composefs: add pre-flight disk space check for native backend

The previous commit (7196079) added a pre-flight disk space check for
the ostree and ostree+unified-storage backend paths. This commit extends
the same protection to the native composefs backend.

- Rename check_disk_space_composefs -> check_disk_space_unified for the
  ostree unified-storage path (uses PreparedImportMeta), to clarify that
  this variant is not used by the native composefs backend.

- Add check_disk_space_composefs for the native composefs backend: sums
  layer sizes from the raw ImageManifest and calls fstatvfs on the
  composefs objects directory to verify available space before pulling.

- Call check_disk_space_composefs in do_upgrade() (covers bootc upgrade
  and bootc switch on the native composefs backend), reusing the
  already-opened composefs repo from booted_cfs.repo.

- Call check_disk_space_composefs in install_to_filesystem_impl() before
  initialize_composefs_repository() (covers bootc install --composefs-backend).
  Note: ensure_composefs_dir() is called first to create the objects
  directory if it does not yet exist on the fresh install target.

- Enable the existing pre-flight disk check tmt test for the composefs
  backend (remove fixme_skip_if_composefs).

Note: the check uses compressed layer sizes from the manifest, which is
a lower bound of actual disk usage (composefs stores decompressed
content). This is consistent with the ostree path and the broader
container ecosystem, as uncompressed sizes are not available in the OCI
manifest without downloading layers.

Assisted-by: AI
Signed-off-by: Wei Shi <wshi@redhat.com>

Author: shi2wei3

crates/lib/src/bootc_composefs/update.rs

@@ -255,6 +255,13 @@ pub(crate) async fn do_upgrade(
 ) -> Result<()> {
     start_finalize_stated_svc()?;
 
+    // Pre-flight disk space check before pulling any data.
+    crate::deploy::check_disk_space_composefs(
+        &booted_cfs.repo,
+        &img_manifest_config.manifest,
+        imgref,
+    )?;
+
     let (repo, entries, id, fs) = pull_composefs_repo(
         &imgref.transport,
         &imgref.image,

crates/lib/src/deploy.rs

@@ -411,15 +411,31 @@ pub(crate) fn check_disk_space_ostree(
     )
 }
 
-/// Verify there is sufficient disk space to pull an image into the composefs store.
-pub(crate) fn check_disk_space_composefs(
+/// Verify there is sufficient disk space to pull an image into the composefs store
+/// via the ostree unified-storage path (uses `PreparedImportMeta`).
+pub(crate) fn check_disk_space_unified(
     cfs: &crate::store::ComposefsRepository,
     image_meta: &PreparedImportMeta,
     imgref: &ImageReference,
 ) -> Result<()> {
     check_disk_space_inner(cfs.objects_dir()?, image_meta.bytes_to_fetch, 0, imgref)
 }
 
+/// Verify there is sufficient disk space to pull an image into the composefs store
+/// for the native composefs backend (uses a raw `ImageManifest`).
+pub(crate) fn check_disk_space_composefs(
+    cfs: &crate::store::ComposefsRepository,
+    manifest: &ostree_ext::oci_spec::image::ImageManifest,
+    imgref: &ImageReference,
+) -> Result<()> {
+    let bytes_to_fetch: u64 = manifest
+        .layers()
+        .iter()
+        .map(|l: &ostree_ext::oci_spec::image::Descriptor| l.size())
+        .sum();
+    check_disk_space_inner(cfs.objects_dir()?, bytes_to_fetch, 0, imgref)
+}
+
 pub(crate) struct PreparedImportMeta {
     pub imp: ImageImporter,
     pub prep: Box<PreparedImport>,
@@ -609,7 +625,7 @@ pub(crate) async fn pull_unified(
             Ok(existing)
         }
         PreparedPullResult::Ready(prepared_image_meta) => {
-            check_disk_space_composefs(
+            check_disk_space_unified(
                 store.get_ensure_composefs()?.as_ref(),
                 &prepared_image_meta,
                 imgref,

crates/lib/src/install.rs

@@ -188,7 +188,11 @@ use serde::{Deserialize, Serialize};
 #[cfg(feature = "install-to-disk")]
 use self::baseline::InstallBlockDeviceOpts;
 use crate::bootc_composefs::status::ComposefsCmdline;
-use crate::bootc_composefs::{boot::setup_composefs_boot, repo::initialize_composefs_repository};
+use crate::bootc_composefs::{
+    boot::setup_composefs_boot,
+    repo::{get_imgref, initialize_composefs_repository, open_composefs_repo},
+    status::get_container_manifest_and_config,
+};
 use crate::boundimage::{BoundImage, ResolvedBoundImage};
 use crate::containerenv::ContainerExecutionInfo;
 use crate::deploy::{MergeState, PreparedPullResult, prepare_for_pull, pull_from_prepared};
@@ -1951,8 +1955,23 @@ async fn install_to_filesystem_impl(
     }
 
     if state.composefs_options.composefs_backend {
-        // Load a fd for the mounted target physical root
-
+        // Pre-flight disk space check for native composefs install path.
+        {
+            let imgref = &state.source.imageref;
+            let imgref_repr = get_imgref(&imgref.transport.to_string(), &imgref.name);
+            let img_manifest_config = get_container_manifest_and_config(&imgref_repr).await?;
+            crate::store::ensure_composefs_dir(&rootfs.physical_root)?;
+            let cfs_repo = open_composefs_repo(&rootfs.physical_root)?;
+            crate::deploy::check_disk_space_composefs(
+                &cfs_repo,
+                &img_manifest_config.manifest,
+                &crate::spec::ImageReference {
+                    image: imgref.name.clone(),
+                    transport: imgref.transport.to_string(),
+                    signature: None,
+                },
+            )?;
+        }
         let pull_result = initialize_composefs_repository(
             state,
             rootfs,

tmt/plans/integration.fmf

@@ -201,7 +201,6 @@ execute:
     how: fmf
     test:
       - /tmt/tests/tests/test-35-upgrade-preflight-disk-check
-  extra-fixme_skip_if_composefs: true
 
 /plan-36-rollback:
   summary: Test bootc rollback functionality

tmt/tests/booted/test-upgrade-preflight-disk-check.nu

@@ -2,8 +2,6 @@
 # tmt:
 #   summary: Verify pre-flight disk space check rejects images with inflated layer sizes
 #   duration: 10m
-# extra:
-#   fixme_skip_if_composefs: true
 #
 # This test does NOT require a reboot.
 # It constructs a minimal fake OCI image directory that claims to have an