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

/*
 * 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 || 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);
	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 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 = (page_address(bio_iter_page(bio, iter))
					 + bio_iter_offset(bio, iter));
			segment[corrupt_bio_byte] = fc->corrupt_bio_value;
			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;

	/* 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 <[email protected]>");
MODULE_LICENSE("GPL");
Commit	Line	Data
3407ef52 JB	1	/*
3407ef52 JB	2	* Copyright (C) 2003 Sistina Software (UK) Limited.
a3998799	3	* Copyright (C) 2004, 2010-2011 Red Hat, Inc. All rights reserved.
3407ef52 JB	4	*
	5	* This file is released under the GPL.
	6	*/
	7
	8	#include <linux/device-mapper.h>
	9
	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>
	15
	16	#define DM_MSG_PREFIX "flakey"
	17
a3998799	18	#define all_corrupt_bio_flags_match(bio, fc) \
1eff9d32	19	(((bio)->bi_opf & (fc)->corrupt_bio_flags) == (fc)->corrupt_bio_flags)
a3998799	20
3407ef52 JB	21	/*
	22	* Flakey: Used for testing only, simulates intermittent,
	23	* catastrophic device failure.
	24	*/
	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;
b26f5e3d	31	unsigned long flags;
a3998799 MS	32	unsigned corrupt_bio_byte;
	33	unsigned corrupt_bio_rw;
	34	unsigned corrupt_bio_value;
	35	unsigned corrupt_bio_flags;
3407ef52 JB	36	};
3407ef52 JB	37
b26f5e3d	38	enum feature_flag_bits {
ef548c55 MS	39	DROP_WRITES,
ef548c55 MS	40	ERROR_WRITES
b26f5e3d MS	41	};
b26f5e3d MS	42
c7cfdf59 MP	43	struct per_bio_data {
	44	bool bio_submitted;
	45	};
	46
b26f5e3d MS	47	static int parse_features(struct dm_arg_set as, struct flakey_c fc,
b26f5e3d MS	48	struct dm_target *ti)
dfd068b0 MS	49	{
	50	int r;
	51	unsigned argc;
	52	const char *arg_name;
	53
5916a22b	54	static const struct dm_arg _args[] = {
a3998799 MS	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"},
dfd068b0 MS	59	};
	60
	61	/* No feature arguments supplied. */
	62	if (!as->argc)
	63	return 0;
	64
	65	r = dm_read_arg_group(_args, as, &argc, &ti->error);
	66	if (r)
a3998799	67	return r;
dfd068b0	68
a3998799	69	while (argc) {
dfd068b0 MS	70	arg_name = dm_shift_arg(as);
	71	argc--;
	72
7690e253 GR	73	if (!arg_name) {
	74	ti->error = "Insufficient feature arguments";
	75	return -EINVAL;
	76	}
	77
b26f5e3d MS	78	/*
	79	* drop_writes
	80	*/
	81	if (!strcasecmp(arg_name, "drop_writes")) {
	82	if (test_and_set_bit(DROP_WRITES, &fc->flags)) {
	83	ti->error = "Feature drop_writes duplicated";
	84	return -EINVAL;
ef548c55 MS	85	} else if (test_bit(ERROR_WRITES, &fc->flags)) {
	86	ti->error = "Feature drop_writes conflicts with feature error_writes";
	87	return -EINVAL;
	88	}
	89
	90	continue;
	91	}
	92
	93	/*
	94	* error_writes
	95	*/
	96	if (!strcasecmp(arg_name, "error_writes")) {
	97	if (test_and_set_bit(ERROR_WRITES, &fc->flags)) {
	98	ti->error = "Feature error_writes duplicated";
	99	return -EINVAL;
	100
	101	} else if (test_bit(DROP_WRITES, &fc->flags)) {
	102	ti->error = "Feature error_writes conflicts with feature drop_writes";
	103	return -EINVAL;
b26f5e3d MS	104	}
	105
	106	continue;
	107	}
	108
a3998799 MS	109	/*
	110	* corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>
	111	*/
	112	if (!strcasecmp(arg_name, "corrupt_bio_byte")) {
68e58a29	113	if (!argc) {
a3998799	114	ti->error = "Feature corrupt_bio_byte requires parameters";
68e58a29 MS	115	return -EINVAL;
68e58a29 MS	116	}
a3998799 MS	117
	118	r = dm_read_arg(_args + 1, as, &fc->corrupt_bio_byte, &ti->error);
	119	if (r)
	120	return r;
	121	argc--;
	122
	123	/*
	124	* Direction r or w?
