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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, "Yan, Zheng" <zyan@redhat.com>,
        Jeff Layton <jlayton@kernel.org>,
        Ilya Dryomov <idryomov@gmail.com>,
        Sasha Levin <sashal@kernel.org>,
        =?UTF-8?q?Andrej=20Filip=C4=8Di=C4=8D?= <andrej.filipcic@ijs.si>
Subject: [PATCH 5.4 095/142] ceph: flush release queue when handling caps for unknown inode
Date:   Mon,  1 Jun 2020 19:54:13 +0200
Message-Id: <20200601174047.815799572@linuxfoundation.org>
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From: Jeff Layton <jlayton@kernel.org>

[ Upstream commit fb33c114d3ed5bdac230716f5b0a93b56b92a90d ]

It's possible for the VFS to completely forget about an inode, but for
it to still be sitting on the cap release queue. If the MDS sends the
client a cap message for such an inode, it just ignores it today, which
can lead to a stall of up to 5s until the cap release queue is flushed.

If we get a cap message for an inode that can't be located, then go
ahead and flush the cap release queue.

Cc: stable@vger.kernel.org
URL: https://tracker.ceph.com/issues/45532
Fixes: 1e9c2eb6811e ("ceph: delete stale dentry when last reference is dropped")
Reported-and-Tested-by: Andrej Filipčič <andrej.filipcic@ijs.si>
Suggested-by: Yan, Zheng <zyan@redhat.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/ceph/caps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 2d602c2b0ff6..b2695919435e 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -3938,7 +3938,7 @@ void ceph_handle_caps(struct ceph_mds_session *session,
 			__ceph_queue_cap_release(session, cap);
 			spin_unlock(&session->s_cap_lock);
 		}
-		goto done;
+		goto flush_cap_releases;
 	}
 
 	/* these will work even if we don't have a cap yet */
-- 
2.25.1