text: // SPDX-License-Identifier: GPL-2.0
  /*
   * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
   * All Rights Reserved.
   */
  #include "xfs.h"
  #include "xfs_fs.h"
  #include "xfs_shared.h"
  #include "xfs_format.h"
  #include "xfs_log_format.h"
  #include "xfs_trans_resv.h"
  #include "xfs_bit.h"
  #include "xfs_mount.h"
  #include "xfs_defer.h"
  #include "xfs_inode.h"
  #include "xfs_trans.h"
  #include "xfs_inode_item.h"
  #include "xfs_alloc.h"
  #include "xfs_btree.h"
  #include "xfs_bmap_btree.h"
  #include "xfs_bmap.h"
  #include "xfs_error.h"
  #include "xfs_quota.h"
  #include "xfs_trace.h"
  #include "xfs_cksum.h"
  #include "xfs_rmap.h"
  
  /*
   * Convert on-disk form of btree root to in-memory form.
   */
  void
  xfs_bmdr_to_bmbt(
  	struct xfs_inode	*ip,
  	xfs_bmdr_block_t	*dblock,
  	int			dblocklen,
  	struct xfs_btree_block	*rblock,
  	int			rblocklen)
  {
  	struct xfs_mount	*mp = ip->i_mount;
  	int			dmxr;
  	xfs_bmbt_key_t		*fkp;
  	__be64			*fpp;
  	xfs_bmbt_key_t		*tkp;
  	__be64			*tpp;
  
  	xfs_btree_init_block_int(mp, rblock, XFS_BUF_DADDR_NULL,
  				 XFS_BTNUM_BMAP, 0, 0, ip->i_ino,
  				 XFS_BTREE_LONG_PTRS);
  	rblock->bb_level = dblock->bb_level;
  	ASSERT(be16_to_cpu(rblock->bb_level) > 0);
  	rblock->bb_numrecs = dblock->bb_numrecs;
  	dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
  	fkp = XFS_BMDR_KEY_ADDR(dblock, 1);
  	tkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
  	fpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
  	tpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
  	dmxr = be16_to_cpu(dblock->bb_numrecs);
  	memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
  	memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
  }
  
  void
  xfs_bmbt_disk_get_all(
  	struct xfs_bmbt_rec	*rec,
  	struct xfs_bmbt_irec	*irec)
  {
  	uint64_t		l0 = get_unaligned_be64(&rec->l0);
  	uint64_t		l1 = get_unaligned_be64(&rec->l1);
  
  	irec->br_startoff = (l0 & xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
  	irec->br_startblock = ((l0 & xfs_mask64lo(9)) << 43) | (l1 >> 21);
  	irec->br_blockcount = l1 & xfs_mask64lo(21);
  	if (l0 >> (64 - BMBT_EXNTFLAG_BITLEN))
  		irec->br_state = XFS_EXT_UNWRITTEN;
  	else
  		irec->br_state = XFS_EXT_NORM;
  }
  
  /*
   * Extract the blockcount field from an on disk bmap extent record.
   */
  xfs_filblks_t
  xfs_bmbt_disk_get_blockcount(
  	xfs_bmbt_rec_t	*r)
  {
  	return (xfs_filblks_t)(be64_to_cpu(r->l1) & xfs_mask64lo(21));
  }
  
  /*
   * Extract the startoff field from a disk format bmap extent record.
   */
  xfs_fileoff_t
  xfs_bmbt_disk_get_startoff(
  	xfs_bmbt_rec_t	*r)
  {
  	return ((xfs_fileoff_t)be64_to_cpu(r->l0) &
  		 xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
  }
  
  /*
   * Set all the fields in a bmap extent record from the uncompressed form.
   */
  void
  xfs_bmbt_disk_set_all(
  	struct xfs_bmbt_rec	*r,
  	struct xfs_bmbt_irec	*s)
  {
  	int			extent_flag = (s->br_state != XFS_EXT_NORM);
  
