[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";

			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")) {
	84	if (!argc)
	85	ti->error = "Feature corrupt_bio_byte requires parameters";
	86
	87	r = dm_read_arg(_args + 1, as, &fc->corrupt_bio_byte, &ti->error);
	88	if (r)
	89	return r;
	90	argc--;
	91
	92	/*
	93	* Direction r or w?
	94	*/
	95	arg_name = dm_shift_arg(as);
	96	if (!strcasecmp(arg_name, "w"))
	97	fc->corrupt_bio_rw = WRITE;
	98	else if (!strcasecmp(arg_name, "r"))
	99	fc->corrupt_bio_rw = READ;
	100	else {
	101	ti->error = "Invalid corrupt bio direction (r or w)";
	102	return -EINVAL;
	103	}
	104	argc--;
	105
	106	/*
	107	* Value of byte (0-255) to write in place of correct one.
	108	*/
	109	r = dm_read_arg(_args + 2, as, &fc->corrupt_bio_value, &ti->error);
	110	if (r)
	111	return r;
	112	argc--;
	113
	114	/*
	115	* Only corrupt bios with these flags set.
	116	*/
	117	r = dm_read_arg(_args + 3, as, &fc->corrupt_bio_flags, &ti->error);
	118	if (r)
	119	return r;
	120	argc--;
	121
	122	continue;
	123	}
	124
dfd068b0	125	ti->error = "Unrecognised flakey feature requested";
a3998799	126	return -EINVAL;
dfd068b0 MS	127	}
dfd068b0 MS	128
a3998799 MS	129	if (test_bit(DROP_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) {
	130	ti->error = "drop_writes is incompatible with corrupt_bio_byte with the WRITE flag set";
	131	return -EINVAL;
	132	}
	133
	134	return 0;
dfd068b0 MS	135	}
dfd068b0 MS	136
3407ef52	137	/*
dfd068b0 MS	138	* Construct a flakey mapping:
dfd068b0 MS	139	* <dev_path> <offset> <up interval> <down interval> [<#feature args> [<arg>]*]
b26f5e3d MS	140	*
	141	* Feature args:
	142	* [drop_writes]
a3998799 MS	143	* [corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>]
	144	*
	145	* Nth_byte starts from 1 for the first byte.
	146	* Direction is r for READ or w for WRITE.
	147	* bio_flags is ignored if 0.
3407ef52 JB	148	*/
	149	static int flakey_ctr(struct dm_target ti, unsigned int argc, char *argv)
	150	{
dfd068b0 MS	151	static struct dm_arg _args[] = {
	152	{0, UINT_MAX, "Invalid up interval"},
	153	{0, UINT_MAX, "Invalid down interval"},
	154	};
	155
	156	int r;
3407ef52	157	struct flakey_c *fc;
dfd068b0 MS	158	unsigned long long tmpll;
	159	struct dm_arg_set as;
	160	const char *devname;
3407ef52	161
dfd068b0 MS	162	as.argc = argc;
	163	as.argv = argv;
	164
	165	if (argc < 4) {
	166	ti->error = "Invalid argument count";
3407ef52 JB	167	return -EINVAL;
	168	}
	169
b26f5e3d	170	fc = kzalloc(sizeof(*fc), GFP_KERNEL);
3407ef52	171	if (!fc) {
dfd068b0	172	ti->error = "Cannot allocate linear context";
3407ef52 JB	173	return -ENOMEM;
	174	}
	175	fc->start_time = jiffies;
	176
dfd068b0 MS	177	devname = dm_shift_arg(&as);
	178
	179	if (sscanf(dm_shift_arg(&as), "%llu", &tmpll) != 1) {
	180	ti->error = "Invalid device sector";
3407ef52 JB	181	goto bad;
3407ef52 JB	182	}
dfd068b0	183	fc->start = tmpll;
3407ef52	184
dfd068b0 MS	185	r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
dfd068b0 MS	186	if (r)
3407ef52	187	goto bad;
3407ef52	188
dfd068b0 MS	189	r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
dfd068b0 MS	190	if (r)
3407ef52	191	goto bad;
3407ef52 JB	192
3407ef52 JB	193	if (!(fc->up_interval + fc->down_interval)) {
dfd068b0	194	ti->error = "Total (up + down) interval is zero";
3407ef52 JB	195	goto bad;
	196	}
	197
