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TOMOYO Linux Cross Reference
Linux/fs/nilfs2/segbuf.c

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  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  * Written by Ryusuke Konishi.
 17  *
 18  */
 19 
 20 #include <linux/buffer_head.h>
 21 #include <linux/writeback.h>
 22 #include <linux/crc32.h>
 23 #include <linux/backing-dev.h>
 24 #include <linux/slab.h>
 25 #include "page.h"
 26 #include "segbuf.h"
 27 
 28 
 29 struct nilfs_write_info {
 30         struct the_nilfs       *nilfs;
 31         struct bio             *bio;
 32         int                     start, end; /* The region to be submitted */
 33         int                     rest_blocks;
 34         int                     max_pages;
 35         int                     nr_vecs;
 36         sector_t                blocknr;
 37 };
 38 
 39 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
 40                               struct the_nilfs *nilfs);
 41 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf);
 42 
 43 struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb)
 44 {
 45         struct nilfs_segment_buffer *segbuf;
 46 
 47         segbuf = kmem_cache_alloc(nilfs_segbuf_cachep, GFP_NOFS);
 48         if (unlikely(!segbuf))
 49                 return NULL;
 50 
 51         segbuf->sb_super = sb;
 52         INIT_LIST_HEAD(&segbuf->sb_list);
 53         INIT_LIST_HEAD(&segbuf->sb_segsum_buffers);
 54         INIT_LIST_HEAD(&segbuf->sb_payload_buffers);
 55         segbuf->sb_super_root = NULL;
 56 
 57         init_completion(&segbuf->sb_bio_event);
 58         atomic_set(&segbuf->sb_err, 0);
 59         segbuf->sb_nbio = 0;
 60 
 61         return segbuf;
 62 }
 63 
 64 void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
 65 {
 66         kmem_cache_free(nilfs_segbuf_cachep, segbuf);
 67 }
 68 
 69 void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
 70                      unsigned long offset, struct the_nilfs *nilfs)
 71 {
 72         segbuf->sb_segnum = segnum;
 73         nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start,
 74                                 &segbuf->sb_fseg_end);
 75 
 76         segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset;
 77         segbuf->sb_rest_blocks =
 78                 segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
 79 }
 80 
 81 /**
 82  * nilfs_segbuf_map_cont - map a new log behind a given log
 83  * @segbuf: new segment buffer
 84  * @prev: segment buffer containing a log to be continued
 85  */
 86 void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
 87                            struct nilfs_segment_buffer *prev)
 88 {
 89         segbuf->sb_segnum = prev->sb_segnum;
 90         segbuf->sb_fseg_start = prev->sb_fseg_start;
 91         segbuf->sb_fseg_end = prev->sb_fseg_end;
 92         segbuf->sb_pseg_start = prev->sb_pseg_start + prev->sb_sum.nblocks;
 93         segbuf->sb_rest_blocks =
 94                 segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
 95 }
 96 
 97 void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf,
 98                                   __u64 nextnum, struct the_nilfs *nilfs)
 99 {
100         segbuf->sb_nextnum = nextnum;
101         segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum);
102 }
103 
104 int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf)
105 {
106         struct buffer_head *bh;
107 
108         bh = sb_getblk(segbuf->sb_super,
109                        segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk);
110         if (unlikely(!bh))
111                 return -ENOMEM;
112 
113         nilfs_segbuf_add_segsum_buffer(segbuf, bh);
114         return 0;
115 }
116 
117 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
118                                 struct buffer_head **bhp)
119 {
120         struct buffer_head *bh;
121 
122         bh = sb_getblk(segbuf->sb_super,
123                        segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
124         if (unlikely(!bh))
125                 return -ENOMEM;
126 
127         nilfs_segbuf_add_payload_buffer(segbuf, bh);
128         *bhp = bh;
129         return 0;
130 }
131 
132 int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned int flags,
133                        time_t ctime, __u64 cno)
134 {
135         int err;
136 
137         segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
138         err = nilfs_segbuf_extend_segsum(segbuf);
139         if (unlikely(err))
140                 return err;
141 
142         segbuf->sb_sum.flags = flags;
143         segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
144         segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
145         segbuf->sb_sum.ctime = ctime;
146         segbuf->sb_sum.cno = cno;
147         return 0;
148 }
149 
150 /*
151  * Setup segment summary
152  */
153 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
154 {
155         struct nilfs_segment_summary *raw_sum;
156         struct buffer_head *bh_sum;
157 
158         bh_sum = list_entry(segbuf->sb_segsum_buffers.next,
159                             struct buffer_head, b_assoc_buffers);
