1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2007 Oracle.  All rights reserved.
4  */
5 
6 #include <linux/fs.h>
7 #include <linux/pagemap.h>
8 #include <linux/time.h>
9 #include <linux/init.h>
10 #include <linux/string.h>
11 #include <linux/backing-dev.h>
12 #include <linux/falloc.h>
13 #include <linux/writeback.h>
14 #include <linux/compat.h>
15 #include <linux/slab.h>
16 #include <linux/btrfs.h>
17 #include <linux/uio.h>
18 #include <linux/iversion.h>
19 #include "ctree.h"
20 #include "disk-io.h"
21 #include "transaction.h"
22 #include "btrfs_inode.h"
23 #include "print-tree.h"
24 #include "tree-log.h"
25 #include "locking.h"
26 #include "volumes.h"
27 #include "qgroup.h"
28 #include "compression.h"
29 
30 static struct kmem_cache *btrfs_inode_defrag_cachep;
31 /*
32  * when auto defrag is enabled we
33  * queue up these defrag structs to remember which
34  * inodes need defragging passes
35  */
36 struct inode_defrag {
37 	struct rb_node rb_node;
38 	/* objectid */
39 	u64 ino;
40 	/*
41 	 * transid where the defrag was added, we search for
42 	 * extents newer than this
43 	 */
44 	u64 transid;
45 
46 	/* root objectid */
47 	u64 root;
48 
49 	/* last offset we were able to defrag */
50 	u64 last_offset;
51 
52 	/* if we've wrapped around back to zero once already */
53 	int cycled;
54 };
55 
__compare_inode_defrag(struct inode_defrag * defrag1,struct inode_defrag * defrag2)56 static int __compare_inode_defrag(struct inode_defrag *defrag1,
57 				  struct inode_defrag *defrag2)
58 {
59 	if (defrag1->root > defrag2->root)
60 		return 1;
61 	else if (defrag1->root < defrag2->root)
62 		return -1;
63 	else if (defrag1->ino > defrag2->ino)
64 		return 1;
65 	else if (defrag1->ino < defrag2->ino)
66 		return -1;
67 	else
68 		return 0;
69 }
70 
71 /* pop a record for an inode into the defrag tree.  The lock
72  * must be held already
73  *
74  * If you're inserting a record for an older transid than an
75  * existing record, the transid already in the tree is lowered
76  *
77  * If an existing record is found the defrag item you
78  * pass in is freed
79  */
__btrfs_add_inode_defrag(struct btrfs_inode * inode,struct inode_defrag * defrag)80 static int __btrfs_add_inode_defrag(struct btrfs_inode *inode,
81 				    struct inode_defrag *defrag)
82 {
83 	struct btrfs_fs_info *fs_info = inode->root->fs_info;
84 	struct inode_defrag *entry;
85 	struct rb_node **p;
86 	struct rb_node *parent = NULL;
87 	int ret;
88 
89 	p = &fs_info->defrag_inodes.rb_node;
90 	while (*p) {
91 		parent = *p;
92 		entry = rb_entry(parent, struct inode_defrag, rb_node);
93 
94 		ret = __compare_inode_defrag(defrag, entry);
95 		if (ret < 0)
96 			p = &parent->rb_left;
97 		else if (ret > 0)
98 			p = &parent->rb_right;
99 		else {
100 			/* if we're reinserting an entry for
101 			 * an old defrag run, make sure to
102 			 * lower the transid of our existing record
103 			 */
104 			if (defrag->transid < entry->transid)
105 				entry->transid = defrag->transid;
106 			if (defrag->last_offset > entry->last_offset)
107 				entry->last_offset = defrag->last_offset;
108 			return -EEXIST;
109 		}
110 	}
111 	set_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags);
112 	rb_link_node(&defrag->rb_node, parent, p);
113 	rb_insert_color(&defrag->rb_node, &fs_info->defrag_inodes);
114 	return 0;
115 }
116 
__need_auto_defrag(struct btrfs_fs_info * fs_info)117 static inline int __need_auto_defrag(struct btrfs_fs_info *fs_info)
118 {
119 	if (!btrfs_test_opt(fs_info, AUTO_DEFRAG))
120 		return 0;
121 
122 	if (btrfs_fs_closing(fs_info))
123 		return 0;
124 
125 	return 1;
126 }
127 
128 /*
129  * insert a defrag record for this inode if auto defrag is
130  * enabled
131  */
btrfs_add_inode_defrag(struct btrfs_trans_handle * trans,struct btrfs_inode * inode)132 int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
133 			   struct btrfs_inode *inode)
134 {
135 	struct btrfs_root *root = inode->root;
136 	struct btrfs_fs_info *fs_info = root->fs_info;
137 	struct inode_defrag *defrag;
138 	u64 transid;
139 	int ret;
140 
141 	if (!__need_auto_defrag(fs_info))
142 		return 0;
143 
144 	if (test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags))
145 		return 0;
146 
147 	if (trans)
148 		transid = trans->transid;
149 	else
150 		transid = inode->root->last_trans;
151 
152 	defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS);
153 	if (!defrag)
154 		return -ENOMEM;
155 
156 	defrag->ino = btrfs_ino(inode);
157 	defrag->transid = transid;
158 	defrag->root = root->root_key.objectid;
159 
160 	spin_lock(&fs_info->defrag_inodes_lock);
161 	if (!test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags)) {
162 		/*
163 		 * If we set IN_DEFRAG flag and evict the inode from memory,
164 		 * and then re-read this inode, this new inode doesn't have
165 		 * IN_DEFRAG flag. At the case, we may find the existed defrag.
166 		 */
167 		ret = __btrfs_add_inode_defrag(inode, defrag);
168 		if (ret)
169 			kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
170 	} else {
171 		kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
172 	}
173 	spin_unlock(&fs_info->defrag_inodes_lock);
174 	return 0;
175 }
176 
177 /*
178  * Requeue the defrag object. If there is a defrag object that points to
179  * the same inode in the tree, we will merge them together (by
180  * __btrfs_add_inode_defrag()) and free the one that we want to requeue.
181  */
btrfs_requeue_inode_defrag(struct btrfs_inode * inode,struct inode_defrag * defrag)182 static void btrfs_requeue_inode_defrag(struct btrfs_inode *inode,
183 				       struct inode_defrag *defrag)
184 {
185 	struct btrfs_fs_info *fs_info = inode->root->fs_info;
186 	int ret;
187 
188 	if (!__need_auto_defrag(fs_info))
189 		goto out;
190 
191 	/*
192 	 * Here we don't check the IN_DEFRAG flag, because we need merge
193 	 * them together.
194 	 */
195 	spin_lock(&fs_info->defrag_inodes_lock);
196 	ret = __btrfs_add_inode_defrag(inode, defrag);
197 	spin_unlock(&fs_info->defrag_inodes_lock);
198 	if (ret)
199 		goto out;
200 	return;
201 out:
202 	kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
203 }
204 
205 /*
206  * pick the defragable inode that we want, if it doesn't exist, we will get
207  * the next one.
208  */
209 static struct inode_defrag *
btrfs_pick_defrag_inode(struct btrfs_fs_info * fs_info,u64 root,u64 ino)210 btrfs_pick_defrag_inode(struct btrfs_fs_info *fs_info, u64 root, u64 ino)
211 {
212 	struct inode_defrag *entry = NULL;
213 	struct inode_defrag tmp;
214 	struct rb_node *p;
215 	struct rb_node *parent = NULL;
216 	int ret;
217 
218 	tmp.ino = ino;
219 	tmp.root = root;
220 
221 	spin_lock(&fs_info->defrag_inodes_lock);
222 	p = fs_info->defrag_inodes.rb_node;
223 	while (p) {
224 		parent = p;
225 		entry = rb_entry(parent, struct inode_defrag, rb_node);
226 
227 		ret = __compare_inode_defrag(&tmp, entry);
228 		if (ret < 0)
229 			p = parent->rb_left;
230 		else if (ret > 0)
231 			p = parent->rb_right;
232 		else
233 			goto out;
234 	}
235 
236 	if (parent && __compare_inode_defrag(&tmp, entry) > 0) {
237 		parent = rb_next(parent);
238 		if (parent)
239 			entry = rb_entry(parent, struct inode_defrag, rb_node);
240 		else
241 			entry = NULL;
242 	}
243 out:
244 	if (entry)
245 		rb_erase(parent, &fs_info->defrag_inodes);
246 	spin_unlock(&fs_info->defrag_inodes_lock);
247 	return entry;
248 }
249 
btrfs_cleanup_defrag_inodes(struct btrfs_fs_info * fs_info)250 void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info)
251 {
252 	struct inode_defrag *defrag;
253 	struct rb_node *node;
254 
255 	spin_lock(&fs_info->defrag_inodes_lock);
256 	node = rb_first(&fs_info->defrag_inodes);
257 	while (node) {
258 		rb_erase(node, &fs_info->defrag_inodes);
259 		defrag = rb_entry(node, struct inode_defrag, rb_node);
260 		kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
261 
262 		cond_resched_lock(&fs_info->defrag_inodes_lock);
263 
264 		node = rb_first(&fs_info->defrag_inodes);
265 	}
266 	spin_unlock(&fs_info->defrag_inodes_lock);
267 }
268 
269 #define BTRFS_DEFRAG_BATCH	1024
270 
__btrfs_run_defrag_inode(struct btrfs_fs_info * fs_info,struct inode_defrag * defrag)271 static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
272 				    struct inode_defrag *defrag)
273 {
274 	struct btrfs_root *inode_root;
275 	struct inode *inode;
276 	struct btrfs_key key;
277 	struct btrfs_ioctl_defrag_range_args range;
278 	int num_defrag;
279 	int index;
280 	int ret;
281 
282 	/* get the inode */
283 	key.objectid = defrag->root;
284 	key.type = BTRFS_ROOT_ITEM_KEY;
285 	key.offset = (u64)-1;
286 
287 	index = srcu_read_lock(&fs_info->subvol_srcu);
288 
289 	inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
290 	if (IS_ERR(inode_root)) {
291 		ret = PTR_ERR(inode_root);
292 		goto cleanup;
293 	}
294 
295 	key.objectid = defrag->ino;
296 	key.type = BTRFS_INODE_ITEM_KEY;
297 	key.offset = 0;
298 	inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
299 	if (IS_ERR(inode)) {
300 		ret = PTR_ERR(inode);
301 		goto cleanup;
302 	}
303 	srcu_read_unlock(&fs_info->subvol_srcu, index);
304 
305 	/* do a chunk of defrag */
306 	clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
307 	memset(&range, 0, sizeof(range));
308 	range.len = (u64)-1;
309 	range.start = defrag->last_offset;
310 
311 	sb_start_write(fs_info->sb);
312 	num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
313 				       BTRFS_DEFRAG_BATCH);
314 	sb_end_write(fs_info->sb);
315 	/*
316 	 * if we filled the whole defrag batch, there
317 	 * must be more work to do.  Queue this defrag
318 	 * again
319 	 */
320 	if (num_defrag == BTRFS_DEFRAG_BATCH) {
321 		defrag->last_offset = range.start;
322 		btrfs_requeue_inode_defrag(BTRFS_I(inode), defrag);
323 	} else if (defrag->last_offset && !defrag->cycled) {
324 		/*
325 		 * we didn't fill our defrag batch, but
326 		 * we didn't start at zero.  Make sure we loop
327 		 * around to the start of the file.
328 		 */
329 		defrag->last_offset = 0;
330 		defrag->cycled = 1;
331 		btrfs_requeue_inode_defrag(BTRFS_I(inode), defrag);
332 	} else {
333 		kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
334 	}
335 
336 	iput(inode);
337 	return 0;
338 cleanup:
339 	srcu_read_unlock(&fs_info->subvol_srcu, index);
340 	kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
341 	return ret;
342 }
343 
344 /*
345  * run through the list of inodes in the FS that need
346  * defragging
347  */
btrfs_run_defrag_inodes(struct btrfs_fs_info * fs_info)348 int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
349 {
350 	struct inode_defrag *defrag;
351 	u64 first_ino = 0;
352 	u64 root_objectid = 0;
353 
354 	atomic_inc(&fs_info->defrag_running);
355 	while (1) {
356 		/* Pause the auto defragger. */
357 		if (test_bit(BTRFS_FS_STATE_REMOUNTING,
358 			     &fs_info->fs_state))
359 			break;
360 
361 		if (!__need_auto_defrag(fs_info))
362 			break;
363 
364 		/* find an inode to defrag */
365 		defrag = btrfs_pick_defrag_inode(fs_info, root_objectid,
366 						 first_ino);
367 		if (!defrag) {
368 			if (root_objectid || first_ino) {
369 				root_objectid = 0;
370 				first_ino = 0;
371 				continue;
372 			} else {
373 				break;
374 			}
375 		}
376 
377 		first_ino = defrag->ino + 1;
378 		root_objectid = defrag->root;
379 
380 		__btrfs_run_defrag_inode(fs_info, defrag);
381 	}
382 	atomic_dec(&fs_info->defrag_running);
383 
384 	/*
385 	 * during unmount, we use the transaction_wait queue to
386 	 * wait for the defragger to stop
387 	 */
388 	wake_up(&fs_info->transaction_wait);
389 	return 0;
390 }
391 
392 /* simple helper to fault in pages and copy.  This should go away
393  * and be replaced with calls into generic code.
394  */
btrfs_copy_from_user(loff_t pos,size_t write_bytes,struct page ** prepared_pages,struct iov_iter * i)395 static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes,
396 					 struct page **prepared_pages,
397 					 struct iov_iter *i)
398 {
399 	size_t copied = 0;
400 	size_t total_copied = 0;
401 	int pg = 0;
402 	int offset = pos & (PAGE_SIZE - 1);
403 
404 	while (write_bytes > 0) {
405 		size_t count = min_t(size_t,
406 				     PAGE_SIZE - offset, write_bytes);
407 		struct page *page = prepared_pages[pg];
408 		/*
409 		 * Copy data from userspace to the current page
410 		 */
411 		copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
412 
413 		/* Flush processor's dcache for this page */
414 		flush_dcache_page(page);
415 
416 		/*
417 		 * if we get a partial write, we can end up with
418 		 * partially up to date pages.  These add
419 		 * a lot of complexity, so make sure they don't
420 		 * happen by forcing this copy to be retried.
421 		 *
422 		 * The rest of the btrfs_file_write code will fall
423 		 * back to page at a time copies after we return 0.
