fs/btrfs/disk-io.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/fs.h>
  20 #include <linux/blkdev.h>
  21 #include <linux/scatterlist.h>
  22 #include <linux/swap.h>
  23 #include <linux/radix-tree.h>
  24 #include <linux/writeback.h>
  25 #include <linux/buffer_head.h> // for block_sync_page
  26 #include <linux/workqueue.h>
  27 #include "crc32c.h"
  28 #include "ctree.h"
  29 #include "disk-io.h"
  30 #include "transaction.h"
  31 #include "btrfs_inode.h"
  32 #include "volumes.h"
  33 #include "print-tree.h"
  34 #include "async-thread.h"
  35
  36 #if 0
  37 static int check_tree_block(struct btrfs_root *root, struct extent_buffer *buf)
  38 {
  39         if (extent_buffer_blocknr(buf) != btrfs_header_blocknr(buf)) {
  40                 printk(KERN_CRIT "buf blocknr(buf) is %llu, header is %llu\n",
  41                        (unsigned long long)extent_buffer_blocknr(buf),
  42                        (unsigned long long)btrfs_header_blocknr(buf));
  43                 return 1;
  44         }
  45         return 0;
  46 }
  47 #endif
  48
  49 static struct extent_io_ops btree_extent_io_ops;
  50 static void end_workqueue_fn(struct btrfs_work *work);
  51
  52 struct end_io_wq {
  53         struct bio *bio;
  54         bio_end_io_t *end_io;
  55         void *private;
  56         struct btrfs_fs_info *info;
  57         int error;
  58         int metadata;
  59         struct list_head list;
  60         struct btrfs_work work;
  61 };
  62
  63 struct async_submit_bio {
  64         struct inode *inode;
  65         struct bio *bio;
  66         struct list_head list;
  67         extent_submit_bio_hook_t *submit_bio_hook;
  68         int rw;
  69         int mirror_num;
  70         struct btrfs_work work;
  71 };
  72
  73 struct extent_map *btree_get_extent(struct inode *inode, struct page *page,
  74                                     size_t page_offset, u64 start, u64 len,
  75                                     int create)
  76 {
  77         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
  78         struct extent_map *em;
  79         int ret;
  80
  81         spin_lock(&em_tree->lock);
  82         em = lookup_extent_mapping(em_tree, start, len);
  83         if (em) {
  84                 em->bdev =
  85                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
  86                 spin_unlock(&em_tree->lock);
  87                 goto out;
  88         }
  89         spin_unlock(&em_tree->lock);
  90
  91         em = alloc_extent_map(GFP_NOFS);
  92         if (!em) {
  93                 em = ERR_PTR(-ENOMEM);
  94                 goto out;
  95         }
  96         em->start = 0;
  97         em->len = (u64)-1;
  98         em->block_start = 0;
  99         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 100
 101         spin_lock(&em_tree->lock);
 102         ret = add_extent_mapping(em_tree, em);
 103         if (ret == -EEXIST) {
 104                 u64 failed_start = em->start;
 105                 u64 failed_len = em->len;
 106
 107                 printk("failed to insert %Lu %Lu -> %Lu into tree\n",
 108                        em->start, em->len, em->block_start);
 109                 free_extent_map(em);
 110                 em = lookup_extent_mapping(em_tree, start, len);
 111                 if (em) {
 112                         printk("after failing, found %Lu %Lu %Lu\n",
 113                                em->start, em->len, em->block_start);
 114                         ret = 0;
 115                 } else {
 116                         em = lookup_extent_mapping(em_tree, failed_start,
 117                                                    failed_len);
 118                         if (em) {
 119                                 printk("double failure lookup gives us "
 120                                        "%Lu %Lu -> %Lu\n", em->start,
 121                                        em->len, em->block_start);
 122                                 free_extent_map(em);
 123                         }
 124                         ret = -EIO;
 125                 }
 126         } else if (ret) {
 127                 free_extent_map(em);
 128                 em = NULL;
 129         }
 130         spin_unlock(&em_tree->lock);
 131
 132         if (ret)
 133                 em = ERR_PTR(ret);
 134 out:
 135         return em;
 136 }
 137
 138 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
 139 {
 140         return btrfs_crc32c(seed, data, len);
 141 }
 142
 143 void btrfs_csum_final(u32 crc, char *result)
 144 {
 145         *(__le32 *)result = ~cpu_to_le32(crc);
 146 }
 147
 148 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 149                            int verify)
 150 {
 151         char result[BTRFS_CRC32_SIZE];
 152         unsigned long len;
 153         unsigned long cur_len;
 154         unsigned long offset = BTRFS_CSUM_SIZE;
 155         char *map_token = NULL;
 156         char *kaddr;
 157         unsigned long map_start;
 158         unsigned long map_len;
 159         int err;
 160         u32 crc = ~(u32)0;
 161
 162         len = buf->len - offset;
 163         while(len > 0) {
 164                 err = map_private_extent_buffer(buf, offset, 32,
 165                                         &map_token, &kaddr,
 166                                         &map_start, &map_len, KM_USER0);
 167                 if (err) {
 168                         printk("failed to map extent buffer! %lu\n",
 169                                offset);
 170                         return 1;
 171                 }
 172                 cur_len = min(len, map_len - (offset - map_start));
 173                 crc = btrfs_csum_data(root, kaddr + offset - map_start,
 174                                       crc, cur_len);
 175                 len -= cur_len;
 176                 offset += cur_len;
 177                 unmap_extent_buffer(buf, map_token, KM_USER0);
 178         }
 179         btrfs_csum_final(crc, result);
 180
 181         if (verify) {
 182                 int from_this_trans = 0;
 183
 184                 if (root->fs_info->running_transaction &&
 185                     btrfs_header_generation(buf) ==
 186                     root->fs_info->running_transaction->transid)
 187                         from_this_trans = 1;
 188
 189                 /* FIXME, this is not good */
 190                 if (memcmp_extent_buffer(buf, result, 0, BTRFS_CRC32_SIZE)) {
 191                         u32 val;
 192                         u32 found = 0;
 193                         memcpy(&found, result, BTRFS_CRC32_SIZE);
 194
 195                         read_extent_buffer(buf, &val, 0, BTRFS_CRC32_SIZE);
 196                         printk("btrfs: %s checksum verify failed on %llu "
 197                                "wanted %X found %X from_this_trans %d "
 198                                "level %d\n",
 199                                root->fs_info->sb->s_id,
 200                                buf->start, val, found, from_this_trans,
 201                                btrfs_header_level(buf));
 202                         return 1;
 203                 }
 204         } else {
 205                 write_extent_buffer(buf, result, 0, BTRFS_CRC32_SIZE);
 206         }
 207         return 0;
 208 }
 209
 210 static int verify_parent_transid(struct extent_io_tree *io_tree,
 211                                  struct extent_buffer *eb, u64 parent_transid)
 212 {
 213         int ret;
 214
 215         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
 216                 return 0;
 217
 218         lock_extent(io_tree, eb->start, eb->start + eb->len - 1, GFP_NOFS);
 219         if (extent_buffer_uptodate(io_tree, eb) &&
 220             btrfs_header_generation(eb) == parent_transid) {
 221                 ret = 0;
 222                 goto out;
 223         }
 224         printk("parent transid verify failed on %llu wanted %llu found %llu\n",
 225                (unsigned long long)eb->start,
 226                (unsigned long long)parent_transid,
 227                (unsigned long long)btrfs_header_generation(eb));
 228         ret = 1;
 229 out:
 230         clear_extent_buffer_uptodate(io_tree, eb);
 231         unlock_extent(io_tree, eb->start, eb->start + eb->len - 1,
 232                       GFP_NOFS);
 233         return ret;
 234
 235 }
 236
 237 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
 238                                           struct extent_buffer *eb,
 239                                           u64 start, u64 parent_transid)
 240 {
 241         struct extent_io_tree *io_tree;
 242         int ret;
 243         int num_copies = 0;
