diff options
Diffstat (limited to 'fs/btrfs/inode.c')
| -rw-r--r-- | fs/btrfs/inode.c | 35 |
1 files changed, 34 insertions, 1 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index f924d9a62700..237da012f7d0 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -3658,6 +3658,35 @@ cache_index: set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags); + /* + * We don't persist the id of the transaction where an unlink operation + * against the inode was last made. So here we assume the inode might + * have been evicted, and therefore the exact value of last_unlink_trans + * lost, and set it to last_trans to avoid metadata inconsistencies + * between the inode and its parent if the inode is fsync'ed and the log + * replayed. For example, in the scenario: + * + * touch mydir/foo + * ln mydir/foo mydir/bar + * sync + * unlink mydir/bar + * echo 2 > /proc/sys/vm/drop_caches # evicts inode + * xfs_io -c fsync mydir/foo + * <power failure> + * mount fs, triggers fsync log replay + * + * We must make sure that when we fsync our inode foo we also log its + * parent inode, otherwise after log replay the parent still has the + * dentry with the "bar" name but our inode foo has a link count of 1 + * and doesn't have an inode ref with the name "bar" anymore. + * + * Setting last_unlink_trans to last_trans is a pessimistic approach, + * but it guarantees correctness at the expense of ocassional full + * transaction commits on fsync if our inode is a directory, or if our + * inode is not a directory, logging its parent unnecessarily. + */ + BTRFS_I(inode)->last_unlink_trans = BTRFS_I(inode)->last_trans; + path->slots[0]++; if (inode->i_nlink != 1 || path->slots[0] >= btrfs_header_nritems(leaf)) @@ -7958,7 +7987,11 @@ out: static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev, u64 first_sector, gfp_t gfp_flags) { - return btrfs_bio_alloc(bdev, first_sector, BIO_MAX_PAGES, gfp_flags); + struct bio *bio; + bio = btrfs_bio_alloc(bdev, first_sector, BIO_MAX_PAGES, gfp_flags); + if (bio) + bio_associate_current(bio); + return bio; } static inline int btrfs_lookup_and_bind_dio_csum(struct btrfs_root *root, |