Sync up libxfs to latest kernel code

[thirdparty/xfsprogs-dev.git] / libxfs / xfs_inode.c

/*
 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <xfs.h>

kmem_zone_t *xfs_ifork_zone;
kmem_zone_t *xfs_inode_zone;

STATIC int xfs_iformat_local(xfs_inode_t *, xfs_dinode_t *, int, int);
STATIC int xfs_iformat_extents(xfs_inode_t *, xfs_dinode_t *, int);
STATIC int xfs_iformat_btree(xfs_inode_t *, xfs_dinode_t *, int);

#ifdef DEBUG
/*
 * Make sure that the extents in the given memory buffer
 * are valid.
 */
STATIC void
xfs_validate_extents(
	xfs_ifork_t		*ifp,
	int			nrecs,
	xfs_exntfmt_t		fmt)
{
	xfs_bmbt_irec_t		irec;
	xfs_bmbt_rec_host_t	rec;
	int			i;

	for (i = 0; i < nrecs; i++) {
		xfs_bmbt_rec_host_t *ep = xfs_iext_get_ext(ifp, i);
		rec.l0 = get_unaligned(&ep->l0);
		rec.l1 = get_unaligned(&ep->l1);
		xfs_bmbt_get_all(&rec, &irec);
		if (fmt == XFS_EXTFMT_NOSTATE)
			ASSERT(irec.br_state == XFS_EXT_NORM);
	}
}
#else /* DEBUG */
#define xfs_validate_extents(ifp, nrecs, fmt)
#endif /* DEBUG */

/*
 * Check that none of the inode's in the buffer have a next
 * unlinked field of 0.
 */
#if defined(DEBUG)
void
xfs_inobp_check(
	xfs_mount_t	*mp,
	xfs_buf_t	*bp)
{
	int		i;
	int		j;
	xfs_dinode_t	*dip;

	j = mp->m_inode_cluster_size >> mp->m_sb.sb_inodelog;

	for (i = 0; i < j; i++) {
		dip = (xfs_dinode_t *)xfs_buf_offset(bp,
					i * mp->m_sb.sb_inodesize);
		if (!dip->di_next_unlinked)  {
			xfs_fs_cmn_err(CE_ALERT, mp,
				"Detected a bogus zero next_unlinked field in incore inode buffer 0x%p.  About to pop an ASSERT.",
				bp);
			ASSERT(dip->di_next_unlinked);
		}
	}
}
#endif

/*
 * Find the buffer associated with the given inode map
 * We do basic validation checks on the buffer once it has been
 * retrieved from disk.
 */
STATIC int
xfs_imap_to_bp(
	xfs_mount_t	*mp,
	xfs_trans_t	*tp,
	xfs_imap_t	*imap,
	xfs_buf_t	**bpp,
	uint		buf_flags,
	uint		imap_flags)
{
	int		error;
	int		i;
	int		ni;
	xfs_buf_t	*bp;

	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, imap->im_blkno,
				   (int)imap->im_len, buf_flags, &bp);
	if (error) {
		if (error != EAGAIN) {
			cmn_err(CE_WARN,
				"xfs_imap_to_bp: xfs_trans_read_buf()returned "
				"an error %d on %s.  Returning error.",
				error, mp->m_fsname);
		} else {
			ASSERT(buf_flags & XFS_BUF_TRYLOCK);
		}
		return error;
	}

	/*
	 * Validate the magic number and version of every inode in the buffer
	 * (if DEBUG kernel) or the first inode in the buffer, otherwise.
	 */
#ifdef DEBUG
	ni = BBTOB(imap->im_len) >> mp->m_sb.sb_inodelog;
#else	/* usual case */
	ni = 1;
#endif

	for (i = 0; i < ni; i++) {
		int		di_ok;
		xfs_dinode_t	*dip;

		dip = (xfs_dinode_t *)xfs_buf_offset(bp,
					(i << mp->m_sb.sb_inodelog));
		di_ok = be16_to_cpu(dip->di_core.di_magic) == XFS_DINODE_MAGIC &&
			    XFS_DINODE_GOOD_VERSION(dip->di_core.di_version);
		if (unlikely(XFS_TEST_ERROR(!di_ok, mp,
						XFS_ERRTAG_ITOBP_INOTOBP,
						XFS_RANDOM_ITOBP_INOTOBP))) {
			if (imap_flags & XFS_IMAP_BULKSTAT) {
				xfs_trans_brelse(tp, bp);
				return XFS_ERROR(EINVAL);
			}
			XFS_CORRUPTION_ERROR("xfs_imap_to_bp",
						XFS_ERRLEVEL_HIGH, mp, dip);
#ifdef DEBUG
			cmn_err(CE_PANIC,
					"Device %s - bad inode magic/vsn "
					"daddr %lld #%d (magic=%x)",
				XFS_BUFTARG_NAME(mp->m_ddev_targp),
				(unsigned long long)imap->im_blkno, i,
				be16_to_cpu(dip->di_core.di_magic));
#endif
			xfs_trans_brelse(tp, bp);
			return XFS_ERROR(EFSCORRUPTED);
		}
	}

	xfs_inobp_check(mp, bp);

	/*
	 * Mark the buffer as an inode buffer now that it looks good
	 */
	XFS_BUF_SET_VTYPE(bp, B_FS_INO);

	*bpp = bp;
	return 0;
}

/*
 * This routine is called to map an inode to the buffer containing
 * the on-disk version of the inode.  It returns a pointer to the
 * buffer containing the on-disk inode in the bpp parameter, and in
 * the dip parameter it returns a pointer to the on-disk inode within
 * that buffer.
 *
 * If a non-zero error is returned, then the contents of bpp and
 * dipp are undefined.
 *
 * If the inode is new and has not yet been initialized, use xfs_imap()
 * to determine the size and location of the buffer to read from disk.
 * If the inode has already been mapped to its buffer and read in once,
 * then use the mapping information stored in the inode rather than
 * calling xfs_imap().  This allows us to avoid the overhead of looking
 * at the inode btree for small block file systems (see xfs_dilocate()).
 * We can tell whether the inode has been mapped in before by comparing
 * its disk block address to 0.  Only uninitialized inodes will have
 * 0 for the disk block address.
 */
int
xfs_itobp(
	xfs_mount_t	*mp,
	xfs_trans_t	*tp,
	xfs_inode_t	*ip,
	xfs_dinode_t	**dipp,
	xfs_buf_t	**bpp,
	xfs_daddr_t	bno,
	uint		imap_flags,
	uint		buf_flags)
{
	xfs_imap_t	imap;
	xfs_buf_t	*bp;
	int		error;

	if (ip->i_blkno == (xfs_daddr_t)0) {
		imap.im_blkno = bno;
		error = xfs_imap(mp, tp, ip->i_ino, &imap,
					XFS_IMAP_LOOKUP | imap_flags);
		if (error)
			return error;

		/*
		 * Fill in the fields in the inode that will be used to
		 * map the inode to its buffer from now on.
		 */
		ip->i_blkno = imap.im_blkno;
		ip->i_len = imap.im_len;
		ip->i_boffset = imap.im_boffset;
	} else {
		/*
		 * We've already mapped the inode once, so just use the
		 * mapping that we saved the first time.
		 */
		imap.im_blkno = ip->i_blkno;
		imap.im_len = ip->i_len;
		imap.im_boffset = ip->i_boffset;
	}
	ASSERT(bno == 0 || bno == imap.im_blkno);

	error = xfs_imap_to_bp(mp, tp, &imap, &bp, buf_flags, imap_flags);
	if (error)
		return error;

	if (!bp) {
		ASSERT(buf_flags & XFS_BUF_TRYLOCK);
		ASSERT(tp == NULL);
		*bpp = NULL;
		return EAGAIN;
	}

	*dipp = (xfs_dinode_t *)xfs_buf_offset(bp, imap.im_boffset);
	*bpp = bp;
	return 0;
}

/*
 * Move inode type and inode format specific information from the
 * on-disk inode to the in-core inode.  For fifos, devs, and sockets
 * this means set if_rdev to the proper value.  For files, directories,
 * and symlinks this means to bring in the in-line data or extent
 * pointers.  For a file in B-tree format, only the root is immediately
 * brought in-core.  The rest will be in-lined in if_extents when it
 * is first referenced (see xfs_iread_extents()).
 *
 * Note: this requires user-space public scope for libxfs_iread
 */
int
xfs_iformat(
	xfs_inode_t		*ip,
	xfs_dinode_t		*dip)
{
	xfs_attr_shortform_t	*atp;
	int			size;
	int			error;
	xfs_fsize_t             di_size;
	ip->i_df.if_ext_max =
		XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t);
	error = 0;

	if (unlikely(be32_to_cpu(dip->di_core.di_nextents) +
		     be16_to_cpu(dip->di_core.di_anextents) >
		     be64_to_cpu(dip->di_core.di_nblocks))) {
		xfs_fs_repair_cmn_err(CE_WARN, ip->i_mount,
			"corrupt dinode %Lu, extent total = %d, nblocks = %Lu.",
			(unsigned long long)ip->i_ino,
			(int)(be32_to_cpu(dip->di_core.di_nextents) +
			      be16_to_cpu(dip->di_core.di_anextents)),
			(unsigned long long)
				be64_to_cpu(dip->di_core.di_nblocks));
		XFS_CORRUPTION_ERROR("xfs_iformat(1)", XFS_ERRLEVEL_LOW,
				     ip->i_mount, dip);
		return XFS_ERROR(EFSCORRUPTED);
	}

	if (unlikely(dip->di_core.di_forkoff > ip->i_mount->m_sb.sb_inodesize)) {
		xfs_fs_repair_cmn_err(CE_WARN, ip->i_mount,
			"corrupt dinode %Lu, forkoff = 0x%x.",
			(unsigned long long)ip->i_ino,
			dip->di_core.di_forkoff);
		XFS_CORRUPTION_ERROR("xfs_iformat(2)", XFS_ERRLEVEL_LOW,
				     ip->i_mount, dip);
		return XFS_ERROR(EFSCORRUPTED);
	}

	switch (ip->i_d.di_mode & S_IFMT) {
	case S_IFIFO:
	case S_IFCHR:
	case S_IFBLK:
	case S_IFSOCK:
		if (unlikely(dip->di_core.di_format != XFS_DINODE_FMT_DEV)) {
			XFS_CORRUPTION_ERROR("xfs_iformat(3)", XFS_ERRLEVEL_LOW,
					      ip->i_mount, dip);
			return XFS_ERROR(EFSCORRUPTED);
		}
		ip->i_d.di_size = 0;
		ip->i_size = 0;
		ip->i_df.if_u2.if_rdev = be32_to_cpu(dip->di_u.di_dev);
		break;

	case S_IFREG:
	case S_IFLNK:
	case S_IFDIR:
		switch (dip->di_core.di_format) {
		case XFS_DINODE_FMT_LOCAL:
			/*
			 * no local regular files yet
			 */
			if (unlikely((be16_to_cpu(dip->di_core.di_mode) & S_IFMT) == S_IFREG)) {
				xfs_fs_repair_cmn_err(CE_WARN, ip->i_mount,
					"corrupt inode %Lu "
					"(local format for regular file).",
					(unsigned long long) ip->i_ino);
				XFS_CORRUPTION_ERROR("xfs_iformat(4)",
						     XFS_ERRLEVEL_LOW,
						     ip->i_mount, dip);
				return XFS_ERROR(EFSCORRUPTED);
			}

			di_size = be64_to_cpu(dip->di_core.di_size);
			if (unlikely(di_size > XFS_DFORK_DSIZE(dip, ip->i_mount))) {
				xfs_fs_repair_cmn_err(CE_WARN, ip->i_mount,
					"corrupt inode %Lu "
					"(bad size %Ld for local inode).",
					(unsigned long long) ip->i_ino,
					(long long) di_size);
				XFS_CORRUPTION_ERROR("xfs_iformat(5)",
						     XFS_ERRLEVEL_LOW,
						     ip->i_mount, dip);
				return XFS_ERROR(EFSCORRUPTED);
			}

			size = (int)di_size;
			error = xfs_iformat_local(ip, dip, XFS_DATA_FORK, size);
			break;
		case XFS_DINODE_FMT_EXTENTS:
			error = xfs_iformat_extents(ip, dip, XFS_DATA_FORK);
			break;
		case XFS_DINODE_FMT_BTREE:
			error = xfs_iformat_btree(ip, dip, XFS_DATA_FORK);
			break;
		default:
			XFS_ERROR_REPORT("xfs_iformat(6)", XFS_ERRLEVEL_LOW,
					 ip->i_mount);
			return XFS_ERROR(EFSCORRUPTED);
		}
		break;

	default:
		XFS_ERROR_REPORT("xfs_iformat(7)", XFS_ERRLEVEL_LOW, ip->i_mount);
		return XFS_ERROR(EFSCORRUPTED);
	}
	if (error) {
		return error;
	}
	if (!XFS_DFORK_Q(dip))
		return 0;
	ASSERT(ip->i_afp == NULL);
	ip->i_afp = kmem_zone_zalloc(xfs_ifork_zone, KM_SLEEP);
	ip->i_afp->if_ext_max =
		XFS_IFORK_ASIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t);
	switch (dip->di_core.di_aformat) {
	case XFS_DINODE_FMT_LOCAL:
		atp = (xfs_attr_shortform_t *)XFS_DFORK_APTR(dip);
		size = be16_to_cpu(atp->hdr.totsize);
		error = xfs_iformat_local(ip, dip, XFS_ATTR_FORK, size);
		break;
	case XFS_DINODE_FMT_EXTENTS:
		error = xfs_iformat_extents(ip, dip, XFS_ATTR_FORK);
		break;
	case XFS_DINODE_FMT_BTREE:
		error = xfs_iformat_btree(ip, dip, XFS_ATTR_FORK);
		break;
	default:
		error = XFS_ERROR(EFSCORRUPTED);
		break;
	}
	if (error) {
		kmem_zone_free(xfs_ifork_zone, ip->i_afp);
		ip->i_afp = NULL;
		xfs_idestroy_fork(ip, XFS_DATA_FORK);
	}
	return error;
}

/*
 * The file is in-lined in the on-disk inode.
 * If it fits into if_inline_data, then copy
 * it there, otherwise allocate a buffer for it
 * and copy the data there.  Either way, set
 * if_data to point at the data.
 * If we allocate a buffer for the data, make
 * sure that its size is a multiple of 4 and
 * record the real size in i_real_bytes.
 */
STATIC int
xfs_iformat_local(
	xfs_inode_t	*ip,
	xfs_dinode_t	*dip,
	int		whichfork,
	int		size)
{
	xfs_ifork_t	*ifp;
	int		real_size;

	/*
	 * If the size is unreasonable, then something
	 * is wrong and we just bail out rather than crash in
	 * kmem_alloc() or memcpy() below.
	 */
	if (unlikely(size > XFS_DFORK_SIZE(dip, ip->i_mount, whichfork))) {
		xfs_fs_repair_cmn_err(CE_WARN, ip->i_mount,
			"corrupt inode %Lu "
			"(bad size %d for local fork, size = %d).",
			(unsigned long long) ip->i_ino, size,
			XFS_DFORK_SIZE(dip, ip->i_mount, whichfork));
		XFS_CORRUPTION_ERROR("xfs_iformat_local", XFS_ERRLEVEL_LOW,
				     ip->i_mount, dip);
		return XFS_ERROR(EFSCORRUPTED);
	}
	ifp = XFS_IFORK_PTR(ip, whichfork);
	real_size = 0;
	if (size == 0)
		ifp->if_u1.if_data = NULL;
	else if (size <= sizeof(ifp->if_u2.if_inline_data))
		ifp->if_u1.if_data = ifp->if_u2.if_inline_data;
	else {
		real_size = roundup(size, 4);
		ifp->if_u1.if_data = kmem_alloc(real_size, KM_SLEEP);
	}
	ifp->if_bytes = size;
	ifp->if_real_bytes = real_size;
	if (size)
		memcpy(ifp->if_u1.if_data, XFS_DFORK_PTR(dip, whichfork), size);
	ifp->if_flags &= ~XFS_IFEXTENTS;
	ifp->if_flags |= XFS_IFINLINE;
	return 0;
}

/*
 * The file consists of a set of extents all
 * of which fit into the on-disk inode.
 * If there are few enough extents to fit into
 * the if_inline_ext, then copy them there.
 * Otherwise allocate a buffer for them and copy
 * them into it.  Either way, set if_extents
 * to point at the extents.
 */
STATIC int
xfs_iformat_extents(
	xfs_inode_t	*ip,
	xfs_dinode_t	*dip,
	int		whichfork)
{
	xfs_bmbt_rec_t	*dp;
	xfs_ifork_t	*ifp;
	int		nex;
	int		size;
	int		i;

	ifp = XFS_IFORK_PTR(ip, whichfork);
	nex = XFS_DFORK_NEXTENTS(dip, whichfork);
	size = nex * (uint)sizeof(xfs_bmbt_rec_t);

	/*
	 * If the number of extents is unreasonable, then something
	 * is wrong and we just bail out rather than crash in
	 * kmem_alloc() or memcpy() below.
	 */
	if (unlikely(size < 0 || size > XFS_DFORK_SIZE(dip, ip->i_mount, whichfork))) {
		xfs_fs_repair_cmn_err(CE_WARN, ip->i_mount,
			"corrupt inode %Lu ((a)extents = %d).",
			(unsigned long long) ip->i_ino, nex);
		XFS_CORRUPTION_ERROR("xfs_iformat_extents(1)", XFS_ERRLEVEL_LOW,
				     ip->i_mount, dip);
		return XFS_ERROR(EFSCORRUPTED);
	}

	ifp->if_real_bytes = 0;
	if (nex == 0)
		ifp->if_u1.if_extents = NULL;
	else if (nex <= XFS_INLINE_EXTS)
		ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
	else
		xfs_iext_add(ifp, 0, nex);

	ifp->if_bytes = size;
	if (size) {
		dp = (xfs_bmbt_rec_t *) XFS_DFORK_PTR(dip, whichfork);
		xfs_validate_extents(ifp, nex, XFS_EXTFMT_INODE(ip));
		for (i = 0; i < nex; i++, dp++) {
			xfs_bmbt_rec_host_t *ep = xfs_iext_get_ext(ifp, i);
			ep->l0 = get_unaligned_be64(&dp->l0);
			ep->l1 = get_unaligned_be64(&dp->l1);
		}
		XFS_BMAP_TRACE_EXLIST(ip, nex, whichfork);
		if (whichfork != XFS_DATA_FORK ||
			XFS_EXTFMT_INODE(ip) == XFS_EXTFMT_NOSTATE)
				if (unlikely(xfs_check_nostate_extents(
				    ifp, 0, nex))) {
					XFS_ERROR_REPORT("xfs_iformat_extents(2)",
							 XFS_ERRLEVEL_LOW,
							 ip->i_mount);
					return XFS_ERROR(EFSCORRUPTED);
				}
	}
	ifp->if_flags |= XFS_IFEXTENTS;
	return 0;
}

/*
 * The file has too many extents to fit into
 * the inode, so they are in B-tree format.
 * Allocate a buffer for the root of the B-tree
 * and copy the root into it.  The i_extents
 * field will remain NULL until all of the
 * extents are read in (when they are needed).
 */
STATIC int
xfs_iformat_btree(
	xfs_inode_t		*ip,
	xfs_dinode_t		*dip,
	int			whichfork)
{
	xfs_bmdr_block_t	*dfp;
	xfs_ifork_t		*ifp;
	/* REFERENCED */
	int			nrecs;
	int			size;

	ifp = XFS_IFORK_PTR(ip, whichfork);
	dfp = (xfs_bmdr_block_t *)XFS_DFORK_PTR(dip, whichfork);
	size = XFS_BMAP_BROOT_SPACE(dfp);
	nrecs = be16_to_cpu(dfp->bb_numrecs);

	/*
	 * blow out if -- fork has less extents than can fit in
	 * fork (fork shouldn't be a btree format), root btree
	 * block has more records than can fit into the fork,
	 * or the number of extents is greater than the number of
	 * blocks.
	 */
	if (unlikely(XFS_IFORK_NEXTENTS(ip, whichfork) <= ifp->if_ext_max
	    || XFS_BMDR_SPACE_CALC(nrecs) >
			XFS_DFORK_SIZE(dip, ip->i_mount, whichfork)
	    || XFS_IFORK_NEXTENTS(ip, whichfork) > ip->i_d.di_nblocks)) {
		xfs_fs_repair_cmn_err(CE_WARN, ip->i_mount,
			"corrupt inode %Lu (btree).",
			(unsigned long long) ip->i_ino);
		XFS_ERROR_REPORT("xfs_iformat_btree", XFS_ERRLEVEL_LOW,
				 ip->i_mount);
		return XFS_ERROR(EFSCORRUPTED);
	}

	ifp->if_broot_bytes = size;
	ifp->if_broot = kmem_alloc(size, KM_SLEEP);
	ASSERT(ifp->if_broot != NULL);
	/*
	 * Copy and convert from the on-disk structure
	 * to the in-memory structure.
	 */
	xfs_bmdr_to_bmbt(ip->i_mount, dfp,
			 XFS_DFORK_SIZE(dip, ip->i_mount, whichfork),
			 ifp->if_broot, size);
	ifp->if_flags &= ~XFS_IFEXTENTS;
	ifp->if_flags |= XFS_IFBROOT;

	return 0;
}

void
xfs_dinode_from_disk(
	xfs_icdinode_t		*to,
	xfs_dinode_core_t	*from)
{
	to->di_magic = be16_to_cpu(from->di_magic);
	to->di_mode = be16_to_cpu(from->di_mode);
	to->di_version = from ->di_version;
	to->di_format = from->di_format;
	to->di_onlink = be16_to_cpu(from->di_onlink);
	to->di_uid = be32_to_cpu(from->di_uid);
	to->di_gid = be32_to_cpu(from->di_gid);
	to->di_nlink = be32_to_cpu(from->di_nlink);
	to->di_projid = be16_to_cpu(from->di_projid);
	memcpy(to->di_pad, from->di_pad, sizeof(to->di_pad));
	to->di_flushiter = be16_to_cpu(from->di_flushiter);
	to->di_atime.t_sec = be32_to_cpu(from->di_atime.t_sec);
	to->di_atime.t_nsec = be32_to_cpu(from->di_atime.t_nsec);
	to->di_mtime.t_sec = be32_to_cpu(from->di_mtime.t_sec);
	to->di_mtime.t_nsec = be32_to_cpu(from->di_mtime.t_nsec);
	to->di_ctime.t_sec = be32_to_cpu(from->di_ctime.t_sec);
	to->di_ctime.t_nsec = be32_to_cpu(from->di_ctime.t_nsec);
	to->di_size = be64_to_cpu(from->di_size);
	to->di_nblocks = be64_to_cpu(from->di_nblocks);
	to->di_extsize = be32_to_cpu(from->di_extsize);
	to->di_nextents = be32_to_cpu(from->di_nextents);
	to->di_anextents = be16_to_cpu(from->di_anextents);
	to->di_forkoff = from->di_forkoff;
	to->di_aformat	= from->di_aformat;
	to->di_dmevmask	= be32_to_cpu(from->di_dmevmask);
	to->di_dmstate	= be16_to_cpu(from->di_dmstate);
	to->di_flags	= be16_to_cpu(from->di_flags);
	to->di_gen	= be32_to_cpu(from->di_gen);
}

void
xfs_dinode_to_disk(
	xfs_dinode_core_t	*to,
	xfs_icdinode_t		*from)
{
	to->di_magic = cpu_to_be16(from->di_magic);
	to->di_mode = cpu_to_be16(from->di_mode);
	to->di_version = from ->di_version;
	to->di_format = from->di_format;
	to->di_onlink = cpu_to_be16(from->di_onlink);
	to->di_uid = cpu_to_be32(from->di_uid);
	to->di_gid = cpu_to_be32(from->di_gid);
	to->di_nlink = cpu_to_be32(from->di_nlink);
	to->di_projid = cpu_to_be16(from->di_projid);
	memcpy(to->di_pad, from->di_pad, sizeof(to->di_pad));
	to->di_flushiter = cpu_to_be16(from->di_flushiter);
	to->di_atime.t_sec = cpu_to_be32(from->di_atime.t_sec);
	to->di_atime.t_nsec = cpu_to_be32(from->di_atime.t_nsec);
	to->di_mtime.t_sec = cpu_to_be32(from->di_mtime.t_sec);
	to->di_mtime.t_nsec = cpu_to_be32(from->di_mtime.t_nsec);
	to->di_ctime.t_sec = cpu_to_be32(from->di_ctime.t_sec);
	to->di_ctime.t_nsec = cpu_to_be32(from->di_ctime.t_nsec);
	to->di_size = cpu_to_be64(from->di_size);
	to->di_nblocks = cpu_to_be64(from->di_nblocks);
	to->di_extsize = cpu_to_be32(from->di_extsize);
	to->di_nextents = cpu_to_be32(from->di_nextents);
	to->di_anextents = cpu_to_be16(from->di_anextents);
	to->di_forkoff = from->di_forkoff;
	to->di_aformat = from->di_aformat;
	to->di_dmevmask = cpu_to_be32(from->di_dmevmask);
	to->di_dmstate = cpu_to_be16(from->di_dmstate);
	to->di_flags = cpu_to_be16(from->di_flags);
	to->di_gen = cpu_to_be32(from->di_gen);
}

/*
 * Read in extents from a btree-format inode.
 * Allocate and fill in if_extents.  Real work is done in xfs_bmap.c.
 */
int
xfs_iread_extents(
	xfs_trans_t	*tp,
	xfs_inode_t	*ip,
	int		whichfork)
{
	int		error;
	xfs_ifork_t	*ifp;
	xfs_extnum_t	nextents;
	size_t		size;

	if (unlikely(XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE)) {
		XFS_ERROR_REPORT("xfs_iread_extents", XFS_ERRLEVEL_LOW,
				 ip->i_mount);
		return XFS_ERROR(EFSCORRUPTED);
	}
	nextents = XFS_IFORK_NEXTENTS(ip, whichfork);
	size = nextents * sizeof(xfs_bmbt_rec_t);
	ifp = XFS_IFORK_PTR(ip, whichfork);

	/*
	 * We know that the size is valid (it's checked in iformat_btree)
	 */
	ifp->if_lastex = NULLEXTNUM;
	ifp->if_bytes = ifp->if_real_bytes = 0;
	ifp->if_flags |= XFS_IFEXTENTS;
	xfs_iext_add(ifp, 0, nextents);
	error = xfs_bmap_read_extents(tp, ip, whichfork);
	if (error) {
		xfs_iext_destroy(ifp);
		ifp->if_flags &= ~XFS_IFEXTENTS;
		return error;
	}
	xfs_validate_extents(ifp, nextents, XFS_EXTFMT_INODE(ip));
	return 0;
}

/*
 * Reallocate the space for if_broot based on the number of records
 * being added or deleted as indicated in rec_diff.  Move the records
 * and pointers in if_broot to fit the new size.  When shrinking this
 * will eliminate holes between the records and pointers created by
 * the caller.  When growing this will create holes to be filled in
 * by the caller.
 *
 * The caller must not request to add more records than would fit in
 * the on-disk inode root.  If the if_broot is currently NULL, then
 * if we adding records one will be allocated.  The caller must also
 * not request that the number of records go below zero, although
 * it can go to zero.
 *
 * ip -- the inode whose if_broot area is changing
 * ext_diff -- the change in the number of records, positive or negative,
 *	 requested for the if_broot array.
 */
void
xfs_iroot_realloc(
	xfs_inode_t		*ip,
	int			rec_diff,
	int			whichfork)
{
	struct xfs_mount	*mp = ip->i_mount;
	int			cur_max;
	xfs_ifork_t		*ifp;
	struct xfs_btree_block	*new_broot;
	int			new_max;
	size_t			new_size;
	char			*np;
	char			*op;

	/*
	 * Handle the degenerate case quietly.
	 */
	if (rec_diff == 0) {
		return;
	}

	ifp = XFS_IFORK_PTR(ip, whichfork);
	if (rec_diff > 0) {
		/*
		 * If there wasn't any memory allocated before, just
		 * allocate it now and get out.
		 */
		if (ifp->if_broot_bytes == 0) {
			new_size = (size_t)XFS_BMAP_BROOT_SPACE_CALC(rec_diff);
			ifp->if_broot = kmem_alloc(new_size, KM_SLEEP);
			ifp->if_broot_bytes = (int)new_size;
			return;
		}

		/*
		 * If there is already an existing if_broot, then we need
		 * to realloc() it and shift the pointers to their new
		 * location.  The records don't change location because
		 * they are kept butted up against the btree block header.
		 */
		cur_max = xfs_bmbt_maxrecs(mp, ifp->if_broot_bytes, 0);
		new_max = cur_max + rec_diff;
		new_size = (size_t)XFS_BMAP_BROOT_SPACE_CALC(new_max);
		ifp->if_broot = kmem_realloc(ifp->if_broot, new_size,
				(size_t)XFS_BMAP_BROOT_SPACE_CALC(cur_max), /* old size */
				KM_SLEEP);
		op = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, ifp->if_broot, 1,
						     ifp->if_broot_bytes);
		np = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, ifp->if_broot, 1,
						     (int)new_size);
		ifp->if_broot_bytes = (int)new_size;
		ASSERT(ifp->if_broot_bytes <=
			XFS_IFORK_SIZE(ip, whichfork) + XFS_BROOT_SIZE_ADJ);
		memmove(np, op, cur_max * (uint)sizeof(xfs_dfsbno_t));
		return;
	}

	/*
	 * rec_diff is less than 0.  In this case, we are shrinking the
	 * if_broot buffer.  It must already exist.  If we go to zero
	 * records, just get rid of the root and clear the status bit.
	 */
	ASSERT((ifp->if_broot != NULL) && (ifp->if_broot_bytes > 0));
	cur_max = xfs_bmbt_maxrecs(mp, ifp->if_broot_bytes, 0);
	new_max = cur_max + rec_diff;
	ASSERT(new_max >= 0);
	if (new_max > 0)
		new_size = (size_t)XFS_BMAP_BROOT_SPACE_CALC(new_max);
	else
		new_size = 0;
	if (new_size > 0) {
		new_broot = kmem_alloc(new_size, KM_SLEEP);
		/*
		 * First copy over the btree block header.
		 */
		memcpy(new_broot, ifp->if_broot, XFS_BTREE_LBLOCK_LEN);
	} else {
		new_broot = NULL;
		ifp->if_flags &= ~XFS_IFBROOT;
	}

	/*
	 * Only copy the records and pointers if there are any.
	 */
	if (new_max > 0) {
		/*
		 * First copy the records.
		 */
		op = (char *)XFS_BMBT_REC_ADDR(mp, ifp->if_broot, 1);
		np = (char *)XFS_BMBT_REC_ADDR(mp, new_broot, 1);
		memcpy(np, op, new_max * (uint)sizeof(xfs_bmbt_rec_t));

		/*
		 * Then copy the pointers.
		 */
		op = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, ifp->if_broot, 1,
						     ifp->if_broot_bytes);
		np = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, new_broot, 1,
						     (int)new_size);
		memcpy(np, op, new_max * (uint)sizeof(xfs_dfsbno_t));
	}
	kmem_free(ifp->if_broot);
	ifp->if_broot = new_broot;
	ifp->if_broot_bytes = (int)new_size;
	ASSERT(ifp->if_broot_bytes <=
		XFS_IFORK_SIZE(ip, whichfork) + XFS_BROOT_SIZE_ADJ);
	return;
}


/*
 * This is called when the amount of space needed for if_data
 * is increased or decreased.  The change in size is indicated by
 * the number of bytes that need to be added or deleted in the
 * byte_diff parameter.
 *
 * If the amount of space needed has decreased below the size of the
 * inline buffer, then switch to using the inline buffer.  Otherwise,
 * use kmem_realloc() or kmem_alloc() to adjust the size of the buffer
 * to what is needed.
 *
 * ip -- the inode whose if_data area is changing
 * byte_diff -- the change in the number of bytes, positive or negative,
 *	 requested for the if_data array.
 */
void
xfs_idata_realloc(
	xfs_inode_t	*ip,
	int		byte_diff,
	int		whichfork)
{
	xfs_ifork_t	*ifp;
	int		new_size;
	int		real_size;

	if (byte_diff == 0) {
		return;
	}

	ifp = XFS_IFORK_PTR(ip, whichfork);
	new_size = (int)ifp->if_bytes + byte_diff;
	ASSERT(new_size >= 0);

	if (new_size == 0) {
		if (ifp->if_u1.if_data != ifp->if_u2.if_inline_data) {
			kmem_free(ifp->if_u1.if_data);
		}
		ifp->if_u1.if_data = NULL;
		real_size = 0;
	} else if (new_size <= sizeof(ifp->if_u2.if_inline_data)) {
		/*
		 * If the valid extents/data can fit in if_inline_ext/data,
		 * copy them from the malloc'd vector and free it.
		 */
		if (ifp->if_u1.if_data == NULL) {
			ifp->if_u1.if_data = ifp->if_u2.if_inline_data;
		} else if (ifp->if_u1.if_data != ifp->if_u2.if_inline_data) {
			ASSERT(ifp->if_real_bytes != 0);
			memcpy(ifp->if_u2.if_inline_data, ifp->if_u1.if_data,
			      new_size);
			kmem_free(ifp->if_u1.if_data);
			ifp->if_u1.if_data = ifp->if_u2.if_inline_data;
		}
		real_size = 0;
	} else {
		/*
		 * Stuck with malloc/realloc.
		 * For inline data, the underlying buffer must be
		 * a multiple of 4 bytes in size so that it can be
		 * logged and stay on word boundaries.  We enforce
		 * that here.
		 */
		real_size = roundup(new_size, 4);
		if (ifp->if_u1.if_data == NULL) {
			ASSERT(ifp->if_real_bytes == 0);
			ifp->if_u1.if_data = kmem_alloc(real_size, KM_SLEEP);
		} else if (ifp->if_u1.if_data != ifp->if_u2.if_inline_data) {
			/*
			 * Only do the realloc if the underlying size
			 * is really changing.
			 */
			if (ifp->if_real_bytes != real_size) {
				ifp->if_u1.if_data =
					kmem_realloc(ifp->if_u1.if_data,
							real_size,
							ifp->if_real_bytes,
							KM_SLEEP);
			}
		} else {
			ASSERT(ifp->if_real_bytes == 0);
			ifp->if_u1.if_data = kmem_alloc(real_size, KM_SLEEP);
			memcpy(ifp->if_u1.if_data, ifp->if_u2.if_inline_data,
				ifp->if_bytes);
		}
	}
	ifp->if_real_bytes = real_size;
	ifp->if_bytes = new_size;
	ASSERT(ifp->if_bytes <= XFS_IFORK_SIZE(ip, whichfork));
}




/*
 * Map inode to disk block and offset.
 *
 * mp -- the mount point structure for the current file system
 * tp -- the current transaction
 * ino -- the inode number of the inode to be located
 * imap -- this structure is filled in with the information necessary
 *	 to retrieve the given inode from disk
 * flags -- flags to pass to xfs_dilocate indicating whether or not
 *	 lookups in the inode btree were OK or not
 */
int
xfs_imap(
	xfs_mount_t	*mp,
	xfs_trans_t	*tp,
	xfs_ino_t	ino,
	xfs_imap_t	*imap,
	uint		flags)
{
	xfs_fsblock_t	fsbno;
	int		len;
	int		off;
	int		error;

	fsbno = imap->im_blkno ?
		XFS_DADDR_TO_FSB(mp, imap->im_blkno) : NULLFSBLOCK;
	error = xfs_dilocate(mp, tp, ino, &fsbno, &len, &off, flags);
	if (error)
		return error;

	imap->im_blkno = XFS_FSB_TO_DADDR(mp, fsbno);
	imap->im_len = XFS_FSB_TO_BB(mp, len);
	imap->im_agblkno = XFS_FSB_TO_AGBNO(mp, fsbno);
	imap->im_ioffset = (ushort)off;
	imap->im_boffset = (ushort)(off << mp->m_sb.sb_inodelog);

	/*
	 * If the inode number maps to a block outside the bounds
	 * of the file system then return NULL rather than calling
	 * read_buf and panicing when we get an error from the
	 * driver.
	 */
	if ((imap->im_blkno + imap->im_len) >
	    XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)) {
		xfs_fs_cmn_err(CE_ALERT, mp, "xfs_imap: "
			"(imap->im_blkno (0x%llx) + imap->im_len (0x%llx)) > "
			" XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) (0x%llx)",
			(unsigned long long) imap->im_blkno,
			(unsigned long long) imap->im_len,
			XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks));
		return EINVAL;
	}
	return 0;
}

void
xfs_idestroy_fork(
	xfs_inode_t	*ip,
	int		whichfork)
{
	xfs_ifork_t	*ifp;

	ifp = XFS_IFORK_PTR(ip, whichfork);
	if (ifp->if_broot != NULL) {
		kmem_free(ifp->if_broot);
		ifp->if_broot = NULL;
	}

	/*
	 * If the format is local, then we can't have an extents
	 * array so just look for an inline data array.  If we're
	 * not local then we may or may not have an extents list,
	 * so check and free it up if we do.
	 */
	if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL) {
		if ((ifp->if_u1.if_data != ifp->if_u2.if_inline_data) &&
		    (ifp->if_u1.if_data != NULL)) {
			ASSERT(ifp->if_real_bytes != 0);
			kmem_free(ifp->if_u1.if_data);
			ifp->if_u1.if_data = NULL;
			ifp->if_real_bytes = 0;
		}
	} else if ((ifp->if_flags & XFS_IFEXTENTS) &&
		   ((ifp->if_flags & XFS_IFEXTIREC) ||
		    ((ifp->if_u1.if_extents != NULL) &&
		     (ifp->if_u1.if_extents != ifp->if_u2.if_inline_ext)))) {
		ASSERT(ifp->if_real_bytes != 0);
		xfs_iext_destroy(ifp);
	}
	ASSERT(ifp->if_u1.if_extents == NULL ||
	       ifp->if_u1.if_extents == ifp->if_u2.if_inline_ext);
	ASSERT(ifp->if_real_bytes == 0);
	if (whichfork == XFS_ATTR_FORK) {
		kmem_zone_free(xfs_ifork_zone, ip->i_afp);
		ip->i_afp = NULL;
	}
}

/*
 * xfs_iextents_copy()
 *
 * This is called to copy the REAL extents (as opposed to the delayed
 * allocation extents) from the inode into the given buffer.  It
 * returns the number of bytes copied into the buffer.
 *
 * If there are no delayed allocation extents, then we can just
 * memcpy() the extents into the buffer.  Otherwise, we need to
 * examine each extent in turn and skip those which are delayed.
 */
int
xfs_iextents_copy(
	xfs_inode_t		*ip,
	xfs_bmbt_rec_t		*dp,
	int			whichfork)
{
	int			copied;
	int			i;
	xfs_ifork_t		*ifp;
	int			nrecs;
	xfs_fsblock_t		start_block;

	ifp = XFS_IFORK_PTR(ip, whichfork);
	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
	ASSERT(ifp->if_bytes > 0);

	nrecs = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	XFS_BMAP_TRACE_EXLIST(ip, nrecs, whichfork);
	ASSERT(nrecs > 0);

	/*
	 * There are some delayed allocation extents in the
	 * inode, so copy the extents one at a time and skip
	 * the delayed ones.  There must be at least one
	 * non-delayed extent.
	 */
	copied = 0;
	for (i = 0; i < nrecs; i++) {
		xfs_bmbt_rec_host_t *ep = xfs_iext_get_ext(ifp, i);
		start_block = xfs_bmbt_get_startblock(ep);
		if (ISNULLSTARTBLOCK(start_block)) {
			/*
			 * It's a delayed allocation extent, so skip it.
			 */
			continue;
		}

		/* Translate to on disk format */
		put_unaligned(cpu_to_be64(ep->l0), &dp->l0);
		put_unaligned(cpu_to_be64(ep->l1), &dp->l1);
		dp++;
		copied++;
	}
	ASSERT(copied != 0);
	xfs_validate_extents(ifp, copied, XFS_EXTFMT_INODE(ip));

	return (copied * (uint)sizeof(xfs_bmbt_rec_t));
}

/*
 * Each of the following cases stores data into the same region
 * of the on-disk inode, so only one of them can be valid at
 * any given time. While it is possible to have conflicting formats
 * and log flags, e.g. having XFS_ILOG_?DATA set when the fork is
 * in EXTENTS format, this can only happen when the fork has
 * changed formats after being modified but before being flushed.
 * In these cases, the format always takes precedence, because the
 * format indicates the current state of the fork.
 * 
 * Note: this requires user-space public scope for libxfs_iread
 */
/*ARGSUSED*/
void
xfs_iflush_fork(
	xfs_inode_t		*ip,
	xfs_dinode_t		*dip,
	xfs_inode_log_item_t	*iip,
	int			whichfork,
	xfs_buf_t		*bp)
{
	char			*cp;
	xfs_ifork_t		*ifp;
	xfs_mount_t		*mp;
#ifdef XFS_TRANS_DEBUG
	int			first;
#endif
	static const short	brootflag[2] =
		{ XFS_ILOG_DBROOT, XFS_ILOG_ABROOT };
	static const short	dataflag[2] =
		{ XFS_ILOG_DDATA, XFS_ILOG_ADATA };
	static const short	extflag[2] =
		{ XFS_ILOG_DEXT, XFS_ILOG_AEXT };

	if (!iip)
		return;
	ifp = XFS_IFORK_PTR(ip, whichfork);
	/*
	 * This can happen if we gave up in iformat in an error path,
	 * for the attribute fork.
	 */
	if (!ifp) {
		ASSERT(whichfork == XFS_ATTR_FORK);
		return;
	}
	cp = XFS_DFORK_PTR(dip, whichfork);
	mp = ip->i_mount;
	switch (XFS_IFORK_FORMAT(ip, whichfork)) {
	case XFS_DINODE_FMT_LOCAL:
		if ((iip->ili_format.ilf_fields & dataflag[whichfork]) &&
		    (ifp->if_bytes > 0)) {
			ASSERT(ifp->if_u1.if_data != NULL);
			ASSERT(ifp->if_bytes <= XFS_IFORK_SIZE(ip, whichfork));
			memcpy(cp, ifp->if_u1.if_data, ifp->if_bytes);
		}
		break;

	case XFS_DINODE_FMT_EXTENTS:
		ASSERT((ifp->if_flags & XFS_IFEXTENTS) ||
		       !(iip->ili_format.ilf_fields & extflag[whichfork]));
		ASSERT((xfs_iext_get_ext(ifp, 0) != NULL) ||
			(ifp->if_bytes == 0));
		ASSERT((xfs_iext_get_ext(ifp, 0) == NULL) ||
			(ifp->if_bytes > 0));
		if ((iip->ili_format.ilf_fields & extflag[whichfork]) &&
		    (ifp->if_bytes > 0)) {
			ASSERT(XFS_IFORK_NEXTENTS(ip, whichfork) > 0);
			(void)xfs_iextents_copy(ip, (xfs_bmbt_rec_t *)cp,
				whichfork);
		}
		break;

	case XFS_DINODE_FMT_BTREE:
		if ((iip->ili_format.ilf_fields & brootflag[whichfork]) &&
		    (ifp->if_broot_bytes > 0)) {
			ASSERT(ifp->if_broot != NULL);
			ASSERT(ifp->if_broot_bytes <=
			       (XFS_IFORK_SIZE(ip, whichfork) +
				XFS_BROOT_SIZE_ADJ));
			xfs_bmbt_to_bmdr(mp, ifp->if_broot, ifp->if_broot_bytes,
				(xfs_bmdr_block_t *)cp,
				XFS_DFORK_SIZE(dip, mp, whichfork));
		}
		break;

	case XFS_DINODE_FMT_DEV:
		if (iip->ili_format.ilf_fields & XFS_ILOG_DEV) {
			ASSERT(whichfork == XFS_DATA_FORK);
			dip->di_u.di_dev = cpu_to_be32(ip->i_df.if_u2.if_rdev);
		}
		break;

	case XFS_DINODE_FMT_UUID:
		if (iip->ili_format.ilf_fields & XFS_ILOG_UUID) {
			ASSERT(whichfork == XFS_DATA_FORK);
			memcpy(&dip->di_u.di_muuid, &ip->i_df.if_u2.if_uuid,
				sizeof(uuid_t));
		}
		break;

	default:
		ASSERT(0);
		break;
	}
}

/*
 * Return a pointer to the extent record at file index idx.
 */
xfs_bmbt_rec_host_t *
xfs_iext_get_ext(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	idx)		/* index of target extent */
{
	ASSERT(idx >= 0);
	if ((ifp->if_flags & XFS_IFEXTIREC) && (idx == 0)) {
		return ifp->if_u1.if_ext_irec->er_extbuf;
	} else if (ifp->if_flags & XFS_IFEXTIREC) {
		xfs_ext_irec_t	*erp;		/* irec pointer */
		int		erp_idx = 0;	/* irec index */
		xfs_extnum_t	page_idx = idx;	/* ext index in target list */

		erp = xfs_iext_idx_to_irec(ifp, &page_idx, &erp_idx, 0);
		return &erp->er_extbuf[page_idx];
	} else if (ifp->if_bytes) {
		return &ifp->if_u1.if_extents[idx];
	} else {
		return NULL;
	}
}

/*
 * Insert new item(s) into the extent records for incore inode
 * fork 'ifp'.  'count' new items are inserted at index 'idx'.
 */
void
xfs_iext_insert(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	idx,		/* starting index of new items */
	xfs_extnum_t	count,		/* number of inserted items */
	xfs_bmbt_irec_t	*new)		/* items to insert */
{
	xfs_extnum_t	i;		/* extent record index */

	ASSERT(ifp->if_flags & XFS_IFEXTENTS);
	xfs_iext_add(ifp, idx, count);
	for (i = idx; i < idx + count; i++, new++)
		xfs_bmbt_set_all(xfs_iext_get_ext(ifp, i), new);
}

/*
 * This is called when the amount of space required for incore file
 * extents needs to be increased. The ext_diff parameter stores the
 * number of new extents being added and the idx parameter contains
 * the extent index where the new extents will be added. If the new
 * extents are being appended, then we just need to (re)allocate and
 * initialize the space. Otherwise, if the new extents are being
 * inserted into the middle of the existing entries, a bit more work
 * is required to make room for the new extents to be inserted. The
 * caller is responsible for filling in the new extent entries upon
 * return.
 */
void
xfs_iext_add(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	idx,		/* index to begin adding exts */
	int		ext_diff)	/* number of extents to add */
{
	int		byte_diff;	/* new bytes being added */
	int		new_size;	/* size of extents after adding */
	xfs_extnum_t	nextents;	/* number of extents in file */

	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	ASSERT((idx >= 0) && (idx <= nextents));
	byte_diff = ext_diff * sizeof(xfs_bmbt_rec_t);
	new_size = ifp->if_bytes + byte_diff;
	/*
	 * If the new number of extents (nextents + ext_diff)
	 * fits inside the inode, then continue to use the inline
	 * extent buffer.
	 */
	if (nextents + ext_diff <= XFS_INLINE_EXTS) {
		if (idx < nextents) {
			memmove(&ifp->if_u2.if_inline_ext[idx + ext_diff],
				&ifp->if_u2.if_inline_ext[idx],
				(nextents - idx) * sizeof(xfs_bmbt_rec_t));
			memset(&ifp->if_u2.if_inline_ext[idx], 0, byte_diff);
		}
		ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
		ifp->if_real_bytes = 0;
		ifp->if_lastex = nextents + ext_diff;
	}
	/*
	 * Otherwise use a linear (direct) extent list.
	 * If the extents are currently inside the inode,
	 * xfs_iext_realloc_direct will switch us from
	 * inline to direct extent allocation mode.
	 */
	else if (nextents + ext_diff <= XFS_LINEAR_EXTS) {
		xfs_iext_realloc_direct(ifp, new_size);
		if (idx < nextents) {
			memmove(&ifp->if_u1.if_extents[idx + ext_diff],
				&ifp->if_u1.if_extents[idx],
				(nextents - idx) * sizeof(xfs_bmbt_rec_t));
			memset(&ifp->if_u1.if_extents[idx], 0, byte_diff);
		}
	}
	/* Indirection array */
	else {
		xfs_ext_irec_t	*erp;
		int		erp_idx = 0;
		int		page_idx = idx;

		ASSERT(nextents + ext_diff > XFS_LINEAR_EXTS);
		if (ifp->if_flags & XFS_IFEXTIREC) {
			erp = xfs_iext_idx_to_irec(ifp, &page_idx, &erp_idx, 1);
		} else {
			xfs_iext_irec_init(ifp);
			ASSERT(ifp->if_flags & XFS_IFEXTIREC);
			erp = ifp->if_u1.if_ext_irec;
		}
		/* Extents fit in target extent page */
		if (erp && erp->er_extcount + ext_diff <= XFS_LINEAR_EXTS) {
			if (page_idx < erp->er_extcount) {
				memmove(&erp->er_extbuf[page_idx + ext_diff],
					&erp->er_extbuf[page_idx],
					(erp->er_extcount - page_idx) *
					sizeof(xfs_bmbt_rec_t));
				memset(&erp->er_extbuf[page_idx], 0, byte_diff);
			}
			erp->er_extcount += ext_diff;
			xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, ext_diff);
		}
		/* Insert a new extent page */
		else if (erp) {
			xfs_iext_add_indirect_multi(ifp,
				erp_idx, page_idx, ext_diff);
		}
		/*
		 * If extent(s) are being appended to the last page in
		 * the indirection array and the new extent(s) don't fit
		 * in the page, then erp is NULL and erp_idx is set to
		 * the next index needed in the indirection array.
		 */
		else {
			int	count = ext_diff;

			while (count) {
				erp = xfs_iext_irec_new(ifp, erp_idx);
				erp->er_extcount = count;
				count -= MIN(count, (int)XFS_LINEAR_EXTS);
				if (count) {
					erp_idx++;
				}
			}
		}
	}
	ifp->if_bytes = new_size;
}

