On Tue, Nov 20, 2012 at 02:52:46PM +0100, Karel Zak wrote: > On Tue, Nov 20, 2012 at 12:16:34PM +0100, Karel Zak wrote: > > On Mon, Nov 19, 2012 at 03:41:16PM +0000, Richard W.M. Jones wrote: > > > This change adds the --force option which, when used, undoes the above > > > flag change. However you still have to use --force most of the time > > > when erasing something that isn't a plain unmounted filesystem. > > > > I'll improve the code. It's stupid disadvantage that --force is > > necessary for things like partitions tables. We have to use > > O_EXCL more carefully. > > ... it seems that this is unnecessary. It's possible to delete > partition table (open with O_EXCL) if any of the partitions is not > mounted. It seems that only mount(2) has any impact to O_EXCL. > > I guess that --force is enough. Sorry, that was my mistake. My initial report had a simplifying assumption that wasn't correct. In fact the problem case is where you try to wipe a device which contains a volume groups and a logical volume; note the LVs don't contain filesystems, and nothing is mounted. A simple reproducer is: $ guestfish -N lv wipefs /dev/sda libguestfs: error: wipefs: wipefs: error: /dev/sda: probing initialization failed: Device or resource busy Adding -x shows what's going on: $ guestfish -N lv wipefs /dev/sda -x libguestfs: trace: set_pgroup true libguestfs: trace: set_pgroup = 0 libguestfs: trace: add_drive "test1.img" libguestfs: trace: add_drive = 0 libguestfs: trace: is_config libguestfs: trace: is_config = 1 libguestfs: trace: launch libguestfs: trace: get_tmpdir libguestfs: trace: get_tmpdir = "/tmp" libguestfs: trace: get_cachedir libguestfs: trace: get_cachedir = "/var/tmp" libguestfs: trace: disk_format "/home/rjones/test1.img" libguestfs: trace: disk_format = "raw" libguestfs: trace: get_cachedir libguestfs: trace: get_cachedir = "/var/tmp" libguestfs: trace: launch = 0 libguestfs: trace: part_disk "/dev/sda" "mbr" libguestfs: trace: part_disk = 0 libguestfs: trace: pvcreate "/dev/sda1" libguestfs: trace: pvcreate = 0 libguestfs: trace: vgcreate "VG" "/dev/sda1" libguestfs: trace: vgcreate = 0 libguestfs: trace: lvcreate_free "LV" "VG" 100 libguestfs: trace: lvcreate_free = 0 libguestfs: trace: wipefs "/dev/sda" libguestfs: trace: wipefs = -1 (error) libguestfs: error: wipefs: wipefs: error: /dev/sda: probing initialization failed: Device or resource busy libguestfs: trace: close libguestfs: trace: internal_autosync libguestfs: trace: internal_autosync = 0 Use -v to get more details. I don't want to claim this is a bug, but it is certainly a change in behaviour, and we want the --force option in libguestfs so we can say "just do it". By the way: Just a partition + a PV: wipefs doesn't need to be forced. guestfish -N part pvcreate /dev/sda1 : wipefs /dev/sda Just a partition + a PV + a VG: wipefs doesn't need to be forced. guestfish -N part pvcreate /dev/sda1 : vgcreate VG /dev/sda1 : wipefs /dev/sda Partition + PV + VG + LV (but no filesystem): wipefs needs --force. [for example see above] Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming blog: http://rwmj.wordpress.com Fedora now supports 80 OCaml packages (the OPEN alternative to F#) http://cocan.org/getting_started_with_ocaml_on_red_hat_and_fedora -- To unsubscribe from this list: send the line "unsubscribe util-linux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
