[linux-2.6-block.git] / drivers / md / dm-flakey.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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 int up_interval;
	unsigned int down_interval;
	unsigned long flags;
	unsigned int corrupt_bio_byte;
	unsigned int corrupt_bio_rw;
	unsigned int corrupt_bio_value;
	blk_opf_t corrupt_bio_flags;
};

enum feature_flag_bits {
	ERROR_READS,
	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 int argc;
	const char *arg_name;

	static const struct dm_arg _args[] = {
		{0, 7, "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;
		}

		/*
		 * error_reads
		 */
		if (!strcasecmp(arg_name, "error_reads")) {
			if (test_and_set_bit(ERROR_READS, &fc->flags)) {
				ti->error = "Feature error_reads duplicated";
				return -EINVAL;
			}
			continue;
		}

		/*
		 * 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 (arg_name && !strcasecmp(arg_name, "w"))
				fc->corrupt_bio_rw = WRITE;
			else if (arg_name && !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.
			 */
			BUILD_BUG_ON(sizeof(fc->corrupt_bio_flags) !=
				     sizeof(unsigned int));
			r = dm_read_arg(_args + 3, as,
				(__force unsigned int *)&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;
	}

	if (!fc->corrupt_bio_byte && !test_bit(ERROR_READS, &fc->flags) &&
	    !test_bit(DROP_WRITES, &fc->flags) && !test_bit(ERROR_WRITES, &fc->flags)) {
		set_bit(ERROR_WRITES, &fc->flags);
		set_bit(ERROR_READS, &fc->flags);
	}

	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 || tmpll != (sector_t)tmpll) {
		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);
	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 int corrupt_bio_byte = fc->corrupt_bio_byte - 1;

	struct bvec_iter iter;
	struct bio_vec bvec;

	if (!bio_has_data(bio))
		return;

	/*
	 * Overwrite the Nth byte of the bio's data, on whichever page
	 * it falls.
	 */
	bio_for_each_segment(bvec, bio, iter) {
		if (bio_iter_len(bio, iter) > corrupt_bio_byte) {
			char *segment;
			struct page *page = bio_iter_page(bio, iter);
			if (unlikely(page == ZERO_PAGE(0)))
				break;
			segment = bvec_kmap_local(&bvec);
			segment[corrupt_bio_byte] = fc->corrupt_bio_value;
			kunmap_local(segment);
			DMDEBUG("Corrupting data bio=%p by writing %u to byte %u "
				"(rw=%c bi_opf=%u bi_sector=%llu size=%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->bi_iter.bi_size);
			break;
		}
		corrupt_bio_byte -= bio_iter_len(bio, iter);
	}
}

static int flakey_map(struct dm_target *ti, struct bio *bio)
{
	struct flakey_c *fc = ti->private;
	unsigned int elapsed;
	struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));

	pb->bio_submitted = false;

	if (op_is_zone_mgmt(bio_op(bio)))
		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 (test_bit(ERROR_READS, &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) {
			if (fc->corrupt_bio_rw == WRITE) {
				if (all_corrupt_bio_flags_match(bio, fc))
					corrupt_bio_data(bio, fc);
			}
			goto map_bio;
		}
	}

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 (op_is_zone_mgmt(bio_op(bio)))
		return DM_ENDIO_DONE;

	if (!*error && pb->bio_submitted && (bio_data_dir(bio) == READ)) {
		if (fc->corrupt_bio_byte) {
			if ((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);
			}
		}
		if (test_bit(ERROR_READS, &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 int status_flags, char *result, unsigned int maxlen)
{
	unsigned int sz = 0;
	struct flakey_c *fc = ti->private;
	unsigned int error_reads, 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);

		error_reads = test_bit(ERROR_READS, &fc->flags);
		drop_writes = test_bit(DROP_WRITES, &fc->flags);
		error_writes = test_bit(ERROR_WRITES, &fc->flags);
		DMEMIT(" %u", error_reads + drop_writes + error_writes + (fc->corrupt_bio_byte > 0) * 5);

		if (error_reads)
			DMEMIT(" error_reads");
		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;

	case STATUSTYPE_IMA:
		result[0] = '\0';
		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 != bdev_nr_sectors((*bdev)))
		return 1;
	return 0;
}

