linux/fs/btrfs/ordered-data.c
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   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/slab.h>
  20#include <linux/blkdev.h>
  21#include <linux/writeback.h>
  22#include <linux/pagevec.h>
  23#include "ctree.h"
  24#include "transaction.h"
  25#include "btrfs_inode.h"
  26#include "extent_io.h"
  27
  28static struct kmem_cache *btrfs_ordered_extent_cache;
  29
  30static u64 entry_end(struct btrfs_ordered_extent *entry)
  31{
  32        if (entry->file_offset + entry->len < entry->file_offset)
  33                return (u64)-1;
  34        return entry->file_offset + entry->len;
  35}
  36
  37/* returns NULL if the insertion worked, or it returns the node it did find
  38 * in the tree
  39 */
  40static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
  41                                   struct rb_node *node)
  42{
  43        struct rb_node **p = &root->rb_node;
  44        struct rb_node *parent = NULL;
  45        struct btrfs_ordered_extent *entry;
  46
  47        while (*p) {
  48                parent = *p;
  49                entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
  50
  51                if (file_offset < entry->file_offset)
  52                        p = &(*p)->rb_left;
  53                else if (file_offset >= entry_end(entry))
  54                        p = &(*p)->rb_right;
  55                else
  56                        return parent;
  57        }
  58
  59        rb_link_node(node, parent, p);
  60        rb_insert_color(node, root);
  61        return NULL;
  62}
  63
  64static void ordered_data_tree_panic(struct inode *inode, int errno,
  65                                               u64 offset)
  66{
  67        struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
  68        btrfs_panic(fs_info, errno, "Inconsistency in ordered tree at offset "
  69                    "%llu\n", (unsigned long long)offset);
  70}
  71
  72/*
  73 * look for a given offset in the tree, and if it can't be found return the
  74 * first lesser offset
  75 */
  76static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
  77                                     struct rb_node **prev_ret)
  78{
  79        struct rb_node *n = root->rb_node;
  80        struct rb_node *prev = NULL;
  81        struct rb_node *test;
  82        struct btrfs_ordered_extent *entry;
  83        struct btrfs_ordered_extent *prev_entry = NULL;
  84
  85        while (n) {
  86                entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
  87                prev = n;
  88                prev_entry = entry;
  89
  90                if (file_offset < entry->file_offset)
  91                        n = n->rb_left;
  92                else if (file_offset >= entry_end(entry))
  93                        n = n->rb_right;
  94                else
  95                        return n;
  96        }
  97        if (!prev_ret)
  98                return NULL;
  99
 100        while (prev && file_offset >= entry_end(prev_entry)) {
 101                test = rb_next(prev);
 102                if (!test)
 103                        break;
 104                prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 105                                      rb_node);
 106                if (file_offset < entry_end(prev_entry))
 107                        break;
 108
 109                prev = test;
 110        }
 111        if (prev)
 112                prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
 113                                      rb_node);
 114        while (prev && file_offset < entry_end(prev_entry)) {
 115                test = rb_prev(prev);
 116                if (!test)
 117                        break;
 118                prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 119                                      rb_node);
 120                prev = test;
 121        }
 122        *prev_ret = prev;
 123        return NULL;
 124}
 125
 126/*
 127 * helper to check if a given offset is inside a given entry
 128 */
 129static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
 130{
 131        if (file_offset < entry->file_offset ||
 132            entry->file_offset + entry->len <= file_offset)
 133                return 0;
 134        return 1;
 135}
 136
 137static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
 138                          u64 len)
 139{
 140        if (file_offset + len <= entry->file_offset ||
 141            entry->file_offset + entry->len <= file_offset)
 142                return 0;
 143        return 1;
 144}
 145
 146/*
 147 * look find the first ordered struct that has this offset, otherwise
 148 * the first one less than this offset
 149 */
 150static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
 151                                          u64 file_offset)
 152{
 153        struct rb_root *root = &tree->tree;
 154        struct rb_node *prev = NULL;
 155        struct rb_node *ret;
 156        struct btrfs_ordered_extent *entry;
 157
 158        if (tree->last) {
 159                entry = rb_entry(tree->last, struct btrfs_ordered_extent,
 160                                 rb_node);
 161                if (offset_in_entry(entry, file_offset))
 162                        return tree->last;
 163        }
 164        ret = __tree_search(root, file_offset, &prev);
 165        if (!ret)
 166                ret = prev;
 167        if (ret)
 168                tree->last = ret;
 169        return ret;
 170}
 171
 172/* allocate and add a new ordered_extent into the per-inode tree.
