2 * Copyright (C) 2007 Oracle. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
20 #include <linux/pagemap.h>
21 #include <linux/highmem.h>
22 #include <linux/time.h>
23 #include <linux/init.h>
24 #include <linux/string.h>
25 #include <linux/backing-dev.h>
26 #include <linux/mpage.h>
27 #include <linux/swap.h>
28 #include <linux/writeback.h>
29 #include <linux/statfs.h>
30 #include <linux/compat.h>
33 #include "transaction.h"
34 #include "btrfs_inode.h"
36 #include "print-tree.h"
42 /* simple helper to fault in pages and copy. This should go away
43 * and be replaced with calls into generic code.
45 static noinline
int btrfs_copy_from_user(loff_t pos
, int num_pages
,
47 struct page
**prepared_pages
,
48 const char __user
*buf
)
52 int offset
= pos
& (PAGE_CACHE_SIZE
- 1);
54 for (i
= 0; i
< num_pages
&& write_bytes
> 0; i
++, offset
= 0) {
55 size_t count
= min_t(size_t,
56 PAGE_CACHE_SIZE
- offset
, write_bytes
);
57 struct page
*page
= prepared_pages
[i
];
58 fault_in_pages_readable(buf
, count
);
60 /* Copy data from userspace to the current page */
62 page_fault
= __copy_from_user(page_address(page
) + offset
,
64 /* Flush processor's dcache for this page */
65 flush_dcache_page(page
);
73 return page_fault
? -EFAULT
: 0;
77 * unlocks pages after btrfs_file_write is done with them
79 static noinline
void btrfs_drop_pages(struct page
**pages
, size_t num_pages
)
82 for (i
= 0; i
< num_pages
; i
++) {
85 /* page checked is some magic around finding pages that
86 * have been modified without going through btrfs_set_page_dirty
89 ClearPageChecked(pages
[i
]);
90 unlock_page(pages
[i
]);
91 mark_page_accessed(pages
[i
]);
92 page_cache_release(pages
[i
]);
97 * after copy_from_user, pages need to be dirtied and we need to make
98 * sure holes are created between the current EOF and the start of
99 * any next extents (if required).
101 * this also makes the decision about creating an inline extent vs
102 * doing real data extents, marking pages dirty and delalloc as required.
104 static noinline
int dirty_and_release_pages(struct btrfs_trans_handle
*trans
,
105 struct btrfs_root
*root
,
114 struct inode
*inode
= fdentry(file
)->d_inode
;
117 u64 end_of_last_block
;
118 u64 end_pos
= pos
+ write_bytes
;
119 loff_t isize
= i_size_read(inode
);
121 start_pos
= pos
& ~((u64
)root
->sectorsize
- 1);
122 num_bytes
= (write_bytes
+ pos
- start_pos
+
123 root
->sectorsize
- 1) & ~((u64
)root
->sectorsize
- 1);
125 end_of_last_block
= start_pos
+ num_bytes
- 1;
126 err
= btrfs_set_extent_delalloc(inode
, start_pos
, end_of_last_block
);
130 for (i
= 0; i
< num_pages
; i
++) {
131 struct page
*p
= pages
[i
];
136 if (end_pos
> isize
) {
137 i_size_write(inode
, end_pos
);
138 /* we've only changed i_size in ram, and we haven't updated
139 * the disk i_size. There is no need to log the inode
147 * this drops all the extents in the cache that intersect the range
148 * [start, end]. Existing extents are split as required.
