xfs: fix filesystsem freeze race in xfs_trans_alloc

[mirror_ubuntu-artful-kernel.git] / fs / xfs / xfs_bmap.c

/*
 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#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_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_mount.h"
#include "xfs_itable.h"
#include "xfs_dir2_data.h"
#include "xfs_dir2_leaf.h"
#include "xfs_dir2_block.h"
#include "xfs_inode_item.h"
#include "xfs_extfree_item.h"
#include "xfs_alloc.h"
#include "xfs_bmap.h"
#include "xfs_rtalloc.h"
#include "xfs_error.h"
#include "xfs_attr_leaf.h"
#include "xfs_rw.h"
#include "xfs_quota.h"
#include "xfs_trans_space.h"
#include "xfs_buf_item.h"
#include "xfs_filestream.h"
#include "xfs_vnodeops.h"
#include "xfs_trace.h"


#ifdef DEBUG
STATIC void
xfs_bmap_check_leaf_extents(xfs_btree_cur_t *cur, xfs_inode_t *ip, int whichfork);
#endif

kmem_zone_t		*xfs_bmap_free_item_zone;

/*
 * Prototypes for internal bmap routines.
 */


/*
 * Called from xfs_bmap_add_attrfork to handle extents format files.
 */
STATIC int					/* error */
xfs_bmap_add_attrfork_extents(
	xfs_trans_t		*tp,		/* transaction pointer */
	xfs_inode_t		*ip,		/* incore inode pointer */
	xfs_fsblock_t		*firstblock,	/* first block allocated */
	xfs_bmap_free_t		*flist,		/* blocks to free at commit */
	int			*flags);	/* inode logging flags */

/*
 * Called from xfs_bmap_add_attrfork to handle local format files.
 */
STATIC int					/* error */
xfs_bmap_add_attrfork_local(
	xfs_trans_t		*tp,		/* transaction pointer */
	xfs_inode_t		*ip,		/* incore inode pointer */
	xfs_fsblock_t		*firstblock,	/* first block allocated */
	xfs_bmap_free_t		*flist,		/* blocks to free at commit */
	int			*flags);	/* inode logging flags */

/*
 * Called by xfs_bmap_add_extent to handle cases converting a delayed
 * allocation to a real allocation.
 */
STATIC int				/* error */
xfs_bmap_add_extent_delay_real(
	xfs_inode_t		*ip,	/* incore inode pointer */
	xfs_extnum_t		*idx,	/* extent number to update/insert */
	xfs_btree_cur_t		**curp,	/* if *curp is null, not a btree */
	xfs_bmbt_irec_t		*new,	/* new data to add to file extents */
	xfs_filblks_t		*dnew,	/* new delayed-alloc indirect blocks */
	xfs_fsblock_t		*first,	/* pointer to firstblock variable */
	xfs_bmap_free_t		*flist,	/* list of extents to be freed */
	int			*logflagsp); /* inode logging flags */

/*
 * Called by xfs_bmap_add_extent to handle cases converting a hole
 * to a delayed allocation.
 */
STATIC int				/* error */
xfs_bmap_add_extent_hole_delay(
	xfs_inode_t		*ip,	/* incore inode pointer */
	xfs_extnum_t		*idx,	/* extent number to update/insert */
	xfs_bmbt_irec_t		*new,	/* new data to add to file extents */
	int			*logflagsp); /* inode logging flags */

/*
 * Called by xfs_bmap_add_extent to handle cases converting a hole
 * to a real allocation.
 */
STATIC int				/* error */
xfs_bmap_add_extent_hole_real(
	xfs_inode_t		*ip,	/* incore inode pointer */
	xfs_extnum_t		*idx,	/* extent number to update/insert */
	xfs_btree_cur_t		*cur,	/* if null, not a btree */
	xfs_bmbt_irec_t		*new,	/* new data to add to file extents */
	int			*logflagsp, /* inode logging flags */
	int			whichfork); /* data or attr fork */

/*
 * Called by xfs_bmap_add_extent to handle cases converting an unwritten
 * allocation to a real allocation or vice versa.
 */
STATIC int				/* error */
xfs_bmap_add_extent_unwritten_real(
	xfs_inode_t		*ip,	/* incore inode pointer */
	xfs_extnum_t		*idx,	/* extent number to update/insert */
	xfs_btree_cur_t		**curp,	/* if *curp is null, not a btree */
	xfs_bmbt_irec_t		*new,	/* new data to add to file extents */
	int			*logflagsp); /* inode logging flags */

/*
 * xfs_bmap_alloc is called by xfs_bmapi to allocate an extent for a file.
 * It figures out where to ask the underlying allocator to put the new extent.
 */
STATIC int				/* error */
xfs_bmap_alloc(
	xfs_bmalloca_t		*ap);	/* bmap alloc argument struct */

/*
 * Transform a btree format file with only one leaf node, where the
 * extents list will fit in the inode, into an extents format file.
 * Since the file extents are already in-core, all we have to do is
 * give up the space for the btree root and pitch the leaf block.
 */
STATIC int				/* error */
xfs_bmap_btree_to_extents(
	xfs_trans_t		*tp,	/* transaction pointer */
	xfs_inode_t		*ip,	/* incore inode pointer */
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			*logflagsp, /* inode logging flags */
	int			whichfork); /* data or attr fork */

/*
 * Remove the entry "free" from the free item list.  Prev points to the
 * previous entry, unless "free" is the head of the list.
 */
STATIC void
xfs_bmap_del_free(
	xfs_bmap_free_t		*flist,	/* free item list header */
	xfs_bmap_free_item_t	*prev,	/* previous item on list, if any */
	xfs_bmap_free_item_t	*free);	/* list item to be freed */

/*
 * Convert an extents-format file into a btree-format file.
 * The new file will have a root block (in the inode) and a single child block.
 */
STATIC int					/* error */
xfs_bmap_extents_to_btree(
	xfs_trans_t		*tp,		/* transaction pointer */
	xfs_inode_t		*ip,		/* incore inode pointer */
	xfs_fsblock_t		*firstblock,	/* first-block-allocated */
	xfs_bmap_free_t		*flist,		/* blocks freed in xaction */
	xfs_btree_cur_t		**curp,		/* cursor returned to caller */
	int			wasdel,		/* converting a delayed alloc */
	int			*logflagsp,	/* inode logging flags */
	int			whichfork);	/* data or attr fork */

/*
 * Convert a local file to an extents file.
 * This code is sort of bogus, since the file data needs to get
 * logged so it won't be lost.  The bmap-level manipulations are ok, though.
 */
STATIC int				/* error */
xfs_bmap_local_to_extents(
	xfs_trans_t	*tp,		/* transaction pointer */
	xfs_inode_t	*ip,		/* incore inode pointer */
	xfs_fsblock_t	*firstblock,	/* first block allocated in xaction */
	xfs_extlen_t	total,		/* total blocks needed by transaction */
	int		*logflagsp,	/* inode logging flags */
	int		whichfork);	/* data or attr fork */

/*
 * Search the extents list for the inode, for the extent containing bno.
 * If bno lies in a hole, point to the next entry.  If bno lies past eof,
 * *eofp will be set, and *prevp will contain the last entry (null if none).
 * Else, *lastxp will be set to the index of the found
 * entry; *gotp will contain the entry.
 */
STATIC xfs_bmbt_rec_host_t *		/* pointer to found extent entry */
xfs_bmap_search_extents(
	xfs_inode_t	*ip,		/* incore inode pointer */
	xfs_fileoff_t	bno,		/* block number searched for */
	int		whichfork,	/* data or attr fork */
	int		*eofp,		/* out: end of file found */
	xfs_extnum_t	*lastxp,	/* out: last extent index */
	xfs_bmbt_irec_t	*gotp,		/* out: extent entry found */
	xfs_bmbt_irec_t	*prevp);	/* out: previous extent entry found */

/*
 * Check the last inode extent to determine whether this allocation will result
 * in blocks being allocated at the end of the file. When we allocate new data
 * blocks at the end of the file which do not start at the previous data block,
 * we will try to align the new blocks at stripe unit boundaries.
 */
STATIC int				/* error */
xfs_bmap_isaeof(
	xfs_inode_t	*ip,		/* incore inode pointer */
	xfs_fileoff_t   off,		/* file offset in fsblocks */
	int             whichfork,	/* data or attribute fork */
	char		*aeof);		/* return value */

/*
 * Compute the worst-case number of indirect blocks that will be used
 * for ip's delayed extent of length "len".
 */
STATIC xfs_filblks_t
xfs_bmap_worst_indlen(
	xfs_inode_t		*ip,	/* incore inode pointer */
	xfs_filblks_t		len);	/* delayed extent length */

#ifdef DEBUG
/*
 * Perform various validation checks on the values being returned
 * from xfs_bmapi().
 */
STATIC void
xfs_bmap_validate_ret(
	xfs_fileoff_t		bno,
	xfs_filblks_t		len,
	int			flags,
	xfs_bmbt_irec_t		*mval,
	int			nmap,
	int			ret_nmap);
#else
#define	xfs_bmap_validate_ret(bno,len,flags,mval,onmap,nmap)
#endif /* DEBUG */

STATIC int
xfs_bmap_count_tree(
	xfs_mount_t     *mp,
	xfs_trans_t     *tp,
	xfs_ifork_t	*ifp,
	xfs_fsblock_t   blockno,
	int             levelin,
	int		*count);

STATIC void
xfs_bmap_count_leaves(
	xfs_ifork_t		*ifp,
	xfs_extnum_t		idx,
	int			numrecs,
	int			*count);

STATIC void
xfs_bmap_disk_count_leaves(
	struct xfs_mount	*mp,
	struct xfs_btree_block	*block,
	int			numrecs,
	int			*count);

/*
 * Bmap internal routines.
 */

STATIC int				/* error */
xfs_bmbt_lookup_eq(
	struct xfs_btree_cur	*cur,
	xfs_fileoff_t		off,
	xfs_fsblock_t		bno,
	xfs_filblks_t		len,
	int			*stat)	/* success/failure */
{
	cur->bc_rec.b.br_startoff = off;
	cur->bc_rec.b.br_startblock = bno;
	cur->bc_rec.b.br_blockcount = len;
	return xfs_btree_lookup(cur, XFS_LOOKUP_EQ, stat);
}

STATIC int				/* error */
xfs_bmbt_lookup_ge(
	struct xfs_btree_cur	*cur,
	xfs_fileoff_t		off,
	xfs_fsblock_t		bno,
	xfs_filblks_t		len,
	int			*stat)	/* success/failure */
{
	cur->bc_rec.b.br_startoff = off;
	cur->bc_rec.b.br_startblock = bno;
	cur->bc_rec.b.br_blockcount = len;
	return xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat);
}

/*
* Update the record referred to by cur to the value given
 * by [off, bno, len, state].
 * This either works (return 0) or gets an EFSCORRUPTED error.
 */
STATIC int
xfs_bmbt_update(
	struct xfs_btree_cur	*cur,
	xfs_fileoff_t		off,
	xfs_fsblock_t		bno,
	xfs_filblks_t		len,
	xfs_exntst_t		state)
{
	union xfs_btree_rec	rec;

	xfs_bmbt_disk_set_allf(&rec.bmbt, off, bno, len, state);
	return xfs_btree_update(cur, &rec);
}

/*
 * Called from xfs_bmap_add_attrfork to handle btree format files.
 */
STATIC int					/* error */
xfs_bmap_add_attrfork_btree(
	xfs_trans_t		*tp,		/* transaction pointer */
	xfs_inode_t		*ip,		/* incore inode pointer */
	xfs_fsblock_t		*firstblock,	/* first block allocated */
	xfs_bmap_free_t		*flist,		/* blocks to free at commit */
	int			*flags)		/* inode logging flags */
{
	xfs_btree_cur_t		*cur;		/* btree cursor */
	int			error;		/* error return value */
	xfs_mount_t		*mp;		/* file system mount struct */
	int			stat;		/* newroot status */

	mp = ip->i_mount;
	if (ip->i_df.if_broot_bytes <= XFS_IFORK_DSIZE(ip))
		*flags |= XFS_ILOG_DBROOT;
	else {
		cur = xfs_bmbt_init_cursor(mp, tp, ip, XFS_DATA_FORK);
		cur->bc_private.b.flist = flist;
		cur->bc_private.b.firstblock = *firstblock;
		if ((error = xfs_bmbt_lookup_ge(cur, 0, 0, 0, &stat)))
			goto error0;
		/* must be at least one entry */
		XFS_WANT_CORRUPTED_GOTO(stat == 1, error0);
		if ((error = xfs_btree_new_iroot(cur, flags, &stat)))
			goto error0;
		if (stat == 0) {
			xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
			return XFS_ERROR(ENOSPC);
		}
		*firstblock = cur->bc_private.b.firstblock;
		cur->bc_private.b.allocated = 0;
		xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
	}
	return 0;
error0:
	xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
	return error;
}

/*
 * Called from xfs_bmap_add_attrfork to handle extents format files.
 */
STATIC int					/* error */
xfs_bmap_add_attrfork_extents(
	xfs_trans_t		*tp,		/* transaction pointer */
	xfs_inode_t		*ip,		/* incore inode pointer */
	xfs_fsblock_t		*firstblock,	/* first block allocated */
	xfs_bmap_free_t		*flist,		/* blocks to free at commit */
	int			*flags)		/* inode logging flags */
{
	xfs_btree_cur_t		*cur;		/* bmap btree cursor */
	int			error;		/* error return value */

	if (ip->i_d.di_nextents * sizeof(xfs_bmbt_rec_t) <= XFS_IFORK_DSIZE(ip))
		return 0;
	cur = NULL;
	error = xfs_bmap_extents_to_btree(tp, ip, firstblock, flist, &cur, 0,
		flags, XFS_DATA_FORK);
	if (cur) {
		cur->bc_private.b.allocated = 0;
		xfs_btree_del_cursor(cur,
			error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
	}
	return error;
}

/*
 * Called from xfs_bmap_add_attrfork to handle local format files.
 */
STATIC int					/* error */
xfs_bmap_add_attrfork_local(
	xfs_trans_t		*tp,		/* transaction pointer */
	xfs_inode_t		*ip,		/* incore inode pointer */
	xfs_fsblock_t		*firstblock,	/* first block allocated */
	xfs_bmap_free_t		*flist,		/* blocks to free at commit */
	int			*flags)		/* inode logging flags */
{
	xfs_da_args_t		dargs;		/* args for dir/attr code */
	int			error;		/* error return value */
	xfs_mount_t		*mp;		/* mount structure pointer */

	if (ip->i_df.if_bytes <= XFS_IFORK_DSIZE(ip))
		return 0;
	if ((ip->i_d.di_mode & S_IFMT) == S_IFDIR) {
		mp = ip->i_mount;
		memset(&dargs, 0, sizeof(dargs));
		dargs.dp = ip;
		dargs.firstblock = firstblock;
		dargs.flist = flist;
		dargs.total = mp->m_dirblkfsbs;
		dargs.whichfork = XFS_DATA_FORK;
		dargs.trans = tp;
		error = xfs_dir2_sf_to_block(&dargs);
	} else
		error = xfs_bmap_local_to_extents(tp, ip, firstblock, 1, flags,
			XFS_DATA_FORK);
	return error;
}

/*
 * Called by xfs_bmapi to update file extent records and the btree
 * after allocating space (or doing a delayed allocation).
 */
STATIC int				/* error */
xfs_bmap_add_extent(
	xfs_inode_t		*ip,	/* incore inode pointer */
	xfs_extnum_t		*idx,	/* extent number to update/insert */
	xfs_btree_cur_t		**curp,	/* if *curp is null, not a btree */
	xfs_bmbt_irec_t		*new,	/* new data to add to file extents */
	xfs_fsblock_t		*first,	/* pointer to firstblock variable */
	xfs_bmap_free_t		*flist,	/* list of extents to be freed */
	int			*logflagsp, /* inode logging flags */
	int			whichfork) /* data or attr fork */
{
	xfs_btree_cur_t		*cur;	/* btree cursor or null */
	xfs_filblks_t		da_new; /* new count del alloc blocks used */
	xfs_filblks_t		da_old; /* old count del alloc blocks used */
	int			error;	/* error return value */
	xfs_ifork_t		*ifp;	/* inode fork ptr */
	int			logflags; /* returned value */
	xfs_extnum_t		nextents; /* number of extents in file now */

	XFS_STATS_INC(xs_add_exlist);

	cur = *curp;
	ifp = XFS_IFORK_PTR(ip, whichfork);
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	da_old = da_new = 0;
	error = 0;

	ASSERT(*idx >= 0);
	ASSERT(*idx <= nextents);

	/*
	 * This is the first extent added to a new/empty file.
	 * Special case this one, so other routines get to assume there are
	 * already extents in the list.
	 */
	if (nextents == 0) {
		xfs_iext_insert(ip, *idx, 1, new,
				whichfork == XFS_ATTR_FORK ? BMAP_ATTRFORK : 0);

		ASSERT(cur == NULL);

		if (!isnullstartblock(new->br_startblock)) {
			XFS_IFORK_NEXT_SET(ip, whichfork, 1);
			logflags = XFS_ILOG_CORE | xfs_ilog_fext(whichfork);
		} else
			logflags = 0;
	}
	/*
	 * Any kind of new delayed allocation goes here.
	 */
	else if (isnullstartblock(new->br_startblock)) {
		if (cur)
			ASSERT((cur->bc_private.b.flags &
				XFS_BTCUR_BPRV_WASDEL) == 0);
		error = xfs_bmap_add_extent_hole_delay(ip, idx, new,
						       &logflags);
	}
	/*
	 * Real allocation off the end of the file.
	 */
	else if (*idx == nextents) {
		if (cur)
			ASSERT((cur->bc_private.b.flags &
				XFS_BTCUR_BPRV_WASDEL) == 0);
		error = xfs_bmap_add_extent_hole_real(ip, idx, cur, new,
				&logflags, whichfork);
	} else {
		xfs_bmbt_irec_t	prev;	/* old extent at offset idx */

		/*
		 * Get the record referred to by idx.
		 */
		xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *idx), &prev);
		/*
		 * If it's a real allocation record, and the new allocation ends
		 * after the start of the referred to record, then we're filling
		 * in a delayed or unwritten allocation with a real one, or
		 * converting real back to unwritten.
		 */
		if (!isnullstartblock(new->br_startblock) &&
		    new->br_startoff + new->br_blockcount > prev.br_startoff) {
			if (prev.br_state != XFS_EXT_UNWRITTEN &&
			    isnullstartblock(prev.br_startblock)) {
				da_old = startblockval(prev.br_startblock);
				if (cur)
					ASSERT(cur->bc_private.b.flags &
						XFS_BTCUR_BPRV_WASDEL);
				error = xfs_bmap_add_extent_delay_real(ip,
						idx, &cur, new, &da_new,
						first, flist, &logflags);
			} else {
				ASSERT(new->br_state == XFS_EXT_NORM ||
				       new->br_state == XFS_EXT_UNWRITTEN);

				error = xfs_bmap_add_extent_unwritten_real(ip,
						idx, &cur, new, &logflags);
				if (error)
					goto done;
			}
		}
		/*
		 * Otherwise we're filling in a hole with an allocation.
		 */
		else {
			if (cur)
				ASSERT((cur->bc_private.b.flags &
					XFS_BTCUR_BPRV_WASDEL) == 0);
			error = xfs_bmap_add_extent_hole_real(ip, idx, cur,
					new, &logflags, whichfork);
		}
	}

	if (error)
		goto done;
	ASSERT(*curp == cur || *curp == NULL);

	/*
	 * Convert to a btree if necessary.
	 */
	if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS &&
	    XFS_IFORK_NEXTENTS(ip, whichfork) > ifp->if_ext_max) {
		int	tmp_logflags;	/* partial log flag return val */

		ASSERT(cur == NULL);
		error = xfs_bmap_extents_to_btree(ip->i_transp, ip, first,
			flist, &cur, da_old > 0, &tmp_logflags, whichfork);
		logflags |= tmp_logflags;
		if (error)
			goto done;
	}
	/*
	 * Adjust for changes in reserved delayed indirect blocks.
	 * Nothing to do for disk quotas here.
	 */
	if (da_old || da_new) {
		xfs_filblks_t	nblks;

		nblks = da_new;
		if (cur)
			nblks += cur->bc_private.b.allocated;
		ASSERT(nblks <= da_old);
		if (nblks < da_old)
			xfs_icsb_modify_counters(ip->i_mount, XFS_SBS_FDBLOCKS,
				(int64_t)(da_old - nblks), 0);
	}
	/*
	 * Clear out the allocated field, done with it now in any case.
	 */
	if (cur) {
		cur->bc_private.b.allocated = 0;
		*curp = cur;
	}
done:
#ifdef DEBUG
	if (!error)
		xfs_bmap_check_leaf_extents(*curp, ip, whichfork);
#endif
	*logflagsp = logflags;
	return error;
}

/*
 * Called by xfs_bmap_add_extent to handle cases converting a delayed
 * allocation to a real allocation.
 */
STATIC int				/* error */
xfs_bmap_add_extent_delay_real(
	xfs_inode_t		*ip,	/* incore inode pointer */
	xfs_extnum_t		*idx,	/* extent number to update/insert */
	xfs_btree_cur_t		**curp,	/* if *curp is null, not a btree */
	xfs_bmbt_irec_t		*new,	/* new data to add to file extents */
	xfs_filblks_t		*dnew,	/* new delayed-alloc indirect blocks */
	xfs_fsblock_t		*first,	/* pointer to firstblock variable */
	xfs_bmap_free_t		*flist,	/* list of extents to be freed */
	int			*logflagsp) /* inode logging flags */
{
	xfs_btree_cur_t		*cur;	/* btree cursor */
	int			diff;	/* temp value */
	xfs_bmbt_rec_host_t	*ep;	/* extent entry for idx */
	int			error;	/* error return value */
	int			i;	/* temp state */
	xfs_ifork_t		*ifp;	/* inode fork pointer */
	xfs_fileoff_t		new_endoff;	/* end offset of new entry */
	xfs_bmbt_irec_t		r[3];	/* neighbor extent entries */
					/* left is 0, right is 1, prev is 2 */
	int			rval=0;	/* return value (logging flags) */
	int			state = 0;/* state bits, accessed thru macros */
	xfs_filblks_t		temp=0;	/* value for dnew calculations */
	xfs_filblks_t		temp2=0;/* value for dnew calculations */
	int			tmp_rval;	/* partial logging flags */

#define	LEFT		r[0]
#define	RIGHT		r[1]
#define	PREV		r[2]

	/*
	 * Set up a bunch of variables to make the tests simpler.
	 */
	cur = *curp;
	ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
	ep = xfs_iext_get_ext(ifp, *idx);
	xfs_bmbt_get_all(ep, &PREV);
	new_endoff = new->br_startoff + new->br_blockcount;
	ASSERT(PREV.br_startoff <= new->br_startoff);
	ASSERT(PREV.br_startoff + PREV.br_blockcount >= new_endoff);

	/*
	 * Set flags determining what part of the previous delayed allocation
	 * extent is being replaced by a real allocation.
	 */
	if (PREV.br_startoff == new->br_startoff)
		state |= BMAP_LEFT_FILLING;
	if (PREV.br_startoff + PREV.br_blockcount == new_endoff)
		state |= BMAP_RIGHT_FILLING;

	/*
	 * Check and set flags if this segment has a left neighbor.
	 * Don't set contiguous if the combined extent would be too large.
	 */
	if (*idx > 0) {
		state |= BMAP_LEFT_VALID;
		xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *idx - 1), &LEFT);

		if (isnullstartblock(LEFT.br_startblock))
			state |= BMAP_LEFT_DELAY;
	}

	if ((state & BMAP_LEFT_VALID) && !(state & BMAP_LEFT_DELAY) &&
	    LEFT.br_startoff + LEFT.br_blockcount == new->br_startoff &&
	    LEFT.br_startblock + LEFT.br_blockcount == new->br_startblock &&
	    LEFT.br_state == new->br_state &&
	    LEFT.br_blockcount + new->br_blockcount <= MAXEXTLEN)
		state |= BMAP_LEFT_CONTIG;

	/*
	 * Check and set flags if this segment has a right neighbor.
	 * Don't set contiguous if the combined extent would be too large.
	 * Also check for all-three-contiguous being too large.
	 */
	if (*idx < ip->i_df.if_bytes / (uint)sizeof(xfs_bmbt_rec_t) - 1) {
		state |= BMAP_RIGHT_VALID;
		xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *idx + 1), &RIGHT);

		if (isnullstartblock(RIGHT.br_startblock))
			state |= BMAP_RIGHT_DELAY;
	}

	if ((state & BMAP_RIGHT_VALID) && !(state & BMAP_RIGHT_DELAY) &&
	    new_endoff == RIGHT.br_startoff &&
	    new->br_startblock + new->br_blockcount == RIGHT.br_startblock &&
	    new->br_state == RIGHT.br_state &&
	    new->br_blockcount + RIGHT.br_blockcount <= MAXEXTLEN &&
	    ((state & (BMAP_LEFT_CONTIG | BMAP_LEFT_FILLING |
		       BMAP_RIGHT_FILLING)) !=
		      (BMAP_LEFT_CONTIG | BMAP_LEFT_FILLING |
		       BMAP_RIGHT_FILLING) ||
	     LEFT.br_blockcount + new->br_blockcount + RIGHT.br_blockcount
			<= MAXEXTLEN))
		state |= BMAP_RIGHT_CONTIG;

	error = 0;
	/*
	 * Switch out based on the FILLING and CONTIG state bits.
	 */
	switch (state & (BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG |
			 BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG)) {
	case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG |
	     BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
		/*
		 * Filling in all of a previously delayed allocation extent.
		 * The left and right neighbors are both contiguous with new.
		 */
		--*idx;
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, *idx),
			LEFT.br_blockcount + PREV.br_blockcount +
			RIGHT.br_blockcount);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		xfs_iext_remove(ip, *idx + 1, 2, state);
		ip->i_d.di_nextents--;
		if (cur == NULL)
			rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
		else {
			rval = XFS_ILOG_CORE;
			if ((error = xfs_bmbt_lookup_eq(cur, RIGHT.br_startoff,
					RIGHT.br_startblock,
					RIGHT.br_blockcount, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_btree_delete(cur, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_btree_decrement(cur, 0, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur, LEFT.br_startoff,
					LEFT.br_startblock,
					LEFT.br_blockcount +
					PREV.br_blockcount +
					RIGHT.br_blockcount, LEFT.br_state)))
				goto done;
		}
		*dnew = 0;
		break;

	case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING | BMAP_LEFT_CONTIG:
		/*
		 * Filling in all of a previously delayed allocation extent.
		 * The left neighbor is contiguous, the right is not.
		 */
		--*idx;

		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, *idx),
			LEFT.br_blockcount + PREV.br_blockcount);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		xfs_iext_remove(ip, *idx + 1, 1, state);
		if (cur == NULL)
			rval = XFS_ILOG_DEXT;
		else {
			rval = 0;
			if ((error = xfs_bmbt_lookup_eq(cur, LEFT.br_startoff,
					LEFT.br_startblock, LEFT.br_blockcount,
					&i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur, LEFT.br_startoff,
					LEFT.br_startblock,
					LEFT.br_blockcount +
					PREV.br_blockcount, LEFT.br_state)))
				goto done;
		}
		*dnew = 0;
		break;

	case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
		/*
		 * Filling in all of a previously delayed allocation extent.
		 * The right neighbor is contiguous, the left is not.
		 */
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_startblock(ep, new->br_startblock);
		xfs_bmbt_set_blockcount(ep,
			PREV.br_blockcount + RIGHT.br_blockcount);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		xfs_iext_remove(ip, *idx + 1, 1, state);
		if (cur == NULL)
			rval = XFS_ILOG_DEXT;
		else {
			rval = 0;
			if ((error = xfs_bmbt_lookup_eq(cur, RIGHT.br_startoff,
					RIGHT.br_startblock,
					RIGHT.br_blockcount, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur, PREV.br_startoff,
					new->br_startblock,
					PREV.br_blockcount +
					RIGHT.br_blockcount, PREV.br_state)))
				goto done;
		}

