Patch "NFSv4.1: nfs41_clear_delegation_stateid shouldn't trust NFS_DELEGATED_STATE" has been added to the 3.14-stable tree

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This is a note to let you know that I've just added the patch titled

    NFSv4.1: nfs41_clear_delegation_stateid shouldn't trust NFS_DELEGATED_STATE

to the 3.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     nfsv4.1-nfs41_clear_delegation_stateid-shouldn-t-trust-nfs_delegated_state.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 0c116cadd94b16b30b1dd90d38b2784d9b39b01a Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Date: Wed, 12 Nov 2014 14:44:49 -0500
Subject: NFSv4.1: nfs41_clear_delegation_stateid shouldn't trust NFS_DELEGATED_STATE

From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>

commit 0c116cadd94b16b30b1dd90d38b2784d9b39b01a upstream.

This patch removes the assumption made previously, that we only need to
check the delegation stateid when it matches the stateid on a cached
open.

If we believe that we hold a delegation for this file, then we must assume
that its stateid may have been revoked or expired too. If we don't test it
then our state recovery process may end up caching open/lock state in a
situation where it should not.
We therefore rename the function nfs41_clear_delegation_stateid as
nfs41_check_delegation_stateid, and change it to always run through the
delegation stateid test and recovery process as outlined in RFC5661.

http://lkml.kernel.org/r/CAN-5tyHwG=Cn2Q9KsHWadewjpTTy_K26ee+UnSvHvG4192p-Xw@xxxxxxxxxxxxxx
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/nfs/nfs4proc.c |   42 +++++++++++++++++-------------------------
 1 file changed, 17 insertions(+), 25 deletions(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2057,45 +2057,37 @@ static int nfs40_open_expired(struct nfs
 }
 
 #if defined(CONFIG_NFS_V4_1)
-static void nfs41_clear_delegation_stateid(struct nfs4_state *state)
+static void nfs41_check_delegation_stateid(struct nfs4_state *state)
 {
 	struct nfs_server *server = NFS_SERVER(state->inode);
-	nfs4_stateid *stateid = &state->stateid;
+	nfs4_stateid stateid;
 	struct nfs_delegation *delegation;
-	struct rpc_cred *cred = NULL;
-	int status = -NFS4ERR_BAD_STATEID;
-
-	/* If a state reset has been done, test_stateid is unneeded */
-	if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
-		return;
+	struct rpc_cred *cred;
+	int status;
 
 	/* Get the delegation credential for use by test/free_stateid */
 	rcu_read_lock();
 	delegation = rcu_dereference(NFS_I(state->inode)->delegation);
-	if (delegation != NULL &&
-	    nfs4_stateid_match(&delegation->stateid, stateid)) {
-		cred = get_rpccred(delegation->cred);
-		rcu_read_unlock();
-		status = nfs41_test_stateid(server, stateid, cred);
-		trace_nfs4_test_delegation_stateid(state, NULL, status);
-	} else
+	if (delegation == NULL) {
 		rcu_read_unlock();
+		return;
+	}
+
+	nfs4_stateid_copy(&stateid, &delegation->stateid);
+	cred = get_rpccred(delegation->cred);
+	rcu_read_unlock();
+	status = nfs41_test_stateid(server, &stateid, cred);
+	trace_nfs4_test_delegation_stateid(state, NULL, status);
 
 	if (status != NFS_OK) {
 		/* Free the stateid unless the server explicitly
 		 * informs us the stateid is unrecognized. */
 		if (status != -NFS4ERR_BAD_STATEID)
-			nfs41_free_stateid(server, stateid, cred);
-		nfs_remove_bad_delegation(state->inode);
-
-		write_seqlock(&state->seqlock);
-		nfs4_stateid_copy(&state->stateid, &state->open_stateid);
-		write_sequnlock(&state->seqlock);
-		clear_bit(NFS_DELEGATED_STATE, &state->flags);
+			nfs41_free_stateid(server, &stateid, cred);
+		nfs_finish_clear_delegation_stateid(state);
 	}
 
-	if (cred != NULL)
-		put_rpccred(cred);
+	put_rpccred(cred);
 }
 
 /**
@@ -2139,7 +2131,7 @@ static int nfs41_open_expired(struct nfs
 {
 	int status;
 
-	nfs41_clear_delegation_stateid(state);
+	nfs41_check_delegation_stateid(state);
 	status = nfs41_check_open_stateid(state);
 	if (status != NFS_OK)
 		status = nfs4_open_expired(sp, state);


Patches currently in stable-queue which might be from trond.myklebust@xxxxxxxxxxxxxxx are

queue-3.14/nfsv4-ensure-that-we-remove-nfsv4.0-delegations-when-state-has-expired.patch
queue-3.14/nfsv4.1-nfs41_clear_delegation_stateid-shouldn-t-trust-nfs_delegated_state.patch
queue-3.14/nfsv4-fix-races-between-nfs_remove_bad_delegation-and-delegation-return.patch
queue-3.14/nfs-fix-use-of-uninitialized-variable-in-nfs_getattr.patch
queue-3.14/nfs-fix-pnfs-direct-write-memory-leak.patch
queue-3.14/nfs-don-t-try-to-reclaim-delegation-open-state-if-recovery-failed.patch
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