On Sun, Apr 28, 2019 at 10:01:20AM +0530, Chandan Rajendra wrote:
> For subpage-sized blocks, this commit adds code to encrypt all zeroed
> out blocks mapped by a page.
>
> Signed-off-by: Chandan Rajendra <chandan@xxxxxxxxxxxxx>
> ---
> fs/crypto/bio.c | 40 ++++++++++++++++++----------------------
> 1 file changed, 18 insertions(+), 22 deletions(-)
>
> diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
> index 856f4694902d..46dd2ec50c7d 100644
> --- a/fs/crypto/bio.c
> +++ b/fs/crypto/bio.c
> @@ -108,29 +108,23 @@ EXPORT_SYMBOL(fscrypt_pullback_bio_page);
> int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
> sector_t pblk, unsigned int len)
> {
> - struct fscrypt_ctx *ctx;
> struct page *ciphertext_page = NULL;
> struct bio *bio;
> + u64 total_bytes, page_bytes;
page_bytes should be 'unsigned int', since it's <= PAGE_SIZE.
> int ret, err = 0;
>
> - BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE);
> -
> - ctx = fscrypt_get_ctx(inode, GFP_NOFS);
> - if (IS_ERR(ctx))
> - return PTR_ERR(ctx);
> + total_bytes = len << inode->i_blkbits;
Should cast len to 'u64' here, in case it's greater than UINT_MAX / blocksize.
>
> - ciphertext_page = fscrypt_alloc_bounce_page(ctx, GFP_NOWAIT);
> - if (IS_ERR(ciphertext_page)) {
> - err = PTR_ERR(ciphertext_page);
> - goto errout;
> - }
> + while (total_bytes) {
> + page_bytes = min_t(u64, total_bytes, PAGE_SIZE);
>
> - while (len--) {
> - err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk,
> - ZERO_PAGE(0), ciphertext_page,
> - PAGE_SIZE, 0, GFP_NOFS);
> - if (err)
> + ciphertext_page = fscrypt_encrypt_page(inode, ZERO_PAGE(0),
> + page_bytes, 0, lblk, GFP_NOFS);
> + if (IS_ERR(ciphertext_page)) {
> + err = PTR_ERR(ciphertext_page);
> + ciphertext_page = NULL;
> goto errout;
> + }
'ciphertext_page' is leaked after each loop iteration. Did you mean to free it,
or did you mean to reuse it for subsequent iterations?
>
> bio = bio_alloc(GFP_NOWAIT, 1);
> if (!bio) {
> @@ -141,9 +135,8 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
> bio->bi_iter.bi_sector =
> pblk << (inode->i_sb->s_blocksize_bits - 9);
This line uses ->s_blocksize_bits, but your new code uses ->i_blkbits. AFAIK
they'll always be the same, but please pick one or the other to use.
> bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
> - ret = bio_add_page(bio, ciphertext_page,
> - inode->i_sb->s_blocksize, 0);
> - if (ret != inode->i_sb->s_blocksize) {
> + ret = bio_add_page(bio, ciphertext_page, page_bytes, 0);
> + if (ret != page_bytes) {
> /* should never happen! */
> WARN_ON(1);
> bio_put(bio);
> @@ -156,12 +149,15 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
> bio_put(bio);
> if (err)
> goto errout;
> - lblk++;
> - pblk++;
> +
> + lblk += page_bytes >> inode->i_blkbits;
> + pblk += page_bytes >> inode->i_blkbits;
> + total_bytes -= page_bytes;
> }
> err = 0;
> errout:
> - fscrypt_release_ctx(ctx);
> + if (!IS_ERR_OR_NULL(ciphertext_page))
> + fscrypt_restore_control_page(ciphertext_page);
> return err;
> }
> EXPORT_SYMBOL(fscrypt_zeroout_range);
> --
> 2.19.1
>
