text: /*
   * 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 <linux/log2.h>
  
  #include "xfs.h"
  #include "xfs_fs.h"
  #include "xfs_types.h"
  #include "xfs_bit.h"
  #include "xfs_log.h"
  #include "xfs_inum.h"
  #include "xfs_trans.h"
  #include "xfs_trans_priv.h"
  #include "xfs_sb.h"
  #include "xfs_ag.h"
  #include "xfs_dir2.h"
  #include "xfs_dmapi.h"
  #include "xfs_mount.h"
  #include "xfs_bmap_btree.h"
  #include "xfs_alloc_btree.h"
  #include "xfs_ialloc_btree.h"
  #include "xfs_dir2_sf.h"
  #include "xfs_attr_sf.h"
  #include "xfs_dinode.h"
  #include "xfs_inode.h"
  #include "xfs_buf_item.h"
  #include "xfs_inode_item.h"
  #include "xfs_btree.h"
  #include "xfs_btree_trace.h"
  #include "xfs_alloc.h"
  #include "xfs_ialloc.h"
  #include "xfs_bmap.h"
  #include "xfs_rw.h"
  #include "xfs_error.h"
  #include "xfs_utils.h"
  #include "xfs_quota.h"
  #include "xfs_filestream.h"
  #include "xfs_vnodeops.h"
  #include "xfs_trace.h"
  
  kmem_zone_t *xfs_ifork_zone;
  kmem_zone_t *xfs_inode_zone;
  
  /*
   * Used in xfs_itruncate().  This is the maximum number of extents
   * freed from a file in a single transaction.
   */
  #define	XFS_ITRUNC_MAX_EXTENTS	2
  
  STATIC int xfs_iflush_int(xfs_inode_t *, xfs_buf_t *);
  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,
  	struct xfs_imap	*imap,
  	xfs_buf_t	**bpp,
  	uint		buf_flags,
  	uint		iget_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 & XBF_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_magic) == XFS_DINODE_MAGIC &&
  			    XFS_DINODE_GOOD_VERSION(dip->di_version);
  		if (unlikely(XFS_TEST_ERROR(!di_ok, mp,
  						XFS_ERRTAG_ITOBP_INOTOBP,
  						XFS_RANDOM_ITOBP_INOTOBP))) {
  			if (iget_flags & XFS_IGET_UNTRUSTED) {
  				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_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 number within a file
   * system 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.
   *
   * Use xfs_imap() to determine the size and location of the
   * buffer to read from disk.
   */
  int
  xfs_inotobp(
  	xfs_mount_t	*mp,
  	xfs_trans_t	*tp,
  	xfs_ino_t	ino,
  	xfs_dinode_t	**dipp,
  	xfs_buf_t	**bpp,
  	int		*offset,
  	uint		imap_flags)
  {
  	struct xfs_imap	imap;
  	xfs_buf_t	*bp;
  	int		error;
  
  	imap.im_blkno = 0;
  	error = xfs_imap(mp, tp, ino, &imap, imap_flags);
  	if (error)
  		return error;
  
  	error = xfs_imap_to_bp(mp, tp, &imap, &bp, XBF_LOCK, imap_flags);
  	if (error)
  		return error;
  
  	*dipp = (xfs_dinode_t *)xfs_buf_offset(bp, imap.im_boffset);
  	*bpp = bp;
  	*offset = imap.im_boffset;
  	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.
   *
   * The inode is expected to already been mapped to its buffer and read
   * in once, thus we can 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_imap()).
   */
  int
  xfs_itobp(
  	xfs_mount_t	*mp,
  	xfs_trans_t	*tp,
  	xfs_inode_t	*ip,
  	xfs_dinode_t	**dipp,
  	xfs_buf_t	**bpp,
  	uint		buf_flags)
  {
  	xfs_buf_t	*bp;
  	int		error;
  
  	ASSERT(ip->i_imap.im_blkno != 0);
  
  	error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &bp, buf_flags, 0);
  	if (error)
  		return error;
  
  	if (!bp) {
  		ASSERT(buf_flags & XBF_TRYLOCK);
  		ASSERT(tp == NULL);
  		*bpp = NULL;
  		return EAGAIN;
  	}
  
  	*dipp = (xfs_dinode_t *)xfs_buf_offset(bp, ip->i_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()).
   */
  STATIC 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_nextents) +
  		     be16_to_cpu(dip->di_anextents) >
  		     be64_to_cpu(dip->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_nextents) +
  			      be16_to_cpu(dip->di_anextents)),
  			(unsigned long long)
  				be64_to_cpu(dip->di_nblocks));
  		XFS_CORRUPTION_ERROR("xfs_iformat(1)", XFS_ERRLEVEL_LOW,
  				     ip->i_mount, dip);
  		return XFS_ERROR(EFSCORRUPTED);
  	}
  
  	if (unlikely(dip->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_forkoff);
  		XFS_CORRUPTION_ERROR("xfs_iformat(2)", XFS_ERRLEVEL_LOW,
  				     ip->i_mount, dip);
  		return XFS_ERROR(EFSCORRUPTED);
  	}
  
  	if (unlikely((ip->i_d.di_flags & XFS_DIFLAG_REALTIME) &&
  		     !ip->i_mount->m_rtdev_targp)) {
  		xfs_fs_repair_cmn_err(CE_WARN, ip->i_mount,
  			"corrupt dinode %Lu, has realtime flag set.",
  			ip->i_ino);
  		XFS_CORRUPTION_ERROR("xfs_iformat(realtime)",
  				     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_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 = xfs_dinode_get_rdev(dip);
  		break;
  
  	case S_IFREG:
  	case S_IFLNK:
  	case S_IFDIR:
  		switch (dip->di_format) {
  		case XFS_DINODE_FMT_LOCAL:
  			/*
  			 * no local regular files yet
  			 */
  			if (unlikely((be16_to_cpu(dip->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_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_aformat) {
  	case XFS_DINODE_FMT_LOCAL:
  		atp = (xfs_attr_shortform_t *)XFS_DFORK_APTR(dip);
  		size = be16_to_cpu(atp->hdr.totsize);
  
  		if (unlikely(size < sizeof(struct xfs_attr_sf_hdr))) {
  			xfs_fs_repair_cmn_err(CE_WARN, ip->i_mount,
  				"corrupt inode %Lu "
  				"(bad attr fork size %Ld).",
  				(unsigned long long) ip->i_ino,
  				(long long) size);
  			XFS_CORRUPTION_ERROR("xfs_iformat(8)",
  					     XFS_ERRLEVEL_LOW,
  					     ip->i_mount, dip);
  			return XFS_ERROR(EFSCORRUPTED);
  		}
  
  		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;
  }
  
  STATIC void
  xfs_dinode_from_disk(
  	xfs_icdinode_t		*to,
  	xfs_dinode_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_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);
  }
  
  STATIC uint
  _xfs_dic2xflags(
  	__uint16_t		di_flags)
  {
  	uint			flags = 0;
  
  	if (di_flags & XFS_DIFLAG_ANY) {
  		if (di_flags & XFS_DIFLAG_REALTIME)
  			flags |= XFS_XFLAG_REALTIME;
  		if (di_flags & XFS_DIFLAG_PREALLOC)
  			flags |= XFS_XFLAG_PREALLOC;
  		if (di_flags & XFS_DIFLAG_IMMUTABLE)
  			flags |= XFS_XFLAG_IMMUTABLE;
  		if (di_flags & XFS_DIFLAG_APPEND)
  			flags |= XFS_XFLAG_APPEND;
  		if (di_flags & XFS_DIFLAG_SYNC)
  			flags |= XFS_XFLAG_SYNC;
  		if (di_flags & XFS_DIFLAG_NOATIME)
  			flags |= XFS_XFLAG_NOATIME;
  		if (di_flags & XFS_DIFLAG_NODUMP)
  			flags |= XFS_XFLAG_NODUMP;
  		if (di_flags & XFS_DIFLAG_RTINHERIT)
  			flags |= XFS_XFLAG_RTINHERIT;
  		if (di_flags & XFS_DIFLAG_PROJINHERIT)
  			flags |= XFS_XFLAG_PROJINHERIT;
  		if (di_flags & XFS_DIFLAG_NOSYMLINKS)
  			flags |= XFS_XFLAG_NOSYMLINKS;
  		if (di_flags & XFS_DIFLAG_EXTSIZE)
  			flags |= XFS_XFLAG_EXTSIZE;
  		if (di_flags & XFS_DIFLAG_EXTSZINHERIT)
  			flags |= XFS_XFLAG_EXTSZINHERIT;
  		if (di_flags & XFS_DIFLAG_NODEFRAG)
  			flags |= XFS_XFLAG_NODEFRAG;
  		if (di_flags & XFS_DIFLAG_FILESTREAM)
  			flags |= XFS_XFLAG_FILESTREAM;
  	}
  
  	return flags;
  }
  
  uint
  xfs_ip2xflags(
  	xfs_inode_t		*ip)
  {
  	xfs_icdinode_t		*dic = &ip->i_d;
  
  	return _xfs_dic2xflags(dic->di_flags) |
  				(XFS_IFORK_Q(ip) ? XFS_XFLAG_HASATTR : 0);
  }
  
  uint
  xfs_dic2xflags(
  	xfs_dinode_t		*dip)
  {
  	return _xfs_dic2xflags(be16_to_cpu(dip->di_flags)) |
  				(XFS_DFORK_Q(dip) ? XFS_XFLAG_HASATTR : 0);
  }
  
  /*
   * Read the disk inode attributes into the in-core inode structure.
   */
  int
  xfs_iread(
  	xfs_mount_t	*mp,
  	xfs_trans_t	*tp,
  	xfs_inode_t	*ip,
  	uint		iget_flags)
  {
  	xfs_buf_t	*bp;
  	xfs_dinode_t	*dip;
  	int		error;
  
  	/*
  	 * Fill in the location information in the in-core inode.
  	 */
  	error = xfs_imap(mp, tp, ip->i_ino, &ip->i_imap, iget_flags);
  	if (error)
  		return error;
  
  	/*
  	 * Get pointers to the on-disk inode and the buffer containing it.
  	 */
  	error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &bp,
  			       XBF_LOCK, iget_flags);
  	if (error)
  		return error;
  	dip = (xfs_dinode_t *)xfs_buf_offset(bp, ip->i_imap.im_boffset);
  
  	/*
  	 * If we got something that isn't an inode it means someone
  	 * (nfs or dmi) has a stale handle.
  	 */
  	if (be16_to_cpu(dip->di_magic) != XFS_DINODE_MAGIC) {
  #ifdef DEBUG
  		xfs_fs_cmn_err(CE_ALERT, mp, "xfs_iread: "
  				"dip->di_magic (0x%x) != "
  				"XFS_DINODE_MAGIC (0x%x)",
  				be16_to_cpu(dip->di_magic),
  				XFS_DINODE_MAGIC);
  #endif /* DEBUG */
  		error = XFS_ERROR(EINVAL);
  		goto out_brelse;
  	}
  
  	/*
  	 * If the on-disk inode is already linked to a directory
  	 * entry, copy all of the inode into the in-core inode.
  	 * xfs_iformat() handles copying in the inode format
  	 * specific information.
  	 * Otherwise, just get the truly permanent information.
  	 */
  	if (dip->di_mode) {
  		xfs_dinode_from_disk(&ip->i_d, dip);
  		error = xfs_iformat(ip, dip);
  		if (error)  {
  #ifdef DEBUG
  			xfs_fs_cmn_err(CE_ALERT, mp, "xfs_iread: "
  					"xfs_iformat() returned error %d",
  					error);
  #endif /* DEBUG */
  			goto out_brelse;
  		}
  	} else {
  		ip->i_d.di_magic = be16_to_cpu(dip->di_magic);
  		ip->i_d.di_version = dip->di_version;
  		ip->i_d.di_gen = be32_to_cpu(dip->di_gen);
  		ip->i_d.di_flushiter = be16_to_cpu(dip->di_flushiter);
  		/*
  		 * Make sure to pull in the mode here as well in
  		 * case the inode is released without being used.
  		 * This ensures that xfs_inactive() will see that
  		 * the inode is already free and not try to mess
  		 * with the uninitialized part of it.
  		 */
  		ip->i_d.di_mode = 0;
  		/*
  		 * Initialize the per-fork minima and maxima for a new
  		 * inode here.  xfs_iformat will do it for old inodes.
  		 */
  		ip->i_df.if_ext_max =
  			XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t);
  	}
  
  	/*
  	 * The inode format changed when we moved the link count and
  	 * made it 32 bits long.  If this is an old format inode,
  	 * convert it in memory to look like a new one.  If it gets
  	 * flushed to disk we will convert back before flushing or
  	 * logging it.  We zero out the new projid field and the old link
  	 * count field.  We'll handle clearing the pad field (the remains
  	 * of the old uuid field) when we actually convert the inode to
  	 * the new format. We don't change the version number so that we
  	 * can distinguish this from a real new format inode.
  	 */
  	if (ip->i_d.di_version == 1) {
  		ip->i_d.di_nlink = ip->i_d.di_onlink;
  		ip->i_d.di_onlink = 0;
  		ip->i_d.di_projid = 0;
  	}
  
  	ip->i_delayed_blks = 0;
  	ip->i_size = ip->i_d.di_size;
  
  	/*
  	 * Mark the buffer containing the inode as something to keep
  	 * around for a while.  This helps to keep recently accessed
  	 * meta-data in-core longer.
  	 */
  	XFS_BUF_SET_REF(bp, XFS_INO_REF);
  
  	/*
  	 * Use xfs_trans_brelse() to release the buffer containing the
  	 * on-disk inode, because it was acquired with xfs_trans_read_buf()
  	 * in xfs_itobp() above.  If tp is NULL, this is just a normal
  	 * brelse().  If we're within a transaction, then xfs_trans_brelse()
  	 * will only release the buffer if it is not dirty within the
  	 * transaction.  It will be OK to release the buffer in this case,
  	 * because inodes on disk are never destroyed and we will be
  	 * locking the new in-core inode before putting it in the hash
  	 * table where other processes can find it.  Thus we don't have
  	 * to worry about the inode being changed just because we released
  	 * the buffer.
  	 */
   out_brelse:
  	xfs_trans_brelse(tp, bp);
  	return error;
  }
  
  /*
   * 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;
  }
  
  /*
   * Allocate an inode on disk and return a copy of its in-core version.
   * The in-core inode is locked exclusively.  Set mode, nlink, and rdev
   * appropriately within the inode.  The uid and gid for the inode are
   * set according to the contents of the given cred structure.
   *
   * Use xfs_dialloc() to allocate the on-disk inode. If xfs_dialloc()
   * has a free inode available, call xfs_iget()
   * to obtain the in-core version of the allocated inode.  Finally,
   * fill in the inode and log its initial contents.  In this case,
   * ialloc_context would be set to NULL and call_again set to false.
   *
   * If xfs_dialloc() does not have an available inode,
   * it will replenish its supply by doing an allocation. Since we can
   * only do one allocation within a transaction without deadlocks, we
   * must commit the current transaction before returning the inode itself.
   * In this case, therefore, we will set call_again to true and return.
   * The caller should then commit the current transaction, start a new
   * transaction, and call xfs_ialloc() again to actually get the inode.
   *
   * To ensure that some other process does not grab the inode that
   * was allocated during the first call to xfs_ialloc(), this routine
   * also returns the [locked] bp pointing to the head of the freelist
   * as ialloc_context.  The caller should hold this buffer across
   * the commit and pass it back into this routine on the second call.
   *
   * If we are allocating quota inodes, we do not have a parent inode
   * to attach to or associate with (i.e. pip == NULL) because they
   * are not linked into the directory structure - they are attached
   * directly to the superblock - and so have no parent.
   */
  int
  xfs_ialloc(
  	xfs_trans_t	*tp,
  	xfs_inode_t	*pip,
  	mode_t		mode,
  	xfs_nlink_t	nlink,
  	xfs_dev_t	rdev,
  	cred_t		*cr,
  	xfs_prid_t	prid,
  	int		okalloc,
  	xfs_buf_t	**ialloc_context,
  	boolean_t	*call_again,
  	xfs_inode_t	**ipp)
  {
  	xfs_ino_t	ino;
  	xfs_inode_t	*ip;
  	uint		flags;
  	int		error;
  	timespec_t	tv;
  	int		filestreams = 0;
  
  	/*
  	 * Call the space management code to pick
  	 * the on-disk inode to be allocated.
  	 */
  	error = xfs_dialloc(tp, pip ? pip->i_ino : 0, mode, okalloc,
  			    ialloc_context, call_again, &ino);
  	if (error)
  		return error;
  	if (*call_again || ino == NULLFSINO) {
  		*ipp = NULL;
  		return 0;
  	}
  	ASSERT(*ialloc_context == NULL);
  
  	/*
  	 * Get the in-core inode with the lock held exclusively.
  	 * This is because we're setting fields here we need
  	 * to prevent others from looking at until we're done.
  	 */
  	error = xfs_trans_iget(tp->t_mountp, tp, ino,
  				XFS_IGET_CREATE, XFS_ILOCK_EXCL, &ip);
  	if (error)
  		return error;
  	ASSERT(ip != NULL);
  
  	ip->i_d.di_mode = (__uint16_t)mode;
  	ip->i_d.di_onlink = 0;
  	ip->i_d.di_nlink = nlink;
  	ASSERT(ip->i_d.di_nlink == nlink);
  	ip->i_d.di_uid = current_fsuid();
  	ip->i_d.di_gid = current_fsgid();
  	ip->i_d.di_projid = prid;
  	memset(&(ip->i_d.di_pad[0]), 0, sizeof(ip->i_d.di_pad));
  
  	/*
  	 * If the superblock version is up to where we support new format
  	 * inodes and this is currently an old format inode, then change
  	 * the inode version number now.  This way we only do the conversion
  	 * here rather than here and in the flush/logging code.
  	 */
  	if (xfs_sb_version_hasnlink(&tp->t_mountp->m_sb) &&
  	    ip->i_d.di_version == 1) {
  		ip->i_d.di_version = 2;
  		/*
  		 * We've already zeroed the old link count, the projid field,
  		 * and the pad field.
  		 */
  	}
  
  	/*
  	 * Project ids won't be stored on disk if we are using a version 1 inode.
  	 */
  	if ((prid != 0) && (ip->i_d.di_version == 1))
  		xfs_bump_ino_vers2(tp, ip);
  
  	if (pip && XFS_INHERIT_GID(pip)) {
  		ip->i_d.di_gid = pip->i_d.di_gid;
  		if ((pip->i_d.di_mode & S_ISGID) && (mode & S_IFMT) == S_IFDIR) {
  			ip->i_d.di_mode |= S_ISGID;
  		}
  	}
  
  	/*
  	 * If the group ID of the new file does not match the effective group
  	 * ID or one of the supplementary group IDs, the S_ISGID bit is cleared
  	 * (and only if the irix_sgid_inherit compatibility variable is set).
  	 */
  	if ((irix_sgid_inherit) &&
  	    (ip->i_d.di_mode & S_ISGID) &&
  	    (!in_group_p((gid_t)ip->i_d.di_gid))) {
  		ip->i_d.di_mode &= ~S_ISGID;
  	}
  
  	ip->i_d.di_size = 0;
  	ip->i_size = 0;
  	ip->i_d.di_nextents = 0;
  	ASSERT(ip->i_d.di_nblocks == 0);
  
  	nanotime(&tv);
  	ip->i_d.di_mtime.t_sec = (__int32_t)tv.tv_sec;
  	ip->i_d.di_mtime.t_nsec = (__int32_t)tv.tv_nsec;
  	ip->i_d.di_atime = ip->i_d.di_mtime;
  	ip->i_d.di_ctime = ip->i_d.di_mtime;
  
  	/*
  	 * di_gen will have been taken care of in xfs_iread.
  	 */
  	ip->i_d.di_extsize = 0;
  	ip->i_d.di_dmevmask = 0;
  	ip->i_d.di_dmstate = 0;
  	ip->i_d.di_flags = 0;
  	flags = XFS_ILOG_CORE;
  	switch (mode & S_IFMT) {
  	case S_IFIFO:
  	case S_IFCHR:
  	case S_IFBLK:
  	case S_IFSOCK:
  		ip->i_d.di_format = XFS_DINODE_FMT_DEV;
  		ip->i_df.if_u2.if_rdev = rdev;
  		ip->i_df.if_flags = 0;
  		flags |= XFS_ILOG_DEV;
  		break;
  	case S_IFREG:
  		/*
  		 * we can't set up filestreams until after the VFS inode
  		 * is set up properly.
  		 */
  		if (pip && xfs_inode_is_filestream(pip))
  			filestreams = 1;
  		/* fall through */
  	case S_IFDIR:
  		if (pip && (pip->i_d.di_flags & XFS_DIFLAG_ANY)) {
  			uint	di_flags = 0;
  
  			if ((mode & S_IFMT) == S_IFDIR) {
  				if (pip->i_d.di_flags & XFS_DIFLAG_RTINHERIT)
  					di_flags |= XFS_DIFLAG_RTINHERIT;
  				if (pip->i_d.di_flags & XFS_DIFLAG_EXTSZINHERIT) {
  					di_flags |= XFS_DIFLAG_EXTSZINHERIT;
  					ip->i_d.di_extsize = pip->i_d.di_extsize;
  				}
  			} else if ((mode & S_IFMT) == S_IFREG) {
  				if (pip->i_d.di_flags & XFS_DIFLAG_RTINHERIT)
  					di_flags |= XFS_DIFLAG_REALTIME;
  				if (pip->i_d.di_flags & XFS_DIFLAG_EXTSZINHERIT) {
  					di_flags |= XFS_DIFLAG_EXTSIZE;
  					ip->i_d.di_extsize = pip->i_d.di_extsize;
  				}
  			}
  			if ((pip->i_d.di_flags & XFS_DIFLAG_NOATIME) &&
  			    xfs_inherit_noatime)
  				di_flags |= XFS_DIFLAG_NOATIME;
  			if ((pip->i_d.di_flags & XFS_DIFLAG_NODUMP) &&
  			    xfs_inherit_nodump)
  				di_flags |= XFS_DIFLAG_NODUMP;
  			if ((pip->i_d.di_flags & XFS_DIFLAG_SYNC) &&
  			    xfs_inherit_sync)
  				di_flags |= XFS_DIFLAG_SYNC;
  			if ((pip->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) &&
  			    xfs_inherit_nosymlinks)
  				di_flags |= XFS_DIFLAG_NOSYMLINKS;
  			if (pip->i_d.di_flags & XFS_DIFLAG_PROJINHERIT)
  				di_flags |= XFS_DIFLAG_PROJINHERIT;
  			if ((pip->i_d.di_flags & XFS_DIFLAG_NODEFRAG) &&
  			    xfs_inherit_nodefrag)
  				di_flags |= XFS_DIFLAG_NODEFRAG;
  			if (pip->i_d.di_flags & XFS_DIFLAG_FILESTREAM)
  				di_flags |= XFS_DIFLAG_FILESTREAM;
  			ip->i_d.di_flags |= di_flags;
  		}
  		/* FALLTHROUGH */
  	case S_IFLNK:
  		ip->i_d.di_format = XFS_DINODE_FMT_EXTENTS;
  		ip->i_df.if_flags = XFS_IFEXTENTS;
  		ip->i_df.if_bytes = ip->i_df.if_real_bytes = 0;
  		ip->i_df.if_u1.if_extents = NULL;
  		break;
  	default:
  		ASSERT(0);
  	}
  	/*
  	 * Attribute fork settings for new inode.
  	 */
  	ip->i_d.di_aformat = XFS_DINODE_FMT_EXTENTS;
  	ip->i_d.di_anextents = 0;
  
  	/*
  	 * Log the new values stuffed into the inode.
  	 */
  	xfs_trans_log_inode(tp, ip, flags);
  
  	/* now that we have an i_mode we can setup inode ops and unlock */
  	xfs_setup_inode(ip);
  
  	/* now we have set up the vfs inode we can associate the filestream */
  	if (filestreams) {
  		error = xfs_filestream_associate(pip, ip);
  		if (error < 0)
  			return -error;
  		if (!error)
  			xfs_iflags_set(ip, XFS_IFILESTREAM);
  	}
  
  	*ipp = ip;
  	return 0;
  }
  
  /*
   * Check to make sure that there are no blocks allocated to the
   * file beyond the size of the file.  We don't check this for
   * files with fixed size extents or real time extents, but we
   * at least do it for regular files.
   */
  #ifdef DEBUG
  void
  xfs_isize_check(
  	xfs_mount_t	*mp,
  	xfs_inode_t	*ip,
  	xfs_fsize_t	isize)
  {
  	xfs_fileoff_t	map_first;
  	int		nimaps;
  	xfs_bmbt_irec_t	imaps[2];
  
  	if ((ip->i_d.di_mode & S_IFMT) != S_IFREG)
  		return;
  
  	if (XFS_IS_REALTIME_INODE(ip))
  		return;
  
  	if (ip->i_d.di_flags & XFS_DIFLAG_EXTSIZE)
  		return;
  
  	nimaps = 2;
  	map_first = XFS_B_TO_FSB(mp, (xfs_ufsize_t)isize);
  	/*
  	 * The filesystem could be shutting down, so bmapi may return
  	 * an error.
  	 */
  	if (xfs_bmapi(NULL, ip, map_first,
  			 (XFS_B_TO_FSB(mp,
  				       (xfs_ufsize_t)XFS_MAXIOFFSET(mp)) -
  			  map_first),
  			 XFS_BMAPI_ENTIRE, NULL, 0, imaps, &nimaps,
  			 NULL, NULL))
  	    return;
  	ASSERT(nimaps == 1);
  	ASSERT(imaps[0].br_startblock == HOLESTARTBLOCK);
  }
  #endif	/* DEBUG */
  
  /*
   * Calculate the last possible buffered byte in a file.  This must
   * include data that was buffered beyond the EOF by the write code.
   * This also needs to deal with overflowing the xfs_fsize_t type
   * which can happen for sizes near the limit.
   *
   * We also need to take into account any blocks beyond the EOF.  It
   * may be the case that they were buffered by a write which failed.
   * In that case the pages will still be in memory, but the inode size
   * will never have been updated.
   */
  STATIC xfs_fsize_t
  xfs_file_last_byte(
  	xfs_inode_t	*ip)
  {
  	xfs_mount_t	*mp;
  	xfs_fsize_t	last_byte;
  	xfs_fileoff_t	last_block;
  	xfs_fileoff_t	size_last_block;
  	int		error;
  
  	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL|XFS_IOLOCK_SHARED));
  
  	mp = ip->i_mount;
  	/*
  	 * Only check for blocks beyond the EOF if the extents have
  	 * been read in.  This eliminates the need for the inode lock,
  	 * and it also saves us from looking when it really isn't
  	 * necessary.
  	 */
  	if (ip->i_df.if_flags & XFS_IFEXTENTS) {
  		xfs_ilock(ip, XFS_ILOCK_SHARED);
  		error = xfs_bmap_last_offset(NULL, ip, &last_block,
  			XFS_DATA_FORK);
  		xfs_iunlock(ip, XFS_ILOCK_SHARED);
  		if (error) {
  			last_block = 0;
  		}
  	} else {
  		last_block = 0;
  	}
  	size_last_block = XFS_B_TO_FSB(mp, (xfs_ufsize_t)ip->i_size);
  	last_block = XFS_FILEOFF_MAX(last_block, size_last_block);
  
  	last_byte = XFS_FSB_TO_B(mp, last_block);
  	if (last_byte < 0) {
  		return XFS_MAXIOFFSET(mp);
  	}
  	last_byte += (1 << mp->m_writeio_log);
  	if (last_byte < 0) {
  		return XFS_MAXIOFFSET(mp);
  	}
  	return last_byte;
  }
  
  /*
   * Start the truncation of the file to new_size.  The new size
   * must be smaller than the current size.  This routine will
   * clear the buffer and page caches of file data in the removed
   * range, and xfs_itruncate_finish() will remove the underlying
   * disk blocks.
   *
   * The inode must have its I/O lock locked EXCLUSIVELY, and it
   * must NOT have the inode lock held at all.  This is because we're
   * calling into the buffer/page cache code and we can't hold the
   * inode lock when we do so.
   *
   * We need to wait for any direct I/Os in flight to complete before we
   * proceed with the truncate. This is needed to prevent the extents
   * being read or written by the direct I/Os from being removed while the
   * I/O is in flight as there is no other method of synchronising
   * direct I/O with the truncate operation.  Also, because we hold
   * the IOLOCK in exclusive mode, we prevent new direct I/Os from being
   * started until the truncate completes and drops the lock. Essentially,
   * the xfs_ioend_wait() call forms an I/O barrier that provides strict
   * ordering between direct I/Os and the truncate operation.
   *
   * The flags parameter can have either the value XFS_ITRUNC_DEFINITE
   * or XFS_ITRUNC_MAYBE.  The XFS_ITRUNC_MAYBE value should be used
   * in the case that the caller is locking things out of order and
   * may not be able to call xfs_itruncate_finish() with the inode lock
   * held without dropping the I/O lock.  If the caller must drop the
   * I/O lock before calling xfs_itruncate_finish(), then xfs_itruncate_start()
   * must be called again with all the same restrictions as the initial
   * call.
   */
  int
  xfs_itruncate_start(
  	xfs_inode_t	*ip,
  	uint		flags,
  	xfs_fsize_t	new_size)
  {
  	xfs_fsize_t	last_byte;
  	xfs_off_t	toss_start;
  	xfs_mount_t	*mp;
  	int		error = 0;
  
  	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
  	ASSERT((new_size == 0) || (new_size <= ip->i_size));
  	ASSERT((flags == XFS_ITRUNC_DEFINITE) ||
  	       (flags == XFS_ITRUNC_MAYBE));
  
  	mp = ip->i_mount;
  
  	/* wait for the completion of any pending DIOs */
  	if (new_size == 0 || new_size < ip->i_size)
  		xfs_ioend_wait(ip);
  
  	/*
  	 * Call toss_pages or flushinval_pages to get rid of pages
  	 * overlapping the region being removed.  We have to use
  	 * the less efficient flushinval_pages in the case that the
  	 * caller may not be able to finish the truncate without
  	 * dropping the inode's I/O lock.  Make sure
  	 * to catch any pages brought in by buffers overlapping
  	 * the EOF by searching out beyond the isize by our
  	 * block size. We round new_size up to a block boundary
  	 * so that we don't toss things on the same block as
  	 * new_size but before it.
  	 *
  	 * Before calling toss_page or flushinval_pages, make sure to
  	 * call remapf() over the same region if the file is mapped.
  	 * This frees up mapped file references to the pages in the
  	 * given range and for the flushinval_pages case it ensures
  	 * that we get the latest mapped changes flushed out.
  	 */
  	toss_start = XFS_B_TO_FSB(mp, (xfs_ufsize_t)new_size);
  	toss_start = XFS_FSB_TO_B(mp, toss_start);
  	if (toss_start < 0) {
  		/*
  		 * The place to start tossing is beyond our maximum
  		 * file size, so there is no way that the data extended
  		 * out there.
  		 */
  		return 0;
  	}
  	last_byte = xfs_file_last_byte(ip);
  	trace_xfs_itruncate_start(ip, flags, new_size, toss_start, last_byte);
  	if (last_byte > toss_start) {
  		if (flags & XFS_ITRUNC_DEFINITE) {
  			xfs_tosspages(ip, toss_start,
  					-1, FI_REMAPF_LOCKED);
  		} else {
  			error = xfs_flushinval_pages(ip, toss_start,
  					-1, FI_REMAPF_LOCKED);
  		}
  	}
  
  #ifdef DEBUG
  	if (new_size == 0) {
  		ASSERT(VN_CACHED(VFS_I(ip)) == 0);
  	}
  #endif
  	return error;
  }
  
  /*
   * Shrink the file to the given new_size.  The new size must be smaller than
   * the current size.  This will free up the underlying blocks in the removed
   * range after a call to xfs_itruncate_start() or xfs_atruncate_start().
   *
   * The transaction passed to this routine must have made a permanent log
   * reservation of at least XFS_ITRUNCATE_LOG_RES.  This routine may commit the
   * given transaction and start new ones, so make sure everything involved in
   * the transaction is tidy before calling here.  Some transaction will be
   * returned to the caller to be committed.  The incoming transaction must
   * already include the inode, and both inode locks must be held exclusively.
   * The inode must also be "held" within the transaction.  On return the inode
   * will be "held" within the returned transaction.  This routine does NOT
   * require any disk space to be reserved for it within the transaction.
   *
   * The fork parameter must be either xfs_attr_fork or xfs_data_fork, and it
   * indicates the fork which is to be truncated.  For the attribute fork we only
   * support truncation to size 0.
   *
   * We use the sync parameter to indicate whether or not the first transaction
   * we perform might have to be synchronous.  For the attr fork, it needs to be
   * so if the unlink of the inode is not yet known to be permanent in the log.
   * This keeps us from freeing and reusing the blocks of the attribute fork
   * before the unlink of the inode becomes permanent.
   *
   * For the data fork, we normally have to run synchronously if we're being
   * called out of the inactive path or we're being called out of the create path
   * where we're truncating an existing file.  Either way, the truncate needs to
   * be sync so blocks don't reappear in the file with altered data in case of a
   * crash.  wsync filesystems can run the first case async because anything that
   * shrinks the inode has to run sync so by the time we're called here from
   * inactive, the inode size is permanently set to 0.
   *
   * Calls from the truncate path always need to be sync unless we're in a wsync
   * filesystem and the file has already been unlinked.
   *
   * The caller is responsible for correctly setting the sync parameter.  It gets
   * too hard for us to guess here which path we're being called out of just
   * based on inode state.
   *
   * If we get an error, we must return with the inode locked and linked into the
   * current transaction. This keeps things simple for the higher level code,
   * because it always knows that the inode is locked and held in the transaction
   * that returns to it whether errors occur or not.  We don't mark the inode
   * dirty on error so that transactions can be easily aborted if possible.
   */
  int
  xfs_itruncate_finish(
  	xfs_trans_t	**tp,
  	xfs_inode_t	*ip,
  	xfs_fsize_t	new_size,
  	int		fork,
  	int		sync)
  {
  	xfs_fsblock_t	first_block;
  	xfs_fileoff_t	first_unmap_block;
  	xfs_fileoff_t	last_block;
  	xfs_filblks_t	unmap_len=0;
  	xfs_mount_t	*mp;
  	xfs_trans_t	*ntp;
  	int		done;
  	int		committed;
  	xfs_bmap_free_t	free_list;
  	int		error;
  
  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_IOLOCK_EXCL));
  	ASSERT((new_size == 0) || (new_size <= ip->i_size));
  	ASSERT(*tp != NULL);
  	ASSERT((*tp)->t_flags & XFS_TRANS_PERM_LOG_RES);
  	ASSERT(ip->i_transp == *tp);
  	ASSERT(ip->i_itemp != NULL);
  	ASSERT(ip->i_itemp->ili_flags & XFS_ILI_HOLD);
  
  
  	ntp = *tp;
  	mp = (ntp)->t_mountp;
  	ASSERT(! XFS_NOT_DQATTACHED(mp, ip));
  
  	/*
  	 * We only support truncating the entire attribute fork.
  	 */
  	if (fork == XFS_ATTR_FORK) {
  		new_size = 0LL;
  	}
  	first_unmap_block = XFS_B_TO_FSB(mp, (xfs_ufsize_t)new_size);
  	trace_xfs_itruncate_finish_start(ip, new_size);
  
  	/*
  	 * The first thing we do is set the size to new_size permanently
  	 * on disk.  This way we don't have to worry about anyone ever
  	 * being able to look at the data being freed even in the face
  	 * of a crash.  What we're getting around here is the case where
  	 * we free a block, it is allocated to another file, it is written
  	 * to, and then we crash.  If the new data gets written to the
  	 * file but the log buffers containing the free and reallocation
  	 * don't, then we'd end up with garbage in the blocks being freed.
  	 * As long as we make the new_size permanent before actually
  	 * freeing any blocks it doesn't matter if they get writtten to.
  	 *
  	 * The callers must signal into us whether or not the size
  	 * setting here must be synchronous.  There are a few cases
  	 * where it doesn't have to be synchronous.  Those cases
  	 * occur if the file is unlinked and we know the unlink is
  	 * permanent or if the blocks being truncated are guaranteed
  	 * to be beyond the inode eof (regardless of the link count)
  	 * and the eof value is permanent.  Both of these cases occur
  	 * only on wsync-mounted filesystems.  In those cases, we're
  	 * guaranteed that no user will ever see the data in the blocks
  	 * that are being truncated so the truncate can run async.
  	 * In the free beyond eof case, the file may wind up with
  	 * more blocks allocated to it than it needs if we crash
  	 * and that won't get fixed until the next time the file
  	 * is re-opened and closed but that's ok as that shouldn't
  	 * be too many blocks.
  	 *
  	 * However, we can't just make all wsync xactions run async
  	 * because there's one call out of the create path that needs
  	 * to run sync where it's truncating an existing file to size
  	 * 0 whose size is > 0.
  	 *
  	 * It's probably possible to come up with a test in this
  	 * routine that would correctly distinguish all the above
  	 * cases from the values of the function parameters and the
  	 * inode state but for sanity's sake, I've decided to let the
  	 * layers above just tell us.  It's simpler to correctly figure
  	 * out in the layer above exactly under what conditions we
  	 * can run async and I think it's easier for others read and
  	 * follow the logic in case something has to be changed.
  	 * cscope is your friend -- rcc.
  	 *
  	 * The attribute fork is much simpler.
  	 *
  	 * For the attribute fork we allow the caller to tell us whether
  	 * the unlink of the inode that led to this call is yet permanent
  	 * in the on disk log.  If it is not and we will be freeing extents
  	 * in this inode then we make the first transaction synchronous
  	 * to make sure that the unlink is permanent by the time we free
  	 * the blocks.
  	 */
  	if (fork == XFS_DATA_FORK) {
  		if (ip->i_d.di_nextents > 0) {
  			/*
  			 * If we are not changing the file size then do
  			 * not update the on-disk file size - we may be
  			 * called from xfs_inactive_free_eofblocks().  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).
  			 */
  			if (ip->i_size != new_size) {
  				ip->i_d.di_size = new_size;
  				ip->i_size = new_size;
  				xfs_trans_log_inode(ntp, ip, XFS_ILOG_CORE);
  			}
  		}
  	} else if (sync) {
  		ASSERT(!(mp->m_flags & XFS_MOUNT_WSYNC));
  		if (ip->i_d.di_anextents > 0)
  			xfs_trans_set_sync(ntp);
  	}
  	ASSERT(fork == XFS_DATA_FORK ||
  		(fork == XFS_ATTR_FORK &&
  			((sync && !(mp->m_flags & XFS_MOUNT_WSYNC)) ||
  			 (sync == 0 && (mp->m_flags & XFS_MOUNT_WSYNC)))));
  
  	/*
  	 * Since it is possible for space to become allocated beyond
  	 * the end of the file (in a crash where the space is allocated
  	 * but the inode size is not yet updated), simply remove any
  	 * blocks which show up between the new EOF and the maximum
  	 * possible file size.  If the first block to be removed is
  	 * beyond the maximum file size (ie it is the same as last_block),
  	 * then there is nothing to do.
  	 */
  	last_block = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_MAXIOFFSET(mp));
  	ASSERT(first_unmap_block <= last_block);
  	done = 0;
  	if (last_block == first_unmap_block) {
  		done = 1;
  	} else {
  		unmap_len = last_block - first_unmap_block + 1;
  	}
  	while (!done) {
  		/*
  		 * Free up up to XFS_ITRUNC_MAX_EXTENTS.  xfs_bunmapi()
  		 * will tell us whether it freed the entire range or
  		 * not.  If this is a synchronous mount (wsync),
  		 * then we can tell bunmapi to keep all the
  		 * transactions asynchronous since the unlink
  		 * transaction that made this inode inactive has
  		 * already hit the disk.  There's no danger of
  		 * the freed blocks being reused, there being a
  		 * crash, and the reused blocks suddenly reappearing
  		 * in this file with garbage in them once recovery
  		 * runs.
  		 */
  		xfs_bmap_init(&free_list, &first_block);
  		error = xfs_bunmapi(ntp, ip,
  				    first_unmap_block, unmap_len,
  				    xfs_bmapi_aflag(fork) |
  				      (sync ? 0 : XFS_BMAPI_ASYNC),
  				    XFS_ITRUNC_MAX_EXTENTS,
  				    &first_block, &free_list,
  				    NULL, &done);
  		if (error) {
  			/*
  			 * If the bunmapi call encounters an error,
  			 * return to the caller where the transaction
  			 * can be properly aborted.  We just need to
  			 * make sure we're not holding any resources
  			 * that we were not when we came in.
  			 */
  			xfs_bmap_cancel(&free_list);
  			return error;
  		}
  
  		/*
  		 * Duplicate the transaction that has the permanent
  		 * reservation and commit the old transaction.
  		 */
  		error = xfs_bmap_finish(tp, &free_list, &committed);
  		ntp = *tp;
  		if (committed) {
  			/* link the inode into the next xact in the chain */
  			xfs_trans_ijoin(ntp, ip,
  					XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
  			xfs_trans_ihold(ntp, ip);
  		}
  
  		if (error) {
  			/*
  			 * If the bmap finish call encounters an error, return
  			 * to the caller where the transaction can be properly
  			 * aborted.  We just need to make sure we're not
  			 * holding any resources that we were not when we came
  			 * in.
  			 *
  			 * Aborting from this point might lose some blocks in
  			 * the file system, but oh well.
  			 */
  			xfs_bmap_cancel(&free_list);
  			return error;
  		}
  
  		if (committed) {
  			/*
  			 * Mark the inode dirty so it will be logged and
  			 * moved forward in the log as part of every commit.
  			 */
  			xfs_trans_log_inode(ntp, ip, XFS_ILOG_CORE);
  		}
  
  		ntp = xfs_trans_dup(ntp);
  		error = xfs_trans_commit(*tp, 0);
  		*tp = ntp;
  
