containerd/mount/lookup_unix.go
Akihiro Suda 0ab2227377 mount: add mount.Lookup for ease of implementing snapshotters
`func Lookup(dir string) (Info, error)` returns the mount
info that corresponds to the dir

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
2017-06-06 09:27:53 +00:00

38 lines
821 B
Go

// +build !windows
package mount
import (
"fmt"
"syscall"
"github.com/pkg/errors"
)
// Lookup returns the mount info corresponds to the path.
func Lookup(dir string) (Info, error) {
var dirStat syscall.Stat_t
if err := syscall.Stat(dir, &dirStat); err != nil {
return Info{}, errors.Wrapf(err, "failed to access %q", dir)
}
mounts, err := Self()
if err != nil {
return Info{}, err
}
for _, m := range mounts {
// Note that m.{Major, Minor} are generally unreliable for our purpose here
// https://www.spinics.net/lists/linux-btrfs/msg58908.html
var st syscall.Stat_t
if err := syscall.Stat(m.Mountpoint, &st); err != nil {
// may fail; ignore err
continue
}
if st.Dev == dirStat.Dev {
return m, nil
}
}
return Info{}, fmt.Errorf("failed to find the mount info for %q", dir)
}