From: Darrick J. Wong <djwong@xxxxxxxxxx>
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: e50ec7fac81aa2 ("xfs: enable fsmap reporting for internal RT devices")
Signed-off-by: "Darrick J. Wong" <djwong@xxxxxxxxxx>
---
fs/xfs/xfs_fsmap.c | 51 +++++++++++++++++++++++++++++++++------------------
1 file changed, 33 insertions(+), 18 deletions(-)
diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c
index a4bc1642fe5615..414b27a8645886 100644
--- a/fs/xfs/xfs_fsmap.c
+++ b/fs/xfs/xfs_fsmap.c
@@ -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;
+ /*
+ * 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;
}
- /* Fabricate an rmap entry for space occupied by the data dev */
- error = xfs_getfsmap_helper(tp, info, &frec);
- if (error)
- return error;
+ /* 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, rtstart_daddr + keys[0].fmr_physical);
- end_rtb = xfs_daddr_to_rtb(mp, rtstart_daddr +
- min(eofs - 1, keys[1].fmr_physical));
-
+ 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) {
