linux-kernel - [PATCH 3.2 018/110] fixing infinite OPEN loop in 4.0 stateid recovery

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Message-ID: <lsq.1439201550.564295464@decadent.org.uk>
Date:	Mon, 10 Aug 2015 12:12:30 +0200
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:	akpm@...ux-foundation.org,
	"Trond Myklebust" <trond.myklebust@...marydata.com>,
	"Olga Kornievskaia" <kolga@...app.com>
Subject: [PATCH 3.2 018/110] fixing infinite OPEN loop in 4.0 stateid recovery

3.2.71-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Olga Kornievskaia <kolga@...app.com>

commit e8d975e73e5fa05f983fbf2723120edcf68e0b38 upstream.

Problem: When an operation like WRITE receives a BAD_STATEID, even though
recovery code clears the RECLAIM_NOGRACE recovery flag before recovering
the open state, because of clearing delegation state for the associated
inode, nfs_inode_find_state_and_recover() gets called and it makes the
same state with RECLAIM_NOGRACE flag again. As a results, when we restart
looking over the open states, we end up in the infinite loop instead of
breaking out in the next test of state flags.

Solution: unset the RECLAIM_NOGRACE set because of
calling of nfs_inode_find_state_and_recover() after returning from calling
recover_open() function.

Signed-off-by: Olga Kornievskaia <kolga@...app.com>
Signed-off-by: Trond Myklebust <trond.myklebust@...marydata.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 fs/nfs/nfs4state.c | 2 ++
 1 file changed, 2 insertions(+)

--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1192,6 +1192,8 @@ restart:
 				}
 				spin_unlock(&state->state_lock);
 				nfs4_put_open_state(state);
+				clear_bit(NFS4CLNT_RECLAIM_NOGRACE,
+					&state->flags);
 				goto restart;
 			}
 		}

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