Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1860 insertions, 0 deletions

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
new file mode 100644
index 0000000000..fcefab6872
--- /dev/null
+++ b/fs/xfs/xfs_bmap_util.c
@@ -0,0 +1,1860 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2000-2006 Silicon Graphics, Inc.
+ * Copyright (c) 2012 Red Hat, Inc.
+ * All Rights Reserved.
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_bit.h"
+#include "xfs_mount.h"
+#include "xfs_defer.h"
+#include "xfs_inode.h"
+#include "xfs_btree.h"
+#include "xfs_trans.h"
+#include "xfs_alloc.h"
+#include "xfs_bmap.h"
+#include "xfs_bmap_util.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_rtalloc.h"
+#include "xfs_error.h"
+#include "xfs_quota.h"
+#include "xfs_trans_space.h"
+#include "xfs_trace.h"
+#include "xfs_icache.h"
+#include "xfs_iomap.h"
+#include "xfs_reflink.h"
+
+/* Kernel only BMAP related definitions and functions */
+
+/*
+ * Convert the given file system block to a disk block.  We have to treat it
+ * differently based on whether the file is a real time file or not, because the
+ * bmap code does.
+ */
+xfs_daddr_t
+xfs_fsb_to_db(struct xfs_inode *ip, xfs_fsblock_t fsb)
+{
+	if (XFS_IS_REALTIME_INODE(ip))
+		return XFS_FSB_TO_BB(ip->i_mount, fsb);
+	return XFS_FSB_TO_DADDR(ip->i_mount, fsb);
+}
+
+/*
+ * Routine to zero an extent on disk allocated to the specific inode.
+ *
+ * The VFS functions take a linearised filesystem block offset, so we have to
+ * convert the sparse xfs fsb to the right format first.
+ * VFS types are real funky, too.
+ */
+int
+xfs_zero_extent(
+	struct xfs_inode	*ip,
+	xfs_fsblock_t		start_fsb,
+	xfs_off_t		count_fsb)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_buftarg	*target = xfs_inode_buftarg(ip);
+	xfs_daddr_t		sector = xfs_fsb_to_db(ip, start_fsb);
+	sector_t		block = XFS_BB_TO_FSBT(mp, sector);
+
+	return blkdev_issue_zeroout(target->bt_bdev,
+		block << (mp->m_super->s_blocksize_bits - 9),
+		count_fsb << (mp->m_super->s_blocksize_bits - 9),
+		GFP_NOFS, 0);
+}
+
+#ifdef CONFIG_XFS_RT
+int
+xfs_bmap_rtalloc(
+	struct xfs_bmalloca	*ap)
+{
+	struct xfs_mount	*mp = ap->ip->i_mount;
+	xfs_fileoff_t		orig_offset = ap->offset;
+	xfs_rtblock_t		rtb;
+	xfs_extlen_t		prod = 0;  /* product factor for allocators */
+	xfs_extlen_t		mod = 0;   /* product factor for allocators */
+	xfs_extlen_t		ralen = 0; /* realtime allocation length */
+	xfs_extlen_t		align;     /* minimum allocation alignment */
+	xfs_extlen_t		orig_length = ap->length;
+	xfs_extlen_t		minlen = mp->m_sb.sb_rextsize;
+	xfs_extlen_t		raminlen;
+	bool			rtlocked = false;
+	bool			ignore_locality = false;
+	int			error;
+
+	align = xfs_get_extsz_hint(ap->ip);
+retry:
+	prod = align / mp->m_sb.sb_rextsize;
+	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);
+
+	/*
+	 * If we shifted the file offset downward to satisfy an extent size
+	 * hint, increase minlen by that amount so that the allocator won't
+	 * give us an allocation that's too short to cover at least one of the
+	 * blocks that the caller asked for.
+	 */
+	if (ap->offset != orig_offset)
+		minlen += orig_offset - ap->offset;
+
+	/*
+	 * If the offset & length are not perfectly aligned
+	 * then kill prod, it will just get us in trouble.
+	 */
+	div_u64_rem(ap->offset, align, &mod);
+	if (mod || ap->length % align)
+		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;
+
+	/*
+	 * Lock out modifications to both the RT bitmap and summary inodes
+	 */
+	if (!rtlocked) {
+		xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL|XFS_ILOCK_RTBITMAP);
+		xfs_trans_ijoin(ap->tp, mp->m_rbmip, XFS_ILOCK_EXCL);
+		xfs_ilock(mp->m_rsumip, XFS_ILOCK_EXCL|XFS_ILOCK_RTSUM);
+		xfs_trans_ijoin(ap->tp, mp->m_rsumip, XFS_ILOCK_EXCL);
+		rtlocked = true;
+	}
+
+	/*
+	 * If it's an allocation to an empty file at offset 0,
+	 * pick an extent that will space things out in the rt area.
+	 */
+	if (ap->eof && ap->offset == 0) {
+		xfs_rtblock_t rtx; /* realtime extent no */
+
+		error = xfs_rtpick_extent(mp, ap->tp, ralen, &rtx);
+		if (error)
+			return error;
+		ap->blkno = rtx * mp->m_sb.sb_rextsize;
+	} else {
+		ap->blkno = 0;
+	}
+
+	xfs_bmap_adjacent(ap);
+
+	/*
+	 * Realtime allocation, done through xfs_rtallocate_extent.
+	 */
+	if (ignore_locality)
+		ap->blkno = 0;
+	else
+		do_div(ap->blkno, mp->m_sb.sb_rextsize);
+	rtb = 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, &rtb);
+	if (error)
+		return error;
+
+	if (rtb != NULLRTBLOCK) {
+		ap->blkno = rtb * mp->m_sb.sb_rextsize;
+		ap->length = ralen * mp->m_sb.sb_rextsize;
+		ap->ip->i_nblocks += ap->length;
+		xfs_trans_log_inode(ap->tp, ap->ip, XFS_ILOG_CORE);
+		if (ap->wasdel)
+			ap->ip->i_delayed_blks -= ap->length;
+		/*
+		 * Adjust the disk quota also. This was reserved
+		 * earlier.
+		 */
+		xfs_trans_mod_dquot_byino(ap->tp, ap->ip,
+			ap->wasdel ? XFS_TRANS_DQ_DELRTBCOUNT :
+					XFS_TRANS_DQ_RTBCOUNT, ap->length);
+		return 0;
+	}
+
+	if (align > mp->m_sb.sb_rextsize) {
+		/*
+		 * We previously enlarged the request length to try to satisfy
+		 * an extent size hint.  The allocator didn't return anything,
+		 * so reset the parameters to the original values and try again
+		 * without alignment criteria.
+		 */
+		ap->offset = orig_offset;
+		ap->length = orig_length;
+		minlen = align = mp->m_sb.sb_rextsize;
+		goto retry;
+	}
+
+	if (!ignore_locality && ap->blkno != 0) {
+		/*
+		 * If we can't allocate near a specific rt extent, try again
+		 * without locality criteria.
+		 */
+		ignore_locality = true;
+		goto retry;
+	}
+
+	ap->blkno = NULLFSBLOCK;
+	ap->length = 0;
+	return 0;
+}
+#endif /* CONFIG_XFS_RT */
+
+/*
+ * Extent tree block counting routines.
+ */
+
+/*
+ * Count leaf blocks given a range of extent records.  Delayed allocation
+ * extents are not counted towards the totals.
+ */
+xfs_extnum_t
+xfs_bmap_count_leaves(
+	struct xfs_ifork	*ifp,
+	xfs_filblks_t		*count)
+{
+	struct xfs_iext_cursor	icur;
+	struct xfs_bmbt_irec	got;
+	xfs_extnum_t		numrecs = 0;
+
+	for_each_xfs_iext(ifp, &icur, &got) {
+		if (!isnullstartblock(got.br_startblock)) {
+			*count += got.br_blockcount;
+			numrecs++;
+		}
+	}
+
+	return numrecs;
+}
+
+/*
+ * Count fsblocks of the given fork.  Delayed allocation extents are
+ * not counted towards the totals.
