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c8b97818 CM |
1 | /* |
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> | |
35 | #include <linux/version.h> | |
36 | #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" | |
42 | #include "compat.h" | |
43 | #include "compression.h" | |
44 | #include "extent_io.h" | |
45 | #include "extent_map.h" | |
46 | ||
47 | struct 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; | |
71 | ||
72 | /* for reads, this is the bio we are copying the data into */ | |
73 | struct bio *orig_bio; | |
74 | }; | |
75 | ||
76 | static struct bio *compressed_bio_alloc(struct block_device *bdev, | |
77 | u64 first_byte, gfp_t gfp_flags) | |
78 | { | |
79 | struct bio *bio; | |
80 | int nr_vecs; | |
81 | ||
82 | nr_vecs = bio_get_nr_vecs(bdev); | |
83 | bio = bio_alloc(gfp_flags, nr_vecs); | |
84 | ||
85 | if (bio == NULL && (current->flags & PF_MEMALLOC)) { | |
86 | while (!bio && (nr_vecs /= 2)) | |
87 | bio = bio_alloc(gfp_flags, nr_vecs); | |
88 | } | |
89 | ||
90 | if (bio) { | |
91 | bio->bi_size = 0; | |
92 | bio->bi_bdev = bdev; | |
93 | bio->bi_sector = first_byte >> 9; | |
94 | } | |
95 | return bio; | |
96 | } | |
97 | ||
98 | /* when we finish reading compressed pages from the disk, we | |
99 | * decompress them and then run the bio end_io routines on the | |
100 | * decompressed pages (in the inode address space). | |
101 | * | |
102 | * This allows the checksumming and other IO error handling routines | |
103 | * to work normally | |
104 | * | |
105 | * The compressed pages are freed here, and it must be run | |
106 | * in process context | |
107 | */ | |
108 | static void end_compressed_bio_read(struct bio *bio, int err) | |
109 | { | |
110 | struct extent_io_tree *tree; | |
111 | struct compressed_bio *cb = bio->bi_private; | |
112 | struct inode *inode; | |
113 | struct page *page; | |
114 | unsigned long index; | |
115 | int ret; | |
116 | ||
117 | if (err) | |
118 | cb->errors = 1; | |
119 | ||
120 | /* if there are more bios still pending for this compressed | |
121 | * extent, just exit | |
122 | */ | |
123 | if (!atomic_dec_and_test(&cb->pending_bios)) | |
124 | goto out; | |
125 | ||
126 | /* ok, we're the last bio for this extent, lets start | |
127 | * the decompression. | |
128 | */ | |
129 | inode = cb->inode; | |
130 | tree = &BTRFS_I(inode)->io_tree; | |
131 | ret = btrfs_zlib_decompress_biovec(cb->compressed_pages, | |
132 | cb->start, | |
133 | cb->orig_bio->bi_io_vec, | |
134 | cb->orig_bio->bi_vcnt, | |
135 | cb->compressed_len); | |
136 | if (ret) | |
137 | cb->errors = 1; | |
138 | ||
139 | /* release the compressed pages */ | |
140 | index = 0; | |
141 | for (index = 0; index < cb->nr_pages; index++) { | |
142 | page = cb->compressed_pages[index]; | |
143 | page->mapping = NULL; | |
144 | page_cache_release(page); | |
145 | } | |
146 | ||
147 | /* do io completion on the original bio */ | |
148 | if (cb->errors) | |
149 | bio_io_error(cb->orig_bio); | |
150 | else | |
151 | bio_endio(cb->orig_bio, 0); | |
152 | ||
153 | /* finally free the cb struct */ | |
154 | kfree(cb->compressed_pages); | |
155 | kfree(cb); | |
156 | out: | |
157 | bio_put(bio); | |
158 | } | |
159 | ||
160 | /* | |
161 | * Clear the writeback bits on all of the file | |
162 | * pages for a compressed write | |
163 | */ | |
164 | static noinline int end_compressed_writeback(struct inode *inode, u64 start, | |
