Patch "NFSD: fix nfsd_reset_versions for NFSv4." has been added to the 4.9-stable tree

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

NFSD: fix nfsd_reset_versions for NFSv4.

to the 4.9-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:
nfsd-fix-nfsd_reset_versions-for-nfsv4.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: NeilBrown <[email protected]>
Date: Fri, 10 Mar 2017 11:36:39 +1100
Subject: NFSD: fix nfsd_reset_versions for NFSv4.

From: NeilBrown <[email protected]>

[ Upstream commit 800a938f0bf9130c8256116649c0cc5806bfb2fd ]

If you write "-2 -3 -4" to the "versions" file, it will notice that no versions are enabled, and nfsd_reset_versions() is called.
This enables all major versions, not no minor versions. So we lose the invariant that NFSv4 is only advertised when at least one minor is enabled.

Fix the code to explicitly enable minor versions for v4, change it to use nfsd_vers() to test and set, and simplify the code.

---
 fs/nfsd/nfssvc.c |   25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

@@ -400,23 +400,20 @@ static void nfsd_last_thread(struct svc_
 
 void nfsd_reset_versions(void)
 {
-	int found_one = 0;
 	int i;
 
-	for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++) {
-		if (nfsd_program.pg_vers[i])
-			found_one = 1;
-	}
+	for (i = 0; i < NFSD_NRVERS; i++)
+		if (nfsd_vers(i, NFSD_TEST))
+			return;
 
-	if (!found_one) {
-		for (i = NFSD_MINVERS; i < NFSD_NRVERS; i++)
-			nfsd_program.pg_vers[i] = nfsd_version[i];
-#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
-		for (i = NFSD_ACL_MINVERS; i < NFSD_ACL_NRVERS; i++)
-			nfsd_acl_program.pg_vers[i] =
-				nfsd_acl_version[i];
-#endif
-	}
+	for (i = 0; i < NFSD_NRVERS; i++)
+		if (i != 4)
+			nfsd_vers(i, NFSD_SET);
+		else {
+			int minor = 0;
+			while (nfsd_minorversion(minor, NFSD_SET) >= 0)
+				minor++;
+		}
 }
 
 /*

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/md-cluster-free-md_cluster_info-if-node-leave-cluster.patch queue-4.9/autofs-fix-careless-error-in-recent-commit.patch queue-4.9/raid5-set-r5_expanded-on-parity-devices-as-well-as-data.patch queue-4.9/nfsd-fix-nfsd_reset_versions-for-nfsv4.patch queue-4.9/nfsd-fix-nfsd_minorversion-..-nfsd_avail.patch