linux-ext4 - Re: [PATCH 2/3] ext3: Use WRITE_SYNC for commits which are caused by fsync()

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Message-ID: <20090327222017.GI31071@duck.suse.cz>
Date:	Fri, 27 Mar 2009 23:20:17 +0100
From:	Jan Kara <jack@...e.cz>
To:	Theodore Ts'o <tytso@....edu>
Cc:	Linux Kernel Developers List <linux-kernel@...r.kernel.org>,
	Ext4 Developers List <linux-ext4@...r.kernel.org>,
	jack@...e.cz
Subject: Re: [PATCH 2/3] ext3: Use WRITE_SYNC for commits which are caused
	by fsync()

On Fri 27-03-09 16:24:30, Theodore Ts'o wrote:
> If a commit is triggered by fsync(), set a flag indicating the journal
> blocks associated with the transaction should be flushed out using
> WRITE_SYNC.
> 
> Signed-off-by: "Theodore Ts'o" <tytso@....edu>
  And this one seems fine as well. Acked-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  fs/jbd/commit.c      |   23 +++++++++++++++--------
>  fs/jbd/transaction.c |    2 ++
>  include/linux/jbd.h  |    5 +++++
>  3 files changed, 22 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
> index 3fbffb1..f8077b9 100644
> --- a/fs/jbd/commit.c
> +++ b/fs/jbd/commit.c
> @@ -20,6 +20,7 @@
>  #include <linux/slab.h>
>  #include <linux/mm.h>
>  #include <linux/pagemap.h>
> +#include <linux/bio.h>
>  
>  /*
>   * Default IO end handler for temporary BJ_IO buffer_heads.
> @@ -171,14 +172,15 @@ static int journal_write_commit_record(journal_t *journal,
>  	return (ret == -EIO);
>  }
>  
> -static void journal_do_submit_data(struct buffer_head **wbuf, int bufs)
> +static void journal_do_submit_data(struct buffer_head **wbuf, int bufs,
> +				   int write_op)
>  {
>  	int i;
>  
>  	for (i = 0; i < bufs; i++) {
>  		wbuf[i]->b_end_io = end_buffer_write_sync;
>  		/* We use-up our safety reference in submit_bh() */
> -		submit_bh(WRITE, wbuf[i]);
> +		submit_bh(write_op, wbuf[i]);
>  	}
>  }
>  
> @@ -186,7 +188,8 @@ static void journal_do_submit_data(struct buffer_head **wbuf, int bufs)
>   *  Submit all the data buffers to disk
>   */
>  static int journal_submit_data_buffers(journal_t *journal,
> -				transaction_t *commit_transaction)
> +				       transaction_t *commit_transaction,
> +				       int write_op)
>  {
>  	struct journal_head *jh;
>  	struct buffer_head *bh;
> @@ -225,7 +228,7 @@ write_out_data:
>  				BUFFER_TRACE(bh, "needs blocking lock");
>  				spin_unlock(&journal->j_list_lock);
>  				/* Write out all data to prevent deadlocks */
> -				journal_do_submit_data(wbuf, bufs);
> +				journal_do_submit_data(wbuf, bufs, write_op);
>  				bufs = 0;
>  				lock_buffer(bh);
>  				spin_lock(&journal->j_list_lock);
> @@ -256,7 +259,7 @@ write_out_data:
>  			jbd_unlock_bh_state(bh);
>  			if (bufs == journal->j_wbufsize) {
>  				spin_unlock(&journal->j_list_lock);
> -				journal_do_submit_data(wbuf, bufs);
> +				journal_do_submit_data(wbuf, bufs, write_op);
>  				bufs = 0;
>  				goto write_out_data;
>  			}
> @@ -286,7 +289,7 @@ write_out_data:
>  		}
>  	}
>  	spin_unlock(&journal->j_list_lock);
> -	journal_do_submit_data(wbuf, bufs);
> +	journal_do_submit_data(wbuf, bufs, write_op);
>  
>  	return err;
>  }
> @@ -315,6 +318,7 @@ void journal_commit_transaction(journal_t *journal)
>  	int first_tag = 0;
>  	int tag_flag;
>  	int i;
> +	int write_op = WRITE;
>  
>  	/*
>  	 * First job: lock down the current transaction and wait for
> @@ -347,6 +351,8 @@ void journal_commit_transaction(journal_t *journal)
>  	spin_lock(&journal->j_state_lock);
>  	commit_transaction->t_state = T_LOCKED;
>  
> +	if (commit_transaction->t_synchronous_commit)
> +		write_op = WRITE_SYNC;
>  	spin_lock(&commit_transaction->t_handle_lock);
>  	while (commit_transaction->t_updates) {
>  		DEFINE_WAIT(wait);
> @@ -431,7 +437,8 @@ void journal_commit_transaction(journal_t *journal)
>  	 * Now start flushing things to disk, in the order they appear
>  	 * on the transaction lists.  Data blocks go first.
>  	 */
> -	err = journal_submit_data_buffers(journal, commit_transaction);
> +	err = journal_submit_data_buffers(journal, commit_transaction,
> +					  write_op);
>  
>  	/*
>  	 * Wait for all previously submitted IO to complete.
> @@ -660,7 +667,7 @@ start_journal_io:
>  				clear_buffer_dirty(bh);
>  				set_buffer_uptodate(bh);
>  				bh->b_end_io = journal_end_buffer_io_sync;
> -				submit_bh(WRITE, bh);
> +				submit_bh(write_op, bh);
>  			}
>  			cond_resched();
>  
> diff --git a/fs/jbd/transaction.c b/fs/jbd/transaction.c
> index e6a1174..ed886e6 100644
> --- a/fs/jbd/transaction.c
> +++ b/fs/jbd/transaction.c
> @@ -1440,6 +1440,8 @@ int journal_stop(handle_t *handle)
>  		}
>  	}
>  
> +	if (handle->h_sync)
> +		transaction->t_synchronous_commit = 1;
>  	current->journal_info = NULL;
>  	spin_lock(&journal->j_state_lock);
>  	spin_lock(&transaction->t_handle_lock);
> diff --git a/include/linux/jbd.h b/include/linux/jbd.h
> index 64246dc..2c69431 100644
> --- a/include/linux/jbd.h
> +++ b/include/linux/jbd.h
> @@ -552,6 +552,11 @@ struct transaction_s
>  	 */
>  	int t_handle_count;
>  
> +	/*
> +	 * This transaction is being forced and some process is
> +	 * waiting for it to finish.
> +	 */
> +	int t_synchronous_commit:1;
>  };
>  
>  /**
> -- 
> 1.5.6.3
> 
-- 
Jan Kara <jack@...e.cz>
SUSE Labs, CR
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