+ */
+int
+xfs_bmap_count_blocks(
+	struct xfs_trans	*tp,
+	struct xfs_inode	*ip,
+	int			whichfork,
+	xfs_extnum_t		*nextents,
+	xfs_filblks_t		*count)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, whichfork);
+	struct xfs_btree_cur	*cur;
+	xfs_extlen_t		btblocks = 0;
+	int			error;
+
+	*nextents = 0;
+	*count = 0;
+
+	if (!ifp)
+		return 0;
+
+	switch (ifp->if_format) {
+	case XFS_DINODE_FMT_BTREE:
+		error = xfs_iread_extents(tp, ip, whichfork);
+		if (error)
+			return error;
+
+		cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
+		error = xfs_btree_count_blocks(cur, &btblocks);
+		xfs_btree_del_cursor(cur, error);
+		if (error)
+			return error;
+
+		/*
+		 * xfs_btree_count_blocks includes the root block contained in
+		 * the inode fork in @btblocks, so subtract one because we're
+		 * only interested in allocated disk blocks.
+		 */
+		*count += btblocks - 1;
+
+		fallthrough;
+	case XFS_DINODE_FMT_EXTENTS:
+		*nextents = xfs_bmap_count_leaves(ifp, count);
+		break;
+	}
+
+	return 0;
+}
+
+static int
+xfs_getbmap_report_one(
+	struct xfs_inode	*ip,
+	struct getbmapx		*bmv,
+	struct kgetbmap		*out,
+	int64_t			bmv_end,
+	struct xfs_bmbt_irec	*got)
+{
+	struct kgetbmap		*p = out + bmv->bmv_entries;
+	bool			shared = false;
+	int			error;
+
+	error = xfs_reflink_trim_around_shared(ip, got, &shared);
+	if (error)
+		return error;
+
+	if (isnullstartblock(got->br_startblock) ||
+	    got->br_startblock == DELAYSTARTBLOCK) {
+		/*
+		 * Take the flush completion as being a point-in-time snapshot
+		 * where there are no delalloc extents, and if any new ones
+		 * have been created racily, just skip them as being 'after'
+		 * the flush and so don't get reported.
+		 */
+		if (!(bmv->bmv_iflags & BMV_IF_DELALLOC))
+			return 0;
+
+		p->bmv_oflags |= BMV_OF_DELALLOC;
+		p->bmv_block = -2;
+	} else {
+		p->bmv_block = xfs_fsb_to_db(ip, got->br_startblock);
+	}
+
+	if (got->br_state == XFS_EXT_UNWRITTEN &&
+	    (bmv->bmv_iflags & BMV_IF_PREALLOC))
+		p->bmv_oflags |= BMV_OF_PREALLOC;
+
+	if (shared)
+		p->bmv_oflags |= BMV_OF_SHARED;
+
+	p->bmv_offset = XFS_FSB_TO_BB(ip->i_mount, got->br_startoff);
+	p->bmv_length = XFS_FSB_TO_BB(ip->i_mount, got->br_blockcount);
+
+	bmv->bmv_offset = p->bmv_offset + p->bmv_length;
+	bmv->bmv_length = max(0LL, bmv_end - bmv->bmv_offset);
+	bmv->bmv_entries++;
+	return 0;
+}
+
+static void
+xfs_getbmap_report_hole(
+	struct xfs_inode	*ip,
+	struct getbmapx		*bmv,
+	struct kgetbmap		*out,
+	int64_t			bmv_end,
+	xfs_fileoff_t		bno,
+	xfs_fileoff_t		end)
+{
+	struct kgetbmap		*p = out + bmv->bmv_entries;
+
+	if (bmv->bmv_iflags & BMV_IF_NO_HOLES)
+		return;
+
+	p->bmv_block = -1;
+	p->bmv_offset = XFS_FSB_TO_BB(ip->i_mount, bno);
+	p->bmv_length = XFS_FSB_TO_BB(ip->i_mount, end - bno);
+
+	bmv->bmv_offset = p->bmv_offset + p->bmv_length;
+	bmv->bmv_length = max(0LL, bmv_end - bmv->bmv_offset);
+	bmv->bmv_entries++;
+}
+
+static inline bool
+xfs_getbmap_full(
+	struct getbmapx		*bmv)
+{
+	return bmv->bmv_length == 0 || bmv->bmv_entries >= bmv->bmv_count - 1;
+}
+
+static bool
+xfs_getbmap_next_rec(
+	struct xfs_bmbt_irec	*rec,
+	xfs_fileoff_t		total_end)
+{
+	xfs_fileoff_t		end = rec->br_startoff + rec->br_blockcount;
+
+	if (end == total_end)
+		return false;
+
+	rec->br_startoff += rec->br_blockcount;
+	if (!isnullstartblock(rec->br_startblock) &&
+	    rec->br_startblock != DELAYSTARTBLOCK)
+		rec->br_startblock += rec->br_blockcount;
+	rec->br_blockcount = total_end - end;
+	return true;
+}
+
+/*
+ * Get inode's extents as described in bmv, and format for output.
+ * Calls formatter to fill the user's buffer until all extents
+ * are mapped, until the passed-in bmv->bmv_count slots have
+ * been filled, or until the formatter short-circuits the loop,
+ * if it is tracking filled-in extents on its own.
+ */
+int						/* error code */
+xfs_getbmap(
+	struct xfs_inode	*ip,
+	struct getbmapx		*bmv,		/* user bmap structure */
+	struct kgetbmap		*out)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	int			iflags = bmv->bmv_iflags;
+	int			whichfork, lock, error = 0;
+	int64_t			bmv_end, max_len;
+	xfs_fileoff_t		bno, first_bno;
+	struct xfs_ifork	*ifp;
+	struct xfs_bmbt_irec	got, rec;
+	xfs_filblks_t		len;
+	struct xfs_iext_cursor	icur;
+
+	if (bmv->bmv_iflags & ~BMV_IF_VALID)
+		return -EINVAL;
+#ifndef DEBUG
+	/* Only allow CoW fork queries if we're debugging. */
+	if (iflags & BMV_IF_COWFORK)
+		return -EINVAL;
+#endif
+	if ((iflags & BMV_IF_ATTRFORK) && (iflags & BMV_IF_COWFORK))
+		return -EINVAL;
+
+	if (bmv->bmv_length < -1)
+		return -EINVAL;
+	bmv->bmv_entries = 0;
+	if (bmv->bmv_length == 0)
+		return 0;
+
+	if (iflags & BMV_IF_ATTRFORK)
+		whichfork = XFS_ATTR_FORK;
+	else if (iflags & BMV_IF_COWFORK)
+		whichfork = XFS_COW_FORK;
+	else
+		whichfork = XFS_DATA_FORK;
+
+	xfs_ilock(ip, XFS_IOLOCK_SHARED);
+	switch (whichfork) {
+	case XFS_ATTR_FORK:
+		lock = xfs_ilock_attr_map_shared(ip);
+		if (!xfs_inode_has_attr_fork(ip))
+			goto out_unlock_ilock;
+
+		max_len = 1LL << 32;
+		break;
+	case XFS_COW_FORK:
+		lock = XFS_ILOCK_SHARED;
+		xfs_ilock(ip, lock);
+
+		/* No CoW fork? Just return */
+		if (!xfs_ifork_ptr(ip, whichfork))
+			goto out_unlock_ilock;
+
+		if (xfs_get_cowextsz_hint(ip))
+			max_len = mp->m_super->s_maxbytes;
+		else
+			max_len = XFS_ISIZE(ip);
+		break;
+	case XFS_DATA_FORK:
+		if (!(iflags & BMV_IF_DELALLOC) &&
+		    (ip->i_delayed_blks || XFS_ISIZE(ip) > ip->i_disk_size)) {
+			error = filemap_write_and_wait(VFS_I(ip)->i_mapping);
+			if (error)
+				goto out_unlock_iolock;
+
+			/*
+			 * Even after flushing the inode, there can still be
+			 * delalloc blocks on the inode beyond EOF due to
+			 * speculative preallocation.  These are not removed
+			 * until the release function is called or the inode
+			 * is inactivated.  Hence we cannot assert here that
+			 * ip->i_delayed_blks == 0.
