1. 根目录:
2. fs
3. xfs
4. xfs_alloc_btree.c

/*
 * Copyright (c) 2000-2001,2005 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_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_btree_trace.h"
#include "xfs_alloc.h"
#include "xfs_error.h"
#include "xfs_trace.h"


STATIC struct xfs_btree_cur *
xfs_allocbt_dup_cursor(
	struct xfs_btree_cur	*cur)
{
	return xfs_allocbt_init_cursor(cur->bc_mp, cur->bc_tp,
			cur->bc_private.a.agbp, cur->bc_private.a.agno,
			cur->bc_btnum);
}

STATIC void
xfs_allocbt_set_root(
	struct xfs_btree_cur	*cur,
	union xfs_btree_ptr	*ptr,
	int			inc)
{
	struct xfs_buf		*agbp = cur->bc_private.a.agbp;
	struct xfs_agf		*agf = XFS_BUF_TO_AGF(agbp);
	xfs_agnumber_t		seqno = be32_to_cpu(agf->agf_seqno);
	int			btnum = cur->bc_btnum;
	struct xfs_perag	*pag = xfs_perag_get(cur->bc_mp, seqno);

	ASSERT(ptr->s != 0);

	agf->agf_roots[btnum] = ptr->s;
	be32_add_cpu(&agf->agf_levels[btnum], inc);
	pag->pagf_levels[btnum] += inc;
	xfs_perag_put(pag);

	xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
}

STATIC int
xfs_allocbt_alloc_block(
	struct xfs_btree_cur	*cur,
	union xfs_btree_ptr	*start,
	union xfs_btree_ptr	*new,
	int			length,
	int			*stat)
{
	int			error;
	xfs_agblock_t		bno;

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);

	/* Allocate the new block from the freelist. If we can't, give up.  */
	error = xfs_alloc_get_freelist(cur->bc_tp, cur->bc_private.a.agbp,
				       &bno, 1);
	if (error) {
		XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
		return error;
	}

	if (bno == NULLAGBLOCK) {
		XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
		*stat = 0;
		return 0;
	}

	xfs_trans_agbtree_delta(cur->bc_tp, 1);
	new->s = cpu_to_be32(bno);

	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = 1;
	return 0;
}

STATIC int
xfs_allocbt_free_block(
	struct xfs_btree_cur	*cur,
	struct xfs_buf		*bp)
{
	struct xfs_buf		*agbp = cur->bc_private.a.agbp;
	struct xfs_agf		*agf = XFS_BUF_TO_AGF(agbp);
	xfs_agblock_t		bno;
	int			error;

	bno = xfs_daddr_to_agbno(cur->bc_mp, XFS_BUF_ADDR(bp));
	error = xfs_alloc_put_freelist(cur->bc_tp, agbp, NULL, bno, 1);
	if (error)
		return error;

	/*
	 * Since blocks move to the free list without the coordination used in
	 * xfs_bmap_finish, we can't allow block to be available for
	 * reallocation and non-transaction writing (user data) until we know
	 * that the transaction that moved it to the free list is permanently
	 * on disk. We track the blocks by declaring these blocks as "busy";
	 * the busy list is maintained on a per-ag basis and each transaction
	 * records which entries should be removed when the iclog commits to
	 * disk. If a busy block is allocated, the iclog is pushed up to the
	 * LSN that freed the block.
	 */
	xfs_alloc_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1);
	xfs_trans_agbtree_delta(cur->bc_tp, -1);
	return 0;
}

/*
 * Update the longest extent in the AGF
 */
STATIC void
xfs_allocbt_update_lastrec(
	struct xfs_btree_cur	*cur,
	struct xfs_btree_block	*block,
	union xfs_btree_rec	*rec,
	int			ptr,
	int			reason)
{
	struct xfs_agf		*agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
	xfs_agnumber_t		seqno = be32_to_cpu(agf->agf_seqno);
	struct xfs_perag	*pag;
	__be32			len;
	int			numrecs;