424 		 */
425 		if (!PageUptodate(page) && copied < count)
426 			copied = 0;
427 
428 		iov_iter_advance(i, copied);
429 		write_bytes -= copied;
430 		total_copied += copied;
431 
432 		/* Return to btrfs_file_write_iter to fault page */
433 		if (unlikely(copied == 0))
434 			break;
435 
436 		if (copied < PAGE_SIZE - offset) {
437 			offset += copied;
438 		} else {
439 			pg++;
440 			offset = 0;
441 		}
442 	}
443 	return total_copied;
444 }
445 
446 /*
447  * unlocks pages after btrfs_file_write is done with them
448  */
btrfs_drop_pages(struct page ** pages,size_t num_pages)449 static void btrfs_drop_pages(struct page **pages, size_t num_pages)
450 {
451 	size_t i;
452 	for (i = 0; i < num_pages; i++) {
453 		/* page checked is some magic around finding pages that
454 		 * have been modified without going through btrfs_set_page_dirty
455 		 * clear it here. There should be no need to mark the pages
456 		 * accessed as prepare_pages should have marked them accessed
457 		 * in prepare_pages via find_or_create_page()
458 		 */
459 		ClearPageChecked(pages[i]);
460 		unlock_page(pages[i]);
461 		put_page(pages[i]);
462 	}
463 }
464 
btrfs_find_new_delalloc_bytes(struct btrfs_inode * inode,const u64 start,const u64 len,struct extent_state ** cached_state)465 static int btrfs_find_new_delalloc_bytes(struct btrfs_inode *inode,
466 					 const u64 start,
467 					 const u64 len,
468 					 struct extent_state **cached_state)
469 {
470 	u64 search_start = start;
471 	const u64 end = start + len - 1;
472 
473 	while (search_start < end) {
474 		const u64 search_len = end - search_start + 1;
475 		struct extent_map *em;
476 		u64 em_len;
477 		int ret = 0;
478 
479 		em = btrfs_get_extent(inode, NULL, 0, search_start,
480 				      search_len, 0);
481 		if (IS_ERR(em))
482 			return PTR_ERR(em);
483 
484 		if (em->block_start != EXTENT_MAP_HOLE)
485 			goto next;
486 
487 		em_len = em->len;
488 		if (em->start < search_start)
489 			em_len -= search_start - em->start;
490 		if (em_len > search_len)
491 			em_len = search_len;
492 
493 		ret = set_extent_bit(&inode->io_tree, search_start,
494 				     search_start + em_len - 1,
495 				     EXTENT_DELALLOC_NEW,
496 				     NULL, cached_state, GFP_NOFS);
497 next:
498 		search_start = extent_map_end(em);
499 		free_extent_map(em);
500 		if (ret)
501 			return ret;
502 	}
503 	return 0;
504 }
505 
506 /*
507  * after copy_from_user, pages need to be dirtied and we need to make
508  * sure holes are created between the current EOF and the start of
509  * any next extents (if required).
510  *
511  * this also makes the decision about creating an inline extent vs
512  * doing real data extents, marking pages dirty and delalloc as required.
513  */
btrfs_dirty_pages(struct inode * inode,struct page ** pages,size_t num_pages,loff_t pos,size_t write_bytes,struct extent_state ** cached)514 int btrfs_dirty_pages(struct inode *inode, struct page **pages,
515 		      size_t num_pages, loff_t pos, size_t write_bytes,
516 		      struct extent_state **cached)
517 {
518 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
519 	int err = 0;
520 	int i;
521 	u64 num_bytes;
522 	u64 start_pos;
523 	u64 end_of_last_block;
524 	u64 end_pos = pos + write_bytes;
525 	loff_t isize = i_size_read(inode);
526 	unsigned int extra_bits = 0;
527 
528 	start_pos = pos & ~((u64) fs_info->sectorsize - 1);
529 	num_bytes = round_up(write_bytes + pos - start_pos,
530 			     fs_info->sectorsize);
531 
532 	end_of_last_block = start_pos + num_bytes - 1;
533 
534 	/*
535 	 * The pages may have already been dirty, clear out old accounting so
536 	 * we can set things up properly
537 	 */
538 	clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos, end_of_last_block,
539 			 EXTENT_DIRTY | EXTENT_DELALLOC |
540 			 EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 0, 0, cached);
541 
542 	if (!btrfs_is_free_space_inode(BTRFS_I(inode))) {
543 		if (start_pos >= isize &&
544 		    !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC)) {
545 			/*
546 			 * There can't be any extents following eof in this case
547 			 * so just set the delalloc new bit for the range
548 			 * directly.
549 			 */
550 			extra_bits |= EXTENT_DELALLOC_NEW;
551 		} else {
552 			err = btrfs_find_new_delalloc_bytes(BTRFS_I(inode),
553 							    start_pos,
554 							    num_bytes, cached);
555 			if (err)
556 				return err;
557 		}
558 	}
559 
560 	err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
561 					extra_bits, cached, 0);
562 	if (err)
563 		return err;
564 
565 	for (i = 0; i < num_pages; i++) {
566 		struct page *p = pages[i];
567 		SetPageUptodate(p);
568 		ClearPageChecked(p);
569 		set_page_dirty(p);
570 	}
571 
572 	/*
573 	 * we've only changed i_size in ram, and we haven't updated
574 	 * the disk i_size.  There is no need to log the inode
575 	 * at this time.
576 	 */
577 	if (end_pos > isize)
578 		i_size_write(inode, end_pos);
579 	return 0;
580 }
581 
582 /*
583  * this drops all the extents in the cache that intersect the range
584  * [start, end].  Existing extents are split as required.
585  */
btrfs_drop_extent_cache(struct btrfs_inode * inode,u64 start,u64 end,int skip_pinned)586 void btrfs_drop_extent_cache(struct btrfs_inode *inode, u64 start, u64 end,
587 			     int skip_pinned)
588 {
589 	struct extent_map *em;
590 	struct extent_map *split = NULL;
591 	struct extent_map *split2 = NULL;
592 	struct extent_map_tree *em_tree = &inode->extent_tree;
593 	u64 len = end - start + 1;
594 	u64 gen;
595 	int ret;
596 	int testend = 1;
597 	unsigned long flags;
598 	int compressed = 0;
599 	bool modified;
600 
601 	WARN_ON(end < start);
602 	if (end == (u64)-1) {
603 		len = (u64)-1;
604 		testend = 0;
605 	}
606 	while (1) {
607 		int no_splits = 0;
608 
609 		modified = false;
610 		if (!split)
611 			split = alloc_extent_map();
612 		if (!split2)
613 			split2 = alloc_extent_map();
614 		if (!split || !split2)
615 			no_splits = 1;
616 
617 		write_lock(&em_tree->lock);
618 		em = lookup_extent_mapping(em_tree, start, len);
619 		if (!em) {
620 			write_unlock(&em_tree->lock);
621 			break;
622 		}
623 		flags = em->flags;
624 		gen = em->generation;
625 		if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
626 			if (testend && em->start + em->len >= start + len) {
627 				free_extent_map(em);
628 				write_unlock(&em_tree->lock);
629 				break;
630 			}
631 			start = em->start + em->len;
632 			if (testend)
633 				len = start + len - (em->start + em->len);
634 			free_extent_map(em);
635 			write_unlock(&em_tree->lock);
636 			continue;
637 		}
638 		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
639 		clear_bit(EXTENT_FLAG_PINNED, &em->flags);
640 		clear_bit(EXTENT_FLAG_LOGGING, &flags);
641 		modified = !list_empty(&em->list);
642 		if (no_splits)
643 			goto next;
644 
645 		if (em->start < start) {
646 			split->start = em->start;
647 			split->len = start - em->start;
648 
649 			if (em->block_start < EXTENT_MAP_LAST_BYTE) {
650 				split->orig_start = em->orig_start;
651 				split->block_start = em->block_start;
652 
653 				if (compressed)
654 					split->block_len = em->block_len;
655 				else
656 					split->block_len = split->len;
657 				split->orig_block_len = max(split->block_len,
658 						em->orig_block_len);
659 				split->ram_bytes = em->ram_bytes;
660 			} else {
661 				split->orig_start = split->start;
662 				split->block_len = 0;
663 				split->block_start = em->block_start;
664 				split->orig_block_len = 0;
665 				split->ram_bytes = split->len;
666 			}
667 
668 			split->generation = gen;
669 			split->bdev = em->bdev;
670 			split->flags = flags;
671 			split->compress_type = em->compress_type;
672 			replace_extent_mapping(em_tree, em, split, modified);
673 			free_extent_map(split);
674 			split = split2;
675 			split2 = NULL;
676 		}
677 		if (testend && em->start + em->len > start + len) {
678 			u64 diff = start + len - em->start;
679 
680 			split->start = start + len;
681 			split->len = em->start + em->len - (start + len);
682 			split->bdev = em->bdev;
683 			split->flags = flags;
684 			split->compress_type = em->compress_type;
685 			split->generation = gen;
686 
687 			if (em->block_start < EXTENT_MAP_LAST_BYTE) {
688 				split->orig_block_len = max(em->block_len,
689 						    em->orig_block_len);
690 
691 				split->ram_bytes = em->ram_bytes;
692 				if (compressed) {
693 					split->block_len = em->block_len;
694 					split->block_start = em->block_start;
695 					split->orig_start = em->orig_start;
696 				} else {
697 					split->block_len = split->len;
698 					split->block_start = em->block_start
699 						+ diff;
700 					split->orig_start = em->orig_start;
701 				}
702 			} else {
703 				split->ram_bytes = split->len;
704 				split->orig_start = split->start;
705 				split->block_len = 0;
706 				split->block_start = em->block_start;
707 				split->orig_block_len = 0;
708 			}
709 
710 			if (extent_map_in_tree(em)) {
711 				replace_extent_mapping(em_tree, em, split,
712 						       modified);
713 			} else {
714 				ret = add_extent_mapping(em_tree, split,
715 							 modified);
716 				ASSERT(ret == 0); /* Logic error */
717 			}
718 			free_extent_map(split);
719 			split = NULL;
720 		}
721 next:
722 		if (extent_map_in_tree(em))
723 			remove_extent_mapping(em_tree, em);
724 		write_unlock(&em_tree->lock);
725 
726 		/* once for us */
727 		free_extent_map(em);
728 		/* once for the tree*/
729 		free_extent_map(em);
730 	}
731 	if (split)
732 		free_extent_map(split);
733 	if (split2)
734 		free_extent_map(split2);
735 }
736 
737 /*
738  * this is very complex, but the basic idea is to drop all extents
739  * in the range start - end.  hint_block is filled in with a block number
740  * that would be a good hint to the block allocator for this file.
741  *
742  * If an extent intersects the range but is not entirely inside the range
743  * it is either truncated or split.  Anything entirely inside the range
744  * is deleted from the tree.
745  */
__btrfs_drop_extents(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct inode * inode,struct btrfs_path * path,u64 start,u64 end,u64 * drop_end,int drop_cache,int replace_extent,u32 extent_item_size,int * key_inserted)746 int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
747 			 struct btrfs_root *root, struct inode *inode,
748 			 struct btrfs_path *path, u64 start, u64 end,
749 			 u64 *drop_end, int drop_cache,
750 			 int replace_extent,
751 			 u32 extent_item_size,
752 			 int *key_inserted)
753 {
754 	struct btrfs_fs_info *fs_info = root->fs_info;
755 	struct extent_buffer *leaf;
756 	struct btrfs_file_extent_item *fi;
757 	struct btrfs_key key;
758 	struct btrfs_key new_key;
759 	u64 ino = btrfs_ino(BTRFS_I(inode));
760 	u64 search_start = start;
761 	u64 disk_bytenr = 0;
762 	u64 num_bytes = 0;
763 	u64 extent_offset = 0;
764 	u64 extent_end = 0;
765 	u64 last_end = start;
766 	int del_nr = 0;
767 	int del_slot = 0;
768 	int extent_type;
769 	int recow;
770 	int ret;
771 	int modify_tree = -1;
772 	int update_refs;
773 	int found = 0;
774 	int leafs_visited = 0;
775 
776 	if (drop_cache)
777 		btrfs_drop_extent_cache(BTRFS_I(inode), start, end - 1, 0);
778 
779 	if (start >= BTRFS_I(inode)->disk_i_size && !replace_extent)
780 		modify_tree = 0;
781 
782 	update_refs = (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
783 		       root == fs_info->tree_root);
784 	while (1) {
785 		recow = 0;
786 		ret = btrfs_lookup_file_extent(trans, root, path, ino,
787 					       search_start, modify_tree);
788 		if (ret < 0)
789 			break;
790 		if (ret > 0 && path->slots[0] > 0 && search_start == start) {
791 			leaf = path->nodes[0];
792 			btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
793 			if (key.objectid == ino &&
794 			    key.type == BTRFS_EXTENT_DATA_KEY)
795 				path->slots[0]--;
796 		}
797 		ret = 0;
798 		leafs_visited++;
799 next_slot:
800 		leaf = path->nodes[0];
801 		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
802 			BUG_ON(del_nr > 0);
803 			ret = btrfs_next_leaf(root, path);
804 			if (ret < 0)
805 				break;
806 			if (ret > 0) {
807 				ret = 0;
808 				break;
809 			}
810 			leafs_visited++;
811 			leaf = path->nodes[0];
812 			recow = 1;
813 		}
814 
815 		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
816 
817 		if (key.objectid > ino)
818 			break;
819 		if (WARN_ON_ONCE(key.objectid < ino) ||
820 		    key.type < BTRFS_EXTENT_DATA_KEY) {
821 			ASSERT(del_nr == 0);
822 			path->slots[0]++;
823 			goto next_slot;
824 		}
825 		if (key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
826 			break;
827 
828 		fi = btrfs_item_ptr(leaf, path->slots[0],
829 				    struct btrfs_file_extent_item);
830 		extent_type = btrfs_file_extent_type(leaf, fi);
831 
832 		if (extent_type == BTRFS_FILE_EXTENT_REG ||
833 		    extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
834 			disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
835 			num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
836 			extent_offset = btrfs_file_extent_offset(leaf, fi);
837 			extent_end = key.offset +
838 				btrfs_file_extent_num_bytes(leaf, fi);
839 		} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
840 			extent_end = key.offset +
841 				btrfs_file_extent_ram_bytes(leaf, fi);
842 		} else {
843 			/* can't happen */
844 			BUG();
845 		}
846 
847 		/*
848 		 * Don't skip extent items representing 0 byte lengths. They
849 		 * used to be created (bug) if while punching holes we hit
850 		 * -ENOSPC condition. So if we find one here, just ensure we
851 		 * delete it, otherwise we would insert a new file extent item
852 		 * with the same key (offset) as that 0 bytes length file
853 		 * extent item in the call to setup_items_for_insert() later
854 		 * in this function.
855 		 */
856 		if (extent_end == key.offset && extent_end >= search_start) {
857 			last_end = extent_end;
858 			goto delete_extent_item;
859 		}
860 
861 		if (extent_end <= search_start) {
862 			path->slots[0]++;
863 			goto next_slot;
864 		}
865 
866 		found = 1;
867 		search_start = max(key.offset, start);
868 		if (recow || !modify_tree) {
869 			modify_tree = -1;
870 			btrfs_release_path(path);
871 			continue;
872 		}
873 
874 		/*
875 		 *     | - range to drop - |
876 		 *  | -------- extent -------- |
877 		 */
878 		if (start > key.offset && end < extent_end) {
879 			BUG_ON(del_nr > 0);
880 			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
881 				ret = -EOPNOTSUPP;
882 				break;
883 			}
884 
885 			memcpy(&new_key, &key, sizeof(new_key));
886 			new_key.offset = start;
887 			ret = btrfs_duplicate_item(trans, root, path,
888 						   &new_key);
889 			if (ret == -EAGAIN) {
890 				btrfs_release_path(path);
891 				continue;
892 			}
893 			if (ret < 0)
894 				break;
895 
896 			leaf = path->nodes[0];
897 			fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
898 					    struct btrfs_file_extent_item);
899 			btrfs_set_file_extent_num_bytes(leaf, fi,
900 							start - key.offset);
901 
902 			fi = btrfs_item_ptr(leaf, path->slots[0],
903 					    struct btrfs_file_extent_item);
904 
905 			extent_offset += start - key.offset;
906 			btrfs_set_file_extent_offset(leaf, fi, extent_offset);
907 			btrfs_set_file_extent_num_bytes(leaf, fi,
908 							extent_end - start);
909 			btrfs_mark_buffer_dirty(leaf);
910 
911 			if (update_refs && disk_bytenr > 0) {
912 				ret = btrfs_inc_extent_ref(trans, root,
913 						disk_bytenr, num_bytes, 0,
914 						root->root_key.objectid,
915 						new_key.objectid,
916 						start - extent_offset);
917 				BUG_ON(ret); /* -ENOMEM */
918 			}
919 			key.offset = start;
920 		}
921 		/*
922 		 * From here on out we will have actually dropped something, so
923 		 * last_end can be updated.
