source: mainline/uspace/lib/ext4/libext4_filesystem.c@ acd869e

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since acd869e was acd869e, checked in by Frantisek Princ <frantisek.princ@…>, 14 years ago

Preparations for extent reading
  • Property mode set to 100644
File size: 9.6 KB
Line 
1/*
2 * Copyright (c) 2011 Frantisek Princ
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** @addtogroup libext4
30 * @{
31 */
32
33/**
34 * @file libext4_filesystem.c
35 * @brief TODO
36 */
37
38#include <byteorder.h>
39#include <errno.h>
40#include <malloc.h>
41#include "libext4.h"
42
43int ext4_filesystem_init(ext4_filesystem_t *fs, service_id_t service_id)
44{
45
46 int rc;
47 ext4_superblock_t *temp_superblock;
48 size_t block_size;
49
50 fs->device = service_id;
51
52 // TODO what does constant 2048 mean?
53 rc = block_init(EXCHANGE_SERIALIZE, fs->device, 2048);
54 if (rc != EOK) {
55 return rc;
56 }
57
58 /* Read superblock from device */
59 rc = ext4_superblock_read_direct(fs->device, &temp_superblock);
60 if (rc != EOK) {
61 block_fini(fs->device);
62 return rc;
63 }
64
65 /* Read block size from superblock and check */
66 block_size = ext4_superblock_get_block_size(temp_superblock);
67 if (block_size > EXT4_MAX_BLOCK_SIZE) {
68 block_fini(fs->device);
69 return ENOTSUP;
70 }
71
72 /* Initialize block caching */
73 rc = block_cache_init(service_id, block_size, 0, CACHE_MODE_WT);
74 if (rc != EOK) {
75 block_fini(fs->device);
76 return rc;
77 }
78
79 /* Return loaded superblock */
80 fs->superblock = temp_superblock;
81
82 return EOK;
83}
84
85void ext4_filesystem_fini(ext4_filesystem_t *fs)
86{
87 free(fs->superblock);
88 block_fini(fs->device);
89}
90
91int ext4_filesystem_check_sanity(ext4_filesystem_t *fs)
92{
93 int rc;
94
95 rc = ext4_superblock_check_sanity(fs->superblock);
96 if (rc != EOK) {
97 return rc;
98 }
99
100 return EOK;
101}
102
103int ext4_filesystem_check_features(ext4_filesystem_t *fs, bool *o_read_only)
104{
105 /* Feature flags are present in rev 1 and later */
106 if (ext4_superblock_get_rev_level(fs->superblock) == 0) {
107 *o_read_only = false;
108 return EOK;
109 }
110
111 uint32_t incompatible_features;
112 incompatible_features = ext4_superblock_get_features_incompatible(fs->superblock);
113 incompatible_features &= ~EXT4_FEATURE_INCOMPAT_SUPP;
114 if (incompatible_features > 0) {
115 *o_read_only = true;
116 return ENOTSUP;
117 }
118
119 uint32_t compatible_read_only;
120 compatible_read_only = ext4_superblock_get_features_read_only(fs->superblock);
121 compatible_read_only &= ~EXT4_FEATURE_RO_COMPAT_SUPP;
122 if (compatible_read_only > 0) {
123 *o_read_only = true;
124 }
125
126 return EOK;
127}
128
129// Feature checkers
130bool ext4_filesystem_has_feature_compatible(ext4_filesystem_t *fs, uint32_t feature)
131{
132 ext4_superblock_t *sb = fs->superblock;
133
134 if (ext4_superblock_get_features_compatible(sb) & feature) {
135 return true;
136 }
137 return false;
138}
139
140bool ext4_filesystem_has_feature_incompatible(ext4_filesystem_t *fs, uint32_t feature)
141{
142 ext4_superblock_t *sb = fs->superblock;
143
144 if (ext4_superblock_get_features_incompatible(sb) & feature) {
145 return true;
146 }
147 return false;
148}
149
