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/aio.h>
  36 #include <linux/bit_spinlock.h>
  37 #include <linux/xattr.h>
  38 #include <linux/posix_acl.h>
  39 #include <linux/falloc.h>
  40 #include <linux/slab.h>
  41 #include <linux/ratelimit.h>
  42 #include <linux/mount.h>
  43 #include <linux/btrfs.h>
  44 #include <linux/blkdev.h>
  45 #include <linux/posix_acl_xattr.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
  63 struct btrfs_iget_args {
  64         struct btrfs_key *location;
  65         struct btrfs_root *root;
  66 };
  67
  68 static const struct inode_operations btrfs_dir_inode_operations;
  69 static const struct inode_operations btrfs_symlink_inode_operations;
  70 static const struct inode_operations btrfs_dir_ro_inode_operations;
  71 static const struct inode_operations btrfs_special_inode_operations;
  72 static const struct inode_operations btrfs_file_inode_operations;
  73 static const struct address_space_operations btrfs_aops;
  74 static const struct address_space_operations btrfs_symlink_aops;
  75 static const struct file_operations btrfs_dir_file_operations;
  76 static struct extent_io_ops btrfs_extent_io_ops;
  77
  78 static struct kmem_cache *btrfs_inode_cachep;
  79 static struct kmem_cache *btrfs_delalloc_work_cachep;
  80 struct kmem_cache *btrfs_trans_handle_cachep;
  81 struct kmem_cache *btrfs_transaction_cachep;
  82 struct kmem_cache *btrfs_path_cachep;
  83 struct kmem_cache *btrfs_free_space_cachep;
  84
  85 #define S_SHIFT 12
  86 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  87         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  88         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  89         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  90         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  91         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  92         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  93         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  94 };
  95
  96 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
  97 static int btrfs_truncate(struct inode *inode);
  98 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
  99 static noinline int cow_file_range(struct inode *inode,
 100                                    struct page *locked_page,
 101                                    u64 start, u64 end, int *page_started,
 102                                    unsigned long *nr_written, int unlock);
 103 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
 104                                            u64 len, u64 orig_start,
 105                                            u64 block_start, u64 block_len,
 106                                            u64 orig_block_len, u64 ram_bytes,
 107                                            int type);
 108
 109 static int btrfs_dirty_inode(struct inode *inode);
 110
 111 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 112                                      struct inode *inode,  struct inode *dir,
 113                                      const struct qstr *qstr)
 114 {
 115         int err;
 116
 117         err = btrfs_init_acl(trans, inode, dir);
 118         if (!err)
 119                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 120         return err;
 121 }
 122
 123 /*
 124  * this does all the hard work for inserting an inline extent into
 125  * the btree.  The caller should have done a btrfs_drop_extents so that
 126  * no overlapping inline items exist in the btree
 127  */
 128 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
 129                                 struct btrfs_path *path, int extent_inserted,
 130                                 struct btrfs_root *root, struct inode *inode,
 131                                 u64 start, size_t size, size_t compressed_size,
 132                                 int compress_type,
 133                                 struct page **compressed_pages)
 134 {
 135         struct extent_buffer *leaf;
 136         struct page *page = NULL;
 137         char *kaddr;
 138         unsigned long ptr;
 139         struct btrfs_file_extent_item *ei;
 140         int err = 0;
 141         int ret;
 142         size_t cur_size = size;
 143         unsigned long offset;
 144
 145         if (compressed_size && compressed_pages)
 146                 cur_size = compressed_size;
 147
 148         inode_add_bytes(inode, size);
 149
 150         if (!extent_inserted) {
 151                 struct btrfs_key key;
 152                 size_t datasize;
 153
 154                 key.objectid = btrfs_ino(inode);
 155                 key.offset = start;
 156                 btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
 157
 158                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 159                 path->leave_spinning = 1;
 160                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 161                                               datasize);
 162                 if (ret) {
 163                         err = ret;
 164                         goto fail;
 165                 }
 166         }
 167         leaf = path->nodes[0];
 168         ei = btrfs_item_ptr(leaf, path->slots[0],
 169                             struct btrfs_file_extent_item);
 170         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 171         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 172         btrfs_set_file_extent_encryption(leaf, ei, 0);
 173         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 174         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 175         ptr = btrfs_file_extent_inline_start(ei);
 176
 177         if (compress_type != BTRFS_COMPRESS_NONE) {
 178                 struct page *cpage;
 179                 int i = 0;
 180                 while (compressed_size > 0) {
 181                         cpage = compressed_pages[i];
 182                         cur_size = min_t(unsigned long, compressed_size,
 183                                        PAGE_CACHE_SIZE);
 184
 185                         kaddr = kmap_atomic(cpage);
 186                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 187                         kunmap_atomic(kaddr);
 188
 189                         i++;
 190                         ptr += cur_size;
 191                         compressed_size -= cur_size;
 192                 }
 193                 btrfs_set_file_extent_compression(leaf, ei,
 194                                                   compress_type);
 195         } else {
 196                 page = find_get_page(inode->i_mapping,
 197                                      start >> PAGE_CACHE_SHIFT);
 198                 btrfs_set_file_extent_compression(leaf, ei, 0);
 199                 kaddr = kmap_atomic(page);
 200                 offset = start & (PAGE_CACHE_SIZE - 1);
 201                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 202                 kunmap_atomic(kaddr);
 203                 page_cache_release(page);
 204         }
 205         btrfs_mark_buffer_dirty(leaf);
 206         btrfs_release_path(path);
 207
 208         /*
 209          * we're an inline extent, so nobody can
 210          * extend the file past i_size without locking
 211          * a page we already have locked.
 212          *
 213          * We must do any isize and inode updates
 214          * before we unlock the pages.  Otherwise we
 215          * could end up racing with unlink.
 216          */
 217         BTRFS_I(inode)->disk_i_size = inode->i_size;
 218         ret = btrfs_update_inode(trans, root, inode);
 219
 220         return ret;
 221 fail:
 222         return err;
 223 }
 224
 225
 226 /*
 227  * conditionally insert an inline extent into the file.  This
 228  * does the checks required to make sure the data is small enough
 229  * to fit as an inline extent.
 230  */
 231 static noinline int cow_file_range_inline(struct btrfs_root *root,
 232                                           struct inode *inode, u64 start,
 233                                           u64 end, size_t compressed_size,
 234                                           int compress_type,
 235                                           struct page **compressed_pages)
 236 {
 237         struct btrfs_trans_handle *trans;
 238         u64 isize = i_size_read(inode);
 239         u64 actual_end = min(end + 1, isize);
 240         u64 inline_len = actual_end - start;
 241         u64 aligned_end = ALIGN(end, root->sectorsize);
 242         u64 data_len = inline_len;
 243         int ret;
 244         struct btrfs_path *path;
 245         int extent_inserted = 0;
 246         u32 extent_item_size;
 247
 248         if (compressed_size)
 249                 data_len = compressed_size;
 250
 251         if (start > 0 ||
 252             actual_end >= PAGE_CACHE_SIZE ||
 253             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 254             (!compressed_size &&
 255             (actual_end & (root->sectorsize - 1)) == 0) ||
 256             end + 1 < isize ||
 257             data_len > root->fs_info->max_inline) {
 258                 return 1;
 259         }
 260
 261         path = btrfs_alloc_path();
 262         if (!path)
 263                 return -ENOMEM;
 264
 265         trans = btrfs_join_transaction(root);
 266         if (IS_ERR(trans)) {
 267                 btrfs_free_path(path);
 268                 return PTR_ERR(trans);
 269         }
 270         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 271
 272         if (compressed_size && compressed_pages)
 273                 extent_item_size = btrfs_file_extent_calc_inline_size(
 274                    compressed_size);
 275         else
 276                 extent_item_size = btrfs_file_extent_calc_inline_size(
 277                     inline_len);
 278
 279         ret = __btrfs_drop_extents(trans, root, inode, path,
 280                                    start, aligned_end, NULL,
 281                                    1, 1, extent_item_size, &extent_inserted);
 282         if (ret) {
 283                 btrfs_abort_transaction(trans, root, ret);
 284                 goto out;
 285         }
 286
 287         if (isize > actual_end)
 288                 inline_len = min_t(u64, isize, actual_end);
 289         ret = insert_inline_extent(trans, path, extent_inserted,
 290                                    root, inode, start,
 291                                    inline_len, compressed_size,
 292                                    compress_type, compressed_pages);
 293         if (ret && ret != -ENOSPC) {
 294                 btrfs_abort_transaction(trans, root, ret);
 295                 goto out;
 296         } else if (ret == -ENOSPC) {
 297                 ret = 1;
 298                 goto out;
 299         }
 300
 301         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 302         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 303         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 304 out:
 305         btrfs_free_path(path);
 306         btrfs_end_transaction(trans, root);
 307         return ret;
 308 }
 309
 310 struct async_extent {
 311         u64 start;
 312         u64 ram_size;
 313         u64 compressed_size;
 314         struct page **pages;
 315         unsigned long nr_pages;
 316         int compress_type;
 317         struct list_head list;
 318 };
 319
 320 struct async_cow {
 321         struct inode *inode;
 322         struct btrfs_root *root;
 323         struct page *locked_page;
 324         u64 start;
 325         u64 end;
 326         struct list_head extents;
 327         struct btrfs_work work;
 328 };
 329
 330 static noinline int add_async_extent(struct async_cow *cow,
 331                                      u64 start, u64 ram_size,
 332                                      u64 compressed_size,
 333                                      struct page **pages,
 334                                      unsigned long nr_pages,
 335                                      int compress_type)
 336 {
 337         struct async_extent *async_extent;
 338
 339         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 340         BUG_ON(!async_extent); /* -ENOMEM */
 341         async_extent->start = start;
 342         async_extent->ram_size = ram_size;
 343         async_extent->compressed_size = compressed_size;
 344         async_extent->pages = pages;
 345         async_extent->nr_pages = nr_pages;
 346         async_extent->compress_type = compress_type;
 347         list_add_tail(&async_extent->list, &cow->extents);
 348         return 0;
 349 }
 350
 351 /*
 352  * we create compressed extents in two phases.  The first
 353  * phase compresses a range of pages that have already been
 354  * locked (both pages and state bits are locked).
 355  *
 356  * This is done inside an ordered work queue, and the compression
 357  * is spread across many cpus.  The actual IO submission is step
 358  * two, and the ordered work queue takes care of making sure that
 359  * happens in the same order things were put onto the queue by
 360  * writepages and friends.
 361  *
 362  * If this code finds it can't get good compression, it puts an
 363  * entry onto the work queue to write the uncompressed bytes.  This
 364  * makes sure that both compressed inodes and uncompressed inodes
 365  * are written in the same order that the flusher thread sent them
 366  * down.
 367  */
 368 static noinline int compress_file_range(struct inode *inode,
 369                                         struct page *locked_page,
 370                                         u64 start, u64 end,
 371                                         struct async_cow *async_cow,
 372                                         int *num_added)
 373 {
 374         struct btrfs_root *root = BTRFS_I(inode)->root;
 375         u64 num_bytes;
 376         u64 blocksize = root->sectorsize;
 377         u64 actual_end;
 378         u64 isize = i_size_read(inode);
 379         int ret = 0;
 380         struct page **pages = NULL;
 381         unsigned long nr_pages;
 382         unsigned long nr_pages_ret = 0;
 383         unsigned long total_compressed = 0;
 384         unsigned long total_in = 0;
 385         unsigned long max_compressed = 128 * 1024;
 386         unsigned long max_uncompressed = 128 * 1024;
 387         int i;
 388         int will_compress;
 389         int compress_type = root->fs_info->compress_type;
 390         int redirty = 0;
 391
 392         /* if this is a small write inside eof, kick off a defrag */
 393         if ((end - start + 1) < 16 * 1024 &&
 394             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 395                 btrfs_add_inode_defrag(NULL, inode);
 396
 397         /*
 398          * skip compression for a small file range(<=blocksize) that
 399          * isn't an inline extent, since it dosen't save disk space at all.
 400          */
 401         if ((end - start + 1) <= blocksize &&
 402             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 403                 goto cleanup_and_bail_uncompressed;
 404
 405         actual_end = min_t(u64, isize, end + 1);
 406 again:
 407         will_compress = 0;
 408         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
 409         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
 410
 411         /*
 412          * we don't want to send crud past the end of i_size through
 413          * compression, that's just a waste of CPU time.  So, if the
 414          * end of the file is before the start of our current
 415          * requested range of bytes, we bail out to the uncompressed
 416          * cleanup code that can deal with all of this.
 417          *
 418          * It isn't really the fastest way to fix things, but this is a
 419          * very uncommon corner.
 420          */
 421         if (actual_end <= start)
 422                 goto cleanup_and_bail_uncompressed;
 423
 424         total_compressed = actual_end - start;
 425
 426         /* we want to make sure that amount of ram required to uncompress
 427          * an extent is reasonable, so we limit the total size in ram
 428          * of a compressed extent to 128k.  This is a crucial number
 429          * because it also controls how easily we can spread reads across
 430          * cpus for decompression.
 431          *
 432          * We also want to make sure the amount of IO required to do
 433          * a random read is reasonably small, so we limit the size of
 434          * a compressed extent to 128k.
 435          */
 436         total_compressed = min(total_compressed, max_uncompressed);
 437         num_bytes = ALIGN(end - start + 1, blocksize);
 438         num_bytes = max(blocksize,  num_bytes);
 439         total_in = 0;
 440         ret = 0;
 441
 442         /*
 443          * we do compression for mount -o compress and when the
 444          * inode has not been flagged as nocompress.  This flag can
 445          * change at any time if we discover bad compression ratios.
 446          */
 447         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
 448             (btrfs_test_opt(root, COMPRESS) ||
 449              (BTRFS_I(inode)->force_compress) ||
 450              (BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))) {
 451                 WARN_ON(pages);
 452                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
 453                 if (!pages) {
 454                         /* just bail out to the uncompressed code */
 455                         goto cont;
 456                 }
 457
 458                 if (BTRFS_I(inode)->force_compress)
 459                         compress_type = BTRFS_I(inode)->force_compress;
 460
 461                 /*
 462                  * we need to call clear_page_dirty_for_io on each
 463                  * page in the range.  Otherwise applications with the file
 464                  * mmap'd can wander in and change the page contents while
 465                  * we are compressing them.
 466                  *
 467                  * If the compression fails for any reason, we set the pages
 468                  * dirty again later on.
 469                  */
 470                 extent_range_clear_dirty_for_io(inode, start, end);
 471                 redirty = 1;
 472                 ret = btrfs_compress_pages(compress_type,
 473                                            inode->i_mapping, start,
 474                                            total_compressed, pages,
 475                                            nr_pages, &nr_pages_ret,
 476                                            &total_in,
 477                                            &total_compressed,
 478                                            max_compressed);
 479
 480                 if (!ret) {
 481                         unsigned long offset = total_compressed &
 482                                 (PAGE_CACHE_SIZE - 1);
 483                         struct page *page = pages[nr_pages_ret - 1];
 484                         char *kaddr;
 485
 486                         /* zero the tail end of the last page, we might be
 487                          * sending it down to disk
 488                          */
 489                         if (offset) {
 490                                 kaddr = kmap_atomic(page);
 491                                 memset(kaddr + offset, 0,
 492                                        PAGE_CACHE_SIZE - offset);
 493                                 kunmap_atomic(kaddr);
 494                         }
 495                         will_compress = 1;
 496                 }
 497         }
 498 cont:
 499         if (start == 0) {
 500                 /* lets try to make an inline extent */
 501                 if (ret || total_in < (actual_end - start)) {
 502                         /* we didn't compress the entire range, try
 503                          * to make an uncompressed inline extent.
 504                          */
 505                         ret = cow_file_range_inline(root, inode, start, end,
 506                                                     0, 0, NULL);
 507                 } else {
 508                         /* try making a compressed inline extent */
 509                         ret = cow_file_range_inline(root, inode, start, end,
 510                                                     total_compressed,
 511                                                     compress_type, pages);
 512                 }
 513                 if (ret <= 0) {
 514                         unsigned long clear_flags = EXTENT_DELALLOC |
 515                                 EXTENT_DEFRAG;
 516                         clear_flags |= (ret < 0) ? EXTENT_DO_ACCOUNTING : 0;
 517
 518                         /*
 519                          * inline extent creation worked or returned error,
 520                          * we don't need to create any more async work items.
 521                          * Unlock and free up our temp pages.
 522                          */
 523                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 524                                                      clear_flags, PAGE_UNLOCK |
 525                                                      PAGE_CLEAR_DIRTY |
 526                                                      PAGE_SET_WRITEBACK |
 527                                                      PAGE_END_WRITEBACK);
 528                         goto free_pages_out;
 529                 }
 530         }
 531
 532         if (will_compress) {
 533                 /*
 534                  * we aren't doing an inline extent round the compressed size
 535                  * up to a block size boundary so the allocator does sane
 536                  * things
 537                  */
 538                 total_compressed = ALIGN(total_compressed, blocksize);
 539
 540                 /*
 541                  * one last check to make sure the compression is really a
 542                  * win, compare the page count read with the blocks on disk
 543                  */
 544                 total_in = ALIGN(total_in, PAGE_CACHE_SIZE);
 545                 if (total_compressed >= total_in) {
 546                         will_compress = 0;
 547                 } else {
 548                         num_bytes = total_in;
 549                 }
 550         }
 551         if (!will_compress && pages) {
 552                 /*
 553                  * the compression code ran but failed to make things smaller,
 554                  * free any pages it allocated and our page pointer array
 555                  */
 556                 for (i = 0; i < nr_pages_ret; i++) {
 557                         WARN_ON(pages[i]->mapping);
 558                         page_cache_release(pages[i]);
 559                 }
 560                 kfree(pages);
 561                 pages = NULL;
 562                 total_compressed = 0;
 563                 nr_pages_ret = 0;
 564
 565                 /* flag the file so we don't compress in the future */
 566                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
 567                     !(BTRFS_I(inode)->force_compress)) {
 568                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 569                 }
 570         }
 571         if (will_compress) {
 572                 *num_added += 1;
 573
 574                 /* the async work queues will take care of doing actual
 575                  * allocation on disk for these compressed pages,
 576                  * and will submit them to the elevator.
 577                  */
 578                 add_async_extent(async_cow, start, num_bytes,
 579                                  total_compressed, pages, nr_pages_ret,
 580                                  compress_type);
 581
 582                 if (start + num_bytes < end) {
 583                         start += num_bytes;
 584                         pages = NULL;
 585                         cond_resched();
 586                         goto again;
 587                 }
 588         } else {
 589 cleanup_and_bail_uncompressed:
 590                 /*
 591                  * No compression, but we still need to write the pages in
 592                  * the file we've been given so far.  redirty the locked
 593                  * page if it corresponds to our extent and set things up
 594                  * for the async work queue to run cow_file_range to do
 595                  * the normal delalloc dance
 596                  */
 597                 if (page_offset(locked_page) >= start &&
 598                     page_offset(locked_page) <= end) {
 599                         __set_page_dirty_nobuffers(locked_page);
 600                         /* unlocked later on in the async handlers */
 601                 }
 602                 if (redirty)
 603                         extent_range_redirty_for_io(inode, start, end);
 604                 add_async_extent(async_cow, start, end - start + 1,
 605                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
 606                 *num_added += 1;
 607         }
 608
 609 out:
 610         return ret;
 611
 612 free_pages_out:
 613         for (i = 0; i < nr_pages_ret; i++) {
 614                 WARN_ON(pages[i]->mapping);
 615                 page_cache_release(pages[i]);
 616         }
 617         kfree(pages);
 618
 619         goto out;
 620 }
 621
 622 /*
 623  * phase two of compressed writeback.  This is the ordered portion
 624  * of the code, which only gets called in the order the work was
 625  * queued.  We walk all the async extents created by compress_file_range
 626  * and send them down to the disk.
 627  */
 628 static noinline int submit_compressed_extents(struct inode *inode,
 629                                               struct async_cow *async_cow)
 630 {
 631         struct async_extent *async_extent;
 632         u64 alloc_hint = 0;
 633         struct btrfs_key ins;
 634         struct extent_map *em;
 635         struct btrfs_root *root = BTRFS_I(inode)->root;
 636         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 637         struct extent_io_tree *io_tree;
 638         int ret = 0;
 639
 640         if (list_empty(&async_cow->extents))
 641                 return 0;
 642
 643 again:
 644         while (!list_empty(&async_cow->extents)) {
 645                 async_extent = list_entry(async_cow->extents.next,
 646                                           struct async_extent, list);
 647                 list_del(&async_extent->list);
 648
 649                 io_tree = &BTRFS_I(inode)->io_tree;
 650
 651 retry:
 652                 /* did the compression code fall back to uncompressed IO? */
 653                 if (!async_extent->pages) {
 654                         int page_started = 0;
 655                         unsigned long nr_written = 0;
 656
 657                         lock_extent(io_tree, async_extent->start,
 658                                          async_extent->start +
 659                                          async_extent->ram_size - 1);
 660
 661                         /* allocate blocks */
 662                         ret = cow_file_range(inode, async_cow->locked_page,
 663                                              async_extent->start,
 664                                              async_extent->start +
 665                                              async_extent->ram_size - 1,
 666                                              &page_started, &nr_written, 0);
 667
 668                         /* JDM XXX */
 669
 670                         /*
 671                          * if page_started, cow_file_range inserted an
 672                          * inline extent and took care of all the unlocking
 673                          * and IO for us.  Otherwise, we need to submit
 674                          * all those pages down to the drive.
 675                          */
 676                         if (!page_started && !ret)
 677                                 extent_write_locked_range(io_tree,
 678                                                   inode, async_extent->start,
 679                                                   async_extent->start +
 680                                                   async_extent->ram_size - 1,
 681                                                   btrfs_get_extent,
 682                                                   WB_SYNC_ALL);
 683                         else if (ret)
 684                                 unlock_page(async_cow->locked_page);
 685                         kfree(async_extent);
 686                         cond_resched();
 687                         continue;
 688                 }
 689
 690                 lock_extent(io_tree, async_extent->start,
 691                             async_extent->start + async_extent->ram_size - 1);
 692
 693                 ret = btrfs_reserve_extent(root,
 694                                            async_extent->compressed_size,
 695                                            async_extent->compressed_size,
 696                                            0, alloc_hint, &ins, 1);
 697                 if (ret) {
 698                         int i;
 699
 700                         for (i = 0; i < async_extent->nr_pages; i++) {
 701                                 WARN_ON(async_extent->pages[i]->mapping);
 702                                 page_cache_release(async_extent->pages[i]);
 703                         }
 704                         kfree(async_extent->pages);
 705                         async_extent->nr_pages = 0;
 706                         async_extent->pages = NULL;
 707
 708                         if (ret == -ENOSPC) {
 709                                 unlock_extent(io_tree, async_extent->start,
 710                                               async_extent->start +
 711                                               async_extent->ram_size - 1);
 712                                 goto retry;
 713                         }
 714                         goto out_free;
 715                 }
 716
 717                 /*
 718                  * here we're doing allocation and writeback of the
 719                  * compressed pages
 720                  */
 721                 btrfs_drop_extent_cache(inode, async_extent->start,
 722                                         async_extent->start +
 723                                         async_extent->ram_size - 1, 0);
 724
 725                 em = alloc_extent_map();
 726                 if (!em) {
 727                         ret = -ENOMEM;
 728                         goto out_free_reserve;
 729                 }
 730                 em->start = async_extent->start;
 731                 em->len = async_extent->ram_size;
 732                 em->orig_start = em->start;
 733                 em->mod_start = em->start;
 734                 em->mod_len = em->len;
 735
 736                 em->block_start = ins.objectid;
 737                 em->block_len = ins.offset;
 738                 em->orig_block_len = ins.offset;
 739                 em->ram_bytes = async_extent->ram_size;
 740                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 741                 em->compress_type = async_extent->compress_type;
 742                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 743                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 744                 em->generation = -1;
 745
 746                 while (1) {
 747                         write_lock(&em_tree->lock);
 748                         ret = add_extent_mapping(em_tree, em, 1);
 749                         write_unlock(&em_tree->lock);
 750                         if (ret != -EEXIST) {
 751                                 free_extent_map(em);
 752                                 break;
 753                         }
 754                         btrfs_drop_extent_cache(inode, async_extent->start,
 755                                                 async_extent->start +
 756                                                 async_extent->ram_size - 1, 0);
 757                 }
 758
 759                 if (ret)
 760                         goto out_free_reserve;
 761
 762                 ret = btrfs_add_ordered_extent_compress(inode,
 763                                                 async_extent->start,
 764                                                 ins.objectid,
 765                                                 async_extent->ram_size,
 766                                                 ins.offset,
 767                                                 BTRFS_ORDERED_COMPRESSED,
 768                                                 async_extent->compress_type);
 769                 if (ret)
 770                         goto out_free_reserve;
 771
 772                 /*
 773                  * clear dirty, set writeback and unlock the pages.
 774                  */
 775                 extent_clear_unlock_delalloc(inode, async_extent->start,
 776                                 async_extent->start +
 777                                 async_extent->ram_size - 1,
 778                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 779                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 780                                 PAGE_SET_WRITEBACK);
 781                 ret = btrfs_submit_compressed_write(inode,
 782                                     async_extent->start,
 783                                     async_extent->ram_size,
 784                                     ins.objectid,
 785                                     ins.offset, async_extent->pages,
 786                                     async_extent->nr_pages);
 787                 alloc_hint = ins.objectid + ins.offset;
 788                 kfree(async_extent);
 789                 if (ret)
 790                         goto out;
 791                 cond_resched();
 792         }
 793         ret = 0;
 794 out:
 795         return ret;
 796 out_free_reserve:
 797         btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
 798 out_free:
 799         extent_clear_unlock_delalloc(inode, async_extent->start,
 800                                      async_extent->start +
 801                                      async_extent->ram_size - 1,
 802                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 803                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 804                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 805                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
 806         kfree(async_extent);
 807         goto again;
 808 }
 809
 810 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 811                                       u64 num_bytes)
 812 {
 813         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 814         struct extent_map *em;
 815         u64 alloc_hint = 0;
 816
 817         read_lock(&em_tree->lock);
 818         em = search_extent_mapping(em_tree, start, num_bytes);
 819         if (em) {
 820                 /*
 821                  * if block start isn't an actual block number then find the
 822                  * first block in this inode and use that as a hint.  If that
 823                  * block is also bogus then just don't worry about it.
 824                  */
 825                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 826                         free_extent_map(em);
 827                         em = search_extent_mapping(em_tree, 0, 0);
 828                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 829                                 alloc_hint = em->block_start;
 830                         if (em)
 831                                 free_extent_map(em);
 832                 } else {
 833                         alloc_hint = em->block_start;
 834                         free_extent_map(em);
 835                 }
 836         }
 837         read_unlock(&em_tree->lock);
 838
 839         return alloc_hint;
 840 }
 841
 842 /*
 843  * when extent_io.c finds a delayed allocation range in the file,
 844  * the call backs end up in this code.  The basic idea is to
 845  * allocate extents on disk for the range, and create ordered data structs
 846  * in ram to track those extents.
 847  *
 848  * locked_page is the page that writepage had locked already.  We use
 849  * it to make sure we don't do extra locks or unlocks.
 850  *
 851  * *page_started is set to one if we unlock locked_page and do everything
 852  * required to start IO on it.  It may be clean and already done with
 853  * IO when we return.
 854  */
 855 static noinline int cow_file_range(struct inode *inode,
 856                                    struct page *locked_page,
 857                                    u64 start, u64 end, int *page_started,
 858                                    unsigned long *nr_written,
 859                                    int unlock)
 860 {
 861         struct btrfs_root *root = BTRFS_I(inode)->root;
 862         u64 alloc_hint = 0;
 863         u64 num_bytes;
 864         unsigned long ram_size;
 865         u64 disk_num_bytes;
 866         u64 cur_alloc_size;
 867         u64 blocksize = root->sectorsize;
 868         struct btrfs_key ins;
 869         struct extent_map *em;
 870         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 871         int ret = 0;
 872
 873         if (btrfs_is_free_space_inode(inode)) {
 874                 WARN_ON_ONCE(1);
 875                 ret = -EINVAL;
 876                 goto out_unlock;
 877         }
 878
 879         num_bytes = ALIGN(end - start + 1, blocksize);
 880         num_bytes = max(blocksize,  num_bytes);
 881         disk_num_bytes = num_bytes;
 882
 883         /* if this is a small write inside eof, kick off defrag */
 884         if (num_bytes < 64 * 1024 &&
 885             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 886                 btrfs_add_inode_defrag(NULL, inode);
 887
 888         if (start == 0) {
 889                 /* lets try to make an inline extent */
 890                 ret = cow_file_range_inline(root, inode, start, end, 0, 0,
 891                                             NULL);
 892                 if (ret == 0) {
 893                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 894                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 895                                      EXTENT_DEFRAG, PAGE_UNLOCK |
 896                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 897                                      PAGE_END_WRITEBACK);
 898
 899                         *nr_written = *nr_written +
 900                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
 901                         *page_started = 1;
 902                         goto out;
 903                 } else if (ret < 0) {
 904                         goto out_unlock;
 905                 }
 906         }
 907
 908         BUG_ON(disk_num_bytes >
 909                btrfs_super_total_bytes(root->fs_info->super_copy));
 910
 911         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 912         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 913
 914         while (disk_num_bytes > 0) {
 915                 unsigned long op;
 916
 917                 cur_alloc_size = disk_num_bytes;
 918                 ret = btrfs_reserve_extent(root, cur_alloc_size,
 919                                            root->sectorsize, 0, alloc_hint,
 920                                            &ins, 1);
 921                 if (ret < 0)
 922                         goto out_unlock;
 923
 924                 em = alloc_extent_map();
 925                 if (!em) {
 926                         ret = -ENOMEM;
 927                         goto out_reserve;
 928                 }
 929                 em->start = start;
 930                 em->orig_start = em->start;
 931                 ram_size = ins.offset;
 932                 em->len = ins.offset;
 933                 em->mod_start = em->start;
 934                 em->mod_len = em->len;
 935
 936                 em->block_start = ins.objectid;
 937                 em->block_len = ins.offset;
 938                 em->orig_block_len = ins.offset;
 939                 em->ram_bytes = ram_size;
 940                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 941                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 942                 em->generation = -1;
 943
 944                 while (1) {
 945                         write_lock(&em_tree->lock);
 946                         ret = add_extent_mapping(em_tree, em, 1);
 947                         write_unlock(&em_tree->lock);
 948                         if (ret != -EEXIST) {
 949                                 free_extent_map(em);
 950                                 break;
 951                         }
 952                         btrfs_drop_extent_cache(inode, start,
 953                                                 start + ram_size - 1, 0);
 954                 }
 955                 if (ret)
 956                         goto out_reserve;
 957
 958                 cur_alloc_size = ins.offset;
 959                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
 960                                                ram_size, cur_alloc_size, 0);
 961                 if (ret)
 962                         goto out_reserve;
 963
 964                 if (root->root_key.objectid ==
 965                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
 966                         ret = btrfs_reloc_clone_csums(inode, start,
 967                                                       cur_alloc_size);
 968                         if (ret)
 969                                 goto out_reserve;
 970                 }
 971
 972                 if (disk_num_bytes < cur_alloc_size)
 973                         break;
 974
 975                 /* we're not doing compressed IO, don't unlock the first
 976                  * page (which the caller expects to stay locked), don't
 977                  * clear any dirty bits and don't set any writeback bits
 978                  *
 979                  * Do set the Private2 bit so we know this page was properly
 980                  * setup for writepage
 981                  */
 982                 op = unlock ? PAGE_UNLOCK : 0;
 983                 op |= PAGE_SET_PRIVATE2;
 984
 985                 extent_clear_unlock_delalloc(inode, start,
 986                                              start + ram_size - 1, locked_page,
 987                                              EXTENT_LOCKED | EXTENT_DELALLOC,
 988                                              op);
 989                 disk_num_bytes -= cur_alloc_size;
 990                 num_bytes -= cur_alloc_size;
 991                 alloc_hint = ins.objectid + ins.offset;
 992                 start += cur_alloc_size;
 993         }
 994 out:
 995         return ret;
 996
 997 out_reserve:
 998         btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
 999 out_unlock:
1000         extent_clear_unlock_delalloc(inode, start, end, locked_page,
1001                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
1002                                      EXTENT_DELALLOC | EXTENT_DEFRAG,
1003                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
1004                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
1005         goto out;
1006 }
1007
1008 /*
1009  * work queue call back to started compression on a file and pages
1010  */
1011 static noinline void async_cow_start(struct btrfs_work *work)
1012 {
1013         struct async_cow *async_cow;
1014         int num_added = 0;
1015         async_cow = container_of(work, struct async_cow, work);
1016
1017         compress_file_range(async_cow->inode, async_cow->locked_page,
1018                             async_cow->start, async_cow->end, async_cow,
1019                             &num_added);
1020         if (num_added == 0) {
1021                 btrfs_add_delayed_iput(async_cow->inode);
1022                 async_cow->inode = NULL;
1023         }
1024 }
1025
1026 /*
1027  * work queue call back to submit previously compressed pages
1028  */
1029 static noinline void async_cow_submit(struct btrfs_work *work)
1030 {
1031         struct async_cow *async_cow;
1032         struct btrfs_root *root;
1033         unsigned long nr_pages;
1034
1035         async_cow = container_of(work, struct async_cow, work);
1036
1037         root = async_cow->root;
1038         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
1039                 PAGE_CACHE_SHIFT;
1040
1041         if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <
1042             5 * 1024 * 1024 &&
1043             waitqueue_active(&root->fs_info->async_submit_wait))
1044                 wake_up(&root->fs_info->async_submit_wait);
1045
1046         if (async_cow->inode)
1047                 submit_compressed_extents(async_cow->inode, async_cow);
1048 }
1049
1050 static noinline void async_cow_free(struct btrfs_work *work)
1051 {
1052         struct async_cow *async_cow;
1053         async_cow = container_of(work, struct async_cow, work);
1054         if (async_cow->inode)
1055                 btrfs_add_delayed_iput(async_cow->inode);
1056         kfree(async_cow);
1057 }
1058
1059 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1060                                 u64 start, u64 end, int *page_started,
1061                                 unsigned long *nr_written)
1062 {
1063         struct async_cow *async_cow;
1064         struct btrfs_root *root = BTRFS_I(inode)->root;
1065         unsigned long nr_pages;
1066         u64 cur_end;
1067         int limit = 10 * 1024 * 1024;
1068
1069         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1070                          1, 0, NULL, GFP_NOFS);
1071         while (start < end) {
1072                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1073                 BUG_ON(!async_cow); /* -ENOMEM */
1074                 async_cow->inode = igrab(inode);
1075                 async_cow->root = root;
1076                 async_cow->locked_page = locked_page;
1077                 async_cow->start = start;
1078
1079                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
1080                         cur_end = end;
1081                 else
1082                         cur_end = min(end, start + 512 * 1024 - 1);
1083
1084                 async_cow->end = cur_end;
1085                 INIT_LIST_HEAD(&async_cow->extents);
1086
1087                 btrfs_init_work(&async_cow->work, async_cow_start,
1088                                 async_cow_submit, async_cow_free);
1089
1090                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
1091                         PAGE_CACHE_SHIFT;
1092                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
1093
1094                 btrfs_queue_work(root->fs_info->delalloc_workers,
1095                                  &async_cow->work);
1096
1097                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1098                         wait_event(root->fs_info->async_submit_wait,
1099                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1100                             limit));
1101                 }
1102
1103                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1104                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1105                         wait_event(root->fs_info->async_submit_wait,
1106                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1107                            0));
1108                 }
1109
1110                 *nr_written += nr_pages;
1111                 start = cur_end + 1;
1112         }
1113         *page_started = 1;
1114         return 0;
1115 }
1116
1117 static noinline int csum_exist_in_range(struct btrfs_root *root,
1118                                         u64 bytenr, u64 num_bytes)
1119 {
1120         int ret;
1121         struct btrfs_ordered_sum *sums;
1122         LIST_HEAD(list);
1123
1124         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1125                                        bytenr + num_bytes - 1, &list, 0);
1126         if (ret == 0 && list_empty(&list))
1127                 return 0;
1128
1129         while (!list_empty(&list)) {
1130                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1131                 list_del(&sums->list);
1132                 kfree(sums);
1133         }
1134         return 1;
1135 }
1136
1137 /*
1138  * when nowcow writeback call back.  This checks for snapshots or COW copies
1139  * of the extents that exist in the file, and COWs the file as required.
1140  *
1141  * If no cow copies or snapshots exist, we write directly to the existing
1142  * blocks on disk
1143  */
1144 static noinline int run_delalloc_nocow(struct inode *inode,
1145                                        struct page *locked_page,
1146                               u64 start, u64 end, int *page_started, int force,
1147                               unsigned long *nr_written)
1148 {
1149         struct btrfs_root *root = BTRFS_I(inode)->root;
1150         struct btrfs_trans_handle *trans;
1151         struct extent_buffer *leaf;
1152         struct btrfs_path *path;
1153         struct btrfs_file_extent_item *fi;
1154         struct btrfs_key found_key;
1155         u64 cow_start;
1156         u64 cur_offset;
1157         u64 extent_end;
1158         u64 extent_offset;
1159         u64 disk_bytenr;
1160         u64 num_bytes;
1161         u64 disk_num_bytes;
1162         u64 ram_bytes;
1163         int extent_type;
1164         int ret, err;
1165         int type;
1166         int nocow;
1167         int check_prev = 1;
1168         bool nolock;
1169         u64 ino = btrfs_ino(inode);
1170
1171         path = btrfs_alloc_path();
1172         if (!path) {
1173                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1174                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1175                                              EXTENT_DO_ACCOUNTING |
1176                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1177                                              PAGE_CLEAR_DIRTY |
1178                                              PAGE_SET_WRITEBACK |
1179                                              PAGE_END_WRITEBACK);
1180                 return -ENOMEM;
1181         }
1182
1183         nolock = btrfs_is_free_space_inode(inode);
1184
1185         if (nolock)
1186                 trans = btrfs_join_transaction_nolock(root);
1187         else
1188                 trans = btrfs_join_transaction(root);
1189
1190         if (IS_ERR(trans)) {
1191                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1192                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1193                                              EXTENT_DO_ACCOUNTING |
1194                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1195                                              PAGE_CLEAR_DIRTY |
1196                                              PAGE_SET_WRITEBACK |
1197                                              PAGE_END_WRITEBACK);
1198                 btrfs_free_path(path);
1199                 return PTR_ERR(trans);
1200         }
1201
1202         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1203
1204         cow_start = (u64)-1;
1205         cur_offset = start;
1206         while (1) {
1207                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1208                                                cur_offset, 0);
1209                 if (ret < 0)
1210                         goto error;
1211                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1212                         leaf = path->nodes[0];
1213                         btrfs_item_key_to_cpu(leaf, &found_key,
1214                                               path->slots[0] - 1);
1215                         if (found_key.objectid == ino &&
1216                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1217                                 path->slots[0]--;
1218                 }
1219                 check_prev = 0;
1220 next_slot:
1221                 leaf = path->nodes[0];
1222                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1223                         ret = btrfs_next_leaf(root, path);
1224                         if (ret < 0)
1225                                 goto error;
1226                         if (ret > 0)
1227                                 break;
1228                         leaf = path->nodes[0];
1229                 }
1230
1231                 nocow = 0;
1232                 disk_bytenr = 0;
1233                 num_bytes = 0;
1234                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1235
1236                 if (found_key.objectid > ino ||
1237                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1238                     found_key.offset > end)
1239                         break;
1240
1241                 if (found_key.offset > cur_offset) {
1242                         extent_end = found_key.offset;
1243                         extent_type = 0;
1244                         goto out_check;
1245                 }
1246
1247                 fi = btrfs_item_ptr(leaf, path->slots[0],
1248                                     struct btrfs_file_extent_item);
1249                 extent_type = btrfs_file_extent_type(leaf, fi);
1250
1251                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1252                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1253                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1254                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1255                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1256                         extent_end = found_key.offset +
1257                                 btrfs_file_extent_num_bytes(leaf, fi);
1258                         disk_num_bytes =
1259                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1260                         if (extent_end <= start) {
1261                                 path->slots[0]++;
1262                                 goto next_slot;
1263                         }
1264                         if (disk_bytenr == 0)
1265                                 goto out_check;
1266                         if (btrfs_file_extent_compression(leaf, fi) ||
1267                             btrfs_file_extent_encryption(leaf, fi) ||
1268                             btrfs_file_extent_other_encoding(leaf, fi))
1269                                 goto out_check;
1270                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1271                                 goto out_check;
1272                         if (btrfs_extent_readonly(root, disk_bytenr))
1273                                 goto out_check;
1274                         if (btrfs_cross_ref_exist(trans, root, ino,
1275                                                   found_key.offset -
1276                                                   extent_offset, disk_bytenr))
1277                                 goto out_check;
1278                         disk_bytenr += extent_offset;
1279                         disk_bytenr += cur_offset - found_key.offset;
1280                         num_bytes = min(end + 1, extent_end) - cur_offset;
1281                         /*
1282                          * if there are pending snapshots for this root,
1283                          * we fall into common COW way.
1284                          */
1285                         if (!nolock) {
1286                                 err = btrfs_start_nocow_write(root);
1287                                 if (!err)
1288                                         goto out_check;
1289                         }
1290                         /*
1291                          * force cow if csum exists in the range.
1292                          * this ensure that csum for a given extent are
1293                          * either valid or do not exist.
1294                          */
1295                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1296                                 goto out_check;
1297                         nocow = 1;
1298                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1299                         extent_end = found_key.offset +
1300                                 btrfs_file_extent_inline_len(leaf,
1301                                                      path->slots[0], fi);
1302                         extent_end = ALIGN(extent_end, root->sectorsize);
1303                 } else {
1304                         BUG_ON(1);
1305                 }
1306 out_check:
1307                 if (extent_end <= start) {
1308                         path->slots[0]++;
1309                         if (!nolock && nocow)
1310                                 btrfs_end_nocow_write(root);
1311                         goto next_slot;
1312                 }
1313                 if (!nocow) {
1314                         if (cow_start == (u64)-1)
1315                                 cow_start = cur_offset;
1316                         cur_offset = extent_end;
1317                         if (cur_offset > end)
1318                                 break;
1319                         path->slots[0]++;
1320                         goto next_slot;
1321                 }
1322
1323                 btrfs_release_path(path);
1324                 if (cow_start != (u64)-1) {
1325                         ret = cow_file_range(inode, locked_page,
1326                                              cow_start, found_key.offset - 1,
1327                                              page_started, nr_written, 1);
1328                         if (ret) {
1329                                 if (!nolock && nocow)
1330                                         btrfs_end_nocow_write(root);
1331                                 goto error;
1332                         }
1333                         cow_start = (u64)-1;
1334                 }
1335
1336                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1337                         struct extent_map *em;
1338                         struct extent_map_tree *em_tree;
1339                         em_tree = &BTRFS_I(inode)->extent_tree;
1340                         em = alloc_extent_map();
1341                         BUG_ON(!em); /* -ENOMEM */
1342                         em->start = cur_offset;
1343                         em->orig_start = found_key.offset - extent_offset;
1344                         em->len = num_bytes;
1345                         em->block_len = num_bytes;
1346                         em->block_start = disk_bytenr;
1347                         em->orig_block_len = disk_num_bytes;
1348                         em->ram_bytes = ram_bytes;
1349                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1350                         em->mod_start = em->start;
1351                         em->mod_len = em->len;
1352                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1353                         set_bit(EXTENT_FLAG_FILLING, &em->flags);
1354                         em->generation = -1;
1355                         while (1) {
1356                                 write_lock(&em_tree->lock);
1357                                 ret = add_extent_mapping(em_tree, em, 1);
1358                                 write_unlock(&em_tree->lock);
1359                                 if (ret != -EEXIST) {
1360                                         free_extent_map(em);
1361                                         break;
1362                                 }
1363                                 btrfs_drop_extent_cache(inode, em->start,
1364                                                 em->start + em->len - 1, 0);
1365                         }
1366                         type = BTRFS_ORDERED_PREALLOC;
1367                 } else {
1368                         type = BTRFS_ORDERED_NOCOW;
1369                 }
1370
1371                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1372                                                num_bytes, num_bytes, type);
1373                 BUG_ON(ret); /* -ENOMEM */
1374
1375                 if (root->root_key.objectid ==
1376                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1377                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1378                                                       num_bytes);
1379                         if (ret) {
1380                                 if (!nolock && nocow)
1381                                         btrfs_end_nocow_write(root);
1382                                 goto error;
1383                         }
1384                 }
1385
1386                 extent_clear_unlock_delalloc(inode, cur_offset,
1387                                              cur_offset + num_bytes - 1,
1388                                              locked_page, EXTENT_LOCKED |
1389                                              EXTENT_DELALLOC, PAGE_UNLOCK |
1390                                              PAGE_SET_PRIVATE2);
1391                 if (!nolock && nocow)
1392                         btrfs_end_nocow_write(root);
1393                 cur_offset = extent_end;
1394                 if (cur_offset > end)
1395                         break;
1396         }
1397         btrfs_release_path(path);
1398
1399         if (cur_offset <= end && cow_start == (u64)-1) {
1400                 cow_start = cur_offset;
1401                 cur_offset = end;
1402         }
1403
1404         if (cow_start != (u64)-1) {
1405                 ret = cow_file_range(inode, locked_page, cow_start, end,
1406                                      page_started, nr_written, 1);
1407                 if (ret)
1408                         goto error;
1409         }
1410
1411 error:
1412         err = btrfs_end_transaction(trans, root);
1413         if (!ret)
1414                 ret = err;
1415
1416         if (ret && cur_offset < end)
1417                 extent_clear_unlock_delalloc(inode, cur_offset, end,
1418                                              locked_page, EXTENT_LOCKED |
1419                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1420                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1421                                              PAGE_CLEAR_DIRTY |
1422                                              PAGE_SET_WRITEBACK |
1423                                              PAGE_END_WRITEBACK);
1424         btrfs_free_path(path);
1425         return ret;
1426 }
1427
1428 /*
1429  * extent_io.c call back to do delayed allocation processing
1430  */
1431 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1432                               u64 start, u64 end, int *page_started,
1433                               unsigned long *nr_written)
1434 {
1435         int ret;
1436         struct btrfs_root *root = BTRFS_I(inode)->root;
1437
1438         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) {
1439                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1440                                          page_started, 1, nr_written);
1441         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC) {
1442                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1443                                          page_started, 0, nr_written);
1444         } else if (!btrfs_test_opt(root, COMPRESS) &&
1445                    !(BTRFS_I(inode)->force_compress) &&
1446                    !(BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS)) {
1447                 ret = cow_file_range(inode, locked_page, start, end,
1448                                       page_started, nr_written, 1);
1449         } else {
1450                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1451                         &BTRFS_I(inode)->runtime_flags);
1452                 ret = cow_file_range_async(inode, locked_page, start, end,
1453                                            page_started, nr_written);
1454         }
1455         return ret;
1456 }
1457
1458 static void btrfs_split_extent_hook(struct inode *inode,
1459                                     struct extent_state *orig, u64 split)
1460 {
1461         /* not delalloc, ignore it */
1462         if (!(orig->state & EXTENT_DELALLOC))
1463                 return;
1464
1465         spin_lock(&BTRFS_I(inode)->lock);
1466         BTRFS_I(inode)->outstanding_extents++;
1467         spin_unlock(&BTRFS_I(inode)->lock);
1468 }
1469
1470 /*
1471  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1472  * extents so we can keep track of new extents that are just merged onto old
1473  * extents, such as when we are doing sequential writes, so we can properly
1474  * account for the metadata space we'll need.
1475  */
1476 static void btrfs_merge_extent_hook(struct inode *inode,
1477                                     struct extent_state *new,
1478                                     struct extent_state *other)
1479 {
1480         /* not delalloc, ignore it */
1481         if (!(other->state & EXTENT_DELALLOC))
1482                 return;
1483
1484         spin_lock(&BTRFS_I(inode)->lock);
1485         BTRFS_I(inode)->outstanding_extents--;
1486         spin_unlock(&BTRFS_I(inode)->lock);
1487 }
1488
1489 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1490                                       struct inode *inode)
1491 {
1492         spin_lock(&root->delalloc_lock);
1493         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1494                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1495                               &root->delalloc_inodes);
1496                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1497                         &BTRFS_I(inode)->runtime_flags);
1498                 root->nr_delalloc_inodes++;
1499                 if (root->nr_delalloc_inodes == 1) {
1500                         spin_lock(&root->fs_info->delalloc_root_lock);
1501                         BUG_ON(!list_empty(&root->delalloc_root));
1502                         list_add_tail(&root->delalloc_root,
1503                                       &root->fs_info->delalloc_roots);
1504                         spin_unlock(&root->fs_info->delalloc_root_lock);
1505                 }
1506         }
1507         spin_unlock(&root->delalloc_lock);
1508 }
1509
1510 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1511                                      struct inode *inode)
1512 {
1513         spin_lock(&root->delalloc_lock);
1514         if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1515                 list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1516                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1517                           &BTRFS_I(inode)->runtime_flags);
1518                 root->nr_delalloc_inodes--;
1519                 if (!root->nr_delalloc_inodes) {
1520                         spin_lock(&root->fs_info->delalloc_root_lock);
1521                         BUG_ON(list_empty(&root->delalloc_root));
1522                         list_del_init(&root->delalloc_root);
1523                         spin_unlock(&root->fs_info->delalloc_root_lock);
1524                 }
1525         }
1526         spin_unlock(&root->delalloc_lock);
1527 }
1528
1529 /*
1530  * extent_io.c set_bit_hook, used to track delayed allocation
1531  * bytes in this file, and to maintain the list of inodes that
1532  * have pending delalloc work to be done.
1533  */
1534 static void btrfs_set_bit_hook(struct inode *inode,
1535                                struct extent_state *state, unsigned long *bits)
1536 {
1537
1538         /*
1539          * set_bit and clear bit hooks normally require _irqsave/restore
1540          * but in this case, we are only testing for the DELALLOC
1541          * bit, which is only set or cleared with irqs on
1542          */
1543         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1544                 struct btrfs_root *root = BTRFS_I(inode)->root;
1545                 u64 len = state->end + 1 - state->start;
1546                 bool do_list = !btrfs_is_free_space_inode(inode);
1547
1548                 if (*bits & EXTENT_FIRST_DELALLOC) {
1549                         *bits &= ~EXTENT_FIRST_DELALLOC;
1550                 } else {
1551                         spin_lock(&BTRFS_I(inode)->lock);
1552                         BTRFS_I(inode)->outstanding_extents++;
1553                         spin_unlock(&BTRFS_I(inode)->lock);
1554                 }
1555
1556                 __percpu_counter_add(&root->fs_info->delalloc_bytes, len,
1557                                      root->fs_info->delalloc_batch);
1558                 spin_lock(&BTRFS_I(inode)->lock);
1559                 BTRFS_I(inode)->delalloc_bytes += len;
1560                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1561                                          &BTRFS_I(inode)->runtime_flags))
1562                         btrfs_add_delalloc_inodes(root, inode);
1563                 spin_unlock(&BTRFS_I(inode)->lock);
1564         }
1565 }
1566
1567 /*
1568  * extent_io.c clear_bit_hook, see set_bit_hook for why
1569  */
1570 static void btrfs_clear_bit_hook(struct inode *inode,
1571                                  struct extent_state *state,
1572                                  unsigned long *bits)
1573 {
1574         /*
1575          * set_bit and clear bit hooks normally require _irqsave/restore
1576          * but in this case, we are only testing for the DELALLOC
1577          * bit, which is only set or cleared with irqs on
1578          */
1579         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1580                 struct btrfs_root *root = BTRFS_I(inode)->root;
1581                 u64 len = state->end + 1 - state->start;
1582                 bool do_list = !btrfs_is_free_space_inode(inode);
1583
1584                 if (*bits & EXTENT_FIRST_DELALLOC) {
1585                         *bits &= ~EXTENT_FIRST_DELALLOC;
1586                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1587                         spin_lock(&BTRFS_I(inode)->lock);
1588                         BTRFS_I(inode)->outstanding_extents--;
1589                         spin_unlock(&BTRFS_I(inode)->lock);
1590                 }
1591
1592                 /*
1593                  * We don't reserve metadata space for space cache inodes so we
1594                  * don't need to call dellalloc_release_metadata if there is an
1595                  * error.
1596                  */
1597                 if (*bits & EXTENT_DO_ACCOUNTING &&
1598                     root != root->fs_info->tree_root)
1599                         btrfs_delalloc_release_metadata(inode, len);
1600
1601                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1602                     && do_list && !(state->state & EXTENT_NORESERVE))
1603                         btrfs_free_reserved_data_space(inode, len);
1604
1605                 __percpu_counter_add(&root->fs_info->delalloc_bytes, -len,
1606                                      root->fs_info->delalloc_batch);
1607                 spin_lock(&BTRFS_I(inode)->lock);
1608                 BTRFS_I(inode)->delalloc_bytes -= len;
1609                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1610                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1611                              &BTRFS_I(inode)->runtime_flags))
1612                         btrfs_del_delalloc_inode(root, inode);
1613                 spin_unlock(&BTRFS_I(inode)->lock);
1614         }
1615 }
1616
1617 /*
1618  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1619  * we don't create bios that span stripes or chunks
1620  */
1621 int btrfs_merge_bio_hook(int rw, struct page *page, unsigned long offset,
1622                          size_t size, struct bio *bio,
1623                          unsigned long bio_flags)
1624 {
1625         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1626         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1627         u64 length = 0;
1628         u64 map_length;
1629         int ret;
1630
1631         if (bio_flags & EXTENT_BIO_COMPRESSED)
1632                 return 0;
1633
1634         length = bio->bi_iter.bi_size;
1635         map_length = length;
1636         ret = btrfs_map_block(root->fs_info, rw, logical,
1637                               &map_length, NULL, 0);
1638         /* Will always return 0 with map_multi == NULL */
1639         BUG_ON(ret < 0);
1640         if (map_length < length + size)
1641                 return 1;
1642         return 0;
1643 }
1644
1645 /*
1646  * in order to insert checksums into the metadata in large chunks,
1647  * we wait until bio submission time.   All the pages in the bio are
1648  * checksummed and sums are attached onto the ordered extent record.
1649  *
1650  * At IO completion time the cums attached on the ordered extent record
1651  * are inserted into the btree
1652  */
1653 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1654                                     struct bio *bio, int mirror_num,
1655                                     unsigned long bio_flags,
1656                                     u64 bio_offset)
1657 {
1658         struct btrfs_root *root = BTRFS_I(inode)->root;
1659         int ret = 0;
1660
1661         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1662         BUG_ON(ret); /* -ENOMEM */
1663         return 0;
1664 }
1665
1666 /*
1667  * in order to insert checksums into the metadata in large chunks,
1668  * we wait until bio submission time.   All the pages in the bio are
1669  * checksummed and sums are attached onto the ordered extent record.
1670  *
1671  * At IO completion time the cums attached on the ordered extent record
1672  * are inserted into the btree
1673  */
1674 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1675                           int mirror_num, unsigned long bio_flags,
1676                           u64 bio_offset)
1677 {
1678         struct btrfs_root *root = BTRFS_I(inode)->root;
1679         int ret;
1680
1681         ret = btrfs_map_bio(root, rw, bio, mirror_num, 1);
1682         if (ret)
1683                 bio_endio(bio, ret);
1684         return ret;
1685 }
1686
1687 /*
1688  * extent_io.c submission hook. This does the right thing for csum calculation
1689  * on write, or reading the csums from the tree before a read
1690  */
1691 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1692                           int mirror_num, unsigned long bio_flags,
1693                           u64 bio_offset)
1694 {
1695         struct btrfs_root *root = BTRFS_I(inode)->root;
1696         int ret = 0;
1697         int skip_sum;
1698         int metadata = 0;
1699         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1700
1701         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1702
1703         if (btrfs_is_free_space_inode(inode))
1704                 metadata = 2;
1705
1706         if (!(rw & REQ_WRITE)) {
1707                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, metadata);
1708                 if (ret)
1709                         goto out;
1710
1711                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1712                         ret = btrfs_submit_compressed_read(inode, bio,
1713                                                            mirror_num,
1714                                                            bio_flags);
1715                         goto out;
1716                 } else if (!skip_sum) {
1717                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1718                         if (ret)
1719                                 goto out;
1720                 }
1721                 goto mapit;
1722         } else if (async && !skip_sum) {
1723                 /* csum items have already been cloned */
1724                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1725                         goto mapit;
1726                 /* we're doing a write, do the async checksumming */
1727                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1728                                    inode, rw, bio, mirror_num,
1729                                    bio_flags, bio_offset,
1730                                    __btrfs_submit_bio_start,
1731                                    __btrfs_submit_bio_done);
1732                 goto out;
1733         } else if (!skip_sum) {
1734                 ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1735                 if (ret)
1736                         goto out;
1737         }
1738
1739 mapit:
1740         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
1741
1742 out:
1743         if (ret < 0)
1744                 bio_endio(bio, ret);
1745         return ret;
1746 }
1747
1748 /*
1749  * given a list of ordered sums record them in the inode.  This happens
1750  * at IO completion time based on sums calculated at bio submission time.
1751  */
1752 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1753                              struct inode *inode, u64 file_offset,
1754                              struct list_head *list)
1755 {
1756         struct btrfs_ordered_sum *sum;
1757
1758         list_for_each_entry(sum, list, list) {
1759                 trans->adding_csums = 1;
1760                 btrfs_csum_file_blocks(trans,
1761                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1762                 trans->adding_csums = 0;
1763         }
1764         return 0;
1765 }
1766
1767 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1768                               struct extent_state **cached_state)
1769 {
1770         WARN_ON((end & (PAGE_CACHE_SIZE - 1)) == 0);
1771         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1772                                    cached_state, GFP_NOFS);
1773 }
1774
1775 /* see btrfs_writepage_start_hook for details on why this is required */
1776 struct btrfs_writepage_fixup {
1777         struct page *page;
1778         struct btrfs_work work;
1779 };
1780
1781 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1782 {
1783         struct btrfs_writepage_fixup *fixup;
1784         struct btrfs_ordered_extent *ordered;
1785         struct extent_state *cached_state = NULL;
1786         struct page *page;
1787         struct inode *inode;
1788         u64 page_start;
1789         u64 page_end;
1790         int ret;
1791
1792         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1793         page = fixup->page;
1794 again:
1795         lock_page(page);
1796         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1797                 ClearPageChecked(page);
1798                 goto out_page;
1799         }
1800
1801         inode = page->mapping->host;
1802         page_start = page_offset(page);
1803         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1804
1805         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1806                          &cached_state);
1807
1808         /* already ordered? We're done */
1809         if (PagePrivate2(page))
1810                 goto out;
1811
1812         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1813         if (ordered) {
1814                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1815                                      page_end, &cached_state, GFP_NOFS);
1816                 unlock_page(page);
1817                 btrfs_start_ordered_extent(inode, ordered, 1);
1818                 btrfs_put_ordered_extent(ordered);
1819                 goto again;
1820         }
1821
1822         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
1823         if (ret) {
1824                 mapping_set_error(page->mapping, ret);
1825                 end_extent_writepage(page, ret, page_start, page_end);
1826                 ClearPageChecked(page);
1827                 goto out;
1828          }
1829
1830         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1831         ClearPageChecked(page);
1832         set_page_dirty(page);
1833 out:
1834         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1835                              &cached_state, GFP_NOFS);
1836 out_page:
1837         unlock_page(page);
1838         page_cache_release(page);
1839         kfree(fixup);
1840 }
1841
1842 /*
1843  * There are a few paths in the higher layers of the kernel that directly
1844  * set the page dirty bit without asking the filesystem if it is a
1845  * good idea.  This causes problems because we want to make sure COW
1846  * properly happens and the data=ordered rules are followed.
1847  *
1848  * In our case any range that doesn't have the ORDERED bit set
1849  * hasn't been properly setup for IO.  We kick off an async process
1850  * to fix it up.  The async helper will wait for ordered extents, set
1851  * the delalloc bit and make it safe to write the page.
1852  */
1853 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1854 {
1855         struct inode *inode = page->mapping->host;
1856         struct btrfs_writepage_fixup *fixup;
1857         struct btrfs_root *root = BTRFS_I(inode)->root;
1858
1859         /* this page is properly in the ordered list */
1860         if (TestClearPagePrivate2(page))
1861                 return 0;
1862
1863         if (PageChecked(page))
1864                 return -EAGAIN;
1865
1866         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1867         if (!fixup)
1868                 return -EAGAIN;
1869
1870         SetPageChecked(page);
1871         page_cache_get(page);
1872         btrfs_init_work(&fixup->work, btrfs_writepage_fixup_worker, NULL, NULL);
1873         fixup->page = page;
1874         btrfs_queue_work(root->fs_info->fixup_workers, &fixup->work);
1875         return -EBUSY;
1876 }
1877
1878 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1879                                        struct inode *inode, u64 file_pos,
1880                                        u64 disk_bytenr, u64 disk_num_bytes,
1881                                        u64 num_bytes, u64 ram_bytes,
1882                                        u8 compression, u8 encryption,
1883                                        u16 other_encoding, int extent_type)
1884 {
1885         struct btrfs_root *root = BTRFS_I(inode)->root;
1886         struct btrfs_file_extent_item *fi;
1887         struct btrfs_path *path;
1888         struct extent_buffer *leaf;
1889         struct btrfs_key ins;
1890         int extent_inserted = 0;
1891         int ret;
1892
1893         path = btrfs_alloc_path();
1894         if (!path)
1895                 return -ENOMEM;
1896
1897         /*
1898          * we may be replacing one extent in the tree with another.
1899          * The new extent is pinned in the extent map, and we don't want
1900          * to drop it from the cache until it is completely in the btree.
1901          *
1902          * So, tell btrfs_drop_extents to leave this extent in the cache.
1903          * the caller is expected to unpin it and allow it to be merged
1904          * with the others.
1905          */
1906         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
1907                                    file_pos + num_bytes, NULL, 0,
1908                                    1, sizeof(*fi), &extent_inserted);
1909         if (ret)
1910                 goto out;
1911
1912         if (!extent_inserted) {
1913                 ins.objectid = btrfs_ino(inode);
1914                 ins.offset = file_pos;
1915                 ins.type = BTRFS_EXTENT_DATA_KEY;
1916
1917                 path->leave_spinning = 1;
1918                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
1919                                               sizeof(*fi));
1920                 if (ret)
1921                         goto out;
1922         }
1923         leaf = path->nodes[0];
1924         fi = btrfs_item_ptr(leaf, path->slots[0],
1925                             struct btrfs_file_extent_item);
1926         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1927         btrfs_set_file_extent_type(leaf, fi, extent_type);
1928         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1929         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1930         btrfs_set_file_extent_offset(leaf, fi, 0);
1931         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1932         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1933         btrfs_set_file_extent_compression(leaf, fi, compression);
1934         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1935         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1936
1937         btrfs_mark_buffer_dirty(leaf);
1938         btrfs_release_path(path);
1939
1940         inode_add_bytes(inode, num_bytes);
1941
1942         ins.objectid = disk_bytenr;
1943         ins.offset = disk_num_bytes;
1944         ins.type = BTRFS_EXTENT_ITEM_KEY;
1945         ret = btrfs_alloc_reserved_file_extent(trans, root,
1946                                         root->root_key.objectid,
1947                                         btrfs_ino(inode), file_pos, &ins);
1948 out:
1949         btrfs_free_path(path);
1950
1951         return ret;
1952 }
1953
1954 /* snapshot-aware defrag */
1955 struct sa_defrag_extent_backref {
1956         struct rb_node node;
1957         struct old_sa_defrag_extent *old;
1958         u64 root_id;
1959         u64 inum;
1960         u64 file_pos;
1961         u64 extent_offset;
1962         u64 num_bytes;
1963         u64 generation;
1964 };
1965
1966 struct old_sa_defrag_extent {
1967         struct list_head list;
1968         struct new_sa_defrag_extent *new;
1969
1970         u64 extent_offset;
1971         u64 bytenr;
1972         u64 offset;
1973         u64 len;
1974         int count;
1975 };
1976
1977 struct new_sa_defrag_extent {
1978         struct rb_root root;
1979         struct list_head head;
1980         struct btrfs_path *path;
1981         struct inode *inode;
1982         u64 file_pos;
1983         u64 len;
1984         u64 bytenr;
1985         u64 disk_len;
1986         u8 compress_type;
1987 };
1988
1989 static int backref_comp(struct sa_defrag_extent_backref *b1,
1990                         struct sa_defrag_extent_backref *b2)
1991 {
1992         if (b1->root_id < b2->root_id)
1993                 return -1;
1994         else if (b1->root_id > b2->root_id)
1995                 return 1;
1996
1997         if (b1->inum < b2->inum)
1998                 return -1;
1999         else if (b1->inum > b2->inum)
2000                 return 1;
2001
2002         if (b1->file_pos < b2->file_pos)
2003                 return -1;
2004         else if (b1->file_pos > b2->file_pos)
2005                 return 1;
2006
2007         /*
2008          * [------------------------------] ===> (a range of space)
2009          *     |<--->|   |<---->| =============> (fs/file tree A)
2010          * |<---------------------------->| ===> (fs/file tree B)
2011          *
2012          * A range of space can refer to two file extents in one tree while
2013          * refer to only one file extent in another tree.
2014          *
2015          * So we may process a disk offset more than one time(two extents in A)
2016          * and locate at the same extent(one extent in B), then insert two same
2017          * backrefs(both refer to the extent in B).
2018          */
2019         return 0;
2020 }
2021
2022 static void backref_insert(struct rb_root *root,
2023                            struct sa_defrag_extent_backref *backref)
2024 {
2025         struct rb_node **p = &root->rb_node;
2026         struct rb_node *parent = NULL;
2027         struct sa_defrag_extent_backref *entry;
2028         int ret;
2029
2030         while (*p) {
2031                 parent = *p;
2032                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2033
2034                 ret = backref_comp(backref, entry);
2035                 if (ret < 0)
2036                         p = &(*p)->rb_left;
2037                 else
2038                         p = &(*p)->rb_right;
2039         }
2040
2041         rb_link_node(&backref->node, parent, p);
2042         rb_insert_color(&backref->node, root);
2043 }
2044
2045 /*
2046  * Note the backref might has changed, and in this case we just return 0.
2047  */
2048 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2049                                        void *ctx)
2050 {
2051         struct btrfs_file_extent_item *extent;
2052         struct btrfs_fs_info *fs_info;
2053         struct old_sa_defrag_extent *old = ctx;
2054         struct new_sa_defrag_extent *new = old->new;
2055         struct btrfs_path *path = new->path;
2056         struct btrfs_key key;
2057         struct btrfs_root *root;
2058         struct sa_defrag_extent_backref *backref;
2059         struct extent_buffer *leaf;
2060         struct inode *inode = new->inode;
2061         int slot;
2062         int ret;
2063         u64 extent_offset;
2064         u64 num_bytes;
2065
2066         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2067             inum == btrfs_ino(inode))
2068                 return 0;
2069
2070         key.objectid = root_id;
2071         key.type = BTRFS_ROOT_ITEM_KEY;
2072         key.offset = (u64)-1;
2073
2074         fs_info = BTRFS_I(inode)->root->fs_info;
2075         root = btrfs_read_fs_root_no_name(fs_info, &key);
2076         if (IS_ERR(root)) {
2077                 if (PTR_ERR(root) == -ENOENT)
2078                         return 0;
2079                 WARN_ON(1);
2080                 pr_debug("inum=%llu, offset=%llu, root_id=%llu\n",
2081                          inum, offset, root_id);
2082                 return PTR_ERR(root);
2083         }
2084
2085         key.objectid = inum;
2086         key.type = BTRFS_EXTENT_DATA_KEY;
2087         if (offset > (u64)-1 << 32)
2088                 key.offset = 0;
2089         else
2090                 key.offset = offset;
2091
2092         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2093         if (WARN_ON(ret < 0))
2094                 return ret;
2095         ret = 0;
2096
2097         while (1) {
2098                 cond_resched();
2099
2100                 leaf = path->nodes[0];
2101                 slot = path->slots[0];
2102
2103                 if (slot >= btrfs_header_nritems(leaf)) {
2104                         ret = btrfs_next_leaf(root, path);
2105                         if (ret < 0) {
2106                                 goto out;
2107                         } else if (ret > 0) {
2108                                 ret = 0;
2109                                 goto out;
2110                         }
2111                         continue;
2112                 }
2113
2114                 path->slots[0]++;
2115
2116                 btrfs_item_key_to_cpu(leaf, &key, slot);
2117
2118                 if (key.objectid > inum)
2119                         goto out;
2120
2121                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2122                         continue;
2123
2124                 extent = btrfs_item_ptr(leaf, slot,
2125                                         struct btrfs_file_extent_item);
2126
2127                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2128                         continue;
2129
2130                 /*
2131                  * 'offset' refers to the exact key.offset,
2132                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2133                  * (key.offset - extent_offset).
2134                  */
2135                 if (key.offset != offset)
2136                         continue;
2137
2138                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2139                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2140
2141                 if (extent_offset >= old->extent_offset + old->offset +
2142                     old->len || extent_offset + num_bytes <=
2143                     old->extent_offset + old->offset)
2144                         continue;
2145                 break;
2146         }
2147
2148         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2149         if (!backref) {
2150                 ret = -ENOENT;
2151                 goto out;
2152         }
2153
2154         backref->root_id = root_id;
2155         backref->inum = inum;
2156         backref->file_pos = offset;
2157         backref->num_bytes = num_bytes;
2158         backref->extent_offset = extent_offset;
2159         backref->generation = btrfs_file_extent_generation(leaf, extent);
2160         backref->old = old;
2161         backref_insert(&new->root, backref);
2162         old->count++;
2163 out:
2164         btrfs_release_path(path);
2165         WARN_ON(ret);
2166         return ret;
2167 }
2168
2169 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2170                                    struct new_sa_defrag_extent *new)
2171 {
2172         struct btrfs_fs_info *fs_info = BTRFS_I(new->inode)->root->fs_info;
2173         struct old_sa_defrag_extent *old, *tmp;
2174         int ret;
2175
2176         new->path = path;
2177
2178         list_for_each_entry_safe(old, tmp, &new->head, list) {
2179                 ret = iterate_inodes_from_logical(old->bytenr +
2180                                                   old->extent_offset, fs_info,
2181                                                   path, record_one_backref,
2182                                                   old);
2183                 if (ret < 0 && ret != -ENOENT)
2184                         return false;
2185
2186                 /* no backref to be processed for this extent */
2187                 if (!old->count) {
2188                         list_del(&old->list);
2189                         kfree(old);
2190                 }
2191         }
2192
2193         if (list_empty(&new->head))
2194                 return false;
2195
2196         return true;
2197 }
2198
2199 static int relink_is_mergable(struct extent_buffer *leaf,
2200                               struct btrfs_file_extent_item *fi,
2201                               struct new_sa_defrag_extent *new)
2202 {
2203         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2204                 return 0;
2205
2206         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2207                 return 0;
2208
2209         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2210                 return 0;
2211
2212         if (btrfs_file_extent_encryption(leaf, fi) ||
2213             btrfs_file_extent_other_encoding(leaf, fi))
2214                 return 0;
2215
2216         return 1;
2217 }
2218
2219 /*
2220  * Note the backref might has changed, and in this case we just return 0.
