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 /* we've only changed i_size in ram, and we haven't updated
155 * the disk i_size. There is no need to log the inode
159 err = btrfs_end_transaction(trans, root);
161 unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
166 * this drops all the extents in the cache that intersect the range
167 * [start, end]. Existing extents are split as required.
169 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
172 struct extent_map *em;
173 struct extent_map *split = NULL;
174 struct extent_map *split2 = NULL;
175 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
176 u64 len = end - start + 1;
182 WARN_ON(end < start);
183 if (end == (u64)-1) {
189 split = alloc_extent_map(GFP_NOFS);
191 split2 = alloc_extent_map(GFP_NOFS);
193 spin_lock(&em_tree->lock);
194 em = lookup_extent_mapping(em_tree, start, len);
196 spin_unlock(&em_tree->lock);
200 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
201 spin_unlock(&em_tree->lock);
202 if (em->start <= start &&
203 (!testend || em->start + em->len >= start + len)) {
207 if (start < em->start) {
208 len = em->start - start;
210 len = start + len - (em->start + em->len);
211 start = em->start + em->len;
216 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
217 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
218 remove_extent_mapping(em_tree, em);
220 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
222 split->start = em->start;
223 split->len = start - em->start;
224 split->orig_start = em->orig_start;
225 split->block_start = em->block_start;
228 split->block_len = em->block_len;
230 split->block_len = split->len;
232 split->bdev = em->bdev;
233 split->flags = flags;
234 ret = add_extent_mapping(em_tree, split);
236 free_extent_map(split);
240 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
241 testend && em->start + em->len > start + len) {
242 u64 diff = start + len - em->start;
244 split->start = start + len;
245 split->len = em->start + em->len - (start + len);
246 split->bdev = em->bdev;
247 split->flags = flags;
250 split->block_len = em->block_len;
251 split->block_start = em->block_start;
252 split->orig_start = em->orig_start;
254 split->block_len = split->len;
255 split->block_start = em->block_start + diff;
256 split->orig_start = split->start;
259 ret = add_extent_mapping(em_tree, split);
261 free_extent_map(split);
264 spin_unlock(&em_tree->lock);
268 /* once for the tree*/
272 free_extent_map(split);
274 free_extent_map(split2);
279 * this is very complex, but the basic idea is to drop all extents
280 * in the range start - end. hint_block is filled in with a block number
281 * that would be a good hint to the block allocator for this file.
283 * If an extent intersects the range but is not entirely inside the range
284 * it is either truncated or split. Anything entirely inside the range
285 * is deleted from the tree.
287 * inline_limit is used to tell this code which offsets in the file to keep
288 * if they contain inline extents.
290 noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
291 struct btrfs_root *root, struct inode *inode,
292 u64 start, u64 end, u64 locked_end,
293 u64 inline_limit, u64 *hint_byte)
296 u64 search_start = start;
299 u64 orig_locked_end = locked_end;
302 u16 other_encoding = 0;
303 struct extent_buffer *leaf;
304 struct btrfs_file_extent_item *extent;
305 struct btrfs_path *path;
306 struct btrfs_key key;
307 struct btrfs_file_extent_item old;
318 btrfs_drop_extent_cache(inode, start, end - 1, 0);
320 path = btrfs_alloc_path();
325 btrfs_release_path(root, path);
326 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
331 if (path->slots[0] == 0) {
345 leaf = path->nodes[0];
346 slot = path->slots[0];
348 btrfs_item_key_to_cpu(leaf, &key, slot);
349 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
353 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
354 key.objectid != inode->i_ino) {
358 search_start = max(key.offset, start);
361 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