 173 * file_offset is the logical offset in the file
 174 *
 175 * start is the disk block number of an extent already reserved in the
 176 * extent allocation tree
 177 *
 178 * len is the length of the extent
 179 *
 180 * The tree is given a single reference on the ordered extent that was
 181 * inserted.
 182 */
 183static int __btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 184                                      u64 start, u64 len, u64 disk_len,
 185                                      int type, int dio, int compress_type)
 186{
 187        struct btrfs_ordered_inode_tree *tree;
 188        struct rb_node *node;
 189        struct btrfs_ordered_extent *entry;
 190
 191        tree = &BTRFS_I(inode)->ordered_tree;
 192        entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
 193        if (!entry)
 194                return -ENOMEM;
 195
 196        entry->file_offset = file_offset;
 197        entry->start = start;
 198        entry->len = len;
 199        entry->disk_len = disk_len;
 200        entry->bytes_left = len;
 201        entry->inode = igrab(inode);
 202        entry->compress_type = compress_type;
 203        if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
 204                set_bit(type, &entry->flags);
 205
 206        if (dio)
 207                set_bit(BTRFS_ORDERED_DIRECT, &entry->flags);
 208
 209        /* one ref for the tree */
 210        atomic_set(&entry->refs, 1);
 211        init_waitqueue_head(&entry->wait);
 212        INIT_LIST_HEAD(&entry->list);
 213        INIT_LIST_HEAD(&entry->root_extent_list);
 214
 215        trace_btrfs_ordered_extent_add(inode, entry);
 216
 217        spin_lock_irq(&tree->lock);
 218        node = tree_insert(&tree->tree, file_offset,
 219                           &entry->rb_node);
 220        if (node)
 221                ordered_data_tree_panic(inode, -EEXIST, file_offset);
 222        spin_unlock_irq(&tree->lock);
 223
 224        spin_lock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
 225        list_add_tail(&entry->root_extent_list,
 226                      &BTRFS_I(inode)->root->fs_info->ordered_extents);
 227        spin_unlock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
 228
 229        return 0;
 230}
 231
 232int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 233                             u64 start, u64 len, u64 disk_len, int type)
 234{
 235        return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 236                                          disk_len, type, 0,
 237                                          BTRFS_COMPRESS_NONE);
 238}
 239
 240int btrfs_add_ordered_extent_dio(struct inode *inode, u64 file_offset,
 241                                 u64 start, u64 len, u64 disk_len, int type)
 242{
 243        return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 244                                          disk_len, type, 1,
 245                                          BTRFS_COMPRESS_NONE);
 246}
 247
 248int btrfs_add_ordered_extent_compress(struct inode *inode, u64 file_offset,
 249                                      u64 start, u64 len, u64 disk_len,
 250                                      int type, int compress_type)
 251{
 252        return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 253                                          disk_len, type, 0,
 254                                          compress_type);
 255}
 256
 257/*
 258 * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 259 * when an ordered extent is finished.  If the list covers more than one
 260 * ordered extent, it is split across multiples.
 261 */
 262void btrfs_add_ordered_sum(struct inode *inode,
 263                           struct btrfs_ordered_extent *entry,
 264                           struct btrfs_ordered_sum *sum)
 265{
 266        struct btrfs_ordered_inode_tree *tree;
 267
 268        tree = &BTRFS_I(inode)->ordered_tree;
 269        spin_lock_irq(&tree->lock);
 270        list_add_tail(&sum->list, &entry->list);
 271        spin_unlock_irq(&tree->lock);
 272}
 273
 274/*
 275 * this is used to account for finished IO across a given range
 276 * of the file.  The IO may span ordered extents.  If
 277 * a given ordered_extent is completely done, 1 is returned, otherwise
 278 * 0.
 279 *
 280 * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 281 * to make sure this function only returns 1 once for a given ordered extent.
 282 *
 283 * file_offset is updated to one byte past the range that is recorded as
 284 * complete.  This allows you to walk forward in the file.
 285 */
 286int btrfs_dec_test_first_ordered_pending(struct inode *inode,
 287                                   struct btrfs_ordered_extent **cached,
 288                                   u64 *file_offset, u64 io_size, int uptodate)
 289{
 290        struct btrfs_ordered_inode_tree *tree;
 291        struct rb_node *node;
 292        struct btrfs_ordered_extent *entry = NULL;
 293        int ret;
 294        unsigned long flags;
 295        u64 dec_end;
 296        u64 dec_start;
 297        u64 to_dec;
 298
 299        tree = &BTRFS_I(inode)->ordered_tree;
 300        spin_lock_irqsave(&tree->lock, flags);
 301        node = tree_search(tree, *file_offset);
 302        if (!node) {
 303                ret = 1;
 304                goto out;
 305        }
 306
 307        entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 308        if (!offset_in_entry(entry, *file_offset)) {
 309                ret = 1;
 310                goto out;
 311        }
 312
 313        dec_start = max(*file_offset, entry->file_offset);
 314        dec_end = min(*file_offset + io_size, entry->file_offset +
 315                      entry->len);
 316        *file_offset = dec_end;
 317        if (dec_start > dec_end) {
 318                printk(KERN_CRIT "bad ordering dec_start %llu end %llu\n",
 319                       (unsigned long long)dec_start,
 320                       (unsigned long long)dec_end);
 321        }
 322        to_dec = dec_end - dec_start;
 323        if (to_dec > entry->bytes_left) {
 324                printk(KERN_CRIT "bad ordered accounting left %llu size %llu\n",
 325                       (unsigned long long)entry->bytes_left,
 326                       (unsigned long long)to_dec);
 327        }
 328        entry->bytes_left -= to_dec;
 329        if (!uptodate)
 330                set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 331
 332        if (entry->bytes_left == 0)
 333                ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 334        else
 335                ret = 1;
 336out:
 337        if (!ret && cached && entry) {
 338                *cached = entry;
 339                atomic_inc(&entry->refs);
 340        }
 341        spin_unlock_irqrestore(&tree->lock, flags);
 342        return ret == 0;
 343}
 344
 345/*
 346 * this is used to account for finished IO across a given range
 347 * of the file.  The IO should not span ordered extents.  If
 348 * a given ordered_extent is completely done, 1 is returned, otherwise
 349 * 0.
 350 *
 351 * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 352 * to make sure this function only returns 1 once for a given ordered extent.
 353 */
 354int btrfs_dec_test_ordered_pending(struct inode *inode,
 355                                   struct btrfs_ordered_extent **cached,
 356                                   u64 file_offset, u64 io_size, int uptodate)
 357{
 358        struct btrfs_ordered_inode_tree *tree;
 359        struct rb_node *node;
 360        struct btrfs_ordered_extent *entry = NULL;
 361        unsigned long flags;
 362        int ret;
 363
 364        tree = &BTRFS_I(inode)->ordered_tree;
 365        spin_lock_irqsave(&tree->lock, flags);
 366        if (cached && *cached) {
 367                entry = *cached;
 368                goto have_entry;
 369        }
 370
 371        node = tree_search(tree, file_offset);
 372        if (!node) {
 373                ret = 1;
 374                goto out;
 375        }
 376
 377        entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 378have_entry:
 379        if (!offset_in_entry(entry, file_offset)) {
 380                ret = 1;
 381                goto out;
 382        }
 383
 384        if (io_size > entry->bytes_left) {
 385                printk(KERN_CRIT "bad ordered accounting left %llu size %llu\n",
 386                       (unsigned long long)entry->bytes_left,
 387                       (unsigned long long)io_size);
 388        }
 389        entry->bytes_left -= io_size;
 390        if (!uptodate)
 391                set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 392
 393        if (entry->bytes_left == 0)
 394                ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 395        else
