1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * NILFS segment buffer
4  *
5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6  *
7  * Written by Ryusuke Konishi.
8  *
9  */
10 
11 #include <linux/buffer_head.h>
12 #include <linux/writeback.h>
13 #include <linux/crc32.h>
14 #include <linux/backing-dev.h>
15 #include <linux/slab.h>
16 #include "page.h"
17 #include "segbuf.h"
18 
19 
20 struct nilfs_write_info {
21 	struct the_nilfs       *nilfs;
22 	struct bio	       *bio;
23 	int			start, end; /* The region to be submitted */
24 	int			rest_blocks;
25 	int			max_pages;
26 	int			nr_vecs;
27 	sector_t		blocknr;
28 };
29 
30 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
31 			      struct the_nilfs *nilfs);
32 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf);
33 
nilfs_segbuf_new(struct super_block * sb)34 struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb)
35 {
36 	struct nilfs_segment_buffer *segbuf;
37 
38 	segbuf = kmem_cache_alloc(nilfs_segbuf_cachep, GFP_NOFS);
39 	if (unlikely(!segbuf))
40 		return NULL;
41 
42 	segbuf->sb_super = sb;
43 	INIT_LIST_HEAD(&segbuf->sb_list);
44 	INIT_LIST_HEAD(&segbuf->sb_segsum_buffers);
45 	INIT_LIST_HEAD(&segbuf->sb_payload_buffers);
46 	segbuf->sb_super_root = NULL;
47 
48 	init_completion(&segbuf->sb_bio_event);
49 	atomic_set(&segbuf->sb_err, 0);
50 	segbuf->sb_nbio = 0;
51 
52 	return segbuf;
53 }
54 
nilfs_segbuf_free(struct nilfs_segment_buffer * segbuf)55 void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
56 {
57 	kmem_cache_free(nilfs_segbuf_cachep, segbuf);
58 }
59 
nilfs_segbuf_map(struct nilfs_segment_buffer * segbuf,__u64 segnum,unsigned long offset,struct the_nilfs * nilfs)60 void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
61 		     unsigned long offset, struct the_nilfs *nilfs)
62 {
63 	segbuf->sb_segnum = segnum;
64 	nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start,
65 				&segbuf->sb_fseg_end);
66 
67 	segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset;
68 	segbuf->sb_rest_blocks =
69 		segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
70 }
71 
72 /**
73  * nilfs_segbuf_map_cont - map a new log behind a given log
74  * @segbuf: new segment buffer
75  * @prev: segment buffer containing a log to be continued
76  */
nilfs_segbuf_map_cont(struct nilfs_segment_buffer * segbuf,struct nilfs_segment_buffer * prev)77 void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
78 			   struct nilfs_segment_buffer *prev)
79 {
80 	segbuf->sb_segnum = prev->sb_segnum;
81 	segbuf->sb_fseg_start = prev->sb_fseg_start;
82 	segbuf->sb_fseg_end = prev->sb_fseg_end;
83 	segbuf->sb_pseg_start = prev->sb_pseg_start + prev->sb_sum.nblocks;
84 	segbuf->sb_rest_blocks =
85 		segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
86 }
87 
nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer * segbuf,__u64 nextnum,struct the_nilfs * nilfs)88 void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf,
89 				  __u64 nextnum, struct the_nilfs *nilfs)
90 {
91 	segbuf->sb_nextnum = nextnum;
92 	segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum);
93 }
94 
nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer * segbuf)95 int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf)
96 {
97 	struct buffer_head *bh;
98 
99 	bh = sb_getblk(segbuf->sb_super,
100 		       segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk);
101 	if (unlikely(!bh))
102 		return -ENOMEM;
103 
104 	nilfs_segbuf_add_segsum_buffer(segbuf, bh);
105 	return 0;
106 }
107 
nilfs_segbuf_extend_payload(struct nilfs_segment_buffer * segbuf,struct buffer_head ** bhp)108 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
109 				struct buffer_head **bhp)
110 {
111 	struct buffer_head *bh;
112 
113 	bh = sb_getblk(segbuf->sb_super,
114 		       segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
115 	if (unlikely(!bh))
116 		return -ENOMEM;
117 
118 	nilfs_segbuf_add_payload_buffer(segbuf, bh);
119 	*bhp = bh;
120 	return 0;
121 }
122 
nilfs_segbuf_reset(struct nilfs_segment_buffer * segbuf,unsigned int flags,time64_t ctime,__u64 cno)123 int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned int flags,
124 		       time64_t ctime, __u64 cno)
125 {
126 	int err;
127 
128 	segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
129 	err = nilfs_segbuf_extend_segsum(segbuf);
130 	if (unlikely(err))
131 		return err;
132 
133 	segbuf->sb_sum.flags = flags;
134 	segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
135 	segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
136 	segbuf->sb_sum.ctime = ctime;
137 	segbuf->sb_sum.cno = cno;
138 	return 0;
139 }
140 
141 /*
142  * Setup segment summary
143  */
nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer * segbuf)144 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
145 {
146 	struct nilfs_segment_summary *raw_sum;
147 	struct buffer_head *bh_sum;
148 
149 	bh_sum = list_entry(segbuf->sb_segsum_buffers.next,
150 			    struct buffer_head, b_assoc_buffers);
151 	raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data;
152 
153 	raw_sum->ss_magic    = cpu_to_le32(NILFS_SEGSUM_MAGIC);
154 	raw_sum->ss_bytes    = cpu_to_le16(sizeof(*raw_sum));
155 	raw_sum->ss_flags    = cpu_to_le16(segbuf->sb_sum.flags);
156 	raw_sum->ss_seq      = cpu_to_le64(segbuf->sb_sum.seg_seq);
157 	raw_sum->ss_create   = cpu_to_le64(segbuf->sb_sum.ctime);
158 	raw_sum->ss_next     = cpu_to_le64(segbuf->sb_sum.next);
159 	raw_sum->ss_nblocks  = cpu_to_le32(segbuf->sb_sum.nblocks);
160 	raw_sum->ss_nfinfo   = cpu_to_le32(segbuf->sb_sum.nfinfo);
161 	raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
162 	raw_sum->ss_pad      = 0;
163 	raw_sum->ss_cno      = cpu_to_le64(segbuf->sb_sum.cno);
164 }
165 
166 /*
167  * CRC calculation routines
168  */
169 static void
nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer * segbuf,u32 seed)170 nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf, u32 seed)
171 {
172 	struct buffer_head *bh;
173 	struct nilfs_segment_summary *raw_sum;
174 	unsigned long size, bytes = segbuf->sb_sum.sumbytes;
175 	u32 crc;
176 
177 	bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
178 			b_assoc_buffers);
179 
180 	raw_sum = (struct nilfs_segment_summary *)bh->b_data;
181 	size = min_t(unsigned long, bytes, bh->b_size);
182 	crc = crc32_le(seed,
183 		       (unsigned char *)raw_sum +
184 		       sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
185 		       size - (sizeof(raw_sum->ss_datasum) +
186 			       sizeof(raw_sum->ss_sumsum)));
187 
188 	list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
189 				     b_assoc_buffers) {
190 		bytes -= size;
191 		size = min_t(unsigned long, bytes, bh->b_size);
192 		crc = crc32_le(crc, bh->b_data, size);
193 	}
194 	raw_sum->ss_sumsum = cpu_to_le32(crc);
195 }
196 
nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer * segbuf,u32 seed)197 static void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
198 					  u32 seed)
199 {
200 	struct buffer_head *bh;
201 	struct nilfs_segment_summary *raw_sum;
202 	void *kaddr;
203 	u32 crc;
204 
205 	bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
206 			b_assoc_buffers);
207 	raw_sum = (struct nilfs_segment_summary *)bh->b_data;
208 	crc = crc32_le(seed,
209 		       (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
210 		       bh->b_size - sizeof(raw_sum->ss_datasum));
211 
212 	list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
213 				     b_assoc_buffers) {
214 		crc = crc32_le(crc, bh->b_data, bh->b_size);
215 	}
216 	list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
217 		kaddr = kmap_atomic(bh->b_page);
218 		crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
219 		kunmap_atomic(kaddr);
220 	}
221 	raw_sum->ss_datasum = cpu_to_le32(crc);
222 }
223 
224 static void
nilfs_segbuf_fill_in_super_root_crc(struct nilfs_segment_buffer * segbuf,u32 seed)225 nilfs_segbuf_fill_in_super_root_crc(struct nilfs_segment_buffer *segbuf,
226 				    u32 seed)
227 {
228 	struct nilfs_super_root *raw_sr;
229 	struct the_nilfs *nilfs = segbuf->sb_super->s_fs_info;
230 	unsigned int srsize;
231 	u32 crc;
232 
233 	raw_sr = (struct nilfs_super_root *)segbuf->sb_super_root->b_data;
234 	srsize = NILFS_SR_BYTES(nilfs->ns_inode_size);
235 	crc = crc32_le(seed,
236 		       (unsigned char *)raw_sr + sizeof(raw_sr->sr_sum),
237 		       srsize - sizeof(raw_sr->sr_sum));
238 	raw_sr->sr_sum = cpu_to_le32(crc);
239 }
240 
nilfs_release_buffers(struct list_head * list)241 static void nilfs_release_buffers(struct list_head *list)
242 {
243 	struct buffer_head *bh, *n;
244 
245 	list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
246 		list_del_init(&bh->b_assoc_buffers);
247 		brelse(bh);
248 	}
249 }
250 
nilfs_segbuf_clear(struct nilfs_segment_buffer * segbuf)251 static void nilfs_segbuf_clear(struct nilfs_segment_buffer *segbuf)
252 {
253 	nilfs_release_buffers(&segbuf->sb_segsum_buffers);
254 	nilfs_release_buffers(&segbuf->sb_payload_buffers);
255 	segbuf->sb_super_root = NULL;
256 }
257 
258 /*
259  * Iterators for segment buffers
260  */
nilfs_clear_logs(struct list_head * logs)261 void nilfs_clear_logs(struct list_head *logs)
262 {
263 	struct nilfs_segment_buffer *segbuf;
264 
265 	list_for_each_entry(segbuf, logs, sb_list)
266 		nilfs_segbuf_clear(segbuf);
267 }
268 
nilfs_truncate_logs(struct list_head * logs,struct nilfs_segment_buffer * last)269 void nilfs_truncate_logs(struct list_head *logs,
270 			 struct nilfs_segment_buffer *last)
271 {
272 	struct nilfs_segment_buffer *n, *segbuf;
273 
274 	segbuf = list_prepare_entry(last, logs, sb_list);
275 	list_for_each_entry_safe_continue(segbuf, n, logs, sb_list) {
276 		list_del_init(&segbuf->sb_list);
277 		nilfs_segbuf_clear(segbuf);
278 		nilfs_segbuf_free(segbuf);
279 	}
280 }
281 
nilfs_write_logs(struct list_head * logs,struct the_nilfs * nilfs)282 int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs)
283 {
284 	struct nilfs_segment_buffer *segbuf;
285 	int ret = 0;
286 
287 	list_for_each_entry(segbuf, logs, sb_list) {
288 		ret = nilfs_segbuf_write(segbuf, nilfs);
289 		if (ret)
290 			break;
291 	}
292 	return ret;
293 }
294 
nilfs_wait_on_logs(struct list_head * logs)295 int nilfs_wait_on_logs(struct list_head *logs)
296 {
297 	struct nilfs_segment_buffer *segbuf;
298 	int err, ret = 0;
299 
300 	list_for_each_entry(segbuf, logs, sb_list) {
301 		err = nilfs_segbuf_wait(segbuf);
302 		if (err && !ret)
303 			ret = err;
304 	}
305 	return ret;
306 }
307 
308 /**
309  * nilfs_add_checksums_on_logs - add checksums on the logs
310  * @logs: list of segment buffers storing target logs
311  * @seed: checksum seed value
312  */
nilfs_add_checksums_on_logs(struct list_head * logs,u32 seed)313 void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed)
314 {
315 	struct nilfs_segment_buffer *segbuf;
316 
317 	list_for_each_entry(segbuf, logs, sb_list) {
318 		if (segbuf->sb_super_root)
319 			nilfs_segbuf_fill_in_super_root_crc(segbuf, seed);
320 		nilfs_segbuf_fill_in_segsum_crc(segbuf, seed);
321 		nilfs_segbuf_fill_in_data_crc(segbuf, seed);
322 	}
323 }
324 
325 /*
326  * BIO operations
327  */
nilfs_end_bio_write(struct bio * bio)328 static void nilfs_end_bio_write(struct bio *bio)
329 {
330 	struct nilfs_segment_buffer *segbuf = bio->bi_private;
331 
332 	if (bio->bi_status)
333 		atomic_inc(&segbuf->sb_err);
334 
335 	bio_put(bio);
336 	complete(&segbuf->sb_bio_event);
337 }
338 
nilfs_segbuf_submit_bio(struct nilfs_segment_buffer * segbuf,struct nilfs_write_info * wi)339 static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
340 				   struct nilfs_write_info *wi)
341 {
342 	struct bio *bio = wi->bio;
