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>
  26 #include <linux/workqueue.h>
  27 #include <linux/kthread.h>
  28 #include <linux/freezer.h>
  29 #include <linux/crc32c.h>
  30 #include "compat.h"
  31 #include "ctree.h"
  32 #include "disk-io.h"
  33 #include "transaction.h"
  34 #include "btrfs_inode.h"
  35 #include "volumes.h"
  36 #include "print-tree.h"
  37 #include "async-thread.h"
  38 #include "locking.h"
  39 #include "tree-log.h"
  40 #include "free-space-cache.h"
  41
  42 static struct extent_io_ops btree_extent_io_ops;
  43 static void end_workqueue_fn(struct btrfs_work *work);
  44 static void free_fs_root(struct btrfs_root *root);
  45
  46 static atomic_t btrfs_bdi_num = ATOMIC_INIT(0);
  47
  48 /*
  49  * end_io_wq structs are used to do processing in task context when an IO is
  50  * complete.  This is used during reads to verify checksums, and it is used
  51  * by writes to insert metadata for new file extents after IO is complete.
  52  */
  53 struct end_io_wq {
  54         struct bio *bio;
  55         bio_end_io_t *end_io;
  56         void *private;
  57         struct btrfs_fs_info *info;
  58         int error;
  59         int metadata;
  60         struct list_head list;
  61         struct btrfs_work work;
  62 };
  63
  64 /*
  65  * async submit bios are used to offload expensive checksumming
  66  * onto the worker threads.  They checksum file and metadata bios
  67  * just before they are sent down the IO stack.
  68  */
  69 struct async_submit_bio {
  70         struct inode *inode;
  71         struct bio *bio;
  72         struct list_head list;
  73         extent_submit_bio_hook_t *submit_bio_start;
  74         extent_submit_bio_hook_t *submit_bio_done;
  75         int rw;
  76         int mirror_num;
  77         unsigned long bio_flags;
  78         struct btrfs_work work;
  79 };
  80
  81 /* These are used to set the lockdep class on the extent buffer locks.
  82  * The class is set by the readpage_end_io_hook after the buffer has
  83  * passed csum validation but before the pages are unlocked.
  84  *
  85  * The lockdep class is also set by btrfs_init_new_buffer on freshly
  86  * allocated blocks.
  87  *
  88  * The class is based on the level in the tree block, which allows lockdep
  89  * to know that lower nodes nest inside the locks of higher nodes.
  90  *
  91  * We also add a check to make sure the highest level of the tree is
  92  * the same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this
  93  * code needs update as well.
  94  */
  95 #ifdef CONFIG_DEBUG_LOCK_ALLOC
  96 # if BTRFS_MAX_LEVEL != 8
  97 #  error
  98 # endif
  99 static struct lock_class_key btrfs_eb_class[BTRFS_MAX_LEVEL + 1];
 100 static const char *btrfs_eb_name[BTRFS_MAX_LEVEL + 1] = {
 101         /* leaf */
 102         "btrfs-extent-00",
 103         "btrfs-extent-01",
 104         "btrfs-extent-02",
 105         "btrfs-extent-03",
 106         "btrfs-extent-04",
 107         "btrfs-extent-05",
 108         "btrfs-extent-06",
 109         "btrfs-extent-07",
 110         /* highest possible level */
 111         "btrfs-extent-08",
 112 };
 113 #endif
 114
 115 /*
 116  * extents on the btree inode are pretty simple, there's one extent
 117  * that covers the entire device
 118  */
 119 static struct extent_map *btree_get_extent(struct inode *inode,
 120                 struct page *page, size_t page_offset, u64 start, u64 len,
 121                 int create)
 122 {
 123         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 124         struct extent_map *em;
 125         int ret;
 126
 127         read_lock(&em_tree->lock);
 128         em = lookup_extent_mapping(em_tree, start, len);
 129         if (em) {
 130                 em->bdev =
 131                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 132                 read_unlock(&em_tree->lock);
 133                 goto out;
 134         }
 135         read_unlock(&em_tree->lock);
 136
 137         em = alloc_extent_map(GFP_NOFS);
 138         if (!em) {
 139                 em = ERR_PTR(-ENOMEM);
 140                 goto out;
 141         }
 142         em->start = 0;
 143         em->len = (u64)-1;
 144         em->block_len = (u64)-1;
 145         em->block_start = 0;
 146         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 147
 148         write_lock(&em_tree->lock);
 149         ret = add_extent_mapping(em_tree, em);
 150         if (ret == -EEXIST) {
 151                 u64 failed_start = em->start;
 152                 u64 failed_len = em->len;
 153
 154                 free_extent_map(em);
 155                 em = lookup_extent_mapping(em_tree, start, len);
 156                 if (em) {
 157                         ret = 0;
 158                 } else {
 159                         em = lookup_extent_mapping(em_tree, failed_start,
 160                                                    failed_len);
 161                         ret = -EIO;
 162                 }
 163         } else if (ret) {
 164                 free_extent_map(em);
 165                 em = NULL;
 166         }
 167         write_unlock(&em_tree->lock);
 168
 169         if (ret)
 170                 em = ERR_PTR(ret);
 171 out:
 172         return em;
 173 }
 174
 175 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
 176 {
 177         return crc32c(seed, data, len);
 178 }
 179
 180 void btrfs_csum_final(u32 crc, char *result)
 181 {
 182         *(__le32 *)result = ~cpu_to_le32(crc);
 183 }
 184
 185 /*
 186  * compute the csum for a btree block, and either verify it or write it
 187  * into the csum field of the block.
 188  */
 189 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 190                            int verify)
 191 {
 192         u16 csum_size =
 193                 btrfs_super_csum_size(&root->fs_info->super_copy);
 194         char *result = NULL;
 195         unsigned long len;
 196         unsigned long cur_len;
 197         unsigned long offset = BTRFS_CSUM_SIZE;
 198         char *map_token = NULL;
 199         char *kaddr;
 200         unsigned long map_start;
 201         unsigned long map_len;
 202         int err;
 203         u32 crc = ~(u32)0;
 204         unsigned long inline_result;
 205
 206         len = buf->len - offset;
 207         while (len > 0) {
 208                 err = map_private_extent_buffer(buf, offset, 32,
 209                                         &map_token, &kaddr,
 210                                         &map_start, &map_len, KM_USER0);
 211                 if (err)
 212                         return 1;
 213                 cur_len = min(len, map_len - (offset - map_start));
 214                 crc = btrfs_csum_data(root, kaddr + offset - map_start,
 215                                       crc, cur_len);
 216                 len -= cur_len;
 217                 offset += cur_len;
 218                 unmap_extent_buffer(buf, map_token, KM_USER0);
 219         }
 220         if (csum_size > sizeof(inline_result)) {
 221                 result = kzalloc(csum_size * sizeof(char), GFP_NOFS);
 222                 if (!result)
 223                         return 1;
 224         } else {
 225                 result = (char *)&inline_result;
 226         }
 227
 228         btrfs_csum_final(crc, result);
 229
 230         if (verify) {
 231                 if (memcmp_extent_buffer(buf, result, 0, csum_size)) {
 232                         u32 val;
 233                         u32 found = 0;
 234                         memcpy(&found, result, csum_size);
 235
 236                         read_extent_buffer(buf, &val, 0, csum_size);
 237                         if (printk_ratelimit()) {
 238                                 printk(KERN_INFO "btrfs: %s checksum verify "
 239                                        "failed on %llu wanted %X found %X "
 240                                        "level %d\n",
 241                                        root->fs_info->sb->s_id,
 242                                        (unsigned long long)buf->start, val, found,
 243                                        btrfs_header_level(buf));
 244                         }
 245                         if (result != (char *)&inline_result)
 246                                 kfree(result);
 247                         return 1;
 248                 }
 249         } else {
 250                 write_extent_buffer(buf, result, 0, csum_size);
 251         }
 252         if (result != (char *)&inline_result)
 253                 kfree(result);
 254         return 0;
 255 }
 256
 257 /*
 258  * we can't consider a given block up to date unless the transid of the
 259  * block matches the transid in the parent node's pointer.  This is how we
 260  * detect blocks that either didn't get written at all or got written
 261  * in the wrong place.
 262  */
 263 static int verify_parent_transid(struct extent_io_tree *io_tree,
 264                                  struct extent_buffer *eb, u64 parent_transid)
 265 {
 266         int ret;
 267
 268         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
 269                 return 0;
 270
 271         lock_extent(io_tree, eb->start, eb->start + eb->len - 1, GFP_NOFS);
 272         if (extent_buffer_uptodate(io_tree, eb) &&
 273             btrfs_header_generation(eb) == parent_transid) {
 274                 ret = 0;
 275                 goto out;
 276         }
 277         if (printk_ratelimit()) {
 278                 printk("parent transid verify failed on %llu wanted %llu "
 279                        "found %llu\n",
 280                        (unsigned long long)eb->start,
 281                        (unsigned long long)parent_transid,
 282                        (unsigned long long)btrfs_header_generation(eb));
 283         }
 284         ret = 1;
 285         clear_extent_buffer_uptodate(io_tree, eb);
 286 out:
 287         unlock_extent(io_tree, eb->start, eb->start + eb->len - 1,
 288                       GFP_NOFS);
 289         return ret;
 290 }
 291
 292 /*
 293  * helper to read a given tree block, doing retries as required when
 294  * the checksums don't match and we have alternate mirrors to try.
