SAFE public projects git trees. - safe/jmp/linux-2.6/blob - fs/btrfs/disk-io.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/version.h>
  20 #include <linux/fs.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/scatterlist.h>
  23 #include <linux/swap.h>
  24 #include <linux/radix-tree.h>
  25 #include <linux/writeback.h>
  26 #include <linux/buffer_head.h> // for block_sync_page
  27 #include <linux/workqueue.h>
  28 #include <linux/kthread.h>
  29 # include <linux/freezer.h>
  30 #include "crc32c.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 "ref-cache.h"
  40 #include "tree-log.h"
  41
  42 #if 0
  43 static int check_tree_block(struct btrfs_root *root, struct extent_buffer *buf)
  44 {
  45         if (extent_buffer_blocknr(buf) != btrfs_header_blocknr(buf)) {
  46                 printk(KERN_CRIT "buf blocknr(buf) is %llu, header is %llu\n",
  47                        (unsigned long long)extent_buffer_blocknr(buf),
  48                        (unsigned long long)btrfs_header_blocknr(buf));
  49                 return 1;
  50         }
  51         return 0;
  52 }
  53 #endif
  54
  55 static struct extent_io_ops btree_extent_io_ops;
  56 static void end_workqueue_fn(struct btrfs_work *work);
  57
  58 /*
  59  * end_io_wq structs are used to do processing in task context when an IO is
  60  * complete.  This is used during reads to verify checksums, and it is used
  61  * by writes to insert metadata for new file extents after IO is complete.
  62  */
  63 struct end_io_wq {
  64         struct bio *bio;
  65         bio_end_io_t *end_io;
  66         void *private;
  67         struct btrfs_fs_info *info;
  68         int error;
  69         int metadata;
  70         struct list_head list;
  71         struct btrfs_work work;
  72 };
  73
  74 /*
  75  * async submit bios are used to offload expensive checksumming
  76  * onto the worker threads.  They checksum file and metadata bios
  77  * just before they are sent down the IO stack.
  78  */
  79 struct async_submit_bio {
  80         struct inode *inode;
  81         struct bio *bio;
  82         struct list_head list;
  83         extent_submit_bio_hook_t *submit_bio_start;
  84         extent_submit_bio_hook_t *submit_bio_done;
  85         int rw;
  86         int mirror_num;
  87         unsigned long bio_flags;
  88         struct btrfs_work work;
  89 };
  90
  91 /*
  92  * extents on the btree inode are pretty simple, there's one extent
  93  * that covers the entire device
  94  */
  95 struct extent_map *btree_get_extent(struct inode *inode, struct page *page,
  96                                     size_t page_offset, u64 start, u64 len,
  97                                     int create)
  98 {
  99         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 100         struct extent_map *em;
 101         int ret;
 102
 103         spin_lock(&em_tree->lock);
 104         em = lookup_extent_mapping(em_tree, start, len);
 105         if (em) {
 106                 em->bdev =
 107                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 108                 spin_unlock(&em_tree->lock);
 109                 goto out;
 110         }
 111         spin_unlock(&em_tree->lock);
 112
 113         em = alloc_extent_map(GFP_NOFS);
 114         if (!em) {
 115                 em = ERR_PTR(-ENOMEM);
 116                 goto out;
 117         }
 118         em->start = 0;
 119         em->len = (u64)-1;
 120         em->block_len = (u64)-1;
 121         em->block_start = 0;
 122         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 123
 124         spin_lock(&em_tree->lock);
 125         ret = add_extent_mapping(em_tree, em);
 126         if (ret == -EEXIST) {
 127                 u64 failed_start = em->start;
 128                 u64 failed_len = em->len;
 129
 130                 printk("failed to insert %Lu %Lu -> %Lu into tree\n",
 131                        em->start, em->len, em->block_start);
 132                 free_extent_map(em);
 133                 em = lookup_extent_mapping(em_tree, start, len);
 134                 if (em) {
 135                         printk("after failing, found %Lu %Lu %Lu\n",
 136                                em->start, em->len, em->block_start);
 137                         ret = 0;
 138                 } else {
 139                         em = lookup_extent_mapping(em_tree, failed_start,
 140                                                    failed_len);
 141                         if (em) {
 142                                 printk("double failure lookup gives us "
 143                                        "%Lu %Lu -> %Lu\n", em->start,
 144                                        em->len, em->block_start);
 145                                 free_extent_map(em);
 146                         }
 147                         ret = -EIO;
 148                 }
 149         } else if (ret) {
 150                 free_extent_map(em);
 151                 em = NULL;
 152         }
 153         spin_unlock(&em_tree->lock);
 154
 155         if (ret)
 156                 em = ERR_PTR(ret);
 157 out:
 158         return em;
 159 }
 160
 161 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
 162 {
 163         return btrfs_crc32c(seed, data, len);
 164 }
 165
 166 void btrfs_csum_final(u32 crc, char *result)
 167 {
 168         *(__le32 *)result = ~cpu_to_le32(crc);
 169 }
 170
 171 /*
 172  * compute the csum for a btree block, and either verify it or write it
 173  * into the csum field of the block.
 174  */
 175 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 176                            int verify)
 177 {
 178         char result[BTRFS_CRC32_SIZE];
 179         unsigned long len;
 180         unsigned long cur_len;
 181         unsigned long offset = BTRFS_CSUM_SIZE;
 182         char *map_token = NULL;
 183         char *kaddr;
 184         unsigned long map_start;
 185         unsigned long map_len;
 186         int err;
 187         u32 crc = ~(u32)0;
 188
 189         len = buf->len - offset;
 190         while(len > 0) {
 191                 err = map_private_extent_buffer(buf, offset, 32,
 192                                         &map_token, &kaddr,
 193                                         &map_start, &map_len, KM_USER0);
 194                 if (err) {
 195                         printk("failed to map extent buffer! %lu\n",
 196                                offset);
 197                         return 1;
 198                 }
 199                 cur_len = min(len, map_len - (offset - map_start));
 200                 crc = btrfs_csum_data(root, kaddr + offset - map_start,
 201                                       crc, cur_len);
 202                 len -= cur_len;
 203                 offset += cur_len;
 204                 unmap_extent_buffer(buf, map_token, KM_USER0);
 205         }
 206         btrfs_csum_final(crc, result);
 207
 208         if (verify) {
 209                 /* FIXME, this is not good */
 210                 if (memcmp_extent_buffer(buf, result, 0, BTRFS_CRC32_SIZE)) {
 211                         u32 val;
 212                         u32 found = 0;
 213                         memcpy(&found, result, BTRFS_CRC32_SIZE);
 214
 215                         read_extent_buffer(buf, &val, 0, BTRFS_CRC32_SIZE);
 216                         printk("btrfs: %s checksum verify failed on %llu "
 217                                "wanted %X found %X level %d\n",
 218                                root->fs_info->sb->s_id,
 219                                buf->start, val, found, btrfs_header_level(buf));
 220                         return 1;
 221                 }
 222         } else {
 223                 write_extent_buffer(buf, result, 0, BTRFS_CRC32_SIZE);
 224         }
 225         return 0;
 226 }
 227
 228 /*
 229  * we can't consider a given block up to date unless the transid of the
 230  * block matches the transid in the parent node's pointer.  This is how we
 231  * detect blocks that either didn't get written at all or got written
 232  * in the wrong place.
 233  */
 234 static int verify_parent_transid(struct extent_io_tree *io_tree,
 235                                  struct extent_buffer *eb, u64 parent_transid)
 236 {
 237         int ret;
 238
 239         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
 240                 return 0;
 241
 242         lock_extent(io_tree, eb->start, eb->start + eb->len - 1, GFP_NOFS);
 243         if (extent_buffer_uptodate(io_tree, eb) &&
 244             btrfs_header_generation(eb) == parent_transid) {
 245                 ret = 0;
 246                 goto out;
 247         }
 248         printk("parent transid verify failed on %llu wanted %llu found %llu\n",
 249                (unsigned long long)eb->start,
 250                (unsigned long long)parent_transid,
 251                (unsigned long long)btrfs_header_generation(eb));
 252         ret = 1;
 253         clear_extent_buffer_uptodate(io_tree, eb);
 254 out:
 255         unlock_extent(io_tree, eb->start, eb->start + eb->len - 1,
 256                       GFP_NOFS);
 257         return ret;
 258 }
 259
 260 /*
 261  * helper to read a given tree block, doing retries as required when
 262  * the checksums don't match and we have alternate mirrors to try.