362 extent = btrfs_item_ptr(leaf, slot,
363 struct btrfs_file_extent_item);
364 found_type = btrfs_file_extent_type(leaf, extent);
365 compression = btrfs_file_extent_compression(leaf,
367 encryption = btrfs_file_extent_encryption(leaf,
369 other_encoding = btrfs_file_extent_other_encoding(leaf,
371 if (found_type == BTRFS_FILE_EXTENT_REG ||
372 found_type == BTRFS_FILE_EXTENT_PREALLOC) {
374 btrfs_file_extent_disk_bytenr(leaf,
377 *hint_byte = extent_end;
379 extent_end = key.offset +
380 btrfs_file_extent_num_bytes(leaf, extent);
381 ram_bytes = btrfs_file_extent_ram_bytes(leaf,
384 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
386 extent_end = key.offset +
387 btrfs_file_extent_inline_len(leaf, extent);
390 extent_end = search_start;
393 /* we found nothing we can drop */
394 if ((!found_extent && !found_inline) ||
395 search_start >= extent_end) {
398 nritems = btrfs_header_nritems(leaf);
399 if (slot >= nritems - 1) {
400 nextret = btrfs_next_leaf(root, path);
410 if (end <= extent_end && start >= key.offset && found_inline)
411 *hint_byte = EXTENT_MAP_INLINE;
414 read_extent_buffer(leaf, &old, (unsigned long)extent,
418 if (end < extent_end && end >= key.offset) {
420 if (found_inline && start <= key.offset)
424 if (bookend && found_extent) {
425 if (locked_end < extent_end) {
426 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
427 locked_end, extent_end - 1,
430 btrfs_release_path(root, path);
431 lock_extent(&BTRFS_I(inode)->io_tree,
432 locked_end, extent_end - 1,
434 locked_end = extent_end;
437 locked_end = extent_end;
439 disk_bytenr = le64_to_cpu(old.disk_bytenr);
440 if (disk_bytenr != 0) {
441 ret = btrfs_inc_extent_ref(trans, root,
443 le64_to_cpu(old.disk_num_bytes), 0,
444 root->root_key.objectid,
445 key.objectid, key.offset -
446 le64_to_cpu(old.offset));
452 u64 mask = root->sectorsize - 1;
453 search_start = (extent_end + mask) & ~mask;
455 search_start = extent_end;
457 /* truncate existing extent */
458 if (start > key.offset) {
462 WARN_ON(start & (root->sectorsize - 1));
464 new_num = start - key.offset;
465 old_num = btrfs_file_extent_num_bytes(leaf,
468 btrfs_file_extent_disk_bytenr(leaf,
470 if (btrfs_file_extent_disk_bytenr(leaf,
472 inode_sub_bytes(inode, old_num -
475 btrfs_set_file_extent_num_bytes(leaf,
477 btrfs_mark_buffer_dirty(leaf);
478 } else if (key.offset < inline_limit &&
479 (end > extent_end) &&
480 (inline_limit < extent_end)) {
482 new_size = btrfs_file_extent_calc_inline_size(
483 inline_limit - key.offset);
484 inode_sub_bytes(inode, extent_end -
486 btrfs_set_file_extent_ram_bytes(leaf, extent,
488 if (!compression && !encryption) {
489 btrfs_truncate_item(trans, root, path,
494 /* delete the entire extent */
497 inode_sub_bytes(inode, extent_end -
499 ret = btrfs_del_item(trans, root, path);
500 /* TODO update progress marker and return */
503 btrfs_release_path(root, path);
504 /* the extent will be freed later */
506 if (bookend && found_inline && start <= key.offset) {
508 new_size = btrfs_file_extent_calc_inline_size(
510 inode_sub_bytes(inode, end - key.offset);
511 btrfs_set_file_extent_ram_bytes(leaf, extent,
513 if (!compression && !encryption)
514 ret = btrfs_truncate_item(trans, root, path,
518 /* create bookend, splitting the extent in two */
519 if (bookend && found_extent) {
520 struct btrfs_key ins;
521 ins.objectid = inode->i_ino;
523 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
525 btrfs_release_path(root, path);
526 path->leave_spinning = 1;
527 ret = btrfs_insert_empty_item(trans, root, path, &ins,
531 leaf = path->nodes[0];
532 extent = btrfs_item_ptr(leaf, path->slots[0],
533 struct btrfs_file_extent_item);
534 write_extent_buffer(leaf, &old,
535 (unsigned long)extent, sizeof(old));
537 btrfs_set_file_extent_compression(leaf, extent,
539 btrfs_set_file_extent_encryption(leaf, extent,
541 btrfs_set_file_extent_other_encoding(leaf, extent,
543 btrfs_set_file_extent_offset(leaf, extent,
544 le64_to_cpu(old.offset) + end - key.offset);
545 WARN_ON(le64_to_cpu(old.num_bytes) <
547 btrfs_set_file_extent_num_bytes(leaf, extent,