 295  */
 296 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
 297                                           struct extent_buffer *eb,
 298                                           u64 start, u64 parent_transid)
 299 {
 300         struct extent_io_tree *io_tree;
 301         int ret;
 302         int num_copies = 0;
 303         int mirror_num = 0;
 304
 305         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
 306         while (1) {
 307                 ret = read_extent_buffer_pages(io_tree, eb, start, 1,
 308                                                btree_get_extent, mirror_num);
 309                 if (!ret &&
 310                     !verify_parent_transid(io_tree, eb, parent_transid))
 311                         return ret;
 312
 313                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
 314                                               eb->start, eb->len);
 315                 if (num_copies == 1)
 316                         return ret;
 317
 318                 mirror_num++;
 319                 if (mirror_num > num_copies)
 320                         return ret;
 321         }
 322         return -EIO;
 323 }
 324
 325 /*
 326  * checksum a dirty tree block before IO.  This has extra checks to make sure
 327  * we only fill in the checksum field in the first page of a multi-page block
 328  */
 329
 330 static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 331 {
 332         struct extent_io_tree *tree;
 333         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
 334         u64 found_start;
 335         int found_level;
 336         unsigned long len;
 337         struct extent_buffer *eb;
 338         int ret;
 339
 340         tree = &BTRFS_I(page->mapping->host)->io_tree;
 341
 342         if (page->private == EXTENT_PAGE_PRIVATE)
 343                 goto out;
 344         if (!page->private)
 345                 goto out;
 346         len = page->private >> 2;
 347         WARN_ON(len == 0);
 348
 349         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 350         ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE,
 351                                              btrfs_header_generation(eb));
 352         BUG_ON(ret);
 353         found_start = btrfs_header_bytenr(eb);
 354         if (found_start != start) {
 355                 WARN_ON(1);
 356                 goto err;
 357         }
 358         if (eb->first_page != page) {
 359                 WARN_ON(1);
 360                 goto err;
 361         }
 362         if (!PageUptodate(page)) {
 363                 WARN_ON(1);
 364                 goto err;
 365         }
 366         found_level = btrfs_header_level(eb);
 367
 368         csum_tree_block(root, eb, 0);
 369 err:
 370         free_extent_buffer(eb);
 371 out:
 372         return 0;
 373 }
 374
 375 static int check_tree_block_fsid(struct btrfs_root *root,
 376                                  struct extent_buffer *eb)
 377 {
 378         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
 379         u8 fsid[BTRFS_UUID_SIZE];
 380         int ret = 1;
 381
 382         read_extent_buffer(eb, fsid, (unsigned long)btrfs_header_fsid(eb),
 383                            BTRFS_FSID_SIZE);
 384         while (fs_devices) {
 385                 if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
 386                         ret = 0;
 387                         break;
 388                 }
 389                 fs_devices = fs_devices->seed;
 390         }
 391         return ret;
 392 }
 393
 394 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 395 void btrfs_set_buffer_lockdep_class(struct extent_buffer *eb, int level)
 396 {
 397         lockdep_set_class_and_name(&eb->lock,
 398                            &btrfs_eb_class[level],
 399                            btrfs_eb_name[level]);
 400 }
 401 #endif
 402
 403 static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
 404                                struct extent_state *state)
 405 {
 406         struct extent_io_tree *tree;
 407         u64 found_start;
 408         int found_level;
 409         unsigned long len;
 410         struct extent_buffer *eb;
 411         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 412         int ret = 0;
 413
 414         tree = &BTRFS_I(page->mapping->host)->io_tree;
 415         if (page->private == EXTENT_PAGE_PRIVATE)
 416                 goto out;
 417         if (!page->private)
 418                 goto out;
 419
 420         len = page->private >> 2;
 421         WARN_ON(len == 0);
 422
 423         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 424
 425         found_start = btrfs_header_bytenr(eb);
 426         if (found_start != start) {
 427                 if (printk_ratelimit()) {
 428                         printk(KERN_INFO "btrfs bad tree block start "
 429                                "%llu %llu\n",
 430                                (unsigned long long)found_start,
 431                                (unsigned long long)eb->start);
 432                 }
 433                 ret = -EIO;
 434                 goto err;
 435         }
 436         if (eb->first_page != page) {
 437                 printk(KERN_INFO "btrfs bad first page %lu %lu\n",
 438                        eb->first_page->index, page->index);
 439                 WARN_ON(1);
 440                 ret = -EIO;
 441                 goto err;
 442         }
 443         if (check_tree_block_fsid(root, eb)) {
 444                 if (printk_ratelimit()) {
 445                         printk(KERN_INFO "btrfs bad fsid on block %llu\n",
 446                                (unsigned long long)eb->start);
 447                 }
 448                 ret = -EIO;
 449                 goto err;
 450         }
 451         found_level = btrfs_header_level(eb);
 452
 453         btrfs_set_buffer_lockdep_class(eb, found_level);
 454
 455         ret = csum_tree_block(root, eb, 1);
 456         if (ret)
 457                 ret = -EIO;
 458
 459         end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
 460         end = eb->start + end - 1;
 461 err:
 462         free_extent_buffer(eb);
 463 out:
 464         return ret;
 465 }
 466
 467 static void end_workqueue_bio(struct bio *bio, int err)
 468 {
 469         struct end_io_wq *end_io_wq = bio->bi_private;
 470         struct btrfs_fs_info *fs_info;
 471
 472         fs_info = end_io_wq->info;
 473         end_io_wq->error = err;
 474         end_io_wq->work.func = end_workqueue_fn;
 475         end_io_wq->work.flags = 0;
 476
 477         if (bio->bi_rw & (1 << BIO_RW)) {
 478                 if (end_io_wq->metadata)
 479                         btrfs_queue_worker(&fs_info->endio_meta_write_workers,
 480                                            &end_io_wq->work);
 481                 else
 482                         btrfs_queue_worker(&fs_info->endio_write_workers,
 483                                            &end_io_wq->work);
 484         } else {
 485                 if (end_io_wq->metadata)
 486                         btrfs_queue_worker(&fs_info->endio_meta_workers,
 487                                            &end_io_wq->work);
 488                 else
 489                         btrfs_queue_worker(&fs_info->endio_workers,
 490                                            &end_io_wq->work);
 491         }
 492 }
 493
 494 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 495                         int metadata)
 496 {
 497         struct end_io_wq *end_io_wq;
 498         end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
 499         if (!end_io_wq)
 500                 return -ENOMEM;
 501
 502         end_io_wq->private = bio->bi_private;
 503         end_io_wq->end_io = bio->bi_end_io;
 504         end_io_wq->info = info;
 505         end_io_wq->error = 0;
 506         end_io_wq->bio = bio;
 507         end_io_wq->metadata = metadata;
 508
 509         bio->bi_private = end_io_wq;
 510         bio->bi_end_io = end_workqueue_bio;
 511         return 0;
 512 }
 513
 514 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
 515 {
 516         unsigned long limit = min_t(unsigned long,
 517                                     info->workers.max_workers,
 518                                     info->fs_devices->open_devices);
 519         return 256 * limit;
 520 }
 521
 522 int btrfs_congested_async(struct btrfs_fs_info *info, int iodone)
 523 {
 524         return atomic_read(&info->nr_async_bios) >
 525                 btrfs_async_submit_limit(info);
 526 }
 527
 528 static void run_one_async_start(struct btrfs_work *work)
 529 {
 530         struct btrfs_fs_info *fs_info;
 531         struct async_submit_bio *async;
 532
 533         async = container_of(work, struct  async_submit_bio, work);
 534         fs_info = BTRFS_I(async->inode)->root->fs_info;
 535         async->submit_bio_start(async->inode, async->rw, async->bio,
 536                                async->mirror_num, async->bio_flags);
 537 }
 538
 539 static void run_one_async_done(struct btrfs_work *work)
 540 {
 541         struct btrfs_fs_info *fs_info;
 542         struct async_submit_bio *async;
 543         int limit;
 544
 545         async = container_of(work, struct  async_submit_bio, work);
 546         fs_info = BTRFS_I(async->inode)->root->fs_info;
 547
 548         limit = btrfs_async_submit_limit(fs_info);
 549         limit = limit * 2 / 3;
 550
 551         atomic_dec(&fs_info->nr_async_submits);
 552
 553         if (atomic_read(&fs_info->nr_async_submits) < limit &&
 554             waitqueue_active(&fs_info->async_submit_wait))
 555                 wake_up(&fs_info->async_submit_wait);
 556
 557         async->submit_bio_done(async->inode, async->rw, async->bio,
 558                                async->mirror_num, async->bio_flags);
 559 }
 560
 561 static void run_one_async_free(struct btrfs_work *work)
 562 {
 563         struct async_submit_bio *async;
 564
 565         async = container_of(work, struct  async_submit_bio, work);
 566         kfree(async);
 567 }
 568
 569 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
 570                         int rw, struct bio *bio, int mirror_num,
 571                         unsigned long bio_flags,
 572                         extent_submit_bio_hook_t *submit_bio_start,
 573                         extent_submit_bio_hook_t *submit_bio_done)
 574 {
 575         struct async_submit_bio *async;
 576
 577         async = kmalloc(sizeof(*async), GFP_NOFS);
 578         if (!async)
 579                 return -ENOMEM;
 580
 581         async->inode = inode;
 582         async->rw = rw;
 583         async->bio = bio;
 584         async->mirror_num = mirror_num;
 585         async->submit_bio_start = submit_bio_start;
 586         async->submit_bio_done = submit_bio_done;
 587
 588         async->work.func = run_one_async_start;
 589         async->work.ordered_func = run_one_async_done;
 590         async->work.ordered_free = run_one_async_free;
 591
 592         async->work.flags = 0;
 593         async->bio_flags = bio_flags;
 594
 595         atomic_inc(&fs_info->nr_async_submits);
 596
 597         if (rw & (1 << BIO_RW_SYNCIO))
 598                 btrfs_set_work_high_prio(&async->work);
 599
 600         btrfs_queue_worker(&fs_info->workers, &async->work);
 601
 602         while (atomic_read(&fs_info->async_submit_draining) &&
 603               atomic_read(&fs_info->nr_async_submits)) {
 604                 wait_event(fs_info->async_submit_wait,
 605                            (atomic_read(&fs_info->nr_async_submits) == 0));
 606         }
 607
 608         return 0;
 609 }
 610
 611 static int btree_csum_one_bio(struct bio *bio)
 612 {
 613         struct bio_vec *bvec = bio->bi_io_vec;
 614         int bio_index = 0;
 615         struct btrfs_root *root;
 616
 617         WARN_ON(bio->bi_vcnt <= 0);
 618         while (bio_index < bio->bi_vcnt) {
 619                 root = BTRFS_I(bvec->bv_page->mapping->host)->root;
 620                 csum_dirty_buffer(root, bvec->bv_page);
 621                 bio_index++;
 622                 bvec++;
 623         }
 624         return 0;
 625 }
 626
 627 static int __btree_submit_bio_start(struct inode *inode, int rw,
 628                                     struct bio *bio, int mirror_num,
 629                                     unsigned long bio_flags)
 630 {
 631         /*
 632          * when we're called for a write, we're already in the async
 633          * submission context.  Just jump into btrfs_map_bio
 634          */
 635         btree_csum_one_bio(bio);
 636         return 0;
 637 }
 638
 639 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
 640                                  int mirror_num, unsigned long bio_flags)
 641 {
 642         /*
 643          * when we're called for a write, we're already in the async
 644          * submission context.  Just jump into btrfs_map_bio
 645          */
 646         return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
 647 }
 648
 649 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 650                                  int mirror_num, unsigned long bio_flags)
 651 {
 652         int ret;
 653
 654         ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
 655                                           bio, 1);
 656         BUG_ON(ret);
 657
 658         if (!(rw & (1 << BIO_RW))) {
 659                 /*
 660                  * called for a read, do the setup so that checksum validation
 661                  * can happen in the async kernel threads
 662                  */
 663                 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
 664                                      mirror_num, 0);
 665         }
 666
 667         /*
 668          * kthread helpers are used to submit writes so that checksumming
 669          * can happen in parallel across all CPUs
 670          */
 671         return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
 672                                    inode, rw, bio, mirror_num, 0,
 673                                    __btree_submit_bio_start,
 674                                    __btree_submit_bio_done);
 675 }
 676
 677 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 678 {
 679         struct extent_io_tree *tree;
 680         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 681         struct extent_buffer *eb;
 682         int was_dirty;
 683
 684         tree = &BTRFS_I(page->mapping->host)->io_tree;
 685         if (!(current->flags & PF_MEMALLOC)) {
 686                 return extent_write_full_page(tree, page,
 687                                               btree_get_extent, wbc);
 688         }
 689
 690         redirty_page_for_writepage(wbc, page);
 691         eb = btrfs_find_tree_block(root, page_offset(page),
 692                                       PAGE_CACHE_SIZE);
 693         WARN_ON(!eb);
 694
 695         was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
 696         if (!was_dirty) {
 697                 spin_lock(&root->fs_info->delalloc_lock);
 698                 root->fs_info->dirty_metadata_bytes += PAGE_CACHE_SIZE;
 699                 spin_unlock(&root->fs_info->delalloc_lock);
 700         }
 701         free_extent_buffer(eb);
 702
 703         unlock_page(page);
 704         return 0;
 705 }
 706
 707 static int btree_writepages(struct address_space *mapping,
 708                             struct writeback_control *wbc)
 709 {
 710         struct extent_io_tree *tree;
 711         tree = &BTRFS_I(mapping->host)->io_tree;
 712         if (wbc->sync_mode == WB_SYNC_NONE) {
 713                 struct btrfs_root *root = BTRFS_I(mapping->host)->root;
 714                 u64 num_dirty;
 715                 unsigned long thresh = 32 * 1024 * 1024;
 716
 717                 if (wbc->for_kupdate)
 718                         return 0;
 719
 720                 /* this is a bit racy, but that's ok */
 721                 num_dirty = root->fs_info->dirty_metadata_bytes;
 722                 if (num_dirty < thresh)
 723                         return 0;
 724         }
 725         return extent_writepages(tree, mapping, btree_get_extent, wbc);
 726 }
 727
 728 static int btree_readpage(struct file *file, struct page *page)
 729 {
 730         struct extent_io_tree *tree;
 731         tree = &BTRFS_I(page->mapping->host)->io_tree;
 732         return extent_read_full_page(tree, page, btree_get_extent);
 733 }
 734
 735 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
 736 {
 737         struct extent_io_tree *tree;
 738         struct extent_map_tree *map;
 739         int ret;
 740
 741         if (PageWriteback(page) || PageDirty(page))
 742                 return 0;
 743
 744         tree = &BTRFS_I(page->mapping->host)->io_tree;
 745         map = &BTRFS_I(page->mapping->host)->extent_tree;
 746
 747         ret = try_release_extent_state(map, tree, page, gfp_flags);
 748         if (!ret)
 749                 return 0;
 750
 751         ret = try_release_extent_buffer(tree, page);
 752         if (ret == 1) {
 753                 ClearPagePrivate(page);
 754                 set_page_private(page, 0);
 755                 page_cache_release(page);
 756         }
 757
 758         return ret;
 759 }
 760
 761 static void btree_invalidatepage(struct page *page, unsigned long offset)
 762 {
 763         struct extent_io_tree *tree;
 764         tree = &BTRFS_I(page->mapping->host)->io_tree;
 765         extent_invalidatepage(tree, page, offset);
 766         btree_releasepage(page, GFP_NOFS);
 767         if (PagePrivate(page)) {
 768                 printk(KERN_WARNING "btrfs warning page private not zero "
 769                        "on page %llu\n", (unsigned long long)page_offset(page));
 770                 ClearPagePrivate(page);
 771                 set_page_private(page, 0);
 772                 page_cache_release(page);
 773         }
 774 }
 775
 776 static const struct address_space_operations btree_aops = {
 777         .readpage       = btree_readpage,
 778         .writepage      = btree_writepage,
 779         .writepages     = btree_writepages,
 780         .releasepage    = btree_releasepage,
 781         .invalidatepage = btree_invalidatepage,
 782         .sync_page      = block_sync_page,
 783 };
 784
 785 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
 786                          u64 parent_transid)
 787 {
 788         struct extent_buffer *buf = NULL;
 789         struct inode *btree_inode = root->fs_info->btree_inode;
 790         int ret = 0;
 791
 792         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 793         if (!buf)
 794                 return 0;
 795         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
 796                                  buf, 0, 0, btree_get_extent, 0);
 797         free_extent_buffer(buf);
 798         return ret;
 799 }
 800
 801 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
 802                                             u64 bytenr, u32 blocksize)
 803 {
 804         struct inode *btree_inode = root->fs_info->btree_inode;
 805         struct extent_buffer *eb;
 806         eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 807                                 bytenr, blocksize, GFP_NOFS);
 808         return eb;
 809 }
 810
 811 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 812                                                  u64 bytenr, u32 blocksize)
 813 {
 814         struct inode *btree_inode = root->fs_info->btree_inode;
 815         struct extent_buffer *eb;
 816
 817         eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 818                                  bytenr, blocksize, NULL, GFP_NOFS);
 819         return eb;
 820 }
 821
 822
 823 int btrfs_write_tree_block(struct extent_buffer *buf)
 824 {
 825         return filemap_fdatawrite_range(buf->first_page->mapping, buf->start,
 826                                         buf->start + buf->len - 1);
 827 }
 828
 829 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
 830 {
 831         return filemap_fdatawait_range(buf->first_page->mapping,
 832                                        buf->start, buf->start + buf->len - 1);
 833 }
 834
 835 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 836                                       u32 blocksize, u64 parent_transid)
 837 {
 838         struct extent_buffer *buf = NULL;
 839         struct inode *btree_inode = root->fs_info->btree_inode;
 840         struct extent_io_tree *io_tree;
 841         int ret;
 842
 843         io_tree = &BTRFS_I(btree_inode)->io_tree;
 844
 845         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 846         if (!buf)
 847                 return NULL;
 848
 849         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
 850
 851         if (ret == 0)
 852                 set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
 853         return buf;
 854
 855 }
 856
 857 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 858                      struct extent_buffer *buf)
 859 {
 860         struct inode *btree_inode = root->fs_info->btree_inode;
 861         if (btrfs_header_generation(buf) ==
 862             root->fs_info->running_transaction->transid) {
 863                 btrfs_assert_tree_locked(buf);
 864
 865                 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
 866                         spin_lock(&root->fs_info->delalloc_lock);
 867                         if (root->fs_info->dirty_metadata_bytes >= buf->len)
 868                                 root->fs_info->dirty_metadata_bytes -= buf->len;
 869                         else
 870                                 WARN_ON(1);
 871                         spin_unlock(&root->fs_info->delalloc_lock);
 872                 }
 873
 874                 /* ugh, clear_extent_buffer_dirty needs to lock the page */
 875                 btrfs_set_lock_blocking(buf);
 876                 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
 877                                           buf);
 878         }
 879         return 0;
 880 }
 881
 882 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
 883                         u32 stripesize, struct btrfs_root *root,
 884                         struct btrfs_fs_info *fs_info,
 885                         u64 objectid)
 886 {
 887         root->node = NULL;
 888         root->commit_root = NULL;
 889         root->sectorsize = sectorsize;
 890         root->nodesize = nodesize;
 891         root->leafsize = leafsize;
 892         root->stripesize = stripesize;
 893         root->ref_cows = 0;
 894         root->track_dirty = 0;
 895         root->in_radix = 0;
 896         root->clean_orphans = 0;
 897
 898         root->fs_info = fs_info;
 899         root->objectid = objectid;
 900         root->last_trans = 0;
 901         root->highest_objectid = 0;
 902         root->name = NULL;
 903         root->in_sysfs = 0;
 904         root->inode_tree.rb_node = NULL;
 905
 906         INIT_LIST_HEAD(&root->dirty_list);
 907         INIT_LIST_HEAD(&root->orphan_list);
 908         INIT_LIST_HEAD(&root->root_list);
 909         spin_lock_init(&root->node_lock);
 910         spin_lock_init(&root->list_lock);
 911         spin_lock_init(&root->inode_lock);
 912         mutex_init(&root->objectid_mutex);
 913         mutex_init(&root->log_mutex);
 914         init_waitqueue_head(&root->log_writer_wait);
 915         init_waitqueue_head(&root->log_commit_wait[0]);
 916         init_waitqueue_head(&root->log_commit_wait[1]);
 917         atomic_set(&root->log_commit[0], 0);
 918         atomic_set(&root->log_commit[1], 0);
 919         atomic_set(&root->log_writers, 0);
 920         root->log_batch = 0;
 921         root->log_transid = 0;
 922         root->last_log_commit = 0;
 923         extent_io_tree_init(&root->dirty_log_pages,
 924                              fs_info->btree_inode->i_mapping, GFP_NOFS);
 925
 926         memset(&root->root_key, 0, sizeof(root->root_key));
 927         memset(&root->root_item, 0, sizeof(root->root_item));
 928         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
 929         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
 930         root->defrag_trans_start = fs_info->generation;
 931         init_completion(&root->kobj_unregister);
 932         root->defrag_running = 0;
 933         root->root_key.objectid = objectid;
 934         root->anon_super.s_root = NULL;
 935         root->anon_super.s_dev = 0;
 936         INIT_LIST_HEAD(&root->anon_super.s_list);
 937         INIT_LIST_HEAD(&root->anon_super.s_instances);
 938         init_rwsem(&root->anon_super.s_umount);
 939
 940         return 0;
 941 }
 942
 943 static int find_and_setup_root(struct btrfs_root *tree_root,
 944                                struct btrfs_fs_info *fs_info,
 945                                u64 objectid,
 946                                struct btrfs_root *root)
 947 {
 948         int ret;
 949         u32 blocksize;
 950         u64 generation;
 951
 952         __setup_root(tree_root->nodesize, tree_root->leafsize,
 953                      tree_root->sectorsize, tree_root->stripesize,
 954                      root, fs_info, objectid);
 955         ret = btrfs_find_last_root(tree_root, objectid,
 956                                    &root->root_item, &root->root_key);
 957         if (ret > 0)
 958                 return -ENOENT;
 959         BUG_ON(ret);
 960
 961         generation = btrfs_root_generation(&root->root_item);
 962         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
 963         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
 964                                      blocksize, generation);
 965         BUG_ON(!root->node);
 966         root->commit_root = btrfs_root_node(root);
 967         return 0;
 968 }
 969
 970 int btrfs_free_log_root_tree(struct btrfs_trans_handle *trans,
 971                              struct btrfs_fs_info *fs_info)
 972 {
 973         struct extent_buffer *eb;
 974         struct btrfs_root *log_root_tree = fs_info->log_root_tree;
 975         u64 start = 0;
 976         u64 end = 0;
 977         int ret;
 978
 979         if (!log_root_tree)
 980                 return 0;
 981
 982         while (1) {
 983                 ret = find_first_extent_bit(&log_root_tree->dirty_log_pages,
 984                                 0, &start, &end, EXTENT_DIRTY | EXTENT_NEW);
 985                 if (ret)
 986                         break;
 987
 988                 clear_extent_bits(&log_root_tree->dirty_log_pages, start, end,
 989                                   EXTENT_DIRTY | EXTENT_NEW, GFP_NOFS);
 990         }
 991         eb = fs_info->log_root_tree->node;
 992
 993         WARN_ON(btrfs_header_level(eb) != 0);
 994         WARN_ON(btrfs_header_nritems(eb) != 0);
 995
 996         ret = btrfs_free_reserved_extent(fs_info->tree_root,
 997                                 eb->start, eb->len);
 998         BUG_ON(ret);
 999
1000         free_extent_buffer(eb);
1001         kfree(fs_info->log_root_tree);
1002         fs_info->log_root_tree = NULL;
1003         return 0;
1004 }
1005
1006 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
1007                                          struct btrfs_fs_info *fs_info)
1008 {
1009         struct btrfs_root *root;
1010         struct btrfs_root *tree_root = fs_info->tree_root;
1011         struct extent_buffer *leaf;
1012
1013         root = kzalloc(sizeof(*root), GFP_NOFS);
1014         if (!root)
1015                 return ERR_PTR(-ENOMEM);
1016
1017         __setup_root(tree_root->nodesize, tree_root->leafsize,
1018                      tree_root->sectorsize, tree_root->stripesize,
1019                      root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1020
1021         root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
1022         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1023         root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
1024         /*
1025          * log trees do not get reference counted because they go away
1026          * before a real commit is actually done.  They do store pointers
1027          * to file data extents, and those reference counts still get
1028          * updated (along with back refs to the log tree).
1029          */
1030         root->ref_cows = 0;
1031
1032         leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
1033                                       BTRFS_TREE_LOG_OBJECTID, NULL, 0, 0, 0);
1034         if (IS_ERR(leaf)) {
1035                 kfree(root);
1036                 return ERR_CAST(leaf);
1037         }
1038
1039         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1040         btrfs_set_header_bytenr(leaf, leaf->start);
1041         btrfs_set_header_generation(leaf, trans->transid);
1042         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1043         btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
1044         root->node = leaf;
1045
1046         write_extent_buffer(root->node, root->fs_info->fsid,
1047                             (unsigned long)btrfs_header_fsid(root->node),
1048                             BTRFS_FSID_SIZE);
1049         btrfs_mark_buffer_dirty(root->node);
1050         btrfs_tree_unlock(root->node);
1051         return root;
1052 }
1053
1054 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
1055                              struct btrfs_fs_info *fs_info)
1056 {
1057         struct btrfs_root *log_root;
1058
1059         log_root = alloc_log_tree(trans, fs_info);
1060         if (IS_ERR(log_root))
1061                 return PTR_ERR(log_root);
1062         WARN_ON(fs_info->log_root_tree);
1063         fs_info->log_root_tree = log_root;
1064         return 0;
1065 }
1066
1067 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
1068                        struct btrfs_root *root)
1069 {
1070         struct btrfs_root *log_root;
1071         struct btrfs_inode_item *inode_item;
1072
1073         log_root = alloc_log_tree(trans, root->fs_info);
1074         if (IS_ERR(log_root))
1075                 return PTR_ERR(log_root);
1076
1077         log_root->last_trans = trans->transid;
1078         log_root->root_key.offset = root->root_key.objectid;
1079
1080         inode_item = &log_root->root_item.inode;
1081         inode_item->generation = cpu_to_le64(1);
1082         inode_item->size = cpu_to_le64(3);
1083         inode_item->nlink = cpu_to_le32(1);
1084         inode_item->nbytes = cpu_to_le64(root->leafsize);
1085         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
1086
1087         btrfs_set_root_node(&log_root->root_item, log_root->node);
1088
1089         WARN_ON(root->log_root);
1090         root->log_root = log_root;
1091         root->log_transid = 0;
1092         root->last_log_commit = 0;
1093         return 0;
1094 }
1095
1096 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
1097                                                struct btrfs_key *location)
1098 {
1099         struct btrfs_root *root;
1100         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1101         struct btrfs_path *path;
1102         struct extent_buffer *l;
1103         u64 generation;
1104         u32 blocksize;
1105         int ret = 0;
1106
1107         root = kzalloc(sizeof(*root), GFP_NOFS);
1108         if (!root)
1109                 return ERR_PTR(-ENOMEM);
1110         if (location->offset == (u64)-1) {
1111                 ret = find_and_setup_root(tree_root, fs_info,
1112                                           location->objectid, root);
1113                 if (ret) {
1114                         kfree(root);
1115                         return ERR_PTR(ret);
1116                 }
1117                 goto out;
1118         }
1119
1120         __setup_root(tree_root->nodesize, tree_root->leafsize,
1121                      tree_root->sectorsize, tree_root->stripesize,
1122                      root, fs_info, location->objectid);
1123
1124         path = btrfs_alloc_path();
1125         BUG_ON(!path);
1126         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
1127         if (ret == 0) {
1128                 l = path->nodes[0];
1129                 read_extent_buffer(l, &root->root_item,
1130                                 btrfs_item_ptr_offset(l, path->slots[0]),
1131                                 sizeof(root->root_item));
1132                 memcpy(&root->root_key, location, sizeof(*location));
1133         }
1134         btrfs_free_path(path);
1135         if (ret) {
1136                 if (ret > 0)
1137                         ret = -ENOENT;
1138                 return ERR_PTR(ret);
1139         }
1140
1141         generation = btrfs_root_generation(&root->root_item);
1142         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1143         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1144                                      blocksize, generation);
1145         root->commit_root = btrfs_root_node(root);
1146         BUG_ON(!root->node);
1147 out:
1148         if (location->objectid != BTRFS_TREE_LOG_OBJECTID)
1149                 root->ref_cows = 1;
1150
1151         return root;
1152 }
1153
1154 struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
1155                                         u64 root_objectid)
1156 {
1157         struct btrfs_root *root;
1158
1159         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID)
1160                 return fs_info->tree_root;
1161         if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID)
1162                 return fs_info->extent_root;
1163
1164         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1165                                  (unsigned long)root_objectid);
1166         return root;
1167 }
1168
1169 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
1170                                               struct btrfs_key *location)
1171 {
1172         struct btrfs_root *root;
1173         int ret;
1174
1175         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1176                 return fs_info->tree_root;
1177         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1178                 return fs_info->extent_root;
1179         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1180                 return fs_info->chunk_root;
1181         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1182                 return fs_info->dev_root;
1183         if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
1184                 return fs_info->csum_root;
1185 again:
1186         spin_lock(&fs_info->fs_roots_radix_lock);
1187         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1188                                  (unsigned long)location->objectid);
1189         spin_unlock(&fs_info->fs_roots_radix_lock);
1190         if (root)
1191                 return root;
1192
1193         ret = btrfs_find_orphan_item(fs_info->tree_root, location->objectid);
1194         if (ret == 0)
1195                 ret = -ENOENT;
1196         if (ret < 0)
1197                 return ERR_PTR(ret);
1198
1199         root = btrfs_read_fs_root_no_radix(fs_info->tree_root, location);
1200         if (IS_ERR(root))
1201                 return root;
1202
1203         WARN_ON(btrfs_root_refs(&root->root_item) == 0);
1204         set_anon_super(&root->anon_super, NULL);
1205
1206         ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
1207         if (ret)
1208                 goto fail;
1209
1210         spin_lock(&fs_info->fs_roots_radix_lock);
1211         ret = radix_tree_insert(&fs_info->fs_roots_radix,
1212                                 (unsigned long)root->root_key.objectid,
1213                                 root);
1214         if (ret == 0) {
1215                 root->in_radix = 1;
1216                 root->clean_orphans = 1;
1217         }
1218         spin_unlock(&fs_info->fs_roots_radix_lock);
1219         radix_tree_preload_end();
1220         if (ret) {
1221                 if (ret == -EEXIST) {
1222                         free_fs_root(root);
1223                         goto again;
1224                 }
1225                 goto fail;
1226         }
1227
1228         ret = btrfs_find_dead_roots(fs_info->tree_root,
1229                                     root->root_key.objectid);
1230         WARN_ON(ret);
1231         return root;
1232 fail:
1233         free_fs_root(root);
1234         return ERR_PTR(ret);
1235 }
1236
1237 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
1238                                       struct btrfs_key *location,
1239                                       const char *name, int namelen)
1240 {
1241         return btrfs_read_fs_root_no_name(fs_info, location);
1242 #if 0
1243         struct btrfs_root *root;
1244         int ret;
1245
1246         root = btrfs_read_fs_root_no_name(fs_info, location);
1247         if (!root)
1248                 return NULL;
1249
1250         if (root->in_sysfs)
1251                 return root;
1252
1253         ret = btrfs_set_root_name(root, name, namelen);
1254         if (ret) {
1255                 free_extent_buffer(root->node);
1256                 kfree(root);
1257                 return ERR_PTR(ret);
1258         }
1259
1260         ret = btrfs_sysfs_add_root(root);
1261         if (ret) {
1262                 free_extent_buffer(root->node);
1263                 kfree(root->name);
1264                 kfree(root);
1265                 return ERR_PTR(ret);
1266         }
1267         root->in_sysfs = 1;
1268         return root;
1269 #endif
1270 }
1271
1272 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1273 {
1274         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1275         int ret = 0;
1276         struct btrfs_device *device;
1277         struct backing_dev_info *bdi;
1278
1279         list_for_each_entry(device, &info->fs_devices->devices, dev_list) {
1280                 if (!device->bdev)
1281                         continue;
1282                 bdi = blk_get_backing_dev_info(device->bdev);
1283                 if (bdi && bdi_congested(bdi, bdi_bits)) {
1284                         ret = 1;
1285                         break;
1286                 }
1287         }
1288         return ret;
1289 }
1290
1291 /*
1292  * this unplugs every device on the box, and it is only used when page
1293  * is null
1294  */
1295 static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1296 {
1297         struct btrfs_device *device;
1298         struct btrfs_fs_info *info;
1299
1300         info = (struct btrfs_fs_info *)bdi->unplug_io_data;
1301         list_for_each_entry(device, &info->fs_devices->devices, dev_list) {
1302                 if (!device->bdev)
1303                         continue;
1304
1305                 bdi = blk_get_backing_dev_info(device->bdev);
1306                 if (bdi->unplug_io_fn)
1307                         bdi->unplug_io_fn(bdi, page);
1308         }
1309 }
1310
1311 static void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1312 {
1313         struct inode *inode;
1314         struct extent_map_tree *em_tree;
1315         struct extent_map *em;
1316         struct address_space *mapping;
1317         u64 offset;
1318
1319         /* the generic O_DIRECT read code does this */
1320         if (1 || !page) {
1321                 __unplug_io_fn(bdi, page);
1322                 return;
1323         }
1324
1325         /*
1326          * page->mapping may change at any time.  Get a consistent copy
1327          * and use that for everything below
1328          */
1329         smp_mb();
1330         mapping = page->mapping;
1331         if (!mapping)
1332                 return;
1333
1334         inode = mapping->host;
1335
1336         /*
1337          * don't do the expensive searching for a small number of
1338          * devices
1339          */
1340         if (BTRFS_I(inode)->root->fs_info->fs_devices->open_devices <= 2) {
1341                 __unplug_io_fn(bdi, page);
1342                 return;
1343         }
1344
1345         offset = page_offset(page);
1346
1347         em_tree = &BTRFS_I(inode)->extent_tree;
1348         read_lock(&em_tree->lock);
1349         em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
1350         read_unlock(&em_tree->lock);
1351         if (!em) {
1352                 __unplug_io_fn(bdi, page);
1353                 return;
1354         }
1355
1356         if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1357                 free_extent_map(em);
1358                 __unplug_io_fn(bdi, page);
1359                 return;
1360         }
1361         offset = offset - em->start;
1362         btrfs_unplug_page(&BTRFS_I(inode)->root->fs_info->mapping_tree,
1363                           em->block_start + offset, page);
1364         free_extent_map(em);
1365 }
1366
1367 /*
1368  * If this fails, caller must call bdi_destroy() to get rid of the
1369  * bdi again.
