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/falloc.h>
28 #include <linux/swap.h>
29 #include <linux/writeback.h>
30 #include <linux/statfs.h>
31 #include <linux/compat.h>
32 #include <linux/slab.h>
35 #include "transaction.h"
36 #include "btrfs_inode.h"
38 #include "print-tree.h"
44 /* simple helper to fault in pages and copy. This should go away
45 * and be replaced with calls into generic code.
47 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
49 struct page **prepared_pages,
54 int offset = pos & (PAGE_CACHE_SIZE - 1);
57 while (write_bytes > 0) {
58 size_t count = min_t(size_t,
59 PAGE_CACHE_SIZE - offset, write_bytes);
60 struct page *page = prepared_pages[pg];
62 * Copy data from userspace to the current page
64 * Disable pagefault to avoid recursive lock since
65 * the pages are already locked
68 copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
71 /* Flush processor's dcache for this page */
72 flush_dcache_page(page);
73 iov_iter_advance(i, copied);
74 write_bytes -= copied;
75 total_copied += copied;
77 /* Return to btrfs_file_aio_write to fault page */
78 if (unlikely(copied == 0)) {
82 if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
93 * unlocks pages after btrfs_file_write is done with them
95 static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages)
98 for (i = 0; i < num_pages; i++) {
101 /* page checked is some magic around finding pages that
102 * have been modified without going through btrfs_set_page_dirty
105 ClearPageChecked(pages[i]);
106 unlock_page(pages[i]);
107 mark_page_accessed(pages[i]);
108 page_cache_release(pages[i]);
113 * after copy_from_user, pages need to be dirtied and we need to make
114 * sure holes are created between the current EOF and the start of
115 * any next extents (if required).
117 * this also makes the decision about creating an inline extent vs
118 * doing real data extents, marking pages dirty and delalloc as required.
120 static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
121 struct btrfs_root *root,
130 struct inode *inode = fdentry(file)->d_inode;
133 u64 end_of_last_block;
134 u64 end_pos = pos + write_bytes;
135 loff_t isize = i_size_read(inode);
137 start_pos = pos & ~((u64)root->sectorsize - 1);
138 num_bytes = (write_bytes + pos - start_pos +
139 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
141 end_of_last_block = start_pos + num_bytes - 1;
142 err = 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
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 write_lock(&em_tree->lock);
191 em = lookup_extent_mapping(em_tree, start, len);
193 write_unlock(&em_tree->lock);
197 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
198 if (testend && em->start + em->len >= start + len) {
200 write_unlock(&em_tree->lock);
203 start = em->start + em->len;
205 len = start + len - (em->start + em->len);
207 write_unlock(&em_tree->lock);
210 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
211 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
212 remove_extent_mapping(em_tree, em);
214 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
216 split->start = em->start;
217 split->len = start - em->start;
218 split->orig_start = em->orig_start;
219 split->block_start = em->block_start;
222 split->block_len = em->block_len;
224 split->block_len = split->len;
226 split->bdev = em->bdev;
227 split->flags = flags;
228 ret = add_extent_mapping(em_tree, split);
230 free_extent_map(split);
234 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
235 testend && em->start + em->len > start + len) {
236 u64 diff = start + len - em->start;
238 split->start = start + len;
239 split->len = em->start + em->len - (start + len);
240 split->bdev = em->bdev;
241 split->flags = flags;
244 split->block_len = em->block_len;
245 split->block_start = em->block_start;
246 split->orig_start = em->orig_start;
248 split->block_len = split->len;
249 split->block_start = em->block_start + diff;
250 split->orig_start = split->start;
253 ret = add_extent_mapping(em_tree, split);
255 free_extent_map(split);
258 write_unlock(&em_tree->lock);
262 /* once for the tree*/
266 free_extent_map(split);
268 free_extent_map(split2);
273 * this is very complex, but the basic idea is to drop all extents
274 * in the range start - end. hint_block is filled in with a block number
275 * that would be a good hint to the block allocator for this file.
277 * If an extent intersects the range but is not entirely inside the range
278 * it is either truncated or split. Anything entirely inside the range
279 * is deleted from the tree.
