/*
* vfsmount lock must be held for write
*/
-unsigned int mnt_get_count(struct mount *mnt)
+int mnt_get_count(struct mount *mnt)
{
#ifdef CONFIG_SMP
- unsigned int count = 0;
+ int count = 0;
int cpu;
for_each_possible_cpu(cpu) {
static void mntput_no_expire(struct mount *mnt)
{
LIST_HEAD(list);
+ int count;
rcu_read_lock();
if (likely(READ_ONCE(mnt->mnt_ns))) {
*/
smp_mb();
mnt_add_count(mnt, -1);
- if (mnt_get_count(mnt)) {
+ count = mnt_get_count(mnt);
+ if (count != 0) {
+ WARN_ON(count < 0);
rcu_read_unlock();
unlock_mount_hash();
return;
{
struct mount *mnt = real_mount(path->mnt);
- if (flags & ~(MNT_FORCE | MNT_DETACH | MNT_EXPIRE | UMOUNT_NOFOLLOW))
- return -EINVAL;
if (!may_mount())
return -EPERM;
if (path->dentry != path->mnt->mnt_root)
return 0;
}
+// caller is responsible for flags being sane
int path_umount(struct path *path, int flags)
{
struct mount *mnt = real_mount(path->mnt);
struct path path;
int ret;
+ // basic validity checks done first
+ if (flags & ~(MNT_FORCE | MNT_DETACH | MNT_EXPIRE | UMOUNT_NOFOLLOW))
+ return -EINVAL;
+
if (!(flags & UMOUNT_NOFOLLOW))
lookup_flags |= LOOKUP_FOLLOW;
ret = user_path_at(AT_FDCWD, name, lookup_flags, &path);