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e4f3fabd BG |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Copyright (c) 2018 Red Hat, Inc. | |
4 | * | |
5 | * This is a test "dust" device, which fails reads on specified | |
6 | * sectors, emulating the behavior of a hard disk drive sending | |
7 | * a "Read Medium Error" sense. | |
8 | * | |
9 | */ | |
10 | ||
11 | #include <linux/device-mapper.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/rbtree.h> | |
14 | ||
15 | #define DM_MSG_PREFIX "dust" | |
16 | ||
17 | struct badblock { | |
18 | struct rb_node node; | |
19 | sector_t bb; | |
20 | }; | |
21 | ||
22 | struct dust_device { | |
23 | struct dm_dev *dev; | |
24 | struct rb_root badblocklist; | |
25 | unsigned long long badblock_count; | |
26 | spinlock_t dust_lock; | |
27 | unsigned int blksz; | |
28 | unsigned int sect_per_block; | |
29 | sector_t start; | |
30 | bool fail_read_on_bb:1; | |
31 | bool quiet_mode:1; | |
32 | }; | |
33 | ||
34 | static struct badblock *dust_rb_search(struct rb_root *root, sector_t blk) | |
35 | { | |
36 | struct rb_node *node = root->rb_node; | |
37 | ||
38 | while (node) { | |
39 | struct badblock *bblk = rb_entry(node, struct badblock, node); | |
40 | ||
41 | if (bblk->bb > blk) | |
42 | node = node->rb_left; | |
43 | else if (bblk->bb < blk) | |
44 | node = node->rb_right; | |
45 | else | |
46 | return bblk; | |
47 | } | |
48 | ||
49 | return NULL; | |
50 | } | |
51 | ||
52 | static bool dust_rb_insert(struct rb_root *root, struct badblock *new) | |
53 | { | |
54 | struct badblock *bblk; | |
55 | struct rb_node **link = &root->rb_node, *parent = NULL; | |
56 | sector_t value = new->bb; | |
57 | ||
58 | while (*link) { | |
59 | parent = *link; | |
60 | bblk = rb_entry(parent, struct badblock, node); | |
61 | ||
62 | if (bblk->bb > value) | |
63 | link = &(*link)->rb_left; | |
64 | else if (bblk->bb < value) | |
65 | link = &(*link)->rb_right; | |
66 | else | |
67 | return false; | |
68 | } | |
69 | ||
70 | rb_link_node(&new->node, parent, link); | |
71 | rb_insert_color(&new->node, root); | |
72 | ||
73 | return true; | |
74 | } | |
75 | ||
76 | static int dust_remove_block(struct dust_device *dd, unsigned long long block) | |
77 | { | |
78 | struct badblock *bblock; | |
79 | unsigned long flags; | |
80 | ||
81 | spin_lock_irqsave(&dd->dust_lock, flags); | |
82 | bblock = dust_rb_search(&dd->badblocklist, block * dd->sect_per_block); | |
83 | ||
84 | if (bblock == NULL) { | |
85 | if (!dd->quiet_mode) { | |
86 | DMERR("%s: block %llu not found in badblocklist", | |
87 | __func__, block); | |
88 | } | |
89 | spin_unlock_irqrestore(&dd->dust_lock, flags); | |
90 | return -EINVAL; | |
91 | } | |
92 | ||
93 | rb_erase(&bblock->node, &dd->badblocklist); | |
94 | dd->badblock_count--; | |
95 | if (!dd->quiet_mode) | |
96 | DMINFO("%s: badblock removed at block %llu", __func__, block); | |
97 | kfree(bblock); | |
98 | spin_unlock_irqrestore(&dd->dust_lock, flags); | |
99 | ||
100 | return 0; | |
101 | } | |
102 | ||
103 | static int dust_add_block(struct dust_device *dd, unsigned long long block) | |
104 | { | |
105 | struct badblock *bblock; | |
106 | unsigned long flags; | |
107 | ||
108 | bblock = kmalloc(sizeof(*bblock), GFP_KERNEL); | |
109 | if (bblock == NULL) { | |
110 | if (!dd->quiet_mode) | |