281 int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
282 u64 start, u64 end, u64 *hint_byte, int drop_cache)
284 struct btrfs_root *root = BTRFS_I(inode)->root;
285 struct extent_buffer *leaf;
286 struct btrfs_file_extent_item *fi;
287 struct btrfs_path *path;
288 struct btrfs_key key;
289 struct btrfs_key new_key;
290 u64 search_start = start;
293 u64 extent_offset = 0;
302 btrfs_drop_extent_cache(inode, start, end - 1, 0);
304 path = btrfs_alloc_path();
310 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
314 if (ret > 0 && path->slots[0] > 0 && search_start == start) {
315 leaf = path->nodes[0];
316 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
317 if (key.objectid == inode->i_ino &&
318 key.type == BTRFS_EXTENT_DATA_KEY)
323 leaf = path->nodes[0];
324 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
326 ret = btrfs_next_leaf(root, path);
333 leaf = path->nodes[0];
337 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
338 if (key.objectid > inode->i_ino ||
339 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
342 fi = btrfs_item_ptr(leaf, path->slots[0],
343 struct btrfs_file_extent_item);
344 extent_type = btrfs_file_extent_type(leaf, fi);
346 if (extent_type == BTRFS_FILE_EXTENT_REG ||
347 extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
348 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
349 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
350 extent_offset = btrfs_file_extent_offset(leaf, fi);
351 extent_end = key.offset +
352 btrfs_file_extent_num_bytes(leaf, fi);
353 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
354 extent_end = key.offset +
355 btrfs_file_extent_inline_len(leaf, fi);
358 extent_end = search_start;
361 if (extent_end <= search_start) {
366 search_start = max(key.offset, start);
368 btrfs_release_path(root, path);
373 * | - range to drop - |
374 * | -------- extent -------- |
376 if (start > key.offset && end < extent_end) {
378 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
380 memcpy(&new_key, &key, sizeof(new_key));
381 new_key.offset = start;
382 ret = btrfs_duplicate_item(trans, root, path,
384 if (ret == -EAGAIN) {
385 btrfs_release_path(root, path);
391 leaf = path->nodes[0];
392 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
393 struct btrfs_file_extent_item);
394 btrfs_set_file_extent_num_bytes(leaf, fi,
397 fi = btrfs_item_ptr(leaf, path->slots[0],
398 struct btrfs_file_extent_item);
400 extent_offset += start - key.offset;
401 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
402 btrfs_set_file_extent_num_bytes(leaf, fi,
404 btrfs_mark_buffer_dirty(leaf);
406 if (disk_bytenr > 0) {
407 ret = btrfs_inc_extent_ref(trans, root,
408 disk_bytenr, num_bytes, 0,
409 root->root_key.objectid,
411 start - extent_offset);
413 *hint_byte = disk_bytenr;
418 * | ---- range to drop ----- |
419 * | -------- extent -------- |
421 if (start <= key.offset && end < extent_end) {
422 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
424 memcpy(&new_key, &key, sizeof(new_key));
425 new_key.offset = end;
426 btrfs_set_item_key_safe(trans, root, path, &new_key);
428 extent_offset += end - key.offset;
429 btrfs_set_file_extent_offset(leaf, fi, extent_offset);
430 btrfs_set_file_extent_num_bytes(leaf, fi,
432 btrfs_mark_buffer_dirty(leaf);
433 if (disk_bytenr > 0) {
434 inode_sub_bytes(inode, end - key.offset);
435 *hint_byte = disk_bytenr;
440 search_start = extent_end;
442 * | ---- range to drop ----- |
443 * | -------- extent -------- |
445 if (start > key.offset && end >= extent_end) {
447 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
449 btrfs_set_file_extent_num_bytes(leaf, fi,
451 btrfs_mark_buffer_dirty(leaf);
452 if (disk_bytenr > 0) {
453 inode_sub_bytes(inode, extent_end - start);
454 *hint_byte = disk_bytenr;
456 if (end == extent_end)
464 * | ---- range to drop ----- |
465 * | ------ extent ------ |
467 if (start <= key.offset && end >= extent_end) {
469 del_slot = path->slots[0];
472 BUG_ON(del_slot + del_nr != path->slots[0]);
476 if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
477 inode_sub_bytes(inode,
478 extent_end - key.offset);
479 extent_end = ALIGN(extent_end,
481 } else if (disk_bytenr > 0) {
482 ret = btrfs_free_extent(trans, root,
483 disk_bytenr, num_bytes, 0,
484 root->root_key.objectid,
485 key.objectid, key.offset -
488 inode_sub_bytes(inode,
489 extent_end - key.offset);
490 *hint_byte = disk_bytenr;
493 if (end == extent_end)
496 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
501 ret = btrfs_del_items(trans, root, path, del_slot,
508 btrfs_release_path(root, path);
516 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
520 btrfs_free_path(path);
524 static int extent_mergeable(struct extent_buffer *leaf, int slot,
525 u64 objectid, u64 bytenr, u64 orig_offset,
526 u64 *start, u64 *end)
528 struct btrfs_file_extent_item *fi;
529 struct btrfs_key key;
532 if (slot < 0 || slot >= btrfs_header_nritems(leaf))
535 btrfs_item_key_to_cpu(leaf, &key, slot);
536 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
539 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
540 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
541 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
542 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
543 btrfs_file_extent_compression(leaf, fi) ||
544 btrfs_file_extent_encryption(leaf, fi) ||
545 btrfs_file_extent_other_encoding(leaf, fi))
548 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
549 if ((*start && *start != key.offset) || (*end && *end != extent_end))
558 * Mark extent in the range start - end as written.
