Hi Chandan,
On Fri, Jan 12, 2018 at 07:41:24PM +0530, Chandan Rajendra wrote:
> With blocksize < pagesize, a page can contain more than one block. Hence
> this commit changes completion_pages() to invoke fscrypt_decrypt_page()
> in order to decrypt all the contiguous blocks mapped by the page.
>
> Signed-off-by: Chandan Rajendra <chandan@xxxxxxxxxxxxxxxxxx>
> ---
> fs/crypto/bio.c | 19 +++++++++++++++++--
> 1 file changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
> index 0d5e6a5..eb6e06a 100644
> --- a/fs/crypto/bio.c
> +++ b/fs/crypto/bio.c
> @@ -40,8 +40,23 @@ static void completion_pages(struct work_struct *work)
>
> bio_for_each_segment_all(bv, bio, i) {
> struct page *page = bv->bv_page;
> - int ret = fscrypt_decrypt_page(page->mapping->host, page,
> - PAGE_SIZE, 0, page->index);
> + struct inode *inode = page->mapping->host;
> + const unsigned long blocksize = inode->i_sb->s_blocksize;
> + const unsigned blkbits = inode->i_blkbits;
> + int page_blk = page->index << (PAGE_SHIFT - blkbits);
> + int blk = page_blk + (bv->bv_offset >> blkbits);
Use 'u64' for the block number:
u64 page_blk = (u64)page->index << (PAGE_SHIFT - blkbits);
u64 blk = page_blk + (bv->bv_offset >> blkbits);
> + int nr_blks = bv->bv_len >> blkbits;
> + int ret = 0;
> + int j;
> +
> + for (j = 0; j < nr_blks; j++, blk++) {
> + ret = fscrypt_decrypt_page(page->mapping->host,
> + page, blocksize,
> + bv->bv_offset + (j << blkbits),
> + blk);
> + if (ret)
> + break;
> + }
>
> if (ret) {
> WARN_ON_ONCE(1);
Since that we'll now actually be operating on blocks rather than pages, some
renaming seems to be in order, otherwise things will get very confusing. e.g.:
fscrypt_decrypt_page() -> fscrypt_decrypt_block()
fscrypt_encrypt_page() -> fscrypt_encrypt_block()
completion_pages() -> completion_blocks()
fscrypt_decrypt_bio_pages() -> fscrypt_decrypt_bio_blocks()
Please also update the comment for completion_pages() / completion_blocks() to
clarify that it is decrypting *blocks*, not *pages*.
(Yes, we should have named all these functions as *_block() originally. But
this is a good time to fix it!)
Eric
