[deliverable/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_rw & (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
};

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 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--;

		/*
		 * 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;
			}

			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;
	}

	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 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;

	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 linear context";
		return -ENOMEM;
	}
	fc->start_time = jiffies;

	devname = dm_shift_arg(&as);

	if (sscanf(dm_shift_arg(&as), "%llu", &tmpll) != 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";
		goto bad;
	}

	if (fc->up_interval + fc->down_interval < fc->up_interval) {
		ti->error = "Interval overflow";
		goto bad;
	}

	r = parse_features(&as, fc, ti);
	if (r)
		goto bad;

	if (dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev)) {
		ti->error = "Device lookup failed";
		goto bad;
	}

	ti->num_flush_requests = 1;
	ti->num_discard_requests = 1;
	ti->private = fc;
	return 0;

bad:
	kfree(fc);
	return -EINVAL;
}

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->bi_bdev = fc->dev->bdev;
	if (bio_sectors(bio))
		bio->bi_sector = flakey_map_sector(ti, bio->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_rw=%lu 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_rw, (unsigned long long)bio->bi_sector, bio_bytes);
	}
}

static int flakey_map(struct dm_target *ti, struct bio *bio,
		      union map_info *map_context)
{
	struct flakey_c *fc = ti->private;
	unsigned elapsed;

	/* 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.
		 */
		map_context->ll = 1;

		/*
		 * Map reads as normal.
		 */
		if (bio_data_dir(bio) == READ)
			goto map_bio;

		/*
		 * Drop writes?
		 */
		if (test_bit(DROP_WRITES, &fc->flags)) {
			bio_endio(bio, 0);
			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 -EIO;
	}

map_bio:
	flakey_map_bio(ti, bio);

	return DM_MAPIO_REMAPPED;
}

static int flakey_end_io(struct dm_target *ti, struct bio *bio,
			 int error, union map_info *map_context)
{
	struct flakey_c *fc = ti->private;
	unsigned bio_submitted_while_down = map_context->ll;

	/*
	 * Corrupt successful READs while in down state.
	 * If flags were specified, only corrupt those that match.
	 */
	if (!error && bio_submitted_while_down &&
	    (bio_data_dir(bio) == READ) && (fc->corrupt_bio_rw == READ) &&
	    all_corrupt_bio_flags_match(bio, fc))
		corrupt_bio_data(bio, fc);

	return error;
}

static int flakey_status(struct dm_target *ti, status_type_t type,
			 char *result, unsigned int maxlen)
{
	unsigned sz = 0;
	struct flakey_c *fc = ti->private;
	unsigned drop_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);
		DMEMIT("%u ", drop_writes + (fc->corrupt_bio_byte > 0) * 5);

		if (drop_writes)
			DMEMIT("drop_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;
	}
	return 0;
}

static int flakey_ioctl(struct dm_target *ti, unsigned int cmd, unsigned long arg)
{
	struct flakey_c *fc = ti->private;

	return __blkdev_driver_ioctl(fc->dev->bdev, fc->dev->mode, cmd, arg);
}

static int flakey_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
			struct bio_vec *biovec, int max_size)
{
	struct flakey_c *fc = ti->private;
	struct request_queue *q = bdev_get_queue(fc->dev->bdev);

	if (!q->merge_bvec_fn)
		return max_size;

	bvm->bi_bdev = fc->dev->bdev;
	bvm->bi_sector = flakey_map_sector(ti, bvm->bi_sector);