343 
344 	bio->bi_end_io = nilfs_end_bio_write;
345 	bio->bi_private = segbuf;
346 	submit_bio(bio);
347 	segbuf->sb_nbio++;
348 
349 	wi->bio = NULL;
350 	wi->rest_blocks -= wi->end - wi->start;
351 	wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
352 	wi->start = wi->end;
353 	return 0;
354 }
355 
nilfs_segbuf_prepare_write(struct nilfs_segment_buffer * segbuf,struct nilfs_write_info * wi)356 static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
357 				       struct nilfs_write_info *wi)
358 {
359 	wi->bio = NULL;
360 	wi->rest_blocks = segbuf->sb_sum.nblocks;
361 	wi->max_pages = BIO_MAX_VECS;
362 	wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
363 	wi->start = wi->end = 0;
364 	wi->blocknr = segbuf->sb_pseg_start;
365 }
366 
nilfs_segbuf_submit_bh(struct nilfs_segment_buffer * segbuf,struct nilfs_write_info * wi,struct buffer_head * bh)367 static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf,
368 				  struct nilfs_write_info *wi,
369 				  struct buffer_head *bh)
370 {
371 	int len, err;
372 
373 	BUG_ON(wi->nr_vecs <= 0);
374  repeat:
375 	if (!wi->bio) {
376 		wi->bio = bio_alloc(wi->nilfs->ns_bdev, wi->nr_vecs,
377 				    REQ_OP_WRITE, GFP_NOIO);
378 		wi->bio->bi_iter.bi_sector = (wi->blocknr + wi->end) <<
379 			(wi->nilfs->ns_blocksize_bits - 9);
380 	}
381 
382 	len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));
383 	if (len == bh->b_size) {
384 		wi->end++;
385 		return 0;
386 	}
387 	/* bio is FULL */
388 	err = nilfs_segbuf_submit_bio(segbuf, wi);
389 	/* never submit current bh */
390 	if (likely(!err))
391 		goto repeat;
392 	return err;
393 }
394 
395 /**
396  * nilfs_segbuf_write - submit write requests of a log
397  * @segbuf: buffer storing a log to be written
398  * @nilfs: nilfs object
399  *
400  * Return Value: On Success, 0 is returned. On Error, one of the following
401  * negative error code is returned.
402  *
403  * %-EIO - I/O error
404  *
405  * %-ENOMEM - Insufficient memory available.
406  */
nilfs_segbuf_write(struct nilfs_segment_buffer * segbuf,struct the_nilfs * nilfs)407 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
408 			      struct the_nilfs *nilfs)
409 {
410 	struct nilfs_write_info wi;
411 	struct buffer_head *bh;
412 	int res = 0;
413 
414 	wi.nilfs = nilfs;
415 	nilfs_segbuf_prepare_write(segbuf, &wi);
416 
417 	list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
418 		res = nilfs_segbuf_submit_bh(segbuf, &wi, bh);
419 		if (unlikely(res))
420 			goto failed_bio;
421 	}
422 
423 	list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
424 		res = nilfs_segbuf_submit_bh(segbuf, &wi, bh);
425 		if (unlikely(res))
426 			goto failed_bio;
427 	}
428 
429 	if (wi.bio) {
430 		/*
431 		 * Last BIO is always sent through the following
432 		 * submission.
433 		 */
434 		wi.bio->bi_opf |= REQ_SYNC;
435 		res = nilfs_segbuf_submit_bio(segbuf, &wi);
436 	}
437 
438  failed_bio:
439 	return res;
440 }
441 
442 /**
443  * nilfs_segbuf_wait - wait for completion of requested BIOs
444  * @segbuf: segment buffer
445  *
446  * Return Value: On Success, 0 is returned. On Error, one of the following
447  * negative error code is returned.
448  *
449  * %-EIO - I/O error
450  */
nilfs_segbuf_wait(struct nilfs_segment_buffer * segbuf)451 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf)
452 {
453 	int err = 0;
454 
455 	if (!segbuf->sb_nbio)
456 		return 0;
457 
458 	do {
459 		wait_for_completion(&segbuf->sb_bio_event);
460 	} while (--segbuf->sb_nbio > 0);
461 
462 	if (unlikely(atomic_read(&segbuf->sb_err) > 0)) {
463 		nilfs_err(segbuf->sb_super,
464 			  "I/O error writing log (start-blocknr=%llu, block-count=%lu) in segment %llu",
465 			  (unsigned long long)segbuf->sb_pseg_start,
466 			  segbuf->sb_sum.nblocks,
467 			  (unsigned long long)segbuf->sb_segnum);
468 		err = -EIO;
469 	}
470 	return err;
471 }
472