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* symlinks follow 8 or 5?
@ 2004-07-29  5:34 FabF
  2004-07-30  3:14 ` Tim Connors
  0 siblings, 1 reply; 6+ messages in thread
From: FabF @ 2004-07-29  5:34 UTC (permalink / raw)
  To: lkml

Hi,
	do_follow_link comments is "This limits recursive symlink follows to 8"
... but having (x=1->10) ln -s x+1 x and trying cat 1 just works for x <
7 which drops follow mode to 5.Is this irrelevant ?

Regards,
FabF
  


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: symlinks follow 8 or 5?
  2004-07-29  5:34 symlinks follow 8 or 5? FabF
@ 2004-07-30  3:14 ` Tim Connors
  2004-07-30  7:16   ` Arjan van de Ven
  0 siblings, 1 reply; 6+ messages in thread
From: Tim Connors @ 2004-07-30  3:14 UTC (permalink / raw)
  To: FabF; +Cc: lkml

FabF <fabian.frederick@skynet.be> said on Thu, 29 Jul 2004 07:34:39 +0200:
> Hi,
> 	do_follow_link comments is "This limits recursive symlink follows to 8"
> ... but having (x=1->10) ln -s x+1 x and trying cat 1 just works for x <
> 7 which drops follow mode to 5.Is this irrelevant ?

This popped up a few years ago.
http://www.ussg.iu.edu/hypermail/linux/kernel/9903.1/0018.html

Obviously, nothing came about it. And I suspect the problem (running
out of stack space) is even worse these days with 4k stacks. Why is
this even done recursively?

Note that 5 symlinks is quite a burden. I got hit by it a few days ago
with my farm of symlinks between nfs RAID disks and my home directory
(~/raid points to /nfs/cluster, papers refers to ~/raid/papers,
Astro-ph refers to ~/papers/Astro-ph, and then I autofs shfs mounted
~/ from another host, which involve a couple of symlinks again (/host
to /mnt/nfshost and /mnt/nfshost to /var/autofs/misc/host and ~/host
to /host - the first two so that when the network goes down, all I
have to do is remove (by script) /mnt/nfshost, and then autofs wont
try to mount something it can't when something tries to access
~/host)).

-- 
TimC -- http://astronomy.swin.edu.au/staff/tconnors/
"We must use Tim as a tool, not as a couch." -- J F Kennedy

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: symlinks follow 8 or 5?
  2004-07-30  3:14 ` Tim Connors
@ 2004-07-30  7:16   ` Arjan van de Ven
  2004-07-30 16:42     ` Ulrich Drepper
  0 siblings, 1 reply; 6+ messages in thread
From: Arjan van de Ven @ 2004-07-30  7:16 UTC (permalink / raw)
  To: Tim Connors; +Cc: FabF, lkml

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> Obviously, nothing came about it. 

you haven't been paying attention.... the current 2.6 kernels have a
patch series that is fixing this for most filesystems already with the
last few others in progress.

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^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: symlinks follow 8 or 5?
  2004-07-30  7:16   ` Arjan van de Ven
@ 2004-07-30 16:42     ` Ulrich Drepper
  2004-07-30 16:51       ` Arjan van de Ven
  0 siblings, 1 reply; 6+ messages in thread
From: Ulrich Drepper @ 2004-07-30 16:42 UTC (permalink / raw)
  To: arjanv; +Cc: lkml

Arjan van de Ven wrote:

> you haven't been paying attention.... the current 2.6 kernels have a
> patch series that is fixing this for most filesystems already 

Which reminds me: how can we safely determine whether this is
implemented for a local filesystem from userland?  Unless we can do I
cannot change the value of SYMLOOP_MAX and people will not be able to
take advantage of the raised limit safely.

-- 
➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: symlinks follow 8 or 5?
  2004-07-30 16:42     ` Ulrich Drepper
@ 2004-07-30 16:51       ` Arjan van de Ven
  2004-07-30 18:16         ` Helge Hafting
  0 siblings, 1 reply; 6+ messages in thread
From: Arjan van de Ven @ 2004-07-30 16:51 UTC (permalink / raw)
  To: Ulrich Drepper; +Cc: lkml

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On Fri, Jul 30, 2004 at 09:42:46AM -0700, Ulrich Drepper wrote:
> Arjan van de Ven wrote:
> 
> > you haven't been paying attention.... the current 2.6 kernels have a
> > patch series that is fixing this for most filesystems already 
> 
> Which reminds me: how can we safely determine whether this is
> implemented for a local filesystem from userland?  Unless we can do I
> cannot change the value of SYMLOOP_MAX and people will not be able to
> take advantage of the raised limit safely.

well actually it can't be per userland; it's just that we're almost at the
point where all filesystems are switched to the new infrastructure so that
the global constant can be bumped to 8 again...

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^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: symlinks follow 8 or 5?
  2004-07-30 16:51       ` Arjan van de Ven
@ 2004-07-30 18:16         ` Helge Hafting
  0 siblings, 0 replies; 6+ messages in thread
From: Helge Hafting @ 2004-07-30 18:16 UTC (permalink / raw)
  To: Arjan van de Ven; +Cc: Ulrich Drepper, lkml

On Fri, Jul 30, 2004 at 06:51:53PM +0200, Arjan van de Ven wrote:
> On Fri, Jul 30, 2004 at 09:42:46AM -0700, Ulrich Drepper wrote:
> > 
> > Which reminds me: how can we safely determine whether this is
> > implemented for a local filesystem from userland?  Unless we can do I
> > cannot change the value of SYMLOOP_MAX and people will not be able to
> > take advantage of the raised limit safely.
> 
> well actually it can't be per userland; it's just that we're almost at the
> point where all filesystems are switched to the new infrastructure so that
> the global constant can be bumped to 8 again...

Well, one can test it from userland - make a tempdir and create progressively
longer link chains until it fails.  Quirky, sure.

Helge Hafting


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2004-07-30 18:15 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2004-07-29  5:34 symlinks follow 8 or 5? FabF
2004-07-30  3:14 ` Tim Connors
2004-07-30  7:16   ` Arjan van de Ven
2004-07-30 16:42     ` Ulrich Drepper
2004-07-30 16:51       ` Arjan van de Ven
2004-07-30 18:16         ` Helge Hafting

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