1370  */
1371 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1372 {
1373         int err;
1374
1375         bdi->name = "btrfs";
1376         bdi->capabilities = BDI_CAP_MAP_COPY;
1377         err = bdi_init(bdi);
1378         if (err)
1379                 return err;
1380
1381         err = bdi_register(bdi, NULL, "btrfs-%d",
1382                                 atomic_inc_return(&btrfs_bdi_num));
1383         if (err) {
1384                 bdi_destroy(bdi);
1385                 return err;
1386         }
1387
1388         bdi->ra_pages   = default_backing_dev_info.ra_pages;
1389         bdi->unplug_io_fn       = btrfs_unplug_io_fn;
1390         bdi->unplug_io_data     = info;
1391         bdi->congested_fn       = btrfs_congested_fn;
1392         bdi->congested_data     = info;
1393         return 0;
1394 }
1395
1396 static int bio_ready_for_csum(struct bio *bio)
1397 {
1398         u64 length = 0;
1399         u64 buf_len = 0;
1400         u64 start = 0;
1401         struct page *page;
1402         struct extent_io_tree *io_tree = NULL;
1403         struct btrfs_fs_info *info = NULL;
1404         struct bio_vec *bvec;
1405         int i;
1406         int ret;
1407
1408         bio_for_each_segment(bvec, bio, i) {
1409                 page = bvec->bv_page;
1410                 if (page->private == EXTENT_PAGE_PRIVATE) {
1411                         length += bvec->bv_len;
1412                         continue;
1413                 }
1414                 if (!page->private) {
1415                         length += bvec->bv_len;
1416                         continue;
1417                 }
1418                 length = bvec->bv_len;
1419                 buf_len = page->private >> 2;
1420                 start = page_offset(page) + bvec->bv_offset;
1421                 io_tree = &BTRFS_I(page->mapping->host)->io_tree;
1422                 info = BTRFS_I(page->mapping->host)->root->fs_info;
1423         }
1424         /* are we fully contained in this bio? */
1425         if (buf_len <= length)
1426                 return 1;
1427
1428         ret = extent_range_uptodate(io_tree, start + length,
1429                                     start + buf_len - 1);
1430         return ret;
1431 }
1432
1433 /*
1434  * called by the kthread helper functions to finally call the bio end_io
1435  * functions.  This is where read checksum verification actually happens
1436  */
1437 static void end_workqueue_fn(struct btrfs_work *work)
1438 {
1439         struct bio *bio;
1440         struct end_io_wq *end_io_wq;
1441         struct btrfs_fs_info *fs_info;
1442         int error;
1443
1444         end_io_wq = container_of(work, struct end_io_wq, work);
1445         bio = end_io_wq->bio;
1446         fs_info = end_io_wq->info;
1447
1448         /* metadata bio reads are special because the whole tree block must
1449          * be checksummed at once.  This makes sure the entire block is in
1450          * ram and up to date before trying to verify things.  For
1451          * blocksize <= pagesize, it is basically a noop
1452          */
1453         if (!(bio->bi_rw & (1 << BIO_RW)) && end_io_wq->metadata &&
1454             !bio_ready_for_csum(bio)) {
1455                 btrfs_queue_worker(&fs_info->endio_meta_workers,
1456                                    &end_io_wq->work);
1457                 return;
1458         }
1459         error = end_io_wq->error;
1460         bio->bi_private = end_io_wq->private;
1461         bio->bi_end_io = end_io_wq->end_io;
1462         kfree(end_io_wq);
1463         bio_endio(bio, error);
1464 }
1465
1466 static int cleaner_kthread(void *arg)
1467 {
1468         struct btrfs_root *root = arg;
1469
1470         do {
1471                 smp_mb();
1472                 if (root->fs_info->closing)
1473                         break;
1474
1475                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1476
1477                 if (!(root->fs_info->sb->s_flags & MS_RDONLY) &&
1478                     mutex_trylock(&root->fs_info->cleaner_mutex)) {
1479                         btrfs_run_delayed_iputs(root);
1480                         btrfs_clean_old_snapshots(root);
1481                         mutex_unlock(&root->fs_info->cleaner_mutex);
1482                 }
1483
1484                 if (freezing(current)) {
1485                         refrigerator();
1486                 } else {
1487                         smp_mb();
1488                         if (root->fs_info->closing)
1489                                 break;
1490                         set_current_state(TASK_INTERRUPTIBLE);
1491                         schedule();
1492                         __set_current_state(TASK_RUNNING);
1493                 }
1494         } while (!kthread_should_stop());
1495         return 0;
1496 }
1497
1498 static int transaction_kthread(void *arg)
1499 {
1500         struct btrfs_root *root = arg;
1501         struct btrfs_trans_handle *trans;
1502         struct btrfs_transaction *cur;
1503         unsigned long now;
1504         unsigned long delay;
1505         int ret;
1506
1507         do {
1508                 smp_mb();
1509                 if (root->fs_info->closing)
1510                         break;
1511
1512                 delay = HZ * 30;
1513                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1514                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1515
1516                 mutex_lock(&root->fs_info->trans_mutex);
1517                 cur = root->fs_info->running_transaction;
1518                 if (!cur) {
1519                         mutex_unlock(&root->fs_info->trans_mutex);
1520                         goto sleep;
1521                 }
1522
1523                 now = get_seconds();
1524                 if (now < cur->start_time || now - cur->start_time < 30) {
1525                         mutex_unlock(&root->fs_info->trans_mutex);
1526                         delay = HZ * 5;
1527                         goto sleep;
1528                 }
1529                 mutex_unlock(&root->fs_info->trans_mutex);
1530                 trans = btrfs_start_transaction(root, 1);
1531                 ret = btrfs_commit_transaction(trans, root);
1532
1533 sleep:
1534                 wake_up_process(root->fs_info->cleaner_kthread);
1535                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1536
1537                 if (freezing(current)) {
1538                         refrigerator();
1539                 } else {
1540                         if (root->fs_info->closing)
1541                                 break;
1542                         set_current_state(TASK_INTERRUPTIBLE);
1543                         schedule_timeout(delay);
1544                         __set_current_state(TASK_RUNNING);
1545                 }
1546         } while (!kthread_should_stop());
1547         return 0;
1548 }
1549
1550 struct btrfs_root *open_ctree(struct super_block *sb,
1551                               struct btrfs_fs_devices *fs_devices,
1552                               char *options)
1553 {
1554         u32 sectorsize;
1555         u32 nodesize;
1556         u32 leafsize;
1557         u32 blocksize;
1558         u32 stripesize;
1559         u64 generation;
1560         u64 features;
1561         struct btrfs_key location;
1562         struct buffer_head *bh;
1563         struct btrfs_root *extent_root = kzalloc(sizeof(struct btrfs_root),
1564                                                  GFP_NOFS);
1565         struct btrfs_root *csum_root = kzalloc(sizeof(struct btrfs_root),
1566                                                  GFP_NOFS);
1567         struct btrfs_root *tree_root = kzalloc(sizeof(struct btrfs_root),
1568                                                GFP_NOFS);
1569         struct btrfs_fs_info *fs_info = kzalloc(sizeof(*fs_info),
1570                                                 GFP_NOFS);
1571         struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root),
1572                                                 GFP_NOFS);
1573         struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root),
1574                                               GFP_NOFS);
1575         struct btrfs_root *log_tree_root;
1576
1577         int ret;
1578         int err = -EINVAL;
1579
1580         struct btrfs_super_block *disk_super;
1581
1582         if (!extent_root || !tree_root || !fs_info ||
1583             !chunk_root || !dev_root || !csum_root) {
1584                 err = -ENOMEM;
1585                 goto fail;
1586         }
1587
1588         ret = init_srcu_struct(&fs_info->subvol_srcu);
1589         if (ret) {
1590                 err = ret;
1591                 goto fail;
1592         }
1593
1594         ret = setup_bdi(fs_info, &fs_info->bdi);
1595         if (ret) {
1596                 err = ret;
1597                 goto fail_srcu;
1598         }
1599
1600         fs_info->btree_inode = new_inode(sb);
1601         if (!fs_info->btree_inode) {
1602                 err = -ENOMEM;
1603                 goto fail_bdi;
1604         }
1605
1606         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
1607         INIT_LIST_HEAD(&fs_info->trans_list);
1608         INIT_LIST_HEAD(&fs_info->dead_roots);
1609         INIT_LIST_HEAD(&fs_info->delayed_iputs);
1610         INIT_LIST_HEAD(&fs_info->hashers);
1611         INIT_LIST_HEAD(&fs_info->delalloc_inodes);
1612         INIT_LIST_HEAD(&fs_info->ordered_operations);
1613         INIT_LIST_HEAD(&fs_info->caching_block_groups);
1614         spin_lock_init(&fs_info->delalloc_lock);
1615         spin_lock_init(&fs_info->new_trans_lock);
1616         spin_lock_init(&fs_info->ref_cache_lock);
1617         spin_lock_init(&fs_info->fs_roots_radix_lock);
1618         spin_lock_init(&fs_info->delayed_iput_lock);
1619
1620         init_completion(&fs_info->kobj_unregister);
1621         fs_info->tree_root = tree_root;
1622         fs_info->extent_root = extent_root;
1623         fs_info->csum_root = csum_root;
1624         fs_info->chunk_root = chunk_root;
1625         fs_info->dev_root = dev_root;
1626         fs_info->fs_devices = fs_devices;
1627         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
1628         INIT_LIST_HEAD(&fs_info->space_info);
1629         btrfs_mapping_init(&fs_info->mapping_tree);
1630         atomic_set(&fs_info->nr_async_submits, 0);
1631         atomic_set(&fs_info->async_delalloc_pages, 0);
1632         atomic_set(&fs_info->async_submit_draining, 0);
1633         atomic_set(&fs_info->nr_async_bios, 0);
1634         fs_info->sb = sb;
1635         fs_info->max_extent = (u64)-1;
1636         fs_info->max_inline = 8192 * 1024;
1637         fs_info->metadata_ratio = 0;
1638
1639         fs_info->thread_pool_size = min_t(unsigned long,
1640                                           num_online_cpus() + 2, 8);
1641
1642         INIT_LIST_HEAD(&fs_info->ordered_extents);
1643         spin_lock_init(&fs_info->ordered_extent_lock);
1644
1645         sb->s_blocksize = 4096;
1646         sb->s_blocksize_bits = blksize_bits(4096);
1647         sb->s_bdi = &fs_info->bdi;
1648
1649         fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
1650         fs_info->btree_inode->i_nlink = 1;
1651         /*
1652          * we set the i_size on the btree inode to the max possible int.
