Re: [PATCH v3 2/5] ovl: relax same fs constrain for constant st_ino

[Amir Goldstein <amir73il@gmail.com>]

On Thu, Jun 1, 2017 at 10:55 PM, Miklos Szeredi <miklos@szeredi.hu> wrote:
> On Thu, Jun 1, 2017 at 11:02 AM, Amir Goldstein <amir73il@gmail.com> wrote:
>> For the case of all layers not on the same fs, use the copy up
>> origin st_ino/st_dev for non-dir, if we know it.
>>
>> This guarantied constant and persistent st_ino/st_dev for non-dir,
>> but not system-wide uniqueness, like in the same fs case.
>
> I'd rather leave this until the st_dev uniqueness is sorted out.   Non
> unique st_ino/st_dev is just asking for trouble.
>

I don't mind leaving this out, but you do realize that this commit
doesn't change st_dev/st_ino uniqueness one way or the other, right?

- Directory st_dev/st_ino *remains* constant, unique and non-persistent
- Non-dir st_dev/st_ino *remains* non-unique, but becomes constant and
persistent

So I can't really see the harm in this patch.

Nevertheless, let me know if you want me to re-post consistent d_ino without
the non-samefs relax patches. Actually, consistent d_ino patch is
correct with or
without the non-samefs relax patches, but it misses an optimization for skipping
vfs_getattr() for (impure && !samefs) case.

Amir.