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/module.h>
20 #include <linux/buffer_head.h>
22 #include <linux/pagemap.h>
23 #include <linux/highmem.h>
24 #include <linux/time.h>
25 #include <linux/init.h>
26 #include <linux/string.h>
27 #include <linux/smp_lock.h>
28 #include <linux/backing-dev.h>
29 #include <linux/mpage.h>
30 #include <linux/swap.h>
31 #include <linux/writeback.h>
32 #include <linux/statfs.h>
33 #include <linux/compat.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 dirty_and_release_pages(struct btrfs_trans_handle *trans,
85 struct btrfs_root *root,
97 struct inode *inode = file->f_path.dentry->d_inode;
98 struct buffer_head *bh;
99 struct btrfs_file_extent_item *ei;
101 for (i = 0; i < num_pages; i++) {
102 offset = pos & (PAGE_CACHE_SIZE -1);
103 this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes);
104 /* FIXME, one block at a time */
106 mutex_lock(&root->fs_info->fs_mutex);
107 trans = btrfs_start_transaction(root, 1);
108 btrfs_set_trans_block_group(trans, inode);
110 bh = page_buffers(pages[i]);
112 if (buffer_mapped(bh) && bh->b_blocknr == 0) {
113 struct btrfs_key key;
114 struct btrfs_path *path;
118 /* create an inline extent, and copy the data in */
119 path = btrfs_alloc_path();
121 key.objectid = inode->i_ino;
122 key.offset = pages[i]->index << PAGE_CACHE_SHIFT;
124 btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
125 BUG_ON(write_bytes >= PAGE_CACHE_SIZE);
127 btrfs_file_extent_calc_inline_size(write_bytes);
129 ret = btrfs_insert_empty_item(trans, root, path, &key,
132 ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
133 path->slots[0], struct btrfs_file_extent_item);
134 btrfs_set_file_extent_generation(ei, trans->transid);
135 btrfs_set_file_extent_type(ei,
136 BTRFS_FILE_EXTENT_INLINE);
137 ptr = btrfs_file_extent_inline_start(ei);
138 kaddr = kmap_atomic(bh->b_page, KM_USER0);
139 btrfs_memcpy(root, path->nodes[0]->b_data,
140 ptr, kaddr + bh_offset(bh),
141 offset + write_bytes);
142 kunmap_atomic(kaddr, KM_USER0);
143 mark_buffer_dirty(path->nodes[0]);
144 btrfs_free_path(path);
145 } else if (buffer_mapped(bh)) {
146 /* csum the file data */
147 btrfs_csum_file_block(trans, root, inode->i_ino,
148 pages[i]->index << PAGE_CACHE_SHIFT,
149 kmap(pages[i]), PAGE_CACHE_SIZE);
152 SetPageChecked(pages[i]);
153 ret = btrfs_end_transaction(trans, root);
155 mutex_unlock(&root->fs_info->fs_mutex);
157 ret = btrfs_commit_write(file, pages[i], offset,
158 offset + this_write);
164 WARN_ON(this_write > write_bytes);
165 write_bytes -= this_write;
172 * this is very complex, but the basic idea is to drop all extents
173 * in the range start - end. hint_block is filled in with a block number
174 * that would be a good hint to the block allocator for this file.
176 * If an extent intersects the range but is not entirely inside the range
177 * it is either truncated or split. Anything entirely inside the range
178 * is deleted from the tree.
