source: mainline/uspace/srv/fs/mfs/mfs_rw.c

Last change on this file was 09ab0a9a, checked in by Jiri Svoboda <jiri@…>, 7 years ago

Fix vertical spacing with new Ccheck revision.
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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 mfs
30 * @{
31 */
32
33#include <align.h>
34#include "mfs.h"
35
36static errno_t
37rw_map_ondisk(uint32_t *b, const struct mfs_node *mnode, int rblock,
38 bool write_mode, uint32_t w_block);
39
40static errno_t
41reset_zone_content(struct mfs_instance *inst, uint32_t zone);
42
43static errno_t
44alloc_zone_and_clear(struct mfs_instance *inst, uint32_t *zone);
45
46static errno_t
47read_ind_zone(struct mfs_instance *inst, uint32_t zone, uint32_t **ind_zone);
48
49static errno_t
50write_ind_zone(struct mfs_instance *inst, uint32_t zone, uint32_t *ind_zone);
51
52/**Given the position in the file expressed in
53 * bytes, this function returns the on-disk block
54 * relative to that position.
55 *
56 * @param b Pointer to a 32bit number where the block number will be stored
57 * @param mnode Pointer to a generic MINIX inode in memory.
58 * @param pos Position in file.
59 *
60 * @return EOK on success or an error code.
61 */
62errno_t
63mfs_read_map(uint32_t *b, const struct mfs_node *mnode, uint32_t pos)
64{
65 errno_t r;
66 const struct mfs_sb_info *sbi = mnode->instance->sbi;
67 const int block_size = sbi->block_size;
68
69 /* Compute relative block number in file */
70 int rblock = pos / block_size;
71
72 if (ROUND_UP(mnode->ino_i->i_size, sbi->block_size) < pos) {
73 /* Trying to read beyond the end of file */
74 r = EOK;
75 *b = 0;
76 goto out;
77 }
78
79 r = rw_map_ondisk(b, mnode, rblock, false, 0);
80out:
81 return r;
82}
83
84errno_t
85mfs_write_map(struct mfs_node *mnode, const uint32_t pos, uint32_t new_zone,
86 uint32_t *old_zone)
87{
88 const struct mfs_sb_info *sbi = mnode->instance->sbi;
89
90 if (pos >= sbi->max_file_size) {
91 /* Can't write beyond the maximum file size */
92 return EINVAL;
93 }
94
95 /* Compute the relative block number in file */
96 int rblock = pos / sbi->block_size;
97
98 return rw_map_ondisk(old_zone, mnode, rblock, true, new_zone);
99}
100
101static errno_t
102rw_map_ondisk(uint32_t *b, const struct mfs_node *mnode, int rblock,
103 bool write_mode, uint32_t w_block)
104{
105 int nr_direct;
106 int ptrs_per_block;
107 uint32_t *ind_zone = NULL, *ind2_zone = NULL;
108 errno_t r = EOK;
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 goto out;
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 goto out;
145
146 ino_i->i_izone[0] = zone;
147 ino_i->dirty = true;
148 } else {
149 /* Sparse block */
150 *b = 0;
151 goto out;
152 }
153 }
154
155 r = read_ind_zone(inst, ino_i->i_izone[0], &ind_zone);
156 if (r != EOK)
157 goto out;
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;
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 goto out;
179
180 ino_i->i_izone[1] = zone;
181 ino_i->dirty = true;
182 } else {
183 /* Sparse block */
184 *b = 0;
185 goto out;
186 }
187 }
188
189 r = read_ind_zone(inst, ino_i->i_izone[1], &ind_zone);
190 if (r != EOK)
191 goto out;
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;
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 *b = 0;
212 goto out;
213 }
214 }
215
216 r = read_ind_zone(inst, ind_zone[ind2_off], &ind2_zone);
217 if (r != EOK)
218 goto out;
219
220 *b = ind2_zone[rblock - (ind2_off * ptrs_per_block)];
221 if (write_mode) {
222 ind2_zone[rblock - (ind2_off * ptrs_per_block)] = w_block;
223 write_ind_zone(inst, ind_zone[ind2_off], ind2_zone);
224 }
225
226out:
227 free(ind2_zone);
228 free(ind_zone);
229 return r;
230}
231
232/**Free unused indirect zones from a MINIX inode according to its new size.
233 *
234 * @param mnode Pointer to a generic MINIX inode in memory.
235 * @param new_size The new size of the inode.
236 *
237 * @return EOK on success or an error code.
