xfs: xfs_rtword_t should be unsigned, not signed

xfs_rtword_t is used for bit manipulations in the realtime bitmap file.
Since we're performing bit shifts with this type, we don't want sign
extension and we don't want to be left shifting negative quantities
because that's undefined behavior.

This also shuts up these UBSAN warnings:
UBSAN: Undefined behaviour in fs/xfs/libxfs/xfs_rtbitmap.c:833:48
signed integer overflow:
-2147483648 - 1 cannot be represented in type 'int'

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>

diff --git a/fs/xfs/libxfs/xfs_types.h b/fs/xfs/libxfs/xfs_types.h
index 3c56069..ea18449 100644 (file)
--- a/fs/xfs/libxfs/xfs_types.h
+++ b/fs/xfs/libxfs/xfs_types.h
@@ -30,7 +30,7 @@ typedef int64_t               xfs_fsize_t;    /* bytes in a file */
 typedef uint64_t       xfs_ufsize_t;   /* unsigned bytes in a file */
 
 typedef int32_t                xfs_suminfo_t;  /* type of bitmap summary info */
-typedef int32_t                xfs_rtword_t;   /* word type for bitmap manipulations */
+typedef uint32_t       xfs_rtword_t;   /* word type for bitmap manipulations */
 
 typedef int64_t                xfs_lsn_t;      /* log sequence number */
 typedef int32_t                xfs_tid_t;      /* transaction identifier */