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 "messages.h"
16#include "ulist.h"
17#include "misc.h"
18
19struct page;
20struct file;
21struct folio;
22struct inode;
23struct fiemap_extent_info;
24struct readahead_control;
25struct address_space;
26struct writeback_control;
27struct extent_io_tree;
28struct extent_map_tree;
29struct extent_state;
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_TREE_REF,
41 EXTENT_BUFFER_STALE,
42 EXTENT_BUFFER_WRITEBACK,
43 EXTENT_BUFFER_UNMAPPED,
44 /* write IO error */
45 EXTENT_BUFFER_WRITE_ERR,
46 /* Indicate the extent buffer is written zeroed out (for zoned) */
47 EXTENT_BUFFER_ZONED_ZEROOUT,
48 /* Indicate that extent buffer pages a being read */
49 EXTENT_BUFFER_READING,
50};
51
52/* these are flags for __process_pages_contig */
53enum {
54 ENUM_BIT(PAGE_UNLOCK),
55 /* Page starts writeback, clear dirty bit and set writeback bit */
56 ENUM_BIT(PAGE_START_WRITEBACK),
57 ENUM_BIT(PAGE_END_WRITEBACK),
58 ENUM_BIT(PAGE_SET_ORDERED),
59};
60
61/*
62 * Folio private values. Every page that is controlled by the extent map has
63 * folio private set to this value.
64 */
65#define EXTENT_FOLIO_PRIVATE 1
66
67/*
68 * The extent buffer bitmap operations are done with byte granularity instead of
69 * word granularity for two reasons:
70 * 1. The bitmaps must be little-endian on disk.
71 * 2. Bitmap items are not guaranteed to be aligned to a word and therefore a
72 * single word in a bitmap may straddle two pages in the extent buffer.
73 */
74#define BIT_BYTE(nr) ((nr) / BITS_PER_BYTE)
75#define BYTE_MASK ((1U << BITS_PER_BYTE) - 1)
76#define BITMAP_FIRST_BYTE_MASK(start) \
77 ((BYTE_MASK << ((start) & (BITS_PER_BYTE - 1))) & BYTE_MASK)
78#define BITMAP_LAST_BYTE_MASK(nbits) \
79 (BYTE_MASK >> (-(nbits) & (BITS_PER_BYTE - 1)))
80
81
82int __init extent_buffer_init_cachep(void);
83void __cold extent_buffer_free_cachep(void);
84
85#define INLINE_EXTENT_BUFFER_PAGES (BTRFS_MAX_METADATA_BLOCKSIZE / PAGE_SIZE)
86struct extent_buffer {
87 u64 start;
88 u32 len;
89 u32 folio_size;
90 unsigned long bflags;
91 struct btrfs_fs_info *fs_info;
92
93 /*
94 * The address where the eb can be accessed without any cross-page handling.
95 * This can be NULL if not possible.
96 */
97 void *addr;
98
99 spinlock_t refs_lock;
100 refcount_t refs;
101 int read_mirror;
102 /* >= 0 if eb belongs to a log tree, -1 otherwise */
103 s8 log_index;
104 u8 folio_shift;
105 struct rcu_head rcu_head;
106
107 struct rw_semaphore lock;
108
109 /*
110 * Pointers to all the folios of the extent buffer.
111 *
112 * For now the folio is always order 0 (aka, a single page).
113 */
114 struct folio *folios[INLINE_EXTENT_BUFFER_PAGES];
115#ifdef CONFIG_BTRFS_DEBUG
116 struct list_head leak_list;
117 pid_t lock_owner;
118#endif
119};
120
121struct btrfs_eb_write_context {
122 struct writeback_control *wbc;
123 struct extent_buffer *eb;
124 /* Block group @eb resides in. Only used for zoned mode. */
125 struct btrfs_block_group *zoned_bg;
126};
127
128static inline unsigned long offset_in_eb_folio(const struct extent_buffer *eb,
129 u64 start)
130{
131 ASSERT(eb->folio_size);
132 return start & (eb->folio_size - 1);
133}
134
135/*
136 * Get the correct offset inside the page of extent buffer.
137 *
138 * @eb: target extent buffer
139 * @start: offset inside the extent buffer
140 *
141 * Will handle both sectorsize == PAGE_SIZE and sectorsize < PAGE_SIZE cases.
142 */
143static inline size_t get_eb_offset_in_folio(const struct extent_buffer *eb,
144 unsigned long offset)
145{
146 /*
147 * 1) sectorsize == PAGE_SIZE and nodesize >= PAGE_SIZE case
148 * 1.1) One large folio covering the whole eb
149 * The eb->start is aligned to folio size, thus adding it
150 * won't cause any difference.
