From: NeilBrown <neilb@suse.de>
Date: Thu, 1 Jul 2010 07:06:02 +0000 (+1000)
Subject: cluster_reset
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=bd67d7f29af28095ffd66923793deefe5a6d4ecd;p=LaFS.git

cluster_reset

split some common code into cluster_reset which should be
called after a flushing a cluster or after setting up a
new segment.

This wasn't really happening at all in one case.

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

diff --git a/cluster.c b/cluster.c
index e3dbc64..01bef68 100644
--- a/cluster.c
+++ b/cluster.c
@@ -371,6 +371,26 @@ static u64 seg_addr(struct fs *fs, struct segpos *seg)
 	return addr;
 }
 
+static void cluster_reset(struct fs *fs, struct wc *wc)
+{
+	int blocksize = fs->prime_sb->s_blocksize;
+	if (wc->seg.dev < 0) {
+		wc->remaining = 0;
+		wc->chead = NULL;
+		wc->chead_size = 0;
+		return;
+	}
+	wc->remaining = seg_remainder(fs, &wc->seg);
+	wc->chead_blocks = 1;
+	wc->remaining--;
+	wc->cluster_space = blocksize - sizeof(struct cluster_head);
+	wc->chead_size = sizeof(struct cluster_head);
+
+	wc->pending_next = (wc->pending_next+1) % 4;
+	wc->chead = page_address(wc->page[wc->pending_next]);
+	
+}
+
 static int new_segment(struct fs *fs, int cnum)
 {
 	/* new_segment can fail if cnum > 0 and there is no
@@ -393,18 +413,16 @@ static int new_segment(struct fs *fs, int cnum)
 		lafs_seg_deref(fs, p + 1, 0);
 		wc->seg.dev = -1;
 	}
-	wc->remaining = 0;
 
 	if (cnum &&
 	    fs->clean_reserved < fs->max_segment)
 			return -ENOSPC;
 	/* This gets a reference on the 'segsum' */
 	lafs_free_get(fs, &dev, &seg, 0);
-	wc->seg.dev = dev;
-	wc->seg.num = seg;
 	seg_setpos(fs, &wc->seg, segtovirt(fs, dev, seg));
+	BUG_ON(wc->seg.dev != dev);
+	BUG_ON(wc->seg.num != seg);
 
-	wc->remaining = seg_remainder(fs, &wc->seg);
 	return 0;
 }
 
@@ -793,6 +811,7 @@ int lafs_cluster_allocate(struct block *b, int cnum)
 				mutex_unlock(&wc->lock);
 				return -ENOSPC;
 			}
+			cluster_reset(fs, wc);
 		}
 	}
 
@@ -1340,13 +1359,7 @@ static void cluster_flush(struct fs *fs, int cnum)
 	dprintk("D %d\n", wake);
 
 	/* now re-initialise the cluster information */
-	wc->chead_blocks = 1;
-	wc->remaining--;
-	wc->cluster_space = sb->s_blocksize - sizeof(struct cluster_head);
-	wc->chead_size = sizeof(struct cluster_head);
-
-	wc->pending_next = (wc->pending_next+1) % 4;
-	wc->chead = page_address(wc->page[wc->pending_next]);
+	cluster_reset(fs, wc);
 
 	wait_event(wc->pending_wait,
 		   atomic_read(&wc->pending_cnt[wc->pending_next]) == 0);
@@ -1492,7 +1505,6 @@ bio_end_io_t *lafs_cluster_endio_choose(int which, int header)
 
 int lafs_cluster_init(struct fs *fs, int cnum, u64 addr, u64 prev, u64 seq)
 {
-	int blocksize = fs->prime_sb->s_blocksize;
 	struct wc *wc = &fs->wc[cnum];
 	int i;
 
@@ -1511,22 +1523,14 @@ int lafs_cluster_init(struct fs *fs, int cnum, u64 addr, u64 prev, u64 seq)
 		}
 		return -ENOMEM;
 	}
-	wc->pending_next = 0;
-	wc->chead = page_address(wc->page[wc->pending_next]);
-
-	wc->chead_blocks = 1;
-	wc->cluster_space = blocksize - sizeof(struct cluster_head);
-	wc->chead_size = sizeof(struct cluster_head);
-
+	wc->pending_next = -1;
 	wc->cluster_seq = seq;
 	wc->prev_addr = prev;
-	seg_setpos(fs, &wc->seg, addr);
-	if (cnum)
-		wc->remaining = 0;
-	else
-		wc->remaining = seg_remainder(fs, &wc->seg) - 1;/*1 for header*/
-	if (prev && cnum == 0) {
-		/* if prev == 0 this is a brand new segment for cleaning */
+
+	if (addr) {
+		seg_setpos(fs, &wc->seg, addr);
+		cluster_reset(fs, wc);
+		BUG_ON(cnum);
 		spin_lock(&fs->lock);
 		fs->free_blocks += wc->remaining+1;
 		spin_unlock(&fs->lock);