Add move_tree()

This function is intended to be a more efficient way of moving trees
than shutil.move(). Specifically, it will use reflinks and btrfs
snapshots if possible to make copying more efficient.

diff --git a/mkosi/__init__.py b/mkosi/__init__.py
index 763c26c8fa6c5659451dfdfed93a40788b849a56..625b011c32d9c4817269049c4dc75e114b485328 100644 (file)
--- a/mkosi/__init__.py
+++ b/mkosi/__init__.py
@@ -42,7 +42,7 @@ from mkosi.qemu import copy_ephemeral, machine_cid, run_qemu
 from mkosi.remove import unlink_try_hard
 from mkosi.run import become_root, bwrap, chroot_cmd, init_mount_namespace, run, spawn
 from mkosi.state import MkosiState
-from mkosi.tree import copy_tree
+from mkosi.tree import copy_tree, move_tree
 from mkosi.types import PathString
 from mkosi.util import (
     InvokingUser,
@@ -804,7 +804,7 @@ def gen_kernel_modules_initrd(state: MkosiState, kver: str) -> Path:
         # this is not ideal since the compressed kernel modules will all be decompressed on boot which
         # requires significant memory.
         if state.config.distribution.is_apt_distribution():
-            maybe_compress(state, Compression.zst, kmods, kmods)
+            maybe_compress(state.config, Compression.zst, kmods, kmods)
 
     return kmods
 
@@ -998,10 +998,10 @@ def compressor_command(compression: Compression) -> list[PathString]:
         die(f"Unknown compression {compression}")
 
 
-def maybe_compress(state: MkosiState, compression: Compression, src: Path, dst: Optional[Path] = None) -> None:
+def maybe_compress(config: MkosiConfig, compression: Compression, src: Path, dst: Optional[Path] = None) -> None:
     if not compression or src.is_dir():
         if dst:
-            shutil.move(src, dst)
+            move_tree(config, src, dst)
         return
 
     if not dst:
@@ -1606,13 +1606,13 @@ def save_cache(state: MkosiState) -> None:
         # We only use the cache-overlay directory for caching if we have a base tree, otherwise we just
         # cache the root directory.
         if state.workspace.joinpath("cache-overlay").exists():
-            shutil.move(state.workspace / "cache-overlay", final)
+            move_tree(state.config, state.workspace / "cache-overlay", final)
         else:
-            shutil.move(state.root, final)
+            move_tree(state.config, state.root, final)
 
         if need_build_packages(state.config) and (state.workspace / "build-overlay").exists():
             unlink_try_hard(build)
-            shutil.move(state.workspace / "build-overlay", build)
+            move_tree(state.config, state.workspace / "build-overlay", build)
 
         manifest.write_text(json.dumps(state.config.cache_manifest()))
 
@@ -1744,7 +1744,7 @@ def make_image(state: MkosiState, skip: Sequence[str] = [], split: bool = False)
 
 def finalize_staging(state: MkosiState) -> None:
     for f in state.staging.iterdir():
-        shutil.move(f, state.config.output_dir)
+        move_tree(state.config, f, state.config.output_dir)
 
 
 def build_image(args: MkosiArgs, config: MkosiConfig) -> None:
@@ -1804,13 +1804,13 @@ def build_image(args: MkosiArgs, config: MkosiConfig) -> None:
         _, split_paths = make_image(state, split=True)
 
         for p in split_paths:
-            maybe_compress(state, state.config.compress_output, p)
+            maybe_compress(state.config, state.config.compress_output, p)
 
         make_tar(state)
         make_initrd(state)
         make_directory(state)
 
-        maybe_compress(state, state.config.compress_output,
+        maybe_compress(state.config, state.config.compress_output,
                        state.staging / state.config.output_with_format,
                        state.staging / state.config.output_with_compression)
 

diff --git a/mkosi/run.py b/mkosi/run.py
index 32783dc3259f576a42b2f0c7a2cb90152493b695..6a04eed7816a3f529d57976d47be07033b52c645 100644 (file)
--- a/mkosi/run.py
+++ b/mkosi/run.py
@@ -161,6 +161,7 @@ def run(
     user: Optional[int] = None,
     group: Optional[int] = None,
     env: Mapping[str, PathString] = {},
+    cwd: Optional[Path] = None,
     log: bool = True,
 ) -> CompletedProcess:
     if ARG_DEBUG.get():
@@ -200,6 +201,7 @@ def run(
             user=user,
             group=group,
             env=env,
+            cwd=cwd,
             preexec_fn=foreground,
         )
     except FileNotFoundError:

diff --git a/mkosi/tree.py b/mkosi/tree.py
index 8635bd51b575c4f0f55f713d9585e1c55b832ac0..aa2c5d4dccf4b3bde831a9a38478e83b40fe89ca 100644 (file)
--- a/mkosi/tree.py
+++ b/mkosi/tree.py
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: LGPL-2.1+
 
+import errno
 import shutil
 import subprocess
 from pathlib import Path
@@ -12,7 +13,7 @@ from mkosi.types import PathString
 
 
 def statfs(path: Path) -> str:
-    return cast(str, run(["stat", "--file-system", "--format", "%T", path.parent],
+    return cast(str, run(["stat", "--file-system", "--format", "%T", path],
                          stdout=subprocess.PIPE).stdout.strip())
 
 
@@ -76,3 +77,20 @@ def copy_tree(config: MkosiConfig, src: Path, dst: Path, *, preserve_owner: bool
 
     if result != 0:
         run(copy)
+
+
+def move_tree(config: MkosiConfig, src: Path, dst: Path) -> None:
+    if src == dst:
+        return
+
+    if dst.is_dir():
+        dst = dst / src.name
+
+    try:
+        src.rename(dst)
+    except OSError as e:
+        if e.errno != errno.EXDEV:
+            raise e
+
+        copy_tree(config, src, dst)
+        run(["rm", "-rf", src])