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