* Re: bio_add_page rw mode check by merge_bvec_fn
[not found] <528E4A50.7040609@itwm.fraunhofer.de>
@ 2013-11-21 18:08 ` Bernd Schubert
2013-11-22 15:36 ` Christoph Hellwig
0 siblings, 1 reply; 3+ messages in thread
From: Bernd Schubert @ 2013-11-21 18:08 UTC (permalink / raw)
To: linux-fsdevel@vger.kernel.org, xfs, linux-ext4
Cc: Kent Overstreet, NeilBrown, Jens Axboe
[CCing linux-fsdevel instead of accidental fhgfs cc]
On 11/21/2013 07:00 PM, Bernd Schubert wrote:
> Hi all,
>
> raid5_mergeable_bvec() (q->merge_bvec_fn) checks for the rw-type and
> makes decisions based on that if the bio is mergable or not. But so far
> this value is only initialized on calling submit_bio(),
> at least not by ext4 and xfs. I have not checked other file system so far.
>
> Question 1: merge_bvec_fn is supposed to be removed, is is
> still worth to fix the usage of merge_bvec_fn?
>
> Question 2: If it is still supposed to be fixed, how do want to have
> it? So far I have two patches for xfs and ext4 to set the rw type
> directly there, but maybe bio_add_page should get an int rw_type
> parameter and set bio->bi_rw itself?
>
>
>
> diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
> index d488f80..4cddc15 100644
> --- a/fs/ext4/page-io.c
> +++ b/fs/ext4/page-io.c
> @@ -370,6 +370,7 @@ static int io_submit_init_bio(struct ext4_io_submit *io,
> bio->bi_bdev = bh->b_bdev;
> bio->bi_end_io = ext4_end_bio;
> bio->bi_private = ext4_get_io_end(io->io_end);
> + bio->bi_rw |= io->io_op;
> io->io_bio = bio;
> io->io_next_block = bh->b_blocknr;
> return 0;
>
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index 71c8c9d..b48048f 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -401,7 +401,8 @@ xfs_submit_ioend_bio(
>
> STATIC struct bio *
> xfs_alloc_ioend_bio(
> - struct buffer_head *bh)
> + struct buffer_head *bh,
> + struct writeback_control *wbc)
> {
> int nvecs = bio_get_nr_vecs(bh->b_bdev);
> struct bio *bio = bio_alloc(GFP_NOIO, nvecs);
> @@ -409,6 +410,7 @@ xfs_alloc_ioend_bio(
> ASSERT(bio->bi_private == NULL);
> bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
> bio->bi_bdev = bh->b_bdev;
> + bio->bi_rw |= (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : WRITE;
> return bio;
> }
>
> @@ -511,7 +513,8 @@ xfs_submit_ioend(
>
> if (!bio) {
> retry:
> - bio = xfs_alloc_ioend_bio(bh);
> + bio = xfs_alloc_ioend_bio(bh, wbc);
> +
> } else if (bh->b_blocknr != lastblock + 1) {
> xfs_submit_ioend_bio(wbc, ioend, bio);
> goto retry;
>
>
>
> Thanks,
> Bernd
>
^ permalink raw reply [flat|nested] 3+ messages in thread