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/smp_lock.h>
26 #include <linux/backing-dev.h>
27 #include <linux/mpage.h>
28 #include <linux/swap.h>
29 #include <linux/writeback.h>
30 #include <linux/statfs.h>
31 #include <linux/compat.h>
34 #include "transaction.h"
35 #include "btrfs_inode.h"
37 #include "print-tree.h"
43 /* simple helper to fault in pages and copy. This should go away
44 * and be replaced with calls into generic code.
46 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
48 struct page **prepared_pages,
49 const char __user *buf)
53 int offset = pos & (PAGE_CACHE_SIZE - 1);
55 for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
56 size_t count = min_t(size_t,
57 PAGE_CACHE_SIZE - offset, write_bytes);
58 struct page *page = prepared_pages[i];
59 fault_in_pages_readable(buf, count);
61 /* Copy data from userspace to the current page */
63 page_fault = __copy_from_user(page_address(page) + offset,
65 /* Flush processor's dcache for this page */
66 flush_dcache_page(page);
74 return page_fault ? -EFAULT : 0;
78 * unlocks pages after btrfs_file_write is done with them
80 static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages)
83 for (i = 0; i < num_pages; i++) {
86 /* page checked is some magic around finding pages that
87 * have been modified without going through btrfs_set_page_dirty
90 ClearPageChecked(pages[i]);
91 unlock_page(pages[i]);
92 mark_page_accessed(pages[i]);
93 page_cache_release(pages[i]);
98 * after copy_from_user, pages need to be dirtied and we need to make
99 * sure holes are created between the current EOF and the start of
100 * any next extents (if required).
102 * this also makes the decision about creating an inline extent vs
103 * doing real data extents, marking pages dirty and delalloc as required.
105 static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
106 struct btrfs_root *root,
115 struct inode *inode = fdentry(file)->d_inode;
116 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
120 u64 end_of_last_block;
121 u64 end_pos = pos + write_bytes;
122 loff_t isize = i_size_read(inode);
124 start_pos = pos & ~((u64)root->sectorsize - 1);
125 num_bytes = (write_bytes + pos - start_pos +
126 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
128 end_of_last_block = start_pos + num_bytes - 1;
130 lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
131 trans = btrfs_join_transaction(root, 1);
136 btrfs_set_trans_block_group(trans, inode);
139 set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
141 /* check for reserved extents on each page, we don't want
142 * to reset the delalloc bit on things that already have
145 btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
146 for (i = 0; i < num_pages; i++) {
147 struct page *p = pages[i];
152 if (end_pos > isize) {
153 i_size_write(inode, end_pos);
154 btrfs_update_inode(trans, root, inode);
156 err = btrfs_end_transaction(trans, root);
158 unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
163 * this drops all the extents in the cache that intersect the range
164 * [start, end]. Existing extents are split as required.
166 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
169 struct extent_map *em;
170 struct extent_map *split = NULL;
171 struct extent_map *split2 = NULL;
172 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
173 u64 len = end - start + 1;
179 WARN_ON(end < start);
180 if (end == (u64)-1) {
186 split = alloc_extent_map(GFP_NOFS);
188 split2 = alloc_extent_map(GFP_NOFS);
190 spin_lock(&em_tree->lock);
191 em = lookup_extent_mapping(em_tree, start, len);
193 spin_unlock(&em_tree->lock);
197 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
198 spin_unlock(&em_tree->lock);
199 if (em->start <= start &&
200 (!testend || em->start + em->len >= start + len)) {
204 if (start < em->start) {
205 len = em->start - start;
207 len = start + len - (em->start + em->len);
208 start = em->start + em->len;
213 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
214 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
215 remove_extent_mapping(em_tree, em);
217 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
219 split->start = em->start;
220 split->len = start - em->start;
221 split->orig_start = em->orig_start;
222 split->block_start = em->block_start;
225 split->block_len = em->block_len;
227 split->block_len = split->len;
229 split->bdev = em->bdev;
230 split->flags = flags;
231 ret = add_extent_mapping(em_tree, split);
233 free_extent_map(split);
237 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
238 testend && em->start + em->len > start + len) {
239 u64 diff = start + len - em->start;
241 split->start = start + len;
242 split->len = em->start + em->len - (start + len);
243 split->bdev = em->bdev;
244 split->flags = flags;
247 split->block_len = em->block_len;
248 split->block_start = em->block_start;
249 split->orig_start = em->orig_start;
251 split->block_len = split->len;
252 split->block_start = em->block_start + diff;
253 split->orig_start = split->start;
256 ret = add_extent_mapping(em_tree, split);
258 free_extent_map(split);
261 spin_unlock(&em_tree->lock);
265 /* once for the tree*/
269 free_extent_map(split);
271 free_extent_map(split2);
276 * this is very complex, but the basic idea is to drop all extents
277 * in the range start - end. hint_block is filled in with a block number
278 * that would be a good hint to the block allocator for this file.
