btrfs: cloning with subvolumes (fix permission issues)

Author: williamstein

src/packages/file-server/btrfs/subvolume-snapshots.ts

@@ -27,7 +27,7 @@ export class SubvolumeSnapshots {
       return;
     }
     await this.subvolume.fs.mkdir(SNAPSHOTS);
-    await this.subvolume.fs.chmod(SNAPSHOTS, "0555");
+    await this.subvolume.fs.chmod(SNAPSHOTS, "0550");
   };
 
   create = async (name?: string) => {

src/packages/file-server/btrfs/subvolumes.ts

@@ -5,7 +5,7 @@ import { SNAPSHOTS } from "./subvolume-snapshots";
 import { exists } from "@cocalc/backend/misc/async-utils-node";
 import { join, normalize } from "path";
 import { btrfs } from "./util";
-import { rename, readdir, rm, stat } from "fs/promises";
+import { chmod, rename, readdir, rm, stat } from "fs/promises";
 import { executeCode } from "@cocalc/backend/execute-code";
 
 const RESERVED = new Set(["bup", SNAPSHOTS]);
@@ -48,14 +48,11 @@ export class Subvolumes {
     );
     const snapdir = join(this.filesystem.opts.mount, dest, SNAPSHOTS);
     if (await exists(snapdir)) {
-      const snapshots = await readdir(snapdir);
-      const f = async (x) => {
-        await rm(join(this.filesystem.opts.mount, dest, SNAPSHOTS, x), {
-          recursive: true,
-          force: true,
-        });
-      };
-      await Promise.all(snapshots.map(f));
+      await chmod(snapdir, "0700");
+      await rm(snapdir, {
+        recursive: true,
+        force: true,
+      });
     }
     const src = await this.get(source);
     const dst = await this.get(dest);

src/packages/file-server/btrfs/test/filesystem.test.ts

@@ -83,4 +83,23 @@ describe("operations with subvolumes", () => {
   });
 });
 
+describe("clone of a subvolume with snapshots should have no snapshots", () => {
+  it("creates a subvolume, a file, and a snapshot", async () => {
+    const x = await fs.subvolumes.get("my-volume");
+    await x.fs.writeFile("abc.txt", "hi");
+    await x.snapshots.create("my-snap");
+  });
+
+  it("clones my-volume", async () => {
+    await fs.subvolumes.clone("my-volume", "my-clone");
+  });
+
+  it("clone has no snapshots", async () => {
+    const clone = await fs.subvolumes.get("my-clone");
+    expect(await clone.fs.readFile("abc.txt", "utf8")).toEqual("hi");
+    expect(await clone.snapshots.ls()).toEqual([]);
+    await clone.snapshots.create("my-clone-snap");
+  });
+});
+
 afterAll(after);

src/packages/file-server/btrfs/test/subvolume.test.ts

@@ -125,11 +125,11 @@ describe("the filesystem operations", () => {
 
   it("make a file readonly, then change it back", async () => {
     await vol.fs.writeFile("c.txt", "hi");
-    await vol.fs.chmod("c.txt", "444");
+    await vol.fs.chmod("c.txt", "440");
     expect(async () => {
       await vol.fs.appendFile("c.txt", " there");
     }).rejects.toThrow("EACCES");
-    await vol.fs.chmod("c.txt", "666");
+    await vol.fs.chmod("c.txt", "660");
     await vol.fs.appendFile("c.txt", " there");
   });