		*dnew = 0;
		break;

	case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING:
		/*
		 * Filling in all of a previously delayed allocation extent.
		 * Neither the left nor right neighbors are contiguous with
		 * the new one.
		 */
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_startblock(ep, new->br_startblock);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		ip->i_d.di_nextents++;
		if (cur == NULL)
			rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
		else {
			rval = XFS_ILOG_CORE;
			if ((error = xfs_bmbt_lookup_eq(cur, new->br_startoff,
					new->br_startblock, new->br_blockcount,
					&i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 0, done);
			cur->bc_rec.b.br_state = XFS_EXT_NORM;
			if ((error = xfs_btree_insert(cur, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
		}

		*dnew = 0;
		break;

	case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG:
		/*
		 * Filling in the first part of a previous delayed allocation.
		 * The left neighbor is contiguous.
		 */
		trace_xfs_bmap_pre_update(ip, *idx - 1, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, *idx - 1),
			LEFT.br_blockcount + new->br_blockcount);
		xfs_bmbt_set_startoff(ep,
			PREV.br_startoff + new->br_blockcount);
		trace_xfs_bmap_post_update(ip, *idx - 1, state, _THIS_IP_);

		temp = PREV.br_blockcount - new->br_blockcount;
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(ep, temp);
		if (cur == NULL)
			rval = XFS_ILOG_DEXT;
		else {
			rval = 0;
			if ((error = xfs_bmbt_lookup_eq(cur, LEFT.br_startoff,
					LEFT.br_startblock, LEFT.br_blockcount,
					&i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur, LEFT.br_startoff,
					LEFT.br_startblock,
					LEFT.br_blockcount +
					new->br_blockcount,
					LEFT.br_state)))
				goto done;
		}
		temp = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp),
			startblockval(PREV.br_startblock));
		xfs_bmbt_set_startblock(ep, nullstartblock((int)temp));
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		--*idx;
		*dnew = temp;
		break;

	case BMAP_LEFT_FILLING:
		/*
		 * Filling in the first part of a previous delayed allocation.
		 * The left neighbor is not contiguous.
		 */
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_startoff(ep, new_endoff);
		temp = PREV.br_blockcount - new->br_blockcount;
		xfs_bmbt_set_blockcount(ep, temp);
		xfs_iext_insert(ip, *idx, 1, new, state);
		ip->i_d.di_nextents++;
		if (cur == NULL)
			rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
		else {
			rval = XFS_ILOG_CORE;
			if ((error = xfs_bmbt_lookup_eq(cur, new->br_startoff,
					new->br_startblock, new->br_blockcount,
					&i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 0, done);
			cur->bc_rec.b.br_state = XFS_EXT_NORM;
			if ((error = xfs_btree_insert(cur, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
		}
		if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
		    ip->i_d.di_nextents > ip->i_df.if_ext_max) {
			error = xfs_bmap_extents_to_btree(ip->i_transp, ip,
					first, flist, &cur, 1, &tmp_rval,
					XFS_DATA_FORK);
			rval |= tmp_rval;
			if (error)
				goto done;
		}
		temp = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp),
			startblockval(PREV.br_startblock) -
			(cur ? cur->bc_private.b.allocated : 0));
		ep = xfs_iext_get_ext(ifp, *idx + 1);
		xfs_bmbt_set_startblock(ep, nullstartblock((int)temp));
		trace_xfs_bmap_post_update(ip, *idx + 1, state, _THIS_IP_);

		*dnew = temp;
		break;

	case BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
		/*
		 * Filling in the last part of a previous delayed allocation.
		 * The right neighbor is contiguous with the new allocation.
		 */
		temp = PREV.br_blockcount - new->br_blockcount;
		trace_xfs_bmap_pre_update(ip, *idx + 1, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(ep, temp);
		xfs_bmbt_set_allf(xfs_iext_get_ext(ifp, *idx + 1),
			new->br_startoff, new->br_startblock,
			new->br_blockcount + RIGHT.br_blockcount,
			RIGHT.br_state);
		trace_xfs_bmap_post_update(ip, *idx + 1, state, _THIS_IP_);
		if (cur == NULL)
			rval = XFS_ILOG_DEXT;
		else {
			rval = 0;
			if ((error = xfs_bmbt_lookup_eq(cur, RIGHT.br_startoff,
					RIGHT.br_startblock,
					RIGHT.br_blockcount, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur, new->br_startoff,
					new->br_startblock,
					new->br_blockcount +
					RIGHT.br_blockcount,
					RIGHT.br_state)))
				goto done;
		}

		temp = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp),
			startblockval(PREV.br_startblock));
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_startblock(ep, nullstartblock((int)temp));
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		++*idx;
		*dnew = temp;
		break;

	case BMAP_RIGHT_FILLING:
		/*
		 * Filling in the last part of a previous delayed allocation.
		 * The right neighbor is not contiguous.
		 */
		temp = PREV.br_blockcount - new->br_blockcount;
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(ep, temp);
		xfs_iext_insert(ip, *idx + 1, 1, new, state);
		ip->i_d.di_nextents++;
		if (cur == NULL)
			rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
		else {
			rval = XFS_ILOG_CORE;
			if ((error = xfs_bmbt_lookup_eq(cur, new->br_startoff,
					new->br_startblock, new->br_blockcount,
					&i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 0, done);
			cur->bc_rec.b.br_state = XFS_EXT_NORM;
			if ((error = xfs_btree_insert(cur, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
		}
		if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
		    ip->i_d.di_nextents > ip->i_df.if_ext_max) {
			error = xfs_bmap_extents_to_btree(ip->i_transp, ip,
				first, flist, &cur, 1, &tmp_rval,
				XFS_DATA_FORK);
			rval |= tmp_rval;
			if (error)
				goto done;
		}
		temp = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp),
			startblockval(PREV.br_startblock) -
			(cur ? cur->bc_private.b.allocated : 0));
		ep = xfs_iext_get_ext(ifp, *idx);
		xfs_bmbt_set_startblock(ep, nullstartblock((int)temp));
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		++*idx;
		*dnew = temp;
		break;

	case 0:
		/*
		 * Filling in the middle part of a previous delayed allocation.
		 * Contiguity is impossible here.
		 * This case is avoided almost all the time.
		 *
		 * We start with a delayed allocation:
		 *
		 * +ddddddddddddddddddddddddddddddddddddddddddddddddddddddd+
		 *  PREV @ idx
		 *
	         * and we are allocating:
		 *                     +rrrrrrrrrrrrrrrrr+
		 *			      new
		 *
		 * and we set it up for insertion as:
		 * +ddddddddddddddddddd+rrrrrrrrrrrrrrrrr+ddddddddddddddddd+
		 *                            new
		 *  PREV @ idx          LEFT              RIGHT
		 *                      inserted at idx + 1
		 */
		temp = new->br_startoff - PREV.br_startoff;
		temp2 = PREV.br_startoff + PREV.br_blockcount - new_endoff;
		trace_xfs_bmap_pre_update(ip, *idx, 0, _THIS_IP_);
		xfs_bmbt_set_blockcount(ep, temp);	/* truncate PREV */
		LEFT = *new;
		RIGHT.br_state = PREV.br_state;
		RIGHT.br_startblock = nullstartblock(
				(int)xfs_bmap_worst_indlen(ip, temp2));
		RIGHT.br_startoff = new_endoff;
		RIGHT.br_blockcount = temp2;
		/* insert LEFT (r[0]) and RIGHT (r[1]) at the same time */
		xfs_iext_insert(ip, *idx + 1, 2, &LEFT, state);
		ip->i_d.di_nextents++;
		if (cur == NULL)
			rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
		else {
			rval = XFS_ILOG_CORE;
			if ((error = xfs_bmbt_lookup_eq(cur, new->br_startoff,
					new->br_startblock, new->br_blockcount,
					&i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 0, done);
			cur->bc_rec.b.br_state = XFS_EXT_NORM;
			if ((error = xfs_btree_insert(cur, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
		}
		if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
		    ip->i_d.di_nextents > ip->i_df.if_ext_max) {
			error = xfs_bmap_extents_to_btree(ip->i_transp, ip,
					first, flist, &cur, 1, &tmp_rval,
					XFS_DATA_FORK);
			rval |= tmp_rval;
			if (error)
				goto done;
		}
		temp = xfs_bmap_worst_indlen(ip, temp);
		temp2 = xfs_bmap_worst_indlen(ip, temp2);
		diff = (int)(temp + temp2 - startblockval(PREV.br_startblock) -
			(cur ? cur->bc_private.b.allocated : 0));
		if (diff > 0 &&
		    xfs_icsb_modify_counters(ip->i_mount, XFS_SBS_FDBLOCKS,
					     -((int64_t)diff), 0)) {
			/*
			 * Ick gross gag me with a spoon.
			 */
			ASSERT(0);	/* want to see if this ever happens! */
			while (diff > 0) {
				if (temp) {
					temp--;
					diff--;
					if (!diff ||
					    !xfs_icsb_modify_counters(ip->i_mount,
						    XFS_SBS_FDBLOCKS,
						    -((int64_t)diff), 0))
						break;
				}
				if (temp2) {
					temp2--;
					diff--;
					if (!diff ||
					    !xfs_icsb_modify_counters(ip->i_mount,
						    XFS_SBS_FDBLOCKS,
						    -((int64_t)diff), 0))
						break;
				}
			}
		}
		ep = xfs_iext_get_ext(ifp, *idx);
		xfs_bmbt_set_startblock(ep, nullstartblock((int)temp));
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
		trace_xfs_bmap_pre_update(ip, *idx + 2, state, _THIS_IP_);
		xfs_bmbt_set_startblock(xfs_iext_get_ext(ifp, *idx + 2),
			nullstartblock((int)temp2));
		trace_xfs_bmap_post_update(ip, *idx + 2, state, _THIS_IP_);

		++*idx;
		*dnew = temp + temp2;
		break;

	case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG | BMAP_RIGHT_CONTIG:
	case BMAP_RIGHT_FILLING | BMAP_LEFT_CONTIG | BMAP_RIGHT_CONTIG:
	case BMAP_LEFT_FILLING | BMAP_RIGHT_CONTIG:
	case BMAP_RIGHT_FILLING | BMAP_LEFT_CONTIG:
	case BMAP_LEFT_CONTIG | BMAP_RIGHT_CONTIG:
	case BMAP_LEFT_CONTIG:
	case BMAP_RIGHT_CONTIG:
		/*
		 * These cases are all impossible.
		 */
		ASSERT(0);
	}
	*curp = cur;
done:
	*logflagsp = rval;
	return error;
#undef	LEFT
#undef	RIGHT
#undef	PREV
}

/*
 * Called by xfs_bmap_add_extent to handle cases converting an unwritten
 * allocation to a real allocation or vice versa.
 */
STATIC int				/* error */
xfs_bmap_add_extent_unwritten_real(
	xfs_inode_t		*ip,	/* incore inode pointer */
	xfs_extnum_t		*idx,	/* extent number to update/insert */
	xfs_btree_cur_t		**curp,	/* if *curp is null, not a btree */
	xfs_bmbt_irec_t		*new,	/* new data to add to file extents */
	int			*logflagsp) /* inode logging flags */
{
	xfs_btree_cur_t		*cur;	/* btree cursor */
	xfs_bmbt_rec_host_t	*ep;	/* extent entry for idx */
	int			error;	/* error return value */
	int			i;	/* temp state */
	xfs_ifork_t		*ifp;	/* inode fork pointer */
	xfs_fileoff_t		new_endoff;	/* end offset of new entry */
	xfs_exntst_t		newext;	/* new extent state */
	xfs_exntst_t		oldext;	/* old extent state */
	xfs_bmbt_irec_t		r[3];	/* neighbor extent entries */
					/* left is 0, right is 1, prev is 2 */
	int			rval=0;	/* return value (logging flags) */
	int			state = 0;/* state bits, accessed thru macros */

#define	LEFT		r[0]
#define	RIGHT		r[1]
#define	PREV		r[2]
	/*
	 * Set up a bunch of variables to make the tests simpler.
	 */
	error = 0;
	cur = *curp;
	ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
	ep = xfs_iext_get_ext(ifp, *idx);
	xfs_bmbt_get_all(ep, &PREV);
	newext = new->br_state;
	oldext = (newext == XFS_EXT_UNWRITTEN) ?
		XFS_EXT_NORM : XFS_EXT_UNWRITTEN;
	ASSERT(PREV.br_state == oldext);
	new_endoff = new->br_startoff + new->br_blockcount;
	ASSERT(PREV.br_startoff <= new->br_startoff);
	ASSERT(PREV.br_startoff + PREV.br_blockcount >= new_endoff);

	/*
	 * Set flags determining what part of the previous oldext allocation
	 * extent is being replaced by a newext allocation.
	 */
	if (PREV.br_startoff == new->br_startoff)
		state |= BMAP_LEFT_FILLING;
	if (PREV.br_startoff + PREV.br_blockcount == new_endoff)
		state |= BMAP_RIGHT_FILLING;

	/*
	 * Check and set flags if this segment has a left neighbor.
	 * Don't set contiguous if the combined extent would be too large.
	 */
	if (*idx > 0) {
		state |= BMAP_LEFT_VALID;
		xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *idx - 1), &LEFT);

		if (isnullstartblock(LEFT.br_startblock))
			state |= BMAP_LEFT_DELAY;
	}

	if ((state & BMAP_LEFT_VALID) && !(state & BMAP_LEFT_DELAY) &&
	    LEFT.br_startoff + LEFT.br_blockcount == new->br_startoff &&
	    LEFT.br_startblock + LEFT.br_blockcount == new->br_startblock &&
	    LEFT.br_state == newext &&
	    LEFT.br_blockcount + new->br_blockcount <= MAXEXTLEN)
		state |= BMAP_LEFT_CONTIG;

	/*
	 * Check and set flags if this segment has a right neighbor.
	 * Don't set contiguous if the combined extent would be too large.
	 * Also check for all-three-contiguous being too large.
	 */
	if (*idx < ip->i_df.if_bytes / (uint)sizeof(xfs_bmbt_rec_t) - 1) {
		state |= BMAP_RIGHT_VALID;
		xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *idx + 1), &RIGHT);
		if (isnullstartblock(RIGHT.br_startblock))
			state |= BMAP_RIGHT_DELAY;
	}

	if ((state & BMAP_RIGHT_VALID) && !(state & BMAP_RIGHT_DELAY) &&
	    new_endoff == RIGHT.br_startoff &&
	    new->br_startblock + new->br_blockcount == RIGHT.br_startblock &&
	    newext == RIGHT.br_state &&
	    new->br_blockcount + RIGHT.br_blockcount <= MAXEXTLEN &&
	    ((state & (BMAP_LEFT_CONTIG | BMAP_LEFT_FILLING |
		       BMAP_RIGHT_FILLING)) !=
		      (BMAP_LEFT_CONTIG | BMAP_LEFT_FILLING |
		       BMAP_RIGHT_FILLING) ||
	     LEFT.br_blockcount + new->br_blockcount + RIGHT.br_blockcount
			<= MAXEXTLEN))
		state |= BMAP_RIGHT_CONTIG;

	/*
	 * Switch out based on the FILLING and CONTIG state bits.
	 */
	switch (state & (BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG |
			 BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG)) {
	case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG |
	     BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
		/*
		 * Setting all of a previous oldext extent to newext.
		 * The left and right neighbors are both contiguous with new.
		 */
		--*idx;

		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, *idx),
			LEFT.br_blockcount + PREV.br_blockcount +
			RIGHT.br_blockcount);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		xfs_iext_remove(ip, *idx + 1, 2, state);
		ip->i_d.di_nextents -= 2;
		if (cur == NULL)
			rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
		else {
			rval = XFS_ILOG_CORE;
			if ((error = xfs_bmbt_lookup_eq(cur, RIGHT.br_startoff,
					RIGHT.br_startblock,
					RIGHT.br_blockcount, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_btree_delete(cur, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_btree_decrement(cur, 0, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_btree_delete(cur, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_btree_decrement(cur, 0, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur, LEFT.br_startoff,
				LEFT.br_startblock,
				LEFT.br_blockcount + PREV.br_blockcount +
				RIGHT.br_blockcount, LEFT.br_state)))
				goto done;
		}
		break;

	case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING | BMAP_LEFT_CONTIG:
		/*
		 * Setting all of a previous oldext extent to newext.
		 * The left neighbor is contiguous, the right is not.
		 */
		--*idx;

		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, *idx),
			LEFT.br_blockcount + PREV.br_blockcount);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		xfs_iext_remove(ip, *idx + 1, 1, state);
		ip->i_d.di_nextents--;
		if (cur == NULL)
			rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
		else {
			rval = XFS_ILOG_CORE;
			if ((error = xfs_bmbt_lookup_eq(cur, PREV.br_startoff,
					PREV.br_startblock, PREV.br_blockcount,
					&i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_btree_delete(cur, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_btree_decrement(cur, 0, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur, LEFT.br_startoff,
				LEFT.br_startblock,
				LEFT.br_blockcount + PREV.br_blockcount,
				LEFT.br_state)))
				goto done;
		}
		break;

	case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
		/*
		 * Setting all of a previous oldext extent to newext.
		 * The right neighbor is contiguous, the left is not.
		 */
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(ep,
			PREV.br_blockcount + RIGHT.br_blockcount);
		xfs_bmbt_set_state(ep, newext);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
		xfs_iext_remove(ip, *idx + 1, 1, state);
		ip->i_d.di_nextents--;
		if (cur == NULL)
			rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
		else {
			rval = XFS_ILOG_CORE;
			if ((error = xfs_bmbt_lookup_eq(cur, RIGHT.br_startoff,
					RIGHT.br_startblock,
					RIGHT.br_blockcount, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_btree_delete(cur, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_btree_decrement(cur, 0, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur, new->br_startoff,
				new->br_startblock,
				new->br_blockcount + RIGHT.br_blockcount,
				newext)))
				goto done;
		}
		break;

	case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING:
		/*
		 * Setting all of a previous oldext extent to newext.
		 * Neither the left nor right neighbors are contiguous with
		 * the new one.
		 */
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_state(ep, newext);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		if (cur == NULL)
			rval = XFS_ILOG_DEXT;
		else {
			rval = 0;
			if ((error = xfs_bmbt_lookup_eq(cur, new->br_startoff,
					new->br_startblock, new->br_blockcount,
					&i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur, new->br_startoff,
				new->br_startblock, new->br_blockcount,
				newext)))
				goto done;
		}
		break;

	case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG:
		/*
		 * Setting the first part of a previous oldext extent to newext.
		 * The left neighbor is contiguous.
		 */
		trace_xfs_bmap_pre_update(ip, *idx - 1, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, *idx - 1),
			LEFT.br_blockcount + new->br_blockcount);
		xfs_bmbt_set_startoff(ep,
			PREV.br_startoff + new->br_blockcount);
		trace_xfs_bmap_post_update(ip, *idx - 1, state, _THIS_IP_);

		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_startblock(ep,
			new->br_startblock + new->br_blockcount);
		xfs_bmbt_set_blockcount(ep,
			PREV.br_blockcount - new->br_blockcount);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		--*idx;

		if (cur == NULL)
			rval = XFS_ILOG_DEXT;
		else {
			rval = 0;
			if ((error = xfs_bmbt_lookup_eq(cur, PREV.br_startoff,
					PREV.br_startblock, PREV.br_blockcount,
					&i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur,
				PREV.br_startoff + new->br_blockcount,
				PREV.br_startblock + new->br_blockcount,
				PREV.br_blockcount - new->br_blockcount,
				oldext)))
				goto done;
			if ((error = xfs_btree_decrement(cur, 0, &i)))
				goto done;
			if (xfs_bmbt_update(cur, LEFT.br_startoff,
				LEFT.br_startblock,
				LEFT.br_blockcount + new->br_blockcount,
				LEFT.br_state))
				goto done;
		}
		break;

	case BMAP_LEFT_FILLING:
		/*
		 * Setting the first part of a previous oldext extent to newext.
		 * The left neighbor is not contiguous.
		 */
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		ASSERT(ep && xfs_bmbt_get_state(ep) == oldext);
		xfs_bmbt_set_startoff(ep, new_endoff);
		xfs_bmbt_set_blockcount(ep,
			PREV.br_blockcount - new->br_blockcount);
		xfs_bmbt_set_startblock(ep,
			new->br_startblock + new->br_blockcount);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		xfs_iext_insert(ip, *idx, 1, new, state);
		ip->i_d.di_nextents++;
		if (cur == NULL)
			rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
		else {
			rval = XFS_ILOG_CORE;
			if ((error = xfs_bmbt_lookup_eq(cur, PREV.br_startoff,
					PREV.br_startblock, PREV.br_blockcount,
					&i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur,
				PREV.br_startoff + new->br_blockcount,
				PREV.br_startblock + new->br_blockcount,
				PREV.br_blockcount - new->br_blockcount,
				oldext)))
				goto done;
			cur->bc_rec.b = *new;
			if ((error = xfs_btree_insert(cur, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
		}
		break;

	case BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG:
		/*
		 * Setting the last part of a previous oldext extent to newext.
		 * The right neighbor is contiguous with the new allocation.
		 */
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(ep,
			PREV.br_blockcount - new->br_blockcount);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		++*idx;

		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_allf(xfs_iext_get_ext(ifp, *idx),
			new->br_startoff, new->br_startblock,
			new->br_blockcount + RIGHT.br_blockcount, newext);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		if (cur == NULL)
			rval = XFS_ILOG_DEXT;
		else {
			rval = 0;
			if ((error = xfs_bmbt_lookup_eq(cur, PREV.br_startoff,
					PREV.br_startblock,
					PREV.br_blockcount, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur, PREV.br_startoff,
				PREV.br_startblock,
				PREV.br_blockcount - new->br_blockcount,
				oldext)))
				goto done;
			if ((error = xfs_btree_increment(cur, 0, &i)))
				goto done;
			if ((error = xfs_bmbt_update(cur, new->br_startoff,
				new->br_startblock,
				new->br_blockcount + RIGHT.br_blockcount,
				newext)))
				goto done;
		}
		break;

	case BMAP_RIGHT_FILLING:
		/*
		 * Setting the last part of a previous oldext extent to newext.
		 * The right neighbor is not contiguous.
		 */
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(ep,
			PREV.br_blockcount - new->br_blockcount);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		++*idx;
		xfs_iext_insert(ip, *idx, 1, new, state);

		ip->i_d.di_nextents++;
		if (cur == NULL)
			rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
		else {
			rval = XFS_ILOG_CORE;
			if ((error = xfs_bmbt_lookup_eq(cur, PREV.br_startoff,
					PREV.br_startblock, PREV.br_blockcount,
					&i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur, PREV.br_startoff,
				PREV.br_startblock,
				PREV.br_blockcount - new->br_blockcount,
				oldext)))
				goto done;
			if ((error = xfs_bmbt_lookup_eq(cur, new->br_startoff,
					new->br_startblock, new->br_blockcount,
					&i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 0, done);
			cur->bc_rec.b.br_state = XFS_EXT_NORM;
			if ((error = xfs_btree_insert(cur, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
		}
		break;

	case 0:
		/*
		 * Setting the middle part of a previous oldext extent to
		 * newext.  Contiguity is impossible here.
		 * One extent becomes three extents.
		 */
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(ep,
			new->br_startoff - PREV.br_startoff);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		r[0] = *new;
		r[1].br_startoff = new_endoff;
		r[1].br_blockcount =
			PREV.br_startoff + PREV.br_blockcount - new_endoff;
		r[1].br_startblock = new->br_startblock + new->br_blockcount;
		r[1].br_state = oldext;

		++*idx;
		xfs_iext_insert(ip, *idx, 2, &r[0], state);

		ip->i_d.di_nextents += 2;
		if (cur == NULL)
			rval = XFS_ILOG_CORE | XFS_ILOG_DEXT;
		else {
			rval = XFS_ILOG_CORE;
			if ((error = xfs_bmbt_lookup_eq(cur, PREV.br_startoff,
					PREV.br_startblock, PREV.br_blockcount,
					&i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			/* new right extent - oldext */
			if ((error = xfs_bmbt_update(cur, r[1].br_startoff,
				r[1].br_startblock, r[1].br_blockcount,
				r[1].br_state)))
				goto done;
			/* new left extent - oldext */
			cur->bc_rec.b = PREV;
			cur->bc_rec.b.br_blockcount =
				new->br_startoff - PREV.br_startoff;
			if ((error = xfs_btree_insert(cur, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			/*
			 * Reset the cursor to the position of the new extent
			 * we are about to insert as we can't trust it after
			 * the previous insert.
			 */
			if ((error = xfs_bmbt_lookup_eq(cur, new->br_startoff,
					new->br_startblock, new->br_blockcount,
					&i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 0, done);
			/* new middle extent - newext */
			cur->bc_rec.b.br_state = new->br_state;
			if ((error = xfs_btree_insert(cur, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
		}
		break;

	case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG | BMAP_RIGHT_CONTIG:
	case BMAP_RIGHT_FILLING | BMAP_LEFT_CONTIG | BMAP_RIGHT_CONTIG:
	case BMAP_LEFT_FILLING | BMAP_RIGHT_CONTIG:
	case BMAP_RIGHT_FILLING | BMAP_LEFT_CONTIG:
	case BMAP_LEFT_CONTIG | BMAP_RIGHT_CONTIG:
	case BMAP_LEFT_CONTIG:
	case BMAP_RIGHT_CONTIG:
		/*
		 * These cases are all impossible.
		 */
		ASSERT(0);
	}
	*curp = cur;
done:
	*logflagsp = rval;
	return error;
#undef	LEFT
#undef	RIGHT
#undef	PREV
}

/*
 * Called by xfs_bmap_add_extent to handle cases converting a hole
 * to a delayed allocation.
 */
/*ARGSUSED*/
STATIC int				/* error */
xfs_bmap_add_extent_hole_delay(
	xfs_inode_t		*ip,	/* incore inode pointer */
	xfs_extnum_t		*idx,	/* extent number to update/insert */
	xfs_bmbt_irec_t		*new,	/* new data to add to file extents */
	int			*logflagsp) /* inode logging flags */
{
	xfs_ifork_t		*ifp;	/* inode fork pointer */
	xfs_bmbt_irec_t		left;	/* left neighbor extent entry */
	xfs_filblks_t		newlen=0;	/* new indirect size */
	xfs_filblks_t		oldlen=0;	/* old indirect size */
	xfs_bmbt_irec_t		right;	/* right neighbor extent entry */
	int			state;  /* state bits, accessed thru macros */
	xfs_filblks_t		temp=0;	/* temp for indirect calculations */

	ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
	state = 0;
	ASSERT(isnullstartblock(new->br_startblock));

	/*
	 * Check and set flags if this segment has a left neighbor
	 */
	if (*idx > 0) {
		state |= BMAP_LEFT_VALID;
		xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *idx - 1), &left);

		if (isnullstartblock(left.br_startblock))
			state |= BMAP_LEFT_DELAY;
	}

	/*
	 * Check and set flags if the current (right) segment exists.
	 * If it doesn't exist, we're converting the hole at end-of-file.
	 */
	if (*idx < ip->i_df.if_bytes / (uint)sizeof(xfs_bmbt_rec_t)) {
		state |= BMAP_RIGHT_VALID;
		xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *idx), &right);

		if (isnullstartblock(right.br_startblock))
			state |= BMAP_RIGHT_DELAY;
	}

	/*
	 * Set contiguity flags on the left and right neighbors.
	 * Don't let extents get too large, even if the pieces are contiguous.
	 */
	if ((state & BMAP_LEFT_VALID) && (state & BMAP_LEFT_DELAY) &&
	    left.br_startoff + left.br_blockcount == new->br_startoff &&
	    left.br_blockcount + new->br_blockcount <= MAXEXTLEN)
		state |= BMAP_LEFT_CONTIG;

	if ((state & BMAP_RIGHT_VALID) && (state & BMAP_RIGHT_DELAY) &&
	    new->br_startoff + new->br_blockcount == right.br_startoff &&
	    new->br_blockcount + right.br_blockcount <= MAXEXTLEN &&
	    (!(state & BMAP_LEFT_CONTIG) ||
	     (left.br_blockcount + new->br_blockcount +
	      right.br_blockcount <= MAXEXTLEN)))
		state |= BMAP_RIGHT_CONTIG;

	/*
	 * Switch out based on the contiguity flags.
	 */
	switch (state & (BMAP_LEFT_CONTIG | BMAP_RIGHT_CONTIG)) {
	case BMAP_LEFT_CONTIG | BMAP_RIGHT_CONTIG:
		/*
		 * New allocation is contiguous with delayed allocations
		 * on the left and on the right.
		 * Merge all three into a single extent record.
		 */
		--*idx;
		temp = left.br_blockcount + new->br_blockcount +
			right.br_blockcount;

		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, *idx), temp);
		oldlen = startblockval(left.br_startblock) +
			startblockval(new->br_startblock) +
			startblockval(right.br_startblock);
		newlen = xfs_bmap_worst_indlen(ip, temp);
		xfs_bmbt_set_startblock(xfs_iext_get_ext(ifp, *idx),
			nullstartblock((int)newlen));
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		xfs_iext_remove(ip, *idx + 1, 1, state);
		break;

	case BMAP_LEFT_CONTIG:
		/*
		 * New allocation is contiguous with a delayed allocation
		 * on the left.
		 * Merge the new allocation with the left neighbor.
		 */
		--*idx;
		temp = left.br_blockcount + new->br_blockcount;

		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, *idx), temp);
		oldlen = startblockval(left.br_startblock) +
			startblockval(new->br_startblock);
		newlen = xfs_bmap_worst_indlen(ip, temp);
		xfs_bmbt_set_startblock(xfs_iext_get_ext(ifp, *idx),
			nullstartblock((int)newlen));
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
		break;

	case BMAP_RIGHT_CONTIG:
		/*
		 * New allocation is contiguous with a delayed allocation
		 * on the right.
		 * Merge the new allocation with the right neighbor.
		 */
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		temp = new->br_blockcount + right.br_blockcount;
		oldlen = startblockval(new->br_startblock) +
			startblockval(right.br_startblock);
		newlen = xfs_bmap_worst_indlen(ip, temp);
		xfs_bmbt_set_allf(xfs_iext_get_ext(ifp, *idx),
			new->br_startoff,
			nullstartblock((int)newlen), temp, right.br_state);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
		break;

	case 0:
		/*
		 * New allocation is not contiguous with another
		 * delayed allocation.
		 * Insert a new entry.
		 */
		oldlen = newlen = 0;
		xfs_iext_insert(ip, *idx, 1, new, state);
		break;
	}
	if (oldlen != newlen) {
		ASSERT(oldlen > newlen);
		xfs_icsb_modify_counters(ip->i_mount, XFS_SBS_FDBLOCKS,
			(int64_t)(oldlen - newlen), 0);
		/*
		 * Nothing to do for disk quota accounting here.
		 */
	}
	*logflagsp = 0;
	return 0;
}

/*
 * Called by xfs_bmap_add_extent to handle cases converting a hole
 * to a real allocation.
 */
STATIC int				/* error */
xfs_bmap_add_extent_hole_real(
	xfs_inode_t		*ip,	/* incore inode pointer */
	xfs_extnum_t		*idx,	/* extent number to update/insert */
	xfs_btree_cur_t		*cur,	/* if null, not a btree */
	xfs_bmbt_irec_t		*new,	/* new data to add to file extents */
	int			*logflagsp, /* inode logging flags */
	int			whichfork) /* data or attr fork */
{
	int			error;	/* error return value */
	int			i;	/* temp state */
	xfs_ifork_t		*ifp;	/* inode fork pointer */
	xfs_bmbt_irec_t		left;	/* left neighbor extent entry */
	xfs_bmbt_irec_t		right;	/* right neighbor extent entry */
	int			rval=0;	/* return value (logging flags) */
	int			state;	/* state bits, accessed thru macros */

	ifp = XFS_IFORK_PTR(ip, whichfork);
	ASSERT(*idx <= ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t));
	state = 0;

	if (whichfork == XFS_ATTR_FORK)
		state |= BMAP_ATTRFORK;

	/*
	 * Check and set flags if this segment has a left neighbor.
	 */
	if (*idx > 0) {
		state |= BMAP_LEFT_VALID;
		xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *idx - 1), &left);
		if (isnullstartblock(left.br_startblock))
			state |= BMAP_LEFT_DELAY;
	}

	/*
	 * Check and set flags if this segment has a current value.
	 * Not true if we're inserting into the "hole" at eof.
	 */
	if (*idx < ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t)) {
		state |= BMAP_RIGHT_VALID;
		xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *idx), &right);
		if (isnullstartblock(right.br_startblock))
			state |= BMAP_RIGHT_DELAY;
	}

	/*
	 * We're inserting a real allocation between "left" and "right".
	 * Set the contiguity flags.  Don't let extents get too large.
	 */
	if ((state & BMAP_LEFT_VALID) && !(state & BMAP_LEFT_DELAY) &&
	    left.br_startoff + left.br_blockcount == new->br_startoff &&
	    left.br_startblock + left.br_blockcount == new->br_startblock &&
	    left.br_state == new->br_state &&
	    left.br_blockcount + new->br_blockcount <= MAXEXTLEN)
		state |= BMAP_LEFT_CONTIG;

	if ((state & BMAP_RIGHT_VALID) && !(state & BMAP_RIGHT_DELAY) &&
	    new->br_startoff + new->br_blockcount == right.br_startoff &&
	    new->br_startblock + new->br_blockcount == right.br_startblock &&
	    new->br_state == right.br_state &&
	    new->br_blockcount + right.br_blockcount <= MAXEXTLEN &&
	    (!(state & BMAP_LEFT_CONTIG) ||
	     left.br_blockcount + new->br_blockcount +
	     right.br_blockcount <= MAXEXTLEN))
		state |= BMAP_RIGHT_CONTIG;

	error = 0;
	/*
	 * Select which case we're in here, and implement it.
	 */
	switch (state & (BMAP_LEFT_CONTIG | BMAP_RIGHT_CONTIG)) {
	case BMAP_LEFT_CONTIG | BMAP_RIGHT_CONTIG:
		/*
		 * New allocation is contiguous with real allocations on the
		 * left and on the right.
		 * Merge all three into a single extent record.
		 */
		--*idx;
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, *idx),
			left.br_blockcount + new->br_blockcount +
			right.br_blockcount);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		xfs_iext_remove(ip, *idx + 1, 1, state);

		XFS_IFORK_NEXT_SET(ip, whichfork,
			XFS_IFORK_NEXTENTS(ip, whichfork) - 1);
		if (cur == NULL) {
			rval = XFS_ILOG_CORE | xfs_ilog_fext(whichfork);
		} else {
			rval = XFS_ILOG_CORE;
			if ((error = xfs_bmbt_lookup_eq(cur,
					right.br_startoff,
					right.br_startblock,
					right.br_blockcount, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_btree_delete(cur, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_btree_decrement(cur, 0, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur, left.br_startoff,
					left.br_startblock,
					left.br_blockcount +
						new->br_blockcount +
						right.br_blockcount,
					left.br_state)))
				goto done;
		}
		break;

	case BMAP_LEFT_CONTIG:
		/*
		 * New allocation is contiguous with a real allocation
		 * on the left.
		 * Merge the new allocation with the left neighbor.
		 */
		--*idx;
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(xfs_iext_get_ext(ifp, *idx),
			left.br_blockcount + new->br_blockcount);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		if (cur == NULL) {
			rval = xfs_ilog_fext(whichfork);
		} else {
			rval = 0;
			if ((error = xfs_bmbt_lookup_eq(cur,
					left.br_startoff,
					left.br_startblock,
					left.br_blockcount, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur, left.br_startoff,
					left.br_startblock,
					left.br_blockcount +
						new->br_blockcount,
					left.br_state)))
				goto done;
		}
		break;

	case BMAP_RIGHT_CONTIG:
		/*
		 * New allocation is contiguous with a real allocation
		 * on the right.
		 * Merge the new allocation with the right neighbor.
		 */
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_allf(xfs_iext_get_ext(ifp, *idx),
			new->br_startoff, new->br_startblock,
			new->br_blockcount + right.br_blockcount,
			right.br_state);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);

		if (cur == NULL) {
			rval = xfs_ilog_fext(whichfork);
		} else {
			rval = 0;
			if ((error = xfs_bmbt_lookup_eq(cur,
					right.br_startoff,
					right.br_startblock,
					right.br_blockcount, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			if ((error = xfs_bmbt_update(cur, new->br_startoff,
					new->br_startblock,
					new->br_blockcount +
						right.br_blockcount,
					right.br_state)))
				goto done;
		}
		break;

	case 0:
		/*
		 * New allocation is not contiguous with another
		 * real allocation.
		 * Insert a new entry.
		 */
		xfs_iext_insert(ip, *idx, 1, new, state);
		XFS_IFORK_NEXT_SET(ip, whichfork,
			XFS_IFORK_NEXTENTS(ip, whichfork) + 1);
		if (cur == NULL) {
			rval = XFS_ILOG_CORE | xfs_ilog_fext(whichfork);
		} else {
			rval = XFS_ILOG_CORE;
			if ((error = xfs_bmbt_lookup_eq(cur,
					new->br_startoff,
					new->br_startblock,
					new->br_blockcount, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 0, done);
			cur->bc_rec.b.br_state = new->br_state;
			if ((error = xfs_btree_insert(cur, &i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
		}
		break;
	}
done:
	*logflagsp = rval;
	return error;
}

/*
 * Adjust the size of the new extent based on di_extsize and rt extsize.
 */
STATIC int
xfs_bmap_extsize_align(
	xfs_mount_t	*mp,
	xfs_bmbt_irec_t	*gotp,		/* next extent pointer */
	xfs_bmbt_irec_t	*prevp,		/* previous extent pointer */
	xfs_extlen_t	extsz,		/* align to this extent size */
	int		rt,		/* is this a realtime inode? */
	int		eof,		/* is extent at end-of-file? */
	int		delay,		/* creating delalloc extent? */
	int		convert,	/* overwriting unwritten extent? */
	xfs_fileoff_t	*offp,		/* in/out: aligned offset */
	xfs_extlen_t	*lenp)		/* in/out: aligned length */
{
	xfs_fileoff_t	orig_off;	/* original offset */
	xfs_extlen_t	orig_alen;	/* original length */
	xfs_fileoff_t	orig_end;	/* original off+len */
	xfs_fileoff_t	nexto;		/* next file offset */
	xfs_fileoff_t	prevo;		/* previous file offset */
	xfs_fileoff_t	align_off;	/* temp for offset */
	xfs_extlen_t	align_alen;	/* temp for length */
	xfs_extlen_t	temp;		/* temp for calculations */

	if (convert)
		return 0;

	orig_off = align_off = *offp;
	orig_alen = align_alen = *lenp;
	orig_end = orig_off + orig_alen;

	/*
	 * If this request overlaps an existing extent, then don't
	 * attempt to perform any additional alignment.
	 */
	if (!delay && !eof &&
	    (orig_off >= gotp->br_startoff) &&
	    (orig_end <= gotp->br_startoff + gotp->br_blockcount)) {
		return 0;
	}

	/*
	 * If the file offset is unaligned vs. the extent size
	 * we need to align it.  This will be possible unless
	 * the file was previously written with a kernel that didn't
	 * perform this alignment, or if a truncate shot us in the
	 * foot.
	 */
	temp = do_mod(orig_off, extsz);
	if (temp) {
		align_alen += temp;
		align_off -= temp;
	}
	/*
	 * Same adjustment for the end of the requested area.
	 */
	if ((temp = (align_alen % extsz))) {
		align_alen += extsz - temp;
	}
	/*
	 * If the previous block overlaps with this proposed allocation
	 * then move the start forward without adjusting the length.
	 */
	if (prevp->br_startoff != NULLFILEOFF) {
		if (prevp->br_startblock == HOLESTARTBLOCK)
			prevo = prevp->br_startoff;
		else
			prevo = prevp->br_startoff + prevp->br_blockcount;
	} else
		prevo = 0;
	if (align_off != orig_off && align_off < prevo)
		align_off = prevo;
	/*
	 * If the next block overlaps with this proposed allocation
	 * then move the start back without adjusting the length,
	 * but not before offset 0.
	 * This may of course make the start overlap previous block,
	 * and if we hit the offset 0 limit then the next block
	 * can still overlap too.
	 */
	if (!eof && gotp->br_startoff != NULLFILEOFF) {
		if ((delay && gotp->br_startblock == HOLESTARTBLOCK) ||
		    (!delay && gotp->br_startblock == DELAYSTARTBLOCK))
			nexto = gotp->br_startoff + gotp->br_blockcount;
		else
			nexto = gotp->br_startoff;
	} else
		nexto = NULLFILEOFF;
	if (!eof &&
	    align_off + align_alen != orig_end &&
	    align_off + align_alen > nexto)
		align_off = nexto > align_alen ? nexto - align_alen : 0;
	/*
	 * If we're now overlapping the next or previous extent that
	 * means we can't fit an extsz piece in this hole.  Just move
	 * the start forward to the first valid spot and set
	 * the length so we hit the end.
	 */
	if (align_off != orig_off && align_off < prevo)
		align_off = prevo;
	if (align_off + align_alen != orig_end &&
	    align_off + align_alen > nexto &&
	    nexto != NULLFILEOFF) {
		ASSERT(nexto > prevo);
		align_alen = nexto - align_off;
	}

	/*
	 * If realtime, and the result isn't a multiple of the realtime
	 * extent size we need to remove blocks until it is.
	 */
	if (rt && (temp = (align_alen % mp->m_sb.sb_rextsize))) {
		/*
		 * We're not covering the original request, or
		 * we won't be able to once we fix the length.
		 */
		if (orig_off < align_off ||
		    orig_end > align_off + align_alen ||
		    align_alen - temp < orig_alen)
			return XFS_ERROR(EINVAL);
		/*
		 * Try to fix it by moving the start up.
		 */
		if (align_off + temp <= orig_off) {
			align_alen -= temp;
			align_off += temp;
		}
		/*
		 * Try to fix it by moving the end in.
		 */
		else if (align_off + align_alen - temp >= orig_end)
			align_alen -= temp;
		/*
		 * Set the start to the minimum then trim the length.
		 */
		else {
			align_alen -= orig_off - align_off;
			align_off = orig_off;
			align_alen -= align_alen % mp->m_sb.sb_rextsize;
		}
		/*
		 * Result doesn't cover the request, fail it.
		 */
		if (orig_off < align_off || orig_end > align_off + align_alen)
			return XFS_ERROR(EINVAL);
	} else {
		ASSERT(orig_off >= align_off);
		ASSERT(orig_end <= align_off + align_alen);
	}

#ifdef DEBUG
	if (!eof && gotp->br_startoff != NULLFILEOFF)
		ASSERT(align_off + align_alen <= gotp->br_startoff);
	if (prevp->br_startoff != NULLFILEOFF)
		ASSERT(align_off >= prevp->br_startoff + prevp->br_blockcount);
#endif

	*lenp = align_alen;
	*offp = align_off;
	return 0;
}

#define XFS_ALLOC_GAP_UNITS	4

STATIC void
xfs_bmap_adjacent(
	xfs_bmalloca_t	*ap)		/* bmap alloc argument struct */
{
	xfs_fsblock_t	adjust;		/* adjustment to block numbers */
	xfs_agnumber_t	fb_agno;	/* ag number of ap->firstblock */
	xfs_mount_t	*mp;		/* mount point structure */
	int		nullfb;		/* true if ap->firstblock isn't set */
	int		rt;		/* true if inode is realtime */

#define	ISVALID(x,y)	\
	(rt ? \
		(x) < mp->m_sb.sb_rblocks : \
		XFS_FSB_TO_AGNO(mp, x) == XFS_FSB_TO_AGNO(mp, y) && \
		XFS_FSB_TO_AGNO(mp, x) < mp->m_sb.sb_agcount && \
		XFS_FSB_TO_AGBNO(mp, x) < mp->m_sb.sb_agblocks)

	mp = ap->ip->i_mount;
	nullfb = ap->firstblock == NULLFSBLOCK;
	rt = XFS_IS_REALTIME_INODE(ap->ip) && ap->userdata;
	fb_agno = nullfb ? NULLAGNUMBER : XFS_FSB_TO_AGNO(mp, ap->firstblock);
	/*
	 * If allocating at eof, and there's a previous real block,
	 * try to use its last block as our starting point.
	 */
	if (ap->eof && ap->prevp->br_startoff != NULLFILEOFF &&
	    !isnullstartblock(ap->prevp->br_startblock) &&
	    ISVALID(ap->prevp->br_startblock + ap->prevp->br_blockcount,
		    ap->prevp->br_startblock)) {
		ap->rval = ap->prevp->br_startblock + ap->prevp->br_blockcount;
		/*
		 * Adjust for the gap between prevp and us.
		 */
		adjust = ap->off -
			(ap->prevp->br_startoff + ap->prevp->br_blockcount);
		if (adjust &&
		    ISVALID(ap->rval + adjust, ap->prevp->br_startblock))
			ap->rval += adjust;
	}
	/*
	 * If not at eof, then compare the two neighbor blocks.
	 * Figure out whether either one gives us a good starting point,
	 * and pick the better one.
	 */
	else if (!ap->eof) {
		xfs_fsblock_t	gotbno;		/* right side block number */
		xfs_fsblock_t	gotdiff=0;	/* right side difference */
		xfs_fsblock_t	prevbno;	/* left side block number */
		xfs_fsblock_t	prevdiff=0;	/* left side difference */

		/*
		 * If there's a previous (left) block, select a requested
		 * start block based on it.
		 */
		if (ap->prevp->br_startoff != NULLFILEOFF &&
		    !isnullstartblock(ap->prevp->br_startblock) &&
		    (prevbno = ap->prevp->br_startblock +
			       ap->prevp->br_blockcount) &&
		    ISVALID(prevbno, ap->prevp->br_startblock)) {
			/*
			 * Calculate gap to end of previous block.
			 */
			adjust = prevdiff = ap->off -
				(ap->prevp->br_startoff +
				 ap->prevp->br_blockcount);
			/*
			 * Figure the startblock based on the previous block's
			 * end and the gap size.
			 * Heuristic!
			 * If the gap is large relative to the piece we're
			 * allocating, or using it gives us an invalid block
			 * number, then just use the end of the previous block.
			 */
			if (prevdiff <= XFS_ALLOC_GAP_UNITS * ap->alen &&
			    ISVALID(prevbno + prevdiff,
				    ap->prevp->br_startblock))
				prevbno += adjust;
			else
				prevdiff += adjust;
			/*
			 * If the firstblock forbids it, can't use it,
			 * must use default.
			 */
			if (!rt && !nullfb &&
			    XFS_FSB_TO_AGNO(mp, prevbno) != fb_agno)
				prevbno = NULLFSBLOCK;
		}
		/*
		 * No previous block or can't follow it, just default.
		 */
		else
			prevbno = NULLFSBLOCK;
		/*
		 * If there's a following (right) block, select a requested
		 * start block based on it.
		 */
		if (!isnullstartblock(ap->gotp->br_startblock)) {
			/*
			 * Calculate gap to start of next block.
			 */
			adjust = gotdiff = ap->gotp->br_startoff - ap->off;
			/*
			 * Figure the startblock based on the next block's
			 * start and the gap size.
			 */
			gotbno = ap->gotp->br_startblock;
			/*
			 * Heuristic!
			 * If the gap is large relative to the piece we're
			 * allocating, or using it gives us an invalid block
			 * number, then just use the start of the next block
			 * offset by our length.
			 */
			if (gotdiff <= XFS_ALLOC_GAP_UNITS * ap->alen &&
			    ISVALID(gotbno - gotdiff, gotbno))
				gotbno -= adjust;
			else if (ISVALID(gotbno - ap->alen, gotbno)) {
				gotbno -= ap->alen;
				gotdiff += adjust - ap->alen;
			} else
				gotdiff += adjust;
			/*
			 * If the firstblock forbids it, can't use it,
			 * must use default.
			 */
			if (!rt && !nullfb &&
			    XFS_FSB_TO_AGNO(mp, gotbno) != fb_agno)
				gotbno = NULLFSBLOCK;
		}
		/*
		 * No next block, just default.
		 */
		else
			gotbno = NULLFSBLOCK;
		/*
		 * If both valid, pick the better one, else the only good
		 * one, else ap->rval is already set (to 0 or the inode block).
		 */
		if (prevbno != NULLFSBLOCK && gotbno != NULLFSBLOCK)
			ap->rval = prevdiff <= gotdiff ? prevbno : gotbno;
		else if (prevbno != NULLFSBLOCK)
			ap->rval = prevbno;
		else if (gotbno != NULLFSBLOCK)
			ap->rval = gotbno;
	}
#undef ISVALID
}

STATIC int
xfs_bmap_rtalloc(
	xfs_bmalloca_t	*ap)		/* bmap alloc argument struct */
{
	xfs_alloctype_t	atype = 0;	/* type for allocation routines */
	int		error;		/* error return value */
	xfs_mount_t	*mp;		/* mount point structure */
	xfs_extlen_t	prod = 0;	/* product factor for allocators */
	xfs_extlen_t	ralen = 0;	/* realtime allocation length */
	xfs_extlen_t	align;		/* minimum allocation alignment */
	xfs_rtblock_t	rtb;

	mp = ap->ip->i_mount;
	align = xfs_get_extsz_hint(ap->ip);
	prod = align / mp->m_sb.sb_rextsize;
	error = xfs_bmap_extsize_align(mp, ap->gotp, ap->prevp,
					align, 1, ap->eof, 0,
					ap->conv, &ap->off, &ap->alen);
	if (error)
		return error;
	ASSERT(ap->alen);
	ASSERT(ap->alen % mp->m_sb.sb_rextsize == 0);

	/*
	 * If the offset & length are not perfectly aligned
	 * then kill prod, it will just get us in trouble.
	 */
	if (do_mod(ap->off, align) || ap->alen % align)
		prod = 1;
	/*
	 * Set ralen to be the actual requested length in rtextents.
	 */
	ralen = ap->alen / mp->m_sb.sb_rextsize;
	/*
	 * If the old value was close enough to MAXEXTLEN that
	 * we rounded up to it, cut it back so it's valid again.
	 * Note that if it's a really large request (bigger than
	 * MAXEXTLEN), we don't hear about that number, and can't
	 * adjust the starting point to match it.
	 */
	if (ralen * mp->m_sb.sb_rextsize >= MAXEXTLEN)
		ralen = MAXEXTLEN / mp->m_sb.sb_rextsize;

	/*
	 * Lock out other modifications to the RT bitmap inode.
	 */
	xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL);
	xfs_trans_ijoin_ref(ap->tp, mp->m_rbmip, XFS_ILOCK_EXCL);

	/*
	 * If it's an allocation to an empty file at offset 0,
	 * pick an extent that will space things out in the rt area.
	 */
	if (ap->eof && ap->off == 0) {
		xfs_rtblock_t uninitialized_var(rtx); /* realtime extent no */

		error = xfs_rtpick_extent(mp, ap->tp, ralen, &rtx);
		if (error)
			return error;
		ap->rval = rtx * mp->m_sb.sb_rextsize;
	} else {
		ap->rval = 0;
	}

	xfs_bmap_adjacent(ap);

	/*
	 * Realtime allocation, done through xfs_rtallocate_extent.
	 */
	atype = ap->rval == 0 ?  XFS_ALLOCTYPE_ANY_AG : XFS_ALLOCTYPE_NEAR_BNO;
	do_div(ap->rval, mp->m_sb.sb_rextsize);
	rtb = ap->rval;
	ap->alen = ralen;
	if ((error = xfs_rtallocate_extent(ap->tp, ap->rval, 1, ap->alen,
				&ralen, atype, ap->wasdel, prod, &rtb)))
		return error;
	if (rtb == NULLFSBLOCK && prod > 1 &&
	    (error = xfs_rtallocate_extent(ap->tp, ap->rval, 1,
					   ap->alen, &ralen, atype,
					   ap->wasdel, 1, &rtb)))
		return error;
	ap->rval = rtb;
	if (ap->rval != NULLFSBLOCK) {
		ap->rval *= mp->m_sb.sb_rextsize;
		ralen *= mp->m_sb.sb_rextsize;
		ap->alen = ralen;
		ap->ip->i_d.di_nblocks += ralen;
		xfs_trans_log_inode(ap->tp, ap->ip, XFS_ILOG_CORE);
		if (ap->wasdel)
			ap->ip->i_delayed_blks -= ralen;
		/*
		 * Adjust the disk quota also. This was reserved
		 * earlier.
		 */
		xfs_trans_mod_dquot_byino(ap->tp, ap->ip,
			ap->wasdel ? XFS_TRANS_DQ_DELRTBCOUNT :
					XFS_TRANS_DQ_RTBCOUNT, (long) ralen);
	} else {
		ap->alen = 0;
	}
	return 0;
}

STATIC int
xfs_bmap_btalloc_nullfb(
	struct xfs_bmalloca	*ap,
	struct xfs_alloc_arg	*args,
	xfs_extlen_t		*blen)
{
	struct xfs_mount	*mp = ap->ip->i_mount;
	struct xfs_perag	*pag;
	xfs_agnumber_t		ag, startag;
	int			notinit = 0;
	int			error;

	if (ap->userdata && xfs_inode_is_filestream(ap->ip))
		args->type = XFS_ALLOCTYPE_NEAR_BNO;
	else
		args->type = XFS_ALLOCTYPE_START_BNO;
	args->total = ap->total;

	/*
	 * Search for an allocation group with a single extent large enough
	 * for the request.  If one isn't found, then adjust the minimum
	 * allocation size to the largest space found.
	 */
	startag = ag = XFS_FSB_TO_AGNO(mp, args->fsbno);
	if (startag == NULLAGNUMBER)
		startag = ag = 0;

	pag = xfs_perag_get(mp, ag);
	while (*blen < args->maxlen) {
		if (!pag->pagf_init) {
			error = xfs_alloc_pagf_init(mp, args->tp, ag,
						    XFS_ALLOC_FLAG_TRYLOCK);
			if (error) {
				xfs_perag_put(pag);
				return error;
			}
		}

		/*
		 * See xfs_alloc_fix_freelist...
		 */
		if (pag->pagf_init) {
			xfs_extlen_t	longest;
			longest = xfs_alloc_longest_free_extent(mp, pag);
			if (*blen < longest)
				*blen = longest;
		} else
			notinit = 1;

		if (xfs_inode_is_filestream(ap->ip)) {
			if (*blen >= args->maxlen)
				break;

			if (ap->userdata) {
				/*
				 * If startag is an invalid AG, we've
				 * come here once before and
				 * xfs_filestream_new_ag picked the
				 * best currently available.
				 *
				 * Don't continue looping, since we
				 * could loop forever.
				 */
				if (startag == NULLAGNUMBER)
					break;

				error = xfs_filestream_new_ag(ap, &ag);
				xfs_perag_put(pag);
				if (error)
					return error;

				/* loop again to set 'blen'*/
				startag = NULLAGNUMBER;
				pag = xfs_perag_get(mp, ag);
				continue;
			}
		}
		if (++ag == mp->m_sb.sb_agcount)
			ag = 0;
		if (ag == startag)
			break;
		xfs_perag_put(pag);
		pag = xfs_perag_get(mp, ag);
	}
	xfs_perag_put(pag);

	/*
	 * Since the above loop did a BUF_TRYLOCK, it is
	 * possible that there is space for this request.
	 */
	if (notinit || *blen < ap->minlen)
		args->minlen = ap->minlen;
	/*
	 * If the best seen length is less than the request
	 * length, use the best as the minimum.
	 */
	else if (*blen < args->maxlen)
		args->minlen = *blen;
	/*
	 * Otherwise we've seen an extent as big as maxlen,
	 * use that as the minimum.
	 */
	else
		args->minlen = args->maxlen;

	/*
	 * set the failure fallback case to look in the selected
	 * AG as the stream may have moved.
	 */
	if (xfs_inode_is_filestream(ap->ip))
		ap->rval = args->fsbno = XFS_AGB_TO_FSB(mp, ag, 0);

	return 0;
}

STATIC int
xfs_bmap_btalloc(
	xfs_bmalloca_t	*ap)		/* bmap alloc argument struct */
{
	xfs_mount_t	*mp;		/* mount point structure */
	xfs_alloctype_t	atype = 0;	/* type for allocation routines */
	xfs_extlen_t	align;		/* minimum allocation alignment */
	xfs_agnumber_t	fb_agno;	/* ag number of ap->firstblock */
	xfs_agnumber_t	ag;
	xfs_alloc_arg_t	args;
	xfs_extlen_t	blen;
	xfs_extlen_t	nextminlen = 0;
	int		nullfb;		/* true if ap->firstblock isn't set */
	int		isaligned;
	int		tryagain;
	int		error;

	mp = ap->ip->i_mount;
	align = ap->userdata ? xfs_get_extsz_hint(ap->ip) : 0;
	if (unlikely(align)) {
		error = xfs_bmap_extsize_align(mp, ap->gotp, ap->prevp,
						align, 0, ap->eof, 0, ap->conv,
						&ap->off, &ap->alen);
		ASSERT(!error);
		ASSERT(ap->alen);
	}
	nullfb = ap->firstblock == NULLFSBLOCK;
	fb_agno = nullfb ? NULLAGNUMBER : XFS_FSB_TO_AGNO(mp, ap->firstblock);
	if (nullfb) {
		if (ap->userdata && xfs_inode_is_filestream(ap->ip)) {
			ag = xfs_filestream_lookup_ag(ap->ip);
			ag = (ag != NULLAGNUMBER) ? ag : 0;
			ap->rval = XFS_AGB_TO_FSB(mp, ag, 0);
		} else {
			ap->rval = XFS_INO_TO_FSB(mp, ap->ip->i_ino);
		}
	} else
		ap->rval = ap->firstblock;

	xfs_bmap_adjacent(ap);

	/*
	 * If allowed, use ap->rval; otherwise must use firstblock since
	 * it's in the right allocation group.
	 */
	if (nullfb || XFS_FSB_TO_AGNO(mp, ap->rval) == fb_agno)
		;
	else
		ap->rval = ap->firstblock;
	/*
	 * Normal allocation, done through xfs_alloc_vextent.
	 */
	tryagain = isaligned = 0;
	args.tp = ap->tp;
	args.mp = mp;
	args.fsbno = ap->rval;

	/* Trim the allocation back to the maximum an AG can fit. */
	args.maxlen = MIN(ap->alen, XFS_ALLOC_AG_MAX_USABLE(mp));
	args.firstblock = ap->firstblock;
	blen = 0;
	if (nullfb) {
		error = xfs_bmap_btalloc_nullfb(ap, &args, &blen);
		if (error)
			return error;
	} else if (ap->low) {
		if (xfs_inode_is_filestream(ap->ip))
			args.type = XFS_ALLOCTYPE_FIRST_AG;
		else
			args.type = XFS_ALLOCTYPE_START_BNO;
		args.total = args.minlen = ap->minlen;
	} else {
		args.type = XFS_ALLOCTYPE_NEAR_BNO;
		args.total = ap->total;
		args.minlen = ap->minlen;
	}
	/* apply extent size hints if obtained earlier */
	if (unlikely(align)) {
		args.prod = align;
		if ((args.mod = (xfs_extlen_t)do_mod(ap->off, args.prod)))
			args.mod = (xfs_extlen_t)(args.prod - args.mod);
	} else if (mp->m_sb.sb_blocksize >= PAGE_CACHE_SIZE) {
		args.prod = 1;
		args.mod = 0;
	} else {
		args.prod = PAGE_CACHE_SIZE >> mp->m_sb.sb_blocklog;
		if ((args.mod = (xfs_extlen_t)(do_mod(ap->off, args.prod))))
			args.mod = (xfs_extlen_t)(args.prod - args.mod);
	}
	/*
	 * If we are not low on available data blocks, and the
	 * underlying logical volume manager is a stripe, and
	 * the file offset is zero then try to allocate data
	 * blocks on stripe unit boundary.
	 * NOTE: ap->aeof is only set if the allocation length
	 * is >= the stripe unit and the allocation offset is
	 * at the end of file.
	 */
	if (!ap->low && ap->aeof) {
		if (!ap->off) {
			args.alignment = mp->m_dalign;
			atype = args.type;
			isaligned = 1;
			/*
			 * Adjust for alignment
			 */
			if (blen > args.alignment && blen <= args.maxlen)
				args.minlen = blen - args.alignment;
			args.minalignslop = 0;
		} else {
			/*
			 * First try an exact bno allocation.
			 * If it fails then do a near or start bno
			 * allocation with alignment turned on.
			 */
			atype = args.type;
			tryagain = 1;
			args.type = XFS_ALLOCTYPE_THIS_BNO;
			args.alignment = 1;
			/*
			 * Compute the minlen+alignment for the
			 * next case.  Set slop so that the value
			 * of minlen+alignment+slop doesn't go up
			 * between the calls.
			 */
			if (blen > mp->m_dalign && blen <= args.maxlen)
				nextminlen = blen - mp->m_dalign;
			else
				nextminlen = args.minlen;
			if (nextminlen + mp->m_dalign > args.minlen + 1)
				args.minalignslop =
					nextminlen + mp->m_dalign -
					args.minlen - 1;
			else
				args.minalignslop = 0;
		}
	} else {
		args.alignment = 1;
		args.minalignslop = 0;
	}
	args.minleft = ap->minleft;
	args.wasdel = ap->wasdel;
	args.isfl = 0;
	args.userdata = ap->userdata;
	if ((error = xfs_alloc_vextent(&args)))
		return error;
	if (tryagain && args.fsbno == NULLFSBLOCK) {
		/*
		 * Exact allocation failed. Now try with alignment
		 * turned on.
		 */
		args.type = atype;
		args.fsbno = ap->rval;
		args.alignment = mp->m_dalign;
		args.minlen = nextminlen;
		args.minalignslop = 0;
		isaligned = 1;
		if ((error = xfs_alloc_vextent(&args)))
			return error;
	}
	if (isaligned && args.fsbno == NULLFSBLOCK) {
		/*
		 * allocation failed, so turn off alignment and
		 * try again.
		 */
		args.type = atype;
		args.fsbno = ap->rval;
		args.alignment = 0;
		if ((error = xfs_alloc_vextent(&args)))
			return error;
	}
	if (args.fsbno == NULLFSBLOCK && nullfb &&
	    args.minlen > ap->minlen) {
		args.minlen = ap->minlen;
		args.type = XFS_ALLOCTYPE_START_BNO;
		args.fsbno = ap->rval;
		if ((error = xfs_alloc_vextent(&args)))
			return error;
	}
	if (args.fsbno == NULLFSBLOCK && nullfb) {
		args.fsbno = 0;
		args.type = XFS_ALLOCTYPE_FIRST_AG;
		args.total = ap->minlen;
		args.minleft = 0;
		if ((error = xfs_alloc_vextent(&args)))
			return error;
		ap->low = 1;
	}
	if (args.fsbno != NULLFSBLOCK) {
		ap->firstblock = ap->rval = args.fsbno;
		ASSERT(nullfb || fb_agno == args.agno ||
		       (ap->low && fb_agno < args.agno));
		ap->alen = args.len;
		ap->ip->i_d.di_nblocks += args.len;
		xfs_trans_log_inode(ap->tp, ap->ip, XFS_ILOG_CORE);
		if (ap->wasdel)
			ap->ip->i_delayed_blks -= args.len;
		/*
		 * Adjust the disk quota also. This was reserved
		 * earlier.
		 */
		xfs_trans_mod_dquot_byino(ap->tp, ap->ip,
			ap->wasdel ? XFS_TRANS_DQ_DELBCOUNT :
					XFS_TRANS_DQ_BCOUNT,
			(long) args.len);
	} else {
		ap->rval = NULLFSBLOCK;
		ap->alen = 0;
	}
	return 0;
}

/*
 * xfs_bmap_alloc is called by xfs_bmapi to allocate an extent for a file.
 * It figures out where to ask the underlying allocator to put the new extent.
 */
STATIC int
xfs_bmap_alloc(
	xfs_bmalloca_t	*ap)		/* bmap alloc argument struct */
{
	if (XFS_IS_REALTIME_INODE(ap->ip) && ap->userdata)
		return xfs_bmap_rtalloc(ap);
	return xfs_bmap_btalloc(ap);
}

/*
 * Transform a btree format file with only one leaf node, where the
 * extents list will fit in the inode, into an extents format file.
 * Since the file extents are already in-core, all we have to do is
 * give up the space for the btree root and pitch the leaf block.
 */
STATIC int				/* error */
xfs_bmap_btree_to_extents(
	xfs_trans_t		*tp,	/* transaction pointer */
	xfs_inode_t		*ip,	/* incore inode pointer */
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			*logflagsp, /* inode logging flags */
	int			whichfork)  /* data or attr fork */
{
	/* REFERENCED */
	struct xfs_btree_block	*cblock;/* child btree block */
	xfs_fsblock_t		cbno;	/* child block number */
	xfs_buf_t		*cbp;	/* child block's buffer */
	int			error;	/* error return value */
	xfs_ifork_t		*ifp;	/* inode fork data */
	xfs_mount_t		*mp;	/* mount point structure */
	__be64			*pp;	/* ptr to block address */
	struct xfs_btree_block	*rblock;/* root btree block */

	mp = ip->i_mount;
	ifp = XFS_IFORK_PTR(ip, whichfork);
	ASSERT(ifp->if_flags & XFS_IFEXTENTS);
	ASSERT(XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_BTREE);
	rblock = ifp->if_broot;
	ASSERT(be16_to_cpu(rblock->bb_level) == 1);
	ASSERT(be16_to_cpu(rblock->bb_numrecs) == 1);
	ASSERT(xfs_bmbt_maxrecs(mp, ifp->if_broot_bytes, 0) == 1);
	pp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, ifp->if_broot_bytes);
	cbno = be64_to_cpu(*pp);
	*logflagsp = 0;
#ifdef DEBUG
	if ((error = xfs_btree_check_lptr(cur, cbno, 1)))
		return error;
#endif
	if ((error = xfs_btree_read_bufl(mp, tp, cbno, 0, &cbp,
			XFS_BMAP_BTREE_REF)))
		return error;
	cblock = XFS_BUF_TO_BLOCK(cbp);
	if ((error = xfs_btree_check_block(cur, cblock, 0, cbp)))
		return error;
	xfs_bmap_add_free(cbno, 1, cur->bc_private.b.flist, mp);
	ip->i_d.di_nblocks--;
	xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
	xfs_trans_binval(tp, cbp);
	if (cur->bc_bufs[0] == cbp)
		cur->bc_bufs[0] = NULL;
	xfs_iroot_realloc(ip, -1, whichfork);
	ASSERT(ifp->if_broot == NULL);
	ASSERT((ifp->if_flags & XFS_IFBROOT) == 0);
	XFS_IFORK_FMT_SET(ip, whichfork, XFS_DINODE_FMT_EXTENTS);
	*logflagsp = XFS_ILOG_CORE | xfs_ilog_fext(whichfork);
	return 0;
}

/*
 * Called by xfs_bmapi to update file extent records and the btree
 * after removing space (or undoing a delayed allocation).
 */
STATIC int				/* error */
xfs_bmap_del_extent(
	xfs_inode_t		*ip,	/* incore inode pointer */
	xfs_trans_t		*tp,	/* current transaction pointer */
	xfs_extnum_t		*idx,	/* extent number to update/delete */
	xfs_bmap_free_t		*flist,	/* list of extents to be freed */
	xfs_btree_cur_t		*cur,	/* if null, not a btree */
	xfs_bmbt_irec_t		*del,	/* data to remove from extents */
	int			*logflagsp, /* inode logging flags */
	int			whichfork) /* data or attr fork */
{
	xfs_filblks_t		da_new;	/* new delay-alloc indirect blocks */
	xfs_filblks_t		da_old;	/* old delay-alloc indirect blocks */
	xfs_fsblock_t		del_endblock=0;	/* first block past del */
	xfs_fileoff_t		del_endoff;	/* first offset past del */
	int			delay;	/* current block is delayed allocated */
	int			do_fx;	/* free extent at end of routine */
	xfs_bmbt_rec_host_t	*ep;	/* current extent entry pointer */
	int			error;	/* error return value */
	int			flags;	/* inode logging flags */
	xfs_bmbt_irec_t		got;	/* current extent entry */
	xfs_fileoff_t		got_endoff;	/* first offset past got */
	int			i;	/* temp state */
	xfs_ifork_t		*ifp;	/* inode fork pointer */
	xfs_mount_t		*mp;	/* mount structure */
	xfs_filblks_t		nblks;	/* quota/sb block count */
	xfs_bmbt_irec_t		new;	/* new record to be inserted */
	/* REFERENCED */
	uint			qfield;	/* quota field to update */
	xfs_filblks_t		temp;	/* for indirect length calculations */
	xfs_filblks_t		temp2;	/* for indirect length calculations */
	int			state = 0;

	XFS_STATS_INC(xs_del_exlist);

	if (whichfork == XFS_ATTR_FORK)
		state |= BMAP_ATTRFORK;

	mp = ip->i_mount;
	ifp = XFS_IFORK_PTR(ip, whichfork);
	ASSERT((*idx >= 0) && (*idx < ifp->if_bytes /
		(uint)sizeof(xfs_bmbt_rec_t)));
	ASSERT(del->br_blockcount > 0);
	ep = xfs_iext_get_ext(ifp, *idx);
	xfs_bmbt_get_all(ep, &got);
	ASSERT(got.br_startoff <= del->br_startoff);
	del_endoff = del->br_startoff + del->br_blockcount;
	got_endoff = got.br_startoff + got.br_blockcount;
	ASSERT(got_endoff >= del_endoff);
	delay = isnullstartblock(got.br_startblock);
	ASSERT(isnullstartblock(del->br_startblock) == delay);
	flags = 0;
	qfield = 0;
	error = 0;
	/*
	 * If deleting a real allocation, must free up the disk space.
	 */
	if (!delay) {
		flags = XFS_ILOG_CORE;
		/*
		 * Realtime allocation.  Free it and record di_nblocks update.
		 */
		if (whichfork == XFS_DATA_FORK && XFS_IS_REALTIME_INODE(ip)) {
			xfs_fsblock_t	bno;
			xfs_filblks_t	len;

			ASSERT(do_mod(del->br_blockcount,
				      mp->m_sb.sb_rextsize) == 0);
			ASSERT(do_mod(del->br_startblock,
				      mp->m_sb.sb_rextsize) == 0);
			bno = del->br_startblock;
			len = del->br_blockcount;
			do_div(bno, mp->m_sb.sb_rextsize);
			do_div(len, mp->m_sb.sb_rextsize);
			if ((error = xfs_rtfree_extent(ip->i_transp, bno,
					(xfs_extlen_t)len)))
				goto done;
			do_fx = 0;
			nblks = len * mp->m_sb.sb_rextsize;
			qfield = XFS_TRANS_DQ_RTBCOUNT;
		}
		/*
		 * Ordinary allocation.
		 */
		else {
			do_fx = 1;
			nblks = del->br_blockcount;
			qfield = XFS_TRANS_DQ_BCOUNT;
		}
		/*
		 * Set up del_endblock and cur for later.
		 */
		del_endblock = del->br_startblock + del->br_blockcount;
		if (cur) {
			if ((error = xfs_bmbt_lookup_eq(cur, got.br_startoff,
					got.br_startblock, got.br_blockcount,
					&i)))
				goto done;
			XFS_WANT_CORRUPTED_GOTO(i == 1, done);
		}
		da_old = da_new = 0;
	} else {
		da_old = startblockval(got.br_startblock);
		da_new = 0;
		nblks = 0;
		do_fx = 0;
	}
	/*
	 * Set flag value to use in switch statement.
	 * Left-contig is 2, right-contig is 1.
	 */
	switch (((got.br_startoff == del->br_startoff) << 1) |
		(got_endoff == del_endoff)) {
	case 3:
		/*
		 * Matches the whole extent.  Delete the entry.
		 */
		xfs_iext_remove(ip, *idx, 1,
				whichfork == XFS_ATTR_FORK ? BMAP_ATTRFORK : 0);
		--*idx;
		if (delay)
			break;

		XFS_IFORK_NEXT_SET(ip, whichfork,
			XFS_IFORK_NEXTENTS(ip, whichfork) - 1);
		flags |= XFS_ILOG_CORE;
		if (!cur) {
			flags |= xfs_ilog_fext(whichfork);
			break;
		}
		if ((error = xfs_btree_delete(cur, &i)))
			goto done;
		XFS_WANT_CORRUPTED_GOTO(i == 1, done);
		break;

	case 2:
		/*
		 * Deleting the first part of the extent.
		 */
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_startoff(ep, del_endoff);
		temp = got.br_blockcount - del->br_blockcount;
		xfs_bmbt_set_blockcount(ep, temp);
		if (delay) {
			temp = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp),
				da_old);
			xfs_bmbt_set_startblock(ep, nullstartblock((int)temp));
			trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
			da_new = temp;
			break;
		}
		xfs_bmbt_set_startblock(ep, del_endblock);
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
		if (!cur) {
			flags |= xfs_ilog_fext(whichfork);
			break;
		}
		if ((error = xfs_bmbt_update(cur, del_endoff, del_endblock,
				got.br_blockcount - del->br_blockcount,
				got.br_state)))
			goto done;
		break;

	case 1:
		/*
		 * Deleting the last part of the extent.
		 */
		temp = got.br_blockcount - del->br_blockcount;
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(ep, temp);
		if (delay) {
			temp = XFS_FILBLKS_MIN(xfs_bmap_worst_indlen(ip, temp),
				da_old);
			xfs_bmbt_set_startblock(ep, nullstartblock((int)temp));
			trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
			da_new = temp;
			break;
		}
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
		if (!cur) {
			flags |= xfs_ilog_fext(whichfork);
			break;
		}
		if ((error = xfs_bmbt_update(cur, got.br_startoff,
				got.br_startblock,
				got.br_blockcount - del->br_blockcount,
				got.br_state)))
			goto done;
		break;

	case 0:
		/*
		 * Deleting the middle of the extent.
		 */
		temp = del->br_startoff - got.br_startoff;
		trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
		xfs_bmbt_set_blockcount(ep, temp);
		new.br_startoff = del_endoff;
		temp2 = got_endoff - del_endoff;
		new.br_blockcount = temp2;
		new.br_state = got.br_state;
		if (!delay) {
			new.br_startblock = del_endblock;
			flags |= XFS_ILOG_CORE;
			if (cur) {
				if ((error = xfs_bmbt_update(cur,
						got.br_startoff,
						got.br_startblock, temp,
						got.br_state)))
					goto done;
				if ((error = xfs_btree_increment(cur, 0, &i)))
					goto done;
				cur->bc_rec.b = new;
				error = xfs_btree_insert(cur, &i);
				if (error && error != ENOSPC)
					goto done;
				/*
				 * If get no-space back from btree insert,
				 * it tried a split, and we have a zero
				 * block reservation.
				 * Fix up our state and return the error.
				 */
				if (error == ENOSPC) {
					/*
					 * Reset the cursor, don't trust
					 * it after any insert operation.
					 */
					if ((error = xfs_bmbt_lookup_eq(cur,
							got.br_startoff,
							got.br_startblock,
							temp, &i)))
						goto done;
					XFS_WANT_CORRUPTED_GOTO(i == 1, done);
					/*
					 * Update the btree record back
					 * to the original value.
					 */
					if ((error = xfs_bmbt_update(cur,
							got.br_startoff,
							got.br_startblock,
							got.br_blockcount,
							got.br_state)))
						goto done;
					/*
					 * Reset the extent record back
					 * to the original value.
					 */
					xfs_bmbt_set_blockcount(ep,
						got.br_blockcount);
					flags = 0;
					error = XFS_ERROR(ENOSPC);
					goto done;
				}
				XFS_WANT_CORRUPTED_GOTO(i == 1, done);
			} else
				flags |= xfs_ilog_fext(whichfork);
			XFS_IFORK_NEXT_SET(ip, whichfork,
				XFS_IFORK_NEXTENTS(ip, whichfork) + 1);
		} else {
			ASSERT(whichfork == XFS_DATA_FORK);
			temp = xfs_bmap_worst_indlen(ip, temp);
			xfs_bmbt_set_startblock(ep, nullstartblock((int)temp));
			temp2 = xfs_bmap_worst_indlen(ip, temp2);
			new.br_startblock = nullstartblock((int)temp2);
			da_new = temp + temp2;
			while (da_new > da_old) {
				if (temp) {
					temp--;
					da_new--;
					xfs_bmbt_set_startblock(ep,
						nullstartblock((int)temp));
				}
				if (da_new == da_old)
					break;
				if (temp2) {
					temp2--;
					da_new--;
					new.br_startblock =
						nullstartblock((int)temp2);
				}
			}
		}
		trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
		xfs_iext_insert(ip, *idx + 1, 1, &new, state);
		++*idx;
		break;
	}
	/*
	 * If we need to, add to list of extents to delete.
	 */
	if (do_fx)
		xfs_bmap_add_free(del->br_startblock, del->br_blockcount, flist,
			mp);
	/*
	 * Adjust inode # blocks in the file.
	 */
	if (nblks)
		ip->i_d.di_nblocks -= nblks;
	/*
	 * Adjust quota data.
	 */
	if (qfield)
		xfs_trans_mod_dquot_byino(tp, ip, qfield, (long)-nblks);

	/*
	 * Account for change in delayed indirect blocks.
	 * Nothing to do for disk quota accounting here.
	 */
	ASSERT(da_old >= da_new);
	if (da_old > da_new) {
		xfs_icsb_modify_counters(mp, XFS_SBS_FDBLOCKS,
			(int64_t)(da_old - da_new), 0);
	}
done:
	*logflagsp = flags;
	return error;
}

/*
 * Remove the entry "free" from the free item list.  Prev points to the
 * previous entry, unless "free" is the head of the list.
 */
STATIC void
xfs_bmap_del_free(
	xfs_bmap_free_t		*flist,	/* free item list header */
	xfs_bmap_free_item_t	*prev,	/* previous item on list, if any */
	xfs_bmap_free_item_t	*free)	/* list item to be freed */
{
	if (prev)
		prev->xbfi_next = free->xbfi_next;
	else
		flist->xbf_first = free->xbfi_next;
	flist->xbf_count--;
	kmem_zone_free(xfs_bmap_free_item_zone, free);
}

/*
 * Convert an extents-format file into a btree-format file.
 * The new file will have a root block (in the inode) and a single child block.
 */
STATIC int					/* error */
xfs_bmap_extents_to_btree(
	xfs_trans_t		*tp,		/* transaction pointer */
	xfs_inode_t		*ip,		/* incore inode pointer */
	xfs_fsblock_t		*firstblock,	/* first-block-allocated */
	xfs_bmap_free_t		*flist,		/* blocks freed in xaction */
	xfs_btree_cur_t		**curp,		/* cursor returned to caller */
	int			wasdel,		/* converting a delayed alloc */
	int			*logflagsp,	/* inode logging flags */
	int			whichfork)	/* data or attr fork */
{
	struct xfs_btree_block	*ablock;	/* allocated (child) bt block */
	xfs_buf_t		*abp;		/* buffer for ablock */
	xfs_alloc_arg_t		args;		/* allocation arguments */
	xfs_bmbt_rec_t		*arp;		/* child record pointer */
	struct xfs_btree_block	*block;		/* btree root block */
	xfs_btree_cur_t		*cur;		/* bmap btree cursor */
	xfs_bmbt_rec_host_t	*ep;		/* extent record pointer */
	int			error;		/* error return value */
	xfs_extnum_t		i, cnt;		/* extent record index */
	xfs_ifork_t		*ifp;		/* inode fork pointer */
	xfs_bmbt_key_t		*kp;		/* root block key pointer */
	xfs_mount_t		*mp;		/* mount structure */
	xfs_extnum_t		nextents;	/* number of file extents */
	xfs_bmbt_ptr_t		*pp;		/* root block address pointer */

	ifp = XFS_IFORK_PTR(ip, whichfork);
	ASSERT(XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS);
	ASSERT(ifp->if_ext_max ==
	       XFS_IFORK_SIZE(ip, whichfork) / (uint)sizeof(xfs_bmbt_rec_t));
	/*
	 * Make space in the inode incore.
	 */
	xfs_iroot_realloc(ip, 1, whichfork);
	ifp->if_flags |= XFS_IFBROOT;

	/*
	 * Fill in the root.
	 */
	block = ifp->if_broot;
	block->bb_magic = cpu_to_be32(XFS_BMAP_MAGIC);
	block->bb_level = cpu_to_be16(1);
	block->bb_numrecs = cpu_to_be16(1);
	block->bb_u.l.bb_leftsib = cpu_to_be64(NULLDFSBNO);
	block->bb_u.l.bb_rightsib = cpu_to_be64(NULLDFSBNO);

	/*
	 * Need a cursor.  Can't allocate until bb_level is filled in.
	 */
	mp = ip->i_mount;
	cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
	cur->bc_private.b.firstblock = *firstblock;
	cur->bc_private.b.flist = flist;
	cur->bc_private.b.flags = wasdel ? XFS_BTCUR_BPRV_WASDEL : 0;
	/*
	 * Convert to a btree with two levels, one record in root.
	 */
	XFS_IFORK_FMT_SET(ip, whichfork, XFS_DINODE_FMT_BTREE);
	args.tp = tp;
	args.mp = mp;
	args.firstblock = *firstblock;
	if (*firstblock == NULLFSBLOCK) {
		args.type = XFS_ALLOCTYPE_START_BNO;
		args.fsbno = XFS_INO_TO_FSB(mp, ip->i_ino);
	} else if (flist->xbf_low) {
		args.type = XFS_ALLOCTYPE_START_BNO;
		args.fsbno = *firstblock;
	} else {
		args.type = XFS_ALLOCTYPE_NEAR_BNO;
		args.fsbno = *firstblock;
	}
	args.minlen = args.maxlen = args.prod = 1;
	args.total = args.minleft = args.alignment = args.mod = args.isfl =
		args.minalignslop = 0;
	args.wasdel = wasdel;
	*logflagsp = 0;
	if ((error = xfs_alloc_vextent(&args))) {
		xfs_iroot_realloc(ip, -1, whichfork);
		xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
		return error;
	}
	/*
	 * Allocation can't fail, the space was reserved.
	 */
	ASSERT(args.fsbno != NULLFSBLOCK);
	ASSERT(*firstblock == NULLFSBLOCK ||
	       args.agno == XFS_FSB_TO_AGNO(mp, *firstblock) ||
	       (flist->xbf_low &&
		args.agno > XFS_FSB_TO_AGNO(mp, *firstblock)));
	*firstblock = cur->bc_private.b.firstblock = args.fsbno;
	cur->bc_private.b.allocated++;
	ip->i_d.di_nblocks++;
	xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, 1L);
	abp = xfs_btree_get_bufl(mp, tp, args.fsbno, 0);
	/*
	 * Fill in the child block.
	 */
	ablock = XFS_BUF_TO_BLOCK(abp);
	ablock->bb_magic = cpu_to_be32(XFS_BMAP_MAGIC);
	ablock->bb_level = 0;
	ablock->bb_u.l.bb_leftsib = cpu_to_be64(NULLDFSBNO);
	ablock->bb_u.l.bb_rightsib = cpu_to_be64(NULLDFSBNO);
	arp = XFS_BMBT_REC_ADDR(mp, ablock, 1);
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	for (cnt = i = 0; i < nextents; i++) {
		ep = xfs_iext_get_ext(ifp, i);
		if (!isnullstartblock(xfs_bmbt_get_startblock(ep))) {
			arp->l0 = cpu_to_be64(ep->l0);
			arp->l1 = cpu_to_be64(ep->l1);
			arp++; cnt++;
		}
	}
	ASSERT(cnt == XFS_IFORK_NEXTENTS(ip, whichfork));
	xfs_btree_set_numrecs(ablock, cnt);

