xfs: refactor rt extent unit conversions [v1.1]

This series replaces all the open-coded integer division and
 multiplication conversions between rt blocks and rt extents with calls
 to static inline helpers.  Having cleaned all that up, the helpers are
 augmented to skip the expensive operations in favor of bit shifts and
 masking if the rt extent size is a power of two.
 
 v1.1: various cleanups suggested by hch
 
 With a bit of luck, this should all go splendidly.
 
 Signed-off-by: Darrick J. Wong <djwong@kernel.org>
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQQ2qTKExjcn+O1o2YRKO3ySh0YRpgUCZTFTEQAKCRBKO3ySh0YR
 pn8VAPwIqtQs6t19YAuIPy+Iwo0xls+G/XWTD+l+rWurtJBGKwD/csGP7Bt0w71i
 UzJ+VhyFUacV4MJdyGCrkGi0tuwUjQU=
 =zyjM
 -----END PGP SIGNATURE-----

Merge tag 'refactor-rt-unit-conversions-6.7_2023-10-19' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.7-mergeA

xfs: refactor rt extent unit conversions [v1.1]

This series replaces all the open-coded integer division and
multiplication conversions between rt blocks and rt extents with calls
to static inline helpers.  Having cleaned all that up, the helpers are
augmented to skip the expensive operations in favor of bit shifts and
masking if the rt extent size is a power of two.

v1.1: various cleanups suggested by hch

With a bit of luck, this should all go splendidly.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

* tag 'refactor-rt-unit-conversions-6.7_2023-10-19' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
  xfs: use shifting and masking when converting rt extents, if possible
  xfs: create rt extent rounding helpers for realtime extent blocks
  xfs: convert do_div calls to xfs_rtb_to_rtx helper calls
  xfs: create helpers to convert rt block numbers to rt extent numbers
  xfs: create a helper to convert extlen to rtextlen
  xfs: create a helper to compute leftovers of realtime extents
  xfs: create a helper to convert rtextents to rtblocks

fs/xfs/libxfs/xfs_bmap.c

@@ -2989,7 +2989,7 @@ xfs_bmap_extsize_align(
 	 * If realtime, and the result isn't a multiple of the realtime
 	 * extent size we need to remove blocks until it is.
 	 */
-	if (rt && (temp = (align_alen % mp->m_sb.sb_rextsize))) {
+	if (rt && (temp = xfs_extlen_to_rtxmod(mp, align_alen))) {
 		/*
 		 * We're not covering the original request, or
 		 * we won't be able to once we fix the length.
@@ -3016,7 +3016,7 @@ xfs_bmap_extsize_align(
 		else {
 			align_alen -= orig_off - align_off;
 			align_off = orig_off;
-			align_alen -= align_alen % mp->m_sb.sb_rextsize;
+			align_alen -= xfs_extlen_to_rtxmod(mp, align_alen);
 		}
 		/*
 		 * Result doesn't cover the request, fail it.
@@ -4826,12 +4826,8 @@ xfs_bmap_del_extent_delay(
 	ASSERT(got->br_startoff <= del->br_startoff);
 	ASSERT(got_endoff >= del_endoff);
 
-	if (isrt) {
-		uint64_t	rtexts = del->br_blockcount;
-
-		do_div(rtexts, mp->m_sb.sb_rextsize);
-		xfs_mod_frextents(mp, rtexts);
-	}
+	if (isrt)
+		xfs_mod_frextents(mp, xfs_rtb_to_rtx(mp, del->br_blockcount));
 
 	/*
 	 * Update the inode delalloc counter now and wait to update the
@@ -5276,7 +5272,6 @@ __xfs_bunmapi(
 	int			tmp_logflags;	/* partial logging flags */
 	int			wasdel;		/* was a delayed alloc extent */
 	int			whichfork;	/* data or attribute fork */
-	xfs_fsblock_t		sum;
 	xfs_filblks_t		len = *rlen;	/* length to unmap in file */
 	xfs_fileoff_t		end;
 	struct xfs_iext_cursor	icur;
@@ -5371,8 +5366,8 @@ __xfs_bunmapi(
 		if (!isrt)
 			goto delete;
 
-		sum = del.br_startblock + del.br_blockcount;
-		div_u64_rem(sum, mp->m_sb.sb_rextsize, &mod);
+		mod = xfs_rtb_to_rtxoff(mp,
+				del.br_startblock + del.br_blockcount);
 		if (mod) {
 			/*
 			 * Realtime extent not lined up at the end.
@@ -5419,7 +5414,8 @@ __xfs_bunmapi(
 				goto error0;
 			goto nodelete;
 		}
-		div_u64_rem(del.br_startblock, mp->m_sb.sb_rextsize, &mod);
+
+		mod = xfs_rtb_to_rtxoff(mp, del.br_startblock);
 		if (mod) {
 			xfs_extlen_t off = mp->m_sb.sb_rextsize - mod;
 

fs/xfs/libxfs/xfs_rtbitmap.c

@@ -1024,13 +1024,13 @@ xfs_rtfree_blocks(
 
 	ASSERT(rtlen <= XFS_MAX_BMBT_EXTLEN);
 
-	len = div_u64_rem(rtlen, mp->m_sb.sb_rextsize, &mod);
+	len = xfs_rtb_to_rtxrem(mp, rtlen, &mod);
 	if (mod) {
 		ASSERT(mod == 0);
 		return -EIO;
 	}
 
-	start = div_u64_rem(rtbno, mp->m_sb.sb_rextsize, &mod);
+	start = xfs_rtb_to_rtxrem(mp, rtbno, &mod);
 	if (mod) {
 		ASSERT(mod == 0);
 		return -EIO;

