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gerrit.nordix.org / codeaurora / busybox / 28de951b022d39516de271ce0ba53560aa3c5555 / . / e2fsprogs / ext2fs / bmap.c
blob: e84004476f341adc5d751e2129f4cbfe9f9abae2 [file] [log] [blame]
Mike Frysinger1fd98e02005-05-09 22:10:42 +0000[diff] [blame]1/*
2 * bmap.c --- logical to physical block mapping
3 *
4 * Copyright (C) 1997 Theodore Ts'o.
5 *
6 * %Begin-Header%
7 * This file may be redistributed under the terms of the GNU Public
8 * License.
9 * %End-Header%
10 */
11
12#include <stdio.h>
13#include <string.h>
14#if HAVE_UNISTD_H
15#include <unistd.h>
16#endif
17
18#include "ext2_fs.h"
19#include "ext2fs.h"
20
21#if defined(__GNUC__) && !defined(NO_INLINE_FUNCS)
22#define _BMAP_INLINE_ __inline__
23#else
24#define _BMAP_INLINE_
25#endif
26
27extern errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino,
28 struct ext2_inode *inode,
29 char *block_buf, int bmap_flags,
30 blk_t block, blk_t *phys_blk);
31
32#define inode_bmap(inode, nr) ((inode)->i_block[(nr)])
33
34static _BMAP_INLINE_ errcode_t block_ind_bmap(ext2_filsys fs, int flags,
35 blk_t ind, char *block_buf,
36 int *blocks_alloc,
37 blk_t nr, blk_t *ret_blk)
38{
39 errcode_t retval;
40 blk_t b;
41
42 if (!ind) {
43 if (flags & BMAP_SET)
44 return EXT2_ET_SET_BMAP_NO_IND;
45 *ret_blk = 0;
46 return 0;
47 }
48 retval = io_channel_read_blk(fs->io, ind, 1, block_buf);
49 if (retval)
50 return retval;
51
52 if (flags & BMAP_SET) {
53 b = *ret_blk;
54#ifdef EXT2FS_ENABLE_SWAPFS
55 if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
56 (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
57 b = ext2fs_swab32(b);
58#endif
59 ((blk_t *) block_buf)[nr] = b;
60 return io_channel_write_blk(fs->io, ind, 1, block_buf);
61 }
62
63 b = ((blk_t *) block_buf)[nr];
64
65#ifdef EXT2FS_ENABLE_SWAPFS
66 if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
67 (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
68 b = ext2fs_swab32(b);
69#endif
70
71 if (!b && (flags & BMAP_ALLOC)) {
72 b = nr ? ((blk_t *) block_buf)[nr-1] : 0;
73 retval = ext2fs_alloc_block(fs, b,
74 block_buf + fs->blocksize, &b);
75 if (retval)
76 return retval;
77
78#ifdef EXT2FS_ENABLE_SWAPFS
79 if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
80 (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
81 ((blk_t *) block_buf)[nr] = ext2fs_swab32(b);
82 else
83#endif
84 ((blk_t *) block_buf)[nr] = b;
85
86 retval = io_channel_write_blk(fs->io, ind, 1, block_buf);
87 if (retval)
88 return retval;
89
90 (*blocks_alloc)++;
91 }
92
93 *ret_blk = b;
94 return 0;
95}
96
97static _BMAP_INLINE_ errcode_t block_dind_bmap(ext2_filsys fs, int flags,
98 blk_t dind, char *block_buf,
99 int *blocks_alloc,
100 blk_t nr, blk_t *ret_blk)
101{
102 blk_t b;
103 errcode_t retval;
104 blk_t addr_per_block;
105
106 addr_per_block = (blk_t) fs->blocksize >> 2;
107
108 retval = block_ind_bmap(fs, flags & ~BMAP_SET, dind, block_buf,
109 blocks_alloc, nr / addr_per_block, &b);
110 if (retval)
111 return retval;
112 retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
113 nr % addr_per_block, ret_blk);
114 return retval;
115}
116
117static _BMAP_INLINE_ errcode_t block_tind_bmap(ext2_filsys fs, int flags,
118 blk_t tind, char *block_buf,
119 int *blocks_alloc,
120 blk_t nr, blk_t *ret_blk)
121{
122 blk_t b;
123 errcode_t retval;
124 blk_t addr_per_block;
125
126 addr_per_block = (blk_t) fs->blocksize >> 2;
127
128 retval = block_dind_bmap(fs, flags & ~BMAP_SET, tind, block_buf,
129 blocks_alloc, nr / addr_per_block, &b);
130 if (retval)
131 return retval;
