locks: skip deadlock detection on FL_FILE_PVT locks (57b65325) · Commits · 戴 / test

fs/locks.c

+17 −2

Original line number	Diff line number	Diff line
		@@ -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 +757,16 @@ 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, the deadlock detection below can't reasonably work well. Just
		* skip it for those.
		*
		* In principle, we could do a more limited deadlock detection on FL_FILE_PVT
		* locks that just checks for the case where two tasks are attempting to
		* upgrade from read to write locks on the same inode.
		*/

		#define MAX_DEADLK_ITERATIONS 10
		@@ -781,6 +789,13 @@ static int posix_locks_deadlock(struct file_lock *caller_fl,
		{
		int i = 0;

		/*
		* This deadlock detector can't reasonably detect deadlocks with
		* FL_FILE_PVT locks, since they aren't owned by a process, per-se.
		*/
		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;