summaryrefslogtreecommitdiff
path: root/fs/xfs
diff options
context:
space:
mode:
authorDave Chinner <dchinner@redhat.com>2014-02-27 16:51:39 +1100
committerDave Chinner <david@fromorbit.com>2014-02-27 16:51:39 +1100
commit93a8614e3a4dccd526aca34e892ac0b27f64b506 (patch)
tree494837b23f0f9c4a867537e684903b7f135d9ee4 /fs/xfs
parenta1358aa3d39251c16c6d8b20945e40bdfc2aad68 (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')
-rw-r--r--fs/xfs/xfs_iops.c14
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