From: NeilBrown <neilb@suse.de>
Date: Thu, 1 Jul 2010 06:58:54 +0000 (+1000)
Subject: Fix lafs_cluster_allocate to full cluster.
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=abb2bbbde356f784c745632cbb41d51acfcaf5bd;p=LaFS.git

Fix lafs_cluster_allocate to full cluster.

When we unified the two loops in lafs_cluster_allocate,
we broke handling for a nearly-full cluster.  We need to
require wc->remaining is at least 1 before we even
consider a cluster_insert.

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

diff --git a/cluster.c b/cluster.c
index 330738a..e3dbc64 100644
--- a/cluster.c
+++ b/cluster.c
@@ -762,7 +762,7 @@ int lafs_cluster_allocate(struct block *b, int cnum)
 		 */
 		if (wc->cluster_space >= (sizeof(struct group_head) +
 					  sizeof(struct descriptor)) ||
-		    (wc->remaining > 1 &&
+		    (wc->remaining > 2 &&
 		     wc->chead_blocks < MAX_CHEAD_BLOCKS &&
 		     (wc->chead_blocks+1) * sb->s_blocksize <= PAGE_SIZE)
 			)
@@ -771,7 +771,10 @@ int lafs_cluster_allocate(struct block *b, int cnum)
 			avail = 1;
 		else
 			avail = 0;
-		used = cluster_insert(&wc->slhead, &wc->clhead, b, avail);
+		if (wc->remaining < 1)
+			used = -1;
+		else
+			used = cluster_insert(&wc->slhead, &wc->clhead, b, avail);
 
 		if (used >= 0)
 			break;
@@ -804,6 +807,7 @@ int lafs_cluster_allocate(struct block *b, int cnum)
 		wc->cluster_space += sb->s_blocksize;
 	}
 	wc->remaining--;
+	BUG_ON(wc->remaining < 0);
 	if (wc->remaining == 0)
 		cluster_flush(fs, cnum);
 	mutex_unlock(&wc->lock);