linux-toradex.git/drivers/md/dm-linear.c, branch v3.10.78

dm: rename request variables to bios

2013-03-01T22:45:47+00:00

Use 'bio' in the name of variables and functions that deal with
bios rather than 'request' to avoid confusion with the normal
block layer use of 'request'.

No functional changes.

Signed-off-by: Alasdair G Kergon

dm: fix truncated status strings

2013-03-01T22:45:44+00:00

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.

Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka 
Signed-off-by: Alasdair G Kergon

dm: remove map_info

2012-12-21T20:23:41+00:00

This patch removes map_info from bio-based device mapper targets.
map_info is still used for request-based targets.

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

dm linear: add WRITE SAME support

2012-12-21T20:23:37+00:00

The linear target can already support WRITE SAME requests so signal
this by setting num_write_same_requests to 1.

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

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: 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: 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