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