fixes for protocol fallback on mount

Two unrelated patches which both relate to protocol fallback when mounting an NFS filesystem.

---

Andreas Schwab (1):
Fix uninitialised variable usage in nfs_options2pmap

NeilBrown (1):
Fix protocol minor version fall-back

 utils/mount/network.c |    5 ++++-
 utils/mount/stropts.c |    3 +++
 2 files changed, 7 insertions(+), 1 deletion(-)

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Signature

From: Andreas Schwab <[email protected]>

Commit 5bea22e33b7a introduced a regression. Prior to that commit nfs_nfs_version would set *version to 0 if NFS version wasn't specified. Since that commit, version.v_mode is set to V_DEFAULT if the NFS version isn't specified, but nfs_options2pmap uses version.major without checking v_mode. This can lead to incorrect behaviour.
In particular fall-ack to v3 if server doesn't support v4 can fail.

So test v_mode before using version.major.

URL: https://bugzilla.opensuse.org/show_bug.cgi?id=956743

---
 utils/mount/network.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

index ebc39d361e2c..8a9bf1476d51 100644
@@ -1631,7 +1631,10 @@ int nfs_options2pmap(struct mount_options *options,
 		return 0;
 	if (!nfs_nfs_version(options, &version))
 		return 0;
-	nfs_pmap->pm_vers = version.major;
+	if (version.v_mode == V_DEFAULT)
+		nfs_pmap->pm_vers = 0;
+	else
+		nfs_pmap->pm_vers = version.major;
 	if (!nfs_nfs_protocol(options, &nfs_pmap->pm_prot))
 		return 0;
 	if (!nfs_nfs_port(options, &nfs_pmap->pm_port))

mount.nfs currently expects mount(2) to fail with EPROTONOSUPPORT if the kernel doesn't understand the requested NFS version.

Unfortunately if the requested minor is not known to the kernel it returns -EINVAL.
In kernels since 3.11 this can happen in nfs4_alloc_client(), if compiled without NFS_V4_2.

More generally it can happen in in nfs_validate_text_mount_data() when nfs_parse_mount_options() returns 0 because nfs_parse_version_string() didn't recognise the version.

EPROTONOSUPPORT is only returned if NFSv4 support is completely compiled out.

So nfs_autonegotiate needs to check for EINVAL as well as EPROTONOSUPPORT.

URL: https://bugzilla.opensuse.org/show_bug.cgi?id=959211

---
 utils/mount/stropts.c |    3 +++
 1 file changed, 3 insertions(+)

index c8f5a6d223e7..86829a902bfd 100644
@@ -841,6 +841,9 @@ check_result:
 	case EPROTONOSUPPORT:
 		/* A clear indication that the server or our
 		 * client does not support NFS version 4 and minor */
+	case EINVAL:
+		/* A less clear indication that our client
+		 * does not support NFSv4 minor version. */
 		if (mi->version.v_mode == V_GENERAL &&
 			mi->version.minor == 0)
 				return result;

Both patches committed! Thank you!!

steved.