wrong hardlink count for /proc/PID directories

wrong hardlink count for /proc/PID directories

[Egmont Koblinger]

Hi,

Tested on some 2.6.[7-9] kernels: a stat call for a /proc/SOMEPID
directory returns a hard link count of 3, which is invalid, since these
directories have three subdirectories (attr, fd and task) and hence the hard
link counter should be 5.

This causes at least 'find' (gnu findutils) to malfunction, it does not
descend under /proc/SOMEPID/fd and /proc/SOMEPID/attr. See also:
https://savannah.gnu.org/bugs/index.php?func=detailitem&item_id=11379



bye,

Egmont

Re: wrong hardlink count for /proc/PID directories

[Jan Engelhardt]

>Hi,
>
>Tested on some 2.6.[7-9] kernels: a stat call for a /proc/SOMEPID
>directory returns a hard link count of 3, which is invalid, since these
>directories have three subdirectories (attr, fd and task) and hence the hard
>link counter should be 5.
>
>This causes at least 'find' (gnu findutils) to malfunction, it does not
>descend under /proc/SOMEPID/fd and /proc/SOMEPID/attr. See also:
>https://savannah.gnu.org/bugs/index.php?func=detailitem&item_id=11379

You could try working around this by using -noleaf. (Which is by no means a 
solution.)

Hm, I have 2.6.8+.9-rc2, and /proc/1 for example has a link count of 3 which 
seems reasonable: ".", "fd" and "task".


Jan Engelhardt
-- 
ENOSPC

Re: wrong hardlink count for /proc/PID directories

[Egmont Koblinger]

On Wed, Dec 22, 2004 at 11:42:33PM +0100, Jan Engelhardt wrote:

> Hm, I have 2.6.8+.9-rc2, and /proc/1 for example has a link count of 3 which 
> seems reasonable: ".", "fd" and "task".

No, it'd have to be 4 in this case: "1" from "/proc", "." from "/proc/1",
".." from "/proc/1/fd" and ".." from "/proc/1/task" all point to "/proc/1".
It should always be the number of real subdirectories plus two.

Just copy this directory recursively to a real filesystem and check the
hardlink count there.



-- 
Egmont

Re: wrong hardlink count for /proc/PID directories

[H. Peter Anvin]

Followup to:  <Pine.LNX.4.61.0412222340540.475@yvahk01.tjqt.qr>
By author:    Jan Engelhardt <jengelh@linux01.gwdg.de>
In newsgroup: linux.dev.kernel
> 
> You could try working around this by using -noleaf. (Which is by no means a 
> solution.)
> 
> Hm, I have 2.6.8+.9-rc2, and /proc/1 for example has a link count of 3 which 
> seems reasonable: ".", "fd" and "task".
> 

You're missing "attr", and you're not counting the directory entry
from below.

directory + "." + "attr/.." + "fd/.." + "task/.." = 5.

It should either return the correct value or set it to 1.

	-hpa