551 * set the ram bytes to the size of the full extent
552 * before splitting. This is a worst case flag,
553 * but its the best we can do because we don't know
554 * how splitting affects compression
556 btrfs_set_file_extent_ram_bytes(leaf, extent,
558 btrfs_set_file_extent_type(leaf, extent, found_type);
560 btrfs_unlock_up_safe(path, 1);
561 btrfs_mark_buffer_dirty(path->nodes[0]);
562 btrfs_set_lock_blocking(path->nodes[0]);
564 path->leave_spinning = 0;
565 btrfs_release_path(root, path);
566 if (disk_bytenr != 0)
567 inode_add_bytes(inode, extent_end - end);
570 if (found_extent && !keep) {
571 u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr);
573 if (old_disk_bytenr != 0) {
574 inode_sub_bytes(inode,
575 le64_to_cpu(old.num_bytes));
576 ret = btrfs_free_extent(trans, root,
578 le64_to_cpu(old.disk_num_bytes),
579 0, root->root_key.objectid,
580 key.objectid, key.offset -
581 le64_to_cpu(old.offset));
583 *hint_byte = old_disk_bytenr;
587 if (search_start >= end) {
593 btrfs_free_path(path);
594 if (locked_end > orig_locked_end) {
595 unlock_extent(&BTRFS_I(inode)->io_tree, orig_locked_end,
596 locked_end - 1, GFP_NOFS);
601 static int extent_mergeable(struct extent_buffer *leaf, int slot,
602 u64 objectid, u64 bytenr, u64 *start, u64 *end)
604 struct btrfs_file_extent_item *fi;
605 struct btrfs_key key;
608 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
611 btrfs_item_key_to_cpu(leaf, &key, slot);
612 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
615 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
616 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
617 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
618 btrfs_file_extent_compression(leaf, fi) ||
619 btrfs_file_extent_encryption(leaf, fi) ||
620 btrfs_file_extent_other_encoding(leaf, fi))
623 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
624 if ((*start && *start != key.offset) || (*end && *end != extent_end))
633 * Mark extent in the range start - end as written.
635 * This changes extent type from 'pre-allocated' to 'regular'. If only
636 * part of extent is marked as written, the extent will be split into
639 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
640 struct btrfs_root *root,
641 struct inode *inode, u64 start, u64 end)
643 struct extent_buffer *leaf;
644 struct btrfs_path *path;
645 struct btrfs_file_extent_item *fi;
646 struct btrfs_key key;
654 u64 locked_end = end;
659 btrfs_drop_extent_cache(inode, start, end - 1, 0);
661 path = btrfs_alloc_path();
664 key.objectid = inode->i_ino;
665 key.type = BTRFS_EXTENT_DATA_KEY;
669 key.offset = split - 1;
671 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
672 if (ret > 0 && path->slots[0] > 0)
675 leaf = path->nodes[0];
676 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
677 BUG_ON(key.objectid != inode->i_ino ||
678 key.type != BTRFS_EXTENT_DATA_KEY);
679 fi = btrfs_item_ptr(leaf, path->slots[0],
680 struct btrfs_file_extent_item);
681 extent_type = btrfs_file_extent_type(leaf, fi);
682 BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC);
683 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
684 BUG_ON(key.offset > start || extent_end < end);
686 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
687 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
688 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
690 if (key.offset == start)
693 if (key.offset == start && extent_end == end) {
698 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
699 bytenr, &other_start, &other_end)) {
700 extent_end = other_end;
701 del_slot = path->slots[0] + 1;
703 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
704 0, root->root_key.objectid,
705 inode->i_ino, orig_offset);
710 if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino,
711 bytenr, &other_start, &other_end)) {
712 key.offset = other_start;
713 del_slot = path->slots[0];
715 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
716 0, root->root_key.objectid,
717 inode->i_ino, orig_offset);
