[DLM] fix stopping unstarted recovery [43/70]

From: Steven Whitehouse
Date: Thu Nov 30 2006 - 07:33:32 EST


>From 2cdc98aaf072d573df10c503d3b3b0b74e2a6d06 Mon Sep 17 00:00:00 2001
From: David Teigland <teigland@xxxxxxxxxx>
Date: Tue, 31 Oct 2006 11:56:08 -0600
Subject: [PATCH] [DLM] fix stopping unstarted recovery

Red Hat BZ 211914

When many nodes are joining a lockspace simultaneously, the dlm gets a
quick sequence of stop/start events, a pair for adding each node.
dlm_controld in user space sends dlm_recoverd in the kernel each stop and
start event. dlm_controld will sometimes send the stop before
dlm_recoverd has had a chance to take up the previously queued start. The
stop aborts the processing of the previous start by setting the
RECOVERY_STOP flag. dlm_recoverd is erroneously clearing this flag and
ignoring the stop/abort if it happens to take up the start after the stop
meant to abort it. The fix is to check the sequence number that's
incremented for each stop/start before clearing the flag.

Signed-off-by: David Teigland <teigland@xxxxxxxxxx>
Signed-off-by: Steven Whitehouse <swhiteho@xxxxxxxxxx>
---
fs/dlm/recoverd.c | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/fs/dlm/recoverd.c b/fs/dlm/recoverd.c
index 4a1d602..6e4ee94 100644
--- a/fs/dlm/recoverd.c
+++ b/fs/dlm/recoverd.c
@@ -219,6 +219,10 @@ static int ls_recover(struct dlm_ls *ls,
return error;
}

+/* The dlm_ls_start() that created the rv we take here may already have been
+ stopped via dlm_ls_stop(); in that case we need to leave the RECOVERY_STOP
+ flag set. */
+
static void do_ls_recovery(struct dlm_ls *ls)
{
struct dlm_recover *rv = NULL;
@@ -226,7 +230,8 @@ static void do_ls_recovery(struct dlm_ls
spin_lock(&ls->ls_recover_lock);
rv = ls->ls_recover_args;
ls->ls_recover_args = NULL;
- clear_bit(LSFL_RECOVERY_STOP, &ls->ls_flags);
+ if (rv && ls->ls_recover_seq == rv->seq)
+ clear_bit(LSFL_RECOVERY_STOP, &ls->ls_flags);
spin_unlock(&ls->ls_recover_lock);

if (rv) {
--
1.4.1



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