fs/ext4/fast_commit.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 /*
   4  * fs/ext4/fast_commit.c
   5  *
   6  * Written by Harshad Shirwadkar <harshadshirwadkar@gmail.com>
   7  *
   8  * Ext4 fast commits routines.
   9  */
  10 #include "ext4.h"
  11 #include "ext4_jbd2.h"
  12 #include "ext4_extents.h"
  13 #include "mballoc.h"
  14
  15 /*
  16  * Ext4 Fast Commits
  17  * -----------------
  18  *
  19  * Ext4 fast commits implement fine grained journalling for Ext4.
  20  *
  21  * Fast commits are organized as a log of tag-length-value (TLV) structs. (See
  22  * struct ext4_fc_tl). Each TLV contains some delta that is replayed TLV by
  23  * TLV during the recovery phase. For the scenarios for which we currently
  24  * don't have replay code, fast commit falls back to full commits.
  25  * Fast commits record delta in one of the following three categories.
  26  *
  27  * (A) Directory entry updates:
  28  *
  29  * - EXT4_FC_TAG_UNLINK         - records directory entry unlink
  30  * - EXT4_FC_TAG_LINK           - records directory entry link
  31  * - EXT4_FC_TAG_CREAT          - records inode and directory entry creation
  32  *
  33  * (B) File specific data range updates:
  34  *
  35  * - EXT4_FC_TAG_ADD_RANGE      - records addition of new blocks to an inode
  36  * - EXT4_FC_TAG_DEL_RANGE      - records deletion of blocks from an inode
  37  *
  38  * (C) Inode metadata (mtime / ctime etc):
  39  *
  40  * - EXT4_FC_TAG_INODE          - record the inode that should be replayed
  41  *                                during recovery. Note that iblocks field is
  42  *                                not replayed and instead derived during
  43  *                                replay.
  44  * Commit Operation
  45  * ----------------
  46  * With fast commits, we maintain all the directory entry operations in the
  47  * order in which they are issued in an in-memory queue. This queue is flushed
  48  * to disk during the commit operation. We also maintain a list of inodes
  49  * that need to be committed during a fast commit in another in memory queue of
  50  * inodes. During the commit operation, we commit in the following order:
  51  *
  52  * [1] Lock inodes for any further data updates by setting COMMITTING state
  53  * [2] Submit data buffers of all the inodes
  54  * [3] Wait for [2] to complete
  55  * [4] Commit all the directory entry updates in the fast commit space
  56  * [5] Commit all the changed inode structures
  57  * [6] Write tail tag (this tag ensures the atomicity, please read the following
  58  *     section for more details).
  59  * [7] Wait for [4], [5] and [6] to complete.
  60  *
  61  * All the inode updates must call ext4_fc_start_update() before starting an
  62  * update. If such an ongoing update is present, fast commit waits for it to
  63  * complete. The completion of such an update is marked by
  64  * ext4_fc_stop_update().
  65  *
  66  * Fast Commit Ineligibility
  67  * -------------------------
  68  *
  69  * Not all operations are supported by fast commits today (e.g extended
  70  * attributes). Fast commit ineligibility is marked by calling
  71  * ext4_fc_mark_ineligible(): This makes next fast commit operation to fall back
  72  * to full commit.
  73  *
  74  * Atomicity of commits
  75  * --------------------
  76  * In order to guarantee atomicity during the commit operation, fast commit
  77  * uses "EXT4_FC_TAG_TAIL" tag that marks a fast commit as complete. Tail
  78  * tag contains CRC of the contents and TID of the transaction after which
  79  * this fast commit should be applied. Recovery code replays fast commit
  80  * logs only if there's at least 1 valid tail present. For every fast commit
  81  * operation, there is 1 tail. This means, we may end up with multiple tails
  82  * in the fast commit space. Here's an example:
  83  *
  84  * - Create a new file A and remove existing file B
  85  * - fsync()
  86  * - Append contents to file A
  87  * - Truncate file A
  88  * - fsync()
  89  *
  90  * The fast commit space at the end of above operations would look like this:
  91  *      [HEAD] [CREAT A] [UNLINK B] [TAIL] [ADD_RANGE A] [DEL_RANGE A] [TAIL]
  92  *             |<---  Fast Commit 1   --->|<---      Fast Commit 2     ---->|
  93  *
  94  * Replay code should thus check for all the valid tails in the FC area.
  95  *
  96  * Fast Commit Replay Idempotence
  97  * ------------------------------
  98  *
  99  * Fast commits tags are idempotent in nature provided the recovery code follows
 100  * certain rules. The guiding principle that the commit path follows while
 101  * committing is that it stores the result of a particular operation instead of
 102  * storing the procedure.
 103  *
 104  * Let's consider this rename operation: 'mv /a /b'. Let's assume dirent '/a'
 105  * was associated with inode 10. During fast commit, instead of storing this
 106  * operation as a procedure "rename a to b", we store the resulting file system
 107  * state as a "series" of outcomes:
 108  *
 109  * - Link dirent b to inode 10
 110  * - Unlink dirent a
 111  * - Inode <10> with valid refcount
 112  *
 113  * Now when recovery code runs, it needs "enforce" this state on the file
 114  * system. This is what guarantees idempotence of fast commit replay.
 115  *
 116  * Let's take an example of a procedure that is not idempotent and see how fast
 117  * commits make it idempotent. Consider following sequence of operations:
 118  *
 119  *     rm A;    mv B A;    read A
 120  *  (x)     (y)        (z)
 121  *
 122  * (x), (y) and (z) are the points at which we can crash. If we store this
 123  * sequence of operations as is then the replay is not idempotent. Let's say
 124  * while in replay, we crash at (z). During the second replay, file A (which was
 125  * actually created as a result of "mv B A" operation) would get deleted. Thus,
 126  * file named A would be absent when we try to read A. So, this sequence of
 127  * operations is not idempotent. However, as mentioned above, instead of storing
 128  * the procedure fast commits store the outcome of each procedure. Thus the fast
 129  * commit log for above procedure would be as follows:
 130  *
 131  * (Let's assume dirent A was linked to inode 10 and dirent B was linked to
 132  * inode 11 before the replay)
 133  *
 134  *    [Unlink A]   [Link A to inode 11]   [Unlink B]   [Inode 11]
 135  * (w)          (x)                    (y)          (z)
 136  *
 137  * If we crash at (z), we will have file A linked to inode 11. During the second
 138  * replay, we will remove file A (inode 11). But we will create it back and make
 139  * it point to inode 11. We won't find B, so we'll just skip that step. At this
 140  * point, the refcount for inode 11 is not reliable, but that gets fixed by the
 141  * replay of last inode 11 tag. Crashes at points (w), (x) and (y) get handled
 142  * similarly. Thus, by converting a non-idempotent procedure into a series of
 143  * idempotent outcomes, fast commits ensured idempotence during the replay.
 144  *
 145  * TODOs
 146  * -----
 147  *
 148  * 0) Fast commit replay path hardening: Fast commit replay code should use
 149  *    journal handles to make sure all the updates it does during the replay
 150  *    path are atomic. With that if we crash during fast commit replay, after
 151  *    trying to do recovery again, we will find a file system where fast commit
 152  *    area is invalid (because new full commit would be found). In order to deal
 153  *    with that, fast commit replay code should ensure that the "FC_REPLAY"
 154  *    superblock state is persisted before starting the replay, so that after
 155  *    the crash, fast commit recovery code can look at that flag and perform
 156  *    fast commit recovery even if that area is invalidated by later full
 157  *    commits.
 158  *
 159  * 1) Fast commit's commit path locks the entire file system during fast
 160  *    commit. This has significant performance penalty. Instead of that, we
 161  *    should use ext4_fc_start/stop_update functions to start inode level
 162  *    updates from ext4_journal_start/stop. Once we do that we can drop file
 163  *    system locking during commit path.
 164  *
 165  * 2) Handle more ineligible cases.
 166  */
 167
 168 #include <trace/events/ext4.h>
 169 static struct kmem_cache *ext4_fc_dentry_cachep;
 170
 171 static void ext4_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
 172 {
 173         BUFFER_TRACE(bh, "");
 174         if (uptodate) {
 175                 ext4_debug("%s: Block %lld up-to-date",
 176                            __func__, bh->b_blocknr);
 177                 set_buffer_uptodate(bh);
 178         } else {
 179                 ext4_debug("%s: Block %lld not up-to-date",
 180                            __func__, bh->b_blocknr);
 181                 clear_buffer_uptodate(bh);
 182         }
 183
 184         unlock_buffer(bh);
 185 }
 186
 187 static inline void ext4_fc_reset_inode(struct inode *inode)
 188 {
 189         struct ext4_inode_info *ei = EXT4_I(inode);
 190
 191         ei->i_fc_lblk_start = 0;
 192         ei->i_fc_lblk_len = 0;
 193 }
 194
 195 void ext4_fc_init_inode(struct inode *inode)
 196 {
 197         struct ext4_inode_info *ei = EXT4_I(inode);
 198
 199         ext4_fc_reset_inode(inode);
 200         ext4_clear_inode_state(inode, EXT4_STATE_FC_COMMITTING);
 201         INIT_LIST_HEAD(&ei->i_fc_list);
 202         INIT_LIST_HEAD(&ei->i_fc_dilist);
 203         init_waitqueue_head(&ei->i_fc_wait);
 204         atomic_set(&ei->i_fc_updates, 0);
 205 }
 206
 207 /* This function must be called with sbi->s_fc_lock held. */
 208 static void ext4_fc_wait_committing_inode(struct inode *inode)
 209 __releases(&EXT4_SB(inode->i_sb)->s_fc_lock)
 210 {
 211         wait_queue_head_t *wq;
 212         struct ext4_inode_info *ei = EXT4_I(inode);
 213
 214 #if (BITS_PER_LONG < 64)
 215         DEFINE_WAIT_BIT(wait, &ei->i_state_flags,
 216                         EXT4_STATE_FC_COMMITTING);
 217         wq = bit_waitqueue(&ei->i_state_flags,
 218                                 EXT4_STATE_FC_COMMITTING);
 219 #else
 220         DEFINE_WAIT_BIT(wait, &ei->i_flags,
 221                         EXT4_STATE_FC_COMMITTING);
 222         wq = bit_waitqueue(&ei->i_flags,
 223                                 EXT4_STATE_FC_COMMITTING);
 224 #endif
 225         lockdep_assert_held(&EXT4_SB(inode->i_sb)->s_fc_lock);
 226         prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
 227         spin_unlock(&EXT4_SB(inode->i_sb)->s_fc_lock);
 228         schedule();
 229         finish_wait(wq, &wait.wq_entry);
 230 }
 231
 232 static bool ext4_fc_disabled(struct super_block *sb)
 233 {
 234         return (!test_opt2(sb, JOURNAL_FAST_COMMIT) ||
 235                 (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY));
 236 }
 237
 238 /*
 239  * Inform Ext4's fast about start of an inode update
 240  *
 241  * This function is called by the high level call VFS callbacks before
 242  * performing any inode update. This function blocks if there's an ongoing
 243  * fast commit on the inode in question.
 244  */
 245 void ext4_fc_start_update(struct inode *inode)
 246 {
 247         struct ext4_inode_info *ei = EXT4_I(inode);
 248
 249         if (ext4_fc_disabled(inode->i_sb))
 250                 return;
 251
 252 restart:
 253         spin_lock(&EXT4_SB(inode->i_sb)->s_fc_lock);
 254         if (list_empty(&ei->i_fc_list))
 255                 goto out;
 256
 257         if (ext4_test_inode_state(inode, EXT4_STATE_FC_COMMITTING)) {
 258                 ext4_fc_wait_committing_inode(inode);
 259                 goto restart;
 260         }
 261 out:
 262         atomic_inc(&ei->i_fc_updates);
 263         spin_unlock(&EXT4_SB(inode->i_sb)->s_fc_lock);
 264 }
 265
 266 /*
 267  * Stop inode update and wake up waiting fast commits if any.
 268  */
 269 void ext4_fc_stop_update(struct inode *inode)
 270 {
 271         struct ext4_inode_info *ei = EXT4_I(inode);
 272
 273         if (ext4_fc_disabled(inode->i_sb))
 274                 return;
 275
 276         if (atomic_dec_and_test(&ei->i_fc_updates))
 277                 wake_up_all(&ei->i_fc_wait);
 278 }
 279
 280 /*
 281  * Remove inode from fast commit list. If the inode is being committed
 282  * we wait until inode commit is done.
