Re: [pve-devel] [PATCH storage] fix 3214: DirPlugin: die early if mountpoint not mounted

[Aaron Lauterer <a.lauterer@proxmox.com>]

On 12/22/20 2:39 PM, Wolfgang Bumiller wrote:
> Here our `mkdir` meaning is `create the path to the storage`.
> 
> I'd propose the following:
> 
> Apply neither #3214 patch. Keep the `mkdir` code as it is. Deprecate the
> `mkdir` option and split it up into 2 new options:
> 
> `create_path` and `populate_directory`
> 
> It should be harder to confuse those two in the future (plus they can
> both be set explicitly simultaneously).

sounds good!

> 
> On Tue, Dec 22, 2020 at 01:18:52PM +0100, Aaron Lauterer wrote:
>> If the `is_mountpoint` option is enabled, it is sensible to first check
>> for the mountpoint before proceeding any further in the storage
>> activation.
>>
>> The old behaviour would create the path to the mountpoint if the `mdkir`
>> option wasn't set to false. This resulted in mountpoints further up
>> the path to not mount anymore, e.g. nested ZFS datasets.
>>
>> Signed-off-by: Aaron Lauterer <a.lauterer@proxmox.com>
>> ---
>>
>> There is another patch[0] already for this bug report but it deals with
>> a related, but different problem of not creating the internal storage
>> directory structure if `mkdir 0` was set.
>>
>> [0] https://lists.proxmox.com/pipermail/pve-devel/2020-December/046572.html
>>
>>   PVE/Storage/DirPlugin.pm | 10 +++++-----
>>   1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/PVE/Storage/DirPlugin.pm b/PVE/Storage/DirPlugin.pm
>> index 2267f11..81aaf2b 100644
>> --- a/PVE/Storage/DirPlugin.pm
>> +++ b/PVE/Storage/DirPlugin.pm
>> @@ -132,17 +132,17 @@ sub status {
>>   sub activate_storage {
>>       my ($class, $storeid, $scfg, $cache) = @_;
>>   
>> -    my $path = $scfg->{path};
>> -    if (!defined($scfg->{mkdir}) || $scfg->{mkdir}) {
>> -	mkpath $path;
>> -    }
> 
> Depending on whether we want to also "fix" the defaults (`mkdir` not
> present meaning it is not *used*, rather than it is `on`), the above
> should either happen `if !defined($scfg->{create_path})` (not explicitly
> using `create_path`), or changed to `if ($scfg->{mkdir})` (which should
> generate a warning).

AFAIU this sounds like a breaking change and should probably only be done on a major version release. If we actually want to change that.

> 
>> -
>>       my $mp = parse_is_mountpoint($scfg);
>>       if (defined($mp) && !path_is_mounted($mp, $cache->{mountdata})) {
>>   	die "unable to activate storage '$storeid' - " .
>>   	    "directory is expected to be a mount point but is not mounted: '$mp'\n";
>>       }
>>   
> 
> the `is_mountpoint` check would stay here after `mkdir` handling for
> legacy behavior.
> and below here is where we'd add the hunk below with
> `s/mkdir/populate_directory/`;
> 
> The other patch would do use `populate_directory` if it is explicitly
> set, otherwise fall through to the old `mkdir` based code with a
> warning that `populate_directory` should be explicitly set in the
> config.
> 
> 
>> +    my $path = $scfg->{path};
>> +    if (!defined($scfg->{mkdir}) || $scfg->{mkdir}) {
>> +	mkpath $path;
>> +    }
>> +
>>       $class->SUPER::activate_storage($storeid, $scfg, $cache);
>>   }
>>   
>> -- 
>> 2.20.1