Merge pull request #44776 from thaJeztah/23.0_backport_btrfs_uapi

[23.0 backport] graphdriver/btrfs: depend on kernel UAPI instead of libbtrfs

Dockerfile

@@ -537,7 +537,6 @@ RUN --mount=type=cache,sharing=locked,id=moby-dev-aptlib,target=/var/lib/apt \
             pkg-config \
             dpkg-dev \
             libapparmor-dev \
-            libbtrfs-dev \
             libdevmapper-dev \
             libseccomp-dev \
             libsecret-1-dev \
@@ -556,7 +555,6 @@ RUN --mount=type=cache,sharing=locked,id=moby-build-aptlib,target=/var/lib/apt \
         xx-apt-get install --no-install-recommends -y \
             gcc \
             libapparmor-dev \
-            libbtrfs-dev \
             libc6-dev \
             libdevmapper-dev \
             libseccomp-dev \

Dockerfile.e2e

@@ -4,7 +4,6 @@ FROM golang:${GO_VERSION}-alpine AS base
 ENV GO111MODULE=off
 RUN apk --no-cache add \
     bash \
-    btrfs-progs-dev \
     build-base \
     curl \
     lvm2-dev \

Dockerfile.simple

@@ -24,10 +24,8 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 		build-essential \
 		curl \
 		cmake \
-		gcc \
 		git \
 		libapparmor-dev \
-		libbtrfs-dev \
 		libdevmapper-dev \
 		libseccomp-dev \
 		ca-certificates \

daemon/graphdriver/aufs/aufs.go

@@ -32,6 +32,7 @@ import (
 	"os/exec"
 	"path"
 	"path/filepath"
+	"strconv"
 	"strings"
 	"sync"
 
@@ -209,8 +210,8 @@ func (a *Driver) Status() [][2]string {
 	return [][2]string{
 		{"Root Dir", a.rootPath()},
 		{"Backing Filesystem", backingFs},
-		{"Dirs", fmt.Sprintf("%d", len(ids))},
-		{"Dirperm1 Supported", fmt.Sprintf("%v", useDirperm())},
+		{"Dirs", strconv.Itoa(len(ids))},
+		{"Dirperm1 Supported", strconv.FormatBool(useDirperm())},
 	}
 }
 

daemon/graphdriver/aufs/aufs_test.go

@@ -10,6 +10,7 @@ import (
 	"os"
 	"path"
 	"path/filepath"
+	"strconv"
 	"sync"
 	"testing"
 
@@ -659,8 +660,8 @@ func testMountMoreThan42Layers(t *testing.T, mountPath string) {
 	for i := 1; i < 127; i++ {
 		expected++
 		var (
-			parent  = fmt.Sprintf("%d", i-1)
-			current = fmt.Sprintf("%d", i)
+			parent  = strconv.Itoa(i - 1)
+			current = strconv.Itoa(i)
 		)
 
 		if parent == "0" {

daemon/graphdriver/btrfs/btrfs.go

@@ -5,12 +5,17 @@ package btrfs // import "github.com/docker/docker/daemon/graphdriver/btrfs"
 
 /*
 #include <stdlib.h>
+#include <stdio.h>
 #include <dirent.h>
 
-// keep struct field name compatible with btrfs-progs < 6.1.
-#define max_referenced max_rfer
-#include <btrfs/ioctl.h>
-#include <btrfs/ctree.h>
+#include <linux/version.h>
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,12,0)
+    #error "Headers from kernel >= 4.12 are required to build with Btrfs support."
+    #error "HINT: Set 'DOCKER_BUILDTAGS=exclude_graphdriver_btrfs' to build without Btrfs."
+#endif
+
+#include <linux/btrfs.h>
+#include <linux/btrfs_tree.h>
 
 static void set_name_btrfs_ioctl_vol_args_v2(struct btrfs_ioctl_vol_args_v2* btrfs_struct, const char* value) {
     snprintf(btrfs_struct->name, BTRFS_SUBVOL_NAME_MAX, "%s", value);
@@ -150,18 +155,11 @@ func (d *Driver) String() string {
 	return "btrfs"
 }
 