280 * If an extent intersects the range but is not entirely inside the range
281 * it is either truncated or split. Anything entirely inside the range
282 * is deleted from the tree.
284 * inline_limit is used to tell this code which offsets in the file to keep
285 * if they contain inline extents.
287 noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
288 struct btrfs_root *root, struct inode *inode,
289 u64 start, u64 end, u64 locked_end,
290 u64 inline_limit, u64 *hint_byte)
293 u64 search_start = start;
296 u64 orig_locked_end = locked_end;
299 u16 other_encoding = 0;
300 struct extent_buffer *leaf;
301 struct btrfs_file_extent_item *extent;
302 struct btrfs_path *path;
303 struct btrfs_key key;
304 struct btrfs_file_extent_item old;
315 btrfs_drop_extent_cache(inode, start, end - 1, 0);
317 path = btrfs_alloc_path();
322 btrfs_release_path(root, path);
323 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
328 if (path->slots[0] == 0) {
342 leaf = path->nodes[0];
343 slot = path->slots[0];
345 btrfs_item_key_to_cpu(leaf, &key, slot);
346 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
350 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
351 key.objectid != inode->i_ino) {
355 search_start = max(key.offset, start);
358 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
359 extent = btrfs_item_ptr(leaf, slot,
360 struct btrfs_file_extent_item);
361 found_type = btrfs_file_extent_type(leaf, extent);
362 compression = btrfs_file_extent_compression(leaf,
364 encryption = btrfs_file_extent_encryption(leaf,
366 other_encoding = btrfs_file_extent_other_encoding(leaf,
368 if (found_type == BTRFS_FILE_EXTENT_REG ||
369 found_type == BTRFS_FILE_EXTENT_PREALLOC) {
371 btrfs_file_extent_disk_bytenr(leaf,
374 *hint_byte = extent_end;
376 extent_end = key.offset +
377 btrfs_file_extent_num_bytes(leaf, extent);
378 ram_bytes = btrfs_file_extent_ram_bytes(leaf,
381 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
383 extent_end = key.offset +
384 btrfs_file_extent_inline_len(leaf, extent);
387 extent_end = search_start;
390 /* we found nothing we can drop */
391 if ((!found_extent && !found_inline) ||
392 search_start >= extent_end) {
395 nritems = btrfs_header_nritems(leaf);
396 if (slot >= nritems - 1) {
397 nextret = btrfs_next_leaf(root, path);
407 if (end <= extent_end && start >= key.offset && found_inline)
408 *hint_byte = EXTENT_MAP_INLINE;
411 read_extent_buffer(leaf, &old, (unsigned long)extent,
415 if (end < extent_end && end >= key.offset) {
417 if (found_inline && start <= key.offset)
421 if (bookend && found_extent) {
422 if (locked_end < extent_end) {
423 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
424 locked_end, extent_end - 1,
427 btrfs_release_path(root, path);
428 lock_extent(&BTRFS_I(inode)->io_tree,
429 locked_end, extent_end - 1,
431 locked_end = extent_end;
434 locked_end = extent_end;
436 disk_bytenr = le64_to_cpu(old.disk_bytenr);
437 if (disk_bytenr != 0) {
438 ret = btrfs_inc_extent_ref(trans, root,
440 le64_to_cpu(old.disk_num_bytes), 0,
441 root->root_key.objectid,
442 key.objectid, key.offset -
443 le64_to_cpu(old.offset));
449 u64 mask = root->sectorsize - 1;
450 search_start = (extent_end + mask) & ~mask;
452 search_start = extent_end;
454 /* truncate existing extent */
455 if (start > key.offset) {
459 WARN_ON(start & (root->sectorsize - 1));
461 new_num = start - key.offset;
462 old_num = btrfs_file_extent_num_bytes(leaf,
465 btrfs_file_extent_disk_bytenr(leaf,
467 if (btrfs_file_extent_disk_bytenr(leaf,
469 inode_sub_bytes(inode, old_num -
472 btrfs_set_file_extent_num_bytes(leaf,
474 btrfs_mark_buffer_dirty(leaf);
475 } else if (key.offset < inline_limit &&
476 (end > extent_end) &&
477 (inline_limit < extent_end)) {
479 new_size = btrfs_file_extent_calc_inline_size(
480 inline_limit - key.offset);
481 inode_sub_bytes(inode, extent_end -
483 btrfs_set_file_extent_ram_bytes(leaf, extent,
485 if (!compression && !encryption) {
486 btrfs_truncate_item(trans, root, path,
491 /* delete the entire extent */
494 inode_sub_bytes(inode, extent_end -
496 ret = btrfs_del_item(trans, root, path);
497 /* TODO update progress marker and return */
500 btrfs_release_path(root, path);
501 /* the extent will be freed later */
503 if (bookend && found_inline && start <= key.offset) {
505 new_size = btrfs_file_extent_calc_inline_size(
507 inode_sub_bytes(inode, end - key.offset);
508 btrfs_set_file_extent_ram_bytes(leaf, extent,
510 if (!compression && !encryption)
511 ret = btrfs_truncate_item(trans, root, path,
515 /* create bookend, splitting the extent in two */
516 if (bookend && found_extent) {
517 struct btrfs_key ins;
518 ins.objectid = inode->i_ino;
520 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
522 btrfs_release_path(root, path);
523 path->leave_spinning = 1;
524 ret = btrfs_insert_empty_item(trans, root, path, &ins,
528 leaf = path->nodes[0];
529 extent = btrfs_item_ptr(leaf, path->slots[0],
530 struct btrfs_file_extent_item);
531 write_extent_buffer(leaf, &old,
532 (unsigned long)extent, sizeof(old));
534 btrfs_set_file_extent_compression(leaf, extent,
536 btrfs_set_file_extent_encryption(leaf, extent,
538 btrfs_set_file_extent_other_encoding(leaf, extent,
540 btrfs_set_file_extent_offset(leaf, extent,
541 le64_to_cpu(old.offset) + end - key.offset);
542 WARN_ON(le64_to_cpu(old.num_bytes) <
544 btrfs_set_file_extent_num_bytes(leaf, extent,
548 * set the ram bytes to the size of the full extent
549 * before splitting. This is a worst case flag,
550 * but its the best we can do because we don't know
551 * how splitting affects compression
553 btrfs_set_file_extent_ram_bytes(leaf, extent,
555 btrfs_set_file_extent_type(leaf, extent, found_type);
557 btrfs_unlock_up_safe(path, 1);
558 btrfs_mark_buffer_dirty(path->nodes[0]);
559 btrfs_set_lock_blocking(path->nodes[0]);
561 path->leave_spinning = 0;
562 btrfs_release_path(root, path);
563 if (disk_bytenr != 0)
564 inode_add_bytes(inode, extent_end - end);
567 if (found_extent && !keep) {
568 u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr);
570 if (old_disk_bytenr != 0) {
571 inode_sub_bytes(inode,
572 le64_to_cpu(old.num_bytes));
573 ret = btrfs_free_extent(trans, root,
575 le64_to_cpu(old.disk_num_bytes),
576 0, root->root_key.objectid,
577 key.objectid, key.offset -
578 le64_to_cpu(old.offset));
580 *hint_byte = old_disk_bytenr;
584 if (search_start >= end) {
590 btrfs_free_path(path);
591 if (locked_end > orig_locked_end) {
592 unlock_extent(&BTRFS_I(inode)->io_tree, orig_locked_end,
593 locked_end - 1, GFP_NOFS);
598 static int extent_mergeable(struct extent_buffer *leaf, int slot,
599 u64 objectid, u64 bytenr, u64 *start, u64 *end)
601 struct btrfs_file_extent_item *fi;
602 struct btrfs_key key;
605 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
608 btrfs_item_key_to_cpu(leaf, &key, slot);
609 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
612 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
613 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
614 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
615 btrfs_file_extent_compression(leaf, fi) ||
616 btrfs_file_extent_encryption(leaf, fi) ||
617 btrfs_file_extent_other_encoding(leaf, fi))
620 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
621 if ((*start && *start != key.offset) || (*end && *end != extent_end))
630 * Mark extent in the range start - end as written.
632 * This changes extent type from 'pre-allocated' to 'regular'. If only
