From: Jan Kara <jack@suse.cz>
To: ira.weiny@intel.com
Cc: linux-ext4@vger.kernel.org,
Andreas Dilger <adilger.kernel@dilger.ca>,
"Theodore Y. Ts'o" <tytso@mit.edu>, Jan Kara <jack@suse.cz>,
Al Viro <viro@zeniv.linux.org.uk>,
Dan Williams <dan.j.williams@intel.com>,
Dave Chinner <david@fromorbit.com>,
Christoph Hellwig <hch@lst.de>, Jeff Moyer <jmoyer@redhat.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V1 3/9] fs/ext4: Disallow encryption if inode is DAX
Date: Thu, 14 May 2020 12:23:46 +0200 [thread overview]
Message-ID: <20200514102346.GE9569@quack2.suse.cz> (raw)
In-Reply-To: <20200514065316.2500078-4-ira.weiny@intel.com>
On Wed 13-05-20 23:53:09, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
>
> Encryption and DAX are incompatible. Changing the DAX mode due to a
> change in Encryption mode is wrong without a corresponding
> address_space_operations update.
>
> Make the 2 options mutually exclusive by returning an error if DAX was
> set first.
>
> Furthermore, clarify the documentation of the exclusivity and how that
> will work.
>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Looks good to me. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>
Honza
>
> ---
> Changes:
> remove WARN_ON_ONCE
> Add documentation to the encrypt doc WRT DAX
> ---
> Documentation/filesystems/fscrypt.rst | 4 +++-
> fs/ext4/super.c | 10 +---------
> 2 files changed, 4 insertions(+), 10 deletions(-)
>
> diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst
> index aa072112cfff..1475b8d52fef 100644
> --- a/Documentation/filesystems/fscrypt.rst
> +++ b/Documentation/filesystems/fscrypt.rst
> @@ -1038,7 +1038,9 @@ astute users may notice some differences in behavior:
> - The ext4 filesystem does not support data journaling with encrypted
> regular files. It will fall back to ordered data mode instead.
>
> -- DAX (Direct Access) is not supported on encrypted files.
> +- DAX (Direct Access) is not supported on encrypted files. Attempts to enable
> + DAX on an encrypted file will fail. Mount options will _not_ enable DAX on
> + encrypted files.
>
> - The st_size of an encrypted symlink will not necessarily give the
> length of the symlink target as required by POSIX. It will actually
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index bf5fcb477f66..9873ab27e3fa 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -1320,7 +1320,7 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
> if (inode->i_ino == EXT4_ROOT_INO)
> return -EPERM;
>
> - if (WARN_ON_ONCE(IS_DAX(inode) && i_size_read(inode)))
> + if (IS_DAX(inode))
> return -EINVAL;
>
> res = ext4_convert_inline_data(inode);
> @@ -1344,10 +1344,6 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
> ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
> ext4_clear_inode_state(inode,
> EXT4_STATE_MAY_INLINE_DATA);
> - /*
> - * Update inode->i_flags - S_ENCRYPTED will be enabled,
> - * S_DAX may be disabled
> - */
> ext4_set_inode_flags(inode);
> }
> return res;
> @@ -1371,10 +1367,6 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
> ctx, len, 0);
> if (!res) {
> ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
> - /*
> - * Update inode->i_flags - S_ENCRYPTED will be enabled,
> - * S_DAX may be disabled
> - */
> ext4_set_inode_flags(inode);
> res = ext4_mark_inode_dirty(handle, inode);
> if (res)
> --
> 2.25.1
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2020-05-14 10:23 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-14 6:53 [PATCH V1 0/9] Enable ext4 support for per-file/directory DAX operations ira.weiny
2020-05-14 6:53 ` [PATCH V1 1/9] fs/ext4: Narrow scope of DAX check in setflags ira.weiny
2020-05-14 6:53 ` [PATCH V1 2/9] fs/ext4: Disallow verity if inode is DAX ira.weiny
2020-05-14 10:21 ` Jan Kara
2020-05-14 6:53 ` [PATCH V1 3/9] fs/ext4: Disallow encryption " ira.weiny
2020-05-14 10:23 ` Jan Kara [this message]
2020-05-14 6:53 ` [PATCH V1 4/9] fs/ext4: Change EXT4_MOUNT_DAX to EXT4_MOUNT_DAX_ALWAYS ira.weiny
2020-05-14 6:53 ` [PATCH V1 5/9] fs/ext4: Update ext4_should_use_dax() ira.weiny
2020-05-14 6:53 ` [PATCH V1 6/9] fs/ext4: Only change S_DAX on inode load ira.weiny
2020-05-14 6:53 ` [PATCH V1 7/9] fs/ext4: Make DAX mount option a tri-state ira.weiny
2020-05-14 11:25 ` Jan Kara
2020-05-14 14:27 ` Ira Weiny
2020-05-14 15:08 ` Darrick J. Wong
2020-05-15 3:38 ` Ira Weiny
2020-05-14 6:53 ` [PATCH V1 8/9] fs/ext4: Introduce DAX inode flag ira.weiny
2020-05-14 11:06 ` Jan Kara
2020-05-14 6:53 ` [PATCH V1 9/9] Documentation/dax: Update DAX enablement for ext4 ira.weiny
2020-05-14 11:15 ` Jan Kara
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