	ASSERT(cur->bc_btnum == XFS_BTNUM_CNT);

	switch (reason) {
	case LASTREC_UPDATE:
		/*
		 * If this is the last leaf block and it's the last record,
		 * then update the size of the longest extent in the AG.
		 */
		if (ptr != xfs_btree_get_numrecs(block))
			return;
		len = rec->alloc.ar_blockcount;
		break;
	case LASTREC_INSREC:
		if (be32_to_cpu(rec->alloc.ar_blockcount) <=
		    be32_to_cpu(agf->agf_longest))
			return;
		len = rec->alloc.ar_blockcount;
		break;
	case LASTREC_DELREC:
		numrecs = xfs_btree_get_numrecs(block);
		if (ptr <= numrecs)
			return;
		ASSERT(ptr == numrecs + 1);

		if (numrecs) {
			xfs_alloc_rec_t *rrp;

			rrp = XFS_ALLOC_REC_ADDR(cur->bc_mp, block, numrecs);
			len = rrp->ar_blockcount;
		} else {
			len = 0;
		}

		break;
	default:
		ASSERT(0);
		return;
	}

	agf->agf_longest = len;
	pag = xfs_perag_get(cur->bc_mp, seqno);
	pag->pagf_longest = be32_to_cpu(len);
	xfs_perag_put(pag);
	xfs_alloc_log_agf(cur->bc_tp, cur->bc_private.a.agbp, XFS_AGF_LONGEST);
}

STATIC int
xfs_allocbt_get_minrecs(
	struct xfs_btree_cur	*cur,
	int			level)
{
	return cur->bc_mp->m_alloc_mnr[level != 0];
}

STATIC int
xfs_allocbt_get_maxrecs(
	struct xfs_btree_cur	*cur,
	int			level)
{
	return cur->bc_mp->m_alloc_mxr[level != 0];
}

STATIC void
xfs_allocbt_init_key_from_rec(
	union xfs_btree_key	*key,
	union xfs_btree_rec	*rec)
{
	ASSERT(rec->alloc.ar_startblock != 0);

	key->alloc.ar_startblock = rec->alloc.ar_startblock;
	key->alloc.ar_blockcount = rec->alloc.ar_blockcount;
}

STATIC void
xfs_allocbt_init_rec_from_key(
	union xfs_btree_key	*key,
	union xfs_btree_rec	*rec)
{
	ASSERT(key->alloc.ar_startblock != 0);

	rec->alloc.ar_startblock = key->alloc.ar_startblock;
	rec->alloc.ar_blockcount = key->alloc.ar_blockcount;
}

STATIC void
xfs_allocbt_init_rec_from_cur(
	struct xfs_btree_cur	*cur,
	union xfs_btree_rec	*rec)
{
	ASSERT(cur->bc_rec.a.ar_startblock != 0);

	rec->alloc.ar_startblock = cpu_to_be32(cur->bc_rec.a.ar_startblock);
	rec->alloc.ar_blockcount = cpu_to_be32(cur->bc_rec.a.ar_blockcount);
}

STATIC void
xfs_allocbt_init_ptr_from_cur(
	struct xfs_btree_cur	*cur,
	union xfs_btree_ptr	*ptr)
{
	struct xfs_agf		*agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);