633 * part of extent is marked as written, the extent will be split into
636 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
637 struct btrfs_root *root,
638 struct inode *inode, u64 start, u64 end)
640 struct extent_buffer *leaf;
641 struct btrfs_path *path;
642 struct btrfs_file_extent_item *fi;
643 struct btrfs_key key;
651 u64 locked_end = end;
656 btrfs_drop_extent_cache(inode, start, end - 1, 0);
658 path = btrfs_alloc_path();
661 key.objectid = inode->i_ino;
662 key.type = BTRFS_EXTENT_DATA_KEY;
666 key.offset = split - 1;
668 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
669 if (ret > 0 && path->slots[0] > 0)
672 leaf = path->nodes[0];
673 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
674 BUG_ON(key.objectid != inode->i_ino ||
675 key.type != BTRFS_EXTENT_DATA_KEY);
676 fi = btrfs_item_ptr(leaf, path->slots[0],
677 struct btrfs_file_extent_item);
678 extent_type = btrfs_file_extent_type(leaf, fi);
679 BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC);
680 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
681 BUG_ON(key.offset > start || extent_end < end);
683 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
684 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
685 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
687 if (key.offset == start)
690 if (key.offset == start && extent_end == end) {
695 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
696 bytenr, &other_start, &other_end)) {
697 extent_end = other_end;
698 del_slot = path->slots[0] + 1;
700 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
701 0, root->root_key.objectid,
702 inode->i_ino, orig_offset);
707 if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino,
708 bytenr, &other_start, &other_end)) {
709 key.offset = other_start;
710 del_slot = path->slots[0];
712 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
713 0, root->root_key.objectid,
714 inode->i_ino, orig_offset);
719 btrfs_set_file_extent_type(leaf, fi,
720 BTRFS_FILE_EXTENT_REG);
724 fi = btrfs_item_ptr(leaf, del_slot - 1,
725 struct btrfs_file_extent_item);
726 btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
727 btrfs_set_file_extent_num_bytes(leaf, fi,
728 extent_end - key.offset);
729 btrfs_mark_buffer_dirty(leaf);
731 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
734 } else if (split == start) {
735 if (locked_end < extent_end) {
736 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
737 locked_end, extent_end - 1, GFP_NOFS);
739 btrfs_release_path(root, path);
740 lock_extent(&BTRFS_I(inode)->io_tree,
741 locked_end, extent_end - 1, GFP_NOFS);
742 locked_end = extent_end;
745 locked_end = extent_end;
747 btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
749 BUG_ON(key.offset != start);
751 btrfs_set_file_extent_offset(leaf, fi, key.offset -
753 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
754 btrfs_set_item_key_safe(trans, root, path, &key);
758 if (extent_end == end) {
760 extent_type = BTRFS_FILE_EXTENT_REG;
762 if (extent_end == end && split == start) {
765 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
766 bytenr, &other_start, &other_end)) {
768 fi = btrfs_item_ptr(leaf, path->slots[0],
769 struct btrfs_file_extent_item);
771 btrfs_set_item_key_safe(trans, root, path, &key);
772 btrfs_set_file_extent_offset(leaf, fi, key.offset -
774 btrfs_set_file_extent_num_bytes(leaf, fi,
779 if (extent_end == end && split == end) {
782 if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino,
783 bytenr, &other_start, &other_end)) {
785 fi = btrfs_item_ptr(leaf, path->slots[0],
786 struct btrfs_file_extent_item);
787 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end -
793 btrfs_mark_buffer_dirty(leaf);