 244         int mirror_num = 0;
 245
 246         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
 247         while (1) {
 248                 ret = read_extent_buffer_pages(io_tree, eb, start, 1,
 249                                                btree_get_extent, mirror_num);
 250                 if (!ret &&
 251                     !verify_parent_transid(io_tree, eb, parent_transid))
 252                         return ret;
 253
 254                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
 255                                               eb->start, eb->len);
 256                 if (num_copies == 1)
 257                         return ret;
 258
 259                 mirror_num++;
 260                 if (mirror_num > num_copies)
 261                         return ret;
 262         }
 263         return -EIO;
 264 }
 265
 266 int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 267 {
 268         struct extent_io_tree *tree;
 269         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
 270         u64 found_start;
 271         int found_level;
 272         unsigned long len;
 273         struct extent_buffer *eb;
 274         int ret;
 275
 276         tree = &BTRFS_I(page->mapping->host)->io_tree;
 277
 278         if (page->private == EXTENT_PAGE_PRIVATE)
 279                 goto out;
 280         if (!page->private)
 281                 goto out;
 282         len = page->private >> 2;
 283         if (len == 0) {
 284                 WARN_ON(1);
 285         }
 286         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 287         ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE,
 288                                              btrfs_header_generation(eb));
 289         BUG_ON(ret);
 290         btrfs_clear_buffer_defrag(eb);
 291         found_start = btrfs_header_bytenr(eb);
 292         if (found_start != start) {
 293                 printk("warning: eb start incorrect %Lu buffer %Lu len %lu\n",
 294                        start, found_start, len);
 295                 WARN_ON(1);
 296                 goto err;
 297         }
 298         if (eb->first_page != page) {
 299                 printk("bad first page %lu %lu\n", eb->first_page->index,
 300                        page->index);
 301                 WARN_ON(1);
 302                 goto err;
 303         }
 304         if (!PageUptodate(page)) {
 305                 printk("csum not up to date page %lu\n", page->index);
 306                 WARN_ON(1);
 307                 goto err;
 308         }
 309         found_level = btrfs_header_level(eb);
 310         spin_lock(&root->fs_info->hash_lock);
 311         btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
 312         spin_unlock(&root->fs_info->hash_lock);
 313         csum_tree_block(root, eb, 0);
 314 err:
 315         free_extent_buffer(eb);
 316 out:
 317         return 0;
 318 }
 319
 320 static int btree_writepage_io_hook(struct page *page, u64 start, u64 end)
 321 {
 322         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 323
 324         csum_dirty_buffer(root, page);
 325         return 0;
 326 }
 327
 328 int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
 329                                struct extent_state *state)
 330 {
 331         struct extent_io_tree *tree;
 332         u64 found_start;
 333         int found_level;
 334         unsigned long len;
 335         struct extent_buffer *eb;
 336         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 337         int ret = 0;
 338
 339         tree = &BTRFS_I(page->mapping->host)->io_tree;
 340         if (page->private == EXTENT_PAGE_PRIVATE)
 341                 goto out;
 342         if (!page->private)
 343                 goto out;
 344         len = page->private >> 2;
 345         if (len == 0) {
 346                 WARN_ON(1);
 347         }
 348         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 349
 350         btrfs_clear_buffer_defrag(eb);
 351         found_start = btrfs_header_bytenr(eb);
 352         if (found_start != start) {
 353                 ret = -EIO;
 354                 goto err;
 355         }
 356         if (eb->first_page != page) {
 357                 printk("bad first page %lu %lu\n", eb->first_page->index,
 358                        page->index);
 359                 WARN_ON(1);
 360                 ret = -EIO;
 361                 goto err;
 362         }
 363         if (memcmp_extent_buffer(eb, root->fs_info->fsid,
 364                                  (unsigned long)btrfs_header_fsid(eb),
 365                                  BTRFS_FSID_SIZE)) {
 366                 printk("bad fsid on block %Lu\n", eb->start);
 367                 ret = -EIO;
 368                 goto err;
 369         }
 370         found_level = btrfs_header_level(eb);
 371
 372         ret = csum_tree_block(root, eb, 1);
 373         if (ret)
 374                 ret = -EIO;
 375
 376         end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
 377         end = eb->start + end - 1;
 378         release_extent_buffer_tail_pages(eb);
 379 err:
 380         free_extent_buffer(eb);
 381 out:
 382         return ret;
 383 }
 384
 385 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
 386 static void end_workqueue_bio(struct bio *bio, int err)
 387 #else
 388 static int end_workqueue_bio(struct bio *bio,
 389                                    unsigned int bytes_done, int err)
 390 #endif
 391 {
 392         struct end_io_wq *end_io_wq = bio->bi_private;
 393         struct btrfs_fs_info *fs_info;
 394
 395 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
 396         if (bio->bi_size)
 397                 return 1;
 398 #endif
 399
 400         fs_info = end_io_wq->info;
 401         end_io_wq->error = err;
 402         end_io_wq->work.func = end_workqueue_fn;
 403         end_io_wq->work.flags = 0;
 404         btrfs_queue_worker(&fs_info->endio_workers, &end_io_wq->work);
 405
 406 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
 407         return 0;
 408 #endif
 409 }
 410
 411 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 412                         int metadata)
 413 {
 414         struct end_io_wq *end_io_wq;
 415         end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
 416         if (!end_io_wq)
 417                 return -ENOMEM;
 418
 419         end_io_wq->private = bio->bi_private;
 420         end_io_wq->end_io = bio->bi_end_io;
 421         end_io_wq->info = info;
 422         end_io_wq->error = 0;
 423         end_io_wq->bio = bio;
 424         end_io_wq->metadata = metadata;
 425
 426         bio->bi_private = end_io_wq;
 427         bio->bi_end_io = end_workqueue_bio;
 428         return 0;
 429 }
 430
 431 static void run_one_async_submit(struct btrfs_work *work)
 432 {
 433         struct btrfs_fs_info *fs_info;
 434         struct async_submit_bio *async;
 435
 436         async = container_of(work, struct  async_submit_bio, work);
 437         fs_info = BTRFS_I(async->inode)->root->fs_info;
 438         atomic_dec(&fs_info->nr_async_submits);
 439         async->submit_bio_hook(async->inode, async->rw, async->bio,
 440                                async->mirror_num);
 441         kfree(async);
 442 }
 443
 444 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
 445                         int rw, struct bio *bio, int mirror_num,
 446                         extent_submit_bio_hook_t *submit_bio_hook)
 447 {
 448         struct async_submit_bio *async;
 449
 450         async = kmalloc(sizeof(*async), GFP_NOFS);
 451         if (!async)
 452                 return -ENOMEM;
 453
 454         async->inode = inode;
 455         async->rw = rw;
 456         async->bio = bio;
 457         async->mirror_num = mirror_num;
 458         async->submit_bio_hook = submit_bio_hook;
 459         async->work.func = run_one_async_submit;
 460         async->work.flags = 0;
 461         atomic_inc(&fs_info->nr_async_submits);
 462         btrfs_queue_worker(&fs_info->workers, &async->work);
 463         return 0;
 464 }
 465
 466 static int __btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 467                                  int mirror_num)
 468 {
 469         struct btrfs_root *root = BTRFS_I(inode)->root;
 470         u64 offset;
 471         int ret;
 472
 473         offset = bio->bi_sector << 9;
 474
 475         /*
 476          * when we're called for a write, we're already in the async
 477          * submission context.  Just jump ingo btrfs_map_bio
 478          */
 479         if (rw & (1 << BIO_RW)) {
 480                 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
 481                                      mirror_num, 0);
