[1/6] btrfs-progs: Allow btrfs_print_leaf() to be called on dummy eb whose fs_info is NULL

Commit Message

Qu Wenruo May 27, 2020, 10:28 a.m. UTC

In certain call sites, like btrfs-image, we want full extent_buffer
accessors, but don't have a btrfs_fs_info.

In that case, if an extent buffer whose fs_info is NULL, then
btrfs_print_leaf() is called on such eb, we will trigger a NULL pointer
dereference, at BTRFS_LEAF_DATA_SIZE(fs_info).

Fix this by using __BTRFS_LEAF_DATA_SIZE(), which only needs nodesize,
and nodesize can be extracted from extent_buffer::len.

This allows us to call btrfs_print_leaf() on any extent buffer, which is
super handy in gdb.

Signed-off-by: Qu Wenruo <[e-mail]>
---
 print-tree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

diff --git a/print-tree.c b/print-tree.c
index 27acadb22205..38cf8d34ac2e 100644
--- a/print-tree.c
+++ b/print-tree.c
@@ -1201,7 +1201,7 @@  void btrfs_print_leaf(struct extent_buffer *eb)
 	struct btrfs_item *item;
 	struct btrfs_disk_key disk_key;
 	char flags_str[128];
-	u32 leaf_data_size = BTRFS_LEAF_DATA_SIZE(fs_info);
+	u32 leaf_data_size = __BTRFS_LEAF_DATA_SIZE(eb->len);
 	u32 i;
 	u32 nr;
 	u64 flags;