795 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
796 root->root_key.objectid,
797 inode->i_ino, orig_offset);
799 btrfs_release_path(root, path);
802 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi));
805 leaf = path->nodes[0];
806 fi = btrfs_item_ptr(leaf, path->slots[0],
807 struct btrfs_file_extent_item);
808 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
809 btrfs_set_file_extent_type(leaf, fi, extent_type);
810 btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr);
811 btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
812 btrfs_set_file_extent_offset(leaf, fi, key.offset - orig_offset);
813 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset);
814 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
815 btrfs_set_file_extent_compression(leaf, fi, 0);
816 btrfs_set_file_extent_encryption(leaf, fi, 0);
817 btrfs_set_file_extent_other_encoding(leaf, fi, 0);
819 btrfs_mark_buffer_dirty(leaf);
822 btrfs_release_path(root, path);
823 if (split_end && split == start) {
827 if (locked_end > end) {
828 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
831 btrfs_free_path(path);
836 * this gets pages into the page cache and locks them down, it also properly
837 * waits for data=ordered extents to finish before allowing the pages to be
840 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
841 struct page **pages, size_t num_pages,
842 loff_t pos, unsigned long first_index,
843 unsigned long last_index, size_t write_bytes)
846 unsigned long index = pos >> PAGE_CACHE_SHIFT;
847 struct inode *inode = fdentry(file)->d_inode;
852 start_pos = pos & ~((u64)root->sectorsize - 1);
853 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
855 if (start_pos > inode->i_size) {
856 err = btrfs_cont_expand(inode, start_pos);
861 memset(pages, 0, num_pages * sizeof(struct page *));
863 for (i = 0; i < num_pages; i++) {
864 pages[i] = grab_cache_page(inode->i_mapping, index + i);
869 wait_on_page_writeback(pages[i]);
871 if (start_pos < inode->i_size) {
872 struct btrfs_ordered_extent *ordered;
873 lock_extent(&BTRFS_I(inode)->io_tree,
874 start_pos, last_pos - 1, GFP_NOFS);
875 ordered = btrfs_lookup_first_ordered_extent(inode,
878 ordered->file_offset + ordered->len > start_pos &&
879 ordered->file_offset < last_pos) {
880 btrfs_put_ordered_extent(ordered);
881 unlock_extent(&BTRFS_I(inode)->io_tree,
882 start_pos, last_pos - 1, GFP_NOFS);
883 for (i = 0; i < num_pages; i++) {
884 unlock_page(pages[i]);
885 page_cache_release(pages[i]);
887 btrfs_wait_ordered_range(inode, start_pos,
888 last_pos - start_pos);
892 btrfs_put_ordered_extent(ordered);
894 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
895 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
897 unlock_extent(&BTRFS_I(inode)->io_tree,
898 start_pos, last_pos - 1, GFP_NOFS);
900 for (i = 0; i < num_pages; i++) {
901 clear_page_dirty_for_io(pages[i]);
902 set_page_extent_mapped(pages[i]);
903 WARN_ON(!PageLocked(pages[i]));
908 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
909 size_t count, loff_t *ppos)
913 ssize_t num_written = 0;
916 struct inode *inode = fdentry(file)->d_inode;
917 struct btrfs_root *root = BTRFS_I(inode)->root;
918 struct page **pages = NULL;
920 struct page *pinned[2];
921 unsigned long first_index;
922 unsigned long last_index;
925 will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) ||
926 (file->f_flags & O_DIRECT));
928 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
929 PAGE_CACHE_SIZE / (sizeof(struct page *)));
936 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
937 current->backing_dev_info = inode->i_mapping->backing_dev_info;
938 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
944 err = file_remove_suid(file);