111 | DMERR("%s: badblock allocation failed", __func__); | |
112 | return -ENOMEM; | |
113 | } | |
114 | ||
115 | spin_lock_irqsave(&dd->dust_lock, flags); | |
116 | bblock->bb = block * dd->sect_per_block; | |
117 | if (!dust_rb_insert(&dd->badblocklist, bblock)) { | |
118 | if (!dd->quiet_mode) { | |
119 | DMERR("%s: block %llu already in badblocklist", | |
120 | __func__, block); | |
121 | } | |
122 | spin_unlock_irqrestore(&dd->dust_lock, flags); | |
123 | kfree(bblock); | |
124 | return -EINVAL; | |
125 | } | |
126 | ||
127 | dd->badblock_count++; | |
128 | if (!dd->quiet_mode) | |
129 | DMINFO("%s: badblock added at block %llu", __func__, block); | |
130 | spin_unlock_irqrestore(&dd->dust_lock, flags); | |
131 | ||
132 | return 0; | |
133 | } | |
134 | ||
135 | static int dust_query_block(struct dust_device *dd, unsigned long long block) | |
136 | { | |
137 | struct badblock *bblock; | |
138 | unsigned long flags; | |
139 | ||
140 | spin_lock_irqsave(&dd->dust_lock, flags); | |
141 | bblock = dust_rb_search(&dd->badblocklist, block * dd->sect_per_block); | |
142 | if (bblock != NULL) | |
143 | DMINFO("%s: block %llu found in badblocklist", __func__, block); | |
144 | else | |
145 | DMINFO("%s: block %llu not found in badblocklist", __func__, block); | |
146 | spin_unlock_irqrestore(&dd->dust_lock, flags); | |
147 | ||
148 | return 0; | |
149 | } | |
150 | ||
151 | static int __dust_map_read(struct dust_device *dd, sector_t thisblock) | |
152 | { | |
153 | struct badblock *bblk = dust_rb_search(&dd->badblocklist, thisblock); | |
154 | ||
155 | if (bblk) | |
156 | return DM_MAPIO_KILL; | |
157 | ||
158 | return DM_MAPIO_REMAPPED; | |
159 | } | |
160 | ||
161 | static int dust_map_read(struct dust_device *dd, sector_t thisblock, | |
162 | bool fail_read_on_bb) | |
163 | { | |
164 | unsigned long flags; | |
165 | int ret = DM_MAPIO_REMAPPED; | |
166 | ||
167 | if (fail_read_on_bb) { | |
168 | spin_lock_irqsave(&dd->dust_lock, flags); | |
169 | ret = __dust_map_read(dd, thisblock); | |
170 | spin_unlock_irqrestore(&dd->dust_lock, flags); | |
171 | } | |
172 | ||
173 | return ret; | |
174 | } | |
175 | ||
176 | static void __dust_map_write(struct dust_device *dd, sector_t thisblock) | |
177 | { | |
178 | struct badblock *bblk = dust_rb_search(&dd->badblocklist, thisblock); | |
179 | ||
180 | if (bblk) { | |
181 | rb_erase(&bblk->node, &dd->badblocklist); | |
182 | dd->badblock_count--; | |
183 | kfree(bblk); | |
184 | if (!dd->quiet_mode) { | |
185 | sector_div(thisblock, dd->sect_per_block); | |
186 | DMINFO("block %llu removed from badblocklist by write", | |
187 | (unsigned long long)thisblock); | |
188 | } | |
189 | } | |
190 | } | |
191 | ||
192 | static int dust_map_write(struct dust_device *dd, sector_t thisblock, | |
193 | bool fail_read_on_bb) | |
194 | { | |
195 | unsigned long flags; | |
196 | ||
197 | if (fail_read_on_bb) { | |
198 | spin_lock_irqsave(&dd->dust_lock, flags); | |
199 | __dust_map_write(dd, thisblock); | |
200 | spin_unlock_irqrestore(&dd->dust_lock, flags); | |
201 | } | |
202 | ||
203 | return DM_MAPIO_REMAPPED; | |
204 | } | |
205 | ||
206 | static int dust_map(struct dm_target *ti, struct bio *bio) | |
207 | { | |
208 | struct dust_device *dd = ti->private; | |
209 | int ret; | |
210 | ||
211 | bio_set_dev(bio, dd->dev->bdev); | |
212 | bio->bi_iter.bi_sector = dd->start + dm_target_offset(ti, bio->bi_iter.bi_sector); | |
213 | ||
214 | if (bio_data_dir(bio) == READ) | |
215 | ret = dust_map_read(dd, bio->bi_iter.bi_sector, dd->fail_read_on_bb); | |
216 | else | |
217 | ret = dust_map_write(dd, bio->bi_iter.bi_sector, dd->fail_read_on_bb); | |
218 | ||
219 | return ret; | |
220 | } | |
221 | ||
222 | static bool __dust_clear_badblocks(struct rb_root *tree, | |
223 | unsigned long long count) | |
224 | { | |
225 | struct rb_node *node = NULL, *nnode = NULL; | |
226 | ||
227 | nnode = rb_first(tree); | |
228 | if (nnode == NULL) { | |
229 | BUG_ON(count != 0); | |
230 | return false; | |
231 | } | |
232 | ||
233 | while (nnode) { | |
234 | node = nnode; | |
235 | nnode = rb_next(node); | |
236 | rb_erase(node, tree); | |
237 | count--; | |
238 | kfree(node); | |
239 | } | |
240 | BUG_ON(count != 0); | |
241 | BUG_ON(tree->rb_node != NULL); | |
242 | ||
243 | return true; | |
244 | } | |
245 | ||
246 | static int dust_clear_badblocks(struct dust_device *dd) | |
247 | { | |
248 | unsigned long flags; | |
249 | struct rb_root badblocklist; | |
250 | unsigned long long badblock_count; | |
251 | ||
252 | spin_lock_irqsave(&dd->dust_lock, flags); | |
253 | badblocklist = dd->badblocklist; | |
254 | badblock_count = dd->badblock_count; | |
255 | dd->badblocklist = RB_ROOT; | |
256 | dd->badblock_count = 0; | |
257 | spin_unlock_irqrestore(&dd->dust_lock, flags); | |
258 | ||
259 | if (!__dust_clear_badblocks(&badblocklist, badblock_count)) | |
260 | DMINFO("%s: no badblocks found", __func__); | |
261 | else | |
262 | DMINFO("%s: badblocks cleared", __func__); | |
263 | ||
264 | return 0; | |
265 | } | |
266 | ||
267 | /* | |
268 | * Target parameters: | |
269 | * | |
270 | * <device_path> <offset> <blksz> | |
271 | * | |
272 | * device_path: path to the block device | |
273 | * offset: offset to data area from start of device_path | |
274 | * blksz: block size (minimum 512, maximum 1073741824, must be a power of 2) | |
275 | */ | |
276 | static int dust_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
277 | { | |
278 | struct dust_device *dd; | |
279 | unsigned long long tmp; | |
280 | char dummy; | |
281 | unsigned int blksz; | |
282 | unsigned int sect_per_block; | |
283 | sector_t DUST_MAX_BLKSZ_SECTORS = 2097152; | |
284 | sector_t max_block_sectors = min(ti->len, DUST_MAX_BLKSZ_SECTORS); | |
285 | ||
286 | if (argc != 3) { | |
287 | ti->error = "Invalid argument count"; | |
288 | return -EINVAL; | |
289 | } | |
290 | ||
291 | if (kstrtouint(argv[2], 10, &blksz) || !blksz) { | |
292 | ti->error = "Invalid block size parameter"; | |
293 | return -EINVAL; | |
294 | } | |
295 | ||
296 | if (blksz < 512) { | |
297 | ti->error = "Block size must be at least 512"; | |
298 | return -EINVAL; | |
299 | } | |
300 | ||
301 | if (!is_power_of_2(blksz)) { | |
302 | ti->error = "Block size must be a power of 2"; | |
303 | return -EINVAL; | |
304 | } | |
305 | ||
306 | if (to_sector(blksz) > max_block_sectors) { | |
307 | ti->error = "Block size is too large"; | |
308 | return -EINVAL; | |
309 | } | |
310 | ||
311 | sect_per_block = (blksz >> SECTOR_SHIFT); | |
312 | ||
313 | if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1 || tmp != (sector_t)tmp) { | |
314 | ti->error = "Invalid device offset sector"; | |
