composefs: Pass physical_root down instead of accessing global /sysroot

Refactor `get_sysroot_parent_dev()` to accept a `physical_root: &Dir`
parameter instead of hardcoding access to `/sysroot`. This continues
the ongoing work to eliminate global state access in the composefs
backend, following the same pattern as the recent BootedComposefs
and BootedOstree refactoring.

The function now uses `inspect_filesystem_of_dir()` which operates
on a Dir fd.

All callers updated to pass `&storage.physical_root` or open a Dir
for the upgrade code paths. Helper functions like `list_bootloader_entries()`
and `delete_depl_boot_entries()` also updated to accept and pass down
the physical_root parameter.

Assisted-by: Claude Code (Sonnet 4.5)
Signed-off-by: Colin Walters <[email protected]>

Author: cgwalters

crates/lib/src/bootc_composefs/boot.rs

@@ -5,7 +5,7 @@ use std::path::Path;
 
 use anyhow::{anyhow, Context, Result};
 use bootc_blockdev::find_parent_devices;
-use bootc_mount::inspect_filesystem;
+use bootc_mount::inspect_filesystem_of_dir;
 use bootc_mount::tempmount::TempMount;
 use camino::{Utf8Path, Utf8PathBuf};
 use cap_std_ext::{
@@ -37,7 +37,10 @@ use crate::composefs_consts::{TYPE1_ENT_PATH, TYPE1_ENT_PATH_STAGED};
 use crate::parsers::bls_config::{BLSConfig, BLSConfigType};
 use crate::parsers::grub_menuconfig::MenuEntry;
 use crate::task::Task;
-use crate::{bootc_composefs::repo::open_composefs_repo, store::ComposefsFilesystem};
+use crate::{
+    bootc_composefs::repo::open_composefs_repo,
+    store::{ComposefsFilesystem, Storage},
+};
 use crate::{
     bootc_composefs::state::{get_booted_bls, write_composefs_state},
     bootloader::esp_in,
@@ -76,7 +79,7 @@ pub(crate) enum BootSetupType<'a> {
     /// For initial setup, i.e. install to-disk
     Setup((&'a RootSetup, &'a State, &'a ComposefsFilesystem)),
     /// For `bootc upgrade`
-    Upgrade((&'a ComposefsFilesystem, &'a Host)),
+    Upgrade((&'a Storage, &'a ComposefsFilesystem, &'a Host)),
 }
 
 #[derive(
@@ -168,14 +171,12 @@ pub fn mount_esp(device: &str) -> Result<TempMount> {
     TempMount::mount_dev(device, "vfat", flags, Some(c"fmask=0177,dmask=0077"))
 }
 
-pub fn get_sysroot_parent_dev() -> Result<String> {
-    let sysroot = Utf8PathBuf::from("/sysroot");
-
-    let fsinfo = inspect_filesystem(&sysroot)?;
+pub fn get_sysroot_parent_dev(physical_root: &Dir) -> Result<String> {
+    let fsinfo = inspect_filesystem_of_dir(physical_root)?;
     let parent_devices = find_parent_devices(&fsinfo.source)?;
 
     let Some(parent) = parent_devices.into_iter().next() else {
-        anyhow::bail!("Could not find parent device for mountpoint /sysroot");
+        anyhow::bail!("Could not find parent device of system root");
     };
 
     Ok(parent)
@@ -399,8 +400,8 @@ pub(crate) fn setup_composefs_bls_boot(
             )
         }
 
-        BootSetupType::Upgrade((fs, host)) => {
-            let sysroot_parent = get_sysroot_parent_dev()?;
+        BootSetupType::Upgrade((storage, fs, host)) => {
+            let sysroot_parent = get_sysroot_parent_dev(&storage.physical_root)?;
             let bootloader = host.require_composefs_booted()?.bootloader.clone();
 
             (
@@ -872,9 +873,9 @@ pub(crate) fn setup_composefs_uki_boot(
             )
         }
 
-        BootSetupType::Upgrade((_, host)) => {
-            let sysroot = Utf8PathBuf::from("/sysroot");
-            let sysroot_parent = get_sysroot_parent_dev()?;
+        BootSetupType::Upgrade((storage, _, host)) => {
+            let sysroot = Utf8PathBuf::from("/sysroot"); // Still needed for root_path
+            let sysroot_parent = get_sysroot_parent_dev(&storage.physical_root)?;
             let bootloader = host.require_composefs_booted()?.bootloader.clone();
 
             (

crates/lib/src/bootc_composefs/delete.rs

@@ -1,10 +1,7 @@
 use std::{collections::HashSet, io::Write, path::Path};
 
 use anyhow::{Context, Result};
-use cap_std_ext::{
-    cap_std::{ambient_authority, fs::Dir},
-    dirext::CapStdExtDirExt,
-};
+use cap_std_ext::{cap_std::fs::Dir, dirext::CapStdExtDirExt};
 use composefs::fsverity::Sha512HashValue;
 use composefs_boot::bootloader::{EFI_ADDON_DIR_EXT, EFI_EXT};
 
