[PATCH 4.4 04/20] ceph: unlock dangling spinlock in try_flush_caps()

From: Greg Kroah-Hartman
Date: Tue Oct 31 2017 - 06:17:38 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jeff Layton <jlayton@xxxxxxxxxx>

commit 6c2838fbdedb9b72a81c931d49e56b229b6cdbca upstream.

sparse warns:

fs/ceph/caps.c:2042:9: warning: context imbalance in 'try_flush_caps' - wrong count at exit

We need to exit this function with the lock unlocked, but a couple of
cases leave it locked.

Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
Reviewed-by: "Yan, Zheng" <zyan@xxxxxxxxxx>
Reviewed-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/ceph/caps.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1850,6 +1850,7 @@ static int try_flush_caps(struct inode *
retry:
spin_lock(&ci->i_ceph_lock);
if (ci->i_ceph_flags & CEPH_I_NOFLUSH) {
+ spin_unlock(&ci->i_ceph_lock);
dout("try_flush_caps skipping %p I_NOFLUSH set\n", inode);
goto out;
}
@@ -1867,8 +1868,10 @@ retry:
mutex_lock(&session->s_mutex);
goto retry;
}
- if (cap->session->s_state < CEPH_MDS_SESSION_OPEN)
+ if (cap->session->s_state < CEPH_MDS_SESSION_OPEN) {
+ spin_unlock(&ci->i_ceph_lock);
goto out;
+ }

flushing = __mark_caps_flushing(inode, session, &flush_tid,
&oldest_flush_tid);