Red Hat Bugzilla – Bug 615389
Output of "mount" is missing mapping displays for loop-mounts
Last modified: 2011-05-19 10:05:45 EDT
The output of "mount" does not display the mapping of <source image> to
<mountpoint> directly in RHEL 6, where RHEL 5 used to display it. E.g.
# mount -o loop,ro /mnt/tmp/rhel/6.0beta2/x86_64/RHEL6.0-20100622.1-Server-x86_64-DVD1.iso /mnt/loop/
RHEL 5.2 (util-linux-2.13-0.47.el5):
# mount | grep iso
/mnt/tmp/rhel/6.0beta2/x86_64/RHEL6.0-20100622.1-Server-x86_64-DVD1.iso on /mnt/loop type iso9660 (ro,loop=/dev/loop0)
RHEL 6 (util-linux-ng-2.17.2-1.el6.x86_64):
# mount | grep iso
/dev/loop0 on /mnt/loop type iso9660 (ro)
Therefore the needed information has to be determined manually, e.g. via
# losetup /dev/loop0
/dev/loop0: :1519 (/mnt/tmp/rhel/6.0beta2/x86_64/RHEL6.0-20100622.1-Server-x86_64*)
Please adapt "mount" to resolve the mappings directly again.
This issue has been proposed when we are only considering blocker
issues in the current Red Hat Enterprise Linux release. It has
been denied for the current Red Hat Enterprise Linux release.
** If you would still like this issue considered for the current
release, ask your support representative to file as a blocker on
your behalf. Otherwise ask that it be considered for the next
Red Hat Enterprise Linux release. **
The Linux kernel (since 2.6.25) supports auto-clear flag for mount
devices. All loop devices with this flag are automatically destroyed
when the device is unmounted. The auto-clear flag allows to remove loop=
mount option from /etc/mtab.
Our long-term goal is to remove /etc/mtab from Linux (and use
/proc/self/mountinfo only), so we want to minimize number of userspace
specific mount options.
We can revert the auto-clear support in RHEL6 mount(8), but it's not optimal
solution from long-term point of view.
The final solution is to improve losetup(8) to return full path to the
backing file (now the filename is restricted to 64 bytes in
LOOP_GET_STATUS ioctl (the ideal solution is to have the filename in /sys)).
Side effect of this bug is that "mount -a" can mount the same image file twice -- for more details see bug #618957
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.