924 		 */
925 		last_end = extent_end;
926 
927 		/*
928 		 *  | ---- range to drop ----- |
929 		 *      | -------- extent -------- |
930 		 */
931 		if (start <= key.offset && end < extent_end) {
932 			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
933 				ret = -EOPNOTSUPP;
934 				break;
935 			}
936 
937 			memcpy(&new_key, &key, sizeof(new_key));
938 			new_key.offset = end;
939 			btrfs_set_item_key_safe(fs_info, path, &new_key);
940 
941 			extent_offset += end - key.offset;
942 			btrfs_set_file_extent_offset(leaf, fi, extent_offset);
943 			btrfs_set_file_extent_num_bytes(leaf, fi,
944 							extent_end - end);
945 			btrfs_mark_buffer_dirty(leaf);
946 			if (update_refs && disk_bytenr > 0)
947 				inode_sub_bytes(inode, end - key.offset);
948 			break;
949 		}
950 
951 		search_start = extent_end;
952 		/*
953 		 *       | ---- range to drop ----- |
954 		 *  | -------- extent -------- |
955 		 */
956 		if (start > key.offset && end >= extent_end) {
957 			BUG_ON(del_nr > 0);
958 			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
959 				ret = -EOPNOTSUPP;
960 				break;
961 			}
962 
963 			btrfs_set_file_extent_num_bytes(leaf, fi,
964 							start - key.offset);
965 			btrfs_mark_buffer_dirty(leaf);
966 			if (update_refs && disk_bytenr > 0)
967 				inode_sub_bytes(inode, extent_end - start);
968 			if (end == extent_end)
969 				break;
970 
971 			path->slots[0]++;
972 			goto next_slot;
973 		}
974 
975 		/*
976 		 *  | ---- range to drop ----- |
977 		 *    | ------ extent ------ |
978 		 */
979 		if (start <= key.offset && end >= extent_end) {
980 delete_extent_item:
981 			if (del_nr == 0) {
982 				del_slot = path->slots[0];
983 				del_nr = 1;
984 			} else {
985 				BUG_ON(del_slot + del_nr != path->slots[0]);
986 				del_nr++;
987 			}
988 
989 			if (update_refs &&
990 			    extent_type == BTRFS_FILE_EXTENT_INLINE) {
991 				inode_sub_bytes(inode,
992 						extent_end - key.offset);
993 				extent_end = ALIGN(extent_end,
994 						   fs_info->sectorsize);
995 			} else if (update_refs && disk_bytenr > 0) {
996 				ret = btrfs_free_extent(trans, root,
997 						disk_bytenr, num_bytes, 0,
998 						root->root_key.objectid,
999 						key.objectid, key.offset -
1000 						extent_offset);
1001 				BUG_ON(ret); /* -ENOMEM */
1002 				inode_sub_bytes(inode,
1003 						extent_end - key.offset);
1004 			}
1005 
1006 			if (end == extent_end)
1007 				break;
1008 
1009 			if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
1010 				path->slots[0]++;
1011 				goto next_slot;
1012 			}
1013 
1014 			ret = btrfs_del_items(trans, root, path, del_slot,
1015 					      del_nr);
1016 			if (ret) {
1017 				btrfs_abort_transaction(trans, ret);
1018 				break;
1019 			}
1020 
1021 			del_nr = 0;
1022 			del_slot = 0;
1023 
1024 			btrfs_release_path(path);
1025 			continue;
1026 		}
1027 
1028 		BUG_ON(1);
1029 	}
1030 
1031 	if (!ret && del_nr > 0) {
1032 		/*
1033 		 * Set path->slots[0] to first slot, so that after the delete
1034 		 * if items are move off from our leaf to its immediate left or
1035 		 * right neighbor leafs, we end up with a correct and adjusted
1036 		 * path->slots[0] for our insertion (if replace_extent != 0).
1037 		 */
1038 		path->slots[0] = del_slot;
1039 		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1040 		if (ret)
1041 			btrfs_abort_transaction(trans, ret);
1042 	}
1043 
1044 	leaf = path->nodes[0];
1045 	/*
1046 	 * If btrfs_del_items() was called, it might have deleted a leaf, in
1047 	 * which case it unlocked our path, so check path->locks[0] matches a
1048 	 * write lock.
1049 	 */
1050 	if (!ret && replace_extent && leafs_visited == 1 &&
1051 	    (path->locks[0] == BTRFS_WRITE_LOCK_BLOCKING ||
1052 	     path->locks[0] == BTRFS_WRITE_LOCK) &&
1053 	    btrfs_leaf_free_space(fs_info, leaf) >=
1054 	    sizeof(struct btrfs_item) + extent_item_size) {
1055 
1056 		key.objectid = ino;
1057 		key.type = BTRFS_EXTENT_DATA_KEY;
1058 		key.offset = start;
1059 		if (!del_nr && path->slots[0] < btrfs_header_nritems(leaf)) {
1060 			struct btrfs_key slot_key;
1061 
1062 			btrfs_item_key_to_cpu(leaf, &slot_key, path->slots[0]);
1063 			if (btrfs_comp_cpu_keys(&key, &slot_key) > 0)
1064 				path->slots[0]++;
1065 		}
1066 		setup_items_for_insert(root, path, &key,
1067 				       &extent_item_size,
1068 				       extent_item_size,
1069 				       sizeof(struct btrfs_item) +
1070 				       extent_item_size, 1);
1071 		*key_inserted = 1;
1072 	}
1073 
1074 	if (!replace_extent || !(*key_inserted))
1075 		btrfs_release_path(path);
1076 	if (drop_end)
1077 		*drop_end = found ? min(end, last_end) : end;
1078 	return ret;
1079 }
1080 
btrfs_drop_extents(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct inode * inode,u64 start,u64 end,int drop_cache)1081 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
1082 		       struct btrfs_root *root, struct inode *inode, u64 start,
1083 		       u64 end, int drop_cache)
1084 {
1085 	struct btrfs_path *path;
1086 	int ret;
1087 
1088 	path = btrfs_alloc_path();
1089 	if (!path)
1090 		return -ENOMEM;
1091 	ret = __btrfs_drop_extents(trans, root, inode, path, start, end, NULL,
1092 				   drop_cache, 0, 0, NULL);
1093 	btrfs_free_path(path);
1094 	return ret;
1095 }
1096 
extent_mergeable(struct extent_buffer * leaf,int slot,u64 objectid,u64 bytenr,u64 orig_offset,u64 * start,u64 * end)1097 static int extent_mergeable(struct extent_buffer *leaf, int slot,
1098 			    u64 objectid, u64 bytenr, u64 orig_offset,
1099 			    u64 *start, u64 *end)
1100 {
1101 	struct btrfs_file_extent_item *fi;
1102 	struct btrfs_key key;
1103 	u64 extent_end;
1104 
1105 	if (slot < 0 || slot >= btrfs_header_nritems(leaf))
1106 		return 0;
1107 
1108 	btrfs_item_key_to_cpu(leaf, &key, slot);
1109 	if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
1110 		return 0;
1111 
1112 	fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
1113 	if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
1114 	    btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
1115 	    btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
1116 	    btrfs_file_extent_compression(leaf, fi) ||
1117 	    btrfs_file_extent_encryption(leaf, fi) ||
1118 	    btrfs_file_extent_other_encoding(leaf, fi))
1119 		return 0;
1120 
1121 	extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1122 	if ((*start && *start != key.offset) || (*end && *end != extent_end))
1123 		return 0;
1124 
1125 	*start = key.offset;
1126 	*end = extent_end;
1127 	return 1;
1128 }
1129 
1130 /*
1131  * Mark extent in the range start - end as written.
1132  *
1133  * This changes extent type from 'pre-allocated' to 'regular'. If only
1134  * part of extent is marked as written, the extent will be split into
1135  * two or three.
1136  */
btrfs_mark_extent_written(struct btrfs_trans_handle * trans,struct btrfs_inode * inode,u64 start,u64 end)1137 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
1138 			      struct btrfs_inode *inode, u64 start, u64 end)
1139 {
1140 	struct btrfs_fs_info *fs_info = trans->fs_info;
1141 	struct btrfs_root *root = inode->root;
1142 	struct extent_buffer *leaf;
1143 	struct btrfs_path *path;
1144 	struct btrfs_file_extent_item *fi;
1145 	struct btrfs_key key;
1146 	struct btrfs_key new_key;
1147 	u64 bytenr;
1148 	u64 num_bytes;
1149 	u64 extent_end;
1150 	u64 orig_offset;
1151 	u64 other_start;
1152 	u64 other_end;
1153 	u64 split;
1154 	int del_nr = 0;
1155 	int del_slot = 0;
1156 	int recow;
1157 	int ret = 0;
1158 	u64 ino = btrfs_ino(inode);
1159 
1160 	path = btrfs_alloc_path();
1161 	if (!path)
1162 		return -ENOMEM;
1163 again:
1164 	recow = 0;
1165 	split = start;
1166 	key.objectid = ino;
1167 	key.type = BTRFS_EXTENT_DATA_KEY;
1168 	key.offset = split;
1169 
1170 	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1171 	if (ret < 0)
1172 		goto out;
1173 	if (ret > 0 && path->slots[0] > 0)
1174 		path->slots[0]--;
1175 
1176 	leaf = path->nodes[0];
1177 	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1178 	if (key.objectid != ino ||
1179 	    key.type != BTRFS_EXTENT_DATA_KEY) {
1180 		ret = -EINVAL;
1181 		btrfs_abort_transaction(trans, ret);
1182 		goto out;
1183 	}
1184 	fi = btrfs_item_ptr(leaf, path->slots[0],
1185 			    struct btrfs_file_extent_item);
1186 	if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_PREALLOC) {
1187 		ret = -EINVAL;
1188 		btrfs_abort_transaction(trans, ret);
1189 		goto out;
1190 	}
1191 	extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1192 	if (key.offset > start || extent_end < end) {
1193 		ret = -EINVAL;
1194 		btrfs_abort_transaction(trans, ret);
1195 		goto out;
1196 	}
1197 
1198 	bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1199 	num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1200 	orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
1201 	memcpy(&new_key, &key, sizeof(new_key));
1202 
1203 	if (start == key.offset && end < extent_end) {
1204 		other_start = 0;
1205 		other_end = start;
1206 		if (extent_mergeable(leaf, path->slots[0] - 1,
1207 				     ino, bytenr, orig_offset,
1208 				     &other_start, &other_end)) {
1209 			new_key.offset = end;
1210 			btrfs_set_item_key_safe(fs_info, path, &new_key);
1211 			fi = btrfs_item_ptr(leaf, path->slots[0],
1212 					    struct btrfs_file_extent_item);
1213 			btrfs_set_file_extent_generation(leaf, fi,
1214 							 trans->transid);
1215 			btrfs_set_file_extent_num_bytes(leaf, fi,
1216 							extent_end - end);
1217 			btrfs_set_file_extent_offset(leaf, fi,
1218 						     end - orig_offset);
1219 			fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1220 					    struct btrfs_file_extent_item);
1221 			btrfs_set_file_extent_generation(leaf, fi,
1222 							 trans->transid);
1223 			btrfs_set_file_extent_num_bytes(leaf, fi,
1224 							end - other_start);
1225 			btrfs_mark_buffer_dirty(leaf);
1226 			goto out;
1227 		}
1228 	}
1229 
1230 	if (start > key.offset && end == extent_end) {
1231 		other_start = end;
1232 		other_end = 0;
1233 		if (extent_mergeable(leaf, path->slots[0] + 1,
1234 				     ino, bytenr, orig_offset,
1235 				     &other_start, &other_end)) {
1236 			fi = btrfs_item_ptr(leaf, path->slots[0],
1237 					    struct btrfs_file_extent_item);
1238 			btrfs_set_file_extent_num_bytes(leaf, fi,
1239 							start - key.offset);
1240 			btrfs_set_file_extent_generation(leaf, fi,
1241 							 trans->transid);
1242 			path->slots[0]++;
1243 			new_key.offset = start;
1244 			btrfs_set_item_key_safe(fs_info, path, &new_key);
1245 
1246 			fi = btrfs_item_ptr(leaf, path->slots[0],
1247 					    struct btrfs_file_extent_item);
1248 			btrfs_set_file_extent_generation(leaf, fi,
1249 							 trans->transid);
1250 			btrfs_set_file_extent_num_bytes(leaf, fi,
1251 							other_end - start);
1252 			btrfs_set_file_extent_offset(leaf, fi,
1253 						     start - orig_offset);
1254 			btrfs_mark_buffer_dirty(leaf);
1255 			goto out;
1256 		}
1257 	}
1258 
1259 	while (start > key.offset || end < extent_end) {
1260 		if (key.offset == start)
1261 			split = end;
1262 
1263 		new_key.offset = split;
1264 		ret = btrfs_duplicate_item(trans, root, path, &new_key);
1265 		if (ret == -EAGAIN) {
1266 			btrfs_release_path(path);
1267 			goto again;
1268 		}
1269 		if (ret < 0) {
1270 			btrfs_abort_transaction(trans, ret);
1271 			goto out;
1272 		}
1273 
1274 		leaf = path->nodes[0];
1275 		fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1276 				    struct btrfs_file_extent_item);
1277 		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1278 		btrfs_set_file_extent_num_bytes(leaf, fi,
1279 						split - key.offset);
1280 
1281 		fi = btrfs_item_ptr(leaf, path->slots[0],
1282 				    struct btrfs_file_extent_item);
1283 
1284 		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1285 		btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
1286 		btrfs_set_file_extent_num_bytes(leaf, fi,
1287 						extent_end - split);
1288 		btrfs_mark_buffer_dirty(leaf);
1289 
1290 		ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
1291 					   0, root->root_key.objectid,
1292 					   ino, orig_offset);
1293 		if (ret) {
1294 			btrfs_abort_transaction(trans, ret);
1295 			goto out;
1296 		}
1297 
1298 		if (split == start) {
1299 			key.offset = start;
1300 		} else {
1301 			if (start != key.offset) {
1302 				ret = -EINVAL;
1303 				btrfs_abort_transaction(trans, ret);
1304 				goto out;
1305 			}
1306 			path->slots[0]--;
1307 			extent_end = end;
1308 		}
1309 		recow = 1;
1310 	}
1311 
1312 	other_start = end;
1313 	other_end = 0;
1314 	if (extent_mergeable(leaf, path->slots[0] + 1,
1315 			     ino, bytenr, orig_offset,
1316 			     &other_start, &other_end)) {
1317 		if (recow) {
1318 			btrfs_release_path(path);
1319 			goto again;
1320 		}
1321 		extent_end = other_end;
1322 		del_slot = path->slots[0] + 1;
1323 		del_nr++;
1324 		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1325 					0, root->root_key.objectid,
1326 					ino, orig_offset);
1327 		if (ret) {
1328 			btrfs_abort_transaction(trans, ret);
1329 			goto out;
1330 		}
1331 	}
1332 	other_start = 0;
1333 	other_end = start;
1334 	if (extent_mergeable(leaf, path->slots[0] - 1,
1335 			     ino, bytenr, orig_offset,
1336 			     &other_start, &other_end)) {
1337 		if (recow) {
1338 			btrfs_release_path(path);
1339 			goto again;
1340 		}
1341 		key.offset = other_start;
1342 		del_slot = path->slots[0];
1343 		del_nr++;
1344 		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1345 					0, root->root_key.objectid,
1346 					ino, orig_offset);
1347 		if (ret) {
1348 			btrfs_abort_transaction(trans, ret);
1349 			goto out;
1350 		}
1351 	}
1352 	if (del_nr == 0) {
1353 		fi = btrfs_item_ptr(leaf, path->slots[0],
1354 			   struct btrfs_file_extent_item);
1355 		btrfs_set_file_extent_type(leaf, fi,
1356 					   BTRFS_FILE_EXTENT_REG);
1357 		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1358 		btrfs_mark_buffer_dirty(leaf);
1359 	} else {
1360 		fi = btrfs_item_ptr(leaf, del_slot - 1,
1361 			   struct btrfs_file_extent_item);
1362 		btrfs_set_file_extent_type(leaf, fi,
1363 					   BTRFS_FILE_EXTENT_REG);
1364 		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1365 		btrfs_set_file_extent_num_bytes(leaf, fi,
1366 						extent_end - key.offset);
1367 		btrfs_mark_buffer_dirty(leaf);
1368 
1369 		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1370 		if (ret < 0) {
1371 			btrfs_abort_transaction(trans, ret);
1372 			goto out;
1373 		}
1374 	}
1375 out:
1376 	btrfs_free_path(path);
1377 	return ret;
1378 }
1379 
1380 /*
1381  * on error we return an unlocked page and the error value
1382  * on success we return a locked page and 0
1383  */
prepare_uptodate_page(struct inode * inode,struct page * page,u64 pos,bool force_uptodate)1384 static int prepare_uptodate_page(struct inode *inode,
1385 				 struct page *page, u64 pos,
1386 				 bool force_uptodate)
1387 {
1388 	int ret = 0;
1389 
1390 	if (((pos & (PAGE_SIZE - 1)) || force_uptodate) &&
1391 	    !PageUptodate(page)) {
1392 		ret = btrfs_readpage(NULL, page);
1393 		if (ret)
1394 			return ret;
1395 		lock_page(page);
1396 		if (!PageUptodate(page)) {
1397 			unlock_page(page);
1398 			return -EIO;
1399 		}
1400 		if (page->mapping != inode->i_mapping) {
1401 			unlock_page(page);
1402 			return -EAGAIN;
1403 		}
1404 	}
1405 	return 0;
1406 }
1407 
1408 /*
1409  * this just gets pages into the page cache and locks them down.