 396                ret = 1;
 397out:
 398        if (!ret && cached && entry) {
 399                *cached = entry;
 400                atomic_inc(&entry->refs);
 401        }
 402        spin_unlock_irqrestore(&tree->lock, flags);
 403        return ret == 0;
 404}
 405
 406/*
 407 * used to drop a reference on an ordered extent.  This will free
 408 * the extent if the last reference is dropped
 409 */
 410void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 411{
 412        struct list_head *cur;
 413        struct btrfs_ordered_sum *sum;
 414
 415        trace_btrfs_ordered_extent_put(entry->inode, entry);
 416
 417        if (atomic_dec_and_test(&entry->refs)) {
 418                if (entry->inode)
 419                        btrfs_add_delayed_iput(entry->inode);
 420                while (!list_empty(&entry->list)) {
 421                        cur = entry->list.next;
 422                        sum = list_entry(cur, struct btrfs_ordered_sum, list);
 423                        list_del(&sum->list);
 424                        kfree(sum);
 425                }
 426                kmem_cache_free(btrfs_ordered_extent_cache, entry);
 427        }
 428}
 429
 430/*
 431 * remove an ordered extent from the tree.  No references are dropped
 432 * and waiters are woken up.
 433 */
 434void btrfs_remove_ordered_extent(struct inode *inode,
 435                                 struct btrfs_ordered_extent *entry)
 436{
 437        struct btrfs_ordered_inode_tree *tree;
 438        struct btrfs_root *root = BTRFS_I(inode)->root;
 439        struct rb_node *node;
 440
 441        tree = &BTRFS_I(inode)->ordered_tree;
 442        spin_lock_irq(&tree->lock);
 443        node = &entry->rb_node;
 444        rb_erase(node, &tree->tree);
 445        tree->last = NULL;
 446        set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 447        spin_unlock_irq(&tree->lock);
 448
 449        spin_lock(&root->fs_info->ordered_extent_lock);
 450        list_del_init(&entry->root_extent_list);
 451
 452        trace_btrfs_ordered_extent_remove(inode, entry);
 453
 454        /*
 455         * we have no more ordered extents for this inode and
 456         * no dirty pages.  We can safely remove it from the
 457         * list of ordered extents
 458         */
 459        if (RB_EMPTY_ROOT(&tree->tree) &&
 460            !mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) {
 461                list_del_init(&BTRFS_I(inode)->ordered_operations);
 462        }
 463        spin_unlock(&root->fs_info->ordered_extent_lock);
 464        wake_up(&entry->wait);
 465}
 466
 467/*
 468 * wait for all the ordered extents in a root.  This is done when balancing
 469 * space between drives.
 470 */
 471void btrfs_wait_ordered_extents(struct btrfs_root *root, int delay_iput)
 472{
 473        struct list_head splice;
 474        struct list_head *cur;
 475        struct btrfs_ordered_extent *ordered;
 476        struct inode *inode;
 477
 478        INIT_LIST_HEAD(&splice);
 479
 480        spin_lock(&root->fs_info->ordered_extent_lock);
 481        list_splice_init(&root->fs_info->ordered_extents, &splice);
 482        while (!list_empty(&splice)) {
 483                cur = splice.next;
 484                ordered = list_entry(cur, struct btrfs_ordered_extent,
 485                                     root_extent_list);
 486                list_del_init(&ordered->root_extent_list);
 487                atomic_inc(&ordered->refs);
 488
 489                /*
 490                 * the inode may be getting freed (in sys_unlink path).
 491                 */
 492                inode = igrab(ordered->inode);
 493
 494                spin_unlock(&root->fs_info->ordered_extent_lock);
 495
 496                if (inode) {
 497                        btrfs_start_ordered_extent(inode, ordered, 1);
 498                        btrfs_put_ordered_extent(ordered);
 499                        if (delay_iput)
 500                                btrfs_add_delayed_iput(inode);
 501                        else
 502                                iput(inode);
 503                } else {
 504                        btrfs_put_ordered_extent(ordered);
 505                }
 506
 507                spin_lock(&root->fs_info->ordered_extent_lock);
 508        }
 509        spin_unlock(&root->fs_info->ordered_extent_lock);
 510}
 511
 512/*
 513 * this is used during transaction commit to write all the inodes
 514 * added to the ordered operation list.  These files must be fully on
 515 * disk before the transaction commits.