947 file_update_time(file);
949 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
951 mutex_lock(&inode->i_mutex);
952 BTRFS_I(inode)->sequence++;
953 first_index = pos >> PAGE_CACHE_SHIFT;
954 last_index = (pos + count) >> PAGE_CACHE_SHIFT;
957 * there are lots of better ways to do this, but this code
958 * makes sure the first and last page in the file range are
959 * up to date and ready for cow
961 if ((pos & (PAGE_CACHE_SIZE - 1))) {
962 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
963 if (!PageUptodate(pinned[0])) {
964 ret = btrfs_readpage(NULL, pinned[0]);
966 wait_on_page_locked(pinned[0]);
968 unlock_page(pinned[0]);
971 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
972 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
973 if (!PageUptodate(pinned[1])) {
974 ret = btrfs_readpage(NULL, pinned[1]);
976 wait_on_page_locked(pinned[1]);
978 unlock_page(pinned[1]);
983 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
984 size_t write_bytes = min(count, nrptrs *
985 (size_t)PAGE_CACHE_SIZE -
987 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
990 WARN_ON(num_pages > nrptrs);
991 memset(pages, 0, sizeof(struct page *) * nrptrs);
993 ret = btrfs_check_data_free_space(root, inode, write_bytes);
997 ret = prepare_pages(root, file, pages, num_pages,
998 pos, first_index, last_index,
1001 btrfs_free_reserved_data_space(root, inode,
1006 ret = btrfs_copy_from_user(pos, num_pages,
1007 write_bytes, pages, buf);
1009 btrfs_free_reserved_data_space(root, inode,
1011 btrfs_drop_pages(pages, num_pages);
1015 ret = dirty_and_release_pages(NULL, root, file, pages,
1016 num_pages, pos, write_bytes);
1017 btrfs_drop_pages(pages, num_pages);
1019 btrfs_free_reserved_data_space(root, inode,
1025 btrfs_fdatawrite_range(inode->i_mapping, pos,
1026 pos + write_bytes - 1,
1029 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1032 (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1033 btrfs_btree_balance_dirty(root, 1);
1034 btrfs_throttle(root);
1038 count -= write_bytes;
1040 num_written += write_bytes;
1045 mutex_unlock(&inode->i_mutex);
1052 page_cache_release(pinned[0]);
1054 page_cache_release(pinned[1]);
1058 * we want to make sure fsync finds this change
1059 * but we haven't joined a transaction running right now.
1061 * Later on, someone is sure to update the inode and get the
1062 * real transid recorded.
1064 * We set last_trans now to the fs_info generation + 1,
1065 * this will either be one more than the running transaction
1066 * or the generation used for the next transaction if there isn't
1067 * one running right now.
1069 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1071 if (num_written > 0 && will_write) {
1072 struct btrfs_trans_handle *trans;
1074 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1078 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
1079 trans = btrfs_start_transaction(root, 1);
1080 ret = btrfs_log_dentry_safe(trans, root,
1083 ret = btrfs_sync_log(trans, root);
1085 btrfs_end_transaction(trans, root);
1087 btrfs_commit_transaction(trans, root);
1089 btrfs_commit_transaction(trans, root);
1092 if (file->f_flags & O_DIRECT) {
1093 invalidate_mapping_pages(inode->i_mapping,
1094 start_pos >> PAGE_CACHE_SHIFT,
1095 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1098 current->backing_dev_info = NULL;
1099 return num_written ? num_written : err;
1102 int btrfs_release_file(struct inode *inode, struct file *filp)
1105 * ordered_data_close is set by settattr when we are about to truncate
1106 * a file from a non-zero size to a zero size. This tries to
1107 * flush down new bytes that may have been written if the
1108 * application were using truncate to replace a file in place.
