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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * faulty.c : Multiple Devices driver for Linux
4 *
5 * Copyright (C) 2004 Neil Brown
6 *
7 * fautly-device-simulator personality for md
8 */
9
10
11/*
12 * The "faulty" personality causes some requests to fail.
13 *
14 * Possible failure modes are:
15 * reads fail "randomly" but succeed on retry
16 * writes fail "randomly" but succeed on retry
17 * reads for some address fail and then persist until a write
18 * reads for some address fail and then persist irrespective of write
19 * writes for some address fail and persist
20 * all writes fail
21 *
22 * Different modes can be active at a time, but only
23 * one can be set at array creation. Others can be added later.
24 * A mode can be one-shot or recurrent with the recurrence being
25 * once in every N requests.
26 * The bottom 5 bits of the "layout" indicate the mode. The
27 * remainder indicate a period, or 0 for one-shot.
28 *
29 * There is an implementation limit on the number of concurrently
30 * persisting-faulty blocks. When a new fault is requested that would
31 * exceed the limit, it is ignored.
32 * All current faults can be clear using a layout of "0".
33 *
34 * Requests are always sent to the device. If they are to fail,
35 * we clone the bio and insert a new b_end_io into the chain.
36 */
37
38#define WriteTransient 0
39#define ReadTransient 1
40#define WritePersistent 2
41#define ReadPersistent 3
42#define WriteAll 4 /* doesn't go to device */
43#define ReadFixable 5
44#define Modes 6
45
46#define ClearErrors 31
47#define ClearFaults 30
48
49#define AllPersist 100 /* internal use only */
50#define NoPersist 101
51
52#define ModeMask 0x1f
53#define ModeShift 5
54
55#define MaxFault 50
56#include <linux/blkdev.h>
57#include <linux/module.h>
58#include <linux/raid/md_u.h>
59#include <linux/slab.h>
60#include "md.h"
61#include <linux/seq_file.h>
62
63
64static void faulty_fail(struct bio *bio)
65{
66 struct bio *b = bio->bi_private;
67
68 b->bi_iter.bi_size = bio->bi_iter.bi_size;
69 b->bi_iter.bi_sector = bio->bi_iter.bi_sector;
70
71 bio_put(bio);
72
73 bio_io_error(b);
74}
75
76struct faulty_conf {
77 int period[Modes];
78 atomic_t counters[Modes];
79 sector_t faults[MaxFault];
80 int modes[MaxFault];
81 int nfaults;
82 struct md_rdev *rdev;
83};
84
85static int check_mode(struct faulty_conf *conf, int mode)
86{
87 if (conf->period[mode] == 0 &&
88 atomic_read(&conf->counters[mode]) <= 0)
89 return 0; /* no failure, no decrement */
90
91
92 if (atomic_dec_and_test(&conf->counters[mode])) {
93 if (conf->period[mode])
94 atomic_set(&conf->counters[mode], conf->period[mode]);
95 return 1;
96 }
97 return 0;
98}
99
100static int check_sector(struct faulty_conf *conf, sector_t start, sector_t end, int dir)
101{
102 /* If we find a ReadFixable sector, we fix it ... */
103 int i;
104 for (i=0; i<conf->nfaults; i++)
105 if (conf->faults[i] >= start &&
106 conf->faults[i] < end) {
107 /* found it ... */
108 switch (conf->modes[i] * 2 + dir) {
109 case WritePersistent*2+WRITE: return 1;
110 case ReadPersistent*2+READ: return 1;
111 case ReadFixable*2+READ: return 1;
112 case ReadFixable*2+WRITE:
113 conf->modes[i] = NoPersist;
114 return 0;