2221  */
2222 static noinline int relink_extent_backref(struct btrfs_path *path,
2223                                  struct sa_defrag_extent_backref *prev,
2224                                  struct sa_defrag_extent_backref *backref)
2225 {
2226         struct btrfs_file_extent_item *extent;
2227         struct btrfs_file_extent_item *item;
2228         struct btrfs_ordered_extent *ordered;
2229         struct btrfs_trans_handle *trans;
2230         struct btrfs_fs_info *fs_info;
2231         struct btrfs_root *root;
2232         struct btrfs_key key;
2233         struct extent_buffer *leaf;
2234         struct old_sa_defrag_extent *old = backref->old;
2235         struct new_sa_defrag_extent *new = old->new;
2236         struct inode *src_inode = new->inode;
2237         struct inode *inode;
2238         struct extent_state *cached = NULL;
2239         int ret = 0;
2240         u64 start;
2241         u64 len;
2242         u64 lock_start;
2243         u64 lock_end;
2244         bool merge = false;
2245         int index;
2246
2247         if (prev && prev->root_id == backref->root_id &&
2248             prev->inum == backref->inum &&
2249             prev->file_pos + prev->num_bytes == backref->file_pos)
2250                 merge = true;
2251
2252         /* step 1: get root */
2253         key.objectid = backref->root_id;
2254         key.type = BTRFS_ROOT_ITEM_KEY;
2255         key.offset = (u64)-1;
2256
2257         fs_info = BTRFS_I(src_inode)->root->fs_info;
2258         index = srcu_read_lock(&fs_info->subvol_srcu);
2259
2260         root = btrfs_read_fs_root_no_name(fs_info, &key);
2261         if (IS_ERR(root)) {
2262                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2263                 if (PTR_ERR(root) == -ENOENT)
2264                         return 0;
2265                 return PTR_ERR(root);
2266         }
2267
2268         if (btrfs_root_readonly(root)) {
2269                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2270                 return 0;
2271         }
2272
2273         /* step 2: get inode */
2274         key.objectid = backref->inum;
2275         key.type = BTRFS_INODE_ITEM_KEY;
2276         key.offset = 0;
2277
2278         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2279         if (IS_ERR(inode)) {
2280                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2281                 return 0;
2282         }
2283
2284         srcu_read_unlock(&fs_info->subvol_srcu, index);
2285
2286         /* step 3: relink backref */
2287         lock_start = backref->file_pos;
2288         lock_end = backref->file_pos + backref->num_bytes - 1;
2289         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2290                          0, &cached);
2291
2292         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2293         if (ordered) {
2294                 btrfs_put_ordered_extent(ordered);
2295                 goto out_unlock;
2296         }
2297
2298         trans = btrfs_join_transaction(root);
2299         if (IS_ERR(trans)) {
2300                 ret = PTR_ERR(trans);
2301                 goto out_unlock;
2302         }
2303
2304         key.objectid = backref->inum;
2305         key.type = BTRFS_EXTENT_DATA_KEY;
2306         key.offset = backref->file_pos;
2307
2308         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2309         if (ret < 0) {
2310                 goto out_free_path;
2311         } else if (ret > 0) {
2312                 ret = 0;
2313                 goto out_free_path;
2314         }
2315
2316         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2317                                 struct btrfs_file_extent_item);
2318
2319         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2320             backref->generation)
2321                 goto out_free_path;
2322
2323         btrfs_release_path(path);
2324
2325         start = backref->file_pos;
2326         if (backref->extent_offset < old->extent_offset + old->offset)
2327                 start += old->extent_offset + old->offset -
2328                          backref->extent_offset;
2329
2330         len = min(backref->extent_offset + backref->num_bytes,
2331                   old->extent_offset + old->offset + old->len);
2332         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2333
2334         ret = btrfs_drop_extents(trans, root, inode, start,
2335                                  start + len, 1);
2336         if (ret)
2337                 goto out_free_path;
2338 again:
2339         key.objectid = btrfs_ino(inode);
2340         key.type = BTRFS_EXTENT_DATA_KEY;
2341         key.offset = start;
2342
2343         path->leave_spinning = 1;
2344         if (merge) {
2345                 struct btrfs_file_extent_item *fi;
2346                 u64 extent_len;
2347                 struct btrfs_key found_key;
2348
2349                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2350                 if (ret < 0)
2351                         goto out_free_path;
2352
2353                 path->slots[0]--;
2354                 leaf = path->nodes[0];
2355                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2356
2357                 fi = btrfs_item_ptr(leaf, path->slots[0],
2358                                     struct btrfs_file_extent_item);
2359                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2360
2361                 if (extent_len + found_key.offset == start &&
2362                     relink_is_mergable(leaf, fi, new)) {
2363                         btrfs_set_file_extent_num_bytes(leaf, fi,
2364                                                         extent_len + len);
2365                         btrfs_mark_buffer_dirty(leaf);
2366                         inode_add_bytes(inode, len);
2367
2368                         ret = 1;
2369                         goto out_free_path;
2370                 } else {
2371                         merge = false;
2372                         btrfs_release_path(path);
2373                         goto again;
2374                 }
2375         }
2376
2377         ret = btrfs_insert_empty_item(trans, root, path, &key,
2378                                         sizeof(*extent));
2379         if (ret) {
2380                 btrfs_abort_transaction(trans, root, ret);
2381                 goto out_free_path;
2382         }
2383
2384         leaf = path->nodes[0];
2385         item = btrfs_item_ptr(leaf, path->slots[0],
2386                                 struct btrfs_file_extent_item);
2387         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2388         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2389         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2390         btrfs_set_file_extent_num_bytes(leaf, item, len);
2391         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2392         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2393         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2394         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2395         btrfs_set_file_extent_encryption(leaf, item, 0);
2396         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2397
2398         btrfs_mark_buffer_dirty(leaf);
2399         inode_add_bytes(inode, len);
2400         btrfs_release_path(path);
2401
2402         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2403                         new->disk_len, 0,
2404                         backref->root_id, backref->inum,
2405                         new->file_pos, 0);      /* start - extent_offset */
2406         if (ret) {
2407                 btrfs_abort_transaction(trans, root, ret);
2408                 goto out_free_path;
2409         }
2410
2411         ret = 1;
2412 out_free_path:
2413         btrfs_release_path(path);
2414         path->leave_spinning = 0;
2415         btrfs_end_transaction(trans, root);
2416 out_unlock:
2417         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2418                              &cached, GFP_NOFS);
2419         iput(inode);
2420         return ret;
2421 }
2422
2423 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2424 {
2425         struct old_sa_defrag_extent *old, *tmp;
2426
2427         if (!new)
2428                 return;
2429
2430         list_for_each_entry_safe(old, tmp, &new->head, list) {
2431                 list_del(&old->list);
2432                 kfree(old);
2433         }
2434         kfree(new);
2435 }
2436
2437 static void relink_file_extents(struct new_sa_defrag_extent *new)
2438 {
2439         struct btrfs_path *path;
2440         struct sa_defrag_extent_backref *backref;
2441         struct sa_defrag_extent_backref *prev = NULL;
2442         struct inode *inode;
2443         struct btrfs_root *root;
2444         struct rb_node *node;
2445         int ret;
2446
2447         inode = new->inode;
2448         root = BTRFS_I(inode)->root;
2449
2450         path = btrfs_alloc_path();
2451         if (!path)
2452                 return;
2453
2454         if (!record_extent_backrefs(path, new)) {
2455                 btrfs_free_path(path);
2456                 goto out;
2457         }
2458         btrfs_release_path(path);
2459
2460         while (1) {
2461                 node = rb_first(&new->root);
2462                 if (!node)
2463                         break;
2464                 rb_erase(node, &new->root);
2465
2466                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2467
2468                 ret = relink_extent_backref(path, prev, backref);
2469                 WARN_ON(ret < 0);
2470
2471                 kfree(prev);
2472
2473                 if (ret == 1)
2474                         prev = backref;
2475                 else
2476                         prev = NULL;
2477                 cond_resched();
2478         }
2479         kfree(prev);
2480
2481         btrfs_free_path(path);
2482 out:
2483         free_sa_defrag_extent(new);
2484
2485         atomic_dec(&root->fs_info->defrag_running);
2486         wake_up(&root->fs_info->transaction_wait);
2487 }
2488
2489 static struct new_sa_defrag_extent *
2490 record_old_file_extents(struct inode *inode,
2491                         struct btrfs_ordered_extent *ordered)
2492 {
2493         struct btrfs_root *root = BTRFS_I(inode)->root;
2494         struct btrfs_path *path;
2495         struct btrfs_key key;
2496         struct old_sa_defrag_extent *old;
2497         struct new_sa_defrag_extent *new;
2498         int ret;
2499
2500         new = kmalloc(sizeof(*new), GFP_NOFS);
2501         if (!new)
2502                 return NULL;
2503
2504         new->inode = inode;
2505         new->file_pos = ordered->file_offset;
2506         new->len = ordered->len;
2507         new->bytenr = ordered->start;
2508         new->disk_len = ordered->disk_len;
2509         new->compress_type = ordered->compress_type;
2510         new->root = RB_ROOT;
2511         INIT_LIST_HEAD(&new->head);
2512
2513         path = btrfs_alloc_path();
2514         if (!path)
2515                 goto out_kfree;
2516
2517         key.objectid = btrfs_ino(inode);
2518         key.type = BTRFS_EXTENT_DATA_KEY;
2519         key.offset = new->file_pos;
2520
2521         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2522         if (ret < 0)
2523                 goto out_free_path;
2524         if (ret > 0 && path->slots[0] > 0)
2525                 path->slots[0]--;
2526
2527         /* find out all the old extents for the file range */
2528         while (1) {
2529                 struct btrfs_file_extent_item *extent;
2530                 struct extent_buffer *l;
2531                 int slot;
2532                 u64 num_bytes;
2533                 u64 offset;
2534                 u64 end;
2535                 u64 disk_bytenr;
2536                 u64 extent_offset;
2537
2538                 l = path->nodes[0];
2539                 slot = path->slots[0];
2540
2541                 if (slot >= btrfs_header_nritems(l)) {
2542                         ret = btrfs_next_leaf(root, path);
2543                         if (ret < 0)
2544                                 goto out_free_path;
2545                         else if (ret > 0)
2546                                 break;
2547                         continue;
2548                 }
2549
2550                 btrfs_item_key_to_cpu(l, &key, slot);
2551
2552                 if (key.objectid != btrfs_ino(inode))
2553                         break;
2554                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2555                         break;
2556                 if (key.offset >= new->file_pos + new->len)
2557                         break;
2558
2559                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2560
2561                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2562                 if (key.offset + num_bytes < new->file_pos)
2563                         goto next;
2564
2565                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2566                 if (!disk_bytenr)
2567                         goto next;
2568
2569                 extent_offset = btrfs_file_extent_offset(l, extent);
2570
2571                 old = kmalloc(sizeof(*old), GFP_NOFS);
2572                 if (!old)
2573                         goto out_free_path;
2574
2575                 offset = max(new->file_pos, key.offset);
2576                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2577
2578                 old->bytenr = disk_bytenr;
2579                 old->extent_offset = extent_offset;
2580                 old->offset = offset - key.offset;
2581                 old->len = end - offset;
2582                 old->new = new;
2583                 old->count = 0;
2584                 list_add_tail(&old->list, &new->head);
2585 next:
2586                 path->slots[0]++;
2587                 cond_resched();
2588         }
2589
2590         btrfs_free_path(path);
2591         atomic_inc(&root->fs_info->defrag_running);
2592
2593         return new;
2594
2595 out_free_path:
2596         btrfs_free_path(path);
2597 out_kfree:
2598         free_sa_defrag_extent(new);
2599         return NULL;
2600 }
2601
2602 /* as ordered data IO finishes, this gets called so we can finish
2603  * an ordered extent if the range of bytes in the file it covers are
2604  * fully written.
2605  */
2606 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2607 {
2608         struct inode *inode = ordered_extent->inode;
2609         struct btrfs_root *root = BTRFS_I(inode)->root;
2610         struct btrfs_trans_handle *trans = NULL;
2611         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2612         struct extent_state *cached_state = NULL;
2613         struct new_sa_defrag_extent *new = NULL;
2614         int compress_type = 0;
2615         int ret = 0;
2616         u64 logical_len = ordered_extent->len;
2617         bool nolock;
2618         bool truncated = false;
2619
2620         nolock = btrfs_is_free_space_inode(inode);
2621
2622         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2623                 ret = -EIO;
2624                 goto out;
2625         }
2626
2627         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2628                 truncated = true;
2629                 logical_len = ordered_extent->truncated_len;
2630                 /* Truncated the entire extent, don't bother adding */
2631                 if (!logical_len)
2632                         goto out;
2633         }
2634
2635         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2636                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2637                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2638                 if (nolock)
2639                         trans = btrfs_join_transaction_nolock(root);
2640                 else
2641                         trans = btrfs_join_transaction(root);
2642                 if (IS_ERR(trans)) {
2643                         ret = PTR_ERR(trans);
2644                         trans = NULL;
2645                         goto out;
2646                 }
2647                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2648                 ret = btrfs_update_inode_fallback(trans, root, inode);
2649                 if (ret) /* -ENOMEM or corruption */
2650                         btrfs_abort_transaction(trans, root, ret);
2651                 goto out;
2652         }
2653
2654         lock_extent_bits(io_tree, ordered_extent->file_offset,
2655                          ordered_extent->file_offset + ordered_extent->len - 1,
2656                          0, &cached_state);
2657
2658         ret = test_range_bit(io_tree, ordered_extent->file_offset,
2659                         ordered_extent->file_offset + ordered_extent->len - 1,
2660                         EXTENT_DEFRAG, 1, cached_state);
2661         if (ret) {
2662                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2663                 if (0 && last_snapshot >= BTRFS_I(inode)->generation)
2664                         /* the inode is shared */
2665                         new = record_old_file_extents(inode, ordered_extent);
2666
2667                 clear_extent_bit(io_tree, ordered_extent->file_offset,
2668                         ordered_extent->file_offset + ordered_extent->len - 1,
2669                         EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS);
2670         }
2671
2672         if (nolock)
2673                 trans = btrfs_join_transaction_nolock(root);
2674         else
2675                 trans = btrfs_join_transaction(root);
2676         if (IS_ERR(trans)) {
2677                 ret = PTR_ERR(trans);
2678                 trans = NULL;
2679                 goto out_unlock;
2680         }
2681         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2682
2683         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2684                 compress_type = ordered_extent->compress_type;
2685         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2686                 BUG_ON(compress_type);
2687                 ret = btrfs_mark_extent_written(trans, inode,
2688                                                 ordered_extent->file_offset,
2689                                                 ordered_extent->file_offset +
2690                                                 logical_len);
2691         } else {
2692                 BUG_ON(root == root->fs_info->tree_root);
2693                 ret = insert_reserved_file_extent(trans, inode,
2694                                                 ordered_extent->file_offset,
2695                                                 ordered_extent->start,
2696                                                 ordered_extent->disk_len,
2697                                                 logical_len, logical_len,
2698                                                 compress_type, 0, 0,
2699                                                 BTRFS_FILE_EXTENT_REG);
2700         }
2701         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2702                            ordered_extent->file_offset, ordered_extent->len,
2703                            trans->transid);
2704         if (ret < 0) {
2705                 btrfs_abort_transaction(trans, root, ret);
2706                 goto out_unlock;
2707         }
2708
2709         add_pending_csums(trans, inode, ordered_extent->file_offset,
2710                           &ordered_extent->list);
2711
2712         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2713         ret = btrfs_update_inode_fallback(trans, root, inode);
2714         if (ret) { /* -ENOMEM or corruption */
2715                 btrfs_abort_transaction(trans, root, ret);
2716                 goto out_unlock;
2717         }
2718         ret = 0;
2719 out_unlock:
2720         unlock_extent_cached(io_tree, ordered_extent->file_offset,
2721                              ordered_extent->file_offset +
2722                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
2723 out:
2724         if (root != root->fs_info->tree_root)
2725                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
2726         if (trans)
2727                 btrfs_end_transaction(trans, root);
2728
2729         if (ret || truncated) {
2730                 u64 start, end;
2731
2732                 if (truncated)
2733                         start = ordered_extent->file_offset + logical_len;
2734                 else
2735                         start = ordered_extent->file_offset;
2736                 end = ordered_extent->file_offset + ordered_extent->len - 1;
2737                 clear_extent_uptodate(io_tree, start, end, NULL, GFP_NOFS);
2738
2739                 /* Drop the cache for the part of the extent we didn't write. */
2740                 btrfs_drop_extent_cache(inode, start, end, 0);
2741
2742                 /*
2743                  * If the ordered extent had an IOERR or something else went
2744                  * wrong we need to return the space for this ordered extent
2745                  * back to the allocator.  We only free the extent in the
2746                  * truncated case if we didn't write out the extent at all.
2747                  */
2748                 if ((ret || !logical_len) &&
2749                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2750                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
2751                         btrfs_free_reserved_extent(root, ordered_extent->start,
2752                                                    ordered_extent->disk_len);
2753         }
2754
2755
2756         /*
2757          * This needs to be done to make sure anybody waiting knows we are done
2758          * updating everything for this ordered extent.
2759          */
2760         btrfs_remove_ordered_extent(inode, ordered_extent);
2761
2762         /* for snapshot-aware defrag */
2763         if (new) {
2764                 if (ret) {
2765                         free_sa_defrag_extent(new);
2766                         atomic_dec(&root->fs_info->defrag_running);
2767                 } else {
2768                         relink_file_extents(new);
2769                 }
2770         }
2771
2772         /* once for us */
2773         btrfs_put_ordered_extent(ordered_extent);
2774         /* once for the tree */
2775         btrfs_put_ordered_extent(ordered_extent);
2776
2777         return ret;
2778 }
2779
2780 static void finish_ordered_fn(struct btrfs_work *work)
2781 {
2782         struct btrfs_ordered_extent *ordered_extent;
2783         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
2784         btrfs_finish_ordered_io(ordered_extent);
2785 }
2786
2787 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
2788                                 struct extent_state *state, int uptodate)
2789 {
2790         struct inode *inode = page->mapping->host;
2791         struct btrfs_root *root = BTRFS_I(inode)->root;
2792         struct btrfs_ordered_extent *ordered_extent = NULL;
2793         struct btrfs_workqueue *workers;
2794
2795         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
2796
2797         ClearPagePrivate2(page);
2798         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
2799                                             end - start + 1, uptodate))
2800                 return 0;
2801
2802         btrfs_init_work(&ordered_extent->work, finish_ordered_fn, NULL, NULL);
2803
2804         if (btrfs_is_free_space_inode(inode))
2805                 workers = root->fs_info->endio_freespace_worker;
2806         else
2807                 workers = root->fs_info->endio_write_workers;
2808         btrfs_queue_work(workers, &ordered_extent->work);
2809
2810         return 0;
2811 }
2812
2813 /*
2814  * when reads are done, we need to check csums to verify the data is correct
2815  * if there's a match, we allow the bio to finish.  If not, the code in
2816  * extent_io.c will try to find good copies for us.
2817  */
2818 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
2819                                       u64 phy_offset, struct page *page,
2820                                       u64 start, u64 end, int mirror)
2821 {
2822         size_t offset = start - page_offset(page);
2823         struct inode *inode = page->mapping->host;
2824         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2825         char *kaddr;
2826         struct btrfs_root *root = BTRFS_I(inode)->root;
2827         u32 csum_expected;
2828         u32 csum = ~(u32)0;
2829         static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
2830                                       DEFAULT_RATELIMIT_BURST);
2831
2832         if (PageChecked(page)) {
2833                 ClearPageChecked(page);
2834                 goto good;
2835         }
2836
2837         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
2838                 goto good;
2839
2840         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
2841             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
2842                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
2843                                   GFP_NOFS);
2844                 return 0;
2845         }
2846
2847         phy_offset >>= inode->i_sb->s_blocksize_bits;
2848         csum_expected = *(((u32 *)io_bio->csum) + phy_offset);
2849
2850         kaddr = kmap_atomic(page);
2851         csum = btrfs_csum_data(kaddr + offset, csum,  end - start + 1);
2852         btrfs_csum_final(csum, (char *)&csum);
2853         if (csum != csum_expected)
2854                 goto zeroit;
2855
2856         kunmap_atomic(kaddr);
2857 good:
2858         return 0;
2859
2860 zeroit:
2861         if (__ratelimit(&_rs))
2862                 btrfs_info(root->fs_info, "csum failed ino %llu off %llu csum %u expected csum %u",
2863                         btrfs_ino(page->mapping->host), start, csum, csum_expected);
2864         memset(kaddr + offset, 1, end - start + 1);
2865         flush_dcache_page(page);
2866         kunmap_atomic(kaddr);
2867         if (csum_expected == 0)
2868                 return 0;
2869         return -EIO;
2870 }
2871
2872 struct delayed_iput {
2873         struct list_head list;
2874         struct inode *inode;
2875 };
2876
2877 /* JDM: If this is fs-wide, why can't we add a pointer to
2878  * btrfs_inode instead and avoid the allocation? */
2879 void btrfs_add_delayed_iput(struct inode *inode)
2880 {
2881         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2882         struct delayed_iput *delayed;
2883
2884         if (atomic_add_unless(&inode->i_count, -1, 1))
2885                 return;
2886
2887         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
2888         delayed->inode = inode;
2889
2890         spin_lock(&fs_info->delayed_iput_lock);
2891         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
2892         spin_unlock(&fs_info->delayed_iput_lock);
2893 }
2894
2895 void btrfs_run_delayed_iputs(struct btrfs_root *root)
2896 {
2897         LIST_HEAD(list);
2898         struct btrfs_fs_info *fs_info = root->fs_info;
2899         struct delayed_iput *delayed;
2900         int empty;
2901
2902         spin_lock(&fs_info->delayed_iput_lock);
2903         empty = list_empty(&fs_info->delayed_iputs);
2904         spin_unlock(&fs_info->delayed_iput_lock);
2905         if (empty)
2906                 return;
2907
2908         spin_lock(&fs_info->delayed_iput_lock);
2909         list_splice_init(&fs_info->delayed_iputs, &list);
2910         spin_unlock(&fs_info->delayed_iput_lock);
2911
2912         while (!list_empty(&list)) {
2913                 delayed = list_entry(list.next, struct delayed_iput, list);
2914                 list_del(&delayed->list);
2915                 iput(delayed->inode);
2916                 kfree(delayed);
2917         }
2918 }
2919
2920 /*
2921  * This is called in transaction commit time. If there are no orphan
2922  * files in the subvolume, it removes orphan item and frees block_rsv
2923  * structure.
2924  */
2925 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
2926                               struct btrfs_root *root)
2927 {
2928         struct btrfs_block_rsv *block_rsv;
2929         int ret;
2930
2931         if (atomic_read(&root->orphan_inodes) ||
2932             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
2933                 return;
2934
2935         spin_lock(&root->orphan_lock);
2936         if (atomic_read(&root->orphan_inodes)) {
2937                 spin_unlock(&root->orphan_lock);
2938                 return;
2939         }
2940
2941         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
2942                 spin_unlock(&root->orphan_lock);
2943                 return;
2944         }
2945
2946         block_rsv = root->orphan_block_rsv;
2947         root->orphan_block_rsv = NULL;
2948         spin_unlock(&root->orphan_lock);
2949
2950         if (root->orphan_item_inserted &&
2951             btrfs_root_refs(&root->root_item) > 0) {
2952                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
2953                                             root->root_key.objectid);
2954                 if (ret)
2955                         btrfs_abort_transaction(trans, root, ret);
2956                 else
2957                         root->orphan_item_inserted = 0;
2958         }
2959
2960         if (block_rsv) {
2961                 WARN_ON(block_rsv->size > 0);
2962                 btrfs_free_block_rsv(root, block_rsv);
2963         }
2964 }
2965
2966 /*
2967  * This creates an orphan entry for the given inode in case something goes
2968  * wrong in the middle of an unlink/truncate.
2969  *
2970  * NOTE: caller of this function should reserve 5 units of metadata for
2971  *       this function.
2972  */
2973 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
2974 {
2975         struct btrfs_root *root = BTRFS_I(inode)->root;
2976         struct btrfs_block_rsv *block_rsv = NULL;
2977         int reserve = 0;
2978         int insert = 0;
2979         int ret;
2980
2981         if (!root->orphan_block_rsv) {
2982                 block_rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
2983                 if (!block_rsv)
2984                         return -ENOMEM;
2985         }
2986
2987         spin_lock(&root->orphan_lock);
2988         if (!root->orphan_block_rsv) {
2989                 root->orphan_block_rsv = block_rsv;
2990         } else if (block_rsv) {
2991                 btrfs_free_block_rsv(root, block_rsv);
2992                 block_rsv = NULL;
2993         }
2994
2995         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
2996                               &BTRFS_I(inode)->runtime_flags)) {
2997 #if 0
2998                 /*
2999                  * For proper ENOSPC handling, we should do orphan
3000                  * cleanup when mounting. But this introduces backward
3001                  * compatibility issue.
3002                  */
3003                 if (!xchg(&root->orphan_item_inserted, 1))
3004                         insert = 2;
3005                 else
3006                         insert = 1;
3007 #endif
3008                 insert = 1;
3009                 atomic_inc(&root->orphan_inodes);
3010         }
3011
3012         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3013                               &BTRFS_I(inode)->runtime_flags))
3014                 reserve = 1;
3015         spin_unlock(&root->orphan_lock);
3016
3017         /* grab metadata reservation from transaction handle */
3018         if (reserve) {
3019                 ret = btrfs_orphan_reserve_metadata(trans, inode);
3020                 BUG_ON(ret); /* -ENOSPC in reservation; Logic error? JDM */
3021         }
3022
3023         /* insert an orphan item to track this unlinked/truncated file */
3024         if (insert >= 1) {
3025                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
3026                 if (ret) {
3027                         atomic_dec(&root->orphan_inodes);
3028                         if (reserve) {
3029                                 clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3030                                           &BTRFS_I(inode)->runtime_flags);
3031                                 btrfs_orphan_release_metadata(inode);
3032                         }
3033                         if (ret != -EEXIST) {
3034                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3035                                           &BTRFS_I(inode)->runtime_flags);
3036                                 btrfs_abort_transaction(trans, root, ret);
3037                                 return ret;
3038                         }
3039                 }
3040                 ret = 0;
3041         }
3042
3043         /* insert an orphan item to track subvolume contains orphan files */
3044         if (insert >= 2) {
3045                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
3046                                                root->root_key.objectid);
3047                 if (ret && ret != -EEXIST) {
3048                         btrfs_abort_transaction(trans, root, ret);
3049                         return ret;
3050                 }
3051         }
3052         return 0;
3053 }
3054
3055 /*
3056  * We have done the truncate/delete so we can go ahead and remove the orphan
3057  * item for this particular inode.
3058  */
3059 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3060                             struct inode *inode)
3061 {
3062         struct btrfs_root *root = BTRFS_I(inode)->root;
3063         int delete_item = 0;
3064         int release_rsv = 0;
3065         int ret = 0;
3066
3067         spin_lock(&root->orphan_lock);
3068         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3069                                &BTRFS_I(inode)->runtime_flags))
3070                 delete_item = 1;
3071
3072         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3073                                &BTRFS_I(inode)->runtime_flags))
3074                 release_rsv = 1;
3075         spin_unlock(&root->orphan_lock);
3076
3077         if (delete_item) {
3078                 atomic_dec(&root->orphan_inodes);
3079                 if (trans)
3080                         ret = btrfs_del_orphan_item(trans, root,
3081                                                     btrfs_ino(inode));
3082         }
3083
3084         if (release_rsv)
3085                 btrfs_orphan_release_metadata(inode);
3086
3087         return ret;
3088 }
3089
3090 /*
3091  * this cleans up any orphans that may be left on the list from the last use
3092  * of this root.
3093  */
3094 int btrfs_orphan_cleanup(struct btrfs_root *root)
3095 {
3096         struct btrfs_path *path;
3097         struct extent_buffer *leaf;
3098         struct btrfs_key key, found_key;
3099         struct btrfs_trans_handle *trans;
3100         struct inode *inode;
3101         u64 last_objectid = 0;
3102         int ret = 0, nr_unlink = 0, nr_truncate = 0;
3103
3104         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3105                 return 0;
3106
3107         path = btrfs_alloc_path();
3108         if (!path) {
3109                 ret = -ENOMEM;
3110                 goto out;
3111         }
3112         path->reada = -1;
3113
3114         key.objectid = BTRFS_ORPHAN_OBJECTID;
3115         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
3116         key.offset = (u64)-1;
3117
3118         while (1) {
3119                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3120                 if (ret < 0)
3121                         goto out;
3122
3123                 /*
3124                  * if ret == 0 means we found what we were searching for, which
3125                  * is weird, but possible, so only screw with path if we didn't
3126                  * find the key and see if we have stuff that matches
3127                  */
3128                 if (ret > 0) {
3129                         ret = 0;
3130                         if (path->slots[0] == 0)
3131                                 break;
3132                         path->slots[0]--;
3133                 }
3134
3135                 /* pull out the item */
3136                 leaf = path->nodes[0];
3137                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3138
3139                 /* make sure the item matches what we want */
3140                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3141                         break;
3142                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
3143                         break;
3144
3145                 /* release the path since we're done with it */
3146                 btrfs_release_path(path);
3147
3148                 /*
3149                  * this is where we are basically btrfs_lookup, without the
3150                  * crossing root thing.  we store the inode number in the
3151                  * offset of the orphan item.
3152                  */
3153
3154                 if (found_key.offset == last_objectid) {
3155                         btrfs_err(root->fs_info,
3156                                 "Error removing orphan entry, stopping orphan cleanup");
3157                         ret = -EINVAL;
3158                         goto out;
3159                 }
3160
3161                 last_objectid = found_key.offset;
3162
3163                 found_key.objectid = found_key.offset;
3164                 found_key.type = BTRFS_INODE_ITEM_KEY;
3165                 found_key.offset = 0;
3166                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
3167                 ret = PTR_ERR_OR_ZERO(inode);
3168                 if (ret && ret != -ESTALE)
3169                         goto out;
3170
3171                 if (ret == -ESTALE && root == root->fs_info->tree_root) {
3172                         struct btrfs_root *dead_root;
3173                         struct btrfs_fs_info *fs_info = root->fs_info;
3174                         int is_dead_root = 0;
3175
3176                         /*
3177                          * this is an orphan in the tree root. Currently these
3178                          * could come from 2 sources:
3179                          *  a) a snapshot deletion in progress
3180                          *  b) a free space cache inode
3181                          * We need to distinguish those two, as the snapshot
3182                          * orphan must not get deleted.
3183                          * find_dead_roots already ran before us, so if this
3184                          * is a snapshot deletion, we should find the root
3185                          * in the dead_roots list
3186                          */
3187                         spin_lock(&fs_info->trans_lock);
3188                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3189                                             root_list) {
3190                                 if (dead_root->root_key.objectid ==
3191                                     found_key.objectid) {
3192                                         is_dead_root = 1;
3193                                         break;
3194                                 }
3195                         }
3196                         spin_unlock(&fs_info->trans_lock);
3197                         if (is_dead_root) {
3198                                 /* prevent this orphan from being found again */
3199                                 key.offset = found_key.objectid - 1;
3200                                 continue;
3201                         }
3202                 }
3203                 /*
3204                  * Inode is already gone but the orphan item is still there,
3205                  * kill the orphan item.
3206                  */
3207                 if (ret == -ESTALE) {
3208                         trans = btrfs_start_transaction(root, 1);
3209                         if (IS_ERR(trans)) {
3210                                 ret = PTR_ERR(trans);
3211                                 goto out;
3212                         }
3213                         btrfs_debug(root->fs_info, "auto deleting %Lu",
3214                                 found_key.objectid);
3215                         ret = btrfs_del_orphan_item(trans, root,
3216                                                     found_key.objectid);
3217                         btrfs_end_transaction(trans, root);
3218                         if (ret)
3219                                 goto out;
3220                         continue;
3221                 }
3222
3223                 /*
3224                  * add this inode to the orphan list so btrfs_orphan_del does
3225                  * the proper thing when we hit it
3226                  */
3227                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3228                         &BTRFS_I(inode)->runtime_flags);
3229                 atomic_inc(&root->orphan_inodes);
3230
3231                 /* if we have links, this was a truncate, lets do that */
3232                 if (inode->i_nlink) {
3233                         if (WARN_ON(!S_ISREG(inode->i_mode))) {
3234                                 iput(inode);
3235                                 continue;
3236                         }
3237                         nr_truncate++;
3238
3239                         /* 1 for the orphan item deletion. */
3240                         trans = btrfs_start_transaction(root, 1);
3241                         if (IS_ERR(trans)) {
3242                                 iput(inode);
3243                                 ret = PTR_ERR(trans);
3244                                 goto out;
3245                         }
3246                         ret = btrfs_orphan_add(trans, inode);
3247                         btrfs_end_transaction(trans, root);
3248                         if (ret) {
3249                                 iput(inode);
3250                                 goto out;
3251                         }
3252
3253                         ret = btrfs_truncate(inode);
3254                         if (ret)
3255                                 btrfs_orphan_del(NULL, inode);
3256                 } else {
3257                         nr_unlink++;
3258                 }
3259
3260                 /* this will do delete_inode and everything for us */
3261                 iput(inode);
3262                 if (ret)
3263                         goto out;
3264         }
3265         /* release the path since we're done with it */
3266         btrfs_release_path(path);
3267
3268         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3269
3270         if (root->orphan_block_rsv)
3271                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
3272                                         (u64)-1);
3273
3274         if (root->orphan_block_rsv || root->orphan_item_inserted) {
3275                 trans = btrfs_join_transaction(root);
3276                 if (!IS_ERR(trans))
3277                         btrfs_end_transaction(trans, root);
3278         }
3279
3280         if (nr_unlink)
3281                 btrfs_debug(root->fs_info, "unlinked %d orphans", nr_unlink);
3282         if (nr_truncate)
3283                 btrfs_debug(root->fs_info, "truncated %d orphans", nr_truncate);
3284
3285 out:
3286         if (ret)
3287                 btrfs_crit(root->fs_info,
3288                         "could not do orphan cleanup %d", ret);
3289         btrfs_free_path(path);
3290         return ret;
3291 }
3292
3293 /*
3294  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3295  * don't find any xattrs, we know there can't be any acls.
3296  *
3297  * slot is the slot the inode is in, objectid is the objectid of the inode
3298  */
3299 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3300                                           int slot, u64 objectid,
3301                                           int *first_xattr_slot)
3302 {
3303         u32 nritems = btrfs_header_nritems(leaf);
3304         struct btrfs_key found_key;
3305         static u64 xattr_access = 0;
3306         static u64 xattr_default = 0;
3307         int scanned = 0;
3308
3309         if (!xattr_access) {
3310                 xattr_access = btrfs_name_hash(POSIX_ACL_XATTR_ACCESS,
3311                                         strlen(POSIX_ACL_XATTR_ACCESS));
3312                 xattr_default = btrfs_name_hash(POSIX_ACL_XATTR_DEFAULT,
3313                                         strlen(POSIX_ACL_XATTR_DEFAULT));
3314         }
3315
3316         slot++;
3317         *first_xattr_slot = -1;
3318         while (slot < nritems) {
3319                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3320
3321                 /* we found a different objectid, there must not be acls */
3322                 if (found_key.objectid != objectid)
3323                         return 0;
3324
3325                 /* we found an xattr, assume we've got an acl */
3326                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3327                         if (*first_xattr_slot == -1)
3328                                 *first_xattr_slot = slot;
3329                         if (found_key.offset == xattr_access ||
3330                             found_key.offset == xattr_default)
3331                                 return 1;
3332                 }
3333
3334                 /*
3335                  * we found a key greater than an xattr key, there can't
3336                  * be any acls later on
3337                  */
3338                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3339                         return 0;
3340
3341                 slot++;
3342                 scanned++;
3343
3344                 /*
3345                  * it goes inode, inode backrefs, xattrs, extents,
3346                  * so if there are a ton of hard links to an inode there can
3347                  * be a lot of backrefs.  Don't waste time searching too hard,
3348                  * this is just an optimization
3349                  */
3350                 if (scanned >= 8)
3351                         break;
3352         }
3353         /* we hit the end of the leaf before we found an xattr or
3354          * something larger than an xattr.  We have to assume the inode
3355          * has acls
3356          */
3357         if (*first_xattr_slot == -1)
3358                 *first_xattr_slot = slot;
3359         return 1;
3360 }
3361
3362 /*
3363  * read an inode from the btree into the in-memory inode
3364  */
3365 static void btrfs_read_locked_inode(struct inode *inode)
3366 {
3367         struct btrfs_path *path;
3368         struct extent_buffer *leaf;
3369         struct btrfs_inode_item *inode_item;
3370         struct btrfs_timespec *tspec;
3371         struct btrfs_root *root = BTRFS_I(inode)->root;
3372         struct btrfs_key location;
3373         unsigned long ptr;
3374         int maybe_acls;
3375         u32 rdev;
3376         int ret;
3377         bool filled = false;
3378         int first_xattr_slot;
3379
3380         ret = btrfs_fill_inode(inode, &rdev);
3381         if (!ret)
3382                 filled = true;
3383
3384         path = btrfs_alloc_path();
3385         if (!path)
3386                 goto make_bad;
3387
3388         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3389
3390         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3391         if (ret)
3392                 goto make_bad;
3393
3394         leaf = path->nodes[0];
3395
3396         if (filled)
3397                 goto cache_index;
3398
3399         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3400                                     struct btrfs_inode_item);
3401         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3402         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3403         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3404         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3405         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
3406
3407         tspec = btrfs_inode_atime(inode_item);
3408         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3409         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3410
3411         tspec = btrfs_inode_mtime(inode_item);
3412         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3413         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3414
3415         tspec = btrfs_inode_ctime(inode_item);
3416         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3417         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3418
3419         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3420         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3421         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3422
3423         /*
3424          * If we were modified in the current generation and evicted from memory
3425          * and then re-read we need to do a full sync since we don't have any
3426          * idea about which extents were modified before we were evicted from
3427          * cache.
