source: mainline/uspace/lib/ext4/libext4_filesystem.c@ 8958a26

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 8958a26 was 8958a26, checked in by Frantisek Princ <frantisek.princ@…>, 14 years ago

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[6c501f8]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
[9b9d37bb]38#include <byteorder.h>
[6c501f8]39#include <errno.h>
[01ab41b]40#include <malloc.h>
[3711e7e]41#include "libext4.h"
[6c501f8]42
43int ext4_filesystem_init(ext4_filesystem_t *fs, service_id_t service_id)
44{
[01ab41b]45
46 int rc;
47 ext4_superblock_t *temp_superblock;
48 size_t block_size;
49
50 fs->device = service_id;
51
[9c0c0e1]52 // TODO what does constant 2048 mean?
[01ab41b]53 rc = block_init(EXCHANGE_SERIALIZE, fs->device, 2048);
54 if (rc != EOK) {
55 return rc;
56 }
57
[9c0c0e1]58 /* Read superblock from device */
[01ab41b]59 rc = ext4_superblock_read_direct(fs->device, &temp_superblock);
60 if (rc != EOK) {
61 block_fini(fs->device);
62 return rc;
63 }
64
[9c0c0e1]65 /* Read block size from superblock and check */
[01ab41b]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
[9c0c0e1]72 /* Initialize block caching */
[01ab41b]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
[9c0c0e1]79 /* Return loaded superblock */
[01ab41b]80 fs->superblock = temp_superblock;
81
[6c501f8]82 return EOK;
83}
84
[3711e7e]85void ext4_filesystem_fini(ext4_filesystem_t *fs)
86{
87 free(fs->superblock);
88 block_fini(fs->device);
89}
90
[6c501f8]91int ext4_filesystem_check_sanity(ext4_filesystem_t *fs)
92{
[01ab41b]93 int rc;
94
95 rc = ext4_superblock_check_sanity(fs->superblock);
96 if (rc != EOK) {
97 return rc;
98 }
99
[6c501f8]100 return EOK;
101}
102
[9c0c0e1]103int ext4_filesystem_check_features(ext4_filesystem_t *fs, bool *o_read_only)
[6c501f8]104{
[9c0c0e1]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
[6c501f8]126 return EOK;
127}
128
[2ea6392]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
[3711e7e]161int ext4_filesystem_get_block_group_ref(ext4_filesystem_t *fs, uint32_t bgid,
162 ext4_block_group_ref_t **ref)
[6c501f8]163{
[3711e7e]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 */
[3712434]179 block_id = ext4_superblock_get_first_data_block(fs->superblock) + 1;
[3711e7e]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;
[6c501f8]196}
197
[829d238]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
[3711e7e]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
[829d238]247 rc = ext4_filesystem_put_block_group_ref(bg_ref);
248 if (rc != EOK) {
249 free(newref);
250 return rc;
251 }
252
[3711e7e]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
[9b9d37bb]275 return EOK;
276}
277
[e68c834]278
[9b9d37bb]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
[8958a26]303 /* Handle inode using extents */
304 // TODO check "extents" feature in superblock ???
[acd869e]305 if (ext4_inode_has_flag(inode, EXT4_INODE_FLAG_EXTENTS)) {
306 current_block = ext4_inode_get_extent_block(inode, iblock);
307 *fblock = current_block;
308 return EOK;
309
310 }
311
[9b9d37bb]312 /* Handle simple case when we are dealing with direct reference */
[e68c834]313 if (iblock < EXT4_INODE_DIRECT_BLOCK_COUNT) {
[9b9d37bb]314 current_block = ext4_inode_get_direct_block(inode, (uint32_t)iblock);
315 *fblock = current_block;
316 return EOK;
317 }
318
319 /* Compute limits for indirect block levels
320 * TODO: compute this once when loading filesystem and store in ext2_filesystem_t
321 */
322 block_ids_per_block = ext4_superblock_get_block_size(fs->superblock) / sizeof(uint32_t);
[e68c834]323 limits[0] = EXT4_INODE_DIRECT_BLOCK_COUNT;
[9b9d37bb]324 blocks_per_level[0] = 1;
325 for (i = 1; i < 4; i++) {
326 blocks_per_level[i] = blocks_per_level[i-1] *
327 block_ids_per_block;
328 limits[i] = limits[i-1] + blocks_per_level[i];
329 }
330
331 /* Determine the indirection level needed to get the desired block */
332 level = -1;
333 for (i = 1; i < 4; i++) {
334 if (iblock < limits[i]) {
335 level = i;
336 break;
337 }
338 }
339
340 if (level == -1) {
341 return EIO;
342 }
343
344 /* Compute offsets for the topmost level */
345 block_offset_in_level = iblock - limits[level-1];
346 current_block = ext4_inode_get_indirect_block(inode, level-1);
347 offset_in_block = block_offset_in_level / blocks_per_level[level-1];
348
349 /* Navigate through other levels, until we find the block number
350 * or find null reference meaning we are dealing with sparse file
351 */
352 while (level > 0) {
353 rc = block_get(&block, fs->device, current_block, 0);
354 if (rc != EOK) {
355 return rc;
356 }
357
358 assert(offset_in_block < block_ids_per_block);
359 current_block = uint32_t_le2host(((uint32_t*)block->data)[offset_in_block]);
360
361 rc = block_put(block);
362 if (rc != EOK) {
363 return rc;
364 }
365
366 if (current_block == 0) {
367 /* This is a sparse file */
368 *fblock = 0;
369 return EOK;
370 }
371
372 level -= 1;
373
374 /* If we are on the last level, break here as
375 * there is no next level to visit
376 */
377 if (level == 0) {
378 break;
379 }
380
381 /* Visit the next level */
382 block_offset_in_level %= blocks_per_level[level];
383 offset_in_block = block_offset_in_level / blocks_per_level[level-1];
384 }
385
386 *fblock = current_block;
387
[3711e7e]388 return EOK;
389}
[6c501f8]390
391/**
392 * @}
393 */
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