[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 up_interval;
	unsigned down_interval;
	unsigned long flags;
	unsigned corrupt_bio_byte;
	unsigned corrupt_bio_rw;
	unsigned corrupt_bio_value;
	blk_opf_t 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.
			 */
			BUILD_BUG_ON(sizeof(fc->corrupt_bio_flags) !=
				     sizeof(unsigned int));
			r = dm_read_arg(_args + 3, as,
				(__force unsigned *)&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 || 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 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 (!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) {
			if (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 (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);
			}
		} 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;

	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,
};

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