 263  */
 264 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
 265                                           struct extent_buffer *eb,
 266                                           u64 start, u64 parent_transid)
 267 {
 268         struct extent_io_tree *io_tree;
 269         int ret;
 270         int num_copies = 0;
 271         int mirror_num = 0;
 272
 273         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
 274         while (1) {
 275                 ret = read_extent_buffer_pages(io_tree, eb, start, 1,
 276                                                btree_get_extent, mirror_num);
 277                 if (!ret &&
 278                     !verify_parent_transid(io_tree, eb, parent_transid))
 279                         return ret;
 280 printk("read extent buffer pages failed with ret %d mirror no %d\n", ret, mirror_num);
 281                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
 282                                               eb->start, eb->len);
 283                 if (num_copies == 1)
 284                         return ret;
 285
 286                 mirror_num++;
 287                 if (mirror_num > num_copies)
 288                         return ret;
 289         }
 290         return -EIO;
 291 }
 292
 293 /*
 294  * checksum a dirty tree block before IO.  This has extra checks to make
 295  * sure we only fill in the checksum field in the first page of a multi-page block
 296  */
 297 int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 298 {
 299         struct extent_io_tree *tree;
 300         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
 301         u64 found_start;
 302         int found_level;
 303         unsigned long len;
 304         struct extent_buffer *eb;
 305         int ret;
 306
 307         tree = &BTRFS_I(page->mapping->host)->io_tree;
 308
 309         if (page->private == EXTENT_PAGE_PRIVATE)
 310                 goto out;
 311         if (!page->private)
 312                 goto out;
 313         len = page->private >> 2;
 314         if (len == 0) {
 315                 WARN_ON(1);
 316         }
 317         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 318         ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE,
 319                                              btrfs_header_generation(eb));
 320         BUG_ON(ret);
 321         found_start = btrfs_header_bytenr(eb);
 322         if (found_start != start) {
 323                 printk("warning: eb start incorrect %Lu buffer %Lu len %lu\n",
 324                        start, found_start, len);
 325                 WARN_ON(1);
 326                 goto err;
 327         }
 328         if (eb->first_page != page) {
 329                 printk("bad first page %lu %lu\n", eb->first_page->index,
 330                        page->index);
 331                 WARN_ON(1);
 332                 goto err;
 333         }
 334         if (!PageUptodate(page)) {
 335                 printk("csum not up to date page %lu\n", page->index);
 336                 WARN_ON(1);
 337                 goto err;
 338         }
 339         found_level = btrfs_header_level(eb);
 340
 341         csum_tree_block(root, eb, 0);
 342 err:
 343         free_extent_buffer(eb);
 344 out:
 345         return 0;
 346 }
 347
 348 int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
 349                                struct extent_state *state)
 350 {
 351         struct extent_io_tree *tree;
 352         u64 found_start;
 353         int found_level;
 354         unsigned long len;
 355         struct extent_buffer *eb;
 356         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 357         int ret = 0;
 358
 359         tree = &BTRFS_I(page->mapping->host)->io_tree;
 360         if (page->private == EXTENT_PAGE_PRIVATE)
 361                 goto out;
 362         if (!page->private)
 363                 goto out;
 364         len = page->private >> 2;
 365         if (len == 0) {
 366                 WARN_ON(1);
 367         }
 368         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 369
 370         found_start = btrfs_header_bytenr(eb);
 371         if (found_start != start) {
 372                 printk("bad tree block start %llu %llu\n",
 373                        (unsigned long long)found_start,
 374                        (unsigned long long)eb->start);
 375                 ret = -EIO;
 376                 goto err;
 377         }
 378         if (eb->first_page != page) {
 379                 printk("bad first page %lu %lu\n", eb->first_page->index,
 380                        page->index);
 381                 WARN_ON(1);
 382                 ret = -EIO;
 383                 goto err;
 384         }
 385         if (memcmp_extent_buffer(eb, root->fs_info->fsid,
 386                                  (unsigned long)btrfs_header_fsid(eb),
 387                                  BTRFS_FSID_SIZE)) {
 388                 printk("bad fsid on block %Lu\n", eb->start);
 389                 ret = -EIO;
 390                 goto err;
 391         }
 392         found_level = btrfs_header_level(eb);
 393
 394         ret = csum_tree_block(root, eb, 1);
 395         if (ret)
 396                 ret = -EIO;
 397
 398         end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
 399         end = eb->start + end - 1;
 400 err:
 401         free_extent_buffer(eb);
 402 out:
 403         return ret;
 404 }
 405
 406 static void end_workqueue_bio(struct bio *bio, int err)
 407 {
 408         struct end_io_wq *end_io_wq = bio->bi_private;
 409         struct btrfs_fs_info *fs_info;
 410
 411         fs_info = end_io_wq->info;
 412         end_io_wq->error = err;
 413         end_io_wq->work.func = end_workqueue_fn;
 414         end_io_wq->work.flags = 0;
 415         if (bio->bi_rw & (1 << BIO_RW))
 416                 btrfs_queue_worker(&fs_info->endio_write_workers,
 417                                    &end_io_wq->work);
 418         else
 419                 btrfs_queue_worker(&fs_info->endio_workers, &end_io_wq->work);
 420 }
 421
 422 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 423                         int metadata)
 424 {
 425         struct end_io_wq *end_io_wq;
 426         end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
 427         if (!end_io_wq)
 428                 return -ENOMEM;
 429
 430         end_io_wq->private = bio->bi_private;
 431         end_io_wq->end_io = bio->bi_end_io;
 432         end_io_wq->info = info;
 433         end_io_wq->error = 0;
 434         end_io_wq->bio = bio;
 435         end_io_wq->metadata = metadata;
 436
 437         bio->bi_private = end_io_wq;
 438         bio->bi_end_io = end_workqueue_bio;
 439         return 0;
 440 }
 441
 442 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
 443 {
 444         unsigned long limit = min_t(unsigned long,
 445                                     info->workers.max_workers,
 446                                     info->fs_devices->open_devices);
 447         return 256 * limit;
 448 }
 449
 450 int btrfs_congested_async(struct btrfs_fs_info *info, int iodone)
 451 {
 452         return atomic_read(&info->nr_async_bios) >
 453                 btrfs_async_submit_limit(info);
 454 }
 455
 456 static void run_one_async_start(struct btrfs_work *work)
 457 {
 458         struct btrfs_fs_info *fs_info;
 459         struct async_submit_bio *async;
 460
 461         async = container_of(work, struct  async_submit_bio, work);
 462         fs_info = BTRFS_I(async->inode)->root->fs_info;
 463         async->submit_bio_start(async->inode, async->rw, async->bio,
 464                                async->mirror_num, async->bio_flags);
 465 }
 466
 467 static void run_one_async_done(struct btrfs_work *work)
 468 {
 469         struct btrfs_fs_info *fs_info;
 470         struct async_submit_bio *async;
 471         int limit;
 472
 473         async = container_of(work, struct  async_submit_bio, work);
 474         fs_info = BTRFS_I(async->inode)->root->fs_info;
 475
 476         limit = btrfs_async_submit_limit(fs_info);
 477         limit = limit * 2 / 3;
 478
 479         atomic_dec(&fs_info->nr_async_submits);
 480
 481         if (atomic_read(&fs_info->nr_async_submits) < limit &&
 482             waitqueue_active(&fs_info->async_submit_wait))
 483                 wake_up(&fs_info->async_submit_wait);
 484
 485         async->submit_bio_done(async->inode, async->rw, async->bio,
 486                                async->mirror_num, async->bio_flags);
 487 }
 488
 489 static void run_one_async_free(struct btrfs_work *work)
 490 {
 491         struct async_submit_bio *async;
 492
 493         async = container_of(work, struct  async_submit_bio, work);
 494         kfree(async);
 495 }
 496
 497 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
 498                         int rw, struct bio *bio, int mirror_num,
 499                         unsigned long bio_flags,
 500                         extent_submit_bio_hook_t *submit_bio_start,
 501                         extent_submit_bio_hook_t *submit_bio_done)
 502 {
 503         struct async_submit_bio *async;
 504         int limit = btrfs_async_submit_limit(fs_info);
 505
 506         async = kmalloc(sizeof(*async), GFP_NOFS);
 507         if (!async)
 508                 return -ENOMEM;
 509
 510         async->inode = inode;
 511         async->rw = rw;
 512         async->bio = bio;
 513         async->mirror_num = mirror_num;
 514         async->submit_bio_start = submit_bio_start;
 515         async->submit_bio_done = submit_bio_done;
 516
 517         async->work.func = run_one_async_start;
 518         async->work.ordered_func = run_one_async_done;
 519         async->work.ordered_free = run_one_async_free;
 520
 521         async->work.flags = 0;
 522         async->bio_flags = bio_flags;
 523
 524         while(atomic_read(&fs_info->async_submit_draining) &&
 525               atomic_read(&fs_info->nr_async_submits)) {
 526                 wait_event(fs_info->async_submit_wait,
 527                            (atomic_read(&fs_info->nr_async_submits) == 0));
 528         }
 529
 530         atomic_inc(&fs_info->nr_async_submits);
 531         btrfs_queue_worker(&fs_info->workers, &async->work);
 532
