Linux 2.4 NFS bug (annoying sylmlinx breakage)

Linux 2.4 NFS bug (annoying sylmlinx breakage)

[Dylan Griffiths]

	I've noticed this bug before.  Between two hosts on a 100Mbps switched lan, 
symlinks are trashed into garbage.  Based on the output. I'm guessing a 
string loses its null somewhere.

Client is 2.4.14.  Server is 2.4.10.  Server has RAID 5 IDE softraid and 
an hpt370 driver patch provided by Tim Hockin to fix the deadlocks and 
oopsies of the hpt366 driver on my hpt370.

Both are configured with NFSv3 client and server support.  Both use Intel 
EEPro 100s.

I've been working on Mozilla again lately, but I don't have enough free HD 
space sitting on my main workstation to build on.  Luckily I have a large 
NFS home directory.  However, after configure has been run, most of the 
symlinks are mangled:

dylang@shadowgate:/builds/mozilla$ ls -l /builds/mozilla/dist/include/nspr
total 12
drwxr-xr-x    2 dylang   web          4096 Jan 14 14:24 md/
lrwxrwxrwx    1 dylang   web          1184 Jan 14 14:24 nspr.h -> 
../../../nsprpub/pr/include/./nspr.h\ 
$(MOD_DEPTH)/config/autoconf.mk\n\nHEADERS\ \=\ $(wildcard\ 
$(srcdir)/\*.h)\nCONFIGS\ \=\ $(wildcard\ $(srcdir)/\*.cfg)\n\ninclude\ 
$(topsrcdir)/config/rules.mk\n\nexport::\ $(MDCPUCFG_H)\n\t$(INSTALL)\ -m\ 
444\ $(srcdir)/$(MDCPUCFG_H)\ $(dist_includedir)\n\t$(INSTALL)\ -m\ 444\ 
$(CONFIGS)\ $(HEADERS)\ $(dist_includedir)/md\nifneq\ 
($(OS_ARCH),OpenVMS)\n\tmv\ -f\ $(dist_includedir)/$(MDCPUCFG_H)\ 
$(dist_includedir)/prcpucfg.h\nelse\n#\ mv'ing\ a\ link\ causes\ the\ 
file\ itself\ to\ move,\ not\ the\ link.\n\trm\ -f\ 
$(dist_includedir)/$(MDCPUCFG_H)\n\trm\ -f\ 
$(dist_includedir)/prcpucfg.h\n\tln\ -fs\ $(srcdir)/$(MDCPUCFG_H)\ 
$(dist_includedir)/prcpucfg.h\nendif\n\nreal_install::\n\t$(NSINSTALL)\ 
-D\ $(DESTDIR)$(includedir)/md\n\tcp\ $(srcdir)/$(MDCPUCFG_H)\ 
$(DESTDIR)$(includedir)/prcpucfg.h\n\t$(NSINSTALL)\ -t\ -m\ 644\ 
$(CONFIG)\ $(HEADERS)\ $(DESTDIR)$(includedir)/md\n\nrelease::\ 
export\n\t\@echo\ "Copying\ machine-dependent\ prcpucfg.h"\n\t\@if\ test\ 
-z\ "$(BUILD_NUMBER)";\ then\ \\\n\t\techo\ "BUILD_NUMBER\ must\ be\ 
defined";\ \\\n\t\tfalse;\ \\\n\tfi\n\t\@if\ test\ !\ -d\ 
$(RELEASE_INCLUDE_DIR);\ then\ \\\n\t\trm\ -rf\ $(RELEASE_INCLUDE_DIR);\ 
\\\n\t\t$(NSINSTALL)\ -D\ $(RELEASE_INCLUDE_DIR);\\\n\tfi\n\tcp\ 
$(srcdir)/$(MDCPUCFG_H)\ $(RELEASE_INCLUDE_DIR)/prcpucfg.h\n

...

Some of them are fine:
lrwxrwxrwx    1 dylang   web            37 Jan 14 14:24 prenv.h -> 
../../../nsprpub/pr/include/./prenv.h
lrwxrwxrwx    1 dylang   web            37 Jan 14 14:24 prerr.h -> 
../../../nsprpub/pr/include/./prerr.h
lrwxrwxrwx    1 dylang   web            39 Jan 14 14:24 prerror.h -> 
../../../nsprpub/pr/include/./prerror.h
lrwxrwxrwx    1 dylang   web            38 Jan 14 14:24 prinet.h -> 
../../../nsprpub/pr/include/./prinet.h
lrwxrwxrwx    1 dylang   web            38 Jan 14 14:24 prinit.h -> 
../../../nsprpub/pr/include/./prinit.h

I figure it's a script error in the latest code.  So I go and start to 
manually fix the symlinks.  But then, as I was fixing the 4th one:

dylang@shadowgate:/builds/mozilla/dist/include/nspr$ ls -l pripcsem.h
lrwxrwxrwx    1 dylang   web            41 Jan 14 14:24 pripcsem.h -> 
../../../nsprpub/pr/include/./pripcsem.h\200
dylang@shadowgate:/builds/mozilla/dist/include/nspr$ rm pripcsem.h; ln -s 
../../../nsprpub/pr/include/./pripcsem.h

dylang@shadowgate:/builds/mozilla/dist/include/nspr$ ls -l pripcsem.h
lrwxrwxrwx    1 dylang   web           234 Jan 14 14:32 pripcsem.h -> 
../../../nsprpub/pr/include/./pripcsem.h_PC_PRIO_IO:11,_PC_SOCK_MAXBUF:12,_PC_FILESIZEBITS:13,_PC_REC_INCR_XFER_SIZE:14,_PC_REC_MAX_XFER_SIZE:15,_PC_REC_MIN_XFER_SIZE:16,_PC_REC_XFER_ALIGN:17,_PC_ALLOC_SIZE_MIN:18,_PC_SYMLINK_MAX:19,;

Aha!  NFSv3 somehow is not handling this well at all.

Suggestions?

(Note: please CC me as I'm not on the list; BCC will bounce)
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Re: Linux 2.4 NFS bug (annoying sylmlinx breakage)

[Andreas Dilger]

On Jan 14, 2002  14:50 -0600, Dylan Griffiths wrote:
> I've noticed this bug before.  Between two hosts on a 100Mbps switched lan, 
> symlinks are trashed into garbage.  Based on the output. I'm guessing a 
> string loses its null somewhere.
> 
> Client is 2.4.14.  Server is 2.4.10.  Server has RAID 5 IDE softraid and 
> an hpt370 driver patch provided by Tim Hockin to fix the deadlocks and 
> oopsies of the hpt366 driver on my hpt370.

Upgrade your kernel before reporting such bugs.  I'm pretty sure it has
already been fixed.  Something about the NFSv3 calling an inappropriate
(but similarly named) function in the symlink path.

Cheers, Andreas
--
Andreas Dilger
http://sourceforge.net/projects/ext2resize/
http://www-mddsp.enel.ucalgary.ca/People/adilger/

Re: Linux 2.4 NFS bug (annoying sylmlinx breakage)

[Dylan Griffiths]

Andreas Dilger wrote:
> Upgrade your kernel before reporting such bugs.  I'm pretty sure it has
> already been fixed.  Something about the NFSv3 calling an inappropriate
> (but similarly named) function in the symlink path.

I've looked at the 2.4.14 nfs fs code as it seemed client side.


         /* We place the length at the beginning of the page,
          * in host byte order, followed by the string.  The
          * XDR response verification will NULL terminate it.
          */


I'm guessing nfs3xdr.c does not have this behaviour the code relies on.  I 
will grab 2.4.17 and see of the code/behaviour is different.

-- 
     www.kuro5hin.org -- technology and culture, from the trenches.
                          -=-=-=-=-=-
Those that give up liberty to obtain safety deserve neither.
  -- Benjamin Franklin
   http://www.zdnet.com/zdnn/stories/news/0,4586,2812463,00.html
   http://slashdot.org/article.pl?sid=01/09/16/1647231
                          -=-=-=-=-=-