#ifdef CONFIG_BLK_DEV_ZONED
static int flakey_report_zones(struct dm_target *ti,
		struct dm_report_zones_args *args, unsigned int nr_zones)
{
	struct flakey_c *fc = ti->private;

	return dm_report_zones(fc->dev->bdev, fc->start,
			       flakey_map_sector(ti, args->next_sector),
			       args, nr_zones);
}
#else
#define flakey_report_zones NULL
#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},
	.features = DM_TARGET_ZONED_HM | DM_TARGET_PASSES_CRYPTO,
	.report_zones = flakey_report_zones,
	.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,
};
module_dm(flakey);

MODULE_DESCRIPTION(DM_NAME " flakey target");
MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
MODULE_LICENSE("GPL");
Commit	Line	Data
3bd94003	1	// SPDX-License-Identifier: GPL-2.0-only
3407ef52 JB	2	/*
3407ef52 JB	3	* Copyright (C) 2003 Sistina Software (UK) Limited.
a3998799	4	* Copyright (C) 2004, 2010-2011 Red Hat, Inc. All rights reserved.
3407ef52 JB	5	*
	6	* This file is released under the GPL.
	7	*/
	8
	9	#include <linux/device-mapper.h>
	10
	11	#include <linux/module.h>
	12	#include <linux/init.h>
	13	#include <linux/blkdev.h>
	14	#include <linux/bio.h>
	15	#include <linux/slab.h>
	16
	17	#define DM_MSG_PREFIX "flakey"
	18
a3998799	19	#define all_corrupt_bio_flags_match(bio, fc) \
1eff9d32	20	(((bio)->bi_opf & (fc)->corrupt_bio_flags) == (fc)->corrupt_bio_flags)
a3998799	21
3407ef52 JB	22	/*
	23	* Flakey: Used for testing only, simulates intermittent,
	24	* catastrophic device failure.
	25	*/
	26	struct flakey_c {
	27	struct dm_dev *dev;
	28	unsigned long start_time;
	29	sector_t start;
86a3238c HM	30	unsigned int up_interval;
86a3238c HM	31	unsigned int down_interval;
b26f5e3d	32	unsigned long flags;
86a3238c HM	33	unsigned int corrupt_bio_byte;
	34	unsigned int corrupt_bio_rw;
	35	unsigned int corrupt_bio_value;
eff17e51	36	blk_opf_t corrupt_bio_flags;
3407ef52 JB	37	};
3407ef52 JB	38
b26f5e3d	39	enum feature_flag_bits {
aa7d7bc9	40	ERROR_READS,
ef548c55 MS	41	DROP_WRITES,
ef548c55 MS	42	ERROR_WRITES
b26f5e3d MS	43	};
b26f5e3d MS	44
c7cfdf59 MP	45	struct per_bio_data {
	46	bool bio_submitted;
	47	};
	48
b26f5e3d MS	49	static int parse_features(struct dm_arg_set as, struct flakey_c fc,
b26f5e3d MS	50	struct dm_target *ti)
dfd068b0 MS	51	{
dfd068b0 MS	52	int r;
86a3238c	53	unsigned int argc;
dfd068b0 MS	54	const char *arg_name;
dfd068b0 MS	55
5916a22b	56	static const struct dm_arg _args[] = {
aa7d7bc9	57	{0, 7, "Invalid number of feature args"},
a3998799 MS	58	{1, UINT_MAX, "Invalid corrupt bio byte"},
	59	{0, 255, "Invalid corrupt value to write into bio byte (0-255)"},
	60	{0, UINT_MAX, "Invalid corrupt bio flags mask"},
dfd068b0 MS	61	};
	62
	63	/* No feature arguments supplied. */
	64	if (!as->argc)
	65	return 0;
	66
	67	r = dm_read_arg_group(_args, as, &argc, &ti->error);
	68	if (r)
a3998799	69	return r;
dfd068b0	70
a3998799	71	while (argc) {
dfd068b0 MS	72	arg_name = dm_shift_arg(as);
