xref: /linux/fs/btrfs/ctree.h (revision 72bea132f3680ee51e7ed2cee62892b6f5121909)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Copyright (C) 2007 Oracle.  All rights reserved.
4  */
5 
6 #ifndef BTRFS_CTREE_H
7 #define BTRFS_CTREE_H
8 
9 #include <linux/pagemap.h>
10 #include <linux/spinlock.h>
11 #include <linux/rbtree.h>
12 #include <linux/mutex.h>
13 #include <linux/wait.h>
14 #include <linux/list.h>
15 #include <linux/atomic.h>
16 #include <linux/xarray.h>
17 #include <linux/refcount.h>
18 #include <uapi/linux/btrfs_tree.h>
19 #include "locking.h"
20 #include "fs.h"
21 #include "accessors.h"
22 #include "extent-io-tree.h"
23 
24 struct extent_buffer;
25 struct btrfs_block_rsv;
26 struct btrfs_trans_handle;
27 struct btrfs_block_group;
28 
29 /* Read ahead values for struct btrfs_path.reada */
30 enum {
31 	READA_NONE,
32 	READA_BACK,
33 	READA_FORWARD,
34 	/*
35 	 * Similar to READA_FORWARD but unlike it:
36 	 *
37 	 * 1) It will trigger readahead even for leaves that are not close to
38 	 *    each other on disk;
39 	 * 2) It also triggers readahead for nodes;
40 	 * 3) During a search, even when a node or leaf is already in memory, it
41 	 *    will still trigger readahead for other nodes and leaves that follow
42 	 *    it.
43 	 *
44 	 * This is meant to be used only when we know we are iterating over the
45 	 * entire tree or a very large part of it.
46 	 */
47 	READA_FORWARD_ALWAYS,
48 };
49 
50 /*
51  * btrfs_paths remember the path taken from the root down to the leaf.
52  * level 0 is always the leaf, and nodes[1...BTRFS_MAX_LEVEL] will point
53  * to any other levels that are present.
54  *
55  * The slots array records the index of the item or block pointer
56  * used while walking the tree.
57  */
58 struct btrfs_path {
59 	struct extent_buffer *nodes[BTRFS_MAX_LEVEL];
60 	int slots[BTRFS_MAX_LEVEL];
61 	/* if there is real range locking, this locks field will change */
62 	u8 locks[BTRFS_MAX_LEVEL];
63 	u8 reada;
64 	/* keep some upper locks as we walk down */
65 	u8 lowest_level;
66 
67 	/*
68 	 * set by btrfs_split_item, tells search_slot to keep all locks
69 	 * and to force calls to keep space in the nodes
70 	 */
71 	unsigned int search_for_split:1;
72 	unsigned int keep_locks:1;
73 	unsigned int skip_locking:1;
74 	unsigned int search_commit_root:1;
75 	unsigned int need_commit_sem:1;
76 	unsigned int skip_release_on_error:1;
77 	/*
78 	 * Indicate that new item (btrfs_search_slot) is extending already
79 	 * existing item and ins_len contains only the data size and not item
80 	 * header (ie. sizeof(struct btrfs_item) is not included).
81 	 */
82 	unsigned int search_for_extension:1;
83 	/* Stop search if any locks need to be taken (for read) */
84 	unsigned int nowait:1;
85 };
86 
87 /*
88  * The state of btrfs root
89  */
90 enum {
91 	/*
92 	 * btrfs_record_root_in_trans is a multi-step process, and it can race
93 	 * with the balancing code.   But the race is very small, and only the
94 	 * first time the root is added to each transaction.  So IN_TRANS_SETUP
95 	 * is used to tell us when more checks are required
96 	 */
97 	BTRFS_ROOT_IN_TRANS_SETUP,
98 
99 	/*
100 	 * Set if tree blocks of this root can be shared by other roots.
101 	 * Only subvolume trees and their reloc trees have this bit set.
102 	 * Conflicts with TRACK_DIRTY bit.
103 	 *
104 	 * This affects two things:
105 	 *
106 	 * - How balance works
107 	 *   For shareable roots, we need to use reloc tree and do path
108 	 *   replacement for balance, and need various pre/post hooks for
109 	 *   snapshot creation to handle them.
