[PATCH 1/6] btrfs-progs: Exit gracefully if we hit ENOSPC when allocating tree block

[Qu Wenruo <wqu@suse.com>]

When running test fuzz/003, we could hit the following BUG_ON:
------
====== RUN MAYFAIL /home/adam/btrfs/btrfs-progs/btrfs check --init-csum-tree /home/adam/btrfs/btrfs-progs/tests//fuzz-tests/images/bko-155621-bad-block-group-offset.raw.restored
Unable to find block group for 0
Unable to find block group for 0
Unable to find block group for 0
extent-tree.c:2657: alloc_tree_block: BUG_ON `ret` triggered, value -28
failed (ignored, ret=134): /home/adam/btrfs/btrfs-progs/btrfs check --init-csum-tree /home/adam/btrfs/btrfs-progs/tests//fuzz-tests/images/bko-155621-bad-block-group-offset.raw.restored
mayfail: returned code 134 (SIGABRT), not ignored
test failed for case 003-multi-check-unmounted
------

Just remove that BUG_ON() and allow us to exit gracefully.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 extent-tree.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/extent-tree.c b/extent-tree.c
index b9d51b388c9a..a1f711ece7a8 100644
--- a/extent-tree.c
+++ b/extent-tree.c
@@ -2654,7 +2654,10 @@ static int alloc_tree_block(struct btrfs_trans_handle *trans,
 
 	ret = btrfs_reserve_extent(trans, root, num_bytes, empty_size,
 				   hint_byte, search_end, ins, 0);
-	BUG_ON(ret);
+	if (ret < 0) {
+		btrfs_free_delayed_extent_op(extent_op);
+		return ret;
+	}
 
 	if (key)
 		memcpy(&extent_op->key, key, sizeof(extent_op->key));
-- 
2.18.0