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, KM_USER0); 231 crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size); 232 kunmap_atomic(kaddr, KM_USER0); 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 u32 crc; 243 244 raw_sr = (struct nilfs_super_root *)segbuf->sb_super_root->b_data; 245 crc = crc32_le(seed, 246 (unsigned char *)raw_sr + sizeof(raw_sr->sr_sum), 247 NILFS_SR_BYTES - sizeof(raw_sr->sr_sum)); 248 raw_sr->sr_sum = cpu_to_le32(crc); 249 } 250 251 static void nilfs_release_buffers(struct list_head *list) 252 { 253 struct buffer_head *bh, *n; 254 255 list_for_each_entry_safe(bh, n, list, b_assoc_buffers) { 256 list_del_init(&bh->b_assoc_buffers); 257 if (buffer_nilfs_allocated(bh)) { 258 struct page *clone_page = bh->b_page; 259 260 /* remove clone page */ 261 brelse(bh); 262 page_cache_release(clone_page); /* for each bh */ 263 if (page_count(clone_page) <= 2) { 264 lock_page(clone_page); 265 nilfs_free_private_page(clone_page); 266 } 267 continue; 268 } 269 brelse(bh); 270 } 271 } 272 273 static void nilfs_segbuf_clear(struct nilfs_segment_buffer *segbuf) 274 { 275 nilfs_release_buffers(&segbuf->sb_segsum_buffers); 276 nilfs_release_buffers(&segbuf->sb_payload_buffers); 277 segbuf->sb_super_root = NULL; 278 } 279 280 /* 281 * Iterators for segment buffers 282 */ 283 void nilfs_clear_logs(struct list_head *logs) 284 { 285 struct nilfs_segment_buffer *segbuf; 286 287 list_for_each_entry(segbuf, logs, sb_list) 288 nilfs_segbuf_clear(segbuf); 289 } 290 291 void nilfs_truncate_logs(struct list_head *logs, 292 struct nilfs_segment_buffer *last) 293 { 294 struct nilfs_segment_buffer *n, *segbuf; 295 296 segbuf = list_prepare_entry(last, logs, sb_list); 297 list_for_each_entry_safe_continue(segbuf, n, logs, sb_list) { 298 list_del_init(&segbuf->sb_list); 299 nilfs_segbuf_clear(segbuf); 300 nilfs_segbuf_free(segbuf); 301 } 302 } 303 304 int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs) 305 { 306 struct nilfs_segment_buffer *segbuf; 307 int ret = 0; 308 309 list_for_each_entry(segbuf, logs, sb_list) { 310 ret = nilfs_segbuf_write(segbuf, nilfs); 311 if (ret) 312 break; 313 } 314 return ret; 315 } 316 317 int nilfs_wait_on_logs(struct list_head *logs) 318 { 319 struct nilfs_segment_buffer *segbuf; 320 int err, ret = 0; 321 322 list_for_each_entry(segbuf, logs, sb_list) { 323 err = nilfs_segbuf_wait(segbuf); 324 if (err && !ret) 325 ret = err; 326 } 327 return ret; 328 } 329 330 /** 331 * nilfs_add_checksums_on_logs - add checksums on the logs 332 * @logs: list of segment buffers storing target logs 333 * @seed: checksum seed value 334 */ 335 void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed) 336 { 337 struct nilfs_segment_buffer *segbuf; 338 339 list_for_each_entry(segbuf, logs, sb_list) { 340 if (segbuf->sb_super_root) 341 nilfs_segbuf_fill_in_super_root_crc(segbuf, seed); 342 nilfs_segbuf_fill_in_segsum_crc(segbuf, seed); 343 nilfs_segbuf_fill_in_data_crc(segbuf, seed); 344 } 345 } 346 347 /* 348 * BIO operations 349 */ 350 static void nilfs_end_bio_write(struct bio *bio, int err) 351 { 352 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); 353 struct nilfs_segment_buffer *segbuf = bio->bi_private; 354 355 if (err == -EOPNOTSUPP) { 356 set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); 357 bio_put(bio); 358 /* to be detected by submit_seg_bio() */ 359 } 360 361 if (!uptodate) 362 atomic_inc(&segbuf->sb_err); 363 364 bio_put(bio); 365 complete(&segbuf->sb_bio_event); 366 } 367 368 static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf, 369 struct nilfs_write_info *wi, int mode) 370 { 371 struct bio *bio = wi->bio; 372 int err; 373 374 if (segbuf->sb_nbio > 0 && 375 bdi_write_congested(segbuf->sb_super->s_bdi)) { 376 wait_for_completion(&segbuf->sb_bio_event); 377 segbuf->sb_nbio--; 378 if (unlikely(atomic_read(&segbuf->sb_err))) { 379 bio_put(bio); 380 err = -EIO; 381 goto failed; 382 } 383 } 384 385 bio->bi_end_io = nilfs_end_bio_write; 386 bio->bi_private = segbuf; 387 bio_get(bio); 388 submit_bio(mode, bio); 389 if (bio_flagged(bio, BIO_EOPNOTSUPP)) { 390 bio_put(bio); 391 err = -EOPNOTSUPP; 392 goto failed; 393 } 394 segbuf->sb_nbio++; 395 bio_put(bio); 396 397 wi->bio = NULL; 398 wi->rest_blocks -= wi->end - wi->start; 399 wi->nr_vecs = min(wi->max_pages, wi->rest_blocks); 400 wi->start = wi->end; 401 return 0; 402 403 failed: 404 wi->bio = NULL; 405 return err; 406 } 407 408 /** 409 * nilfs_alloc_seg_bio - allocate a new bio for writing log 410 * @nilfs: nilfs object 411 * @start: start block number of the bio 412 * @nr_vecs: request size of page vector. 