From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 777C435B152 for ; Thu, 23 Oct 2025 06:35:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761201303; cv=none; b=OXUey6OuM1+LkFFF9zuHNkK5fB3bNpVhJUdDWLD/ZLxTJjs4RTiLc2Bt6FQoj3kIjQ3nafP69F7LkgXjud12FAgrTPqOnk33AtMhzbry27nUw8eq6WbNcUN4nBEPPCkw7I9V89t2ltPgA3hA9whekQTMGlqeIPiGlmcVF3CGcjs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761201303; c=relaxed/simple; bh=WewLaNGkGfsC+Wm2yzMl17e1aHsq8lpqYVG0Hn4FpgM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=RW3rz2jVk97/47V7LNHNNHIGuzUd5lasbGQTRhyfQp3xjy/wvIJjtKM3OrtD4gxCUqgRtdJ2jRmQ3RBT0YKtzjvjhN3Ys5Gp6etKnOx0VsT/TtQ+P060uz1Y+TrULOFpmOL+3Oow3OT5TftzQH25TN/UQ+1nZMBIt+iYN1ASD8s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=aBSVNAOp; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="aBSVNAOp" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=g47RGF+NdJ09gYzALbAf2k1vxFGE900LwvdbO56igb8=; b=aBSVNAOpvUkqii5iq9D07my5Jy lpZfs7Hu421Tdfrq+zYldsfAc55mCYQokdcSimGj2LIszs2a9EBwAc/bPSZR7kjajy6jrtX7fatGp qoFYKu/qfIUhHjwIY/ImOPzcoJNsJTJ220M+iYvRxblVkqvjNBUd6wXvAokRtVh3tA07Qc8mJpzz9 nPPa9OLEo0bJ5C0YJ4GGIzwhHCgMLfIo/EcIKDozDBRHS7H4zd0BemdvZaimDQBcWZ5Dm45pIbdjI RYtT2qfe+XC+uEkWkndq/Z/1uGGhKcZWElFKvZsm6fnf7cMwT5LPuebM6HlWd+cyQjoAoTVyZqWY0 uqnRqYUw==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vBouZ-00000005E2m-2G17; Thu, 23 Oct 2025 06:34:59 +0000 Date: Wed, 22 Oct 2025 23:34:59 -0700 From: Christoph Hellwig To: "Darrick J. Wong" Cc: Christoph Hellwig , "Nirjhar Roy (IBM)" , linux-xfs@vger.kernel.org, ritesh.list@gmail.com, ojaswin@linux.ibm.com, bfoster@redhat.com, david@fromorbit.com, hsiangkao@linux.alibaba.com Subject: Re: [RFC V3 0/3] xfs: Add support to shrink multiple empty AGs Message-ID: References: <20251022160532.GM3356773@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: <20251022160532.GM3356773@frogsfrogsfrogs> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Wed, Oct 22, 2025 at 09:05:32AM -0700, Darrick J. Wong wrote: > > I'm still missing what the overall plan is here. For "normal" XFS > > setups you'll always have inodes that we can't migrate. Do you plan > > to use this with inode32 only? > > ...or resurrect xfs_reno? That only brings up some vague memories. But anything in userspace would not be transactional safe anyway. > > Data/attr extent migration might not be too hard if we can repurpose > xfs_zonegc for relocations. The zonegc code is very heavily dependent on not having to deal with freespace fragmentation for writes, so I don't think the code is directly reusable. But the overall idea applies, yes. > I think moving inodes is going to be very > very difficult because there's no way to atomically update all the > parents. > > (Not to mention whatever happens when the inumber abruptly changes) Yes. That's my big issues with all the shrink plans, what are we going to do about inodes?