	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
}

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, 2, 0},
	.module = THIS_MODULE,
	.ctr    = flakey_ctr,
	.dtr    = flakey_dtr,
	.map    = flakey_map,
	.end_io = flakey_end_io,
	.status = flakey_status,
	.ioctl	= flakey_ioctl,
	.merge	= flakey_merge,
	.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
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 MS	18	#define all_corrupt_bio_flags_match(bio, fc) \
	19	(((bio)->bi_rw & (fc)->corrupt_bio_flags) == (fc)->corrupt_bio_flags)
	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 MS	38	enum feature_flag_bits {
	39	DROP_WRITES
	40	};
	41
	42	static int parse_features(struct dm_arg_set as, struct flakey_c fc,
	43	struct dm_target *ti)
dfd068b0 MS	44	{
	45	int r;
	46	unsigned argc;
	47	const char *arg_name;
	48
	49	static struct dm_arg _args[] = {
a3998799 MS	50	{0, 6, "Invalid number of feature args"},
	51	{1, UINT_MAX, "Invalid corrupt bio byte"},
	52	{0, 255, "Invalid corrupt value to write into bio byte (0-255)"},
	53	{0, UINT_MAX, "Invalid corrupt bio flags mask"},
dfd068b0 MS	54	};
	55
	56	/* No feature arguments supplied. */
	57	if (!as->argc)
	58	return 0;
	59
	60	r = dm_read_arg_group(_args, as, &argc, &ti->error);
	61	if (r)
a3998799	62	return r;
dfd068b0	63
a3998799	64	while (argc) {
dfd068b0 MS	65	arg_name = dm_shift_arg(as);
	66	argc--;
	67
b26f5e3d MS	68	/*
	69	* drop_writes
	70	*/
	71	if (!strcasecmp(arg_name, "drop_writes")) {
	72	if (test_and_set_bit(DROP_WRITES, &fc->flags)) {
	73	ti->error = "Feature drop_writes duplicated";
	74	return -EINVAL;
	75	}
	76
	77	continue;
	78	}
	79
a3998799 MS	80	/*
	81	* corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>
	82	*/
	83	if (!strcasecmp(arg_name, "corrupt_bio_byte")) {
68e58a29	84	if (!argc) {
a3998799	85	ti->error = "Feature corrupt_bio_byte requires parameters";
68e58a29 MS	86	return -EINVAL;
68e58a29 MS	87	}
a3998799 MS	88
	89	r = dm_read_arg(_args + 1, as, &fc->corrupt_bio_byte, &ti->error);
	90	if (r)
	91	return r;
	92	argc--;
	93
	94	/*
	95	* Direction r or w?
	96	*/
	97	arg_name = dm_shift_arg(as);
	98	if (!strcasecmp(arg_name, "w"))
	99	fc->corrupt_bio_rw = WRITE;
	100	else if (!strcasecmp(arg_name, "r"))
	101	fc->corrupt_bio_rw = READ;
	102	else {
	103	ti->error = "Invalid corrupt bio direction (r or w)";
	104	return -EINVAL;
	105	}
	106	argc--;
	107
	108	/*
	109	* Value of byte (0-255) to write in place of correct one.
	110	*/
	111	r = dm_read_arg(_args + 2, as, &fc->corrupt_bio_value, &ti->error);
	112	if (r)
	113	return r;
	114	argc--;
	115
	116	/*
	117	* Only corrupt bios with these flags set.
	118	*/
	119	r = dm_read_arg(_args + 3, as, &fc->corrupt_bio_flags, &ti->error);
	120	if (r)
	121	return r;
	122	argc--;
	123
	124	continue;
	125	}
	126
dfd068b0	127	ti->error = "Unrecognised flakey feature requested";
a3998799	128	return -EINVAL;
dfd068b0 MS	129	}
dfd068b0 MS	130
a3998799 MS	131	if (test_bit(DROP_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) {
	132	ti->error = "drop_writes is incompatible with corrupt_bio_byte with the WRITE flag set";
	133	return -EINVAL;
	134	}
	135
	136	return 0;
dfd068b0 MS	137	}
dfd068b0 MS	138
3407ef52	139	/*
dfd068b0 MS	140	* Construct a flakey mapping:
dfd068b0 MS	141	* <dev_path> <offset> <up interval> <down interval> [<#feature args> [<arg>]*]
b26f5e3d MS	142	*
	143	* Feature args:
	144	* [drop_writes]
a3998799 MS	145	* [corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>]
	146	*
	147	* Nth_byte starts from 1 for the first byte.
	148	* Direction is r for READ or w for WRITE.
	149	* bio_flags is ignored if 0.
3407ef52 JB	150	*/
	151	static int flakey_ctr(struct dm_target ti, unsigned int argc, char *argv)
	152	{
dfd068b0 MS	153	static struct dm_arg _args[] = {
	154	{0, UINT_MAX, "Invalid up interval"},
	155	{0, UINT_MAX, "Invalid down interval"},
	156	};
	157