1410  */
prepare_pages(struct inode * inode,struct page ** pages,size_t num_pages,loff_t pos,size_t write_bytes,bool force_uptodate)1411 static noinline int prepare_pages(struct inode *inode, struct page **pages,
1412 				  size_t num_pages, loff_t pos,
1413 				  size_t write_bytes, bool force_uptodate)
1414 {
1415 	int i;
1416 	unsigned long index = pos >> PAGE_SHIFT;
1417 	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1418 	int err = 0;
1419 	int faili;
1420 
1421 	for (i = 0; i < num_pages; i++) {
1422 again:
1423 		pages[i] = find_or_create_page(inode->i_mapping, index + i,
1424 					       mask | __GFP_WRITE);
1425 		if (!pages[i]) {
1426 			faili = i - 1;
1427 			err = -ENOMEM;
1428 			goto fail;
1429 		}
1430 
1431 		if (i == 0)
1432 			err = prepare_uptodate_page(inode, pages[i], pos,
1433 						    force_uptodate);
1434 		if (!err && i == num_pages - 1)
1435 			err = prepare_uptodate_page(inode, pages[i],
1436 						    pos + write_bytes, false);
1437 		if (err) {
1438 			put_page(pages[i]);
1439 			if (err == -EAGAIN) {
1440 				err = 0;
1441 				goto again;
1442 			}
1443 			faili = i - 1;
1444 			goto fail;
1445 		}
1446 		wait_on_page_writeback(pages[i]);
1447 	}
1448 
1449 	return 0;
1450 fail:
1451 	while (faili >= 0) {
1452 		unlock_page(pages[faili]);
1453 		put_page(pages[faili]);
1454 		faili--;
1455 	}
1456 	return err;
1457 
1458 }
1459 
1460 /*
1461  * This function locks the extent and properly waits for data=ordered extents
1462  * to finish before allowing the pages to be modified if need.
1463  *
1464  * The return value:
1465  * 1 - the extent is locked
1466  * 0 - the extent is not locked, and everything is OK
1467  * -EAGAIN - need re-prepare the pages
1468  * the other < 0 number - Something wrong happens
1469  */
1470 static noinline int
lock_and_cleanup_extent_if_need(struct btrfs_inode * inode,struct page ** pages,size_t num_pages,loff_t pos,size_t write_bytes,u64 * lockstart,u64 * lockend,struct extent_state ** cached_state)1471 lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page **pages,
1472 				size_t num_pages, loff_t pos,
1473 				size_t write_bytes,
1474 				u64 *lockstart, u64 *lockend,
1475 				struct extent_state **cached_state)
1476 {
1477 	struct btrfs_fs_info *fs_info = inode->root->fs_info;
1478 	u64 start_pos;
1479 	u64 last_pos;
1480 	int i;
1481 	int ret = 0;
1482 
1483 	start_pos = round_down(pos, fs_info->sectorsize);
1484 	last_pos = start_pos
1485 		+ round_up(pos + write_bytes - start_pos,
1486 			   fs_info->sectorsize) - 1;
1487 
1488 	if (start_pos < inode->vfs_inode.i_size) {
1489 		struct btrfs_ordered_extent *ordered;
1490 
1491 		lock_extent_bits(&inode->io_tree, start_pos, last_pos,
1492 				cached_state);
1493 		ordered = btrfs_lookup_ordered_range(inode, start_pos,
1494 						     last_pos - start_pos + 1);
1495 		if (ordered &&
1496 		    ordered->file_offset + ordered->len > start_pos &&
1497 		    ordered->file_offset <= last_pos) {
1498 			unlock_extent_cached(&inode->io_tree, start_pos,
1499 					last_pos, cached_state);
1500 			for (i = 0; i < num_pages; i++) {
1501 				unlock_page(pages[i]);
1502 				put_page(pages[i]);
1503 			}
1504 			btrfs_start_ordered_extent(&inode->vfs_inode,
1505 					ordered, 1);
1506 			btrfs_put_ordered_extent(ordered);
1507 			return -EAGAIN;
1508 		}
1509 		if (ordered)
1510 			btrfs_put_ordered_extent(ordered);
1511 
1512 		*lockstart = start_pos;
1513 		*lockend = last_pos;
1514 		ret = 1;
1515 	}
1516 
1517 	/*
1518 	 * It's possible the pages are dirty right now, but we don't want
1519 	 * to clean them yet because copy_from_user may catch a page fault
1520 	 * and we might have to fall back to one page at a time.  If that
1521 	 * happens, we'll unlock these pages and we'd have a window where
1522 	 * reclaim could sneak in and drop the once-dirty page on the floor
1523 	 * without writing it.
1524 	 *
1525 	 * We have the pages locked and the extent range locked, so there's
1526 	 * no way someone can start IO on any dirty pages in this range.
1527 	 *
1528 	 * We'll call btrfs_dirty_pages() later on, and that will flip around
1529 	 * delalloc bits and dirty the pages as required.
1530 	 */
1531 	for (i = 0; i < num_pages; i++) {
1532 		set_page_extent_mapped(pages[i]);
1533 		WARN_ON(!PageLocked(pages[i]));
1534 	}
1535 
1536 	return ret;
1537 }
1538 
check_can_nocow(struct btrfs_inode * inode,loff_t pos,size_t * write_bytes)1539 static noinline int check_can_nocow(struct btrfs_inode *inode, loff_t pos,
1540 				    size_t *write_bytes)
1541 {
1542 	struct btrfs_fs_info *fs_info = inode->root->fs_info;
1543 	struct btrfs_root *root = inode->root;
1544 	struct btrfs_ordered_extent *ordered;
1545 	u64 lockstart, lockend;
1546 	u64 num_bytes;
1547 	int ret;
1548 
1549 	ret = btrfs_start_write_no_snapshotting(root);
1550 	if (!ret)
1551 		return -ENOSPC;
1552 
1553 	lockstart = round_down(pos, fs_info->sectorsize);
1554 	lockend = round_up(pos + *write_bytes,
1555 			   fs_info->sectorsize) - 1;
1556 
1557 	while (1) {
1558 		lock_extent(&inode->io_tree, lockstart, lockend);
1559 		ordered = btrfs_lookup_ordered_range(inode, lockstart,
1560 						     lockend - lockstart + 1);
1561 		if (!ordered) {
1562 			break;
1563 		}
1564 		unlock_extent(&inode->io_tree, lockstart, lockend);
1565 		btrfs_start_ordered_extent(&inode->vfs_inode, ordered, 1);
1566 		btrfs_put_ordered_extent(ordered);
1567 	}
1568 
1569 	num_bytes = lockend - lockstart + 1;
1570 	ret = can_nocow_extent(&inode->vfs_inode, lockstart, &num_bytes,
1571 			NULL, NULL, NULL);
1572 	if (ret <= 0) {
1573 		ret = 0;
1574 		btrfs_end_write_no_snapshotting(root);
1575 	} else {
1576 		*write_bytes = min_t(size_t, *write_bytes ,
1577 				     num_bytes - pos + lockstart);
1578 	}
1579 
1580 	unlock_extent(&inode->io_tree, lockstart, lockend);
1581 
1582 	return ret;
1583 }
1584 
btrfs_buffered_write(struct kiocb * iocb,struct iov_iter * i)1585 static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
1586 					       struct iov_iter *i)
1587 {
1588 	struct file *file = iocb->ki_filp;
1589 	loff_t pos = iocb->ki_pos;
1590 	struct inode *inode = file_inode(file);
1591 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1592 	struct btrfs_root *root = BTRFS_I(inode)->root;
1593 	struct page **pages = NULL;
1594 	struct extent_changeset *data_reserved = NULL;
1595 	u64 release_bytes = 0;
1596 	u64 lockstart;
1597 	u64 lockend;
1598 	size_t num_written = 0;
1599 	int nrptrs;
1600 	int ret = 0;
1601 	bool only_release_metadata = false;
1602 	bool force_page_uptodate = false;
1603 
1604 	nrptrs = min(DIV_ROUND_UP(iov_iter_count(i), PAGE_SIZE),
1605 			PAGE_SIZE / (sizeof(struct page *)));
1606 	nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
1607 	nrptrs = max(nrptrs, 8);
1608 	pages = kmalloc_array(nrptrs, sizeof(struct page *), GFP_KERNEL);
1609 	if (!pages)
1610 		return -ENOMEM;
1611 
1612 	while (iov_iter_count(i) > 0) {
1613 		size_t offset = pos & (PAGE_SIZE - 1);
1614 		struct extent_state *cached_state = NULL;
1615 		size_t sector_offset;
1616 		size_t write_bytes = min(iov_iter_count(i),
1617 					 nrptrs * (size_t)PAGE_SIZE -
1618 					 offset);
1619 		size_t num_pages = DIV_ROUND_UP(write_bytes + offset,
1620 						PAGE_SIZE);
1621 		size_t reserve_bytes;
1622 		size_t dirty_pages;
1623 		size_t copied;
1624 		size_t dirty_sectors;
1625 		size_t num_sectors;
1626 		int extents_locked;
1627 
1628 		WARN_ON(num_pages > nrptrs);
1629 
1630 		/*
1631 		 * Fault pages before locking them in prepare_pages
1632 		 * to avoid recursive lock
1633 		 */
1634 		if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1635 			ret = -EFAULT;
1636 			break;
1637 		}
1638 
1639 		only_release_metadata = false;
1640 		sector_offset = pos & (fs_info->sectorsize - 1);
1641 		reserve_bytes = round_up(write_bytes + sector_offset,
1642 				fs_info->sectorsize);
1643 
1644 		extent_changeset_release(data_reserved);
1645 		ret = btrfs_check_data_free_space(inode, &data_reserved, pos,
1646 						  write_bytes);
1647 		if (ret < 0) {
1648 			if ((BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
1649 						      BTRFS_INODE_PREALLOC)) &&
1650 			    check_can_nocow(BTRFS_I(inode), pos,
1651 					&write_bytes) > 0) {
1652 				/*
1653 				 * For nodata cow case, no need to reserve
1654 				 * data space.
1655 				 */
1656 				only_release_metadata = true;
1657 				/*
1658 				 * our prealloc extent may be smaller than
1659 				 * write_bytes, so scale down.
1660 				 */
1661 				num_pages = DIV_ROUND_UP(write_bytes + offset,
1662 							 PAGE_SIZE);
1663 				reserve_bytes = round_up(write_bytes +
1664 							 sector_offset,
1665 							 fs_info->sectorsize);
1666 			} else {
1667 				break;
1668 			}
1669 		}
1670 
1671 		WARN_ON(reserve_bytes == 0);
1672 		ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
1673 				reserve_bytes);
1674 		if (ret) {
1675 			if (!only_release_metadata)
1676 				btrfs_free_reserved_data_space(inode,
1677 						data_reserved, pos,
1678 						write_bytes);
1679 			else
1680 				btrfs_end_write_no_snapshotting(root);
1681 			break;
1682 		}
1683 
1684 		release_bytes = reserve_bytes;
1685 again:
1686 		/*
1687 		 * This is going to setup the pages array with the number of
1688 		 * pages we want, so we don't really need to worry about the
1689 		 * contents of pages from loop to loop
1690 		 */
1691 		ret = prepare_pages(inode, pages, num_pages,
1692 				    pos, write_bytes,
1693 				    force_page_uptodate);
1694 		if (ret) {
1695 			btrfs_delalloc_release_extents(BTRFS_I(inode),
1696 						       reserve_bytes);
1697 			break;
1698 		}
1699 
1700 		extents_locked = lock_and_cleanup_extent_if_need(
1701 				BTRFS_I(inode), pages,
1702 				num_pages, pos, write_bytes, &lockstart,
1703 				&lockend, &cached_state);
1704 		if (extents_locked < 0) {
1705 			if (extents_locked == -EAGAIN)
1706 				goto again;
1707 			btrfs_delalloc_release_extents(BTRFS_I(inode),
1708 						       reserve_bytes);
1709 			ret = extents_locked;
1710 			break;
1711 		}
1712 
1713 		copied = btrfs_copy_from_user(pos, write_bytes, pages, i);
1714 
1715 		num_sectors = BTRFS_BYTES_TO_BLKS(fs_info, reserve_bytes);
1716 		dirty_sectors = round_up(copied + sector_offset,
1717 					fs_info->sectorsize);
1718 		dirty_sectors = BTRFS_BYTES_TO_BLKS(fs_info, dirty_sectors);
1719 
1720 		/*
1721 		 * if we have trouble faulting in the pages, fall
1722 		 * back to one page at a time
1723 		 */
1724 		if (copied < write_bytes)
1725 			nrptrs = 1;
1726 
1727 		if (copied == 0) {
1728 			force_page_uptodate = true;
1729 			dirty_sectors = 0;
1730 			dirty_pages = 0;
1731 		} else {
1732 			force_page_uptodate = false;
1733 			dirty_pages = DIV_ROUND_UP(copied + offset,
1734 						   PAGE_SIZE);
1735 		}
1736 
1737 		if (num_sectors > dirty_sectors) {
1738 			/* release everything except the sectors we dirtied */
1739 			release_bytes -= dirty_sectors <<
1740 						fs_info->sb->s_blocksize_bits;
1741 			if (only_release_metadata) {
1742 				btrfs_delalloc_release_metadata(BTRFS_I(inode),
1743 							release_bytes, true);
1744 			} else {
1745 				u64 __pos;
1746 
1747 				__pos = round_down(pos,
1748 						   fs_info->sectorsize) +
1749 					(dirty_pages << PAGE_SHIFT);
1750 				btrfs_delalloc_release_space(inode,
1751 						data_reserved, __pos,
1752 						release_bytes, true);
1753 			}
1754 		}
1755 
1756 		release_bytes = round_up(copied + sector_offset,
1757 					fs_info->sectorsize);
1758 
1759 		if (copied > 0)
1760 			ret = btrfs_dirty_pages(inode, pages, dirty_pages,
1761 						pos, copied, &cached_state);
1762 
1763 		/*
1764 		 * If we have not locked the extent range, because the range's
1765 		 * start offset is >= i_size, we might still have a non-NULL
1766 		 * cached extent state, acquired while marking the extent range
1767 		 * as delalloc through btrfs_dirty_pages(). Therefore free any
1768 		 * possible cached extent state to avoid a memory leak.
