[pve-devel] [PATCH storage 1/1] fix #3580: plugins: make preallocation mode selectable for qcow2 and raw images

[alexandre derumier]

Hi,
it can be done too with ceph rbd with "rbd create ... –thick-provision"

Le lundi 06 septembre 2021 à 15:15 +0200, Lorenz Stechauner a écrit :
> the plugins for file based storages
>  * BTRFS
>  * CIFS
>  * Dir
>  * Glusterfs
>  * NFS
> now allow the option 'preallocation'.
> 
> 'preallocation' can have four values:
>  * default
>  * off
>  * metadata
>  * falloc
>  * full
> see man pages for `qemu-img` for what these mean exactly. [0]
> 
> the defualt value was chosen to be
>  * qcow2: metadata (as previously)
>  * raw: off (I was unable to find any documentation on this, so
>     could only test this and found, that 'off' was the most
>     fitting.)
> 
> when using 'metadata' as preallocation mode, for raw images 'off'
> is used.
> 
> [0]
> https://qemu.readthedocs.io/en/latest/system/images.html#disk-image-file-formats
> 
> Signed-off-by: Lorenz Stechauner <l.stechauner at proxmox.com>
> ---
>  PVE/Storage/BTRFSPlugin.pm     |  1 +
>  PVE/Storage/CIFSPlugin.pm      |  1 +
>  PVE/Storage/DirPlugin.pm       |  1 +
>  PVE/Storage/GlusterfsPlugin.pm |  4 ++-
>  PVE/Storage/NFSPlugin.pm       |  1 +
>  PVE/Storage/Plugin.pm          | 46
> +++++++++++++++++++++++++++++++++-
>  6 files changed, 52 insertions(+), 2 deletions(-)
> 
> diff --git a/PVE/Storage/BTRFSPlugin.pm b/PVE/Storage/BTRFSPlugin.pm
> index fe42082..31a2954 100644
> --- a/PVE/Storage/BTRFSPlugin.pm
> +++ b/PVE/Storage/BTRFSPlugin.pm
> @@ -73,6 +73,7 @@ sub options {
>         is_mountpoint => { optional => 1 },
>         nocow => { optional => 1 },
>         mkdir => { optional => 1 },
> +       preallocation => { optional => 1 },
>         # TODO: The new variant of mkdir with  `populate` vs
> `create`...
>      };
>  }
> diff --git a/PVE/Storage/CIFSPlugin.pm b/PVE/Storage/CIFSPlugin.pm
> index 0221069..2d94413 100644
> --- a/PVE/Storage/CIFSPlugin.pm
> +++ b/PVE/Storage/CIFSPlugin.pm
> @@ -140,6 +140,7 @@ sub options {
>         smbversion => { optional => 1},
>         mkdir => { optional => 1 },
>         bwlimit => { optional => 1 },
> +       preallocation => { optional => 1 },
>      };
>  }
>  
> diff --git a/PVE/Storage/DirPlugin.pm b/PVE/Storage/DirPlugin.pm
> index 2267f11..3eeec98 100644
> --- a/PVE/Storage/DirPlugin.pm
> +++ b/PVE/Storage/DirPlugin.pm
> @@ -59,6 +59,7 @@ sub options {
>         mkdir => { optional => 1 },
>         is_mountpoint => { optional => 1 },
>         bwlimit => { optional => 1 },
> +       preallocation => { optional => 1 },
>     };
>  }
>  
> diff --git a/PVE/Storage/GlusterfsPlugin.pm
> b/PVE/Storage/GlusterfsPlugin.pm
> index ea4df82..d8d2b88 100644
> --- a/PVE/Storage/GlusterfsPlugin.pm
> +++ b/PVE/Storage/GlusterfsPlugin.pm
> @@ -137,6 +137,7 @@ sub options {
>         format => { optional => 1 },
>         mkdir => { optional => 1 },
>         bwlimit => { optional => 1 },