	73	argc--;
	74
7690e253 GR	75	if (!arg_name) {
	76	ti->error = "Insufficient feature arguments";
	77	return -EINVAL;
	78	}
	79
aa7d7bc9 MP	80	/*
	81	* error_reads
	82	*/
	83	if (!strcasecmp(arg_name, "error_reads")) {
	84	if (test_and_set_bit(ERROR_READS, &fc->flags)) {
	85	ti->error = "Feature error_reads duplicated";
	86	return -EINVAL;
	87	}
	88	continue;
	89	}
	90
b26f5e3d MS	91	/*
	92	* drop_writes
	93	*/
	94	if (!strcasecmp(arg_name, "drop_writes")) {
	95	if (test_and_set_bit(DROP_WRITES, &fc->flags)) {
	96	ti->error = "Feature drop_writes duplicated";
	97	return -EINVAL;
ef548c55 MS	98	} else if (test_bit(ERROR_WRITES, &fc->flags)) {
	99	ti->error = "Feature drop_writes conflicts with feature error_writes";
	100	return -EINVAL;
	101	}
	102
	103	continue;
	104	}
	105
	106	/*
	107	* error_writes
	108	*/
	109	if (!strcasecmp(arg_name, "error_writes")) {
	110	if (test_and_set_bit(ERROR_WRITES, &fc->flags)) {
	111	ti->error = "Feature error_writes duplicated";
	112	return -EINVAL;
	113
	114	} else if (test_bit(DROP_WRITES, &fc->flags)) {
	115	ti->error = "Feature error_writes conflicts with feature drop_writes";
	116	return -EINVAL;
b26f5e3d MS	117	}
	118
	119	continue;
	120	}
	121
a3998799 MS	122	/*
	123	* corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>
	124	*/
	125	if (!strcasecmp(arg_name, "corrupt_bio_byte")) {
68e58a29	126	if (!argc) {
a3998799	127	ti->error = "Feature corrupt_bio_byte requires parameters";
68e58a29 MS	128	return -EINVAL;
68e58a29 MS	129	}
a3998799 MS	130
	131	r = dm_read_arg(_args + 1, as, &fc->corrupt_bio_byte, &ti->error);
	132	if (r)
	133	return r;
	134	argc--;
	135
	136	/*
	137	* Direction r or w?
	138	*/
	139	arg_name = dm_shift_arg(as);
98dba02d	140	if (arg_name && !strcasecmp(arg_name, "w"))
a3998799	141	fc->corrupt_bio_rw = WRITE;
98dba02d	142	else if (arg_name && !strcasecmp(arg_name, "r"))
a3998799 MS	143	fc->corrupt_bio_rw = READ;
	144	else {
	145	ti->error = "Invalid corrupt bio direction (r or w)";
	146	return -EINVAL;
	147	}
	148	argc--;
	149
	150	/*
	151	* Value of byte (0-255) to write in place of correct one.
	152	*/
	153	r = dm_read_arg(_args + 2, as, &fc->corrupt_bio_value, &ti->error);
	154	if (r)
	155	return r;
	156	argc--;
	157
	158	/*
	159	* Only corrupt bios with these flags set.
	160	*/
eff17e51 BVA	161	BUILD_BUG_ON(sizeof(fc->corrupt_bio_flags) !=
	162	sizeof(unsigned int));
	163	r = dm_read_arg(_args + 3, as,
86a3238c	164	(__force unsigned int *)&fc->corrupt_bio_flags,
eff17e51	165	&ti->error);
a3998799 MS	166	if (r)
	167	return r;
	168	argc--;
	169
	170	continue;
	171	}
	172
dfd068b0	173	ti->error = "Unrecognised flakey feature requested";
a3998799	174	return -EINVAL;
dfd068b0 MS	175	}
dfd068b0 MS	176
a3998799 MS	177	if (test_bit(DROP_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) {
	178	ti->error = "drop_writes is incompatible with corrupt_bio_byte with the WRITE flag set";
