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.
19 #include <linux/buffer_head.h>
21 #include <linux/pagemap.h>
22 #include <linux/highmem.h>
23 #include <linux/time.h>
24 #include <linux/init.h>
25 #include <linux/string.h>
26 #include <linux/smp_lock.h>
27 #include <linux/backing-dev.h>
28 #include <linux/mpage.h>
29 #include <linux/swap.h>
30 #include <linux/writeback.h>
31 #include <linux/statfs.h>
32 #include <linux/compat.h>
33 #include <linux/version.h>
36 #include "transaction.h"
37 #include "btrfs_inode.h"
39 #include "print-tree.h"
42 static int btrfs_copy_from_user(loff_t pos, int num_pages, int write_bytes,
43 struct page **prepared_pages,
44 const char __user * buf)
48 int offset = pos & (PAGE_CACHE_SIZE - 1);
50 for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
51 size_t count = min_t(size_t,
52 PAGE_CACHE_SIZE - offset, write_bytes);
53 struct page *page = prepared_pages[i];
54 fault_in_pages_readable(buf, count);
56 /* Copy data from userspace to the current page */
58 page_fault = __copy_from_user(page_address(page) + offset,
60 /* Flush processor's dcache for this page */
61 flush_dcache_page(page);
69 return page_fault ? -EFAULT : 0;
72 static void btrfs_drop_pages(struct page **pages, size_t num_pages)
75 for (i = 0; i < num_pages; i++) {
78 unlock_page(pages[i]);
79 mark_page_accessed(pages[i]);
80 page_cache_release(pages[i]);
84 static int insert_inline_extent(struct btrfs_root *root, struct inode *inode,
85 u64 offset, ssize_t size,
86 struct buffer_head *bh)
89 struct btrfs_path *path;
91 struct btrfs_trans_handle *trans;
92 struct btrfs_file_extent_item *ei;
97 path = btrfs_alloc_path();
101 mutex_lock(&root->fs_info->fs_mutex);
102 trans = btrfs_start_transaction(root, 1);
103 btrfs_set_trans_block_group(trans, inode);
105 key.objectid = inode->i_ino;
108 btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
109 BUG_ON(size >= PAGE_CACHE_SIZE);
110 datasize = btrfs_file_extent_calc_inline_size(size);
112 ret = btrfs_insert_empty_item(trans, root, path, &key,
118 ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
119 path->slots[0], struct btrfs_file_extent_item);
120 btrfs_set_file_extent_generation(ei, trans->transid);
121 btrfs_set_file_extent_type(ei,
122 BTRFS_FILE_EXTENT_INLINE);
123 ptr = btrfs_file_extent_inline_start(ei);
125 kaddr = kmap_atomic(bh->b_page, KM_USER0);
126 btrfs_memcpy(root, path->nodes[0]->b_data,
127 ptr, kaddr + bh_offset(bh),
129 kunmap_atomic(kaddr, KM_USER0);
130 btrfs_mark_buffer_dirty(path->nodes[0]);
132 btrfs_free_path(path);
133 ret = btrfs_end_transaction(trans, root);
136 mutex_unlock(&root->fs_info->fs_mutex);
140 static int dirty_and_release_pages(struct btrfs_trans_handle *trans,
141 struct btrfs_root *root,
153 struct inode *inode = file->f_path.dentry->d_inode;
154 struct buffer_head *bh;
156 for (i = 0; i < num_pages; i++) {
157 offset = pos & (PAGE_CACHE_SIZE -1);
158 this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes);
160 /* FIXME, one block at a time */
161 bh = page_buffers(pages[i]);
163 if (buffer_mapped(bh) && bh->b_blocknr == 0) {
164 ret = insert_inline_extent(root, inode,
165 pages[i]->index << PAGE_CACHE_SHIFT,
166 offset + this_write, bh);
173 ret = btrfs_commit_write(file, pages[i], offset,
174 offset + this_write);
180 WARN_ON(this_write > write_bytes);
181 write_bytes -= this_write;
188 * this is very complex, but the basic idea is to drop all extents
189 * in the range start - end. hint_block is filled in with a block number
190 * that would be a good hint to the block allocator for this file.
192 * If an extent intersects the range but is not entirely inside the range
193 * it is either truncated or split. Anything entirely inside the range
194 * is deleted from the tree.
