Re: [PATCH 4/5] jbd: fix error handling for checkpoint io

Jan Kara
2008-06-03T08:02:53Z

On Tue 03-06-08 13:40:25, Hidehiro Kawai wrote:
> Subject: [PATCH 4/5] jbd: fix error handling for checkpoint io
>
> When a checkpointing IO fails, current JBD code doesn't check the
> error and continue journaling. This means latest metadata can be
> lost from both the journal and filesystem.
>
> This patch leaves the failed metadata blocks in the journal space
> and aborts journaling in the case of log_do_checkpoint().
> To achieve this, we need to do:
>
> 1. don't remove the failed buffer from the checkpoint list where in
> the case of __try_to_free_cp_buf() because it may be released or
> overwritten by a later transaction
> 2. log_do_checkpoint() is the last chance, remove the failed buffer
> from the checkpoint list and abort the journal
> 3. when checkpointing fails, don't update the journal super block to
> prevent the journaled contents from being cleaned. For safety,
> don't update j_tail and j_tail_sequence either
> 4. when checkpointing fails, notify this error to the ext3 layer so
> that ext3 don't clear the needs_recovery flag, otherwise the
> journaled contents are ignored and cleaned in the recovery phase
> 5. if the recovery fails, keep the needs_recovery flag
> 6. prevent cleanup_journal_tail() from being called between
> __journal_drop_transaction() and journal_abort() (a race issue
> between journal_flush() and __log_wait_for_space()
>
> Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
You can add:
Acked-by: Jan Kara <jack@suse.cz>

Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR