dm flakey: add corrupt_bio_byte feature
Add corrupt_bio_byte feature to simulate corruption by overwriting a byte at a specified position with a specified value during intervals when the device is "down". Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Mike Snitzer
Alasdair G Kergon
Родитель
b26f5e3d71
Коммит
a3998799fb
|
|
@ -32,3 +32,22 @@ Optional feature parameters:
|
|||
drop_writes:
|
||||
All write I/O is silently ignored.
|
||||
Read I/O is handled correctly.
|
||||
|
||||
corrupt_bio_byte <Nth_byte> <direction> <value> <flags>:
|
||||
During <down interval>, replace <Nth_byte> of the data of
|
||||
each matching bio with <value>.
|
||||
|
||||
<Nth_byte>: The offset of the byte to replace.
|
||||
Counting starts at 1, to replace the first byte.
|
||||
<direction>: Either 'r' to corrupt reads or 'w' to corrupt writes.
|
||||
'w' is incompatible with drop_writes.
|
||||
<value>: The value (from 0-255) to write.
|
||||
<flags>: Perform the replacement only if bio->bi_rw has all the
|
||||
selected flags set.
|
||||
|
||||
Examples:
|
||||
corrupt_bio_byte 32 r 1 0
|
||||
- replaces the 32nd byte of READ bios with the value 1
|
||||
|
||||
corrupt_bio_byte 224 w 0 32
|
||||
- replaces the 224th byte of REQ_META (=32) bios with the value 0
|
||||
|
|
|
|||
|
|
@ -1,6 +1,6 @@
|
|||
/*
|
||||
* Copyright (C) 2003 Sistina Software (UK) Limited.
|
||||
* Copyright (C) 2004, 2010 Red Hat, Inc. All rights reserved.
|
||||
* Copyright (C) 2004, 2010-2011 Red Hat, Inc. All rights reserved.
|
||||
*
|
||||
* This file is released under the GPL.
|
||||
*/
|
||||
|
|
@ -15,6 +15,9 @@
|
|||
|
||||
#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.
|
||||
|
|
@ -26,6 +29,10 @@ struct flakey_c {
|
|||
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 {
|
||||
|
|
@ -40,7 +47,10 @@ static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
|
|||
const char *arg_name;
|
||||
|
||||
static struct dm_arg _args[] = {
|
||||
{0, 1, "Invalid number of feature 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. */
|
||||
|
|
@ -49,9 +59,9 @@ static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
|
|||
|
||||
r = dm_read_arg_group(_args, as, &argc, &ti->error);
|
||||
if (r)
|
||||
return -EINVAL;
|
||||
return r;
|
||||
|
||||
while (argc && !r) {
|
||||
while (argc) {
|
||||
arg_name = dm_shift_arg(as);
|
||||
argc--;
|
||||
|
||||
|
|
@ -67,11 +77,61 @@ static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
|
|||
continue;
|
||||
}
|
||||
|
||||
ti->error = "Unrecognised flakey feature requested";
|
||||
r = -EINVAL;
|
||||
/*
|
||||
* 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;
|
||||
}
|
||||
|
||||
return r;
|
||||
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;
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -80,6 +140,11 @@ static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
|
|||
*
|
||||
* 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)
|
||||
{
|
||||
|
|
@ -178,31 +243,64 @@ static void flakey_map_bio(struct dm_target *ti, struct bio *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;
|
||||
unsigned rw;
|
||||
|
||||
/* Are we alive ? */
|
||||
elapsed = (jiffies - fc->start_time) / HZ;
|
||||
if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
|
||||
rw = bio_data_dir(bio);
|
||||
/*
|
||||
* Flag this bio as submitted while down.
|
||||
*/
|
||||
map_context->ll = 1;
|
||||
|
||||
/*
|
||||
* Drop writes. Map reads as normal.
|
||||
* Map reads as normal.
|
||||
*/
|
||||
if (bio_data_dir(bio) == READ)
|
||||
goto map_bio;
|
||||
|
||||
/*
|
||||
* Drop writes?
|
||||
*/
|
||||
if (test_bit(DROP_WRITES, &fc->flags)) {
|
||||
if (rw == WRITE) {
|
||||
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;
|
||||
}
|
||||
|
||||
/*
|
||||
* Default setting errors all I/O.
|
||||
* By default, error all I/O.
|
||||
*/
|
||||
return -EIO;
|
||||
}
|
||||
|
|
@ -213,6 +311,24 @@ map_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)
|
||||
{
|
||||
|
|
@ -231,9 +347,17 @@ static int flakey_status(struct dm_target *ti, status_type_t type,
|
|||
fc->down_interval);
|
||||
|
||||
drop_writes = test_bit(DROP_WRITES, &fc->flags);
|
||||
DMEMIT("%u ", drop_writes);
|
||||
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;
|
||||
|
|
@ -275,6 +399,7 @@ static struct target_type flakey_target = {
|
|||
.ctr = flakey_ctr,
|
||||
.dtr = flakey_dtr,
|
||||
.map = flakey_map,
|
||||
.end_io = flakey_end_io,
|
||||
.status = flakey_status,
|
||||
.ioctl = flakey_ioctl,
|
||||
.merge = flakey_merge,
|
||||
|
|
|
|||
Загрузка…
Ссылка в новой задаче