ceph: track primary dentry link

Newer versions of the MDS will flag a dentry as "primary". In later
patches, we'll need to consult this info, so track it in di->flags.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/dir.c

@@ -1411,6 +1411,7 @@ void ceph_invalidate_dentry_lease(struct dentry *dentry)
 	spin_lock(&dentry->d_lock);
 	di->time = jiffies;
 	di->lease_shared_gen = 0;
+	di->flags &= ~CEPH_DENTRY_PRIMARY_LINK;
 	__dentry_lease_unlist(di);
 	spin_unlock(&dentry->d_lock);
 }

fs/ceph/inode.c

@@ -1051,6 +1051,7 @@ static void __update_dentry_lease(struct inode *dir, struct dentry *dentry,
 				  struct ceph_mds_session **old_lease_session)
 {
 	struct ceph_dentry_info *di = ceph_dentry(dentry);
+	unsigned mask = le16_to_cpu(lease->mask);
 	long unsigned duration = le32_to_cpu(lease->duration_ms);
 	long unsigned ttl = from_time + (duration * HZ) / 1000;
 	long unsigned half_ttl = from_time + (duration * HZ / 2) / 1000;
@@ -1062,8 +1063,13 @@ static void __update_dentry_lease(struct inode *dir, struct dentry *dentry,
 	if (ceph_snap(dir) != CEPH_NOSNAP)
 		return;
 
+	if (mask & CEPH_LEASE_PRIMARY_LINK)
+		di->flags |= CEPH_DENTRY_PRIMARY_LINK;
+	else
+		di->flags &= ~CEPH_DENTRY_PRIMARY_LINK;
+
 	di->lease_shared_gen = atomic_read(&ceph_inode(dir)->i_shared_gen);
-	if (duration == 0) {
+	if (!(mask & CEPH_LEASE_VALID)) {
 		__ceph_dentry_dir_lease_touch(di);
 		return;
 	}

fs/ceph/super.h

@@ -284,6 +284,7 @@ struct ceph_dentry_info {
 #define CEPH_DENTRY_REFERENCED		1
 #define CEPH_DENTRY_LEASE_LIST		2
 #define CEPH_DENTRY_SHRINK_LIST		4
+#define CEPH_DENTRY_PRIMARY_LINK	8
 
 struct ceph_inode_xattrs_info {
 	/*

include/linux/ceph/ceph_fs.h

@@ -531,6 +531,9 @@ struct ceph_mds_reply_lease {
 	__le32 seq;
 } __attribute__ ((packed));
 
+#define CEPH_LEASE_VALID        (1 | 2) /* old and new bit values */
+#define CEPH_LEASE_PRIMARY_LINK 4       /* primary linkage */
+
 struct ceph_mds_reply_dirfrag {
 	__le32 frag;            /* fragment */
 	__le32 auth;            /* auth mds, if this is a delegation point */