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/version.h>
36 #include <linux/pagevec.h>
39 #include "transaction.h"
40 #include "btrfs_inode.h"
42 #include "ordered-data.h"
44 #include "compression.h"
45 #include "extent_io.h"
46 #include "extent_map.h"
48 struct compressed_bio
{
49 /* number of bios pending for this compressed extent */
50 atomic_t pending_bios
;
52 /* the pages with the compressed data on them */
53 struct page
**compressed_pages
;
55 /* inode that owns this data */
58 /* starting offset in the inode for our pages */
61 /* number of bytes in the inode we're working on */
64 /* number of bytes on disk */
65 unsigned long compressed_len
;
67 /* number of compressed pages in the array */
68 unsigned long nr_pages
;
73 /* for reads, this is the bio we are copying the data into */
77 static struct bio
*compressed_bio_alloc(struct block_device
*bdev
,
78 u64 first_byte
, gfp_t gfp_flags
)
83 nr_vecs
= bio_get_nr_vecs(bdev
);
84 bio
= bio_alloc(gfp_flags
, nr_vecs
);
86 if (bio
== NULL
&& (current
->flags
& PF_MEMALLOC
)) {
87 while (!bio
&& (nr_vecs
/= 2))
88 bio
= bio_alloc(gfp_flags
, nr_vecs
);
94 bio
->bi_sector
= first_byte
>> 9;
99 /* when we finish reading compressed pages from the disk, we
100 * decompress them and then run the bio end_io routines on the
101 * decompressed pages (in the inode address space).
103 * This allows the checksumming and other IO error handling routines
106 * The compressed pages are freed here, and it must be run
109 static void end_compressed_bio_read(struct bio
*bio
, int err
)
111 struct extent_io_tree
*tree
;
112 struct compressed_bio
*cb
= bio
->bi_private
;
121 /* if there are more bios still pending for this compressed
124 if (!atomic_dec_and_test(&cb
->pending_bios
))
127 /* ok, we're the last bio for this extent, lets start
131 tree
= &BTRFS_I(inode
)->io_tree
;
132 ret
= btrfs_zlib_decompress_biovec(cb
->compressed_pages
,
134 cb
->orig_bio
->bi_io_vec
,
135 cb
->orig_bio
->bi_vcnt
,
140 /* release the compressed pages */
142 for (index
= 0; index
< cb
->nr_pages
; index
++) {
143 page
= cb
->compressed_pages
[index
];
144 page
->mapping
= NULL
;
145 page_cache_release(page
);
148 /* do io completion on the original bio */
150 bio_io_error(cb
->orig_bio
);
152 bio_endio(cb
->orig_bio
, 0);
154 /* finally free the cb struct */
155 kfree(cb
->compressed_pages
);
162 * Clear the writeback bits on all of the file
163 * pages for a compressed write
165 static noinline
int end_compressed_writeback(struct inode
*inode
, u64 start
,
166 unsigned long ram_size
)
168 unsigned long index
= start
>> PAGE_CACHE_SHIFT
;
169 unsigned long end_index
= (start
+ ram_size
- 1) >> PAGE_CACHE_SHIFT
;
170 struct page
*pages
[16];
171 unsigned long nr_pages
= end_index
- index
+ 1;
175 while(nr_pages
> 0) {
176 ret
= find_get_pages_contig(inode
->i_mapping
, index
,
177 min(nr_pages
, ARRAY_SIZE(pages
)), pages
);
183 for (i
= 0; i
< ret
; i
++) {
184 end_page_writeback(pages
[i
]);
185 page_cache_release(pages
[i
]);
190 /* the inode may be gone now */
195 * do the cleanup once all the compressed pages hit the disk.
196 * This will clear writeback on the file pages and free the compressed
199 * This also calls the writeback end hooks for the file pages so that
200 * metadata and checksums can be updated in the file.