165 | unsigned long ram_size) | |
166 | { | |
167 | unsigned long index = start >> PAGE_CACHE_SHIFT; | |
168 | unsigned long end_index = (start + ram_size - 1) >> PAGE_CACHE_SHIFT; | |
169 | struct page *pages[16]; | |
170 | unsigned long nr_pages = end_index - index + 1; | |
171 | int i; | |
172 | int ret; | |
173 | ||
174 | while(nr_pages > 0) { | |
175 | ret = find_get_pages_contig(inode->i_mapping, index, | |
176 | min(nr_pages, ARRAY_SIZE(pages)), pages); | |
177 | if (ret == 0) { | |
178 | nr_pages -= 1; | |
179 | index += 1; | |
180 | continue; | |
181 | } | |
182 | for (i = 0; i < ret; i++) { | |
183 | end_page_writeback(pages[i]); | |
184 | page_cache_release(pages[i]); | |
185 | } | |
186 | nr_pages -= ret; | |
187 | index += ret; | |
188 | } | |
189 | /* the inode may be gone now */ | |
190 | return 0; | |
191 | } | |
192 | ||
193 | /* | |
194 | * do the cleanup once all the compressed pages hit the disk. | |
195 | * This will clear writeback on the file pages and free the compressed | |
196 | * pages. | |
197 | * | |
198 | * This also calls the writeback end hooks for the file pages so that | |
199 | * metadata and checksums can be updated in the file. | |
200 | */ | |
201 | static void end_compressed_bio_write(struct bio *bio, int err) | |
202 | { | |
203 | struct extent_io_tree *tree; | |
204 | struct compressed_bio *cb = bio->bi_private; | |
205 | struct inode *inode; | |
206 | struct page *page; | |
207 | unsigned long index; | |
208 | ||
209 | if (err) | |
210 | cb->errors = 1; | |
211 | ||
212 | /* if there are more bios still pending for this compressed | |
213 | * extent, just exit | |
214 | */ | |
215 | if (!atomic_dec_and_test(&cb->pending_bios)) | |
216 | goto out; | |
217 | ||
218 | /* ok, we're the last bio for this extent, step one is to | |
219 | * call back into the FS and do all the end_io operations | |
220 | */ | |
221 | inode = cb->inode; | |
222 | tree = &BTRFS_I(inode)->io_tree; | |
223 | tree->ops->writepage_end_io_hook(cb->compressed_pages[0], | |
224 | cb->start, | |
225 | cb->start + cb->len - 1, | |
226 | NULL, 1); | |
227 | ||
228 | end_compressed_writeback(inode, cb->start, cb->len); | |
229 | /* note, our inode could be gone now */ | |
230 | ||
231 | /* | |
232 | * release the compressed pages, these came from alloc_page and | |
233 | * are not attached to the inode at all | |
234 | */ | |
235 | index = 0; | |
236 | for (index = 0; index < cb->nr_pages; index++) { | |
237 | page = cb->compressed_pages[index]; | |
238 | page->mapping = NULL; | |
239 | page_cache_release(page); | |
240 | } | |
241 | ||
242 | /* finally free the cb struct */ | |
243 | kfree(cb->compressed_pages); | |
244 | kfree(cb); | |
245 | out: | |
246 | bio_put(bio); | |
247 | } | |
248 | ||
249 | /* | |
250 | * worker function to build and submit bios for previously compressed pages. | |
251 | * The corresponding pages in the inode should be marked for writeback | |
252 | * and the compressed pages should have a reference on them for dropping | |
253 | * when the IO is complete. | |
254 | * | |
255 | * This also checksums the file bytes and gets things ready for | |
256 | * the end io hooks. | |
257 | */ | |
258 | int btrfs_submit_compressed_write(struct inode *inode, u64 start, | |
259 | unsigned long len, u64 disk_start, | |
260 | unsigned long compressed_len, | |
261 | struct page **compressed_pages, | |
