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/version.h>
  20 #include <linux/fs.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/scatterlist.h>
  23 #include <linux/swap.h>
  24 #include <linux/radix-tree.h>
  25 #include <linux/writeback.h>
  26 #include <linux/buffer_head.h> // for block_sync_page
  27 #include <linux/workqueue.h>
  28 #include <linux/kthread.h>
  29 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20)
  30 # include <linux/freezer.h>
  31 #else
  32 # include <linux/sched.h>
  33 #endif
  34 #include "crc32c.h"
  35 #include "ctree.h"
  36 #include "disk-io.h"
  37 #include "transaction.h"
  38 #include "btrfs_inode.h"
  39 #include "volumes.h"
  40 #include "print-tree.h"
  41 #include "async-thread.h"
  42 #include "locking.h"
  43 #include "ref-cache.h"
  44
  45 #if 0
  46 static int check_tree_block(struct btrfs_root *root, struct extent_buffer *buf)
  47 {
  48         if (extent_buffer_blocknr(buf) != btrfs_header_blocknr(buf)) {
  49                 printk(KERN_CRIT "buf blocknr(buf) is %llu, header is %llu\n",
  50                        (unsigned long long)extent_buffer_blocknr(buf),
  51                        (unsigned long long)btrfs_header_blocknr(buf));
  52                 return 1;
  53         }
  54         return 0;
  55 }
  56 #endif
  57
  58 static struct extent_io_ops btree_extent_io_ops;
  59 static void end_workqueue_fn(struct btrfs_work *work);
  60
  61 struct end_io_wq {
  62         struct bio *bio;
  63         bio_end_io_t *end_io;
  64         void *private;
  65         struct btrfs_fs_info *info;
  66         int error;
  67         int metadata;
  68         struct list_head list;
  69         struct btrfs_work work;
  70 };
  71
  72 struct async_submit_bio {
  73         struct inode *inode;
  74         struct bio *bio;
  75         struct list_head list;
  76         extent_submit_bio_hook_t *submit_bio_hook;
  77         int rw;
  78         int mirror_num;
  79         struct btrfs_work work;
  80 };
  81
  82 struct extent_map *btree_get_extent(struct inode *inode, struct page *page,
  83                                     size_t page_offset, u64 start, u64 len,
  84                                     int create)
  85 {
  86         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
  87         struct extent_map *em;
  88         int ret;
  89
  90         spin_lock(&em_tree->lock);
  91         em = lookup_extent_mapping(em_tree, start, len);
  92         if (em) {
  93                 em->bdev =
  94                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
  95                 spin_unlock(&em_tree->lock);
  96                 goto out;
  97         }
  98         spin_unlock(&em_tree->lock);
  99
 100         em = alloc_extent_map(GFP_NOFS);
 101         if (!em) {
 102                 em = ERR_PTR(-ENOMEM);
 103                 goto out;
 104         }
 105         em->start = 0;
 106         em->len = (u64)-1;
 107         em->block_start = 0;
 108         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 109
 110         spin_lock(&em_tree->lock);
 111         ret = add_extent_mapping(em_tree, em);
 112         if (ret == -EEXIST) {
 113                 u64 failed_start = em->start;
 114                 u64 failed_len = em->len;
 115
 116                 printk("failed to insert %Lu %Lu -> %Lu into tree\n",
 117                        em->start, em->len, em->block_start);
 118                 free_extent_map(em);
 119                 em = lookup_extent_mapping(em_tree, start, len);
 120                 if (em) {
 121                         printk("after failing, found %Lu %Lu %Lu\n",
 122                                em->start, em->len, em->block_start);
 123                         ret = 0;
 124                 } else {
 125                         em = lookup_extent_mapping(em_tree, failed_start,
 126                                                    failed_len);
 127                         if (em) {
 128                                 printk("double failure lookup gives us "
 129                                        "%Lu %Lu -> %Lu\n", em->start,
 130                                        em->len, em->block_start);
 131                                 free_extent_map(em);
 132                         }
 133                         ret = -EIO;
 134                 }
 135         } else if (ret) {
 136                 free_extent_map(em);
 137                 em = NULL;
 138         }
 139         spin_unlock(&em_tree->lock);
 140
 141         if (ret)
 142                 em = ERR_PTR(ret);
 143 out:
 144         return em;
 145 }
 146
 147 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
 148 {
 149         return btrfs_crc32c(seed, data, len);
 150 }
 151
 152 void btrfs_csum_final(u32 crc, char *result)
 153 {
 154         *(__le32 *)result = ~cpu_to_le32(crc);
 155 }
 156
 157 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 158                            int verify)
 159 {
 160         char result[BTRFS_CRC32_SIZE];
 161         unsigned long len;
 162         unsigned long cur_len;
 163         unsigned long offset = BTRFS_CSUM_SIZE;
 164         char *map_token = NULL;
 165         char *kaddr;
 166         unsigned long map_start;
 167         unsigned long map_len;
 168         int err;
 169         u32 crc = ~(u32)0;
 170
 171         len = buf->len - offset;
 172         while(len > 0) {
 173                 err = map_private_extent_buffer(buf, offset, 32,
 174                                         &map_token, &kaddr,
 175                                         &map_start, &map_len, KM_USER0);
 176                 if (err) {
 177                         printk("failed to map extent buffer! %lu\n",
 178                                offset);
 179                         return 1;
 180                 }
 181                 cur_len = min(len, map_len - (offset - map_start));
 182                 crc = btrfs_csum_data(root, kaddr + offset - map_start,
 183                                       crc, cur_len);
 184                 len -= cur_len;
 185                 offset += cur_len;
 186                 unmap_extent_buffer(buf, map_token, KM_USER0);
 187         }
 188         btrfs_csum_final(crc, result);
 189
 190         if (verify) {
 191                 /* FIXME, this is not good */
 192                 if (memcmp_extent_buffer(buf, result, 0, BTRFS_CRC32_SIZE)) {
 193                         u32 val;
 194                         u32 found = 0;
 195                         memcpy(&found, result, BTRFS_CRC32_SIZE);
 196
 197                         read_extent_buffer(buf, &val, 0, BTRFS_CRC32_SIZE);
 198                         printk("btrfs: %s checksum verify failed on %llu "
 199                                "wanted %X found %X level %d\n",
 200                                root->fs_info->sb->s_id,
 201                                buf->start, val, found, 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         clear_extent_buffer_uptodate(io_tree, eb);
 230 out:
 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         found_start = btrfs_header_bytenr(eb);
 291         if (found_start != start) {
 292                 printk("warning: eb start incorrect %Lu buffer %Lu len %lu\n",
 293                        start, found_start, len);
 294                 WARN_ON(1);
 295                 goto err;
 296         }
 297         if (eb->first_page != page) {
 298                 printk("bad first page %lu %lu\n", eb->first_page->index,
 299                        page->index);
 300                 WARN_ON(1);
 301                 goto err;
 302         }
 303         if (!PageUptodate(page)) {
 304                 printk("csum not up to date page %lu\n", page->index);
 305                 WARN_ON(1);
 306                 goto err;
 307         }
 308         found_level = btrfs_header_level(eb);
 309         spin_lock(&root->fs_info->hash_lock);
 310         btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
 311         spin_unlock(&root->fs_info->hash_lock);
 312         csum_tree_block(root, eb, 0);
 313 err:
 314         free_extent_buffer(eb);
 315 out:
 316         return 0;
 317 }
 318
 319 static int btree_writepage_io_hook(struct page *page, u64 start, u64 end)
 320 {
 321         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 322
 323         csum_dirty_buffer(root, page);
 324         return 0;
 325 }
 326
 327 int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
 328                                struct extent_state *state)
 329 {
 330         struct extent_io_tree *tree;
 331         u64 found_start;
 332         int found_level;
 333         unsigned long len;
 334         struct extent_buffer *eb;
 335         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 336         int ret = 0;
 337
 338         tree = &BTRFS_I(page->mapping->host)->io_tree;
 339         if (page->private == EXTENT_PAGE_PRIVATE)
 340                 goto out;
 341         if (!page->private)
 342                 goto out;
 343         len = page->private >> 2;
 344         if (len == 0) {
 345                 WARN_ON(1);
 346         }
 347         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 348
 349         found_start = btrfs_header_bytenr(eb);
 350         if (found_start != start) {
 351                 ret = -EIO;
 352                 goto err;
 353         }
 354         if (eb->first_page != page) {
 355                 printk("bad first page %lu %lu\n", eb->first_page->index,
 356                        page->index);
 357                 WARN_ON(1);
 358                 ret = -EIO;
 359                 goto err;
 360         }
 361         if (memcmp_extent_buffer(eb, root->fs_info->fsid,
 362                                  (unsigned long)btrfs_header_fsid(eb),
 363                                  BTRFS_FSID_SIZE)) {
 364                 printk("bad fsid on block %Lu\n", eb->start);
 365                 ret = -EIO;
 366                 goto err;
 367         }
 368         found_level = btrfs_header_level(eb);
 369
 370         ret = csum_tree_block(root, eb, 1);
 371         if (ret)
 372                 ret = -EIO;
 373
 374         end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
 375         end = eb->start + end - 1;
 376 err:
 377         free_extent_buffer(eb);
 378 out:
 379         return ret;
 380 }
 381
 382 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
 383 static void end_workqueue_bio(struct bio *bio, int err)
 384 #else
 385 static int end_workqueue_bio(struct bio *bio,
 386                                    unsigned int bytes_done, int err)
 387 #endif
 388 {
 389         struct end_io_wq *end_io_wq = bio->bi_private;
 390         struct btrfs_fs_info *fs_info;
 391
 392 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
 393         if (bio->bi_size)
 394                 return 1;
 395 #endif
 396
 397         fs_info = end_io_wq->info;
 398         end_io_wq->error = err;
 399         end_io_wq->work.func = end_workqueue_fn;
 400         end_io_wq->work.flags = 0;
 401         if (bio->bi_rw & (1 << BIO_RW))
 402                 btrfs_queue_worker(&fs_info->endio_write_workers,
 403                                    &end_io_wq->work);
 404         else
 405                 btrfs_queue_worker(&fs_info->endio_workers, &end_io_wq->work);
 406
 407 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
 408         return 0;
 409 #endif
 410 }
 411
 412 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 413                         int metadata)
 414 {
 415         struct end_io_wq *end_io_wq;
 416         end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
 417         if (!end_io_wq)
 418                 return -ENOMEM;
 419
 420         end_io_wq->private = bio->bi_private;
 421         end_io_wq->end_io = bio->bi_end_io;
 422         end_io_wq->info = info;
 423         end_io_wq->error = 0;
 424         end_io_wq->bio = bio;
 425         end_io_wq->metadata = metadata;
 426
 427         bio->bi_private = end_io_wq;
 428         bio->bi_end_io = end_workqueue_bio;
 429         return 0;
 430 }
 431
 432 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
 433 {
 434         unsigned long limit = min_t(unsigned long,
 435                                     info->workers.max_workers,
 436                                     info->fs_devices->open_devices);
 437         return 256 * limit;
 438 }
 439
 440 int btrfs_congested_async(struct btrfs_fs_info *info, int iodone)
 441 {
 442         return atomic_read(&info->nr_async_bios) >
 443                 btrfs_async_submit_limit(info);
 444 }
 445
 446 static void run_one_async_submit(struct btrfs_work *work)
 447 {
 448         struct btrfs_fs_info *fs_info;
 449         struct async_submit_bio *async;
 450         int limit;
 451
 452         async = container_of(work, struct  async_submit_bio, work);
 453         fs_info = BTRFS_I(async->inode)->root->fs_info;
 454
 455         limit = btrfs_async_submit_limit(fs_info);
 456         limit = limit * 2 / 3;
 457
 458         atomic_dec(&fs_info->nr_async_submits);
 459
 460         if (atomic_read(&fs_info->nr_async_submits) < limit &&
 461             waitqueue_active(&fs_info->async_submit_wait))
 462                 wake_up(&fs_info->async_submit_wait);
 463
 464         async->submit_bio_hook(async->inode, async->rw, async->bio,
 465                                async->mirror_num);
 466         kfree(async);
 467 }
 468
 469 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
 470                         int rw, struct bio *bio, int mirror_num,
 471                         extent_submit_bio_hook_t *submit_bio_hook)
 472 {
 473         struct async_submit_bio *async;
 474         int limit = btrfs_async_submit_limit(fs_info);
 475
 476         async = kmalloc(sizeof(*async), GFP_NOFS);
 477         if (!async)
 478                 return -ENOMEM;
 479
 480         async->inode = inode;
 481         async->rw = rw;
 482         async->bio = bio;
 483         async->mirror_num = mirror_num;
 484         async->submit_bio_hook = submit_bio_hook;
 485         async->work.func = run_one_async_submit;
 486         async->work.flags = 0;
 487         atomic_inc(&fs_info->nr_async_submits);
 488         btrfs_queue_worker(&fs_info->workers, &async->work);
 489
 490         wait_event_timeout(fs_info->async_submit_wait,
 491                            (atomic_read(&fs_info->nr_async_submits) < limit),
 492                            HZ/10);
 493         return 0;
 494 }
 495
 496 static int __btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 497                                  int mirror_num)
 498 {
 499         struct btrfs_root *root = BTRFS_I(inode)->root;
 500         u64 offset;
 501         int ret;
 502
 503         offset = bio->bi_sector << 9;
 504
 505         /*
 506          * when we're called for a write, we're already in the async
 507          * submission context.  Just jump into btrfs_map_bio
 508          */
 509         if (rw & (1 << BIO_RW)) {
 510                 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
 511                                      mirror_num, 1);
 512         }
 513
 514         /*
 515          * called for a read, do the setup so that checksum validation
 516          * can happen in the async kernel threads
 517          */
 518         ret = btrfs_bio_wq_end_io(root->fs_info, bio, 1);
 519         BUG_ON(ret);
 520
 521         return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
 522 }
 523
 524 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 525                                  int mirror_num)
 526 {
 527         /*
 528          * kthread helpers are used to submit writes so that checksumming
 529          * can happen in parallel across all CPUs
 530          */
 531         if (!(rw & (1 << BIO_RW))) {
 532                 return __btree_submit_bio_hook(inode, rw, bio, mirror_num);
 533         }
 534         return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
 535                                    inode, rw, bio, mirror_num,
 536                                    __btree_submit_bio_hook);
 537 }
 538
 539 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 540 {
 541         struct extent_io_tree *tree;
 542         tree = &BTRFS_I(page->mapping->host)->io_tree;
 543
 544         if (current->flags & PF_MEMALLOC) {
 545                 redirty_page_for_writepage(wbc, page);
 546                 unlock_page(page);
 547                 return 0;
 548         }
 549         return extent_write_full_page(tree, page, btree_get_extent, wbc);
 550 }
 551
 552 static int btree_writepages(struct address_space *mapping,
 553                             struct writeback_control *wbc)
 554 {
 555         struct extent_io_tree *tree;
 556         tree = &BTRFS_I(mapping->host)->io_tree;
 557         if (wbc->sync_mode == WB_SYNC_NONE) {
 558                 u64 num_dirty;
 559                 u64 start = 0;
 560                 unsigned long thresh = 8 * 1024 * 1024;
 561
 562                 if (wbc->for_kupdate)
 563                         return 0;
 564
 565                 num_dirty = count_range_bits(tree, &start, (u64)-1,
 566                                              thresh, EXTENT_DIRTY);
 567                 if (num_dirty < thresh) {
 568                         return 0;
 569                 }
 570         }
 571         return extent_writepages(tree, mapping, btree_get_extent, wbc);
 572 }
 573
 574 int btree_readpage(struct file *file, struct page *page)
 575 {
 576         struct extent_io_tree *tree;
 577         tree = &BTRFS_I(page->mapping->host)->io_tree;
 578         return extent_read_full_page(tree, page, btree_get_extent);
 579 }
 580
 581 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
 582 {
 583         struct extent_io_tree *tree;
 584         struct extent_map_tree *map;
 585         int ret;
 586
 587         tree = &BTRFS_I(page->mapping->host)->io_tree;
 588         map = &BTRFS_I(page->mapping->host)->extent_tree;
 589
 590         ret = try_release_extent_state(map, tree, page, gfp_flags);
 591         if (!ret) {
 592                 return 0;
 593         }
 594
 595         ret = try_release_extent_buffer(tree, page);
 596         if (ret == 1) {
 597                 ClearPagePrivate(page);
 598                 set_page_private(page, 0);
 599                 page_cache_release(page);
 600         }
 601
 602         return ret;
 603 }
 604
 605 static void btree_invalidatepage(struct page *page, unsigned long offset)
 606 {
 607         struct extent_io_tree *tree;
 608         tree = &BTRFS_I(page->mapping->host)->io_tree;
 609         extent_invalidatepage(tree, page, offset);
 610         btree_releasepage(page, GFP_NOFS);
 611         if (PagePrivate(page)) {
 612                 printk("warning page private not zero on page %Lu\n",
 613                        page_offset(page));
 614                 ClearPagePrivate(page);
 615                 set_page_private(page, 0);
 616                 page_cache_release(page);
 617         }
 618 }
 619
 620 #if 0
 621 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 622 {
 623         struct buffer_head *bh;
 624         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 625         struct buffer_head *head;
 626         if (!page_has_buffers(page)) {
 627                 create_empty_buffers(page, root->fs_info->sb->s_blocksize,
 628                                         (1 << BH_Dirty)|(1 << BH_Uptodate));
 629         }
 630         head = page_buffers(page);
 631         bh = head;
 632         do {
 633                 if (buffer_dirty(bh))
 634                         csum_tree_block(root, bh, 0);
 635                 bh = bh->b_this_page;
 636         } while (bh != head);
 637         return block_write_full_page(page, btree_get_block, wbc);
 638 }
 639 #endif
 640
 641 static struct address_space_operations btree_aops = {
 642         .readpage       = btree_readpage,
 643         .writepage      = btree_writepage,
 644         .writepages     = btree_writepages,
 645         .releasepage    = btree_releasepage,
 646         .invalidatepage = btree_invalidatepage,
 647         .sync_page      = block_sync_page,
 648 };
 649
 650 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
 651                          u64 parent_transid)
 652 {
 653         struct extent_buffer *buf = NULL;
 654         struct inode *btree_inode = root->fs_info->btree_inode;
 655         int ret = 0;
 656
 657         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 658         if (!buf)
 659                 return 0;
 660         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
 661                                  buf, 0, 0, btree_get_extent, 0);
 662         free_extent_buffer(buf);
 663         return ret;
 664 }
 665
 666 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
 667                                             u64 bytenr, u32 blocksize)
 668 {
 669         struct inode *btree_inode = root->fs_info->btree_inode;
 670         struct extent_buffer *eb;
 671         eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 672                                 bytenr, blocksize, GFP_NOFS);
 673         return eb;
 674 }
 675
 676 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 677                                                  u64 bytenr, u32 blocksize)
 678 {
 679         struct inode *btree_inode = root->fs_info->btree_inode;
 680         struct extent_buffer *eb;
 681
 682         eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 683                                  bytenr, blocksize, NULL, GFP_NOFS);
 684         return eb;
 685 }
 686
 687
 688 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 689                                       u32 blocksize, u64 parent_transid)
 690 {
 691         struct extent_buffer *buf = NULL;
 692         struct inode *btree_inode = root->fs_info->btree_inode;
 693         struct extent_io_tree *io_tree;
 694         int ret;
 695
 696         io_tree = &BTRFS_I(btree_inode)->io_tree;
 697
 698         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 699         if (!buf)
 700                 return NULL;
 701
 702         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
 703
 704         if (ret == 0) {
 705                 buf->flags |= EXTENT_UPTODATE;
 706         }
 707         return buf;
 708
 709 }
 710
 711 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 712                      struct extent_buffer *buf)
 713 {
 714         struct inode *btree_inode = root->fs_info->btree_inode;
 715         if (btrfs_header_generation(buf) ==
 716             root->fs_info->running_transaction->transid) {
 717                 WARN_ON(!btrfs_tree_locked(buf));
 718                 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
 719                                           buf);
 720         }
 721         return 0;
 722 }
 723
 724 int wait_on_tree_block_writeback(struct btrfs_root *root,
 725                                  struct extent_buffer *buf)
 726 {
 727         struct inode *btree_inode = root->fs_info->btree_inode;
 728         wait_on_extent_buffer_writeback(&BTRFS_I(btree_inode)->io_tree,
 729                                         buf);
 730         return 0;
 731 }
 732
 733 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
 734                         u32 stripesize, struct btrfs_root *root,
 735                         struct btrfs_fs_info *fs_info,
 736                         u64 objectid)
 737 {
 738         root->node = NULL;
 739         root->inode = NULL;
 740         root->commit_root = NULL;
 741         root->ref_tree = NULL;
 742         root->sectorsize = sectorsize;
 743         root->nodesize = nodesize;
 744         root->leafsize = leafsize;
 745         root->stripesize = stripesize;
 746         root->ref_cows = 0;
 747         root->track_dirty = 0;
 748
 749         root->fs_info = fs_info;
 750         root->objectid = objectid;
 751         root->last_trans = 0;
 752         root->highest_inode = 0;
 753         root->last_inode_alloc = 0;
 754         root->name = NULL;
 755         root->in_sysfs = 0;
 756
 757         INIT_LIST_HEAD(&root->dirty_list);
 758         INIT_LIST_HEAD(&root->orphan_list);
 759         INIT_LIST_HEAD(&root->dead_list);
 760         spin_lock_init(&root->node_lock);
 761         spin_lock_init(&root->list_lock);
 762         mutex_init(&root->objectid_mutex);
 763
 764         btrfs_leaf_ref_tree_init(&root->ref_tree_struct);
 765         root->ref_tree = &root->ref_tree_struct;
 766
 767         memset(&root->root_key, 0, sizeof(root->root_key));
 768         memset(&root->root_item, 0, sizeof(root->root_item));
 769         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
 770         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
 771         root->defrag_trans_start = fs_info->generation;
 772         init_completion(&root->kobj_unregister);
 773         root->defrag_running = 0;
 774         root->defrag_level = 0;
 775         root->root_key.objectid = objectid;
 776         return 0;
 777 }
 778
 779 static int find_and_setup_root(struct btrfs_root *tree_root,
 780                                struct btrfs_fs_info *fs_info,
 781                                u64 objectid,
 782                                struct btrfs_root *root)
 783 {
 784         int ret;
 785         u32 blocksize;
 786
 787         __setup_root(tree_root->nodesize, tree_root->leafsize,
 788                      tree_root->sectorsize, tree_root->stripesize,
 789                      root, fs_info, objectid);
 790         ret = btrfs_find_last_root(tree_root, objectid,
 791                                    &root->root_item, &root->root_key);
 792         BUG_ON(ret);
 793
 794         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
 795         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
 796                                      blocksize, 0);
 797         BUG_ON(!root->node);
 798         return 0;
 799 }
 800
 801 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_fs_info *fs_info,
 802                                                struct btrfs_key *location)
 803 {
 804         struct btrfs_root *root;
 805         struct btrfs_root *tree_root = fs_info->tree_root;
 806         struct btrfs_path *path;
 807         struct extent_buffer *l;
 808         u64 highest_inode;
 809         u32 blocksize;
 810         int ret = 0;
 811
 812         root = kzalloc(sizeof(*root), GFP_NOFS);
 813         if (!root)
 814                 return ERR_PTR(-ENOMEM);
 815         if (location->offset == (u64)-1) {
 816                 ret = find_and_setup_root(tree_root, fs_info,
 817                                           location->objectid, root);
 818                 if (ret) {
 819                         kfree(root);
 820                         return ERR_PTR(ret);
 821                 }
 822                 goto insert;
 823         }
 824
 825         __setup_root(tree_root->nodesize, tree_root->leafsize,
 826                      tree_root->sectorsize, tree_root->stripesize,
 827                      root, fs_info, location->objectid);
 828
 829         path = btrfs_alloc_path();
 830         BUG_ON(!path);
 831         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
 832         if (ret != 0) {
 833                 if (ret > 0)
 834                         ret = -ENOENT;
 835                 goto out;
 836         }
 837         l = path->nodes[0];
 838         read_extent_buffer(l, &root->root_item,
 839                btrfs_item_ptr_offset(l, path->slots[0]),
 840                sizeof(root->root_item));
 841         memcpy(&root->root_key, location, sizeof(*location));
 842         ret = 0;
 843 out:
 844         btrfs_release_path(root, path);
 845         btrfs_free_path(path);
 846         if (ret) {
 847                 kfree(root);
 848                 return ERR_PTR(ret);
 849         }
 850         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
 851         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
 852                                      blocksize, 0);
 853         BUG_ON(!root->node);
 854 insert:
 855         root->ref_cows = 1;
 856         ret = btrfs_find_highest_inode(root, &highest_inode);
 857         if (ret == 0) {
 858                 root->highest_inode = highest_inode;
 859                 root->last_inode_alloc = highest_inode;
 860         }
 861         return root;
 862 }
 863
 864 struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
 865                                         u64 root_objectid)
 866 {
 867         struct btrfs_root *root;
 868
 869         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID)
 870                 return fs_info->tree_root;
 871         if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID)
 872                 return fs_info->extent_root;
 873
 874         root = radix_tree_lookup(&fs_info->fs_roots_radix,
 875                                  (unsigned long)root_objectid);
 876         return root;
 877 }
 878
 879 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
 880                                               struct btrfs_key *location)
 881 {
 882         struct btrfs_root *root;
 883         int ret;
 884
 885         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
 886                 return fs_info->tree_root;
 887         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
 888                 return fs_info->extent_root;
 889         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
 890                 return fs_info->chunk_root;
 891         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
 892                 return fs_info->dev_root;
 893
 894         root = radix_tree_lookup(&fs_info->fs_roots_radix,
 895                                  (unsigned long)location->objectid);
 896         if (root)
 897                 return root;
 898
 899         root = btrfs_read_fs_root_no_radix(fs_info, location);
 900         if (IS_ERR(root))
 901                 return root;
 902         ret = radix_tree_insert(&fs_info->fs_roots_radix,
 903                                 (unsigned long)root->root_key.objectid,
 904                                 root);
 905         if (ret) {
 906                 free_extent_buffer(root->node);
 907                 kfree(root);
 908                 return ERR_PTR(ret);
 909         }
 910         ret = btrfs_find_dead_roots(fs_info->tree_root,
 911                                     root->root_key.objectid, root);
 912         BUG_ON(ret);
 913
 914         return root;
 915 }
 916
 917 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 918                                       struct btrfs_key *location,
 919                                       const char *name, int namelen)
 920 {
 921         struct btrfs_root *root;
 922         int ret;
 923
 924         root = btrfs_read_fs_root_no_name(fs_info, location);
 925         if (!root)
 926                 return NULL;
 927
 928         if (root->in_sysfs)
 929                 return root;
 930
 931         ret = btrfs_set_root_name(root, name, namelen);
 932         if (ret) {
 933                 free_extent_buffer(root->node);
 934                 kfree(root);
 935                 return ERR_PTR(ret);
 936         }
 937
 938         ret = btrfs_sysfs_add_root(root);
 939         if (ret) {
 940                 free_extent_buffer(root->node);
 941                 kfree(root->name);
 942                 kfree(root);
 943                 return ERR_PTR(ret);
 944         }
 945         root->in_sysfs = 1;
 946         return root;
 947 }
 948 #if 0
 949 static int add_hasher(struct btrfs_fs_info *info, char *type) {
 950         struct btrfs_hasher *hasher;
 951
 952         hasher = kmalloc(sizeof(*hasher), GFP_NOFS);
 953         if (!hasher)
 954                 return -ENOMEM;
 955         hasher->hash_tfm = crypto_alloc_hash(type, 0, CRYPTO_ALG_ASYNC);
 956         if (!hasher->hash_tfm) {
 957                 kfree(hasher);
 958                 return -EINVAL;
 959         }
 960         spin_lock(&info->hash_lock);
 961         list_add(&hasher->list, &info->hashers);
 962         spin_unlock(&info->hash_lock);
 963         return 0;
 964 }
 965 #endif
 966
 967 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
 968 {
 969         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
 970         int ret = 0;
 971         struct list_head *cur;
 972         struct btrfs_device *device;
 973         struct backing_dev_info *bdi;
 974
 975         if ((bdi_bits & (1 << BDI_write_congested)) &&
 976             btrfs_congested_async(info, 0))
 977                 return 1;
 978
 979         list_for_each(cur, &info->fs_devices->devices) {
 980                 device = list_entry(cur, struct btrfs_device, dev_list);
 981                 if (!device->bdev)
 982                         continue;
 983                 bdi = blk_get_backing_dev_info(device->bdev);
 984                 if (bdi && bdi_congested(bdi, bdi_bits)) {
 985                         ret = 1;
 986                         break;
 987                 }
 988         }
 989         return ret;
 990 }
 991
 992 /*
 993  * this unplugs every device on the box, and it is only used when page
 994  * is null
 995  */
 996 static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
 997 {
 998         struct list_head *cur;
 999         struct btrfs_device *device;
1000         struct btrfs_fs_info *info;
1001
1002         info = (struct btrfs_fs_info *)bdi->unplug_io_data;
1003         list_for_each(cur, &info->fs_devices->devices) {
1004                 device = list_entry(cur, struct btrfs_device, dev_list);
1005                 bdi = blk_get_backing_dev_info(device->bdev);
1006                 if (bdi->unplug_io_fn) {
1007                         bdi->unplug_io_fn(bdi, page);
1008                 }
1009         }
1010 }
1011
1012 void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1013 {
1014         struct inode *inode;
1015         struct extent_map_tree *em_tree;
1016         struct extent_map *em;
1017         struct address_space *mapping;
1018         u64 offset;
1019
1020         /* the generic O_DIRECT read code does this */
1021         if (!page) {
1022                 __unplug_io_fn(bdi, page);
1023                 return;
1024         }
1025
1026         /*
1027          * page->mapping may change at any time.  Get a consistent copy
1028          * and use that for everything below
1029          */
1030         smp_mb();
1031         mapping = page->mapping;
1032         if (!mapping)
1033                 return;
1034
1035         inode = mapping->host;
1036         offset = page_offset(page);
1037
1038         em_tree = &BTRFS_I(inode)->extent_tree;
1039         spin_lock(&em_tree->lock);
1040         em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
1041         spin_unlock(&em_tree->lock);
1042         if (!em) {
1043                 __unplug_io_fn(bdi, page);
1044                 return;
1045         }
1046
1047         if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1048                 free_extent_map(em);
1049                 __unplug_io_fn(bdi, page);
1050                 return;
1051         }
1052         offset = offset - em->start;
1053         btrfs_unplug_page(&BTRFS_I(inode)->root->fs_info->mapping_tree,
1054                           em->block_start + offset, page);
1055         free_extent_map(em);
1056 }
1057
1058 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1059 {
1060 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1061         bdi_init(bdi);
1062 #endif
1063         bdi->ra_pages   = default_backing_dev_info.ra_pages;
1064         bdi->state              = 0;
1065         bdi->capabilities       = default_backing_dev_info.capabilities;
1066         bdi->unplug_io_fn       = btrfs_unplug_io_fn;
1067         bdi->unplug_io_data     = info;
1068         bdi->congested_fn       = btrfs_congested_fn;
1069         bdi->congested_data     = info;
1070         return 0;
1071 }
1072
1073 static int bio_ready_for_csum(struct bio *bio)
1074 {
1075         u64 length = 0;
1076         u64 buf_len = 0;
1077         u64 start = 0;
1078         struct page *page;
1079         struct extent_io_tree *io_tree = NULL;
1080         struct btrfs_fs_info *info = NULL;
1081         struct bio_vec *bvec;