 516 *
 517 * we have two modes here, one is to just start the IO via filemap_flush
 518 * and the other is to wait for all the io.  When we wait, we have an
 519 * extra check to make sure the ordered operation list really is empty
 520 * before we return
 521 */
 522void btrfs_run_ordered_operations(struct btrfs_root *root, int wait)
 523{
 524        struct btrfs_inode *btrfs_inode;
 525        struct inode *inode;
 526        struct list_head splice;
 527
 528        INIT_LIST_HEAD(&splice);
 529
 530        mutex_lock(&root->fs_info->ordered_operations_mutex);
 531        spin_lock(&root->fs_info->ordered_extent_lock);
 532again:
 533        list_splice_init(&root->fs_info->ordered_operations, &splice);
 534
 535        while (!list_empty(&splice)) {
 536                btrfs_inode = list_entry(splice.next, struct btrfs_inode,
 537                                   ordered_operations);
 538
 539                inode = &btrfs_inode->vfs_inode;
 540
 541                list_del_init(&btrfs_inode->ordered_operations);
 542
 543                /*
 544                 * the inode may be getting freed (in sys_unlink path).
 545                 */
 546                inode = igrab(inode);
 547
 548                if (!wait && inode) {
 549                        list_add_tail(&BTRFS_I(inode)->ordered_operations,
 550                              &root->fs_info->ordered_operations);
 551                }
 552                spin_unlock(&root->fs_info->ordered_extent_lock);
 553
 554                if (inode) {
 555                        if (wait)
 556                                btrfs_wait_ordered_range(inode, 0, (u64)-1);
 557                        else
 558                                filemap_flush(inode->i_mapping);
 559                        btrfs_add_delayed_iput(inode);
 560                }
 561
 562                cond_resched();
 563                spin_lock(&root->fs_info->ordered_extent_lock);
 564        }
 565        if (wait && !list_empty(&root->fs_info->ordered_operations))
 566                goto again;
 567
 568        spin_unlock(&root->fs_info->ordered_extent_lock);
 569        mutex_unlock(&root->fs_info->ordered_operations_mutex);
 570}
 571
 572/*
 573 * Used to start IO or wait for a given ordered extent to finish.
 574 *
 575 * If wait is one, this effectively waits on page writeback for all the pages
 576 * in the extent, and it waits on the io completion code to insert
 577 * metadata into the btree corresponding to the extent
 578 */
 579void btrfs_start_ordered_extent(struct inode *inode,
 580                                       struct btrfs_ordered_extent *entry,
 581                                       int wait)
 582{
 583        u64 start = entry->file_offset;
 584        u64 end = start + entry->len - 1;
 585
 586        trace_btrfs_ordered_extent_start(inode, entry);
 587
 588        /*
 589         * pages in the range can be dirty, clean or writeback.  We
 590         * start IO on any dirty ones so the wait doesn't stall waiting
 591         * for the flusher thread to find them
 592         */
 593        if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 594                filemap_fdatawrite_range(inode->i_mapping, start, end);
 595        if (wait) {
 596                wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
 597                                                 &entry->flags));
 598        }
 599}
 600
 601/*
 602 * Used to wait on ordered extents across a large range of bytes.
