[AFS]: Handle multiple mounts of an AFS superblock correctly.

Handle multiple mounts of an AFS superblock correctly, checking to see
whether the superblock is already initialised after calling sget()
rather than just unconditionally stamping all over it.

Also delete the "silent" parameter to afs_fill_super() as it's not
used and can, in any case, be obtained from sb->s_flags.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/fs/afs/super.c b/fs/afs/super.c
index efc4fe6..77e6875 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -212,7 +212,7 @@
 /*
  * fill in the superblock
  */
-static int afs_fill_super(struct super_block *sb, void *data, int silent)
+static int afs_fill_super(struct super_block *sb, void *data)
 {
 	struct afs_mount_params *params = data;
 	struct afs_super_info *as = NULL;
@@ -319,17 +319,23 @@
 		goto error;
 	}
 
-	sb->s_flags = flags;
-
-	ret = afs_fill_super(sb, &params, flags & MS_SILENT ? 1 : 0);
-	if (ret < 0) {
-		up_write(&sb->s_umount);
-		deactivate_super(sb);
-		goto error;
+	if (!sb->s_root) {
+		/* initial superblock/root creation */
+		_debug("create");
+		sb->s_flags = flags;
+		ret = afs_fill_super(sb, &params);
+		if (ret < 0) {
+			up_write(&sb->s_umount);
+			deactivate_super(sb);
+			goto error;
+		}
+		sb->s_flags |= MS_ACTIVE;
+	} else {
+		_debug("reuse");
+		ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
 	}
-	sb->s_flags |= MS_ACTIVE;
-	simple_set_mnt(mnt, sb);
 
+	simple_set_mnt(mnt, sb);
 	afs_put_volume(params.volume);
 	afs_put_cell(params.default_cell);
 	_leave(" = 0 [%p]", sb);