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.
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_opf & (fc)->corrupt_bio_flags) == (fc)->corrupt_bio_flags)
22 * Flakey: Used for testing only, simulates intermittent,
23 * catastrophic device failure.
27 unsigned long start_time;
30 unsigned down_interval;
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 {
47 static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
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"},
61 /* No feature arguments supplied. */
65 r = dm_read_arg_group(_args, as, &argc, &ti->error);
70 arg_name = dm_shift_arg(as);
74 ti->error = "Insufficient feature arguments";
81 if (!strcasecmp(arg_name, "drop_writes")) {
82 if (test_and_set_bit(DROP_WRITES, &fc->flags)) {
83 ti->error = "Feature drop_writes duplicated";
85 } else if (test_bit(ERROR_WRITES, &fc->flags)) {
86 ti->error = "Feature drop_writes conflicts with feature error_writes";
96 if (!strcasecmp(arg_name, "error_writes")) {
97 if (test_and_set_bit(ERROR_WRITES, &fc->flags)) {
98 ti->error = "Feature error_writes duplicated";
101 } else if (test_bit(DROP_WRITES, &fc->flags)) {
102 ti->error = "Feature error_writes conflicts with feature drop_writes";
110 * corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>
112 if (!strcasecmp(arg_name, "corrupt_bio_byte")) {
114 ti->error = "Feature corrupt_bio_byte requires parameters";
118 r = dm_read_arg(_args + 1, as, &fc->corrupt_bio_byte, &ti->error);
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;
132 ti->error = "Invalid corrupt bio direction (r or w)";
138 * Value of byte (0-255) to write in place of correct one.
140 r = dm_read_arg(_args + 2, as, &fc->corrupt_bio_value, &ti->error);
146 * Only corrupt bios with these flags set.
148 r = dm_read_arg(_args + 3, as, &fc->corrupt_bio_flags, &ti->error);
156 ti->error = "Unrecognised flakey feature requested";
160 if (test_bit(DROP_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) {
161 ti->error = "drop_writes is incompatible with corrupt_bio_byte with the WRITE flag set";
164 } else if (test_bit(ERROR_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) {
165 ti->error = "error_writes is incompatible with corrupt_bio_byte with the WRITE flag set";
173 * Construct a flakey mapping:
174 * <dev_path> <offset> <up interval> <down interval> [<#feature args> [<arg>]*]
178 * [corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>]
180 * Nth_byte starts from 1 for the first byte.
181 * Direction is r for READ or w for WRITE.
182 * bio_flags is ignored if 0.
184 static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv)
186 static const struct dm_arg _args[] = {
187 {0, UINT_MAX, "Invalid up interval"},
188 {0, UINT_MAX, "Invalid down interval"},
193 unsigned long long tmpll;
194 struct dm_arg_set as;
202 ti->error = "Invalid argument count";
206 fc = kzalloc(sizeof(*fc), GFP_KERNEL);
208 ti->error = "Cannot allocate context";
211 fc->start_time = jiffies;
213 devname = dm_shift_arg(&as);
216 if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1) {
217 ti->error = "Invalid device sector";
222 r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
226 r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
230 if (!(fc->up_interval + fc->down_interval)) {
231 ti->error = "Total (up + down) interval is zero";
236 if (fc->up_interval + fc->down_interval < fc->up_interval) {
237 ti->error = "Interval overflow";
242 r = parse_features(&as, fc, ti);
246 r = dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev);
248 ti->error = "Device lookup failed";
252 ti->num_flush_bios = 1;
253 ti->num_discard_bios = 1;
254 ti->per_io_data_size = sizeof(struct per_bio_data);
263 static void flakey_dtr(struct dm_target *ti)
265 struct flakey_c *fc = ti->private;
267 dm_put_device(ti, fc->dev);
271 static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector)
273 struct flakey_c *fc = ti->private;
275 return fc->start + dm_target_offset(ti, bi_sector);
278 static void flakey_map_bio(struct dm_target *ti, struct bio *bio)
280 struct flakey_c *fc = ti->private;
282 bio_set_dev(bio, fc->dev->bdev);
283 if (bio_sectors(bio) || bio_op(bio) == REQ_OP_ZONE_RESET)
284 bio->bi_iter.bi_sector =
285 flakey_map_sector(ti, bio->bi_iter.bi_sector);
288 static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc)
290 unsigned bio_bytes = bio_cur_bytes(bio);
291 char *data = bio_data(bio);
294 * Overwrite the Nth byte of the data returned.
296 if (data && bio_bytes >= fc->corrupt_bio_byte) {
297 data[fc->corrupt_bio_byte - 1] = fc->corrupt_bio_value;
299 DMDEBUG("Corrupting data bio=%p by writing %u to byte %u "
300 "(rw=%c bi_opf=%u bi_sector=%llu cur_bytes=%u)\n",
301 bio, fc->corrupt_bio_value, fc->corrupt_bio_byte,
302 (bio_data_dir(bio) == WRITE) ? 'w' : 'r', bio->bi_opf,
303 (unsigned long long)bio->bi_iter.bi_sector, bio_bytes);
307 static int flakey_map(struct dm_target *ti, struct bio *bio)
309 struct flakey_c *fc = ti->private;
311 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
312 pb->bio_submitted = false;
314 /* Do not fail reset zone */
315 if (bio_op(bio) == REQ_OP_ZONE_RESET)
319 elapsed = (jiffies - fc->start_time) / HZ;
320 if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
322 * Flag this bio as submitted while down.