3428          */
3429         if (BTRFS_I(inode)->last_trans == root->fs_info->generation)
3430                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3431                         &BTRFS_I(inode)->runtime_flags);
3432
3433         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
3434         inode->i_generation = BTRFS_I(inode)->generation;
3435         inode->i_rdev = 0;
3436         rdev = btrfs_inode_rdev(leaf, inode_item);
3437
3438         BTRFS_I(inode)->index_cnt = (u64)-1;
3439         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3440
3441 cache_index:
3442         path->slots[0]++;
3443         if (inode->i_nlink != 1 ||
3444             path->slots[0] >= btrfs_header_nritems(leaf))
3445                 goto cache_acl;
3446
3447         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3448         if (location.objectid != btrfs_ino(inode))
3449                 goto cache_acl;
3450
3451         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3452         if (location.type == BTRFS_INODE_REF_KEY) {
3453                 struct btrfs_inode_ref *ref;
3454
3455                 ref = (struct btrfs_inode_ref *)ptr;
3456                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3457         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3458                 struct btrfs_inode_extref *extref;
3459
3460                 extref = (struct btrfs_inode_extref *)ptr;
3461                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3462                                                                      extref);
3463         }
3464 cache_acl:
3465         /*
3466          * try to precache a NULL acl entry for files that don't have
3467          * any xattrs or acls
3468          */
3469         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3470                                            btrfs_ino(inode), &first_xattr_slot);
3471         if (first_xattr_slot != -1) {
3472                 path->slots[0] = first_xattr_slot;
3473                 ret = btrfs_load_inode_props(inode, path);
3474                 if (ret)
3475                         btrfs_err(root->fs_info,
3476                                   "error loading props for ino %llu (root %llu): %d\n",
3477                                   btrfs_ino(inode),
3478                                   root->root_key.objectid, ret);
3479         }
3480         btrfs_free_path(path);
3481
3482         if (!maybe_acls)
3483                 cache_no_acl(inode);
3484
3485         switch (inode->i_mode & S_IFMT) {
3486         case S_IFREG:
3487                 inode->i_mapping->a_ops = &btrfs_aops;
3488                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3489                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3490                 inode->i_fop = &btrfs_file_operations;
3491                 inode->i_op = &btrfs_file_inode_operations;
3492                 break;
3493         case S_IFDIR:
3494                 inode->i_fop = &btrfs_dir_file_operations;
3495                 if (root == root->fs_info->tree_root)
3496                         inode->i_op = &btrfs_dir_ro_inode_operations;
3497                 else
3498                         inode->i_op = &btrfs_dir_inode_operations;
3499                 break;
3500         case S_IFLNK:
3501                 inode->i_op = &btrfs_symlink_inode_operations;
3502                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3503                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3504                 break;
3505         default:
3506                 inode->i_op = &btrfs_special_inode_operations;
3507                 init_special_inode(inode, inode->i_mode, rdev);
3508                 break;
3509         }
3510
3511         btrfs_update_iflags(inode);
3512         return;
3513
3514 make_bad:
3515         btrfs_free_path(path);
3516         make_bad_inode(inode);
3517 }
3518
3519 /*
3520  * given a leaf and an inode, copy the inode fields into the leaf
3521  */
3522 static void fill_inode_item(struct btrfs_trans_handle *trans,
3523                             struct extent_buffer *leaf,
3524                             struct btrfs_inode_item *item,
3525                             struct inode *inode)
3526 {
3527         struct btrfs_map_token token;
3528
3529         btrfs_init_map_token(&token);
3530
3531         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3532         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3533         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3534                                    &token);
3535         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3536         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3537
3538         btrfs_set_token_timespec_sec(leaf, btrfs_inode_atime(item),
3539                                      inode->i_atime.tv_sec, &token);
3540         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_atime(item),
3541                                       inode->i_atime.tv_nsec, &token);
3542
3543         btrfs_set_token_timespec_sec(leaf, btrfs_inode_mtime(item),
3544                                      inode->i_mtime.tv_sec, &token);
3545         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_mtime(item),
3546                                       inode->i_mtime.tv_nsec, &token);
3547
3548         btrfs_set_token_timespec_sec(leaf, btrfs_inode_ctime(item),
3549                                      inode->i_ctime.tv_sec, &token);
3550         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_ctime(item),
3551                                       inode->i_ctime.tv_nsec, &token);
3552
3553         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3554                                      &token);
3555         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3556                                          &token);
3557         btrfs_set_token_inode_sequence(leaf, item, inode->i_version, &token);
3558         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3559         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3560         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3561         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3562 }
3563
3564 /*
3565  * copy everything in the in-memory inode into the btree.
3566  */
3567 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3568                                 struct btrfs_root *root, struct inode *inode)
3569 {
3570         struct btrfs_inode_item *inode_item;
3571         struct btrfs_path *path;
3572         struct extent_buffer *leaf;
3573         int ret;
3574
3575         path = btrfs_alloc_path();
3576         if (!path)
3577                 return -ENOMEM;
3578
3579         path->leave_spinning = 1;
3580         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3581                                  1);
3582         if (ret) {
3583                 if (ret > 0)
3584                         ret = -ENOENT;
3585                 goto failed;
3586         }
3587
3588         leaf = path->nodes[0];
3589         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3590                                     struct btrfs_inode_item);
3591
3592         fill_inode_item(trans, leaf, inode_item, inode);
3593         btrfs_mark_buffer_dirty(leaf);
3594         btrfs_set_inode_last_trans(trans, inode);
3595         ret = 0;
3596 failed:
3597         btrfs_free_path(path);
3598         return ret;
3599 }
3600
3601 /*
3602  * copy everything in the in-memory inode into the btree.
3603  */
3604 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3605                                 struct btrfs_root *root, struct inode *inode)
3606 {
3607         int ret;
3608
3609         /*
3610          * If the inode is a free space inode, we can deadlock during commit
3611          * if we put it into the delayed code.
3612          *
3613          * The data relocation inode should also be directly updated
3614          * without delay
3615          */
3616         if (!btrfs_is_free_space_inode(inode)
3617             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID) {
3618                 btrfs_update_root_times(trans, root);
3619
3620                 ret = btrfs_delayed_update_inode(trans, root, inode);
3621                 if (!ret)
3622                         btrfs_set_inode_last_trans(trans, inode);
3623                 return ret;
3624         }
3625
3626         return btrfs_update_inode_item(trans, root, inode);
3627 }
3628
3629 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3630                                          struct btrfs_root *root,
3631                                          struct inode *inode)
3632 {
3633         int ret;
3634
3635         ret = btrfs_update_inode(trans, root, inode);
3636         if (ret == -ENOSPC)
3637                 return btrfs_update_inode_item(trans, root, inode);
3638         return ret;
3639 }
3640
3641 /*
3642  * unlink helper that gets used here in inode.c and in the tree logging
3643  * recovery code.  It remove a link in a directory with a given name, and
3644  * also drops the back refs in the inode to the directory
3645  */
3646 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3647                                 struct btrfs_root *root,
3648                                 struct inode *dir, struct inode *inode,
3649                                 const char *name, int name_len)
3650 {
3651         struct btrfs_path *path;
3652         int ret = 0;
3653         struct extent_buffer *leaf;
3654         struct btrfs_dir_item *di;
3655         struct btrfs_key key;
3656         u64 index;
3657         u64 ino = btrfs_ino(inode);
3658         u64 dir_ino = btrfs_ino(dir);
3659
3660         path = btrfs_alloc_path();
3661         if (!path) {
3662                 ret = -ENOMEM;
3663                 goto out;
3664         }
3665
3666         path->leave_spinning = 1;
3667         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3668                                     name, name_len, -1);
3669         if (IS_ERR(di)) {
3670                 ret = PTR_ERR(di);
3671                 goto err;
3672         }
3673         if (!di) {
3674                 ret = -ENOENT;
3675                 goto err;
3676         }
3677         leaf = path->nodes[0];
3678         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3679         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3680         if (ret)
3681                 goto err;
3682         btrfs_release_path(path);
3683
3684         /*
3685          * If we don't have dir index, we have to get it by looking up
3686          * the inode ref, since we get the inode ref, remove it directly,
3687          * it is unnecessary to do delayed deletion.
3688          *
3689          * But if we have dir index, needn't search inode ref to get it.
3690          * Since the inode ref is close to the inode item, it is better
3691          * that we delay to delete it, and just do this deletion when
3692          * we update the inode item.
3693          */
3694         if (BTRFS_I(inode)->dir_index) {
3695                 ret = btrfs_delayed_delete_inode_ref(inode);
3696                 if (!ret) {
3697                         index = BTRFS_I(inode)->dir_index;
3698                         goto skip_backref;
3699                 }
3700         }
3701
3702         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3703                                   dir_ino, &index);
3704         if (ret) {
3705                 btrfs_info(root->fs_info,
3706                         "failed to delete reference to %.*s, inode %llu parent %llu",
3707                         name_len, name, ino, dir_ino);
3708                 btrfs_abort_transaction(trans, root, ret);
3709                 goto err;
3710         }
3711 skip_backref:
3712         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3713         if (ret) {
3714                 btrfs_abort_transaction(trans, root, ret);
3715                 goto err;
3716         }
3717
3718         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
3719                                          inode, dir_ino);
3720         if (ret != 0 && ret != -ENOENT) {
3721                 btrfs_abort_transaction(trans, root, ret);
3722                 goto err;
3723         }
3724
3725         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
3726                                            dir, index);
3727         if (ret == -ENOENT)
3728                 ret = 0;
3729         else if (ret)
3730                 btrfs_abort_transaction(trans, root, ret);
3731 err:
3732         btrfs_free_path(path);
3733         if (ret)
3734                 goto out;
3735
3736         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3737         inode_inc_iversion(inode);
3738         inode_inc_iversion(dir);
3739         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3740         ret = btrfs_update_inode(trans, root, dir);
3741 out:
3742         return ret;
3743 }
3744
3745 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3746                        struct btrfs_root *root,
3747                        struct inode *dir, struct inode *inode,
3748                        const char *name, int name_len)
3749 {
3750         int ret;
3751         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
3752         if (!ret) {
3753                 drop_nlink(inode);
3754                 ret = btrfs_update_inode(trans, root, inode);
3755         }
3756         return ret;
3757 }
3758
3759 /*
3760  * helper to start transaction for unlink and rmdir.
3761  *
3762  * unlink and rmdir are special in btrfs, they do not always free space, so
3763  * if we cannot make our reservations the normal way try and see if there is
3764  * plenty of slack room in the global reserve to migrate, otherwise we cannot
3765  * allow the unlink to occur.
3766  */
3767 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
3768 {
3769         struct btrfs_trans_handle *trans;
3770         struct btrfs_root *root = BTRFS_I(dir)->root;
3771         int ret;
3772
3773         /*
3774          * 1 for the possible orphan item
3775          * 1 for the dir item
3776          * 1 for the dir index
3777          * 1 for the inode ref
3778          * 1 for the inode
3779          */
3780         trans = btrfs_start_transaction(root, 5);
3781         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
3782                 return trans;
3783
3784         if (PTR_ERR(trans) == -ENOSPC) {
3785                 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
3786
3787                 trans = btrfs_start_transaction(root, 0);
3788                 if (IS_ERR(trans))
3789                         return trans;
3790                 ret = btrfs_cond_migrate_bytes(root->fs_info,
3791                                                &root->fs_info->trans_block_rsv,
3792                                                num_bytes, 5);
3793                 if (ret) {
3794                         btrfs_end_transaction(trans, root);
3795                         return ERR_PTR(ret);
3796                 }
3797                 trans->block_rsv = &root->fs_info->trans_block_rsv;
3798                 trans->bytes_reserved = num_bytes;
3799         }
3800         return trans;
3801 }
3802
3803 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
3804 {
3805         struct btrfs_root *root = BTRFS_I(dir)->root;
3806         struct btrfs_trans_handle *trans;
3807         struct inode *inode = dentry->d_inode;
3808         int ret;
3809
3810         trans = __unlink_start_trans(dir);
3811         if (IS_ERR(trans))
3812                 return PTR_ERR(trans);
3813
3814         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
3815
3816         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3817                                  dentry->d_name.name, dentry->d_name.len);
3818         if (ret)
3819                 goto out;
3820
3821         if (inode->i_nlink == 0) {
3822                 ret = btrfs_orphan_add(trans, inode);
3823                 if (ret)
3824                         goto out;
3825         }
3826
3827 out:
3828         btrfs_end_transaction(trans, root);
3829         btrfs_btree_balance_dirty(root);
3830         return ret;
3831 }
3832
3833 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
3834                         struct btrfs_root *root,
3835                         struct inode *dir, u64 objectid,
3836                         const char *name, int name_len)
3837 {
3838         struct btrfs_path *path;
3839         struct extent_buffer *leaf;
3840         struct btrfs_dir_item *di;
3841         struct btrfs_key key;
3842         u64 index;
3843         int ret;
3844         u64 dir_ino = btrfs_ino(dir);
3845
3846         path = btrfs_alloc_path();
3847         if (!path)
3848                 return -ENOMEM;
3849
3850         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3851                                    name, name_len, -1);
3852         if (IS_ERR_OR_NULL(di)) {
3853                 if (!di)
3854                         ret = -ENOENT;
3855                 else
3856                         ret = PTR_ERR(di);
3857                 goto out;
3858         }
3859
3860         leaf = path->nodes[0];
3861         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3862         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3863         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3864         if (ret) {
3865                 btrfs_abort_transaction(trans, root, ret);
3866                 goto out;
3867         }
3868         btrfs_release_path(path);
3869
3870         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3871                                  objectid, root->root_key.objectid,
3872                                  dir_ino, &index, name, name_len);
3873         if (ret < 0) {
3874                 if (ret != -ENOENT) {
3875                         btrfs_abort_transaction(trans, root, ret);
3876                         goto out;
3877                 }
3878                 di = btrfs_search_dir_index_item(root, path, dir_ino,
3879                                                  name, name_len);
3880                 if (IS_ERR_OR_NULL(di)) {
3881                         if (!di)
3882                                 ret = -ENOENT;
3883                         else
3884                                 ret = PTR_ERR(di);
3885                         btrfs_abort_transaction(trans, root, ret);
3886                         goto out;
3887                 }
3888
3889                 leaf = path->nodes[0];
3890                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3891                 btrfs_release_path(path);
3892                 index = key.offset;
3893         }
3894         btrfs_release_path(path);
3895
3896         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3897         if (ret) {
3898                 btrfs_abort_transaction(trans, root, ret);
3899                 goto out;
3900         }
3901
3902         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3903         inode_inc_iversion(dir);
3904         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3905         ret = btrfs_update_inode_fallback(trans, root, dir);
3906         if (ret)
3907                 btrfs_abort_transaction(trans, root, ret);
3908 out:
3909         btrfs_free_path(path);
3910         return ret;
3911 }
3912
3913 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
3914 {
3915         struct inode *inode = dentry->d_inode;
3916         int err = 0;
3917         struct btrfs_root *root = BTRFS_I(dir)->root;
3918         struct btrfs_trans_handle *trans;
3919
3920         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
3921                 return -ENOTEMPTY;
3922         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
3923                 return -EPERM;
3924
3925         trans = __unlink_start_trans(dir);
3926         if (IS_ERR(trans))
3927                 return PTR_ERR(trans);
3928
3929         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
3930                 err = btrfs_unlink_subvol(trans, root, dir,
3931                                           BTRFS_I(inode)->location.objectid,
3932                                           dentry->d_name.name,
3933                                           dentry->d_name.len);
3934                 goto out;
3935         }
3936
3937         err = btrfs_orphan_add(trans, inode);
3938         if (err)
3939                 goto out;
3940
3941         /* now the directory is empty */
3942         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3943                                  dentry->d_name.name, dentry->d_name.len);
3944         if (!err)
3945                 btrfs_i_size_write(inode, 0);
3946 out:
3947         btrfs_end_transaction(trans, root);
3948         btrfs_btree_balance_dirty(root);
3949
3950         return err;
3951 }
3952
3953 /*
3954  * this can truncate away extent items, csum items and directory items.
3955  * It starts at a high offset and removes keys until it can't find
3956  * any higher than new_size
3957  *
3958  * csum items that cross the new i_size are truncated to the new size
3959  * as well.
3960  *
3961  * min_type is the minimum key type to truncate down to.  If set to 0, this
3962  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3963  */
3964 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
3965                                struct btrfs_root *root,
3966                                struct inode *inode,
3967                                u64 new_size, u32 min_type)
3968 {
3969         struct btrfs_path *path;
3970         struct extent_buffer *leaf;
3971         struct btrfs_file_extent_item *fi;
3972         struct btrfs_key key;
3973         struct btrfs_key found_key;
3974         u64 extent_start = 0;
3975         u64 extent_num_bytes = 0;
3976         u64 extent_offset = 0;
3977         u64 item_end = 0;
3978         u64 last_size = (u64)-1;
3979         u32 found_type = (u8)-1;
3980         int found_extent;
3981         int del_item;
3982         int pending_del_nr = 0;
3983         int pending_del_slot = 0;
3984         int extent_type = -1;
3985         int ret;
3986         int err = 0;
3987         u64 ino = btrfs_ino(inode);
3988
3989         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
3990
3991         path = btrfs_alloc_path();
3992         if (!path)
3993                 return -ENOMEM;
3994         path->reada = -1;
3995
3996         /*
3997          * We want to drop from the next block forward in case this new size is
3998          * not block aligned since we will be keeping the last block of the
3999          * extent just the way it is.
4000          */
4001         if (root->ref_cows || root == root->fs_info->tree_root)
4002                 btrfs_drop_extent_cache(inode, ALIGN(new_size,
4003                                         root->sectorsize), (u64)-1, 0);
4004
4005         /*
4006          * This function is also used to drop the items in the log tree before
4007          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4008          * it is used to drop the loged items. So we shouldn't kill the delayed
4009          * items.
4010          */
4011         if (min_type == 0 && root == BTRFS_I(inode)->root)
4012                 btrfs_kill_delayed_inode_items(inode);
4013
4014         key.objectid = ino;
4015         key.offset = (u64)-1;
4016         key.type = (u8)-1;
4017
4018 search_again:
4019         path->leave_spinning = 1;
4020         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4021         if (ret < 0) {
4022                 err = ret;
4023                 goto out;
4024         }
4025
4026         if (ret > 0) {
4027                 /* there are no items in the tree for us to truncate, we're
4028                  * done
4029                  */
4030                 if (path->slots[0] == 0)
4031                         goto out;
4032                 path->slots[0]--;
4033         }
4034
4035         while (1) {
4036                 fi = NULL;
4037                 leaf = path->nodes[0];
4038                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4039                 found_type = btrfs_key_type(&found_key);
4040
4041                 if (found_key.objectid != ino)
4042                         break;
4043
4044                 if (found_type < min_type)
4045                         break;
4046
4047                 item_end = found_key.offset;
4048                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4049                         fi = btrfs_item_ptr(leaf, path->slots[0],
4050                                             struct btrfs_file_extent_item);
4051                         extent_type = btrfs_file_extent_type(leaf, fi);
4052                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4053                                 item_end +=
4054                                     btrfs_file_extent_num_bytes(leaf, fi);
4055                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4056                                 item_end += btrfs_file_extent_inline_len(leaf,
4057                                                          path->slots[0], fi);
4058                         }
4059                         item_end--;
4060                 }
4061                 if (found_type > min_type) {
4062                         del_item = 1;
4063                 } else {
4064                         if (item_end < new_size)
4065                                 break;
4066                         if (found_key.offset >= new_size)
4067                                 del_item = 1;
4068                         else
4069                                 del_item = 0;
4070                 }
4071                 found_extent = 0;
4072                 /* FIXME, shrink the extent if the ref count is only 1 */
4073                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4074                         goto delete;
4075
4076                 if (del_item)
4077                         last_size = found_key.offset;
4078                 else
4079                         last_size = new_size;
4080
4081                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4082                         u64 num_dec;
4083                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4084                         if (!del_item) {
4085                                 u64 orig_num_bytes =
4086                                         btrfs_file_extent_num_bytes(leaf, fi);
4087                                 extent_num_bytes = ALIGN(new_size -
4088                                                 found_key.offset,
4089                                                 root->sectorsize);
4090                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4091                                                          extent_num_bytes);
4092                                 num_dec = (orig_num_bytes -
4093                                            extent_num_bytes);
4094                                 if (root->ref_cows && extent_start != 0)
4095                                         inode_sub_bytes(inode, num_dec);
4096                                 btrfs_mark_buffer_dirty(leaf);
4097                         } else {
4098                                 extent_num_bytes =
4099                                         btrfs_file_extent_disk_num_bytes(leaf,
4100                                                                          fi);
4101                                 extent_offset = found_key.offset -
4102                                         btrfs_file_extent_offset(leaf, fi);
4103
4104                                 /* FIXME blocksize != 4096 */
4105                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4106                                 if (extent_start != 0) {
4107                                         found_extent = 1;
4108                                         if (root->ref_cows)
4109                                                 inode_sub_bytes(inode, num_dec);
4110                                 }
4111                         }
4112                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4113                         /*
4114                          * we can't truncate inline items that have had
4115                          * special encodings
4116                          */
4117                         if (!del_item &&
4118                             btrfs_file_extent_compression(leaf, fi) == 0 &&
4119                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4120                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
4121                                 u32 size = new_size - found_key.offset;
4122
4123                                 if (root->ref_cows) {
4124                                         inode_sub_bytes(inode, item_end + 1 -
4125                                                         new_size);
4126                                 }
4127
4128                                 /*
4129                                  * update the ram bytes to properly reflect
4130                                  * the new size of our item
4131                                  */
4132                                 btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4133                                 size =
4134                                     btrfs_file_extent_calc_inline_size(size);
4135                                 btrfs_truncate_item(root, path, size, 1);
4136                         } else if (root->ref_cows) {
4137                                 inode_sub_bytes(inode, item_end + 1 -
4138                                                 found_key.offset);
4139                         }
4140                 }
4141 delete:
4142                 if (del_item) {
4143                         if (!pending_del_nr) {
4144                                 /* no pending yet, add ourselves */
4145                                 pending_del_slot = path->slots[0];
4146                                 pending_del_nr = 1;
4147                         } else if (pending_del_nr &&
4148                                    path->slots[0] + 1 == pending_del_slot) {
4149                                 /* hop on the pending chunk */
4150                                 pending_del_nr++;
4151                                 pending_del_slot = path->slots[0];
4152                         } else {
4153                                 BUG();
4154                         }
4155                 } else {
4156                         break;
4157                 }
4158                 if (found_extent && (root->ref_cows ||
4159                                      root == root->fs_info->tree_root)) {
4160                         btrfs_set_path_blocking(path);
4161                         ret = btrfs_free_extent(trans, root, extent_start,
4162                                                 extent_num_bytes, 0,
4163                                                 btrfs_header_owner(leaf),
4164                                                 ino, extent_offset, 0);
4165                         BUG_ON(ret);
4166                 }
4167
4168                 if (found_type == BTRFS_INODE_ITEM_KEY)
4169                         break;
4170
4171                 if (path->slots[0] == 0 ||
4172                     path->slots[0] != pending_del_slot) {
4173                         if (pending_del_nr) {
4174                                 ret = btrfs_del_items(trans, root, path,
4175                                                 pending_del_slot,
4176                                                 pending_del_nr);
4177                                 if (ret) {
4178                                         btrfs_abort_transaction(trans,
4179                                                                 root, ret);
4180                                         goto error;
4181                                 }
4182                                 pending_del_nr = 0;
4183                         }
4184                         btrfs_release_path(path);
4185                         goto search_again;
4186                 } else {
4187                         path->slots[0]--;
4188                 }
4189         }
4190 out:
4191         if (pending_del_nr) {
4192                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
4193                                       pending_del_nr);
4194                 if (ret)
4195                         btrfs_abort_transaction(trans, root, ret);
4196         }
4197 error:
4198         if (last_size != (u64)-1)
4199                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4200         btrfs_free_path(path);
4201         return err;
4202 }
4203
4204 /*
4205  * btrfs_truncate_page - read, zero a chunk and write a page
4206  * @inode - inode that we're zeroing
4207  * @from - the offset to start zeroing
4208  * @len - the length to zero, 0 to zero the entire range respective to the
4209  *      offset
4210  * @front - zero up to the offset instead of from the offset on
4211  *
4212  * This will find the page for the "from" offset and cow the page and zero the
4213  * part we want to zero.  This is used with truncate and hole punching.
4214  */
4215 int btrfs_truncate_page(struct inode *inode, loff_t from, loff_t len,
4216                         int front)
4217 {
4218         struct address_space *mapping = inode->i_mapping;
4219         struct btrfs_root *root = BTRFS_I(inode)->root;
4220         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4221         struct btrfs_ordered_extent *ordered;
4222         struct extent_state *cached_state = NULL;
4223         char *kaddr;
4224         u32 blocksize = root->sectorsize;
4225         pgoff_t index = from >> PAGE_CACHE_SHIFT;
4226         unsigned offset = from & (PAGE_CACHE_SIZE-1);
4227         struct page *page;
4228         gfp_t mask = btrfs_alloc_write_mask(mapping);
4229         int ret = 0;
4230         u64 page_start;
4231         u64 page_end;
4232
4233         if ((offset & (blocksize - 1)) == 0 &&
4234             (!len || ((len & (blocksize - 1)) == 0)))
4235                 goto out;
4236         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
4237         if (ret)
4238                 goto out;
4239
4240 again:
4241         page = find_or_create_page(mapping, index, mask);
4242         if (!page) {
4243                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4244                 ret = -ENOMEM;
4245                 goto out;
4246         }
4247
4248         page_start = page_offset(page);
4249         page_end = page_start + PAGE_CACHE_SIZE - 1;
4250
4251         if (!PageUptodate(page)) {
4252                 ret = btrfs_readpage(NULL, page);
4253                 lock_page(page);
4254                 if (page->mapping != mapping) {
4255                         unlock_page(page);
4256                         page_cache_release(page);
4257                         goto again;
4258                 }
4259                 if (!PageUptodate(page)) {
4260                         ret = -EIO;
4261                         goto out_unlock;
4262                 }
4263         }
4264         wait_on_page_writeback(page);
4265
4266         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
4267         set_page_extent_mapped(page);
4268
4269         ordered = btrfs_lookup_ordered_extent(inode, page_start);
4270         if (ordered) {
4271                 unlock_extent_cached(io_tree, page_start, page_end,
4272                                      &cached_state, GFP_NOFS);
4273                 unlock_page(page);
4274                 page_cache_release(page);
4275                 btrfs_start_ordered_extent(inode, ordered, 1);
4276                 btrfs_put_ordered_extent(ordered);
4277                 goto again;
4278         }
4279
4280         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
4281                           EXTENT_DIRTY | EXTENT_DELALLOC |
4282                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4283                           0, 0, &cached_state, GFP_NOFS);
4284
4285         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
4286                                         &cached_state);
4287         if (ret) {
4288                 unlock_extent_cached(io_tree, page_start, page_end,
4289                                      &cached_state, GFP_NOFS);
4290                 goto out_unlock;
4291         }
4292
4293         if (offset != PAGE_CACHE_SIZE) {
4294                 if (!len)
4295                         len = PAGE_CACHE_SIZE - offset;
4296                 kaddr = kmap(page);
4297                 if (front)
4298                         memset(kaddr, 0, offset);
4299                 else
4300                         memset(kaddr + offset, 0, len);
4301                 flush_dcache_page(page);
4302                 kunmap(page);
4303         }
4304         ClearPageChecked(page);
4305         set_page_dirty(page);
4306         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
4307                              GFP_NOFS);
4308
4309 out_unlock:
4310         if (ret)
4311                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4312         unlock_page(page);
4313         page_cache_release(page);
4314 out:
4315         return ret;
4316 }
4317
4318 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4319                              u64 offset, u64 len)
4320 {
4321         struct btrfs_trans_handle *trans;
4322         int ret;
4323
4324         /*
4325          * Still need to make sure the inode looks like it's been updated so
4326          * that any holes get logged if we fsync.
4327          */
4328         if (btrfs_fs_incompat(root->fs_info, NO_HOLES)) {
4329                 BTRFS_I(inode)->last_trans = root->fs_info->generation;
4330                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4331                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4332                 return 0;
4333         }
4334
4335         /*
4336          * 1 - for the one we're dropping
4337          * 1 - for the one we're adding
4338          * 1 - for updating the inode.
4339          */
4340         trans = btrfs_start_transaction(root, 3);
4341         if (IS_ERR(trans))
4342                 return PTR_ERR(trans);
4343
4344         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4345         if (ret) {
4346                 btrfs_abort_transaction(trans, root, ret);
4347                 btrfs_end_transaction(trans, root);
4348                 return ret;
4349         }
4350
4351         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
4352                                        0, 0, len, 0, len, 0, 0, 0);
4353         if (ret)
4354                 btrfs_abort_transaction(trans, root, ret);
4355         else
4356                 btrfs_update_inode(trans, root, inode);
4357         btrfs_end_transaction(trans, root);
4358         return ret;
4359 }
4360
4361 /*
4362  * This function puts in dummy file extents for the area we're creating a hole
4363  * for.  So if we are truncating this file to a larger size we need to insert
4364  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4365  * the range between oldsize and size
4366  */
4367 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4368 {
4369         struct btrfs_root *root = BTRFS_I(inode)->root;
4370         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4371         struct extent_map *em = NULL;
4372         struct extent_state *cached_state = NULL;
4373         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4374         u64 hole_start = ALIGN(oldsize, root->sectorsize);
4375         u64 block_end = ALIGN(size, root->sectorsize);
4376         u64 last_byte;
4377         u64 cur_offset;
4378         u64 hole_size;
4379         int err = 0;
4380
4381         /*
4382          * If our size started in the middle of a page we need to zero out the
4383          * rest of the page before we expand the i_size, otherwise we could
4384          * expose stale data.
4385          */
4386         err = btrfs_truncate_page(inode, oldsize, 0, 0);
4387         if (err)
4388                 return err;
4389
4390         if (size <= hole_start)
4391                 return 0;
4392
4393         while (1) {
4394                 struct btrfs_ordered_extent *ordered;
4395
4396                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
4397                                  &cached_state);
4398                 ordered = btrfs_lookup_ordered_range(inode, hole_start,
4399                                                      block_end - hole_start);
4400                 if (!ordered)
4401                         break;
4402                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
4403                                      &cached_state, GFP_NOFS);
4404                 btrfs_start_ordered_extent(inode, ordered, 1);
4405                 btrfs_put_ordered_extent(ordered);
4406         }
4407
4408         cur_offset = hole_start;
4409         while (1) {
4410                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
4411                                 block_end - cur_offset, 0);
4412                 if (IS_ERR(em)) {
4413                         err = PTR_ERR(em);
4414                         em = NULL;
4415                         break;
4416                 }
4417                 last_byte = min(extent_map_end(em), block_end);
4418                 last_byte = ALIGN(last_byte , root->sectorsize);
4419                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4420                         struct extent_map *hole_em;
4421                         hole_size = last_byte - cur_offset;
4422
4423                         err = maybe_insert_hole(root, inode, cur_offset,
4424                                                 hole_size);
4425                         if (err)
4426                                 break;
4427                         btrfs_drop_extent_cache(inode, cur_offset,
4428                                                 cur_offset + hole_size - 1, 0);
4429                         hole_em = alloc_extent_map();
4430                         if (!hole_em) {
4431                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4432                                         &BTRFS_I(inode)->runtime_flags);
4433                                 goto next;
4434                         }
4435                         hole_em->start = cur_offset;
4436                         hole_em->len = hole_size;
4437                         hole_em->orig_start = cur_offset;
4438
4439                         hole_em->block_start = EXTENT_MAP_HOLE;
4440                         hole_em->block_len = 0;
4441                         hole_em->orig_block_len = 0;
4442                         hole_em->ram_bytes = hole_size;
4443                         hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
4444                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4445                         hole_em->generation = root->fs_info->generation;
4446
4447                         while (1) {
4448                                 write_lock(&em_tree->lock);
4449                                 err = add_extent_mapping(em_tree, hole_em, 1);
4450                                 write_unlock(&em_tree->lock);
4451                                 if (err != -EEXIST)
4452                                         break;
4453                                 btrfs_drop_extent_cache(inode, cur_offset,
4454                                                         cur_offset +
4455                                                         hole_size - 1, 0);
4456                         }
4457                         free_extent_map(hole_em);
4458                 }
4459 next:
4460                 free_extent_map(em);
4461                 em = NULL;
4462                 cur_offset = last_byte;
4463                 if (cur_offset >= block_end)
4464                         break;
4465         }
4466         free_extent_map(em);
4467         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
4468                              GFP_NOFS);
4469         return err;
4470 }
4471
4472 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4473 {
4474         struct btrfs_root *root = BTRFS_I(inode)->root;
4475         struct btrfs_trans_handle *trans;
4476         loff_t oldsize = i_size_read(inode);
4477         loff_t newsize = attr->ia_size;
4478         int mask = attr->ia_valid;
4479         int ret;
4480
4481         /*
4482          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4483          * special case where we need to update the times despite not having
4484          * these flags set.  For all other operations the VFS set these flags
4485          * explicitly if it wants a timestamp update.
4486          */
4487         if (newsize != oldsize) {
4488                 inode_inc_iversion(inode);
4489                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
4490                         inode->i_ctime = inode->i_mtime =
4491                                 current_fs_time(inode->i_sb);
4492         }
4493
4494         if (newsize > oldsize) {
4495                 truncate_pagecache(inode, newsize);
4496                 ret = btrfs_cont_expand(inode, oldsize, newsize);
4497                 if (ret)
4498                         return ret;
4499
4500                 trans = btrfs_start_transaction(root, 1);
4501                 if (IS_ERR(trans))
4502                         return PTR_ERR(trans);
4503
4504                 i_size_write(inode, newsize);
4505                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
4506                 ret = btrfs_update_inode(trans, root, inode);
4507                 btrfs_end_transaction(trans, root);
4508         } else {
4509
4510                 /*
4511                  * We're truncating a file that used to have good data down to
4512                  * zero. Make sure it gets into the ordered flush list so that
4513                  * any new writes get down to disk quickly.
4514                  */
4515                 if (newsize == 0)
4516                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
4517                                 &BTRFS_I(inode)->runtime_flags);
4518
4519                 /*
4520                  * 1 for the orphan item we're going to add
4521                  * 1 for the orphan item deletion.
4522                  */
4523                 trans = btrfs_start_transaction(root, 2);
4524                 if (IS_ERR(trans))
4525                         return PTR_ERR(trans);
4526
4527                 /*
4528                  * We need to do this in case we fail at _any_ point during the
4529                  * actual truncate.  Once we do the truncate_setsize we could
4530                  * invalidate pages which forces any outstanding ordered io to
4531                  * be instantly completed which will give us extents that need
4532                  * to be truncated.  If we fail to get an orphan inode down we
4533                  * could have left over extents that were never meant to live,
4534                  * so we need to garuntee from this point on that everything
4535                  * will be consistent.
4536                  */
4537                 ret = btrfs_orphan_add(trans, inode);
4538                 btrfs_end_transaction(trans, root);
4539                 if (ret)
4540                         return ret;
4541
4542                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
4543                 truncate_setsize(inode, newsize);
4544
4545                 /* Disable nonlocked read DIO to avoid the end less truncate */
4546                 btrfs_inode_block_unlocked_dio(inode);
4547                 inode_dio_wait(inode);
4548                 btrfs_inode_resume_unlocked_dio(inode);
4549
4550                 ret = btrfs_truncate(inode);
4551                 if (ret && inode->i_nlink) {
4552                         int err;
4553
4554                         /*
4555                          * failed to truncate, disk_i_size is only adjusted down
4556                          * as we remove extents, so it should represent the true
4557                          * size of the inode, so reset the in memory size and
4558                          * delete our orphan entry.
4559                          */
4560                         trans = btrfs_join_transaction(root);
4561                         if (IS_ERR(trans)) {
4562                                 btrfs_orphan_del(NULL, inode);
4563                                 return ret;
4564                         }
4565                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
4566                         err = btrfs_orphan_del(trans, inode);
4567                         if (err)
4568                                 btrfs_abort_transaction(trans, root, err);
4569                         btrfs_end_transaction(trans, root);
4570                 }
4571         }
4572
4573         return ret;
4574 }
4575
4576 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
4577 {
4578         struct inode *inode = dentry->d_inode;
4579         struct btrfs_root *root = BTRFS_I(inode)->root;
4580         int err;
4581
4582         if (btrfs_root_readonly(root))
4583                 return -EROFS;
4584
4585         err = inode_change_ok(inode, attr);
4586         if (err)
4587                 return err;
4588
4589         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
4590                 err = btrfs_setsize(inode, attr);
4591                 if (err)
4592                         return err;
4593         }
4594
4595         if (attr->ia_valid) {
4596                 setattr_copy(inode, attr);
4597                 inode_inc_iversion(inode);
4598                 err = btrfs_dirty_inode(inode);
4599
4600                 if (!err && attr->ia_valid & ATTR_MODE)
4601                         err = posix_acl_chmod(inode, inode->i_mode);
4602         }
4603
4604         return err;
4605 }
4606
4607 /*
4608  * While truncating the inode pages during eviction, we get the VFS calling
4609  * btrfs_invalidatepage() against each page of the inode. This is slow because
4610  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
4611  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
4612  * extent_state structures over and over, wasting lots of time.
