xref: /linux/fs/btrfs/extent_io.h (revision e3fc2fd77c63cd2e37ebd33a336602a68650f22b)
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 
20 struct page;
21 struct file;
22 struct folio;
23 struct inode;
24 struct fiemap_extent_info;
25 struct readahead_control;
26 struct address_space;
27 struct writeback_control;
28 struct extent_io_tree;
29 struct extent_map_tree;
30 struct extent_state;
31 struct btrfs_block_group;
32 struct btrfs_fs_info;
33 struct btrfs_inode;
34 struct btrfs_root;
35 struct btrfs_trans_handle;
36 struct btrfs_tree_parent_check;
37 
38 enum {
39 	EXTENT_BUFFER_UPTODATE,
40 	EXTENT_BUFFER_DIRTY,
41 	EXTENT_BUFFER_CORRUPT,
42 	/* this got triggered by readahead */
43 	EXTENT_BUFFER_READAHEAD,
44 	EXTENT_BUFFER_TREE_REF,
45 	EXTENT_BUFFER_STALE,
46 	EXTENT_BUFFER_WRITEBACK,
47 	/* read IO error */
48 	EXTENT_BUFFER_READ_ERR,
49 	EXTENT_BUFFER_UNMAPPED,
50 	EXTENT_BUFFER_IN_TREE,
51 	/* write IO error */
52 	EXTENT_BUFFER_WRITE_ERR,
53 	/* Indicate the extent buffer is written zeroed out (for zoned) */
54 	EXTENT_BUFFER_ZONED_ZEROOUT,
55 	/* Indicate that extent buffer pages a being read */
56 	EXTENT_BUFFER_READING,
57 };
58 
59 /* these are flags for __process_pages_contig */
60 enum {
61 	ENUM_BIT(PAGE_UNLOCK),
62 	/* Page starts writeback, clear dirty bit and set writeback bit */
63 	ENUM_BIT(PAGE_START_WRITEBACK),
64 	ENUM_BIT(PAGE_END_WRITEBACK),
65 	ENUM_BIT(PAGE_SET_ORDERED),
66 };
67 
68 /*
69  * Folio private values.  Every page that is controlled by the extent map has
70  * folio private set to this value.
71  */
72 #define EXTENT_FOLIO_PRIVATE			1
73 
74 /*
75  * The extent buffer bitmap operations are done with byte granularity instead of
76  * word granularity for two reasons:
77  * 1. The bitmaps must be little-endian on disk.
78  * 2. Bitmap items are not guaranteed to be aligned to a word and therefore a
79  *    single word in a bitmap may straddle two pages in the extent buffer.
80  */
81 #define BIT_BYTE(nr) ((nr) / BITS_PER_BYTE)
82 #define BYTE_MASK ((1 << BITS_PER_BYTE) - 1)
83 #define BITMAP_FIRST_BYTE_MASK(start) \
84 	((BYTE_MASK << ((start) & (BITS_PER_BYTE - 1))) & BYTE_MASK)
85 #define BITMAP_LAST_BYTE_MASK(nbits) \
86 	(BYTE_MASK >> (-(nbits) & (BITS_PER_BYTE - 1)))
87 
88 
89 int __init extent_buffer_init_cachep(void);
90 void __cold extent_buffer_free_cachep(void);
91 
92 #define INLINE_EXTENT_BUFFER_PAGES     (BTRFS_MAX_METADATA_BLOCKSIZE / PAGE_SIZE)
93 struct extent_buffer {
94 	u64 start;
95 	u32 len;
96 	u32 folio_size;
97 	unsigned long bflags;
98 	struct btrfs_fs_info *fs_info;
99 
100 	/*
101 	 * The address where the eb can be accessed without any cross-page handling.
102 	 * This can be NULL if not possible.
103 	 */
104 	void *addr;
105 
106 	spinlock_t refs_lock;
107 	atomic_t refs;
108 	int read_mirror;
109 	/* >= 0 if eb belongs to a log tree, -1 otherwise */
110 	s8 log_index;
111 	u8 folio_shift;
112 	struct rcu_head rcu_head;
113 
114 	struct rw_semaphore lock;
115 
116 	/*
117 	 * Pointers to all the folios of the extent buffer.
118 	 *
119 	 * For now the folio is always order 0 (aka, a single page).
120 	 */
121 	struct folio *folios[INLINE_EXTENT_BUFFER_PAGES];
122 #ifdef CONFIG_BTRFS_DEBUG
123 	struct list_head leak_list;
124 	pid_t lock_owner;
125 #endif
126 };
127 
128 struct btrfs_eb_write_context {
129 	struct writeback_control *wbc;
130 	struct extent_buffer *eb;
131 	/* Block group @eb resides in. Only used for zoned mode. */
132 	struct btrfs_block_group *zoned_bg;
133 };
134 
135 static inline unsigned long offset_in_eb_folio(const struct extent_buffer *eb,
136 					       u64 start)
137 {
138 	ASSERT(eb->folio_size);
139 	return start & (eb->folio_size - 1);
140 }
141 
142 /*
143  * Get the correct offset inside the page of extent buffer.
