1 /* SPDX-License-Identifier: GPL-2.0 */ 2 3 #ifndef BTRFS_SUBPAGE_H 4 #define BTRFS_SUBPAGE_H 5 6 #include <linux/spinlock.h> 7 #include <linux/atomic.h> 8 #include <linux/sizes.h> 9 10 struct address_space; 11 struct folio; 12 struct btrfs_fs_info; 13 14 /* 15 * Extra info for subpapge bitmap. 16 * 17 * For subpage we pack all uptodate/dirty/writeback/ordered bitmaps into 18 * one larger bitmap. 19 * 20 * This structure records how they are organized in the bitmap: 21 * 22 * /- uptodate /- dirty /- ordered 23 * | | | 24 * v v v 25 * |u|u|u|u|........|u|u|d|d|.......|d|d|o|o|.......|o|o| 26 * |< sectors_per_page >| 27 * 28 * Unlike regular macro-like enums, here we do not go upper-case names, as 29 * these names will be utilized in various macros to define function names. 30 */ 31 enum { 32 btrfs_bitmap_nr_uptodate = 0, 33 btrfs_bitmap_nr_dirty, 34 btrfs_bitmap_nr_writeback, 35 btrfs_bitmap_nr_ordered, 36 btrfs_bitmap_nr_checked, 37 btrfs_bitmap_nr_locked, 38 btrfs_bitmap_nr_max 39 }; 40 41 /* 42 * Structure to trace status of each sector inside a page, attached to 43 * page::private for both data and metadata inodes. 44 */ 45 struct btrfs_subpage { 46 /* Common members for both data and metadata pages */ 47 spinlock_t lock; 48 union { 49 /* 50 * Structures only used by metadata 51 * 52 * @eb_refs should only be operated under private_lock, as it 53 * manages whether the subpage can be detached. 54 */ 55 atomic_t eb_refs; 56 57 /* 58 * Structures only used by data, 59 * 60 * How many sectors inside the page is locked. 61 */ 62 atomic_t nr_locked; 63 }; 64 unsigned long bitmaps[]; 65 }; 66 67 enum btrfs_subpage_type { 68 BTRFS_SUBPAGE_METADATA, 69 BTRFS_SUBPAGE_DATA, 70 }; 71 72 #if PAGE_SIZE > SZ_4K 73 bool btrfs_is_subpage(const struct btrfs_fs_info *fs_info, struct address_space *mapping); 74 #else 75 static inline bool btrfs_is_subpage(const struct btrfs_fs_info *fs_info, 76 struct address_space *mapping) 77 { 78 return false; 79 } 80 #endif 81 82 int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info, 83 struct folio *folio, enum btrfs_subpage_type type); 84 void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info, struct folio *folio); 85 86 /* Allocate additional data where page represents more than one sector */ 87 struct btrfs_subpage *btrfs_alloc_subpage(const struct btrfs_fs_info *fs_info, 88 enum btrfs_subpage_type type); 89 void btrfs_free_subpage(struct btrfs_subpage *subpage); 90 91 void btrfs_folio_inc_eb_refs(const struct btrfs_fs_info *fs_info, struct folio *folio); 92 void btrfs_folio_dec_eb_refs(const struct btrfs_fs_info *fs_info, struct folio *folio); 93 94 void btrfs_folio_end_lock(const struct btrfs_fs_info *fs_info, 95 struct folio *folio, u64 start, u32 len); 96 void btrfs_folio_set_lock(const struct btrfs_fs_info *fs_info, 97 struct folio *folio, u64 start, u32 len); 98 void btrfs_folio_end_lock_bitmap(const struct btrfs_fs_info *fs_info, 99 struct folio *folio, unsigned long bitmap); 100 /* 101 * Template for subpage related operations. 102 * 103 * btrfs_subpage_*() are for call sites where the folio has subpage attached and 104 * the range is ensured to be inside the folio's single page. 105 * 106 * btrfs_folio_*() are for call sites where the page can either be subpage 107 * specific or regular folios. The function will handle both cases. 108 * But the range still needs to be inside one single page. 109 * 110 * btrfs_folio_clamp_*() are similar to btrfs_folio_*(), except the range doesn't 111 * need to be inside the page. Those functions will truncate the range 112 * automatically. 113 */ 114 #define DECLARE_BTRFS_SUBPAGE_OPS(name) \ 115 void btrfs_subpage_set_##name(const struct btrfs_fs_info *fs_info, \ 116 struct folio *folio, u64 start, u32 len); \ 117 void btrfs_subpage_clear_##name(const struct btrfs_fs_info *fs_info, \ 118 struct folio *folio, u64 start, u32 len); \ 119 bool btrfs_subpage_test_##name(const struct btrfs_fs_info *fs_info, \ 120 struct folio *folio, u64 start, u32 len); \ 121 void btrfs_folio_set_##name(const struct btrfs_fs_info *fs_info, \ 122 struct folio *folio, u64 start, u32 len); \ 123 void btrfs_folio_clear_##name(const struct btrfs_fs_info *fs_info, \ 124 struct folio *folio, u64 start, u32 len); \ 125 bool btrfs_folio_test_##name(const struct btrfs_fs_info *fs_info, \ 126 struct folio *folio, u64 start, u32 len); \ 127 void btrfs_folio_clamp_set_##name(const struct btrfs_fs_info *fs_info, \ 128 struct folio *folio, u64 start, u32 len); \ 129 void btrfs_folio_clamp_clear_##name(const struct btrfs_fs_info *fs_info, \ 130 struct folio *folio, u64 start, u32 len); \ 131 bool btrfs_folio_clamp_test_##name(const struct btrfs_fs_info *fs_info, \ 132 struct folio *folio, u64 start, u32 len); 133 134 DECLARE_BTRFS_SUBPAGE_OPS(uptodate); 135 DECLARE_BTRFS_SUBPAGE_OPS(dirty); 136 DECLARE_BTRFS_SUBPAGE_OPS(writeback); 137 DECLARE_BTRFS_SUBPAGE_OPS(ordered); 138 DECLARE_BTRFS_SUBPAGE_OPS(checked); 139 140 bool btrfs_subpage_clear_and_test_dirty(const struct btrfs_fs_info *fs_info, 141 struct folio *folio, u64 start, u32 len); 142 143 void btrfs_folio_assert_not_dirty(const struct btrfs_fs_info *fs_info, 144 struct folio *folio, u64 start, u32 len); 145 void btrfs_get_subpage_dirty_bitmap(struct btrfs_fs_info *fs_info, 146 struct folio *folio, 147 unsigned long *ret_bitmap); 148 void __cold btrfs_subpage_dump_bitmap(const struct btrfs_fs_info *fs_info, 149 struct folio *folio, u64 start, u32 len); 150 151 #endif 152