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 8/9] fs/ext4: Introduce DAX inode flag
Date: Wed, 13 May 2020 16:47:06 +0200 [thread overview]
Message-ID: <20200513144706.GH27709@quack2.suse.cz> (raw)
In-Reply-To: <20200513054324.2138483-9-ira.weiny@intel.com>
On Tue 12-05-20 22:43:23, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
>
> Add a flag to preserve FS_XFLAG_DAX in the ext4 inode.
>
> Set the flag to be user visible and changeable. Set the flag to be
> inherited. Allow applications to change the flag at any time.
>
> Finally, on regular files, flag the inode to not be cached to facilitate
> changing S_DAX on the next creation of the inode.
>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
>
> ---
> Change from RFC:
> use new d_mark_dontcache()
> Allow caching if ALWAYS/NEVER is set
> Rebased to latest Linus master
> Change flag to unused 0x01000000
> update ext4_should_enable_dax()
> ---
> fs/ext4/ext4.h | 13 +++++++++----
> fs/ext4/inode.c | 4 +++-
> fs/ext4/ioctl.c | 25 ++++++++++++++++++++++++-
> 3 files changed, 36 insertions(+), 6 deletions(-)
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 01d1de838896..715f8f2029b2 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -415,13 +415,16 @@ struct flex_groups {
> #define EXT4_VERITY_FL 0x00100000 /* Verity protected inode */
> #define EXT4_EA_INODE_FL 0x00200000 /* Inode used for large EA */
> /* 0x00400000 was formerly EXT4_EOFBLOCKS_FL */
> +
> +#define EXT4_DAX_FL 0x01000000 /* Inode is DAX */
> +
> #define EXT4_INLINE_DATA_FL 0x10000000 /* Inode has inline data. */
> #define EXT4_PROJINHERIT_FL 0x20000000 /* Create with parents projid */
> #define EXT4_CASEFOLD_FL 0x40000000 /* Casefolded file */
> #define EXT4_RESERVED_FL 0x80000000 /* reserved for ext4 lib */
>
> -#define EXT4_FL_USER_VISIBLE 0x705BDFFF /* User visible flags */
> -#define EXT4_FL_USER_MODIFIABLE 0x604BC0FF /* User modifiable flags */
> +#define EXT4_FL_USER_VISIBLE 0x715BDFFF /* User visible flags */
> +#define EXT4_FL_USER_MODIFIABLE 0x614BC0FF /* User modifiable flags */
Hum, I think this was already mentioned but there are also definitions in
include/uapi/linux/fs.h which should be kept in sync... Also if DAX flag
gets modified through FS_IOC_SETFLAGS, we should call ext4_doncache() as
well, shouldn't we?
> @@ -802,6 +807,21 @@ static int ext4_ioctl_get_es_cache(struct file *filp, unsigned long arg)
> return error;
> }
>
> +static void ext4_dax_dontcache(struct inode *inode, unsigned int flags)
> +{
> + struct ext4_inode_info *ei = EXT4_I(inode);
> +
> + if (S_ISDIR(inode->i_mode))
> + return;
> +
> + if (test_opt2(inode->i_sb, DAX_NEVER) ||
> + test_opt(inode->i_sb, DAX_ALWAYS))
> + return;
> +
> + if (((ei->i_flags ^ flags) & EXT4_DAX_FL) == EXT4_DAX_FL)
> + d_mark_dontcache(inode);
> +}
> +
> long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> {
> struct inode *inode = file_inode(filp);
> @@ -1267,6 +1287,9 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> return err;
>
> inode_lock(inode);
> +
> + ext4_dax_dontcache(inode, flags);
> +
I don't think we should set dontcache flag when setting of DAX flag fails -
it could event be a security issue). So I think you'll have to check
whether DAX flag is being changed, call vfs_ioc_fssetxattr_check(), and
only if it succeeded and DAX flags was changing call ext4_dax_dontcache().
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2020-05-13 15:05 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-13 5:43 [PATCH 0/9] Enable ext4 support for per-file/directory DAX operations ira.weiny
2020-05-13 5:43 ` [PATCH 1/9] fs/ext4: Narrow scope of DAX check in setflags ira.weiny
2020-05-13 5:43 ` [PATCH 2/9] fs/ext4: Disallow verity if inode is DAX ira.weiny
2020-05-16 1:49 ` Eric Biggers
2020-05-18 5:32 ` Ira Weiny
2020-05-13 5:43 ` [PATCH 3/9] fs/ext4: Disallow encryption " ira.weiny
2020-05-16 2:02 ` Eric Biggers
2020-05-18 5:03 ` Ira Weiny
2020-05-18 16:24 ` Eric Biggers
2020-05-18 19:23 ` Ira Weiny
2020-05-18 19:44 ` Eric Biggers
2020-05-20 2:02 ` Ira Weiny
2020-05-20 13:11 ` Jan Kara
2020-05-13 5:43 ` [PATCH 4/9] fs/ext4: Change EXT4_MOUNT_DAX to EXT4_MOUNT_DAX_ALWAYS ira.weiny
2020-05-13 11:25 ` Jan Kara
2020-05-13 5:43 ` [PATCH 5/9] fs/ext4: Update ext4_should_use_dax() ira.weiny
2020-05-13 11:30 ` Jan Kara
2020-05-13 5:43 ` [PATCH 6/9] fs/ext4: Only change S_DAX on inode load ira.weiny
2020-05-13 11:33 ` Jan Kara
2020-05-13 5:43 ` [PATCH 7/9] fs/ext4: Make DAX mount option a tri-state ira.weiny
2020-05-13 14:35 ` Jan Kara
2020-05-13 18:17 ` Darrick J. Wong
2020-05-13 19:53 ` Ira Weiny
2020-05-13 5:43 ` [PATCH 8/9] fs/ext4: Introduce DAX inode flag ira.weiny
2020-05-13 6:57 ` kbuild test robot
2020-05-13 14:47 ` Jan Kara [this message]
2020-05-13 21:41 ` Ira Weiny
2020-05-14 6:43 ` Jan Kara
2020-05-14 6:55 ` Ira Weiny
2020-05-13 5:43 ` [PATCH 9/9] Documentation/dax: Update DAX enablement for ext4 ira.weiny
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