTENT_SIZE) {
1633                 spin_lock(&BTRFS_I(inode)->lock);
1634                 BTRFS_I(inode)->outstanding_extents--;
1635                 spin_unlock(&BTRFS_I(inode)->lock);
1636                 return;
1637         }
1638
1639         /*
1640          * We have to add up either side to figure out how many extents were
1641          * accounted for before we merged into one big extent.  If the number of
1642          * extents we accounted for is <= the amount we need for the new range
1643          * then we can return, otherwise drop.  Think of it like this
1644          *
1645          * [ 4k][MAX_SIZE]
1646          *
1647          * So we've grown the extent by a MAX_SIZE extent, this would mean we
1648          * need 2 outstanding extents, on one side we have 1 and the other side
1649          * we have 1 so they are == and we can return.  But in this case
1650          *
1651          * [MAX_SIZE+4k][MAX_SIZE+4k]
1652          *
1653          * Each range on their own accounts for 2 extents, but merged together
1654          * they are only 3 extents worth of accounting, so we need to drop in
1655          * this case.
1656          */
1657         old_size = other->end - other->start + 1;
1658         num_extents = div64_u64(old_size + BTRFS_MAX_EXTENT_SIZE - 1,
1659                                 BTRFS_MAX_EXTENT_SIZE);
1660         old_size = new->end - new->start + 1;
1661         num_extents += div64_u64(old_size + BTRFS_MAX_EXTENT_SIZE - 1,
1662                                  BTRFS_MAX_EXTENT_SIZE);
1663
1664         if (div64_u64(new_size + BTRFS_MAX_EXTENT_SIZE - 1,
1665                       BTRFS_MAX_EXTENT_SIZE) >= num_extents)
1666                 return;
1667
1668         spin_lock(&BTRFS_I(inode)->lock);
1669         BTRFS_I(inode)->outstanding_extents--;
1670         spin_unlock(&BTRFS_I(inode)->lock);
1671 }
1672
1673 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1674                                       struct inode *inode)
1675 {
1676         spin_lock(&root->delalloc_lock);
1677         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1678                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1679                               &root->delalloc_inodes);
1680                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1681                         &BTRFS_I(inode)->runtime_flags);
1682                 root->nr_delalloc_inodes++;
1683                 if (root->nr_delalloc_inodes == 1) {
1684                         spin_lock(&root->fs_info->delalloc_root_lock);
1685                         BUG_ON(!list_empty(&root->delalloc_root));
1686                         list_add_tail(&root->delalloc_root,
1687                                       &root->fs_info->delalloc_roots);
1688                         spin_unlock(&root->fs_info->delalloc_root_lock);
1689                 }
1690         }
1691         spin_unlock(&root->delalloc_lock);
1692 }
1693
1694 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1695                                      struct inode *inode)
1696 {
1697         spin_lock(&root->delalloc_lock);
1698         if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1699                 list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1700                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1701                           &BTRFS_I(inode)->runtime_flags);
1702                 root->nr_delalloc_inodes--;
1703                 if (!root->nr_delalloc_inodes) {
1704                         spin_lock(&root->fs_info->delalloc_root_lock);
1705                         BUG_ON(list_empty(&root->delalloc_root));
1706                         list_del_init(&root->delalloc_root);
1707                         spin_unlock(&root->fs_info->delalloc_root_lock);
1708                 }
1709         }
1710         spin_unlock(&root->delalloc_lock);
1711 }
1712
1713 /*
1714  * extent_io.c set_bit_hook, used to track delayed allocation
1715  * bytes in this file, and to maintain the list of inodes that
1716  * have pending delalloc work to be done.
1717  */
1718 static void btrfs_set_bit_hook(struct inode *inode,
1719                                struct extent_state *state, unsigned *bits)
1720 {
1721
1722         if ((*bits & EXTENT_DEFRAG) && !(*bits & EXTENT_DELALLOC))
1723                 WARN_ON(1);
1724         /*
1725          * set_bit and clear bit hooks normally require _irqsave/restore
1726          * but in this case, we are only testing for the DELALLOC
1727          * bit, which is only set or cleared with irqs on
1728          */
1729         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1730                 struct btrfs_root *root = BTRFS_I(inode)->root;
1731                 u64 len = state->end + 1 - state->start;
1732                 bool do_list = !btrfs_is_free_space_inode(inode);
1733
1734                 if (*bits & EXTENT_FIRST_DELALLOC) {
1735                         *bits &= ~EXTENT_FIRST_DELALLOC;
1736                 } else {
1737                         spin_lock(&BTRFS_I(inode)->lock);
1738                         BTRFS_I(inode)->outstanding_extents++;
1739                         spin_unlock(&BTRFS_I(inode)->lock);
1740                 }
1741
1742                 /* For sanity tests */
1743                 if (btrfs_test_is_dummy_root(root))
1744                         return;
1745
1746                 __percpu_counter_add(&root->fs_info->delalloc_bytes, len,
1747                                      root->fs_info->delalloc_batch);
1748                 spin_lock(&BTRFS_I(inode)->lock);
1749                 BTRFS_I(inode)->delalloc_bytes += len;
1750                 if (*bits & EXTENT_DEFRAG)
1751                         BTRFS_I(inode)->defrag_bytes += len;
1752                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1753                                          &BTRFS_I(inode)->runtime_flags))
1754                         btrfs_add_delalloc_inodes(root, inode);
1755                 spin_unlock(&BTRFS_I(inode)->lock);
1756         }
1757 }
1758
1759 /*
1760  * extent_io.c clear_bit_hook, see set_bit_hook for why
1761  */
1762 static void btrfs_clear_bit_hook(struct inode *inode,
1763                                  struct extent_state *state,
1764                                  unsigned *bits)
1765 {
1766         u64 len = state->end + 1 - state->start;
1767         u64 num_extents = div64_u64(len + BTRFS_MAX_EXTENT_SIZE -1,
1768                                     BTRFS_MAX_EXTENT_SIZE);
1769
1770         spin_lock(&BTRFS_I(inode)->lock);
1771         if ((state->state & EXTENT_DEFRAG) && (*bits & EXTENT_DEFRAG))
1772                 BTRFS_I(inode)->defrag_bytes -= len;
1773         spin_unlock(&BTRFS_I(inode)->lock);
1774
1775         /*
1776          * set_bit and clear bit hooks normally require _irqsave/restore
1777          * but in this case, we are only testing for the DELALLOC
1778          * bit, which is only set or cleared with irqs on
1779          */
1780         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1781                 struct btrfs_root *root = BTRFS_I(inode)->root;
1782                 bool do_list = !btrfs_is_free_space_inode(inode);
1783
1784                 if (*bits & EXTENT_FIRST_DELALLOC) {
1785                         *bits &= ~EXTENT_FIRST_DELALLOC;
1786                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1787                         spin_lock(&BTRFS_I(inode)->lock);
1788                         BTRFS_I(inode)->outstanding_extents -= num_extents;
1789                         spin_unlock(&BTRFS_I(inode)->lock);
1790                 }
1791
1792                 /*
1793                  * We don't reserve metadata space for space cache inodes so we
1794                  * don't need to call dellalloc_release_metadata if there is an
1795                  * error.
1796                  */
1797                 if (*bits & EXTENT_DO_ACCOUNTING &&
1798                     root != root->fs_info->tree_root)
1799                         btrfs_delalloc_release_metadata(inode, len);
1800
1801                 /* For sanity tests. */
1802                 if (btrfs_test_is_dummy_root(root))
1803                         return;
1804
1805                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1806                     && do_list && !(state->state & EXTENT_NORESERVE))
1807                         btrfs_free_reserved_data_space_noquota(inode,
1808                                         state->start, len);
1809
1810                 __percpu_counter_add(&root->fs_info->delalloc_bytes, -len,
1811                                      root->fs_info->delalloc_batch);
1812                 spin_lock(&BTRFS_I(inode)->lock);
1813                 BTRFS_I(inode)->delalloc_bytes -= len;
1814                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1815                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1816                              &BTRFS_I(inode)->runtime_flags))
1817                         btrfs_del_delalloc_inode(root, inode);
1818                 spin_unlock(&BTRFS_I(inode)->lock);
1819         }
1820 }
1821
1822 /*
1823  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1824  * we don't create bios that span stripes or chunks
1825  */
1826 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1827                          size_t size, struct bio *bio,
1828                          unsigned long bio_flags)
1829 {
1830         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1831         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1832         u64 length = 0;
1833         u64 map_length;
1834         int ret;
1835
1836         if (bio_flags & EXTENT_BIO_COMPRESSED)
1837                 return 0;
1838
1839         length = bio->bi_iter.bi_size;
1840         map_length = length;
1841         ret = btrfs_map_block(root->fs_info, bio_op(bio), logical,
1842                               &map_length, NULL, 0);
1843         /* Will always return 0 with map_multi == NULL */
1844         BUG_ON(ret < 0);
1845         if (map_length < length + size)
1846                 return 1;
1847         return 0;
1848 }
1849
1850 /*
1851  * in order to insert checksums into the metadata in large chunks,
1852  * we wait until bio submission time.   All the pages in the bio are
1853  * checksummed and sums are attached onto the ordered extent record.
1854  *
1855  * At IO completion time the cums attached on the ordered extent record
1856  * are inserted into the btree
1857  */
1858 static int __btrfs_submit_bio_start(struct inode *inode, struct bio *bio,
1859                                     int mirror_num, unsigned long bio_flags,
1860                                     u64 bio_offset)
1861 {
1862         struct btrfs_root *root = BTRFS_I(inode)->root;
1863         int ret = 0;
1864
1865         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1866         BUG_ON(ret); /* -ENOMEM */
1867         return 0;
1868 }
1869
1870 /*
1871  * in order to insert checksums into the metadata in large chunks,
1872  * we wait until bio submission time.   All the pages in the bio are
1873  * checksummed and sums are attached onto the ordered extent record.
1874  *
1875  * At IO completion time the cums attached on the ordered extent record
1876  * are inserted into the btree
1877  */
1878 static int __btrfs_submit_bio_done(struct inode *inode, struct bio *bio,
1879                           int mirror_num, unsigned long bio_flags,
1880                           u64 bio_offset)
1881 {
1882         struct btrfs_root *root = BTRFS_I(inode)->root;
1883         int ret;
1884
1885         ret = btrfs_map_bio(root, bio, mirror_num, 1);
1886         if (ret) {
1887                 bio->bi_error = ret;
1888                 bio_endio(bio);
1889         }
1890         return ret;
1891 }
1892
1893 /*
1894  * extent_io.c submission hook. This does the right thing for csum calculation
1895  * on write, or reading the csums from the tree before a read
1896  */
1897 static int btrfs_submit_bio_hook(struct inode *inode, struct bio *bio,
1898                           int mirror_num, unsigned long bio_flags,
1899                           u64 bio_offset)
1900 {
1901         struct btrfs_root *root = BTRFS_I(inode)->root;
1902         enum btrfs_wq_endio_type metadata = BTRFS_WQ_ENDIO_DATA;
1903         int ret = 0;
1904         int skip_sum;
1905         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1906
1907         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1908
1909         if (btrfs_is_free_space_inode(inode))
1910                 metadata = BTRFS_WQ_ENDIO_FREE_SPACE;
1911
1912         if (bio_op(bio) != REQ_OP_WRITE) {
1913                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, metadata);
1914                 if (ret)
1915                         goto out;
1916
1917                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1918                         ret = btrfs_submit_compressed_read(inode, bio,
1919                                                            mirror_num,
1920                                                            bio_flags);
1921                         goto out;
1922                 } else if (!skip_sum) {
1923                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1924                         if (ret)
1925                                 goto out;
1926                 }
1927                 goto mapit;
1928         } else if (async && !skip_sum) {
1929                 /* csum items have already been cloned */
1930                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1931                         goto mapit;
1932                 /* we're doing a write, do the async checksumming */
1933                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1934                                    inode, bio, mirror_num,
1935                                    bio_flags, bio_offset,
1936                                    __btrfs_submit_bio_start,
1937                                    __btrfs_submit_bio_done);
1938                 goto out;
1939         } else if (!skip_sum) {
1940                 ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1941                 if (ret)
1942                         goto out;
1943         }
1944
1945 mapit:
1946         ret = btrfs_map_bio(root, bio, mirror_num, 0);
1947
1948 out:
1949         if (ret < 0) {
1950                 bio->bi_error = ret;
1951                 bio_endio(bio);
1952         }
1953         return ret;
1954 }
1955
1956 /*
1957  * given a list of ordered sums record them in the inode.  This happens
1958  * at IO completion time based on sums calculated at bio submission time.
1959  */
1960 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1961                              struct inode *inode, u64 file_offset,
1962                              struct list_head *list)
1963 {
1964         struct btrfs_ordered_sum *sum;
1965
1966         list_for_each_entry(sum, list, list) {
1967                 trans->adding_csums = 1;
1968                 btrfs_csum_file_blocks(trans,
1969                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1970                 trans->adding_csums = 0;
1971         }
1972         return 0;
1973 }
1974
1975 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1976                               struct extent_state **cached_state)
1977 {
1978         WARN_ON((end & (PAGE_SIZE - 1)) == 0);
1979         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1980                                    cached_state);
1981 }
1982
1983 /* see btrfs_writepage_start_hook for details on why this is required */
1984 struct btrfs_writepage_fixup {
1985         struct page *page;
1986         struct btrfs_work work;
1987 };
1988
1989 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1990 {
1991         struct btrfs_writepage_fixup *fixup;
1992         struct btrfs_ordered_extent *ordered;
1993         struct extent_state *cached_state = NULL;
1994         struct page *page;
1995         struct inode *inode;
1996         u64 page_start;
1997         u64 page_end;
1998         int ret;
1999
2000         fixup = container_of(work, struct btrfs_writepage_fixup, work);
2001         page = fixup->page;
2002 again:
2003         lock_page(page);
2004         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
2005                 ClearPageChecked(page);
2006                 goto out_page;
2007         }
2008
2009         inode = page->mapping->host;
2010         page_start = page_offset(page);
2011         page_end = page_offset(page) + PAGE_SIZE - 1;
2012
2013         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end,
2014                          &cached_state);
2015
2016         /* already ordered? We're done */
2017         if (PagePrivate2(page))
2018                 goto out;
2019
2020         ordered = btrfs_lookup_ordered_range(inode, page_start,
2021                                         PAGE_SIZE);
2022         if (ordered) {
2023                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
2024                                      page_end, &cached_state, GFP_NOFS);
2025                 unlock_page(page);
2026                 btrfs_start_ordered_extent(inode, ordered, 1);
2027                 btrfs_put_ordered_extent(ordered);
2028                 goto again;
2029         }
2030
2031         ret = btrfs_delalloc_reserve_space(inode, page_start,
2032                                            PAGE_SIZE);
2033         if (ret) {
2034                 mapping_set_error(page->mapping, ret);
2035                 end_extent_writepage(page, ret, page_start, page_end);
2036                 ClearPageChecked(page);
2037                 goto out;
2038          }
2039
2040         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
2041         ClearPageChecked(page);
2042         set_page_dirty(page);
2043 out:
2044         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
2045                              &cached_state, GFP_NOFS);
2046 out_page:
2047         unlock_page(page);
2048         put_page(page);
2049         kfree(fixup);
2050 }
2051
2052 /*
2053  * There are a few paths in the higher layers of the kernel that directly
2054  * set the page dirty bit without asking the filesystem if it is a
2055  * good idea.  This causes problems because we want to make sure COW
2056  * properly happens and the data=ordered rules are followed.
2057  *
2058  * In our case any range that doesn't have the ORDERED bit set
2059  * hasn't been properly setup for IO.  We kick off an async process
2060  * to fix it up.  The async helper will wait for ordered extents, set
2061  * the delalloc bit and make it safe to write the page.
2062  */
2063 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
2064 {
2065         struct inode *inode = page->mapping->host;
2066         struct btrfs_writepage_fixup *fixup;
2067         struct btrfs_root *root = BTRFS_I(inode)->root;
2068
2069         /* this page is properly in the ordered list */
2070         if (TestClearPagePrivate2(page))
2071                 return 0;
2072
2073         if (PageChecked(page))
2074                 return -EAGAIN;
2075
2076         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
2077         if (!fixup)
2078                 return -EAGAIN;
2079
2080         SetPageChecked(page);
2081         get_page(page);
2082         btrfs_init_work(&fixup->work, btrfs_fixup_helper,
2083                         btrfs_writepage_fixup_worker, NULL, NULL);
2084         fixup->page = page;
2085         btrfs_queue_work(root->fs_info->fixup_workers, &fixup->work);
2086         return -EBUSY;
2087 }
2088
2089 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
2090                                        struct inode *inode, u64 file_pos,
2091                                        u64 disk_bytenr, u64 disk_num_bytes,
2092                                        u64 num_bytes, u64 ram_bytes,
2093                                        u8 compression, u8 encryption,
2094                                        u16 other_encoding, int extent_type)
2095 {
2096         struct btrfs_root *root = BTRFS_I(inode)->root;
2097         struct btrfs_file_extent_item *fi;
2098         struct btrfs_path *path;
2099         struct extent_buffer *leaf;
2100         struct btrfs_key ins;
2101         int extent_inserted = 0;
2102         int ret;
2103
2104         path = btrfs_alloc_path();
2105         if (!path)
2106                 return -ENOMEM;
2107
2108         /*
2109          * we may be replacing one extent in the tree with another.
2110          * The new extent is pinned in the extent map, and we don't want
2111          * to drop it from the cache until it is completely in the btree.
2112          *
2113          * So, tell btrfs_drop_extents to leave this extent in the cache.
2114          * the caller is expected to unpin it and allow it to be merged
2115          * with the others.
2116          */
2117         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
2118                                    file_pos + num_bytes, NULL, 0,
2119                                    1, sizeof(*fi), &extent_inserted);
2120         if (ret)
2121                 goto out;
2122
2123         if (!extent_inserted) {
2124                 ins.objectid = btrfs_ino(inode);
2125                 ins.offset = file_pos;
2126                 ins.type = BTRFS_EXTENT_DATA_KEY;
2127
2128                 path->leave_spinning = 1;
2129                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
2130                                               sizeof(*fi));
2131                 if (ret)
2132                         goto out;
2133         }
2134         leaf = path->nodes[0];
2135         fi = btrfs_item_ptr(leaf, path->slots[0],
2136                             struct btrfs_file_extent_item);
2137         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2138         btrfs_set_file_extent_type(leaf, fi, extent_type);
2139         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
2140         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
2141         btrfs_set_file_extent_offset(leaf, fi, 0);
2142         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2143         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
2144         btrfs_set_file_extent_compression(leaf, fi, compression);
2145         btrfs_set_file_extent_encryption(leaf, fi, encryption);
2146         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
2147
2148         btrfs_mark_buffer_dirty(leaf);
2149         btrfs_release_path(path);
2150
2151         inode_add_bytes(inode, num_bytes);
2152
2153         ins.objectid = disk_bytenr;
2154         ins.offset = disk_num_bytes;
2155         ins.type = BTRFS_EXTENT_ITEM_KEY;
2156         ret = btrfs_alloc_reserved_file_extent(trans, root,
2157                                         root->root_key.objectid,
2158                                         btrfs_ino(inode), file_pos,
2159                                         ram_bytes, &ins);
2160         /*
2161          * Release the reserved range from inode dirty range map, as it is
2162          * already moved into delayed_ref_head
2163          */
2164         btrfs_qgroup_release_data(inode, file_pos, ram_bytes);
2165 out:
2166         btrfs_free_path(path);
2167
2168         return ret;
2169 }
2170
2171 /* snapshot-aware defrag */
2172 struct sa_defrag_extent_backref {
2173         struct rb_node node;
2174         struct old_sa_defrag_extent *old;
2175         u64 root_id;
2176         u64 inum;
2177         u64 file_pos;
2178         u64 extent_offset;
2179         u64 num_bytes;
2180         u64 generation;
2181 };
2182
2183 struct old_sa_defrag_extent {
2184         struct list_head list;
2185         struct new_sa_defrag_extent *new;
2186
2187         u64 extent_offset;
2188         u64 bytenr;
2189         u64 offset;
2190         u64 len;
2191         int count;
2192 };
2193
2194 struct new_sa_defrag_extent {
2195         struct rb_root root;
2196         struct list_head head;
2197         struct btrfs_path *path;
2198         struct inode *inode;
2199         u64 file_pos;
2200         u64 len;
2201         u64 bytenr;
2202         u64 disk_len;
2203         u8 compress_type;
2204 };
2205
2206 static int backref_comp(struct sa_defrag_extent_backref *b1,
2207                         struct sa_defrag_extent_backref *b2)
2208 {
2209         if (b1->root_id < b2->root_id)
2210                 return -1;
2211         else if (b1->root_id > b2->root_id)
2212                 return 1;
2213
2214         if (b1->inum < b2->inum)
2215                 return -1;
2216         else if (b1->inum > b2->inum)
2217                 return 1;
2218
2219         if (b1->file_pos < b2->file_pos)
2220                 return -1;
2221         else if (b1->file_pos > b2->file_pos)
2222                 return 1;
2223
2224         /*
2225          * [------------------------------] ===> (a range of space)
2226          *     |<--->|   |<---->| =============> (fs/file tree A)
2227          * |<---------------------------->| ===> (fs/file tree B)
2228          *
2229          * A range of space can refer to two file extents in one tree while
2230          * refer to only one file extent in another tree.
2231          *
2232          * So we may process a disk offset more than one time(two extents in A)
2233          * and locate at the same extent(one extent in B), then insert two same
2234          * backrefs(both refer to the extent in B).
2235          */
2236         return 0;
2237 }
2238
2239 static void backref_insert(struct rb_root *root,
2240                            struct sa_defrag_extent_backref *backref)
2241 {
2242         struct rb_node **p = &root->rb_node;
2243         struct rb_node *parent = NULL;
2244         struct sa_defrag_extent_backref *entry;
2245         int ret;
2246
2247         while (*p) {
2248                 parent = *p;
2249                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2250
2251                 ret = backref_comp(backref, entry);
2252                 if (ret < 0)
2253                         p = &(*p)->rb_left;
2254                 else
2255                         p = &(*p)->rb_right;
2256         }
2257
2258         rb_link_node(&backref->node, parent, p);
2259         rb_insert_color(&backref->node, root);
2260 }
2261
2262 /*
2263  * Note the backref might has changed, and in this case we just return 0.
2264  */
2265 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2266                                        void *ctx)
2267 {
2268         struct btrfs_file_extent_item *extent;
2269         struct btrfs_fs_info *fs_info;
2270         struct old_sa_defrag_extent *old = ctx;
2271         struct new_sa_defrag_extent *new = old->new;
2272         struct btrfs_path *path = new->path;
2273         struct btrfs_key key;
2274         struct btrfs_root *root;
2275         struct sa_defrag_extent_backref *backref;
2276         struct extent_buffer *leaf;
2277         struct inode *inode = new->inode;
2278         int slot;
2279         int ret;
2280         u64 extent_offset;
2281         u64 num_bytes;
2282
2283         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2284             inum == btrfs_ino(inode))
2285                 return 0;
2286
2287         key.objectid = root_id;
2288         key.type = BTRFS_ROOT_ITEM_KEY;
2289         key.offset = (u64)-1;
2290
2291         fs_info = BTRFS_I(inode)->root->fs_info;
2292         root = btrfs_read_fs_root_no_name(fs_info, &key);
2293         if (IS_ERR(root)) {
2294                 if (PTR_ERR(root) == -ENOENT)
2295                         return 0;
2296                 WARN_ON(1);
2297                 pr_debug("inum=%llu, offset=%llu, root_id=%llu\n",
2298                          inum, offset, root_id);
2299                 return PTR_ERR(root);
2300         }
2301
2302         key.objectid = inum;
2303         key.type = BTRFS_EXTENT_DATA_KEY;
2304         if (offset > (u64)-1 << 32)
2305                 key.offset = 0;
2306         else
2307                 key.offset = offset;
2308
2309         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2310         if (WARN_ON(ret < 0))
2311                 return ret;
2312         ret = 0;
2313
2314         while (1) {
2315                 cond_resched();
2316
2317                 leaf = path->nodes[0];
2318                 slot = path->slots[0];
2319
2320                 if (slot >= btrfs_header_nritems(leaf)) {
2321                         ret = btrfs_next_leaf(root, path);
2322                         if (ret < 0) {
2323                                 goto out;
2324                         } else if (ret > 0) {
2325                                 ret = 0;
2326                                 goto out;
2327                         }
2328                         continue;
2329                 }
2330
2331                 path->slots[0]++;
2332
2333                 btrfs_item_key_to_cpu(leaf, &key, slot);
2334
2335                 if (key.objectid > inum)
2336                         goto out;
2337
2338                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2339                         continue;
2340
2341                 extent = btrfs_item_ptr(leaf, slot,
2342                                         struct btrfs_file_extent_item);
2343
2344                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2345                         continue;
2346
2347                 /*
2348                  * 'offset' refers to the exact key.offset,
2349                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2350                  * (key.offset - extent_offset).
2351                  */
2352                 if (key.offset != offset)
2353                         continue;
2354
2355                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2356                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2357
2358                 if (extent_offset >= old->extent_offset + old->offset +
2359                     old->len || extent_offset + num_bytes <=
2360                     old->extent_offset + old->offset)
2361                         continue;
2362                 break;
2363         }
2364
2365         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2366         if (!backref) {
2367                 ret = -ENOENT;
2368                 goto out;
2369         }
2370
2371         backref->root_id = root_id;
2372         backref->inum = inum;
2373         backref->file_pos = offset;
2374         backref->num_bytes = num_bytes;
2375         backref->extent_offset = extent_offset;
2376         backref->generation = btrfs_file_extent_generation(leaf, extent);
2377         backref->old = old;
2378         backref_insert(&new->root, backref);
2379         old->count++;
2380 out:
2381         btrfs_release_path(path);
2382         WARN_ON(ret);
2383         return ret;
2384 }
2385
2386 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2387                                    struct new_sa_defrag_extent *new)
2388 {
2389         struct btrfs_fs_info *fs_info = BTRFS_I(new->inode)->root->fs_info;
2390         struct old_sa_defrag_extent *old, *tmp;
2391         int ret;
2392
2393         new->path = path;
2394
2395         list_for_each_entry_safe(old, tmp, &new->head, list) {
2396                 ret = iterate_inodes_from_logical(old->bytenr +
2397                                                   old->extent_offset, fs_info,
2398                                                   path, record_one_backref,
2399                                                   old);
2400                 if (ret < 0 && ret != -ENOENT)
2401                         return false;
2402
2403                 /* no backref to be processed for this extent */
2404                 if (!old->count) {
2405                         list_del(&old->list);
2406                         kfree(old);
2407                 }
2408         }
2409
2410         if (list_empty(&new->head))
2411                 return false;
2412
2413         return true;
2414 }
2415
2416 static int relink_is_mergable(struct extent_buffer *leaf,
2417                               struct btrfs_file_extent_item *fi,
2418                               struct new_sa_defrag_extent *new)
2419 {
2420         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2421                 return 0;
2422
2423         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2424                 return 0;
2425
2426         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2427                 return 0;
2428
2429         if (btrfs_file_extent_encryption(leaf, fi) ||
2430             btrfs_file_extent_other_encoding(leaf, fi))
2431                 return 0;
2432
2433         return 1;
2434 }
2435
2436 /*
2437  * Note the backref might has changed, and in this case we just return 0.
2438  */
2439 static noinline int relink_extent_backref(struct btrfs_path *path,
2440                                  struct sa_defrag_extent_backref *prev,
2441                                  struct sa_defrag_extent_backref *backref)
2442 {
2443         struct btrfs_file_extent_item *extent;
2444         struct btrfs_file_extent_item *item;
2445         struct btrfs_ordered_extent *ordered;
2446         struct btrfs_trans_handle *trans;
2447         struct btrfs_fs_info *fs_info;
2448         struct btrfs_root *root;
2449         struct btrfs_key key;
2450         struct extent_buffer *leaf;
2451         struct old_sa_defrag_extent *old = backref->old;
2452         struct new_sa_defrag_extent *new = old->new;
2453         struct inode *src_inode = new->inode;
2454         struct inode *inode;
2455         struct extent_state *cached = NULL;
2456         int ret = 0;
2457         u64 start;
2458         u64 len;
2459         u64 lock_start;
2460         u64 lock_end;
2461         bool merge = false;
2462         int index;
2463
2464         if (prev && prev->root_id == backref->root_id &&
2465             prev->inum == backref->inum &&
2466             prev->file_pos + prev->num_bytes == backref->file_pos)
2467                 merge = true;
2468
2469         /* step 1: get root */
2470         key.objectid = backref->root_id;
2471         key.type = BTRFS_ROOT_ITEM_KEY;
2472         key.offset = (u64)-1;
2473
2474         fs_info = BTRFS_I(src_inode)->root->fs_info;
2475         index = srcu_read_lock(&fs_info->subvol_srcu);
2476
2477         root = btrfs_read_fs_root_no_name(fs_info, &key);
2478         if (IS_ERR(root)) {
2479                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2480                 if (PTR_ERR(root) == -ENOENT)
2481                         return 0;
2482                 return PTR_ERR(root);
2483         }
2484
2485         if (btrfs_root_readonly(root)) {
2486                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2487                 return 0;
2488         }
2489
2490         /* step 2: get inode */
2491         key.objectid = backref->inum;
2492         key.type = BTRFS_INODE_ITEM_KEY;
2493         key.offset = 0;
2494
2495         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2496         if (IS_ERR(inode)) {
2497                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2498                 return 0;
2499         }
2500
2501         srcu_read_unlock(&fs_info->subvol_srcu, index);
2502
2503         /* step 3: relink backref */
2504         lock_start = backref->file_pos;
2505         lock_end = backref->file_pos + backref->num_bytes - 1;
2506         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2507                          &cached);
2508
2509         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2510         if (ordered) {
2511                 btrfs_put_ordered_extent(ordered);
2512                 goto out_unlock;
2513         }
2514
2515         trans = btrfs_join_transaction(root);
2516         if (IS_ERR(trans)) {
2517                 ret = PTR_ERR(trans);
2518                 goto out_unlock;
2519         }
2520
2521         key.objectid = backref->inum;
2522         key.type = BTRFS_EXTENT_DATA_KEY;
2523         key.offset = backref->file_pos;
2524
2525         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2526         if (ret < 0) {
2527                 goto out_free_path;
2528         } else if (ret > 0) {
2529                 ret = 0;
2530                 goto out_free_path;
2531         }
2532
2533         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2534                                 struct btrfs_file_extent_item);
2535
2536         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2537             backref->generation)
2538                 goto out_free_path;
2539
2540         btrfs_release_path(path);
2541
2542         start = backref->file_pos;
2543         if (backref->extent_offset < old->extent_offset + old->offset)
2544                 start += old->extent_offset + old->offset -
2545                          backref->extent_offset;
2546
2547         len = min(backref->extent_offset + backref->num_bytes,
2548                   old->extent_offset + old->offset + old->len);
2549         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2550
2551         ret = btrfs_drop_extents(trans, root, inode, start,
2552                                  start + len, 1);
2553         if (ret)
2554                 goto out_free_path;
2555 again:
2556         key.objectid = btrfs_ino(inode);
2557         key.type = BTRFS_EXTENT_DATA_KEY;
2558         key.offset = start;
2559
2560         path->leave_spinning = 1;
2561         if (merge) {
2562                 struct btrfs_file_extent_item *fi;
2563                 u64 extent_len;
2564                 struct btrfs_key found_key;
2565
2566                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2567                 if (ret < 0)
2568                         goto out_free_path;
2569
2570                 path->slots[0]--;
2571                 leaf = path->nodes[0];
2572                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2573
2574                 fi = btrfs_item_ptr(leaf, path->slots[0],
2575                                     struct btrfs_file_extent_item);
2576                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2577
2578                 if (extent_len + found_key.offset == start &&
2579                     relink_is_mergable(leaf, fi, new)) {
2580                         btrfs_set_file_extent_num_bytes(leaf, fi,
2581                                                         extent_len + len);
2582                         btrfs_mark_buffer_dirty(leaf);
2583                         inode_add_bytes(inode, len);
2584
2585                         ret = 1;
2586                         goto out_free_path;
2587                 } else {
2588                         merge = false;
2589                         btrfs_release_path(path);
2590                         goto again;
2591                 }
2592         }
2593
2594         ret = btrfs_insert_empty_item(trans, root, path, &key,
2595                                         sizeof(*extent));
2596         if (ret) {
2597                 btrfs_abort_transaction(trans, root, ret);
2598                 goto out_free_path;
2599         }
2600
2601         leaf = path->nodes[0];
2602         item = btrfs_item_ptr(leaf, path->slots[0],
2603                                 struct btrfs_file_extent_item);
2604         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2605         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2606         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2607         btrfs_set_file_extent_num_bytes(leaf, item, len);
2608         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2609         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2610         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2611         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2612         btrfs_set_file_extent_encryption(leaf, item, 0);
2613         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2614
2615         btrfs_mark_buffer_dirty(leaf);
2616         inode_add_bytes(inode, len);
2617         btrfs_release_path(path);
2618
2619         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2620                         new->disk_len, 0,
2621                         backref->root_id, backref->inum,
2622                         new->file_pos); /* start - extent_offset */
2623         if (ret) {
2624                 btrfs_abort_transaction(trans, root, ret);
2625                 goto out_free_path;
2626         }
2627
2628         ret = 1;
2629 out_free_path:
2630         btrfs_release_path(path);
2631         path->leave_spinning = 0;
2632         btrfs_end_transaction(trans, root);
2633 out_unlock:
2634         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2635                              &cached, GFP_NOFS);
2636         iput(inode);
2637         return ret;
2638 }
2639
2640 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2641 {
2642         struct old_sa_defrag_extent *old, *tmp;
2643
2644         if (!new)
2645                 return;
2646
2647         list_for_each_entry_safe(old, tmp, &new->head, list) {
2648                 kfree(old);
2649         }
2650         kfree(new);
2651 }
2652
2653 static void relink_file_extents(struct new_sa_defrag_extent *new)
2654 {
2655         struct btrfs_path *path;
2656         struct sa_defrag_extent_backref *backref;
2657         struct sa_defrag_extent_backref *prev = NULL;
2658         struct inode *inode;
2659         struct btrfs_root *root;
2660         struct rb_node *node;
2661         int ret;
2662
2663         inode = new->inode;
2664         root = BTRFS_I(inode)->root;
2665
2666         path = btrfs_alloc_path();
2667         if (!path)
2668                 return;
2669
2670         if (!record_extent_backrefs(path, new)) {
2671                 btrfs_free_path(path);
2672                 goto out;
2673         }
2674         btrfs_release_path(path);
2675
2676         while (1) {
2677                 node = rb_first(&new->root);
2678                 if (!node)
2679                         break;
2680                 rb_erase(node, &new->root);
2681
2682                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2683
2684                 ret = relink_extent_backref(path, prev, backref);
2685                 WARN_ON(ret < 0);
2686
2687                 kfree(prev);
2688
2689                 if (ret == 1)
2690                         prev = backref;
2691                 else
2692                         prev = NULL;
2693                 cond_resched();
2694         }
2695         kfree(prev);
2696
2697         btrfs_free_path(path);
2698 out:
2699         free_sa_defrag_extent(new);
2700
2701         atomic_dec(&root->fs_info->defrag_running);
2702         wake_up(&root->fs_info->transaction_wait);
2703 }
2704
2705 static struct new_sa_defrag_extent *
2706 record_old_file_extents(struct inode *inode,
2707                         struct btrfs_ordered_extent *ordered)
2708 {
2709         struct btrfs_root *root = BTRFS_I(inode)->root;
2710         struct btrfs_path *path;
2711         struct btrfs_key key;
2712         struct old_sa_defrag_extent *old;
2713         struct new_sa_defrag_extent *new;
2714         int ret;
2715
2716         new = kmalloc(sizeof(*new), GFP_NOFS);
2717         if (!new)
2718                 return NULL;
2719
2720         new->inode = inode;
2721         new->file_pos = ordered->file_offset;
2722         new->len = ordered->len;
2723         new->bytenr = ordered->start;
2724         new->disk_len = ordered->disk_len;
2725         new->compress_type = ordered->compress_type;
2726         new->root = RB_ROOT;
2727         INIT_LIST_HEAD(&new->head);
2728
2729         path = btrfs_alloc_path();
2730         if (!path)
2731                 goto out_kfree;
2732
2733         key.objectid = btrfs_ino(inode);
2734         key.type = BTRFS_EXTENT_DATA_KEY;
2735         key.offset = new->file_pos;
2736
2737         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2738         if (ret < 0)
2739                 goto out_free_path;
2740         if (ret > 0 && path->slots[0] > 0)
2741                 path->slots[0]--;
2742
2743         /* find out all the old extents for the file range */
2744         while (1) {
2745                 struct btrfs_file_extent_item *extent;
2746                 struct extent_buffer *l;
2747                 int slot;
2748                 u64 num_bytes;
2749                 u64 offset;
2750                 u64 end;
2751                 u64 disk_bytenr;
2752                 u64 extent_offset;
2753
2754                 l = path->nodes[0];
2755                 slot = path->slots[0];
2756
2757                 if (slot >= btrfs_header_nritems(l)) {
2758                         ret = btrfs_next_leaf(root, path);
2759                         if (ret < 0)
2760                                 goto out_free_path;
2761                         else if (ret > 0)
2762                                 break;
2763                         continue;
2764                 }
2765
2766                 btrfs_item_key_to_cpu(l, &key, slot);
2767
2768                 if (key.objectid != btrfs_ino(inode))
2769                         break;
2770                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2771                         break;
2772                 if (key.offset >= new->file_pos + new->len)
2773                         break;
2774
2775                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2776
2777                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2778                 if (key.offset + num_bytes < new->file_pos)
2779                         goto next;
2780
2781                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2782                 if (!disk_bytenr)
2783                         goto next;
2784
2785                 extent_offset = btrfs_file_extent_offset(l, extent);
2786
2787                 old = kmalloc(sizeof(*old), GFP_NOFS);
2788                 if (!old)
2789                         goto out_free_path;
2790
2791                 offset = max(new->file_pos, key.offset);
2792                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2793
2794                 old->bytenr = disk_bytenr;
2795                 old->extent_offset = extent_offset;
2796                 old->offset = offset - key.offset;
2797                 old->len = end - offset;
2798                 old->new = new;
2799                 old->count = 0;
2800                 list_add_tail(&old->list, &new->head);
2801 next:
2802                 path->slots[0]++;
2803                 cond_resched();
2804         }
2805
2806         btrfs_free_path(path);
2807         atomic_inc(&root->fs_info->defrag_running);
2808
2809         return new;
2810
2811 out_free_path:
2812         btrfs_free_path(path);
2813 out_kfree:
2814         free_sa_defrag_extent(new);
2815         return NULL;
2816 }
2817
2818 static void btrfs_release_delalloc_bytes(struct btrfs_root *root,
2819                                          u64 start, u64 len)
2820 {
2821         struct btrfs_block_group_cache *cache;
2822
2823         cache = btrfs_lookup_block_group(root->fs_info, start);
2824         ASSERT(cache);
2825
2826         spin_lock(&cache->lock);
2827         cache->delalloc_bytes -= len;
2828         spin_unlock(&cache->lock);
2829
2830         btrfs_put_block_group(cache);
2831 }
2832
2833 /* as ordered data IO finishes, this gets called so we can finish
2834  * an ordered extent if the range of bytes in the file it covers are
2835  * fully written.
2836  */
2837 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2838 {
2839         struct inode *inode = ordered_extent->inode;
2840         struct btrfs_root *root = BTRFS_I(inode)->root;
2841         struct btrfs_trans_handle *trans = NULL;
2842         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2843         struct extent_state *cached_state = NULL;
2844         struct new_sa_defrag_extent *new = NULL;
2845         int compress_type = 0;
2846         int ret = 0;
2847         u64 logical_len = ordered_extent->len;
2848         bool nolock;
2849         bool truncated = false;
2850
2851         nolock = btrfs_is_free_space_inode(inode);
2852
2853         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2854                 ret = -EIO;
2855                 goto out;
2856         }
2857
2858         btrfs_free_io_failure_record(inode, ordered_extent->file_offset,
2859                                      ordered_extent->file_offset +
2860                                      ordered_extent->len - 1);
2861
2862         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2863                 truncated = true;
2864                 logical_len = ordered_extent->truncated_len;
2865                 /* Truncated the entire extent, don't bother adding */
2866                 if (!logical_len)
2867                         goto out;
2868         }
2869
2870         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2871                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2872
2873                 /*
2874                  * For mwrite(mmap + memset to write) case, we still reserve
2875                  * space for NOCOW range.
2876                  * As NOCOW won't cause a new delayed ref, just free the space
2877                  */
2878                 btrfs_qgroup_free_data(inode, ordered_extent->file_offset,
2879                                        ordered_extent->len);
2880                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2881                 if (nolock)
2882                         trans = btrfs_join_transaction_nolock(root);
2883                 else
2884                         trans = btrfs_join_transaction(root);
2885                 if (IS_ERR(trans)) {
2886                         ret = PTR_ERR(trans);
2887                         trans = NULL;
2888                         goto out;
2889                 }
2890                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2891                 ret = btrfs_update_inode_fallback(trans, root, inode);
2892                 if (ret) /* -ENOMEM or corruption */
2893                         btrfs_abort_transaction(trans, root, ret);
2894                 goto out;
2895         }
2896
2897         lock_extent_bits(io_tree, ordered_extent->file_offset,
2898                          ordered_extent->file_offset + ordered_extent->len - 1,
2899                          &cached_state);
2900
2901         ret = test_range_bit(io_tree, ordered_extent->file_offset,
2902                         ordered_extent->file_offset + ordered_extent->len - 1,
2903                         EXTENT_DEFRAG, 1, cached_state);
2904         if (ret) {
2905                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2906                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
2907                         /* the inode is shared */
2908                         new = record_old_file_extents(inode, ordered_extent);
2909
2910                 clear_extent_bit(io_tree, ordered_extent->file_offset,
2911                         ordered_extent->file_offset + ordered_extent->len - 1,
2912                         EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS);
2913         }
2914
2915         if (nolock)
2916                 trans = btrfs_join_transaction_nolock(root);
2917         else
2918                 trans = btrfs_join_transaction(root);
2919         if (IS_ERR(trans)) {
2920                 ret = PTR_ERR(trans);
2921                 trans = NULL;
2922                 goto out_unlock;
2923         }
2924
2925         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2926
2927         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2928                 compress_type = ordered_extent->compress_type;
2929         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2930                 BUG_ON(compress_type);
2931                 ret = btrfs_mark_extent_written(trans, inode,
2932                                                 ordered_extent->file_offset,
2933                                                 ordered_extent->file_offset +
2934                                                 logical_len);
2935         } else {
2936                 BUG_ON(root == root->fs_info->tree_root);
2937                 ret = insert_reserved_file_extent(trans, inode,
2938                                                 ordered_extent->file_offset,
2939                                                 ordered_extent->start,
2940                                                 ordered_extent->disk_len,
2941                                                 logical_len, logical_len,
2942                                                 compress_type, 0, 0,
2943                                                 BTRFS_FILE_EXTENT_REG);
2944                 if (!ret)
2945                         btrfs_release_delalloc_bytes(root,
2946                                                      ordered_extent->start,
2947                                                      ordered_extent->disk_len);
2948         }
2949         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2950                            ordered_extent->file_offset, ordered_extent->len,
2951                            trans->transid);
2952         if (ret < 0) {
2953                 btrfs_abort_transaction(trans, root, ret);
2954                 goto out_unlock;
2955         }
2956
2957         add_pending_csums(trans, inode, ordered_extent->file_offset,
2958                           &ordered_extent->list);
2959
2960         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2961         ret = btrfs_update_inode_fallback(trans, root, inode);
2962         if (ret) { /* -ENOMEM or corruption */
2963                 btrfs_abort_transaction(trans, root, ret);
2964                 goto out_unlock;
2965         }
2966         ret = 0;
2967 out_unlock:
2968         unlock_extent_cached(io_tree, ordered_extent->file_offset,
2969                              ordered_extent->file_offset +
2970                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
2971 out:
2972         if (root != root->fs_info->tree_root)
2973                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
2974         if (trans)
2975                 btrfs_end_transaction(trans, root);
2976
2977         if (ret || truncated) {
2978                 u64 start, end;
2979
2980                 if (truncated)
2981                         start = ordered_extent->file_offset + logical_len;
2982                 else
2983                         start = ordered_extent->file_offset;
2984                 end = ordered_extent->file_offset + ordered_extent->len - 1;
2985                 clear_extent_uptodate(io_tree, start, end, NULL, GFP_NOFS);
2986
2987                 /* Drop the cache for the part of the extent we didn't write. */
2988                 btrfs_drop_extent_cache(inode, start, end, 0);
2989
2990                 /*
2991                  * If the ordered extent had an IOERR or something else went
2992                  * wrong we need to return the space for this ordered extent
2993                  * back to the allocator.  We only free the extent in the
2994                  * truncated case if we didn't write out the extent at all.
2995                  */
2996                 if ((ret || !logical_len) &&
2997                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2998                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
2999                         btrfs_free_reserved_extent(root, ordered_extent->start,
3000                                                    ordered_extent->disk_len, 1);
3001         }
3002
3003
3004         /*
3005          * This needs to be done to make sure anybody waiting knows we are done
3006          * updating everything for this ordered extent.
3007          */
3008         btrfs_remove_ordered_extent(inode, ordered_extent);
3009
3010         /* for snapshot-aware defrag */
3011         if (new) {
3012                 if (ret) {
3013                         free_sa_defrag_extent(new);
3014                         atomic_dec(&root->fs_info->defrag_running);
3015                 } else {
3016                         relink_file_extents(new);
3017                 }
3018         }
3019
3020         /* once for us */
3021         btrfs_put_ordered_extent(ordered_extent);
3022         /* once for the tree */
3023         btrfs_put_ordered_extent(ordered_extent);
3024
3025         return ret;
3026 }
3027
3028 static void finish_ordered_fn(struct btrfs_work *work)
3029 {
3030         struct btrfs_ordered_extent *ordered_extent;
3031         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
3032         btrfs_finish_ordered_io(ordered_extent);
3033 }
3034
3035 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
3036                                 struct extent_state *state, int uptodate)
3037 {
3038         struct inode *inode = page->mapping->host;
3039         struct btrfs_root *root = BTRFS_I(inode)->root;
3040         struct btrfs_ordered_extent *ordered_extent = NULL;
3041         struct btrfs_workqueue *wq;
3042         btrfs_work_func_t func;
3043
3044         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
3045
3046         ClearPagePrivate2(page);
3047         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
3048                                             end - start + 1, uptodate))
3049                 return 0;
3050
3051         if (btrfs_is_free_space_inode(inode)) {
3052                 wq = root->fs_info->endio_freespace_worker;
3053                 func = btrfs_freespace_write_helper;
3054         } else {
3055                 wq = root->fs_info->endio_write_workers;
3056                 func = btrfs_endio_write_helper;
3057         }
3058
3059         btrfs_init_work(&ordered_extent->work, func, finish_ordered_fn, NULL,
3060                         NULL);
3061         btrfs_queue_work(wq, &ordered_extent->work);
3062
3063         return 0;
3064 }
3065
3066 static int __readpage_endio_check(struct inode *inode,
3067                                   struct btrfs_io_bio *io_bio,
3068                                   int icsum, struct page *page,
3069                                   int pgoff, u64 start, size_t len)
3070 {
3071         char *kaddr;
3072         u32 csum_expected;
3073         u32 csum = ~(u32)0;
3074
3075         csum_expected = *(((u32 *)io_bio->csum) + icsum);
3076
3077         kaddr = kmap_atomic(page);
3078         csum = btrfs_csum_data(kaddr + pgoff, csum,  len);
3079         btrfs_csum_final(csum, (char *)&csum);
3080         if (csum != csum_expected)
3081                 goto zeroit;
3082
3083         kunmap_atomic(kaddr);
3084         return 0;
3085 zeroit:
3086         btrfs_warn_rl(BTRFS_I(inode)->root->fs_info,
3087                 "csum failed ino %llu off %llu csum %u expected csum %u",
3088                            btrfs_ino(inode), start, csum, csum_expected);
3089         memset(kaddr + pgoff, 1, len);
3090         flush_dcache_page(page);
3091         kunmap_atomic(kaddr);
3092         if (csum_expected == 0)
3093                 return 0;
3094         return -EIO;
3095 }
3096
3097 /*
3098  * when reads are done, we need to check csums to verify the data is correct
3099  * if there's a match, we allow the bio to finish.  If not, the code in
3100  * extent_io.c will try to find good copies for us.
3101  */
3102 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
3103                                       u64 phy_offset, struct page *page,
3104                                       u64 start, u64 end, int mirror)
3105 {
3106         size_t offset = start - page_offset(page);
3107         struct inode *inode = page->mapping->host;
3108         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3109         struct btrfs_root *root = BTRFS_I(inode)->root;
3110
3111         if (PageChecked(page)) {
3112                 ClearPageChecked(page);
3113                 return 0;
3114         }
3115
3116         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
3117                 return 0;
3118
3119         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
3120             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
3121                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM);
3122                 return 0;
3123         }
3124
3125         phy_offset >>= inode->i_sb->s_blocksize_bits;
3126         return __readpage_endio_check(inode, io_bio, phy_offset, page, offset,
3127                                       start, (size_t)(end - start + 1));
3128 }
3129
3130 void btrfs_add_delayed_iput(struct inode *inode)
3131 {
3132         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
3133         struct btrfs_inode *binode = BTRFS_I(inode);
3134
3135         if (atomic_add_unless(&inode->i_count, -1, 1))
3136                 return;
3137
3138         spin_lock(&fs_info->delayed_iput_lock);
3139         if (binode->delayed_iput_count == 0) {
3140                 ASSERT(list_empty(&binode->delayed_iput));
3141                 list_add_tail(&binode->delayed_iput, &fs_info->delayed_iputs);
3142         } else {
3143                 binode->delayed_iput_count++;
3144         }
3145         spin_unlock(&fs_info->delayed_iput_lock);
3146 }
3147
3148 void btrfs_run_delayed_iputs(struct btrfs_root *root)
3149 {
3150         struct btrfs_fs_info *fs_info = root->fs_info;
3151
3152         spin_lock(&fs_info->delayed_iput_lock);
3153         while (!list_empty(&fs_info->delayed_iputs)) {
3154                 struct btrfs_inode *inode;
3155
3156                 inode = list_first_entry(&fs_info->delayed_iputs,
3157                                 struct btrfs_inode, delayed_iput);
3158                 if (inode->delayed_iput_count) {
3159                         inode->delayed_iput_count--;
3160                         list_move_tail(&inode->delayed_iput,
3161                                         &fs_info->delayed_iputs);
3162                 } else {
3163                         list_del_init(&inode->delayed_iput);
3164                 }
3165                 spin_unlock(&fs_info->delayed_iput_lock);
3166                 iput(&inode->vfs_inode);
3167                 spin_lock(&fs_info->delayed_iput_lock);
3168         }
3169         spin_unlock(&fs_info->delayed_iput_lock);
3170 }
3171
3172 /*
3173  * This is called in transaction commit time. If there are no orphan
3174  * files in the subvolume, it removes orphan item and frees block_rsv
3175  * structure.
3176  */
3177 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
3178                               struct btrfs_root *root)
3179 {
3180         struct btrfs_block_rsv *block_rsv;
3181         int ret;
3182
3183         if (atomic_read(&root->orphan_inodes) ||
3184             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
3185                 return;
3186
3187         spin_lock(&root->orphan_lock);
3188         if (atomic_read(&root->orphan_inodes)) {
3189                 spin_unlock(&root->orphan_lock);
3190                 return;
3191         }
3192
3193         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
3194                 spin_unlock(&root->orphan_lock);
3195                 return;
3196         }
3197
3198         block_rsv = root->orphan_block_rsv;
3199         root->orphan_block_rsv = NULL;
3200         spin_unlock(&root->orphan_lock);
3201
3202         if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state) &&
3203             btrfs_root_refs(&root->root_item) > 0) {
3204                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
3205                                             root->root_key.objectid);
3206                 if (ret)
3207                         btrfs_abort_transaction(trans, root, ret);
3208                 else
3209                         clear_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
3210                                   &root->state);
3211         }
3212
3213         if (block_rsv) {
3214                 WARN_ON(block_rsv->size > 0);
3215                 btrfs_free_block_rsv(root, block_rsv);
3216         }
3217 }
3218
3219 /*
3220  * This creates an orphan entry for the given inode in case something goes
3221  * wrong in the middle of an unlink/truncate.
3222  *
3223  * NOTE: caller of this function should reserve 5 units of metadata for
3224  *       this function.
3225  */
3226 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
3227 {
3228         struct btrfs_root *root = BTRFS_I(inode)->root;
3229         struct btrfs_block_rsv *block_rsv = NULL;
3230         int reserve = 0;
3231         int insert = 0;
3232         int ret;
3233
3234         if (!root->orphan_block_rsv) {
3235                 block_rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
3236                 if (!block_rsv)
3237                         return -ENOMEM;
3238         }
3239
3240         spin_lock(&root->orphan_lock);
3241         if (!root->orphan_block_rsv) {
3242                 root->orphan_block_rsv = block_rsv;
3243         } else if (block_rsv) {
3244                 btrfs_free_block_rsv(root, block_rsv);
3245                 block_rsv = NULL;
3246         }
3247
3248         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3249                               &BTRFS_I(inode)->runtime_flags)) {
3250 #if 0
3251                 /*
3252                  * For proper ENOSPC handling, we should do orphan
3253                  * cleanup when mounting. But this introduces backward
3254                  * compatibility issue.
3255                  */
3256                 if (!xchg(&root->orphan_item_inserted, 1))
3257                         insert = 2;
3258                 else
3259                         insert = 1;
3260 #endif
3261                 insert = 1;
3262                 atomic_inc(&root->orphan_inodes);
3263         }
3264
3265         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3266                               &BTRFS_I(inode)->runtime_flags))
3267                 reserve = 1;
3268         spin_unlock(&root->orphan_lock);
3269
3270         /* grab metadata reservation from transaction handle */
3271         if (reserve) {
3272                 ret = btrfs_orphan_reserve_metadata(trans, inode);
3273                 ASSERT(!ret);
3274                 if (ret) {
3275                         atomic_dec(&root->orphan_inodes);
3276                         clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3277                                   &BTRFS_I(inode)->runtime_flags);
3278                         if (insert)
3279                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3280                                           &BTRFS_I(inode)->runtime_flags);
3281                         return ret;
3282                 }
3283         }
3284
3285         /* insert an orphan item to track this unlinked/truncated file */
3286         if (insert >= 1) {
3287                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
3288                 if (ret) {
3289                         atomic_dec(&root->orphan_inodes);
3290                         if (reserve) {
3291                                 clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3292                                           &BTRFS_I(inode)->runtime_flags);
3293                                 btrfs_orphan_release_metadata(inode);
3294                         }
3295                         if (ret != -EEXIST) {
3296                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3297                                           &BTRFS_I(inode)->runtime_flags);
3298                                 btrfs_abort_transaction(trans, root, ret);
3299                                 return ret;
3300                         }
3301                 }
3302                 ret = 0;
3303         }
3304
3305         /* insert an orphan item to track subvolume contains orphan files */
3306         if (insert >= 2) {
3307                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
3308                                                root->root_key.objectid);
3309                 if (ret && ret != -EEXIST) {
3310                         btrfs_abort_transaction(trans, root, ret);
3311                         return ret;
3312                 }
3313         }
3314         return 0;
3315 }
3316
3317 /*
3318  * We have done the truncate/delete so we can go ahead and remove the orphan
3319  * item for this particular inode.
3320  */
3321 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3322                             struct inode *inode)
3323 {
3324         struct btrfs_root *root = BTRFS_I(inode)->root;
3325         int delete_item = 0;
3326         int release_rsv = 0;
3327         int ret = 0;
3328
3329         spin_lock(&root->orphan_lock);
3330         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3331                                &BTRFS_I(inode)->runtime_flags))
3332                 delete_item = 1;
3333
3334         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3335                                &BTRFS_I(inode)->runtime_flags))
3336                 release_rsv = 1;
3337         spin_unlock(&root->orphan_lock);
3338
3339         if (delete_item) {
3340                 atomic_dec(&root->orphan_inodes);
3341                 if (trans)
3342                         ret = btrfs_del_orphan_item(trans, root,
3343                                                     btrfs_ino(inode));
3344         }
3345
3346         if (release_rsv)
3347                 btrfs_orphan_release_metadata(inode);
3348
3349         return ret;
3350 }
3351
3352 /*
3353  * this cleans up any orphans that may be left on the list from the last use
3354  * of this root.
3355  */
3356 int btrfs_orphan_cleanup(struct btrfs_root *root)
3357 {
3358         struct btrfs_path *path;
3359         struct extent_buffer *leaf;
3360         struct btrfs_key key, found_key;
3361         struct btrfs_trans_handle *trans;
3362         struct inode *inode;
3363         u64 last_objectid = 0;
3364         int ret = 0, nr_unlink = 0, nr_truncate = 0;
3365
3366         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3367                 return 0;
3368
3369         path = btrfs_alloc_path();
3370         if (!path) {
3371                 ret = -ENOMEM;
3372                 goto out;
3373         }
3374         path->reada = READA_BACK;
3375
3376         key.objectid = BTRFS_ORPHAN_OBJECTID;
3377         key.type = BTRFS_ORPHAN_ITEM_KEY;
3378         key.offset = (u64)-1;
3379
3380         while (1) {
3381                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3382                 if (ret < 0)
3383                         goto out;
3384
3385                 /*
3386                  * if ret == 0 means we found what we were searching for, which
3387                  * is weird, but possible, so only screw with path if we didn't
3388                  * find the key and see if we have stuff that matches
3389                  */
3390                 if (ret > 0) {
3391                         ret = 0;
3392                         if (path->slots[0] == 0)
3393                                 break;
3394                         path->slots[0]--;
3395                 }
3396
3397                 /* pull out the item */
3398                 leaf = path->nodes[0];
3399                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3400
3401                 /* make sure the item matches what we want */
3402                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3403                         break;
3404                 if (found_key.type != BTRFS_ORPHAN_ITEM_KEY)
3405                         break;
3406
3407                 /* release the path since we're done with it */
3408                 btrfs_release_path(path);
3409
3410                 /*
3411                  * this is where we are basically btrfs_lookup, without the
3412                  * crossing root thing.  we store the inode number in the
3413                  * offset of the orphan item.
3414                  */
3415
3416                 if (found_key.offset == last_objectid) {
3417                         btrfs_err(root->fs_info,
3418                                 "Error removing orphan entry, stopping orphan cleanup");
3419                         ret = -EINVAL;
3420                         goto out;
3421                 }
3422
3423                 last_objectid = found_key.offset;
3424
3425                 found_key.objectid = found_key.offset;
3426                 found_key.type = BTRFS_INODE_ITEM_KEY;
3427                 found_key.offset = 0;
3428                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
3429                 ret = PTR_ERR_OR_ZERO(inode);
3430                 if (ret && ret != -ESTALE)
3431                         goto out;
3432
3433                 if (ret == -ESTALE && root == root->fs_info->tree_root) {
3434                         struct btrfs_root *dead_root;
3435                         struct btrfs_fs_info *fs_info = root->fs_info;
3436                         int is_dead_root = 0;
3437
3438                         /*
3439                          * this is an orphan in the tree root. Currently these
3440                          * could come from 2 sources:
3441                          *  a) a snapshot deletion in progress
3442                          *  b) a free space cache inode
3443                          * We need to distinguish those two, as the snapshot
3444                          * orphan must not get deleted.
3445                          * find_dead_roots already ran before us, so if this
3446                          * is a snapshot deletion, we should find the root
3447                          * in the dead_roots list
3448                          */
3449                         spin_lock(&fs_info->trans_lock);
3450                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3451                                             root_list) {
3452                                 if (dead_root->root_key.objectid ==
3453                                     found_key.objectid) {
3454                                         is_dead_root = 1;
3455                                         break;
3456                                 }
3457                         }
3458                         spin_unlock(&fs_info->trans_lock);
3459                         if (is_dead_root) {
3460                                 /* prevent this orphan from being found again */
3461                                 key.offset = found_key.objectid - 1;
3462                                 continue;
3463                         }
3464                 }
3465                 /*
3466                  * Inode is already gone but the orphan item is still there,
3467                  * kill the orphan item.
3468                  */
3469                 if (ret == -ESTALE) {
3470                         trans = btrfs_start_transaction(root, 1);
3471                         if (IS_ERR(trans)) {
3472                                 ret = PTR_ERR(trans);
3473                                 goto out;
3474                         }
3475                         btrfs_debug(root->fs_info, "auto deleting %Lu",
3476                                 found_key.objectid);
3477                         ret = btrfs_del_orphan_item(trans, root,
3478                                                     found_key.objectid);
3479                         btrfs_end_transaction(trans, root);
3480                         if (ret)
3481                                 goto out;
3482                         continue;
3483                 }
3484
3485                 /*
3486                  * add this inode to the orphan list so btrfs_orphan_del does
3487                  * the proper thing when we hit it
3488                  */
3489                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3490                         &BTRFS_I(inode)->runtime_flags);
3491                 atomic_inc(&root->orphan_inodes);
3492
3493                 /* if we have links, this was a truncate, lets do that */
3494                 if (inode->i_nlink) {
3495                         if (WARN_ON(!S_ISREG(inode->i_mode))) {
3496                                 iput(inode);
3497                                 continue;
3498                         }
3499                         nr_truncate++;
3500
3501                         /* 1 for the orphan item deletion. */
3502                         trans = btrfs_start_transaction(root, 1);
3503                         if (IS_ERR(trans)) {
3504                                 iput(inode);
3505                                 ret = PTR_ERR(trans);
3506                                 goto out;
3507                         }
3508                         ret = btrfs_orphan_add(trans, inode);
3509                         btrfs_end_transaction(trans, root);
3510                         if (ret) {
3511                                 iput(inode);
3512                                 goto out;
3513                         }
3514
3515                         ret = btrfs_truncate(inode);
3516                         if (ret)
3517                                 btrfs_orphan_del(NULL, inode);
3518                 } else {
3519                         nr_unlink++;
3520                 }
3521
3522                 /* this will do delete_inode and everything for us */
3523                 iput(inode);
3524                 if (ret)
3525                         goto out;
3526         }
3527         /* release the path since we're done with it */
3528         btrfs_release_path(path);
3529
3530         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3531
3532         if (root->orphan_block_rsv)
3533                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
3534                                         (u64)-1);
3535
3536         if (root->orphan_block_rsv ||
3537             test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
3538                 trans = btrfs_join_transaction(root);
3539                 if (!IS_ERR(trans))
3540                         btrfs_end_transaction(trans, root);
3541         }
3542
3543         if (nr_unlink)
3544                 btrfs_debug(root->fs_info, "unlinked %d orphans", nr_unlink);
3545         if (nr_truncate)
3546                 btrfs_debug(root->fs_info, "truncated %d orphans", nr_truncate);
3547
3548 out:
3549         if (ret)
3550                 btrfs_err(root->fs_info,
3551                         "could not do orphan cleanup %d", ret);
3552         btrfs_free_path(path);
3553         return ret;
3554 }
3555
3556 /*
3557  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3558  * don't find any xattrs, we know there can't be any acls.
3559  *
3560  * slot is the slot the inode is in, objectid is the objectid of the inode
3561  */
3562 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3563                                           int slot, u64 objectid,
3564                                           int *first_xattr_slot)
3565 {
3566         u32 nritems = btrfs_header_nritems(leaf);
3567         struct btrfs_key found_key;
3568         static u64 xattr_access = 0;
3569         static u64 xattr_default = 0;
3570         int scanned = 0;
3571
3572         if (!xattr_access) {
3573                 xattr_access = btrfs_name_hash(XATTR_NAME_POSIX_ACL_ACCESS,
3574                                         strlen(XATTR_NAME_POSIX_ACL_ACCESS));
3575                 xattr_default = btrfs_name_hash(XATTR_NAME_POSIX_ACL_DEFAULT,
3576                                         strlen(XATTR_NAME_POSIX_ACL_DEFAULT));
3577         }
3578
3579         slot++;
3580         *first_xattr_slot = -1;
3581         while (slot < nritems) {
3582                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3583
3584                 /* we found a different objectid, there must not be acls */
3585                 if (found_key.objectid != objectid)
3586                         return 0;
3587
3588                 /* we found an xattr, assume we've got an acl */
3589                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3590                         if (*first_xattr_slot == -1)
3591                                 *first_xattr_slot = slot;
3592                         if (found_key.offset == xattr_access ||
3593                             found_key.offset == xattr_default)
3594                                 return 1;
3595                 }
3596
3597                 /*
3598                  * we found a key greater than an xattr key, there can't
3599                  * be any acls later on
3600                  */
3601                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3602                         return 0;
3603
3604                 slot++;
3605                 scanned++;
3606
3607                 /*
3608                  * it goes inode, inode backrefs, xattrs, extents,
3609                  * so if there are a ton of hard links to an inode there can
3610                  * be a lot of backrefs.  Don't waste time searching too hard,
3611                  * this is just an optimization
3612                  */
3613                 if (scanned >= 8)
3614                         break;
3615         }
3616         /* we hit the end of the leaf before we found an xattr or
3617          * something larger than an xattr.  We have to assume the inode
3618          * has acls
3619          */
3620         if (*first_xattr_slot == -1)
3621                 *first_xattr_slot = slot;
3622         return 1;
3623 }
3624
3625 /*
3626  * read an inode from the btree into the in-memory inode
3627  */
3628 static void btrfs_read_locked_inode(struct inode *inode)
3629 {
3630         struct btrfs_path *path;
3631         struct extent_buffer *leaf;
3632         struct btrfs_inode_item *inode_item;
3633         struct btrfs_root *root = BTRFS_I(inode)->root;
3634         struct btrfs_key location;
3635         unsigned long ptr;
3636         int maybe_acls;
3637         u32 rdev;
3638         int ret;
3639         bool filled = false;
3640         int first_xattr_slot;
3641
3642         ret = btrfs_fill_inode(inode, &rdev);
3643         if (!ret)
3644                 filled = true;
3645
3646         path = btrfs_alloc_path();
3647         if (!path)
3648                 goto make_bad;
3649
3650         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3651
3652         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3653         if (ret)
3654                 goto make_bad;
3655
3656         leaf = path->nodes[0];
3657
3658         if (filled)
3659                 goto cache_index;
3660
3661         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3662                                     struct btrfs_inode_item);
3663         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3664         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3665         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3666         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3667         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
3668
3669         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->atime);
3670         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->atime);
3671
3672         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->mtime);
3673         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->mtime);
3674
3675         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->ctime);
3676         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->ctime);
3677
3678         BTRFS_I(inode)->i_otime.tv_sec =
3679                 btrfs_timespec_sec(leaf, &inode_item->otime);
3680         BTRFS_I(inode)->i_otime.tv_nsec =
3681                 btrfs_timespec_nsec(leaf, &inode_item->otime);
3682
3683         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3684         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3685         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3686
3687         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
3688         inode->i_generation = BTRFS_I(inode)->generation;
3689         inode->i_rdev = 0;
3690         rdev = btrfs_inode_rdev(leaf, inode_item);
3691
3692         BTRFS_I(inode)->index_cnt = (u64)-1;
3693         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3694
3695 cache_index:
3696         /*
3697          * If we were modified in the current generation and evicted from memory
3698          * and then re-read we need to do a full sync since we don't have any
3699          * idea about which extents were modified before we were evicted from
3700          * cache.
3701          *
3702          * This is required for both inode re-read from disk and delayed inode
3703          * in delayed_nodes_tree.
3704          */
3705         if (BTRFS_I(inode)->last_trans == root->fs_info->generation)
3706                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3707                         &BTRFS_I(inode)->runtime_flags);
3708
3709         /*
3710          * We don't persist the id of the transaction where an unlink operation
3711          * against the inode was last made. So here we assume the inode might
3712          * have been evicted, and therefore the exact value of last_unlink_trans
3713          * lost, and set it to last_trans to avoid metadata inconsistencies
3714          * between the inode and its parent if the inode is fsync'ed and the log
3715          * replayed. For example, in the scenario:
3716          *
3717          * touch mydir/foo
3718          * ln mydir/foo mydir/bar
3719          * sync
3720          * unlink mydir/bar
3721          * echo 2 > /proc/sys/vm/drop_caches   # evicts inode
3722          * xfs_io -c fsync mydir/foo
3723          * <power failure>
3724          * mount fs, triggers fsync log replay
3725          *
3726          * We must make sure that when we fsync our inode foo we also log its
3727          * parent inode, otherwise after log replay the parent still has the
3728          * dentry with the "bar" name but our inode foo has a link count of 1
3729          * and doesn't have an inode ref with the name "bar" anymore.
3730          *
3731          * Setting last_unlink_trans to last_trans is a pessimistic approach,
3732          * but it guarantees correctness at the expense of occasional full
3733          * transaction commits on fsync if our inode is a directory, or if our
3734          * inode is not a directory, logging its parent unnecessarily.
3735          */
3736         BTRFS_I(inode)->last_unlink_trans = BTRFS_I(inode)->last_trans;
3737
3738         path->slots[0]++;
3739         if (inode->i_nlink != 1 ||
3740             path->slots[0] >= btrfs_header_nritems(leaf))
3741                 goto cache_acl;
3742
3743         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3744         if (location.objectid != btrfs_ino(inode))
3745                 goto cache_acl;
3746
3747         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3748         if (location.type == BTRFS_INODE_REF_KEY) {
3749                 struct btrfs_inode_ref *ref;
3750
3751                 ref = (struct btrfs_inode_ref *)ptr;
3752                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3753         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3754                 struct btrfs_inode_extref *extref;
3755
3756                 extref = (struct btrfs_inode_extref *)ptr;
3757                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3758                                                                      extref);
3759         }
3760 cache_acl:
3761         /*
3762          * try to precache a NULL acl entry for files that don't have
3763          * any xattrs or acls
3764          */
3765         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3766                                            btrfs_ino(inode), &first_xattr_slot);
3767         if (first_xattr_slot != -1) {
3768                 path->slots[0] = first_xattr_slot;
3769                 ret = btrfs_load_inode_props(inode, path);
3770                 if (ret)
3771                         btrfs_err(root->fs_info,
3772                                   "error loading props for ino %llu (root %llu): %d",
3773                                   btrfs_ino(inode),
3774                                   root->root_key.objectid, ret);
3775         }
3776         btrfs_free_path(path);
3777
3778         if (!maybe_acls)
3779                 cache_no_acl(inode);
3780
3781         switch (inode->i_mode & S_IFMT) {
3782         case S_IFREG:
3783                 inode->i_mapping->a_ops = &btrfs_aops;
3784                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3785                 inode->i_fop = &btrfs_file_operations;
3786                 inode->i_op = &btrfs_file_inode_operations;
3787                 break;
3788         case S_IFDIR:
3789                 inode->i_fop = &btrfs_dir_file_operations;
3790                 if (root == root->fs_info->tree_root)
3791                         inode->i_op = &btrfs_dir_ro_inode_operations;
3792                 else
3793                         inode->i_op = &btrfs_dir_inode_operations;
3794                 break;
3795         case S_IFLNK:
3796                 inode->i_op = &btrfs_symlink_inode_operations;
3797                 inode_nohighmem(inode);
3798                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3799                 break;
3800         default:
3801                 inode->i_op = &btrfs_special_inode_operations;
3802                 init_special_inode(inode, inode->i_mode, rdev);
3803                 break;
3804         }
3805
3806         btrfs_update_iflags(inode);
3807         return;
3808
3809 make_bad:
3810         btrfs_free_path(path);
3811         make_bad_inode(inode);
3812 }
3813
3814 /*
3815  * given a leaf and an inode, copy the inode fields into the leaf
3816  */
3817 static void fill_inode_item(struct btrfs_trans_handle *trans,
3818                             struct extent_buffer *leaf,
3819                             struct btrfs_inode_item *item,
3820                             struct inode *inode)
3821 {
3822         struct btrfs_map_token token;
3823
3824         btrfs_init_map_token(&token);
3825
3826         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3827         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3828         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3829                                    &token);
3830         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3831         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3832
3833         btrfs_set_token_timespec_sec(leaf, &item->atime,
3834                                      inode->i_atime.tv_sec, &token);
3835         btrfs_set_token_timespec_nsec(leaf, &item->atime,
3836                                       inode->i_atime.tv_nsec, &token);
3837
3838         btrfs_set_token_timespec_sec(leaf, &item->mtime,
3839                                      inode->i_mtime.tv_sec, &token);
3840         btrfs_set_token_timespec_nsec(leaf, &item->mtime,
3841                                       inode->i_mtime.tv_nsec, &token);
3842
3843         btrfs_set_token_timespec_sec(leaf, &item->ctime,
3844                                      inode->i_ctime.tv_sec, &token);
3845         btrfs_set_token_timespec_nsec(leaf, &item->ctime,
3846                                       inode->i_ctime.tv_nsec, &token);
3847
3848         btrfs_set_token_timespec_sec(leaf, &item->otime,
3849                                      BTRFS_I(inode)->i_otime.tv_sec, &token);
3850         btrfs_set_token_timespec_nsec(leaf, &item->otime,
3851                                       BTRFS_I(inode)->i_otime.tv_nsec, &token);
3852
3853         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3854                                      &token);
3855         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3856                                          &token);
3857         btrfs_set_token_inode_sequence(leaf, item, inode->i_version, &token);
3858         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3859         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3860         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3861         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3862 }
3863
3864 /*
3865  * copy everything in the in-memory inode into the btree.
3866  */
3867 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3868                                 struct btrfs_root *root, struct inode *inode)
3869 {
3870         struct btrfs_inode_item *inode_item;
3871         struct btrfs_path *path;
3872         struct extent_buffer *leaf;
3873         int ret;
3874
3875         path = btrfs_alloc_path();
3876         if (!path)
3877                 return -ENOMEM;
3878
3879         path->leave_spinning = 1;
3880         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3881                                  1);
3882         if (ret) {
3883                 if (ret > 0)
3884                         ret = -ENOENT;
3885                 goto failed;
3886         }
3887
3888         leaf = path->nodes[0];
3889         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3890                                     struct btrfs_inode_item);
3891
3892         fill_inode_item(trans, leaf, inode_item, inode);
3893         btrfs_mark_buffer_dirty(leaf);
3894         btrfs_set_inode_last_trans(trans, inode);
3895         ret = 0;
3896 failed:
3897         btrfs_free_path(path);
3898         return ret;
3899 }
3900
3901 /*
3902  * copy everything in the in-memory inode into the btree.
3903  */
3904 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3905                                 struct btrfs_root *root, struct inode *inode)
3906 {
3907         int ret;
3908
3909         /*
3910          * If the inode is a free space inode, we can deadlock during commit
3911          * if we put it into the delayed code.
