2024-05-09 11:52:04

by Zhang Yi

[permalink] [raw]
Subject: Re: [PATCH 7/9] jbd2: remove dead equality check of j_commit_[sequence/request] in kjournald2

On 2024/5/6 22:17, Kemeng Shi wrote:
> In kjournald2, two equality checks of j_commit_[sequence/request] are
> under the same j_state_lock. As j_commit_[sequence/request] are updated
> concurrently with j_state_lock held during runtime, the second check is
> unnecessary.
> The j_commit_sequence is only updated concurrently in
> jbd2_journal_commit_transaction with j_state_lock held.
> The j_commit_request is only updated concurrently in
> __jbd2_log_start_commit with j_state_lock held.
> Also see comment in struct journal_s about lock rule of j_commit_sequence
> and j_commit_request.
>
> Signed-off-by: Kemeng Shi <[email protected]>

Looks reasonable to me.

Reviewed-by: Zhang Yi <[email protected]>

> ---
> fs/jbd2/journal.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index 01e33b643e4d..e8f592fbd6e1 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -224,8 +224,6 @@ static int kjournald2(void *arg)
>
> prepare_to_wait(&journal->j_wait_commit, &wait,
> TASK_INTERRUPTIBLE);
> - if (journal->j_commit_sequence != journal->j_commit_request)
> - should_sleep = 0;
> transaction = journal->j_running_transaction;
> if (transaction && time_after_eq(jiffies,
> transaction->t_expires))
>