110 	 *
111 	 *   While for non-shareable trees, we just simply do a tree search
112 	 *   with COW.
113 	 *
114 	 * - How dirty roots are tracked
115 	 *   For shareable roots, btrfs_record_root_in_trans() is needed to
116 	 *   track them, while non-subvolume roots have TRACK_DIRTY bit, they
117 	 *   don't need to set this manually.
118 	 */
119 	BTRFS_ROOT_SHAREABLE,
120 	BTRFS_ROOT_TRACK_DIRTY,
121 	BTRFS_ROOT_IN_RADIX,
122 	BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
123 	BTRFS_ROOT_DEFRAG_RUNNING,
124 	BTRFS_ROOT_FORCE_COW,
125 	BTRFS_ROOT_MULTI_LOG_TASKS,
126 	BTRFS_ROOT_DIRTY,
127 	BTRFS_ROOT_DELETING,
128 
129 	/*
130 	 * Reloc tree is orphan, only kept here for qgroup delayed subtree scan
131 	 *
132 	 * Set for the subvolume tree owning the reloc tree.
133 	 */
134 	BTRFS_ROOT_DEAD_RELOC_TREE,
135 	/* Mark dead root stored on device whose cleanup needs to be resumed */
136 	BTRFS_ROOT_DEAD_TREE,
137 	/* The root has a log tree. Used for subvolume roots and the tree root. */
138 	BTRFS_ROOT_HAS_LOG_TREE,
139 	/* Qgroup flushing is in progress */
140 	BTRFS_ROOT_QGROUP_FLUSHING,
141 	/* We started the orphan cleanup for this root. */
142 	BTRFS_ROOT_ORPHAN_CLEANUP,
143 	/* This root has a drop operation that was started previously. */
144 	BTRFS_ROOT_UNFINISHED_DROP,
145 	/* This reloc root needs to have its buffers lockdep class reset. */
146 	BTRFS_ROOT_RESET_LOCKDEP_CLASS,
147 };
148 
149 /*
150  * Record swapped tree blocks of a subvolume tree for delayed subtree trace
151  * code. For detail check comment in fs/btrfs/qgroup.c.
152  */
153 struct btrfs_qgroup_swapped_blocks {
154 	spinlock_t lock;
155 	/* RM_EMPTY_ROOT() of above blocks[] */
156 	bool swapped;
157 	struct rb_root blocks[BTRFS_MAX_LEVEL];
158 };
159 
160 /*
161  * in ram representation of the tree.  extent_root is used for all allocations
162  * and for the extent tree extent_root root.
163  */
164 struct btrfs_root {
165 	struct rb_node rb_node;
166 
167 	struct extent_buffer *node;
168 
169 	struct extent_buffer *commit_root;
170 	struct btrfs_root *log_root;
171 	struct btrfs_root *reloc_root;
172 
173 	unsigned long state;
174 	struct btrfs_root_item root_item;
175 	struct btrfs_key root_key;
176 	struct btrfs_fs_info *fs_info;
177 	struct extent_io_tree dirty_log_pages;
178 
179 	struct mutex objectid_mutex;
180 
181 	spinlock_t accounting_lock;
182 	struct btrfs_block_rsv *block_rsv;
183 
184 	struct mutex log_mutex;
185 	wait_queue_head_t log_writer_wait;
186 	wait_queue_head_t log_commit_wait[2];
187 	struct list_head log_ctxs[2];
188 	/* Used only for log trees of subvolumes, not for the log root tree */
189 	atomic_t log_writers;
190 	atomic_t log_commit[2];
191 	/* Used only for log trees of subvolumes, not for the log root tree */
192 	atomic_t log_batch;
193 	/*
194 	 * Protected by the 'log_mutex' lock but can be read without holding
195 	 * that lock to avoid unnecessary lock contention, in which case it
196 	 * should be read using btrfs_get_root_log_transid() except if it's a
197 	 * log tree in which case it can be directly accessed. Updates to this
198 	 * field should always use btrfs_set_root_log_transid(), except for log
199 	 * trees where the field can be updated directly.
200 	 */
201 	int log_transid;
202 	/* No matter the commit succeeds or not*/
203 	int log_transid_committed;
204 	/*
205 	 * Just be updated when the commit succeeds. Use
206 	 * btrfs_get_root_last_log_commit() and btrfs_set_root_last_log_commit()
207 	 * to access this field.
208 	 */
209 	int last_log_commit;
210 	pid_t log_start_pid;
211 
212 	u64 last_trans;
213 
214 	u64 free_objectid;
215 
216 	struct btrfs_key defrag_progress;
217 	struct btrfs_key defrag_max;
218 
219 	/* The dirty list is only used by non-shareable roots */
220 	struct list_head dirty_list;
221 
222 	struct list_head root_list;
223 
224 	spinlock_t inode_lock;
225 	/* red-black tree that keeps track of in-memory inodes */
226 	struct rb_root inode_tree;
227 
228 	/*
229 	 * Xarray that keeps track of delayed nodes of every inode, protected
230 	 * by @inode_lock.
231 	 */
232 	struct xarray delayed_nodes;
233 	/*
234 	 * right now this just gets used so that a root has its own devid
235 	 * for stat.  It may be used for more later
236 	 */
237 	dev_t anon_dev;
238 
239 	spinlock_t root_item_lock;
240 	refcount_t refs;
241 
242 	struct mutex delalloc_mutex;
243 	spinlock_t delalloc_lock;
244 	/*
245 	 * all of the inodes that have delalloc bytes.  It is possible for
246 	 * this list to be empty even when there is still dirty data=ordered
247 	 * extents waiting to finish IO.
248 	 */
249 	struct list_head delalloc_inodes;
250 	struct list_head delalloc_root;
251 	u64 nr_delalloc_inodes;
252 
253 	struct mutex ordered_extent_mutex;
254 	/*
255 	 * this is used by the balancing code to wait for all the pending
256 	 * ordered extents
257 	 */
258 	spinlock_t ordered_extent_lock;
259 
260 	/*
261 	 * all of the data=ordered extents pending writeback
262 	 * these can span multiple transactions and basically include
263 	 * every dirty data page that isn't from nodatacow
264 	 */
265 	struct list_head ordered_extents;
266 	struct list_head ordered_root;
267 	u64 nr_ordered_extents;
268 
269 	/*
270 	 * Not empty if this subvolume root has gone through tree block swap
271 	 * (relocation)
272 	 *
273 	 * Will be used by reloc_control::dirty_subvol_roots.
274 	 */
275 	struct list_head reloc_dirty_list;
276 
277 	/*
278 	 * Number of currently running SEND ioctls to prevent
279 	 * manipulation with the read-only status via SUBVOL_SETFLAGS
280 	 */
281 	int send_in_progress;
282 	/*
283 	 * Number of currently running deduplication operations that have a
284 	 * destination inode belonging to this root. Protected by the lock
285 	 * root_item_lock.
286 	 */
287 	int dedupe_in_progress;
288 	/* For exclusion of snapshot creation and nocow writes */
289 	struct btrfs_drew_lock snapshot_lock;
290 
291 	atomic_t snapshot_force_cow;
292 
293 	/* For qgroup metadata reserved space */
294 	spinlock_t qgroup_meta_rsv_lock;
295 	u64 qgroup_meta_rsv_pertrans;
296 	u64 qgroup_meta_rsv_prealloc;
297 	wait_queue_head_t qgroup_flush_wait;
298 
299 	/* Number of active swapfiles */
300 	atomic_t nr_swapfiles;
301 
302 	/* Record pairs of swapped blocks for qgroup */
303 	struct btrfs_qgroup_swapped_blocks swapped_blocks;
304 
305 	/* Used only by log trees, when logging csum items */
306 	struct extent_io_tree log_csum_range;
307 
308 	/* Used in simple quotas, track root during relocation. */
309 	u64 relocation_src_root;
310 
311 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
312 	u64 alloc_bytenr;
313 #endif
314 
315 #ifdef CONFIG_BTRFS_DEBUG
316 	struct list_head leak_list;
317 #endif
318 };
319 
320 static inline bool btrfs_root_readonly(const struct btrfs_root *root)
321 {
322 	/* Byte-swap the constant at compile time, root_item::flags is LE */
323 	return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_RDONLY)) != 0;
324 }
325 
326 static inline bool btrfs_root_dead(const struct btrfs_root *root)
327 {
328 	/* Byte-swap the constant at compile time, root_item::flags is LE */
329 	return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_DEAD)) != 0;
330 }
331 
332 static inline u64 btrfs_root_id(const struct btrfs_root *root)
333 {
334 	return root->root_key.objectid;
335 }
336 
337 static inline int btrfs_get_root_log_transid(const struct btrfs_root *root)
338 {
339 	return READ_ONCE(root->log_transid);
340 }
341 
342 static inline void btrfs_set_root_log_transid(struct btrfs_root *root, int log_transid)
343 {
344 	WRITE_ONCE(root->log_transid, log_transid);
345 }
346 
347 static inline int btrfs_get_root_last_log_commit(const struct btrfs_root *root)
348 {
349 	return READ_ONCE(root->last_log_commit);
350 }
351 
352 static inline void btrfs_set_root_last_log_commit(struct btrfs_root *root, int commit_id)
353 {
354 	WRITE_ONCE(root->last_log_commit, commit_id);
355 }
356 
357 /*
358  * Structure that conveys information about an extent that is going to replace
359  * all the extents in a file range.
