[15/45] xfs: encode the rtsummary in big endian format

Commit Message

Darrick J. Wong Dec. 30, 2022, 10:19 p.m. UTC

From: Darrick J. Wong <[e-mail]>

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 <[e-mail]>
---
 libxfs/xfs_format.h   |    4 +++-
 libxfs/xfs_rtbitmap.c |    8 +++++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

Patch

diff --git a/libxfs/xfs_format.h b/libxfs/xfs_format.h
index 47b2e31e256..7e76bedda68 100644
--- a/libxfs/xfs_format.h
+++ b/libxfs/xfs_format.h
@@ -748,10 +748,12 @@  union xfs_rtword_ondisk {
 
 /*
  * 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_ondisk {
 	__u32		raw;
+	__be32		rtg;
 };
 
 /*
diff --git a/libxfs/xfs_rtbitmap.c b/libxfs/xfs_rtbitmap.c
index 4ed3bd261f6..26428898d60 100644
--- a/libxfs/xfs_rtbitmap.c
+++ b/libxfs/xfs_rtbitmap.c
@@ -558,6 +558,9 @@  xfs_suminfo_get(
 	struct xfs_mount	*mp,
 	union xfs_suminfo_ondisk *infoptr)
 {
+	if (xfs_has_rtgroups(mp))
+		return be32_to_cpu(infoptr->rtg);
+
 	return infoptr->raw;
 }
 
@@ -567,7 +570,10 @@  xfs_suminfo_add(
 	union xfs_suminfo_ondisk *infoptr,
 	int			delta)
 {
-	infoptr->raw += delta;
+	if (xfs_has_rtgroups(mp))
+		be32_add_cpu(&infoptr->rtg, delta);
+	else
+		infoptr->raw += delta;
 }
 
 /*