160         raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data;
161 
162         raw_sum->ss_magic    = cpu_to_le32(NILFS_SEGSUM_MAGIC);
163         raw_sum->ss_bytes    = cpu_to_le16(sizeof(*raw_sum));
164         raw_sum->ss_flags    = cpu_to_le16(segbuf->sb_sum.flags);
165         raw_sum->ss_seq      = cpu_to_le64(segbuf->sb_sum.seg_seq);
166         raw_sum->ss_create   = cpu_to_le64(segbuf->sb_sum.ctime);
167         raw_sum->ss_next     = cpu_to_le64(segbuf->sb_sum.next);
168         raw_sum->ss_nblocks  = cpu_to_le32(segbuf->sb_sum.nblocks);
169         raw_sum->ss_nfinfo   = cpu_to_le32(segbuf->sb_sum.nfinfo);
170         raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
171         raw_sum->ss_pad      = 0;
172         raw_sum->ss_cno      = cpu_to_le64(segbuf->sb_sum.cno);
173 }
174 
175 /*
176  * CRC calculation routines
177  */
178 static void
179 nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf, u32 seed)
180 {
181         struct buffer_head *bh;
182         struct nilfs_segment_summary *raw_sum;
183         unsigned long size, bytes = segbuf->sb_sum.sumbytes;
184         u32 crc;
185 
186         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
187                         b_assoc_buffers);
188 
189         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
190         size = min_t(unsigned long, bytes, bh->b_size);
191         crc = crc32_le(seed,
192                        (unsigned char *)raw_sum +
193                        sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
194                        size - (sizeof(raw_sum->ss_datasum) +
195                                sizeof(raw_sum->ss_sumsum)));
196 
197         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
198                                      b_assoc_buffers) {
199                 bytes -= size;
200                 size = min_t(unsigned long, bytes, bh->b_size);
201                 crc = crc32_le(crc, bh->b_data, size);
202         }
203         raw_sum->ss_sumsum = cpu_to_le32(crc);
204 }
205 
206 static void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
207                                           u32 seed)
208 {
209         struct buffer_head *bh;
210         struct nilfs_segment_summary *raw_sum;
211         void *kaddr;
212         u32 crc;
213 
214         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
215                         b_assoc_buffers);
216         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
217         crc = crc32_le(seed,
218                        (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
219                        bh->b_size - sizeof(raw_sum->ss_datasum));
220 
221         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
222                                      b_assoc_buffers) {
223                 crc = crc32_le(crc, bh->b_data, bh->b_size);
224         }
225         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
226                 kaddr = kmap_atomic(bh->b_page);
227                 crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
228                 kunmap_atomic(kaddr);
229         }
230         raw_sum->ss_datasum = cpu_to_le32(crc);
231 }
232 
233 static void
234 nilfs_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 
250 static 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 
260 static 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  */
270 void 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 
278 void 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 
291 int 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 
304 int 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  */
322 void 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  */
337 static 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 
348 static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
349                                    struct nilfs_write_info *wi, int mode,
350                                    int mode_flags)
351 {
352         struct bio *bio = wi->bio;
353         int err;
354 
355         if (segbuf->sb_nbio > 0 &&
356             bdi_write_congested(segbuf->sb_super->s_bdi)) {
357                 wait_for_completion(&segbuf->sb_bio_event);
358                 segbuf->sb_nbio--;
359                 if (unlikely(atomic_read(&segbuf->sb_err))) {
360                         bio_put(bio);
361                         err = -EIO;
362                         goto failed;
363                 }
364         }
365 
366         bio->bi_end_io = nilfs_end_bio_write;
367         bio->bi_private = segbuf;
368         bio_set_op_attrs(bio, mode, mode_flags);
369         submit_bio(bio);
370         segbuf->sb_nbio++;
371 
372         wi->bio = NULL;
373         wi->rest_blocks -= wi->end - wi->start;
374         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
375         wi->start = wi->end;
376         return 0;
377 
378  failed:
379         wi->bio = NULL;
380         return err;
381 }
382 
383 /**
384  * nilfs_alloc_seg_bio - allocate a new bio for writing log
385  * @nilfs: nilfs object
386  * @start: start block number of the bio
387  * @nr_vecs: request size of page vector.