/*
 * This is called when incore extents are being added to the indirection
 * array and the new extents do not fit in the target extent list. The
 * erp_idx parameter contains the irec index for the target extent list
 * in the indirection array, and the idx parameter contains the extent
 * index within the list. The number of extents being added is stored
 * in the count parameter.
 *
 *    |-------|   |-------|
 *    |       |   |       |    idx - number of extents before idx
 *    |  idx  |   | count |
 *    |       |   |       |    count - number of extents being inserted at idx
 *    |-------|   |-------|
 *    | count |   | nex2  |    nex2 - number of extents after idx + count
 *    |-------|   |-------|
 */
void
xfs_iext_add_indirect_multi(
	xfs_ifork_t	*ifp,			/* inode fork pointer */
	int		erp_idx,		/* target extent irec index */
	xfs_extnum_t	idx,			/* index within target list */
	int		count)			/* new extents being added */
{
	int		byte_diff;		/* new bytes being added */
	xfs_ext_irec_t	*erp;			/* pointer to irec entry */
	xfs_extnum_t	ext_diff;		/* number of extents to add */
	xfs_extnum_t	ext_cnt;		/* new extents still needed */
	xfs_extnum_t	nex2;			/* extents after idx + count */
	xfs_bmbt_rec_t	*nex2_ep = NULL;	/* temp list for nex2 extents */
	int		nlists;			/* number of irec's (lists) */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	erp = &ifp->if_u1.if_ext_irec[erp_idx];
	nex2 = erp->er_extcount - idx;
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;

	/*
	 * Save second part of target extent list
	 * (all extents past */
	if (nex2) {
		byte_diff = nex2 * sizeof(xfs_bmbt_rec_t);
		nex2_ep = (xfs_bmbt_rec_t *) kmem_alloc(byte_diff, KM_NOFS);
		memmove(nex2_ep, &erp->er_extbuf[idx], byte_diff);
		erp->er_extcount -= nex2;
		xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, -nex2);
		memset(&erp->er_extbuf[idx], 0, byte_diff);
	}

	/*
	 * Add the new extents to the end of the target
	 * list, then allocate new irec record(s) and
	 * extent buffer(s) as needed to store the rest
	 * of the new extents.
	 */
	ext_cnt = count;
	ext_diff = MIN(ext_cnt, (int)XFS_LINEAR_EXTS - erp->er_extcount);
	if (ext_diff) {
		erp->er_extcount += ext_diff;
		xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, ext_diff);
		ext_cnt -= ext_diff;
	}
	while (ext_cnt) {
		erp_idx++;
		erp = xfs_iext_irec_new(ifp, erp_idx);
		ext_diff = MIN(ext_cnt, (int)XFS_LINEAR_EXTS);
		erp->er_extcount = ext_diff;
		xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, ext_diff);
		ext_cnt -= ext_diff;
	}

	/* Add nex2 extents back to indirection array */
	if (nex2) {
		xfs_extnum_t	ext_avail;
		int		i;

		byte_diff = nex2 * sizeof(xfs_bmbt_rec_t);
		ext_avail = XFS_LINEAR_EXTS - erp->er_extcount;
		i = 0;
		/*
		 * If nex2 extents fit in the current page, append
		 * nex2_ep after the new extents.
		 */
		if (nex2 <= ext_avail) {
			i = erp->er_extcount;
		}
		/*
		 * Otherwise, check if space is available in the
		 * next page.
		 */
		else if ((erp_idx < nlists - 1) &&
			 (nex2 <= (ext_avail = XFS_LINEAR_EXTS -
			  ifp->if_u1.if_ext_irec[erp_idx+1].er_extcount))) {
			erp_idx++;
			erp++;
			/* Create a hole for nex2 extents */
			memmove(&erp->er_extbuf[nex2], erp->er_extbuf,
				erp->er_extcount * sizeof(xfs_bmbt_rec_t));
		}
		/*
		 * Final choice, create a new extent page for
		 * nex2 extents.
		 */
		else {
			erp_idx++;
			erp = xfs_iext_irec_new(ifp, erp_idx);
		}
		memmove(&erp->er_extbuf[i], nex2_ep, byte_diff);
		kmem_free(nex2_ep);
		erp->er_extcount += nex2;
		xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, nex2);
	}
}

/*
 * This is called when the amount of space required for incore file
 * extents needs to be decreased. The ext_diff parameter stores the
 * number of extents to be removed and the idx parameter contains
 * the extent index where the extents will be removed from.
 *
 * If the amount of space needed has decreased below the linear
 * limit, XFS_IEXT_BUFSZ, then switch to using the contiguous
 * extent array.  Otherwise, use kmem_realloc() to adjust the
 * size to what is needed.
 */
void
xfs_iext_remove(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	idx,		/* index to begin removing exts */
	int		ext_diff)	/* number of extents to remove */
{
	xfs_extnum_t	nextents;	/* number of extents in file */
	int		new_size;	/* size of extents after removal */

	ASSERT(ext_diff > 0);
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	new_size = (nextents - ext_diff) * sizeof(xfs_bmbt_rec_t);

	if (new_size == 0) {
		xfs_iext_destroy(ifp);
	} else if (ifp->if_flags & XFS_IFEXTIREC) {
		xfs_iext_remove_indirect(ifp, idx, ext_diff);
	} else if (ifp->if_real_bytes) {
		xfs_iext_remove_direct(ifp, idx, ext_diff);
	} else {
		xfs_iext_remove_inline(ifp, idx, ext_diff);
	}
	ifp->if_bytes = new_size;
}

/*
 * This removes ext_diff extents from the inline buffer, beginning
 * at extent index idx.
 */
void
xfs_iext_remove_inline(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	idx,		/* index to begin removing exts */
	int		ext_diff)	/* number of extents to remove */
{
	int		nextents;	/* number of extents in file */

	ASSERT(!(ifp->if_flags & XFS_IFEXTIREC));
	ASSERT(idx < XFS_INLINE_EXTS);
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	ASSERT(((nextents - ext_diff) > 0) &&
		(nextents - ext_diff) < XFS_INLINE_EXTS);

	if (idx + ext_diff < nextents) {
		memmove(&ifp->if_u2.if_inline_ext[idx],
			&ifp->if_u2.if_inline_ext[idx + ext_diff],
			(nextents - (idx + ext_diff)) *
			 sizeof(xfs_bmbt_rec_t));
		memset(&ifp->if_u2.if_inline_ext[nextents - ext_diff],
			0, ext_diff * sizeof(xfs_bmbt_rec_t));
	} else {
		memset(&ifp->if_u2.if_inline_ext[idx], 0,
			ext_diff * sizeof(xfs_bmbt_rec_t));
	}
}

/*
 * This removes ext_diff extents from a linear (direct) extent list,
 * beginning at extent index idx. If the extents are being removed
 * from the end of the list (ie. truncate) then we just need to re-
 * allocate the list to remove the extra space. Otherwise, if the
 * extents are being removed from the middle of the existing extent
 * entries, then we first need to move the extent records beginning
 * at idx + ext_diff up in the list to overwrite the records being
 * removed, then remove the extra space via kmem_realloc.
 */
void
xfs_iext_remove_direct(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	idx,		/* index to begin removing exts */
	int		ext_diff)	/* number of extents to remove */
{
	xfs_extnum_t	nextents;	/* number of extents in file */
	int		new_size;	/* size of extents after removal */

	ASSERT(!(ifp->if_flags & XFS_IFEXTIREC));
	new_size = ifp->if_bytes -
		(ext_diff * sizeof(xfs_bmbt_rec_t));
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);

	if (new_size == 0) {
		xfs_iext_destroy(ifp);
		return;
	}
	/* Move extents up in the list (if needed) */
	if (idx + ext_diff < nextents) {
		memmove(&ifp->if_u1.if_extents[idx],
			&ifp->if_u1.if_extents[idx + ext_diff],
			(nextents - (idx + ext_diff)) *
			 sizeof(xfs_bmbt_rec_t));
	}
	memset(&ifp->if_u1.if_extents[nextents - ext_diff],
		0, ext_diff * sizeof(xfs_bmbt_rec_t));
	/*
	 * Reallocate the direct extent list. If the extents
	 * will fit inside the inode then xfs_iext_realloc_direct
	 * will switch from direct to inline extent allocation
	 * mode for us.
	 */
	xfs_iext_realloc_direct(ifp, new_size);
	ifp->if_bytes = new_size;
}

/*
 * This is called when incore extents are being removed from the
 * indirection array and the extents being removed span multiple extent
 * buffers. The idx parameter contains the file extent index where we
 * want to begin removing extents, and the count parameter contains
 * how many extents need to be removed.
 *
 *    |-------|   |-------|
 *    | nex1  |   |       |    nex1 - number of extents before idx
 *    |-------|   | count |
 *    |       |   |       |    count - number of extents being removed at idx
 *    | count |   |-------|
 *    |       |   | nex2  |    nex2 - number of extents after idx + count
 *    |-------|   |-------|
 */
void
xfs_iext_remove_indirect(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	idx,		/* index to begin removing extents */
	int		count)		/* number of extents to remove */
{
	xfs_ext_irec_t	*erp;		/* indirection array pointer */
	int		erp_idx = 0;	/* indirection array index */
	xfs_extnum_t	ext_cnt;	/* extents left to remove */
	xfs_extnum_t	ext_diff;	/* extents to remove in current list */
	xfs_extnum_t	nex1;		/* number of extents before idx */
	xfs_extnum_t	nex2;		/* extents after idx + count */
	int		nlists;		/* entries in indirection array */
	int		page_idx = idx;	/* index in target extent list */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	erp = xfs_iext_idx_to_irec(ifp,  &page_idx, &erp_idx, 0);
	ASSERT(erp != NULL);
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
	nex1 = page_idx;
	ext_cnt = count;
	while (ext_cnt) {
		nex2 = MAX((erp->er_extcount - (nex1 + ext_cnt)), 0);
		ext_diff = MIN(ext_cnt, (erp->er_extcount - nex1));
		/*
		 * Check for deletion of entire list;
		 * xfs_iext_irec_remove() updates extent offsets.
		 */
		if (ext_diff == erp->er_extcount) {
			xfs_iext_irec_remove(ifp, erp_idx);
			ext_cnt -= ext_diff;
			nex1 = 0;
			if (ext_cnt) {
				ASSERT(erp_idx < ifp->if_real_bytes /
					XFS_IEXT_BUFSZ);
				erp = &ifp->if_u1.if_ext_irec[erp_idx];
				nex1 = 0;
				continue;
			} else {
				break;
			}
		}
		/* Move extents up (if needed) */
		if (nex2) {
			memmove(&erp->er_extbuf[nex1],
				&erp->er_extbuf[nex1 + ext_diff],
				nex2 * sizeof(xfs_bmbt_rec_t));
		}
		/* Zero out rest of page */
		memset(&erp->er_extbuf[nex1 + nex2], 0, (XFS_IEXT_BUFSZ -
			((nex1 + nex2) * sizeof(xfs_bmbt_rec_t))));
		/* Update remaining counters */
		erp->er_extcount -= ext_diff;
		xfs_iext_irec_update_extoffs(ifp, erp_idx + 1, -ext_diff);
		ext_cnt -= ext_diff;
		nex1 = 0;
		erp_idx++;
		erp++;
	}
	ifp->if_bytes -= count * sizeof(xfs_bmbt_rec_t);
	xfs_iext_irec_compact(ifp);
}

