| /* |
| * Copyright (C) 2003 Sistina Software (UK) Limited. |
| * Copyright (C) 2004, 2010-2011 Red Hat, Inc. All rights reserved. |
| * |
| * This file is released under the GPL. |
| */ |
| |
| #include <linux/device-mapper.h> |
| |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/blkdev.h> |
| #include <linux/bio.h> |
| #include <linux/slab.h> |
| |
| #define DM_MSG_PREFIX "flakey" |
| |
| #define all_corrupt_bio_flags_match(bio, fc) \ |
| (((bio)->bi_opf & (fc)->corrupt_bio_flags) == (fc)->corrupt_bio_flags) |
| |
| /* |
| * Flakey: Used for testing only, simulates intermittent, |
| * catastrophic device failure. |
| */ |
| struct flakey_c { |
| struct dm_dev *dev; |
| unsigned long start_time; |
| sector_t start; |
| unsigned up_interval; |
| unsigned down_interval; |
| unsigned long flags; |
| unsigned corrupt_bio_byte; |
| unsigned corrupt_bio_rw; |
| unsigned corrupt_bio_value; |
| unsigned corrupt_bio_flags; |
| }; |
| |
| enum feature_flag_bits { |
| DROP_WRITES, |
| ERROR_WRITES |
| }; |
| |
| struct per_bio_data { |
| bool bio_submitted; |
| }; |
| |
| static int parse_features(struct dm_arg_set *as, struct flakey_c *fc, |
| struct dm_target *ti) |
| { |
| int r; |
| unsigned argc; |
| const char *arg_name; |
| |
| static const struct dm_arg _args[] = { |
| {0, 6, "Invalid number of feature args"}, |
| {1, UINT_MAX, "Invalid corrupt bio byte"}, |
| {0, 255, "Invalid corrupt value to write into bio byte (0-255)"}, |
| {0, UINT_MAX, "Invalid corrupt bio flags mask"}, |
| }; |
| |
| /* No feature arguments supplied. */ |
| if (!as->argc) |
| return 0; |
| |
| r = dm_read_arg_group(_args, as, &argc, &ti->error); |
| if (r) |
| return r; |
| |
| while (argc) { |
| arg_name = dm_shift_arg(as); |
| argc--; |
| |
| if (!arg_name) { |
| ti->error = "Insufficient feature arguments"; |
| return -EINVAL; |
| } |
| |
| /* |
| * drop_writes |
| */ |
| if (!strcasecmp(arg_name, "drop_writes")) { |
| if (test_and_set_bit(DROP_WRITES, &fc->flags)) { |
| ti->error = "Feature drop_writes duplicated"; |
| return -EINVAL; |
| } else if (test_bit(ERROR_WRITES, &fc->flags)) { |
| ti->error = "Feature drop_writes conflicts with feature error_writes"; |
| return -EINVAL; |
| } |
| |
| continue; |
| } |
| |
| /* |
| * error_writes |
| */ |
| if (!strcasecmp(arg_name, "error_writes")) { |
| if (test_and_set_bit(ERROR_WRITES, &fc->flags)) { |
| ti->error = "Feature error_writes duplicated"; |
| return -EINVAL; |
| |
| } else if (test_bit(DROP_WRITES, &fc->flags)) { |
| ti->error = "Feature error_writes conflicts with feature drop_writes"; |
| return -EINVAL; |
| } |
| |
| continue; |
| } |
| |
| /* |
| * corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags> |
| */ |
| if (!strcasecmp(arg_name, "corrupt_bio_byte")) { |
| if (!argc) { |
| ti->error = "Feature corrupt_bio_byte requires parameters"; |
| return -EINVAL; |
| } |
| |
| r = dm_read_arg(_args + 1, as, &fc->corrupt_bio_byte, &ti->error); |
| if (r) |
| return r; |
| argc--; |
| |
| /* |
| * Direction r or w? |
| */ |
| arg_name = dm_shift_arg(as); |
| if (!strcasecmp(arg_name, "w")) |
| fc->corrupt_bio_rw = WRITE; |
| else if (!strcasecmp(arg_name, "r")) |
| fc->corrupt_bio_rw = READ; |
| else { |
| ti->error = "Invalid corrupt bio direction (r or w)"; |
| return -EINVAL; |