1769 		 */
1770 		if (extents_locked)
1771 			unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1772 					     lockstart, lockend, &cached_state);
1773 		else
1774 			free_extent_state(cached_state);
1775 
1776 		btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes);
1777 		if (ret) {
1778 			btrfs_drop_pages(pages, num_pages);
1779 			break;
1780 		}
1781 
1782 		release_bytes = 0;
1783 		if (only_release_metadata)
1784 			btrfs_end_write_no_snapshotting(root);
1785 
1786 		if (only_release_metadata && copied > 0) {
1787 			lockstart = round_down(pos,
1788 					       fs_info->sectorsize);
1789 			lockend = round_up(pos + copied,
1790 					   fs_info->sectorsize) - 1;
1791 
1792 			set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
1793 				       lockend, EXTENT_NORESERVE, NULL,
1794 				       NULL, GFP_NOFS);
1795 		}
1796 
1797 		btrfs_drop_pages(pages, num_pages);
1798 
1799 		cond_resched();
1800 
1801 		balance_dirty_pages_ratelimited(inode->i_mapping);
1802 		if (dirty_pages < (fs_info->nodesize >> PAGE_SHIFT) + 1)
1803 			btrfs_btree_balance_dirty(fs_info);
1804 
1805 		pos += copied;
1806 		num_written += copied;
1807 	}
1808 
1809 	kfree(pages);
1810 
1811 	if (release_bytes) {
1812 		if (only_release_metadata) {
1813 			btrfs_end_write_no_snapshotting(root);
1814 			btrfs_delalloc_release_metadata(BTRFS_I(inode),
1815 					release_bytes, true);
1816 		} else {
1817 			btrfs_delalloc_release_space(inode, data_reserved,
1818 					round_down(pos, fs_info->sectorsize),
1819 					release_bytes, true);
1820 		}
1821 	}
1822 
1823 	extent_changeset_free(data_reserved);
1824 	return num_written ? num_written : ret;
1825 }
1826 
__btrfs_direct_write(struct kiocb * iocb,struct iov_iter * from)1827 static ssize_t __btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
1828 {
1829 	struct file *file = iocb->ki_filp;
1830 	struct inode *inode = file_inode(file);
1831 	loff_t pos;
1832 	ssize_t written;
1833 	ssize_t written_buffered;
1834 	loff_t endbyte;
1835 	int err;
1836 
1837 	written = generic_file_direct_write(iocb, from);
1838 
1839 	if (written < 0 || !iov_iter_count(from))
1840 		return written;
1841 
1842 	pos = iocb->ki_pos;
1843 	written_buffered = btrfs_buffered_write(iocb, from);
1844 	if (written_buffered < 0) {
1845 		err = written_buffered;
1846 		goto out;
1847 	}
1848 	/*
1849 	 * Ensure all data is persisted. We want the next direct IO read to be
1850 	 * able to read what was just written.
1851 	 */
1852 	endbyte = pos + written_buffered - 1;
1853 	err = btrfs_fdatawrite_range(inode, pos, endbyte);
1854 	if (err)
1855 		goto out;
1856 	err = filemap_fdatawait_range(inode->i_mapping, pos, endbyte);
1857 	if (err)
1858 		goto out;
1859 	written += written_buffered;
1860 	iocb->ki_pos = pos + written_buffered;
1861 	invalidate_mapping_pages(file->f_mapping, pos >> PAGE_SHIFT,
1862 				 endbyte >> PAGE_SHIFT);
1863 out:
1864 	return written ? written : err;
1865 }
1866 
update_time_for_write(struct inode * inode)1867 static void update_time_for_write(struct inode *inode)
1868 {
1869 	struct timespec64 now;
1870 
1871 	if (IS_NOCMTIME(inode))
1872 		return;
1873 
1874 	now = current_time(inode);
1875 	if (!timespec64_equal(&inode->i_mtime, &now))
1876 		inode->i_mtime = now;
1877 
1878 	if (!timespec64_equal(&inode->i_ctime, &now))
1879 		inode->i_ctime = now;
1880 
1881 	if (IS_I_VERSION(inode))
1882 		inode_inc_iversion(inode);
1883 }
1884 
btrfs_file_write_iter(struct kiocb * iocb,struct iov_iter * from)1885 static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
1886 				    struct iov_iter *from)
1887 {
1888 	struct file *file = iocb->ki_filp;
1889 	struct inode *inode = file_inode(file);
1890 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1891 	struct btrfs_root *root = BTRFS_I(inode)->root;
1892 	u64 start_pos;
1893 	u64 end_pos;
1894 	ssize_t num_written = 0;
1895 	bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
1896 	ssize_t err;
1897 	loff_t pos;
1898 	size_t count;
1899 	loff_t oldsize;
1900 	int clean_page = 0;
1901 
1902 	if (!(iocb->ki_flags & IOCB_DIRECT) &&
1903 	    (iocb->ki_flags & IOCB_NOWAIT))
1904 		return -EOPNOTSUPP;
1905 
1906 	if (iocb->ki_flags & IOCB_NOWAIT) {
1907 		if (!inode_trylock(inode))
1908 			return -EAGAIN;
1909 	} else {
1910 		inode_lock(inode);
1911 	}
1912 
1913 	err = generic_write_checks(iocb, from);
1914 	if (err <= 0) {
1915 		inode_unlock(inode);
1916 		return err;
1917 	}
1918 
1919 	pos = iocb->ki_pos;
1920 	count = iov_iter_count(from);
1921 	if (iocb->ki_flags & IOCB_NOWAIT) {
1922 		/*
1923 		 * We will allocate space in case nodatacow is not set,
1924 		 * so bail
1925 		 */
1926 		if (!(BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
1927 					      BTRFS_INODE_PREALLOC)) ||
1928 		    check_can_nocow(BTRFS_I(inode), pos, &count) <= 0) {
1929 			inode_unlock(inode);
1930 			return -EAGAIN;
1931 		}
1932 	}
1933 
1934 	current->backing_dev_info = inode_to_bdi(inode);
1935 	err = file_remove_privs(file);
1936 	if (err) {
1937 		inode_unlock(inode);
1938 		goto out;
1939 	}
1940 
1941 	/*
1942 	 * If BTRFS flips readonly due to some impossible error
1943 	 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1944 	 * although we have opened a file as writable, we have
1945 	 * to stop this write operation to ensure FS consistency.
1946 	 */
1947 	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
1948 		inode_unlock(inode);
1949 		err = -EROFS;
1950 		goto out;
1951 	}
1952 
1953 	/*
1954 	 * We reserve space for updating the inode when we reserve space for the
1955 	 * extent we are going to write, so we will enospc out there.  We don't
1956 	 * need to start yet another transaction to update the inode as we will
1957 	 * update the inode when we finish writing whatever data we write.
1958 	 */
1959 	update_time_for_write(inode);
1960 
1961 	start_pos = round_down(pos, fs_info->sectorsize);
1962 	oldsize = i_size_read(inode);
1963 	if (start_pos > oldsize) {
1964 		/* Expand hole size to cover write data, preventing empty gap */
1965 		end_pos = round_up(pos + count,
1966 				   fs_info->sectorsize);
1967 		err = btrfs_cont_expand(inode, oldsize, end_pos);
1968 		if (err) {
1969 			inode_unlock(inode);
1970 			goto out;
1971 		}
1972 		if (start_pos > round_up(oldsize, fs_info->sectorsize))
1973 			clean_page = 1;
1974 	}
1975 
1976 	if (sync)
1977 		atomic_inc(&BTRFS_I(inode)->sync_writers);
1978 
1979 	if (iocb->ki_flags & IOCB_DIRECT) {
1980 		num_written = __btrfs_direct_write(iocb, from);
1981 	} else {
1982 		num_written = btrfs_buffered_write(iocb, from);
1983 		if (num_written > 0)
1984 			iocb->ki_pos = pos + num_written;
1985 		if (clean_page)
1986 			pagecache_isize_extended(inode, oldsize,
1987 						i_size_read(inode));
1988 	}
1989 
1990 	inode_unlock(inode);
1991 
1992 	/*
1993 	 * We also have to set last_sub_trans to the current log transid,
1994 	 * otherwise subsequent syncs to a file that's been synced in this
1995 	 * transaction will appear to have already occurred.
1996 	 */
1997 	spin_lock(&BTRFS_I(inode)->lock);
1998 	BTRFS_I(inode)->last_sub_trans = root->log_transid;
1999 	spin_unlock(&BTRFS_I(inode)->lock);
2000 	if (num_written > 0)
2001 		num_written = generic_write_sync(iocb, num_written);
2002 
2003 	if (sync)
2004 		atomic_dec(&BTRFS_I(inode)->sync_writers);
2005 out:
2006 	current->backing_dev_info = NULL;
2007 	return num_written ? num_written : err;
2008 }
2009 
btrfs_release_file(struct inode * inode,struct file * filp)2010 int btrfs_release_file(struct inode *inode, struct file *filp)
2011 {
2012 	struct btrfs_file_private *private = filp->private_data;
2013 
2014 	if (private && private->filldir_buf)
2015 		kfree(private->filldir_buf);
2016 	kfree(private);
2017 	filp->private_data = NULL;
2018 
2019 	/*
2020 	 * ordered_data_close is set by settattr when we are about to truncate
2021 	 * a file from a non-zero size to a zero size.  This tries to
2022 	 * flush down new bytes that may have been written if the
2023 	 * application were using truncate to replace a file in place.
2024 	 */
2025 	if (test_and_clear_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
2026 			       &BTRFS_I(inode)->runtime_flags))
2027 			filemap_flush(inode->i_mapping);
2028 	return 0;
2029 }
2030 
start_ordered_ops(struct inode * inode,loff_t start,loff_t end)2031 static int start_ordered_ops(struct inode *inode, loff_t start, loff_t end)
2032 {
2033 	int ret;
2034 	struct blk_plug plug;
2035 
2036 	/*
2037 	 * This is only called in fsync, which would do synchronous writes, so
2038 	 * a plug can merge adjacent IOs as much as possible.  Esp. in case of
2039 	 * multiple disks using raid profile, a large IO can be split to
2040 	 * several segments of stripe length (currently 64K).
2041 	 */
2042 	blk_start_plug(&plug);
2043 	atomic_inc(&BTRFS_I(inode)->sync_writers);
2044 	ret = btrfs_fdatawrite_range(inode, start, end);
2045 	atomic_dec(&BTRFS_I(inode)->sync_writers);
2046 	blk_finish_plug(&plug);
2047 
2048 	return ret;
2049 }
2050 
2051 /*
2052  * fsync call for both files and directories.  This logs the inode into
2053  * the tree log instead of forcing full commits whenever possible.
2054  *
2055  * It needs to call filemap_fdatawait so that all ordered extent updates are
2056  * in the metadata btree are up to date for copying to the log.
2057  *
2058  * It drops the inode mutex before doing the tree log commit.  This is an
2059  * important optimization for directories because holding the mutex prevents
2060  * new operations on the dir while we write to disk.
2061  */
btrfs_sync_file(struct file * file,loff_t start,loff_t end,int datasync)2062 int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
2063 {
2064 	struct dentry *dentry = file_dentry(file);
2065 	struct inode *inode = d_inode(dentry);
2066 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2067 	struct btrfs_root *root = BTRFS_I(inode)->root;
2068 	struct btrfs_trans_handle *trans;
2069 	struct btrfs_log_ctx ctx;
2070 	int ret = 0, err;
2071 
2072 	trace_btrfs_sync_file(file, datasync);
2073 
2074 	btrfs_init_log_ctx(&ctx, inode);
2075 
2076 	/*
2077 	 * Set the range to full if the NO_HOLES feature is not enabled.
2078 	 * This is to avoid missing file extent items representing holes after
2079 	 * replaying the log.
2080 	 */
2081 	if (!btrfs_fs_incompat(fs_info, NO_HOLES)) {
2082 		start = 0;
2083 		end = LLONG_MAX;
2084 	}
2085 
2086 	/*
2087 	 * We write the dirty pages in the range and wait until they complete
2088 	 * out of the ->i_mutex. If so, we can flush the dirty pages by
2089 	 * multi-task, and make the performance up.  See
2090 	 * btrfs_wait_ordered_range for an explanation of the ASYNC check.
2091 	 */
2092 	ret = start_ordered_ops(inode, start, end);
2093 	if (ret)
2094 		goto out;
2095 
2096 	inode_lock(inode);
2097 
2098 	/*
2099 	 * We take the dio_sem here because the tree log stuff can race with
2100 	 * lockless dio writes and get an extent map logged for an extent we
2101 	 * never waited on.  We need it this high up for lockdep reasons.
2102 	 */
2103 	down_write(&BTRFS_I(inode)->dio_sem);
2104 
2105 	atomic_inc(&root->log_batch);
2106 
2107 	/*
2108 	 * If the inode needs a full sync, make sure we use a full range to
2109 	 * avoid log tree corruption, due to hole detection racing with ordered
2110 	 * extent completion for adjacent ranges, and assertion failures during
2111 	 * hole detection. Do this while holding the inode lock, to avoid races
2112 	 * with other tasks.
2113 	 */
2114 	if (test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2115 		     &BTRFS_I(inode)->runtime_flags)) {
2116 		start = 0;
2117 		end = LLONG_MAX;
2118 	}
2119 
2120 	/*
2121 	 * Before we acquired the inode's lock, someone may have dirtied more
2122 	 * pages in the target range. We need to make sure that writeback for
2123 	 * any such pages does not start while we are logging the inode, because
2124 	 * if it does, any of the following might happen when we are not doing a
2125 	 * full inode sync:
2126 	 *
2127 	 * 1) We log an extent after its writeback finishes but before its
2128 	 *    checksums are added to the csum tree, leading to -EIO errors
2129 	 *    when attempting to read the extent after a log replay.
2130 	 *
2131 	 * 2) We can end up logging an extent before its writeback finishes.
2132 	 *    Therefore after the log replay we will have a file extent item
2133 	 *    pointing to an unwritten extent (and no data checksums as well).
2134 	 *
2135 	 * So trigger writeback for any eventual new dirty pages and then we
2136 	 * wait for all ordered extents to complete below.
2137 	 */
2138 	ret = start_ordered_ops(inode, start, end);
2139 	if (ret) {
2140 		up_write(&BTRFS_I(inode)->dio_sem);
2141 		inode_unlock(inode);
2142 		goto out;
2143 	}
2144 
2145 	/*
2146 	 * We have to do this here to avoid the priority inversion of waiting on
2147 	 * IO of a lower priority task while holding a transaciton open.
2148 	 *
2149 	 * Also, the range length can be represented by u64, we have to do the
2150 	 * typecasts to avoid signed overflow if it's [0, LLONG_MAX].
2151 	 */
2152 	ret = btrfs_wait_ordered_range(inode, start, (u64)end - (u64)start + 1);
2153 	if (ret) {
2154 		up_write(&BTRFS_I(inode)->dio_sem);
2155 		inode_unlock(inode);
2156 		goto out;
2157 	}
2158 	atomic_inc(&root->log_batch);
2159 
2160 	smp_mb();
2161 	if (btrfs_inode_in_log(BTRFS_I(inode), fs_info->generation) ||
2162 	    BTRFS_I(inode)->last_trans <= fs_info->last_trans_committed) {
2163 		/*
2164 		 * We've had everything committed since the last time we were
2165 		 * modified so clear this flag in case it was set for whatever
2166 		 * reason, it's no longer relevant.
2167 		 */
2168 		clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2169 			  &BTRFS_I(inode)->runtime_flags);
2170 		/*
2171 		 * An ordered extent might have started before and completed
2172 		 * already with io errors, in which case the inode was not
2173 		 * updated and we end up here. So check the inode's mapping
2174 		 * for any errors that might have happened since we last
2175 		 * checked called fsync.
2176 		 */
2177 		ret = filemap_check_wb_err(inode->i_mapping, file->f_wb_err);
2178 		up_write(&BTRFS_I(inode)->dio_sem);
2179 		inode_unlock(inode);
2180 		goto out;
2181 	}
2182 
2183 	/*
2184 	 * We use start here because we will need to wait on the IO to complete
2185 	 * in btrfs_sync_log, which could require joining a transaction (for
2186 	 * example checking cross references in the nocow path).  If we use join
2187 	 * here we could get into a situation where we're waiting on IO to
2188 	 * happen that is blocked on a transaction trying to commit.  With start
2189 	 * we inc the extwriter counter, so we wait for all extwriters to exit
2190 	 * before we start blocking join'ers.  This comment is to keep somebody
2191 	 * from thinking they are super smart and changing this to
2192 	 * btrfs_join_transaction *cough*Josef*cough*.
2193 	 */
2194 	trans = btrfs_start_transaction(root, 0);
2195 	if (IS_ERR(trans)) {
2196 		ret = PTR_ERR(trans);
2197 		up_write(&BTRFS_I(inode)->dio_sem);
2198 		inode_unlock(inode);
2199 		goto out;
2200 	}
2201 	trans->sync = true;
2202 
2203 	ret = btrfs_log_dentry_safe(trans, dentry, start, end, &ctx);
2204 	if (ret < 0) {
2205 		/* Fallthrough and commit/free transaction. */
2206 		ret = 1;
2207 	}
2208 
2209 	/* we've logged all the items and now have a consistent
2210 	 * version of the file in the log.  It is possible that
2211 	 * someone will come in and modify the file, but that's
2212 	 * fine because the log is consistent on disk, and we
2213 	 * have references to all of the file's extents
2214 	 *
2215 	 * It is possible that someone will come in and log the
2216 	 * file again, but that will end up using the synchronization
2217 	 * inside btrfs_sync_log to keep things safe.
2218 	 */
2219 	up_write(&BTRFS_I(inode)->dio_sem);
2220 	inode_unlock(inode);
2221 
2222 	/*
2223 	 * If any of the ordered extents had an error, just return it to user
2224 	 * space, so that the application knows some writes didn't succeed and
2225 	 * can take proper action (retry for e.g.). Blindly committing the
2226 	 * transaction in this case, would fool userspace that everything was
2227 	 * successful. And we also want to make sure our log doesn't contain
2228 	 * file extent items pointing to extents that weren't fully written to -
2229 	 * just like in the non fast fsync path, where we check for the ordered
2230 	 * operation's error flag before writing to the log tree and return -EIO
2231 	 * if any of them had this flag set (btrfs_wait_ordered_range) -
2232 	 * therefore we need to check for errors in the ordered operations,
2233 	 * which are indicated by ctx.io_err.
2234 	 */
2235 	if (ctx.io_err) {
2236 		btrfs_end_transaction(trans);
2237 		ret = ctx.io_err;
2238 		goto out;
2239 	}
2240 
2241 	if (ret != BTRFS_NO_LOG_SYNC) {
2242 		if (!ret) {
2243 			ret = btrfs_sync_log(trans, root, &ctx);
2244 			if (!ret) {
2245 				ret = btrfs_end_transaction(trans);
2246 				goto out;
2247 			}
2248 		}
2249 		ret = btrfs_commit_transaction(trans);
2250 	} else {
2251 		ret = btrfs_end_transaction(trans);
2252 	}
2253 out:
2254 	ASSERT(list_empty(&ctx.list));
2255 	err = file_check_and_advance_wb_err(file);
2256 	if (!ret)
2257 		ret = err;
2258 	return ret > 0 ? -EIO : ret;
2259 }
2260 
2261 static const struct vm_operations_struct btrfs_file_vm_ops = {
2262 	.fault		= filemap_fault,
2263 	.map_pages	= filemap_map_pages,
2264 	.page_mkwrite	= btrfs_page_mkwrite,
2265 };
2266 
btrfs_file_mmap(struct file * filp,struct vm_area_struct * vma)2267 static int btrfs_file_mmap(struct file	*filp, struct vm_area_struct *vma)
2268 {
2269 	struct address_space *mapping = filp->f_mapping;
2270 
2271 	if (!mapping->a_ops->readpage)
2272 		return -ENOEXEC;
2273 
2274 	file_accessed(filp);
2275 	vma->vm_ops = &btrfs_file_vm_ops;
2276 
2277 	return 0;
2278 }
2279 
hole_mergeable(struct btrfs_inode * inode,struct extent_buffer * leaf,int slot,u64 start,u64 end)2280 static int hole_mergeable(struct btrfs_inode *inode, struct extent_buffer *leaf,
2281 			  int slot, u64 start, u64 end)
2282 {
2283 	struct btrfs_file_extent_item *fi;
2284 	struct btrfs_key key;
2285 
2286 	if (slot < 0 || slot >= btrfs_header_nritems(leaf))
2287 		return 0;
2288 
2289 	btrfs_item_key_to_cpu(leaf, &key, slot);
2290 	if (key.objectid != btrfs_ino(inode) ||
2291 	    key.type != BTRFS_EXTENT_DATA_KEY)
2292 		return 0;
2293 
2294 	fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
2295 
2296 	if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2297 		return 0;
2298 
2299 	if (btrfs_file_extent_disk_bytenr(leaf, fi))
2300 		return 0;
2301 
2302 	if (key.offset == end)
2303 		return 1;
2304 	if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start)
2305 		return 1;
2306 	return 0;
2307 }
2308 
fill_holes(struct btrfs_trans_handle * trans,struct btrfs_inode * inode,struct btrfs_path * path,u64 offset,u64 end)2309 static int fill_holes(struct btrfs_trans_handle *trans,
2310 		struct btrfs_inode *inode,
2311 		struct btrfs_path *path, u64 offset, u64 end)
2312 {
2313 	struct btrfs_fs_info *fs_info = trans->fs_info;
2314 	struct btrfs_root *root = inode->root;
2315 	struct extent_buffer *leaf;
2316 	struct btrfs_file_extent_item *fi;
2317 	struct extent_map *hole_em;
2318 	struct extent_map_tree *em_tree = &inode->extent_tree;
2319 	struct btrfs_key key;
2320 	int ret;
2321 
2322 	if (btrfs_fs_incompat(fs_info, NO_HOLES))
2323 		goto out;
2324 
2325 	key.objectid = btrfs_ino(inode);
2326 	key.type = BTRFS_EXTENT_DATA_KEY;
2327 	key.offset = offset;
2328 
2329 	ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2330 	if (ret <= 0) {
2331 		/*
2332 		 * We should have dropped this offset, so if we find it then
2333 		 * something has gone horribly wrong.
2334 		 */
2335 		if (ret == 0)
2336 			ret = -EINVAL;
2337 		return ret;
2338 	}
2339 
2340 	leaf = path->nodes[0];
2341 	if (hole_mergeable(inode, leaf, path->slots[0] - 1, offset, end)) {
2342 		u64 num_bytes;
2343 
2344 		path->slots[0]--;
2345 		fi = btrfs_item_ptr(leaf, path->slots[0],
2346 				    struct btrfs_file_extent_item);
2347 		num_bytes = btrfs_file_extent_num_bytes(leaf, fi) +
2348 			end - offset;
2349 		btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2350 		btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2351 		btrfs_set_file_extent_offset(leaf, fi, 0);
2352 		btrfs_mark_buffer_dirty(leaf);
2353 		goto out;
2354 	}
2355 
2356 	if (hole_mergeable(inode, leaf, path->slots[0], offset, end)) {
2357 		u64 num_bytes;
2358 
2359 		key.offset = offset;
2360 		btrfs_set_item_key_safe(fs_info, path, &key);
2361 		fi = btrfs_item_ptr(leaf, path->slots[0],
2362 				    struct btrfs_file_extent_item);
2363 		num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
2364 			offset;
2365 		btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2366 		btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2367 		btrfs_set_file_extent_offset(leaf, fi, 0);
2368 		btrfs_mark_buffer_dirty(leaf);
2369 		goto out;
2370 	}
2371 	btrfs_release_path(path);
2372 
2373 	ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode),
2374 			offset, 0, 0, end - offset, 0, end - offset, 0, 0, 0);
2375 	if (ret)
2376 		return ret;
2377 
2378 out:
2379 	btrfs_release_path(path);
2380 
2381 	hole_em = alloc_extent_map();
2382 	if (!hole_em) {
2383 		btrfs_drop_extent_cache(inode, offset, end - 1, 0);
2384 		set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags);
2385 	} else {
2386 		hole_em->start = offset;
2387 		hole_em->len = end - offset;
2388 		hole_em->ram_bytes = hole_em->len;
2389 		hole_em->orig_start = offset;
2390 
2391 		hole_em->block_start = EXTENT_MAP_HOLE;
2392 		hole_em->block_len = 0;
2393 		hole_em->orig_block_len = 0;
2394 		hole_em->bdev = fs_info->fs_devices->latest_bdev;
2395 		hole_em->compress_type = BTRFS_COMPRESS_NONE;
2396 		hole_em->generation = trans->transid;
2397 
2398 		do {
2399 			btrfs_drop_extent_cache(inode, offset, end - 1, 0);
2400 			write_lock(&em_tree->lock);
2401 			ret = add_extent_mapping(em_tree, hole_em, 1);
2402 			write_unlock(&em_tree->lock);
2403 		} while (ret == -EEXIST);
2404 		free_extent_map(hole_em);
2405 		if (ret)
2406 			set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2407 					&inode->runtime_flags);
2408 	}
2409 
2410 	return 0;
2411 }
2412 
2413 /*
2414  * Find a hole extent on given inode and change start/len to the end of hole
2415  * extent.(hole/vacuum extent whose em->start <= start &&
2416  *	   em->start + em->len > start)
2417  * When a hole extent is found, return 1 and modify start/len.
2418  */
find_first_non_hole(struct inode * inode,u64 * start,u64 * len)2419 static int find_first_non_hole(struct inode *inode, u64 *start, u64 *len)
2420 {
2421 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2422 	struct extent_map *em;
2423 	int ret = 0;
2424 
2425 	em = btrfs_get_extent(BTRFS_I(inode), NULL, 0,
2426 			      round_down(*start, fs_info->sectorsize),
2427 			      round_up(*len, fs_info->sectorsize), 0);
2428 	if (IS_ERR(em))
2429 		return PTR_ERR(em);
2430 
2431 	/* Hole or vacuum extent(only exists in no-hole mode) */
2432 	if (em->block_start == EXTENT_MAP_HOLE) {
2433 		ret = 1;
2434 		*len = em->start + em->len > *start + *len ?
2435 		       0 : *start + *len - em->start - em->len;
2436 		*start = em->start + em->len;
2437 	}
2438 	free_extent_map(em);
2439 	return ret;
2440 }
2441 
btrfs_punch_hole_lock_range(struct inode * inode,const u64 lockstart,const u64 lockend,struct extent_state ** cached_state)2442 static int btrfs_punch_hole_lock_range(struct inode *inode,
2443 				       const u64 lockstart,
2444 				       const u64 lockend,
2445 				       struct extent_state **cached_state)
2446 {
2447 	while (1) {
2448 		struct btrfs_ordered_extent *ordered;
2449 		int ret;
2450 
2451 		truncate_pagecache_range(inode, lockstart, lockend);
2452 
2453 		lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2454 				 cached_state);
2455 		ordered = btrfs_lookup_first_ordered_extent(inode, lockend);
2456 
2457 		/*
2458 		 * We need to make sure we have no ordered extents in this range
2459 		 * and nobody raced in and read a page in this range, if we did
2460 		 * we need to try again.
2461 		 */
2462 		if ((!ordered ||
2463 		    (ordered->file_offset + ordered->len <= lockstart ||
2464 		     ordered->file_offset > lockend)) &&
2465 		     !filemap_range_has_page(inode->i_mapping,
2466 					     lockstart, lockend)) {
2467 			if (ordered)
2468 				btrfs_put_ordered_extent(ordered);
2469 			break;
2470 		}
2471 		if (ordered)
2472 			btrfs_put_ordered_extent(ordered);
2473 		unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
2474 				     lockend, cached_state);
2475 		ret = btrfs_wait_ordered_range(inode, lockstart,
2476 					       lockend - lockstart + 1);
2477 		if (ret)
2478 			return ret;
2479 	}
2480 	return 0;
2481 }
2482 
btrfs_punch_hole(struct inode * inode,loff_t offset,loff_t len)2483 static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
2484 {
2485 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2486 	struct btrfs_root *root = BTRFS_I(inode)->root;
2487 	struct extent_state *cached_state = NULL;
2488 	struct btrfs_path *path;
2489 	struct btrfs_block_rsv *rsv;
2490 	struct btrfs_trans_handle *trans;
2491 	u64 lockstart;
2492 	u64 lockend;
2493 	u64 tail_start;
2494 	u64 tail_len;
2495 	u64 orig_start = offset;
2496 	u64 cur_offset;
2497 	u64 min_size = btrfs_calc_trans_metadata_size(fs_info, 1);
2498 	u64 drop_end;
2499 	int ret = 0;
2500 	int err = 0;
2501 	unsigned int rsv_count;
2502 	bool same_block;
2503 	bool no_holes = btrfs_fs_incompat(fs_info, NO_HOLES);
2504 	u64 ino_size;
2505 	bool truncated_block = false;
2506 	bool updated_inode = false;
2507 
2508 	ret = btrfs_wait_ordered_range(inode, offset, len);
2509 	if (ret)
2510 		return ret;
2511 
2512 	inode_lock(inode);
2513 	ino_size = round_up(inode->i_size, fs_info->sectorsize);
2514 	ret = find_first_non_hole(inode, &offset, &len);
2515 	if (ret < 0)
2516 		goto out_only_mutex;
2517 	if (ret && !len) {
2518 		/* Already in a large hole */
2519 		ret = 0;
2520 		goto out_only_mutex;
2521 	}
2522 
2523 	lockstart = round_up(offset, btrfs_inode_sectorsize(inode));
2524 	lockend = round_down(offset + len,
2525 			     btrfs_inode_sectorsize(inode)) - 1;
2526 	same_block = (BTRFS_BYTES_TO_BLKS(fs_info, offset))
2527 		== (BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1));
2528 	/*
2529 	 * We needn't truncate any block which is beyond the end of the file
2530 	 * because we are sure there is no data there.
2531 	 */
2532 	/*
2533 	 * Only do this if we are in the same block and we aren't doing the
2534 	 * entire block.
