fs/xfs/libxfs/xfs_ag.c - third_party/linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
  * Copyright (c) 2018 Red Hat, Inc.
  * All rights reserved.
  */

 #include "xfs.h"
 #include "xfs_fs.h"
 #include "xfs_shared.h"
 #include "xfs_format.h"
 #include "xfs_trans_resv.h"
 #include "xfs_sb.h"
 #include "xfs_mount.h"
 #include "xfs_btree.h"
 #include "xfs_alloc_btree.h"
 #include "xfs_rmap_btree.h"
 #include "xfs_alloc.h"
 #include "xfs_ialloc.h"
 #include "xfs_rmap.h"
 #include "xfs_ag.h"

 static struct xfs_buf *
 xfs_get_aghdr_buf(
 	struct xfs_mount	*mp,
 	xfs_daddr_t		blkno,
 	size_t			numblks,
 	int			flags,
 	const struct xfs_buf_ops *ops)
 {
 	struct xfs_buf		*bp;

 	bp = xfs_buf_get_uncached(mp->m_ddev_targp, numblks, flags);
 	if (!bp)
 		return NULL;

 	xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
 	bp->b_bn = blkno;
 	bp->b_maps[0].bm_bn = blkno;
 	bp->b_ops = ops;

 	return bp;
 }

 /*
  * Generic btree root block init function
  */
 static void
 xfs_btroot_init(
 	struct xfs_mount	*mp,
 	struct xfs_buf		*bp,
 	struct aghdr_init_data	*id)
 {
 	xfs_btree_init_block(mp, bp, id->type, 0, 0, id->agno, 0);
 }

 /*
  * Alloc btree root block init functions
  */
 static void
 xfs_bnoroot_init(
 	struct xfs_mount	*mp,
 	struct xfs_buf		*bp,
 	struct aghdr_init_data	*id)
 {
 	struct xfs_alloc_rec	*arec;

 	xfs_btree_init_block(mp, bp, XFS_BTNUM_BNO, 0, 1, id->agno, 0);
 	arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
 	arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
 	arec->ar_blockcount = cpu_to_be32(id->agsize -
 					  be32_to_cpu(arec->ar_startblock));
 }

 static void
 xfs_cntroot_init(
 	struct xfs_mount	*mp,
 	struct xfs_buf		*bp,
 	struct aghdr_init_data	*id)
 {
 	struct xfs_alloc_rec	*arec;

 	xfs_btree_init_block(mp, bp, XFS_BTNUM_CNT, 0, 1, id->agno, 0);
 	arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
 	arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
 	arec->ar_blockcount = cpu_to_be32(id->agsize -
 					  be32_to_cpu(arec->ar_startblock));
 }

 /*
  * Reverse map root block init
  */
 static void
 xfs_rmaproot_init(
 	struct xfs_mount	*mp,
 	struct xfs_buf		*bp,
 	struct aghdr_init_data	*id)
 {
 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
 	struct xfs_rmap_rec	*rrec;

 	xfs_btree_init_block(mp, bp, XFS_BTNUM_RMAP, 0, 4, id->agno, 0);

 	/*
 	 * mark the AG header regions as static metadata The BNO
 	 * btree block is the first block after the headers, so
 	 * it's location defines the size of region the static
 	 * metadata consumes.
 	 *
 	 * Note: unlike mkfs, we never have to account for log
 	 * space when growing the data regions
 	 */
 	rrec = XFS_RMAP_REC_ADDR(block, 1);
 	rrec->rm_startblock = 0;
 	rrec->rm_blockcount = cpu_to_be32(XFS_BNO_BLOCK(mp));
 	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_FS);
 	rrec->rm_offset = 0;

 	/* account freespace btree root blocks */
 	rrec = XFS_RMAP_REC_ADDR(block, 2);
 	rrec->rm_startblock = cpu_to_be32(XFS_BNO_BLOCK(mp));
 	rrec->rm_blockcount = cpu_to_be32(2);
 	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
 	rrec->rm_offset = 0;

 	/* account inode btree root blocks */
 	rrec = XFS_RMAP_REC_ADDR(block, 3);
 	rrec->rm_startblock = cpu_to_be32(XFS_IBT_BLOCK(mp));
 	rrec->rm_blockcount = cpu_to_be32(XFS_RMAP_BLOCK(mp) -
 					  XFS_IBT_BLOCK(mp));
 	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_INOBT);
 	rrec->rm_offset = 0;