 533         if (atomic_read(&fs_info->nr_async_submits) > limit) {
 534                 wait_event_timeout(fs_info->async_submit_wait,
 535                            (atomic_read(&fs_info->nr_async_submits) < limit),
 536                            HZ/10);
 537
 538                 wait_event_timeout(fs_info->async_submit_wait,
 539                            (atomic_read(&fs_info->nr_async_bios) < limit),
 540                            HZ/10);
 541         }
 542         return 0;
 543 }
 544
 545 static int btree_csum_one_bio(struct bio *bio)
 546 {
 547         struct bio_vec *bvec = bio->bi_io_vec;
 548         int bio_index = 0;
 549         struct btrfs_root *root;
 550
 551         WARN_ON(bio->bi_vcnt <= 0);
 552         while(bio_index < bio->bi_vcnt) {
 553                 root = BTRFS_I(bvec->bv_page->mapping->host)->root;
 554                 csum_dirty_buffer(root, bvec->bv_page);
 555                 bio_index++;
 556                 bvec++;
 557         }
 558         return 0;
 559 }
 560
 561 static int __btree_submit_bio_start(struct inode *inode, int rw,
 562                                     struct bio *bio, int mirror_num,
 563                                     unsigned long bio_flags)
 564 {
 565         /*
 566          * when we're called for a write, we're already in the async
 567          * submission context.  Just jump into btrfs_map_bio
 568          */
 569         btree_csum_one_bio(bio);
 570         return 0;
 571 }
 572
 573 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
 574                                  int mirror_num, unsigned long bio_flags)
 575 {
 576         /*
 577          * when we're called for a write, we're already in the async
 578          * submission context.  Just jump into btrfs_map_bio
 579          */
 580         return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
 581 }
 582
 583 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 584                                  int mirror_num, unsigned long bio_flags)
 585 {
 586         /*
 587          * kthread helpers are used to submit writes so that checksumming
 588          * can happen in parallel across all CPUs
 589          */
 590         if (!(rw & (1 << BIO_RW))) {
 591                 int ret;
 592                 /*
 593                  * called for a read, do the setup so that checksum validation
 594                  * can happen in the async kernel threads
 595                  */
 596                 ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
 597                                           bio, 1);
 598                 BUG_ON(ret);
 599
 600                 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
 601                                      mirror_num, 1);
 602         }
 603         return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
 604                                    inode, rw, bio, mirror_num, 0,
 605                                    __btree_submit_bio_start,
 606                                    __btree_submit_bio_done);
 607 }
 608
 609 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 610 {
 611         struct extent_io_tree *tree;
 612         tree = &BTRFS_I(page->mapping->host)->io_tree;
 613
 614         if (current->flags & PF_MEMALLOC) {
 615                 redirty_page_for_writepage(wbc, page);
 616                 unlock_page(page);
 617                 return 0;
 618         }
 619         return extent_write_full_page(tree, page, btree_get_extent, wbc);
 620 }
 621
 622 static int btree_writepages(struct address_space *mapping,
 623                             struct writeback_control *wbc)
 624 {
 625         struct extent_io_tree *tree;
 626         tree = &BTRFS_I(mapping->host)->io_tree;
 627         if (wbc->sync_mode == WB_SYNC_NONE) {
 628                 u64 num_dirty;
 629                 u64 start = 0;
 630                 unsigned long thresh = 32 * 1024 * 1024;
 631
 632                 if (wbc->for_kupdate)
 633                         return 0;
 634
 635                 num_dirty = count_range_bits(tree, &start, (u64)-1,
 636                                              thresh, EXTENT_DIRTY);
 637                 if (num_dirty < thresh) {
 638                         return 0;
 639                 }
 640         }
 641         return extent_writepages(tree, mapping, btree_get_extent, wbc);
 642 }
 643
 644 int btree_readpage(struct file *file, struct page *page)
 645 {
 646         struct extent_io_tree *tree;
 647         tree = &BTRFS_I(page->mapping->host)->io_tree;
 648         return extent_read_full_page(tree, page, btree_get_extent);
 649 }
 650
 651 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
 652 {
 653         struct extent_io_tree *tree;
 654         struct extent_map_tree *map;
 655         int ret;
 656
 657         if (PageWriteback(page) || PageDirty(page))
 658             return 0;
 659
 660         tree = &BTRFS_I(page->mapping->host)->io_tree;
 661         map = &BTRFS_I(page->mapping->host)->extent_tree;
 662
 663         ret = try_release_extent_state(map, tree, page, gfp_flags);
 664         if (!ret) {
 665                 return 0;
 666         }
 667
 668         ret = try_release_extent_buffer(tree, page);
 669         if (ret == 1) {
 670                 ClearPagePrivate(page);
 671                 set_page_private(page, 0);
 672                 page_cache_release(page);
 673         }
 674
 675         return ret;
 676 }
 677
 678 static void btree_invalidatepage(struct page *page, unsigned long offset)
 679 {
 680         struct extent_io_tree *tree;
 681         tree = &BTRFS_I(page->mapping->host)->io_tree;
 682         extent_invalidatepage(tree, page, offset);
 683         btree_releasepage(page, GFP_NOFS);
 684         if (PagePrivate(page)) {
 685                 printk("warning page private not zero on page %Lu\n",
 686                        page_offset(page));
 687                 ClearPagePrivate(page);
 688                 set_page_private(page, 0);
 689                 page_cache_release(page);
 690         }
 691 }
 692
 693 #if 0
 694 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 695 {
 696         struct buffer_head *bh;
 697         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 698         struct buffer_head *head;
 699         if (!page_has_buffers(page)) {
 700                 create_empty_buffers(page, root->fs_info->sb->s_blocksize,
 701                                         (1 << BH_Dirty)|(1 << BH_Uptodate));
 702         }
 703         head = page_buffers(page);
 704         bh = head;
 705         do {
 706                 if (buffer_dirty(bh))
 707                         csum_tree_block(root, bh, 0);
 708                 bh = bh->b_this_page;
 709         } while (bh != head);
 710         return block_write_full_page(page, btree_get_block, wbc);
 711 }
 712 #endif
 713
 714 static struct address_space_operations btree_aops = {
 715         .readpage       = btree_readpage,
 716         .writepage      = btree_writepage,
 717         .writepages     = btree_writepages,
 718         .releasepage    = btree_releasepage,
 719         .invalidatepage = btree_invalidatepage,
 720         .sync_page      = block_sync_page,
 721 };
 722
 723 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
 724                          u64 parent_transid)
 725 {
 726         struct extent_buffer *buf = NULL;
 727         struct inode *btree_inode = root->fs_info->btree_inode;
 728         int ret = 0;
 729
 730         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 731         if (!buf)
 732                 return 0;
 733         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
 734                                  buf, 0, 0, btree_get_extent, 0);
 735         free_extent_buffer(buf);
 736         return ret;
 737 }
 738
 739 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
 740                                             u64 bytenr, u32 blocksize)
 741 {
 742         struct inode *btree_inode = root->fs_info->btree_inode;
 743         struct extent_buffer *eb;
 744         eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 745                                 bytenr, blocksize, GFP_NOFS);
 746         return eb;
 747 }
 748
 749 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 750                                                  u64 bytenr, u32 blocksize)
 751 {
 752         struct inode *btree_inode = root->fs_info->btree_inode;
 753         struct extent_buffer *eb;
 754
 755         eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 756                                  bytenr, blocksize, NULL, GFP_NOFS);
 757         return eb;
 758 }
 759
 760
 761 int btrfs_write_tree_block(struct extent_buffer *buf)
 762 {
 763         return btrfs_fdatawrite_range(buf->first_page->mapping, buf->start,
 764                                       buf->start + buf->len - 1, WB_SYNC_ALL);
 765 }
 766
 767 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
 768 {
 769         return btrfs_wait_on_page_writeback_range(buf->first_page->mapping,
 770                                   buf->start, buf->start + buf->len -1);
 771 }
 772
 773 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 774                                       u32 blocksize, u64 parent_transid)
 775 {
 776         struct extent_buffer *buf = NULL;
 777         struct inode *btree_inode = root->fs_info->btree_inode;
 778         struct extent_io_tree *io_tree;
 779         int ret;
 780
 781         io_tree = &BTRFS_I(btree_inode)->io_tree;
 782
 783         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 784         if (!buf)
 785                 return NULL;
 786
 787         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
 788
 789         if (ret == 0) {
 790                 buf->flags |= EXTENT_UPTODATE;
 791         } else {
 792                 WARN_ON(1);
 793         }
 794         return buf;
 795
 796 }
 797
 798 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 799                      struct extent_buffer *buf)
 800 {
 801         struct inode *btree_inode = root->fs_info->btree_inode;
 802         if (btrfs_header_generation(buf) ==
 803             root->fs_info->running_transaction->transid) {
 804                 WARN_ON(!btrfs_tree_locked(buf));