 603 */
 604void btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 605{
 606        u64 end;
 607        u64 orig_end;
 608        struct btrfs_ordered_extent *ordered;
 609        int found;
 610
 611        if (start + len < start) {
 612                orig_end = INT_LIMIT(loff_t);
 613        } else {
 614                orig_end = start + len - 1;
 615                if (orig_end > INT_LIMIT(loff_t))
 616                        orig_end = INT_LIMIT(loff_t);
 617        }
 618
 619        /* start IO across the range first to instantiate any delalloc
 620         * extents
 621         */
 622        filemap_fdatawrite_range(inode->i_mapping, start, orig_end);
 623
 624        /*
 625         * So with compression we will find and lock a dirty page and clear the
 626         * first one as dirty, setup an async extent, and immediately return
 627         * with the entire range locked but with nobody actually marked with
 628         * writeback.  So we can't just filemap_write_and_wait_range() and
 629         * expect it to work since it will just kick off a thread to do the
 630         * actual work.  So we need to call filemap_fdatawrite_range _again_
 631         * since it will wait on the page lock, which won't be unlocked until
 632         * after the pages have been marked as writeback and so we're good to go
 633         * from there.  We have to do this otherwise we'll miss the ordered
 634         * extents and that results in badness.  Please Josef, do not think you
 635         * know better and pull this out at some point in the future, it is
 636         * right and you are wrong.
 637         */
 638        if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
 639                     &BTRFS_I(inode)->runtime_flags))
 640                filemap_fdatawrite_range(inode->i_mapping, start, orig_end);
 641
 642        filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 643
 644        end = orig_end;
 645        found = 0;
 646        while (1) {
 647                ordered = btrfs_lookup_first_ordered_extent(inode, end);
 648                if (!ordered)
 649                        break;
 650                if (ordered->file_offset > orig_end) {
 651                        btrfs_put_ordered_extent(ordered);
 652                        break;
 653                }
 654                if (ordered->file_offset + ordered->len < start) {
 655                        btrfs_put_ordered_extent(ordered);
 656                        break;
 657                }
 658                found++;
 659                btrfs_start_ordered_extent(inode, ordered, 1);
 660                end = ordered->file_offset;
 661                btrfs_put_ordered_extent(ordered);
 662                if (end == 0 || end == start)
 663                        break;
 664                end--;
 665        }
 666}
 667
 668/*
 669 * find an ordered extent corresponding to file_offset.  return NULL if
 670 * nothing is found, otherwise take a reference on the extent and return it
 671 */
 672struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
 673                                                         u64 file_offset)
 674{
 675        struct btrfs_ordered_inode_tree *tree;
 676        struct rb_node *node;
 677        struct btrfs_ordered_extent *entry = NULL;
 678
 679        tree = &BTRFS_I(inode)->ordered_tree;
 680        spin_lock_irq(&tree->lock);
 681        node = tree_search(tree, file_offset);
 682        if (!node)
 683                goto out;
 684
 685        entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 686        if (!offset_in_entry(entry, file_offset))
 687                entry = NULL;
 688        if (entry)
 689                atomic_inc(&entry->refs);
 690out:
 691        spin_unlock_irq(&tree->lock);
 692        return entry;
 693}
 694
 695/* Since the DIO code tries to lock a wide area we need to look for any ordered
 696 * extents that exist in the range, rather than just the start of the range.
 697 */
 698struct btrfs_ordered_extent *btrfs_lookup_ordered_range(struct inode *inode,
 699                                                        u64 file_offset,
 700                                                        u64 len)
 701{
 702        struct btrfs_ordered_inode_tree *tree;
 703        struct rb_node *node;
 704        struct btrfs_ordered_extent *entry = NULL;
 705
 706        tree = &BTRFS_I(inode)->ordered_tree;
 707        spin_lock_irq(&tree->lock);
 708        node = tree_search(tree, file_offset);
 709        if (!node) {
 710                node = tree_search(tree, file_offset + len);
 711                if (!node)
 712                        goto out;
 713        }
 714
 715        while (1) {
 716                entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 717                if (range_overlaps(entry, file_offset, len))
 718                        break;
 719
 720                if (entry->file_offset >= file_offset + len) {
 721                        entry = NULL;
 722                        break;
 723                }
 724                entry = NULL;
 725                node = rb_next(node);
 726                if (!node)
 727                        break;
 728        }
 729out:
 730        if (entry)
 731                atomic_inc(&entry->refs);
 732        spin_unlock_irq(&tree->lock);
 733        return entry;
 734}
 735
 736/*
 737 * lookup and return any extent before 'file_offset'.  NULL is returned
 738 * if none is found
 739 */
 740struct btrfs_ordered_extent *
 741btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
 742{
 743        struct btrfs_ordered_inode_tree *tree;
 744        struct rb_node *node;
 745        struct btrfs_ordered_extent *entry = NULL;
 746
 747        tree = &BTRFS_I(inode)->ordered_tree;
 748        spin_lock_irq(&tree->lock);
 749        node = tree_search(tree, file_offset);
 750        if (!node)
 751                goto out;
 752
 753        entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 754        atomic_inc(&entry->refs);
 755out:
 756        spin_unlock_irq(&tree->lock);
 757        return entry;
 758}
 759
 760/*
 761 * After an extent is done, call this to conditionally update the on disk
 762 * i_size.  i_size is updated to cover any fully written part of the file.
