blob: 7845d1f7d1d927f79ac45c09af730963a426b8e5 [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>
Chris Masonc8b97812008-10-29 14:49:59 -040029#include <linux/backing-dev.h>
30#include <linux/mpage.h>
31#include <linux/swap.h>
32#include <linux/writeback.h>
33#include <linux/bit_spinlock.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090034#include <linux/slab.h>
Chris Mason4b4e25f2008-11-20 10:22:27 -050035#include "compat.h"
Chris Masonc8b97812008-10-29 14:49:59 -040036#include "ctree.h"
37#include "disk-io.h"
38#include "transaction.h"
39#include "btrfs_inode.h"
40#include "volumes.h"
41#include "ordered-data.h"
Chris Masonc8b97812008-10-29 14:49:59 -040042#include "compression.h"
43#include "extent_io.h"
44#include "extent_map.h"
45
46struct compressed_bio {
47 /* number of bios pending for this compressed extent */
48 atomic_t pending_bios;
49
50 /* the pages with the compressed data on them */
51 struct page **compressed_pages;
52
53 /* inode that owns this data */
54 struct inode *inode;
55
56 /* starting offset in the inode for our pages */
57 u64 start;
58
59 /* number of bytes in the inode we're working on */
60 unsigned long len;
61
62 /* number of bytes on disk */
63 unsigned long compressed_len;
64
65 /* number of compressed pages in the array */
66 unsigned long nr_pages;
67
68 /* IO errors */
69 int errors;
Chris Masond20f7042008-12-08 16:58:54 -050070 int mirror_num;
Chris Masonc8b97812008-10-29 14:49:59 -040071
72 /* for reads, this is the bio we are copying the data into */
73 struct bio *orig_bio;
Chris Masond20f7042008-12-08 16:58:54 -050074
75 /*
76 * the start of a variable length array of checksums only
77 * used by reads
78 */
79 u32 sums;
Chris Masonc8b97812008-10-29 14:49:59 -040080};
81
Chris Masond20f7042008-12-08 16:58:54 -050082static inline int compressed_bio_size(struct btrfs_root *root,
83 unsigned long disk_size)
84{
85 u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy);
86 return sizeof(struct compressed_bio) +
87 ((disk_size + root->sectorsize - 1) / root->sectorsize) *
88 csum_size;
89}
90
Chris Masonc8b97812008-10-29 14:49:59 -040091static struct bio *compressed_bio_alloc(struct block_device *bdev,
92 u64 first_byte, gfp_t gfp_flags)
93{
94 struct bio *bio;
95 int nr_vecs;
96
97 nr_vecs = bio_get_nr_vecs(bdev);
98 bio = bio_alloc(gfp_flags, nr_vecs);
99
100 if (bio == NULL && (current->flags & PF_MEMALLOC)) {
101 while (!bio && (nr_vecs /= 2))
102 bio = bio_alloc(gfp_flags, nr_vecs);
103 }
104
105 if (bio) {
106 bio->bi_size = 0;
107 bio->bi_bdev = bdev;
108 bio->bi_sector = first_byte >> 9;
109 }
110 return bio;
111}
112
Chris Masond20f7042008-12-08 16:58:54 -0500113static int check_compressed_csum(struct inode *inode,
114 struct compressed_bio *cb,
115 u64 disk_start)
116{
117 int ret;
118 struct btrfs_root *root = BTRFS_I(inode)->root;
119 struct page *page;
120 unsigned long i;
121 char *kaddr;
122 u32 csum;
123 u32 *cb_sum = &cb->sums;
124
Christoph Hellwig6cbff002009-04-17 10:37:41 +0200125 if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
Chris Masond20f7042008-12-08 16:58:54 -0500126 return 0;
127
128 for (i = 0; i < cb->nr_pages; i++) {
129 page = cb->compressed_pages[i];
130 csum = ~(u32)0;
131
132 kaddr = kmap_atomic(page, KM_USER0);
133 csum = btrfs_csum_data(root, kaddr, csum, PAGE_CACHE_SIZE);
134 btrfs_csum_final(csum, (char *)&csum);
135 kunmap_atomic(kaddr, KM_USER0);
136
137 if (csum != *cb_sum) {
Chris Masond3977122009-01-05 21:25:51 -0500138 printk(KERN_INFO "btrfs csum failed ino %lu "
139 "extent %llu csum %u "
Chris Masond20f7042008-12-08 16:58:54 -0500140 "wanted %u mirror %d\n", inode->i_ino,
141 (unsigned long long)disk_start,
142 csum, *cb_sum, cb->mirror_num);
143 ret = -EIO;
144 goto fail;
145 }
146 cb_sum++;
147
148 }
149 ret = 0;
150fail:
151 return ret;
152}
153
Chris Masonc8b97812008-10-29 14:49:59 -0400154/* when we finish reading compressed pages from the disk, we
155 * decompress them and then run the bio end_io routines on the
156 * decompressed pages (in the inode address space).