196 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
197 struct btrfs_root *root, struct inode *inode,
198 u64 start, u64 end, u64 *hint_block)
201 struct btrfs_key key;
202 struct btrfs_leaf *leaf;
204 struct btrfs_file_extent_item *extent;
207 struct btrfs_file_extent_item old;
208 struct btrfs_path *path;
209 u64 search_start = start;
216 path = btrfs_alloc_path();
221 btrfs_release_path(root, path);
222 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
227 if (path->slots[0] == 0) {
239 leaf = btrfs_buffer_leaf(path->nodes[0]);
240 slot = path->slots[0];
242 btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
243 if (key.offset >= end || key.objectid != inode->i_ino) {
246 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY) {
250 search_start = key.offset;
253 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
254 extent = btrfs_item_ptr(leaf, slot,
255 struct btrfs_file_extent_item);
256 found_type = btrfs_file_extent_type(extent);
257 if (found_type == BTRFS_FILE_EXTENT_REG) {
258 extent_end = key.offset +
259 (btrfs_file_extent_num_blocks(extent) <<
262 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
264 extent_end = key.offset +
265 btrfs_file_extent_inline_len(leaf->items +
269 extent_end = search_start;
272 /* we found nothing we can drop */
273 if ((!found_extent && !found_inline) ||
274 search_start >= extent_end) {
277 nritems = btrfs_header_nritems(
278 btrfs_buffer_header(path->nodes[0]));
279 if (slot >= nritems - 1) {
280 nextret = btrfs_next_leaf(root, path);
290 /* FIXME, there's only one inline extent allowed right now */
292 u64 mask = root->blocksize - 1;
293 search_start = (extent_end + mask) & ~mask;
295 search_start = extent_end;
297 if (end < extent_end && end >= key.offset) {
300 btrfs_file_extent_disk_blocknr(extent);
301 u64 disk_num_blocks =
302 btrfs_file_extent_disk_num_blocks(extent);
303 memcpy(&old, extent, sizeof(old));
304 if (disk_blocknr != 0) {
305 ret = btrfs_inc_extent_ref(trans, root,
306 disk_blocknr, disk_num_blocks);
310 WARN_ON(found_inline);
313 /* truncate existing extent */
314 if (start > key.offset) {
318 WARN_ON(start & (root->blocksize - 1));
320 new_num = (start - key.offset) >>
322 old_num = btrfs_file_extent_num_blocks(extent);
324 btrfs_file_extent_disk_blocknr(extent);
325 if (btrfs_file_extent_disk_blocknr(extent)) {
327 (old_num - new_num) << 3;
329 btrfs_set_file_extent_num_blocks(extent,
331 btrfs_mark_buffer_dirty(path->nodes[0]);
336 /* delete the entire extent */
338 u64 disk_blocknr = 0;
339 u64 disk_num_blocks = 0;
340 u64 extent_num_blocks = 0;
343 btrfs_file_extent_disk_blocknr(extent);
345 btrfs_file_extent_disk_num_blocks(extent);
347 btrfs_file_extent_num_blocks(extent);
349 btrfs_file_extent_disk_blocknr(extent);
351 ret = btrfs_del_item(trans, root, path);
352 /* TODO update progress marker and return */
354 btrfs_release_path(root, path);
356 if (found_extent && disk_blocknr != 0) {
357 inode->i_blocks -= extent_num_blocks << 3;
358 ret = btrfs_free_extent(trans, root,
364 if (!bookend && search_start >= end) {
371 /* create bookend, splitting the extent in two */
372 if (bookend && found_extent) {
373 struct btrfs_key ins;
374 ins.objectid = inode->i_ino;
377 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
378 btrfs_release_path(root, path);
379 ret = btrfs_insert_empty_item(trans, root, path, &ins,
383 btrfs_print_leaf(root, btrfs_buffer_leaf(path->nodes[0]));
384 printk("got %d on inserting %Lu %u %Lu start %Lu end %Lu found %Lu %Lu\n", ret , ins.objectid, ins.flags, ins.offset, start, end, key.offset, extent_end);
387 extent = btrfs_item_ptr(
388 btrfs_buffer_leaf(path->nodes[0]),
390 struct btrfs_file_extent_item);
391 btrfs_set_file_extent_disk_blocknr(extent,
392 btrfs_file_extent_disk_blocknr(&old));
393 btrfs_set_file_extent_disk_num_blocks(extent,
394 btrfs_file_extent_disk_num_blocks(&old));
396 btrfs_set_file_extent_offset(extent,
397 btrfs_file_extent_offset(&old) +