115 case AllPersist*2+READ:
116 case AllPersist*2+WRITE: return 1;
117 default:
118 return 0;
119 }
120 }
121 return 0;
122}
123
124static void add_sector(struct faulty_conf *conf, sector_t start, int mode)
125{
126 int i;
127 int n = conf->nfaults;
128 for (i=0; i<conf->nfaults; i++)
129 if (conf->faults[i] == start) {
130 switch(mode) {
131 case NoPersist: conf->modes[i] = mode; return;
132 case WritePersistent:
133 if (conf->modes[i] == ReadPersistent ||
134 conf->modes[i] == ReadFixable)
135 conf->modes[i] = AllPersist;
136 else
137 conf->modes[i] = WritePersistent;
138 return;
139 case ReadPersistent:
140 if (conf->modes[i] == WritePersistent)
141 conf->modes[i] = AllPersist;
142 else
143 conf->modes[i] = ReadPersistent;
144 return;
145 case ReadFixable:
146 if (conf->modes[i] == WritePersistent ||
147 conf->modes[i] == ReadPersistent)
148 conf->modes[i] = AllPersist;
149 else
150 conf->modes[i] = ReadFixable;
151 return;
152 }
153 } else if (conf->modes[i] == NoPersist)
154 n = i;
155
156 if (n >= MaxFault)
157 return;
158 conf->faults[n] = start;
159 conf->modes[n] = mode;
160 if (conf->nfaults == n)
161 conf->nfaults = n+1;
162}
163
164static bool faulty_make_request(struct mddev *mddev, struct bio *bio)
165{
166 struct faulty_conf *conf = mddev->private;
167 int failit = 0;
168
169 if (bio_data_dir(bio) == WRITE) {
170 /* write request */
171 if (atomic_read(&conf->counters[WriteAll])) {
172 /* special case - don't decrement, don't submit_bio_noacct,
173 * just fail immediately
174 */
175 bio_io_error(bio);
176 return true;
177 }
178
179 if (check_sector(conf, bio->bi_iter.bi_sector,
180 bio_end_sector(bio), WRITE))
181 failit = 1;
182 if (check_mode(conf, WritePersistent)) {
183 add_sector(conf, bio->bi_iter.bi_sector,
184 WritePersistent);
185 failit = 1;
186 }
187 if (check_mode(conf, WriteTransient))
188 failit = 1;
189 } else {
190 /* read request */
191 if (check_sector(conf, bio->bi_iter.bi_sector,
192 bio_end_sector(bio), READ))
193 failit = 1;
194 if (check_mode(conf, ReadTransient))
195 failit = 1;
196 if (check_mode(conf, ReadPersistent)) {
197 add_sector(conf, bio->bi_iter.bi_sector,
198 ReadPersistent);
199 failit = 1;
200 }
201 if (check_mode(conf, ReadFixable)) {
202 add_sector(conf, bio->bi_iter.bi_sector,
203 ReadFixable);
204 failit = 1;
205 }
206 }
207 if (failit) {
208 struct bio *b = bio_alloc_clone(conf->rdev->bdev, bio, GFP_NOIO,
209 &mddev->bio_set);
210
211 b->bi_private = bio;
212 b->bi_end_io = faulty_fail;
213 bio = b;
214 } else
215 bio_set_dev(bio, conf->rdev->bdev);
216
217 submit_bio_noacct(bio);
218 return true;
219}
220
221static void faulty_status(struct seq_file *seq, struct mddev *mddev)
222{
223 struct faulty_conf *conf = mddev->private;
224 int n;
225
226 if ((n=atomic_read(&conf->counters[WriteTransient])) != 0)
227 seq_printf(seq, " WriteTransient=%d(%d)",
228 n, conf->period[WriteTransient]);
229
230 if ((n=atomic_read(&conf->counters[ReadTransient])) != 0)
231 seq_printf(seq, " ReadTransient=%d(%d)",
232 n, conf->period[ReadTransient]);
233
234 if ((n=atomic_read(&conf->counters[WritePersistent])) != 0)
235 seq_printf(seq, " WritePersistent=%d(%d)",
236 n, conf->period[WritePersistent]);
237
238 if ((n=atomic_read(&conf->counters[ReadPersistent])) != 0)
