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

	devname = dm_shift_arg(&as);

	if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 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 (fc->corrupt_bio_byte && !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;
	struct dm_dev *dev = fc->dev;
	int r = 0;

	/*
	 * Only pass ioctls through if the device sizes match exactly.
	 */
	if (fc->start ||
	    ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
		r = scsi_verify_blk_ioctl(NULL, cmd);

	return r ? : __blkdev_driver_ioctl(dev->bdev, 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 <[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 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;
31998ef1	163	char dummy;
3407ef52	164
dfd068b0 MS	165	as.argc = argc;
	166	as.argv = argv;
	167
	168	if (argc < 4) {
	169	ti->error = "Invalid argument count";
3407ef52 JB	170	return -EINVAL;
	171	}
	172
b26f5e3d	173	fc = kzalloc(sizeof(*fc), GFP_KERNEL);
3407ef52	174	if (!fc) {
dfd068b0	175	ti->error = "Cannot allocate linear context";
3407ef52 JB	176	return -ENOMEM;
	177	}
	178	fc->start_time = jiffies;
	179
dfd068b0 MS	180	devname = dm_shift_arg(&as);
dfd068b0 MS	181
31998ef1	182	if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1) {
dfd068b0	183	ti->error = "Invalid device sector";
3407ef52 JB	184	goto bad;
3407ef52 JB	185	}
dfd068b0	186	fc->start = tmpll;
3407ef52	187
dfd068b0 MS	188	r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
dfd068b0 MS	189	if (r)
3407ef52	190	goto bad;
3407ef52	191
dfd068b0 MS	192	r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
dfd068b0 MS	193	if (r)
3407ef52	194	goto bad;
3407ef52 JB	195
3407ef52 JB	196	if (!(fc->up_interval + fc->down_interval)) {
dfd068b0	197	ti->error = "Total (up + down) interval is zero";
3407ef52 JB	198	goto bad;
	199	}
	200
	201	if (fc->up_interval + fc->down_interval < fc->up_interval) {
dfd068b0	202	ti->error = "Interval overflow";
3407ef52 JB	203	goto bad;
	204	}
	205
b26f5e3d	206	r = parse_features(&as, fc, ti);
dfd068b0 MS	207	if (r)
	208	goto bad;
	209
	210	if (dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev)) {
	211	ti->error = "Device lookup failed";
3407ef52 JB	212	goto bad;
	213	}
	214
	215	ti->num_flush_requests = 1;
30e4171b	216	ti->num_discard_requests = 1;
3407ef52 JB	217	ti->private = fc;
	218	return 0;
	219
	220	bad:
	221	kfree(fc);
	222	return -EINVAL;
	223	}
	224
	225	static void flakey_dtr(struct dm_target *ti)
	226	{
	227	struct flakey_c *fc = ti->private;
	228
	229	dm_put_device(ti, fc->dev);
	230	kfree(fc);
	231	}
	232
	233	static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector)
	234	{
	235	struct flakey_c *fc = ti->private;
	236
30e4171b	237	return fc->start + dm_target_offset(ti, bi_sector);
3407ef52 JB	238	}
	239
	240	static void flakey_map_bio(struct dm_target ti, struct bio bio)
	241	{
	242	struct flakey_c *fc = ti->private;
	243
	244	bio->bi_bdev = fc->dev->bdev;
	245	if (bio_sectors(bio))
	246	bio->bi_sector = flakey_map_sector(ti, bio->bi_sector);
	247	}
	248
a3998799 MS	249	static void corrupt_bio_data(struct bio bio, struct flakey_c fc)
	250	{
	251	unsigned bio_bytes = bio_cur_bytes(bio);
	252	char *data = bio_data(bio);
	253
	254	/*
	255	* Overwrite the Nth byte of the data returned.
	256	*/
	257	if (data && bio_bytes >= fc->corrupt_bio_byte) {
	258	data[fc->corrupt_bio_byte - 1] = fc->corrupt_bio_value;
	259
	260	DMDEBUG("Corrupting data bio=%p by writing %u to byte %u "
	261	"(rw=%c bi_rw=%lu bi_sector=%llu cur_bytes=%u)\n",
	262	bio, fc->corrupt_bio_value, fc->corrupt_bio_byte,
	263	(bio_data_dir(bio) == WRITE) ? 'w' : 'r',
	264	bio->bi_rw, (unsigned long long)bio->bi_sector, bio_bytes);
	265	}
	266	}
	267
3407ef52 JB	268	static int flakey_map(struct dm_target ti, struct bio bio,
	269	union map_info *map_context)
	270	{
	271	struct flakey_c *fc = ti->private;
	272	unsigned elapsed;
	273
	274	/* Are we alive ? */
	275	elapsed = (jiffies - fc->start_time) / HZ;
b26f5e3d	276	if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
a3998799 MS	277	/*
	278	* Flag this bio as submitted while down.
	279	*/
	280	map_context->ll = 1;
	281
	282	/*
	283	* Map reads as normal.
	284	*/
	285	if (bio_data_dir(bio) == READ)
	286	goto map_bio;
b26f5e3d MS	287
b26f5e3d MS	288	/*
a3998799	289	* Drop writes?
b26f5e3d MS	290	*/
b26f5e3d MS	291	if (test_bit(DROP_WRITES, &fc->flags)) {
