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From: Casey Schaufler <casey@schaufler-ca.com>
To: David Howells <dhowells@redhat.com>, arnd@arndb.de
Cc: linux-afs@vger.kernel.org, linux-nfs@vger.kernel.org,
	linux-cifs@vger.kernel.org, samba-technical@lists.samba.org,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-ext4@vger.kernel.org
Subject: Re: [RFC][PATCH 00/12] Enhanced file stat system call
Date: Fri, 20 Nov 2015 08:50:22 -0800	[thread overview]
Message-ID: <564F4F4E.8060603@schaufler-ca.com> (raw)
In-Reply-To: <20151120145422.18930.72662.stgit@warthog.procyon.org.uk>



On 11/20/2015 6:54 AM, David Howells wrote:
> Implement new system calls to provide enhanced file stats and enhanced
> filesystem stats.  The patches can be found here:
>
> 	http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git/log/?h=xstat
>
>
> ===========
> DESCRIPTION
> ===========
>
> The third patch provides this new system call:
>
> 	long ret = statx(int dfd,
> 			 const char *filename,
> 			 unsigned atflag,
> 			 unsigned mask,
> 			 struct statx *buffer);
>
> This is an enhanced file stat function that provides a number of useful
> features, in summary:
>
>   (1) More information: creation time, data version number,
>       flags/attributes.  A subset of these is available through a number of
>       filesystems (such as CIFS, NFS, AFS, Ext4 and BTRFS).
>
>   (2) Lightweight stat (AT_NO_ATTR_SYNC): Ask for just those details of
>       interest, and allow a network fs to approximate anything not of
>       interest, without going to the server.
>
>   (3) Heavyweight stat (AT_FORCE_ATTR_SYNC): Force a network fs to flush
>       buffers and go to the server, even if it thinks its cached attributes
>       are up to date.
>
>   (4) Allow the filesystem to indicate what it can/cannot provide: A
>       filesystem can now say it doesn't support a standard stat feature if
>       that isn't available.
>
>   (5) Make the fields a consistent size on all arches, and make them large.
>
>   (6) Can be extended by using more request flags and using up the padding
>       space in the statx struct.

How about relevant xattrs? SELinux context, ACL, that sort of thing.
The fact that these are optional should be taken care of by (4).

>
> Note that no lstat() equivalent is required as that can be implemented
> through statx() with atflag == 0.  There is also no fstat() equivalent as
> that can be implemented through statx() with filename == NULL and the
> relevant fd passed as dfd.
>
>
> The seventh patch provides another new system call:
>
> 	long ret = fsinfo(int dfd,
> 			  const char *filename,
> 			  unsigned atflag,
> 			  unsigned request,
> 			  void *buffer);
>
> This is an enhanced filesystem stat and information retrieval function that
> provides more information, in summary:
>
>   (1) All the information provided by statfs() and more.  The fields are
>       made large.
>
>   (2) Provides information about timestamp range and resolution to
>       complement statx().
>
>   (3) Provides information about IOC flags supported in statx()'s return.
>
>   (4) Provides volume binary IDs and UUIDs.
>
>   (5) Provides the filesystem name according to the kernel as a string
>       (eg. "ext4" or "nfs3") in addition to the magic number.
>
>   (6) Provides information obtained from network filesystems, such as volume
>       and domain names.
>
>   (7) Has lots of spare space that can be used for future extenstions and a
>       bit mask indicating what was provided.
>
> Note that I've added a 'request' identifier.  This is to select the set of
> data to be returned.  The idea is that 'buffer' points to a fixed-size
> struct selected by request.  Currently only 0 is available and this refers
> to 'struct fsinfo'.  However, I could split up the buffer into say 3:
>
>   (0) statfs-type information
>
>   (1) Timestamp and IOC flags info.
>
>   (2) Network fs strings.
>
> However, some of this might be better retrieved through getxattr().
>
>
> =======
> TESTING
> =======
>
> Test programs are added into samples/statx/ by the appropriate patches.
>
> David
> ---
> David Howells (12):
>        Ext4: Fix extended timestamp encoding and decoding
>        statx: Provide IOC flags for Windows fs attributes
>        statx: Add a system call to make enhanced file info available
>        statx: AFS: Return enhanced file attributes
>        statx: Ext4: Return enhanced file attributes
>        statx: NFS: Return enhanced file attributes
>        statx: CIFS: Return enhanced attributes
>        fsinfo: Add a system call to make enhanced filesystem info available
>        fsinfo: Ext4: Return information through the filesystem info syscall
>        fsinfo: AFS: Return information through the filesystem info syscall
>        fsinfo: NFS: Return information through the filesystem info syscall
>        fsinfo: CIFS: Return information through the filesystem info syscall
>
>
>   arch/x86/entry/syscalls/syscall_32.tbl |    2
>   arch/x86/entry/syscalls/syscall_64.tbl |    2
>   fs/afs/inode.c                         |   23 ++
>   fs/afs/super.c                         |   39 ++++
>   fs/cifs/cifsfs.c                       |   25 +++
>   fs/cifs/cifsfs.h                       |    4
>   fs/cifs/cifsglob.h                     |    8 +
>   fs/cifs/dir.c                          |    2
>   fs/cifs/inode.c                        |  124 ++++++++++---
>   fs/cifs/netmisc.c                      |    4
>   fs/exportfs/expfs.c                    |    4
>   fs/ext4/ext4.h                         |   24 ++-
>   fs/ext4/file.c                         |    2
>   fs/ext4/inode.c                        |   31 +++
>   fs/ext4/namei.c                        |    2
>   fs/ext4/super.c                        |   39 ++++
>   fs/ext4/symlink.c                      |    2
>   fs/nfs/inode.c                         |   45 ++++-
>   fs/nfs/internal.h                      |    1
>   fs/nfs/nfs4super.c                     |    1
>   fs/nfs/super.c                         |   58 ++++++
>   fs/ntfs/time.h                         |    2
>   fs/stat.c                              |  305 +++++++++++++++++++++++++++++---
>   fs/statfs.c                            |  218 +++++++++++++++++++++++
>   include/linux/fs.h                     |    7 +
>   include/linux/stat.h                   |   14 +
>   include/linux/syscalls.h               |    6 +
>   include/linux/time64.h                 |    2
>   include/uapi/linux/fcntl.h             |    2
>   include/uapi/linux/fs.h                |    7 +
>   include/uapi/linux/stat.h              |  185 +++++++++++++++++++
>   samples/Makefile                       |    3
>   samples/statx/Makefile                 |   13 +
>   samples/statx/test-fsinfo.c            |  179 +++++++++++++++++++
>   samples/statx/test-statx.c             |  273 +++++++++++++++++++++++++++++
>   35 files changed, 1558 insertions(+), 100 deletions(-)
>   create mode 100644 samples/statx/Makefile
>   create mode 100644 samples/statx/test-fsinfo.c
>   create mode 100644 samples/statx/test-statx.c
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
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> Please read the FAQ at  http://www.tux.org/lkml/
>