 283  */
 284 void ext4_fc_del(struct inode *inode)
 285 {
 286         struct ext4_inode_info *ei = EXT4_I(inode);
 287         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 288         struct ext4_fc_dentry_update *fc_dentry;
 289
 290         if (ext4_fc_disabled(inode->i_sb))
 291                 return;
 292
 293 restart:
 294         spin_lock(&EXT4_SB(inode->i_sb)->s_fc_lock);
 295         if (list_empty(&ei->i_fc_list) && list_empty(&ei->i_fc_dilist)) {
 296                 spin_unlock(&EXT4_SB(inode->i_sb)->s_fc_lock);
 297                 return;
 298         }
 299
 300         if (ext4_test_inode_state(inode, EXT4_STATE_FC_COMMITTING)) {
 301                 ext4_fc_wait_committing_inode(inode);
 302                 goto restart;
 303         }
 304
 305         if (!list_empty(&ei->i_fc_list))
 306                 list_del_init(&ei->i_fc_list);
 307
 308         /*
 309          * Since this inode is getting removed, let's also remove all FC
 310          * dentry create references, since it is not needed to log it anyways.
 311          */
 312         if (list_empty(&ei->i_fc_dilist)) {
 313                 spin_unlock(&sbi->s_fc_lock);
 314                 return;
 315         }
 316
 317         fc_dentry = list_first_entry(&ei->i_fc_dilist, struct ext4_fc_dentry_update, fcd_dilist);
 318         WARN_ON(fc_dentry->fcd_op != EXT4_FC_TAG_CREAT);
 319         list_del_init(&fc_dentry->fcd_list);
 320         list_del_init(&fc_dentry->fcd_dilist);
 321
 322         WARN_ON(!list_empty(&ei->i_fc_dilist));
 323         spin_unlock(&sbi->s_fc_lock);
 324
 325         if (fc_dentry->fcd_name.name &&
 326                 fc_dentry->fcd_name.len > DNAME_INLINE_LEN)
 327                 kfree(fc_dentry->fcd_name.name);
 328         kmem_cache_free(ext4_fc_dentry_cachep, fc_dentry);
 329
 330         return;
 331 }
 332
 333 /*
 334  * Mark file system as fast commit ineligible, and record latest
 335  * ineligible transaction tid. This means until the recorded
 336  * transaction, commit operation would result in a full jbd2 commit.
 337  */
 338 void ext4_fc_mark_ineligible(struct super_block *sb, int reason, handle_t *handle)
 339 {
 340         struct ext4_sb_info *sbi = EXT4_SB(sb);
 341         tid_t tid;
 342
 343         if (ext4_fc_disabled(sb))
 344                 return;
 345
 346         ext4_set_mount_flag(sb, EXT4_MF_FC_INELIGIBLE);
 347         if (handle && !IS_ERR(handle))
 348                 tid = handle->h_transaction->t_tid;
 349         else {
 350                 read_lock(&sbi->s_journal->j_state_lock);
 351                 tid = sbi->s_journal->j_running_transaction ?
 352                                 sbi->s_journal->j_running_transaction->t_tid : 0;
 353                 read_unlock(&sbi->s_journal->j_state_lock);
 354         }
 355         spin_lock(&sbi->s_fc_lock);
 356         if (sbi->s_fc_ineligible_tid < tid)
 357                 sbi->s_fc_ineligible_tid = tid;
 358         spin_unlock(&sbi->s_fc_lock);
 359         WARN_ON(reason >= EXT4_FC_REASON_MAX);
 360         sbi->s_fc_stats.fc_ineligible_reason_count[reason]++;
 361 }
 362
 363 /*
 364  * Generic fast commit tracking function. If this is the first time this we are
 365  * called after a full commit, we initialize fast commit fields and then call
 366  * __fc_track_fn() with update = 0. If we have already been called after a full
 367  * commit, we pass update = 1. Based on that, the track function can determine
 368  * if it needs to track a field for the first time or if it needs to just
 369  * update the previously tracked value.
 370  *
 371  * If enqueue is set, this function enqueues the inode in fast commit list.
 372  */
 373 static int ext4_fc_track_template(
 374         handle_t *handle, struct inode *inode,
 375         int (*__fc_track_fn)(struct inode *, void *, bool),
 376         void *args, int enqueue)
 377 {
 378         bool update = false;
 379         struct ext4_inode_info *ei = EXT4_I(inode);
 380         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 381         tid_t tid = 0;
 382         int ret;
 383
 384         tid = handle->h_transaction->t_tid;
 385         mutex_lock(&ei->i_fc_lock);
 386         if (tid == ei->i_sync_tid) {
 387                 update = true;
 388         } else {
 389                 ext4_fc_reset_inode(inode);
 390                 ei->i_sync_tid = tid;
 391         }
 392         ret = __fc_track_fn(inode, args, update);
 393         mutex_unlock(&ei->i_fc_lock);
 394
 395         if (!enqueue)
 396                 return ret;
 397
 398         spin_lock(&sbi->s_fc_lock);
 399         if (list_empty(&EXT4_I(inode)->i_fc_list))
 400                 list_add_tail(&EXT4_I(inode)->i_fc_list,
 401                                 (sbi->s_journal->j_flags & JBD2_FULL_COMMIT_ONGOING ||
 402                                  sbi->s_journal->j_flags & JBD2_FAST_COMMIT_ONGOING) ?
 403                                 &sbi->s_fc_q[FC_Q_STAGING] :
 404                                 &sbi->s_fc_q[FC_Q_MAIN]);
 405         spin_unlock(&sbi->s_fc_lock);
 406
 407         return ret;
 408 }
 409
 410 struct __track_dentry_update_args {
 411         struct dentry *dentry;
 412         int op;
 413 };
 414
 415 /* __track_fn for directory entry updates. Called with ei->i_fc_lock. */
 416 static int __track_dentry_update(struct inode *inode, void *arg, bool update)
 417 {
 418         struct ext4_fc_dentry_update *node;
 419         struct ext4_inode_info *ei = EXT4_I(inode);
 420         struct __track_dentry_update_args *dentry_update =
 421                 (struct __track_dentry_update_args *)arg;
 422         struct dentry *dentry = dentry_update->dentry;
 423         struct inode *dir = dentry->d_parent->d_inode;
 424         struct super_block *sb = inode->i_sb;
 425         struct ext4_sb_info *sbi = EXT4_SB(sb);
 426
 427         mutex_unlock(&ei->i_fc_lock);
 428
 429         if (IS_ENCRYPTED(dir)) {
 430                 ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_ENCRYPTED_FILENAME,
 431                                         NULL);
 432                 mutex_lock(&ei->i_fc_lock);
 433                 return -EOPNOTSUPP;
 434         }
 435
 436         node = kmem_cache_alloc(ext4_fc_dentry_cachep, GFP_NOFS);
 437         if (!node) {
 438                 ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_NOMEM, NULL);
 439                 mutex_lock(&ei->i_fc_lock);
 440                 return -ENOMEM;
 441         }
 442
 443         node->fcd_op = dentry_update->op;
 444         node->fcd_parent = dir->i_ino;
 445         node->fcd_ino = inode->i_ino;
 446         if (dentry->d_name.len > DNAME_INLINE_LEN) {
 447                 node->fcd_name.name = kmalloc(dentry->d_name.len, GFP_NOFS);
 448                 if (!node->fcd_name.name) {
 449                         kmem_cache_free(ext4_fc_dentry_cachep, node);
 450                         ext4_fc_mark_ineligible(sb, EXT4_FC_REASON_NOMEM, NULL);
 451                         mutex_lock(&ei->i_fc_lock);
 452                         return -ENOMEM;
 453                 }
 454                 memcpy((u8 *)node->fcd_name.name, dentry->d_name.name,
 455                         dentry->d_name.len);
 456         } else {
 457                 memcpy(node->fcd_iname, dentry->d_name.name,
 458                         dentry->d_name.len);
 459                 node->fcd_name.name = node->fcd_iname;
 460         }
 461         node->fcd_name.len = dentry->d_name.len;
 462         INIT_LIST_HEAD(&node->fcd_dilist);
 463         spin_lock(&sbi->s_fc_lock);
 464         if (sbi->s_journal->j_flags & JBD2_FULL_COMMIT_ONGOING ||
 465                 sbi->s_journal->j_flags & JBD2_FAST_COMMIT_ONGOING)
 466                 list_add_tail(&node->fcd_list,
 467                                 &sbi->s_fc_dentry_q[FC_Q_STAGING]);
 468         else
 469                 list_add_tail(&node->fcd_list, &sbi->s_fc_dentry_q[FC_Q_MAIN]);
 470
 471         /*
 472          * This helps us keep a track of all fc_dentry updates which is part of
 473          * this ext4 inode. So in case the inode is getting unlinked, before
 474          * even we get a chance to fsync, we could remove all fc_dentry
 475          * references while evicting the inode in ext4_fc_del().
 476          * Also with this, we don't need to loop over all the inodes in
 477          * sbi->s_fc_q to get the corresponding inode in
 478          * ext4_fc_commit_dentry_updates().