+			 */
+		}
+
+		if (xfs_get_extsz_hint(ip) ||
+		    (ip->i_diflags &
+		     (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)))
+			max_len = mp->m_super->s_maxbytes;
+		else
+			max_len = XFS_ISIZE(ip);
+
+		lock = xfs_ilock_data_map_shared(ip);
+		break;
+	}
+
+	ifp = xfs_ifork_ptr(ip, whichfork);
+
+	switch (ifp->if_format) {
+	case XFS_DINODE_FMT_EXTENTS:
+	case XFS_DINODE_FMT_BTREE:
+		break;
+	case XFS_DINODE_FMT_LOCAL:
+		/* Local format inode forks report no extents. */
+		goto out_unlock_ilock;
+	default:
+		error = -EINVAL;
+		goto out_unlock_ilock;
+	}
+
+	if (bmv->bmv_length == -1) {
+		max_len = XFS_FSB_TO_BB(mp, XFS_B_TO_FSB(mp, max_len));
+		bmv->bmv_length = max(0LL, max_len - bmv->bmv_offset);
+	}
+
+	bmv_end = bmv->bmv_offset + bmv->bmv_length;
+
+	first_bno = bno = XFS_BB_TO_FSBT(mp, bmv->bmv_offset);
+	len = XFS_BB_TO_FSB(mp, bmv->bmv_length);
+
+	error = xfs_iread_extents(NULL, ip, whichfork);
+	if (error)
+		goto out_unlock_ilock;
+
+	if (!xfs_iext_lookup_extent(ip, ifp, bno, &icur, &got)) {
+		/*
+		 * Report a whole-file hole if the delalloc flag is set to
+		 * stay compatible with the old implementation.
+		 */
+		if (iflags & BMV_IF_DELALLOC)
+			xfs_getbmap_report_hole(ip, bmv, out, bmv_end, bno,
+					XFS_B_TO_FSB(mp, XFS_ISIZE(ip)));
+		goto out_unlock_ilock;
+	}
+
+	while (!xfs_getbmap_full(bmv)) {
+		xfs_trim_extent(&got, first_bno, len);
+
+		/*
+		 * Report an entry for a hole if this extent doesn't directly
+		 * follow the previous one.
+		 */
+		if (got.br_startoff > bno) {
+			xfs_getbmap_report_hole(ip, bmv, out, bmv_end, bno,
+					got.br_startoff);
+			if (xfs_getbmap_full(bmv))
+				break;
+		}
+
+		/*
+		 * In order to report shared extents accurately, we report each
+		 * distinct shared / unshared part of a single bmbt record with
+		 * an individual getbmapx record.
+		 */
+		bno = got.br_startoff + got.br_blockcount;
+		rec = got;
+		do {
+			error = xfs_getbmap_report_one(ip, bmv, out, bmv_end,
+					&rec);
+			if (error || xfs_getbmap_full(bmv))
+				goto out_unlock_ilock;
+		} while (xfs_getbmap_next_rec(&rec, bno));
+
+		if (!xfs_iext_next_extent(ifp, &icur, &got)) {
+			xfs_fileoff_t	end = XFS_B_TO_FSB(mp, XFS_ISIZE(ip));
+
+			if (bmv->bmv_entries > 0)
+				out[bmv->bmv_entries - 1].bmv_oflags |=
+								BMV_OF_LAST;
+
+			if (whichfork != XFS_ATTR_FORK && bno < end &&
+			    !xfs_getbmap_full(bmv)) {
+				xfs_getbmap_report_hole(ip, bmv, out, bmv_end,
+						bno, end);
+			}
+			break;
+		}
+
+		if (bno >= first_bno + len)
+			break;
+	}
+
+out_unlock_ilock:
+	xfs_iunlock(ip, lock);
+out_unlock_iolock:
+	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
+	return error;
+}
+
+/*
+ * Dead simple method of punching delalyed allocation blocks from a range in
+ * the inode.  This will always punch out both the start and end blocks, even
+ * if the ranges only partially overlap them, so it is up to the caller to
+ * ensure that partial blocks are not passed in.
+ */
+int
+xfs_bmap_punch_delalloc_range(
+	struct xfs_inode	*ip,
+	xfs_off_t		start_byte,
+	xfs_off_t		end_byte)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_ifork	*ifp = &ip->i_df;
+	xfs_fileoff_t		start_fsb = XFS_B_TO_FSBT(mp, start_byte);
+	xfs_fileoff_t		end_fsb = XFS_B_TO_FSB(mp, end_byte);
+	struct xfs_bmbt_irec	got, del;
+	struct xfs_iext_cursor	icur;
+	int			error = 0;
+
+	ASSERT(!xfs_need_iread_extents(ifp));
+
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	if (!xfs_iext_lookup_extent_before(ip, ifp, &end_fsb, &icur, &got))
+		goto out_unlock;
+
+	while (got.br_startoff + got.br_blockcount > start_fsb) {
+		del = got;
+		xfs_trim_extent(&del, start_fsb, end_fsb - start_fsb);
+
+		/*
+		 * A delete can push the cursor forward. Step back to the
+		 * previous extent on non-delalloc or extents outside the
+		 * target range.
+		 */
+		if (!del.br_blockcount ||
+		    !isnullstartblock(del.br_startblock)) {
+			if (!xfs_iext_prev_extent(ifp, &icur, &got))
+				break;
+			continue;
+		}
+
+		error = xfs_bmap_del_extent_delay(ip, XFS_DATA_FORK, &icur,
+						  &got, &del);
+		if (error || !xfs_iext_get_extent(ifp, &icur, &got))
+			break;
+	}
+
+out_unlock:
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	return error;
+}
+
+/*
+ * Test whether it is appropriate to check an inode for and free post EOF
+ * blocks. The 'force' parameter determines whether we should also consider
+ * regular files that are marked preallocated or append-only.
+ */
+bool
+xfs_can_free_eofblocks(
+	struct xfs_inode	*ip,
+	bool			force)
+{
+	struct xfs_bmbt_irec	imap;
+	struct xfs_mount	*mp = ip->i_mount;
+	xfs_fileoff_t		end_fsb;
+	xfs_fileoff_t		last_fsb;
+	int			nimaps = 1;
+	int			error;
+
+	/*
+	 * Caller must either hold the exclusive io lock; or be inactivating
+	 * the inode, which guarantees there are no other users of the inode.
+	 */
+	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL) ||
+	       (VFS_I(ip)->i_state & I_FREEING));
+
+	/* prealloc/delalloc exists only on regular files */
+	if (!S_ISREG(VFS_I(ip)->i_mode))
+		return false;
+
+	/*
+	 * Zero sized files with no cached pages and delalloc blocks will not
+	 * have speculative prealloc/delalloc blocks to remove.
+	 */
+	if (VFS_I(ip)->i_size == 0 &&
+	    VFS_I(ip)->i_mapping->nrpages == 0 &&
+	    ip->i_delayed_blks == 0)
+		return false;
+
+	/* If we haven't read in the extent list, then don't do it now. */
+	if (xfs_need_iread_extents(&ip->i_df))
+		return false;
+
+	/*
+	 * Do not free real preallocated or append-only files unless the file
+	 * has delalloc blocks and we are forced to remove them.
+	 */
+	if (ip->i_diflags & (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND))
+		if (!force || ip->i_delayed_blks == 0)
+			return false;
+
+	/*
+	 * Do not try to free post-EOF blocks if EOF is beyond the end of the
+	 * range supported by the page cache, because the truncation will loop
+	 * forever.
+	 */
+	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);
+	last_fsb = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes);
+	if (last_fsb <= end_fsb)
+		return false;
+
+	/*
+	 * Look up the mapping for the first block past EOF.  If we can't find
+	 * it, there's nothing to free.
+	 */
+	xfs_ilock(ip, XFS_ILOCK_SHARED);
+	error = xfs_bmapi_read(ip, end_fsb, last_fsb - end_fsb, &imap, &nimaps,
+			0);
+	xfs_iunlock(ip, XFS_ILOCK_SHARED);
+	if (error || nimaps == 0)
+		return false;
+
+	/*
+	 * If there's a real mapping there or there are delayed allocation
+	 * reservations, then we have post-EOF blocks to try to free.