	125	*/
	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;
	131	else {
	132	ti->error = "Invalid corrupt bio direction (r or w)";
	133	return -EINVAL;
	134	}
	135	argc--;
	136
	137	/*
	138	* Value of byte (0-255) to write in place of correct one.
	139	*/
	140	r = dm_read_arg(_args + 2, as, &fc->corrupt_bio_value, &ti->error);
	141	if (r)
	142	return r;
	143	argc--;
	144
	145	/*
	146	* Only corrupt bios with these flags set.
	147	*/
	148	r = dm_read_arg(_args + 3, as, &fc->corrupt_bio_flags, &ti->error);
	149	if (r)
	150	return r;
	151	argc--;
	152
	153	continue;
	154	}
	155
dfd068b0	156	ti->error = "Unrecognised flakey feature requested";
a3998799	157	return -EINVAL;
dfd068b0 MS	158	}
dfd068b0 MS	159
a3998799 MS	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";
	162	return -EINVAL;
ef548c55 MS	163
	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";
	166	return -EINVAL;
a3998799 MS	167	}
	168
	169	return 0;
dfd068b0 MS	170	}
dfd068b0 MS	171
3407ef52	172	/*
dfd068b0 MS	173	* Construct a flakey mapping:
dfd068b0 MS	174	* <dev_path> <offset> <up interval> <down interval> [<#feature args> [<arg>]*]
b26f5e3d MS	175	*
	176	* Feature args:
	177	* [drop_writes]
a3998799 MS	178	* [corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>]
	179	*
	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.
3407ef52 JB	183	*/
	184	static int flakey_ctr(struct dm_target ti, unsigned int argc, char *argv)
	185	{
5916a22b	186	static const struct dm_arg _args[] = {
dfd068b0 MS	187	{0, UINT_MAX, "Invalid up interval"},
	188	{0, UINT_MAX, "Invalid down interval"},
	189	};
	190
	191	int r;
3407ef52	192	struct flakey_c *fc;
dfd068b0 MS	193	unsigned long long tmpll;
	194	struct dm_arg_set as;
	195	const char *devname;
31998ef1	196	char dummy;
3407ef52	197
dfd068b0 MS	198	as.argc = argc;
	199	as.argv = argv;
	200
	201	if (argc < 4) {
	202	ti->error = "Invalid argument count";
3407ef52 JB	203	return -EINVAL;
	204	}
	205
b26f5e3d	206	fc = kzalloc(sizeof(*fc), GFP_KERNEL);
3407ef52	207	if (!fc) {
75e3a0f5	208	ti->error = "Cannot allocate context";
3407ef52 JB	209	return -ENOMEM;
	210	}
	211	fc->start_time = jiffies;
	212
dfd068b0 MS	213	devname = dm_shift_arg(&as);
dfd068b0 MS	214
e80d1c80	215	r = -EINVAL;
ef87bfc2	216	if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1 \|\| tmpll != (sector_t)tmpll) {
dfd068b0	217	ti->error = "Invalid device sector";
3407ef52 JB	218	goto bad;
3407ef52 JB	219	}
dfd068b0	220	fc->start = tmpll;
3407ef52	221
dfd068b0 MS	222	r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
dfd068b0 MS	223	if (r)
3407ef52	224	goto bad;
3407ef52	225
dfd068b0 MS	226	r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
dfd068b0 MS	227	if (r)
3407ef52	228	goto bad;
3407ef52 JB	229
3407ef52 JB	230	if (!(fc->up_interval + fc->down_interval)) {
dfd068b0	231	ti->error = "Total (up + down) interval is zero";
bff7e067	232	r = -EINVAL;
3407ef52 JB	233	goto bad;
	234	}
	235
	236	if (fc->up_interval + fc->down_interval < fc->up_interval) {
dfd068b0	237	ti->error = "Interval overflow";
bff7e067	238	r = -EINVAL;