 479          */
 480         if (dentry_update->op == EXT4_FC_TAG_CREAT) {
 481                 WARN_ON(!list_empty(&ei->i_fc_dilist));
 482                 list_add_tail(&node->fcd_dilist, &ei->i_fc_dilist);
 483         }
 484         spin_unlock(&sbi->s_fc_lock);
 485         mutex_lock(&ei->i_fc_lock);
 486
 487         return 0;
 488 }
 489
 490 void __ext4_fc_track_unlink(handle_t *handle,
 491                 struct inode *inode, struct dentry *dentry)
 492 {
 493         struct __track_dentry_update_args args;
 494         int ret;
 495
 496         args.dentry = dentry;
 497         args.op = EXT4_FC_TAG_UNLINK;
 498
 499         ret = ext4_fc_track_template(handle, inode, __track_dentry_update,
 500                                         (void *)&args, 0);
 501         trace_ext4_fc_track_unlink(handle, inode, dentry, ret);
 502 }
 503
 504 void ext4_fc_track_unlink(handle_t *handle, struct dentry *dentry)
 505 {
 506         struct inode *inode = d_inode(dentry);
 507
 508         if (ext4_fc_disabled(inode->i_sb))
 509                 return;
 510
 511         if (ext4_test_mount_flag(inode->i_sb, EXT4_MF_FC_INELIGIBLE))
 512                 return;
 513
 514         __ext4_fc_track_unlink(handle, inode, dentry);
 515 }
 516
 517 void __ext4_fc_track_link(handle_t *handle,
 518         struct inode *inode, struct dentry *dentry)
 519 {
 520         struct __track_dentry_update_args args;
 521         int ret;
 522
 523         args.dentry = dentry;
 524         args.op = EXT4_FC_TAG_LINK;
 525
 526         ret = ext4_fc_track_template(handle, inode, __track_dentry_update,
 527                                         (void *)&args, 0);
 528         trace_ext4_fc_track_link(handle, inode, dentry, ret);
 529 }
 530
 531 void ext4_fc_track_link(handle_t *handle, struct dentry *dentry)
 532 {
 533         struct inode *inode = d_inode(dentry);
 534
 535         if (ext4_fc_disabled(inode->i_sb))
 536                 return;
 537
 538         if (ext4_test_mount_flag(inode->i_sb, EXT4_MF_FC_INELIGIBLE))
 539                 return;
 540
 541         __ext4_fc_track_link(handle, inode, dentry);
 542 }
 543
 544 void __ext4_fc_track_create(handle_t *handle, struct inode *inode,
 545                           struct dentry *dentry)
 546 {
 547         struct __track_dentry_update_args args;
 548         int ret;
 549
 550         args.dentry = dentry;
 551         args.op = EXT4_FC_TAG_CREAT;
 552
 553         ret = ext4_fc_track_template(handle, inode, __track_dentry_update,
 554                                         (void *)&args, 0);
 555         trace_ext4_fc_track_create(handle, inode, dentry, ret);
 556 }
 557
 558 void ext4_fc_track_create(handle_t *handle, struct dentry *dentry)
 559 {
 560         struct inode *inode = d_inode(dentry);
 561
 562         if (ext4_fc_disabled(inode->i_sb))
 563                 return;
 564
 565         if (ext4_test_mount_flag(inode->i_sb, EXT4_MF_FC_INELIGIBLE))
 566                 return;
 567
 568         __ext4_fc_track_create(handle, inode, dentry);
 569 }
 570
 571 /* __track_fn for inode tracking */
 572 static int __track_inode(struct inode *inode, void *arg, bool update)
 573 {
 574         if (update)
 575                 return -EEXIST;
 576
 577         EXT4_I(inode)->i_fc_lblk_len = 0;
 578
 579         return 0;
 580 }
 581
 582 void ext4_fc_track_inode(handle_t *handle, struct inode *inode)
 583 {
 584         int ret;
 585
 586         if (S_ISDIR(inode->i_mode))
 587                 return;
 588
 589         if (ext4_fc_disabled(inode->i_sb))
 590                 return;
 591
 592         if (ext4_should_journal_data(inode)) {
 593                 ext4_fc_mark_ineligible(inode->i_sb,
 594                                         EXT4_FC_REASON_INODE_JOURNAL_DATA, handle);
 595                 return;
 596         }
 597
 598         if (ext4_test_mount_flag(inode->i_sb, EXT4_MF_FC_INELIGIBLE))
 599                 return;
 600
 601         ret = ext4_fc_track_template(handle, inode, __track_inode, NULL, 1);
 602         trace_ext4_fc_track_inode(handle, inode, ret);
 603 }
 604
 605 struct __track_range_args {
 606         ext4_lblk_t start, end;
 607 };
 608
 609 /* __track_fn for tracking data updates */
 610 static int __track_range(struct inode *inode, void *arg, bool update)
 611 {
 612         struct ext4_inode_info *ei = EXT4_I(inode);
 613         ext4_lblk_t oldstart;
 614         struct __track_range_args *__arg =
 615                 (struct __track_range_args *)arg;
 616
 617         if (inode->i_ino < EXT4_FIRST_INO(inode->i_sb)) {
 618                 ext4_debug("Special inode %ld being modified\n", inode->i_ino);
 619                 return -ECANCELED;
 620         }
 621
 622         oldstart = ei->i_fc_lblk_start;
 623
 624         if (update && ei->i_fc_lblk_len > 0) {
 625                 ei->i_fc_lblk_start = min(ei->i_fc_lblk_start, __arg->start);
 626                 ei->i_fc_lblk_len =
 627                         max(oldstart + ei->i_fc_lblk_len - 1, __arg->end) -
 628                                 ei->i_fc_lblk_start + 1;
 629         } else {
 630                 ei->i_fc_lblk_start = __arg->start;
 631                 ei->i_fc_lblk_len = __arg->end - __arg->start + 1;
 632         }
 633
 634         return 0;
 635 }
 636
 637 void ext4_fc_track_range(handle_t *handle, struct inode *inode, ext4_lblk_t start,
 638                          ext4_lblk_t end)
 639 {
 640         struct __track_range_args args;
 641         int ret;
 642
 643         if (S_ISDIR(inode->i_mode))
 644                 return;
 645
 646         if (ext4_fc_disabled(inode->i_sb))
 647                 return;
 648
 649         if (ext4_test_mount_flag(inode->i_sb, EXT4_MF_FC_INELIGIBLE))
 650                 return;
 651
 652         args.start = start;
 653         args.end = end;
 654
 655         ret = ext4_fc_track_template(handle, inode,  __track_range, &args, 1);
 656
 657         trace_ext4_fc_track_range(handle, inode, start, end, ret);
 658 }
 659
 660 static void ext4_fc_submit_bh(struct super_block *sb, bool is_tail)
 661 {
 662         blk_opf_t write_flags = REQ_SYNC;
 663         struct buffer_head *bh = EXT4_SB(sb)->s_fc_bh;
 664
 665         /* Add REQ_FUA | REQ_PREFLUSH only its tail */
 666         if (test_opt(sb, BARRIER) && is_tail)
 667                 write_flags |= REQ_FUA | REQ_PREFLUSH;
 668         lock_buffer(bh);
 669         set_buffer_dirty(bh);
 670         set_buffer_uptodate(bh);
 671         bh->b_end_io = ext4_end_buffer_io_sync;
 672         submit_bh(REQ_OP_WRITE | write_flags, bh);
 673         EXT4_SB(sb)->s_fc_bh = NULL;
 674 }
 675
 676 /* Ext4 commit path routines */
 677
 678 /*
 679  * Allocate len bytes on a fast commit buffer.
 680  *
 681  * During the commit time this function is used to manage fast commit
 682  * block space. We don't split a fast commit log onto different
 683  * blocks. So this function makes sure that if there's not enough space
 684  * on the current block, the remaining space in the current block is
 685  * marked as unused by adding EXT4_FC_TAG_PAD tag. In that case,
 686  * new block is from jbd2 and CRC is updated to reflect the padding
 687  * we added.
 688  */
 689 static u8 *ext4_fc_reserve_space(struct super_block *sb, int len, u32 *crc)
 690 {
 691         struct ext4_fc_tl tl;
 692         struct ext4_sb_info *sbi = EXT4_SB(sb);
 693         struct buffer_head *bh;
 694         int bsize = sbi->s_journal->j_blocksize;
 695         int ret, off = sbi->s_fc_bytes % bsize;
 696         int remaining;
 697         u8 *dst;
 698
 699         /*
 700          * If 'len' is too long to fit in any block alongside a PAD tlv, then we
 701          * cannot fulfill the request.
 702          */
 703         if (len > bsize - EXT4_FC_TAG_BASE_LEN)
 704                 return NULL;
 705
 706         if (!sbi->s_fc_bh) {
 707                 ret = jbd2_fc_get_buf(EXT4_SB(sb)->s_journal, &bh);
 708                 if (ret)
 709                         return NULL;
 710                 sbi->s_fc_bh = bh;
 711         }
 712         dst = sbi->s_fc_bh->b_data + off;
 713
 714         /*
 715          * Allocate the bytes in the current block if we can do so while still
 716          * leaving enough space for a PAD tlv.
 717          */
 718         remaining = bsize - EXT4_FC_TAG_BASE_LEN - off;
 719         if (len <= remaining) {
 720                 sbi->s_fc_bytes += len;
 721                 return dst;
 722         }
 723
 724         /*
 725          * Else, terminate the current block with a PAD tlv, then allocate a new
 726          * block and allocate the bytes at the start of that new block.
 727          */
 728
 729         tl.fc_tag = cpu_to_le16(EXT4_FC_TAG_PAD);
 730         tl.fc_len = cpu_to_le16(remaining);
 731         memcpy(dst, &tl, EXT4_FC_TAG_BASE_LEN);
 732         memset(dst + EXT4_FC_TAG_BASE_LEN, 0, remaining);
 733         *crc = ext4_chksum(sbi, *crc, sbi->s_fc_bh->b_data, bsize);
 734
 735         ext4_fc_submit_bh(sb, false);
 736
 737         ret = jbd2_fc_get_buf(EXT4_SB(sb)->s_journal, &bh);
 738         if (ret)
 739                 return NULL;
 740         sbi->s_fc_bh = bh;
 741         sbi->s_fc_bytes += bsize - off + len;
 742         return sbi->s_fc_bh->b_data;
 743 }
 744
 745 /*
 746  * Complete a fast commit by writing tail tag.
 747  *
 748  * Writing tail tag marks the end of a fast commit. In order to guarantee
 749  * atomicity, after writing tail tag, even if there's space remaining
 750  * in the block, next commit shouldn't use it. That's why tail tag
 751  * has the length as that of the remaining space on the block.
 752  */
 753 static int ext4_fc_write_tail(struct super_block *sb, u32 crc)
 754 {
 755         struct ext4_sb_info *sbi = EXT4_SB(sb);
 756         struct ext4_fc_tl tl;
 757         struct ext4_fc_tail tail;
 758         int off, bsize = sbi->s_journal->j_blocksize;
 759         u8 *dst;
 760
 761         /*
 762          * ext4_fc_reserve_space takes care of allocating an extra block if
 763          * there's no enough space on this block for accommodating this tail.
 764          */
 765         dst = ext4_fc_reserve_space(sb, EXT4_FC_TAG_BASE_LEN + sizeof(tail), &crc);
 766         if (!dst)
 767                 return -ENOSPC;
 768
 769         off = sbi->s_fc_bytes % bsize;
 770
 771         tl.fc_tag = cpu_to_le16(EXT4_FC_TAG_TAIL);
 772         tl.fc_len = cpu_to_le16(bsize - off + sizeof(struct ext4_fc_tail));
 773         sbi->s_fc_bytes = round_up(sbi->s_fc_bytes, bsize);
 774
 775         memcpy(dst, &tl, EXT4_FC_TAG_BASE_LEN);
 776         dst += EXT4_FC_TAG_BASE_LEN;
 777         tail.fc_tid = cpu_to_le32(sbi->s_journal->j_running_transaction->t_tid);
 778         memcpy(dst, &tail.fc_tid, sizeof(tail.fc_tid));
 779         dst += sizeof(tail.fc_tid);
 780         crc = ext4_chksum(sbi, crc, sbi->s_fc_bh->b_data,
 781                           dst - (u8 *)sbi->s_fc_bh->b_data);
 782         tail.fc_crc = cpu_to_le32(crc);
 783         memcpy(dst, &tail.fc_crc, sizeof(tail.fc_crc));
 784         dst += sizeof(tail.fc_crc);
 785         memset(dst, 0, bsize - off); /* Don't leak uninitialized memory. */
 786
 787         ext4_fc_submit_bh(sb, true);
 788
 789         return 0;
 790 }
 791
 792 /*
 793  * Adds tag, length, value and updates CRC. Returns true if tlv was added.
 794  * Returns false if there's not enough space.
 795  */
 796 static bool ext4_fc_add_tlv(struct super_block *sb, u16 tag, u16 len, u8 *val,
 797                            u32 *crc)
 798 {
 799         struct ext4_fc_tl tl;
 800         u8 *dst;
 801
 802         dst = ext4_fc_reserve_space(sb, EXT4_FC_TAG_BASE_LEN + len, crc);
 803         if (!dst)
 804                 return false;
 805
 806         tl.fc_tag = cpu_to_le16(tag);
 807         tl.fc_len = cpu_to_le16(len);
 808
 809         memcpy(dst, &tl, EXT4_FC_TAG_BASE_LEN);
 810         memcpy(dst + EXT4_FC_TAG_BASE_LEN, val, len);
 811
 812         return true;
 813 }
 814
 815 /* Same as above, but adds dentry tlv. */
 816 static bool ext4_fc_add_dentry_tlv(struct super_block *sb, u32 *crc,
 817                                    struct ext4_fc_dentry_update *fc_dentry)
 818 {
 819         struct ext4_fc_dentry_info fcd;
 820         struct ext4_fc_tl tl;
 821         int dlen = fc_dentry->fcd_name.len;
 822         u8 *dst = ext4_fc_reserve_space(sb,
 823                         EXT4_FC_TAG_BASE_LEN + sizeof(fcd) + dlen, crc);
 824
 825         if (!dst)
 826                 return false;
 827
 828         fcd.fc_parent_ino = cpu_to_le32(fc_dentry->fcd_parent);
 829         fcd.fc_ino = cpu_to_le32(fc_dentry->fcd_ino);
 830         tl.fc_tag = cpu_to_le16(fc_dentry->fcd_op);
 831         tl.fc_len = cpu_to_le16(sizeof(fcd) + dlen);
 832         memcpy(dst, &tl, EXT4_FC_TAG_BASE_LEN);
 833         dst += EXT4_FC_TAG_BASE_LEN;
 834         memcpy(dst, &fcd, sizeof(fcd));
 835         dst += sizeof(fcd);
 836         memcpy(dst, fc_dentry->fcd_name.name, dlen);
 837
 838         return true;
 839 }
 840
 841 /*
 842  * Writes inode in the fast commit space under TLV with tag @tag.
 843  * Returns 0 on success, error on failure.
 844  */
 845 static int ext4_fc_write_inode(struct inode *inode, u32 *crc)
 846 {
 847         struct ext4_inode_info *ei = EXT4_I(inode);
 848         int inode_len = EXT4_GOOD_OLD_INODE_SIZE;
 849         int ret;
 850         struct ext4_iloc iloc;
 851         struct ext4_fc_inode fc_inode;
 852         struct ext4_fc_tl tl;
 853         u8 *dst;
 854
 855         ret = ext4_get_inode_loc(inode, &iloc);
 856         if (ret)
 857                 return ret;
 858
 859         if (ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA))
 860                 inode_len = EXT4_INODE_SIZE(inode->i_sb);
 861         else if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE)
 862                 inode_len += ei->i_extra_isize;
 863
 864         fc_inode.fc_ino = cpu_to_le32(inode->i_ino);
 865         tl.fc_tag = cpu_to_le16(EXT4_FC_TAG_INODE);
 866         tl.fc_len = cpu_to_le16(inode_len + sizeof(fc_inode.fc_ino));
 867
 868         ret = -ECANCELED;
 869         dst = ext4_fc_reserve_space(inode->i_sb,
 870                 EXT4_FC_TAG_BASE_LEN + inode_len + sizeof(fc_inode.fc_ino), crc);
 871         if (!dst)
 872                 goto err;
 873
 874         memcpy(dst, &tl, EXT4_FC_TAG_BASE_LEN);
 875         dst += EXT4_FC_TAG_BASE_LEN;
 876         memcpy(dst, &fc_inode, sizeof(fc_inode));
 877         dst += sizeof(fc_inode);
 878         memcpy(dst, (u8 *)ext4_raw_inode(&iloc), inode_len);
 879         ret = 0;
 880 err:
 881         brelse(iloc.bh);
 882         return ret;
 883 }
 884
 885 /*
 886  * Writes updated data ranges for the inode in question. Updates CRC.
