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authorDave Chinner <dchinner@redhat.com>2010-12-23 11:57:13 +1100
committerDave Chinner <david@fromorbit.com>2010-12-23 11:57:13 +1100
commitdcfcf20512cb517ac18b9433b676183fa1257911 (patch)
treefd5551251e63f47dbb804e36cfd4cb3f15f5c322 /fs/xfs/xfs_iget.c
parent489a150f6454e2cd93d9e0ee6d7c5a361844f62a (diff)
xfs: provide a inode iolock lockdep class
The XFS iolock needs to be re-initialised to a new lock class before it enters reclaim to prevent lockdep false positives. Unfortunately, this is not sufficient protection as inodes in the XFS_IRECLAIMABLE state can be recycled and not re-initialised before being reused. We need to re-initialise the lock state when transfering out of XFS_IRECLAIMABLE state to XFS_INEW, but we need to keep the same class as if the inode was just allocated. Hence we need a specific lockdep class variable for the iolock so that both initialisations use the same class. While there, add a specific class for inodes in the reclaim state so that it is easy to tell from lockdep reports what state the inode was in that generated the report. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/xfs/xfs_iget.c')
-rw-r--r--fs/xfs/xfs_iget.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c
index 0cdd26932d8..cdb1c2505fc 100644
--- a/fs/xfs/xfs_iget.c
+++ b/fs/xfs/xfs_iget.c
@@ -43,6 +43,17 @@
/*
+ * Define xfs inode iolock lockdep classes. We need to ensure that all active
+ * inodes are considered the same for lockdep purposes, including inodes that
+ * are recycled through the XFS_IRECLAIMABLE state. This is the the only way to
+ * guarantee the locks are considered the same when there are multiple lock
+ * initialisation siteѕ. Also, define a reclaimable inode class so it is
+ * obvious in lockdep reports which class the report is against.
+ */
+static struct lock_class_key xfs_iolock_active;
+struct lock_class_key xfs_iolock_reclaimable;
+
+/*
* Allocate and initialise an xfs_inode.
*/
STATIC struct xfs_inode *
@@ -71,6 +82,8 @@ xfs_inode_alloc(
ASSERT(completion_done(&ip->i_flush));
mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
+ lockdep_set_class_and_name(&ip->i_iolock.mr_lock,
+ &xfs_iolock_active, "xfs_iolock_active");
/* initialise the xfs inode */
ip->i_ino = ino;
@@ -218,6 +231,12 @@ xfs_iget_cache_hit(
ip->i_flags |= XFS_INEW;
__xfs_inode_clear_reclaim_tag(mp, pag, ip);
inode->i_state = I_NEW;
+
+ ASSERT(!rwsem_is_locked(&ip->i_iolock.mr_lock));
+ mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
+ lockdep_set_class_and_name(&ip->i_iolock.mr_lock,
+ &xfs_iolock_active, "xfs_iolock_active");
+
spin_unlock(&ip->i_flags_lock);
write_unlock(&pag->pag_ici_lock);
} else {