From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: [PATCH AUTOSEL 5.4 13/78] ceph: don't skip updating wanted caps when cap is stale Date: Sat, 18 Apr 2020 10:39:42 -0400 Message-ID: <20200418144047.9013-13-sashal@kernel.org> References: <20200418144047.9013-1-sashal@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200418144047.9013-1-sashal@kernel.org> Sender: stable-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Yan, Zheng" , Jeff Layton , Ilya Dryomov , Sasha Levin , ceph-devel@vger.kernel.org List-Id: ceph-devel.vger.kernel.org From: "Yan, Zheng" [ 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 f5a38910a82bf..703945cce0e5d 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -1976,8 +1976,12 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags, } /* 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) -- 2.20.1