<div dir="ltr"><br><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Jun 5, 2014 at 7:52 PM, Pranith Kumar Karampuri <span dir="ltr"><<a href="mailto:pkarampu@redhat.com" target="_blank">pkarampu@redhat.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"><div><div class="h5"><blockquote type="cite"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div><br>
</div>
<div>This sounds a bit complicated. I think there
is a much simpler solution:</div>
<div><br>
</div>
<div>- First, make update_refkeeper() check for
blocked locks (which I mentioned as "optional" previously)</div>
<div><br>
</div>
<div>- Make grant_blocked_locks() double up and do
the job of update_refkeeper() internally.</div>
<div><br>
</div>
<div>Something which looks like this:</div>
<div><br>
</div>
<div>
<div>
<div>diff --git a/xlators/features/locks/src/common.c
b/xlators/features/locks/src/common.c</div>
<div>index f6c71c1..38df385 100644</div>
<div>--- a/xlators/features/locks/src/common.c</div>
<div>+++ b/xlators/features/locks/src/common.c</div>
<div>@@ -126,8 +126,14 @@ __pl_inode_is_empty
(pl_inode_t *pl_inode)</div>
<div> if (!list_empty
(&dom->entrylk_list))</div>
<div> is_empty = 0;</div>
<div> </div>
<div>+ if (!list_empty
(&dom->blocked_entrylks))</div>
<div>+ is_empty = 0;</div>
<div>+</div>
<div> if (!list_empty
(&dom->inodelk_list))</div>
<div> is_empty = 0;</div>
<div>+</div>
<div>+ if (!list_empty
(&dom->blocked_inodelks))</div>
<div>+ is_empty = 0;</div>
<div> }</div>
<div> </div>
<div>
return is_empty;</div>
<div>@@ -944,12 +950,18 @@ grant_blocked_locks (xlator_t
*this, pl_inode_t *pl_inode)</div>
<div> struct list_head granted_list;</div>
<div> posix_lock_t *tmp = NULL;</div>
<div> posix_lock_t *lock = NULL;</div>
<div>+ inode_t *unref = NULL;</div>
<div> </div>
<div> INIT_LIST_HEAD (&granted_list);</div>
<div> </div>
<div> pthread_mutex_lock
(&pl_inode->mutex);</div>
<div> {</div>
<div> __grant_blocked_locks (this,
pl_inode, &granted_list);</div>
<div>+</div>
<div>+ if (__pl_inode_is_empty (pl_inode)
&& pl_inode->refkeeper) {</div>
<div>
+ unref =
pl_inode->refkeeper;</div>
<div>+ pl_inode->refkeeper =
NULL;</div>
<div>+ }</div>
<div> }</div>
<div> pthread_mutex_unlock
(&pl_inode->mutex);</div>
<div> </div>
<div>@@ -965,6 +977,9 @@ grant_blocked_locks (xlator_t
*this, pl_inode_t *pl_inode)</div>
<div> GF_FREE (lock);</div>
<div> }</div>
<div> </div>
<div>+ if (unref)</div>
<div>+ inode_unref (unref);</div>
<div>+</div>
<div> return;</div>
<div> }</div>
</div>
<div><br>
</div>
</div>
</div>
</div>
</div>
</blockquote>
<blockquote type="cite">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">
<div>
<div><br>
</div>
<div>This should make pl_disconnect_cbk() pretty
much race free w.r.t refkpeer. Thoughts?</div>
</div>
</div>
</div>
</div>
</blockquote></div></div>
Lets say C1 is doing pl_inodelk_client_cleanup. After the second
for-loop(All granted and blocked locks are out of the domain) if an
unlock on the final granted lock on that inode from client C2
completes, refkeeper would be set to NULL and unrefed leading to
zero refs on that inode i.e. pl_forget will also happen. In 3rd
for-loop pl_inode is already freed and leads to free'd memory access
and will crash.</div></blockquote><div><br></div><div><br></div><div>We also need:</div><div><br></div><pre style="color:rgb(0,0,0)">diff --git a/xlators/features/locks/src/inodelk.c b/xlators/features/locks/src/inodelk.c
index c76cb7f..2aceb8a 100644
--- a/xlators/features/locks/src/inodelk.c
+++ b/xlators/features/locks/src/inodelk.c
@@ -494,13 +494,13 @@ pl_inodelk_client_cleanup (xlator_t *this, pl_ctx_t *ctx)
dom = get_domain (pl_inode, l->volume);
- grant_blocked_inode_locks (this, pl_inode, dom);
-
pthread_mutex_lock (&pl_inode->mutex);
{
__pl_inodelk_unref (l);
}
pthread_mutex_unlock (&pl_inode->mutex);
+
+ grant_blocked_inode_locks (this, pl_inode, dom);
}
</pre><div><span style="color:rgb(0,0,0)"> return 0;</span></div><div><br></div><div>Missed this in the last patch. </div></div></div></div>