fs/xfs/libxfs/xfs_rtbitmap.h

@@ -6,6 +6,131 @@
 #ifndef __XFS_RTBITMAP_H__
 #define	__XFS_RTBITMAP_H__
 
+static inline xfs_rtblock_t
+xfs_rtx_to_rtb(
+	struct xfs_mount	*mp,
+	xfs_rtxnum_t		rtx)
+{
+	if (mp->m_rtxblklog >= 0)
+		return rtx << mp->m_rtxblklog;
+
+	return rtx * mp->m_sb.sb_rextsize;
+}
+
+static inline xfs_extlen_t
+xfs_rtxlen_to_extlen(
+	struct xfs_mount	*mp,
+	xfs_rtxlen_t		rtxlen)
+{
+	if (mp->m_rtxblklog >= 0)
+		return rtxlen << mp->m_rtxblklog;
+
+	return rtxlen * mp->m_sb.sb_rextsize;
+}
+
+/* Compute the misalignment between an extent length and a realtime extent .*/
+static inline unsigned int
+xfs_extlen_to_rtxmod(
+	struct xfs_mount	*mp,
+	xfs_extlen_t		len)
+{
+	if (mp->m_rtxblklog >= 0)
+		return len & mp->m_rtxblkmask;
+
+	return len % mp->m_sb.sb_rextsize;
+}
+
+static inline xfs_rtxlen_t
+xfs_extlen_to_rtxlen(
+	struct xfs_mount	*mp,
+	xfs_extlen_t		len)
+{
+	if (mp->m_rtxblklog >= 0)
+		return len >> mp->m_rtxblklog;
+
+	return len / mp->m_sb.sb_rextsize;
+}
+
+/* Convert an rt block number into an rt extent number. */
+static inline xfs_rtxnum_t
+xfs_rtb_to_rtx(
+	struct xfs_mount	*mp,
+	xfs_rtblock_t		rtbno)
+{
+	if (likely(mp->m_rtxblklog >= 0))
+		return rtbno >> mp->m_rtxblklog;
+
+	return div_u64(rtbno, mp->m_sb.sb_rextsize);
+}
+
+/* Return the offset of an rt block number within an rt extent. */
+static inline xfs_extlen_t
+xfs_rtb_to_rtxoff(
+	struct xfs_mount	*mp,
+	xfs_rtblock_t		rtbno)
+{
+	if (likely(mp->m_rtxblklog >= 0))
+		return rtbno & mp->m_rtxblkmask;
+
+	return do_div(rtbno, mp->m_sb.sb_rextsize);
+}
+
+/*
+ * Crack an rt block number into an rt extent number and an offset within that
+ * rt extent.  Returns the rt extent number directly and the offset in @off.
+ */
+static inline xfs_rtxnum_t
+xfs_rtb_to_rtxrem(
+	struct xfs_mount	*mp,
+	xfs_rtblock_t		rtbno,
+	xfs_extlen_t		*off)
+{
+	if (likely(mp->m_rtxblklog >= 0)) {
+		*off = rtbno & mp->m_rtxblkmask;
+		return rtbno >> mp->m_rtxblklog;
+	}
+
+	return div_u64_rem(rtbno, mp->m_sb.sb_rextsize, off);
+}
+
+/*
+ * Convert an rt block number into an rt extent number, rounding up to the next
+ * rt extent if the rt block is not aligned to an rt extent boundary.
+ */
+static inline xfs_rtxnum_t
+xfs_rtb_to_rtxup(
+	struct xfs_mount	*mp,
+	xfs_rtblock_t		rtbno)
+{
+	if (likely(mp->m_rtxblklog >= 0)) {
+		if (rtbno & mp->m_rtxblkmask)
+			return (rtbno >> mp->m_rtxblklog) + 1;
+		return rtbno >> mp->m_rtxblklog;
+	}
+
+	if (do_div(rtbno, mp->m_sb.sb_rextsize))
+		rtbno++;
+	return rtbno;
+}
+
+/* Round this rtblock up to the nearest rt extent size. */
+static inline xfs_rtblock_t
+xfs_rtb_roundup_rtx(
+	struct xfs_mount	*mp,
+	xfs_rtblock_t		rtbno)
+{
+	return roundup_64(rtbno, mp->m_sb.sb_rextsize);
+}
+
+/* Round this rtblock down to the nearest rt extent size. */
+static inline xfs_rtblock_t
+xfs_rtb_rounddown_rtx(
+	struct xfs_mount	*mp,
+	xfs_rtblock_t		rtbno)
+{
+	return rounddown_64(rtbno, mp->m_sb.sb_rextsize);
+}
+
 /*
  * Functions for walking free space rtextents in the realtime bitmap.
  */

fs/xfs/libxfs/xfs_sb.c

@@ -975,6 +975,8 @@ xfs_sb_mount_common(
 	mp->m_blockmask = sbp->sb_blocksize - 1;
 	mp->m_blockwsize = sbp->sb_blocksize >> XFS_WORDLOG;
 	mp->m_blockwmask = mp->m_blockwsize - 1;
+	mp->m_rtxblklog = log2_if_power2(sbp->sb_rextsize);
+	mp->m_rtxblkmask = mask64_if_power2(sbp->sb_rextsize);
 
 	mp->m_alloc_mxr[0] = xfs_allocbt_maxrecs(mp, sbp->sb_blocksize, 1);
 	mp->m_alloc_mxr[1] = xfs_allocbt_maxrecs(mp, sbp->sb_blocksize, 0);

fs/xfs/libxfs/xfs_trans_resv.c

@@ -19,6 +19,7 @@
 #include "xfs_trans.h"
 #include "xfs_qm.h"
 #include "xfs_trans_space.h"
+#include "xfs_rtbitmap.h"
 
 #define _ALLOC	true
 #define _FREE	false
@@ -220,7 +221,7 @@ xfs_rtalloc_block_count(
 	unsigned int		blksz = XFS_FSB_TO_B(mp, 1);
 	unsigned int		rtbmp_bytes;
 
