source: mainline/uspace/srv/fs/mfs/mfs_rw.c@ 4e00f87

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 4e00f87 was e895352, checked in by Maurizio Lombardi <m.lombardi85@…>, 14 years ago

cstyle, fix typo
  • Property mode set to 100644
File size: 9.7 KB
Line 
1/*
2 * Copyright (c) 2011 Maurizio Lombardi
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 fs
30 * @{
31 */
32
33#include <align.h>
34#include "mfs.h"
35
36static int
37rw_map_ondisk(uint32_t *b, const struct mfs_node *mnode, int rblock,
38 bool write_mode, uint32_t w_block);
39
40static int
41reset_zone_content(struct mfs_instance *inst, uint32_t zone);
42
43static int
44alloc_zone_and_clear(struct mfs_instance *inst, uint32_t *zone);
45
46static int
47read_ind_zone(struct mfs_instance *inst, uint32_t zone, uint32_t **ind_zone);
48
49static int
50write_ind_zone(struct mfs_instance *inst, uint32_t zone, uint32_t *ind_zone);
51
52
53/**Given the position in the file expressed in
54 *bytes, this function returns the on-disk block
55 *relative to that position.
56 *
57 * @param b Pointer to a 32bit number where the block number will be stored
58 * @param mnode Pointer to a generic MINIX inode in memory.
59 * @param pos Position in file.
60 *
61 * @return EOK on success or a negative error code.
62 */
63int
64mfs_read_map(uint32_t *b, const struct mfs_node *mnode, uint32_t pos)
65{
66 int r;
67 const struct mfs_sb_info *sbi = mnode->instance->sbi;
68 const int block_size = sbi->block_size;
69
70 /* Compute relative block number in file */
71 int rblock = pos / block_size;
72
73 if (ROUND_UP(mnode->ino_i->i_size, sbi->block_size) < pos) {
74 /* Trying to read beyond the end of file */
75 r = EOK;
76 *b = 0;
77 goto out;
78 }
79
80 r = rw_map_ondisk(b, mnode, rblock, false, 0);
81out:
82 return r;
83}
84
85int
86mfs_write_map(struct mfs_node *mnode, const uint32_t pos, uint32_t new_zone,
87 uint32_t *old_zone)
88{
89 const struct mfs_sb_info *sbi = mnode->instance->sbi;
90
91 if (pos >= sbi->max_file_size) {
92 /* Can't write beyond the maximum file size */
93 return EINVAL;
94 }
95
96 /* Compute the relative block number in file */
97 int rblock = pos / sbi->block_size;
98
99 return rw_map_ondisk(old_zone, mnode, rblock, true, new_zone);
100}
101
102static int
103rw_map_ondisk(uint32_t *b, const struct mfs_node *mnode, int rblock,
104 bool write_mode, uint32_t w_block)
105{
106 int r, nr_direct;
107 int ptrs_per_block;
108 uint32_t *ind_zone, *ind2_zone;
109
110 struct mfs_ino_info *ino_i = mnode->ino_i;
111 struct mfs_instance *inst = mnode->instance;
112 struct mfs_sb_info *sbi = inst->sbi;
113
114 const mfs_version_t fs_version = sbi->fs_version;
115 const bool deleting = write_mode && (w_block == 0);
116
117 if (fs_version == MFS_VERSION_V1) {
118 nr_direct = V1_NR_DIRECT_ZONES;
119 ptrs_per_block = MFS_BLOCKSIZE / sizeof(uint16_t);
120 } else {
121 nr_direct = V2_NR_DIRECT_ZONES;
122 ptrs_per_block = sbi->block_size / sizeof(uint32_t);
123 }
124
125 /* Check if the wanted block is in the direct zones */
126 if (rblock < nr_direct) {
127 *b = ino_i->i_dzone[rblock];
128 if (write_mode) {
129 ino_i->i_dzone[rblock] = w_block;
130 ino_i->dirty = true;
131 }
132 return EOK;
133 }
134
135 rblock -= nr_direct;
136
137 if (rblock < ptrs_per_block) {
138 /* The wanted block is in the single indirect zone chain */
139 if (ino_i->i_izone[0] == 0) {
140 if (write_mode && !deleting) {
141 uint32_t zone;
142 r = alloc_zone_and_clear(inst, &zone);
143 if (r != EOK)
144 return r;
145
146 ino_i->i_izone[0] = zone;
147 ino_i->dirty = true;
148 } else {
149 /* Sparse block */
150 *b = 0;
151 return EOK;
152 }
153 }
154
155 r = read_ind_zone(inst, ino_i->i_izone[0], &ind_zone);
156 if (r != EOK)
157 return r;
158
159 *b = ind_zone[rblock];
160 if (write_mode) {
161 ind_zone[rblock] = w_block;
162 write_ind_zone(inst, ino_i->i_izone[0], ind_zone);
163 }
164
165 goto out_free_ind1;
166 }
167
168 rblock -= ptrs_per_block;
169
170 /* The wanted block is in the double indirect zone chain */
171
172 /* Read the first indirect zone of the chain */
173 if (ino_i->i_izone[1] == 0) {
174 if (write_mode && !deleting) {
175 uint32_t zone;
176 r = alloc_zone_and_clear(inst, &zone);
177 if (r != EOK)
178 return r;
179
180 ino_i->i_izone[1] = zone;
181 ino_i->dirty = true;
182 } else {
183 /* Sparse block */
184 *b = 0;
185 return EOK;
186 }
187 }
188
189 r = read_ind_zone(inst, ino_i->i_izone[1], &ind_zone);
190 if (r != EOK)
191 return r;
192
193 /*
194 * Compute the position of the second indirect
195 * zone pointer in the chain.
196 */
197 uint32_t ind2_off = rblock / ptrs_per_block;
198
199 /* read the second indirect zone of the chain */
200 if (ind_zone[ind2_off] == 0) {
201 if (write_mode && !deleting) {
202 uint32_t zone;
203 r = alloc_zone_and_clear(inst, &zone);
204 if (r != EOK)
205 goto out_free_ind1;
206
207 ind_zone[ind2_off] = zone;
208 write_ind_zone(inst, ino_i->i_izone[1], ind_zone);
209 } else {
210 /* Sparse block */
211 r = EOK;
212 *b = 0;
213 goto out_free_ind1;
214 }
215 }
216
217 r = read_ind_zone(inst, ind_zone[ind2_off], &ind2_zone);
218 if (r != EOK)
219 goto out_free_ind1;
220
221 *b = ind2_zone[rblock - (ind2_off * ptrs_per_block)];
222 if (write_mode) {
223 ind2_zone[rblock - (ind2_off * ptrs_per_block)] = w_block;
224 write_ind_zone(inst, ind_zone[ind2_off], ind2_zone);
225 }
226
227 r = EOK;
228
229 free(ind2_zone);
230out_free_ind1:
231 free(ind_zone);
232 return r;
233}
234
235/**Free unused indirect zones from a MINIX inode according to its new size.
236 *
237 * @param mnode Pointer to a generic MINIX inode in memory.
238 * @param new_size The new size of the inode.
239 *
240 * @return EOK on success or a negative error code.
241 */
242int
243mfs_prune_ind_zones(struct mfs_node *mnode, size_t new_size)
244{
245 struct mfs_instance *inst = mnode->instance;
246 struct mfs_sb_info *sbi = inst->sbi;
247 struct mfs_ino_info *ino_i = mnode->ino_i;
248 int nr_direct, ptrs_per_block, rblock, r;
249 int i;
250
251 mfs_version_t fs_version = sbi->fs_version;
252
253 assert(new_size <= ino_i->i_size);
254
255 if (fs_version == MFS_VERSION_V1) {
256 nr_direct = V1_NR_DIRECT_ZONES;
257 ptrs_per_block = MFS_BLOCKSIZE / sizeof(uint16_t);
258 } else {
259 nr_direct = V2_NR_DIRECT_ZONES;
260 ptrs_per_block = sbi->block_size / sizeof(uint32_t);
261 }
262
263 rblock = new_size / sbi->block_size;
264
265 if (rblock < nr_direct) {
266 /* Free the single indirect zone */
267 if (ino_i->i_izone[0]) {