360  */
361 struct btrfs_replace_extent_info {
362 	u64 disk_offset;
363 	u64 disk_len;
364 	u64 data_offset;
365 	u64 data_len;
366 	u64 file_offset;
367 	/* Pointer to a file extent item of type regular or prealloc. */
368 	char *extent_buf;
369 	/*
370 	 * Set to true when attempting to replace a file range with a new extent
371 	 * described by this structure, set to false when attempting to clone an
372 	 * existing extent into a file range.
373 	 */
374 	bool is_new_extent;
375 	/* Indicate if we should update the inode's mtime and ctime. */
376 	bool update_times;
377 	/* Meaningful only if is_new_extent is true. */
378 	int qgroup_reserved;
379 	/*
380 	 * Meaningful only if is_new_extent is true.
381 	 * Used to track how many extent items we have already inserted in a
382 	 * subvolume tree that refer to the extent described by this structure,
383 	 * so that we know when to create a new delayed ref or update an existing
384 	 * one.
385 	 */
386 	int insertions;
387 };
388 
389 /* Arguments for btrfs_drop_extents() */
390 struct btrfs_drop_extents_args {
391 	/* Input parameters */
392 
393 	/*
394 	 * If NULL, btrfs_drop_extents() will allocate and free its own path.
395 	 * If 'replace_extent' is true, this must not be NULL. Also the path
396 	 * is always released except if 'replace_extent' is true and
397 	 * btrfs_drop_extents() sets 'extent_inserted' to true, in which case
398 	 * the path is kept locked.
399 	 */
400 	struct btrfs_path *path;
401 	/* Start offset of the range to drop extents from */
402 	u64 start;
403 	/* End (exclusive, last byte + 1) of the range to drop extents from */
404 	u64 end;
405 	/* If true drop all the extent maps in the range */
406 	bool drop_cache;
407 	/*
408 	 * If true it means we want to insert a new extent after dropping all
409 	 * the extents in the range. If this is true, the 'extent_item_size'
410 	 * parameter must be set as well and the 'extent_inserted' field will
411 	 * be set to true by btrfs_drop_extents() if it could insert the new
412 	 * extent.
413 	 * Note: when this is set to true the path must not be NULL.
414 	 */
415 	bool replace_extent;
416 	/*
417 	 * Used if 'replace_extent' is true. Size of the file extent item to
418 	 * insert after dropping all existing extents in the range
419 	 */
420 	u32 extent_item_size;
421 
422 	/* Output parameters */
423 
424 	/*
425 	 * Set to the minimum between the input parameter 'end' and the end
426 	 * (exclusive, last byte + 1) of the last dropped extent. This is always
427 	 * set even if btrfs_drop_extents() returns an error.
428 	 */
429 	u64 drop_end;
430 	/*
431 	 * The number of allocated bytes found in the range. This can be smaller
432 	 * than the range's length when there are holes in the range.
433 	 */
434 	u64 bytes_found;
435 	/*
436 	 * Only set if 'replace_extent' is true. Set to true if we were able
437 	 * to insert a replacement extent after dropping all extents in the
438 	 * range, otherwise set to false by btrfs_drop_extents().
