Date:   Thu, 13 Jan 2022 12:30:51 +0100
From:   Jan Kara <jack@suse.cz>
To:     Ritesh Harjani <riteshh@linux.ibm.com>
Cc:     linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, Jan Kara <jack@suse.com>,
        Andreas Dilger <adilger.kernel@dilger.ca>, tytso@mit.edu,
        Eric Whitney <enwlinux@gmail.com>
Subject: Re: [PATCH 5/6] jbd2: Refactor wait logic for transaction updates
 into a common function
Message-ID: <20220113113051.5ehxl2ap3v64eyya@quack3.lan>
References: <cover.1642044249.git.riteshh@linux.ibm.com>
 <95fa94cbeb4bb0275430a6721a588bd738d5a9aa.1642044249.git.riteshh@linux.ibm.com>
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In-Reply-To: <95fa94cbeb4bb0275430a6721a588bd738d5a9aa.1642044249.git.riteshh@linux.ibm.com>
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On Thu 13-01-22 08:56:28, Ritesh Harjani wrote:
> No functionality change as such in this patch. This only refactors the
> common piece of code which waits for t_updates to finish into a common
> function named as jbd2_journal_wait_updates(journal_t *)
> 
> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>

Just one nit, otherwise. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

> @@ -1757,6 +1757,35 @@ static inline unsigned long jbd2_log_space_left(journal_t *journal)
>  	return max_t(long, free, 0);
>  }
>  
> +/*
> + * Waits for any outstanding t_updates to finish.
> + * This is called with write j_state_lock held.
> + */
> +static inline void jbd2_journal_wait_updates(journal_t *journal)
> +{
> +	transaction_t *commit_transaction = journal->j_running_transaction;
> +
> +	if (!commit_transaction)
> +		return;
> +
> +	spin_lock(&commit_transaction->t_handle_lock);
> +	while (atomic_read(&commit_transaction->t_updates)) {
> +		DEFINE_WAIT(wait);
> +
> +		prepare_to_wait(&journal->j_wait_updates, &wait,
> +					TASK_UNINTERRUPTIBLE);
> +		if (atomic_read(&commit_transaction->t_updates)) {
> +			spin_unlock(&commit_transaction->t_handle_lock);
> +			write_unlock(&journal->j_state_lock);
> +			schedule();
> +			write_lock(&journal->j_state_lock);
> +			spin_lock(&commit_transaction->t_handle_lock);
> +		}
> +		finish_wait(&journal->j_wait_updates, &wait);
> +	}
> +	spin_unlock(&commit_transaction->t_handle_lock);
> +}
> +

I don't think making this inline makes sence. Neither the commit code nor
jbd2_journal_lock_updates() are so hot that it would warrant this large
inline function...

								Honza

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