From: NeilBrown <neilb@suse.de>
Date: Tue, 29 Jun 2010 11:24:27 +0000 (+1000)
Subject: Rearrange code in lafs_cluster_allocate.
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=0abf58cf3fc67f660e82e13543d8efa84466d8ac;p=LaFS.git

Rearrange code in lafs_cluster_allocate.

There are two loops in lafs_cluster_allocate that I want
to combine into one.
Need to get some stuff out of the way first.

EmptyIndex handling can move up to the other special-case
handling - just change writeback_done to iounlock_block.

Converting the iolock to writeback and getting a cluster reference
can also move up easily.

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

diff --git a/cluster.c b/cluster.c
index 0dcce8f..b0fc84c 100644
--- a/cluster.c
+++ b/cluster.c
@@ -681,6 +681,28 @@ int lafs_cluster_allocate(struct block *b, int cnum)
 		return 0;
 	}
 
+	if (test_bit(B_EmptyIndex, &b->flags)) {
+		int credits = 0;
+		if (test_and_set_bit(B_Writeback, &b->flags))
+			LAFS_BUG(1, b);
+		lafs_iounlock_block(b);
+		lafs_allocated_block(fs, b, 0);
+		/* FIXME this is common code - make a function?? */
+		if (cnum) {
+			if (test_and_clear_bit(B_Realloc, &b->flags))
+				credits++;
+			LAFS_BUG(test_bit(B_Dirty, &b->flags), b);
+		} else {
+			if (test_and_clear_bit(B_Dirty, &b->flags))
+				credits++;
+			if (test_and_clear_bit(B_Realloc, &b->flags))
+				credits++;
+		}
+		lafs_writeback_done(b);
+		lafs_space_return(fs, credits);
+		return 0;
+	}
+
 	if (!test_bit(B_Index, &b->flags) &&
 	    LAFSI(b->inode)->type == TypeInodeFile) {
 		struct inode *myi = dblk(b)->my_inode;
@@ -718,6 +740,14 @@ int lafs_cluster_allocate(struct block *b, int cnum)
 			putref(b, MKREF(leaf));
 	}
 
+	if (test_and_set_bit(B_Writeback, &b->flags))
+		LAFS_BUG(1, b);
+	lafs_iounlock_block(b);
+	/* insert into list ensuring there is enough space
+	 * in cluster head
+	 */
+	getref(b, MKREF(cluster)); /* we soon own a reference in the list */
+
 	while (!err && wc->remaining < 2) {
 		// printk("Call flush - remaining = %d\n", wc->remaining);
 		if (wc->slhead.b == NULL)
@@ -727,40 +757,14 @@ int lafs_cluster_allocate(struct block *b, int cnum)
 	}
 	if (err) {
 		/* No cleaner segments - this will have to go
-		 * out with a checkpoint
+		 * out with a checkpoint.
+		 * Block is still 'dirty' - just clear writeback flag.
 		 */
-		lafs_iounlock_block(b);
-		mutex_unlock(&wc->lock);
-		return -ENOSPC;
-	}
-
-	if (test_and_set_bit(B_Writeback, &b->flags))
-		LAFS_BUG(1, b);
-	lafs_iounlock_block(b);
-
-	if (test_bit(B_EmptyIndex, &b->flags)) {
-		int credits = 0;
-		lafs_allocated_block(fs, b, 0);
-		/* FIXME this is common code - make a function?? */
-		if (cnum) {
-			if (test_and_clear_bit(B_Realloc, &b->flags))
-				credits++;
-			LAFS_BUG(test_bit(B_Dirty, &b->flags), b);
-		} else {
-			if (test_and_clear_bit(B_Dirty, &b->flags))
-				credits++;
-			if (test_and_clear_bit(B_Realloc, &b->flags))
-				credits++;
-		}
-		lafs_space_return(fs, credits);
 		lafs_writeback_done(b);
+		putref(b, MKREF(cluster));
 		mutex_unlock(&wc->lock);
-		return 0;
+		return -ENOSPC;
 	}
-	/* insert into list ensuring there is enough space
-	 * in cluster head
-	 */
-	getref(b, MKREF(cluster)); /* we soon own a reference in the list */
 	do {
 		int avail;
 		/* see how much room is in cluster.