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 static int check_tree_block_fsid(struct btrfs_root *root,
 349                                  struct extent_buffer *eb)
 350 {
 351         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
 352         u8 fsid[BTRFS_UUID_SIZE];
 353         int ret = 1;
 354
 355         read_extent_buffer(eb, fsid, (unsigned long)btrfs_header_fsid(eb),
 356                            BTRFS_FSID_SIZE);
 357         while (fs_devices) {
 358                 if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
 359                         ret = 0;
 360                         break;
 361                 }
 362                 fs_devices = fs_devices->seed;
 363         }
 364         return ret;
 365 }
 366
 367 int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
 368                                struct extent_state *state)
 369 {
 370         struct extent_io_tree *tree;
 371         u64 found_start;
 372         int found_level;
 373         unsigned long len;
 374         struct extent_buffer *eb;
 375         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 376         int ret = 0;
 377
 378         tree = &BTRFS_I(page->mapping->host)->io_tree;
 379         if (page->private == EXTENT_PAGE_PRIVATE)
 380                 goto out;
 381         if (!page->private)
 382                 goto out;
 383         len = page->private >> 2;
 384         if (len == 0) {
 385                 WARN_ON(1);
 386         }
 387         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 388
 389         found_start = btrfs_header_bytenr(eb);
 390         if (found_start != start) {
 391                 printk("bad tree block start %llu %llu\n",
 392                        (unsigned long long)found_start,
 393                        (unsigned long long)eb->start);
 394                 ret = -EIO;
 395                 goto err;
 396         }
 397         if (eb->first_page != page) {
 398                 printk("bad first page %lu %lu\n", eb->first_page->index,
 399                        page->index);
 400                 WARN_ON(1);
 401                 ret = -EIO;
 402                 goto err;
 403         }
 404         if (check_tree_block_fsid(root, eb)) {
 405                 printk("bad fsid on block %Lu\n", eb->start);
 406                 ret = -EIO;
 407                 goto err;
 408         }
 409         found_level = btrfs_header_level(eb);
 410
 411         ret = csum_tree_block(root, eb, 1);
 412         if (ret)
 413                 ret = -EIO;
 414
 415         end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
 416         end = eb->start + end - 1;
 417 err:
 418         free_extent_buffer(eb);
 419 out:
 420         return ret;
 421 }
 422
 423 static void end_workqueue_bio(struct bio *bio, int err)
 424 {
 425         struct end_io_wq *end_io_wq = bio->bi_private;
 426         struct btrfs_fs_info *fs_info;
 427
 428         fs_info = end_io_wq->info;
 429         end_io_wq->error = err;
 430         end_io_wq->work.func = end_workqueue_fn;
 431         end_io_wq->work.flags = 0;
 432         if (bio->bi_rw & (1 << BIO_RW))
 433                 btrfs_queue_worker(&fs_info->endio_write_workers,
 434                                    &end_io_wq->work);
 435         else
 436                 btrfs_queue_worker(&fs_info->endio_workers, &end_io_wq->work);
 437 }
 438
 439 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 440                         int metadata)
 441 {
 442         struct end_io_wq *end_io_wq;
 443         end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
 444         if (!end_io_wq)
 445                 return -ENOMEM;
 446
 447         end_io_wq->private = bio->bi_private;
 448         end_io_wq->end_io = bio->bi_end_io;
 449         end_io_wq->info = info;
 450         end_io_wq->error = 0;
 451         end_io_wq->bio = bio;
 452         end_io_wq->metadata = metadata;
 453
 454         bio->bi_private = end_io_wq;
 455         bio->bi_end_io = end_workqueue_bio;
 456         return 0;
 457 }
 458
 459 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
 460 {
 461         unsigned long limit = min_t(unsigned long,
 462                                     info->workers.max_workers,
 463                                     info->fs_devices->open_devices);
 464         return 256 * limit;
 465 }
 466
 467 int btrfs_congested_async(struct btrfs_fs_info *info, int iodone)
 468 {
 469         return atomic_read(&info->nr_async_bios) >
 470                 btrfs_async_submit_limit(info);
 471 }
 472
 473 static void run_one_async_start(struct btrfs_work *work)
 474 {
 475         struct btrfs_fs_info *fs_info;
 476         struct async_submit_bio *async;
 477
 478         async = container_of(work, struct  async_submit_bio, work);
 479         fs_info = BTRFS_I(async->inode)->root->fs_info;
 480         async->submit_bio_start(async->inode, async->rw, async->bio,
 481                                async->mirror_num, async->bio_flags);
 482 }
 483
 484 static void run_one_async_done(struct btrfs_work *work)
 485 {
 486         struct btrfs_fs_info *fs_info;
 487         struct async_submit_bio *async;
 488         int limit;
 489
 490         async = container_of(work, struct  async_submit_bio, work);
 491         fs_info = BTRFS_I(async->inode)->root->fs_info;
 492
 493         limit = btrfs_async_submit_limit(fs_info);
 494         limit = limit * 2 / 3;
 495
 496         atomic_dec(&fs_info->nr_async_submits);
 497
 498         if (atomic_read(&fs_info->nr_async_submits) < limit &&
 499             waitqueue_active(&fs_info->async_submit_wait))
 500                 wake_up(&fs_info->async_submit_wait);
 501
 502         async->submit_bio_done(async->inode, async->rw, async->bio,
 503                                async->mirror_num, async->bio_flags);
 504 }
 505
 506 static void run_one_async_free(struct btrfs_work *work)
 507 {
 508         struct async_submit_bio *async;
 509
 510         async = container_of(work, struct  async_submit_bio, work);
 511         kfree(async);
 512 }
 513
 514 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
 515                         int rw, struct bio *bio, int mirror_num,
 516                         unsigned long bio_flags,
 517                         extent_submit_bio_hook_t *submit_bio_start,
 518                         extent_submit_bio_hook_t *submit_bio_done)
 519 {
 520         struct async_submit_bio *async;
 521         int limit = btrfs_async_submit_limit(fs_info);
 522
 523         async = kmalloc(sizeof(*async), GFP_NOFS);
 524         if (!async)
 525                 return -ENOMEM;
 526
 527         async->inode = inode;
 528         async->rw = rw;
 529         async->bio = bio;
 530         async->mirror_num = mirror_num;
 531         async->submit_bio_start = submit_bio_start;
 532         async->submit_bio_done = submit_bio_done;
 533
 534         async->work.func = run_one_async_start;
 535         async->work.ordered_func = run_one_async_done;
 536         async->work.ordered_free = run_one_async_free;
 537
 538         async->work.flags = 0;
 539         async->bio_flags = bio_flags;
 540
 541         while(atomic_read(&fs_info->async_submit_draining) &&
 542               atomic_read(&fs_info->nr_async_submits)) {
 543                 wait_event(fs_info->async_submit_wait,
 544                            (atomic_read(&fs_info->nr_async_submits) == 0));
 545         }
 546
 547         atomic_inc(&fs_info->nr_async_submits);
 548         btrfs_queue_worker(&fs_info->workers, &async->work);
 549
 550         if (atomic_read(&fs_info->nr_async_submits) > limit) {
 551                 wait_event_timeout(fs_info->async_submit_wait,
 552                            (atomic_read(&fs_info->nr_async_submits) < limit),
 553                            HZ/10);
 554
 555                 wait_event_timeout(fs_info->async_submit_wait,
 556                            (atomic_read(&fs_info->nr_async_bios) < limit),
 557                            HZ/10);
 558         }
 559
 560         while(atomic_read(&fs_info->async_submit_draining) &&
 561               atomic_read(&fs_info->nr_async_submits)) {
 562                 wait_event(fs_info->async_submit_wait,
 563                            (atomic_read(&fs_info->nr_async_submits) == 0));
 564         }
 565
 566         return 0;
 567 }
 568
 569 static int btree_csum_one_bio(struct bio *bio)
 570 {
 571         struct bio_vec *bvec = bio->bi_io_vec;
 572         int bio_index = 0;
 573         struct btrfs_root *root;
 574
 575         WARN_ON(bio->bi_vcnt <= 0);
 576         while(bio_index < bio->bi_vcnt) {
 577                 root = BTRFS_I(bvec->bv_page->mapping->host)->root;
 578                 csum_dirty_buffer(root, bvec->bv_page);
 579                 bio_index++;
 580                 bvec++;
 581         }
 582         return 0;
 583 }
 584
 585 static int __btree_submit_bio_start(struct inode *inode, int rw,
 586                                     struct bio *bio, int mirror_num,
 587                                     unsigned long bio_flags)
 588 {
 589         /*
 590          * when we're called for a write, we're already in the async
 591          * submission context.  Just jump into btrfs_map_bio
 592          */
 593         btree_csum_one_bio(bio);
 594         return 0;
 595 }
 596
 597 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
 598                                  int mirror_num, unsigned long bio_flags)
 599 {
 600         /*
 601          * when we're called for a write, we're already in the async
 602          * submission context.  Just jump into btrfs_map_bio
 603          */
 604         return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
 605 }
 606
 607 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 608                                  int mirror_num, unsigned long bio_flags)
 609 {
 610         /*
 611          * kthread helpers are used to submit writes so that checksumming
 612          * can happen in parallel across all CPUs
 613          */
 614         if (!(rw & (1 << BIO_RW))) {
 615                 int ret;
 616                 /*
 617                  * called for a read, do the setup so that checksum validation
 618                  * can happen in the async kernel threads
 619                  */
 620                 ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
 621                                           bio, 1);
 622                 BUG_ON(ret);
 623
 624                 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
 625                                      mirror_num, 0);
 626         }
 627         return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
 628                                    inode, rw, bio, mirror_num, 0,
 629                                    __btree_submit_bio_start,
 630                                    __btree_submit_bio_done);
 631 }
 632
 633 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 634 {
 635         struct extent_io_tree *tree;
 636         tree = &BTRFS_I(page->mapping->host)->io_tree;
 637
 638         if (current->flags & PF_MEMALLOC) {
 639                 redirty_page_for_writepage(wbc, page);
 640                 unlock_page(page);
 641                 return 0;
 642         }
 643         return extent_write_full_page(tree, page, btree_get_extent, wbc);
 644 }
 645
 646 static int btree_writepages(struct address_space *mapping,
 647                             struct writeback_control *wbc)
 648 {
 649         struct extent_io_tree *tree;
 650         tree = &BTRFS_I(mapping->host)->io_tree;
 651         if (wbc->sync_mode == WB_SYNC_NONE) {
 652                 u64 num_dirty;
 653                 u64 start = 0;
 654                 unsigned long thresh = 32 * 1024 * 1024;
 655
 656                 if (wbc->for_kupdate)
 657                         return 0;
 658
 659                 num_dirty = count_range_bits(tree, &start, (u64)-1,
 660                                              thresh, EXTENT_DIRTY);
 661                 if (num_dirty < thresh) {
 662                         return 0;
 663                 }
 664         }
 665         return extent_writepages(tree, mapping, btree_get_extent, wbc);
 666 }
 667
 668 int btree_readpage(struct file *file, struct page *page)
 669 {
 670         struct extent_io_tree *tree;
 671         tree = &BTRFS_I(page->mapping->host)->io_tree;
 672         return extent_read_full_page(tree, page, btree_get_extent);
 673 }
 674
 675 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
 676 {
 677         struct extent_io_tree *tree;
 678         struct extent_map_tree *map;
 679         int ret;
 680
 681         if (PageWriteback(page) || PageDirty(page))
 682             return 0;
 683
 684         tree = &BTRFS_I(page->mapping->host)->io_tree;
 685         map = &BTRFS_I(page->mapping->host)->extent_tree;
 686
 687         ret = try_release_extent_state(map, tree, page, gfp_flags);
 688         if (!ret) {
 689                 return 0;
 690         }
 691
 692         ret = try_release_extent_buffer(tree, page);
 693         if (ret == 1) {
 694                 ClearPagePrivate(page);
 695                 set_page_private(page, 0);
 696                 page_cache_release(page);
 697         }
 698
 699         return ret;
 700 }
 701
 702 static void btree_invalidatepage(struct page *page, unsigned long offset)
 703 {
 704         struct extent_io_tree *tree;
 705         tree = &BTRFS_I(page->mapping->host)->io_tree;
 706         extent_invalidatepage(tree, page, offset);
 707         btree_releasepage(page, GFP_NOFS);
 708         if (PagePrivate(page)) {
 709                 printk("warning page private not zero on page %Lu\n",
 710                        page_offset(page));
 711                 ClearPagePrivate(page);
 712                 set_page_private(page, 0);
 713                 page_cache_release(page);
 714         }
 715 }
 716
 717 #if 0
 718 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 719 {
 720         struct buffer_head *bh;
 721         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 722         struct buffer_head *head;
 723         if (!page_has_buffers(page)) {
 724                 create_empty_buffers(page, root->fs_info->sb->s_blocksize,
 725                                         (1 << BH_Dirty)|(1 << BH_Uptodate));
 726         }
 727         head = page_buffers(page);
 728         bh = head;
 729         do {
 730                 if (buffer_dirty(bh))
 731                         csum_tree_block(root, bh, 0);
 732                 bh = bh->b_this_page;
 733         } while (bh != head);
 734         return block_write_full_page(page, btree_get_block, wbc);
 735 }
 736 #endif
 737
 738 static struct address_space_operations btree_aops = {
 739         .readpage       = btree_readpage,
 740         .writepage      = btree_writepage,
 741         .writepages     = btree_writepages,
 742         .releasepage    = btree_releasepage,
 743         .invalidatepage = btree_invalidatepage,
 744         .sync_page      = block_sync_page,
 745 };
 746
 747 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
 748                          u64 parent_transid)
 749 {
 750         struct extent_buffer *buf = NULL;
 751         struct inode *btree_inode = root->fs_info->btree_inode;
 752         int ret = 0;
 753
 754         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 755         if (!buf)
 756                 return 0;
 757         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
 758                                  buf, 0, 0, btree_get_extent, 0);
 759         free_extent_buffer(buf);
 760         return ret;
 761 }
 762
 763 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
 764                                             u64 bytenr, u32 blocksize)
 765 {
 766         struct inode *btree_inode = root->fs_info->btree_inode;
 767         struct extent_buffer *eb;
 768         eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 769                                 bytenr, blocksize, GFP_NOFS);
 770         return eb;
 771 }
 772
 773 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 774                                                  u64 bytenr, u32 blocksize)
 775 {
 776         struct inode *btree_inode = root->fs_info->btree_inode;
 777         struct extent_buffer *eb;
 778
 779         eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 780                                  bytenr, blocksize, NULL, GFP_NOFS);
 781         return eb;
 782 }
 783
 784
 785 int btrfs_write_tree_block(struct extent_buffer *buf)
 786 {
 787         return btrfs_fdatawrite_range(buf->first_page->mapping, buf->start,
 788                                       buf->start + buf->len - 1, WB_SYNC_ALL);
 789 }
 790
 791 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
 792 {
 793         return btrfs_wait_on_page_writeback_range(buf->first_page->mapping,
 794                                   buf->start, buf->start + buf->len -1);
 795 }
 796
 797 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 798                                       u32 blocksize, u64 parent_transid)
 799 {
 800         struct extent_buffer *buf = NULL;
 801         struct inode *btree_inode = root->fs_info->btree_inode;
 802         struct extent_io_tree *io_tree;
 803         int ret;
 804
 805         io_tree = &BTRFS_I(btree_inode)->io_tree;
 806
 807         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 808         if (!buf)
 809                 return NULL;
 810
 811         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
 812
 813         if (ret == 0) {
 814                 buf->flags |= EXTENT_UPTODATE;
 815         } else {
 816                 WARN_ON(1);
 817         }
 818         return buf;
 819
 820 }
 821
 822 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 823                      struct extent_buffer *buf)
 824 {
 825         struct inode *btree_inode = root->fs_info->btree_inode;
 826         if (btrfs_header_generation(buf) ==
 827             root->fs_info->running_transaction->transid) {
 828                 WARN_ON(!btrfs_tree_locked(buf));
 829                 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
 830                                           buf);
 831         }
 832         return 0;
 833 }
 834
 835 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
 836                         u32 stripesize, struct btrfs_root *root,
 837                         struct btrfs_fs_info *fs_info,
 838                         u64 objectid)
 839 {
 840         root->node = NULL;
 841         root->commit_root = NULL;
 842         root->ref_tree = NULL;
 843         root->sectorsize = sectorsize;
 844         root->nodesize = nodesize;
 845         root->leafsize = leafsize;
 846         root->stripesize = stripesize;
 847         root->ref_cows = 0;
 848         root->track_dirty = 0;
 849
 850         root->fs_info = fs_info;
 851         root->objectid = objectid;
 852         root->last_trans = 0;
 853         root->highest_inode = 0;
 854         root->last_inode_alloc = 0;
 855         root->name = NULL;
 856         root->in_sysfs = 0;
 857
 858         INIT_LIST_HEAD(&root->dirty_list);
 859         INIT_LIST_HEAD(&root->orphan_list);
 860         INIT_LIST_HEAD(&root->dead_list);
 861         spin_lock_init(&root->node_lock);
 862         spin_lock_init(&root->list_lock);
 863         mutex_init(&root->objectid_mutex);
 864         mutex_init(&root->log_mutex);
 865         extent_io_tree_init(&root->dirty_log_pages,
 866                              fs_info->btree_inode->i_mapping, GFP_NOFS);
 867
 868         btrfs_leaf_ref_tree_init(&root->ref_tree_struct);
 869         root->ref_tree = &root->ref_tree_struct;
 870
 871         memset(&root->root_key, 0, sizeof(root->root_key));
 872         memset(&root->root_item, 0, sizeof(root->root_item));
 873         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
 874         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
 875         root->defrag_trans_start = fs_info->generation;
 876         init_completion(&root->kobj_unregister);
 877         root->defrag_running = 0;
 878         root->defrag_level = 0;
 879         root->root_key.objectid = objectid;
 880         root->anon_super.s_root = NULL;
 881         root->anon_super.s_dev = 0;
 882         INIT_LIST_HEAD(&root->anon_super.s_list);
 883         INIT_LIST_HEAD(&root->anon_super.s_instances);
 884         init_rwsem(&root->anon_super.s_umount);
 885
 886         return 0;
 887 }
 888
 889 static int find_and_setup_root(struct btrfs_root *tree_root,
 890                                struct btrfs_fs_info *fs_info,
 891                                u64 objectid,
 892                                struct btrfs_root *root)
 893 {
 894         int ret;
 895         u32 blocksize;
 896         u64 generation;
 897
 898         __setup_root(tree_root->nodesize, tree_root->leafsize,
 899                      tree_root->sectorsize, tree_root->stripesize,
 900                      root, fs_info, objectid);
 901         ret = btrfs_find_last_root(tree_root, objectid,
 902                                    &root->root_item, &root->root_key);
 903         BUG_ON(ret);
 904
 905         generation = btrfs_root_generation(&root->root_item);
 906         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
 907         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
 908                                      blocksize, generation);
 909         BUG_ON(!root->node);
 910         return 0;
 911 }
 912
 913 int btrfs_free_log_root_tree(struct btrfs_trans_handle *trans,
 914                              struct btrfs_fs_info *fs_info)
 915 {
 916         struct extent_buffer *eb;
 917         struct btrfs_root *log_root_tree = fs_info->log_root_tree;
 918         u64 start = 0;
 919         u64 end = 0;
 920         int ret;
 921
 922         if (!log_root_tree)
 923                 return 0;
 924
 925         while(1) {
 926                 ret = find_first_extent_bit(&log_root_tree->dirty_log_pages,
 927                                     0, &start, &end, EXTENT_DIRTY);
 928                 if (ret)
 929                         break;
 930
 931                 clear_extent_dirty(&log_root_tree->dirty_log_pages,
 932                                    start, end, GFP_NOFS);
 933         }
 934         eb = fs_info->log_root_tree->node;
 935
 936         WARN_ON(btrfs_header_level(eb) != 0);
 937         WARN_ON(btrfs_header_nritems(eb) != 0);
 938
 939         ret = btrfs_free_reserved_extent(fs_info->tree_root,
 940                                 eb->start, eb->len);
 941         BUG_ON(ret);
 942
 943         free_extent_buffer(eb);
 944         kfree(fs_info->log_root_tree);
 945         fs_info->log_root_tree = NULL;
 946         return 0;
 947 }
 948
 949 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
 950                              struct btrfs_fs_info *fs_info)
 951 {
 952         struct btrfs_root *root;
 953         struct btrfs_root *tree_root = fs_info->tree_root;
 954
 955         root = kzalloc(sizeof(*root), GFP_NOFS);
 956         if (!root)
 957                 return -ENOMEM;
 958
 959         __setup_root(tree_root->nodesize, tree_root->leafsize,
 960                      tree_root->sectorsize, tree_root->stripesize,
 961                      root, fs_info, BTRFS_TREE_LOG_OBJECTID);
 962
 963         root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
 964         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
 965         root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
 966         root->ref_cows = 0;
 967
 968         root->node = btrfs_alloc_free_block(trans, root, root->leafsize,
 969                                             0, BTRFS_TREE_LOG_OBJECTID,
 970                                             trans->transid, 0, 0, 0);
 971
 972         btrfs_set_header_nritems(root->node, 0);
 973         btrfs_set_header_level(root->node, 0);
 974         btrfs_set_header_bytenr(root->node, root->node->start);
 975         btrfs_set_header_generation(root->node, trans->transid);
 976         btrfs_set_header_owner(root->node, BTRFS_TREE_LOG_OBJECTID);
 977
 978         write_extent_buffer(root->node, root->fs_info->fsid,
 979                             (unsigned long)btrfs_header_fsid(root->node),
 980                             BTRFS_FSID_SIZE);
 981         btrfs_mark_buffer_dirty(root->node);
 982         btrfs_tree_unlock(root->node);
 983         fs_info->log_root_tree = root;
 984         return 0;
 985 }
 986
 987 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
 988                                                struct btrfs_key *location)
 989 {
 990         struct btrfs_root *root;
 991         struct btrfs_fs_info *fs_info = tree_root->fs_info;
 992         struct btrfs_path *path;
 993         struct extent_buffer *l;
 994         u64 highest_inode;
 995         u64 generation;
 996         u32 blocksize;
 997         int ret = 0;
 998
 999         root = kzalloc(sizeof(*root), GFP_NOFS);
1000         if (!root)
1001                 return ERR_PTR(-ENOMEM);
1002         if (location->offset == (u64)-1) {
1003                 ret = find_and_setup_root(tree_root, fs_info,
1004                                           location->objectid, root);
1005                 if (ret) {
1006                         kfree(root);
1007                         return ERR_PTR(ret);
1008                 }
1009                 goto insert;
1010         }
1011
1012         __setup_root(tree_root->nodesize, tree_root->leafsize,
1013                      tree_root->sectorsize, tree_root->stripesize,
1014                      root, fs_info, location->objectid);
1015
1016         path = btrfs_alloc_path();
1017         BUG_ON(!path);
1018         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
1019         if (ret != 0) {
1020                 if (ret > 0)
1021                         ret = -ENOENT;
1022                 goto out;
1023         }
1024         l = path->nodes[0];
1025         read_extent_buffer(l, &root->root_item,
1026                btrfs_item_ptr_offset(l, path->slots[0]),
1027                sizeof(root->root_item));
1028         memcpy(&root->root_key, location, sizeof(*location));
1029         ret = 0;
1030 out:
1031         btrfs_release_path(root, path);
1032         btrfs_free_path(path);
1033         if (ret) {
1034                 kfree(root);
1035                 return ERR_PTR(ret);
1036         }
1037         generation = btrfs_root_generation(&root->root_item);
1038         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1039         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1040                                      blocksize, generation);
1041         BUG_ON(!root->node);
1042 insert:
1043         if (location->objectid != BTRFS_TREE_LOG_OBJECTID) {
1044                 root->ref_cows = 1;
1045                 ret = btrfs_find_highest_inode(root, &highest_inode);
1046                 if (ret == 0) {
1047                         root->highest_inode = highest_inode;
1048                         root->last_inode_alloc = highest_inode;
1049                 }
1050         }
1051         return root;
1052 }
1053
1054 struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
1055                                         u64 root_objectid)
1056 {
1057         struct btrfs_root *root;
1058
1059         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID)
1060                 return fs_info->tree_root;
1061         if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID)
1062                 return fs_info->extent_root;
1063
1064         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1065                                  (unsigned long)root_objectid);
1066         return root;
1067 }
1068
1069 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
1070                                               struct btrfs_key *location)
1071 {
1072         struct btrfs_root *root;
1073         int ret;
1074
1075         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1076                 return fs_info->tree_root;
1077         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1078                 return fs_info->extent_root;
1079         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1080                 return fs_info->chunk_root;
1081         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1082                 return fs_info->dev_root;
1083
1084         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1085                                  (unsigned long)location->objectid);
1086         if (root)
1087                 return root;
1088
1089         root = btrfs_read_fs_root_no_radix(fs_info->tree_root, location);
1090         if (IS_ERR(root))
1091                 return root;
1092
1093         set_anon_super(&root->anon_super, NULL);
1094
1095         ret = radix_tree_insert(&fs_info->fs_roots_radix,
1096                                 (unsigned long)root->root_key.objectid,
1097                                 root);
1098         if (ret) {
1099                 free_extent_buffer(root->node);
1100                 kfree(root);
1101                 return ERR_PTR(ret);
1102         }
1103         if (!(fs_info->sb->s_flags & MS_RDONLY)) {
1104                 ret = btrfs_find_dead_roots(fs_info->tree_root,
1105                                             root->root_key.objectid, root);
1106                 BUG_ON(ret);
1107                 btrfs_orphan_cleanup(root);
1108         }
1109         return root;
1110 }
1111
1112 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
1113                                       struct btrfs_key *location,
1114                                       const char *name, int namelen)
1115 {
1116         struct btrfs_root *root;
1117         int ret;
1118
1119         root = btrfs_read_fs_root_no_name(fs_info, location);
1120         if (!root)
1121                 return NULL;
1122
1123         if (root->in_sysfs)
1124                 return root;
1125
1126         ret = btrfs_set_root_name(root, name, namelen);
1127         if (ret) {
1128                 free_extent_buffer(root->node);
1129                 kfree(root);
1130                 return ERR_PTR(ret);
1131         }
1132
1133         ret = btrfs_sysfs_add_root(root);
1134         if (ret) {
1135                 free_extent_buffer(root->node);
1136                 kfree(root->name);
1137                 kfree(root);
1138                 return ERR_PTR(ret);
1139         }
1140         root->in_sysfs = 1;
1141         return root;
1142 }
1143 #if 0
1144 static int add_hasher(struct btrfs_fs_info *info, char *type) {
1145         struct btrfs_hasher *hasher;
1146
1147         hasher = kmalloc(sizeof(*hasher), GFP_NOFS);
1148         if (!hasher)
1149                 return -ENOMEM;
1150         hasher->hash_tfm = crypto_alloc_hash(type, 0, CRYPTO_ALG_ASYNC);
1151         if (!hasher->hash_tfm) {
1152                 kfree(hasher);
1153                 return -EINVAL;
1154         }
1155         spin_lock(&info->hash_lock);
1156         list_add(&hasher->list, &info->hashers);
1157         spin_unlock(&info->hash_lock);
1158         return 0;
1159 }
1160 #endif
1161
1162 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1163 {
1164         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1165         int ret = 0;
1166         struct list_head *cur;
1167         struct btrfs_device *device;
1168         struct backing_dev_info *bdi;
1169 #if 0
1170         if ((bdi_bits & (1 << BDI_write_congested)) &&
1171             btrfs_congested_async(info, 0))
1172                 return 1;
1173 #endif
1174         list_for_each(cur, &info->fs_devices->devices) {
1175                 device = list_entry(cur, struct btrfs_device, dev_list);
1176                 if (!device->bdev)
1177                         continue;
1178                 bdi = blk_get_backing_dev_info(device->bdev);
1179                 if (bdi && bdi_congested(bdi, bdi_bits)) {
1180                         ret = 1;
1181                         break;
1182                 }
1183         }
1184         return ret;
1185 }
1186
1187 /*
1188  * this unplugs every device on the box, and it is only used when page
1189  * is null
1190  */
1191 static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1192 {
1193         struct list_head *cur;
1194         struct btrfs_device *device;
1195         struct btrfs_fs_info *info;
1196
1197         info = (struct btrfs_fs_info *)bdi->unplug_io_data;
1198         list_for_each(cur, &info->fs_devices->devices) {
1199                 device = list_entry(cur, struct btrfs_device, dev_list);
1200                 bdi = blk_get_backing_dev_info(device->bdev);
1201                 if (bdi->unplug_io_fn) {
1202                         bdi->unplug_io_fn(bdi, page);
1203                 }
1204         }
1205 }
1206
1207 void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1208 {
1209         struct inode *inode;
1210         struct extent_map_tree *em_tree;
1211         struct extent_map *em;
1212         struct address_space *mapping;
1213         u64 offset;
1214
1215         /* the generic O_DIRECT read code does this */
1216         if (!page) {
1217                 __unplug_io_fn(bdi, page);
1218                 return;
1219         }
1220
1221         /*
1222          * page->mapping may change at any time.  Get a consistent copy
1223          * and use that for everything below
1224          */
1225         smp_mb();
1226         mapping = page->mapping;
1227         if (!mapping)
1228                 return;
1229
1230         inode = mapping->host;
1231
1232         /*
1233          * don't do the expensive searching for a small number of
1234          * devices
1235          */
1236         if (BTRFS_I(inode)->root->fs_info->fs_devices->open_devices <= 2) {
1237                 __unplug_io_fn(bdi, page);
1238                 return;
1239         }
1240
1241         offset = page_offset(page);
1242
1243         em_tree = &BTRFS_I(inode)->extent_tree;
1244         spin_lock(&em_tree->lock);
1245         em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
1246         spin_unlock(&em_tree->lock);
1247         if (!em) {
1248                 __unplug_io_fn(bdi, page);
1249                 return;
1250         }
1251
1252         if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1253                 free_extent_map(em);
1254                 __unplug_io_fn(bdi, page);
1255                 return;
1256         }
1257         offset = offset - em->start;
1258         btrfs_unplug_page(&BTRFS_I(inode)->root->fs_info->mapping_tree,
1259                           em->block_start + offset, page);
1260         free_extent_map(em);
1261 }
1262
1263 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1264 {
1265         bdi_init(bdi);
1266         bdi->ra_pages   = default_backing_dev_info.ra_pages;
1267         bdi->state              = 0;
1268         bdi->capabilities       = default_backing_dev_info.capabilities;
1269         bdi->unplug_io_fn       = btrfs_unplug_io_fn;
1270         bdi->unplug_io_data     = info;
1271         bdi->congested_fn       = btrfs_congested_fn;
1272         bdi->congested_data     = info;
1273         return 0;
1274 }
1275
1276 static int bio_ready_for_csum(struct bio *bio)
1277 {
1278         u64 length = 0;
1279         u64 buf_len = 0;
1280         u64 start = 0;
1281         struct page *page;
1282         struct extent_io_tree *io_tree = NULL;
1283         struct btrfs_fs_info *info = NULL;
1284         struct bio_vec *bvec;
1285         int i;
1286         int ret;
1287
1288         bio_for_each_segment(bvec, bio, i) {
1289                 page = bvec->bv_page;
1290                 if (page->private == EXTENT_PAGE_PRIVATE) {
1291                         length += bvec->bv_len;
1292                         continue;
