Hello Kudu Jenkins,
I'd like you to reexamine a change. Please visit
http://gerrit.cloudera.org:8080/6715
to look at the new patch set (#4).
Change subject: KUDU-1978: avoid corruption when deleting misaligned blocks
......................................................................
KUDU-1978: avoid corruption when deleting misaligned blocks
The gist of the problem: when punching out blocks, we don't actually know
where they end. The existing code assumes that proper alignment is always
maintained, but when faced with a repeated sequence of blocks misaligned on
both start and end offsets, this may not be true. It is conceivable (though
not certain) that KUDU-1793 can cause such sequences.
To fix, we could maintain per-block end offsets, but that'd be expensive for
such a rare case (remember: we have millions of blocks). Instead, we'll look
for blocks misaligned on their start offsets and skip the align up step when
punching them out. This means we won't reclaim all of their space, but it's
better than corrupting data belonging to the next block.
A black box reproduction of KUDU-1793 is virtually impossible, so here's a
white box implementation instead, via augmentation of the LBMCorruptor's
misaligned block generator. Without the fix (though with the removal of the
DCHECK_EQ), the new test fails 100% of the time. With the fix, it hasn't
failed in 1000 runs.
Change-Id: I6ed6e349ab10d8d04722cd7ef99e7a06554f51f1
---
M src/kudu/fs/log_block_manager-test-util.cc
M src/kudu/fs/log_block_manager-test-util.h
M src/kudu/fs/log_block_manager-test.cc
M src/kudu/fs/log_block_manager.cc
4 files changed, 180 insertions(+), 42 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/kudu refs/changes/15/6715/4
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I6ed6e349ab10d8d04722cd7ef99e7a06554f51f1
Gerrit-PatchSet: 4
Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-Owner: Adar Dembo <a...@cloudera.com>
Gerrit-Reviewer: Adar Dembo <a...@cloudera.com>
Gerrit-Reviewer: David Ribeiro Alves <davidral...@gmail.com>
Gerrit-Reviewer: Kudu Jenkins
Gerrit-Reviewer: Todd Lipcon <t...@apache.org>
