Commit 0044ae11 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: make free space cache size consistent across different PAGE_SIZE 



Currently free space cache inode size is determined by two factors:

- block group size
- PAGE_SIZE

This means, for the same sized block groups, with different PAGE_SIZE,
it will result in different inode sizes.

This will not be a good thing for subpage support, so change the
requirement for PAGE_SIZE to sectorsize.

Now for the same 4K sectorsize btrfs, it should result the same inode
size no matter what the PAGE_SIZE is.

Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 8df507cb

fs/btrfs/block-group.c

+9 −9
Original line number Diff line number Diff line
@@ -2505,7 +2505,7 @@ static int cache_save_setup(struct btrfs_block_group *block_group, 
	struct extent_changeset *data_reserved = NULL;

	u64 alloc_hint = 0;

	int dcs = BTRFS_DC_ERROR;

	u64 num_pages = 0;

	u64 cache_size = 0;

	int retries = 0;

	int ret = 0;
@@ -2617,20 +2617,20 @@ static int cache_save_setup(struct btrfs_block_group *block_group, 
	 * taking up quite a bit since it's not folded into the other space

	 * cache.

	 */

	num_pages = div_u64(block_group->length, SZ_256M);

	if (!num_pages)

		num_pages = 1;

	cache_size = div_u64(block_group->length, SZ_256M);

	if (!cache_size)

		cache_size = 1;



	num_pages *= 16;

	num_pages *= PAGE_SIZE;

	cache_size *= 16;

	cache_size *= fs_info->sectorsize;



	ret = btrfs_check_data_free_space(BTRFS_I(inode), &data_reserved, 0,

					  num_pages);

					  cache_size);

	if (ret)

		goto out_put;



	ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,

					      num_pages, num_pages,

	ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, cache_size,

					      cache_size, cache_size,

					      &alloc_hint);

	/*

	 * Our cache requires contiguous chunks so that we don't modify a bunch