722 btrfs_set_file_extent_type(leaf, fi,
723 BTRFS_FILE_EXTENT_REG);
727 fi = btrfs_item_ptr(leaf, del_slot - 1,
728 struct btrfs_file_extent_item);
729 btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
730 btrfs_set_file_extent_num_bytes(leaf, fi,
731 extent_end - key.offset);
732 btrfs_mark_buffer_dirty(leaf);
734 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
737 } else if (split == start) {
738 if (locked_end < extent_end) {
739 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
740 locked_end, extent_end - 1, GFP_NOFS);
742 btrfs_release_path(root, path);
743 lock_extent(&BTRFS_I(inode)->io_tree,
744 locked_end, extent_end - 1, GFP_NOFS);
745 locked_end = extent_end;
748 locked_end = extent_end;
750 btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
752 BUG_ON(key.offset != start);
754 btrfs_set_file_extent_offset(leaf, fi, key.offset -
756 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
757 btrfs_set_item_key_safe(trans, root, path, &key);
761 if (extent_end == end) {
763 extent_type = BTRFS_FILE_EXTENT_REG;
765 if (extent_end == end && split == start) {
768 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
769 bytenr, &other_start, &other_end)) {
771 fi = btrfs_item_ptr(leaf, path->slots[0],
772 struct btrfs_file_extent_item);
774 btrfs_set_item_key_safe(trans, root, path, &key);
775 btrfs_set_file_extent_offset(leaf, fi, key.offset -
777 btrfs_set_file_extent_num_bytes(leaf, fi,
782 if (extent_end == end && split == end) {
785 if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino,
786 bytenr, &other_start, &other_end)) {
788 fi = btrfs_item_ptr(leaf, path->slots[0],
789 struct btrfs_file_extent_item);
790 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end -
796 btrfs_mark_buffer_dirty(leaf);
798 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
799 root->root_key.objectid,
800 inode->i_ino, orig_offset);
802 btrfs_release_path(root, path);
805 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi));
808 leaf = path->nodes[0];
809 fi = btrfs_item_ptr(leaf, path->slots[0],
810 struct btrfs_file_extent_item);
811 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
812 btrfs_set_file_extent_type(leaf, fi, extent_type);
813 btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr);
814 btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
815 btrfs_set_file_extent_offset(leaf, fi, key.offset - orig_offset);
816 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset);
817 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
818 btrfs_set_file_extent_compression(leaf, fi, 0);
819 btrfs_set_file_extent_encryption(leaf, fi, 0);
820 btrfs_set_file_extent_other_encoding(leaf, fi, 0);
822 btrfs_mark_buffer_dirty(leaf);
825 btrfs_release_path(root, path);
826 if (split_end && split == start) {
830 if (locked_end > end) {
831 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
834 btrfs_free_path(path);
839 * this gets pages into the page cache and locks them down, it also properly
840 * waits for data=ordered extents to finish before allowing the pages to be
843 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
844 struct page **pages, size_t num_pages,
845 loff_t pos, unsigned long first_index,
846 unsigned long last_index, size_t write_bytes)
849 unsigned long index = pos >> PAGE_CACHE_SHIFT;
850 struct inode *inode = fdentry(file)->d_inode;
855 start_pos = pos & ~((u64)root->sectorsize - 1);
856 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
858 if (start_pos > inode->i_size) {
859 err = btrfs_cont_expand(inode, start_pos);
864 memset(pages, 0, num_pages * sizeof(struct page *));
866 for (i = 0; i < num_pages; i++) {
867 pages[i] = grab_cache_page(inode->i_mapping, index + i);
872 wait_on_page_writeback(pages[i]);
874 if (start_pos < inode->i_size) {
875 struct btrfs_ordered_extent *ordered;
876 lock_extent(&BTRFS_I(inode)->io_tree,
877 start_pos, last_pos - 1, GFP_NOFS);
878 ordered = btrfs_lookup_first_ordered_extent(inode,
881 ordered->file_offset + ordered->len > start_pos &&
882 ordered->file_offset < last_pos) {