1653          * the real end of the address space is determined by all of
1654          * the devices in the system
1655          */
1656         fs_info->btree_inode->i_size = OFFSET_MAX;
1657         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
1658         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
1659
1660         RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
1661         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
1662                              fs_info->btree_inode->i_mapping,
1663                              GFP_NOFS);
1664         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree,
1665                              GFP_NOFS);
1666
1667         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
1668
1669         BTRFS_I(fs_info->btree_inode)->root = tree_root;
1670         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
1671                sizeof(struct btrfs_key));
1672         BTRFS_I(fs_info->btree_inode)->dummy_inode = 1;
1673         insert_inode_hash(fs_info->btree_inode);
1674
1675         spin_lock_init(&fs_info->block_group_cache_lock);
1676         fs_info->block_group_cache_tree.rb_node = NULL;
1677
1678         extent_io_tree_init(&fs_info->freed_extents[0],
1679                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1680         extent_io_tree_init(&fs_info->freed_extents[1],
1681                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1682         fs_info->pinned_extents = &fs_info->freed_extents[0];
1683         fs_info->do_barriers = 1;
1684
1685
1686         mutex_init(&fs_info->trans_mutex);
1687         mutex_init(&fs_info->ordered_operations_mutex);
1688         mutex_init(&fs_info->tree_log_mutex);
1689         mutex_init(&fs_info->chunk_mutex);
1690         mutex_init(&fs_info->transaction_kthread_mutex);
1691         mutex_init(&fs_info->cleaner_mutex);
1692         mutex_init(&fs_info->volume_mutex);
1693         init_rwsem(&fs_info->extent_commit_sem);
1694         init_rwsem(&fs_info->cleanup_work_sem);
1695         init_rwsem(&fs_info->subvol_sem);
1696
1697         btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
1698         btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
1699
1700         init_waitqueue_head(&fs_info->transaction_throttle);
1701         init_waitqueue_head(&fs_info->transaction_wait);
1702         init_waitqueue_head(&fs_info->async_submit_wait);
1703
1704         __setup_root(4096, 4096, 4096, 4096, tree_root,
1705                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
1706
1707
1708         bh = btrfs_read_dev_super(fs_devices->latest_bdev);
1709         if (!bh)
1710                 goto fail_iput;
1711
1712         memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));
1713         memcpy(&fs_info->super_for_commit, &fs_info->super_copy,
1714                sizeof(fs_info->super_for_commit));
1715         brelse(bh);
1716
1717         memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
1718
1719         disk_super = &fs_info->super_copy;
1720         if (!btrfs_super_root(disk_super))
1721                 goto fail_iput;
1722
1723         ret = btrfs_parse_options(tree_root, options);
1724         if (ret) {
1725                 err = ret;
1726                 goto fail_iput;
1727         }
1728
1729         features = btrfs_super_incompat_flags(disk_super) &
1730                 ~BTRFS_FEATURE_INCOMPAT_SUPP;
1731         if (features) {
1732                 printk(KERN_ERR "BTRFS: couldn't mount because of "
1733                        "unsupported optional features (%Lx).\n",
1734                        (unsigned long long)features);
1735                 err = -EINVAL;
1736                 goto fail_iput;
1737         }
1738
1739         features = btrfs_super_incompat_flags(disk_super);
1740         if (!(features & BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF)) {
1741                 features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
1742                 btrfs_set_super_incompat_flags(disk_super, features);
1743         }
1744
1745         features = btrfs_super_compat_ro_flags(disk_super) &
1746                 ~BTRFS_FEATURE_COMPAT_RO_SUPP;
1747         if (!(sb->s_flags & MS_RDONLY) && features) {
1748                 printk(KERN_ERR "BTRFS: couldn't mount RDWR because of "
1749                        "unsupported option features (%Lx).\n",
1750                        (unsigned long long)features);
1751                 err = -EINVAL;
1752                 goto fail_iput;
1753         }
1754
1755         btrfs_init_workers(&fs_info->generic_worker,
1756                            "genwork", 1, NULL);
1757
1758         btrfs_init_workers(&fs_info->workers, "worker",
1759                            fs_info->thread_pool_size,
1760                            &fs_info->generic_worker);
1761
1762         btrfs_init_workers(&fs_info->delalloc_workers, "delalloc",
1763                            fs_info->thread_pool_size,
1764                            &fs_info->generic_worker);
1765
1766         btrfs_init_workers(&fs_info->submit_workers, "submit",
1767                            min_t(u64, fs_devices->num_devices,
1768                            fs_info->thread_pool_size),
1769                            &fs_info->generic_worker);
1770         btrfs_init_workers(&fs_info->enospc_workers, "enospc",
1771                            fs_info->thread_pool_size,
1772                            &fs_info->generic_worker);
1773
1774         /* a higher idle thresh on the submit workers makes it much more
1775          * likely that bios will be send down in a sane order to the
1776          * devices
1777          */
1778         fs_info->submit_workers.idle_thresh = 64;
1779
1780         fs_info->workers.idle_thresh = 16;
1781         fs_info->workers.ordered = 1;
1782
1783         fs_info->delalloc_workers.idle_thresh = 2;
1784         fs_info->delalloc_workers.ordered = 1;
1785
1786         btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1,
1787                            &fs_info->generic_worker);
1788         btrfs_init_workers(&fs_info->endio_workers, "endio",
1789                            fs_info->thread_pool_size,
1790                            &fs_info->generic_worker);
1791         btrfs_init_workers(&fs_info->endio_meta_workers, "endio-meta",
1792                            fs_info->thread_pool_size,
1793                            &fs_info->generic_worker);
1794         btrfs_init_workers(&fs_info->endio_meta_write_workers,
1795                            "endio-meta-write", fs_info->thread_pool_size,
1796                            &fs_info->generic_worker);
1797         btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
1798                            fs_info->thread_pool_size,
1799                            &fs_info->generic_worker);
1800
1801         /*
1802          * endios are largely parallel and should have a very
1803          * low idle thresh
1804          */
1805         fs_info->endio_workers.idle_thresh = 4;
1806         fs_info->endio_meta_workers.idle_thresh = 4;
1807
1808         fs_info->endio_write_workers.idle_thresh = 2;
1809         fs_info->endio_meta_write_workers.idle_thresh = 2;
1810
1811         btrfs_start_workers(&fs_info->workers, 1);
1812         btrfs_start_workers(&fs_info->generic_worker, 1);
1813         btrfs_start_workers(&fs_info->submit_workers, 1);
1814         btrfs_start_workers(&fs_info->delalloc_workers, 1);
1815         btrfs_start_workers(&fs_info->fixup_workers, 1);
1816         btrfs_start_workers(&fs_info->endio_workers, 1);
1817         btrfs_start_workers(&fs_info->endio_meta_workers, 1);
1818         btrfs_start_workers(&fs_info->endio_meta_write_workers, 1);
1819         btrfs_start_workers(&fs_info->endio_write_workers, 1);
1820         btrfs_start_workers(&fs_info->enospc_workers, 1);
1821
1822         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
1823         fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
1824                                     4 * 1024 * 1024 / PAGE_CACHE_SIZE);
1825
1826         nodesize = btrfs_super_nodesize(disk_super);
1827         leafsize = btrfs_super_leafsize(disk_super);
1828         sectorsize = btrfs_super_sectorsize(disk_super);
1829         stripesize = btrfs_super_stripesize(disk_super);
1830         tree_root->nodesize = nodesize;
1831         tree_root->leafsize = leafsize;
1832         tree_root->sectorsize = sectorsize;
1833         tree_root->stripesize = stripesize;
1834
1835         sb->s_blocksize = sectorsize;
1836         sb->s_blocksize_bits = blksize_bits(sectorsize);
1837
1838         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
1839                     sizeof(disk_super->magic))) {
1840                 printk(KERN_INFO "btrfs: valid FS not found on %s\n", sb->s_id);
1841                 goto fail_sb_buffer;
1842         }
1843
1844         mutex_lock(&fs_info->chunk_mutex);
1845         ret = btrfs_read_sys_array(tree_root);
1846         mutex_unlock(&fs_info->chunk_mutex);
1847         if (ret) {
1848                 printk(KERN_WARNING "btrfs: failed to read the system "
1849                        "array on %s\n", sb->s_id);
1850                 goto fail_sb_buffer;
1851         }
1852
1853         blocksize = btrfs_level_size(tree_root,
1854                                      btrfs_super_chunk_root_level(disk_super));
1855         generation = btrfs_super_chunk_root_generation(disk_super);
1856
1857         __setup_root(nodesize, leafsize, sectorsize, stripesize,
1858                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
1859
1860         chunk_root->node = read_tree_block(chunk_root,
1861                                            btrfs_super_chunk_root(disk_super),
1862                                            blocksize, generation);
1863         BUG_ON(!chunk_root->node);
1864         if (!test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
1865                 printk(KERN_WARNING "btrfs: failed to read chunk root on %s\n",
1866                        sb->s_id);
1867                 goto fail_chunk_root;
1868         }
1869         btrfs_set_root_node(&chunk_root->root_item, chunk_root->node);
1870         chunk_root->commit_root = btrfs_root_node(chunk_root);
1871
1872         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
1873            (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
1874            BTRFS_UUID_SIZE);
1875
1876         mutex_lock(&fs_info->chunk_mutex);
1877         ret = btrfs_read_chunk_tree(chunk_root);
1878         mutex_unlock(&fs_info->chunk_mutex);
1879         if (ret) {
1880                 printk(KERN_WARNING "btrfs: failed to read chunk tree on %s\n",
1881                        sb->s_id);
1882                 goto fail_chunk_root;
1883         }
1884
1885         btrfs_close_extra_devices(fs_devices);
1886
1887         blocksize = btrfs_level_size(tree_root,
1888                                      btrfs_super_root_level(disk_super));
1889         generation = btrfs_super_generation(disk_super);
1890
1891         tree_root->node = read_tree_block(tree_root,
1892                                           btrfs_super_root(disk_super),
1893                                           blocksize, generation);
1894         if (!tree_root->node)
1895                 goto fail_chunk_root;
1896         if (!test_bit(EXTENT_BUFFER_UPTODATE, &tree_root->node->bflags)) {
1897                 printk(KERN_WARNING "btrfs: failed to read tree root on %s\n",
1898                        sb->s_id);
1899                 goto fail_tree_root;
1900         }
1901         btrfs_set_root_node(&tree_root->root_item, tree_root->node);
1902         tree_root->commit_root = btrfs_root_node(tree_root);
1903
1904         ret = find_and_setup_root(tree_root, fs_info,
1905                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
1906         if (ret)
1907                 goto fail_tree_root;
1908         extent_root->track_dirty = 1;
1909
1910         ret = find_and_setup_root(tree_root, fs_info,
1911                                   BTRFS_DEV_TREE_OBJECTID, dev_root);
1912         if (ret)
1913                 goto fail_extent_root;
1914         dev_root->track_dirty = 1;
1915
1916         ret = find_and_setup_root(tree_root, fs_info,
1917                                   BTRFS_CSUM_TREE_OBJECTID, csum_root);
1918         if (ret)
1919                 goto fail_dev_root;
1920
1921         csum_root->track_dirty = 1;
1922
1923         btrfs_read_block_groups(extent_root);
1924
1925         fs_info->generation = generation;
1926         fs_info->last_trans_committed = generation;
1927         fs_info->data_alloc_profile = (u64)-1;
1928         fs_info->metadata_alloc_profile = (u64)-1;
1929         fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
1930         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
1931                                                "btrfs-cleaner");
1932         if (IS_ERR(fs_info->cleaner_kthread))
1933                 goto fail_csum_root;
1934
1935         fs_info->transaction_kthread = kthread_run(transaction_kthread,
1936                                                    tree_root,
1937                                                    "btrfs-transaction");
1938         if (IS_ERR(fs_info->transaction_kthread))