560 * This changes extent type from 'pre-allocated' to 'regular'. If only
561 * part of extent is marked as written, the extent will be split into
564 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
565 struct inode *inode, u64 start, u64 end)
567 struct btrfs_root *root = BTRFS_I(inode)->root;
568 struct extent_buffer *leaf;
569 struct btrfs_path *path;
570 struct btrfs_file_extent_item *fi;
571 struct btrfs_key key;
572 struct btrfs_key new_key;
585 btrfs_drop_extent_cache(inode, start, end - 1, 0);
587 path = btrfs_alloc_path();
592 key.objectid = inode->i_ino;
593 key.type = BTRFS_EXTENT_DATA_KEY;
596 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
597 if (ret > 0 && path->slots[0] > 0)
600 leaf = path->nodes[0];
601 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
602 BUG_ON(key.objectid != inode->i_ino ||
603 key.type != BTRFS_EXTENT_DATA_KEY);
604 fi = btrfs_item_ptr(leaf, path->slots[0],
605 struct btrfs_file_extent_item);
606 BUG_ON(btrfs_file_extent_type(leaf, fi) !=
607 BTRFS_FILE_EXTENT_PREALLOC);
608 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
609 BUG_ON(key.offset > start || extent_end < end);
611 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
612 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
613 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
614 memcpy(&new_key, &key, sizeof(new_key));
616 if (start == key.offset && end < extent_end) {
619 if (extent_mergeable(leaf, path->slots[0] - 1,
620 inode->i_ino, bytenr, orig_offset,
621 &other_start, &other_end)) {
622 new_key.offset = end;
623 btrfs_set_item_key_safe(trans, root, path, &new_key);
624 fi = btrfs_item_ptr(leaf, path->slots[0],
625 struct btrfs_file_extent_item);
626 btrfs_set_file_extent_num_bytes(leaf, fi,
628 btrfs_set_file_extent_offset(leaf, fi,
630 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
631 struct btrfs_file_extent_item);
632 btrfs_set_file_extent_num_bytes(leaf, fi,
634 btrfs_mark_buffer_dirty(leaf);
639 if (start > key.offset && end == extent_end) {
642 if (extent_mergeable(leaf, path->slots[0] + 1,
643 inode->i_ino, bytenr, orig_offset,
644 &other_start, &other_end)) {
645 fi = btrfs_item_ptr(leaf, path->slots[0],
646 struct btrfs_file_extent_item);
647 btrfs_set_file_extent_num_bytes(leaf, fi,
650 new_key.offset = start;
651 btrfs_set_item_key_safe(trans, root, path, &new_key);
653 fi = btrfs_item_ptr(leaf, path->slots[0],
654 struct btrfs_file_extent_item);
655 btrfs_set_file_extent_num_bytes(leaf, fi,
657 btrfs_set_file_extent_offset(leaf, fi,
658 start - orig_offset);
659 btrfs_mark_buffer_dirty(leaf);
664 while (start > key.offset || end < extent_end) {
665 if (key.offset == start)
668 new_key.offset = split;
669 ret = btrfs_duplicate_item(trans, root, path, &new_key);
670 if (ret == -EAGAIN) {
671 btrfs_release_path(root, path);
676 leaf = path->nodes[0];
677 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
678 struct btrfs_file_extent_item);
679 btrfs_set_file_extent_num_bytes(leaf, fi,
682 fi = btrfs_item_ptr(leaf, path->slots[0],
683 struct btrfs_file_extent_item);
685 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
686 btrfs_set_file_extent_num_bytes(leaf, fi,
688 btrfs_mark_buffer_dirty(leaf);
690 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
691 root->root_key.objectid,
692 inode->i_ino, orig_offset);
695 if (split == start) {
698 BUG_ON(start != key.offset);
707 if (extent_mergeable(leaf, path->slots[0] + 1,
708 inode->i_ino, bytenr, orig_offset,
709 &other_start, &other_end)) {
711 btrfs_release_path(root, path);
714 extent_end = other_end;
715 del_slot = path->slots[0] + 1;
717 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
