[pve-devel] [PATCH ct/common] mount point hotplugging & new mount api

[Wolfgang Bumiller]

On Tue, Nov 12, 2019 at 03:09:27PM +0100, Oguz Bektas wrote:
> hi,
> 
> built the latest git version of pve-common and pve-container with
> wolfgang's patches.
> 
> with running kernel: 5.0.21-4-pve
> and the latest pve-kernel-5.3
> 
> found a small issue while testing.
> 
> when one has an older kernel and tries to hotplug a mountpoint
> 
> -----------------------------------------------
> Parameter verification failed. (400)
> 
> mp1: unable to hotplug mp1: Can't use an undefined value as a symbol
> reference at /usr/share/perl5/PVE/LXC.pm line 1670. 
> -----------------------------------------------
> 
> and around this line is:
> 
> -----------------------------------------------
> 
>         PVE::Tools::move_mount(
>             fileno($mount_fd),
>             "",
>             &AT_FDCWD,
>             $mp->{mp},
>             &MOVE_MOUNT_F_EMPTY_PATH, # line 1670
>         );
>     });
> }
> 
> -----------------------------------------------
> 
> so i'm guessing since that syscall doesn't exist in older kernels,
> we get an undefined value.
> 
> it would be better to handle this error with something more
> user-friendly and verbose.
> 
> i'm still testing and will write here if i notice something else.

Right, forgot to add the kernel check there. The whole function
shouldn't be executed on older kernels.