Commit 8dc15b7a authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Carlos Maiolino
Browse files

xfs: fix XFS_ERRTAG_FORCE_ZERO_RANGE for zoned file system 



The new XFS_ERRTAG_FORCE_ZERO_RANGE error tag added by commit
ea9989668081 ("xfs: error tag to force zeroing on debug kernels") fails
to account for the zoned space reservation rules and this reliably fails
xfs/131 because the zeroing operation returns -EIO.

Fix this by reserving enough space to zero the entire range, which
requires a bit of (fairly ugly) reshuffling to do the error injection
early enough to affect the space reservation.

Fixes: ea9989668081 ("xfs: error tag to force zeroing on debug kernels")
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
Reviewed-by: default avatarCarlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: default avatarCarlos Maiolino <cem@kernel.org>
parent fc40459d

fs/xfs/xfs_file.c

+48 −10
Original line number Diff line number Diff line
@@ -1240,6 +1240,38 @@ xfs_falloc_insert_range( 
	return xfs_insert_file_space(XFS_I(inode), offset, len);

}



/*

 * For various operations we need to zero up to one block at each end of

 * the affected range.  For zoned file systems this will require a space

 * allocation, for which we need a reservation ahead of time.

 */

#define XFS_ZONED_ZERO_EDGE_SPACE_RES		2



/*

 * Zero range implements a full zeroing mechanism but is only used in limited

 * situations. It is more efficient to allocate unwritten extents than to

 * perform zeroing here, so use an errortag to randomly force zeroing on DEBUG

 * kernels for added test coverage.

 *

 * On zoned file systems, the error is already injected by

 * xfs_file_zoned_fallocate, which then reserves the additional space needed.

 * We only check for this extra space reservation here.

 */

static inline bool

xfs_falloc_force_zero(

	struct xfs_inode		*ip,

	struct xfs_zone_alloc_ctx	*ac)

{

	if (xfs_is_zoned_inode(ip)) {

		if (ac->reserved_blocks > XFS_ZONED_ZERO_EDGE_SPACE_RES) {

			ASSERT(IS_ENABLED(CONFIG_XFS_DEBUG));

			return true;

		}

		return false;

	}

	return XFS_TEST_ERROR(ip->i_mount, XFS_ERRTAG_FORCE_ZERO_RANGE);

}



/*

 * Punch a hole and prealloc the range.  We use a hole punch rather than

 * unwritten extent conversion for two reasons:
@@ -1268,14 +1300,7 @@ xfs_falloc_zero_range( 
	if (error)

		return error;



	/*

	 * Zero range implements a full zeroing mechanism but is only used in

	 * limited situations. It is more efficient to allocate unwritten

	 * extents than to perform zeroing here, so use an errortag to randomly

	 * force zeroing on DEBUG kernels for added test coverage.

	 */

	if (XFS_TEST_ERROR(ip->i_mount,

			   XFS_ERRTAG_FORCE_ZERO_RANGE)) {

	if (xfs_falloc_force_zero(ip, ac)) {

		error = xfs_zero_range(ip, offset, len, ac, NULL);

	} else {

		error = xfs_free_file_space(ip, offset, len, ac);
@@ -1423,13 +1448,26 @@ xfs_file_zoned_fallocate( 
{

	struct xfs_zone_alloc_ctx ac = { };

	struct xfs_inode	*ip = XFS_I(file_inode(file));

	struct xfs_mount	*mp = ip->i_mount;

	xfs_filblks_t		count_fsb;

	int			error;



	error = xfs_zoned_space_reserve(ip->i_mount, 2, XFS_ZR_RESERVED, &ac);

	/*

	 * If full zeroing is forced by the error injection knob, we need a

	 * space reservation that covers the entire range.  See the comment in

	 * xfs_zoned_write_space_reserve for the rationale for the calculation.

	 * Otherwise just reserve space for the two boundary blocks.

	 */

	count_fsb = XFS_ZONED_ZERO_EDGE_SPACE_RES;

	if ((mode & FALLOC_FL_MODE_MASK) == FALLOC_FL_ZERO_RANGE &&

	    XFS_TEST_ERROR(mp, XFS_ERRTAG_FORCE_ZERO_RANGE))

		count_fsb += XFS_B_TO_FSB(mp, len) + 1;



	error = xfs_zoned_space_reserve(mp, count_fsb, XFS_ZR_RESERVED, &ac);

	if (error)

		return error;

	error = __xfs_file_fallocate(file, mode, offset, len, &ac);

	xfs_zoned_space_unreserve(ip->i_mount, &ac);

	xfs_zoned_space_unreserve(mp, &ac);

	return error;

}