-	rtbmp_bytes = (XFS_MAX_BMBT_EXTLEN / mp->m_sb.sb_rextsize) / NBBY;
+	rtbmp_bytes = xfs_extlen_to_rtxlen(mp, XFS_MAX_BMBT_EXTLEN) / NBBY;
 	return (howmany(rtbmp_bytes, blksz) + 1) * num_ops;
 }
 

fs/xfs/scrub/inode.c

@@ -20,6 +20,7 @@
 #include "xfs_reflink.h"
 #include "xfs_rmap.h"
 #include "xfs_bmap_util.h"
+#include "xfs_rtbitmap.h"
 #include "scrub/scrub.h"
 #include "scrub/common.h"
 #include "scrub/btree.h"
@@ -225,7 +226,7 @@ xchk_inode_extsize(
 	 */
 	if ((flags & XFS_DIFLAG_RTINHERIT) &&
 	    (flags & XFS_DIFLAG_EXTSZINHERIT) &&
-	    value % sc->mp->m_sb.sb_rextsize > 0)
+	    xfs_extlen_to_rtxmod(sc->mp, value) > 0)
 		xchk_ino_set_warning(sc, ino);
 }
 

fs/xfs/scrub/rtbitmap.c

@@ -50,8 +50,8 @@ xchk_rtbitmap_rec(
 	xfs_rtblock_t		startblock;
 	xfs_filblks_t		blockcount;
 
-	startblock = rec->ar_startext * mp->m_sb.sb_rextsize;
-	blockcount = rec->ar_extcount * mp->m_sb.sb_rextsize;
+	startblock = xfs_rtx_to_rtb(mp, rec->ar_startext);
+	blockcount = xfs_rtx_to_rtb(mp, rec->ar_extcount);
 
 	if (!xfs_verify_rtbext(mp, startblock, blockcount))
 		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
@@ -128,26 +128,22 @@ xchk_rtbitmap(
 void
 xchk_xref_is_used_rt_space(
 	struct xfs_scrub	*sc,
-	xfs_rtblock_t		fsbno,
+	xfs_rtblock_t		rtbno,
 	xfs_extlen_t		len)
 {
 	xfs_rtxnum_t		startext;
 	xfs_rtxnum_t		endext;
-	xfs_rtxlen_t		extcount;
 	bool			is_free;
 	int			error;
 
 	if (xchk_skip_xref(sc->sm))
 		return;
 
-	startext = fsbno;
-	endext = fsbno + len - 1;
-	do_div(startext, sc->mp->m_sb.sb_rextsize);
-	do_div(endext, sc->mp->m_sb.sb_rextsize);
-	extcount = endext - startext + 1;
+	startext = xfs_rtb_to_rtx(sc->mp, rtbno);
+	endext = xfs_rtb_to_rtx(sc->mp, rtbno + len - 1);
 	xfs_ilock(sc->mp->m_rbmip, XFS_ILOCK_SHARED | XFS_ILOCK_RTBITMAP);
-	error = xfs_rtalloc_extent_is_free(sc->mp, sc->tp, startext, extcount,
-			&is_free);
+	error = xfs_rtalloc_extent_is_free(sc->mp, sc->tp, startext,
+			endext - startext + 1, &is_free);
 	if (!xchk_should_check_xref(sc, &error, NULL))
 		goto out_unlock;
 	if (is_free)

fs/xfs/scrub/rtsummary.c

@@ -134,8 +134,8 @@ xchk_rtsum_record_free(
 	lenlog = XFS_RTBLOCKLOG(rec->ar_extcount);
 	offs = XFS_SUMOFFS(mp, lenlog, rbmoff);
 