  	ASSERT(s->br_state == XFS_EXT_NORM || s->br_state == XFS_EXT_UNWRITTEN);
  	ASSERT(!(s->br_startoff & xfs_mask64hi(64-BMBT_STARTOFF_BITLEN)));
  	ASSERT(!(s->br_blockcount & xfs_mask64hi(64-BMBT_BLOCKCOUNT_BITLEN)));
  	ASSERT(!(s->br_startblock & xfs_mask64hi(64-BMBT_STARTBLOCK_BITLEN)));
  
  	put_unaligned_be64(
  		((xfs_bmbt_rec_base_t)extent_flag << 63) |
  		 ((xfs_bmbt_rec_base_t)s->br_startoff << 9) |
  		 ((xfs_bmbt_rec_base_t)s->br_startblock >> 43), &r->l0);
  	put_unaligned_be64(
  		((xfs_bmbt_rec_base_t)s->br_startblock << 21) |
  		 ((xfs_bmbt_rec_base_t)s->br_blockcount &
  		  (xfs_bmbt_rec_base_t)xfs_mask64lo(21)), &r->l1);
  }
  
  /*
   * Convert in-memory form of btree root to on-disk form.
   */
  void
  xfs_bmbt_to_bmdr(
  	struct xfs_mount	*mp,
  	struct xfs_btree_block	*rblock,
  	int			rblocklen,
  	xfs_bmdr_block_t	*dblock,
  	int			dblocklen)
  {
  	int			dmxr;
  	xfs_bmbt_key_t		*fkp;
  	__be64			*fpp;
  	xfs_bmbt_key_t		*tkp;
  	__be64			*tpp;
  
  	if (xfs_sb_version_hascrc(&mp->m_sb)) {
  		ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_CRC_MAGIC));
  		ASSERT(uuid_equal(&rblock->bb_u.l.bb_uuid,
  		       &mp->m_sb.sb_meta_uuid));
  		ASSERT(rblock->bb_u.l.bb_blkno ==
  		       cpu_to_be64(XFS_BUF_DADDR_NULL));
  	} else
  		ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_MAGIC));
  	ASSERT(rblock->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK));
  	ASSERT(rblock->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK));
  	ASSERT(rblock->bb_level != 0);
  	dblock->bb_level = rblock->bb_level;
  	dblock->bb_numrecs = rblock->bb_numrecs;
  	dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
  	fkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
  	tkp = XFS_BMDR_KEY_ADDR(dblock, 1);
  	fpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
  	tpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
  	dmxr = be16_to_cpu(dblock->bb_numrecs);
  	memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
  	memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
  }
  
  STATIC struct xfs_btree_cur *
  xfs_bmbt_dup_cursor(
  	struct xfs_btree_cur	*cur)
  {
  	struct xfs_btree_cur	*new;
  
  	new = xfs_bmbt_init_cursor(cur->bc_mp, cur->bc_tp,
  			cur->bc_private.b.ip, cur->bc_private.b.whichfork);
  
  	/*
  	 * Copy the firstblock, dfops, and flags values,
  	 * since init cursor doesn't get them.
  	 */
  	new->bc_private.b.flags = cur->bc_private.b.flags;
  
  	return new;
  }
  
  STATIC void
  xfs_bmbt_update_cursor(
  	struct xfs_btree_cur	*src,
  	struct xfs_btree_cur	*dst)
  {
  	ASSERT((dst->bc_tp->t_firstblock != NULLFSBLOCK) ||
  	       (dst->bc_private.b.ip->i_d.di_flags & XFS_DIFLAG_REALTIME));
  
  	dst->bc_private.b.allocated += src->bc_private.b.allocated;
  	dst->bc_tp->t_firstblock = src->bc_tp->t_firstblock;
  
  	src->bc_private.b.allocated = 0;
  }
  
  STATIC int
  xfs_bmbt_alloc_block(
  	struct xfs_btree_cur	*cur,
  	union xfs_btree_ptr	*start,
  	union xfs_btree_ptr	*new,
  	int			*stat)
  {
  	xfs_alloc_arg_t		args;		/* block allocation args */
  	int			error;		/* error return value */
  
  	memset(&args, 0, sizeof(args));
  	args.tp = cur->bc_tp;
  	args.mp = cur->bc_mp;
  	args.fsbno = cur->bc_tp->t_firstblock;
  	xfs_rmap_ino_bmbt_owner(&args.oinfo, cur->bc_private.b.ip->i_ino,
  			cur->bc_private.b.whichfork);
  
