Re: fcntl(F_GETPATH) support

[christos%astron.com@localhost (Christos Zoulas)]

In article <2F29CA9A-0AE1-48D3-B3F4-1556912D4C22%me.com@localhost>,
Jason Thorpe  <thorpej%me.com@localhost> wrote:
>
>
>> On Sep 14, 2019, at 2:52 PM, Kamil Rytarowski <n54%gmx.com@localhost> wrote:
>> 
>> On 14.09.2019 23:34, Christos Zoulas wrote:
>>> Comments?
>>> 
>> 
>> Question. How does it handle symbolic/hardlinks?
>
>Symbolic links, of course, are simply continuations of the lookup, so
>there's "nothing to see here" with a symbolic link.

If you can get a file desriptor to a symlink, it will work; I don't think
that we have a way to do this now.

>I looked at cache_revlookup() and it looks to me like it simply picks
>the first hit it finds in the hash table for the given vnode.

That is correct.

>At least one platform that support this API uses "the last name the file
>was looked up with", and will fall back on "whatever the underlying file
>system considers to be the canonical name for the file", which is file
>system-defined, if for some reason there is no entry in the name cache
>(which could, for example, happen if an application is doing an
>"open-by-file-id" type operation and the file has not yet been opened by
>path name).

It will also fail if the entry has been evicted from the cache, but that
rarely happens with recently opened files.

christos