On Mon, Feb 10, 2025 at 2:35 PM Matthew Wilcox (Oracle)
<willy@xxxxxxxxxxxxx> wrote:
> gfs2_end_log_write() has to handle bios which consist of both pages
> which belong to folios and pages which were allocated from a mempool and
> do not belong to a folio. It would be cleaner to have separate endio
> handlers which handle each type, but it's not clear to me whether that's
> even possible.
>
> This patch is slightly forward-looking in that page_folio() cannot
> currently return NULL, but it will return NULL in the future for pages
> which do not belong to a folio.
>
> This was the last user of page_has_buffers(), so remove it.
Right now in for-next, ocfs2 is still using page_has_buffers(), so I'm
going to skip this part.
Thanks,
Andreas
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
> fs/gfs2/lops.c | 28 ++++++++++++++--------------
> include/linux/buffer_head.h | 1 -
> 2 files changed, 14 insertions(+), 15 deletions(-)
>
> diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
> index 30597b0f7cc3..8b46bd01a448 100644
> --- a/fs/gfs2/lops.c
> +++ b/fs/gfs2/lops.c
> @@ -157,7 +157,9 @@ u64 gfs2_log_bmap(struct gfs2_jdesc *jd, unsigned int lblock)
> /**
> * gfs2_end_log_write_bh - end log write of pagecache data with buffers
> * @sdp: The superblock
> - * @bvec: The bio_vec
> + * @folio: The folio
> + * @offset: The first byte within the folio that completed
> + * @size: The number of bytes that completed
> * @error: The i/o status
> *
> * This finds the relevant buffers and unlocks them and sets the
> @@ -166,17 +168,13 @@ u64 gfs2_log_bmap(struct gfs2_jdesc *jd, unsigned int lblock)
> * that is pinned in the pagecache.
> */
>
> -static void gfs2_end_log_write_bh(struct gfs2_sbd *sdp,
> - struct bio_vec *bvec,
> - blk_status_t error)
> +static void gfs2_end_log_write_bh(struct gfs2_sbd *sdp, struct folio *folio,
> + size_t offset, size_t size, blk_status_t error)
> {
> struct buffer_head *bh, *next;
> - struct page *page = bvec->bv_page;
> - unsigned size;
>
> - bh = page_buffers(page);
> - size = bvec->bv_len;
> - while (bh_offset(bh) < bvec->bv_offset)
> + bh = folio_buffers(folio);
> + while (bh_offset(bh) < offset)
> bh = bh->b_this_page;
> do {
> if (error)
> @@ -186,7 +184,7 @@ static void gfs2_end_log_write_bh(struct gfs2_sbd *sdp,
> size -= bh->b_size;
> brelse(bh);
> bh = next;
> - } while(bh && size);
> + } while (bh && size);
> }
>
> /**
> @@ -203,7 +201,6 @@ static void gfs2_end_log_write(struct bio *bio)
> {
> struct gfs2_sbd *sdp = bio->bi_private;
> struct bio_vec *bvec;
> - struct page *page;
> struct bvec_iter_all iter_all;
>
> if (bio->bi_status) {
> @@ -217,9 +214,12 @@ static void gfs2_end_log_write(struct bio *bio)
> }
>
> bio_for_each_segment_all(bvec, bio, iter_all) {
> - page = bvec->bv_page;
> - if (page_has_buffers(page))
> - gfs2_end_log_write_bh(sdp, bvec, bio->bi_status);
> + struct page *page = bvec->bv_page;
> + struct folio *folio = page_folio(page);
> +
> + if (folio && folio_buffers(folio))
> + gfs2_end_log_write_bh(sdp, folio, bvec->bv_offset,
> + bvec->bv_len, bio->bi_status);
> else
> mempool_free(page, gfs2_page_pool);
> }
> diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
> index 932139c5d46f..fab70b26e131 100644
> --- a/include/linux/buffer_head.h
> +++ b/include/linux/buffer_head.h
> @@ -182,7 +182,6 @@ static inline unsigned long bh_offset(const struct buffer_head *bh)
> BUG_ON(!PagePrivate(page)); \
> ((struct buffer_head *)page_private(page)); \
> })
> -#define page_has_buffers(page) PagePrivate(page)
> #define folio_buffers(folio) folio_get_private(folio)
>
> void buffer_check_dirty_writeback(struct folio *folio,
> --
> 2.47.2
>
