[PATCH] btrfs: tests: fix free space tree test failure on 64K page system

[Qu Wenruo <wqu@suse.com>]

When trying to load btrfs with selftest compiled in, on 64K page system
the test will always fail:

  BTRFS: selftest: running free space tree tests
  BTRFS: selftest: fs/btrfs/tests/free-space-tree-tests.c:101 free space tree is invalid
  BTRFS: selftest: fs/btrfs/tests/free-space-tree-tests.c:529 test_empty_block_group [btrfs] failed with extents, sectorsize=65536, nodesize=65536, alignment=134217728

The cause is that, after commit 801dc0c9ff1f ("btrfs: replace div_u64 by
shift in free_space_bitmap_size"), we use fs_info->sectorsize_bits for
free space cache.

But in comit fc59cfa7d2ab ("btrfs: use precalculated sectorsize_bits
from fs_info"), we only initialized the fs_info for non-testing
environment, leaving the default bits to be ilog2(4K), screwing up the
selftest on 64K page system.

Fix it by also honor sectorsize_bits in selftest.

David, please fold this fix into the offending commit.

Fixes: fc59cfa7d2ab ("btrfs: use precalculated sectorsize_bits from fs_info")
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/tests/btrfs-tests.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/btrfs/tests/btrfs-tests.c b/fs/btrfs/tests/btrfs-tests.c
index 8519f7746b2e..8ca334d554af 100644
--- a/fs/btrfs/tests/btrfs-tests.c
+++ b/fs/btrfs/tests/btrfs-tests.c
@@ -134,6 +134,7 @@ struct btrfs_fs_info *btrfs_alloc_dummy_fs_info(u32 nodesize, u32 sectorsize)
 
 	fs_info->nodesize = nodesize;
 	fs_info->sectorsize = sectorsize;
+	fs_info->sectorsize_bits = ilog2(sectorsize);
 	set_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state);
 
 	test_mnt->mnt_sb->s_fs_info = fs_info;
-- 
2.29.2