180 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
181 struct btrfs_root *root, struct inode *inode,
182 u64 start, u64 end, u64 *hint_block)
185 struct btrfs_key key;
186 struct btrfs_leaf *leaf;
188 struct btrfs_file_extent_item *extent;
191 struct btrfs_file_extent_item old;
192 struct btrfs_path *path;
193 u64 search_start = start;
199 path = btrfs_alloc_path();
203 btrfs_release_path(root, path);
204 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
209 if (path->slots[0] == 0) {
220 leaf = btrfs_buffer_leaf(path->nodes[0]);
221 slot = path->slots[0];
222 btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
223 if (key.offset >= end || key.objectid != inode->i_ino) {
227 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY) {
231 extent = btrfs_item_ptr(leaf, slot,
232 struct btrfs_file_extent_item);
233 found_type = btrfs_file_extent_type(extent);
234 if (found_type == BTRFS_FILE_EXTENT_REG) {
235 extent_end = key.offset +
236 (btrfs_file_extent_num_blocks(extent) <<
239 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
241 extent_end = key.offset +
242 btrfs_file_extent_inline_len(leaf->items + slot);
245 /* we found nothing we can drop */
246 if (!found_extent && !found_inline) {
251 /* we found nothing inside the range */
252 if (search_start >= extent_end) {
257 /* FIXME, there's only one inline extent allowed right now */
259 u64 mask = root->blocksize - 1;
260 search_start = (extent_end + mask) & ~mask;
262 search_start = extent_end;
264 if (end < extent_end && end >= key.offset) {
267 btrfs_file_extent_disk_blocknr(extent);
268 u64 disk_num_blocks =
269 btrfs_file_extent_disk_num_blocks(extent);
270 memcpy(&old, extent, sizeof(old));
271 if (disk_blocknr != 0) {
272 ret = btrfs_inc_extent_ref(trans, root,
273 disk_blocknr, disk_num_blocks);
277 WARN_ON(found_inline);
281 /* truncate existing extent */
282 if (start > key.offset) {
286 WARN_ON(start & (root->blocksize - 1));
288 new_num = (start - key.offset) >>
290 old_num = btrfs_file_extent_num_blocks(extent);
292 btrfs_file_extent_disk_blocknr(extent);
293 if (btrfs_file_extent_disk_blocknr(extent)) {
295 (old_num - new_num) << 3;
297 btrfs_set_file_extent_num_blocks(extent,
299 mark_buffer_dirty(path->nodes[0]);
304 /* delete the entire extent */
306 u64 disk_blocknr = 0;
307 u64 disk_num_blocks = 0;
308 u64 extent_num_blocks = 0;
311 btrfs_file_extent_disk_blocknr(extent);
313 btrfs_file_extent_disk_num_blocks(extent);
315 btrfs_file_extent_num_blocks(extent);
317 btrfs_file_extent_disk_blocknr(extent);
319 ret = btrfs_del_item(trans, root, path);
321 btrfs_release_path(root, path);
323 if (found_extent && disk_blocknr != 0) {
324 inode->i_blocks -= extent_num_blocks << 3;
325 ret = btrfs_free_extent(trans, root,
331 if (!bookend && search_start >= end) {
338 /* create bookend, splitting the extent in two */
339 if (bookend && found_extent) {
340 struct btrfs_key ins;
341 ins.objectid = inode->i_ino;
344 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
346 btrfs_release_path(root, path);
347 ret = btrfs_insert_empty_item(trans, root, path, &ins,
350 extent = btrfs_item_ptr(
351 btrfs_buffer_leaf(path->nodes[0]),
353 struct btrfs_file_extent_item);
354 btrfs_set_file_extent_disk_blocknr(extent,
355 btrfs_file_extent_disk_blocknr(&old));
356 btrfs_set_file_extent_disk_num_blocks(extent,
357 btrfs_file_extent_disk_num_blocks(&old));
359 btrfs_set_file_extent_offset(extent,
360 btrfs_file_extent_offset(&old) +
361 ((end - key.offset) >> inode->i_blkbits));
362 WARN_ON(btrfs_file_extent_num_blocks(&old) <
363 (extent_end - end) >> inode->i_blkbits);
364 btrfs_set_file_extent_num_blocks(extent,
365 (extent_end - end) >> inode->i_blkbits);
367 btrfs_set_file_extent_type(extent,
368 BTRFS_FILE_EXTENT_REG);
369 btrfs_set_file_extent_generation(extent,
370 btrfs_file_extent_generation(&old));
371 btrfs_mark_buffer_dirty(path->nodes[0]);
372 if (btrfs_file_extent_disk_blocknr(&old) != 0) {
374 btrfs_file_extent_num_blocks(extent) << 3;
381 btrfs_free_path(path);
386 * this gets pages into the page cache and locks them down
388 static int prepare_pages(struct btrfs_root *root,
393 unsigned long first_index,
394 unsigned long last_index,
396 u64 alloc_extent_start)
399 unsigned long index = pos >> PAGE_CACHE_SHIFT;