  		/* link the inode into the next transaction in the chain */
  		xfs_trans_ijoin(ntp, ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
  		xfs_trans_ihold(ntp, ip);
  
  		if (error)
  			return error;
  		/*
  		 * transaction commit worked ok so we can drop the extra ticket
  		 * reference that we gained in xfs_trans_dup()
  		 */
  		xfs_log_ticket_put(ntp->t_ticket);
  		error = xfs_trans_reserve(ntp, 0,
  					XFS_ITRUNCATE_LOG_RES(mp), 0,
  					XFS_TRANS_PERM_LOG_RES,
  					XFS_ITRUNCATE_LOG_COUNT);
  		if (error)
  			return error;
  	}
  	/*
  	 * Only update the size in the case of the data fork, but
  	 * always re-log the inode so that our permanent transaction
  	 * can keep on rolling it forward in the log.
  	 */
  	if (fork == XFS_DATA_FORK) {
  		xfs_isize_check(mp, ip, new_size);
  		/*
  		 * If we are not changing the file size then do
  		 * not update the on-disk file size - we may be
  		 * called from xfs_inactive_free_eofblocks().  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).
  		 */
  		if (ip->i_size != new_size) {
  			ip->i_d.di_size = new_size;
  			ip->i_size = new_size;
  		}
  	}
  	xfs_trans_log_inode(ntp, ip, XFS_ILOG_CORE);
  	ASSERT((new_size != 0) ||
  	       (fork == XFS_ATTR_FORK) ||
  	       (ip->i_delayed_blks == 0));
  	ASSERT((new_size != 0) ||
  	       (fork == XFS_ATTR_FORK) ||
  	       (ip->i_d.di_nextents == 0));
  	trace_xfs_itruncate_finish_end(ip, new_size);
  	return 0;
  }
  
  /*
   * This is called when the inode's link count goes to 0.
   * We place the on-disk inode on a list in the AGI.  It
   * will be pulled from this list when the inode is freed.
   */
  int
  xfs_iunlink(
  	xfs_trans_t	*tp,
  	xfs_inode_t	*ip)
  {
  	xfs_mount_t	*mp;
  	xfs_agi_t	*agi;
  	xfs_dinode_t	*dip;
  	xfs_buf_t	*agibp;
  	xfs_buf_t	*ibp;
  	xfs_agino_t	agino;
  	short		bucket_index;
  	int		offset;
  	int		error;
  
  	ASSERT(ip->i_d.di_nlink == 0);
  	ASSERT(ip->i_d.di_mode != 0);
  	ASSERT(ip->i_transp == tp);
  
  	mp = tp->t_mountp;
  
  	/*
  	 * Get the agi buffer first.  It ensures lock ordering
  	 * on the list.
  	 */
  	error = xfs_read_agi(mp, tp, XFS_INO_TO_AGNO(mp, ip->i_ino), &agibp);
  	if (error)
  		return error;
  	agi = XFS_BUF_TO_AGI(agibp);
  
  	/*
  	 * Get the index into the agi hash table for the
  	 * list this inode will go on.
  	 */
  	agino = XFS_INO_TO_AGINO(mp, ip->i_ino);
  	ASSERT(agino != 0);
  	bucket_index = agino % XFS_AGI_UNLINKED_BUCKETS;
  	ASSERT(agi->agi_unlinked[bucket_index]);
  	ASSERT(be32_to_cpu(agi->agi_unlinked[bucket_index]) != agino);
  
  	if (be32_to_cpu(agi->agi_unlinked[bucket_index]) != NULLAGINO) {
  		/*
  		 * There is already another inode in the bucket we need
  		 * to add ourselves to.  Add us at the front of the list.
  		 * Here we put the head pointer into our next pointer,
  		 * and then we fall through to point the head at us.
  		 */
  		error = xfs_itobp(mp, tp, ip, &dip, &ibp, XBF_LOCK);
  		if (error)
  			return error;
  
  		ASSERT(be32_to_cpu(dip->di_next_unlinked) == NULLAGINO);
  		/* both on-disk, don't endian flip twice */
  		dip->di_next_unlinked = agi->agi_unlinked[bucket_index];
  		offset = ip->i_imap.im_boffset +
  			offsetof(xfs_dinode_t, di_next_unlinked);
  		xfs_trans_inode_buf(tp, ibp);
  		xfs_trans_log_buf(tp, ibp, offset,
  				  (offset + sizeof(xfs_agino_t) - 1));
  		xfs_inobp_check(mp, ibp);
  	}
  
  	/*
  	 * Point the bucket head pointer at the inode being inserted.
  	 */
  	ASSERT(agino != 0);
  	agi->agi_unlinked[bucket_index] = cpu_to_be32(agino);
  	offset = offsetof(xfs_agi_t, agi_unlinked) +
  		(sizeof(xfs_agino_t) * bucket_index);
  	xfs_trans_log_buf(tp, agibp, offset,
  			  (offset + sizeof(xfs_agino_t) - 1));
  	return 0;
  }
  
  /*
   * Pull the on-disk inode from the AGI unlinked list.
   */
  STATIC int
  xfs_iunlink_remove(
  	xfs_trans_t	*tp,
  	xfs_inode_t	*ip)
  {
  	xfs_ino_t	next_ino;
  	xfs_mount_t	*mp;
  	xfs_agi_t	*agi;
  	xfs_dinode_t	*dip;
  	xfs_buf_t	*agibp;
  	xfs_buf_t	*ibp;
  	xfs_agnumber_t	agno;
  	xfs_agino_t	agino;
  	xfs_agino_t	next_agino;
  	xfs_buf_t	*last_ibp;
  	xfs_dinode_t	*last_dip = NULL;
  	short		bucket_index;
  	int		offset, last_offset = 0;
  	int		error;
  
  	mp = tp->t_mountp;
  	agno = XFS_INO_TO_AGNO(mp, ip->i_ino);
  
  	/*
  	 * Get the agi buffer first.  It ensures lock ordering
  	 * on the list.
  	 */
  	error = xfs_read_agi(mp, tp, agno, &agibp);
  	if (error)
  		return error;
  
  	agi = XFS_BUF_TO_AGI(agibp);
  
  	/*
  	 * Get the index into the agi hash table for the
  	 * list this inode will go on.
  	 */
  	agino = XFS_INO_TO_AGINO(mp, ip->i_ino);
  	ASSERT(agino != 0);
  	bucket_index = agino % XFS_AGI_UNLINKED_BUCKETS;
  	ASSERT(be32_to_cpu(agi->agi_unlinked[bucket_index]) != NULLAGINO);
  	ASSERT(agi->agi_unlinked[bucket_index]);
  
  	if (be32_to_cpu(agi->agi_unlinked[bucket_index]) == agino) {
  		/*
  		 * We're at the head of the list.  Get the inode's
  		 * on-disk buffer to see if there is anyone after us
  		 * on the list.  Only modify our next pointer if it
  		 * is not already NULLAGINO.  This saves us the overhead
  		 * of dealing with the buffer when there is no need to
  		 * change it.
  		 */
  		error = xfs_itobp(mp, tp, ip, &dip, &ibp, XBF_LOCK);
  		if (error) {
  			cmn_err(CE_WARN,
  				"xfs_iunlink_remove: xfs_itobp()  returned an error %d on %s.  Returning error.",
  				error, mp->m_fsname);
  			return error;
  		}
  		next_agino = be32_to_cpu(dip->di_next_unlinked);
  		ASSERT(next_agino != 0);
  		if (next_agino != NULLAGINO) {
  			dip->di_next_unlinked = cpu_to_be32(NULLAGINO);
  			offset = ip->i_imap.im_boffset +
  				offsetof(xfs_dinode_t, di_next_unlinked);
  			xfs_trans_inode_buf(tp, ibp);
  			xfs_trans_log_buf(tp, ibp, offset,
  					  (offset + sizeof(xfs_agino_t) - 1));
  			xfs_inobp_check(mp, ibp);
  		} else {
  			xfs_trans_brelse(tp, ibp);
  		}
  		/*
  		 * Point the bucket head pointer at the next inode.
  		 */
  		ASSERT(next_agino != 0);
  		ASSERT(next_agino != agino);
  		agi->agi_unlinked[bucket_index] = cpu_to_be32(next_agino);
  		offset = offsetof(xfs_agi_t, agi_unlinked) +
  			(sizeof(xfs_agino_t) * bucket_index);
  		xfs_trans_log_buf(tp, agibp, offset,
  				  (offset + sizeof(xfs_agino_t) - 1));
  	} else {
  		/*
  		 * We need to search the list for the inode being freed.
  		 */
  		next_agino = be32_to_cpu(agi->agi_unlinked[bucket_index]);
  		last_ibp = NULL;
  		while (next_agino != agino) {
  			/*
  			 * If the last inode wasn't the one pointing to
  			 * us, then release its buffer since we're not
  			 * going to do anything with it.
  			 */
  			if (last_ibp != NULL) {
  				xfs_trans_brelse(tp, last_ibp);
  			}
  			next_ino = XFS_AGINO_TO_INO(mp, agno, next_agino);
  			error = xfs_inotobp(mp, tp, next_ino, &last_dip,
  					    &last_ibp, &last_offset, 0);
  			if (error) {
  				cmn_err(CE_WARN,
  			"xfs_iunlink_remove: xfs_inotobp()  returned an error %d on %s.  Returning error.",
  					error, mp->m_fsname);
  				return error;
  			}
  			next_agino = be32_to_cpu(last_dip->di_next_unlinked);
  			ASSERT(next_agino != NULLAGINO);
  			ASSERT(next_agino != 0);
  		}
  		/*
  		 * Now last_ibp points to the buffer previous to us on
  		 * the unlinked list.  Pull us from the list.
  		 */
  		error = xfs_itobp(mp, tp, ip, &dip, &ibp, XBF_LOCK);
  		if (error) {
  			cmn_err(CE_WARN,
  				"xfs_iunlink_remove: xfs_itobp()  returned an error %d on %s.  Returning error.",
  				error, mp->m_fsname);
  			return error;
  		}
  		next_agino = be32_to_cpu(dip->di_next_unlinked);
  		ASSERT(next_agino != 0);
  		ASSERT(next_agino != agino);
  		if (next_agino != NULLAGINO) {
  			dip->di_next_unlinked = cpu_to_be32(NULLAGINO);
  			offset = ip->i_imap.im_boffset +
  				offsetof(xfs_dinode_t, di_next_unlinked);
  			xfs_trans_inode_buf(tp, ibp);
  			xfs_trans_log_buf(tp, ibp, offset,
  					  (offset + sizeof(xfs_agino_t) - 1));
  			xfs_inobp_check(mp, ibp);
  		} else {
  			xfs_trans_brelse(tp, ibp);
  		}
  		/*
  		 * Point the previous inode on the list to the next inode.
  		 */
  		last_dip->di_next_unlinked = cpu_to_be32(next_agino);
  		ASSERT(next_agino != 0);
  		offset = last_offset + offsetof(xfs_dinode_t, di_next_unlinked);
  		xfs_trans_inode_buf(tp, last_ibp);
  		xfs_trans_log_buf(tp, last_ibp, offset,
  				  (offset + sizeof(xfs_agino_t) - 1));
  		xfs_inobp_check(mp, last_ibp);
  	}
  	return 0;
  }
  
