Re: [RFC][PATCH 6/14] Union-mount dentry reference counting

Jan Engelhardt
2007-05-14T20:59:35Z

On May 14 2007 15:11, Bharata B Rao wrote:
>+void __union_check(struct dentry *dentry)
>+{
>+ if (likely(!(dentry->d_topmost || dentry->d_overlaid))) {

This could be simplified to

if (likely(!dentry->d_topmost && !dentry->d_overlaid))

(I prefer x==NULL over !x for pointers, though)
And then again, do not assume everything is (un)likely [also elsewhere].

>+ if (unlikely(dentry->d_union)) {
>+ printk(KERN_ERR "%s: \"%s\" stale union reference\n" \
>+ "\tdentry=%p, inode=%p, count=%d, u_count=%d\n",
>+ __FUNCTION__,
>+ dentry->d_name.name,
>+ dentry,
>+ dentry->d_inode,
>+ atomic_read(&dentry->d_count),
>+ atomic_read(&dentry->d_union->u_count));
>+ dump_stack();
>+ }
>+ return;
>+ }
>+
>--- a/net/unix/af_unix.c
>+++ b/net/unix/af_unix.c
>@@ -1082,8 +1082,11 @@ restart:
> newu->addr = otheru->addr;
> }
> if (otheru->dentry) {
>- newu->dentry = dget(otheru->dentry);
>+ /* Is this safe here? I don't know ... */

Figure it out :)

Jan
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