400 struct inode *inode = file->f_path.dentry->d_inode;
404 struct buffer_head *bh;
405 struct buffer_head *head;
406 loff_t isize = i_size_read(inode);
408 memset(pages, 0, num_pages * sizeof(struct page *));
410 for (i = 0; i < num_pages; i++) {
411 pages[i] = grab_cache_page(inode->i_mapping, index + i);
416 cancel_dirty_page(pages[i], PAGE_CACHE_SIZE);
417 wait_on_page_writeback(pages[i]);
418 offset = pos & (PAGE_CACHE_SIZE -1);
419 this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes);
420 if (!page_has_buffers(pages[i])) {
421 create_empty_buffers(pages[i],
422 root->fs_info->sb->s_blocksize,
425 head = page_buffers(pages[i]);
428 err = btrfs_map_bh_to_logical(root, bh,
432 goto failed_truncate;
433 bh = bh->b_this_page;
434 if (alloc_extent_start)
435 alloc_extent_start++;
436 } while (bh != head);
438 WARN_ON(this_write > write_bytes);
439 write_bytes -= this_write;
444 btrfs_drop_pages(pages, num_pages);
448 btrfs_drop_pages(pages, num_pages);
450 vmtruncate(inode, isize);
454 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
455 size_t count, loff_t *ppos)
458 size_t num_written = 0;
461 struct inode *inode = file->f_path.dentry->d_inode;
462 struct btrfs_root *root = BTRFS_I(inode)->root;
463 struct page *pages[8];
464 struct page *pinned[2];
465 unsigned long first_index;
466 unsigned long last_index;
469 u64 alloc_extent_start;
471 struct btrfs_trans_handle *trans;
472 struct btrfs_key ins;
475 if (file->f_flags & O_DIRECT)
478 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
479 current->backing_dev_info = inode->i_mapping->backing_dev_info;
480 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
485 err = remove_suid(file->f_path.dentry);
488 file_update_time(file);
490 start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1);
491 num_blocks = (count + pos - start_pos + root->blocksize - 1) >>
494 mutex_lock(&inode->i_mutex);
495 first_index = pos >> PAGE_CACHE_SHIFT;
496 last_index = (pos + count) >> PAGE_CACHE_SHIFT;
499 * there are lots of better ways to do this, but this code
500 * makes sure the first and last page in the file range are
501 * up to date and ready for cow
503 if ((pos & (PAGE_CACHE_SIZE - 1))) {
504 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
505 if (!PageUptodate(pinned[0])) {
506 ret = mpage_readpage(pinned[0], btrfs_get_block);
508 wait_on_page_locked(pinned[0]);
510 unlock_page(pinned[0]);
513 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
514 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
515 if (!PageUptodate(pinned[1])) {
516 ret = mpage_readpage(pinned[1], btrfs_get_block);
518 wait_on_page_locked(pinned[1]);
520 unlock_page(pinned[1]);
524 mutex_lock(&root->fs_info->fs_mutex);
525 trans = btrfs_start_transaction(root, 1);
528 mutex_unlock(&root->fs_info->fs_mutex);
531 btrfs_set_trans_block_group(trans, inode);
532 /* FIXME blocksize != 4096 */
533 inode->i_blocks += num_blocks << 3;
536 /* FIXME...EIEIO, ENOSPC and more */
538 /* step one, delete the existing extents in this range */
539 if (start_pos < inode->i_size) {
540 /* FIXME blocksize != pagesize */
541 ret = btrfs_drop_extents(trans, root, inode,
543 (pos + count + root->blocksize -1) &
544 ~((u64)root->blocksize - 1),
549 /* insert any holes we need to create */
550 if (inode->i_size < start_pos) {
551 u64 last_pos_in_file;
553 u64 mask = root->blocksize - 1;
554 last_pos_in_file = (inode->i_size + mask) & ~mask;
555 hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
556 hole_size >>= inode->i_blkbits;
557 if (last_pos_in_file < start_pos) {
558 ret = btrfs_insert_file_extent(trans, root,
567 * either allocate an extent for the new bytes or setup the key
568 * to show we are doing inline data in the extent
570 if (inode->i_size >= PAGE_CACHE_SIZE || pos + count < inode->i_size ||
571 pos + count - start_pos > BTRFS_MAX_INLINE_DATA_SIZE(root)) {
572 ret = btrfs_alloc_extent(trans, root, inode->i_ino,
573 num_blocks, hint_block, (u64)-1,
576 ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
577 start_pos, ins.objectid, ins.offset,
585 alloc_extent_start = ins.objectid;
586 ret = btrfs_end_transaction(trans, root);
587 mutex_unlock(&root->fs_info->fs_mutex);
590 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
591 size_t write_bytes = min(count,