150 int btrfs_drop_extent_cache(struct inode
*inode
, u64 start
, u64 end
,
153 struct extent_map
*em
;
154 struct extent_map
*split
= NULL
;
155 struct extent_map
*split2
= NULL
;
156 struct extent_map_tree
*em_tree
= &BTRFS_I(inode
)->extent_tree
;
157 u64 len
= end
- start
+ 1;
163 WARN_ON(end
< start
);
164 if (end
== (u64
)-1) {
170 split
= alloc_extent_map(GFP_NOFS
);
172 split2
= alloc_extent_map(GFP_NOFS
);
174 write_lock(&em_tree
->lock
);
175 em
= lookup_extent_mapping(em_tree
, start
, len
);
177 write_unlock(&em_tree
->lock
);
181 if (skip_pinned
&& test_bit(EXTENT_FLAG_PINNED
, &em
->flags
)) {
182 if (testend
&& em
->start
+ em
->len
>= start
+ len
) {
184 write_unlock(&em_tree
->lock
);
187 start
= em
->start
+ em
->len
;
189 len
= start
+ len
- (em
->start
+ em
->len
);
191 write_unlock(&em_tree
->lock
);
194 compressed
= test_bit(EXTENT_FLAG_COMPRESSED
, &em
->flags
);
195 clear_bit(EXTENT_FLAG_PINNED
, &em
->flags
);
196 remove_extent_mapping(em_tree
, em
);
198 if (em
->block_start
< EXTENT_MAP_LAST_BYTE
&&
200 split
->start
= em
->start
;
201 split
->len
= start
- em
->start
;
202 split
->orig_start
= em
->orig_start
;
203 split
->block_start
= em
->block_start
;
206 split
->block_len
= em
->block_len
;
208 split
->block_len
= split
->len
;
210 split
->bdev
= em
->bdev
;
211 split
->flags
= flags
;
212 ret
= add_extent_mapping(em_tree
, split
);
214 free_extent_map(split
);
218 if (em
->block_start
< EXTENT_MAP_LAST_BYTE
&&
219 testend
&& em
->start
+ em
->len
> start
+ len
) {
220 u64 diff
= start
+ len
- em
->start
;
222 split
->start
= start
+ len
;
223 split
->len
= em
->start
+ em
->len
- (start
+ len
);
224 split
->bdev
= em
->bdev
;
225 split
->flags
= flags
;
228 split
->block_len
= em
->block_len
;
229 split
->block_start
= em
->block_start
;
230 split
->orig_start
= em
->orig_start
;
232 split
->block_len
= split
->len
;
233 split
->block_start
= em
->block_start
+ diff
;
234 split
->orig_start
= split
->start
;
237 ret
= add_extent_mapping(em_tree
, split
);
239 free_extent_map(split
);
242 write_unlock(&em_tree
->lock
);
246 /* once for the tree*/
250 free_extent_map(split
);
252 free_extent_map(split2
);
257 * this is very complex, but the basic idea is to drop all extents
258 * in the range start - end. hint_block is filled in with a block number
259 * that would be a good hint to the block allocator for this file.
261 * If an extent intersects the range but is not entirely inside the range
262 * it is either truncated or split. Anything entirely inside the range
263 * is deleted from the tree.
265 int btrfs_drop_extents(struct btrfs_trans_handle
*trans
, struct inode
*inode
,
266 u64 start
, u64 end
, u64
*hint_byte
, int drop_cache
)
268 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
269 struct extent_buffer
*leaf
;
270 struct btrfs_file_extent_item
*fi
;
271 struct btrfs_path
*path
;
272 struct btrfs_key key
;
273 struct btrfs_key new_key
;
274 u64 search_start
= start
;
277 u64 extent_offset
= 0;
286 btrfs_drop_extent_cache(inode
, start
, end
- 1, 0);
288 path
= btrfs_alloc_path();
294 ret
= btrfs_lookup_file_extent(trans
, root
, path
, inode
->i_ino
,
298 if (ret
> 0 && path
->slots
[0] > 0 && search_start
== start
) {
299 leaf
= path
->nodes
[0];
300 btrfs_item_key_to_cpu(leaf
, &key
, path
->slots
[0] - 1);
301 if (key
.objectid
== inode
->i_ino
&&
302 key
.type
== BTRFS_EXTENT_DATA_KEY
)
307 leaf
= path
->nodes
[0];
308 if (path
->slots
[0] >= btrfs_header_nritems(leaf
)) {
310 ret
= btrfs_next_leaf(root
, path
);
317 leaf
= path
->nodes
[0];
321 btrfs_item_key_to_cpu(leaf
, &key
, path
->slots
[0]);
322 if (key
.objectid
> inode
->i_ino
||
323 key
.type
> BTRFS_EXTENT_DATA_KEY
|| key
.offset
>= end
)
326 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
327 struct btrfs_file_extent_item
);
328 extent_type
= btrfs_file_extent_type(leaf
, fi
);
330 if (extent_type
== BTRFS_FILE_EXTENT_REG
||
331 extent_type
== BTRFS_FILE_EXTENT_PREALLOC
) {
332 disk_bytenr
= btrfs_file_extent_disk_bytenr(leaf
, fi
);
333 num_bytes
= btrfs_file_extent_disk_num_bytes(leaf
, fi
);
334 extent_offset
= btrfs_file_extent_offset(leaf
, fi
);
335 extent_end
= key
.offset
+
336 btrfs_file_extent_num_bytes(leaf
, fi
);
337 } else if (extent_type
== BTRFS_FILE_EXTENT_INLINE
) {
338 extent_end
= key
.offset
+
339 btrfs_file_extent_inline_len(leaf
, fi
);
342 extent_end
= search_start
;
345 if (extent_end
<= search_start
) {
350 search_start
= max(key
.offset
, start
);
352 btrfs_release_path(root
, path
);
357 * | - range to drop - |
358 * | -------- extent -------- |
360 if (start
> key
.offset
&& end
< extent_end
) {
362 BUG_ON(extent_type
== BTRFS_FILE_EXTENT_INLINE
);
364 memcpy(&new_key
, &key
, sizeof(new_key
));
365 new_key
.offset
= start
;
366 ret
= btrfs_duplicate_item(trans
, root
, path
,
368 if (ret
== -EAGAIN
) {
369 btrfs_release_path(root
, path
);
375 leaf
= path
->nodes
[0];
376 fi
= btrfs_item_ptr(leaf
, path
->slots
[0] - 1,
377 struct btrfs_file_extent_item
);
378 btrfs_set_file_extent_num_bytes(leaf
, fi
,
381 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
382 struct btrfs_file_extent_item
);
384 extent_offset
+= start
- key
.offset
;
385 btrfs_set_file_extent_offset(leaf
, fi
, extent_offset
);
386 btrfs_set_file_extent_num_bytes(leaf
, fi
,
388 btrfs_mark_buffer_dirty(leaf
);
390 if (disk_bytenr
> 0) {
391 ret
= btrfs_inc_extent_ref(trans
, root
,
392 disk_bytenr
, num_bytes
, 0,
393 root
->root_key
.objectid
,
395 start
- extent_offset
);
397 *hint_byte
= disk_bytenr
;
402 * | ---- range to drop ----- |
403 * | -------- extent -------- |
405 if (start
<= key
.offset
&& end
< extent_end
) {
406 BUG_ON(extent_type
== BTRFS_FILE_EXTENT_INLINE
);
408 memcpy(&new_key
, &key
, sizeof(new_key
));
409 new_key
.offset
= end
;
410 btrfs_set_item_key_safe(trans
, root
, path
, &new_key
);
412 extent_offset
+= end
- key
.offset
;
413 btrfs_set_file_extent_offset(leaf
, fi
, extent_offset
);
414 btrfs_set_file_extent_num_bytes(leaf
, fi
,
416 btrfs_mark_buffer_dirty(leaf
);
417 if (disk_bytenr
> 0) {
418 inode_sub_bytes(inode
, end
- key
.offset
);
419 *hint_byte
= disk_bytenr
;
424 search_start
= extent_end
;
426 * | ---- range to drop ----- |
427 * | -------- extent -------- |
429 if (start
> key
.offset
&& end
>= extent_end
) {
431 BUG_ON(extent_type
== BTRFS_FILE_EXTENT_INLINE
);
433 btrfs_set_file_extent_num_bytes(leaf
, fi
,
435 btrfs_mark_buffer_dirty(leaf
);