3407ef52 JB	239	goto bad;
	240	}
	241
b26f5e3d	242	r = parse_features(&as, fc, ti);
dfd068b0 MS	243	if (r)
	244	goto bad;
	245
e80d1c80 VG	246	r = dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev);
e80d1c80 VG	247	if (r) {
dfd068b0	248	ti->error = "Device lookup failed";
3407ef52 JB	249	goto bad;
	250	}
	251
55a62eef AK	252	ti->num_flush_bios = 1;
55a62eef AK	253	ti->num_discard_bios = 1;
30187e1d	254	ti->per_io_data_size = sizeof(struct per_bio_data);
3407ef52 JB	255	ti->private = fc;
	256	return 0;
	257
	258	bad:
	259	kfree(fc);
e80d1c80	260	return r;
3407ef52 JB	261	}
	262
	263	static void flakey_dtr(struct dm_target *ti)
	264	{
	265	struct flakey_c *fc = ti->private;
	266
	267	dm_put_device(ti, fc->dev);
	268	kfree(fc);
	269	}
	270
	271	static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector)
	272	{
	273	struct flakey_c *fc = ti->private;
	274
30e4171b	275	return fc->start + dm_target_offset(ti, bi_sector);
3407ef52 JB	276	}
	277
	278	static void flakey_map_bio(struct dm_target ti, struct bio bio)
	279	{
	280	struct flakey_c *fc = ti->private;
	281
74d46992	282	bio_set_dev(bio, fc->dev->bdev);
124c4454	283	if (bio_sectors(bio) \|\| bio_op(bio) == REQ_OP_ZONE_RESET)
4f024f37 KO	284	bio->bi_iter.bi_sector =
4f024f37 KO	285	flakey_map_sector(ti, bio->bi_iter.bi_sector);
3407ef52 JB	286	}
3407ef52 JB	287
a3998799 MS	288	static void corrupt_bio_data(struct bio bio, struct flakey_c fc)
a3998799 MS	289	{
a00f5276 ST	290	unsigned int corrupt_bio_byte = fc->corrupt_bio_byte - 1;
	291
	292	struct bvec_iter iter;
	293	struct bio_vec bvec;
	294
	295	if (!bio_has_data(bio))
	296	return;
a3998799 MS	297
a3998799 MS	298	/*
a00f5276 ST	299	* Overwrite the Nth byte of the bio's data, on whichever page
a00f5276 ST	300	* it falls.
a3998799	301	*/
a00f5276 ST	302	bio_for_each_segment(bvec, bio, iter) {
	303	if (bio_iter_len(bio, iter) > corrupt_bio_byte) {
	304	char *segment = (page_address(bio_iter_page(bio, iter))
	305	+ bio_iter_offset(bio, iter));
	306	segment[corrupt_bio_byte] = fc->corrupt_bio_value;
	307	DMDEBUG("Corrupting data bio=%p by writing %u to byte %u "
	308	"(rw=%c bi_opf=%u bi_sector=%llu size=%u)\n",
	309	bio, fc->corrupt_bio_value, fc->corrupt_bio_byte,
	310	(bio_data_dir(bio) == WRITE) ? 'w' : 'r', bio->bi_opf,
	311	(unsigned long long)bio->bi_iter.bi_sector, bio->bi_iter.bi_size);
	312	break;
	313	}
	314	corrupt_bio_byte -= bio_iter_len(bio, iter);
a3998799 MS	315	}
	316	}
	317
7de3ee57	318	static int flakey_map(struct dm_target ti, struct bio bio)
3407ef52 JB	319	{
	320	struct flakey_c *fc = ti->private;
	321	unsigned elapsed;
c7cfdf59 MP	322	struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
c7cfdf59 MP	323	pb->bio_submitted = false;
3407ef52	324
124c4454 DLM	325	/* Do not fail reset zone */
	326	if (bio_op(bio) == REQ_OP_ZONE_RESET)
	327	goto map_bio;
	328
3407ef52 JB	329	/* Are we alive ? */
3407ef52 JB	330	elapsed = (jiffies - fc->start_time) / HZ;
b26f5e3d	331	if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
a3998799 MS	332	/*
	333	* Flag this bio as submitted while down.
