xfs: hoist freeing of rt data fork extent mappings

Currently, xfs_bmap_del_extent_real contains a bunch of code to convert
the physical extent of a data fork mapping for a realtime file into rt
extents and pass that to the rt extent freeing function.  Since the
details of this aren't needed when CONFIG_XFS_REALTIME=n, move it to
xfs_rtbitmap.c to reduce code size when realtime isn't enabled.

This will (one day) enable realtime EFIs to reuse the same
unit-converting call with less code duplication.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/libxfs/xfs_bmap.c

@@ -5057,33 +5057,20 @@ xfs_bmap_del_extent_real(
 
 	flags = XFS_ILOG_CORE;
 	if (whichfork == XFS_DATA_FORK && XFS_IS_REALTIME_INODE(ip)) {
-		xfs_filblks_t	len;
-		xfs_extlen_t	mod;
-
-		len = div_u64_rem(del->br_blockcount, mp->m_sb.sb_rextsize,
-				  &mod);
-		ASSERT(mod == 0);
-
 		if (!(bflags & XFS_BMAPI_REMAP)) {
-			xfs_fsblock_t	bno;
-
-			bno = div_u64_rem(del->br_startblock,
-					mp->m_sb.sb_rextsize, &mod);
-			ASSERT(mod == 0);
-
-			error = xfs_rtfree_extent(tp, bno, (xfs_extlen_t)len);
+			error = xfs_rtfree_blocks(tp, del->br_startblock,
+					del->br_blockcount);
 			if (error)
 				goto done;
 		}
 
 		do_fx = 0;
-		nblks = len * mp->m_sb.sb_rextsize;
 		qfield = XFS_TRANS_DQ_RTBCOUNT;
 	} else {
 		do_fx = 1;
-		nblks = del->br_blockcount;
 		qfield = XFS_TRANS_DQ_BCOUNT;
 	}
+	nblks = del->br_blockcount;
 
 	del_endblock = del->br_startblock + del->br_blockcount;
 	if (cur) {

fs/xfs/libxfs/xfs_rtbitmap.c

@@ -1005,6 +1005,39 @@ xfs_rtfree_extent(
 	return 0;
 }
 
+/*
+ * Free some blocks in the realtime subvolume.  rtbno and rtlen are in units of
+ * rt blocks, not rt extents; must be aligned to the rt extent size; and rtlen
+ * cannot exceed XFS_MAX_BMBT_EXTLEN.
+ */
+int
+xfs_rtfree_blocks(
+	struct xfs_trans	*tp,
+	xfs_fsblock_t		rtbno,
+	xfs_filblks_t		rtlen)
+{
+	struct xfs_mount	*mp = tp->t_mountp;
+	xfs_rtblock_t		bno;
+	xfs_filblks_t		len;
+	xfs_extlen_t		mod;
+
+	ASSERT(rtlen <= XFS_MAX_BMBT_EXTLEN);
+
+	len = div_u64_rem(rtlen, mp->m_sb.sb_rextsize, &mod);
+	if (mod) {
+		ASSERT(mod == 0);
+		return -EIO;
+	}
+
+	bno = div_u64_rem(rtbno, mp->m_sb.sb_rextsize, &mod);
+	if (mod) {
+		ASSERT(mod == 0);
+		return -EIO;
+	}
+
+	return xfs_rtfree_extent(tp, bno, len);
+}
+
 /* Find all the free records within a given range. */
 int
 xfs_rtalloc_query_range(

fs/xfs/xfs_rtalloc.h

@@ -58,6 +58,10 @@ xfs_rtfree_extent(
 	xfs_rtblock_t		bno,	/* starting block number to free */
 	xfs_extlen_t		len);	/* length of extent freed */
 
+/* Same as above, but in units of rt blocks. */
+int xfs_rtfree_blocks(struct xfs_trans *tp, xfs_fsblock_t rtbno,
+		xfs_filblks_t rtlen);
+
 /*
  * Initialize realtime fields in the mount structure.
  */
@@ -139,6 +143,7 @@ int xfs_rtalloc_reinit_frextents(struct xfs_mount *mp);
 #else
 # define xfs_rtallocate_extent(t,b,min,max,l,f,p,rb)    (ENOSYS)
 # define xfs_rtfree_extent(t,b,l)                       (ENOSYS)
+# define xfs_rtfree_blocks(t,rb,rl)			(ENOSYS)
 # define xfs_rtpick_extent(m,t,l,rb)                    (ENOSYS)
 # define xfs_growfs_rt(mp,in)                           (ENOSYS)
 # define xfs_rtalloc_query_range(t,l,h,f,p)             (ENOSYS)