linux/Documentation/device-mapper, branch v3.9

Merge tag 'md-3.9' of git://neil.brown.name/md

2013-03-06T01:22:08Z

Pull md updates from NeilBrown: "Mostly little bugfixes. Only "feature" is a new RAID10 layout which slightly improves the number of sets of devices that can concurrently fail, without data loss." * tag 'md-3.9' of git://neil.brown.name/md: md: expedite metadata update when switching read-auto -> active md: remove CONFIG_MULTICORE_RAID456 md/raid1,raid10: fix deadlock with freeze_array() md/raid0: improve error message when converting RAID4-with-spares to RAID0 md: raid0: fix error return from create_stripe_zones. md: fix two bugs when attempting to resize RAID0 array. DM RAID: Add support for MD's RAID10 "far" and "offset" algorithms MD RAID10: Improve redundancy for 'far' and 'offset' algorithms (part 2) MD RAID10: Improve redundancy for 'far' and 'offset' algorithms (part 1) MD RAID10: Minor non-functional code changes md: raid1,10: Handle REQ_WRITE_SAME flag in write bios md: protect against crash upon fsync on ro array

dm cache: add cleaner policy

2013-03-01T22:45:52Z

A simple cache policy that writes back all data to the origin. This is used to decommission a dm cache by emptying it. Signed-off-by: Heinz Mauelshagen Signed-off-by: Joe Thornber Signed-off-by: Alasdair G Kergon

dm cache: add mq policy

2013-03-01T22:45:51Z

A cache policy that uses a multiqueue ordered by recent hit count to select which blocks should be promoted and demoted. This is meant to be a general purpose policy. It prioritises reads over writes. Signed-off-by: Joe Thornber Signed-off-by: Alasdair G Kergon

dm: add cache target

2013-03-01T22:45:51Z

Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber Signed-off-by: Heinz Mauelshagen Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon

DM RAID: Add support for MD's RAID10 "far" and "offset" algorithms

2013-02-26T00:55:36Z

DM RAID: Add support for MD's RAID10 "far" and "offset" algorithms Until now, dm-raid.c only supported the "near" algorthm of MD's RAID10 implementation. This patch adds support for the "far" and "offset" algorithms, but only with the improved redundancy that is brought with the introduction of the 'use_far_sets' bit, which shifts copied stripes according to smaller sets vs the entire array. That is, the 17th bit of the 'layout' variable that defines the RAID10 implementation will always be set. (More information on how the 'layout' variable selects the RAID10 algorithm can be found in the opening comments of drivers/md/raid10.c.) Signed-off-by: Jonathan Brassow Signed-off-by: NeilBrown

DM-RAID: Fix RAID10's check for sufficient redundancy

2013-01-24T01:02:36Z

Before attempting to activate a RAID array, it is checked for sufficient redundancy. That is, we make sure that there are not too many failed devices - or devices specified for rebuild - to undermine our ability to activate the array. The current code performs this check twice - once to ensure there were not too many devices specified for rebuild by the user ('validate_rebuild_devices') and again after possibly experiencing a failure to read the superblock ('analyse_superblocks'). Neither of these checks are sufficient. The first check is done properly but with insufficient information about the possible failure state of the devices to make a good determination if the array can be activated. The second check is simply done wrong in the case of RAID10 because it doesn't account for the independence of the stripes (i.e. mirror sets). The solution is to use the properly written check ('validate_rebuild_devices'), but perform the check after the superblocks have been read and we know which devices have failed. This gives us one check instead of two and performs it in a location where it can be done right. Only RAID10 was affected and it was affected in the following ways: - the code did not properly catch the condition where a user specified a device for rebuild that already had a failed device in the same mirror set. (This condition would, however, be caught at a deeper level in MD.) - the code triggers a false positive and denies activation when devices in independent mirror sets have failed - counting the failures as though they were all in the same set. The most likely place this error was introduced (or this patch should have been included) is in commit 4ec1e369 - first introduced in v3.7-rc1. Consequently this fix should also go in v3.7.y, however there is a small conflict on the .version in raid_target, so I'll submit a separate patch to -stable. Cc: stable@vger.kernel.org Signed-off-by: Jonathan Brassow Signed-off-by: NeilBrown

DM RAID: Add rebuild capability for RAID10

2012-10-11T02:40:24Z

DM RAID: Add code to validate replacement slots for RAID10 arrays RAID10 can handle 'copies - 1' failures for each mirror group. This code ensures the user has provided a valid array - one whose devices specified for rebuild do not exceed the amount of redundancy available. Signed-off-by: Jonathan Brassow Signed-off-by: NeilBrown

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