239 seq_printf(seq, " ReadPersistent=%d(%d)",
240 n, conf->period[ReadPersistent]);
241
242
243 if ((n=atomic_read(&conf->counters[ReadFixable])) != 0)
244 seq_printf(seq, " ReadFixable=%d(%d)",
245 n, conf->period[ReadFixable]);
246
247 if ((n=atomic_read(&conf->counters[WriteAll])) != 0)
248 seq_printf(seq, " WriteAll");
249
250 seq_printf(seq, " nfaults=%d", conf->nfaults);
251}
252
253
254static int faulty_reshape(struct mddev *mddev)
255{
256 int mode = mddev->new_layout & ModeMask;
257 int count = mddev->new_layout >> ModeShift;
258 struct faulty_conf *conf = mddev->private;
259
260 if (mddev->new_layout < 0)
261 return 0;
262
263 /* new layout */
264 if (mode == ClearFaults)
265 conf->nfaults = 0;
266 else if (mode == ClearErrors) {
267 int i;
268 for (i=0 ; i < Modes ; i++) {
269 conf->period[i] = 0;
270 atomic_set(&conf->counters[i], 0);
271 }
272 } else if (mode < Modes) {
273 conf->period[mode] = count;
274 if (!count) count++;
275 atomic_set(&conf->counters[mode], count);
276 } else
277 return -EINVAL;
278 mddev->new_layout = -1;
279 mddev->layout = -1; /* makes sure further changes come through */
280 return 0;
281}
282
283static sector_t faulty_size(struct mddev *mddev, sector_t sectors, int raid_disks)
284{
285 WARN_ONCE(raid_disks,
286 "%s does not support generic reshape\n", __func__);
287
288 if (sectors == 0)
289 return mddev->dev_sectors;
290
291 return sectors;
292}
293
294static int faulty_run(struct mddev *mddev)
295{
296 struct md_rdev *rdev;
297 int i;
298 struct faulty_conf *conf;
299
300 if (md_check_no_bitmap(mddev))
301 return -EINVAL;
302
303 conf = kmalloc(sizeof(*conf), GFP_KERNEL);
304 if (!conf)
305 return -ENOMEM;
306
307 for (i=0; i<Modes; i++) {
308 atomic_set(&conf->counters[i], 0);
309 conf->period[i] = 0;
310 }
311 conf->nfaults = 0;
312
313 rdev_for_each(rdev, mddev) {
314 conf->rdev = rdev;
315 disk_stack_limits(mddev->gendisk, rdev->bdev,
316 rdev->data_offset << 9);
317 }
318
319 md_set_array_sectors(mddev, faulty_size(mddev, 0, 0));
320 mddev->private = conf;
321
322 faulty_reshape(mddev);
323
324 return 0;
325}
326
327static void faulty_free(struct mddev *mddev, void *priv)
328{
329 struct faulty_conf *conf = priv;
330
331 kfree(conf);
332}
333
334static struct md_personality faulty_personality =
335{
336 .name = "faulty",
337 .level = LEVEL_FAULTY,
338 .owner = THIS_MODULE,
339 .make_request = faulty_make_request,
340 .run = faulty_run,
341 .free = faulty_free,
342 .status = faulty_status,
343 .check_reshape = faulty_reshape,
344 .size = faulty_size,
345};
346
347static int __init raid_init(void)
348{
349 return register_md_personality(&faulty_personality);
350}
351
352static void raid_exit(void)
353{
354 unregister_md_personality(&faulty_personality);
355}
356
357module_init(raid_init);
358module_exit(raid_exit);
359MODULE_LICENSE("GPL");
360MODULE_DESCRIPTION("Fault injection personality for MD (deprecated)");
361MODULE_ALIAS("md-personality-10"); /* faulty */
362MODULE_ALIAS("md-faulty");
363MODULE_ALIAS("md-level--5");
1/*
2 * faulty.c : Multiple Devices driver for Linux
3 *
4 * Copyright (C) 2004 Neil Brown
5 *
6 * fautly-device-simulator personality for md
7 *
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2, or (at your option)
12 * any later version.