4613  *
4614  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
4615  * those expensive operations on a per page basis and do only the ordered io
4616  * finishing, while we release here the extent_map and extent_state structures,
4617  * without the excessive merging and splitting.
4618  */
4619 static void evict_inode_truncate_pages(struct inode *inode)
4620 {
4621         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4622         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
4623         struct rb_node *node;
4624
4625         ASSERT(inode->i_state & I_FREEING);
4626         truncate_inode_pages_final(&inode->i_data);
4627
4628         write_lock(&map_tree->lock);
4629         while (!RB_EMPTY_ROOT(&map_tree->map)) {
4630                 struct extent_map *em;
4631
4632                 node = rb_first(&map_tree->map);
4633                 em = rb_entry(node, struct extent_map, rb_node);
4634                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
4635                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
4636                 remove_extent_mapping(map_tree, em);
4637                 free_extent_map(em);
4638         }
4639         write_unlock(&map_tree->lock);
4640
4641         spin_lock(&io_tree->lock);
4642         while (!RB_EMPTY_ROOT(&io_tree->state)) {
4643                 struct extent_state *state;
4644                 struct extent_state *cached_state = NULL;
4645
4646                 node = rb_first(&io_tree->state);
4647                 state = rb_entry(node, struct extent_state, rb_node);
4648                 atomic_inc(&state->refs);
4649                 spin_unlock(&io_tree->lock);
4650
4651                 lock_extent_bits(io_tree, state->start, state->end,
4652                                  0, &cached_state);
4653                 clear_extent_bit(io_tree, state->start, state->end,
4654                                  EXTENT_LOCKED | EXTENT_DIRTY |
4655                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
4656                                  EXTENT_DEFRAG, 1, 1,
4657                                  &cached_state, GFP_NOFS);
4658                 free_extent_state(state);
4659
4660                 spin_lock(&io_tree->lock);
4661         }
4662         spin_unlock(&io_tree->lock);
4663 }
4664
4665 void btrfs_evict_inode(struct inode *inode)
4666 {
4667         struct btrfs_trans_handle *trans;
4668         struct btrfs_root *root = BTRFS_I(inode)->root;
4669         struct btrfs_block_rsv *rsv, *global_rsv;
4670         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
4671         int ret;
4672
4673         trace_btrfs_inode_evict(inode);
4674
4675         evict_inode_truncate_pages(inode);
4676
4677         if (inode->i_nlink &&
4678             ((btrfs_root_refs(&root->root_item) != 0 &&
4679               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
4680              btrfs_is_free_space_inode(inode)))
4681                 goto no_delete;
4682
4683         if (is_bad_inode(inode)) {
4684                 btrfs_orphan_del(NULL, inode);
4685                 goto no_delete;
4686         }
4687         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
4688         btrfs_wait_ordered_range(inode, 0, (u64)-1);
4689
4690         if (root->fs_info->log_root_recovering) {
4691                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
4692                                  &BTRFS_I(inode)->runtime_flags));
4693                 goto no_delete;
4694         }
4695
4696         if (inode->i_nlink > 0) {
4697                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
4698                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
4699                 goto no_delete;
4700         }
4701
4702         ret = btrfs_commit_inode_delayed_inode(inode);
4703         if (ret) {
4704                 btrfs_orphan_del(NULL, inode);
4705                 goto no_delete;
4706         }
4707
4708         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
4709         if (!rsv) {
4710                 btrfs_orphan_del(NULL, inode);
4711                 goto no_delete;
4712         }
4713         rsv->size = min_size;
4714         rsv->failfast = 1;
4715         global_rsv = &root->fs_info->global_block_rsv;
4716
4717         btrfs_i_size_write(inode, 0);
4718
4719         /*
4720          * This is a bit simpler than btrfs_truncate since we've already
4721          * reserved our space for our orphan item in the unlink, so we just
4722          * need to reserve some slack space in case we add bytes and update
4723          * inode item when doing the truncate.
4724          */
4725         while (1) {
4726                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
4727                                              BTRFS_RESERVE_FLUSH_LIMIT);
4728
4729                 /*
4730                  * Try and steal from the global reserve since we will
4731                  * likely not use this space anyway, we want to try as
4732                  * hard as possible to get this to work.
4733                  */
4734                 if (ret)
4735                         ret = btrfs_block_rsv_migrate(global_rsv, rsv, min_size);
4736
4737                 if (ret) {
4738                         btrfs_warn(root->fs_info,
4739                                 "Could not get space for a delete, will truncate on mount %d",
4740                                 ret);
4741                         btrfs_orphan_del(NULL, inode);
4742                         btrfs_free_block_rsv(root, rsv);
4743                         goto no_delete;
4744                 }
4745
4746                 trans = btrfs_join_transaction(root);
4747                 if (IS_ERR(trans)) {
4748                         btrfs_orphan_del(NULL, inode);
4749                         btrfs_free_block_rsv(root, rsv);
4750                         goto no_delete;
4751                 }
4752
4753                 trans->block_rsv = rsv;
4754
4755                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
4756                 if (ret != -ENOSPC)
4757                         break;
4758
4759                 trans->block_rsv = &root->fs_info->trans_block_rsv;
4760                 btrfs_end_transaction(trans, root);
4761                 trans = NULL;
4762                 btrfs_btree_balance_dirty(root);
4763         }
4764
4765         btrfs_free_block_rsv(root, rsv);
4766
4767         /*
4768          * Errors here aren't a big deal, it just means we leave orphan items
4769          * in the tree.  They will be cleaned up on the next mount.
4770          */
4771         if (ret == 0) {
4772                 trans->block_rsv = root->orphan_block_rsv;
4773                 btrfs_orphan_del(trans, inode);
4774         } else {
4775                 btrfs_orphan_del(NULL, inode);
4776         }
4777
4778         trans->block_rsv = &root->fs_info->trans_block_rsv;
4779         if (!(root == root->fs_info->tree_root ||
4780               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
4781                 btrfs_return_ino(root, btrfs_ino(inode));
4782
4783         btrfs_end_transaction(trans, root);
4784         btrfs_btree_balance_dirty(root);
4785 no_delete:
4786         btrfs_remove_delayed_node(inode);
4787         clear_inode(inode);
4788         return;
4789 }
4790
4791 /*
4792  * this returns the key found in the dir entry in the location pointer.
4793  * If no dir entries were found, location->objectid is 0.
4794  */
4795 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
4796                                struct btrfs_key *location)
4797 {
4798         const char *name = dentry->d_name.name;
4799         int namelen = dentry->d_name.len;
4800         struct btrfs_dir_item *di;
4801         struct btrfs_path *path;
4802         struct btrfs_root *root = BTRFS_I(dir)->root;
4803         int ret = 0;
4804
4805         path = btrfs_alloc_path();
4806         if (!path)
4807                 return -ENOMEM;
4808
4809         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
4810                                     namelen, 0);
4811         if (IS_ERR(di))
4812                 ret = PTR_ERR(di);
4813
4814         if (IS_ERR_OR_NULL(di))
4815                 goto out_err;
4816
4817         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
4818 out:
4819         btrfs_free_path(path);
4820         return ret;
4821 out_err:
4822         location->objectid = 0;
4823         goto out;
4824 }
4825
4826 /*
4827  * when we hit a tree root in a directory, the btrfs part of the inode
4828  * needs to be changed to reflect the root directory of the tree root.  This
4829  * is kind of like crossing a mount point.
4830  */
4831 static int fixup_tree_root_location(struct btrfs_root *root,
4832                                     struct inode *dir,
4833                                     struct dentry *dentry,
4834                                     struct btrfs_key *location,
4835                                     struct btrfs_root **sub_root)
4836 {
4837         struct btrfs_path *path;
4838         struct btrfs_root *new_root;
4839         struct btrfs_root_ref *ref;
4840         struct extent_buffer *leaf;
4841         int ret;
4842         int err = 0;
4843
4844         path = btrfs_alloc_path();
4845         if (!path) {
4846                 err = -ENOMEM;
4847                 goto out;
4848         }
4849
4850         err = -ENOENT;
4851         ret = btrfs_find_item(root->fs_info->tree_root, path,
4852                                 BTRFS_I(dir)->root->root_key.objectid,
4853                                 location->objectid, BTRFS_ROOT_REF_KEY, NULL);
4854         if (ret) {
4855                 if (ret < 0)
4856                         err = ret;
4857                 goto out;
4858         }
4859
4860         leaf = path->nodes[0];
4861         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
4862         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
4863             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
4864                 goto out;
4865
4866         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
4867                                    (unsigned long)(ref + 1),
4868                                    dentry->d_name.len);
4869         if (ret)
4870                 goto out;
4871
4872         btrfs_release_path(path);
4873
4874         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
4875         if (IS_ERR(new_root)) {
4876                 err = PTR_ERR(new_root);
4877                 goto out;
4878         }
4879
4880         *sub_root = new_root;
4881         location->objectid = btrfs_root_dirid(&new_root->root_item);
4882         location->type = BTRFS_INODE_ITEM_KEY;
4883         location->offset = 0;
4884         err = 0;
4885 out:
4886         btrfs_free_path(path);
4887         return err;
4888 }
4889
4890 static void inode_tree_add(struct inode *inode)
4891 {
4892         struct btrfs_root *root = BTRFS_I(inode)->root;
4893         struct btrfs_inode *entry;
4894         struct rb_node **p;
4895         struct rb_node *parent;
4896         struct rb_node *new = &BTRFS_I(inode)->rb_node;
4897         u64 ino = btrfs_ino(inode);
4898
4899         if (inode_unhashed(inode))
4900                 return;
4901         parent = NULL;
4902         spin_lock(&root->inode_lock);
4903         p = &root->inode_tree.rb_node;
4904         while (*p) {
4905                 parent = *p;
4906                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
4907
4908                 if (ino < btrfs_ino(&entry->vfs_inode))
4909                         p = &parent->rb_left;
4910                 else if (ino > btrfs_ino(&entry->vfs_inode))
4911                         p = &parent->rb_right;
4912                 else {
4913                         WARN_ON(!(entry->vfs_inode.i_state &
4914                                   (I_WILL_FREE | I_FREEING)));
4915                         rb_replace_node(parent, new, &root->inode_tree);
4916                         RB_CLEAR_NODE(parent);
4917                         spin_unlock(&root->inode_lock);
4918                         return;
4919                 }
4920         }
4921         rb_link_node(new, parent, p);
4922         rb_insert_color(new, &root->inode_tree);
4923         spin_unlock(&root->inode_lock);
4924 }
4925
4926 static void inode_tree_del(struct inode *inode)
4927 {
4928         struct btrfs_root *root = BTRFS_I(inode)->root;
4929         int empty = 0;
4930
4931         spin_lock(&root->inode_lock);
4932         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
4933                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
4934                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
4935                 empty = RB_EMPTY_ROOT(&root->inode_tree);
4936         }
4937         spin_unlock(&root->inode_lock);
4938
4939         if (empty && btrfs_root_refs(&root->root_item) == 0) {
4940                 synchronize_srcu(&root->fs_info->subvol_srcu);
4941                 spin_lock(&root->inode_lock);
4942                 empty = RB_EMPTY_ROOT(&root->inode_tree);
4943                 spin_unlock(&root->inode_lock);
4944                 if (empty)
4945                         btrfs_add_dead_root(root);
4946         }
4947 }
4948
4949 void btrfs_invalidate_inodes(struct btrfs_root *root)
4950 {
4951         struct rb_node *node;
4952         struct rb_node *prev;
4953         struct btrfs_inode *entry;
4954         struct inode *inode;
4955         u64 objectid = 0;
4956
4957         if (!test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
4958                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
4959
4960         spin_lock(&root->inode_lock);
4961 again:
4962         node = root->inode_tree.rb_node;
4963         prev = NULL;
4964         while (node) {
4965                 prev = node;
4966                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4967
4968                 if (objectid < btrfs_ino(&entry->vfs_inode))
4969                         node = node->rb_left;
4970                 else if (objectid > btrfs_ino(&entry->vfs_inode))
4971                         node = node->rb_right;
4972                 else
4973                         break;
4974         }
4975         if (!node) {
4976                 while (prev) {
4977                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
4978                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
4979                                 node = prev;
4980                                 break;
4981                         }
4982                         prev = rb_next(prev);
4983                 }
4984         }
4985         while (node) {
4986                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4987                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
4988                 inode = igrab(&entry->vfs_inode);
4989                 if (inode) {
4990                         spin_unlock(&root->inode_lock);
4991                         if (atomic_read(&inode->i_count) > 1)
4992                                 d_prune_aliases(inode);
4993                         /*
4994                          * btrfs_drop_inode will have it removed from
4995                          * the inode cache when its usage count
4996                          * hits zero.
4997                          */
4998                         iput(inode);
4999                         cond_resched();
5000                         spin_lock(&root->inode_lock);
5001                         goto again;
5002                 }
5003
5004                 if (cond_resched_lock(&root->inode_lock))
5005                         goto again;
5006
5007                 node = rb_next(node);
5008         }
5009         spin_unlock(&root->inode_lock);
5010 }
5011
5012 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5013 {
5014         struct btrfs_iget_args *args = p;
5015         inode->i_ino = args->location->objectid;
5016         memcpy(&BTRFS_I(inode)->location, args->location,
5017                sizeof(*args->location));
5018         BTRFS_I(inode)->root = args->root;
5019         return 0;
5020 }
5021
5022 static int btrfs_find_actor(struct inode *inode, void *opaque)
5023 {
5024         struct btrfs_iget_args *args = opaque;
5025         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5026                 args->root == BTRFS_I(inode)->root;
5027 }
5028
5029 static struct inode *btrfs_iget_locked(struct super_block *s,
5030                                        struct btrfs_key *location,
5031                                        struct btrfs_root *root)
5032 {
5033         struct inode *inode;
5034         struct btrfs_iget_args args;
5035         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5036
5037         args.location = location;
5038         args.root = root;
5039
5040         inode = iget5_locked(s, hashval, btrfs_find_actor,
5041                              btrfs_init_locked_inode,
5042                              (void *)&args);
5043         return inode;
5044 }
5045
5046 /* Get an inode object given its location and corresponding root.
5047  * Returns in *is_new if the inode was read from disk
5048  */
5049 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5050                          struct btrfs_root *root, int *new)
5051 {
5052         struct inode *inode;
5053
5054         inode = btrfs_iget_locked(s, location, root);
5055         if (!inode)
5056                 return ERR_PTR(-ENOMEM);
5057
5058         if (inode->i_state & I_NEW) {
5059                 btrfs_read_locked_inode(inode);
5060                 if (!is_bad_inode(inode)) {
5061                         inode_tree_add(inode);
5062                         unlock_new_inode(inode);
5063                         if (new)
5064                                 *new = 1;
5065                 } else {
5066                         unlock_new_inode(inode);
5067                         iput(inode);
5068                         inode = ERR_PTR(-ESTALE);
5069                 }
5070         }
5071
5072         return inode;
5073 }
5074
5075 static struct inode *new_simple_dir(struct super_block *s,
5076                                     struct btrfs_key *key,
5077                                     struct btrfs_root *root)
5078 {
5079         struct inode *inode = new_inode(s);
5080
5081         if (!inode)
5082                 return ERR_PTR(-ENOMEM);
5083
5084         BTRFS_I(inode)->root = root;
5085         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5086         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5087
5088         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5089         inode->i_op = &btrfs_dir_ro_inode_operations;
5090         inode->i_fop = &simple_dir_operations;
5091         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5092         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5093
5094         return inode;
5095 }
5096
5097 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5098 {
5099         struct inode *inode;
5100         struct btrfs_root *root = BTRFS_I(dir)->root;
5101         struct btrfs_root *sub_root = root;
5102         struct btrfs_key location;
5103         int index;
5104         int ret = 0;
5105
5106         if (dentry->d_name.len > BTRFS_NAME_LEN)
5107                 return ERR_PTR(-ENAMETOOLONG);
5108
5109         ret = btrfs_inode_by_name(dir, dentry, &location);
5110         if (ret < 0)
5111                 return ERR_PTR(ret);
5112
5113         if (location.objectid == 0)
5114                 return ERR_PTR(-ENOENT);
5115
5116         if (location.type == BTRFS_INODE_ITEM_KEY) {
5117                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5118                 return inode;
5119         }
5120
5121         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
5122
5123         index = srcu_read_lock(&root->fs_info->subvol_srcu);
5124         ret = fixup_tree_root_location(root, dir, dentry,
5125                                        &location, &sub_root);
5126         if (ret < 0) {
5127                 if (ret != -ENOENT)
5128                         inode = ERR_PTR(ret);
5129                 else
5130                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5131         } else {
5132                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5133         }
5134         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
5135
5136         if (!IS_ERR(inode) && root != sub_root) {
5137                 down_read(&root->fs_info->cleanup_work_sem);
5138                 if (!(inode->i_sb->s_flags & MS_RDONLY))
5139                         ret = btrfs_orphan_cleanup(sub_root);
5140                 up_read(&root->fs_info->cleanup_work_sem);
5141                 if (ret) {
5142                         iput(inode);
5143                         inode = ERR_PTR(ret);
5144                 }
5145         }
5146
5147         return inode;
5148 }
5149
5150 static int btrfs_dentry_delete(const struct dentry *dentry)
5151 {
5152         struct btrfs_root *root;
5153         struct inode *inode = dentry->d_inode;
5154
5155         if (!inode && !IS_ROOT(dentry))
5156                 inode = dentry->d_parent->d_inode;
5157
5158         if (inode) {
5159                 root = BTRFS_I(inode)->root;
5160                 if (btrfs_root_refs(&root->root_item) == 0)
5161                         return 1;
5162
5163                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5164                         return 1;
5165         }
5166         return 0;
5167 }
5168
5169 static void btrfs_dentry_release(struct dentry *dentry)
5170 {
5171         if (dentry->d_fsdata)
5172                 kfree(dentry->d_fsdata);
5173 }
5174
5175 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5176                                    unsigned int flags)
5177 {
5178         struct inode *inode;
5179
5180         inode = btrfs_lookup_dentry(dir, dentry);
5181         if (IS_ERR(inode)) {
5182                 if (PTR_ERR(inode) == -ENOENT)
5183                         inode = NULL;
5184                 else
5185                         return ERR_CAST(inode);
5186         }
5187
5188         return d_materialise_unique(dentry, inode);
5189 }
5190
5191 unsigned char btrfs_filetype_table[] = {
5192         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5193 };
5194
5195 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5196 {
5197         struct inode *inode = file_inode(file);
5198         struct btrfs_root *root = BTRFS_I(inode)->root;
5199         struct btrfs_item *item;
5200         struct btrfs_dir_item *di;
5201         struct btrfs_key key;
5202         struct btrfs_key found_key;
5203         struct btrfs_path *path;
5204         struct list_head ins_list;
5205         struct list_head del_list;
5206         int ret;
5207         struct extent_buffer *leaf;
5208         int slot;
5209         unsigned char d_type;
5210         int over = 0;
5211         u32 di_cur;
5212         u32 di_total;
5213         u32 di_len;
5214         int key_type = BTRFS_DIR_INDEX_KEY;
5215         char tmp_name[32];
5216         char *name_ptr;
5217         int name_len;
5218         int is_curr = 0;        /* ctx->pos points to the current index? */
5219
5220         /* FIXME, use a real flag for deciding about the key type */
5221         if (root->fs_info->tree_root == root)
5222                 key_type = BTRFS_DIR_ITEM_KEY;
5223
5224         if (!dir_emit_dots(file, ctx))
5225                 return 0;
5226
5227         path = btrfs_alloc_path();
5228         if (!path)
5229                 return -ENOMEM;
5230
5231         path->reada = 1;
5232
5233         if (key_type == BTRFS_DIR_INDEX_KEY) {
5234                 INIT_LIST_HEAD(&ins_list);
5235                 INIT_LIST_HEAD(&del_list);
5236                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
5237         }
5238
5239         btrfs_set_key_type(&key, key_type);
5240         key.offset = ctx->pos;
5241         key.objectid = btrfs_ino(inode);
5242
5243         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5244         if (ret < 0)
5245                 goto err;
5246
5247         while (1) {
5248                 leaf = path->nodes[0];
5249                 slot = path->slots[0];
5250                 if (slot >= btrfs_header_nritems(leaf)) {
5251                         ret = btrfs_next_leaf(root, path);
5252                         if (ret < 0)
5253                                 goto err;
5254                         else if (ret > 0)
5255                                 break;
5256                         continue;
5257                 }
5258
5259                 item = btrfs_item_nr(slot);
5260                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5261
5262                 if (found_key.objectid != key.objectid)
5263                         break;
5264                 if (btrfs_key_type(&found_key) != key_type)
5265                         break;
5266                 if (found_key.offset < ctx->pos)
5267                         goto next;
5268                 if (key_type == BTRFS_DIR_INDEX_KEY &&
5269                     btrfs_should_delete_dir_index(&del_list,
5270                                                   found_key.offset))
5271                         goto next;
5272
5273                 ctx->pos = found_key.offset;
5274                 is_curr = 1;
5275
5276                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5277                 di_cur = 0;
5278                 di_total = btrfs_item_size(leaf, item);
5279
5280                 while (di_cur < di_total) {
5281                         struct btrfs_key location;
5282
5283                         if (verify_dir_item(root, leaf, di))
5284                                 break;
5285
5286                         name_len = btrfs_dir_name_len(leaf, di);
5287                         if (name_len <= sizeof(tmp_name)) {
5288                                 name_ptr = tmp_name;
5289                         } else {
5290                                 name_ptr = kmalloc(name_len, GFP_NOFS);
5291                                 if (!name_ptr) {
5292                                         ret = -ENOMEM;
5293                                         goto err;
5294                                 }
5295                         }
5296                         read_extent_buffer(leaf, name_ptr,
5297                                            (unsigned long)(di + 1), name_len);
5298
5299                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
5300                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
5301
5302
5303                         /* is this a reference to our own snapshot? If so
5304                          * skip it.
5305                          *
5306                          * In contrast to old kernels, we insert the snapshot's
5307                          * dir item and dir index after it has been created, so
5308                          * we won't find a reference to our own snapshot. We
5309                          * still keep the following code for backward
5310                          * compatibility.
5311                          */
5312                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
5313                             location.objectid == root->root_key.objectid) {
5314                                 over = 0;
5315                                 goto skip;
5316                         }
5317                         over = !dir_emit(ctx, name_ptr, name_len,
5318                                        location.objectid, d_type);
5319
5320 skip:
5321                         if (name_ptr != tmp_name)
5322                                 kfree(name_ptr);
5323
5324                         if (over)
5325                                 goto nopos;
5326                         di_len = btrfs_dir_name_len(leaf, di) +
5327                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
5328                         di_cur += di_len;
5329                         di = (struct btrfs_dir_item *)((char *)di + di_len);
5330                 }
5331 next:
5332                 path->slots[0]++;
5333         }
5334
5335         if (key_type == BTRFS_DIR_INDEX_KEY) {
5336                 if (is_curr)
5337                         ctx->pos++;
5338                 ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5339                 if (ret)
5340                         goto nopos;
5341         }
5342
5343         /* Reached end of directory/root. Bump pos past the last item. */
5344         ctx->pos++;
5345
5346         /*
5347          * Stop new entries from being returned after we return the last
5348          * entry.
5349          *
5350          * New directory entries are assigned a strictly increasing
5351          * offset.  This means that new entries created during readdir
5352          * are *guaranteed* to be seen in the future by that readdir.
5353          * This has broken buggy programs which operate on names as
5354          * they're returned by readdir.  Until we re-use freed offsets
5355          * we have this hack to stop new entries from being returned
5356          * under the assumption that they'll never reach this huge
5357          * offset.
5358          *
5359          * This is being careful not to overflow 32bit loff_t unless the
5360          * last entry requires it because doing so has broken 32bit apps
5361          * in the past.
5362          */
5363         if (key_type == BTRFS_DIR_INDEX_KEY) {
5364                 if (ctx->pos >= INT_MAX)
5365                         ctx->pos = LLONG_MAX;
5366                 else
5367                         ctx->pos = INT_MAX;
5368         }
5369 nopos:
5370         ret = 0;
5371 err:
5372         if (key_type == BTRFS_DIR_INDEX_KEY)
5373                 btrfs_put_delayed_items(&ins_list, &del_list);
5374         btrfs_free_path(path);
5375         return ret;
5376 }
5377
5378 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
5379 {
5380         struct btrfs_root *root = BTRFS_I(inode)->root;
5381         struct btrfs_trans_handle *trans;
5382         int ret = 0;
5383         bool nolock = false;
5384
5385         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5386                 return 0;
5387
5388         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
5389                 nolock = true;
5390
5391         if (wbc->sync_mode == WB_SYNC_ALL) {
5392                 if (nolock)
5393                         trans = btrfs_join_transaction_nolock(root);
5394                 else
5395                         trans = btrfs_join_transaction(root);
5396                 if (IS_ERR(trans))
5397                         return PTR_ERR(trans);
5398                 ret = btrfs_commit_transaction(trans, root);
5399         }
5400         return ret;
5401 }
5402
5403 /*
5404  * This is somewhat expensive, updating the tree every time the
5405  * inode changes.  But, it is most likely to find the inode in cache.
5406  * FIXME, needs more benchmarking...there are no reasons other than performance
5407  * to keep or drop this code.
5408  */
5409 static int btrfs_dirty_inode(struct inode *inode)
5410 {
5411         struct btrfs_root *root = BTRFS_I(inode)->root;
5412         struct btrfs_trans_handle *trans;
5413         int ret;
5414
5415         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5416                 return 0;
5417
5418         trans = btrfs_join_transaction(root);
5419         if (IS_ERR(trans))
5420                 return PTR_ERR(trans);
5421
5422         ret = btrfs_update_inode(trans, root, inode);
5423         if (ret && ret == -ENOSPC) {
5424                 /* whoops, lets try again with the full transaction */
5425                 btrfs_end_transaction(trans, root);
5426                 trans = btrfs_start_transaction(root, 1);
5427                 if (IS_ERR(trans))
5428                         return PTR_ERR(trans);
5429
5430                 ret = btrfs_update_inode(trans, root, inode);
5431         }
5432         btrfs_end_transaction(trans, root);
5433         if (BTRFS_I(inode)->delayed_node)
5434                 btrfs_balance_delayed_items(root);
5435
5436         return ret;
5437 }
5438
5439 /*
5440  * This is a copy of file_update_time.  We need this so we can return error on
5441  * ENOSPC for updating the inode in the case of file write and mmap writes.
5442  */
5443 static int btrfs_update_time(struct inode *inode, struct timespec *now,
5444                              int flags)
5445 {
5446         struct btrfs_root *root = BTRFS_I(inode)->root;
5447
5448         if (btrfs_root_readonly(root))
5449                 return -EROFS;
5450
5451         if (flags & S_VERSION)
5452                 inode_inc_iversion(inode);
5453         if (flags & S_CTIME)
5454                 inode->i_ctime = *now;
5455         if (flags & S_MTIME)
5456                 inode->i_mtime = *now;
5457         if (flags & S_ATIME)
5458                 inode->i_atime = *now;
5459         return btrfs_dirty_inode(inode);
5460 }
5461
5462 /*
5463  * find the highest existing sequence number in a directory
5464  * and then set the in-memory index_cnt variable to reflect
5465  * free sequence numbers
5466  */
5467 static int btrfs_set_inode_index_count(struct inode *inode)
5468 {
5469         struct btrfs_root *root = BTRFS_I(inode)->root;
5470         struct btrfs_key key, found_key;
5471         struct btrfs_path *path;
5472         struct extent_buffer *leaf;
5473         int ret;
5474
5475         key.objectid = btrfs_ino(inode);
5476         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
5477         key.offset = (u64)-1;
5478
5479         path = btrfs_alloc_path();
5480         if (!path)
5481                 return -ENOMEM;
5482
5483         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5484         if (ret < 0)
5485                 goto out;
5486         /* FIXME: we should be able to handle this */
5487         if (ret == 0)
5488                 goto out;
5489         ret = 0;
5490
5491         /*
5492          * MAGIC NUMBER EXPLANATION:
5493          * since we search a directory based on f_pos we have to start at 2
5494          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
5495          * else has to start at 2
5496          */
5497         if (path->slots[0] == 0) {
5498                 BTRFS_I(inode)->index_cnt = 2;
5499                 goto out;
5500         }
5501
5502         path->slots[0]--;
5503
5504         leaf = path->nodes[0];
5505         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5506
5507         if (found_key.objectid != btrfs_ino(inode) ||
5508             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
5509                 BTRFS_I(inode)->index_cnt = 2;
5510                 goto out;
5511         }
5512
5513         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
5514 out:
5515         btrfs_free_path(path);
5516         return ret;
5517 }
5518
5519 /*
5520  * helper to find a free sequence number in a given directory.  This current
5521  * code is very simple, later versions will do smarter things in the btree
5522  */
5523 int btrfs_set_inode_index(struct inode *dir, u64 *index)
5524 {
5525         int ret = 0;
5526
5527         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
5528                 ret = btrfs_inode_delayed_dir_index_count(dir);
5529                 if (ret) {
5530                         ret = btrfs_set_inode_index_count(dir);
5531                         if (ret)
5532                                 return ret;
5533                 }
5534         }
5535
5536         *index = BTRFS_I(dir)->index_cnt;
5537         BTRFS_I(dir)->index_cnt++;
5538
5539         return ret;
5540 }
5541
5542 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
5543                                      struct btrfs_root *root,
5544                                      struct inode *dir,
5545                                      const char *name, int name_len,
5546                                      u64 ref_objectid, u64 objectid,
5547                                      umode_t mode, u64 *index)
5548 {
5549         struct inode *inode;
5550         struct btrfs_inode_item *inode_item;
5551         struct btrfs_key *location;
5552         struct btrfs_path *path;
5553         struct btrfs_inode_ref *ref;
5554         struct btrfs_key key[2];
5555         u32 sizes[2];
5556         unsigned long ptr;
5557         int ret;
5558
5559         path = btrfs_alloc_path();
5560         if (!path)
5561                 return ERR_PTR(-ENOMEM);
5562
5563         inode = new_inode(root->fs_info->sb);
5564         if (!inode) {
5565                 btrfs_free_path(path);
5566                 return ERR_PTR(-ENOMEM);
5567         }
5568
5569         /*
5570          * we have to initialize this early, so we can reclaim the inode
5571          * number if we fail afterwards in this function.
5572          */
5573         inode->i_ino = objectid;
5574
5575         if (dir) {
5576                 trace_btrfs_inode_request(dir);
5577
5578                 ret = btrfs_set_inode_index(dir, index);
5579                 if (ret) {
5580                         btrfs_free_path(path);
5581                         iput(inode);
5582                         return ERR_PTR(ret);
5583                 }
5584         }
5585         /*
5586          * index_cnt is ignored for everything but a dir,
5587          * btrfs_get_inode_index_count has an explanation for the magic
5588          * number
5589          */
5590         BTRFS_I(inode)->index_cnt = 2;
5591         BTRFS_I(inode)->dir_index = *index;
5592         BTRFS_I(inode)->root = root;
5593         BTRFS_I(inode)->generation = trans->transid;
5594         inode->i_generation = BTRFS_I(inode)->generation;
5595
5596         /*
5597          * We could have gotten an inode number from somebody who was fsynced
5598          * and then removed in this same transaction, so let's just set full
5599          * sync since it will be a full sync anyway and this will blow away the
5600          * old info in the log.
5601          */
5602         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
5603
5604         key[0].objectid = objectid;
5605         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
5606         key[0].offset = 0;
5607
5608         /*
5609          * Start new inodes with an inode_ref. This is slightly more
5610          * efficient for small numbers of hard links since they will
5611          * be packed into one item. Extended refs will kick in if we
5612          * add more hard links than can fit in the ref item.
5613          */
5614         key[1].objectid = objectid;
5615         btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
5616         key[1].offset = ref_objectid;
5617
5618         sizes[0] = sizeof(struct btrfs_inode_item);
5619         sizes[1] = name_len + sizeof(*ref);
5620
5621         path->leave_spinning = 1;
5622         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
5623         if (ret != 0)
5624                 goto fail;
5625
5626         inode_init_owner(inode, dir, mode);
5627         inode_set_bytes(inode, 0);
5628         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5629         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
5630                                   struct btrfs_inode_item);
5631         memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
5632                              sizeof(*inode_item));
5633         fill_inode_item(trans, path->nodes[0], inode_item, inode);
5634
5635         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
5636                              struct btrfs_inode_ref);
5637         btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
5638         btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
5639         ptr = (unsigned long)(ref + 1);
5640         write_extent_buffer(path->nodes[0], name, ptr, name_len);
5641
5642         btrfs_mark_buffer_dirty(path->nodes[0]);
5643         btrfs_free_path(path);
5644
5645         location = &BTRFS_I(inode)->location;
5646         location->objectid = objectid;
5647         location->offset = 0;
5648         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
5649
5650         btrfs_inherit_iflags(inode, dir);
5651
5652         if (S_ISREG(mode)) {
5653                 if (btrfs_test_opt(root, NODATASUM))
5654                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
5655                 if (btrfs_test_opt(root, NODATACOW))
5656                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
5657                                 BTRFS_INODE_NODATASUM;
5658         }
5659
5660         btrfs_insert_inode_hash(inode);
5661         inode_tree_add(inode);
5662
5663         trace_btrfs_inode_new(inode);
5664         btrfs_set_inode_last_trans(trans, inode);
5665
5666         btrfs_update_root_times(trans, root);
5667
5668         ret = btrfs_inode_inherit_props(trans, inode, dir);
5669         if (ret)
5670                 btrfs_err(root->fs_info,
5671                           "error inheriting props for ino %llu (root %llu): %d",
5672                           btrfs_ino(inode), root->root_key.objectid, ret);
5673
5674         return inode;
5675 fail:
5676         if (dir)
5677                 BTRFS_I(dir)->index_cnt--;
5678         btrfs_free_path(path);
5679         iput(inode);
5680         return ERR_PTR(ret);
5681 }
5682
5683 static inline u8 btrfs_inode_type(struct inode *inode)
5684 {
5685         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
5686 }
5687
5688 /*
5689  * utility function to add 'inode' into 'parent_inode' with
5690  * a give name and a given sequence number.
5691  * if 'add_backref' is true, also insert a backref from the
5692  * inode to the parent directory.
