This patchset implement the device scrub/replace function for RAID56, the most implementation of the common data is similar to the other RAID type. The differentia or difficulty is the parity process. The basic idea is reading and check the data which has checksum out of the raid56 stripe lock, if the data is right, then lock the raid56 stripe, read out the other data in the same stripe, if no IO error happens, calculate the parity and check the original one, if the original parity is right, the scrub parity passes. or write out the new one. But if the common data(not parity) that we read out is wrong, we will try to recover it, and then check and repair the parity.
And in order to avoid making the code more and more complex, we copy some code of common data process for the parity, the cleanup work is in my TODO list. We have done some test, the patchset worked well. Of course, more tests are welcome. If you are interesting to use it or test it, you can pull the patchset from https://github.com/miaoxie/linux-btrfs.git raid56-scrub-replace Changelog v2 -> v3: - Fix wrong stripe start logical address calculation which was reported by Chris. - Fix unhandled raid bios for parity scrub, which are added into the plug list of the head raid bio. - Fix possible deadlock caused by the pending bios in the plug list when the io submitters were going to sleep. - Fix undealt use-after-free problem of the source device in the final device replace procedure. - Modify the code that is used to avoid the rbio merge. Changelog v1 -> v2: - Change some function names in raid56.c to make them fit the code style of the raid56. Thanks Miao Miao Xie (8): Btrfs, raid56: don't change bbio and raid_map Btrfs, scrub: repair the common data on RAID5/6 if it is corrupted Btrfs, raid56: use a variant to record the operation type Btrfs, raid56: support parity scrub on raid56 Btrfs, replace: write dirty pages into the replace target device Btrfs, replace: write raid56 parity into the replace target device Btrfs, raid56: fix use-after-free problem in the final device replace procedure on raid56 Btrfs: fix possible deadlock caused by pending I/O in plug list Zhao Lei (3): Btrfs: remove noused bbio_ret in __btrfs_map_block in condition Btrfs: remove unnecessary code of stripe_index assignment in __btrfs_map_block Btrfs, replace: enable dev-replace for raid56 fs/btrfs/dev-replace.c | 20 +- fs/btrfs/raid56.c | 746 ++++++++++++++++++++++++++++++++++++++++----- fs/btrfs/raid56.h | 16 +- fs/btrfs/scrub.c | 803 +++++++++++++++++++++++++++++++++++++++++++++++-- fs/btrfs/volumes.c | 52 +++- fs/btrfs/volumes.h | 14 +- 6 files changed, 1521 insertions(+), 130 deletions(-) -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