 482         }
 483
 484         /*
 485          * called for a read, do the setup so that checksum validation
 486          * can happen in the async kernel threads
 487          */
 488         ret = btrfs_bio_wq_end_io(root->fs_info, bio, 1);
 489         BUG_ON(ret);
 490
 491         return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
 492 }
 493
 494 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 495                                  int mirror_num)
 496 {
 497         /*
 498          * kthread helpers are used to submit writes so that checksumming
 499          * can happen in parallel across all CPUs
 500          */
 501         if (!(rw & (1 << BIO_RW))) {
 502                 return __btree_submit_bio_hook(inode, rw, bio, mirror_num);
 503         }
 504         return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
 505                                    inode, rw, bio, mirror_num,
 506                                    __btree_submit_bio_hook);
 507 }
 508
 509 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 510 {
 511         struct extent_io_tree *tree;
 512         tree = &BTRFS_I(page->mapping->host)->io_tree;
 513         return extent_write_full_page(tree, page, btree_get_extent, wbc);
 514 }
 515
 516 static int btree_writepages(struct address_space *mapping,
 517                             struct writeback_control *wbc)
 518 {
 519         struct extent_io_tree *tree;
 520         tree = &BTRFS_I(mapping->host)->io_tree;
 521         if (wbc->sync_mode == WB_SYNC_NONE) {
 522                 u64 num_dirty;
 523                 u64 start = 0;
 524                 unsigned long thresh = 96 * 1024 * 1024;
 525
 526                 if (wbc->for_kupdate)
 527                         return 0;
 528
 529                 if (current_is_pdflush()) {
 530                         thresh = 96 * 1024 * 1024;
 531                 } else {
 532                         thresh = 8 * 1024 * 1024;
 533                 }
 534                 num_dirty = count_range_bits(tree, &start, (u64)-1,
 535                                              thresh, EXTENT_DIRTY);
 536                 if (num_dirty < thresh) {
 537                         return 0;
 538                 }
 539         }
 540         return extent_writepages(tree, mapping, btree_get_extent, wbc);
 541 }
 542
 543 int btree_readpage(struct file *file, struct page *page)
 544 {
 545         struct extent_io_tree *tree;
 546         tree = &BTRFS_I(page->mapping->host)->io_tree;
 547         return extent_read_full_page(tree, page, btree_get_extent);
 548 }
 549
 550 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
 551 {
 552         struct extent_io_tree *tree;
 553         struct extent_map_tree *map;
 554         int ret;
 555
 556         if (page_count(page) > 3) {
 557                 /* once for page->private, once for the caller, once
 558                  * once for the page cache
 559                  */
 560                 return 0;
 561         }
 562         tree = &BTRFS_I(page->mapping->host)->io_tree;
 563         map = &BTRFS_I(page->mapping->host)->extent_tree;
 564         ret = try_release_extent_state(map, tree, page, gfp_flags);
 565         if (ret == 1) {
 566                 invalidate_extent_lru(tree, page_offset(page), PAGE_CACHE_SIZE);
 567                 ClearPagePrivate(page);
 568                 set_page_private(page, 0);
 569                 page_cache_release(page);
 570         }
 571         return ret;
 572 }
 573
 574 static void btree_invalidatepage(struct page *page, unsigned long offset)
 575 {
 576         struct extent_io_tree *tree;
 577         tree = &BTRFS_I(page->mapping->host)->io_tree;
 578         extent_invalidatepage(tree, page, offset);
 579         btree_releasepage(page, GFP_NOFS);
 580         if (PagePrivate(page)) {
 581                 invalidate_extent_lru(tree, page_offset(page), PAGE_CACHE_SIZE);
 582                 ClearPagePrivate(page);
 583                 set_page_private(page, 0);
 584                 page_cache_release(page);
 585         }
 586 }
 587
 588 #if 0
 589 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 590 {
 591         struct buffer_head *bh;
 592         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 593         struct buffer_head *head;
 594         if (!page_has_buffers(page)) {
 595                 create_empty_buffers(page, root->fs_info->sb->s_blocksize,
 596                                         (1 << BH_Dirty)|(1 << BH_Uptodate));
 597         }
 598         head = page_buffers(page);
 599         bh = head;
 600         do {
 601                 if (buffer_dirty(bh))
 602                         csum_tree_block(root, bh, 0);
 603                 bh = bh->b_this_page;
 604         } while (bh != head);
 605         return block_write_full_page(page, btree_get_block, wbc);
 606 }
 607 #endif
 608
 609 static struct address_space_operations btree_aops = {
 610         .readpage       = btree_readpage,
 611         .writepage      = btree_writepage,
 612         .writepages     = btree_writepages,
 613         .releasepage    = btree_releasepage,
 614         .invalidatepage = btree_invalidatepage,
 615         .sync_page      = block_sync_page,
 616 };
 617
 618 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
 619                          u64 parent_transid)
 620 {
 621         struct extent_buffer *buf = NULL;
 622         struct inode *btree_inode = root->fs_info->btree_inode;
 623         int ret = 0;
 624
 625         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 626         if (!buf)
 627                 return 0;
 628         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
 629                                  buf, 0, 0, btree_get_extent, 0);
 630         free_extent_buffer(buf);
 631         return ret;
 632 }
 633
 634 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
 635                                             u64 bytenr, u32 blocksize)
 636 {
 637         struct inode *btree_inode = root->fs_info->btree_inode;
 638         struct extent_buffer *eb;
 639         eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 640                                 bytenr, blocksize, GFP_NOFS);
 641         return eb;
 642 }
 643
 644 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 645                                                  u64 bytenr, u32 blocksize)
 646 {
 647         struct inode *btree_inode = root->fs_info->btree_inode;
 648         struct extent_buffer *eb;
 649
 650         eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 651                                  bytenr, blocksize, NULL, GFP_NOFS);
 652         return eb;
 653 }
 654
 655
 656 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 657                                       u32 blocksize, u64 parent_transid)
 658 {
 659         struct extent_buffer *buf = NULL;
 660         struct inode *btree_inode = root->fs_info->btree_inode;
 661         struct extent_io_tree *io_tree;
 662         int ret;
 663
 664         io_tree = &BTRFS_I(btree_inode)->io_tree;
 665
 666         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 667         if (!buf)
 668                 return NULL;
 669
 670         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
 671
 672         if (ret == 0) {
 673                 buf->flags |= EXTENT_UPTODATE;
 674         }
 675         return buf;
 676
 677 }
 678
 679 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 680                      struct extent_buffer *buf)
 681 {
 682         struct inode *btree_inode = root->fs_info->btree_inode;
 683         if (btrfs_header_generation(buf) ==
 684             root->fs_info->running_transaction->transid)
 685                 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
 686                                           buf);
 687         return 0;
 688 }
 689
 690 int wait_on_tree_block_writeback(struct btrfs_root *root,
 691                                  struct extent_buffer *buf)
 692 {
 693         struct inode *btree_inode = root->fs_info->btree_inode;
 694         wait_on_extent_buffer_writeback(&BTRFS_I(btree_inode)->io_tree,
 695                                         buf);
 696         return 0;
 697 }
 698
 699 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
 700                         u32 stripesize, struct btrfs_root *root,
 701                         struct btrfs_fs_info *fs_info,
 702                         u64 objectid)
 703 {
 704         root->node = NULL;
 705         root->inode = NULL;
 706         root->commit_root = NULL;
 707         root->sectorsize = sectorsize;
 708         root->nodesize = nodesize;
 709         root->leafsize = leafsize;
