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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
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 r = -EINVAL;
187 if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1) {
188 ti->error = "Invalid device sector";
189 goto bad;
190 }
191 fc->start = tmpll;
192
193 r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
194 if (r)
195 goto bad;
196
197 r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
198 if (r)
199 goto bad;
200
201 if (!(fc->up_interval + fc->down_interval)) {
202 ti->error = "Total (up + down) interval is zero";
203 goto bad;
204 }
205
206 if (fc->up_interval + fc->down_interval < fc->up_interval) {
207 ti->error = "Interval overflow";
208 goto bad;
209 }
210
211 r = parse_features(&as, fc, ti);
212 if (r)
213 goto bad;
214
215 r = dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev);
216 if (r) {
217 ti->error = "Device lookup failed";
218 goto bad;
219 }
220
221 ti->num_flush_bios = 1;
222 ti->num_discard_bios = 1;
223 ti->per_io_data_size = sizeof(struct per_bio_data);
224 ti->private = fc;
225 return 0;
226
227bad:
228 kfree(fc);
229 return r;
230}
231
232static 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
240static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector)
241{
242 struct flakey_c *fc = ti->private;
243
244 return fc->start + dm_target_offset(ti, bi_sector);
245}
246
247static 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))
253 bio->bi_iter.bi_sector =
254 flakey_map_sector(ti, bio->bi_iter.bi_sector);
255}
256
257static 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 "
269 "(rw=%c bi_rw=%lu bi_sector=%llu cur_bytes=%u)\n",
270 bio, fc->corrupt_bio_value, fc->corrupt_bio_byte,
271 (bio_data_dir(bio) == WRITE) ? 'w' : 'r', bio->bi_rw,
272 (unsigned long long)bio->bi_iter.bi_sector, bio_bytes);
273 }
274}
275
276static int flakey_map(struct dm_target *ti, struct bio *bio)
277{
278 struct flakey_c *fc = ti->private;
279 unsigned elapsed;
280 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
281 pb->bio_submitted = false;
282
283 /* Are we alive ? */
284 elapsed = (jiffies - fc->start_time) / HZ;
285 if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
286 /*
287 * Flag this bio as submitted while down.
288 */
289 pb->bio_submitted = true;
290
291 /*
292 * Map reads as normal.
293 */
294 if (bio_data_dir(bio) == READ)
295 goto map_bio;
296
297 /*
298 * Drop writes?
299 */
300 if (test_bit(DROP_WRITES, &fc->flags)) {
301 bio_endio(bio);
302 return DM_MAPIO_SUBMITTED;
303 }
304
305 /*
306 * Corrupt matching writes.
307 */
308 if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == WRITE)) {
309 if (all_corrupt_bio_flags_match(bio, fc))
310 corrupt_bio_data(bio, fc);
311 goto map_bio;
312 }
313
314 /*
315 * By default, error all I/O.
316 */
317 return -EIO;
318 }
319
320map_bio:
321 flakey_map_bio(ti, bio);
322
323 return DM_MAPIO_REMAPPED;
324}
325
326static int flakey_end_io(struct dm_target *ti, struct bio *bio, int error)
327{
328 struct flakey_c *fc = ti->private;
329 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
330
331 /*
332 * Corrupt successful READs while in down state.
333 * If flags were specified, only corrupt those that match.
334 */
335 if (fc->corrupt_bio_byte && !error && pb->bio_submitted &&
336 (bio_data_dir(bio) == READ) && (fc->corrupt_bio_rw == READ) &&
337 all_corrupt_bio_flags_match(bio, fc))
338 corrupt_bio_data(bio, fc);
339
340 return error;
341}
342
343static void flakey_status(struct dm_target *ti, status_type_t type,
344 unsigned status_flags, char *result, unsigned maxlen)
345{
346 unsigned sz = 0;
347 struct flakey_c *fc = ti->private;
348 unsigned drop_writes;
349
350 switch (type) {
351 case STATUSTYPE_INFO:
352 result[0] = '\0';
353 break;
354
355 case STATUSTYPE_TABLE:
356 DMEMIT("%s %llu %u %u ", fc->dev->name,
357 (unsigned long long)fc->start, fc->up_interval,
358 fc->down_interval);
359
360 drop_writes = test_bit(DROP_WRITES, &fc->flags);
361 DMEMIT("%u ", drop_writes + (fc->corrupt_bio_byte > 0) * 5);
362
363 if (drop_writes)
364 DMEMIT("drop_writes ");
365
366 if (fc->corrupt_bio_byte)
367 DMEMIT("corrupt_bio_byte %u %c %u %u ",
368 fc->corrupt_bio_byte,
369 (fc->corrupt_bio_rw == WRITE) ? 'w' : 'r',
370 fc->corrupt_bio_value, fc->corrupt_bio_flags);
371
372 break;
373 }
374}
375
376static int flakey_prepare_ioctl(struct dm_target *ti,
377 struct block_device **bdev, fmode_t *mode)
378{
379 struct flakey_c *fc = ti->private;
380
381 *bdev = fc->dev->bdev;
382
383 /*
384 * Only pass ioctls through if the device sizes match exactly.
385 */
386 if (fc->start ||
387 ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT)
388 return 1;
389 return 0;
390}
391
392static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
393{
394 struct flakey_c *fc = ti->private;
395
396 return fn(ti, fc->dev, fc->start, ti->len, data);
397}
398
399static struct target_type flakey_target = {
400 .name = "flakey",
401 .version = {1, 3, 1},
402 .module = THIS_MODULE,
403 .ctr = flakey_ctr,
404 .dtr = flakey_dtr,
405 .map = flakey_map,
406 .end_io = flakey_end_io,
407 .status = flakey_status,
408 .prepare_ioctl = flakey_prepare_ioctl,
409 .iterate_devices = flakey_iterate_devices,
410};
411
412static int __init dm_flakey_init(void)
413{
414 int r = dm_register_target(&flakey_target);
415
416 if (r < 0)
417 DMERR("register failed %d", r);
418
419 return r;
420}
421
422static void __exit dm_flakey_exit(void)
423{
424 dm_unregister_target(&flakey_target);
425}
426
427/* Module hooks */
428module_init(dm_flakey_init);
429module_exit(dm_flakey_exit);
430
431MODULE_DESCRIPTION(DM_NAME " flakey target");
432MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
433MODULE_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_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 unsigned 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 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 /*
74 * drop_writes
75 */
76 if (!strcasecmp(arg_name, "drop_writes")) {
77 if (test_and_set_bit(DROP_WRITES, &fc->flags)) {
78 ti->error = "Feature drop_writes duplicated";
79 return -EINVAL;
80 } else if (test_bit(ERROR_WRITES, &fc->flags)) {
81 ti->error = "Feature drop_writes conflicts with feature error_writes";
82 return -EINVAL;
83 }
84
85 continue;
86 }
87
88 /*
89 * error_writes
90 */
91 if (!strcasecmp(arg_name, "error_writes")) {
92 if (test_and_set_bit(ERROR_WRITES, &fc->flags)) {
93 ti->error = "Feature error_writes duplicated";
94 return -EINVAL;
95
96 } else if (test_bit(DROP_WRITES, &fc->flags)) {
97 ti->error = "Feature error_writes conflicts with feature drop_writes";
98 return -EINVAL;
99 }
100
101 continue;
102 }
103
104 /*
105 * corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>
106 */
107 if (!strcasecmp(arg_name, "corrupt_bio_byte")) {
108 if (!argc) {
109 ti->error = "Feature corrupt_bio_byte requires parameters";
110 return -EINVAL;
111 }
112
113 r = dm_read_arg(_args + 1, as, &fc->corrupt_bio_byte, &ti->error);
114 if (r)
115 return r;
116 argc--;
117
118 /*
119 * Direction r or w?
120 */
121 arg_name = dm_shift_arg(as);
122 if (!strcasecmp(arg_name, "w"))
123 fc->corrupt_bio_rw = WRITE;
124 else if (!strcasecmp(arg_name, "r"))
125 fc->corrupt_bio_rw = READ;
126 else {
127 ti->error = "Invalid corrupt bio direction (r or w)";
128 return -EINVAL;
129 }
130 argc--;
131
132 /*
133 * Value of byte (0-255) to write in place of correct one.
134 */
135 r = dm_read_arg(_args + 2, as, &fc->corrupt_bio_value, &ti->error);
136 if (r)
137 return r;
138 argc--;
139
140 /*
141 * Only corrupt bios with these flags set.
142 */
143 r = dm_read_arg(_args + 3, as, &fc->corrupt_bio_flags, &ti->error);
144 if (r)
145 return r;
146 argc--;
147
148 continue;
149 }
150
151 ti->error = "Unrecognised flakey feature requested";
152 return -EINVAL;
153 }
154
155 if (test_bit(DROP_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) {
156 ti->error = "drop_writes is incompatible with corrupt_bio_byte with the WRITE flag set";
157 return -EINVAL;
158
159 } else if (test_bit(ERROR_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) {
160 ti->error = "error_writes is incompatible with corrupt_bio_byte with the WRITE flag set";
161 return -EINVAL;
162 }
163
164 return 0;
165}
166
167/*
168 * Construct a flakey mapping:
169 * <dev_path> <offset> <up interval> <down interval> [<#feature args> [<arg>]*]
170 *
171 * Feature args:
172 * [drop_writes]
173 * [corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>]
174 *
175 * Nth_byte starts from 1 for the first byte.
176 * Direction is r for READ or w for WRITE.
177 * bio_flags is ignored if 0.
178 */
179static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv)
180{
181 static struct dm_arg _args[] = {
182 {0, UINT_MAX, "Invalid up interval"},
183 {0, UINT_MAX, "Invalid down interval"},
184 };
185
186 int r;
187 struct flakey_c *fc;
188 unsigned long long tmpll;
189 struct dm_arg_set as;
190 const char *devname;
191 char dummy;
192
193 as.argc = argc;
194 as.argv = argv;
195
196 if (argc < 4) {
197 ti->error = "Invalid argument count";
198 return -EINVAL;
199 }
200
201 fc = kzalloc(sizeof(*fc), GFP_KERNEL);
202 if (!fc) {
203 ti->error = "Cannot allocate context";
204 return -ENOMEM;
205 }
206 fc->start_time = jiffies;
207
208 devname = dm_shift_arg(&as);
209
210 r = -EINVAL;
211 if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1) {
212 ti->error = "Invalid device sector";
213 goto bad;
214 }
215 fc->start = tmpll;
216
217 r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
218 if (r)
219 goto bad;
220
221 r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
222 if (r)
223 goto bad;
224
225 if (!(fc->up_interval + fc->down_interval)) {
226 ti->error = "Total (up + down) interval is zero";
227 r = -EINVAL;
228 goto bad;
229 }
230
231 if (fc->up_interval + fc->down_interval < fc->up_interval) {
232 ti->error = "Interval overflow";
233 r = -EINVAL;
234 goto bad;
235 }
236
237 r = parse_features(&as, fc, ti);
238 if (r)
239 goto bad;
240
241 r = dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev);
242 if (r) {
243 ti->error = "Device lookup failed";
244 goto bad;
245 }
246
247 ti->num_flush_bios = 1;
248 ti->num_discard_bios = 1;
249 ti->per_io_data_size = sizeof(struct per_bio_data);
250 ti->private = fc;
251 return 0;
252
253bad:
254 kfree(fc);
255 return r;
256}
257
258static void flakey_dtr(struct dm_target *ti)
259{
260 struct flakey_c *fc = ti->private;
261
262 dm_put_device(ti, fc->dev);
263 kfree(fc);
264}
265
266static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector)
267{
268 struct flakey_c *fc = ti->private;
269
270 return fc->start + dm_target_offset(ti, bi_sector);
271}
272
273static void flakey_map_bio(struct dm_target *ti, struct bio *bio)
274{
275 struct flakey_c *fc = ti->private;
276
277 bio->bi_bdev = fc->dev->bdev;
278 if (bio_sectors(bio))
279 bio->bi_iter.bi_sector =
280 flakey_map_sector(ti, bio->bi_iter.bi_sector);
281}
282
283static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc)
284{
285 unsigned bio_bytes = bio_cur_bytes(bio);
286 char *data = bio_data(bio);
287
288 /*
289 * Overwrite the Nth byte of the data returned.
290 */
291 if (data && bio_bytes >= fc->corrupt_bio_byte) {
292 data[fc->corrupt_bio_byte - 1] = fc->corrupt_bio_value;
293
294 DMDEBUG("Corrupting data bio=%p by writing %u to byte %u "
295 "(rw=%c bi_opf=%u bi_sector=%llu cur_bytes=%u)\n",
296 bio, fc->corrupt_bio_value, fc->corrupt_bio_byte,
297 (bio_data_dir(bio) == WRITE) ? 'w' : 'r', bio->bi_opf,
298 (unsigned long long)bio->bi_iter.bi_sector, bio_bytes);
299 }
300}
301
302static int flakey_map(struct dm_target *ti, struct bio *bio)
303{
304 struct flakey_c *fc = ti->private;
305 unsigned elapsed;
306 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
307 pb->bio_submitted = false;
308
309 /* Are we alive ? */
310 elapsed = (jiffies - fc->start_time) / HZ;
311 if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
312 /*
313 * Flag this bio as submitted while down.
314 */
315 pb->bio_submitted = true;
316
317 /*
318 * Error reads if neither corrupt_bio_byte or drop_writes or error_writes are set.
319 * Otherwise, flakey_end_io() will decide if the reads should be modified.
320 */
321 if (bio_data_dir(bio) == READ) {
322 if (!fc->corrupt_bio_byte && !test_bit(DROP_WRITES, &fc->flags) &&
323 !test_bit(ERROR_WRITES, &fc->flags))
324 return -EIO;
325 goto map_bio;
326 }
327
328 /*
329 * Drop or error writes?