	158	int r;
3407ef52	159	struct flakey_c *fc;
dfd068b0 MS	160	unsigned long long tmpll;
	161	struct dm_arg_set as;
	162	const char *devname;
3407ef52	163
dfd068b0 MS	164	as.argc = argc;
	165	as.argv = argv;
	166
	167	if (argc < 4) {
	168	ti->error = "Invalid argument count";
3407ef52 JB	169	return -EINVAL;
	170	}
	171
b26f5e3d	172	fc = kzalloc(sizeof(*fc), GFP_KERNEL);
3407ef52	173	if (!fc) {
dfd068b0	174	ti->error = "Cannot allocate linear context";
3407ef52 JB	175	return -ENOMEM;
	176	}
	177	fc->start_time = jiffies;
	178
dfd068b0 MS	179	devname = dm_shift_arg(&as);
	180
	181	if (sscanf(dm_shift_arg(&as), "%llu", &tmpll) != 1) {
	182	ti->error = "Invalid device sector";
3407ef52 JB	183	goto bad;
3407ef52 JB	184	}
dfd068b0	185	fc->start = tmpll;
3407ef52	186
dfd068b0 MS	187	r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
dfd068b0 MS	188	if (r)
3407ef52	189	goto bad;
3407ef52	190
dfd068b0 MS	191	r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
dfd068b0 MS	192	if (r)
3407ef52	193	goto bad;
3407ef52 JB	194
3407ef52 JB	195	if (!(fc->up_interval + fc->down_interval)) {
dfd068b0	196	ti->error = "Total (up + down) interval is zero";
3407ef52 JB	197	goto bad;
	198	}
	199
	200	if (fc->up_interval + fc->down_interval < fc->up_interval) {
dfd068b0	201	ti->error = "Interval overflow";
3407ef52 JB	202	goto bad;
	203	}
	204
b26f5e3d	205	r = parse_features(&as, fc, ti);
dfd068b0 MS	206	if (r)
	207	goto bad;
	208
	209	if (dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev)) {
	210	ti->error = "Device lookup failed";
3407ef52 JB	211	goto bad;
	212	}
	213
	214	ti->num_flush_requests = 1;
30e4171b	215	ti->num_discard_requests = 1;
3407ef52 JB	216	ti->private = fc;
	217	return 0;
	218
	219	bad:
	220	kfree(fc);
	221	return -EINVAL;
	222	}
	223
	224	static void flakey_dtr(struct dm_target *ti)
	225	{
	226	struct flakey_c *fc = ti->private;
	227
	228	dm_put_device(ti, fc->dev);
	229	kfree(fc);
	230	}
	231
	232	static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector)
	233	{
	234	struct flakey_c *fc = ti->private;
	235
30e4171b	236	return fc->start + dm_target_offset(ti, bi_sector);
3407ef52 JB	237	}
	238
	239	static void flakey_map_bio(struct dm_target ti, struct bio bio)
	240	{
	241	struct flakey_c *fc = ti->private;
	242
	243	bio->bi_bdev = fc->dev->bdev;
	244	if (bio_sectors(bio))
	245	bio->bi_sector = flakey_map_sector(ti, bio->bi_sector);
	246	}
	247
a3998799 MS	248	static void corrupt_bio_data(struct bio bio, struct flakey_c fc)
	249	{
	250	unsigned bio_bytes = bio_cur_bytes(bio);
	251	char *data = bio_data(bio);
	252
	253	/*
	254	* Overwrite the Nth byte of the data returned.
	255	*/
	256	if (data && bio_bytes >= fc->corrupt_bio_byte) {
	257	data[fc->corrupt_bio_byte - 1] = fc->corrupt_bio_value;
	258
	259	DMDEBUG("Corrupting data bio=%p by writing %u to byte %u "
	260	"(rw=%c bi_rw=%lu bi_sector=%llu cur_bytes=%u)\n",
	261	bio, fc->corrupt_bio_value, fc->corrupt_bio_byte,
	262	(bio_data_dir(bio) == WRITE) ? 'w' : 'r',
	263	bio->bi_rw, (unsigned long long)bio->bi_sector, bio_bytes);
	264	}
	265	}
	266
3407ef52 JB	267	static int flakey_map(struct dm_target ti, struct bio bio,
	268	union map_info *map_context)
	269	{
	270	struct flakey_c *fc = ti->private;
	271	unsigned elapsed;
	272
	273	/* Are we alive ? */
	274	elapsed = (jiffies - fc->start_time) / HZ;
b26f5e3d	275	if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
a3998799 MS	276	/*
	277	* Flag this bio as submitted while down.
	278	*/
	279	map_context->ll = 1;
	280
	281	/*
	282	* Map reads as normal.
	283	*/
	284	if (bio_data_dir(bio) == READ)
	285	goto map_bio;
b26f5e3d MS	286
b26f5e3d MS	287	/*
a3998799	288	* Drop writes?
b26f5e3d MS	289	*/
b26f5e3d MS	290	if (test_bit(DROP_WRITES, &fc->flags)) {
a3998799 MS	291	bio_endio(bio, 0);
	292	return DM_MAPIO_SUBMITTED;
	293	}
	294
	295	/*
	296	* Corrupt matching writes.
	297	*/