13 *
14 * You should have received a copy of the GNU General Public License
15 * (for example /usr/src/linux/COPYING); if not, write to the Free
16 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19
20/*
21 * The "faulty" personality causes some requests to fail.
22 *
23 * Possible failure modes are:
24 * reads fail "randomly" but succeed on retry
25 * writes fail "randomly" but succeed on retry
26 * reads for some address fail and then persist until a write
27 * reads for some address fail and then persist irrespective of write
28 * writes for some address fail and persist
29 * all writes fail
30 *
31 * Different modes can be active at a time, but only
32 * one can be set at array creation. Others can be added later.
33 * A mode can be one-shot or recurrent with the recurrence being
34 * once in every N requests.
35 * The bottom 5 bits of the "layout" indicate the mode. The
36 * remainder indicate a period, or 0 for one-shot.
37 *
38 * There is an implementation limit on the number of concurrently
39 * persisting-faulty blocks. When a new fault is requested that would
40 * exceed the limit, it is ignored.
41 * All current faults can be clear using a layout of "0".
42 *
43 * Requests are always sent to the device. If they are to fail,
44 * we clone the bio and insert a new b_end_io into the chain.
45 */
46
47#define WriteTransient 0
48#define ReadTransient 1
49#define WritePersistent 2
50#define ReadPersistent 3
51#define WriteAll 4 /* doesn't go to device */
52#define ReadFixable 5
53#define Modes 6
54
55#define ClearErrors 31
56#define ClearFaults 30
57
58#define AllPersist 100 /* internal use only */
59#define NoPersist 101
60
61#define ModeMask 0x1f
62#define ModeShift 5
63
64#define MaxFault 50
65#include <linux/blkdev.h>
66#include <linux/module.h>
67#include <linux/raid/md_u.h>
68#include <linux/slab.h>
69#include "md.h"
70#include <linux/seq_file.h>
71
72
73static void faulty_fail(struct bio *bio)
74{
75 struct bio *b = bio->bi_private;
76
77 b->bi_iter.bi_size = bio->bi_iter.bi_size;
78 b->bi_iter.bi_sector = bio->bi_iter.bi_sector;
79
80 bio_put(bio);
81
82 bio_io_error(b);
83}
84
85struct faulty_conf {
86 int period[Modes];
87 atomic_t counters[Modes];
88 sector_t faults[MaxFault];
89 int modes[MaxFault];
90 int nfaults;
91 struct md_rdev *rdev;
92};
93
94static int check_mode(struct faulty_conf *conf, int mode)
95{
96 if (conf->period[mode] == 0 &&
97 atomic_read(&conf->counters[mode]) <= 0)
98 return 0; /* no failure, no decrement */
99
100
101 if (atomic_dec_and_test(&conf->counters[mode])) {
102 if (conf->period[mode])
103 atomic_set(&conf->counters[mode], conf->period[mode]);
104 return 1;
105 }
106 return 0;
107}
108
109static int check_sector(struct faulty_conf *conf, sector_t start, sector_t end, int dir)
110{
111 /* If we find a ReadFixable sector, we fix it ... */
112 int i;
113 for (i=0; i<conf->nfaults; i++)
114 if (conf->faults[i] >= start &&
115 conf->faults[i] < end) {
116 /* found it ... */
117 switch (conf->modes[i] * 2 + dir) {
118 case WritePersistent*2+WRITE: return 1;
119 case ReadPersistent*2+READ: return 1;
120 case ReadFixable*2+READ: return 1;
121 case ReadFixable*2+WRITE:
