From: Chris Mason <chris.mason@oracle.com>
Date: Thu, 24 Sep 2009 00:23:16 +0000 (-0400)
Subject: Btrfs: Fix test_range_bit for whole file extents
X-Git-Tag: v2.6.32-rc1~57^2^2~5
X-Git-Url: http://bbs.cooldavid.org/git/?a=commitdiff_plain;h=46562cec98368623bcd18d7fd30f20c04afd5978;p=net-next-2.6.git

Btrfs: Fix test_range_bit for whole file extents

If test_range_bit finds an extent that goes all the way to (u64)-1, it
can incorrectly wrap the u64 instead of treaing it like the end of
the address space.

This just adds a check for the highest possible offset so we don't wrap.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
---

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index b9506548853..dcce98d0ec4 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1564,6 +1564,10 @@ int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
 			bitset = 0;
 			break;
 		}
+
+		if (state->end == (u64)-1)
+			break;
+
 		start = state->end + 1;
 		if (start > end)
 			break;