Messages in this thread | | | Date | Tue, 9 Feb 2016 11:34:11 +0100 | Subject | Re: [RFC PATCH 1/3] debugfs: fix automount inode i_nlink references | From | Roman Peniaev <> |
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On Mon, Feb 8, 2016 at 5:35 PM, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > On Mon, Feb 08, 2016 at 11:28:52AM +0100, Roman Peniaev wrote: >> On Mon, Feb 8, 2016 at 7:38 AM, Greg Kroah-Hartman >> <gregkh@linuxfoundation.org> wrote: >> > On Thu, Dec 10, 2015 at 01:47:12PM +0100, Roman Pen wrote: >> >> Directory inodes should start off with i_nlink == 2 (for "." entry). >> >> Of course the same rule should be applied to automount dentries for >> >> child and parent inodes as well. >> >> >> >> Also now automount dentry does fsnotify_mkdir. >> >> >> >> Without this patch kernel complains when sees i_nlink == 0: >> > >> > How can the kernel see this? What did you do to trigger this? >> >> Yes, sorry, I had to be more precise on this. >> That happens on unlinking of automount dentry. >> >> Easily can be reproduced: >> >> autom = debugfs_create_automount("automount", parentd, vfsmount_cb, data); >> BUG_ON(IS_ERR_OR_NULL(autom)); >> debugfs_remove(autom); >> >> You will immediately see one warning on attempt to drop_nlink() (which is zero) >> for automount dentry. > > Why don't we see this "in the wild" today with the one user of this > function?
I see only one current user: tracefs. tracefs does not remove the automount root dentry. That's the reason.
> >> The second warning happens when you unlink 'parentd', because >> debugfs_create_automount() did not increase the nlink for parent >> inode. >> >> Do I need to resend this patch with more precise description? > > Yes, please fix up and resend as a stand-alone patch, as it is > independant of your other proposal. > > And take off the "RFC" marking, I can never apply a patch with that type > of marking as you obviously don't think it is good enough to be merged, > so why would I? :)
I've resent a patch. Please, take a look.
-- Roman
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