262 | unsigned long nr_pages) | |
263 | { | |
264 | struct bio *bio = NULL; | |
265 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
266 | struct compressed_bio *cb; | |
267 | unsigned long bytes_left; | |
268 | struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; | |
269 | int page_index = 0; | |
270 | struct page *page; | |
271 | u64 first_byte = disk_start; | |
272 | struct block_device *bdev; | |
273 | int ret; | |
274 | ||
275 | WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1)); | |
276 | cb = kmalloc(sizeof(*cb), GFP_NOFS); | |
277 | atomic_set(&cb->pending_bios, 0); | |
278 | cb->errors = 0; | |
279 | cb->inode = inode; | |
280 | cb->start = start; | |
281 | cb->len = len; | |
282 | cb->compressed_pages = compressed_pages; | |
283 | cb->compressed_len = compressed_len; | |
284 | cb->orig_bio = NULL; | |
285 | cb->nr_pages = nr_pages; | |
286 | ||
287 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; | |
288 | ||
289 | ret = btrfs_csum_file_bytes(root, inode, start, len); | |
290 | BUG_ON(ret); | |
291 | ||
292 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); | |
293 | bio->bi_private = cb; | |
294 | bio->bi_end_io = end_compressed_bio_write; | |
295 | atomic_inc(&cb->pending_bios); | |
296 | ||
297 | /* create and submit bios for the compressed pages */ | |
298 | bytes_left = compressed_len; | |
299 | while(bytes_left > 0) { | |
300 | page = compressed_pages[page_index]; | |
301 | page->mapping = inode->i_mapping; | |
302 | if (bio->bi_size) | |
303 | ret = io_tree->ops->merge_bio_hook(page, 0, | |
304 | PAGE_CACHE_SIZE, | |
305 | bio, 0); | |
306 | else | |
307 | ret = 0; | |
308 | ||
309 | if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < | |
310 | PAGE_CACHE_SIZE) { | |
311 | bio_get(bio); | |
312 | ||
313 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); | |
314 | BUG_ON(ret); | |
315 | ||
316 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); | |
317 | BUG_ON(ret); | |
318 | ||
319 | bio_put(bio); | |
320 | ||
321 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); | |
322 | atomic_inc(&cb->pending_bios); | |
323 | bio->bi_private = cb; | |
324 | bio->bi_end_io = end_compressed_bio_write; | |
325 | bio_add_page(bio, page, PAGE_CACHE_SIZE, 0); | |
326 | } | |
327 | page_index++; | |
328 | bytes_left -= PAGE_CACHE_SIZE; | |
329 | first_byte += PAGE_CACHE_SIZE; | |
330 | } | |
331 | bio_get(bio); | |
332 | ||
333 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); | |
334 | BUG_ON(ret); | |
335 | ||
336 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); | |
337 | BUG_ON(ret); | |
338 | ||
339 | bio_put(bio); | |
340 | return 0; | |
341 | } | |
342 | ||
343 | /* | |
344 | * for a compressed read, the bio we get passed has all the inode pages | |
345 | * in it. We don't actually do IO on those pages but allocate new ones | |
346 | * to hold the compressed pages on disk. | |
347 | * | |
348 | * bio->bi_sector points to the compressed extent on disk | |
349 | * bio->bi_io_vec points to all of the inode pages | |
350 | * bio->bi_vcnt is a count of pages | |
351 | * | |
352 | * After the compressed pages are read, we copy the bytes into the | |
353 | * bio we were passed and then call the bio end_io calls | |
354 | */ | |
355 | int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, | |
356 | int mirror_num, unsigned long bio_flags) | |
357 | { | |