151 * 1.2) Several page sized folios
152 * The eb->start is aligned to folio (page) size, thus
153 * adding it won't cause any difference.
154 *
155 * 2) sectorsize < PAGE_SIZE and nodesize < PAGE_SIZE case
156 * In this case there would only be one page sized folio, and there
157 * may be several different extent buffers in the page/folio.
158 * We need to add eb->start to properly access the offset inside
159 * that eb.
160 */
161 return offset_in_folio(eb->folios[0], offset + eb->start);
162}
163
164static inline unsigned long get_eb_folio_index(const struct extent_buffer *eb,
165 unsigned long offset)
166{
167 /*
168 * 1) sectorsize == PAGE_SIZE and nodesize >= PAGE_SIZE case
169 * 1.1) One large folio covering the whole eb.
170 * the folio_shift would be large enough to always make us
171 * return 0 as index.
172 * 1.2) Several page sized folios
173 * The folio_shift would be PAGE_SHIFT, giving us the correct
174 * index.
175 *
176 * 2) sectorsize < PAGE_SIZE and nodesize < PAGE_SIZE case
177 * The folio would only be page sized, and always give us 0 as index.
178 */
179 return offset >> eb->folio_shift;
180}
181
182/*
183 * Structure to record how many bytes and which ranges are set/cleared
184 */
185struct extent_changeset {
186 /* How many bytes are set/cleared in this operation */
187 u64 bytes_changed;
188
189 /* Changed ranges */
190 struct ulist range_changed;
191};
192
193static inline void extent_changeset_init(struct extent_changeset *changeset)
194{
195 changeset->bytes_changed = 0;
196 ulist_init(ulist: &changeset->range_changed);
197}
198
199static inline struct extent_changeset *extent_changeset_alloc(void)
200{
201 struct extent_changeset *ret;
202
203 ret = kmalloc(sizeof(*ret), GFP_KERNEL);
204 if (!ret)
205 return NULL;
206
207 extent_changeset_init(changeset: ret);
208 return ret;
209}
210
211static inline void extent_changeset_prealloc(struct extent_changeset *changeset, gfp_t gfp_mask)
212{
213 ulist_prealloc(ulist: &changeset->range_changed, mask: gfp_mask);
214}
215
216static inline void extent_changeset_release(struct extent_changeset *changeset)
217{
218 if (!changeset)
219 return;
220 changeset->bytes_changed = 0;
221 ulist_release(ulist: &changeset->range_changed);
222}
223
224static inline void extent_changeset_free(struct extent_changeset *changeset)
225{
226 if (!changeset)
227 return;
228 extent_changeset_release(changeset);
229 kfree(objp: changeset);
230}
231
232bool try_release_extent_mapping(struct folio *folio, gfp_t mask);
233int try_release_extent_buffer(struct folio *folio);
234
235int btrfs_read_folio(struct file *file, struct folio *folio);
236void extent_write_locked_range(struct inode *inode, const struct folio *locked_folio,
237 u64 start, u64 end, struct writeback_control *wbc,
238 bool pages_dirty);
239int btrfs_writepages(struct address_space *mapping, struct writeback_control *wbc);
240int btree_writepages(struct address_space *mapping, struct writeback_control *wbc);
241void btrfs_btree_wait_writeback_range(struct btrfs_fs_info *fs_info, u64 start, u64 end);
242void btrfs_readahead(struct readahead_control *rac);
243int set_folio_extent_mapped(struct folio *folio);
244void clear_folio_extent_mapped(struct folio *folio);
245
246struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
247 u64 start, u64 owner_root, int level);
248struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
249 u64 start);
250struct extent_buffer *btrfs_clone_extent_buffer(const struct extent_buffer *src);
251struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
252 u64 start);
253void free_extent_buffer(struct extent_buffer *eb);
254void free_extent_buffer_stale(struct extent_buffer *eb);
255int read_extent_buffer_pages(struct extent_buffer *eb, int mirror_num,
256 const struct btrfs_tree_parent_check *parent_check);
257int read_extent_buffer_pages_nowait(struct extent_buffer *eb, int mirror_num,
258 const struct btrfs_tree_parent_check *parent_check);
259
260static inline void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
261{
262 wait_on_bit_io(word: &eb->bflags, bit: EXTENT_BUFFER_WRITEBACK,
263 TASK_UNINTERRUPTIBLE);
264}
265
266void btrfs_readahead_tree_block(struct btrfs_fs_info *fs_info,
267 u64 bytenr, u64 owner_root, u64 gen, int level);
268void btrfs_readahead_node_child(struct extent_buffer *node, int slot);
269
270/* Note: this can be used in for loops without caching the value in a variable. */
271static inline int __pure num_extent_pages(const struct extent_buffer *eb)
272{
273 /*
274 * For sectorsize == PAGE_SIZE case, since nodesize is always aligned to
275 * sectorsize, it's just eb->len >> PAGE_SHIFT.
