xref: /linux/fs/nilfs2/segbuf.c (revision 3932b9ca55b0be314a36d3e84faff3e823c081f5)
1 /*
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 <linux/backing-dev.h>
28 #include <linux/slab.h>
29 #include "page.h"
30 #include "segbuf.h"
31 
32 
33 struct nilfs_write_info {
34 	struct the_nilfs       *nilfs;
35 	struct bio	       *bio;
36 	int			start, end; /* The region to be submitted */
37 	int			rest_blocks;
38 	int			max_pages;
39 	int			nr_vecs;
40 	sector_t		blocknr;
41 };
42 
43 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
44 			      struct the_nilfs *nilfs);
45 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf);
46 
47 struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb)
48 {
49 	struct nilfs_segment_buffer *segbuf;
50 
51 	segbuf = kmem_cache_alloc(nilfs_segbuf_cachep, GFP_NOFS);
52 	if (unlikely(!segbuf))
53 		return NULL;
54 
55 	segbuf->sb_super = sb;
56 	INIT_LIST_HEAD(&segbuf->sb_list);
57 	INIT_LIST_HEAD(&segbuf->sb_segsum_buffers);
58 	INIT_LIST_HEAD(&segbuf->sb_payload_buffers);
59 	segbuf->sb_super_root = NULL;
60 
61 	init_completion(&segbuf->sb_bio_event);
62 	atomic_set(&segbuf->sb_err, 0);
63 	segbuf->sb_nbio = 0;
64 
65 	return segbuf;
66 }
67 
68 void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
69 {
70 	kmem_cache_free(nilfs_segbuf_cachep, segbuf);
71 }
72 
73 void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
74 		     unsigned long offset, struct the_nilfs *nilfs)
75 {
76 	segbuf->sb_segnum = segnum;
77 	nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start,
78 				&segbuf->sb_fseg_end);
79 
80 	segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset;
81 	segbuf->sb_rest_blocks =
82 		segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
83 }
84 
85 /**
86  * nilfs_segbuf_map_cont - map a new log behind a given log
87  * @segbuf: new segment buffer
88  * @prev: segment buffer containing a log to be continued
89  */
90 void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
91 			   struct nilfs_segment_buffer *prev)
92 {
93 	segbuf->sb_segnum = prev->sb_segnum;
94 	segbuf->sb_fseg_start = prev->sb_fseg_start;
95 	segbuf->sb_fseg_end = prev->sb_fseg_end;
96 	segbuf->sb_pseg_start = prev->sb_pseg_start + prev->sb_sum.nblocks;
97 	segbuf->sb_rest_blocks =
98 		segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
99 }
100 
101 void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf,
102 				  __u64 nextnum, struct the_nilfs *nilfs)
103 {
104 	segbuf->sb_nextnum = nextnum;
105 	segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum);
106 }
107 
108 int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf)
109 {
110 	struct buffer_head *bh;
111 
112 	bh = sb_getblk(segbuf->sb_super,
113 		       segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk);
114 	if (unlikely(!bh))
115 		return -ENOMEM;
116 
117 	nilfs_segbuf_add_segsum_buffer(segbuf, bh);
118 	return 0;
119 }
120 
121 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
122 				struct buffer_head **bhp)
123 {
124 	struct buffer_head *bh;
125 
126 	bh = sb_getblk(segbuf->sb_super,
127 		       segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
128 	if (unlikely(!bh))
129 		return -ENOMEM;
130 
131 	nilfs_segbuf_add_payload_buffer(segbuf, bh);
132 	*bhp = bh;
133 	return 0;
134 }
135 
136 int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned flags,
137 		       time_t ctime, __u64 cno)
138 {
139 	int err;
140 
141 	segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
142 	err = nilfs_segbuf_extend_segsum(segbuf);
143 	if (unlikely(err))
144 		return err;
145 
146 	segbuf->sb_sum.flags = flags;
147 	segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
148 	segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
149 	segbuf->sb_sum.ctime = ctime;
150 	segbuf->sb_sum.cno = cno;
151 	return 0;
152 }
153 
154 /*
155  * Setup segment summary
156  */
157 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
158 {
159 	struct nilfs_segment_summary *raw_sum;
160 	struct buffer_head *bh_sum;
161 
162 	bh_sum = list_entry(segbuf->sb_segsum_buffers.next,
163 			    struct buffer_head, b_assoc_buffers);
164 	raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data;
165 
166 	raw_sum->ss_magic    = cpu_to_le32(NILFS_SEGSUM_MAGIC);
167 	raw_sum->ss_bytes    = cpu_to_le16(sizeof(*raw_sum));
168 	raw_sum->ss_flags    = cpu_to_le16(segbuf->sb_sum.flags);
169 	raw_sum->ss_seq      = cpu_to_le64(segbuf->sb_sum.seg_seq);
170 	raw_sum->ss_create   = cpu_to_le64(segbuf->sb_sum.ctime);
171 	raw_sum->ss_next     = cpu_to_le64(segbuf->sb_sum.next);
172 	raw_sum->ss_nblocks  = cpu_to_le32(segbuf->sb_sum.nblocks);
173 	raw_sum->ss_nfinfo   = cpu_to_le32(segbuf->sb_sum.nfinfo);
174 	raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
175 	raw_sum->ss_pad      = 0;
176 	raw_sum->ss_cno      = cpu_to_le64(segbuf->sb_sum.cno);
177 }
178 
179 /*
180  * CRC calculation routines
181  */
182 static void
183 nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf, u32 seed)
184 {
185 	struct buffer_head *bh;
186 	struct nilfs_segment_summary *raw_sum;
187 	unsigned long size, bytes = segbuf->sb_sum.sumbytes;
188 	u32 crc;
189 
190 	bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
191 			b_assoc_buffers);
192 
193 	raw_sum = (struct nilfs_segment_summary *)bh->b_data;
194 	size = min_t(unsigned long, bytes, bh->b_size);
195 	crc = crc32_le(seed,
196 		       (unsigned char *)raw_sum +
197 		       sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
198 		       size - (sizeof(raw_sum->ss_datasum) +
199 			       sizeof(raw_sum->ss_sumsum)));
200 
201 	list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
202 				     b_assoc_buffers) {
203 		bytes -= size;
204 		size = min_t(unsigned long, bytes, bh->b_size);
205 		crc = crc32_le(crc, bh->b_data, size);
206 	}
207 	raw_sum->ss_sumsum = cpu_to_le32(crc);
208 }
209 
210 static void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
211 					  u32 seed)
212 {
213 	struct buffer_head *bh;
214 	struct nilfs_segment_summary *raw_sum;
215 	void *kaddr;
216 	u32 crc;
217 
218 	bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
219 			b_assoc_buffers);
220 	raw_sum = (struct nilfs_segment_summary *)bh->b_data;
221 	crc = crc32_le(seed,
222 		       (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
223 		       bh->b_size - sizeof(raw_sum->ss_datasum));
224 
225 	list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
226 				     b_assoc_buffers) {
227 		crc = crc32_le(crc, bh->b_data, bh->b_size);
228 	}
229 	list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
230 		kaddr = kmap_atomic(bh->b_page);
231 		crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
232 		kunmap_atomic(kaddr);
233 	}
234 	raw_sum->ss_datasum = cpu_to_le32(crc);
235 }
236 
237 static void
238 nilfs_segbuf_fill_in_super_root_crc(struct nilfs_segment_buffer *segbuf,
239 				    u32 seed)
240 {
241 	struct nilfs_super_root *raw_sr;
242 	struct the_nilfs *nilfs = segbuf->sb_super->s_fs_info;
243 	unsigned srsize;
244 	u32 crc;
245 
246 	raw_sr = (struct nilfs_super_root *)segbuf->sb_super_root->b_data;
247 	srsize = NILFS_SR_BYTES(nilfs->ns_inode_size);
248 	crc = crc32_le(seed,
249 		       (unsigned char *)raw_sr + sizeof(raw_sr->sr_sum),
250 		       srsize - sizeof(raw_sr->sr_sum));
251 	raw_sr->sr_sum = cpu_to_le32(crc);
252 }
253 
254 static void nilfs_release_buffers(struct list_head *list)
255 {
256 	struct buffer_head *bh, *n;
257 
258 	list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
259 		list_del_init(&bh->b_assoc_buffers);
