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@xxxxxxxxxxxxxx>
---
fs/btrfs/locking.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index f8229ef..d7e6baf 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);
--
1.8.5.1
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