413 * 414 * Return Value: On success, pointer to the struct bio is returned. 415 * On error, NULL is returned. 416 */ 417 static struct bio *nilfs_alloc_seg_bio(struct the_nilfs *nilfs, sector_t start, 418 int nr_vecs) 419 { 420 struct bio *bio; 421 422 bio = bio_alloc(GFP_NOIO, nr_vecs); 423 if (bio == NULL) { 424 while (!bio && (nr_vecs >>= 1)) 425 bio = bio_alloc(GFP_NOIO, nr_vecs); 426 } 427 if (likely(bio)) { 428 bio->bi_bdev = nilfs->ns_bdev; 429 bio->bi_sector = start << (nilfs->ns_blocksize_bits - 9); 430 } 431 return bio; 432 } 433 434 static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf, 435 struct nilfs_write_info *wi) 436 { 437 wi->bio = NULL; 438 wi->rest_blocks = segbuf->sb_sum.nblocks; 439 wi->max_pages = bio_get_nr_vecs(wi->nilfs->ns_bdev); 440 wi->nr_vecs = min(wi->max_pages, wi->rest_blocks); 441 wi->start = wi->end = 0; 442 wi->blocknr = segbuf->sb_pseg_start; 443 } 444 445 static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf, 446 struct nilfs_write_info *wi, 447 struct buffer_head *bh, int mode) 448 { 449 int len, err; 450 451 BUG_ON(wi->nr_vecs <= 0); 452 repeat: 453 if (!wi->bio) { 454 wi->bio = nilfs_alloc_seg_bio(wi->nilfs, wi->blocknr + wi->end, 455 wi->nr_vecs); 456 if (unlikely(!wi->bio)) 457 return -ENOMEM; 458 } 459 460 len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh)); 461 if (len == bh->b_size) { 462 wi->end++; 463 return 0; 464 } 465 /* bio is FULL */ 466 err = nilfs_segbuf_submit_bio(segbuf, wi, mode); 467 /* never submit current bh */ 468 if (likely(!err)) 469 goto repeat; 470 return err; 471 } 472 473 /** 474 * nilfs_segbuf_write - submit write requests of a log 475 * @segbuf: buffer storing a log to be written 476 * @nilfs: nilfs object 477 * 478 * Return Value: On Success, 0 is returned. On Error, one of the following 479 * negative error code is returned. 480 * 481 * %-EIO - I/O error 482 * 483 * %-ENOMEM - Insufficient memory available. 484 */ 485 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf, 486 struct the_nilfs *nilfs) 487 { 488 struct nilfs_write_info wi; 489 struct buffer_head *bh; 490 int res = 0, rw = WRITE; 491 492 wi.nilfs = nilfs; 493 nilfs_segbuf_prepare_write(segbuf, &wi); 494 495 list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) { 496 res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, rw); 497 if (unlikely(res)) 498 goto failed_bio; 499 } 500 501 list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) { 502 res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, rw); 503 if (unlikely(res)) 504 goto failed_bio; 505 } 506 507 if (wi.bio) { 508 /* 509 * Last BIO is always sent through the following 510 * submission. 511 */ 512 rw |= REQ_SYNC; 513 res = nilfs_segbuf_submit_bio(segbuf, &wi, rw); 514 } 515 516 failed_bio: 517 return res; 518 } 519 520 /** 521 * nilfs_segbuf_wait - wait for completion of requested BIOs 522 * @segbuf: segment buffer 523 * 524 * Return Value: On Success, 0 is returned. On Error, one of the following 525 * negative error code is returned. 526 * 527 * %-EIO - I/O error 528 */ 529 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf) 530 { 531 int err = 0; 532 533 if (!segbuf->sb_nbio) 534 return 0; 535 536 do { 537 wait_for_completion(&segbuf->sb_bio_event); 538 } while (--segbuf->sb_nbio > 0); 539 540 if (unlikely(atomic_read(&segbuf->sb_err) > 0)) { 541 printk(KERN_ERR "NILFS: IO error writing segment\n"); 542 err = -EIO; 543 } 544 return err; 545 } 546