718 0, root->root_key.objectid,
719 inode->i_ino, orig_offset);
724 if (extent_mergeable(leaf, path->slots[0] - 1,
725 inode->i_ino, bytenr, orig_offset,
726 &other_start, &other_end)) {
728 btrfs_release_path(root, path);
731 key.offset = other_start;
732 del_slot = path->slots[0];
734 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
735 0, root->root_key.objectid,
736 inode->i_ino, orig_offset);
740 fi = btrfs_item_ptr(leaf, path->slots[0],
741 struct btrfs_file_extent_item);
742 btrfs_set_file_extent_type(leaf, fi,
743 BTRFS_FILE_EXTENT_REG);
744 btrfs_mark_buffer_dirty(leaf);
746 fi = btrfs_item_ptr(leaf, del_slot - 1,
747 struct btrfs_file_extent_item);
748 btrfs_set_file_extent_type(leaf, fi,
749 BTRFS_FILE_EXTENT_REG);
750 btrfs_set_file_extent_num_bytes(leaf, fi,
751 extent_end - key.offset);
752 btrfs_mark_buffer_dirty(leaf);
754 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
758 btrfs_free_path(path);
763 * this gets pages into the page cache and locks them down, it also properly
764 * waits for data=ordered extents to finish before allowing the pages to be
767 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
768 struct page **pages, size_t num_pages,
769 loff_t pos, unsigned long first_index,
770 unsigned long last_index, size_t write_bytes)
772 struct extent_state *cached_state = NULL;
774 unsigned long index = pos >> PAGE_CACHE_SHIFT;
775 struct inode *inode = fdentry(file)->d_inode;
780 start_pos = pos & ~((u64)root->sectorsize - 1);
781 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
783 if (start_pos > inode->i_size) {
784 err = btrfs_cont_expand(inode, start_pos);
789 memset(pages, 0, num_pages * sizeof(struct page *));
791 for (i = 0; i < num_pages; i++) {
792 pages[i] = grab_cache_page(inode->i_mapping, index + i);
797 wait_on_page_writeback(pages[i]);
799 if (start_pos < inode->i_size) {
800 struct btrfs_ordered_extent *ordered;
801 lock_extent_bits(&BTRFS_I(inode)->io_tree,
802 start_pos, last_pos - 1, 0, &cached_state,
804 ordered = btrfs_lookup_first_ordered_extent(inode,
807 ordered->file_offset + ordered->len > start_pos &&
808 ordered->file_offset < last_pos) {
809 btrfs_put_ordered_extent(ordered);
810 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
811 start_pos, last_pos - 1,
812 &cached_state, GFP_NOFS);
813 for (i = 0; i < num_pages; i++) {
814 unlock_page(pages[i]);
815 page_cache_release(pages[i]);
817 btrfs_wait_ordered_range(inode, start_pos,
818 last_pos - start_pos);
822 btrfs_put_ordered_extent(ordered);
824 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
825 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
826 EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
828 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
829 start_pos, last_pos - 1, &cached_state,
832 for (i = 0; i < num_pages; i++) {
833 clear_page_dirty_for_io(pages[i]);
834 set_page_extent_mapped(pages[i]);
835 WARN_ON(!PageLocked(pages[i]));
840 static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
841 const struct iovec *iov,
842 unsigned long nr_segs, loff_t pos)
844 struct file *file = iocb->ki_filp;
845 struct inode *inode = fdentry(file)->d_inode;
846 struct btrfs_root *root = BTRFS_I(inode)->root;
847 struct page *pinned[2];
848 struct page **pages = NULL;
850 loff_t *ppos = &iocb->ki_pos;
852 ssize_t num_written = 0;
858 unsigned long first_index;
859 unsigned long last_index;
865 will_write = ((file->f_flags & O_DSYNC) || IS_SYNC(inode) ||
866 (file->f_flags & O_DIRECT));
873 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
875 mutex_lock(&inode->i_mutex);
877 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
