From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Jiang Subject: Re: [PATCH v2 2/2] [PATCH] xfs: Close race between direct IO and xfs_break_layouts() Date: Thu, 9 Aug 2018 09:21:25 -0700 Message-ID: References: <153374910694.40645.17166196534680658204.stgit@djiang5-desk3.ch.intel.com> <153374915981.40645.3350205963852459041.stgit@djiang5-desk3.ch.intel.com> <20180809085706.GB5069@quack2.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: tytso-3s7WtUTddSA@public.gmane.org, linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org, darrick.wong-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, david-FqsqvQoI3Ljby3iVrkZq2A@public.gmane.org, linux-xfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, zwisler-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, lczerner-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, hch-jcswGhMUV9g@public.gmane.org To: Jan Kara Return-path: In-Reply-To: <20180809085706.GB5069-4I4JzKEfoa/jFM9bn6wA6Q@public.gmane.org> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" List-Id: linux-ext4.vger.kernel.org On 08/09/2018 01:57 AM, Jan Kara wrote: > On Wed 08-08-18 10:26:36, 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 > > I think I gave you my reviewed-by tag already for the previous version. But > here it is again: > > Reviewed-by: Jan Kara Yes you did. I forgot to append it when I sent it out the first time. I resent it. :) > > Honza > >> --- >> >> 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) >> { >> 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 >>