276 *
277 * For sectorsize < PAGE_SIZE case, we could have nodesize < PAGE_SIZE,
278 * thus have to ensure we get at least one page.
279 */
280 return (eb->len >> PAGE_SHIFT) ?: 1;
281}
282
283/*
284 * This can only be determined at runtime by checking eb::folios[0].
285 *
286 * As we can have either one large folio covering the whole eb
287 * (either nodesize <= PAGE_SIZE, or high order folio), or multiple
288 * single-paged folios.
289 *
290 * Note: this can be used in for loops without caching the value in a variable.
291 */
292static inline int __pure num_extent_folios(const struct extent_buffer *eb)
293{
294 if (!eb->folios[0])
295 return 0;
296 if (folio_order(folio: eb->folios[0]))
297 return 1;
298 return num_extent_pages(eb);
299}
300
301static inline int extent_buffer_uptodate(const struct extent_buffer *eb)
302{
303 return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
304}
305
306int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
307 unsigned long start, unsigned long len);
308void read_extent_buffer(const struct extent_buffer *eb, void *dst,
309 unsigned long start,
310 unsigned long len);
311int read_extent_buffer_to_user_nofault(const struct extent_buffer *eb,
312 void __user *dst, unsigned long start,
313 unsigned long len);
314void write_extent_buffer(const struct extent_buffer *eb, const void *src,
315 unsigned long start, unsigned long len);
316
317static inline void write_extent_buffer_chunk_tree_uuid(
318 const struct extent_buffer *eb, const void *chunk_tree_uuid)
319{
320 write_extent_buffer(eb, src: chunk_tree_uuid,
321 offsetof(struct btrfs_header, chunk_tree_uuid),
322 BTRFS_FSID_SIZE);
323}
324
325static inline void write_extent_buffer_fsid(const struct extent_buffer *eb,
326 const void *fsid)
327{
328 write_extent_buffer(eb, src: fsid, offsetof(struct btrfs_header, fsid),
329 BTRFS_FSID_SIZE);
330}
331
332void copy_extent_buffer_full(const struct extent_buffer *dst,
333 const struct extent_buffer *src);
334void copy_extent_buffer(const struct extent_buffer *dst,
335 const struct extent_buffer *src,
336 unsigned long dst_offset, unsigned long src_offset,
337 unsigned long len);
338void memcpy_extent_buffer(const struct extent_buffer *dst,
339 unsigned long dst_offset, unsigned long src_offset,
340 unsigned long len);
341void memmove_extent_buffer(const struct extent_buffer *dst,
342 unsigned long dst_offset, unsigned long src_offset,
343 unsigned long len);
344void memzero_extent_buffer(const struct extent_buffer *eb, unsigned long start,
345 unsigned long len);
346bool extent_buffer_test_bit(const struct extent_buffer *eb, unsigned long start,
347 unsigned long pos);
348void extent_buffer_bitmap_set(const struct extent_buffer *eb, unsigned long start,
349 unsigned long pos, unsigned long len);
350void extent_buffer_bitmap_clear(const struct extent_buffer *eb,
351 unsigned long start, unsigned long pos,
352 unsigned long len);
353void set_extent_buffer_dirty(struct extent_buffer *eb);
354void set_extent_buffer_uptodate(struct extent_buffer *eb);
355void clear_extent_buffer_uptodate(struct extent_buffer *eb);
356void extent_clear_unlock_delalloc(struct btrfs_inode *inode, u64 start, u64 end,
357 const struct folio *locked_folio,
358 struct extent_state **cached,
359 u32 bits_to_clear, unsigned long page_ops);
360int extent_invalidate_folio(struct extent_io_tree *tree,
361 struct folio *folio, size_t offset);
362void btrfs_clear_buffer_dirty(struct btrfs_trans_handle *trans,
363 struct extent_buffer *buf);
364
365int btrfs_alloc_page_array(unsigned int nr_pages, struct page **page_array,
366 bool nofail);
367int btrfs_alloc_folio_array(unsigned int nr_folios, unsigned int order,
368 struct folio **folio_array);
369
370#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
371bool find_lock_delalloc_range(struct inode *inode,
372 struct folio *locked_folio, u64 *start,
373 u64 *end);
374#endif
375struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
376 u64 start);
377
378#ifdef CONFIG_BTRFS_DEBUG
379void btrfs_extent_buffer_leak_debug_check(struct btrfs_fs_info *fs_info);
380#else
381#define btrfs_extent_buffer_leak_debug_check(fs_info) do {} while (0)
382#endif
383
384#endif
385

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