segbuf.c

  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
 20struct 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
 30static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
 31			      struct the_nilfs *nilfs);
 32static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf);
 33
 34struct 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
 55void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
 56{
 57	kmem_cache_free(nilfs_segbuf_cachep, segbuf);
 58}
 59
 60void 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 */
 77void 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
 88void 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
 95int 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	lock_buffer(bh);
105	if (!buffer_uptodate(bh)) {
106		memset(bh->b_data, 0, bh->b_size);
107		set_buffer_uptodate(bh);
108	}
109	unlock_buffer(bh);
110	nilfs_segbuf_add_segsum_buffer(segbuf, bh);
111	return 0;
112}
113
114int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
115				struct buffer_head **bhp)
116{
117	struct buffer_head *bh;
118
119	bh = sb_getblk(segbuf->sb_super,
120		       segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
121	if (unlikely(!bh))
122		return -ENOMEM;
123
124	nilfs_segbuf_add_payload_buffer(segbuf, bh);
125	*bhp = bh;
126	return 0;
127}
128
129int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned int flags,
130		       time64_t ctime, __u64 cno)
131{
132	int err;
133
134	segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
135	err = nilfs_segbuf_extend_segsum(segbuf);
136	if (unlikely(err))
137		return err;
138
139	segbuf->sb_sum.flags = flags;
140	segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
141	segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
142	segbuf->sb_sum.ctime = ctime;
143	segbuf->sb_sum.cno = cno;
144	return 0;
145}
146
147/*
148 * Setup segment summary
149 */
150void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
151{
152	struct nilfs_segment_summary *raw_sum;
153	struct buffer_head *bh_sum;
154
155	bh_sum = list_entry(segbuf->sb_segsum_buffers.next,
156			    struct buffer_head, b_assoc_buffers);
157	raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data;
158
159	raw_sum->ss_magic    = cpu_to_le32(NILFS_SEGSUM_MAGIC);
160	raw_sum->ss_bytes    = cpu_to_le16(sizeof(*raw_sum));
161	raw_sum->ss_flags    = cpu_to_le16(segbuf->sb_sum.flags);
162	raw_sum->ss_seq      = cpu_to_le64(segbuf->sb_sum.seg_seq);
163	raw_sum->ss_create   = cpu_to_le64(segbuf->sb_sum.ctime);
164	raw_sum->ss_next     = cpu_to_le64(segbuf->sb_sum.next);
165	raw_sum->ss_nblocks  = cpu_to_le32(segbuf->sb_sum.nblocks);
166	raw_sum->ss_nfinfo   = cpu_to_le32(segbuf->sb_sum.nfinfo);
167	raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
168	raw_sum->ss_pad      = 0;
169	raw_sum->ss_cno      = cpu_to_le64(segbuf->sb_sum.cno);
170}
171
172/*
173 * CRC calculation routines
174 */
175static void
176nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf, u32 seed)
177{
178	struct buffer_head *bh;
179	struct nilfs_segment_summary *raw_sum;
180	unsigned long size, bytes = segbuf->sb_sum.sumbytes;
181	u32 crc;
182
183	bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
184			b_assoc_buffers);
185
186	raw_sum = (struct nilfs_segment_summary *)bh->b_data;
187	size = min_t(unsigned long, bytes, bh->b_size);
188	crc = crc32_le(seed,
189		       (unsigned char *)raw_sum +
190		       sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
191		       size - (sizeof(raw_sum->ss_datasum) +
192			       sizeof(raw_sum->ss_sumsum)));
193
194	list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
195				     b_assoc_buffers) {
196		bytes -= size;
197		size = min_t(unsigned long, bytes, bh->b_size);
198		crc = crc32_le(crc, bh->b_data, size);
199	}
200	raw_sum->ss_sumsum = cpu_to_le32(crc);
201}
202
203static void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
204					  u32 seed)
205{
206	struct buffer_head *bh;
207	struct nilfs_segment_summary *raw_sum;
208	u32 crc;
209
210	bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
211			b_assoc_buffers);
212	raw_sum = (struct nilfs_segment_summary *)bh->b_data;
213	crc = crc32_le(seed,
214		       (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
215		       bh->b_size - sizeof(raw_sum->ss_datasum));
216
217	list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
218				     b_assoc_buffers) {
219		crc = crc32_le(crc, bh->b_data, bh->b_size);
220	}
221	list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
222		size_t offset = offset_in_folio(bh->b_folio, bh->b_data);
223		unsigned char *from;
224
225		/* Do not support block sizes larger than PAGE_SIZE */
226		from = kmap_local_folio(bh->b_folio, offset);
227		crc = crc32_le(crc, from, bh->b_size);
228		kunmap_local(from);
229	}
230	raw_sum->ss_datasum = cpu_to_le32(crc);
231}
232
233static void
234nilfs_segbuf_fill_in_super_root_crc(struct nilfs_segment_buffer *segbuf,
235				    u32 seed)
236{
237	struct nilfs_super_root *raw_sr;
238	struct the_nilfs *nilfs = segbuf->sb_super->s_fs_info;
239	unsigned int srsize;
240	u32 crc;
241
242	raw_sr = (struct nilfs_super_root *)segbuf->sb_super_root->b_data;
243	srsize = NILFS_SR_BYTES(nilfs->ns_inode_size);
244	crc = crc32_le(seed,
245		       (unsigned char *)raw_sr + sizeof(raw_sr->sr_sum),
246		       srsize - sizeof(raw_sr->sr_sum));
247	raw_sr->sr_sum = cpu_to_le32(crc);
248}
249
250static void nilfs_release_buffers(struct list_head *list)
251{
252	struct buffer_head *bh, *n;
253
254	list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
255		list_del_init(&bh->b_assoc_buffers);
256		brelse(bh);
257	}
258}
259
260static void nilfs_segbuf_clear(struct nilfs_segment_buffer *segbuf)
261{
262	nilfs_release_buffers(&segbuf->sb_segsum_buffers);
263	nilfs_release_buffers(&segbuf->sb_payload_buffers);
264	segbuf->sb_super_root = NULL;
265}
266
267/*
268 * Iterators for segment buffers
269 */
270void nilfs_clear_logs(struct list_head *logs)
271{
272	struct nilfs_segment_buffer *segbuf;
273
274	list_for_each_entry(segbuf, logs, sb_list)
275		nilfs_segbuf_clear(segbuf);
276}
277
278void nilfs_truncate_logs(struct list_head *logs,
279			 struct nilfs_segment_buffer *last)
280{
281	struct nilfs_segment_buffer *n, *segbuf;
282
283	segbuf = list_prepare_entry(last, logs, sb_list);
284	list_for_each_entry_safe_continue(segbuf, n, logs, sb_list) {
285		list_del_init(&segbuf->sb_list);
286		nilfs_segbuf_clear(segbuf);
287		nilfs_segbuf_free(segbuf);
288	}
289}
290
291int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs)
292{
293	struct nilfs_segment_buffer *segbuf;
294	int ret = 0;
295
296	list_for_each_entry(segbuf, logs, sb_list) {
297		ret = nilfs_segbuf_write(segbuf, nilfs);
298		if (ret)
299			break;
300	}
301	return ret;
302}
303
304int nilfs_wait_on_logs(struct list_head *logs)
305{
306	struct nilfs_segment_buffer *segbuf;
307	int err, ret = 0;
308
309	list_for_each_entry(segbuf, logs, sb_list) {
310		err = nilfs_segbuf_wait(segbuf);
311		if (err && !ret)
312			ret = err;
313	}
314	return ret;
315}
316
317/**
318 * nilfs_add_checksums_on_logs - add checksums on the logs
319 * @logs: list of segment buffers storing target logs
320 * @seed: checksum seed value
321 */
322void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed)
323{
324	struct nilfs_segment_buffer *segbuf;
325
326	list_for_each_entry(segbuf, logs, sb_list) {
327		if (segbuf->sb_super_root)
328			nilfs_segbuf_fill_in_super_root_crc(segbuf, seed);
329		nilfs_segbuf_fill_in_segsum_crc(segbuf, seed);
330		nilfs_segbuf_fill_in_data_crc(segbuf, seed);
331	}
332}
333
334/*
335 * BIO operations
336 */
337static void nilfs_end_bio_write(struct bio *bio)
338{
339	struct nilfs_segment_buffer *segbuf = bio->bi_private;
340
341	if (bio->bi_status)
342		atomic_inc(&segbuf->sb_err);
343
344	bio_put(bio);
345	complete(&segbuf->sb_bio_event);
346}
347
348static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
349				   struct nilfs_write_info *wi)
350{
351	struct bio *bio = wi->bio;
352
353	bio->bi_end_io = nilfs_end_bio_write;
354	bio->bi_private = segbuf;
355	submit_bio(bio);
356	segbuf->sb_nbio++;
357
358	wi->bio = NULL;
359	wi->rest_blocks -= wi->end - wi->start;
360	wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
361	wi->start = wi->end;
362	return 0;
363}
364
365static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
366				       struct nilfs_write_info *wi)
367{
368	wi->bio = NULL;
369	wi->rest_blocks = segbuf->sb_sum.nblocks;
370	wi->max_pages = BIO_MAX_VECS;
371	wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
372	wi->start = wi->end = 0;
373	wi->blocknr = segbuf->sb_pseg_start;
374}
375
376static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf,
377				  struct nilfs_write_info *wi,
378				  struct buffer_head *bh)
379{
380	int err;
381
382	BUG_ON(wi->nr_vecs <= 0);
383 repeat:
384	if (!wi->bio) {
385		wi->bio = bio_alloc(wi->nilfs->ns_bdev, wi->nr_vecs,
386				    REQ_OP_WRITE, GFP_NOIO);
387		wi->bio->bi_iter.bi_sector = (wi->blocknr + wi->end) <<
388			(wi->nilfs->ns_blocksize_bits - 9);
389	}
390
391	if (bio_add_folio(wi->bio, bh->b_folio, bh->b_size,
392			  offset_in_folio(bh->b_folio, bh->b_data))) {
393		wi->end++;
394		return 0;
395	}
396	/* bio is FULL */
397	err = nilfs_segbuf_submit_bio(segbuf, wi);
398	/* never submit current bh */
399	if (likely(!err))
400		goto repeat;
401	return err;
402}
403
404/**
405 * nilfs_segbuf_write - submit write requests of a log
406 * @segbuf: buffer storing a log to be written
407 * @nilfs: nilfs object
408 *
409 * Return: Always 0.
410 */
411static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
412			      struct the_nilfs *nilfs)
413{
414	struct nilfs_write_info wi;
415	struct buffer_head *bh;
416	int res = 0;
417
418	wi.nilfs = nilfs;
419	nilfs_segbuf_prepare_write(segbuf, &wi);
420
421	list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
422		res = nilfs_segbuf_submit_bh(segbuf, &wi, bh);
423		if (unlikely(res))
424			goto failed_bio;
425	}
426
427	list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
428		res = nilfs_segbuf_submit_bh(segbuf, &wi, bh);
429		if (unlikely(res))
430			goto failed_bio;
431	}
432
433	if (wi.bio) {
434		/*
435		 * Last BIO is always sent through the following
436		 * submission.
437		 */
438		wi.bio->bi_opf |= REQ_SYNC;
439		res = nilfs_segbuf_submit_bio(segbuf, &wi);
440	}
441
442 failed_bio:
443	return res;
444}
445
446/**
447 * nilfs_segbuf_wait - wait for completion of requested BIOs
448 * @segbuf: segment buffer
449 *
450 * Return: 0 on success, or %-EIO if I/O error is detected.
451 */
452static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf)
453{
454	int err = 0;
455
456	if (!segbuf->sb_nbio)
457		return 0;
458
459	do {
460		wait_for_completion(&segbuf->sb_bio_event);
461	} while (--segbuf->sb_nbio > 0);
462
463	if (unlikely(atomic_read(&segbuf->sb_err) > 0)) {
464		nilfs_err(segbuf->sb_super,
465			  "I/O error writing log (start-blocknr=%llu, block-count=%lu) in segment %llu",
466			  (unsigned long long)segbuf->sb_pseg_start,
467			  segbuf->sb_sum.nblocks,
468			  (unsigned long long)segbuf->sb_segnum);
469		err = -EIO;
470	}
471	return err;
472}