260 		brelse(bh);
261 	}
262 }
263 
264 static void nilfs_segbuf_clear(struct nilfs_segment_buffer *segbuf)
265 {
266 	nilfs_release_buffers(&segbuf->sb_segsum_buffers);
267 	nilfs_release_buffers(&segbuf->sb_payload_buffers);
268 	segbuf->sb_super_root = NULL;
269 }
270 
271 /*
272  * Iterators for segment buffers
273  */
274 void nilfs_clear_logs(struct list_head *logs)
275 {
276 	struct nilfs_segment_buffer *segbuf;
277 
278 	list_for_each_entry(segbuf, logs, sb_list)
279 		nilfs_segbuf_clear(segbuf);
280 }
281 
282 void nilfs_truncate_logs(struct list_head *logs,
283 			 struct nilfs_segment_buffer *last)
284 {
285 	struct nilfs_segment_buffer *n, *segbuf;
286 
287 	segbuf = list_prepare_entry(last, logs, sb_list);
288 	list_for_each_entry_safe_continue(segbuf, n, logs, sb_list) {
289 		list_del_init(&segbuf->sb_list);
290 		nilfs_segbuf_clear(segbuf);
291 		nilfs_segbuf_free(segbuf);
292 	}
293 }
294 
295 int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs)
296 {
297 	struct nilfs_segment_buffer *segbuf;
298 	int ret = 0;
299 
300 	list_for_each_entry(segbuf, logs, sb_list) {
301 		ret = nilfs_segbuf_write(segbuf, nilfs);
302 		if (ret)
303 			break;
304 	}
305 	return ret;
306 }
307 
308 int nilfs_wait_on_logs(struct list_head *logs)
309 {
310 	struct nilfs_segment_buffer *segbuf;
311 	int err, ret = 0;
312 
313 	list_for_each_entry(segbuf, logs, sb_list) {
314 		err = nilfs_segbuf_wait(segbuf);
315 		if (err && !ret)
316 			ret = err;
317 	}
318 	return ret;
319 }
320 
321 /**
322  * nilfs_add_checksums_on_logs - add checksums on the logs
323  * @logs: list of segment buffers storing target logs
324  * @seed: checksum seed value
325  */
326 void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed)
327 {
328 	struct nilfs_segment_buffer *segbuf;
329 
330 	list_for_each_entry(segbuf, logs, sb_list) {
331 		if (segbuf->sb_super_root)
332 			nilfs_segbuf_fill_in_super_root_crc(segbuf, seed);
333 		nilfs_segbuf_fill_in_segsum_crc(segbuf, seed);
334 		nilfs_segbuf_fill_in_data_crc(segbuf, seed);
335 	}
336 }
337 
338 /*
339  * BIO operations
340  */
341 static void nilfs_end_bio_write(struct bio *bio, int err)
342 {
343 	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
344 	struct nilfs_segment_buffer *segbuf = bio->bi_private;
345 
346 	if (err == -EOPNOTSUPP) {
347 		set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
348 		/* to be detected by nilfs_segbuf_submit_bio() */
349 	}
350 
351 	if (!uptodate)
352 		atomic_inc(&segbuf->sb_err);
353 
354 	bio_put(bio);
355 	complete(&segbuf->sb_bio_event);
356 }
357 
358 static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
359 				   struct nilfs_write_info *wi, int mode)
360 {
361 	struct bio *bio = wi->bio;
362 	int err;
363 
364 	if (segbuf->sb_nbio > 0 &&
365 	    bdi_write_congested(segbuf->sb_super->s_bdi)) {
366 		wait_for_completion(&segbuf->sb_bio_event);
367 		segbuf->sb_nbio--;
368 		if (unlikely(atomic_read(&segbuf->sb_err))) {
369 			bio_put(bio);
370 			err = -EIO;
371 			goto failed;
372 		}
373 	}
374 
375 	bio->bi_end_io = nilfs_end_bio_write;
376 	bio->bi_private = segbuf;
377 	bio_get(bio);
378 	submit_bio(mode, bio);
379 	segbuf->sb_nbio++;
380 	if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
381 		bio_put(bio);
382 		err = -EOPNOTSUPP;
383 		goto failed;
384 	}
385 	bio_put(bio);
386 
387 	wi->bio = NULL;
388 	wi->rest_blocks -= wi->end - wi->start;
389 	wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
390 	wi->start = wi->end;
391 	return 0;
392 
393  failed:
394 	wi->bio = NULL;
395 	return err;
396 }
397 
398 /**
399  * nilfs_alloc_seg_bio - allocate a new bio for writing log
400  * @nilfs: nilfs object
401  * @start: start block number of the bio
402  * @nr_vecs: request size of page vector.
403  *
404  * Return Value: On success, pointer to the struct bio is returned.
405  * On error, NULL is returned.
406  */
407 static struct bio *nilfs_alloc_seg_bio(struct the_nilfs *nilfs, sector_t start,
408 				       int nr_vecs)
409 {
410 	struct bio *bio;
411 
412 	bio = bio_alloc(GFP_NOIO, nr_vecs);
413 	if (bio == NULL) {
414 		while (!bio && (nr_vecs >>= 1))
415 			bio = bio_alloc(GFP_NOIO, nr_vecs);
416 	}
417 	if (likely(bio)) {
418 		bio->bi_bdev = nilfs->ns_bdev;
419 		bio->bi_iter.bi_sector =
420 			start << (nilfs->ns_blocksize_bits - 9);
421 	}
422 	return bio;
423 }
424 
425 static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
426 				       struct nilfs_write_info *wi)
427 {
428 	wi->bio = NULL;
429 	wi->rest_blocks = segbuf->sb_sum.nblocks;
430 	wi->max_pages = bio_get_nr_vecs(wi->nilfs->ns_bdev);
431 	wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
432 	wi->start = wi->end = 0;
433 	wi->blocknr = segbuf->sb_pseg_start;
434 }
435 
436 static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf,
437 				  struct nilfs_write_info *wi,
438 				  struct buffer_head *bh, int mode)
439 {
440 	int len, err;
441 
442 	BUG_ON(wi->nr_vecs <= 0);
443  repeat:
444 	if (!wi->bio) {
445 		wi->bio = nilfs_alloc_seg_bio(wi->nilfs, wi->blocknr + wi->end,
446 					      wi->nr_vecs);
447 		if (unlikely(!wi->bio))
448 			return -ENOMEM;
449 	}
450 
451 	len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));
452 	if (len == bh->b_size) {
453 		wi->end++;
454 		return 0;
455 	}
456 	/* bio is FULL */
457 	err = nilfs_segbuf_submit_bio(segbuf, wi, mode);
458 	/* never submit current bh */
459 	if (likely(!err))
460 		goto repeat;
461 	return err;
462 }
463 
464 /**
465  * nilfs_segbuf_write - submit write requests of a log
466  * @segbuf: buffer storing a log to be written
467  * @nilfs: nilfs object
468  *
469  * Return Value: On Success, 0 is returned. On Error, one of the following
470  * negative error code is returned.
471  *
472  * %-EIO - I/O error
473  *
474  * %-ENOMEM - Insufficient memory available.
475  */
476 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
477 			      struct the_nilfs *nilfs)
478 {
479 	struct nilfs_write_info wi;
480 	struct buffer_head *bh;
481 	int res = 0, rw = WRITE;
482 
483 	wi.nilfs = nilfs;
484 	nilfs_segbuf_prepare_write(segbuf, &wi);
485 
486 	list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
487 		res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, rw);
488 		if (unlikely(res))
489 			goto failed_bio;
490 	}
491 
492 	list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
493 		res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, rw);
494 		if (unlikely(res))
495 			goto failed_bio;
496 	}
497 
498 	if (wi.bio) {
499 		/*
500 		 * Last BIO is always sent through the following
501 		 * submission.
502 		 */
503 		rw |= REQ_SYNC;
504 		res = nilfs_segbuf_submit_bio(segbuf, &wi, rw);
505 	}
506 
507  failed_bio:
508 	return res;
509 }
510 
511 /**
512  * nilfs_segbuf_wait - wait for completion of requested BIOs
513  * @segbuf: segment buffer
514  *
515  * Return Value: On Success, 0 is returned. On Error, one of the following
516  * negative error code is returned.
517  *
518  * %-EIO - I/O error
519  */
520 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf)
521 {
522 	int err = 0;
523 
524 	if (!segbuf->sb_nbio)
525 		return 0;
526 
527 	do {
528 		wait_for_completion(&segbuf->sb_bio_event);
529 	} while (--segbuf->sb_nbio > 0);
530 
531 	if (unlikely(atomic_read(&segbuf->sb_err) > 0)) {
532 		printk(KERN_ERR "NILFS: IO error writing segment\n");
533 		err = -EIO;
534 	}
535 	return err;
536 }
537