Commit | Line | Data |
---|---|---|
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 MS |
18 | #define all_corrupt_bio_flags_match(bio, fc) \ |
19 | (((bio)->bi_rw & (fc)->corrupt_bio_flags) == (fc)->corrupt_bio_flags) | |
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 | ||
31998ef1 | 186 | if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1) { |
dfd068b0 | 187 | ti->error = "Invalid device sector"; |
3407ef52 JB |
188 | goto bad; |
189 | } | |
dfd068b0 | 190 | fc->start = tmpll; |
3407ef52 | 191 | |
dfd068b0 MS |
192 | r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error); |
193 | if (r) | |
3407ef52 | 194 | goto bad; |
3407ef52 | 195 | |
dfd068b0 MS |
196 | r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error); |
197 | if (r) | |
3407ef52 | 198 | goto bad; |
3407ef52 JB |
199 | |
200 | if (!(fc->up_interval + fc->down_interval)) { | |
dfd068b0 | 201 | ti->error = "Total (up + down) interval is zero"; |
3407ef52 JB |
202 | goto bad; |
203 | } | |
204 | ||
205 | if (fc->up_interval + fc->down_interval < fc->up_interval) { | |
dfd068b0 | 206 | ti->error = "Interval overflow"; |
3407ef52 JB |
207 | goto bad; |
208 | } | |
209 | ||
b26f5e3d | 210 | r = parse_features(&as, fc, ti); |
dfd068b0 MS |
211 | if (r) |
212 | goto bad; | |
213 | ||
214 | if (dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev)) { | |
215 | ti->error = "Device lookup failed"; | |
3407ef52 JB |
216 | goto bad; |
217 | } | |
218 | ||
55a62eef AK |
219 | ti->num_flush_bios = 1; |
220 | ti->num_discard_bios = 1; | |
c7cfdf59 | 221 | ti->per_bio_data_size = sizeof(struct per_bio_data); |
3407ef52 JB |
222 | ti->private = fc; |
223 | return 0; | |
224 | ||
225 | bad: | |
226 | kfree(fc); | |
227 | return -EINVAL; | |
228 | } | |
229 | ||
230 | static void flakey_dtr(struct dm_target *ti) | |
231 | { | |
232 | struct flakey_c *fc = ti->private; | |
233 | ||
234 | dm_put_device(ti, fc->dev); | |
235 | kfree(fc); | |
236 | } | |
237 | ||
238 | static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector) | |
239 | { | |
240 | struct flakey_c *fc = ti->private; | |
241 | ||
30e4171b | 242 | return fc->start + dm_target_offset(ti, bi_sector); |
3407ef52 JB |
243 | } |
244 | ||
245 | static void flakey_map_bio(struct dm_target *ti, struct bio *bio) | |
246 | { | |
247 | struct flakey_c *fc = ti->private; | |
248 | ||
249 | bio->bi_bdev = fc->dev->bdev; | |
250 | if (bio_sectors(bio)) | |
251 | bio->bi_sector = flakey_map_sector(ti, bio->bi_sector); | |
252 | } | |
253 | ||
a3998799 MS |
254 | static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc) |
255 | { | |
256 | unsigned bio_bytes = bio_cur_bytes(bio); | |
257 | char *data = bio_data(bio); | |
258 | ||
259 | /* | |
260 | * Overwrite the Nth byte of the data returned. | |
261 | */ | |
262 | if (data && bio_bytes >= fc->corrupt_bio_byte) { | |
263 | data[fc->corrupt_bio_byte - 1] = fc->corrupt_bio_value; | |
264 | ||
265 | DMDEBUG("Corrupting data bio=%p by writing %u to byte %u " | |
266 | "(rw=%c bi_rw=%lu bi_sector=%llu cur_bytes=%u)\n", | |
267 | bio, fc->corrupt_bio_value, fc->corrupt_bio_byte, | |
268 | (bio_data_dir(bio) == WRITE) ? 'w' : 'r', | |
269 | bio->bi_rw, (unsigned long long)bio->bi_sector, bio_bytes); | |
270 | } | |
271 | } | |
272 | ||
7de3ee57 | 273 | static int flakey_map(struct dm_target *ti, struct bio *bio) |
3407ef52 JB |
274 | { |
275 | struct flakey_c *fc = ti->private; | |
276 | unsigned elapsed; | |
c7cfdf59 MP |
277 | struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data)); |
278 | pb->bio_submitted = false; | |
3407ef52 JB |
279 | |
280 | /* Are we alive ? */ | |
281 | elapsed = (jiffies - fc->start_time) / HZ; | |
b26f5e3d | 282 | if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) { |
a3998799 MS |
283 | /* |
284 | * Flag this bio as submitted while down. | |
285 | */ | |
c7cfdf59 | 286 | pb->bio_submitted = true; |
a3998799 MS |
287 | |
288 | /* | |
289 | * Map reads as normal. | |
290 | */ | |
291 | if (bio_data_dir(bio) == READ) | |
292 | goto map_bio; | |
b26f5e3d MS |
293 | |
294 | /* | |
a3998799 | 295 | * Drop writes? |
b26f5e3d MS |
296 | */ |
297 | if (test_bit(DROP_WRITES, &fc->flags)) { | |
a3998799 MS |
298 | bio_endio(bio, 0); |
299 | return DM_MAPIO_SUBMITTED; | |
300 | } | |
301 | ||
302 | /* | |
303 | * Corrupt matching writes. | |
304 | */ | |
305 | if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == WRITE)) { | |