	ASSERT(cur->bc_private.a.agno == be32_to_cpu(agf->agf_seqno));
	ASSERT(agf->agf_roots[cur->bc_btnum] != 0);

	ptr->s = agf->agf_roots[cur->bc_btnum];
}

STATIC __int64_t
xfs_allocbt_key_diff(
	struct xfs_btree_cur	*cur,
	union xfs_btree_key	*key)
{
	xfs_alloc_rec_incore_t	*rec = &cur->bc_rec.a;
	xfs_alloc_key_t		*kp = &key->alloc;
	__int64_t		diff;

	if (cur->bc_btnum == XFS_BTNUM_BNO) {
		return (__int64_t)be32_to_cpu(kp->ar_startblock) -
				rec->ar_startblock;
	}

	diff = (__int64_t)be32_to_cpu(kp->ar_blockcount) - rec->ar_blockcount;
	if (diff)
		return diff;

	return (__int64_t)be32_to_cpu(kp->ar_startblock) - rec->ar_startblock;
}

#ifdef DEBUG
STATIC int
xfs_allocbt_keys_inorder(
	struct xfs_btree_cur	*cur,
	union xfs_btree_key	*k1,
	union xfs_btree_key	*k2)
{
	if (cur->bc_btnum == XFS_BTNUM_BNO) {
		return be32_to_cpu(k1->alloc.ar_startblock) <
		       be32_to_cpu(k2->alloc.ar_startblock);
	} else {
		return be32_to_cpu(k1->alloc.ar_blockcount) <
			be32_to_cpu(k2->alloc.ar_blockcount) ||
			(k1->alloc.ar_blockcount == k2->alloc.ar_blockcount &&
			 be32_to_cpu(k1->alloc.ar_startblock) <
			 be32_to_cpu(k2->alloc.ar_startblock));
	}
}

STATIC int
xfs_allocbt_recs_inorder(
	struct xfs_btree_cur	*cur,
	union xfs_btree_rec	*r1,
	union xfs_btree_rec	*r2)
{
	if (cur->bc_btnum == XFS_BTNUM_BNO) {
		return be32_to_cpu(r1->alloc.ar_startblock) +
			be32_to_cpu(r1->alloc.ar_blockcount) <=
			be32_to_cpu(r2->alloc.ar_startblock);
	} else {
		return be32_to_cpu(r1->alloc.ar_blockcount) <
			be32_to_cpu(r2->alloc.ar_blockcount) ||
			(r1->alloc.ar_blockcount == r2->alloc.ar_blockcount &&
			 be32_to_cpu(r1->alloc.ar_startblock) <
			 be32_to_cpu(r2->alloc.ar_startblock));
	}
}
#endif	/* DEBUG */

#ifdef XFS_BTREE_TRACE
ktrace_t	*xfs_allocbt_trace_buf;

STATIC void
xfs_allocbt_trace_enter(
	struct xfs_btree_cur	*cur,
	const char		*func,
	char			*s,
	int			type,
	int			line,
	__psunsigned_t		a0,
	__psunsigned_t		a1,
	__psunsigned_t		a2,
	__psunsigned_t		a3,
	__psunsigned_t		a4,
	__psunsigned_t		a5,
	__psunsigned_t		a6,
	__psunsigned_t		a7,
	__psunsigned_t		a8,
	__psunsigned_t		a9,
	__psunsigned_t		a10)
{
	ktrace_enter(xfs_allocbt_trace_buf, (void *)(__psint_t)type,
		(void *)func, (void *)s, NULL, (void *)cur,
		(void *)a0, (void *)a1, (void *)a2, (void *)a3,
		(void *)a4, (void *)a5, (void *)a6, (void *)a7,
		(void *)a8, (void *)a9, (void *)a10);
}

STATIC void
xfs_allocbt_trace_cursor(
	struct xfs_btree_cur	*cur,
	__uint32_t		*s0,
	__uint64_t		*l0,
	__uint64_t		*l1)
{
	*s0 = cur->bc_private.a.agno;
	*l0 = cur->bc_rec.a.ar_startblock;
	*l1 = cur->bc_rec.a.ar_blockcount;
}

STATIC void
xfs_allocbt_trace_key(
	struct xfs_btree_cur	*cur,
	union xfs_btree_key	*key,
	__uint64_t		*l0,
	__uint64_t		*l1)
{
	*l0 = be32_to_cpu(key->alloc.ar_startblock);
	*l1 = be32_to_cpu(key->alloc.ar_blockcount);
}