324 pb->bio_submitted = true;
327 * Error reads if neither corrupt_bio_byte or drop_writes or error_writes are set.
328 * Otherwise, flakey_end_io() will decide if the reads should be modified.
330 if (bio_data_dir(bio) == READ) {
331 if (!fc->corrupt_bio_byte && !test_bit(DROP_WRITES, &fc->flags) &&
332 !test_bit(ERROR_WRITES, &fc->flags))
333 return DM_MAPIO_KILL;
338 * Drop or error writes?
340 if (test_bit(DROP_WRITES, &fc->flags)) {
342 return DM_MAPIO_SUBMITTED;
344 else if (test_bit(ERROR_WRITES, &fc->flags)) {
346 return DM_MAPIO_SUBMITTED;
350 * Corrupt matching writes.
352 if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == WRITE)) {
353 if (all_corrupt_bio_flags_match(bio, fc))
354 corrupt_bio_data(bio, fc);
359 * By default, error all I/O.
361 return DM_MAPIO_KILL;
365 flakey_map_bio(ti, bio);
367 return DM_MAPIO_REMAPPED;
370 static int flakey_end_io(struct dm_target *ti, struct bio *bio,
373 struct flakey_c *fc = ti->private;
374 struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
376 if (bio_op(bio) == REQ_OP_ZONE_RESET)
377 return DM_ENDIO_DONE;
379 if (!*error && pb->bio_submitted && (bio_data_dir(bio) == READ)) {
380 if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == READ) &&
381 all_corrupt_bio_flags_match(bio, fc)) {
383 * Corrupt successful matching READs while in down state.
385 corrupt_bio_data(bio, fc);
387 } else if (!test_bit(DROP_WRITES, &fc->flags) &&
388 !test_bit(ERROR_WRITES, &fc->flags)) {
390 * Error read during the down_interval if drop_writes
391 * and error_writes were not configured.
393 *error = BLK_STS_IOERR;
397 return DM_ENDIO_DONE;
400 static void flakey_status(struct dm_target *ti, status_type_t type,
401 unsigned status_flags, char *result, unsigned maxlen)
404 struct flakey_c *fc = ti->private;
405 unsigned drop_writes, error_writes;
408 case STATUSTYPE_INFO:
412 case STATUSTYPE_TABLE:
413 DMEMIT("%s %llu %u %u ", fc->dev->name,
414 (unsigned long long)fc->start, fc->up_interval,
417 drop_writes = test_bit(DROP_WRITES, &fc->flags);
418 error_writes = test_bit(ERROR_WRITES, &fc->flags);
419 DMEMIT("%u ", drop_writes + error_writes + (fc->corrupt_bio_byte > 0) * 5);
422 DMEMIT("drop_writes ");
423 else if (error_writes)
424 DMEMIT("error_writes ");
426 if (fc->corrupt_bio_byte)
427 DMEMIT("corrupt_bio_byte %u %c %u %u ",
428 fc->corrupt_bio_byte,
429 (fc->corrupt_bio_rw == WRITE) ? 'w' : 'r',
430 fc->corrupt_bio_value, fc->corrupt_bio_flags);
436 static int flakey_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
438 struct flakey_c *fc = ti->private;
440 *bdev = fc->dev->bdev;
443 * Only pass ioctls through if the device sizes match exactly.
446 ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT)
451 #ifdef CONFIG_BLK_DEV_ZONED
452 static int flakey_report_zones(struct dm_target *ti, sector_t sector,
453 struct blk_zone *zones, unsigned int *nr_zones,
456 struct flakey_c *fc = ti->private;
459 /* Do report and remap it */
460 ret = blkdev_report_zones(fc->dev->bdev, flakey_map_sector(ti, sector),
461 zones, nr_zones, gfp_mask);
466 dm_remap_zone_report(ti, fc->start, zones, nr_zones);
471 static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
473 struct flakey_c *fc = ti->private;
475 return fn(ti, fc->dev, fc->start, ti->len, data);
478 static struct target_type flakey_target = {
480 .version = {1, 5, 0},
481 #ifdef CONFIG_BLK_DEV_ZONED
482 .features = DM_TARGET_ZONED_HM,
483 .report_zones = flakey_report_zones,
485 .module = THIS_MODULE,
489 .end_io = flakey_end_io,
490 .status = flakey_status,
491 .prepare_ioctl = flakey_prepare_ioctl,
492 .iterate_devices = flakey_iterate_devices,
495 static int __init dm_flakey_init(void)
497 int r = dm_register_target(&flakey_target);
500 DMERR("register failed %d", r);
505 static void __exit dm_flakey_exit(void)
507 dm_unregister_target(&flakey_target);
511 module_init(dm_flakey_init);
512 module_exit(dm_flakey_exit);
514 MODULE_DESCRIPTION(DM_NAME " flakey target");
515 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
516 MODULE_LICENSE("GPL");