On Mon, Mar 16, 2015 at 03:43:19PM +1100, NeilBrown wrote:
> - if (unlikely(current->total_link_count >= 40))
> + if (unlikely(current->nameidata->total_link_count >= 40))
Huh? nd->total_link_count, please.
>
> - current->total_link_count++;
> + current->nameidata->total_link_count++;
Similar.
> @@ -991,8 +1008,8 @@ static int follow_automount(struct path *path, unsigned
> flags,
> path->dentry->d_inode)
> return -EISDIR;
>
> - current->total_link_count++;
> - if (current->total_link_count >= 40)
> + current->nameidata->total_link_count++;
> + if (current->nameidata->total_link_count >= 40)
> return -ELOOP;
We probably ought to pass nd through follow_mount / follow_automount, instead
of nd->flags, and use nd->total_link_count here.
> - if (unlikely(current->link_count >= MAX_NESTED_LINKS)) {
> + if (unlikely(current->nameidata->link_count >= MAX_NESTED_LINKS)) {
Again, nd->link_count.
> @@ -1948,7 +1965,7 @@ static int path_init(int dfd, const char *name,
> unsigned int flags,
> rcu_read_unlock();
> return -ECHILD;
> done:
> - current->total_link_count = 0;
> + current->nameidata->total_link_count = 0;
... and again.
> return link_path_walk(name, nd);
> }
>
> @@ -2027,7 +2044,9 @@ static int path_lookupat(int dfd, const char *name,
> static int filename_lookup(int dfd, struct filename *name,
> unsigned int flags, struct nameidata *nd)
> {
> - int retval = path_lookupat(dfd, name->name, flags | LOOKUP_RCU, nd);
> + int retval;
> + struct nameidata *saved_nd = set_nameidata(nd);
I'm not sure it's the right place ;-/ I'll play with that a bit and see
if I can get it cleaner...
> - struct nameidata nd;
> + struct nameidata nd, *saved = set_nameidata(&nd);
> void *cookie;
> int res;
>
> @@ -4441,6 +4465,7 @@ int generic_readlink(struct dentry *dentry, char __user
> *buffer, int buflen)
> res = readlink_copy(buffer, buflen, nd_get_link(&nd));
> if (dentry->d_inode->i_op->put_link)
> dentry->d_inode->i_op->put_link(dentry, &nd, cookie);
> + set_nameidata(saved);
> return res;
Now, _that_ is broken - get ERR_PTR(...) from ->follow_link() and you've
leaked nameidata.
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