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Ryusuke Konishi64b5a322009-04-06 19:01:36 -07001/*
2 * segbuf.c - NILFS segment buffer
3 *
4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 *
20 * Written by Ryusuke Konishi <ryusuke@osrg.net>
21 *
22 */
23
24#include <linux/buffer_head.h>
25#include <linux/writeback.h>
26#include <linux/crc32.h>
27#include "page.h"
28#include "segbuf.h"
Ryusuke Konishi64b5a322009-04-06 19:01:36 -070029
30
31static struct kmem_cache *nilfs_segbuf_cachep;
32
33static void nilfs_segbuf_init_once(void *obj)
34{
35 memset(obj, 0, sizeof(struct nilfs_segment_buffer));
36}
37
38int __init nilfs_init_segbuf_cache(void)
39{
40 nilfs_segbuf_cachep =
41 kmem_cache_create("nilfs2_segbuf_cache",
42 sizeof(struct nilfs_segment_buffer),
43 0, SLAB_RECLAIM_ACCOUNT,
44 nilfs_segbuf_init_once);
45
46 return (nilfs_segbuf_cachep == NULL) ? -ENOMEM : 0;
47}
48
49void nilfs_destroy_segbuf_cache(void)
50{
51 kmem_cache_destroy(nilfs_segbuf_cachep);
52}
53
54struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb)
55{
56 struct nilfs_segment_buffer *segbuf;
57
58 segbuf = kmem_cache_alloc(nilfs_segbuf_cachep, GFP_NOFS);
59 if (unlikely(!segbuf))
60 return NULL;
61
62 segbuf->sb_super = sb;
63 INIT_LIST_HEAD(&segbuf->sb_list);
64 INIT_LIST_HEAD(&segbuf->sb_segsum_buffers);
65 INIT_LIST_HEAD(&segbuf->sb_payload_buffers);
Ryusuke Konishi64b5a322009-04-06 19:01:36 -070066 return segbuf;
67}
68
69void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
70{
Ryusuke Konishi64b5a322009-04-06 19:01:36 -070071 kmem_cache_free(nilfs_segbuf_cachep, segbuf);
72}
73
Ryusuke Konishicece5522009-04-06 19:01:58 -070074void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
Ryusuke Konishi64b5a322009-04-06 19:01:36 -070075 unsigned long offset, struct the_nilfs *nilfs)
76{
Ryusuke Konishi64b5a322009-04-06 19:01:36 -070077 segbuf->sb_segnum = segnum;
78 nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start,
79 &segbuf->sb_fseg_end);
80
81 segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset;
82 segbuf->sb_rest_blocks =
83 segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
Ryusuke Konishi64b5a322009-04-06 19:01:36 -070084}
85
86void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf,
87 __u64 nextnum, struct the_nilfs *nilfs)
88{
89 segbuf->sb_nextnum = nextnum;
90 segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum);
91}
92
93int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf)
94{
95 struct buffer_head *bh;
96
97 bh = sb_getblk(segbuf->sb_super,
98 segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk);
99 if (unlikely(!bh))
100 return -ENOMEM;
101
102 nilfs_segbuf_add_segsum_buffer(segbuf, bh);
103 return 0;
104}
105
106int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
107 struct buffer_head **bhp)
108{
109 struct buffer_head *bh;
110
111 bh = sb_getblk(segbuf->sb_super,
112 segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
113 if (unlikely(!bh))
114 return -ENOMEM;
115
116 nilfs_segbuf_add_payload_buffer(segbuf, bh);
117 *bhp = bh;
118 return 0;
119}
120
121int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned flags,
122 time_t ctime)
123{
124 int err;
125
126 segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
127 err = nilfs_segbuf_extend_segsum(segbuf);
128 if (unlikely(err))
129 return err;
130
131 segbuf->sb_sum.flags = flags;
132 segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
133 segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
134 segbuf->sb_sum.ctime = ctime;
135
136 segbuf->sb_io_error = 0;
137 return 0;
138}
139
140/*
141 * Setup segument summary
142 */
143void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
144{
145 struct nilfs_segment_summary *raw_sum;
146 struct buffer_head *bh_sum;
147
148 bh_sum = list_entry(segbuf->sb_segsum_buffers.next,
149 struct buffer_head, b_assoc_buffers);
150 raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data;
151
152 raw_sum->ss_magic = cpu_to_le32(NILFS_SEGSUM_MAGIC);
153 raw_sum->ss_bytes = cpu_to_le16(sizeof(*raw_sum));
154 raw_sum->ss_flags = cpu_to_le16(segbuf->sb_sum.flags);