157 *
158 * This allows the checksumming and other IO error handling routines
159 * to work normally
160 *
161 * The compressed pages are freed here, and it must be run
162 * in process context
163 */
164static void end_compressed_bio_read(struct bio *bio, int err)
165{
Chris Masonc8b97812008-10-29 14:49:59 -0400166 struct compressed_bio *cb = bio->bi_private;
167 struct inode *inode;
168 struct page *page;
169 unsigned long index;
170 int ret;
171
172 if (err)
173 cb->errors = 1;
174
175 /* if there are more bios still pending for this compressed
176 * extent, just exit
177 */
178 if (!atomic_dec_and_test(&cb->pending_bios))
179 goto out;
180
Chris Masond20f7042008-12-08 16:58:54 -0500181 inode = cb->inode;
182 ret = check_compressed_csum(inode, cb, (u64)bio->bi_sector << 9);
183 if (ret)
184 goto csum_failed;
185
Chris Masonc8b97812008-10-29 14:49:59 -0400186 /* ok, we're the last bio for this extent, lets start
187 * the decompression.
188 */
Chris Masonc8b97812008-10-29 14:49:59 -0400189 ret = btrfs_zlib_decompress_biovec(cb->compressed_pages,
190 cb->start,
191 cb->orig_bio->bi_io_vec,
192 cb->orig_bio->bi_vcnt,
193 cb->compressed_len);
Chris Masond20f7042008-12-08 16:58:54 -0500194csum_failed:
Chris Masonc8b97812008-10-29 14:49:59 -0400195 if (ret)
196 cb->errors = 1;
197
198 /* release the compressed pages */
199 index = 0;
200 for (index = 0; index < cb->nr_pages; index++) {
201 page = cb->compressed_pages[index];
202 page->mapping = NULL;
203 page_cache_release(page);
204 }
205
206 /* do io completion on the original bio */
Chris Mason771ed682008-11-06 22:02:51 -0500207 if (cb->errors) {
Chris Masonc8b97812008-10-29 14:49:59 -0400208 bio_io_error(cb->orig_bio);
Chris Masond20f7042008-12-08 16:58:54 -0500209 } else {
210 int bio_index = 0;
211 struct bio_vec *bvec = cb->orig_bio->bi_io_vec;
212
213 /*
214 * we have verified the checksum already, set page
215 * checked so the end_io handlers know about it
216 */
Chris Masond3977122009-01-05 21:25:51 -0500217 while (bio_index < cb->orig_bio->bi_vcnt) {
Chris Masond20f7042008-12-08 16:58:54 -0500218 SetPageChecked(bvec->bv_page);
219 bvec++;
220 bio_index++;
221 }
Chris Masonc8b97812008-10-29 14:49:59 -0400222 bio_endio(cb->orig_bio, 0);
Chris Masond20f7042008-12-08 16:58:54 -0500223 }
Chris Masonc8b97812008-10-29 14:49:59 -0400224
225 /* finally free the cb struct */
226 kfree(cb->compressed_pages);
227 kfree(cb);
228out:
229 bio_put(bio);
230}
231
232/*
233 * Clear the writeback bits on all of the file
234 * pages for a compressed write
235 */
236static noinline int end_compressed_writeback(struct inode *inode, u64 start,
237 unsigned long ram_size)
238{
239 unsigned long index = start >> PAGE_CACHE_SHIFT;
240 unsigned long end_index = (start + ram_size - 1) >> PAGE_CACHE_SHIFT;
241 struct page *pages[16];
242 unsigned long nr_pages = end_index - index + 1;