	/*
	 * Fill in the root key and pointer.
	 */
	kp = XFS_BMBT_KEY_ADDR(mp, block, 1);
	arp = XFS_BMBT_REC_ADDR(mp, ablock, 1);
	kp->br_startoff = cpu_to_be64(xfs_bmbt_disk_get_startoff(arp));
	pp = XFS_BMBT_PTR_ADDR(mp, block, 1, xfs_bmbt_get_maxrecs(cur,
						be16_to_cpu(block->bb_level)));
	*pp = cpu_to_be64(args.fsbno);

	/*
	 * Do all this logging at the end so that
	 * the root is at the right level.
	 */
	xfs_btree_log_block(cur, abp, XFS_BB_ALL_BITS);
	xfs_btree_log_recs(cur, abp, 1, be16_to_cpu(ablock->bb_numrecs));
	ASSERT(*curp == NULL);
	*curp = cur;
	*logflagsp = XFS_ILOG_CORE | xfs_ilog_fbroot(whichfork);
	return 0;
}

/*
 * Calculate the default attribute fork offset for newly created inodes.
 */
uint
xfs_default_attroffset(
	struct xfs_inode	*ip)
{
	struct xfs_mount	*mp = ip->i_mount;
	uint			offset;

	if (mp->m_sb.sb_inodesize == 256) {
		offset = XFS_LITINO(mp) -
				XFS_BMDR_SPACE_CALC(MINABTPTRS);
	} else {
		offset = XFS_BMDR_SPACE_CALC(6 * MINABTPTRS);
	}

	ASSERT(offset < XFS_LITINO(mp));
	return offset;
}

/*
 * Helper routine to reset inode di_forkoff field when switching
 * attribute fork from local to extent format - we reset it where
 * possible to make space available for inline data fork extents.
 */
STATIC void
xfs_bmap_forkoff_reset(
	xfs_mount_t	*mp,
	xfs_inode_t	*ip,
	int		whichfork)
{
	if (whichfork == XFS_ATTR_FORK &&
	    ip->i_d.di_format != XFS_DINODE_FMT_DEV &&
	    ip->i_d.di_format != XFS_DINODE_FMT_UUID &&
	    ip->i_d.di_format != XFS_DINODE_FMT_BTREE) {
		uint	dfl_forkoff = xfs_default_attroffset(ip) >> 3;

		if (dfl_forkoff > ip->i_d.di_forkoff) {
			ip->i_d.di_forkoff = dfl_forkoff;
			ip->i_df.if_ext_max =
				XFS_IFORK_DSIZE(ip) / sizeof(xfs_bmbt_rec_t);
			ip->i_afp->if_ext_max =
				XFS_IFORK_ASIZE(ip) / sizeof(xfs_bmbt_rec_t);
		}
	}
}

/*
 * Convert a local file to an extents file.
 * This code is out of bounds for data forks of regular files,
 * since the file data needs to get logged so things will stay consistent.
 * (The bmap-level manipulations are ok, though).
 */
STATIC int				/* error */
xfs_bmap_local_to_extents(
	xfs_trans_t	*tp,		/* transaction pointer */
	xfs_inode_t	*ip,		/* incore inode pointer */
	xfs_fsblock_t	*firstblock,	/* first block allocated in xaction */
	xfs_extlen_t	total,		/* total blocks needed by transaction */
	int		*logflagsp,	/* inode logging flags */
	int		whichfork)	/* data or attr fork */
{
	int		error;		/* error return value */
	int		flags;		/* logging flags returned */
	xfs_ifork_t	*ifp;		/* inode fork pointer */

	/*
	 * We don't want to deal with the case of keeping inode data inline yet.
	 * So sending the data fork of a regular inode is invalid.
	 */
	ASSERT(!((ip->i_d.di_mode & S_IFMT) == S_IFREG &&
		 whichfork == XFS_DATA_FORK));
	ifp = XFS_IFORK_PTR(ip, whichfork);
	ASSERT(XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL);
	flags = 0;
	error = 0;
	if (ifp->if_bytes) {
		xfs_alloc_arg_t	args;	/* allocation arguments */
		xfs_buf_t	*bp;	/* buffer for extent block */
		xfs_bmbt_rec_host_t *ep;/* extent record pointer */

		args.tp = tp;
		args.mp = ip->i_mount;
		args.firstblock = *firstblock;
		ASSERT((ifp->if_flags &
			(XFS_IFINLINE|XFS_IFEXTENTS|XFS_IFEXTIREC)) == XFS_IFINLINE);
		/*
		 * Allocate a block.  We know we need only one, since the
		 * file currently fits in an inode.
		 */
		if (*firstblock == NULLFSBLOCK) {
			args.fsbno = XFS_INO_TO_FSB(args.mp, ip->i_ino);
			args.type = XFS_ALLOCTYPE_START_BNO;
		} else {
			args.fsbno = *firstblock;
			args.type = XFS_ALLOCTYPE_NEAR_BNO;
		}
		args.total = total;
		args.mod = args.minleft = args.alignment = args.wasdel =
			args.isfl = args.minalignslop = 0;
		args.minlen = args.maxlen = args.prod = 1;
		if ((error = xfs_alloc_vextent(&args)))
			goto done;
		/*
		 * Can't fail, the space was reserved.
		 */
		ASSERT(args.fsbno != NULLFSBLOCK);
		ASSERT(args.len == 1);
		*firstblock = args.fsbno;
		bp = xfs_btree_get_bufl(args.mp, tp, args.fsbno, 0);
		memcpy((char *)XFS_BUF_PTR(bp), ifp->if_u1.if_data,
			ifp->if_bytes);
		xfs_trans_log_buf(tp, bp, 0, ifp->if_bytes - 1);
		xfs_bmap_forkoff_reset(args.mp, ip, whichfork);
		xfs_idata_realloc(ip, -ifp->if_bytes, whichfork);
		xfs_iext_add(ifp, 0, 1);
		ep = xfs_iext_get_ext(ifp, 0);
		xfs_bmbt_set_allf(ep, 0, args.fsbno, 1, XFS_EXT_NORM);
		trace_xfs_bmap_post_update(ip, 0,
				whichfork == XFS_ATTR_FORK ? BMAP_ATTRFORK : 0,
				_THIS_IP_);
		XFS_IFORK_NEXT_SET(ip, whichfork, 1);
		ip->i_d.di_nblocks = 1;
		xfs_trans_mod_dquot_byino(tp, ip,
			XFS_TRANS_DQ_BCOUNT, 1L);
		flags |= xfs_ilog_fext(whichfork);
	} else {
		ASSERT(XFS_IFORK_NEXTENTS(ip, whichfork) == 0);
		xfs_bmap_forkoff_reset(ip->i_mount, ip, whichfork);
	}
	ifp->if_flags &= ~XFS_IFINLINE;
	ifp->if_flags |= XFS_IFEXTENTS;
	XFS_IFORK_FMT_SET(ip, whichfork, XFS_DINODE_FMT_EXTENTS);
	flags |= XFS_ILOG_CORE;
done:
	*logflagsp = flags;
	return error;
}

/*
 * Search the extent records for the entry containing block bno.
 * If bno lies in a hole, point to the next entry.  If bno lies
 * past eof, *eofp will be set, and *prevp will contain the last
 * entry (null if none).  Else, *lastxp will be set to the index
 * of the found entry; *gotp will contain the entry.
 */
STATIC xfs_bmbt_rec_host_t *		/* pointer to found extent entry */
xfs_bmap_search_multi_extents(
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_fileoff_t	bno,		/* block number searched for */
	int		*eofp,		/* out: end of file found */
	xfs_extnum_t	*lastxp,	/* out: last extent index */
	xfs_bmbt_irec_t	*gotp,		/* out: extent entry found */
	xfs_bmbt_irec_t	*prevp)		/* out: previous extent entry found */
{
	xfs_bmbt_rec_host_t *ep;		/* extent record pointer */
	xfs_extnum_t	lastx;		/* last extent index */

	/*
	 * Initialize the extent entry structure to catch access to
	 * uninitialized br_startblock field.
	 */
	gotp->br_startoff = 0xffa5a5a5a5a5a5a5LL;
	gotp->br_blockcount = 0xa55a5a5a5a5a5a5aLL;
	gotp->br_state = XFS_EXT_INVALID;
#if XFS_BIG_BLKNOS
	gotp->br_startblock = 0xffffa5a5a5a5a5a5LL;
#else
	gotp->br_startblock = 0xffffa5a5;
#endif
	prevp->br_startoff = NULLFILEOFF;

	ep = xfs_iext_bno_to_ext(ifp, bno, &lastx);
	if (lastx > 0) {
		xfs_bmbt_get_all(xfs_iext_get_ext(ifp, lastx - 1), prevp);
	}
	if (lastx < (ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t))) {
		xfs_bmbt_get_all(ep, gotp);
		*eofp = 0;
	} else {
		if (lastx > 0) {
			*gotp = *prevp;
		}
		*eofp = 1;
		ep = NULL;
	}
	*lastxp = lastx;
	return ep;
}

/*
 * Search the extents list for the inode, for the extent containing bno.
 * If bno lies in a hole, point to the next entry.  If bno lies past eof,
 * *eofp will be set, and *prevp will contain the last entry (null if none).
 * Else, *lastxp will be set to the index of the found
 * entry; *gotp will contain the entry.
 */
STATIC xfs_bmbt_rec_host_t *                 /* pointer to found extent entry */
xfs_bmap_search_extents(
	xfs_inode_t     *ip,            /* incore inode pointer */
	xfs_fileoff_t   bno,            /* block number searched for */
	int             fork,      	/* data or attr fork */
	int             *eofp,          /* out: end of file found */
	xfs_extnum_t    *lastxp,        /* out: last extent index */
	xfs_bmbt_irec_t *gotp,          /* out: extent entry found */
	xfs_bmbt_irec_t *prevp)         /* out: previous extent entry found */
{
	xfs_ifork_t	*ifp;		/* inode fork pointer */
	xfs_bmbt_rec_host_t  *ep;            /* extent record pointer */

	XFS_STATS_INC(xs_look_exlist);
	ifp = XFS_IFORK_PTR(ip, fork);

	ep = xfs_bmap_search_multi_extents(ifp, bno, eofp, lastxp, gotp, prevp);

	if (unlikely(!(gotp->br_startblock) && (*lastxp != NULLEXTNUM) &&
		     !(XFS_IS_REALTIME_INODE(ip) && fork == XFS_DATA_FORK))) {
		xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO,
				"Access to block zero in inode %llu "
				"start_block: %llx start_off: %llx "
				"blkcnt: %llx extent-state: %x lastx: %x\n",
			(unsigned long long)ip->i_ino,
			(unsigned long long)gotp->br_startblock,
			(unsigned long long)gotp->br_startoff,
			(unsigned long long)gotp->br_blockcount,
			gotp->br_state, *lastxp);
		*lastxp = NULLEXTNUM;
		*eofp = 1;
		return NULL;
	}
	return ep;
}

/*
 * Compute the worst-case number of indirect blocks that will be used
 * for ip's delayed extent of length "len".
 */
STATIC xfs_filblks_t
xfs_bmap_worst_indlen(
	xfs_inode_t	*ip,		/* incore inode pointer */
	xfs_filblks_t	len)		/* delayed extent length */
{
	int		level;		/* btree level number */
	int		maxrecs;	/* maximum record count at this level */
	xfs_mount_t	*mp;		/* mount structure */
	xfs_filblks_t	rval;		/* return value */

	mp = ip->i_mount;
	maxrecs = mp->m_bmap_dmxr[0];
	for (level = 0, rval = 0;
	     level < XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK);
	     level++) {
		len += maxrecs - 1;
		do_div(len, maxrecs);
		rval += len;
		if (len == 1)
			return rval + XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) -
				level - 1;
		if (level == 0)
			maxrecs = mp->m_bmap_dmxr[1];
	}
	return rval;
}

/*
 * Convert inode from non-attributed to attributed.
 * Must not be in a transaction, ip must not be locked.
 */
int						/* error code */
xfs_bmap_add_attrfork(
	xfs_inode_t		*ip,		/* incore inode pointer */
	int			size,		/* space new attribute needs */
	int			rsvd)		/* xact may use reserved blks */
{
	xfs_fsblock_t		firstblock;	/* 1st block/ag allocated */
	xfs_bmap_free_t		flist;		/* freed extent records */
	xfs_mount_t		*mp;		/* mount structure */
	xfs_trans_t		*tp;		/* transaction pointer */
	int			blks;		/* space reservation */
	int			version = 1;	/* superblock attr version */
	int			committed;	/* xaction was committed */
	int			logflags;	/* logging flags */
	int			error;		/* error return value */

	ASSERT(XFS_IFORK_Q(ip) == 0);
	ASSERT(ip->i_df.if_ext_max ==
	       XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t));

	mp = ip->i_mount;
	ASSERT(!XFS_NOT_DQATTACHED(mp, ip));
	tp = xfs_trans_alloc(mp, XFS_TRANS_ADDAFORK);
	blks = XFS_ADDAFORK_SPACE_RES(mp);
	if (rsvd)
		tp->t_flags |= XFS_TRANS_RESERVE;
	if ((error = xfs_trans_reserve(tp, blks, XFS_ADDAFORK_LOG_RES(mp), 0,
			XFS_TRANS_PERM_LOG_RES, XFS_ADDAFORK_LOG_COUNT)))
		goto error0;
	xfs_ilock(ip, XFS_ILOCK_EXCL);
	error = xfs_trans_reserve_quota_nblks(tp, ip, blks, 0, rsvd ?
			XFS_QMOPT_RES_REGBLKS | XFS_QMOPT_FORCE_RES :
			XFS_QMOPT_RES_REGBLKS);
	if (error) {
		xfs_iunlock(ip, XFS_ILOCK_EXCL);
		xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES);
		return error;
	}
	if (XFS_IFORK_Q(ip))
		goto error1;
	if (ip->i_d.di_aformat != XFS_DINODE_FMT_EXTENTS) {
		/*
		 * For inodes coming from pre-6.2 filesystems.
		 */
		ASSERT(ip->i_d.di_aformat == 0);
		ip->i_d.di_aformat = XFS_DINODE_FMT_EXTENTS;
	}
	ASSERT(ip->i_d.di_anextents == 0);

	xfs_trans_ijoin_ref(tp, ip, XFS_ILOCK_EXCL);
	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

	switch (ip->i_d.di_format) {
	case XFS_DINODE_FMT_DEV:
		ip->i_d.di_forkoff = roundup(sizeof(xfs_dev_t), 8) >> 3;
		break;
	case XFS_DINODE_FMT_UUID:
		ip->i_d.di_forkoff = roundup(sizeof(uuid_t), 8) >> 3;
		break;
	case XFS_DINODE_FMT_LOCAL:
	case XFS_DINODE_FMT_EXTENTS:
	case XFS_DINODE_FMT_BTREE:
		ip->i_d.di_forkoff = xfs_attr_shortform_bytesfit(ip, size);
		if (!ip->i_d.di_forkoff)
			ip->i_d.di_forkoff = xfs_default_attroffset(ip) >> 3;
		else if (mp->m_flags & XFS_MOUNT_ATTR2)
			version = 2;
		break;
	default:
		ASSERT(0);
		error = XFS_ERROR(EINVAL);
		goto error1;
	}
	ip->i_df.if_ext_max =
		XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t);
	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);
	ip->i_afp->if_flags = XFS_IFEXTENTS;
	logflags = 0;
	xfs_bmap_init(&flist, &firstblock);
	switch (ip->i_d.di_format) {
	case XFS_DINODE_FMT_LOCAL:
		error = xfs_bmap_add_attrfork_local(tp, ip, &firstblock, &flist,
			&logflags);
		break;
	case XFS_DINODE_FMT_EXTENTS:
		error = xfs_bmap_add_attrfork_extents(tp, ip, &firstblock,
			&flist, &logflags);
		break;
	case XFS_DINODE_FMT_BTREE:
		error = xfs_bmap_add_attrfork_btree(tp, ip, &firstblock, &flist,
			&logflags);
		break;
	default:
		error = 0;
		break;
	}
	if (logflags)
		xfs_trans_log_inode(tp, ip, logflags);
	if (error)
		goto error2;
	if (!xfs_sb_version_hasattr(&mp->m_sb) ||
	   (!xfs_sb_version_hasattr2(&mp->m_sb) && version == 2)) {
		__int64_t sbfields = 0;

		spin_lock(&mp->m_sb_lock);
		if (!xfs_sb_version_hasattr(&mp->m_sb)) {
			xfs_sb_version_addattr(&mp->m_sb);
			sbfields |= XFS_SB_VERSIONNUM;
		}
		if (!xfs_sb_version_hasattr2(&mp->m_sb) && version == 2) {
			xfs_sb_version_addattr2(&mp->m_sb);
			sbfields |= (XFS_SB_VERSIONNUM | XFS_SB_FEATURES2);
		}
		if (sbfields) {
			spin_unlock(&mp->m_sb_lock);
			xfs_mod_sb(tp, sbfields);
		} else
			spin_unlock(&mp->m_sb_lock);
	}
	if ((error = xfs_bmap_finish(&tp, &flist, &committed)))
		goto error2;
	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
	ASSERT(ip->i_df.if_ext_max ==
	       XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t));
	return error;
error2:
	xfs_bmap_cancel(&flist);
error1:
	xfs_iunlock(ip, XFS_ILOCK_EXCL);
error0:
	xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES|XFS_TRANS_ABORT);
	ASSERT(ip->i_df.if_ext_max ==
	       XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t));
	return error;
}

/*
 * Add the extent to the list of extents to be free at transaction end.
 * The list is maintained sorted (by block number).
 */
/* ARGSUSED */
void
xfs_bmap_add_free(
	xfs_fsblock_t		bno,		/* fs block number of extent */
	xfs_filblks_t		len,		/* length of extent */
	xfs_bmap_free_t		*flist,		/* list of extents */
	xfs_mount_t		*mp)		/* mount point structure */
{
	xfs_bmap_free_item_t	*cur;		/* current (next) element */
	xfs_bmap_free_item_t	*new;		/* new element */
	xfs_bmap_free_item_t	*prev;		/* previous element */
#ifdef DEBUG
	xfs_agnumber_t		agno;
	xfs_agblock_t		agbno;

	ASSERT(bno != NULLFSBLOCK);
	ASSERT(len > 0);
	ASSERT(len <= MAXEXTLEN);
	ASSERT(!isnullstartblock(bno));
	agno = XFS_FSB_TO_AGNO(mp, bno);
	agbno = XFS_FSB_TO_AGBNO(mp, bno);
	ASSERT(agno < mp->m_sb.sb_agcount);
	ASSERT(agbno < mp->m_sb.sb_agblocks);
	ASSERT(len < mp->m_sb.sb_agblocks);
	ASSERT(agbno + len <= mp->m_sb.sb_agblocks);
#endif
	ASSERT(xfs_bmap_free_item_zone != NULL);
	new = kmem_zone_alloc(xfs_bmap_free_item_zone, KM_SLEEP);
	new->xbfi_startblock = bno;
	new->xbfi_blockcount = (xfs_extlen_t)len;
	for (prev = NULL, cur = flist->xbf_first;
	     cur != NULL;
	     prev = cur, cur = cur->xbfi_next) {
		if (cur->xbfi_startblock >= bno)
			break;
	}
	if (prev)
		prev->xbfi_next = new;
	else
		flist->xbf_first = new;
	new->xbfi_next = cur;
	flist->xbf_count++;
}

/*
 * Compute and fill in the value of the maximum depth of a bmap btree
 * in this filesystem.  Done once, during mount.
 */
void
xfs_bmap_compute_maxlevels(
	xfs_mount_t	*mp,		/* file system mount structure */
	int		whichfork)	/* data or attr fork */
{
	int		level;		/* btree level */
	uint		maxblocks;	/* max blocks at this level */
	uint		maxleafents;	/* max leaf entries possible */
	int		maxrootrecs;	/* max records in root block */
	int		minleafrecs;	/* min records in leaf block */
	int		minnoderecs;	/* min records in node block */
	int		sz;		/* root block size */

	/*
	 * The maximum number of extents in a file, hence the maximum
	 * number of leaf entries, is controlled by the type of di_nextents
	 * (a signed 32-bit number, xfs_extnum_t), or by di_anextents
	 * (a signed 16-bit number, xfs_aextnum_t).
	 *
	 * Note that we can no longer assume that if we are in ATTR1 that
	 * the fork offset of all the inodes will be
	 * (xfs_default_attroffset(ip) >> 3) because we could have mounted
	 * with ATTR2 and then mounted back with ATTR1, keeping the
	 * di_forkoff's fixed but probably at various positions. Therefore,
	 * for both ATTR1 and ATTR2 we have to assume the worst case scenario
	 * of a minimum size available.
	 */
	if (whichfork == XFS_DATA_FORK) {
		maxleafents = MAXEXTNUM;
		sz = XFS_BMDR_SPACE_CALC(MINDBTPTRS);
	} else {
		maxleafents = MAXAEXTNUM;
		sz = XFS_BMDR_SPACE_CALC(MINABTPTRS);
	}
	maxrootrecs = xfs_bmdr_maxrecs(mp, sz, 0);
	minleafrecs = mp->m_bmap_dmnr[0];
	minnoderecs = mp->m_bmap_dmnr[1];
	maxblocks = (maxleafents + minleafrecs - 1) / minleafrecs;
	for (level = 1; maxblocks > 1; level++) {
		if (maxblocks <= maxrootrecs)
			maxblocks = 1;
		else
			maxblocks = (maxblocks + minnoderecs - 1) / minnoderecs;
	}
	mp->m_bm_maxlevels[whichfork] = level;
}

/*
 * Routine to be called at transaction's end by xfs_bmapi, xfs_bunmapi
 * caller.  Frees all the extents that need freeing, which must be done
 * last due to locking considerations.  We never free any extents in
 * the first transaction.  This is to allow the caller to make the first
 * transaction a synchronous one so that the pointers to the data being
 * broken in this transaction will be permanent before the data is actually
 * freed.  This is necessary to prevent blocks from being reallocated
 * and written to before the free and reallocation are actually permanent.
 * We do not just make the first transaction synchronous here, because
 * there are more efficient ways to gain the same protection in some cases
 * (see the file truncation code).
 *
 * Return 1 if the given transaction was committed and a new one
 * started, and 0 otherwise in the committed parameter.
 */
/*ARGSUSED*/
int						/* error */
xfs_bmap_finish(
	xfs_trans_t		**tp,		/* transaction pointer addr */
	xfs_bmap_free_t		*flist,		/* i/o: list extents to free */
	int			*committed)	/* xact committed or not */
{
	xfs_efd_log_item_t	*efd;		/* extent free data */
	xfs_efi_log_item_t	*efi;		/* extent free intention */
	int			error;		/* error return value */
	xfs_bmap_free_item_t	*free;		/* free extent item */
	unsigned int		logres;		/* new log reservation */
	unsigned int		logcount;	/* new log count */
	xfs_mount_t		*mp;		/* filesystem mount structure */
	xfs_bmap_free_item_t	*next;		/* next item on free list */
	xfs_trans_t		*ntp;		/* new transaction pointer */

	ASSERT((*tp)->t_flags & XFS_TRANS_PERM_LOG_RES);
	if (flist->xbf_count == 0) {
		*committed = 0;
		return 0;
	}
	ntp = *tp;
	efi = xfs_trans_get_efi(ntp, flist->xbf_count);
	for (free = flist->xbf_first; free; free = free->xbfi_next)
		xfs_trans_log_efi_extent(ntp, efi, free->xbfi_startblock,
			free->xbfi_blockcount);
	logres = ntp->t_log_res;
	logcount = ntp->t_log_count;
	ntp = xfs_trans_dup(*tp);
	error = xfs_trans_commit(*tp, 0);
	*tp = ntp;
	*committed = 1;
	/*
	 * We have a new transaction, so we should return committed=1,
	 * even though we're returning an error.
	 */
	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);

	if ((error = xfs_trans_reserve(ntp, 0, logres, 0, XFS_TRANS_PERM_LOG_RES,
			logcount)))
		return error;
	efd = xfs_trans_get_efd(ntp, efi, flist->xbf_count);
	for (free = flist->xbf_first; free != NULL; free = next) {
		next = free->xbfi_next;
		if ((error = xfs_free_extent(ntp, free->xbfi_startblock,
				free->xbfi_blockcount))) {
			/*
			 * The bmap free list will be cleaned up at a
			 * higher level.  The EFI will be canceled when
			 * this transaction is aborted.
			 * Need to force shutdown here to make sure it
			 * happens, since this transaction may not be
			 * dirty yet.
			 */
			mp = ntp->t_mountp;
			if (!XFS_FORCED_SHUTDOWN(mp))
				xfs_force_shutdown(mp,
						   (error == EFSCORRUPTED) ?
						   SHUTDOWN_CORRUPT_INCORE :
						   SHUTDOWN_META_IO_ERROR);
			return error;
		}
		xfs_trans_log_efd_extent(ntp, efd, free->xbfi_startblock,
			free->xbfi_blockcount);
		xfs_bmap_del_free(flist, NULL, free);
	}
	return 0;
}

/*
 * Free up any items left in the list.
 */
void
xfs_bmap_cancel(
	xfs_bmap_free_t		*flist)	/* list of bmap_free_items */
{
	xfs_bmap_free_item_t	*free;	/* free list item */
	xfs_bmap_free_item_t	*next;

	if (flist->xbf_count == 0)
		return;
	ASSERT(flist->xbf_first != NULL);
	for (free = flist->xbf_first; free; free = next) {
		next = free->xbfi_next;
		xfs_bmap_del_free(flist, NULL, free);
	}
	ASSERT(flist->xbf_count == 0);
}

/*
 * Returns the file-relative block number of the first unused block(s)
 * in the file with at least "len" logically contiguous blocks free.
 * This is the lowest-address hole if the file has holes, else the first block
 * past the end of file.
 * Return 0 if the file is currently local (in-inode).
 */
int						/* error */
xfs_bmap_first_unused(
	xfs_trans_t	*tp,			/* transaction pointer */
	xfs_inode_t	*ip,			/* incore inode */
	xfs_extlen_t	len,			/* size of hole to find */
	xfs_fileoff_t	*first_unused,		/* unused block */
	int		whichfork)		/* data or attr fork */
{
	int		error;			/* error return value */
	int		idx;			/* extent record index */
	xfs_ifork_t	*ifp;			/* inode fork pointer */
	xfs_fileoff_t	lastaddr;		/* last block number seen */
	xfs_fileoff_t	lowest;			/* lowest useful block */
	xfs_fileoff_t	max;			/* starting useful block */
	xfs_fileoff_t	off;			/* offset for this block */
	xfs_extnum_t	nextents;		/* number of extent entries */

