loop more
On Wed, Aug 28, 2024 at 3:29 PM zhaoyang.huang
<zhaoyang.huang@xxxxxxxxxx> wrote:
>
> From: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
>
> This patch is inspired by a code review of fs codes which aims at
> folio's extra refcnt that could introduce unwanted behavious when
> judging refcnt, such as[1]. The change relys on the policy as the
> LRU page with private data should take one corresponding refcnt.
>
> [1]
> long mapping_evict_folio(struct address_space *mapping, struct folio *folio)
> {
> ...
> //current code will misjudge here if there is one pte on the folio which
> is be deemed as the one as folio's private
> if (folio_ref_count(folio) >
> folio_nr_pages(folio) + folio_has_private(folio) + 1)
> return 0;
> if (!filemap_release_folio(folio, 0))
> return 0;
>
> return remove_mapping(mapping, folio);
> }
>
> Signed-off-by: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
> ---
> fs/nfs/write.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/fs/nfs/write.c b/fs/nfs/write.c
> index d074d0ceb4f0..80c6ded5f74c 100644
> --- a/fs/nfs/write.c
> +++ b/fs/nfs/write.c
> @@ -772,8 +772,7 @@ static void nfs_inode_add_request(struct nfs_page *req)
> nfs_lock_request(req);
> spin_lock(&mapping->i_private_lock);
> set_bit(PG_MAPPED, &req->wb_flags);
> - folio_set_private(folio);
> - folio->private = req;
> + folio_attach_private(folio, req);
> spin_unlock(&mapping->i_private_lock);
> atomic_long_inc(&nfsi->nrequests);
> /* this a head request for a page group - mark it as having an
> @@ -797,8 +796,7 @@ static void nfs_inode_remove_request(struct nfs_page *req)
>
> spin_lock(&mapping->i_private_lock);
> if (likely(folio)) {
> - folio->private = NULL;
> - folio_clear_private(folio);
> + folio_detach_private(folio);
> clear_bit(PG_MAPPED, &req->wb_head->wb_flags);
> }
> spin_unlock(&mapping->i_private_lock);
> --
> 2.25.1
>
