xfs: refactor realtime volume extent validation

Refactor all the open-coded validation of realtime device extents into a
single helper.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

fs/xfs/libxfs/xfs_bmap.c

@@ -6226,20 +6226,13 @@ xfs_bmap_validate_extent(
 	struct xfs_bmbt_irec	*irec)
 {
 	struct xfs_mount	*mp = ip->i_mount;
-	xfs_fsblock_t		endfsb;
-	bool			isrt;
 
-	if (irec->br_startblock + irec->br_blockcount <= irec->br_startblock)
-		return __this_address;
 	if (irec->br_startoff + irec->br_blockcount <= irec->br_startoff)
 		return __this_address;
 
-	isrt = XFS_IS_REALTIME_INODE(ip);
-	endfsb = irec->br_startblock + irec->br_blockcount - 1;
-	if (isrt && whichfork == XFS_DATA_FORK) {
-		if (!xfs_verify_rtbno(mp, irec->br_startblock))
-			return __this_address;
-		if (!xfs_verify_rtbno(mp, endfsb))
+	if (XFS_IS_REALTIME_INODE(ip) && whichfork == XFS_DATA_FORK) {
+		if (!xfs_verify_rtext(mp, irec->br_startblock,
+					  irec->br_blockcount))
 			return __this_address;
 	} else {
 		if (!xfs_verify_fsbext(mp, irec->br_startblock,

fs/xfs/libxfs/xfs_types.c

@@ -198,6 +198,22 @@ xfs_verify_rtbno(
 	return rtbno < mp->m_sb.sb_rblocks;
 }
 
+/* Verify that a realtime device extent is fully contained inside the volume. */
+bool
+xfs_verify_rtext(
+	struct xfs_mount	*mp,
+	xfs_rtblock_t		rtbno,
+	xfs_rtblock_t		len)
+{
+	if (rtbno + len <= rtbno)
+		return false;
+
+	if (!xfs_verify_rtbno(mp, rtbno))
+		return false;
+
+	return xfs_verify_rtbno(mp, rtbno + len - 1);
+}
+
 /* Calculate the range of valid icount values. */
 void
 xfs_icount_range(

fs/xfs/libxfs/xfs_types.h

@@ -197,6 +197,8 @@ bool xfs_verify_ino(struct xfs_mount *mp, xfs_ino_t ino);
 bool xfs_internal_inum(struct xfs_mount *mp, xfs_ino_t ino);
 bool xfs_verify_dir_ino(struct xfs_mount *mp, xfs_ino_t ino);
 bool xfs_verify_rtbno(struct xfs_mount *mp, xfs_rtblock_t rtbno);
+bool xfs_verify_rtext(struct xfs_mount *mp, xfs_rtblock_t rtbno,
+		xfs_rtblock_t len);
 bool xfs_verify_icount(struct xfs_mount *mp, unsigned long long icount);
 bool xfs_verify_dablk(struct xfs_mount *mp, xfs_fileoff_t off);
 void xfs_icount_range(struct xfs_mount *mp, unsigned long long *min,

fs/xfs/scrub/bmap.c

@@ -319,7 +319,6 @@ xchk_bmap_iextent(
 	struct xfs_bmbt_irec	*irec)
 {
 	struct xfs_mount	*mp = info->sc->mp;
-	xfs_filblks_t		end;
 	int			error = 0;
 
 	/*
@@ -349,13 +348,8 @@ xchk_bmap_iextent(
 	if (irec->br_blockcount > MAXEXTLEN)
 		xchk_fblock_set_corrupt(info->sc, info->whichfork,
 				irec->br_startoff);
-	if (irec->br_startblock + irec->br_blockcount <= irec->br_startblock)
-		xchk_fblock_set_corrupt(info->sc, info->whichfork,
-				irec->br_startoff);
-	end = irec->br_startblock + irec->br_blockcount - 1;
 	if (info->is_rt &&
-	    (!xfs_verify_rtbno(mp, irec->br_startblock) ||
-	     !xfs_verify_rtbno(mp, end)))
+	    !xfs_verify_rtext(mp, irec->br_startblock, irec->br_blockcount))
 		xchk_fblock_set_corrupt(info->sc, info->whichfork,
 				irec->br_startoff);
 	if (!info->is_rt &&

fs/xfs/scrub/rtbitmap.c

@@ -52,9 +52,7 @@ xchk_rtbitmap_rec(
 	startblock = rec->ar_startext * tp->t_mountp->m_sb.sb_rextsize;
 	blockcount = rec->ar_extcount * tp->t_mountp->m_sb.sb_rextsize;
 
-	if (startblock + blockcount <= startblock ||
-	    !xfs_verify_rtbno(sc->mp, startblock) ||
-	    !xfs_verify_rtbno(sc->mp, startblock + blockcount - 1))
+	if (!xfs_verify_rtext(sc->mp, startblock, blockcount))
 		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
 	return 0;
 }