2535 	 */
2536 	if (same_block && len < fs_info->sectorsize) {
2537 		if (offset < ino_size) {
2538 			truncated_block = true;
2539 			ret = btrfs_truncate_block(inode, offset, len, 0);
2540 		} else {
2541 			ret = 0;
2542 		}
2543 		goto out_only_mutex;
2544 	}
2545 
2546 	/* zero back part of the first block */
2547 	if (offset < ino_size) {
2548 		truncated_block = true;
2549 		ret = btrfs_truncate_block(inode, offset, 0, 0);
2550 		if (ret) {
2551 			inode_unlock(inode);
2552 			return ret;
2553 		}
2554 	}
2555 
2556 	/* Check the aligned pages after the first unaligned page,
2557 	 * if offset != orig_start, which means the first unaligned page
2558 	 * including several following pages are already in holes,
2559 	 * the extra check can be skipped */
2560 	if (offset == orig_start) {
2561 		/* after truncate page, check hole again */
2562 		len = offset + len - lockstart;
2563 		offset = lockstart;
2564 		ret = find_first_non_hole(inode, &offset, &len);
2565 		if (ret < 0)
2566 			goto out_only_mutex;
2567 		if (ret && !len) {
2568 			ret = 0;
2569 			goto out_only_mutex;
2570 		}
2571 		lockstart = offset;
2572 	}
2573 
2574 	/* Check the tail unaligned part is in a hole */
2575 	tail_start = lockend + 1;
2576 	tail_len = offset + len - tail_start;
2577 	if (tail_len) {
2578 		ret = find_first_non_hole(inode, &tail_start, &tail_len);
2579 		if (unlikely(ret < 0))
2580 			goto out_only_mutex;
2581 		if (!ret) {
2582 			/* zero the front end of the last page */
2583 			if (tail_start + tail_len < ino_size) {
2584 				truncated_block = true;
2585 				ret = btrfs_truncate_block(inode,
2586 							tail_start + tail_len,
2587 							0, 1);
2588 				if (ret)
2589 					goto out_only_mutex;
2590 			}
2591 		}
2592 	}
2593 
2594 	if (lockend < lockstart) {
2595 		ret = 0;
2596 		goto out_only_mutex;
2597 	}
2598 
2599 	ret = btrfs_punch_hole_lock_range(inode, lockstart, lockend,
2600 					  &cached_state);
2601 	if (ret)
2602 		goto out_only_mutex;
2603 
2604 	path = btrfs_alloc_path();
2605 	if (!path) {
2606 		ret = -ENOMEM;
2607 		goto out;
2608 	}
2609 
2610 	rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
2611 	if (!rsv) {
2612 		ret = -ENOMEM;
2613 		goto out_free;
2614 	}
2615 	rsv->size = btrfs_calc_trans_metadata_size(fs_info, 1);
2616 	rsv->failfast = 1;
2617 
2618 	/*
2619 	 * 1 - update the inode
2620 	 * 1 - removing the extents in the range
2621 	 * 1 - adding the hole extent if no_holes isn't set
2622 	 */
2623 	rsv_count = no_holes ? 2 : 3;
2624 	trans = btrfs_start_transaction(root, rsv_count);
2625 	if (IS_ERR(trans)) {
2626 		err = PTR_ERR(trans);
2627 		goto out_free;
2628 	}
2629 
2630 	ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
2631 				      min_size, 0);
2632 	BUG_ON(ret);
2633 	trans->block_rsv = rsv;
2634 
2635 	cur_offset = lockstart;
2636 	len = lockend - cur_offset;
2637 	while (cur_offset < lockend) {
2638 		ret = __btrfs_drop_extents(trans, root, inode, path,
2639 					   cur_offset, lockend + 1,
2640 					   &drop_end, 1, 0, 0, NULL);
2641 		if (ret != -ENOSPC)
2642 			break;
2643 
2644 		trans->block_rsv = &fs_info->trans_block_rsv;
2645 
2646 		if (cur_offset < drop_end && cur_offset < ino_size) {
2647 			ret = fill_holes(trans, BTRFS_I(inode), path,
2648 					cur_offset, drop_end);
2649 			if (ret) {
2650 				/*
2651 				 * If we failed then we didn't insert our hole
2652 				 * entries for the area we dropped, so now the
2653 				 * fs is corrupted, so we must abort the
2654 				 * transaction.
2655 				 */
2656 				btrfs_abort_transaction(trans, ret);
2657 				err = ret;
2658 				break;
2659 			}
2660 		}
2661 
2662 		cur_offset = drop_end;
2663 
2664 		ret = btrfs_update_inode(trans, root, inode);
2665 		if (ret) {
2666 			err = ret;
2667 			break;
2668 		}
2669 
2670 		btrfs_end_transaction(trans);
2671 		btrfs_btree_balance_dirty(fs_info);
2672 
2673 		trans = btrfs_start_transaction(root, rsv_count);
2674 		if (IS_ERR(trans)) {
2675 			ret = PTR_ERR(trans);
2676 			trans = NULL;
2677 			break;
2678 		}
2679 
2680 		ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
2681 					      rsv, min_size, 0);
2682 		BUG_ON(ret);	/* shouldn't happen */
2683 		trans->block_rsv = rsv;
2684 
2685 		ret = find_first_non_hole(inode, &cur_offset, &len);
2686 		if (unlikely(ret < 0))
2687 			break;
2688 		if (ret && !len) {
2689 			ret = 0;
2690 			break;
2691 		}
2692 	}
2693 
2694 	if (ret) {
2695 		err = ret;
2696 		goto out_trans;
2697 	}
2698 
2699 	trans->block_rsv = &fs_info->trans_block_rsv;
2700 	/*
2701 	 * If we are using the NO_HOLES feature we might have had already an
2702 	 * hole that overlaps a part of the region [lockstart, lockend] and
2703 	 * ends at (or beyond) lockend. Since we have no file extent items to
2704 	 * represent holes, drop_end can be less than lockend and so we must
2705 	 * make sure we have an extent map representing the existing hole (the
2706 	 * call to __btrfs_drop_extents() might have dropped the existing extent
2707 	 * map representing the existing hole), otherwise the fast fsync path
2708 	 * will not record the existence of the hole region
2709 	 * [existing_hole_start, lockend].
2710 	 */
2711 	if (drop_end <= lockend)
2712 		drop_end = lockend + 1;
2713 	/*
2714 	 * Don't insert file hole extent item if it's for a range beyond eof
2715 	 * (because it's useless) or if it represents a 0 bytes range (when
2716 	 * cur_offset == drop_end).
2717 	 */
2718 	if (cur_offset < ino_size && cur_offset < drop_end) {
2719 		ret = fill_holes(trans, BTRFS_I(inode), path,
2720 				cur_offset, drop_end);
2721 		if (ret) {
2722 			/* Same comment as above. */
2723 			btrfs_abort_transaction(trans, ret);
2724 			err = ret;
2725 			goto out_trans;
2726 		}
2727 	}
2728 
2729 out_trans:
2730 	if (!trans)
2731 		goto out_free;
2732 
2733 	inode_inc_iversion(inode);
2734 	inode->i_mtime = inode->i_ctime = current_time(inode);
2735 
2736 	trans->block_rsv = &fs_info->trans_block_rsv;
2737 	ret = btrfs_update_inode(trans, root, inode);
2738 	updated_inode = true;
2739 	btrfs_end_transaction(trans);
2740 	btrfs_btree_balance_dirty(fs_info);
2741 out_free:
2742 	btrfs_free_path(path);
2743 	btrfs_free_block_rsv(fs_info, rsv);
2744 out:
2745 	unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2746 			     &cached_state);
2747 out_only_mutex:
2748 	if (!updated_inode && truncated_block && !ret && !err) {
2749 		/*
2750 		 * If we only end up zeroing part of a page, we still need to
2751 		 * update the inode item, so that all the time fields are
2752 		 * updated as well as the necessary btrfs inode in memory fields
2753 		 * for detecting, at fsync time, if the inode isn't yet in the
2754 		 * log tree or it's there but not up to date.
2755 		 */
2756 		struct timespec64 now = current_time(inode);
2757 
2758 		inode_inc_iversion(inode);
2759 		inode->i_mtime = now;
2760 		inode->i_ctime = now;
2761 		trans = btrfs_start_transaction(root, 1);
2762 		if (IS_ERR(trans)) {
2763 			err = PTR_ERR(trans);
2764 		} else {
2765 			err = btrfs_update_inode(trans, root, inode);
2766 			ret = btrfs_end_transaction(trans);
2767 		}
2768 	}
2769 	inode_unlock(inode);
2770 	if (ret && !err)
2771 		err = ret;
2772 	return err;
2773 }
2774 
2775 /* Helper structure to record which range is already reserved */
2776 struct falloc_range {
2777 	struct list_head list;
2778 	u64 start;
2779 	u64 len;
2780 };
2781 
2782 /*
2783  * Helper function to add falloc range
2784  *
2785  * Caller should have locked the larger range of extent containing
2786  * [start, len)
2787  */
add_falloc_range(struct list_head * head,u64 start,u64 len)2788 static int add_falloc_range(struct list_head *head, u64 start, u64 len)
2789 {
2790 	struct falloc_range *prev = NULL;
2791 	struct falloc_range *range = NULL;
2792 
2793 	if (list_empty(head))
2794 		goto insert;
2795 
2796 	/*
2797 	 * As fallocate iterate by bytenr order, we only need to check
2798 	 * the last range.
2799 	 */
2800 	prev = list_entry(head->prev, struct falloc_range, list);
2801 	if (prev->start + prev->len == start) {
2802 		prev->len += len;
2803 		return 0;
2804 	}
2805 insert:
2806 	range = kmalloc(sizeof(*range), GFP_KERNEL);
2807 	if (!range)
2808 		return -ENOMEM;
2809 	range->start = start;
2810 	range->len = len;
2811 	list_add_tail(&range->list, head);
2812 	return 0;
2813 }
2814 
btrfs_fallocate_update_isize(struct inode * inode,const u64 end,const int mode)2815 static int btrfs_fallocate_update_isize(struct inode *inode,
2816 					const u64 end,
2817 					const int mode)
2818 {
2819 	struct btrfs_trans_handle *trans;
2820 	struct btrfs_root *root = BTRFS_I(inode)->root;
2821 	int ret;
2822 	int ret2;
2823 
2824 	if (mode & FALLOC_FL_KEEP_SIZE || end <= i_size_read(inode))
2825 		return 0;
2826 
2827 	trans = btrfs_start_transaction(root, 1);
2828 	if (IS_ERR(trans))
2829 		return PTR_ERR(trans);
2830 
2831 	inode->i_ctime = current_time(inode);
2832 	i_size_write(inode, end);
2833 	btrfs_ordered_update_i_size(inode, end, NULL);
2834 	ret = btrfs_update_inode(trans, root, inode);
2835 	ret2 = btrfs_end_transaction(trans);
2836 
2837 	return ret ? ret : ret2;
2838 }
2839 
2840 enum {
2841 	RANGE_BOUNDARY_WRITTEN_EXTENT = 0,
2842 	RANGE_BOUNDARY_PREALLOC_EXTENT = 1,
2843 	RANGE_BOUNDARY_HOLE = 2,
2844 };
2845 
btrfs_zero_range_check_range_boundary(struct inode * inode,u64 offset)2846 static int btrfs_zero_range_check_range_boundary(struct inode *inode,
2847 						 u64 offset)
2848 {
2849 	const u64 sectorsize = btrfs_inode_sectorsize(inode);
2850 	struct extent_map *em;
2851 	int ret;
2852 
2853 	offset = round_down(offset, sectorsize);
2854 	em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, offset, sectorsize, 0);
2855 	if (IS_ERR(em))
2856 		return PTR_ERR(em);
2857 
2858 	if (em->block_start == EXTENT_MAP_HOLE)
2859 		ret = RANGE_BOUNDARY_HOLE;
2860 	else if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2861 		ret = RANGE_BOUNDARY_PREALLOC_EXTENT;
2862 	else
2863 		ret = RANGE_BOUNDARY_WRITTEN_EXTENT;
2864 
2865 	free_extent_map(em);
2866 	return ret;
2867 }
2868 
btrfs_zero_range(struct inode * inode,loff_t offset,loff_t len,const int mode)2869 static int btrfs_zero_range(struct inode *inode,
2870 			    loff_t offset,
2871 			    loff_t len,
2872 			    const int mode)
2873 {
2874 	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2875 	struct extent_map *em;
2876 	struct extent_changeset *data_reserved = NULL;
2877 	int ret;
2878 	u64 alloc_hint = 0;
2879 	const u64 sectorsize = btrfs_inode_sectorsize(inode);
2880 	u64 alloc_start = round_down(offset, sectorsize);
2881 	u64 alloc_end = round_up(offset + len, sectorsize);
2882 	u64 bytes_to_reserve = 0;
2883 	bool space_reserved = false;
2884 
2885 	inode_dio_wait(inode);
2886 
2887 	em = btrfs_get_extent(BTRFS_I(inode), NULL, 0,
2888 			      alloc_start, alloc_end - alloc_start, 0);
2889 	if (IS_ERR(em)) {
2890 		ret = PTR_ERR(em);
2891 		goto out;
2892 	}
2893 
2894 	/*
2895 	 * Avoid hole punching and extent allocation for some cases. More cases
2896 	 * could be considered, but these are unlikely common and we keep things
2897 	 * as simple as possible for now. Also, intentionally, if the target
2898 	 * range contains one or more prealloc extents together with regular
2899 	 * extents and holes, we drop all the existing extents and allocate a
2900 	 * new prealloc extent, so that we get a larger contiguous disk extent.
2901 	 */
2902 	if (em->start <= alloc_start &&
2903 	    test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
2904 		const u64 em_end = em->start + em->len;
2905 
2906 		if (em_end >= offset + len) {
2907 			/*
2908 			 * The whole range is already a prealloc extent,
2909 			 * do nothing except updating the inode's i_size if
2910 			 * needed.
2911 			 */
2912 			free_extent_map(em);
2913 			ret = btrfs_fallocate_update_isize(inode, offset + len,
2914 							   mode);
2915 			goto out;
2916 		}
2917 		/*
2918 		 * Part of the range is already a prealloc extent, so operate
2919 		 * only on the remaining part of the range.
2920 		 */
2921 		alloc_start = em_end;
2922 		ASSERT(IS_ALIGNED(alloc_start, sectorsize));
2923 		len = offset + len - alloc_start;
2924 		offset = alloc_start;
2925 		alloc_hint = em->block_start + em->len;
2926 	}
2927 	free_extent_map(em);
2928 
2929 	if (BTRFS_BYTES_TO_BLKS(fs_info, offset) ==
2930 	    BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1)) {
2931 		em = btrfs_get_extent(BTRFS_I(inode), NULL, 0,
2932 				      alloc_start, sectorsize, 0);
2933 		if (IS_ERR(em)) {
2934 			ret = PTR_ERR(em);
2935 			goto out;
2936 		}
2937 
2938 		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
2939 			free_extent_map(em);
2940 			ret = btrfs_fallocate_update_isize(inode, offset + len,
2941 							   mode);
2942 			goto out;
2943 		}
2944 		if (len < sectorsize && em->block_start != EXTENT_MAP_HOLE) {
2945 			free_extent_map(em);
2946 			ret = btrfs_truncate_block(inode, offset, len, 0);
2947 			if (!ret)
2948 				ret = btrfs_fallocate_update_isize(inode,
2949 								   offset + len,
2950 								   mode);
2951 			return ret;
2952 		}
2953 		free_extent_map(em);
2954 		alloc_start = round_down(offset, sectorsize);
2955 		alloc_end = alloc_start + sectorsize;
2956 		goto reserve_space;
2957 	}
2958 
2959 	alloc_start = round_up(offset, sectorsize);
2960 	alloc_end = round_down(offset + len, sectorsize);
2961 
2962 	/*
2963 	 * For unaligned ranges, check the pages at the boundaries, they might
2964 	 * map to an extent, in which case we need to partially zero them, or
2965 	 * they might map to a hole, in which case we need our allocation range
2966 	 * to cover them.
