cifs: escape spaces in share names

Commit 653a5efb849a ("cifs: update super_operations to show_devname")
introduced the display of devname for cifs mounts. However, when mounting
a share which has a whitespace in the name, that exact share name is also
displayed in mountinfo. Make sure that all whitespace is escaped.

Signed-off-by: Maciek Borzecki <maciek.borzecki@gmail.com>
CC: <stable@vger.kernel.org> # 5.11+
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 099ad9f..5ddd20b 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -476,7 +476,8 @@
 		seq_puts(m, "none");
 	else {
 		convert_delimiter(devname, '/');
-		seq_puts(m, devname);
+		/* escape all spaces in share names */
+		seq_escape(m, devname, " \t");
 		kfree(devname);
 	}
 	return 0;