 887  * Returns 0 on success, error otherwise.
 888  */
 889 static int ext4_fc_write_inode_data(struct inode *inode, u32 *crc)
 890 {
 891         ext4_lblk_t old_blk_size, cur_lblk_off, new_blk_size;
 892         struct ext4_inode_info *ei = EXT4_I(inode);
 893         struct ext4_map_blocks map;
 894         struct ext4_fc_add_range fc_ext;
 895         struct ext4_fc_del_range lrange;
 896         struct ext4_extent *ex;
 897         int ret;
 898
 899         mutex_lock(&ei->i_fc_lock);
 900         if (ei->i_fc_lblk_len == 0) {
 901                 mutex_unlock(&ei->i_fc_lock);
 902                 return 0;
 903         }
 904         old_blk_size = ei->i_fc_lblk_start;
 905         new_blk_size = ei->i_fc_lblk_start + ei->i_fc_lblk_len - 1;
 906         ei->i_fc_lblk_len = 0;
 907         mutex_unlock(&ei->i_fc_lock);
 908
 909         cur_lblk_off = old_blk_size;
 910         ext4_debug("will try writing %d to %d for inode %ld\n",
 911                    cur_lblk_off, new_blk_size, inode->i_ino);
 912
 913         while (cur_lblk_off <= new_blk_size) {
 914                 map.m_lblk = cur_lblk_off;
 915                 map.m_len = new_blk_size - cur_lblk_off + 1;
 916                 ret = ext4_map_blocks(NULL, inode, &map, 0);
 917                 if (ret < 0)
 918                         return -ECANCELED;
 919
 920                 if (map.m_len == 0) {
 921                         cur_lblk_off++;
 922                         continue;
 923                 }
 924
 925                 if (ret == 0) {
 926                         lrange.fc_ino = cpu_to_le32(inode->i_ino);
 927                         lrange.fc_lblk = cpu_to_le32(map.m_lblk);
 928                         lrange.fc_len = cpu_to_le32(map.m_len);
 929                         if (!ext4_fc_add_tlv(inode->i_sb, EXT4_FC_TAG_DEL_RANGE,
 930                                             sizeof(lrange), (u8 *)&lrange, crc))
 931                                 return -ENOSPC;
 932                 } else {
 933                         unsigned int max = (map.m_flags & EXT4_MAP_UNWRITTEN) ?
 934                                 EXT_UNWRITTEN_MAX_LEN : EXT_INIT_MAX_LEN;
 935
 936                         /* Limit the number of blocks in one extent */
 937                         map.m_len = min(max, map.m_len);
 938
 939                         fc_ext.fc_ino = cpu_to_le32(inode->i_ino);
 940                         ex = (struct ext4_extent *)&fc_ext.fc_ex;
 941                         ex->ee_block = cpu_to_le32(map.m_lblk);
 942                         ex->ee_len = cpu_to_le16(map.m_len);
 943                         ext4_ext_store_pblock(ex, map.m_pblk);
 944                         if (map.m_flags & EXT4_MAP_UNWRITTEN)
 945                                 ext4_ext_mark_unwritten(ex);
 946                         else
 947                                 ext4_ext_mark_initialized(ex);
 948                         if (!ext4_fc_add_tlv(inode->i_sb, EXT4_FC_TAG_ADD_RANGE,
 949                                             sizeof(fc_ext), (u8 *)&fc_ext, crc))
 950                                 return -ENOSPC;
 951                 }
 952
 953                 cur_lblk_off += map.m_len;
 954         }
 955
 956         return 0;
 957 }
 958
 959
 960 /* Submit data for all the fast commit inodes */
 961 static int ext4_fc_submit_inode_data_all(journal_t *journal)
 962 {
 963         struct super_block *sb = journal->j_private;
 964         struct ext4_sb_info *sbi = EXT4_SB(sb);
 965         struct ext4_inode_info *ei;
 966         int ret = 0;
 967
 968         spin_lock(&sbi->s_fc_lock);
 969         list_for_each_entry(ei, &sbi->s_fc_q[FC_Q_MAIN], i_fc_list) {
 970                 ext4_set_inode_state(&ei->vfs_inode, EXT4_STATE_FC_COMMITTING);
 971                 while (atomic_read(&ei->i_fc_updates)) {
 972                         DEFINE_WAIT(wait);
 973
 974                         prepare_to_wait(&ei->i_fc_wait, &wait,
 975                                                 TASK_UNINTERRUPTIBLE);
 976                         if (atomic_read(&ei->i_fc_updates)) {
 977                                 spin_unlock(&sbi->s_fc_lock);
 978                                 schedule();
 979                                 spin_lock(&sbi->s_fc_lock);
 980                         }
 981                         finish_wait(&ei->i_fc_wait, &wait);
 982                 }
 983                 spin_unlock(&sbi->s_fc_lock);
 984                 ret = jbd2_submit_inode_data(journal, ei->jinode);
 985                 if (ret)
 986                         return ret;
 987                 spin_lock(&sbi->s_fc_lock);
 988         }
 989         spin_unlock(&sbi->s_fc_lock);
 990
 991         return ret;
 992 }
 993
 994 /* Wait for completion of data for all the fast commit inodes */
 995 static int ext4_fc_wait_inode_data_all(journal_t *journal)
 996 {
 997         struct super_block *sb = journal->j_private;
 998         struct ext4_sb_info *sbi = EXT4_SB(sb);
 999         struct ext4_inode_info *pos, *n;
1000         int ret = 0;
1001
1002         spin_lock(&sbi->s_fc_lock);
1003         list_for_each_entry_safe(pos, n, &sbi->s_fc_q[FC_Q_MAIN], i_fc_list) {
1004                 if (!ext4_test_inode_state(&pos->vfs_inode,
1005                                            EXT4_STATE_FC_COMMITTING))
1006                         continue;
1007                 spin_unlock(&sbi->s_fc_lock);
1008
1009                 ret = jbd2_wait_inode_data(journal, pos->jinode);
1010                 if (ret)
1011                         return ret;
1012                 spin_lock(&sbi->s_fc_lock);
1013         }
1014         spin_unlock(&sbi->s_fc_lock);
1015
1016         return 0;
1017 }
1018
1019 /* Commit all the directory entry updates */
1020 static int ext4_fc_commit_dentry_updates(journal_t *journal, u32 *crc)
1021 __acquires(&sbi->s_fc_lock)
1022 __releases(&sbi->s_fc_lock)
1023 {
1024         struct super_block *sb = journal->j_private;
1025         struct ext4_sb_info *sbi = EXT4_SB(sb);
1026         struct ext4_fc_dentry_update *fc_dentry, *fc_dentry_n;
1027         struct inode *inode;
1028         struct ext4_inode_info *ei;
1029         int ret;
1030
1031         if (list_empty(&sbi->s_fc_dentry_q[FC_Q_MAIN]))
1032                 return 0;
1033         list_for_each_entry_safe(fc_dentry, fc_dentry_n,
1034                                  &sbi->s_fc_dentry_q[FC_Q_MAIN], fcd_list) {
1035                 if (fc_dentry->fcd_op != EXT4_FC_TAG_CREAT) {
1036                         spin_unlock(&sbi->s_fc_lock);
1037                         if (!ext4_fc_add_dentry_tlv(sb, crc, fc_dentry)) {
1038                                 ret = -ENOSPC;
1039                                 goto lock_and_exit;
1040                         }
1041                         spin_lock(&sbi->s_fc_lock);
1042                         continue;
1043                 }
1044                 /*
1045                  * With fcd_dilist we need not loop in sbi->s_fc_q to get the
1046                  * corresponding inode pointer
1047                  */
1048                 WARN_ON(list_empty(&fc_dentry->fcd_dilist));
1049                 ei = list_first_entry(&fc_dentry->fcd_dilist,
1050                                 struct ext4_inode_info, i_fc_dilist);
1051                 inode = &ei->vfs_inode;
1052                 WARN_ON(inode->i_ino != fc_dentry->fcd_ino);
1053
1054                 spin_unlock(&sbi->s_fc_lock);
1055
1056                 /*
1057                  * We first write the inode and then the create dirent. This
1058                  * allows the recovery code to create an unnamed inode first
1059                  * and then link it to a directory entry. This allows us
1060                  * to use namei.c routines almost as is and simplifies
1061                  * the recovery code.
1062                  */
1063                 ret = ext4_fc_write_inode(inode, crc);
1064                 if (ret)
1065                         goto lock_and_exit;
1066
1067                 ret = ext4_fc_write_inode_data(inode, crc);
1068                 if (ret)
1069                         goto lock_and_exit;
1070
1071                 if (!ext4_fc_add_dentry_tlv(sb, crc, fc_dentry)) {
1072                         ret = -ENOSPC;
1073                         goto lock_and_exit;
1074                 }
1075
1076                 spin_lock(&sbi->s_fc_lock);
1077         }
1078         return 0;
1079 lock_and_exit:
1080         spin_lock(&sbi->s_fc_lock);
1081         return ret;
1082 }
1083
1084 static int ext4_fc_perform_commit(journal_t *journal)
1085 {
1086         struct super_block *sb = journal->j_private;
1087         struct ext4_sb_info *sbi = EXT4_SB(sb);
1088         struct ext4_inode_info *iter;
1089         struct ext4_fc_head head;
1090         struct inode *inode;
1091         struct blk_plug plug;
1092         int ret = 0;
1093         u32 crc = 0;
1094
1095         ret = ext4_fc_submit_inode_data_all(journal);
1096         if (ret)
1097                 return ret;
1098
1099         ret = ext4_fc_wait_inode_data_all(journal);
1100         if (ret)
1101                 return ret;
1102
1103         /*
1104          * If file system device is different from journal device, issue a cache
1105          * flush before we start writing fast commit blocks.
1106          */
1107         if (journal->j_fs_dev != journal->j_dev)
1108                 blkdev_issue_flush(journal->j_fs_dev);
1109
1110         blk_start_plug(&plug);
1111         if (sbi->s_fc_bytes == 0) {
1112                 /*
1113                  * Add a head tag only if this is the first fast commit
1114                  * in this TID.
1115                  */
1116                 head.fc_features = cpu_to_le32(EXT4_FC_SUPPORTED_FEATURES);
1117                 head.fc_tid = cpu_to_le32(
1118                         sbi->s_journal->j_running_transaction->t_tid);
1119                 if (!ext4_fc_add_tlv(sb, EXT4_FC_TAG_HEAD, sizeof(head),
1120                         (u8 *)&head, &crc)) {
1121                         ret = -ENOSPC;
1122                         goto out;
1123                 }
1124         }
1125
1126         spin_lock(&sbi->s_fc_lock);
1127         ret = ext4_fc_commit_dentry_updates(journal, &crc);
1128         if (ret) {
1129                 spin_unlock(&sbi->s_fc_lock);
1130                 goto out;
1131         }
1132
1133         list_for_each_entry(iter, &sbi->s_fc_q[FC_Q_MAIN], i_fc_list) {
1134                 inode = &iter->vfs_inode;
1135                 if (!ext4_test_inode_state(inode, EXT4_STATE_FC_COMMITTING))
1136                         continue;
1137
1138                 spin_unlock(&sbi->s_fc_lock);
1139                 ret = ext4_fc_write_inode_data(inode, &crc);
1140                 if (ret)
1141                         goto out;
1142                 ret = ext4_fc_write_inode(inode, &crc);
1143                 if (ret)
1144                         goto out;
1145                 spin_lock(&sbi->s_fc_lock);
1146         }
1147         spin_unlock(&sbi->s_fc_lock);
1148
1149         ret = ext4_fc_write_tail(sb, crc);
1150
1151 out:
1152         blk_finish_plug(&plug);
1153         return ret;
1154 }
1155
1156 static void ext4_fc_update_stats(struct super_block *sb, int status,
1157                                  u64 commit_time, int nblks, tid_t commit_tid)
1158 {
1159         struct ext4_fc_stats *stats = &EXT4_SB(sb)->s_fc_stats;
1160
1161         ext4_debug("Fast commit ended with status = %d for tid %u",
1162                         status, commit_tid);
1163         if (status == EXT4_FC_STATUS_OK) {
1164                 stats->fc_num_commits++;
1165                 stats->fc_numblks += nblks;
1166                 if (likely(stats->s_fc_avg_commit_time))
1167                         stats->s_fc_avg_commit_time =
1168                                 (commit_time +
1169                                  stats->s_fc_avg_commit_time * 3) / 4;
1170                 else
1171                         stats->s_fc_avg_commit_time = commit_time;
1172         } else if (status == EXT4_FC_STATUS_FAILED ||
1173                    status == EXT4_FC_STATUS_INELIGIBLE) {
1174                 if (status == EXT4_FC_STATUS_FAILED)
1175                         stats->fc_failed_commits++;
1176                 stats->fc_ineligible_commits++;
1177         } else {
1178                 stats->fc_skipped_commits++;
1179         }
1180         trace_ext4_fc_commit_stop(sb, nblks, status, commit_tid);
1181 }
1182
1183 /*
1184  * The main commit entry point. Performs a fast commit for transaction
1185  * commit_tid if needed. If it's not possible to perform a fast commit
1186  * due to various reasons, we fall back to full commit. Returns 0
1187  * on success, error otherwise.
