[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20180316190443.GF3671@lst.de>
Date: Fri, 16 Mar 2018 20:04:43 +0100
From: Christoph Hellwig <hch@....de>
To: Dan Williams <dan.j.williams@...el.com>
Cc: linux-nvdimm@...ts.01.org,
"Darrick J. Wong" <darrick.wong@...cle.com>,
Ross Zwisler <ross.zwisler@...ux.intel.com>,
Dave Chinner <david@...morbit.com>,
Christoph Hellwig <hch@....de>, linux-xfs@...r.kernel.org,
linux-fsdevel@...r.kernel.org, jack@...e.cz,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 12/15] xfs: require mmap lock for xfs_break_layouts()
On Thu, Mar 15, 2018 at 08:52:29AM -0700, Dan Williams wrote:
> In preparation for adding coordination between truncate operations and
> busy dax-pages, extend xfs_break_layouts() to assume it must be called
> with the mmap lock held. This locking scheme will be required for
> coordinating the break of 'dax layouts' (non-idle dax (ZONE_DEVICE)
> pages mapped into the file's address space).
This requirement wasn't really there in the last series, why do we
require it now?
As far as I can tell all we'd need is to just drop this assert:
> - ASSERT(xfs_isilocked(ip, XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL));
> + ASSERT(xfs_isilocked(ip, XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL
> + | XFS_MMAPLOCK_EXCL));
entirely.
> while ((error = break_layout(inode, false) == -EWOULDBLOCK)) {
> xfs_iunlock(ip, *iolock);
> error = break_layout(inode, true);
> - *iolock = XFS_IOLOCK_EXCL;
> + *iolock &= ~XFS_IOLOCK_SHARED;
> + *iolock |= XFS_IOLOCK_EXCL;
> xfs_ilock(ip, *iolock);
And take this one hunk from your patch.
To enable the DAX use case.
Powered by blists - more mailing lists