pnfs: clean up filelayout_alloc_commit_info

Remove unneeded else statement and clean up how commit info
dataserver buckets are replaced.
Suggested-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/nfs4filelayout.c

@@ -850,11 +850,15 @@ filelayout_alloc_commit_info(struct pnfs_layout_segment *lseg,
 {
 	struct nfs4_filelayout_segment *fl = FILELAYOUT_LSEG(lseg);
 	struct pnfs_commit_bucket *buckets;
-	int size;
+	int size, i;
 
 	if (fl->commit_through_mds)
 		return 0;
-	if (cinfo->ds->nbuckets != 0) {
+
+	size = (fl->stripe_type == STRIPE_SPARSE) ?
+		fl->dsaddr->ds_num : fl->dsaddr->stripe_count;
+
+	if (cinfo->ds->nbuckets >= size) {
 		/* This assumes there is only one IOMODE_RW lseg.  What
 		 * we really want to do is have a layout_hdr level
 		 * dictionary of <multipath_list4, fh> keys, each
@@ -864,30 +868,32 @@ filelayout_alloc_commit_info(struct pnfs_layout_segment *lseg,
 		return 0;
 	}
 
-	size = (fl->stripe_type == STRIPE_SPARSE) ?
-		fl->dsaddr->ds_num : fl->dsaddr->stripe_count;
-
 	buckets = kcalloc(size, sizeof(struct pnfs_commit_bucket),
 			  gfp_flags);
 	if (!buckets)
 		return -ENOMEM;
-	else {
-		int i;
-
-		spin_lock(cinfo->lock);
-		if (cinfo->ds->nbuckets != 0)
-			kfree(buckets);
-		else {
-			cinfo->ds->buckets = buckets;
-			cinfo->ds->nbuckets = size;
 	for (i = 0; i < size; i++) {
 		INIT_LIST_HEAD(&buckets[i].written);
 		INIT_LIST_HEAD(&buckets[i].committing);
 	}
+
+	spin_lock(cinfo->lock);
+	if (cinfo->ds->nbuckets >= size)
+		goto out;
+	for (i = 0; i < cinfo->ds->nbuckets; i++) {
+		list_splice(&cinfo->ds->buckets[i].written,
+			    &buckets[i].written);
+		list_splice(&cinfo->ds->buckets[i].committing,
+			    &buckets[i].committing);
+		buckets[i].wlseg = cinfo->ds->buckets[i].wlseg;
+		buckets[i].clseg = cinfo->ds->buckets[i].clseg;
 	}
+	swap(cinfo->ds->buckets, buckets);
+	cinfo->ds->nbuckets = size;
+out:
 	spin_unlock(cinfo->lock);
+	kfree(buckets);
 	return 0;
-	}
 }
 
 static struct pnfs_layout_segment *