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