150bool ext4_filesystem_has_feature_read_only(ext4_filesystem_t *fs, uint32_t feature)
151{
152 ext4_superblock_t *sb = fs->superblock;
153
154 if (ext4_superblock_get_features_read_only(sb) & feature) {
155 return true;
156 }
157 return false;
158}
159
160
161int ext4_filesystem_get_block_group_ref(ext4_filesystem_t *fs, uint32_t bgid,
162 ext4_block_group_ref_t **ref)
163{
164 int rc;
165 aoff64_t block_id;
166 uint32_t descriptors_per_block;
167 size_t offset;
168 ext4_block_group_ref_t *newref;
169
170 newref = malloc(sizeof(ext4_block_group_ref_t));
171 if (newref == NULL) {
172 return ENOMEM;
173 }
174
175 descriptors_per_block = ext4_superblock_get_block_size(fs->superblock)
176 / EXT4_BLOCK_GROUP_DESCRIPTOR_SIZE;
177
178 /* Block group descriptor table starts at the next block after superblock */
179 block_id = ext4_superblock_get_first_data_block(fs->superblock) + 1;
180
181 /* Find the block containing the descriptor we are looking for */
182 block_id += bgid / descriptors_per_block;
183 offset = (bgid % descriptors_per_block) * EXT4_BLOCK_GROUP_DESCRIPTOR_SIZE;
184
185 rc = block_get(&newref->block, fs->device, block_id, 0);
186 if (rc != EOK) {
187 free(newref);
188 return rc;
189 }
190
191 newref->block_group = newref->block->data + offset;
192
193 *ref = newref;
194
195 return EOK;
196}
197
198int ext4_filesystem_put_block_group_ref(ext4_block_group_ref_t *ref)
199{
200 int rc;
201
202 rc = block_put(ref->block);
203 free(ref);
204
205 return rc;
206}
207
208int ext4_filesystem_get_inode_ref(ext4_filesystem_t *fs, uint32_t index,
209 ext4_inode_ref_t **ref)
210{
211 int rc;
212 aoff64_t block_id;
213 uint32_t block_group;
214 uint32_t offset_in_group;
215 uint32_t byte_offset_in_group;
216 size_t offset_in_block;
217 uint32_t inodes_per_group;
218 uint32_t inode_table_start;
219 uint16_t inode_size;
220 uint32_t block_size;
221 ext4_block_group_ref_t *bg_ref;
222 ext4_inode_ref_t *newref;
223
224 newref = malloc(sizeof(ext4_inode_ref_t));
225 if (newref == NULL) {
226 return ENOMEM;
227 }
228
229 inodes_per_group = ext4_superblock_get_inodes_per_group(fs->superblock);
230
231 /* inode numbers are 1-based, but it is simpler to work with 0-based
232 * when computing indices
233 */
234 index -= 1;
235 block_group = index / inodes_per_group;
236 offset_in_group = index % inodes_per_group;
237
238 rc = ext4_filesystem_get_block_group_ref(fs, block_group, &bg_ref);
239 if (rc != EOK) {
240 free(newref);
241 return rc;
242 }
243
244 inode_table_start = ext4_block_group_get_inode_table_first_block(
245 bg_ref->block_group);
246
247 rc = ext4_filesystem_put_block_group_ref(bg_ref);
248 if (rc != EOK) {
249 free(newref);
250 return rc;
251 }
252
253 inode_size = ext4_superblock_get_inode_size(fs->superblock);
254 block_size = ext4_superblock_get_block_size(fs->superblock);
255
256 byte_offset_in_group = offset_in_group * inode_size;
257
258 block_id = inode_table_start + (byte_offset_in_group / block_size);
259 offset_in_block = byte_offset_in_group % block_size;
260
261 rc = block_get(&newref->block, fs->device, block_id, 0);
262 if (rc != EOK) {
263 free(newref);
264 return rc;
265 }
266
267 newref->inode = newref->block->data + offset_in_block;
268 /* we decremented index above, but need to store the original value
