[PATCH] mount.c: bail out early when no media exists

[sgw at linux.intel.com]

From: "Maxin B. John" <maxin.john at intel.com>

The current behaviour of busybox is to try all fstype when automounting
even when no media exists.  The util-linux mount command bails when
no media exists, so change the behaviour of busybox to do the same.

without this fix:
$ time ./busybox mount /dev/cdrom /mnt
mount: mounting /dev/cdrom on /mnt failed: No medium found

real	0m0.573s
user	0m0.000s
sys	0m0.007s

with this fix:
$ time ./busybox mount /dev/cdrom /mnt
mount: mounting /dev/cdrom on /mnt failed: No medium found

real	0m0.042s
user	0m0.000s
sys	0m0.002s

Signed-off-by: Saul Wold <sgw at linux.intel.com>
Signed-off-by: Maxin B. John <maxin.john at intel.com>
---
 util-linux/mount.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/util-linux/mount.c b/util-linux/mount.c
index cb40c80..2953758 100644
--- a/util-linux/mount.c
+++ b/util-linux/mount.c
@@ -710,7 +710,13 @@ static int mount_it_now(struct mntent *mp, unsigned long vfsflags, char *filtero
 				break;
 			errno = errno_save;
 		}
-
+		/*
+		 * Break if there is no media, no point retrying for all
+		 * fs types since there is no media available
+		 */
+		if (rc == -1 && errno == ENOMEDIUM) {
+			bb_perror_msg_and_die("mounting %s on %s failed", mp->mnt_fsname, mp->mnt_dir);
+		}
 		if (!rc || (vfsflags & MS_RDONLY) || (errno != EACCES && errno != EROFS))
 			break;
 		if (!(vfsflags & MS_SILENT))
-- 
2.4.0