[Pvfs2-developers] patch: namei bug fixes

[Phil Carns]

I am sending this patch in a separate email because it may need some 
discussion to hash out.  Sometime in the past several months, the 
pvfs2_lookup() function in namei.c changed (I think along with something 
not directly related, but I don't recall exactly what happened now).

This change caused several directory related bugs to show up for us on 
2.4 and 2.6 kernels.  The 2.4 one was more severe, though, because it 
caused a kernel panic.  It could be triggered by the "rename01" test in 
LTP, or by the following manual steps:

[root at rhel3 pvfs2]# mkdir testdir
[root at rhel3 pvfs2]# cd testdir
[root at rhel3 testdir]# mkdir dir1
[root at rhel3 testdir]# mv dir1 dir2
[root at rhel3 testdir]# ls -alh
total 12K
drwxr-xr-x    1 root     root         4.0K Dec  1 12:18 .
drwxrwxrwt    1 root     root         4.0K Dec  1 12:17 ..
drwxr-xr-x    1 root     root         4.0K Dec  1 12:17 dir2
[root at centos-rhel3 testdir]# rm dir2
<crash>

... so it had something to do with removing a directory that had 
previously been renamed.

At any rate, I don't know enough about dentries and inodes anymore to 
truly understand the old logic that used to work or the newer logic that 
causes us problems.  This patch just naively reverts some of the logic 
in namei.c to the point that it works again for us (without changing 
anything else that was in that set of commits).  With this in place, we 
don't see any more test case failures or kernel panics on 2.6 or 2.4.

We have been using this patch for several months with success, but it 
would probably be a good idea for someone more familiar with this code 
to look at the change more carefully.

-Phil
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