Messages in this thread Patch in this message | | | Date | Fri, 17 Oct 2014 15:42:02 +0000 (UTC) | From | Mathieu Desnoyers <> | Subject | Re: [PATCH v11 20/21] ext4: Add DAX functionality |
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----- Original Message ----- > From: "Matthew Wilcox" <willy@linux.intel.com> > To: "Mathieu Desnoyers" <mathieu.desnoyers@efficios.com> > Cc: "Matthew Wilcox" <matthew.r.wilcox@intel.com>, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, > linux-kernel@vger.kernel.org, "Ross Zwisler" <ross.zwisler@linux.intel.com> > Sent: Friday, October 17, 2014 12:16:24 AM > Subject: Re: [PATCH v11 20/21] ext4: Add DAX functionality > [...] > On Thu, Oct 16, 2014 at 02:56:25PM +0200, Mathieu Desnoyers wrote: > > > @@ -3572,6 +3579,11 @@ static int ext4_fill_super(struct super_block *sb, > > > void *data, int silent) > > > "both data=journal and dioread_nolock"); > > > goto failed_mount; > > > } > > > + if (test_opt(sb, DAX)) { > > > + ext4_msg(sb, KERN_ERR, "can't mount with " > > > + "both data=journal and dax"); > > > > This limitation regarding ext4 and dax should be documented in dax > > Documentation. > > Maybe the ext4 documentation too? It seems kind of obvious to me that if > ypu're enabling in-place-updates that you can't journal the data you're > updating (well ... you could implement undo-log journalling, I suppose, > which would be quite a change for ext4)
Yes, we could document this limitation in general for all journalling FS within DAX documentation, and then document it specifically per-FS in the FS documentation.
Thanks,
Mathieu
-- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
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