243 int i;
244 int ret;
245
Chris Masond3977122009-01-05 21:25:51 -0500246 while (nr_pages > 0) {
Chris Masonc8b97812008-10-29 14:49:59 -0400247 ret = find_get_pages_contig(inode->i_mapping, index,
Chris Mason5b050f02008-11-11 09:34:41 -0500248 min_t(unsigned long,
249 nr_pages, ARRAY_SIZE(pages)), pages);
Chris Masonc8b97812008-10-29 14:49:59 -0400250 if (ret == 0) {
251 nr_pages -= 1;
252 index += 1;
253 continue;
254 }
255 for (i = 0; i < ret; i++) {
256 end_page_writeback(pages[i]);
257 page_cache_release(pages[i]);
258 }
259 nr_pages -= ret;
260 index += ret;
261 }
262 /* the inode may be gone now */
263 return 0;
264}
265
266/*
267 * do the cleanup once all the compressed pages hit the disk.
268 * This will clear writeback on the file pages and free the compressed
269 * pages.
270 *
271 * This also calls the writeback end hooks for the file pages so that
272 * metadata and checksums can be updated in the file.
273 */
274static void end_compressed_bio_write(struct bio *bio, int err)
275{
276 struct extent_io_tree *tree;
277 struct compressed_bio *cb = bio->bi_private;
278 struct inode *inode;
279 struct page *page;
280 unsigned long index;
281
282 if (err)
283 cb->errors = 1;
284
285 /* if there are more bios still pending for this compressed
286 * extent, just exit
287 */
288 if (!atomic_dec_and_test(&cb->pending_bios))
289 goto out;
290
291 /* ok, we're the last bio for this extent, step one is to
292 * call back into the FS and do all the end_io operations
293 */
294 inode = cb->inode;
295 tree = &BTRFS_I(inode)->io_tree;
Chris Mason70b99e62008-10-31 12:46:39 -0400296 cb->compressed_pages[0]->mapping = cb->inode->i_mapping;
Chris Masonc8b97812008-10-29 14:49:59 -0400297 tree->ops->writepage_end_io_hook(cb->compressed_pages[0],
298 cb->start,
299 cb->start + cb->len - 1,
300 NULL, 1);
Chris Mason70b99e62008-10-31 12:46:39 -0400301 cb->compressed_pages[0]->mapping = NULL;
Chris Masonc8b97812008-10-29 14:49:59 -0400302
303 end_compressed_writeback(inode, cb->start, cb->len);
304 /* note, our inode could be gone now */
305
306 /*
307 * release the compressed pages, these came from alloc_page and
308 * are not attached to the inode at all
309 */
310 index = 0;
311 for (index = 0; index < cb->nr_pages; index++) {
312 page = cb->compressed_pages[index];
313 page->mapping = NULL;
314 page_cache_release(page);
315 }
316
317 /* finally free the cb struct */
318 kfree(cb->compressed_pages);
319 kfree(cb);
320out:
321 bio_put(bio);
322}
323
324/*
325 * worker function to build and submit bios for previously compressed pages.
326 * The corresponding pages in the inode should be marked for writeback
327 * and the compressed pages should have a reference on them for dropping
328 * when the IO is complete.
329 *
330 * This also checksums the file bytes and gets things ready for
331 * the end io hooks.
