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Commit | Line | Data |
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3407ef52 JB |
1 | /* |
2 | * Copyright (C) 2003 Sistina Software (UK) Limited. | |
a3998799 | 3 | * Copyright (C) 2004, 2010-2011 Red Hat, Inc. All rights reserved. |
3407ef52 JB |
4 | * |
5 | * This file is released under the GPL. | |
6 | */ | |
7 | ||
8 | #include <linux/device-mapper.h> | |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/init.h> | |
12 | #include <linux/blkdev.h> | |
13 | #include <linux/bio.h> | |
14 | #include <linux/slab.h> | |
15 | ||
16 | #define DM_MSG_PREFIX "flakey" | |
17 | ||
a3998799 | 18 | #define all_corrupt_bio_flags_match(bio, fc) \ |
1eff9d32 | 19 | (((bio)->bi_opf & (fc)->corrupt_bio_flags) == (fc)->corrupt_bio_flags) |
a3998799 | 20 | |
3407ef52 JB |
21 | /* |
22 | * Flakey: Used for testing only, simulates intermittent, | |
23 | * catastrophic device failure. | |
24 | */ | |
25 | struct flakey_c { | |
26 | struct dm_dev *dev; | |
27 | unsigned long start_time; | |
28 | sector_t start; | |
29 | unsigned up_interval; | |
30 | unsigned down_interval; | |
b26f5e3d | 31 | unsigned long flags; |
a3998799 MS |
32 | unsigned corrupt_bio_byte; |
33 | unsigned corrupt_bio_rw; | |
34 | unsigned corrupt_bio_value; | |
35 | unsigned corrupt_bio_flags; | |
3407ef52 JB |
36 | }; |
37 | ||
b26f5e3d MS |
38 | enum feature_flag_bits { |
39 | DROP_WRITES | |
40 | }; | |
41 | ||
c7cfdf59 MP |
42 | struct per_bio_data { |
43 | bool bio_submitted; | |
44 | }; | |
45 | ||
b26f5e3d MS |
46 | static int parse_features(struct dm_arg_set *as, struct flakey_c *fc, |
47 | struct dm_target *ti) | |
dfd068b0 MS |
48 | { |
49 | int r; | |
50 | unsigned argc; | |
51 | const char *arg_name; | |
52 | ||
53 | static struct dm_arg _args[] = { | |
a3998799 MS |
54 | {0, 6, "Invalid number of feature args"}, |
55 | {1, UINT_MAX, "Invalid corrupt bio byte"}, | |
56 | {0, 255, "Invalid corrupt value to write into bio byte (0-255)"}, | |
57 | {0, UINT_MAX, "Invalid corrupt bio flags mask"}, | |
dfd068b0 MS |
58 | }; |
59 | ||
60 | /* No feature arguments supplied. */ | |
61 | if (!as->argc) | |
62 | return 0; | |
63 | ||
64 | r = dm_read_arg_group(_args, as, &argc, &ti->error); | |
65 | if (r) | |
a3998799 | 66 | return r; |
dfd068b0 | 67 | |
a3998799 | 68 | while (argc) { |
dfd068b0 MS |
69 | arg_name = dm_shift_arg(as); |
70 | argc--; | |
71 | ||
b26f5e3d MS |
72 | /* |
73 | * drop_writes | |
74 | */ | |
75 | if (!strcasecmp(arg_name, "drop_writes")) { | |
76 | if (test_and_set_bit(DROP_WRITES, &fc->flags)) { | |
77 | ti->error = "Feature drop_writes duplicated"; | |
78 | return -EINVAL; | |
79 | } | |
80 | ||
81 | continue; | |
82 | } | |
83 | ||
a3998799 MS |
84 | /* |
85 | * corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags> | |
86 | */ | |
87 | if (!strcasecmp(arg_name, "corrupt_bio_byte")) { | |
68e58a29 | 88 | if (!argc) { |
a3998799 | 89 | ti->error = "Feature corrupt_bio_byte requires parameters"; |
68e58a29 MS |
90 | return -EINVAL; |
91 | } | |
a3998799 MS |
92 | |
93 | r = dm_read_arg(_args + 1, as, &fc->corrupt_bio_byte, &ti->error); | |
94 | if (r) | |
95 | return r; | |
96 | argc--; | |
97 | ||
98 | /* | |
99 | * Direction r or w? | |
100 | */ | |
101 | arg_name = dm_shift_arg(as); | |
102 | if (!strcasecmp(arg_name, "w")) | |
103 | fc->corrupt_bio_rw = WRITE; | |
104 | else if (!strcasecmp(arg_name, "r")) | |
105 | fc->corrupt_bio_rw = READ; | |
106 | else { | |
107 | ti->error = "Invalid corrupt bio direction (r or w)"; | |
108 | return -EINVAL; | |
109 | } | |
110 | argc--; | |
111 | ||
112 | /* | |
113 | * Value of byte (0-255) to write in place of correct one. | |
114 | */ | |
115 | r = dm_read_arg(_args + 2, as, &fc->corrupt_bio_value, &ti->error); | |
116 | if (r) | |
117 | return r; | |
118 | argc--; | |
119 | ||
120 | /* | |
121 | * Only corrupt bios with these flags set. | |
122 | */ | |
123 | r = dm_read_arg(_args + 3, as, &fc->corrupt_bio_flags, &ti->error); | |
124 | if (r) | |
125 | return r; | |
126 | argc--; | |
127 | ||
128 | continue; | |
129 | } | |
130 | ||
dfd068b0 | 131 | ti->error = "Unrecognised flakey feature requested"; |
a3998799 | 132 | return -EINVAL; |
dfd068b0 MS |
133 | } |
134 | ||
a3998799 MS |
135 | if (test_bit(DROP_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) { |
136 | ti->error = "drop_writes is incompatible with corrupt_bio_byte with the WRITE flag set"; | |
137 | return -EINVAL; | |
138 | } | |
139 | ||
140 | return 0; | |
dfd068b0 MS |
141 | } |
142 | ||
3407ef52 | 143 | /* |
dfd068b0 MS |
144 | * Construct a flakey mapping: |
145 | * <dev_path> <offset> <up interval> <down interval> [<#feature args> [<arg>]*] | |
b26f5e3d MS |
146 | * |
147 | * Feature args: | |
148 | * [drop_writes] | |
a3998799 MS |
149 | * [corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>] |
150 | * | |
151 | * Nth_byte starts from 1 for the first byte. | |
152 | * Direction is r for READ or w for WRITE. | |
153 | * bio_flags is ignored if 0. | |
3407ef52 JB |
154 | */ |
155 | static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
156 | { | |
dfd068b0 MS |
157 | static struct dm_arg _args[] = { |
158 | {0, UINT_MAX, "Invalid up interval"}, | |
159 | {0, UINT_MAX, "Invalid down interval"}, | |
160 | }; | |
161 | ||
162 | int r; | |
3407ef52 | 163 | struct flakey_c *fc; |
dfd068b0 MS |
164 | unsigned long long tmpll; |
165 | struct dm_arg_set as; | |
166 | const char *devname; | |
31998ef1 | 167 | char dummy; |
3407ef52 | 168 | |
dfd068b0 MS |
169 | as.argc = argc; |
170 | as.argv = argv; | |
171 | ||
172 | if (argc < 4) { | |
173 | ti->error = "Invalid argument count"; | |
3407ef52 JB |
174 | return -EINVAL; |
175 | } | |
176 | ||
b26f5e3d | 177 | fc = kzalloc(sizeof(*fc), GFP_KERNEL); |
3407ef52 | 178 | if (!fc) { |
75e3a0f5 | 179 | ti->error = "Cannot allocate context"; |
3407ef52 JB |
180 | return -ENOMEM; |
181 | } | |
182 | fc->start_time = jiffies; | |
183 | ||
dfd068b0 MS |
184 | devname = dm_shift_arg(&as); |
185 | ||
e80d1c80 | 186 | r = -EINVAL; |
31998ef1 | 187 | if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1) { |
dfd068b0 | 188 | ti->error = "Invalid device sector"; |
3407ef52 JB |
189 | goto bad; |
190 | } | |
dfd068b0 | 191 | fc->start = tmpll; |
3407ef52 | 192 | |
dfd068b0 MS |
193 | r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error); |
194 | if (r) | |
3407ef52 | 195 | goto bad; |
3407ef52 | 196 | |
dfd068b0 MS |
197 | r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error); |
198 | if (r) | |
3407ef52 | 199 | goto bad; |
3407ef52 JB |
200 | |
201 | if (!(fc->up_interval + fc->down_interval)) { | |
dfd068b0 | 202 | ti->error = "Total (up + down) interval is zero"; |
3407ef52 JB |
203 | goto bad; |
204 | } | |
205 | ||
206 | if (fc->up_interval + fc->down_interval < fc->up_interval) { | |
dfd068b0 | 207 | ti->error = "Interval overflow"; |
3407ef52 JB |
208 | goto bad; |
209 | } | |
210 | ||
b26f5e3d | 211 | r = parse_features(&as, fc, ti); |
dfd068b0 MS |
212 | if (r) |
213 | goto bad; | |
214 | ||
e80d1c80 VG |
215 | r = dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev); |
216 | if (r) { | |
dfd068b0 | 217 | ti->error = "Device lookup failed"; |
3407ef52 JB |
218 | goto bad; |
219 | } | |
220 | ||
55a62eef AK |
221 | ti->num_flush_bios = 1; |
222 | ti->num_discard_bios = 1; | |
30187e1d | 223 | ti->per_io_data_size = sizeof(struct per_bio_data); |
3407ef52 JB |
224 | ti->private = fc; |
225 | return 0; | |
226 | ||
227 | bad: | |
228 | kfree(fc); | |
e80d1c80 | 229 | return r; |
3407ef52 JB |
230 | } |
231 | ||
232 | static void flakey_dtr(struct dm_target *ti) | |
233 | { | |
234 | struct flakey_c *fc = ti->private; | |
235 | ||
236 | dm_put_device(ti, fc->dev); | |
237 | kfree(fc); | |
238 | } | |
239 | ||
240 | static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector) | |
241 | { | |
242 | struct flakey_c *fc = ti->private; | |
243 | ||
30e4171b | 244 | return fc->start + dm_target_offset(ti, bi_sector); |
3407ef52 JB |
245 | } |
246 | ||
247 | static void flakey_map_bio(struct dm_target *ti, struct bio *bio) | |
248 | { | |
249 | struct flakey_c *fc = ti->private; | |
250 | ||
251 | bio->bi_bdev = fc->dev->bdev; | |
252 | if (bio_sectors(bio)) | |
4f024f37 KO |
253 | bio->bi_iter.bi_sector = |
254 | flakey_map_sector(ti, bio->bi_iter.bi_sector); | |
3407ef52 JB |
255 | } |
256 | ||
a3998799 MS |
257 | static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc) |
258 | { | |
259 | unsigned bio_bytes = bio_cur_bytes(bio); | |
260 | char *data = bio_data(bio); | |
261 | ||
262 | /* | |
263 | * Overwrite the Nth byte of the data returned. | |
264 | */ | |
265 | if (data && bio_bytes >= fc->corrupt_bio_byte) { | |
266 | data[fc->corrupt_bio_byte - 1] = fc->corrupt_bio_value; | |
267 | ||
268 | DMDEBUG("Corrupting data bio=%p by writing %u to byte %u " | |
1eff9d32 | 269 | "(rw=%c bi_opf=%u bi_sector=%llu cur_bytes=%u)\n", |
a3998799 | 270 | bio, fc->corrupt_bio_value, fc->corrupt_bio_byte, |
1eff9d32 | 271 | (bio_data_dir(bio) == WRITE) ? 'w' : 'r', bio->bi_opf, |
