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moby--moby/daemon/graphdriver/driver_linux.go
Kir Kolyshkin 17708e72a7 graphdriver: custom build-time priority list
Add a way to specify a custom graphdriver priority list
during build. This can be done with something like

  go build -ldflags "-X github.com/docker/docker/daemon/graphdriver.priority=overlay2,devicemapper"

As ldflags are already used by the engine build process, and it seems
that only one (last) `-ldflags` argument is taken into account by go,
an envoronment variable `DOCKER_LDFLAGS` is introduced in order to
be able to append some text to `-ldflags`. With this in place,
using the feature becomes

  make DOCKER_LDFLAGS="-X github.com/docker/docker/daemon/graphdriver.priority=overlay2,devicemapper" dynbinary

The idea behind this is, the priority list might be different
for different distros, so vendors are now able to change it
without patching the source code.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
2017-11-16 19:43:34 -08:00

128 lines
3.5 KiB
Go

// +build linux
package graphdriver
import (
"path/filepath"
"github.com/docker/docker/pkg/mount"
"golang.org/x/sys/unix"
)
const (
// FsMagicAufs filesystem id for Aufs
FsMagicAufs = FsMagic(0x61756673)
// FsMagicBtrfs filesystem id for Btrfs
FsMagicBtrfs = FsMagic(0x9123683E)
// FsMagicCramfs filesystem id for Cramfs
FsMagicCramfs = FsMagic(0x28cd3d45)
// FsMagicEcryptfs filesystem id for eCryptfs
FsMagicEcryptfs = FsMagic(0xf15f)
// FsMagicExtfs filesystem id for Extfs
FsMagicExtfs = FsMagic(0x0000EF53)
// FsMagicF2fs filesystem id for F2fs
FsMagicF2fs = FsMagic(0xF2F52010)
// FsMagicGPFS filesystem id for GPFS
FsMagicGPFS = FsMagic(0x47504653)
// FsMagicJffs2Fs filesystem if for Jffs2Fs
FsMagicJffs2Fs = FsMagic(0x000072b6)
// FsMagicJfs filesystem id for Jfs
FsMagicJfs = FsMagic(0x3153464a)
// FsMagicNfsFs filesystem id for NfsFs
FsMagicNfsFs = FsMagic(0x00006969)
// FsMagicRAMFs filesystem id for RamFs
FsMagicRAMFs = FsMagic(0x858458f6)
// FsMagicReiserFs filesystem id for ReiserFs
FsMagicReiserFs = FsMagic(0x52654973)
// FsMagicSmbFs filesystem id for SmbFs
FsMagicSmbFs = FsMagic(0x0000517B)
// FsMagicSquashFs filesystem id for SquashFs
FsMagicSquashFs = FsMagic(0x73717368)
// FsMagicTmpFs filesystem id for TmpFs
FsMagicTmpFs = FsMagic(0x01021994)
// FsMagicVxFS filesystem id for VxFs
FsMagicVxFS = FsMagic(0xa501fcf5)
// FsMagicXfs filesystem id for Xfs
FsMagicXfs = FsMagic(0x58465342)
// FsMagicZfs filesystem id for Zfs
FsMagicZfs = FsMagic(0x2fc12fc1)
// FsMagicOverlay filesystem id for overlay
FsMagicOverlay = FsMagic(0x794C7630)
)
var (
// List of drivers that should be used in an order
priority = "btrfs,zfs,overlay2,aufs,overlay,devicemapper,vfs"
// FsNames maps filesystem id to name of the filesystem.
FsNames = map[FsMagic]string{
FsMagicAufs: "aufs",
FsMagicBtrfs: "btrfs",
FsMagicCramfs: "cramfs",
FsMagicEcryptfs: "ecryptfs",
FsMagicExtfs: "extfs",
FsMagicF2fs: "f2fs",
FsMagicGPFS: "gpfs",
FsMagicJffs2Fs: "jffs2",
FsMagicJfs: "jfs",
FsMagicNfsFs: "nfs",
FsMagicOverlay: "overlayfs",
FsMagicRAMFs: "ramfs",
FsMagicReiserFs: "reiserfs",
FsMagicSmbFs: "smb",
FsMagicSquashFs: "squashfs",
FsMagicTmpFs: "tmpfs",
FsMagicUnsupported: "unsupported",
FsMagicVxFS: "vxfs",
FsMagicXfs: "xfs",
FsMagicZfs: "zfs",
}
)
// GetFSMagic returns the filesystem id given the path.
func GetFSMagic(rootpath string) (FsMagic, error) {
var buf unix.Statfs_t
if err := unix.Statfs(filepath.Dir(rootpath), &buf); err != nil {
return 0, err
}
return FsMagic(buf.Type), nil
}
// NewFsChecker returns a checker configured for the provided FsMagic
func NewFsChecker(t FsMagic) Checker {
return &fsChecker{
t: t,
}
}
type fsChecker struct {
t FsMagic
}
func (c *fsChecker) IsMounted(path string) bool {
m, _ := Mounted(c.t, path)
return m
}
// NewDefaultChecker returns a check that parses /proc/mountinfo to check
// if the specified path is mounted.
func NewDefaultChecker() Checker {
return &defaultChecker{}
}
type defaultChecker struct {
}
func (c *defaultChecker) IsMounted(path string) bool {
m, _ := mount.Mounted(path)
return m
}
// Mounted checks if the given path is mounted as the fs type
func Mounted(fsType FsMagic, mountPath string) (bool, error) {
var buf unix.Statfs_t
if err := unix.Statfs(mountPath, &buf); err != nil {
return false, err
}
return FsMagic(buf.Type) == fsType, nil
}