882 current->backing_dev_info = inode->i_mapping->backing_dev_info;
883 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
890 err = file_remove_suid(file);
894 file_update_time(file);
895 BTRFS_I(inode)->sequence++;
897 if (unlikely(file->f_flags & O_DIRECT)) {
898 num_written = generic_file_direct_write(iocb, iov, &nr_segs,
902 * the generic O_DIRECT will update in-memory i_size after the
903 * DIOs are done. But our endio handlers that update the on
904 * disk i_size never update past the in memory i_size. So we
905 * need one more update here to catch any additions to the
908 if (inode->i_size != BTRFS_I(inode)->disk_i_size) {
909 btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
910 mark_inode_dirty(inode);
913 if (num_written < 0) {
917 } else if (num_written == count) {
918 /* pick up pos changes done by the generic code */
923 * We are going to do buffered for the rest of the range, so we
924 * need to make sure to invalidate the buffered pages when we're
931 iov_iter_init(&i, iov, nr_segs, count, num_written);
932 nrptrs = min((iov_iter_count(&i) + PAGE_CACHE_SIZE - 1) /
933 PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
934 (sizeof(struct page *)));
935 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
937 /* generic_write_checks can change our pos */
940 first_index = pos >> PAGE_CACHE_SHIFT;
941 last_index = (pos + iov_iter_count(&i)) >> PAGE_CACHE_SHIFT;
944 * there are lots of better ways to do this, but this code
945 * makes sure the first and last page in the file range are
946 * up to date and ready for cow
948 if ((pos & (PAGE_CACHE_SIZE - 1))) {
949 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
950 if (!PageUptodate(pinned[0])) {
951 ret = btrfs_readpage(NULL, pinned[0]);
953 wait_on_page_locked(pinned[0]);
955 unlock_page(pinned[0]);
958 if ((pos + iov_iter_count(&i)) & (PAGE_CACHE_SIZE - 1)) {
959 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
960 if (!PageUptodate(pinned[1])) {
961 ret = btrfs_readpage(NULL, pinned[1]);
963 wait_on_page_locked(pinned[1]);
965 unlock_page(pinned[1]);
969 while (iov_iter_count(&i) > 0) {
970 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
971 size_t write_bytes = min(iov_iter_count(&i),
972 nrptrs * (size_t)PAGE_CACHE_SIZE -
974 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
977 WARN_ON(num_pages > nrptrs);
978 memset(pages, 0, sizeof(struct page *) * nrptrs);
981 * Fault pages before locking them in prepare_pages
982 * to avoid recursive lock
984 if (unlikely(iov_iter_fault_in_readable(&i, write_bytes))) {
989 ret = btrfs_delalloc_reserve_space(inode,
990 num_pages << PAGE_CACHE_SHIFT);
994 ret = prepare_pages(root, file, pages, num_pages,
995 pos, first_index, last_index,
998 btrfs_delalloc_release_space(inode,
999 num_pages << PAGE_CACHE_SHIFT);
1003 copied = btrfs_copy_from_user(pos, num_pages,
1004 write_bytes, pages, &i);
1005 dirty_pages = (copied + PAGE_CACHE_SIZE - 1) >>
1008 if (num_pages > dirty_pages) {
1011 &BTRFS_I(inode)->outstanding_extents);
1012 btrfs_delalloc_release_space(inode,
1013 (num_pages - dirty_pages) <<
1018 dirty_and_release_pages(NULL, root, file, pages,
1019 dirty_pages, pos, copied);
1022 btrfs_drop_pages(pages, num_pages);
1026 filemap_fdatawrite_range(inode->i_mapping, pos,
1029 balance_dirty_pages_ratelimited_nr(
1033 (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1034 btrfs_btree_balance_dirty(root, 1);
1035 btrfs_throttle(root);
1040 num_written += copied;
1045 mutex_unlock(&inode->i_mutex);
1051 page_cache_release(pinned[0]);
1053 page_cache_release(pinned[1]);
1057 * we want to make sure fsync finds this change
1058 * but we haven't joined a transaction running right now.
