From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755708Ab2LCOsc (ORCPT ); Mon, 3 Dec 2012 09:48:32 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43774 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932240Ab2LCOgW (ORCPT ); Mon, 3 Dec 2012 09:36:22 -0500 Message-Id: <20121203143156.032932304@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 03 Dec 2012 14:32:47 +0000 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Jan Kara Subject: [ 61/89] reiserfs: Fix lock ordering during remount In-Reply-To: <20121203143146.549859007@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 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-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit 3bb3e1fc47aca554e7e2cc4deeddc24750987ac2 upstream. When remounting reiserfs dquot_suspend() or dquot_resume() can be called. These functions take dqonoff_mutex which ranks above write lock so we have to drop it before calling into quota code. Signed-off-by: Jan Kara [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- fs/reiserfs/super.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-) --- a/fs/reiserfs/super.c +++ b/fs/reiserfs/super.c @@ -1207,7 +1207,7 @@ static int reiserfs_remount(struct super kfree(qf_names[i]); #endif err = -EINVAL; - goto out_err; + goto out_unlock; } #ifdef CONFIG_QUOTA handle_quota_files(s, qf_names, &qfmt); @@ -1250,7 +1250,7 @@ static int reiserfs_remount(struct super if (blocks) { err = reiserfs_resize(s, blocks); if (err != 0) - goto out_err; + goto out_unlock; } if (*mount_flags & MS_RDONLY) { @@ -1260,9 +1260,15 @@ static int reiserfs_remount(struct super /* it is read-only already */ goto out_ok; + /* + * Drop write lock. Quota will retake it when needed and lock + * ordering requires calling dquot_suspend() without it. + */ + reiserfs_write_unlock(s); err = dquot_suspend(s, -1); if (err < 0) goto out_err; + reiserfs_write_lock(s); /* try to remount file system with read-only permissions */ if (sb_umount_state(rs) == REISERFS_VALID_FS @@ -1272,7 +1278,7 @@ static int reiserfs_remount(struct super err = journal_begin(&th, s, 10); if (err) - goto out_err; + goto out_unlock; /* Mounting a rw partition read-only. */ reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1); @@ -1287,7 +1293,7 @@ static int reiserfs_remount(struct super if (reiserfs_is_journal_aborted(journal)) { err = journal->j_errno; - goto out_err; + goto out_unlock; } handle_data_mode(s, mount_options); @@ -1296,7 +1302,7 @@ static int reiserfs_remount(struct super s->s_flags &= ~MS_RDONLY; /* now it is safe to call journal_begin */ err = journal_begin(&th, s, 10); if (err) - goto out_err; + goto out_unlock; /* Mount a partition which is read-only, read-write */ reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1); @@ -1313,11 +1319,17 @@ static int reiserfs_remount(struct super SB_JOURNAL(s)->j_must_wait = 1; err = journal_end(&th, s, 10); if (err) - goto out_err; + goto out_unlock; s->s_dirt = 0; if (!(*mount_flags & MS_RDONLY)) { + /* + * Drop write lock. Quota will retake it when needed and lock + * ordering requires calling dquot_resume() without it. + */ + reiserfs_write_unlock(s); dquot_resume(s, -1); + reiserfs_write_lock(s); finish_unfinished(s); reiserfs_xattr_init(s, *mount_flags); } @@ -1327,9 +1339,10 @@ out_ok: reiserfs_write_unlock(s); return 0; +out_unlock: + reiserfs_write_unlock(s); out_err: kfree(new_opts); - reiserfs_write_unlock(s); return err; }