5693  */
5694 int btrfs_add_link(struct btrfs_trans_handle *trans,
5695                    struct inode *parent_inode, struct inode *inode,
5696                    const char *name, int name_len, int add_backref, u64 index)
5697 {
5698         int ret = 0;
5699         struct btrfs_key key;
5700         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
5701         u64 ino = btrfs_ino(inode);
5702         u64 parent_ino = btrfs_ino(parent_inode);
5703
5704         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5705                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
5706         } else {
5707                 key.objectid = ino;
5708                 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
5709                 key.offset = 0;
5710         }
5711
5712         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5713                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
5714                                          key.objectid, root->root_key.objectid,
5715                                          parent_ino, index, name, name_len);
5716         } else if (add_backref) {
5717                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
5718                                              parent_ino, index);
5719         }
5720
5721         /* Nothing to clean up yet */
5722         if (ret)
5723                 return ret;
5724
5725         ret = btrfs_insert_dir_item(trans, root, name, name_len,
5726                                     parent_inode, &key,
5727                                     btrfs_inode_type(inode), index);
5728         if (ret == -EEXIST || ret == -EOVERFLOW)
5729                 goto fail_dir_item;
5730         else if (ret) {
5731                 btrfs_abort_transaction(trans, root, ret);
5732                 return ret;
5733         }
5734
5735         btrfs_i_size_write(parent_inode, parent_inode->i_size +
5736                            name_len * 2);
5737         inode_inc_iversion(parent_inode);
5738         parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
5739         ret = btrfs_update_inode(trans, root, parent_inode);
5740         if (ret)
5741                 btrfs_abort_transaction(trans, root, ret);
5742         return ret;
5743
5744 fail_dir_item:
5745         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5746                 u64 local_index;
5747                 int err;
5748                 err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
5749                                  key.objectid, root->root_key.objectid,
5750                                  parent_ino, &local_index, name, name_len);
5751
5752         } else if (add_backref) {
5753                 u64 local_index;
5754                 int err;
5755
5756                 err = btrfs_del_inode_ref(trans, root, name, name_len,
5757                                           ino, parent_ino, &local_index);
5758         }
5759         return ret;
5760 }
5761
5762 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
5763                             struct inode *dir, struct dentry *dentry,
5764                             struct inode *inode, int backref, u64 index)
5765 {
5766         int err = btrfs_add_link(trans, dir, inode,
5767                                  dentry->d_name.name, dentry->d_name.len,
5768                                  backref, index);
5769         if (err > 0)
5770                 err = -EEXIST;
5771         return err;
5772 }
5773
5774 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
5775                         umode_t mode, dev_t rdev)
5776 {
5777         struct btrfs_trans_handle *trans;
5778         struct btrfs_root *root = BTRFS_I(dir)->root;
5779         struct inode *inode = NULL;
5780         int err;
5781         int drop_inode = 0;
5782         u64 objectid;
5783         u64 index = 0;
5784
5785         if (!new_valid_dev(rdev))
5786                 return -EINVAL;
5787
5788         /*
5789          * 2 for inode item and ref
5790          * 2 for dir items
5791          * 1 for xattr if selinux is on
5792          */
5793         trans = btrfs_start_transaction(root, 5);
5794         if (IS_ERR(trans))
5795                 return PTR_ERR(trans);
5796
5797         err = btrfs_find_free_ino(root, &objectid);
5798         if (err)
5799                 goto out_unlock;
5800
5801         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5802                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5803                                 mode, &index);
5804         if (IS_ERR(inode)) {
5805                 err = PTR_ERR(inode);
5806                 goto out_unlock;
5807         }
5808
5809         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5810         if (err) {
5811                 drop_inode = 1;
5812                 goto out_unlock;
5813         }
5814
5815         /*
5816         * If the active LSM wants to access the inode during
5817         * d_instantiate it needs these. Smack checks to see
5818         * if the filesystem supports xattrs by looking at the
5819         * ops vector.
5820         */
5821
5822         inode->i_op = &btrfs_special_inode_operations;
5823         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
5824         if (err)
5825                 drop_inode = 1;
5826         else {
5827                 init_special_inode(inode, inode->i_mode, rdev);
5828                 btrfs_update_inode(trans, root, inode);
5829                 d_instantiate(dentry, inode);
5830         }
5831 out_unlock:
5832         btrfs_end_transaction(trans, root);
5833         btrfs_balance_delayed_items(root);
5834         btrfs_btree_balance_dirty(root);
5835         if (drop_inode) {
5836                 inode_dec_link_count(inode);
5837                 iput(inode);
5838         }
5839         return err;
5840 }
5841
5842 static int btrfs_create(struct inode *dir, struct dentry *dentry,
5843                         umode_t mode, bool excl)
5844 {
5845         struct btrfs_trans_handle *trans;
5846         struct btrfs_root *root = BTRFS_I(dir)->root;
5847         struct inode *inode = NULL;
5848         int drop_inode_on_err = 0;
5849         int err;
5850         u64 objectid;
5851         u64 index = 0;
5852
5853         /*
5854          * 2 for inode item and ref
5855          * 2 for dir items
5856          * 1 for xattr if selinux is on
5857          */
5858         trans = btrfs_start_transaction(root, 5);
5859         if (IS_ERR(trans))
5860                 return PTR_ERR(trans);
5861
5862         err = btrfs_find_free_ino(root, &objectid);
5863         if (err)
5864                 goto out_unlock;
5865
5866         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5867                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5868                                 mode, &index);
5869         if (IS_ERR(inode)) {
5870                 err = PTR_ERR(inode);
5871                 goto out_unlock;
5872         }
5873         drop_inode_on_err = 1;
5874
5875         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5876         if (err)
5877                 goto out_unlock;
5878
5879         err = btrfs_update_inode(trans, root, inode);
5880         if (err)
5881                 goto out_unlock;
5882
5883         /*
5884         * If the active LSM wants to access the inode during
5885         * d_instantiate it needs these. Smack checks to see
5886         * if the filesystem supports xattrs by looking at the
5887         * ops vector.
5888         */
5889         inode->i_fop = &btrfs_file_operations;
5890         inode->i_op = &btrfs_file_inode_operations;
5891
5892         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
5893         if (err)
5894                 goto out_unlock;
5895
5896         inode->i_mapping->a_ops = &btrfs_aops;
5897         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
5898         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
5899         d_instantiate(dentry, inode);
5900
5901 out_unlock:
5902         btrfs_end_transaction(trans, root);
5903         if (err && drop_inode_on_err) {
5904                 inode_dec_link_count(inode);
5905                 iput(inode);
5906         }
5907         btrfs_balance_delayed_items(root);
5908         btrfs_btree_balance_dirty(root);
5909         return err;
5910 }
5911
5912 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
5913                       struct dentry *dentry)
5914 {
5915         struct btrfs_trans_handle *trans;
5916         struct btrfs_root *root = BTRFS_I(dir)->root;
5917         struct inode *inode = old_dentry->d_inode;
5918         u64 index;
5919         int err;
5920         int drop_inode = 0;
5921
5922         /* do not allow sys_link's with other subvols of the same device */
5923         if (root->objectid != BTRFS_I(inode)->root->objectid)
5924                 return -EXDEV;
5925
5926         if (inode->i_nlink >= BTRFS_LINK_MAX)
5927                 return -EMLINK;
5928
5929         err = btrfs_set_inode_index(dir, &index);
5930         if (err)
5931                 goto fail;
5932
5933         /*
5934          * 2 items for inode and inode ref
5935          * 2 items for dir items
5936          * 1 item for parent inode
5937          */
5938         trans = btrfs_start_transaction(root, 5);
5939         if (IS_ERR(trans)) {
5940                 err = PTR_ERR(trans);
5941                 goto fail;
5942         }
5943
5944         /* There are several dir indexes for this inode, clear the cache. */
5945         BTRFS_I(inode)->dir_index = 0ULL;
5946         inc_nlink(inode);
5947         inode_inc_iversion(inode);
5948         inode->i_ctime = CURRENT_TIME;
5949         ihold(inode);
5950         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
5951
5952         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
5953
5954         if (err) {
5955                 drop_inode = 1;
5956         } else {
5957                 struct dentry *parent = dentry->d_parent;
5958                 err = btrfs_update_inode(trans, root, inode);
5959                 if (err)
5960                         goto fail;
5961                 d_instantiate(dentry, inode);
5962                 btrfs_log_new_name(trans, inode, NULL, parent);
5963         }
5964
5965         btrfs_end_transaction(trans, root);
5966         btrfs_balance_delayed_items(root);
5967 fail:
5968         if (drop_inode) {
5969                 inode_dec_link_count(inode);
5970                 iput(inode);
5971         }
5972         btrfs_btree_balance_dirty(root);
5973         return err;
5974 }
5975
5976 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
5977 {
5978         struct inode *inode = NULL;
5979         struct btrfs_trans_handle *trans;
5980         struct btrfs_root *root = BTRFS_I(dir)->root;
5981         int err = 0;
5982         int drop_on_err = 0;
5983         u64 objectid = 0;
5984         u64 index = 0;
5985
5986         /*
5987          * 2 items for inode and ref
5988          * 2 items for dir items
5989          * 1 for xattr if selinux is on
5990          */
5991         trans = btrfs_start_transaction(root, 5);
5992         if (IS_ERR(trans))
5993                 return PTR_ERR(trans);
5994
5995         err = btrfs_find_free_ino(root, &objectid);
5996         if (err)
5997                 goto out_fail;
5998
5999         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6000                                 dentry->d_name.len, btrfs_ino(dir), objectid,
6001                                 S_IFDIR | mode, &index);
6002         if (IS_ERR(inode)) {
6003                 err = PTR_ERR(inode);
6004                 goto out_fail;
6005         }
6006
6007         drop_on_err = 1;
6008
6009         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6010         if (err)
6011                 goto out_fail;
6012
6013         inode->i_op = &btrfs_dir_inode_operations;
6014         inode->i_fop = &btrfs_dir_file_operations;
6015
6016         btrfs_i_size_write(inode, 0);
6017         err = btrfs_update_inode(trans, root, inode);
6018         if (err)
6019                 goto out_fail;
6020
6021         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
6022                              dentry->d_name.len, 0, index);
6023         if (err)
6024                 goto out_fail;
6025
6026         d_instantiate(dentry, inode);
6027         drop_on_err = 0;
6028
6029 out_fail:
6030         btrfs_end_transaction(trans, root);
6031         if (drop_on_err)
6032                 iput(inode);
6033         btrfs_balance_delayed_items(root);
6034         btrfs_btree_balance_dirty(root);
6035         return err;
6036 }
6037
6038 /* helper for btfs_get_extent.  Given an existing extent in the tree,
6039  * and an extent that you want to insert, deal with overlap and insert
6040  * the new extent into the tree.
6041  */
6042 static int merge_extent_mapping(struct extent_map_tree *em_tree,
6043                                 struct extent_map *existing,
6044                                 struct extent_map *em,
6045                                 u64 map_start, u64 map_len)
6046 {
6047         u64 start_diff;
6048
6049         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
6050         start_diff = map_start - em->start;
6051         em->start = map_start;
6052         em->len = map_len;
6053         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
6054             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
6055                 em->block_start += start_diff;
6056                 em->block_len -= start_diff;
6057         }
6058         return add_extent_mapping(em_tree, em, 0);
6059 }
6060
6061 static noinline int uncompress_inline(struct btrfs_path *path,
6062                                       struct inode *inode, struct page *page,
6063                                       size_t pg_offset, u64 extent_offset,
6064                                       struct btrfs_file_extent_item *item)
6065 {
6066         int ret;
6067         struct extent_buffer *leaf = path->nodes[0];
6068         char *tmp;
6069         size_t max_size;
6070         unsigned long inline_size;
6071         unsigned long ptr;
6072         int compress_type;
6073
6074         WARN_ON(pg_offset != 0);
6075         compress_type = btrfs_file_extent_compression(leaf, item);
6076         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6077         inline_size = btrfs_file_extent_inline_item_len(leaf,
6078                                         btrfs_item_nr(path->slots[0]));
6079         tmp = kmalloc(inline_size, GFP_NOFS);
6080         if (!tmp)
6081                 return -ENOMEM;
6082         ptr = btrfs_file_extent_inline_start(item);
6083
6084         read_extent_buffer(leaf, tmp, ptr, inline_size);
6085
6086         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
6087         ret = btrfs_decompress(compress_type, tmp, page,
6088                                extent_offset, inline_size, max_size);
6089         if (ret) {
6090                 char *kaddr = kmap_atomic(page);
6091                 unsigned long copy_size = min_t(u64,
6092                                   PAGE_CACHE_SIZE - pg_offset,
6093                                   max_size - extent_offset);
6094                 memset(kaddr + pg_offset, 0, copy_size);
6095                 kunmap_atomic(kaddr);
6096         }
6097         kfree(tmp);
6098         return 0;
6099 }
6100
6101 /*
6102  * a bit scary, this does extent mapping from logical file offset to the disk.
6103  * the ugly parts come from merging extents from the disk with the in-ram
6104  * representation.  This gets more complex because of the data=ordered code,
6105  * where the in-ram extents might be locked pending data=ordered completion.
6106  *
6107  * This also copies inline extents directly into the page.
6108  */
6109
6110 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
6111                                     size_t pg_offset, u64 start, u64 len,
6112                                     int create)
6113 {
6114         int ret;
6115         int err = 0;
6116         u64 bytenr;
6117         u64 extent_start = 0;
6118         u64 extent_end = 0;
6119         u64 objectid = btrfs_ino(inode);
6120         u32 found_type;
6121         struct btrfs_path *path = NULL;
6122         struct btrfs_root *root = BTRFS_I(inode)->root;
6123         struct btrfs_file_extent_item *item;
6124         struct extent_buffer *leaf;
6125         struct btrfs_key found_key;
6126         struct extent_map *em = NULL;
6127         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
6128         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6129         struct btrfs_trans_handle *trans = NULL;
6130         int compress_type;
6131
6132 again:
6133         read_lock(&em_tree->lock);
6134         em = lookup_extent_mapping(em_tree, start, len);
6135         if (em)
6136                 em->bdev = root->fs_info->fs_devices->latest_bdev;
6137         read_unlock(&em_tree->lock);
6138
6139         if (em) {
6140                 if (em->start > start || em->start + em->len <= start)
6141                         free_extent_map(em);
6142                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6143                         free_extent_map(em);
6144                 else
6145                         goto out;
6146         }
6147         em = alloc_extent_map();
6148         if (!em) {
6149                 err = -ENOMEM;
6150                 goto out;
6151         }
6152         em->bdev = root->fs_info->fs_devices->latest_bdev;
6153         em->start = EXTENT_MAP_HOLE;
6154         em->orig_start = EXTENT_MAP_HOLE;
6155         em->len = (u64)-1;
6156         em->block_len = (u64)-1;
6157
6158         if (!path) {
6159                 path = btrfs_alloc_path();
6160                 if (!path) {
6161                         err = -ENOMEM;
6162                         goto out;
6163                 }
6164                 /*
6165                  * Chances are we'll be called again, so go ahead and do
6166                  * readahead
6167                  */
6168                 path->reada = 1;
6169         }
6170
6171         ret = btrfs_lookup_file_extent(trans, root, path,
6172                                        objectid, start, trans != NULL);
6173         if (ret < 0) {
6174                 err = ret;
6175                 goto out;
6176         }
6177
6178         if (ret != 0) {
6179                 if (path->slots[0] == 0)
6180                         goto not_found;
6181                 path->slots[0]--;
6182         }
6183
6184         leaf = path->nodes[0];
6185         item = btrfs_item_ptr(leaf, path->slots[0],
6186                               struct btrfs_file_extent_item);
6187         /* are we inside the extent that was found? */
6188         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6189         found_type = btrfs_key_type(&found_key);
6190         if (found_key.objectid != objectid ||
6191             found_type != BTRFS_EXTENT_DATA_KEY) {
6192                 /*
6193                  * If we backup past the first extent we want to move forward
6194                  * and see if there is an extent in front of us, otherwise we'll
6195                  * say there is a hole for our whole search range which can
6196                  * cause problems.
6197                  */
6198                 extent_end = start;
6199                 goto next;
6200         }
6201
6202         found_type = btrfs_file_extent_type(leaf, item);
6203         extent_start = found_key.offset;
6204         compress_type = btrfs_file_extent_compression(leaf, item);
6205         if (found_type == BTRFS_FILE_EXTENT_REG ||
6206             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6207                 extent_end = extent_start +
6208                        btrfs_file_extent_num_bytes(leaf, item);
6209         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6210                 size_t size;
6211                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6212                 extent_end = ALIGN(extent_start + size, root->sectorsize);
6213         }
6214 next:
6215         if (start >= extent_end) {
6216                 path->slots[0]++;
6217                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6218                         ret = btrfs_next_leaf(root, path);
6219                         if (ret < 0) {
6220                                 err = ret;
6221                                 goto out;
6222                         }
6223                         if (ret > 0)
6224                                 goto not_found;
6225                         leaf = path->nodes[0];
6226                 }
6227                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6228                 if (found_key.objectid != objectid ||
6229                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6230                         goto not_found;
6231                 if (start + len <= found_key.offset)
6232                         goto not_found;
6233                 em->start = start;
6234                 em->orig_start = start;
6235                 em->len = found_key.offset - start;
6236                 goto not_found_em;
6237         }
6238
6239         em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, item);
6240         if (found_type == BTRFS_FILE_EXTENT_REG ||
6241             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6242                 em->start = extent_start;
6243                 em->len = extent_end - extent_start;
6244                 em->orig_start = extent_start -
6245                                  btrfs_file_extent_offset(leaf, item);
6246                 em->orig_block_len = btrfs_file_extent_disk_num_bytes(leaf,
6247                                                                       item);
6248                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
6249                 if (bytenr == 0) {
6250                         em->block_start = EXTENT_MAP_HOLE;
6251                         goto insert;
6252                 }
6253                 if (compress_type != BTRFS_COMPRESS_NONE) {
6254                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
6255                         em->compress_type = compress_type;
6256                         em->block_start = bytenr;
6257                         em->block_len = em->orig_block_len;
6258                 } else {
6259                         bytenr += btrfs_file_extent_offset(leaf, item);
6260                         em->block_start = bytenr;
6261                         em->block_len = em->len;
6262                         if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
6263                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
6264                 }
6265                 goto insert;
6266         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6267                 unsigned long ptr;
6268                 char *map;
6269                 size_t size;
6270                 size_t extent_offset;
6271                 size_t copy_size;
6272
6273                 em->block_start = EXTENT_MAP_INLINE;
6274                 if (!page || create) {
6275                         em->start = extent_start;
6276                         em->len = extent_end - extent_start;
6277                         goto out;
6278                 }
6279
6280                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6281                 extent_offset = page_offset(page) + pg_offset - extent_start;
6282                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
6283                                 size - extent_offset);
6284                 em->start = extent_start + extent_offset;
6285                 em->len = ALIGN(copy_size, root->sectorsize);
6286                 em->orig_block_len = em->len;
6287                 em->orig_start = em->start;
6288                 if (compress_type) {
6289                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
6290                         em->compress_type = compress_type;
6291                 }
6292                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6293                 if (create == 0 && !PageUptodate(page)) {
6294                         if (btrfs_file_extent_compression(leaf, item) !=
6295                             BTRFS_COMPRESS_NONE) {
6296                                 ret = uncompress_inline(path, inode, page,
6297                                                         pg_offset,
6298                                                         extent_offset, item);
6299                                 BUG_ON(ret); /* -ENOMEM */
6300                         } else {
6301                                 map = kmap(page);
6302                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6303                                                    copy_size);
6304                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
6305                                         memset(map + pg_offset + copy_size, 0,
6306                                                PAGE_CACHE_SIZE - pg_offset -
6307                                                copy_size);
6308                                 }
6309                                 kunmap(page);
6310                         }
6311                         flush_dcache_page(page);
6312                 } else if (create && PageUptodate(page)) {
6313                         BUG();
6314                         if (!trans) {
6315                                 kunmap(page);
6316                                 free_extent_map(em);
6317                                 em = NULL;
6318
6319                                 btrfs_release_path(path);
6320                                 trans = btrfs_join_transaction(root);
6321
6322                                 if (IS_ERR(trans))
6323                                         return ERR_CAST(trans);
6324                                 goto again;
6325                         }
6326                         map = kmap(page);
6327                         write_extent_buffer(leaf, map + pg_offset, ptr,
6328                                             copy_size);
6329                         kunmap(page);
6330                         btrfs_mark_buffer_dirty(leaf);
6331                 }
6332                 set_extent_uptodate(io_tree, em->start,
6333                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6334                 goto insert;
6335         } else {
6336                 WARN(1, KERN_ERR "btrfs unknown found_type %d\n", found_type);
6337         }
6338 not_found:
6339         em->start = start;
6340         em->orig_start = start;
6341         em->len = len;
6342 not_found_em:
6343         em->block_start = EXTENT_MAP_HOLE;
6344         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
6345 insert:
6346         btrfs_release_path(path);
6347         if (em->start > start || extent_map_end(em) <= start) {
6348                 btrfs_err(root->fs_info, "bad extent! em: [%llu %llu] passed [%llu %llu]",
6349                         em->start, em->len, start, len);
6350                 err = -EIO;
6351                 goto out;
6352         }
6353
6354         err = 0;
6355         write_lock(&em_tree->lock);
6356         ret = add_extent_mapping(em_tree, em, 0);
6357         /* it is possible that someone inserted the extent into the tree
6358          * while we had the lock dropped.  It is also possible that
6359          * an overlapping map exists in the tree
6360          */
6361         if (ret == -EEXIST) {
6362                 struct extent_map *existing;
6363
6364                 ret = 0;
6365
6366                 existing = lookup_extent_mapping(em_tree, start, len);
6367                 if (existing && (existing->start > start ||
6368                     existing->start + existing->len <= start)) {
6369                         free_extent_map(existing);
6370                         existing = NULL;
6371                 }
6372                 if (!existing) {
6373                         existing = lookup_extent_mapping(em_tree, em->start,
6374                                                          em->len);
6375                         if (existing) {
6376                                 err = merge_extent_mapping(em_tree, existing,
6377                                                            em, start,
6378                                                            root->sectorsize);
6379                                 free_extent_map(existing);
6380                                 if (err) {
6381                                         free_extent_map(em);
6382                                         em = NULL;
6383                                 }
6384                         } else {
6385                                 err = -EIO;
6386                                 free_extent_map(em);
6387                                 em = NULL;
6388                         }
6389                 } else {
6390                         free_extent_map(em);
6391                         em = existing;
6392                         err = 0;
6393                 }
6394         }
6395         write_unlock(&em_tree->lock);
6396 out:
6397
6398         trace_btrfs_get_extent(root, em);
6399
6400         if (path)
6401                 btrfs_free_path(path);
6402         if (trans) {
6403                 ret = btrfs_end_transaction(trans, root);
6404                 if (!err)
6405                         err = ret;
6406         }
6407         if (err) {
6408                 free_extent_map(em);
6409                 return ERR_PTR(err);
6410         }
6411         BUG_ON(!em); /* Error is always set */
6412         return em;
6413 }
6414
6415 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
6416                                            size_t pg_offset, u64 start, u64 len,
6417                                            int create)
6418 {
6419         struct extent_map *em;
6420         struct extent_map *hole_em = NULL;
6421         u64 range_start = start;
6422         u64 end;
6423         u64 found;
6424         u64 found_end;
6425         int err = 0;
6426
6427         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
6428         if (IS_ERR(em))
6429                 return em;
6430         if (em) {
6431                 /*
6432                  * if our em maps to
6433                  * -  a hole or
6434                  * -  a pre-alloc extent,
6435                  * there might actually be delalloc bytes behind it.
6436                  */
6437                 if (em->block_start != EXTENT_MAP_HOLE &&
6438                     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6439                         return em;
6440                 else
6441                         hole_em = em;
6442         }
6443
6444         /* check to see if we've wrapped (len == -1 or similar) */
6445         end = start + len;
6446         if (end < start)
6447                 end = (u64)-1;
6448         else
6449                 end -= 1;
6450
6451         em = NULL;
6452
6453         /* ok, we didn't find anything, lets look for delalloc */
6454         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
6455                                  end, len, EXTENT_DELALLOC, 1);
6456         found_end = range_start + found;
6457         if (found_end < range_start)
6458                 found_end = (u64)-1;
6459
6460         /*
6461          * we didn't find anything useful, return
6462          * the original results from get_extent()
6463          */
6464         if (range_start > end || found_end <= start) {
6465                 em = hole_em;
6466                 hole_em = NULL;
6467                 goto out;
6468         }
6469
6470         /* adjust the range_start to make sure it doesn't
6471          * go backwards from the start they passed in
6472          */
6473         range_start = max(start, range_start);
6474         found = found_end - range_start;
6475
6476         if (found > 0) {
6477                 u64 hole_start = start;
6478                 u64 hole_len = len;
6479
6480                 em = alloc_extent_map();
6481                 if (!em) {
6482                         err = -ENOMEM;
6483                         goto out;
6484                 }
6485                 /*
6486                  * when btrfs_get_extent can't find anything it
6487                  * returns one huge hole
6488                  *
6489                  * make sure what it found really fits our range, and
6490                  * adjust to make sure it is based on the start from
6491                  * the caller
6492                  */
6493                 if (hole_em) {
6494                         u64 calc_end = extent_map_end(hole_em);
6495
6496                         if (calc_end <= start || (hole_em->start > end)) {
6497                                 free_extent_map(hole_em);
6498                                 hole_em = NULL;
6499                         } else {
6500                                 hole_start = max(hole_em->start, start);
6501                                 hole_len = calc_end - hole_start;
6502                         }
6503                 }
6504                 em->bdev = NULL;
6505                 if (hole_em && range_start > hole_start) {
6506                         /* our hole starts before our delalloc, so we
6507                          * have to return just the parts of the hole
6508                          * that go until  the delalloc starts
6509                          */
6510                         em->len = min(hole_len,
6511                                       range_start - hole_start);
6512                         em->start = hole_start;
6513                         em->orig_start = hole_start;
6514                         /*
6515                          * don't adjust block start at all,
6516                          * it is fixed at EXTENT_MAP_HOLE
6517                          */
6518                         em->block_start = hole_em->block_start;
6519                         em->block_len = hole_len;
6520                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
6521                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
6522                 } else {
6523                         em->start = range_start;
6524                         em->len = found;
6525                         em->orig_start = range_start;
6526                         em->block_start = EXTENT_MAP_DELALLOC;
6527                         em->block_len = found;
6528                 }
6529         } else if (hole_em) {
6530                 return hole_em;
6531         }
6532 out:
6533
6534         free_extent_map(hole_em);
6535         if (err) {
6536                 free_extent_map(em);
6537                 return ERR_PTR(err);
6538         }
6539         return em;
6540 }
6541
6542 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
6543                                                   u64 start, u64 len)
6544 {
6545         struct btrfs_root *root = BTRFS_I(inode)->root;
6546         struct extent_map *em;
6547         struct btrfs_key ins;
6548         u64 alloc_hint;
6549         int ret;
6550
6551         alloc_hint = get_extent_allocation_hint(inode, start, len);
6552         ret = btrfs_reserve_extent(root, len, root->sectorsize, 0,
6553                                    alloc_hint, &ins, 1);
6554         if (ret)
6555                 return ERR_PTR(ret);
6556
6557         em = create_pinned_em(inode, start, ins.offset, start, ins.objectid,
6558                               ins.offset, ins.offset, ins.offset, 0);
6559         if (IS_ERR(em)) {
6560                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
6561                 return em;
6562         }
6563
6564         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
6565                                            ins.offset, ins.offset, 0);
6566         if (ret) {
6567                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
6568                 free_extent_map(em);
6569                 return ERR_PTR(ret);
6570         }
6571
6572         return em;
6573 }
6574
6575 /*
6576  * returns 1 when the nocow is safe, < 1 on error, 0 if the
6577  * block must be cow'd
6578  */
6579 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
6580                               u64 *orig_start, u64 *orig_block_len,
6581                               u64 *ram_bytes)
6582 {
6583         struct btrfs_trans_handle *trans;
6584         struct btrfs_path *path;
6585         int ret;
6586         struct extent_buffer *leaf;
6587         struct btrfs_root *root = BTRFS_I(inode)->root;
6588         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6589         struct btrfs_file_extent_item *fi;
6590         struct btrfs_key key;
6591         u64 disk_bytenr;
6592         u64 backref_offset;
6593         u64 extent_end;
6594         u64 num_bytes;
6595         int slot;
6596         int found_type;
6597         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
6598
6599         path = btrfs_alloc_path();
6600         if (!path)
6601                 return -ENOMEM;
6602
6603         ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode),
6604                                        offset, 0);
6605         if (ret < 0)
6606                 goto out;
6607
6608         slot = path->slots[0];
6609         if (ret == 1) {
6610                 if (slot == 0) {
6611                         /* can't find the item, must cow */
6612                         ret = 0;
6613                         goto out;
6614                 }
6615                 slot--;
6616         }
6617         ret = 0;
6618         leaf = path->nodes[0];
6619         btrfs_item_key_to_cpu(leaf, &key, slot);
6620         if (key.objectid != btrfs_ino(inode) ||
6621             key.type != BTRFS_EXTENT_DATA_KEY) {
6622                 /* not our file or wrong item type, must cow */
6623                 goto out;
6624         }
6625
6626         if (key.offset > offset) {
6627                 /* Wrong offset, must cow */
6628                 goto out;
6629         }
6630
6631         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
6632         found_type = btrfs_file_extent_type(leaf, fi);
6633         if (found_type != BTRFS_FILE_EXTENT_REG &&
6634             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
6635                 /* not a regular extent, must cow */
6636                 goto out;
6637         }
6638
6639         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
6640                 goto out;
6641
6642         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
6643         if (extent_end <= offset)
6644                 goto out;
6645
6646         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
6647         if (disk_bytenr == 0)
6648                 goto out;
6649
6650         if (btrfs_file_extent_compression(leaf, fi) ||
6651             btrfs_file_extent_encryption(leaf, fi) ||
6652             btrfs_file_extent_other_encoding(leaf, fi))
6653                 goto out;
6654
6655         backref_offset = btrfs_file_extent_offset(leaf, fi);
6656
6657         if (orig_start) {
6658                 *orig_start = key.offset - backref_offset;
6659                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
6660                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
6661         }
6662
6663         if (btrfs_extent_readonly(root, disk_bytenr))
6664                 goto out;
6665
6666         num_bytes = min(offset + *len, extent_end) - offset;
6667         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6668                 u64 range_end;
6669
6670                 range_end = round_up(offset + num_bytes, root->sectorsize) - 1;
6671                 ret = test_range_bit(io_tree, offset, range_end,
6672                                      EXTENT_DELALLOC, 0, NULL);
6673                 if (ret) {
6674                         ret = -EAGAIN;
6675                         goto out;
6676                 }
6677         }
6678
6679         btrfs_release_path(path);
6680
6681         /*
6682          * look for other files referencing this extent, if we
6683          * find any we must cow
6684          */
6685         trans = btrfs_join_transaction(root);
6686         if (IS_ERR(trans)) {
6687                 ret = 0;
6688                 goto out;
6689         }
6690
6691         ret = btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
6692                                     key.offset - backref_offset, disk_bytenr);
6693         btrfs_end_transaction(trans, root);
6694         if (ret) {
6695                 ret = 0;
6696                 goto out;
6697         }
6698
6699         /*
6700          * adjust disk_bytenr and num_bytes to cover just the bytes
6701          * in this extent we are about to write.  If there
6702          * are any csums in that range we have to cow in order
6703          * to keep the csums correct
6704          */
6705         disk_bytenr += backref_offset;
6706         disk_bytenr += offset - key.offset;
6707         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
6708                                 goto out;
6709         /*
6710          * all of the above have passed, it is safe to overwrite this extent
6711          * without cow
6712          */
6713         *len = num_bytes;
6714         ret = 1;
6715 out:
6716         btrfs_free_path(path);
6717         return ret;
6718 }
6719
6720 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
6721                               struct extent_state **cached_state, int writing)
6722 {
6723         struct btrfs_ordered_extent *ordered;
6724         int ret = 0;
6725
6726         while (1) {
6727                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6728                                  0, cached_state);
6729                 /*
6730                  * We're concerned with the entire range that we're going to be
6731                  * doing DIO to, so we need to make sure theres no ordered
6732                  * extents in this range.
6733                  */
6734                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
6735                                                      lockend - lockstart + 1);
6736
6737                 /*
6738                  * We need to make sure there are no buffered pages in this
6739                  * range either, we could have raced between the invalidate in
6740                  * generic_file_direct_write and locking the extent.  The
6741                  * invalidate needs to happen so that reads after a write do not
6742                  * get stale data.
6743                  */
6744                 if (!ordered && (!writing ||
6745                     !test_range_bit(&BTRFS_I(inode)->io_tree,
6746                                     lockstart, lockend, EXTENT_UPTODATE, 0,
6747                                     *cached_state)))
6748                         break;
6749
6750                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6751                                      cached_state, GFP_NOFS);
6752
6753                 if (ordered) {
6754                         btrfs_start_ordered_extent(inode, ordered, 1);
6755                         btrfs_put_ordered_extent(ordered);
6756                 } else {
6757                         /* Screw you mmap */
6758                         ret = filemap_write_and_wait_range(inode->i_mapping,
6759                                                            lockstart,
6760                                                            lockend);
6761                         if (ret)
6762                                 break;
6763
6764                         /*
6765                          * If we found a page that couldn't be invalidated just
6766                          * fall back to buffered.
6767                          */
6768                         ret = invalidate_inode_pages2_range(inode->i_mapping,
6769                                         lockstart >> PAGE_CACHE_SHIFT,
6770                                         lockend >> PAGE_CACHE_SHIFT);
6771                         if (ret)
6772                                 break;
6773                 }
6774
6775                 cond_resched();
6776         }
6777
6778         return ret;
6779 }
6780
6781 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
6782                                            u64 len, u64 orig_start,
6783                                            u64 block_start, u64 block_len,
6784                                            u64 orig_block_len, u64 ram_bytes,
6785                                            int type)
6786 {
6787         struct extent_map_tree *em_tree;
6788         struct extent_map *em;
6789         struct btrfs_root *root = BTRFS_I(inode)->root;
6790         int ret;
6791
6792         em_tree = &BTRFS_I(inode)->extent_tree;
6793         em = alloc_extent_map();
6794         if (!em)
6795                 return ERR_PTR(-ENOMEM);
6796
6797         em->start = start;
6798         em->orig_start = orig_start;
6799         em->mod_start = start;
6800         em->mod_len = len;
6801         em->len = len;
6802         em->block_len = block_len;
6803         em->block_start = block_start;
6804         em->bdev = root->fs_info->fs_devices->latest_bdev;
6805         em->orig_block_len = orig_block_len;
6806         em->ram_bytes = ram_bytes;
6807         em->generation = -1;
6808         set_bit(EXTENT_FLAG_PINNED, &em->flags);
6809         if (type == BTRFS_ORDERED_PREALLOC)
6810                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
6811
6812         do {
6813                 btrfs_drop_extent_cache(inode, em->start,
6814                                 em->start + em->len - 1, 0);
6815                 write_lock(&em_tree->lock);
6816                 ret = add_extent_mapping(em_tree, em, 1);
6817                 write_unlock(&em_tree->lock);
6818         } while (ret == -EEXIST);
6819
6820         if (ret) {
6821                 free_extent_map(em);
6822                 return ERR_PTR(ret);
6823         }
6824
6825         return em;
6826 }
6827
6828
6829 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
6830                                    struct buffer_head *bh_result, int create)
6831 {
6832         struct extent_map *em;
6833         struct btrfs_root *root = BTRFS_I(inode)->root;
6834         struct extent_state *cached_state = NULL;
6835         u64 start = iblock << inode->i_blkbits;
6836         u64 lockstart, lockend;
6837         u64 len = bh_result->b_size;
6838         int unlock_bits = EXTENT_LOCKED;
6839         int ret = 0;
6840
6841         if (create)
6842                 unlock_bits |= EXTENT_DELALLOC | EXTENT_DIRTY;
6843         else
6844                 len = min_t(u64, len, root->sectorsize);
6845
6846         lockstart = start;
6847         lockend = start + len - 1;
6848
6849         /*
6850          * If this errors out it's because we couldn't invalidate pagecache for
6851          * this range and we need to fallback to buffered.
6852          */
6853         if (lock_extent_direct(inode, lockstart, lockend, &cached_state, create))
6854                 return -ENOTBLK;
6855
6856         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
6857         if (IS_ERR(em)) {
6858                 ret = PTR_ERR(em);
6859                 goto unlock_err;
6860         }
6861
6862         /*
6863          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
6864          * io.  INLINE is special, and we could probably kludge it in here, but
6865          * it's still buffered so for safety lets just fall back to the generic
6866          * buffered path.
6867          *
6868          * For COMPRESSED we _have_ to read the entire extent in so we can
6869          * decompress it, so there will be buffering required no matter what we
6870          * do, so go ahead and fallback to buffered.
6871          *
6872          * We return -ENOTBLK because thats what makes DIO go ahead and go back
6873          * to buffered IO.  Don't blame me, this is the price we pay for using
6874          * the generic code.
6875          */
6876         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
6877             em->block_start == EXTENT_MAP_INLINE) {
6878                 free_extent_map(em);
6879                 ret = -ENOTBLK;
6880                 goto unlock_err;
6881         }
6882
6883         /* Just a good old fashioned hole, return */
6884         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
6885                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
6886                 free_extent_map(em);
6887                 goto unlock_err;
6888         }
6889
6890         /*
6891          * We don't allocate a new extent in the following cases
6892          *
6893          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
6894          * existing extent.
6895          * 2) The extent is marked as PREALLOC.  We're good to go here and can
6896          * just use the extent.
