blob: ab07627084f13c4f84c39c39d802b258dbc181ab [file] [log] [blame]
Chris Masonc8b97812008-10-29 14:49:59 -04001/*
2 * Copyright (C) 2008 Oracle. All rights reserved.
3 *
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.
7 *
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.
12 *
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.
17 */
18
19#include <linux/kernel.h>
20#include <linux/bio.h>
21#include <linux/buffer_head.h>
22#include <linux/file.h>
23#include <linux/fs.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>
Chris Mason771ed682008-11-06 22:02:51 -050035#include <linux/pagevec.h>
Chris Mason4b4e25f2008-11-20 10:22:27 -050036#include "compat.h"
Chris Masonc8b97812008-10-29 14:49:59 -040037#include "ctree.h"
38#include "disk-io.h"
39#include "transaction.h"
40#include "btrfs_inode.h"
41#include "volumes.h"
42#include "ordered-data.h"
Chris Masonc8b97812008-10-29 14:49:59 -040043#include "compression.h"
44#include "extent_io.h"
45#include "extent_map.h"
46
47struct compressed_bio {
48 /* number of bios pending for this compressed extent */
49 atomic_t pending_bios;
50
51 /* the pages with the compressed data on them */
52 struct page **compressed_pages;
53
54 /* inode that owns this data */
55 struct inode *inode;
56
57 /* starting offset in the inode for our pages */
58 u64 start;
59
60 /* number of bytes in the inode we're working on */
61 unsigned long len;
62
63 /* number of bytes on disk */
64 unsigned long compressed_len;
65
66 /* number of compressed pages in the array */
67 unsigned long nr_pages;
68
69 /* IO errors */
70 int errors;
Chris Masond20f7042008-12-08 16:58:54 -050071 int mirror_num;
Chris Masonc8b97812008-10-29 14:49:59 -040072
73 /* for reads, this is the bio we are copying the data into */
74 struct bio *orig_bio;
Chris Masond20f7042008-12-08 16:58:54 -050075
76 /*
77 * the start of a variable length array of checksums only
78 * used by reads
79 */
80 u32 sums;
Chris Masonc8b97812008-10-29 14:49:59 -040081};
82
Chris Masond20f7042008-12-08 16:58:54 -050083static inline int compressed_bio_size(struct btrfs_root *root,
84 unsigned long disk_size)
85{
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) *
89 csum_size;
90}
91
Chris Masonc8b97812008-10-29 14:49:59 -040092static struct bio *compressed_bio_alloc(struct block_device *bdev,
93 u64 first_byte, gfp_t gfp_flags)
94{
95 struct bio *bio;
96 int nr_vecs;
97
98 nr_vecs = bio_get_nr_vecs(bdev);
99 bio = bio_alloc(gfp_flags, nr_vecs);
100
101 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
102 while (!bio && (nr_vecs /= 2))
103 bio = bio_alloc(gfp_flags, nr_vecs);
104 }
105
106 if (bio) {
107 bio->bi_size = 0;
108 bio->bi_bdev = bdev;
109 bio->bi_sector = first_byte >> 9;
110 }
111 return bio;
112}
113
Chris Masond20f7042008-12-08 16:58:54 -0500114static int check_compressed_csum(struct inode *inode,
115 struct compressed_bio *cb,
116 u64 disk_start)
117{
118 int ret;
119 struct btrfs_root *root = BTRFS_I(inode)->root;
120 struct page *page;
121 unsigned long i;
122 char *kaddr;
123 u32 csum;
124 u32 *cb_sum = &cb->sums;
125
Yan Zheng17d217f2008-12-12 10:03:38 -0500126 if (btrfs_test_flag(inode, NODATASUM))
Chris Masond20f7042008-12-08 16:58:54 -0500127 return 0;
128
129 for (i = 0; i < cb->nr_pages; i++) {
130 page = cb->compressed_pages[i];
131 csum = ~(u32)0;
132
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);
137
138 if (csum != *cb_sum) {
Chris Masond3977122009-01-05 21:25:51 -0500139 printk(KERN_INFO "btrfs csum failed ino %lu "
140 "extent %llu csum %u "
Chris Masond20f7042008-12-08 16:58:54 -0500141 "wanted %u mirror %d\n", inode->i_ino,
142 (unsigned long long)disk_start,
143 csum, *cb_sum, cb->mirror_num);
144 ret = -EIO;
145 goto fail;
146 }
147 cb_sum++;
148
149 }
150 ret = 0;
151fail:
152 return ret;
153}
154
Chris Masonc8b97812008-10-29 14:49:59 -0400155/* 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).
158 *
159 * This allows the checksumming and other IO error handling routines
160 * to work normally
161 *
162 * The compressed pages are freed here, and it must be run
163 * in process context
164 */
165static void end_compressed_bio_read(struct bio *bio, int err)
166{
167 struct extent_io_tree *tree;
168 struct compressed_bio *cb = bio->bi_private;
169 struct inode *inode;
170 struct page *page;
171 unsigned long index;
172 int ret;
173
174 if (err)
175 cb->errors = 1;
176
177 /* if there are more bios still pending for this compressed
178 * extent, just exit
179 */
180 if (!atomic_dec_and_test(&cb->pending_bios))
181 goto out;
182
Chris Masond20f7042008-12-08 16:58:54 -0500183 inode = cb->inode;
184 ret = check_compressed_csum(inode, cb, (u64)bio->bi_sector << 9);
185 if (ret)
186 goto csum_failed;
187
Chris Masonc8b97812008-10-29 14:49:59 -0400188 /* ok, we're the last bio for this extent, lets start
189 * the decompression.
190 */
Chris Masonc8b97812008-10-29 14:49:59 -0400191 tree = &BTRFS_I(inode)->io_tree;
192 ret = btrfs_zlib_decompress_biovec(cb->compressed_pages,
193 cb->start,
194 cb->orig_bio->bi_io_vec,
195 cb->orig_bio->bi_vcnt,
196 cb->compressed_len);
Chris Masond20f7042008-12-08 16:58:54 -0500197csum_failed:
Chris Masonc8b97812008-10-29 14:49:59 -0400198 if (ret)
199 cb->errors = 1;
200
201 /* release the compressed pages */
202 index = 0;
203 for (index = 0; index < cb->nr_pages; index++) {
204 page = cb->compressed_pages[index];
205 page->mapping = NULL;
206 page_cache_release(page);
207 }
208
209 /* do io completion on the original bio */
Chris Mason771ed682008-11-06 22:02:51 -0500210 if (cb->errors) {
Chris Masonc8b97812008-10-29 14:49:59 -0400211 bio_io_error(cb->orig_bio);
Chris Masond20f7042008-12-08 16:58:54 -0500212 } else {
213 int bio_index = 0;
214 struct bio_vec *bvec = cb->orig_bio->bi_io_vec;
215
216 /*
217 * we have verified the checksum already, set page
218 * checked so the end_io handlers know about it
219 */
Chris Masond3977122009-01-05 21:25:51 -0500220 while (bio_index < cb->orig_bio->bi_vcnt) {
Chris Masond20f7042008-12-08 16:58:54 -0500221 SetPageChecked(bvec->bv_page);
222 bvec++;
223 bio_index++;
224 }
Chris Masonc8b97812008-10-29 14:49:59 -0400225 bio_endio(cb->orig_bio, 0);
Chris Masond20f7042008-12-08 16:58:54 -0500226 }
Chris Masonc8b97812008-10-29 14:49:59 -0400227
228 /* finally free the cb struct */
229 kfree(cb->compressed_pages);
230 kfree(cb);
231out:
232 bio_put(bio);
233}
234
235/*
236 * Clear the writeback bits on all of the file
237 * pages for a compressed write
238 */
239static noinline int end_compressed_writeback(struct inode *inode, u64 start,
240 unsigned long ram_size)
241{
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;
246 int i;
247 int ret;
248
Chris Masond3977122009-01-05 21:25:51 -0500249 while (nr_pages > 0) {
Chris Masonc8b97812008-10-29 14:49:59 -0400250 ret = find_get_pages_contig(inode->i_mapping, index,
Chris Mason5b050f02008-11-11 09:34:41 -0500251 min_t(unsigned long,
252 nr_pages, ARRAY_SIZE(pages)), pages);
Chris Masonc8b97812008-10-29 14:49:59 -0400253 if (ret == 0) {
254 nr_pages -= 1;
255 index += 1;
256 continue;
257 }
258 for (i = 0; i < ret; i++) {
259 end_page_writeback(pages[i]);
260 page_cache_release(pages[i]);
261 }
262 nr_pages -= ret;
263 index += ret;
264 }
265 /* the inode may be gone now */
266 return 0;
267}
268
269/*
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
272 * pages.
273 *
274 * This also calls the writeback end hooks for the file pages so that
275 * metadata and checksums can be updated in the file.
276 */
277static void end_compressed_bio_write(struct bio *bio, int err)
278{
279 struct extent_io_tree *tree;
280 struct compressed_bio *cb = bio->bi_private;
281 struct inode *inode;
282 struct page *page;
283 unsigned long index;
284
285 if (err)
286 cb->errors = 1;
287
288 /* if there are more bios still pending for this compressed
289 * extent, just exit
290 */
291 if (!atomic_dec_and_test(&cb->pending_bios))
292 goto out;
293
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
296 */
297 inode = cb->inode;
298 tree = &BTRFS_I(inode)->io_tree;
Chris Mason70b99e62008-10-31 12:46:39 -0400299 cb->compressed_pages[0]->mapping = cb->inode->i_mapping;
Chris Masonc8b97812008-10-29 14:49:59 -0400300 tree->ops->writepage_end_io_hook(cb->compressed_pages[0],
301 cb->start,
302 cb->start + cb->len - 1,
303 NULL, 1);
Chris Mason70b99e62008-10-31 12:46:39 -0400304 cb->compressed_pages[0]->mapping = NULL;
Chris Masonc8b97812008-10-29 14:49:59 -0400305
306 end_compressed_writeback(inode, cb->start, cb->len);
307 /* note, our inode could be gone now */
308
309 /*
310 * release the compressed pages, these came from alloc_page and
311 * are not attached to the inode at all
312 */
313 index = 0;
314 for (index = 0; index < cb->nr_pages; index++) {
315 page = cb->compressed_pages[index];
316 page->mapping = NULL;
317 page_cache_release(page);
318 }
319
320 /* finally free the cb struct */
321 kfree(cb->compressed_pages);
322 kfree(cb);
323out:
324 bio_put(bio);
325}
326
327/*
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.
332 *
333 * This also checksums the file bytes and gets things ready for
334 * the end io hooks.
335 */
336int 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)
341{
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;
347 int page_index = 0;
348 struct page *page;
349 u64 first_byte = disk_start;
350 struct block_device *bdev;
351 int ret;
352
353 WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1));
Chris Masond20f7042008-12-08 16:58:54 -0500354 cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
Chris Masonc8b97812008-10-29 14:49:59 -0400355 atomic_set(&cb->pending_bios, 0);
356 cb->errors = 0;
357 cb->inode = inode;
358 cb->start = start;
359 cb->len = len;
Chris Masond20f7042008-12-08 16:58:54 -0500360 cb->mirror_num = 0;
Chris Masonc8b97812008-10-29 14:49:59 -0400361 cb->compressed_pages = compressed_pages;
362 cb->compressed_len = compressed_len;
363 cb->orig_bio = NULL;
364 cb->nr_pages = nr_pages;
365
366 bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
367
Chris Masonc8b97812008-10-29 14:49:59 -0400368 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);
372
373 /* create and submit bios for the compressed pages */
374 bytes_left = compressed_len;
Chris Masoncfbc2462008-10-30 13:22:14 -0400375 for (page_index = 0; page_index < cb->nr_pages; page_index++) {
Chris Masonc8b97812008-10-29 14:49:59 -0400376 page = compressed_pages[page_index];
377 page->mapping = inode->i_mapping;
378 if (bio->bi_size)
379 ret = io_tree->ops->merge_bio_hook(page, 0,
380 PAGE_CACHE_SIZE,
381 bio, 0);
382 else
383 ret = 0;
384
Chris Mason70b99e62008-10-31 12:46:39 -0400385 page->mapping = NULL;
Chris Masonc8b97812008-10-29 14:49:59 -0400386 if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) <
387 PAGE_CACHE_SIZE) {
388 bio_get(bio);
389
Chris Masonaf09abf2008-11-07 12:35:44 -0500390 /*
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
395 */
396 atomic_inc(&cb->pending_bios);
Chris Masonc8b97812008-10-29 14:49:59 -0400397 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
398 BUG_ON(ret);
399
Chris Masond20f7042008-12-08 16:58:54 -0500400 ret = btrfs_csum_one_bio(root, inode, bio, start, 1);
401 BUG_ON(ret);
402
Chris Masonc8b97812008-10-29 14:49:59 -0400403 ret = btrfs_map_bio(root, WRITE, bio, 0, 1);
404 BUG_ON(ret);
405
406 bio_put(bio);
407
408 bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS);
Chris Masonc8b97812008-10-29 14:49:59 -0400409 bio->bi_private = cb;
410 bio->bi_end_io = end_compressed_bio_write;
411 bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
412 }
Chris Masoncfbc2462008-10-30 13:22:14 -0400413 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);
416 }
Chris Masonc8b97812008-10-29 14:49:59 -0400417 bytes_left -= PAGE_CACHE_SIZE;
418 first_byte += PAGE_CACHE_SIZE;
Chris Mason771ed682008-11-06 22:02:51 -0500419 cond_resched();
Chris Masonc8b97812008-10-29 14:49:59 -0400420 }
421 bio_get(bio);
422
423 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
424 BUG_ON(ret);
425
Chris Masond20f7042008-12-08 16:58:54 -0500426 ret = btrfs_csum_one_bio(root, inode, bio, start, 1);
427 BUG_ON(ret);
428
Chris Masonc8b97812008-10-29 14:49:59 -0400429 ret = btrfs_map_bio(root, WRITE, bio, 0, 1);
430 BUG_ON(ret);
431
432 bio_put(bio);
433 return 0;
434}
435
Chris Mason771ed682008-11-06 22:02:51 -0500436static noinline int add_ra_bio_pages(struct inode *inode,
437 u64 compressed_end,
438 struct compressed_bio *cb)
439{
440 unsigned long end_index;
441 unsigned long page_index;
442 u64 last_offset;
443 u64 isize = i_size_read(inode);
444 int ret;
445 struct page *page;
446 unsigned long nr_pages = 0;
447 struct extent_map *em;
448 struct address_space *mapping = inode->i_mapping;
449 struct pagevec pvec;
450 struct extent_map_tree *em_tree;
451 struct extent_io_tree *tree;
452 u64 end;
453 int misses = 0;
454
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;
459
460 if (isize == 0)
461 return 0;
462
463 end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
464
465 pagevec_init(&pvec, 0);
Chris Masond3977122009-01-05 21:25:51 -0500466 while (last_offset < compressed_end) {
Chris Mason771ed682008-11-06 22:02:51 -0500467 page_index = last_offset >> PAGE_CACHE_SHIFT;
468
469 if (page_index > end_index)
470 break;
471
472 rcu_read_lock();
473 page = radix_tree_lookup(&mapping->page_tree, page_index);
474 rcu_read_unlock();
475 if (page) {
476 misses++;
477 if (misses > 4)
478 break;
479 goto next;
480 }
481
482 page = alloc_page(mapping_gfp_mask(mapping) | GFP_NOFS);
483 if (!page)
484 break;
485
486 page->index = page_index;
487 /*
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
490 */
491 if (add_to_page_cache(page, mapping,
492 page->index, GFP_NOFS)) {
493 page_cache_release(page);
494 goto next;
495 }
496
497 /* open coding of lru_cache_add, also not exported */
498 page_cache_get(page);
499 if (!pagevec_add(&pvec, page))
Chris Mason15916de2008-11-19 21:17:22 -0500500 __pagevec_lru_add_file(&pvec);
Chris Mason771ed682008-11-06 22:02:51 -0500501
502 end = last_offset + PAGE_CACHE_SIZE - 1;
503 /*
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.