| } |
| argc--; |
| |
| /* |
| * Value of byte (0-255) to write in place of correct one. |
| */ |
| r = dm_read_arg(_args + 2, as, &fc->corrupt_bio_value, &ti->error); |
| if (r) |
| return r; |
| argc--; |
| |
| /* |
| * Only corrupt bios with these flags set. |
| */ |
| r = dm_read_arg(_args + 3, as, &fc->corrupt_bio_flags, &ti->error); |
| if (r) |
| return r; |
| argc--; |
| |
| continue; |
| } |
| |
| ti->error = "Unrecognised flakey feature requested"; |
| return -EINVAL; |
| } |
| |
| if (test_bit(DROP_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) { |
| ti->error = "drop_writes is incompatible with corrupt_bio_byte with the WRITE flag set"; |
| return -EINVAL; |
| |
| } else if (test_bit(ERROR_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) { |
| ti->error = "error_writes is incompatible with corrupt_bio_byte with the WRITE flag set"; |
| return -EINVAL; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Construct a flakey mapping: |
| * <dev_path> <offset> <up interval> <down interval> [<#feature args> [<arg>]*] |
| * |
| * Feature args: |
| * [drop_writes] |
| * [corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>] |
| * |
| * Nth_byte starts from 1 for the first byte. |
| * Direction is r for READ or w for WRITE. |
| * bio_flags is ignored if 0. |
| */ |
| static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv) |
| { |
| static const struct dm_arg _args[] = { |
| {0, UINT_MAX, "Invalid up interval"}, |
| {0, UINT_MAX, "Invalid down interval"}, |
| }; |
| |
| int r; |
| struct flakey_c *fc; |
| unsigned long long tmpll; |
| struct dm_arg_set as; |
| const char *devname; |
| char dummy; |
| |
| as.argc = argc; |
| as.argv = argv; |
| |
| if (argc < 4) { |
| ti->error = "Invalid argument count"; |
| return -EINVAL; |
| } |
| |
| fc = kzalloc(sizeof(*fc), GFP_KERNEL); |
| if (!fc) { |
| ti->error = "Cannot allocate context"; |
| return -ENOMEM; |
| } |
| fc->start_time = jiffies; |
| |
| devname = dm_shift_arg(&as); |
| |
| r = -EINVAL; |
| if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1) { |
| ti->error = "Invalid device sector"; |
| goto bad; |
| } |
| fc->start = tmpll; |
| |
| r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error); |
| if (r) |
| goto bad; |
| |
| r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error); |
| if (r) |
| goto bad; |
| |
| if (!(fc->up_interval + fc->down_interval)) { |
| ti->error = "Total (up + down) interval is zero"; |
| r = -EINVAL; |
| goto bad; |
| } |
| |
| if (fc->up_interval + fc->down_interval < fc->up_interval) { |
| ti->error = "Interval overflow"; |
| r = -EINVAL; |
| goto bad; |
| } |
| |
| r = parse_features(&as, fc, ti); |
| if (r) |
| goto bad; |
| |
| r = dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev); |
| if (r) { |
| ti->error = "Device lookup failed"; |
| goto bad; |
| } |
| |
| ti->num_flush_bios = 1; |
| ti->num_discard_bios = 1; |
| ti->per_io_data_size = sizeof(struct per_bio_data); |
| ti->private = fc; |
| return 0; |
| |
| bad: |
| kfree(fc); |
| return r; |
| } |
| |
| static void flakey_dtr(struct dm_target *ti) |
| { |
| struct flakey_c *fc = ti->private; |
| |
| dm_put_device(ti, fc->dev); |
| kfree(fc); |
| } |
| |
| static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector) |
| { |
