On Mon, Oct 08, 2012 at 10:22:30PM +0100, Richard W.M. Jones wrote: > Adding sync() + fsync of each /dev/sd* device after the mkfs command > does appear to fix the problem. > > However it's a little bit difficult to know for sure because I might > just be changing the timing of things by adding these calls.
An update: Although doing the sync + fsync certainly makes the bug much much rarer, it does not entirely eliminate it. I have now seen one case where this still happened (log below). If there's anything else you'd like me to test, including kernel patches, just let me know. Rich. Extract from the full log at: http://kojipkgs.fedoraproject.org//work/tasks/7186/4577186/build.log modprobe btrfs [ 15.823412] Btrfs loaded grep ^[[:space:]]*btrfs$ /proc/filesystems mkfs.btrfs /dev/sda1 /dev/sdb1 [ 16.740868] device fsid 25aaca9b-0192-4cfd-a9eb-37fd222c2c8f devid 1 transid 1 /dev/sda1 [ 16.743227] device fsid 25aaca9b-0192-4cfd-a9eb-37fd222c2c8f devid 1 transid 1 /dev/sda1 [ 17.446334] device fsid 25aaca9b-0192-4cfd-a9eb-37fd222c2c8f devid 2 transid 3 /dev/sdb1 fsync /dev/sda fsync /dev/sdb fsync /dev/sdc fsync /dev/sdd libguestfs: recv_from_daemon: 40 bytes: 20 00 f5 f5 | 00 00 00 04 | 00 00 01 3d | 00 00 00 01 | 00 12 34 04 | ... libguestfs: trace: mkfs_btrfs = 0 libguestfs: trace: mount "/dev/sda1" "/" libguestfs: send_to_daemon: 68 bytes: 00 00 00 40 | 20 00 f5 f5 | 00 00 00 04 | 00 00 00 01 | 00 00 00 00 | ... guestfsd: main_loop: proc 317 (mkfs_btrfs) took 2.39 seconds guestfsd: main_loop: new request, len 0x40 mount -o /dev/sda1 /sysroot/ [ 17.838747] device fsid 25aaca9b-0192-4cfd-a9eb-37fd222c2c8f devid 2 transid 4 /dev/sdb1 [ 17.917277] device fsid 25aaca9b-0192-4cfd-a9eb-37fd222c2c8f devid 1 transid 4 /dev/sda1 [ 18.084520] device fsid 25aaca9b-0192-4cfd-a9eb-37fd222c2c8f devid 1 transid 4 /dev/sda1 [ 18.132447] device fsid 25aaca9b-0192-4cfd-a9eb-37fd222c2c8f devid 1 transid 4 /dev/sda1 [ 18.176566] btrfs: disk space caching is enabled [ 18.200901] btrfs bad tree block start 0 135168 [ 18.213456] btrfs: open_ctree failed mount: wrong fs type, bad option, bad superblock on /dev/sda1, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so guestfsd: error: /dev/sda1 on / (options: ''): mount: wrong fs type, bad option, bad superblock on /dev/sda1, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so libguestfs: recv_from_daemon: 284 bytes: 20 00 f5 f5 | 00 00 00 04 | 00 00 00 01 | 00 00 00 01 | 00 12 34 05 | ... libguestfs: trace: mount = -1 (error) -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://et.redhat.com/~rjones/virt-df/ -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
