storaged: filter podman btrfs subvolumes

Podman btrfs subvolumes are an implementation detail of podman and not
interesting for a Cockpit user in the storage page.

Closes: #20912

pkg/storaged/client.js

@@ -248,12 +248,18 @@ export async function btrfs_poll() {
  for (const line of output.split("\n")) {
  const m = line.match(/ID (\d+).*parent (\d+).*parent_uuid (.*)uuid (.*) path (<FS_TREE>\/)?(.*)/);
  if (m) {
+ const pathname = m[6];
+ // Ignore podman btrfs subvolumes, they are an implementation detail.
+ if (pathname.includes("containers/storage/btrfs/subvolumes")) {
+ continue;
+ }
+
  // The parent uuid is the uuid of which this subvolume is a snapshot.
  // https://github.com/torvalds/linux/blob/8d025e2092e29bfd13e56c78e22af25fac83c8ec/include/uapi/linux/btrfs.h#L885
  let parent_uuid = m[3].trim();
  // BTRFS_UUID_SIZE is 16
  parent_uuid = parent_uuid.length < 16 ? null : parent_uuid;
- subvols.push({ pathname: m[6], id: Number(m[1]), parent: Number(m[2]), uuid: m[4], parent_uuid });
+ subvols.push({ pathname, id: Number(m[1]), parent: Number(m[2]), uuid: m[4], parent_uuid });
  }
  }
  uuids_subvols[uuid] = subvols;

test/verify/check-storage-btrfs

@@ -99,6 +99,21 @@ class TestStorageBtrfs(storagelib.StorageCase):
  b.go("#/")
  b.wait_visible(self.card("Storage"))
 
+ # podman subvolumes are hidden, Cockpit hides everything matching "containers/storage/btrfs/subvolumes"
+ m.execute(f"""
+ mkdir -p /run/kitchen/containers/storage/btrfs/subvolumes
+ btrfs subvolume create /run/kitchen/containers/storage/btrfs/subvolumes/containername
+
+ mkdir -p /run/kitchen/.local/share/containers/storage/btrfs/subvolumes
+ btrfs subvolume create /run/kitchen/.local/share/containers/storage/btrfs/subvolumes/grafana
+
+ btrfs subvolume create {subvol_mount_point}/pancake
+ """)
+
+ b.wait_in_text(self.card_row("Storage", name="pancake"), "btrfs subvolume")
+ b.wait_not_in_text("div[data-test-card-title='Storage']", "containername")
+ b.wait_not_in_text("div[data-test-card-title='Storage']", "grafana")
+
  # mount outside of fstab, should be cleaned up when re-formatting
  m.execute(f"""
  btrfs subvolume create {mount_point}/nonfstab