 805                 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
 806                                           buf);
 807         }
 808         return 0;
 809 }
 810
 811 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
 812                         u32 stripesize, struct btrfs_root *root,
 813                         struct btrfs_fs_info *fs_info,
 814                         u64 objectid)
 815 {
 816         root->node = NULL;
 817         root->inode = NULL;
 818         root->commit_root = NULL;
 819         root->ref_tree = NULL;
 820         root->sectorsize = sectorsize;
 821         root->nodesize = nodesize;
 822         root->leafsize = leafsize;
 823         root->stripesize = stripesize;
 824         root->ref_cows = 0;
 825         root->track_dirty = 0;
 826
 827         root->fs_info = fs_info;
 828         root->objectid = objectid;
 829         root->last_trans = 0;
 830         root->highest_inode = 0;
 831         root->last_inode_alloc = 0;
 832         root->name = NULL;
 833         root->in_sysfs = 0;
 834
 835         INIT_LIST_HEAD(&root->dirty_list);
 836         INIT_LIST_HEAD(&root->orphan_list);
 837         INIT_LIST_HEAD(&root->dead_list);
 838         spin_lock_init(&root->node_lock);
 839         spin_lock_init(&root->list_lock);
 840         mutex_init(&root->objectid_mutex);
 841         mutex_init(&root->log_mutex);
 842         extent_io_tree_init(&root->dirty_log_pages,
 843                              fs_info->btree_inode->i_mapping, GFP_NOFS);
 844
 845         btrfs_leaf_ref_tree_init(&root->ref_tree_struct);
 846         root->ref_tree = &root->ref_tree_struct;
 847
 848         memset(&root->root_key, 0, sizeof(root->root_key));
 849         memset(&root->root_item, 0, sizeof(root->root_item));
 850         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
 851         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
 852         root->defrag_trans_start = fs_info->generation;
 853         init_completion(&root->kobj_unregister);
 854         root->defrag_running = 0;
 855         root->defrag_level = 0;
 856         root->root_key.objectid = objectid;
 857         return 0;
 858 }
 859
 860 static int find_and_setup_root(struct btrfs_root *tree_root,
 861                                struct btrfs_fs_info *fs_info,
 862                                u64 objectid,
 863                                struct btrfs_root *root)
 864 {
 865         int ret;
 866         u32 blocksize;
 867         u64 generation;
 868
 869         __setup_root(tree_root->nodesize, tree_root->leafsize,
 870                      tree_root->sectorsize, tree_root->stripesize,
 871                      root, fs_info, objectid);
 872         ret = btrfs_find_last_root(tree_root, objectid,
 873                                    &root->root_item, &root->root_key);
 874         BUG_ON(ret);
 875
 876         generation = btrfs_root_generation(&root->root_item);
 877         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
 878         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
 879                                      blocksize, generation);
 880         BUG_ON(!root->node);
 881         return 0;
 882 }
 883
 884 int btrfs_free_log_root_tree(struct btrfs_trans_handle *trans,
 885                              struct btrfs_fs_info *fs_info)
 886 {
 887         struct extent_buffer *eb;
 888         struct btrfs_root *log_root_tree = fs_info->log_root_tree;
 889         u64 start = 0;
 890         u64 end = 0;
 891         int ret;
 892
 893         if (!log_root_tree)
 894                 return 0;
 895
 896         while(1) {
 897                 ret = find_first_extent_bit(&log_root_tree->dirty_log_pages,
 898                                     0, &start, &end, EXTENT_DIRTY);
 899                 if (ret)
 900                         break;
 901
 902                 clear_extent_dirty(&log_root_tree->dirty_log_pages,
 903                                    start, end, GFP_NOFS);
 904         }
 905         eb = fs_info->log_root_tree->node;
 906
 907         WARN_ON(btrfs_header_level(eb) != 0);
 908         WARN_ON(btrfs_header_nritems(eb) != 0);
 909
 910         ret = btrfs_free_reserved_extent(fs_info->tree_root,
 911                                 eb->start, eb->len);
 912         BUG_ON(ret);
 913
 914         free_extent_buffer(eb);
 915         kfree(fs_info->log_root_tree);
 916         fs_info->log_root_tree = NULL;
 917         return 0;
 918 }
 919
 920 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
 921                              struct btrfs_fs_info *fs_info)
 922 {
 923         struct btrfs_root *root;
 924         struct btrfs_root *tree_root = fs_info->tree_root;
 925
 926         root = kzalloc(sizeof(*root), GFP_NOFS);
 927         if (!root)
 928                 return -ENOMEM;
 929
 930         __setup_root(tree_root->nodesize, tree_root->leafsize,
 931                      tree_root->sectorsize, tree_root->stripesize,
 932                      root, fs_info, BTRFS_TREE_LOG_OBJECTID);
 933
 934         root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
 935         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
 936         root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
 937         root->ref_cows = 0;
 938
 939         root->node = btrfs_alloc_free_block(trans, root, root->leafsize,
 940                                             0, BTRFS_TREE_LOG_OBJECTID,
 941                                             trans->transid, 0, 0, 0);
 942
 943         btrfs_set_header_nritems(root->node, 0);
 944         btrfs_set_header_level(root->node, 0);
 945         btrfs_set_header_bytenr(root->node, root->node->start);
 946         btrfs_set_header_generation(root->node, trans->transid);
 947         btrfs_set_header_owner(root->node, BTRFS_TREE_LOG_OBJECTID);
 948
 949         write_extent_buffer(root->node, root->fs_info->fsid,
 950                             (unsigned long)btrfs_header_fsid(root->node),
 951                             BTRFS_FSID_SIZE);
 952         btrfs_mark_buffer_dirty(root->node);
 953         btrfs_tree_unlock(root->node);
 954         fs_info->log_root_tree = root;
 955         return 0;
 956 }
 957
 958 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
 959                                                struct btrfs_key *location)
 960 {
 961         struct btrfs_root *root;
 962         struct btrfs_fs_info *fs_info = tree_root->fs_info;
 963         struct btrfs_path *path;
 964         struct extent_buffer *l;
 965         u64 highest_inode;
 966         u64 generation;
 967         u32 blocksize;
 968         int ret = 0;
 969
 970         root = kzalloc(sizeof(*root), GFP_NOFS);
 971         if (!root)
 972                 return ERR_PTR(-ENOMEM);
 973         if (location->offset == (u64)-1) {
 974                 ret = find_and_setup_root(tree_root, fs_info,
 975                                           location->objectid, root);
 976                 if (ret) {
 977                         kfree(root);
 978                         return ERR_PTR(ret);
 979                 }
 980                 goto insert;
 981         }
 982
 983         __setup_root(tree_root->nodesize, tree_root->leafsize,
 984                      tree_root->sectorsize, tree_root->stripesize,
 985                      root, fs_info, location->objectid);
 986
 987         path = btrfs_alloc_path();
 988         BUG_ON(!path);
 989         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
 990         if (ret != 0) {
 991                 if (ret > 0)
 992                         ret = -ENOENT;
 993                 goto out;
 994         }
 995         l = path->nodes[0];
 996         read_extent_buffer(l, &root->root_item,
 997                btrfs_item_ptr_offset(l, path->slots[0]),
 998                sizeof(root->root_item));
 999         memcpy(&root->root_key, location, sizeof(*location));
1000         ret = 0;
1001 out:
1002         btrfs_release_path(root, path);
1003         btrfs_free_path(path);
1004         if (ret) {
1005                 kfree(root);
1006                 return ERR_PTR(ret);
1007         }
1008         generation = btrfs_root_generation(&root->root_item);
1009         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1010         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1011                                      blocksize, generation);
1012         BUG_ON(!root->node);
1013 insert:
1014         if (location->objectid != BTRFS_TREE_LOG_OBJECTID) {
1015                 root->ref_cows = 1;
1016                 ret = btrfs_find_highest_inode(root, &highest_inode);
1017                 if (ret == 0) {
1018                         root->highest_inode = highest_inode;
1019                         root->last_inode_alloc = highest_inode;
1020                 }
1021         }
1022         return root;
1023 }
1024
1025 struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
1026                                         u64 root_objectid)
1027 {
1028         struct btrfs_root *root;
1029
1030         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID)
1031                 return fs_info->tree_root;
1032         if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID)
1033                 return fs_info->extent_root;
1034
1035         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1036                                  (unsigned long)root_objectid);
1037         return root;
1038 }
1039
1040 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
1041                                               struct btrfs_key *location)
1042 {
1043         struct btrfs_root *root;
1044         int ret;
1045
1046         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1047                 return fs_info->tree_root;
1048         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1049                 return fs_info->extent_root;
1050         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1051                 return fs_info->chunk_root;
1052         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1053                 return fs_info->dev_root;
1054
1055         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1056                                  (unsigned long)location->objectid);
