1/* SPDX-License-Identifier: GPL-2.0 */
2
3#ifndef BTRFS_EXTENT_IO_H
4#define BTRFS_EXTENT_IO_H
5
6#include <linux/rbtree.h>
7#include <linux/refcount.h>
8#include <linux/fiemap.h>
9#include <linux/btrfs_tree.h>
10#include <linux/spinlock.h>
11#include <linux/atomic.h>
12#include <linux/rwsem.h>
13#include <linux/list.h>
14#include <linux/slab.h>
15#include "compression.h"
16#include "messages.h"
17#include "ulist.h"
18#include "misc.h"
19
20struct page;
21struct file;
22struct folio;
23struct inode;
24struct fiemap_extent_info;
25struct readahead_control;
26struct address_space;
27struct writeback_control;
28struct extent_io_tree;
29struct extent_map_tree;
30struct btrfs_block_group;
31struct btrfs_fs_info;
32struct btrfs_inode;
33struct btrfs_root;
34struct btrfs_trans_handle;
35struct btrfs_tree_parent_check;
36
37enum {
38 EXTENT_BUFFER_UPTODATE,
39 EXTENT_BUFFER_DIRTY,
40 EXTENT_BUFFER_CORRUPT,
41 /* this got triggered by readahead */
42 EXTENT_BUFFER_READAHEAD,
43 EXTENT_BUFFER_TREE_REF,
44 EXTENT_BUFFER_STALE,
45 EXTENT_BUFFER_WRITEBACK,
46 /* read IO error */
47 EXTENT_BUFFER_READ_ERR,
48 EXTENT_BUFFER_UNMAPPED,
49 EXTENT_BUFFER_IN_TREE,
50 /* write IO error */
51 EXTENT_BUFFER_WRITE_ERR,
52 /* Indicate the extent buffer is written zeroed out (for zoned) */
53 EXTENT_BUFFER_ZONED_ZEROOUT,
54 /* Indicate that extent buffer pages a being read */
55 EXTENT_BUFFER_READING,
56};
57
58/* these are flags for __process_pages_contig */
59enum {
60 ENUM_BIT(PAGE_UNLOCK),
61 /* Page starts writeback, clear dirty bit and set writeback bit */
62 ENUM_BIT(PAGE_START_WRITEBACK),
63 ENUM_BIT(PAGE_END_WRITEBACK),
64 ENUM_BIT(PAGE_SET_ORDERED),
65};
66
67/*
68 * Folio private values. Every page that is controlled by the extent map has
69 * folio private set to this value.
70 */
71#define EXTENT_FOLIO_PRIVATE 1
72
73/*
74 * The extent buffer bitmap operations are done with byte granularity instead of
75 * word granularity for two reasons:
76 * 1. The bitmaps must be little-endian on disk.
77 * 2. Bitmap items are not guaranteed to be aligned to a word and therefore a
78 * single word in a bitmap may straddle two pages in the extent buffer.
79 */
80#define BIT_BYTE(nr) ((nr) / BITS_PER_BYTE)
81#define BYTE_MASK ((1 << BITS_PER_BYTE) - 1)
82#define BITMAP_FIRST_BYTE_MASK(start) \
83 ((BYTE_MASK << ((start) & (BITS_PER_BYTE - 1))) & BYTE_MASK)
84#define BITMAP_LAST_BYTE_MASK(nbits) \
85 (BYTE_MASK >> (-(nbits) & (BITS_PER_BYTE - 1)))
86
87
88int __init extent_buffer_init_cachep(void);
89void __cold extent_buffer_free_cachep(void);
90
91#define INLINE_EXTENT_BUFFER_PAGES (BTRFS_MAX_METADATA_BLOCKSIZE / PAGE_SIZE)
92struct extent_buffer {
93 u64 start;
94 u32 len;
95 u32 folio_size;
96 unsigned long bflags;
97 struct btrfs_fs_info *fs_info;
98
99 /*
100 * The address where the eb can be accessed without any cross-page handling.
101 * This can be NULL if not possible.
102 */
103 void *addr;
104
105 spinlock_t refs_lock;
106 atomic_t refs;
107 int read_mirror;
108 /* >= 0 if eb belongs to a log tree, -1 otherwise */
109 s8 log_index;
110 u8 folio_shift;
111 struct rcu_head rcu_head;
112
113 struct rw_semaphore lock;
114
115 /*
116 * Pointers to all the folios of the extent buffer.
117 *
118 * For now the folio is always order 0 (aka, a single page).
