ceph: add refcounting for Fx caps

In future patches we'll be taking and relying on Fx caps. Add proper
refcounting for them.
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Reviewed-by: N"Yan, Zheng" <zyan@redhat.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

fs/ceph/caps.c

@@ -965,6 +965,8 @@ int __ceph_caps_used(struct ceph_inode_info *ci)
 		used |= CEPH_CAP_FILE_WR;
 	if (ci->i_wb_ref || ci->i_wrbuffer_ref)
 		used |= CEPH_CAP_FILE_BUFFER;
+	if (ci->i_fx_ref)
+		used |= CEPH_CAP_FILE_EXCL;
 	return used;
 }
 
@@ -2500,6 +2502,8 @@ static void __take_cap_refs(struct ceph_inode_info *ci, int got,
 		ci->i_rd_ref++;
 	if (got & CEPH_CAP_FILE_CACHE)
 		ci->i_rdcache_ref++;
+	if (got & CEPH_CAP_FILE_EXCL)
+		ci->i_fx_ref++;
 	if (got & CEPH_CAP_FILE_WR) {
 		if (ci->i_wr_ref == 0 && !ci->i_head_snapc) {
 			BUG_ON(!snap_rwsem_locked);
@@ -2911,6 +2915,9 @@ void ceph_put_cap_refs(struct ceph_inode_info *ci, int had)
 	if (had & CEPH_CAP_FILE_CACHE)
 		if (--ci->i_rdcache_ref == 0)
 			last++;
+	if (had & CEPH_CAP_FILE_EXCL)
+		if (--ci->i_fx_ref == 0)
+			last++;
 	if (had & CEPH_CAP_FILE_BUFFER) {
 		if (--ci->i_wb_ref == 0) {
 			last++;

fs/ceph/inode.c

@@ -496,6 +496,7 @@ struct inode *ceph_alloc_inode(struct super_block *sb)
 	ci->i_rdcache_ref = 0;
 	ci->i_wr_ref = 0;
 	ci->i_wb_ref = 0;
+	ci->i_fx_ref = 0;
 	ci->i_wrbuffer_ref = 0;
 	ci->i_wrbuffer_ref_head = 0;
 	atomic_set(&ci->i_filelock_ref, 0);

fs/ceph/super.h

@@ -375,7 +375,7 @@ struct ceph_inode_info {
 
 	/* held references to caps */
 	int i_pin_ref;
-	int i_rd_ref, i_rdcache_ref, i_wr_ref, i_wb_ref;
+	int i_rd_ref, i_rdcache_ref, i_wr_ref, i_wb_ref, i_fx_ref;
 	int i_wrbuffer_ref, i_wrbuffer_ref_head;
 	atomic_t i_filelock_ref;
 	atomic_t i_shared_gen;       /* increment each time we get FILE_SHARED */