  STATIC void
  xfs_ifree_cluster(
  	xfs_inode_t	*free_ip,
  	xfs_trans_t	*tp,
  	xfs_ino_t	inum)
  {
  	xfs_mount_t		*mp = free_ip->i_mount;
  	int			blks_per_cluster;
  	int			nbufs;
  	int			ninodes;
  	int			i, j;
  	xfs_daddr_t		blkno;
  	xfs_buf_t		*bp;
  	xfs_inode_t		*ip;
  	xfs_inode_log_item_t	*iip;
  	xfs_log_item_t		*lip;
  	struct xfs_perag	*pag;
  
  	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, inum));
  	if (mp->m_sb.sb_blocksize >= XFS_INODE_CLUSTER_SIZE(mp)) {
  		blks_per_cluster = 1;
  		ninodes = mp->m_sb.sb_inopblock;
  		nbufs = XFS_IALLOC_BLOCKS(mp);
  	} else {
  		blks_per_cluster = XFS_INODE_CLUSTER_SIZE(mp) /
  					mp->m_sb.sb_blocksize;
  		ninodes = blks_per_cluster * mp->m_sb.sb_inopblock;
  		nbufs = XFS_IALLOC_BLOCKS(mp) / blks_per_cluster;
  	}
  
  	for (j = 0; j < nbufs; j++, inum += ninodes) {
  		int	found = 0;
  
  		blkno = XFS_AGB_TO_DADDR(mp, XFS_INO_TO_AGNO(mp, inum),
  					 XFS_INO_TO_AGBNO(mp, inum));
  
  		/*
  		 * We obtain and lock the backing buffer first in the process
  		 * here, as we have to ensure that any dirty inode that we
  		 * can't get the flush lock on is attached to the buffer.
  		 * If we scan the in-memory inodes first, then buffer IO can
  		 * complete before we get a lock on it, and hence we may fail
  		 * to mark all the active inodes on the buffer stale.
  		 */
  		bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, blkno,
  					mp->m_bsize * blks_per_cluster,
  					XBF_LOCK);
  
  		/*
  		 * Walk the inodes already attached to the buffer and mark them
  		 * stale. These will all have the flush locks held, so an
  		 * in-memory inode walk can't lock them.
  		 */
  		lip = XFS_BUF_FSPRIVATE(bp, xfs_log_item_t *);
  		while (lip) {
  			if (lip->li_type == XFS_LI_INODE) {
  				iip = (xfs_inode_log_item_t *)lip;
  				ASSERT(iip->ili_logged == 1);
  				lip->li_cb = (void(*)(xfs_buf_t*,xfs_log_item_t*)) xfs_istale_done;
  				xfs_trans_ail_copy_lsn(mp->m_ail,
  							&iip->ili_flush_lsn,
  							&iip->ili_item.li_lsn);
  				xfs_iflags_set(iip->ili_inode, XFS_ISTALE);
  				found++;
  			}
  			lip = lip->li_bio_list;
  		}
  
  		/*
  		 * For each inode in memory attempt to add it to the inode
  		 * buffer and set it up for being staled on buffer IO
  		 * completion.  This is safe as we've locked out tail pushing
  		 * and flushing by locking the buffer.
  		 *
  		 * We have already marked every inode that was part of a
  		 * transaction stale above, which means there is no point in
  		 * even trying to lock them.
  		 */
  		for (i = 0; i < ninodes; i++) {
  			read_lock(&pag->pag_ici_lock);
  			ip = radix_tree_lookup(&pag->pag_ici_root,
  					XFS_INO_TO_AGINO(mp, (inum + i)));
  
  			/* Inode not in memory or stale, nothing to do */
  			if (!ip || xfs_iflags_test(ip, XFS_ISTALE)) {
  				read_unlock(&pag->pag_ici_lock);
  				continue;
  			}
  
  			/* don't try to lock/unlock the current inode */
  			if (ip != free_ip &&
  			    !xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) {
  				read_unlock(&pag->pag_ici_lock);
  				continue;
  			}
  			read_unlock(&pag->pag_ici_lock);
  
  			if (!xfs_iflock_nowait(ip)) {
  				if (ip != free_ip)
  					xfs_iunlock(ip, XFS_ILOCK_EXCL);
  				continue;
  			}
  
  			xfs_iflags_set(ip, XFS_ISTALE);
  			if (xfs_inode_clean(ip)) {
  				ASSERT(ip != free_ip);
  				xfs_ifunlock(ip);
  				xfs_iunlock(ip, XFS_ILOCK_EXCL);
  				continue;
  			}
  
  			iip = ip->i_itemp;
  			if (!iip) {
  				/* inode with unlogged changes only */
  				ASSERT(ip != free_ip);
  				ip->i_update_core = 0;
  				xfs_ifunlock(ip);
  				xfs_iunlock(ip, XFS_ILOCK_EXCL);
  				continue;
  			}
  			found++;
  
  			iip->ili_last_fields = iip->ili_format.ilf_fields;
  			iip->ili_format.ilf_fields = 0;
  			iip->ili_logged = 1;
  			xfs_trans_ail_copy_lsn(mp->m_ail, &iip->ili_flush_lsn,
  						&iip->ili_item.li_lsn);
  
  			xfs_buf_attach_iodone(bp,
  				(void(*)(xfs_buf_t*,xfs_log_item_t*))
  				xfs_istale_done, (xfs_log_item_t *)iip);
  
  			if (ip != free_ip)
  				xfs_iunlock(ip, XFS_ILOCK_EXCL);
  		}
  
  		if (found)
  			xfs_trans_stale_inode_buf(tp, bp);
  		xfs_trans_binval(tp, bp);
  	}
  
  	xfs_perag_put(pag);
  }
  
  /*
   * This is called to return an inode to the inode free list.
   * The inode should already be truncated to 0 length and have
   * no pages associated with it.  This routine also assumes that
   * the inode is already a part of the transaction.
   *
   * The on-disk copy of the inode will have been added to the list
   * of unlinked inodes in the AGI. We need to remove the inode from
   * that list atomically with respect to freeing it here.
   */
  int
  xfs_ifree(
  	xfs_trans_t	*tp,
  	xfs_inode_t	*ip,
  	xfs_bmap_free_t	*flist)
  {
  	int			error;
  	int			delete;
  	xfs_ino_t		first_ino;
  	xfs_dinode_t    	*dip;
  	xfs_buf_t       	*ibp;
  
  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
  	ASSERT(ip->i_transp == tp);
  	ASSERT(ip->i_d.di_nlink == 0);
  	ASSERT(ip->i_d.di_nextents == 0);
  	ASSERT(ip->i_d.di_anextents == 0);
  	ASSERT((ip->i_d.di_size == 0 && ip->i_size == 0) ||
  	       ((ip->i_d.di_mode & S_IFMT) != S_IFREG));
  	ASSERT(ip->i_d.di_nblocks == 0);
  
  	/*
  	 * Pull the on-disk inode from the AGI unlinked list.
  	 */
  	error = xfs_iunlink_remove(tp, ip);
  	if (error != 0) {
  		return error;
  	}
  
  	error = xfs_difree(tp, ip->i_ino, flist, &delete, &first_ino);
  	if (error != 0) {
  		return error;
  	}
  	ip->i_d.di_mode = 0;		/* mark incore inode as free */
  	ip->i_d.di_flags = 0;
  	ip->i_d.di_dmevmask = 0;
  	ip->i_d.di_forkoff = 0;		/* mark the attr fork not in use */
  	ip->i_df.if_ext_max =
  		XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t);
  	ip->i_d.di_format = XFS_DINODE_FMT_EXTENTS;
  	ip->i_d.di_aformat = XFS_DINODE_FMT_EXTENTS;
  	/*
  	 * Bump the generation count so no one will be confused
  	 * by reincarnations of this inode.
  	 */
  	ip->i_d.di_gen++;
  
  	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
  
  	error = xfs_itobp(ip->i_mount, tp, ip, &dip, &ibp, XBF_LOCK);
  	if (error)
  		return error;
  
          /*
  	* Clear the on-disk di_mode. This is to prevent xfs_bulkstat
  	* from picking up this inode when it is reclaimed (its incore state
  	* initialzed but not flushed to disk yet). The in-core di_mode is
  	* already cleared  and a corresponding transaction logged.
  	* The hack here just synchronizes the in-core to on-disk
  	* di_mode value in advance before the actual inode sync to disk.
  	* This is OK because the inode is already unlinked and would never
  	* change its di_mode again for this inode generation.
  	* This is a temporary hack that would require a proper fix
  	* in the future.
  	*/
  	dip->di_mode = 0;
  
  	if (delete) {
  		xfs_ifree_cluster(ip, tp, first_ino);
  	}
  
  	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));
  }
  
  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;
  	}
  }
  
  /*
   * This is called to unpin an inode.  The caller must have the inode locked
   * in at least shared mode so that the buffer cannot be subsequently pinned
   * once someone is waiting for it to be unpinned.
   */
  static void
  xfs_iunpin_nowait(
  	struct xfs_inode	*ip)
  {
  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
  
  	trace_xfs_inode_unpin_nowait(ip, _RET_IP_);
  
  	/* Give the log a push to start the unpinning I/O */
  	xfs_log_force_lsn(ip->i_mount, ip->i_itemp->ili_last_lsn, 0);
  
  }
  
  void
  xfs_iunpin_wait(
  	struct xfs_inode	*ip)
  {
  	if (xfs_ipincount(ip)) {
  		xfs_iunpin_nowait(ip);
  		wait_event(ip->i_ipin_wait, (xfs_ipincount(ip) == 0));
  	}
  }
  