	ASSERT(XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_BTREE ||
	       XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS ||
	       XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL);
	if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL) {
		*first_unused = 0;
		return 0;
	}
	ifp = XFS_IFORK_PTR(ip, whichfork);
	if (!(ifp->if_flags & XFS_IFEXTENTS) &&
	    (error = xfs_iread_extents(tp, ip, whichfork)))
		return error;
	lowest = *first_unused;
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	for (idx = 0, lastaddr = 0, max = lowest; idx < nextents; idx++) {
		xfs_bmbt_rec_host_t *ep = xfs_iext_get_ext(ifp, idx);
		off = xfs_bmbt_get_startoff(ep);
		/*
		 * See if the hole before this extent will work.
		 */
		if (off >= lowest + len && off - max >= len) {
			*first_unused = max;
			return 0;
		}
		lastaddr = off + xfs_bmbt_get_blockcount(ep);
		max = XFS_FILEOFF_MAX(lastaddr, lowest);
	}
	*first_unused = max;
	return 0;
}

/*
 * Returns the file-relative block number of the last block + 1 before
 * last_block (input value) in the file.
 * This is not based on i_size, it is based on the extent records.
 * Returns 0 for local files, as they do not have extent records.
 */
int						/* error */
xfs_bmap_last_before(
	xfs_trans_t	*tp,			/* transaction pointer */
	xfs_inode_t	*ip,			/* incore inode */
	xfs_fileoff_t	*last_block,		/* last block */
	int		whichfork)		/* data or attr fork */
{
	xfs_fileoff_t	bno;			/* input file offset */
	int		eof;			/* hit end of file */
	xfs_bmbt_rec_host_t *ep;		/* pointer to last extent */
	int		error;			/* error return value */
	xfs_bmbt_irec_t	got;			/* current extent value */
	xfs_ifork_t	*ifp;			/* inode fork pointer */
	xfs_extnum_t	lastx;			/* last extent used */
	xfs_bmbt_irec_t	prev;			/* previous extent value */

	if (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE &&
	    XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS &&
	    XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_LOCAL)
	       return XFS_ERROR(EIO);
	if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL) {
		*last_block = 0;
		return 0;
	}
	ifp = XFS_IFORK_PTR(ip, whichfork);
	if (!(ifp->if_flags & XFS_IFEXTENTS) &&
	    (error = xfs_iread_extents(tp, ip, whichfork)))
		return error;
	bno = *last_block - 1;
	ep = xfs_bmap_search_extents(ip, bno, whichfork, &eof, &lastx, &got,
		&prev);
	if (eof || xfs_bmbt_get_startoff(ep) > bno) {
		if (prev.br_startoff == NULLFILEOFF)
			*last_block = 0;
		else
			*last_block = prev.br_startoff + prev.br_blockcount;
	}
	/*
	 * Otherwise *last_block is already the right answer.
	 */
	return 0;
}

/*
 * Returns the file-relative block number of the first block past eof in
 * the file.  This is not based on i_size, it is based on the extent records.
 * Returns 0 for local files, as they do not have extent records.
 */
int						/* error */
xfs_bmap_last_offset(
	xfs_trans_t	*tp,			/* transaction pointer */
	xfs_inode_t	*ip,			/* incore inode */
	xfs_fileoff_t	*last_block,		/* last block */
	int		whichfork)		/* data or attr fork */
{
	xfs_bmbt_rec_host_t *ep;		/* pointer to last extent */
	int		error;			/* error return value */
	xfs_ifork_t	*ifp;			/* inode fork pointer */
	xfs_extnum_t	nextents;		/* number of extent entries */

	if (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE &&
	    XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS &&
	    XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_LOCAL)
	       return XFS_ERROR(EIO);
	if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL) {
		*last_block = 0;
		return 0;
	}
	ifp = XFS_IFORK_PTR(ip, whichfork);
	if (!(ifp->if_flags & XFS_IFEXTENTS) &&
	    (error = xfs_iread_extents(tp, ip, whichfork)))
		return error;
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	if (!nextents) {
		*last_block = 0;
		return 0;
	}
	ep = xfs_iext_get_ext(ifp, nextents - 1);
	*last_block = xfs_bmbt_get_startoff(ep) + xfs_bmbt_get_blockcount(ep);
	return 0;
}

/*
 * Returns whether the selected fork of the inode has exactly one
 * block or not.  For the data fork we check this matches di_size,
 * implying the file's range is 0..bsize-1.
 */
int					/* 1=>1 block, 0=>otherwise */
xfs_bmap_one_block(
	xfs_inode_t	*ip,		/* incore inode */
	int		whichfork)	/* data or attr fork */
{
	xfs_bmbt_rec_host_t *ep;	/* ptr to fork's extent */
	xfs_ifork_t	*ifp;		/* inode fork pointer */
	int		rval;		/* return value */
	xfs_bmbt_irec_t	s;		/* internal version of extent */

#ifndef DEBUG
	if (whichfork == XFS_DATA_FORK) {
		return ((ip->i_d.di_mode & S_IFMT) == S_IFREG) ?
			(ip->i_size == ip->i_mount->m_sb.sb_blocksize) :
			(ip->i_d.di_size == ip->i_mount->m_sb.sb_blocksize);
	}
#endif	/* !DEBUG */
	if (XFS_IFORK_NEXTENTS(ip, whichfork) != 1)
		return 0;
	if (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS)
		return 0;
	ifp = XFS_IFORK_PTR(ip, whichfork);
	ASSERT(ifp->if_flags & XFS_IFEXTENTS);
	ep = xfs_iext_get_ext(ifp, 0);
	xfs_bmbt_get_all(ep, &s);
	rval = s.br_startoff == 0 && s.br_blockcount == 1;
	if (rval && whichfork == XFS_DATA_FORK)
		ASSERT(ip->i_size == ip->i_mount->m_sb.sb_blocksize);
	return rval;
}

STATIC int
xfs_bmap_sanity_check(
	struct xfs_mount	*mp,
	struct xfs_buf		*bp,
	int			level)
{
	struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);

	if (be32_to_cpu(block->bb_magic) != XFS_BMAP_MAGIC ||
	    be16_to_cpu(block->bb_level) != level ||
	    be16_to_cpu(block->bb_numrecs) == 0 ||
	    be16_to_cpu(block->bb_numrecs) > mp->m_bmap_dmxr[level != 0])
		return 0;
	return 1;
}

/*
 * Read in the extents to if_extents.
 * All inode fields are set up by caller, we just traverse the btree
 * and copy the records in. If the file system cannot contain unwritten
 * extents, the records are checked for no "state" flags.
 */
int					/* error */
xfs_bmap_read_extents(
	xfs_trans_t		*tp,	/* transaction pointer */
	xfs_inode_t		*ip,	/* incore inode */
	int			whichfork) /* data or attr fork */
{
	struct xfs_btree_block	*block;	/* current btree block */
	xfs_fsblock_t		bno;	/* block # of "block" */
	xfs_buf_t		*bp;	/* buffer for "block" */
	int			error;	/* error return value */
	xfs_exntfmt_t		exntf;	/* XFS_EXTFMT_NOSTATE, if checking */
	xfs_extnum_t		i, j;	/* index into the extents list */
	xfs_ifork_t		*ifp;	/* fork structure */
	int			level;	/* btree level, for checking */
	xfs_mount_t		*mp;	/* file system mount structure */
	__be64			*pp;	/* pointer to block address */
	/* REFERENCED */
	xfs_extnum_t		room;	/* number of entries there's room for */

	bno = NULLFSBLOCK;
	mp = ip->i_mount;
	ifp = XFS_IFORK_PTR(ip, whichfork);
	exntf = (whichfork != XFS_DATA_FORK) ? XFS_EXTFMT_NOSTATE :
					XFS_EXTFMT_INODE(ip);
	block = ifp->if_broot;
	/*
	 * Root level must use BMAP_BROOT_PTR_ADDR macro to get ptr out.
	 */
	level = be16_to_cpu(block->bb_level);
	ASSERT(level > 0);
	pp = XFS_BMAP_BROOT_PTR_ADDR(mp, block, 1, ifp->if_broot_bytes);
	bno = be64_to_cpu(*pp);
	ASSERT(bno != NULLDFSBNO);
	ASSERT(XFS_FSB_TO_AGNO(mp, bno) < mp->m_sb.sb_agcount);
	ASSERT(XFS_FSB_TO_AGBNO(mp, bno) < mp->m_sb.sb_agblocks);
	/*
	 * Go down the tree until leaf level is reached, following the first
	 * pointer (leftmost) at each level.
	 */
	while (level-- > 0) {
		if ((error = xfs_btree_read_bufl(mp, tp, bno, 0, &bp,
				XFS_BMAP_BTREE_REF)))
			return error;
		block = XFS_BUF_TO_BLOCK(bp);
		XFS_WANT_CORRUPTED_GOTO(
			xfs_bmap_sanity_check(mp, bp, level),
			error0);
		if (level == 0)
			break;
		pp = XFS_BMBT_PTR_ADDR(mp, block, 1, mp->m_bmap_dmxr[1]);
		bno = be64_to_cpu(*pp);
		XFS_WANT_CORRUPTED_GOTO(XFS_FSB_SANITY_CHECK(mp, bno), error0);
		xfs_trans_brelse(tp, bp);
	}
	/*
	 * Here with bp and block set to the leftmost leaf node in the tree.
	 */
	room = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	i = 0;
	/*
	 * Loop over all leaf nodes.  Copy information to the extent records.
	 */
	for (;;) {
		xfs_bmbt_rec_t	*frp;
		xfs_fsblock_t	nextbno;
		xfs_extnum_t	num_recs;
		xfs_extnum_t	start;


		num_recs = xfs_btree_get_numrecs(block);
		if (unlikely(i + num_recs > room)) {
			ASSERT(i + num_recs <= room);
			xfs_warn(ip->i_mount,
				"corrupt dinode %Lu, (btree extents).",
				(unsigned long long) ip->i_ino);
			XFS_CORRUPTION_ERROR("xfs_bmap_read_extents(1)",
				XFS_ERRLEVEL_LOW, ip->i_mount, block);
			goto error0;
		}
		XFS_WANT_CORRUPTED_GOTO(
			xfs_bmap_sanity_check(mp, bp, 0),
			error0);
		/*
		 * Read-ahead the next leaf block, if any.
		 */
		nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);
		if (nextbno != NULLFSBLOCK)
			xfs_btree_reada_bufl(mp, nextbno, 1);
		/*
		 * Copy records into the extent records.
		 */
		frp = XFS_BMBT_REC_ADDR(mp, block, 1);
		start = i;
		for (j = 0; j < num_recs; j++, i++, frp++) {
			xfs_bmbt_rec_host_t *trp = xfs_iext_get_ext(ifp, i);
			trp->l0 = be64_to_cpu(frp->l0);
			trp->l1 = be64_to_cpu(frp->l1);
		}
		if (exntf == XFS_EXTFMT_NOSTATE) {
			/*
			 * Check all attribute bmap btree records and
			 * any "older" data bmap btree records for a
			 * set bit in the "extent flag" position.
			 */
			if (unlikely(xfs_check_nostate_extents(ifp,
					start, num_recs))) {
				XFS_ERROR_REPORT("xfs_bmap_read_extents(2)",
						 XFS_ERRLEVEL_LOW,
						 ip->i_mount);
				goto error0;
			}
		}
		xfs_trans_brelse(tp, bp);
		bno = nextbno;
		/*
		 * If we've reached the end, stop.
		 */
		if (bno == NULLFSBLOCK)
			break;
		if ((error = xfs_btree_read_bufl(mp, tp, bno, 0, &bp,
				XFS_BMAP_BTREE_REF)))
			return error;
		block = XFS_BUF_TO_BLOCK(bp);
	}
	ASSERT(i == (ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t)));
	ASSERT(i == XFS_IFORK_NEXTENTS(ip, whichfork));
	XFS_BMAP_TRACE_EXLIST(ip, i, whichfork);
	return 0;
error0:
	xfs_trans_brelse(tp, bp);
	return XFS_ERROR(EFSCORRUPTED);
}

#ifdef DEBUG
/*
 * Add bmap trace insert entries for all the contents of the extent records.
 */
void
xfs_bmap_trace_exlist(
	xfs_inode_t	*ip,		/* incore inode pointer */
	xfs_extnum_t	cnt,		/* count of entries in the list */
	int		whichfork,	/* data or attr fork */
	unsigned long	caller_ip)
{
	xfs_extnum_t	idx;		/* extent record index */
	xfs_ifork_t	*ifp;		/* inode fork pointer */
	int		state = 0;

	if (whichfork == XFS_ATTR_FORK)
		state |= BMAP_ATTRFORK;

	ifp = XFS_IFORK_PTR(ip, whichfork);
	ASSERT(cnt == (ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t)));
	for (idx = 0; idx < cnt; idx++)
		trace_xfs_extlist(ip, idx, whichfork, caller_ip);
}

/*
 * Validate that the bmbt_irecs being returned from bmapi are valid
 * given the callers original parameters.  Specifically check the
 * ranges of the returned irecs to ensure that they only extent beyond
 * the given parameters if the XFS_BMAPI_ENTIRE flag was set.
 */
STATIC void
xfs_bmap_validate_ret(
	xfs_fileoff_t		bno,
	xfs_filblks_t		len,
	int			flags,
	xfs_bmbt_irec_t		*mval,
	int			nmap,
	int			ret_nmap)
{
	int			i;		/* index to map values */

	ASSERT(ret_nmap <= nmap);

	for (i = 0; i < ret_nmap; i++) {
		ASSERT(mval[i].br_blockcount > 0);
		if (!(flags & XFS_BMAPI_ENTIRE)) {
			ASSERT(mval[i].br_startoff >= bno);
			ASSERT(mval[i].br_blockcount <= len);
			ASSERT(mval[i].br_startoff + mval[i].br_blockcount <=
			       bno + len);
		} else {
			ASSERT(mval[i].br_startoff < bno + len);
			ASSERT(mval[i].br_startoff + mval[i].br_blockcount >
			       bno);
		}
		ASSERT(i == 0 ||
		       mval[i - 1].br_startoff + mval[i - 1].br_blockcount ==
		       mval[i].br_startoff);
		if ((flags & XFS_BMAPI_WRITE) && !(flags & XFS_BMAPI_DELAY))
			ASSERT(mval[i].br_startblock != DELAYSTARTBLOCK &&
			       mval[i].br_startblock != HOLESTARTBLOCK);
		ASSERT(mval[i].br_state == XFS_EXT_NORM ||
		       mval[i].br_state == XFS_EXT_UNWRITTEN);
	}
}
#endif /* DEBUG */


/*
 * Map file blocks to filesystem blocks.
 * File range is given by the bno/len pair.
 * Adds blocks to file if a write ("flags & XFS_BMAPI_WRITE" set)
 * into a hole or past eof.
 * Only allocates blocks from a single allocation group,
 * to avoid locking problems.
 * The returned value in "firstblock" from the first call in a transaction
 * must be remembered and presented to subsequent calls in "firstblock".
 * An upper bound for the number of blocks to be allocated is supplied to
 * the first call in "total"; if no allocation group has that many free
 * blocks then the call will fail (return NULLFSBLOCK in "firstblock").
 */
int					/* error */
xfs_bmapi(
	xfs_trans_t	*tp,		/* transaction pointer */
	xfs_inode_t	*ip,		/* incore inode */
	xfs_fileoff_t	bno,		/* starting file offs. mapped */
	xfs_filblks_t	len,		/* length to map in file */
	int		flags,		/* XFS_BMAPI_... */
	xfs_fsblock_t	*firstblock,	/* first allocated block
					   controls a.g. for allocs */
	xfs_extlen_t	total,		/* total blocks needed */
	xfs_bmbt_irec_t	*mval,		/* output: map values */
	int		*nmap,		/* i/o: mval size/count */
	xfs_bmap_free_t	*flist)		/* i/o: list extents to free */
{
	xfs_fsblock_t	abno;		/* allocated block number */
	xfs_extlen_t	alen;		/* allocated extent length */
	xfs_fileoff_t	aoff;		/* allocated file offset */
	xfs_bmalloca_t	bma = { 0 };	/* args for xfs_bmap_alloc */
	xfs_btree_cur_t	*cur;		/* bmap btree cursor */
	xfs_fileoff_t	end;		/* end of mapped file region */
	int		eof;		/* we've hit the end of extents */
	xfs_bmbt_rec_host_t *ep;	/* extent record pointer */
	int		error;		/* error return */
	xfs_bmbt_irec_t	got;		/* current file extent record */
	xfs_ifork_t	*ifp;		/* inode fork pointer */
	xfs_extlen_t	indlen;		/* indirect blocks length */
	xfs_extnum_t	lastx;		/* last useful extent number */
	int		logflags;	/* flags for transaction logging */
	xfs_extlen_t	minleft;	/* min blocks left after allocation */
	xfs_extlen_t	minlen;		/* min allocation size */
	xfs_mount_t	*mp;		/* xfs mount structure */
	int		n;		/* current extent index */
	int		nallocs;	/* number of extents alloc'd */
	xfs_extnum_t	nextents;	/* number of extents in file */
	xfs_fileoff_t	obno;		/* old block number (offset) */
	xfs_bmbt_irec_t	prev;		/* previous file extent record */
	int		tmp_logflags;	/* temp flags holder */
	int		whichfork;	/* data or attr fork */
	char		inhole;		/* current location is hole in file */
	char		wasdelay;	/* old extent was delayed */
	char		wr;		/* this is a write request */
	char		rt;		/* this is a realtime file */
#ifdef DEBUG
	xfs_fileoff_t	orig_bno;	/* original block number value */
	int		orig_flags;	/* original flags arg value */
	xfs_filblks_t	orig_len;	/* original value of len arg */
	xfs_bmbt_irec_t	*orig_mval;	/* original value of mval */
	int		orig_nmap;	/* original value of *nmap */

	orig_bno = bno;
	orig_len = len;
	orig_flags = flags;
	orig_mval = mval;
	orig_nmap = *nmap;
#endif
	ASSERT(*nmap >= 1);
	ASSERT(*nmap <= XFS_BMAP_MAX_NMAP || !(flags & XFS_BMAPI_WRITE));
	whichfork = (flags & XFS_BMAPI_ATTRFORK) ?
		XFS_ATTR_FORK : XFS_DATA_FORK;
	mp = ip->i_mount;
	if (unlikely(XFS_TEST_ERROR(
	    (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS &&
	     XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE &&
	     XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_LOCAL),
	     mp, XFS_ERRTAG_BMAPIFORMAT, XFS_RANDOM_BMAPIFORMAT))) {
		XFS_ERROR_REPORT("xfs_bmapi", XFS_ERRLEVEL_LOW, mp);
		return XFS_ERROR(EFSCORRUPTED);
	}
	if (XFS_FORCED_SHUTDOWN(mp))
		return XFS_ERROR(EIO);
	rt = (whichfork == XFS_DATA_FORK) && XFS_IS_REALTIME_INODE(ip);
	ifp = XFS_IFORK_PTR(ip, whichfork);
	ASSERT(ifp->if_ext_max ==
	       XFS_IFORK_SIZE(ip, whichfork) / (uint)sizeof(xfs_bmbt_rec_t));
	if ((wr = (flags & XFS_BMAPI_WRITE)) != 0)
		XFS_STATS_INC(xs_blk_mapw);
	else
		XFS_STATS_INC(xs_blk_mapr);
	/*
	 * IGSTATE flag is used to combine extents which
	 * differ only due to the state of the extents.
	 * This technique is used from xfs_getbmap()
	 * when the caller does not wish to see the
	 * separation (which is the default).
	 *
	 * This technique is also used when writing a
	 * buffer which has been partially written,
	 * (usually by being flushed during a chunkread),
	 * to ensure one write takes place. This also
	 * prevents a change in the xfs inode extents at
	 * this time, intentionally. This change occurs
	 * on completion of the write operation, in
	 * xfs_strat_comp(), where the xfs_bmapi() call
	 * is transactioned, and the extents combined.
	 */
	if ((flags & XFS_BMAPI_IGSTATE) && wr)	/* if writing unwritten space */
		wr = 0;				/* no allocations are allowed */
	ASSERT(wr || !(flags & XFS_BMAPI_DELAY));
	logflags = 0;
	nallocs = 0;
	cur = NULL;
	if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL) {
		ASSERT(wr && tp);
		if ((error = xfs_bmap_local_to_extents(tp, ip,
				firstblock, total, &logflags, whichfork)))
			goto error0;
	}
	if (wr && *firstblock == NULLFSBLOCK) {
		if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_BTREE)
			minleft = be16_to_cpu(ifp->if_broot->bb_level) + 1;
		else
			minleft = 1;
	} else
		minleft = 0;
	if (!(ifp->if_flags & XFS_IFEXTENTS) &&
	    (error = xfs_iread_extents(tp, ip, whichfork)))
		goto error0;
	ep = xfs_bmap_search_extents(ip, bno, whichfork, &eof, &lastx, &got,
		&prev);
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	n = 0;
	end = bno + len;
	obno = bno;
	bma.ip = NULL;

	while (bno < end && n < *nmap) {
		/*
		 * Reading past eof, act as though there's a hole
		 * up to end.
		 */
		if (eof && !wr)
			got.br_startoff = end;
		inhole = eof || got.br_startoff > bno;
		wasdelay = wr && !inhole && !(flags & XFS_BMAPI_DELAY) &&
			isnullstartblock(got.br_startblock);
		/*
		 * First, deal with the hole before the allocated space
		 * that we found, if any.
		 */
		if (wr && (inhole || wasdelay)) {
			/*
			 * For the wasdelay case, we could also just
			 * allocate the stuff asked for in this bmap call
			 * but that wouldn't be as good.
			 */
			if (wasdelay) {
				alen = (xfs_extlen_t)got.br_blockcount;
				aoff = got.br_startoff;
				if (lastx != NULLEXTNUM && lastx) {
					ep = xfs_iext_get_ext(ifp, lastx - 1);
					xfs_bmbt_get_all(ep, &prev);
				}
			} else {
				alen = (xfs_extlen_t)
					XFS_FILBLKS_MIN(len, MAXEXTLEN);
				if (!eof)
					alen = (xfs_extlen_t)
						XFS_FILBLKS_MIN(alen,
							got.br_startoff - bno);
				aoff = bno;
			}
			minlen = (flags & XFS_BMAPI_CONTIG) ? alen : 1;
			if (flags & XFS_BMAPI_DELAY) {
				xfs_extlen_t	extsz;

				/* Figure out the extent size, adjust alen */
				extsz = xfs_get_extsz_hint(ip);
				if (extsz) {
					/*
					 * make sure we don't exceed a single
					 * extent length when we align the
					 * extent by reducing length we are
					 * going to allocate by the maximum
					 * amount extent size aligment may
					 * require.
					 */
					alen = XFS_FILBLKS_MIN(len,
						   MAXEXTLEN - (2 * extsz - 1));
					error = xfs_bmap_extsize_align(mp,
							&got, &prev, extsz,
							rt, eof,
							flags&XFS_BMAPI_DELAY,
							flags&XFS_BMAPI_CONVERT,
							&aoff, &alen);
					ASSERT(!error);
				}

				if (rt)
					extsz = alen / mp->m_sb.sb_rextsize;

				/*
				 * Make a transaction-less quota reservation for
				 * delayed allocation blocks. This number gets
				 * adjusted later.  We return if we haven't
				 * allocated blocks already inside this loop.
				 */
				error = xfs_trans_reserve_quota_nblks(
						NULL, ip, (long)alen, 0,
						rt ? XFS_QMOPT_RES_RTBLKS :
						     XFS_QMOPT_RES_REGBLKS);
				if (error) {
					if (n == 0) {
						*nmap = 0;
						ASSERT(cur == NULL);
						return error;
					}
					break;
				}

				/*
				 * Split changing sb for alen and indlen since
				 * they could be coming from different places.
				 */
				indlen = (xfs_extlen_t)
					xfs_bmap_worst_indlen(ip, alen);
				ASSERT(indlen > 0);

				if (rt) {
					error = xfs_mod_incore_sb(mp,
							XFS_SBS_FREXTENTS,
							-((int64_t)extsz), 0);
				} else {
					error = xfs_icsb_modify_counters(mp,
							XFS_SBS_FDBLOCKS,
							-((int64_t)alen), 0);
				}
				if (!error) {
					error = xfs_icsb_modify_counters(mp,
							XFS_SBS_FDBLOCKS,
							-((int64_t)indlen), 0);
					if (error && rt)
						xfs_mod_incore_sb(mp,
							XFS_SBS_FREXTENTS,
							(int64_t)extsz, 0);
					else if (error)
						xfs_icsb_modify_counters(mp,
							XFS_SBS_FDBLOCKS,
							(int64_t)alen, 0);
				}

				if (error) {
					if (XFS_IS_QUOTA_ON(mp))
						/* unreserve the blocks now */
						(void)
						xfs_trans_unreserve_quota_nblks(
							NULL, ip,
							(long)alen, 0, rt ?
							XFS_QMOPT_RES_RTBLKS :
							XFS_QMOPT_RES_REGBLKS);
					break;
				}

				ip->i_delayed_blks += alen;
				abno = nullstartblock(indlen);
			} else {
				/*
				 * If first time, allocate and fill in
				 * once-only bma fields.
				 */
				if (bma.ip == NULL) {
					bma.tp = tp;
					bma.ip = ip;
					bma.prevp = &prev;
					bma.gotp = &got;
					bma.total = total;
					bma.userdata = 0;
				}
				/* Indicate if this is the first user data
				 * in the file, or just any user data.
				 */
				if (!(flags & XFS_BMAPI_METADATA)) {
					bma.userdata = (aoff == 0) ?
						XFS_ALLOC_INITIAL_USER_DATA :
						XFS_ALLOC_USERDATA;
				}
				/*
				 * Fill in changeable bma fields.
				 */
				bma.eof = eof;
				bma.firstblock = *firstblock;
				bma.alen = alen;
				bma.off = aoff;
				bma.conv = !!(flags & XFS_BMAPI_CONVERT);
				bma.wasdel = wasdelay;
				bma.minlen = minlen;
				bma.low = flist->xbf_low;
				bma.minleft = minleft;
				/*
				 * Only want to do the alignment at the
				 * eof if it is userdata and allocation length
				 * is larger than a stripe unit.
				 */
				if (mp->m_dalign && alen >= mp->m_dalign &&
				    (!(flags & XFS_BMAPI_METADATA)) &&
				    (whichfork == XFS_DATA_FORK)) {
					if ((error = xfs_bmap_isaeof(ip, aoff,
							whichfork, &bma.aeof)))
						goto error0;
				} else
					bma.aeof = 0;
				/*
				 * Call allocator.
				 */
				if ((error = xfs_bmap_alloc(&bma)))
					goto error0;
				/*
				 * Copy out result fields.
				 */
				abno = bma.rval;
				if ((flist->xbf_low = bma.low))
					minleft = 0;
				alen = bma.alen;
				aoff = bma.off;
				ASSERT(*firstblock == NULLFSBLOCK ||
				       XFS_FSB_TO_AGNO(mp, *firstblock) ==
				       XFS_FSB_TO_AGNO(mp, bma.firstblock) ||
				       (flist->xbf_low &&
					XFS_FSB_TO_AGNO(mp, *firstblock) <
					XFS_FSB_TO_AGNO(mp, bma.firstblock)));
				*firstblock = bma.firstblock;
				if (cur)
					cur->bc_private.b.firstblock =
						*firstblock;
				if (abno == NULLFSBLOCK)
					break;
				if ((ifp->if_flags & XFS_IFBROOT) && !cur) {
					cur = xfs_bmbt_init_cursor(mp, tp,
						ip, whichfork);
					cur->bc_private.b.firstblock =
						*firstblock;
					cur->bc_private.b.flist = flist;
				}
				/*
				 * Bump the number of extents we've allocated
				 * in this call.
				 */
				nallocs++;
			}
			if (cur)
				cur->bc_private.b.flags =
					wasdelay ? XFS_BTCUR_BPRV_WASDEL : 0;
			got.br_startoff = aoff;
			got.br_startblock = abno;
			got.br_blockcount = alen;
			got.br_state = XFS_EXT_NORM;	/* assume normal */
			/*
			 * Determine state of extent, and the filesystem.
			 * A wasdelay extent has been initialized, so
			 * shouldn't be flagged as unwritten.
			 */
			if (wr && xfs_sb_version_hasextflgbit(&mp->m_sb)) {
				if (!wasdelay && (flags & XFS_BMAPI_PREALLOC))
					got.br_state = XFS_EXT_UNWRITTEN;
			}
			error = xfs_bmap_add_extent(ip, &lastx, &cur, &got,
				firstblock, flist, &tmp_logflags,
				whichfork);
			logflags |= tmp_logflags;
			if (error)
				goto error0;
			ep = xfs_iext_get_ext(ifp, lastx);
			nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
			xfs_bmbt_get_all(ep, &got);
			ASSERT(got.br_startoff <= aoff);
			ASSERT(got.br_startoff + got.br_blockcount >=
				aoff + alen);
#ifdef DEBUG
			if (flags & XFS_BMAPI_DELAY) {
				ASSERT(isnullstartblock(got.br_startblock));
				ASSERT(startblockval(got.br_startblock) > 0);
			}
			ASSERT(got.br_state == XFS_EXT_NORM ||
			       got.br_state == XFS_EXT_UNWRITTEN);
#endif
			/*
			 * Fall down into the found allocated space case.
			 */
		} else if (inhole) {
			/*
			 * Reading in a hole.
			 */
			mval->br_startoff = bno;
			mval->br_startblock = HOLESTARTBLOCK;
			mval->br_blockcount =
				XFS_FILBLKS_MIN(len, got.br_startoff - bno);
			mval->br_state = XFS_EXT_NORM;
			bno += mval->br_blockcount;
			len -= mval->br_blockcount;
			mval++;
			n++;
			continue;
		}
		/*
		 * Then deal with the allocated space we found.
		 */
		ASSERT(ep != NULL);
		if (!(flags & XFS_BMAPI_ENTIRE) &&
		    (got.br_startoff + got.br_blockcount > obno)) {
			if (obno > bno)
				bno = obno;
			ASSERT((bno >= obno) || (n == 0));
			ASSERT(bno < end);
			mval->br_startoff = bno;
			if (isnullstartblock(got.br_startblock)) {
				ASSERT(!wr || (flags & XFS_BMAPI_DELAY));
				mval->br_startblock = DELAYSTARTBLOCK;
			} else
				mval->br_startblock =
					got.br_startblock +
					(bno - got.br_startoff);
			/*
			 * Return the minimum of what we got and what we
			 * asked for for the length.  We can use the len
			 * variable here because it is modified below
			 * and we could have been there before coming
			 * here if the first part of the allocation
			 * didn't overlap what was asked for.
			 */
			mval->br_blockcount =
				XFS_FILBLKS_MIN(end - bno, got.br_blockcount -
					(bno - got.br_startoff));
			mval->br_state = got.br_state;
			ASSERT(mval->br_blockcount <= len);
		} else {
			*mval = got;
			if (isnullstartblock(mval->br_startblock)) {
				ASSERT(!wr || (flags & XFS_BMAPI_DELAY));
				mval->br_startblock = DELAYSTARTBLOCK;
			}
		}