| struct flakey_c *fc = ti->private; |
| |
| return fc->start + dm_target_offset(ti, bi_sector); |
| } |
| |
| static void flakey_map_bio(struct dm_target *ti, struct bio *bio) |
| { |
| struct flakey_c *fc = ti->private; |
| |
| bio_set_dev(bio, fc->dev->bdev); |
| if (bio_sectors(bio) || bio_op(bio) == REQ_OP_ZONE_RESET) |
| bio->bi_iter.bi_sector = |
| flakey_map_sector(ti, bio->bi_iter.bi_sector); |
| } |
| |
| static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc) |
| { |
| unsigned bio_bytes = bio_cur_bytes(bio); |
| char *data = bio_data(bio); |
| |
| /* |
| * Overwrite the Nth byte of the data returned. |
| */ |
| if (data && bio_bytes >= fc->corrupt_bio_byte) { |
| data[fc->corrupt_bio_byte - 1] = fc->corrupt_bio_value; |
| |
| DMDEBUG("Corrupting data bio=%p by writing %u to byte %u " |
| "(rw=%c bi_opf=%u bi_sector=%llu cur_bytes=%u)\n", |
| bio, fc->corrupt_bio_value, fc->corrupt_bio_byte, |
| (bio_data_dir(bio) == WRITE) ? 'w' : 'r', bio->bi_opf, |
| (unsigned long long)bio->bi_iter.bi_sector, bio_bytes); |
| } |
| } |
| |
| static int flakey_map(struct dm_target *ti, struct bio *bio) |
| { |
| struct flakey_c *fc = ti->private; |
| unsigned elapsed; |
| struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data)); |
| pb->bio_submitted = false; |
| |
| /* Do not fail reset zone */ |
| if (bio_op(bio) == REQ_OP_ZONE_RESET) |
| goto map_bio; |
| |
| /* Are we alive ? */ |
| elapsed = (jiffies - fc->start_time) / HZ; |
| if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) { |
| /* |
| * Flag this bio as submitted while down. |
| */ |
| pb->bio_submitted = true; |
| |
| /* |
| * Error reads if neither corrupt_bio_byte or drop_writes or error_writes are set. |
| * Otherwise, flakey_end_io() will decide if the reads should be modified. |
| */ |
| if (bio_data_dir(bio) == READ) { |
| if (!fc->corrupt_bio_byte && !test_bit(DROP_WRITES, &fc->flags) && |
| !test_bit(ERROR_WRITES, &fc->flags)) |
| return DM_MAPIO_KILL; |
| goto map_bio; |
| } |
| |
| /* |
| * Drop or error writes? |
| */ |
| if (test_bit(DROP_WRITES, &fc->flags)) { |
| bio_endio(bio); |
| return DM_MAPIO_SUBMITTED; |
| } |
| else if (test_bit(ERROR_WRITES, &fc->flags)) { |
| bio_io_error(bio); |
| return DM_MAPIO_SUBMITTED; |
| } |
| |
| /* |
| * Corrupt matching writes. |
| */ |
| if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == WRITE)) { |
| if (all_corrupt_bio_flags_match(bio, fc)) |
| corrupt_bio_data(bio, fc); |
| goto map_bio; |
| } |
| |
| /* |
| * By default, error all I/O. |
| */ |
| return DM_MAPIO_KILL; |
| } |
| |
| map_bio: |
| flakey_map_bio(ti, bio); |
| |
| return DM_MAPIO_REMAPPED; |
| } |
| |
| static int flakey_end_io(struct dm_target *ti, struct bio *bio, |
| blk_status_t *error) |
| { |
| struct flakey_c *fc = ti->private; |
| struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data)); |
| |
| if (bio_op(bio) == REQ_OP_ZONE_RESET) |
| return DM_ENDIO_DONE; |
| |
| if (!*error && pb->bio_submitted && (bio_data_dir(bio) == READ)) { |
| if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == READ) && |
| all_corrupt_bio_flags_match(bio, fc)) { |
| /* |
| * Corrupt successful matching READs while in down state. |
| */ |
| corrupt_bio_data(bio, fc); |
| |
| } else if (!test_bit(DROP_WRITES, &fc->flags) && |