1060 * Later on, someone is sure to update the inode and get the
1061 * real transid recorded.
1063 * We set last_trans now to the fs_info generation + 1,
1064 * this will either be one more than the running transaction
1065 * or the generation used for the next transaction if there isn't
1066 * one running right now.
1068 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1070 if (num_written > 0 && will_write) {
1071 struct btrfs_trans_handle *trans;
1073 err = btrfs_wait_ordered_range(inode, start_pos, num_written);
1077 if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) {
1078 trans = btrfs_start_transaction(root, 0);
1079 if (IS_ERR(trans)) {
1080 num_written = PTR_ERR(trans);
1083 mutex_lock(&inode->i_mutex);
1084 ret = btrfs_log_dentry_safe(trans, root,
1086 mutex_unlock(&inode->i_mutex);
1088 ret = btrfs_sync_log(trans, root);
1090 btrfs_end_transaction(trans, root);
1092 btrfs_commit_transaction(trans, root);
1093 } else if (ret != BTRFS_NO_LOG_SYNC) {
1094 btrfs_commit_transaction(trans, root);
1096 btrfs_end_transaction(trans, root);
1099 if (file->f_flags & O_DIRECT && buffered) {
1100 invalidate_mapping_pages(inode->i_mapping,
1101 start_pos >> PAGE_CACHE_SHIFT,
1102 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1106 current->backing_dev_info = NULL;
1107 return num_written ? num_written : err;
1110 int btrfs_release_file(struct inode *inode, struct file *filp)
1113 * ordered_data_close is set by settattr when we are about to truncate
1114 * a file from a non-zero size to a zero size. This tries to
1115 * flush down new bytes that may have been written if the
1116 * application were using truncate to replace a file in place.
1118 if (BTRFS_I(inode)->ordered_data_close) {
1119 BTRFS_I(inode)->ordered_data_close = 0;
1120 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1121 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1122 filemap_flush(inode->i_mapping);
1124 if (filp->private_data)
1125 btrfs_ioctl_trans_end(filp);
1130 * fsync call for both files and directories. This logs the inode into
1131 * the tree log instead of forcing full commits whenever possible.
1133 * It needs to call filemap_fdatawait so that all ordered extent updates are
1134 * in the metadata btree are up to date for copying to the log.
1136 * It drops the inode mutex before doing the tree log commit. This is an
1137 * important optimization for directories because holding the mutex prevents
1138 * new operations on the dir while we write to disk.
1140 int btrfs_sync_file(struct file *file, int datasync)
1142 struct dentry *dentry = file->f_path.dentry;
1143 struct inode *inode = dentry->d_inode;
1144 struct btrfs_root *root = BTRFS_I(inode)->root;
1146 struct btrfs_trans_handle *trans;
1149 /* we wait first, since the writeback may change the inode */
1151 /* the VFS called filemap_fdatawrite for us */
1152 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1156 * check the transaction that last modified this inode
1157 * and see if its already been committed
1159 if (!BTRFS_I(inode)->last_trans)
1163 * if the last transaction that changed this file was before
1164 * the current transaction, we can bail out now without any
1167 mutex_lock(&root->fs_info->trans_mutex);
1168 if (BTRFS_I(inode)->last_trans <=
1169 root->fs_info->last_trans_committed) {
1170 BTRFS_I(inode)->last_trans = 0;
1171 mutex_unlock(&root->fs_info->trans_mutex);
1174 mutex_unlock(&root->fs_info->trans_mutex);
1177 * ok we haven't committed the transaction yet, lets do a commit
1179 if (file->private_data)
1180 btrfs_ioctl_trans_end(file);
1182 trans = btrfs_start_transaction(root, 0);
1183 if (IS_ERR(trans)) {
1184 ret = PTR_ERR(trans);
1188 ret = btrfs_log_dentry_safe(trans, root, dentry);
1192 /* we've logged all the items and now have a consistent
1193 * version of the file in the log. It is possible that
1194 * someone will come in and modify the file, but that's
1195 * fine because the log is consistent on disk, and we
1196 * have references to all of the file's extents
1198 * It is possible that someone will come in and log the
1199 * file again, but that will end up using the synchronization
1200 * inside btrfs_sync_log to keep things safe.
