linux-ext4 - Re: [PATCH] fs: Make wbc_to_tag() extern and use it in fs.

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Message-ID: <f8cf2061-44f3-4775-b321-713dc90c3282@suse.com>
Date: Mon, 29 Sep 2025 19:45:18 +0930
From: Qu Wenruo <wqu@...e.com>
To: Julian Sun <sunjunchao@...edance.com>, linux-fsdevel@...r.kernel.org,
 linux-f2fs-devel@...ts.sourceforge.net, linux-ext4@...r.kernel.org,
 ceph-devel@...r.kernel.org, linux-btrfs@...r.kernel.org
Cc: clm@...com, dsterba@...e.com, xiubli@...hat.com, idryomov@...il.com,
 tytso@....edu, adilger.kernel@...ger.ca, jaegeuk@...nel.org,
 chao@...nel.org, willy@...radead.org, jack@...e.cz, brauner@...nel.org,
 agruenba@...hat.com
Subject: Re: [PATCH] fs: Make wbc_to_tag() extern and use it in fs.



在 2025/9/29 19:25, Julian Sun 写道:
> The logic in wbc_to_tag() is widely used in file systems, so modify this
> function to be extern and use it in file systems.
> 
> This patch has only passed compilation tests, but it should be fine.
> 
> Signed-off-by: Julian Sun <sunjunchao@...edance.com>
> ---
>   fs/btrfs/extent_io.c      | 5 +----
>   fs/ceph/addr.c            | 6 +-----
>   fs/ext4/inode.c           | 5 +----
>   fs/f2fs/data.c            | 5 +----
>   fs/gfs2/aops.c            | 5 +----
>   include/linux/writeback.h | 1 +
>   mm/page-writeback.c       | 2 +-
>   7 files changed, 7 insertions(+), 22 deletions(-)
> 
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index b21cb72835cc..0fea58287175 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -2390,10 +2390,7 @@ static int extent_write_cache_pages(struct address_space *mapping,
>   			       &BTRFS_I(inode)->runtime_flags))
>   		wbc->tagged_writepages = 1;
>   
> -	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
> -		tag = PAGECACHE_TAG_TOWRITE;
> -	else
> -		tag = PAGECACHE_TAG_DIRTY;
> +	tag = wbc_to_tag(wbc);
>   retry:
>   	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
>   		tag_pages_for_writeback(mapping, index, end);
> diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
> index 322ed268f14a..63b75d214210 100644
> --- a/fs/ceph/addr.c
> +++ b/fs/ceph/addr.c
> @@ -1045,11 +1045,7 @@ void ceph_init_writeback_ctl(struct address_space *mapping,
>   	ceph_wbc->index = ceph_wbc->start_index;
>   	ceph_wbc->end = -1;
>   
> -	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) {
> -		ceph_wbc->tag = PAGECACHE_TAG_TOWRITE;
> -	} else {
> -		ceph_wbc->tag = PAGECACHE_TAG_DIRTY;
> -	}
> +	ceph_wbc->tag = wbc_to_tag(wbc);
>   
>   	ceph_wbc->op_idx = -1;
>   	ceph_wbc->num_ops = 0;
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 5b7a15db4953..196eba7fa39c 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -2619,10 +2619,7 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
>   	handle_t *handle = NULL;
>   	int bpp = ext4_journal_blocks_per_folio(mpd->inode);
>   
> -	if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
> -		tag = PAGECACHE_TAG_TOWRITE;
> -	else
> -		tag = PAGECACHE_TAG_DIRTY;
> +	tag = wbc_to_tag(mpd->wbc);
>   
>   	mpd->map.m_len = 0;
>   	mpd->next_pos = mpd->start_pos;
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 7961e0ddfca3..101e962845db 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -3003,10 +3003,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
>   		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
>   			range_whole = 1;
>   	}
> -	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
> -		tag = PAGECACHE_TAG_TOWRITE;
> -	else
> -		tag = PAGECACHE_TAG_DIRTY;
> +	tag = wbc_to_tag(wbc);
>   retry:
>   	retry = 0;
>   	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
> diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
> index 47d74afd63ac..12394fc5dd29 100644
> --- a/fs/gfs2/aops.c
> +++ b/fs/gfs2/aops.c
> @@ -311,10 +311,7 @@ static int gfs2_write_cache_jdata(struct address_space *mapping,
>   			range_whole = 1;
>   		cycled = 1; /* ignore range_cyclic tests */
>   	}
> -	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
> -		tag = PAGECACHE_TAG_TOWRITE;
> -	else
> -		tag = PAGECACHE_TAG_DIRTY;
> +	tag = wbc_to_tag(wbc);
>   
>   retry:
>   	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
> diff --git a/include/linux/writeback.h b/include/linux/writeback.h
> index a2848d731a46..884811596e10 100644
> --- a/include/linux/writeback.h
> +++ b/include/linux/writeback.h
> @@ -370,6 +370,7 @@ int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
>   void writeback_set_ratelimit(void);
>   void tag_pages_for_writeback(struct address_space *mapping,
>   			     pgoff_t start, pgoff_t end);
> +xa_mark_t wbc_to_tag(struct writeback_control *wbc);
>   
>   bool filemap_dirty_folio(struct address_space *mapping, struct folio *folio);
>   bool folio_redirty_for_writepage(struct writeback_control *, struct folio *);
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 3e248d1c3969..243808e19445 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -2434,7 +2434,7 @@ static bool folio_prepare_writeback(struct address_space *mapping,
>   	return true;
>   }
>   
> -static xa_mark_t wbc_to_tag(struct writeback_control *wbc)
> +xa_mark_t wbc_to_tag(struct writeback_control *wbc)

The function is small enough, why not export it as an inline function?

The current version also lacks EXPORT_SYMBOL(), it may cause problems 
for fses built as a module.

Thanks,
Qu

>   {
>   	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
>   		return PAGECACHE_TAG_TOWRITE;