-	rtbno = rec->ar_startext * mp->m_sb.sb_rextsize;
-	rtlen = rec->ar_extcount * mp->m_sb.sb_rextsize;
+	rtbno = xfs_rtx_to_rtb(mp, rec->ar_startext);
+	rtlen = xfs_rtx_to_rtb(mp, rec->ar_extcount);
 
 	if (!xfs_verify_rtbext(mp, rtbno, rtlen)) {
 		xchk_ino_xref_set_corrupt(sc, mp->m_rbmip->i_ino);

fs/xfs/xfs_bmap_util.c

@@ -28,6 +28,7 @@
 #include "xfs_icache.h"
 #include "xfs_iomap.h"
 #include "xfs_reflink.h"
+#include "xfs_rtbitmap.h"
 
 /* Kernel only BMAP related definitions and functions */
 
@@ -89,14 +90,14 @@ xfs_bmap_rtalloc(
 
 	align = xfs_get_extsz_hint(ap->ip);
 retry:
-	prod = align / mp->m_sb.sb_rextsize;
+	prod = xfs_extlen_to_rtxlen(mp, align);
 	error = xfs_bmap_extsize_align(mp, &ap->got, &ap->prev,
 					align, 1, ap->eof, 0,
 					ap->conv, &ap->offset, &ap->length);
 	if (error)
 		return error;
 	ASSERT(ap->length);
-	ASSERT(ap->length % mp->m_sb.sb_rextsize == 0);
+	ASSERT(xfs_extlen_to_rtxmod(mp, ap->length) == 0);
 
 	/*
 	 * If we shifted the file offset downward to satisfy an extent size
@@ -116,17 +117,14 @@ xfs_bmap_rtalloc(
 		prod = 1;
 	/*
 	 * Set ralen to be the actual requested length in rtextents.
-	 */
-	ralen = ap->length / mp->m_sb.sb_rextsize;
-	/*
+	 *
 	 * If the old value was close enough to XFS_BMBT_MAX_EXTLEN that
 	 * we rounded up to it, cut it back so it's valid again.
 	 * Note that if it's a really large request (bigger than
 	 * XFS_BMBT_MAX_EXTLEN), we don't hear about that number, and can't
 	 * adjust the starting point to match it.
 	 */
-	if (ralen * mp->m_sb.sb_rextsize >= XFS_MAX_BMBT_EXTLEN)
-		ralen = XFS_MAX_BMBT_EXTLEN / mp->m_sb.sb_rextsize;
+	ralen = xfs_extlen_to_rtxlen(mp, min(ap->length, XFS_MAX_BMBT_EXTLEN));
 
 	/*
 	 * Lock out modifications to both the RT bitmap and summary inodes
@@ -147,7 +145,7 @@ xfs_bmap_rtalloc(
 		error = xfs_rtpick_extent(mp, ap->tp, ralen, &rtx);
 		if (error)
 			return error;
-		ap->blkno = rtx * mp->m_sb.sb_rextsize;
+		ap->blkno = xfs_rtx_to_rtb(mp, rtx);
 	} else {
 		ap->blkno = 0;
 	}
@@ -158,20 +156,18 @@ xfs_bmap_rtalloc(
 	 * Realtime allocation, done through xfs_rtallocate_extent.
 	 */
 	if (ignore_locality)
-		ap->blkno = 0;
+		rtx = 0;
 	else
-		do_div(ap->blkno, mp->m_sb.sb_rextsize);
-	rtx = ap->blkno;
-	ap->length = ralen;
-	raminlen = max_t(xfs_extlen_t, 1, minlen / mp->m_sb.sb_rextsize);
-	error = xfs_rtallocate_extent(ap->tp, ap->blkno, raminlen, ap->length,
-			&ralen, ap->wasdel, prod, &rtx);
+		rtx = xfs_rtb_to_rtx(mp, ap->blkno);
+	raminlen = max_t(xfs_rtxlen_t, 1, xfs_extlen_to_rtxlen(mp, minlen));
+	error = xfs_rtallocate_extent(ap->tp, rtx, raminlen, ralen, &ralen,
+			ap->wasdel, prod, &rtx);
 	if (error)
 		return error;
 
