MFC: r308871

Modify umount so that it does not do an Unmount RPC for NFSv4 mounts
and uses TCP for the Unmount RPC if the mount is over TCP.
Without this patch, umount does an Unmount RPC over UDP for all NFS mounts.

1 files changed, 22 insertions, 2 deletions

diff --git a/sbin/umount/umount.c b/sbin/umount/umount.c
index 521bbc8..ccd15f5 100644
--- a/sbin/umount/umount.c
+++ b/sbin/umount/umount.c
@@ -49,6 +49,7 @@ static const char rcsid[] =
 #include <netdb.h>
 #include <rpc/rpc.h>
 #include <rpcsvc/mount.h>
+#include <nfs/nfssvc.h>
 
 #include <ctype.h>
 #include <err.h>
@@ -317,6 +318,9 @@ umountfs(struct statfs *sfs)
 	CLIENT *clp;
 	char *nfsdirname, *orignfsdirname;
 	char *hostp, *delimp;
+	char buf[1024];
+	struct nfscl_dumpmntopts dumpmntopts;
+	const char *proto_ptr = NULL;
 
 	ai = NULL;
 	do_rpc = 0;
@@ -355,8 +359,24 @@ umountfs(struct statfs *sfs)
 		 * mount from mntfromname that is still mounted.
 		 */
 		if (getmntentry(sfs->f_mntfromname, NULL, NULL,
-		    CHECKUNIQUE) != NULL)
+		    CHECKUNIQUE) != NULL) {
 			do_rpc = 1;
+			proto_ptr = "udp";
+			/*
+			 * Try and find out whether this NFS mount is NFSv4 and
+			 * what protocol is being used. If this fails, the
+			 * default is NFSv2,3 and use UDP for the Unmount RPC.
+			 */
+			dumpmntopts.ndmnt_fname = sfs->f_mntonname;
+			dumpmntopts.ndmnt_buf = buf;
+			dumpmntopts.ndmnt_blen = sizeof(buf);
+			if (nfssvc(NFSSVC_DUMPMNTOPTS, &dumpmntopts) >= 0) {
+				if (strstr(buf, "nfsv4,") != NULL)
+					do_rpc = 0;
+				else if (strstr(buf, ",tcp,") != NULL)
+					proto_ptr = "tcp";
+			}
+		}
 	}
 
 	if (!namematch(ai)) {
@@ -394,7 +414,7 @@ umountfs(struct statfs *sfs)
 	 * has been unmounted.
 	 */
 	if (ai != NULL && !(fflag & MNT_FORCE) && do_rpc) {
-		clp = clnt_create(hostp, MOUNTPROG, MOUNTVERS3, "udp");
+		clp = clnt_create(hostp, MOUNTPROG, MOUNTVERS3, proto_ptr);
 		if (clp  == NULL) {
 			warnx("%s: %s", hostp,
 			    clnt_spcreateerror("MOUNTPROG"));