Re: [PATCH 1/3] block_write_full_page: Use synchronous writes for WBC_SYNC_ALL writebacks

[Jan Kara <jack@suse.cz>]

On Fri 27-03-09 16:24:29, Theodore Ts'o wrote:
> When doing synchronous writes because wbc->sync_mode is set to
> WBC_SYNC_ALL, send the write request using WRITE_SYNC, so that we
> don't unduly block system calls such as fsync().
> 
> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
  Looks sane. You can add "Acked-by: Jan Kara <jack@suse.cz>"

									Honza
> ---
>  fs/buffer.c |    5 +++--
>  1 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/buffer.c b/fs/buffer.c
> index 891e1c7..e7ebd95 100644
> --- a/fs/buffer.c
> +++ b/fs/buffer.c
> @@ -1714,6 +1714,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
>  	struct buffer_head *bh, *head;
>  	const unsigned blocksize = 1 << inode->i_blkbits;
>  	int nr_underway = 0;
> +	int write_op = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
>  
>  	BUG_ON(!PageLocked(page));
>  
> @@ -1805,7 +1806,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
>  	do {
>  		struct buffer_head *next = bh->b_this_page;
>  		if (buffer_async_write(bh)) {
> -			submit_bh(WRITE, bh);
> +			submit_bh(write_op, bh);
>  			nr_underway++;
>  		}
>  		bh = next;
> @@ -1859,7 +1860,7 @@ recover:
>  		struct buffer_head *next = bh->b_this_page;
>  		if (buffer_async_write(bh)) {
>  			clear_buffer_dirty(bh);
> -			submit_bh(WRITE, bh);
> +			submit_bh(write_op, bh);
>  			nr_underway++;
>  		}
>  		bh = next;
> -- 
> 1.5.6.3
> 
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR