suballoc.c

linux 内核源代码

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * suballoc.c
 *
 * metadata alloc and free
 * Inspired by ext3 block groups.
 *
 * Copyright (C) 2002, 2004 Oracle.  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; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will 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 to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>

#define MLOG_MASK_PREFIX ML_DISK_ALLOC
#include <cluster/masklog.h>

#include "ocfs2.h"

#include "alloc.h"
#include "dlmglue.h"
#include "inode.h"
#include "journal.h"
#include "localalloc.h"
#include "suballoc.h"
#include "super.h"
#include "sysfile.h"
#include "uptodate.h"

#include "buffer_head_io.h"

static inline void ocfs2_debug_bg(struct ocfs2_group_desc *bg);
static inline void ocfs2_debug_suballoc_inode(struct ocfs2_dinode *fe);
static inline u16 ocfs2_find_victim_chain(struct ocfs2_chain_list *cl);
static int ocfs2_block_group_fill(handle_t *handle,
				  struct inode *alloc_inode,
				  struct buffer_head *bg_bh,
				  u64 group_blkno,
				  u16 my_chain,
				  struct ocfs2_chain_list *cl);
static int ocfs2_block_group_alloc(struct ocfs2_super *osb,
				   struct inode *alloc_inode,
				   struct buffer_head *bh);

static int ocfs2_cluster_group_search(struct inode *inode,
				      struct buffer_head *group_bh,
				      u32 bits_wanted, u32 min_bits,
				      u16 *bit_off, u16 *bits_found);
static int ocfs2_block_group_search(struct inode *inode,
				    struct buffer_head *group_bh,
				    u32 bits_wanted, u32 min_bits,
				    u16 *bit_off, u16 *bits_found);
static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb,
				     struct ocfs2_alloc_context *ac,
				     handle_t *handle,
				     u32 bits_wanted,
				     u32 min_bits,
				     u16 *bit_off,
				     unsigned int *num_bits,
				     u64 *bg_blkno);
static int ocfs2_test_bg_bit_allocatable(struct buffer_head *bg_bh,
					 int nr);
static inline int ocfs2_block_group_set_bits(handle_t *handle,
					     struct inode *alloc_inode,
					     struct ocfs2_group_desc *bg,
					     struct buffer_head *group_bh,
					     unsigned int bit_off,
					     unsigned int num_bits);
static inline int ocfs2_block_group_clear_bits(handle_t *handle,
					       struct inode *alloc_inode,
					       struct ocfs2_group_desc *bg,
					       struct buffer_head *group_bh,
					       unsigned int bit_off,
					       unsigned int num_bits);

static int ocfs2_relink_block_group(handle_t *handle,
				    struct inode *alloc_inode,
				    struct buffer_head *fe_bh,
				    struct buffer_head *bg_bh,
				    struct buffer_head *prev_bg_bh,
				    u16 chain);
static inline int ocfs2_block_group_reasonably_empty(struct ocfs2_group_desc *bg,
						     u32 wanted);
static inline u32 ocfs2_desc_bitmap_to_cluster_off(struct inode *inode,
						   u64 bg_blkno,
						   u16 bg_bit_off);
static inline u64 ocfs2_which_cluster_group(struct inode *inode,
					    u32 cluster);
static inline void ocfs2_block_to_cluster_group(struct inode *inode,
						u64 data_blkno,
						u64 *bg_blkno,
						u16 *bg_bit_off);

void ocfs2_free_alloc_context(struct ocfs2_alloc_context *ac)
{
	struct inode *inode = ac->ac_inode;

	if (inode) {
		if (ac->ac_which != OCFS2_AC_USE_LOCAL)
			ocfs2_meta_unlock(inode, 1);

		mutex_unlock(&inode->i_mutex);

		iput(inode);
	}
	if (ac->ac_bh)
		brelse(ac->ac_bh);
	kfree(ac);
}

static u32 ocfs2_bits_per_group(struct ocfs2_chain_list *cl)
{
	return (u32)le16_to_cpu(cl->cl_cpg) * (u32)le16_to_cpu(cl->cl_bpc);
}