439 	 * Also, if btrfs_drop_extents() has set this to true it means it
440 	 * returned with the path locked, otherwise if it has set this to
441 	 * false it has returned with the path released.
442 	 */
443 	bool extent_inserted;
444 };
445 
446 struct btrfs_file_private {
447 	void *filldir_buf;
448 	u64 last_index;
449 	struct extent_state *llseek_cached_state;
450 };
451 
452 static inline u32 BTRFS_LEAF_DATA_SIZE(const struct btrfs_fs_info *info)
453 {
454 	return info->nodesize - sizeof(struct btrfs_header);
455 }
456 
457 static inline u32 BTRFS_MAX_ITEM_SIZE(const struct btrfs_fs_info *info)
458 {
459 	return BTRFS_LEAF_DATA_SIZE(info) - sizeof(struct btrfs_item);
460 }
461 
462 static inline u32 BTRFS_NODEPTRS_PER_BLOCK(const struct btrfs_fs_info *info)
463 {
464 	return BTRFS_LEAF_DATA_SIZE(info) / sizeof(struct btrfs_key_ptr);
465 }
466 
467 static inline u32 BTRFS_MAX_XATTR_SIZE(const struct btrfs_fs_info *info)
468 {
469 	return BTRFS_MAX_ITEM_SIZE(info) - sizeof(struct btrfs_dir_item);
470 }
471 
472 #define BTRFS_BYTES_TO_BLKS(fs_info, bytes) \
473 				((bytes) >> (fs_info)->sectorsize_bits)
474 
475 static inline gfp_t btrfs_alloc_write_mask(struct address_space *mapping)
476 {
477 	return mapping_gfp_constraint(mapping, ~__GFP_FS);
478 }
479 
480 void btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info, u64 start, u64 end);
481 int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
482 			 u64 num_bytes, u64 *actual_bytes);
483 int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range);
484 
485 /* ctree.c */
486 int __init btrfs_ctree_init(void);
487 void __cold btrfs_ctree_exit(void);
488 
489 int btrfs_bin_search(struct extent_buffer *eb, int first_slot,
490 		     const struct btrfs_key *key, int *slot);
491 
492 int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2);
493 
494 #ifdef __LITTLE_ENDIAN
495 
496 /*
497  * Compare two keys, on little-endian the disk order is same as CPU order and
498  * we can avoid the conversion.
499  */
500 static inline int btrfs_comp_keys(const struct btrfs_disk_key *disk_key,
501 				  const struct btrfs_key *k2)
502 {
503 	const struct btrfs_key *k1 = (const struct btrfs_key *)disk_key;
504 
505 	return btrfs_comp_cpu_keys(k1, k2);
506 }
507 
508 #else
509 
510 /* Compare two keys in a memcmp fashion. */
511 static inline int btrfs_comp_keys(const struct btrfs_disk_key *disk,
512 				  const struct btrfs_key *k2)
513 {
514 	struct btrfs_key k1;
515 
516 	btrfs_disk_key_to_cpu(&k1, disk);
517 
518 	return btrfs_comp_cpu_keys(&k1, k2);
519 }
520 
521 #endif
522 
523 int btrfs_previous_item(struct btrfs_root *root,
524 			struct btrfs_path *path, u64 min_objectid,
525 			int type);
526 int btrfs_previous_extent_item(struct btrfs_root *root,
527 			struct btrfs_path *path, u64 min_objectid);
528 void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
529 			     struct btrfs_path *path,
530 			     const struct btrfs_key *new_key);
531 struct extent_buffer *btrfs_root_node(struct btrfs_root *root);
532 int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
533 			struct btrfs_key *key, int lowest_level,
534 			u64 min_trans);
535 int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
536 			 struct btrfs_path *path,
537 			 u64 min_trans);
538 struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent,
539 					   int slot);
540 
541 int btrfs_cow_block(struct btrfs_trans_handle *trans,
542 		    struct btrfs_root *root, struct extent_buffer *buf,
543 		    struct extent_buffer *parent, int parent_slot,