1188  */
1189 int ext4_fc_commit(journal_t *journal, tid_t commit_tid)
1190 {
1191         struct super_block *sb = journal->j_private;
1192         struct ext4_sb_info *sbi = EXT4_SB(sb);
1193         int nblks = 0, ret, bsize = journal->j_blocksize;
1194         int subtid = atomic_read(&sbi->s_fc_subtid);
1195         int status = EXT4_FC_STATUS_OK, fc_bufs_before = 0;
1196         ktime_t start_time, commit_time;
1197
1198         if (!test_opt2(sb, JOURNAL_FAST_COMMIT))
1199                 return jbd2_complete_transaction(journal, commit_tid);
1200
1201         trace_ext4_fc_commit_start(sb, commit_tid);
1202
1203         start_time = ktime_get();
1204
1205 restart_fc:
1206         ret = jbd2_fc_begin_commit(journal, commit_tid);
1207         if (ret == -EALREADY) {
1208                 /* There was an ongoing commit, check if we need to restart */
1209                 if (atomic_read(&sbi->s_fc_subtid) <= subtid &&
1210                         commit_tid > journal->j_commit_sequence)
1211                         goto restart_fc;
1212                 ext4_fc_update_stats(sb, EXT4_FC_STATUS_SKIPPED, 0, 0,
1213                                 commit_tid);
1214                 return 0;
1215         } else if (ret) {
1216                 /*
1217                  * Commit couldn't start. Just update stats and perform a
1218                  * full commit.
1219                  */
1220                 ext4_fc_update_stats(sb, EXT4_FC_STATUS_FAILED, 0, 0,
1221                                 commit_tid);
1222                 return jbd2_complete_transaction(journal, commit_tid);
1223         }
1224
1225         /*
1226          * After establishing journal barrier via jbd2_fc_begin_commit(), check
1227          * if we are fast commit ineligible.
1228          */
1229         if (ext4_test_mount_flag(sb, EXT4_MF_FC_INELIGIBLE)) {
1230                 status = EXT4_FC_STATUS_INELIGIBLE;
1231                 goto fallback;
1232         }
1233
1234         fc_bufs_before = (sbi->s_fc_bytes + bsize - 1) / bsize;
1235         ret = ext4_fc_perform_commit(journal);
1236         if (ret < 0) {
1237                 status = EXT4_FC_STATUS_FAILED;
1238                 goto fallback;
1239         }
1240         nblks = (sbi->s_fc_bytes + bsize - 1) / bsize - fc_bufs_before;
1241         ret = jbd2_fc_wait_bufs(journal, nblks);
1242         if (ret < 0) {
1243                 status = EXT4_FC_STATUS_FAILED;
1244                 goto fallback;
1245         }
1246         atomic_inc(&sbi->s_fc_subtid);
1247         ret = jbd2_fc_end_commit(journal);
1248         /*
1249          * weight the commit time higher than the average time so we
1250          * don't react too strongly to vast changes in the commit time
1251          */
1252         commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1253         ext4_fc_update_stats(sb, status, commit_time, nblks, commit_tid);
1254         return ret;
1255
1256 fallback:
1257         ret = jbd2_fc_end_commit_fallback(journal);
1258         ext4_fc_update_stats(sb, status, 0, 0, commit_tid);
1259         return ret;
1260 }
1261
1262 /*
1263  * Fast commit cleanup routine. This is called after every fast commit and
1264  * full commit. full is true if we are called after a full commit.
1265  */
1266 static void ext4_fc_cleanup(journal_t *journal, int full, tid_t tid)
1267 {
1268         struct super_block *sb = journal->j_private;
1269         struct ext4_sb_info *sbi = EXT4_SB(sb);
1270         struct ext4_inode_info *iter, *iter_n;
1271         struct ext4_fc_dentry_update *fc_dentry;
1272
1273         if (full && sbi->s_fc_bh)
1274                 sbi->s_fc_bh = NULL;
1275
1276         trace_ext4_fc_cleanup(journal, full, tid);
1277         jbd2_fc_release_bufs(journal);
1278
1279         spin_lock(&sbi->s_fc_lock);
1280         list_for_each_entry_safe(iter, iter_n, &sbi->s_fc_q[FC_Q_MAIN],
1281                                  i_fc_list) {
1282                 list_del_init(&iter->i_fc_list);
1283                 ext4_clear_inode_state(&iter->vfs_inode,
1284                                        EXT4_STATE_FC_COMMITTING);
1285                 if (iter->i_sync_tid <= tid)
1286                         ext4_fc_reset_inode(&iter->vfs_inode);
1287                 /* Make sure EXT4_STATE_FC_COMMITTING bit is clear */
1288                 smp_mb();
1289 #if (BITS_PER_LONG < 64)
1290                 wake_up_bit(&iter->i_state_flags, EXT4_STATE_FC_COMMITTING);
1291 #else
1292                 wake_up_bit(&iter->i_flags, EXT4_STATE_FC_COMMITTING);
1293 #endif
1294         }
1295
1296         while (!list_empty(&sbi->s_fc_dentry_q[FC_Q_MAIN])) {
1297                 fc_dentry = list_first_entry(&sbi->s_fc_dentry_q[FC_Q_MAIN],
1298                                              struct ext4_fc_dentry_update,
1299                                              fcd_list);
1300                 list_del_init(&fc_dentry->fcd_list);
1301                 list_del_init(&fc_dentry->fcd_dilist);
1302                 spin_unlock(&sbi->s_fc_lock);
1303
1304                 if (fc_dentry->fcd_name.name &&
1305                         fc_dentry->fcd_name.len > DNAME_INLINE_LEN)
1306                         kfree(fc_dentry->fcd_name.name);
1307                 kmem_cache_free(ext4_fc_dentry_cachep, fc_dentry);
1308                 spin_lock(&sbi->s_fc_lock);
1309         }
1310
1311         list_splice_init(&sbi->s_fc_dentry_q[FC_Q_STAGING],
1312                                 &sbi->s_fc_dentry_q[FC_Q_MAIN]);
1313         list_splice_init(&sbi->s_fc_q[FC_Q_STAGING],
1314                                 &sbi->s_fc_q[FC_Q_MAIN]);
1315
1316         if (tid >= sbi->s_fc_ineligible_tid) {
1317                 sbi->s_fc_ineligible_tid = 0;
1318                 ext4_clear_mount_flag(sb, EXT4_MF_FC_INELIGIBLE);
1319         }
1320
1321         if (full)
1322                 sbi->s_fc_bytes = 0;
1323         spin_unlock(&sbi->s_fc_lock);
1324         trace_ext4_fc_stats(sb);
1325 }
1326
1327 /* Ext4 Replay Path Routines */
1328
1329 /* Helper struct for dentry replay routines */
1330 struct dentry_info_args {
1331         int parent_ino, dname_len, ino, inode_len;
1332         char *dname;
1333 };
1334
1335 /* Same as struct ext4_fc_tl, but uses native endianness fields */
1336 struct ext4_fc_tl_mem {
1337         u16 fc_tag;
1338         u16 fc_len;
1339 };
1340
1341 static inline void tl_to_darg(struct dentry_info_args *darg,
1342                               struct ext4_fc_tl_mem *tl, u8 *val)
1343 {
1344         struct ext4_fc_dentry_info fcd;
1345
1346         memcpy(&fcd, val, sizeof(fcd));
1347
1348         darg->parent_ino = le32_to_cpu(fcd.fc_parent_ino);
1349         darg->ino = le32_to_cpu(fcd.fc_ino);
1350         darg->dname = val + offsetof(struct ext4_fc_dentry_info, fc_dname);
1351         darg->dname_len = tl->fc_len - sizeof(struct ext4_fc_dentry_info);
1352 }
1353
1354 static inline void ext4_fc_get_tl(struct ext4_fc_tl_mem *tl, u8 *val)
1355 {
1356         struct ext4_fc_tl tl_disk;
1357
1358         memcpy(&tl_disk, val, EXT4_FC_TAG_BASE_LEN);
1359         tl->fc_len = le16_to_cpu(tl_disk.fc_len);
1360         tl->fc_tag = le16_to_cpu(tl_disk.fc_tag);
1361 }
1362
1363 /* Unlink replay function */
1364 static int ext4_fc_replay_unlink(struct super_block *sb,
1365                                  struct ext4_fc_tl_mem *tl, u8 *val)
1366 {
1367         struct inode *inode, *old_parent;
1368         struct qstr entry;
1369         struct dentry_info_args darg;
1370         int ret = 0;
1371
1372         tl_to_darg(&darg, tl, val);
1373
1374         trace_ext4_fc_replay(sb, EXT4_FC_TAG_UNLINK, darg.ino,
1375                         darg.parent_ino, darg.dname_len);
1376
1377         entry.name = darg.dname;
1378         entry.len = darg.dname_len;
1379         inode = ext4_iget(sb, darg.ino, EXT4_IGET_NORMAL);
1380
1381         if (IS_ERR(inode)) {
1382                 ext4_debug("Inode %d not found", darg.ino);
1383                 return 0;
1384         }
1385
1386         old_parent = ext4_iget(sb, darg.parent_ino,
1387                                 EXT4_IGET_NORMAL);
1388         if (IS_ERR(old_parent)) {
1389                 ext4_debug("Dir with inode %d not found", darg.parent_ino);
1390                 iput(inode);
1391                 return 0;
1392         }
1393
1394         ret = __ext4_unlink(old_parent, &entry, inode, NULL);
1395         /* -ENOENT ok coz it might not exist anymore. */
1396         if (ret == -ENOENT)
1397                 ret = 0;
1398         iput(old_parent);
1399         iput(inode);
1400         return ret;
1401 }
1402
1403 static int ext4_fc_replay_link_internal(struct super_block *sb,
1404                                 struct dentry_info_args *darg,
1405                                 struct inode *inode)
1406 {
1407         struct inode *dir = NULL;
1408         struct dentry *dentry_dir = NULL, *dentry_inode = NULL;
1409         struct qstr qstr_dname = QSTR_INIT(darg->dname, darg->dname_len);
1410         int ret = 0;
1411
1412         dir = ext4_iget(sb, darg->parent_ino, EXT4_IGET_NORMAL);
1413         if (IS_ERR(dir)) {
1414                 ext4_debug("Dir with inode %d not found.", darg->parent_ino);
1415                 dir = NULL;
1416                 goto out;
1417         }
1418
1419         dentry_dir = d_obtain_alias(dir);
1420         if (IS_ERR(dentry_dir)) {
1421                 ext4_debug("Failed to obtain dentry");
1422                 dentry_dir = NULL;
1423                 goto out;
1424         }
1425
1426         dentry_inode = d_alloc(dentry_dir, &qstr_dname);
1427         if (!dentry_inode) {
1428                 ext4_debug("Inode dentry not created.");
1429                 ret = -ENOMEM;
1430                 goto out;
1431         }
1432
1433         ret = __ext4_link(dir, inode, dentry_inode);
1434         /*
1435          * It's possible that link already existed since data blocks
1436          * for the dir in question got persisted before we crashed OR
1437          * we replayed this tag and crashed before the entire replay
1438          * could complete.