 	/* account for rmap btree root */
 	rrec = XFS_RMAP_REC_ADDR(block, 4);
 	rrec->rm_startblock = cpu_to_be32(XFS_RMAP_BLOCK(mp));
 	rrec->rm_blockcount = cpu_to_be32(1);
 	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
 	rrec->rm_offset = 0;

 	/* account for refc btree root */
 	if (xfs_sb_version_hasreflink(&mp->m_sb)) {
 		rrec = XFS_RMAP_REC_ADDR(block, 5);
 		rrec->rm_startblock = cpu_to_be32(xfs_refc_block(mp));
 		rrec->rm_blockcount = cpu_to_be32(1);
 		rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_REFC);
 		rrec->rm_offset = 0;
 		be16_add_cpu(&block->bb_numrecs, 1);
 	}
 }

 /*
  * Initialise new secondary superblocks with the pre-grow geometry, but mark
  * them as "in progress" so we know they haven't yet been activated. This will
  * get cleared when the update with the new geometry information is done after
  * changes to the primary are committed. This isn't strictly necessary, but we
  * get it for free with the delayed buffer write lists and it means we can tell
  * if a grow operation didn't complete properly after the fact.
  */
 static void
 xfs_sbblock_init(
 	struct xfs_mount	*mp,
 	struct xfs_buf		*bp,
 	struct aghdr_init_data	*id)
 {
 	struct xfs_dsb		*dsb = XFS_BUF_TO_SBP(bp);

 	xfs_sb_to_disk(dsb, &mp->m_sb);
 	dsb->sb_inprogress = 1;
 }

 static void
 xfs_agfblock_init(
 	struct xfs_mount	*mp,
 	struct xfs_buf		*bp,
 	struct aghdr_init_data	*id)
 {
 	struct xfs_agf		*agf = XFS_BUF_TO_AGF(bp);
 	xfs_extlen_t		tmpsize;

 	agf->agf_magicnum = cpu_to_be32(XFS_AGF_MAGIC);
 	agf->agf_versionnum = cpu_to_be32(XFS_AGF_VERSION);
 	agf->agf_seqno = cpu_to_be32(id->agno);
 	agf->agf_length = cpu_to_be32(id->agsize);
 	agf->agf_roots[XFS_BTNUM_BNOi] = cpu_to_be32(XFS_BNO_BLOCK(mp));
 	agf->agf_roots[XFS_BTNUM_CNTi] = cpu_to_be32(XFS_CNT_BLOCK(mp));
 	agf->agf_levels[XFS_BTNUM_BNOi] = cpu_to_be32(1);
 	agf->agf_levels[XFS_BTNUM_CNTi] = cpu_to_be32(1);
 	if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
 		agf->agf_roots[XFS_BTNUM_RMAPi] =
 					cpu_to_be32(XFS_RMAP_BLOCK(mp));
 		agf->agf_levels[XFS_BTNUM_RMAPi] = cpu_to_be32(1);
 		agf->agf_rmap_blocks = cpu_to_be32(1);
 	}

 	agf->agf_flfirst = cpu_to_be32(1);
 	agf->agf_fllast = 0;
 	agf->agf_flcount = 0;
 	tmpsize = id->agsize - mp->m_ag_prealloc_blocks;
 	agf->agf_freeblks = cpu_to_be32(tmpsize);
 	agf->agf_longest = cpu_to_be32(tmpsize);
 	if (xfs_sb_version_hascrc(&mp->m_sb))
 		uuid_copy(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid);
 	if (xfs_sb_version_hasreflink(&mp->m_sb)) {
 		agf->agf_refcount_root = cpu_to_be32(
 				xfs_refc_block(mp));
 		agf->agf_refcount_level = cpu_to_be32(1);
 		agf->agf_refcount_blocks = cpu_to_be32(1);
 	}
 }

 static void
 xfs_agflblock_init(
 	struct xfs_mount	*mp,
 	struct xfs_buf		*bp,
 	struct aghdr_init_data	*id)
 {
 	struct xfs_agfl		*agfl = XFS_BUF_TO_AGFL(bp);
 	__be32			*agfl_bno;
 	int			bucket;

 	if (xfs_sb_version_hascrc(&mp->m_sb)) {
 		agfl->agfl_magicnum = cpu_to_be32(XFS_AGFL_MAGIC);
 		agfl->agfl_seqno = cpu_to_be32(id->agno);
 		uuid_copy(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid);
 	}

 	agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, bp);
 	for (bucket = 0; bucket < xfs_agfl_size(mp); bucket++)
 		agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK);
 }

 static void
 xfs_agiblock_init(
 	struct xfs_mount	*mp,
 	struct xfs_buf		*bp,
 	struct aghdr_init_data	*id)
 {
 	struct xfs_agi		*agi = XFS_BUF_TO_AGI(bp);
 	int			bucket;

 	agi->agi_magicnum = cpu_to_be32(XFS_AGI_MAGIC);
 	agi->agi_versionnum = cpu_to_be32(XFS_AGI_VERSION);
 	agi->agi_seqno = cpu_to_be32(id->agno);
 	agi->agi_length = cpu_to_be32(id->agsize);
 	agi->agi_count = 0;
 	agi->agi_root = cpu_to_be32(XFS_IBT_BLOCK(mp));
 	agi->agi_level = cpu_to_be32(1);
 	agi->agi_freecount = 0;
 	agi->agi_newino = cpu_to_be32(NULLAGINO);
 	agi->agi_dirino = cpu_to_be32(NULLAGINO);
 	if (xfs_sb_version_hascrc(&mp->m_sb))
 		uuid_copy(&agi->agi_uuid, &mp->m_sb.sb_meta_uuid);
 	if (xfs_sb_version_hasfinobt(&mp->m_sb)) {
 		agi->agi_free_root = cpu_to_be32(XFS_FIBT_BLOCK(mp));
 		agi->agi_free_level = cpu_to_be32(1);
 	}
 	for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
 		agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
 }

 typedef void (*aghdr_init_work_f)(struct xfs_mount *mp, struct xfs_buf *bp,
 				  struct aghdr_init_data *id);
 static int
 xfs_ag_init_hdr(
 	struct xfs_mount	*mp,
 	struct aghdr_init_data	*id,
 	aghdr_init_work_f	work,
 	const struct xfs_buf_ops *ops)

 {
 	struct xfs_buf		*bp;

 	bp = xfs_get_aghdr_buf(mp, id->daddr, id->numblks, 0, ops);
 	if (!bp)
 		return -ENOMEM;

 	(*work)(mp, bp, id);

 	xfs_buf_delwri_queue(bp, &id->buffer_list);
 	xfs_buf_relse(bp);
 	return 0;
 }

 struct xfs_aghdr_grow_data {
 	xfs_daddr_t		daddr;
 	size_t			numblks;
 	const struct xfs_buf_ops *ops;
 	aghdr_init_work_f	work;
 	xfs_btnum_t		type;
 	bool			need_init;
 };

 /*
  * Prepare new AG headers to be written to disk. We use uncached buffers here,
  * as it is assumed these new AG headers are currently beyond the currently
  * valid filesystem address space. Using cached buffers would trip over EOFS
  * corruption detection alogrithms in the buffer cache lookup routines.
  *
  * This is a non-transactional function, but the prepared buffers are added to a
  * delayed write buffer list supplied by the caller so they can submit them to
  * disk and wait on them as required.
  */
 int
 xfs_ag_init_headers(
 	struct xfs_mount	*mp,
 	struct aghdr_init_data	*id)

 {
 	struct xfs_aghdr_grow_data aghdr_data[] = {
 	{ /* SB */
 		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_SB_DADDR),
 		.numblks = XFS_FSS_TO_BB(mp, 1),
 		.ops = &xfs_sb_buf_ops,
 		.work = &xfs_sbblock_init,
 		.need_init = true
 	},
 	{ /* AGF */
 		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGF_DADDR(mp)),
 		.numblks = XFS_FSS_TO_BB(mp, 1),
 		.ops = &xfs_agf_buf_ops,
 		.work = &xfs_agfblock_init,
 		.need_init = true
 	},
 	{ /* AGFL */
 		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGFL_DADDR(mp)),
 		.numblks = XFS_FSS_TO_BB(mp, 1),
 		.ops = &xfs_agfl_buf_ops,
 		.work = &xfs_agflblock_init,
 		.need_init = true
 	},
 	{ /* AGI */
 		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGI_DADDR(mp)),
 		.numblks = XFS_FSS_TO_BB(mp, 1),
 		.ops = &xfs_agi_buf_ops,
 		.work = &xfs_agiblock_init,
 		.need_init = true
 	},
 	{ /* BNO root block */
 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_BNO_BLOCK(mp)),
 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
 		.ops = &xfs_allocbt_buf_ops,
 		.work = &xfs_bnoroot_init,
 		.need_init = true
 	},
 	{ /* CNT root block */
 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_CNT_BLOCK(mp)),
 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
 		.ops = &xfs_allocbt_buf_ops,
 		.work = &xfs_cntroot_init,
 		.need_init = true
 	},
 	{ /* INO root block */
 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_IBT_BLOCK(mp)),
 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
 		.ops = &xfs_inobt_buf_ops,
 		.work = &xfs_btroot_init,
 		.type = XFS_BTNUM_INO,
 		.need_init = true
 	},
 	{ /* FINO root block */
 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_FIBT_BLOCK(mp)),
 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
 		.ops = &xfs_inobt_buf_ops,
 		.work = &xfs_btroot_init,
 		.type = XFS_BTNUM_FINO,
 		.need_init =  xfs_sb_version_hasfinobt(&mp->m_sb)
 	},
 	{ /* RMAP root block */
 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_RMAP_BLOCK(mp)),
 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
 		.ops = &xfs_rmapbt_buf_ops,
 		.work = &xfs_rmaproot_init,
 		.need_init = xfs_sb_version_hasrmapbt(&mp->m_sb)
 	},
 	{ /* REFC root block */
 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, xfs_refc_block(mp)),
 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
 		.ops = &xfs_refcountbt_buf_ops,
 		.work = &xfs_btroot_init,
 		.type = XFS_BTNUM_REFC,
 		.need_init = xfs_sb_version_hasreflink(&mp->m_sb)
 	},
 	{ /* NULL terminating block */
 		.daddr = XFS_BUF_DADDR_NULL,
 	}
 	};
 	struct  xfs_aghdr_grow_data *dp;
 	int			error = 0;

 	/* Account for AG free space in new AG */
 	id->nfree += id->agsize - mp->m_ag_prealloc_blocks;
 	for (dp = &aghdr_data[0]; dp->daddr != XFS_BUF_DADDR_NULL; dp++) {
 		if (!dp->need_init)
 			continue;

 		id->daddr = dp->daddr;
 		id->numblks = dp->numblks;
 		id->type = dp->type;
 		error = xfs_ag_init_hdr(mp, id, dp->work, dp->ops);
 		if (error)
 			break;
 	}
 	return error;
 }

 /*
  * Extent the AG indicated by the @id by the length passed in
  */
 int
 xfs_ag_extend_space(
 	struct xfs_mount	*mp,
 	struct xfs_trans	*tp,
 	struct aghdr_init_data	*id,
 	xfs_extlen_t		len)
 {
 	struct xfs_owner_info	oinfo;
 	struct xfs_buf		*bp;
 	struct xfs_agi		*agi;
 	struct xfs_agf		*agf;
 	int			error;

 	/*
 	 * Change the agi length.
 	 */
 	error = xfs_ialloc_read_agi(mp, tp, id->agno, &bp);
 	if (error)
 		return error;

 	agi = XFS_BUF_TO_AGI(bp);
 	be32_add_cpu(&agi->agi_length, len);
 	ASSERT(id->agno == mp->m_sb.sb_agcount - 1 ||
 	       be32_to_cpu(agi->agi_length) == mp->m_sb.sb_agblocks);
 	xfs_ialloc_log_agi(tp, bp, XFS_AGI_LENGTH);

 	/*
 	 * Change agf length.
 	 */
 	error = xfs_alloc_read_agf(mp, tp, id->agno, 0, &bp);
 	if (error)
 		return error;

 	agf = XFS_BUF_TO_AGF(bp);
 	be32_add_cpu(&agf->agf_length, len);
 	ASSERT(agf->agf_length == agi->agi_length);
 	xfs_alloc_log_agf(tp, bp, XFS_AGF_LENGTH);

 	/*
 	 * Free the new space.
 	 *
 	 * XFS_RMAP_OWN_NULL is used here to tell the rmap btree that
 	 * this doesn't actually exist in the rmap btree.
 	 */
 	xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_NULL);
 	error = xfs_rmap_free(tp, bp, id->agno,
 				be32_to_cpu(agf->agf_length) - len,
 				len, &oinfo);
 	if (error)
 		return error;

 	return  xfs_free_extent(tp, XFS_AGB_TO_FSB(mp, id->agno,
 					be32_to_cpu(agf->agf_length) - len),
 				len, &oinfo, XFS_AG_RESV_NONE);
 }
	/* SPDX-License-Identifier: GPL-2.0 */
	/*
	* Copyright (c) 2000-2005 Silicon Graphics, Inc.
	* Copyright (c) 2018 Red Hat, Inc.
	* All rights reserved.
	*/

	#include "xfs.h"
	#include "xfs_fs.h"
	#include "xfs_shared.h"
	#include "xfs_format.h"
	#include "xfs_trans_resv.h"
	#include "xfs_sb.h"
	#include "xfs_mount.h"
	#include "xfs_btree.h"
	#include "xfs_alloc_btree.h"
	#include "xfs_rmap_btree.h"
	#include "xfs_alloc.h"
	#include "xfs_ialloc.h"
	#include "xfs_rmap.h"
	#include "xfs_ag.h"

	static struct xfs_buf *
	xfs_get_aghdr_buf(
	struct xfs_mount *mp,
	xfs_daddr_t blkno,
	size_t numblks,
	int flags,
	const struct xfs_buf_ops *ops)
	{
	struct xfs_buf *bp;

	bp = xfs_buf_get_uncached(mp->m_ddev_targp, numblks, flags);
	if (!bp)
	return NULL;

	xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
	bp->b_bn = blkno;
	bp->b_maps[0].bm_bn = blkno;
	bp->b_ops = ops;

	return bp;
	}

	/*
	* Generic btree root block init function
	*/
	static void
	xfs_btroot_init(
	struct xfs_mount *mp,
	struct xfs_buf *bp,
	struct aghdr_init_data *id)
	{
	xfs_btree_init_block(mp, bp, id->type, 0, 0, id->agno, 0);
	}

	/*
	* Alloc btree root block init functions
	*/
	static void
	xfs_bnoroot_init(
	struct xfs_mount *mp,
	struct xfs_buf *bp,
	struct aghdr_init_data *id)
	{
	struct xfs_alloc_rec *arec;

	xfs_btree_init_block(mp, bp, XFS_BTNUM_BNO, 0, 1, id->agno, 0);
	arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
	arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
	arec->ar_blockcount = cpu_to_be32(id->agsize -
	be32_to_cpu(arec->ar_startblock));
	}

	static void
	xfs_cntroot_init(
	struct xfs_mount *mp,
	struct xfs_buf *bp,
	struct aghdr_init_data *id)
	{
	struct xfs_alloc_rec *arec;

	xfs_btree_init_block(mp, bp, XFS_BTNUM_CNT, 0, 1, id->agno, 0);
	arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
	arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
	arec->ar_blockcount = cpu_to_be32(id->agsize -
	be32_to_cpu(arec->ar_startblock));
	}

	/*
	* Reverse map root block init
	*/
	static void
	xfs_rmaproot_init(
	struct xfs_mount *mp,
	struct xfs_buf *bp,
	struct aghdr_init_data *id)
	{
	struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
	struct xfs_rmap_rec *rrec;

	xfs_btree_init_block(mp, bp, XFS_BTNUM_RMAP, 0, 4, id->agno, 0);

	/*
	* mark the AG header regions as static metadata The BNO
	* btree block is the first block after the headers, so
	* it's location defines the size of region the static
	* metadata consumes.
	*
	* Note: unlike mkfs, we never have to account for log
	* space when growing the data regions
	*/
	rrec = XFS_RMAP_REC_ADDR(block, 1);
	rrec->rm_startblock = 0;
	rrec->rm_blockcount = cpu_to_be32(XFS_BNO_BLOCK(mp));
	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_FS);
	rrec->rm_offset = 0;

	/* account freespace btree root blocks */
	rrec = XFS_RMAP_REC_ADDR(block, 2);
	rrec->rm_startblock = cpu_to_be32(XFS_BNO_BLOCK(mp));
	rrec->rm_blockcount = cpu_to_be32(2);
	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
	rrec->rm_offset = 0;

	/* account inode btree root blocks */
	rrec = XFS_RMAP_REC_ADDR(block, 3);
	rrec->rm_startblock = cpu_to_be32(XFS_IBT_BLOCK(mp));
	rrec->rm_blockcount = cpu_to_be32(XFS_RMAP_BLOCK(mp) -
	XFS_IBT_BLOCK(mp));
	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_INOBT);
	rrec->rm_offset = 0;

