From: NeilBrown <neilb@suse.de>
Date: Tue, 25 Aug 2009 07:09:54 +0000 (+1000)
Subject: IO: support loading of an index block from addr 0.
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=79ad835cdfdb202f9c05059a635b2d92f5351dc5;p=LaFS.git

IO: support loading of an index block from addr 0.

This can happen when adding blocks to a prevously truncated
file, or even when continuing with a slow truncate.

phys==0 just means the index block is empty, so honour that.
---

diff --git a/io.c b/io.c
index dcf106a..994c2ab 100644
--- a/io.c
+++ b/io.c
@@ -406,11 +406,10 @@ lafs_load_block(struct block *b)
 	if (test_bit(B_Index, &b->flags)) {
 		struct indexblock *ib = iblk(b);
 		if (b->physaddr == 0) {
-			LAFS_BUG(1, b);
-			/* I think this is really an error FIXME */
-			memset(ib->data, 0, b->inode->i_sb->s_blocksize);
+			lafs_clear_index(ib);
+			set_bit(B_Valid, &ib->b.flags);
 			lafs_iounlock_block(b);
-			return -EIO;
+			return 0;
 		}
 		page = virt_to_page(ib->data);
 		offset = offset_in_page(ib->data);