Loading...
1/*
2 * Copyright (C) 2003 Sistina Software (UK) Limited.
3 * Copyright (C) 2004, 2010-2011 Red Hat, Inc. All rights reserved.
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
18#define all_corrupt_bio_flags_match(bio, fc) \
19 (((bio)->bi_opf & (fc)->corrupt_bio_flags) == (fc)->corrupt_bio_flags)
20
21/*
22 * Flakey: Used for testing only, simulates intermittent,
23 * catastrophic device failure.
24 */
25struct flakey_c {
26 struct dm_dev *dev;
27 unsigned long start_time;
28 sector_t start;
29 unsigned up_interval;
30 unsigned down_interval;
31 unsigned long flags;
32 unsigned corrupt_bio_byte;
33 unsigned corrupt_bio_rw;
34 unsigned corrupt_bio_value;
35 blk_opf_t corrupt_bio_flags;
36};
37
38enum feature_flag_bits {
39 DROP_WRITES,
40 ERROR_WRITES
41};
42
43struct per_bio_data {
44 bool bio_submitted;
45};
46
47static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
48 struct dm_target *ti)
49{
50 int r;
51 unsigned argc;
52 const char *arg_name;
53
54 static const struct dm_arg _args[] = {
55 {0, 6, "Invalid number of feature args"},
56 {1, UINT_MAX, "Invalid corrupt bio byte"},
57 {0, 255, "Invalid corrupt value to write into bio byte (0-255)"},
58 {0, UINT_MAX, "Invalid corrupt bio flags mask"},
59 };
60
61 /* No feature arguments supplied. */
62 if (!as->argc)
63 return 0;
64
65 r = dm_read_arg_group(_args, as, &argc, &ti->error);
66 if (r)
67 return r;
68
69 while (argc) {
70 arg_name = dm_shift_arg(as);
71 argc--;
72
73 if (!arg_name) {
74 ti->error = "Insufficient feature arguments";
75 return -EINVAL;
76 }
77
78 /*
79 * drop_writes
80 */
81 if (!strcasecmp(arg_name, "drop_writes")) {
82 if (test_and_set_bit(DROP_WRITES, &fc->flags)) {
83 ti->error = "Feature drop_writes duplicated";
84 return -EINVAL;
85 } else if (test_bit(ERROR_WRITES, &fc->flags)) {
86 ti->error = "Feature drop_writes conflicts with feature error_writes";
87 return -EINVAL;
88 }
89
90 continue;
91 }
92
93 /*
94 * error_writes
95 */
96 if (!strcasecmp(arg_name, "error_writes")) {
97 if (test_and_set_bit(ERROR_WRITES, &fc->flags)) {
98 ti->error = "Feature error_writes duplicated";
99 return -EINVAL;
100
101 } else if (test_bit(DROP_WRITES, &fc->flags)) {
102 ti->error = "Feature error_writes conflicts with feature drop_writes";
103 return -EINVAL;
104 }
105
106 continue;
107 }
108
109 /*
110 * corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>
111 */
112 if (!strcasecmp(arg_name, "corrupt_bio_byte")) {
113 if (!argc) {
114 ti->error = "Feature corrupt_bio_byte requires parameters";
115 return -EINVAL;
116 }
117
118 r = dm_read_arg(_args + 1, as, &fc->corrupt_bio_byte, &ti->error);
119 if (r)
120 return r;
121 argc--;
122
123 /*
124 * Direction r or w?
125 */
126 arg_name = dm_shift_arg(as);
127 if (!strcasecmp(arg_name, "w"))
128 fc->corrupt_bio_rw = WRITE;
129 else if (!strcasecmp(arg_name, "r"))
130 fc->corrupt_bio_rw = READ;
131 else {
132 ti->error = "Invalid corrupt bio direction (r or w)";
133 return -EINVAL;
134 }
135 argc--;
136
137 /*
138 * Value of byte (0-255) to write in place of correct one.
139 */
140 r = dm_read_arg(_args + 2, as, &fc->corrupt_bio_value, &ti->error);
141 if (r)
142 return r;
143 argc--;
144
145 /*
146 * Only corrupt bios with these flags set.
147 */
148 BUILD_BUG_ON(sizeof(fc->corrupt_bio_flags) !=
149 sizeof(unsigned int));
150 r = dm_read_arg(_args + 3, as,
151 (__force unsigned *)&fc->corrupt_bio_flags,
152 &ti->error);
153 if (r)
154 return r;
155 argc--;
156
157 continue;
158 }
159
160 ti->error = "Unrecognised flakey feature requested";
161 return -EINVAL;
162 }
163
164 if (test_bit(DROP_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) {
165 ti->error = "drop_writes is incompatible with corrupt_bio_byte with the WRITE flag set";
166 return -EINVAL;
167
168 } else if (test_bit(ERROR_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) {
169 ti->error = "error_writes is incompatible with corrupt_bio_byte with the WRITE flag set";
170 return -EINVAL;
171 }
172
173 return 0;
174}
175
176/*
177 * Construct a flakey mapping:
178 * <dev_path> <offset> <up interval> <down interval> [<#feature args> [<arg>]*]
179 *
180 * Feature args:
181 * [drop_writes]
182 * [corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>]
183 *
184 * Nth_byte starts from 1 for the first byte.
185 * Direction is r for READ or w for WRITE.
186 * bio_flags is ignored if 0.
187 */
188static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv)
189{
190 static const struct dm_arg _args[] = {
191 {0, UINT_MAX, "Invalid up interval"},
192 {0, UINT_MAX, "Invalid down interval"},
193 };
194
195 int r;
196 struct flakey_c *fc;
197 unsigned long long tmpll;
198 struct dm_arg_set as;
199 const char *devname;
200 char dummy;
201
202 as.argc = argc;
203 as.argv = argv;
204
205 if (argc < 4) {
206 ti->error = "Invalid argument count";
207 return -EINVAL;
208 }
209
210 fc = kzalloc(sizeof(*fc), GFP_KERNEL);
211 if (!fc) {
212 ti->error = "Cannot allocate context";
213 return -ENOMEM;
214 }
215 fc->start_time = jiffies;
216
217 devname = dm_shift_arg(&as);
218
219 r = -EINVAL;
220 if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1 || tmpll != (sector_t)tmpll) {
221 ti->error = "Invalid device sector";
222 goto bad;
223 }
224 fc->start = tmpll;
225
226 r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
227 if (r)
228 goto bad;
229
230 r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
231 if (r)
232 goto bad;
233
234 if (!(fc->up_interval + fc->down_interval)) {
235 ti->error = "Total (up + down) interval is zero";
236 r = -EINVAL;
237 goto bad;
238 }
239
240 if (fc->up_interval + fc->down_interval < fc->up_interval) {
241 ti->error = "Interval overflow";
242 r = -EINVAL;
243 goto bad;
244 }
245
246 r = parse_features(&as, fc, ti);
247 if (r)
248 goto bad;
249
250 r = dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev);
251 if (r) {
252 ti->error = "Device lookup failed";
253 goto bad;
254 }
255
256 ti->num_flush_bios = 1;
257 ti->num_discard_bios = 1;
258 ti->per_io_data_size = sizeof(struct per_bio_data);
259 ti->private = fc;
260 return 0;
261
262bad:
263 kfree(fc);
264 return r;
265}
266
267static void flakey_dtr(struct dm_target *ti)
268{
269 struct flakey_c *fc = ti->private;
270
271 dm_put_device(ti, fc->dev);
272 kfree(fc);
273}
274
275static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector)
276{
277 struct flakey_c *fc = ti->private;
278
279 return fc->start + dm_target_offset(ti, bi_sector);
280}
281
282static void flakey_map_bio(struct dm_target *ti, struct bio *bio)
283{
284 struct flakey_c *fc = ti->private;
285
286 bio_set_dev(bio, fc->dev->bdev);
287 bio->bi_iter.bi_sector = flakey_map_sector(ti, bio->bi_iter.bi_sector);
288}
289
290static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc)
291{
292 unsigned int corrupt_bio_byte = fc->corrupt_bio_byte - 1;
293
294 struct bvec_iter iter;
295 struct bio_vec bvec;
296
297 if (!bio_has_data(bio))
298 return;
299
300 /*
301 * Overwrite the Nth byte of the bio's data, on whichever page
302 * it falls.