3912          *
3913          * The data relocation inode should also be directly updated
3914          * without delay
3915          */
3916         if (!btrfs_is_free_space_inode(inode)
3917             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
3918             && !root->fs_info->log_root_recovering) {
3919                 btrfs_update_root_times(trans, root);
3920
3921                 ret = btrfs_delayed_update_inode(trans, root, inode);
3922                 if (!ret)
3923                         btrfs_set_inode_last_trans(trans, inode);
3924                 return ret;
3925         }
3926
3927         return btrfs_update_inode_item(trans, root, inode);
3928 }
3929
3930 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3931                                          struct btrfs_root *root,
3932                                          struct inode *inode)
3933 {
3934         int ret;
3935
3936         ret = btrfs_update_inode(trans, root, inode);
3937         if (ret == -ENOSPC)
3938                 return btrfs_update_inode_item(trans, root, inode);
3939         return ret;
3940 }
3941
3942 /*
3943  * unlink helper that gets used here in inode.c and in the tree logging
3944  * recovery code.  It remove a link in a directory with a given name, and
3945  * also drops the back refs in the inode to the directory
3946  */
3947 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3948                                 struct btrfs_root *root,
3949                                 struct inode *dir, struct inode *inode,
3950                                 const char *name, int name_len)
3951 {
3952         struct btrfs_path *path;
3953         int ret = 0;
3954         struct extent_buffer *leaf;
3955         struct btrfs_dir_item *di;
3956         struct btrfs_key key;
3957         u64 index;
3958         u64 ino = btrfs_ino(inode);
3959         u64 dir_ino = btrfs_ino(dir);
3960
3961         path = btrfs_alloc_path();
3962         if (!path) {
3963                 ret = -ENOMEM;
3964                 goto out;
3965         }
3966
3967         path->leave_spinning = 1;
3968         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3969                                     name, name_len, -1);
3970         if (IS_ERR(di)) {
3971                 ret = PTR_ERR(di);
3972                 goto err;
3973         }
3974         if (!di) {
3975                 ret = -ENOENT;
3976                 goto err;
3977         }
3978         leaf = path->nodes[0];
3979         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3980         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3981         if (ret)
3982                 goto err;
3983         btrfs_release_path(path);
3984
3985         /*
3986          * If we don't have dir index, we have to get it by looking up
3987          * the inode ref, since we get the inode ref, remove it directly,
3988          * it is unnecessary to do delayed deletion.
3989          *
3990          * But if we have dir index, needn't search inode ref to get it.
3991          * Since the inode ref is close to the inode item, it is better
3992          * that we delay to delete it, and just do this deletion when
3993          * we update the inode item.
3994          */
3995         if (BTRFS_I(inode)->dir_index) {
3996                 ret = btrfs_delayed_delete_inode_ref(inode);
3997                 if (!ret) {
3998                         index = BTRFS_I(inode)->dir_index;
3999                         goto skip_backref;
4000                 }
4001         }
4002
4003         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
4004                                   dir_ino, &index);
4005         if (ret) {
4006                 btrfs_info(root->fs_info,
4007                         "failed to delete reference to %.*s, inode %llu parent %llu",
4008                         name_len, name, ino, dir_ino);
4009                 btrfs_abort_transaction(trans, root, ret);
4010                 goto err;
4011         }
4012 skip_backref:
4013         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
4014         if (ret) {
4015                 btrfs_abort_transaction(trans, root, ret);
4016                 goto err;
4017         }
4018
4019         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
4020                                          inode, dir_ino);
4021         if (ret != 0 && ret != -ENOENT) {
4022                 btrfs_abort_transaction(trans, root, ret);
4023                 goto err;
4024         }
4025
4026         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
4027                                            dir, index);
4028         if (ret == -ENOENT)
4029                 ret = 0;
4030         else if (ret)
4031                 btrfs_abort_transaction(trans, root, ret);
4032 err:
4033         btrfs_free_path(path);
4034         if (ret)
4035                 goto out;
4036
4037         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
4038         inode_inc_iversion(inode);
4039         inode_inc_iversion(dir);
4040         inode->i_ctime = dir->i_mtime =
4041                 dir->i_ctime = current_fs_time(inode->i_sb);
4042         ret = btrfs_update_inode(trans, root, dir);
4043 out:
4044         return ret;
4045 }
4046
4047 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
4048                        struct btrfs_root *root,
4049                        struct inode *dir, struct inode *inode,
4050                        const char *name, int name_len)
4051 {
4052         int ret;
4053         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
4054         if (!ret) {
4055                 drop_nlink(inode);
4056                 ret = btrfs_update_inode(trans, root, inode);
4057         }
4058         return ret;
4059 }
4060
4061 /*
4062  * helper to start transaction for unlink and rmdir.
4063  *
4064  * unlink and rmdir are special in btrfs, they do not always free space, so
4065  * if we cannot make our reservations the normal way try and see if there is
4066  * plenty of slack room in the global reserve to migrate, otherwise we cannot
4067  * allow the unlink to occur.
4068  */
4069 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
4070 {
4071         struct btrfs_root *root = BTRFS_I(dir)->root;
4072
4073         /*
4074          * 1 for the possible orphan item
4075          * 1 for the dir item
4076          * 1 for the dir index
4077          * 1 for the inode ref
4078          * 1 for the inode
4079          */
4080         return btrfs_start_transaction_fallback_global_rsv(root, 5, 5);
4081 }
4082
4083 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
4084 {
4085         struct btrfs_root *root = BTRFS_I(dir)->root;
4086         struct btrfs_trans_handle *trans;
4087         struct inode *inode = d_inode(dentry);
4088         int ret;
4089
4090         trans = __unlink_start_trans(dir);
4091         if (IS_ERR(trans))
4092                 return PTR_ERR(trans);
4093
4094         btrfs_record_unlink_dir(trans, dir, d_inode(dentry), 0);
4095
4096         ret = btrfs_unlink_inode(trans, root, dir, d_inode(dentry),
4097                                  dentry->d_name.name, dentry->d_name.len);
4098         if (ret)
4099                 goto out;
4100
4101         if (inode->i_nlink == 0) {
4102                 ret = btrfs_orphan_add(trans, inode);
4103                 if (ret)
4104                         goto out;
4105         }
4106
4107 out:
4108         btrfs_end_transaction(trans, root);
4109         btrfs_btree_balance_dirty(root);
4110         return ret;
4111 }
4112
4113 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
4114                         struct btrfs_root *root,
4115                         struct inode *dir, u64 objectid,
4116                         const char *name, int name_len)
4117 {
4118         struct btrfs_path *path;
4119         struct extent_buffer *leaf;
4120         struct btrfs_dir_item *di;
4121         struct btrfs_key key;
4122         u64 index;
4123         int ret;
4124         u64 dir_ino = btrfs_ino(dir);
4125
4126         path = btrfs_alloc_path();
4127         if (!path)
4128                 return -ENOMEM;
4129
4130         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
4131                                    name, name_len, -1);
4132         if (IS_ERR_OR_NULL(di)) {
4133                 if (!di)
4134                         ret = -ENOENT;
4135                 else
4136                         ret = PTR_ERR(di);
4137                 goto out;
4138         }
4139
4140         leaf = path->nodes[0];
4141         btrfs_dir_item_key_to_cpu(leaf, di, &key);
4142         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
4143         ret = btrfs_delete_one_dir_name(trans, root, path, di);
4144         if (ret) {
4145                 btrfs_abort_transaction(trans, root, ret);
4146                 goto out;
4147         }
4148         btrfs_release_path(path);
4149
4150         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
4151                                  objectid, root->root_key.objectid,
4152                                  dir_ino, &index, name, name_len);
4153         if (ret < 0) {
4154                 if (ret != -ENOENT) {
4155                         btrfs_abort_transaction(trans, root, ret);
4156                         goto out;
4157                 }
4158                 di = btrfs_search_dir_index_item(root, path, dir_ino,
4159                                                  name, name_len);
4160                 if (IS_ERR_OR_NULL(di)) {
4161                         if (!di)
4162                                 ret = -ENOENT;
4163                         else
4164                                 ret = PTR_ERR(di);
4165                         btrfs_abort_transaction(trans, root, ret);
4166                         goto out;
4167                 }
4168
4169                 leaf = path->nodes[0];
4170                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4171                 btrfs_release_path(path);
4172                 index = key.offset;
4173         }
4174         btrfs_release_path(path);
4175
4176         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
4177         if (ret) {
4178                 btrfs_abort_transaction(trans, root, ret);
4179                 goto out;
4180         }
4181
4182         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
4183         inode_inc_iversion(dir);
4184         dir->i_mtime = dir->i_ctime = current_fs_time(dir->i_sb);
4185         ret = btrfs_update_inode_fallback(trans, root, dir);
4186         if (ret)
4187                 btrfs_abort_transaction(trans, root, ret);
4188 out:
4189         btrfs_free_path(path);
4190         return ret;
4191 }
4192
4193 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
4194 {
4195         struct inode *inode = d_inode(dentry);
4196         int err = 0;
4197         struct btrfs_root *root = BTRFS_I(dir)->root;
4198         struct btrfs_trans_handle *trans;
4199
4200         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
4201                 return -ENOTEMPTY;
4202         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
4203                 return -EPERM;
4204
4205         trans = __unlink_start_trans(dir);
4206         if (IS_ERR(trans))
4207                 return PTR_ERR(trans);
4208
4209         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
4210                 err = btrfs_unlink_subvol(trans, root, dir,
4211                                           BTRFS_I(inode)->location.objectid,
4212                                           dentry->d_name.name,
4213                                           dentry->d_name.len);
4214                 goto out;
4215         }
4216
4217         err = btrfs_orphan_add(trans, inode);
4218         if (err)
4219                 goto out;
4220
4221         /* now the directory is empty */
4222         err = btrfs_unlink_inode(trans, root, dir, d_inode(dentry),
4223                                  dentry->d_name.name, dentry->d_name.len);
4224         if (!err)
4225                 btrfs_i_size_write(inode, 0);
4226 out:
4227         btrfs_end_transaction(trans, root);
4228         btrfs_btree_balance_dirty(root);
4229
4230         return err;
4231 }
4232
4233 static int truncate_space_check(struct btrfs_trans_handle *trans,
4234                                 struct btrfs_root *root,
4235                                 u64 bytes_deleted)
4236 {
4237         int ret;
4238
4239         /*
4240          * This is only used to apply pressure to the enospc system, we don't
4241          * intend to use this reservation at all.
4242          */
4243         bytes_deleted = btrfs_csum_bytes_to_leaves(root, bytes_deleted);
4244         bytes_deleted *= root->nodesize;
4245         ret = btrfs_block_rsv_add(root, &root->fs_info->trans_block_rsv,
4246                                   bytes_deleted, BTRFS_RESERVE_NO_FLUSH);
4247         if (!ret) {
4248                 trace_btrfs_space_reservation(root->fs_info, "transaction",
4249                                               trans->transid,
4250                                               bytes_deleted, 1);
4251                 trans->bytes_reserved += bytes_deleted;
4252         }
4253         return ret;
4254
4255 }
4256
4257 static int truncate_inline_extent(struct inode *inode,
4258                                   struct btrfs_path *path,
4259                                   struct btrfs_key *found_key,
4260                                   const u64 item_end,
4261                                   const u64 new_size)
4262 {
4263         struct extent_buffer *leaf = path->nodes[0];
4264         int slot = path->slots[0];
4265         struct btrfs_file_extent_item *fi;
4266         u32 size = (u32)(new_size - found_key->offset);
4267         struct btrfs_root *root = BTRFS_I(inode)->root;
4268
4269         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
4270
4271         if (btrfs_file_extent_compression(leaf, fi) != BTRFS_COMPRESS_NONE) {
4272                 loff_t offset = new_size;
4273                 loff_t page_end = ALIGN(offset, PAGE_SIZE);
4274
4275                 /*
4276                  * Zero out the remaining of the last page of our inline extent,
4277                  * instead of directly truncating our inline extent here - that
4278                  * would be much more complex (decompressing all the data, then
4279                  * compressing the truncated data, which might be bigger than
4280                  * the size of the inline extent, resize the extent, etc).
4281                  * We release the path because to get the page we might need to
4282                  * read the extent item from disk (data not in the page cache).
4283                  */
4284                 btrfs_release_path(path);
4285                 return btrfs_truncate_block(inode, offset, page_end - offset,
4286                                         0);
4287         }
4288
4289         btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4290         size = btrfs_file_extent_calc_inline_size(size);
4291         btrfs_truncate_item(root, path, size, 1);
4292
4293         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4294                 inode_sub_bytes(inode, item_end + 1 - new_size);
4295
4296         return 0;
4297 }
4298
4299 /*
4300  * this can truncate away extent items, csum items and directory items.
4301  * It starts at a high offset and removes keys until it can't find
4302  * any higher than new_size
4303  *
4304  * csum items that cross the new i_size are truncated to the new size
4305  * as well.
4306  *
4307  * min_type is the minimum key type to truncate down to.  If set to 0, this
4308  * will kill all the items on this inode, including the INODE_ITEM_KEY.
4309  */
4310 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
4311                                struct btrfs_root *root,
4312                                struct inode *inode,
4313                                u64 new_size, u32 min_type)
4314 {
4315         struct btrfs_path *path;
4316         struct extent_buffer *leaf;
4317         struct btrfs_file_extent_item *fi;
4318         struct btrfs_key key;
4319         struct btrfs_key found_key;
4320         u64 extent_start = 0;
4321         u64 extent_num_bytes = 0;
4322         u64 extent_offset = 0;
4323         u64 item_end = 0;
4324         u64 last_size = new_size;
4325         u32 found_type = (u8)-1;
4326         int found_extent;
4327         int del_item;
4328         int pending_del_nr = 0;
4329         int pending_del_slot = 0;
4330         int extent_type = -1;
4331         int ret;
4332         int err = 0;
4333         u64 ino = btrfs_ino(inode);
4334         u64 bytes_deleted = 0;
4335         bool be_nice = 0;
4336         bool should_throttle = 0;
4337         bool should_end = 0;
4338
4339         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
4340
4341         /*
4342          * for non-free space inodes and ref cows, we want to back off from
4343          * time to time
4344          */
4345         if (!btrfs_is_free_space_inode(inode) &&
4346             test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4347                 be_nice = 1;
4348
4349         path = btrfs_alloc_path();
4350         if (!path)
4351                 return -ENOMEM;
4352         path->reada = READA_BACK;
4353
4354         /*
4355          * We want to drop from the next block forward in case this new size is
4356          * not block aligned since we will be keeping the last block of the
4357          * extent just the way it is.
4358          */
4359         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4360             root == root->fs_info->tree_root)
4361                 btrfs_drop_extent_cache(inode, ALIGN(new_size,
4362                                         root->sectorsize), (u64)-1, 0);
4363
4364         /*
4365          * This function is also used to drop the items in the log tree before
4366          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4367          * it is used to drop the loged items. So we shouldn't kill the delayed
4368          * items.
4369          */
4370         if (min_type == 0 && root == BTRFS_I(inode)->root)
4371                 btrfs_kill_delayed_inode_items(inode);
4372
4373         key.objectid = ino;
4374         key.offset = (u64)-1;
4375         key.type = (u8)-1;
4376
4377 search_again:
4378         /*
4379          * with a 16K leaf size and 128MB extents, you can actually queue
4380          * up a huge file in a single leaf.  Most of the time that
4381          * bytes_deleted is > 0, it will be huge by the time we get here
4382          */
4383         if (be_nice && bytes_deleted > SZ_32M) {
4384                 if (btrfs_should_end_transaction(trans, root)) {
4385                         err = -EAGAIN;
4386                         goto error;
4387                 }
4388         }
4389
4390
4391         path->leave_spinning = 1;
4392         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4393         if (ret < 0) {
4394                 err = ret;
4395                 goto out;
4396         }
4397
4398         if (ret > 0) {
4399                 /* there are no items in the tree for us to truncate, we're
4400                  * done
4401                  */
4402                 if (path->slots[0] == 0)
4403                         goto out;
4404                 path->slots[0]--;
4405         }
4406
4407         while (1) {
4408                 fi = NULL;
4409                 leaf = path->nodes[0];
4410                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4411                 found_type = found_key.type;
4412
4413                 if (found_key.objectid != ino)
4414                         break;
4415
4416                 if (found_type < min_type)
4417                         break;
4418
4419                 item_end = found_key.offset;
4420                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4421                         fi = btrfs_item_ptr(leaf, path->slots[0],
4422                                             struct btrfs_file_extent_item);
4423                         extent_type = btrfs_file_extent_type(leaf, fi);
4424                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4425                                 item_end +=
4426                                     btrfs_file_extent_num_bytes(leaf, fi);
4427                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4428                                 item_end += btrfs_file_extent_inline_len(leaf,
4429                                                          path->slots[0], fi);
4430                         }
4431                         item_end--;
4432                 }
4433                 if (found_type > min_type) {
4434                         del_item = 1;
4435                 } else {
4436                         if (item_end < new_size)
4437                                 break;
4438                         if (found_key.offset >= new_size)
4439                                 del_item = 1;
4440                         else
4441                                 del_item = 0;
4442                 }
4443                 found_extent = 0;
4444                 /* FIXME, shrink the extent if the ref count is only 1 */
4445                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4446                         goto delete;
4447
4448                 if (del_item)
4449                         last_size = found_key.offset;
4450                 else
4451                         last_size = new_size;
4452
4453                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4454                         u64 num_dec;
4455                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4456                         if (!del_item) {
4457                                 u64 orig_num_bytes =
4458                                         btrfs_file_extent_num_bytes(leaf, fi);
4459                                 extent_num_bytes = ALIGN(new_size -
4460                                                 found_key.offset,
4461                                                 root->sectorsize);
4462                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4463                                                          extent_num_bytes);
4464                                 num_dec = (orig_num_bytes -
4465                                            extent_num_bytes);
4466                                 if (test_bit(BTRFS_ROOT_REF_COWS,
4467                                              &root->state) &&
4468                                     extent_start != 0)
4469                                         inode_sub_bytes(inode, num_dec);
4470                                 btrfs_mark_buffer_dirty(leaf);
4471                         } else {
4472                                 extent_num_bytes =
4473                                         btrfs_file_extent_disk_num_bytes(leaf,
4474                                                                          fi);
4475                                 extent_offset = found_key.offset -
4476                                         btrfs_file_extent_offset(leaf, fi);
4477
4478                                 /* FIXME blocksize != 4096 */
4479                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4480                                 if (extent_start != 0) {
4481                                         found_extent = 1;
4482                                         if (test_bit(BTRFS_ROOT_REF_COWS,
4483                                                      &root->state))
4484                                                 inode_sub_bytes(inode, num_dec);
4485                                 }
4486                         }
4487                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4488                         /*
4489                          * we can't truncate inline items that have had
4490                          * special encodings
4491                          */
4492                         if (!del_item &&
4493                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4494                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
4495
4496                                 /*
4497                                  * Need to release path in order to truncate a
4498                                  * compressed extent. So delete any accumulated
4499                                  * extent items so far.
4500                                  */
4501                                 if (btrfs_file_extent_compression(leaf, fi) !=
4502                                     BTRFS_COMPRESS_NONE && pending_del_nr) {
4503                                         err = btrfs_del_items(trans, root, path,
4504                                                               pending_del_slot,
4505                                                               pending_del_nr);
4506                                         if (err) {
4507                                                 btrfs_abort_transaction(trans,
4508                                                                         root,
4509                                                                         err);
4510                                                 goto error;
4511                                         }
4512                                         pending_del_nr = 0;
4513                                 }
4514
4515                                 err = truncate_inline_extent(inode, path,
4516                                                              &found_key,
4517                                                              item_end,
4518                                                              new_size);
4519                                 if (err) {
4520                                         btrfs_abort_transaction(trans,
4521                                                                 root, err);
4522                                         goto error;
4523                                 }
4524                         } else if (test_bit(BTRFS_ROOT_REF_COWS,
4525                                             &root->state)) {
4526                                 inode_sub_bytes(inode, item_end + 1 - new_size);
4527                         }
4528                 }
4529 delete:
4530                 if (del_item) {
4531                         if (!pending_del_nr) {
4532                                 /* no pending yet, add ourselves */
4533                                 pending_del_slot = path->slots[0];
4534                                 pending_del_nr = 1;
4535                         } else if (pending_del_nr &&
4536                                    path->slots[0] + 1 == pending_del_slot) {
4537                                 /* hop on the pending chunk */
4538                                 pending_del_nr++;
4539                                 pending_del_slot = path->slots[0];
4540                         } else {
4541                                 BUG();
4542                         }
4543                 } else {
4544                         break;
4545                 }
4546                 should_throttle = 0;
4547
4548                 if (found_extent &&
4549                     (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4550                      root == root->fs_info->tree_root)) {
4551                         btrfs_set_path_blocking(path);
4552                         bytes_deleted += extent_num_bytes;
4553                         ret = btrfs_free_extent(trans, root, extent_start,
4554                                                 extent_num_bytes, 0,
4555                                                 btrfs_header_owner(leaf),
4556                                                 ino, extent_offset);
4557                         BUG_ON(ret);
4558                         if (btrfs_should_throttle_delayed_refs(trans, root))
4559                                 btrfs_async_run_delayed_refs(root,
4560                                                              trans->transid,
4561                                         trans->delayed_ref_updates * 2, 0);
4562                         if (be_nice) {
4563                                 if (truncate_space_check(trans, root,
4564                                                          extent_num_bytes)) {
4565                                         should_end = 1;
4566                                 }
4567                                 if (btrfs_should_throttle_delayed_refs(trans,
4568                                                                        root)) {
4569                                         should_throttle = 1;
4570                                 }
4571                         }
4572                 }
4573
4574                 if (found_type == BTRFS_INODE_ITEM_KEY)
4575                         break;
4576
4577                 if (path->slots[0] == 0 ||
4578                     path->slots[0] != pending_del_slot ||
4579                     should_throttle || should_end) {
4580                         if (pending_del_nr) {
4581                                 ret = btrfs_del_items(trans, root, path,
4582                                                 pending_del_slot,
4583                                                 pending_del_nr);
4584                                 if (ret) {
4585                                         btrfs_abort_transaction(trans,
4586                                                                 root, ret);
4587                                         goto error;
4588                                 }
4589                                 pending_del_nr = 0;
4590                         }
4591                         btrfs_release_path(path);
4592                         if (should_throttle) {
4593                                 unsigned long updates = trans->delayed_ref_updates;
4594                                 if (updates) {
4595                                         trans->delayed_ref_updates = 0;
4596                                         ret = btrfs_run_delayed_refs(trans, root, updates * 2);
4597                                         if (ret && !err)
4598                                                 err = ret;
4599                                 }
4600                         }
4601                         /*
4602                          * if we failed to refill our space rsv, bail out
4603                          * and let the transaction restart
4604                          */
4605                         if (should_end) {
4606                                 err = -EAGAIN;
4607                                 goto error;
4608                         }
4609                         goto search_again;
4610                 } else {
4611                         path->slots[0]--;
4612                 }
4613         }
4614 out:
4615         if (pending_del_nr) {
4616                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
4617                                       pending_del_nr);
4618                 if (ret)
4619                         btrfs_abort_transaction(trans, root, ret);
4620         }
4621 error:
4622         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
4623                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4624
4625         btrfs_free_path(path);
4626
4627         if (be_nice && bytes_deleted > SZ_32M) {
4628                 unsigned long updates = trans->delayed_ref_updates;
4629                 if (updates) {
4630                         trans->delayed_ref_updates = 0;
4631                         ret = btrfs_run_delayed_refs(trans, root, updates * 2);
4632                         if (ret && !err)
4633                                 err = ret;
4634                 }
4635         }
4636         return err;
4637 }
4638
4639 /*
4640  * btrfs_truncate_block - read, zero a chunk and write a block
4641  * @inode - inode that we're zeroing
4642  * @from - the offset to start zeroing
4643  * @len - the length to zero, 0 to zero the entire range respective to the
4644  *      offset
4645  * @front - zero up to the offset instead of from the offset on
4646  *
4647  * This will find the block for the "from" offset and cow the block and zero the
4648  * part we want to zero.  This is used with truncate and hole punching.
4649  */
4650 int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len,
4651                         int front)
4652 {
4653         struct address_space *mapping = inode->i_mapping;
4654         struct btrfs_root *root = BTRFS_I(inode)->root;
4655         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4656         struct btrfs_ordered_extent *ordered;
4657         struct extent_state *cached_state = NULL;
4658         char *kaddr;
4659         u32 blocksize = root->sectorsize;
4660         pgoff_t index = from >> PAGE_SHIFT;
4661         unsigned offset = from & (blocksize - 1);
4662         struct page *page;
4663         gfp_t mask = btrfs_alloc_write_mask(mapping);
4664         int ret = 0;
4665         u64 block_start;
4666         u64 block_end;
4667
4668         if ((offset & (blocksize - 1)) == 0 &&
4669             (!len || ((len & (blocksize - 1)) == 0)))
4670                 goto out;
4671
4672         ret = btrfs_delalloc_reserve_space(inode,
4673                         round_down(from, blocksize), blocksize);
4674         if (ret)
4675                 goto out;
4676
4677 again:
4678         page = find_or_create_page(mapping, index, mask);
4679         if (!page) {
4680                 btrfs_delalloc_release_space(inode,
4681                                 round_down(from, blocksize),
4682                                 blocksize);
4683                 ret = -ENOMEM;
4684                 goto out;
4685         }
4686
4687         block_start = round_down(from, blocksize);
4688         block_end = block_start + blocksize - 1;
4689
4690         if (!PageUptodate(page)) {
4691                 ret = btrfs_readpage(NULL, page);
4692                 lock_page(page);
4693                 if (page->mapping != mapping) {
4694                         unlock_page(page);
4695                         put_page(page);
4696                         goto again;
4697                 }
4698                 if (!PageUptodate(page)) {
4699                         ret = -EIO;
4700                         goto out_unlock;
4701                 }
4702         }
4703         wait_on_page_writeback(page);
4704
4705         lock_extent_bits(io_tree, block_start, block_end, &cached_state);
4706         set_page_extent_mapped(page);
4707
4708         ordered = btrfs_lookup_ordered_extent(inode, block_start);
4709         if (ordered) {
4710                 unlock_extent_cached(io_tree, block_start, block_end,
4711                                      &cached_state, GFP_NOFS);
4712                 unlock_page(page);
4713                 put_page(page);
4714                 btrfs_start_ordered_extent(inode, ordered, 1);
4715                 btrfs_put_ordered_extent(ordered);
4716                 goto again;
4717         }
4718
4719         clear_extent_bit(&BTRFS_I(inode)->io_tree, block_start, block_end,
4720                           EXTENT_DIRTY | EXTENT_DELALLOC |
4721                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4722                           0, 0, &cached_state, GFP_NOFS);
4723
4724         ret = btrfs_set_extent_delalloc(inode, block_start, block_end,
4725                                         &cached_state);
4726         if (ret) {
4727                 unlock_extent_cached(io_tree, block_start, block_end,
4728                                      &cached_state, GFP_NOFS);
4729                 goto out_unlock;
4730         }
4731
4732         if (offset != blocksize) {
4733                 if (!len)
4734                         len = blocksize - offset;
4735                 kaddr = kmap(page);
4736                 if (front)
4737                         memset(kaddr + (block_start - page_offset(page)),
4738                                 0, offset);
4739                 else
4740                         memset(kaddr + (block_start - page_offset(page)) +  offset,
4741                                 0, len);
4742                 flush_dcache_page(page);
4743                 kunmap(page);
4744         }
4745         ClearPageChecked(page);
4746         set_page_dirty(page);
4747         unlock_extent_cached(io_tree, block_start, block_end, &cached_state,
4748                              GFP_NOFS);
4749
4750 out_unlock:
4751         if (ret)
4752                 btrfs_delalloc_release_space(inode, block_start,
4753                                              blocksize);
4754         unlock_page(page);
4755         put_page(page);
4756 out:
4757         return ret;
4758 }
4759
4760 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4761                              u64 offset, u64 len)
4762 {
4763         struct btrfs_trans_handle *trans;
4764         int ret;
4765
4766         /*
4767          * Still need to make sure the inode looks like it's been updated so
4768          * that any holes get logged if we fsync.
4769          */
4770         if (btrfs_fs_incompat(root->fs_info, NO_HOLES)) {
4771                 BTRFS_I(inode)->last_trans = root->fs_info->generation;
4772                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4773                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4774                 return 0;
4775         }
4776
4777         /*
4778          * 1 - for the one we're dropping
4779          * 1 - for the one we're adding
4780          * 1 - for updating the inode.
4781          */
4782         trans = btrfs_start_transaction(root, 3);
4783         if (IS_ERR(trans))
4784                 return PTR_ERR(trans);
4785
4786         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4787         if (ret) {
4788                 btrfs_abort_transaction(trans, root, ret);
4789                 btrfs_end_transaction(trans, root);
4790                 return ret;
4791         }
4792
4793         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
4794                                        0, 0, len, 0, len, 0, 0, 0);
4795         if (ret)
4796                 btrfs_abort_transaction(trans, root, ret);
4797         else
4798                 btrfs_update_inode(trans, root, inode);
4799         btrfs_end_transaction(trans, root);
4800         return ret;
4801 }
4802
4803 /*
4804  * This function puts in dummy file extents for the area we're creating a hole
4805  * for.  So if we are truncating this file to a larger size we need to insert
4806  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4807  * the range between oldsize and size
4808  */
4809 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4810 {
4811         struct btrfs_root *root = BTRFS_I(inode)->root;
4812         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4813         struct extent_map *em = NULL;
4814         struct extent_state *cached_state = NULL;
4815         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4816         u64 hole_start = ALIGN(oldsize, root->sectorsize);
4817         u64 block_end = ALIGN(size, root->sectorsize);
4818         u64 last_byte;
4819         u64 cur_offset;
4820         u64 hole_size;
4821         int err = 0;
4822
4823         /*
4824          * If our size started in the middle of a block we need to zero out the
4825          * rest of the block before we expand the i_size, otherwise we could
4826          * expose stale data.
4827          */
4828         err = btrfs_truncate_block(inode, oldsize, 0, 0);
4829         if (err)
4830                 return err;
4831
4832         if (size <= hole_start)
4833                 return 0;
4834
4835         while (1) {
4836                 struct btrfs_ordered_extent *ordered;
4837
4838                 lock_extent_bits(io_tree, hole_start, block_end - 1,
4839                                  &cached_state);
4840                 ordered = btrfs_lookup_ordered_range(inode, hole_start,
4841                                                      block_end - hole_start);
4842                 if (!ordered)
4843                         break;
4844                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
4845                                      &cached_state, GFP_NOFS);
4846                 btrfs_start_ordered_extent(inode, ordered, 1);
4847                 btrfs_put_ordered_extent(ordered);
4848         }
4849
4850         cur_offset = hole_start;
4851         while (1) {
4852                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
4853                                 block_end - cur_offset, 0);
4854                 if (IS_ERR(em)) {
4855                         err = PTR_ERR(em);
4856                         em = NULL;
4857                         break;
4858                 }
4859                 last_byte = min(extent_map_end(em), block_end);
4860                 last_byte = ALIGN(last_byte , root->sectorsize);
4861                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4862                         struct extent_map *hole_em;
4863                         hole_size = last_byte - cur_offset;
4864
4865                         err = maybe_insert_hole(root, inode, cur_offset,
4866                                                 hole_size);
4867                         if (err)
4868                                 break;
4869                         btrfs_drop_extent_cache(inode, cur_offset,
4870                                                 cur_offset + hole_size - 1, 0);
4871                         hole_em = alloc_extent_map();
4872                         if (!hole_em) {
4873                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4874                                         &BTRFS_I(inode)->runtime_flags);
4875                                 goto next;
4876                         }
4877                         hole_em->start = cur_offset;
4878                         hole_em->len = hole_size;
4879                         hole_em->orig_start = cur_offset;
4880
4881                         hole_em->block_start = EXTENT_MAP_HOLE;
4882                         hole_em->block_len = 0;
4883                         hole_em->orig_block_len = 0;
4884                         hole_em->ram_bytes = hole_size;
4885                         hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
4886                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4887                         hole_em->generation = root->fs_info->generation;
4888
4889                         while (1) {
4890                                 write_lock(&em_tree->lock);
4891                                 err = add_extent_mapping(em_tree, hole_em, 1);
4892                                 write_unlock(&em_tree->lock);
4893                                 if (err != -EEXIST)
4894                                         break;
4895                                 btrfs_drop_extent_cache(inode, cur_offset,
4896                                                         cur_offset +
4897                                                         hole_size - 1, 0);
4898                         }
4899                         free_extent_map(hole_em);
4900                 }
4901 next:
4902                 free_extent_map(em);
4903                 em = NULL;
4904                 cur_offset = last_byte;
4905                 if (cur_offset >= block_end)
4906                         break;
4907         }
4908         free_extent_map(em);
4909         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
4910                              GFP_NOFS);
4911         return err;
4912 }
4913
4914 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4915 {
4916         struct btrfs_root *root = BTRFS_I(inode)->root;
4917         struct btrfs_trans_handle *trans;
4918         loff_t oldsize = i_size_read(inode);
4919         loff_t newsize = attr->ia_size;
4920         int mask = attr->ia_valid;
4921         int ret;
4922
4923         /*
4924          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4925          * special case where we need to update the times despite not having
4926          * these flags set.  For all other operations the VFS set these flags
4927          * explicitly if it wants a timestamp update.
4928          */
4929         if (newsize != oldsize) {
4930                 inode_inc_iversion(inode);
4931                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
4932                         inode->i_ctime = inode->i_mtime =
4933                                 current_fs_time(inode->i_sb);
4934         }
4935
4936         if (newsize > oldsize) {
4937                 /*
4938                  * Don't do an expanding truncate while snapshoting is ongoing.
4939                  * This is to ensure the snapshot captures a fully consistent
4940                  * state of this file - if the snapshot captures this expanding
4941                  * truncation, it must capture all writes that happened before
4942                  * this truncation.
4943                  */
4944                 btrfs_wait_for_snapshot_creation(root);
4945                 ret = btrfs_cont_expand(inode, oldsize, newsize);
4946                 if (ret) {
4947                         btrfs_end_write_no_snapshoting(root);
4948                         return ret;
4949                 }
4950
4951                 trans = btrfs_start_transaction(root, 1);
4952                 if (IS_ERR(trans)) {
4953                         btrfs_end_write_no_snapshoting(root);
4954                         return PTR_ERR(trans);
4955                 }
4956
4957                 i_size_write(inode, newsize);
4958                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
4959                 pagecache_isize_extended(inode, oldsize, newsize);
4960                 ret = btrfs_update_inode(trans, root, inode);
4961                 btrfs_end_write_no_snapshoting(root);
4962                 btrfs_end_transaction(trans, root);
4963         } else {
4964
4965                 /*
4966                  * We're truncating a file that used to have good data down to
4967                  * zero. Make sure it gets into the ordered flush list so that
4968                  * any new writes get down to disk quickly.
4969                  */
4970                 if (newsize == 0)
4971                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
4972                                 &BTRFS_I(inode)->runtime_flags);
4973
4974                 /*
4975                  * 1 for the orphan item we're going to add
4976                  * 1 for the orphan item deletion.
4977                  */
4978                 trans = btrfs_start_transaction(root, 2);
4979                 if (IS_ERR(trans))
4980                         return PTR_ERR(trans);
4981
4982                 /*
4983                  * We need to do this in case we fail at _any_ point during the
4984                  * actual truncate.  Once we do the truncate_setsize we could
4985                  * invalidate pages which forces any outstanding ordered io to
4986                  * be instantly completed which will give us extents that need
4987                  * to be truncated.  If we fail to get an orphan inode down we
4988                  * could have left over extents that were never meant to live,
4989                  * so we need to guarantee from this point on that everything
4990                  * will be consistent.
4991                  */
4992                 ret = btrfs_orphan_add(trans, inode);
4993                 btrfs_end_transaction(trans, root);
4994                 if (ret)
4995                         return ret;
4996
4997                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
4998                 truncate_setsize(inode, newsize);
4999
5000                 /* Disable nonlocked read DIO to avoid the end less truncate */
5001                 btrfs_inode_block_unlocked_dio(inode);
5002                 inode_dio_wait(inode);
5003                 btrfs_inode_resume_unlocked_dio(inode);
5004
5005                 ret = btrfs_truncate(inode);
5006                 if (ret && inode->i_nlink) {
5007                         int err;
5008
5009                         /*
5010                          * failed to truncate, disk_i_size is only adjusted down
5011                          * as we remove extents, so it should represent the true
5012                          * size of the inode, so reset the in memory size and
5013                          * delete our orphan entry.
5014                          */
5015                         trans = btrfs_join_transaction(root);
5016                         if (IS_ERR(trans)) {
5017                                 btrfs_orphan_del(NULL, inode);
5018                                 return ret;
5019                         }
5020                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
5021                         err = btrfs_orphan_del(trans, inode);
5022                         if (err)
5023                                 btrfs_abort_transaction(trans, root, err);
5024                         btrfs_end_transaction(trans, root);
5025                 }
5026         }
5027
5028         return ret;
5029 }
5030
5031 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
5032 {
5033         struct inode *inode = d_inode(dentry);
5034         struct btrfs_root *root = BTRFS_I(inode)->root;
5035         int err;
5036
5037         if (btrfs_root_readonly(root))
5038                 return -EROFS;
5039
5040         err = inode_change_ok(inode, attr);
5041         if (err)
5042                 return err;
5043
5044         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
5045                 err = btrfs_setsize(inode, attr);
5046                 if (err)
5047                         return err;
5048         }
5049
5050         if (attr->ia_valid) {
5051                 setattr_copy(inode, attr);
5052                 inode_inc_iversion(inode);
5053                 err = btrfs_dirty_inode(inode);
5054
5055                 if (!err && attr->ia_valid & ATTR_MODE)
5056                         err = posix_acl_chmod(inode, inode->i_mode);
5057         }
5058
5059         return err;
5060 }
5061
5062 /*
5063  * While truncating the inode pages during eviction, we get the VFS calling
5064  * btrfs_invalidatepage() against each page of the inode. This is slow because
5065  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
5066  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
5067  * extent_state structures over and over, wasting lots of time.
