From: Dan Williams <dan.j.williams@intel.com>
To: Christoph Hellwig <hch@lst.de>
Cc: "linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
Jan Kara <jack@suse.cz>, Matthew Wilcox <mawilcox@microsoft.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-xfs <linux-xfs@vger.kernel.org>,
Linux MM <linux-mm@kvack.org>, Jeff Moyer <jmoyer@redhat.com>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 14/15] dax: associate mappings with inodes, and warn if dma collides with truncate
Date: Tue, 19 Dec 2017 17:11:38 -0800 [thread overview]
Message-ID: <CAPcyv4irj_+pJdX1SO6MjsxURcKm8--i_QvyudgHTZE2w4w-sA@mail.gmail.com> (raw)
In-Reply-To: <20171110090818.GE4895@lst.de>
On Fri, Nov 10, 2017 at 1:08 AM, Christoph Hellwig <hch@lst.de> wrote:
>> + struct {
>> + /*
>> + * ZONE_DEVICE pages are never on an lru or handled by
>> + * a slab allocator, this points to the hosting device
>> + * page map.
>> + */
>> + struct dev_pagemap *pgmap;
>> + /*
>> + * inode association for MEMORY_DEVICE_FS_DAX page-idle
>> + * callbacks. Note that we don't use ->mapping since
>> + * that has hard coded page-cache assumptions in
>> + * several paths.
>> + */
>
> What assumptions? I'd much rather fix those up than having two fields
> that have the same functionality.
[ Reviving this old thread where you asked why I introduce page->inode
instead of reusing page->mapping ]
For example, xfs_vm_set_page_dirty() assumes that page->mapping being
non-NULL indicates a typical page cache page, this is a false
assumption for DAX. My guess at a fix for this is to add
pagecache_page() checks to locations like this, but I worry about how
to find them all. Where pagecache_page() is:
bool pagecache_page(struct page *page)
{
if (!page->mapping)
return false;
if (!IS_DAX(page->mapping->host))
return false;
return true;
}
Otherwise we go off the rails:
WARNING: CPU: 27 PID: 1783 at fs/xfs/xfs_aops.c:1468
xfs_vm_set_page_dirty+0xf3/0x1b0 [xfs]
[..]
CPU: 27 PID: 1783 Comm: dma-collision Tainted: G O
4.15.0-rc2+ #984
[..]
Call Trace:
set_page_dirty_lock+0x40/0x60
bio_set_pages_dirty+0x37/0x50
iomap_dio_actor+0x2b7/0x3b0
? iomap_dio_zero+0x110/0x110
iomap_apply+0xa4/0x110
iomap_dio_rw+0x29e/0x3b0
? iomap_dio_zero+0x110/0x110
? xfs_file_dio_aio_read+0x7c/0x1a0 [xfs]
xfs_file_dio_aio_read+0x7c/0x1a0 [xfs]
xfs_file_read_iter+0xa0/0xc0 [xfs]
__vfs_read+0xf9/0x170
vfs_read+0xa6/0x150
SyS_pread64+0x93/0xb0
entry_SYSCALL_64_fastpath+0x1f/0x96
next prev parent reply other threads:[~2017-12-20 1:11 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-31 23:21 [PATCH 00/15] dax: prep work for fixing dax-dma vs truncate collisions Dan Williams
2017-10-31 23:21 ` [PATCH 01/15] dax: quiet bdev_dax_supported() Dan Williams
2017-11-02 20:11 ` Christoph Hellwig
2017-10-31 23:21 ` [PATCH 02/15] mm, dax: introduce pfn_t_special() Dan Williams
2017-11-03 2:32 ` Michael Ellerman
2017-10-31 23:21 ` [PATCH 03/15] dax: require 'struct page' by default for filesystem dax Dan Williams
2017-10-31 23:21 ` [PATCH 04/15] brd: remove dax support Dan Williams
2017-11-02 20:12 ` Christoph Hellwig
2017-11-04 16:31 ` Jens Axboe
2017-10-31 23:22 ` [PATCH 05/15] dax: stop using VM_MIXEDMAP for dax Dan Williams
2017-10-31 23:22 ` [PATCH 06/15] dax: stop using VM_HUGEPAGE " Dan Williams
2017-10-31 23:22 ` [PATCH 07/15] dax: stop requiring a live device for dax_flush() Dan Williams
2017-11-02 20:12 ` Christoph Hellwig
2017-10-31 23:22 ` [PATCH 08/15] dax: store pfns in the radix Dan Williams
2017-10-31 23:22 ` [PATCH 09/15] tools/testing/nvdimm: add 'bio_delay' mechanism Dan Williams
2017-10-31 23:22 ` [PATCH 10/15] IB/core: disable memory registration of fileystem-dax vmas Dan Williams
2017-11-02 20:13 ` Christoph Hellwig
2017-11-02 21:06 ` Dan Williams
2017-10-31 23:22 ` [PATCH 11/15] [media] v4l2: disable filesystem-dax mapping support Dan Williams
2017-10-31 23:22 ` [PATCH 12/15] mm, dax: enable filesystems to trigger page-idle callbacks Dan Williams
2017-11-10 9:04 ` Christoph Hellwig
2017-10-31 23:22 ` [PATCH 13/15] mm, devmap: introduce CONFIG_DEVMAP_MANAGED_PAGES Dan Williams
2017-11-10 9:06 ` Christoph Hellwig
2017-10-31 23:22 ` [PATCH 14/15] dax: associate mappings with inodes, and warn if dma collides with truncate Dan Williams
2017-11-10 9:08 ` Christoph Hellwig
2017-12-20 1:11 ` Dan Williams [this message]
2017-12-20 14:38 ` Jan Kara
2017-12-20 22:41 ` Dan Williams
2017-12-21 12:14 ` Jan Kara
2017-12-21 17:31 ` Dan Williams
2017-12-22 8:51 ` Jan Kara
2017-12-20 22:14 ` Dave Chinner
2017-10-31 23:22 ` [PATCH 15/15] wait_bit: introduce {wait_on,wake_up}_devmap_idle Dan Williams
2017-11-10 9:09 ` Christoph Hellwig
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