DockerCLI/vendor/github.com/moby/sys/mount/mount_unix.go

89 lines
2.6 KiB
Go

//go:build !darwin && !windows
// +build !darwin,!windows
package mount
import (
"fmt"
"sort"
"github.com/moby/sys/mountinfo"
"golang.org/x/sys/unix"
)
// Mount will mount filesystem according to the specified configuration.
// Options must be specified like the mount or fstab unix commands:
// "opt1=val1,opt2=val2". See flags.go for supported option flags.
func Mount(device, target, mType, options string) error {
flag, data := parseOptions(options)
return mount(device, target, mType, uintptr(flag), data)
}
// Unmount lazily unmounts a filesystem on supported platforms, otherwise does
// a normal unmount. If target is not a mount point, no error is returned.
func Unmount(target string) error {
err := unix.Unmount(target, mntDetach)
if err == nil || err == unix.EINVAL { //nolint:errorlint // unix errors are bare
// Ignore "not mounted" error here. Note the same error
// can be returned if flags are invalid, so this code
// assumes that the flags value is always correct.
return nil
}
return &mountError{
op: "umount",
target: target,
flags: uintptr(mntDetach),
err: err,
}
}
// RecursiveUnmount unmounts the target and all mounts underneath, starting
// with the deepest mount first. The argument does not have to be a mount
// point itself.
func RecursiveUnmount(target string) error {
// Fast path, works if target is a mount point that can be unmounted.
// On Linux, mntDetach flag ensures a recursive unmount. For other
// platforms, if there are submounts, we'll get EBUSY (and fall back
// to the slow path). NOTE we do not ignore EINVAL here as target might
// not be a mount point itself (but there can be mounts underneath).
if err := unix.Unmount(target, mntDetach); err == nil {
return nil
}
// Slow path: get all submounts, sort, unmount one by one.
mounts, err := mountinfo.GetMounts(mountinfo.PrefixFilter(target))
if err != nil {
return err
}
// Make the deepest mount be first
sort.Slice(mounts, func(i, j int) bool {
return len(mounts[i].Mountpoint) > len(mounts[j].Mountpoint)
})
var (
suberr error
lastMount = len(mounts) - 1
)
for i, m := range mounts {
err = Unmount(m.Mountpoint)
if err != nil {
if i == lastMount {
if suberr != nil {
return fmt.Errorf("%w (possible cause: %s)", err, suberr)
}
return err
}
// This is a submount, we can ignore the error for now,
// the final unmount will fail if this is a real problem.
// With that in mind, the _first_ failed unmount error
// might be the real error cause, so let's keep it.
if suberr == nil {
suberr = err
}
}
}
return nil
}