ceph: make lease code DN specific

The lease code includes a mask in the CEPH_LOCK_* namespace, but that
namespace is changing, and only one mask (formerly _DN == 1) is used, so
hard code for that value for now.

If we ever extend this code to handle leases over different data types we
can extend it accordingly.
Signed-off-by: Sage Weil <sage@newdream.net>

fs/ceph/ceph_fs.h

@@ -265,16 +265,17 @@ extern const char *ceph_mds_state_name(int s);
  *  - they also define the lock ordering by the MDS
  *  - a few of these are internal to the mds
  */
-#define CEPH_LOCK_DN          1
-#define CEPH_LOCK_ISNAP       2
-#define CEPH_LOCK_IVERSION    4     /* mds internal */
-#define CEPH_LOCK_IFILE       8     /* mds internal */
-#define CEPH_LOCK_IAUTH       32
-#define CEPH_LOCK_ILINK       64
-#define CEPH_LOCK_IDFT        128   /* dir frag tree */
-#define CEPH_LOCK_INEST       256   /* mds internal */
-#define CEPH_LOCK_IXATTR      512
-#define CEPH_LOCK_INO         2048  /* immutable inode bits; not a lock */
+#define CEPH_LOCK_DVERSION    1
+#define CEPH_LOCK_DN          2
+#define CEPH_LOCK_ISNAP       16
+#define CEPH_LOCK_IVERSION    32    /* mds internal */
+#define CEPH_LOCK_IFILE       64
+#define CEPH_LOCK_IAUTH       128
+#define CEPH_LOCK_ILINK       256
+#define CEPH_LOCK_IDFT        512   /* dir frag tree */
+#define CEPH_LOCK_INEST       1024  /* mds internal */
+#define CEPH_LOCK_IXATTR      2048
+#define CEPH_LOCK_INO         8192  /* immutable inode bits; not a lock */
 
 /* client_session ops */
 enum {

fs/ceph/mds_client.c

@@ -2541,7 +2541,7 @@ void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
 		return;
 	lease = msg->front.iov_base;
 	lease->action = action;
-	lease->mask = cpu_to_le16(CEPH_LOCK_DN);
+	lease->mask = cpu_to_le16(1);
 	lease->ino = cpu_to_le64(ceph_vino(inode).ino);
 	lease->first = lease->last = cpu_to_le64(ceph_vino(inode).snap);
 	lease->seq = cpu_to_le32(seq);
@@ -2571,7 +2571,7 @@ void ceph_mdsc_lease_release(struct ceph_mds_client *mdsc, struct inode *inode,
 
 	BUG_ON(inode == NULL);
 	BUG_ON(dentry == NULL);
-	BUG_ON(mask != CEPH_LOCK_DN);
+	BUG_ON(mask == 0);
 
 	/* is dentry lease valid? */
 	spin_lock(&dentry->d_lock);