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From: Satya Tangirala <satyat@google.com>
To: linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net,
	linux-ext4@vger.kernel.org
Cc: linux-xfs@vger.kernel.org, Eric Biggers <ebiggers@google.com>,
	Satya Tangirala <satyat@google.com>,
	Jaegeuk Kim <jaegeuk@kernel.org>
Subject: [PATCH v6 4/7] ext4: support direct I/O with fscrypt using blk-crypto
Date: Fri, 24 Jul 2020 18:44:58 +0000
Message-ID: <20200724184501.1651378-5-satyat@google.com> (raw)
In-Reply-To: <20200724184501.1651378-1-satyat@google.com>

From: Eric Biggers <ebiggers@google.com>

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>
---
 fs/ext4/file.c  | 10 ++++++----
 fs/ext4/inode.c |  7 +++++++
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 2a01e31a032c..d534f72675d9 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -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
@@ -490,7 +492,7 @@ 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
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 44bad4bb8831..6725116ea348 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3445,6 +3445,13 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 	if (ret < 0)
 		return ret;
 
+	/*
+	 * 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;
-- 
2.28.0.rc0.142.g3c755180ce-goog


  parent reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-24 18:44 [PATCH v6 0/7] add support for " Satya Tangirala
2020-07-24 18:44 ` [PATCH v6 1/7] fscrypt: Add functions for direct I/O support Satya Tangirala
2020-07-25  0:14   ` Dave Chinner
2020-07-26  2:49     ` [f2fs-dev] " Eric Biggers
2020-07-27  0:58       ` Dave Chinner
2020-07-27  2:59         ` Eric Biggers
2020-07-27  4:47           ` Dave Chinner
2020-07-24 18:44 ` [PATCH v6 2/7] direct-io: add support for fscrypt using blk-crypto Satya Tangirala
2020-07-24 18:44 ` [PATCH v6 3/7] iomap: support direct I/O with " Satya Tangirala
2020-07-24 18:44 ` Satya Tangirala [this message]
2020-07-24 18:44 ` [PATCH v6 5/7] f2fs: " Satya Tangirala
2020-07-24 18:45 ` [PATCH v6 6/7] fscrypt: document inline encryption support Satya Tangirala
2020-07-27 16:43   ` Eric Biggers
2020-07-24 18:45 ` [PATCH v6 7/7] fscrypt: update documentation for direct I/O support Satya Tangirala

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