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SubjectRe: [f2fs-dev] [PATCH 4/4] f2fs: should check the type of end_io after pullback by fscrypto
On 07/09, Chao Yu wrote:
> On 2018/7/7 5:09, Jaegeuk Kim wrote:
> > This fixes to get the page type after pullback by fscrypto, since the original
> > page is bounce page but we should need to get control page which is what we
> > originally submitted.
> >
> > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> > ---
> > fs/f2fs/data.c | 5 ++---
> > 1 file changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index c3f9b9baf140..9a0fcec53d0e 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -152,7 +152,6 @@ static void f2fs_write_end_io(struct bio *bio)
> >
> > bio_for_each_segment_all(bvec, bio, i) {
> > struct page *page = bvec->bv_page;
> > - enum count_type type = WB_DATA_TYPE(page);
> >
> > if (IS_DUMMY_WRITTEN_PAGE(page)) {
> > set_page_private(page, (unsigned long)NULL);
> > @@ -169,14 +168,14 @@ static void f2fs_write_end_io(struct bio *bio)
> >
> > if (unlikely(bio->bi_status)) {
> > mapping_set_error(page->mapping, -EIO);
> > - if (type == F2FS_WB_CP_DATA)
> > + if (WB_DATA_TYPE(page) == F2FS_WB_CP_DATA)
> > f2fs_stop_checkpoint(sbi, true);
> > }
> >
> > f2fs_bug_on(sbi, page->mapping == NODE_MAPPING(sbi) &&
> > page->index != nid_of_node(page));
> >
> > - dec_page_count(sbi, type);
> > + dec_page_count(sbi, WB_DATA_TYPE(page));
>
> But we account F2FS_WB_CP_DATA/F2FS_WB_DATA type page based bounce page instead
> of original page.
>
> bio_page = fio->encrypted_page ? fio->encrypted_page : fio->page;
>
> /* set submitted = true as a return value */
> fio->submitted = true;
>
> inc_page_count(sbi, WB_DATA_TYPE(bio_page));
>
> Because for encrypted page of regular inode, we should account it with
> F2FS_WB_DATA type:
>
> static bool __is_cp_guaranteed(struct page *page)
> {
> ....
> if (!mapping) <---bounce page's mapping is NULL
> return false;
> }
>
> So we will get F2FS_WB_DATA type from __is_cp_guaranteed below:
>
> enum count_type type = WB_DATA_TYPE(page);
>
> Is there any problem?

Wait a minute.

bio_page = fio->encrypted_page ? fio->encrypted_page : fio->page;

1. fio->encrypted_page

inc_page_count(sbi, F2FS_WB_CP_DATA); // page->mapping == META_MAPPING

In write_end_io(),
type = F2FS_WB_DATA; // page->mapping == NULL
fscrypt_pullback_bio_page(&page);
page = fio->encrypted_page;

dec_page_count(F2FS_WB_DATA);

2. fio->page

inc_page_count(sbi, F2FS_WB_DATA);

In write_end_io(),
type = F2FS_WB_DATA; // page->mapping == NULL
fscrypt_pullback_bio_page(&page);
page = fio->encrypted_page;

dec_page_count(F2FS_WB_DATA);

Thoughts?

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