 710         root->stripesize = stripesize;
 711         root->ref_cows = 0;
 712         root->track_dirty = 0;
 713
 714         root->fs_info = fs_info;
 715         root->objectid = objectid;
 716         root->last_trans = 0;
 717         root->highest_inode = 0;
 718         root->last_inode_alloc = 0;
 719         root->name = NULL;
 720         root->in_sysfs = 0;
 721
 722         INIT_LIST_HEAD(&root->dirty_list);
 723         memset(&root->root_key, 0, sizeof(root->root_key));
 724         memset(&root->root_item, 0, sizeof(root->root_item));
 725         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
 726         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
 727         init_completion(&root->kobj_unregister);
 728         root->defrag_running = 0;
 729         root->defrag_level = 0;
 730         root->root_key.objectid = objectid;
 731         return 0;
 732 }
 733
 734 static int find_and_setup_root(struct btrfs_root *tree_root,
 735                                struct btrfs_fs_info *fs_info,
 736                                u64 objectid,
 737                                struct btrfs_root *root)
 738 {
 739         int ret;
 740         u32 blocksize;
 741
 742         __setup_root(tree_root->nodesize, tree_root->leafsize,
 743                      tree_root->sectorsize, tree_root->stripesize,
 744                      root, fs_info, objectid);
 745         ret = btrfs_find_last_root(tree_root, objectid,
 746                                    &root->root_item, &root->root_key);
 747         BUG_ON(ret);
 748
 749         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
 750         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
 751                                      blocksize, 0);
 752         BUG_ON(!root->node);
 753         return 0;
 754 }
 755
 756 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_fs_info *fs_info,
 757                                                struct btrfs_key *location)
 758 {
 759         struct btrfs_root *root;
 760         struct btrfs_root *tree_root = fs_info->tree_root;
 761         struct btrfs_path *path;
 762         struct extent_buffer *l;
 763         u64 highest_inode;
 764         u32 blocksize;
 765         int ret = 0;
 766
 767         root = kzalloc(sizeof(*root), GFP_NOFS);
 768         if (!root)
 769                 return ERR_PTR(-ENOMEM);
 770         if (location->offset == (u64)-1) {
 771                 ret = find_and_setup_root(tree_root, fs_info,
 772                                           location->objectid, root);
 773                 if (ret) {
 774                         kfree(root);
 775                         return ERR_PTR(ret);
 776                 }
 777                 goto insert;
 778         }
 779
 780         __setup_root(tree_root->nodesize, tree_root->leafsize,
 781                      tree_root->sectorsize, tree_root->stripesize,
 782                      root, fs_info, location->objectid);
 783
 784         path = btrfs_alloc_path();
 785         BUG_ON(!path);
 786         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
 787         if (ret != 0) {
 788                 if (ret > 0)
 789                         ret = -ENOENT;
 790                 goto out;
 791         }
 792         l = path->nodes[0];
 793         read_extent_buffer(l, &root->root_item,
 794                btrfs_item_ptr_offset(l, path->slots[0]),
 795                sizeof(root->root_item));
 796         memcpy(&root->root_key, location, sizeof(*location));
 797         ret = 0;
 798 out:
 799         btrfs_release_path(root, path);
 800         btrfs_free_path(path);
 801         if (ret) {
 802                 kfree(root);
 803                 return ERR_PTR(ret);
 804         }
 805         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
 806         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
 807                                      blocksize, 0);
 808         BUG_ON(!root->node);
 809 insert:
 810         root->ref_cows = 1;
 811         ret = btrfs_find_highest_inode(root, &highest_inode);
 812         if (ret == 0) {
 813                 root->highest_inode = highest_inode;
 814                 root->last_inode_alloc = highest_inode;
 815         }
 816         return root;
 817 }
 818
 819 struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
 820                                         u64 root_objectid)
 821 {
 822         struct btrfs_root *root;
 823
 824         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID)
 825                 return fs_info->tree_root;
 826         if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID)
 827                 return fs_info->extent_root;
 828
 829         root = radix_tree_lookup(&fs_info->fs_roots_radix,
 830                                  (unsigned long)root_objectid);
 831         return root;
 832 }
 833
 834 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
 835                                               struct btrfs_key *location)
 836 {
 837         struct btrfs_root *root;
 838         int ret;
 839
 840         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
 841                 return fs_info->tree_root;
 842         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
 843                 return fs_info->extent_root;
 844         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
 845                 return fs_info->chunk_root;
 846         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
 847                 return fs_info->dev_root;
 848
 849         root = radix_tree_lookup(&fs_info->fs_roots_radix,
 850                                  (unsigned long)location->objectid);
 851         if (root)
 852                 return root;
 853
 854         root = btrfs_read_fs_root_no_radix(fs_info, location);
 855         if (IS_ERR(root))
 856                 return root;
 857         ret = radix_tree_insert(&fs_info->fs_roots_radix,
 858                                 (unsigned long)root->root_key.objectid,
 859                                 root);
 860         if (ret) {
 861                 free_extent_buffer(root->node);
 862                 kfree(root);
 863                 return ERR_PTR(ret);
 864         }
 865         ret = btrfs_find_dead_roots(fs_info->tree_root,
 866                                     root->root_key.objectid, root);
 867         BUG_ON(ret);
 868
 869         return root;
 870 }
 871
 872 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 873                                       struct btrfs_key *location,
 874                                       const char *name, int namelen)
 875 {
 876         struct btrfs_root *root;
 877         int ret;
 878
 879         root = btrfs_read_fs_root_no_name(fs_info, location);
 880         if (!root)
 881                 return NULL;
 882
 883         if (root->in_sysfs)
 884                 return root;
 885
 886         ret = btrfs_set_root_name(root, name, namelen);
 887         if (ret) {
 888                 free_extent_buffer(root->node);
 889                 kfree(root);
 890                 return ERR_PTR(ret);
 891         }
 892
 893         ret = btrfs_sysfs_add_root(root);
 894         if (ret) {
 895                 free_extent_buffer(root->node);
 896                 kfree(root->name);
 897                 kfree(root);
 898                 return ERR_PTR(ret);
 899         }
 900         root->in_sysfs = 1;
 901         return root;
 902 }
 903 #if 0
 904 static int add_hasher(struct btrfs_fs_info *info, char *type) {
 905         struct btrfs_hasher *hasher;
 906
 907         hasher = kmalloc(sizeof(*hasher), GFP_NOFS);
 908         if (!hasher)
 909                 return -ENOMEM;
 910         hasher->hash_tfm = crypto_alloc_hash(type, 0, CRYPTO_ALG_ASYNC);
 911         if (!hasher->hash_tfm) {
 912                 kfree(hasher);
 913                 return -EINVAL;
 914         }
 915         spin_lock(&info->hash_lock);
 916         list_add(&hasher->list, &info->hashers);
 917         spin_unlock(&info->hash_lock);
 918         return 0;
 919 }
 920 #endif
 921
 922 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
 923 {
 924         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
 925         int ret = 0;
 926         int limit = 256 * info->fs_devices->open_devices;
 927         struct list_head *cur;
 928         struct btrfs_device *device;
 929         struct backing_dev_info *bdi;
 930
 931         if ((bdi_bits & (1 << BDI_write_congested)) &&
 932             atomic_read(&info->nr_async_submits) > limit) {
 933                 return 1;
 934         }
 935
 936         list_for_each(cur, &info->fs_devices->devices) {