		/*
		 * Check if writing previously allocated but
		 * unwritten extents.
		 */
		if (wr &&
		    ((mval->br_state == XFS_EXT_UNWRITTEN &&
		      ((flags & (XFS_BMAPI_PREALLOC|XFS_BMAPI_DELAY)) == 0)) ||
		     (mval->br_state == XFS_EXT_NORM &&
		      ((flags & (XFS_BMAPI_PREALLOC|XFS_BMAPI_CONVERT)) ==
				(XFS_BMAPI_PREALLOC|XFS_BMAPI_CONVERT))))) {
			/*
			 * Modify (by adding) the state flag, if writing.
			 */
			ASSERT(mval->br_blockcount <= len);
			if ((ifp->if_flags & XFS_IFBROOT) && !cur) {
				cur = xfs_bmbt_init_cursor(mp,
					tp, ip, whichfork);
				cur->bc_private.b.firstblock =
					*firstblock;
				cur->bc_private.b.flist = flist;
			}
			mval->br_state = (mval->br_state == XFS_EXT_UNWRITTEN)
						? XFS_EXT_NORM
						: XFS_EXT_UNWRITTEN;
			error = xfs_bmap_add_extent(ip, &lastx, &cur, mval,
				firstblock, flist, &tmp_logflags,
				whichfork);
			logflags |= tmp_logflags;
			if (error)
				goto error0;
			ep = xfs_iext_get_ext(ifp, lastx);
			nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
			xfs_bmbt_get_all(ep, &got);
			/*
			 * We may have combined previously unwritten
			 * space with written space, so generate
			 * another request.
			 */
			if (mval->br_blockcount < len)
				continue;
		}

		ASSERT((flags & XFS_BMAPI_ENTIRE) ||
		       ((mval->br_startoff + mval->br_blockcount) <= end));
		ASSERT((flags & XFS_BMAPI_ENTIRE) ||
		       (mval->br_blockcount <= len) ||
		       (mval->br_startoff < obno));
		bno = mval->br_startoff + mval->br_blockcount;
		len = end - bno;
		if (n > 0 && mval->br_startoff == mval[-1].br_startoff) {
			ASSERT(mval->br_startblock == mval[-1].br_startblock);
			ASSERT(mval->br_blockcount > mval[-1].br_blockcount);
			ASSERT(mval->br_state == mval[-1].br_state);
			mval[-1].br_blockcount = mval->br_blockcount;
			mval[-1].br_state = mval->br_state;
		} else if (n > 0 && mval->br_startblock != DELAYSTARTBLOCK &&
			   mval[-1].br_startblock != DELAYSTARTBLOCK &&
			   mval[-1].br_startblock != HOLESTARTBLOCK &&
			   mval->br_startblock ==
			   mval[-1].br_startblock + mval[-1].br_blockcount &&
			   ((flags & XFS_BMAPI_IGSTATE) ||
				mval[-1].br_state == mval->br_state)) {
			ASSERT(mval->br_startoff ==
			       mval[-1].br_startoff + mval[-1].br_blockcount);
			mval[-1].br_blockcount += mval->br_blockcount;
		} else if (n > 0 &&
			   mval->br_startblock == DELAYSTARTBLOCK &&
			   mval[-1].br_startblock == DELAYSTARTBLOCK &&
			   mval->br_startoff ==
			   mval[-1].br_startoff + mval[-1].br_blockcount) {
			mval[-1].br_blockcount += mval->br_blockcount;
			mval[-1].br_state = mval->br_state;
		} else if (!((n == 0) &&
			     ((mval->br_startoff + mval->br_blockcount) <=
			      obno))) {
			mval++;
			n++;
		}
		/*
		 * If we're done, stop now.  Stop when we've allocated
		 * XFS_BMAP_MAX_NMAP extents no matter what.  Otherwise
		 * the transaction may get too big.
		 */
		if (bno >= end || n >= *nmap || nallocs >= *nmap)
			break;
		/*
		 * Else go on to the next record.
		 */
		prev = got;
		if (++lastx < nextents) {
			ep = xfs_iext_get_ext(ifp, lastx);
			xfs_bmbt_get_all(ep, &got);
		} else {
			eof = 1;
		}
	}
	*nmap = n;
	/*
	 * Transform from btree to extents, give it cur.
	 */
	if (tp && XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_BTREE &&
	    XFS_IFORK_NEXTENTS(ip, whichfork) <= ifp->if_ext_max) {
		ASSERT(wr && cur);
		error = xfs_bmap_btree_to_extents(tp, ip, cur,
			&tmp_logflags, whichfork);
		logflags |= tmp_logflags;
		if (error)
			goto error0;
	}
	ASSERT(ifp->if_ext_max ==
	       XFS_IFORK_SIZE(ip, whichfork) / (uint)sizeof(xfs_bmbt_rec_t));
	ASSERT(XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE ||
	       XFS_IFORK_NEXTENTS(ip, whichfork) > ifp->if_ext_max);
	error = 0;
error0:
	/*
	 * Log everything.  Do this after conversion, there's no point in
	 * logging the extent records if we've converted to btree format.
	 */
	if ((logflags & xfs_ilog_fext(whichfork)) &&
	    XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS)
		logflags &= ~xfs_ilog_fext(whichfork);
	else if ((logflags & xfs_ilog_fbroot(whichfork)) &&
		 XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE)
		logflags &= ~xfs_ilog_fbroot(whichfork);
	/*
	 * Log whatever the flags say, even if error.  Otherwise we might miss
	 * detecting a case where the data is changed, there's an error,
	 * and it's not logged so we don't shutdown when we should.
	 */
	if (logflags) {
		ASSERT(tp && wr);
		xfs_trans_log_inode(tp, ip, logflags);
	}
	if (cur) {
		if (!error) {
			ASSERT(*firstblock == NULLFSBLOCK ||
			       XFS_FSB_TO_AGNO(mp, *firstblock) ==
			       XFS_FSB_TO_AGNO(mp,
				       cur->bc_private.b.firstblock) ||
			       (flist->xbf_low &&
				XFS_FSB_TO_AGNO(mp, *firstblock) <
				XFS_FSB_TO_AGNO(mp,
					cur->bc_private.b.firstblock)));
			*firstblock = cur->bc_private.b.firstblock;
		}
		xfs_btree_del_cursor(cur,
			error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
	}
	if (!error)
		xfs_bmap_validate_ret(orig_bno, orig_len, orig_flags, orig_mval,
			orig_nmap, *nmap);
	return error;
}

/*
 * Map file blocks to filesystem blocks, simple version.
 * One block (extent) only, read-only.
 * For flags, only the XFS_BMAPI_ATTRFORK flag is examined.
 * For the other flag values, the effect is as if XFS_BMAPI_METADATA
 * was set and all the others were clear.
 */
int						/* error */
xfs_bmapi_single(
	xfs_trans_t	*tp,		/* transaction pointer */
	xfs_inode_t	*ip,		/* incore inode */
	int		whichfork,	/* data or attr fork */
	xfs_fsblock_t	*fsb,		/* output: mapped block */
	xfs_fileoff_t	bno)		/* starting file offs. mapped */
{
	int		eof;		/* we've hit the end of extents */
	int		error;		/* error return */
	xfs_bmbt_irec_t	got;		/* current file extent record */
	xfs_ifork_t	*ifp;		/* inode fork pointer */
	xfs_extnum_t	lastx;		/* last useful extent number */
	xfs_bmbt_irec_t	prev;		/* previous file extent record */

	ifp = XFS_IFORK_PTR(ip, whichfork);
	if (unlikely(
	    XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE &&
	    XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS)) {
	       XFS_ERROR_REPORT("xfs_bmapi_single", XFS_ERRLEVEL_LOW,
				ip->i_mount);
	       return XFS_ERROR(EFSCORRUPTED);
	}
	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
		return XFS_ERROR(EIO);
	XFS_STATS_INC(xs_blk_mapr);
	if (!(ifp->if_flags & XFS_IFEXTENTS) &&
	    (error = xfs_iread_extents(tp, ip, whichfork)))
		return error;
	(void)xfs_bmap_search_extents(ip, bno, whichfork, &eof, &lastx, &got,
		&prev);
	/*
	 * Reading past eof, act as though there's a hole
	 * up to end.
	 */
	if (eof || got.br_startoff > bno) {
		*fsb = NULLFSBLOCK;
		return 0;
	}
	ASSERT(!isnullstartblock(got.br_startblock));
	ASSERT(bno < got.br_startoff + got.br_blockcount);
	*fsb = got.br_startblock + (bno - got.br_startoff);
	return 0;
}

/*
 * Unmap (remove) blocks from a file.
 * If nexts is nonzero then the number of extents to remove is limited to
 * that value.  If not all extents in the block range can be removed then
 * *done is set.
 */
int						/* error */
xfs_bunmapi(
	xfs_trans_t		*tp,		/* transaction pointer */
	struct xfs_inode	*ip,		/* incore inode */
	xfs_fileoff_t		bno,		/* starting offset to unmap */
	xfs_filblks_t		len,		/* length to unmap in file */
	int			flags,		/* misc flags */
	xfs_extnum_t		nexts,		/* number of extents max */
	xfs_fsblock_t		*firstblock,	/* first allocated block
						   controls a.g. for allocs */
	xfs_bmap_free_t		*flist,		/* i/o: list extents to free */
	int			*done)		/* set if not done yet */
{
	xfs_btree_cur_t		*cur;		/* bmap btree cursor */
	xfs_bmbt_irec_t		del;		/* extent being deleted */
	int			eof;		/* is deleting at eof */
	xfs_bmbt_rec_host_t	*ep;		/* extent record pointer */
	int			error;		/* error return value */
	xfs_extnum_t		extno;		/* extent number in list */
	xfs_bmbt_irec_t		got;		/* current extent record */
	xfs_ifork_t		*ifp;		/* inode fork pointer */
	int			isrt;		/* freeing in rt area */
	xfs_extnum_t		lastx;		/* last extent index used */
	int			logflags;	/* transaction logging flags */
	xfs_extlen_t		mod;		/* rt extent offset */
	xfs_mount_t		*mp;		/* mount structure */
	xfs_extnum_t		nextents;	/* number of file extents */
	xfs_bmbt_irec_t		prev;		/* previous extent record */
	xfs_fileoff_t		start;		/* first file offset deleted */
	int			tmp_logflags;	/* partial logging flags */
	int			wasdel;		/* was a delayed alloc extent */
	int			whichfork;	/* data or attribute fork */
	xfs_fsblock_t		sum;

	trace_xfs_bunmap(ip, bno, len, flags, _RET_IP_);

	whichfork = (flags & XFS_BMAPI_ATTRFORK) ?
		XFS_ATTR_FORK : XFS_DATA_FORK;
	ifp = XFS_IFORK_PTR(ip, whichfork);
	if (unlikely(
	    XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS &&
	    XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE)) {
		XFS_ERROR_REPORT("xfs_bunmapi", XFS_ERRLEVEL_LOW,
				 ip->i_mount);
		return XFS_ERROR(EFSCORRUPTED);
	}
	mp = ip->i_mount;
	if (XFS_FORCED_SHUTDOWN(mp))
		return XFS_ERROR(EIO);

	ASSERT(len > 0);
	ASSERT(nexts >= 0);
	ASSERT(ifp->if_ext_max ==
	       XFS_IFORK_SIZE(ip, whichfork) / (uint)sizeof(xfs_bmbt_rec_t));
	if (!(ifp->if_flags & XFS_IFEXTENTS) &&
	    (error = xfs_iread_extents(tp, ip, whichfork)))
		return error;
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	if (nextents == 0) {
		*done = 1;
		return 0;
	}
	XFS_STATS_INC(xs_blk_unmap);
	isrt = (whichfork == XFS_DATA_FORK) && XFS_IS_REALTIME_INODE(ip);
	start = bno;
	bno = start + len - 1;
	ep = xfs_bmap_search_extents(ip, bno, whichfork, &eof, &lastx, &got,
		&prev);

	/*
	 * Check to see if the given block number is past the end of the
	 * file, back up to the last block if so...
	 */
	if (eof) {
		ep = xfs_iext_get_ext(ifp, --lastx);
		xfs_bmbt_get_all(ep, &got);
		bno = got.br_startoff + got.br_blockcount - 1;
	}
	logflags = 0;
	if (ifp->if_flags & XFS_IFBROOT) {
		ASSERT(XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_BTREE);
		cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
		cur->bc_private.b.firstblock = *firstblock;
		cur->bc_private.b.flist = flist;
		cur->bc_private.b.flags = 0;
	} else
		cur = NULL;
	extno = 0;
	while (bno != (xfs_fileoff_t)-1 && bno >= start && lastx >= 0 &&
	       (nexts == 0 || extno < nexts)) {
		/*
		 * Is the found extent after a hole in which bno lives?
		 * Just back up to the previous extent, if so.
		 */
		if (got.br_startoff > bno) {
			if (--lastx < 0)
				break;
			ep = xfs_iext_get_ext(ifp, lastx);
			xfs_bmbt_get_all(ep, &got);
		}
		/*
		 * Is the last block of this extent before the range
		 * we're supposed to delete?  If so, we're done.
		 */
		bno = XFS_FILEOFF_MIN(bno,
			got.br_startoff + got.br_blockcount - 1);
		if (bno < start)
			break;
		/*
		 * Then deal with the (possibly delayed) allocated space
		 * we found.
		 */
		ASSERT(ep != NULL);
		del = got;
		wasdel = isnullstartblock(del.br_startblock);
		if (got.br_startoff < start) {
			del.br_startoff = start;
			del.br_blockcount -= start - got.br_startoff;
			if (!wasdel)
				del.br_startblock += start - got.br_startoff;
		}
		if (del.br_startoff + del.br_blockcount > bno + 1)
			del.br_blockcount = bno + 1 - del.br_startoff;
		sum = del.br_startblock + del.br_blockcount;
		if (isrt &&
		    (mod = do_mod(sum, mp->m_sb.sb_rextsize))) {
			/*
			 * Realtime extent not lined up at the end.
			 * The extent could have been split into written
			 * and unwritten pieces, or we could just be
			 * unmapping part of it.  But we can't really
			 * get rid of part of a realtime extent.
			 */
			if (del.br_state == XFS_EXT_UNWRITTEN ||
			    !xfs_sb_version_hasextflgbit(&mp->m_sb)) {
				/*
				 * This piece is unwritten, or we're not
				 * using unwritten extents.  Skip over it.
				 */
				ASSERT(bno >= mod);
				bno -= mod > del.br_blockcount ?
					del.br_blockcount : mod;
				if (bno < got.br_startoff) {
					if (--lastx >= 0)
						xfs_bmbt_get_all(xfs_iext_get_ext(
							ifp, lastx), &got);
				}
				continue;
			}
			/*
			 * It's written, turn it unwritten.
			 * This is better than zeroing it.
			 */
			ASSERT(del.br_state == XFS_EXT_NORM);
			ASSERT(xfs_trans_get_block_res(tp) > 0);
			/*
			 * If this spans a realtime extent boundary,
			 * chop it back to the start of the one we end at.
			 */
			if (del.br_blockcount > mod) {
				del.br_startoff += del.br_blockcount - mod;
				del.br_startblock += del.br_blockcount - mod;
				del.br_blockcount = mod;
			}
			del.br_state = XFS_EXT_UNWRITTEN;
			error = xfs_bmap_add_extent(ip, &lastx, &cur, &del,
				firstblock, flist, &logflags,
				XFS_DATA_FORK);
			if (error)
				goto error0;
			goto nodelete;
		}
		if (isrt && (mod = do_mod(del.br_startblock, mp->m_sb.sb_rextsize))) {
			/*
			 * Realtime extent is lined up at the end but not
			 * at the front.  We'll get rid of full extents if
			 * we can.
			 */
			mod = mp->m_sb.sb_rextsize - mod;
			if (del.br_blockcount > mod) {
				del.br_blockcount -= mod;
				del.br_startoff += mod;
				del.br_startblock += mod;
			} else if ((del.br_startoff == start &&
				    (del.br_state == XFS_EXT_UNWRITTEN ||
				     xfs_trans_get_block_res(tp) == 0)) ||
				   !xfs_sb_version_hasextflgbit(&mp->m_sb)) {
				/*
				 * Can't make it unwritten.  There isn't
				 * a full extent here so just skip it.
				 */
				ASSERT(bno >= del.br_blockcount);
				bno -= del.br_blockcount;
				if (got.br_startoff > bno) {
					if (--lastx >= 0) {
						ep = xfs_iext_get_ext(ifp,
								      lastx);
						xfs_bmbt_get_all(ep, &got);
					}
				}
				continue;
			} else if (del.br_state == XFS_EXT_UNWRITTEN) {
				/*
				 * This one is already unwritten.
				 * It must have a written left neighbor.
				 * Unwrite the killed part of that one and
				 * try again.
				 */
				ASSERT(lastx > 0);
				xfs_bmbt_get_all(xfs_iext_get_ext(ifp,
						lastx - 1), &prev);
				ASSERT(prev.br_state == XFS_EXT_NORM);
				ASSERT(!isnullstartblock(prev.br_startblock));
				ASSERT(del.br_startblock ==
				       prev.br_startblock + prev.br_blockcount);
				if (prev.br_startoff < start) {
					mod = start - prev.br_startoff;
					prev.br_blockcount -= mod;
					prev.br_startblock += mod;
					prev.br_startoff = start;
				}
				prev.br_state = XFS_EXT_UNWRITTEN;
				lastx--;
				error = xfs_bmap_add_extent(ip, &lastx, &cur,
					&prev, firstblock, flist, &logflags,
					XFS_DATA_FORK);
				if (error)
					goto error0;
				goto nodelete;
			} else {
				ASSERT(del.br_state == XFS_EXT_NORM);
				del.br_state = XFS_EXT_UNWRITTEN;
				error = xfs_bmap_add_extent(ip, &lastx, &cur,
					&del, firstblock, flist, &logflags,
					XFS_DATA_FORK);
				if (error)
					goto error0;
				goto nodelete;
			}
		}
		if (wasdel) {
			ASSERT(startblockval(del.br_startblock) > 0);
			/* Update realtime/data freespace, unreserve quota */
			if (isrt) {
				xfs_filblks_t rtexts;

				rtexts = XFS_FSB_TO_B(mp, del.br_blockcount);
				do_div(rtexts, mp->m_sb.sb_rextsize);
				xfs_mod_incore_sb(mp, XFS_SBS_FREXTENTS,
						(int64_t)rtexts, 0);
				(void)xfs_trans_reserve_quota_nblks(NULL,
					ip, -((long)del.br_blockcount), 0,
					XFS_QMOPT_RES_RTBLKS);
			} else {
				xfs_icsb_modify_counters(mp, XFS_SBS_FDBLOCKS,
						(int64_t)del.br_blockcount, 0);
				(void)xfs_trans_reserve_quota_nblks(NULL,
					ip, -((long)del.br_blockcount), 0,
					XFS_QMOPT_RES_REGBLKS);
			}
			ip->i_delayed_blks -= del.br_blockcount;
			if (cur)
				cur->bc_private.b.flags |=
					XFS_BTCUR_BPRV_WASDEL;
		} else if (cur)
			cur->bc_private.b.flags &= ~XFS_BTCUR_BPRV_WASDEL;
		/*
		 * If it's the case where the directory code is running
		 * with no block reservation, and the deleted block is in
		 * the middle of its extent, and the resulting insert
		 * of an extent would cause transformation to btree format,
		 * then reject it.  The calling code will then swap
		 * blocks around instead.
		 * We have to do this now, rather than waiting for the
		 * conversion to btree format, since the transaction
		 * will be dirty.
		 */
		if (!wasdel && xfs_trans_get_block_res(tp) == 0 &&
		    XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS &&
		    XFS_IFORK_NEXTENTS(ip, whichfork) >= ifp->if_ext_max &&
		    del.br_startoff > got.br_startoff &&
		    del.br_startoff + del.br_blockcount <
		    got.br_startoff + got.br_blockcount) {
			error = XFS_ERROR(ENOSPC);
			goto error0;
		}
		error = xfs_bmap_del_extent(ip, tp, &lastx, flist, cur, &del,
				&tmp_logflags, whichfork);
		logflags |= tmp_logflags;
		if (error)
			goto error0;
		bno = del.br_startoff - 1;
nodelete:
		/*
		 * If not done go on to the next (previous) record.
		 */
		if (bno != (xfs_fileoff_t)-1 && bno >= start) {
			if (lastx >= 0) {
				ep = xfs_iext_get_ext(ifp, lastx);
				if (xfs_bmbt_get_startoff(ep) > bno) {
					if (--lastx >= 0)
						ep = xfs_iext_get_ext(ifp,
								      lastx);
				}
				xfs_bmbt_get_all(ep, &got);
			}
			extno++;
		}
	}
	*done = bno == (xfs_fileoff_t)-1 || bno < start || lastx < 0;
	ASSERT(ifp->if_ext_max ==
	       XFS_IFORK_SIZE(ip, whichfork) / (uint)sizeof(xfs_bmbt_rec_t));
	/*
	 * Convert to a btree if necessary.
	 */
	if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS &&
	    XFS_IFORK_NEXTENTS(ip, whichfork) > ifp->if_ext_max) {
		ASSERT(cur == NULL);
		error = xfs_bmap_extents_to_btree(tp, ip, firstblock, flist,
			&cur, 0, &tmp_logflags, whichfork);
		logflags |= tmp_logflags;
		if (error)
			goto error0;
	}
	/*
	 * transform from btree to extents, give it cur
	 */
	else if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_BTREE &&
		 XFS_IFORK_NEXTENTS(ip, whichfork) <= ifp->if_ext_max) {
		ASSERT(cur != NULL);
		error = xfs_bmap_btree_to_extents(tp, ip, cur, &tmp_logflags,
			whichfork);
		logflags |= tmp_logflags;
		if (error)
			goto error0;
	}
	/*
	 * transform from extents to local?
	 */
	ASSERT(ifp->if_ext_max ==
	       XFS_IFORK_SIZE(ip, whichfork) / (uint)sizeof(xfs_bmbt_rec_t));
	error = 0;
error0:
	/*
	 * Log everything.  Do this after conversion, there's no point in
	 * logging the extent records if we've converted to btree format.
	 */
	if ((logflags & xfs_ilog_fext(whichfork)) &&
	    XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS)
		logflags &= ~xfs_ilog_fext(whichfork);
	else if ((logflags & xfs_ilog_fbroot(whichfork)) &&
		 XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE)
		logflags &= ~xfs_ilog_fbroot(whichfork);
	/*
	 * Log inode even in the error case, if the transaction
	 * is dirty we'll need to shut down the filesystem.
	 */
	if (logflags)
		xfs_trans_log_inode(tp, ip, logflags);
	if (cur) {
		if (!error) {
			*firstblock = cur->bc_private.b.firstblock;
			cur->bc_private.b.allocated = 0;
		}
		xfs_btree_del_cursor(cur,
			error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
	}
	return error;
}

