/**
* ext4_encrypt() - Encrypts a page
* @inode: The inode for which the encryption should take place
* @plaintext_page: The page to encrypt. Must be locked.
*
* Allocates a ciphertext page and encrypts plaintext_page into it using the ctx
* encryption context.
*
* Called on the page write path. The caller must call
* ext4_restore_control_page() on the returned ciphertext page to
* release the bounce buffer and the encryption context.
*
* Return: An allocated page with the encrypted content on success. Else, an
* error value or NULL.
*/
struct page *ext4_encrypt(struct inode *inode,
struct page *plaintext_page)
{
struct ext4_crypto_ctx *ctx;
struct page *ciphertext_page = NULL;
int err;
BUG_ON(!PageLocked(plaintext_page));
ctx = ext4_get_crypto_ctx(inode);
if (IS_ERR(ctx))
return (struct page *) ctx;
/* The encryption operation will require a bounce page. */
ciphertext_page = alloc_bounce_page(ctx);
if (IS_ERR(ciphertext_page))
goto errout;
ctx->w.control_page = plaintext_page;
err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, plaintext_page->index,
plaintext_page, ciphertext_page);
if (err) {
ciphertext_page = ERR_PTR(err);
errout:
ext4_release_crypto_ctx(ctx);
return ciphertext_page;
}
SetPagePrivate(ciphertext_page);
set_page_private(ciphertext_page, (unsigned long)ctx);
lock_page(ciphertext_page);
return ciphertext_page;
}
/**
* ext4_decrypt() - Decrypts a page in-place
* @ctx: The encryption context.
* @page: The page to decrypt. Must be locked.
*
* Decrypts page in-place using the ctx encryption context.
*
* Called from the read completion callback.
*
* Return: Zero on success, non-zero otherwise.
*/
int ext4_decrypt(struct ext4_crypto_ctx *ctx, struct page *page)
{
BUG_ON(!PageLocked(page));
return ext4_page_crypto(ctx, page->mapping->host,
EXT4_DECRYPT, page->index, page, page);
}
int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex)
{
struct ext4_crypto_ctx *ctx;
struct page *ciphertext_page = NULL;
struct bio *bio;
ext4_lblk_t lblk = ex->ee_block;
ext4_fsblk_t pblk = ext4_ext_pblock(ex);
unsigned int len = ext4_ext_get_actual_len(ex);
int err = 0;
BUG_ON(inode->i_sb->s_blocksize != PAGE_CACHE_SIZE);
ctx = ext4_get_crypto_ctx(inode);
if (IS_ERR(ctx))
return PTR_ERR(ctx);
ciphertext_page = alloc_bounce_page(ctx);
if (IS_ERR(ciphertext_page)) {
err = PTR_ERR(ciphertext_page);
goto errout;
}
while (len--) {
err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, lblk,
ZERO_PAGE(0), ciphertext_page);
if (err)
goto errout;
bio = bio_alloc(GFP_KERNEL, 1);
if (!bio) {
err = -ENOMEM;
goto errout;
}
bio->bi_bdev = inode->i_sb->s_bdev;
bio->bi_sector = pblk;
err = bio_add_page(bio, ciphertext_page,
inode->i_sb->s_blocksize, 0);
if (err) {
bio_put(bio);
goto errout;
}
err = submit_bio_wait(WRITE, bio);
bio_put(bio);
if (err)
goto errout;
}
err = 0;
errout:
ext4_release_crypto_ctx(ctx);
return err;
}
int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex)
{
struct ext4_crypto_ctx *ctx;
struct page *ciphertext_page = NULL;
struct bio *bio;
ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
ext4_fsblk_t pblk = ext4_ext_pblock(ex);
unsigned int len = ext4_ext_get_actual_len(ex);
int ret, err = 0;
#if 0
ext4_msg(inode->i_sb, KERN_CRIT,
"ext4_encrypted_zeroout ino %lu lblk %u len %u",
(unsigned long) inode->i_ino, lblk, len);
#endif
BUG_ON(inode->i_sb->s_blocksize != PAGE_CACHE_SIZE);
ctx = ext4_get_crypto_ctx(inode);
if (IS_ERR(ctx))
return PTR_ERR(ctx);
ciphertext_page = alloc_bounce_page(ctx);
if (IS_ERR(ciphertext_page)) {
err = PTR_ERR(ciphertext_page);
goto errout;
}
while (len--) {
err = ext4_page_crypto(inode, EXT4_ENCRYPT, lblk,
ZERO_PAGE(0), ciphertext_page);
if (err)
goto errout;
bio = bio_alloc(GFP_KERNEL, 1);
if (!bio) {
err = -ENOMEM;
goto errout;
}
bio->bi_bdev = inode->i_sb->s_bdev;
bio->bi_iter.bi_sector =
pblk << (inode->i_sb->s_blocksize_bits - 9);
ret = bio_add_page(bio, ciphertext_page,
inode->i_sb->s_blocksize, 0);
if (ret != inode->i_sb->s_blocksize) {
/* should never happen! */
ext4_msg(inode->i_sb, KERN_ERR,
"bio_add_page failed: %d", ret);
WARN_ON(1);
bio_put(bio);
err = -EIO;
goto errout;
}
err = submit_bio_wait(WRITE, bio);
if ((err == 0) && bio->bi_error)
err = -EIO;
bio_put(bio);
if (err)
goto errout;
lblk++; pblk++;
}
err = 0;
errout:
ext4_release_crypto_ctx(ctx);
return err;
}