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FROMLIST: ext4: support direct I/O with fscrypt using blk-crypto

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Wire up ext4 with fscrypt direct I/O support. Direct I/O with fscrypt is
only supported through blk-crypto (i.e. CONFIG_BLK_INLINE_ENCRYPTION must
have been enabled, the 'inlinecrypt' mount option must have been specified,
and either hardware inline encryption support must be present or
CONFIG_BLK_INLINE_ENCYRPTION_FALLBACK must have been enabled). Further,
direct I/O on encrypted files is only supported when I/O is aligned
to the filesystem block size (which is *not* necessarily the same as the
block device's block size).

fscrypt_limit_io_blocks() is called before setting up the iomap to ensure
that the blocks of each bio that iomap will submit will have contiguous
DUNs. Note that fscrypt_limit_io_blocks() is normally a no-op, as normally
the DUNs simply increment along with the logical blocks. But it's needed
to handle an edge case in one of the fscrypt IV generation methods.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Co-developed-by: Satya Tangirala <satyat@google.com>
Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>

Bug: 162255927
Link: https://lore.kernel.org/r/20200724184501.1651378-5-satyat@google.com
Change-Id: Ia3d869cefabdff070f4e77c46190351f6cb5d74c
Signed-off-by: Eric Biggers <ebiggers@google.com>
This commit is contained in:
Eric Biggers
2020-07-24 18:44:58 +00:00
committed by Greg Kroah-Hartman
parent 89d89a9580
commit 328a492ae5
2 changed files with 14 additions and 4 deletions
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10
fs/ext4/file.c
View File

@@ -36,9 +36,11 @@
#include "acl.h"
#include "truncate.h"
static bool ext4_dio_supported(struct inode *inode)
static bool ext4_dio_supported(struct kiocb *iocb, struct iov_iter *iter)
{
if (IS_ENABLED(CONFIG_FS_ENCRYPTION) && IS_ENCRYPTED(inode))
struct inode *inode = file_inode(iocb->ki_filp);
if (!fscrypt_dio_supported(iocb, iter))
return false;
if (fsverity_active(inode))
return false;
@@ -61,7 +63,7 @@ static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
inode_lock_shared(inode);
}
if (!ext4_dio_supported(inode)) {
if (!ext4_dio_supported(iocb, to)) {
inode_unlock_shared(inode);
/*
* Fallback to buffered I/O if the operation being performed on
@@ -494,7 +496,7 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
}
/* Fallback to buffered I/O if the inode does not support direct I/O. */
if (!ext4_dio_supported(inode)) {
if (!ext4_dio_supported(iocb, from)) {
if (ilock_shared)
inode_unlock_shared(inode);
else

8
fs/ext4/inode.c
View File

@@ -3506,6 +3506,14 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
if (ret < 0)
return ret;
out:
/*
* When inline encryption is enabled, sometimes I/O to an encrypted file
* has to be broken up to guarantee DUN contiguity. Handle this by
* limiting the length of the mapping returned.
*/
map.m_len = fscrypt_limit_io_blocks(inode, map.m_lblk, map.m_len);
ext4_set_iomap(inode, iomap, &map, offset, length);
return 0;