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-rw-r--r--fs/dlm/member.c41
1 files changed, 27 insertions, 14 deletions
diff --git a/fs/dlm/member.c b/fs/dlm/member.c
index d09977528f69..e9cdcab306e2 100644
--- a/fs/dlm/member.c
+++ b/fs/dlm/member.c
@@ -18,10 +18,6 @@
#include "rcom.h"
#include "config.h"
-/*
- * Following called by dlm_recoverd thread
- */
-
static void add_ordered_member(struct dlm_ls *ls, struct dlm_member *new)
{
struct dlm_member *memb = NULL;
@@ -250,18 +246,30 @@ int dlm_recover_members(struct dlm_ls *ls, struct dlm_recover *rv, int *neg_out)
return error;
}
-/*
- * Following called from lockspace.c
- */
+/* Userspace guarantees that dlm_ls_stop() has completed on all nodes before
+ dlm_ls_start() is called on any of them to start the new recovery. */
int dlm_ls_stop(struct dlm_ls *ls)
{
int new;
/*
- * A stop cancels any recovery that's in progress (see RECOVERY_STOP,
- * dlm_recovery_stopped()) and prevents any new locks from being
- * processed (see RUNNING, dlm_locking_stopped()).
+ * Prevent dlm_recv from being in the middle of something when we do
+ * the stop. This includes ensuring dlm_recv isn't processing a
+ * recovery message (rcom), while dlm_recoverd is aborting and
+ * resetting things from an in-progress recovery. i.e. we want
+ * dlm_recoverd to abort its recovery without worrying about dlm_recv
+ * processing an rcom at the same time. Stopping dlm_recv also makes
+ * it easy for dlm_receive_message() to check locking stopped and add a
+ * message to the requestqueue without races.
+ */
+
+ down_write(&ls->ls_recv_active);
+
+ /*
+ * Abort any recovery that's in progress (see RECOVERY_STOP,
+ * dlm_recovery_stopped()) and tell any other threads running in the
+ * dlm to quit any processing (see RUNNING, dlm_locking_stopped()).
*/
spin_lock(&ls->ls_recover_lock);
@@ -271,8 +279,14 @@ int dlm_ls_stop(struct dlm_ls *ls)
spin_unlock(&ls->ls_recover_lock);
/*
+ * Let dlm_recv run again, now any normal messages will be saved on the
+ * requestqueue for later.
+ */
+
+ up_write(&ls->ls_recv_active);
+
+ /*
* This in_recovery lock does two things:
- *
* 1) Keeps this function from returning until all threads are out
* of locking routines and locking is truely stopped.
* 2) Keeps any new requests from being processed until it's unlocked
@@ -284,9 +298,8 @@ int dlm_ls_stop(struct dlm_ls *ls)
/*
* The recoverd suspend/resume makes sure that dlm_recoverd (if
- * running) has noticed the clearing of RUNNING above and quit
- * processing the previous recovery. This will be true for all nodes
- * before any nodes start the new recovery.
+ * running) has noticed RECOVERY_STOP above and quit processing the
+ * previous recovery.
*/
dlm_recoverd_suspend(ls);
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