1439          */
1440         if (ret && ret != -EEXIST) {
1441                 ext4_debug("Failed to link\n");
1442                 goto out;
1443         }
1444
1445         ret = 0;
1446 out:
1447         if (dentry_dir) {
1448                 d_drop(dentry_dir);
1449                 dput(dentry_dir);
1450         } else if (dir) {
1451                 iput(dir);
1452         }
1453         if (dentry_inode) {
1454                 d_drop(dentry_inode);
1455                 dput(dentry_inode);
1456         }
1457
1458         return ret;
1459 }
1460
1461 /* Link replay function */
1462 static int ext4_fc_replay_link(struct super_block *sb,
1463                                struct ext4_fc_tl_mem *tl, u8 *val)
1464 {
1465         struct inode *inode;
1466         struct dentry_info_args darg;
1467         int ret = 0;
1468
1469         tl_to_darg(&darg, tl, val);
1470         trace_ext4_fc_replay(sb, EXT4_FC_TAG_LINK, darg.ino,
1471                         darg.parent_ino, darg.dname_len);
1472
1473         inode = ext4_iget(sb, darg.ino, EXT4_IGET_NORMAL);
1474         if (IS_ERR(inode)) {
1475                 ext4_debug("Inode not found.");
1476                 return 0;
1477         }
1478
1479         ret = ext4_fc_replay_link_internal(sb, &darg, inode);
1480         iput(inode);
1481         return ret;
1482 }
1483
1484 /*
1485  * Record all the modified inodes during replay. We use this later to setup
1486  * block bitmaps correctly.
1487  */
1488 static int ext4_fc_record_modified_inode(struct super_block *sb, int ino)
1489 {
1490         struct ext4_fc_replay_state *state;
1491         int i;
1492
1493         state = &EXT4_SB(sb)->s_fc_replay_state;
1494         for (i = 0; i < state->fc_modified_inodes_used; i++)
1495                 if (state->fc_modified_inodes[i] == ino)
1496                         return 0;
1497         if (state->fc_modified_inodes_used == state->fc_modified_inodes_size) {
1498                 int *fc_modified_inodes;
1499
1500                 fc_modified_inodes = krealloc(state->fc_modified_inodes,
1501                                 sizeof(int) * (state->fc_modified_inodes_size +
1502                                 EXT4_FC_REPLAY_REALLOC_INCREMENT),
1503                                 GFP_KERNEL);
1504                 if (!fc_modified_inodes)
1505                         return -ENOMEM;
1506                 state->fc_modified_inodes = fc_modified_inodes;
1507                 state->fc_modified_inodes_size +=
1508                         EXT4_FC_REPLAY_REALLOC_INCREMENT;
1509         }
1510         state->fc_modified_inodes[state->fc_modified_inodes_used++] = ino;
1511         return 0;
1512 }
1513
1514 /*
1515  * Inode replay function
1516  */
1517 static int ext4_fc_replay_inode(struct super_block *sb,
1518                                 struct ext4_fc_tl_mem *tl, u8 *val)
1519 {
1520         struct ext4_fc_inode fc_inode;
1521         struct ext4_inode *raw_inode;
1522         struct ext4_inode *raw_fc_inode;
1523         struct inode *inode = NULL;
1524         struct ext4_iloc iloc;
1525         int inode_len, ino, ret, tag = tl->fc_tag;
1526         struct ext4_extent_header *eh;
1527         size_t off_gen = offsetof(struct ext4_inode, i_generation);
1528
1529         memcpy(&fc_inode, val, sizeof(fc_inode));
1530
1531         ino = le32_to_cpu(fc_inode.fc_ino);
1532         trace_ext4_fc_replay(sb, tag, ino, 0, 0);
1533
1534         inode = ext4_iget(sb, ino, EXT4_IGET_NORMAL);
1535         if (!IS_ERR(inode)) {
1536                 ext4_ext_clear_bb(inode);
1537                 iput(inode);
1538         }
1539         inode = NULL;
1540
1541         ret = ext4_fc_record_modified_inode(sb, ino);
1542         if (ret)
1543                 goto out;
1544
1545         raw_fc_inode = (struct ext4_inode *)
1546                 (val + offsetof(struct ext4_fc_inode, fc_raw_inode));
1547         ret = ext4_get_fc_inode_loc(sb, ino, &iloc);
1548         if (ret)
1549                 goto out;
1550
1551         inode_len = tl->fc_len - sizeof(struct ext4_fc_inode);
1552         raw_inode = ext4_raw_inode(&iloc);
1553
1554         memcpy(raw_inode, raw_fc_inode, offsetof(struct ext4_inode, i_block));
1555         memcpy((u8 *)raw_inode + off_gen, (u8 *)raw_fc_inode + off_gen,
1556                inode_len - off_gen);
1557         if (le32_to_cpu(raw_inode->i_flags) & EXT4_EXTENTS_FL) {
1558                 eh = (struct ext4_extent_header *)(&raw_inode->i_block[0]);
1559                 if (eh->eh_magic != EXT4_EXT_MAGIC) {
1560                         memset(eh, 0, sizeof(*eh));
1561                         eh->eh_magic = EXT4_EXT_MAGIC;
1562                         eh->eh_max = cpu_to_le16(
1563                                 (sizeof(raw_inode->i_block) -
1564                                  sizeof(struct ext4_extent_header))
1565                                  / sizeof(struct ext4_extent));
1566                 }
1567         } else if (le32_to_cpu(raw_inode->i_flags) & EXT4_INLINE_DATA_FL) {
1568                 memcpy(raw_inode->i_block, raw_fc_inode->i_block,
1569                         sizeof(raw_inode->i_block));
1570         }
1571
1572         /* Immediately update the inode on disk. */
1573         ret = ext4_handle_dirty_metadata(NULL, NULL, iloc.bh);
1574         if (ret)
1575                 goto out;
1576         ret = sync_dirty_buffer(iloc.bh);
1577         if (ret)
1578                 goto out;
1579         ret = ext4_mark_inode_used(sb, ino);
1580         if (ret)
1581                 goto out;
1582
1583         /* Given that we just wrote the inode on disk, this SHOULD succeed. */
1584         inode = ext4_iget(sb, ino, EXT4_IGET_NORMAL);
1585         if (IS_ERR(inode)) {
1586                 ext4_debug("Inode not found.");
1587                 return -EFSCORRUPTED;
1588         }
1589
1590         /*
1591          * Our allocator could have made different decisions than before
1592          * crashing. This should be fixed but until then, we calculate
1593          * the number of blocks the inode.
1594          */
1595         if (!ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA))
1596                 ext4_ext_replay_set_iblocks(inode);
1597
1598         inode->i_generation = le32_to_cpu(ext4_raw_inode(&iloc)->i_generation);
1599         ext4_reset_inode_seed(inode);
1600
1601         ext4_inode_csum_set(inode, ext4_raw_inode(&iloc), EXT4_I(inode));
1602         ret = ext4_handle_dirty_metadata(NULL, NULL, iloc.bh);
1603         sync_dirty_buffer(iloc.bh);
1604         brelse(iloc.bh);
1605 out:
1606         iput(inode);
1607         if (!ret)
1608                 blkdev_issue_flush(sb->s_bdev);
1609
1610         return 0;
1611 }
1612
1613 /*
1614  * Dentry create replay function.
1615  *
1616  * EXT4_FC_TAG_CREAT is preceded by EXT4_FC_TAG_INODE_FULL. Which means, the
1617  * inode for which we are trying to create a dentry here, should already have
1618  * been replayed before we start here.
1619  */
1620 static int ext4_fc_replay_create(struct super_block *sb,
1621                                  struct ext4_fc_tl_mem *tl, u8 *val)
1622 {
1623         int ret = 0;
1624         struct inode *inode = NULL;
1625         struct inode *dir = NULL;
1626         struct dentry_info_args darg;
1627
1628         tl_to_darg(&darg, tl, val);
1629
1630         trace_ext4_fc_replay(sb, EXT4_FC_TAG_CREAT, darg.ino,
1631                         darg.parent_ino, darg.dname_len);
1632
1633         /* This takes care of update group descriptor and other metadata */
1634         ret = ext4_mark_inode_used(sb, darg.ino);
1635         if (ret)
1636                 goto out;
1637
1638         inode = ext4_iget(sb, darg.ino, EXT4_IGET_NORMAL);
1639         if (IS_ERR(inode)) {
1640                 ext4_debug("inode %d not found.", darg.ino);
1641                 inode = NULL;
1642                 ret = -EINVAL;
1643                 goto out;
1644         }
1645
1646         if (S_ISDIR(inode->i_mode)) {
1647                 /*
1648                  * If we are creating a directory, we need to make sure that the
1649                  * dot and dot dot dirents are setup properly.
1650                  */
1651                 dir = ext4_iget(sb, darg.parent_ino, EXT4_IGET_NORMAL);
1652                 if (IS_ERR(dir)) {
1653                         ext4_debug("Dir %d not found.", darg.ino);
1654                         goto out;
1655                 }
1656                 ret = ext4_init_new_dir(NULL, dir, inode);
1657                 iput(dir);
1658                 if (ret) {
1659                         ret = 0;
1660                         goto out;
1661                 }
1662         }
1663         ret = ext4_fc_replay_link_internal(sb, &darg, inode);
1664         if (ret)
1665                 goto out;
1666         set_nlink(inode, 1);
1667         ext4_mark_inode_dirty(NULL, inode);
1668 out:
1669         iput(inode);
1670         return ret;
1671 }
1672
1673 /*
1674  * Record physical disk regions which are in use as per fast commit area,
1675  * and used by inodes during replay phase. Our simple replay phase
1676  * allocator excludes these regions from allocation.
1677  */
1678 int ext4_fc_record_regions(struct super_block *sb, int ino,
1679                 ext4_lblk_t lblk, ext4_fsblk_t pblk, int len, int replay)
1680 {
1681         struct ext4_fc_replay_state *state;
1682         struct ext4_fc_alloc_region *region;
1683
1684         state = &EXT4_SB(sb)->s_fc_replay_state;
1685         /*
1686          * during replay phase, the fc_regions_valid may not same as
1687          * fc_regions_used, update it when do new additions.
1688          */
1689         if (replay && state->fc_regions_used != state->fc_regions_valid)
1690                 state->fc_regions_used = state->fc_regions_valid;
1691         if (state->fc_regions_used == state->fc_regions_size) {
1692                 struct ext4_fc_alloc_region *fc_regions;
1693
1694                 fc_regions = krealloc(state->fc_regions,
1695                                       sizeof(struct ext4_fc_alloc_region) *
1696                                       (state->fc_regions_size +
1697                                        EXT4_FC_REPLAY_REALLOC_INCREMENT),
1698                                       GFP_KERNEL);
1699                 if (!fc_regions)
1700                         return -ENOMEM;
1701                 state->fc_regions_size +=
1702                         EXT4_FC_REPLAY_REALLOC_INCREMENT;
1703                 state->fc_regions = fc_regions;
1704         }
1705         region = &state->fc_regions[state->fc_regions_used++];
1706         region->ino = ino;
1707         region->lblk = lblk;
1708         region->pblk = pblk;
1709         region->len = len;
1710
1711         if (replay)
1712                 state->fc_regions_valid++;
1713
1714         return 0;
1715 }
1716
1717 /* Replay add range tag */
1718 static int ext4_fc_replay_add_range(struct super_block *sb,
1719                                     struct ext4_fc_tl_mem *tl, u8 *val)
1720 {
1721         struct ext4_fc_add_range fc_add_ex;
1722         struct ext4_extent newex, *ex;
1723         struct inode *inode;
1724         ext4_lblk_t start, cur;
1725         int remaining, len;
1726         ext4_fsblk_t start_pblk;
1727         struct ext4_map_blocks map;
1728         struct ext4_ext_path *path = NULL;
1729         int ret;
1730
1731         memcpy(&fc_add_ex, val, sizeof(fc_add_ex));
1732         ex = (struct ext4_extent *)&fc_add_ex.fc_ex;
1733
1734         trace_ext4_fc_replay(sb, EXT4_FC_TAG_ADD_RANGE,
1735                 le32_to_cpu(fc_add_ex.fc_ino), le32_to_cpu(ex->ee_block),
1736                 ext4_ext_get_actual_len(ex));
1737
1738         inode = ext4_iget(sb, le32_to_cpu(fc_add_ex.fc_ino), EXT4_IGET_NORMAL);
1739         if (IS_ERR(inode)) {
1740                 ext4_debug("Inode not found.");
1741                 return 0;
1742         }
1743
1744         ret = ext4_fc_record_modified_inode(sb, inode->i_ino);
1745         if (ret)
1746                 goto out;
1747
1748         start = le32_to_cpu(ex->ee_block);
1749         start_pblk = ext4_ext_pblock(ex);
1750         len = ext4_ext_get_actual_len(ex);
1751
1752         cur = start;
1753         remaining = len;
1754         ext4_debug("ADD_RANGE, lblk %d, pblk %lld, len %d, unwritten %d, inode %ld\n",
1755                   start, start_pblk, len, ext4_ext_is_unwritten(ex),
1756                   inode->i_ino);
1757
1758         while (remaining > 0) {
1759                 map.m_lblk = cur;
1760                 map.m_len = remaining;
1761                 map.m_pblk = 0;
1762                 ret = ext4_map_blocks(NULL, inode, &map, 0);
1763
1764                 if (ret < 0)
1765                         goto out;
1766
1767                 if (ret == 0) {
1768                         /* Range is not mapped */
1769                         path = ext4_find_extent(inode, cur, NULL, 0);
1770                         if (IS_ERR(path))
1771                                 goto out;
1772                         memset(&newex, 0, sizeof(newex));
1773                         newex.ee_block = cpu_to_le32(cur);
1774                         ext4_ext_store_pblock(
1775                                 &newex, start_pblk + cur - start);
1776                         newex.ee_len = cpu_to_le16(map.m_len);
1777                         if (ext4_ext_is_unwritten(ex))
1778                                 ext4_ext_mark_unwritten(&newex);
1779                         down_write(&EXT4_I(inode)->i_data_sem);
1780                         ret = ext4_ext_insert_extent(
1781                                 NULL, inode, &path, &newex, 0);
1782                         up_write((&EXT4_I(inode)->i_data_sem));
1783                         ext4_free_ext_path(path);
1784                         if (ret)
1785                                 goto out;
1786                         goto next;
1787                 }
1788
1789                 if (start_pblk + cur - start != map.m_pblk) {
1790                         /*
1791                          * Logical to physical mapping changed. This can happen
1792                          * if this range was removed and then reallocated to
1793                          * map to new physical blocks during a fast commit.
