ceph: flush dirty caps of unlinked inode ASAP

Client should release unlinked inode from its cache ASAP. But client
can't release inode with dirty caps.

Link: http://tracker.ceph.com/issues/22886Signed-off-by: Zhi Zhang <zhang.david2011@gmail.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/caps.c

@@ -3964,6 +3964,32 @@ void ceph_put_fmode(struct ceph_inode_info *ci, int fmode)
 		ceph_check_caps(ci, 0, NULL);
 }
 
+/*
+ * For a soon-to-be unlinked file, drop the AUTH_RDCACHE caps. If it
+ * looks like the link count will hit 0, drop any other caps (other
+ * than PIN) we don't specifically want (due to the file still being
+ * open).
+ */
+int ceph_drop_caps_for_unlink(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int drop = CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL;
+
+	spin_lock(&ci->i_ceph_lock);
+	if (inode->i_nlink == 1) {
+		drop |= ~(__ceph_caps_wanted(ci) | CEPH_CAP_PIN);
+
+		ci->i_ceph_flags |= CEPH_I_NODELAY;
+		if (__ceph_caps_dirty(ci)) {
+			struct ceph_mds_client *mdsc =
+				ceph_inode_to_client(inode)->mdsc;
+			__cap_delay_requeue_front(mdsc, ci);
+		}
+	}
+	spin_unlock(&ci->i_ceph_lock);
+	return drop;
+}
+
 /*
  * Helpers for embedding cap and dentry lease releases into mds
  * requests.

fs/ceph/dir.c

@@ -1002,26 +1002,6 @@ static int ceph_link(struct dentry *old_dentry, struct inode *dir,
 	return err;
 }
 
-/*
- * For a soon-to-be unlinked file, drop the AUTH_RDCACHE caps.  If it
- * looks like the link count will hit 0, drop any other caps (other
- * than PIN) we don't specifically want (due to the file still being
- * open).
- */
-static int drop_caps_for_unlink(struct inode *inode)
-{
-	struct ceph_inode_info *ci = ceph_inode(inode);
-	int drop = CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL;
-
-	spin_lock(&ci->i_ceph_lock);
-	if (inode->i_nlink == 1) {
-		drop |= ~(__ceph_caps_wanted(ci) | CEPH_CAP_PIN);
-		ci->i_ceph_flags |= CEPH_I_NODELAY;
-	}
-	spin_unlock(&ci->i_ceph_lock);
-	return drop;
-}
-
 /*
  * rmdir and unlink are differ only by the metadata op code
  */
@@ -1056,7 +1036,7 @@ static int ceph_unlink(struct inode *dir, struct dentry *dentry)
 	set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 	req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
-	req->r_inode_drop = drop_caps_for_unlink(inode);
+	req->r_inode_drop = ceph_drop_caps_for_unlink(inode);
 	err = ceph_mdsc_do_request(mdsc, dir, req);
 	if (!err && !req->r_reply_info.head->is_dentry)
 		d_delete(dentry);
@@ -1104,8 +1084,10 @@ static int ceph_rename(struct inode *old_dir, struct dentry *old_dentry,
 	req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 	/* release LINK_RDCACHE on source inode (mds will lock it) */
 	req->r_old_inode_drop = CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL;
-	if (d_really_is_positive(new_dentry))
-		req->r_inode_drop = drop_caps_for_unlink(d_inode(new_dentry));
+	if (d_really_is_positive(new_dentry)) {
+		req->r_inode_drop =
+			ceph_drop_caps_for_unlink(d_inode(new_dentry));
+	}
 	err = ceph_mdsc_do_request(mdsc, old_dir, req);
 	if (!err && !req->r_reply_info.head->is_dentry) {
 		/*

fs/ceph/super.h

@@ -987,7 +987,7 @@ extern void ceph_check_caps(struct ceph_inode_info *ci, int flags,
 			    struct ceph_mds_session *session);
 extern void ceph_check_delayed_caps(struct ceph_mds_client *mdsc);
 extern void ceph_flush_dirty_caps(struct ceph_mds_client *mdsc);
-
+extern int  ceph_drop_caps_for_unlink(struct inode *inode);
 extern int ceph_encode_inode_release(void **p, struct inode *inode,
 				     int mds, int drop, int unless, int force);
 extern int ceph_encode_dentry_release(void **p, struct dentry *dn,