Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756417AbaAIOWe (ORCPT ); Thu, 9 Jan 2014 09:22:34 -0500 Received: from mail-qc0-f177.google.com ([209.85.216.177]:54991 "EHLO mail-qc0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754908AbaAIOUQ (ORCPT ); Thu, 9 Jan 2014 09:20:16 -0500 From: Jeff Layton To: linux-fsdevel@vger.kernel.org Cc: nfs-ganesha-devel@lists.sourceforge.net, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 13/14] locks: skip deadlock detection on FL_FILE_PVT locks Date: Thu, 9 Jan 2014 09:19:46 -0500 Message-Id: <1389277187-18211-14-git-send-email-jlayton@redhat.com> X-Mailer: git-send-email 1.8.4.2 In-Reply-To: <1389277187-18211-1-git-send-email-jlayton@redhat.com> References: <1389277187-18211-1-git-send-email-jlayton@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/