diff options
| -rw-r--r-- | fs/btrfs/tree-log.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index a2bae5c230e1..7dd7552f53a4 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -4823,6 +4823,50 @@ static int log_conflicting_inodes(struct btrfs_trans_handle *trans, continue; } /* + * If the inode was already logged skip it - otherwise we can + * hit an infinite loop. Example: + * + * From the commit root (previous transaction) we have the + * following inodes: + * + * inode 257 a directory + * inode 258 with references "zz" and "zz_link" on inode 257 + * inode 259 with reference "a" on inode 257 + * + * And in the current (uncommitted) transaction we have: + * + * inode 257 a directory, unchanged + * inode 258 with references "a" and "a2" on inode 257 + * inode 259 with reference "zz_link" on inode 257 + * inode 261 with reference "zz" on inode 257 + * + * When logging inode 261 the following infinite loop could + * happen if we don't skip already logged inodes: + * + * - we detect inode 258 as a conflicting inode, with inode 261 + * on reference "zz", and log it; + * + * - we detect inode 259 as a conflicting inode, with inode 258 + * on reference "a", and log it; + * + * - we detect inode 258 as a conflicting inode, with inode 259 + * on reference "zz_link", and log it - again! After this we + * repeat the above steps forever. + */ + spin_lock(&BTRFS_I(inode)->lock); + /* + * Check the inode's logged_trans only instead of + * btrfs_inode_in_log(). This is because the last_log_commit of + * the inode is not updated when we only log that it exists and + * and it has the full sync bit set (see btrfs_log_inode()). + */ + if (BTRFS_I(inode)->logged_trans == trans->transid) { + spin_unlock(&BTRFS_I(inode)->lock); + btrfs_add_delayed_iput(inode); + continue; + } + spin_unlock(&BTRFS_I(inode)->lock); + /* * We are safe logging the other inode without acquiring its * lock as long as we log with the LOG_INODE_EXISTS mode. We * are safe against concurrent renames of the other inode as |