 937                 device = list_entry(cur, struct btrfs_device, dev_list);
 938                 if (!device->bdev)
 939                         continue;
 940                 bdi = blk_get_backing_dev_info(device->bdev);
 941                 if (bdi && bdi_congested(bdi, bdi_bits)) {
 942                         ret = 1;
 943                         break;
 944                 }
 945         }
 946         return ret;
 947 }
 948
 949 /*
 950  * this unplugs every device on the box, and it is only used when page
 951  * is null
 952  */
 953 static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
 954 {
 955         struct list_head *cur;
 956         struct btrfs_device *device;
 957         struct btrfs_fs_info *info;
 958
 959         info = (struct btrfs_fs_info *)bdi->unplug_io_data;
 960         list_for_each(cur, &info->fs_devices->devices) {
 961                 device = list_entry(cur, struct btrfs_device, dev_list);
 962                 bdi = blk_get_backing_dev_info(device->bdev);
 963                 if (bdi->unplug_io_fn) {
 964                         bdi->unplug_io_fn(bdi, page);
 965                 }
 966         }
 967 }
 968
 969 void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
 970 {
 971         struct inode *inode;
 972         struct extent_map_tree *em_tree;
 973         struct extent_map *em;
 974         struct address_space *mapping;
 975         u64 offset;
 976
 977         /* the generic O_DIRECT read code does this */
 978         if (!page) {
 979                 __unplug_io_fn(bdi, page);
 980                 return;
 981         }
 982
 983         /*
 984          * page->mapping may change at any time.  Get a consistent copy
 985          * and use that for everything below
 986          */
 987         smp_mb();
 988         mapping = page->mapping;
 989         if (!mapping)
 990                 return;
 991
 992         inode = mapping->host;
 993         offset = page_offset(page);
 994
 995         em_tree = &BTRFS_I(inode)->extent_tree;
 996         spin_lock(&em_tree->lock);
 997         em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
 998         spin_unlock(&em_tree->lock);
 999         if (!em)
1000                 return;
1001
1002         offset = offset - em->start;
1003         btrfs_unplug_page(&BTRFS_I(inode)->root->fs_info->mapping_tree,
1004                           em->block_start + offset, page);
1005         free_extent_map(em);
1006 }
1007
1008 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1009 {
1010 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1011         bdi_init(bdi);
1012 #endif
1013         bdi->ra_pages   = default_backing_dev_info.ra_pages;
1014         bdi->state              = 0;
1015         bdi->capabilities       = default_backing_dev_info.capabilities;
1016         bdi->unplug_io_fn       = btrfs_unplug_io_fn;
1017         bdi->unplug_io_data     = info;
1018         bdi->congested_fn       = btrfs_congested_fn;
1019         bdi->congested_data     = info;
1020         return 0;
1021 }
1022
1023 static int bio_ready_for_csum(struct bio *bio)
1024 {
1025         u64 length = 0;
1026         u64 buf_len = 0;
1027         u64 start = 0;
1028         struct page *page;
1029         struct extent_io_tree *io_tree = NULL;
1030         struct btrfs_fs_info *info = NULL;
1031         struct bio_vec *bvec;
1032         int i;
1033         int ret;
1034
1035         bio_for_each_segment(bvec, bio, i) {
1036                 page = bvec->bv_page;
1037                 if (page->private == EXTENT_PAGE_PRIVATE) {
1038                         length += bvec->bv_len;
1039                         continue;
1040                 }
1041                 if (!page->private) {
1042                         length += bvec->bv_len;
1043                         continue;
1044                 }
1045                 length = bvec->bv_len;
1046                 buf_len = page->private >> 2;
1047                 start = page_offset(page) + bvec->bv_offset;
1048                 io_tree = &BTRFS_I(page->mapping->host)->io_tree;
1049                 info = BTRFS_I(page->mapping->host)->root->fs_info;
1050         }
1051         /* are we fully contained in this bio? */
1052         if (buf_len <= length)
1053                 return 1;
1054
1055         ret = extent_range_uptodate(io_tree, start + length,
1056                                     start + buf_len - 1);
1057         if (ret == 1)
1058                 return ret;
1059         return ret;
1060 }
1061
1062 /*
1063  * called by the kthread helper functions to finally call the bio end_io
1064  * functions.  This is where read checksum verification actually happens
1065  */
1066 static void end_workqueue_fn(struct btrfs_work *work)
1067 {
1068         struct bio *bio;
1069         struct end_io_wq *end_io_wq;
1070         struct btrfs_fs_info *fs_info;
1071         int error;
1072
1073         end_io_wq = container_of(work, struct end_io_wq, work);
1074         bio = end_io_wq->bio;
1075         fs_info = end_io_wq->info;
1076
1077         /* metadata bios are special because the whole tree block must
1078          * be checksummed at once.  This makes sure the entire block is in
1079          * ram and up to date before trying to verify things.  For
1080          * blocksize <= pagesize, it is basically a noop
1081          */
1082         if (end_io_wq->metadata && !bio_ready_for_csum(bio)) {
1083                 btrfs_queue_worker(&fs_info->endio_workers,
1084                                    &end_io_wq->work);
1085                 return;
1086         }
1087         error = end_io_wq->error;
1088         bio->bi_private = end_io_wq->private;
1089         bio->bi_end_io = end_io_wq->end_io;
1090         kfree(end_io_wq);
1091 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1092         bio_endio(bio, bio->bi_size, error);
1093 #else
1094         bio_endio(bio, error);
1095 #endif
1096 }
1097
1098 struct btrfs_root *open_ctree(struct super_block *sb,
1099                               struct btrfs_fs_devices *fs_devices,
1100                               char *options)
1101 {
1102         u32 sectorsize;
1103         u32 nodesize;
1104         u32 leafsize;
1105         u32 blocksize;
1106         u32 stripesize;
1107         struct buffer_head *bh;
1108         struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
1109                                                  GFP_NOFS);
1110         struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
1111                                                GFP_NOFS);
1112         struct btrfs_fs_info *fs_info = kzalloc(sizeof(*fs_info),
1113                                                 GFP_NOFS);
1114         struct btrfs_root *chunk_root = kmalloc(sizeof(struct btrfs_root),
1115                                                 GFP_NOFS);
1116         struct btrfs_root *dev_root = kmalloc(sizeof(struct btrfs_root),
1117                                               GFP_NOFS);
1118         int ret;
1119         int err = -EINVAL;
1120
1121         struct btrfs_super_block *disk_super;
1122
1123         if (!extent_root || !tree_root || !fs_info) {
1124                 err = -ENOMEM;
1125                 goto fail;
1126         }
1127         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
1128         INIT_LIST_HEAD(&fs_info->trans_list);
1129         INIT_LIST_HEAD(&fs_info->dead_roots);
1130         INIT_LIST_HEAD(&fs_info->hashers);
1131         spin_lock_init(&fs_info->hash_lock);
1132         spin_lock_init(&fs_info->delalloc_lock);
1133         spin_lock_init(&fs_info->new_trans_lock);
1134
1135         init_completion(&fs_info->kobj_unregister);
1136         fs_info->tree_root = tree_root;
1137         fs_info->extent_root = extent_root;
1138         fs_info->chunk_root = chunk_root;
1139         fs_info->dev_root = dev_root;
1140         fs_info->fs_devices = fs_devices;
1141         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
1142         INIT_LIST_HEAD(&fs_info->space_info);
1143         btrfs_mapping_init(&fs_info->mapping_tree);
1144         atomic_set(&fs_info->nr_async_submits, 0);
1145         fs_info->sb = sb;
1146         fs_info->max_extent = (u64)-1;
1147         fs_info->max_inline = 8192 * 1024;
1148         setup_bdi(fs_info, &fs_info->bdi);
1149         fs_info->btree_inode = new_inode(sb);
1150         fs_info->btree_inode->i_ino = 1;
1151         fs_info->btree_inode->i_nlink = 1;
1152         fs_info->thread_pool_size = min(num_online_cpus() + 2, 8);
1153
1154         sb->s_blocksize = 4096;
1155         sb->s_blocksize_bits = blksize_bits(4096);
1156
1157         /*
1158          * we set the i_size on the btree inode to the max possible int.
1159          * the real end of the address space is determined by all of
1160          * the devices in the system
1161          */
1162         fs_info->btree_inode->i_size = OFFSET_MAX;
1163         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
1164         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
1165
1166         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
1167                              fs_info->btree_inode->i_mapping,
1168                              GFP_NOFS);
1169         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree,
1170                              GFP_NOFS);
1171
1172         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
1173
1174         extent_io_tree_init(&fs_info->free_space_cache,
1175                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1176         extent_io_tree_init(&fs_info->block_group_cache,
1177                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1178         extent_io_tree_init(&fs_info->pinned_extents,
1179                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1180         extent_io_tree_init(&fs_info->pending_del,
1181                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1182         extent_io_tree_init(&fs_info->extent_ins,
1183                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1184         fs_info->do_barriers = 1;
1185
1186 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
1187         INIT_WORK(&fs_info->trans_work, btrfs_transaction_cleaner, fs_info);
1188 #else
1189         INIT_DELAYED_WORK(&fs_info->trans_work, btrfs_transaction_cleaner);
1190 #endif
1191         BTRFS_I(fs_info->btree_inode)->root = tree_root;
1192         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
1193                sizeof(struct btrfs_key));
1194         insert_inode_hash(fs_info->btree_inode);
1195         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
1196
1197         mutex_init(&fs_info->trans_mutex);
1198         mutex_init(&fs_info->fs_mutex);
1199
1200 #if 0
1201         ret = add_hasher(fs_info, "crc32c");
1202         if (ret) {
1203                 printk("btrfs: failed hash setup, modprobe cryptomgr?\n");
1204                 err = -ENOMEM;
1205                 goto fail_iput;
1206         }
1207 #endif
1208         __setup_root(4096, 4096, 4096, 4096, tree_root,
1209                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
1210
1211
1212         bh = __bread(fs_devices->latest_bdev,
1213                      BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
1214         if (!bh)
1215                 goto fail_iput;
1216
1217         memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));
1218         brelse(bh);
1219
1220         memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
1221
1222         disk_super = &fs_info->super_copy;
1223         if (!btrfs_super_root(disk_super))
1224                 goto fail_sb_buffer;
1225
1226         err = btrfs_parse_options(tree_root, options);
1227         if (err)
1228                 goto fail_sb_buffer;
1229
1230         /*
1231          * we need to start all the end_io workers up front because the
1232          * queue work function gets called at interrupt time, and so it
1233          * cannot dynamically grow.
1234          */
1235         btrfs_init_workers(&fs_info->workers, fs_info->thread_pool_size);
1236         btrfs_init_workers(&fs_info->endio_workers, fs_info->thread_pool_size);
1237         btrfs_start_workers(&fs_info->workers, 1);
1238         btrfs_start_workers(&fs_info->endio_workers, fs_info->thread_pool_size);
1239
1240
1241         err = -EINVAL;
1242         if (btrfs_super_num_devices(disk_super) > fs_devices->open_devices) {
1243                 printk("Btrfs: wanted %llu devices, but found %llu\n",
1244                        (unsigned long long)btrfs_super_num_devices(disk_super),
1245                        (unsigned long long)fs_devices->open_devices);
1246                 if (btrfs_test_opt(tree_root, DEGRADED))
1247                         printk("continuing in degraded mode\n");
1248                 else {
1249                         goto fail_sb_buffer;
1250                 }
1251         }
1252
1253         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
1254
1255         nodesize = btrfs_super_nodesize(disk_super);
1256         leafsize = btrfs_super_leafsize(disk_super);
1257         sectorsize = btrfs_super_sectorsize(disk_super);
1258         stripesize = btrfs_super_stripesize(disk_super);
1259         tree_root->nodesize = nodesize;
1260         tree_root->leafsize = leafsize;
1261         tree_root->sectorsize = sectorsize;
1262         tree_root->stripesize = stripesize;
1263
1264         sb->s_blocksize = sectorsize;
1265         sb->s_blocksize_bits = blksize_bits(sectorsize);
1266
1267         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
1268                     sizeof(disk_super->magic))) {
1269                 printk("btrfs: valid FS not found on %s\n", sb->s_id);
1270                 goto fail_sb_buffer;
1271         }
1272
1273         mutex_lock(&fs_info->fs_mutex);
1274
1275         ret = btrfs_read_sys_array(tree_root);
1276         if (ret) {
1277                 printk("btrfs: failed to read the system array on %s\n",
1278                        sb->s_id);
1279                 goto fail_sys_array;
1280         }
1281
1282         blocksize = btrfs_level_size(tree_root,
1283                                      btrfs_super_chunk_root_level(disk_super));
1284
1285         __setup_root(nodesize, leafsize, sectorsize, stripesize,
1286                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
1287
1288         chunk_root->node = read_tree_block(chunk_root,
1289                                            btrfs_super_chunk_root(disk_super),
1290                                            blocksize, 0);
1291         BUG_ON(!chunk_root->node);
1292
1293         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
1294                  (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
1295                  BTRFS_UUID_SIZE);
1296
1297         ret = btrfs_read_chunk_tree(chunk_root);
1298         BUG_ON(ret);
1299
1300         btrfs_close_extra_devices(fs_devices);
1301
1302         blocksize = btrfs_level_size(tree_root,
1303                                      btrfs_super_root_level(disk_super));
1304
1305
1306         tree_root->node = read_tree_block(tree_root,
1307                                           btrfs_super_root(disk_super),
1308                                           blocksize, 0);
1309         if (!tree_root->node)
1310                 goto fail_sb_buffer;
1311
1312
1313         ret = find_and_setup_root(tree_root, fs_info,
1314                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
1315         if (ret)
1316                 goto fail_tree_root;
1317         extent_root->track_dirty = 1;
1318
1319         ret = find_and_setup_root(tree_root, fs_info,
1320                                   BTRFS_DEV_TREE_OBJECTID, dev_root);
1321         dev_root->track_dirty = 1;
1322
1323         if (ret)
1324                 goto fail_extent_root;
1325
1326         btrfs_read_block_groups(extent_root);
1327
1328         fs_info->generation = btrfs_super_generation(disk_super) + 1;
1329         fs_info->data_alloc_profile = (u64)-1;
1330         fs_info->metadata_alloc_profile = (u64)-1;
1331         fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
1332
1333         mutex_unlock(&fs_info->fs_mutex);
1334         return tree_root;
1335
1336 fail_extent_root:
1337         free_extent_buffer(extent_root->node);
1338 fail_tree_root:
1339         free_extent_buffer(tree_root->node);
1340 fail_sys_array:
1341         mutex_unlock(&fs_info->fs_mutex);
1342 fail_sb_buffer:
1343         extent_io_tree_empty_lru(&BTRFS_I(fs_info->btree_inode)->io_tree);
1344         btrfs_stop_workers(&fs_info->workers);
1345         btrfs_stop_workers(&fs_info->endio_workers);
1346 fail_iput:
1347         iput(fs_info->btree_inode);
1348 fail:
1349         btrfs_close_devices(fs_info->fs_devices);
1350         btrfs_mapping_tree_free(&fs_info->mapping_tree);
1351
1352         kfree(extent_root);
1353         kfree(tree_root);
1354 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1355         bdi_destroy(&fs_info->bdi);