144  *
145  * @eb:		target extent buffer
146  * @start:	offset inside the extent buffer
147  *
148  * Will handle both sectorsize == PAGE_SIZE and sectorsize < PAGE_SIZE cases.
149  */
150 static inline size_t get_eb_offset_in_folio(const struct extent_buffer *eb,
151 					    unsigned long offset)
152 {
153 	/*
154 	 * 1) sectorsize == PAGE_SIZE and nodesize >= PAGE_SIZE case
155 	 *    1.1) One large folio covering the whole eb
156 	 *	   The eb->start is aligned to folio size, thus adding it
157 	 *	   won't cause any difference.
158 	 *    1.2) Several page sized folios
159 	 *	   The eb->start is aligned to folio (page) size, thus
160 	 *	   adding it won't cause any difference.
161 	 *
162 	 * 2) sectorsize < PAGE_SIZE and nodesize < PAGE_SIZE case
163 	 *    In this case there would only be one page sized folio, and there
164 	 *    may be several different extent buffers in the page/folio.
165 	 *    We need to add eb->start to properly access the offset inside
166 	 *    that eb.
167 	 */
168 	return offset_in_folio(eb->folios[0], offset + eb->start);
169 }
170 
171 static inline unsigned long get_eb_folio_index(const struct extent_buffer *eb,
172 					       unsigned long offset)
173 {
174 	/*
175 	 * 1) sectorsize == PAGE_SIZE and nodesize >= PAGE_SIZE case
176 	 *    1.1) One large folio covering the whole eb.
177 	 *	   the folio_shift would be large enough to always make us
178 	 *	   return 0 as index.
179 	 *    1.2) Several page sized folios
180 	 *         The folio_shift would be PAGE_SHIFT, giving us the correct
181 	 *         index.
182 	 *
183 	 * 2) sectorsize < PAGE_SIZE and nodesize < PAGE_SIZE case
184 	 *    The folio would only be page sized, and always give us 0 as index.
185 	 */
186 	return offset >> eb->folio_shift;
187 }
188 
189 /*
190  * Structure to record how many bytes and which ranges are set/cleared
191  */
192 struct extent_changeset {
193 	/* How many bytes are set/cleared in this operation */
194 	u64 bytes_changed;
195 
196 	/* Changed ranges */
197 	struct ulist range_changed;
198 };
199 
200 static inline void extent_changeset_init(struct extent_changeset *changeset)
201 {
202 	changeset->bytes_changed = 0;
203 	ulist_init(&changeset->range_changed);
204 }
205 
206 static inline struct extent_changeset *extent_changeset_alloc(void)
207 {
208 	struct extent_changeset *ret;
209 
210 	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
211 	if (!ret)
212 		return NULL;
213 
214 	extent_changeset_init(ret);
215 	return ret;
216 }
217 
218 static inline void extent_changeset_prealloc(struct extent_changeset *changeset, gfp_t gfp_mask)
219 {
220 	ulist_prealloc(&changeset->range_changed, gfp_mask);
221 }
222 
223 static inline void extent_changeset_release(struct extent_changeset *changeset)
224 {
225 	if (!changeset)
226 		return;
227 	changeset->bytes_changed = 0;
228 	ulist_release(&changeset->range_changed);
229 }
230 
231 static inline void extent_changeset_free(struct extent_changeset *changeset)
232 {
233 	if (!changeset)
234 		return;
235 	extent_changeset_release(changeset);
236 	kfree(changeset);
237 }
238 
239 bool try_release_extent_mapping(struct folio *folio, gfp_t mask);
240 int try_release_extent_buffer(struct folio *folio);
241 
242 int btrfs_read_folio(struct file *file, struct folio *folio);
243 void extent_write_locked_range(struct inode *inode, const struct folio *locked_folio,
244 			       u64 start, u64 end, struct writeback_control *wbc,
245 			       bool pages_dirty);
246 int btrfs_writepages(struct address_space *mapping, struct writeback_control *wbc);
247 int btree_write_cache_pages(struct address_space *mapping,
248 			    struct writeback_control *wbc);
249 void btrfs_readahead(struct readahead_control *rac);
250 int set_folio_extent_mapped(struct folio *folio);
251 int set_page_extent_mapped(struct page *page);
252 void clear_folio_extent_mapped(struct folio *folio);
253 
254 struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
255 					  u64 start, u64 owner_root, int level);
256 struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
257 						  u64 start, unsigned long len);
258 struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
259 						u64 start);
260 struct extent_buffer *btrfs_clone_extent_buffer(const struct extent_buffer *src);
261 struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
262 					 u64 start);
263 void free_extent_buffer(struct extent_buffer *eb);
264 void free_extent_buffer_stale(struct extent_buffer *eb);
265 #define WAIT_NONE	0
266 #define WAIT_COMPLETE	1
267 #define WAIT_PAGE_LOCK	2
268 int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
269 			     const struct btrfs_tree_parent_check *parent_check);
270 void wait_on_extent_buffer_writeback(struct extent_buffer *eb);
271 void btrfs_readahead_tree_block(struct btrfs_fs_info *fs_info,
272 				u64 bytenr, u64 owner_root, u64 gen, int level);
273 void btrfs_readahead_node_child(struct extent_buffer *node, int slot);
274 
275 static inline int num_extent_pages(const struct extent_buffer *eb)
276 {
277 	/*
278 	 * For sectorsize == PAGE_SIZE case, since nodesize is always aligned to
279 	 * sectorsize, it's just eb->len >> PAGE_SHIFT.
