Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 179e66be authored by Eric Biggers's avatar Eric Biggers Committed by Jaegeuk Kim
Browse files

fscrypt: handle blocksize < PAGE_SIZE in fscrypt_zeroout_range() 



Adjust fscrypt_zeroout_range() to encrypt a block at a time rather than
a page at a time, so that it works when blocksize < PAGE_SIZE.

This isn't optimized for performance, but then again this function
already wasn't optimized for performance.  As a future optimization, we
could submit much larger bios here.

This is in preparation for allowing encryption on ext4 filesystems with
blocksize != PAGE_SIZE.

This is based on work by Chandan Rajendra.

Reviewed-by: default avatarChandan Rajendra <chandan@linux.ibm.com>
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
parent fd0e18f3

fs/crypto/bio.c

+6 −9
Original line number Diff line number Diff line
@@ -72,12 +72,12 @@ EXPORT_SYMBOL(fscrypt_enqueue_decrypt_bio); 
int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,

				sector_t pblk, unsigned int len)

{

	const unsigned int blockbits = inode->i_blkbits;

	const unsigned int blocksize = 1 << blockbits;

	struct page *ciphertext_page;

	struct bio *bio;

	int ret, err = 0;



	BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE);



	ciphertext_page = fscrypt_alloc_bounce_page(GFP_NOWAIT);

	if (!ciphertext_page)

		return -ENOMEM;
@@ -85,7 +85,7 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, 
	while (len--) {

		err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk,

					  ZERO_PAGE(0), ciphertext_page,

					  PAGE_SIZE, 0, GFP_NOFS);

					  blocksize, 0, GFP_NOFS);

		if (err)

			goto errout;
@@ -95,14 +95,11 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, 
			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->bi_iter.bi_sector = pblk << (blockbits - 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) {

		ret = bio_add_page(bio, ciphertext_page, blocksize, 0);

		if (WARN_ON(ret != blocksize)) {

			/* should never happen! */

			WARN_ON(1);

			bio_put(bio);

			err = -EIO;

			goto errout;