398 ((end - key.offset) >> inode->i_blkbits));
399 WARN_ON(btrfs_file_extent_num_blocks(&old) <
400 (extent_end - end) >> inode->i_blkbits);
401 btrfs_set_file_extent_num_blocks(extent,
402 (extent_end - end) >> inode->i_blkbits);
404 btrfs_set_file_extent_type(extent,
405 BTRFS_FILE_EXTENT_REG);
406 btrfs_set_file_extent_generation(extent,
407 btrfs_file_extent_generation(&old));
408 btrfs_mark_buffer_dirty(path->nodes[0]);
409 if (btrfs_file_extent_disk_blocknr(&old) != 0) {
411 btrfs_file_extent_num_blocks(extent) << 3;
418 btrfs_free_path(path);
423 * this gets pages into the page cache and locks them down
425 static int prepare_pages(struct btrfs_root *root,
430 unsigned long first_index,
431 unsigned long last_index,
435 unsigned long index = pos >> PAGE_CACHE_SHIFT;
436 struct inode *inode = file->f_path.dentry->d_inode;
440 struct buffer_head *bh;
441 struct buffer_head *head;
442 loff_t isize = i_size_read(inode);
443 struct btrfs_trans_handle *trans;
446 u64 alloc_extent_start;
448 struct btrfs_key ins;
450 start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1);
451 num_blocks = (write_bytes + pos - start_pos + root->blocksize - 1) >>
454 memset(pages, 0, num_pages * sizeof(struct page *));
456 for (i = 0; i < num_pages; i++) {
457 pages[i] = grab_cache_page(inode->i_mapping, index + i);
462 cancel_dirty_page(pages[i], PAGE_CACHE_SIZE);
463 wait_on_page_writeback(pages[i]);
466 mutex_lock(&root->fs_info->fs_mutex);
467 trans = btrfs_start_transaction(root, 1);
470 mutex_unlock(&root->fs_info->fs_mutex);
473 btrfs_set_trans_block_group(trans, inode);
474 /* FIXME blocksize != 4096 */
475 inode->i_blocks += num_blocks << 3;
478 /* FIXME...EIEIO, ENOSPC and more */
480 /* step one, delete the existing extents in this range */
481 /* FIXME blocksize != pagesize */
482 if (start_pos < inode->i_size) {
483 err = btrfs_drop_extents(trans, root, inode,
484 start_pos, (pos + write_bytes + root->blocksize -1) &
485 ~((u64)root->blocksize - 1), &hint_block);
490 /* insert any holes we need to create */
491 if (inode->i_size < start_pos) {
492 u64 last_pos_in_file;
494 u64 mask = root->blocksize - 1;
495 last_pos_in_file = (isize + mask) & ~mask;
496 hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
497 hole_size >>= inode->i_blkbits;
498 if (last_pos_in_file < start_pos) {
499 err = btrfs_insert_file_extent(trans, root,
509 * either allocate an extent for the new bytes or setup the key
510 * to show we are doing inline data in the extent
512 if (isize >= PAGE_CACHE_SIZE || pos + write_bytes < inode->i_size ||
513 pos + write_bytes - start_pos > BTRFS_MAX_INLINE_DATA_SIZE(root)) {
514 err = btrfs_alloc_extent(trans, root, inode->i_ino,
515 num_blocks, 0, hint_block, (u64)-1,
518 goto failed_truncate;
519 err = btrfs_insert_file_extent(trans, root, inode->i_ino,
520 start_pos, ins.objectid, ins.offset,
523 goto failed_truncate;
529 alloc_extent_start = ins.objectid;
530 err = btrfs_end_transaction(trans, root);
531 mutex_unlock(&root->fs_info->fs_mutex);
533 for (i = 0; i < num_pages; i++) {
534 offset = pos & (PAGE_CACHE_SIZE -1);
535 this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes);
536 if (!page_has_buffers(pages[i])) {
537 create_empty_buffers(pages[i],
538 root->fs_info->sb->s_blocksize,
541 head = page_buffers(pages[i]);
544 err = btrfs_map_bh_to_logical(root, bh,
548 goto failed_truncate;
549 bh = bh->b_this_page;
550 if (alloc_extent_start)
551 alloc_extent_start++;
552 } while (bh != head);
554 WARN_ON(this_write > write_bytes);
555 write_bytes -= this_write;
560 btrfs_drop_pages(pages, num_pages);
564 btrfs_drop_pages(pages, num_pages);
566 vmtruncate(inode, isize);
570 mutex_unlock(&root->fs_info->fs_mutex);
575 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
576 size_t count, loff_t *ppos)
579 size_t num_written = 0;
582 struct inode *inode = file->f_path.dentry->d_inode;
583 struct btrfs_root *root = BTRFS_I(inode)->root;