1356 #endif
1357         kfree(fs_info);
1358         return ERR_PTR(err);
1359 }
1360
1361 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
1362 {
1363         char b[BDEVNAME_SIZE];
1364
1365         if (uptodate) {
1366                 set_buffer_uptodate(bh);
1367         } else {
1368                 if (!buffer_eopnotsupp(bh) && printk_ratelimit()) {
1369                         printk(KERN_WARNING "lost page write due to "
1370                                         "I/O error on %s\n",
1371                                        bdevname(bh->b_bdev, b));
1372                 }
1373                 /* note, we dont' set_buffer_write_io_error because we have
1374                  * our own ways of dealing with the IO errors
1375                  */
1376                 clear_buffer_uptodate(bh);
1377         }
1378         unlock_buffer(bh);
1379         put_bh(bh);
1380 }
1381
1382 int write_all_supers(struct btrfs_root *root)
1383 {
1384         struct list_head *cur;
1385         struct list_head *head = &root->fs_info->fs_devices->devices;
1386         struct btrfs_device *dev;
1387         struct btrfs_super_block *sb;
1388         struct btrfs_dev_item *dev_item;
1389         struct buffer_head *bh;
1390         int ret;
1391         int do_barriers;
1392         int max_errors;
1393         int total_errors = 0;
1394         u32 crc;
1395         u64 flags;
1396
1397         max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
1398         do_barriers = !btrfs_test_opt(root, NOBARRIER);
1399
1400         sb = &root->fs_info->super_for_commit;
1401         dev_item = &sb->dev_item;
1402         list_for_each(cur, head) {
1403                 dev = list_entry(cur, struct btrfs_device, dev_list);
1404                 if (!dev->bdev) {
1405                         total_errors++;
1406                         continue;
1407                 }
1408                 if (!dev->in_fs_metadata)
1409                         continue;
1410
1411                 btrfs_set_stack_device_type(dev_item, dev->type);
1412                 btrfs_set_stack_device_id(dev_item, dev->devid);
1413                 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
1414                 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
1415                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
1416                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
1417                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
1418                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
1419                 flags = btrfs_super_flags(sb);
1420                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
1421
1422
1423                 crc = ~(u32)0;
1424                 crc = btrfs_csum_data(root, (char *)sb + BTRFS_CSUM_SIZE, crc,
1425                                       BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
1426                 btrfs_csum_final(crc, sb->csum);
1427
1428                 bh = __getblk(dev->bdev, BTRFS_SUPER_INFO_OFFSET / 4096,
1429                               BTRFS_SUPER_INFO_SIZE);
1430
1431                 memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
1432                 dev->pending_io = bh;
1433
1434                 get_bh(bh);
1435                 set_buffer_uptodate(bh);
1436                 lock_buffer(bh);
1437                 bh->b_end_io = btrfs_end_buffer_write_sync;
1438
1439                 if (do_barriers && dev->barriers) {
1440                         ret = submit_bh(WRITE_BARRIER, bh);
1441                         if (ret == -EOPNOTSUPP) {
1442                                 printk("btrfs: disabling barriers on dev %s\n",
1443                                        dev->name);
1444                                 set_buffer_uptodate(bh);
1445                                 dev->barriers = 0;
1446                                 get_bh(bh);
1447                                 lock_buffer(bh);
1448                                 ret = submit_bh(WRITE, bh);
1449                         }
1450                 } else {
1451                         ret = submit_bh(WRITE, bh);
1452                 }
1453                 if (ret)
1454                         total_errors++;
1455         }
1456         if (total_errors > max_errors) {
1457                 printk("btrfs: %d errors while writing supers\n", total_errors);
1458                 BUG();
1459         }
1460         total_errors = 0;
1461
1462         list_for_each(cur, head) {
1463                 dev = list_entry(cur, struct btrfs_device, dev_list);
1464                 if (!dev->bdev)
1465                         continue;
1466                 if (!dev->in_fs_metadata)
1467                         continue;
1468
1469                 BUG_ON(!dev->pending_io);
1470                 bh = dev->pending_io;
1471                 wait_on_buffer(bh);
1472                 if (!buffer_uptodate(dev->pending_io)) {
1473                         if (do_barriers && dev->barriers) {
1474                                 printk("btrfs: disabling barriers on dev %s\n",
1475                                        dev->name);
1476                                 set_buffer_uptodate(bh);
1477                                 get_bh(bh);
1478                                 lock_buffer(bh);
1479                                 dev->barriers = 0;
1480                                 ret = submit_bh(WRITE, bh);
1481                                 BUG_ON(ret);
1482                                 wait_on_buffer(bh);
1483                                 if (!buffer_uptodate(bh))
1484                                         total_errors++;
1485                         } else {
1486                                 total_errors++;
1487                         }
1488
1489                 }
1490                 dev->pending_io = NULL;
1491                 brelse(bh);
1492         }
1493         if (total_errors > max_errors) {
1494                 printk("btrfs: %d errors while writing supers\n", total_errors);
1495                 BUG();
1496         }
1497         return 0;
1498 }
1499
1500 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
1501                       *root)
1502 {
1503         int ret;
1504
1505         ret = write_all_supers(root);
1506         return ret;
1507 }
1508
1509 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
1510 {
1511         radix_tree_delete(&fs_info->fs_roots_radix,
1512                           (unsigned long)root->root_key.objectid);
1513         if (root->in_sysfs)
1514                 btrfs_sysfs_del_root(root);
1515         if (root->inode)
1516                 iput(root->inode);
1517         if (root->node)
1518                 free_extent_buffer(root->node);
1519         if (root->commit_root)
1520                 free_extent_buffer(root->commit_root);
1521         if (root->name)
1522                 kfree(root->name);
1523         kfree(root);
1524         return 0;
1525 }
1526
1527 static int del_fs_roots(struct btrfs_fs_info *fs_info)
1528 {
1529         int ret;
1530         struct btrfs_root *gang[8];
1531         int i;
1532
1533         while(1) {
1534                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
1535                                              (void **)gang, 0,
1536                                              ARRAY_SIZE(gang));
1537                 if (!ret)
1538                         break;
1539                 for (i = 0; i < ret; i++)
1540                         btrfs_free_fs_root(fs_info, gang[i]);
1541         }
1542         return 0;
1543 }
1544
1545 int close_ctree(struct btrfs_root *root)
1546 {
1547         int ret;
1548         struct btrfs_trans_handle *trans;
1549         struct btrfs_fs_info *fs_info = root->fs_info;
1550
1551         fs_info->closing = 1;
1552         btrfs_transaction_flush_work(root);
1553         mutex_lock(&fs_info->fs_mutex);
1554         btrfs_defrag_dirty_roots(root->fs_info);
1555         trans = btrfs_start_transaction(root, 1);
1556         ret = btrfs_commit_transaction(trans, root);
1557         /* run commit again to  drop the original snapshot */
1558         trans = btrfs_start_transaction(root, 1);
1559         btrfs_commit_transaction(trans, root);
1560         ret = btrfs_write_and_wait_transaction(NULL, root);