1293                 }
1294                 if (!page->private) {
1295                         length += bvec->bv_len;
1296                         continue;
1297                 }
1298                 length = bvec->bv_len;
1299                 buf_len = page->private >> 2;
1300                 start = page_offset(page) + bvec->bv_offset;
1301                 io_tree = &BTRFS_I(page->mapping->host)->io_tree;
1302                 info = BTRFS_I(page->mapping->host)->root->fs_info;
1303         }
1304         /* are we fully contained in this bio? */
1305         if (buf_len <= length)
1306                 return 1;
1307
1308         ret = extent_range_uptodate(io_tree, start + length,
1309                                     start + buf_len - 1);
1310         if (ret == 1)
1311                 return ret;
1312         return ret;
1313 }
1314
1315 /*
1316  * called by the kthread helper functions to finally call the bio end_io
1317  * functions.  This is where read checksum verification actually happens
1318  */
1319 static void end_workqueue_fn(struct btrfs_work *work)
1320 {
1321         struct bio *bio;
1322         struct end_io_wq *end_io_wq;
1323         struct btrfs_fs_info *fs_info;
1324         int error;
1325
1326         end_io_wq = container_of(work, struct end_io_wq, work);
1327         bio = end_io_wq->bio;
1328         fs_info = end_io_wq->info;
1329
1330         /* metadata bios are special because the whole tree block must
1331          * be checksummed at once.  This makes sure the entire block is in
1332          * ram and up to date before trying to verify things.  For
1333          * blocksize <= pagesize, it is basically a noop
1334          */
1335         if (end_io_wq->metadata && !bio_ready_for_csum(bio)) {
1336                 btrfs_queue_worker(&fs_info->endio_workers,
1337                                    &end_io_wq->work);
1338                 return;
1339         }
1340         error = end_io_wq->error;
1341         bio->bi_private = end_io_wq->private;
1342         bio->bi_end_io = end_io_wq->end_io;
1343         kfree(end_io_wq);
1344         bio_endio(bio, error);
1345 }
1346
1347 static int cleaner_kthread(void *arg)
1348 {
1349         struct btrfs_root *root = arg;
1350
1351         do {
1352                 smp_mb();
1353                 if (root->fs_info->closing)
1354                         break;
1355
1356                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1357                 mutex_lock(&root->fs_info->cleaner_mutex);
1358                 btrfs_clean_old_snapshots(root);
1359                 mutex_unlock(&root->fs_info->cleaner_mutex);
1360
1361                 if (freezing(current)) {
1362                         refrigerator();
1363                 } else {
1364                         smp_mb();
1365                         if (root->fs_info->closing)
1366                                 break;
1367                         set_current_state(TASK_INTERRUPTIBLE);
1368                         schedule();
1369                         __set_current_state(TASK_RUNNING);
1370                 }
1371         } while (!kthread_should_stop());
1372         return 0;
1373 }
1374
1375 static int transaction_kthread(void *arg)
1376 {
1377         struct btrfs_root *root = arg;
1378         struct btrfs_trans_handle *trans;
1379         struct btrfs_transaction *cur;
1380         unsigned long now;
1381         unsigned long delay;
1382         int ret;
1383
1384         do {
1385                 smp_mb();
1386                 if (root->fs_info->closing)
1387                         break;
1388
1389                 delay = HZ * 30;
1390                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1391                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1392
1393                 if (root->fs_info->total_ref_cache_size > 20 * 1024 * 1024) {
1394                         printk("btrfs: total reference cache size %Lu\n",
1395                                 root->fs_info->total_ref_cache_size);
1396                 }
1397
1398                 mutex_lock(&root->fs_info->trans_mutex);
1399                 cur = root->fs_info->running_transaction;
1400                 if (!cur) {
1401                         mutex_unlock(&root->fs_info->trans_mutex);
1402                         goto sleep;
1403                 }
1404
1405                 now = get_seconds();
1406                 if (now < cur->start_time || now - cur->start_time < 30) {
1407                         mutex_unlock(&root->fs_info->trans_mutex);
1408                         delay = HZ * 5;
1409                         goto sleep;
1410                 }
1411                 mutex_unlock(&root->fs_info->trans_mutex);
1412                 trans = btrfs_start_transaction(root, 1);
1413                 ret = btrfs_commit_transaction(trans, root);
1414 sleep:
1415                 wake_up_process(root->fs_info->cleaner_kthread);
1416                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1417
1418                 if (freezing(current)) {
1419                         refrigerator();
1420                 } else {
1421                         if (root->fs_info->closing)
1422                                 break;
1423                         set_current_state(TASK_INTERRUPTIBLE);
1424                         schedule_timeout(delay);
1425                         __set_current_state(TASK_RUNNING);
1426                 }
1427         } while (!kthread_should_stop());
1428         return 0;
1429 }
1430
1431 struct btrfs_root *open_ctree(struct super_block *sb,
1432                               struct btrfs_fs_devices *fs_devices,
1433                               char *options)
1434 {
1435         u32 sectorsize;
1436         u32 nodesize;
1437         u32 leafsize;
1438         u32 blocksize;
1439         u32 stripesize;
1440         u64 generation;
1441         struct btrfs_key location;
1442         struct buffer_head *bh;
1443         struct btrfs_root *extent_root = kzalloc(sizeof(struct btrfs_root),
1444                                                  GFP_NOFS);
1445         struct btrfs_root *tree_root = kzalloc(sizeof(struct btrfs_root),
1446                                                GFP_NOFS);
1447         struct btrfs_fs_info *fs_info = kzalloc(sizeof(*fs_info),
1448                                                 GFP_NOFS);
1449         struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root),
1450                                                 GFP_NOFS);
1451         struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root),
1452                                               GFP_NOFS);
1453         struct btrfs_root *log_tree_root;
1454
1455         int ret;
1456         int err = -EINVAL;
1457
1458         struct btrfs_super_block *disk_super;
1459
1460         if (!extent_root || !tree_root || !fs_info ||
1461             !chunk_root || !dev_root) {
1462                 err = -ENOMEM;
1463                 goto fail;
1464         }
1465         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
1466         INIT_LIST_HEAD(&fs_info->trans_list);
1467         INIT_LIST_HEAD(&fs_info->dead_roots);
1468         INIT_LIST_HEAD(&fs_info->hashers);
1469         INIT_LIST_HEAD(&fs_info->delalloc_inodes);
1470         spin_lock_init(&fs_info->hash_lock);
1471         spin_lock_init(&fs_info->delalloc_lock);
1472         spin_lock_init(&fs_info->new_trans_lock);
1473         spin_lock_init(&fs_info->ref_cache_lock);
1474
1475         init_completion(&fs_info->kobj_unregister);
1476         fs_info->tree_root = tree_root;
1477         fs_info->extent_root = extent_root;
1478         fs_info->chunk_root = chunk_root;
1479         fs_info->dev_root = dev_root;
1480         fs_info->fs_devices = fs_devices;
1481         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
1482         INIT_LIST_HEAD(&fs_info->space_info);
1483         btrfs_mapping_init(&fs_info->mapping_tree);
1484         atomic_set(&fs_info->nr_async_submits, 0);
1485         atomic_set(&fs_info->async_delalloc_pages, 0);
1486         atomic_set(&fs_info->async_submit_draining, 0);
1487         atomic_set(&fs_info->nr_async_bios, 0);
1488         atomic_set(&fs_info->throttles, 0);
1489         atomic_set(&fs_info->throttle_gen, 0);
1490         fs_info->sb = sb;
1491         fs_info->max_extent = (u64)-1;
1492         fs_info->max_inline = 8192 * 1024;
1493         setup_bdi(fs_info, &fs_info->bdi);
1494         fs_info->btree_inode = new_inode(sb);
1495         fs_info->btree_inode->i_ino = 1;
1496         fs_info->btree_inode->i_nlink = 1;
1497
1498         fs_info->thread_pool_size = min(num_online_cpus() + 2, 8);
1499
1500         INIT_LIST_HEAD(&fs_info->ordered_extents);
1501         spin_lock_init(&fs_info->ordered_extent_lock);
1502
1503         sb->s_blocksize = 4096;
1504         sb->s_blocksize_bits = blksize_bits(4096);
1505
1506         /*
1507          * we set the i_size on the btree inode to the max possible int.