119 */
120 struct folio *folios[INLINE_EXTENT_BUFFER_PAGES];
121#ifdef CONFIG_BTRFS_DEBUG
122 struct list_head leak_list;
123 pid_t lock_owner;
124#endif
125};
126
127struct btrfs_eb_write_context {
128 struct writeback_control *wbc;
129 struct extent_buffer *eb;
130 /* Block group @eb resides in. Only used for zoned mode. */
131 struct btrfs_block_group *zoned_bg;
132};
133
134static inline unsigned long offset_in_eb_folio(const struct extent_buffer *eb,
135 u64 start)
136{
137 ASSERT(eb->folio_size);
138 return start & (eb->folio_size - 1);
139}
140
141/*
142 * Get the correct offset inside the page of extent buffer.
143 *
144 * @eb: target extent buffer
145 * @start: offset inside the extent buffer
146 *
147 * Will handle both sectorsize == PAGE_SIZE and sectorsize < PAGE_SIZE cases.
148 */
149static inline size_t get_eb_offset_in_folio(const struct extent_buffer *eb,
150 unsigned long offset)
151{
152 /*
153 * 1) sectorsize == PAGE_SIZE and nodesize >= PAGE_SIZE case
154 * 1.1) One large folio covering the whole eb
155 * The eb->start is aligned to folio size, thus adding it
156 * won't cause any difference.
157 * 1.2) Several page sized folios
158 * The eb->start is aligned to folio (page) size, thus
159 * adding it won't cause any difference.
160 *
161 * 2) sectorsize < PAGE_SIZE and nodesize < PAGE_SIZE case
162 * In this case there would only be one page sized folio, and there
163 * may be several different extent buffers in the page/folio.
164 * We need to add eb->start to properly access the offset inside
165 * that eb.
166 */
167 return offset_in_folio(eb->folios[0], offset + eb->start);
168}
169
170static inline unsigned long get_eb_folio_index(const struct extent_buffer *eb,
171 unsigned long offset)
172{
173 /*
174 * 1) sectorsize == PAGE_SIZE and nodesize >= PAGE_SIZE case
175 * 1.1) One large folio covering the whole eb.
176 * the folio_shift would be large enough to always make us
177 * return 0 as index.
178 * 1.2) Several page sized folios
179 * The folio_shift would be PAGE_SHIFT, giving us the correct
180 * index.
181 *
182 * 2) sectorsize < PAGE_SIZE and nodesize < PAGE_SIZE case
183 * The folio would only be page sized, and always give us 0 as index.
184 */
185 return offset >> eb->folio_shift;
186}
187
188/*
189 * Structure to record how many bytes and which ranges are set/cleared
190 */
191struct extent_changeset {
192 /* How many bytes are set/cleared in this operation */
193 u64 bytes_changed;
194
195 /* Changed ranges */
196 struct ulist range_changed;
197};
198
199static inline void extent_changeset_init(struct extent_changeset *changeset)
200{
201 changeset->bytes_changed = 0;
202 ulist_init(ulist: &changeset->range_changed);
203}
204
205static inline struct extent_changeset *extent_changeset_alloc(void)
206{
207 struct extent_changeset *ret;
208
209 ret = kmalloc(size: sizeof(*ret), GFP_KERNEL);
210 if (!ret)
211 return NULL;
212
213 extent_changeset_init(changeset: ret);
214 return ret;
215}
216
217static inline void extent_changeset_release(struct extent_changeset *changeset)
218{
219 if (!changeset)
220 return;
221 changeset->bytes_changed = 0;
222 ulist_release(ulist: &changeset->range_changed);
223}
224
225static inline void extent_changeset_free(struct extent_changeset *changeset)
226{
227 if (!changeset)
228 return;
229 extent_changeset_release(changeset);
230 kfree(objp: changeset);
231}
232
233int try_release_extent_mapping(struct page *page, gfp_t mask);
234int try_release_extent_buffer(struct page *page);
235
236int btrfs_read_folio(struct file *file, struct folio *folio);
237void extent_write_locked_range(struct inode *inode, struct page *locked_page,
238 u64 start, u64 end, struct writeback_control *wbc,
239 bool pages_dirty);
240int extent_writepages(struct address_space *mapping,
241 struct writeback_control *wbc);
242int btree_write_cache_pages(struct address_space *mapping,
243 struct writeback_control *wbc);
244void extent_readahead(struct readahead_control *rac);
245int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
246 u64 start, u64 len);
247int set_folio_extent_mapped(struct folio *folio);
248int set_page_extent_mapped(struct page *page);
249void clear_page_extent_mapped(struct page *page);
250
251struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
252 u64 start, u64 owner_root, int level);
253struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
254 u64 start, unsigned long len);
255struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
256 u64 start);
257struct extent_buffer *btrfs_clone_extent_buffer(const struct extent_buffer *src);
258struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
259 u64 start);
260void free_extent_buffer(struct extent_buffer *eb);
261void free_extent_buffer_stale(struct extent_buffer *eb);
262#define WAIT_NONE 0
263#define WAIT_COMPLETE 1
264#define WAIT_PAGE_LOCK 2
265int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
266 struct btrfs_tree_parent_check *parent_check);
267void wait_on_extent_buffer_writeback(struct extent_buffer *eb);
268void btrfs_readahead_tree_block(struct btrfs_fs_info *fs_info,
269 u64 bytenr, u64 owner_root, u64 gen, int level);
270void btrfs_readahead_node_child(struct extent_buffer *node, int slot);
271
272static inline int num_extent_pages(const struct extent_buffer *eb)
273{
274 /*
275 * For sectorsize == PAGE_SIZE case, since nodesize is always aligned to
276 * sectorsize, it's just eb->len >> PAGE_SHIFT.
