diff options
Diffstat (limited to 'fs/btrfs/subpage.h')
| -rw-r--r-- | fs/btrfs/subpage.h | 56 |
1 files changed, 40 insertions, 16 deletions
diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h index 0120948f37a1..7accb5c40d33 100644 --- a/fs/btrfs/subpage.h +++ b/fs/btrfs/subpage.h @@ -6,10 +6,38 @@ #include <linux/spinlock.h> /* - * 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. + * Extra info for subpapge bitmap. + * + * For subpage we pack all uptodate/error/dirty/writeback/ordered bitmaps into + * one larger bitmap. + * + * This structure records how they are organized in the bitmap: + * + * /- uptodate_offset /- error_offset /- dirty_offset + * | | | + * v v v + * |u|u|u|u|........|u|u|e|e|.......|e|e| ... |o|o| + * |<- bitmap_nr_bits ->| + * |<--------------- total_nr_bits ---------------->| */ -#define BTRFS_SUBPAGE_BITMAP_SIZE 16 +struct btrfs_subpage_info { + /* Number of bits for each bitmap */ + unsigned int bitmap_nr_bits; + + /* Total number of bits for the whole bitmap */ + unsigned int total_nr_bits; + + /* + * *_start indicates where the bitmap starts, the length is always + * @bitmap_size, which is calculated from PAGE_SIZE / sectorsize. + */ + unsigned int uptodate_offset; + unsigned int error_offset; + unsigned int dirty_offset; + unsigned int writeback_offset; + unsigned int ordered_offset; + unsigned int checked_offset; +}; /* * Structure to trace status of each sector inside a page, attached to @@ -18,10 +46,6 @@ struct btrfs_subpage { /* Common members for both data and metadata pages */ spinlock_t lock; - u16 uptodate_bitmap; - u16 error_bitmap; - u16 dirty_bitmap; - u16 writeback_bitmap; /* * Both data and metadata needs to track how many readers are for the * page. @@ -38,14 +62,11 @@ struct btrfs_subpage { * manages whether the subpage can be detached. */ atomic_t eb_refs; - /* Structures only used by data */ - struct { - atomic_t writers; - /* Tracke pending ordered extent in this sector */ - u16 ordered_bitmap; - }; + /* Structures only used by data */ + atomic_t writers; }; + unsigned long bitmaps[]; }; enum btrfs_subpage_type { @@ -53,15 +74,15 @@ enum btrfs_subpage_type { BTRFS_SUBPAGE_DATA, }; +void btrfs_init_subpage_info(struct btrfs_subpage_info *subpage_info, u32 sectorsize); 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); /* Allocate additional data where page represents more than one sector */ -int btrfs_alloc_subpage(const struct btrfs_fs_info *fs_info, - struct btrfs_subpage **ret, - enum btrfs_subpage_type type); +struct btrfs_subpage *btrfs_alloc_subpage(const struct btrfs_fs_info *fs_info, + enum btrfs_subpage_type type); void btrfs_free_subpage(struct btrfs_subpage *subpage); void btrfs_page_inc_eb_refs(const struct btrfs_fs_info *fs_info, @@ -122,11 +143,14 @@ DECLARE_BTRFS_SUBPAGE_OPS(error); DECLARE_BTRFS_SUBPAGE_OPS(dirty); DECLARE_BTRFS_SUBPAGE_OPS(writeback); DECLARE_BTRFS_SUBPAGE_OPS(ordered); +DECLARE_BTRFS_SUBPAGE_OPS(checked); bool btrfs_subpage_clear_and_test_dirty(const struct btrfs_fs_info *fs_info, struct page *page, u64 start, u32 len); void btrfs_page_assert_not_dirty(const struct btrfs_fs_info *fs_info, struct page *page); +void btrfs_page_unlock_writer(struct btrfs_fs_info *fs_info, struct page *page, + u64 start, u32 len); #endif |