From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 10AA919B3F9 for ; Thu, 25 Jul 2024 14:14:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.95.11.211 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721916859; cv=none; b=Izf1HCJr0AJt08tV5g0cD5TSmIlvK+CHELfIl7YjLtUStCvv3lUjnRpf7Xk5pU1i7qn2NWkB/INOInS1ewViMkW73UubxyzR2fBTNvY1DAkNvN5hHeM6Trrk+f7qDr+pesjEPubgjmsfWyR7bntP3x9fpf+HuzqDlia5OPhi1yo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721916859; c=relaxed/simple; bh=pYfPrTevNksawFDP7c9MLhZcWCVPxgbVMku1LRbHcOo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=IcVos2O88oRYXkJgxrWwkSooRhtGWjJ0MeDj28hss+CG70x1w5H9ZXaUctE8eIfKsBTYKbK+Xbyvh4dpFlbWRcQOz3l3tcC2nFH1g+3LTSFacf+HvYxxlYM69osmmVcC4SztnIZiUqaTyJcdbepJhpTL0WGBt9TlkDRfHvz9UmU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.client-ip=213.95.11.211 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id 7F9E768AFE; Thu, 25 Jul 2024 16:14:13 +0200 (CEST) Date: Thu, 25 Jul 2024 16:14:13 +0200 From: Christoph Hellwig To: Dave Chinner Cc: "Darrick J. Wong" , linux-xfs@vger.kernel.org, cem@kernel.org, Christoph Hellwig Subject: Re: [RFC] xfs: opting in or out of online repair Message-ID: <20240725141413.GA27725@lst.de> References: <20240724213852.GA612460@frogsfrogsfrogs> Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) On Thu, Jul 25, 2024 at 12:05:26PM +1000, Dave Chinner wrote: > Maybe I'm missing something important - this doesn't feel like > on-disk format stuff. Why would having online repair enabled make > the fileystem unmountable on older kernels? Yes, that's the downside of the feature flag. > Hmmm. Could this be implemented with an xattr on the root inode > that says "self healing allowed"? The annoying thing about stuff in the public file system namespace is that chowning the root of a file system to a random user isn't that uncommon, an that would give that user more privileges than intended. So it could not hust be a normal xattr but would have to be a privileged one, and with my VFS hat on I'd really like to avoid creating all these toally overloaded random non-user namespace xattrs that are a complete mess. One option would be an xattr on the metadir root (once we merge that, hopefully for 6.12). That would still require a new ioctl or whatever interface to change (or carve out an exception to the attr by handle interface), but it would not require kernel and tools to fully understand it. > > Note that administrator-initated scans (e.g. invoking xfs_scrub from the > > CLI) would not be blocked by this flag. > > > > Question: Should this compat flag control background scrubs as well? > > Probably. scrub is less intrusive, but I can see people wanting to > avoid it because it can have a perf impact. Could this be done with > a different xattr on the root inode? Yes, scrub vs repair should probably be separate.