202 static void end_compressed_bio_write(struct bio
*bio
, int err
)
204 struct extent_io_tree
*tree
;
205 struct compressed_bio
*cb
= bio
->bi_private
;
213 /* if there are more bios still pending for this compressed
216 if (!atomic_dec_and_test(&cb
->pending_bios
))
219 /* ok, we're the last bio for this extent, step one is to
220 * call back into the FS and do all the end_io operations
223 tree
= &BTRFS_I(inode
)->io_tree
;
224 cb
->compressed_pages
[0]->mapping
= cb
->inode
->i_mapping
;
225 tree
->ops
->writepage_end_io_hook(cb
->compressed_pages
[0],
227 cb
->start
+ cb
->len
- 1,
229 cb
->compressed_pages
[0]->mapping
= NULL
;
231 end_compressed_writeback(inode
, cb
->start
, cb
->len
);
232 /* note, our inode could be gone now */
235 * release the compressed pages, these came from alloc_page and
236 * are not attached to the inode at all
239 for (index
= 0; index
< cb
->nr_pages
; index
++) {
240 page
= cb
->compressed_pages
[index
];
241 page
->mapping
= NULL
;
242 page_cache_release(page
);
245 /* finally free the cb struct */
246 kfree(cb
->compressed_pages
);
253 * worker function to build and submit bios for previously compressed pages.
254 * The corresponding pages in the inode should be marked for writeback
255 * and the compressed pages should have a reference on them for dropping
256 * when the IO is complete.
258 * This also checksums the file bytes and gets things ready for
261 int btrfs_submit_compressed_write(struct inode
*inode
, u64 start
,
262 unsigned long len
, u64 disk_start
,
263 unsigned long compressed_len
,
264 struct page
**compressed_pages
,
265 unsigned long nr_pages
)
267 struct bio
*bio
= NULL
;
268 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
269 struct compressed_bio
*cb
;
270 unsigned long bytes_left
;
271 struct extent_io_tree
*io_tree
= &BTRFS_I(inode
)->io_tree
;
274 u64 first_byte
= disk_start
;
275 struct block_device
*bdev
;
278 WARN_ON(start
& ((u64
)PAGE_CACHE_SIZE
- 1));
279 cb
= kmalloc(sizeof(*cb
), GFP_NOFS
);
280 atomic_set(&cb
->pending_bios
, 0);
285 cb
->compressed_pages
= compressed_pages
;
286 cb
->compressed_len
= compressed_len
;
288 cb
->nr_pages
= nr_pages
;
290 bdev
= BTRFS_I(inode
)->root
->fs_info
->fs_devices
->latest_bdev
;
292 ret
= btrfs_csum_file_bytes(root
, inode
, start
, len
);
295 bio
= compressed_bio_alloc(bdev
, first_byte
, GFP_NOFS
);
296 bio
->bi_private
= cb
;
297 bio
->bi_end_io
= end_compressed_bio_write
;
298 atomic_inc(&cb
->pending_bios
);
300 /* create and submit bios for the compressed pages */
301 bytes_left
= compressed_len
;
302 for (page_index
= 0; page_index
< cb
->nr_pages
; page_index
++) {
303 page
= compressed_pages
[page_index
];
304 page
->mapping
= inode
->i_mapping
;
306 ret
= io_tree
->ops
->merge_bio_hook(page
, 0,
312 page
->mapping
= NULL
;
313 if (ret
|| bio_add_page(bio
, page
, PAGE_CACHE_SIZE
, 0) <
318 * inc the count before we submit the bio so
319 * we know the end IO handler won't happen before
320 * we inc the count. Otherwise, the cb might get
321 * freed before we're done setting it up
323 atomic_inc(&cb
->pending_bios
);
324 ret
= btrfs_bio_wq_end_io(root
->fs_info
, bio
, 0);
327 ret
= btrfs_map_bio(root
, WRITE
, bio
, 0, 1);
332 bio
= compressed_bio_alloc(bdev
, first_byte
, GFP_NOFS
);
333 bio