  	if (args.fsbno == NULLFSBLOCK) {
  		args.fsbno = be64_to_cpu(start->l);
  		args.type = XFS_ALLOCTYPE_START_BNO;
  		/*
  		 * Make sure there is sufficient room left in the AG to
  		 * complete a full tree split for an extent insert.  If
  		 * we are converting the middle part of an extent then
  		 * we may need space for two tree splits.
  		 *
  		 * We are relying on the caller to make the correct block
  		 * reservation for this operation to succeed.  If the
  		 * reservation amount is insufficient then we may fail a
  		 * block allocation here and corrupt the filesystem.
  		 */
  		args.minleft = args.tp->t_blk_res;
  	} else if (cur->bc_tp->t_flags & XFS_TRANS_LOWMODE) {
  		args.type = XFS_ALLOCTYPE_START_BNO;
  	} else {
  		args.type = XFS_ALLOCTYPE_NEAR_BNO;
  	}
  
  	args.minlen = args.maxlen = args.prod = 1;
  	args.wasdel = cur->bc_private.b.flags & XFS_BTCUR_BPRV_WASDEL;
  	if (!args.wasdel && args.tp->t_blk_res == 0) {
  		error = -ENOSPC;
  		goto error0;
  	}
  	error = xfs_alloc_vextent(&args);
  	if (error)
  		goto error0;
  
  	if (args.fsbno == NULLFSBLOCK && args.minleft) {
  		/*
  		 * Could not find an AG with enough free space to satisfy
  		 * a full btree split.  Try again and if
  		 * successful activate the lowspace algorithm.
  		 */
  		args.fsbno = 0;
  		args.type = XFS_ALLOCTYPE_FIRST_AG;
  		error = xfs_alloc_vextent(&args);
  		if (error)
  			goto error0;
  		cur->bc_tp->t_flags |= XFS_TRANS_LOWMODE;
  	}
  	if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
  		*stat = 0;
  		return 0;
  	}
  
  	ASSERT(args.len == 1);
  	cur->bc_tp->t_firstblock = args.fsbno;
  	cur->bc_private.b.allocated++;
  	cur->bc_private.b.ip->i_d.di_nblocks++;
  	xfs_trans_log_inode(args.tp, cur->bc_private.b.ip, XFS_ILOG_CORE);
  	xfs_trans_mod_dquot_byino(args.tp, cur->bc_private.b.ip,
  			XFS_TRANS_DQ_BCOUNT, 1L);
  
  	new->l = cpu_to_be64(args.fsbno);
  
  	*stat = 1;
  	return 0;
  
   error0:
  	return error;
  }
  
  STATIC int
  xfs_bmbt_free_block(
  	struct xfs_btree_cur	*cur,
  	struct xfs_buf		*bp)
  {
  	struct xfs_mount	*mp = cur->bc_mp;
  	struct xfs_inode	*ip = cur->bc_private.b.ip;
  	struct xfs_trans	*tp = cur->bc_tp;
  	xfs_fsblock_t		fsbno = XFS_DADDR_TO_FSB(mp, XFS_BUF_ADDR(bp));
  	struct xfs_owner_info	oinfo;
  
  	xfs_rmap_ino_bmbt_owner(&oinfo, ip->i_ino, cur->bc_private.b.whichfork);
  	xfs_bmap_add_free(cur->bc_tp, fsbno, 1, &oinfo);
  	ip->i_d.di_nblocks--;
  
  	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
  	xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
  	return 0;
  }
  
  STATIC int
  xfs_bmbt_get_minrecs(
  	struct xfs_btree_cur	*cur,
  	int			level)
  {
  	if (level == cur->bc_nlevels - 1) {
  		struct xfs_ifork	*ifp;
  
  		ifp = XFS_IFORK_PTR(cur->bc_private.b.ip,
  				    cur->bc_private.b.whichfork);
  
  		return xfs_bmbt_maxrecs(cur->bc_mp,
  					ifp->if_broot_bytes, level == 0) / 2;
  	}
  
  	return cur->bc_mp->m_bmap_dmnr[level != 0];
  }
  
  int
  xfs_bmbt_get_maxrecs(
  	struct xfs_btree_cur	*cur,
  	int			level)
  {
  	if (level == cur->bc_nlevels - 1) {
  		struct xfs_ifork	*ifp;
  
  		ifp = XFS_IFORK_PTR(cur->bc_private.b.ip,
  				    cur->bc_private.b.whichfork);
  
  		return xfs_bmbt_maxrecs(cur->bc_mp,
  					ifp->if_broot_bytes, level == 0);
  	}
  
  	return cur->bc_mp->m_bmap_dmxr[level != 0];
  
