Messages in this thread | | | Date | Fri, 9 Apr 2021 01:35:05 +0000 | From | Al Viro <> | Subject | Re: [PATCH v3 2/4] kernfs: use VFS negative dentry caching |
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On Fri, Apr 09, 2021 at 09:15:06AM +0800, Ian Kent wrote: > + parent = kernfs_dentry_node(dentry->d_parent); > + if (parent) { > + const void *ns = NULL; > + > + if (kernfs_ns_enabled(parent)) > + ns = kernfs_info(dentry->d_parent->d_sb)->ns;
For any dentry d, we have d->d_parent->d_sb == d->d_sb. All the time. If you ever run into the case where that would not be true, you've found a critical bug.
> + kn = kernfs_find_ns(parent, dentry->d_name.name, ns); > + if (kn) > + goto out_bad; > + }
Umm... What's to prevent a race with successful rename(2)? IOW, what's there to stabilize ->d_parent and ->d_name while we are in that function?
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