1 files changed, 106 insertions, 23 deletions

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index b376ebe..ded129d 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2798,39 +2798,80 @@ out_trans_abort:
 }
 
 /*
+ * xfs_rename_alloc_whiteout()
+ *
+ * Return a referenced, unlinked, unlocked inode that that can be used as a
+ * whiteout in a rename transaction. We use a tmpfile inode here so that if we
+ * crash between allocating the inode and linking it into the rename transaction
+ * recovery will free the inode and we won't leak it.
+ */
+static int
+xfs_rename_alloc_whiteout(
+	struct xfs_inode	*dp,
+	struct xfs_inode	**wip)
+{
+	struct xfs_inode	*tmpfile;
+	int			error;
+
+	error = xfs_create_tmpfile(dp, NULL, S_IFCHR | WHITEOUT_MODE, &tmpfile);
+	if (error)
+		return error;
+
+	/* Satisfy xfs_bumplink that this is a real tmpfile */
+	xfs_finish_inode_setup(tmpfile);
+	VFS_I(tmpfile)->i_state |= I_LINKABLE;
+
+	*wip = tmpfile;
+	return 0;
+}
+
+/*
  * xfs_rename
  */
 int
 xfs_rename(
-	xfs_inode_t	*src_dp,
-	struct xfs_name	*src_name,
-	xfs_inode_t	*src_ip,
-	xfs_inode_t	*target_dp,
-	struct xfs_name	*target_name,
-	xfs_inode_t	*target_ip,
-	unsigned int	flags)
+	struct xfs_inode	*src_dp,
+	struct xfs_name		*src_name,
+	struct xfs_inode	*src_ip,
+	struct xfs_inode	*target_dp,
+	struct xfs_name		*target_name,
+	struct xfs_inode	*target_ip,
+	unsigned int		flags)
 {
-	xfs_trans_t	*tp = NULL;
-	xfs_mount_t	*mp = src_dp->i_mount;
-	int		new_parent;		/* moving to a new dir */
-	int		src_is_directory;	/* src_name is a directory */
-	int		error;
-	xfs_bmap_free_t free_list;
-	xfs_fsblock_t   first_block;
-	int		cancel_flags = 0;
-	xfs_inode_t	*inodes[__XFS_SORT_INODES];
-	int		num_inodes = __XFS_SORT_INODES;
-	int		spaceres;
+	struct xfs_mount	*mp = src_dp->i_mount;
+	struct xfs_trans	*tp;
+	struct xfs_bmap_free	free_list;
+	xfs_fsblock_t		first_block;
+	struct xfs_inode	*wip = NULL;		/* whiteout inode */
+	struct xfs_inode	*inodes[__XFS_SORT_INODES];
+	int			num_inodes = __XFS_SORT_INODES;
+	int			new_parent = (src_dp != target_dp);
+	int			src_is_directory = S_ISDIR(src_ip->i_d.di_mode);
+	int			cancel_flags = 0;
+	int			spaceres;
+	int			error;
 
 	trace_xfs_rename(src_dp, target_dp, src_name, target_name);
 
 	if ((flags & RENAME_EXCHANGE) && !target_ip)
 		return -EINVAL;
 
-	new_parent = (src_dp != target_dp);
-	src_is_directory = S_ISDIR(src_ip->i_d.di_mode);
+	/*
+	 * If we are doing a whiteout operation, allocate the whiteout inode
+	 * we will be placing at the target and ensure the type is set
+	 * appropriately.
+	 */
+	if (flags & RENAME_WHITEOUT) {
+		ASSERT(!(flags & (RENAME_NOREPLACE | RENAME_EXCHANGE)));
+		error = xfs_rename_alloc_whiteout(target_dp, &wip);
+		if (error)
+			return error;
+
+		/* setup target dirent info as whiteout */
+		src_name->type = XFS_DIR3_FT_CHRDEV;
+	}
 
-	xfs_sort_for_rename(src_dp, target_dp, src_ip, target_ip, NULL,
+	xfs_sort_for_rename(src_dp, target_dp, src_ip, target_ip, wip,
 				inodes, &num_inodes);
 
 	tp = xfs_trans_alloc(mp, XFS_TRANS_RENAME);
@@ -2870,6 +2911,8 @@ xfs_rename(
 	xfs_trans_ijoin(tp, src_ip, XFS_ILOCK_EXCL);
 	if (target_ip)
 		xfs_trans_ijoin(tp, target_ip, XFS_ILOCK_EXCL);
+	if (wip)
+		xfs_trans_ijoin(tp, wip, XFS_ILOCK_EXCL);
 
 	/*
 	 * If we are using project inheritance, we only allow renames
@@ -3019,17 +3062,55 @@ xfs_rename(
 			goto out_trans_abort;
 	}
 
-	error = xfs_dir_removename(tp, src_dp, src_name, src_ip->i_ino,
+	/*
+	 * For whiteouts, we only need to update the source dirent with the
+	 * inode number of the whiteout inode rather than removing it
+	 * altogether.
+	 */
+	if (wip) {
+		error = xfs_dir_replace(tp, src_dp, src_name, wip->i_ino,
 					&first_block, &free_list, spaceres);
+	} else
+		error = xfs_dir_removename(tp, src_dp, src_name, src_ip->i_ino,
+					   &first_block, &free_list, spaceres);
 	if (error)
 		goto out_trans_abort;
 
+	/*
+	 * For whiteouts, we need to bump the link count on the whiteout inode.
+	 * This means that failures all the way up to this point leave the inode
+	 * on the unlinked list and so cleanup is a simple matter of dropping
+	 * the remaining reference to it. If we fail here after bumping the link
+	 * count, we're shutting down the filesystem so we'll never see the
+	 * intermediate state on disk.
+	 */
+	if (wip) {
+		ASSERT(wip->i_d.di_nlink == 0);
+		error = xfs_bumplink(tp, wip);
+		if (error)
+			goto out_trans_abort;
+		error = xfs_iunlink_remove(tp, wip);
+		if (error)
+			goto out_trans_abort;
+		xfs_trans_log_inode(tp, wip, XFS_ILOG_CORE);
+
+		/*
+		 * Now we have a real link, clear the "I'm a tmpfile" state
+		 * flag from the inode so it doesn't accidentally get misused in
+		 * future.
+		 */
+		VFS_I(wip)->i_state &= ~I_LINKABLE;
+	}
+
 	xfs_trans_ichgtime(tp, src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 	xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);
 	if (new_parent)
 		xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
 
-	return xfs_finish_rename(tp, &free_list);
+	error = xfs_finish_rename(tp, &free_list);
+	if (wip)
+		IRELE(wip);
+	return error;
 
 out_trans_abort:
 	cancel_flags |= XFS_TRANS_ABORT;
@@ -3037,6 +3118,8 @@ out_bmap_cancel:
 	xfs_bmap_cancel(&free_list);
 out_trans_cancel:
 	xfs_trans_cancel(tp, cancel_flags);
+	if (wip)
+		IRELE(wip);
 	return error;
 }