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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
42static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
43 struct dm_target *ti)
44{
45 int r;
46 unsigned argc;
47 const char *arg_name;
48
49 static struct dm_arg _args[] = {
50 {0, 6, "Invalid number of feature args"},
51 {1, UINT_MAX, "Invalid corrupt bio byte"},
52 {0, 255, "Invalid corrupt value to write into bio byte (0-255)"},
53 {0, UINT_MAX, "Invalid corrupt bio flags mask"},
54 };
55
56 /* No feature arguments supplied. */
57 if (!as->argc)
58 return 0;
59
60 r = dm_read_arg_group(_args, as, &argc, &ti->error);
61 if (r)
62 return r;
63
64 while (argc) {
65 arg_name = dm_shift_arg(as);
66 argc--;
67
68 /*
69 * drop_writes
70 */
71 if (!strcasecmp(arg_name, "drop_writes")) {
72 if (test_and_set_bit(DROP_WRITES, &fc->flags)) {
73 ti->error = "Feature drop_writes duplicated";
74 return -EINVAL;
75 }
76
77 continue;
78 }
79
80 /*
81 * corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>
82 */
83 if (!strcasecmp(arg_name, "corrupt_bio_byte")) {
84 if (!argc) {
85 ti->error = "Feature corrupt_bio_byte requires parameters";
86 return -EINVAL;
87 }
88
89 r = dm_read_arg(_args + 1, as, &fc->corrupt_bio_byte, &ti->error);
90 if (r)
91 return r;
92 argc--;
93
94 /*
95 * Direction r or w?
96 */
97 arg_name = dm_shift_arg(as);
98 if (!strcasecmp(arg_name, "w"))
99 fc->corrupt_bio_rw = WRITE;
100 else if (!strcasecmp(arg_name, "r"))
101 fc->corrupt_bio_rw = READ;
102 else {
103 ti->error = "Invalid corrupt bio direction (r or w)";
104 return -EINVAL;
105 }
106 argc--;
107
108 /*
109 * Value of byte (0-255) to write in place of correct one.
110 */
111 r = dm_read_arg(_args + 2, as, &fc->corrupt_bio_value, &ti->error);
112 if (r)
113 return r;
114 argc--;
115
116 /*
117 * Only corrupt bios with these flags set.
118 */
119 r = dm_read_arg(_args + 3, as, &fc->corrupt_bio_flags, &ti->error);
120 if (r)
121 return r;
122 argc--;
123
124 continue;
125 }
126
127 ti->error = "Unrecognised flakey feature requested";
128 return -EINVAL;
129 }
130
131 if (test_bit(DROP_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) {
132 ti->error = "drop_writes is incompatible with corrupt_bio_byte with the WRITE flag set";
133 return -EINVAL;
134 }
135
136 return 0;
137}
138
139/*
140 * Construct a flakey mapping:
141 * <dev_path> <offset> <up interval> <down interval> [<#feature args> [<arg>]*]
142 *
143 * Feature args:
144 * [drop_writes]
145 * [corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>]
146 *
147 * Nth_byte starts from 1 for the first byte.
148 * Direction is r for READ or w for WRITE.
149 * bio_flags is ignored if 0.
