[PATCH 4.11 067/114] Fix match_prepath()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.11-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sachin Prabhu <sprabhu@redhat.com>

commit cd8c42968ee651b69e00f8661caff32b0086e82d upstream.

Incorrect return value for shares not using the prefix path means that
we will never match superblocks for these shares.

Fixes: commit c1d8b24d1819 ("Compare prepaths when comparing superblocks")
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/cifs/connect.c |   14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2912,16 +2912,14 @@ match_prepath(struct super_block *sb, st
 {
 	struct cifs_sb_info *old = CIFS_SB(sb);
 	struct cifs_sb_info *new = mnt_data->cifs_sb;
+	bool old_set = old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH;
+	bool new_set = new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH;
 
-	if (old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) {
-		if (!(new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH))
-			return 0;
-		/* The prepath should be null terminated strings */
-		if (strcmp(new->prepath, old->prepath))
-			return 0;
-
+	if (old_set && new_set && !strcmp(new->prepath, old->prepath))
+		return 1;
+	else if (!old_set && !new_set)
 		return 1;
-	}
+
 	return 0;
 }