@@ -216,17 +213,20 @@ fn remove_grub_menucfg_entry(id: &str, boot_dir: &Dir, deleting_staged: bool) ->
 }
 
 #[fn_error_context::context("Deleting boot entries for deployment {}", deployment.deployment.verity)]
-fn delete_depl_boot_entries(deployment: &DeploymentEntry, deleting_staged: bool) -> Result<()> {
+fn delete_depl_boot_entries(
+    deployment: &DeploymentEntry,
+    physical_root: &Dir,
+    deleting_staged: bool,
+) -> Result<()> {
     match deployment.deployment.bootloader {
         Bootloader::Grub => {
-            let boot_dir = Dir::open_ambient_dir("/sysroot/boot", ambient_authority())
-                .context("Opening boot dir")?;
+            let boot_dir = physical_root.open_dir("boot").context("Opening boot dir")?;
 
             match deployment.deployment.boot_type {
                 BootType::Bls => delete_type1_entry(deployment, &boot_dir, deleting_staged),
 
                 BootType::Uki => {
-                    let device = get_sysroot_parent_dev()?;
+                    let device = get_sysroot_parent_dev(physical_root)?;
                     let (esp_part, ..) = get_esp_partition(&device)?;
                     let esp_mount = mount_esp(&esp_part)?;
 
@@ -242,7 +242,7 @@ fn delete_depl_boot_entries(deployment: &DeploymentEntry, deleting_staged: bool)
         }
 
         Bootloader::Systemd => {
-            let device = get_sysroot_parent_dev()?;
+            let device = get_sysroot_parent_dev(physical_root)?;
             let (esp_part, ..) = get_esp_partition(&device)?;
 
             let esp_mount = mount_esp(&esp_part)?;
@@ -362,7 +362,7 @@ pub(crate) async fn delete_composefs_deployment(
 
     tracing::info!("Deleting {kind}deployment '{deployment_id}'");
 
-    delete_depl_boot_entries(&depl_to_del, deleting_staged)?;
+    delete_depl_boot_entries(&depl_to_del, &storage.physical_root, deleting_staged)?;
 
     composefs_gc(storage, booted_cfs).await?;
 

crates/lib/src/bootc_composefs/finalize.rs

@@ -86,7 +86,7 @@ pub(crate) async fn composefs_backend_finalize(
     // Unmount EROFS
     drop(erofs_tmp_mnt);
 
-    let sysroot_parent = get_sysroot_parent_dev()?;
+    let sysroot_parent = get_sysroot_parent_dev(&storage.physical_root)?;
     // NOTE: Assumption here that ESP will always be present
     let (esp_part, ..) = get_esp_partition(&sysroot_parent)?;
 

crates/lib/src/bootc_composefs/gc.rs

@@ -5,10 +5,7 @@
 //! - We delete bootloader + image but fail to delete the state/unrefenced objects etc
 
 use anyhow::{Context, Result};
-use cap_std_ext::{
-    cap_std::{ambient_authority, fs::Dir},
-    dirext::CapStdExtDirExt,
-};
+use cap_std_ext::{cap_std::fs::Dir, dirext::CapStdExtDirExt};
 use composefs::fsverity::{FsVerityHashValue, Sha512HashValue};
 
 use crate::{
@@ -47,13 +44,12 @@ fn list_erofs_images(sysroot: &Dir) -> Result<Vec<String>> {
 /// # Returns
 /// The fsverity of EROFS images corresponding to boot entries
 #[fn_error_context::context("Listing bootloader entries")]
-fn list_bootloader_entries() -> Result<Vec<String>> {
+fn list_bootloader_entries(physical_root: &Dir) -> Result<Vec<String>> {
     let bootloader = get_bootloader()?;
 
     let entries = match bootloader {
         Bootloader::Grub => {
-            let boot_dir = Dir::open_ambient_dir("/sysroot/boot", ambient_authority())
-                .context("Opening boot dir")?;
+            let boot_dir = physical_root.open_dir("boot").context("Opening boot dir")?;
 
             // Grub entries are always in boot
             let grub_dir = boot_dir.open_dir("grub2").context("Opening grub dir")?;
@@ -79,7 +75,7 @@ fn list_bootloader_entries() -> Result<Vec<String>> {
         }
 
         Bootloader::Systemd => {
-            let device = get_sysroot_parent_dev()?;
+            let device = get_sysroot_parent_dev(physical_root)?;
             let (esp_part, ..) = get_esp_partition(&device)?;
             let esp_mount = mount_esp(&esp_part)?;
 