303 */
304 bio_for_each_segment(bvec, bio, iter) {
305 if (bio_iter_len(bio, iter) > corrupt_bio_byte) {
306 char *segment = (page_address(bio_iter_page(bio, iter))
307 + bio_iter_offset(bio, iter));
308 segment[corrupt_bio_byte] = fc->corrupt_bio_value;
309 DMDEBUG("Corrupting data bio=%p by writing %u to byte %u "
310 "(rw=%c bi_opf=%u bi_sector=%llu size=%u)\n",
311 bio, fc->corrupt_bio_value, fc->corrupt_bio_byte,
312 (bio_data_dir(bio) == WRITE) ? 'w' : 'r', bio->bi_opf,
313 (unsigned long long)bio->bi_iter.bi_sector, bio->bi_iter.bi_size);
314 break;
315 }
316 corrupt_bio_byte -= bio_iter_len(bio, iter);
317 }
318}
319
320static int flakey_map(struct dm_target *ti, struct bio *bio)
321{
322 struct flakey_c *fc = ti->private;
323 unsigned elapsed;
324 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
325 pb->bio_submitted = false;
326
327 if (op_is_zone_mgmt(bio_op(bio)))
328 goto map_bio;
329
330 /* Are we alive ? */
331 elapsed = (jiffies - fc->start_time) / HZ;
332 if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
333 /*
334 * Flag this bio as submitted while down.
335 */
336 pb->bio_submitted = true;
337
338 /*
339 * Error reads if neither corrupt_bio_byte or drop_writes or error_writes are set.
340 * Otherwise, flakey_end_io() will decide if the reads should be modified.
341 */
342 if (bio_data_dir(bio) == READ) {
343 if (!fc->corrupt_bio_byte && !test_bit(DROP_WRITES, &fc->flags) &&
344 !test_bit(ERROR_WRITES, &fc->flags))
345 return DM_MAPIO_KILL;
346 goto map_bio;
347 }
348
349 /*
350 * Drop or error writes?
351 */
352 if (test_bit(DROP_WRITES, &fc->flags)) {
353 bio_endio(bio);
354 return DM_MAPIO_SUBMITTED;
355 }
356 else if (test_bit(ERROR_WRITES, &fc->flags)) {
357 bio_io_error(bio);
358 return DM_MAPIO_SUBMITTED;
359 }
360
361 /*
362 * Corrupt matching writes.
363 */
364 if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == WRITE)) {
365 if (all_corrupt_bio_flags_match(bio, fc))
366 corrupt_bio_data(bio, fc);
367 goto map_bio;
368 }
369
370 /*
371 * By default, error all I/O.
372 */
373 return DM_MAPIO_KILL;
374 }
375
376map_bio:
377 flakey_map_bio(ti, bio);
378
379 return DM_MAPIO_REMAPPED;
380}
381
382static int flakey_end_io(struct dm_target *ti, struct bio *bio,
383 blk_status_t *error)
384{
385 struct flakey_c *fc = ti->private;
386 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
387
388 if (op_is_zone_mgmt(bio_op(bio)))
389 return DM_ENDIO_DONE;
390
391 if (!*error && pb->bio_submitted && (bio_data_dir(bio) == READ)) {
392 if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == READ) &&
393 all_corrupt_bio_flags_match(bio, fc)) {
394 /*
395 * Corrupt successful matching READs while in down state.
396 */
397 corrupt_bio_data(bio, fc);
398
399 } else if (!test_bit(DROP_WRITES, &fc->flags) &&
400 !test_bit(ERROR_WRITES, &fc->flags)) {
401 /*
402 * Error read during the down_interval if drop_writes
403 * and error_writes were not configured.
