From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([59.151.112.132]:8404 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1755989AbaCLBKG (ORCPT ); Tue, 11 Mar 2014 21:10:06 -0400 From: "quwenruo@cn.fujitsu.com" To: Zach Brown , Saul Wold CC: "linux-btrfs@vger.kernel.org" , "dg77.kim@samsung.com" Subject: Re: Building a brtfs filesystem < 70M? Date: Wed, 12 Mar 2014 01:10:04 +0000 Message-ID: <531FB42C.5000101@cn.fujitsu.com> References: <531E4A02.5010404@linux.intel.com> <20140311163700.GQ2069@lenny.home.zabbo.net> In-Reply-To: <20140311163700.GQ2069@lenny.home.zabbo.net> Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Tue, 11 Mar 2014 09:37:00 -0700, Zach Brown wrote: >> There seems to be an issue if we try to build a btrfs based FS that >> is less than 70M, we get the following assertion failure: >> >> mkfs.btrfs: extent-tree.c:2682: btrfs_reserve_extent: Assertion >> `!(ret)' failed. >> mkfs.btrfs -b 104857600 -r rootfs rootfs.btrfs > Honestly, the path of least resistance is probably to avoid the -r > option all together. As you've found, it's not reliable. > > I'd take the time to roll the infrastrcture to populate the image by > writing to a mounted image with the kernel code. > > - z > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > I although agree with the mount + cp(kernel) way to populate the filesystem. Also I think the implement of "-r" should be somewhat like mount+cp other than the current way, since the userland implement is noticeably slow than kernel way. Cc:Donggeun Kim I also wonder why "-r" option is needed, since IMO the "-r" options is only needed if the filesystem is full readonly and must be populated on initialization like squashfs. And since btrfs is a filesystem that can be read and write, the "-r" option is not somewhat needed. So I prefer to remove the "-r" option. Thanks Qu{.n++%ݶw{.n+{k~^nrzh&zzޗ++zfh~iz_j:+v)ߣm