| !test_bit(ERROR_WRITES, &fc->flags)) { |
| /* |
| * Error read during the down_interval if drop_writes |
| * and error_writes were not configured. |
| */ |
| *error = BLK_STS_IOERR; |
| } |
| } |
| |
| return DM_ENDIO_DONE; |
| } |
| |
| static void flakey_status(struct dm_target *ti, status_type_t type, |
| unsigned status_flags, char *result, unsigned maxlen) |
| { |
| unsigned sz = 0; |
| struct flakey_c *fc = ti->private; |
| unsigned drop_writes, error_writes; |
| |
| switch (type) { |
| case STATUSTYPE_INFO: |
| result[0] = '\0'; |
| break; |
| |
| case STATUSTYPE_TABLE: |
| DMEMIT("%s %llu %u %u ", fc->dev->name, |
| (unsigned long long)fc->start, fc->up_interval, |
| fc->down_interval); |
| |
| drop_writes = test_bit(DROP_WRITES, &fc->flags); |
| error_writes = test_bit(ERROR_WRITES, &fc->flags); |
| DMEMIT("%u ", drop_writes + error_writes + (fc->corrupt_bio_byte > 0) * 5); |
| |
| if (drop_writes) |
| DMEMIT("drop_writes "); |
| else if (error_writes) |
| DMEMIT("error_writes "); |
| |
| if (fc->corrupt_bio_byte) |
| DMEMIT("corrupt_bio_byte %u %c %u %u ", |
| fc->corrupt_bio_byte, |
| (fc->corrupt_bio_rw == WRITE) ? 'w' : 'r', |
| fc->corrupt_bio_value, fc->corrupt_bio_flags); |
| |
| break; |
| } |
| } |
| |
| static int flakey_prepare_ioctl(struct dm_target *ti, struct block_device **bdev) |
| { |
| struct flakey_c *fc = ti->private; |
| |
| *bdev = fc->dev->bdev; |
| |
| /* |
| * Only pass ioctls through if the device sizes match exactly. |
| */ |
| if (fc->start || |
| ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT) |
| return 1; |
| return 0; |
| } |
| |
| #ifdef CONFIG_BLK_DEV_ZONED |
| static int flakey_report_zones(struct dm_target *ti, sector_t sector, |
| struct blk_zone *zones, unsigned int *nr_zones, |
| gfp_t gfp_mask) |
| { |
| struct flakey_c *fc = ti->private; |
| int ret; |
| |
| /* Do report and remap it */ |
| ret = blkdev_report_zones(fc->dev->bdev, flakey_map_sector(ti, sector), |
| zones, nr_zones, gfp_mask); |
| if (ret != 0) |
| return ret; |
| |
| if (*nr_zones) |
| dm_remap_zone_report(ti, fc->start, zones, nr_zones); |
| return 0; |
| } |
| #endif |
| |
| static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data) |
| { |
| struct flakey_c *fc = ti->private; |
| |
| return fn(ti, fc->dev, fc->start, ti->len, data); |
| } |
| |
| static struct target_type flakey_target = { |
| .name = "flakey", |
| .version = {1, 5, 0}, |
| #ifdef CONFIG_BLK_DEV_ZONED |
| .features = DM_TARGET_ZONED_HM, |
| .report_zones = flakey_report_zones, |
| #endif |
| .module = THIS_MODULE, |
| .ctr = flakey_ctr, |
| .dtr = flakey_dtr, |
| .map = flakey_map, |
| .end_io = flakey_end_io, |
| .status = flakey_status, |
| .prepare_ioctl = flakey_prepare_ioctl, |
| .iterate_devices = flakey_iterate_devices, |
| }; |
| |
| static int __init dm_flakey_init(void) |
| { |
| int r = dm_register_target(&flakey_target); |
| |
| if (r < 0) |
| DMERR("register failed %d", r); |
| |
| return r; |
| } |
| |
| static void __exit dm_flakey_exit(void) |
| { |
| dm_unregister_target(&flakey_target); |
| } |
| |
| /* Module hooks */ |
| module_init(dm_flakey_init); |
| module_exit(dm_flakey_exit); |
| |
| MODULE_DESCRIPTION(DM_NAME " flakey target"); |
| MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); |
| MODULE_LICENSE("GPL"); |