** Changed in: cloud-utils
Status: In Progress => Fix Committed
** Description changed:
The changes recently added to mount-image-callback under bug 1493188
that were targeted at supporting 'overlay' filesystem type while still
supporting 'overlayfs' may result in exiting with "unsupported" when a
mount would work.
The changes basically said:
- if overlay in /proc/filesystems:
- return GOOD
- modprobe --quiet --use-blacklist overlay
- if overlay in /proc/filesystems:
- return GOOD
- return BAD
+ if overlay in /proc/filesystems:
+ return GOOD
+ modprobe --quiet --use-blacklist overlay
+ if overlay in /proc/filesystems:
+ return GOOD
+ return BAD
the path that fails now that previously succeeded is when 'modprobe'
would not work, but 'mount -t overlay' *would*. This occurs in build
systems where the running kernel is of one version and code is running
in a chroot that does not have access to the kernel modules in
/lib/modules/.
'mount -t overlay' works in this scenario because the mount abi call passes
the filesystem type 'overlay', and the kernel then does:
- fs/filesystems.c: if (!fs && (request_module("fs-%.*s", len, name)
== 0))
+ fs/filesystems.c: if (!fs && (request_module("fs-%.*s", len, name)
== 0))
The kernel's scope is not chrooted, so the module gets loaded and
everything is happy.
+
+ The new changes are to instead basically do:
+ for fstype in overlay overlayfs; do
+ mount -t $fstype <options> && return GOOD
+ if /proc/filesystems is readable and $fstype in /proc/filesystems; then
+ return FAIL
+ fi
+ done
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https://bugs.launchpad.net/bugs/1630274
Title:
mount-image-callback may not mount overlay when it could
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