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Message-ID: <1588079622-423774-1-git-send-email-wubo40@huawei.com>
Date: Tue, 28 Apr 2020 21:13:42 +0800
From: Wu Bo <wubo40@...wei.com>
To: <jlayton@...nel.org>, <sage@...hat.com>, <idryomov@...il.com>
CC: <ceph-devel@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<liuzhiqiang26@...wei.com>, <linfeilong@...wei.com>,
<wubo40@...wei.com>
Subject: [PATCH V2] fs/ceph:fix double unlock in handle_cap_export()
if the ceph_mdsc_open_export_target_session() return fails,
should add a lock to avoid twice unlocking.
Because the lock will be released at the retry or out_unlock tag.
--
v1 -> v2:
add spin_lock(&ci->i_ceph_lock) before goto out_unlock tag.
Signed-off-by: Wu Bo <wubo40@...wei.com>
---
fs/ceph/caps.c | 27 +++++++++++++++------------
1 file changed, 15 insertions(+), 12 deletions(-)
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 185db76..414c0e2 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -3731,22 +3731,25 @@ static void handle_cap_export(struct inode *inode, struct ceph_mds_caps *ex,
/* open target session */
tsession = ceph_mdsc_open_export_target_session(mdsc, target);
- if (!IS_ERR(tsession)) {
- if (mds > target) {
- mutex_lock(&session->s_mutex);
- mutex_lock_nested(&tsession->s_mutex,
- SINGLE_DEPTH_NESTING);
- } else {
- mutex_lock(&tsession->s_mutex);
- mutex_lock_nested(&session->s_mutex,
- SINGLE_DEPTH_NESTING);
- }
- new_cap = ceph_get_cap(mdsc, NULL);
- } else {
+ if (IS_ERR(tsession)) {
WARN_ON(1);
tsession = NULL;
target = -1;
+ mutex_lock(&session->s_mutex);
+ spin_lock(&ci->i_ceph_lock);
+ goto out_unlock;
+ }
+
+ if (mds > target) {
+ mutex_lock(&session->s_mutex);
+ mutex_lock_nested(&tsession->s_mutex,
+ SINGLE_DEPTH_NESTING);
+ } else {
+ mutex_lock(&tsession->s_mutex);
+ mutex_lock_nested(&session->s_mutex,
+ SINGLE_DEPTH_NESTING);
}
+ new_cap = ceph_get_cap(mdsc, NULL);
goto retry;
out_unlock:
--
1.8.3.1
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