-/*
- * SMP-safe: Returns 1 and nd will have valid dentry and mnt, if
- * everything is done. Returns 0 and drops input nd, if lookup failed;
- */
-static int __emul_lookup_dentry(const char *name, struct nameidata *nd)
-{
- if (path_walk(name, nd))
- return 0; /* something went wrong... */
-
- if (!nd->dentry->d_inode || S_ISDIR(nd->dentry->d_inode->i_mode)) {
- struct dentry *old_dentry = nd->dentry;
- struct vfsmount *old_mnt = nd->mnt;
- struct qstr last = nd->last;
- int last_type = nd->last_type;
- struct fs_struct *fs = current->fs;
-
- /*
- * NAME was not found in alternate root or it's a directory.
- * Try to find it in the normal root:
- */
- nd->last_type = LAST_ROOT;
- read_lock(&fs->lock);
- nd->mnt = mntget(fs->rootmnt);
- nd->dentry = dget(fs->root);
- read_unlock(&fs->lock);
- if (path_walk(name, nd) == 0) {
- if (nd->dentry->d_inode) {
- dput(old_dentry);
- mntput(old_mnt);
- return 1;
- }
- path_release(nd);
- }
- nd->dentry = old_dentry;
- nd->mnt = old_mnt;
- nd->last = last;
- nd->last_type = last_type;
- }
- return 1;
-}
-
-void set_fs_altroot(void)
-{
- char *emul = __emul_prefix();
- struct nameidata nd;
- struct vfsmount *mnt = NULL, *oldmnt;
- struct dentry *dentry = NULL, *olddentry;
- int err;
- struct fs_struct *fs = current->fs;
-
- if (!emul)
- goto set_it;
- err = path_lookup(emul, LOOKUP_FOLLOW|LOOKUP_DIRECTORY|LOOKUP_NOALT, &nd);
- if (!err) {
- mnt = nd.mnt;
- dentry = nd.dentry;
- }
-set_it:
- write_lock(&fs->lock);
- oldmnt = fs->altrootmnt;
- olddentry = fs->altroot;
- fs->altrootmnt = mnt;
- fs->altroot = dentry;
- write_unlock(&fs->lock);
- if (olddentry) {
- dput(olddentry);
- mntput(oldmnt);
- }
-}
-