Re: Can getdents return zero inode numbers?

[Florian Weimer <fweimer@redhat.com>]

On 04/19/2016 04:48 PM, Eric Sandeen wrote:
>
>
> On 3/11/16 4:20 PM, Andreas Dilger wrote:
>> On Mar 11, 2016, at 10:34 AM, Florian Weimer <fweimer@redhat.com> wrote:
>>>
>>> Is it possible that getdents returns a zero inode number for a name
>>> which actually has a file (or directory, device node etc.) behind it?
>>
>> The d_ino == 0 value is valid to return and means that the filename was
>> unlinked from the directory but the entry was not actually removed.
>
> Until recently, didn't the filesystems which use get_next_ino() accept
> inode 0 as a legit inode number?

Thanks Eric for unearthing this change.

> commit 2adc376c551943a07170cbe70f43e6d6065f8906
> Author: Carlos Maiolino <cmaiolino@redhat.com>
> Date:   Thu Jun 25 12:25:58 2015 -0300
>
>      vfs: avoid creation of inode number 0 in get_next_ino

As far as I understand it, this does nothing to fix up existing files 
with inode 0, so I filed bugs to fix this in glibc as well:

https://sourceware.org/bugzilla/show_bug.cgi?id=19970
https://sourceware.org/bugzilla/show_bug.cgi?id=19971

We had no idea on the glibc side that this wasn't just a theoretical issue.

Thanks,
Florian