	179	return -EINVAL;
ef548c55 MS	180
	181	} else if (test_bit(ERROR_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) {
	182	ti->error = "error_writes is incompatible with corrupt_bio_byte with the WRITE flag set";
	183	return -EINVAL;
a3998799 MS	184	}
a3998799 MS	185
aa7d7bc9 MP	186	if (!fc->corrupt_bio_byte && !test_bit(ERROR_READS, &fc->flags) &&
	187	!test_bit(DROP_WRITES, &fc->flags) && !test_bit(ERROR_WRITES, &fc->flags)) {
	188	set_bit(ERROR_WRITES, &fc->flags);
	189	set_bit(ERROR_READS, &fc->flags);
	190	}
	191
a3998799	192	return 0;
dfd068b0 MS	193	}
dfd068b0 MS	194
3407ef52	195	/*
dfd068b0 MS	196	* Construct a flakey mapping:
dfd068b0 MS	197	* <dev_path> <offset> <up interval> <down interval> [<#feature args> [<arg>]*]
b26f5e3d MS	198	*
	199	* Feature args:
	200	* [drop_writes]
a3998799 MS	201	* [corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>]
	202	*
	203	* Nth_byte starts from 1 for the first byte.
	204	* Direction is r for READ or w for WRITE.
	205	* bio_flags is ignored if 0.
3407ef52 JB	206	*/
	207	static int flakey_ctr(struct dm_target ti, unsigned int argc, char *argv)
	208	{
5916a22b	209	static const struct dm_arg _args[] = {
dfd068b0 MS	210	{0, UINT_MAX, "Invalid up interval"},
	211	{0, UINT_MAX, "Invalid down interval"},
	212	};
	213
	214	int r;
3407ef52	215	struct flakey_c *fc;
dfd068b0 MS	216	unsigned long long tmpll;
	217	struct dm_arg_set as;
	218	const char *devname;
31998ef1	219	char dummy;
3407ef52	220
dfd068b0 MS	221	as.argc = argc;
	222	as.argv = argv;
	223
	224	if (argc < 4) {
	225	ti->error = "Invalid argument count";
3407ef52 JB	226	return -EINVAL;
	227	}
	228
b26f5e3d	229	fc = kzalloc(sizeof(*fc), GFP_KERNEL);
3407ef52	230	if (!fc) {
75e3a0f5	231	ti->error = "Cannot allocate context";
3407ef52 JB	232	return -ENOMEM;
	233	}
	234	fc->start_time = jiffies;
	235
dfd068b0 MS	236	devname = dm_shift_arg(&as);
dfd068b0 MS	237
e80d1c80	238	r = -EINVAL;
ef87bfc2	239	if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1 \|\| tmpll != (sector_t)tmpll) {
dfd068b0	240	ti->error = "Invalid device sector";
3407ef52 JB	241	goto bad;
3407ef52 JB	242	}
dfd068b0	243	fc->start = tmpll;
3407ef52	244
dfd068b0 MS	245	r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
dfd068b0 MS	246	if (r)
3407ef52	247	goto bad;
3407ef52	248
dfd068b0 MS	249	r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
dfd068b0 MS	250	if (r)
3407ef52	251	goto bad;
3407ef52 JB	252
3407ef52 JB	253	if (!(fc->up_interval + fc->down_interval)) {
dfd068b0	254	ti->error = "Total (up + down) interval is zero";
bff7e067	255	r = -EINVAL;
3407ef52 JB	256	goto bad;
	257	}
	258
	259	if (fc->up_interval + fc->down_interval < fc->up_interval) {
dfd068b0	260	ti->error = "Interval overflow";
bff7e067	261	r = -EINVAL;
3407ef52 JB	262	goto bad;
	263	}
	264
b26f5e3d	265	r = parse_features(&as, fc, ti);
dfd068b0 MS	266	if (r)
	267	goto bad;
	268
e80d1c80 VG	269	r = dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev);
