linux/Documentation/device-mapper, branch v3.6

Merge branch 'for-next' of git://neil.brown.name/md

2012-08-01T16:02:01Z

Pull md updates from NeilBrown. * 'for-next' of git://neil.brown.name/md: DM RAID: Add support for MD RAID10 md/RAID1: Add missing case for attempting to repair known bad blocks. md/raid5: For odirect-write performance, do not set STRIPE_PREREAD_ACTIVE. md/raid1: don't abort a resync on the first badblock. md: remove duplicated test on ->openers when calling do_md_stop() raid5: Add R5_ReadNoMerge flag which prevent bio from merging at block layer md/raid1: prevent merging too large request md/raid1: read balance chooses idlest disk for SSD md/raid1: make sequential read detection per disk based MD RAID10: Export md_raid10_congested MD: Move macros from raid1*.h to raid1*.c MD RAID1: rename mirror_info structure MD RAID10: rename mirror_info structure MD RAID10: Fix compiler warning. raid5: add a per-stripe lock raid5: remove unnecessary bitmap write optimization raid5: lockless access raid5 overrided bi_phys_segments raid5: reduce chance release_stripe() taking device_lock

DM RAID: Add support for MD RAID10

2012-08-01T10:41:20Z

Support the MD RAID10 personality through dm-raid.c Signed-off-by: Jonathan Brassow Signed-off-by: NeilBrown

dm thin: add read only and fail io modes

2012-07-27T14:08:16Z

Add read-only and fail-io modes to thin provisioning. If a transaction commit fails the pool's metadata device will transition to "read-only" mode. If a commit fails once already in read-only mode the transition to "fail-io" mode occurs. Once in fail-io mode the pool and all associated thin devices will report a status of "Fail". Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon

dm stripe: support for non power of 2 chunksize

2012-07-27T14:08:01Z

Support non-power-of-2 chunk sizes with dm striping for proper alignment of stripe IO on storage that has non-power-of-2 optimal IO sizes (e.g. RAID6 10+2). Signed-off-by: Mike Snitzer Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon

dm stripe: fix size test

2012-07-27T14:08:00Z

dm-stripe is supposed to ensure that all the space allocated to the stripes is fully used and that all stripes are the same size. This patch fixes the test. It checks that device length is divisible by the chunk size and checks that the resulting quotient is divisible by the number of stripes (which is equivalent to testing if device length is divisible by chunk_size * stripes). Previously, the code only tested that the number of sectors in the target was divisible by each of the chunk size and the number of stripes separately, which could leave entire stripes unused. (A setup that genuinely needs some stripes to be shorter than others can be created by concatenating striped targets.) Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon

dm: verity fix documentation

2012-07-03T11:55:41Z

Veritysetup is now part of cryptsetup package. Remove on-disk header description (which is not parsed in kernel) and point users to cryptsetup where it the format is documented. Mention units for block size paramaters. Fix target line specification and dmsetup parameters. Signed-off-by: Milan Broz Cc: stable@kernel.org Signed-off-by: Alasdair G Kergon

dm thin: provide userspace access to pool metadata

2012-06-02T23:30:01Z

This patch implements two new messages that can be sent to the thin pool target allowing it to take a snapshot of the _metadata_. This, read-only snapshot can be accessed by userland, concurrently with the live target. Only one metadata snapshot can be held at a time. The pool's status line will give the block location for the current msnap. Since version 0.1.5 of the userland thin provisioning tools, the thin_dump program displays the msnap as follows: thin_dump -m Available here: https://github.com/jthornber/thin-provisioning-tools Now that userland can access the metadata we can do various things that have traditionally been kernel side tasks: i) Incremental backups. By using metadata snapshots we can work out what blocks have changed over time. Combined with data snapshots we can ensure the data doesn't change while we back it up. A short proof of concept script can be found here: https://github.com/jthornber/thinp-test-suite/blob/master/incremental_backup_example.rb ii) Migration of thin devices from one pool to another. iii) Merging snapshots back into an external origin. iv) Asyncronous replication. Signed-off-by: Joe Thornber Signed-off-by: Alasdair G Kergon

dm: add verity target

2012-03-28T17:43:38Z

This device-mapper target creates a read-only device that transparently validates the data on one underlying device against a pre-generated tree of cryptographic checksums stored on a second device. Two checksum device formats are supported: version 0 which is already shipping in Chromium OS and version 1 which incorporates some improvements. Signed-off-by: Mikulas Patocka Signed-off-by: Mandeep Singh Baines Signed-off-by: Will Drewry Signed-off-by: Elly Jones Cc: Milan Broz Cc: Olof Johansson Cc: Steffen Klassert Cc: Andrew Morton Signed-off-by: Alasdair G Kergon

dm thin: add pool target flags to control discard

2012-03-28T17:41:29Z

Add dm thin target arguments to control discard support. ignore_discard: Disables discard support no_discard_passdown: Don't pass discards down to the underlying data device, but just remove the mapping within the thin provisioning target. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon

dm thin: support read only external snapshot origins

2012-03-28T17:41:28Z

Support the use of an external _read only_ device as an origin for a thin device. Any read to an unprovisioned area of the thin device will be passed through to the origin. Writes trigger allocation of new blocks as usual. One possible use case for this would be VM hosts that want to run guests on thinly-provisioned volumes but have the base image on another device (possibly shared between many VMs). Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon