From: Dave Chinner <david@fromorbit.com>
To: Amir Goldstein <amir73il@gmail.com>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>,
Christoph Hellwig <hch@lst.de>,
linux-xfs <linux-xfs@vger.kernel.org>,
Olga Kornievskaia <olga.kornievskaia@gmail.com>,
Luis Henriques <lhenriques@suse.com>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-api@vger.kernel.org, ceph-devel@vger.kernel.org,
Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
CIFS <linux-cifs@vger.kernel.org>
Subject: Re: [PATCH v3 06/13] vfs: introduce file_modified() helper
Date: Thu, 30 May 2019 07:41:45 +1000 [thread overview]
Message-ID: <20190529214145.GC29573@dread.disaster.area> (raw)
In-Reply-To: <CAOQ4uxgsMLTPtYaQwwNHo3NrzXz9u=YGc2v6Pg8TSo7-xFrqQQ@mail.gmail.com>
On Wed, May 29, 2019 at 10:08:44PM +0300, Amir Goldstein wrote:
> On Wed, May 29, 2019 at 9:27 PM Darrick J. Wong <darrick.wong@oracle.com> wrote:
> >
> > On Wed, May 29, 2019 at 08:43:10PM +0300, Amir Goldstein wrote:
> > > The combination of file_remove_privs() and file_update_mtime() is
> > > quite common in filesystem ->write_iter() methods.
> > >
> > > Modelled after the helper file_accessed(), introduce file_modified()
> > > and use it from generic_remap_file_range_prep().
> > >
> > > Note that the order of calling file_remove_privs() before
> > > file_update_mtime() in the helper was matched to the more common order by
> > > filesystems and not the current order in generic_remap_file_range_prep().
> > >
> > > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > > ---
> > > fs/inode.c | 20 ++++++++++++++++++++
> > > fs/read_write.c | 21 +++------------------
> > > include/linux/fs.h | 2 ++
> > > 3 files changed, 25 insertions(+), 18 deletions(-)
> > >
> > > diff --git a/fs/inode.c b/fs/inode.c
> > > index df6542ec3b88..2885f2f2c7a5 100644
> > > --- a/fs/inode.c
> > > +++ b/fs/inode.c
> > > @@ -1899,6 +1899,26 @@ int file_update_time(struct file *file)
> > > }
> > > EXPORT_SYMBOL(file_update_time);
> > >
> > > +/* Caller must hold the file's inode lock */
> > > +int file_modified(struct file *file)
> > > +{
> > > + int err;
> > > +
> > > + /*
> > > + * Clear the security bits if the process is not being run by root.
> > > + * This keeps people from modifying setuid and setgid binaries.
> > > + */
> > > + err = file_remove_privs(file);
> > > + if (err)
> > > + return err;
> > > +
> > > + if (likely(file->f_mode & FMODE_NOCMTIME))
> >
> > I would not have thought NOCMTIME is likely?
> >
> > Maybe it is for io requests coming from overlayfs, but for regular uses
> > I don't think that's true.
>
> Nope that's a typo. Good spotting.
> Overlayfs doesn't set FMODE_NOCMTIME (yet). Only xfs does from
> XFS_IOC_OPEN_BY_HANDLE, but I think Dave said that is a deprecated
> API. so should have been very_unlikely().
It is most definitely not a deprecated API. I don't know where you
got that idea from. It's used explicitly by the xfs utilities to
perform invisible IO. Anyone who runs xfs_fsr or xfsdump or has an
application that links to libhandle is using XFS_IOC_OPEN_BY_HANDLE
and FMODE_NOCMTIME....
-Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2019-05-29 21:41 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-29 17:43 [PATCH v3 00/13] Fixes for major copy_file_range() issues Amir Goldstein
2019-05-29 17:43 ` [PATCH v3 01/13] vfs: introduce generic_copy_file_range() Amir Goldstein
2019-05-29 17:43 ` [PATCH v3 02/13] vfs: no fallback for ->copy_file_range Amir Goldstein
2019-05-29 17:43 ` [PATCH v3 03/13] vfs: introduce generic_file_rw_checks() Amir Goldstein
2019-05-29 17:43 ` [PATCH v3 04/13] vfs: remove redundant checks from generic_remap_checks() Amir Goldstein
2019-05-29 18:23 ` Darrick J. Wong
2019-05-29 17:43 ` [PATCH v3 05/13] vfs: add missing checks to copy_file_range Amir Goldstein
2019-05-29 18:24 ` Darrick J. Wong
2019-05-29 17:43 ` [PATCH v3 06/13] vfs: introduce file_modified() helper Amir Goldstein
2019-05-29 18:27 ` Darrick J. Wong
2019-05-29 19:08 ` Amir Goldstein
2019-05-29 19:23 ` Amir Goldstein
2019-05-29 21:41 ` Dave Chinner [this message]
2019-05-29 17:43 ` [PATCH v3 07/13] xfs: use " Amir Goldstein
2019-05-29 18:31 ` Darrick J. Wong
2019-05-29 19:10 ` Amir Goldstein
2019-05-29 19:13 ` Darrick J. Wong
2019-05-29 17:43 ` [PATCH v3 08/13] vfs: copy_file_range needs to strip setuid bits and update timestamps Amir Goldstein
2019-05-29 18:33 ` Darrick J. Wong
2019-05-29 21:08 ` Amir Goldstein
2019-05-29 17:43 ` [PATCH v3 09/13] ceph: " Amir Goldstein
2019-05-29 19:43 ` Amir Goldstein
2019-05-29 17:43 ` [PATCH v3 10/13] cifs: " Amir Goldstein
2019-05-29 19:36 ` Amir Goldstein
2019-05-29 17:43 ` [PATCH v3 11/13] fuse: " Amir Goldstein
2019-05-29 19:37 ` Amir Goldstein
2019-05-29 20:07 ` Miklos Szeredi
2019-05-29 17:43 ` [PATCH v3 12/13] nfs: " Amir Goldstein
2019-05-29 19:34 ` Amir Goldstein
2019-05-29 20:02 ` Trond Myklebust
2019-05-29 21:00 ` Amir Goldstein
2019-05-29 17:43 ` [PATCH v3 13/13] vfs: allow copy_file_range to copy across devices Amir Goldstein
2019-05-29 20:09 ` Olga Kornievskaia
2019-05-29 21:03 ` Amir Goldstein
2019-06-03 20:39 ` Olga Kornievskaia
2019-06-04 4:11 ` Amir Goldstein
2019-05-29 17:43 ` [PATCH v3 14/13] man-pages: copy_file_range updates Amir Goldstein
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