e80d1c80 VG	270	if (r) {
dfd068b0	271	ti->error = "Device lookup failed";
3407ef52 JB	272	goto bad;
	273	}
	274
55a62eef AK	275	ti->num_flush_bios = 1;
55a62eef AK	276	ti->num_discard_bios = 1;
30187e1d	277	ti->per_io_data_size = sizeof(struct per_bio_data);
3407ef52 JB	278	ti->private = fc;
	279	return 0;
	280
	281	bad:
	282	kfree(fc);
e80d1c80	283	return r;
3407ef52 JB	284	}
	285
	286	static void flakey_dtr(struct dm_target *ti)
	287	{
	288	struct flakey_c *fc = ti->private;
	289
	290	dm_put_device(ti, fc->dev);
	291	kfree(fc);
	292	}
	293
	294	static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector)
	295	{
	296	struct flakey_c *fc = ti->private;
	297
30e4171b	298	return fc->start + dm_target_offset(ti, bi_sector);
3407ef52 JB	299	}
	300
	301	static void flakey_map_bio(struct dm_target ti, struct bio bio)
	302	{
	303	struct flakey_c *fc = ti->private;
	304
74d46992	305	bio_set_dev(bio, fc->dev->bdev);
e86f2b00	306	bio->bi_iter.bi_sector = flakey_map_sector(ti, bio->bi_iter.bi_sector);
3407ef52 JB	307	}
3407ef52 JB	308
a3998799 MS	309	static void corrupt_bio_data(struct bio bio, struct flakey_c fc)
a3998799 MS	310	{
a00f5276 ST	311	unsigned int corrupt_bio_byte = fc->corrupt_bio_byte - 1;
	312
	313	struct bvec_iter iter;
	314	struct bio_vec bvec;
	315
	316	if (!bio_has_data(bio))
	317	return;
a3998799 MS	318
a3998799 MS	319	/*
a00f5276 ST	320	* Overwrite the Nth byte of the bio's data, on whichever page
a00f5276 ST	321	* it falls.
a3998799	322	*/
a00f5276 ST	323	bio_for_each_segment(bvec, bio, iter) {
a00f5276 ST	324	if (bio_iter_len(bio, iter) > corrupt_bio_byte) {
f50714b5 MP	325	char *segment;
	326	struct page *page = bio_iter_page(bio, iter);
	327	if (unlikely(page == ZERO_PAGE(0)))
	328	break;
8eb29c4f	329	segment = bvec_kmap_local(&bvec);
a00f5276	330	segment[corrupt_bio_byte] = fc->corrupt_bio_value;
8eb29c4f	331	kunmap_local(segment);
a00f5276 ST	332	DMDEBUG("Corrupting data bio=%p by writing %u to byte %u "
	333	"(rw=%c bi_opf=%u bi_sector=%llu size=%u)\n",
	334	bio, fc->corrupt_bio_value, fc->corrupt_bio_byte,
	335	(bio_data_dir(bio) == WRITE) ? 'w' : 'r', bio->bi_opf,
	336	(unsigned long long)bio->bi_iter.bi_sector, bio->bi_iter.bi_size);
	337	break;
	338	}
	339	corrupt_bio_byte -= bio_iter_len(bio, iter);
a3998799 MS	340	}
	341	}
	342
7de3ee57	343	static int flakey_map(struct dm_target ti, struct bio bio)
3407ef52 JB	344	{
3407ef52 JB	345	struct flakey_c *fc = ti->private;
86a3238c	346	unsigned int elapsed;
c7cfdf59	347	struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
0ef0b471	348
c7cfdf59	349	pb->bio_submitted = false;
3407ef52	350
2e2d6f7e	351	if (op_is_zone_mgmt(bio_op(bio)))
124c4454 DLM	352	goto map_bio;
124c4454 DLM	353
3407ef52 JB	354	/* Are we alive ? */
3407ef52 JB	355	elapsed = (jiffies - fc->start_time) / HZ;
b26f5e3d	356	if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
a3998799 MS	357	/*
