fscrypt: simplify bounce page handling
Currently, bounce page handling for writes to encrypted files is
unnecessarily complicated. A fscrypt_ctx is allocated along with each
bounce page, page_private(bounce_page) points to this fscrypt_ctx, and
fscrypt_ctx::w::control_page points to the original pagecache page.
However, because writes don't use the fscrypt_ctx for anything else,
there's no reason why page_private(bounce_page) can't just point to the
original pagecache page directly.
Therefore, this patch makes this change. In the process, it also cleans
up the API exposed to filesystems that allows testing whether a page is
a bounce page, getting the pagecache page from a bounce page, and
freeing a bounce page.
Reviewed-by: Chandan Rajendra <chandan@linux.ibm.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index eda4181..968ebdb 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -185,7 +185,7 @@ static void f2fs_write_end_io(struct bio *bio)
continue;
}
- fscrypt_pullback_bio_page(&page, true);
+ fscrypt_finalize_bounce_page(&page);
if (unlikely(bio->bi_status)) {
mapping_set_error(page->mapping, -EIO);
@@ -362,10 +362,9 @@ static bool __has_merged_page(struct f2fs_bio_info *io, struct inode *inode,
bio_for_each_segment_all(bvec, io->bio, iter_all) {
- if (bvec->bv_page->mapping)
- target = bvec->bv_page;
- else
- target = fscrypt_control_page(bvec->bv_page);
+ target = bvec->bv_page;
+ if (fscrypt_is_bounce_page(target))
+ target = fscrypt_pagecache_page(target);
if (inode && inode == target->mapping->host)
return true;
@@ -1900,8 +1899,7 @@ int f2fs_do_write_data_page(struct f2fs_io_info *fio)
err = f2fs_inplace_write_data(fio);
if (err) {
if (f2fs_encrypted_file(inode))
- fscrypt_pullback_bio_page(&fio->encrypted_page,
- true);
+ fscrypt_finalize_bounce_page(&fio->encrypted_page);
if (PageWriteback(page))
end_page_writeback(page);
} else {