150 */
151static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv)
152{
153 static struct dm_arg _args[] = {
154 {0, UINT_MAX, "Invalid up interval"},
155 {0, UINT_MAX, "Invalid down interval"},
156 };
157
158 int r;
159 struct flakey_c *fc;
160 unsigned long long tmpll;
161 struct dm_arg_set as;
162 const char *devname;
163
164 as.argc = argc;
165 as.argv = argv;
166
167 if (argc < 4) {
168 ti->error = "Invalid argument count";
169 return -EINVAL;
170 }
171
172 fc = kzalloc(sizeof(*fc), GFP_KERNEL);
173 if (!fc) {
174 ti->error = "Cannot allocate linear context";
175 return -ENOMEM;
176 }
177 fc->start_time = jiffies;
178
179 devname = dm_shift_arg(&as);
180
181 if (sscanf(dm_shift_arg(&as), "%llu", &tmpll) != 1) {
182 ti->error = "Invalid device sector";
183 goto bad;
184 }
185 fc->start = tmpll;
186
187 r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
188 if (r)
189 goto bad;
190
191 r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
192 if (r)
193 goto bad;
194
195 if (!(fc->up_interval + fc->down_interval)) {
196 ti->error = "Total (up + down) interval is zero";
197 goto bad;
198 }
199
200 if (fc->up_interval + fc->down_interval < fc->up_interval) {
201 ti->error = "Interval overflow";
202 goto bad;
203 }
204
205 r = parse_features(&as, fc, ti);
206 if (r)
207 goto bad;
208
209 if (dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev)) {
210 ti->error = "Device lookup failed";
211 goto bad;
212 }
213
214 ti->num_flush_requests = 1;
215 ti->num_discard_requests = 1;
216 ti->private = fc;
217 return 0;
218
219bad:
220 kfree(fc);
221 return -EINVAL;
222}
223
224static void flakey_dtr(struct dm_target *ti)
225{
226 struct flakey_c *fc = ti->private;
227
228 dm_put_device(ti, fc->dev);
229 kfree(fc);
230}
231
232static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector)
233{
234 struct flakey_c *fc = ti->private;
235
236 return fc->start + dm_target_offset(ti, bi_sector);
237}
238
239static void flakey_map_bio(struct dm_target *ti, struct bio *bio)
240{
241 struct flakey_c *fc = ti->private;
242
243 bio->bi_bdev = fc->dev->bdev;
244 if (bio_sectors(bio))
245 bio->bi_sector = flakey_map_sector(ti, bio->bi_sector);
246}
247
248static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc)
249{
250 unsigned bio_bytes = bio_cur_bytes(bio);
251 char *data = bio_data(bio);
252
253 /*
254 * Overwrite the Nth byte of the data returned.
255 */
256 if (data && bio_bytes >= fc->corrupt_bio_byte) {
257 data[fc->corrupt_bio_byte - 1] = fc->corrupt_bio_value;
258
259 DMDEBUG("Corrupting data bio=%p by writing %u to byte %u "
260 "(rw=%c bi_rw=%lu bi_sector=%llu cur_bytes=%u)\n",
261 bio, fc->corrupt_bio_value, fc->corrupt_bio_byte,
262 (bio_data_dir(bio) == WRITE) ? 'w' : 'r',
263 bio->bi_rw, (unsigned long long)bio->bi_sector, bio_bytes);
264 }
265}
266
267static int flakey_map(struct dm_target *ti, struct bio *bio,
268 union map_info *map_context)
269{
270 struct flakey_c *fc = ti->private;
271 unsigned elapsed;
272
273 /* Are we alive ? */
274 elapsed = (jiffies - fc->start_time) / HZ;
275 if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
276 /*
277 * Flag this bio as submitted while down.
278 */
279 map_context->ll = 1;
280
281 /*
282 * Map reads as normal.
283 */
284 if (bio_data_dir(bio) == READ)
285 goto map_bio;
286
287 /*
288 * Drop writes?
289 */
290 if (test_bit(DROP_WRITES, &fc->flags)) {
291 bio_endio(bio, 0);
292 return DM_MAPIO_SUBMITTED;
293 }
294
295 /*
296 * Corrupt matching writes.
297 */
298 if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == WRITE)) {
299 if (all_corrupt_bio_flags_match(bio, fc))
300 corrupt_bio_data(bio, fc);
301 goto map_bio;
302 }
303
304 /*
305 * By default, error all I/O.
306 */
307 return -EIO;
308 }
309
310map_bio:
311 flakey_map_bio(ti, bio);
312
313 return DM_MAPIO_REMAPPED;
314}
315
316static int flakey_end_io(struct dm_target *ti, struct bio *bio,
317 int error, union map_info *map_context)
318{
319 struct flakey_c *fc = ti->private;
320 unsigned bio_submitted_while_down = map_context->ll;
321
322 /*
323 * Corrupt successful READs while in down state.
324 * If flags were specified, only corrupt those that match.
325 */
326 if (!error && bio_submitted_while_down &&
327 (bio_data_dir(bio) == READ) && (fc->corrupt_bio_rw == READ) &&
328 all_corrupt_bio_flags_match(bio, fc))
329 corrupt_bio_data(bio, fc);
330
331 return error;
332}
333
334static int flakey_status(struct dm_target *ti, status_type_t type,
335 char *result, unsigned int maxlen)
336{
337 unsigned sz = 0;
338 struct flakey_c *fc = ti->private;
339 unsigned drop_writes;
340
341 switch (type) {
342 case STATUSTYPE_INFO:
343 result[0] = '\0';
344 break;
345
346 case STATUSTYPE_TABLE:
347 DMEMIT("%s %llu %u %u ", fc->dev->name,
348 (unsigned long long)fc->start, fc->up_interval,
349 fc->down_interval);
350
351 drop_writes = test_bit(DROP_WRITES, &fc->flags);
352 DMEMIT("%u ", drop_writes + (fc->corrupt_bio_byte > 0) * 5);
353
354 if (drop_writes)
355 DMEMIT("drop_writes ");
356
357 if (fc->corrupt_bio_byte)
358 DMEMIT("corrupt_bio_byte %u %c %u %u ",
359 fc->corrupt_bio_byte,
360 (fc->corrupt_bio_rw == WRITE) ? 'w' : 'r',
361 fc->corrupt_bio_value, fc->corrupt_bio_flags);
362
363 break;
364 }
365 return 0;
366}
367
368static int flakey_ioctl(struct dm_target *ti, unsigned int cmd, unsigned long arg)
369{
370 struct flakey_c *fc = ti->private;
371
372 return __blkdev_driver_ioctl(fc->dev->bdev, fc->dev->mode, cmd, arg);
373}
374
375static int flakey_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
376 struct bio_vec *biovec, int max_size)
377{
378 struct flakey_c *fc = ti->private;
379 struct request_queue *q = bdev_get_queue(fc->dev->bdev);
380
381 if (!q->merge_bvec_fn)
382 return max_size;
383
384 bvm->bi_bdev = fc->dev->bdev;
385 bvm->bi_sector = flakey_map_sector(ti, bvm->bi_sector);
386
387 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
388}
389
390static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
391{
392 struct flakey_c *fc = ti->private;
393
394 return fn(ti, fc->dev, fc->start, ti->len, data);
395}
396
397static struct target_type flakey_target = {
398 .name = "flakey",
399 .version = {1, 2, 0},
400 .module = THIS_MODULE,
401 .ctr = flakey_ctr,
402 .dtr = flakey_dtr,
403 .map = flakey_map,
404 .end_io = flakey_end_io,
405 .status = flakey_status,
406 .ioctl = flakey_ioctl,
407 .merge = flakey_merge,
408 .iterate_devices = flakey_iterate_devices,
409};
410
411static int __init dm_flakey_init(void)
412{
413 int r = dm_register_target(&flakey_target);
414
415 if (r < 0)
416 DMERR("register failed %d", r);
417
418 return r;
419}
420
