ceph: don't check quota for snap inode

snap inode's i_snap_realm is not pointing to ceph_snap_realm.

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 1f60498..6cd92a0 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -936,7 +936,8 @@
 		goto out;
 	}
 
-	if (ceph_quota_is_max_files_exceeded(dir)) {
+	if (op == CEPH_MDS_OP_MKDIR &&
+	    ceph_quota_is_max_files_exceeded(dir)) {
 		err = -EDQUOT;
 		goto out;
 	}
diff --git a/fs/ceph/quota.c b/fs/ceph/quota.c
index 7d1e18e..529de67 100644
--- a/fs/ceph/quota.c
+++ b/fs/ceph/quota.c
@@ -86,8 +86,15 @@
 	struct ceph_vino vino;
 	struct inode *in;
 
+	if (ceph_snap(inode) != CEPH_NOSNAP)
+		return NULL;
+
 	realm = ceph_inode(inode)->i_snap_realm;
-	ceph_get_snap_realm(mdsc, realm);
+	if (realm)
+		ceph_get_snap_realm(mdsc, realm);
+	else
+		pr_err_ratelimited("get_quota_realm: ino (%llx.%llx) "
+				   "null i_snap_realm\n", ceph_vinop(inode));
 	while (realm) {
 		vino.ino = realm->ino;
 		vino.snap = CEPH_NOSNAP;
@@ -158,9 +165,16 @@
 	bool is_root;
 	bool exceeded = false;
 
+	if (ceph_snap(inode) != CEPH_NOSNAP)
+		return false;
+
 	down_read(&mdsc->snap_rwsem);
 	realm = ceph_inode(inode)->i_snap_realm;
-	ceph_get_snap_realm(mdsc, realm);
+	if (realm)
+		ceph_get_snap_realm(mdsc, realm);
+	else
+		pr_err_ratelimited("check_quota_exceeded: ino (%llx.%llx) "
+				   "null i_snap_realm\n", ceph_vinop(inode));
 	while (realm) {
 		vino.ino = realm->ino;
 		vino.snap = CEPH_NOSNAP;