libspl/mnttab: remove struct extmnttab

The two additional fields are never used by calling code, and we can
replace their sole internal use with an extra stack param.

Sponsored-by: TrueNAS
Reviewed-by: Ameer Hamza <ahamza@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <rob.norris@truenas.com>
Closes #18296

cmd/zfs/zfs_main.c

@@ -7694,15 +7694,11 @@ unshare_unmount_path(int op, char *path, int flags, boolean_t is_manual)
 	zfs_handle_t *zhp;
 	int ret = 0;
 	struct stat64 statbuf;
-	struct extmnttab entry;
+	struct mnttab entry;
 	const char *cmdname = (op == OP_SHARE) ? "unshare" : "unmount";
 	ino_t path_inode;
 	char *zfs_mntpnt, *entry_mntpnt;
 
-	/*
-	 * Search for the given (major,minor) pair in the mount table.
-	 */
-
 	if (getextmntent(path, &entry, &statbuf) != 0) {
 		if (op == OP_SHARE) {
 			(void) fprintf(stderr, gettext("cannot %s '%s': not "

cmd/zinject/translate.c

@@ -85,7 +85,7 @@ static int
 parse_pathname(const char *inpath, char *dataset, char *relpath,
     struct stat64 *statbuf)
 {
-	struct extmnttab mp;
+	struct mnttab mp;
 	const char *rel;
 	char fullpath[MAXPATHLEN];