cluster/ec: Rebalance hangs during rename

Problem:
During the rename of a particular file (ec
is holding blocking inodelk on the parent
directory), if the rename of another file
under the same directory comes. EC does not
release the lock and goes ahead and renames
the "new" file with the "already held lock".

That causes rebalance process to be blocked
on a lock which has been acquired by rename.

Solution:
While rename fop comes, ec takes blocking inodelk
on old and new parent of the file. Before releasing,
every lock held by ec, it waits for some "time" to
see if that lock can be reused by the next fop.
If within this "time" some other request comes,
it releases this lock based on condition
"lock count > 1"

To get this "lock count" for rename fop, we have
implemented "pl_rename" in feature/lock. Also,
on ec side, changed the condition to release the lock
based on the type of fop and old and new parent
directories.

Change-Id: I979dbab1185df962e8f305a6074ae1186ffe7db0
Bug: 1304988
Signed-off-by: Ashish Pandey <aspandey@redhat.com>
Reviewed-on: http://review.gluster.org/13460
Smoke: Gluster Build System <jenkins@build.gluster.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Reviewed-by: Krutika Dhananjay <kdhananj@redhat.com>

1 files changed, 64 insertions, 0 deletions

diff --git a/xlators/features/locks/src/pl-messages.h b/xlators/features/locks/src/pl-messages.h
new file mode 100644
index 00000000000..45c8873ecb4
--- /dev/null
+++ b/xlators/features/locks/src/pl-messages.h
@@ -0,0 +1,64 @@
+/*
+  Copyright (c) 2016 Red Hat, Inc. <http://www.redhat.com>
+  This file is part of GlusterFS.
+
+  This file is licensed to you under your choice of the GNU Lesser
+  General Public License, version 3 or any later version (LGPLv3 or
+  later), or the GNU General Public License, version 2 (GPLv2), in all
+  cases as published by the Free Software Foundation.
+*/
+
+#ifndef _PL_MESSAGES_H_
+#define _PL_MESSAGES_H_
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#include "glfs-message-id.h"
+
+/*! \file pl-messages.h
+ *  \brief Locks log-message IDs and their descriptions
+ */
+
+/* NOTE: Rules for message additions
+ * 1) Each instance of a message is _better_ left with a unique message ID, even
+ *    if the message format is the same. Reasoning is that, if the message
+ *    format needs to change in one instance, the other instances are not
+ *    impacted or the new change does not change the ID of the instance being
+ *    modified.
+ * 2) Addition of a message,
+ *       - Should increment the GLFS_NUM_MESSAGES
+ *       - Append to the list of messages defined, towards the end
+ *       - Retain macro naming as glfs_msg_X (for redability across developers)
+ * NOTE: Rules for message format modifications
+ * 3) Check acorss the code if the message ID macro in question is reused
+ *    anywhere. If reused then then the modifications should ensure correctness
+ *    everywhere, or needs a new message ID as (1) above was not adhered to. If
+ *    not used anywhere, proceed with the required modification.
+ * NOTE: Rules for message deletion
+ * 4) Check (3) and if used anywhere else, then cannot be deleted. If not used
+ *    anywhere, then can be deleted, but will leave a hole by design, as
+ *    addition rules specify modification to the end of the list and not filling
+ *    holes.
+ */
+
+#define GLFS_PL_COMP_BASE       GLFS_MSGID_COMP_PL
+#define GLFS_NUM_MESSAGES       1
+#define GLFS_MSGID_END          (GLFS_PL_COMP_BASE + GLFS_NUM_MESSAGES + 1)
+/* Messaged with message IDs */
+#define glfs_msg_start_x GLFS_PL_COMP_BASE, "Invalid: Start of messages"
+/*------------*/
+
+/*!
+ * @messageid
+ * @diagnosis
+ * @recommendedaction
+ */
+#define PL_MSG_LOCK_NUMBER           (GLFS_PL_COMP_BASE + 1)
+
+/*------------*/
+#define glfs_msg_end_x GLFS_MSGID_END, "Invalid: End of messages"
+
+#endif /* !_PL_MESSAGES_H_ */