2967 	 */
2968 	if (!IS_ALIGNED(offset, sectorsize)) {
2969 		ret = btrfs_zero_range_check_range_boundary(inode, offset);
2970 		if (ret < 0)
2971 			goto out;
2972 		if (ret == RANGE_BOUNDARY_HOLE) {
2973 			alloc_start = round_down(offset, sectorsize);
2974 			ret = 0;
2975 		} else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
2976 			ret = btrfs_truncate_block(inode, offset, 0, 0);
2977 			if (ret)
2978 				goto out;
2979 		} else {
2980 			ret = 0;
2981 		}
2982 	}
2983 
2984 	if (!IS_ALIGNED(offset + len, sectorsize)) {
2985 		ret = btrfs_zero_range_check_range_boundary(inode,
2986 							    offset + len);
2987 		if (ret < 0)
2988 			goto out;
2989 		if (ret == RANGE_BOUNDARY_HOLE) {
2990 			alloc_end = round_up(offset + len, sectorsize);
2991 			ret = 0;
2992 		} else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
2993 			ret = btrfs_truncate_block(inode, offset + len, 0, 1);
2994 			if (ret)
2995 				goto out;
2996 		} else {
2997 			ret = 0;
2998 		}
2999 	}
3000 
3001 reserve_space:
3002 	if (alloc_start < alloc_end) {
3003 		struct extent_state *cached_state = NULL;
3004 		const u64 lockstart = alloc_start;
3005 		const u64 lockend = alloc_end - 1;
3006 
3007 		bytes_to_reserve = alloc_end - alloc_start;
3008 		ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
3009 						      bytes_to_reserve);
3010 		if (ret < 0)
3011 			goto out;
3012 		space_reserved = true;
3013 		ret = btrfs_punch_hole_lock_range(inode, lockstart, lockend,
3014 						  &cached_state);
3015 		if (ret)
3016 			goto out;
3017 		ret = btrfs_qgroup_reserve_data(inode, &data_reserved,
3018 						alloc_start, bytes_to_reserve);
3019 		if (ret) {
3020 			unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
3021 					     lockend, &cached_state);
3022 			goto out;
3023 		}
3024 		ret = btrfs_prealloc_file_range(inode, mode, alloc_start,
3025 						alloc_end - alloc_start,
3026 						i_blocksize(inode),
3027 						offset + len, &alloc_hint);
3028 		unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
3029 				     lockend, &cached_state);
3030 		/* btrfs_prealloc_file_range releases reserved space on error */
3031 		if (ret) {
3032 			space_reserved = false;
3033 			goto out;
3034 		}
3035 	}
3036 	ret = btrfs_fallocate_update_isize(inode, offset + len, mode);
3037  out:
3038 	if (ret && space_reserved)
3039 		btrfs_free_reserved_data_space(inode, data_reserved,
3040 					       alloc_start, bytes_to_reserve);
3041 	extent_changeset_free(data_reserved);
3042 
3043 	return ret;
3044 }
3045 
btrfs_fallocate(struct file * file,int mode,loff_t offset,loff_t len)3046 static long btrfs_fallocate(struct file *file, int mode,
3047 			    loff_t offset, loff_t len)
3048 {
3049 	struct inode *inode = file_inode(file);
3050 	struct extent_state *cached_state = NULL;
3051 	struct extent_changeset *data_reserved = NULL;
3052 	struct falloc_range *range;
3053 	struct falloc_range *tmp;
3054 	struct list_head reserve_list;
3055 	u64 cur_offset;
3056 	u64 last_byte;
3057 	u64 alloc_start;
3058 	u64 alloc_end;
3059 	u64 alloc_hint = 0;
3060 	u64 locked_end;
3061 	u64 actual_end = 0;
3062 	struct extent_map *em;
3063 	int blocksize = btrfs_inode_sectorsize(inode);
3064 	int ret;
3065 
3066 	alloc_start = round_down(offset, blocksize);
3067 	alloc_end = round_up(offset + len, blocksize);
3068 	cur_offset = alloc_start;
3069 
3070 	/* Make sure we aren't being give some crap mode */
3071 	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
3072 		     FALLOC_FL_ZERO_RANGE))
3073 		return -EOPNOTSUPP;
3074 
3075 	if (mode & FALLOC_FL_PUNCH_HOLE)
3076 		return btrfs_punch_hole(inode, offset, len);
3077 
3078 	/*
3079 	 * Only trigger disk allocation, don't trigger qgroup reserve
3080 	 *
3081 	 * For qgroup space, it will be checked later.
3082 	 */
3083 	if (!(mode & FALLOC_FL_ZERO_RANGE)) {
3084 		ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
3085 						      alloc_end - alloc_start);
3086 		if (ret < 0)
3087 			return ret;
3088 	}
3089 
3090 	inode_lock(inode);
3091 
3092 	if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) {
3093 		ret = inode_newsize_ok(inode, offset + len);
3094 		if (ret)
3095 			goto out;
3096 	}
3097 
3098 	/*
3099 	 * TODO: Move these two operations after we have checked
3100 	 * accurate reserved space, or fallocate can still fail but
3101 	 * with page truncated or size expanded.
3102 	 *
3103 	 * But that's a minor problem and won't do much harm BTW.
3104 	 */
3105 	if (alloc_start > inode->i_size) {
3106 		ret = btrfs_cont_expand(inode, i_size_read(inode),
3107 					alloc_start);
3108 		if (ret)
3109 			goto out;
3110 	} else if (offset + len > inode->i_size) {
3111 		/*
3112 		 * If we are fallocating from the end of the file onward we
3113 		 * need to zero out the end of the block if i_size lands in the
3114 		 * middle of a block.
3115 		 */
3116 		ret = btrfs_truncate_block(inode, inode->i_size, 0, 0);
3117 		if (ret)
3118 			goto out;
3119 	}
3120 
3121 	/*
3122 	 * wait for ordered IO before we have any locks.  We'll loop again
3123 	 * below with the locks held.
3124 	 */
3125 	ret = btrfs_wait_ordered_range(inode, alloc_start,
3126 				       alloc_end - alloc_start);
3127 	if (ret)
3128 		goto out;
3129 
3130 	if (mode & FALLOC_FL_ZERO_RANGE) {
3131 		ret = btrfs_zero_range(inode, offset, len, mode);
3132 		inode_unlock(inode);
3133 		return ret;
3134 	}
3135 
3136 	locked_end = alloc_end - 1;
3137 	while (1) {
3138 		struct btrfs_ordered_extent *ordered;
3139 
3140 		/* the extent lock is ordered inside the running
3141 		 * transaction
3142 		 */
3143 		lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
3144 				 locked_end, &cached_state);
3145 		ordered = btrfs_lookup_first_ordered_extent(inode, locked_end);
3146 
3147 		if (ordered &&
3148 		    ordered->file_offset + ordered->len > alloc_start &&
3149 		    ordered->file_offset < alloc_end) {
3150 			btrfs_put_ordered_extent(ordered);
3151 			unlock_extent_cached(&BTRFS_I(inode)->io_tree,
3152 					     alloc_start, locked_end,
3153 					     &cached_state);
3154 			/*
3155 			 * we can't wait on the range with the transaction
3156 			 * running or with the extent lock held
3157 			 */
3158 			ret = btrfs_wait_ordered_range(inode, alloc_start,
3159 						       alloc_end - alloc_start);
3160 			if (ret)
3161 				goto out;
3162 		} else {
3163 			if (ordered)
3164 				btrfs_put_ordered_extent(ordered);
3165 			break;
3166 		}
3167 	}
3168 
3169 	/* First, check if we exceed the qgroup limit */
3170 	INIT_LIST_HEAD(&reserve_list);
3171 	while (cur_offset < alloc_end) {
3172 		em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, cur_offset,
3173 				      alloc_end - cur_offset, 0);
3174 		if (IS_ERR(em)) {
3175 			ret = PTR_ERR(em);
3176 			break;
3177 		}
3178 		last_byte = min(extent_map_end(em), alloc_end);
3179 		actual_end = min_t(u64, extent_map_end(em), offset + len);
3180 		last_byte = ALIGN(last_byte, blocksize);
3181 		if (em->block_start == EXTENT_MAP_HOLE ||
3182 		    (cur_offset >= inode->i_size &&
3183 		     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
3184 			ret = add_falloc_range(&reserve_list, cur_offset,
3185 					       last_byte - cur_offset);
3186 			if (ret < 0) {
3187 				free_extent_map(em);
3188 				break;
3189 			}
3190 			ret = btrfs_qgroup_reserve_data(inode, &data_reserved,
3191 					cur_offset, last_byte - cur_offset);
3192 			if (ret < 0) {
3193 				cur_offset = last_byte;
3194 				free_extent_map(em);
3195 				break;
3196 			}
3197 		} else {
3198 			/*
3199 			 * Do not need to reserve unwritten extent for this
3200 			 * range, free reserved data space first, otherwise
3201 			 * it'll result in false ENOSPC error.
3202 			 */
3203 			btrfs_free_reserved_data_space(inode, data_reserved,
3204 					cur_offset, last_byte - cur_offset);
3205 		}
3206 		free_extent_map(em);
3207 		cur_offset = last_byte;
3208 	}
3209 
3210 	/*
3211 	 * If ret is still 0, means we're OK to fallocate.
3212 	 * Or just cleanup the list and exit.
3213 	 */
3214 	list_for_each_entry_safe(range, tmp, &reserve_list, list) {
3215 		if (!ret)
3216 			ret = btrfs_prealloc_file_range(inode, mode,
3217 					range->start,
3218 					range->len, i_blocksize(inode),
3219 					offset + len, &alloc_hint);
3220 		else
3221 			btrfs_free_reserved_data_space(inode,
3222 					data_reserved, range->start,
3223 					range->len);
3224 		list_del(&range->list);
3225 		kfree(range);
3226 	}
3227 	if (ret < 0)
3228 		goto out_unlock;
3229 
3230 	/*
3231 	 * We didn't need to allocate any more space, but we still extended the
3232 	 * size of the file so we need to update i_size and the inode item.
3233 	 */
3234 	ret = btrfs_fallocate_update_isize(inode, actual_end, mode);
3235 out_unlock:
3236 	unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
3237 			     &cached_state);
3238 out:
3239 	inode_unlock(inode);
3240 	/* Let go of our reservation. */
3241 	if (ret != 0 && !(mode & FALLOC_FL_ZERO_RANGE))
3242 		btrfs_free_reserved_data_space(inode, data_reserved,
3243 				cur_offset, alloc_end - cur_offset);
3244 	extent_changeset_free(data_reserved);
3245 	return ret;
3246 }
3247 
find_desired_extent(struct inode * inode,loff_t * offset,int whence)3248 static int find_desired_extent(struct inode *inode, loff_t *offset, int whence)
3249 {
3250 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3251 	struct extent_map *em = NULL;
3252 	struct extent_state *cached_state = NULL;
3253 	u64 lockstart;
3254 	u64 lockend;
3255 	u64 start;
3256 	u64 len;
3257 	int ret = 0;
3258 
3259 	if (inode->i_size == 0)
3260 		return -ENXIO;
3261 
3262 	/*
3263 	 * *offset can be negative, in this case we start finding DATA/HOLE from
3264 	 * the very start of the file.
3265 	 */
3266 	start = max_t(loff_t, 0, *offset);
3267 
3268 	lockstart = round_down(start, fs_info->sectorsize);
3269 	lockend = round_up(i_size_read(inode),
3270 			   fs_info->sectorsize);
3271 	if (lockend <= lockstart)
3272 		lockend = lockstart + fs_info->sectorsize;
3273 	lockend--;
3274 	len = lockend - lockstart + 1;
3275 
3276 	lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
3277 			 &cached_state);
3278 
3279 	while (start < inode->i_size) {
3280 		em = btrfs_get_extent_fiemap(BTRFS_I(inode), NULL, 0,
3281 				start, len, 0);
3282 		if (IS_ERR(em)) {
3283 			ret = PTR_ERR(em);
3284 			em = NULL;
3285 			break;
3286 		}
3287 
3288 		if (whence == SEEK_HOLE &&
3289 		    (em->block_start == EXTENT_MAP_HOLE ||
3290 		     test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
3291 			break;
3292 		else if (whence == SEEK_DATA &&
3293 			   (em->block_start != EXTENT_MAP_HOLE &&
3294 			    !test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
3295 			break;
3296 
3297 		start = em->start + em->len;
3298 		free_extent_map(em);
3299 		em = NULL;
3300 		cond_resched();
3301 	}
3302 	free_extent_map(em);
3303 	if (!ret) {
3304 		if (whence == SEEK_DATA && start >= inode->i_size)
3305 			ret = -ENXIO;
3306 		else
3307 			*offset = min_t(loff_t, start, inode->i_size);
3308 	}
3309 	unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
3310 			     &cached_state);
3311 	return ret;
3312 }
3313 
btrfs_file_llseek(struct file * file,loff_t offset,int whence)3314 static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
3315 {
3316 	struct inode *inode = file->f_mapping->host;
3317 	int ret;
3318 
3319 	inode_lock(inode);
3320 	switch (whence) {
3321 	case SEEK_END:
3322 	case SEEK_CUR:
3323 		offset = generic_file_llseek(file, offset, whence);
3324 		goto out;
3325 	case SEEK_DATA:
3326 	case SEEK_HOLE:
3327 		if (offset >= i_size_read(inode)) {
3328 			inode_unlock(inode);
3329 			return -ENXIO;
3330 		}
3331 
3332 		ret = find_desired_extent(inode, &offset, whence);
3333 		if (ret) {
3334 			inode_unlock(inode);
3335 			return ret;
3336 		}
3337 	}
3338 
3339 	offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
3340 out:
3341 	inode_unlock(inode);
3342 	return offset;
3343 }
3344 
btrfs_file_open(struct inode * inode,struct file * filp)3345 static int btrfs_file_open(struct inode *inode, struct file *filp)
3346 {
3347 	filp->f_mode |= FMODE_NOWAIT;
3348 	return generic_file_open(inode, filp);
3349 }
3350 
3351 const struct file_operations btrfs_file_operations = {
3352 	.llseek		= btrfs_file_llseek,
3353 	.read_iter      = generic_file_read_iter,
3354 	.splice_read	= generic_file_splice_read,
3355 	.write_iter	= btrfs_file_write_iter,
3356 	.mmap		= btrfs_file_mmap,
3357 	.open		= btrfs_file_open,
3358 	.release	= btrfs_release_file,
3359 	.fsync		= btrfs_sync_file,
3360 	.fallocate	= btrfs_fallocate,
3361 	.unlocked_ioctl	= btrfs_ioctl,
3362 #ifdef CONFIG_COMPAT
3363 	.compat_ioctl	= btrfs_compat_ioctl,
3364 #endif
3365 	.clone_file_range = btrfs_clone_file_range,
3366 	.dedupe_file_range = btrfs_dedupe_file_range,
3367 };
3368 
btrfs_auto_defrag_exit(void)3369 void __cold btrfs_auto_defrag_exit(void)
3370 {
3371 	kmem_cache_destroy(btrfs_inode_defrag_cachep);
3372 }
3373 
btrfs_auto_defrag_init(void)3374 int __init btrfs_auto_defrag_init(void)
3375 {
3376 	btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
3377 					sizeof(struct inode_defrag), 0,
3378 					SLAB_MEM_SPREAD,
3379 					NULL);
3380 	if (!btrfs_inode_defrag_cachep)
3381 		return -ENOMEM;
3382 
3383 	return 0;
3384 }
3385 
btrfs_fdatawrite_range(struct inode * inode,loff_t start,loff_t end)3386 int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end)
3387 {
3388 	int ret;
3389 
3390 	/*
3391 	 * So with compression we will find and lock a dirty page and clear the
3392 	 * first one as dirty, setup an async extent, and immediately return
3393 	 * with the entire range locked but with nobody actually marked with
3394 	 * writeback.  So we can't just filemap_write_and_wait_range() and
3395 	 * expect it to work since it will just kick off a thread to do the
3396 	 * actual work.  So we need to call filemap_fdatawrite_range _again_
3397 	 * since it will wait on the page lock, which won't be unlocked until
3398 	 * after the pages have been marked as writeback and so we're good to go
3399 	 * from there.  We have to do this otherwise we'll miss the ordered
3400 	 * extents and that results in badness.  Please Josef, do not think you
3401 	 * know better and pull this out at some point in the future, it is
3402 	 * right and you are wrong.
3403 	 */
3404 	ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
3405 	if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
3406 			     &BTRFS_I(inode)->runtime_flags))
3407 		ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
3408 
3409 	return ret;
3410 }
3411