On 2020/4/28 21:41, Yan, Zheng wrote:
On Tue, Apr 28, 2020 at 8:50 PM Wu Bo <wubo40@xxxxxxxxxx> wrote:
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.
at retry label, i_ceph_lock get locked. I don't see how i_ceph_lock
can get double unlock
sorry, maybe I didn't describe it clearly enough, not i_ceph_lock, but
session->s_mutex.
Thanks.
Wu Bo
Signed-off-by: Wu Bo <wubo40@xxxxxxxxxx>
---
fs/ceph/caps.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 185db76..b5a62a8 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -3731,22 +3731,24 @@ 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);
+ 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
.