421static void __exit dm_flakey_exit(void)
422{
423 dm_unregister_target(&flakey_target);
424}
425
426/* Module hooks */
427module_init(dm_flakey_init);
428module_exit(dm_flakey_exit);
429
430MODULE_DESCRIPTION(DM_NAME " flakey target");
431MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
432MODULE_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
42static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
43 struct dm_target *ti)
44{
45 int r;
46 unsigned argc;
47 const char *arg_name;
48
49 static struct dm_arg _args[] = {
50 {0, 6, "Invalid number of feature args"},
51 {1, UINT_MAX, "Invalid corrupt bio byte"},
52 {0, 255, "Invalid corrupt value to write into bio byte (0-255)"},
53 {0, UINT_MAX, "Invalid corrupt bio flags mask"},
54 };
55
56 /* No feature arguments supplied. */
57 if (!as->argc)
58 return 0;
59
60 r = dm_read_arg_group(_args, as, &argc, &ti->error);
61 if (r)
62 return r;
63
64 while (argc) {
65 arg_name = dm_shift_arg(as);
66 argc--;
67
68 /*
69 * drop_writes
70 */
71 if (!strcasecmp(arg_name, "drop_writes")) {
72 if (test_and_set_bit(DROP_WRITES, &fc->flags)) {
73 ti->error = "Feature drop_writes duplicated";
74 return -EINVAL;
75 }
76
77 continue;
78 }
79
80 /*
81 * corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>
82 */
83 if (!strcasecmp(arg_name, "corrupt_bio_byte")) {
84 if (!argc) {
85 ti->error = "Feature corrupt_bio_byte requires parameters";
86 return -EINVAL;
87 }
88
89 r = dm_read_arg(_args + 1, as, &fc->corrupt_bio_byte, &ti->error);
90 if (r)
91 return r;
92 argc--;
93
94 /*
95 * Direction r or w?
96 */
97 arg_name = dm_shift_arg(as);
98 if (!strcasecmp(arg_name, "w"))
99 fc->corrupt_bio_rw = WRITE;
100 else if (!strcasecmp(arg_name, "r"))
101 fc->corrupt_bio_rw = READ;
102 else {
103 ti->error = "Invalid corrupt bio direction (r or w)";
104 return -EINVAL;
105 }
106 argc--;
107
108 /*
109 * Value of byte (0-255) to write in place of correct one.
110 */
111 r = dm_read_arg(_args + 2, as, &fc->corrupt_bio_value, &ti->error);
112 if (r)
113 return r;
114 argc--;
115
116 /*
117 * Only corrupt bios with these flags set.
118 */
119 r = dm_read_arg(_args + 3, as, &fc->corrupt_bio_flags, &ti->error);
120 if (r)
121 return r;
122 argc--;
123
124 continue;
125 }
126
127 ti->error = "Unrecognised flakey feature requested";
128 return -EINVAL;
129 }
130
131 if (test_bit(DROP_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) {
132 ti->error = "drop_writes is incompatible with corrupt_bio_byte with the WRITE flag set";
133 return -EINVAL;
134 }
135
136 return 0;
137}
138
139/*
140 * Construct a flakey mapping:
141 * <dev_path> <offset> <up interval> <down interval> [<#feature args> [<arg>]*]
142 *
143 * Feature args:
144 * [drop_writes]
145 * [corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>]
146 *
147 * Nth_byte starts from 1 for the first byte.
148 * Direction is r for READ or w for WRITE.
149 * bio_flags is ignored if 0.
150 */
151static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv)
152{
153 static struct dm_arg _args[] = {
154 {0, UINT_MAX, "Invalid up interval"},
155 {0, UINT_MAX, "Invalid down interval"},
156 };
157
158 int r;
159 struct flakey_c *fc;
160 unsigned long long tmpll;
161 struct dm_arg_set as;
162 const char *devname;
163 char dummy;
164
165 as.argc = argc;
166 as.argv = argv;
167
168 if (argc < 4) {
169 ti->error = "Invalid argument count";
170 return -EINVAL;
171 }
172
173 fc = kzalloc(sizeof(*fc), GFP_KERNEL);
174 if (!fc) {
175 ti->error = "Cannot allocate linear context";
176 return -ENOMEM;
177 }
178 fc->start_time = jiffies;
179
180 devname = dm_shift_arg(&as);
181
182 if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1) {
183 ti->error = "Invalid device sector";
184 goto bad;
185 }
186 fc->start = tmpll;
187
188 r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
189 if (r)
190 goto bad;
191
192 r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
193 if (r)
194 goto bad;
195
196 if (!(fc->up_interval + fc->down_interval)) {
197 ti->error = "Total (up + down) interval is zero";
198 goto bad;
199 }
200
201 if (fc->up_interval + fc->down_interval < fc->up_interval) {
202 ti->error = "Interval overflow";
203 goto bad;
204 }
205
206 r = parse_features(&as, fc, ti);
207 if (r)
208 goto bad;
209
210 if (dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev)) {
211 ti->error = "Device lookup failed";
212 goto bad;
213 }
214
215 ti->num_flush_requests = 1;
216 ti->num_discard_requests = 1;
217 ti->private = fc;
218 return 0;
219
220bad:
221 kfree(fc);
222 return -EINVAL;
223}
224
225static void flakey_dtr(struct dm_target *ti)
226{
227 struct flakey_c *fc = ti->private;
228
229 dm_put_device(ti, fc->dev);
230 kfree(fc);
231}
232
233static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector)
234{
235 struct flakey_c *fc = ti->private;
236
237 return fc->start + dm_target_offset(ti, bi_sector);
238}
239
240static void flakey_map_bio(struct dm_target *ti, struct bio *bio)
241{
242 struct flakey_c *fc = ti->private;
243
244 bio->bi_bdev = fc->dev->bdev;
245 if (bio_sectors(bio))
246 bio->bi_sector = flakey_map_sector(ti, bio->bi_sector);
247}
248
249static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc)
250{
251 unsigned bio_bytes = bio_cur_bytes(bio);
252 char *data = bio_data(bio);
253
254 /*
255 * Overwrite the Nth byte of the data returned.
256 */
257 if (data && bio_bytes >= fc->corrupt_bio_byte) {
258 data[fc->corrupt_bio_byte - 1] = fc->corrupt_bio_value;
259
260 DMDEBUG("Corrupting data bio=%p by writing %u to byte %u "
261 "(rw=%c bi_rw=%lu bi_sector=%llu cur_bytes=%u)\n",
262 bio, fc->corrupt_bio_value, fc->corrupt_bio_byte,
263 (bio_data_dir(bio) == WRITE) ? 'w' : 'r',
264 bio->bi_rw, (unsigned long long)bio->bi_sector, bio_bytes);
265 }
266}
267
268static int flakey_map(struct dm_target *ti, struct bio *bio,
269 union map_info *map_context)
270{
271 struct flakey_c *fc = ti->private;
272 unsigned elapsed;
273
274 /* Are we alive ? */
275 elapsed = (jiffies - fc->start_time) / HZ;
276 if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
277 /*
278 * Flag this bio as submitted while down.
279 */
280 map_context->ll = 1;
281
282 /*
283 * Map reads as normal.
284 */
285 if (bio_data_dir(bio) == READ)
286 goto map_bio;
287
288 /*
289 * Drop writes?
290 */
291 if (test_bit(DROP_WRITES, &fc->flags)) {
292 bio_endio(bio, 0);
293 return DM_MAPIO_SUBMITTED;
294 }
295
296 /*
297 * Corrupt matching writes.
298 */
299 if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == WRITE)) {
300 if (all_corrupt_bio_flags_match(bio, fc))
301 corrupt_bio_data(bio, fc);
302 goto map_bio;
303 }
304
305 /*
306 * By default, error all I/O.
307 */
308 return -EIO;
309 }
310
311map_bio:
312 flakey_map_bio(ti, bio);
313
314 return DM_MAPIO_REMAPPED;
315}
316
317static int flakey_end_io(struct dm_target *ti, struct bio *bio,
318 int error, union map_info *map_context)
319{
320 struct flakey_c *fc = ti->private;
321 unsigned bio_submitted_while_down = map_context->ll;
322
323 /*
324 * Corrupt successful READs while in down state.
