ceph: Propagate dentry down to inode_change_ok()

To avoid clearing of capabilities or security related extended
attributes too early, inode_change_ok() will need to take dentry instead
of inode. ceph_setattr() has the dentry easily available but
__ceph_setattr() is also called from ceph_set_acl() where dentry is not
easily available. Luckily that call path does not need inode_change_ok()
to be called anyway. So reorganize functions a bit so that
inode_change_ok() is called only from paths where dentry is available.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/ceph/acl.c

@@ -125,6 +125,11 @@ 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_mode = new_mode;
 		newattrs.ia_valid = ATTR_MODE;