1202 mutex_unlock(&dentry->d_inode->i_mutex);
1204 if (ret != BTRFS_NO_LOG_SYNC) {
1206 ret = btrfs_commit_transaction(trans, root);
1208 ret = btrfs_sync_log(trans, root);
1210 ret = btrfs_end_transaction(trans, root);
1212 ret = btrfs_commit_transaction(trans, root);
1215 ret = btrfs_end_transaction(trans, root);
1217 mutex_lock(&dentry->d_inode->i_mutex);
1219 return ret > 0 ? -EIO : ret;
1222 static const struct vm_operations_struct btrfs_file_vm_ops = {
1223 .fault = filemap_fault,
1224 .page_mkwrite = btrfs_page_mkwrite,
1227 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1229 struct address_space *mapping = filp->f_mapping;
1231 if (!mapping->a_ops->readpage)
1234 file_accessed(filp);
1235 vma->vm_ops = &btrfs_file_vm_ops;
1236 vma->vm_flags |= VM_CAN_NONLINEAR;
1241 static long btrfs_fallocate(struct file *file, int mode,
1242 loff_t offset, loff_t len)
1244 struct inode *inode = file->f_path.dentry->d_inode;
1245 struct extent_state *cached_state = NULL;
1252 u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
1253 struct extent_map *em;
1256 alloc_start = offset & ~mask;
1257 alloc_end = (offset + len + mask) & ~mask;
1259 /* We only support the FALLOC_FL_KEEP_SIZE mode */
1260 if (mode & ~FALLOC_FL_KEEP_SIZE)
1264 * wait for ordered IO before we have any locks. We'll loop again
1265 * below with the locks held.
1267 btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
1269 mutex_lock(&inode->i_mutex);
1270 ret = inode_newsize_ok(inode, alloc_end);
1274 if (alloc_start > inode->i_size) {
1275 ret = btrfs_cont_expand(inode, alloc_start);
1280 ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
1284 locked_end = alloc_end - 1;
1286 struct btrfs_ordered_extent *ordered;
1288 /* the extent lock is ordered inside the running
1291 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
1292 locked_end, 0, &cached_state, GFP_NOFS);
1293 ordered = btrfs_lookup_first_ordered_extent(inode,
1296 ordered->file_offset + ordered->len > alloc_start &&
1297 ordered->file_offset < alloc_end) {
1298 btrfs_put_ordered_extent(ordered);
1299 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1300 alloc_start, locked_end,
1301 &cached_state, GFP_NOFS);
1303 * we can't wait on the range with the transaction
1304 * running or with the extent lock held
1306 btrfs_wait_ordered_range(inode, alloc_start,
1307 alloc_end - alloc_start);
1310 btrfs_put_ordered_extent(ordered);
1315 cur_offset = alloc_start;
1317 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
1318 alloc_end - cur_offset, 0);
1319 BUG_ON(IS_ERR(em) || !em);
1320 last_byte = min(extent_map_end(em), alloc_end);
1321 last_byte = (last_byte + mask) & ~mask;
1322 if (em->block_start == EXTENT_MAP_HOLE ||
1323 (cur_offset >= inode->i_size &&
1324 !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
1325 ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
1326 last_byte - cur_offset,
1327 1 << inode->i_blkbits,
1331 free_extent_map(em);
1335 free_extent_map(em);
1337 cur_offset = last_byte;
1338 if (cur_offset >= alloc_end) {
1343 unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
1344 &cached_state, GFP_NOFS);
1346 btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
1348 mutex_unlock(&inode->i_mutex);
1352 const struct file_operations btrfs_file_operations = {
1353 .llseek = generic_file_llseek,
1354 .read = do_sync_read,
1355 .write = do_sync_write,
1356 .aio_read = generic_file_aio_read,
1357 .splice_read = generic_file_splice_read,
1358 .aio_write = btrfs_file_aio_write,
1359 .mmap = btrfs_file_mmap,
1360 .open = generic_file_open,
1361 .release = btrfs_release_file,
1362 .fsync = btrfs_sync_file,
1363 .fallocate = btrfs_fallocate,
1364 .unlocked_ioctl = btrfs_ioctl,
1365 #ifdef CONFIG_COMPAT
1366 .compat_ioctl = btrfs_ioctl,