From 5fe6f031d9a21a935f0ef1b1fbdb314b53f2199f Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Thu, 10 Jul 2014 15:54:02 +1000
Subject: [PATCH] mdmon: allow prepare_update to report failure.

If 'prepare_update' fails for some reason there is little
point continuing on to 'process_update'.
For now only malloc failures are caught, but other failures
will be considered in future.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 managemon.c   | 3 ++-
 mdadm.h       | 5 ++++-
 super-ddf.c   | 8 +++++---
 super-intel.c | 9 +++++----
 4 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/managemon.c b/managemon.c
index 5f7e2ced..1c9eccc4 100644
--- a/managemon.c
+++ b/managemon.c
@@ -819,7 +819,8 @@ static void handle_message(struct supertype *container, struct metadata_update *
 		mu->space_list = NULL;
 		mu->next = NULL;
 		if (container->ss->prepare_update)
-			container->ss->prepare_update(container, mu);
+			if (!container->ss->prepare_update(container, mu))
+				free_updates(&mu);
 		queue_metadata_update(mu);
 	}
 }
diff --git a/mdadm.h b/mdadm.h
index 914d67cd..02a9288d 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -929,7 +929,10 @@ extern struct superswitch {
 	void (*sync_metadata)(struct supertype *st);
 	void (*process_update)(struct supertype *st,
 			       struct metadata_update *update);
-	void (*prepare_update)(struct supertype *st,
+	/* Prepare updates allocates extra memory that might be
+	 * needed.  If the update cannot be understood,  return 0.
+	 */
+	int (*prepare_update)(struct supertype *st,
 			       struct metadata_update *update);
 
 	/* activate_spare will check if the array is degraded and, if it
diff --git a/super-ddf.c b/super-ddf.c
index ab9fc46f..1e43ca26 100644
--- a/super-ddf.c
+++ b/super-ddf.c
@@ -4906,8 +4906,8 @@ static void ddf_process_update(struct supertype *st,
 	/* case DDF_SPARE_ASSIGN_MAGIC */
 }
 
-static void ddf_prepare_update(struct supertype *st,
-			       struct metadata_update *update)
+static int ddf_prepare_update(struct supertype *st,
+			      struct metadata_update *update)
 {
 	/* This update arrived at managemon.
 	 * We are about to pass it to monitor.
@@ -4922,15 +4922,17 @@ static void ddf_prepare_update(struct supertype *st,
 				   offsetof(struct vcl, conf)
 				   + ddf->conf_rec_len * 512) != 0) {
 			update->space = NULL;
-			return;
+			return 0;
 		}
 		vcl = update->space;
 		vcl->conf.sec_elmnt_count = conf->sec_elmnt_count;
 		if (alloc_other_bvds(ddf, vcl) != 0) {
 			free(update->space);
 			update->space = NULL;
+			return 0;
 		}
 	}
+	return 1;
 }
 
 /*
diff --git a/super-intel.c b/super-intel.c
index 7734bde4..2547b4a4 100644
--- a/super-intel.c
+++ b/super-intel.c
@@ -8607,8 +8607,8 @@ static void imsm_process_update(struct supertype *st,
 
 static struct mdinfo *get_spares_for_grow(struct supertype *st);
 
-static void imsm_prepare_update(struct supertype *st,
-				struct metadata_update *update)
+static int imsm_prepare_update(struct supertype *st,
+			       struct metadata_update *update)
 {
 	/**
 	 * Allocate space to hold new disk entries, raid-device entries or a new
@@ -8828,6 +8828,7 @@ static void imsm_prepare_update(struct supertype *st,
 		else
 			super->next_buf = NULL;
 	}
+	return 1;
 }
 
 /* must be called while manager is quiesced */
@@ -9716,8 +9717,8 @@ static void imsm_update_metadata_locally(struct supertype *st,
 	mu.space = NULL;
 	mu.space_list = NULL;
 	mu.next = NULL;
-	imsm_prepare_update(st, &mu);
-	imsm_process_update(st, &mu);
+	if (imsm_prepare_update(st, &mu))
+		imsm_process_update(st, &mu);
 
 	while (mu.space_list) {
 		void **space = mu.space_list;
-- 
2.39.2