1057         if (root)
1058                 return root;
1059
1060         root = btrfs_read_fs_root_no_radix(fs_info->tree_root, location);
1061         if (IS_ERR(root))
1062                 return root;
1063         ret = radix_tree_insert(&fs_info->fs_roots_radix,
1064                                 (unsigned long)root->root_key.objectid,
1065                                 root);
1066         if (ret) {
1067                 free_extent_buffer(root->node);
1068                 kfree(root);
1069                 return ERR_PTR(ret);
1070         }
1071         ret = btrfs_find_dead_roots(fs_info->tree_root,
1072                                     root->root_key.objectid, root);
1073         BUG_ON(ret);
1074
1075         return root;
1076 }
1077
1078 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
1079                                       struct btrfs_key *location,
1080                                       const char *name, int namelen)
1081 {
1082         struct btrfs_root *root;
1083         int ret;
1084
1085         root = btrfs_read_fs_root_no_name(fs_info, location);
1086         if (!root)
1087                 return NULL;
1088
1089         if (root->in_sysfs)
1090                 return root;
1091
1092         ret = btrfs_set_root_name(root, name, namelen);
1093         if (ret) {
1094                 free_extent_buffer(root->node);
1095                 kfree(root);
1096                 return ERR_PTR(ret);
1097         }
1098
1099         ret = btrfs_sysfs_add_root(root);
1100         if (ret) {
1101                 free_extent_buffer(root->node);
1102                 kfree(root->name);
1103                 kfree(root);
1104                 return ERR_PTR(ret);
1105         }
1106         root->in_sysfs = 1;
1107         return root;
1108 }
1109 #if 0
1110 static int add_hasher(struct btrfs_fs_info *info, char *type) {
1111         struct btrfs_hasher *hasher;
1112
1113         hasher = kmalloc(sizeof(*hasher), GFP_NOFS);
1114         if (!hasher)
1115                 return -ENOMEM;
1116         hasher->hash_tfm = crypto_alloc_hash(type, 0, CRYPTO_ALG_ASYNC);
1117         if (!hasher->hash_tfm) {
1118                 kfree(hasher);
1119                 return -EINVAL;
1120         }
1121         spin_lock(&info->hash_lock);
1122         list_add(&hasher->list, &info->hashers);
1123         spin_unlock(&info->hash_lock);
1124         return 0;
1125 }
1126 #endif
1127
1128 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1129 {
1130         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1131         int ret = 0;
1132         struct list_head *cur;
1133         struct btrfs_device *device;
1134         struct backing_dev_info *bdi;
1135
1136         if ((bdi_bits & (1 << BDI_write_congested)) &&
1137             btrfs_congested_async(info, 0))
1138                 return 1;
1139
1140         list_for_each(cur, &info->fs_devices->devices) {
1141                 device = list_entry(cur, struct btrfs_device, dev_list);
1142                 if (!device->bdev)
1143                         continue;
1144                 bdi = blk_get_backing_dev_info(device->bdev);
1145                 if (bdi && bdi_congested(bdi, bdi_bits)) {
1146                         ret = 1;
1147                         break;
1148                 }
1149         }
1150         return ret;
1151 }
1152
1153 /*
1154  * this unplugs every device on the box, and it is only used when page
1155  * is null
1156  */
1157 static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1158 {
1159         struct list_head *cur;
1160         struct btrfs_device *device;
1161         struct btrfs_fs_info *info;
1162
1163         info = (struct btrfs_fs_info *)bdi->unplug_io_data;
1164         list_for_each(cur, &info->fs_devices->devices) {
1165                 device = list_entry(cur, struct btrfs_device, dev_list);
1166                 bdi = blk_get_backing_dev_info(device->bdev);
1167                 if (bdi->unplug_io_fn) {
1168                         bdi->unplug_io_fn(bdi, page);
1169                 }
1170         }
1171 }
1172
1173 void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1174 {
1175         struct inode *inode;
1176         struct extent_map_tree *em_tree;
1177         struct extent_map *em;
1178         struct address_space *mapping;
1179         u64 offset;
1180
1181         /* the generic O_DIRECT read code does this */
1182         if (!page) {
1183                 __unplug_io_fn(bdi, page);
1184                 return;
1185         }
1186
1187         /*
1188          * page->mapping may change at any time.  Get a consistent copy
1189          * and use that for everything below
1190          */
1191         smp_mb();
1192         mapping = page->mapping;
1193         if (!mapping)
1194                 return;
1195
1196         inode = mapping->host;
1197         offset = page_offset(page);
1198
1199         em_tree = &BTRFS_I(inode)->extent_tree;
1200         spin_lock(&em_tree->lock);
1201         em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
1202         spin_unlock(&em_tree->lock);
1203         if (!em) {
1204                 __unplug_io_fn(bdi, page);
1205                 return;
1206         }
1207
1208         if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1209                 free_extent_map(em);
1210                 __unplug_io_fn(bdi, page);
1211                 return;
1212         }
1213         offset = offset - em->start;
1214         btrfs_unplug_page(&BTRFS_I(inode)->root->fs_info->mapping_tree,
1215                           em->block_start + offset, page);
1216         free_extent_map(em);
1217 }
1218
1219 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1220 {
1221         bdi_init(bdi);
1222         bdi->ra_pages   = default_backing_dev_info.ra_pages;
1223         bdi->state              = 0;
1224         bdi->capabilities       = default_backing_dev_info.capabilities;
1225         bdi->unplug_io_fn       = btrfs_unplug_io_fn;
1226         bdi->unplug_io_data     = info;
1227         bdi->congested_fn       = btrfs_congested_fn;
1228         bdi->congested_data     = info;
1229         return 0;
1230 }
1231
1232 static int bio_ready_for_csum(struct bio *bio)
1233 {
1234         u64 length = 0;
1235         u64 buf_len = 0;
1236         u64 start = 0;
1237         struct page *page;
1238         struct extent_io_tree *io_tree = NULL;
1239         struct btrfs_fs_info *info = NULL;
1240         struct bio_vec *bvec;
1241         int i;
1242         int ret;
1243
1244         bio_for_each_segment(bvec, bio, i) {
1245                 page = bvec->bv_page;
1246                 if (page->private == EXTENT_PAGE_PRIVATE) {
1247                         length += bvec->bv_len;
1248                         continue;
1249                 }
1250                 if (!page->private) {
1251                         length += bvec->bv_len;
1252                         continue;
1253                 }
1254                 length = bvec->bv_len;
1255                 buf_len = page->private >> 2;
1256                 start = page_offset(page) + bvec->bv_offset;
1257                 io_tree = &BTRFS_I(page->mapping->host)->io_tree;
1258                 info = BTRFS_I(page->mapping->host)->root->fs_info;
1259         }
1260         /* are we fully contained in this bio? */
1261         if (buf_len <= length)
1262                 return 1;
1263
1264         ret = extent_range_uptodate(io_tree, start + length,
1265                                     start + buf_len - 1);
1266         if (ret == 1)
1267                 return ret;
1268         return ret;
1269 }
1270
1271 /*
1272  * called by the kthread helper functions to finally call the bio end_io
1273  * functions.  This is where read checksum verification actually happens
1274  */
1275 static void end_workqueue_fn(struct btrfs_work *work)
1276 {
1277         struct bio *bio;
1278         struct end_io_wq *end_io_wq;
1279         struct btrfs_fs_info *fs_info;
1280         int error;
1281
1282         end_io_wq = container_of(work, struct end_io_wq, work);
1283         bio = end_io_wq->bio;
1284         fs_info = end_io_wq->info;
1285
1286         /* metadata bios are special because the whole tree block must
1287          * be checksummed at once.  This makes sure the entire block is in
1288          * ram and up to date before trying to verify things.  For
1289          * blocksize <= pagesize, it is basically a noop
1290          */
1291         if (end_io_wq->metadata && !bio_ready_for_csum(bio)) {
1292                 btrfs_queue_worker(&fs_info->endio_workers,
1293                                    &end_io_wq->work);
1294                 return;
1295         }
1296         error = end_io_wq->error;
1297         bio->bi_private = end_io_wq->private;
1298         bio->bi_end_io = end_io_wq->end_io;
1299         kfree(end_io_wq);
1300         bio_endio(bio, error);
1301 }
1302
1303 static int cleaner_kthread(void *arg)
1304 {
1305         struct btrfs_root *root = arg;
1306
1307         do {
1308                 smp_mb();
1309                 if (root->fs_info->closing)
1310                         break;
1311
1312                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1313                 mutex_lock(&root->fs_info->cleaner_mutex);
1314                 btrfs_clean_old_snapshots(root);
1315                 mutex_unlock(&root->fs_info->cleaner_mutex);
1316
1317                 if (freezing(current)) {
1318                         refrigerator();
1319                 } else {
1320                         smp_mb();
1321                         if (root->fs_info->closing)
1322                                 break;
1323                         set_current_state(TASK_INTERRUPTIBLE);
1324                         schedule();
1325                         __set_current_state(TASK_RUNNING);
1326                 }
1327         } while (!kthread_should_stop());
1328         return 0;
1329 }
1330
1331 static int transaction_kthread(void *arg)
1332 {
1333         struct btrfs_root *root = arg;
1334         struct btrfs_trans_handle *trans;
1335         struct btrfs_transaction *cur;
1336         unsigned long now;
1337         unsigned long delay;