> +       preallocation => { optional => 1 },
>      };
>  }
>  
> @@ -260,7 +261,8 @@ sub alloc_image {
>  
>      my $cmd = ['/usr/bin/qemu-img', 'create'];
>  
> -    push @$cmd, '-o', 'preallocation=metadata' if $fmt eq 'qcow2';
> +    my $prealloc_opt =
> PVE::Storage::Plugin::preallocation_cmd_option($scfg, $fmt);
> +    push @$cmd, '-o', $prealloc_opt if defined($prealloc_opt);
>  
>      push @$cmd, '-f', $fmt, $volumepath, "${size}K";
>  
> diff --git a/PVE/Storage/NFSPlugin.pm b/PVE/Storage/NFSPlugin.pm
> index 39bf15a..21b288a 100644
> --- a/PVE/Storage/NFSPlugin.pm
> +++ b/PVE/Storage/NFSPlugin.pm
> @@ -90,6 +90,7 @@ sub options {
>         format => { optional => 1 },
>         mkdir => { optional => 1 },
>         bwlimit => { optional => 1 },
> +       preallocation => { optional => 1 },
>      };
>  }
>  
> diff --git a/PVE/Storage/Plugin.pm b/PVE/Storage/Plugin.pm
> index b1865cb..4924525 100644
> --- a/PVE/Storage/Plugin.pm
> +++ b/PVE/Storage/Plugin.pm
> @@ -41,6 +41,19 @@ our @SHARED_STORAGE = (
>      'pbs',
>  );
>  
> +our $QCOW2_PREALLOCATION = {
> +    off => 1,
> +    metadata => 1,
> +    falloc => 1,
> +    full => 1,
> +};
> +
> +our $RAW_PREALLOCATION = {
> +    off => 1,
> +    falloc => 1,
> +    full => 1,
> +};
> +
>  our $MAX_VOLUMES_PER_GUEST = 1024;
>  
>  cfs_register_file ('storage.cfg',
> @@ -150,6 +163,11 @@ my $defaultData = {
>             type => 'string', format => 'pve-storage-format',
>             optional => 1,
>         },
> +       preallocation => {
> +           description => "Preallocation mode for raw and qcow2
> images.",
> +           type => 'string', enum => ['default', 'off', 'metadata',
> 'falloc', 'full'],
> +           optional => 1,
> +       },
>      },
>  };
>  
> @@ -762,7 +780,8 @@ sub alloc_image {
>      } else {
>         my $cmd = ['/usr/bin/qemu-img', 'create'];
>  
> -       push @$cmd, '-o', 'preallocation=metadata' if $fmt eq
> 'qcow2';
> +       my $prealloc_opt = preallocation_cmd_option($scfg, $fmt);
> +       push @$cmd, '-o', $prealloc_opt if defined($prealloc_opt);
>  
>         push @$cmd, '-f', $fmt, $path, "${size}K";
>  
> @@ -1484,4 +1503,29 @@ sub volume_import_formats {
>      return ();
>  }
>  
> +sub preallocation_cmd_option {
> +    my ($scfg, $fmt) = @_;
> +
> +    my $prealloc = $scfg->{preallocation};
> +
> +    $prealloc = undef if $prealloc eq 'default';
> +
> +    if ($fmt eq 'qcow2') {
> +       $prealloc = $prealloc // 'metadata';
> +
> +       die "preallocation mode '$prealloc' not supported by format
> '$fmt'\n" if !$QCOW2_PREALLOCATION->{$prealloc};
> +
> +       return "preallocation=$prealloc";
> +    } elsif ($fmt eq 'raw') {
> +       $prealloc = $prealloc // 'off';
> +       $prealloc = 'off' if $prealloc eq 'metadata';
> +
> +       die "preallocation mode '$prealloc' not supported by format
> '$fmt'\n" if !$RAW_PREALLOCATION->{$prealloc};
> +
> +       return "preallocation=$prealloc";
> +    }
> +
> +    return undef;
> +}
> +
>  1;