2 * Copyright (C) 2008 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/kernel.h>
20 #include <linux/bio.h>
21 #include <linux/buffer_head.h>
22 #include <linux/file.h>
24 #include <linux/pagemap.h>
25 #include <linux/highmem.h>
26 #include <linux/time.h>
27 #include <linux/init.h>
28 #include <linux/string.h>
29 #include <linux/smp_lock.h>
30 #include <linux/backing-dev.h>
31 #include <linux/mpage.h>
32 #include <linux/swap.h>
33 #include <linux/writeback.h>
34 #include <linux/bit_spinlock.h>
35 #include <linux/pagevec.h>
39 #include "transaction.h"
40 #include "btrfs_inode.h"
42 #include "ordered-data.h"
43 #include "compression.h"
44 #include "extent_io.h"
45 #include "extent_map.h"
47 struct compressed_bio {
48 /* number of bios pending for this compressed extent */
49 atomic_t pending_bios;
51 /* the pages with the compressed data on them */
52 struct page **compressed_pages;
54 /* inode that owns this data */
57 /* starting offset in the inode for our pages */
60 /* number of bytes in the inode we're working on */
63 /* number of bytes on disk */
64 unsigned long compressed_len;
66 /* number of compressed pages in the array */
67 unsigned long nr_pages;
73 /* for reads, this is the bio we are copying the data into */
77 * the start of a variable length array of checksums only
83 static inline int compressed_bio_size(struct btrfs_root *root,
84 unsigned long disk_size)
86 u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy);
87 return sizeof(struct compressed_bio) +
88 ((disk_size + root->sectorsize - 1) / root->sectorsize) *
92 static struct bio *compressed_bio_alloc(struct block_device *bdev,
93 u64 first_byte, gfp_t gfp_flags)
98 nr_vecs = bio_get_nr_vecs(bdev);
99 bio = bio_alloc(gfp_flags, nr_vecs);
101 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
102 while (!bio && (nr_vecs /= 2))
103 bio = bio_alloc(gfp_flags, nr_vecs);
109 bio->bi_sector = first_byte >> 9;
114 static int check_compressed_csum(struct inode *inode,
115 struct compressed_bio *cb,
119 struct btrfs_root *root = BTRFS_I(inode)->root;
124 u32 *cb_sum = &cb->sums;
126 if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
129 for (i = 0; i < cb->nr_pages; i++) {
130 page = cb->compressed_pages[i];
133 kaddr = kmap_atomic(page, KM_USER0);
134 csum = btrfs_csum_data(root, kaddr, csum, PAGE_CACHE_SIZE);
135 btrfs_csum_final(csum, (char *)&csum);
136 kunmap_atomic(kaddr, KM_USER0);
138 if (csum != *cb_sum) {
139 printk(KERN_INFO "btrfs csum failed ino %lu "
140 "extent %llu csum %u "
141 "wanted %u mirror %d\n", inode->i_ino,
142 (unsigned long long)disk_start,
143 csum, *cb_sum, cb->mirror_num);
155 /* when we finish reading compressed pages from the disk, we
156 * decompress them and then run the bio end_io routines on the
157 * decompressed pages (in the inode address space).