388  *
389  * Return Value: On success, pointer to the struct bio is returned.
390  * On error, NULL is returned.
391  */
392 static struct bio *nilfs_alloc_seg_bio(struct the_nilfs *nilfs, sector_t start,
393                                        int nr_vecs)
394 {
395         struct bio *bio;
396 
397         bio = bio_alloc(GFP_NOIO, nr_vecs);
398         if (bio == NULL) {
399                 while (!bio && (nr_vecs >>= 1))
400                         bio = bio_alloc(GFP_NOIO, nr_vecs);
401         }
402         if (likely(bio)) {
403                 bio->bi_bdev = nilfs->ns_bdev;
404                 bio->bi_iter.bi_sector =
405                         start << (nilfs->ns_blocksize_bits - 9);
406         }
407         return bio;
408 }
409 
410 static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
411                                        struct nilfs_write_info *wi)
412 {
413         wi->bio = NULL;
414         wi->rest_blocks = segbuf->sb_sum.nblocks;
415         wi->max_pages = BIO_MAX_PAGES;
416         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
417         wi->start = wi->end = 0;
418         wi->blocknr = segbuf->sb_pseg_start;
419 }
420 
421 static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf,
422                                   struct nilfs_write_info *wi,
423                                   struct buffer_head *bh, int mode)
424 {
425         int len, err;
426 
427         BUG_ON(wi->nr_vecs <= 0);
428  repeat:
429         if (!wi->bio) {
430                 wi->bio = nilfs_alloc_seg_bio(wi->nilfs, wi->blocknr + wi->end,
431                                               wi->nr_vecs);
432                 if (unlikely(!wi->bio))
433                         return -ENOMEM;
434         }
435 
436         len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));
437         if (len == bh->b_size) {
438                 wi->end++;
439                 return 0;
440         }
441         /* bio is FULL */
442         err = nilfs_segbuf_submit_bio(segbuf, wi, mode, 0);
443         /* never submit current bh */
444         if (likely(!err))
445                 goto repeat;
446         return err;
447 }
448 
449 /**
450  * nilfs_segbuf_write - submit write requests of a log
451  * @segbuf: buffer storing a log to be written
452  * @nilfs: nilfs object
453  *
454  * Return Value: On Success, 0 is returned. On Error, one of the following
455  * negative error code is returned.
456  *
457  * %-EIO - I/O error
458  *
459  * %-ENOMEM - Insufficient memory available.
460  */
461 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
462                               struct the_nilfs *nilfs)
463 {
464         struct nilfs_write_info wi;
465         struct buffer_head *bh;
466         int res = 0;
467 
468         wi.nilfs = nilfs;
469         nilfs_segbuf_prepare_write(segbuf, &wi);
470 
471         list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
472                 res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, REQ_OP_WRITE);
473                 if (unlikely(res))
474                         goto failed_bio;
475         }
476 
477         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
478                 res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, REQ_OP_WRITE);
479                 if (unlikely(res))
480                         goto failed_bio;
481         }
482 
483         if (wi.bio) {
484                 /*
485                  * Last BIO is always sent through the following
486                  * submission.
487                  */
488                 res = nilfs_segbuf_submit_bio(segbuf, &wi, REQ_OP_WRITE,
489                                               REQ_SYNC);
490         }
491 
492  failed_bio:
493         return res;
494 }
495 
496 /**
497  * nilfs_segbuf_wait - wait for completion of requested BIOs
498  * @segbuf: segment buffer
499  *
500  * Return Value: On Success, 0 is returned. On Error, one of the following
501  * negative error code is returned.
502  *
503  * %-EIO - I/O error
504  */
505 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf)
506 {
507         int err = 0;
508 
509         if (!segbuf->sb_nbio)
510                 return 0;
511 
512         do {
513                 wait_for_completion(&segbuf->sb_bio_event);
514         } while (--segbuf->sb_nbio > 0);
515 
516         if (unlikely(atomic_read(&segbuf->sb_err) > 0)) {
517                 nilfs_msg(segbuf->sb_super, KERN_ERR,
518                           "I/O error writing log (start-blocknr=%llu, block-count=%lu) in segment %llu",
519                           (unsigned long long)segbuf->sb_pseg_start,
520                           segbuf->sb_sum.nblocks,
521                           (unsigned long long)segbuf->sb_segnum);
522                 err = -EIO;
523         }
524         return err;
525 }
526 

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