592 (size_t)PAGE_CACHE_SIZE - offset);
593 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
596 memset(pages, 0, sizeof(pages));
597 ret = prepare_pages(root, file, pages, num_pages,
598 pos, first_index, last_index,
599 write_bytes, alloc_extent_start);
602 /* FIXME blocks != pagesize */
603 if (alloc_extent_start)
604 alloc_extent_start += num_pages;
605 ret = btrfs_copy_from_user(pos, num_pages,
606 write_bytes, pages, buf);
609 ret = dirty_and_release_pages(NULL, root, file, pages,
610 num_pages, pos, write_bytes);
612 btrfs_drop_pages(pages, num_pages);
615 count -= write_bytes;
617 num_written += write_bytes;
619 balance_dirty_pages_ratelimited(inode->i_mapping);
620 btrfs_btree_balance_dirty(root);
624 mutex_unlock(&inode->i_mutex);
627 page_cache_release(pinned[0]);
629 page_cache_release(pinned[1]);
631 current->backing_dev_info = NULL;
632 mark_inode_dirty(inode);
633 return num_written ? num_written : err;
637 * FIXME, do this by stuffing the csum we want in the info hanging off
638 * page->private. For now, verify file csums on read
640 static int btrfs_read_actor(read_descriptor_t *desc, struct page *page,
641 unsigned long offset, unsigned long size)
644 unsigned long left, count = desc->count;
645 struct inode *inode = page->mapping->host;
650 if (!PageChecked(page)) {
651 /* FIXME, do it per block */
652 struct btrfs_root *root = BTRFS_I(inode)->root;
654 struct buffer_head *bh;
656 if (page_has_buffers(page)) {
657 bh = page_buffers(page);
658 if (!buffer_mapped(bh)) {
659 SetPageChecked(page);
664 ret = btrfs_csum_verify_file_block(root,
665 page->mapping->host->i_ino,
666 page->index << PAGE_CACHE_SHIFT,
667 kmap(page), PAGE_CACHE_SIZE);
669 if (ret != -ENOENT) {
670 printk("failed to verify ino %lu page %lu ret %d\n",
671 page->mapping->host->i_ino,
673 memset(page_address(page), 1, PAGE_CACHE_SIZE);
674 flush_dcache_page(page);
677 SetPageChecked(page);
682 * Faults on the destination of a read are common, so do it before
685 if (!fault_in_pages_writeable(desc->arg.buf, size)) {
686 kaddr = kmap_atomic(page, KM_USER0);
687 left = __copy_to_user_inatomic(desc->arg.buf,
688 kaddr + offset, size);
689 kunmap_atomic(kaddr, KM_USER0);
694 /* Do it the slow way */
696 left = __copy_to_user(desc->arg.buf, kaddr + offset, size);
701 desc->error = -EFAULT;
704 desc->count = count - size;
705 desc->written += size;
706 desc->arg.buf += size;
711 * btrfs_file_aio_read - filesystem read routine, with a mod to csum verify
712 * @iocb: kernel I/O control block
713 * @iov: io vector request
714 * @nr_segs: number of segments in the iovec
715 * @pos: current file position
717 static ssize_t btrfs_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
718 unsigned long nr_segs, loff_t pos)
720 struct file *filp = iocb->ki_filp;
724 loff_t *ppos = &iocb->ki_pos;
727 for (seg = 0; seg < nr_segs; seg++) {
728 const struct iovec *iv = &iov[seg];
731 * If any segment has a negative length, or the cumulative
732 * length ever wraps negative then return -EINVAL.
734 count += iv->iov_len;
735 if (unlikely((ssize_t)(count|iv->iov_len) < 0))
737 if (access_ok(VERIFY_WRITE, iv->iov_base, iv->iov_len))
742 count -= iv->iov_len; /* This segment is no good */
747 for (seg = 0; seg < nr_segs; seg++) {
748 read_descriptor_t desc;
751 desc.arg.buf = iov[seg].iov_base;
752 desc.count = iov[seg].iov_len;
756 do_generic_file_read(filp, ppos, &desc,
758 retval += desc.written;
760 retval = retval ?: desc.error;
768 static int btrfs_sync_file(struct file *file,
769 struct dentry *dentry, int datasync)
771 struct inode *inode = dentry->d_inode;
772 struct btrfs_root *root = BTRFS_I(inode)->root;
774 struct btrfs_trans_handle *trans;
777 * FIXME, use inode generation number to check if we can skip the
780 mutex_lock(&root->fs_info->fs_mutex);
781 trans = btrfs_start_transaction(root, 1);
786 ret = btrfs_commit_transaction(trans, root);
787 mutex_unlock(&root->fs_info->fs_mutex);
789 return ret > 0 ? EIO : ret;
792 struct file_operations btrfs_file_operations = {
793 .llseek = generic_file_llseek,
794 .read = do_sync_read,
795 .aio_read = btrfs_file_aio_read,
796 .write = btrfs_file_write,
797 .mmap = generic_file_mmap,
798 .open = generic_file_open,
799 .ioctl = btrfs_ioctl,
800 .fsync = btrfs_sync_file,
802 .compat_ioctl = btrfs_compat_ioctl,