159 * This allows the checksumming and other IO error handling routines
162 * The compressed pages are freed here, and it must be run
165 static void end_compressed_bio_read(struct bio *bio, int err)
167 struct extent_io_tree *tree;
168 struct compressed_bio *cb = bio->bi_private;
177 /* if there are more bios still pending for this compressed
180 if (!atomic_dec_and_test(&cb->pending_bios))
184 ret = check_compressed_csum(inode, cb, (u64)bio->bi_sector << 9);
188 /* ok, we're the last bio for this extent, lets start
191 tree = &BTRFS_I(inode)->io_tree;
192 ret = btrfs_zlib_decompress_biovec(cb->compressed_pages,
194 cb->orig_bio->bi_io_vec,
195 cb->orig_bio->bi_vcnt,
201 /* release the compressed pages */
203 for (index = 0; index < cb->nr_pages; index++) {
204 page = cb->compressed_pages[index];
205 page->mapping = NULL;
206 page_cache_release(page);
209 /* do io completion on the original bio */
211 bio_io_error(cb->orig_bio);
214 struct bio_vec *bvec = cb->orig_bio->bi_io_vec;
217 * we have verified the checksum already, set page
218 * checked so the end_io handlers know about it
220 while (bio_index < cb->orig_bio->bi_vcnt) {
221 SetPageChecked(bvec->bv_page);
225 bio_endio(cb->orig_bio, 0);
228 /* finally free the cb struct */
229 kfree(cb->compressed_pages);
236 * Clear the writeback bits on all of the file
237 * pages for a compressed write
239 static noinline int end_compressed_writeback(struct inode *inode, u64 start,
240 unsigned long ram_size)
242 unsigned long index = start >> PAGE_CACHE_SHIFT;
243 unsigned long end_index = (start + ram_size - 1) >> PAGE_CACHE_SHIFT;
244 struct page *pages[16];
245 unsigned long nr_pages = end_index - index + 1;
249 while (nr_pages > 0) {
250 ret = find_get_pages_contig(inode->i_mapping, index,
252 nr_pages, ARRAY_SIZE(pages)), pages);
258 for (i = 0; i < ret; i++) {
259 end_page_writeback(pages[i]);
260 page_cache_release(pages[i]);
265 /* the inode may be gone now */
270 * do the cleanup once all the compressed pages hit the disk.
271 * This will clear writeback on the file pages and free the compressed
274 * This also calls the writeback end hooks for the file pages so that
275 * metadata and checksums can be updated in the file.
277 static void end_compressed_bio_write(struct bio *bio, int err)
279 struct extent_io_tree *tree;
280 struct compressed_bio *cb = bio->bi_private;
288 /* if there are more bios still pending for this compressed
291 if (!atomic_dec_and_test(&cb->pending_bios))
294 /* ok, we're the last bio for this extent, step one is to
295 * call back into the FS and do all the end_io operations
298 tree = &BTRFS_I(inode)->io_tree;
299 cb->compressed_pages[0]->mapping = cb->inode->i_mapping;
300 tree->ops->writepage_end_io_hook(cb->compressed_pages[0],
302 cb->start + cb->len - 1,
304 cb->compressed_pages[0]->mapping = NULL;
306 end_compressed_writeback(inode, cb->start, cb->len);
307 /* note, our inode could be gone now */
310 * release the compressed pages, these came from alloc_page and
311 * are not attached to the inode at all
314 for (index = 0; index < cb->nr_pages; index++) {
315 page = cb->compressed_pages[index];
316 page->mapping = NULL;
317 page_cache_release(page);
320 /* finally free the cb struct */
321 kfree(cb->compressed_pages);
328 * worker function to build and submit bios for previously compressed pages.
329 * The corresponding pages in the inode should be marked for writeback
330 * and the compressed pages should have a reference on them for dropping
331 * when the IO is complete.