STATIC void
xfs_allocbt_trace_record(
	struct xfs_btree_cur	*cur,
	union xfs_btree_rec	*rec,
	__uint64_t		*l0,
	__uint64_t		*l1,
	__uint64_t		*l2)
{
	*l0 = be32_to_cpu(rec->alloc.ar_startblock);
	*l1 = be32_to_cpu(rec->alloc.ar_blockcount);
	*l2 = 0;
}
#endif /* XFS_BTREE_TRACE */

static const struct xfs_btree_ops xfs_allocbt_ops = {
	.rec_len		= sizeof(xfs_alloc_rec_t),
	.key_len		= sizeof(xfs_alloc_key_t),

	.dup_cursor		= xfs_allocbt_dup_cursor,
	.set_root		= xfs_allocbt_set_root,
	.alloc_block		= xfs_allocbt_alloc_block,
	.free_block		= xfs_allocbt_free_block,
	.update_lastrec		= xfs_allocbt_update_lastrec,
	.get_minrecs		= xfs_allocbt_get_minrecs,
	.get_maxrecs		= xfs_allocbt_get_maxrecs,
	.init_key_from_rec	= xfs_allocbt_init_key_from_rec,
	.init_rec_from_key	= xfs_allocbt_init_rec_from_key,
	.init_rec_from_cur	= xfs_allocbt_init_rec_from_cur,
	.init_ptr_from_cur	= xfs_allocbt_init_ptr_from_cur,
	.key_diff		= xfs_allocbt_key_diff,

#ifdef DEBUG
	.keys_inorder		= xfs_allocbt_keys_inorder,
	.recs_inorder		= xfs_allocbt_recs_inorder,
#endif

#ifdef XFS_BTREE_TRACE
	.trace_enter		= xfs_allocbt_trace_enter,
	.trace_cursor		= xfs_allocbt_trace_cursor,
	.trace_key		= xfs_allocbt_trace_key,
	.trace_record		= xfs_allocbt_trace_record,
#endif
};

/*
 * Allocate a new allocation btree cursor.
 */
struct xfs_btree_cur *			/* new alloc btree cursor */
xfs_allocbt_init_cursor(
	struct xfs_mount	*mp,		/* file system mount point */
	struct xfs_trans	*tp,		/* transaction pointer */
	struct xfs_buf		*agbp,		/* buffer for agf structure */
	xfs_agnumber_t		agno,		/* allocation group number */
	xfs_btnum_t		btnum)		/* btree identifier */
{
	struct xfs_agf		*agf = XFS_BUF_TO_AGF(agbp);
	struct xfs_btree_cur	*cur;

	ASSERT(btnum == XFS_BTNUM_BNO || btnum == XFS_BTNUM_CNT);

	cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_SLEEP);

	cur->bc_tp = tp;
	cur->bc_mp = mp;
	cur->bc_nlevels = be32_to_cpu(agf->agf_levels[btnum]);
	cur->bc_btnum = btnum;
	cur->bc_blocklog = mp->m_sb.sb_blocklog;

	cur->bc_ops = &xfs_allocbt_ops;
	if (btnum == XFS_BTNUM_CNT)
		cur->bc_flags = XFS_BTREE_LASTREC_UPDATE;

	cur->bc_private.a.agbp = agbp;
	cur->bc_private.a.agno = agno;

	return cur;
}

/*
 * Calculate number of records in an alloc btree block.
 */
int
xfs_allocbt_maxrecs(
	struct xfs_mount	*mp,
	int			blocklen,
	int			leaf)
{
	blocklen -= XFS_ALLOC_BLOCK_LEN(mp);

	if (leaf)
		return blocklen / sizeof(xfs_alloc_rec_t);
	return blocklen / (sizeof(xfs_alloc_key_t) + sizeof(xfs_alloc_ptr_t));
}