Commit 0365c5d6 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Dave Chinner
Browse files

xfs: handle zeroing in xfs_file_iomap_begin_delay 



We only need to allocate blocks for zeroing for reflink inodes,
and for we currently have a special case for reflink files in
the otherwise direct I/O path that I'd like to get rid of.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent daa79bae

fs/xfs/xfs_iomap.c

+38 −6
Original line number Diff line number Diff line
@@ -62,6 +62,21 @@ xfs_bmbt_to_iomap( 
	iomap->dax_dev = xfs_find_daxdev_for_inode(VFS_I(ip));

}



static void

xfs_hole_to_iomap(

	struct xfs_inode	*ip,

	struct iomap		*iomap,

	xfs_fileoff_t		offset_fsb,

	xfs_fileoff_t		end_fsb)

{

	iomap->addr = IOMAP_NULL_ADDR;

	iomap->type = IOMAP_HOLE;

	iomap->offset = XFS_FSB_TO_B(ip->i_mount, offset_fsb);

	iomap->length = XFS_FSB_TO_B(ip->i_mount, end_fsb - offset_fsb);

	iomap->bdev = xfs_find_bdev_for_inode(VFS_I(ip));

	iomap->dax_dev = xfs_find_daxdev_for_inode(VFS_I(ip));

}



xfs_extlen_t

xfs_eof_alignment(

	struct xfs_inode	*ip,
@@ -502,6 +517,7 @@ xfs_file_iomap_begin_delay( 
	struct inode		*inode,

	loff_t			offset,

	loff_t			count,

	unsigned		flags,

	struct iomap		*iomap)

{

	struct xfs_inode	*ip = XFS_I(inode);
@@ -538,13 +554,23 @@ xfs_file_iomap_begin_delay( 
			goto out_unlock;

	}



	end_fsb = min(XFS_B_TO_FSB(mp, offset + count), maxbytes_fsb);



	eof = !xfs_iext_lookup_extent(ip, ifp, offset_fsb, &icur, &got);

	if (!eof && got.br_startoff <= offset_fsb) {

		if (xfs_is_reflink_inode(ip)) {

	if (eof)

		got.br_startoff = end_fsb; /* fake hole until the end */



	if (got.br_startoff <= offset_fsb) {

		/*

		 * For reflink files we may need a delalloc reservation when

		 * overwriting shared extents.   This includes zeroing of

		 * existing extents that contain data.

		 */

		if (xfs_is_reflink_inode(ip) &&

		    ((flags & IOMAP_WRITE) ||

		     got.br_state != XFS_EXT_UNWRITTEN)) {

			bool		shared;



			end_fsb = min(XFS_B_TO_FSB(mp, offset + count),

					maxbytes_fsb);

			xfs_trim_extent(&got, offset_fsb, end_fsb - offset_fsb);

			error = xfs_reflink_reserve_cow(ip, &got, &shared);

			if (error)
@@ -555,6 +581,11 @@ xfs_file_iomap_begin_delay( 
		goto done;

	}



	if (flags & IOMAP_ZERO) {

		xfs_hole_to_iomap(ip, iomap, offset_fsb, got.br_startoff);

		goto out_unlock;

	}



	error = xfs_qm_dqattach_locked(ip, false);

	if (error)

		goto out_unlock;
@@ -1009,10 +1040,11 @@ xfs_file_iomap_begin( 
	if (XFS_FORCED_SHUTDOWN(mp))

		return -EIO;



	if (((flags & (IOMAP_WRITE | IOMAP_DIRECT)) == IOMAP_WRITE) &&

	if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && !(flags & IOMAP_DIRECT) &&

			!IS_DAX(inode) && !xfs_get_extsz_hint(ip)) {

		/* Reserve delalloc blocks for regular writeback. */

		return xfs_file_iomap_begin_delay(inode, offset, length, iomap);

		return xfs_file_iomap_begin_delay(inode, offset, length, flags,

				iomap);

	}



	/*