280 	 *
281 	 * For sectorsize < PAGE_SIZE case, we could have nodesize < PAGE_SIZE,
282 	 * thus have to ensure we get at least one page.
283 	 */
284 	return (eb->len >> PAGE_SHIFT) ?: 1;
285 }
286 
287 /*
288  * This can only be determined at runtime by checking eb::folios[0].
289  *
290  * As we can have either one large folio covering the whole eb
291  * (either nodesize <= PAGE_SIZE, or high order folio), or multiple
292  * single-paged folios.
293  */
294 static inline int num_extent_folios(const struct extent_buffer *eb)
295 {
296 	if (folio_order(eb->folios[0]))
297 		return 1;
298 	return num_extent_pages(eb);
299 }
300 
301 static inline int extent_buffer_uptodate(const struct extent_buffer *eb)
302 {
303 	return test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
304 }
305 
306 int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
307 			 unsigned long start, unsigned long len);
308 void read_extent_buffer(const struct extent_buffer *eb, void *dst,
309 			unsigned long start,
310 			unsigned long len);
311 int read_extent_buffer_to_user_nofault(const struct extent_buffer *eb,
312 				       void __user *dst, unsigned long start,
313 				       unsigned long len);
314 void write_extent_buffer(const struct extent_buffer *eb, const void *src,
315 			 unsigned long start, unsigned long len);
316 
317 static 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, chunk_tree_uuid,
321 			    offsetof(struct btrfs_header, chunk_tree_uuid),
322 			    BTRFS_FSID_SIZE);
323 }
324 
325 static inline void write_extent_buffer_fsid(const struct extent_buffer *eb,
326 					    const void *fsid)
327 {
328 	write_extent_buffer(eb, fsid, offsetof(struct btrfs_header, fsid),
329 			    BTRFS_FSID_SIZE);
330 }
331 
332 void copy_extent_buffer_full(const struct extent_buffer *dst,
333 			     const struct extent_buffer *src);
334 void 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);
338 void memcpy_extent_buffer(const struct extent_buffer *dst,
339 			  unsigned long dst_offset, unsigned long src_offset,
340 			  unsigned long len);
341 void memmove_extent_buffer(const struct extent_buffer *dst,
342 			   unsigned long dst_offset, unsigned long src_offset,
343 			   unsigned long len);
344 void memzero_extent_buffer(const struct extent_buffer *eb, unsigned long start,
345 			   unsigned long len);
346 int extent_buffer_test_bit(const struct extent_buffer *eb, unsigned long start,
347 			   unsigned long pos);
348 void extent_buffer_bitmap_set(const struct extent_buffer *eb, unsigned long start,
349 			      unsigned long pos, unsigned long len);
350 void extent_buffer_bitmap_clear(const struct extent_buffer *eb,
351 				unsigned long start, unsigned long pos,
352 				unsigned long len);
353 void set_extent_buffer_dirty(struct extent_buffer *eb);
354 void set_extent_buffer_uptodate(struct extent_buffer *eb);
355 void clear_extent_buffer_uptodate(struct extent_buffer *eb);
356 void 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);
360 int extent_invalidate_folio(struct extent_io_tree *tree,
361 			    struct folio *folio, size_t offset);
362 void btrfs_clear_buffer_dirty(struct btrfs_trans_handle *trans,
363 			      struct extent_buffer *buf);
364 
365 int btrfs_alloc_page_array(unsigned int nr_pages, struct page **page_array,
366 			   bool nofail);
367 int btrfs_alloc_folio_array(unsigned int nr_folios, struct folio **folio_array);
368 
369 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
370 bool find_lock_delalloc_range(struct inode *inode,
371 			      struct folio *locked_folio, u64 *start,
372 			     u64 *end);
373 #endif
374 struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
375 					       u64 start);
376 
377 #ifdef CONFIG_BTRFS_DEBUG
378 void btrfs_extent_buffer_leak_debug_check(struct btrfs_fs_info *fs_info);
379 #else
380 #define btrfs_extent_buffer_leak_debug_check(fs_info)	do {} while (0)
381 #endif
382 
383 #endif
384