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authorJonathan Brassow <jbrassow@redhat.com>2007-07-12 17:29:04 +0100
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-12 15:01:08 -0700
commitf44db678edcc6f4c2779ac43f63f0b9dfa28b724 (patch)
treebbd835d00ca6ed0805c5c7331ebc5dd7978d299c /mm/fremap.c
parentd0d444c7d48c14d59f665887c758fde248f1cb37 (diff)
downloadop-kernel-dev-f44db678edcc6f4c2779ac43f63f0b9dfa28b724.zip
op-kernel-dev-f44db678edcc6f4c2779ac43f63f0b9dfa28b724.tar.gz
dm raid1: handle resync failures
Device-mapper mirroring currently takes a best effort approach to recovery - failures during mirror synchronization are completely ignored. This means that regions are marked 'in-sync' and 'clean' and removed from the hash list. Future reads and writes that query the region will incorrectly interpret the region as in-sync. This patch handles failures during the recovery process. If a failure occurs, the region is marked as 'not-in-sync' (aka RH_NOSYNC) and added to a new list 'failed_recovered_regions'. Regions on the 'failed_recovered_regions' list are not marked as 'clean' upon removal from the list. Furthermore, if the DM_RAID1_HANDLE_ERRORS flag is set, the region is marked as 'not-in-sync'. This action prevents any future read-balancing from choosing an invalid device because of the 'not-in-sync' status. If "handle_errors" is not specified when creating a mirror (leaving the DM_RAID1_HANDLE_ERRORS flag unset), failures will be ignored exactly as they would be without this patch. This is to preserve backwards compatibility with user-space tools, such as 'pvmove'. However, since future read-balancing policies will rely on the correct sync status of a region, a user must choose "handle_errors" when using read-balancing. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/fremap.c')
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