From b71ac8086a7b4d8281e1157762b9d56e41f12865 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 f5a3891..703945c 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) -- 2.7.4