  }
  
  /*
   * Get the maximum records we could store in the on-disk format.
   *
   * For non-root nodes this is equivalent to xfs_bmbt_get_maxrecs, but
   * for the root node this checks the available space in the dinode fork
   * so that we can resize the in-memory buffer to match it.  After a
   * resize to the maximum size this function returns the same value
   * as xfs_bmbt_get_maxrecs for the root node, too.
   */
  STATIC int
  xfs_bmbt_get_dmaxrecs(
  	struct xfs_btree_cur	*cur,
  	int			level)
  {
  	if (level != cur->bc_nlevels - 1)
  		return cur->bc_mp->m_bmap_dmxr[level != 0];
  	return xfs_bmdr_maxrecs(cur->bc_private.b.forksize, level == 0);
  }
  
  STATIC void
  xfs_bmbt_init_key_from_rec(
  	union xfs_btree_key	*key,
  	union xfs_btree_rec	*rec)
  {
  	key->bmbt.br_startoff =
  		cpu_to_be64(xfs_bmbt_disk_get_startoff(&rec->bmbt));
  }
  
  STATIC void
  xfs_bmbt_init_high_key_from_rec(
  	union xfs_btree_key	*key,
  	union xfs_btree_rec	*rec)
  {
  	key->bmbt.br_startoff = cpu_to_be64(
  			xfs_bmbt_disk_get_startoff(&rec->bmbt) +
  			xfs_bmbt_disk_get_blockcount(&rec->bmbt) - 1);
  }
  
  STATIC void
  xfs_bmbt_init_rec_from_cur(
  	struct xfs_btree_cur	*cur,
  	union xfs_btree_rec	*rec)
  {
  	xfs_bmbt_disk_set_all(&rec->bmbt, &cur->bc_rec.b);
  }
  
  STATIC void
  xfs_bmbt_init_ptr_from_cur(
  	struct xfs_btree_cur	*cur,
  	union xfs_btree_ptr	*ptr)
  {
  	ptr->l = 0;
  }
  
  STATIC int64_t
  xfs_bmbt_key_diff(
  	struct xfs_btree_cur	*cur,
  	union xfs_btree_key	*key)
  {
  	return (int64_t)be64_to_cpu(key->bmbt.br_startoff) -
  				      cur->bc_rec.b.br_startoff;
  }
  
  STATIC int64_t
  xfs_bmbt_diff_two_keys(
  	struct xfs_btree_cur	*cur,
  	union xfs_btree_key	*k1,
  	union xfs_btree_key	*k2)
  {
  	return (int64_t)be64_to_cpu(k1->bmbt.br_startoff) -
  			  be64_to_cpu(k2->bmbt.br_startoff);
  }
  
  static xfs_failaddr_t
  xfs_bmbt_verify(
  	struct xfs_buf		*bp)
  {
  	struct xfs_mount	*mp = bp->b_target->bt_mount;
  	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
  	xfs_failaddr_t		fa;
  	unsigned int		level;
  
  	switch (block->bb_magic) {
  	case cpu_to_be32(XFS_BMAP_CRC_MAGIC):
  		/*
  		 * XXX: need a better way of verifying the owner here. Right now
  		 * just make sure there has been one set.
  		 */
  		fa = xfs_btree_lblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
  		if (fa)
  			return fa;
  		/* fall through */
  	case cpu_to_be32(XFS_BMAP_MAGIC):
  		break;
  	default:
  		return __this_address;
  	}
  
