[pve-devel] [PATCH v2 storage] btrfs: check for btrfs in on_add_hook and activate

[pve-devel] [PATCH v2 storage] btrfs: check for btrfs in on_add_hook and activate

[Wolfgang Bumiller]

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
---
Changes to v1:
  * Fabian's feedback:
    * removed on_add_hook since activate_storage is called anyway
    * moved btrfs check to after the DirPlugin checks

 PVE/Storage/BTRFSPlugin.pm | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/PVE/Storage/BTRFSPlugin.pm b/PVE/Storage/BTRFSPlugin.pm
index 133edc6..dc5894a 100644
--- a/PVE/Storage/BTRFSPlugin.pm
+++ b/PVE/Storage/BTRFSPlugin.pm
@@ -20,6 +20,7 @@ use constant {
     FS_NOCOW_FL => 0x00800000,
     FS_IOC_GETFLAGS => 0x40086602,
     FS_IOC_SETFLAGS => 0x80086601,
+    BTRFS_MAGIC => 0x9123683e,
 };
 
 # Configuration (similar to DirPlugin)
@@ -89,9 +90,30 @@ sub check_config {
     return PVE::Storage::DirPlugin::check_config($self, $sectionId, $config, $create, $skipSchemaCheck);
 }
 
+my sub getfsmagic($) {
+    my ($path) = @_;
+    # The field type sizes in `struct statfs` are defined in a rather annoying way, and we only
+    # need the first field, which is a `long` for our supported platforms.
+    # Should be moved to pve-rs, so this can be the problem of the `libc` crate ;-)
+    # Just round up and extract what we need:
+    my $buf = pack('x160');
+    if (0 != syscall(&PVE::Syscall::SYS_statfs, $path, $buf)) {
+	die "statfs on '$path' failed - $!\n";
+    }
+
+    return unpack('L!', $buf);
+}
+
+my sub assert_btrfs($) {
+    my ($path) = @_;
+    die "'$path' is not a btrfs file system\n"
+	if getfsmagic($path) != BTRFS_MAGIC;
+}
+
 sub activate_storage {
     my ($class, $storeid, $scfg, $cache) = @_;
-    return PVE::Storage::DirPlugin::activate_storage($class, $storeid, $scfg, $cache);
+    PVE::Storage::DirPlugin::activate_storage($class, $storeid, $scfg, $cache);
+    assert_btrfs($scfg->{path});
 }
 
 sub status {
-- 
2.30.2

[pve-devel] applied: [PATCH v2 storage] btrfs: check for btrfs in on_add_hook and activate

[Thomas Lamprecht]

On 24.06.21 10:45, Wolfgang Bumiller wrote:
> Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
> ---
> Changes to v1:
>   * Fabian's feedback:
>     * removed on_add_hook since activate_storage is called anyway
>     * moved btrfs check to after the DirPlugin checks
> 
>  PVE/Storage/BTRFSPlugin.pm | 24 +++++++++++++++++++++++-
>  1 file changed, 23 insertions(+), 1 deletion(-)
> 
>

applied, thanks! I made a follow-up on top to avoid leaving over sub-directories
form the DirPlugin::activate_storage call in the case that assert_btrfs fails.


----8<----
diff --git a/PVE/Storage/BTRFSPlugin.pm b/PVE/Storage/BTRFSPlugin.pm
index dc5894a..5360dca 100644
--- a/PVE/Storage/BTRFSPlugin.pm
+++ b/PVE/Storage/BTRFSPlugin.pm
@@ -112,8 +112,21 @@ my sub assert_btrfs($) {
 
 sub activate_storage {
     my ($class, $storeid, $scfg, $cache) = @_;
-    PVE::Storage::DirPlugin::activate_storage($class, $storeid, $scfg, $cache);
-    assert_btrfs($scfg->{path});
+
+    my $path = $scfg->{path};
+    if (!defined($scfg->{mkdir}) || $scfg->{mkdir}) {
+       mkpath $path;
+    }
+
+    my $mp = PVE::Storage::DirPlugin::parse_is_mountpoint($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: '$mp'\n";
+    }
+
+    assert_btrfs($path); # only assert this stuff now, ensures $path is there and better UX
+
+    $class->SUPER::activate_storage($storeid, $scfg, $cache);
 }
 
 sub status {