@@ -179,7 +175,7 @@ pub(crate) async fn composefs_gc(storage: &Storage, booted_cfs: &BootedComposefs
 
     let sysroot = &storage.physical_root;
 
-    let bootloader_entries = list_bootloader_entries()?;
+    let bootloader_entries = list_bootloader_entries(&storage.physical_root)?;
     let images = list_erofs_images(&sysroot)?;
 
     // Collect the deployments that have an image but no bootloader entry

crates/lib/src/bootc_composefs/rollback.rs

@@ -215,7 +215,7 @@ pub(crate) async fn composefs_rollback(
         }
 
         Bootloader::Systemd => {
-            let parent = get_sysroot_parent_dev()?;
+            let parent = get_sysroot_parent_dev(&storage.physical_root)?;
             let (esp_part, ..) = get_esp_partition(&parent)?;
             let esp_mount = mount_esp(&esp_part)?;
 

crates/lib/src/bootc_composefs/status.rs

@@ -355,7 +355,7 @@ pub(crate) async fn composefs_deployment_status_from(
         //
         // See: https://uapi-group.org/specifications/specs/boot_loader_specification/#mount-points
         Bootloader::Systemd => {
-            let parent = get_sysroot_parent_dev()?;
+            let parent = get_sysroot_parent_dev(sysroot)?;
             let (esp_part, ..) = get_esp_partition(&parent)?;
 
             let esp_mount = mount_esp(&esp_part)?;

crates/lib/src/bootc_composefs/switch.rs

@@ -57,15 +57,18 @@ pub(crate) async fn switch_composefs(
     match boot_type {
         BootType::Bls => {
             boot_digest = Some(setup_composefs_bls_boot(
-                BootSetupType::Upgrade((&fs, &host)),
+                BootSetupType::Upgrade((storage, &fs, &host)),
                 repo,
                 &id,
                 entry,
             )?)
         }
-        BootType::Uki => {
-            setup_composefs_uki_boot(BootSetupType::Upgrade((&fs, &host)), repo, &id, entries)?
-        }
+        BootType::Uki => setup_composefs_uki_boot(
+            BootSetupType::Upgrade((storage, &fs, &host)),
+            repo,
+            &id,
+            entries,
+        )?,
     };
 
     // TODO: Remove this hardcoded path when write_composefs_state accepts a Dir

crates/lib/src/bootc_composefs/update.rs

@@ -160,16 +160,19 @@ pub(crate) async fn upgrade_composefs(
     match boot_type {
         BootType::Bls => {
             boot_digest = Some(setup_composefs_bls_boot(
-                BootSetupType::Upgrade((&fs, &host)),
+                BootSetupType::Upgrade((storage, &fs, &host)),
                 repo,
                 &id,
                 entry,
             )?)
         }
 
-        BootType::Uki => {
-            setup_composefs_uki_boot(BootSetupType::Upgrade((&fs, &host)), repo, &id, entries)?
-        }
+        BootType::Uki => setup_composefs_uki_boot(
+            BootSetupType::Upgrade((storage, &fs, &host)),
+            repo,
+            &id,
+            entries,
+        )?,
     };
 
     write_composefs_state(

crates/system-reinstall-bootc/src/btrfs.rs

@@ -4,7 +4,7 @@ use fn_error_context::context;
 
 #[context("check_root_siblings")]
 pub(crate) fn check_root_siblings() -> Result<Vec<String>> {
-    let mounts = bootc_mount::run_findmnt(&[], None)?;
+    let mounts = bootc_mount::run_findmnt(&[], None, None)?;
     let problem_filesystems: Vec<String> = mounts
         .filesystems
         .iter()

crates/system-reinstall-bootc/src/lvm.rs

@@ -57,7 +57,7 @@ pub(crate) fn check_root_siblings() -> Result<Vec<String>> {
     let siblings: Vec<String> = all_volumes
         .iter()
         .filter(|lv| {
-            let mount = run_findmnt(&["-S", &lv.lv_path], None).log_err_default();
+            let mount = run_findmnt(&["-S", &lv.lv_path], None, None).log_err_default();
             if let Some(fs) = mount.filesystems.first() {
                 &fs.target == "/"
             } else {
@@ -66,7 +66,7 @@ pub(crate) fn check_root_siblings() -> Result<Vec<String>> {
         })
         .flat_map(|root_lv| parse_volumes(Some(root_lv.vg_name.as_str())).unwrap_or_default())
         .try_fold(Vec::new(), |mut acc, r| -> anyhow::Result<_> {
-            let mount = run_findmnt(&["-S", &r.lv_path], None).log_err_default();
+            let mount = run_findmnt(&["-S", &r.lv_path], None, None).log_err_default();
             let mount_path = if let Some(fs) = mount.filesystems.first() {
                 &fs.target
             } else {