332 */
333int btrfs_submit_compressed_write(struct inode *inode, u64 start,
334 unsigned long len, u64 disk_start,
335 unsigned long compressed_len,
336 struct page **compressed_pages,
337 unsigned long nr_pages)
338{
339 struct bio *bio = NULL;
340 struct btrfs_root *root = BTRFS_I(inode)->root;
341 struct compressed_bio *cb;
342 unsigned long bytes_left;
343 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
344 int page_index = 0;
345 struct page *page;
346 u64 first_byte = disk_start;
347 struct block_device *bdev;
348 int ret;
349
350 WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1));
Chris Masond20f7042008-12-08 16:58:54 -0500351 cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
Chris Masonc8b97812008-10-29 14:49:59 -0400352 atomic_set(&cb->pending_bios, 0);
353 cb->errors = 0;
354 cb->inode = inode;
355 cb->start = start;
356 cb->len = len;
Chris Masond20f7042008-12-08 16:58:54 -0500357 cb->mirror_num = 0;
Chris Masonc8b97812008-10-29 14:49:59 -0400358 cb->compressed_pages = compressed_pages;
359 cb->compressed_len = compressed_len;
360 cb->orig_bio = NULL;
361 cb->nr_pages = nr_pages;
362
363 bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
364
Chris Masonc8b97812008-10-29 14:49:59 -0400365 bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS);
366 bio->bi_private = cb;
367 bio->bi_end_io = end_compressed_bio_write;
368 atomic_inc(&cb->pending_bios);
369
370 /* create and submit bios for the compressed pages */
371 bytes_left = compressed_len;
Chris Masoncfbc2462008-10-30 13:22:14 -0400372 for (page_index = 0; page_index < cb->nr_pages; page_index++) {
Chris Masonc8b97812008-10-29 14:49:59 -0400373 page = compressed_pages[page_index];
374 page->mapping = inode->i_mapping;
375 if (bio->bi_size)
376 ret = io_tree->ops->merge_bio_hook(page, 0,
377 PAGE_CACHE_SIZE,
378 bio, 0);
379 else
380 ret = 0;
381
Chris Mason70b99e62008-10-31 12:46:39 -0400382 page->mapping = NULL;
Chris Masonc8b97812008-10-29 14:49:59 -0400383 if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) <
384 PAGE_CACHE_SIZE) {
385 bio_get(bio);
386
Chris Masonaf09abf2008-11-07 12:35:44 -0500387 /*
388 * inc the count before we submit the bio so
389 * we know the end IO handler won't happen before
390 * we inc the count. Otherwise, the cb might get
391 * freed before we're done setting it up
392 */
393 atomic_inc(&cb->pending_bios);
Chris Masonc8b97812008-10-29 14:49:59 -0400394 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
395 BUG_ON(ret);
396
Chris Masond20f7042008-12-08 16:58:54 -0500397 ret = btrfs_csum_one_bio(root, inode, bio, start, 1);
398 BUG_ON(ret);
399
Chris Masonc8b97812008-10-29 14:49:59 -0400400 ret = btrfs_map_bio(root, WRITE, bio, 0, 1);
401 BUG_ON(ret);
402
403 bio_put(bio);
404
405 bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS);
Chris Masonc8b97812008-10-29 14:49:59 -0400406 bio->bi_private = cb;
407 bio->bi_end_io = end_compressed_bio_write;
408 bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
409 }
Chris Masoncfbc2462008-10-30 13:22:14 -0400410 if (bytes_left < PAGE_CACHE_SIZE) {
411 printk("bytes left %lu compress len %lu nr %lu\n",
412 bytes_left, cb->compressed_len, cb->nr_pages);
413 }
Chris Masonc8b97812008-10-29 14:49:59 -0400414 bytes_left -= PAGE_CACHE_SIZE;
415 first_byte += PAGE_CACHE_SIZE;
Chris Mason771ed682008-11-06 22:02:51 -0500416 cond_resched();
Chris Masonc8b97812008-10-29 14:49:59 -0400417 }
418 bio_get(bio);
419
420 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
421 BUG_ON(ret);
422
Chris Masond20f7042008-12-08 16:58:54 -0500423 ret = btrfs_csum_one_bio(root, inode, bio, start, 1);
424 BUG_ON(ret);
425
Chris Masonc8b97812008-10-29 14:49:59 -0400426 ret = btrfs_map_bio(root, WRITE, bio, 0, 1);
427 BUG_ON(ret);
428
429 bio_put(bio);