122 conf->modes[i] = NoPersist;
123 return 0;
124 case AllPersist*2+READ:
125 case AllPersist*2+WRITE: return 1;
126 default:
127 return 0;
128 }
129 }
130 return 0;
131}
132
133static void add_sector(struct faulty_conf *conf, sector_t start, int mode)
134{
135 int i;
136 int n = conf->nfaults;
137 for (i=0; i<conf->nfaults; i++)
138 if (conf->faults[i] == start) {
139 switch(mode) {
140 case NoPersist: conf->modes[i] = mode; return;
141 case WritePersistent:
142 if (conf->modes[i] == ReadPersistent ||
143 conf->modes[i] == ReadFixable)
144 conf->modes[i] = AllPersist;
145 else
146 conf->modes[i] = WritePersistent;
147 return;
148 case ReadPersistent:
149 if (conf->modes[i] == WritePersistent)
150 conf->modes[i] = AllPersist;
151 else
152 conf->modes[i] = ReadPersistent;
153 return;
154 case ReadFixable:
155 if (conf->modes[i] == WritePersistent ||
156 conf->modes[i] == ReadPersistent)
157 conf->modes[i] = AllPersist;
158 else
159 conf->modes[i] = ReadFixable;
160 return;
161 }
162 } else if (conf->modes[i] == NoPersist)
163 n = i;
164
165 if (n >= MaxFault)
166 return;
167 conf->faults[n] = start;
168 conf->modes[n] = mode;
169 if (conf->nfaults == n)
170 conf->nfaults = n+1;
171}
172
173static bool faulty_make_request(struct mddev *mddev, struct bio *bio)
174{
175 struct faulty_conf *conf = mddev->private;
176 int failit = 0;
177
178 if (bio_data_dir(bio) == WRITE) {
179 /* write request */
180 if (atomic_read(&conf->counters[WriteAll])) {
181 /* special case - don't decrement, don't generic_make_request,
182 * just fail immediately
183 */
184 bio_io_error(bio);
185 return true;
186 }
187
188 if (check_sector(conf, bio->bi_iter.bi_sector,
189 bio_end_sector(bio), WRITE))
190 failit = 1;
191 if (check_mode(conf, WritePersistent)) {
192 add_sector(conf, bio->bi_iter.bi_sector,
193 WritePersistent);
194 failit = 1;
195 }
196 if (check_mode(conf, WriteTransient))
197 failit = 1;
198 } else {
199 /* read request */
200 if (check_sector(conf, bio->bi_iter.bi_sector,
201 bio_end_sector(bio), READ))
202 failit = 1;
203 if (check_mode(conf, ReadTransient))
204 failit = 1;
205 if (check_mode(conf, ReadPersistent)) {
206 add_sector(conf, bio->bi_iter.bi_sector,
207 ReadPersistent);
208 failit = 1;
209 }
210 if (check_mode(conf, ReadFixable)) {
211 add_sector(conf, bio->bi_iter.bi_sector,
212 ReadFixable);
213 failit = 1;
214 }
215 }
216 if (failit) {
217 struct bio *b = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set);
218
219 bio_set_dev(b, conf->rdev->bdev);
220 b->bi_private = bio;
221 b->bi_end_io = faulty_fail;
222 bio = b;
223 } else
224 bio_set_dev(bio, conf->rdev->bdev);
225
226 generic_make_request(bio);
227 return true;
228}
229
230static void faulty_status(struct seq_file *seq, struct mddev *mddev)
231{
232 struct faulty_conf *conf = mddev->private;
233 int n;
234
235 if ((n=atomic_read(&conf->counters[WriteTransient])) != 0)
236 seq_printf(seq, " WriteTransient=%d(%d)",
237 n, conf->period[WriteTransient]);
238
239 if ((n=atomic_read(&conf->counters[ReadTransient])) != 0)
240 seq_printf(seq, " ReadTransient=%d(%d)",
241 n, conf->period[ReadTransient]);
242
243 if ((n=atomic_read(&conf->counters[WritePersistent])) != 0)
