From 968b1dd03e74563d05b78f8b30227a521c982cce Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Tue, 10 Mar 2020 19:34:20 +0800 Subject: [PATCH] ceph: don't skip updating wanted caps when cap is stale [ 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" Reviewed-by: Jeff Layton Signed-off-by: Ilya Dryomov Signed-off-by: Sasha Levin --- fs/ceph/caps.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index c3a3ee74e2d8..1b5a50848b5b 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -1863,8 +1863,12 @@ 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 &&