1794                          */
1795                         ret = ext4_ext_replay_update_ex(inode, cur, map.m_len,
1796                                         ext4_ext_is_unwritten(ex),
1797                                         start_pblk + cur - start);
1798                         if (ret)
1799                                 goto out;
1800                         /*
1801                          * Mark the old blocks as free since they aren't used
1802                          * anymore. We maintain an array of all the modified
1803                          * inodes. In case these blocks are still used at either
1804                          * a different logical range in the same inode or in
1805                          * some different inode, we will mark them as allocated
1806                          * at the end of the FC replay using our array of
1807                          * modified inodes.
1808                          */
1809                         ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, 0);
1810                         goto next;
1811                 }
1812
1813                 /* Range is mapped and needs a state change */
1814                 ext4_debug("Converting from %ld to %d %lld",
1815                                 map.m_flags & EXT4_MAP_UNWRITTEN,
1816                         ext4_ext_is_unwritten(ex), map.m_pblk);
1817                 ret = ext4_ext_replay_update_ex(inode, cur, map.m_len,
1818                                         ext4_ext_is_unwritten(ex), map.m_pblk);
1819                 if (ret)
1820                         goto out;
1821                 /*
1822                  * We may have split the extent tree while toggling the state.
1823                  * Try to shrink the extent tree now.
1824                  */
1825                 ext4_ext_replay_shrink_inode(inode, start + len);
1826 next:
1827                 cur += map.m_len;
1828                 remaining -= map.m_len;
1829         }
1830         ext4_ext_replay_shrink_inode(inode, i_size_read(inode) >>
1831                                         sb->s_blocksize_bits);
1832 out:
1833         iput(inode);
1834         return 0;
1835 }
1836
1837 /* Replay DEL_RANGE tag */
1838 static int
1839 ext4_fc_replay_del_range(struct super_block *sb,
1840                          struct ext4_fc_tl_mem *tl, u8 *val)
1841 {
1842         struct inode *inode;
1843         struct ext4_fc_del_range lrange;
1844         struct ext4_map_blocks map;
1845         ext4_lblk_t cur, remaining;
1846         int ret;
1847
1848         memcpy(&lrange, val, sizeof(lrange));
1849         cur = le32_to_cpu(lrange.fc_lblk);
1850         remaining = le32_to_cpu(lrange.fc_len);
1851
1852         trace_ext4_fc_replay(sb, EXT4_FC_TAG_DEL_RANGE,
1853                 le32_to_cpu(lrange.fc_ino), cur, remaining);
1854
1855         inode = ext4_iget(sb, le32_to_cpu(lrange.fc_ino), EXT4_IGET_NORMAL);
1856         if (IS_ERR(inode)) {
1857                 ext4_debug("Inode %d not found", le32_to_cpu(lrange.fc_ino));
1858                 return 0;
1859         }
1860
1861         ret = ext4_fc_record_modified_inode(sb, inode->i_ino);
1862         if (ret)
1863                 goto out;
1864
1865         ext4_debug("DEL_RANGE, inode %ld, lblk %d, len %d\n",
1866                         inode->i_ino, le32_to_cpu(lrange.fc_lblk),
1867                         le32_to_cpu(lrange.fc_len));
1868         while (remaining > 0) {
1869                 map.m_lblk = cur;
1870                 map.m_len = remaining;
1871
1872                 ret = ext4_map_blocks(NULL, inode, &map, 0);
1873                 if (ret < 0)
1874                         goto out;
1875                 if (ret > 0) {
1876                         remaining -= ret;
1877                         cur += ret;
1878                         ext4_mb_mark_bb(inode->i_sb, map.m_pblk, map.m_len, 0);
1879                 } else {
1880                         remaining -= map.m_len;
1881                         cur += map.m_len;
1882                 }
1883         }
1884
1885         down_write(&EXT4_I(inode)->i_data_sem);
1886         ret = ext4_ext_remove_space(inode, le32_to_cpu(lrange.fc_lblk),
1887                                 le32_to_cpu(lrange.fc_lblk) +
1888                                 le32_to_cpu(lrange.fc_len) - 1);
1889         up_write(&EXT4_I(inode)->i_data_sem);
1890         if (ret)
1891                 goto out;
1892         ext4_ext_replay_shrink_inode(inode,
1893                 i_size_read(inode) >> sb->s_blocksize_bits);
1894         ext4_mark_inode_dirty(NULL, inode);
1895 out:
1896         iput(inode);
1897         return 0;
1898 }
1899
1900 static void ext4_fc_set_bitmaps_and_counters(struct super_block *sb)
1901 {
1902         struct ext4_fc_replay_state *state;
1903         struct inode *inode;
1904         struct ext4_ext_path *path = NULL;
1905         struct ext4_map_blocks map;
1906         int i, ret, j;
1907         ext4_lblk_t cur, end;
1908
1909         state = &EXT4_SB(sb)->s_fc_replay_state;
1910         for (i = 0; i < state->fc_modified_inodes_used; i++) {
1911                 inode = ext4_iget(sb, state->fc_modified_inodes[i],
1912                         EXT4_IGET_NORMAL);
1913                 if (IS_ERR(inode)) {
1914                         ext4_debug("Inode %d not found.",
1915                                 state->fc_modified_inodes[i]);
1916                         continue;
1917                 }
1918                 cur = 0;
1919                 end = EXT_MAX_BLOCKS;
1920                 if (ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA)) {
1921                         iput(inode);
1922                         continue;
1923                 }
1924                 while (cur < end) {
1925                         map.m_lblk = cur;
1926                         map.m_len = end - cur;
1927
1928                         ret = ext4_map_blocks(NULL, inode, &map, 0);
1929                         if (ret < 0)
1930                                 break;
1931
1932                         if (ret > 0) {
1933                                 path = ext4_find_extent(inode, map.m_lblk, NULL, 0);
1934                                 if (!IS_ERR(path)) {
1935                                         for (j = 0; j < path->p_depth; j++)
1936                                                 ext4_mb_mark_bb(inode->i_sb,
1937                                                         path[j].p_block, 1, 1);
1938                                         ext4_free_ext_path(path);
1939                                 }
1940                                 cur += ret;
1941                                 ext4_mb_mark_bb(inode->i_sb, map.m_pblk,
1942                                                         map.m_len, 1);
1943                         } else {
1944                                 cur = cur + (map.m_len ? map.m_len : 1);
1945                         }
1946                 }
1947                 iput(inode);
1948         }
1949 }
1950
1951 /*
1952  * Check if block is in excluded regions for block allocation. The simple
1953  * allocator that runs during replay phase is calls this function to see
1954  * if it is okay to use a block.
1955  */
1956 bool ext4_fc_replay_check_excluded(struct super_block *sb, ext4_fsblk_t blk)
1957 {
1958         int i;
1959         struct ext4_fc_replay_state *state;
1960
1961         state = &EXT4_SB(sb)->s_fc_replay_state;
1962         for (i = 0; i < state->fc_regions_valid; i++) {
1963                 if (state->fc_regions[i].ino == 0 ||
1964                         state->fc_regions[i].len == 0)
1965                         continue;
1966                 if (in_range(blk, state->fc_regions[i].pblk,
1967                                         state->fc_regions[i].len))
1968                         return true;
1969         }
1970         return false;
1971 }
1972
1973 /* Cleanup function called after replay */
1974 void ext4_fc_replay_cleanup(struct super_block *sb)
1975 {
1976         struct ext4_sb_info *sbi = EXT4_SB(sb);
1977
1978         sbi->s_mount_state &= ~EXT4_FC_REPLAY;
1979         kfree(sbi->s_fc_replay_state.fc_regions);
1980         kfree(sbi->s_fc_replay_state.fc_modified_inodes);
1981 }
1982
1983 static bool ext4_fc_value_len_isvalid(struct ext4_sb_info *sbi,
1984                                       int tag, int len)
1985 {
1986         switch (tag) {
1987         case EXT4_FC_TAG_ADD_RANGE:
1988                 return len == sizeof(struct ext4_fc_add_range);
1989         case EXT4_FC_TAG_DEL_RANGE:
1990                 return len == sizeof(struct ext4_fc_del_range);
1991         case EXT4_FC_TAG_CREAT:
1992         case EXT4_FC_TAG_LINK:
1993         case EXT4_FC_TAG_UNLINK:
1994                 len -= sizeof(struct ext4_fc_dentry_info);
1995                 return len >= 1 && len <= EXT4_NAME_LEN;
1996         case EXT4_FC_TAG_INODE:
1997                 len -= sizeof(struct ext4_fc_inode);
1998                 return len >= EXT4_GOOD_OLD_INODE_SIZE &&
1999                         len <= sbi->s_inode_size;
2000         case EXT4_FC_TAG_PAD:
2001                 return true; /* padding can have any length */
2002         case EXT4_FC_TAG_TAIL:
2003                 return len >= sizeof(struct ext4_fc_tail);
2004         case EXT4_FC_TAG_HEAD:
2005                 return len == sizeof(struct ext4_fc_head);
2006         }
2007         return false;
2008 }
2009
2010 /*
2011  * Recovery Scan phase handler
2012  *
2013  * This function is called during the scan phase and is responsible
2014  * for doing following things:
2015  * - Make sure the fast commit area has valid tags for replay
2016  * - Count number of tags that need to be replayed by the replay handler
2017  * - Verify CRC
2018  * - Create a list of excluded blocks for allocation during replay phase
2019  *
2020  * This function returns JBD2_FC_REPLAY_CONTINUE to indicate that SCAN is
2021  * incomplete and JBD2 should send more blocks. It returns JBD2_FC_REPLAY_STOP
2022  * to indicate that scan has finished and JBD2 can now start replay phase.
2023  * It returns a negative error to indicate that there was an error. At the end
2024  * of a successful scan phase, sbi->s_fc_replay_state.fc_replay_num_tags is set
2025  * to indicate the number of tags that need to replayed during the replay phase.
