When ocfs2 quota recovery races with umount, it can happen that umount
waits for recovery to finish while quota recovery waits to grab s_umount
semaphore held by umount. This results in a deadlock. Fix the problem by
not grabbing s_umount semaphore during quota recovery. We are protected
from disabling of quotas by the fact that quotas gets disabled only on
umount and that happens after recovery is disabled.
Reported-by: Shichangkuo <shi.chang...@h3c.com>
Signed-off-by: Jan Kara <j...@suse.cz>
---
fs/ocfs2/quota_local.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/fs/ocfs2/quota_local.c b/fs/ocfs2/quota_local.c
index 16c42ed0dca8..d60d744bbcb2 100644
--- a/fs/ocfs2/quota_local.c
+++ b/fs/ocfs2/quota_local.c
@@ -454,8 +454,10 @@ struct ocfs2_quota_recovery *ocfs2_begin_quota_recovery(
/* Sync changes in local quota file into global quota file and
* reinitialize local quota file.
- * The function expects local quota file to be already locked and
- * s_umount locked in shared mode. */
+ * The function expects local quota file to be already locked. Quota is
+ * disabled only during umount after disabling recovery so we are protected
+ * against that.
+ */
static int ocfs2_recover_local_quota_file(struct inode *lqinode,
int type,
struct ocfs2_quota_recovery *rec)
@@ -586,7 +588,6 @@ int ocfs2_finish_quota_recovery(struct ocfs2_super *osb,
{
unsigned int ino[OCFS2_MAXQUOTAS] = { LOCAL_USER_QUOTA_SYSTEM_INODE,
LOCAL_GROUP_QUOTA_SYSTEM_INODE };
- struct super_block *sb = osb->sb;
struct ocfs2_local_disk_dqinfo *ldinfo;
struct buffer_head *bh;
handle_t *handle;
@@ -598,7 +599,6 @@ int ocfs2_finish_quota_recovery(struct ocfs2_super *osb,
printk(KERN_NOTICE "ocfs2: Finishing quota recovery on device (%s) for "
"slot %u\n", osb->dev_str, slot_num);
- down_read(&sb->s_umount);
for (type = 0; type < OCFS2_MAXQUOTAS; type++) {
if (list_empty(&(rec->r_list[type])))
continue;
@@ -675,7 +675,6 @@ int ocfs2_finish_quota_recovery(struct ocfs2_super *osb,
break;
}
out:
- up_read(&sb->s_umount);
kfree(rec);
return status;
}
@@ -837,9 +836,10 @@ static int ocfs2_local_free_info(struct super_block *sb,
int type)
ocfs2_release_local_quota_bitmaps(&oinfo->dqi_chunk);
/*
- * s_umount held in exclusive mode protects us against racing with
- * recovery thread...
+ * Recovery should be already disabled at this point so that we cannot
+ * race with quota recovery.
*/
+ WARN_ON(!OCFS2_SB(sb)->disable_recovery);
if (oinfo->dqi_rec) {
ocfs2_free_quota_recovery(oinfo->dqi_rec);
mark_clean = 0;
--
2.13.6
_______________________________________________
Ocfs2-devel mailing list
Ocfs2-devel@oss.oracle.com
https://oss.oracle.com/mailman/listinfo/ocfs2-devel
