From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Samuel Subject: Re: btrfs-convert fails Date: Tue, 02 Nov 2010 11:43:11 +1100 Message-ID: <4CCF5E9F.1040001@csamuel.org> References: <20101101104943.00007ff9@unknown> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 To: linux-btrfs@vger.kernel.org Return-path: In-Reply-To: List-ID: On 01/11/10 23:20, cwillu wrote: > Problems resulting from powerloss should be limited to faulty hardware > (in which case you're screwed regardless of the filesystem) and lack > of barrier support (which should show up in dmesg soon after the first > write goes to disk). Note that for until 2.6.31 the DM layer didn't support barrier operations fully, according to this email: http://www.spinics.net/lists/linux-ext4/msg15789.html # Barrier infrastructure started to get added to the DM # core in 2.6.30, see: http://git.kernel.org/linus/af7e466a1ace # # But barriers were not enabled for all DM targets (_except_ # dm-multipath) until 2.6.31. So 2.6.31's dm-crypt does support # barriers, see: http://git.kernel.org/linus/647c7db14ef9 # # If the underlying device(s) support barriers DM should # faithfully pass them on (again except for dm-multipath). # Also, requests with barriers that result in -EOPNOTSUPP # are retried without the barrier, see: # http://git.kernel.org/linus/51aa32284958 cheers, Chris -- Chris Samuel : http://www.csamuel.org/ : Melbourne, VIC