4f024f37 | 272 | (unsigned long long)bio->bi_iter.bi_sector, bio_bytes); |
a3998799 MS |
273 | } |
274 | } | |
275 | ||
7de3ee57 | 276 | static int flakey_map(struct dm_target *ti, struct bio *bio) |
3407ef52 JB |
277 | { |
278 | struct flakey_c *fc = ti->private; | |
279 | unsigned elapsed; | |
c7cfdf59 MP |
280 | struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data)); |
281 | pb->bio_submitted = false; | |
3407ef52 JB |
282 | |
283 | /* Are we alive ? */ | |
284 | elapsed = (jiffies - fc->start_time) / HZ; | |
b26f5e3d | 285 | if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) { |
a3998799 MS |
286 | /* |
287 | * Flag this bio as submitted while down. | |
288 | */ | |
c7cfdf59 | 289 | pb->bio_submitted = true; |
a3998799 MS |
290 | |
291 | /* | |
299f6230 MS |
292 | * Error reads if neither corrupt_bio_byte or drop_writes are set. |
293 | * Otherwise, flakey_end_io() will decide if the reads should be modified. | |
a3998799 | 294 | */ |
99f3c90d | 295 | if (bio_data_dir(bio) == READ) { |
299f6230 | 296 | if (!fc->corrupt_bio_byte && !test_bit(DROP_WRITES, &fc->flags)) |
99f3c90d | 297 | return -EIO; |
299f6230 | 298 | goto map_bio; |
99f3c90d | 299 | } |
b26f5e3d MS |
300 | |
301 | /* | |
a3998799 | 302 | * Drop writes? |
b26f5e3d MS |
303 | */ |
304 | if (test_bit(DROP_WRITES, &fc->flags)) { | |
4246a0b6 | 305 | bio_endio(bio); |
a3998799 MS |
306 | return DM_MAPIO_SUBMITTED; |
307 | } | |
308 | ||
309 | /* | |
310 | * Corrupt matching writes. | |
311 | */ | |
312 | if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == WRITE)) { | |
313 | if (all_corrupt_bio_flags_match(bio, fc)) | |
314 | corrupt_bio_data(bio, fc); | |
b26f5e3d MS |
315 | goto map_bio; |
316 | } | |
317 | ||
318 | /* | |
a3998799 | 319 | * By default, error all I/O. |
b26f5e3d | 320 | */ |
3407ef52 | 321 | return -EIO; |
b26f5e3d | 322 | } |
3407ef52 | 323 | |
b26f5e3d | 324 | map_bio: |
3407ef52 JB |
325 | flakey_map_bio(ti, bio); |
326 | ||
327 | return DM_MAPIO_REMAPPED; | |
328 | } | |
329 | ||
7de3ee57 | 330 | static int flakey_end_io(struct dm_target *ti, struct bio *bio, int error) |
a3998799 MS |
331 | { |
332 | struct flakey_c *fc = ti->private; | |
c7cfdf59 | 333 | struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data)); |
a3998799 | 334 | |
99f3c90d | 335 | if (!error && pb->bio_submitted && (bio_data_dir(bio) == READ)) { |
299f6230 MS |
336 | if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == READ) && |
337 | all_corrupt_bio_flags_match(bio, fc)) { | |
338 | /* | |
339 | * Corrupt successful matching READs while in down state. | |
340 | */ | |
99f3c90d | 341 | corrupt_bio_data(bio, fc); |
299f6230 MS |
342 | |
343 | } else if (!test_bit(DROP_WRITES, &fc->flags)) { | |
344 | /* | |
345 | * Error read during the down_interval if drop_writes | |
346 | * wasn't configured. | |
347 | */ | |
99f3c90d | 348 | return -EIO; |
299f6230 | 349 | } |
99f3c90d | 350 | } |
a3998799 MS |
351 | |
352 | return error; | |
353 | } | |
354 | ||
fd7c092e MP |
355 | static void flakey_status(struct dm_target *ti, status_type_t type, |
