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

[chas williams - CONTRACTOR]

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,