a3998799 MS	292	bio_endio(bio, 0);
	293	return DM_MAPIO_SUBMITTED;
	294	}
	295
	296	/*
	297	* Corrupt matching writes.
	298	*/
	299	if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == WRITE)) {
	300	if (all_corrupt_bio_flags_match(bio, fc))
	301	corrupt_bio_data(bio, fc);
b26f5e3d MS	302	goto map_bio;
	303	}
	304
	305	/*
a3998799	306	* By default, error all I/O.
b26f5e3d	307	*/
3407ef52	308	return -EIO;
b26f5e3d	309	}
3407ef52	310
b26f5e3d	311	map_bio:
3407ef52 JB	312	flakey_map_bio(ti, bio);
	313
	314	return DM_MAPIO_REMAPPED;
	315	}
	316
a3998799 MS	317	static int flakey_end_io(struct dm_target ti, struct bio bio,
	318	int error, union map_info *map_context)
	319	{
	320	struct flakey_c *fc = ti->private;
	321	unsigned bio_submitted_while_down = map_context->ll;
	322
	323	/*
	324	* Corrupt successful READs while in down state.
	325	* If flags were specified, only corrupt those that match.
	326	*/
1212268f	327	if (fc->corrupt_bio_byte && !error && bio_submitted_while_down &&
a3998799 MS	328	(bio_data_dir(bio) == READ) && (fc->corrupt_bio_rw == READ) &&
	329	all_corrupt_bio_flags_match(bio, fc))
	330	corrupt_bio_data(bio, fc);
	331
	332	return error;
	333	}
	334
3407ef52 JB	335	static int flakey_status(struct dm_target *ti, status_type_t type,
	336	char *result, unsigned int maxlen)
	337	{
b26f5e3d	338	unsigned sz = 0;
3407ef52	339	struct flakey_c *fc = ti->private;
b26f5e3d	340	unsigned drop_writes;
3407ef52 JB	341
	342	switch (type) {
	343	case STATUSTYPE_INFO:
	344	result[0] = '\0';
	345	break;
	346
	347	case STATUSTYPE_TABLE:
b26f5e3d MS	348	DMEMIT("%s %llu %u %u ", fc->dev->name,
	349	(unsigned long long)fc->start, fc->up_interval,
	350	fc->down_interval);
	351
	352	drop_writes = test_bit(DROP_WRITES, &fc->flags);
a3998799 MS	353	DMEMIT("%u ", drop_writes + (fc->corrupt_bio_byte > 0) * 5);
a3998799 MS	354
b26f5e3d MS	355	if (drop_writes)
b26f5e3d MS	356	DMEMIT("drop_writes ");
a3998799 MS	357
	358	if (fc->corrupt_bio_byte)
	359	DMEMIT("corrupt_bio_byte %u %c %u %u ",
	360	fc->corrupt_bio_byte,
	361	(fc->corrupt_bio_rw == WRITE) ? 'w' : 'r',
	362	fc->corrupt_bio_value, fc->corrupt_bio_flags);
	363
3407ef52 JB	364	break;
	365	}
	366	return 0;
	367	}
	368
	369	static int flakey_ioctl(struct dm_target *ti, unsigned int cmd, unsigned long arg)
	370	{
	371	struct flakey_c *fc = ti->private;
ec8013be PB	372	struct dm_dev *dev = fc->dev;
ec8013be PB	373	int r = 0;
3407ef52	374
ec8013be PB	375	/*
	376	* Only pass ioctls through if the device sizes match exactly.
	377	*/
	378	if (fc->start \|\|
	379	ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
	380	r = scsi_verify_blk_ioctl(NULL, cmd);
	381
	382	return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg);
3407ef52 JB	383	}
	384
	385	static int flakey_merge(struct dm_target ti, struct bvec_merge_data bvm,
	386	struct bio_vec *biovec, int max_size)
	387	{
	388	struct flakey_c *fc = ti->private;
	389	struct request_queue *q = bdev_get_queue(fc->dev->bdev);
	390
	391	if (!q->merge_bvec_fn)
	392	return max_size;
	393
	394	bvm->bi_bdev = fc->dev->bdev;
	395	bvm->bi_sector = flakey_map_sector(ti, bvm->bi_sector);
	396
	397	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
	398	}
	399
	400	static int flakey_iterate_devices(struct dm_target ti, iterate_devices_callout_fn fn, void data)
	401	{
	402	struct flakey_c *fc = ti->private;
	403
	404	return fn(ti, fc->dev, fc->start, ti->len, data);
	405	}
	406
	407	static struct target_type flakey_target = {
	408	.name = "flakey",
dfd068b0	409	.version = {1, 2, 0},
3407ef52 JB	410	.module = THIS_MODULE,
	411	.ctr = flakey_ctr,
	412	.dtr = flakey_dtr,
	413	.map = flakey_map,
a3998799	414	.end_io = flakey_end_io,
3407ef52 JB	415	.status = flakey_status,
	416	.ioctl = flakey_ioctl,
	417	.merge = flakey_merge,
	418	.iterate_devices = flakey_iterate_devices,
	419	};
	420
	421	static int __init dm_flakey_init(void)
	422	{
	423	int r = dm_register_target(&flakey_target);
	424
	425	if (r < 0)
	426	DMERR("register failed %d", r);
	427
	428	return r;
	429	}
	430
	431	static void __exit dm_flakey_exit(void)
	432	{
	433	dm_unregister_target(&flakey_target);
	434	}
	435
	436	/* Module hooks */
	437	module_init(dm_flakey_init);
	438	module_exit(dm_flakey_exit);
	439
	440	MODULE_DESCRIPTION(DM_NAME " flakey target");
	441	MODULE_AUTHOR("Joe Thornber <[email protected]>");
	442	MODULE_LICENSE("GPL");