[PATCH 13/26] xfs: encode the rtsummary in big endian format

Darrick J. Wong
2024-08-23T00:24:34Z

From: Darrick J. Wong <djwong@kernel.org>

Currently, the ondisk realtime summary file counters are accessed in
units of 32-bit words. There's no endian translation of the contents of
this file, which means that the Bad Things Happen(tm) if you go from
(say) x86 to powerpc. Since we have a new feature flag, let's take the
opportunity to enforce an endianness on the file. Encode the summary
information in big endian format, like most of the rest of the
filesystem.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/libxfs/xfs_format.h | 4 +++-
fs/xfs/libxfs/xfs_rtbitmap.h | 7 +++++++
fs/xfs/scrub/rtsummary.c | 5 +++++
3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 506f5d5ee03fe..cafac42cd51ad 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -725,10 +725,12 @@ union xfs_rtword_raw {

/*
* Realtime summary counts are accessed by the word, which is currently
- * stored in host-endian format.
+ * stored in host-endian format. Starting with the realtime groups feature,
+ * the words are stored in be32 ondisk.
*/
union xfs_suminfo_raw {
__u32 old;
+ __be32 rtg;
};

/*
diff --git a/fs/xfs/libxfs/xfs_rtbitmap.h b/fs/xfs/libxfs/xfs_rtbitmap.h
index 148f7631d7fc2..d36fe2efc56f0 100644
--- a/fs/xfs/libxfs/xfs_rtbitmap.h
+++ b/fs/xfs/libxfs/xfs_rtbitmap.h
@@ -300,6 +300,8 @@ xfs_suminfo_get(
{
union xfs_suminfo_raw *info = xfs_rsumblock_infoptr(args, index);

+ if (xfs_has_rtgroups(args->mp))
+ return be32_to_cpu(info->rtg);
return info->old;
}

@@ -312,6 +314,11 @@ xfs_suminfo_add(
{
union xfs_suminfo_raw *info = xfs_rsumblock_infoptr(args, index);

+ if (xfs_has_rtgroups(args->mp)) {
+ be32_add_cpu(&info->rtg, delta);
+ return be32_to_cpu(info->rtg);
+ }
+
info->old += delta;
return info->old;
}
diff --git a/fs/xfs/scrub/rtsummary.c b/fs/xfs/scrub/rtsummary.c
index 1f01ed9450388..f6779af92d57b 100644
--- a/fs/xfs/scrub/rtsummary.c
+++ b/fs/xfs/scrub/rtsummary.c
@@ -151,6 +151,11 @@ xchk_rtsum_inc(
struct xfs_mount *mp,
union xfs_suminfo_raw *v)
{
+ if (xfs_has_rtgroups(mp)) {
+ be32_add_cpu(&v->rtg, 1);
+ return be32_to_cpu(v->rtg);
+ }
+
v->old += 1;
return v->old;
}