* to restart the path walk from the beginning in ref-walk mode.
*/
-static inline void lock_rcu_walk(void)
-{
- br_read_lock(&vfsmount_lock);
- rcu_read_lock();
-}
-
-static inline void unlock_rcu_walk(void)
-{
- rcu_read_unlock();
- br_read_unlock(&vfsmount_lock);
-}
-
/**
* unlazy_walk - try to switch to ref-walk mode.
* @nd: nameidata pathwalk data
BUG_ON(!(nd->flags & LOOKUP_RCU));
/*
- * Get a reference to the parent first: we're
- * going to make "path_put(nd->path)" valid in
- * non-RCU context for "terminate_walk()".
- *
- * If this doesn't work, return immediately with
- * RCU walking still active (and then we will do
- * the RCU walk cleanup in terminate_walk()).
+ * After legitimizing the bastards, terminate_walk()
+ * will do the right thing for non-RCU mode, and all our
+ * subsequent exit cases should rcu_read_unlock()
+ * before returning. Do vfsmount first; if dentry
+ * can't be legitimized, just set nd->path.dentry to NULL
+ * and rely on dput(NULL) being a no-op.
*/
- if (!lockref_get_not_dead(&parent->d_lockref))
+ if (!legitimize_mnt(nd->path.mnt, nd->m_seq))
return -ECHILD;
-
- /*
- * After the mntget(), we terminate_walk() will do
- * the right thing for non-RCU mode, and all our
- * subsequent exit cases should unlock_rcu_walk()
- * before returning.
- */
- mntget(nd->path.mnt);
nd->flags &= ~LOOKUP_RCU;
+ if (!lockref_get_not_dead(&parent->d_lockref)) {
+ nd->path.dentry = NULL;
+ rcu_read_unlock();
+ return -ECHILD;
+ }
+
/*
* For a negative lookup, the lookup sequence point is the parents
* sequence point, and it only needs to revalidate the parent dentry.
spin_unlock(&fs->lock);
}
- unlock_rcu_walk();
+ rcu_read_unlock();
return 0;
unlock_and_drop_dentry:
spin_unlock(&fs->lock);
drop_dentry:
- unlock_rcu_walk();
+ rcu_read_unlock();
dput(dentry);
goto drop_root_mnt;
out:
- unlock_rcu_walk();
+ rcu_read_unlock();
drop_root_mnt:
if (!(nd->flags & LOOKUP_ROOT))
nd->root.mnt = NULL;
if (!(nd->flags & LOOKUP_ROOT))
nd->root.mnt = NULL;
+ if (!legitimize_mnt(nd->path.mnt, nd->m_seq)) {
+ rcu_read_unlock();
+ return -ECHILD;
+ }
if (unlikely(!lockref_get_not_dead(&dentry->d_lockref))) {
- unlock_rcu_walk();
+ rcu_read_unlock();
+ mntput(nd->path.mnt);
return -ECHILD;
}
if (read_seqcount_retry(&dentry->d_seq, nd->seq)) {
- unlock_rcu_walk();
+ rcu_read_unlock();
dput(dentry);
+ mntput(nd->path.mnt);
return -ECHILD;
}
- mntget(nd->path.mnt);
- unlock_rcu_walk();
+ rcu_read_unlock();
}
if (likely(!(nd->flags & LOOKUP_JUMPED)))
struct mount *parent;
struct dentry *mountpoint;
- br_read_lock(&vfsmount_lock);
+ read_seqlock_excl(&mount_lock);
parent = mnt->mnt_parent;
if (parent == mnt) {
- br_read_unlock(&vfsmount_lock);
+ read_sequnlock_excl(&mount_lock);
return 0;
}
mntget(&parent->mnt);
mountpoint = dget(mnt->mnt_mountpoint);
- br_read_unlock(&vfsmount_lock);
+ read_sequnlock_excl(&mount_lock);
dput(path->dentry);
path->dentry = mountpoint;
mntput(path->mnt);
/* Something is mounted on this dentry in another
* namespace and/or whatever was mounted there in this
- * namespace got unmounted before we managed to get the
- * vfsmount_lock */
+ * namespace got unmounted before lookup_mnt() could
+ * get it */
}
/* Handle an automount point */
if (!d_mountpoint(path->dentry))
break;
- mounted = __lookup_mnt(path->mnt, path->dentry, 1);
+ mounted = __lookup_mnt(path->mnt, path->dentry);
if (!mounted)
break;
path->mnt = &mounted->mnt;
{
while (d_mountpoint(nd->path.dentry)) {
struct mount *mounted;
- mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry, 1);
+ mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry);
if (!mounted)
break;
nd->path.mnt = &mounted->mnt;
nd->flags &= ~LOOKUP_RCU;
if (!(nd->flags & LOOKUP_ROOT))
nd->root.mnt = NULL;
- unlock_rcu_walk();
+ rcu_read_unlock();
return -ECHILD;
}
nd->flags &= ~LOOKUP_RCU;
if (!(nd->flags & LOOKUP_ROOT))
nd->root.mnt = NULL;
- unlock_rcu_walk();
+ rcu_read_unlock();
}
}
nd->path = nd->root;
nd->inode = inode;
if (flags & LOOKUP_RCU) {
- lock_rcu_walk();
+ rcu_read_lock();
nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
+ nd->m_seq = read_seqbegin(&mount_lock);
} else {
path_get(&nd->path);
}
nd->root.mnt = NULL;
+ nd->m_seq = read_seqbegin(&mount_lock);
if (*name=='/') {
if (flags & LOOKUP_RCU) {
- lock_rcu_walk();
+ rcu_read_lock();
set_root_rcu(nd);
} else {
set_root(nd);
struct fs_struct *fs = current->fs;
unsigned seq;
- lock_rcu_walk();
+ rcu_read_lock();
do {
seq = read_seqcount_begin(&fs->seq);
if (f.need_put)
*fp = f.file;
nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
- lock_rcu_walk();
+ rcu_read_lock();
} else {
path_get(&nd->path);
fdput(f);