btrfs-progs: don't write memory after sb to disk

struct btrfs_super is about 3.5k but a few writing paths were writing it
out as the full 4k BTRFS_SUPER_INFO_SIZE, leaking a few hundred bytes
after the super_block onto disk.  In practice this meant the memory
after super_copy in struct btrfs_fs_info and whatever came after it in
the heap.

Signed-off-by: Zach Brown <zab@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/volumes.c b/volumes.c
index 9c527197..65986e15 100644
--- a/volumes.c
+++ b/volumes.c
@@ -1502,7 +1502,7 @@ int btrfs_read_sys_array(struct btrfs_root *root)
 	if (!sb)
 		return -ENOMEM;
 	btrfs_set_buffer_uptodate(sb);
-	write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
+	write_extent_buffer(sb, super_copy, 0, sizeof(*super_copy));
 	array_size = btrfs_super_sys_array_size(super_copy);
 
 	/*