On Mon, Nov 26, 2018 at 10:17:01AM +0800, Ming Lei wrote:
> From: Christoph Hellwig <hch@xxxxxx>
>
> The btrfs write path passes a bio_offset argument through some deep
> callchains including async offloading. In the end this is easily
> calculatable using page_offset plus the bvec offset for the first
> page in the bio, and only actually used by by a single function.
> Just move the calculation of the offset there.
>
> Reviewed-by: David Sterba <dsterba@xxxxxxxx>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> fs/btrfs/disk-io.c | 21 +++++----------------
> fs/btrfs/disk-io.h | 2 +-
> fs/btrfs/extent_io.c | 9 ++-------
> fs/btrfs/extent_io.h | 5 ++---
> fs/btrfs/inode.c | 17 ++++++++---------
> 5 files changed, 18 insertions(+), 36 deletions(-)
[snip]
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 9ea4c6f0352f..c576b3fcaea7 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -1920,8 +1920,7 @@ int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
> * At IO completion time the cums attached on the ordered extent record
> * are inserted into the btree
> */
> -static blk_status_t btrfs_submit_bio_start(void *private_data, struct bio *bio,
> - u64 bio_offset)
> +static blk_status_t btrfs_submit_bio_start(void *private_data, struct bio *bio)
> {
> struct inode *inode = private_data;
> blk_status_t ret = 0;
> @@ -1973,8 +1972,7 @@ blk_status_t btrfs_submit_bio_done(void *private_data, struct bio *bio,
> * c-3) otherwise: async submit
> */
> static blk_status_t btrfs_submit_bio_hook(void *private_data, struct bio *bio,
> - int mirror_num, unsigned long bio_flags,
> - u64 bio_offset)
> + int mirror_num, unsigned long bio_flags)
> {
> struct inode *inode = private_data;
> struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> @@ -2011,8 +2009,7 @@ static blk_status_t btrfs_submit_bio_hook(void *private_data, struct bio *bio,
> goto mapit;
> /* we're doing a write, do the async checksumming */
> ret = btrfs_wq_submit_bio(fs_info, bio, mirror_num, bio_flags,
> - bio_offset, inode,
> - btrfs_submit_bio_start);
> + inode, btrfs_submit_bio_start);
> goto out;
> } else if (!skip_sum) {
> ret = btrfs_csum_one_bio(inode, bio, 0, 0);
> @@ -8123,10 +8120,13 @@ static void btrfs_endio_direct_write(struct bio *bio)
> }
>
> static blk_status_t btrfs_submit_bio_start_direct_io(void *private_data,
> - struct bio *bio, u64 offset)
> + struct bio *bio)
> {
> struct inode *inode = private_data;
> + struct bio_vec *bvec = bio_first_bvec_all(bio);
> + u64 offset = page_offset(bvec->bv_page) + bvec->bv_offset;
Hm, but for direct I/O, these will be user pages (or the zero page), so
page_offset() won't be valid?
> blk_status_t ret;
> +
> ret = btrfs_csum_one_bio(inode, bio, offset, 1);
> BUG_ON(ret); /* -ENOMEM */
> return 0;
