ceph: use i_release_count to indicate dir's completeness

Current ceph code tracks directory's completeness in two places.
ceph_readdir() checks i_release_count to decide if it can set the
I_COMPLETE flag in i_ceph_flags. All other places check the I_COMPLETE
flag. This indirection introduces locking complexity.

This patch adds a new variable i_complete_count to ceph_inode_info.
Set i_release_count's value to it when marking a directory complete.
By comparing the two variables, we know if a directory is complete

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index bc575a4..f956310 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -490,7 +490,7 @@
 		ci->i_rdcache_gen++;
 
 	/*
-	 * if we are newly issued FILE_SHARED, clear I_COMPLETE; we
+	 * if we are newly issued FILE_SHARED, mark dir not complete; we
 	 * don't know what happened to this directory while we didn't
 	 * have the cap.
 	 */
@@ -499,7 +499,7 @@
 		ci->i_shared_gen++;
 		if (S_ISDIR(ci->vfs_inode.i_mode)) {
 			dout(" marking %p NOT complete\n", &ci->vfs_inode);
-			ci->i_ceph_flags &= ~CEPH_I_COMPLETE;
+			__ceph_dir_clear_complete(ci);
 		}
 	}
 }