summaryrefslogtreecommitdiff
path: root/fs/ocfs2/extent_map.c
blob: 937c2722b75347465ed5ff78fb3b7a069e7f849e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
/* -*- 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;
}

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;
}