315 | return -EINVAL; | |
316 | } | |
317 | ||
318 | dd = kzalloc(sizeof(struct dust_device), GFP_KERNEL); | |
319 | if (dd == NULL) { | |
320 | ti->error = "Cannot allocate context"; | |
321 | return -ENOMEM; | |
322 | } | |
323 | ||
324 | if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dd->dev)) { | |
325 | ti->error = "Device lookup failed"; | |
326 | kfree(dd); | |
327 | return -EINVAL; | |
328 | } | |
329 | ||
330 | dd->sect_per_block = sect_per_block; | |
331 | dd->blksz = blksz; | |
332 | dd->start = tmp; | |
333 | ||
334 | /* | |
335 | * Whether to fail a read on a "bad" block. | |
336 | * Defaults to false; enabled later by message. | |
337 | */ | |
338 | dd->fail_read_on_bb = false; | |
339 | ||
340 | /* | |
341 | * Initialize bad block list rbtree. | |
342 | */ | |
343 | dd->badblocklist = RB_ROOT; | |
344 | dd->badblock_count = 0; | |
345 | spin_lock_init(&dd->dust_lock); | |
346 | ||
347 | dd->quiet_mode = false; | |
348 | ||
349 | BUG_ON(dm_set_target_max_io_len(ti, dd->sect_per_block) != 0); | |
350 | ||
351 | ti->num_discard_bios = 1; | |
352 | ti->num_flush_bios = 1; | |
353 | ti->private = dd; | |
354 | ||
355 | return 0; | |
356 | } | |
357 | ||
358 | static void dust_dtr(struct dm_target *ti) | |
359 | { | |
360 | struct dust_device *dd = ti->private; | |
361 | ||
362 | __dust_clear_badblocks(&dd->badblocklist, dd->badblock_count); | |
363 | dm_put_device(ti, dd->dev); | |
364 | kfree(dd); | |
365 | } | |
366 | ||
367 | static int dust_message(struct dm_target *ti, unsigned int argc, char **argv, | |
368 | char *result_buf, unsigned int maxlen) | |
369 | { | |
370 | struct dust_device *dd = ti->private; | |
371 | sector_t size = i_size_read(dd->dev->bdev->bd_inode) >> SECTOR_SHIFT; | |
372 | bool invalid_msg = false; | |
373 | int result = -EINVAL; | |
374 | unsigned long long tmp, block; | |
375 | unsigned long flags; | |
376 | char dummy; | |
377 | ||
378 | if (argc == 1) { | |
379 | if (!strcasecmp(argv[0], "addbadblock") || | |
380 | !strcasecmp(argv[0], "removebadblock") || | |
381 | !strcasecmp(argv[0], "queryblock")) { | |
382 | DMERR("%s requires an additional argument", argv[0]); | |
383 | } else if (!strcasecmp(argv[0], "disable")) { | |
384 | DMINFO("disabling read failures on bad sectors"); | |
385 | dd->fail_read_on_bb = false; | |
386 | result = 0; | |
387 | } else if (!strcasecmp(argv[0], "enable")) { | |
388 | DMINFO("enabling read failures on bad sectors"); | |
389 | dd->fail_read_on_bb = true; | |
390 | result = 0; | |
391 | } else if (!strcasecmp(argv[0], "countbadblocks")) { | |
392 | spin_lock_irqsave(&dd->dust_lock, flags); | |
393 | DMINFO("countbadblocks: %llu badblock(s) found", | |
394 | dd->badblock_count); | |
395 | spin_unlock_irqrestore(&dd->dust_lock, flags); | |
396 | result = 0; | |
397 | } else if (!strcasecmp(argv[0], "clearbadblocks")) { | |
398 | result = dust_clear_badblocks(dd); | |
399 | } else if (!strcasecmp(argv[0], "quiet")) { | |
400 | if (!dd->quiet_mode) | |
401 | dd->quiet_mode = true; | |
402 | else | |
403 | dd->quiet_mode = false; | |
404 | result = 0; | |
405 | } else { | |
406 | invalid_msg = true; | |
407 | } | |
408 | } else if (argc == 2) { | |
409 | if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1) | |
410 | return result; | |
411 | ||
