summaryrefslogtreecommitdiffstats
path: root/fs/ext4/ext4.h
diff options
context:
space:
mode:
authorTheodore Ts'o <tytso@mit.edu>2016-04-01 01:31:28 -0400
committerTheodore Ts'o <tytso@mit.edu>2016-04-01 01:31:28 -0400
commitdaf647d2dd58cec59570d7698a45b98e580f2076 (patch)
tree91d950bb640b3e16c36bf09265d46bd07dd0fba0 /fs/ext4/ext4.h
parent1028b55bafb7611dda1d8fed2aeca16a436b7dff (diff)
downloadop-kernel-dev-daf647d2dd58cec59570d7698a45b98e580f2076.zip
op-kernel-dev-daf647d2dd58cec59570d7698a45b98e580f2076.tar.gz
ext4: add lockdep annotations for i_data_sem
With the internal Quota feature, mke2fs creates empty quota inodes and quota usage tracking is enabled as soon as the file system is mounted. Since quotacheck is no longer preallocating all of the blocks in the quota inode that are likely needed to be written to, we are now seeing a lockdep false positive caused by needing to allocate a quota block from inside ext4_map_blocks(), while holding i_data_sem for a data inode. This results in this complaint: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ei->i_data_sem); lock(&s->s_dquot.dqio_mutex); lock(&ei->i_data_sem); lock(&s->s_dquot.dqio_mutex); Google-Bug-Id: 27907753 Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
Diffstat (limited to 'fs/ext4/ext4.h')
-rw-r--r--fs/ext4/ext4.h23
1 files changed, 23 insertions, 0 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 7e4e3e9..6a857af0 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -912,6 +912,29 @@ do { \
#include "extents_status.h"
/*
+ * Lock subclasses for i_data_sem in the ext4_inode_info structure.
+ *
+ * These are needed to avoid lockdep false positives when we need to
+ * allocate blocks to the quota inode during ext4_map_blocks(), while
+ * holding i_data_sem for a normal (non-quota) inode. Since we don't
+ * do quota tracking for the quota inode, this avoids deadlock (as
+ * well as infinite recursion, since it isn't turtles all the way
+ * down...)
+ *
+ * I_DATA_SEM_NORMAL - Used for most inodes
+ * I_DATA_SEM_OTHER - Used by move_inode.c for the second normal inode
+ * where the second inode has larger inode number
+ * than the first
+ * I_DATA_SEM_QUOTA - Used for quota inodes only
+ */
+enum {
+ I_DATA_SEM_NORMAL = 0,
+ I_DATA_SEM_OTHER,
+ I_DATA_SEM_QUOTA,
+};
+
+
+/*
* fourth extended file system inode data in memory
*/
struct ext4_inode_info {
OpenPOWER on IntegriCloud