	358	* Flag this bio as submitted while down.
	359	*/
c7cfdf59	360	pb->bio_submitted = true;
a3998799 MS	361
a3998799 MS	362	/*
ef548c55	363	* Error reads if neither corrupt_bio_byte or drop_writes or error_writes are set.
299f6230	364	* Otherwise, flakey_end_io() will decide if the reads should be modified.
a3998799	365	*/
99f3c90d	366	if (bio_data_dir(bio) == READ) {
aa7d7bc9	367	if (test_bit(ERROR_READS, &fc->flags))
846785e6	368	return DM_MAPIO_KILL;
299f6230	369	goto map_bio;
99f3c90d	370	}
b26f5e3d MS	371
b26f5e3d MS	372	/*
ef548c55	373	* Drop or error writes?
b26f5e3d MS	374	*/
b26f5e3d MS	375	if (test_bit(DROP_WRITES, &fc->flags)) {
4246a0b6	376	bio_endio(bio);
a3998799	377	return DM_MAPIO_SUBMITTED;
03b18887	378	} else if (test_bit(ERROR_WRITES, &fc->flags)) {
ef548c55 MS	379	bio_io_error(bio);
	380	return DM_MAPIO_SUBMITTED;
	381	}
a3998799 MS	382
	383	/*
	384	* Corrupt matching writes.
	385	*/
aa56b9b7 MP	386	if (fc->corrupt_bio_byte) {
	387	if (fc->corrupt_bio_rw == WRITE) {
	388	if (all_corrupt_bio_flags_match(bio, fc))
	389	corrupt_bio_data(bio, fc);
	390	}
b26f5e3d MS	391	goto map_bio;
b26f5e3d MS	392	}
b26f5e3d	393	}
3407ef52	394
b26f5e3d	395	map_bio:
3407ef52 JB	396	flakey_map_bio(ti, bio);
	397
	398	return DM_MAPIO_REMAPPED;
	399	}
	400
4e4cbee9	401	static int flakey_end_io(struct dm_target ti, struct bio bio,
124c4454	402	blk_status_t *error)
a3998799 MS	403	{
a3998799 MS	404	struct flakey_c *fc = ti->private;
c7cfdf59	405	struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
a3998799	406
2e2d6f7e	407	if (op_is_zone_mgmt(bio_op(bio)))
124c4454 DLM	408	return DM_ENDIO_DONE;
124c4454 DLM	409
1be56909	410	if (!*error && pb->bio_submitted && (bio_data_dir(bio) == READ)) {
aa56b9b7 MP	411	if (fc->corrupt_bio_byte) {
	412	if ((fc->corrupt_bio_rw == READ) &&
	413	all_corrupt_bio_flags_match(bio, fc)) {
	414	/*
	415	* Corrupt successful matching READs while in down state.
	416	*/
	417	corrupt_bio_data(bio, fc);
	418	}
aa7d7bc9 MP	419	}
aa7d7bc9 MP	420	if (test_bit(ERROR_READS, &fc->flags)) {
299f6230 MS	421	/*
299f6230 MS	422	* Error read during the down_interval if drop_writes
ef548c55	423	* and error_writes were not configured.
299f6230	424	*/
4e4cbee9	425	*error = BLK_STS_IOERR;
299f6230	426	}
99f3c90d	427	}
a3998799	428
1be56909	429	return DM_ENDIO_DONE;
a3998799 MS	430	}
a3998799 MS	431
fd7c092e	432	static void flakey_status(struct dm_target *ti, status_type_t type,
86a3238c	433	unsigned int status_flags, char *result, unsigned int maxlen)
3407ef52	434	{
86a3238c	435	unsigned int sz = 0;
3407ef52	436	struct flakey_c *fc = ti->private;
aa7d7bc9	437	unsigned int error_reads, drop_writes, error_writes;
3407ef52 JB	438
	439	switch (type) {
	440	case STATUSTYPE_INFO:
	441	result[0] = '\0';
	442	break;
	443
	444	case STATUSTYPE_TABLE:
e3675dc1	445	DMEMIT("%s %llu %u %u", fc->dev->name,
b26f5e3d MS	446	(unsigned long long)fc->start, fc->up_interval,
