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ext4: add inline encryption support

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Wire up ext4 to support inline encryption via the helper functions which
fs/crypto/ now provides.  This includes:

- Adding a mount option 'inlinecrypt' which enables inline encryption
  on encrypted files where it can be used.

- Setting the bio_crypt_ctx on bios that will be submitted to an
  inline-encrypted file.

  Note: submit_bh_wbc() in fs/buffer.c also needed to be patched for
  this part, since ext4 sometimes uses ll_rw_block() on file data.

- Not adding logically discontiguous data to bios that will be submitted
  to an inline-encrypted file.

- Not doing filesystem-layer crypto on inline-encrypted files.

Co-developed-by: Satya Tangirala <satyat@google.com>
Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20200702015607.1215430-5-satyat@google.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
This commit is contained in:
Eric Biggers
2020-07-02 01:56:07 +00:00
parent 27aacd28ea
commit 4f74d15fe4
6 changed files with 37 additions and 10 deletions
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11
fs/ext4/readpage.c
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@@ -195,7 +195,7 @@ static void ext4_set_bio_post_read_ctx(struct bio *bio,
{
unsigned int post_read_steps = 0;
if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
if (fscrypt_inode_uses_fs_layer_crypto(inode))
post_read_steps |= 1 << STEP_DECRYPT;
if (ext4_need_verity(inode, first_idx))
@@ -230,6 +230,7 @@ int ext4_mpage_readpages(struct inode *inode,
const unsigned blkbits = inode->i_blkbits;
const unsigned blocks_per_page = PAGE_SIZE >> blkbits;
const unsigned blocksize = 1 << blkbits;
sector_t next_block;
sector_t block_in_file;
sector_t last_block;
sector_t last_block_in_file;
@@ -258,7 +259,8 @@ int ext4_mpage_readpages(struct inode *inode,
if (page_has_buffers(page))
goto confused;
block_in_file = (sector_t)page->index << (PAGE_SHIFT - blkbits);
block_in_file = next_block =
(sector_t)page->index << (PAGE_SHIFT - blkbits);
last_block = block_in_file + nr_pages * blocks_per_page;
last_block_in_file = (ext4_readpage_limit(inode) +
blocksize - 1) >> blkbits;
@@ -358,7 +360,8 @@ int ext4_mpage_readpages(struct inode *inode,
* This page will go to BIO. Do we need to send this
* BIO off first?
*/
if (bio && (last_block_in_bio != blocks[0] - 1)) {
if (bio && (last_block_in_bio != blocks[0] - 1 ||
!fscrypt_mergeable_bio(bio, inode, next_block))) {
submit_and_realloc:
submit_bio(bio);
bio = NULL;
@@ -370,6 +373,8 @@ int ext4_mpage_readpages(struct inode *inode,
*/
bio = bio_alloc(GFP_KERNEL,
min_t(int, nr_pages, BIO_MAX_PAGES));
fscrypt_set_bio_crypt_ctx(bio, inode, next_block,
GFP_KERNEL);
ext4_set_bio_post_read_ctx(bio, inode, page->index);
bio_set_dev(bio, bdev);
bio->bi_iter.bi_sector = blocks[0] << (blkbits - 9);