 	if (rtx != NULLRTEXTNO) {
-		ap->blkno = rtx * mp->m_sb.sb_rextsize;
-		ap->length = ralen * mp->m_sb.sb_rextsize;
+		ap->blkno = xfs_rtx_to_rtb(mp, rtx);
+		ap->length = xfs_rtxlen_to_extlen(mp, ralen);
 		ap->ip->i_nblocks += ap->length;
 		xfs_trans_log_inode(ap->tp, ap->ip, XFS_ILOG_CORE);
 		if (ap->wasdel)
@@ -688,7 +684,7 @@ xfs_can_free_eofblocks(
 	 */
 	end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_ISIZE(ip));
 	if (XFS_IS_REALTIME_INODE(ip) && mp->m_sb.sb_rextsize > 1)
-		end_fsb = roundup_64(end_fsb, mp->m_sb.sb_rextsize);
+		end_fsb = xfs_rtb_roundup_rtx(mp, end_fsb);
 	last_fsb = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes);
 	if (last_fsb <= end_fsb)
 		return false;
@@ -987,10 +983,8 @@ xfs_free_file_space(
 
 	/* We can only free complete realtime extents. */
 	if (XFS_IS_REALTIME_INODE(ip) && mp->m_sb.sb_rextsize > 1) {
-		startoffset_fsb = roundup_64(startoffset_fsb,
-					     mp->m_sb.sb_rextsize);
-		endoffset_fsb = rounddown_64(endoffset_fsb,
-					     mp->m_sb.sb_rextsize);
+		startoffset_fsb = xfs_rtb_roundup_rtx(mp, startoffset_fsb);
+		endoffset_fsb = xfs_rtb_rounddown_rtx(mp, endoffset_fsb);
 	}
 
 	/*

fs/xfs/xfs_fsmap.c

@@ -483,11 +483,11 @@ xfs_getfsmap_rtdev_rtbitmap_helper(
 	xfs_rtblock_t			rtbno;
 	xfs_daddr_t			rec_daddr, len_daddr;
 
-	rtbno = rec->ar_startext * mp->m_sb.sb_rextsize;
+	rtbno = xfs_rtx_to_rtb(mp, rec->ar_startext);
 	rec_daddr = XFS_FSB_TO_BB(mp, rtbno);
 	irec.rm_startblock = rtbno;
 
-	rtbno = rec->ar_extcount * mp->m_sb.sb_rextsize;
+	rtbno = xfs_rtx_to_rtb(mp, rec->ar_extcount);
 	len_daddr = XFS_FSB_TO_BB(mp, rtbno);
 	irec.rm_blockcount = rtbno;
 
@@ -514,7 +514,7 @@ xfs_getfsmap_rtdev_rtbitmap(
 	uint64_t			eofs;
 	int				error;
 
-	eofs = XFS_FSB_TO_BB(mp, mp->m_sb.sb_rextents * mp->m_sb.sb_rextsize);
+	eofs = XFS_FSB_TO_BB(mp, xfs_rtx_to_rtb(mp, mp->m_sb.sb_rextents));
 	if (keys[0].fmr_physical >= eofs)
 		return 0;
 	start_rtb = XFS_BB_TO_FSBT(mp,
@@ -539,11 +539,8 @@ xfs_getfsmap_rtdev_rtbitmap(
 	 * Set up query parameters to return free rtextents covering the range
 	 * we want.
 	 */
-	alow.ar_startext = start_rtb;
-	ahigh.ar_startext = end_rtb;
-	do_div(alow.ar_startext, mp->m_sb.sb_rextsize);
-	if (do_div(ahigh.ar_startext, mp->m_sb.sb_rextsize))
-		ahigh.ar_startext++;
+	alow.ar_startext = xfs_rtb_to_rtx(mp, start_rtb);
+	ahigh.ar_startext = xfs_rtb_to_rtxup(mp, end_rtb);
 	error = xfs_rtalloc_query_range(mp, tp, &alow, &ahigh,
 			xfs_getfsmap_rtdev_rtbitmap_helper, info);
 	if (error)

fs/xfs/xfs_inode_item.c

@@ -19,6 +19,7 @@
 #include "xfs_log.h"
 #include "xfs_log_priv.h"
 #include "xfs_error.h"
+#include "xfs_rtbitmap.h"
 
