linux.git/drivers/md/dm-crypt.c, branch v2.6.37

dm: implement REQ_FLUSH/FUA support for bio-based dm

2010-09-10T10:35:38+00:00

This patch converts bio-based dm to support REQ_FLUSH/FUA instead of
now deprecated REQ_HARDBARRIER.

* -EOPNOTSUPP handling logic dropped.

* Preflush is handled as before but postflush is dropped and replaced
  with passing down REQ_FUA to member request_queues.  This replaces
  one array wide cache flush w/ member specific FUA writes.

* __split_and_process_bio() now calls __clone_and_map_flush() directly
  for flushes and guarantees all FLUSH bio's going to targets are zero
`  length.

* It's now guaranteed that all FLUSH bio's which are passed onto dm
  targets are zero length.  bio_empty_barrier() tests are replaced
  with REQ_FLUSH tests.

* Empty WRITE_BARRIERs are replaced with WRITE_FLUSHes.

* Dropped unlikely() around REQ_FLUSH tests.  Flushes are not unlikely
  enough to be marked with unlikely().

* Block layer now filters out REQ_FLUSH/FUA bio's if the request_queue
  doesn't support cache flushing.  Advertise REQ_FLUSH | REQ_FUA
  capability.

* Request based dm isn't converted yet.  dm_init_request_based_queue()
  resets flush support to 0 for now.  To avoid disturbing request
  based dm code, dm->flush_error is added for bio based dm while
  requested based dm continues to use dm->barrier_error.

Lightly tested linear, stripe, raid1, snap and crypt targets.  Please
proceed with caution as I'm not familiar with the code base.

Signed-off-by: Tejun Heo 
Cc: dm-devel@redhat.com
Cc: Christoph Hellwig 
Signed-off-by: Jens Axboe

dm: use dm_target_offset macro

2010-08-12T03:14:11+00:00

Use new dm_target_offset() macro to avoid most references to ti->begin
in dm targets.

Signed-off-by: Alasdair G Kergon

dm crypt: simplify crypt_ctr

2010-08-12T03:14:07+00:00

Allocate cipher strings indpendently of struct crypt_config and move
cipher parsing and allocation into a separate function to prepare for
supporting the cryptoapi format e.g. "xts(aes)".

No functional change in this patch.

Signed-off-by: Milan Broz 
Signed-off-by: Alasdair G Kergon

dm crypt: simplify crypt_config destruction logic

2010-08-12T03:14:06+00:00

Use just one label and reuse common destructor for crypt target.

Parse remaining argv arguments in logic order.

Also do not ignore error values from IV init and set key functions.

No functional change in this patch except changed return codes
based on above.

Signed-off-by: Milan Broz 
Signed-off-by: Alasdair G Kergon

dm crypt: use kstrdup

2010-08-12T03:13:58+00:00

Use kstrdup when the goal of an allocation is copy a string into the
allocated region.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// 
@@
expression from,to;
expression flag,E1,E2;
statement S;
@@

-  to = kmalloc(strlen(from) + 1,flag);
+  to = kstrdup(from, flag);
   ... when != \(from = E1 \| to = E1 \)
   if (to==NULL || ...) S
   ... when != \(from = E2 \| to = E2 \)
-  strcpy(to, from);
// 

Signed-off-by: Julia Lawall 
Signed-off-by: Alasdair G Kergon

dm table: remove unused dm_get_device range parameters

2010-03-06T02:32:27+00:00

Remove unused parameters(start and len) of dm_get_device()
and fix the callers.

Signed-off-by: Nikanth Karthikesan 
Signed-off-by: Alasdair G Kergon

dm crypt: add plain64 iv

2009-12-10T23:52:25+00:00

The default plain IV is 32-bit only.

This plain64 IV provides a compatible mode for encrypted devices bigger
than 4TB.

Signed-off-by: Milan Broz 
Signed-off-by: Alasdair G Kergon

dm crypt: make wipe message also wipe essiv key

2009-12-10T23:51:57+00:00

The "wipe key" message is used to wipe the volume key from memory
temporarily, for example when suspending to RAM.

But the initialisation vector in ESSIV mode is calculated from the
hashed volume key, so the wipe message should wipe this IV key too and
reinitialise it when the volume key is reinstated.

This patch adds an IV wipe method called from a wipe message callback.
ESSIV is then reinitialised using the init function added by the
last patch.

Cc: stable@kernel.org
Signed-off-by: Milan Broz 
Signed-off-by: Alasdair G Kergon

dm crypt: separate essiv allocation from initialisation

2009-12-10T23:51:56+00:00

This patch separates the construction of IV from its initialisation.
(For ESSIV it is a hash calculation based on volume key.)

Constructor code now preallocates hash tfm and salt array
and saves it in a private IV structure.

The next patch requires this to reinitialise the wiped IV
without reallocating memory when resuming a suspended device.

Cc: stable@kernel.org
Signed-off-by: Milan Broz 
Signed-off-by: Alasdair G Kergon

dm crypt: restructure essiv error path

2009-12-10T23:51:56+00:00

Use kzfree for salt deallocation because it is derived from the volume
key.  Use a common error path in ESSIV constructor.

Required by a later patch which fixes the way key material is wiped
from memory.

Cc: stable@kernel.org
Signed-off-by: Milan Broz 
Signed-off-by: Alasdair G Kergon