ceph: check snap first in ceph_set_acl()

Do the snap check first in ceph_set_acl(), so we can avoid
unnecessary operations when the inode has snap.
Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/acl.c

@@ -104,6 +104,11 @@ int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	struct timespec64 old_ctime = inode->i_ctime;
 	umode_t new_mode = inode->i_mode, old_mode = inode->i_mode;
 
+	if (ceph_snap(inode) != CEPH_NOSNAP) {
+		ret = -EROFS;
+		goto out;
+	}
+
 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		name = XATTR_NAME_POSIX_ACL_ACCESS;
@@ -138,11 +143,6 @@ int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 			goto out_free;
 	}
 
-	if (ceph_snap(inode) != CEPH_NOSNAP) {
-		ret = -EROFS;
-		goto out_free;
-	}
-
 	if (new_mode != old_mode) {
 		newattrs.ia_ctime = current_time(inode);
 		newattrs.ia_mode = new_mode;