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feat: support statx STATX_ATTR_MOUNT_ROOT attribute

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Signed-off-by: j4ckstraw <j4ckstraw@foxmail.com>

fix: not use glibc

Signed-off-by: j4ckstraw <j4ckstraw@foxmail.com>

fix linter error
This commit is contained in:
j4ckstraw 2023-08-17 09:58:08 +08:00
parent dbb6927ec2
commit 81ef146e2f
1 changed files with 19 additions and 12 deletions
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31
staging/src/k8s.io/mount-utils/mount_linux.go
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@ -55,6 +55,11 @@ const (
errNotMounted = "not mounted" errNotMounted = "not mounted"
) )
var (
// Error statx support since Linux 4.11, https://man7.org/linux/man-pages/man2/statx.2.html
errStatxNotSupport = errors.New("the statx syscall is not supported. At least Linux kernel 4.11 is needed")
)
// Mounter provides the default implementation of mount.Interface // Mounter provides the default implementation of mount.Interface
// for the linux platform. This implementation assumes that the // for the linux platform. This implementation assumes that the
// kubelet is running in the host's root mount namespace. // kubelet is running in the host's root mount namespace.
@ -385,15 +390,11 @@ func (*Mounter) List() ([]MountPoint, error) {
return ListProcMounts(procMountsPath) return ListProcMounts(procMountsPath)
} }
// statx support since Linux 4.11, glibc 2.28
// refer: https://man7.org/linux/man-pages/man2/statx.2.html
var errNotSupport = errors.New("The statx syscall is not supported. At least Linux kernel 4.11 is needed")
func statx(file string) (unix.Statx_t, error) { func statx(file string) (unix.Statx_t, error) {
var stat unix.Statx_t var stat unix.Statx_t
if err := unix.Statx(0, file, unix.AT_STATX_DONT_SYNC, 0, &stat); err != nil { if err := unix.Statx(0, file, unix.AT_STATX_DONT_SYNC, 0, &stat); err != nil {
if err == unix.ENOSYS { if err == unix.ENOSYS {
return stat, errNotSupport return stat, errStatxNotSupport
} }
return stat, err return stat, err
@ -408,14 +409,12 @@ func statx(file string) (unix.Statx_t, error) {
// It also can distinguish between mountpoints and symbolic links. // It also can distinguish between mountpoints and symbolic links.
// mkdir /tmp/a /tmp/b; mount --bind /tmp/a /tmp/b; IsLikelyNotMountPoint("/tmp/b") // mkdir /tmp/a /tmp/b; mount --bind /tmp/a /tmp/b; IsLikelyNotMountPoint("/tmp/b")
// will return false. When in fact /tmp/b is a mount point. // will return false. When in fact /tmp/b is a mount point.
// TODO(j4ckstraw) add test
func (mounter *Mounter) IsLikelyNotMountPoint(file string) (bool, error) { func (mounter *Mounter) IsLikelyNotMountPoint(file string) (bool, error) {
var stat, rootStat unix.Statx_t var stat, rootStat unix.Statx_t
var err error var err error
if stat, err = statx(file); err != nil { if stat, err = statx(file); err != nil {
if errors.Is(err, errNotSupport) { if errors.Is(err, errStatxNotSupport) {
// not support statx, go slow path // not support statx, go slow path
mnt, mntErr := mounter.IsMountPoint(file) mnt, mntErr := mounter.IsMountPoint(file)
return !mnt, mntErr return !mnt, mntErr
@ -424,15 +423,23 @@ func (mounter *Mounter) IsLikelyNotMountPoint(file string) (bool, error) {
return false, err return false, err
} }
if stat.Attributes_mask != 0 {
if stat.Attributes_mask&unix.STATX_ATTR_MOUNT_ROOT != 0 {
if stat.Attributes&unix.STATX_ATTR_MOUNT_ROOT != 0 {
// file is a mountpoint
return false, nil
} else {
// no need to check rootStat if unix.STATX_ATTR_MOUNT_ROOT supported
return true, nil
}
}
}
root := filepath.Dir(strings.TrimSuffix(file, "/")) root := filepath.Dir(strings.TrimSuffix(file, "/"))
if rootStat, err = statx(root); err != nil { if rootStat, err = statx(root); err != nil {
return false, err return false, err
} }
// TODO add STATX_ATTR_MOUNT_ROOT support, which can check mountpoint correctly.
// Linux 5.8 commit 80340fe3605c0e78cfe496c3b3878be828cfdbfe
// stat->attributes |= STATX_ATTR_MOUNT_ROOT;
// stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;
return !(stat.Dev_major == rootStat.Dev_major && stat.Dev_minor == rootStat.Dev_minor), nil return !(stat.Dev_major == rootStat.Dev_major && stat.Dev_minor == rootStat.Dev_minor), nil
} }