linux-kernel - Re: [PATCH v2 1/2] f2fs: Apply bio flags to direct I/O

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Message-ID: <0f09a845-fbaf-4ddf-b684-a1182f85a9ff@kernel.org>
Date: Mon, 16 Jun 2025 20:41:20 +0800
From: Chao Yu <chao@...nel.org>
To: Daniel Lee <chullee@...gle.com>, Jaegeuk Kim <jaegeuk@...nel.org>
Cc: chao@...nel.org, linux-f2fs-devel@...ts.sourceforge.net,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] f2fs: Apply bio flags to direct I/O

On 6/15/25 22:42, Daniel Lee wrote:
> Bio flags like REQ_PRIO, REQ_META, and REQ_FUA, determined by
> f2fs_io_flags(), were not being applied to direct I/O (DIO) writes.
> This meant that DIO writes would not respect filesystem-level hints
> (for REQ_META/FUA) or inode-level hints (like F2FS_IOPRIO_WRITE).
> 
> This patch refactors f2fs_io_flags() to use a direct inode pointer
> instead of deriving it from a page. The function is then called from
> the DIO write path, ensuring that bio flags are handled consistently
> for both buffered and DIO writes.
> 
> Signed-off-by: Daniel Lee <chullee@...gle.com>
> ---
>  fs/f2fs/data.c | 10 +++++-----
>  fs/f2fs/f2fs.h |  1 +
>  fs/f2fs/file.c | 11 +++++++++++
>  3 files changed, 17 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 31e892842625..71dde494b892 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -416,10 +416,9 @@ int f2fs_target_device_index(struct f2fs_sb_info *sbi, block_t blkaddr)
>  	return 0;
>  }
>  
> -static blk_opf_t f2fs_io_flags(struct f2fs_io_info *fio)
> +blk_opf_t f2fs_io_flags(struct f2fs_io_info *fio, struct inode *inode)
>  {
>  	unsigned int temp_mask = GENMASK(NR_TEMP_TYPE - 1, 0);
> -	struct folio *fio_folio = page_folio(fio->page);
>  	unsigned int fua_flag, meta_flag, io_flag;
>  	blk_opf_t op_flags = 0;
>  
> @@ -446,8 +445,8 @@ static blk_opf_t f2fs_io_flags(struct f2fs_io_info *fio)
>  	if (BIT(fio->temp) & fua_flag)
>  		op_flags |= REQ_FUA;
>  
> -	if (fio->type == DATA &&
> -	    F2FS_I(fio_folio->mapping->host)->ioprio_hint == F2FS_IOPRIO_WRITE)
> +	if (inode && fio->type == DATA &&
> +	    F2FS_I(inode)->ioprio_hint == F2FS_IOPRIO_WRITE)
>  		op_flags |= REQ_PRIO;
>  
>  	return op_flags;
> @@ -459,10 +458,11 @@ static struct bio *__bio_alloc(struct f2fs_io_info *fio, int npages)
>  	struct block_device *bdev;
>  	sector_t sector;
>  	struct bio *bio;
> +	struct inode *inode = fio->page ? fio->page->mapping->host : NULL;

fio->page will always be true now? We can pass fio->page->mapping->host to f2fs_io_flags()
directly?

Thanks,

>  
>  	bdev = f2fs_target_device(sbi, fio->new_blkaddr, &sector);
>  	bio = bio_alloc_bioset(bdev, npages,
> -				fio->op | fio->op_flags | f2fs_io_flags(fio),
> +				fio->op | fio->op_flags | f2fs_io_flags(fio, inode),
>  				GFP_NOIO, &f2fs_bioset);
>  	bio->bi_iter.bi_sector = sector;
>  	if (is_read_io(fio->op)) {
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 9333a22b9a01..3e02687c1b58 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -3972,6 +3972,7 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio);
>  struct block_device *f2fs_target_device(struct f2fs_sb_info *sbi,
>  		block_t blk_addr, sector_t *sector);
>  int f2fs_target_device_index(struct f2fs_sb_info *sbi, block_t blkaddr);
> +blk_opf_t f2fs_io_flags(struct f2fs_io_info *fio, struct inode *inode);
>  void f2fs_set_data_blkaddr(struct dnode_of_data *dn, block_t blkaddr);
>  void f2fs_update_data_blkaddr(struct dnode_of_data *dn, block_t blkaddr);
>  int f2fs_reserve_new_blocks(struct dnode_of_data *dn, blkcnt_t count);
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 696131e655ed..3eb40d7bf602 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -5015,6 +5015,17 @@ static void f2fs_dio_write_submit_io(const struct iomap_iter *iter,
>  	enum log_type type = f2fs_rw_hint_to_seg_type(sbi, inode->i_write_hint);
>  	enum temp_type temp = f2fs_get_segment_temp(sbi, type);
>  
> +	/* if fadvise set to hot, override the temperature */
> +	struct f2fs_io_info fio = {
> +		.sbi = sbi,
> +		.type = DATA,
> +		.op = REQ_OP_WRITE,
> +		.temp = file_is_hot(inode) ? HOT : temp,
> +		.op_flags = bio->bi_opf,
> +		.page = NULL,
> +	};
> +	bio->bi_opf |= f2fs_io_flags(&fio, inode);
> +
>  	bio->bi_write_hint = f2fs_io_type_to_rw_hint(sbi, DATA, temp);
>  	submit_bio(bio);
>  }