RE: rm -rf -> Circular directory structure

RE: rm -rf -> Circular directory structure

[Igor V. Kovalenko]

Looking at ...include/sys/types.h I found that ino_t is actually
unsigned short, that is only 16 bit in size. Thus, we (in 'rm' etc..)
do compare the lower 16 bits of prepared by hash_path_name()
32-bit integer.
  I think this is a main cause for $subj$, though the hashing
function itself is not as perfect as it could be (in theory).

PS: Or do I have incorrect header file?
--
Igor V. Kovalenko   mailto:iko@crec.mipt.ru
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Re: rm -rf -> Circular directory structure

[Fergus Henderson]

"Igor V. Kovalenko" <iko@crec.mipt.ru> writes:

>Looking at ...include/sys/types.h I found that ino_t is actually
>unsigned short, that is only 16 bit in size. Thus, we (in 'rm' etc..)
>do compare the lower 16 bits of prepared by hash_path_name()
>32-bit integer.
>  I think this is a main cause for $subj$, though the hashing
>function itself is not as perfect as it could be (in theory).

The whole idea of using a hash function to compute inode numbers
is fundamentally broken.  Perhaps it would be better to think
about a solution that works rather than making a fundamentally
broken one slightly less broken.

--
Fergus Henderson <fjh@cs.mu.oz.au>   |  "I have always known that the pursuit
WWW: < http://www.cs.mu.oz.au/~fjh >   |  of excellence is a lethal habit"
PGP: finger fjh@128.250.37.3         |     -- the last words of T. S. Garp.
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RE: rm -rf -> Circular directory structure

[Sergey Okhapkin]

Michael A. Chase wrote:
>  I'm using Sergey's cygwin.dll dated 31 July and bash.exe dated 4 July.
> When I try to delete a large directory tree, I still see this problem.
> 

The hash function used to convert filename to inode number is very simple. Do you know any fast and good hash?

-- 
Sergey Okhapkin, http://www.lexa.ru/sos
Moscow, Russia
Looking for a job.


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Re: rm -rf -> Circular directory structure

[Michael A. Chase]

 I'm using Sergey's cygwin.dll dated 31 July and bash.exe dated 4 July.
When I try to delete a large directory tree, I still see this problem.

Mac :})

-----Original Message-----
From: Larry Hall <lhall@rfk.com>
To: Christoph Kukulies <kuku@gilberto.physik.RWTH-Aachen.DE>;
gnu-win32@cygnus.com <gnu-win32@cygnus.com>
Date: Wednesday, August 06, 1997 10:54
Subject: Re: rm -rf -> Circular directory structure



>At 11:19 AM 8/6/97 +0200, Christoph Kukulies wrote:
>>I'm having a weird problem under NT 4.0 (I remember to
>>have seen this with b17 and NT3.51 also):
>>
>>D:\>rm -rf somedir
>>rm: WARNING: Circular directory structure.
>>This almost certainly means that you have a corrupted file system.
>>NOTIFY YOUR SYSTEM MANAGER.
>>Cycle detected:
>>somedir/FOO/FOO
>>is the same file as
>>somedir
>>
>>CHKDSK doesn't flag any errors on the filesystem and I tend to believe
>>this isn't the cause anyway.
>>
>>The interesting thing is: When I remove the file somedir/FOO/FOO
>>the rm command is able to run through without errors.
>>
>>
>>--
>>Chris Christoph P. U. Kukulies kuku@gil.physik.rwth-aachen.de
>
>Chris,
>
>This should be in the FAQ (I expect its not at the moment).  The problem
>is caused by a faulty inode mapping algorithm in all the betas.  There
is
>no problem with your file system.  It merely means that the faulty inode
>mapping for files and directories thinks there's more than 1 file and/or
>directory for the generated inode number, which is certainly a bad thing
>for traditional UNIX file systems.  The error hinders rm from working
>correctly but does not indicate file system problems.  You'll just need
>to delete the intended files/directories another way (most likely via
>Windows or DOS tools).  I believe Sergey's latest DLL has some fixes to
>mitigate this problem.  I don't think there's a complete fix yet
(correct
>me if I'm wrong folks).
>
>Larry Hall                              lhall@rfk.com
>RFK Partners, Inc.                      (617) 239-1053
>8 Grove Street                          (617) 239-1655 - FAX
>Wellesley, MA  02181
>
>-
>For help on using this list (especially unsubscribing), send a message
to
>"gnu-win32-request@cygnus.com" with one line of text: "help".
>