	447	fc->down_interval);
	448
aa7d7bc9	449	error_reads = test_bit(ERROR_READS, &fc->flags);
b26f5e3d	450	drop_writes = test_bit(DROP_WRITES, &fc->flags);
ef548c55	451	error_writes = test_bit(ERROR_WRITES, &fc->flags);
aa7d7bc9	452	DMEMIT(" %u", error_reads + drop_writes + error_writes + (fc->corrupt_bio_byte > 0) * 5);
a3998799	453
aa7d7bc9 MP	454	if (error_reads)
aa7d7bc9 MP	455	DMEMIT(" error_reads");
b26f5e3d	456	if (drop_writes)
e3675dc1	457	DMEMIT(" drop_writes");
ef548c55	458	else if (error_writes)
e3675dc1	459	DMEMIT(" error_writes");
a3998799 MS	460
a3998799 MS	461	if (fc->corrupt_bio_byte)
e3675dc1	462	DMEMIT(" corrupt_bio_byte %u %c %u %u",
a3998799 MS	463	fc->corrupt_bio_byte,
	464	(fc->corrupt_bio_rw == WRITE) ? 'w' : 'r',
	465	fc->corrupt_bio_value, fc->corrupt_bio_flags);
	466
3407ef52	467	break;
8ec45662 TS	468
	469	case STATUSTYPE_IMA:
	470	result[0] = '\0';
	471	break;
3407ef52	472	}
3407ef52 JB	473	}
3407ef52 JB	474
5bd5e8d8	475	static int flakey_prepare_ioctl(struct dm_target ti, struct block_device *bdev)
3407ef52 JB	476	{
3407ef52 JB	477	struct flakey_c *fc = ti->private;
e56f81e0 CH	478
e56f81e0 CH	479	*bdev = fc->dev->bdev;
3407ef52	480
ec8013be PB	481	/*
	482	* Only pass ioctls through if the device sizes match exactly.
	483	*/
6dcbb52c	484	if (fc->start \|\| ti->len != bdev_nr_sectors((*bdev)))
e56f81e0 CH	485	return 1;
e56f81e0 CH	486	return 0;
3407ef52 JB	487	}
3407ef52 JB	488
e76239a3	489	#ifdef CONFIG_BLK_DEV_ZONED
d4100351 CH	490	static int flakey_report_zones(struct dm_target *ti,
d4100351 CH	491	struct dm_report_zones_args *args, unsigned int nr_zones)
e76239a3 CH	492	{
e76239a3 CH	493	struct flakey_c *fc = ti->private;
e76239a3	494
912e8875 DLM	495	return dm_report_zones(fc->dev->bdev, fc->start,
	496	flakey_map_sector(ti, args->next_sector),
	497	args, nr_zones);
e76239a3	498	}
e3290b94 MS	499	#else
e3290b94 MS	500	#define flakey_report_zones NULL
e76239a3 CH	501	#endif
e76239a3 CH	502
3407ef52 JB	503	static int flakey_iterate_devices(struct dm_target ti, iterate_devices_callout_fn fn, void data)
	504	{
	505	struct flakey_c *fc = ti->private;
	506
	507	return fn(ti, fc->dev, fc->start, ti->len, data);
	508	}
	509
	510	static struct target_type flakey_target = {
	511	.name = "flakey",
124c4454	512	.version = {1, 5, 0},
3db564b4	513	.features = DM_TARGET_ZONED_HM \| DM_TARGET_PASSES_CRYPTO,
e76239a3	514	.report_zones = flakey_report_zones,
3407ef52 JB	515	.module = THIS_MODULE,
	516	.ctr = flakey_ctr,
	517	.dtr = flakey_dtr,
	518	.map = flakey_map,
a3998799	519	.end_io = flakey_end_io,
3407ef52	520	.status = flakey_status,
e56f81e0	521	.prepare_ioctl = flakey_prepare_ioctl,
3407ef52 JB	522	.iterate_devices = flakey_iterate_devices,
3407ef52 JB	523	};
3664ff82	524	module_dm(flakey);
3407ef52 JB	525
	526	MODULE_DESCRIPTION(DM_NAME " flakey target");
	527	MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
	528	MODULE_LICENSE("GPL");