diff options
| author | Dave Chinner <dchinner@redhat.com> | 2014-02-27 16:51:39 +1100 |
|---|---|---|
| committer | Dave Chinner <david@fromorbit.com> | 2014-02-27 16:51:39 +1100 |
| commit | 93a8614e3a4dccd526aca34e892ac0b27f64b506 (patch) | |
| tree | 494837b23f0f9c4a867537e684903b7f135d9ee4 /fs/xfs/xfs_iops.c | |
| parent | a1358aa3d39251c16c6d8b20945e40bdfc2aad68 (diff) | |
xfs: fix directory inode iolock lockdep false positive
The change to add the IO lock to protect the directory extent map
during readdir operations has cause lockdep to have a heart attack
as it now sees a different locking order on inodes w.r.t. the
mmap_sem because readdir has a different ordering to write().
Add a new lockdep class for directory inodes to avoid this false
positive.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/xfs/xfs_iops.c')
| -rw-r--r-- | fs/xfs/xfs_iops.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c index f35d5c953ff9..234e84387ec5 100644 --- a/fs/xfs/xfs_iops.c +++ b/fs/xfs/xfs_iops.c @@ -48,6 +48,18 @@ #include <linux/fiemap.h> #include <linux/slab.h> +/* + * Directories have different lock order w.r.t. mmap_sem compared to regular + * files. This is due to readdir potentially triggering page faults on a user + * buffer inside filldir(), and this happens with the ilock on the directory + * held. For regular files, the lock order is the other way around - the + * mmap_sem is taken during the page fault, and then we lock the ilock to do + * block mapping. Hence we need a different class for the directory ilock so + * that lockdep can tell them apart. + */ +static struct lock_class_key xfs_nondir_ilock_class; +static struct lock_class_key xfs_dir_ilock_class; + static int xfs_initxattrs( struct inode *inode, @@ -1191,6 +1203,7 @@ xfs_setup_inode( xfs_diflags_to_iflags(inode, ip); ip->d_ops = ip->i_mount->m_nondir_inode_ops; + lockdep_set_class(&ip->i_lock.mr_lock, &xfs_nondir_ilock_class); switch (inode->i_mode & S_IFMT) { case S_IFREG: inode->i_op = &xfs_inode_operations; @@ -1198,6 +1211,7 @@ xfs_setup_inode( inode->i_mapping->a_ops = &xfs_address_space_operations; break; case S_IFDIR: + lockdep_set_class(&ip->i_lock.mr_lock, &xfs_dir_ilock_class); if (xfs_sb_version_hasasciici(&XFS_M(inode->i_sb)->m_sb)) inode->i_op = &xfs_dir_ci_inode_operations; else |