544 		    struct extent_buffer **cow_ret,
545 		    enum btrfs_lock_nesting nest);
546 int btrfs_force_cow_block(struct btrfs_trans_handle *trans,
547 			  struct btrfs_root *root,
548 			  struct extent_buffer *buf,
549 			  struct extent_buffer *parent, int parent_slot,
550 			  struct extent_buffer **cow_ret,
551 			  u64 search_start, u64 empty_size,
552 			  enum btrfs_lock_nesting nest);
553 int btrfs_copy_root(struct btrfs_trans_handle *trans,
554 		      struct btrfs_root *root,
555 		      struct extent_buffer *buf,
556 		      struct extent_buffer **cow_ret, u64 new_root_objectid);
557 bool btrfs_block_can_be_shared(struct btrfs_trans_handle *trans,
558 			       struct btrfs_root *root,
559 			       struct extent_buffer *buf);
560 int btrfs_del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
561 		  struct btrfs_path *path, int level, int slot);
562 void btrfs_extend_item(struct btrfs_trans_handle *trans,
563 		       struct btrfs_path *path, u32 data_size);
564 void btrfs_truncate_item(struct btrfs_trans_handle *trans,
565 			 struct btrfs_path *path, u32 new_size, int from_end);
566 int btrfs_split_item(struct btrfs_trans_handle *trans,
567 		     struct btrfs_root *root,
568 		     struct btrfs_path *path,
569 		     const struct btrfs_key *new_key,
570 		     unsigned long split_offset);
571 int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
572 			 struct btrfs_root *root,
573 			 struct btrfs_path *path,
574 			 const struct btrfs_key *new_key);
575 int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path,
576 		u64 inum, u64 ioff, u8 key_type, struct btrfs_key *found_key);
577 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
578 		      const struct btrfs_key *key, struct btrfs_path *p,
579 		      int ins_len, int cow);
580 int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key,
581 			  struct btrfs_path *p, u64 time_seq);
582 int btrfs_search_slot_for_read(struct btrfs_root *root,
583 			       const struct btrfs_key *key,
584 			       struct btrfs_path *p, int find_higher,
585 			       int return_any);
586 void btrfs_release_path(struct btrfs_path *p);
587 struct btrfs_path *btrfs_alloc_path(void);
588 void btrfs_free_path(struct btrfs_path *p);
589 
590 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
591 		   struct btrfs_path *path, int slot, int nr);
592 static inline int btrfs_del_item(struct btrfs_trans_handle *trans,
593 				 struct btrfs_root *root,
594 				 struct btrfs_path *path)
595 {
596 	return btrfs_del_items(trans, root, path, path->slots[0], 1);
597 }
598 
599 /*
600  * Describes a batch of items to insert in a btree. This is used by
601  * btrfs_insert_empty_items().
602  */
603 struct btrfs_item_batch {
604 	/*
605 	 * Pointer to an array containing the keys of the items to insert (in
606 	 * sorted order).
607 	 */
608 	const struct btrfs_key *keys;
609 	/* Pointer to an array containing the data size for each item to insert. */
610 	const u32 *data_sizes;
611 	/*
612 	 * The sum of data sizes for all items. The caller can compute this while
613 	 * setting up the data_sizes array, so it ends up being more efficient
614 	 * than having btrfs_insert_empty_items() or setup_item_for_insert()
615 	 * doing it, as it would avoid an extra loop over a potentially large
616 	 * array, and in the case of setup_item_for_insert(), we would be doing
617 	 * it while holding a write lock on a leaf and often on upper level nodes
618 	 * too, unnecessarily increasing the size of a critical section.
