[PATCH v2] common/rc: fix mount options quoting in _mount

[lan@suse.com]

From: An Long <lan@suse.com>

In commit 078f320 ("treewide: convert all $MOUNT_PROG to _mount"),
direct calls to $MOUNT_PROG were converted to call the helper function
_mount.
However, the _mount helper was implemented using `$*` instead of `"$@"`.
This unquoted argument expansion triggers word splitting on any arguments
containing spaces (such as the overlay mount options containing spaces in
tests `overlay/083` and `overlay/086`), causing the mount to fail with
"mount: bad usage".
Fix this regression by using `"$@"` in the _mount helper, which correctly
preserves argument boundaries exactly as they were provided by the caller.

Signed-off-by: An Long <lan@suse.com>
---
V1 -> V2: Revert the error log to "$*"

v1: https://lore.kernel.org/fstests/20260629155812.GW6070@frogsfrogsfrogs/T/#t

 common/rc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/common/rc b/common/rc
index 79189e7e..b9a07324 100644
--- a/common/rc
+++ b/common/rc
@@ -296,7 +296,7 @@ _has_dmesg_since_option()
 
 _mount()
 {
-	$MOUNT_PROG $*
+	$MOUNT_PROG "$@"
 	ret=$?
 	if [ "$ret" -ne 0 ]; then
 		echo "\"$MOUNT_PROG $*\" failed at $(date)" >> "$seqres.mountfail?"
-- 
2.51.0