From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ravi Pinjala Subject: Mounting multiple regular files as a filesystem Date: Mon, 15 Jun 2009 00:36:22 -0500 Message-ID: <4A35DDD6.9020307@p-static.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 To: linux-btrfs@vger.kernel.org Return-path: List-ID: I'm trying to create a multi-device filesystem on top of regular files (not actual disks), and mount that to a loopback device. For a filesystem created on a single file, it works fine, but for a filesystem across multiple files, it doesn't. dd if=/dev/zero of=img1 bs=4096 count=65536 dd if=/dev/zero of=img2 bs=4096 count=65536 dd if=/dev/zero of=img3 bs=4096 count=65536 dd if=/dev/zero of=img4 bs=4096 count=65536 mkfs.btrfs img1 mount -o loop -t btrfs img1 /mnt/test # works mkfs.btrfs img1 img2 img3 img4 mount -o loop -t btrfs img1 /mnt/test # fails When I try to mount with multiple files, it also prints a message to syslog: Jun 15 00:32:10 3vil device fsid a147d6b950f66dca-3e2e7f52011c93b0 devid 4 transid 9 /dev/loop/0 Jun 15 00:32:10 3vil btrfs: failed to read chunk tree on loop0 Jun 15 00:32:10 3vil btrfs: open_ctree failed Am I doing something wrong, or is this use case broken right now? --Ravi