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Re: rm -rf -> Circular directory structure

[Fergus Henderson]

Christoph Kukulies <kuku@gilberto.physik.RWTH-Aachen.DE> writes:

>I'm having a weird problem under NT 4.0 (I remember to
>have seen this with b17 and NT3.51 also):
>
>D:\>rm -rf somedir
>rm: WARNING: Circular directory structure.
>This almost certainly means that you have a corrupted file system.
>NOTIFY YOUR SYSTEM MANAGER.
>Cycle detected:
>somedir/FOO/FOO
>is the same file as
>somedir

This is because the algorithm that cygwin uses to compute inode numbers
just hashes the file name (or something like that) rather than
actually figuring out a properly unique number.  When you get a hash
collision, `rm' gets confused.

--
Fergus Henderson <fjh@cs.mu.oz.au>   |  "I have always known that the pursuit
WWW: < http://www.cs.mu.oz.au/~fjh >   |  of excellence is a lethal habit"
PGP: finger fjh@128.250.37.3         |     -- the last words of T. S. Garp.
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Re: rm -rf -> Circular directory structure

[Larry Hall]

At 11:19 AM 8/6/97 +0200, Christoph Kukulies wrote:
>I'm having a weird problem under NT 4.0 (I remember to
>have seen this with b17 and NT3.51 also):
>
>D:\>rm -rf somedir
>rm: WARNING: Circular directory structure.
>This almost certainly means that you have a corrupted file system.
>NOTIFY YOUR SYSTEM MANAGER.
>Cycle detected:
>somedir/FOO/FOO
>is the same file as
>somedir
>
>CHKDSK doesn't flag any errors on the filesystem and I tend to believe
>this isn't the cause anyway.
>
>The interesting thing is: When I remove the file somedir/FOO/FOO
>the rm command is able to run through without errors.
>
>
>-- 
>Chris Christoph P. U. Kukulies kuku@gil.physik.rwth-aachen.de

Chris,

This should be in the FAQ (I expect its not at the moment).  The problem
is caused by a faulty inode mapping algorithm in all the betas.  There is
no problem with your file system.  It merely means that the faulty inode
mapping for files and directories thinks there's more than 1 file and/or
directory for the generated inode number, which is certainly a bad thing
for traditional UNIX file systems.  The error hinders rm from working 
correctly but does not indicate file system problems.  You'll just need
to delete the intended files/directories another way (most likely via 
Windows or DOS tools).  I believe Sergey's latest DLL has some fixes to 
mitigate this problem.  I don't think there's a complete fix yet (correct
me if I'm wrong folks).

Larry Hall                              lhall@rfk.com
RFK Partners, Inc.                      (617) 239-1053
8 Grove Street                          (617) 239-1655 - FAX
Wellesley, MA  02181                             

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rm -rf -> Circular directory structure

[Christoph Kukulies]

I'm having a weird problem under NT 4.0 (I remember to
have seen this with b17 and NT3.51 also):

D:\>rm -rf somedir
rm: WARNING: Circular directory structure.
This almost certainly means that you have a corrupted file system.
NOTIFY YOUR SYSTEM MANAGER.
Cycle detected:
somedir/FOO/FOO
is the same file as
somedir

CHKDSK doesn't flag any errors on the filesystem and I tend to believe
this isn't the cause anyway.

The interesting thing is: When I remove the file somedir/FOO/FOO
the rm command is able to run through without errors.


-- 
Chris Christoph P. U. Kukulies kuku@gil.physik.rwth-aachen.de
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