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Go Back   Linux Archive > Redhat > Device-mapper Development

 
 
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Old 06-27-2011, 07:53 PM
Mike Snitzer
 
Default dm flakey: add ability to specify the corrupting value to be written

Add additional corrupting value argument to corrupt_bio_byte feature.
A value of either 0 or 1 will be written to the specified byte in the
bio. Allowing other arbitrary corrupting values didn't seem necessary.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
drivers/md/dm-flakey.c | 27 +++++++++++++++++++--------
1 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index 0205b00..58cebca 100644
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -29,6 +29,7 @@ struct flakey_c {
unsigned long flags;
unsigned corrupt_bio_byte;
unsigned corrupt_bio_flags;
+ unsigned corrupt_bio_value;
};

enum feature_flag_bits {
@@ -43,9 +44,10 @@ static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
const char *arg_name;

static struct dm_arg _args[] = {
- {0, 4, "invalid number of feature args"},
+ {0, 5, "invalid number of feature args"},
{1, UINT_MAX, "invalid corrupt bio byte value"},
{0, UINT_MAX, "invalid corrupt bio flags mask"},
+ {0, 1, "invalid value to corrupt bio"},
};

r = dm_read_arg(_args, dm_shift_arg(as), &argc, &ti->error);
@@ -59,7 +61,7 @@ static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
arg_name = dm_shift_arg(as);
argc--;

- /* corrupt_bio_byte <Nth byte> <bio_flags> */
+ /* corrupt_bio_byte <Nth byte> <bio_flags> <value> */
if (!strnicmp(arg_name, MESG_STR("corrupt_bio_byte")) &&
(argc >= 1)) {
r = dm_read_arg(_args + 1, dm_shift_arg(as),
@@ -73,6 +75,11 @@ static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
r = dm_read_arg(_args + 2, dm_shift_arg(as),
&fc->corrupt_bio_flags, &ti->error);
argc--;
+
+ /* allow user to write a 0 or 1 to the specified byte */
+ r = dm_read_arg(_args + 3, dm_shift_arg(as),
+ &fc->corrupt_bio_value, &ti->error);
+ argc--;
continue;
}

@@ -202,10 +209,14 @@ static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc)
unsigned bio_bytes = bio_cur_bytes(bio);
char *data = bio_data(bio);

- /* write 0 to the specified Nth byte of the bio */
+ /* write to the specified Nth byte of the bio */
if (data && bio_bytes >= fc->corrupt_bio_byte) {
- data[fc->corrupt_bio_byte-1] = 0;
- printk("corrupting data rw=%lu
", bio_data_dir(bio));
+ data[fc->corrupt_bio_byte-1] = fc->corrupt_bio_value;
+
+ printk("corrupting data bio=%p by writing %u to byte %u "
+ "(rw=%lu flags=%lu bi_sector=%lu cur_bytes=%u)
",
+ bio, fc->corrupt_bio_value, fc->corrupt_bio_byte,
+ bio_data_dir(bio), bio->bi_rw, bio->bi_sector, bio_bytes);
}
}

@@ -281,11 +292,11 @@ static int flakey_status(struct dm_target *ti, status_type_t type,

drop_writes = test_bit(DROP_WRITES, &fc->flags);
DMEMIT("%u ", drop_writes +
- (fc->corrupt_bio_byte > 0) * 3);
+ (fc->corrupt_bio_byte > 0) * 4);

if (fc->corrupt_bio_byte)
- DMEMIT("corrupt_bio_byte %u %u ", fc->corrupt_bio_byte,
- fc->corrupt_bio_flags);
+ DMEMIT("corrupt_bio_byte %u %u %u ", fc->corrupt_bio_byte,
+ fc->corrupt_bio_flags, fc->corrupt_bio_value);
if (drop_writes)
DMEMIT("drop_writes ");
break;
--
1.7.1

--
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