6897          *
6898          */
6899         if (!create) {
6900                 len = min(len, em->len - (start - em->start));
6901                 lockstart = start + len;
6902                 goto unlock;
6903         }
6904
6905         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
6906             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
6907              em->block_start != EXTENT_MAP_HOLE)) {
6908                 int type;
6909                 int ret;
6910                 u64 block_start, orig_start, orig_block_len, ram_bytes;
6911
6912                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6913                         type = BTRFS_ORDERED_PREALLOC;
6914                 else
6915                         type = BTRFS_ORDERED_NOCOW;
6916                 len = min(len, em->len - (start - em->start));
6917                 block_start = em->block_start + (start - em->start);
6918
6919                 if (can_nocow_extent(inode, start, &len, &orig_start,
6920                                      &orig_block_len, &ram_bytes) == 1) {
6921                         if (type == BTRFS_ORDERED_PREALLOC) {
6922                                 free_extent_map(em);
6923                                 em = create_pinned_em(inode, start, len,
6924                                                        orig_start,
6925                                                        block_start, len,
6926                                                        orig_block_len,
6927                                                        ram_bytes, type);
6928                                 if (IS_ERR(em))
6929                                         goto unlock_err;
6930                         }
6931
6932                         ret = btrfs_add_ordered_extent_dio(inode, start,
6933                                            block_start, len, len, type);
6934                         if (ret) {
6935                                 free_extent_map(em);
6936                                 goto unlock_err;
6937                         }
6938                         goto unlock;
6939                 }
6940         }
6941
6942         /*
6943          * this will cow the extent, reset the len in case we changed
6944          * it above
6945          */
6946         len = bh_result->b_size;
6947         free_extent_map(em);
6948         em = btrfs_new_extent_direct(inode, start, len);
6949         if (IS_ERR(em)) {
6950                 ret = PTR_ERR(em);
6951                 goto unlock_err;
6952         }
6953         len = min(len, em->len - (start - em->start));
6954 unlock:
6955         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
6956                 inode->i_blkbits;
6957         bh_result->b_size = len;
6958         bh_result->b_bdev = em->bdev;
6959         set_buffer_mapped(bh_result);
6960         if (create) {
6961                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6962                         set_buffer_new(bh_result);
6963
6964                 /*
6965                  * Need to update the i_size under the extent lock so buffered
6966                  * readers will get the updated i_size when we unlock.
6967                  */
6968                 if (start + len > i_size_read(inode))
6969                         i_size_write(inode, start + len);
6970
6971                 spin_lock(&BTRFS_I(inode)->lock);
6972                 BTRFS_I(inode)->outstanding_extents++;
6973                 spin_unlock(&BTRFS_I(inode)->lock);
6974
6975                 ret = set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
6976                                      lockstart + len - 1, EXTENT_DELALLOC, NULL,
6977                                      &cached_state, GFP_NOFS);
6978                 BUG_ON(ret);
6979         }
6980
6981         /*
6982          * In the case of write we need to clear and unlock the entire range,
6983          * in the case of read we need to unlock only the end area that we
6984          * aren't using if there is any left over space.
6985          */
6986         if (lockstart < lockend) {
6987                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
6988                                  lockend, unlock_bits, 1, 0,
6989                                  &cached_state, GFP_NOFS);
6990         } else {
6991                 free_extent_state(cached_state);
6992         }
6993
6994         free_extent_map(em);
6995
6996         return 0;
6997
6998 unlock_err:
6999         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7000                          unlock_bits, 1, 0, &cached_state, GFP_NOFS);
7001         return ret;
7002 }
7003
7004 static void btrfs_endio_direct_read(struct bio *bio, int err)
7005 {
7006         struct btrfs_dio_private *dip = bio->bi_private;
7007         struct bio_vec *bvec;
7008         struct inode *inode = dip->inode;
7009         struct btrfs_root *root = BTRFS_I(inode)->root;
7010         struct bio *dio_bio;
7011         u32 *csums = (u32 *)dip->csum;
7012         u64 start;
7013         int i;
7014
7015         start = dip->logical_offset;
7016         bio_for_each_segment_all(bvec, bio, i) {
7017                 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
7018                         struct page *page = bvec->bv_page;
7019                         char *kaddr;
7020                         u32 csum = ~(u32)0;
7021                         unsigned long flags;
7022
7023                         local_irq_save(flags);
7024                         kaddr = kmap_atomic(page);
7025                         csum = btrfs_csum_data(kaddr + bvec->bv_offset,
7026                                                csum, bvec->bv_len);
7027                         btrfs_csum_final(csum, (char *)&csum);
7028                         kunmap_atomic(kaddr);
7029                         local_irq_restore(flags);
7030
7031                         flush_dcache_page(bvec->bv_page);
7032                         if (csum != csums[i]) {
7033                                 btrfs_err(root->fs_info, "csum failed ino %llu off %llu csum %u expected csum %u",
7034                                           btrfs_ino(inode), start, csum,
7035                                           csums[i]);
7036                                 err = -EIO;
7037                         }
7038                 }
7039
7040                 start += bvec->bv_len;
7041         }
7042
7043         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
7044                       dip->logical_offset + dip->bytes - 1);
7045         dio_bio = dip->dio_bio;
7046
7047         kfree(dip);
7048
7049         /* If we had a csum failure make sure to clear the uptodate flag */
7050         if (err)
7051                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7052         dio_end_io(dio_bio, err);
7053         bio_put(bio);
7054 }
7055
7056 static void btrfs_endio_direct_write(struct bio *bio, int err)
7057 {
7058         struct btrfs_dio_private *dip = bio->bi_private;
7059         struct inode *inode = dip->inode;
7060         struct btrfs_root *root = BTRFS_I(inode)->root;
7061         struct btrfs_ordered_extent *ordered = NULL;
7062         u64 ordered_offset = dip->logical_offset;
7063         u64 ordered_bytes = dip->bytes;
7064         struct bio *dio_bio;
7065         int ret;
7066
7067         if (err)
7068                 goto out_done;
7069 again:
7070         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
7071                                                    &ordered_offset,
7072                                                    ordered_bytes, !err);
7073         if (!ret)
7074                 goto out_test;
7075
7076         btrfs_init_work(&ordered->work, finish_ordered_fn, NULL, NULL);
7077         btrfs_queue_work(root->fs_info->endio_write_workers,
7078                          &ordered->work);
7079 out_test:
7080         /*
7081          * our bio might span multiple ordered extents.  If we haven't
7082          * completed the accounting for the whole dio, go back and try again
7083          */
7084         if (ordered_offset < dip->logical_offset + dip->bytes) {
7085                 ordered_bytes = dip->logical_offset + dip->bytes -
7086                         ordered_offset;
7087                 ordered = NULL;
7088                 goto again;
7089         }
7090 out_done:
7091         dio_bio = dip->dio_bio;
7092
7093         kfree(dip);
7094
7095         /* If we had an error make sure to clear the uptodate flag */
7096         if (err)
7097                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7098         dio_end_io(dio_bio, err);
7099         bio_put(bio);
7100 }
7101
7102 static int __btrfs_submit_bio_start_direct_io(struct inode *inode, int rw,
7103                                     struct bio *bio, int mirror_num,
7104                                     unsigned long bio_flags, u64 offset)
7105 {
7106         int ret;
7107         struct btrfs_root *root = BTRFS_I(inode)->root;
7108         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
7109         BUG_ON(ret); /* -ENOMEM */
7110         return 0;
7111 }
7112
7113 static void btrfs_end_dio_bio(struct bio *bio, int err)
7114 {
7115         struct btrfs_dio_private *dip = bio->bi_private;
7116
7117         if (err) {
7118                 btrfs_err(BTRFS_I(dip->inode)->root->fs_info,
7119                           "direct IO failed ino %llu rw %lu sector %#Lx len %u err no %d",
7120                       btrfs_ino(dip->inode), bio->bi_rw,
7121                       (unsigned long long)bio->bi_iter.bi_sector,
7122                       bio->bi_iter.bi_size, err);
7123                 dip->errors = 1;
7124
7125                 /*
7126                  * before atomic variable goto zero, we must make sure
7127                  * dip->errors is perceived to be set.
7128                  */
7129                 smp_mb__before_atomic();
7130         }
7131
7132         /* if there are more bios still pending for this dio, just exit */
7133         if (!atomic_dec_and_test(&dip->pending_bios))
7134                 goto out;
7135
7136         if (dip->errors) {
7137                 bio_io_error(dip->orig_bio);
7138         } else {
7139                 set_bit(BIO_UPTODATE, &dip->dio_bio->bi_flags);
7140                 bio_endio(dip->orig_bio, 0);
7141         }
7142 out:
7143         bio_put(bio);
7144 }
7145
7146 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
7147                                        u64 first_sector, gfp_t gfp_flags)
7148 {
7149         int nr_vecs = bio_get_nr_vecs(bdev);
7150         return btrfs_bio_alloc(bdev, first_sector, nr_vecs, gfp_flags);
7151 }
7152
7153 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
7154                                          int rw, u64 file_offset, int skip_sum,
7155                                          int async_submit)
7156 {
7157         struct btrfs_dio_private *dip = bio->bi_private;
7158         int write = rw & REQ_WRITE;
7159         struct btrfs_root *root = BTRFS_I(inode)->root;
7160         int ret;
7161
7162         if (async_submit)
7163                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
7164
7165         bio_get(bio);
7166
7167         if (!write) {
7168                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
7169                 if (ret)
7170                         goto err;
7171         }
7172
7173         if (skip_sum)
7174                 goto map;
7175
7176         if (write && async_submit) {
7177                 ret = btrfs_wq_submit_bio(root->fs_info,
7178                                    inode, rw, bio, 0, 0,
7179                                    file_offset,
7180                                    __btrfs_submit_bio_start_direct_io,
7181                                    __btrfs_submit_bio_done);
7182                 goto err;
7183         } else if (write) {
7184                 /*
7185                  * If we aren't doing async submit, calculate the csum of the
7186                  * bio now.
7187                  */
7188                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
7189                 if (ret)
7190                         goto err;
7191         } else if (!skip_sum) {
7192                 ret = btrfs_lookup_bio_sums_dio(root, inode, dip, bio,
7193                                                 file_offset);
7194                 if (ret)
7195                         goto err;
7196         }
7197
7198 map:
7199         ret = btrfs_map_bio(root, rw, bio, 0, async_submit);
7200 err:
7201         bio_put(bio);
7202         return ret;
7203 }
7204
7205 static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
7206                                     int skip_sum)
7207 {
7208         struct inode *inode = dip->inode;
7209         struct btrfs_root *root = BTRFS_I(inode)->root;
7210         struct bio *bio;
7211         struct bio *orig_bio = dip->orig_bio;
7212         struct bio_vec *bvec = orig_bio->bi_io_vec;
7213         u64 start_sector = orig_bio->bi_iter.bi_sector;
7214         u64 file_offset = dip->logical_offset;
7215         u64 submit_len = 0;
7216         u64 map_length;
7217         int nr_pages = 0;
7218         int ret = 0;
7219         int async_submit = 0;
7220
7221         map_length = orig_bio->bi_iter.bi_size;
7222         ret = btrfs_map_block(root->fs_info, rw, start_sector << 9,
7223                               &map_length, NULL, 0);
7224         if (ret) {
7225                 bio_put(orig_bio);
7226                 return -EIO;
7227         }
7228
7229         if (map_length >= orig_bio->bi_iter.bi_size) {
7230                 bio = orig_bio;
7231                 goto submit;
7232         }
7233
7234         /* async crcs make it difficult to collect full stripe writes. */
7235         if (btrfs_get_alloc_profile(root, 1) &
7236             (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6))
7237                 async_submit = 0;
7238         else
7239                 async_submit = 1;
7240
7241         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
7242         if (!bio)
7243                 return -ENOMEM;
7244         bio->bi_private = dip;
7245         bio->bi_end_io = btrfs_end_dio_bio;
7246         atomic_inc(&dip->pending_bios);
7247
7248         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
7249                 if (unlikely(map_length < submit_len + bvec->bv_len ||
7250                     bio_add_page(bio, bvec->bv_page, bvec->bv_len,
7251                                  bvec->bv_offset) < bvec->bv_len)) {
7252                         /*
7253                          * inc the count before we submit the bio so
7254                          * we know the end IO handler won't happen before
7255                          * we inc the count. Otherwise, the dip might get freed
7256                          * before we're done setting it up
7257                          */
7258                         atomic_inc(&dip->pending_bios);
7259                         ret = __btrfs_submit_dio_bio(bio, inode, rw,
7260                                                      file_offset, skip_sum,
7261                                                      async_submit);
7262                         if (ret) {
7263                                 bio_put(bio);
7264                                 atomic_dec(&dip->pending_bios);
7265                                 goto out_err;
7266                         }
7267
7268                         start_sector += submit_len >> 9;
7269                         file_offset += submit_len;
7270
7271                         submit_len = 0;
7272                         nr_pages = 0;
7273
7274                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
7275                                                   start_sector, GFP_NOFS);
7276                         if (!bio)
7277                                 goto out_err;
7278                         bio->bi_private = dip;
7279                         bio->bi_end_io = btrfs_end_dio_bio;
7280
7281                         map_length = orig_bio->bi_iter.bi_size;
7282                         ret = btrfs_map_block(root->fs_info, rw,
7283                                               start_sector << 9,
7284                                               &map_length, NULL, 0);
7285                         if (ret) {
7286                                 bio_put(bio);
7287                                 goto out_err;
7288                         }
7289                 } else {
7290                         submit_len += bvec->bv_len;
7291                         nr_pages++;
7292                         bvec++;
7293                 }
7294         }
7295
7296 submit:
7297         ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum,
7298                                      async_submit);
7299         if (!ret)
7300                 return 0;
7301
7302         bio_put(bio);
7303 out_err:
7304         dip->errors = 1;
7305         /*
7306          * before atomic variable goto zero, we must
7307          * make sure dip->errors is perceived to be set.
7308          */
7309         smp_mb__before_atomic();
7310         if (atomic_dec_and_test(&dip->pending_bios))
7311                 bio_io_error(dip->orig_bio);
7312
7313         /* bio_end_io() will handle error, so we needn't return it */
7314         return 0;
7315 }
7316
7317 static void btrfs_submit_direct(int rw, struct bio *dio_bio,
7318                                 struct inode *inode, loff_t file_offset)
7319 {
7320         struct btrfs_root *root = BTRFS_I(inode)->root;
7321         struct btrfs_dio_private *dip;
7322         struct bio *io_bio;
7323         int skip_sum;
7324         int sum_len;
7325         int write = rw & REQ_WRITE;
7326         int ret = 0;
7327         u16 csum_size;
7328
7329         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
7330
7331         io_bio = btrfs_bio_clone(dio_bio, GFP_NOFS);
7332         if (!io_bio) {
7333                 ret = -ENOMEM;
7334                 goto free_ordered;
7335         }
7336
7337         if (!skip_sum && !write) {
7338                 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
7339                 sum_len = dio_bio->bi_iter.bi_size >>
7340                         inode->i_sb->s_blocksize_bits;
7341                 sum_len *= csum_size;
7342         } else {
7343                 sum_len = 0;
7344         }
7345
7346         dip = kmalloc(sizeof(*dip) + sum_len, GFP_NOFS);
7347         if (!dip) {
7348                 ret = -ENOMEM;
7349                 goto free_io_bio;
7350         }
7351
7352         dip->private = dio_bio->bi_private;
7353         dip->inode = inode;
7354         dip->logical_offset = file_offset;
7355         dip->bytes = dio_bio->bi_iter.bi_size;
7356         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
7357         io_bio->bi_private = dip;
7358         dip->errors = 0;
7359         dip->orig_bio = io_bio;
7360         dip->dio_bio = dio_bio;
7361         atomic_set(&dip->pending_bios, 0);
7362
7363         if (write)
7364                 io_bio->bi_end_io = btrfs_endio_direct_write;
7365         else
7366                 io_bio->bi_end_io = btrfs_endio_direct_read;
7367
7368         ret = btrfs_submit_direct_hook(rw, dip, skip_sum);
7369         if (!ret)
7370                 return;
7371
7372 free_io_bio:
7373         bio_put(io_bio);
7374
7375 free_ordered:
7376         /*
7377          * If this is a write, we need to clean up the reserved space and kill
7378          * the ordered extent.
7379          */
7380         if (write) {
7381                 struct btrfs_ordered_extent *ordered;
7382                 ordered = btrfs_lookup_ordered_extent(inode, file_offset);
7383                 if (!test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags) &&
7384                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags))
7385                         btrfs_free_reserved_extent(root, ordered->start,
7386                                                    ordered->disk_len);
7387                 btrfs_put_ordered_extent(ordered);
7388                 btrfs_put_ordered_extent(ordered);
7389         }
7390         bio_endio(dio_bio, ret);
7391 }
7392
7393 static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *iocb,
7394                         const struct iovec *iov, loff_t offset,
7395                         unsigned long nr_segs)
7396 {
7397         int seg;
7398         int i;
7399         size_t size;
7400         unsigned long addr;
7401         unsigned blocksize_mask = root->sectorsize - 1;
7402         ssize_t retval = -EINVAL;
7403         loff_t end = offset;
7404
7405         if (offset & blocksize_mask)
7406                 goto out;
7407
7408         /* Check the memory alignment.  Blocks cannot straddle pages */
7409         for (seg = 0; seg < nr_segs; seg++) {
7410                 addr = (unsigned long)iov[seg].iov_base;
7411                 size = iov[seg].iov_len;
7412                 end += size;
7413                 if ((addr & blocksize_mask) || (size & blocksize_mask))
7414                         goto out;
7415
7416                 /* If this is a write we don't need to check anymore */
7417                 if (rw & WRITE)
7418                         continue;
7419
7420                 /*
7421                  * Check to make sure we don't have duplicate iov_base's in this
7422                  * iovec, if so return EINVAL, otherwise we'll get csum errors
7423                  * when reading back.
7424                  */
7425                 for (i = seg + 1; i < nr_segs; i++) {
7426                         if (iov[seg].iov_base == iov[i].iov_base)
7427                                 goto out;
7428                 }
7429         }
7430         retval = 0;
7431 out:
7432         return retval;
7433 }
7434
7435 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
7436                         const struct iovec *iov, loff_t offset,
7437                         unsigned long nr_segs)
7438 {
7439         struct file *file = iocb->ki_filp;
7440         struct inode *inode = file->f_mapping->host;
7441         size_t count = 0;
7442         int flags = 0;
7443         bool wakeup = true;
7444         bool relock = false;
7445         ssize_t ret;
7446
7447         if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iov,
7448                             offset, nr_segs))
7449                 return 0;
7450
7451         atomic_inc(&inode->i_dio_count);
7452         smp_mb__after_atomic();
7453
7454         /*
7455          * The generic stuff only does filemap_write_and_wait_range, which
7456          * isn't enough if we've written compressed pages to this area, so
7457          * we need to flush the dirty pages again to make absolutely sure
7458          * that any outstanding dirty pages are on disk.
7459          */
7460         count = iov_length(iov, nr_segs);
7461         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
7462                      &BTRFS_I(inode)->runtime_flags))
7463                 filemap_fdatawrite_range(inode->i_mapping, offset, count);
7464
7465         if (rw & WRITE) {
7466                 /*
7467                  * If the write DIO is beyond the EOF, we need update
7468                  * the isize, but it is protected by i_mutex. So we can
7469                  * not unlock the i_mutex at this case.
7470                  */
7471                 if (offset + count <= inode->i_size) {
7472                         mutex_unlock(&inode->i_mutex);
7473                         relock = true;
7474                 }
7475                 ret = btrfs_delalloc_reserve_space(inode, count);
7476                 if (ret)
7477                         goto out;
7478         } else if (unlikely(test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
7479                                      &BTRFS_I(inode)->runtime_flags))) {
7480                 inode_dio_done(inode);
7481                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
7482                 wakeup = false;
7483         }
7484
7485         ret = __blockdev_direct_IO(rw, iocb, inode,
7486                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
7487                         iov, offset, nr_segs, btrfs_get_blocks_direct, NULL,
7488                         btrfs_submit_direct, flags);
7489         if (rw & WRITE) {
7490                 if (ret < 0 && ret != -EIOCBQUEUED)
7491                         btrfs_delalloc_release_space(inode, count);
7492                 else if (ret >= 0 && (size_t)ret < count)
7493                         btrfs_delalloc_release_space(inode,
7494                                                      count - (size_t)ret);
7495                 else
7496                         btrfs_delalloc_release_metadata(inode, 0);
7497         }
7498 out:
7499         if (wakeup)
7500                 inode_dio_done(inode);
7501         if (relock)
7502                 mutex_lock(&inode->i_mutex);
7503
7504         return ret;
7505 }
7506
7507 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
7508
7509 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
7510                 __u64 start, __u64 len)
7511 {
7512         int     ret;
7513
7514         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
7515         if (ret)
7516                 return ret;
7517
7518         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
7519 }
7520
7521 int btrfs_readpage(struct file *file, struct page *page)
7522 {
7523         struct extent_io_tree *tree;
7524         tree = &BTRFS_I(page->mapping->host)->io_tree;
7525         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
7526 }
7527
7528 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
7529 {
7530         struct extent_io_tree *tree;
7531
7532
7533         if (current->flags & PF_MEMALLOC) {
7534                 redirty_page_for_writepage(wbc, page);
7535                 unlock_page(page);
7536                 return 0;
7537         }
7538         tree = &BTRFS_I(page->mapping->host)->io_tree;
7539         return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
7540 }
7541
7542 static int btrfs_writepages(struct address_space *mapping,
7543                             struct writeback_control *wbc)
7544 {
7545         struct extent_io_tree *tree;
7546
7547         tree = &BTRFS_I(mapping->host)->io_tree;
7548         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
7549 }
7550
7551 static int
7552 btrfs_readpages(struct file *file, struct address_space *mapping,
7553                 struct list_head *pages, unsigned nr_pages)
7554 {
7555         struct extent_io_tree *tree;
7556         tree = &BTRFS_I(mapping->host)->io_tree;
7557         return extent_readpages(tree, mapping, pages, nr_pages,
7558                                 btrfs_get_extent);
7559 }
7560 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
7561 {
7562         struct extent_io_tree *tree;
7563         struct extent_map_tree *map;
7564         int ret;
7565
7566         tree = &BTRFS_I(page->mapping->host)->io_tree;
7567         map = &BTRFS_I(page->mapping->host)->extent_tree;
7568         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
7569         if (ret == 1) {
7570                 ClearPagePrivate(page);
7571                 set_page_private(page, 0);
7572                 page_cache_release(page);
7573         }
7574         return ret;
7575 }
7576
7577 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
7578 {
7579         if (PageWriteback(page) || PageDirty(page))
7580                 return 0;
7581         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
7582 }
7583
7584 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
7585                                  unsigned int length)
7586 {
7587         struct inode *inode = page->mapping->host;
7588         struct extent_io_tree *tree;
7589         struct btrfs_ordered_extent *ordered;
7590         struct extent_state *cached_state = NULL;
7591         u64 page_start = page_offset(page);
7592         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
7593         int inode_evicting = inode->i_state & I_FREEING;
7594
7595         /*
7596          * we have the page locked, so new writeback can't start,
7597          * and the dirty bit won't be cleared while we are here.
7598          *
7599          * Wait for IO on this page so that we can safely clear
7600          * the PagePrivate2 bit and do ordered accounting
7601          */
7602         wait_on_page_writeback(page);
7603
7604         tree = &BTRFS_I(inode)->io_tree;
7605         if (offset) {
7606                 btrfs_releasepage(page, GFP_NOFS);
7607                 return;
7608         }
7609
7610         if (!inode_evicting)
7611                 lock_extent_bits(tree, page_start, page_end, 0, &cached_state);
7612         ordered = btrfs_lookup_ordered_extent(inode, page_start);
7613         if (ordered) {
7614                 /*
7615                  * IO on this page will never be started, so we need
7616                  * to account for any ordered extents now
7617                  */
7618                 if (!inode_evicting)
7619                         clear_extent_bit(tree, page_start, page_end,
7620                                          EXTENT_DIRTY | EXTENT_DELALLOC |
7621                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
7622                                          EXTENT_DEFRAG, 1, 0, &cached_state,
7623                                          GFP_NOFS);
7624                 /*
7625                  * whoever cleared the private bit is responsible
7626                  * for the finish_ordered_io
7627                  */
7628                 if (TestClearPagePrivate2(page)) {
7629                         struct btrfs_ordered_inode_tree *tree;
7630                         u64 new_len;
7631
7632                         tree = &BTRFS_I(inode)->ordered_tree;
7633
7634                         spin_lock_irq(&tree->lock);
7635                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
7636                         new_len = page_start - ordered->file_offset;
7637                         if (new_len < ordered->truncated_len)
7638                                 ordered->truncated_len = new_len;
7639                         spin_unlock_irq(&tree->lock);
7640
7641                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
7642                                                            page_start,
7643                                                            PAGE_CACHE_SIZE, 1))
7644                                 btrfs_finish_ordered_io(ordered);
7645                 }
7646                 btrfs_put_ordered_extent(ordered);
7647                 if (!inode_evicting) {
7648                         cached_state = NULL;
7649                         lock_extent_bits(tree, page_start, page_end, 0,
7650                                          &cached_state);
7651                 }
7652         }
7653
7654         if (!inode_evicting) {
7655                 clear_extent_bit(tree, page_start, page_end,
7656                                  EXTENT_LOCKED | EXTENT_DIRTY |
7657                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
7658                                  EXTENT_DEFRAG, 1, 1,
7659                                  &cached_state, GFP_NOFS);
7660
7661                 __btrfs_releasepage(page, GFP_NOFS);
7662         }
7663
7664         ClearPageChecked(page);
7665         if (PagePrivate(page)) {
7666                 ClearPagePrivate(page);
7667                 set_page_private(page, 0);
7668                 page_cache_release(page);
7669         }
7670 }
7671
7672 /*
7673  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
7674  * called from a page fault handler when a page is first dirtied. Hence we must
7675  * be careful to check for EOF conditions here. We set the page up correctly
7676  * for a written page which means we get ENOSPC checking when writing into
7677  * holes and correct delalloc and unwritten extent mapping on filesystems that
7678  * support these features.
7679  *
7680  * We are not allowed to take the i_mutex here so we have to play games to
7681  * protect against truncate races as the page could now be beyond EOF.  Because
7682  * vmtruncate() writes the inode size before removing pages, once we have the
7683  * page lock we can determine safely if the page is beyond EOF. If it is not
7684  * beyond EOF, then the page is guaranteed safe against truncation until we
7685  * unlock the page.
7686  */
7687 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
7688 {
7689         struct page *page = vmf->page;
7690         struct inode *inode = file_inode(vma->vm_file);
7691         struct btrfs_root *root = BTRFS_I(inode)->root;
7692         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7693         struct btrfs_ordered_extent *ordered;
7694         struct extent_state *cached_state = NULL;
7695         char *kaddr;
7696         unsigned long zero_start;
7697         loff_t size;
7698         int ret;
7699         int reserved = 0;
7700         u64 page_start;
7701         u64 page_end;
7702
7703         sb_start_pagefault(inode->i_sb);
7704         ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
7705         if (!ret) {
7706                 ret = file_update_time(vma->vm_file);
7707                 reserved = 1;
7708         }
7709         if (ret) {
7710                 if (ret == -ENOMEM)
7711                         ret = VM_FAULT_OOM;
7712                 else /* -ENOSPC, -EIO, etc */
7713                         ret = VM_FAULT_SIGBUS;
7714                 if (reserved)
7715                         goto out;
7716                 goto out_noreserve;
7717         }
7718
7719         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
7720 again:
7721         lock_page(page);
7722         size = i_size_read(inode);
7723         page_start = page_offset(page);
7724         page_end = page_start + PAGE_CACHE_SIZE - 1;
7725
7726         if ((page->mapping != inode->i_mapping) ||
7727             (page_start >= size)) {
7728                 /* page got truncated out from underneath us */
7729                 goto out_unlock;
7730         }
7731         wait_on_page_writeback(page);
7732
7733         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
7734         set_page_extent_mapped(page);
7735
7736         /*
7737          * we can't set the delalloc bits if there are pending ordered
7738          * extents.  Drop our locks and wait for them to finish
7739          */
7740         ordered = btrfs_lookup_ordered_extent(inode, page_start);
7741         if (ordered) {
7742                 unlock_extent_cached(io_tree, page_start, page_end,
7743                                      &cached_state, GFP_NOFS);
7744                 unlock_page(page);
7745                 btrfs_start_ordered_extent(inode, ordered, 1);
7746                 btrfs_put_ordered_extent(ordered);
7747                 goto again;
7748         }
7749
7750         /*
7751          * XXX - page_mkwrite gets called every time the page is dirtied, even
7752          * if it was already dirty, so for space accounting reasons we need to
7753          * clear any delalloc bits for the range we are fixing to save.  There
7754          * is probably a better way to do this, but for now keep consistent with
7755          * prepare_pages in the normal write path.
7756          */
7757         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
7758                           EXTENT_DIRTY | EXTENT_DELALLOC |
7759                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
7760                           0, 0, &cached_state, GFP_NOFS);
7761
7762         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
7763                                         &cached_state);
7764         if (ret) {
7765                 unlock_extent_cached(io_tree, page_start, page_end,
7766                                      &cached_state, GFP_NOFS);
7767                 ret = VM_FAULT_SIGBUS;
7768                 goto out_unlock;
7769         }
7770         ret = 0;
7771
7772         /* page is wholly or partially inside EOF */
7773         if (page_start + PAGE_CACHE_SIZE > size)
7774                 zero_start = size & ~PAGE_CACHE_MASK;
7775         else
7776                 zero_start = PAGE_CACHE_SIZE;
7777
7778         if (zero_start != PAGE_CACHE_SIZE) {
7779                 kaddr = kmap(page);
7780                 memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
7781                 flush_dcache_page(page);
7782                 kunmap(page);
7783         }
7784         ClearPageChecked(page);
7785         set_page_dirty(page);
7786         SetPageUptodate(page);
7787
7788         BTRFS_I(inode)->last_trans = root->fs_info->generation;
7789         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
7790         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
7791
7792         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
7793
7794 out_unlock:
7795         if (!ret) {
7796                 sb_end_pagefault(inode->i_sb);
7797                 return VM_FAULT_LOCKED;
7798         }
7799         unlock_page(page);
7800 out:
7801         btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
7802 out_noreserve:
7803         sb_end_pagefault(inode->i_sb);
7804         return ret;
7805 }
7806
7807 static int btrfs_truncate(struct inode *inode)
7808 {
7809         struct btrfs_root *root = BTRFS_I(inode)->root;
7810         struct btrfs_block_rsv *rsv;
7811         int ret = 0;
7812         int err = 0;
7813         struct btrfs_trans_handle *trans;
7814         u64 mask = root->sectorsize - 1;
7815         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
7816
7817         ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
7818                                        (u64)-1);
7819         if (ret)
7820                 return ret;
7821
7822         /*
7823          * Yes ladies and gentelment, this is indeed ugly.  The fact is we have
7824          * 3 things going on here
7825          *
7826          * 1) We need to reserve space for our orphan item and the space to
7827          * delete our orphan item.  Lord knows we don't want to have a dangling
7828          * orphan item because we didn't reserve space to remove it.
7829          *
7830          * 2) We need to reserve space to update our inode.
7831          *
7832          * 3) We need to have something to cache all the space that is going to
7833          * be free'd up by the truncate operation, but also have some slack
7834          * space reserved in case it uses space during the truncate (thank you
7835          * very much snapshotting).
7836          *
7837          * And we need these to all be seperate.  The fact is we can use alot of
7838          * space doing the truncate, and we have no earthly idea how much space
7839          * we will use, so we need the truncate reservation to be seperate so it
7840          * doesn't end up using space reserved for updating the inode or
7841          * removing the orphan item.  We also need to be able to stop the
7842          * transaction and start a new one, which means we need to be able to
7843          * update the inode several times, and we have no idea of knowing how
7844          * many times that will be, so we can't just reserve 1 item for the
7845          * entirety of the opration, so that has to be done seperately as well.
7846          * Then there is the orphan item, which does indeed need to be held on
7847          * to for the whole operation, and we need nobody to touch this reserved
7848          * space except the orphan code.
7849          *
7850          * So that leaves us with
7851          *
7852          * 1) root->orphan_block_rsv - for the orphan deletion.
7853          * 2) rsv - for the truncate reservation, which we will steal from the
7854          * transaction reservation.
7855          * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
7856          * updating the inode.
7857          */
7858         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
7859         if (!rsv)
7860                 return -ENOMEM;
7861         rsv->size = min_size;
7862         rsv->failfast = 1;
7863
7864         /*
7865          * 1 for the truncate slack space
7866          * 1 for updating the inode.
7867          */
7868         trans = btrfs_start_transaction(root, 2);
7869         if (IS_ERR(trans)) {
7870                 err = PTR_ERR(trans);
7871                 goto out;
7872         }
7873
7874         /* Migrate the slack space for the truncate to our reserve */
7875         ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
7876                                       min_size);
7877         BUG_ON(ret);
7878
7879         /*
7880          * setattr is responsible for setting the ordered_data_close flag,
7881          * but that is only tested during the last file release.  That
7882          * could happen well after the next commit, leaving a great big
7883          * window where new writes may get lost if someone chooses to write
7884          * to this file after truncating to zero
7885          *
7886          * The inode doesn't have any dirty data here, and so if we commit
7887          * this is a noop.  If someone immediately starts writing to the inode
7888          * it is very likely we'll catch some of their writes in this
7889          * transaction, and the commit will find this file on the ordered
7890          * data list with good things to send down.
7891          *
7892          * This is a best effort solution, there is still a window where
7893          * using truncate to replace the contents of the file will
7894          * end up with a zero length file after a crash.
7895          */
7896         if (inode->i_size == 0 && test_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
7897                                            &BTRFS_I(inode)->runtime_flags))
7898                 btrfs_add_ordered_operation(trans, root, inode);
7899
7900         /*
7901          * So if we truncate and then write and fsync we normally would just
7902          * write the extents that changed, which is a problem if we need to
7903          * first truncate that entire inode.  So set this flag so we write out
7904          * all of the extents in the inode to the sync log so we're completely
7905          * safe.
7906          */
7907         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
7908         trans->block_rsv = rsv;
7909
7910         while (1) {
7911                 ret = btrfs_truncate_inode_items(trans, root, inode,
7912                                                  inode->i_size,
7913                                                  BTRFS_EXTENT_DATA_KEY);
7914                 if (ret != -ENOSPC) {
7915                         err = ret;
7916                         break;
7917                 }
7918
7919                 trans->block_rsv = &root->fs_info->trans_block_rsv;
7920                 ret = btrfs_update_inode(trans, root, inode);
7921                 if (ret) {
7922                         err = ret;
7923                         break;
7924                 }
7925
7926                 btrfs_end_transaction(trans, root);
7927                 btrfs_btree_balance_dirty(root);
7928
7929                 trans = btrfs_start_transaction(root, 2);
7930                 if (IS_ERR(trans)) {
7931                         ret = err = PTR_ERR(trans);
7932                         trans = NULL;
7933                         break;
7934                 }
7935
7936                 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
7937                                               rsv, min_size);
7938                 BUG_ON(ret);    /* shouldn't happen */
7939                 trans->block_rsv = rsv;
7940         }
7941
7942         if (ret == 0 && inode->i_nlink > 0) {
7943                 trans->block_rsv = root->orphan_block_rsv;
7944                 ret = btrfs_orphan_del(trans, inode);
7945                 if (ret)
7946                         err = ret;
7947         }
7948
7949         if (trans) {
7950                 trans->block_rsv = &root->fs_info->trans_block_rsv;
7951                 ret = btrfs_update_inode(trans, root, inode);
7952                 if (ret && !err)
7953                         err = ret;
7954
7955                 ret = btrfs_end_transaction(trans, root);
7956                 btrfs_btree_balance_dirty(root);
7957         }
7958
7959 out:
7960         btrfs_free_block_rsv(root, rsv);
7961
7962         if (ret && !err)
7963                 err = ret;
7964
7965         return err;
7966 }
7967
7968 /*
7969  * create a new subvolume directory/inode (helper for the ioctl).
