From: Darrick J. Wong <djwong@xxxxxxxxxx>
Currently, the ondisk realtime bitmap file is 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.
The natural format of a bitmap is (IMHO) little endian, because the byte
offsets of the bitmap data should always increase in step with the
information being indexed.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
libxfs/xfs_format.h | 4 +++-
libxfs/xfs_rtbitmap.c | 8 +++++++-
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/libxfs/xfs_format.h b/libxfs/xfs_format.h
index 4096d3f069a..c7752aaa447 100644
--- a/libxfs/xfs_format.h
+++ b/libxfs/xfs_format.h
@@ -738,10 +738,12 @@ struct xfs_agfl {
/*
* Realtime bitmap information is 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 le32 ondisk.
*/
union xfs_rtword_ondisk {
__u32 raw;
+ __le32 rtg;
};
/*
diff --git a/libxfs/xfs_rtbitmap.c b/libxfs/xfs_rtbitmap.c
index 2e286a22196..db80f740151 100644
--- a/libxfs/xfs_rtbitmap.c
+++ b/libxfs/xfs_rtbitmap.c
@@ -173,6 +173,9 @@ xfs_rtbitmap_getword(
struct xfs_mount *mp,
union xfs_rtword_ondisk *wordptr)
{
+ if (xfs_has_rtgroups(mp))
+ return le32_to_cpu(wordptr->rtg);
+
return wordptr->raw;
}
@@ -183,7 +186,10 @@ xfs_rtbitmap_setword(
union xfs_rtword_ondisk *wordptr,
xfs_rtword_t incore)
{
- wordptr->raw = incore;
+ if (xfs_has_rtgroups(mp))
+ wordptr->rtg = cpu_to_le32(incore);
+ else
+ wordptr->raw = incore;
}
/*