1508          * the real end of the address space is determined by all of
1509          * the devices in the system
1510          */
1511         fs_info->btree_inode->i_size = OFFSET_MAX;
1512         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
1513         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
1514
1515         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
1516                              fs_info->btree_inode->i_mapping,
1517                              GFP_NOFS);
1518         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree,
1519                              GFP_NOFS);
1520
1521         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
1522
1523         spin_lock_init(&fs_info->block_group_cache_lock);
1524         fs_info->block_group_cache_tree.rb_node = NULL;
1525
1526         extent_io_tree_init(&fs_info->pinned_extents,
1527                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1528         extent_io_tree_init(&fs_info->pending_del,
1529                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1530         extent_io_tree_init(&fs_info->extent_ins,
1531                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1532         fs_info->do_barriers = 1;
1533
1534         INIT_LIST_HEAD(&fs_info->dead_reloc_roots);
1535         btrfs_leaf_ref_tree_init(&fs_info->reloc_ref_tree);
1536         btrfs_leaf_ref_tree_init(&fs_info->shared_ref_tree);
1537
1538         BTRFS_I(fs_info->btree_inode)->root = tree_root;
1539         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
1540                sizeof(struct btrfs_key));
1541         insert_inode_hash(fs_info->btree_inode);
1542
1543         mutex_init(&fs_info->trans_mutex);
1544         mutex_init(&fs_info->tree_log_mutex);
1545         mutex_init(&fs_info->drop_mutex);
1546         mutex_init(&fs_info->extent_ins_mutex);
1547         mutex_init(&fs_info->pinned_mutex);
1548         mutex_init(&fs_info->chunk_mutex);
1549         mutex_init(&fs_info->transaction_kthread_mutex);
1550         mutex_init(&fs_info->cleaner_mutex);
1551         mutex_init(&fs_info->volume_mutex);
1552         mutex_init(&fs_info->tree_reloc_mutex);
1553         init_waitqueue_head(&fs_info->transaction_throttle);
1554         init_waitqueue_head(&fs_info->transaction_wait);
1555         init_waitqueue_head(&fs_info->async_submit_wait);
1556         init_waitqueue_head(&fs_info->tree_log_wait);
1557         atomic_set(&fs_info->tree_log_commit, 0);
1558         atomic_set(&fs_info->tree_log_writers, 0);
1559         fs_info->tree_log_transid = 0;
1560
1561 #if 0
1562         ret = add_hasher(fs_info, "crc32c");
1563         if (ret) {
1564                 printk("btrfs: failed hash setup, modprobe cryptomgr?\n");
1565                 err = -ENOMEM;
1566                 goto fail_iput;
1567         }
1568 #endif
1569         __setup_root(4096, 4096, 4096, 4096, tree_root,
1570                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
1571
1572
1573         bh = __bread(fs_devices->latest_bdev,
1574                      BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
1575         if (!bh)
1576                 goto fail_iput;
1577
1578         memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));
1579         brelse(bh);
1580
1581         memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
1582
1583         disk_super = &fs_info->super_copy;
1584         if (!btrfs_super_root(disk_super))
1585                 goto fail_sb_buffer;
1586
1587         ret = btrfs_parse_options(tree_root, options);
1588         if (ret) {
1589                 err = ret;
1590                 goto fail_sb_buffer;
1591         }
1592
1593         /*
1594          * we need to start all the end_io workers up front because the
1595          * queue work function gets called at interrupt time, and so it
1596          * cannot dynamically grow.
1597          */
1598         btrfs_init_workers(&fs_info->workers, "worker",
1599                            fs_info->thread_pool_size);
1600
1601         btrfs_init_workers(&fs_info->delalloc_workers, "delalloc",
1602                            fs_info->thread_pool_size);
1603
1604         btrfs_init_workers(&fs_info->submit_workers, "submit",
1605                            min_t(u64, fs_devices->num_devices,
1606                            fs_info->thread_pool_size));
1607
1608         /* a higher idle thresh on the submit workers makes it much more
1609          * likely that bios will be send down in a sane order to the
1610          * devices
1611          */
1612         fs_info->submit_workers.idle_thresh = 64;
1613
1614         fs_info->workers.idle_thresh = 16;
1615         fs_info->workers.ordered = 1;
1616
1617         fs_info->delalloc_workers.idle_thresh = 2;
1618         fs_info->delalloc_workers.ordered = 1;
1619
1620         btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1);
1621         btrfs_init_workers(&fs_info->endio_workers, "endio",
1622                            fs_info->thread_pool_size);
1623         btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
1624                            fs_info->thread_pool_size);
1625
1626         /*
1627          * endios are largely parallel and should have a very
1628          * low idle thresh
1629          */
1630         fs_info->endio_workers.idle_thresh = 4;
1631         fs_info->endio_write_workers.idle_thresh = 64;
1632
1633         btrfs_start_workers(&fs_info->workers, 1);
1634         btrfs_start_workers(&fs_info->submit_workers, 1);
1635         btrfs_start_workers(&fs_info->delalloc_workers, 1);
1636         btrfs_start_workers(&fs_info->fixup_workers, 1);
1637         btrfs_start_workers(&fs_info->endio_workers, fs_info->thread_pool_size);
1638         btrfs_start_workers(&fs_info->endio_write_workers,
1639                             fs_info->thread_pool_size);
1640
1641         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
1642         fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
1643                                     4 * 1024 * 1024 / PAGE_CACHE_SIZE);
1644
1645         nodesize = btrfs_super_nodesize(disk_super);
1646         leafsize = btrfs_super_leafsize(disk_super);
1647         sectorsize = btrfs_super_sectorsize(disk_super);
1648         stripesize = btrfs_super_stripesize(disk_super);
1649         tree_root->nodesize = nodesize;
1650         tree_root->leafsize = leafsize;
1651         tree_root->sectorsize = sectorsize;
1652         tree_root->stripesize = stripesize;
1653
1654         sb->s_blocksize = sectorsize;
1655         sb->s_blocksize_bits = blksize_bits(sectorsize);
1656
1657         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
1658                     sizeof(disk_super->magic))) {
1659                 printk("btrfs: valid FS not found on %s\n", sb->s_id);
1660                 goto fail_sb_buffer;
1661         }
1662
1663         mutex_lock(&fs_info->chunk_mutex);
1664         ret = btrfs_read_sys_array(tree_root);
1665         mutex_unlock(&fs_info->chunk_mutex);
1666         if (ret) {
1667                 printk("btrfs: failed to read the system array on %s\n",
1668                        sb->s_id);
1669                 goto fail_sys_array;
1670         }
1671
1672         blocksize = btrfs_level_size(tree_root,
1673                                      btrfs_super_chunk_root_level(disk_super));
1674         generation = btrfs_super_chunk_root_generation(disk_super);
1675
1676         __setup_root(nodesize, leafsize, sectorsize, stripesize,
1677                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
1678
1679         chunk_root->node = read_tree_block(chunk_root,
1680                                            btrfs_super_chunk_root(disk_super),
1681                                            blocksize, generation);
1682         BUG_ON(!chunk_root->node);
1683
1684         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
1685                  (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
1686                  BTRFS_UUID_SIZE);
1687
1688         mutex_lock(&fs_info->chunk_mutex);
1689         ret = btrfs_read_chunk_tree(chunk_root);
1690         mutex_unlock(&fs_info->chunk_mutex);
1691         if (ret) {
1692                 printk("btrfs: failed to read chunk tree on %s\n", sb->s_id);
1693                 goto fail_chunk_root;
1694         }
1695
1696         btrfs_close_extra_devices(fs_devices);
1697
1698         blocksize = btrfs_level_size(tree_root,
1699                                      btrfs_super_root_level(disk_super));
1700         generation = btrfs_super_generation(disk_super);
1701
1702         tree_root->node = read_tree_block(tree_root,
1703                                           btrfs_super_root(disk_super),
1704                                           blocksize, generation);
1705         if (!tree_root->node)
1706                 goto fail_chunk_root;
1707
1708
1709         ret = find_and_setup_root(tree_root, fs_info,
1710                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
1711         if (ret)
1712                 goto fail_tree_root;
1713         extent_root->track_dirty = 1;
1714
1715         ret = find_and_setup_root(tree_root, fs_info,
1716                                   BTRFS_DEV_TREE_OBJECTID, dev_root);
1717         dev_root->track_dirty = 1;
1718
1719         if (ret)
1720                 goto fail_extent_root;
1721
1722         btrfs_read_block_groups(extent_root);
1723
1724         fs_info->generation = generation + 1;
1725         fs_info->last_trans_committed = generation;
1726         fs_info->data_alloc_profile = (u64)-1;
1727         fs_info->metadata_alloc_profile = (u64)-1;
1728         fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