5068  *
5069  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
5070  * those expensive operations on a per page basis and do only the ordered io
5071  * finishing, while we release here the extent_map and extent_state structures,
5072  * without the excessive merging and splitting.
5073  */
5074 static void evict_inode_truncate_pages(struct inode *inode)
5075 {
5076         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5077         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
5078         struct rb_node *node;
5079
5080         ASSERT(inode->i_state & I_FREEING);
5081         truncate_inode_pages_final(&inode->i_data);
5082
5083         write_lock(&map_tree->lock);
5084         while (!RB_EMPTY_ROOT(&map_tree->map)) {
5085                 struct extent_map *em;
5086
5087                 node = rb_first(&map_tree->map);
5088                 em = rb_entry(node, struct extent_map, rb_node);
5089                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
5090                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
5091                 remove_extent_mapping(map_tree, em);
5092                 free_extent_map(em);
5093                 if (need_resched()) {
5094                         write_unlock(&map_tree->lock);
5095                         cond_resched();
5096                         write_lock(&map_tree->lock);
5097                 }
5098         }
5099         write_unlock(&map_tree->lock);
5100
5101         /*
5102          * Keep looping until we have no more ranges in the io tree.
5103          * We can have ongoing bios started by readpages (called from readahead)
5104          * that have their endio callback (extent_io.c:end_bio_extent_readpage)
5105          * still in progress (unlocked the pages in the bio but did not yet
5106          * unlocked the ranges in the io tree). Therefore this means some
5107          * ranges can still be locked and eviction started because before
5108          * submitting those bios, which are executed by a separate task (work
5109          * queue kthread), inode references (inode->i_count) were not taken
5110          * (which would be dropped in the end io callback of each bio).
5111          * Therefore here we effectively end up waiting for those bios and
5112          * anyone else holding locked ranges without having bumped the inode's
5113          * reference count - if we don't do it, when they access the inode's
5114          * io_tree to unlock a range it may be too late, leading to an
5115          * use-after-free issue.
5116          */
5117         spin_lock(&io_tree->lock);
5118         while (!RB_EMPTY_ROOT(&io_tree->state)) {
5119                 struct extent_state *state;
5120                 struct extent_state *cached_state = NULL;
5121                 u64 start;
5122                 u64 end;
5123
5124                 node = rb_first(&io_tree->state);
5125                 state = rb_entry(node, struct extent_state, rb_node);
5126                 start = state->start;
5127                 end = state->end;
5128                 spin_unlock(&io_tree->lock);
5129
5130                 lock_extent_bits(io_tree, start, end, &cached_state);
5131
5132                 /*
5133                  * If still has DELALLOC flag, the extent didn't reach disk,
5134                  * and its reserved space won't be freed by delayed_ref.
5135                  * So we need to free its reserved space here.
5136                  * (Refer to comment in btrfs_invalidatepage, case 2)
5137                  *
5138                  * Note, end is the bytenr of last byte, so we need + 1 here.
5139                  */
5140                 if (state->state & EXTENT_DELALLOC)
5141                         btrfs_qgroup_free_data(inode, start, end - start + 1);
5142
5143                 clear_extent_bit(io_tree, start, end,
5144                                  EXTENT_LOCKED | EXTENT_DIRTY |
5145                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
5146                                  EXTENT_DEFRAG, 1, 1,
5147                                  &cached_state, GFP_NOFS);
5148
5149                 cond_resched();
5150                 spin_lock(&io_tree->lock);
5151         }
5152         spin_unlock(&io_tree->lock);
5153 }
5154
5155 void btrfs_evict_inode(struct inode *inode)
5156 {
5157         struct btrfs_trans_handle *trans;
5158         struct btrfs_root *root = BTRFS_I(inode)->root;
5159         struct btrfs_block_rsv *rsv, *global_rsv;
5160         int steal_from_global = 0;
5161         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
5162         int ret;
5163
5164         trace_btrfs_inode_evict(inode);
5165
5166         evict_inode_truncate_pages(inode);
5167
5168         if (inode->i_nlink &&
5169             ((btrfs_root_refs(&root->root_item) != 0 &&
5170               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
5171              btrfs_is_free_space_inode(inode)))
5172                 goto no_delete;
5173
5174         if (is_bad_inode(inode)) {
5175                 btrfs_orphan_del(NULL, inode);
5176                 goto no_delete;
5177         }
5178         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
5179         if (!special_file(inode->i_mode))
5180                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
5181
5182         btrfs_free_io_failure_record(inode, 0, (u64)-1);
5183
5184         if (root->fs_info->log_root_recovering) {
5185                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
5186                                  &BTRFS_I(inode)->runtime_flags));
5187                 goto no_delete;
5188         }
5189
5190         if (inode->i_nlink > 0) {
5191                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
5192                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
5193                 goto no_delete;
5194         }
5195
5196         ret = btrfs_commit_inode_delayed_inode(inode);
5197         if (ret) {
5198                 btrfs_orphan_del(NULL, inode);
5199                 goto no_delete;
5200         }
5201
5202         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
5203         if (!rsv) {
5204                 btrfs_orphan_del(NULL, inode);
5205                 goto no_delete;
5206         }
5207         rsv->size = min_size;
5208         rsv->failfast = 1;
5209         global_rsv = &root->fs_info->global_block_rsv;
5210
5211         btrfs_i_size_write(inode, 0);
5212
5213         /*
5214          * This is a bit simpler than btrfs_truncate since we've already
5215          * reserved our space for our orphan item in the unlink, so we just
5216          * need to reserve some slack space in case we add bytes and update
5217          * inode item when doing the truncate.
5218          */
5219         while (1) {
5220                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
5221                                              BTRFS_RESERVE_FLUSH_LIMIT);
5222
5223                 /*
5224                  * Try and steal from the global reserve since we will
5225                  * likely not use this space anyway, we want to try as
5226                  * hard as possible to get this to work.
5227                  */
5228                 if (ret)
5229                         steal_from_global++;
5230                 else
5231                         steal_from_global = 0;
5232                 ret = 0;
5233
5234                 /*
5235                  * steal_from_global == 0: we reserved stuff, hooray!
5236                  * steal_from_global == 1: we didn't reserve stuff, boo!
5237                  * steal_from_global == 2: we've committed, still not a lot of
5238                  * room but maybe we'll have room in the global reserve this
5239                  * time.
5240                  * steal_from_global == 3: abandon all hope!
5241                  */
5242                 if (steal_from_global > 2) {
5243                         btrfs_warn(root->fs_info,
5244                                 "Could not get space for a delete, will truncate on mount %d",
5245                                 ret);
5246                         btrfs_orphan_del(NULL, inode);
5247                         btrfs_free_block_rsv(root, rsv);
5248                         goto no_delete;
5249                 }
5250
5251                 trans = btrfs_join_transaction(root);
5252                 if (IS_ERR(trans)) {
5253                         btrfs_orphan_del(NULL, inode);
5254                         btrfs_free_block_rsv(root, rsv);
5255                         goto no_delete;
5256                 }
5257
5258                 /*
5259                  * We can't just steal from the global reserve, we need to make
5260                  * sure there is room to do it, if not we need to commit and try
5261                  * again.
5262                  */
5263                 if (steal_from_global) {
5264                         if (!btrfs_check_space_for_delayed_refs(trans, root))
5265                                 ret = btrfs_block_rsv_migrate(global_rsv, rsv,
5266                                                               min_size);
5267                         else
5268                                 ret = -ENOSPC;
5269                 }
5270
5271                 /*
5272                  * Couldn't steal from the global reserve, we have too much
5273                  * pending stuff built up, commit the transaction and try it
5274                  * again.
5275                  */
5276                 if (ret) {
5277                         ret = btrfs_commit_transaction(trans, root);
5278                         if (ret) {
5279                                 btrfs_orphan_del(NULL, inode);
5280                                 btrfs_free_block_rsv(root, rsv);
5281                                 goto no_delete;
5282                         }
5283                         continue;
5284                 } else {
5285                         steal_from_global = 0;
5286                 }
5287
5288                 trans->block_rsv = rsv;
5289
5290                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
5291                 if (ret != -ENOSPC && ret != -EAGAIN)
5292                         break;
5293
5294                 trans->block_rsv = &root->fs_info->trans_block_rsv;
5295                 btrfs_end_transaction(trans, root);
5296                 trans = NULL;
5297                 btrfs_btree_balance_dirty(root);
5298         }
5299
5300         btrfs_free_block_rsv(root, rsv);
5301
5302         /*
5303          * Errors here aren't a big deal, it just means we leave orphan items
5304          * in the tree.  They will be cleaned up on the next mount.
5305          */
5306         if (ret == 0) {
5307                 trans->block_rsv = root->orphan_block_rsv;
5308                 btrfs_orphan_del(trans, inode);
5309         } else {
5310                 btrfs_orphan_del(NULL, inode);
5311         }
5312
5313         trans->block_rsv = &root->fs_info->trans_block_rsv;
5314         if (!(root == root->fs_info->tree_root ||
5315               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
5316                 btrfs_return_ino(root, btrfs_ino(inode));
5317
5318         btrfs_end_transaction(trans, root);
5319         btrfs_btree_balance_dirty(root);
5320 no_delete:
5321         btrfs_remove_delayed_node(inode);
5322         clear_inode(inode);
5323 }
5324
5325 /*
5326  * this returns the key found in the dir entry in the location pointer.
5327  * If no dir entries were found, location->objectid is 0.
5328  */
5329 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
5330                                struct btrfs_key *location)
5331 {
5332         const char *name = dentry->d_name.name;
5333         int namelen = dentry->d_name.len;
5334         struct btrfs_dir_item *di;
5335         struct btrfs_path *path;
5336         struct btrfs_root *root = BTRFS_I(dir)->root;
5337         int ret = 0;
5338
5339         path = btrfs_alloc_path();
5340         if (!path)
5341                 return -ENOMEM;
5342
5343         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
5344                                     namelen, 0);
5345         if (IS_ERR(di))
5346                 ret = PTR_ERR(di);
5347
5348         if (IS_ERR_OR_NULL(di))
5349                 goto out_err;
5350
5351         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
5352 out:
5353         btrfs_free_path(path);
5354         return ret;
5355 out_err:
5356         location->objectid = 0;
5357         goto out;
5358 }
5359
5360 /*
5361  * when we hit a tree root in a directory, the btrfs part of the inode
5362  * needs to be changed to reflect the root directory of the tree root.  This
5363  * is kind of like crossing a mount point.
5364  */
5365 static int fixup_tree_root_location(struct btrfs_root *root,
5366                                     struct inode *dir,
5367                                     struct dentry *dentry,
5368                                     struct btrfs_key *location,
5369                                     struct btrfs_root **sub_root)
5370 {
5371         struct btrfs_path *path;
5372         struct btrfs_root *new_root;
5373         struct btrfs_root_ref *ref;
5374         struct extent_buffer *leaf;
5375         struct btrfs_key key;
5376         int ret;
5377         int err = 0;
5378
5379         path = btrfs_alloc_path();
5380         if (!path) {
5381                 err = -ENOMEM;
5382                 goto out;
5383         }
5384
5385         err = -ENOENT;
5386         key.objectid = BTRFS_I(dir)->root->root_key.objectid;
5387         key.type = BTRFS_ROOT_REF_KEY;
5388         key.offset = location->objectid;
5389
5390         ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key, path,
5391                                 0, 0);
5392         if (ret) {
5393                 if (ret < 0)
5394                         err = ret;
5395                 goto out;
5396         }
5397
5398         leaf = path->nodes[0];
5399         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
5400         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
5401             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
5402                 goto out;
5403
5404         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
5405                                    (unsigned long)(ref + 1),
5406                                    dentry->d_name.len);
5407         if (ret)
5408                 goto out;
5409
5410         btrfs_release_path(path);
5411
5412         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
5413         if (IS_ERR(new_root)) {
5414                 err = PTR_ERR(new_root);
5415                 goto out;
5416         }
5417
5418         *sub_root = new_root;
5419         location->objectid = btrfs_root_dirid(&new_root->root_item);
5420         location->type = BTRFS_INODE_ITEM_KEY;
5421         location->offset = 0;
5422         err = 0;
5423 out:
5424         btrfs_free_path(path);
5425         return err;
5426 }
5427
5428 static void inode_tree_add(struct inode *inode)
5429 {
5430         struct btrfs_root *root = BTRFS_I(inode)->root;
5431         struct btrfs_inode *entry;
5432         struct rb_node **p;
5433         struct rb_node *parent;
5434         struct rb_node *new = &BTRFS_I(inode)->rb_node;
5435         u64 ino = btrfs_ino(inode);
5436
5437         if (inode_unhashed(inode))
5438                 return;
5439         parent = NULL;
5440         spin_lock(&root->inode_lock);
5441         p = &root->inode_tree.rb_node;
5442         while (*p) {
5443                 parent = *p;
5444                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
5445
5446                 if (ino < btrfs_ino(&entry->vfs_inode))
5447                         p = &parent->rb_left;
5448                 else if (ino > btrfs_ino(&entry->vfs_inode))
5449                         p = &parent->rb_right;
5450                 else {
5451                         WARN_ON(!(entry->vfs_inode.i_state &
5452                                   (I_WILL_FREE | I_FREEING)));
5453                         rb_replace_node(parent, new, &root->inode_tree);
5454                         RB_CLEAR_NODE(parent);
5455                         spin_unlock(&root->inode_lock);
5456                         return;
5457                 }
5458         }
5459         rb_link_node(new, parent, p);
5460         rb_insert_color(new, &root->inode_tree);
5461         spin_unlock(&root->inode_lock);
5462 }
5463
5464 static void inode_tree_del(struct inode *inode)
5465 {
5466         struct btrfs_root *root = BTRFS_I(inode)->root;
5467         int empty = 0;
5468
5469         spin_lock(&root->inode_lock);
5470         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
5471                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
5472                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
5473                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5474         }
5475         spin_unlock(&root->inode_lock);
5476
5477         if (empty && btrfs_root_refs(&root->root_item) == 0) {
5478                 synchronize_srcu(&root->fs_info->subvol_srcu);
5479                 spin_lock(&root->inode_lock);
5480                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5481                 spin_unlock(&root->inode_lock);
5482                 if (empty)
5483                         btrfs_add_dead_root(root);
5484         }
5485 }
5486
5487 void btrfs_invalidate_inodes(struct btrfs_root *root)
5488 {
5489         struct rb_node *node;
5490         struct rb_node *prev;
5491         struct btrfs_inode *entry;
5492         struct inode *inode;
5493         u64 objectid = 0;
5494
5495         if (!test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
5496                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
5497
5498         spin_lock(&root->inode_lock);
5499 again:
5500         node = root->inode_tree.rb_node;
5501         prev = NULL;
5502         while (node) {
5503                 prev = node;
5504                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5505
5506                 if (objectid < btrfs_ino(&entry->vfs_inode))
5507                         node = node->rb_left;
5508                 else if (objectid > btrfs_ino(&entry->vfs_inode))
5509                         node = node->rb_right;
5510                 else
5511                         break;
5512         }
5513         if (!node) {
5514                 while (prev) {
5515                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
5516                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
5517                                 node = prev;
5518                                 break;
5519                         }
5520                         prev = rb_next(prev);
5521                 }
5522         }
5523         while (node) {
5524                 entry = rb_entry(node, struct btrfs_inode, rb_node);
5525                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
5526                 inode = igrab(&entry->vfs_inode);
5527                 if (inode) {
5528                         spin_unlock(&root->inode_lock);
5529                         if (atomic_read(&inode->i_count) > 1)
5530                                 d_prune_aliases(inode);
5531                         /*
5532                          * btrfs_drop_inode will have it removed from
5533                          * the inode cache when its usage count
5534                          * hits zero.
5535                          */
5536                         iput(inode);
5537                         cond_resched();
5538                         spin_lock(&root->inode_lock);
5539                         goto again;
5540                 }
5541
5542                 if (cond_resched_lock(&root->inode_lock))
5543                         goto again;
5544
5545                 node = rb_next(node);
5546         }
5547         spin_unlock(&root->inode_lock);
5548 }
5549
5550 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5551 {
5552         struct btrfs_iget_args *args = p;
5553         inode->i_ino = args->location->objectid;
5554         memcpy(&BTRFS_I(inode)->location, args->location,
5555                sizeof(*args->location));
5556         BTRFS_I(inode)->root = args->root;
5557         return 0;
5558 }
5559
5560 static int btrfs_find_actor(struct inode *inode, void *opaque)
5561 {
5562         struct btrfs_iget_args *args = opaque;
5563         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5564                 args->root == BTRFS_I(inode)->root;
5565 }
5566
5567 static struct inode *btrfs_iget_locked(struct super_block *s,
5568                                        struct btrfs_key *location,
5569                                        struct btrfs_root *root)
5570 {
5571         struct inode *inode;
5572         struct btrfs_iget_args args;
5573         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5574
5575         args.location = location;
5576         args.root = root;
5577
5578         inode = iget5_locked(s, hashval, btrfs_find_actor,
5579                              btrfs_init_locked_inode,
5580                              (void *)&args);
5581         return inode;
5582 }
5583
5584 /* Get an inode object given its location and corresponding root.
5585  * Returns in *is_new if the inode was read from disk
5586  */
5587 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5588                          struct btrfs_root *root, int *new)
5589 {
5590         struct inode *inode;
5591
5592         inode = btrfs_iget_locked(s, location, root);
5593         if (!inode)
5594                 return ERR_PTR(-ENOMEM);
5595
5596         if (inode->i_state & I_NEW) {
5597                 btrfs_read_locked_inode(inode);
5598                 if (!is_bad_inode(inode)) {
5599                         inode_tree_add(inode);
5600                         unlock_new_inode(inode);
5601                         if (new)
5602                                 *new = 1;
5603                 } else {
5604                         unlock_new_inode(inode);
5605                         iput(inode);
5606                         inode = ERR_PTR(-ESTALE);
5607                 }
5608         }
5609
5610         return inode;
5611 }
5612
5613 static struct inode *new_simple_dir(struct super_block *s,
5614                                     struct btrfs_key *key,
5615                                     struct btrfs_root *root)
5616 {
5617         struct inode *inode = new_inode(s);
5618
5619         if (!inode)
5620                 return ERR_PTR(-ENOMEM);
5621
5622         BTRFS_I(inode)->root = root;
5623         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5624         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5625
5626         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5627         inode->i_op = &btrfs_dir_ro_inode_operations;
5628         inode->i_fop = &simple_dir_operations;
5629         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5630         inode->i_mtime = current_fs_time(inode->i_sb);
5631         inode->i_atime = inode->i_mtime;
5632         inode->i_ctime = inode->i_mtime;
5633         BTRFS_I(inode)->i_otime = inode->i_mtime;
5634
5635         return inode;
5636 }
5637
5638 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5639 {
5640         struct inode *inode;
5641         struct btrfs_root *root = BTRFS_I(dir)->root;
5642         struct btrfs_root *sub_root = root;
5643         struct btrfs_key location;
5644         int index;
5645         int ret = 0;
5646
5647         if (dentry->d_name.len > BTRFS_NAME_LEN)
5648                 return ERR_PTR(-ENAMETOOLONG);
5649
5650         ret = btrfs_inode_by_name(dir, dentry, &location);
5651         if (ret < 0)
5652                 return ERR_PTR(ret);
5653
5654         if (location.objectid == 0)
5655                 return ERR_PTR(-ENOENT);
5656
5657         if (location.type == BTRFS_INODE_ITEM_KEY) {
5658                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5659                 return inode;
5660         }
5661
5662         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
5663
5664         index = srcu_read_lock(&root->fs_info->subvol_srcu);
5665         ret = fixup_tree_root_location(root, dir, dentry,
5666                                        &location, &sub_root);
5667         if (ret < 0) {
5668                 if (ret != -ENOENT)
5669                         inode = ERR_PTR(ret);
5670                 else
5671                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5672         } else {
5673                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5674         }
5675         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
5676
5677         if (!IS_ERR(inode) && root != sub_root) {
5678                 down_read(&root->fs_info->cleanup_work_sem);
5679                 if (!(inode->i_sb->s_flags & MS_RDONLY))
5680                         ret = btrfs_orphan_cleanup(sub_root);
5681                 up_read(&root->fs_info->cleanup_work_sem);
5682                 if (ret) {
5683                         iput(inode);
5684                         inode = ERR_PTR(ret);
5685                 }
5686         }
5687
5688         return inode;
5689 }
5690
5691 static int btrfs_dentry_delete(const struct dentry *dentry)
5692 {
5693         struct btrfs_root *root;
5694         struct inode *inode = d_inode(dentry);
5695
5696         if (!inode && !IS_ROOT(dentry))
5697                 inode = d_inode(dentry->d_parent);
5698
5699         if (inode) {
5700                 root = BTRFS_I(inode)->root;
5701                 if (btrfs_root_refs(&root->root_item) == 0)
5702                         return 1;
5703
5704                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5705                         return 1;
5706         }
5707         return 0;
5708 }
5709
5710 static void btrfs_dentry_release(struct dentry *dentry)
5711 {
5712         kfree(dentry->d_fsdata);
5713 }
5714
5715 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5716                                    unsigned int flags)
5717 {
5718         struct inode *inode;
5719
5720         inode = btrfs_lookup_dentry(dir, dentry);
5721         if (IS_ERR(inode)) {
5722                 if (PTR_ERR(inode) == -ENOENT)
5723                         inode = NULL;
5724                 else
5725                         return ERR_CAST(inode);
5726         }
5727
5728         return d_splice_alias(inode, dentry);
5729 }
5730
5731 unsigned char btrfs_filetype_table[] = {
5732         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5733 };
5734
5735 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5736 {
5737         struct inode *inode = file_inode(file);
5738         struct btrfs_root *root = BTRFS_I(inode)->root;
5739         struct btrfs_item *item;
5740         struct btrfs_dir_item *di;
5741         struct btrfs_key key;
5742         struct btrfs_key found_key;
5743         struct btrfs_path *path;
5744         struct list_head ins_list;
5745         struct list_head del_list;
5746         int ret;
5747         struct extent_buffer *leaf;
5748         int slot;
5749         unsigned char d_type;
5750         int over = 0;
5751         u32 di_cur;
5752         u32 di_total;
5753         u32 di_len;
5754         int key_type = BTRFS_DIR_INDEX_KEY;
5755         char tmp_name[32];
5756         char *name_ptr;
5757         int name_len;
5758         int is_curr = 0;        /* ctx->pos points to the current index? */
5759         bool emitted;
5760         bool put = false;
5761
5762         /* FIXME, use a real flag for deciding about the key type */
5763         if (root->fs_info->tree_root == root)
5764                 key_type = BTRFS_DIR_ITEM_KEY;
5765
5766         if (!dir_emit_dots(file, ctx))
5767                 return 0;
5768
5769         path = btrfs_alloc_path();
5770         if (!path)
5771                 return -ENOMEM;
5772
5773         path->reada = READA_FORWARD;
5774
5775         if (key_type == BTRFS_DIR_INDEX_KEY) {
5776                 INIT_LIST_HEAD(&ins_list);
5777                 INIT_LIST_HEAD(&del_list);
5778                 put = btrfs_readdir_get_delayed_items(inode, &ins_list,
5779                                                       &del_list);
5780         }
5781
5782         key.type = key_type;
5783         key.offset = ctx->pos;
5784         key.objectid = btrfs_ino(inode);
5785
5786         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5787         if (ret < 0)
5788                 goto err;
5789
5790         emitted = false;
5791         while (1) {
5792                 leaf = path->nodes[0];
5793                 slot = path->slots[0];
5794                 if (slot >= btrfs_header_nritems(leaf)) {
5795                         ret = btrfs_next_leaf(root, path);
5796                         if (ret < 0)
5797                                 goto err;
5798                         else if (ret > 0)
5799                                 break;
5800                         continue;
5801                 }
5802
5803                 item = btrfs_item_nr(slot);
5804                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5805
5806                 if (found_key.objectid != key.objectid)
5807                         break;
5808                 if (found_key.type != key_type)
5809                         break;
5810                 if (found_key.offset < ctx->pos)
5811                         goto next;
5812                 if (key_type == BTRFS_DIR_INDEX_KEY &&
5813                     btrfs_should_delete_dir_index(&del_list,
5814                                                   found_key.offset))
5815                         goto next;
5816
5817                 ctx->pos = found_key.offset;
5818                 is_curr = 1;
5819
5820                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5821                 di_cur = 0;
5822                 di_total = btrfs_item_size(leaf, item);
5823
5824                 while (di_cur < di_total) {
5825                         struct btrfs_key location;
5826
5827                         if (verify_dir_item(root, leaf, di))
5828                                 break;
5829
5830                         name_len = btrfs_dir_name_len(leaf, di);
5831                         if (name_len <= sizeof(tmp_name)) {
5832                                 name_ptr = tmp_name;
5833                         } else {
5834                                 name_ptr = kmalloc(name_len, GFP_KERNEL);
5835                                 if (!name_ptr) {
5836                                         ret = -ENOMEM;
5837                                         goto err;
5838                                 }
5839                         }
5840                         read_extent_buffer(leaf, name_ptr,
5841                                            (unsigned long)(di + 1), name_len);
5842
5843                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
5844                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
5845
5846
5847                         /* is this a reference to our own snapshot? If so
5848                          * skip it.
5849                          *
5850                          * In contrast to old kernels, we insert the snapshot's
5851                          * dir item and dir index after it has been created, so
5852                          * we won't find a reference to our own snapshot. We
5853                          * still keep the following code for backward
5854                          * compatibility.
5855                          */
5856                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
5857                             location.objectid == root->root_key.objectid) {
5858                                 over = 0;
5859                                 goto skip;
5860                         }
5861                         over = !dir_emit(ctx, name_ptr, name_len,
5862                                        location.objectid, d_type);
5863
5864 skip:
5865                         if (name_ptr != tmp_name)
5866                                 kfree(name_ptr);
5867
5868                         if (over)
5869                                 goto nopos;
5870                         emitted = true;
5871                         di_len = btrfs_dir_name_len(leaf, di) +
5872                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
5873                         di_cur += di_len;
5874                         di = (struct btrfs_dir_item *)((char *)di + di_len);
5875                 }
5876 next:
5877                 path->slots[0]++;
5878         }
5879
5880         if (key_type == BTRFS_DIR_INDEX_KEY) {
5881                 if (is_curr)
5882                         ctx->pos++;
5883                 ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list, &emitted);
5884                 if (ret)
5885                         goto nopos;
5886         }
5887
5888         /*
5889          * If we haven't emitted any dir entry, we must not touch ctx->pos as
5890          * it was was set to the termination value in previous call. We assume
5891          * that "." and ".." were emitted if we reach this point and set the
5892          * termination value as well for an empty directory.
5893          */
5894         if (ctx->pos > 2 && !emitted)
5895                 goto nopos;
5896
5897         /* Reached end of directory/root. Bump pos past the last item. */
5898         ctx->pos++;
5899
5900         /*
5901          * Stop new entries from being returned after we return the last
5902          * entry.
5903          *
5904          * New directory entries are assigned a strictly increasing
5905          * offset.  This means that new entries created during readdir
5906          * are *guaranteed* to be seen in the future by that readdir.
5907          * This has broken buggy programs which operate on names as
5908          * they're returned by readdir.  Until we re-use freed offsets
5909          * we have this hack to stop new entries from being returned
5910          * under the assumption that they'll never reach this huge
5911          * offset.
5912          *
5913          * This is being careful not to overflow 32bit loff_t unless the
5914          * last entry requires it because doing so has broken 32bit apps
5915          * in the past.
5916          */
5917         if (key_type == BTRFS_DIR_INDEX_KEY) {
5918                 if (ctx->pos >= INT_MAX)
5919                         ctx->pos = LLONG_MAX;
5920                 else
5921                         ctx->pos = INT_MAX;
5922         }
5923 nopos:
5924         ret = 0;
5925 err:
5926         if (put)
5927                 btrfs_readdir_put_delayed_items(inode, &ins_list, &del_list);
5928         btrfs_free_path(path);
5929         return ret;
5930 }
5931
5932 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
5933 {
5934         struct btrfs_root *root = BTRFS_I(inode)->root;
5935         struct btrfs_trans_handle *trans;
5936         int ret = 0;
5937         bool nolock = false;
5938
5939         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5940                 return 0;
5941
5942         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
5943                 nolock = true;
5944
5945         if (wbc->sync_mode == WB_SYNC_ALL) {
5946                 if (nolock)
5947                         trans = btrfs_join_transaction_nolock(root);
5948                 else
5949                         trans = btrfs_join_transaction(root);
5950                 if (IS_ERR(trans))
5951                         return PTR_ERR(trans);
5952                 ret = btrfs_commit_transaction(trans, root);
5953         }
5954         return ret;
5955 }
5956
5957 /*
5958  * This is somewhat expensive, updating the tree every time the
5959  * inode changes.  But, it is most likely to find the inode in cache.
5960  * FIXME, needs more benchmarking...there are no reasons other than performance
5961  * to keep or drop this code.
5962  */
5963 static int btrfs_dirty_inode(struct inode *inode)
5964 {
5965         struct btrfs_root *root = BTRFS_I(inode)->root;
5966         struct btrfs_trans_handle *trans;
5967         int ret;
5968
5969         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5970                 return 0;
5971
5972         trans = btrfs_join_transaction(root);
5973         if (IS_ERR(trans))
5974                 return PTR_ERR(trans);
5975
5976         ret = btrfs_update_inode(trans, root, inode);
5977         if (ret && ret == -ENOSPC) {
5978                 /* whoops, lets try again with the full transaction */
5979                 btrfs_end_transaction(trans, root);
5980                 trans = btrfs_start_transaction(root, 1);
5981                 if (IS_ERR(trans))
5982                         return PTR_ERR(trans);
5983
5984                 ret = btrfs_update_inode(trans, root, inode);
5985         }
5986         btrfs_end_transaction(trans, root);
5987         if (BTRFS_I(inode)->delayed_node)
5988                 btrfs_balance_delayed_items(root);
5989
5990         return ret;
5991 }
5992
5993 /*
5994  * This is a copy of file_update_time.  We need this so we can return error on
5995  * ENOSPC for updating the inode in the case of file write and mmap writes.
5996  */
5997 static int btrfs_update_time(struct inode *inode, struct timespec *now,
5998                              int flags)
5999 {
6000         struct btrfs_root *root = BTRFS_I(inode)->root;
6001
6002         if (btrfs_root_readonly(root))
6003                 return -EROFS;
6004
6005         if (flags & S_VERSION)
6006                 inode_inc_iversion(inode);
6007         if (flags & S_CTIME)
6008                 inode->i_ctime = *now;
6009         if (flags & S_MTIME)
6010                 inode->i_mtime = *now;
6011         if (flags & S_ATIME)
6012                 inode->i_atime = *now;
6013         return btrfs_dirty_inode(inode);
6014 }
6015
6016 /*
6017  * find the highest existing sequence number in a directory
6018  * and then set the in-memory index_cnt variable to reflect
6019  * free sequence numbers
6020  */
6021 static int btrfs_set_inode_index_count(struct inode *inode)
6022 {
6023         struct btrfs_root *root = BTRFS_I(inode)->root;
6024         struct btrfs_key key, found_key;
6025         struct btrfs_path *path;
6026         struct extent_buffer *leaf;
6027         int ret;
6028
6029         key.objectid = btrfs_ino(inode);
6030         key.type = BTRFS_DIR_INDEX_KEY;
6031         key.offset = (u64)-1;
6032
6033         path = btrfs_alloc_path();
6034         if (!path)
6035                 return -ENOMEM;
6036
6037         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6038         if (ret < 0)
6039                 goto out;
6040         /* FIXME: we should be able to handle this */
6041         if (ret == 0)
6042                 goto out;
6043         ret = 0;
6044
6045         /*
6046          * MAGIC NUMBER EXPLANATION:
6047          * since we search a directory based on f_pos we have to start at 2
6048          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
6049          * else has to start at 2
6050          */
6051         if (path->slots[0] == 0) {
6052                 BTRFS_I(inode)->index_cnt = 2;
6053                 goto out;
6054         }
6055
6056         path->slots[0]--;
6057
6058         leaf = path->nodes[0];
6059         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6060
6061         if (found_key.objectid != btrfs_ino(inode) ||
6062             found_key.type != BTRFS_DIR_INDEX_KEY) {
6063                 BTRFS_I(inode)->index_cnt = 2;
6064                 goto out;
6065         }
6066
6067         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
6068 out:
6069         btrfs_free_path(path);
6070         return ret;
6071 }
6072
6073 /*
6074  * helper to find a free sequence number in a given directory.  This current
6075  * code is very simple, later versions will do smarter things in the btree
6076  */
6077 int btrfs_set_inode_index(struct inode *dir, u64 *index)
6078 {
6079         int ret = 0;
6080
6081         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
6082                 ret = btrfs_inode_delayed_dir_index_count(dir);
6083                 if (ret) {
6084                         ret = btrfs_set_inode_index_count(dir);
6085                         if (ret)
6086                                 return ret;
6087                 }
6088         }
6089
6090         *index = BTRFS_I(dir)->index_cnt;
6091         BTRFS_I(dir)->index_cnt++;
6092
6093         return ret;
6094 }
6095
6096 static int btrfs_insert_inode_locked(struct inode *inode)
6097 {
6098         struct btrfs_iget_args args;
6099         args.location = &BTRFS_I(inode)->location;
6100         args.root = BTRFS_I(inode)->root;
6101
6102         return insert_inode_locked4(inode,
6103                    btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root),
6104                    btrfs_find_actor, &args);
6105 }
6106
6107 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
6108                                      struct btrfs_root *root,
6109                                      struct inode *dir,
6110                                      const char *name, int name_len,
6111                                      u64 ref_objectid, u64 objectid,
6112                                      umode_t mode, u64 *index)
6113 {
6114         struct inode *inode;
6115         struct btrfs_inode_item *inode_item;
6116         struct btrfs_key *location;
6117         struct btrfs_path *path;
6118         struct btrfs_inode_ref *ref;
6119         struct btrfs_key key[2];
6120         u32 sizes[2];
6121         int nitems = name ? 2 : 1;
6122         unsigned long ptr;
6123         int ret;
6124
6125         path = btrfs_alloc_path();
6126         if (!path)
6127                 return ERR_PTR(-ENOMEM);
6128
6129         inode = new_inode(root->fs_info->sb);
6130         if (!inode) {
6131                 btrfs_free_path(path);
6132                 return ERR_PTR(-ENOMEM);
6133         }
6134
6135         /*
6136          * O_TMPFILE, set link count to 0, so that after this point,
6137          * we fill in an inode item with the correct link count.
6138          */
6139         if (!name)
6140                 set_nlink(inode, 0);
6141
6142         /*
6143          * we have to initialize this early, so we can reclaim the inode
6144          * number if we fail afterwards in this function.
6145          */
6146         inode->i_ino = objectid;
6147
6148         if (dir && name) {
6149                 trace_btrfs_inode_request(dir);
6150
6151                 ret = btrfs_set_inode_index(dir, index);
6152                 if (ret) {
6153                         btrfs_free_path(path);
6154                         iput(inode);
6155                         return ERR_PTR(ret);
6156                 }
6157         } else if (dir) {
6158                 *index = 0;
6159         }
6160         /*
6161          * index_cnt is ignored for everything but a dir,
6162          * btrfs_get_inode_index_count has an explanation for the magic
6163          * number
6164          */
6165         BTRFS_I(inode)->index_cnt = 2;
6166         BTRFS_I(inode)->dir_index = *index;
6167         BTRFS_I(inode)->root = root;
6168         BTRFS_I(inode)->generation = trans->transid;
6169         inode->i_generation = BTRFS_I(inode)->generation;
6170
6171         /*
6172          * We could have gotten an inode number from somebody who was fsynced
6173          * and then removed in this same transaction, so let's just set full
6174          * sync since it will be a full sync anyway and this will blow away the
6175          * old info in the log.
6176          */
6177         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
6178
6179         key[0].objectid = objectid;
6180         key[0].type = BTRFS_INODE_ITEM_KEY;
6181         key[0].offset = 0;
6182
6183         sizes[0] = sizeof(struct btrfs_inode_item);
6184
6185         if (name) {
6186                 /*
6187                  * Start new inodes with an inode_ref. This is slightly more
6188                  * efficient for small numbers of hard links since they will
6189                  * be packed into one item. Extended refs will kick in if we
6190                  * add more hard links than can fit in the ref item.
