linux-kernel - [PATCH AUTOSEL 5.2 081/123] NFSv4: When recovering state fails with EAGAIN, retry the same recovery

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Date:   Tue, 13 Aug 2019 22:10:05 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Trond Myklebust <trond.myklebust@...merspace.com>,
        Sasha Levin <sashal@...nel.org>, linux-nfs@...r.kernel.org
Subject: [PATCH AUTOSEL 5.2 081/123] NFSv4: When recovering state fails with EAGAIN, retry the same recovery

From: Trond Myklebust <trond.myklebust@...merspace.com>

[ Upstream commit c34fae003c79570b6c930b425fea3f0b7b1e7056 ]

If the server returns with EAGAIN when we're trying to recover from
a server reboot, we currently delay for 1 second, but then mark the
stateid as needing recovery after the grace period has expired.

Instead, we should just retry the same recovery process immediately
after the 1 second delay. Break out of the loop after 10 retries.

Fixes: 35a61606a612 ("NFS: Reduce indentation of the switch statement...")
Signed-off-by: Trond Myklebust <trond.myklebust@...merspace.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/nfs/nfs4state.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index e2e3c4f04d3e0..556ec916846f0 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1606,6 +1606,7 @@ static int __nfs4_reclaim_open_state(struct nfs4_state_owner *sp, struct nfs4_st
 static int nfs4_reclaim_open_state(struct nfs4_state_owner *sp, const struct nfs4_state_recovery_ops *ops)
 {
 	struct nfs4_state *state;
+	unsigned int loop = 0;
 	int status = 0;
 
 	/* Note: we rely on the sp->so_states list being ordered 
@@ -1632,8 +1633,10 @@ static int nfs4_reclaim_open_state(struct nfs4_state_owner *sp, const struct nfs
 
 		switch (status) {
 		default:
-			if (status >= 0)
+			if (status >= 0) {
+				loop = 0;
 				break;
+			}
 			printk(KERN_ERR "NFS: %s: unhandled error %d\n", __func__, status);
 			/* Fall through */
 		case -ENOENT:
@@ -1647,6 +1650,10 @@ static int nfs4_reclaim_open_state(struct nfs4_state_owner *sp, const struct nfs
 			break;
 		case -EAGAIN:
 			ssleep(1);
+			if (loop++ < 10) {
+				set_bit(ops->state_flag_bit, &state->flags);
+				break;
+			}
 			/* Fall through */
 		case -NFS4ERR_ADMIN_REVOKED:
 		case -NFS4ERR_STALE_STATEID:
-- 
2.20.1