Commit 85ef08b5 authored by Chandan Babu R's avatar Chandan Babu R Committed by Darrick J. Wong
Browse files

xfs: Check for extent overflow when punching a hole 



The extent mapping the file offset at which a hole has to be
inserted will be split into two extents causing extent count to
increase by 1.

Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarAllison Henderson <allison.henderson@oracle.com>
Signed-off-by: default avatarChandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent 727e1acd

fs/xfs/libxfs/xfs_inode_fork.h

+7 −0
Original line number Diff line number Diff line
@@ -40,6 +40,13 @@ struct xfs_ifork { 
 */

#define XFS_IEXT_ADD_NOSPLIT_CNT	(1)



/*

 * Punching out an extent from the middle of an existing extent can cause the

 * extent count to increase by 1.

 * i.e. | Old extent | Hole | Old extent |

 */

#define XFS_IEXT_PUNCH_HOLE_CNT		(1)



/*

 * Fork handling.

 */

fs/xfs/xfs_bmap_item.c

+9 −6
Original line number Diff line number Diff line
@@ -471,6 +471,7 @@ xfs_bui_item_recover( 
	xfs_exntst_t			state;

	unsigned int			bui_type;

	int				whichfork;

	int				iext_delta;

	int				error = 0;



	if (!xfs_bui_validate(mp, buip)) {
@@ -508,12 +509,14 @@ xfs_bui_item_recover( 
	xfs_ilock(ip, XFS_ILOCK_EXCL);

	xfs_trans_ijoin(tp, ip, 0);



	if (bui_type == XFS_BMAP_MAP) {

		error = xfs_iext_count_may_overflow(ip, whichfork,

				XFS_IEXT_ADD_NOSPLIT_CNT);

	if (bui_type == XFS_BMAP_MAP)

		iext_delta = XFS_IEXT_ADD_NOSPLIT_CNT;

	else

		iext_delta = XFS_IEXT_PUNCH_HOLE_CNT;



	error = xfs_iext_count_may_overflow(ip, whichfork, iext_delta);

	if (error)

		goto err_cancel;

	}



	count = bmap->me_len;

	error = xfs_trans_log_finish_bmap_update(tp, budp, bui_type, ip,

fs/xfs/xfs_bmap_util.c

+10 −0
Original line number Diff line number Diff line
@@ -891,6 +891,11 @@ xfs_unmap_extent( 


	xfs_trans_ijoin(tp, ip, 0);



	error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,

			XFS_IEXT_PUNCH_HOLE_CNT);

	if (error)

		goto out_trans_cancel;



	error = xfs_bunmapi(tp, ip, startoffset_fsb, len_fsb, 0, 2, done);

	if (error)

		goto out_trans_cancel;
@@ -1168,6 +1173,11 @@ xfs_insert_file_space( 
	xfs_ilock(ip, XFS_ILOCK_EXCL);

	xfs_trans_ijoin(tp, ip, 0);



	error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,

			XFS_IEXT_PUNCH_HOLE_CNT);

	if (error)

		goto out_trans_cancel;



	/*

	 * The extent shifting code works on extent granularity. So, if stop_fsb

	 * is not the starting block of extent, we need to split the extent at