430 return 0;
431}
432
Chris Mason771ed682008-11-06 22:02:51 -0500433static noinline int add_ra_bio_pages(struct inode *inode,
434 u64 compressed_end,
435 struct compressed_bio *cb)
436{
437 unsigned long end_index;
438 unsigned long page_index;
439 u64 last_offset;
440 u64 isize = i_size_read(inode);
441 int ret;
442 struct page *page;
443 unsigned long nr_pages = 0;
444 struct extent_map *em;
445 struct address_space *mapping = inode->i_mapping;
Chris Mason771ed682008-11-06 22:02:51 -0500446 struct extent_map_tree *em_tree;
447 struct extent_io_tree *tree;
448 u64 end;
449 int misses = 0;
450
451 page = cb->orig_bio->bi_io_vec[cb->orig_bio->bi_vcnt - 1].bv_page;
452 last_offset = (page_offset(page) + PAGE_CACHE_SIZE);
453 em_tree = &BTRFS_I(inode)->extent_tree;
454 tree = &BTRFS_I(inode)->io_tree;
455
456 if (isize == 0)
457 return 0;
458
459 end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
460
Chris Masond3977122009-01-05 21:25:51 -0500461 while (last_offset < compressed_end) {
Chris Mason771ed682008-11-06 22:02:51 -0500462 page_index = last_offset >> PAGE_CACHE_SHIFT;
463
464 if (page_index > end_index)
465 break;
466
467 rcu_read_lock();
468 page = radix_tree_lookup(&mapping->page_tree, page_index);
469 rcu_read_unlock();
470 if (page) {
471 misses++;
472 if (misses > 4)
473 break;
474 goto next;
475 }
476
Nick Piggin28ecb6092010-03-17 13:31:04 +0000477 page = __page_cache_alloc(mapping_gfp_mask(mapping) &
478 ~__GFP_FS);
Chris Mason771ed682008-11-06 22:02:51 -0500479 if (!page)
480 break;
481
Nick Piggin28ecb6092010-03-17 13:31:04 +0000482 if (add_to_page_cache_lru(page, mapping, page_index,
483 GFP_NOFS)) {
Chris Mason771ed682008-11-06 22:02:51 -0500484 page_cache_release(page);
485 goto next;
486 }
487
Chris Mason771ed682008-11-06 22:02:51 -0500488 end = last_offset + PAGE_CACHE_SIZE - 1;
489 /*
490 * at this point, we have a locked page in the page cache
491 * for these bytes in the file. But, we have to make
492 * sure they map to this compressed extent on disk.
493 */
494 set_page_extent_mapped(page);
495 lock_extent(tree, last_offset, end, GFP_NOFS);
Chris Mason890871b2009-09-02 16:24:52 -0400496 read_lock(&em_tree->lock);
Chris Mason771ed682008-11-06 22:02:51 -0500497 em = lookup_extent_mapping(em_tree, last_offset,
498 PAGE_CACHE_SIZE);
Chris Mason890871b2009-09-02 16:24:52 -0400499 read_unlock(&em_tree->lock);
Chris Mason771ed682008-11-06 22:02:51 -0500500
501 if (!em || last_offset < em->start ||
502 (last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) ||
503 (em->block_start >> 9) != cb->orig_bio->bi_sector) {
504 free_extent_map(em);
505 unlock_extent(tree, last_offset, end, GFP_NOFS);
506 unlock_page(page);
507 page_cache_release(page);
508 break;
509 }
510 free_extent_map(em);
511
512 if (page->index == end_index) {
513 char *userpage;
514 size_t zero_offset = isize & (PAGE_CACHE_SIZE - 1);
515
516 if (zero_offset) {
517 int zeros;
518 zeros = PAGE_CACHE_SIZE - zero_offset;
519 userpage = kmap_atomic(page, KM_USER0);
520 memset(userpage + zero_offset, 0, zeros);
521 flush_dcache_page(page);
522 kunmap_atomic(userpage, KM_USER0);
523 }
524 }
525
526 ret = bio_add_page(cb->orig_bio, page,
527 PAGE_CACHE_SIZE, 0);
528
529 if (ret == PAGE_CACHE_SIZE) {
530 nr_pages++;
531 page_cache_release(page);
532 } else {
533 unlock_extent(tree, last_offset, end, GFP_NOFS);
534 unlock_page(page);
535 page_cache_release(page);
536 break;
537 }
538next:
539 last_offset += PAGE_CACHE_SIZE;
540 }
Chris Mason771ed682008-11-06 22:02:51 -0500541 return 0;
542}
543
Chris Masonc8b97812008-10-29 14:49:59 -0400544/*
545 * for a compressed read, the bio we get passed has all the inode pages
546 * in it. We don't actually do IO on those pages but allocate new ones
547 * to hold the compressed pages on disk.
