Re: [PATCH 3/3] jbd2: check return value of blkdev_issue_flush() for async commits

[Jan Kara]

On Mon 12-10-26 11:47:13, guolingxing wrote:
> When asynchronous commits are enabled, jbd2_commit_transaction()
> calls blkdev_issue_flush() on the journal device to make the commit
> record permanent.  However the return value is ignored so if the
> flush fails, the transaction is considered committed although the
> commit record may have never reached the disk.  Abort the journal
> when the flush fails, as we already do when waiting for the commit
> record fails.
> 
> Fixes: f73bee49855f ("jbd2: Modify ASYNC_COMMIT code to not rely on queue draining on barrier")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: guolingxing <guolingxing@xxxxxxxxxx>
...
> diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
> index 99477e9c78c7..32ca502603be 100644
> --- a/fs/jbd2/commit.c
> +++ b/fs/jbd2/commit.c
> @@ -912,7 +912,10 @@ void jbd2_journal_commit_transaction(journal_t *journal)
>  	stats.run.rs_blocks_logged++;
>  	if (jbd2_has_feature_async_commit(journal) &&
>  	    journal->j_flags & JBD2_BARRIER) {
> -		blkdev_issue_flush(journal->j_dev);
> +		int err = blkdev_issue_flush(journal->j_dev);

Again this shadows existing local variable, which is a bad practice. Just
call this flush_err or something.

> +
> +		if (err)
> +			jbd2_journal_abort(journal, err);

And here we can do instead:
		if (!err)
			err = flush_err;
since below we take care of aborting the journal if err is set.

								Honza

>  	}
>  
>  	if (err)
> -- 
> 2.34.1
> 
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR