[DLM] fix resend rcom lock [2/54]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



>From 3f75e071fc3e5479800614656492230a1ce50182 Mon Sep 17 00:00:00 2001
From: David Teigland <[email protected]>
Date: Wed, 13 Dec 2006 10:36:37 -0600
Subject: [PATCH] [DLM] fix resend rcom lock

There's a chance the new master of resource hasn't learned it's the new
master before another node sends it a lock during recovery.  The node
sending the lock needs to resend if this happens.

- A sends a master lookup for resource R to C
- B sends a master lookup for resource R to C
- C receives A's lookup, assigns A to be master of R and
  sends a reply back to A
- C receives B's lookup and sends a reply back to B saying
  that A is the master
- B receives lookup reply from C and sends its lock for R to A
- A receives lock from B, doesn't think it's the master of R
  and sends an error back to B
- A receives lookup reply from C and becomes master of R
- B gets error back from A and resends its lock back to A
  (this resending is what this patch does)
- A receives lock from B, it now sees it's the master of R
  and takes the lock

Signed-off-by: David Teigland <[email protected]>
Signed-off-by: Steven Whitehouse <[email protected]>

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 30878de..69ada58 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -3571,6 +3571,14 @@ int dlm_recover_process_copy(struct dlm_ls *ls, struct dlm_rcom *rc)
 	lock_rsb(r);
 
 	switch (error) {
+	case -EBADR:
+		/* There's a chance the new master received our lock before
+		   dlm_recover_master_reply(), this wouldn't happen if we did
+		   a barrier between recover_masters and recover_locks. */
+		log_debug(ls, "master copy not ready %x r %lx %s", lkb->lkb_id,
+			  (unsigned long)r, r->res_name);
+		dlm_send_rcom_lock(r, lkb);
+		goto out;
 	case -EEXIST:
 		log_debug(ls, "master copy exists %x", lkb->lkb_id);
 		/* fall through */
@@ -3585,7 +3593,7 @@ int dlm_recover_process_copy(struct dlm_ls *ls, struct dlm_rcom *rc)
 	/* an ack for dlm_recover_locks() which waits for replies from
 	   all the locks it sends to new masters */
 	dlm_recovered_lock(r);
-
+ out:
 	unlock_rsb(r);
 	put_rsb(r);
 	dlm_put_lkb(lkb);
-- 
1.4.4.2



-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux