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From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Dave Jiang <dave.jiang@intel.com>
Cc: lczerner@redhat.com, jack@suse.cz, linux-nvdimm@lists.01.org,
	david@fromorbit.com, linux-xfs@vger.kernel.org,
	zwisler@kernel.org, linux-fsdevel@vger.kernel.org, tytso@mit.edu,
	linux-ext4@vger.kernel.org, hch@lst.de
Subject: Re: [PATCH v2 2/2] [PATCH] xfs: Close race between direct IO and xfs_break_layouts()
Date: Fri, 10 Aug 2018 09:02:43 -0700	[thread overview]
Message-ID: <20180810160243.GF4203@magnolia> (raw)
In-Reply-To: <dc539a4d-7f9c-11c6-e63b-93ebb7f7ff9d@intel.com>

On Fri, Aug 10, 2018 at 08:54:00AM -0700, Dave Jiang wrote:
> 
> 
> On 08/10/2018 08:48 AM, Darrick J. Wong wrote:
> > On Wed, Aug 08, 2018 at 10:31:40AM -0700, Dave Jiang wrote:
> >> This patch is the duplicate of ross's fix for ext4 for xfs.
> >>
> >> If the refcount of a page is lowered between the time that it is returned
> >> by dax_busy_page() and when the refcount is again checked in
> >> xfs_break_layouts() => ___wait_var_event(), the waiting function
> >> xfs_wait_dax_page() will never be called.  This means that
> >> xfs_break_layouts() will still have 'retry' set to false, so we'll stop
> >> looping and never check the refcount of other pages in this inode.
> >>
> >> Instead, always continue looping as long as dax_layout_busy_page() gives us
> >> a page which it found with an elevated refcount.
> >>
> >> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> >> Reviewed-by: Jan Kara <jack@suse.cz>
> >> ---
> >>
> >> Sorry resend, forgot to add Jan's reviewed-by.
> >>
> >> v2:
> >> - Rename parameter from did_unlock to retry (Jan)
> >>
> >>  fs/xfs/xfs_file.c |    9 ++++-----
> >>  1 file changed, 4 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> >> index a3e7767a5715..cd6f0d8c4922 100644
> >> --- a/fs/xfs/xfs_file.c
> >> +++ b/fs/xfs/xfs_file.c
> >> @@ -721,12 +721,10 @@ xfs_file_write_iter(
> >>  
> >>  static void
> >>  xfs_wait_dax_page(
> >> -	struct inode		*inode,
> >> -	bool			*did_unlock)
> >> +	struct inode		*inode)
> >>  {
> >>  	struct xfs_inode        *ip = XFS_I(inode);
> >>  
> >> -	*did_unlock = true;
> >>  	xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
> >>  	schedule();
> >>  	xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
> >> @@ -736,7 +734,7 @@ static int
> >>  xfs_break_dax_layouts(
> >>  	struct inode		*inode,
> >>  	uint			iolock,
> >> -	bool			*did_unlock)
> >> +	bool			*retry)
> > 
> > Uhhh, this hunk doesn't apply.  xfs_break_dax_layouts doesn't have an
> > iolock parameter anymore; was this not generated off of xfs for-next?
> 
> Sorry. It was generated against 4.18-rc8. I'll respin patch against xfs
> for-next.

I think it's just a matter of taking the old patch and changing
"did_unlock" to "retry", right?  If so, I'll just change that and be
done with this one. :)

--D

> > 
> > --D
> > 
> >>  {
> >>  	struct page		*page;
> >>  
> >> @@ -746,9 +744,10 @@ xfs_break_dax_layouts(
> >>  	if (!page)
> >>  		return 0;
> >>  
> >> +	*retry = true;
> >>  	return ___wait_var_event(&page->_refcount,
> >>  			atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE,
> >> -			0, 0, xfs_wait_dax_page(inode, did_unlock));
> >> +			0, 0, xfs_wait_dax_page(inode));
> >>  }
> >>  
> >>  int
> >>
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
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  reply	other threads:[~2018-08-10 16:02 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-08 17:31 [PATCH v2 2/2] [PATCH] xfs: Close race between direct IO and xfs_break_layouts() Dave Jiang
2018-08-10 15:48 ` Darrick J. Wong
2018-08-10 15:54   ` Dave Jiang
2018-08-10 16:02     ` Darrick J. Wong [this message]
2018-08-10 16:05       ` Dave Jiang
2018-08-10 18:31 ` Eric Sandeen
2018-08-10 19:23   ` Dave Jiang
2018-08-10 19:24     ` Ross Zwisler
2018-08-10 19:26       ` Eric Sandeen
  -- strict thread matches above, loose matches on Subject: below --
2018-08-08 17:25 [PATCH v2 1/2] ext4: Close race between direct IO and ext4_break_layouts() Dave Jiang
2018-08-08 17:26 ` [PATCH v2 2/2] [PATCH] xfs: Close race between direct IO and xfs_break_layouts() Dave Jiang
2018-08-09  8:57   ` Jan Kara
2018-08-09 16:21     ` Dave Jiang

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