	334	*/
c7cfdf59	335	pb->bio_submitted = true;
a3998799 MS	336
a3998799 MS	337	/*
ef548c55	338	* Error reads if neither corrupt_bio_byte or drop_writes or error_writes are set.
299f6230	339	* Otherwise, flakey_end_io() will decide if the reads should be modified.
a3998799	340	*/
99f3c90d	341	if (bio_data_dir(bio) == READ) {
ef548c55 MS	342	if (!fc->corrupt_bio_byte && !test_bit(DROP_WRITES, &fc->flags) &&
ef548c55 MS	343	!test_bit(ERROR_WRITES, &fc->flags))
846785e6	344	return DM_MAPIO_KILL;
299f6230	345	goto map_bio;
99f3c90d	346	}
b26f5e3d MS	347
b26f5e3d MS	348	/*
ef548c55	349	* Drop or error writes?
b26f5e3d MS	350	*/
b26f5e3d MS	351	if (test_bit(DROP_WRITES, &fc->flags)) {
4246a0b6	352	bio_endio(bio);
a3998799 MS	353	return DM_MAPIO_SUBMITTED;
a3998799 MS	354	}
ef548c55 MS	355	else if (test_bit(ERROR_WRITES, &fc->flags)) {
	356	bio_io_error(bio);
	357	return DM_MAPIO_SUBMITTED;
	358	}
a3998799 MS	359
	360	/*
	361	* Corrupt matching writes.
	362	*/
	363	if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == WRITE)) {
	364	if (all_corrupt_bio_flags_match(bio, fc))
	365	corrupt_bio_data(bio, fc);
b26f5e3d MS	366	goto map_bio;
	367	}
	368
	369	/*
a3998799	370	* By default, error all I/O.
b26f5e3d	371	*/
846785e6	372	return DM_MAPIO_KILL;
b26f5e3d	373	}
3407ef52	374
b26f5e3d	375	map_bio:
3407ef52 JB	376	flakey_map_bio(ti, bio);
	377
	378	return DM_MAPIO_REMAPPED;
	379	}
	380
4e4cbee9	381	static int flakey_end_io(struct dm_target ti, struct bio bio,
124c4454	382	blk_status_t *error)
a3998799 MS	383	{
a3998799 MS	384	struct flakey_c *fc = ti->private;
c7cfdf59	385	struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
a3998799	386
124c4454 DLM	387	if (bio_op(bio) == REQ_OP_ZONE_RESET)
	388	return DM_ENDIO_DONE;
	389
1be56909	390	if (!*error && pb->bio_submitted && (bio_data_dir(bio) == READ)) {
299f6230 MS	391	if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == READ) &&
	392	all_corrupt_bio_flags_match(bio, fc)) {
	393	/*
	394	* Corrupt successful matching READs while in down state.
	395	*/
99f3c90d	396	corrupt_bio_data(bio, fc);
299f6230	397
ef548c55 MS	398	} else if (!test_bit(DROP_WRITES, &fc->flags) &&
ef548c55 MS	399	!test_bit(ERROR_WRITES, &fc->flags)) {
299f6230 MS	400	/*
299f6230 MS	401	* Error read during the down_interval if drop_writes
ef548c55	402	* and error_writes were not configured.
