From: NeilBrown <neilb@suse.de>
Date: Fri, 25 Jun 2010 06:34:50 +0000 (+1000)
Subject: Make cluster_flush conditional on there being something to write.
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=d7fb35f4fe4112aedac2287741ca07e40c86b712;p=LaFS.git

Make cluster_flush conditional on there being something to write.

Avoid inadvertent empty clusters by only writing a cluster if
there is clearly something to write.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/cluster.c b/cluster.c
index ea45fca..377d536 100644
--- a/cluster.c
+++ b/cluster.c
@@ -1317,7 +1317,10 @@ void lafs_cluster_flush(struct fs *fs, int cnum)
 {
 	struct wc *wc = &fs->wc[cnum];
 	mutex_lock(&wc->lock);
-	cluster_flush(fs, cnum);
+	if (!list_empty(&wc->clhead)
+	    || (fs->checkpointing & CH_CheckpointEnd)
+	    || wc->chead_size > sizeof(struct cluster_head))
+		cluster_flush(fs, cnum);
 	mutex_unlock(&wc->lock);
 }
 
diff --git a/file.c b/file.c
index 2c8c58b..2c178be 100644
--- a/file.c
+++ b/file.c
@@ -314,8 +314,7 @@ static void lafs_sync_page(struct page *page)
 		putdref(b);
 	}
 #else
-	if (!lafs_cluster_empty(fs, 0))
-		lafs_cluster_flush(fs, 0);
+	lafs_cluster_flush(fs, 0);
 #endif
 }