FS-Cache: Limit the number of I/O error reports for a cache

Limit the number of I/O error reports for a cache to 1 to prevent massive
amounts of noise.  After the first I/O error the cache is taken off line
automatically, so must be restarted to resume caching.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

fs/fscache/cache.c

@@ -314,10 +314,10 @@ EXPORT_SYMBOL(fscache_add_cache);
  */
 void fscache_io_error(struct fscache_cache *cache)
 {
-	set_bit(FSCACHE_IOERROR, &cache->flags);
-
-	printk(KERN_ERR "FS-Cache: Cache %s stopped due to I/O error\n",
-	       cache->ops->name);
+	if (!test_and_set_bit(FSCACHE_IOERROR, &cache->flags))
+		printk(KERN_ERR "FS-Cache:"
+		       " Cache '%s' stopped due to I/O error\n",
+		       cache->ops->name);
 }
 EXPORT_SYMBOL(fscache_io_error);