	/* account for rmap btree root */
	rrec = XFS_RMAP_REC_ADDR(block, 4);
	rrec->rm_startblock = cpu_to_be32(XFS_RMAP_BLOCK(mp));
	rrec->rm_blockcount = cpu_to_be32(1);
	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
	rrec->rm_offset = 0;

	/* account for refc btree root */
	if (xfs_sb_version_hasreflink(&mp->m_sb)) {
	rrec = XFS_RMAP_REC_ADDR(block, 5);
	rrec->rm_startblock = cpu_to_be32(xfs_refc_block(mp));
	rrec->rm_blockcount = cpu_to_be32(1);
	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_REFC);
	rrec->rm_offset = 0;
	be16_add_cpu(&block->bb_numrecs, 1);
	}
	}

	/*
	* Initialise new secondary superblocks with the pre-grow geometry, but mark
	* them as "in progress" so we know they haven't yet been activated. This will
	* get cleared when the update with the new geometry information is done after
	* changes to the primary are committed. This isn't strictly necessary, but we
	* get it for free with the delayed buffer write lists and it means we can tell
	* if a grow operation didn't complete properly after the fact.
	*/
	static void
	xfs_sbblock_init(
	struct xfs_mount *mp,
	struct xfs_buf *bp,
	struct aghdr_init_data *id)
	{
	struct xfs_dsb *dsb = XFS_BUF_TO_SBP(bp);

	xfs_sb_to_disk(dsb, &mp->m_sb);
	dsb->sb_inprogress = 1;
	}

	static void
	xfs_agfblock_init(
	struct xfs_mount *mp,
	struct xfs_buf *bp,
	struct aghdr_init_data *id)
	{
	struct xfs_agf *agf = XFS_BUF_TO_AGF(bp);
	xfs_extlen_t tmpsize;

	agf->agf_magicnum = cpu_to_be32(XFS_AGF_MAGIC);
	agf->agf_versionnum = cpu_to_be32(XFS_AGF_VERSION);
	agf->agf_seqno = cpu_to_be32(id->agno);
	agf->agf_length = cpu_to_be32(id->agsize);
	agf->agf_roots[XFS_BTNUM_BNOi] = cpu_to_be32(XFS_BNO_BLOCK(mp));
	agf->agf_roots[XFS_BTNUM_CNTi] = cpu_to_be32(XFS_CNT_BLOCK(mp));
	agf->agf_levels[XFS_BTNUM_BNOi] = cpu_to_be32(1);
	agf->agf_levels[XFS_BTNUM_CNTi] = cpu_to_be32(1);
	if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
	agf->agf_roots[XFS_BTNUM_RMAPi] =
	cpu_to_be32(XFS_RMAP_BLOCK(mp));
	agf->agf_levels[XFS_BTNUM_RMAPi] = cpu_to_be32(1);
	agf->agf_rmap_blocks = cpu_to_be32(1);
	}

	agf->agf_flfirst = cpu_to_be32(1);
	agf->agf_fllast = 0;
	agf->agf_flcount = 0;
	tmpsize = id->agsize - mp->m_ag_prealloc_blocks;
	agf->agf_freeblks = cpu_to_be32(tmpsize);
	agf->agf_longest = cpu_to_be32(tmpsize);
	if (xfs_sb_version_hascrc(&mp->m_sb))
	uuid_copy(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid);
	if (xfs_sb_version_hasreflink(&mp->m_sb)) {
	agf->agf_refcount_root = cpu_to_be32(
	xfs_refc_block(mp));
	agf->agf_refcount_level = cpu_to_be32(1);
	agf->agf_refcount_blocks = cpu_to_be32(1);
	}
	}

	static void
	xfs_agflblock_init(
	struct xfs_mount *mp,
	struct xfs_buf *bp,
	struct aghdr_init_data *id)
	{
	struct xfs_agfl *agfl = XFS_BUF_TO_AGFL(bp);
	__be32 *agfl_bno;
	int bucket;

	if (xfs_sb_version_hascrc(&mp->m_sb)) {
	agfl->agfl_magicnum = cpu_to_be32(XFS_AGFL_MAGIC);
	agfl->agfl_seqno = cpu_to_be32(id->agno);
	uuid_copy(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid);
	}

	agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, bp);
	for (bucket = 0; bucket < xfs_agfl_size(mp); bucket++)
	agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK);
	}