299f6230	403	*/
4e4cbee9	404	*error = BLK_STS_IOERR;
299f6230	405	}
99f3c90d	406	}
a3998799	407
1be56909	408	return DM_ENDIO_DONE;
a3998799 MS	409	}
a3998799 MS	410
fd7c092e MP	411	static void flakey_status(struct dm_target *ti, status_type_t type,
fd7c092e MP	412	unsigned status_flags, char *result, unsigned maxlen)
3407ef52	413	{
b26f5e3d	414	unsigned sz = 0;
3407ef52	415	struct flakey_c *fc = ti->private;
ef548c55	416	unsigned drop_writes, error_writes;
3407ef52 JB	417
	418	switch (type) {
	419	case STATUSTYPE_INFO:
	420	result[0] = '\0';
	421	break;
	422
	423	case STATUSTYPE_TABLE:
b26f5e3d MS	424	DMEMIT("%s %llu %u %u ", fc->dev->name,
	425	(unsigned long long)fc->start, fc->up_interval,
	426	fc->down_interval);
	427
	428	drop_writes = test_bit(DROP_WRITES, &fc->flags);
ef548c55 MS	429	error_writes = test_bit(ERROR_WRITES, &fc->flags);
ef548c55 MS	430	DMEMIT("%u ", drop_writes + error_writes + (fc->corrupt_bio_byte > 0) * 5);
a3998799	431
b26f5e3d MS	432	if (drop_writes)
b26f5e3d MS	433	DMEMIT("drop_writes ");
ef548c55 MS	434	else if (error_writes)
ef548c55 MS	435	DMEMIT("error_writes ");
a3998799 MS	436
	437	if (fc->corrupt_bio_byte)
	438	DMEMIT("corrupt_bio_byte %u %c %u %u ",
	439	fc->corrupt_bio_byte,
	440	(fc->corrupt_bio_rw == WRITE) ? 'w' : 'r',
	441	fc->corrupt_bio_value, fc->corrupt_bio_flags);
	442
3407ef52 JB	443	break;
3407ef52 JB	444	}
3407ef52 JB	445	}
3407ef52 JB	446
5bd5e8d8	447	static int flakey_prepare_ioctl(struct dm_target ti, struct block_device *bdev)
3407ef52 JB	448	{
3407ef52 JB	449	struct flakey_c *fc = ti->private;
e56f81e0 CH	450
e56f81e0 CH	451	*bdev = fc->dev->bdev;
3407ef52	452
ec8013be PB	453	/*
	454	* Only pass ioctls through if the device sizes match exactly.
	455	*/
	456	if (fc->start \|\|
e56f81e0 CH	457	ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT)
	458	return 1;
	459	return 0;
3407ef52 JB	460	}
3407ef52 JB	461
e76239a3 CH	462	#ifdef CONFIG_BLK_DEV_ZONED
	463	static int flakey_report_zones(struct dm_target *ti, sector_t sector,
	464	struct blk_zone zones, unsigned int nr_zones,
	465	gfp_t gfp_mask)
	466	{
	467	struct flakey_c *fc = ti->private;
	468	int ret;
	469
	470	/* Do report and remap it */
	471	ret = blkdev_report_zones(fc->dev->bdev, flakey_map_sector(ti, sector),
	472	zones, nr_zones, gfp_mask);
	473	if (ret != 0)
	474	return ret;
	475
	476	if (*nr_zones)
	477	dm_remap_zone_report(ti, fc->start, zones, nr_zones);
	478	return 0;
	479	}
	480	#endif
	481
3407ef52 JB	482	static int flakey_iterate_devices(struct dm_target ti, iterate_devices_callout_fn fn, void data)
	483	{
	484	struct flakey_c *fc = ti->private;
	485
	486	return fn(ti, fc->dev, fc->start, ti->len, data);
	487	}
	488
	489	static struct target_type flakey_target = {
	490	.name = "flakey",
124c4454	491	.version = {1, 5, 0},
118aa47c	492	#ifdef CONFIG_BLK_DEV_ZONED
124c4454	493	.features = DM_TARGET_ZONED_HM,
e76239a3	494	.report_zones = flakey_report_zones,
118aa47c	495	#endif
3407ef52 JB	496	.module = THIS_MODULE,
	497	.ctr = flakey_ctr,
	498	.dtr = flakey_dtr,
	499	.map = flakey_map,
a3998799	500	.end_io = flakey_end_io,
3407ef52	501	.status = flakey_status,
e56f81e0	502	.prepare_ioctl = flakey_prepare_ioctl,
3407ef52 JB	503	.iterate_devices = flakey_iterate_devices,
	504	};
	505
	506	static int __init dm_flakey_init(void)
	507	{
	508	int r = dm_register_target(&flakey_target);
	509
	510	if (r < 0)
	511	DMERR("register failed %d", r);
	512
	513	return r;
	514	}
	515
	516	static void __exit dm_flakey_exit(void)
	517	{
	518	dm_unregister_target(&flakey_target);
	519	}
	520
	521	/* Module hooks */
	522	module_init(dm_flakey_init);
	523	module_exit(dm_flakey_exit);
	524
	525	MODULE_DESCRIPTION(DM_NAME " flakey target");
	526	MODULE_AUTHOR("Joe Thornber <[email protected]>");
	527	MODULE_LICENSE("GPL");