412 | block = tmp; | |
413 | sector_div(size, dd->sect_per_block); | |
cacddeab | 414 | if (block > size) { |
e4f3fabd BG |
415 | DMERR("selected block value out of range"); |
416 | return result; | |
417 | } | |
418 | ||
419 | if (!strcasecmp(argv[0], "addbadblock")) | |
420 | result = dust_add_block(dd, block); | |
421 | else if (!strcasecmp(argv[0], "removebadblock")) | |
422 | result = dust_remove_block(dd, block); | |
423 | else if (!strcasecmp(argv[0], "queryblock")) | |
424 | result = dust_query_block(dd, block); | |
425 | else | |
426 | invalid_msg = true; | |
427 | ||
428 | } else | |
429 | DMERR("invalid number of arguments '%d'", argc); | |
430 | ||
431 | if (invalid_msg) | |
432 | DMERR("unrecognized message '%s' received", argv[0]); | |
433 | ||
434 | return result; | |
435 | } | |
436 | ||
437 | static void dust_status(struct dm_target *ti, status_type_t type, | |
438 | unsigned int status_flags, char *result, unsigned int maxlen) | |
439 | { | |
440 | struct dust_device *dd = ti->private; | |
441 | unsigned int sz = 0; | |
442 | ||
443 | switch (type) { | |
444 | case STATUSTYPE_INFO: | |
445 | DMEMIT("%s %s %s", dd->dev->name, | |
446 | dd->fail_read_on_bb ? "fail_read_on_bad_block" : "bypass", | |
447 | dd->quiet_mode ? "quiet" : "verbose"); | |
448 | break; | |
449 | ||
450 | case STATUSTYPE_TABLE: | |
451 | DMEMIT("%s %llu %u", dd->dev->name, | |
452 | (unsigned long long)dd->start, dd->blksz); | |
453 | break; | |
454 | } | |
455 | } | |
456 | ||
457 | static int dust_prepare_ioctl(struct dm_target *ti, struct block_device **bdev) | |
458 | { | |
459 | struct dust_device *dd = ti->private; | |
460 | struct dm_dev *dev = dd->dev; | |
461 | ||
462 | *bdev = dev->bdev; | |
463 | ||
464 | /* | |
465 | * Only pass ioctls through if the device sizes match exactly. | |
466 | */ | |
467 | if (dd->start || | |
468 | ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT) | |
469 | return 1; | |
470 | ||
471 | return 0; | |
472 | } | |
473 | ||
474 | static int dust_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, | |
475 | void *data) | |
476 | { | |
477 | struct dust_device *dd = ti->private; | |
478 | ||
479 | return fn(ti, dd->dev, dd->start, ti->len, data); | |
480 | } | |
481 | ||
482 | static struct target_type dust_target = { | |
483 | .name = "dust", | |
484 | .version = {1, 0, 0}, | |
485 | .module = THIS_MODULE, | |
486 | .ctr = dust_ctr, | |
487 | .dtr = dust_dtr, | |
488 | .iterate_devices = dust_iterate_devices, | |
489 | .map = dust_map, | |
490 | .message = dust_message, | |
491 | .status = dust_status, | |
492 | .prepare_ioctl = dust_prepare_ioctl, | |
493 | }; | |
494 | ||
9ccce5a0 | 495 | static int __init dm_dust_init(void) |
e4f3fabd BG |
496 | { |
497 | int result = dm_register_target(&dust_target); | |
498 | ||
499 | if (result < 0) | |
500 | DMERR("dm_register_target failed %d", result); | |
501 | ||
502 | return result; | |
503 | } | |
504 | ||
9ccce5a0 | 505 | static void __exit dm_dust_exit(void) |
e4f3fabd BG |
506 | { |
507 | dm_unregister_target(&dust_target); | |
508 | } | |
509 | ||
510 | module_init(dm_dust_init); | |
511 | module_exit(dm_dust_exit); | |
512 | ||
513 | MODULE_DESCRIPTION(DM_NAME " dust test target"); | |
514 | MODULE_AUTHOR("Bryan Gurney <dm-devel@redhat.com>"); | |
515 | MODULE_LICENSE("GPL"); |