  	/*
  	 * numrecs and level verification.
  	 *
  	 * We don't know what fork we belong to, so just verify that the level
  	 * is less than the maximum of the two. Later checks will be more
  	 * precise.
  	 */
  	level = be16_to_cpu(block->bb_level);
  	if (level > max(mp->m_bm_maxlevels[0], mp->m_bm_maxlevels[1]))
  		return __this_address;
  
  	return xfs_btree_lblock_verify(bp, mp->m_bmap_dmxr[level != 0]);
  }
  
  static void
  xfs_bmbt_read_verify(
  	struct xfs_buf	*bp)
  {
  	xfs_failaddr_t	fa;
  
  	if (!xfs_btree_lblock_verify_crc(bp))
  		xfs_verifier_error(bp, -EFSBADCRC, __this_address);
  	else {
  		fa = xfs_bmbt_verify(bp);
  		if (fa)
  			xfs_verifier_error(bp, -EFSCORRUPTED, fa);
  	}
  
  	if (bp->b_error)
  		trace_xfs_btree_corrupt(bp, _RET_IP_);
  }
  
  static void
  xfs_bmbt_write_verify(
  	struct xfs_buf	*bp)
  {
  	xfs_failaddr_t	fa;
  
  	fa = xfs_bmbt_verify(bp);
  	if (fa) {
  		trace_xfs_btree_corrupt(bp, _RET_IP_);
  		xfs_verifier_error(bp, -EFSCORRUPTED, fa);
  		return;
  	}
  	xfs_btree_lblock_calc_crc(bp);
  }
  
  const struct xfs_buf_ops xfs_bmbt_buf_ops = {
  	.name = "xfs_bmbt",
  	.verify_read = xfs_bmbt_read_verify,
  	.verify_write = xfs_bmbt_write_verify,
  	.verify_struct = xfs_bmbt_verify,
  };
  
  
  STATIC int
  xfs_bmbt_keys_inorder(
  	struct xfs_btree_cur	*cur,
  	union xfs_btree_key	*k1,
  	union xfs_btree_key	*k2)
  {
  	return be64_to_cpu(k1->bmbt.br_startoff) <
  		be64_to_cpu(k2->bmbt.br_startoff);
  }
  
  STATIC int
  xfs_bmbt_recs_inorder(
  	struct xfs_btree_cur	*cur,
  	union xfs_btree_rec	*r1,
  	union xfs_btree_rec	*r2)
  {
  	return xfs_bmbt_disk_get_startoff(&r1->bmbt) +
  		xfs_bmbt_disk_get_blockcount(&r1->bmbt) <=
  		xfs_bmbt_disk_get_startoff(&r2->bmbt);
  }
  
  static const struct xfs_btree_ops xfs_bmbt_ops = {
  	.rec_len		= sizeof(xfs_bmbt_rec_t),
  	.key_len		= sizeof(xfs_bmbt_key_t),
  
  	.dup_cursor		= xfs_bmbt_dup_cursor,
  	.update_cursor		= xfs_bmbt_update_cursor,
  	.alloc_block		= xfs_bmbt_alloc_block,
  	.free_block		= xfs_bmbt_free_block,
  	.get_maxrecs		= xfs_bmbt_get_maxrecs,
  	.get_minrecs		= xfs_bmbt_get_minrecs,
  	.get_dmaxrecs		= xfs_bmbt_get_dmaxrecs,
  	.init_key_from_rec	= xfs_bmbt_init_key_from_rec,
  	.init_high_key_from_rec	= xfs_bmbt_init_high_key_from_rec,
  	.init_rec_from_cur	= xfs_bmbt_init_rec_from_cur,
  	.init_ptr_from_cur	= xfs_bmbt_init_ptr_from_cur,
  	.key_diff		= xfs_bmbt_key_diff,
  	.diff_two_keys		= xfs_bmbt_diff_two_keys,
  	.buf_ops		= &xfs_bmbt_buf_ops,
  	.keys_inorder		= xfs_bmbt_keys_inorder,
  	.recs_inorder		= xfs_bmbt_recs_inorder,
  };
  
