Re: [pnfs] [GIT BISECT] first bad commit: 1f36f774 Switch !O_CREAT case to use of do_last()

Benny Halevy
2010-03-25T14:36:46Z

On Mar. 25, 2010, 16:07 +0200, Benny Halevy <bhalevy@panasas.com> wrote:
> On Mar. 25, 2010, 16:06 +0200, Al Viro <viro@ZenIV.linux.org.uk> wrote:
>> On Thu, Mar 25, 2010 at 03:52:25PM +0200, Benny Halevy wrote:
>>> On Mar. 25, 2010, 15:37 +0200, Al Viro <viro@ZenIV.linux.org.uk> wrote:
>>>> On Thu, Mar 25, 2010 at 03:30:22PM +0200, Boaz Harrosh wrote:
>>>>>> Let's try this: before do_lookup() call there add
>>>>>> if (*want_dir)
>>>>>> nd->flags |= LOOKUP_DIRECTORY;
>>>>> Yes this fixes it!!
>>>>> 2.6.34-rc2 plus above, now works, horay. (diff attached)
>>>>>
>>>>>> and see how does it behave.
>>>>>>
>>>>>> However, even if it does help, it doesn't explain everything. Normal
>>>>>> open() on a directory without O_DIRECTORY if flags shouldn't fail with
>>>>>> -EISDIR. How did that manage to avoid it all along?
>>>> Does open() of directory _without_ O_DIRECTORY work in e.g. vanilla 2.6.33?
>>>> It certainly does for local filesystems and it does for NFSv3; does it work
>>>> for NFSv4?
>>> No, it doesn't.
>>>
>>> # mount localhost:/usr0/nfs4export /mnt/localhost; strace cat /mnt/localhost/server 2>&1 | grep 'open.*server'; umount /mnt/localhost
>>> open("/mnt/localhost/server", O_RDONLY) = 3
>>>
>>> # mount -t nfs4 localhost:/ /mnt/localhost; strace cat /mnt/localhost/server 2>&1 | grep 'open.*server'; umount /mnt/localhost
>>> open("/mnt/localhost/server", O_RDONLY) = -1 EISDIR (Is a directory)
>> Gets better - if you do ls -l /mnt/localhost/server and then repeat that
>> open(), it'll succeed.
>
> Correct :)

So, previously (pre 1f36f77), do_last called do_path_lookup with
lookup_flags(open_flag)|LOOKUP_OPEN and lookup_flags did
- if (f & O_DIRECTORY)
- retval |= LOOKUP_DIRECTORY;

and this was dropped in 1f36f77, right?

Benny

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