548 *
549 * bio->bi_sector points to the compressed extent on disk
550 * bio->bi_io_vec points to all of the inode pages
551 * bio->bi_vcnt is a count of pages
552 *
553 * After the compressed pages are read, we copy the bytes into the
554 * bio we were passed and then call the bio end_io calls
555 */
556int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
557 int mirror_num, unsigned long bio_flags)
558{
559 struct extent_io_tree *tree;
560 struct extent_map_tree *em_tree;
561 struct compressed_bio *cb;
562 struct btrfs_root *root = BTRFS_I(inode)->root;
563 unsigned long uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE;
564 unsigned long compressed_len;
565 unsigned long nr_pages;
566 unsigned long page_index;
567 struct page *page;
568 struct block_device *bdev;
569 struct bio *comp_bio;
570 u64 cur_disk_byte = (u64)bio->bi_sector << 9;
Chris Masone04ca622008-11-10 11:44:58 -0500571 u64 em_len;
572 u64 em_start;
Chris Masonc8b97812008-10-29 14:49:59 -0400573 struct extent_map *em;
574 int ret;
Chris Masond20f7042008-12-08 16:58:54 -0500575 u32 *sums;
Chris Masonc8b97812008-10-29 14:49:59 -0400576
577 tree = &BTRFS_I(inode)->io_tree;
578 em_tree = &BTRFS_I(inode)->extent_tree;
579
580 /* we need the actual starting offset of this extent in the file */
Chris Mason890871b2009-09-02 16:24:52 -0400581 read_lock(&em_tree->lock);
Chris Masonc8b97812008-10-29 14:49:59 -0400582 em = lookup_extent_mapping(em_tree,
583 page_offset(bio->bi_io_vec->bv_page),
584 PAGE_CACHE_SIZE);
Chris Mason890871b2009-09-02 16:24:52 -0400585 read_unlock(&em_tree->lock);
Chris Masonc8b97812008-10-29 14:49:59 -0400586
Chris Masond20f7042008-12-08 16:58:54 -0500587 compressed_len = em->block_len;
588 cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
Chris Masonc8b97812008-10-29 14:49:59 -0400589 atomic_set(&cb->pending_bios, 0);
590 cb->errors = 0;
591 cb->inode = inode;
Chris Masond20f7042008-12-08 16:58:54 -0500592 cb->mirror_num = mirror_num;
593 sums = &cb->sums;
Chris Masonc8b97812008-10-29 14:49:59 -0400594
Yan Zhengff5b7ee2008-11-10 07:34:43 -0500595 cb->start = em->orig_start;
Chris Masone04ca622008-11-10 11:44:58 -0500596 em_len = em->len;
597 em_start = em->start;
Chris Masond20f7042008-12-08 16:58:54 -0500598
Chris Masonc8b97812008-10-29 14:49:59 -0400599 free_extent_map(em);
Chris Masone04ca622008-11-10 11:44:58 -0500600 em = NULL;
Chris Masonc8b97812008-10-29 14:49:59 -0400601
602 cb->len = uncompressed_len;
603 cb->compressed_len = compressed_len;
604 cb->orig_bio = bio;
605
606 nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) /
607 PAGE_CACHE_SIZE;
608 cb->compressed_pages = kmalloc(sizeof(struct page *) * nr_pages,
609 GFP_NOFS);
610 bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
611
612 for (page_index = 0; page_index < nr_pages; page_index++) {
613 cb->compressed_pages[page_index] = alloc_page(GFP_NOFS |
614 __GFP_HIGHMEM);
615 }
616 cb->nr_pages = nr_pages;
617