-// Status returns current driver information in a two dimensional string array.
-// Output contains "Build Version" and "Library Version" of the btrfs libraries used.
-// Version information can be used to check compatibility with your kernel.
+// Status returns the status of the driver.
 func (d *Driver) Status() [][2]string {
-	status := [][2]string{}
-	if bv := btrfsBuildVersion(); bv != "-" {
-		status = append(status, [2]string{"Build Version", bv})
+	return [][2]string{
+		{"Btrfs", ""},
 	}
-	if lv := btrfsLibVersion(); lv != -1 {
-		status = append(status, [2]string{"Library Version", fmt.Sprintf("%d", lv)})
-	}
-	return status
 }
 
 // GetMetadata returns empty metadata for this driver.
@@ -241,7 +239,7 @@ func subvolSnapshot(src, dest, name string) error {
 
 	var cs = C.CString(name)
 	C.set_name_btrfs_ioctl_vol_args_v2(&args, cs)
-	C.free(unsafe.Pointer(cs))
+	free(cs)
 
 	_, _, errno := unix.Syscall(unix.SYS_IOCTL, getDirFd(destDir), C.BTRFS_IOC_SNAP_CREATE_V2,
 		uintptr(unsafe.Pointer(&args)))

daemon/graphdriver/btrfs/version.go

@@ -1,27 +0,0 @@
-//go:build linux
-// +build linux
-
-package btrfs // import "github.com/docker/docker/daemon/graphdriver/btrfs"
-
-/*
-#include <btrfs/version.h>
-
-// around version 3.16, they did not define lib version yet
-#ifndef BTRFS_LIB_VERSION
-#define BTRFS_LIB_VERSION -1
-#endif
-
-// upstream had removed it, but now it will be coming back
-#ifndef BTRFS_BUILD_VERSION
-#define BTRFS_BUILD_VERSION "-"
-#endif
-*/
-import "C"
-
-func btrfsBuildVersion() string {
-	return string(C.BTRFS_BUILD_VERSION)
-}
-
-func btrfsLibVersion() int {
-	return int(C.BTRFS_LIB_VERSION)
-}

daemon/graphdriver/btrfs/version_test.go

@@ -1,14 +0,0 @@
-//go:build linux
-// +build linux
-
-package btrfs // import "github.com/docker/docker/daemon/graphdriver/btrfs"
-
-import (
-	"testing"
-)
-
-func TestLibVersion(t *testing.T) {
-	if btrfsLibVersion() <= 0 {
-		t.Error("expected output from btrfs lib version > 0")
-	}
-}

daemon/graphdriver/zfs/zfs.go

@@ -232,7 +232,7 @@ func (d *Driver) GetMetadata(id string) (map[string]string, error) {
 }
 
 func (d *Driver) cloneFilesystem(name, parentName string) error {
-	snapshotName := fmt.Sprintf("%d", time.Now().Nanosecond())
+	snapshotName := strconv.Itoa(time.Now().Nanosecond())
 	parentDataset := zfs.Dataset{Name: parentName}
 	snapshot, err := parentDataset.Snapshot(snapshotName /*recursive */, false)
 	if err != nil {

project/PACKAGERS.md

@@ -139,7 +139,7 @@ by having support for them in the kernel or userspace. A few examples include:
 
 * AUFS graph driver (requires AUFS patches/support enabled in the kernel, and at
   least the "auplink" utility from aufs-tools)
-* BTRFS graph driver (requires BTRFS support enabled in the kernel)
+* BTRFS graph driver (requires suitable kernel headers: `linux/btrfs.h` and `linux/btrfs_tree.h`, present in 4.12+; and BTRFS support enabled in the kernel)
 * ZFS graph driver (requires userspace zfs-utils and a corresponding kernel module)
 * Libseccomp to allow running seccomp profiles with containers