584 struct page **pages = NULL;
586 struct page *pinned[2];
587 unsigned long first_index;
588 unsigned long last_index;
590 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
591 PAGE_CACHE_SIZE / (sizeof(struct page *)));
594 if (file->f_flags & O_DIRECT)
597 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
598 current->backing_dev_info = inode->i_mapping->backing_dev_info;
599 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
604 err = remove_suid(file->f_path.dentry);
607 file_update_time(file);
609 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
611 mutex_lock(&inode->i_mutex);
612 first_index = pos >> PAGE_CACHE_SHIFT;
613 last_index = (pos + count) >> PAGE_CACHE_SHIFT;
616 * there are lots of better ways to do this, but this code
617 * makes sure the first and last page in the file range are
618 * up to date and ready for cow
620 if ((pos & (PAGE_CACHE_SIZE - 1))) {
621 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
622 if (!PageUptodate(pinned[0])) {
623 ret = btrfs_readpage(NULL, pinned[0]);
625 wait_on_page_locked(pinned[0]);
627 unlock_page(pinned[0]);
630 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
631 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
632 if (!PageUptodate(pinned[1])) {
633 ret = btrfs_readpage(NULL, pinned[1]);
635 wait_on_page_locked(pinned[1]);
637 unlock_page(pinned[1]);
642 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
643 size_t write_bytes = min(count, nrptrs *
644 (size_t)PAGE_CACHE_SIZE -
646 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
649 WARN_ON(num_pages > nrptrs);
650 memset(pages, 0, sizeof(pages));
651 ret = prepare_pages(root, file, pages, num_pages,
652 pos, first_index, last_index,
657 ret = btrfs_copy_from_user(pos, num_pages,
658 write_bytes, pages, buf);
660 btrfs_drop_pages(pages, num_pages);
664 ret = dirty_and_release_pages(NULL, root, file, pages,
665 num_pages, pos, write_bytes);
666 btrfs_drop_pages(pages, num_pages);
671 count -= write_bytes;
673 num_written += write_bytes;
675 balance_dirty_pages_ratelimited_nr(inode->i_mapping, num_pages);
676 btrfs_btree_balance_dirty(root);
679 mutex_unlock(&inode->i_mutex);
683 page_cache_release(pinned[0]);
685 page_cache_release(pinned[1]);
687 current->backing_dev_info = NULL;
688 mark_inode_dirty(inode);
689 return num_written ? num_written : err;
692 static int btrfs_sync_file(struct file *file,
693 struct dentry *dentry, int datasync)
695 struct inode *inode = dentry->d_inode;
696 struct btrfs_root *root = BTRFS_I(inode)->root;
698 struct btrfs_trans_handle *trans;
701 * check the transaction that last modified this inode
702 * and see if its already been committed
704 mutex_lock(&root->fs_info->fs_mutex);
705 if (!BTRFS_I(inode)->last_trans)
707 mutex_lock(&root->fs_info->trans_mutex);
708 if (BTRFS_I(inode)->last_trans <=
709 root->fs_info->last_trans_committed) {
710 BTRFS_I(inode)->last_trans = 0;
711 mutex_unlock(&root->fs_info->trans_mutex);
714 mutex_unlock(&root->fs_info->trans_mutex);
717 * ok we haven't committed the transaction yet, lets do a commit
719 trans = btrfs_start_transaction(root, 1);
724 ret = btrfs_commit_transaction(trans, root);
726 mutex_unlock(&root->fs_info->fs_mutex);
727 return ret > 0 ? EIO : ret;
730 static struct vm_operations_struct btrfs_file_vm_ops = {
731 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
732 .nopage = filemap_nopage,
733 .populate = filemap_populate,
735 .fault = filemap_fault,
737 .page_mkwrite = btrfs_page_mkwrite,
740 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
742 vma->vm_ops = &btrfs_file_vm_ops;
747 struct file_operations btrfs_file_operations = {
748 .llseek = generic_file_llseek,
749 .read = do_sync_read,
750 .aio_read = generic_file_aio_read,
751 .write = btrfs_file_write,
752 .mmap = btrfs_file_mmap,
753 .open = generic_file_open,
754 .ioctl = btrfs_ioctl,
755 .fsync = btrfs_sync_file,
757 .compat_ioctl = btrfs_compat_ioctl,