2026  */
2027 static int ext4_fc_replay_scan(journal_t *journal,
2028                                 struct buffer_head *bh, int off,
2029                                 tid_t expected_tid)
2030 {
2031         struct super_block *sb = journal->j_private;
2032         struct ext4_sb_info *sbi = EXT4_SB(sb);
2033         struct ext4_fc_replay_state *state;
2034         int ret = JBD2_FC_REPLAY_CONTINUE;
2035         struct ext4_fc_add_range ext;
2036         struct ext4_fc_tl_mem tl;
2037         struct ext4_fc_tail tail;
2038         __u8 *start, *end, *cur, *val;
2039         struct ext4_fc_head head;
2040         struct ext4_extent *ex;
2041
2042         state = &sbi->s_fc_replay_state;
2043
2044         start = (u8 *)bh->b_data;
2045         end = start + journal->j_blocksize;
2046
2047         if (state->fc_replay_expected_off == 0) {
2048                 state->fc_cur_tag = 0;
2049                 state->fc_replay_num_tags = 0;
2050                 state->fc_crc = 0;
2051                 state->fc_regions = NULL;
2052                 state->fc_regions_valid = state->fc_regions_used =
2053                         state->fc_regions_size = 0;
2054                 /* Check if we can stop early */
2055                 if (le16_to_cpu(((struct ext4_fc_tl *)start)->fc_tag)
2056                         != EXT4_FC_TAG_HEAD)
2057                         return 0;
2058         }
2059
2060         if (off != state->fc_replay_expected_off) {
2061                 ret = -EFSCORRUPTED;
2062                 goto out_err;
2063         }
2064
2065         state->fc_replay_expected_off++;
2066         for (cur = start; cur <= end - EXT4_FC_TAG_BASE_LEN;
2067              cur = cur + EXT4_FC_TAG_BASE_LEN + tl.fc_len) {
2068                 ext4_fc_get_tl(&tl, cur);
2069                 val = cur + EXT4_FC_TAG_BASE_LEN;
2070                 if (tl.fc_len > end - val ||
2071                     !ext4_fc_value_len_isvalid(sbi, tl.fc_tag, tl.fc_len)) {
2072                         ret = state->fc_replay_num_tags ?
2073                                 JBD2_FC_REPLAY_STOP : -ECANCELED;
2074                         goto out_err;
2075                 }
2076                 ext4_debug("Scan phase, tag:%s, blk %lld\n",
2077                            tag2str(tl.fc_tag), bh->b_blocknr);
2078                 switch (tl.fc_tag) {
2079                 case EXT4_FC_TAG_ADD_RANGE:
2080                         memcpy(&ext, val, sizeof(ext));
2081                         ex = (struct ext4_extent *)&ext.fc_ex;
2082                         ret = ext4_fc_record_regions(sb,
2083                                 le32_to_cpu(ext.fc_ino),
2084                                 le32_to_cpu(ex->ee_block), ext4_ext_pblock(ex),
2085                                 ext4_ext_get_actual_len(ex), 0);
2086                         if (ret < 0)
2087                                 break;
2088                         ret = JBD2_FC_REPLAY_CONTINUE;
2089                         fallthrough;
2090                 case EXT4_FC_TAG_DEL_RANGE:
2091                 case EXT4_FC_TAG_LINK:
2092                 case EXT4_FC_TAG_UNLINK:
2093                 case EXT4_FC_TAG_CREAT:
2094                 case EXT4_FC_TAG_INODE:
2095                 case EXT4_FC_TAG_PAD:
2096                         state->fc_cur_tag++;
2097                         state->fc_crc = ext4_chksum(sbi, state->fc_crc, cur,
2098                                 EXT4_FC_TAG_BASE_LEN + tl.fc_len);
2099                         break;
2100                 case EXT4_FC_TAG_TAIL:
2101                         state->fc_cur_tag++;
2102                         memcpy(&tail, val, sizeof(tail));
2103                         state->fc_crc = ext4_chksum(sbi, state->fc_crc, cur,
2104                                                 EXT4_FC_TAG_BASE_LEN +
2105                                                 offsetof(struct ext4_fc_tail,
2106                                                 fc_crc));
2107                         if (le32_to_cpu(tail.fc_tid) == expected_tid &&
2108                                 le32_to_cpu(tail.fc_crc) == state->fc_crc) {
2109                                 state->fc_replay_num_tags = state->fc_cur_tag;
2110                                 state->fc_regions_valid =
2111                                         state->fc_regions_used;
2112                         } else {
2113                                 ret = state->fc_replay_num_tags ?
2114                                         JBD2_FC_REPLAY_STOP : -EFSBADCRC;
2115                         }
2116                         state->fc_crc = 0;
2117                         break;
2118                 case EXT4_FC_TAG_HEAD:
2119                         memcpy(&head, val, sizeof(head));
2120                         if (le32_to_cpu(head.fc_features) &
2121                                 ~EXT4_FC_SUPPORTED_FEATURES) {
2122                                 ret = -EOPNOTSUPP;
2123                                 break;
2124                         }
2125                         if (le32_to_cpu(head.fc_tid) != expected_tid) {
2126                                 ret = JBD2_FC_REPLAY_STOP;
2127                                 break;
2128                         }
2129                         state->fc_cur_tag++;
2130                         state->fc_crc = ext4_chksum(sbi, state->fc_crc, cur,
2131                                 EXT4_FC_TAG_BASE_LEN + tl.fc_len);
2132                         break;
2133                 default:
2134                         ret = state->fc_replay_num_tags ?
2135                                 JBD2_FC_REPLAY_STOP : -ECANCELED;
2136                 }
2137                 if (ret < 0 || ret == JBD2_FC_REPLAY_STOP)
2138                         break;
2139         }
2140
2141 out_err:
2142         trace_ext4_fc_replay_scan(sb, ret, off);
2143         return ret;
2144 }
2145
2146 /*
2147  * Main recovery path entry point.
2148  * The meaning of return codes is similar as above.
2149  */
2150 static int ext4_fc_replay(journal_t *journal, struct buffer_head *bh,
2151                                 enum passtype pass, int off, tid_t expected_tid)
2152 {
2153         struct super_block *sb = journal->j_private;
2154         struct ext4_sb_info *sbi = EXT4_SB(sb);
2155         struct ext4_fc_tl_mem tl;
2156         __u8 *start, *end, *cur, *val;
2157         int ret = JBD2_FC_REPLAY_CONTINUE;
2158         struct ext4_fc_replay_state *state = &sbi->s_fc_replay_state;
2159         struct ext4_fc_tail tail;
2160
2161         if (pass == PASS_SCAN) {
2162                 state->fc_current_pass = PASS_SCAN;
2163                 return ext4_fc_replay_scan(journal, bh, off, expected_tid);
2164         }
2165
2166         if (state->fc_current_pass != pass) {
2167                 state->fc_current_pass = pass;
2168                 sbi->s_mount_state |= EXT4_FC_REPLAY;
2169         }
2170         if (!sbi->s_fc_replay_state.fc_replay_num_tags) {
2171                 ext4_debug("Replay stops\n");
2172                 ext4_fc_set_bitmaps_and_counters(sb);
2173                 return 0;
2174         }
2175
2176 #ifdef CONFIG_EXT4_DEBUG
2177         if (sbi->s_fc_debug_max_replay && off >= sbi->s_fc_debug_max_replay) {
2178                 pr_warn("Dropping fc block %d because max_replay set\n", off);
2179                 return JBD2_FC_REPLAY_STOP;
2180         }
2181 #endif
2182
2183         start = (u8 *)bh->b_data;
2184         end = start + journal->j_blocksize;
2185
2186         for (cur = start; cur <= end - EXT4_FC_TAG_BASE_LEN;
2187              cur = cur + EXT4_FC_TAG_BASE_LEN + tl.fc_len) {
2188                 ext4_fc_get_tl(&tl, cur);
2189                 val = cur + EXT4_FC_TAG_BASE_LEN;
2190
2191                 if (state->fc_replay_num_tags == 0) {
2192                         ret = JBD2_FC_REPLAY_STOP;
2193                         ext4_fc_set_bitmaps_and_counters(sb);
2194                         break;
2195                 }
2196
2197                 ext4_debug("Replay phase, tag:%s\n", tag2str(tl.fc_tag));
2198                 state->fc_replay_num_tags--;
2199                 switch (tl.fc_tag) {
2200                 case EXT4_FC_TAG_LINK:
2201                         ret = ext4_fc_replay_link(sb, &tl, val);
2202                         break;
2203                 case EXT4_FC_TAG_UNLINK:
2204                         ret = ext4_fc_replay_unlink(sb, &tl, val);
2205                         break;
2206                 case EXT4_FC_TAG_ADD_RANGE:
2207                         ret = ext4_fc_replay_add_range(sb, &tl, val);
2208                         break;
2209                 case EXT4_FC_TAG_CREAT:
2210                         ret = ext4_fc_replay_create(sb, &tl, val);
2211                         break;
2212                 case EXT4_FC_TAG_DEL_RANGE:
2213                         ret = ext4_fc_replay_del_range(sb, &tl, val);
2214                         break;
2215                 case EXT4_FC_TAG_INODE:
2216                         ret = ext4_fc_replay_inode(sb, &tl, val);
2217                         break;
2218                 case EXT4_FC_TAG_PAD:
2219                         trace_ext4_fc_replay(sb, EXT4_FC_TAG_PAD, 0,
2220                                              tl.fc_len, 0);
2221                         break;
2222                 case EXT4_FC_TAG_TAIL:
2223                         trace_ext4_fc_replay(sb, EXT4_FC_TAG_TAIL,
2224                                              0, tl.fc_len, 0);
2225                         memcpy(&tail, val, sizeof(tail));
2226                         WARN_ON(le32_to_cpu(tail.fc_tid) != expected_tid);
2227                         break;
2228                 case EXT4_FC_TAG_HEAD:
2229                         break;
2230                 default:
2231                         trace_ext4_fc_replay(sb, tl.fc_tag, 0, tl.fc_len, 0);
2232                         ret = -ECANCELED;
2233                         break;
2234                 }
2235                 if (ret < 0)
2236                         break;
2237                 ret = JBD2_FC_REPLAY_CONTINUE;
2238         }
2239         return ret;
2240 }
2241
2242 void ext4_fc_init(struct super_block *sb, journal_t *journal)
2243 {
2244         /*
2245          * We set replay callback even if fast commit disabled because we may
2246          * could still have fast commit blocks that need to be replayed even if
2247          * fast commit has now been turned off.
2248          */
2249         journal->j_fc_replay_callback = ext4_fc_replay;
2250         if (!test_opt2(sb, JOURNAL_FAST_COMMIT))
2251                 return;
2252         journal->j_fc_cleanup_callback = ext4_fc_cleanup;
2253 }
2254
2255 static const char * const fc_ineligible_reasons[] = {
2256         [EXT4_FC_REASON_XATTR] = "Extended attributes changed",
2257         [EXT4_FC_REASON_CROSS_RENAME] = "Cross rename",
2258         [EXT4_FC_REASON_JOURNAL_FLAG_CHANGE] = "Journal flag changed",
2259         [EXT4_FC_REASON_NOMEM] = "Insufficient memory",
2260         [EXT4_FC_REASON_SWAP_BOOT] = "Swap boot",
2261         [EXT4_FC_REASON_RESIZE] = "Resize",
2262         [EXT4_FC_REASON_RENAME_DIR] = "Dir renamed",
2263         [EXT4_FC_REASON_FALLOC_RANGE] = "Falloc range op",
2264         [EXT4_FC_REASON_INODE_JOURNAL_DATA] = "Data journalling",
2265         [EXT4_FC_REASON_ENCRYPTED_FILENAME] = "Encrypted filename",
2266 };
2267
2268 int ext4_fc_info_show(struct seq_file *seq, void *v)
2269 {
2270         struct ext4_sb_info *sbi = EXT4_SB((struct super_block *)seq->private);
2271         struct ext4_fc_stats *stats = &sbi->s_fc_stats;
2272         int i;
2273
2274         if (v != SEQ_START_TOKEN)
2275                 return 0;
2276
2277         seq_printf(seq,
2278                 "fc stats:\n%ld commits\n%ld ineligible\n%ld numblks\n%lluus avg_commit_time\n",
2279                    stats->fc_num_commits, stats->fc_ineligible_commits,
2280                    stats->fc_numblks,
2281                    div_u64(stats->s_fc_avg_commit_time, 1000));
2282         seq_puts(seq, "Ineligible reasons:\n");
2283         for (i = 0; i < EXT4_FC_REASON_MAX; i++)
2284                 seq_printf(seq, "\"%s\":\t%d\n", fc_ineligible_reasons[i],
2285                         stats->fc_ineligible_reason_count[i]);
2286
2287         return 0;
2288 }
2289
2290 int __init ext4_fc_init_dentry_cache(void)
2291 {
2292         ext4_fc_dentry_cachep = KMEM_CACHE(ext4_fc_dentry_update,
2293                                            SLAB_RECLAIM_ACCOUNT);
2294
2295         if (ext4_fc_dentry_cachep == NULL)
2296                 return -ENOMEM;
2297
2298         return 0;
2299 }
2300
2301 void ext4_fc_destroy_dentry_cache(void)
2302 {
2303         kmem_cache_destroy(ext4_fc_dentry_cachep);
2304 }