1338         int ret;
1339
1340         do {
1341                 smp_mb();
1342                 if (root->fs_info->closing)
1343                         break;
1344
1345                 delay = HZ * 30;
1346                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1347                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1348
1349                 if (root->fs_info->total_ref_cache_size > 20 * 1024 * 1024) {
1350                         printk("btrfs: total reference cache size %Lu\n",
1351                                 root->fs_info->total_ref_cache_size);
1352                 }
1353
1354                 mutex_lock(&root->fs_info->trans_mutex);
1355                 cur = root->fs_info->running_transaction;
1356                 if (!cur) {
1357                         mutex_unlock(&root->fs_info->trans_mutex);
1358                         goto sleep;
1359                 }
1360
1361                 now = get_seconds();
1362                 if (now < cur->start_time || now - cur->start_time < 30) {
1363                         mutex_unlock(&root->fs_info->trans_mutex);
1364                         delay = HZ * 5;
1365                         goto sleep;
1366                 }
1367                 mutex_unlock(&root->fs_info->trans_mutex);
1368                 trans = btrfs_start_transaction(root, 1);
1369                 ret = btrfs_commit_transaction(trans, root);
1370 sleep:
1371                 wake_up_process(root->fs_info->cleaner_kthread);
1372                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1373
1374                 if (freezing(current)) {
1375                         refrigerator();
1376                 } else {
1377                         if (root->fs_info->closing)
1378                                 break;
1379                         set_current_state(TASK_INTERRUPTIBLE);
1380                         schedule_timeout(delay);
1381                         __set_current_state(TASK_RUNNING);
1382                 }
1383         } while (!kthread_should_stop());
1384         return 0;
1385 }
1386
1387 struct btrfs_root *open_ctree(struct super_block *sb,
1388                               struct btrfs_fs_devices *fs_devices,
1389                               char *options)
1390 {
1391         u32 sectorsize;
1392         u32 nodesize;
1393         u32 leafsize;
1394         u32 blocksize;
1395         u32 stripesize;
1396         u64 generation;
1397         struct buffer_head *bh;
1398         struct btrfs_root *extent_root = kzalloc(sizeof(struct btrfs_root),
1399                                                  GFP_NOFS);
1400         struct btrfs_root *tree_root = kzalloc(sizeof(struct btrfs_root),
1401                                                GFP_NOFS);
1402         struct btrfs_fs_info *fs_info = kzalloc(sizeof(*fs_info),
1403                                                 GFP_NOFS);
1404         struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root),
1405                                                 GFP_NOFS);
1406         struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root),
1407                                               GFP_NOFS);
1408         struct btrfs_root *log_tree_root;
1409
1410         int ret;
1411         int err = -EINVAL;
1412
1413         struct btrfs_super_block *disk_super;
1414
1415         if (!extent_root || !tree_root || !fs_info ||
1416             !chunk_root || !dev_root) {
1417                 err = -ENOMEM;
1418                 goto fail;
1419         }
1420         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
1421         INIT_LIST_HEAD(&fs_info->trans_list);
1422         INIT_LIST_HEAD(&fs_info->dead_roots);
1423         INIT_LIST_HEAD(&fs_info->hashers);
1424         INIT_LIST_HEAD(&fs_info->delalloc_inodes);
1425         spin_lock_init(&fs_info->hash_lock);
1426         spin_lock_init(&fs_info->delalloc_lock);
1427         spin_lock_init(&fs_info->new_trans_lock);
1428         spin_lock_init(&fs_info->ref_cache_lock);
1429
1430         init_completion(&fs_info->kobj_unregister);
1431         fs_info->tree_root = tree_root;
1432         fs_info->extent_root = extent_root;
1433         fs_info->chunk_root = chunk_root;
1434         fs_info->dev_root = dev_root;
1435         fs_info->fs_devices = fs_devices;
1436         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
1437         INIT_LIST_HEAD(&fs_info->space_info);
1438         btrfs_mapping_init(&fs_info->mapping_tree);
1439         atomic_set(&fs_info->nr_async_submits, 0);
1440         atomic_set(&fs_info->async_submit_draining, 0);
1441         atomic_set(&fs_info->nr_async_bios, 0);
1442         atomic_set(&fs_info->throttles, 0);
1443         atomic_set(&fs_info->throttle_gen, 0);
1444         fs_info->sb = sb;
1445         fs_info->max_extent = (u64)-1;
1446         fs_info->max_inline = 8192 * 1024;
1447         setup_bdi(fs_info, &fs_info->bdi);
1448         fs_info->btree_inode = new_inode(sb);
1449         fs_info->btree_inode->i_ino = 1;
1450         fs_info->btree_inode->i_nlink = 1;
1451
1452         fs_info->thread_pool_size = min(num_online_cpus() + 2, 8);
1453
1454         INIT_LIST_HEAD(&fs_info->ordered_extents);
1455         spin_lock_init(&fs_info->ordered_extent_lock);
1456
1457         sb->s_blocksize = 4096;
1458         sb->s_blocksize_bits = blksize_bits(4096);
1459
1460         /*
1461          * we set the i_size on the btree inode to the max possible int.
1462          * the real end of the address space is determined by all of
1463          * the devices in the system
1464          */
1465         fs_info->btree_inode->i_size = OFFSET_MAX;
1466         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
1467         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
1468
1469         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
1470                              fs_info->btree_inode->i_mapping,
1471                              GFP_NOFS);
1472         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree,
1473                              GFP_NOFS);
1474
1475         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
1476
1477         spin_lock_init(&fs_info->block_group_cache_lock);
1478         fs_info->block_group_cache_tree.rb_node = NULL;
1479
1480         extent_io_tree_init(&fs_info->pinned_extents,
1481                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1482         extent_io_tree_init(&fs_info->pending_del,
1483                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1484         extent_io_tree_init(&fs_info->extent_ins,
1485                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1486         fs_info->do_barriers = 1;
1487
1488         INIT_LIST_HEAD(&fs_info->dead_reloc_roots);
1489         btrfs_leaf_ref_tree_init(&fs_info->reloc_ref_tree);
1490         btrfs_leaf_ref_tree_init(&fs_info->shared_ref_tree);
1491
1492         BTRFS_I(fs_info->btree_inode)->root = tree_root;
1493         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
1494                sizeof(struct btrfs_key));
1495         insert_inode_hash(fs_info->btree_inode);
1496
1497         mutex_init(&fs_info->trans_mutex);
1498         mutex_init(&fs_info->tree_log_mutex);
1499         mutex_init(&fs_info->drop_mutex);
1500         mutex_init(&fs_info->extent_ins_mutex);
1501         mutex_init(&fs_info->pinned_mutex);
1502         mutex_init(&fs_info->chunk_mutex);
1503         mutex_init(&fs_info->transaction_kthread_mutex);
1504         mutex_init(&fs_info->cleaner_mutex);
1505         mutex_init(&fs_info->volume_mutex);
1506         mutex_init(&fs_info->tree_reloc_mutex);
1507         init_waitqueue_head(&fs_info->transaction_throttle);
1508         init_waitqueue_head(&fs_info->transaction_wait);
1509         init_waitqueue_head(&fs_info->async_submit_wait);
1510         init_waitqueue_head(&fs_info->tree_log_wait);
1511         atomic_set(&fs_info->tree_log_commit, 0);
1512         atomic_set(&fs_info->tree_log_writers, 0);
1513         fs_info->tree_log_transid = 0;
1514
1515 #if 0
1516         ret = add_hasher(fs_info, "crc32c");
1517         if (ret) {
1518                 printk("btrfs: failed hash setup, modprobe cryptomgr?\n");
1519                 err = -ENOMEM;
1520                 goto fail_iput;
1521         }
1522 #endif
1523         __setup_root(4096, 4096, 4096, 4096, tree_root,
1524                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
1525
1526
1527         bh = __bread(fs_devices->latest_bdev,
1528                      BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
1529         if (!bh)
1530                 goto fail_iput;
1531
1532         memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));
1533         brelse(bh);
1534
1535         memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
1536
1537         disk_super = &fs_info->super_copy;
1538         if (!btrfs_super_root(disk_super))
1539                 goto fail_sb_buffer;
1540
1541         err = btrfs_parse_options(tree_root, options);
1542         if (err)
1543                 goto fail_sb_buffer;
1544
1545         /*
1546          * we need to start all the end_io workers up front because the
1547          * queue work function gets called at interrupt time, and so it
1548          * cannot dynamically grow.
1549          */
1550         btrfs_init_workers(&fs_info->workers, "worker",
1551                            fs_info->thread_pool_size);
1552
1553         btrfs_init_workers(&fs_info->submit_workers, "submit",
1554                            min_t(u64, fs_devices->num_devices,
1555                            fs_info->thread_pool_size));
1556
1557         /* a higher idle thresh on the submit workers makes it much more
1558          * likely that bios will be send down in a sane order to the
1559          * devices
1560          */
1561         fs_info->submit_workers.idle_thresh = 64;
1562
1563         /* fs_info->workers is responsible for checksumming file data
1564          * blocks and metadata.  Using a larger idle thresh allows each
1565          * worker thread to operate on things in roughly the order they
1566          * were sent by the writeback daemons, improving overall locality
1567          * of the IO going down the pipe.
