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

Jan Kara
2009-03-27T20:55:58Z

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