From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934829Ab3DGXbM (ORCPT ); Sun, 7 Apr 2013 19:31:12 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:46764 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934583Ab3DGXbI (ORCPT ); Sun, 7 Apr 2013 19:31:08 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Artem Bityutskiy" , "Mark Jackson" Date: Sun, 07 Apr 2013 23:45:42 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [03/74] UBIFS: make space fixup work in the remount case In-Reply-To: X-SA-Exim-Connect-IP: 2001:470:1f08:1539:b4b3:7e2a:e2d0:3478 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.43-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Artem Bityutskiy commit 67e753ca41782913d805ff4a8a2b0f60b26b7915 upstream. The UBIFS space fixup is a useful feature which allows to fixup the "broken" flash space at the time of the first mount. The "broken" space is usually the result of using a "dumb" industrial flasher which is not able to skip empty NAND pages and just writes all 0xFFs to the empty space, which has grave side-effects for UBIFS when UBIFS trise to write useful data to those empty pages. The fix-up feature works roughly like this: 1. mkfs.ubifs sets the fixup flag in UBIFS superblock when creating the image (see -F option) 2. when the file-system is mounted for the first time, UBIFS notices the fixup flag and re-writes the entire media atomically, which may take really a lot of time. 3. UBIFS clears the fixup flag in the superblock. This works fine when the file system is mounted R/W for the very first time. But it did not really work in the case when we first mount the file-system R/O, and then re-mount R/W. The reason was that we started the fixup procedure too late, which we cannot really do because we have to fixup the space before it starts being used. Signed-off-by: Artem Bityutskiy Reported-by: Mark Jackson Signed-off-by: Ben Hutchings --- fs/ubifs/super.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) --- a/fs/ubifs/super.c +++ b/fs/ubifs/super.c @@ -1583,6 +1583,12 @@ static int ubifs_remount_rw(struct ubifs c->remounting_rw = 1; c->ro_mount = 0; + if (c->space_fixup) { + err = ubifs_fixup_free_space(c); + if (err) + return err; + } + err = check_free_space(c); if (err) goto out; @@ -1699,12 +1705,6 @@ static int ubifs_remount_rw(struct ubifs err = dbg_check_space_info(c); } - if (c->space_fixup) { - err = ubifs_fixup_free_space(c); - if (err) - goto out; - } - mutex_unlock(&c->umount_mutex); return err;