619 	 */
620 	u32 total_data_size;
621 	/* Size of the keys and data_sizes arrays (number of items in the batch). */
622 	int nr;
623 };
624 
625 void btrfs_setup_item_for_insert(struct btrfs_trans_handle *trans,
626 				 struct btrfs_root *root,
627 				 struct btrfs_path *path,
628 				 const struct btrfs_key *key,
629 				 u32 data_size);
630 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
631 		      const struct btrfs_key *key, void *data, u32 data_size);
632 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
633 			     struct btrfs_root *root,
634 			     struct btrfs_path *path,
635 			     const struct btrfs_item_batch *batch);
636 
637 static inline int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
638 					  struct btrfs_root *root,
639 					  struct btrfs_path *path,
640 					  const struct btrfs_key *key,
641 					  u32 data_size)
642 {
643 	struct btrfs_item_batch batch;
644 
645 	batch.keys = key;
646 	batch.data_sizes = &data_size;
647 	batch.total_data_size = data_size;
648 	batch.nr = 1;
649 
650 	return btrfs_insert_empty_items(trans, root, path, &batch);
651 }
652 
653 int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
654 			u64 time_seq);
655 
656 int btrfs_search_backwards(struct btrfs_root *root, struct btrfs_key *key,
657 			   struct btrfs_path *path);
658 
659 int btrfs_get_next_valid_item(struct btrfs_root *root, struct btrfs_key *key,
660 			      struct btrfs_path *path);
661 
662 /*
663  * Search in @root for a given @key, and store the slot found in @found_key.
664  *
665  * @root:	The root node of the tree.
666  * @key:	The key we are looking for.
667  * @found_key:	Will hold the found item.
668  * @path:	Holds the current slot/leaf.
669  * @iter_ret:	Contains the value returned from btrfs_search_slot or
670  * 		btrfs_get_next_valid_item, whichever was executed last.
671  *
672  * The @iter_ret is an output variable that will contain the return value of
673  * btrfs_search_slot, if it encountered an error, or the value returned from
674  * btrfs_get_next_valid_item otherwise. That return value can be 0, if a valid
675  * slot was found, 1 if there were no more leaves, and <0 if there was an error.
676  *
677  * It's recommended to use a separate variable for iter_ret and then use it to
678  * set the function return value so there's no confusion of the 0/1/errno
679  * values stemming from btrfs_search_slot.
680  */
681 #define btrfs_for_each_slot(root, key, found_key, path, iter_ret)		\
682 	for (iter_ret = btrfs_search_slot(NULL, (root), (key), (path), 0, 0);	\
683 		(iter_ret) >= 0 &&						\
684 		(iter_ret = btrfs_get_next_valid_item((root), (found_key), (path))) == 0; \
685 		(path)->slots[0]++						\
686 	)
687 
688 int btrfs_next_old_item(struct btrfs_root *root, struct btrfs_path *path, u64 time_seq);
689 
690 /*
691  * Search the tree again to find a leaf with greater keys.
692  *
693  * Returns 0 if it found something or 1 if there are no greater leaves.
694  * Returns < 0 on error.
695  */
696 static inline int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
697 {
698 	return btrfs_next_old_leaf(root, path, 0);
699 }
700 
701 static inline int btrfs_next_item(struct btrfs_root *root, struct btrfs_path *p)
702 {
703 	return btrfs_next_old_item(root, p, 0);
704 }
705 int btrfs_leaf_free_space(const struct extent_buffer *leaf);
706 
707 static inline int is_fstree(u64 rootid)
708 {
709 	if (rootid == BTRFS_FS_TREE_OBJECTID ||
710 	    ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID &&
711 	      !btrfs_qgroup_level(rootid)))
712 		return 1;
713 	return 0;
714 }
715 
716 static inline bool btrfs_is_data_reloc_root(const struct btrfs_root *root)
717 {
718 	return root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID;
719 }
720 
721 u16 btrfs_csum_type_size(u16 type);
722 int btrfs_super_csum_size(const struct btrfs_super_block *s);
723 const char *btrfs_super_csum_name(u16 csum_type);
724 const char *btrfs_super_csum_driver(u16 csum_type);
725 size_t __attribute_const__ btrfs_get_num_csums(void);
726 
727 /*
728  * We use page status Private2 to indicate there is an ordered extent with
729  * unfinished IO.
730  *
731  * Rename the Private2 accessors to Ordered, to improve readability.
732  */
733 #define PageOrdered(page)		PagePrivate2(page)
734 #define SetPageOrdered(page)		SetPagePrivate2(page)
735 #define ClearPageOrdered(page)		ClearPagePrivate2(page)
736 #define folio_test_ordered(folio)	folio_test_private_2(folio)
737 #define folio_set_ordered(folio)	folio_set_private_2(folio)
738 #define folio_clear_ordered(folio)	folio_clear_private_2(folio)
739 
740 #endif
741