Chris Masone04ca622008-11-10 11:44:58 -0500618 add_ra_bio_pages(inode, em_start + em_len, cb);
Chris Mason771ed682008-11-06 22:02:51 -0500619
Chris Mason771ed682008-11-06 22:02:51 -0500620 /* include any pages we added in add_ra-bio_pages */
621 uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE;
622 cb->len = uncompressed_len;
623
Chris Masonc8b97812008-10-29 14:49:59 -0400624 comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS);
625 comp_bio->bi_private = cb;
626 comp_bio->bi_end_io = end_compressed_bio_read;
627 atomic_inc(&cb->pending_bios);
628
629 for (page_index = 0; page_index < nr_pages; page_index++) {
630 page = cb->compressed_pages[page_index];
631 page->mapping = inode->i_mapping;
Chris Masond20f7042008-12-08 16:58:54 -0500632 page->index = em_start >> PAGE_CACHE_SHIFT;
633
Chris Masonc8b97812008-10-29 14:49:59 -0400634 if (comp_bio->bi_size)
635 ret = tree->ops->merge_bio_hook(page, 0,
636 PAGE_CACHE_SIZE,
637 comp_bio, 0);
638 else
639 ret = 0;
640
Chris Mason70b99e62008-10-31 12:46:39 -0400641 page->mapping = NULL;
Chris Masonc8b97812008-10-29 14:49:59 -0400642 if (ret || bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0) <
643 PAGE_CACHE_SIZE) {
644 bio_get(comp_bio);
645
646 ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0);
647 BUG_ON(ret);
648
Chris Masonaf09abf2008-11-07 12:35:44 -0500649 /*
650 * inc the count before we submit the bio so
651 * we know the end IO handler won't happen before
652 * we inc the count. Otherwise, the cb might get
653 * freed before we're done setting it up
654 */
655 atomic_inc(&cb->pending_bios);
656
Christoph Hellwig6cbff002009-04-17 10:37:41 +0200657 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
Chris Masond20f7042008-12-08 16:58:54 -0500658 btrfs_lookup_bio_sums(root, inode, comp_bio,
659 sums);
660 }
661 sums += (comp_bio->bi_size + root->sectorsize - 1) /
662 root->sectorsize;
663
664 ret = btrfs_map_bio(root, READ, comp_bio,
665 mirror_num, 0);
Chris Masonc8b97812008-10-29 14:49:59 -0400666 BUG_ON(ret);
667
668 bio_put(comp_bio);
669
670 comp_bio = compressed_bio_alloc(bdev, cur_disk_byte,
671 GFP_NOFS);
Chris Mason771ed682008-11-06 22:02:51 -0500672 comp_bio->bi_private = cb;
673 comp_bio->bi_end_io = end_compressed_bio_read;
674
675 bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0);
Chris Masonc8b97812008-10-29 14:49:59 -0400676 }
677 cur_disk_byte += PAGE_CACHE_SIZE;
678 }
679 bio_get(comp_bio);
680
681 ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0);
682 BUG_ON(ret);
683
Christoph Hellwig6cbff002009-04-17 10:37:41 +0200684 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM))
Chris Masond20f7042008-12-08 16:58:54 -0500685 btrfs_lookup_bio_sums(root, inode, comp_bio, sums);
Chris Masond20f7042008-12-08 16:58:54 -0500686
687 ret = btrfs_map_bio(root, READ, comp_bio, mirror_num, 0);
Chris Masonc8b97812008-10-29 14:49:59 -0400688 BUG_ON(ret);
689
690 bio_put(comp_bio);
691 return 0;
692}