[Andrew Morton - Sat, Jun 02, 2007 at 03:49:42PM -0700]
| On Sun, 3 Jun 2007 00:01:46 +0400 Cyrill Gorcunov <[EMAIL PROTECTED]> wrote:
|
| > [Andrew Morton - Sat, Jun 02, 2007 at 12:16:16PM -0700]
| > [...snip...]
| > |
| > | No, the problem is that the patch caused the kernel to take inode_lock
| > | within the newly-added drop_inode(), btu drop_inode() is already called
| > | under inode_lock.
| > |
| > | It has nothing to do with lock_kernel() and it has nothing to do with
| > | sleeping.
| > |
| >
| > Andrew, the only call that could leading to subseq. inode_lock lock
| > is mark_inode_dirty() I guess (and that is snown by Eric's dump)
| > but as I shown you in my dbg print without SMP it's OK. So
| > is it SMP who lead to lock? How it depends on it? (I understand
| > that is a stupid question for you but if you have time explain
| > me this please ;)
| >
|
| When CONFIG_SMP=n, spin_lock() is a no-op. (Except with CONFIG_PREEMPT=y,
| in which case spin_lock() will disable kernel preemption on SMP and non-SMP
| kernels)
|
| When CONFIG_SMP=y, spin_lock() really does take a lock. But if this thread
| already holds this lock, we'll deadlock.
|
Thanks, Andrew. So the reason that raises lock problem is the calling of
mark_inode_dirty() inside drop_inode() (by indirection). And I see two way
of solution:
- or check for inode->i_count at each mark_inode_dirty that being called
after drop_inode
if (inode->i_count > 0)
mark_inode_dirty()
- or wrap mark_inode_dirty as
udf_mark_inode_dirty()
{
if (inode->i_count > 0)
mark_inode_dirty();
}
and replace all mark_inode_dirty -> udf_mark_inode_dirty
Your thoughts?
Cyrill
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