Patch "ceph: unlock dangling spinlock in try_flush_caps()" has been added to the 4.4-stable tree

Patch "ceph: unlock dangling spinlock in try_flush_caps()" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    ceph: unlock dangling spinlock in try_flush_caps()

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ceph-unlock-dangling-spinlock-in-try_flush_caps.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 6c2838fbdedb9b72a81c931d49e56b229b6cdbca Mon Sep 17 00:00:00 2001
From: Jeff Layton <jlayton@redhat.com>
Date: Thu, 19 Oct 2017 08:52:58 -0400
Subject: ceph: unlock dangling spinlock in try_flush_caps()

From: Jeff Layton <jlayton@redhat.com>

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@redhat.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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);


Patches currently in stable-queue which might be from jlayton@redhat.com are

queue-4.4/ceph-unlock-dangling-spinlock-in-try_flush_caps.patch