From: NeilBrown <neilb@suse.de>
Date: Tue, 14 Sep 2010 01:10:25 +0000 (+1000)
Subject: Make sure checkpoint happens after a timeout.
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=b299ed4d5ba239710a6894b1e175137a3d214098;p=LaFS.git

Make sure checkpoint happens after a timeout.

If anything has been written since last check point, ensure another
checkpoint happens within 30 seconds.

This is partly to ensure that index block don't remain dirty forever.

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

diff --git a/checkpoint.c b/checkpoint.c
index 32ab345..93e5082 100644
--- a/checkpoint.c
+++ b/checkpoint.c
@@ -539,9 +539,18 @@ unsigned long lafs_do_checkpoint(struct fs *fs)
 		if (fs->cleaner.active == 0 &&
 		    fs->newsegments > fs->max_newsegs)
 			set_bit(CheckpointNeeded, &fs->fsstate);
+		else if (test_bit(CheckpointOpen, &fs->fsstate)) {
+			unsigned long j = jiffies;
+			if (time_after_eq(j, fs->next_checkpoint))
+				set_bit(CheckpointNeeded, &fs->fsstate);
+			else
+				return fs->next_checkpoint - j;
+		} else
+			return MAX_SCHEDULE_TIMEOUT;
 	}
 
 	if (!test_bit(CheckpointNeeded, &fs->fsstate))
+		/* Must have done final checkpoint */
 		return MAX_SCHEDULE_TIMEOUT;
 
 	if (fs->cleaner.active || ! fs->scan.done)
diff --git a/cluster.c b/cluster.c
index e663391..1f317c1 100644
--- a/cluster.c
+++ b/cluster.c
@@ -1140,6 +1140,14 @@ static void cluster_flush(struct fs *fs, int cnum)
 	int vtype;
 	int cluster_size;
 
+	if (!test_bit(CheckpointOpen, &fs->fsstate)) {
+		/* First cluster since a checkpoint, make sure
+		 * we do another checkpoint within 30 seconds
+		 */
+		fs->next_checkpoint = jiffies + 30 * HZ;
+		set_bit(CheckpointOpen, &fs->fsstate);
+		lafs_wake_thread(fs);
+	}
 	/* set the writecluster size as this will guide layout in
 	 * some cases
 	 */
@@ -1212,9 +1220,10 @@ static void cluster_flush(struct fs *fs, int cnum)
 		if (fs->checkpointing) {
 			spin_lock(&fs->lock);
 			wc->chead->flags = cpu_to_le32(fs->checkpointing);
-			if (fs->checkpointing & CH_CheckpointEnd)
+			if (fs->checkpointing & CH_CheckpointEnd) {
 				fs->checkpointing = 0;
-			else if (fs->checkpointing & CH_CheckpointStart) {
+				clear_bit(CheckpointOpen, &fs->fsstate);
+			} else if (fs->checkpointing & CH_CheckpointStart) {
 				fs->checkpointcluster = head_addr[0];
 				fs->checkpointing &= ~CH_CheckpointStart;
 			}
diff --git a/index.c b/index.c
index 79bca85..65d36c8 100644
--- a/index.c
+++ b/index.c
@@ -97,9 +97,6 @@ static int lafs_shrinker(int nr_to_scan, /*gfp_t*/unsigned int gfp_mask)
 			list_del(&ib->b.lru);
 			lafs_iblock_free(ib);
 		}
-		/* FIXME
-		 * while (nr_to_scan) trigger some flushing
-		 */
 	}
 	return freelist.freecnt;
 }
diff --git a/state.h b/state.h
index 589a56e..57bdddf 100644
--- a/state.h
+++ b/state.h
@@ -119,6 +119,13 @@ struct fs {
 			     * should be after the next checkpoint unless that
 			     * releases lots of space
 			     */
+#define CheckpointOpen 11 /* Some data has been written since the last checkpoint,
+			   * so 'next_checkpoint' is a valid timestamp
+			   */
+
+	unsigned long next_checkpoint; /* Valid when CheckpointOpen is set, holds
+					* jiffie time by when we need to do a checkpoint
+					*/
 
 	struct work_struct done_work;	/* used for handling
 					 * refile after write completes */