244 seq_printf(seq, " WritePersistent=%d(%d)",
245 n, conf->period[WritePersistent]);
246
247 if ((n=atomic_read(&conf->counters[ReadPersistent])) != 0)
248 seq_printf(seq, " ReadPersistent=%d(%d)",
249 n, conf->period[ReadPersistent]);
250
251
252 if ((n=atomic_read(&conf->counters[ReadFixable])) != 0)
253 seq_printf(seq, " ReadFixable=%d(%d)",
254 n, conf->period[ReadFixable]);
255
256 if ((n=atomic_read(&conf->counters[WriteAll])) != 0)
257 seq_printf(seq, " WriteAll");
258
259 seq_printf(seq, " nfaults=%d", conf->nfaults);
260}
261
262
263static int faulty_reshape(struct mddev *mddev)
264{
265 int mode = mddev->new_layout & ModeMask;
266 int count = mddev->new_layout >> ModeShift;
267 struct faulty_conf *conf = mddev->private;
268
269 if (mddev->new_layout < 0)
270 return 0;
271
272 /* new layout */
273 if (mode == ClearFaults)
274 conf->nfaults = 0;
275 else if (mode == ClearErrors) {
276 int i;
277 for (i=0 ; i < Modes ; i++) {
278 conf->period[i] = 0;
279 atomic_set(&conf->counters[i], 0);
280 }
281 } else if (mode < Modes) {
282 conf->period[mode] = count;
283 if (!count) count++;
284 atomic_set(&conf->counters[mode], count);
285 } else
286 return -EINVAL;
287 mddev->new_layout = -1;
288 mddev->layout = -1; /* makes sure further changes come through */
289 return 0;
290}
291
292static sector_t faulty_size(struct mddev *mddev, sector_t sectors, int raid_disks)
293{
294 WARN_ONCE(raid_disks,
295 "%s does not support generic reshape\n", __func__);
296
297 if (sectors == 0)
298 return mddev->dev_sectors;
299
300 return sectors;
301}
302
303static int faulty_run(struct mddev *mddev)
304{
305 struct md_rdev *rdev;
306 int i;
307 struct faulty_conf *conf;
308
309 if (md_check_no_bitmap(mddev))
310 return -EINVAL;
311
312 conf = kmalloc(sizeof(*conf), GFP_KERNEL);
313 if (!conf)
314 return -ENOMEM;
315
316 for (i=0; i<Modes; i++) {
317 atomic_set(&conf->counters[i], 0);
318 conf->period[i] = 0;
319 }
320 conf->nfaults = 0;
321
322 rdev_for_each(rdev, mddev) {
323 conf->rdev = rdev;
324 disk_stack_limits(mddev->gendisk, rdev->bdev,
325 rdev->data_offset << 9);
326 }
327
328 md_set_array_sectors(mddev, faulty_size(mddev, 0, 0));
329 mddev->private = conf;
330
331 faulty_reshape(mddev);
332
333 return 0;
334}
335
336static void faulty_free(struct mddev *mddev, void *priv)
337{
338 struct faulty_conf *conf = priv;
339
340 kfree(conf);
341}
342
343static struct md_personality faulty_personality =
344{
345 .name = "faulty",
346 .level = LEVEL_FAULTY,
347 .owner = THIS_MODULE,
348 .make_request = faulty_make_request,
349 .run = faulty_run,
350 .free = faulty_free,
351 .status = faulty_status,
352 .check_reshape = faulty_reshape,
353 .size = faulty_size,
354};
355
356static int __init raid_init(void)
357{
358 return register_md_personality(&faulty_personality);
359}
360
361static void raid_exit(void)
362{
363 unregister_md_personality(&faulty_personality);
364}
365
366module_init(raid_init);
367module_exit(raid_exit);
368MODULE_LICENSE("GPL");
369MODULE_DESCRIPTION("Fault injection personality for MD");
370MODULE_ALIAS("md-personality-10"); /* faulty */
371MODULE_ALIAS("md-faulty");
372MODULE_ALIAS("md-level--5");