155 raw_sum->ss_seq = cpu_to_le64(segbuf->sb_sum.seg_seq);
156 raw_sum->ss_create = cpu_to_le64(segbuf->sb_sum.ctime);
157 raw_sum->ss_next = cpu_to_le64(segbuf->sb_sum.next);
158 raw_sum->ss_nblocks = cpu_to_le32(segbuf->sb_sum.nblocks);
159 raw_sum->ss_nfinfo = cpu_to_le32(segbuf->sb_sum.nfinfo);
160 raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
161 raw_sum->ss_pad = 0;
162}
163
164/*
165 * CRC calculation routines
166 */
167void nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf,
168 u32 seed)
169{
170 struct buffer_head *bh;
171 struct nilfs_segment_summary *raw_sum;
172 unsigned long size, bytes = segbuf->sb_sum.sumbytes;
173 u32 crc;
174
175 bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
176 b_assoc_buffers);
177
178 raw_sum = (struct nilfs_segment_summary *)bh->b_data;
179 size = min_t(unsigned long, bytes, bh->b_size);
180 crc = crc32_le(seed,
181 (unsigned char *)raw_sum +
182 sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
183 size - (sizeof(raw_sum->ss_datasum) +
184 sizeof(raw_sum->ss_sumsum)));
185
186 list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
187 b_assoc_buffers) {
188 bytes -= size;
189 size = min_t(unsigned long, bytes, bh->b_size);
190 crc = crc32_le(crc, bh->b_data, size);
191 }
192 raw_sum->ss_sumsum = cpu_to_le32(crc);
193}
194
195void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
196 u32 seed)
197{
198 struct buffer_head *bh;
199 struct nilfs_segment_summary *raw_sum;
200 void *kaddr;
201 u32 crc;
202
203 bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
204 b_assoc_buffers);
205 raw_sum = (struct nilfs_segment_summary *)bh->b_data;
206 crc = crc32_le(seed,
207 (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
208 bh->b_size - sizeof(raw_sum->ss_datasum));
209
210 list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
211 b_assoc_buffers) {
212 crc = crc32_le(crc, bh->b_data, bh->b_size);
213 }
214 list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
215 kaddr = kmap_atomic(bh->b_page, KM_USER0);
216 crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
217 kunmap_atomic(kaddr, KM_USER0);
218 }
219 raw_sum->ss_datasum = cpu_to_le32(crc);
220}
221
222void nilfs_release_buffers(struct list_head *list)
223{
224 struct buffer_head *bh, *n;
225
226 list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
227 list_del_init(&bh->b_assoc_buffers);
228 if (buffer_nilfs_allocated(bh)) {
229 struct page *clone_page = bh->b_page;
230
231 /* remove clone page */
232 brelse(bh);
233 page_cache_release(clone_page); /* for each bh */
234 if (page_count(clone_page) <= 2) {
235 lock_page(clone_page);
236 nilfs_free_private_page(clone_page);
237 }
238 continue;
239 }
240 brelse(bh);
241 }
242}
243
244/*
245 * BIO operations
246 */
247static void nilfs_end_bio_write(struct bio *bio, int err)
248{
249 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
250 struct nilfs_write_info *wi = bio->bi_private;
251
252 if (err == -EOPNOTSUPP) {
253 set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
254 bio_put(bio);
255 /* to be detected by submit_seg_bio() */
256 }
257
258 if (!uptodate)
259 atomic_inc(&wi->err);
260
261 bio_put(bio);
262 complete(&wi->bio_event);
263}
264
265static int nilfs_submit_seg_bio(struct nilfs_write_info *wi, int mode)
266{
267 struct bio *bio = wi->bio;
268 int err;
269
270 if (wi->nbio > 0 && bdi_write_congested(wi->bdi)) {
271 wait_for_completion(&wi->bio_event);
272 wi->nbio--;
273 if (unlikely(atomic_read(&wi->err))) {
274 bio_put(bio);
275 err = -EIO;
276 goto failed;
277 }
278 }
279
280 bio->bi_end_io = nilfs_end_bio_write;
281 bio->bi_private = wi;
282 bio_get(bio);
283 submit_bio(mode, bio);
284 if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
285 bio_put(bio);
286 err = -EOPNOTSUPP;
287 goto failed;
288 }
289 wi->nbio++;
290 bio_put(bio);
291
292 wi->bio = NULL;
293 wi->rest_blocks -= wi->end - wi->start;
294 wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
295 wi->start = wi->end;
296 return 0;
297
298 failed:
299 wi->bio = NULL;
300 return err;
301}
302
303/**
304 * nilfs_alloc_seg_bio - allocate a bio for writing segment.