7970  */
7971 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
7972                              struct btrfs_root *new_root,
7973                              struct btrfs_root *parent_root,
7974                              u64 new_dirid)
7975 {
7976         struct inode *inode;
7977         int err;
7978         u64 index = 0;
7979
7980         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
7981                                 new_dirid, new_dirid,
7982                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
7983                                 &index);
7984         if (IS_ERR(inode))
7985                 return PTR_ERR(inode);
7986         inode->i_op = &btrfs_dir_inode_operations;
7987         inode->i_fop = &btrfs_dir_file_operations;
7988
7989         set_nlink(inode, 1);
7990         btrfs_i_size_write(inode, 0);
7991
7992         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
7993         if (err)
7994                 btrfs_err(new_root->fs_info,
7995                           "error inheriting subvolume %llu properties: %d\n",
7996                           new_root->root_key.objectid, err);
7997
7998         err = btrfs_update_inode(trans, new_root, inode);
7999
8000         iput(inode);
8001         return err;
8002 }
8003
8004 struct inode *btrfs_alloc_inode(struct super_block *sb)
8005 {
8006         struct btrfs_inode *ei;
8007         struct inode *inode;
8008
8009         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
8010         if (!ei)
8011                 return NULL;
8012
8013         ei->root = NULL;
8014         ei->generation = 0;
8015         ei->last_trans = 0;
8016         ei->last_sub_trans = 0;
8017         ei->logged_trans = 0;
8018         ei->delalloc_bytes = 0;
8019         ei->disk_i_size = 0;
8020         ei->flags = 0;
8021         ei->csum_bytes = 0;
8022         ei->index_cnt = (u64)-1;
8023         ei->dir_index = 0;
8024         ei->last_unlink_trans = 0;
8025         ei->last_log_commit = 0;
8026
8027         spin_lock_init(&ei->lock);
8028         ei->outstanding_extents = 0;
8029         ei->reserved_extents = 0;
8030
8031         ei->runtime_flags = 0;
8032         ei->force_compress = BTRFS_COMPRESS_NONE;
8033
8034         ei->delayed_node = NULL;
8035
8036         inode = &ei->vfs_inode;
8037         extent_map_tree_init(&ei->extent_tree);
8038         extent_io_tree_init(&ei->io_tree, &inode->i_data);
8039         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
8040         ei->io_tree.track_uptodate = 1;
8041         ei->io_failure_tree.track_uptodate = 1;
8042         atomic_set(&ei->sync_writers, 0);
8043         mutex_init(&ei->log_mutex);
8044         mutex_init(&ei->delalloc_mutex);
8045         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
8046         INIT_LIST_HEAD(&ei->delalloc_inodes);
8047         INIT_LIST_HEAD(&ei->ordered_operations);
8048         RB_CLEAR_NODE(&ei->rb_node);
8049
8050         return inode;
8051 }
8052
8053 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8054 void btrfs_test_destroy_inode(struct inode *inode)
8055 {
8056         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8057         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8058 }
8059 #endif
8060
8061 static void btrfs_i_callback(struct rcu_head *head)
8062 {
8063         struct inode *inode = container_of(head, struct inode, i_rcu);
8064         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8065 }
8066
8067 void btrfs_destroy_inode(struct inode *inode)
8068 {
8069         struct btrfs_ordered_extent *ordered;
8070         struct btrfs_root *root = BTRFS_I(inode)->root;
8071
8072         WARN_ON(!hlist_empty(&inode->i_dentry));
8073         WARN_ON(inode->i_data.nrpages);
8074         WARN_ON(BTRFS_I(inode)->outstanding_extents);
8075         WARN_ON(BTRFS_I(inode)->reserved_extents);
8076         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
8077         WARN_ON(BTRFS_I(inode)->csum_bytes);
8078
8079         /*
8080          * This can happen where we create an inode, but somebody else also
8081          * created the same inode and we need to destroy the one we already
8082          * created.
8083          */
8084         if (!root)
8085                 goto free;
8086
8087         /*
8088          * Make sure we're properly removed from the ordered operation
8089          * lists.
8090          */
8091         smp_mb();
8092         if (!list_empty(&BTRFS_I(inode)->ordered_operations)) {
8093                 spin_lock(&root->fs_info->ordered_root_lock);
8094                 list_del_init(&BTRFS_I(inode)->ordered_operations);
8095                 spin_unlock(&root->fs_info->ordered_root_lock);
8096         }
8097
8098         if (test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
8099                      &BTRFS_I(inode)->runtime_flags)) {
8100                 btrfs_info(root->fs_info, "inode %llu still on the orphan list",
8101                         btrfs_ino(inode));
8102                 atomic_dec(&root->orphan_inodes);
8103         }
8104
8105         while (1) {
8106                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
8107                 if (!ordered)
8108                         break;
8109                 else {
8110                         btrfs_err(root->fs_info, "found ordered extent %llu %llu on inode cleanup",
8111                                 ordered->file_offset, ordered->len);
8112                         btrfs_remove_ordered_extent(inode, ordered);
8113                         btrfs_put_ordered_extent(ordered);
8114                         btrfs_put_ordered_extent(ordered);
8115                 }
8116         }
8117         inode_tree_del(inode);
8118         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8119 free:
8120         call_rcu(&inode->i_rcu, btrfs_i_callback);
8121 }
8122
8123 int btrfs_drop_inode(struct inode *inode)
8124 {
8125         struct btrfs_root *root = BTRFS_I(inode)->root;
8126
8127         if (root == NULL)
8128                 return 1;
8129
8130         /* the snap/subvol tree is on deleting */
8131         if (btrfs_root_refs(&root->root_item) == 0)
8132                 return 1;
8133         else
8134                 return generic_drop_inode(inode);
8135 }
8136
8137 static void init_once(void *foo)
8138 {
8139         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
8140
8141         inode_init_once(&ei->vfs_inode);
8142 }
8143
8144 void btrfs_destroy_cachep(void)
8145 {
8146         /*
8147          * Make sure all delayed rcu free inodes are flushed before we
8148          * destroy cache.
8149          */
8150         rcu_barrier();
8151         if (btrfs_inode_cachep)
8152                 kmem_cache_destroy(btrfs_inode_cachep);
8153         if (btrfs_trans_handle_cachep)
8154                 kmem_cache_destroy(btrfs_trans_handle_cachep);
8155         if (btrfs_transaction_cachep)
8156                 kmem_cache_destroy(btrfs_transaction_cachep);
8157         if (btrfs_path_cachep)
8158                 kmem_cache_destroy(btrfs_path_cachep);
8159         if (btrfs_free_space_cachep)
8160                 kmem_cache_destroy(btrfs_free_space_cachep);
8161         if (btrfs_delalloc_work_cachep)
8162                 kmem_cache_destroy(btrfs_delalloc_work_cachep);
8163 }
8164
8165 int btrfs_init_cachep(void)
8166 {
8167         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
8168                         sizeof(struct btrfs_inode), 0,
8169                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, init_once);
8170         if (!btrfs_inode_cachep)
8171                 goto fail;
8172
8173         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
8174                         sizeof(struct btrfs_trans_handle), 0,
8175                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8176         if (!btrfs_trans_handle_cachep)
8177                 goto fail;
8178
8179         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
8180                         sizeof(struct btrfs_transaction), 0,
8181                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8182         if (!btrfs_transaction_cachep)
8183                 goto fail;
8184
8185         btrfs_path_cachep = kmem_cache_create("btrfs_path",
8186                         sizeof(struct btrfs_path), 0,
8187                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8188         if (!btrfs_path_cachep)
8189                 goto fail;
8190
8191         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
8192                         sizeof(struct btrfs_free_space), 0,
8193                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8194         if (!btrfs_free_space_cachep)
8195                 goto fail;
8196
8197         btrfs_delalloc_work_cachep = kmem_cache_create("btrfs_delalloc_work",
8198                         sizeof(struct btrfs_delalloc_work), 0,
8199                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
8200                         NULL);
8201         if (!btrfs_delalloc_work_cachep)
8202                 goto fail;
8203
8204         return 0;
8205 fail:
8206         btrfs_destroy_cachep();
8207         return -ENOMEM;
8208 }
8209
8210 static int btrfs_getattr(struct vfsmount *mnt,
8211                          struct dentry *dentry, struct kstat *stat)
8212 {
8213         u64 delalloc_bytes;
8214         struct inode *inode = dentry->d_inode;
8215         u32 blocksize = inode->i_sb->s_blocksize;
8216
8217         generic_fillattr(inode, stat);
8218         stat->dev = BTRFS_I(inode)->root->anon_dev;
8219         stat->blksize = PAGE_CACHE_SIZE;
8220
8221         spin_lock(&BTRFS_I(inode)->lock);
8222         delalloc_bytes = BTRFS_I(inode)->delalloc_bytes;
8223         spin_unlock(&BTRFS_I(inode)->lock);
8224         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
8225                         ALIGN(delalloc_bytes, blocksize)) >> 9;
8226         return 0;
8227 }
8228
8229 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
8230                            struct inode *new_dir, struct dentry *new_dentry)
8231 {
8232         struct btrfs_trans_handle *trans;
8233         struct btrfs_root *root = BTRFS_I(old_dir)->root;
8234         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
8235         struct inode *new_inode = new_dentry->d_inode;
8236         struct inode *old_inode = old_dentry->d_inode;
8237         struct timespec ctime = CURRENT_TIME;
8238         u64 index = 0;
8239         u64 root_objectid;
8240         int ret;
8241         u64 old_ino = btrfs_ino(old_inode);
8242
8243         if (btrfs_ino(new_dir) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
8244                 return -EPERM;
8245
8246         /* we only allow rename subvolume link between subvolumes */
8247         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
8248                 return -EXDEV;
8249
8250         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
8251             (new_inode && btrfs_ino(new_inode) == BTRFS_FIRST_FREE_OBJECTID))
8252                 return -ENOTEMPTY;
8253
8254         if (S_ISDIR(old_inode->i_mode) && new_inode &&
8255             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
8256                 return -ENOTEMPTY;
8257
8258
8259         /* check for collisions, even if the  name isn't there */
8260         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
8261                              new_dentry->d_name.name,
8262                              new_dentry->d_name.len);
8263
8264         if (ret) {
8265                 if (ret == -EEXIST) {
8266                         /* we shouldn't get
8267                          * eexist without a new_inode */
8268                         if (WARN_ON(!new_inode)) {
8269                                 return ret;
8270                         }
8271                 } else {
8272                         /* maybe -EOVERFLOW */
8273                         return ret;
8274                 }
8275         }
8276         ret = 0;
8277
8278         /*
8279          * we're using rename to replace one file with another.
8280          * and the replacement file is large.  Start IO on it now so
8281          * we don't add too much work to the end of the transaction
8282          */
8283         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size &&
8284             old_inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
8285                 filemap_flush(old_inode->i_mapping);
8286
8287         /* close the racy window with snapshot create/destroy ioctl */
8288         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8289                 down_read(&root->fs_info->subvol_sem);
8290         /*
8291          * We want to reserve the absolute worst case amount of items.  So if
8292          * both inodes are subvols and we need to unlink them then that would
8293          * require 4 item modifications, but if they are both normal inodes it
8294          * would require 5 item modifications, so we'll assume their normal
8295          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
8296          * should cover the worst case number of items we'll modify.
8297          */
8298         trans = btrfs_start_transaction(root, 11);
8299         if (IS_ERR(trans)) {
8300                 ret = PTR_ERR(trans);
8301                 goto out_notrans;
8302         }
8303
8304         if (dest != root)
8305                 btrfs_record_root_in_trans(trans, dest);
8306
8307         ret = btrfs_set_inode_index(new_dir, &index);
8308         if (ret)
8309                 goto out_fail;
8310
8311         BTRFS_I(old_inode)->dir_index = 0ULL;
8312         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8313                 /* force full log commit if subvolume involved. */
8314                 root->fs_info->last_trans_log_full_commit = trans->transid;
8315         } else {
8316                 ret = btrfs_insert_inode_ref(trans, dest,
8317                                              new_dentry->d_name.name,
8318                                              new_dentry->d_name.len,
8319                                              old_ino,
8320                                              btrfs_ino(new_dir), index);
8321                 if (ret)
8322                         goto out_fail;
8323                 /*
8324                  * this is an ugly little race, but the rename is required
8325                  * to make sure that if we crash, the inode is either at the
8326                  * old name or the new one.  pinning the log transaction lets
8327                  * us make sure we don't allow a log commit to come in after
8328                  * we unlink the name but before we add the new name back in.
8329                  */
8330                 btrfs_pin_log_trans(root);
8331         }
8332         /*
8333          * make sure the inode gets flushed if it is replacing
8334          * something.
8335          */
8336         if (new_inode && new_inode->i_size && S_ISREG(old_inode->i_mode))
8337                 btrfs_add_ordered_operation(trans, root, old_inode);
8338
8339         inode_inc_iversion(old_dir);
8340         inode_inc_iversion(new_dir);
8341         inode_inc_iversion(old_inode);
8342         old_dir->i_ctime = old_dir->i_mtime = ctime;
8343         new_dir->i_ctime = new_dir->i_mtime = ctime;
8344         old_inode->i_ctime = ctime;
8345
8346         if (old_dentry->d_parent != new_dentry->d_parent)
8347                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
8348
8349         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8350                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
8351                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
8352                                         old_dentry->d_name.name,
8353                                         old_dentry->d_name.len);
8354         } else {
8355                 ret = __btrfs_unlink_inode(trans, root, old_dir,
8356                                         old_dentry->d_inode,
8357                                         old_dentry->d_name.name,
8358                                         old_dentry->d_name.len);
8359                 if (!ret)
8360                         ret = btrfs_update_inode(trans, root, old_inode);
8361         }
8362         if (ret) {
8363                 btrfs_abort_transaction(trans, root, ret);
8364                 goto out_fail;
8365         }
8366
8367         if (new_inode) {
8368                 inode_inc_iversion(new_inode);
8369                 new_inode->i_ctime = CURRENT_TIME;
8370                 if (unlikely(btrfs_ino(new_inode) ==
8371                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
8372                         root_objectid = BTRFS_I(new_inode)->location.objectid;
8373                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
8374                                                 root_objectid,
8375                                                 new_dentry->d_name.name,
8376                                                 new_dentry->d_name.len);
8377                         BUG_ON(new_inode->i_nlink == 0);
8378                 } else {
8379                         ret = btrfs_unlink_inode(trans, dest, new_dir,
8380                                                  new_dentry->d_inode,
8381                                                  new_dentry->d_name.name,
8382                                                  new_dentry->d_name.len);
8383                 }
8384                 if (!ret && new_inode->i_nlink == 0)
8385                         ret = btrfs_orphan_add(trans, new_dentry->d_inode);
8386                 if (ret) {
8387                         btrfs_abort_transaction(trans, root, ret);
8388                         goto out_fail;
8389                 }
8390         }
8391
8392         ret = btrfs_add_link(trans, new_dir, old_inode,
8393                              new_dentry->d_name.name,
8394                              new_dentry->d_name.len, 0, index);
8395         if (ret) {
8396                 btrfs_abort_transaction(trans, root, ret);
8397                 goto out_fail;
8398         }
8399
8400         if (old_inode->i_nlink == 1)
8401                 BTRFS_I(old_inode)->dir_index = index;
8402
8403         if (old_ino != BTRFS_FIRST_FREE_OBJECTID) {
8404                 struct dentry *parent = new_dentry->d_parent;
8405                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
8406                 btrfs_end_log_trans(root);
8407         }
8408 out_fail:
8409         btrfs_end_transaction(trans, root);
8410 out_notrans:
8411         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8412                 up_read(&root->fs_info->subvol_sem);
8413
8414         return ret;
8415 }
8416
8417 static void btrfs_run_delalloc_work(struct btrfs_work *work)
8418 {
8419         struct btrfs_delalloc_work *delalloc_work;
8420         struct inode *inode;
8421
8422         delalloc_work = container_of(work, struct btrfs_delalloc_work,
8423                                      work);
8424         inode = delalloc_work->inode;
8425         if (delalloc_work->wait) {
8426                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
8427         } else {
8428                 filemap_flush(inode->i_mapping);
8429                 if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8430                              &BTRFS_I(inode)->runtime_flags))
8431                         filemap_flush(inode->i_mapping);
8432         }
8433
8434         if (delalloc_work->delay_iput)
8435                 btrfs_add_delayed_iput(inode);
8436         else
8437                 iput(inode);
8438         complete(&delalloc_work->completion);
8439 }
8440
8441 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
8442                                                     int wait, int delay_iput)
8443 {
8444         struct btrfs_delalloc_work *work;
8445
8446         work = kmem_cache_zalloc(btrfs_delalloc_work_cachep, GFP_NOFS);
8447         if (!work)
8448                 return NULL;
8449
8450         init_completion(&work->completion);
8451         INIT_LIST_HEAD(&work->list);
8452         work->inode = inode;
8453         work->wait = wait;
8454         work->delay_iput = delay_iput;
8455         btrfs_init_work(&work->work, btrfs_run_delalloc_work, NULL, NULL);
8456
8457         return work;
8458 }
8459
8460 void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
8461 {
8462         wait_for_completion(&work->completion);
8463         kmem_cache_free(btrfs_delalloc_work_cachep, work);
8464 }
8465
8466 /*
8467  * some fairly slow code that needs optimization. This walks the list
8468  * of all the inodes with pending delalloc and forces them to disk.
8469  */
8470 static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput,
8471                                    int nr)
8472 {
8473         struct btrfs_inode *binode;
8474         struct inode *inode;
8475         struct btrfs_delalloc_work *work, *next;
8476         struct list_head works;
8477         struct list_head splice;
8478         int ret = 0;
8479
8480         INIT_LIST_HEAD(&works);
8481         INIT_LIST_HEAD(&splice);
8482
8483         mutex_lock(&root->delalloc_mutex);
8484         spin_lock(&root->delalloc_lock);
8485         list_splice_init(&root->delalloc_inodes, &splice);
8486         while (!list_empty(&splice)) {
8487                 binode = list_entry(splice.next, struct btrfs_inode,
8488                                     delalloc_inodes);
8489
8490                 list_move_tail(&binode->delalloc_inodes,
8491                                &root->delalloc_inodes);
8492                 inode = igrab(&binode->vfs_inode);
8493                 if (!inode) {
8494                         cond_resched_lock(&root->delalloc_lock);
8495                         continue;
8496                 }
8497                 spin_unlock(&root->delalloc_lock);
8498
8499                 work = btrfs_alloc_delalloc_work(inode, 0, delay_iput);
8500                 if (unlikely(!work)) {
8501                         if (delay_iput)
8502                                 btrfs_add_delayed_iput(inode);
8503                         else
8504                                 iput(inode);
8505                         ret = -ENOMEM;
8506                         goto out;
8507                 }
8508                 list_add_tail(&work->list, &works);
8509                 btrfs_queue_work(root->fs_info->flush_workers,
8510                                  &work->work);
8511                 ret++;
8512                 if (nr != -1 && ret >= nr)
8513                         goto out;
8514                 cond_resched();
8515                 spin_lock(&root->delalloc_lock);
8516         }
8517         spin_unlock(&root->delalloc_lock);
8518
8519 out:
8520         list_for_each_entry_safe(work, next, &works, list) {
8521                 list_del_init(&work->list);
8522                 btrfs_wait_and_free_delalloc_work(work);
8523         }
8524
8525         if (!list_empty_careful(&splice)) {
8526                 spin_lock(&root->delalloc_lock);
8527                 list_splice_tail(&splice, &root->delalloc_inodes);
8528                 spin_unlock(&root->delalloc_lock);
8529         }
8530         mutex_unlock(&root->delalloc_mutex);
8531         return ret;
8532 }
8533
8534 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
8535 {
8536         int ret;
8537
8538         if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
8539                 return -EROFS;
8540
8541         ret = __start_delalloc_inodes(root, delay_iput, -1);
8542         if (ret > 0)
8543                 ret = 0;
8544         /*
8545          * the filemap_flush will queue IO into the worker threads, but
8546          * we have to make sure the IO is actually started and that
8547          * ordered extents get created before we return
8548          */
8549         atomic_inc(&root->fs_info->async_submit_draining);
8550         while (atomic_read(&root->fs_info->nr_async_submits) ||
8551               atomic_read(&root->fs_info->async_delalloc_pages)) {
8552                 wait_event(root->fs_info->async_submit_wait,
8553                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
8554                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
8555         }
8556         atomic_dec(&root->fs_info->async_submit_draining);
8557         return ret;
8558 }
8559
8560 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
8561                                int nr)
8562 {
8563         struct btrfs_root *root;
8564         struct list_head splice;
8565         int ret;
8566
8567         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
8568                 return -EROFS;
8569
8570         INIT_LIST_HEAD(&splice);
8571
8572         mutex_lock(&fs_info->delalloc_root_mutex);
8573         spin_lock(&fs_info->delalloc_root_lock);
8574         list_splice_init(&fs_info->delalloc_roots, &splice);
8575         while (!list_empty(&splice) && nr) {
8576                 root = list_first_entry(&splice, struct btrfs_root,
8577                                         delalloc_root);
8578                 root = btrfs_grab_fs_root(root);
8579                 BUG_ON(!root);
8580                 list_move_tail(&root->delalloc_root,
8581                                &fs_info->delalloc_roots);
8582                 spin_unlock(&fs_info->delalloc_root_lock);
8583
8584                 ret = __start_delalloc_inodes(root, delay_iput, nr);
8585                 btrfs_put_fs_root(root);
8586                 if (ret < 0)
8587                         goto out;
8588
8589                 if (nr != -1) {
8590                         nr -= ret;
8591                         WARN_ON(nr < 0);
8592                 }
8593                 spin_lock(&fs_info->delalloc_root_lock);
8594         }
8595         spin_unlock(&fs_info->delalloc_root_lock);
8596
8597         ret = 0;
8598         atomic_inc(&fs_info->async_submit_draining);
8599         while (atomic_read(&fs_info->nr_async_submits) ||
8600               atomic_read(&fs_info->async_delalloc_pages)) {
8601                 wait_event(fs_info->async_submit_wait,
8602                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
8603                     atomic_read(&fs_info->async_delalloc_pages) == 0));
8604         }
8605         atomic_dec(&fs_info->async_submit_draining);
8606 out:
8607         if (!list_empty_careful(&splice)) {
8608                 spin_lock(&fs_info->delalloc_root_lock);
8609                 list_splice_tail(&splice, &fs_info->delalloc_roots);
8610                 spin_unlock(&fs_info->delalloc_root_lock);
8611         }
8612         mutex_unlock(&fs_info->delalloc_root_mutex);
8613         return ret;
8614 }
8615
8616 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
8617                          const char *symname)
8618 {
8619         struct btrfs_trans_handle *trans;
8620         struct btrfs_root *root = BTRFS_I(dir)->root;
8621         struct btrfs_path *path;
8622         struct btrfs_key key;
8623         struct inode *inode = NULL;
8624         int err;
8625         int drop_inode = 0;
8626         u64 objectid;
8627         u64 index = 0;
8628         int name_len;
8629         int datasize;
8630         unsigned long ptr;
8631         struct btrfs_file_extent_item *ei;
8632         struct extent_buffer *leaf;
8633
8634         name_len = strlen(symname);
8635         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
8636                 return -ENAMETOOLONG;
8637
8638         /*
8639          * 2 items for inode item and ref
8640          * 2 items for dir items
8641          * 1 item for xattr if selinux is on
8642          */
8643         trans = btrfs_start_transaction(root, 5);
8644         if (IS_ERR(trans))
8645                 return PTR_ERR(trans);
8646
8647         err = btrfs_find_free_ino(root, &objectid);
8648         if (err)
8649                 goto out_unlock;
8650
8651         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
8652                                 dentry->d_name.len, btrfs_ino(dir), objectid,
8653                                 S_IFLNK|S_IRWXUGO, &index);
8654         if (IS_ERR(inode)) {
8655                 err = PTR_ERR(inode);
8656                 goto out_unlock;
8657         }
8658
8659         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
8660         if (err) {
8661                 drop_inode = 1;
8662                 goto out_unlock;
8663         }
8664
8665         /*
8666         * If the active LSM wants to access the inode during
8667         * d_instantiate it needs these. Smack checks to see
8668         * if the filesystem supports xattrs by looking at the
8669         * ops vector.
8670         */
8671         inode->i_fop = &btrfs_file_operations;
8672         inode->i_op = &btrfs_file_inode_operations;
8673
8674         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
8675         if (err)
8676                 drop_inode = 1;
8677         else {
8678                 inode->i_mapping->a_ops = &btrfs_aops;
8679                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
8680                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
8681         }
8682         if (drop_inode)
8683                 goto out_unlock;
8684
8685         path = btrfs_alloc_path();
8686         if (!path) {
8687                 err = -ENOMEM;
8688                 drop_inode = 1;
8689                 goto out_unlock;
8690         }
8691         key.objectid = btrfs_ino(inode);
8692         key.offset = 0;
8693         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
8694         datasize = btrfs_file_extent_calc_inline_size(name_len);
8695         err = btrfs_insert_empty_item(trans, root, path, &key,
8696                                       datasize);
8697         if (err) {
8698                 drop_inode = 1;
8699                 btrfs_free_path(path);
8700                 goto out_unlock;
8701         }
8702         leaf = path->nodes[0];
8703         ei = btrfs_item_ptr(leaf, path->slots[0],
8704                             struct btrfs_file_extent_item);
8705         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
8706         btrfs_set_file_extent_type(leaf, ei,
8707                                    BTRFS_FILE_EXTENT_INLINE);
8708         btrfs_set_file_extent_encryption(leaf, ei, 0);
8709         btrfs_set_file_extent_compression(leaf, ei, 0);
8710         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
8711         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
8712
8713         ptr = btrfs_file_extent_inline_start(ei);
8714         write_extent_buffer(leaf, symname, ptr, name_len);
8715         btrfs_mark_buffer_dirty(leaf);
8716         btrfs_free_path(path);
8717
8718         inode->i_op = &btrfs_symlink_inode_operations;
8719         inode->i_mapping->a_ops = &btrfs_symlink_aops;
8720         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
8721         inode_set_bytes(inode, name_len);
8722         btrfs_i_size_write(inode, name_len);
8723         err = btrfs_update_inode(trans, root, inode);
8724         if (err)
8725                 drop_inode = 1;
8726
8727 out_unlock:
8728         if (!err)
8729                 d_instantiate(dentry, inode);
8730         btrfs_end_transaction(trans, root);
8731         if (drop_inode) {
8732                 inode_dec_link_count(inode);
8733                 iput(inode);
8734         }
8735         btrfs_btree_balance_dirty(root);
8736         return err;
8737 }
8738
8739 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
8740                                        u64 start, u64 num_bytes, u64 min_size,
8741                                        loff_t actual_len, u64 *alloc_hint,
8742                                        struct btrfs_trans_handle *trans)
8743 {
8744         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
8745         struct extent_map *em;
8746         struct btrfs_root *root = BTRFS_I(inode)->root;
8747         struct btrfs_key ins;
8748         u64 cur_offset = start;
8749         u64 i_size;
8750         u64 cur_bytes;
8751         int ret = 0;
8752         bool own_trans = true;
8753
8754         if (trans)
8755                 own_trans = false;
8756         while (num_bytes > 0) {
8757                 if (own_trans) {
8758                         trans = btrfs_start_transaction(root, 3);
8759                         if (IS_ERR(trans)) {
8760                                 ret = PTR_ERR(trans);
8761                                 break;
8762                         }
8763                 }
8764
8765                 cur_bytes = min(num_bytes, 256ULL * 1024 * 1024);
8766                 cur_bytes = max(cur_bytes, min_size);
8767                 ret = btrfs_reserve_extent(root, cur_bytes, min_size, 0,
8768                                            *alloc_hint, &ins, 1);
8769                 if (ret) {
8770                         if (own_trans)
8771                                 btrfs_end_transaction(trans, root);
8772                         break;
8773                 }
8774
8775                 ret = insert_reserved_file_extent(trans, inode,
8776                                                   cur_offset, ins.objectid,
8777                                                   ins.offset, ins.offset,
8778                                                   ins.offset, 0, 0, 0,
8779                                                   BTRFS_FILE_EXTENT_PREALLOC);
8780                 if (ret) {
8781                         btrfs_free_reserved_extent(root, ins.objectid,
8782                                                    ins.offset);
8783                         btrfs_abort_transaction(trans, root, ret);
8784                         if (own_trans)
8785                                 btrfs_end_transaction(trans, root);
8786                         break;
8787                 }
8788                 btrfs_drop_extent_cache(inode, cur_offset,
8789                                         cur_offset + ins.offset -1, 0);
8790
8791                 em = alloc_extent_map();
8792                 if (!em) {
8793                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
8794                                 &BTRFS_I(inode)->runtime_flags);
8795                         goto next;
8796                 }
8797
8798                 em->start = cur_offset;
8799                 em->orig_start = cur_offset;
8800                 em->len = ins.offset;
8801                 em->block_start = ins.objectid;
8802                 em->block_len = ins.offset;
8803                 em->orig_block_len = ins.offset;
8804                 em->ram_bytes = ins.offset;
8805                 em->bdev = root->fs_info->fs_devices->latest_bdev;
8806                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
8807                 em->generation = trans->transid;
8808
8809                 while (1) {
8810                         write_lock(&em_tree->lock);
8811                         ret = add_extent_mapping(em_tree, em, 1);
8812                         write_unlock(&em_tree->lock);
8813                         if (ret != -EEXIST)
8814                                 break;
8815                         btrfs_drop_extent_cache(inode, cur_offset,
8816                                                 cur_offset + ins.offset - 1,
8817                                                 0);
8818                 }
8819                 free_extent_map(em);
8820 next:
8821                 num_bytes -= ins.offset;
8822                 cur_offset += ins.offset;
8823                 *alloc_hint = ins.objectid + ins.offset;
8824
8825                 inode_inc_iversion(inode);
8826                 inode->i_ctime = CURRENT_TIME;
8827                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
8828                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
8829                     (actual_len > inode->i_size) &&
8830                     (cur_offset > inode->i_size)) {
8831                         if (cur_offset > actual_len)
8832                                 i_size = actual_len;
8833                         else
8834                                 i_size = cur_offset;
8835                         i_size_write(inode, i_size);
8836                         btrfs_ordered_update_i_size(inode, i_size, NULL);
8837                 }
8838
8839                 ret = btrfs_update_inode(trans, root, inode);
8840
8841                 if (ret) {
8842                         btrfs_abort_transaction(trans, root, ret);
8843                         if (own_trans)
8844                                 btrfs_end_transaction(trans, root);
8845                         break;
8846                 }
8847
8848                 if (own_trans)
8849                         btrfs_end_transaction(trans, root);
8850         }
8851         return ret;
8852 }
8853
8854 int btrfs_prealloc_file_range(struct inode *inode, int mode,
8855                               u64 start, u64 num_bytes, u64 min_size,
8856                               loff_t actual_len, u64 *alloc_hint)
8857 {
8858         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
8859                                            min_size, actual_len, alloc_hint,
8860                                            NULL);
8861 }
8862
8863 int btrfs_prealloc_file_range_trans(struct inode *inode,
8864                                     struct btrfs_trans_handle *trans, int mode,
8865                                     u64 start, u64 num_bytes, u64 min_size,
8866                                     loff_t actual_len, u64 *alloc_hint)
8867 {
8868         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
8869                                            min_size, actual_len, alloc_hint, trans);
8870 }
8871
8872 static int btrfs_set_page_dirty(struct page *page)
8873 {
8874         return __set_page_dirty_nobuffers(page);
8875 }
8876
8877 static int btrfs_permission(struct inode *inode, int mask)
8878 {
8879         struct btrfs_root *root = BTRFS_I(inode)->root;
8880         umode_t mode = inode->i_mode;
8881
8882         if (mask & MAY_WRITE &&
8883             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
8884                 if (btrfs_root_readonly(root))
8885                         return -EROFS;
8886                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
8887                         return -EACCES;
8888         }
8889         return generic_permission(inode, mask);
8890 }
8891
8892 static const struct inode_operations btrfs_dir_inode_operations = {
8893         .getattr        = btrfs_getattr,
8894         .lookup         = btrfs_lookup,
8895         .create         = btrfs_create,
8896         .unlink         = btrfs_unlink,
8897         .link           = btrfs_link,
8898         .mkdir          = btrfs_mkdir,
8899         .rmdir          = btrfs_rmdir,
8900         .rename         = btrfs_rename,
8901         .symlink        = btrfs_symlink,
8902         .setattr        = btrfs_setattr,
8903         .mknod          = btrfs_mknod,
8904         .setxattr       = btrfs_setxattr,
8905         .getxattr       = btrfs_getxattr,
8906         .listxattr      = btrfs_listxattr,
8907         .removexattr    = btrfs_removexattr,
8908         .permission     = btrfs_permission,
8909         .get_acl        = btrfs_get_acl,
8910         .set_acl        = btrfs_set_acl,
8911         .update_time    = btrfs_update_time,
8912 };
8913 static const struct inode_operations btrfs_dir_ro_inode_operations = {
8914         .lookup         = btrfs_lookup,
8915         .permission     = btrfs_permission,
8916         .get_acl        = btrfs_get_acl,
8917         .set_acl        = btrfs_set_acl,
8918         .update_time    = btrfs_update_time,
8919 };
8920
8921 static const struct file_operations btrfs_dir_file_operations = {
8922         .llseek         = generic_file_llseek,
8923         .read           = generic_read_dir,
8924         .iterate        = btrfs_real_readdir,
8925         .unlocked_ioctl = btrfs_ioctl,
8926 #ifdef CONFIG_COMPAT
8927         .compat_ioctl   = btrfs_ioctl,
8928 #endif
8929         .release        = btrfs_release_file,
8930         .fsync          = btrfs_sync_file,
8931 };
8932
8933 static struct extent_io_ops btrfs_extent_io_ops = {
8934         .fill_delalloc = run_delalloc_range,
8935         .submit_bio_hook = btrfs_submit_bio_hook,
8936         .merge_bio_hook = btrfs_merge_bio_hook,
8937         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
8938         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
8939         .writepage_start_hook = btrfs_writepage_start_hook,
8940         .set_bit_hook = btrfs_set_bit_hook,
8941         .clear_bit_hook = btrfs_clear_bit_hook,
8942         .merge_extent_hook = btrfs_merge_extent_hook,
8943         .split_extent_hook = btrfs_split_extent_hook,
8944 };
8945
8946 /*
8947  * btrfs doesn't support the bmap operation because swapfiles
8948  * use bmap to make a mapping of extents in the file.  They assume
8949  * these extents won't change over the life of the file and they
8950  * use the bmap result to do IO directly to the drive.
8951  *
8952  * the btrfs bmap call would return logical addresses that aren't
8953  * suitable for IO and they also will change frequently as COW
8954  * operations happen.  So, swapfile + btrfs == corruption.
8955  *
8956  * For now we're avoiding this by dropping bmap.
8957  */
8958 static const struct address_space_operations btrfs_aops = {
8959         .readpage       = btrfs_readpage,
8960         .writepage      = btrfs_writepage,
8961         .writepages     = btrfs_writepages,
8962         .readpages      = btrfs_readpages,
8963         .direct_IO      = btrfs_direct_IO,
8964         .invalidatepage = btrfs_invalidatepage,
8965         .releasepage    = btrfs_releasepage,
8966         .set_page_dirty = btrfs_set_page_dirty,
8967         .error_remove_page = generic_error_remove_page,
8968 };
8969
8970 static const struct address_space_operations btrfs_symlink_aops = {
8971         .readpage       = btrfs_readpage,
8972         .writepage      = btrfs_writepage,
8973         .invalidatepage = btrfs_invalidatepage,
8974         .releasepage    = btrfs_releasepage,
8975 };
8976
8977 static const struct inode_operations btrfs_file_inode_operations = {
8978         .getattr        = btrfs_getattr,
8979         .setattr        = btrfs_setattr,
8980         .setxattr       = btrfs_setxattr,
8981         .getxattr       = btrfs_getxattr,
8982         .listxattr      = btrfs_listxattr,
8983         .removexattr    = btrfs_removexattr,
8984         .permission     = btrfs_permission,
8985         .fiemap         = btrfs_fiemap,
8986         .get_acl        = btrfs_get_acl,
8987         .set_acl        = btrfs_set_acl,
8988         .update_time    = btrfs_update_time,
8989 };
8990 static const struct inode_operations btrfs_special_inode_operations = {
8991         .getattr        = btrfs_getattr,
8992         .setattr        = btrfs_setattr,
8993         .permission     = btrfs_permission,
8994         .setxattr       = btrfs_setxattr,
8995         .getxattr       = btrfs_getxattr,
8996         .listxattr      = btrfs_listxattr,
8997         .removexattr    = btrfs_removexattr,
8998         .get_acl        = btrfs_get_acl,
8999         .set_acl        = btrfs_set_acl,
9000         .update_time    = btrfs_update_time,
9001 };
9002 static const struct inode_operations btrfs_symlink_inode_operations = {
9003         .readlink       = generic_readlink,
9004         .follow_link    = page_follow_link_light,
9005         .put_link       = page_put_link,
9006         .getattr        = btrfs_getattr,
9007         .setattr        = btrfs_setattr,
9008         .permission     = btrfs_permission,
9009         .setxattr       = btrfs_setxattr,
9010         .getxattr       = btrfs_getxattr,
9011         .listxattr      = btrfs_listxattr,
9012         .removexattr    = btrfs_removexattr,
9013         .update_time    = btrfs_update_time,
9014 };
9015
9016 const struct dentry_operations btrfs_dentry_operations = {
9017         .d_delete       = btrfs_dentry_delete,
9018         .d_release      = btrfs_dentry_release,
9019 };