6191                  */
6192                 key[1].objectid = objectid;
6193                 key[1].type = BTRFS_INODE_REF_KEY;
6194                 key[1].offset = ref_objectid;
6195
6196                 sizes[1] = name_len + sizeof(*ref);
6197         }
6198
6199         location = &BTRFS_I(inode)->location;
6200         location->objectid = objectid;
6201         location->offset = 0;
6202         location->type = BTRFS_INODE_ITEM_KEY;
6203
6204         ret = btrfs_insert_inode_locked(inode);
6205         if (ret < 0)
6206                 goto fail;
6207
6208         path->leave_spinning = 1;
6209         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
6210         if (ret != 0)
6211                 goto fail_unlock;
6212
6213         inode_init_owner(inode, dir, mode);
6214         inode_set_bytes(inode, 0);
6215
6216         inode->i_mtime = current_fs_time(inode->i_sb);
6217         inode->i_atime = inode->i_mtime;
6218         inode->i_ctime = inode->i_mtime;
6219         BTRFS_I(inode)->i_otime = inode->i_mtime;
6220
6221         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
6222                                   struct btrfs_inode_item);
6223         memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
6224                              sizeof(*inode_item));
6225         fill_inode_item(trans, path->nodes[0], inode_item, inode);
6226
6227         if (name) {
6228                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
6229                                      struct btrfs_inode_ref);
6230                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
6231                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
6232                 ptr = (unsigned long)(ref + 1);
6233                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
6234         }
6235
6236         btrfs_mark_buffer_dirty(path->nodes[0]);
6237         btrfs_free_path(path);
6238
6239         btrfs_inherit_iflags(inode, dir);
6240
6241         if (S_ISREG(mode)) {
6242                 if (btrfs_test_opt(root, NODATASUM))
6243                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
6244                 if (btrfs_test_opt(root, NODATACOW))
6245                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
6246                                 BTRFS_INODE_NODATASUM;
6247         }
6248
6249         inode_tree_add(inode);
6250
6251         trace_btrfs_inode_new(inode);
6252         btrfs_set_inode_last_trans(trans, inode);
6253
6254         btrfs_update_root_times(trans, root);
6255
6256         ret = btrfs_inode_inherit_props(trans, inode, dir);
6257         if (ret)
6258                 btrfs_err(root->fs_info,
6259                           "error inheriting props for ino %llu (root %llu): %d",
6260                           btrfs_ino(inode), root->root_key.objectid, ret);
6261
6262         return inode;
6263
6264 fail_unlock:
6265         unlock_new_inode(inode);
6266 fail:
6267         if (dir && name)
6268                 BTRFS_I(dir)->index_cnt--;
6269         btrfs_free_path(path);
6270         iput(inode);
6271         return ERR_PTR(ret);
6272 }
6273
6274 static inline u8 btrfs_inode_type(struct inode *inode)
6275 {
6276         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
6277 }
6278
6279 /*
6280  * utility function to add 'inode' into 'parent_inode' with
6281  * a give name and a given sequence number.
6282  * if 'add_backref' is true, also insert a backref from the
6283  * inode to the parent directory.
6284  */
6285 int btrfs_add_link(struct btrfs_trans_handle *trans,
6286                    struct inode *parent_inode, struct inode *inode,
6287                    const char *name, int name_len, int add_backref, u64 index)
6288 {
6289         int ret = 0;
6290         struct btrfs_key key;
6291         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
6292         u64 ino = btrfs_ino(inode);
6293         u64 parent_ino = btrfs_ino(parent_inode);
6294
6295         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6296                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
6297         } else {
6298                 key.objectid = ino;
6299                 key.type = BTRFS_INODE_ITEM_KEY;
6300                 key.offset = 0;
6301         }
6302
6303         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6304                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
6305                                          key.objectid, root->root_key.objectid,
6306                                          parent_ino, index, name, name_len);
6307         } else if (add_backref) {
6308                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
6309                                              parent_ino, index);
6310         }
6311
6312         /* Nothing to clean up yet */
6313         if (ret)
6314                 return ret;
6315
6316         ret = btrfs_insert_dir_item(trans, root, name, name_len,
6317                                     parent_inode, &key,
6318                                     btrfs_inode_type(inode), index);
6319         if (ret == -EEXIST || ret == -EOVERFLOW)
6320                 goto fail_dir_item;
6321         else if (ret) {
6322                 btrfs_abort_transaction(trans, root, ret);
6323                 return ret;
6324         }
6325
6326         btrfs_i_size_write(parent_inode, parent_inode->i_size +
6327                            name_len * 2);
6328         inode_inc_iversion(parent_inode);
6329         parent_inode->i_mtime = parent_inode->i_ctime =
6330                 current_fs_time(parent_inode->i_sb);
6331         ret = btrfs_update_inode(trans, root, parent_inode);
6332         if (ret)
6333                 btrfs_abort_transaction(trans, root, ret);
6334         return ret;
6335
6336 fail_dir_item:
6337         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
6338                 u64 local_index;
6339                 int err;
6340                 err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
6341                                  key.objectid, root->root_key.objectid,
6342                                  parent_ino, &local_index, name, name_len);
6343
6344         } else if (add_backref) {
6345                 u64 local_index;
6346                 int err;
6347
6348                 err = btrfs_del_inode_ref(trans, root, name, name_len,
6349                                           ino, parent_ino, &local_index);
6350         }
6351         return ret;
6352 }
6353
6354 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
6355                             struct inode *dir, struct dentry *dentry,
6356                             struct inode *inode, int backref, u64 index)
6357 {
6358         int err = btrfs_add_link(trans, dir, inode,
6359                                  dentry->d_name.name, dentry->d_name.len,
6360                                  backref, index);
6361         if (err > 0)
6362                 err = -EEXIST;
6363         return err;
6364 }
6365
6366 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
6367                         umode_t mode, dev_t rdev)
6368 {
6369         struct btrfs_trans_handle *trans;
6370         struct btrfs_root *root = BTRFS_I(dir)->root;
6371         struct inode *inode = NULL;
6372         int err;
6373         int drop_inode = 0;
6374         u64 objectid;
6375         u64 index = 0;
6376
6377         /*
6378          * 2 for inode item and ref
6379          * 2 for dir items
6380          * 1 for xattr if selinux is on
6381          */
6382         trans = btrfs_start_transaction(root, 5);
6383         if (IS_ERR(trans))
6384                 return PTR_ERR(trans);
6385
6386         err = btrfs_find_free_ino(root, &objectid);
6387         if (err)
6388                 goto out_unlock;
6389
6390         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6391                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6392                                 mode, &index);
6393         if (IS_ERR(inode)) {
6394                 err = PTR_ERR(inode);
6395                 goto out_unlock;
6396         }
6397
6398         /*
6399         * If the active LSM wants to access the inode during
6400         * d_instantiate it needs these. Smack checks to see
6401         * if the filesystem supports xattrs by looking at the
6402         * ops vector.
6403         */
6404         inode->i_op = &btrfs_special_inode_operations;
6405         init_special_inode(inode, inode->i_mode, rdev);
6406
6407         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6408         if (err)
6409                 goto out_unlock_inode;
6410
6411         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6412         if (err) {
6413                 goto out_unlock_inode;
6414         } else {
6415                 btrfs_update_inode(trans, root, inode);
6416                 unlock_new_inode(inode);
6417                 d_instantiate(dentry, inode);
6418         }
6419
6420 out_unlock:
6421         btrfs_end_transaction(trans, root);
6422         btrfs_balance_delayed_items(root);
6423         btrfs_btree_balance_dirty(root);
6424         if (drop_inode) {
6425                 inode_dec_link_count(inode);
6426                 iput(inode);
6427         }
6428         return err;
6429
6430 out_unlock_inode:
6431         drop_inode = 1;
6432         unlock_new_inode(inode);
6433         goto out_unlock;
6434
6435 }
6436
6437 static int btrfs_create(struct inode *dir, struct dentry *dentry,
6438                         umode_t mode, bool excl)
6439 {
6440         struct btrfs_trans_handle *trans;
6441         struct btrfs_root *root = BTRFS_I(dir)->root;
6442         struct inode *inode = NULL;
6443         int drop_inode_on_err = 0;
6444         int err;
6445         u64 objectid;
6446         u64 index = 0;
6447
6448         /*
6449          * 2 for inode item and ref
6450          * 2 for dir items
6451          * 1 for xattr if selinux is on
6452          */
6453         trans = btrfs_start_transaction(root, 5);
6454         if (IS_ERR(trans))
6455                 return PTR_ERR(trans);
6456
6457         err = btrfs_find_free_ino(root, &objectid);
6458         if (err)
6459                 goto out_unlock;
6460
6461         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6462                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6463                                 mode, &index);
6464         if (IS_ERR(inode)) {
6465                 err = PTR_ERR(inode);
6466                 goto out_unlock;
6467         }
6468         drop_inode_on_err = 1;
6469         /*
6470         * If the active LSM wants to access the inode during
6471         * d_instantiate it needs these. Smack checks to see
6472         * if the filesystem supports xattrs by looking at the
6473         * ops vector.
6474         */
6475         inode->i_fop = &btrfs_file_operations;
6476         inode->i_op = &btrfs_file_inode_operations;
6477         inode->i_mapping->a_ops = &btrfs_aops;
6478
6479         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6480         if (err)
6481                 goto out_unlock_inode;
6482
6483         err = btrfs_update_inode(trans, root, inode);
6484         if (err)
6485                 goto out_unlock_inode;
6486
6487         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
6488         if (err)
6489                 goto out_unlock_inode;
6490
6491         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
6492         unlock_new_inode(inode);
6493         d_instantiate(dentry, inode);
6494
6495 out_unlock:
6496         btrfs_end_transaction(trans, root);
6497         if (err && drop_inode_on_err) {
6498                 inode_dec_link_count(inode);
6499                 iput(inode);
6500         }
6501         btrfs_balance_delayed_items(root);
6502         btrfs_btree_balance_dirty(root);
6503         return err;
6504
6505 out_unlock_inode:
6506         unlock_new_inode(inode);
6507         goto out_unlock;
6508
6509 }
6510
6511 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
6512                       struct dentry *dentry)
6513 {
6514         struct btrfs_trans_handle *trans = NULL;
6515         struct btrfs_root *root = BTRFS_I(dir)->root;
6516         struct inode *inode = d_inode(old_dentry);
6517         u64 index;
6518         int err;
6519         int drop_inode = 0;
6520
6521         /* do not allow sys_link's with other subvols of the same device */
6522         if (root->objectid != BTRFS_I(inode)->root->objectid)
6523                 return -EXDEV;
6524
6525         if (inode->i_nlink >= BTRFS_LINK_MAX)
6526                 return -EMLINK;
6527
6528         err = btrfs_set_inode_index(dir, &index);
6529         if (err)
6530                 goto fail;
6531
6532         /*
6533          * 2 items for inode and inode ref
6534          * 2 items for dir items
6535          * 1 item for parent inode
6536          */
6537         trans = btrfs_start_transaction(root, 5);
6538         if (IS_ERR(trans)) {
6539                 err = PTR_ERR(trans);
6540                 trans = NULL;
6541                 goto fail;
6542         }
6543
6544         /* There are several dir indexes for this inode, clear the cache. */
6545         BTRFS_I(inode)->dir_index = 0ULL;
6546         inc_nlink(inode);
6547         inode_inc_iversion(inode);
6548         inode->i_ctime = current_fs_time(inode->i_sb);
6549         ihold(inode);
6550         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
6551
6552         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
6553
6554         if (err) {
6555                 drop_inode = 1;
6556         } else {
6557                 struct dentry *parent = dentry->d_parent;
6558                 err = btrfs_update_inode(trans, root, inode);
6559                 if (err)
6560                         goto fail;
6561                 if (inode->i_nlink == 1) {
6562                         /*
6563                          * If new hard link count is 1, it's a file created
6564                          * with open(2) O_TMPFILE flag.
6565                          */
6566                         err = btrfs_orphan_del(trans, inode);
6567                         if (err)
6568                                 goto fail;
6569                 }
6570                 d_instantiate(dentry, inode);
6571                 btrfs_log_new_name(trans, inode, NULL, parent);
6572         }
6573
6574         btrfs_balance_delayed_items(root);
6575 fail:
6576         if (trans)
6577                 btrfs_end_transaction(trans, root);
6578         if (drop_inode) {
6579                 inode_dec_link_count(inode);
6580                 iput(inode);
6581         }
6582         btrfs_btree_balance_dirty(root);
6583         return err;
6584 }
6585
6586 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6587 {
6588         struct inode *inode = NULL;
6589         struct btrfs_trans_handle *trans;
6590         struct btrfs_root *root = BTRFS_I(dir)->root;
6591         int err = 0;
6592         int drop_on_err = 0;
6593         u64 objectid = 0;
6594         u64 index = 0;
6595
6596         /*
6597          * 2 items for inode and ref
6598          * 2 items for dir items
6599          * 1 for xattr if selinux is on
6600          */
6601         trans = btrfs_start_transaction(root, 5);
6602         if (IS_ERR(trans))
6603                 return PTR_ERR(trans);
6604
6605         err = btrfs_find_free_ino(root, &objectid);
6606         if (err)
6607                 goto out_fail;
6608
6609         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6610                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6611                                 S_IFDIR | mode, &index);
6612         if (IS_ERR(inode)) {
6613                 err = PTR_ERR(inode);
6614                 goto out_fail;
6615         }
6616
6617         drop_on_err = 1;
6618         /* these must be set before we unlock the inode */
6619         inode->i_op = &btrfs_dir_inode_operations;
6620         inode->i_fop = &btrfs_dir_file_operations;
6621
6622         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6623         if (err)
6624                 goto out_fail_inode;
6625
6626         btrfs_i_size_write(inode, 0);
6627         err = btrfs_update_inode(trans, root, inode);
6628         if (err)
6629                 goto out_fail_inode;
6630
6631         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
6632                              dentry->d_name.len, 0, index);
6633         if (err)
6634                 goto out_fail_inode;
6635
6636         d_instantiate(dentry, inode);
6637         /*
6638          * mkdir is special.  We're unlocking after we call d_instantiate
6639          * to avoid a race with nfsd calling d_instantiate.
6640          */
6641         unlock_new_inode(inode);
6642         drop_on_err = 0;
6643
6644 out_fail:
6645         btrfs_end_transaction(trans, root);
6646         if (drop_on_err) {
6647                 inode_dec_link_count(inode);
6648                 iput(inode);
6649         }
6650         btrfs_balance_delayed_items(root);
6651         btrfs_btree_balance_dirty(root);
6652         return err;
6653
6654 out_fail_inode:
6655         unlock_new_inode(inode);
6656         goto out_fail;
6657 }
6658
6659 /* Find next extent map of a given extent map, caller needs to ensure locks */
6660 static struct extent_map *next_extent_map(struct extent_map *em)
6661 {
6662         struct rb_node *next;
6663
6664         next = rb_next(&em->rb_node);
6665         if (!next)
6666                 return NULL;
6667         return container_of(next, struct extent_map, rb_node);
6668 }
6669
6670 static struct extent_map *prev_extent_map(struct extent_map *em)
6671 {
6672         struct rb_node *prev;
6673
6674         prev = rb_prev(&em->rb_node);
6675         if (!prev)
6676                 return NULL;
6677         return container_of(prev, struct extent_map, rb_node);
6678 }
6679
6680 /* helper for btfs_get_extent.  Given an existing extent in the tree,
6681  * the existing extent is the nearest extent to map_start,
6682  * and an extent that you want to insert, deal with overlap and insert
6683  * the best fitted new extent into the tree.
6684  */
6685 static int merge_extent_mapping(struct extent_map_tree *em_tree,
6686                                 struct extent_map *existing,
6687                                 struct extent_map *em,
6688                                 u64 map_start)
6689 {
6690         struct extent_map *prev;
6691         struct extent_map *next;
6692         u64 start;
6693         u64 end;
6694         u64 start_diff;
6695
6696         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
6697
6698         if (existing->start > map_start) {
6699                 next = existing;
6700                 prev = prev_extent_map(next);
6701         } else {
6702                 prev = existing;
6703                 next = next_extent_map(prev);
6704         }
6705
6706         start = prev ? extent_map_end(prev) : em->start;
6707         start = max_t(u64, start, em->start);
6708         end = next ? next->start : extent_map_end(em);
6709         end = min_t(u64, end, extent_map_end(em));
6710         start_diff = start - em->start;
6711         em->start = start;
6712         em->len = end - start;
6713         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
6714             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
6715                 em->block_start += start_diff;
6716                 em->block_len -= start_diff;
6717         }
6718         return add_extent_mapping(em_tree, em, 0);
6719 }
6720
6721 static noinline int uncompress_inline(struct btrfs_path *path,
6722                                       struct page *page,
6723                                       size_t pg_offset, u64 extent_offset,
6724                                       struct btrfs_file_extent_item *item)
6725 {
6726         int ret;
6727         struct extent_buffer *leaf = path->nodes[0];
6728         char *tmp;
6729         size_t max_size;
6730         unsigned long inline_size;
6731         unsigned long ptr;
6732         int compress_type;
6733
6734         WARN_ON(pg_offset != 0);
6735         compress_type = btrfs_file_extent_compression(leaf, item);
6736         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6737         inline_size = btrfs_file_extent_inline_item_len(leaf,
6738                                         btrfs_item_nr(path->slots[0]));
6739         tmp = kmalloc(inline_size, GFP_NOFS);
6740         if (!tmp)
6741                 return -ENOMEM;
6742         ptr = btrfs_file_extent_inline_start(item);
6743
6744         read_extent_buffer(leaf, tmp, ptr, inline_size);
6745
6746         max_size = min_t(unsigned long, PAGE_SIZE, max_size);
6747         ret = btrfs_decompress(compress_type, tmp, page,
6748                                extent_offset, inline_size, max_size);
6749         kfree(tmp);
6750         return ret;
6751 }
6752
6753 /*
6754  * a bit scary, this does extent mapping from logical file offset to the disk.
6755  * the ugly parts come from merging extents from the disk with the in-ram
6756  * representation.  This gets more complex because of the data=ordered code,
6757  * where the in-ram extents might be locked pending data=ordered completion.
6758  *
6759  * This also copies inline extents directly into the page.
6760  */
6761
6762 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
6763                                     size_t pg_offset, u64 start, u64 len,
6764                                     int create)
6765 {
6766         int ret;
6767         int err = 0;
6768         u64 extent_start = 0;
6769         u64 extent_end = 0;
6770         u64 objectid = btrfs_ino(inode);
6771         u32 found_type;
6772         struct btrfs_path *path = NULL;
6773         struct btrfs_root *root = BTRFS_I(inode)->root;
6774         struct btrfs_file_extent_item *item;
6775         struct extent_buffer *leaf;
6776         struct btrfs_key found_key;
6777         struct extent_map *em = NULL;
6778         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
6779         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6780         struct btrfs_trans_handle *trans = NULL;
6781         const bool new_inline = !page || create;
6782
6783 again:
6784         read_lock(&em_tree->lock);
6785         em = lookup_extent_mapping(em_tree, start, len);
6786         if (em)
6787                 em->bdev = root->fs_info->fs_devices->latest_bdev;
6788         read_unlock(&em_tree->lock);
6789
6790         if (em) {
6791                 if (em->start > start || em->start + em->len <= start)
6792                         free_extent_map(em);
6793                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6794                         free_extent_map(em);
6795                 else
6796                         goto out;
6797         }
6798         em = alloc_extent_map();
6799         if (!em) {
6800                 err = -ENOMEM;
6801                 goto out;
6802         }
6803         em->bdev = root->fs_info->fs_devices->latest_bdev;
6804         em->start = EXTENT_MAP_HOLE;
6805         em->orig_start = EXTENT_MAP_HOLE;
6806         em->len = (u64)-1;
6807         em->block_len = (u64)-1;
6808
6809         if (!path) {
6810                 path = btrfs_alloc_path();
6811                 if (!path) {
6812                         err = -ENOMEM;
6813                         goto out;
6814                 }
6815                 /*
6816                  * Chances are we'll be called again, so go ahead and do
6817                  * readahead
6818                  */
6819                 path->reada = READA_FORWARD;
6820         }
6821
6822         ret = btrfs_lookup_file_extent(trans, root, path,
6823                                        objectid, start, trans != NULL);
6824         if (ret < 0) {
6825                 err = ret;
6826                 goto out;
6827         }
6828
6829         if (ret != 0) {
6830                 if (path->slots[0] == 0)
6831                         goto not_found;
6832                 path->slots[0]--;
6833         }
6834
6835         leaf = path->nodes[0];
6836         item = btrfs_item_ptr(leaf, path->slots[0],
6837                               struct btrfs_file_extent_item);
6838         /* are we inside the extent that was found? */
6839         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6840         found_type = found_key.type;
6841         if (found_key.objectid != objectid ||
6842             found_type != BTRFS_EXTENT_DATA_KEY) {
6843                 /*
6844                  * If we backup past the first extent we want to move forward
6845                  * and see if there is an extent in front of us, otherwise we'll
6846                  * say there is a hole for our whole search range which can
6847                  * cause problems.
6848                  */
6849                 extent_end = start;
6850                 goto next;
6851         }
6852
6853         found_type = btrfs_file_extent_type(leaf, item);
6854         extent_start = found_key.offset;
6855         if (found_type == BTRFS_FILE_EXTENT_REG ||
6856             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6857                 extent_end = extent_start +
6858                        btrfs_file_extent_num_bytes(leaf, item);
6859         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6860                 size_t size;
6861                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6862                 extent_end = ALIGN(extent_start + size, root->sectorsize);
6863         }
6864 next:
6865         if (start >= extent_end) {
6866                 path->slots[0]++;
6867                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6868                         ret = btrfs_next_leaf(root, path);
6869                         if (ret < 0) {
6870                                 err = ret;
6871                                 goto out;
6872                         }
6873                         if (ret > 0)
6874                                 goto not_found;
6875                         leaf = path->nodes[0];
6876                 }
6877                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6878                 if (found_key.objectid != objectid ||
6879                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6880                         goto not_found;
6881                 if (start + len <= found_key.offset)
6882                         goto not_found;
6883                 if (start > found_key.offset)
6884                         goto next;
6885                 em->start = start;
6886                 em->orig_start = start;
6887                 em->len = found_key.offset - start;
6888                 goto not_found_em;
6889         }
6890
6891         btrfs_extent_item_to_extent_map(inode, path, item, new_inline, em);
6892
6893         if (found_type == BTRFS_FILE_EXTENT_REG ||
6894             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6895                 goto insert;
6896         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6897                 unsigned long ptr;
6898                 char *map;
6899                 size_t size;
6900                 size_t extent_offset;
6901                 size_t copy_size;
6902
6903                 if (new_inline)
6904                         goto out;
6905
6906                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6907                 extent_offset = page_offset(page) + pg_offset - extent_start;
6908                 copy_size = min_t(u64, PAGE_SIZE - pg_offset,
6909                                   size - extent_offset);
6910                 em->start = extent_start + extent_offset;
6911                 em->len = ALIGN(copy_size, root->sectorsize);
6912                 em->orig_block_len = em->len;
6913                 em->orig_start = em->start;
6914                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6915                 if (create == 0 && !PageUptodate(page)) {
6916                         if (btrfs_file_extent_compression(leaf, item) !=
6917                             BTRFS_COMPRESS_NONE) {
6918                                 ret = uncompress_inline(path, page, pg_offset,
6919                                                         extent_offset, item);
6920                                 if (ret) {
6921                                         err = ret;
6922                                         goto out;
6923                                 }
6924                         } else {
6925                                 map = kmap(page);
6926                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6927                                                    copy_size);
6928                                 if (pg_offset + copy_size < PAGE_SIZE) {
6929                                         memset(map + pg_offset + copy_size, 0,
6930                                                PAGE_SIZE - pg_offset -
6931                                                copy_size);
6932                                 }
6933                                 kunmap(page);
6934                         }
6935                         flush_dcache_page(page);
6936                 } else if (create && PageUptodate(page)) {
6937                         BUG();
6938                         if (!trans) {
6939                                 kunmap(page);
6940                                 free_extent_map(em);
6941                                 em = NULL;
6942
6943                                 btrfs_release_path(path);
6944                                 trans = btrfs_join_transaction(root);
6945
6946                                 if (IS_ERR(trans))
6947                                         return ERR_CAST(trans);
6948                                 goto again;
6949                         }
6950                         map = kmap(page);
6951                         write_extent_buffer(leaf, map + pg_offset, ptr,
6952                                             copy_size);
6953                         kunmap(page);
6954                         btrfs_mark_buffer_dirty(leaf);
6955                 }
6956                 set_extent_uptodate(io_tree, em->start,
6957                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6958                 goto insert;
6959         }
6960 not_found:
6961         em->start = start;
6962         em->orig_start = start;
6963         em->len = len;
6964 not_found_em:
6965         em->block_start = EXTENT_MAP_HOLE;
6966         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
6967 insert:
6968         btrfs_release_path(path);
6969         if (em->start > start || extent_map_end(em) <= start) {
6970                 btrfs_err(root->fs_info, "bad extent! em: [%llu %llu] passed [%llu %llu]",
6971                         em->start, em->len, start, len);
6972                 err = -EIO;
6973                 goto out;
6974         }
6975
6976         err = 0;
6977         write_lock(&em_tree->lock);
6978         ret = add_extent_mapping(em_tree, em, 0);
6979         /* it is possible that someone inserted the extent into the tree
6980          * while we had the lock dropped.  It is also possible that
6981          * an overlapping map exists in the tree
6982          */
6983         if (ret == -EEXIST) {
6984                 struct extent_map *existing;
6985
6986                 ret = 0;
6987
6988                 existing = search_extent_mapping(em_tree, start, len);
6989                 /*
6990                  * existing will always be non-NULL, since there must be
6991                  * extent causing the -EEXIST.
6992                  */
6993                 if (existing->start == em->start &&
6994                     extent_map_end(existing) == extent_map_end(em) &&
6995                     em->block_start == existing->block_start) {
6996                         /*
6997                          * these two extents are the same, it happens
6998                          * with inlines especially
6999                          */
7000                         free_extent_map(em);
7001                         em = existing;
7002                         err = 0;
7003
7004                 } else if (start >= extent_map_end(existing) ||
7005                     start <= existing->start) {
7006                         /*
7007                          * The existing extent map is the one nearest to
7008                          * the [start, start + len) range which overlaps
7009                          */
7010                         err = merge_extent_mapping(em_tree, existing,
7011                                                    em, start);
7012                         free_extent_map(existing);
7013                         if (err) {
7014                                 free_extent_map(em);
7015                                 em = NULL;
7016                         }
7017                 } else {
7018                         free_extent_map(em);
7019                         em = existing;
7020                         err = 0;
7021                 }
7022         }
7023         write_unlock(&em_tree->lock);
7024 out:
7025
7026         trace_btrfs_get_extent(root, em);
7027
7028         btrfs_free_path(path);
7029         if (trans) {
7030                 ret = btrfs_end_transaction(trans, root);
7031                 if (!err)
7032                         err = ret;
7033         }
7034         if (err) {
7035                 free_extent_map(em);
7036                 return ERR_PTR(err);
7037         }
7038         BUG_ON(!em); /* Error is always set */
7039         return em;
7040 }
7041
7042 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
7043                                            size_t pg_offset, u64 start, u64 len,
7044                                            int create)
7045 {
7046         struct extent_map *em;
7047         struct extent_map *hole_em = NULL;
7048         u64 range_start = start;
7049         u64 end;
7050         u64 found;
7051         u64 found_end;
7052         int err = 0;
7053
7054         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
7055         if (IS_ERR(em))
7056                 return em;
7057         if (em) {
7058                 /*
7059                  * if our em maps to
7060                  * -  a hole or
7061                  * -  a pre-alloc extent,
7062                  * there might actually be delalloc bytes behind it.
7063                  */
7064                 if (em->block_start != EXTENT_MAP_HOLE &&
7065                     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7066                         return em;
7067                 else
7068                         hole_em = em;
7069         }
7070
7071         /* check to see if we've wrapped (len == -1 or similar) */
7072         end = start + len;
7073         if (end < start)
7074                 end = (u64)-1;
7075         else
7076                 end -= 1;
7077
7078         em = NULL;
7079
7080         /* ok, we didn't find anything, lets look for delalloc */
7081         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
7082                                  end, len, EXTENT_DELALLOC, 1);
7083         found_end = range_start + found;
7084         if (found_end < range_start)
7085                 found_end = (u64)-1;
7086
7087         /*
7088          * we didn't find anything useful, return
7089          * the original results from get_extent()
7090          */
7091         if (range_start > end || found_end <= start) {
7092                 em = hole_em;
7093                 hole_em = NULL;
7094                 goto out;
7095         }
7096
7097         /* adjust the range_start to make sure it doesn't
7098          * go backwards from the start they passed in
7099          */
7100         range_start = max(start, range_start);
7101         found = found_end - range_start;
7102
7103         if (found > 0) {
7104                 u64 hole_start = start;
7105                 u64 hole_len = len;
7106
7107                 em = alloc_extent_map();
7108                 if (!em) {
7109                         err = -ENOMEM;
7110                         goto out;
7111                 }
7112                 /*
7113                  * when btrfs_get_extent can't find anything it
7114                  * returns one huge hole
7115                  *
7116                  * make sure what it found really fits our range, and
7117                  * adjust to make sure it is based on the start from
7118                  * the caller
7119                  */
7120                 if (hole_em) {
7121                         u64 calc_end = extent_map_end(hole_em);
7122
7123                         if (calc_end <= start || (hole_em->start > end)) {
7124                                 free_extent_map(hole_em);
7125                                 hole_em = NULL;
7126                         } else {
7127                                 hole_start = max(hole_em->start, start);
7128                                 hole_len = calc_end - hole_start;
7129                         }
7130                 }
7131                 em->bdev = NULL;
7132                 if (hole_em && range_start > hole_start) {
7133                         /* our hole starts before our delalloc, so we
7134                          * have to return just the parts of the hole
7135                          * that go until  the delalloc starts
7136                          */
7137                         em->len = min(hole_len,
7138                                       range_start - hole_start);
7139                         em->start = hole_start;
7140                         em->orig_start = hole_start;
7141                         /*
7142                          * don't adjust block start at all,
7143                          * it is fixed at EXTENT_MAP_HOLE
7144                          */
7145                         em->block_start = hole_em->block_start;
7146                         em->block_len = hole_len;
7147                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
7148                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
7149                 } else {
7150                         em->start = range_start;
7151                         em->len = found;
7152                         em->orig_start = range_start;
7153                         em->block_start = EXTENT_MAP_DELALLOC;
7154                         em->block_len = found;
7155                 }
7156         } else if (hole_em) {
7157                 return hole_em;
7158         }
7159 out:
7160
7161         free_extent_map(hole_em);
7162         if (err) {
7163                 free_extent_map(em);
7164                 return ERR_PTR(err);
7165         }
7166         return em;
7167 }
7168
7169 static struct extent_map *btrfs_create_dio_extent(struct inode *inode,
7170                                                   const u64 start,
7171                                                   const u64 len,
7172                                                   const u64 orig_start,
7173                                                   const u64 block_start,
7174                                                   const u64 block_len,
7175                                                   const u64 orig_block_len,
7176                                                   const u64 ram_bytes,
7177                                                   const int type)
7178 {
7179         struct extent_map *em = NULL;
7180         int ret;
7181
7182         down_read(&BTRFS_I(inode)->dio_sem);
7183         if (type != BTRFS_ORDERED_NOCOW) {
7184                 em = create_pinned_em(inode, start, len, orig_start,
7185                                       block_start, block_len, orig_block_len,
7186                                       ram_bytes, type);
7187                 if (IS_ERR(em))
7188                         goto out;
7189         }
7190         ret = btrfs_add_ordered_extent_dio(inode, start, block_start,
7191                                            len, block_len, type);
7192         if (ret) {
7193                 if (em) {
7194                         free_extent_map(em);
7195                         btrfs_drop_extent_cache(inode, start,
7196                                                 start + len - 1, 0);
7197                 }
7198                 em = ERR_PTR(ret);
7199         }
7200  out:
7201         up_read(&BTRFS_I(inode)->dio_sem);
7202
7203         return em;
7204 }
7205
7206 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
7207                                                   u64 start, u64 len)
7208 {
7209         struct btrfs_root *root = BTRFS_I(inode)->root;
7210         struct extent_map *em;
7211         struct btrfs_key ins;
7212         u64 alloc_hint;
7213         int ret;
7214
7215         alloc_hint = get_extent_allocation_hint(inode, start, len);
7216         ret = btrfs_reserve_extent(root, len, root->sectorsize, 0,
7217                                    alloc_hint, &ins, 1, 1);
7218         if (ret)
7219                 return ERR_PTR(ret);
7220
7221         em = btrfs_create_dio_extent(inode, start, ins.offset, start,
7222                                      ins.objectid, ins.offset, ins.offset,
7223                                      ins.offset, 0);
7224         btrfs_dec_block_group_reservations(root->fs_info, ins.objectid);
7225         if (IS_ERR(em))
7226                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
7227
7228         return em;
7229 }
7230
7231 /*
7232  * returns 1 when the nocow is safe, < 1 on error, 0 if the
7233  * block must be cow'd
7234  */
7235 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
7236                               u64 *orig_start, u64 *orig_block_len,
7237                               u64 *ram_bytes)
7238 {
7239         struct btrfs_trans_handle *trans;
7240         struct btrfs_path *path;
7241         int ret;
7242         struct extent_buffer *leaf;
7243         struct btrfs_root *root = BTRFS_I(inode)->root;
7244         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7245         struct btrfs_file_extent_item *fi;
7246         struct btrfs_key key;
7247         u64 disk_bytenr;
7248         u64 backref_offset;
7249         u64 extent_end;
7250         u64 num_bytes;
7251         int slot;
7252         int found_type;
7253         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
7254
7255         path = btrfs_alloc_path();
7256         if (!path)
7257                 return -ENOMEM;
7258
7259         ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode),
7260                                        offset, 0);
7261         if (ret < 0)
7262                 goto out;
7263
7264         slot = path->slots[0];
7265         if (ret == 1) {
7266                 if (slot == 0) {
7267                         /* can't find the item, must cow */
7268                         ret = 0;
7269                         goto out;
7270                 }
7271                 slot--;
7272         }
7273         ret = 0;
7274         leaf = path->nodes[0];
7275         btrfs_item_key_to_cpu(leaf, &key, slot);
7276         if (key.objectid != btrfs_ino(inode) ||
7277             key.type != BTRFS_EXTENT_DATA_KEY) {
7278                 /* not our file or wrong item type, must cow */
7279                 goto out;
7280         }
7281
7282         if (key.offset > offset) {
7283                 /* Wrong offset, must cow */
7284                 goto out;
7285         }
7286
7287         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
7288         found_type = btrfs_file_extent_type(leaf, fi);
7289         if (found_type != BTRFS_FILE_EXTENT_REG &&
7290             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
7291                 /* not a regular extent, must cow */
7292                 goto out;
7293         }
7294
7295         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
7296                 goto out;
7297
7298         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
7299         if (extent_end <= offset)
7300                 goto out;
7301
7302         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
7303         if (disk_bytenr == 0)
7304                 goto out;
7305
7306         if (btrfs_file_extent_compression(leaf, fi) ||
7307             btrfs_file_extent_encryption(leaf, fi) ||
7308             btrfs_file_extent_other_encoding(leaf, fi))
7309                 goto out;
7310
7311         backref_offset = btrfs_file_extent_offset(leaf, fi);
7312
7313         if (orig_start) {
7314                 *orig_start = key.offset - backref_offset;
7315                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
7316                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
7317         }
7318
7319         if (btrfs_extent_readonly(root, disk_bytenr))
7320                 goto out;
7321
7322         num_bytes = min(offset + *len, extent_end) - offset;
7323         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
7324                 u64 range_end;
7325
7326                 range_end = round_up(offset + num_bytes, root->sectorsize) - 1;
7327                 ret = test_range_bit(io_tree, offset, range_end,
7328                                      EXTENT_DELALLOC, 0, NULL);
7329                 if (ret) {
7330                         ret = -EAGAIN;
7331                         goto out;
7332                 }
7333         }
7334
7335         btrfs_release_path(path);
7336
7337         /*
7338          * look for other files referencing this extent, if we
7339          * find any we must cow
7340          */
7341         trans = btrfs_join_transaction(root);
7342         if (IS_ERR(trans)) {
7343                 ret = 0;
7344                 goto out;
7345         }
7346
7347         ret = btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
7348                                     key.offset - backref_offset, disk_bytenr);
7349         btrfs_end_transaction(trans, root);
7350         if (ret) {
7351                 ret = 0;
7352                 goto out;
7353         }
7354
7355         /*
7356          * adjust disk_bytenr and num_bytes to cover just the bytes
7357          * in this extent we are about to write.  If there
7358          * are any csums in that range we have to cow in order
7359          * to keep the csums correct
7360          */
7361         disk_bytenr += backref_offset;
7362         disk_bytenr += offset - key.offset;
7363         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
7364                                 goto out;
7365         /*
7366          * all of the above have passed, it is safe to overwrite this extent
7367          * without cow
7368          */
7369         *len = num_bytes;
7370         ret = 1;
7371 out:
7372         btrfs_free_path(path);
7373         return ret;
7374 }
7375
7376 bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end)
7377 {
7378         struct radix_tree_root *root = &inode->i_mapping->page_tree;
7379         int found = false;
7380         void **pagep = NULL;
7381         struct page *page = NULL;
7382         int start_idx;
7383         int end_idx;
7384
7385         start_idx = start >> PAGE_SHIFT;
7386
7387         /*
7388          * end is the last byte in the last page.  end == start is legal
7389          */
7390         end_idx = end >> PAGE_SHIFT;
7391
7392         rcu_read_lock();
7393
7394         /* Most of the code in this while loop is lifted from
7395          * find_get_page.  It's been modified to begin searching from a
7396          * page and return just the first page found in that range.  If the
7397          * found idx is less than or equal to the end idx then we know that
7398          * a page exists.  If no pages are found or if those pages are
7399          * outside of the range then we're fine (yay!) */
7400         while (page == NULL &&
7401                radix_tree_gang_lookup_slot(root, &pagep, NULL, start_idx, 1)) {
7402                 page = radix_tree_deref_slot(pagep);
7403                 if (unlikely(!page))
7404                         break;
7405
7406                 if (radix_tree_exception(page)) {
7407                         if (radix_tree_deref_retry(page)) {
7408                                 page = NULL;
7409                                 continue;
7410                         }
7411                         /*
7412                          * Otherwise, shmem/tmpfs must be storing a swap entry
7413                          * here as an exceptional entry: so return it without
7414                          * attempting to raise page count.
7415                          */
7416                         page = NULL;
7417                         break; /* TODO: Is this relevant for this use case? */
7418                 }
7419
7420                 if (!page_cache_get_speculative(page)) {
7421                         page = NULL;
7422                         continue;
7423                 }
7424
7425                 /*
7426                  * Has the page moved?
7427                  * This is part of the lockless pagecache protocol. See
7428                  * include/linux/pagemap.h for details.
7429                  */
7430                 if (unlikely(page != *pagep)) {
7431                         put_page(page);
7432                         page = NULL;
7433                 }
7434         }
7435
7436         if (page) {
7437                 if (page->index <= end_idx)
7438                         found = true;
7439                 put_page(page);
7440         }
7441
7442         rcu_read_unlock();
7443         return found;
7444 }
7445
7446 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
7447                               struct extent_state **cached_state, int writing)
7448 {
7449         struct btrfs_ordered_extent *ordered;
7450         int ret = 0;
7451
7452         while (1) {
7453                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7454                                  cached_state);
7455                 /*
7456                  * We're concerned with the entire range that we're going to be
7457                  * doing DIO to, so we need to make sure there's no ordered
7458                  * extents in this range.
7459                  */
7460                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
7461                                                      lockend - lockstart + 1);
7462
7463                 /*
7464                  * We need to make sure there are no buffered pages in this
7465                  * range either, we could have raced between the invalidate in
7466                  * generic_file_direct_write and locking the extent.  The
7467                  * invalidate needs to happen so that reads after a write do not
7468                  * get stale data.
7469                  */
7470                 if (!ordered &&
7471                     (!writing ||
7472                      !btrfs_page_exists_in_range(inode, lockstart, lockend)))
7473                         break;
7474
7475                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7476                                      cached_state, GFP_NOFS);
7477
7478                 if (ordered) {
7479                         /*
7480                          * If we are doing a DIO read and the ordered extent we
7481                          * found is for a buffered write, we can not wait for it
7482                          * to complete and retry, because if we do so we can
7483                          * deadlock with concurrent buffered writes on page
7484                          * locks. This happens only if our DIO read covers more
7485                          * than one extent map, if at this point has already
7486                          * created an ordered extent for a previous extent map
7487                          * and locked its range in the inode's io tree, and a
7488                          * concurrent write against that previous extent map's
7489                          * range and this range started (we unlock the ranges
7490                          * in the io tree only when the bios complete and
7491                          * buffered writes always lock pages before attempting
7492                          * to lock range in the io tree).
7493                          */
7494                         if (writing ||
7495                             test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags))
7496                                 btrfs_start_ordered_extent(inode, ordered, 1);
7497                         else
7498                                 ret = -ENOTBLK;
7499                         btrfs_put_ordered_extent(ordered);
7500                 } else {
7501                         /*
7502                          * We could trigger writeback for this range (and wait
7503                          * for it to complete) and then invalidate the pages for
7504                          * this range (through invalidate_inode_pages2_range()),
7505                          * but that can lead us to a deadlock with a concurrent
7506                          * call to readpages() (a buffered read or a defrag call
7507                          * triggered a readahead) on a page lock due to an
7508                          * ordered dio extent we created before but did not have
7509                          * yet a corresponding bio submitted (whence it can not
7510                          * complete), which makes readpages() wait for that
7511                          * ordered extent to complete while holding a lock on
7512                          * that page.
7513                          */
7514                         ret = -ENOTBLK;
7515                 }
7516
7517                 if (ret)
7518                         break;
7519
7520                 cond_resched();
7521         }
7522
7523         return ret;
7524 }
7525
7526 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
7527                                            u64 len, u64 orig_start,
7528                                            u64 block_start, u64 block_len,
7529                                            u64 orig_block_len, u64 ram_bytes,
7530                                            int type)
7531 {
7532         struct extent_map_tree *em_tree;
7533         struct extent_map *em;
7534         struct btrfs_root *root = BTRFS_I(inode)->root;
7535         int ret;
7536
7537         em_tree = &BTRFS_I(inode)->extent_tree;
7538         em = alloc_extent_map();
7539         if (!em)
7540                 return ERR_PTR(-ENOMEM);
7541
7542         em->start = start;
7543         em->orig_start = orig_start;
7544         em->mod_start = start;
7545         em->mod_len = len;
7546         em->len = len;
7547         em->block_len = block_len;
7548         em->block_start = block_start;
7549         em->bdev = root->fs_info->fs_devices->latest_bdev;
7550         em->orig_block_len = orig_block_len;
7551         em->ram_bytes = ram_bytes;
7552         em->generation = -1;
7553         set_bit(EXTENT_FLAG_PINNED, &em->flags);
7554         if (type == BTRFS_ORDERED_PREALLOC)
7555                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
7556
7557         do {
7558                 btrfs_drop_extent_cache(inode, em->start,
7559                                 em->start + em->len - 1, 0);
7560                 write_lock(&em_tree->lock);
7561                 ret = add_extent_mapping(em_tree, em, 1);
7562                 write_unlock(&em_tree->lock);
7563         } while (ret == -EEXIST);
7564
7565         if (ret) {
7566                 free_extent_map(em);
7567                 return ERR_PTR(ret);
7568         }
7569
7570         return em;
7571 }
7572
7573 static void adjust_dio_outstanding_extents(struct inode *inode,
7574                                            struct btrfs_dio_data *dio_data,
7575                                            const u64 len)
7576 {
7577         unsigned num_extents;
7578
7579         num_extents = (unsigned) div64_u64(len + BTRFS_MAX_EXTENT_SIZE - 1,
7580                                            BTRFS_MAX_EXTENT_SIZE);
7581         /*
7582          * If we have an outstanding_extents count still set then we're
7583          * within our reservation, otherwise we need to adjust our inode
7584          * counter appropriately.
7585          */
7586         if (dio_data->outstanding_extents) {
7587                 dio_data->outstanding_extents -= num_extents;
7588         } else {
7589                 spin_lock(&BTRFS_I(inode)->lock);
7590                 BTRFS_I(inode)->outstanding_extents += num_extents;
7591                 spin_unlock(&BTRFS_I(inode)->lock);
7592         }
7593 }
7594
7595 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
7596                                    struct buffer_head *bh_result, int create)
7597 {
7598         struct extent_map *em;
7599         struct btrfs_root *root = BTRFS_I(inode)->root;
7600         struct extent_state *cached_state = NULL;
7601         struct btrfs_dio_data *dio_data = NULL;
7602         u64 start = iblock << inode->i_blkbits;
7603         u64 lockstart, lockend;
7604         u64 len = bh_result->b_size;
7605         int unlock_bits = EXTENT_LOCKED;
7606         int ret = 0;
7607
7608         if (create)
7609                 unlock_bits |= EXTENT_DIRTY;
7610         else
7611                 len = min_t(u64, len, root->sectorsize);
7612
7613         lockstart = start;
7614         lockend = start + len - 1;
7615
7616         if (current->journal_info) {
7617                 /*
7618                  * Need to pull our outstanding extents and set journal_info to NULL so
7619                  * that anything that needs to check if there's a transaction doesn't get
7620                  * confused.
7621                  */
7622                 dio_data = current->journal_info;
7623                 current->journal_info = NULL;
7624         }
7625
7626         /*
7627          * If this errors out it's because we couldn't invalidate pagecache for
7628          * this range and we need to fallback to buffered.
7629          */
7630         if (lock_extent_direct(inode, lockstart, lockend, &cached_state,
7631                                create)) {
7632                 ret = -ENOTBLK;
7633                 goto err;
7634         }
7635
7636         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
7637         if (IS_ERR(em)) {
7638                 ret = PTR_ERR(em);
7639                 goto unlock_err;
7640         }
7641
7642         /*
7643          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
7644          * io.  INLINE is special, and we could probably kludge it in here, but
7645          * it's still buffered so for safety lets just fall back to the generic
7646          * buffered path.
7647          *
7648          * For COMPRESSED we _have_ to read the entire extent in so we can
7649          * decompress it, so there will be buffering required no matter what we
7650          * do, so go ahead and fallback to buffered.
7651          *
7652          * We return -ENOTBLK because that's what makes DIO go ahead and go back
7653          * to buffered IO.  Don't blame me, this is the price we pay for using
7654          * the generic code.
7655          */
7656         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
7657             em->block_start == EXTENT_MAP_INLINE) {
7658                 free_extent_map(em);
7659                 ret = -ENOTBLK;
7660                 goto unlock_err;
7661         }
7662
7663         /* Just a good old fashioned hole, return */
7664         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
7665                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
7666                 free_extent_map(em);
7667                 goto unlock_err;
7668         }
7669
7670         /*
7671          * We don't allocate a new extent in the following cases
7672          *
7673          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
7674          * existing extent.
7675          * 2) The extent is marked as PREALLOC.  We're good to go here and can
7676          * just use the extent.
7677          *
7678          */
7679         if (!create) {
7680                 len = min(len, em->len - (start - em->start));
7681                 lockstart = start + len;
7682                 goto unlock;
7683         }
7684
7685         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
7686             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
7687              em->block_start != EXTENT_MAP_HOLE)) {
7688                 int type;
7689                 u64 block_start, orig_start, orig_block_len, ram_bytes;
7690
7691                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7692                         type = BTRFS_ORDERED_PREALLOC;
7693                 else
7694                         type = BTRFS_ORDERED_NOCOW;
7695                 len = min(len, em->len - (start - em->start));
7696                 block_start = em->block_start + (start - em->start);
7697
7698                 if (can_nocow_extent(inode, start, &len, &orig_start,
7699                                      &orig_block_len, &ram_bytes) == 1 &&
7700                     btrfs_inc_nocow_writers(root->fs_info, block_start)) {
7701                         struct extent_map *em2;
7702
7703                         em2 = btrfs_create_dio_extent(inode, start, len,
7704                                                       orig_start, block_start,
7705                                                       len, orig_block_len,
7706                                                       ram_bytes, type);
7707                         btrfs_dec_nocow_writers(root->fs_info, block_start);
7708                         if (type == BTRFS_ORDERED_PREALLOC) {
7709                                 free_extent_map(em);
7710                                 em = em2;
7711                         }
7712                         if (em2 && IS_ERR(em2)) {
7713                                 ret = PTR_ERR(em2);
7714                                 goto unlock_err;
7715                         }
7716                         goto unlock;
7717                 }
7718         }
7719
7720         /*
7721          * this will cow the extent, reset the len in case we changed
7722          * it above
7723          */
7724         len = bh_result->b_size;
7725         free_extent_map(em);
7726         em = btrfs_new_extent_direct(inode, start, len);
7727         if (IS_ERR(em)) {
7728                 ret = PTR_ERR(em);
7729                 goto unlock_err;
7730         }
7731         len = min(len, em->len - (start - em->start));
7732 unlock:
7733         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7734                 inode->i_blkbits;
7735         bh_result->b_size = len;
7736         bh_result->b_bdev = em->bdev;
7737         set_buffer_mapped(bh_result);
7738         if (create) {
7739                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7740                         set_buffer_new(bh_result);
7741
7742                 /*
7743                  * Need to update the i_size under the extent lock so buffered
7744                  * readers will get the updated i_size when we unlock.
7745                  */
7746                 if (start + len > i_size_read(inode))
7747                         i_size_write(inode, start + len);
7748
7749                 adjust_dio_outstanding_extents(inode, dio_data, len);
7750                 btrfs_free_reserved_data_space(inode, start, len);
7751                 WARN_ON(dio_data->reserve < len);
7752                 dio_data->reserve -= len;
7753                 dio_data->unsubmitted_oe_range_end = start + len;
7754                 current->journal_info = dio_data;
7755         }
7756
7757         /*
7758          * In the case of write we need to clear and unlock the entire range,
7759          * in the case of read we need to unlock only the end area that we
7760          * aren't using if there is any left over space.
7761          */
7762         if (lockstart < lockend) {
7763                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
7764                                  lockend, unlock_bits, 1, 0,
7765                                  &cached_state, GFP_NOFS);
7766         } else {
7767                 free_extent_state(cached_state);
7768         }
7769
7770         free_extent_map(em);
7771
7772         return 0;
7773
7774 unlock_err:
7775         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7776                          unlock_bits, 1, 0, &cached_state, GFP_NOFS);
7777 err:
7778         if (dio_data)
7779                 current->journal_info = dio_data;
7780         /*
7781          * Compensate the delalloc release we do in btrfs_direct_IO() when we
7782          * write less data then expected, so that we don't underflow our inode's
7783          * outstanding extents counter.
7784          */
7785         if (create && dio_data)
7786                 adjust_dio_outstanding_extents(inode, dio_data, len);
7787
7788         return ret;
7789 }
7790
7791 static inline int submit_dio_repair_bio(struct inode *inode, struct bio *bio,
7792                                         int mirror_num)
7793 {
7794         struct btrfs_root *root = BTRFS_I(inode)->root;
7795         int ret;
7796
7797         BUG_ON(bio_op(bio) == REQ_OP_WRITE);
7798
7799         bio_get(bio);
7800
7801         ret = btrfs_bio_wq_end_io(root->fs_info, bio,
7802                                   BTRFS_WQ_ENDIO_DIO_REPAIR);
7803         if (ret)
7804                 goto err;
7805
7806         ret = btrfs_map_bio(root, bio, mirror_num, 0);
7807 err:
7808         bio_put(bio);
7809         return ret;
7810 }
7811
7812 static int btrfs_check_dio_repairable(struct inode *inode,
7813                                       struct bio *failed_bio,
7814                                       struct io_failure_record *failrec,
7815                                       int failed_mirror)
7816 {
7817         int num_copies;
7818
7819         num_copies = btrfs_num_copies(BTRFS_I(inode)->root->fs_info,
7820                                       failrec->logical, failrec->len);
7821         if (num_copies == 1) {
7822                 /*
7823                  * we only have a single copy of the data, so don't bother with
7824                  * all the retry and error correction code that follows. no
7825                  * matter what the error is, it is very likely to persist.
7826                  */
7827                 pr_debug("Check DIO Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d\n",
7828                          num_copies, failrec->this_mirror, failed_mirror);
7829                 return 0;
7830         }
7831
7832         failrec->failed_mirror = failed_mirror;
7833         failrec->this_mirror++;
7834         if (failrec->this_mirror == failed_mirror)
7835                 failrec->this_mirror++;
7836
7837         if (failrec->this_mirror > num_copies) {
7838                 pr_debug("Check DIO Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d\n",
7839                          num_copies, failrec->this_mirror, failed_mirror);
7840                 return 0;
7841         }
7842
7843         return 1;
7844 }
7845
7846 static int dio_read_error(struct inode *inode, struct bio *failed_bio,
7847                         struct page *page, unsigned int pgoff,
7848                         u64 start, u64 end, int failed_mirror,
7849                         bio_end_io_t *repair_endio, void *repair_arg)
7850 {
7851         struct io_failure_record *failrec;
7852         struct bio *bio;
7853         int isector;
7854         int read_mode;
7855         int ret;
7856
7857         BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
7858
7859         ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
7860         if (ret)
7861                 return ret;
7862
7863         ret = btrfs_check_dio_repairable(inode, failed_bio, failrec,
7864                                          failed_mirror);
7865         if (!ret) {
7866                 free_io_failure(inode, failrec);
7867                 return -EIO;
7868         }
7869
7870         if ((failed_bio->bi_vcnt > 1)
7871                 || (failed_bio->bi_io_vec->bv_len
7872                         > BTRFS_I(inode)->root->sectorsize))
7873                 read_mode = READ_SYNC | REQ_FAILFAST_DEV;
7874         else
7875                 read_mode = READ_SYNC;
7876
7877         isector = start - btrfs_io_bio(failed_bio)->logical;
7878         isector >>= inode->i_sb->s_blocksize_bits;
7879         bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
7880                                 pgoff, isector, repair_endio, repair_arg);
7881         if (!bio) {
7882                 free_io_failure(inode, failrec);
7883                 return -EIO;
7884         }
7885         bio_set_op_attrs(bio, REQ_OP_READ, read_mode);
7886
7887         btrfs_debug(BTRFS_I(inode)->root->fs_info,
7888                     "Repair DIO Read Error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d\n",
7889                     read_mode, failrec->this_mirror, failrec->in_validation);
7890
7891         ret = submit_dio_repair_bio(inode, bio, failrec->this_mirror);
7892         if (ret) {
7893                 free_io_failure(inode, failrec);
7894                 bio_put(bio);
7895         }
7896
7897         return ret;
7898 }
7899
7900 struct btrfs_retry_complete {
7901         struct completion done;
7902         struct inode *inode;
7903         u64 start;
7904         int uptodate;
7905 };
7906
7907 static void btrfs_retry_endio_nocsum(struct bio *bio)
7908 {
7909         struct btrfs_retry_complete *done = bio->bi_private;
7910         struct inode *inode;
7911         struct bio_vec *bvec;
7912         int i;
7913
7914         if (bio->bi_error)
7915                 goto end;
7916
7917         ASSERT(bio->bi_vcnt == 1);
7918         inode = bio->bi_io_vec->bv_page->mapping->host;
7919         ASSERT(bio->bi_io_vec->bv_len == BTRFS_I(inode)->root->sectorsize);
7920
7921         done->uptodate = 1;
7922         bio_for_each_segment_all(bvec, bio, i)
7923                 clean_io_failure(done->inode, done->start, bvec->bv_page, 0);
7924 end:
7925         complete(&done->done);
7926         bio_put(bio);
7927 }
7928
7929 static int __btrfs_correct_data_nocsum(struct inode *inode,
7930                                        struct btrfs_io_bio *io_bio)
7931 {
7932         struct btrfs_fs_info *fs_info;
7933         struct bio_vec *bvec;
7934         struct btrfs_retry_complete done;
7935         u64 start;
7936         unsigned int pgoff;
7937         u32 sectorsize;
7938         int nr_sectors;
7939         int i;
7940         int ret;
7941
7942         fs_info = BTRFS_I(inode)->root->fs_info;
7943         sectorsize = BTRFS_I(inode)->root->sectorsize;
7944
7945         start = io_bio->logical;
7946         done.inode = inode;
7947
7948         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
7949                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
7950                 pgoff = bvec->bv_offset;
7951
7952 next_block_or_try_again:
7953                 done.uptodate = 0;
7954                 done.start = start;
7955                 init_completion(&done.done);
7956
7957                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page,
7958                                 pgoff, start, start + sectorsize - 1,
7959                                 io_bio->mirror_num,
7960                                 btrfs_retry_endio_nocsum, &done);
7961                 if (ret)
7962                         return ret;
7963
7964                 wait_for_completion(&done.done);
7965
7966                 if (!done.uptodate) {
7967                         /* We might have another mirror, so try again */
7968                         goto next_block_or_try_again;
7969                 }
7970
7971                 start += sectorsize;
7972
7973                 if (nr_sectors--) {
7974                         pgoff += sectorsize;
7975                         goto next_block_or_try_again;
7976                 }
7977         }
7978
7979         return 0;
7980 }
7981
7982 static void btrfs_retry_endio(struct bio *bio)
7983 {
7984         struct btrfs_retry_complete *done = bio->bi_private;
7985         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7986         struct inode *inode;
7987         struct bio_vec *bvec;
7988         u64 start;
7989         int uptodate;
7990         int ret;
7991         int i;
7992
7993         if (bio->bi_error)
7994                 goto end;
7995
7996         uptodate = 1;
7997
7998         start = done->start;
7999
8000         ASSERT(bio->bi_vcnt == 1);
8001         inode = bio->bi_io_vec->bv_page->mapping->host;
8002         ASSERT(bio->bi_io_vec->bv_len == BTRFS_I(inode)->root->sectorsize);
8003
8004         bio_for_each_segment_all(bvec, bio, i) {
8005                 ret = __readpage_endio_check(done->inode, io_bio, i,
8006                                         bvec->bv_page, bvec->bv_offset,
8007                                         done->start, bvec->bv_len);
8008                 if (!ret)
8009                         clean_io_failure(done->inode, done->start,
8010                                         bvec->bv_page, bvec->bv_offset);
8011                 else
8012                         uptodate = 0;
8013         }
8014
8015         done->uptodate = uptodate;
8016 end:
8017         complete(&done->done);
8018         bio_put(bio);
8019 }
8020
8021 static int __btrfs_subio_endio_read(struct inode *inode,
8022                                     struct btrfs_io_bio *io_bio, int err)
8023 {
8024         struct btrfs_fs_info *fs_info;
8025         struct bio_vec *bvec;
8026         struct btrfs_retry_complete done;
8027         u64 start;
8028         u64 offset = 0;
8029         u32 sectorsize;
8030         int nr_sectors;
8031         unsigned int pgoff;
8032         int csum_pos;
8033         int i;
8034         int ret;
8035
8036         fs_info = BTRFS_I(inode)->root->fs_info;
8037         sectorsize = BTRFS_I(inode)->root->sectorsize;
8038
8039         err = 0;
8040         start = io_bio->logical;
8041         done.inode = inode;
8042
8043         bio_for_each_segment_all(bvec, &io_bio->bio, i) {
8044                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
8045
8046                 pgoff = bvec->bv_offset;
8047 next_block:
8048                 csum_pos = BTRFS_BYTES_TO_BLKS(fs_info, offset);
8049                 ret = __readpage_endio_check(inode, io_bio, csum_pos,
8050                                         bvec->bv_page, pgoff, start,
8051                                         sectorsize);
8052                 if (likely(!ret))
8053                         goto next;
8054 try_again:
8055                 done.uptodate = 0;
8056                 done.start = start;
8057                 init_completion(&done.done);
8058
8059                 ret = dio_read_error(inode, &io_bio->bio, bvec->bv_page,
8060                                 pgoff, start, start + sectorsize - 1,
8061                                 io_bio->mirror_num,
8062                                 btrfs_retry_endio, &done);
8063                 if (ret) {
8064                         err = ret;
8065                         goto next;
8066                 }
8067
8068                 wait_for_completion(&done.done);
8069
8070                 if (!done.uptodate) {
8071                         /* We might have another mirror, so try again */
8072                         goto try_again;
8073                 }
8074 next:
8075                 offset += sectorsize;
8076                 start += sectorsize;
8077
8078                 ASSERT(nr_sectors);
8079
8080                 if (--nr_sectors) {
8081                         pgoff += sectorsize;
8082                         goto next_block;
8083                 }
8084         }
8085
8086         return err;
8087 }
8088
8089 static int btrfs_subio_endio_read(struct inode *inode,
8090                                   struct btrfs_io_bio *io_bio, int err)
8091 {
8092         bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
8093
8094         if (skip_csum) {
8095                 if (unlikely(err))
8096                         return __btrfs_correct_data_nocsum(inode, io_bio);
8097                 else
8098                         return 0;
8099         } else {
8100                 return __btrfs_subio_endio_read(inode, io_bio, err);
8101         }
8102 }
8103
8104 static void btrfs_endio_direct_read(struct bio *bio)
8105 {
8106         struct btrfs_dio_private *dip = bio->bi_private;
8107         struct inode *inode = dip->inode;
8108         struct bio *dio_bio;
8109         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8110         int err = bio->bi_error;
8111
8112         if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED)
8113                 err = btrfs_subio_endio_read(inode, io_bio, err);
8114
8115         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
8116                       dip->logical_offset + dip->bytes - 1);
8117         dio_bio = dip->dio_bio;
8118
8119         kfree(dip);
8120
8121         dio_bio->bi_error = bio->bi_error;
8122         dio_end_io(dio_bio, bio->bi_error);
8123
8124         if (io_bio->end_io)
8125                 io_bio->end_io(io_bio, err);
8126         bio_put(bio);
8127 }
8128
8129 static void btrfs_endio_direct_write_update_ordered(struct inode *inode,
8130                                                     const u64 offset,
8131                                                     const u64 bytes,
8132                                                     const int uptodate)
8133 {
8134         struct btrfs_root *root = BTRFS_I(inode)->root;
8135         struct btrfs_ordered_extent *ordered = NULL;
8136         u64 ordered_offset = offset;
8137         u64 ordered_bytes = bytes;
8138         int ret;
8139
8140 again:
8141         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
8142                                                    &ordered_offset,
8143                                                    ordered_bytes,
8144                                                    uptodate);
8145         if (!ret)
8146                 goto out_test;
8147
8148         btrfs_init_work(&ordered->work, btrfs_endio_write_helper,
8149                         finish_ordered_fn, NULL, NULL);
8150         btrfs_queue_work(root->fs_info->endio_write_workers,
8151                          &ordered->work);
8152 out_test:
8153         /*
8154          * our bio might span multiple ordered extents.  If we haven't
8155          * completed the accounting for the whole dio, go back and try again
8156          */
8157         if (ordered_offset < offset + bytes) {
8158                 ordered_bytes = offset + bytes - ordered_offset;
8159                 ordered = NULL;
8160                 goto again;
8161         }
8162 }
8163
8164 static void btrfs_endio_direct_write(struct bio *bio)
8165 {
8166         struct btrfs_dio_private *dip = bio->bi_private;
8167         struct bio *dio_bio = dip->dio_bio;
8168
8169         btrfs_endio_direct_write_update_ordered(dip->inode,
8170                                                 dip->logical_offset,
8171                                                 dip->bytes,
8172                                                 !bio->bi_error);
8173
8174         kfree(dip);
8175
8176         dio_bio->bi_error = bio->bi_error;
8177         dio_end_io(dio_bio, bio->bi_error);
8178         bio_put(bio);
8179 }
8180
8181 static int __btrfs_submit_bio_start_direct_io(struct inode *inode,
8182                                     struct bio *bio, int mirror_num,
8183                                     unsigned long bio_flags, u64 offset)
8184 {
8185         int ret;
8186         struct btrfs_root *root = BTRFS_I(inode)->root;
8187         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
8188         BUG_ON(ret); /* -ENOMEM */
8189         return 0;
8190 }
8191
8192 static void btrfs_end_dio_bio(struct bio *bio)
8193 {
8194         struct btrfs_dio_private *dip = bio->bi_private;
8195         int err = bio->bi_error;
8196
8197         if (err)
8198                 btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
8199                            "direct IO failed ino %llu rw %d,%u sector %#Lx len %u err no %d",
8200                            btrfs_ino(dip->inode), bio_op(bio), bio->bi_rw,
8201                            (unsigned long long)bio->bi_iter.bi_sector,
8202                            bio->bi_iter.bi_size, err);
8203
8204         if (dip->subio_endio)
8205                 err = dip->subio_endio(dip->inode, btrfs_io_bio(bio), err);
8206
8207         if (err) {
8208                 dip->errors = 1;
8209
8210                 /*
8211                  * before atomic variable goto zero, we must make sure
8212                  * dip->errors is perceived to be set.
8213                  */
8214                 smp_mb__before_atomic();
8215         }
8216
8217         /* if there are more bios still pending for this dio, just exit */
8218         if (!atomic_dec_and_test(&dip->pending_bios))
8219                 goto out;
8220
8221         if (dip->errors) {
8222                 bio_io_error(dip->orig_bio);
8223         } else {
8224                 dip->dio_bio->bi_error = 0;
8225                 bio_endio(dip->orig_bio);
8226         }
8227 out:
8228         bio_put(bio);
8229 }
8230
8231 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
8232                                        u64 first_sector, gfp_t gfp_flags)
8233 {
8234         struct bio *bio;
8235         bio = btrfs_bio_alloc(bdev, first_sector, BIO_MAX_PAGES, gfp_flags);
8236         if (bio)
8237                 bio_associate_current(bio);
8238         return bio;
8239 }
8240
8241 static inline int btrfs_lookup_and_bind_dio_csum(struct btrfs_root *root,
8242                                                  struct inode *inode,
8243                                                  struct btrfs_dio_private *dip,
8244                                                  struct bio *bio,
8245                                                  u64 file_offset)
8246 {
8247         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
8248         struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
8249         int ret;
8250
8251         /*
8252          * We load all the csum data we need when we submit
8253          * the first bio to reduce the csum tree search and
8254          * contention.
8255          */
8256         if (dip->logical_offset == file_offset) {
8257                 ret = btrfs_lookup_bio_sums_dio(root, inode, dip->orig_bio,
8258                                                 file_offset);
8259                 if (ret)
8260                         return ret;
8261         }
8262
8263         if (bio == dip->orig_bio)
8264                 return 0;
8265
8266         file_offset -= dip->logical_offset;
8267         file_offset >>= inode->i_sb->s_blocksize_bits;
8268         io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
8269
8270         return 0;
8271 }
8272
8273 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
8274                                          u64 file_offset, int skip_sum,
8275                                          int async_submit)
8276 {
8277         struct btrfs_dio_private *dip = bio->bi_private;
8278         bool write = bio_op(bio) == REQ_OP_WRITE;
8279         struct btrfs_root *root = BTRFS_I(inode)->root;
8280         int ret;
8281
8282         if (async_submit)
8283                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
8284
8285         bio_get(bio);
8286
8287         if (!write) {
8288                 ret = btrfs_bio_wq_end_io(root->fs_info, bio,
8289                                 BTRFS_WQ_ENDIO_DATA);
8290                 if (ret)
8291                         goto err;
8292         }
8293
8294         if (skip_sum)
8295                 goto map;
8296
8297         if (write && async_submit) {
8298                 ret = btrfs_wq_submit_bio(root->fs_info,
8299                                    inode, bio, 0, 0, file_offset,
8300                                    __btrfs_submit_bio_start_direct_io,
8301                                    __btrfs_submit_bio_done);
8302                 goto err;
8303         } else if (write) {
8304                 /*
8305                  * If we aren't doing async submit, calculate the csum of the
8306                  * bio now.
8307                  */
8308                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
8309                 if (ret)
8310                         goto err;
8311         } else {
8312                 ret = btrfs_lookup_and_bind_dio_csum(root, inode, dip, bio,
8313                                                      file_offset);
8314                 if (ret)
8315                         goto err;
8316         }
8317 map:
8318         ret = btrfs_map_bio(root, bio, 0, async_submit);
8319 err:
8320         bio_put(bio);
8321         return ret;
8322 }
8323
8324 static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip,
8325                                     int skip_sum)
8326 {
8327         struct inode *inode = dip->inode;
8328         struct btrfs_root *root = BTRFS_I(inode)->root;
8329         struct bio *bio;
8330         struct bio *orig_bio = dip->orig_bio;
8331         struct bio_vec *bvec = orig_bio->bi_io_vec;
8332         u64 start_sector = orig_bio->bi_iter.bi_sector;
8333         u64 file_offset = dip->logical_offset;
8334         u64 submit_len = 0;
8335         u64 map_length;
8336         u32 blocksize = root->sectorsize;
8337         int async_submit = 0;
8338         int nr_sectors;
8339         int ret;
8340         int i;
8341
8342         map_length = orig_bio->bi_iter.bi_size;
8343         ret = btrfs_map_block(root->fs_info, bio_op(orig_bio),
8344                               start_sector << 9, &map_length, NULL, 0);
8345         if (ret)
8346                 return -EIO;
8347
8348         if (map_length >= orig_bio->bi_iter.bi_size) {
8349                 bio = orig_bio;
8350                 dip->flags |= BTRFS_DIO_ORIG_BIO_SUBMITTED;
8351                 goto submit;
8352         }
8353
8354         /* async crcs make it difficult to collect full stripe writes. */
8355         if (btrfs_get_alloc_profile(root, 1) & BTRFS_BLOCK_GROUP_RAID56_MASK)
8356                 async_submit = 0;
8357         else
8358                 async_submit = 1;
8359
8360         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
8361         if (!bio)
8362                 return -ENOMEM;
8363
8364         bio_set_op_attrs(bio, bio_op(orig_bio), orig_bio->bi_rw);
8365         bio->bi_private = dip;
8366         bio->bi_end_io = btrfs_end_dio_bio;
8367         btrfs_io_bio(bio)->logical = file_offset;
8368         atomic_inc(&dip->pending_bios);
8369
8370         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
8371                 nr_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info, bvec->bv_len);
8372                 i = 0;
8373 next_block:
8374                 if (unlikely(map_length < submit_len + blocksize ||
8375                     bio_add_page(bio, bvec->bv_page, blocksize,
8376                             bvec->bv_offset + (i * blocksize)) < blocksize)) {
8377                         /*
8378                          * inc the count before we submit the bio so
8379                          * we know the end IO handler won't happen before
8380                          * we inc the count. Otherwise, the dip might get freed
8381                          * before we're done setting it up
8382                          */
8383                         atomic_inc(&dip->pending_bios);
8384                         ret = __btrfs_submit_dio_bio(bio, inode,
8385                                                      file_offset, skip_sum,
8386                                                      async_submit);
8387                         if (ret) {
8388                                 bio_put(bio);
8389                                 atomic_dec(&dip->pending_bios);
8390                                 goto out_err;
8391                         }
8392
8393                         start_sector += submit_len >> 9;
8394                         file_offset += submit_len;
8395
8396                         submit_len = 0;
8397
8398                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
8399                                                   start_sector, GFP_NOFS);
8400                         if (!bio)
8401                                 goto out_err;
8402                         bio_set_op_attrs(bio, bio_op(orig_bio), orig_bio->bi_rw);
8403                         bio->bi_private = dip;
8404                         bio->bi_end_io = btrfs_end_dio_bio;
8405                         btrfs_io_bio(bio)->logical = file_offset;
8406
8407                         map_length = orig_bio->bi_iter.bi_size;
8408                         ret = btrfs_map_block(root->fs_info, bio_op(orig_bio),
8409                                               start_sector << 9,
8410                                               &map_length, NULL, 0);
8411                         if (ret) {
8412                                 bio_put(bio);
8413                                 goto out_err;
8414                         }
8415
8416                         goto next_block;
8417                 } else {
8418                         submit_len += blocksize;
8419                         if (--nr_sectors) {
8420                                 i++;
8421                                 goto next_block;
8422                         }
8423                         bvec++;
8424                 }
8425         }
8426
8427 submit:
8428         ret = __btrfs_submit_dio_bio(bio, inode, file_offset, skip_sum,
8429                                      async_submit);
8430         if (!ret)
8431                 return 0;
8432
8433         bio_put(bio);
8434 out_err:
8435         dip->errors = 1;
8436         /*
8437          * before atomic variable goto zero, we must
8438          * make sure dip->errors is perceived to be set.
8439          */
8440         smp_mb__before_atomic();
8441         if (atomic_dec_and_test(&dip->pending_bios))
8442                 bio_io_error(dip->orig_bio);
8443
8444         /* bio_end_io() will handle error, so we needn't return it */
8445         return 0;
8446 }
8447
8448 static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
8449                                 loff_t file_offset)
8450 {
8451         struct btrfs_dio_private *dip = NULL;
8452         struct bio *io_bio = NULL;
8453         struct btrfs_io_bio *btrfs_bio;
8454         int skip_sum;
8455         bool write = (bio_op(dio_bio) == REQ_OP_WRITE);
8456         int ret = 0;
8457
8458         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
8459
8460         io_bio = btrfs_bio_clone(dio_bio, GFP_NOFS);
8461         if (!io_bio) {
8462                 ret = -ENOMEM;
8463                 goto free_ordered;
8464         }
8465
8466         dip = kzalloc(sizeof(*dip), GFP_NOFS);
8467         if (!dip) {
8468                 ret = -ENOMEM;
8469                 goto free_ordered;
8470         }
8471
8472         dip->private = dio_bio->bi_private;
8473         dip->inode = inode;
8474         dip->logical_offset = file_offset;
8475         dip->bytes = dio_bio->bi_iter.bi_size;
8476         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
8477         io_bio->bi_private = dip;
8478         dip->orig_bio = io_bio;
8479         dip->dio_bio = dio_bio;
8480         atomic_set(&dip->pending_bios, 0);
8481         btrfs_bio = btrfs_io_bio(io_bio);
8482         btrfs_bio->logical = file_offset;
8483
8484         if (write) {
8485                 io_bio->bi_end_io = btrfs_endio_direct_write;
8486         } else {
8487                 io_bio->bi_end_io = btrfs_endio_direct_read;
8488                 dip->subio_endio = btrfs_subio_endio_read;
8489         }
8490
8491         /*
8492          * Reset the range for unsubmitted ordered extents (to a 0 length range)
8493          * even if we fail to submit a bio, because in such case we do the
8494          * corresponding error handling below and it must not be done a second
8495          * time by btrfs_direct_IO().
8496          */
8497         if (write) {
8498                 struct btrfs_dio_data *dio_data = current->journal_info;
8499
8500                 dio_data->unsubmitted_oe_range_end = dip->logical_offset +
8501                         dip->bytes;
8502                 dio_data->unsubmitted_oe_range_start =
8503                         dio_data->unsubmitted_oe_range_end;
8504         }
8505
8506         ret = btrfs_submit_direct_hook(dip, skip_sum);
8507         if (!ret)
8508                 return;
8509
8510         if (btrfs_bio->end_io)
8511                 btrfs_bio->end_io(btrfs_bio, ret);
8512
8513 free_ordered:
8514         /*
8515          * If we arrived here it means either we failed to submit the dip
8516          * or we either failed to clone the dio_bio or failed to allocate the
8517          * dip. If we cloned the dio_bio and allocated the dip, we can just
8518          * call bio_endio against our io_bio so that we get proper resource
8519          * cleanup if we fail to submit the dip, otherwise, we must do the
8520          * same as btrfs_endio_direct_[write|read] because we can't call these
8521          * callbacks - they require an allocated dip and a clone of dio_bio.
8522          */
8523         if (io_bio && dip) {
8524                 io_bio->bi_error = -EIO;
8525                 bio_endio(io_bio);
8526                 /*
8527                  * The end io callbacks free our dip, do the final put on io_bio
8528                  * and all the cleanup and final put for dio_bio (through
8529                  * dio_end_io()).
