linux-toradex.git/drivers/md/dm-linear.c, branch v3.2.59

dm: fix truncated status strings

2013-03-20T15:03:20+00:00

commit fd7c092e711ebab55b2688d3859d95dfd0301f73 upstream.

Avoid returning a truncated table or status string instead of setting
the DM_BUFFER_FULL_FLAG when the last target of a table fills the
buffer.

When processing a table or status request, the function retrieve_status
calls ti->type->status. If ti->type->status returns non-zero,
retrieve_status assumes that the buffer overflowed and sets
DM_BUFFER_FULL_FLAG.

However, targets don't return non-zero values from their status method
on overflow. Most targets returns always zero.

If a buffer overflow happens in a target that is not the last in the
table, it gets noticed during the next iteration of the loop in
retrieve_status; but if a buffer overflow happens in the last target, it
goes unnoticed and erroneously truncated data is returned.

In the current code, the targets behave in the following way:
* dm-crypt returns -ENOMEM if there is not enough space to store the
  key, but it returns 0 on all other overflows.
* dm-thin returns errors from the status method if a disk error happened.
  This is incorrect because retrieve_status doesn't check the error
  code, it assumes that all non-zero values mean buffer overflow.
* all the other targets always return 0.

This patch changes the ti->type->status function to return void (because
most targets don't use the return code). Overflow is detected in
retrieve_status: if the status method fills up the remaining space
completely, it is assumed that buffer overflow happened.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Alasdair G Kergon 
[bwh: Backported to 3.2:
 - Adjust context
 - dm_status_fn doesn't take a status_flags parameter
 - Bump the last component of each current version (verified not to
   match any version used in mainline)
 - Drop changes to dm-verity]
Signed-off-by: Ben Hutchings

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

2012-01-26T00:13:42+00:00

commit ec8013beddd717d1740cfefb1a9b900deef85462 upstream.

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 
Signed-off-by: Greg Kroah-Hartman

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: linear support discard

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

Allow discards to be passed through to linear mappings if at least one
underlying device supports it.  Discards will be forwarded only to
devices that support them.

A target that supports discards should set num_discard_requests to
indicate how many times each discard request must be submitted to it.

Verify table's underlying devices support discards prior to setting the
associated DM device as capable of discards (via QUEUE_FLAG_DISCARD).

Signed-off-by: Mike Snitzer 
Signed-off-by: Mikulas Patocka 
Reviewed-by: Joe Thornber 
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 table: pass correct dev area size to device_area_is_valid

2009-07-23T19:30:42+00:00

Incorrect device area lengths are being passed to device_area_is_valid().

The regression appeared in 2.6.31-rc1 through commit
754c5fc7ebb417b23601a6222a6005cc2e7f2913.

With the dm-stripe target, the size of the target (ti->len) was used
instead of the stripe_width (ti->len/#stripes).  An example of a
consequent incorrect error message is:

  device-mapper: table: 254:0: sdb too small for target

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

dm target:s introduce iterate devices fn

2009-06-22T09:12:33+00:00

Add .iterate_devices to 'struct target_type' to allow a function to be
called for all devices in a DM target.  Implemented it for all targets
except those in dm-snap.c (origin and snapshot).

(The raid1 version number jumps to 1.12 because we originally reserved
1.1 to 1.11 for 'block_on_error' but ended up using 'handle_errors'
instead.)

Signed-off-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon 
Cc: martin.petersen@oracle.com

dm: linear support flush

2009-06-22T09:12:22+00:00

Flush support for the linear target.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Alasdair G Kergon

dm: remove limited barrier support

2009-04-08T23:27:13+00:00

Prepare for full barrier implementation: first remove the restricted support.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Alasdair G Kergon

dm: support barriers on simple devices

2009-01-06T03:05:09+00:00

Implement barrier support for single device DM devices

This patch implements barrier support in DM for the common case of dm linear
just remapping a single underlying device. In this case we can safely
pass the barrier through because there can be no reordering between
devices.

 NB. Any DM device might cease to support barriers if it gets
     reconfigured so code must continue to allow for a possible
     -EOPNOTSUPP on every barrier bio submitted.  - agk

Signed-off-by: Andi Kleen 
Signed-off-by: Mikulas Patocka 
Signed-off-by: Alasdair G Kergon