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;
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);
ciphertext_page = fscrypt_alloc_bounce_page(ctx, GFP_NOWAIT);
if (IS_ERR(ciphertext_page)) {
err = PTR_ERR(ciphertext_page);
goto errout;
}
while (len--) {
err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk,
ZERO_PAGE(0), ciphertext_page,
PAGE_SIZE, 0, GFP_NOFS);
if (err)
goto errout;
bio = bio_alloc(GFP_NOWAIT, 1);
if (!bio) {
err = -ENOMEM;
goto errout;
}
bio_set_dev(bio, inode->i_sb->s_bdev);
bio->bi_iter.bi_sector =
pblk << (inode->i_sb->s_blocksize_bits - 9);
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) {
/* should never happen! */
WARN_ON(1);
bio_put(bio);
err = -EIO;
goto errout;
}
err = submit_bio_wait(bio);
if (err == 0 && bio->bi_status)
err = -EIO;
bio_put(bio);
if (err)
goto errout;
lblk++;
pblk++;
}
err = 0;
errout:
fscrypt_release_ctx(ctx);
return err;
}
/**
* fscypt_encrypt_page() - Encrypts a page
* @inode: The inode for which the encryption should take place
* @page: The page to encrypt. Must be locked for bounce-page
* encryption.
* @len: Length of data to encrypt in @page and encrypted
* data in returned page.
* @offs: Offset of data within @page and returned
* page holding encrypted data.
* @lblk_num: Logical block number. This must be unique for multiple
* calls with same inode, except when overwriting
* previously written data.
* @gfp_flags: The gfp flag for memory allocation
*
* Encrypts @page using the ctx encryption context. Performs encryption
* either in-place or into a newly allocated bounce page.
* Called on the page write path.
*
* Bounce page allocation is the default.
* In this case, the contents of @page are encrypted and stored in an
* allocated bounce page. @page has to be locked and the caller must call
* fscrypt_restore_control_page() on the returned ciphertext page to
* release the bounce buffer and the encryption context.
*
* In-place encryption is used by setting the FS_CFLG_OWN_PAGES flag in
* fscrypt_operations. Here, the input-page is returned with its content
* encrypted.
*
* Return: A page with the encrypted content on success. Else, an
* error value or NULL.
*/
struct page *fscrypt_encrypt_page(const struct inode *inode,
struct page *page,
unsigned int len,
unsigned int offs,
u64 lblk_num, gfp_t gfp_flags)
{
struct fscrypt_ctx *ctx;
struct page *ciphertext_page = page;
int err;
BUG_ON(len % FS_CRYPTO_BLOCK_SIZE != 0);
if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) {
/* with inplace-encryption we just encrypt the page */
err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, page,
ciphertext_page, len, offs,
gfp_flags);
if (err)
return ERR_PTR(err);
return ciphertext_page;
}
BUG_ON(!PageLocked(page));
ctx = fscrypt_get_ctx(gfp_flags);
if (IS_ERR(ctx))
return ERR_CAST(ctx);
/* The encryption operation will require a bounce page. */
ciphertext_page = fscrypt_alloc_bounce_page(ctx, gfp_flags);
if (IS_ERR(ciphertext_page))
goto errout;
ctx->w.control_page = page;
err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num,
page, ciphertext_page, len, offs,
gfp_flags);
if (err) {
ciphertext_page = ERR_PTR(err);
goto errout;
}
SetPagePrivate(ciphertext_page);
set_page_private(ciphertext_page, (unsigned long)ctx);
lock_page(ciphertext_page);
return ciphertext_page;
errout:
fscrypt_release_ctx(ctx);
return ciphertext_page;
}