  /*
   * 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.
   */
  /*ARGSUSED*/
  STATIC 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);
  			xfs_dinode_put_rdev(dip, 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(XFS_DFORK_DPTR(dip),
  			       &ip->i_df.if_u2.if_uuid,
  			       sizeof(uuid_t));
  		}
  		break;
  
  	default:
  		ASSERT(0);
  		break;
  	}
  }
  
  STATIC int
  xfs_iflush_cluster(
  	xfs_inode_t	*ip,
  	xfs_buf_t	*bp)
  {
  	xfs_mount_t		*mp = ip->i_mount;
  	struct xfs_perag	*pag;
  	unsigned long		first_index, mask;
  	unsigned long		inodes_per_cluster;
  	int			ilist_size;
  	xfs_inode_t		**ilist;
  	xfs_inode_t		*iq;
  	int			nr_found;
  	int			clcount = 0;
  	int			bufwasdelwri;
  	int			i;
  
  	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
  
  	inodes_per_cluster = XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_inodelog;
  	ilist_size = inodes_per_cluster * sizeof(xfs_inode_t *);
  	ilist = kmem_alloc(ilist_size, KM_MAYFAIL|KM_NOFS);
  	if (!ilist)
  		goto out_put;
  
  	mask = ~(((XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_inodelog)) - 1);
  	first_index = XFS_INO_TO_AGINO(mp, ip->i_ino) & mask;
  	read_lock(&pag->pag_ici_lock);
  	/* really need a gang lookup range call here */
  	nr_found = radix_tree_gang_lookup(&pag->pag_ici_root, (void**)ilist,
  					first_index, inodes_per_cluster);
  	if (nr_found == 0)
  		goto out_free;
  
  	for (i = 0; i < nr_found; i++) {
  		iq = ilist[i];
  		if (iq == ip)
  			continue;
  		/* if the inode lies outside this cluster, we're done. */
  		if ((XFS_INO_TO_AGINO(mp, iq->i_ino) & mask) != first_index)
  			break;
  		/*
  		 * Do an un-protected check to see if the inode is dirty and
  		 * is a candidate for flushing.  These checks will be repeated
  		 * later after the appropriate locks are acquired.
  		 */
  		if (xfs_inode_clean(iq) && xfs_ipincount(iq) == 0)
  			continue;
  
  		/*
  		 * Try to get locks.  If any are unavailable or it is pinned,
  		 * then this inode cannot be flushed and is skipped.
  		 */
  
  		if (!xfs_ilock_nowait(iq, XFS_ILOCK_SHARED))
  			continue;
  		if (!xfs_iflock_nowait(iq)) {
  			xfs_iunlock(iq, XFS_ILOCK_SHARED);
  			continue;
  		}
  		if (xfs_ipincount(iq)) {
  			xfs_ifunlock(iq);
  			xfs_iunlock(iq, XFS_ILOCK_SHARED);
  			continue;
  		}
  
  		/*
  		 * arriving here means that this inode can be flushed.  First
  		 * re-check that it's dirty before flushing.
  		 */
  		if (!xfs_inode_clean(iq)) {
  			int	error;
  			error = xfs_iflush_int(iq, bp);
  			if (error) {
  				xfs_iunlock(iq, XFS_ILOCK_SHARED);
  				goto cluster_corrupt_out;
  			}
  			clcount++;
  		} else {
  			xfs_ifunlock(iq);
  		}
  		xfs_iunlock(iq, XFS_ILOCK_SHARED);
  	}
  
  	if (clcount) {
  		XFS_STATS_INC(xs_icluster_flushcnt);
  		XFS_STATS_ADD(xs_icluster_flushinode, clcount);
  	}
  
  out_free:
  	read_unlock(&pag->pag_ici_lock);
  	kmem_free(ilist);
  out_put:
  	xfs_perag_put(pag);
  	return 0;
  
  
  cluster_corrupt_out:
  	/*
  	 * Corruption detected in the clustering loop.  Invalidate the
  	 * inode buffer and shut down the filesystem.
  	 */
  	read_unlock(&pag->pag_ici_lock);
  	/*
  	 * Clean up the buffer.  If it was B_DELWRI, just release it --
  	 * brelse can handle it with no problems.  If not, shut down the
  	 * filesystem before releasing the buffer.
  	 */
  	bufwasdelwri = XFS_BUF_ISDELAYWRITE(bp);
  	if (bufwasdelwri)
  		xfs_buf_relse(bp);
  
  	xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
  
  	if (!bufwasdelwri) {
  		/*
  		 * Just like incore_relse: if we have b_iodone functions,
  		 * mark the buffer as an error and call them.  Otherwise
  		 * mark it as stale and brelse.
  		 */
  		if (XFS_BUF_IODONE_FUNC(bp)) {
  			XFS_BUF_CLR_BDSTRAT_FUNC(bp);
  			XFS_BUF_UNDONE(bp);
  			XFS_BUF_STALE(bp);
  			XFS_BUF_ERROR(bp,EIO);
  			xfs_biodone(bp);
  		} else {
  			XFS_BUF_STALE(bp);
  			xfs_buf_relse(bp);
  		}
  	}
  
  	/*
  	 * Unlocks the flush lock
  	 */
  	xfs_iflush_abort(iq);
  	kmem_free(ilist);
  	xfs_perag_put(pag);
  	return XFS_ERROR(EFSCORRUPTED);
  }
  
  /*
   * xfs_iflush() will write a modified inode's changes out to the
   * inode's on disk home.  The caller must have the inode lock held
   * in at least shared mode and the inode flush completion must be
   * active as well.  The inode lock will still be held upon return from
   * the call and the caller is free to unlock it.
   * The inode flush will be completed when the inode reaches the disk.
   * The flags indicate how the inode's buffer should be written out.
   */
  int
  xfs_iflush(
  	xfs_inode_t		*ip,
  	uint			flags)
  {
  	xfs_inode_log_item_t	*iip;
  	xfs_buf_t		*bp;
  	xfs_dinode_t		*dip;
  	xfs_mount_t		*mp;
  	int			error;
  
  	XFS_STATS_INC(xs_iflush_count);
  
  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
  	ASSERT(!completion_done(&ip->i_flush));
  	ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
  	       ip->i_d.di_nextents > ip->i_df.if_ext_max);
  
  	iip = ip->i_itemp;
  	mp = ip->i_mount;
  
  	/*
  	 * We can't flush the inode until it is unpinned, so wait for it if we
  	 * are allowed to block.  We know noone new can pin it, because we are
  	 * holding the inode lock shared and you need to hold it exclusively to
  	 * pin the inode.
  	 *
  	 * If we are not allowed to block, force the log out asynchronously so
  	 * that when we come back the inode will be unpinned. If other inodes
  	 * in the same cluster are dirty, they will probably write the inode
  	 * out for us if they occur after the log force completes.
  	 */
  	if (!(flags & SYNC_WAIT) && xfs_ipincount(ip)) {
  		xfs_iunpin_nowait(ip);
  		xfs_ifunlock(ip);
  		return EAGAIN;
  	}
  	xfs_iunpin_wait(ip);
  
  	/*
  	 * For stale inodes we cannot rely on the backing buffer remaining
  	 * stale in cache for the remaining life of the stale inode and so
  	 * xfs_itobp() below may give us a buffer that no longer contains
  	 * inodes below. We have to check this after ensuring the inode is
  	 * unpinned so that it is safe to reclaim the stale inode after the
  	 * flush call.
  	 */
  	if (xfs_iflags_test(ip, XFS_ISTALE)) {
  		xfs_ifunlock(ip);
  		return 0;
  	}
  
  	/*
  	 * This may have been unpinned because the filesystem is shutting
  	 * down forcibly. If that's the case we must not write this inode
  	 * to disk, because the log record didn't make it to disk!
  	 */
  	if (XFS_FORCED_SHUTDOWN(mp)) {
  		ip->i_update_core = 0;
  		if (iip)
  			iip->ili_format.ilf_fields = 0;
  		xfs_ifunlock(ip);
  		return XFS_ERROR(EIO);
  	}
  
  	/*
  	 * Get the buffer containing the on-disk inode.
  	 */
  	error = xfs_itobp(mp, NULL, ip, &dip, &bp,
  				(flags & SYNC_WAIT) ? XBF_LOCK : XBF_TRYLOCK);
  	if (error || !bp) {
  		xfs_ifunlock(ip);
  		return error;
  	}
  
  	/*
  	 * First flush out the inode that xfs_iflush was called with.
  	 */
  	error = xfs_iflush_int(ip, bp);
  	if (error)
  		goto corrupt_out;
  
  	/*
  	 * If the buffer is pinned then push on the log now so we won't
  	 * get stuck waiting in the write for too long.
  	 */
  	if (XFS_BUF_ISPINNED(bp))
  		xfs_log_force(mp, 0);
  
  	/*
  	 * inode clustering:
  	 * see if other inodes can be gathered into this write
  	 */
  	error = xfs_iflush_cluster(ip, bp);
  	if (error)
  		goto cluster_corrupt_out;
  
  	if (flags & SYNC_WAIT)
  		error = xfs_bwrite(mp, bp);
  	else
  		xfs_bdwrite(mp, bp);
  	return error;
  
  corrupt_out:
  	xfs_buf_relse(bp);
  	xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
  cluster_corrupt_out:
  	/*
  	 * Unlocks the flush lock
  	 */
  	xfs_iflush_abort(ip);
  	return XFS_ERROR(EFSCORRUPTED);
  }
  
  
  STATIC int
  xfs_iflush_int(
  	xfs_inode_t		*ip,
  	xfs_buf_t		*bp)
  {
  	xfs_inode_log_item_t	*iip;
  	xfs_dinode_t		*dip;
  	xfs_mount_t		*mp;
  #ifdef XFS_TRANS_DEBUG
  	int			first;
  #endif
  
  	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
  	ASSERT(!completion_done(&ip->i_flush));
  	ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
  	       ip->i_d.di_nextents > ip->i_df.if_ext_max);
  
  	iip = ip->i_itemp;
  	mp = ip->i_mount;
  
  	/* set *dip = inode's place in the buffer */
  	dip = (xfs_dinode_t *)xfs_buf_offset(bp, ip->i_imap.im_boffset);
  
  	/*
  	 * Clear i_update_core before copying out the data.
  	 * This is for coordination with our timestamp updates
  	 * that don't hold the inode lock. They will always
  	 * update the timestamps BEFORE setting i_update_core,
  	 * so if we clear i_update_core after they set it we
  	 * are guaranteed to see their updates to the timestamps.
  	 * I believe that this depends on strongly ordered memory
  	 * semantics, but we have that.  We use the SYNCHRONIZE
  	 * macro to make sure that the compiler does not reorder
  	 * the i_update_core access below the data copy below.
  	 */
  	ip->i_update_core = 0;
  	SYNCHRONIZE();
  