1939                 goto fail_cleaner;
1940
1941         if (!btrfs_test_opt(tree_root, SSD) &&
1942             !btrfs_test_opt(tree_root, NOSSD) &&
1943             !fs_info->fs_devices->rotating) {
1944                 printk(KERN_INFO "Btrfs detected SSD devices, enabling SSD "
1945                        "mode\n");
1946                 btrfs_set_opt(fs_info->mount_opt, SSD);
1947         }
1948
1949         if (btrfs_super_log_root(disk_super) != 0) {
1950                 u64 bytenr = btrfs_super_log_root(disk_super);
1951
1952                 if (fs_devices->rw_devices == 0) {
1953                         printk(KERN_WARNING "Btrfs log replay required "
1954                                "on RO media\n");
1955                         err = -EIO;
1956                         goto fail_trans_kthread;
1957                 }
1958                 blocksize =
1959                      btrfs_level_size(tree_root,
1960                                       btrfs_super_log_root_level(disk_super));
1961
1962                 log_tree_root = kzalloc(sizeof(struct btrfs_root),
1963                                                       GFP_NOFS);
1964
1965                 __setup_root(nodesize, leafsize, sectorsize, stripesize,
1966                              log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1967
1968                 log_tree_root->node = read_tree_block(tree_root, bytenr,
1969                                                       blocksize,
1970                                                       generation + 1);
1971                 ret = btrfs_recover_log_trees(log_tree_root);
1972                 BUG_ON(ret);
1973
1974                 if (sb->s_flags & MS_RDONLY) {
1975                         ret =  btrfs_commit_super(tree_root);
1976                         BUG_ON(ret);
1977                 }
1978         }
1979
1980         ret = btrfs_find_orphan_roots(tree_root);
1981         BUG_ON(ret);
1982
1983         if (!(sb->s_flags & MS_RDONLY)) {
1984                 ret = btrfs_recover_relocation(tree_root);
1985                 BUG_ON(ret);
1986         }
1987
1988         location.objectid = BTRFS_FS_TREE_OBJECTID;
1989         location.type = BTRFS_ROOT_ITEM_KEY;
1990         location.offset = (u64)-1;
1991
1992         fs_info->fs_root = btrfs_read_fs_root_no_name(fs_info, &location);
1993         if (!fs_info->fs_root)
1994                 goto fail_trans_kthread;
1995
1996         return tree_root;
1997
1998 fail_trans_kthread:
1999         kthread_stop(fs_info->transaction_kthread);
2000 fail_cleaner:
2001         kthread_stop(fs_info->cleaner_kthread);
2002
2003         /*
2004          * make sure we're done with the btree inode before we stop our
2005          * kthreads
2006          */
2007         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
2008         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2009
2010 fail_csum_root:
2011         free_extent_buffer(csum_root->node);
2012         free_extent_buffer(csum_root->commit_root);
2013 fail_dev_root:
2014         free_extent_buffer(dev_root->node);
2015         free_extent_buffer(dev_root->commit_root);
2016 fail_extent_root:
2017         free_extent_buffer(extent_root->node);
2018         free_extent_buffer(extent_root->commit_root);
2019 fail_tree_root:
2020         free_extent_buffer(tree_root->node);
2021         free_extent_buffer(tree_root->commit_root);
2022 fail_chunk_root:
2023         free_extent_buffer(chunk_root->node);
2024         free_extent_buffer(chunk_root->commit_root);
2025 fail_sb_buffer:
2026         btrfs_stop_workers(&fs_info->generic_worker);
2027         btrfs_stop_workers(&fs_info->fixup_workers);
2028         btrfs_stop_workers(&fs_info->delalloc_workers);
2029         btrfs_stop_workers(&fs_info->workers);
2030         btrfs_stop_workers(&fs_info->endio_workers);
2031         btrfs_stop_workers(&fs_info->endio_meta_workers);
2032         btrfs_stop_workers(&fs_info->endio_meta_write_workers);
2033         btrfs_stop_workers(&fs_info->endio_write_workers);
2034         btrfs_stop_workers(&fs_info->submit_workers);
2035         btrfs_stop_workers(&fs_info->enospc_workers);
2036 fail_iput:
2037         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2038         iput(fs_info->btree_inode);
2039
2040         btrfs_close_devices(fs_info->fs_devices);
2041         btrfs_mapping_tree_free(&fs_info->mapping_tree);
2042 fail_bdi:
2043         bdi_destroy(&fs_info->bdi);
2044 fail_srcu:
2045         cleanup_srcu_struct(&fs_info->subvol_srcu);
2046 fail:
2047         kfree(extent_root);
2048         kfree(tree_root);
2049         kfree(fs_info);
2050         kfree(chunk_root);
2051         kfree(dev_root);
2052         kfree(csum_root);
2053         return ERR_PTR(err);
2054 }
2055
2056 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
2057 {
2058         char b[BDEVNAME_SIZE];
2059
2060         if (uptodate) {
2061                 set_buffer_uptodate(bh);
2062         } else {
2063                 if (!buffer_eopnotsupp(bh) && printk_ratelimit()) {
2064                         printk(KERN_WARNING "lost page write due to "
2065                                         "I/O error on %s\n",
2066                                        bdevname(bh->b_bdev, b));
2067                 }
2068                 /* note, we dont' set_buffer_write_io_error because we have
2069                  * our own ways of dealing with the IO errors
2070                  */
2071                 clear_buffer_uptodate(bh);
2072         }
2073         unlock_buffer(bh);
2074         put_bh(bh);
2075 }
2076
2077 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
2078 {
2079         struct buffer_head *bh;
2080         struct buffer_head *latest = NULL;
2081         struct btrfs_super_block *super;
2082         int i;
2083         u64 transid = 0;
2084         u64 bytenr;
2085
2086         /* we would like to check all the supers, but that would make
2087          * a btrfs mount succeed after a mkfs from a different FS.
2088          * So, we need to add a special mount option to scan for
2089          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
2090          */
2091         for (i = 0; i < 1; i++) {
2092                 bytenr = btrfs_sb_offset(i);
2093                 if (bytenr + 4096 >= i_size_read(bdev->bd_inode))
2094                         break;
2095                 bh = __bread(bdev, bytenr / 4096, 4096);
2096                 if (!bh)
2097                         continue;
2098
2099                 super = (struct btrfs_super_block *)bh->b_data;
2100                 if (btrfs_super_bytenr(super) != bytenr ||
2101                     strncmp((char *)(&super->magic), BTRFS_MAGIC,
2102                             sizeof(super->magic))) {
2103                         brelse(bh);
2104                         continue;
2105                 }
2106
2107                 if (!latest || btrfs_super_generation(super) > transid) {
2108                         brelse(latest);
2109                         latest = bh;
2110                         transid = btrfs_super_generation(super);
2111                 } else {
2112                         brelse(bh);
2113                 }
2114         }
2115         return latest;
2116 }
2117
2118 /*
2119  * this should be called twice, once with wait == 0 and
2120  * once with wait == 1.  When wait == 0 is done, all the buffer heads
2121  * we write are pinned.
2122  *
2123  * They are released when wait == 1 is done.
2124  * max_mirrors must be the same for both runs, and it indicates how
2125  * many supers on this one device should be written.
2126  *
2127  * max_mirrors == 0 means to write them all.
2128  */
2129 static int write_dev_supers(struct btrfs_device *device,
2130                             struct btrfs_super_block *sb,
2131                             int do_barriers, int wait, int max_mirrors)
2132 {
2133         struct buffer_head *bh;
2134         int i;
2135         int ret;
2136         int errors = 0;
2137         u32 crc;
2138         u64 bytenr;
2139         int last_barrier = 0;
2140
2141         if (max_mirrors == 0)
2142                 max_mirrors = BTRFS_SUPER_MIRROR_MAX;
2143
2144         /* make sure only the last submit_bh does a barrier */
2145         if (do_barriers) {
2146                 for (i = 0; i < max_mirrors; i++) {
2147                         bytenr = btrfs_sb_offset(i);
2148                         if (bytenr + BTRFS_SUPER_INFO_SIZE >=
2149                             device->total_bytes)
2150                                 break;
2151                         last_barrier = i;
2152                 }
2153         }
2154
2155         for (i = 0; i < max_mirrors; i++) {
2156                 bytenr = btrfs_sb_offset(i);
2157                 if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
2158                         break;
2159
2160                 if (wait) {
2161                         bh = __find_get_block(device->bdev, bytenr / 4096,
2162                                               BTRFS_SUPER_INFO_SIZE);
2163                         BUG_ON(!bh);
2164                         wait_on_buffer(bh);
2165                         if (!buffer_uptodate(bh))
2166                                 errors++;
2167
2168                         /* drop our reference */
2169                         brelse(bh);
2170
2171                         /* drop the reference from the wait == 0 run */
2172                         brelse(bh);
2173                         continue;
2174                 } else {
2175                         btrfs_set_super_bytenr(sb, bytenr);
2176
2177                         crc = ~(u32)0;
2178                         crc = btrfs_csum_data(NULL, (char *)sb +
2179                                               BTRFS_CSUM_SIZE, crc,
2180                                               BTRFS_SUPER_INFO_SIZE -
2181                                               BTRFS_CSUM_SIZE);
2182                         btrfs_csum_final(crc, sb->csum);
2183
2184                         /*
2185                          * one reference for us, and we leave it for the
2186                          * caller
2187                          */
2188                         bh = __getblk(device->bdev, bytenr / 4096,
2189                                       BTRFS_SUPER_INFO_SIZE);
2190                         memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
2191
2192                         /* one reference for submit_bh */
2193                         get_bh(bh);
2194
2195                         set_buffer_uptodate(bh);
2196                         lock_buffer(bh);
2197                         bh->b_end_io = btrfs_end_buffer_write_sync;
2198                 }
2199
2200                 if (i == last_barrier && do_barriers && device->barriers) {
2201                         ret = submit_bh(WRITE_BARRIER, bh);
2202                         if (ret == -EOPNOTSUPP) {
2203                                 printk("btrfs: disabling barriers on dev %s\n",
2204                                        device->name);
2205                                 set_buffer_uptodate(bh);
2206                                 device->barriers = 0;
2207                                 /* one reference for submit_bh */
2208                                 get_bh(bh);
2209                                 lock_buffer(bh);
2210                                 ret = submit_bh(WRITE_SYNC, bh);
2211                         }
2212                 } else {
2213                         ret = submit_bh(WRITE_SYNC, bh);
2214                 }
2215
2216                 if (ret)
2217                         errors++;
2218         }
2219         return errors < i ? 0 : -1;
2220 }
2221
2222 int write_all_supers(struct btrfs_root *root, int max_mirrors)
2223 {
2224         struct list_head *head;
2225         struct btrfs_device *dev;
2226         struct btrfs_super_block *sb;
2227         struct btrfs_dev_item *dev_item;
2228         int ret;
2229         int do_barriers;
2230         int max_errors;
2231         int total_errors = 0;
2232         u64 flags;
2233
2234         max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
2235         do_barriers = !btrfs_test_opt(root, NOBARRIER);
2236
2237         sb = &root->fs_info->super_for_commit;
2238         dev_item = &sb->dev_item;
2239
2240         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2241         head = &root->fs_info->fs_devices->devices;
2242         list_for_each_entry(dev, head, dev_list) {
2243                 if (!dev->bdev) {
2244                         total_errors++;
2245                         continue;
2246                 }
2247                 if (!dev->in_fs_metadata || !dev->writeable)
2248                         continue;
2249
2250                 btrfs_set_stack_device_generation(dev_item, 0);
2251                 btrfs_set_stack_device_type(dev_item, dev->type);
2252                 btrfs_set_stack_device_id(dev_item, dev->devid);
2253                 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
2254                 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
2255                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
2256                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
2257                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