330 */
331 if (test_bit(DROP_WRITES, &fc->flags)) {
332 bio_endio(bio);
333 return DM_MAPIO_SUBMITTED;
334 }
335 else if (test_bit(ERROR_WRITES, &fc->flags)) {
336 bio_io_error(bio);
337 return DM_MAPIO_SUBMITTED;
338 }
339
340 /*
341 * Corrupt matching writes.
342 */
343 if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == WRITE)) {
344 if (all_corrupt_bio_flags_match(bio, fc))
345 corrupt_bio_data(bio, fc);
346 goto map_bio;
347 }
348
349 /*
350 * By default, error all I/O.
351 */
352 return -EIO;
353 }
354
355map_bio:
356 flakey_map_bio(ti, bio);
357
358 return DM_MAPIO_REMAPPED;
359}
360
361static int flakey_end_io(struct dm_target *ti, struct bio *bio, int error)
362{
363 struct flakey_c *fc = ti->private;
364 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
365
366 if (!error && pb->bio_submitted && (bio_data_dir(bio) == READ)) {
367 if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == READ) &&
368 all_corrupt_bio_flags_match(bio, fc)) {
369 /*
370 * Corrupt successful matching READs while in down state.
371 */
372 corrupt_bio_data(bio, fc);
373
374 } else if (!test_bit(DROP_WRITES, &fc->flags) &&
375 !test_bit(ERROR_WRITES, &fc->flags)) {
376 /*
377 * Error read during the down_interval if drop_writes
378 * and error_writes were not configured.
379 */
380 return -EIO;
381 }
382 }
383
384 return error;
385}
386
387static void flakey_status(struct dm_target *ti, status_type_t type,
388 unsigned status_flags, char *result, unsigned maxlen)
389{
390 unsigned sz = 0;
391 struct flakey_c *fc = ti->private;
392 unsigned drop_writes, error_writes;
393
394 switch (type) {
395 case STATUSTYPE_INFO:
396 result[0] = '\0';
397 break;
398
399 case STATUSTYPE_TABLE:
400 DMEMIT("%s %llu %u %u ", fc->dev->name,
401 (unsigned long long)fc->start, fc->up_interval,
402 fc->down_interval);
403
404 drop_writes = test_bit(DROP_WRITES, &fc->flags);
405 error_writes = test_bit(ERROR_WRITES, &fc->flags);
406 DMEMIT("%u ", drop_writes + error_writes + (fc->corrupt_bio_byte > 0) * 5);
407
408 if (drop_writes)
409 DMEMIT("drop_writes ");
410 else if (error_writes)
411 DMEMIT("error_writes ");
412
413 if (fc->corrupt_bio_byte)
414 DMEMIT("corrupt_bio_byte %u %c %u %u ",
415 fc->corrupt_bio_byte,
416 (fc->corrupt_bio_rw == WRITE) ? 'w' : 'r',
417 fc->corrupt_bio_value, fc->corrupt_bio_flags);
418
419 break;
420 }
421}
422
423static int flakey_prepare_ioctl(struct dm_target *ti,
424 struct block_device **bdev, fmode_t *mode)
425{
426 struct flakey_c *fc = ti->private;
427
428 *bdev = fc->dev->bdev;
429
430 /*
431 * Only pass ioctls through if the device sizes match exactly.
432 */
433 if (fc->start ||
434 ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT)
435 return 1;
436 return 0;
437}
438
439static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
440{
441 struct flakey_c *fc = ti->private;
442
443 return fn(ti, fc->dev, fc->start, ti->len, data);
444}
445
446static struct target_type flakey_target = {
447 .name = "flakey",
448 .version = {1, 4, 0},
449 .module = THIS_MODULE,
450 .ctr = flakey_ctr,
451 .dtr = flakey_dtr,
452 .map = flakey_map,
453 .end_io = flakey_end_io,
454 .status = flakey_status,
455 .prepare_ioctl = flakey_prepare_ioctl,
456 .iterate_devices = flakey_iterate_devices,
457};
458
459static int __init dm_flakey_init(void)
460{
461 int r = dm_register_target(&flakey_target);
462
463 if (r < 0)
464 DMERR("register failed %d", r);
465
466 return r;
467}
468
469static void __exit dm_flakey_exit(void)
470{
471 dm_unregister_target(&flakey_target);
472}
473
474/* Module hooks */
475module_init(dm_flakey_init);
476module_exit(dm_flakey_exit);
477
478MODULE_DESCRIPTION(DM_NAME " flakey target");
479MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
480MODULE_LICENSE("GPL");