8530                  */
8531                 dip = NULL;
8532                 io_bio = NULL;
8533         } else {
8534                 if (write)
8535                         btrfs_endio_direct_write_update_ordered(inode,
8536                                                 file_offset,
8537                                                 dio_bio->bi_iter.bi_size,
8538                                                 0);
8539                 else
8540                         unlock_extent(&BTRFS_I(inode)->io_tree, file_offset,
8541                               file_offset + dio_bio->bi_iter.bi_size - 1);
8542
8543                 dio_bio->bi_error = -EIO;
8544                 /*
8545                  * Releases and cleans up our dio_bio, no need to bio_put()
8546                  * nor bio_endio()/bio_io_error() against dio_bio.
8547                  */
8548                 dio_end_io(dio_bio, ret);
8549         }
8550         if (io_bio)
8551                 bio_put(io_bio);
8552         kfree(dip);
8553 }
8554
8555 static ssize_t check_direct_IO(struct btrfs_root *root, struct kiocb *iocb,
8556                         const struct iov_iter *iter, loff_t offset)
8557 {
8558         int seg;
8559         int i;
8560         unsigned blocksize_mask = root->sectorsize - 1;
8561         ssize_t retval = -EINVAL;
8562
8563         if (offset & blocksize_mask)
8564                 goto out;
8565
8566         if (iov_iter_alignment(iter) & blocksize_mask)
8567                 goto out;
8568
8569         /* If this is a write we don't need to check anymore */
8570         if (iov_iter_rw(iter) == WRITE)
8571                 return 0;
8572         /*
8573          * Check to make sure we don't have duplicate iov_base's in this
8574          * iovec, if so return EINVAL, otherwise we'll get csum errors
8575          * when reading back.
8576          */
8577         for (seg = 0; seg < iter->nr_segs; seg++) {
8578                 for (i = seg + 1; i < iter->nr_segs; i++) {
8579                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
8580                                 goto out;
8581                 }
8582         }
8583         retval = 0;
8584 out:
8585         return retval;
8586 }
8587
8588 static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
8589 {
8590         struct file *file = iocb->ki_filp;
8591         struct inode *inode = file->f_mapping->host;
8592         struct btrfs_root *root = BTRFS_I(inode)->root;
8593         struct btrfs_dio_data dio_data = { 0 };
8594         loff_t offset = iocb->ki_pos;
8595         size_t count = 0;
8596         int flags = 0;
8597         bool wakeup = true;
8598         bool relock = false;
8599         ssize_t ret;
8600
8601         if (check_direct_IO(BTRFS_I(inode)->root, iocb, iter, offset))
8602                 return 0;
8603
8604         inode_dio_begin(inode);
8605         smp_mb__after_atomic();
8606
8607         /*
8608          * The generic stuff only does filemap_write_and_wait_range, which
8609          * isn't enough if we've written compressed pages to this area, so
8610          * we need to flush the dirty pages again to make absolutely sure
8611          * that any outstanding dirty pages are on disk.
8612          */
8613         count = iov_iter_count(iter);
8614         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8615                      &BTRFS_I(inode)->runtime_flags))
8616                 filemap_fdatawrite_range(inode->i_mapping, offset,
8617                                          offset + count - 1);
8618
8619         if (iov_iter_rw(iter) == WRITE) {
8620                 /*
8621                  * If the write DIO is beyond the EOF, we need update
8622                  * the isize, but it is protected by i_mutex. So we can
8623                  * not unlock the i_mutex at this case.
8624                  */
8625                 if (offset + count <= inode->i_size) {
8626                         inode_unlock(inode);
8627                         relock = true;
8628                 }
8629                 ret = btrfs_delalloc_reserve_space(inode, offset, count);
8630                 if (ret)
8631                         goto out;
8632                 dio_data.outstanding_extents = div64_u64(count +
8633                                                 BTRFS_MAX_EXTENT_SIZE - 1,
8634                                                 BTRFS_MAX_EXTENT_SIZE);
8635
8636                 /*
8637                  * We need to know how many extents we reserved so that we can
8638                  * do the accounting properly if we go over the number we
8639                  * originally calculated.  Abuse current->journal_info for this.
8640                  */
8641                 dio_data.reserve = round_up(count, root->sectorsize);
8642                 dio_data.unsubmitted_oe_range_start = (u64)offset;
8643                 dio_data.unsubmitted_oe_range_end = (u64)offset;
8644                 current->journal_info = &dio_data;
8645         } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
8646                                      &BTRFS_I(inode)->runtime_flags)) {
8647                 inode_dio_end(inode);
8648                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
8649                 wakeup = false;
8650         }
8651
8652         ret = __blockdev_direct_IO(iocb, inode,
8653                                    BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
8654                                    iter, btrfs_get_blocks_direct, NULL,
8655                                    btrfs_submit_direct, flags);
8656         if (iov_iter_rw(iter) == WRITE) {
8657                 current->journal_info = NULL;
8658                 if (ret < 0 && ret != -EIOCBQUEUED) {
8659                         if (dio_data.reserve)
8660                                 btrfs_delalloc_release_space(inode, offset,
8661                                                              dio_data.reserve);
8662                         /*
8663                          * On error we might have left some ordered extents
8664                          * without submitting corresponding bios for them, so
8665                          * cleanup them up to avoid other tasks getting them
8666                          * and waiting for them to complete forever.
8667                          */
8668                         if (dio_data.unsubmitted_oe_range_start <
8669                             dio_data.unsubmitted_oe_range_end)
8670                                 btrfs_endio_direct_write_update_ordered(inode,
8671                                         dio_data.unsubmitted_oe_range_start,
8672                                         dio_data.unsubmitted_oe_range_end -
8673                                         dio_data.unsubmitted_oe_range_start,
8674                                         0);
8675                 } else if (ret >= 0 && (size_t)ret < count)
8676                         btrfs_delalloc_release_space(inode, offset,
8677                                                      count - (size_t)ret);
8678         }
8679 out:
8680         if (wakeup)
8681                 inode_dio_end(inode);
8682         if (relock)
8683                 inode_lock(inode);
8684
8685         return ret;
8686 }
8687
8688 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
8689
8690 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
8691                 __u64 start, __u64 len)
8692 {
8693         int     ret;
8694
8695         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
8696         if (ret)
8697                 return ret;
8698
8699         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
8700 }
8701
8702 int btrfs_readpage(struct file *file, struct page *page)
8703 {
8704         struct extent_io_tree *tree;
8705         tree = &BTRFS_I(page->mapping->host)->io_tree;
8706         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
8707 }
8708
8709 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
8710 {
8711         struct extent_io_tree *tree;
8712         struct inode *inode = page->mapping->host;
8713         int ret;
8714
8715         if (current->flags & PF_MEMALLOC) {
8716                 redirty_page_for_writepage(wbc, page);
8717                 unlock_page(page);
8718                 return 0;
8719         }
8720
8721         /*
8722          * If we are under memory pressure we will call this directly from the
8723          * VM, we need to make sure we have the inode referenced for the ordered
8724          * extent.  If not just return like we didn't do anything.
8725          */
8726         if (!igrab(inode)) {
8727                 redirty_page_for_writepage(wbc, page);
8728                 return AOP_WRITEPAGE_ACTIVATE;
8729         }
8730         tree = &BTRFS_I(page->mapping->host)->io_tree;
8731         ret = extent_write_full_page(tree, page, btrfs_get_extent, wbc);
8732         btrfs_add_delayed_iput(inode);
8733         return ret;
8734 }
8735
8736 static int btrfs_writepages(struct address_space *mapping,
8737                             struct writeback_control *wbc)
8738 {
8739         struct extent_io_tree *tree;
8740
8741         tree = &BTRFS_I(mapping->host)->io_tree;
8742         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
8743 }
8744
8745 static int
8746 btrfs_readpages(struct file *file, struct address_space *mapping,
8747                 struct list_head *pages, unsigned nr_pages)
8748 {
8749         struct extent_io_tree *tree;
8750         tree = &BTRFS_I(mapping->host)->io_tree;
8751         return extent_readpages(tree, mapping, pages, nr_pages,
8752                                 btrfs_get_extent);
8753 }
8754 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8755 {
8756         struct extent_io_tree *tree;
8757         struct extent_map_tree *map;
8758         int ret;
8759
8760         tree = &BTRFS_I(page->mapping->host)->io_tree;
8761         map = &BTRFS_I(page->mapping->host)->extent_tree;
8762         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
8763         if (ret == 1) {
8764                 ClearPagePrivate(page);
8765                 set_page_private(page, 0);
8766                 put_page(page);
8767         }
8768         return ret;
8769 }
8770
8771 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8772 {
8773         if (PageWriteback(page) || PageDirty(page))
8774                 return 0;
8775         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
8776 }
8777
8778 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
8779                                  unsigned int length)
8780 {
8781         struct inode *inode = page->mapping->host;
8782         struct extent_io_tree *tree;
8783         struct btrfs_ordered_extent *ordered;
8784         struct extent_state *cached_state = NULL;
8785         u64 page_start = page_offset(page);
8786         u64 page_end = page_start + PAGE_SIZE - 1;
8787         u64 start;
8788         u64 end;
8789         int inode_evicting = inode->i_state & I_FREEING;
8790
8791         /*
8792          * we have the page locked, so new writeback can't start,
8793          * and the dirty bit won't be cleared while we are here.
8794          *
8795          * Wait for IO on this page so that we can safely clear
8796          * the PagePrivate2 bit and do ordered accounting
8797          */
8798         wait_on_page_writeback(page);
8799
8800         tree = &BTRFS_I(inode)->io_tree;
8801         if (offset) {
8802                 btrfs_releasepage(page, GFP_NOFS);
8803                 return;
8804         }
8805
8806         if (!inode_evicting)
8807                 lock_extent_bits(tree, page_start, page_end, &cached_state);
8808 again:
8809         start = page_start;
8810         ordered = btrfs_lookup_ordered_range(inode, start,
8811                                         page_end - start + 1);
8812         if (ordered) {
8813                 end = min(page_end, ordered->file_offset + ordered->len - 1);
8814                 /*
8815                  * IO on this page will never be started, so we need
8816                  * to account for any ordered extents now
8817                  */
8818                 if (!inode_evicting)
8819                         clear_extent_bit(tree, start, end,
8820                                          EXTENT_DIRTY | EXTENT_DELALLOC |
8821                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
8822                                          EXTENT_DEFRAG, 1, 0, &cached_state,
8823                                          GFP_NOFS);
8824                 /*
8825                  * whoever cleared the private bit is responsible
8826                  * for the finish_ordered_io
8827                  */
8828                 if (TestClearPagePrivate2(page)) {
8829                         struct btrfs_ordered_inode_tree *tree;
8830                         u64 new_len;
8831
8832                         tree = &BTRFS_I(inode)->ordered_tree;
8833
8834                         spin_lock_irq(&tree->lock);
8835                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
8836                         new_len = start - ordered->file_offset;
8837                         if (new_len < ordered->truncated_len)
8838                                 ordered->truncated_len = new_len;
8839                         spin_unlock_irq(&tree->lock);
8840
8841                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
8842                                                            start,
8843                                                            end - start + 1, 1))
8844                                 btrfs_finish_ordered_io(ordered);
8845                 }
8846                 btrfs_put_ordered_extent(ordered);
8847                 if (!inode_evicting) {
8848                         cached_state = NULL;
8849                         lock_extent_bits(tree, start, end,
8850                                          &cached_state);
8851                 }
8852
8853                 start = end + 1;
8854                 if (start < page_end)
8855                         goto again;
8856         }
8857
8858         /*
8859          * Qgroup reserved space handler
8860          * Page here will be either
8861          * 1) Already written to disk
8862          *    In this case, its reserved space is released from data rsv map
8863          *    and will be freed by delayed_ref handler finally.
8864          *    So even we call qgroup_free_data(), it won't decrease reserved
8865          *    space.
8866          * 2) Not written to disk
8867          *    This means the reserved space should be freed here.
8868          */
8869         btrfs_qgroup_free_data(inode, page_start, PAGE_SIZE);
8870         if (!inode_evicting) {
8871                 clear_extent_bit(tree, page_start, page_end,
8872                                  EXTENT_LOCKED | EXTENT_DIRTY |
8873                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
8874                                  EXTENT_DEFRAG, 1, 1,
8875                                  &cached_state, GFP_NOFS);
8876
8877                 __btrfs_releasepage(page, GFP_NOFS);
8878         }
8879
8880         ClearPageChecked(page);
8881         if (PagePrivate(page)) {
8882                 ClearPagePrivate(page);
8883                 set_page_private(page, 0);
8884                 put_page(page);
8885         }
8886 }
8887
8888 /*
8889  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
8890  * called from a page fault handler when a page is first dirtied. Hence we must
8891  * be careful to check for EOF conditions here. We set the page up correctly
8892  * for a written page which means we get ENOSPC checking when writing into
8893  * holes and correct delalloc and unwritten extent mapping on filesystems that
8894  * support these features.
8895  *
8896  * We are not allowed to take the i_mutex here so we have to play games to
8897  * protect against truncate races as the page could now be beyond EOF.  Because
8898  * vmtruncate() writes the inode size before removing pages, once we have the
8899  * page lock we can determine safely if the page is beyond EOF. If it is not
8900  * beyond EOF, then the page is guaranteed safe against truncation until we
8901  * unlock the page.
8902  */
8903 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
8904 {
8905         struct page *page = vmf->page;
8906         struct inode *inode = file_inode(vma->vm_file);
8907         struct btrfs_root *root = BTRFS_I(inode)->root;
8908         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
8909         struct btrfs_ordered_extent *ordered;
8910         struct extent_state *cached_state = NULL;
8911         char *kaddr;
8912         unsigned long zero_start;
8913         loff_t size;
8914         int ret;
8915         int reserved = 0;
8916         u64 reserved_space;
8917         u64 page_start;
8918         u64 page_end;
8919         u64 end;
8920
8921         reserved_space = PAGE_SIZE;
8922
8923         sb_start_pagefault(inode->i_sb);
8924         page_start = page_offset(page);
8925         page_end = page_start + PAGE_SIZE - 1;
8926         end = page_end;
8927
8928         /*
8929          * Reserving delalloc space after obtaining the page lock can lead to
8930          * deadlock. For example, if a dirty page is locked by this function
8931          * and the call to btrfs_delalloc_reserve_space() ends up triggering
8932          * dirty page write out, then the btrfs_writepage() function could
8933          * end up waiting indefinitely to get a lock on the page currently
8934          * being processed by btrfs_page_mkwrite() function.
8935          */
8936         ret = btrfs_delalloc_reserve_space(inode, page_start,
8937                                            reserved_space);
8938         if (!ret) {
8939                 ret = file_update_time(vma->vm_file);
8940                 reserved = 1;
8941         }
8942         if (ret) {
8943                 if (ret == -ENOMEM)
8944                         ret = VM_FAULT_OOM;
8945                 else /* -ENOSPC, -EIO, etc */
8946                         ret = VM_FAULT_SIGBUS;
8947                 if (reserved)
8948                         goto out;
8949                 goto out_noreserve;
8950         }
8951
8952         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
8953 again:
8954         lock_page(page);
8955         size = i_size_read(inode);
8956
8957         if ((page->mapping != inode->i_mapping) ||
8958             (page_start >= size)) {
8959                 /* page got truncated out from underneath us */
8960                 goto out_unlock;
8961         }
8962         wait_on_page_writeback(page);
8963
8964         lock_extent_bits(io_tree, page_start, page_end, &cached_state);
8965         set_page_extent_mapped(page);
8966
8967         /*
8968          * we can't set the delalloc bits if there are pending ordered
8969          * extents.  Drop our locks and wait for them to finish
8970          */
8971         ordered = btrfs_lookup_ordered_range(inode, page_start, page_end);
8972         if (ordered) {
8973                 unlock_extent_cached(io_tree, page_start, page_end,
8974                                      &cached_state, GFP_NOFS);
8975                 unlock_page(page);
8976                 btrfs_start_ordered_extent(inode, ordered, 1);
8977                 btrfs_put_ordered_extent(ordered);
8978                 goto again;
8979         }
8980
8981         if (page->index == ((size - 1) >> PAGE_SHIFT)) {
8982                 reserved_space = round_up(size - page_start, root->sectorsize);
8983                 if (reserved_space < PAGE_SIZE) {
8984                         end = page_start + reserved_space - 1;
8985                         spin_lock(&BTRFS_I(inode)->lock);
8986                         BTRFS_I(inode)->outstanding_extents++;
8987                         spin_unlock(&BTRFS_I(inode)->lock);
8988                         btrfs_delalloc_release_space(inode, page_start,
8989                                                 PAGE_SIZE - reserved_space);
8990                 }
8991         }
8992
8993         /*
8994          * XXX - page_mkwrite gets called every time the page is dirtied, even
8995          * if it was already dirty, so for space accounting reasons we need to
8996          * clear any delalloc bits for the range we are fixing to save.  There
8997          * is probably a better way to do this, but for now keep consistent with
8998          * prepare_pages in the normal write path.
8999          */
9000         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, end,
9001                           EXTENT_DIRTY | EXTENT_DELALLOC |
9002                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
9003                           0, 0, &cached_state, GFP_NOFS);
9004
9005         ret = btrfs_set_extent_delalloc(inode, page_start, end,
9006                                         &cached_state);
9007         if (ret) {
9008                 unlock_extent_cached(io_tree, page_start, page_end,
9009                                      &cached_state, GFP_NOFS);
9010                 ret = VM_FAULT_SIGBUS;
9011                 goto out_unlock;
9012         }
9013         ret = 0;
9014
9015         /* page is wholly or partially inside EOF */
9016         if (page_start + PAGE_SIZE > size)
9017                 zero_start = size & ~PAGE_MASK;
9018         else
9019                 zero_start = PAGE_SIZE;
9020
9021         if (zero_start != PAGE_SIZE) {
9022                 kaddr = kmap(page);
9023                 memset(kaddr + zero_start, 0, PAGE_SIZE - zero_start);
9024                 flush_dcache_page(page);
9025                 kunmap(page);
9026         }
9027         ClearPageChecked(page);
9028         set_page_dirty(page);
9029         SetPageUptodate(page);
9030
9031         BTRFS_I(inode)->last_trans = root->fs_info->generation;
9032         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
9033         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
9034
9035         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
9036
9037 out_unlock:
9038         if (!ret) {
9039                 sb_end_pagefault(inode->i_sb);
9040                 return VM_FAULT_LOCKED;
9041         }
9042         unlock_page(page);
9043 out:
9044         btrfs_delalloc_release_space(inode, page_start, reserved_space);
9045 out_noreserve:
9046         sb_end_pagefault(inode->i_sb);
9047         return ret;
9048 }
9049
9050 static int btrfs_truncate(struct inode *inode)
9051 {
9052         struct btrfs_root *root = BTRFS_I(inode)->root;
9053         struct btrfs_block_rsv *rsv;
9054         int ret = 0;
9055         int err = 0;
9056         struct btrfs_trans_handle *trans;
9057         u64 mask = root->sectorsize - 1;
9058         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
9059
9060         ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
9061                                        (u64)-1);
9062         if (ret)
9063                 return ret;
9064
9065         /*
9066          * Yes ladies and gentlemen, this is indeed ugly.  The fact is we have
9067          * 3 things going on here
9068          *
9069          * 1) We need to reserve space for our orphan item and the space to
9070          * delete our orphan item.  Lord knows we don't want to have a dangling
9071          * orphan item because we didn't reserve space to remove it.
9072          *
9073          * 2) We need to reserve space to update our inode.
9074          *
9075          * 3) We need to have something to cache all the space that is going to
9076          * be free'd up by the truncate operation, but also have some slack
9077          * space reserved in case it uses space during the truncate (thank you
9078          * very much snapshotting).
9079          *
9080          * And we need these to all be separate.  The fact is we can use a lot of
9081          * space doing the truncate, and we have no earthly idea how much space
9082          * we will use, so we need the truncate reservation to be separate so it
9083          * doesn't end up using space reserved for updating the inode or
9084          * removing the orphan item.  We also need to be able to stop the
9085          * transaction and start a new one, which means we need to be able to
9086          * update the inode several times, and we have no idea of knowing how
9087          * many times that will be, so we can't just reserve 1 item for the
9088          * entirety of the operation, so that has to be done separately as well.
9089          * Then there is the orphan item, which does indeed need to be held on
9090          * to for the whole operation, and we need nobody to touch this reserved
9091          * space except the orphan code.
9092          *
9093          * So that leaves us with
9094          *
9095          * 1) root->orphan_block_rsv - for the orphan deletion.
9096          * 2) rsv - for the truncate reservation, which we will steal from the
9097          * transaction reservation.
9098          * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
9099          * updating the inode.
9100          */
9101         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
9102         if (!rsv)
9103                 return -ENOMEM;
9104         rsv->size = min_size;
9105         rsv->failfast = 1;
9106
9107         /*
9108          * 1 for the truncate slack space
9109          * 1 for updating the inode.
9110          */
9111         trans = btrfs_start_transaction(root, 2);
9112         if (IS_ERR(trans)) {
9113                 err = PTR_ERR(trans);
9114                 goto out;
9115         }
9116
9117         /* Migrate the slack space for the truncate to our reserve */
9118         ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
9119                                       min_size);
9120         BUG_ON(ret);
9121
9122         /*
9123          * So if we truncate and then write and fsync we normally would just
9124          * write the extents that changed, which is a problem if we need to
9125          * first truncate that entire inode.  So set this flag so we write out
9126          * all of the extents in the inode to the sync log so we're completely
9127          * safe.
9128          */
9129         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
9130         trans->block_rsv = rsv;
9131
9132         while (1) {
9133                 ret = btrfs_truncate_inode_items(trans, root, inode,
9134                                                  inode->i_size,
9135                                                  BTRFS_EXTENT_DATA_KEY);
9136                 if (ret != -ENOSPC && ret != -EAGAIN) {
9137                         err = ret;
9138                         break;
9139                 }
9140
9141                 trans->block_rsv = &root->fs_info->trans_block_rsv;
9142                 ret = btrfs_update_inode(trans, root, inode);
9143                 if (ret) {
9144                         err = ret;
9145                         break;
9146                 }
9147
9148                 btrfs_end_transaction(trans, root);
9149                 btrfs_btree_balance_dirty(root);
9150
9151                 trans = btrfs_start_transaction(root, 2);
9152                 if (IS_ERR(trans)) {
9153                         ret = err = PTR_ERR(trans);
9154                         trans = NULL;
9155                         break;
9156                 }
9157
9158                 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
9159                                               rsv, min_size);
9160                 BUG_ON(ret);    /* shouldn't happen */
9161                 trans->block_rsv = rsv;
9162         }
9163
9164         if (ret == 0 && inode->i_nlink > 0) {
9165                 trans->block_rsv = root->orphan_block_rsv;
9166                 ret = btrfs_orphan_del(trans, inode);
9167                 if (ret)
9168                         err = ret;
9169         }
9170
9171         if (trans) {
9172                 trans->block_rsv = &root->fs_info->trans_block_rsv;
9173                 ret = btrfs_update_inode(trans, root, inode);
9174                 if (ret && !err)
9175                         err = ret;
9176
9177                 ret = btrfs_end_transaction(trans, root);
9178                 btrfs_btree_balance_dirty(root);
9179         }
9180
9181 out:
9182         btrfs_free_block_rsv(root, rsv);
9183
9184         if (ret && !err)
9185                 err = ret;
9186
9187         return err;
9188 }
9189
9190 /*
9191  * create a new subvolume directory/inode (helper for the ioctl).
9192  */
9193 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
9194                              struct btrfs_root *new_root,
9195                              struct btrfs_root *parent_root,
9196                              u64 new_dirid)
9197 {
9198         struct inode *inode;
9199         int err;
9200         u64 index = 0;
9201
9202         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
9203                                 new_dirid, new_dirid,
9204                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
9205                                 &index);
9206         if (IS_ERR(inode))
9207                 return PTR_ERR(inode);
9208         inode->i_op = &btrfs_dir_inode_operations;
9209         inode->i_fop = &btrfs_dir_file_operations;
9210
9211         set_nlink(inode, 1);
9212         btrfs_i_size_write(inode, 0);
9213         unlock_new_inode(inode);
9214
9215         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
9216         if (err)
9217                 btrfs_err(new_root->fs_info,
9218                           "error inheriting subvolume %llu properties: %d",
9219                           new_root->root_key.objectid, err);
9220
9221         err = btrfs_update_inode(trans, new_root, inode);
9222
9223         iput(inode);
9224         return err;
9225 }
9226
9227 struct inode *btrfs_alloc_inode(struct super_block *sb)
9228 {
9229         struct btrfs_inode *ei;
9230         struct inode *inode;
9231
9232         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
9233         if (!ei)
9234                 return NULL;
9235
9236         ei->root = NULL;
9237         ei->generation = 0;
9238         ei->last_trans = 0;
9239         ei->last_sub_trans = 0;
9240         ei->logged_trans = 0;
9241         ei->delalloc_bytes = 0;
9242         ei->defrag_bytes = 0;
9243         ei->disk_i_size = 0;
9244         ei->flags = 0;
9245         ei->csum_bytes = 0;
9246         ei->index_cnt = (u64)-1;
9247         ei->dir_index = 0;
9248         ei->last_unlink_trans = 0;
9249         ei->last_log_commit = 0;
9250         ei->delayed_iput_count = 0;
9251
9252         spin_lock_init(&ei->lock);
9253         ei->outstanding_extents = 0;
9254         ei->reserved_extents = 0;
9255
9256         ei->runtime_flags = 0;
9257         ei->force_compress = BTRFS_COMPRESS_NONE;
9258
9259         ei->delayed_node = NULL;
9260
9261         ei->i_otime.tv_sec = 0;
9262         ei->i_otime.tv_nsec = 0;
9263
9264         inode = &ei->vfs_inode;
9265         extent_map_tree_init(&ei->extent_tree);
9266         extent_io_tree_init(&ei->io_tree, &inode->i_data);
9267         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
9268         ei->io_tree.track_uptodate = 1;
9269         ei->io_failure_tree.track_uptodate = 1;
9270         atomic_set(&ei->sync_writers, 0);
9271         mutex_init(&ei->log_mutex);
9272         mutex_init(&ei->delalloc_mutex);
9273         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
9274         INIT_LIST_HEAD(&ei->delalloc_inodes);
9275         INIT_LIST_HEAD(&ei->delayed_iput);
9276         RB_CLEAR_NODE(&ei->rb_node);
9277         init_rwsem(&ei->dio_sem);
9278
9279         return inode;
9280 }
9281
9282 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
9283 void btrfs_test_destroy_inode(struct inode *inode)
9284 {
9285         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
9286         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9287 }
9288 #endif
9289
9290 static void btrfs_i_callback(struct rcu_head *head)
9291 {
9292         struct inode *inode = container_of(head, struct inode, i_rcu);
9293         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
9294 }
9295
9296 void btrfs_destroy_inode(struct inode *inode)
9297 {
9298         struct btrfs_ordered_extent *ordered;
9299         struct btrfs_root *root = BTRFS_I(inode)->root;
9300
9301         WARN_ON(!hlist_empty(&inode->i_dentry));
9302         WARN_ON(inode->i_data.nrpages);
9303         WARN_ON(BTRFS_I(inode)->outstanding_extents);
9304         WARN_ON(BTRFS_I(inode)->reserved_extents);
9305         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
9306         WARN_ON(BTRFS_I(inode)->csum_bytes);
9307         WARN_ON(BTRFS_I(inode)->defrag_bytes);
9308
9309         /*
9310          * This can happen where we create an inode, but somebody else also
9311          * created the same inode and we need to destroy the one we already
9312          * created.
9313          */
9314         if (!root)
9315                 goto free;
9316
9317         if (test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
9318                      &BTRFS_I(inode)->runtime_flags)) {
9319                 btrfs_info(root->fs_info, "inode %llu still on the orphan list",
9320                         btrfs_ino(inode));
9321                 atomic_dec(&root->orphan_inodes);
9322         }
9323
9324         while (1) {
9325                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
9326                 if (!ordered)
9327                         break;
9328                 else {
9329                         btrfs_err(root->fs_info, "found ordered extent %llu %llu on inode cleanup",
9330                                 ordered->file_offset, ordered->len);
9331                         btrfs_remove_ordered_extent(inode, ordered);
9332                         btrfs_put_ordered_extent(ordered);
9333                         btrfs_put_ordered_extent(ordered);
9334                 }
9335         }
9336         btrfs_qgroup_check_reserved_leak(inode);
9337         inode_tree_del(inode);
9338         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
9339 free:
9340         call_rcu(&inode->i_rcu, btrfs_i_callback);
9341 }
9342
9343 int btrfs_drop_inode(struct inode *inode)
9344 {
9345         struct btrfs_root *root = BTRFS_I(inode)->root;
9346
9347         if (root == NULL)
9348                 return 1;
9349
9350         /* the snap/subvol tree is on deleting */
9351         if (btrfs_root_refs(&root->root_item) == 0)
9352                 return 1;
9353         else
9354                 return generic_drop_inode(inode);
9355 }
9356
9357 static void init_once(void *foo)
9358 {
9359         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
9360
9361         inode_init_once(&ei->vfs_inode);
9362 }
9363
9364 void btrfs_destroy_cachep(void)
9365 {
9366         /*
9367          * Make sure all delayed rcu free inodes are flushed before we
9368          * destroy cache.
9369          */
9370         rcu_barrier();
9371         kmem_cache_destroy(btrfs_inode_cachep);
9372         kmem_cache_destroy(btrfs_trans_handle_cachep);
9373         kmem_cache_destroy(btrfs_transaction_cachep);
9374         kmem_cache_destroy(btrfs_path_cachep);
9375         kmem_cache_destroy(btrfs_free_space_cachep);
9376 }
9377
9378 int btrfs_init_cachep(void)
9379 {
9380         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
9381                         sizeof(struct btrfs_inode), 0,
9382                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT,
9383                         init_once);
9384         if (!btrfs_inode_cachep)
9385                 goto fail;
9386
9387         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
9388                         sizeof(struct btrfs_trans_handle), 0,
9389                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9390         if (!btrfs_trans_handle_cachep)
9391                 goto fail;
9392
9393         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
9394                         sizeof(struct btrfs_transaction), 0,
9395                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9396         if (!btrfs_transaction_cachep)
9397                 goto fail;
9398
9399         btrfs_path_cachep = kmem_cache_create("btrfs_path",
9400                         sizeof(struct btrfs_path), 0,
9401                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9402         if (!btrfs_path_cachep)
9403                 goto fail;
9404
9405         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
9406                         sizeof(struct btrfs_free_space), 0,
9407                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
9408         if (!btrfs_free_space_cachep)
9409                 goto fail;
9410
9411         return 0;
9412 fail:
9413         btrfs_destroy_cachep();
9414         return -ENOMEM;
9415 }
9416
9417 static int btrfs_getattr(struct vfsmount *mnt,
9418                          struct dentry *dentry, struct kstat *stat)
9419 {
9420         u64 delalloc_bytes;
9421         struct inode *inode = d_inode(dentry);
9422         u32 blocksize = inode->i_sb->s_blocksize;
9423
9424         generic_fillattr(inode, stat);
9425         stat->dev = BTRFS_I(inode)->root->anon_dev;
9426
9427         spin_lock(&BTRFS_I(inode)->lock);
9428         delalloc_bytes = BTRFS_I(inode)->delalloc_bytes;
9429         spin_unlock(&BTRFS_I(inode)->lock);
9430         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
9431                         ALIGN(delalloc_bytes, blocksize)) >> 9;
9432         return 0;
9433 }
9434
9435 static int btrfs_rename_exchange(struct inode *old_dir,
9436                               struct dentry *old_dentry,
9437                               struct inode *new_dir,
9438                               struct dentry *new_dentry)
9439 {
9440         struct btrfs_trans_handle *trans;
9441         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9442         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9443         struct inode *new_inode = new_dentry->d_inode;
9444         struct inode *old_inode = old_dentry->d_inode;
9445         struct timespec ctime = CURRENT_TIME;
9446         struct dentry *parent;
9447         u64 old_ino = btrfs_ino(old_inode);
9448         u64 new_ino = btrfs_ino(new_inode);
9449         u64 old_idx = 0;
9450         u64 new_idx = 0;
9451         u64 root_objectid;
9452         int ret;
9453         bool root_log_pinned = false;
9454         bool dest_log_pinned = false;
9455
9456         /* we only allow rename subvolume link between subvolumes */
9457         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9458                 return -EXDEV;
9459
9460         /* close the race window with snapshot create/destroy ioctl */
9461         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9462                 down_read(&root->fs_info->subvol_sem);
9463         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9464                 down_read(&dest->fs_info->subvol_sem);
9465
9466         /*
9467          * We want to reserve the absolute worst case amount of items.  So if
9468          * both inodes are subvols and we need to unlink them then that would
9469          * require 4 item modifications, but if they are both normal inodes it
9470          * would require 5 item modifications, so we'll assume their normal
9471          * inodes.  So 5 * 2 is 10, plus 2 for the new links, so 12 total items
9472          * should cover the worst case number of items we'll modify.
9473          */
9474         trans = btrfs_start_transaction(root, 12);
9475         if (IS_ERR(trans)) {
9476                 ret = PTR_ERR(trans);
9477                 goto out_notrans;
9478         }
9479
9480         /*
9481          * We need to find a free sequence number both in the source and
9482          * in the destination directory for the exchange.
9483          */
9484         ret = btrfs_set_inode_index(new_dir, &old_idx);
9485         if (ret)
9486                 goto out_fail;
9487         ret = btrfs_set_inode_index(old_dir, &new_idx);
9488         if (ret)
9489                 goto out_fail;
9490
9491         BTRFS_I(old_inode)->dir_index = 0ULL;
9492         BTRFS_I(new_inode)->dir_index = 0ULL;
9493
9494         /* Reference for the source. */
9495         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9496                 /* force full log commit if subvolume involved. */
9497                 btrfs_set_log_full_commit(root->fs_info, trans);
9498         } else {
9499                 btrfs_pin_log_trans(root);
9500                 root_log_pinned = true;
9501                 ret = btrfs_insert_inode_ref(trans, dest,
9502                                              new_dentry->d_name.name,
9503                                              new_dentry->d_name.len,
9504                                              old_ino,
9505                                              btrfs_ino(new_dir), old_idx);
9506                 if (ret)
9507                         goto out_fail;
9508         }
9509
9510         /* And now for the dest. */
9511         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9512                 /* force full log commit if subvolume involved. */
9513                 btrfs_set_log_full_commit(dest->fs_info, trans);
9514         } else {
9515                 btrfs_pin_log_trans(dest);
9516                 dest_log_pinned = true;
9517                 ret = btrfs_insert_inode_ref(trans, root,
9518                                              old_dentry->d_name.name,
9519                                              old_dentry->d_name.len,
9520                                              new_ino,
9521                                              btrfs_ino(old_dir), new_idx);
9522                 if (ret)
9523                         goto out_fail;
9524         }
9525
9526         /* Update inode version and ctime/mtime. */
9527         inode_inc_iversion(old_dir);
9528         inode_inc_iversion(new_dir);
9529         inode_inc_iversion(old_inode);
9530         inode_inc_iversion(new_inode);
9531         old_dir->i_ctime = old_dir->i_mtime = ctime;
9532         new_dir->i_ctime = new_dir->i_mtime = ctime;
9533         old_inode->i_ctime = ctime;
9534         new_inode->i_ctime = ctime;
9535
9536         if (old_dentry->d_parent != new_dentry->d_parent) {
9537                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
9538                 btrfs_record_unlink_dir(trans, new_dir, new_inode, 1);
9539         }
9540
9541         /* src is a subvolume */
9542         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9543                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9544                 ret = btrfs_unlink_subvol(trans, root, old_dir,
9545                                           root_objectid,
9546                                           old_dentry->d_name.name,
9547                                           old_dentry->d_name.len);
9548         } else { /* src is an inode */
9549                 ret = __btrfs_unlink_inode(trans, root, old_dir,
9550                                            old_dentry->d_inode,
9551                                            old_dentry->d_name.name,
9552                                            old_dentry->d_name.len);
9553                 if (!ret)
9554                         ret = btrfs_update_inode(trans, root, old_inode);
9555         }
9556         if (ret) {
9557                 btrfs_abort_transaction(trans, root, ret);
9558                 goto out_fail;
9559         }
9560
9561         /* dest is a subvolume */
9562         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9563                 root_objectid = BTRFS_I(new_inode)->root->root_key.objectid;
9564                 ret = btrfs_unlink_subvol(trans, dest, new_dir,
9565                                           root_objectid,
9566                                           new_dentry->d_name.name,
9567                                           new_dentry->d_name.len);
9568         } else { /* dest is an inode */
9569                 ret = __btrfs_unlink_inode(trans, dest, new_dir,
9570                                            new_dentry->d_inode,
9571                                            new_dentry->d_name.name,
9572                                            new_dentry->d_name.len);
9573                 if (!ret)
9574                         ret = btrfs_update_inode(trans, dest, new_inode);
9575         }
9576         if (ret) {
9577                 btrfs_abort_transaction(trans, root, ret);
9578                 goto out_fail;
9579         }
9580
9581         ret = btrfs_add_link(trans, new_dir, old_inode,
9582                              new_dentry->d_name.name,
9583                              new_dentry->d_name.len, 0, old_idx);
9584         if (ret) {
9585                 btrfs_abort_transaction(trans, root, ret);
9586                 goto out_fail;
9587         }
9588
9589         ret = btrfs_add_link(trans, old_dir, new_inode,
9590                              old_dentry->d_name.name,
9591                              old_dentry->d_name.len, 0, new_idx);
9592         if (ret) {
9593                 btrfs_abort_transaction(trans, root, ret);
9594                 goto out_fail;
9595         }
9596
9597         if (old_inode->i_nlink == 1)
9598                 BTRFS_I(old_inode)->dir_index = old_idx;
9599         if (new_inode->i_nlink == 1)
9600                 BTRFS_I(new_inode)->dir_index = new_idx;
9601
9602         if (root_log_pinned) {
9603                 parent = new_dentry->d_parent;
9604                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
9605                 btrfs_end_log_trans(root);
9606                 root_log_pinned = false;
9607         }
9608         if (dest_log_pinned) {
9609                 parent = old_dentry->d_parent;
9610                 btrfs_log_new_name(trans, new_inode, new_dir, parent);
9611                 btrfs_end_log_trans(dest);
9612                 dest_log_pinned = false;
9613         }
9614 out_fail:
9615         /*
9616          * If we have pinned a log and an error happened, we unpin tasks
9617          * trying to sync the log and force them to fallback to a transaction
9618          * commit if the log currently contains any of the inodes involved in
9619          * this rename operation (to ensure we do not persist a log with an
9620          * inconsistent state for any of these inodes or leading to any
9621          * inconsistencies when replayed). If the transaction was aborted, the
9622          * abortion reason is propagated to userspace when attempting to commit
9623          * the transaction. If the log does not contain any of these inodes, we
9624          * allow the tasks to sync it.
