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

[Benny Halevy <bhalevy@panasas.com>]

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)