Re: Possible bug in ext3 filesystem

[Theodore Tso <tytso@mit.edu>]

On Thu, Jan 04, 2007 at 12:34:16PM +0100, Jens Nie wrote:
> 
> I think i found a bug in the ext3 filesystem. It deals with 
> dereferencing symlinks. I have installed a fresh openSUSE 10.2 on an
> ext3 filesystem.
> After that i wanted to include some selfmade LaTeX-classes by creating 
> a symlink within /usr/share/texmf/tex/latex to the directory 
> containing the class. texhash lists the new link within 
> /usr/share/texmf/ls-R. However the complete content of the classes 
> directory is missing. File and directory permissions are OK. I suspect 
> that the dereferencing of symlinks to the target directory does not 
> work on ext3. To check that i tested an older SuSE Installation with 
> reiserfs, which works as expected. Another test i made was creating an 
> ext3 fs, xfs and reiserfs on a loopback device. Within this test 
> filesystem that i mounted temporarily to /mnt i created a symlink to 
> /usr. Issuing the command ls -LRa, which is exactly what texhash is 
> using and should dereference the link to /usr did not recursively list 
> the contents of /usr on the ext3 filesystem whereas it did on the
> reiserfs and xfs.

It works for me.  Using Ubuntu Edgy userspace with a 2.6.19-rc3
kernel on a T60p laptop:

						- Ted

Script started on Thu 04 Jan 2007 12:36:43 PM EST
Top-level shell (parent script)
Using ssh-agent pid 6342
<tytso.root@candygram>	{/home/tytso}
499# dd if=/dev/zero of=/var/tmp/test.img bs=1k count=30000
30000+0 records in
30000+0 records out
30720000 bytes (31 MB) copied, 1.28516 seconds, 23.9 MB/s
<tytso.root@candygram>	{/home/tytso}
500# mke2fs -j /var/tmp/test.img
mke2fs 1.40-WIP (14-Nov-2006)
/var/tmp/test.img is not a block special device.
Proceed anyway? (y,n) y
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
7520 inodes, 30000 blocks
1500 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=30932992
4 block groups
8192 blocks per group, 8192 fragments per group
1880 inodes per group
Superblock backups stored on blocks: 
	8193, 24577

Writing inode tables: done                            
Creating journal (1400 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 34 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.
<tytso.root@candygram>	{/home/tytso}
501# mount -t ext3 -o loop /var/tmp/test.img /mnt
<tytso.root@candygram>	{/home/tytso}
502# cd /mnt
<tytso.root@candygram>	{/mnt}
503# ln -s /tmp foo
<tytso.root@candygram>	{/mnt}
504# ls -l
total 12
 0 lrwxrwxrwx 1 root root     4 2007-01-04 12:38 foo -> /tmp/
12 drwx------ 2 root root 12288 2007-01-04 12:37 lost+found/
<tytso.root@candygram>	{/mnt}
505# ls -LRa /mnt
/mnt:
total 17
 1 ./   4 ../   0 foo/	12 lost+found/

/mnt/foo:
total 33624
    0 ./		      8 IDB46835.DTF	     4 play.pls
    4 ../		     32 IDB66197.DTF	     0 plugtmp/
 6440 APC Flyer_embd.ppt     32 IDB77400.DTF	    56 repair.pdf
26808 dumpe2fs.txt.bz2	     32 IDB78728.DTF	    20 Rt-Issues-1.ods
    0 .esd-15806/	     32 IDB96845.DTF	     0 ssh-CWzKqE6724/
    0 .exchange-tytso/	      0 keyring-hoWMU3/      0 ssh-PtOxzg6309/
    0 gconfd-tytso/	      0 mapping-tytso=	     0 ssh-TnSaM10059/
    0 .gdm_socket=	      0 notesFCB315/	     0 ssh-Zjhueb6724/
    0 .ICE-unix/	      0 orbit-tytso/	     0 ssh-ZueXS10264/
   32 IDB07883.DTF	      4 play-1.pls	     0 virtual-tytso.m02ZFH/
   32 IDB09374.DTF	      4 play-2.pls	     0 .wine-15806/
   32 IDB34926.DTF	      4 play-3.pls	     4 .X0-lock
   40 IDB44293.DTF	      4 play-4.pls	     0 .X11-unix/

/mnt/foo/.esd-15806:
total 0
0 ./  0 ../  0 socket=

/mnt/foo/.exchange-tytso:
total 0
0 ./  0 ../

/mnt/foo/gconfd-tytso:
total 0
0 ./  0 ../  0 lock/

/mnt/foo/gconfd-tytso/lock:
total 4
0 ./  0 ../  4 ior*

/mnt/foo/.ICE-unix:
total 0
0 ./  0 ../  0 6724=

/mnt/foo/keyring-hoWMU3:
total 0
0 ./  0 ../  0 socket=

/mnt/foo/notesFCB315:
total 512
  0 ./	  0 ../  504 ~editclp.ncf    4 ~notetmp.reg    4 ~notetp2.reg

/mnt/foo/orbit-tytso:
total 4
0 ./				    0 linc-1b16-0-7215ae8e714e5=
0 ../				    0 linc-1b38-0-164e0af7b7ab1=
0 bonobo-activation-register.lock*  0 linc-1b7a-0-23ef1182722fa=
4 bonobo-activation-server-ior	    0 linc-1bad-0-510bba9c63bb6=
0 linc-1a44-0-466fcbd5aa1f0=	    0 linc-1bff-0-5f07b0c6e3793=
0 linc-1a92-0-4e186b54931f9=	    0 linc-1c05-0-3427276e3f87c=
0 linc-1aa5-0-1f23e56b70d97=	    0 linc-34e6-0-5853523bb2721=
0 linc-1acc-0-7fbb2ca661716=	    0 linc-4269-0-3a34f2c58b987=
0 linc-1ad1-0-5db9c951c0cc9=	    0 linc-5492-0-d435cecb77c5=
0 linc-1ad4-0-1aac39888363d=	    0 linc-57fc-0-33e090d41719a=
0 linc-1ae6-0-7a50f3e07932f=	    0 linc-f1f-0-68984f4a27444=
0 linc-1ae8-0-684e70a345d5=	    0 linc-f2d-0-68984f4a73a2d=
0 linc-1aea-0-7a50f3e0d46f4=	    0 linc-f2f-0-68984f4a8a1f7=
0 linc-1af4-0-73566ae82dc75=	    0 linc-f31-0-68984f4a91497=
0 linc-1b0d-0-44885fa524551=	    0 linc-f40-0-1f1d2cf4f67e=
0 linc-1b12-0-7215ae8126f2e=

/mnt/foo/plugtmp:
total 0
0 ./  0 ../

/mnt/foo/ssh-CWzKqE6724:
total 0
0 ./  0 ../  0 agent.6724=

/mnt/foo/ssh-PtOxzg6309:
total 0
0 ./  0 ../  0 agent.6309=

/mnt/foo/ssh-TnSaM10059:
total 0
0 ./  0 ../  0 agent.10059=

/mnt/foo/ssh-Zjhueb6724:
total 0
0 ./  0 ../  0 agent.6724=

/mnt/foo/ssh-ZueXS10264:
total 0
0 ./  0 ../  0 agent.10264=

/mnt/foo/virtual-tytso.m02ZFH:
total 0
0 ./  0 ../

/mnt/foo/.wine-15806:
total 0
0 ./  0 ../  0 cxoffice-wine.lock  0 server-802-71e6d9/

/mnt/foo/.wine-15806/server-802-71e6d9:
total 0
0 ./  0 ../  0 lock  0 socket=	0 vwin32.vxd

/mnt/foo/.X11-unix:
total 0
0 ./  0 ../  0 X0=

/mnt/lost+found:
total 13
12 ./   1 ../
<tytso.root@candygram>	{/mnt}
506# 
Script done on Thu 04 Jan 2007 12:38:32 PM EST