  	/*
  	 * Make sure to get the latest timestamps from the Linux inode.
  	 */
  	xfs_synchronize_times(ip);
  
  	if (XFS_TEST_ERROR(be16_to_cpu(dip->di_magic) != XFS_DINODE_MAGIC,
  			       mp, XFS_ERRTAG_IFLUSH_1, XFS_RANDOM_IFLUSH_1)) {
  		xfs_cmn_err(XFS_PTAG_IFLUSH, CE_ALERT, mp,
  		    "xfs_iflush: Bad inode %Lu magic number 0x%x, ptr 0x%p",
  			ip->i_ino, be16_to_cpu(dip->di_magic), dip);
  		goto corrupt_out;
  	}
  	if (XFS_TEST_ERROR(ip->i_d.di_magic != XFS_DINODE_MAGIC,
  				mp, XFS_ERRTAG_IFLUSH_2, XFS_RANDOM_IFLUSH_2)) {
  		xfs_cmn_err(XFS_PTAG_IFLUSH, CE_ALERT, mp,
  			"xfs_iflush: Bad inode %Lu, ptr 0x%p, magic number 0x%x",
  			ip->i_ino, ip, ip->i_d.di_magic);
  		goto corrupt_out;
  	}
  	if ((ip->i_d.di_mode & S_IFMT) == S_IFREG) {
  		if (XFS_TEST_ERROR(
  		    (ip->i_d.di_format != XFS_DINODE_FMT_EXTENTS) &&
  		    (ip->i_d.di_format != XFS_DINODE_FMT_BTREE),
  		    mp, XFS_ERRTAG_IFLUSH_3, XFS_RANDOM_IFLUSH_3)) {
  			xfs_cmn_err(XFS_PTAG_IFLUSH, CE_ALERT, mp,
  				"xfs_iflush: Bad regular inode %Lu, ptr 0x%p",
  				ip->i_ino, ip);
  			goto corrupt_out;
  		}
  	} else if ((ip->i_d.di_mode & S_IFMT) == S_IFDIR) {
  		if (XFS_TEST_ERROR(
  		    (ip->i_d.di_format != XFS_DINODE_FMT_EXTENTS) &&
  		    (ip->i_d.di_format != XFS_DINODE_FMT_BTREE) &&
  		    (ip->i_d.di_format != XFS_DINODE_FMT_LOCAL),
  		    mp, XFS_ERRTAG_IFLUSH_4, XFS_RANDOM_IFLUSH_4)) {
  			xfs_cmn_err(XFS_PTAG_IFLUSH, CE_ALERT, mp,
  				"xfs_iflush: Bad directory inode %Lu, ptr 0x%p",
  				ip->i_ino, ip);
  			goto corrupt_out;
  		}
  	}
  	if (XFS_TEST_ERROR(ip->i_d.di_nextents + ip->i_d.di_anextents >
  				ip->i_d.di_nblocks, mp, XFS_ERRTAG_IFLUSH_5,
  				XFS_RANDOM_IFLUSH_5)) {
  		xfs_cmn_err(XFS_PTAG_IFLUSH, CE_ALERT, mp,
  			"xfs_iflush: detected corrupt incore inode %Lu, total extents = %d, nblocks = %Ld, ptr 0x%p",
  			ip->i_ino,
  			ip->i_d.di_nextents + ip->i_d.di_anextents,
  			ip->i_d.di_nblocks,
  			ip);
  		goto corrupt_out;
  	}
  	if (XFS_TEST_ERROR(ip->i_d.di_forkoff > mp->m_sb.sb_inodesize,
  				mp, XFS_ERRTAG_IFLUSH_6, XFS_RANDOM_IFLUSH_6)) {
  		xfs_cmn_err(XFS_PTAG_IFLUSH, CE_ALERT, mp,
  			"xfs_iflush: bad inode %Lu, forkoff 0x%x, ptr 0x%p",
  			ip->i_ino, ip->i_d.di_forkoff, ip);
  		goto corrupt_out;
  	}
  	/*
  	 * bump the flush iteration count, used to detect flushes which
  	 * postdate a log record during recovery.
  	 */
  
  	ip->i_d.di_flushiter++;
  
  	/*
  	 * Copy the dirty parts of the inode into the on-disk
  	 * inode.  We always copy out the core of the inode,
  	 * because if the inode is dirty at all the core must
  	 * be.
  	 */
  	xfs_dinode_to_disk(dip, &ip->i_d);
  
  	/* Wrap, we never let the log put out DI_MAX_FLUSH */
  	if (ip->i_d.di_flushiter == DI_MAX_FLUSH)
  		ip->i_d.di_flushiter = 0;
  
  	/*
  	 * If this is really an old format inode and the superblock version
  	 * has not been updated to support only new format inodes, then
  	 * convert back to the old inode format.  If the superblock version
  	 * has been updated, then make the conversion permanent.
  	 */
  	ASSERT(ip->i_d.di_version == 1 || xfs_sb_version_hasnlink(&mp->m_sb));
  	if (ip->i_d.di_version == 1) {
  		if (!xfs_sb_version_hasnlink(&mp->m_sb)) {
  			/*
  			 * Convert it back.
  			 */
  			ASSERT(ip->i_d.di_nlink <= XFS_MAXLINK_1);
  			dip->di_onlink = cpu_to_be16(ip->i_d.di_nlink);
  		} else {
  			/*
  			 * The superblock version has already been bumped,
  			 * so just make the conversion to the new inode
  			 * format permanent.
  			 */
  			ip->i_d.di_version = 2;
  			dip->di_version = 2;
  			ip->i_d.di_onlink = 0;
  			dip->di_onlink = 0;
  			memset(&(ip->i_d.di_pad[0]), 0, sizeof(ip->i_d.di_pad));
  			memset(&(dip->di_pad[0]), 0,
  			      sizeof(dip->di_pad));
  			ASSERT(ip->i_d.di_projid == 0);
  		}
  	}
  
  	xfs_iflush_fork(ip, dip, iip, XFS_DATA_FORK, bp);
  	if (XFS_IFORK_Q(ip))
  		xfs_iflush_fork(ip, dip, iip, XFS_ATTR_FORK, bp);
  	xfs_inobp_check(mp, bp);
  
  	/*
  	 * We've recorded everything logged in the inode, so we'd
  	 * like to clear the ilf_fields bits so we don't log and
  	 * flush things unnecessarily.  However, we can't stop
  	 * logging all this information until the data we've copied
  	 * into the disk buffer is written to disk.  If we did we might
  	 * overwrite the copy of the inode in the log with all the
  	 * data after re-logging only part of it, and in the face of
  	 * a crash we wouldn't have all the data we need to recover.
  	 *
  	 * What we do is move the bits to the ili_last_fields field.
  	 * When logging the inode, these bits are moved back to the
  	 * ilf_fields field.  In the xfs_iflush_done() routine we
  	 * clear ili_last_fields, since we know that the information
  	 * those bits represent is permanently on disk.  As long as
  	 * the flush completes before the inode is logged again, then
  	 * both ilf_fields and ili_last_fields will be cleared.
  	 *
  	 * We can play with the ilf_fields bits here, because the inode
  	 * lock must be held exclusively in order to set bits there
  	 * and the flush lock protects the ili_last_fields bits.
  	 * Set ili_logged so the flush done
  	 * routine can tell whether or not to look in the AIL.
  	 * Also, store the current LSN of the inode so that we can tell
  	 * whether the item has moved in the AIL from xfs_iflush_done().
  	 * In order to read the lsn we need the AIL lock, because
  	 * it is a 64 bit value that cannot be read atomically.
  	 */
  	if (iip != NULL && iip->ili_format.ilf_fields != 0) {
  		iip->ili_last_fields = iip->ili_format.ilf_fields;
  		iip->ili_format.ilf_fields = 0;
  		iip->ili_logged = 1;
  
  		xfs_trans_ail_copy_lsn(mp->m_ail, &iip->ili_flush_lsn,
  					&iip->ili_item.li_lsn);
  
  		/*
  		 * Attach the function xfs_iflush_done to the inode's
  		 * buffer.  This will remove the inode from the AIL
  		 * and unlock the inode's flush lock when the inode is
  		 * completely written to disk.
  		 */
  		xfs_buf_attach_iodone(bp, (void(*)(xfs_buf_t*,xfs_log_item_t*))
  				      xfs_iflush_done, (xfs_log_item_t *)iip);
  
  		ASSERT(XFS_BUF_FSPRIVATE(bp, void *) != NULL);
  		ASSERT(XFS_BUF_IODONE_FUNC(bp) != NULL);
  	} else {
  		/*
  		 * We're flushing an inode which is not in the AIL and has
  		 * not been logged but has i_update_core set.  For this
  		 * case we can use a B_DELWRI flush and immediately drop
  		 * the inode flush lock because we can avoid the whole
  		 * AIL state thing.  It's OK to drop the flush lock now,
  		 * because we've already locked the buffer and to do anything
  		 * you really need both.
  		 */
  		if (iip != NULL) {
  			ASSERT(iip->ili_logged == 0);
  			ASSERT(iip->ili_last_fields == 0);
  			ASSERT((iip->ili_item.li_flags & XFS_LI_IN_AIL) == 0);
  		}
  		xfs_ifunlock(ip);
  	}
  
  	return 0;
  
  corrupt_out:
  	return XFS_ERROR(EFSCORRUPTED);
  }
  
  /*
   * 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_inode_t	*ip,		/* incore inode 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 */
  	int		state)		/* type of extent conversion */
  {
  	xfs_ifork_t	*ifp = (state & BMAP_ATTRFORK) ? ip->i_afp : &ip->i_df;
  	xfs_extnum_t	i;		/* extent record index */
  
  	trace_xfs_iext_insert(ip, idx, new, state, _RET_IP_);
  
  	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_inode_t	*ip,		/* incore inode pointer */
  	xfs_extnum_t	idx,		/* index to begin removing exts */
  	int		ext_diff,	/* number of extents to remove */
  	int		state)		/* type of extent conversion */
  {
  	xfs_ifork_t	*ifp = (state & BMAP_ATTRFORK) ? ip->i_afp : &ip->i_df;
  	xfs_extnum_t	nextents;	/* number of extents in file */
  	int		new_size;	/* size of extents after removal */
  
  	trace_xfs_iext_remove(ip, idx, state, _RET_IP_);
  
  	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.
   */
  STATIC 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.
   */
  STATIC 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;
  	}
  }
  