1568          */
1569         fs_info->workers.idle_thresh = 8;
1570         fs_info->workers.ordered = 1;
1571
1572         btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1);
1573         btrfs_init_workers(&fs_info->endio_workers, "endio",
1574                            fs_info->thread_pool_size);
1575         btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
1576                            fs_info->thread_pool_size);
1577
1578         /*
1579          * endios are largely parallel and should have a very
1580          * low idle thresh
1581          */
1582         fs_info->endio_workers.idle_thresh = 4;
1583         fs_info->endio_write_workers.idle_thresh = 64;
1584
1585         btrfs_start_workers(&fs_info->workers, 1);
1586         btrfs_start_workers(&fs_info->submit_workers, 1);
1587         btrfs_start_workers(&fs_info->fixup_workers, 1);
1588         btrfs_start_workers(&fs_info->endio_workers, fs_info->thread_pool_size);
1589         btrfs_start_workers(&fs_info->endio_write_workers,
1590                             fs_info->thread_pool_size);
1591
1592         err = -EINVAL;
1593         if (btrfs_super_num_devices(disk_super) > fs_devices->open_devices) {
1594                 printk("Btrfs: wanted %llu devices, but found %llu\n",
1595                        (unsigned long long)btrfs_super_num_devices(disk_super),
1596                        (unsigned long long)fs_devices->open_devices);
1597                 if (btrfs_test_opt(tree_root, DEGRADED))
1598                         printk("continuing in degraded mode\n");
1599                 else {
1600                         goto fail_sb_buffer;
1601                 }
1602         }
1603
1604         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
1605         fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
1606                                     4 * 1024 * 1024 / PAGE_CACHE_SIZE);
1607
1608         nodesize = btrfs_super_nodesize(disk_super);
1609         leafsize = btrfs_super_leafsize(disk_super);
1610         sectorsize = btrfs_super_sectorsize(disk_super);
1611         stripesize = btrfs_super_stripesize(disk_super);
1612         tree_root->nodesize = nodesize;
1613         tree_root->leafsize = leafsize;
1614         tree_root->sectorsize = sectorsize;
1615         tree_root->stripesize = stripesize;
1616
1617         sb->s_blocksize = sectorsize;
1618         sb->s_blocksize_bits = blksize_bits(sectorsize);
1619
1620         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
1621                     sizeof(disk_super->magic))) {
1622                 printk("btrfs: valid FS not found on %s\n", sb->s_id);
1623                 goto fail_sb_buffer;
1624         }
1625
1626         mutex_lock(&fs_info->chunk_mutex);
1627         ret = btrfs_read_sys_array(tree_root);
1628         mutex_unlock(&fs_info->chunk_mutex);
1629         if (ret) {
1630                 printk("btrfs: failed to read the system array on %s\n",
1631                        sb->s_id);
1632                 goto fail_sys_array;
1633         }
1634
1635         blocksize = btrfs_level_size(tree_root,
1636                                      btrfs_super_chunk_root_level(disk_super));
1637         generation = btrfs_super_chunk_root_generation(disk_super);
1638
1639         __setup_root(nodesize, leafsize, sectorsize, stripesize,
1640                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
1641
1642         chunk_root->node = read_tree_block(chunk_root,
1643                                            btrfs_super_chunk_root(disk_super),
1644                                            blocksize, generation);
1645         BUG_ON(!chunk_root->node);
1646
1647         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
1648                  (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
1649                  BTRFS_UUID_SIZE);
1650
1651         mutex_lock(&fs_info->chunk_mutex);
1652         ret = btrfs_read_chunk_tree(chunk_root);
1653         mutex_unlock(&fs_info->chunk_mutex);
1654         BUG_ON(ret);
1655
1656         btrfs_close_extra_devices(fs_devices);
1657
1658         blocksize = btrfs_level_size(tree_root,
1659                                      btrfs_super_root_level(disk_super));
1660         generation = btrfs_super_generation(disk_super);
1661
1662         tree_root->node = read_tree_block(tree_root,
1663                                           btrfs_super_root(disk_super),
1664                                           blocksize, generation);
1665         if (!tree_root->node)
1666                 goto fail_sb_buffer;
1667
1668
1669         ret = find_and_setup_root(tree_root, fs_info,
1670                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
1671         if (ret)
1672                 goto fail_tree_root;
1673         extent_root->track_dirty = 1;
1674
1675         ret = find_and_setup_root(tree_root, fs_info,
1676                                   BTRFS_DEV_TREE_OBJECTID, dev_root);
1677         dev_root->track_dirty = 1;
1678
1679         if (ret)
1680                 goto fail_extent_root;
1681
1682         btrfs_read_block_groups(extent_root);
1683
1684         fs_info->generation = btrfs_super_generation(disk_super) + 1;
1685         fs_info->data_alloc_profile = (u64)-1;
1686         fs_info->metadata_alloc_profile = (u64)-1;
1687         fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
1688         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
1689                                                "btrfs-cleaner");
1690         if (!fs_info->cleaner_kthread)
1691                 goto fail_extent_root;
1692
1693         fs_info->transaction_kthread = kthread_run(transaction_kthread,
1694                                                    tree_root,
1695                                                    "btrfs-transaction");
1696         if (!fs_info->transaction_kthread)
1697                 goto fail_cleaner;
1698
1699         if (btrfs_super_log_root(disk_super) != 0) {
1700                 u32 blocksize;
1701                 u64 bytenr = btrfs_super_log_root(disk_super);
1702
1703                 blocksize =
1704                      btrfs_level_size(tree_root,
1705                                       btrfs_super_log_root_level(disk_super));
1706
1707                 log_tree_root = kzalloc(sizeof(struct btrfs_root),
1708                                                       GFP_NOFS);
1709
1710                 __setup_root(nodesize, leafsize, sectorsize, stripesize,
1711                              log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1712
1713                 log_tree_root->node = read_tree_block(tree_root, bytenr,
1714                                                       blocksize,
1715                                                       generation + 1);
1716                 ret = btrfs_recover_log_trees(log_tree_root);
1717                 BUG_ON(ret);
1718         }
1719         fs_info->last_trans_committed = btrfs_super_generation(disk_super);
1720
1721         ret = btrfs_cleanup_reloc_trees(tree_root);
1722         BUG_ON(ret);
1723
1724         return tree_root;
1725
1726 fail_cleaner:
1727         kthread_stop(fs_info->cleaner_kthread);
1728 fail_extent_root:
1729         free_extent_buffer(extent_root->node);
1730 fail_tree_root:
1731         free_extent_buffer(tree_root->node);
1732 fail_sys_array:
1733 fail_sb_buffer:
1734         btrfs_stop_workers(&fs_info->fixup_workers);
1735         btrfs_stop_workers(&fs_info->workers);
1736         btrfs_stop_workers(&fs_info->endio_workers);
1737         btrfs_stop_workers(&fs_info->endio_write_workers);
1738         btrfs_stop_workers(&fs_info->submit_workers);
1739 fail_iput:
1740         iput(fs_info->btree_inode);
1741 fail:
1742         btrfs_close_devices(fs_info->fs_devices);
1743         btrfs_mapping_tree_free(&fs_info->mapping_tree);
1744
1745         kfree(extent_root);
1746         kfree(tree_root);
1747         bdi_destroy(&fs_info->bdi);
1748         kfree(fs_info);
1749         kfree(chunk_root);
1750         kfree(dev_root);
1751         return ERR_PTR(err);
1752 }
1753
1754 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
1755 {
1756         char b[BDEVNAME_SIZE];
1757
1758         if (uptodate) {
1759                 set_buffer_uptodate(bh);
1760         } else {
1761                 if (!buffer_eopnotsupp(bh) && printk_ratelimit()) {
1762                         printk(KERN_WARNING "lost page write due to "
1763                                         "I/O error on %s\n",
1764                                        bdevname(bh->b_bdev, b));
1765                 }
1766                 /* note, we dont' set_buffer_write_io_error because we have
1767                  * our own ways of dealing with the IO errors
1768                  */
1769                 clear_buffer_uptodate(bh);
1770         }
1771         unlock_buffer(bh);
1772         put_bh(bh);
1773 }
1774
1775 int write_all_supers(struct btrfs_root *root)
1776 {
1777         struct list_head *cur;
1778         struct list_head *head = &root->fs_info->fs_devices->devices;
1779         struct btrfs_device *dev;
1780         struct btrfs_super_block *sb;
1781         struct btrfs_dev_item *dev_item;
1782         struct buffer_head *bh;
1783         int ret;
1784         int do_barriers;
1785         int max_errors;
1786         int total_errors = 0;
1787         u32 crc;
1788         u64 flags;
1789
1790         max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
1791         do_barriers = !btrfs_test_opt(root, NOBARRIER);
1792
1793         sb = &root->fs_info->super_for_commit;
1794         dev_item = &sb->dev_item;
1795         list_for_each(cur, head) {
1796                 dev = list_entry(cur, struct btrfs_device, dev_list);
1797                 if (!dev->bdev) {
1798                         total_errors++;
1799                         continue;
1800                 }
1801                 if (!dev->in_fs_metadata)
1802                         continue;
1803
1804                 btrfs_set_stack_device_type(dev_item, dev->type);
1805                 btrfs_set_stack_device_id(dev_item, dev->devid);
1806                 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
1807                 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
1808                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
1809                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
1810                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
1811                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
1812                 flags = btrfs_super_flags(sb);
1813                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
1814
1815
1816                 crc = ~(u32)0;
1817                 crc = btrfs_csum_data(root, (char *)sb + BTRFS_CSUM_SIZE, crc,
1818                                       BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
1819                 btrfs_csum_final(crc, sb->csum);
1820
1821                 bh = __getblk(dev->bdev, BTRFS_SUPER_INFO_OFFSET / 4096,
1822                               BTRFS_SUPER_INFO_SIZE);
1823
1824                 memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
1825                 dev->pending_io = bh;
1826
1827                 get_bh(bh);
1828                 set_buffer_uptodate(bh);
1829                 lock_buffer(bh);
