Hi David, Any comment on this patchset?
This offline scrub is quite useful and will be core of the incoming xfstests test cases for RAID56 scrub.
Thanks, Qu At 10/28/2016 10:31 AM, Qu Wenruo wrote:
For any one who wants to try it, it can be get from my repo: https://github.com/adam900710/btrfs-progs/tree/fsck_scrub Currently, I only tested it on SINGLE/DUP/RAID1/RAID5 filesystems, with mirror or parity or data corrupted. The tool are all able to detect them and give recoverbility report. Several reports on kernel scrub screwing up good data stripes are in ML for sometime. The reason seems to be lack of csum check before and after reconstruction, and unfinished parity write seems also involved. To get a comparable tool for kernel scrub, we need a user-space tool to act as benchmark to compare their different behaviors. So here is the RFC patch set for user-space scrub. Which can do: 1) All mirror/backup check for non-parity based stripe Which means for RAID1/DUP/RAID10, we can really check all mirrors other than the 1st good mirror. Current "--check-data-csum" option will be finally replace by scrub. As it doesn't really check all mirrors, if it hits a good copy, then resting copies will just be ignored. 2) Comprehensive RAID5/6 full stripe check It will take full use of btrfs csum(both tree and data). It will only recover the full stripe if all recovered data matches with its csum. In fact, it can already expose one new btrfs kernel bug. For example, after screwing up a data stripe, kernel did repairs using parity, but recovered full stripe has wrong parity. Need to scrub again to fix it. And this patchset also introduced new map_block() function, which is more flex than current btrfs_map_block(), and has a unified interface for all profiles. Check the 6th and 7th patch for details. They are already used in RAID5/6 scrub, but can also be used for other profiles too. The to-do list has been shortened, since RAID6 and new check logical is introduced. 1) Repair support In fact, current tool can already report recoverability, repair is not hard to implement. 2) Test cases Need to make the infrastructure able to handle multi-device first. 3) Make btrfsck able to handle RAID5 with missing device Now it doesn't even open RAID5 btrfs with missing device, even though scrub should be able to handle it. Changelog: V0.8 RFC: Initial RFC patchset v1: First formal patchset. RAID6 recovery support added, mainly copied from kernel radi6 lib. Cleaner recovery logical. Qu Wenruo (19): btrfs-progs: raid56: Introduce raid56 header for later recovery usage btrfs-progs: raid56: Introduce tables for RAID6 recovery btrfs-progs: raid56: Allow raid6 to recover 2 data stripes btrfs-progs: raid56: Allow raid6 to recover data and p btrfs-progs: Introduce wrapper to recover raid56 data btrfs-progs: Introduce new btrfs_map_block function which returns more unified result. btrfs-progs: Allow __btrfs_map_block_v2 to remove unrelated stripes btrfs-progs: check/csum: Introduce function to read out one data csum btrfs-progs: check/scrub: Introduce structures to support fsck scrub btrfs-progs: check/scrub: Introduce function to scrub mirror based tree block btrfs-progs: check/scrub: Introduce function to scrub mirror based data blocks btrfs-progs: check/scrub: Introduce function to scrub one extent btrfs-progs: check/scrub: Introduce function to scrub one data stripe btrfs-progs: check/scrub: Introduce function to verify parities btrfs-progs: extent-tree: Introduce function to check if there is any extent in given range. btrfs-progs: check/scrub: Introduce function to recover data parity btrfs-progs: check/scrub: Introduce a function to scrub one full stripe btrfs-progs: check/scrub: Introduce function to check a whole block group btrfs-progs: fsck: Introduce offline scrub function .gitignore | 2 + Documentation/btrfs-check.asciidoc | 8 + Makefile.in | 18 +- check/check.h | 23 + check/csum.c | 96 ++++ check/scrub.c | 924 +++++++++++++++++++++++++++++++++++++ cmds-check.c | 12 +- ctree.h | 2 + disk-io.c | 4 +- disk-io.h | 6 +- extent-tree.c | 52 +++ mktables.c | 142 ++++++ raid56.c | 175 +++++++ raid56.h | 47 ++ volumes.c | 283 ++++++++++++ volumes.h | 49 ++ 16 files changed, 1832 insertions(+), 11 deletions(-) create mode 100644 check/check.h create mode 100644 check/csum.c create mode 100644 check/scrub.c create mode 100644 mktables.c create mode 100644 raid56.h
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