 763 */
 764int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
 765                                struct btrfs_ordered_extent *ordered)
 766{
 767        struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 768        u64 disk_i_size;
 769        u64 new_i_size;
 770        u64 i_size = i_size_read(inode);
 771        struct rb_node *node;
 772        struct rb_node *prev = NULL;
 773        struct btrfs_ordered_extent *test;
 774        int ret = 1;
 775
 776        if (ordered)
 777                offset = entry_end(ordered);
 778        else
 779                offset = ALIGN(offset, BTRFS_I(inode)->root->sectorsize);
 780
 781        spin_lock_irq(&tree->lock);
 782        disk_i_size = BTRFS_I(inode)->disk_i_size;
 783
 784        /* truncate file */
 785        if (disk_i_size > i_size) {
 786                BTRFS_I(inode)->disk_i_size = i_size;
 787                ret = 0;
 788                goto out;
 789        }
 790
 791        /*
 792         * if the disk i_size is already at the inode->i_size, or
 793         * this ordered extent is inside the disk i_size, we're done
 794         */
 795        if (disk_i_size == i_size || offset <= disk_i_size) {
 796                goto out;
 797        }
 798
 799        /*
 800         * walk backward from this ordered extent to disk_i_size.
 801         * if we find an ordered extent then we can't update disk i_size
 802         * yet
 803         */
 804        if (ordered) {
 805                node = rb_prev(&ordered->rb_node);
 806        } else {
 807                prev = tree_search(tree, offset);
 808                /*
 809                 * we insert file extents without involving ordered struct,
 810                 * so there should be no ordered struct cover this offset
 811                 */
 812                if (prev) {
 813                        test = rb_entry(prev, struct btrfs_ordered_extent,
 814                                        rb_node);
 815                        BUG_ON(offset_in_entry(test, offset));
 816                }
 817                node = prev;
 818        }
 819        for (; node; node = rb_prev(node)) {
 820                test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 821
 822                /* We treat this entry as if it doesnt exist */
 823                if (test_bit(BTRFS_ORDERED_UPDATED_ISIZE, &test->flags))
 824                        continue;
 825                if (test->file_offset + test->len <= disk_i_size)
 826                        break;
 827                if (test->file_offset >= i_size)
 828                        break;
 829                if (test->file_offset >= disk_i_size) {
 830                        /*
 831                         * we don't update disk_i_size now, so record this
 832                         * undealt i_size. Or we will not know the real
 833                         * i_size.
 834                         */
 835                        if (test->outstanding_isize < offset)
 836                                test->outstanding_isize = offset;
 837                        if (ordered &&
 838                            ordered->outstanding_isize >
 839                            test->outstanding_isize)
 840                                test->outstanding_isize =
 841                                                ordered->outstanding_isize;
 842                        goto out;
 843                }
 844        }
 845        new_i_size = min_t(u64, offset, i_size);
 846
 847        /*
 848         * Some ordered extents may completed before the current one, and
 849         * we hold the real i_size in ->outstanding_isize.
 850         */
 851        if (ordered && ordered->outstanding_isize > new_i_size)
 852                new_i_size = min_t(u64, ordered->outstanding_isize, i_size);
 853        BTRFS_I(inode)->disk_i_size = new_i_size;
 854        ret = 0;
 855out:
 856        /*
 857         * We need to do this because we can't remove ordered extents until
 858         * after the i_disk_size has been updated and then the inode has been
 859         * updated to reflect the change, so we need to tell anybody who finds
 860         * this ordered extent that we've already done all the real work, we
 861         * just haven't completed all the other work.
 862         */
 863        if (ordered)
 864                set_bit(BTRFS_ORDERED_UPDATED_ISIZE, &ordered->flags);
 865        spin_unlock_irq(&tree->lock);
 866        return ret;
 867}
 868
 869/*
 870 * search the ordered extents for one corresponding to 'offset' and
 871 * try to find a checksum.  This is used because we allow pages to
 872 * be reclaimed before their checksum is actually put into the btree
 873 */
 874int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
 875                           u32 *sum)
 876{
 877        struct btrfs_ordered_sum *ordered_sum;
 878        struct btrfs_sector_sum *sector_sums;
 879        struct btrfs_ordered_extent *ordered;
 880        struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 881        unsigned long num_sectors;
 882        unsigned long i;
 883        u32 sectorsize = BTRFS_I(inode)->root->sectorsize;
 884        int ret = 1;
 885
 886        ordered = btrfs_lookup_ordered_extent(inode, offset);
 887        if (!ordered)
 888                return 1;
 889
 890        spin_lock_irq(&tree->lock);
 891        list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
 892                if (disk_bytenr >= ordered_sum->bytenr) {
 893                        num_sectors = ordered_sum->len / sectorsize;
 894                        sector_sums = ordered_sum->sums;
 895                        for (i = 0; i < num_sectors; i++) {
 896                                if (sector_sums[i].bytenr == disk_bytenr) {
 897                                        *sum = sector_sums[i].sum;
 898                                        ret = 0;
 899                                        goto out;
 900                                }
 901                        }
 902                }
 903        }
 904out:
 905        spin_unlock_irq(&tree->lock);
 906        btrfs_put_ordered_extent(ordered);
 907        return ret;
 908}
 909
 910
 911/*
 912 * add a given inode to the list of inodes that must be fully on
 913 * disk before a transaction commit finishes.
 914 *
 915 * This basically gives us the ext3 style data=ordered mode, and it is mostly
 916 * used to make sure renamed files are fully on disk.
 917 *
 918 * It is a noop if the inode is already fully on disk.
 919 *
 920 * If trans is not null, we'll do a friendly check for a transaction that
 921 * is already flushing things and force the IO down ourselves.
 922 */
 923void btrfs_add_ordered_operation(struct btrfs_trans_handle *trans,
 924                                 struct btrfs_root *root, struct inode *inode)
 925{
 926        u64 last_mod;
 927
 928        last_mod = max(BTRFS_I(inode)->generation, BTRFS_I(inode)->last_trans);
 929
 930        /*
 931         * if this file hasn't been changed since the last transaction
 932         * commit, we can safely return without doing anything
 933         */
 934        if (last_mod < root->fs_info->last_trans_committed)
 935                return;
 936
 937        /*
 938         * the transaction is already committing.  Just start the IO and
 939         * don't bother with all of this list nonsense
 940         */
 941        if (trans && root->fs_info->running_transaction->blocked) {
 942                btrfs_wait_ordered_range(inode, 0, (u64)-1);
 943                return;
 944        }
 945
 946        spin_lock(&root->fs_info->ordered_extent_lock);
 947        if (list_empty(&BTRFS_I(inode)->ordered_operations)) {
 948                list_add_tail(&BTRFS_I(inode)->ordered_operations,
 949                              &root->fs_info->ordered_operations);
 950        }
 951        spin_unlock(&root->fs_info->ordered_extent_lock);
 952}
 953
 954int __init ordered_data_init(void)
 955{
 956        btrfs_ordered_extent_cache = kmem_cache_create("btrfs_ordered_extent",
 957                                     sizeof(struct btrfs_ordered_extent), 0,
 958                                     SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
 959                                     NULL);
 960        if (!btrfs_ordered_extent_cache)
 961                return -ENOMEM;
 962        return 0;
 963}
 964
 965void ordered_data_exit(void)
 966{
 967        if (btrfs_ordered_extent_cache)
 968                kmem_cache_destroy(btrfs_ordered_extent_cache);
 969}
 970
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