ocfs2: fix a tiny race when truncate dio orohaned entry

Once dio crashed it will leave an entry in orphan dir.  And orphan scan
will take care of the clean up.  There is a tiny race case that the same
entry will be truncated twice and then trigger the BUG in
ocfs2_del_inode_from_orphan.

Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ocfs2/aops.c

@@ -925,13 +925,23 @@ clean_orphan:
 		int update_isize = written > 0 ? 1 : 0;
 		loff_t end = update_isize ? offset + written : 0;
 
-		tmp_ret = ocfs2_del_inode_from_orphan(osb, inode,
+		tmp_ret = ocfs2_inode_lock(inode, &di_bh, 1);
+		if (tmp_ret < 0) {
+			ret = tmp_ret;
+			mlog_errno(ret);
+			goto out;
+		}
+
+		tmp_ret = ocfs2_del_inode_from_orphan(osb, inode, di_bh,
 				update_isize, end);
 		if (tmp_ret < 0) {
 			ret = tmp_ret;
+			mlog_errno(ret);
 			goto out;
 		}
 
+		ocfs2_inode_unlock(inode, 1);
+
 		tmp_ret = jbd2_journal_force_commit(journal);
 		if (tmp_ret < 0) {
 			ret = tmp_ret;

fs/ocfs2/journal.c

@@ -2137,6 +2137,8 @@ static int ocfs2_recover_orphans(struct ocfs2_super *osb,
 	struct inode *inode = NULL;
 	struct inode *iter;
 	struct ocfs2_inode_info *oi;
+	struct buffer_head *di_bh = NULL;
+	struct ocfs2_dinode *di = NULL;
 
 	trace_ocfs2_recover_orphans(slot);
 
@@ -2157,16 +2159,22 @@ static int ocfs2_recover_orphans(struct ocfs2_super *osb,
 		iter = oi->ip_next_orphan;
 		oi->ip_next_orphan = NULL;
 
+		ret = ocfs2_rw_lock(inode, 1);
+		if (ret < 0) {
+			mlog_errno(ret);
+			goto next;
+		}
 		/*
 		 * We need to take and drop the inode lock to
 		 * force read inode from disk.
 		 */
-		ret = ocfs2_inode_lock(inode, NULL, 0);
+		ret = ocfs2_inode_lock(inode, &di_bh, 1);
 		if (ret) {
 			mlog_errno(ret);
-			goto next;
+			goto unlock_rw;
 		}
-		ocfs2_inode_unlock(inode, 0);
+
+		di = (struct ocfs2_dinode *)di_bh->b_data;
 
 		if (inode->i_nlink == 0) {
 			spin_lock(&oi->ip_lock);
@@ -2174,43 +2182,30 @@ static int ocfs2_recover_orphans(struct ocfs2_super *osb,
 			 * ocfs2_delete_inode. */
 			oi->ip_flags |= OCFS2_INODE_MAYBE_ORPHANED;
 			spin_unlock(&oi->ip_lock);
-		} else if (orphan_reco_type == ORPHAN_NEED_TRUNCATE) {
-			struct buffer_head *di_bh = NULL;
-
-			ret = ocfs2_rw_lock(inode, 1);
-			if (ret) {
-				mlog_errno(ret);
-				goto next;
-			}
-
-			ret = ocfs2_inode_lock(inode, &di_bh, 1);
-			if (ret < 0) {
-				ocfs2_rw_unlock(inode, 1);
-				mlog_errno(ret);
-				goto next;
-			}
-
+		} else if ((orphan_reco_type == ORPHAN_NEED_TRUNCATE) &&
+				(di->i_flags & cpu_to_le32(OCFS2_DIO_ORPHANED_FL))) {
 			ret = ocfs2_truncate_file(inode, di_bh,
 					i_size_read(inode));
-			ocfs2_inode_unlock(inode, 1);
-			ocfs2_rw_unlock(inode, 1);
-			brelse(di_bh);
 			if (ret < 0) {
 				if (ret != -ENOSPC)
 					mlog_errno(ret);
-				goto next;
+				goto unlock_inode;
 			}
 
-			ret = ocfs2_del_inode_from_orphan(osb, inode, 0, 0);
+			ret = ocfs2_del_inode_from_orphan(osb, inode, di_bh, 0, 0);
 			if (ret)
 				mlog_errno(ret);
 
 			wake_up(&OCFS2_I(inode)->append_dio_wq);
 		} /* else if ORPHAN_NO_NEED_TRUNCATE, do nothing */
-
+unlock_inode:
+		ocfs2_inode_unlock(inode, 1);
+unlock_rw:
+		ocfs2_rw_unlock(inode, 1);
 next:
 		iput(inode);
-
+		brelse(di_bh);
+		di_bh = NULL;
 		inode = iter;
 	}
 

fs/ocfs2/namei.c

@@ -2670,30 +2670,22 @@ bail:
 }
 
 int ocfs2_del_inode_from_orphan(struct ocfs2_super *osb,
-		struct inode *inode, int update_isize,
-		loff_t end)
+		struct inode *inode, struct buffer_head *di_bh,
+		int update_isize, loff_t end)
 {
 	struct inode *orphan_dir_inode = NULL;
 	struct buffer_head *orphan_dir_bh = NULL;
-	struct buffer_head *di_bh = NULL;
-	struct ocfs2_dinode *di = NULL;
+	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
 	handle_t *handle = NULL;
 	int status = 0;
 
-	status = ocfs2_inode_lock(inode, &di_bh, 1);
-	if (status < 0) {
-		mlog_errno(status);
-		goto bail;
-	}
-	di = (struct ocfs2_dinode *) di_bh->b_data;
-
 	orphan_dir_inode = ocfs2_get_system_file_inode(osb,
 			ORPHAN_DIR_SYSTEM_INODE,
 			le16_to_cpu(di->i_dio_orphaned_slot));
 	if (!orphan_dir_inode) {
 		status = -ENOENT;
 		mlog_errno(status);
-		goto bail_unlock_inode;
+		goto bail;
 	}
 
 	mutex_lock(&orphan_dir_inode->i_mutex);
@@ -2702,7 +2694,7 @@ int ocfs2_del_inode_from_orphan(struct ocfs2_super *osb,
 		mutex_unlock(&orphan_dir_inode->i_mutex);
 		iput(orphan_dir_inode);
 		mlog_errno(status);
-		goto bail_unlock_inode;
+		goto bail;
 	}
 
 	handle = ocfs2_start_trans(osb,
@@ -2749,10 +2741,6 @@ bail_unlock_orphan:
 	brelse(orphan_dir_bh);
 	iput(orphan_dir_inode);
 
-bail_unlock_inode:
-	ocfs2_inode_unlock(inode, 1);
-	brelse(di_bh);
-
 bail:
 	return status;
 }

fs/ocfs2/namei.h

@@ -42,8 +42,8 @@ int ocfs2_create_inode_in_orphan(struct inode *dir,
 int ocfs2_add_inode_to_orphan(struct ocfs2_super *osb,
 		struct inode *inode);
 int ocfs2_del_inode_from_orphan(struct ocfs2_super *osb,
-		struct inode *inode, int update_isize,
-		loff_t end);
+		struct inode *inode, struct buffer_head *di_bh,
+		int update_isize, loff_t end);
 int ocfs2_mv_orphaned_inode_to_new(struct inode *dir,
 				   struct inode *new_inode,
 				   struct dentry *new_dentry);