9625          */
9626         if (ret && (root_log_pinned || dest_log_pinned)) {
9627                 if (btrfs_inode_in_log(old_dir, root->fs_info->generation) ||
9628                     btrfs_inode_in_log(new_dir, root->fs_info->generation) ||
9629                     btrfs_inode_in_log(old_inode, root->fs_info->generation) ||
9630                     (new_inode &&
9631                      btrfs_inode_in_log(new_inode, root->fs_info->generation)))
9632                     btrfs_set_log_full_commit(root->fs_info, trans);
9633
9634                 if (root_log_pinned) {
9635                         btrfs_end_log_trans(root);
9636                         root_log_pinned = false;
9637                 }
9638                 if (dest_log_pinned) {
9639                         btrfs_end_log_trans(dest);
9640                         dest_log_pinned = false;
9641                 }
9642         }
9643         ret = btrfs_end_transaction(trans, root);
9644 out_notrans:
9645         if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
9646                 up_read(&dest->fs_info->subvol_sem);
9647         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9648                 up_read(&root->fs_info->subvol_sem);
9649
9650         return ret;
9651 }
9652
9653 static int btrfs_whiteout_for_rename(struct btrfs_trans_handle *trans,
9654                                      struct btrfs_root *root,
9655                                      struct inode *dir,
9656                                      struct dentry *dentry)
9657 {
9658         int ret;
9659         struct inode *inode;
9660         u64 objectid;
9661         u64 index;
9662
9663         ret = btrfs_find_free_ino(root, &objectid);
9664         if (ret)
9665                 return ret;
9666
9667         inode = btrfs_new_inode(trans, root, dir,
9668                                 dentry->d_name.name,
9669                                 dentry->d_name.len,
9670                                 btrfs_ino(dir),
9671                                 objectid,
9672                                 S_IFCHR | WHITEOUT_MODE,
9673                                 &index);
9674
9675         if (IS_ERR(inode)) {
9676                 ret = PTR_ERR(inode);
9677                 return ret;
9678         }
9679
9680         inode->i_op = &btrfs_special_inode_operations;
9681         init_special_inode(inode, inode->i_mode,
9682                 WHITEOUT_DEV);
9683
9684         ret = btrfs_init_inode_security(trans, inode, dir,
9685                                 &dentry->d_name);
9686         if (ret)
9687                 goto out;
9688
9689         ret = btrfs_add_nondir(trans, dir, dentry,
9690                                 inode, 0, index);
9691         if (ret)
9692                 goto out;
9693
9694         ret = btrfs_update_inode(trans, root, inode);
9695 out:
9696         unlock_new_inode(inode);
9697         if (ret)
9698                 inode_dec_link_count(inode);
9699         iput(inode);
9700
9701         return ret;
9702 }
9703
9704 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
9705                            struct inode *new_dir, struct dentry *new_dentry,
9706                            unsigned int flags)
9707 {
9708         struct btrfs_trans_handle *trans;
9709         unsigned int trans_num_items;
9710         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9711         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9712         struct inode *new_inode = d_inode(new_dentry);
9713         struct inode *old_inode = d_inode(old_dentry);
9714         u64 index = 0;
9715         u64 root_objectid;
9716         int ret;
9717         u64 old_ino = btrfs_ino(old_inode);
9718         bool log_pinned = false;
9719
9720         if (btrfs_ino(new_dir) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
9721                 return -EPERM;
9722
9723         /* we only allow rename subvolume link between subvolumes */
9724         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9725                 return -EXDEV;
9726
9727         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
9728             (new_inode && btrfs_ino(new_inode) == BTRFS_FIRST_FREE_OBJECTID))
9729                 return -ENOTEMPTY;
9730
9731         if (S_ISDIR(old_inode->i_mode) && new_inode &&
9732             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
9733                 return -ENOTEMPTY;
9734
9735
9736         /* check for collisions, even if the  name isn't there */
9737         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
9738                              new_dentry->d_name.name,
9739                              new_dentry->d_name.len);
9740
9741         if (ret) {
9742                 if (ret == -EEXIST) {
9743                         /* we shouldn't get
9744                          * eexist without a new_inode */
9745                         if (WARN_ON(!new_inode)) {
9746                                 return ret;
9747                         }
9748                 } else {
9749                         /* maybe -EOVERFLOW */
9750                         return ret;
9751                 }
9752         }
9753         ret = 0;
9754
9755         /*
9756          * we're using rename to replace one file with another.  Start IO on it
9757          * now so  we don't add too much work to the end of the transaction
9758          */
9759         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
9760                 filemap_flush(old_inode->i_mapping);
9761
9762         /* close the racy window with snapshot create/destroy ioctl */
9763         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9764                 down_read(&root->fs_info->subvol_sem);
9765         /*
9766          * We want to reserve the absolute worst case amount of items.  So if
9767          * both inodes are subvols and we need to unlink them then that would
9768          * require 4 item modifications, but if they are both normal inodes it
9769          * would require 5 item modifications, so we'll assume they are normal
9770          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
9771          * should cover the worst case number of items we'll modify.
9772          * If our rename has the whiteout flag, we need more 5 units for the
9773          * new inode (1 inode item, 1 inode ref, 2 dir items and 1 xattr item
9774          * when selinux is enabled).
9775          */
9776         trans_num_items = 11;
9777         if (flags & RENAME_WHITEOUT)
9778                 trans_num_items += 5;
9779         trans = btrfs_start_transaction(root, trans_num_items);
9780         if (IS_ERR(trans)) {
9781                 ret = PTR_ERR(trans);
9782                 goto out_notrans;
9783         }
9784
9785         if (dest != root)
9786                 btrfs_record_root_in_trans(trans, dest);
9787
9788         ret = btrfs_set_inode_index(new_dir, &index);
9789         if (ret)
9790                 goto out_fail;
9791
9792         BTRFS_I(old_inode)->dir_index = 0ULL;
9793         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9794                 /* force full log commit if subvolume involved. */
9795                 btrfs_set_log_full_commit(root->fs_info, trans);
9796         } else {
9797                 btrfs_pin_log_trans(root);
9798                 log_pinned = true;
9799                 ret = btrfs_insert_inode_ref(trans, dest,
9800                                              new_dentry->d_name.name,
9801                                              new_dentry->d_name.len,
9802                                              old_ino,
9803                                              btrfs_ino(new_dir), index);
9804                 if (ret)
9805                         goto out_fail;
9806         }
9807
9808         inode_inc_iversion(old_dir);
9809         inode_inc_iversion(new_dir);
9810         inode_inc_iversion(old_inode);
9811         old_dir->i_ctime = old_dir->i_mtime =
9812         new_dir->i_ctime = new_dir->i_mtime =
9813         old_inode->i_ctime = current_fs_time(old_dir->i_sb);
9814
9815         if (old_dentry->d_parent != new_dentry->d_parent)
9816                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
9817
9818         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9819                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
9820                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
9821                                         old_dentry->d_name.name,
9822                                         old_dentry->d_name.len);
9823         } else {
9824                 ret = __btrfs_unlink_inode(trans, root, old_dir,
9825                                         d_inode(old_dentry),
9826                                         old_dentry->d_name.name,
9827                                         old_dentry->d_name.len);
9828                 if (!ret)
9829                         ret = btrfs_update_inode(trans, root, old_inode);
9830         }
9831         if (ret) {
9832                 btrfs_abort_transaction(trans, root, ret);
9833                 goto out_fail;
9834         }
9835
9836         if (new_inode) {
9837                 inode_inc_iversion(new_inode);
9838                 new_inode->i_ctime = current_fs_time(new_inode->i_sb);
9839                 if (unlikely(btrfs_ino(new_inode) ==
9840                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
9841                         root_objectid = BTRFS_I(new_inode)->location.objectid;
9842                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
9843                                                 root_objectid,
9844                                                 new_dentry->d_name.name,
9845                                                 new_dentry->d_name.len);
9846                         BUG_ON(new_inode->i_nlink == 0);
9847                 } else {
9848                         ret = btrfs_unlink_inode(trans, dest, new_dir,
9849                                                  d_inode(new_dentry),
9850                                                  new_dentry->d_name.name,
9851                                                  new_dentry->d_name.len);
9852                 }
9853                 if (!ret && new_inode->i_nlink == 0)
9854                         ret = btrfs_orphan_add(trans, d_inode(new_dentry));
9855                 if (ret) {
9856                         btrfs_abort_transaction(trans, root, ret);
9857                         goto out_fail;
9858                 }
9859         }
9860
9861         ret = btrfs_add_link(trans, new_dir, old_inode,
9862                              new_dentry->d_name.name,
9863                              new_dentry->d_name.len, 0, index);
9864         if (ret) {
9865                 btrfs_abort_transaction(trans, root, ret);
9866                 goto out_fail;
9867         }
9868
9869         if (old_inode->i_nlink == 1)
9870                 BTRFS_I(old_inode)->dir_index = index;
9871
9872         if (log_pinned) {
9873                 struct dentry *parent = new_dentry->d_parent;
9874
9875                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
9876                 btrfs_end_log_trans(root);
9877                 log_pinned = false;
9878         }
9879
9880         if (flags & RENAME_WHITEOUT) {
9881                 ret = btrfs_whiteout_for_rename(trans, root, old_dir,
9882                                                 old_dentry);
9883
9884                 if (ret) {
9885                         btrfs_abort_transaction(trans, root, ret);
9886                         goto out_fail;
9887                 }
9888         }
9889 out_fail:
9890         /*
9891          * If we have pinned the log and an error happened, we unpin tasks
9892          * trying to sync the log and force them to fallback to a transaction
9893          * commit if the log currently contains any of the inodes involved in
9894          * this rename operation (to ensure we do not persist a log with an
9895          * inconsistent state for any of these inodes or leading to any
9896          * inconsistencies when replayed). If the transaction was aborted, the
9897          * abortion reason is propagated to userspace when attempting to commit
9898          * the transaction. If the log does not contain any of these inodes, we
9899          * allow the tasks to sync it.
9900          */
9901         if (ret && log_pinned) {
9902                 if (btrfs_inode_in_log(old_dir, root->fs_info->generation) ||
9903                     btrfs_inode_in_log(new_dir, root->fs_info->generation) ||
9904                     btrfs_inode_in_log(old_inode, root->fs_info->generation) ||
9905                     (new_inode &&
9906                      btrfs_inode_in_log(new_inode, root->fs_info->generation)))
9907                     btrfs_set_log_full_commit(root->fs_info, trans);
9908
9909                 btrfs_end_log_trans(root);
9910                 log_pinned = false;
9911         }
9912         btrfs_end_transaction(trans, root);
9913 out_notrans:
9914         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9915                 up_read(&root->fs_info->subvol_sem);
9916
9917         return ret;
9918 }
9919
9920 static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
9921                          struct inode *new_dir, struct dentry *new_dentry,
9922                          unsigned int flags)
9923 {
9924         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
9925                 return -EINVAL;
9926
9927         if (flags & RENAME_EXCHANGE)
9928                 return btrfs_rename_exchange(old_dir, old_dentry, new_dir,
9929                                           new_dentry);
9930
9931         return btrfs_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
9932 }
9933
9934 static void btrfs_run_delalloc_work(struct btrfs_work *work)
9935 {
9936         struct btrfs_delalloc_work *delalloc_work;
9937         struct inode *inode;
9938
9939         delalloc_work = container_of(work, struct btrfs_delalloc_work,
9940                                      work);
9941         inode = delalloc_work->inode;
9942         filemap_flush(inode->i_mapping);
9943         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
9944                                 &BTRFS_I(inode)->runtime_flags))
9945                 filemap_flush(inode->i_mapping);
9946
9947         if (delalloc_work->delay_iput)
9948                 btrfs_add_delayed_iput(inode);
9949         else
9950                 iput(inode);
9951         complete(&delalloc_work->completion);
9952 }
9953
9954 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
9955                                                     int delay_iput)
9956 {
9957         struct btrfs_delalloc_work *work;
9958
9959         work = kmalloc(sizeof(*work), GFP_NOFS);
9960         if (!work)
9961                 return NULL;
9962
9963         init_completion(&work->completion);
9964         INIT_LIST_HEAD(&work->list);
9965         work->inode = inode;
9966         work->delay_iput = delay_iput;
9967         WARN_ON_ONCE(!inode);
9968         btrfs_init_work(&work->work, btrfs_flush_delalloc_helper,
9969                         btrfs_run_delalloc_work, NULL, NULL);
9970
9971         return work;
9972 }
9973
9974 void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
9975 {
9976         wait_for_completion(&work->completion);
9977         kfree(work);
9978 }
9979
9980 /*
9981  * some fairly slow code that needs optimization. This walks the list
9982  * of all the inodes with pending delalloc and forces them to disk.
9983  */
9984 static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
9985                                    int nr)
9986 {
9987         struct btrfs_inode *binode;
9988         struct inode *inode;
9989         struct btrfs_delalloc_work *work, *next;
9990         struct list_head works;
9991         struct list_head splice;
9992         int ret = 0;
9993
9994         INIT_LIST_HEAD(&works);
9995         INIT_LIST_HEAD(&splice);
9996
9997         mutex_lock(&root->delalloc_mutex);
9998         spin_lock(&root->delalloc_lock);
9999         list_splice_init(&root->delalloc_inodes, &splice);
10000         while (!list_empty(&splice)) {
10001                 binode = list_entry(splice.next, struct btrfs_inode,
10002                                     delalloc_inodes);
10003
10004                 list_move_tail(&binode->delalloc_inodes,
10005                                &root->delalloc_inodes);
10006                 inode = igrab(&binode->vfs_inode);
10007                 if (!inode) {
10008                         cond_resched_lock(&root->delalloc_lock);
10009                         continue;
10010                 }
10011                 spin_unlock(&root->delalloc_lock);
10012
10013                 work = btrfs_alloc_delalloc_work(inode, delay_iput);
10014                 if (!work) {
10015                         if (delay_iput)
10016                                 btrfs_add_delayed_iput(inode);
10017                         else
10018                                 iput(inode);
10019                         ret = -ENOMEM;
10020                         goto out;
10021                 }
10022                 list_add_tail(&work->list, &works);
10023                 btrfs_queue_work(root->fs_info->flush_workers,
10024                                  &work->work);
10025                 ret++;
10026                 if (nr != -1 && ret >= nr)
10027                         goto out;
10028                 cond_resched();
10029                 spin_lock(&root->delalloc_lock);
10030         }
10031         spin_unlock(&root->delalloc_lock);
10032
10033 out:
10034         list_for_each_entry_safe(work, next, &works, list) {
10035                 list_del_init(&work->list);
10036                 btrfs_wait_and_free_delalloc_work(work);
10037         }
10038
10039         if (!list_empty_careful(&splice)) {
10040                 spin_lock(&root->delalloc_lock);
10041                 list_splice_tail(&splice, &root->delalloc_inodes);
10042                 spin_unlock(&root->delalloc_lock);
10043         }
10044         mutex_unlock(&root->delalloc_mutex);
10045         return ret;
10046 }
10047
10048 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
10049 {
10050         int ret;
10051
10052         if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
10053                 return -EROFS;
10054
10055         ret = __start_delalloc_inodes(root, delay_iput, -1);
10056         if (ret > 0)
10057                 ret = 0;
10058         /*
10059          * the filemap_flush will queue IO into the worker threads, but
10060          * we have to make sure the IO is actually started and that
10061          * ordered extents get created before we return
10062          */
10063         atomic_inc(&root->fs_info->async_submit_draining);
10064         while (atomic_read(&root->fs_info->nr_async_submits) ||
10065               atomic_read(&root->fs_info->async_delalloc_pages)) {
10066                 wait_event(root->fs_info->async_submit_wait,
10067                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
10068                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
10069         }
10070         atomic_dec(&root->fs_info->async_submit_draining);
10071         return ret;
10072 }
10073
10074 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
10075                                int nr)
10076 {
10077         struct btrfs_root *root;
10078         struct list_head splice;
10079         int ret;
10080
10081         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
10082                 return -EROFS;
10083
10084         INIT_LIST_HEAD(&splice);
10085
10086         mutex_lock(&fs_info->delalloc_root_mutex);
10087         spin_lock(&fs_info->delalloc_root_lock);
10088         list_splice_init(&fs_info->delalloc_roots, &splice);
10089         while (!list_empty(&splice) && nr) {
10090                 root = list_first_entry(&splice, struct btrfs_root,
10091                                         delalloc_root);
10092                 root = btrfs_grab_fs_root(root);
10093                 BUG_ON(!root);
10094                 list_move_tail(&root->delalloc_root,
10095                                &fs_info->delalloc_roots);
10096                 spin_unlock(&fs_info->delalloc_root_lock);
10097
10098                 ret = __start_delalloc_inodes(root, delay_iput, nr);
10099                 btrfs_put_fs_root(root);
10100                 if (ret < 0)
10101                         goto out;
10102
10103                 if (nr != -1) {
10104                         nr -= ret;
10105                         WARN_ON(nr < 0);
10106                 }
10107                 spin_lock(&fs_info->delalloc_root_lock);
10108         }
10109         spin_unlock(&fs_info->delalloc_root_lock);
10110
10111         ret = 0;
10112         atomic_inc(&fs_info->async_submit_draining);
10113         while (atomic_read(&fs_info->nr_async_submits) ||
10114               atomic_read(&fs_info->async_delalloc_pages)) {
10115                 wait_event(fs_info->async_submit_wait,
10116                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
10117                     atomic_read(&fs_info->async_delalloc_pages) == 0));
10118         }
10119         atomic_dec(&fs_info->async_submit_draining);
10120 out:
10121         if (!list_empty_careful(&splice)) {
10122                 spin_lock(&fs_info->delalloc_root_lock);
10123                 list_splice_tail(&splice, &fs_info->delalloc_roots);
10124                 spin_unlock(&fs_info->delalloc_root_lock);
10125         }
10126         mutex_unlock(&fs_info->delalloc_root_mutex);
10127         return ret;
10128 }
10129
10130 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
10131                          const char *symname)
10132 {
10133         struct btrfs_trans_handle *trans;
10134         struct btrfs_root *root = BTRFS_I(dir)->root;
10135         struct btrfs_path *path;
10136         struct btrfs_key key;
10137         struct inode *inode = NULL;
10138         int err;
10139         int drop_inode = 0;
10140         u64 objectid;
10141         u64 index = 0;
10142         int name_len;
10143         int datasize;
10144         unsigned long ptr;
10145         struct btrfs_file_extent_item *ei;
10146         struct extent_buffer *leaf;
10147
10148         name_len = strlen(symname);
10149         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
10150                 return -ENAMETOOLONG;
10151
10152         /*
10153          * 2 items for inode item and ref
10154          * 2 items for dir items
10155          * 1 item for updating parent inode item
10156          * 1 item for the inline extent item
10157          * 1 item for xattr if selinux is on
10158          */
10159         trans = btrfs_start_transaction(root, 7);
10160         if (IS_ERR(trans))
10161                 return PTR_ERR(trans);
10162
10163         err = btrfs_find_free_ino(root, &objectid);
10164         if (err)
10165                 goto out_unlock;
10166
10167         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
10168                                 dentry->d_name.len, btrfs_ino(dir), objectid,
10169                                 S_IFLNK|S_IRWXUGO, &index);
10170         if (IS_ERR(inode)) {
10171                 err = PTR_ERR(inode);
10172                 goto out_unlock;
10173         }
10174
10175         /*
10176         * If the active LSM wants to access the inode during
10177         * d_instantiate it needs these. Smack checks to see
10178         * if the filesystem supports xattrs by looking at the
10179         * ops vector.
10180         */
10181         inode->i_fop = &btrfs_file_operations;
10182         inode->i_op = &btrfs_file_inode_operations;
10183         inode->i_mapping->a_ops = &btrfs_aops;
10184         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10185
10186         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
10187         if (err)
10188                 goto out_unlock_inode;
10189
10190         path = btrfs_alloc_path();
10191         if (!path) {
10192                 err = -ENOMEM;
10193                 goto out_unlock_inode;
10194         }
10195         key.objectid = btrfs_ino(inode);
10196         key.offset = 0;
10197         key.type = BTRFS_EXTENT_DATA_KEY;
10198         datasize = btrfs_file_extent_calc_inline_size(name_len);
10199         err = btrfs_insert_empty_item(trans, root, path, &key,
10200                                       datasize);
10201         if (err) {
10202                 btrfs_free_path(path);
10203                 goto out_unlock_inode;
10204         }
10205         leaf = path->nodes[0];
10206         ei = btrfs_item_ptr(leaf, path->slots[0],
10207                             struct btrfs_file_extent_item);
10208         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
10209         btrfs_set_file_extent_type(leaf, ei,
10210                                    BTRFS_FILE_EXTENT_INLINE);
10211         btrfs_set_file_extent_encryption(leaf, ei, 0);
10212         btrfs_set_file_extent_compression(leaf, ei, 0);
10213         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
10214         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
10215
10216         ptr = btrfs_file_extent_inline_start(ei);
10217         write_extent_buffer(leaf, symname, ptr, name_len);
10218         btrfs_mark_buffer_dirty(leaf);
10219         btrfs_free_path(path);
10220
10221         inode->i_op = &btrfs_symlink_inode_operations;
10222         inode_nohighmem(inode);
10223         inode->i_mapping->a_ops = &btrfs_symlink_aops;
10224         inode_set_bytes(inode, name_len);
10225         btrfs_i_size_write(inode, name_len);
10226         err = btrfs_update_inode(trans, root, inode);
10227         /*
10228          * Last step, add directory indexes for our symlink inode. This is the
10229          * last step to avoid extra cleanup of these indexes if an error happens
10230          * elsewhere above.
10231          */
10232         if (!err)
10233                 err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
10234         if (err) {
10235                 drop_inode = 1;
10236                 goto out_unlock_inode;
10237         }
10238
10239         unlock_new_inode(inode);
10240         d_instantiate(dentry, inode);
10241
10242 out_unlock:
10243         btrfs_end_transaction(trans, root);
10244         if (drop_inode) {
10245                 inode_dec_link_count(inode);
10246                 iput(inode);
10247         }
10248         btrfs_btree_balance_dirty(root);
10249         return err;
10250
10251 out_unlock_inode:
10252         drop_inode = 1;
10253         unlock_new_inode(inode);
10254         goto out_unlock;
10255 }
10256
10257 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
10258                                        u64 start, u64 num_bytes, u64 min_size,
10259                                        loff_t actual_len, u64 *alloc_hint,
10260                                        struct btrfs_trans_handle *trans)
10261 {
10262         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
10263         struct extent_map *em;
10264         struct btrfs_root *root = BTRFS_I(inode)->root;
10265         struct btrfs_key ins;
10266         u64 cur_offset = start;
10267         u64 i_size;
10268         u64 cur_bytes;
10269         u64 last_alloc = (u64)-1;
10270         int ret = 0;
10271         bool own_trans = true;
10272
10273         if (trans)
10274                 own_trans = false;
10275         while (num_bytes > 0) {
10276                 if (own_trans) {
10277                         trans = btrfs_start_transaction(root, 3);
10278                         if (IS_ERR(trans)) {
10279                                 ret = PTR_ERR(trans);
10280                                 break;
10281                         }
10282                 }
10283
10284                 cur_bytes = min_t(u64, num_bytes, SZ_256M);
10285                 cur_bytes = max(cur_bytes, min_size);
10286                 /*
10287                  * If we are severely fragmented we could end up with really
10288                  * small allocations, so if the allocator is returning small
10289                  * chunks lets make its job easier by only searching for those
10290                  * sized chunks.
10291                  */
10292                 cur_bytes = min(cur_bytes, last_alloc);
10293                 ret = btrfs_reserve_extent(root, cur_bytes, min_size, 0,
10294                                            *alloc_hint, &ins, 1, 0);
10295                 if (ret) {
10296                         if (own_trans)
10297                                 btrfs_end_transaction(trans, root);
10298                         break;
10299                 }
10300                 btrfs_dec_block_group_reservations(root->fs_info, ins.objectid);
10301
10302                 last_alloc = ins.offset;
10303                 ret = insert_reserved_file_extent(trans, inode,
10304                                                   cur_offset, ins.objectid,
10305                                                   ins.offset, ins.offset,
10306                                                   ins.offset, 0, 0, 0,
10307                                                   BTRFS_FILE_EXTENT_PREALLOC);
10308                 if (ret) {
10309                         btrfs_free_reserved_extent(root, ins.objectid,
10310                                                    ins.offset, 0);
10311                         btrfs_abort_transaction(trans, root, ret);
10312                         if (own_trans)
10313                                 btrfs_end_transaction(trans, root);
10314                         break;
10315                 }
10316
10317                 btrfs_drop_extent_cache(inode, cur_offset,
10318                                         cur_offset + ins.offset -1, 0);
10319
10320                 em = alloc_extent_map();
10321                 if (!em) {
10322                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
10323                                 &BTRFS_I(inode)->runtime_flags);
10324                         goto next;
10325                 }
10326
10327                 em->start = cur_offset;
10328                 em->orig_start = cur_offset;
10329                 em->len = ins.offset;
10330                 em->block_start = ins.objectid;
10331                 em->block_len = ins.offset;
10332                 em->orig_block_len = ins.offset;
10333                 em->ram_bytes = ins.offset;
10334                 em->bdev = root->fs_info->fs_devices->latest_bdev;
10335                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
10336                 em->generation = trans->transid;
10337
10338                 while (1) {
10339                         write_lock(&em_tree->lock);
10340                         ret = add_extent_mapping(em_tree, em, 1);
10341                         write_unlock(&em_tree->lock);
10342                         if (ret != -EEXIST)
10343                                 break;
10344                         btrfs_drop_extent_cache(inode, cur_offset,
10345                                                 cur_offset + ins.offset - 1,
10346                                                 0);
10347                 }
10348                 free_extent_map(em);
10349 next:
10350                 num_bytes -= ins.offset;
10351                 cur_offset += ins.offset;
10352                 *alloc_hint = ins.objectid + ins.offset;
10353
10354                 inode_inc_iversion(inode);
10355                 inode->i_ctime = current_fs_time(inode->i_sb);
10356                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
10357                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
10358                     (actual_len > inode->i_size) &&
10359                     (cur_offset > inode->i_size)) {
10360                         if (cur_offset > actual_len)
10361                                 i_size = actual_len;
10362                         else
10363                                 i_size = cur_offset;
10364                         i_size_write(inode, i_size);
10365                         btrfs_ordered_update_i_size(inode, i_size, NULL);
10366                 }
10367
10368                 ret = btrfs_update_inode(trans, root, inode);
10369
10370                 if (ret) {
10371                         btrfs_abort_transaction(trans, root, ret);
10372                         if (own_trans)
10373                                 btrfs_end_transaction(trans, root);
10374                         break;
10375                 }
10376
10377                 if (own_trans)
10378                         btrfs_end_transaction(trans, root);
10379         }
10380         return ret;
10381 }
10382
10383 int btrfs_prealloc_file_range(struct inode *inode, int mode,
10384                               u64 start, u64 num_bytes, u64 min_size,
10385                               loff_t actual_len, u64 *alloc_hint)
10386 {
10387         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10388                                            min_size, actual_len, alloc_hint,
10389                                            NULL);
10390 }
10391
10392 int btrfs_prealloc_file_range_trans(struct inode *inode,
10393                                     struct btrfs_trans_handle *trans, int mode,
10394                                     u64 start, u64 num_bytes, u64 min_size,
10395                                     loff_t actual_len, u64 *alloc_hint)
10396 {
10397         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
10398                                            min_size, actual_len, alloc_hint, trans);
10399 }
10400
10401 static int btrfs_set_page_dirty(struct page *page)
10402 {
10403         return __set_page_dirty_nobuffers(page);
10404 }
10405
10406 static int btrfs_permission(struct inode *inode, int mask)
10407 {
10408         struct btrfs_root *root = BTRFS_I(inode)->root;
10409         umode_t mode = inode->i_mode;
10410
10411         if (mask & MAY_WRITE &&
10412             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
10413                 if (btrfs_root_readonly(root))
10414                         return -EROFS;
10415                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
10416                         return -EACCES;
10417         }
10418         return generic_permission(inode, mask);
10419 }
10420
10421 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
10422 {
10423         struct btrfs_trans_handle *trans;
10424         struct btrfs_root *root = BTRFS_I(dir)->root;
10425         struct inode *inode = NULL;
10426         u64 objectid;
10427         u64 index;
10428         int ret = 0;
10429
10430         /*
10431          * 5 units required for adding orphan entry
10432          */
10433         trans = btrfs_start_transaction(root, 5);
10434         if (IS_ERR(trans))
10435                 return PTR_ERR(trans);
10436
10437         ret = btrfs_find_free_ino(root, &objectid);
10438         if (ret)
10439                 goto out;
10440
10441         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
10442                                 btrfs_ino(dir), objectid, mode, &index);
10443         if (IS_ERR(inode)) {
10444                 ret = PTR_ERR(inode);
10445                 inode = NULL;
10446                 goto out;
10447         }
10448
10449         inode->i_fop = &btrfs_file_operations;
10450         inode->i_op = &btrfs_file_inode_operations;
10451
10452         inode->i_mapping->a_ops = &btrfs_aops;
10453         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
10454
10455         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
10456         if (ret)
10457                 goto out_inode;
10458
10459         ret = btrfs_update_inode(trans, root, inode);
10460         if (ret)
10461                 goto out_inode;
10462         ret = btrfs_orphan_add(trans, inode);
10463         if (ret)
10464                 goto out_inode;
10465
10466         /*
10467          * We set number of links to 0 in btrfs_new_inode(), and here we set
10468          * it to 1 because d_tmpfile() will issue a warning if the count is 0,
10469          * through:
10470          *
10471          *    d_tmpfile() -> inode_dec_link_count() -> drop_nlink()
10472          */
10473         set_nlink(inode, 1);
10474         unlock_new_inode(inode);
10475         d_tmpfile(dentry, inode);
10476         mark_inode_dirty(inode);
10477
10478 out:
10479         btrfs_end_transaction(trans, root);
10480         if (ret)
10481                 iput(inode);
10482         btrfs_balance_delayed_items(root);
10483         btrfs_btree_balance_dirty(root);
10484         return ret;
10485
10486 out_inode:
10487         unlock_new_inode(inode);
10488         goto out;
10489
10490 }
10491
10492 /* Inspired by filemap_check_errors() */
10493 int btrfs_inode_check_errors(struct inode *inode)
10494 {
10495         int ret = 0;
10496
10497         if (test_bit(AS_ENOSPC, &inode->i_mapping->flags) &&
10498             test_and_clear_bit(AS_ENOSPC, &inode->i_mapping->flags))
10499                 ret = -ENOSPC;
10500         if (test_bit(AS_EIO, &inode->i_mapping->flags) &&
10501             test_and_clear_bit(AS_EIO, &inode->i_mapping->flags))
10502                 ret = -EIO;
10503
10504         return ret;
10505 }
10506
10507 static const struct inode_operations btrfs_dir_inode_operations = {
10508         .getattr        = btrfs_getattr,
10509         .lookup         = btrfs_lookup,
10510         .create         = btrfs_create,
10511         .unlink         = btrfs_unlink,
10512         .link           = btrfs_link,
10513         .mkdir          = btrfs_mkdir,
10514         .rmdir          = btrfs_rmdir,
10515         .rename2        = btrfs_rename2,
10516         .symlink        = btrfs_symlink,
10517         .setattr        = btrfs_setattr,
10518         .mknod          = btrfs_mknod,
10519         .setxattr       = generic_setxattr,
10520         .getxattr       = generic_getxattr,
10521         .listxattr      = btrfs_listxattr,
10522         .removexattr    = generic_removexattr,
10523         .permission     = btrfs_permission,
10524         .get_acl        = btrfs_get_acl,
10525         .set_acl        = btrfs_set_acl,
10526         .update_time    = btrfs_update_time,
10527         .tmpfile        = btrfs_tmpfile,
10528 };
10529 static const struct inode_operations btrfs_dir_ro_inode_operations = {
10530         .lookup         = btrfs_lookup,
10531         .permission     = btrfs_permission,
10532         .get_acl        = btrfs_get_acl,
10533         .set_acl        = btrfs_set_acl,
10534         .update_time    = btrfs_update_time,
10535 };
10536
10537 static const struct file_operations btrfs_dir_file_operations = {
10538         .llseek         = generic_file_llseek,
10539         .read           = generic_read_dir,
10540         .iterate_shared = btrfs_real_readdir,
10541         .unlocked_ioctl = btrfs_ioctl,
10542 #ifdef CONFIG_COMPAT
10543         .compat_ioctl   = btrfs_compat_ioctl,
10544 #endif
10545         .release        = btrfs_release_file,
10546         .fsync          = btrfs_sync_file,
10547 };
10548
10549 static const struct extent_io_ops btrfs_extent_io_ops = {
10550         .fill_delalloc = run_delalloc_range,
10551         .submit_bio_hook = btrfs_submit_bio_hook,
10552         .merge_bio_hook = btrfs_merge_bio_hook,
10553         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
10554         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
10555         .writepage_start_hook = btrfs_writepage_start_hook,
10556         .set_bit_hook = btrfs_set_bit_hook,
10557         .clear_bit_hook = btrfs_clear_bit_hook,
10558         .merge_extent_hook = btrfs_merge_extent_hook,
10559         .split_extent_hook = btrfs_split_extent_hook,
10560 };
10561
10562 /*
10563  * btrfs doesn't support the bmap operation because swapfiles
10564  * use bmap to make a mapping of extents in the file.  They assume
10565  * these extents won't change over the life of the file and they
10566  * use the bmap result to do IO directly to the drive.
10567  *
10568  * the btrfs bmap call would return logical addresses that aren't
10569  * suitable for IO and they also will change frequently as COW
10570  * operations happen.  So, swapfile + btrfs == corruption.
10571  *
10572  * For now we're avoiding this by dropping bmap.
10573  */
10574 static const struct address_space_operations btrfs_aops = {
10575         .readpage       = btrfs_readpage,
10576         .writepage      = btrfs_writepage,
10577         .writepages     = btrfs_writepages,
10578         .readpages      = btrfs_readpages,
10579         .direct_IO      = btrfs_direct_IO,
10580         .invalidatepage = btrfs_invalidatepage,
10581         .releasepage    = btrfs_releasepage,
10582         .set_page_dirty = btrfs_set_page_dirty,
10583         .error_remove_page = generic_error_remove_page,
10584 };
10585
10586 static const struct address_space_operations btrfs_symlink_aops = {
10587         .readpage       = btrfs_readpage,
10588         .writepage      = btrfs_writepage,
10589         .invalidatepage = btrfs_invalidatepage,
10590         .releasepage    = btrfs_releasepage,
10591 };
10592
10593 static const struct inode_operations btrfs_file_inode_operations = {
10594         .getattr        = btrfs_getattr,
10595         .setattr        = btrfs_setattr,
10596         .setxattr       = generic_setxattr,
10597         .getxattr       = generic_getxattr,
10598         .listxattr      = btrfs_listxattr,
10599         .removexattr    = generic_removexattr,
10600         .permission     = btrfs_permission,
10601         .fiemap         = btrfs_fiemap,
10602         .get_acl        = btrfs_get_acl,
10603         .set_acl        = btrfs_set_acl,
10604         .update_time    = btrfs_update_time,
10605 };
10606 static const struct inode_operations btrfs_special_inode_operations = {
10607         .getattr        = btrfs_getattr,
10608         .setattr        = btrfs_setattr,
10609         .permission     = btrfs_permission,
10610         .setxattr       = generic_setxattr,
10611         .getxattr       = generic_getxattr,
10612         .listxattr      = btrfs_listxattr,
10613         .removexattr    = generic_removexattr,
10614         .get_acl        = btrfs_get_acl,
10615         .set_acl        = btrfs_set_acl,
10616         .update_time    = btrfs_update_time,
10617 };
10618 static const struct inode_operations btrfs_symlink_inode_operations = {
10619         .readlink       = generic_readlink,
10620         .get_link       = page_get_link,
10621         .getattr        = btrfs_getattr,
10622         .setattr        = btrfs_setattr,
10623         .permission     = btrfs_permission,
10624         .setxattr       = generic_setxattr,
10625         .getxattr       = generic_getxattr,
10626         .listxattr      = btrfs_listxattr,
10627         .removexattr    = generic_removexattr,
10628         .update_time    = btrfs_update_time,
10629 };
10630
10631 const struct dentry_operations btrfs_dentry_operations = {
10632         .d_delete       = btrfs_dentry_delete,
10633         .d_release      = btrfs_dentry_release,
10634 };