1082         int i;
1083         int ret;
1084
1085         bio_for_each_segment(bvec, bio, i) {
1086                 page = bvec->bv_page;
1087                 if (page->private == EXTENT_PAGE_PRIVATE) {
1088                         length += bvec->bv_len;
1089                         continue;
1090                 }
1091                 if (!page->private) {
1092                         length += bvec->bv_len;
1093                         continue;
1094                 }
1095                 length = bvec->bv_len;
1096                 buf_len = page->private >> 2;
1097                 start = page_offset(page) + bvec->bv_offset;
1098                 io_tree = &BTRFS_I(page->mapping->host)->io_tree;
1099                 info = BTRFS_I(page->mapping->host)->root->fs_info;
1100         }
1101         /* are we fully contained in this bio? */
1102         if (buf_len <= length)
1103                 return 1;
1104
1105         ret = extent_range_uptodate(io_tree, start + length,
1106                                     start + buf_len - 1);
1107         if (ret == 1)
1108                 return ret;
1109         return ret;
1110 }
1111
1112 /*
1113  * called by the kthread helper functions to finally call the bio end_io
1114  * functions.  This is where read checksum verification actually happens
1115  */
1116 static void end_workqueue_fn(struct btrfs_work *work)
1117 {
1118         struct bio *bio;
1119         struct end_io_wq *end_io_wq;
1120         struct btrfs_fs_info *fs_info;
1121         int error;
1122
1123         end_io_wq = container_of(work, struct end_io_wq, work);
1124         bio = end_io_wq->bio;
1125         fs_info = end_io_wq->info;
1126
1127         /* metadata bios are special because the whole tree block must
1128          * be checksummed at once.  This makes sure the entire block is in
1129          * ram and up to date before trying to verify things.  For
1130          * blocksize <= pagesize, it is basically a noop
1131          */
1132         if (end_io_wq->metadata && !bio_ready_for_csum(bio)) {
1133                 btrfs_queue_worker(&fs_info->endio_workers,
1134                                    &end_io_wq->work);
1135                 return;
1136         }
1137         error = end_io_wq->error;
1138         bio->bi_private = end_io_wq->private;
1139         bio->bi_end_io = end_io_wq->end_io;
1140         kfree(end_io_wq);
1141 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1142         bio_endio(bio, bio->bi_size, error);
1143 #else
1144         bio_endio(bio, error);
1145 #endif
1146 }
1147
1148 static int cleaner_kthread(void *arg)
1149 {
1150         struct btrfs_root *root = arg;
1151
1152         do {
1153                 smp_mb();
1154                 if (root->fs_info->closing)
1155                         break;
1156
1157                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1158                 mutex_lock(&root->fs_info->cleaner_mutex);
1159                 btrfs_clean_old_snapshots(root);
1160                 mutex_unlock(&root->fs_info->cleaner_mutex);
1161
1162                 if (freezing(current)) {
1163                         refrigerator();
1164                 } else {
1165                         smp_mb();
1166                         if (root->fs_info->closing)
1167                                 break;
1168                         set_current_state(TASK_INTERRUPTIBLE);
1169                         schedule();
1170                         __set_current_state(TASK_RUNNING);
1171                 }
1172         } while (!kthread_should_stop());
1173         return 0;
1174 }
1175
1176 static int transaction_kthread(void *arg)
1177 {
1178         struct btrfs_root *root = arg;
1179         struct btrfs_trans_handle *trans;
1180         struct btrfs_transaction *cur;
1181         unsigned long now;
1182         unsigned long delay;
1183         int ret;
1184
1185         do {
1186                 smp_mb();
1187                 if (root->fs_info->closing)
1188                         break;
1189
1190                 delay = HZ * 30;
1191                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1192                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1193
1194                 if (root->fs_info->total_ref_cache_size > 20 * 1024 * 1024) {
1195                         printk("btrfs: total reference cache size %Lu\n",
1196                                 root->fs_info->total_ref_cache_size);
1197                 }
1198
1199                 mutex_lock(&root->fs_info->trans_mutex);
1200                 cur = root->fs_info->running_transaction;
1201                 if (!cur) {
1202                         mutex_unlock(&root->fs_info->trans_mutex);
1203                         goto sleep;
1204                 }
1205
1206                 now = get_seconds();
1207                 if (now < cur->start_time || now - cur->start_time < 30) {
1208                         mutex_unlock(&root->fs_info->trans_mutex);
1209                         delay = HZ * 5;
1210                         goto sleep;
1211                 }
1212                 mutex_unlock(&root->fs_info->trans_mutex);
1213                 trans = btrfs_start_transaction(root, 1);
1214                 ret = btrfs_commit_transaction(trans, root);
1215 sleep:
1216                 wake_up_process(root->fs_info->cleaner_kthread);
1217                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1218
1219                 if (freezing(current)) {
1220                         refrigerator();
1221                 } else {
1222                         if (root->fs_info->closing)
1223                                 break;
1224                         set_current_state(TASK_INTERRUPTIBLE);
1225                         schedule_timeout(delay);
1226                         __set_current_state(TASK_RUNNING);
1227                 }
1228         } while (!kthread_should_stop());
1229         return 0;
1230 }
1231
1232 struct btrfs_root *open_ctree(struct super_block *sb,
1233                               struct btrfs_fs_devices *fs_devices,
1234                               char *options)
1235 {
1236         u32 sectorsize;
1237         u32 nodesize;
1238         u32 leafsize;
1239         u32 blocksize;
1240         u32 stripesize;
1241         struct buffer_head *bh;
1242         struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
1243                                                  GFP_NOFS);
1244         struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
1245                                                GFP_NOFS);
1246         struct btrfs_fs_info *fs_info = kzalloc(sizeof(*fs_info),
1247                                                 GFP_NOFS);
1248         struct btrfs_root *chunk_root = kmalloc(sizeof(struct btrfs_root),
1249                                                 GFP_NOFS);
1250         struct btrfs_root *dev_root = kmalloc(sizeof(struct btrfs_root),
1251                                               GFP_NOFS);
1252         int ret;
1253         int err = -EINVAL;
1254
1255         struct btrfs_super_block *disk_super;
1256
1257         if (!extent_root || !tree_root || !fs_info) {
1258                 err = -ENOMEM;
1259                 goto fail;
1260         }
1261         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
1262         INIT_LIST_HEAD(&fs_info->trans_list);
1263         INIT_LIST_HEAD(&fs_info->dead_roots);
1264         INIT_LIST_HEAD(&fs_info->hashers);
1265         INIT_LIST_HEAD(&fs_info->delalloc_inodes);
1266         spin_lock_init(&fs_info->hash_lock);
1267         spin_lock_init(&fs_info->delalloc_lock);
1268         spin_lock_init(&fs_info->new_trans_lock);
1269         spin_lock_init(&fs_info->ref_cache_lock);
1270
1271         init_completion(&fs_info->kobj_unregister);
1272         fs_info->tree_root = tree_root;
1273         fs_info->extent_root = extent_root;
1274         fs_info->chunk_root = chunk_root;
1275         fs_info->dev_root = dev_root;
1276         fs_info->fs_devices = fs_devices;
1277         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
1278         INIT_LIST_HEAD(&fs_info->space_info);
1279         btrfs_mapping_init(&fs_info->mapping_tree);
1280         atomic_set(&fs_info->nr_async_submits, 0);
1281         atomic_set(&fs_info->nr_async_bios, 0);
1282         atomic_set(&fs_info->throttles, 0);
1283         atomic_set(&fs_info->throttle_gen, 0);
1284         fs_info->sb = sb;
1285         fs_info->max_extent = (u64)-1;
1286         fs_info->max_inline = 8192 * 1024;
1287         setup_bdi(fs_info, &fs_info->bdi);
1288         fs_info->btree_inode = new_inode(sb);
1289         fs_info->btree_inode->i_ino = 1;
1290         fs_info->btree_inode->i_nlink = 1;
1291         fs_info->thread_pool_size = min(num_online_cpus() + 2, 8);
1292
1293         INIT_LIST_HEAD(&fs_info->ordered_extents);
1294         spin_lock_init(&fs_info->ordered_extent_lock);
1295
1296         sb->s_blocksize = 4096;
1297         sb->s_blocksize_bits = blksize_bits(4096);
1298
1299         /*
1300          * we set the i_size on the btree inode to the max possible int.
