From: Satya Tangirala <satyat@google.com> To: "Theodore Y . Ts'o" <tytso@mit.edu>, Jaegeuk Kim <jaegeuk@kernel.org>, Eric Biggers <ebiggers@kernel.org>, Chao Yu <chao@kernel.org>, Jens Axboe <axboe@kernel.dk>, "Darrick J . Wong" <darrick.wong@oracle.com> Cc: linux-kernel@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, linux-block@vger.kernel.org, linux-ext4@vger.kernel.org, Satya Tangirala <satyat@google.com>, Eric Biggers <ebiggers@google.com> Subject: [PATCH v9 9/9] fscrypt: update documentation for direct I/O support Date: Fri, 4 Jun 2021 21:09:08 +0000 [thread overview] Message-ID: <20210604210908.2105870-10-satyat@google.com> (raw) In-Reply-To: <20210604210908.2105870-1-satyat@google.com> Update fscrypt documentation to reflect the addition of direct I/O support and document the necessary conditions for direct I/O on encrypted files. Signed-off-by: Satya Tangirala <satyat@google.com> Reviewed-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> --- Documentation/filesystems/fscrypt.rst | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst index 44b67ebd6e40..c0c1747fa2fb 100644 --- a/Documentation/filesystems/fscrypt.rst +++ b/Documentation/filesystems/fscrypt.rst @@ -1047,8 +1047,10 @@ astute users may notice some differences in behavior: may be used to overwrite the source files but isn't guaranteed to be effective on all filesystems and storage devices. -- Direct I/O is not supported on encrypted files. Attempts to use - direct I/O on such files will fall back to buffered I/O. +- Direct I/O is supported on encrypted files only under some + circumstances (see `Direct I/O support`_ for details). When these + circumstances are not met, attempts to use direct I/O on encrypted + files will fall back to buffered I/O. - The fallocate operations FALLOC_FL_COLLAPSE_RANGE and FALLOC_FL_INSERT_RANGE are not supported on encrypted files and will @@ -1121,6 +1123,21 @@ It is not currently possible to backup and restore encrypted files without the encryption key. This would require special APIs which have not yet been implemented. +Direct I/O support +================== + +Direct I/O on encrypted files is supported through blk-crypto. In +particular, this means the kernel must have CONFIG_BLK_INLINE_ENCRYPTION +enabled, the filesystem must have had the 'inlinecrypt' mount option +specified, and either hardware inline encryption must be present, or +CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK must have been enabled. Further, +the starting position in the file and the length of any I/O must be aligned +to the filesystem block size (*not* necessarily the same as the block +device's block size). If any of these conditions isn't met, attempts to do +direct I/O on an encrypted file will fall back to buffered I/O. However, +there aren't any additional requirements on user buffer alignment (apart +from those already present when using direct I/O on unencrypted files). + Encryption policy enforcement ============================= -- 2.32.0.rc1.229.g3e70b5a671-goog
WARNING: multiple messages have this Message-ID (diff)
From: Satya Tangirala via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net> To: "Theodore Y . Ts'o" <tytso@mit.edu>, Jaegeuk Kim <jaegeuk@kernel.org>, Eric Biggers <ebiggers@kernel.org>, Chao Yu <chao@kernel.org>, Jens Axboe <axboe@kernel.dk>, "Darrick J . Wong" <darrick.wong@oracle.com> Cc: linux-block@vger.kernel.org, Eric Biggers <ebiggers@google.com>, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, linux-fscrypt@vger.kernel.org, Satya Tangirala <satyat@google.com>, linux-ext4@vger.kernel.org Subject: [f2fs-dev] [PATCH v9 9/9] fscrypt: update documentation for direct I/O support Date: Fri, 4 Jun 2021 21:09:08 +0000 [thread overview] Message-ID: <20210604210908.2105870-10-satyat@google.com> (raw) In-Reply-To: <20210604210908.2105870-1-satyat@google.com> Update fscrypt documentation to reflect the addition of direct I/O support and document the necessary conditions for direct I/O on encrypted files. Signed-off-by: Satya Tangirala <satyat@google.com> Reviewed-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> --- Documentation/filesystems/fscrypt.rst | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst index 44b67ebd6e40..c0c1747fa2fb 100644 --- a/Documentation/filesystems/fscrypt.rst +++ b/Documentation/filesystems/fscrypt.rst @@ -1047,8 +1047,10 @@ astute users may notice some differences in behavior: may