2258                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
2259                 memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
2260
2261                 flags = btrfs_super_flags(sb);
2262                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
2263
2264                 ret = write_dev_supers(dev, sb, do_barriers, 0, max_mirrors);
2265                 if (ret)
2266                         total_errors++;
2267         }
2268         if (total_errors > max_errors) {
2269                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2270                        total_errors);
2271                 BUG();
2272         }
2273
2274         total_errors = 0;
2275         list_for_each_entry(dev, head, dev_list) {
2276                 if (!dev->bdev)
2277                         continue;
2278                 if (!dev->in_fs_metadata || !dev->writeable)
2279                         continue;
2280
2281                 ret = write_dev_supers(dev, sb, do_barriers, 1, max_mirrors);
2282                 if (ret)
2283                         total_errors++;
2284         }
2285         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2286         if (total_errors > max_errors) {
2287                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2288                        total_errors);
2289                 BUG();
2290         }
2291         return 0;
2292 }
2293
2294 int write_ctree_super(struct btrfs_trans_handle *trans,
2295                       struct btrfs_root *root, int max_mirrors)
2296 {
2297         int ret;
2298
2299         ret = write_all_supers(root, max_mirrors);
2300         return ret;
2301 }
2302
2303 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2304 {
2305         spin_lock(&fs_info->fs_roots_radix_lock);
2306         radix_tree_delete(&fs_info->fs_roots_radix,
2307                           (unsigned long)root->root_key.objectid);
2308         spin_unlock(&fs_info->fs_roots_radix_lock);
2309
2310         if (btrfs_root_refs(&root->root_item) == 0)
2311                 synchronize_srcu(&fs_info->subvol_srcu);
2312
2313         free_fs_root(root);
2314         return 0;
2315 }
2316
2317 static void free_fs_root(struct btrfs_root *root)
2318 {
2319         WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
2320         if (root->anon_super.s_dev) {
2321                 down_write(&root->anon_super.s_umount);
2322                 kill_anon_super(&root->anon_super);
2323         }
2324         free_extent_buffer(root->node);
2325         free_extent_buffer(root->commit_root);
2326         kfree(root->name);
2327         kfree(root);
2328 }
2329
2330 static int del_fs_roots(struct btrfs_fs_info *fs_info)
2331 {
2332         int ret;
2333         struct btrfs_root *gang[8];
2334         int i;
2335
2336         while (!list_empty(&fs_info->dead_roots)) {
2337                 gang[0] = list_entry(fs_info->dead_roots.next,
2338                                      struct btrfs_root, root_list);
2339                 list_del(&gang[0]->root_list);
2340
2341                 if (gang[0]->in_radix) {
2342                         btrfs_free_fs_root(fs_info, gang[0]);
2343                 } else {
2344                         free_extent_buffer(gang[0]->node);
2345                         free_extent_buffer(gang[0]->commit_root);
2346                         kfree(gang[0]);
2347                 }
2348         }
2349
2350         while (1) {
2351                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2352                                              (void **)gang, 0,
2353                                              ARRAY_SIZE(gang));
2354                 if (!ret)
2355                         break;
2356                 for (i = 0; i < ret; i++)
2357                         btrfs_free_fs_root(fs_info, gang[i]);
2358         }
2359         return 0;
2360 }
2361
2362 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
2363 {
2364         u64 root_objectid = 0;
2365         struct btrfs_root *gang[8];
2366         int i;
2367         int ret;
2368
2369         while (1) {
2370                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2371                                              (void **)gang, root_objectid,
2372                                              ARRAY_SIZE(gang));
2373                 if (!ret)
2374                         break;
2375
2376                 root_objectid = gang[ret - 1]->root_key.objectid + 1;
2377                 for (i = 0; i < ret; i++) {
2378                         root_objectid = gang[i]->root_key.objectid;
2379                         btrfs_orphan_cleanup(gang[i]);
2380                 }
2381                 root_objectid++;
2382         }
2383         return 0;
2384 }
2385
2386 int btrfs_commit_super(struct btrfs_root *root)
2387 {
2388         struct btrfs_trans_handle *trans;
2389         int ret;
2390
2391         mutex_lock(&root->fs_info->cleaner_mutex);
2392         btrfs_run_delayed_iputs(root);
2393         btrfs_clean_old_snapshots(root);
2394         mutex_unlock(&root->fs_info->cleaner_mutex);
2395
2396         /* wait until ongoing cleanup work done */
2397         down_write(&root->fs_info->cleanup_work_sem);
2398         up_write(&root->fs_info->cleanup_work_sem);
2399
2400         trans = btrfs_start_transaction(root, 1);
2401         ret = btrfs_commit_transaction(trans, root);
2402         BUG_ON(ret);
2403         /* run commit again to drop the original snapshot */
2404         trans = btrfs_start_transaction(root, 1);
2405         btrfs_commit_transaction(trans, root);
2406         ret = btrfs_write_and_wait_transaction(NULL, root);
2407         BUG_ON(ret);
2408
2409         ret = write_ctree_super(NULL, root, 0);
2410         return ret;
2411 }
2412
2413 int close_ctree(struct btrfs_root *root)
2414 {
2415         struct btrfs_fs_info *fs_info = root->fs_info;
2416         int ret;
2417
2418         fs_info->closing = 1;
2419         smp_mb();
2420
2421         kthread_stop(root->fs_info->transaction_kthread);
2422         kthread_stop(root->fs_info->cleaner_kthread);
2423
2424         if (!(fs_info->sb->s_flags & MS_RDONLY)) {
2425                 ret =  btrfs_commit_super(root);
2426                 if (ret)
2427                         printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
2428         }
2429
2430         fs_info->closing = 2;
2431         smp_mb();
2432
2433         if (fs_info->delalloc_bytes) {
2434                 printk(KERN_INFO "btrfs: at unmount delalloc count %llu\n",
2435                        (unsigned long long)fs_info->delalloc_bytes);
2436         }
2437         if (fs_info->total_ref_cache_size) {
2438                 printk(KERN_INFO "btrfs: at umount reference cache size %llu\n",
2439                        (unsigned long long)fs_info->total_ref_cache_size);
2440         }
2441
2442         free_extent_buffer(fs_info->extent_root->node);
2443         free_extent_buffer(fs_info->extent_root->commit_root);
2444         free_extent_buffer(fs_info->tree_root->node);
2445         free_extent_buffer(fs_info->tree_root->commit_root);
2446         free_extent_buffer(root->fs_info->chunk_root->node);
2447         free_extent_buffer(root->fs_info->chunk_root->commit_root);
2448         free_extent_buffer(root->fs_info->dev_root->node);
2449         free_extent_buffer(root->fs_info->dev_root->commit_root);
2450         free_extent_buffer(root->fs_info->csum_root->node);
2451         free_extent_buffer(root->fs_info->csum_root->commit_root);
2452
2453         btrfs_free_block_groups(root->fs_info);
2454
2455         del_fs_roots(fs_info);
2456
2457         iput(fs_info->btree_inode);
2458
2459         btrfs_stop_workers(&fs_info->generic_worker);
2460         btrfs_stop_workers(&fs_info->fixup_workers);
2461         btrfs_stop_workers(&fs_info->delalloc_workers);
2462         btrfs_stop_workers(&fs_info->workers);
2463         btrfs_stop_workers(&fs_info->endio_workers);
2464         btrfs_stop_workers(&fs_info->endio_meta_workers);
2465         btrfs_stop_workers(&fs_info->endio_meta_write_workers);
2466         btrfs_stop_workers(&fs_info->endio_write_workers);
2467         btrfs_stop_workers(&fs_info->submit_workers);
2468         btrfs_stop_workers(&fs_info->enospc_workers);
2469
2470         btrfs_close_devices(fs_info->fs_devices);
2471         btrfs_mapping_tree_free(&fs_info->mapping_tree);
2472
2473         bdi_destroy(&fs_info->bdi);
2474         cleanup_srcu_struct(&fs_info->subvol_srcu);
2475
2476         kfree(fs_info->extent_root);
2477         kfree(fs_info->tree_root);
2478         kfree(fs_info->chunk_root);
2479         kfree(fs_info->dev_root);
2480         kfree(fs_info->csum_root);
2481         return 0;
2482 }
2483
2484 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
2485 {
2486         int ret;
2487         struct inode *btree_inode = buf->first_page->mapping->host;
2488
2489         ret = extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf);
2490         if (!ret)
2491                 return ret;
2492
2493         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
2494                                     parent_transid);
2495         return !ret;
2496 }
2497
2498 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
2499 {
2500         struct inode *btree_inode = buf->first_page->mapping->host;
2501         return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
2502                                           buf);
2503 }
2504
2505 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
2506 {
2507         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2508         u64 transid = btrfs_header_generation(buf);
2509         struct inode *btree_inode = root->fs_info->btree_inode;
2510         int was_dirty;
2511
2512         btrfs_assert_tree_locked(buf);
2513         if (transid != root->fs_info->generation) {
2514                 printk(KERN_CRIT "btrfs transid mismatch buffer %llu, "
2515                        "found %llu running %llu\n",
2516                         (unsigned long long)buf->start,
2517                         (unsigned long long)transid,
2518                         (unsigned long long)root->fs_info->generation);
2519                 WARN_ON(1);
2520         }
2521         was_dirty = set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
2522                                             buf);
2523         if (!was_dirty) {
2524                 spin_lock(&root->fs_info->delalloc_lock);
2525                 root->fs_info->dirty_metadata_bytes += buf->len;
2526                 spin_unlock(&root->fs_info->delalloc_lock);
2527         }
2528 }
2529
2530 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
2531 {
2532         /*
2533          * looks as though older kernels can get into trouble with
2534          * this code, they end up stuck in balance_dirty_pages forever
2535          */
2536         u64 num_dirty;
2537         unsigned long thresh = 32 * 1024 * 1024;
2538
2539         if (current->flags & PF_MEMALLOC)
2540                 return;
2541
2542         num_dirty = root->fs_info->dirty_metadata_bytes;
2543
2544         if (num_dirty > thresh) {
2545                 balance_dirty_pages_ratelimited_nr(
2546                                    root->fs_info->btree_inode->i_mapping, 1);
2547         }
2548         return;
2549 }
2550
2551 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
2552 {
2553         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2554         int ret;
2555         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
2556         if (ret == 0)
2557                 set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
2558         return ret;
2559 }
2560
2561 int btree_lock_page_hook(struct page *page)
2562 {
2563         struct inode *inode = page->mapping->host;
2564         struct btrfs_root *root = BTRFS_I(inode)->root;
2565         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2566         struct extent_buffer *eb;
2567         unsigned long len;
2568         u64 bytenr = page_offset(page);
2569
2570         if (page->private == EXTENT_PAGE_PRIVATE)
2571                 goto out;
2572
2573         len = page->private >> 2;
2574         eb = find_extent_buffer(io_tree, bytenr, len, GFP_NOFS);
2575         if (!eb)
2576                 goto out;
2577
2578         btrfs_tree_lock(eb);
2579         btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
2580
2581         if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
2582                 spin_lock(&root->fs_info->delalloc_lock);
2583                 if (root->fs_info->dirty_metadata_bytes >= eb->len)
2584                         root->fs_info->dirty_metadata_bytes -= eb->len;
2585                 else
2586                         WARN_ON(1);
2587                 spin_unlock(&root->fs_info->delalloc_lock);
2588         }
2589
2590         btrfs_tree_unlock(eb);
2591         free_extent_buffer(eb);
2592 out:
2593         lock_page(page);
2594         return 0;
2595 }
2596
2597 static struct extent_io_ops btree_extent_io_ops = {
2598         .write_cache_pages_lock_hook = btree_lock_page_hook,
2599         .readpage_end_io_hook = btree_readpage_end_io_hook,
2600         .submit_bio_hook = btree_submit_bio_hook,
2601         /* note we're sharing with inode.c for the merge bio hook */
2602         .merge_bio_hook = btrfs_merge_bio_hook,
2603 };