1830                 bh->b_end_io = btrfs_end_buffer_write_sync;
1831
1832                 if (do_barriers && dev->barriers) {
1833                         ret = submit_bh(WRITE_BARRIER, bh);
1834                         if (ret == -EOPNOTSUPP) {
1835                                 printk("btrfs: disabling barriers on dev %s\n",
1836                                        dev->name);
1837                                 set_buffer_uptodate(bh);
1838                                 dev->barriers = 0;
1839                                 get_bh(bh);
1840                                 lock_buffer(bh);
1841                                 ret = submit_bh(WRITE, bh);
1842                         }
1843                 } else {
1844                         ret = submit_bh(WRITE, bh);
1845                 }
1846                 if (ret)
1847                         total_errors++;
1848         }
1849         if (total_errors > max_errors) {
1850                 printk("btrfs: %d errors while writing supers\n", total_errors);
1851                 BUG();
1852         }
1853         total_errors = 0;
1854
1855         list_for_each(cur, head) {
1856                 dev = list_entry(cur, struct btrfs_device, dev_list);
1857                 if (!dev->bdev)
1858                         continue;
1859                 if (!dev->in_fs_metadata)
1860                         continue;
1861
1862                 BUG_ON(!dev->pending_io);
1863                 bh = dev->pending_io;
1864                 wait_on_buffer(bh);
1865                 if (!buffer_uptodate(dev->pending_io)) {
1866                         if (do_barriers && dev->barriers) {
1867                                 printk("btrfs: disabling barriers on dev %s\n",
1868                                        dev->name);
1869                                 set_buffer_uptodate(bh);
1870                                 get_bh(bh);
1871                                 lock_buffer(bh);
1872                                 dev->barriers = 0;
1873                                 ret = submit_bh(WRITE, bh);
1874                                 BUG_ON(ret);
1875                                 wait_on_buffer(bh);
1876                                 if (!buffer_uptodate(bh))
1877                                         total_errors++;
1878                         } else {
1879                                 total_errors++;
1880                         }
1881
1882                 }
1883                 dev->pending_io = NULL;
1884                 brelse(bh);
1885         }
1886         if (total_errors > max_errors) {
1887                 printk("btrfs: %d errors while writing supers\n", total_errors);
1888                 BUG();
1889         }
1890         return 0;
1891 }
1892
1893 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
1894                       *root)
1895 {
1896         int ret;
1897
1898         ret = write_all_supers(root);
1899         return ret;
1900 }
1901
1902 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
1903 {
1904         radix_tree_delete(&fs_info->fs_roots_radix,
1905                           (unsigned long)root->root_key.objectid);
1906         if (root->in_sysfs)
1907                 btrfs_sysfs_del_root(root);
1908         if (root->inode)
1909                 iput(root->inode);
1910         if (root->node)
1911                 free_extent_buffer(root->node);
1912         if (root->commit_root)
1913                 free_extent_buffer(root->commit_root);
1914         if (root->name)
1915                 kfree(root->name);
1916         kfree(root);
1917         return 0;
1918 }
1919
1920 static int del_fs_roots(struct btrfs_fs_info *fs_info)
1921 {
1922         int ret;
1923         struct btrfs_root *gang[8];
1924         int i;
1925
1926         while(1) {
1927                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
1928                                              (void **)gang, 0,
1929                                              ARRAY_SIZE(gang));
1930                 if (!ret)
1931                         break;
1932                 for (i = 0; i < ret; i++)
1933                         btrfs_free_fs_root(fs_info, gang[i]);
1934         }
1935         return 0;
1936 }
1937
1938 int close_ctree(struct btrfs_root *root)
1939 {
1940         int ret;
1941         struct btrfs_trans_handle *trans;
1942         struct btrfs_fs_info *fs_info = root->fs_info;
1943
1944         fs_info->closing = 1;
1945         smp_mb();
1946
1947         kthread_stop(root->fs_info->transaction_kthread);
1948         kthread_stop(root->fs_info->cleaner_kthread);
1949
1950         btrfs_clean_old_snapshots(root);
1951         trans = btrfs_start_transaction(root, 1);
1952         ret = btrfs_commit_transaction(trans, root);
1953         /* run commit again to  drop the original snapshot */
1954         trans = btrfs_start_transaction(root, 1);
1955         btrfs_commit_transaction(trans, root);
1956         ret = btrfs_write_and_wait_transaction(NULL, root);
1957         BUG_ON(ret);
1958
1959         write_ctree_super(NULL, root);
1960
1961         if (fs_info->delalloc_bytes) {
1962                 printk("btrfs: at unmount delalloc count %Lu\n",
1963                        fs_info->delalloc_bytes);
1964         }
1965         if (fs_info->total_ref_cache_size) {
1966                 printk("btrfs: at umount reference cache size %Lu\n",
1967                         fs_info->total_ref_cache_size);
1968         }
1969
1970         if (fs_info->extent_root->node)
1971                 free_extent_buffer(fs_info->extent_root->node);
1972
1973         if (fs_info->tree_root->node)
1974                 free_extent_buffer(fs_info->tree_root->node);
1975
1976         if (root->fs_info->chunk_root->node);
1977                 free_extent_buffer(root->fs_info->chunk_root->node);
1978
1979         if (root->fs_info->dev_root->node);
1980                 free_extent_buffer(root->fs_info->dev_root->node);
1981
1982         btrfs_free_block_groups(root->fs_info);
1983         fs_info->closing = 2;
1984         del_fs_roots(fs_info);
1985
1986         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
1987
1988         truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
1989
1990         btrfs_stop_workers(&fs_info->fixup_workers);
1991         btrfs_stop_workers(&fs_info->workers);
1992         btrfs_stop_workers(&fs_info->endio_workers);
1993         btrfs_stop_workers(&fs_info->endio_write_workers);
1994         btrfs_stop_workers(&fs_info->submit_workers);
1995
1996         iput(fs_info->btree_inode);
1997 #if 0
1998         while(!list_empty(&fs_info->hashers)) {
1999                 struct btrfs_hasher *hasher;
2000                 hasher = list_entry(fs_info->hashers.next, struct btrfs_hasher,
2001                                     hashers);
2002                 list_del(&hasher->hashers);
2003                 crypto_free_hash(&fs_info->hash_tfm);
2004                 kfree(hasher);
2005         }
2006 #endif
2007         btrfs_close_devices(fs_info->fs_devices);
2008         btrfs_mapping_tree_free(&fs_info->mapping_tree);
2009
2010         bdi_destroy(&fs_info->bdi);
2011
2012         kfree(fs_info->extent_root);
2013         kfree(fs_info->tree_root);
2014         kfree(fs_info->chunk_root);
2015         kfree(fs_info->dev_root);
2016         return 0;
2017 }
2018
2019 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
2020 {
2021         int ret;
2022         struct inode *btree_inode = buf->first_page->mapping->host;
2023
2024         ret = extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf);
2025         if (!ret)
2026                 return ret;
2027
2028         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
2029                                     parent_transid);
2030         return !ret;
2031 }
2032
2033 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
2034 {
2035         struct inode *btree_inode = buf->first_page->mapping->host;
2036         return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
2037                                           buf);
2038 }
2039
2040 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
2041 {
2042         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2043         u64 transid = btrfs_header_generation(buf);
2044         struct inode *btree_inode = root->fs_info->btree_inode;
2045
2046         WARN_ON(!btrfs_tree_locked(buf));
2047         if (transid != root->fs_info->generation) {
2048                 printk(KERN_CRIT "transid mismatch buffer %llu, found %Lu running %Lu\n",
2049                         (unsigned long long)buf->start,
2050                         transid, root->fs_info->generation);
2051                 WARN_ON(1);
2052         }
2053         set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree, buf);
2054 }
2055
2056 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
2057 {
2058         /*
2059          * looks as though older kernels can get into trouble with
2060          * this code, they end up stuck in balance_dirty_pages forever
2061          */
2062         struct extent_io_tree *tree;
2063         u64 num_dirty;
2064         u64 start = 0;
2065         unsigned long thresh = 96 * 1024 * 1024;
2066         tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
2067
2068         if (current_is_pdflush() || current->flags & PF_MEMALLOC)
2069                 return;
2070
2071         num_dirty = count_range_bits(tree, &start, (u64)-1,
2072                                      thresh, EXTENT_DIRTY);
2073         if (num_dirty > thresh) {
2074                 balance_dirty_pages_ratelimited_nr(
2075                                    root->fs_info->btree_inode->i_mapping, 1);
2076         }
2077         return;
2078 }
2079
2080 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
2081 {
2082         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2083         int ret;
2084         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
2085         if (ret == 0) {
2086                 buf->flags |= EXTENT_UPTODATE;
2087         }
2088         return ret;
2089 }
2090
2091 int btree_lock_page_hook(struct page *page)
2092 {
2093         struct inode *inode = page->mapping->host;
2094         struct btrfs_root *root = BTRFS_I(inode)->root;
2095         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2096         struct extent_buffer *eb;
2097         unsigned long len;
2098         u64 bytenr = page_offset(page);
2099
2100         if (page->private == EXTENT_PAGE_PRIVATE)
2101                 goto out;
2102
2103         len = page->private >> 2;
2104         eb = find_extent_buffer(io_tree, bytenr, len, GFP_NOFS);
2105         if (!eb)
2106                 goto out;
2107
2108         btrfs_tree_lock(eb);
2109         spin_lock(&root->fs_info->hash_lock);
2110         btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
2111         spin_unlock(&root->fs_info->hash_lock);
2112         btrfs_tree_unlock(eb);
2113         free_extent_buffer(eb);
2114 out:
2115         lock_page(page);
2116         return 0;
2117 }
2118
2119 static struct extent_io_ops btree_extent_io_ops = {
2120         .write_cache_pages_lock_hook = btree_lock_page_hook,
2121         .readpage_end_io_hook = btree_readpage_end_io_hook,
2122         .submit_bio_hook = btree_submit_bio_hook,
2123         /* note we're sharing with inode.c for the merge bio hook */
2124         .merge_bio_hook = btrfs_merge_bio_hook,
2125 };