883 btrfs_put_ordered_extent(ordered);
884 unlock_extent(&BTRFS_I(inode)->io_tree,
885 start_pos, last_pos - 1, GFP_NOFS);
886 for (i = 0; i < num_pages; i++) {
887 unlock_page(pages[i]);
888 page_cache_release(pages[i]);
890 btrfs_wait_ordered_range(inode, start_pos,
891 last_pos - start_pos);
895 btrfs_put_ordered_extent(ordered);
897 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
898 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
900 unlock_extent(&BTRFS_I(inode)->io_tree,
901 start_pos, last_pos - 1, GFP_NOFS);
903 for (i = 0; i < num_pages; i++) {
904 clear_page_dirty_for_io(pages[i]);
905 set_page_extent_mapped(pages[i]);
906 WARN_ON(!PageLocked(pages[i]));
911 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
912 size_t count, loff_t *ppos)
916 ssize_t num_written = 0;
919 struct inode *inode = fdentry(file)->d_inode;
920 struct btrfs_root *root = BTRFS_I(inode)->root;
921 struct page **pages = NULL;
923 struct page *pinned[2];
924 unsigned long first_index;
925 unsigned long last_index;
928 will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) ||
929 (file->f_flags & O_DIRECT));
931 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
932 PAGE_CACHE_SIZE / (sizeof(struct page *)));
939 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
940 current->backing_dev_info = inode->i_mapping->backing_dev_info;
941 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
947 err = file_remove_suid(file);
950 file_update_time(file);
952 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
954 mutex_lock(&inode->i_mutex);
955 BTRFS_I(inode)->sequence++;
956 first_index = pos >> PAGE_CACHE_SHIFT;
957 last_index = (pos + count) >> PAGE_CACHE_SHIFT;
960 * there are lots of better ways to do this, but this code
961 * makes sure the first and last page in the file range are
962 * up to date and ready for cow
964 if ((pos & (PAGE_CACHE_SIZE - 1))) {
965 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
966 if (!PageUptodate(pinned[0])) {
967 ret = btrfs_readpage(NULL, pinned[0]);
969 wait_on_page_locked(pinned[0]);
971 unlock_page(pinned[0]);
974 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
975 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
976 if (!PageUptodate(pinned[1])) {
977 ret = btrfs_readpage(NULL, pinned[1]);
979 wait_on_page_locked(pinned[1]);
981 unlock_page(pinned[1]);
986 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
987 size_t write_bytes = min(count, nrptrs *
988 (size_t)PAGE_CACHE_SIZE -
990 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
993 WARN_ON(num_pages > nrptrs);
994 memset(pages, 0, sizeof(struct page *) * nrptrs);
996 ret = btrfs_check_data_free_space(root, inode, write_bytes);
1000 ret = prepare_pages(root, file, pages, num_pages,
1001 pos, first_index, last_index,
1004 btrfs_free_reserved_data_space(root, inode,
1009 ret = btrfs_copy_from_user(pos, num_pages,
1010 write_bytes, pages, buf);
1012 btrfs_free_reserved_data_space(root, inode,
1014 btrfs_drop_pages(pages, num_pages);
1018 ret = dirty_and_release_pages(NULL, root, file, pages,
1019 num_pages, pos, write_bytes);
1020 btrfs_drop_pages(pages, num_pages);
1022 btrfs_free_reserved_data_space(root, inode,
1028 btrfs_fdatawrite_range(inode->i_mapping, pos,
1029 pos + write_bytes - 1,
1032 balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1035 (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1036 btrfs_btree_balance_dirty(root, 1);
1037 btrfs_throttle(root);
1041 count -= write_bytes;
1043 num_written += write_bytes;
1048 mutex_unlock(&inode->i_mutex);
1055 page_cache_release(pinned[0]);
1057 page_cache_release(pinned[1]);
1061 * we want to make sure fsync finds this change
1062 * but we haven't joined a transaction running right now.
1064 * Later on, someone is sure to update the inode and get the
1065 * real transid recorded.
1067 * We set last_trans now to the fs_info generation + 1,
1068 * this will either be one more than the running transaction
1069 * or the generation used for the next transaction if there isn't
1070 * one running right now.