268 r = mfs_free_zone(inst, ino_i->i_izone[0]);
269 if (r != EOK)
270 return r;
271
272 ino_i->i_izone[0] = 0;
273 ino_i->dirty = true;
274 }
275 }
276
277 rblock -= nr_direct + ptrs_per_block;
278
279 int fzone_to_free = (rblock < 0 ? 0 : rblock) / ptrs_per_block;
280
281 if ((fzone_to_free % ptrs_per_block) != 0)
282 ++fzone_to_free;
283
284 /* Free the entire double indirect zone */
285 uint32_t *dbl_zone;
286
287 if (ino_i->i_izone[1] == 0) {
288 /* Nothing to be done */
289 return EOK;
290 }
291
292 r = read_ind_zone(inst, ino_i->i_izone[1], &dbl_zone);
293 if (r != EOK)
294 return r;
295
296 for (i = fzone_to_free; i < ptrs_per_block; ++i) {
297 if (dbl_zone[i] == 0)
298 continue;
299
300 r = mfs_free_zone(inst, dbl_zone[i]);
301 if (r != EOK)
302 goto out;
303 }
304
305 if (fzone_to_free == 0) {
306 r = mfs_free_zone(inst, ino_i->i_izone[1]);
307 ino_i->i_izone[1] = 0;
308 ino_i->dirty = true;
309 }
310out:
311 free(dbl_zone);
312 return r;
313}
314
315static int
316reset_zone_content(struct mfs_instance *inst, uint32_t zone)
317{
318 block_t *b;
319 int r;
320
321 r = block_get(&b, inst->service_id, zone, BLOCK_FLAGS_NOREAD);
322 if (r != EOK)
323 return r;
324
325 memset(b->data, 0, b->size);
326 b->dirty = true;
327
328 return block_put(b);
329}
330
331static int
332alloc_zone_and_clear(struct mfs_instance *inst, uint32_t *zone)
333{
334 int r;
335
336 r = mfs_alloc_zone(inst, zone);
337 if (r != EOK)
338 return r;
339
340 r = reset_zone_content(inst, *zone);
341 return r;
342}
343
344static int
345read_ind_zone(struct mfs_instance *inst, uint32_t zone, uint32_t **ind_zone)
346{
347 struct mfs_sb_info *sbi = inst->sbi;
348 int r;
349 unsigned i;
350 block_t *b;
351 const int max_ind_zone_ptrs = (MFS_MAX_BLOCKSIZE / sizeof(uint16_t)) *
352 sizeof(uint32_t);
353
354 *ind_zone = malloc(max_ind_zone_ptrs);
355 if (*ind_zone == NULL)
356 return ENOMEM;
357
358 r = block_get(&b, inst->service_id, zone, BLOCK_FLAGS_NONE);
359 if (r != EOK) {
360 free(*ind_zone);
361 return r;
362 }
363
364 if (sbi->fs_version == MFS_VERSION_V1) {
365 uint16_t *src_ptr = b->data;
366
367 for (i = 0; i < sbi->block_size / sizeof(uint16_t); ++i)
368 (*ind_zone)[i] = conv16(sbi->native, src_ptr[i]);
369 } else {
370 uint32_t *src_ptr = b->data;
371
372 for (i = 0; i < sbi->block_size / sizeof(uint32_t); ++i)
373 (*ind_zone)[i] = conv32(sbi->native, src_ptr[i]);
374 }
375
376 return block_put(b);
377}
378
379static int
380write_ind_zone(struct mfs_instance *inst, uint32_t zone, uint32_t *ind_zone)
381{
382 struct mfs_sb_info *sbi = inst->sbi;
383 int r;
384 unsigned i;
385 block_t *b;
386
387 r = block_get(&b, inst->service_id, zone, BLOCK_FLAGS_NOREAD);
388 if (r != EOK)
389 return r;
390
391 if (sbi->fs_version == MFS_VERSION_V1) {
392 uint16_t *dest_ptr = b->data;
393
394 for (i = 0; i < sbi->block_size / sizeof(uint16_t); ++i)
395 dest_ptr[i] = conv16(sbi->native, ind_zone[i]);
396 } else {
397 uint32_t *dest_ptr = b->data;
398
399 for (i = 0; i < sbi->block_size / sizeof(uint32_t); ++i)
400 dest_ptr[i] = conv32(sbi->native, ind_zone[i]);
401
402 }
403 b->dirty = true;
404
405 return block_put(b);
406}
407
408
409/**
410 * @}
411 */
412
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