Hi Chao,
On Thu, Jun 18, 2020 at 06:06:02PM +0800, Chao Yu wrote:
> > @@ -936,8 +972,11 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
> >
> > inc_page_count(sbi, WB_DATA_TYPE(bio_page));
> >
> > - if (io->bio && !io_is_mergeable(sbi, io->bio, io, fio,
> > - io->last_block_in_bio, fio->new_blkaddr))
> > + if (io->bio &&
> > + (!io_is_mergeable(sbi, io->bio, io, fio, io->last_block_in_bio,
> > + fio->new_blkaddr) ||
> > + !f2fs_crypt_mergeable_bio(io->bio, fio->page->mapping->host,
> > + fio->page->index, fio)))
>
> bio_page->index, fio)))
>
> > __submit_merged_bio(io);
> > alloc_new:
> > if (io->bio == NULL) {
> > @@ -949,6 +988,8 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
> > goto skip;
> > }
> > io->bio = __bio_alloc(fio, BIO_MAX_PAGES);
> > + f2fs_set_bio_crypt_ctx(io->bio, fio->page->mapping->host,
> > + fio->page->index, fio, GFP_NOIO);
>
> bio_page->index, fio, GFP_NOIO);
>
We're using ->mapping->host and ->index. Ordinarily that would mean the page
needs to be a pagecache page. But bio_page can also be a compressed page or a
bounce page containing fs-layer encrypted contents.
Is your suggestion to keep using fio->page->mapping->host (since encrypted pages
don't have a mapping), but start using bio_page->index (since f2fs apparently
*does* set ->index for compressed pages, and if the file uses fs-layer
encryption then f2fs_set_bio_crypt_ctx() won't use the index anyway)?
Does this mean the code is currently broken for compression + inline encryption
because it's using the wrong ->index? I think the answer is no, since
f2fs_write_compressed_pages() will still pass the first 'nr_cpages' pagecache
pages along with the compressed pages. In that case, your suggestion would be a
cleanup rather than a fix?
It would be helpful if there was an f2fs mount option to auto-enable compression
on all files (similar to how test_dummy_encryption auto-enables encryption on
all files) so that it could be tested more easily.
- Eric