132 retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
133 nr % addr_per_block, ret_blk);
134 return retval;
135}
136
137errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
138 char *block_buf, int bmap_flags, blk_t block,
139 blk_t *phys_blk)
140{
141 struct ext2_inode inode_buf;
142 blk_t addr_per_block;
143 blk_t b;
144 char *buf = 0;
145 errcode_t retval = 0;
146 int blocks_alloc = 0, inode_dirty = 0;
147
148 if (!(bmap_flags & BMAP_SET))
149 *phys_blk = 0;
150
151 /* Read inode structure if necessary */
152 if (!inode) {
153 retval = ext2fs_read_inode(fs, ino, &inode_buf);
154 if (retval)
155 return retval;
156 inode = &inode_buf;
157 }
158 addr_per_block = (blk_t) fs->blocksize >> 2;
159
160 if (!block_buf) {
161 retval = ext2fs_get_mem(fs->blocksize * 2, &buf);
162 if (retval)
163 return retval;
164 block_buf = buf;
165 }
166
167 if (block < EXT2_NDIR_BLOCKS) {
168 if (bmap_flags & BMAP_SET) {
169 b = *phys_blk;
170#ifdef EXT2FS_ENABLE_SWAPFS
171 if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
172 (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
173 b = ext2fs_swab32(b);
174#endif
175 inode_bmap(inode, block) = b;
176 inode_dirty++;
177 goto done;
178 }
179
180 *phys_blk = inode_bmap(inode, block);
181 b = block ? inode_bmap(inode, block-1) : 0;
182
183 if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) {
184 retval = ext2fs_alloc_block(fs, b, block_buf, &b);
185 if (retval)
186 goto done;
187 inode_bmap(inode, block) = b;
188 blocks_alloc++;
189 *phys_blk = b;
190 }
191 goto done;
192 }
193
194 /* Indirect block */
195 block -= EXT2_NDIR_BLOCKS;
196 if (block < addr_per_block) {
197 b = inode_bmap(inode, EXT2_IND_BLOCK);
198 if (!b) {
199 if (!(bmap_flags & BMAP_ALLOC)) {
200 if (bmap_flags & BMAP_SET)
201 retval = EXT2_ET_SET_BMAP_NO_IND;
202 goto done;
203 }
204
205 b = inode_bmap(inode, EXT2_IND_BLOCK-1);
206 retval = ext2fs_alloc_block(fs, b, block_buf, &b);
207 if (retval)
208 goto done;
209 inode_bmap(inode, EXT2_IND_BLOCK) = b;
210 blocks_alloc++;
211 }
212 retval = block_ind_bmap(fs, bmap_flags, b, block_buf,
213 &blocks_alloc, block, phys_blk);
214 goto done;
215 }
216
217 /* Doubly indirect block */
218 block -= addr_per_block;
219 if (block < addr_per_block * addr_per_block) {
220 b = inode_bmap(inode, EXT2_DIND_BLOCK);
221 if (!b) {
222 if (!(bmap_flags & BMAP_ALLOC)) {
223 if (bmap_flags & BMAP_SET)
224 retval = EXT2_ET_SET_BMAP_NO_IND;
225 goto done;
226 }
227
228 b = inode_bmap(inode, EXT2_IND_BLOCK);
229 retval = ext2fs_alloc_block(fs, b, block_buf, &b);
230 if (retval)
231 goto done;
232 inode_bmap(inode, EXT2_DIND_BLOCK) = b;
233 blocks_alloc++;
234 }
235 retval = block_dind_bmap(fs, bmap_flags, b, block_buf,
236 &blocks_alloc, block, phys_blk);
237 goto done;
238 }
239
240 /* Triply indirect block */
241 block -= addr_per_block * addr_per_block;
242 b = inode_bmap(inode, EXT2_TIND_BLOCK);
243 if (!b) {
244 if (!(bmap_flags & BMAP_ALLOC)) {
245 if (bmap_flags & BMAP_SET)
246 retval = EXT2_ET_SET_BMAP_NO_IND;
247 goto done;
248 }
249
250 b = inode_bmap(inode, EXT2_DIND_BLOCK);
251 retval = ext2fs_alloc_block(fs, b, block_buf, &b);
252 if (retval)
253 goto done;
254 inode_bmap(inode, EXT2_TIND_BLOCK) = b;
255 blocks_alloc++;
256 }
257 retval = block_tind_bmap(fs, bmap_flags, b, block_buf,
258 &blocks_alloc, block, phys_blk);
259done:
260 if (buf)
261 ext2fs_free_mem(&buf);
262 if ((retval == 0) && (blocks_alloc || inode_dirty)) {
263 inode->i_blocks += (blocks_alloc * fs->blocksize) / 512;
264 retval = ext2fs_write_inode(fs, ino, inode);
265 }
266 return retval;
267}
268
269
270