On Wed, Aug 10, 2016 at 5:06 PM, Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> On Wed, 2016-08-10 at 16:46 -0400, Patrick Donnelly wrote:
>> > On Wed, Aug 10, 2016 at 4:30 PM, Jeff Layton <jlayton@xxxxxxxxxx> wrote:
>> >
>> > On Wed, 2016-08-10 at 16:08 -0400, Patrick Donnelly wrote:
>> > >
>> > > > > > On Wed, Aug 10, 2016 at 12:30 PM, Jeff Layton <jlayton@xxxxxxxxxx>
>> > > wrote:
>> > > >
>> > > >
>> > > > The CEPH_INO_DOTDOT thing is quite strange. Under most OS (Linux
>> > > > included), the parent of the root is itself. IOW, at the root, '.'
>> > > > and
>> > > > '..' refer to the same inode.
>> > > >
>> > > > Change the ceph client to do the same, as this allows users to get
>> > > > valid stat info for '..', as well as elimnating some special-
>> > > > casing.
>> > > >
>> > > > > > > > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
>> > >
>> > > Don't forget Client::_lookup:
>> > >
>> > > if (dname == "..") {
>> > > if (dir->dn_set.empty())
>> > > r = -ENOENT;
>> > > else
>> > > *target = dir->get_first_parent()->dir->parent_inode; //dirs
>> > > can't be hard-linked
>> > > goto done;
>> > > }
>> > >
>> > > Otherwise LGTM.
>> > >
>> >
>> >
>> > Ahh, thanks. So will dir->dn_set.empty() be true at the root? If so,
>> > then something like the patch below?
>>
>> Well, that's tricky actually. My understanding is that if dn_set is
>> empty then either the inode is unlinked or it is the root inode (from
>> the client's perspective). So the below patch is probably not quite
>> right? I think if the directory is unlinked but not the root, its ".."
>> should still refer to its first parent? The ENOENT error is probably
>> wrong.
>>
>
> Ok, so is there some way to reliably tell whether it's the root? Should
> we instead check whether it's inode number is CEPH_INO_ROOT ?
Inode::is_root should work. By the way, I see now that the readdir
code is also wrong. It should not need to check dn_set at all (just
is_root()). (It doesn't matter if the directory inode is unlinked, the
parent is still visible.)
--
Patrick Donnelly
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