| From | Herton Ronaldo Krzesinski <> | Subject | [PATCH 117/241] reiserfs: Fix lock ordering during remount | Date | Thu, 13 Dec 2012 11:58:02 -0200 |
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3.5.7.2 -stable review patch. If anyone has any objections, please let me know.
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From: Jan Kara <jack@suse.cz>
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 <jack@suse.cz> Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> --- fs/reiserfs/super.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-)
diff --git a/fs/reiserfs/super.c b/fs/reiserfs/super.c index 651ce76..2ad0789 100644 --- a/fs/reiserfs/super.c +++ b/fs/reiserfs/super.c @@ -1325,7 +1325,7 @@ static int reiserfs_remount(struct super_block *s, int *mount_flags, char *arg) kfree(qf_names[i]); #endif err = -EINVAL; - goto out_err; + goto out_unlock; } #ifdef CONFIG_QUOTA handle_quota_files(s, qf_names, &qfmt); @@ -1369,7 +1369,7 @@ static int reiserfs_remount(struct super_block *s, int *mount_flags, char *arg) if (blocks) { err = reiserfs_resize(s, blocks); if (err != 0) - goto out_err; + goto out_unlock; } if (*mount_flags & MS_RDONLY) { @@ -1379,9 +1379,15 @@ static int reiserfs_remount(struct super_block *s, int *mount_flags, char *arg) /* 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 @@ -1391,7 +1397,7 @@ static int reiserfs_remount(struct super_block *s, int *mount_flags, char *arg) 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); @@ -1406,7 +1412,7 @@ static int reiserfs_remount(struct super_block *s, int *mount_flags, char *arg) if (reiserfs_is_journal_aborted(journal)) { err = journal->j_errno; - goto out_err; + goto out_unlock; } handle_data_mode(s, mount_options); @@ -1415,7 +1421,7 @@ static int reiserfs_remount(struct super_block *s, int *mount_flags, char *arg) 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); @@ -1432,10 +1438,16 @@ static int reiserfs_remount(struct super_block *s, int *mount_flags, char *arg) SB_JOURNAL(s)->j_must_wait = 1; err = journal_end(&th, s, 10); if (err) - goto out_err; + goto out_unlock; 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); } @@ -1445,9 +1457,10 @@ 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; } -- 1.7.9.5
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