1 /* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
6 * Block/Cluster mapping functions
8 * Copyright (C) 2004 Oracle. All rights reserved.
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public
12 * License, version 2, as published by the Free Software Foundation.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
19 * You should have received a copy of the GNU General Public
20 * License along with this program; if not, write to the
21 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
22 * Boston, MA 021110-1307, USA.
26 #include <linux/init.h>
27 #include <linux/types.h>
29 #define MLOG_MASK_PREFIX ML_EXTENT_MAP
30 #include <cluster/masklog.h>
35 #include "extent_map.h"
39 #include "buffer_head_io.h"
42 * Return the index of the extent record which contains cluster #v_cluster.
43 * -1 is returned if it was not found.
45 * Should work fine on interior and exterior nodes.
47 static int ocfs2_search_extent_list(struct ocfs2_extent_list
*el
,
52 struct ocfs2_extent_rec
*rec
;
53 u32 rec_end
, rec_start
;
55 for(i
= 0; i
< le16_to_cpu(el
->l_next_free_rec
); i
++) {
58 rec_start
= le32_to_cpu(rec
->e_cpos
);
59 rec_end
= rec_start
+ le32_to_cpu(rec
->e_clusters
);
61 if (v_cluster
>= rec_start
&& v_cluster
< rec_end
) {
70 int ocfs2_get_clusters(struct inode
*inode
, u32 v_cluster
,
71 u32
*p_cluster
, u32
*num_clusters
)
74 struct buffer_head
*di_bh
= NULL
;
75 struct buffer_head
*eb_bh
= NULL
;
76 struct ocfs2_dinode
*di
;
77 struct ocfs2_extent_block
*eb
;
78 struct ocfs2_extent_list
*el
;
79 struct ocfs2_extent_rec
*rec
;
82 ret
= ocfs2_read_block(OCFS2_SB(inode
->i_sb
), OCFS2_I(inode
)->ip_blkno
,
83 &di_bh
, OCFS2_BH_CACHED
, inode
);
89 di
= (struct ocfs2_dinode
*) di_bh
->b_data
;
92 if (el
->l_tree_depth
) {
93 ret
= ocfs2_find_leaf(inode
, el
, v_cluster
, &eb_bh
);
99 eb
= (struct ocfs2_extent_block
*) eb_bh
->b_data
;
103 i
= ocfs2_search_extent_list(el
, v_cluster
);
106 * A hole was found. Return some canned values that
107 * callers can key on.
113 rec
= &el
->l_recs
[i
];
115 BUG_ON(v_cluster
< le32_to_cpu(rec
->e_cpos
));
118 ocfs2_error(inode
->i_sb
, "Inode %lu has bad extent "
119 "record (%u, %u, 0)", inode
->i_ino
,
120 le32_to_cpu(rec
->e_cpos
),
121 le32_to_cpu(rec
->e_clusters
));
126 coff
= v_cluster
- le32_to_cpu(rec
->e_cpos
);
128 *p_cluster
= ocfs2_blocks_to_clusters(inode
->i_sb
,
129 le64_to_cpu(rec
->e_blkno
));
130 *p_cluster
= *p_cluster
+ coff
;
133 *num_clusters
= le32_to_cpu(rec
->e_clusters
) - coff
;
143 * This expects alloc_sem to be held. The allocation cannot change at
144 * all while the map is in the process of being updated.
146 int ocfs2_extent_map_get_blocks(struct inode
*inode
, u64 v_blkno
, u64
*p_blkno
,
150 int bpc
= ocfs2_clusters_to_blocks(inode
->i_sb
, 1);
151 u32 cpos
, num_clusters
, p_cluster
;
154 cpos
= ocfs2_blocks_to_clusters(inode
->i_sb
, v_blkno
);
156 ret
= ocfs2_get_clusters(inode
, cpos
, &p_cluster
, &num_clusters
);
163 * p_cluster == 0 indicates a hole.
166 boff
= ocfs2_clusters_to_blocks(inode
->i_sb
, p_cluster
);
167 boff
+= (v_blkno
& (u64
)(bpc
- 1));
173 *ret_count
= ocfs2_clusters_to_blocks(inode
->i_sb
, num_clusters
);
174 *ret_count
-= v_blkno
& (u64
)(bpc
- 1);
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