watchdog: pic32-dmt: Remove .owner field for driver
[linux/fpc-iii.git] / drivers / md / dm-flakey.c
blobb7341de87015e774c30e93324c5e05560b7f6c3f
1 /*
2 * Copyright (C) 2003 Sistina Software (UK) Limited.
3 * Copyright (C) 2004, 2010-2011 Red Hat, Inc. All rights reserved.
5 * This file is released under the GPL.
6 */
8 #include <linux/device-mapper.h>
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>
16 #define DM_MSG_PREFIX "flakey"
18 #define all_corrupt_bio_flags_match(bio, fc) \
19 (((bio)->bi_rw & (fc)->corrupt_bio_flags) == (fc)->corrupt_bio_flags)
22 * Flakey: Used for testing only, simulates intermittent,
23 * catastrophic device failure.
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;
31 unsigned long flags;
32 unsigned corrupt_bio_byte;
33 unsigned corrupt_bio_rw;
34 unsigned corrupt_bio_value;
35 unsigned corrupt_bio_flags;
38 enum feature_flag_bits {
39 DROP_WRITES
42 struct per_bio_data {
43 bool bio_submitted;
46 static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
47 struct dm_target *ti)
49 int r;
50 unsigned argc;
51 const char *arg_name;
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"},
60 /* No feature arguments supplied. */
61 if (!as->argc)
62 return 0;
64 r = dm_read_arg_group(_args, as, &argc, &ti->error);
65 if (r)
66 return r;
68 while (argc) {
69 arg_name = dm_shift_arg(as);
70 argc--;
73 * drop_writes
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;
81 continue;
85 * corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>
87 if (!strcasecmp(arg_name, "corrupt_bio_byte")) {
88 if (!argc) {
89 ti->error = "Feature corrupt_bio_byte requires parameters";
90 return -EINVAL;
93 r = dm_read_arg(_args + 1, as, &fc->corrupt_bio_byte, &ti->error);
94 if (r)
95 return r;
96 argc--;
99 * Direction r or w?
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;
110 argc--;
113 * Value of byte (0-255) to write in place of correct one.
115 r = dm_read_arg(_args + 2, as, &fc->corrupt_bio_value, &ti->error);
116 if (r)
117 return r;
118 argc--;
121 * Only corrupt bios with these flags set.
123 r = dm_read_arg(_args + 3, as, &fc->corrupt_bio_flags, &ti->error);
124 if (r)
125 return r;
126 argc--;
128 continue;
131 ti->error = "Unrecognised flakey feature requested";
132 return -EINVAL;
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;
140 return 0;
144 * Construct a flakey mapping:
145 * <dev_path> <offset> <up interval> <down interval> [<#feature args> [<arg>]*]
147 * Feature args:
148 * [drop_writes]
149 * [corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>]
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.
155 static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv)
157 static struct dm_arg _args[] = {
158 {0, UINT_MAX, "Invalid up interval"},
159 {0, UINT_MAX, "Invalid down interval"},
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;
169 as.argc = argc;
170 as.argv = argv;
172 if (argc < 4) {
173 ti->error = "Invalid argument count";
174 return -EINVAL;
177 fc = kzalloc(sizeof(*fc), GFP_KERNEL);
178 if (!fc) {
179 ti->error = "Cannot allocate context";
180 return -ENOMEM;
182 fc->start_time = jiffies;
184 devname = dm_shift_arg(&as);
186 r = -EINVAL;
187 if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1) {
188 ti->error = "Invalid device sector";
189 goto bad;
191 fc->start = tmpll;
193 r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
194 if (r)
195 goto bad;
197 r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
198 if (r)
199 goto bad;
201 if (!(fc->up_interval + fc->down_interval)) {
202 ti->error = "Total (up + down) interval is zero";
203 goto bad;
206 if (fc->up_interval + fc->down_interval < fc->up_interval) {
207 ti->error = "Interval overflow";
208 goto bad;
211 r = parse_features(&as, fc, ti);
212 if (r)
213 goto bad;
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;
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;
227 bad:
228 kfree(fc);
229 return r;
232 static void flakey_dtr(struct dm_target *ti)
234 struct flakey_c *fc = ti->private;
236 dm_put_device(ti, fc->dev);
237 kfree(fc);
240 static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector)
242 struct flakey_c *fc = ti->private;
244 return fc->start + dm_target_offset(ti, bi_sector);
247 static void flakey_map_bio(struct dm_target *ti, struct bio *bio)
249 struct flakey_c *fc = ti->private;
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);
257 static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc)
259 unsigned bio_bytes = bio_cur_bytes(bio);
260 char *data = bio_data(bio);
263 * Overwrite the Nth byte of the data returned.
265 if (data && bio_bytes >= fc->corrupt_bio_byte) {
266 data[fc->corrupt_bio_byte - 1] = fc->corrupt_bio_value;
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);
276 static int flakey_map(struct dm_target *ti, struct bio *bio)
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;
283 /* Are we alive ? */
284 elapsed = (jiffies - fc->start_time) / HZ;
285 if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
287 * Flag this bio as submitted while down.
289 pb->bio_submitted = true;
292 * Map reads as normal.
294 if (bio_data_dir(bio) == READ)
295 goto map_bio;
298 * Drop writes?
300 if (test_bit(DROP_WRITES, &fc->flags)) {
301 bio_endio(bio);
302 return DM_MAPIO_SUBMITTED;
306 * Corrupt matching writes.
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;
315 * By default, error all I/O.
317 return -EIO;
320 map_bio:
321 flakey_map_bio(ti, bio);
323 return DM_MAPIO_REMAPPED;
326 static int flakey_end_io(struct dm_target *ti, struct bio *bio, int error)
328 struct flakey_c *fc = ti->private;
329 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
332 * Corrupt successful READs while in down state.
333 * If flags were specified, only corrupt those that match.
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);
340 return error;
343 static void flakey_status(struct dm_target *ti, status_type_t type,
344 unsigned status_flags, char *result, unsigned maxlen)
346 unsigned sz = 0;
347 struct flakey_c *fc = ti->private;
348 unsigned drop_writes;
350 switch (type) {
351 case STATUSTYPE_INFO:
352 result[0] = '\0';
353 break;
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);
360 drop_writes = test_bit(DROP_WRITES, &fc->flags);
361 DMEMIT("%u ", drop_writes + (fc->corrupt_bio_byte > 0) * 5);
363 if (drop_writes)
364 DMEMIT("drop_writes ");
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);
372 break;
376 static int flakey_prepare_ioctl(struct dm_target *ti,
377 struct block_device **bdev, fmode_t *mode)
379 struct flakey_c *fc = ti->private;
381 *bdev = fc->dev->bdev;
384 * Only pass ioctls through if the device sizes match exactly.
386 if (fc->start ||
387 ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT)
388 return 1;
389 return 0;
392 static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
394 struct flakey_c *fc = ti->private;
396 return fn(ti, fc->dev, fc->start, ti->len, data);
399 static 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,
412 static int __init dm_flakey_init(void)
414 int r = dm_register_target(&flakey_target);
416 if (r < 0)
417 DMERR("register failed %d", r);
419 return r;
422 static void __exit dm_flakey_exit(void)
424 dm_unregister_target(&flakey_target);
427 /* Module hooks */
428 module_init(dm_flakey_init);
429 module_exit(dm_flakey_exit);
431 MODULE_DESCRIPTION(DM_NAME " flakey target");
432 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
433 MODULE_LICENSE("GPL");