From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Ira Weiny <ira.weiny@intel.com>
Cc: Jeff Moyer <jmoyer@redhat.com>,
Dan Williams <dan.j.williams@intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Dave Chinner <david@fromorbit.com>,
Christoph Hellwig <hch@lst.de>,
"Theodore Y. Ts'o" <tytso@mit.edu>, Jan Kara <jack@suse.cz>,
linux-ext4 <linux-ext4@vger.kernel.org>,
linux-xfs <linux-xfs@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH v3 00/12] Enable per-file/directory DAX operations V3
Date: Thu, 20 Feb 2020 09:00:35 -0800 [thread overview]
Message-ID: <20200220170035.GY9506@magnolia> (raw)
In-Reply-To: <20200220164957.GB20772@iweiny-DESK2.sc.intel.com>
On Thu, Feb 20, 2020 at 08:49:57AM -0800, Ira Weiny wrote:
> On Thu, Feb 20, 2020 at 08:30:24AM -0800, Darrick J. Wong wrote:
> > On Thu, Feb 20, 2020 at 08:20:28AM -0800, Ira Weiny wrote:
> > > On Tue, Feb 18, 2020 at 03:54:30PM -0800, 'Ira Weiny' wrote:
> > > > On Tue, Feb 18, 2020 at 09:22:58AM -0500, Jeff Moyer wrote:
> > > > > Ira Weiny <ira.weiny@intel.com> writes:
> > > > > > If my disassembly of read_pages is correct it looks like readpage is null which
> > > > > > makes sense because all files should be IS_DAX() == true due to the mount option...
> > > > > >
> > > > > > But tracing code indicates that the patch:
> > > > > >
> > > > > > fs: remove unneeded IS_DAX() check
> > > > > >
> > > > > > ... may be the culprit and the following fix may work...
> > > > > >
> > > > > > diff --git a/mm/filemap.c b/mm/filemap.c
> > > > > > index 3a7863ba51b9..7eaf74a2a39b 100644
> > > > > > --- a/mm/filemap.c
> > > > > > +++ b/mm/filemap.c
> > > > > > @@ -2257,7 +2257,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
> > > > > > if (!count)
> > > > > > goto out; /* skip atime */
> > > > > >
> > > > > > - if (iocb->ki_flags & IOCB_DIRECT) {
> > > > > > + if (iocb->ki_flags & IOCB_DIRECT || IS_DAX(inode)) {
> > > > > > struct file *file = iocb->ki_filp;
> > > > > > struct address_space *mapping = file->f_mapping;
> > > > > > struct inode *inode = mapping->host;
> > > > >
> > > > > Well, you'll have to up-level the inode variable instantiation,
> > > > > obviously. That solves this particular issue.
> > > >
> > > > Well... This seems to be a random issue. I've had BMC issues with
> > > > my server most of the day... But even with this patch I still get the failure
> > > > in read_pages(). :-/
> > > >
> > > > And I have gotten it to both succeed and fail with qemu... :-/
> > >
> > > ... here is the fix. I made the change in xfs_diflags_to_linux() early on with
> > > out factoring in the flag logic changes we have agreed upon...
> > >
> > > diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> > > index 62d9f622bad1..d592949ad396 100644
> > > --- a/fs/xfs/xfs_ioctl.c
> > > +++ b/fs/xfs/xfs_ioctl.c
> > > @@ -1123,11 +1123,11 @@ xfs_diflags_to_linux(
> > > inode->i_flags |= S_NOATIME;
> > > else
> > > inode->i_flags &= ~S_NOATIME;
> > > - if (xflags & FS_XFLAG_DAX)
> > > +
> > > + if (xfs_inode_enable_dax(ip))
> > > inode->i_flags |= S_DAX;
> > > else
> > > inode->i_flags &= ~S_DAX;
> > > -
> > > }
> > >
> > > But the one thing which tripped me up, and concerns me, is we have 2 functions
> > > which set the inode flags.
> > >
> > > xfs_diflags_to_iflags()
> > > xfs_diflags_to_linux()
> > >
> > > xfs_diflags_to_iflags() is geared toward initialization but logically they do
> > > the same thing. I see no reason to keep them separate. Does anyone?
> > >
> > > Based on this find, the discussion on behavior in this thread, and the comments
> > > from Dave I'm reworking the series because the flag check/set functions have
> > > all changed and I really want to be as clear as possible with both the patches
> > > and the resulting code.[*] So v4 should be out today including attempting to
> > > document what we have discussed here and being as clear as possible on the
> > > behavior. :-D
> > >
> > > Thanks so much for testing this!
> > >
> > > Ira
> > >
> > > [*] I will probably throw in a patch to remove xfs_diflags_to_iflags() as I
> > > really don't see a reason to keep it.
> > >
> >
> > I prefer you keep the one in xfs_iops.c since ioctls are a higher level
> > function than general inode operations.
>
> Makes sense. Do you prefer the xfs_diflags_to_iflags() name as well?
I don't really care one way or another, so ... iflags wins by arbitrary
choice! 8)
--D
> Ira
>
> >
> > --D
prev parent reply other threads:[~2020-02-20 17:01 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-08 19:34 [PATCH v3 00/12] Enable per-file/directory DAX operations V3 ira.weiny
2020-02-08 19:34 ` [PATCH v3 01/12] fs/stat: Define DAX statx attribute ira.weiny
2020-02-08 19:34 ` [PATCH v3 02/12] fs/xfs: Isolate the physical DAX flag from effective ira.weiny
2020-02-08 19:34 ` [PATCH v3 03/12] fs/xfs: Separate functionality of xfs_inode_supports_dax() ira.weiny
2020-02-11 5:47 ` Dave Chinner
2020-02-11 16:13 ` Ira Weiny
2020-02-08 19:34 ` [PATCH v3 04/12] fs/xfs: Clean up DAX support check ira.weiny
2020-02-11 5:57 ` Dave Chinner
2020-02-11 16:28 ` Ira Weiny
2020-02-11 20:38 ` Dave Chinner
2020-02-08 19:34 ` [PATCH v3 05/12] fs: remove unneeded IS_DAX() check ira.weiny
2020-02-11 5:34 ` Dave Chinner
2020-02-11 16:38 ` Ira Weiny
2020-02-11 20:41 ` Dave Chinner
2020-02-12 16:04 ` Ira Weiny
2020-02-08 19:34 ` [PATCH v3 06/12] fs/xfs: Check if the inode supports DAX under lock ira.weiny
2020-02-11 6:16 ` Dave Chinner
2020-02-11 17:55 ` Ira Weiny
2020-02-11 20:42 ` Dave Chinner
2020-02-12 16:10 ` Ira Weiny
2020-02-08 19:34 ` [PATCH v3 07/12] fs: Add locking for a dynamic DAX state ira.weiny
2020-02-11 8:00 ` Dave Chinner
2020-02-11 20:14 ` Ira Weiny
2020-02-11 20:59 ` Dan Williams
2020-02-11 21:49 ` Dave Chinner
2020-02-12 6:31 ` Darrick J. Wong
2020-02-08 19:34 ` [PATCH v3 08/12] fs/xfs: Clarify lockdep dependency for xfs_isilocked() ira.weiny
2020-02-08 19:34 ` [PATCH v3 09/12] fs/xfs: Add write DAX lock to xfs layer ira.weiny
2020-02-08 19:34 ` [PATCH v3 10/12] fs: Prevent DAX state change if file is mmap'ed ira.weiny
2020-02-08 19:34 ` [PATCH v3 11/12] fs/xfs: Clean up locking in dax invalidate ira.weiny
2020-02-08 19:34 ` [PATCH v3 12/12] fs/xfs: Allow toggle of effective DAX flag ira.weiny
2020-02-10 15:15 ` [PATCH v3 00/12] Enable per-file/directory DAX operations V3 Jeff Moyer
2020-02-11 20:17 ` Ira Weiny
2020-02-12 19:49 ` Jeff Moyer
2020-02-13 19:01 ` Ira Weiny
2020-02-13 19:05 ` Ira Weiny
2020-02-13 19:58 ` Darrick J. Wong
2020-02-13 23:29 ` Ira Weiny
2020-02-14 0:16 ` Dan Williams
2020-02-14 20:06 ` Ira Weiny
2020-02-14 21:23 ` Jeff Moyer
2020-02-14 21:58 ` Ira Weiny
2020-02-14 22:06 ` Jeff Moyer
2020-02-14 22:58 ` Jeff Moyer
2020-02-14 23:03 ` Jeff Moyer
2020-02-18 2:35 ` Ira Weiny
2020-02-18 14:22 ` Jeff Moyer
2020-02-18 23:54 ` Ira Weiny
2020-02-20 16:20 ` Ira Weiny
2020-02-20 16:30 ` Darrick J. Wong
2020-02-20 16:49 ` Ira Weiny
2020-02-20 17:00 ` Darrick J. Wong [this message]
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