507 */
508 set_page_extent_mapped(page);
509 lock_extent(tree, last_offset, end, GFP_NOFS);
510 spin_lock(&em_tree->lock);
511 em = lookup_extent_mapping(em_tree, last_offset,
512 PAGE_CACHE_SIZE);
513 spin_unlock(&em_tree->lock);
514
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) {
518 free_extent_map(em);
519 unlock_extent(tree, last_offset, end, GFP_NOFS);
520 unlock_page(page);
521 page_cache_release(page);
522 break;
523 }
524 free_extent_map(em);
525
526 if (page->index == end_index) {
527 char *userpage;
528 size_t zero_offset = isize & (PAGE_CACHE_SIZE - 1);
529
530 if (zero_offset) {
531 int zeros;
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);
537 }
538 }
539
540 ret = bio_add_page(cb->orig_bio, page,
541 PAGE_CACHE_SIZE, 0);
542
543 if (ret == PAGE_CACHE_SIZE) {
544 nr_pages++;
545 page_cache_release(page);
546 } else {
547 unlock_extent(tree, last_offset, end, GFP_NOFS);
548 unlock_page(page);
549 page_cache_release(page);
550 break;
551 }
552next:
553 last_offset += PAGE_CACHE_SIZE;
554 }
555 if (pagevec_count(&pvec))
Chris Mason15916de2008-11-19 21:17:22 -0500556 __pagevec_lru_add_file(&pvec);
Chris Mason771ed682008-11-06 22:02:51 -0500557 return 0;
558}
559
Chris Masonc8b97812008-10-29 14:49:59 -0400560/*
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.
564 *
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
568 *
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
571 */
572int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
573 int mirror_num, unsigned long bio_flags)
574{
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;
583 struct page *page;
584 struct block_device *bdev;
585 struct bio *comp_bio;
586 u64 cur_disk_byte = (u64)bio->bi_sector << 9;
Chris Masone04ca622008-11-10 11:44:58 -0500587 u64 em_len;
588 u64 em_start;
Chris Masonc8b97812008-10-29 14:49:59 -0400589 struct extent_map *em;
590 int ret;
Chris Masond20f7042008-12-08 16:58:54 -0500591 u32 *sums;
Chris Masonc8b97812008-10-29 14:49:59 -0400592
593 tree = &BTRFS_I(inode)->io_tree;
594 em_tree = &BTRFS_I(inode)->extent_tree;
595
596 /* we need the actual starting offset of this extent in the file */
597 spin_lock(&em_tree->lock);
598 em = lookup_extent_mapping(em_tree,
599 page_offset(bio->bi_io_vec->bv_page),
600 PAGE_CACHE_SIZE);
601 spin_unlock(&em_tree->lock);
602
Chris Masond20f7042008-12-08 16:58:54 -0500603 compressed_len = em->block_len;
604 cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
Chris Masonc8b97812008-10-29 14:49:59 -0400605 atomic_set(&cb->pending_bios, 0);
606 cb->errors = 0;
607 cb->inode = inode;
Chris Masond20f7042008-12-08 16:58:54 -0500608 cb->mirror_num = mirror_num;
609 sums = &cb->sums;
Chris Masonc8b97812008-10-29 14:49:59 -0400610
Yan Zhengff5b7ee2008-11-10 07:34:43 -0500611 cb->start = em->orig_start;
Chris Masone04ca622008-11-10 11:44:58 -0500612 em_len = em->len;
613 em_start = em->start;
Chris Masond20f7042008-12-08 16:58:54 -0500614
Chris Masonc8b97812008-10-29 14:49:59 -0400615 free_extent_map(em);
Chris Masone04ca622008-11-10 11:44:58 -0500616 em = NULL;
Chris Masonc8b97812008-10-29 14:49:59 -0400617
618 cb->len = uncompressed_len;
619 cb->compressed_len = compressed_len;
620 cb->orig_bio = bio;
621
622 nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) /
623 PAGE_CACHE_SIZE;
624 cb->compressed_pages = kmalloc(sizeof(struct page *) * nr_pages,
625 GFP_NOFS);
626 bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
627
628 for (page_index = 0; page_index < nr_pages; page_index++) {
629 cb->compressed_pages[page_index] = alloc_page(GFP_NOFS |
630 __GFP_HIGHMEM);
631 }
632 cb->nr_pages = nr_pages;
633
Chris Masone04ca622008-11-10 11:44:58 -0500634 add_ra_bio_pages(inode, em_start + em_len, cb);
Chris Mason771ed682008-11-06 22:02:51 -0500635
Chris Mason771ed682008-11-06 22:02:51 -0500636 /* include any pages we added in add_ra-bio_pages */
637 uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE;
638 cb->len = uncompressed_len;
639
Chris Masonc8b97812008-10-29 14:49:59 -0400640 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);
644
645 for (page_index = 0; page_index < nr_pages; page_index++) {
646 page = cb->compressed_pages[page_index];
647 page->mapping = inode->i_mapping;
Chris Masond20f7042008-12-08 16:58:54 -0500648 page->index = em_start >> PAGE_CACHE_SHIFT;
649
Chris Masonc8b97812008-10-29 14:49:59 -0400650 if (comp_bio->bi_size)
651 ret = tree->ops->merge_bio_hook(page, 0,
652 PAGE_CACHE_SIZE,
653 comp_bio, 0);
654 else
655 ret = 0;
656
Chris Mason70b99e62008-10-31 12:46:39 -0400657 page->mapping = NULL;
Chris Masonc8b97812008-10-29 14:49:59 -0400658 if (ret || bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0) <
659 PAGE_CACHE_SIZE) {
660 bio_get(comp_bio);
661
662 ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0);
663 BUG_ON(ret);
664
Chris Masonaf09abf2008-11-07 12:35:44 -0500665 /*
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
670 */
671 atomic_inc(&cb->pending_bios);
672
Yan Zheng17d217f2008-12-12 10:03:38 -0500673 if (!btrfs_test_flag(inode, NODATASUM)) {
Chris Masond20f7042008-12-08 16:58:54 -0500674 btrfs_lookup_bio_sums(root, inode, comp_bio,
675 sums);
676 }
677 sums += (comp_bio->bi_size + root->sectorsize - 1) /
678 root->sectorsize;
679
680 ret = btrfs_map_bio(root, READ, comp_bio,
681 mirror_num, 0);
Chris Masonc8b97812008-10-29 14:49:59 -0400682 BUG_ON(ret);
683
684 bio_put(comp_bio);
685
686 comp_bio = compressed_bio_alloc(bdev, cur_disk_byte,
687 GFP_NOFS);
Chris Mason771ed682008-11-06 22:02:51 -0500688 comp_bio->bi_private = cb;
689 comp_bio->bi_end_io = end_compressed_bio_read;
690
691 bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0);
Chris Masonc8b97812008-10-29 14:49:59 -0400692 }
693 cur_disk_byte += PAGE_CACHE_SIZE;
694 }
695 bio_get(comp_bio);
696
697 ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0);
698 BUG_ON(ret);
699
Chris Masond3977122009-01-05 21:25:51 -0500700 if (!btrfs_test_flag(inode, NODATASUM))
Chris Masond20f7042008-12-08 16:58:54 -0500701 btrfs_lookup_bio_sums(root, inode, comp_bio, sums);
Chris Masond20f7042008-12-08 16:58:54 -0500702
703 ret = btrfs_map_bio(root, READ, comp_bio, mirror_num, 0);
Chris Masonc8b97812008-10-29 14:49:59 -0400704 BUG_ON(ret);
705
706 bio_put(comp_bio);
707 return 0;
708}