From c18c821fd40ad0ffc199a55be874e556bf999416 Mon Sep 17 00:00:00 2001
From: Boaz Harrosh <bharrosh@panasas.com>
Date: Tue, 29 Jun 2010 14:33:55 +0300
Subject: [PATCH] nfsd41: Fix a crash when a callback is retried
If a callback is retried at nfsd4_cb_recall_done() due to
some error, the returned rpc reply crashes here:
@@ -514,6 +514,7 @@ decode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_cb_sequence *res,
u32 dummy;
__be32 *p;
+ BUG_ON(!res);
if (res->cbs_minorversion == 0)
return 0;
[BUG_ON added for demonstration]
This is because the nfsd4_cb_done_sequence() has NULLed out
the task->tk_msg.rpc_resp pointer.
Also eventually the rpc would use the new slot without making
sure it is free by calling nfsd41_cb_setup_sequence().
This problem was introduced by a 4.1 protocol addition patch:
[0421b5c5] nfsd41: Backchannel: Implement cb_recall over NFSv4.1
Which was overlooking the possibility of an RPC callback retries.
For not-4.1 case redoing the _prepare is harmless.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
fs/nfsd/nfs4callback.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 1e6497ed3e12..988cbb3a19b6 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -697,7 +697,7 @@ static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
if (dp->dl_retries--) {
rpc_delay(task, 2*HZ);
task->tk_status = 0;
- rpc_restart_call(task);
+ rpc_restart_call_prepare(task);
return;
} else {
atomic_set(&clp->cl_cb_set, 0);
--
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