From: NeilBrown <neilb@suse.de>
Date: Tue, 22 Jun 2010 05:36:37 +0000 (+1000)
Subject: Allow empty index blocks to be loaded.
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=8960cf7916e59fe62ceaabf236e5ad1ea06c6759;p=LaFS.git

Allow empty index blocks to be loaded.

If physaddr is 0, then just create a clean index block.

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

diff --git a/io.c b/io.c
index d15bec8..b1615a4 100644
--- a/io.c
+++ b/io.c
@@ -409,7 +409,19 @@ lafs_load_block(struct block *b)
 	LAFS_BUG(test_bit(B_InoIdx, &b->flags), b);
 	if (test_bit(B_Index, &b->flags)) {
 		struct indexblock *ib = iblk(b);
-		LAFS_BUG(b->physaddr == 0, b);
+
+		if (b->physaddr == 0) {
+			/* An empty index block.  One doesn't
+			 * see many of these as it means we trimmed
+			 * out some blocks, but not all following
+			 * block, and block in the hole is being
+			 * looked for.  Just Create a valid clear
+			 * index block.
+			 */
+			lafs_clear_index(ib);
+			lafs_iounlock_block(b);
+			return 0;
+		}
 
 		page = virt_to_page(ib->data);
 		offset = offset_in_page(ib->data);