/*
 * Create, destroy, or resize a linear (direct) block of extents.
 */
void
xfs_iext_realloc_direct(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	int		new_size)	/* new size of extents */
{
	int		rnew_size;	/* real new size of extents */

	rnew_size = new_size;

	ASSERT(!(ifp->if_flags & XFS_IFEXTIREC) ||
		((new_size >= 0) && (new_size <= XFS_IEXT_BUFSZ) &&
		 (new_size != ifp->if_real_bytes)));

	/* Free extent records */
	if (new_size == 0) {
		xfs_iext_destroy(ifp);
	}
	/* Resize direct extent list and zero any new bytes */
	else if (ifp->if_real_bytes) {
		/* Check if extents will fit inside the inode */
		if (new_size <= XFS_INLINE_EXTS * sizeof(xfs_bmbt_rec_t)) {
			xfs_iext_direct_to_inline(ifp, new_size /
				(uint)sizeof(xfs_bmbt_rec_t));
			ifp->if_bytes = new_size;
			return;
		}
		if (!is_power_of_2(new_size)){
			rnew_size = roundup_pow_of_two(new_size);
		}
		if (rnew_size != ifp->if_real_bytes) {
			ifp->if_u1.if_extents =
				kmem_realloc(ifp->if_u1.if_extents,
						rnew_size,
						ifp->if_real_bytes, KM_NOFS);
		}
		if (rnew_size > ifp->if_real_bytes) {
			memset(&ifp->if_u1.if_extents[ifp->if_bytes /
				(uint)sizeof(xfs_bmbt_rec_t)], 0,
				rnew_size - ifp->if_real_bytes);
		}
	}
	/*
	 * Switch from the inline extent buffer to a direct
	 * extent list. Be sure to include the inline extent
	 * bytes in new_size.
	 */
	else {
		new_size += ifp->if_bytes;
		if (!is_power_of_2(new_size)) {
			rnew_size = roundup_pow_of_two(new_size);
		}
		xfs_iext_inline_to_direct(ifp, rnew_size);
	}
	ifp->if_real_bytes = rnew_size;
	ifp->if_bytes = new_size;
}

/*
 * Switch from linear (direct) extent records to inline buffer.
 */
void
xfs_iext_direct_to_inline(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	nextents)	/* number of extents in file */
{
	ASSERT(ifp->if_flags & XFS_IFEXTENTS);
	ASSERT(nextents <= XFS_INLINE_EXTS);
	/*
	 * The inline buffer was zeroed when we switched
	 * from inline to direct extent allocation mode,
	 * so we don't need to clear it here.
	 */
	memcpy(ifp->if_u2.if_inline_ext, ifp->if_u1.if_extents,
		nextents * sizeof(xfs_bmbt_rec_t));
	kmem_free(ifp->if_u1.if_extents);
	ifp->if_u1.if_extents = ifp->if_u2.if_inline_ext;
	ifp->if_real_bytes = 0;
}

/*
 * Switch from inline buffer to linear (direct) extent records.
 * new_size should already be rounded up to the next power of 2
 * by the caller (when appropriate), so use new_size as it is.
 * However, since new_size may be rounded up, we can't update
 * if_bytes here. It is the caller's responsibility to update
 * if_bytes upon return.
 */
void
xfs_iext_inline_to_direct(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	int		new_size)	/* number of extents in file */
{
	ifp->if_u1.if_extents = kmem_alloc(new_size, KM_NOFS);
	memset(ifp->if_u1.if_extents, 0, new_size);
	if (ifp->if_bytes) {
		memcpy(ifp->if_u1.if_extents, ifp->if_u2.if_inline_ext,
			ifp->if_bytes);
		memset(ifp->if_u2.if_inline_ext, 0, XFS_INLINE_EXTS *
			sizeof(xfs_bmbt_rec_t));
	}
	ifp->if_real_bytes = new_size;
}

/*
 * Resize an extent indirection array to new_size bytes.
 */
void
xfs_iext_realloc_indirect(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	int		new_size)	/* new indirection array size */
{
	int		nlists;		/* number of irec's (ex lists) */
	int		size;		/* current indirection array size */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
	size = nlists * sizeof(xfs_ext_irec_t);
	ASSERT(ifp->if_real_bytes);
	ASSERT((new_size >= 0) && (new_size != size));
	if (new_size == 0) {
		xfs_iext_destroy(ifp);
	} else {
		ifp->if_u1.if_ext_irec = (xfs_ext_irec_t *)
			kmem_realloc(ifp->if_u1.if_ext_irec,
				new_size, size, KM_NOFS);
	}
}

/*
 * Switch from indirection array to linear (direct) extent allocations.
 */
void
xfs_iext_indirect_to_direct(
	 xfs_ifork_t	*ifp)		/* inode fork pointer */
{
	xfs_bmbt_rec_host_t *ep;	/* extent record pointer */
	xfs_extnum_t	nextents;	/* number of extents in file */
	int		size;		/* size of file extents */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	ASSERT(nextents <= XFS_LINEAR_EXTS);
	size = nextents * sizeof(xfs_bmbt_rec_t);

	xfs_iext_irec_compact_pages(ifp);
	ASSERT(ifp->if_real_bytes == XFS_IEXT_BUFSZ);

	ep = ifp->if_u1.if_ext_irec->er_extbuf;
	kmem_free(ifp->if_u1.if_ext_irec);
	ifp->if_flags &= ~XFS_IFEXTIREC;
	ifp->if_u1.if_extents = ep;
	ifp->if_bytes = size;
	if (nextents < XFS_LINEAR_EXTS) {
		xfs_iext_realloc_direct(ifp, size);
	}
}

/*
 * Free incore file extents.
 */
void
xfs_iext_destroy(
	xfs_ifork_t	*ifp)		/* inode fork pointer */
{
	if (ifp->if_flags & XFS_IFEXTIREC) {
		int	erp_idx;
		int	nlists;

		nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
		for (erp_idx = nlists - 1; erp_idx >= 0 ; erp_idx--) {
			xfs_iext_irec_remove(ifp, erp_idx);
		}
		ifp->if_flags &= ~XFS_IFEXTIREC;
	} else if (ifp->if_real_bytes) {
		kmem_free(ifp->if_u1.if_extents);
	} else if (ifp->if_bytes) {
		memset(ifp->if_u2.if_inline_ext, 0, XFS_INLINE_EXTS *
			sizeof(xfs_bmbt_rec_t));
	}
	ifp->if_u1.if_extents = NULL;
	ifp->if_real_bytes = 0;
	ifp->if_bytes = 0;
}

/*
 * Return a pointer to the extent record for file system block bno.
 */
xfs_bmbt_rec_host_t *			/* pointer to found extent record */
xfs_iext_bno_to_ext(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_fileoff_t	bno,		/* block number to search for */
	xfs_extnum_t	*idxp)		/* index of target extent */
{
	xfs_bmbt_rec_host_t *base;	/* pointer to first extent */
	xfs_filblks_t	blockcount = 0;	/* number of blocks in extent */
	xfs_bmbt_rec_host_t *ep = NULL;	/* pointer to target extent */
	xfs_ext_irec_t	*erp = NULL;	/* indirection array pointer */
	int		high;		/* upper boundary in search */
	xfs_extnum_t	idx = 0;	/* index of target extent */
	int		low;		/* lower boundary in search */
	xfs_extnum_t	nextents;	/* number of file extents */
	xfs_fileoff_t	startoff = 0;	/* start offset of extent */

	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	if (nextents == 0) {
		*idxp = 0;
		return NULL;
	}
	low = 0;
	if (ifp->if_flags & XFS_IFEXTIREC) {
		/* Find target extent list */
		int	erp_idx = 0;
		erp = xfs_iext_bno_to_irec(ifp, bno, &erp_idx);
		base = erp->er_extbuf;
		high = erp->er_extcount - 1;
	} else {
		base = ifp->if_u1.if_extents;
		high = nextents - 1;
	}
	/* Binary search extent records */
	while (low <= high) {
		idx = (low + high) >> 1;
		ep = base + idx;
		startoff = xfs_bmbt_get_startoff(ep);
		blockcount = xfs_bmbt_get_blockcount(ep);
		if (bno < startoff) {
			high = idx - 1;
		} else if (bno >= startoff + blockcount) {
			low = idx + 1;
		} else {
			/* Convert back to file-based extent index */
			if (ifp->if_flags & XFS_IFEXTIREC) {
				idx += erp->er_extoff;
			}
			*idxp = idx;
			return ep;
		}
	}
	/* Convert back to file-based extent index */
	if (ifp->if_flags & XFS_IFEXTIREC) {
		idx += erp->er_extoff;
	}
	if (bno >= startoff + blockcount) {
		if (++idx == nextents) {
			ep = NULL;
		} else {
			ep = xfs_iext_get_ext(ifp, idx);
		}
	}
	*idxp = idx;
	return ep;
}

/*
 * Return a pointer to the indirection array entry containing the
 * extent record for filesystem block bno. Store the index of the
 * target irec in *erp_idxp.
 */
xfs_ext_irec_t *			/* pointer to found extent record */
xfs_iext_bno_to_irec(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_fileoff_t	bno,		/* block number to search for */
	int		*erp_idxp)	/* irec index of target ext list */
{
	xfs_ext_irec_t	*erp = NULL;	/* indirection array pointer */
	xfs_ext_irec_t	*erp_next;	/* next indirection array entry */
	int		erp_idx;	/* indirection array index */
	int		nlists;		/* number of extent irec's (lists) */
	int		high;		/* binary search upper limit */
	int		low;		/* binary search lower limit */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
	erp_idx = 0;
	low = 0;
	high = nlists - 1;
	while (low <= high) {
		erp_idx = (low + high) >> 1;
		erp = &ifp->if_u1.if_ext_irec[erp_idx];
		erp_next = erp_idx < nlists - 1 ? erp + 1 : NULL;
		if (bno < xfs_bmbt_get_startoff(erp->er_extbuf)) {
			high = erp_idx - 1;
		} else if (erp_next && bno >=
			   xfs_bmbt_get_startoff(erp_next->er_extbuf)) {
			low = erp_idx + 1;
		} else {
			break;
		}
	}
	*erp_idxp = erp_idx;
	return erp;
}