	198	if (fc->up_interval + fc->down_interval < fc->up_interval) {
dfd068b0	199	ti->error = "Interval overflow";
3407ef52 JB	200	goto bad;
	201	}
	202
b26f5e3d	203	r = parse_features(&as, fc, ti);
dfd068b0 MS	204	if (r)
	205	goto bad;
	206
	207	if (dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev)) {
	208	ti->error = "Device lookup failed";
3407ef52 JB	209	goto bad;
	210	}
	211
	212	ti->num_flush_requests = 1;
30e4171b	213	ti->num_discard_requests = 1;
3407ef52 JB	214	ti->private = fc;
	215	return 0;
	216
	217	bad:
	218	kfree(fc);
	219	return -EINVAL;
	220	}
	221
	222	static void flakey_dtr(struct dm_target *ti)
	223	{
	224	struct flakey_c *fc = ti->private;
	225
	226	dm_put_device(ti, fc->dev);
	227	kfree(fc);
	228	}
	229
	230	static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector)
	231	{
	232	struct flakey_c *fc = ti->private;
	233
30e4171b	234	return fc->start + dm_target_offset(ti, bi_sector);
3407ef52 JB	235	}
	236
	237	static void flakey_map_bio(struct dm_target ti, struct bio bio)
	238	{
	239	struct flakey_c *fc = ti->private;
	240
	241	bio->bi_bdev = fc->dev->bdev;
	242	if (bio_sectors(bio))
	243	bio->bi_sector = flakey_map_sector(ti, bio->bi_sector);
	244	}
	245
a3998799 MS	246	static void corrupt_bio_data(struct bio bio, struct flakey_c fc)
	247	{
	248	unsigned bio_bytes = bio_cur_bytes(bio);
	249	char *data = bio_data(bio);
	250
	251	/*
	252	* Overwrite the Nth byte of the data returned.
	253	*/
	254	if (data && bio_bytes >= fc->corrupt_bio_byte) {
	255	data[fc->corrupt_bio_byte - 1] = fc->corrupt_bio_value;
	256
	257	DMDEBUG("Corrupting data bio=%p by writing %u to byte %u "
	258	"(rw=%c bi_rw=%lu bi_sector=%llu cur_bytes=%u)\n",
	259	bio, fc->corrupt_bio_value, fc->corrupt_bio_byte,
	260	(bio_data_dir(bio) == WRITE) ? 'w' : 'r',
	261	bio->bi_rw, (unsigned long long)bio->bi_sector, bio_bytes);
	262	}
	263	}
	264
3407ef52 JB	265	static int flakey_map(struct dm_target ti, struct bio bio,
	266	union map_info *map_context)
	267	{
	268	struct flakey_c *fc = ti->private;
	269	unsigned elapsed;
	270
	271	/* Are we alive ? */
	272	elapsed = (jiffies - fc->start_time) / HZ;
b26f5e3d	273	if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
a3998799 MS	274	/*
	275	* Flag this bio as submitted while down.
	276	*/
	277	map_context->ll = 1;
	278
	279	/*
	280	* Map reads as normal.
	281	*/
	282	if (bio_data_dir(bio) == READ)
	283	goto map_bio;
b26f5e3d MS	284
b26f5e3d MS	285	/*
a3998799	286	* Drop writes?
b26f5e3d MS	287	*/
b26f5e3d MS	288	if (test_bit(DROP_WRITES, &fc->flags)) {
a3998799 MS	289	bio_endio(bio, 0);
	290	return DM_MAPIO_SUBMITTED;
	291	}
	292
	293	/*
	294	* Corrupt matching writes.
	295	*/
	296	if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == WRITE)) {
	297	if (all_corrupt_bio_flags_match(bio, fc))
	298	corrupt_bio_data(bio, fc);
b26f5e3d MS	299	goto map_bio;
	300	}
	301
	302	/*
a3998799	303	* By default, error all I/O.
b26f5e3d	304	*/
3407ef52	305	return -EIO;
b26f5e3d	306	}
3407ef52	307
b26f5e3d	308	map_bio:
3407ef52 JB	309	flakey_map_bio(ti, bio);
	310
	311	return DM_MAPIO_REMAPPED;
	312	}
	313
a3998799 MS	314	static int flakey_end_io(struct dm_target ti, struct bio bio,
	315	int error, union map_info *map_context)
	316	{
	317	struct flakey_c *fc = ti->private;
	318	unsigned bio_submitted_while_down = map_context->ll;
	319
	320	/*
	321	* Corrupt successful READs while in down state.