	298	if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == WRITE)) {
	299	if (all_corrupt_bio_flags_match(bio, fc))
	300	corrupt_bio_data(bio, fc);
b26f5e3d MS	301	goto map_bio;
	302	}
	303
	304	/*
a3998799	305	* By default, error all I/O.
b26f5e3d	306	*/
3407ef52	307	return -EIO;
b26f5e3d	308	}
3407ef52	309
b26f5e3d	310	map_bio:
3407ef52 JB	311	flakey_map_bio(ti, bio);
	312
	313	return DM_MAPIO_REMAPPED;
	314	}
	315
a3998799 MS	316	static int flakey_end_io(struct dm_target ti, struct bio bio,
	317	int error, union map_info *map_context)
	318	{
	319	struct flakey_c *fc = ti->private;
	320	unsigned bio_submitted_while_down = map_context->ll;
	321
	322	/*
	323	* Corrupt successful READs while in down state.
	324	* If flags were specified, only corrupt those that match.
	325	*/
	326	if (!error && bio_submitted_while_down &&
	327	(bio_data_dir(bio) == READ) && (fc->corrupt_bio_rw == READ) &&
	328	all_corrupt_bio_flags_match(bio, fc))
	329	corrupt_bio_data(bio, fc);
	330
	331	return error;
	332	}
	333
3407ef52 JB	334	static int flakey_status(struct dm_target *ti, status_type_t type,
	335	char *result, unsigned int maxlen)
	336	{
b26f5e3d	337	unsigned sz = 0;
3407ef52	338	struct flakey_c *fc = ti->private;
b26f5e3d	339	unsigned drop_writes;
3407ef52 JB	340
	341	switch (type) {
	342	case STATUSTYPE_INFO:
	343	result[0] = '\0';
	344	break;
	345
	346	case STATUSTYPE_TABLE:
b26f5e3d MS	347	DMEMIT("%s %llu %u %u ", fc->dev->name,
	348	(unsigned long long)fc->start, fc->up_interval,
	349	fc->down_interval);
	350
	351	drop_writes = test_bit(DROP_WRITES, &fc->flags);
a3998799 MS	352	DMEMIT("%u ", drop_writes + (fc->corrupt_bio_byte > 0) * 5);
a3998799 MS	353
b26f5e3d MS	354	if (drop_writes)
b26f5e3d MS	355	DMEMIT("drop_writes ");
a3998799 MS	356
	357	if (fc->corrupt_bio_byte)
	358	DMEMIT("corrupt_bio_byte %u %c %u %u ",
	359	fc->corrupt_bio_byte,
	360	(fc->corrupt_bio_rw == WRITE) ? 'w' : 'r',
	361	fc->corrupt_bio_value, fc->corrupt_bio_flags);
	362
3407ef52 JB	363	break;
	364	}
	365	return 0;
	366	}
	367
	368	static int flakey_ioctl(struct dm_target *ti, unsigned int cmd, unsigned long arg)
	369	{
	370	struct flakey_c *fc = ti->private;
	371
	372	return __blkdev_driver_ioctl(fc->dev->bdev, fc->dev->mode, cmd, arg);
	373	}
	374
	375	static int flakey_merge(struct dm_target ti, struct bvec_merge_data bvm,
	376	struct bio_vec *biovec, int max_size)
	377	{
	378	struct flakey_c *fc = ti->private;
	379	struct request_queue *q = bdev_get_queue(fc->dev->bdev);
	380
	381	if (!q->merge_bvec_fn)
	382	return max_size;
	383
	384	bvm->bi_bdev = fc->dev->bdev;
	385	bvm->bi_sector = flakey_map_sector(ti, bvm->bi_sector);
	386
	387	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
	388	}
	389
	390	static int flakey_iterate_devices(struct dm_target ti, iterate_devices_callout_fn fn, void data)
	391	{
	392	struct flakey_c *fc = ti->private;
	393
	394	return fn(ti, fc->dev, fc->start, ti->len, data);
	395	}
	396
	397	static struct target_type flakey_target = {
	398	.name = "flakey",
dfd068b0	399	.version = {1, 2, 0},
3407ef52 JB	400	.module = THIS_MODULE,
	401	.ctr = flakey_ctr,
	402	.dtr = flakey_dtr,
	403	.map = flakey_map,
a3998799	404	.end_io = flakey_end_io,
3407ef52 JB	405	.status = flakey_status,
	406	.ioctl = flakey_ioctl,
	407	.merge = flakey_merge,
	408	.iterate_devices = flakey_iterate_devices,
	409	};
	410
	411	static int __init dm_flakey_init(void)
	412	{
	413	int r = dm_register_target(&flakey_target);
	414
	415	if (r < 0)
	416	DMERR("register failed %d", r);
	417
	418	return r;
	419	}
	420
	421	static void __exit dm_flakey_exit(void)
	422	{
	423	dm_unregister_target(&flakey_target);
	424	}
	425
	426	/* Module hooks */
	427	module_init(dm_flakey_init);
	428	module_exit(dm_flakey_exit);
	429
	430	MODULE_DESCRIPTION(DM_NAME " flakey target");
	431	MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
	432	MODULE_LICENSE("GPL");