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