1729         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
1730                                                "btrfs-cleaner");
1731         if (!fs_info->cleaner_kthread)
1732                 goto fail_extent_root;
1733
1734         fs_info->transaction_kthread = kthread_run(transaction_kthread,
1735                                                    tree_root,
1736                                                    "btrfs-transaction");
1737         if (!fs_info->transaction_kthread)
1738                 goto fail_cleaner;
1739
1740         if (sb->s_flags & MS_RDONLY)
1741                 goto read_fs_root;
1742
1743         if (btrfs_super_log_root(disk_super) != 0) {
1744                 u32 blocksize;
1745                 u64 bytenr = btrfs_super_log_root(disk_super);
1746
1747                 blocksize =
1748                      btrfs_level_size(tree_root,
1749                                       btrfs_super_log_root_level(disk_super));
1750
1751                 log_tree_root = kzalloc(sizeof(struct btrfs_root),
1752                                                       GFP_NOFS);
1753
1754                 __setup_root(nodesize, leafsize, sectorsize, stripesize,
1755                              log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1756
1757                 log_tree_root->node = read_tree_block(tree_root, bytenr,
1758                                                       blocksize,
1759                                                       generation + 1);
1760                 ret = btrfs_recover_log_trees(log_tree_root);
1761                 BUG_ON(ret);
1762         }
1763
1764         ret = btrfs_cleanup_reloc_trees(tree_root);
1765         BUG_ON(ret);
1766
1767         location.objectid = BTRFS_FS_TREE_OBJECTID;
1768         location.type = BTRFS_ROOT_ITEM_KEY;
1769         location.offset = (u64)-1;
1770
1771 read_fs_root:
1772         fs_info->fs_root = btrfs_read_fs_root_no_name(fs_info, &location);
1773         if (!fs_info->fs_root)
1774                 goto fail_cleaner;
1775         return tree_root;
1776
1777 fail_cleaner:
1778         kthread_stop(fs_info->cleaner_kthread);
1779 fail_extent_root:
1780         free_extent_buffer(extent_root->node);
1781 fail_tree_root:
1782         free_extent_buffer(tree_root->node);
1783 fail_chunk_root:
1784         free_extent_buffer(chunk_root->node);
1785 fail_sys_array:
1786 fail_sb_buffer:
1787         btrfs_stop_workers(&fs_info->fixup_workers);
1788         btrfs_stop_workers(&fs_info->delalloc_workers);
1789         btrfs_stop_workers(&fs_info->workers);
1790         btrfs_stop_workers(&fs_info->endio_workers);
1791         btrfs_stop_workers(&fs_info->endio_write_workers);
1792         btrfs_stop_workers(&fs_info->submit_workers);
1793 fail_iput:
1794         iput(fs_info->btree_inode);
1795 fail:
1796         btrfs_close_devices(fs_info->fs_devices);
1797         btrfs_mapping_tree_free(&fs_info->mapping_tree);
1798
1799         kfree(extent_root);
1800         kfree(tree_root);
1801         bdi_destroy(&fs_info->bdi);
1802         kfree(fs_info);
1803         kfree(chunk_root);
1804         kfree(dev_root);
1805         return ERR_PTR(err);
1806 }
1807
1808 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
1809 {
1810         char b[BDEVNAME_SIZE];
1811
1812         if (uptodate) {
1813                 set_buffer_uptodate(bh);
1814         } else {
1815                 if (!buffer_eopnotsupp(bh) && printk_ratelimit()) {
1816                         printk(KERN_WARNING "lost page write due to "
1817                                         "I/O error on %s\n",
1818                                        bdevname(bh->b_bdev, b));
1819                 }
1820                 /* note, we dont' set_buffer_write_io_error because we have
1821                  * our own ways of dealing with the IO errors
1822                  */
1823                 clear_buffer_uptodate(bh);
1824         }
1825         unlock_buffer(bh);
1826         put_bh(bh);
1827 }
1828
1829 int write_all_supers(struct btrfs_root *root)
1830 {
1831         struct list_head *cur;
1832         struct list_head *head = &root->fs_info->fs_devices->devices;
1833         struct btrfs_device *dev;
1834         struct btrfs_super_block *sb;
1835         struct btrfs_dev_item *dev_item;
1836         struct buffer_head *bh;
1837         int ret;
1838         int do_barriers;
1839         int max_errors;
1840         int total_errors = 0;
1841         u32 crc;
1842         u64 flags;
1843
1844         max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
1845         do_barriers = !btrfs_test_opt(root, NOBARRIER);
1846
1847         sb = &root->fs_info->super_for_commit;
1848         dev_item = &sb->dev_item;
1849         list_for_each(cur, head) {
1850                 dev = list_entry(cur, struct btrfs_device, dev_list);
1851                 if (!dev->bdev) {
1852                         total_errors++;
1853                         continue;
1854                 }
1855                 if (!dev->in_fs_metadata || !dev->writeable)
1856                         continue;
1857
1858                 btrfs_set_stack_device_generation(dev_item, 0);
1859                 btrfs_set_stack_device_type(dev_item, dev->type);
1860                 btrfs_set_stack_device_id(dev_item, dev->devid);
1861                 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
1862                 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
1863                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
1864                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
1865                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
1866                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
1867                 memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
1868                 flags = btrfs_super_flags(sb);
1869                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
1870
1871
1872                 crc = ~(u32)0;
1873                 crc = btrfs_csum_data(root, (char *)sb + BTRFS_CSUM_SIZE, crc,
1874                                       BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
1875                 btrfs_csum_final(crc, sb->csum);
1876
1877                 bh = __getblk(dev->bdev, BTRFS_SUPER_INFO_OFFSET / 4096,
1878                               BTRFS_SUPER_INFO_SIZE);
1879
1880                 memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
1881                 dev->pending_io = bh;
1882
1883                 get_bh(bh);
1884                 set_buffer_uptodate(bh);
1885                 lock_buffer(bh);
1886                 bh->b_end_io = btrfs_end_buffer_write_sync;
1887
1888                 if (do_barriers && dev->barriers) {
1889                         ret = submit_bh(WRITE_BARRIER, bh);
1890                         if (ret == -EOPNOTSUPP) {
1891                                 printk("btrfs: disabling barriers on dev %s\n",
1892                                        dev->name);
1893                                 set_buffer_uptodate(bh);
1894                                 dev->barriers = 0;
1895                                 get_bh(bh);
1896                                 lock_buffer(bh);
1897                                 ret = submit_bh(WRITE, bh);
1898                         }
1899                 } else {
1900                         ret = submit_bh(WRITE, bh);
1901                 }
1902                 if (ret)
1903                         total_errors++;
1904         }
1905         if (total_errors > max_errors) {
1906                 printk("btrfs: %d errors while writing supers\n", total_errors);
1907                 BUG();
1908         }
1909         total_errors = 0;
1910
1911         list_for_each(cur, head) {
1912                 dev = list_entry(cur, struct btrfs_device, dev_list);
1913                 if (!dev->bdev)
1914                         continue;
1915                 if (!dev->in_fs_metadata || !dev->writeable)
1916                         continue;
1917
1918                 BUG_ON(!dev->pending_io);
1919                 bh = dev->pending_io;
1920                 wait_on_buffer(bh);
1921                 if (!buffer_uptodate(dev->pending_io)) {
1922                         if (do_barriers && dev->barriers) {
1923                                 printk("btrfs: disabling barriers on dev %s\n",
1924                                        dev->name);
1925                                 set_buffer_uptodate(bh);
1926                                 get_bh(bh);
1927                                 lock_buffer(bh);
1928                                 dev->barriers = 0;
1929                                 ret = submit_bh(WRITE, bh);
1930                                 BUG_ON(ret);
1931                                 wait_on_buffer(bh);
1932                                 if (!buffer_uptodate(bh))
1933                                         total_errors++;
1934                         } else {
1935                                 total_errors++;
1936                         }
1937
1938                 }
1939                 dev->pending_io = NULL;
1940                 brelse(bh);
1941         }
1942         if (total_errors > max_errors) {
1943                 printk("btrfs: %d errors while writing supers\n", total_errors);
1944                 BUG();
1945         }
1946         return 0;
1947 }
1948
1949 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
1950                       *root)
1951 {
1952         int ret;
1953
1954         ret = write_all_supers(root);
1955         return ret;
1956 }
1957
1958 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
1959 {
1960         radix_tree_delete(&fs_info->fs_roots_radix,
1961                           (unsigned long)root->root_key.objectid);