1301          * the real end of the address space is determined by all of
1302          * the devices in the system
1303          */
1304         fs_info->btree_inode->i_size = OFFSET_MAX;
1305         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
1306         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
1307
1308         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
1309                              fs_info->btree_inode->i_mapping,
1310                              GFP_NOFS);
1311         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree,
1312                              GFP_NOFS);
1313
1314         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
1315
1316         extent_io_tree_init(&fs_info->free_space_cache,
1317                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1318         extent_io_tree_init(&fs_info->block_group_cache,
1319                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1320         extent_io_tree_init(&fs_info->pinned_extents,
1321                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1322         extent_io_tree_init(&fs_info->pending_del,
1323                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1324         extent_io_tree_init(&fs_info->extent_ins,
1325                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1326         fs_info->do_barriers = 1;
1327
1328         BTRFS_I(fs_info->btree_inode)->root = tree_root;
1329         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
1330                sizeof(struct btrfs_key));
1331         insert_inode_hash(fs_info->btree_inode);
1332         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
1333
1334         mutex_init(&fs_info->trans_mutex);
1335         mutex_init(&fs_info->drop_mutex);
1336         mutex_init(&fs_info->alloc_mutex);
1337         mutex_init(&fs_info->chunk_mutex);
1338         mutex_init(&fs_info->transaction_kthread_mutex);
1339         mutex_init(&fs_info->cleaner_mutex);
1340         mutex_init(&fs_info->volume_mutex);
1341         init_waitqueue_head(&fs_info->transaction_throttle);
1342         init_waitqueue_head(&fs_info->transaction_wait);
1343         init_waitqueue_head(&fs_info->async_submit_wait);
1344
1345 #if 0
1346         ret = add_hasher(fs_info, "crc32c");
1347         if (ret) {
1348                 printk("btrfs: failed hash setup, modprobe cryptomgr?\n");
1349                 err = -ENOMEM;
1350                 goto fail_iput;
1351         }
1352 #endif
1353         __setup_root(4096, 4096, 4096, 4096, tree_root,
1354                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
1355
1356
1357         bh = __bread(fs_devices->latest_bdev,
1358                      BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
1359         if (!bh)
1360                 goto fail_iput;
1361
1362         memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));
1363         brelse(bh);
1364
1365         memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
1366
1367         disk_super = &fs_info->super_copy;
1368         if (!btrfs_super_root(disk_super))
1369                 goto fail_sb_buffer;
1370
1371         err = btrfs_parse_options(tree_root, options);
1372         if (err)
1373                 goto fail_sb_buffer;
1374
1375         /*
1376          * we need to start all the end_io workers up front because the
1377          * queue work function gets called at interrupt time, and so it
1378          * cannot dynamically grow.
1379          */
1380         btrfs_init_workers(&fs_info->workers, "worker",
1381                            fs_info->thread_pool_size);
1382         btrfs_init_workers(&fs_info->submit_workers, "submit",
1383                            min_t(u64, fs_devices->num_devices,
1384                            fs_info->thread_pool_size));
1385
1386         /* a higher idle thresh on the submit workers makes it much more
1387          * likely that bios will be send down in a sane order to the
1388          * devices
1389          */
1390         fs_info->submit_workers.idle_thresh = 64;
1391
1392         /* fs_info->workers is responsible for checksumming file data
1393          * blocks and metadata.  Using a larger idle thresh allows each
1394          * worker thread to operate on things in roughly the order they
1395          * were sent by the writeback daemons, improving overall locality
1396          * of the IO going down the pipe.
1397          */
1398         fs_info->workers.idle_thresh = 128;
1399
1400         btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1);
1401         btrfs_init_workers(&fs_info->endio_workers, "endio",
1402                            fs_info->thread_pool_size);
1403         btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
1404                            fs_info->thread_pool_size);
1405
1406         /*
1407          * endios are largely parallel and should have a very
1408          * low idle thresh
1409          */
1410         fs_info->endio_workers.idle_thresh = 4;
1411         fs_info->endio_write_workers.idle_thresh = 4;
1412
1413         btrfs_start_workers(&fs_info->workers, 1);
1414         btrfs_start_workers(&fs_info->submit_workers, 1);
1415         btrfs_start_workers(&fs_info->fixup_workers, 1);
1416         btrfs_start_workers(&fs_info->endio_workers, fs_info->thread_pool_size);
1417         btrfs_start_workers(&fs_info->endio_write_workers,
1418                             fs_info->thread_pool_size);
1419
1420         err = -EINVAL;
1421         if (btrfs_super_num_devices(disk_super) > fs_devices->open_devices) {
1422                 printk("Btrfs: wanted %llu devices, but found %llu\n",
1423                        (unsigned long long)btrfs_super_num_devices(disk_super),
1424                        (unsigned long long)fs_devices->open_devices);
1425                 if (btrfs_test_opt(tree_root, DEGRADED))
1426                         printk("continuing in degraded mode\n");
1427                 else {
1428                         goto fail_sb_buffer;
1429                 }
1430         }
1431
1432         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
1433
1434         nodesize = btrfs_super_nodesize(disk_super);
1435         leafsize = btrfs_super_leafsize(disk_super);
1436         sectorsize = btrfs_super_sectorsize(disk_super);
1437         stripesize = btrfs_super_stripesize(disk_super);
1438         tree_root->nodesize = nodesize;
1439         tree_root->leafsize = leafsize;
1440         tree_root->sectorsize = sectorsize;
1441         tree_root->stripesize = stripesize;
1442
1443         sb->s_blocksize = sectorsize;
1444         sb->s_blocksize_bits = blksize_bits(sectorsize);
1445
1446         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
1447                     sizeof(disk_super->magic))) {
1448                 printk("btrfs: valid FS not found on %s\n", sb->s_id);
1449                 goto fail_sb_buffer;
1450         }
1451
1452         mutex_lock(&fs_info->chunk_mutex);
1453         ret = btrfs_read_sys_array(tree_root);
1454         mutex_unlock(&fs_info->chunk_mutex);
1455         if (ret) {
1456                 printk("btrfs: failed to read the system array on %s\n",
1457                        sb->s_id);
1458                 goto fail_sys_array;
1459         }
1460
1461         blocksize = btrfs_level_size(tree_root,
1462                                      btrfs_super_chunk_root_level(disk_super));
1463
1464         __setup_root(nodesize, leafsize, sectorsize, stripesize,
1465                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
1466
1467         chunk_root->node = read_tree_block(chunk_root,
1468                                            btrfs_super_chunk_root(disk_super),
1469                                            blocksize, 0);
1470         BUG_ON(!chunk_root->node);
1471
1472         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
1473                  (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
1474                  BTRFS_UUID_SIZE);
1475
1476         mutex_lock(&fs_info->chunk_mutex);
1477         ret = btrfs_read_chunk_tree(chunk_root);
1478         mutex_unlock(&fs_info->chunk_mutex);
1479         BUG_ON(ret);
1480
1481         btrfs_close_extra_devices(fs_devices);
1482
1483         blocksize = btrfs_level_size(tree_root,
1484                                      btrfs_super_root_level(disk_super));
1485
1486
1487         tree_root->node = read_tree_block(tree_root,
1488                                           btrfs_super_root(disk_super),
1489                                           blocksize, 0);
1490         if (!tree_root->node)
1491                 goto fail_sb_buffer;
1492
1493
1494         ret = find_and_setup_root(tree_root, fs_info,
1495                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
1496         if (ret)
1497                 goto fail_tree_root;
1498         extent_root->track_dirty = 1;
1499
1500         ret = find_and_setup_root(tree_root, fs_info,
1501                                   BTRFS_DEV_TREE_OBJECTID, dev_root);
1502         dev_root->track_dirty = 1;
1503
1504         if (ret)
1505                 goto fail_extent_root;
1506
1507         btrfs_read_block_groups(extent_root);
1508
1509         fs_info->generation = btrfs_super_generation(disk_super) + 1;
1510         fs_info->data_alloc_profile = (u64)-1;
1511         fs_info->metadata_alloc_profile = (u64)-1;
1512         fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
1513         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
1514                                                "btrfs-cleaner");
1515         if (!fs_info->cleaner_kthread)
1516                 goto fail_extent_root;
1517
1518         fs_info->transaction_kthread = kthread_run(transaction_kthread,
1519                                                    tree_root,
1520                                                    "btrfs-transaction");
1521         if (!fs_info->transaction_kthread)
1522                 goto fail_cleaner;
1523
1524
1525         return tree_root;
1526
1527 fail_cleaner:
1528         kthread_stop(fs_info->cleaner_kthread);
1529 fail_extent_root:
1530         free_extent_buffer(extent_root->node);
1531 fail_tree_root:
1532         free_extent_buffer(tree_root->node);
1533 fail_sys_array:
1534 fail_sb_buffer:
1535         btrfs_stop_workers(&fs_info->fixup_workers);
1536         btrfs_stop_workers(&fs_info->workers);
1537         btrfs_stop_workers(&fs_info->endio_workers);
1538         btrfs_stop_workers(&fs_info->endio_write_workers);
1539         btrfs_stop_workers(&fs_info->submit_workers);
1540 fail_iput:
1541         iput(fs_info->btree_inode);
1542 fail:
1543         btrfs_close_devices(fs_info->fs_devices);
1544         btrfs_mapping_tree_free(&fs_info->mapping_tree);
1545
1546         kfree(extent_root);
1547         kfree(tree_root);
1548 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1549         bdi_destroy(&fs_info->bdi);
1550 #endif
1551         kfree(fs_info);
1552         return ERR_PTR(err);
1553 }
1554
1555 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
1556 {
1557         char b[BDEVNAME_SIZE];
1558
1559         if (uptodate) {
1560                 set_buffer_uptodate(bh);
1561         } else {
1562                 if (!buffer_eopnotsupp(bh) && printk_ratelimit()) {
1563                         printk(KERN_WARNING "lost page write due to "
1564                                         "I/O error on %s\n",
1565                                        bdevname(bh->b_bdev, b));
1566                 }
1567                 /* note, we dont' set_buffer_write_io_error because we have
1568                  * our own ways of dealing with the IO errors
1569                  */
1570                 clear_buffer_uptodate(bh);
1571         }
1572         unlock_buffer(bh);
1573         put_bh(bh);
1574 }
1575
1576 int write_all_supers(struct btrfs_root *root)
1577 {
1578         struct list_head *cur;
1579         struct list_head *head = &root->fs_info->fs_devices->devices;
1580         struct btrfs_device *dev;
1581         struct btrfs_super_block *sb;
1582         struct btrfs_dev_item *dev_item;
1583         struct buffer_head *bh;
1584         int ret;
1585         int do_barriers;
1586         int max_errors;
1587         int total_errors = 0;
1588         u32 crc;
1589         u64 flags;
1590
1591         max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
1592         do_barriers = !btrfs_test_opt(root, NOBARRIER);
1593
1594         sb = &root->fs_info->super_for_commit;
1595         dev_item = &sb->dev_item;
1596         list_for_each(cur, head) {
1597                 dev = list_entry(cur, struct btrfs_device, dev_list);
1598                 if (!dev->bdev) {
1599                         total_errors++;
1600                         continue;
1601                 }
1602                 if (!dev->in_fs_metadata)
1603                         continue;
1604
1605                 btrfs_set_stack_device_type(dev_item, dev->type);
1606                 btrfs_set_stack_device_id(dev_item, dev->devid);
1607                 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
1608                 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
1609                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
1610                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
1611                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
1612                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
1613                 flags = btrfs_super_flags(sb);
1614                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
1615
1616
1617                 crc = ~(u32)0;
1618                 crc = btrfs_csum_data(root, (char *)sb + BTRFS_CSUM_SIZE, crc,
1619                                       BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
1620                 btrfs_csum_final(crc, sb->csum);
1621
1622                 bh = __getblk(dev->bdev, BTRFS_SUPER_INFO_OFFSET / 4096,
1623                               BTRFS_SUPER_INFO_SIZE);
1624
1625                 memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
1626                 dev->pending_io = bh;
1627
1628                 get_bh(bh);
1629                 set_buffer_uptodate(bh);
1630                 lock_buffer(bh);
1631                 bh->b_end_io = btrfs_end_buffer_write_sync;
1632
1633                 if (do_barriers && dev->barriers) {
1634                         ret = submit_bh(WRITE_BARRIER, bh);
1635                         if (ret == -EOPNOTSUPP) {
1636                                 printk("btrfs: disabling barriers on dev %s\n",
1637                                        dev->name);
1638                                 set_buffer_uptodate(bh);
1639                                 dev->barriers = 0;
1640                                 get_bh(bh);
1641                                 lock_buffer(bh);
1642                                 ret = submit_bh(WRITE, bh);
1643                         }
1644                 } else {
1645                         ret = submit_bh(WRITE, bh);
1646                 }
1647                 if (ret)
1648                         total_errors++;
1649         }
1650         if (total_errors > max_errors) {
1651                 printk("btrfs: %d errors while writing supers\n", total_errors);
1652                 BUG();
1653         }
1654         total_errors = 0;
1655
1656         list_for_each(cur, head) {
1657                 dev = list_entry(cur, struct btrfs_device, dev_list);
1658                 if (!dev->bdev)
1659                         continue;
1660                 if (!dev->in_fs_metadata)
1661                         continue;
1662
1663                 BUG_ON(!dev->pending_io);
1664                 bh = dev->pending_io;
1665                 wait_on_buffer(bh);
1666                 if (!buffer_uptodate(dev->pending_io)) {
1667                         if (do_barriers && dev->barriers) {
1668                                 printk("btrfs: disabling barriers on dev %s\n",
1669                                        dev->name);
1670                                 set_buffer_uptodate(bh);
1671                                 get_bh(bh);
1672                                 lock_buffer(bh);
1673                                 dev->barriers = 0;
1674                                 ret = submit_bh(WRITE, bh);
1675                                 BUG_ON(ret);
1676                                 wait_on_buffer(bh);
1677                                 if (!buffer_uptodate(bh))
1678                                         total_errors++;
1679                         } else {
1680                                 total_errors++;
1681                         }
1682
1683                 }
1684                 dev->pending_io = NULL;
1685                 brelse(bh);
1686         }
1687         if (total_errors > max_errors) {
1688                 printk("btrfs: %d errors while writing supers\n", total_errors);
1689                 BUG();
1690         }
1691         return 0;
1692 }
1693
1694 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
1695                       *root)
1696 {
1697         int ret;
1698
1699         ret = write_all_supers(root);
1700         return ret;
1701 }
1702
1703 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
1704 {
1705         radix_tree_delete(&fs_info->fs_roots_radix,
1706                           (unsigned long)root->root_key.objectid);
1707         if (root->in_sysfs)
1708                 btrfs_sysfs_del_root(root);
1709         if (root->inode)
1710                 iput(root->inode);
1711         if (root->node)
1712                 free_extent_buffer(root->node);
1713         if (root->commit_root)
1714                 free_extent_buffer(root->commit_root);
1715         if (root->name)
1716                 kfree(root->name);
1717         kfree(root);
1718         return 0;
1719 }
1720
1721 static int del_fs_roots(struct btrfs_fs_info *fs_info)
1722 {
1723         int ret;
1724         struct btrfs_root *gang[8];
1725         int i;
1726
1727         while(1) {
1728                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
1729                                              (void **)gang, 0,
1730                                              ARRAY_SIZE(gang));
1731                 if (!ret)
1732                         break;
1733                 for (i = 0; i < ret; i++)
1734                         btrfs_free_fs_root(fs_info, gang[i]);
1735         }
1736         return 0;
1737 }
1738
1739 int close_ctree(struct btrfs_root *root)
1740 {
1741         int ret;
1742         struct btrfs_trans_handle *trans;
1743         struct btrfs_fs_info *fs_info = root->fs_info;
1744
1745         fs_info->closing = 1;
1746         smp_mb();
1747
1748         kthread_stop(root->fs_info->transaction_kthread);
1749         kthread_stop(root->fs_info->cleaner_kthread);
1750
1751         btrfs_clean_old_snapshots(root);
1752         trans = btrfs_start_transaction(root, 1);
1753         ret = btrfs_commit_transaction(trans, root);
1754         /* run commit again to  drop the original snapshot */
1755         trans = btrfs_start_transaction(root, 1);
1756         btrfs_commit_transaction(trans, root);
1757         ret = btrfs_write_and_wait_transaction(NULL, root);
1758         BUG_ON(ret);
1759
1760         write_ctree_super(NULL, root);
1761
1762         if (fs_info->delalloc_bytes) {
1763                 printk("btrfs: at unmount delalloc count %Lu\n",
1764                        fs_info->delalloc_bytes);
1765         }
1766         if (fs_info->total_ref_cache_size) {
1767                 printk("btrfs: at umount reference cache size %Lu\n",
1768                         fs_info->total_ref_cache_size);
1769         }
1770
1771         if (fs_info->extent_root->node)
1772                 free_extent_buffer(fs_info->extent_root->node);
1773
1774         if (fs_info->tree_root->node)
1775                 free_extent_buffer(fs_info->tree_root->node);
1776
1777         if (root->fs_info->chunk_root->node);
1778                 free_extent_buffer(root->fs_info->chunk_root->node);
1779
1780         if (root->fs_info->dev_root->node);
1781                 free_extent_buffer(root->fs_info->dev_root->node);
1782
1783         btrfs_free_block_groups(root->fs_info);
1784         fs_info->closing = 2;
1785         del_fs_roots(fs_info);
1786
1787         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
1788
1789         truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
1790
1791         btrfs_stop_workers(&fs_info->fixup_workers);
1792         btrfs_stop_workers(&fs_info->workers);
1793         btrfs_stop_workers(&fs_info->endio_workers);
1794         btrfs_stop_workers(&fs_info->endio_write_workers);
1795         btrfs_stop_workers(&fs_info->submit_workers);
1796
1797         iput(fs_info->btree_inode);
1798 #if 0
1799         while(!list_empty(&fs_info->hashers)) {
1800                 struct btrfs_hasher *hasher;
1801                 hasher = list_entry(fs_info->hashers.next, struct btrfs_hasher,
1802                                     hashers);
1803                 list_del(&hasher->hashers);
1804                 crypto_free_hash(&fs_info->hash_tfm);
1805                 kfree(hasher);
1806         }
1807 #endif
1808         btrfs_close_devices(fs_info->fs_devices);
1809         btrfs_mapping_tree_free(&fs_info->mapping_tree);
1810
1811 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1812         bdi_destroy(&fs_info->bdi);
1813 #endif
1814
1815         kfree(fs_info->extent_root);
1816         kfree(fs_info->tree_root);
1817         kfree(fs_info->chunk_root);
1818         kfree(fs_info->dev_root);
1819         return 0;
1820 }
1821
1822 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
1823 {
1824         int ret;
1825         struct inode *btree_inode = buf->first_page->mapping->host;
1826
1827         ret = extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf);
1828         if (!ret)
1829                 return ret;
1830
1831         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
1832                                     parent_transid);
1833         return !ret;
1834 }
1835
1836 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
1837 {
1838         struct inode *btree_inode = buf->first_page->mapping->host;
1839         return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
1840                                           buf);
1841 }
1842
1843 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
1844 {
1845         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1846         u64 transid = btrfs_header_generation(buf);
1847         struct inode *btree_inode = root->fs_info->btree_inode;
1848
1849         WARN_ON(!btrfs_tree_locked(buf));
1850         if (transid != root->fs_info->generation) {
1851                 printk(KERN_CRIT "transid mismatch buffer %llu, found %Lu running %Lu\n",
1852                         (unsigned long long)buf->start,
1853                         transid, root->fs_info->generation);
1854                 WARN_ON(1);
1855         }
1856         set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree, buf);
1857 }
1858
1859 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
1860 {
1861         /*
1862          * looks as though older kernels can get into trouble with
1863          * this code, they end up stuck in balance_dirty_pages forever
1864          */
1865         struct extent_io_tree *tree;
1866         u64 num_dirty;
1867         u64 start = 0;
1868         unsigned long thresh = 96 * 1024 * 1024;
1869         tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
1870
1871         if (current_is_pdflush() || current->flags & PF_MEMALLOC)
1872                 return;
1873
1874         num_dirty = count_range_bits(tree, &start, (u64)-1,
1875                                      thresh, EXTENT_DIRTY);
1876         if (num_dirty > thresh) {
1877                 balance_dirty_pages_ratelimited_nr(
1878                                    root->fs_info->btree_inode->i_mapping, 1);
1879         }
1880         return;
1881 }
1882
1883 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
1884 {
1885         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1886         int ret;
1887         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
1888         if (ret == 0) {
1889                 buf->flags |= EXTENT_UPTODATE;
1890         }
1891         return ret;
1892 }
1893
1894 static struct extent_io_ops btree_extent_io_ops = {
1895         .writepage_io_hook = btree_writepage_io_hook,
1896         .readpage_end_io_hook = btree_readpage_end_io_hook,
1897         .submit_bio_hook = btree_submit_bio_hook,
1898         /* note we're sharing with inode.c for the merge bio hook */
1899         .merge_bio_hook = btrfs_merge_bio_hook,
1900 };