358 | struct extent_io_tree *tree; | |
359 | struct extent_map_tree *em_tree; | |
360 | struct compressed_bio *cb; | |
361 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
362 | unsigned long uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; | |
363 | unsigned long compressed_len; | |
364 | unsigned long nr_pages; | |
365 | unsigned long page_index; | |
366 | struct page *page; | |
367 | struct block_device *bdev; | |
368 | struct bio *comp_bio; | |
369 | u64 cur_disk_byte = (u64)bio->bi_sector << 9; | |
370 | struct extent_map *em; | |
371 | int ret; | |
372 | ||
373 | tree = &BTRFS_I(inode)->io_tree; | |
374 | em_tree = &BTRFS_I(inode)->extent_tree; | |
375 | ||
376 | /* we need the actual starting offset of this extent in the file */ | |
377 | spin_lock(&em_tree->lock); | |
378 | em = lookup_extent_mapping(em_tree, | |
379 | page_offset(bio->bi_io_vec->bv_page), | |
380 | PAGE_CACHE_SIZE); | |
381 | spin_unlock(&em_tree->lock); | |
382 | ||
383 | cb = kmalloc(sizeof(*cb), GFP_NOFS); | |
384 | atomic_set(&cb->pending_bios, 0); | |
385 | cb->errors = 0; | |
386 | cb->inode = inode; | |
387 | ||
388 | cb->start = em->start; | |
389 | compressed_len = em->block_len; | |
390 | free_extent_map(em); | |
391 | ||
392 | cb->len = uncompressed_len; | |
393 | cb->compressed_len = compressed_len; | |
394 | cb->orig_bio = bio; | |
395 | ||
396 | nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) / | |
397 | PAGE_CACHE_SIZE; | |
398 | cb->compressed_pages = kmalloc(sizeof(struct page *) * nr_pages, | |
399 | GFP_NOFS); | |
400 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; | |
401 | ||
402 | for (page_index = 0; page_index < nr_pages; page_index++) { | |
403 | cb->compressed_pages[page_index] = alloc_page(GFP_NOFS | | |
404 | __GFP_HIGHMEM); | |
405 | } | |
406 | cb->nr_pages = nr_pages; | |
407 | ||
408 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS); | |
409 | comp_bio->bi_private = cb; | |
410 | comp_bio->bi_end_io = end_compressed_bio_read; | |
411 | atomic_inc(&cb->pending_bios); | |
412 | ||
413 | for (page_index = 0; page_index < nr_pages; page_index++) { | |
414 | page = cb->compressed_pages[page_index]; | |
415 | page->mapping = inode->i_mapping; | |
416 | if (comp_bio->bi_size) | |
417 | ret = tree->ops->merge_bio_hook(page, 0, | |
418 | PAGE_CACHE_SIZE, | |
419 | comp_bio, 0); | |
420 | else | |
421 | ret = 0; | |
422 | ||
423 | if (ret || bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0) < | |
424 | PAGE_CACHE_SIZE) { | |
425 | bio_get(comp_bio); | |
426 | ||
427 | ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); | |
428 | BUG_ON(ret); | |
429 | ||
430 | ret = btrfs_map_bio(root, READ, comp_bio, 0, 0); | |
431 | BUG_ON(ret); | |
432 | ||
433 | bio_put(comp_bio); | |
434 | ||
435 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, | |
436 | GFP_NOFS); | |
437 | atomic_inc(&cb->pending_bios); | |
438 | bio->bi_private = cb; | |
439 | bio->bi_end_io = end_compressed_bio_write; | |
440 | bio_add_page(bio, page, PAGE_CACHE_SIZE, 0); | |
441 | } | |
442 | cur_disk_byte += PAGE_CACHE_SIZE; | |
443 | } | |
444 | bio_get(comp_bio); | |
445 | ||
446 | ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); | |
447 | BUG_ON(ret); | |
448 | ||
449 | ret = btrfs_map_bio(root, READ, comp_bio, 0, 0); | |
450 | BUG_ON(ret); | |
451 | ||
452 | bio_put(comp_bio); | |
453 | return 0; | |
454 | } |