If I am thinking correctly, journal would be checkpointed on filesystem
unmount calls.
This implies the given scenario would be pretty rare.
ie first filesystem should be mounted in full-journal mode, and crashed
prior to checkpoint.
then it should be remounted in no-journalled-data mode without recovery
and again remounted in full journalled mode with recovery.
Am I thinking on correct lines?
On Tuesday 26 April 2011 02:53 PM, Ding Dinghua wrote:
I think it's not only a performance issue but more important, a
correctness issue.
Revoke table is used for preventing the wrong replay of journal which
cause data corruption:
If block A has been journalled its modification, committed to journal
and hasn't been checkpointed,
and in later transactions block A is freed and reused for data in
no-journalled-data mode, then If
we don't have revoke table which recording the releasing event, replay
of journal will overwrite the new data,
which causing data corruption.
2011/4/26 Yongqiang Yang<xiaoqiangnk@xxxxxxxxx>:
AFAIK, it can accelerate the recovering process. If a block is in the
revoke table of a transaction t1 and t1 is committed, then the there
is no need to recover the block in transactions which is earlier than
t1.
On Tue, Apr 26, 2011 at 4:29 PM, Niraj Kulkarni
<kulkarniniraj14@xxxxxxxxx> wrote:
Hi all,
I am new to fs development. I am trying to modify the journal structure
of JBD. While analyzing the code, I could understand most of the things, but
I am not able to understand the need of revoke mechanism. Can anybody
enlighten me on this issue?
Regards
Niraj
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Best Wishes
Yongqiang Yang
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