436 if (disk_bytenr
> 0) {
437 inode_sub_bytes(inode
, extent_end
- start
);
438 *hint_byte
= disk_bytenr
;
440 if (end
== extent_end
)
448 * | ---- range to drop ----- |
449 * | ------ extent ------ |
451 if (start
<= key
.offset
&& end
>= extent_end
) {
453 del_slot
= path
->slots
[0];
456 BUG_ON(del_slot
+ del_nr
!= path
->slots
[0]);
460 if (extent_type
== BTRFS_FILE_EXTENT_INLINE
) {
461 inode_sub_bytes(inode
,
462 extent_end
- key
.offset
);
463 extent_end
= ALIGN(extent_end
,
465 } else if (disk_bytenr
> 0) {
466 ret
= btrfs_free_extent(trans
, root
,
467 disk_bytenr
, num_bytes
, 0,
468 root
->root_key
.objectid
,
469 key
.objectid
, key
.offset
-
472 inode_sub_bytes(inode
,
473 extent_end
- key
.offset
);
474 *hint_byte
= disk_bytenr
;
477 if (end
== extent_end
)
480 if (path
->slots
[0] + 1 < btrfs_header_nritems(leaf
)) {
485 ret
= btrfs_del_items(trans
, root
, path
, del_slot
,
492 btrfs_release_path(root
, path
);
500 ret
= btrfs_del_items(trans
, root
, path
, del_slot
, del_nr
);
504 btrfs_free_path(path
);
508 static int extent_mergeable(struct extent_buffer
*leaf
, int slot
,
509 u64 objectid
, u64 bytenr
, u64 orig_offset
,
510 u64
*start
, u64
*end
)
512 struct btrfs_file_extent_item
*fi
;
513 struct btrfs_key key
;
516 if (slot
< 0 || slot
>= btrfs_header_nritems(leaf
))
519 btrfs_item_key_to_cpu(leaf
, &key
, slot
);
520 if (key
.objectid
!= objectid
|| key
.type
!= BTRFS_EXTENT_DATA_KEY
)
523 fi
= btrfs_item_ptr(leaf
, slot
, struct btrfs_file_extent_item
);
524 if (btrfs_file_extent_type(leaf
, fi
) != BTRFS_FILE_EXTENT_REG
||
525 btrfs_file_extent_disk_bytenr(leaf
, fi
) != bytenr
||
526 btrfs_file_extent_offset(leaf
, fi
) != key
.offset
- orig_offset
||
527 btrfs_file_extent_compression(leaf
, fi
) ||
528 btrfs_file_extent_encryption(leaf
, fi
) ||
529 btrfs_file_extent_other_encoding(leaf
, fi
))
532 extent_end
= key
.offset
+ btrfs_file_extent_num_bytes(leaf
, fi
);
533 if ((*start
&& *start
!= key
.offset
) || (*end
&& *end
!= extent_end
))
542 * Mark extent in the range start - end as written.
544 * This changes extent type from 'pre-allocated' to 'regular'. If only
545 * part of extent is marked as written, the extent will be split into
548 int btrfs_mark_extent_written(struct btrfs_trans_handle
*trans
,
549 struct inode
*inode
, u64 start
, u64 end
)
551 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
552 struct extent_buffer
*leaf
;
553 struct btrfs_path
*path
;
554 struct btrfs_file_extent_item
*fi
;
555 struct btrfs_key key
;
556 struct btrfs_key new_key
;
569 btrfs_drop_extent_cache(inode
, start
, end
- 1, 0);
571 path
= btrfs_alloc_path();
576 key
.objectid
= inode
->i_ino
;
577 key
.type
= BTRFS_EXTENT_DATA_KEY
;
580 ret
= btrfs_search_slot(trans
, root
, &key
, path
, -1, 1);
581 if (ret
> 0 && path
->slots
[0] > 0)
584 leaf
= path
->nodes
[0];
585 btrfs_item_key_to_cpu(leaf
, &key
, path
->slots
[0]);
586 BUG_ON(key
.objectid
!= inode
->i_ino
||
587 key
.type
!= BTRFS_EXTENT_DATA_KEY
);
588 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
589 struct btrfs_file_extent_item
);
590 BUG_ON(btrfs_file_extent_type(leaf
, fi
) !=
591 BTRFS_FILE_EXTENT_PREALLOC
);
592 extent_end
= key
.offset
+ btrfs_file_extent_num_bytes(leaf
, fi
);
593 BUG_ON(key
.offset
> start
|| extent_end
< end
);
595 bytenr
= btrfs_file_extent_disk_bytenr(leaf
, fi
);
596 num_bytes
= btrfs_file_extent_disk_num_bytes(leaf
, fi
);
597 orig_offset
= key
.offset
- btrfs_file_extent_offset(leaf
, fi
);
598 memcpy(&new_key
, &key
, sizeof(new_key
));
600 if (start
== key
.offset
&& end
< extent_end
) {
603 if (extent_mergeable(leaf
, path
->slots
[0] - 1,
604 inode
->i_ino
, bytenr
, orig_offset
,
605 &other_start
, &other_end
)) {
606 new_key
.offset
= end
;
607 btrfs_set_item_key_safe(trans
, root
, path
, &new_key
);
608 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
609 struct btrfs_file_extent_item
);
610 btrfs_set_file_extent_num_bytes(leaf
, fi
,
612 btrfs_set_file_extent_offset(leaf
, fi
,
614 fi
= btrfs_item_ptr(leaf
, path
->slots
[0] - 1,
615 struct btrfs_file_extent_item
);
616 btrfs_set_file_extent_num_bytes(leaf
, fi
,
618 btrfs_mark_buffer_dirty(leaf
);
623 if (start
> key
.offset
&& end
== extent_end
) {
626 if (extent_mergeable(leaf
, path
->slots
[0] + 1,
627 inode
->i_ino
, bytenr
, orig_offset
,
628 &other_start
, &other_end
)) {
629 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
630 struct btrfs_file_extent_item
);
631 btrfs_set_file_extent_num_bytes(leaf
, fi
,
634 new_key
.offset
= start
;
635 btrfs_set_item_key_safe(trans
, root
, path
, &new_key
);
637 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
638 struct btrfs_file_extent_item
);
639 btrfs_set_file_extent_num_bytes(leaf
, fi
,
641 btrfs_set_file_extent_offset(leaf
, fi
,
642 start
- orig_offset
);
643 btrfs_mark_buffer_dirty(leaf
);
648 while (start
> key
.offset
|| end
< extent_end
) {
649 if (key
.offset
== start
)
652 new_key
.offset
= split
;
653 ret
= btrfs_duplicate_item(trans
, root
, path
, &new_key
);
654 if (ret
== -EAGAIN
) {
655 btrfs_release_path(root
, path
);
660 leaf
= path
->nodes
[0];
661 fi
= btrfs_item_ptr(leaf
, path
->slots
[0] - 1,
662 struct btrfs_file_extent_item
);
663 btrfs_set_file_extent_num_bytes(leaf
, fi
,
666 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
667 struct btrfs_file_extent_item
);
669 btrfs_set_file_extent_offset(leaf
, fi
, split
- orig_offset
);
670 btrfs_set_file_extent_num_bytes(leaf
, fi
,
672 btrfs_mark_buffer_dirty(leaf
);
674 ret
= btrfs_inc_extent_ref(trans
, root
, bytenr
, num_bytes
, 0,
675 root
->root_key
.objectid
,
676 inode
->i_ino
, orig_offset
);
679 if (split
== start
) {
682 BUG_ON(start
!= key
.offset
);
691 if (extent_mergeable(leaf
, path
->slots
[0] + 1,
692 inode
->i_ino
, bytenr
, orig_offset
,
693 &other_start
, &other_end
)) {
695 btrfs_release_path(root
, path
);
698 extent_end
= other_end
;
699 del_slot
= path
->slots
[0] + 1;
701 ret
= btrfs_free_extent(trans
, root
, bytenr
, num_bytes
,
702 0, root
->root_key
.objectid
,
703 inode
->i_ino
, orig_offset
);
708 if (extent_mergeable(leaf
, path
->slots
[0] - 1,
709 inode
->i_ino
, bytenr
, orig_offset
,
710 &other_start
, &other_end
)) {
712 btrfs_release_path(root
, path
);
715 key
.offset
= other_start
;
716 del_slot
= path
->slots
[0];
718 ret
= btrfs_free_extent(trans
, root
, bytenr
, num_bytes
,
719 0, root
->root_key
.objectid
,
720 inode
->i_ino
, orig_offset
);
723 fi