/* somewhat more expensive than our other checks, so use sparingly. */
static int ocfs2_check_group_descriptor(struct super_block *sb,
					struct ocfs2_dinode *di,
					struct ocfs2_group_desc *gd)
{
	unsigned int max_bits;

	if (!OCFS2_IS_VALID_GROUP_DESC(gd)) {
		OCFS2_RO_ON_INVALID_GROUP_DESC(sb, gd);
		return -EIO;
	}

	if (di->i_blkno != gd->bg_parent_dinode) {
		ocfs2_error(sb, "Group descriptor # %llu has bad parent "
			    "pointer (%llu, expected %llu)",
			    (unsigned long long)le64_to_cpu(gd->bg_blkno),
			    (unsigned long long)le64_to_cpu(gd->bg_parent_dinode),
			    (unsigned long long)le64_to_cpu(di->i_blkno));
		return -EIO;
	}

	max_bits = le16_to_cpu(di->id2.i_chain.cl_cpg) * le16_to_cpu(di->id2.i_chain.cl_bpc);
	if (le16_to_cpu(gd->bg_bits) > max_bits) {
		ocfs2_error(sb, "Group descriptor # %llu has bit count of %u",
			    (unsigned long long)le64_to_cpu(gd->bg_blkno),
			    le16_to_cpu(gd->bg_bits));
		return -EIO;
	}

	if (le16_to_cpu(gd->bg_chain) >=
	    le16_to_cpu(di->id2.i_chain.cl_next_free_rec)) {
		ocfs2_error(sb, "Group descriptor # %llu has bad chain %u",
			    (unsigned long long)le64_to_cpu(gd->bg_blkno),
			    le16_to_cpu(gd->bg_chain));
		return -EIO;
	}

	if (le16_to_cpu(gd->bg_free_bits_count) > le16_to_cpu(gd->bg_bits)) {
		ocfs2_error(sb, "Group descriptor # %llu has bit count %u but "
			    "claims that %u are free",
			    (unsigned long long)le64_to_cpu(gd->bg_blkno),
			    le16_to_cpu(gd->bg_bits),
			    le16_to_cpu(gd->bg_free_bits_count));
		return -EIO;
	}

	if (le16_to_cpu(gd->bg_bits) > (8 * le16_to_cpu(gd->bg_size))) {
		ocfs2_error(sb, "Group descriptor # %llu has bit count %u but "
			    "max bitmap bits of %u",
			    (unsigned long long)le64_to_cpu(gd->bg_blkno),
			    le16_to_cpu(gd->bg_bits),
			    8 * le16_to_cpu(gd->bg_size));
		return -EIO;
	}

	return 0;
}

static int ocfs2_block_group_fill(handle_t *handle,
				  struct inode *alloc_inode,
				  struct buffer_head *bg_bh,
				  u64 group_blkno,
				  u16 my_chain,
				  struct ocfs2_chain_list *cl)
{
	int status = 0;
	struct ocfs2_group_desc *bg = (struct ocfs2_group_desc *) bg_bh->b_data;
	struct super_block * sb = alloc_inode->i_sb;

	mlog_entry_void();

	if (((unsigned long long) bg_bh->b_blocknr) != group_blkno) {
		ocfs2_error(alloc_inode->i_sb, "group block (%llu) != "
			    "b_blocknr (%llu)",
			    (unsigned long long)group_blkno,
			    (unsigned long long) bg_bh->b_blocknr);
		status = -EIO;
		goto bail;
	}

