[OpenAFS-devel] AFS 1.3.82 failing in kernel, tracing back to link_path_walk/dput/iput.

[C. Alex. North-Keys]

This delightfully short patch appears to completely address both the 
obvious issue as well as the inability to shutdown OpenAFS.  I applaud 
you :-)

I've tested this both with and without the --enable-namei-fileserver 
option, and both appear to be working fine.

Is it likely that this will be part of version 1.3.84+?

Thanks again!

chas williams - CONTRACTOR wrote:
> In message <OF51AE5234.55C8166D-ONC1257015.004C3357-C1257015.004C4D98@de.ibm.co
> m>,Sven Oehme writes:
> 
>>       wake_up_inode(inode);
>>       if (inode->i_state != I_CLEAR)
>>line 1023 ---->>                BUG();
>>       destroy_inode(inode);
>>}
> 
> 
> i thought it might be.  it looks like afs might be racing to get a
> vnode from the lru and isnt "respecting" the i_state flags.  once
> osi_clear_inode() makes the vnode inactive, it is ready for use 
> again.  we only hold GLOCK during osi_clear_inode, but a quick
> fix might hold GLOCK during more of drop operation to keep other
> parts of afs from grabbing a vnode until its truly been recycled.
> 
> try this patch.  note that you should not hold the GLOCK before entering
> generic_delete_inode() since inode_lock (spinlock) is already held at
> this point.  so afs_delete_inode() does it normal GLOCK but the GUNLOCK
> is moved until after generic_delete_inode() is finished.
> 
> i havent seen this race but my machine is rather slow (dual 1Ghz).
> 
> Index: src/afs/LINUX/osi_vfsops.c
> ===================================================================
> RCS file: /cvs/openafs/src/afs/LINUX/osi_vfsops.c,v
> retrieving revision 1.32
> diff -u -u -r1.32 osi_vfsops.c
> --- src/afs/LINUX/osi_vfsops.c	11 Mar 2005 04:35:42 -0000	1.32
> +++ src/afs/LINUX/osi_vfsops.c	3 Jun 2005 14:15:44 -0000
> @@ -289,6 +287,14 @@
>  
>  
>  static void
> +afs_drop_inode(struct inode *ip)
> +{
> +	generic_delete_inode(ip);
> +	AFS_GUNLOCK();		/* locked by afs_delete_inode() */
> +}
> +
> +
> +static void
>  afs_destroy_inode(struct inode *ip)
>  {
>      ip->i_state = 0;
> @@ -305,13 +311,15 @@
>  static void
>  afs_delete_inode(struct inode *ip)
>  {
> -#ifdef AFS_LINUX26_ENV
> +#if defined(AFS_LINUX26_ENV)
> +    AFS_GLOCK();		/* after spin_unlock(inode_lock) */
>      put_inode_on_dummy_list(ip);
> -#endif
> -
> +    osi_clear_inode(ip);
> +#else
>      AFS_GLOCK();
>      osi_clear_inode(ip);
>      AFS_GUNLOCK();
> +#endif
>  }
>  
>  
> @@ -404,7 +414,7 @@
>  
>  struct super_operations afs_sops = {
>  #if defined(AFS_LINUX26_ENV)
> -  .drop_inode =		generic_delete_inode,
> +  .drop_inode =		afs_drop_inode,
>    .destroy_inode =	afs_destroy_inode,
>  #endif
>    .delete_inode =	afs_delete_inode,

-- 
C. Alex. North-Keys
CatalisHealth, Inc.
erlkonig@TheCatalis.com
512.874.7666