306 | if (all_corrupt_bio_flags_match(bio, fc)) | |
307 | corrupt_bio_data(bio, fc); | |
b26f5e3d MS |
308 | goto map_bio; |
309 | } | |
310 | ||
311 | /* | |
a3998799 | 312 | * By default, error all I/O. |
b26f5e3d | 313 | */ |
3407ef52 | 314 | return -EIO; |
b26f5e3d | 315 | } |
3407ef52 | 316 | |
b26f5e3d | 317 | map_bio: |
3407ef52 JB |
318 | flakey_map_bio(ti, bio); |
319 | ||
320 | return DM_MAPIO_REMAPPED; | |
321 | } | |
322 | ||
7de3ee57 | 323 | static int flakey_end_io(struct dm_target *ti, struct bio *bio, int error) |
a3998799 MS |
324 | { |
325 | struct flakey_c *fc = ti->private; | |
c7cfdf59 | 326 | struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data)); |
a3998799 MS |
327 | |
328 | /* | |
329 | * Corrupt successful READs while in down state. | |
330 | * If flags were specified, only corrupt those that match. | |
331 | */ | |
c7cfdf59 | 332 | if (fc->corrupt_bio_byte && !error && pb->bio_submitted && |
a3998799 MS |
333 | (bio_data_dir(bio) == READ) && (fc->corrupt_bio_rw == READ) && |
334 | all_corrupt_bio_flags_match(bio, fc)) | |
335 | corrupt_bio_data(bio, fc); | |
336 | ||
337 | return error; | |
338 | } | |
339 | ||
fd7c092e MP |
340 | static void flakey_status(struct dm_target *ti, status_type_t type, |
341 | unsigned status_flags, char *result, unsigned maxlen) | |
3407ef52 | 342 | { |
b26f5e3d | 343 | unsigned sz = 0; |
3407ef52 | 344 | struct flakey_c *fc = ti->private; |
b26f5e3d | 345 | unsigned drop_writes; |
3407ef52 JB |
346 | |
347 | switch (type) { | |
348 | case STATUSTYPE_INFO: | |
349 | result[0] = '\0'; | |
350 | break; | |
351 | ||
352 | case STATUSTYPE_TABLE: | |
b26f5e3d MS |
353 | DMEMIT("%s %llu %u %u ", fc->dev->name, |
354 | (unsigned long long)fc->start, fc->up_interval, | |
355 | fc->down_interval); | |
356 | ||
357 | drop_writes = test_bit(DROP_WRITES, &fc->flags); | |
a3998799 MS |
358 | DMEMIT("%u ", drop_writes + (fc->corrupt_bio_byte > 0) * 5); |
359 | ||
b26f5e3d MS |
360 | if (drop_writes) |
361 | DMEMIT("drop_writes "); | |
a3998799 MS |
362 | |
363 | if (fc->corrupt_bio_byte) | |
364 | DMEMIT("corrupt_bio_byte %u %c %u %u ", | |
365 | fc->corrupt_bio_byte, | |
366 | (fc->corrupt_bio_rw == WRITE) ? 'w' : 'r', | |
367 | fc->corrupt_bio_value, fc->corrupt_bio_flags); | |
368 | ||
3407ef52 JB |
369 | break; |
370 | } | |
3407ef52 JB |
371 | } |
372 | ||
373 | static int flakey_ioctl(struct dm_target *ti, unsigned int cmd, unsigned long arg) | |
374 | { | |
375 | struct flakey_c *fc = ti->private; | |
ec8013be PB |
376 | struct dm_dev *dev = fc->dev; |
377 | int r = 0; | |
3407ef52 | 378 | |
ec8013be PB |
379 | /* |
380 | * Only pass ioctls through if the device sizes match exactly. | |
381 | */ | |
382 | if (fc->start || | |
383 | ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT) | |
384 | r = scsi_verify_blk_ioctl(NULL, cmd); | |
385 | ||
386 | return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg); | |
3407ef52 JB |
387 | } |
388 | ||
389 | static int flakey_merge(struct dm_target *ti, struct bvec_merge_data *bvm, | |
390 | struct bio_vec *biovec, int max_size) | |
391 | { | |
392 | struct flakey_c *fc = ti->private; | |
393 | struct request_queue *q = bdev_get_queue(fc->dev->bdev); | |
394 | ||
395 | if (!q->merge_bvec_fn) | |
396 | return max_size; | |
397 | ||
398 | bvm->bi_bdev = fc->dev->bdev; | |
399 | bvm->bi_sector = flakey_map_sector(ti, bvm->bi_sector); | |
400 | ||
401 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | |
402 | } | |
403 | ||
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 JB |
419 | .status = flakey_status, |
420 | .ioctl = flakey_ioctl, | |
421 | .merge = flakey_merge, | |
422 | .iterate_devices = flakey_iterate_devices, | |
423 | }; | |
424 | ||
425 | static int __init dm_flakey_init(void) | |
426 | { | |
427 | int r = dm_register_target(&flakey_target); | |
428 | ||
429 | if (r < 0) | |
430 | DMERR("register failed %d", r); | |
431 | ||
432 | return r; | |
433 | } | |
434 | ||
435 | static void __exit dm_flakey_exit(void) | |
436 | { | |
437 | dm_unregister_target(&flakey_target); | |
438 | } | |
439 | ||
440 | /* Module hooks */ | |
441 | module_init(dm_flakey_init); | |
442 | module_exit(dm_flakey_exit); | |
443 | ||
444 | MODULE_DESCRIPTION(DM_NAME " flakey target"); | |
445 | MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); | |
446 | MODULE_LICENSE("GPL"); |