	322	* If flags were specified, only corrupt those that match.
	323	*/
	324	if (!error && bio_submitted_while_down &&
	325	(bio_data_dir(bio) == READ) && (fc->corrupt_bio_rw == READ) &&
	326	all_corrupt_bio_flags_match(bio, fc))
	327	corrupt_bio_data(bio, fc);
	328
	329	return error;
	330	}
	331
3407ef52 JB	332	static int flakey_status(struct dm_target *ti, status_type_t type,
	333	char *result, unsigned int maxlen)
	334	{
b26f5e3d	335	unsigned sz = 0;
3407ef52	336	struct flakey_c *fc = ti->private;
b26f5e3d	337	unsigned drop_writes;
3407ef52 JB	338
	339	switch (type) {
	340	case STATUSTYPE_INFO:
	341	result[0] = '\0';
	342	break;
	343
	344	case STATUSTYPE_TABLE:
b26f5e3d MS	345	DMEMIT("%s %llu %u %u ", fc->dev->name,
	346	(unsigned long long)fc->start, fc->up_interval,
	347	fc->down_interval);
	348
	349	drop_writes = test_bit(DROP_WRITES, &fc->flags);
a3998799 MS	350	DMEMIT("%u ", drop_writes + (fc->corrupt_bio_byte > 0) * 5);
a3998799 MS	351
b26f5e3d MS	352	if (drop_writes)
b26f5e3d MS	353	DMEMIT("drop_writes ");
a3998799 MS	354
	355	if (fc->corrupt_bio_byte)
	356	DMEMIT("corrupt_bio_byte %u %c %u %u ",
	357	fc->corrupt_bio_byte,
	358	(fc->corrupt_bio_rw == WRITE) ? 'w' : 'r',
	359	fc->corrupt_bio_value, fc->corrupt_bio_flags);
	360
3407ef52 JB	361	break;
	362	}
	363	return 0;
	364	}
	365
	366	static int flakey_ioctl(struct dm_target *ti, unsigned int cmd, unsigned long arg)
	367	{
	368	struct flakey_c *fc = ti->private;
	369
	370	return __blkdev_driver_ioctl(fc->dev->bdev, fc->dev->mode, cmd, arg);
	371	}
	372
	373	static int flakey_merge(struct dm_target ti, struct bvec_merge_data bvm,
	374	struct bio_vec *biovec, int max_size)
	375	{
	376	struct flakey_c *fc = ti->private;
	377	struct request_queue *q = bdev_get_queue(fc->dev->bdev);
	378
	379	if (!q->merge_bvec_fn)
	380	return max_size;
	381
	382	bvm->bi_bdev = fc->dev->bdev;
	383	bvm->bi_sector = flakey_map_sector(ti, bvm->bi_sector);
	384
	385	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
	386	}
	387
	388	static int flakey_iterate_devices(struct dm_target ti, iterate_devices_callout_fn fn, void data)
	389	{
	390	struct flakey_c *fc = ti->private;
	391
	392	return fn(ti, fc->dev, fc->start, ti->len, data);
	393	}
	394
	395	static struct target_type flakey_target = {
	396	.name = "flakey",
dfd068b0	397	.version = {1, 2, 0},
3407ef52 JB	398	.module = THIS_MODULE,
	399	.ctr = flakey_ctr,
	400	.dtr = flakey_dtr,
	401	.map = flakey_map,
a3998799	402	.end_io = flakey_end_io,
3407ef52 JB	403	.status = flakey_status,
	404	.ioctl = flakey_ioctl,
	405	.merge = flakey_merge,
	406	.iterate_devices = flakey_iterate_devices,
	407	};
	408
	409	static int __init dm_flakey_init(void)
	410	{
	411	int r = dm_register_target(&flakey_target);
	412
	413	if (r < 0)
	414	DMERR("register failed %d", r);
	415
	416	return r;
	417	}
	418
	419	static void __exit dm_flakey_exit(void)
	420	{
	421	dm_unregister_target(&flakey_target);
	422	}
	423
	424	/* Module hooks */
	425	module_init(dm_flakey_init);
	426	module_exit(dm_flakey_exit);
	427
	428	MODULE_DESCRIPTION(DM_NAME " flakey target");
	429	MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
	430	MODULE_LICENSE("GPL");