Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933407Ab0HLAKJ (ORCPT ); Wed, 11 Aug 2010 20:10:09 -0400 Received: from kroah.org ([198.145.64.141]:48010 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933318Ab0HLAJJ (ORCPT ); Wed, 11 Aug 2010 20:09:09 -0400 X-Mailbox-Line: From gregkh@clark.site Wed Aug 11 17:06:18 2010 Message-Id: <20100812000618.864595126@clark.site> User-Agent: quilt/0.48-11.2 Date: Wed, 11 Aug 2010 17:06:22 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Eric Sandeen , "Theodore Tso" Subject: [67/67] ext4: fix freeze deadlock under IO In-Reply-To: <20100812000641.GA6348@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2078 Lines: 59 2.6.35-stable review patch. If anyone has any objections, please let us know. ------------------ From: Eric Sandeen commit 437f88cc031ffe7f37f3e705367f4fe1f4be8b0f upstream. Commit 6b0310fbf087ad6 caused a regression resulting in deadlocks when freezing a filesystem which had active IO; the vfs_check_frozen level (SB_FREEZE_WRITE) did not let the freeze-related IO syncing through. Duh. Changing the test to FREEZE_TRANS should let the normal freeze syncing get through the fs, but still block any transactions from starting once the fs is completely frozen. I tested this by running fsstress in the background while periodically snapshotting the fs and running fsck on the result. I ran into occasional deadlocks, but different ones. I think this is a fine fix for the problem at hand, and the other deadlocky things will need more investigation. Reported-by: Phillip Susi Signed-off-by: Eric Sandeen Signed-off-by: "Theodore Ts'o" Signed-off-by: Greg Kroah-Hartman --- fs/ext4/super.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -241,7 +241,7 @@ handle_t *ext4_journal_start_sb(struct s if (sb->s_flags & MS_RDONLY) return ERR_PTR(-EROFS); - vfs_check_frozen(sb, SB_FREEZE_WRITE); + vfs_check_frozen(sb, SB_FREEZE_TRANS); /* Special case here: if the journal has aborted behind our * backs (eg. EIO in the commit thread), then we still need to * take the FS itself readonly cleanly. */ @@ -3491,7 +3491,7 @@ int ext4_force_commit(struct super_block journal = EXT4_SB(sb)->s_journal; if (journal) { - vfs_check_frozen(sb, SB_FREEZE_WRITE); + vfs_check_frozen(sb, SB_FREEZE_TRANS); ret = ext4_journal_force_commit(journal); } -- 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/