It's not really feasible to do deadlock detection with FL_FILE_PVT
locks since they aren't owned by a single task, per-se. Deadlock
detection also tends to be rather expensive so just skip it for
these sorts of locks.
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/locks.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/fs/locks.c b/fs/locks.c
index f8cd6d7..94bcca6 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -564,7 +564,7 @@ static void __locks_insert_block(struct file_lock *blocker,
BUG_ON(!list_empty(&waiter->fl_block));
waiter->fl_next = blocker;
list_add_tail(&waiter->fl_block, &blocker->fl_block);
- if (IS_POSIX(blocker))
+ if (IS_POSIX(blocker) && !IS_FILE_PVT(blocker))
locks_insert_global_blocked(waiter);
}
@@ -757,8 +757,12 @@ EXPORT_SYMBOL(posix_test_lock);
* Note: the above assumption may not be true when handling lock
* requests from a broken NFS client. It may also fail in the presence
* of tasks (such as posix threads) sharing the same open file table.
- *
* To handle those cases, we just bail out after a few iterations.
+ *
+ * For FL_FILE_PVT locks, the owner is the filp, not the files_struct.
+ * Because the owner is not even nominally tied to a thread of
+ * execution, deadlock detection can't reasonably work well. Just skip
+ * it for those.
*/
#define MAX_DEADLK_ITERATIONS 10
@@ -781,6 +785,10 @@ static int posix_locks_deadlock(struct file_lock *caller_fl,
{
int i = 0;
+ /* Can't reasonably detect deadlocks with FL_FILE_PVT locks */
+ if (IS_FILE_PVT(caller_fl))
+ return 0;
+
while ((block_fl = what_owner_is_waiting_for(block_fl))) {
if (i++ > MAX_DEADLK_ITERATIONS)
return 0;
--
1.8.4.2
--
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