	static void
	xfs_agiblock_init(
	struct xfs_mount *mp,
	struct xfs_buf *bp,
	struct aghdr_init_data *id)
	{
	struct xfs_agi *agi = XFS_BUF_TO_AGI(bp);
	int bucket;

	agi->agi_magicnum = cpu_to_be32(XFS_AGI_MAGIC);
	agi->agi_versionnum = cpu_to_be32(XFS_AGI_VERSION);
	agi->agi_seqno = cpu_to_be32(id->agno);
	agi->agi_length = cpu_to_be32(id->agsize);
	agi->agi_count = 0;
	agi->agi_root = cpu_to_be32(XFS_IBT_BLOCK(mp));
	agi->agi_level = cpu_to_be32(1);
	agi->agi_freecount = 0;
	agi->agi_newino = cpu_to_be32(NULLAGINO);
	agi->agi_dirino = cpu_to_be32(NULLAGINO);
	if (xfs_sb_version_hascrc(&mp->m_sb))
	uuid_copy(&agi->agi_uuid, &mp->m_sb.sb_meta_uuid);
	if (xfs_sb_version_hasfinobt(&mp->m_sb)) {
	agi->agi_free_root = cpu_to_be32(XFS_FIBT_BLOCK(mp));
	agi->agi_free_level = cpu_to_be32(1);
	}
	for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
	agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
	}

	typedef void (aghdr_init_work_f)(struct xfs_mount mp, struct xfs_buf *bp,
	struct aghdr_init_data *id);
	static int
	xfs_ag_init_hdr(
	struct xfs_mount *mp,
	struct aghdr_init_data *id,
	aghdr_init_work_f work,
	const struct xfs_buf_ops *ops)

	{
	struct xfs_buf *bp;

	bp = xfs_get_aghdr_buf(mp, id->daddr, id->numblks, 0, ops);
	if (!bp)
	return -ENOMEM;

	(*work)(mp, bp, id);

	xfs_buf_delwri_queue(bp, &id->buffer_list);
	xfs_buf_relse(bp);
	return 0;
	}

	struct xfs_aghdr_grow_data {
	xfs_daddr_t daddr;
	size_t numblks;
	const struct xfs_buf_ops *ops;
	aghdr_init_work_f work;
	xfs_btnum_t type;
	bool need_init;
	};

	/*
	* Prepare new AG headers to be written to disk. We use uncached buffers here,
	* as it is assumed these new AG headers are currently beyond the currently
	* valid filesystem address space. Using cached buffers would trip over EOFS
	* corruption detection alogrithms in the buffer cache lookup routines.
	*
	* This is a non-transactional function, but the prepared buffers are added to a
	* delayed write buffer list supplied by the caller so they can submit them to
	* disk and wait on them as required.
	*/
	int
	xfs_ag_init_headers(
	struct xfs_mount *mp,
	struct aghdr_init_data *id)

