From: NeilBrown <neilb@suse.de>
Date: Sat, 18 Sep 2010 13:00:48 +0000 (+1000)
Subject: Introduce DelayYouth
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=b2a029bea69d62257dce059da9cd74e43a814a88;p=LaFS.git

Introduce DelayYouth

When writing out the accounting blocks we need to not update the youth
block if we happen to start a new segment.
We already do that at unmount time, so generalise it with a new flag.

Signed-Off-By: NeilBrown <neilb@suse.de>
---

diff --git a/checkpoint.c b/checkpoint.c
index 4701938..c031506 100644
--- a/checkpoint.c
+++ b/checkpoint.c
@@ -488,6 +488,9 @@ static void flush_accounting(struct fs *fs)
 
 static void finish_checkpoint(struct fs *fs, int youth)
 {
+	/* Don't want to change the youth block while writing them out */
+	set_bit(DelayYouth, &fs->fsstate);
+
 	flush_accounting(fs);
 
 	/* if we are creating a snapshot, special handling is needed */
@@ -502,6 +505,8 @@ static void finish_checkpoint(struct fs *fs, int youth)
 	dprintk("FinalFlush %d\n", fs->seq);
 	lafs_cluster_flush(fs, 0);
 
+	clear_bit(DelayYouth, &fs->fsstate);
+
 	if (!test_bit(FinalCheckpoint, &fs->fsstate))
 		lafs_seg_apply_all(fs);
 	lafs_clean_free(fs);
diff --git a/roll.c b/roll.c
index c75b1b4..e9a20fa 100644
--- a/roll.c
+++ b/roll.c
@@ -484,6 +484,7 @@ static int roll_forward(struct fs *fs)
 	fs->phase = 1;
 	fs->qphase = 0;
 	fs->checkpointing = CH_Checkpoint;
+	clear_bit(DelayYouth, &fs->fsstate);
 
 	first = fs->checkpointcluster;
 	err = roll_locate(fs, first, &next, &last, &seq, &max);
@@ -522,6 +523,7 @@ static int roll_forward(struct fs *fs)
 			if (fs->qphase == fs->phase &&
 			    fs->checkpointing) {
 				fs->checkpointing = 0;
+				clear_bit(DelayYouth, &fs->fsstate);
 				lafs_seg_apply_all(fs);
 			}
 		}
diff --git a/segments.c b/segments.c
index 847c144..12a6453 100644
--- a/segments.c
+++ b/segments.c
@@ -1089,7 +1089,7 @@ again:
 	 * FIXME there should be a more general way to delay
 	 * updates to the Youth block.
 	 */
-	if (!test_bit(FinalCheckpoint, &fs->fsstate) &&
+	if (!test_bit(DelayYouth, &fs->fsstate) &&
 	    !(ssum &&
 	      ssum->devnum == ss->dev &&
 	      ssum->segnum == ss->segment)) {
@@ -1116,7 +1116,7 @@ again:
 	if (fs->youth_next < 0x8000)
 		fs->youth_next = 0x8000;
 
-	if (ssum && test_bit(FinalCheckpoint, &fs->fsstate)) {
+	if (ssum && test_bit(DelayYouth, &fs->fsstate)) {
 		ss_put(ssum, fs);
 		ssum = NULL;
 	}
diff --git a/state.h b/state.h
index 0bc3cba..78f3deb 100644
--- a/state.h
+++ b/state.h
@@ -122,6 +122,9 @@ struct fs {
 #define CheckpointOpen 11 /* Some data has been written since the last checkpoint,
 			   * so 'next_checkpoint' is a valid timestamp
 			   */
+#define DelayYouth 12  /* While set, don't update any youth blocks.  The update will
+			* happen either during seg_apply_all or in roll-forward
+			*/
 
 	unsigned long next_checkpoint; /* Valid when CheckpointOpen is set, holds
 					* jiffie time by when we need to do a checkpoint