 #include <linux/iversion.h>
 
@@ -107,7 +108,7 @@ xfs_inode_item_precommit(
 	 */
 	if ((ip->i_diflags & XFS_DIFLAG_RTINHERIT) &&
 	    (ip->i_diflags & XFS_DIFLAG_EXTSZINHERIT) &&
-	    (ip->i_extsize % ip->i_mount->m_sb.sb_rextsize) > 0) {
+	    xfs_extlen_to_rtxmod(ip->i_mount, ip->i_extsize) > 0) {
 		ip->i_diflags &= ~(XFS_DIFLAG_EXTSIZE |
 				   XFS_DIFLAG_EXTSZINHERIT);
 		ip->i_extsize = 0;

fs/xfs/xfs_ioctl.c

@@ -38,6 +38,7 @@
 #include "xfs_reflink.h"
 #include "xfs_ioctl.h"
 #include "xfs_xattr.h"
+#include "xfs_rtbitmap.h"
 
 #include <linux/mount.h>
 #include <linux/namei.h>
@@ -1004,7 +1005,7 @@ xfs_fill_fsxattr(
 		 * later.
 		 */
 		if ((ip->i_diflags & XFS_DIFLAG_RTINHERIT) &&
-		    ip->i_extsize % mp->m_sb.sb_rextsize > 0) {
+		    xfs_extlen_to_rtxmod(mp, ip->i_extsize) > 0) {
 			fa->fsx_xflags &= ~(FS_XFLAG_EXTSIZE |
 					    FS_XFLAG_EXTSZINHERIT);
 			fa->fsx_extsize = 0;
@@ -1130,7 +1131,7 @@ xfs_ioctl_setattr_xflags(
 	/* If realtime flag is set then must have realtime device */
 	if (fa->fsx_xflags & FS_XFLAG_REALTIME) {
 		if (mp->m_sb.sb_rblocks == 0 || mp->m_sb.sb_rextsize == 0 ||
-		    (ip->i_extsize % mp->m_sb.sb_rextsize))
+		    xfs_extlen_to_rtxmod(mp, ip->i_extsize))
 			return -EINVAL;
 	}
 

fs/xfs/xfs_linux.h

@@ -198,6 +198,18 @@ static inline uint64_t howmany_64(uint64_t x, uint32_t y)
 	return x;
 }
 
+/* If @b is a power of 2, return log2(b).  Else return -1. */
+static inline int8_t log2_if_power2(unsigned long b)
+{
+	return is_power_of_2(b) ? ilog2(b) : -1;
+}
+
+/* If @b is a power of 2, return a mask of the lower bits, else return zero. */
+static inline unsigned long long mask64_if_power2(unsigned long b)
+{
+	return is_power_of_2(b) ? b - 1 : 0;
+}
+
 int xfs_rw_bdev(struct block_device *bdev, sector_t sector, unsigned int count,
 		char *data, enum req_op op);
 

fs/xfs/xfs_mount.h

@@ -119,6 +119,7 @@ typedef struct xfs_mount {
 	uint8_t			m_blkbb_log;	/* blocklog - BBSHIFT */
 	uint8_t			m_agno_log;	/* log #ag's */
 	uint8_t			m_sectbb_log;	/* sectlog - BBSHIFT */
+	int8_t			m_rtxblklog;	/* log2 of rextsize, if possible */
 	uint			m_blockmask;	/* sb_blocksize-1 */
 	uint			m_blockwsize;	/* sb_blocksize in words */
 	uint			m_blockwmask;	/* blockwsize-1 */
@@ -152,6 +153,7 @@ typedef struct xfs_mount {
 	uint64_t		m_features;	/* active filesystem features */
 	uint64_t		m_low_space[XFS_LOWSP_MAX];
 	uint64_t		m_low_rtexts[XFS_LOWSP_MAX];
+	uint64_t		m_rtxblkmask;	/* rt extent block mask */
 	struct xfs_ino_geometry	m_ino_geo;	/* inode geometry */
 	struct xfs_trans_resv	m_resv;		/* precomputed res values */
 						/* low free space thresholds */

