[Unionfs] kernel BUG at fs/unionfs/fanout.h:128!

[Phillip Lougher]

On 9/20/07, Erez Zadok <ezk at cs.sunysb.edu> wrote:

> Oliver, I'm pretty certain that your patch is correct.  I've fixed a similar
> bug elsewhere in the code not too long ago.
>

Hi Erez,

We were hitting this issue in Canonical, after debugging I discovered
this to be always caused by unionfs_flush calling
unionfs_copy_attr_times on the parent dentry of the dentry being
flushed.  Adding a check for negative parent dentry ibstart fixed the
problem for us.

-       unionfs_copy_attr_times(dentry->d_parent->d_inode);
+        if(ibstart(dentry->d_parent->d_inode) < 0) {
+                printk(KERN_WARNING "unionfs_flush: skipping
unionfs_copy_attr_times for parent, parent has no branches!\n");
+        } else
+               unionfs_copy_attr_times(dentry->d_parent->d_inode);



Phillip