= btrfs_item_ptr(leaf
, path
->slots
[0],
724 struct btrfs_file_extent_item
);
726 btrfs_set_file_extent_type(leaf
, fi
,
727 BTRFS_FILE_EXTENT_REG
);
728 btrfs_mark_buffer_dirty(leaf
);
730 btrfs_set_file_extent_type(leaf
, fi
,
731 BTRFS_FILE_EXTENT_REG
);
732 btrfs_set_file_extent_num_bytes(leaf
, fi
,
733 extent_end
- key
.offset
);
734 btrfs_mark_buffer_dirty(leaf
);
736 ret
= btrfs_del_items(trans
, root
, path
, del_slot
, del_nr
);
740 btrfs_free_path(path
);
745 * this gets pages into the page cache and locks them down, it also properly
746 * waits for data=ordered extents to finish before allowing the pages to be
749 static noinline
int prepare_pages(struct btrfs_root
*root
, struct file
*file
,
750 struct page
**pages
, size_t num_pages
,
751 loff_t pos
, unsigned long first_index
,
752 unsigned long last_index
, size_t write_bytes
)
755 unsigned long index
= pos
>> PAGE_CACHE_SHIFT
;
756 struct inode
*inode
= fdentry(file
)->d_inode
;
761 start_pos
= pos
& ~((u64
)root
->sectorsize
- 1);
762 last_pos
= ((u64
)index
+ num_pages
) << PAGE_CACHE_SHIFT
;
764 if (start_pos
> inode
->i_size
) {
765 err
= btrfs_cont_expand(inode
, start_pos
);
770 memset(pages
, 0, num_pages
* sizeof(struct page
*));
772 for (i
= 0; i
< num_pages
; i
++) {
773 pages
[i
] = grab_cache_page(inode
->i_mapping
, index
+ i
);
778 wait_on_page_writeback(pages
[i
]);
780 if (start_pos
< inode
->i_size
) {
781 struct btrfs_ordered_extent
*ordered
;
782 lock_extent(&BTRFS_I(inode
)->io_tree
,
783 start_pos
, last_pos
- 1, GFP_NOFS
);
784 ordered
= btrfs_lookup_first_ordered_extent(inode
,
787 ordered
->file_offset
+ ordered
->len
> start_pos
&&
788 ordered
->file_offset
< last_pos
) {
789 btrfs_put_ordered_extent(ordered
);
790 unlock_extent(&BTRFS_I(inode
)->io_tree
,
791 start_pos
, last_pos
- 1, GFP_NOFS
);
792 for (i
= 0; i
< num_pages
; i
++) {
793 unlock_page(pages
[i
]);
794 page_cache_release(pages
[i
]);
796 btrfs_wait_ordered_range(inode
, start_pos
,
797 last_pos
- start_pos
);
801 btrfs_put_ordered_extent(ordered
);
803 clear_extent_bits(&BTRFS_I(inode
)->io_tree
, start_pos
,
804 last_pos
- 1, EXTENT_DIRTY
| EXTENT_DELALLOC
|
805 EXTENT_DO_ACCOUNTING
,
807 unlock_extent(&BTRFS_I(inode
)->io_tree
,
808 start_pos
, last_pos
- 1, GFP_NOFS
);
810 for (i
= 0; i
< num_pages
; i
++) {
811 clear_page_dirty_for_io(pages
[i
]);
812 set_page_extent_mapped(pages
[i
]);
813 WARN_ON(!PageLocked(pages
[i
]));
818 static ssize_t
btrfs_file_write(struct file
*file
, const char __user
*buf
,
819 size_t count
, loff_t
*ppos
)
823 ssize_t num_written
= 0;
826 struct inode
*inode
= fdentry(file
)->d_inode
;
827 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
828 struct page
**pages
= NULL
;
830 struct page
*pinned
[2];
831 unsigned long first_index
;
832 unsigned long last_index
;
835 will_write
= ((file
->f_flags
& O_DSYNC
) || IS_SYNC(inode
) ||
836 (file
->f_flags
& O_DIRECT
));
838 nrptrs
= min((count
+ PAGE_CACHE_SIZE
- 1) / PAGE_CACHE_SIZE
,
839 PAGE_CACHE_SIZE
/ (sizeof(struct page
*)));
846 vfs_check_frozen(inode
->i_sb
, SB_FREEZE_WRITE
);
848 /* do the reserve before the mutex lock in case we have to do some
849 * flushing. We wouldn't deadlock, but this is more polite.