	status = ocfs2_journal_access(handle,
				      alloc_inode,
				      bg_bh,
				      OCFS2_JOURNAL_ACCESS_CREATE);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	memset(bg, 0, sb->s_blocksize);
	strcpy(bg->bg_signature, OCFS2_GROUP_DESC_SIGNATURE);
	bg->bg_generation = cpu_to_le32(OCFS2_SB(sb)->fs_generation);
	bg->bg_size = cpu_to_le16(ocfs2_group_bitmap_size(sb));
	bg->bg_bits = cpu_to_le16(ocfs2_bits_per_group(cl));
	bg->bg_chain = cpu_to_le16(my_chain);
	bg->bg_next_group = cl->cl_recs[my_chain].c_blkno;
	bg->bg_parent_dinode = cpu_to_le64(OCFS2_I(alloc_inode)->ip_blkno);
	bg->bg_blkno = cpu_to_le64(group_blkno);
	/* set the 1st bit in the bitmap to account for the descriptor block */
	ocfs2_set_bit(0, (unsigned long *)bg->bg_bitmap);
	bg->bg_free_bits_count = cpu_to_le16(le16_to_cpu(bg->bg_bits) - 1);

	status = ocfs2_journal_dirty(handle, bg_bh);
	if (status < 0)
		mlog_errno(status);

	/* There is no need to zero out or otherwise initialize the
	 * other blocks in a group - All valid FS metadata in a block
	 * group stores the superblock fs_generation value at
	 * allocation time. */

bail:
	mlog_exit(status);
	return status;
}

static inline u16 ocfs2_find_smallest_chain(struct ocfs2_chain_list *cl)
{
	u16 curr, best;

	best = curr = 0;
	while (curr < le16_to_cpu(cl->cl_count)) {
		if (le32_to_cpu(cl->cl_recs[best].c_total) >
		    le32_to_cpu(cl->cl_recs[curr].c_total))
			best = curr;
		curr++;
	}
	return best;
}

/*
 * We expect the block group allocator to already be locked.
 */
static int ocfs2_block_group_alloc(struct ocfs2_super *osb,
				   struct inode *alloc_inode,
				   struct buffer_head *bh)
{
	int status, credits;
	struct ocfs2_dinode *fe = (struct ocfs2_dinode *) bh->b_data;
	struct ocfs2_chain_list *cl;
	struct ocfs2_alloc_context *ac = NULL;
	handle_t *handle = NULL;
	u32 bit_off, num_bits;
	u16 alloc_rec;
	u64 bg_blkno;
	struct buffer_head *bg_bh = NULL;
	struct ocfs2_group_desc *bg;

	BUG_ON(ocfs2_is_cluster_bitmap(alloc_inode));

	mlog_entry_void();

	cl = &fe->id2.i_chain;
	status = ocfs2_reserve_clusters(osb,
					le16_to_cpu(cl->cl_cpg),
					&ac);
	if (status < 0) {
		if (status != -ENOSPC)
			mlog_errno(status);
		goto bail;
	}

	credits = ocfs2_calc_group_alloc_credits(osb->sb,
						 le16_to_cpu(cl->cl_cpg));
	handle = ocfs2_start_trans(osb, credits);
	if (IS_ERR(handle)) {
		status = PTR_ERR(handle);
		handle = NULL;
		mlog_errno(status);
		goto bail;
	}

	status = ocfs2_claim_clusters(osb,
				      handle,
				      ac,
				      le16_to_cpu(cl->cl_cpg),
				      &bit_off,
				      &num_bits);
	if (status < 0) {
		if (status != -ENOSPC)
			mlog_errno(status);
		goto bail;
	}

	alloc_rec = ocfs2_find_smallest_chain(cl);

	/* setup the group */
	bg_blkno = ocfs2_clusters_to_blocks(osb->sb, bit_off);
	mlog(0, "new descriptor, record %u, at block %llu\n",
	     alloc_rec, (unsigned long long)bg_blkno);

	bg_bh = sb_getblk(osb->sb, bg_blkno);
	if (!bg_bh) {
		status = -EIO;
		mlog_errno(status);
		goto bail;
	}
	ocfs2_set_new_buffer_uptodate(alloc_inode, bg_bh);

	status = ocfs2_block_group_fill(handle,
					alloc_inode,
					bg_bh,
					bg_blkno,
					alloc_rec,
					cl);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	bg = (struct ocfs2_group_desc *) bg_bh->b_data;

