user/sven/linux.git/include/linux/device-mapper.h, branch v3.2.78

dm: fix truncated status strings

2013-03-20T15:03:20Z

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 table: add immutable feature

2011-10-31T20:19:04Z

Introduce DM_TARGET_IMMUTABLE to indicate that the target type cannot be mixed with any other target type, and once loaded into a device, it cannot be replaced with a table containing a different type. The thin provisioning pool device will use this. Signed-off-by: Alasdair G Kergon

dm table: add always writeable feature

2011-10-31T20:19:02Z

Add a target feature flag DM_TARGET_ALWAYS_WRITEABLE to indicate that a target does not support read-only mode. The initial implementation of the thin provisioning target uses this. Signed-off-by: Alasdair G Kergon

dm table: add singleton feature

2011-10-31T20:19:00Z

Introduce the concept of a singleton table which contains exactly one target. If a target type sets the DM_TARGET_SINGLETON feature bit device-mapper will ensure that any table that includes that target contains no others. The thin provisioning pool target uses this. Signed-off-by: Alasdair G Kergon

dm: use local printk ratelimit

2011-10-31T20:18:54Z

printk_ratelimit() shares global ratelimiting state with all other subsystems, so its usage is discouraged. Instead, define and use dm's local state. Signed-off-by: Namhyung Kim Signed-off-by: Alasdair G Kergon

dm crypt: always disable discard_zeroes_data

2011-09-25T22:26:21Z

If optional discard support in dm-crypt is enabled, discards requests bypass the crypt queue and blocks of the underlying device are discarded. For the read path, discarded blocks are handled the same as normal ciphertext blocks, thus decrypted. So if the underlying device announces discarded regions return zeroes, dm-crypt must disable this flag because after decryption there is just random noise instead of zeroes. Signed-off-by: Milan Broz Signed-off-by: Alasdair G Kergon

dm table: share target argument parsing functions

2011-08-02T11:32:04Z

Move multipath target argument parsing code into dm-table so other targets can share it. Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon

dm table: allow targets to support discards internally

2011-05-29T11:52:55Z

Permit a target to support discards regardless of whether or not all its underlying devices do. Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon

md/dm - remove remains of plug_fn callback.

2011-04-18T08:25:41Z

Now that unplugging is done differently, the unplug_fn callback is never called, so it can be completely discarded. Signed-off-by: NeilBrown

block: remove per-queue plugging

2011-03-10T07:52:07Z

Code has been converted over to the new explicit on-stack plugging, and delay users have been converted to use the new API for that. So lets kill off the old plugging along with aops->sync_page(). Signed-off-by: Jens Axboe