[PATCH] btrfs-progs: properly exclude leaves for lowmem

[Josef Bacik <josef@toxicpanda.com>]

The lowmem mode excludes all referenced blocks from the allocator in
order to avoid accidentally overwriting blocks while fixing the file
system.  However for leaves it wouldn't exclude anything, it would just
pin them down, which gets cleaned up on transaction commit.  We're safe
for the first modification, but subsequent modifications could blow up
in our face.  Fix this by properly excluding leaves as well as all of
the nodes.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 check/mode-common.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/check/mode-common.c b/check/mode-common.c
index a6489191..ef77b060 100644
--- a/check/mode-common.c
+++ b/check/mode-common.c
@@ -667,8 +667,12 @@ static int traverse_tree_blocks(struct extent_buffer *eb, int tree_root, int pin
 
 			/* If we aren't the tree root don't read the block */
 			if (level == 1 && !tree_root) {
-				btrfs_pin_extent(gfs_info, bytenr,
-						 gfs_info->nodesize);
+				if (pin)
+					btrfs_pin_extent(gfs_info, bytenr,
+							 gfs_info->nodesize);
+				else
+					set_extent_dirty(tree, bytenr,
+							 gfs_info->nodesize);
 				continue;
 			}
 
-- 
2.26.2