linux-toradex.git/drivers/md/dm-flakey.c, branch v3.6-rc2

dm thin: commit before gathering status

2012-07-27T14:08:16+00:00

Commit outstanding metadata before returning the status for a dm thin
pool so that the numbers reported are as up-to-date as possible.

The commit is not performed if the device is suspended or if
the DM_NOFLUSH_FLAG is supplied by userspace and passed to the target
through a new 'status_flags' parameter in the target's dm_status_fn.

The userspace dmsetup tool will support the --noflush flag with the
'dmsetup status' and 'dmsetup wait' commands from version 1.02.76
onwards.

Tested-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon

dm: reject trailing characters in sccanf input

2012-03-28T17:41:26+00:00

Device mapper uses sscanf to convert arguments to numbers. The problem is that
the way we use it ignores additional unmatched characters in the scanned string.

For example, this `if (sscanf(string, "%d", &number) == 1)' will match a number,
but also it will match number with some garbage appended, like "123abc".

As a result, device mapper accepts garbage after some numbers. For example
the command `dmsetup create vg1-new --table "0 16384 linear 254:1bla 34816bla"'
will pass without an error.

This patch fixes all sscanf uses in device mapper. It appends "%c" with
a pointer to a dummy character variable to every sscanf statement.

The construct `if (sscanf(string, "%d%c", &number, &dummy) == 1)' succeeds
only if string is a null-terminated number (optionally preceded by some
whitespace characters). If there is some character appended after the number,
sscanf matches "%c", writes the character to the dummy variable and returns 2.
We check the return value for 1 and consequently reject numbers with some
garbage appended.

Signed-off-by: Mikulas Patocka 
Acked-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon

dm flakey: fix crash on read when corrupt_bio_byte not set

2012-03-07T19:09:39+00:00

The following BUG is hit on the first read that is submitted to a dm
flakey test device while the device is "down" if the corrupt_bio_byte
feature wasn't requested when the device's table was loaded.

Example DM table that will hit this BUG:
0 2097152 flakey 8:0 2048 0 30

This bug was introduced by commit a3998799fb4df0b0af8271a7d50c4269032397aa
(dm flakey: add corrupt_bio_byte feature) in v3.1-rc1.

BUG: unable to handle kernel paging request at ffff8801cfce3fff
IP: [] corrupt_bio_data+0x6e/0xae [dm_flakey]
PGD 1606063 PUD 0
Oops: 0002 [#1] SMP
...
Call Trace:
 
 [] flakey_end_io+0x42/0x48 [dm_flakey]
 [] clone_endio+0x54/0xb6 [dm_mod]
 [] bio_endio+0x2d/0x2f
 [] req_bio_endio+0x96/0x9f
 [] blk_update_request+0x1dc/0x3a9
 [] ? rcu_read_unlock+0x21/0x23
 [] blk_update_bidi_request+0x20/0x6e
 [] blk_end_bidi_request+0x1f/0x5d
 [] blk_end_request+0x10/0x12
 [] scsi_io_completion+0x1e5/0x4b1
 [] scsi_finish_command+0xec/0xf5
 [] scsi_softirq_done+0xff/0x108
 [] blk_done_softirq+0x84/0x98
 [] __do_softirq+0xe3/0x1d5
 [] ? _raw_spin_lock+0x62/0x69
 [] ? handle_irq_event+0x4c/0x61
 [] call_softirq+0x1c/0x30
 [] do_softirq+0x4b/0xa3
 [] irq_exit+0x53/0xca
 [] do_IRQ+0x9d/0xb4
 [] common_interrupt+0x73/0x73
...

Signed-off-by: Mike Snitzer 
Cc: stable@vger.kernel.org # 3.1+
Signed-off-by: Alasdair G Kergon

dm: do not forward ioctls from logical volumes to the underlying device

2012-01-14T23:07:24+00:00

A logical volume can map to just part of underlying physical volume.
In this case, it must be treated like a partition.

Based on a patch from Alasdair G Kergon.

Cc: Alasdair G Kergon 
Cc: dm-devel@redhat.com
Signed-off-by: Paolo Bonzini 
Signed-off-by: Linus Torvalds

dm: flakey fix corrupt_bio_byte error path

2011-09-25T22:26:15+00:00

If no arguments were provided to the corrupt_bio_byte feature an error
should be returned immediately.

Reported-by: Zdenek Kabelac 
Signed-off-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon

dm flakey: add corrupt_bio_byte feature

2011-08-02T11:32:06+00:00

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 
Signed-off-by: Alasdair G Kergon

dm flakey: add drop_writes

2011-08-02T11:32:05+00:00

Add 'drop_writes' option to drop writes silently while the
device is 'down'.  Reads are not touched.

Signed-off-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon

dm flakey: support feature args

2011-08-02T11:32:05+00:00

Add the ability to specify arbitrary feature flags when creating a
flakey target.  This code uses the same target argument helpers that
the multipath target does.

Also remove the superfluous 'dm-flakey' prefixes from the error messages,
as they already contain the prefix 'flakey'.

Signed-off-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon

dm flakey: use dm_target_offset and support discards

2011-08-02T11:32:05+00:00

Use dm_target_offset() and support discards.

Signed-off-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon

dm: add flakey target

2011-03-24T13:54:24+00:00

This target is the same as the linear target except that it returns I/O
errors periodically.  It's been found useful in simulating failing
devices for testing purposes.

I needed a dm target to do some failure testing on btrfs's raid code, and
Mike pointed me at this.

Signed-off-by: Josef Bacik 
Signed-off-by: Alasdair G Kergon