diff mbox series

[5.4,015/168] ceph: dont skip updating wanted caps when cap is stale

Message ID 20200428182233.626844888@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH April 28, 2020, 6:23 p.m. UTC 
From: Yan, Zheng <zyan@redhat.com>

[ Upstream commit 0aa971b6fd3f92afef6afe24ef78d9bb14471519 ]

1. try_get_cap_refs() fails to get caps and finds that mds_wanted
   does not include what it wants. It returns -ESTALE.
2. ceph_get_caps() calls ceph_renew_caps(). ceph_renew_caps() finds
   that inode has cap, so it calls ceph_check_caps().
3. ceph_check_caps() finds that issued caps (without checking if it's
   stale) already includes caps wanted by open file, so it skips
   updating wanted caps.

Above events can cause an infinite loop inside ceph_get_caps().

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-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 | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index f5a38910a82bf..703945cce0e5d 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1976,8 +1976,12 @@  retry_locked:
 		}
 
 		/* want more caps from mds? */
-		if (want & ~(cap->mds_wanted | cap->issued))
-			goto ack;
+		if (want & ~cap->mds_wanted) {
+			if (want & ~(cap->mds_wanted | cap->issued))
+				goto ack;
+			if (!__cap_is_valid(cap))
+				goto ack;
+		}
 
 		/* things we might delay */
 		if ((cap->issued & ~retain) == 0)