+	 */
+	return imap.br_startblock != HOLESTARTBLOCK || ip->i_delayed_blks;
+}
+
+/*
+ * This is called to free any blocks beyond eof. The caller must hold
+ * IOLOCK_EXCL unless we are in the inode reclaim path and have the only
+ * reference to the inode.
+ */
+int
+xfs_free_eofblocks(
+	struct xfs_inode	*ip)
+{
+	struct xfs_trans	*tp;
+	struct xfs_mount	*mp = ip->i_mount;
+	int			error;
+
+	/* Attach the dquots to the inode up front. */
+	error = xfs_qm_dqattach(ip);
+	if (error)
+		return error;
+
+	/* Wait on dio to ensure i_size has settled. */
+	inode_dio_wait(VFS_I(ip));
+
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
+	if (error) {
+		ASSERT(xfs_is_shutdown(mp));
+		return error;
+	}
+
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	xfs_trans_ijoin(tp, ip, 0);
+
+	/*
+	 * Do not update the on-disk file size.  If we update the on-disk file
+	 * size and then the system crashes before the contents of the file are
+	 * flushed to disk then the files may be full of holes (ie NULL files
+	 * bug).
+	 */
+	error = xfs_itruncate_extents_flags(&tp, ip, XFS_DATA_FORK,
+				XFS_ISIZE(ip), XFS_BMAPI_NODISCARD);
+	if (error)
+		goto err_cancel;
+
+	error = xfs_trans_commit(tp);
+	if (error)
+		goto out_unlock;
+
+	xfs_inode_clear_eofblocks_tag(ip);
+	goto out_unlock;
+
+err_cancel:
+	/*
+	 * If we get an error at this point we simply don't
+	 * bother truncating the file.
+	 */
+	xfs_trans_cancel(tp);
+out_unlock:
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	return error;
+}
+
+int
+xfs_alloc_file_space(
+	struct xfs_inode	*ip,
+	xfs_off_t		offset,
+	xfs_off_t		len)
+{
+	xfs_mount_t		*mp = ip->i_mount;
+	xfs_off_t		count;
+	xfs_filblks_t		allocated_fsb;
+	xfs_filblks_t		allocatesize_fsb;
+	xfs_extlen_t		extsz, temp;
+	xfs_fileoff_t		startoffset_fsb;
+	xfs_fileoff_t		endoffset_fsb;
+	int			nimaps;
+	int			rt;
+	xfs_trans_t		*tp;
+	xfs_bmbt_irec_t		imaps[1], *imapp;
+	int			error;
+
+	trace_xfs_alloc_file_space(ip);
+
+	if (xfs_is_shutdown(mp))
+		return -EIO;
+
+	error = xfs_qm_dqattach(ip);
+	if (error)
+		return error;
+
+	if (len <= 0)
+		return -EINVAL;
+
+	rt = XFS_IS_REALTIME_INODE(ip);
+	extsz = xfs_get_extsz_hint(ip);
+
+	count = len;
+	imapp = &imaps[0];
+	nimaps = 1;
+	startoffset_fsb	= XFS_B_TO_FSBT(mp, offset);
+	endoffset_fsb = XFS_B_TO_FSB(mp, offset + count);
+	allocatesize_fsb = endoffset_fsb - startoffset_fsb;
+
+	/*
+	 * Allocate file space until done or until there is an error
+	 */
+	while (allocatesize_fsb && !error) {
+		xfs_fileoff_t	s, e;
+		unsigned int	dblocks, rblocks, resblks;
+
+		/*
+		 * Determine space reservations for data/realtime.
+		 */
+		if (unlikely(extsz)) {
+			s = startoffset_fsb;
+			do_div(s, extsz);
+			s *= extsz;
+			e = startoffset_fsb + allocatesize_fsb;
+			div_u64_rem(startoffset_fsb, extsz, &temp);
+			if (temp)
+				e += temp;
+			div_u64_rem(e, extsz, &temp);
+			if (temp)
+				e += extsz - temp;
+		} else {
+			s = 0;
+			e = allocatesize_fsb;
+		}
+
+		/*
+		 * The transaction reservation is limited to a 32-bit block
+		 * count, hence we need to limit the number of blocks we are
+		 * trying to reserve to avoid an overflow. We can't allocate
+		 * more than @nimaps extents, and an extent is limited on disk
+		 * to XFS_BMBT_MAX_EXTLEN (21 bits), so use that to enforce the
+		 * limit.
+		 */
+		resblks = min_t(xfs_fileoff_t, (e - s),
+				(XFS_MAX_BMBT_EXTLEN * nimaps));
+		if (unlikely(rt)) {
+			dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
+			rblocks = resblks;
+		} else {
+			dblocks = XFS_DIOSTRAT_SPACE_RES(mp, resblks);
+			rblocks = 0;
+		}
+
+		error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write,
+				dblocks, rblocks, false, &tp);
+		if (error)
+			break;
+
+		error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
+				XFS_IEXT_ADD_NOSPLIT_CNT);
+		if (error == -EFBIG)
+			error = xfs_iext_count_upgrade(tp, ip,
+					XFS_IEXT_ADD_NOSPLIT_CNT);
+		if (error)
+			goto error;
+
+		error = xfs_bmapi_write(tp, ip, startoffset_fsb,
+				allocatesize_fsb, XFS_BMAPI_PREALLOC, 0, imapp,
+				&nimaps);
+		if (error)
+			goto error;
+
+		ip->i_diflags |= XFS_DIFLAG_PREALLOC;
+		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+		error = xfs_trans_commit(tp);
+		xfs_iunlock(ip, XFS_ILOCK_EXCL);
+		if (error)
+			break;
+
+		allocated_fsb = imapp->br_blockcount;
+
+		if (nimaps == 0) {
+			error = -ENOSPC;
+			break;
+		}
+
+		startoffset_fsb += allocated_fsb;
+		allocatesize_fsb -= allocated_fsb;
+	}
+
+	return error;
+
+error:
+	xfs_trans_cancel(tp);
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	return error;
+}
+
+static int
+xfs_unmap_extent(
+	struct xfs_inode	*ip,
+	xfs_fileoff_t		startoffset_fsb,
+	xfs_filblks_t		len_fsb,
+	int			*done)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_trans	*tp;
+	uint			resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
+	int			error;
+
+	error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks, 0,
+			false, &tp);
+	if (error)
+		return error;
+
+	error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
+			XFS_IEXT_PUNCH_HOLE_CNT);
+	if (error == -EFBIG)
+		error = xfs_iext_count_upgrade(tp, ip, XFS_IEXT_PUNCH_HOLE_CNT);
+	if (error)
+		goto out_trans_cancel;
+
+	error = xfs_bunmapi(tp, ip, startoffset_fsb, len_fsb, 0, 2, done);
+	if (error)
+		goto out_trans_cancel;
+
+	error = xfs_trans_commit(tp);
+out_unlock:
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	return error;
+
+out_trans_cancel:
+	xfs_trans_cancel(tp);
+	goto out_unlock;
+}
+
+/* Caller must first wait for the completion of any pending DIOs if required. */
+int
+xfs_flush_unmap_range(
+	struct xfs_inode	*ip,
+	xfs_off_t		offset,
+	xfs_off_t		len)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct inode		*inode = VFS_I(ip);
+	xfs_off_t		rounding, start, end;
+	int			error;
+
+	rounding = max_t(xfs_off_t, mp->m_sb.sb_blocksize, PAGE_SIZE);
+	start = round_down(offset, rounding);
+	end = round_up(offset + len, rounding) - 1;
+
+	error = filemap_write_and_wait_range(inode->i_mapping, start, end);
+	if (error)
+		return error;
+	truncate_pagecache_range(inode, start, end);
+	return 0;
+}
+
+int
+xfs_free_file_space(
+	struct xfs_inode	*ip,
+	xfs_off_t		offset,
+	xfs_off_t		len)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	xfs_fileoff_t		startoffset_fsb;
+	xfs_fileoff_t		endoffset_fsb;
+	int			done = 0, error;
+
+	trace_xfs_free_file_space(ip);
+
+	error = xfs_qm_dqattach(ip);
+	if (error)
+		return error;
+
+	if (len <= 0)	/* if nothing being freed */
+		return 0;
+
+	startoffset_fsb = XFS_B_TO_FSB(mp, offset);
+	endoffset_fsb = XFS_B_TO_FSBT(mp, offset + len);
+
+	/* 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);
+	}
+
+	/*
+	 * Need to zero the stuff we're not freeing, on disk.
+	 */
+	if (endoffset_fsb > startoffset_fsb) {
+		while (!done) {
+			error = xfs_unmap_extent(ip, startoffset_fsb,
+					endoffset_fsb - startoffset_fsb, &done);
+			if (error)
+				return error;
+		}
+	}
+
+	/*
+	 * Now that we've unmap all full blocks we'll have to zero out any
+	 * partial block at the beginning and/or end.  xfs_zero_range is smart
+	 * enough to skip any holes, including those we just created, but we
+	 * must take care not to zero beyond EOF and enlarge i_size.
+	 */
+	if (offset >= XFS_ISIZE(ip))
+		return 0;
+	if (offset + len > XFS_ISIZE(ip))
+		len = XFS_ISIZE(ip) - offset;
+	error = xfs_zero_range(ip, offset, len, NULL);
+	if (error)
+		return error;
+
+	/*
+	 * If we zeroed right up to EOF and EOF straddles a page boundary we
+	 * must make sure that the post-EOF area is also zeroed because the
+	 * page could be mmap'd and xfs_zero_range doesn't do that for us.
+	 * Writeback of the eof page will do this, albeit clumsily.
+	 */
+	if (offset + len >= XFS_ISIZE(ip) && offset_in_page(offset + len) > 0) {
+		error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
+				round_down(offset + len, PAGE_SIZE), LLONG_MAX);
+	}
+
+	return error;
+}
+
+static int
+xfs_prepare_shift(
+	struct xfs_inode	*ip,
+	loff_t			offset)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	int			error;
+
+	/*
+	 * Trim eofblocks to avoid shifting uninitialized post-eof preallocation
+	 * into the accessible region of the file.
+	 */
+	if (xfs_can_free_eofblocks(ip, true)) {
+		error = xfs_free_eofblocks(ip);
+		if (error)
+			return error;
+	}
+
+	/*
+	 * Shift operations must stabilize the start block offset boundary along
+	 * with the full range of the operation. If we don't, a COW writeback
+	 * completion could race with an insert, front merge with the start
+	 * extent (after split) during the shift and corrupt the file. Start
+	 * with the block just prior to the start to stabilize the boundary.
+	 */
+	offset = round_down(offset, mp->m_sb.sb_blocksize);
+	if (offset)
+		offset -= mp->m_sb.sb_blocksize;
+
+	/*
+	 * Writeback and invalidate cache for the remainder of the file as we're
+	 * about to shift down every extent from offset to EOF.
+	 */
+	error = xfs_flush_unmap_range(ip, offset, XFS_ISIZE(ip));
+	if (error)
+		return error;
+
+	/*
+	 * Clean out anything hanging around in the cow fork now that
+	 * we've flushed all the dirty data out to disk to avoid having
+	 * CoW extents at the wrong offsets.
+	 */
+	if (xfs_inode_has_cow_data(ip)) {
+		error = xfs_reflink_cancel_cow_range(ip, offset, NULLFILEOFF,
+				true);
+		if (error)
+			return error;
+	}
+
+	return 0;
+}
+
+/*
+ * xfs_collapse_file_space()
+ *	This routine frees disk space and shift extent for the given file.
+ *	The first thing we do is to free data blocks in the specified range
+ *	by calling xfs_free_file_space(). It would also sync dirty data
+ *	and invalidate page cache over the region on which collapse range
+ *	is working. And Shift extent records to the left to cover a hole.
+ * RETURNS:
+ *	0 on success
+ *	errno on error
+ *
+ */
+int
+xfs_collapse_file_space(
+	struct xfs_inode	*ip,
+	xfs_off_t		offset,
+	xfs_off_t		len)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_trans	*tp;
+	int			error;
+	xfs_fileoff_t		next_fsb = XFS_B_TO_FSB(mp, offset + len);
+	xfs_fileoff_t		shift_fsb = XFS_B_TO_FSB(mp, len);
+	bool			done = false;
+
+	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
+	ASSERT(xfs_isilocked(ip, XFS_MMAPLOCK_EXCL));
+
+	trace_xfs_collapse_file_space(ip);
+
+	error = xfs_free_file_space(ip, offset, len);
+	if (error)
+		return error;
+
+	error = xfs_prepare_shift(ip, offset);
+	if (error)
+		return error;
+
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp);
+	if (error)
+		return error;
+
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	xfs_trans_ijoin(tp, ip, 0);
+
+	while (!done) {
+		error = xfs_bmap_collapse_extents(tp, ip, &next_fsb, shift_fsb,
+				&done);
+		if (error)
+			goto out_trans_cancel;
+		if (done)
+			break;
+
+		/* finish any deferred frees and roll the transaction */
+		error = xfs_defer_finish(&tp);
+		if (error)
+			goto out_trans_cancel;
+	}
+
+	error = xfs_trans_commit(tp);
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	return error;
+
+out_trans_cancel:
+	xfs_trans_cancel(tp);
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	return error;
+}
+
+/*
+ * xfs_insert_file_space()
+ *	This routine create hole space by shifting extents for the given file.
+ *	The first thing we do is to sync dirty data and invalidate page cache
+ *	over the region on which insert range is working. And split an extent
+ *	to two extents at given offset by calling xfs_bmap_split_extent.
+ *	And shift all extent records which are laying between [offset,
+ *	last allocated extent] to the right to reserve hole range.
+ * RETURNS:
+ *	0 on success
+ *	errno on error
+ */
+int
+xfs_insert_file_space(
+	struct xfs_inode	*ip,
+	loff_t			offset,
+	loff_t			len)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_trans	*tp;
+	int			error;
+	xfs_fileoff_t		stop_fsb = XFS_B_TO_FSB(mp, offset);
+	xfs_fileoff_t		next_fsb = NULLFSBLOCK;
+	xfs_fileoff_t		shift_fsb = XFS_B_TO_FSB(mp, len);
+	bool			done = false;
+
+	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
+	ASSERT(xfs_isilocked(ip, XFS_MMAPLOCK_EXCL));
+
+	trace_xfs_insert_file_space(ip);
+
+	error = xfs_bmap_can_insert_extents(ip, stop_fsb, shift_fsb);
+	if (error)
+		return error;
+
+	error = xfs_prepare_shift(ip, offset);
+	if (error)
+		return error;
+
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write,
+			XFS_DIOSTRAT_SPACE_RES(mp, 0), 0, 0, &tp);
+	if (error)
+		return error;
+
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	xfs_trans_ijoin(tp, ip, 0);
+
+	error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
+			XFS_IEXT_PUNCH_HOLE_CNT);
+	if (error == -EFBIG)
+		error = xfs_iext_count_upgrade(tp, ip, XFS_IEXT_PUNCH_HOLE_CNT);
+	if (error)
+		goto out_trans_cancel;
+
+	/*
+	 * The extent shifting code works on extent granularity. So, if stop_fsb
+	 * is not the starting block of extent, we need to split the extent at
+	 * stop_fsb.
+	 */
+	error = xfs_bmap_split_extent(tp, ip, stop_fsb);
+	if (error)
+		goto out_trans_cancel;
+
+	do {
+		error = xfs_defer_finish(&tp);
+		if (error)
+			goto out_trans_cancel;
+
+		error = xfs_bmap_insert_extents(tp, ip, &next_fsb, shift_fsb,
+				&done, stop_fsb);
+		if (error)
+			goto out_trans_cancel;
+	} while (!done);
+
+	error = xfs_trans_commit(tp);
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	return error;
+
+out_trans_cancel:
+	xfs_trans_cancel(tp);
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	return error;
+}
+
+/*
+ * We need to check that the format of the data fork in the temporary inode is
+ * valid for the target inode before doing the swap. This is not a problem with
+ * attr1 because of the fixed fork offset, but attr2 has a dynamically sized
+ * data fork depending on the space the attribute fork is taking so we can get
+ * invalid formats on the target inode.