->bi_private
= cb
;
334 bio
->bi_end_io
= end_compressed_bio_write
;
335 bio_add_page(bio
, page
, PAGE_CACHE_SIZE
, 0);
337 if (bytes_left
< PAGE_CACHE_SIZE
) {
338 printk("bytes left %lu compress len %lu nr %lu\n",
339 bytes_left
, cb
->compressed_len
, cb
->nr_pages
);
341 bytes_left
-= PAGE_CACHE_SIZE
;
342 first_byte
+= PAGE_CACHE_SIZE
;
347 ret
= btrfs_bio_wq_end_io(root
->fs_info
, bio
, 0);
350 ret
= btrfs_map_bio(root
, WRITE
, bio
, 0, 1);
357 static noinline
int add_ra_bio_pages(struct inode
*inode
,
359 struct compressed_bio
*cb
)
361 unsigned long end_index
;
362 unsigned long page_index
;
364 u64 isize
= i_size_read(inode
);
367 unsigned long nr_pages
= 0;
368 struct extent_map
*em
;
369 struct address_space
*mapping
= inode
->i_mapping
;
371 struct extent_map_tree
*em_tree
;
372 struct extent_io_tree
*tree
;
376 page
= cb
->orig_bio
->bi_io_vec
[cb
->orig_bio
->bi_vcnt
- 1].bv_page
;
377 last_offset
= (page_offset(page
) + PAGE_CACHE_SIZE
);
378 em_tree
= &BTRFS_I(inode
)->extent_tree
;
379 tree
= &BTRFS_I(inode
)->io_tree
;
384 end_index
= (i_size_read(inode
) - 1) >> PAGE_CACHE_SHIFT
;
386 pagevec_init(&pvec
, 0);
387 while(last_offset
< compressed_end
) {
388 page_index
= last_offset
>> PAGE_CACHE_SHIFT
;
390 if (page_index
> end_index
)
394 page
= radix_tree_lookup(&mapping
->page_tree
, page_index
);
403 page
= alloc_page(mapping_gfp_mask(mapping
) | GFP_NOFS
);
407 page
->index
= page_index
;
409 * what we want to do here is call add_to_page_cache_lru,
410 * but that isn't exported, so we reproduce it here
412 if (add_to_page_cache(page
, mapping
,
413 page
->index
, GFP_NOFS
)) {
414 page_cache_release(page
);
418 /* open coding of lru_cache_add, also not exported */
419 page_cache_get(page
);
420 if (!pagevec_add(&pvec
, page
))
421 __pagevec_lru_add(&pvec
);
423 end
= last_offset
+ PAGE_CACHE_SIZE
- 1;
425 * at this point, we have a locked page in the page cache
426 * for these bytes in the file. But, we have to make
427 * sure they map to this compressed extent on disk.
429 set_page_extent_mapped(page
);
430 lock_extent(tree
, last_offset
, end
, GFP_NOFS
);
431 spin_lock(&em_tree
->lock
);
432 em
= lookup_extent_mapping(em_tree
, last_offset
,
434 spin_unlock(&em_tree
->lock
);
436 if (!em
|| last_offset
< em
->start
||
437 (last_offset
+ PAGE_CACHE_SIZE
> extent_map_end(em
)) ||
438 (em
->block_start
>> 9) != cb
->orig_bio
->bi_sector
) {
440 unlock_extent(tree
, last_offset
, end
, GFP_NOFS
);
442 page_cache_release(page
);
447 if (page
->index
== end_index
) {
449 size_t zero_offset
= isize
& (PAGE_CACHE_SIZE
- 1);
453 zeros
= PAGE_CACHE_SIZE
- zero_offset
;
454 userpage
= kmap_atomic(page
, KM_USER0
);
455 memset(userpage
+ zero_offset
, 0, zeros
);
456 flush_dcache_page(page
);
457 kunmap_atomic(userpage
, KM_USER0
);
461 ret
= bio_add_page(cb
->orig_bio
, page
,
464 if (ret
== PAGE_CACHE_SIZE
) {
466 page_cache_release(page
);
468 unlock_extent(tree
, last_offset
, end
, GFP_NOFS
);
470 page_cache_release(page
);
474 last_offset
+= PAGE_CACHE_SIZE
;
476 if (pagevec_count(&pvec
))
477 __pagevec_lru_add(&pvec
);
482 * for a compressed read, the bio we get passed has all the inode pages
483 * in it. We don't actually do IO on those pages but allocate new ones
484 * to hold the compressed pages on disk.
486 * bio->bi_sector points to the compressed extent on disk
487 * bio->bi_io_vec points to all of the inode pages
488 * bio->bi_vcnt is a count of pages
490 * After the compressed pages are read, we copy the bytes into the
491 * bio we were passed and then call the bio end_io calls
493 int btrfs_submit_compressed_read(struct inode
*inode
, struct bio
*bio
,
494 int mirror_num
, unsigned long bio_flags
)
496 struct extent_io_tree
*tree
;
497 struct extent_map_tree
*em_tree
;
498 struct compressed_bio
*cb
;
499 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
500 unsigned long uncompressed_len
= bio
->bi_vcnt
* PAGE_CACHE_SIZE
;
501 unsigned long compressed_len
;
502 unsigned long nr_pages
;
503 unsigned long page_index
;
505 struct block_device
*bdev
;
506 struct bio
*comp_bio
;
507 u64 cur_disk_byte
= (u64
)bio
->bi_sector
<< 9;
508 struct extent_map
*em
;
511 tree
= &BTRFS_I(inode
)->io_tree
;
512 em_tree
= &BTRFS_I(inode
)->extent_tree
;
514 /* we need the actual starting offset of this extent in the file */
515 spin_lock(&em_tree
->lock
);
516 em
= lookup_extent_mapping(em_tree
,
517 page_offset(bio
->bi_io_vec
->bv_page
),
519 spin_unlock(&em_tree
->lock
);
521 cb
= kmalloc(sizeof(*cb
), GFP_NOFS
);
522 atomic_set(&cb
->pending_bios
, 0);
526 cb
->start
= em
->orig_start
;
527 compressed_len
= em
->block_len
;
530 cb
->len
= uncompressed_len
;
531 cb
->compressed_len
= compressed_len
;
534 nr_pages
= (compressed_len
+ PAGE_CACHE_SIZE
- 1) /
536 cb
->compressed_pages
= kmalloc(sizeof(struct page
*) * nr_pages
,
538 bdev
= BTRFS_I(inode
)->root
->fs_info
->fs_devices
->latest_bdev
;
540 for (page_index
= 0; page_index
< nr_pages
; page_index
++) {
541 cb
->compressed_pages
[page_index
] = alloc_page(GFP_NOFS
|
544 cb
->nr_pages
= nr_pages
;
546 add_ra_bio_pages(inode
, em
->start
+ em
->len
, cb
);
548 if (!btrfs_test_opt(root
, NODATASUM
) &&
549 !btrfs_test_flag(inode
, NODATASUM
)) {
550 btrfs_lookup_bio_sums(root
, inode
, cb
->orig_bio
);
553 /* include any pages we added in add_ra-bio_pages */
554 uncompressed_len
= bio
->bi_vcnt
* PAGE_CACHE_SIZE
;
555 cb
->len
= uncompressed_len
;
557 comp_bio
= compressed_bio_alloc(bdev
, cur_disk_byte
, GFP_NOFS
);
558 comp_bio
->bi_private
= cb
;
559 comp_bio
->bi_end_io
= end_compressed_bio_read
;
560 atomic_inc(&cb
->pending_bios
);
562 for (page_index
= 0; page_index
< nr_pages
; page_index
++) {
563 page
= cb
->compressed_pages
[page_index
];
564 page
->mapping
= inode
->i_mapping
;
565 if (comp_bio
->bi_size
)
566 ret
= tree
->ops
->merge_bio_hook(page
, 0,
572 page
->mapping
= NULL
;
573 if (ret
|| bio_add_page(comp_bio
, page
, PAGE_CACHE_SIZE
, 0) <
577 ret
= btrfs_bio_wq_end_io(root
->fs_info
, comp_bio
, 0);
581 * inc the count before we submit the bio so
582 * we know the end IO handler won't happen before
583 * we inc the count. Otherwise, the cb might get
584 * freed before we're done setting it up
586 atomic_inc(&cb
->pending_bios
);
588 ret
= btrfs_map_bio(root
, READ
, comp_bio
, 0, 0);
593 comp_bio
= compressed_bio_alloc(bdev
, cur_disk_byte
,
595 comp_bio
->bi_private
= cb
;
596 comp_bio
->bi_end_io
= end_compressed_bio_read
;
598 bio_add_page(comp_bio
, page
, PAGE_CACHE_SIZE
, 0);
600 cur_disk_byte
+= PAGE_CACHE_SIZE
;
604 ret
= btrfs_bio_wq_end_io(root
->fs_info
, comp_bio
, 0);
607 ret
= btrfs_map_bio(root
, READ
, comp_bio
, 0, 0);
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