277 *
278 * For sectorsize < PAGE_SIZE case, we could have nodesize < PAGE_SIZE,
279 * thus have to ensure we get at least one page.
280 */
281 return (eb->len >> PAGE_SHIFT) ?: 1;
282}
283
284/*
285 * This can only be determined at runtime by checking eb::folios[0].
286 *
287 * As we can have either one large folio covering the whole eb
288 * (either nodesize <= PAGE_SIZE, or high order folio), or multiple
289 * single-paged folios.
290 */
291static inline int num_extent_folios(const struct extent_buffer *eb)
292{
293 if (folio_order(folio: eb->folios[0]))
294 return 1;
295 return num_extent_pages(eb);
296}
297
298static inline int extent_buffer_uptodate(const struct extent_buffer *eb)
299{
300 return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
301}
302
303int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
304 unsigned long start, unsigned long len);
305void read_extent_buffer(const struct extent_buffer *eb, void *dst,
306 unsigned long start,
307 unsigned long len);
308int read_extent_buffer_to_user_nofault(const struct extent_buffer *eb,
309 void __user *dst, unsigned long start,
310 unsigned long len);
311void write_extent_buffer(const struct extent_buffer *eb, const void *src,
312 unsigned long start, unsigned long len);
313
314static inline void write_extent_buffer_chunk_tree_uuid(
315 const struct extent_buffer *eb, const void *chunk_tree_uuid)
316{
317 write_extent_buffer(eb, src: chunk_tree_uuid,
318 offsetof(struct btrfs_header, chunk_tree_uuid),
319 BTRFS_FSID_SIZE);
320}
321
322static inline void write_extent_buffer_fsid(const struct extent_buffer *eb,
323 const void *fsid)
324{
325 write_extent_buffer(eb, src: fsid, offsetof(struct btrfs_header, fsid),
326 BTRFS_FSID_SIZE);
327}
328
329void copy_extent_buffer_full(const struct extent_buffer *dst,
330 const struct extent_buffer *src);
331void copy_extent_buffer(const struct extent_buffer *dst,
332 const struct extent_buffer *src,
333 unsigned long dst_offset, unsigned long src_offset,
334 unsigned long len);
335void memcpy_extent_buffer(const struct extent_buffer *dst,
336 unsigned long dst_offset, unsigned long src_offset,
337 unsigned long len);
338void memmove_extent_buffer(const struct extent_buffer *dst,
339 unsigned long dst_offset, unsigned long src_offset,
340 unsigned long len);
341void memzero_extent_buffer(const struct extent_buffer *eb, unsigned long start,
342 unsigned long len);
343int extent_buffer_test_bit(const struct extent_buffer *eb, unsigned long start,
344 unsigned long pos);
345void extent_buffer_bitmap_set(const struct extent_buffer *eb, unsigned long start,
346 unsigned long pos, unsigned long len);
347void extent_buffer_bitmap_clear(const struct extent_buffer *eb,
348 unsigned long start, unsigned long pos,
349 unsigned long len);
350void set_extent_buffer_dirty(struct extent_buffer *eb);
351void set_extent_buffer_uptodate(struct extent_buffer *eb);
352void clear_extent_buffer_uptodate(struct extent_buffer *eb);
353void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end);
354void extent_clear_unlock_delalloc(struct btrfs_inode *inode, u64 start, u64 end,
355 struct page *locked_page,
356 u32 bits_to_clear, unsigned long page_ops);
357int extent_invalidate_folio(struct extent_io_tree *tree,
358 struct folio *folio, size_t offset);
359void btrfs_clear_buffer_dirty(struct btrfs_trans_handle *trans,
360 struct extent_buffer *buf);
361
362int btrfs_alloc_page_array(unsigned int nr_pages, struct page **page_array,
363 gfp_t extra_gfp);
364
365#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
366bool find_lock_delalloc_range(struct inode *inode,
367 struct page *locked_page, u64 *start,
368 u64 *end);
369#endif
370struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
371 u64 start);
372
373#ifdef CONFIG_BTRFS_DEBUG
374void btrfs_extent_buffer_leak_debug_check(struct btrfs_fs_info *fs_info);
375#else
376#define btrfs_extent_buffer_leak_debug_check(fs_info) do {} while (0)
377#endif
378
379#endif
380

source code of linux/fs/btrfs/extent_io.h