333 * This also checksums the file bytes and gets things ready for
336 int btrfs_submit_compressed_write(struct inode *inode, u64 start,
337 unsigned long len, u64 disk_start,
338 unsigned long compressed_len,
339 struct page **compressed_pages,
340 unsigned long nr_pages)
342 struct bio *bio = NULL;
343 struct btrfs_root *root = BTRFS_I(inode)->root;
344 struct compressed_bio *cb;
345 unsigned long bytes_left;
346 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
349 u64 first_byte = disk_start;
350 struct block_device *bdev;
353 WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1));
354 cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
355 atomic_set(&cb->pending_bios, 0);
361 cb->compressed_pages = compressed_pages;
362 cb->compressed_len = compressed_len;
364 cb->nr_pages = nr_pages;
366 bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
368 bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS);
369 bio->bi_private = cb;
370 bio->bi_end_io = end_compressed_bio_write;
371 atomic_inc(&cb->pending_bios);
373 /* create and submit bios for the compressed pages */
374 bytes_left = compressed_len;
375 for (page_index = 0; page_index < cb->nr_pages; page_index++) {
376 page = compressed_pages[page_index];
377 page->mapping = inode->i_mapping;
379 ret = io_tree->ops->merge_bio_hook(page, 0,
385 page->mapping = NULL;
386 if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) <
391 * inc the count before we submit the bio so
392 * we know the end IO handler won't happen before
393 * we inc the count. Otherwise, the cb might get
394 * freed before we're done setting it up
396 atomic_inc(&cb->pending_bios);
397 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
400 ret = btrfs_csum_one_bio(root, inode, bio, start, 1);
403 ret = btrfs_map_bio(root, WRITE, bio, 0, 1);
408 bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS);
409 bio->bi_private = cb;
410 bio->bi_end_io = end_compressed_bio_write;
411 bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
413 if (bytes_left < PAGE_CACHE_SIZE) {
414 printk("bytes left %lu compress len %lu nr %lu\n",
415 bytes_left, cb->compressed_len, cb->nr_pages);
417 bytes_left -= PAGE_CACHE_SIZE;
418 first_byte += PAGE_CACHE_SIZE;
423 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
426 ret = btrfs_csum_one_bio(root, inode, bio, start, 1);
429 ret = btrfs_map_bio(root, WRITE, bio, 0, 1);
436 static noinline int add_ra_bio_pages(struct inode *inode,
438 struct compressed_bio *cb)
440 unsigned long end_index;
441 unsigned long page_index;
443 u64 isize = i_size_read(inode);
446 unsigned long nr_pages = 0;
447 struct extent_map *em;
448 struct address_space *mapping = inode->i_mapping;
450 struct extent_map_tree *em_tree;
451 struct extent_io_tree *tree;
455 page = cb->orig_bio->bi_io_vec[cb->orig_bio->bi_vcnt - 1].bv_page;
456 last_offset = (page_offset(page) + PAGE_CACHE_SIZE);
457 em_tree = &BTRFS_I(inode)->extent_tree;
458 tree = &BTRFS_I(inode)->io_tree;
463 end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
465 pagevec_init(&pvec, 0);
466 while (last_offset < compressed_end) {
467 page_index = last_offset >> PAGE_CACHE_SHIFT;
469 if (page_index > end_index)
473 page = radix_tree_lookup(&mapping->page_tree, page_index);
482 page = alloc_page(mapping_gfp_mask(mapping) | GFP_NOFS);
486 page->index = page_index;
488 * what we want to do here is call add_to_page_cache_lru,
489 * but that isn't exported, so we reproduce it here
491 if (add_to_page_cache(page, mapping,
492 page->index, GFP_NOFS)) {
493 page_cache_release(page);
497 /* open coding of lru_cache_add, also not exported */
498 page_cache_get(page);
499 if (!pagevec_add(&pvec, page))
500 __pagevec_lru_add_file(&pvec);
502 end = last_offset + PAGE_CACHE_SIZE - 1;
504 * at this point, we have a locked page in the page cache
505 * for these bytes in the file. But, we have to make
506 * sure they map to this compressed extent on disk.
508 set_page_extent_mapped(page);
509 lock_extent(tree, last_offset, end, GFP_NOFS);
510 read_lock(&em_tree->lock);
511 em = lookup_extent_mapping(em_tree, last_offset,
513 read_unlock(&em_tree->lock);
515 if (!em || last_offset < em->start ||
516 (last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) ||
517 (em->block_start >> 9) != cb->orig_bio->bi_sector) {
519 unlock_extent(tree, last_offset, end, GFP_NOFS);
521 page_cache_release(page);
526 if (page->index == end_index) {
528 size_t zero_offset = isize & (PAGE_CACHE_SIZE - 1);
532 zeros = PAGE_CACHE_SIZE - zero_offset;
533 userpage = kmap_atomic(page, KM_USER0);
534 memset(userpage + zero_offset, 0, zeros);
535 flush_dcache_page(page);
536 kunmap_atomic(userpage, KM_USER0);
540 ret = bio_add_page(cb->orig_bio, page,
543 if (ret == PAGE_CACHE_SIZE) {
545 page_cache_release(page);
547 unlock_extent(tree, last_offset, end, GFP_NOFS);
549 page_cache_release(page);
553 last_offset += PAGE_CACHE_SIZE;
555 if (pagevec_count(&pvec))
556 __pagevec_lru_add_file(&pvec);
561 * for a compressed read, the bio we get passed has all the inode pages
562 * in it. We don't actually do IO on those pages but allocate new ones
563 * to hold the compressed pages on disk.
565 * bio->bi_sector points to the compressed extent on disk
566 * bio->bi_io_vec points to all of the inode pages
567 * bio->bi_vcnt is a count of pages
569 * After the compressed pages are read, we copy the bytes into the
570 * bio we were passed and then call the bio end_io calls
572 int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
573 int mirror_num, unsigned long bio_flags)
575 struct extent_io_tree *tree;
576 struct extent_map_tree *em_tree;
577 struct compressed_bio *cb;
578 struct btrfs_root *root = BTRFS_I(inode)->root;
579 unsigned long uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE;
580 unsigned long compressed_len;
581 unsigned long nr_pages;
582 unsigned long page_index;
584 struct block_device *bdev;
585 struct bio *comp_bio;
586 u64 cur_disk_byte = (u64)bio->bi_sector << 9;
589 struct extent_map *em;
593 tree = &BTRFS_I(inode)->io_tree;
594 em_tree = &BTRFS_I(inode)->extent_tree;
596 /* we need the actual starting offset of this extent in the file */
597 read_lock(&em_tree->lock);
598 em = lookup_extent_mapping(em_tree,
599 page_offset(bio->bi_io_vec->bv_page),
601 read_unlock(&em_tree->lock);
603 compressed_len = em->block_len;
604 cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
605 atomic_set(&cb->pending_bios, 0);
608 cb->mirror_num = mirror_num;
611 cb->start = em->orig_start;
613 em_start = em->start;
618 cb->len = uncompressed_len;
619 cb->compressed_len = compressed_len;
622 nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) /
624 cb->compressed_pages = kmalloc(sizeof(struct page *) * nr_pages,
626 bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
628 for (page_index = 0; page_index < nr_pages; page_index++) {
629 cb->compressed_pages[page_index] = alloc_page(GFP_NOFS |
632 cb->nr_pages = nr_pages;
634 add_ra_bio_pages(inode, em_start + em_len, cb);
636 /* include any pages we added in add_ra-bio_pages */
637 uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE;
638 cb->len = uncompressed_len;
640 comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS);
641 comp_bio->bi_private = cb;
642 comp_bio->bi_end_io = end_compressed_bio_read;
643 atomic_inc(&cb->pending_bios);
645 for (page_index = 0; page_index < nr_pages; page_index++) {
646 page = cb->compressed_pages[page_index];
647 page->mapping = inode->i_mapping;
648 page->index = em_start >> PAGE_CACHE_SHIFT;
650 if (comp_bio->bi_size)
651 ret = tree->ops->merge_bio_hook(page, 0,
657 page->mapping = NULL;
658 if (ret || bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0) <
662 ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0);
666 * inc the count before we submit the bio so
667 * we know the end IO handler won't happen before
668 * we inc the count. Otherwise, the cb might get
669 * freed before we're done setting it up
671 atomic_inc(&cb->pending_bios);
673 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
674 btrfs_lookup_bio_sums(root, inode, comp_bio,
677 sums += (comp_bio->bi_size + root->sectorsize - 1) /
680 ret = btrfs_map_bio(root, READ, comp_bio,
686 comp_bio = compressed_bio_alloc(bdev, cur_disk_byte,
688 comp_bio->bi_private = cb;
689 comp_bio->bi_end_io = end_compressed_bio_read;
691 bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0);
693 cur_disk_byte += PAGE_CACHE_SIZE;
697 ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0);
700 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM))
701 btrfs_lookup_bio_sums(root, inode, comp_bio, sums);
703 ret = btrfs_map_bio(root, READ, comp_bio, mirror_num, 0);