356 | unsigned status_flags, char *result, unsigned maxlen) | |
3407ef52 | 357 | { |
b26f5e3d | 358 | unsigned sz = 0; |
3407ef52 | 359 | struct flakey_c *fc = ti->private; |
b26f5e3d | 360 | unsigned drop_writes; |
3407ef52 JB |
361 | |
362 | switch (type) { | |
363 | case STATUSTYPE_INFO: | |
364 | result[0] = '\0'; | |
365 | break; | |
366 | ||
367 | case STATUSTYPE_TABLE: | |
b26f5e3d MS |
368 | DMEMIT("%s %llu %u %u ", fc->dev->name, |
369 | (unsigned long long)fc->start, fc->up_interval, | |
370 | fc->down_interval); | |
371 | ||
372 | drop_writes = test_bit(DROP_WRITES, &fc->flags); | |
a3998799 MS |
373 | DMEMIT("%u ", drop_writes + (fc->corrupt_bio_byte > 0) * 5); |
374 | ||
b26f5e3d MS |
375 | if (drop_writes) |
376 | DMEMIT("drop_writes "); | |
a3998799 MS |
377 | |
378 | if (fc->corrupt_bio_byte) | |
379 | DMEMIT("corrupt_bio_byte %u %c %u %u ", | |
380 | fc->corrupt_bio_byte, | |
381 | (fc->corrupt_bio_rw == WRITE) ? 'w' : 'r', | |
382 | fc->corrupt_bio_value, fc->corrupt_bio_flags); | |
383 | ||
3407ef52 JB |
384 | break; |
385 | } | |
3407ef52 JB |
386 | } |
387 | ||
e56f81e0 CH |
388 | static int flakey_prepare_ioctl(struct dm_target *ti, |
389 | struct block_device **bdev, fmode_t *mode) | |
3407ef52 JB |
390 | { |
391 | struct flakey_c *fc = ti->private; | |
e56f81e0 CH |
392 | |
393 | *bdev = fc->dev->bdev; | |
3407ef52 | 394 | |
ec8013be PB |
395 | /* |
396 | * Only pass ioctls through if the device sizes match exactly. | |
397 | */ | |
398 | if (fc->start || | |
e56f81e0 CH |
399 | ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT) |
400 | return 1; | |
401 | return 0; | |
3407ef52 JB |
402 | } |
403 | ||
3407ef52 JB |
404 | static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data) |
405 | { | |
406 | struct flakey_c *fc = ti->private; | |
407 | ||
408 | return fn(ti, fc->dev, fc->start, ti->len, data); | |
409 | } | |
410 | ||
411 | static struct target_type flakey_target = { | |
412 | .name = "flakey", | |
fd7c092e | 413 | .version = {1, 3, 1}, |
3407ef52 JB |
414 | .module = THIS_MODULE, |
415 | .ctr = flakey_ctr, | |
416 | .dtr = flakey_dtr, | |
417 | .map = flakey_map, | |
a3998799 | 418 | .end_io = flakey_end_io, |
3407ef52 | 419 | .status = flakey_status, |
e56f81e0 | 420 | .prepare_ioctl = flakey_prepare_ioctl, |
3407ef52 JB |
421 | .iterate_devices = flakey_iterate_devices, |
422 | }; | |
423 | ||
424 | static int __init dm_flakey_init(void) | |
425 | { | |
426 | int r = dm_register_target(&flakey_target); | |
427 | ||
428 | if (r < 0) | |
429 | DMERR("register failed %d", r); | |
430 | ||
431 | return r; | |
432 | } | |
433 | ||
434 | static void __exit dm_flakey_exit(void) | |
435 | { | |
436 | dm_unregister_target(&flakey_target); | |
437 | } | |
438 | ||
439 | /* Module hooks */ | |
440 | module_init(dm_flakey_init); | |
441 | module_exit(dm_flakey_exit); | |
442 | ||
443 | MODULE_DESCRIPTION(DM_NAME " flakey target"); | |
444 | MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); | |
445 | MODULE_LICENSE("GPL"); |