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authorZhaolei <zhaolei@cn.fujitsu.com>2015-08-06 22:39:36 +0800
committerChris Mason <clm@fb.com>2015-08-09 07:07:14 -0700
commit166f66d0bc94a14ec4bc6ee6ab079532df4a8d9e (patch)
tree276972a024d58650bcf98113bfd264b9ff1c3fb5 /fs/btrfs
parent9ed0dea09fc5e8cb1926c15fc986a46a2db43da6 (diff)
downloadlinux-166f66d0bc94a14ec4bc6ee6ab079532df4a8d9e.tar.bz2
btrfs: Add WARN_ON() for double lock in btrfs_tree_lock()
When a task trying to double lock a extent buffer, there are no lockdep warning about it because this lock may be in "blocking_lock" state, and make us hard to debug. This patch add a WARN_ON() for above condition, it can not report all deadlock cases(as lock between tasks), but at least helps us some. Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/locking.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index f8229ef1b46d..d7e6baf1b205 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -241,6 +241,7 @@ void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb)
*/
void btrfs_tree_lock(struct extent_buffer *eb)
{
+ WARN_ON(eb->lock_owner == current->pid);
again:
wait_event(eb->read_lock_wq, atomic_read(&eb->blocking_readers) == 0);
wait_event(eb->write_lock_wq, atomic_read(&eb->blocking_writers) == 0);