	{
	struct xfs_aghdr_grow_data aghdr_data[] = {
	{ /* SB */
	.daddr = XFS_AG_DADDR(mp, id->agno, XFS_SB_DADDR),
	.numblks = XFS_FSS_TO_BB(mp, 1),
	.ops = &xfs_sb_buf_ops,
	.work = &xfs_sbblock_init,
	.need_init = true
	},
	{ /* AGF */
	.daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGF_DADDR(mp)),
	.numblks = XFS_FSS_TO_BB(mp, 1),
	.ops = &xfs_agf_buf_ops,
	.work = &xfs_agfblock_init,
	.need_init = true
	},
	{ /* AGFL */
	.daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGFL_DADDR(mp)),
	.numblks = XFS_FSS_TO_BB(mp, 1),
	.ops = &xfs_agfl_buf_ops,
	.work = &xfs_agflblock_init,
	.need_init = true
	},
	{ /* AGI */
	.daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGI_DADDR(mp)),
	.numblks = XFS_FSS_TO_BB(mp, 1),
	.ops = &xfs_agi_buf_ops,
	.work = &xfs_agiblock_init,
	.need_init = true
	},
	{ /* BNO root block */
	.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_BNO_BLOCK(mp)),
	.numblks = BTOBB(mp->m_sb.sb_blocksize),
	.ops = &xfs_allocbt_buf_ops,
	.work = &xfs_bnoroot_init,
	.need_init = true
	},
	{ /* CNT root block */
	.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_CNT_BLOCK(mp)),
	.numblks = BTOBB(mp->m_sb.sb_blocksize),
	.ops = &xfs_allocbt_buf_ops,
	.work = &xfs_cntroot_init,
	.need_init = true
	},
	{ /* INO root block */
	.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_IBT_BLOCK(mp)),
	.numblks = BTOBB(mp->m_sb.sb_blocksize),
	.ops = &xfs_inobt_buf_ops,
	.work = &xfs_btroot_init,
	.type = XFS_BTNUM_INO,
	.need_init = true
	},
	{ /* FINO root block */
	.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_FIBT_BLOCK(mp)),
	.numblks = BTOBB(mp->m_sb.sb_blocksize),
	.ops = &xfs_inobt_buf_ops,
	.work = &xfs_btroot_init,
	.type = XFS_BTNUM_FINO,
	.need_init = xfs_sb_version_hasfinobt(&mp->m_sb)
	},
	{ /* RMAP root block */
	.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_RMAP_BLOCK(mp)),
	.numblks = BTOBB(mp->m_sb.sb_blocksize),
	.ops = &xfs_rmapbt_buf_ops,
	.work = &xfs_rmaproot_init,
	.need_init = xfs_sb_version_hasrmapbt(&mp->m_sb)
	},
	{ /* REFC root block */
	.daddr = XFS_AGB_TO_DADDR(mp, id->agno, xfs_refc_block(mp)),
	.numblks = BTOBB(mp->m_sb.sb_blocksize),
	.ops = &xfs_refcountbt_buf_ops,
	.work = &xfs_btroot_init,
	.type = XFS_BTNUM_REFC,
	.need_init = xfs_sb_version_hasreflink(&mp->m_sb)
	},
	{ /* NULL terminating block */
	.daddr = XFS_BUF_DADDR_NULL,
	}
	};
	struct xfs_aghdr_grow_data *dp;
	int error = 0;

	/* Account for AG free space in new AG */
	id->nfree += id->agsize - mp->m_ag_prealloc_blocks;
	for (dp = &aghdr_data[0]; dp->daddr != XFS_BUF_DADDR_NULL; dp++) {
	if (!dp->need_init)
	continue;

	id->daddr = dp->daddr;
	id->numblks = dp->numblks;
	id->type = dp->type;
	error = xfs_ag_init_hdr(mp, id, dp->work, dp->ops);
	if (error)
	break;
	}
	return error;
	}

	/*
	* Extent the AG indicated by the @id by the length passed in
	*/
	int
	xfs_ag_extend_space(
	struct xfs_mount *mp,
	struct xfs_trans *tp,
	struct aghdr_init_data *id,
	xfs_extlen_t len)
	{
	struct xfs_owner_info oinfo;
	struct xfs_buf *bp;
	struct xfs_agi *agi;
	struct xfs_agf *agf;
	int error;

	/*
	* Change the agi length.
	*/
	error = xfs_ialloc_read_agi(mp, tp, id->agno, &bp);
	if (error)
	return error;

	agi = XFS_BUF_TO_AGI(bp);
	be32_add_cpu(&agi->agi_length, len);
	ASSERT(id->agno == mp->m_sb.sb_agcount - 1 \|\|
	be32_to_cpu(agi->agi_length) == mp->m_sb.sb_agblocks);
	xfs_ialloc_log_agi(tp, bp, XFS_AGI_LENGTH);

	/*
	* Change agf length.
	*/
	error = xfs_alloc_read_agf(mp, tp, id->agno, 0, &bp);
	if (error)
	return error;

	agf = XFS_BUF_TO_AGF(bp);
	be32_add_cpu(&agf->agf_length, len);
	ASSERT(agf->agf_length == agi->agi_length);
	xfs_alloc_log_agf(tp, bp, XFS_AGF_LENGTH);

	/*
	* Free the new space.
	*
	* XFS_RMAP_OWN_NULL is used here to tell the rmap btree that
	* this doesn't actually exist in the rmap btree.
	*/
	xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_NULL);
	error = xfs_rmap_free(tp, bp, id->agno,
	be32_to_cpu(agf->agf_length) - len,
	len, &oinfo);
	if (error)
	return error;

	return xfs_free_extent(tp, XFS_AGB_TO_FSB(mp, id->agno,
	be32_to_cpu(agf->agf_length) - len),
	len, &oinfo, XFS_AG_RESV_NONE);
	}