  parent reply	other threads:[~2015-11-20 16:50 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-20 14:54 David Howells
2015-11-20 14:54 ` [PATCH 01/12] Ext4: Fix extended timestamp encoding and decoding David Howells
     [not found]   ` <20151120145434.18930.89755.stgit-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org>
2015-11-24 17:37     ` Andreas Dilger
2015-11-24 17:37       ` Andreas Dilger
2015-11-24 19:36   ` Theodore Ts'o
     [not found]     ` <20151124193646.GA3482-AKGzg7BKzIDYtjvyW6yDsg@public.gmane.org>
2015-11-24 20:10       ` Arnd Bergmann
2015-11-24 20:10         ` Arnd Bergmann
2015-11-29  2:45         ` Theodore Ts'o
2015-11-29  2:45           ` Theodore Ts'o
     [not found]           ` <20151129024555.GA31968-AKGzg7BKzIDYtjvyW6yDsg@public.gmane.org>
2015-11-29 21:30             ` Arnd Bergmann
2015-11-29 21:30               ` Arnd Bergmann
2015-11-30 14:16               ` Theodore Ts'o
     [not found]                 ` <20151130141605.GA4316-AKGzg7BKzIDYtjvyW6yDsg@public.gmane.org>
2015-11-30 14:37                   ` Arnd Bergmann
2015-11-30 14:37                     ` Arnd Bergmann
2015-11-30 14:46                 ` Elmar Stellnberger
2015-11-26 15:28       ` David Howells
2015-11-26 15:28         ` David Howells
2015-11-20 14:54 ` [PATCH 02/12] statx: Provide IOC flags for Windows fs attributes David Howells
     [not found]   ` <20151120145447.18930.5308.stgit-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org>
2015-11-24 19:52     ` Theodore Ts'o
2015-11-24 19:52       ` Theodore Ts'o
2015-11-26 15:35   ` David Howells
     [not found]   ` <7976.1448552129-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org>
2015-11-26 16:01     ` David Howells
2015-11-26 16:01       ` David Howells
2015-11-26 22:10     ` Andreas Dilger
2015-11-26 22:10       ` Andreas Dilger
2015-11-20 14:54 ` [PATCH 03/12] statx: Add a system call to make enhanced file info available David Howells
     [not found]   ` <20151120145457.18930.79678.stgit-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org>
2015-11-24 20:21     ` Dave Chinner
2015-11-24 20:21       ` Dave Chinner
2015-12-04 12:06     ` Pavel Machek
2015-12-04 12:06       ` Pavel Machek
2015-12-21 23:21   ` David Howells
2015-11-20 14:55 ` [PATCH 04/12] statx: AFS: Return enhanced file attributes David Howells
2015-11-20 14:55 ` [PATCH 05/12] statx: Ext4: " David Howells
2015-11-20 14:55 ` [PATCH 06/12] statx: NFS: " David Howells
2015-11-20 14:55 ` [PATCH 07/12] statx: CIFS: Return enhanced attributes David Howells
2015-11-24 17:33   ` Steve French
2015-11-24 17:34   ` Steve French
2015-11-24 17:34     ` Steve French
2015-11-20 14:56 ` [PATCH 08/12] fsinfo: Add a system call to make enhanced filesystem info available David Howells
2015-11-20 14:56 ` [PATCH 09/12] fsinfo: Ext4: Return information through the filesystem info syscall David Howells
2015-11-20 14:56 ` [PATCH 10/12] fsinfo: AFS: " David Howells
2015-11-20 14:56 ` [PATCH 11/12] fsinfo: NFS: " David Howells
     [not found] ` <20151120145422.18930.72662.stgit-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org>
2015-11-20 14:56   ` [PATCH 12/12] fsinfo: CIFS: " David Howells
2015-11-20 14:56     ` David Howells
2015-11-24  8:11   ` [RFC][PATCH 00/12] Enhanced file stat system call Christoph Hellwig
2015-11-24  8:11     ` Christoph Hellwig
2015-11-20 16:19 ` Martin Steigerwald
2015-11-24  8:13   ` Christoph Hellwig
2015-11-24  8:48     ` Martin Steigerwald
2015-11-24  8:50       ` Christoph Hellwig
2015-11-20 16:28 ` David Howells
2015-11-20 16:28   ` David Howells
2015-11-20 16:35   ` Martin Steigerwald
     [not found]   ` <4495.1448036915-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org>
2015-11-25 17:51     ` J. Bruce Fields
2015-11-25 17:51       ` J. Bruce Fields
     [not found]       ` <20151125175153.GA30335-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2015-11-25 19:30         ` Andreas Dilger
2015-11-25 19:30           ` Andreas Dilger
2015-11-20 16:50 ` Casey Schaufler [this message]
     [not found]   ` <564F4F4E.8060603-iSGtlc1asvQWG2LlvL+J4A@public.gmane.org>
2015-11-24  8:15     ` Christoph Hellwig
2015-11-24  8:15       ` Christoph Hellwig
2015-11-24 14:43       ` Casey Schaufler
2015-11-24 16:28   ` Andreas Dilger
2015-11-26 15:19 ` David Howells
2015-11-26 22:06   ` Andreas Dilger

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