851 err
= btrfs_reserve_metadata_for_delalloc(root
, inode
, 1);
855 mutex_lock(&inode
->i_mutex
);
857 current
->backing_dev_info
= inode
->i_mapping
->backing_dev_info
;
858 err
= generic_write_checks(file
, &pos
, &count
, S_ISBLK(inode
->i_mode
));
865 err
= file_remove_suid(file
);
869 file_update_time(file
);
871 pages
= kmalloc(nrptrs
* sizeof(struct page
*), GFP_KERNEL
);
873 /* generic_write_checks can change our pos */
876 BTRFS_I(inode
)->sequence
++;
877 first_index
= pos
>> PAGE_CACHE_SHIFT
;
878 last_index
= (pos
+ count
) >> PAGE_CACHE_SHIFT
;
881 * there are lots of better ways to do this, but this code
882 * makes sure the first and last page in the file range are
883 * up to date and ready for cow
885 if ((pos
& (PAGE_CACHE_SIZE
- 1))) {
886 pinned
[0] = grab_cache_page(inode
->i_mapping
, first_index
);
887 if (!PageUptodate(pinned
[0])) {
888 ret
= btrfs_readpage(NULL
, pinned
[0]);
890 wait_on_page_locked(pinned
[0]);
892 unlock_page(pinned
[0]);
895 if ((pos
+ count
) & (PAGE_CACHE_SIZE
- 1)) {
896 pinned
[1] = grab_cache_page(inode
->i_mapping
, last_index
);
897 if (!PageUptodate(pinned
[1])) {
898 ret
= btrfs_readpage(NULL
, pinned
[1]);
900 wait_on_page_locked(pinned
[1]);
902 unlock_page(pinned
[1]);
907 size_t offset
= pos
& (PAGE_CACHE_SIZE
- 1);
908 size_t write_bytes
= min(count
, nrptrs
*
909 (size_t)PAGE_CACHE_SIZE
-
911 size_t num_pages
= (write_bytes
+ PAGE_CACHE_SIZE
- 1) >>
914 WARN_ON(num_pages
> nrptrs
);
915 memset(pages
, 0, sizeof(struct page
*) * nrptrs
);
917 ret
= btrfs_check_data_free_space(root
, inode
, write_bytes
);
921 ret
= prepare_pages(root
, file
, pages
, num_pages
,
922 pos
, first_index
, last_index
,
925 btrfs_free_reserved_data_space(root
, inode
,
930 ret
= btrfs_copy_from_user(pos
, num_pages
,
931 write_bytes
, pages
, buf
);
933 btrfs_free_reserved_data_space(root
, inode
,
935 btrfs_drop_pages(pages
, num_pages
);
939 ret
= dirty_and_release_pages(NULL
, root
, file
, pages
,
940 num_pages
, pos
, write_bytes
);
941 btrfs_drop_pages(pages
, num_pages
);
943 btrfs_free_reserved_data_space(root
, inode
,
949 filemap_fdatawrite_range(inode
->i_mapping
, pos
,
950 pos
+ write_bytes
- 1);
952 balance_dirty_pages_ratelimited_nr(inode
->i_mapping
,
955 (root
->leafsize
>> PAGE_CACHE_SHIFT
) + 1)
956 btrfs_btree_balance_dirty(root
, 1);
957 btrfs_throttle(root
);
961 count
-= write_bytes
;
963 num_written
+= write_bytes
;
968 mutex_unlock(&inode
->i_mutex
);
971 btrfs_unreserve_metadata_for_delalloc(root
, inode
, 1);
976 page_cache_release(pinned
[0]);
978 page_cache_release(pinned
[1]);
982 * we want to make sure fsync finds this change
983 * but we haven't joined a transaction running right now.
985 * Later on, someone is sure to update the inode and get the
986 * real transid recorded.
988 * We set last_trans now to the fs_info generation + 1,
989 * this will either be one more than the running transaction
990 * or the generation used for the next transaction if there isn't
991 * one running right now.
993 BTRFS_I(inode
)->last_trans
= root
->fs_info
->generation
+ 1;
995 if (num_written
> 0 && will_write
) {
996 struct btrfs_trans_handle
*trans
;
998 err
= btrfs_wait_ordered_range(inode
, start_pos
, num_written
);
1002 if ((file
->f_flags
& O_DSYNC
) || IS_SYNC(inode
)) {
1003 trans
= btrfs_start_transaction(root
, 1);
1004 ret
= btrfs_log_dentry_safe(trans
, root
,
1007 ret
= btrfs_sync_log(trans
, root
);
1009 btrfs_end_transaction(trans
, root
);
1011 btrfs_commit_transaction(trans
, root
);
1012 } else if (ret
!= BTRFS_NO_LOG_SYNC
) {
1013 btrfs_commit_transaction(trans
, root
);
1015 btrfs_end_transaction(trans
, root
);
1018 if (file
->f_flags
& O_DIRECT
) {
1019 invalidate_mapping_pages(inode
->i_mapping
,
1020 start_pos
>> PAGE_CACHE_SHIFT
,
1021 (start_pos
+ num_written
- 1) >> PAGE_CACHE_SHIFT
);
1024 current
->backing_dev_info
= NULL
;
1025 return num_written
? num_written
: err
;
1028 int btrfs_release_file(struct inode
*inode
, struct file
*filp
)
1031 * ordered_data_close is set by settattr when we are about to truncate
1032 * a file from a non-zero size to a zero size. This tries to
1033 * flush down new bytes that may have been written if the
1034 * application were using truncate to replace a file in place.
1036 if (BTRFS_I(inode
)->ordered_data_close
) {
1037 BTRFS_I(inode
)->ordered_data_close
= 0;
1038 btrfs_add_ordered_operation(NULL
, BTRFS_I(inode
)->root
, inode
);
1039 if (inode
->i_size
> BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT
)
1040 filemap_flush(inode
->i_mapping
);
1042 if (filp
->private_data
)
1043 btrfs_ioctl_trans_end(filp
);
1048 * fsync call for both files and directories. This logs the inode into
1049 * the tree log instead of forcing full commits whenever possible.
1051 * It needs to call filemap_fdatawait so that all ordered extent updates are
1052 * in the metadata btree are up to date for copying to the log.
1054 * It drops the inode mutex before doing the tree log commit. This is an
1055 * important optimization for directories because holding the mutex prevents
1056 * new operations on the dir while we write to disk.
1058 int btrfs_sync_file(struct file
*file
, struct dentry
*dentry
, int datasync
)
1060 struct inode
*inode
= dentry
->d_inode
;
1061 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
1063 struct btrfs_trans_handle
*trans
;
1066 /* we wait first, since the writeback may change the inode */
1068 /* the VFS called filemap_fdatawrite for us */
1069 btrfs_wait_ordered_range(inode
, 0, (u64
)-1);
1073 * check the transaction that last modified this inode
1074 * and see if its already been committed
1076 if (!BTRFS_I(inode
)->last_trans
)
1080 * if the last transaction that changed this file was before
1081 * the current transaction, we can bail out now without any
1084 mutex_lock(&root
->fs_info
->trans_mutex
);
1085 if (BTRFS_I(inode
)->last_trans
<=
1086 root
->fs_info
->last_trans_committed
) {
1087 BTRFS_I(inode
)->last_trans
= 0;
1088 mutex_unlock(&root
->fs_info
->trans_mutex
);
1091 mutex_unlock(&root
->fs_info
->trans_mutex
);
1094 * ok we haven't committed the transaction yet, lets do a commit
1096 if (file
&& file
->private_data
)
1097 btrfs_ioctl_trans_end(file
);
1099 trans
= btrfs_start_transaction(root
, 1);
1105 ret
= btrfs_log_dentry_safe(trans
, root
, dentry
);
1109 /* we've logged all the items and now have a consistent
1110 * version of the file in the log. It is possible that
1111 * someone will come in and modify the file, but that's
1112 * fine because the log is consistent on disk, and we
1113 * have references to all of the file's extents
1115 * It is possible that someone will come in and log the
1116 * file again, but that will end up using the synchronization
1117 * inside btrfs_sync_log to keep things safe.
1119 mutex_unlock(&dentry
->d_inode
->i_mutex
);
1121 if (ret
!= BTRFS_NO_LOG_SYNC
) {
1123 ret
= btrfs_commit_transaction(trans
, root
);
1125 ret
= btrfs_sync_log(trans
, root
);
1127 ret
= btrfs_end_transaction(trans
, root
);
1129 ret
= btrfs_commit_transaction(trans
, root
);
1132 ret
= btrfs_end_transaction(trans
, root
);
1134 mutex_lock(&dentry
->d_inode
->i_mutex
);
1136 return ret
> 0 ? -EIO
: ret
;
1139 static const struct vm_operations_struct btrfs_file_vm_ops
= {
1140 .fault
= filemap_fault
,
1141 .page_mkwrite
= btrfs_page_mkwrite
,
1144 static int btrfs_file_mmap(struct file
*filp
, struct vm_area_struct
*vma
)
1146 vma
->vm_ops
= &btrfs_file_vm_ops
;
1147 file_accessed(filp
);
1151 const struct file_operations btrfs_file_operations
= {
1152 .llseek
= generic_file_llseek
,
1153 .read
= do_sync_read
,
1154 .aio_read
= generic_file_aio_read
,
1155 .splice_read
= generic_file_splice_read
,
1156 .write
= btrfs_file_write
,
1157 .mmap
= btrfs_file_mmap
,
1158 .open
= generic_file_open
,
1159 .release
= btrfs_release_file
,
1160 .fsync
= btrfs_sync_file
,
1161 .unlocked_ioctl
= btrfs_ioctl
,
1162 #ifdef CONFIG_COMPAT
1163 .compat_ioctl
= btrfs_ioctl
,