From cac06d843f259ebc4d03e4bc8af7304c17f76ee5 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Tue, 26 Jan 2021 16:33:47 +0800 Subject: btrfs: introduce the skeleton of btrfs_subpage structure For sectorsize < page size support, we need a structure to record extra status info for each sector of a page. Introduce the skeleton structure, all subpage related code would go to subpage.[ch]. Reviewed-by: Josef Bacik Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/subpage.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 fs/btrfs/subpage.h (limited to 'fs/btrfs/subpage.h') diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h new file mode 100644 index 000000000000..676280bc7562 --- /dev/null +++ b/fs/btrfs/subpage.h @@ -0,0 +1,33 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef BTRFS_SUBPAGE_H +#define BTRFS_SUBPAGE_H + +#include + +/* + * Maximum page size we support is 64K, minimum sector size is 4K, u16 bitmap + * is sufficient. Regular bitmap_* is not used due to size reasons. + */ +#define BTRFS_SUBPAGE_BITMAP_SIZE 16 + +/* + * Structure to trace status of each sector inside a page, attached to + * page::private for both data and metadata inodes. + */ +struct btrfs_subpage { + /* Common members for both data and metadata pages */ + spinlock_t lock; +}; + +enum btrfs_subpage_type { + BTRFS_SUBPAGE_METADATA, + BTRFS_SUBPAGE_DATA, +}; + +int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info, + struct page *page, enum btrfs_subpage_type type); +void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info, + struct page *page); + +#endif -- cgit v1.2.3