Commit c6f1401b authored by Darrick J. Wong's avatar Darrick J. Wong Committed by Carlos Maiolino
Browse files

xfs: fix fsmap for internal zoned devices 



Filesystems with an internal zoned rt section use xfs_rtblock_t values
that are relative to the start of the data device.  When fsmap reports
on internal rt sections, it reports the space used by the data section
as "OWN_FS".

Unfortunately, the logic for resuming a query isn't quite right, so
xfs/273 fails because it stress-tests GETFSMAP with a single-record
buffer.  If we enter the "report fake space as OWN_FS" block with a
nonzero key[0].fmr_length, we should add that to key[0].fmr_physical
and recheck if we still need to emit the fake record.  We should /not/
just return 0 from the whole function because that prevents all rmap
record iteration.

If we don't enter that block, the resumption is still wrong.
keys[*].fmr_physical is a reflection of what we copied out to userspace
on a previous query, which means that it already accounts for rgstart.
It is not correct to add rtstart_daddr when computing start_rtb or
end_rtb, so stop that.

While we're at it, add a xfs_has_zoned to make it clear that this is a
zoned filesystem thing.

Fixes: e50ec7fa ("xfs: enable fsmap reporting for internal RT devices")
Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarCarlos Maiolino <cem@kernel.org>
parent 1c406526

fs/xfs/xfs_fsmap.c

+33 −18
Original line number Diff line number Diff line
@@ -876,6 +876,7 @@ xfs_getfsmap_rtdev_rmapbt( 
	const struct xfs_fsmap		*keys,

	struct xfs_getfsmap_info	*info)

{

	struct xfs_fsmap		key0 = *keys; /* struct copy */

	struct xfs_mount		*mp = tp->t_mountp;

	struct xfs_rtgroup		*rtg = NULL;

	struct xfs_btree_cur		*bt_cur = NULL;
@@ -887,32 +888,46 @@ xfs_getfsmap_rtdev_rmapbt( 
	int				error = 0;



	eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_rtstart + mp->m_sb.sb_rblocks);

	if (keys[0].fmr_physical >= eofs)

	if (key0.fmr_physical >= eofs)

		return 0;



	/*

	 * On zoned filesystems with an internal rt volume, the volume comes

	 * immediately after the end of the data volume.  However, the

	 * xfs_rtblock_t address space is relative to the start of the data

	 * device, which means that the first @rtstart fsblocks do not actually

	 * point anywhere.  If a fsmap query comes in with the low key starting

	 * below @rtstart, report it as "owned by filesystem".

	 */

	rtstart_daddr = XFS_FSB_TO_BB(mp, mp->m_sb.sb_rtstart);

	if (keys[0].fmr_physical < rtstart_daddr) {

	if (xfs_has_zoned(mp) && key0.fmr_physical < rtstart_daddr) {

		struct xfs_fsmap_irec		frec = {

			.owner			= XFS_RMAP_OWN_FS,

			.len_daddr		= rtstart_daddr,

		};



		/* Adjust the low key if we are continuing from where we left off. */

		if (keys[0].fmr_length > 0) {

			info->low_daddr = keys[0].fmr_physical + keys[0].fmr_length;

			return 0;

		}



		/* Fabricate an rmap entry for space occupied by the data dev */

		/*

		 * Adjust the start of the query range if we're picking up from

		 * a previous round, and only emit the record if we haven't

		 * already gone past.

		 */

		key0.fmr_physical += key0.fmr_length;

		if (key0.fmr_physical < rtstart_daddr) {

			error = xfs_getfsmap_helper(tp, info, &frec);

			if (error)

				return error;



			key0.fmr_physical = rtstart_daddr;

		}



	start_rtb = xfs_daddr_to_rtb(mp, rtstart_daddr + keys[0].fmr_physical);

	end_rtb = xfs_daddr_to_rtb(mp, rtstart_daddr +

			min(eofs - 1, keys[1].fmr_physical));

		/* Zero the other fields to avoid further adjustments. */

		key0.fmr_owner = 0;

		key0.fmr_offset = 0;

		key0.fmr_length = 0;

	}



	start_rtb = xfs_daddr_to_rtb(mp, key0.fmr_physical);

	end_rtb = xfs_daddr_to_rtb(mp, min(eofs - 1, keys[1].fmr_physical));

	info->missing_owner = XFS_FMR_OWN_FREE;



	/*
@@ -920,12 +935,12 @@ xfs_getfsmap_rtdev_rmapbt( 
	 * low to the fsmap low key and max out the high key to the end

	 * of the rtgroup.

	 */

	info->low.rm_offset = XFS_BB_TO_FSBT(mp, keys[0].fmr_offset);

	error = xfs_fsmap_owner_to_rmap(&info->low, &keys[0]);

	info->low.rm_offset = XFS_BB_TO_FSBT(mp, key0.fmr_offset);

	error = xfs_fsmap_owner_to_rmap(&info->low, &key0);

	if (error)

		return error;

	info->low.rm_blockcount = XFS_BB_TO_FSBT(mp, keys[0].fmr_length);

	xfs_getfsmap_set_irec_flags(&info->low, &keys[0]);

	info->low.rm_blockcount = XFS_BB_TO_FSBT(mp, key0.fmr_length);

	xfs_getfsmap_set_irec_flags(&info->low, &key0);



	/* Adjust the low key if we are continuing from where we left off. */

	if (info->low.rm_blockcount == 0) {