305 * @sb: super block
306 * @start: beginning disk block number of this BIO.
307 * @nr_vecs: request size of page vector.
308 *
309 * alloc_seg_bio() allocates a new BIO structure and initialize it.
310 *
311 * Return Value: On success, pointer to the struct bio is returned.
312 * On error, NULL is returned.
313 */
314static struct bio *nilfs_alloc_seg_bio(struct super_block *sb, sector_t start,
315 int nr_vecs)
316{
317 struct bio *bio;
318
Ryusuke Konishic1b353f2009-06-19 15:25:42 +0900319 bio = bio_alloc(GFP_NOIO, nr_vecs);
Ryusuke Konishi64b5a322009-04-06 19:01:36 -0700320 if (bio == NULL) {
321 while (!bio && (nr_vecs >>= 1))
Ryusuke Konishic1b353f2009-06-19 15:25:42 +0900322 bio = bio_alloc(GFP_NOIO, nr_vecs);
Ryusuke Konishi64b5a322009-04-06 19:01:36 -0700323 }
324 if (likely(bio)) {
325 bio->bi_bdev = sb->s_bdev;
326 bio->bi_sector = (sector_t)start << (sb->s_blocksize_bits - 9);
327 }
328 return bio;
329}
330
331void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
332 struct nilfs_write_info *wi)
333{
334 wi->bio = NULL;
335 wi->rest_blocks = segbuf->sb_sum.nblocks;
336 wi->max_pages = bio_get_nr_vecs(wi->sb->s_bdev);
337 wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
338 wi->start = wi->end = 0;
339 wi->nbio = 0;
340 wi->blocknr = segbuf->sb_pseg_start;
341
342 atomic_set(&wi->err, 0);
343 init_completion(&wi->bio_event);
344}
345
346static int nilfs_submit_bh(struct nilfs_write_info *wi, struct buffer_head *bh,
347 int mode)
348{
349 int len, err;
350
351 BUG_ON(wi->nr_vecs <= 0);
352 repeat:
353 if (!wi->bio) {
354 wi->bio = nilfs_alloc_seg_bio(wi->sb, wi->blocknr + wi->end,
355 wi->nr_vecs);
356 if (unlikely(!wi->bio))
357 return -ENOMEM;
358 }
359
360 len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));
361 if (len == bh->b_size) {
362 wi->end++;
363 return 0;
364 }
365 /* bio is FULL */
366 err = nilfs_submit_seg_bio(wi, mode);
367 /* never submit current bh */
368 if (likely(!err))
369 goto repeat;
370 return err;
371}
372
373int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
374 struct nilfs_write_info *wi)
375{
376 struct buffer_head *bh;
377 int res, rw = WRITE;
378
379 list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
380 res = nilfs_submit_bh(wi, bh, rw);
381 if (unlikely(res))
382 goto failed_bio;
383 }
384
385 list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
386 res = nilfs_submit_bh(wi, bh, rw);
387 if (unlikely(res))
388 goto failed_bio;
389 }
390
391 if (wi->bio) {
392 /*
393 * Last BIO is always sent through the following
394 * submission.
395 */
Ryusuke Konishi30bda0b2009-05-17 10:57:43 +0900396 rw |= (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
Ryusuke Konishi64b5a322009-04-06 19:01:36 -0700397 res = nilfs_submit_seg_bio(wi, rw);
398 if (unlikely(res))
399 goto failed_bio;
400 }
401
402 res = 0;
403 out:
404 return res;
405
406 failed_bio:
407 atomic_inc(&wi->err);
408 goto out;
409}
410
411/**
412 * nilfs_segbuf_wait - wait for completion of requested BIOs
413 * @wi: nilfs_write_info
414 *
415 * Return Value: On Success, 0 is returned. On Error, one of the following
416 * negative error code is returned.
417 *
418 * %-EIO - I/O error
419 */
420int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf,
421 struct nilfs_write_info *wi)
422{
423 int err = 0;
424
425 if (!wi->nbio)
426 return 0;
427
428 do {
429 wait_for_completion(&wi->bio_event);
430 } while (--wi->nbio > 0);
431
432 if (unlikely(atomic_read(&wi->err) > 0)) {
433 printk(KERN_ERR "NILFS: IO error writing segment\n");
434 err = -EIO;
435 segbuf->sb_io_error = 1;
436 }
437 return err;
438}