1962         if (root->anon_super.s_dev) {
1963                 down_write(&root->anon_super.s_umount);
1964                 kill_anon_super(&root->anon_super);
1965         }
1966         if (root->in_sysfs)
1967                 btrfs_sysfs_del_root(root);
1968         if (root->node)
1969                 free_extent_buffer(root->node);
1970         if (root->commit_root)
1971                 free_extent_buffer(root->commit_root);
1972         if (root->name)
1973                 kfree(root->name);
1974         kfree(root);
1975         return 0;
1976 }
1977
1978 static int del_fs_roots(struct btrfs_fs_info *fs_info)
1979 {
1980         int ret;
1981         struct btrfs_root *gang[8];
1982         int i;
1983
1984         while(1) {
1985                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
1986                                              (void **)gang, 0,
1987                                              ARRAY_SIZE(gang));
1988                 if (!ret)
1989                         break;
1990                 for (i = 0; i < ret; i++)
1991                         btrfs_free_fs_root(fs_info, gang[i]);
1992         }
1993         return 0;
1994 }
1995
1996 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
1997 {
1998         u64 root_objectid = 0;
1999         struct btrfs_root *gang[8];
2000         int i;
2001         int ret;
2002
2003         while (1) {
2004                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2005                                              (void **)gang, root_objectid,
2006                                              ARRAY_SIZE(gang));
2007                 if (!ret)
2008                         break;
2009                 for (i = 0; i < ret; i++) {
2010                         root_objectid = gang[i]->root_key.objectid;
2011                         ret = btrfs_find_dead_roots(fs_info->tree_root,
2012                                                     root_objectid, gang[i]);
2013                         BUG_ON(ret);
2014                         btrfs_orphan_cleanup(gang[i]);
2015                 }
2016                 root_objectid++;
2017         }
2018         return 0;
2019 }
2020
2021 int btrfs_commit_super(struct btrfs_root *root)
2022 {
2023         struct btrfs_trans_handle *trans;
2024         int ret;
2025
2026         mutex_lock(&root->fs_info->cleaner_mutex);
2027         btrfs_clean_old_snapshots(root);
2028         mutex_unlock(&root->fs_info->cleaner_mutex);
2029         trans = btrfs_start_transaction(root, 1);
2030         ret = btrfs_commit_transaction(trans, root);
2031         BUG_ON(ret);
2032         /* run commit again to drop the original snapshot */
2033         trans = btrfs_start_transaction(root, 1);
2034         btrfs_commit_transaction(trans, root);
2035         ret = btrfs_write_and_wait_transaction(NULL, root);
2036         BUG_ON(ret);
2037
2038         ret = write_ctree_super(NULL, root);
2039         return ret;
2040 }
2041
2042 int close_ctree(struct btrfs_root *root)
2043 {
2044         struct btrfs_fs_info *fs_info = root->fs_info;
2045         int ret;
2046
2047         fs_info->closing = 1;
2048         smp_mb();
2049
2050         kthread_stop(root->fs_info->transaction_kthread);
2051         kthread_stop(root->fs_info->cleaner_kthread);
2052
2053         if (!(fs_info->sb->s_flags & MS_RDONLY)) {
2054                 ret =  btrfs_commit_super(root);
2055                 if (ret) {
2056                         printk("btrfs: commit super returns %d\n", ret);
2057                 }
2058         }
2059
2060         if (fs_info->delalloc_bytes) {
2061                 printk("btrfs: at unmount delalloc count %Lu\n",
2062                        fs_info->delalloc_bytes);
2063         }
2064         if (fs_info->total_ref_cache_size) {
2065                 printk("btrfs: at umount reference cache size %Lu\n",
2066                         fs_info->total_ref_cache_size);
2067         }
2068
2069         if (fs_info->extent_root->node)
2070                 free_extent_buffer(fs_info->extent_root->node);
2071
2072         if (fs_info->tree_root->node)
2073                 free_extent_buffer(fs_info->tree_root->node);
2074
2075         if (root->fs_info->chunk_root->node);
2076                 free_extent_buffer(root->fs_info->chunk_root->node);
2077
2078         if (root->fs_info->dev_root->node);
2079                 free_extent_buffer(root->fs_info->dev_root->node);
2080
2081         btrfs_free_block_groups(root->fs_info);
2082
2083         del_fs_roots(fs_info);
2084
2085         iput(fs_info->btree_inode);
2086
2087         btrfs_stop_workers(&fs_info->fixup_workers);
2088         btrfs_stop_workers(&fs_info->delalloc_workers);
2089         btrfs_stop_workers(&fs_info->workers);
2090         btrfs_stop_workers(&fs_info->endio_workers);
2091         btrfs_stop_workers(&fs_info->endio_write_workers);
2092         btrfs_stop_workers(&fs_info->submit_workers);
2093
2094 #if 0
2095         while(!list_empty(&fs_info->hashers)) {
2096                 struct btrfs_hasher *hasher;
2097                 hasher = list_entry(fs_info->hashers.next, struct btrfs_hasher,
2098                                     hashers);
2099                 list_del(&hasher->hashers);
2100                 crypto_free_hash(&fs_info->hash_tfm);
2101                 kfree(hasher);
2102         }
2103 #endif
2104         btrfs_close_devices(fs_info->fs_devices);
2105         btrfs_mapping_tree_free(&fs_info->mapping_tree);
2106
2107         bdi_destroy(&fs_info->bdi);
2108
2109         kfree(fs_info->extent_root);
2110         kfree(fs_info->tree_root);
2111         kfree(fs_info->chunk_root);
2112         kfree(fs_info->dev_root);
2113         return 0;
2114 }
2115
2116 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
2117 {
2118         int ret;
2119         struct inode *btree_inode = buf->first_page->mapping->host;
2120
2121         ret = extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf);
2122         if (!ret)
2123                 return ret;
2124
2125         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
2126                                     parent_transid);
2127         return !ret;
2128 }
2129
2130 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
2131 {
2132         struct inode *btree_inode = buf->first_page->mapping->host;
2133         return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
2134                                           buf);
2135 }
2136
2137 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
2138 {
2139         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2140         u64 transid = btrfs_header_generation(buf);
2141         struct inode *btree_inode = root->fs_info->btree_inode;
2142
2143         WARN_ON(!btrfs_tree_locked(buf));
2144         if (transid != root->fs_info->generation) {
2145                 printk(KERN_CRIT "transid mismatch buffer %llu, found %Lu running %Lu\n",
2146                         (unsigned long long)buf->start,
2147                         transid, root->fs_info->generation);
2148                 WARN_ON(1);
2149         }
2150         set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree, buf);
2151 }
2152
2153 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
2154 {
2155         /*
2156          * looks as though older kernels can get into trouble with
2157          * this code, they end up stuck in balance_dirty_pages forever
2158          */
2159         struct extent_io_tree *tree;
2160         u64 num_dirty;
2161         u64 start = 0;
2162         unsigned long thresh = 32 * 1024 * 1024;
2163         tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
2164
2165         if (current_is_pdflush() || current->flags & PF_MEMALLOC)
2166                 return;
2167
2168         num_dirty = count_range_bits(tree, &start, (u64)-1,
2169                                      thresh, EXTENT_DIRTY);
2170         if (num_dirty > thresh) {
2171                 balance_dirty_pages_ratelimited_nr(
2172                                    root->fs_info->btree_inode->i_mapping, 1);
2173         }
2174         return;
2175 }
2176
2177 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
2178 {
2179         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2180         int ret;
2181         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
2182         if (ret == 0) {
2183                 buf->flags |= EXTENT_UPTODATE;
2184         }
2185         return ret;
2186 }
2187
2188 int btree_lock_page_hook(struct page *page)
2189 {
2190         struct inode *inode = page->mapping->host;
2191         struct btrfs_root *root = BTRFS_I(inode)->root;
2192         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2193         struct extent_buffer *eb;
2194         unsigned long len;
2195         u64 bytenr = page_offset(page);
2196
2197         if (page->private == EXTENT_PAGE_PRIVATE)
2198                 goto out;
2199
2200         len = page->private >> 2;
2201         eb = find_extent_buffer(io_tree, bytenr, len, GFP_NOFS);
2202         if (!eb)
2203                 goto out;
2204
2205         btrfs_tree_lock(eb);
2206         spin_lock(&root->fs_info->hash_lock);
2207         btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
2208         spin_unlock(&root->fs_info->hash_lock);
2209         btrfs_tree_unlock(eb);
2210         free_extent_buffer(eb);
2211 out:
2212         lock_page(page);
2213         return 0;
2214 }
2215
2216 static struct extent_io_ops btree_extent_io_ops = {
2217         .write_cache_pages_lock_hook = btree_lock_page_hook,
2218         .readpage_end_io_hook = btree_readpage_end_io_hook,
2219         .submit_bio_hook = btree_submit_bio_hook,
2220         /* note we're sharing with inode.c for the merge bio hook */
2221         .merge_bio_hook = btrfs_merge_bio_hook,
2222 };