1561         BUG_ON(ret);
1562
1563         write_ctree_super(NULL, root);
1564         mutex_unlock(&fs_info->fs_mutex);
1565
1566         btrfs_transaction_flush_work(root);
1567
1568         if (fs_info->delalloc_bytes) {
1569                 printk("btrfs: at unmount delalloc count %Lu\n",
1570                        fs_info->delalloc_bytes);
1571         }
1572         if (fs_info->extent_root->node)
1573                 free_extent_buffer(fs_info->extent_root->node);
1574
1575         if (fs_info->tree_root->node)
1576                 free_extent_buffer(fs_info->tree_root->node);
1577
1578         if (root->fs_info->chunk_root->node);
1579                 free_extent_buffer(root->fs_info->chunk_root->node);
1580
1581         if (root->fs_info->dev_root->node);
1582                 free_extent_buffer(root->fs_info->dev_root->node);
1583
1584         btrfs_free_block_groups(root->fs_info);
1585         del_fs_roots(fs_info);
1586
1587         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
1588
1589         extent_io_tree_empty_lru(&fs_info->free_space_cache);
1590         extent_io_tree_empty_lru(&fs_info->block_group_cache);
1591         extent_io_tree_empty_lru(&fs_info->pinned_extents);
1592         extent_io_tree_empty_lru(&fs_info->pending_del);
1593         extent_io_tree_empty_lru(&fs_info->extent_ins);
1594         extent_io_tree_empty_lru(&BTRFS_I(fs_info->btree_inode)->io_tree);
1595
1596         truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
1597
1598         btrfs_stop_workers(&fs_info->workers);
1599         btrfs_stop_workers(&fs_info->endio_workers);
1600
1601         iput(fs_info->btree_inode);
1602 #if 0
1603         while(!list_empty(&fs_info->hashers)) {
1604                 struct btrfs_hasher *hasher;
1605                 hasher = list_entry(fs_info->hashers.next, struct btrfs_hasher,
1606                                     hashers);
1607                 list_del(&hasher->hashers);
1608                 crypto_free_hash(&fs_info->hash_tfm);
1609                 kfree(hasher);
1610         }
1611 #endif
1612         btrfs_close_devices(fs_info->fs_devices);
1613         btrfs_mapping_tree_free(&fs_info->mapping_tree);
1614
1615 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1616         bdi_destroy(&fs_info->bdi);
1617 #endif
1618
1619         kfree(fs_info->extent_root);
1620         kfree(fs_info->tree_root);
1621         kfree(fs_info->chunk_root);
1622         kfree(fs_info->dev_root);
1623         return 0;
1624 }
1625
1626 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
1627 {
1628         int ret;
1629         struct inode *btree_inode = buf->first_page->mapping->host;
1630
1631         ret = extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf);
1632         if (!ret)
1633                 return ret;
1634
1635         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
1636                                     parent_transid);
1637         return !ret;
1638 }
1639
1640 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
1641 {
1642         struct inode *btree_inode = buf->first_page->mapping->host;
1643         return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
1644                                           buf);
1645 }
1646
1647 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
1648 {
1649         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1650         u64 transid = btrfs_header_generation(buf);
1651         struct inode *btree_inode = root->fs_info->btree_inode;
1652
1653         if (transid != root->fs_info->generation) {
1654                 printk(KERN_CRIT "transid mismatch buffer %llu, found %Lu running %Lu\n",
1655                         (unsigned long long)buf->start,
1656                         transid, root->fs_info->generation);
1657                 WARN_ON(1);
1658         }
1659         set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree, buf);
1660 }
1661
1662 void btrfs_throttle(struct btrfs_root *root)
1663 {
1664         struct backing_dev_info *bdi;
1665
1666         bdi = &root->fs_info->bdi;
1667         if (root->fs_info->throttles && bdi_write_congested(bdi)) {
1668 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,18)
1669                 congestion_wait(WRITE, HZ/20);
1670 #else
1671                 blk_congestion_wait(WRITE, HZ/20);
1672 #endif
1673         }
1674 }
1675
1676 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
1677 {
1678         /*
1679          * looks as though older kernels can get into trouble with
1680          * this code, they end up stuck in balance_dirty_pages forever
1681          */
1682         struct extent_io_tree *tree;
1683         u64 num_dirty;
1684         u64 start = 0;
1685         unsigned long thresh = 16 * 1024 * 1024;
1686         tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
1687
1688         if (current_is_pdflush())
1689                 return;
1690
1691         num_dirty = count_range_bits(tree, &start, (u64)-1,
1692                                      thresh, EXTENT_DIRTY);
1693         if (num_dirty > thresh) {
1694                 balance_dirty_pages_ratelimited_nr(
1695                                    root->fs_info->btree_inode->i_mapping, 1);
1696         }
1697         return;
1698 }
1699
1700 void btrfs_set_buffer_defrag(struct extent_buffer *buf)
1701 {
1702         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1703         struct inode *btree_inode = root->fs_info->btree_inode;
1704         set_extent_bits(&BTRFS_I(btree_inode)->io_tree, buf->start,
1705                         buf->start + buf->len - 1, EXTENT_DEFRAG, GFP_NOFS);
1706 }
1707
1708 void btrfs_set_buffer_defrag_done(struct extent_buffer *buf)
1709 {
1710         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1711         struct inode *btree_inode = root->fs_info->btree_inode;
1712         set_extent_bits(&BTRFS_I(btree_inode)->io_tree, buf->start,
1713                         buf->start + buf->len - 1, EXTENT_DEFRAG_DONE,
1714                         GFP_NOFS);
1715 }
1716
1717 int btrfs_buffer_defrag(struct extent_buffer *buf)
1718 {
1719         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1720         struct inode *btree_inode = root->fs_info->btree_inode;
1721         return test_range_bit(&BTRFS_I(btree_inode)->io_tree,
1722                      buf->start, buf->start + buf->len - 1, EXTENT_DEFRAG, 0);
1723 }
1724
1725 int btrfs_buffer_defrag_done(struct extent_buffer *buf)
1726 {
1727         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1728         struct inode *btree_inode = root->fs_info->btree_inode;
1729         return test_range_bit(&BTRFS_I(btree_inode)->io_tree,
1730                      buf->start, buf->start + buf->len - 1,
1731                      EXTENT_DEFRAG_DONE, 0);
1732 }
1733
1734 int btrfs_clear_buffer_defrag_done(struct extent_buffer *buf)
1735 {
1736         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1737         struct inode *btree_inode = root->fs_info->btree_inode;
1738         return clear_extent_bits(&BTRFS_I(btree_inode)->io_tree,
1739                      buf->start, buf->start + buf->len - 1,
1740                      EXTENT_DEFRAG_DONE, GFP_NOFS);
1741 }
1742
1743 int btrfs_clear_buffer_defrag(struct extent_buffer *buf)
1744 {
1745         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1746         struct inode *btree_inode = root->fs_info->btree_inode;
1747         return clear_extent_bits(&BTRFS_I(btree_inode)->io_tree,
1748                      buf->start, buf->start + buf->len - 1,
1749                      EXTENT_DEFRAG, GFP_NOFS);
1750 }
1751
1752 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
1753 {
1754         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1755         int ret;
1756         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
1757         if (ret == 0) {
1758                 buf->flags |= EXTENT_UPTODATE;
1759         }
1760         return ret;
1761 }
1762
1763 static struct extent_io_ops btree_extent_io_ops = {
1764         .writepage_io_hook = btree_writepage_io_hook,
1765         .readpage_end_io_hook = btree_readpage_end_io_hook,
1766         .submit_bio_hook = btree_submit_bio_hook,
1767         /* note we're sharing with inode.c for the merge bio hook */
1768         .merge_bio_hook = btrfs_merge_bio_hook,
1769 };