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/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* extent_map.c
*
* Block/Cluster mapping functions
*
* Copyright (C) 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, version 2, as published by the Free Software Foundation.
*
* 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/init.h>
#include <linux/types.h>
#define MLOG_MASK_PREFIX ML_EXTENT_MAP
#include <cluster/masklog.h>
#include "ocfs2.h"
#include "alloc.h"
#include "extent_map.h"
#include "inode.h"
#include "super.h"
#include "buffer_head_io.h"
/*
* Return the index of the extent record which contains cluster #v_cluster.
* -1 is returned if it was not found.
*
* Should work fine on interior and exterior nodes.
*/
static int ocfs2_search_extent_list(struct ocfs2_extent_list *el,
u32 v_cluster)
{
int ret = -1;
int i;
struct ocfs2_extent_rec *rec;
u32 rec_end, rec_start;
for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
rec = &el->l_recs[i];
rec_start = le32_to_cpu(rec->e_cpos);
rec_end = rec_start + le32_to_cpu(rec->e_clusters);
if (v_cluster >= rec_start && v_cluster < rec_end) {
ret = i;
break;
}
}
return ret;
}
static int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
u32 *p_cluster, u32 *num_clusters)
{
int ret, i;
struct buffer_head *di_bh = NULL;
struct buffer_head *eb_bh = NULL;
struct ocfs2_dinode *di;
struct ocfs2_extent_block *eb;
struct ocfs2_extent_list *el;
struct ocfs2_extent_rec *rec;
u32 coff;
ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), OCFS2_I(inode)->ip_blkno,
&di_bh, OCFS2_BH_CACHED, inode);
if (ret) {
mlog_errno(ret);
goto out;
}
di = (struct ocfs2_dinode *) di_bh->b_data;
el = &di->id2.i_list;
if (el->l_tree_depth) {
ret = ocfs2_find_leaf(inode, el, v_cluster, &eb_bh);
if (ret) {
mlog_errno(ret);
goto out;
}
eb = (struct ocfs2_extent_block *) eb_bh->b_data;
el = &eb->h_list;
}
i = ocfs2_search_extent_list(el, v_cluster);
if (i == -1) {
/*
* A hole was found. Return some canned values that
* callers can key on.
*/
*p_cluster = 0;
if (num_clusters)
*num_clusters = 1;
} else {
rec = &el->l_recs[i];
BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
if (!rec->e_blkno) {
ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
"record (%u, %u, 0)", inode->i_ino,
le32_to_cpu(rec->e_cpos),
le32_to_cpu(rec->e_clusters));
ret = -EROFS;
goto out;
}
coff = v_cluster - le32_to_cpu(rec->e_cpos);
*p_cluster = ocfs2_blocks_to_clusters(inode->i_sb,
le64_to_cpu(rec->e_blkno));
*p_cluster = *p_cluster + coff;
if (num_clusters)
*num_clusters = le32_to_cpu(rec->e_clusters) - coff;
}
out:
brelse(di_bh);
brelse(eb_bh);
return ret;
}
/*
* This expects alloc_sem to be held. The allocation cannot change at
* all while the map is in the process of being updated.
*/
int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
int *ret_count)
{
int ret;
int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
u32 cpos, num_clusters, p_cluster;
u64 boff = 0;
cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
ret = ocfs2_get_clusters(inode, cpos, &p_cluster, &num_clusters);
if (ret) {
mlog_errno(ret);
goto out;
}
/*
* p_cluster == 0 indicates a hole.
*/
if (p_cluster) {
boff = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);
boff += (v_blkno & (u64)(bpc - 1));
}
*p_blkno = boff;
if (ret_count) {
*ret_count = ocfs2_clusters_to_blocks(inode->i_sb, num_clusters);
*ret_count -= v_blkno & (u64)(bpc - 1);
}
out:
return ret;
}
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