1110 if (BTRFS_I(inode)->ordered_data_close) {
1111 BTRFS_I(inode)->ordered_data_close = 0;
1112 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1113 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1114 filemap_flush(inode->i_mapping);
1116 if (filp->private_data)
1117 btrfs_ioctl_trans_end(filp);
1122 * fsync call for both files and directories. This logs the inode into
1123 * the tree log instead of forcing full commits whenever possible.
1125 * It needs to call filemap_fdatawait so that all ordered extent updates are
1126 * in the metadata btree are up to date for copying to the log.
1128 * It drops the inode mutex before doing the tree log commit. This is an
1129 * important optimization for directories because holding the mutex prevents
1130 * new operations on the dir while we write to disk.
1132 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
1134 struct inode *inode = dentry->d_inode;
1135 struct btrfs_root *root = BTRFS_I(inode)->root;
1137 struct btrfs_trans_handle *trans;
1140 * check the transaction that last modified this inode
1141 * and see if its already been committed
1143 if (!BTRFS_I(inode)->last_trans)
1146 mutex_lock(&root->fs_info->trans_mutex);
1147 if (BTRFS_I(inode)->last_trans <=
1148 root->fs_info->last_trans_committed) {
1149 BTRFS_I(inode)->last_trans = 0;
1150 mutex_unlock(&root->fs_info->trans_mutex);
1153 mutex_unlock(&root->fs_info->trans_mutex);
1156 filemap_fdatawrite(inode->i_mapping);
1157 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1160 if (datasync && !(inode->i_state & I_DIRTY_PAGES))
1163 * ok we haven't committed the transaction yet, lets do a commit
1165 if (file && file->private_data)
1166 btrfs_ioctl_trans_end(file);
1168 trans = btrfs_start_transaction(root, 1);
1174 ret = btrfs_log_dentry_safe(trans, root, dentry);
1178 /* we've logged all the items and now have a consistent
1179 * version of the file in the log. It is possible that
1180 * someone will come in and modify the file, but that's
1181 * fine because the log is consistent on disk, and we
1182 * have references to all of the file's extents
1184 * It is possible that someone will come in and log the
1185 * file again, but that will end up using the synchronization
1186 * inside btrfs_sync_log to keep things safe.
1188 mutex_unlock(&dentry->d_inode->i_mutex);
1191 ret = btrfs_commit_transaction(trans, root);
1193 ret = btrfs_sync_log(trans, root);
1195 ret = btrfs_end_transaction(trans, root);
1197 ret = btrfs_commit_transaction(trans, root);
1199 mutex_lock(&dentry->d_inode->i_mutex);
1201 return ret > 0 ? EIO : ret;
1204 static struct vm_operations_struct btrfs_file_vm_ops = {
1205 .fault = filemap_fault,
1206 .page_mkwrite = btrfs_page_mkwrite,
1209 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1211 vma->vm_ops = &btrfs_file_vm_ops;
1212 file_accessed(filp);
1216 struct file_operations btrfs_file_operations = {
1217 .llseek = generic_file_llseek,
1218 .read = do_sync_read,
1219 .aio_read = generic_file_aio_read,
1220 .splice_read = generic_file_splice_read,
1221 .write = btrfs_file_write,
1222 .mmap = btrfs_file_mmap,
1223 .open = generic_file_open,
1224 .release = btrfs_release_file,
1225 .fsync = btrfs_sync_file,
1226 .unlocked_ioctl = btrfs_ioctl,
1227 #ifdef CONFIG_COMPAT
1228 .compat_ioctl = btrfs_ioctl,