+ *
+ * E.g. target has space for 7 extents in extent format, temp inode only has
+ * space for 6.  If we defragment down to 7 extents, then the tmp format is a
+ * btree, but when swapped it needs to be in extent format. Hence we can't just
+ * blindly swap data forks on attr2 filesystems.
+ *
+ * Note that we check the swap in both directions so that we don't end up with
+ * a corrupt temporary inode, either.
+ *
+ * Note that fixing the way xfs_fsr sets up the attribute fork in the source
+ * inode will prevent this situation from occurring, so all we do here is
+ * reject and log the attempt. basically we are putting the responsibility on
+ * userspace to get this right.
+ */
+static int
+xfs_swap_extents_check_format(
+	struct xfs_inode	*ip,	/* target inode */
+	struct xfs_inode	*tip)	/* tmp inode */
+{
+	struct xfs_ifork	*ifp = &ip->i_df;
+	struct xfs_ifork	*tifp = &tip->i_df;
+
+	/* User/group/project quota ids must match if quotas are enforced. */
+	if (XFS_IS_QUOTA_ON(ip->i_mount) &&
+	    (!uid_eq(VFS_I(ip)->i_uid, VFS_I(tip)->i_uid) ||
+	     !gid_eq(VFS_I(ip)->i_gid, VFS_I(tip)->i_gid) ||
+	     ip->i_projid != tip->i_projid))
+		return -EINVAL;
+
+	/* Should never get a local format */
+	if (ifp->if_format == XFS_DINODE_FMT_LOCAL ||
+	    tifp->if_format == XFS_DINODE_FMT_LOCAL)
+		return -EINVAL;
+
+	/*
+	 * if the target inode has less extents that then temporary inode then
+	 * why did userspace call us?
+	 */
+	if (ifp->if_nextents < tifp->if_nextents)
+		return -EINVAL;
+
+	/*
+	 * If we have to use the (expensive) rmap swap method, we can
+	 * handle any number of extents and any format.
+	 */
+	if (xfs_has_rmapbt(ip->i_mount))
+		return 0;
+
+	/*
+	 * if the target inode is in extent form and the temp inode is in btree
+	 * form then we will end up with the target inode in the wrong format
+	 * as we already know there are less extents in the temp inode.
+	 */
+	if (ifp->if_format == XFS_DINODE_FMT_EXTENTS &&
+	    tifp->if_format == XFS_DINODE_FMT_BTREE)
+		return -EINVAL;
+
+	/* Check temp in extent form to max in target */
+	if (tifp->if_format == XFS_DINODE_FMT_EXTENTS &&
+	    tifp->if_nextents > XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
+		return -EINVAL;
+
+	/* Check target in extent form to max in temp */
+	if (ifp->if_format == XFS_DINODE_FMT_EXTENTS &&
+	    ifp->if_nextents > XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
+		return -EINVAL;
+
+	/*
+	 * If we are in a btree format, check that the temp root block will fit
+	 * in the target and that it has enough extents to be in btree format
+	 * in the target.
+	 *
+	 * Note that we have to be careful to allow btree->extent conversions
+	 * (a common defrag case) which will occur when the temp inode is in
+	 * extent format...
+	 */
+	if (tifp->if_format == XFS_DINODE_FMT_BTREE) {
+		if (xfs_inode_has_attr_fork(ip) &&
+		    XFS_BMAP_BMDR_SPACE(tifp->if_broot) > xfs_inode_fork_boff(ip))
+			return -EINVAL;
+		if (tifp->if_nextents <= XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
+			return -EINVAL;
+	}
+
+	/* Reciprocal target->temp btree format checks */
+	if (ifp->if_format == XFS_DINODE_FMT_BTREE) {
+		if (xfs_inode_has_attr_fork(tip) &&
+		    XFS_BMAP_BMDR_SPACE(ip->i_df.if_broot) > xfs_inode_fork_boff(tip))
+			return -EINVAL;
+		if (ifp->if_nextents <= XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int
+xfs_swap_extent_flush(
+	struct xfs_inode	*ip)
+{
+	int	error;
+
+	error = filemap_write_and_wait(VFS_I(ip)->i_mapping);
+	if (error)
+		return error;
+	truncate_pagecache_range(VFS_I(ip), 0, -1);
+
+	/* Verify O_DIRECT for ftmp */
+	if (VFS_I(ip)->i_mapping->nrpages)
+		return -EINVAL;
+	return 0;
+}
+
+/*
+ * Move extents from one file to another, when rmap is enabled.
+ */
+STATIC int
+xfs_swap_extent_rmap(
+	struct xfs_trans		**tpp,
+	struct xfs_inode		*ip,
+	struct xfs_inode		*tip)
+{
+	struct xfs_trans		*tp = *tpp;
+	struct xfs_bmbt_irec		irec;
+	struct xfs_bmbt_irec		uirec;
+	struct xfs_bmbt_irec		tirec;
+	xfs_fileoff_t			offset_fsb;
+	xfs_fileoff_t			end_fsb;
+	xfs_filblks_t			count_fsb;
+	int				error;
+	xfs_filblks_t			ilen;
+	xfs_filblks_t			rlen;
+	int				nimaps;
+	uint64_t			tip_flags2;
+
+	/*
+	 * If the source file has shared blocks, we must flag the donor
+	 * file as having shared blocks so that we get the shared-block
+	 * rmap functions when we go to fix up the rmaps.  The flags
+	 * will be switch for reals later.
+	 */
+	tip_flags2 = tip->i_diflags2;
+	if (ip->i_diflags2 & XFS_DIFLAG2_REFLINK)
+		tip->i_diflags2 |= XFS_DIFLAG2_REFLINK;
+
+	offset_fsb = 0;
+	end_fsb = XFS_B_TO_FSB(ip->i_mount, i_size_read(VFS_I(ip)));
+	count_fsb = (xfs_filblks_t)(end_fsb - offset_fsb);
+
+	while (count_fsb) {
+		/* Read extent from the donor file */
+		nimaps = 1;
+		error = xfs_bmapi_read(tip, offset_fsb, count_fsb, &tirec,
+				&nimaps, 0);
+		if (error)
+			goto out;
+		ASSERT(nimaps == 1);
+		ASSERT(tirec.br_startblock != DELAYSTARTBLOCK);
+
+		trace_xfs_swap_extent_rmap_remap(tip, &tirec);
+		ilen = tirec.br_blockcount;
+
+		/* Unmap the old blocks in the source file. */
+		while (tirec.br_blockcount) {
+			ASSERT(tp->t_highest_agno == NULLAGNUMBER);
+			trace_xfs_swap_extent_rmap_remap_piece(tip, &tirec);
+
+			/* Read extent from the source file */
+			nimaps = 1;
+			error = xfs_bmapi_read(ip, tirec.br_startoff,
+					tirec.br_blockcount, &irec,
+					&nimaps, 0);
+			if (error)
+				goto out;
+			ASSERT(nimaps == 1);
+			ASSERT(tirec.br_startoff == irec.br_startoff);
+			trace_xfs_swap_extent_rmap_remap_piece(ip, &irec);
+
+			/* Trim the extent. */
+			uirec = tirec;
+			uirec.br_blockcount = rlen = min_t(xfs_filblks_t,
+					tirec.br_blockcount,
+					irec.br_blockcount);
+			trace_xfs_swap_extent_rmap_remap_piece(tip, &uirec);
+
+			if (xfs_bmap_is_real_extent(&uirec)) {
+				error = xfs_iext_count_may_overflow(ip,
+						XFS_DATA_FORK,
+						XFS_IEXT_SWAP_RMAP_CNT);
+				if (error == -EFBIG)
+					error = xfs_iext_count_upgrade(tp, ip,
+							XFS_IEXT_SWAP_RMAP_CNT);
+				if (error)
+					goto out;
+			}
+
+			if (xfs_bmap_is_real_extent(&irec)) {
+				error = xfs_iext_count_may_overflow(tip,
+						XFS_DATA_FORK,
+						XFS_IEXT_SWAP_RMAP_CNT);
+				if (error == -EFBIG)
+					error = xfs_iext_count_upgrade(tp, ip,
+							XFS_IEXT_SWAP_RMAP_CNT);
+				if (error)
+					goto out;
+			}
+
+			/* Remove the mapping from the donor file. */
+			xfs_bmap_unmap_extent(tp, tip, &uirec);
+
+			/* Remove the mapping from the source file. */
+			xfs_bmap_unmap_extent(tp, ip, &irec);
+
+			/* Map the donor file's blocks into the source file. */
+			xfs_bmap_map_extent(tp, ip, &uirec);
+
+			/* Map the source file's blocks into the donor file. */
+			xfs_bmap_map_extent(tp, tip, &irec);
+
+			error = xfs_defer_finish(tpp);
+			tp = *tpp;
+			if (error)
+				goto out;
+
+			tirec.br_startoff += rlen;
+			if (tirec.br_startblock != HOLESTARTBLOCK &&
+			    tirec.br_startblock != DELAYSTARTBLOCK)
+				tirec.br_startblock += rlen;
+			tirec.br_blockcount -= rlen;
+		}
+
+		/* Roll on... */
+		count_fsb -= ilen;
+		offset_fsb += ilen;
+	}
+
+	tip->i_diflags2 = tip_flags2;
+	return 0;
+
+out:
+	trace_xfs_swap_extent_rmap_error(ip, error, _RET_IP_);
+	tip->i_diflags2 = tip_flags2;
+	return error;
+}
+
+/* Swap the extents of two files by swapping data forks. */
+STATIC int
+xfs_swap_extent_forks(
+	struct xfs_trans	*tp,
+	struct xfs_inode	*ip,
+	struct xfs_inode	*tip,
+	int			*src_log_flags,
+	int			*target_log_flags)
+{
+	xfs_filblks_t		aforkblks = 0;
+	xfs_filblks_t		taforkblks = 0;
+	xfs_extnum_t		junk;
+	uint64_t		tmp;
+	int			error;
+
+	/*
+	 * Count the number of extended attribute blocks
+	 */
+	if (xfs_inode_has_attr_fork(ip) && ip->i_af.if_nextents > 0 &&
+	    ip->i_af.if_format != XFS_DINODE_FMT_LOCAL) {
+		error = xfs_bmap_count_blocks(tp, ip, XFS_ATTR_FORK, &junk,
+				&aforkblks);
+		if (error)
+			return error;
+	}
+	if (xfs_inode_has_attr_fork(tip) && tip->i_af.if_nextents > 0 &&
+	    tip->i_af.if_format != XFS_DINODE_FMT_LOCAL) {
+		error = xfs_bmap_count_blocks(tp, tip, XFS_ATTR_FORK, &junk,
+				&taforkblks);
+		if (error)
+			return error;
+	}
+
+	/*
+	 * Btree format (v3) inodes have the inode number stamped in the bmbt
+	 * block headers. We can't start changing the bmbt blocks until the
+	 * inode owner change is logged so recovery does the right thing in the
+	 * event of a crash. Set the owner change log flags now and leave the
+	 * bmbt scan as the last step.
+	 */
+	if (xfs_has_v3inodes(ip->i_mount)) {
+		if (ip->i_df.if_format == XFS_DINODE_FMT_BTREE)
+			(*target_log_flags) |= XFS_ILOG_DOWNER;
+		if (tip->i_df.if_format == XFS_DINODE_FMT_BTREE)
+			(*src_log_flags) |= XFS_ILOG_DOWNER;
+	}
+
+	/*
+	 * Swap the data forks of the inodes
+	 */
+	swap(ip->i_df, tip->i_df);
+
+	/*
+	 * Fix the on-disk inode values
+	 */
+	tmp = (uint64_t)ip->i_nblocks;
+	ip->i_nblocks = tip->i_nblocks - taforkblks + aforkblks;
+	tip->i_nblocks = tmp + taforkblks - aforkblks;
+
+	/*
+	 * The extents in the source inode could still contain speculative
+	 * preallocation beyond EOF (e.g. the file is open but not modified
+	 * while defrag is in progress). In that case, we need to copy over the
+	 * number of delalloc blocks the data fork in the source inode is
+	 * tracking beyond EOF so that when the fork is truncated away when the
+	 * temporary inode is unlinked we don't underrun the i_delayed_blks
+	 * counter on that inode.
+	 */
+	ASSERT(tip->i_delayed_blks == 0);
+	tip->i_delayed_blks = ip->i_delayed_blks;
+	ip->i_delayed_blks = 0;
+
+	switch (ip->i_df.if_format) {
+	case XFS_DINODE_FMT_EXTENTS:
+		(*src_log_flags) |= XFS_ILOG_DEXT;
+		break;
+	case XFS_DINODE_FMT_BTREE:
+		ASSERT(!xfs_has_v3inodes(ip->i_mount) ||
+		       (*src_log_flags & XFS_ILOG_DOWNER));
+		(*src_log_flags) |= XFS_ILOG_DBROOT;
+		break;
+	}
+
+	switch (tip->i_df.if_format) {
+	case XFS_DINODE_FMT_EXTENTS:
+		(*target_log_flags) |= XFS_ILOG_DEXT;
+		break;
+	case XFS_DINODE_FMT_BTREE:
+		(*target_log_flags) |= XFS_ILOG_DBROOT;
+		ASSERT(!xfs_has_v3inodes(ip->i_mount) ||
+		       (*target_log_flags & XFS_ILOG_DOWNER));
+		break;
+	}
+
+	return 0;
+}
+
+/*
+ * Fix up the owners of the bmbt blocks to refer to the current inode. The
+ * change owner scan attempts to order all modified buffers in the current
+ * transaction. In the event of ordered buffer failure, the offending buffer is
+ * physically logged as a fallback and the scan returns -EAGAIN. We must roll
+ * the transaction in this case to replenish the fallback log reservation and
+ * restart the scan. This process repeats until the scan completes.
+ */
+static int
+xfs_swap_change_owner(
+	struct xfs_trans	**tpp,
+	struct xfs_inode	*ip,
+	struct xfs_inode	*tmpip)
+{
+	int			error;
+	struct xfs_trans	*tp = *tpp;
+
+	do {
+		error = xfs_bmbt_change_owner(tp, ip, XFS_DATA_FORK, ip->i_ino,
+					      NULL);
+		/* success or fatal error */
+		if (error != -EAGAIN)
+			break;
+
+		error = xfs_trans_roll(tpp);
+		if (error)
+			break;
+		tp = *tpp;
+
+		/*
+		 * Redirty both inodes so they can relog and keep the log tail
+		 * moving forward.
+		 */
+		xfs_trans_ijoin(tp, ip, 0);
+		xfs_trans_ijoin(tp, tmpip, 0);
+		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+		xfs_trans_log_inode(tp, tmpip, XFS_ILOG_CORE);
+	} while (true);
+
+	return error;
+}
+
+int
+xfs_swap_extents(
+	struct xfs_inode	*ip,	/* target inode */
+	struct xfs_inode	*tip,	/* tmp inode */
+	struct xfs_swapext	*sxp)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_trans	*tp;
+	struct xfs_bstat	*sbp = &sxp->sx_stat;
+	int			src_log_flags, target_log_flags;
+	int			error = 0;
+	uint64_t		f;
+	int			resblks = 0;
+	unsigned int		flags = 0;
+	struct timespec64	ctime;
+
+	/*
+	 * Lock the inodes against other IO, page faults and truncate to
+	 * begin with.  Then we can ensure the inodes are flushed and have no
+	 * page cache safely. Once we have done this we can take the ilocks and
+	 * do the rest of the checks.
+	 */
+	lock_two_nondirectories(VFS_I(ip), VFS_I(tip));
+	filemap_invalidate_lock_two(VFS_I(ip)->i_mapping,
+				    VFS_I(tip)->i_mapping);
+
+	/* Verify that both files have the same format */
+	if ((VFS_I(ip)->i_mode & S_IFMT) != (VFS_I(tip)->i_mode & S_IFMT)) {
+		error = -EINVAL;
+		goto out_unlock;
+	}
+
+	/* Verify both files are either real-time or non-realtime */
+	if (XFS_IS_REALTIME_INODE(ip) != XFS_IS_REALTIME_INODE(tip)) {
+		error = -EINVAL;
+		goto out_unlock;
+	}
+
+	error = xfs_qm_dqattach(ip);
+	if (error)
+		goto out_unlock;
+
+	error = xfs_qm_dqattach(tip);
+	if (error)
+		goto out_unlock;
+
+	error = xfs_swap_extent_flush(ip);
+	if (error)
+		goto out_unlock;
+	error = xfs_swap_extent_flush(tip);
+	if (error)
+		goto out_unlock;
+
+	if (xfs_inode_has_cow_data(tip)) {
+		error = xfs_reflink_cancel_cow_range(tip, 0, NULLFILEOFF, true);
+		if (error)
+			goto out_unlock;
+	}
+
+	/*
+	 * Extent "swapping" with rmap requires a permanent reservation and
+	 * a block reservation because it's really just a remap operation
+	 * performed with log redo items!
+	 */
+	if (xfs_has_rmapbt(mp)) {
+		int		w = XFS_DATA_FORK;
+		uint32_t	ipnext = ip->i_df.if_nextents;
+		uint32_t	tipnext	= tip->i_df.if_nextents;
+
+		/*
+		 * Conceptually this shouldn't affect the shape of either bmbt,
+		 * but since we atomically move extents one by one, we reserve
+		 * enough space to rebuild both trees.
+		 */
+		resblks = XFS_SWAP_RMAP_SPACE_RES(mp, ipnext, w);
+		resblks +=  XFS_SWAP_RMAP_SPACE_RES(mp, tipnext, w);
+
+		/*
+		 * If either inode straddles a bmapbt block allocation boundary,
+		 * the rmapbt algorithm triggers repeated allocs and frees as
+		 * extents are remapped. This can exhaust the block reservation
+		 * prematurely and cause shutdown. Return freed blocks to the
+		 * transaction reservation to counter this behavior.
+		 */
+		flags |= XFS_TRANS_RES_FDBLKS;
+	}
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, flags,
+				&tp);
+	if (error)
+		goto out_unlock;
+
+	/*
+	 * Lock and join the inodes to the tansaction so that transaction commit
+	 * or cancel will unlock the inodes from this point onwards.
+	 */
+	xfs_lock_two_inodes(ip, XFS_ILOCK_EXCL, tip, XFS_ILOCK_EXCL);
+	xfs_trans_ijoin(tp, ip, 0);
+	xfs_trans_ijoin(tp, tip, 0);
+
+
+	/* Verify all data are being swapped */
+	if (sxp->sx_offset != 0 ||
+	    sxp->sx_length != ip->i_disk_size ||
+	    sxp->sx_length != tip->i_disk_size) {
+		error = -EFAULT;
+		goto out_trans_cancel;
+	}
+
+	trace_xfs_swap_extent_before(ip, 0);
+	trace_xfs_swap_extent_before(tip, 1);
+
+	/* check inode formats now that data is flushed */
+	error = xfs_swap_extents_check_format(ip, tip);
+	if (error) {
+		xfs_notice(mp,
+		    "%s: inode 0x%llx format is incompatible for exchanging.",
+				__func__, ip->i_ino);
+		goto out_trans_cancel;
+	}
+
+	/*
+	 * Compare the current change & modify times with that
+	 * passed in.  If they differ, we abort this swap.
+	 * This is the mechanism used to ensure the calling
+	 * process that the file was not changed out from
+	 * under it.
+	 */
+	ctime = inode_get_ctime(VFS_I(ip));
+	if ((sbp->bs_ctime.tv_sec != ctime.tv_sec) ||
+	    (sbp->bs_ctime.tv_nsec != ctime.tv_nsec) ||
+	    (sbp->bs_mtime.tv_sec != VFS_I(ip)->i_mtime.tv_sec) ||
+	    (sbp->bs_mtime.tv_nsec != VFS_I(ip)->i_mtime.tv_nsec)) {
+		error = -EBUSY;
+		goto out_trans_cancel;
+	}
+
+	/*
+	 * Note the trickiness in setting the log flags - we set the owner log
+	 * flag on the opposite inode (i.e. the inode we are setting the new
+	 * owner to be) because once we swap the forks and log that, log
+	 * recovery is going to see the fork as owned by the swapped inode,
+	 * not the pre-swapped inodes.
+	 */
+	src_log_flags = XFS_ILOG_CORE;
+	target_log_flags = XFS_ILOG_CORE;
+
+	if (xfs_has_rmapbt(mp))
+		error = xfs_swap_extent_rmap(&tp, ip, tip);
+	else
+		error = xfs_swap_extent_forks(tp, ip, tip, &src_log_flags,
+				&target_log_flags);
+	if (error)
+		goto out_trans_cancel;
+
+	/* Do we have to swap reflink flags? */
+	if ((ip->i_diflags2 & XFS_DIFLAG2_REFLINK) ^
+	    (tip->i_diflags2 & XFS_DIFLAG2_REFLINK)) {
+		f = ip->i_diflags2 & XFS_DIFLAG2_REFLINK;
+		ip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK;
+		ip->i_diflags2 |= tip->i_diflags2 & XFS_DIFLAG2_REFLINK;
+		tip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK;
+		tip->i_diflags2 |= f & XFS_DIFLAG2_REFLINK;
+	}
+
+	/* Swap the cow forks. */
+	if (xfs_has_reflink(mp)) {
+		ASSERT(!ip->i_cowfp ||
+		       ip->i_cowfp->if_format == XFS_DINODE_FMT_EXTENTS);
+		ASSERT(!tip->i_cowfp ||
+		       tip->i_cowfp->if_format == XFS_DINODE_FMT_EXTENTS);
+
+		swap(ip->i_cowfp, tip->i_cowfp);
+
+		if (ip->i_cowfp && ip->i_cowfp->if_bytes)
+			xfs_inode_set_cowblocks_tag(ip);
+		else
+			xfs_inode_clear_cowblocks_tag(ip);
+		if (tip->i_cowfp && tip->i_cowfp->if_bytes)
+			xfs_inode_set_cowblocks_tag(tip);
+		else
+			xfs_inode_clear_cowblocks_tag(tip);
+	}
+
+	xfs_trans_log_inode(tp, ip,  src_log_flags);
+	xfs_trans_log_inode(tp, tip, target_log_flags);
+
+	/*
+	 * The extent forks have been swapped, but crc=1,rmapbt=0 filesystems
+	 * have inode number owner values in the bmbt blocks that still refer to
+	 * the old inode. Scan each bmbt to fix up the owner values with the
+	 * inode number of the current inode.
+	 */
+	if (src_log_flags & XFS_ILOG_DOWNER) {
+		error = xfs_swap_change_owner(&tp, ip, tip);
+		if (error)
+			goto out_trans_cancel;
+	}
+	if (target_log_flags & XFS_ILOG_DOWNER) {
+		error = xfs_swap_change_owner(&tp, tip, ip);
+		if (error)
+			goto out_trans_cancel;
+	}
+
+	/*
+	 * If this is a synchronous mount, make sure that the
+	 * transaction goes to disk before returning to the user.
+	 */
+	if (xfs_has_wsync(mp))
+		xfs_trans_set_sync(tp);
+
+	error = xfs_trans_commit(tp);
+
+	trace_xfs_swap_extent_after(ip, 0);
+	trace_xfs_swap_extent_after(tip, 1);
+
+out_unlock_ilock:
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	xfs_iunlock(tip, XFS_ILOCK_EXCL);
+out_unlock:
+	filemap_invalidate_unlock_two(VFS_I(ip)->i_mapping,
+				      VFS_I(tip)->i_mapping);
+	unlock_two_nondirectories(VFS_I(ip), VFS_I(tip));
+	return error;
+
+out_trans_cancel:
+	xfs_trans_cancel(tp);
+	goto out_unlock_ilock;
+}