be used to overwrite the source files but isn't guaranteed to be effective on all filesystems and storage devices. -- Direct I/O is not supported on encrypted files. Attempts to use - direct I/O on such files will fall back to buffered I/O. +- Direct I/O is supported on encrypted files only under some + circumstances (see `Direct I/O support`_ for details). When these + circumstances are not met, attempts to use direct I/O on encrypted + files will fall back to buffered I/O. - The fallocate operations FALLOC_FL_COLLAPSE_RANGE and FALLOC_FL_INSERT_RANGE are not supported on encrypted files and will @@ -1121,6 +1123,21 @@ It is not currently possible to backup and restore encrypted files without the encryption key. This would require special APIs which have not yet been implemented. +Direct I/O support +================== + +Direct I/O on encrypted files is supported through blk-crypto. In +particular, this means the kernel must have CONFIG_BLK_INLINE_ENCRYPTION +enabled, the filesystem must have had the 'inlinecrypt' mount option +specified, and either hardware inline encryption must be present, or +CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK must have been enabled. Further, +the starting position in the file and the length of any I/O must be aligned +to the filesystem block size (*not* necessarily the same as the block +device's block size). If any of these conditions isn't met, attempts to do +direct I/O on an encrypted file will fall back to buffered I/O. However, +there aren't any additional requirements on user buffer alignment (apart +from those already present when using direct I/O on unencrypted files). + Encryption policy enforcement ============================= -- 2.32.0.rc1.229.g3e70b5a671-goog _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
next prev parent reply other threads:[~2021-06-04 21:10 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-06-04 21:08 [PATCH v9 0/9] add support for direct I/O with fscrypt using blk-crypto Satya Tangirala 2021-06-04 21:08 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2021-06-04 21:09 ` [PATCH v9 1/9] block: blk-crypto-fallback: handle data unit split across multiple bvecs Satya Tangirala 2021-06-04 21:09 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2021-06-04 21:09 ` [PATCH v9 2/9] block: blk-crypto: relax alignment requirements for bvecs in bios Satya Tangirala 2021-06-04 21:09 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2021-06-04 21:09 ` [PATCH v9 3/9] fscrypt: add functions for direct I/O support Satya Tangirala 2021-06-04 21:09 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2021-07-23 20:42 ` Eric Biggers 2021-07-23 20:42 ` [f2fs-dev] " Eric Biggers 2021-06-04 21:09 ` [PATCH v9 4/9] direct-io: add support for fscrypt using blk-crypto Satya Tangirala 2021-06-04 21:09 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2021-06-04 21:09 ` [PATCH v9 5/9] block: Make bio_iov_iter_get_pages() respect bio_required_sector_alignment() Satya Tangirala 2021-06-04 21:09 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2021-06-04 22:51 ` kernel test robot 2021-06-04 22:51 ` kernel test robot 2021-06-05 2:55 ` kernel test robot 2021-06-05 2:55 ` kernel test robot 2021-07-23 21:33 ` Eric Biggers 2021-07-23 21:33 ` [f2fs-dev] " Eric Biggers 2021-07-24 7:19 ` Christoph Hellwig 2021-07-24 7:19 ` [f2fs-dev] " Christoph Hellwig 2021-06-04 21:09 ` [PATCH v9 6/9] iomap: support direct I/O with fscrypt using blk-crypto Satya Tangirala 2021-06-04 21:09 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2021-07-22 19:04 ` Darrick J. Wong 2021-07-22 19:04 ` [f2fs-dev] " Darrick J. Wong 2021-06-04 21:09 ` [PATCH v9 7/9] ext4: " Satya Tangirala 2021-06-04 21:09 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2021-06-04 21:09 ` [PATCH v9 8/9] f2fs: " Satya Tangirala 2021-06-04 21:09 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2021-06-04 21:09 ` Satya Tangirala [this message] 2021-06-04 21:09 ` [f2fs-dev] [PATCH v9 9/9] fscrypt: update documentation for direct I/O support Satya Tangirala via Linux-f2fs-devel [not found] ` <CAF2Aj3h-Gt3bOxH4wXB7aeQ3jVzR3TEqd3uLsh4T9Q=e6W6iqQ@mail.gmail.com> 2021-07-22 14:48 ` [PATCH v9 0/9] add support for direct I/O with fscrypt using blk-crypto Eric Biggers 2021-07-22 14:48 ` [f2fs-dev] " Eric Biggers 2021-08-04 8:26 ` Lee Jones 2021-08-04 8:26 ` [f2fs-dev] " Lee Jones
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