/*
 * returns 1 for success, 0 if we failed to map the extent.
 */
STATIC int
xfs_getbmapx_fix_eof_hole(
	xfs_inode_t		*ip,		/* xfs incore inode pointer */
	struct getbmapx		*out,		/* output structure */
	int			prealloced,	/* this is a file with
						 * preallocated data space */
	__int64_t		end,		/* last block requested */
	xfs_fsblock_t		startblock)
{
	__int64_t		fixlen;
	xfs_mount_t		*mp;		/* file system mount point */
	xfs_ifork_t		*ifp;		/* inode fork pointer */
	xfs_extnum_t		lastx;		/* last extent pointer */
	xfs_fileoff_t		fileblock;

	if (startblock == HOLESTARTBLOCK) {
		mp = ip->i_mount;
		out->bmv_block = -1;
		fixlen = XFS_FSB_TO_BB(mp, XFS_B_TO_FSB(mp, ip->i_size));
		fixlen -= out->bmv_offset;
		if (prealloced && out->bmv_offset + out->bmv_length == end) {
			/* Came to hole at EOF. Trim it. */
			if (fixlen <= 0)
				return 0;
			out->bmv_length = fixlen;
		}
	} else {
		if (startblock == DELAYSTARTBLOCK)
			out->bmv_block = -2;
		else
			out->bmv_block = xfs_fsb_to_db(ip, startblock);
		fileblock = XFS_BB_TO_FSB(ip->i_mount, out->bmv_offset);
		ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
		if (xfs_iext_bno_to_ext(ifp, fileblock, &lastx) &&
		   (lastx == (ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t))-1))
			out->bmv_oflags |= BMV_OF_LAST;
	}

	return 1;
}

/*
 * Get inode's extents as described in bmv, and format for output.
 * Calls formatter to fill the user's buffer until all extents
 * are mapped, until the passed-in bmv->bmv_count slots have
 * been filled, or until the formatter short-circuits the loop,
 * if it is tracking filled-in extents on its own.
 */
int						/* error code */
xfs_getbmap(
	xfs_inode_t		*ip,
	struct getbmapx		*bmv,		/* user bmap structure */
	xfs_bmap_format_t	formatter,	/* format to user */
	void			*arg)		/* formatter arg */
{
	__int64_t		bmvend;		/* last block requested */
	int			error = 0;	/* return value */
	__int64_t		fixlen;		/* length for -1 case */
	int			i;		/* extent number */
	int			lock;		/* lock state */
	xfs_bmbt_irec_t		*map;		/* buffer for user's data */
	xfs_mount_t		*mp;		/* file system mount point */
	int			nex;		/* # of user extents can do */
	int			nexleft;	/* # of user extents left */
	int			subnex;		/* # of bmapi's can do */
	int			nmap;		/* number of map entries */
	struct getbmapx		*out;		/* output structure */
	int			whichfork;	/* data or attr fork */
	int			prealloced;	/* this is a file with
						 * preallocated data space */
	int			iflags;		/* interface flags */
	int			bmapi_flags;	/* flags for xfs_bmapi */
	int			cur_ext = 0;

	mp = ip->i_mount;
	iflags = bmv->bmv_iflags;
	whichfork = iflags & BMV_IF_ATTRFORK ? XFS_ATTR_FORK : XFS_DATA_FORK;

	if (whichfork == XFS_ATTR_FORK) {
		if (XFS_IFORK_Q(ip)) {
			if (ip->i_d.di_aformat != XFS_DINODE_FMT_EXTENTS &&
			    ip->i_d.di_aformat != XFS_DINODE_FMT_BTREE &&
			    ip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL)
				return XFS_ERROR(EINVAL);
		} else if (unlikely(
			   ip->i_d.di_aformat != 0 &&
			   ip->i_d.di_aformat != XFS_DINODE_FMT_EXTENTS)) {
			XFS_ERROR_REPORT("xfs_getbmap", XFS_ERRLEVEL_LOW,
					 ip->i_mount);
			return XFS_ERROR(EFSCORRUPTED);
		}

		prealloced = 0;
		fixlen = 1LL << 32;
	} else {
		if (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)
			return XFS_ERROR(EINVAL);

		if (xfs_get_extsz_hint(ip) ||
		    ip->i_d.di_flags & (XFS_DIFLAG_PREALLOC|XFS_DIFLAG_APPEND)){
			prealloced = 1;
			fixlen = XFS_MAXIOFFSET(mp);
		} else {
			prealloced = 0;
			fixlen = ip->i_size;
		}
	}

	if (bmv->bmv_length == -1) {
		fixlen = XFS_FSB_TO_BB(mp, XFS_B_TO_FSB(mp, fixlen));
		bmv->bmv_length =
			max_t(__int64_t, fixlen - bmv->bmv_offset, 0);
	} else if (bmv->bmv_length == 0) {
		bmv->bmv_entries = 0;
		return 0;
	} else if (bmv->bmv_length < 0) {
		return XFS_ERROR(EINVAL);
	}

	nex = bmv->bmv_count - 1;
	if (nex <= 0)
		return XFS_ERROR(EINVAL);
	bmvend = bmv->bmv_offset + bmv->bmv_length;


	if (bmv->bmv_count > ULONG_MAX / sizeof(struct getbmapx))
		return XFS_ERROR(ENOMEM);
	out = kmem_zalloc(bmv->bmv_count * sizeof(struct getbmapx), KM_MAYFAIL);
	if (!out)
		return XFS_ERROR(ENOMEM);

	xfs_ilock(ip, XFS_IOLOCK_SHARED);
	if (whichfork == XFS_DATA_FORK && !(iflags & BMV_IF_DELALLOC)) {
		if (ip->i_delayed_blks || ip->i_size > ip->i_d.di_size) {
			error = xfs_flush_pages(ip, 0, -1, 0, FI_REMAPF);
			if (error)
				goto out_unlock_iolock;
		}
		/*
		 * even after flushing the inode, there can still be delalloc
		 * blocks on the inode beyond EOF due to speculative
		 * preallocation. These are not removed until the release
		 * function is called or the inode is inactivated. Hence we
		 * cannot assert here that ip->i_delayed_blks == 0.
		 */
	}

	lock = xfs_ilock_map_shared(ip);

	/*
	 * Don't let nex be bigger than the number of extents
	 * we can have assuming alternating holes and real extents.
	 */
	if (nex > XFS_IFORK_NEXTENTS(ip, whichfork) * 2 + 1)
		nex = XFS_IFORK_NEXTENTS(ip, whichfork) * 2 + 1;

	bmapi_flags = xfs_bmapi_aflag(whichfork);
	if (!(iflags & BMV_IF_PREALLOC))
		bmapi_flags |= XFS_BMAPI_IGSTATE;

	/*
	 * Allocate enough space to handle "subnex" maps at a time.
	 */
	error = ENOMEM;
	subnex = 16;
	map = kmem_alloc(subnex * sizeof(*map), KM_MAYFAIL | KM_NOFS);
	if (!map)
		goto out_unlock_ilock;

	bmv->bmv_entries = 0;

	if (XFS_IFORK_NEXTENTS(ip, whichfork) == 0 &&
	    (whichfork == XFS_ATTR_FORK || !(iflags & BMV_IF_DELALLOC))) {
		error = 0;
		goto out_free_map;
	}

	nexleft = nex;

	do {
		nmap = (nexleft > subnex) ? subnex : nexleft;
		error = xfs_bmapi(NULL, ip, XFS_BB_TO_FSBT(mp, bmv->bmv_offset),
				  XFS_BB_TO_FSB(mp, bmv->bmv_length),
				  bmapi_flags, NULL, 0, map, &nmap,
				  NULL);
		if (error)
			goto out_free_map;
		ASSERT(nmap <= subnex);

		for (i = 0; i < nmap && nexleft && bmv->bmv_length; i++) {
			out[cur_ext].bmv_oflags = 0;
			if (map[i].br_state == XFS_EXT_UNWRITTEN)
				out[cur_ext].bmv_oflags |= BMV_OF_PREALLOC;
			else if (map[i].br_startblock == DELAYSTARTBLOCK)
				out[cur_ext].bmv_oflags |= BMV_OF_DELALLOC;
			out[cur_ext].bmv_offset =
				XFS_FSB_TO_BB(mp, map[i].br_startoff);
			out[cur_ext].bmv_length =
				XFS_FSB_TO_BB(mp, map[i].br_blockcount);
			out[cur_ext].bmv_unused1 = 0;
			out[cur_ext].bmv_unused2 = 0;
			ASSERT(((iflags & BMV_IF_DELALLOC) != 0) ||
			      (map[i].br_startblock != DELAYSTARTBLOCK));
                        if (map[i].br_startblock == HOLESTARTBLOCK &&
			    whichfork == XFS_ATTR_FORK) {
				/* came to the end of attribute fork */
				out[cur_ext].bmv_oflags |= BMV_OF_LAST;
				goto out_free_map;
			}

			if (!xfs_getbmapx_fix_eof_hole(ip, &out[cur_ext],
					prealloced, bmvend,
					map[i].br_startblock))
				goto out_free_map;

			bmv->bmv_offset =
				out[cur_ext].bmv_offset +
				out[cur_ext].bmv_length;
			bmv->bmv_length =
				max_t(__int64_t, 0, bmvend - bmv->bmv_offset);

			/*
			 * In case we don't want to return the hole,
			 * don't increase cur_ext so that we can reuse
			 * it in the next loop.
			 */
			if ((iflags & BMV_IF_NO_HOLES) &&
			    map[i].br_startblock == HOLESTARTBLOCK) {
				memset(&out[cur_ext], 0, sizeof(out[cur_ext]));
				continue;
			}

			nexleft--;
			bmv->bmv_entries++;
			cur_ext++;
		}
	} while (nmap && nexleft && bmv->bmv_length);

 out_free_map:
	kmem_free(map);
 out_unlock_ilock:
	xfs_iunlock_map_shared(ip, lock);
 out_unlock_iolock:
	xfs_iunlock(ip, XFS_IOLOCK_SHARED);

	for (i = 0; i < cur_ext; i++) {
		int full = 0;	/* user array is full */

		/* format results & advance arg */
		error = formatter(&arg, &out[i], &full);
		if (error || full)
			break;
	}

	kmem_free(out);
	return error;
}

/*
 * Check the last inode extent to determine whether this allocation will result
 * in blocks being allocated at the end of the file. When we allocate new data
 * blocks at the end of the file which do not start at the previous data block,
 * we will try to align the new blocks at stripe unit boundaries.
 */
STATIC int				/* error */
xfs_bmap_isaeof(
	xfs_inode_t	*ip,		/* incore inode pointer */
	xfs_fileoff_t   off,		/* file offset in fsblocks */
	int             whichfork,	/* data or attribute fork */
	char		*aeof)		/* return value */
{
	int		error;		/* error return value */
	xfs_ifork_t	*ifp;		/* inode fork pointer */
	xfs_bmbt_rec_host_t *lastrec;	/* extent record pointer */
	xfs_extnum_t	nextents;	/* number of file extents */
	xfs_bmbt_irec_t	s;		/* expanded extent record */

	ASSERT(whichfork == XFS_DATA_FORK);
	ifp = XFS_IFORK_PTR(ip, whichfork);
	if (!(ifp->if_flags & XFS_IFEXTENTS) &&
	    (error = xfs_iread_extents(NULL, ip, whichfork)))
		return error;
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	if (nextents == 0) {
		*aeof = 1;
		return 0;
	}
	/*
	 * Go to the last extent
	 */
	lastrec = xfs_iext_get_ext(ifp, nextents - 1);
	xfs_bmbt_get_all(lastrec, &s);
	/*
	 * Check we are allocating in the last extent (for delayed allocations)
	 * or past the last extent for non-delayed allocations.
	 */
	*aeof = (off >= s.br_startoff &&
		 off < s.br_startoff + s.br_blockcount &&
		 isnullstartblock(s.br_startblock)) ||
		off >= s.br_startoff + s.br_blockcount;
	return 0;
}

/*
 * Check if the endoff is outside the last extent. If so the caller will grow
 * the allocation to a stripe unit boundary.
 */
int					/* error */
xfs_bmap_eof(
	xfs_inode_t	*ip,		/* incore inode pointer */
	xfs_fileoff_t	endoff,		/* file offset in fsblocks */
	int		whichfork,	/* data or attribute fork */
	int		*eof)		/* result value */
{
	xfs_fsblock_t	blockcount;	/* extent block count */
	int		error;		/* error return value */
	xfs_ifork_t	*ifp;		/* inode fork pointer */
	xfs_bmbt_rec_host_t *lastrec;	/* extent record pointer */
	xfs_extnum_t	nextents;	/* number of file extents */
	xfs_fileoff_t	startoff;	/* extent starting file offset */

	ASSERT(whichfork == XFS_DATA_FORK);
	ifp = XFS_IFORK_PTR(ip, whichfork);
	if (!(ifp->if_flags & XFS_IFEXTENTS) &&
	    (error = xfs_iread_extents(NULL, ip, whichfork)))
		return error;
	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
	if (nextents == 0) {
		*eof = 1;
		return 0;
	}
	/*
	 * Go to the last extent
	 */
	lastrec = xfs_iext_get_ext(ifp, nextents - 1);
	startoff = xfs_bmbt_get_startoff(lastrec);
	blockcount = xfs_bmbt_get_blockcount(lastrec);
	*eof = endoff >= startoff + blockcount;
	return 0;
}

#ifdef DEBUG
STATIC struct xfs_buf *
xfs_bmap_get_bp(
	struct xfs_btree_cur	*cur,
	xfs_fsblock_t		bno)
{
	struct xfs_log_item_desc *lidp;
	int			i;

	if (!cur)
		return NULL;

	for (i = 0; i < XFS_BTREE_MAXLEVELS; i++) {
		if (!cur->bc_bufs[i])
			break;
		if (XFS_BUF_ADDR(cur->bc_bufs[i]) == bno)
			return cur->bc_bufs[i];
	}

	/* Chase down all the log items to see if the bp is there */
	list_for_each_entry(lidp, &cur->bc_tp->t_items, lid_trans) {
		struct xfs_buf_log_item	*bip;
		bip = (struct xfs_buf_log_item *)lidp->lid_item;
		if (bip->bli_item.li_type == XFS_LI_BUF &&
		    XFS_BUF_ADDR(bip->bli_buf) == bno)
			return bip->bli_buf;
	}

	return NULL;
}

STATIC void
xfs_check_block(
	struct xfs_btree_block	*block,
	xfs_mount_t		*mp,
	int			root,
	short			sz)
{
	int			i, j, dmxr;
	__be64			*pp, *thispa;	/* pointer to block address */
	xfs_bmbt_key_t		*prevp, *keyp;

	ASSERT(be16_to_cpu(block->bb_level) > 0);

	prevp = NULL;
	for( i = 1; i <= xfs_btree_get_numrecs(block); i++) {
		dmxr = mp->m_bmap_dmxr[0];
		keyp = XFS_BMBT_KEY_ADDR(mp, block, i);

		if (prevp) {
			ASSERT(be64_to_cpu(prevp->br_startoff) <
			       be64_to_cpu(keyp->br_startoff));
		}
		prevp = keyp;

		/*
		 * Compare the block numbers to see if there are dups.
		 */
		if (root)
			pp = XFS_BMAP_BROOT_PTR_ADDR(mp, block, i, sz);
		else
			pp = XFS_BMBT_PTR_ADDR(mp, block, i, dmxr);

		for (j = i+1; j <= be16_to_cpu(block->bb_numrecs); j++) {
			if (root)
				thispa = XFS_BMAP_BROOT_PTR_ADDR(mp, block, j, sz);
			else
				thispa = XFS_BMBT_PTR_ADDR(mp, block, j, dmxr);
			if (*thispa == *pp) {
				xfs_warn(mp, "%s: thispa(%d) == pp(%d) %Ld",
					__func__, j, i,
					(unsigned long long)be64_to_cpu(*thispa));
				panic("%s: ptrs are equal in node\n",
					__func__);
			}
		}
	}
}

/*
 * Check that the extents for the inode ip are in the right order in all
 * btree leaves.
 */

STATIC void
xfs_bmap_check_leaf_extents(
	xfs_btree_cur_t		*cur,	/* btree cursor or null */
	xfs_inode_t		*ip,		/* incore inode pointer */
	int			whichfork)	/* data or attr fork */
{
	struct xfs_btree_block	*block;	/* current btree block */
	xfs_fsblock_t		bno;	/* block # of "block" */
	xfs_buf_t		*bp;	/* buffer for "block" */
	int			error;	/* error return value */
	xfs_extnum_t		i=0, j;	/* index into the extents list */
	xfs_ifork_t		*ifp;	/* fork structure */
	int			level;	/* btree level, for checking */
	xfs_mount_t		*mp;	/* file system mount structure */
	__be64			*pp;	/* pointer to block address */
	xfs_bmbt_rec_t		*ep;	/* pointer to current extent */
	xfs_bmbt_rec_t		last = {0, 0}; /* last extent in prev block */
	xfs_bmbt_rec_t		*nextp;	/* pointer to next extent */
	int			bp_release = 0;

	if (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE) {
		return;
	}

	bno = NULLFSBLOCK;
	mp = ip->i_mount;
	ifp = XFS_IFORK_PTR(ip, whichfork);
	block = ifp->if_broot;
	/*
	 * Root level must use BMAP_BROOT_PTR_ADDR macro to get ptr out.
	 */
	level = be16_to_cpu(block->bb_level);
	ASSERT(level > 0);
	xfs_check_block(block, mp, 1, ifp->if_broot_bytes);
	pp = XFS_BMAP_BROOT_PTR_ADDR(mp, block, 1, ifp->if_broot_bytes);
	bno = be64_to_cpu(*pp);

	ASSERT(bno != NULLDFSBNO);
	ASSERT(XFS_FSB_TO_AGNO(mp, bno) < mp->m_sb.sb_agcount);
	ASSERT(XFS_FSB_TO_AGBNO(mp, bno) < mp->m_sb.sb_agblocks);

	/*
	 * Go down the tree until leaf level is reached, following the first
	 * pointer (leftmost) at each level.
	 */
	while (level-- > 0) {
		/* See if buf is in cur first */
		bp = xfs_bmap_get_bp(cur, XFS_FSB_TO_DADDR(mp, bno));
		if (bp) {
			bp_release = 0;
		} else {
			bp_release = 1;
		}
		if (!bp && (error = xfs_btree_read_bufl(mp, NULL, bno, 0, &bp,
				XFS_BMAP_BTREE_REF)))
			goto error_norelse;
		block = XFS_BUF_TO_BLOCK(bp);
		XFS_WANT_CORRUPTED_GOTO(
			xfs_bmap_sanity_check(mp, bp, level),
			error0);
		if (level == 0)
			break;

		/*
		 * Check this block for basic sanity (increasing keys and
		 * no duplicate blocks).
		 */

		xfs_check_block(block, mp, 0, 0);
		pp = XFS_BMBT_PTR_ADDR(mp, block, 1, mp->m_bmap_dmxr[1]);
		bno = be64_to_cpu(*pp);
		XFS_WANT_CORRUPTED_GOTO(XFS_FSB_SANITY_CHECK(mp, bno), error0);
		if (bp_release) {
			bp_release = 0;
			xfs_trans_brelse(NULL, bp);
		}
	}

	/*
	 * Here with bp and block set to the leftmost leaf node in the tree.
	 */
	i = 0;

	/*
	 * Loop over all leaf nodes checking that all extents are in the right order.
	 */
	for (;;) {
		xfs_fsblock_t	nextbno;
		xfs_extnum_t	num_recs;


		num_recs = xfs_btree_get_numrecs(block);

		/*
		 * Read-ahead the next leaf block, if any.
		 */

		nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);

		/*
		 * Check all the extents to make sure they are OK.
		 * If we had a previous block, the last entry should
		 * conform with the first entry in this one.
		 */

		ep = XFS_BMBT_REC_ADDR(mp, block, 1);
		if (i) {
			ASSERT(xfs_bmbt_disk_get_startoff(&last) +
			       xfs_bmbt_disk_get_blockcount(&last) <=
			       xfs_bmbt_disk_get_startoff(ep));
		}
		for (j = 1; j < num_recs; j++) {
			nextp = XFS_BMBT_REC_ADDR(mp, block, j + 1);
			ASSERT(xfs_bmbt_disk_get_startoff(ep) +
			       xfs_bmbt_disk_get_blockcount(ep) <=
			       xfs_bmbt_disk_get_startoff(nextp));
			ep = nextp;
		}

		last = *ep;
		i += num_recs;
		if (bp_release) {
			bp_release = 0;
			xfs_trans_brelse(NULL, bp);
		}
		bno = nextbno;
		/*
		 * If we've reached the end, stop.
		 */
		if (bno == NULLFSBLOCK)
			break;

		bp = xfs_bmap_get_bp(cur, XFS_FSB_TO_DADDR(mp, bno));
		if (bp) {
			bp_release = 0;
		} else {
			bp_release = 1;
		}
		if (!bp && (error = xfs_btree_read_bufl(mp, NULL, bno, 0, &bp,
				XFS_BMAP_BTREE_REF)))
			goto error_norelse;
		block = XFS_BUF_TO_BLOCK(bp);
	}
	if (bp_release) {
		bp_release = 0;
		xfs_trans_brelse(NULL, bp);
	}
	return;

error0:
	xfs_warn(mp, "%s: at error0", __func__);
	if (bp_release)
		xfs_trans_brelse(NULL, bp);
error_norelse:
	xfs_warn(mp, "%s: BAD after btree leaves for %d extents",
		__func__, i);
	panic("%s: CORRUPTED BTREE OR SOMETHING", __func__);
	return;
}
#endif

/*
 * Count fsblocks of the given fork.
 */
int						/* error */
xfs_bmap_count_blocks(
	xfs_trans_t		*tp,		/* transaction pointer */
	xfs_inode_t		*ip,		/* incore inode */
	int			whichfork,	/* data or attr fork */
	int			*count)		/* out: count of blocks */
{
	struct xfs_btree_block	*block;	/* current btree block */
	xfs_fsblock_t		bno;	/* block # of "block" */
	xfs_ifork_t		*ifp;	/* fork structure */
	int			level;	/* btree level, for checking */
	xfs_mount_t		*mp;	/* file system mount structure */
	__be64			*pp;	/* pointer to block address */

	bno = NULLFSBLOCK;
	mp = ip->i_mount;
	ifp = XFS_IFORK_PTR(ip, whichfork);
	if ( XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_EXTENTS ) {
		xfs_bmap_count_leaves(ifp, 0,
			ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t),
			count);
		return 0;
	}

	/*
	 * Root level must use BMAP_BROOT_PTR_ADDR macro to get ptr out.
	 */
	block = ifp->if_broot;
	level = be16_to_cpu(block->bb_level);
	ASSERT(level > 0);
	pp = XFS_BMAP_BROOT_PTR_ADDR(mp, block, 1, ifp->if_broot_bytes);
	bno = be64_to_cpu(*pp);
	ASSERT(bno != NULLDFSBNO);
	ASSERT(XFS_FSB_TO_AGNO(mp, bno) < mp->m_sb.sb_agcount);
	ASSERT(XFS_FSB_TO_AGBNO(mp, bno) < mp->m_sb.sb_agblocks);

	if (unlikely(xfs_bmap_count_tree(mp, tp, ifp, bno, level, count) < 0)) {
		XFS_ERROR_REPORT("xfs_bmap_count_blocks(2)", XFS_ERRLEVEL_LOW,
				 mp);
		return XFS_ERROR(EFSCORRUPTED);
	}

	return 0;
}

/*
 * Recursively walks each level of a btree
 * to count total fsblocks is use.
 */
STATIC int                                     /* error */
xfs_bmap_count_tree(
	xfs_mount_t     *mp,            /* file system mount point */
	xfs_trans_t     *tp,            /* transaction pointer */
	xfs_ifork_t	*ifp,		/* inode fork pointer */
	xfs_fsblock_t   blockno,	/* file system block number */
	int             levelin,	/* level in btree */
	int		*count)		/* Count of blocks */
{
	int			error;
	xfs_buf_t		*bp, *nbp;
	int			level = levelin;
	__be64			*pp;
	xfs_fsblock_t           bno = blockno;
	xfs_fsblock_t		nextbno;
	struct xfs_btree_block	*block, *nextblock;
	int			numrecs;

	if ((error = xfs_btree_read_bufl(mp, tp, bno, 0, &bp, XFS_BMAP_BTREE_REF)))
		return error;
	*count += 1;
	block = XFS_BUF_TO_BLOCK(bp);

	if (--level) {
		/* Not at node above leaves, count this level of nodes */
		nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);
		while (nextbno != NULLFSBLOCK) {
			if ((error = xfs_btree_read_bufl(mp, tp, nextbno,
				0, &nbp, XFS_BMAP_BTREE_REF)))
				return error;
			*count += 1;
			nextblock = XFS_BUF_TO_BLOCK(nbp);
			nextbno = be64_to_cpu(nextblock->bb_u.l.bb_rightsib);
			xfs_trans_brelse(tp, nbp);
		}

		/* Dive to the next level */
		pp = XFS_BMBT_PTR_ADDR(mp, block, 1, mp->m_bmap_dmxr[1]);
		bno = be64_to_cpu(*pp);
		if (unlikely((error =
		     xfs_bmap_count_tree(mp, tp, ifp, bno, level, count)) < 0)) {
			xfs_trans_brelse(tp, bp);
			XFS_ERROR_REPORT("xfs_bmap_count_tree(1)",
					 XFS_ERRLEVEL_LOW, mp);
			return XFS_ERROR(EFSCORRUPTED);
		}
		xfs_trans_brelse(tp, bp);
	} else {
		/* count all level 1 nodes and their leaves */
		for (;;) {
			nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);
			numrecs = be16_to_cpu(block->bb_numrecs);
			xfs_bmap_disk_count_leaves(mp, block, numrecs, count);
			xfs_trans_brelse(tp, bp);
			if (nextbno == NULLFSBLOCK)
				break;
			bno = nextbno;
			if ((error = xfs_btree_read_bufl(mp, tp, bno, 0, &bp,
				XFS_BMAP_BTREE_REF)))
				return error;
			*count += 1;
			block = XFS_BUF_TO_BLOCK(bp);
		}
	}
	return 0;
}

/*
 * Count leaf blocks given a range of extent records.
 */
STATIC void
xfs_bmap_count_leaves(
	xfs_ifork_t		*ifp,
	xfs_extnum_t		idx,
	int			numrecs,
	int			*count)
{
	int		b;

	for (b = 0; b < numrecs; b++) {
		xfs_bmbt_rec_host_t *frp = xfs_iext_get_ext(ifp, idx + b);
		*count += xfs_bmbt_get_blockcount(frp);
	}
}

/*
 * Count leaf blocks given a range of extent records originally
 * in btree format.
 */
STATIC void
xfs_bmap_disk_count_leaves(
	struct xfs_mount	*mp,
	struct xfs_btree_block	*block,
	int			numrecs,
	int			*count)
{
	int		b;
	xfs_bmbt_rec_t	*frp;

	for (b = 1; b <= numrecs; b++) {
		frp = XFS_BMBT_REC_ADDR(mp, block, b);
		*count += xfs_bmbt_disk_get_blockcount(frp);
	}
}

/*
 * dead simple method of punching delalyed allocation blocks from a range in
 * the inode. Walks a block at a time so will be slow, but is only executed in
 * rare error cases so the overhead is not critical. This will alays punch out
 * both the start and end blocks, even if the ranges only partially overlap
 * them, so it is up to the caller to ensure that partial blocks are not
 * passed in.
 */
int
xfs_bmap_punch_delalloc_range(
	struct xfs_inode	*ip,
	xfs_fileoff_t		start_fsb,
	xfs_fileoff_t		length)
{
	xfs_fileoff_t		remaining = length;
	int			error = 0;

	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));

	do {
		int		done;
		xfs_bmbt_irec_t	imap;
		int		nimaps = 1;
		xfs_fsblock_t	firstblock;
		xfs_bmap_free_t flist;

		/*
		 * Map the range first and check that it is a delalloc extent
		 * before trying to unmap the range. Otherwise we will be
		 * trying to remove a real extent (which requires a
		 * transaction) or a hole, which is probably a bad idea...
		 */
		error = xfs_bmapi(NULL, ip, start_fsb, 1,
				XFS_BMAPI_ENTIRE,  NULL, 0, &imap,
				&nimaps, NULL);

		if (error) {
			/* something screwed, just bail */
			if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
				xfs_alert(ip->i_mount,
			"Failed delalloc mapping lookup ino %lld fsb %lld.",
						ip->i_ino, start_fsb);
			}
			break;
		}
		if (!nimaps) {
			/* nothing there */
			goto next_block;
		}
		if (imap.br_startblock != DELAYSTARTBLOCK) {
			/* been converted, ignore */
			goto next_block;
		}
		WARN_ON(imap.br_blockcount == 0);

		/*
		 * Note: while we initialise the firstblock/flist pair, they
		 * should never be used because blocks should never be
		 * allocated or freed for a delalloc extent and hence we need
		 * don't cancel or finish them after the xfs_bunmapi() call.
		 */
		xfs_bmap_init(&flist, &firstblock);
		error = xfs_bunmapi(NULL, ip, start_fsb, 1, 0, 1, &firstblock,
					&flist, &done);
		if (error)
			break;

		ASSERT(!flist.xbf_count && !flist.xbf_first);
next_block:
		start_fsb++;
		remaining--;
	} while(remaining > 0);

	return error;
}