[PATCH 13/20] cache: return results of a cache flush

["Darrick J. Wong" <djwong@xxxxxxxxxx>]

From: Darrick J. Wong <djwong@xxxxxxxxxx>

Modify cache_flush to return whether or not there were errors whilst
flushing the cache.

Signed-off-by: "Darrick J. Wong" <djwong@xxxxxxxxxx>
---
 lib/support/cache.h |    4 ++--
 lib/support/cache.c |   11 +++++++----
 2 files changed, 9 insertions(+), 6 deletions(-)


diff --git a/lib/support/cache.h b/lib/support/cache.h
index e8f1c82ef7869c..8d39ca5c02a285 100644
--- a/lib/support/cache.h
+++ b/lib/support/cache.h
@@ -58,7 +58,7 @@ typedef void *cache_key_t;
 
 typedef void (*cache_walk_t)(struct cache *c, struct cache_node *cn, void *d);
 typedef struct cache_node * (*cache_node_alloc_t)(struct cache *c, cache_key_t k);
-typedef int (*cache_node_flush_t)(struct cache *c, struct cache_node *cn);
+typedef bool (*cache_node_flush_t)(struct cache *c, struct cache_node *cn);
 typedef void (*cache_node_relse_t)(struct cache *c, struct cache_node *cn);
 typedef unsigned int (*cache_node_hash_t)(cache_key_t, unsigned int,
 					  unsigned int);
@@ -132,7 +132,7 @@ int cache_init(int flags, unsigned int size,
 void cache_destroy(struct cache *cache);
 void cache_walk(struct cache *cache, cache_walk_t fn, void *data);
 void cache_purge(struct cache *);
-void cache_flush(struct cache *);
+bool cache_flush(struct cache *cache);
 
 int cache_node_get(struct cache *, cache_key_t, struct cache_node **);
 void cache_node_put(struct cache *, struct cache_node *);
diff --git a/lib/support/cache.c b/lib/support/cache.c
index 49568ffa6de2e4..fa07b4ad8222d2 100644
--- a/lib/support/cache.c
+++ b/lib/support/cache.c
@@ -631,18 +631,19 @@ cache_purge(
 }
 
 /*
- * Flush all nodes in the cache to disk.
+ * Flush all nodes in the cache to disk.  Returns true if the flush succeeded.
  */
-void
+bool
 cache_flush(
 	struct cache		*cache)
 {
 	struct cache_hash	*hash;
 	struct cache_node	*node;
 	int			i;
+	bool			still_dirty = false;
 
 	if (!cache->flush)
-		return;
+		return true;
 
 	for (i = 0; i < cache->c_hashsize; i++) {
 		hash = &cache->c_hash[i];
@@ -650,11 +651,13 @@ cache_flush(
 		pthread_mutex_lock(&hash->ch_mutex);
 		list_for_each_entry(node, &hash->ch_list, cn_hash) {
 			pthread_mutex_lock(&node->cn_mutex);
-			cache->flush(cache, node);
+			still_dirty |= cache->flush(cache, node);
 			pthread_mutex_unlock(&node->cn_mutex);
 		}
 		pthread_mutex_unlock(&hash->ch_mutex);
 	}
+
+	return !still_dirty;
 }
 
 #define	HASH_REPORT	(3 * HASH_CACHE_RATIO)