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d5dbbb5369
The daemon uses a priority list to automatically select the best-matching storage driver for the backing filesystem that is used. Historically, overlay2 was not supported on Btrfs and ZFS, and the daemon would automatically pick the `btrfs` or `zfs` storage driver if that was the Backing File System. Commits649e4c8889ande226aea280improved our detection to check if overlay2 was supported on the backing file- system, allowing overlay2 to be used on top of Btrfs or ZFS, but did not change the priority list. While both Btrfs and ZFS have advantages for certain use-cases, and provide advanced features that are not available to overlay2, they also are known to require more "handholding", and are generally considered to be mostly useful for "advanced" users. This patch changes the storage-driver priority list, to prefer overlay2 (if supported by the backing filesystem), and effectively makes btrfs and zfs opt-in storage drivers. This change does not affect existing installations; the daemon will detect the storage driver that was previously in use (based on the presence of storage directories in `/var/lib/docker`). Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
130 lines
3.7 KiB
Go
130 lines
3.7 KiB
Go
package graphdriver // import "github.com/docker/docker/daemon/graphdriver"
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import (
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"github.com/moby/sys/mountinfo"
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"golang.org/x/sys/unix"
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)
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const (
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// FsMagicAufs filesystem id for Aufs
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FsMagicAufs = FsMagic(0x61756673)
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// FsMagicBtrfs filesystem id for Btrfs
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FsMagicBtrfs = FsMagic(0x9123683E)
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// FsMagicCramfs filesystem id for Cramfs
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FsMagicCramfs = FsMagic(0x28cd3d45)
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// FsMagicEcryptfs filesystem id for eCryptfs
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FsMagicEcryptfs = FsMagic(0xf15f)
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// FsMagicExtfs filesystem id for Extfs
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FsMagicExtfs = FsMagic(0x0000EF53)
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// FsMagicF2fs filesystem id for F2fs
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FsMagicF2fs = FsMagic(0xF2F52010)
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// FsMagicGPFS filesystem id for GPFS
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FsMagicGPFS = FsMagic(0x47504653)
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// FsMagicJffs2Fs filesystem if for Jffs2Fs
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FsMagicJffs2Fs = FsMagic(0x000072b6)
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// FsMagicJfs filesystem id for Jfs
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FsMagicJfs = FsMagic(0x3153464a)
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// FsMagicNfsFs filesystem id for NfsFs
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FsMagicNfsFs = FsMagic(0x00006969)
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// FsMagicRAMFs filesystem id for RamFs
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FsMagicRAMFs = FsMagic(0x858458f6)
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// FsMagicReiserFs filesystem id for ReiserFs
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FsMagicReiserFs = FsMagic(0x52654973)
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// FsMagicSmbFs filesystem id for SmbFs
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FsMagicSmbFs = FsMagic(0x0000517B)
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// FsMagicSquashFs filesystem id for SquashFs
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FsMagicSquashFs = FsMagic(0x73717368)
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// FsMagicTmpFs filesystem id for TmpFs
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FsMagicTmpFs = FsMagic(0x01021994)
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// FsMagicVxFS filesystem id for VxFs
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FsMagicVxFS = FsMagic(0xa501fcf5)
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// FsMagicXfs filesystem id for Xfs
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FsMagicXfs = FsMagic(0x58465342)
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// FsMagicZfs filesystem id for Zfs
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FsMagicZfs = FsMagic(0x2fc12fc1)
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// FsMagicOverlay filesystem id for overlay
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FsMagicOverlay = FsMagic(0x794C7630)
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// FsMagicFUSE filesystem id for FUSE
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FsMagicFUSE = FsMagic(0x65735546)
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)
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var (
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// List of drivers that should be used in an order
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priority = "overlay2,fuse-overlayfs,btrfs,zfs,aufs,overlay,devicemapper,vfs"
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// FsNames maps filesystem id to name of the filesystem.
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FsNames = map[FsMagic]string{
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FsMagicAufs: "aufs",
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FsMagicBtrfs: "btrfs",
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FsMagicCramfs: "cramfs",
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FsMagicEcryptfs: "ecryptfs",
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FsMagicExtfs: "extfs",
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FsMagicF2fs: "f2fs",
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FsMagicFUSE: "fuse",
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FsMagicGPFS: "gpfs",
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FsMagicJffs2Fs: "jffs2",
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FsMagicJfs: "jfs",
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FsMagicNfsFs: "nfs",
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FsMagicOverlay: "overlayfs",
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FsMagicRAMFs: "ramfs",
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FsMagicReiserFs: "reiserfs",
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FsMagicSmbFs: "smb",
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FsMagicSquashFs: "squashfs",
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FsMagicTmpFs: "tmpfs",
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FsMagicUnsupported: "unsupported",
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FsMagicVxFS: "vxfs",
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FsMagicXfs: "xfs",
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FsMagicZfs: "zfs",
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}
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)
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// GetFSMagic returns the filesystem id given the path.
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func GetFSMagic(rootpath string) (FsMagic, error) {
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var buf unix.Statfs_t
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if err := unix.Statfs(rootpath, &buf); err != nil {
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return 0, err
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}
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return FsMagic(buf.Type), nil
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}
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// NewFsChecker returns a checker configured for the provided FsMagic
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func NewFsChecker(t FsMagic) Checker {
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return &fsChecker{
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t: t,
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}
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}
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type fsChecker struct {
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t FsMagic
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}
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func (c *fsChecker) IsMounted(path string) bool {
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m, _ := Mounted(c.t, path)
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return m
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}
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// NewDefaultChecker returns a check that parses /proc/mountinfo to check
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// if the specified path is mounted.
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func NewDefaultChecker() Checker {
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return &defaultChecker{}
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}
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type defaultChecker struct {
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}
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func (c *defaultChecker) IsMounted(path string) bool {
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m, _ := mountinfo.Mounted(path)
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return m
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}
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// Mounted checks if the given path is mounted as the fs type
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func Mounted(fsType FsMagic, mountPath string) (bool, error) {
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var buf unix.Statfs_t
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if err := unix.Statfs(mountPath, &buf); err != nil {
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if err == unix.ENOENT { // not exist, thus not mounted
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err = nil
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}
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return false, err
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}
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return FsMagic(buf.Type) == fsType, nil
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}
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