404 */
405 *error = BLK_STS_IOERR;
406 }
407 }
408
409 return DM_ENDIO_DONE;
410}
411
412static void flakey_status(struct dm_target *ti, status_type_t type,
413 unsigned status_flags, char *result, unsigned maxlen)
414{
415 unsigned sz = 0;
416 struct flakey_c *fc = ti->private;
417 unsigned drop_writes, error_writes;
418
419 switch (type) {
420 case STATUSTYPE_INFO:
421 result[0] = '\0';
422 break;
423
424 case STATUSTYPE_TABLE:
425 DMEMIT("%s %llu %u %u ", fc->dev->name,
426 (unsigned long long)fc->start, fc->up_interval,
427 fc->down_interval);
428
429 drop_writes = test_bit(DROP_WRITES, &fc->flags);
430 error_writes = test_bit(ERROR_WRITES, &fc->flags);
431 DMEMIT("%u ", drop_writes + error_writes + (fc->corrupt_bio_byte > 0) * 5);
432
433 if (drop_writes)
434 DMEMIT("drop_writes ");
435 else if (error_writes)
436 DMEMIT("error_writes ");
437
438 if (fc->corrupt_bio_byte)
439 DMEMIT("corrupt_bio_byte %u %c %u %u ",
440 fc->corrupt_bio_byte,
441 (fc->corrupt_bio_rw == WRITE) ? 'w' : 'r',
442 fc->corrupt_bio_value, fc->corrupt_bio_flags);
443
444 break;
445
446 case STATUSTYPE_IMA:
447 result[0] = '\0';
448 break;
449 }
450}
451
452static int flakey_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
453{
454 struct flakey_c *fc = ti->private;
455
456 *bdev = fc->dev->bdev;
457
458 /*
459 * Only pass ioctls through if the device sizes match exactly.
460 */
461 if (fc->start || ti->len != bdev_nr_sectors((*bdev)))
462 return 1;
463 return 0;
464}
465
466#ifdef CONFIG_BLK_DEV_ZONED
467static int flakey_report_zones(struct dm_target *ti,
468 struct dm_report_zones_args *args, unsigned int nr_zones)
469{
470 struct flakey_c *fc = ti->private;
471
472 return dm_report_zones(fc->dev->bdev, fc->start,
473 flakey_map_sector(ti, args->next_sector),
474 args, nr_zones);
475}
476#else
477#define flakey_report_zones NULL
478#endif
479
480static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
481{
482 struct flakey_c *fc = ti->private;
483
484 return fn(ti, fc->dev, fc->start, ti->len, data);
485}
486
487static struct target_type flakey_target = {
488 .name = "flakey",
489 .version = {1, 5, 0},
490 .features = DM_TARGET_ZONED_HM | DM_TARGET_PASSES_CRYPTO,
491 .report_zones = flakey_report_zones,
492 .module = THIS_MODULE,
493 .ctr = flakey_ctr,
494 .dtr = flakey_dtr,
495 .map = flakey_map,
496 .end_io = flakey_end_io,
497 .status = flakey_status,
498 .prepare_ioctl = flakey_prepare_ioctl,
499 .iterate_devices = flakey_iterate_devices,
500};
501
502static int __init dm_flakey_init(void)
503{
504 int r = dm_register_target(&flakey_target);
505
506 if (r < 0)
507 DMERR("register failed %d", r);
508
509 return r;
510}
511
512static void __exit dm_flakey_exit(void)
513{
514 dm_unregister_target(&flakey_target);
515}
516
517/* Module hooks */
518module_init(dm_flakey_init);
519module_exit(dm_flakey_exit);
520
521MODULE_DESCRIPTION(DM_NAME " flakey target");
522MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
523MODULE_LICENSE("GPL");
1/*
2 * Copyright (C) 2003 Sistina Software (UK) Limited.
3 * Copyright (C) 2004, 2010-2011 Red Hat, Inc. All rights reserved.
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
18#define all_corrupt_bio_flags_match(bio, fc) \
19 (((bio)->bi_rw & (fc)->corrupt_bio_flags) == (fc)->corrupt_bio_flags)
20
21/*
22 * Flakey: Used for testing only, simulates intermittent,
23 * catastrophic device failure.
24 */
25struct flakey_c {
26 struct dm_dev *dev;
27 unsigned long start_time;
28 sector_t start;
29 unsigned up_interval;
30 unsigned down_interval;
31 unsigned long flags;
32 unsigned corrupt_bio_byte;
33 unsigned corrupt_bio_rw;
34 unsigned corrupt_bio_value;
35 unsigned corrupt_bio_flags;
36};
37
38enum feature_flag_bits {
39 DROP_WRITES
40};
41
42struct per_bio_data {
43 bool bio_submitted;
44};
45
46static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
47 struct dm_target *ti)
48{
49 int r;
50 unsigned argc;
51 const char *arg_name;
52
53 static struct dm_arg _args[] = {
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"},
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)
66 return r;
67
68 while (argc) {
69 arg_name = dm_shift_arg(as);
70 argc--;
71
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
84 /*
85 * corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>
86 */
87 if (!strcasecmp(arg_name, "corrupt_bio_byte")) {
88 if (!argc) {
89 ti->error = "Feature corrupt_bio_byte requires parameters";
90 return -EINVAL;
91 }
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
131 ti->error = "Unrecognised flakey feature requested";
132 return -EINVAL;
133 }
134
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;
141}
142
143/*
144 * Construct a flakey mapping:
145 * <dev_path> <offset> <up interval> <down interval> [<#feature args> [<arg>]*]
146 *
147 * Feature args:
148 * [drop_writes]
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.
154 */
155static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv)
156{
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;
163 struct flakey_c *fc;
164 unsigned long long tmpll;
165 struct dm_arg_set as;
166 const char *devname;
167 char dummy;
168
169 as.argc = argc;
170 as.argv = argv;
171
172 if (argc < 4) {
173 ti->error = "Invalid argument count";
174 return -EINVAL;
175 }
176
177 fc = kzalloc(sizeof(*fc), GFP_KERNEL);
178 if (!fc) {
179 ti->error = "Cannot allocate context";
180 return -ENOMEM;
181 }
182 fc->start_time = jiffies;
183
184 devname = dm_shift_arg(&as);
185
186 if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1) {
187 ti->error = "Invalid device sector";
188 goto bad;
189 }
190 fc->start = tmpll;
191
192 r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
193 if (r)
194 goto bad;
195
196 r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
197 if (r)
198 goto bad;
199
200 if (!(fc->up_interval + fc->down_interval)) {
201 ti->error = "Total (up + down) interval is zero";
202 goto bad;
203 }
204
205 if (fc->up_interval + fc->down_interval < fc->up_interval) {
206 ti->error = "Interval overflow";
207 goto bad;
208 }
209
210 r = parse_features(&as, fc, ti);
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";
216 goto bad;
217 }
218
219 ti->num_flush_bios = 1;
220 ti->num_discard_bios = 1;
221 ti->per_bio_data_size = sizeof(struct per_bio_data);
222 ti->private = fc;
223 return 0;
224
225bad:
226 kfree(fc);
227 return -EINVAL;
228}
229
230static 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
238static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector)
239{
240 struct flakey_c *fc = ti->private;
241
242 return fc->start + dm_target_offset(ti, bi_sector);
243}
244
245static 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_iter.bi_sector =
252 flakey_map_sector(ti, bio->bi_iter.bi_sector);
253}
254
255static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc)
256{
257 unsigned bio_bytes = bio_cur_bytes(bio);
258 char *data = bio_data(bio);
259
260 /*
261 * Overwrite the Nth byte of the data returned.
262 */
263 if (data && bio_bytes >= fc->corrupt_bio_byte) {
264 data[fc->corrupt_bio_byte - 1] = fc->corrupt_bio_value;
265
266 DMDEBUG("Corrupting data bio=%p by writing %u to byte %u "
267 "(rw=%c bi_rw=%lu bi_sector=%llu cur_bytes=%u)\n",
268 bio, fc->corrupt_bio_value, fc->corrupt_bio_byte,
269 (bio_data_dir(bio) == WRITE) ? 'w' : 'r', bio->bi_rw,
270 (unsigned long long)bio->bi_iter.bi_sector, bio_bytes);
271 }
272}
273
274static int flakey_map(struct dm_target *ti, struct bio *bio)
275{
276 struct flakey_c *fc = ti->private;
277 unsigned elapsed;
278 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
279 pb->bio_submitted = false;
280
281 /* Are we alive ? */
282 elapsed = (jiffies - fc->start_time) / HZ;
283 if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
284 /*
285 * Flag this bio as submitted while down.
286 */
287 pb->bio_submitted = true;
288
289 /*
290 * Map reads as normal.
291 */
292 if (bio_data_dir(bio) == READ)
293 goto map_bio;
294
295 /*
296 * Drop writes?
297 */
298 if (test_bit(DROP_WRITES, &fc->flags)) {
299 bio_endio(bio, 0);
300 return DM_MAPIO_SUBMITTED;
301 }
302
303 /*
304 * Corrupt matching writes.