	status = ocfs2_journal_access(handle, alloc_inode,
				      bh, OCFS2_JOURNAL_ACCESS_WRITE);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	le32_add_cpu(&cl->cl_recs[alloc_rec].c_free,
		     le16_to_cpu(bg->bg_free_bits_count));
	le32_add_cpu(&cl->cl_recs[alloc_rec].c_total, le16_to_cpu(bg->bg_bits));
	cl->cl_recs[alloc_rec].c_blkno  = cpu_to_le64(bg_blkno);
	if (le16_to_cpu(cl->cl_next_free_rec) < le16_to_cpu(cl->cl_count))
		le16_add_cpu(&cl->cl_next_free_rec, 1);

	le32_add_cpu(&fe->id1.bitmap1.i_used, le16_to_cpu(bg->bg_bits) -
					le16_to_cpu(bg->bg_free_bits_count));
	le32_add_cpu(&fe->id1.bitmap1.i_total, le16_to_cpu(bg->bg_bits));
	le32_add_cpu(&fe->i_clusters, le16_to_cpu(cl->cl_cpg));

	status = ocfs2_journal_dirty(handle, bh);
	if (status < 0) {
		mlog_errno(status);
		goto bail;
	}

	spin_lock(&OCFS2_I(alloc_inode)->ip_lock);
	OCFS2_I(alloc_inode)->ip_clusters = le32_to_cpu(fe->i_clusters);
	fe->i_size = cpu_to_le64(ocfs2_clusters_to_bytes(alloc_inode->i_sb,
					     le32_to_cpu(fe->i_clusters)));
	spin_unlock(&OCFS2_I(alloc_inode)->ip_lock);
	i_size_write(alloc_inode, le64_to_cpu(fe->i_size));
	alloc_inode->i_blocks = ocfs2_inode_sector_count(alloc_inode);

	status = 0;
bail:
	if (handle)
		ocfs2_commit_trans(osb, handle);

	if (ac)
		ocfs2_free_alloc_context(ac);

	if (bg_bh)
		brelse(bg_bh);

	mlog_exit(status);
	return status;
}

static int ocfs2_reserve_suballoc_bits(struct ocfs2_super *osb,
				       struct ocfs2_alloc_context *ac,
				       int type,
				       u32 slot)
{
	int status;
	u32 bits_wanted = ac->ac_bits_wanted;
	struct inode *alloc_inode;
	struct buffer_head *bh = NULL;
	struct ocfs2_dinode *fe;
	u32 free_bits;

	mlog_entry_void();

	alloc_inode = ocfs2_get_system_file_inode(osb, type, slot);
	if (!alloc_inode) {
		mlog_errno(-EINVAL);
		return -EINVAL;
	}

	mutex_lock(&alloc_inode->i_mutex);

	status = ocfs2_meta_lock(alloc_inode, &bh, 1);
	if (status < 0) {
		mutex_unlock(&alloc_inode->i_mutex);
		iput(alloc_inode);

		mlog_errno(status);
		return status;
	}

	ac->ac_inode = alloc_inode;

	fe = (struct ocfs2_dinode *) bh->b_data;
	if (!OCFS2_IS_VALID_DINODE(fe)) {
		OCFS2_RO_ON_INVALID_DINODE(alloc_inode->i_sb, fe);
		status = -EIO;
		goto bail;
	}
	if (!(fe->i_flags & cpu_to_le32(OCFS2_CHAIN_FL))) {
		ocfs2_error(alloc_inode->i_sb, "Invalid chain allocator %llu",
			    (unsigned long long)le64_to_cpu(fe->i_blkno));
		status = -EIO;
		goto bail;
	}

	free_bits = le32_to_cpu(fe->id1.bitmap1.i_total) -
		le32_to_cpu(fe->id1.bitmap1.i_used);

	if (bits_wanted > free_bits) {
		/* cluster bitmap never grows */
		if (ocfs2_is_cluster_bitmap(alloc_inode)) {
			mlog(0, "Disk Full: wanted=%u, free_bits=%u\n",
			     bits_wanted, free_bits);
			status = -ENOSPC;
			goto bail;
		}

		status = ocfs2_block_group_alloc(osb, alloc_inode, bh);
		if (status < 0) {