238 */
239errno_t
240mfs_prune_ind_zones(struct mfs_node *mnode, size_t new_size)
241{
242 struct mfs_instance *inst = mnode->instance;
243 struct mfs_sb_info *sbi = inst->sbi;
244 struct mfs_ino_info *ino_i = mnode->ino_i;
245 int nr_direct, ptrs_per_block, rblock;
246 errno_t r;
247 int i;
248
249 mfs_version_t fs_version = sbi->fs_version;
250
251 assert(new_size <= ino_i->i_size);
252
253 if (fs_version == MFS_VERSION_V1) {
254 nr_direct = V1_NR_DIRECT_ZONES;
255 ptrs_per_block = MFS_BLOCKSIZE / sizeof(uint16_t);
256 } else {
257 nr_direct = V2_NR_DIRECT_ZONES;
258 ptrs_per_block = sbi->block_size / sizeof(uint32_t);
259 }
260
261 rblock = new_size / sbi->block_size;
262
263 if (rblock < nr_direct) {
264 /* Free the single indirect zone */
265 if (ino_i->i_izone[0]) {
266 r = mfs_free_zone(inst, ino_i->i_izone[0]);
267 if (r != EOK)
268 return r;
269
270 ino_i->i_izone[0] = 0;
271 ino_i->dirty = true;
272 }
273 }
274
275 rblock -= nr_direct + ptrs_per_block;
276
277 int fzone_to_free = (rblock < 0 ? 0 : rblock) / ptrs_per_block;
278
279 if ((fzone_to_free % ptrs_per_block) != 0)
280 ++fzone_to_free;
281
282 /* Free the entire double indirect zone */
283 uint32_t *dbl_zone;
284
285 if (ino_i->i_izone[1] == 0) {
286 /* Nothing to be done */
287 return EOK;
288 }
289
290 r = read_ind_zone(inst, ino_i->i_izone[1], &dbl_zone);
291 if (r != EOK)
292 return r;
293
294 for (i = fzone_to_free; i < ptrs_per_block; ++i) {
295 if (dbl_zone[i] == 0)
296 continue;
297
298 r = mfs_free_zone(inst, dbl_zone[i]);
299 if (r != EOK)
300 goto out;
301 }
302
303 if (fzone_to_free == 0) {
304 r = mfs_free_zone(inst, ino_i->i_izone[1]);
305 ino_i->i_izone[1] = 0;
306 ino_i->dirty = true;
307 }
308out:
309 free(dbl_zone);
310 return r;
311}
312
313static errno_t
314reset_zone_content(struct mfs_instance *inst, uint32_t zone)
315{
316 block_t *b;
317 errno_t r;
318
319 r = block_get(&b, inst->service_id, zone, BLOCK_FLAGS_NOREAD);
320 if (r != EOK)
321 return r;
322
323 memset(b->data, 0, b->size);
324 b->dirty = true;
325
326 return block_put(b);
327}
328
329static errno_t
330alloc_zone_and_clear(struct mfs_instance *inst, uint32_t *zone)
331{
332 errno_t r;
333
334 r = mfs_alloc_zone(inst, zone);
335 if (r != EOK)
336 return r;
337
338 r = reset_zone_content(inst, *zone);
339 return r;
340}
341
342static errno_t
343read_ind_zone(struct mfs_instance *inst, uint32_t zone, uint32_t **ind_zone)
344{
345 struct mfs_sb_info *sbi = inst->sbi;
346 errno_t r;
347 unsigned i;
348 block_t *b;
349 const int max_ind_zone_ptrs = (MFS_MAX_BLOCKSIZE / sizeof(uint16_t)) *
350 sizeof(uint32_t);
351
352 *ind_zone = malloc(max_ind_zone_ptrs);
353 if (*ind_zone == NULL)
354 return ENOMEM;
355
356 r = block_get(&b, inst->service_id, zone, BLOCK_FLAGS_NONE);
357 if (r != EOK) {
358 free(*ind_zone);
359 return r;
360 }
361
362 if (sbi->fs_version == MFS_VERSION_V1) {
363 uint16_t *src_ptr = b->data;
364
365 for (i = 0; i < sbi->block_size / sizeof(uint16_t); ++i)
366 (*ind_zone)[i] = conv16(sbi->native, src_ptr[i]);
367 } else {
368 uint32_t *src_ptr = b->data;
369
370 for (i = 0; i < sbi->block_size / sizeof(uint32_t); ++i)
371 (*ind_zone)[i] = conv32(sbi->native, src_ptr[i]);
372 }
373
374 return block_put(b);
375}
376
377static errno_t
378write_ind_zone(struct mfs_instance *inst, uint32_t zone, uint32_t *ind_zone)
379{
380 struct mfs_sb_info *sbi = inst->sbi;
381 errno_t r;
382 unsigned i;
383 block_t *b;
384
385 r = block_get(&b, inst->service_id, zone, BLOCK_FLAGS_NOREAD);
386 if (r != EOK)
387 return r;
388
389 if (sbi->fs_version == MFS_VERSION_V1) {
390 uint16_t *dest_ptr = b->data;
391
392 for (i = 0; i < sbi->block_size / sizeof(uint16_t); ++i)
393 dest_ptr[i] = conv16(sbi->native, ind_zone[i]);
394 } else {
395 uint32_t *dest_ptr = b->data;
396
397 for (i = 0; i < sbi->block_size / sizeof(uint32_t); ++i)
398 dest_ptr[i] = conv32(sbi->native, ind_zone[i]);
399
400 }
401 b->dirty = true;
402
403 return block_put(b);
404}
405
406/**
407 * @}
408 */
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