From: Dave Chinner <david@fromorbit.com>
To: Jan Kara <jack@suse.cz>
Cc: "Williams, Dan J" <dan.j.williams@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"jmoyer@redhat.com" <jmoyer@redhat.com>,
"hch@lst.de" <hch@lst.de>, "axboe@fb.com" <axboe@fb.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
"willy@linux.intel.com" <willy@linux.intel.com>,
"ross.zwisler@linux.intel.com" <ross.zwisler@linux.intel.com>
Subject: Re: [PATCH 5/5] block: enable dax for raw block devices
Date: Mon, 26 Oct 2015 08:22:47 +1100 [thread overview]
Message-ID: <20151025212247.GI19199@dastard> (raw)
In-Reply-To: <20151022210818.GC8670@quack.suse.cz>
On Thu, Oct 22, 2015 at 11:08:18PM +0200, Jan Kara wrote:
> Ugh2: Now I realized that DAX mmap isn't safe wrt fs freezing even for
> filesystems since there's nothing which writeprotects pages that are
> writeably mapped. In normal path, page writeback does this but that doesn't
> happen for DAX. I remember we once talked about this but it got lost.
> We need something like walk all filesystem inodes during fs freeze and
> writeprotect all pages that are mapped. But that's going to be slow...
fsync() has the same problem - we have no record of the pages that
need to be committed and then write protected when fsync() is called
after write()...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
WARNING: multiple messages have this Message-ID (diff)
From: Dave Chinner <david@fromorbit.com>
To: Jan Kara <jack@suse.cz>
Cc: "Williams, Dan J" <dan.j.williams@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"jmoyer@redhat.com" <jmoyer@redhat.com>,
"hch@lst.de" <hch@lst.de>, "axboe@fb.com" <axboe@fb.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
"willy@linux.intel.com" <willy@linux.intel.com>,
"ross.zwisler@linux.intel.com" <ross.zwisler@linux.intel.com>
Subject: Re: [PATCH 5/5] block: enable dax for raw block devices
Date: Mon, 26 Oct 2015 08:22:47 +1100 [thread overview]
Message-ID: <20151025212247.GI19199@dastard> (raw)
In-Reply-To: <20151022210818.GC8670@quack.suse.cz>
On Thu, Oct 22, 2015 at 11:08:18PM +0200, Jan Kara wrote:
> Ugh2: Now I realized that DAX mmap isn't safe wrt fs freezing even for
> filesystems since there's nothing which writeprotects pages that are
> writeably mapped. In normal path, page writeback does this but that doesn't
> happen for DAX. I remember we once talked about this but it got lost.
> We need something like walk all filesystem inodes during fs freeze and
> writeprotect all pages that are mapped. But that's going to be slow...
fsync() has the same problem - we have no record of the pages that
need to be committed and then write protected when fsync() is called
after write()...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2015-10-25 21:22 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-22 6:41 [PATCH 0/5] block, dax: updates for 4.4 Dan Williams
2015-10-22 6:41 ` Dan Williams
2015-10-22 6:41 ` [PATCH 1/5] pmem, dax: clean up clear_pmem() Dan Williams
2015-10-22 6:41 ` Dan Williams
2015-10-22 6:41 ` [PATCH 2/5] dax: increase granularity of dax_clear_blocks() operations Dan Williams
2015-10-22 6:41 ` Dan Williams
2015-10-22 9:26 ` Jan Kara
2015-10-22 9:26 ` Jan Kara
2015-10-22 6:41 ` [PATCH 3/5] block, dax: fix lifetime of in-kernel dax mappings with dax_map_atomic() Dan Williams
2015-10-22 6:41 ` Dan Williams
2015-10-22 6:42 ` [PATCH 4/5] block: introduce file_bd_inode() Dan Williams
2015-10-22 6:42 ` Dan Williams
2015-10-22 9:45 ` Jan Kara
2015-10-22 9:45 ` Jan Kara
2015-10-22 15:41 ` Dan Williams
2015-10-22 15:41 ` Dan Williams
2015-10-22 6:42 ` [PATCH 5/5] block: enable dax for raw block devices Dan Williams
2015-10-22 6:42 ` Dan Williams
2015-10-22 9:35 ` Jan Kara
2015-10-22 9:35 ` Jan Kara
2015-10-22 16:05 ` Williams, Dan J
2015-10-22 16:05 ` Williams, Dan J
2015-10-22 21:08 ` Jan Kara
2015-10-22 21:08 ` Jan Kara
2015-10-22 23:41 ` Williams, Dan J
2015-10-22 23:41 ` Williams, Dan J
2015-10-24 12:21 ` Jan Kara
2015-10-24 12:21 ` Jan Kara
2015-10-23 23:32 ` Dan Williams
2015-10-23 23:32 ` Dan Williams
2015-10-24 14:49 ` Jan Kara
2015-10-24 14:49 ` Jan Kara
2015-10-25 21:22 ` Dave Chinner [this message]
2015-10-25 21:22 ` Dave Chinner
2015-10-26 2:48 ` Dan Williams
2015-10-26 2:48 ` Dan Williams
2015-10-26 6:23 ` Dave Chinner
2015-10-26 6:23 ` Dave Chinner
2015-10-26 7:20 ` Jan Kara
2015-10-26 7:20 ` Jan Kara
2015-10-26 8:56 ` Dan Williams
2015-10-26 8:56 ` Dan Williams
2015-10-26 22:19 ` Dave Chinner
2015-10-26 22:19 ` Dave Chinner
2015-10-27 22:55 ` Ross Zwisler
2015-10-27 22:55 ` Ross Zwisler
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