/*
 * Return a pointer to the indirection array entry containing the
 * extent record at file extent index *idxp. Store the index of the
 * target irec in *erp_idxp and store the page index of the target
 * extent record in *idxp.
 */
xfs_ext_irec_t *
xfs_iext_idx_to_irec(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_extnum_t	*idxp,		/* extent index (file -> page) */
	int		*erp_idxp,	/* pointer to target irec */
	int		realloc)	/* new bytes were just added */
{
	xfs_ext_irec_t	*prev;		/* pointer to previous irec */
	xfs_ext_irec_t	*erp = NULL;	/* pointer to current irec */
	int		erp_idx;	/* indirection array index */
	int		nlists;		/* number of irec's (ex lists) */
	int		high;		/* binary search upper limit */
	int		low;		/* binary search lower limit */
	xfs_extnum_t	page_idx = *idxp; /* extent index in target list */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	ASSERT(page_idx >= 0 && page_idx <=
		ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t));
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
	erp_idx = 0;
	low = 0;
	high = nlists - 1;

	/* Binary search extent irec's */
	while (low <= high) {
		erp_idx = (low + high) >> 1;
		erp = &ifp->if_u1.if_ext_irec[erp_idx];
		prev = erp_idx > 0 ? erp - 1 : NULL;
		if (page_idx < erp->er_extoff || (page_idx == erp->er_extoff &&
		     realloc && prev && prev->er_extcount < XFS_LINEAR_EXTS)) {
			high = erp_idx - 1;
		} else if (page_idx > erp->er_extoff + erp->er_extcount ||
			   (page_idx == erp->er_extoff + erp->er_extcount &&
			    !realloc)) {
			low = erp_idx + 1;
		} else if (page_idx == erp->er_extoff + erp->er_extcount &&
			   erp->er_extcount == XFS_LINEAR_EXTS) {
			ASSERT(realloc);
			page_idx = 0;
			erp_idx++;
			erp = erp_idx < nlists ? erp + 1 : NULL;
			break;
		} else {
			page_idx -= erp->er_extoff;
			break;
		}
	}
	*idxp = page_idx;
	*erp_idxp = erp_idx;
	return(erp);
}

/*
 * Allocate and initialize an indirection array once the space needed
 * for incore extents increases above XFS_IEXT_BUFSZ.
 */
void
xfs_iext_irec_init(
	xfs_ifork_t	*ifp)		/* inode fork pointer */
{
	xfs_ext_irec_t	*erp;		/* indirection array pointer */
	xfs_extnum_t	nextents;	/* number of extents in file */

	ASSERT(!(ifp->if_flags & XFS_IFEXTIREC));
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	ASSERT(nextents <= XFS_LINEAR_EXTS);

	erp = kmem_alloc(sizeof(xfs_ext_irec_t), KM_NOFS);

	if (nextents == 0) {
		ifp->if_u1.if_extents = kmem_alloc(XFS_IEXT_BUFSZ, KM_NOFS);
	} else if (!ifp->if_real_bytes) {
		xfs_iext_inline_to_direct(ifp, XFS_IEXT_BUFSZ);
	} else if (ifp->if_real_bytes < XFS_IEXT_BUFSZ) {
		xfs_iext_realloc_direct(ifp, XFS_IEXT_BUFSZ);
	}
	erp->er_extbuf = ifp->if_u1.if_extents;
	erp->er_extcount = nextents;
	erp->er_extoff = 0;

	ifp->if_flags |= XFS_IFEXTIREC;
	ifp->if_real_bytes = XFS_IEXT_BUFSZ;
	ifp->if_bytes = nextents * sizeof(xfs_bmbt_rec_t);
	ifp->if_u1.if_ext_irec = erp;

	return;
}

/*
 * Allocate and initialize a new entry in the indirection array.
 */
xfs_ext_irec_t *
xfs_iext_irec_new(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	int		erp_idx)	/* index for new irec */
{
	xfs_ext_irec_t	*erp;		/* indirection array pointer */
	int		i;		/* loop counter */
	int		nlists;		/* number of irec's (ex lists) */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;

	/* Resize indirection array */
	xfs_iext_realloc_indirect(ifp, ++nlists *
				  sizeof(xfs_ext_irec_t));
	/*
	 * Move records down in the array so the
	 * new page can use erp_idx.
	 */
	erp = ifp->if_u1.if_ext_irec;
	for (i = nlists - 1; i > erp_idx; i--) {
		memmove(&erp[i], &erp[i-1], sizeof(xfs_ext_irec_t));
	}
	ASSERT(i == erp_idx);

	/* Initialize new extent record */
	erp = ifp->if_u1.if_ext_irec;
	erp[erp_idx].er_extbuf = kmem_alloc(XFS_IEXT_BUFSZ, KM_NOFS);
	ifp->if_real_bytes = nlists * XFS_IEXT_BUFSZ;
	memset(erp[erp_idx].er_extbuf, 0, XFS_IEXT_BUFSZ);
	erp[erp_idx].er_extcount = 0;
	erp[erp_idx].er_extoff = erp_idx > 0 ?
		erp[erp_idx-1].er_extoff + erp[erp_idx-1].er_extcount : 0;
	return (&erp[erp_idx]);
}

/*
 * Remove a record from the indirection array.
 */
void
xfs_iext_irec_remove(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	int		erp_idx)	/* irec index to remove */
{
	xfs_ext_irec_t	*erp;		/* indirection array pointer */
	int		i;		/* loop counter */
	int		nlists;		/* number of irec's (ex lists) */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
	erp = &ifp->if_u1.if_ext_irec[erp_idx];
	if (erp->er_extbuf) {
		xfs_iext_irec_update_extoffs(ifp, erp_idx + 1,
			-erp->er_extcount);
		kmem_free(erp->er_extbuf);
	}
	/* Compact extent records */
	erp = ifp->if_u1.if_ext_irec;
	for (i = erp_idx; i < nlists - 1; i++) {
		memmove(&erp[i], &erp[i+1], sizeof(xfs_ext_irec_t));
	}
	/*
	 * Manually free the last extent record from the indirection
	 * array.  A call to xfs_iext_realloc_indirect() with a size
	 * of zero would result in a call to xfs_iext_destroy() which
	 * would in turn call this function again, creating a nasty
	 * infinite loop.
	 */
	if (--nlists) {
		xfs_iext_realloc_indirect(ifp,
			nlists * sizeof(xfs_ext_irec_t));
	} else {
		kmem_free(ifp->if_u1.if_ext_irec);
	}
	ifp->if_real_bytes = nlists * XFS_IEXT_BUFSZ;
}

/*
 * This is called to clean up large amounts of unused memory allocated
 * by the indirection array.  Before compacting anything though, verify
 * that the indirection array is still needed and switch back to the
 * linear extent list (or even the inline buffer) if possible.  The
 * compaction policy is as follows:
 *
 *    Full Compaction: Extents fit into a single page (or inline buffer)
 * Partial Compaction: Extents occupy less than 50% of allocated space
 *      No Compaction: Extents occupy at least 50% of allocated space
 */
void
xfs_iext_irec_compact(
	xfs_ifork_t	*ifp)		/* inode fork pointer */
{
	xfs_extnum_t	nextents;	/* number of extents in file */
	int		nlists;		/* number of irec's (ex lists) */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);

	if (nextents == 0) {
		xfs_iext_destroy(ifp);
	} else if (nextents <= XFS_INLINE_EXTS) {
		xfs_iext_indirect_to_direct(ifp);
		xfs_iext_direct_to_inline(ifp, nextents);
	} else if (nextents <= XFS_LINEAR_EXTS) {
		xfs_iext_indirect_to_direct(ifp);
	} else if (nextents < (nlists * XFS_LINEAR_EXTS) >> 1) {
		xfs_iext_irec_compact_pages(ifp);
	}
}

/*
 * Combine extents from neighboring extent pages.
 */
void
xfs_iext_irec_compact_pages(
	xfs_ifork_t	*ifp)		/* inode fork pointer */
{
	xfs_ext_irec_t	*erp, *erp_next;/* pointers to irec entries */
	int		erp_idx = 0;	/* indirection array index */
	int		nlists;		/* number of irec's (ex lists) */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
	while (erp_idx < nlists - 1) {
		erp = &ifp->if_u1.if_ext_irec[erp_idx];
		erp_next = erp + 1;
		if (erp_next->er_extcount <=
		    (XFS_LINEAR_EXTS - erp->er_extcount)) {
			memcpy(&erp->er_extbuf[erp->er_extcount],
				erp_next->er_extbuf, erp_next->er_extcount *
				sizeof(xfs_bmbt_rec_t));
			erp->er_extcount += erp_next->er_extcount;
			/*
			 * Free page before removing extent record
			 * so er_extoffs don't get modified in
			 * xfs_iext_irec_remove.
			 */
			kmem_free(erp_next->er_extbuf);
			erp_next->er_extbuf = NULL;
			xfs_iext_irec_remove(ifp, erp_idx + 1);
			nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
		} else {
			erp_idx++;
		}
	}
}

/*
 * This is called to update the er_extoff field in the indirection
 * array when extents have been added or removed from one of the
 * extent lists. erp_idx contains the irec index to begin updating
 * at and ext_diff contains the number of extents that were added
 * or removed.
 */
void
xfs_iext_irec_update_extoffs(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	int		erp_idx,	/* irec index to update */
	int		ext_diff)	/* number of new extents */
{
	int		i;		/* loop counter */
	int		nlists;		/* number of irec's (ex lists */

	ASSERT(ifp->if_flags & XFS_IFEXTIREC);
	nlists = ifp->if_real_bytes / XFS_IEXT_BUFSZ;
	for (i = erp_idx; i < nlists; i++) {
		ifp->if_u1.if_ext_irec[i].er_extoff += ext_diff;
	}
}