305 */
306 if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == WRITE)) {
307 if (all_corrupt_bio_flags_match(bio, fc))
308 corrupt_bio_data(bio, fc);
309 goto map_bio;
310 }
311
312 /*
313 * By default, error all I/O.
314 */
315 return -EIO;
316 }
317
318map_bio:
319 flakey_map_bio(ti, bio);
320
321 return DM_MAPIO_REMAPPED;
322}
323
324static int flakey_end_io(struct dm_target *ti, struct bio *bio, int error)
325{
326 struct flakey_c *fc = ti->private;
327 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
328
329 /*
330 * Corrupt successful READs while in down state.
331 * If flags were specified, only corrupt those that match.
332 */
333 if (fc->corrupt_bio_byte && !error && pb->bio_submitted &&
334 (bio_data_dir(bio) == READ) && (fc->corrupt_bio_rw == READ) &&
335 all_corrupt_bio_flags_match(bio, fc))
336 corrupt_bio_data(bio, fc);
337
338 return error;
339}
340
341static void flakey_status(struct dm_target *ti, status_type_t type,
342 unsigned status_flags, char *result, unsigned maxlen)
343{
344 unsigned sz = 0;
345 struct flakey_c *fc = ti->private;
346 unsigned drop_writes;
347
348 switch (type) {
349 case STATUSTYPE_INFO:
350 result[0] = '\0';
351 break;
352
353 case STATUSTYPE_TABLE:
354 DMEMIT("%s %llu %u %u ", fc->dev->name,
355 (unsigned long long)fc->start, fc->up_interval,
356 fc->down_interval);
357
358 drop_writes = test_bit(DROP_WRITES, &fc->flags);
359 DMEMIT("%u ", drop_writes + (fc->corrupt_bio_byte > 0) * 5);
360
361 if (drop_writes)
362 DMEMIT("drop_writes ");
363
364 if (fc->corrupt_bio_byte)
365 DMEMIT("corrupt_bio_byte %u %c %u %u ",
366 fc->corrupt_bio_byte,
367 (fc->corrupt_bio_rw == WRITE) ? 'w' : 'r',
368 fc->corrupt_bio_value, fc->corrupt_bio_flags);
369
370 break;
371 }
372}
373
374static int flakey_ioctl(struct dm_target *ti, unsigned int cmd, unsigned long arg)
375{
376 struct flakey_c *fc = ti->private;
377 struct dm_dev *dev = fc->dev;
378 int r = 0;
379
380 /*
381 * Only pass ioctls through if the device sizes match exactly.
382 */
383 if (fc->start ||
384 ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
385 r = scsi_verify_blk_ioctl(NULL, cmd);
386
387 return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg);
388}
389
390static int flakey_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
391 struct bio_vec *biovec, int max_size)
392{
393 struct flakey_c *fc = ti->private;
394 struct request_queue *q = bdev_get_queue(fc->dev->bdev);
395
396 if (!q->merge_bvec_fn)
397 return max_size;
398
399 bvm->bi_bdev = fc->dev->bdev;
400 bvm->bi_sector = flakey_map_sector(ti, bvm->bi_sector);
401
402 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
403}
404
405static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
406{
407 struct flakey_c *fc = ti->private;
408
409 return fn(ti, fc->dev, fc->start, ti->len, data);
410}
411
412static struct target_type flakey_target = {
413 .name = "flakey",
414 .version = {1, 3, 1},
415 .module = THIS_MODULE,
416 .ctr = flakey_ctr,
417 .dtr = flakey_dtr,
418 .map = flakey_map,
419 .end_io = flakey_end_io,
420 .status = flakey_status,
421 .ioctl = flakey_ioctl,
422 .merge = flakey_merge,
423 .iterate_devices = flakey_iterate_devices,
424};
425
426static int __init dm_flakey_init(void)
427{
428 int r = dm_register_target(&flakey_target);
429
430 if (r < 0)
431 DMERR("register failed %d", r);
432
433 return r;
434}
435
436static void __exit dm_flakey_exit(void)
437{
438 dm_unregister_target(&flakey_target);
439}
440
441/* Module hooks */
442module_init(dm_flakey_init);
443module_exit(dm_flakey_exit);
444
445MODULE_DESCRIPTION(DM_NAME " flakey target");
446MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
447MODULE_LICENSE("GPL");