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ANDROID: ext4, f2fs: enable direct I/O with inline encryption

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ext4 and f2fs have traditionally not supported direct I/O on encrypted
files, since it's difficult to implement with the traditional
filesystem-layer encryption.  But when inline encryption is used
instead, it's straightforward to support direct I/O, as long as the I/O
is fully filesystem-block-aligned.  Add support for it by:

- Making the two generic direct I/O implementations in the kernel,
  __blockdev_direct_IO() and iomap_dio_rw(), set the encryption context
  on bios for inline-encrypted files.  __blockdev_direct_IO() is used by
  f2fs, and was used by ext4 in kernel v5.4 and earlier.  iomap_dio_rw()
  is used by ext4 in kernel v5.5 and later.

- Making ext4 and f2fs allow direct I/O to encrypted files (rather the
  current behavior of falling back to buffered I/O) when the file is
  using inline encryption and the I/O is fully filesystem-block-aligned.

Bug: 137270441
Change-Id: I4c8f7497eb8f829d03611d24281113d68c21d4d1
Signed-off-by: Eric Biggers <ebiggers@google.com>
This commit is contained in:
Eric Biggers 2020-01-21 09:25:59 -08:00
parent bbee78199f
commit 8f48f6657d
4 changed files with 24 additions and 5 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
fs/direct-io.c
View file

@ -23,6 +23,7 @@
#include <linux/module.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/fscrypt.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/highmem.h>
@ -430,6 +431,7 @@ dio_bio_alloc(struct dio *dio, struct dio_submit *sdio,
sector_t first_sector, int nr_vecs)
{
struct bio *bio;
struct inode *inode = dio->inode;
/*
* bio_alloc() is guaranteed to return a bio when allowed to sleep and
@ -437,6 +439,9 @@ dio_bio_alloc(struct dio *dio, struct dio_submit *sdio,
*/
bio = bio_alloc(GFP_KERNEL, nr_vecs);
fscrypt_set_bio_crypt_ctx(bio, inode,
sdio->cur_page_fs_offset >> inode->i_blkbits,
GFP_KERNEL);
bio_set_dev(bio, bdev);
bio->bi_iter.bi_sector = first_sector;
bio_set_op_attrs(bio, dio->op, dio->op_flags);

10
fs/ext4/inode.c
View file

@ -3918,10 +3918,12 @@ static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
ssize_t ret;
int rw = iov_iter_rw(iter);
#ifdef CONFIG_FS_ENCRYPTION
if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
return 0;
#endif
if (IS_ENABLED(CONFIG_FS_ENCRYPTION) && IS_ENCRYPTED(inode)) {
if (!fscrypt_inode_uses_inline_crypto(inode) ||
!IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(iter),
i_blocksize(inode)))
return 0;
}
if (fsverity_active(inode))
return 0;

8
fs/f2fs/f2fs.h
View file

@ -3735,7 +3735,13 @@ static inline bool f2fs_force_buffered_io(struct inode *inode,
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
int rw = iov_iter_rw(iter);
if (f2fs_post_read_required(inode))
if (IS_ENABLED(CONFIG_FS_ENCRYPTION) && f2fs_encrypted_file(inode)) {
if (!fscrypt_inode_uses_inline_crypto(inode) ||
!IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(iter),
F2FS_BLKSIZE))
return true;
}
if (fsverity_active(inode))
return true;
if (f2fs_is_multi_device(sbi))
return true;

6
fs/iomap.c
View file

@ -14,6 +14,7 @@
#include <linux/module.h>
#include <linux/compiler.h>
#include <linux/fs.h>
#include <linux/fscrypt.h>
#include <linux/iomap.h>
#include <linux/uaccess.h>
#include <linux/gfp.h>
@ -1580,10 +1581,13 @@ static blk_qc_t
iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
unsigned len)
{
struct inode *inode = file_inode(dio->iocb->ki_filp);
struct page *page = ZERO_PAGE(0);
struct bio *bio;
bio = bio_alloc(GFP_KERNEL, 1);
fscrypt_set_bio_crypt_ctx(bio, inode, pos >> inode->i_blkbits,
GFP_KERNEL);
bio_set_dev(bio, iomap->bdev);
bio->bi_iter.bi_sector = iomap_sector(iomap, pos);
bio->bi_private = dio;
@ -1664,6 +1668,8 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
}
bio = bio_alloc(GFP_KERNEL, nr_pages);
fscrypt_set_bio_crypt_ctx(bio, inode, pos >> inode->i_blkbits,
GFP_KERNEL);
bio_set_dev(bio, iomap->bdev);
bio->bi_iter.bi_sector = iomap_sector(iomap, pos);
bio->bi_write_hint = dio->iocb->ki_hint;