  /*
   * Allocate a new bmap btree cursor.
   */
  struct xfs_btree_cur *				/* new bmap btree cursor */
  xfs_bmbt_init_cursor(
  	struct xfs_mount	*mp,		/* file system mount point */
  	struct xfs_trans	*tp,		/* transaction pointer */
  	struct xfs_inode	*ip,		/* inode owning the btree */
  	int			whichfork)	/* data or attr fork */
  {
  	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, whichfork);
  	struct xfs_btree_cur	*cur;
  	ASSERT(whichfork != XFS_COW_FORK);
  
  	cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
  
  	cur->bc_tp = tp;
  	cur->bc_mp = mp;
  	cur->bc_nlevels = be16_to_cpu(ifp->if_broot->bb_level) + 1;
  	cur->bc_btnum = XFS_BTNUM_BMAP;
  	cur->bc_blocklog = mp->m_sb.sb_blocklog;
  	cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_bmbt_2);
  
  	cur->bc_ops = &xfs_bmbt_ops;
  	cur->bc_flags = XFS_BTREE_LONG_PTRS | XFS_BTREE_ROOT_IN_INODE;
  	if (xfs_sb_version_hascrc(&mp->m_sb))
  		cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
  
  	cur->bc_private.b.forksize = XFS_IFORK_SIZE(ip, whichfork);
  	cur->bc_private.b.ip = ip;
  	cur->bc_private.b.allocated = 0;
  	cur->bc_private.b.flags = 0;
  	cur->bc_private.b.whichfork = whichfork;
  
  	return cur;
  }
  
  /*
   * Calculate number of records in a bmap btree block.
   */
  int
  xfs_bmbt_maxrecs(
  	struct xfs_mount	*mp,
  	int			blocklen,
  	int			leaf)
  {
  	blocklen -= XFS_BMBT_BLOCK_LEN(mp);
  
  	if (leaf)
  		return blocklen / sizeof(xfs_bmbt_rec_t);
  	return blocklen / (sizeof(xfs_bmbt_key_t) + sizeof(xfs_bmbt_ptr_t));
  }
  
  /*
   * Calculate number of records in a bmap btree inode root.
   */
  int
  xfs_bmdr_maxrecs(
  	int			blocklen,
  	int			leaf)
  {
  	blocklen -= sizeof(xfs_bmdr_block_t);
  
  	if (leaf)
  		return blocklen / sizeof(xfs_bmdr_rec_t);
  	return blocklen / (sizeof(xfs_bmdr_key_t) + sizeof(xfs_bmdr_ptr_t));
  }
  
  /*
   * Change the owner of a btree format fork fo the inode passed in. Change it to
   * the owner of that is passed in so that we can change owners before or after
   * we switch forks between inodes. The operation that the caller is doing will
   * determine whether is needs to change owner before or after the switch.
   *
   * For demand paged transactional modification, the fork switch should be done
   * after reading in all the blocks, modifying them and pinning them in the
   * transaction. For modification when the buffers are already pinned in memory,
   * the fork switch can be done before changing the owner as we won't need to
   * validate the owner until the btree buffers are unpinned and writes can occur
   * again.
   *
   * For recovery based ownership change, there is no transactional context and
   * so a buffer list must be supplied so that we can record the buffers that we
   * modified for the caller to issue IO on.
   */
  int
  xfs_bmbt_change_owner(
  	struct xfs_trans	*tp,
  	struct xfs_inode	*ip,
  	int			whichfork,
  	xfs_ino_t		new_owner,
  	struct list_head	*buffer_list)
  {
  	struct xfs_btree_cur	*cur;
  	int			error;
  
  	ASSERT(tp || buffer_list);
  	ASSERT(!(tp && buffer_list));
  	if (whichfork == XFS_DATA_FORK)
  		ASSERT(ip->i_d.di_format == XFS_DINODE_FMT_BTREE);
  	else
  		ASSERT(ip->i_d.di_aformat == XFS_DINODE_FMT_BTREE);
  
  	cur = xfs_bmbt_init_cursor(ip->i_mount, tp, ip, whichfork);
  	if (!cur)
  		return -ENOMEM;
  	cur->bc_private.b.flags |= XFS_BTCUR_BPRV_INVALID_OWNER;
  
  	error = xfs_btree_change_owner(cur, new_owner, buffer_list);
  	xfs_btree_del_cursor(cur, error);
  	return error;
  }
  
  /* Calculate the bmap btree size for some records. */
  unsigned long long
  xfs_bmbt_calc_size(
  	struct xfs_mount	*mp,
  	unsigned long long	len)
  {
  	return xfs_btree_calc_size(mp->m_bmap_dmnr, len);
  }
  