325 * If flags were specified, only corrupt those that match.
326 */
327 if (fc->corrupt_bio_byte && !error && bio_submitted_while_down &&
328 (bio_data_dir(bio) == READ) && (fc->corrupt_bio_rw == READ) &&
329 all_corrupt_bio_flags_match(bio, fc))
330 corrupt_bio_data(bio, fc);
331
332 return error;
333}
334
335static int flakey_status(struct dm_target *ti, status_type_t type,
336 char *result, unsigned int maxlen)
337{
338 unsigned sz = 0;
339 struct flakey_c *fc = ti->private;
340 unsigned drop_writes;
341
342 switch (type) {
343 case STATUSTYPE_INFO:
344 result[0] = '\0';
345 break;
346
347 case STATUSTYPE_TABLE:
348 DMEMIT("%s %llu %u %u ", fc->dev->name,
349 (unsigned long long)fc->start, fc->up_interval,
350 fc->down_interval);
351
352 drop_writes = test_bit(DROP_WRITES, &fc->flags);
353 DMEMIT("%u ", drop_writes + (fc->corrupt_bio_byte > 0) * 5);
354
355 if (drop_writes)
356 DMEMIT("drop_writes ");
357
358 if (fc->corrupt_bio_byte)
359 DMEMIT("corrupt_bio_byte %u %c %u %u ",
360 fc->corrupt_bio_byte,
361 (fc->corrupt_bio_rw == WRITE) ? 'w' : 'r',
362 fc->corrupt_bio_value, fc->corrupt_bio_flags);
363
364 break;
365 }
366 return 0;
367}
368
369static int flakey_ioctl(struct dm_target *ti, unsigned int cmd, unsigned long arg)
370{
371 struct flakey_c *fc = ti->private;
372 struct dm_dev *dev = fc->dev;
373 int r = 0;
374
375 /*
376 * Only pass ioctls through if the device sizes match exactly.
377 */
378 if (fc->start ||
379 ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
380 r = scsi_verify_blk_ioctl(NULL, cmd);
381
382 return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg);
383}
384
385static int flakey_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
386 struct bio_vec *biovec, int max_size)
387{
388 struct flakey_c *fc = ti->private;
389 struct request_queue *q = bdev_get_queue(fc->dev->bdev);
390
391 if (!q->merge_bvec_fn)
392 return max_size;
393
394 bvm->bi_bdev = fc->dev->bdev;
395 bvm->bi_sector = flakey_map_sector(ti, bvm->bi_sector);
396
397 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
398}
399
400static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
401{
402 struct flakey_c *fc = ti->private;
403
404 return fn(ti, fc->dev, fc->start, ti->len, data);
405}
406
407static struct target_type flakey_target = {
408 .name = "flakey",
409 .version = {1, 2, 0},
410 .module = THIS_MODULE,
411 .ctr = flakey_ctr,
412 .dtr = flakey_dtr,
413 .map = flakey_map,
414 .end_io = flakey_end_io,
415 .status = flakey_status,
416 .ioctl = flakey_ioctl,
417 .merge = flakey_merge,
418 .iterate_devices = flakey_iterate_devices,
419};
420
421static int __init dm_flakey_init(void)
422{
423 int r = dm_register_target(&flakey_target);
424
425 if (r < 0)
426 DMERR("register failed %d", r);
427
428 return r;
429}
430
431static void __exit dm_flakey_exit(void)
432{
433 dm_unregister_target(&flakey_target);
434}
435
436/* Module hooks */
437module_init(dm_flakey_init);
438module_exit(dm_flakey_exit);
439
440MODULE_DESCRIPTION(DM_NAME " flakey target");
441MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
442MODULE_LICENSE("GPL");