269 * in the reference
270 */
271 newref->index = index+1;
272
273 *ref = newref;
274
275 return EOK;
276}
277
278
279int ext4_filesystem_put_inode_ref(ext4_inode_ref_t *ref)
280{
281 int rc;
282
283 rc = block_put(ref->block);
284 free(ref);
285
286 return rc;
287}
288
289int ext4_filesystem_get_inode_data_block_index(ext4_filesystem_t *fs, ext4_inode_t* inode,
290 aoff64_t iblock, uint32_t* fblock)
291{
292 int rc;
293 aoff64_t limits[4];
294 uint32_t block_ids_per_block;
295 aoff64_t blocks_per_level[4];
296 uint32_t offset_in_block;
297 uint32_t current_block;
298 aoff64_t block_offset_in_level;
299 int i;
300 int level;
301 block_t *block;
302
303 // TODO extents
304 if (ext4_inode_has_flag(inode, EXT4_INODE_FLAG_EXTENTS)) {
305 EXT4FS_DBG("Inode contains Extent");
306 // TODO
307 /*
308 current_block = ext4_inode_get_extent_block(inode, iblock);
309 *fblock = current_block;
310 return EOK;
311 */
312
313 }
314
315 /* Handle simple case when we are dealing with direct reference */
316 if (iblock < EXT4_INODE_DIRECT_BLOCK_COUNT) {
317 current_block = ext4_inode_get_direct_block(inode, (uint32_t)iblock);
318 *fblock = current_block;
319 return EOK;
320 }
321
322 /* Compute limits for indirect block levels
323 * TODO: compute this once when loading filesystem and store in ext2_filesystem_t
324 */
325 block_ids_per_block = ext4_superblock_get_block_size(fs->superblock) / sizeof(uint32_t);
326 limits[0] = EXT4_INODE_DIRECT_BLOCK_COUNT;
327 blocks_per_level[0] = 1;
328 for (i = 1; i < 4; i++) {
329 blocks_per_level[i] = blocks_per_level[i-1] *
330 block_ids_per_block;
331 limits[i] = limits[i-1] + blocks_per_level[i];
332 }
333
334 /* Determine the indirection level needed to get the desired block */
335 level = -1;
336 for (i = 1; i < 4; i++) {
337 if (iblock < limits[i]) {
338 level = i;
339 break;
340 }
341 }
342
343 if (level == -1) {
344 return EIO;
345 }
346
347 /* Compute offsets for the topmost level */
348 block_offset_in_level = iblock - limits[level-1];
349 current_block = ext4_inode_get_indirect_block(inode, level-1);
350 offset_in_block = block_offset_in_level / blocks_per_level[level-1];
351
352 /* Navigate through other levels, until we find the block number
353 * or find null reference meaning we are dealing with sparse file
354 */
355 while (level > 0) {
356 rc = block_get(&block, fs->device, current_block, 0);
357 if (rc != EOK) {
358 return rc;
359 }
360
361 assert(offset_in_block < block_ids_per_block);
362 current_block = uint32_t_le2host(((uint32_t*)block->data)[offset_in_block]);
363
364 rc = block_put(block);
365 if (rc != EOK) {
366 return rc;
367 }
368
369 if (current_block == 0) {
370 /* This is a sparse file */
371 *fblock = 0;
372 return EOK;
373 }
374
375 level -= 1;
376
377 /* If we are on the last level, break here as
378 * there is no next level to visit
379 */
380 if (level == 0) {
381 break;
382 }
383
384 /* Visit the next level */
385 block_offset_in_level %= blocks_per_level[level];
386 offset_in_block = block_offset_in_level / blocks_per_level[level-1];
387 }
388
389 *fblock = current_block;
390
391 return EOK;
392}
393
394/**
395 * @}
396 */
Note: See TracBrowser for help on using the repository browser.