fs/xfs/xfs_rtalloc.c

@@ -1054,12 +1054,12 @@ xfs_growfs_rt(
 		 * Calculate new sb and mount fields for this round.
 		 */
 		nsbp->sb_rextsize = in->extsize;
+		nmp->m_rtxblklog = -1; /* don't use shift or masking */
 		nsbp->sb_rbmblocks = bmbno + 1;
 		nrblocks_step = (bmbno + 1) * NBBY * nsbp->sb_blocksize *
 				nsbp->sb_rextsize;
 		nsbp->sb_rblocks = min(nrblocks, nrblocks_step);
-		nsbp->sb_rextents = nsbp->sb_rblocks;
-		do_div(nsbp->sb_rextents, nsbp->sb_rextsize);
+		nsbp->sb_rextents = xfs_rtb_to_rtx(nmp, nsbp->sb_rblocks);
 		ASSERT(nsbp->sb_rextents != 0);
 		nsbp->sb_rextslog = xfs_highbit32(nsbp->sb_rextents);
 		nrsumlevels = nmp->m_rsumlevels = nsbp->sb_rextslog + 1;

fs/xfs/xfs_super.c

@@ -42,6 +42,7 @@
 #include "xfs_xattr.h"
 #include "xfs_iunlink_item.h"
 #include "xfs_dahash_test.h"
+#include "xfs_rtbitmap.h"
 #include "scrub/stats.h"
 
 #include <linux/magic.h>
@@ -890,7 +891,7 @@ xfs_fs_statfs(
 
 		statp->f_blocks = sbp->sb_rblocks;
 		freertx = percpu_counter_sum_positive(&mp->m_frextents);
-		statp->f_bavail = statp->f_bfree = freertx * sbp->sb_rextsize;
+		statp->f_bavail = statp->f_bfree = xfs_rtx_to_rtb(mp, freertx);
 	}
 
 	return 0;

fs/xfs/xfs_trans.c

@@ -24,6 +24,7 @@
 #include "xfs_dquot_item.h"
 #include "xfs_dquot.h"
 #include "xfs_icache.h"
+#include "xfs_rtbitmap.h"
 
 struct kmem_cache	*xfs_trans_cache;
 
@@ -655,6 +656,10 @@ xfs_trans_unreserve_and_mod_sb(
 	mp->m_sb.sb_agcount += tp->t_agcount_delta;
 	mp->m_sb.sb_imax_pct += tp->t_imaxpct_delta;
 	mp->m_sb.sb_rextsize += tp->t_rextsize_delta;
+	if (tp->t_rextsize_delta) {
+		mp->m_rtxblklog = log2_if_power2(mp->m_sb.sb_rextsize);
+		mp->m_rtxblkmask = mask64_if_power2(mp->m_sb.sb_rextsize);
+	}
 	mp->m_sb.sb_rbmblocks += tp->t_rbmblocks_delta;
 	mp->m_sb.sb_rblocks += tp->t_rblocks_delta;
 	mp->m_sb.sb_rextents += tp->t_rextents_delta;
@@ -1196,7 +1201,7 @@ xfs_trans_alloc_inode(
 
 retry:
 	error = xfs_trans_alloc(mp, resv, dblocks,
-			rblocks / mp->m_sb.sb_rextsize,
+			xfs_extlen_to_rtxlen(mp, rblocks),
 			force ? XFS_TRANS_RESERVE : 0, &tp);
 	if (error)
 		return error;