X-Git-Url: https://git.decadent.org.uk/gitweb/?p=nfs-utils.git;a=blobdiff_plain;f=utils%2Fmount%2Fstropts.c;h=50a1a2a06626a72ba2c09fe656df3331e66a85b1;hp=024140082fcf56f65968453ca912158ab73f3668;hb=706bfd7c94d48659a1411fdef2a3a61d4719f1aa;hpb=26fd34002585e6a5aa09204b0b01d836fa83dcf3

diff --git a/utils/mount/stropts.c b/utils/mount/stropts.c
index 0241400..50a1a2a 100644
--- a/utils/mount/stropts.c
+++ b/utils/mount/stropts.c
@@ -302,11 +302,16 @@ static int nfs_set_version(struct nfsmount_info *mi)
 
 	if (strncmp(mi->type, "nfs4", 4) == 0)
 		mi->version = 4;
-	else {
-		char *option = po_get(mi->options, "proto");
-		if (option && strcmp(option, "rdma") == 0)
-			mi->version = 3;
-	}
+
+	/*
+	 * Before 2.6.32, the kernel NFS client didn't
+	 * support "-t nfs vers=4" mounts, so NFS version
+	 * 4 cannot be included when autonegotiating
+	 * while running on those kernels.
+	 */
+	if (mi->version == 0 &&
+	    linux_version_code() <= MAKE_VERSION(2, 6, 31))
+		mi->version = 3;
 
 	/*
 	 * If we still don't know, check for version-specific
@@ -490,14 +495,18 @@ nfs_rewrite_pmap_mount_options(struct mount_options *options)
 	union nfs_sockaddr mnt_address;
 	struct sockaddr *mnt_saddr = &mnt_address.sa;
 	socklen_t mnt_salen = sizeof(mnt_address);
+	unsigned long protocol;
 	struct pmap mnt_pmap;
-	char *option;
 
 	/*
-	 * Skip option negotiation for proto=rdma mounts.
+	 * Version and transport negotiation is not required
+	 * and does not work for RDMA mounts.
 	 */
-	option = po_get(options, "proto");
-	if (option && strcmp(option, "rdma") == 0)
+	if (!nfs_nfs_protocol(options, &protocol)) {
+		errno = EINVAL;
+		return 0;
+	}
+	if (protocol == NFSPROTO_RDMA)
 		goto out;
 
 	/*
@@ -746,6 +755,47 @@ static int nfs_try_mount_v4(struct nfsmount_info *mi)
 	return ret;
 }
 
+/*
+ * Handle NFS version and transport protocol
+ * autonegotiation.
+ *
+ * When no version or protocol is specified on the
+ * command line, mount.nfs negotiates with the server
+ * to determine appropriate settings for the new
+ * mount point.
+ *
+ * Returns TRUE if successful, otherwise FALSE.
+ * "errno" is set to reflect the individual error.
+ */
+static int nfs_autonegotiate(struct nfsmount_info *mi)
+{
+	int result;
+
+	result = nfs_try_mount_v4(mi);
+	if (result)
+		return result;
+		
+	switch (errno) {
+	case EPROTONOSUPPORT:
+		/* A clear indication that the server or our
+		 * client does not support NFS version 4. */
+		goto fall_back;
+	case ENOENT:
+		/* Legacy Linux servers don't export an NFS
+		 * version 4 pseudoroot. */
+		goto fall_back;
+	case EPERM:
+		/* Linux servers prior to 2.6.25 may return
+		 * EPERM when NFS version 4 is not supported. */
+		goto fall_back;
+	default:
+		return result;
+	}
+
+fall_back:
+	return nfs_try_mount_v3v2(mi);
+}
+
 /*
  * This is a single pass through the fg/bg loop.
  *
@@ -758,20 +808,8 @@ static int nfs_try_mount(struct nfsmount_info *mi)
 
 	switch (mi->version) {
 	case 0:
-		if (linux_version_code() > MAKE_VERSION(2, 6, 31)) {
-			errno = 0;
-			result = nfs_try_mount_v4(mi);
-			if (errno != EPROTONOSUPPORT) {
-				/* 
-				 * To deal with legacy Linux servers that don't
-				 * automatically export a pseudo root, retry
-				 * ENOENT errors using version 3. And for
-				 * Linux servers prior to 2.6.25, retry EPERM
-				 */
-				if (errno != ENOENT && errno != EPERM)
-					break;
-			}
-		}
+		result = nfs_autonegotiate(mi);
+		break;
 	case 2:
 	case 3:
 		result = nfs_try_mount_v3v2(mi);
@@ -928,6 +966,26 @@ static int nfsmount_bg(struct nfsmount_info *mi)
 		return nfsmount_child(mi);
 }
 
+/*
+ * Usually all that is needed for an NFS remount is to change
+ * generic mount options like "sync" or "ro".  These generic
+ * options are controlled by mi->flags, not by text-based
+ * options, and no contact with the server is needed.
+ *
+ * Take care with the /etc/mtab entry for this mount; just
+ * calling update_mtab() will change an "-t nfs -o vers=4"
+ * mount to an "-t nfs -o remount" mount, and that will
+ * confuse umount.nfs.
+ *
+ * Returns a valid mount command exit code.
+ */
+static int nfs_remount(struct nfsmount_info *mi)
+{
+	if (nfs_sys_mount(mi, mi->options))
+		return EX_SUCCESS;
+	return EX_FAIL;
+}
+
 /*
  * Process mount options and try a mount system call.
  *
@@ -944,6 +1002,12 @@ static int nfsmount_start(struct nfsmount_info *mi)
 	if (!nfs_validate_options(mi))
 		return EX_FAIL;
 
+	/*
+	 * Avoid retry and negotiation logic when remounting
+	 */
+	if (mi->flags & MS_REMOUNT)
+		return nfs_remount(mi);
+
 	if (po_rightmost(mi->options, nfs_background_opttbl) == 0)
 		return nfsmount_bg(mi);
 	else
@@ -960,6 +1024,8 @@ static int nfsmount_start(struct nfsmount_info *mi)
  *		(input and output argument)
  * @fake: flag indicating whether to carry out the whole operation
  * @child: one if this is a mount daemon (bg)
+ *
+ * Returns a valid mount command exit code.
  */
 int nfsmount_string(const char *spec, const char *node, const char *type,
 		    int flags, char **extra_opts, int fake, int child)