1072 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1074 if (num_written > 0 && will_write) {
1075 struct btrfs_trans_handle *trans;
1077 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1081 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
1082 trans = btrfs_start_transaction(root, 1);
1083 ret = btrfs_log_dentry_safe(trans, root,
1086 ret = btrfs_sync_log(trans, root);
1088 btrfs_end_transaction(trans, root);
1090 btrfs_commit_transaction(trans, root);
1092 btrfs_commit_transaction(trans, root);
1095 if (file->f_flags & O_DIRECT) {
1096 invalidate_mapping_pages(inode->i_mapping,
1097 start_pos >> PAGE_CACHE_SHIFT,
1098 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1101 current->backing_dev_info = NULL;
1102 return num_written ? num_written : err;
1105 int btrfs_release_file(struct inode *inode, struct file *filp)
1108 * ordered_data_close is set by settattr when we are about to truncate
1109 * a file from a non-zero size to a zero size. This tries to
1110 * flush down new bytes that may have been written if the
1111 * application were using truncate to replace a file in place.
1113 if (BTRFS_I(inode)->ordered_data_close) {
1114 BTRFS_I(inode)->ordered_data_close = 0;
1115 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1116 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1117 filemap_flush(inode->i_mapping);
1119 if (filp->private_data)
1120 btrfs_ioctl_trans_end(filp);
1125 * fsync call for both files and directories. This logs the inode into
1126 * the tree log instead of forcing full commits whenever possible.
1128 * It needs to call filemap_fdatawait so that all ordered extent updates are
1129 * in the metadata btree are up to date for copying to the log.
1131 * It drops the inode mutex before doing the tree log commit. This is an
1132 * important optimization for directories because holding the mutex prevents
1133 * new operations on the dir while we write to disk.
1135 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
1137 struct inode *inode = dentry->d_inode;
1138 struct btrfs_root *root = BTRFS_I(inode)->root;
1140 struct btrfs_trans_handle *trans;
1143 * check the transaction that last modified this inode
1144 * and see if its already been committed
1146 if (!BTRFS_I(inode)->last_trans)
1149 mutex_lock(&root->fs_info->trans_mutex);
1150 if (BTRFS_I(inode)->last_trans <=
1151 root->fs_info->last_trans_committed) {
1152 BTRFS_I(inode)->last_trans = 0;
1153 mutex_unlock(&root->fs_info->trans_mutex);
1156 mutex_unlock(&root->fs_info->trans_mutex);
1159 filemap_fdatawrite(inode->i_mapping);
1160 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1163 if (datasync && !(inode->i_state & I_DIRTY_PAGES))
1166 * ok we haven't committed the transaction yet, lets do a commit
1168 if (file && file->private_data)
1169 btrfs_ioctl_trans_end(file);
1171 trans = btrfs_start_transaction(root, 1);
1177 ret = btrfs_log_dentry_safe(trans, root, dentry);
1181 /* we've logged all the items and now have a consistent
1182 * version of the file in the log. It is possible that
1183 * someone will come in and modify the file, but that's
1184 * fine because the log is consistent on disk, and we
1185 * have references to all of the file's extents
1187 * It is possible that someone will come in and log the
1188 * file again, but that will end up using the synchronization
1189 * inside btrfs_sync_log to keep things safe.
1191 mutex_unlock(&dentry->d_inode->i_mutex);
1194 ret = btrfs_commit_transaction(trans, root);
1196 ret = btrfs_sync_log(trans, root);
1198 ret = btrfs_end_transaction(trans, root);
1200 ret = btrfs_commit_transaction(trans, root);
1202 mutex_lock(&dentry->d_inode->i_mutex);
1204 return ret > 0 ? EIO : ret;
1207 static struct vm_operations_struct btrfs_file_vm_ops = {
1208 .fault = filemap_fault,
1209 .page_mkwrite = btrfs_page_mkwrite,
1212 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1214 vma->vm_ops = &btrfs_file_vm_ops;
1215 file_accessed(filp);
1219 struct file_operations btrfs_file_operations = {
1220 .llseek = generic_file_llseek,
1221 .read = do_sync_read,
1222 .aio_read = generic_file_aio_read,
1223 .splice_read = generic_file_splice_read,
1224 .write = btrfs_file_write,
1225 .mmap = btrfs_file_mmap,
1226 .open = generic_file_open,
1227 .release = btrfs_release_file,
1228 .fsync = btrfs_sync_file,
1229 .unlocked_ioctl = btrfs_ioctl,
1230 #ifdef CONFIG_COMPAT
1231 .compat_ioctl = btrfs_ioctl,