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_error) 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 { 351 struct bio *bio = wi->bio; 352 int err; 353 354 if (segbuf->sb_nbio > 0 && 355 bdi_write_congested(segbuf->sb_super->s_bdi)) { 356 wait_for_completion(&segbuf->sb_bio_event); 357 segbuf->sb_nbio--; 358 if (unlikely(atomic_read(&segbuf->sb_err))) { 359 bio_put(bio); 360 err = -EIO; 361 goto failed; 362 } 363 } 364 365 bio->bi_end_io = nilfs_end_bio_write; 366 bio->bi_private = segbuf; 367 submit_bio(mode, bio); 368 segbuf->sb_nbio++; 369 370 wi->bio = NULL; 371 wi->rest_blocks -= wi->end - wi->start; 372 wi->nr_vecs = min(wi->max_pages, wi->rest_blocks); 373 wi->start = wi->end; 374 return 0; 375 376 failed: 377 wi->bio = NULL; 378 return err; 379 } 380 381 /** 382 * nilfs_alloc_seg_bio - allocate a new bio for writing log 383 * @nilfs: nilfs object 384 * @start: start block number of the bio 385 * @nr_vecs: request size of page vector. 386 * 387 * Return Value: On success, pointer to the struct bio is returned. 388 * On error, NULL is returned. 389 */ 390 static struct bio *nilfs_alloc_seg_bio(struct the_nilfs *nilfs, sector_t start, 391 int nr_vecs) 392 { 393 struct bio *bio; 394 395 bio = bio_alloc(GFP_NOIO, nr_vecs); 396 if (bio == NULL) { 397 while (!bio && (nr_vecs >>= 1)) 398 bio = bio_alloc(GFP_NOIO, nr_vecs); 399 } 400 if (likely(bio)) { 401 bio->bi_bdev = nilfs->ns_bdev; 402 bio->bi_iter.bi_sector = 403 start << (nilfs->ns_blocksize_bits - 9); 404 } 405 return bio; 406 } 407 408 static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf, 409 struct nilfs_write_info *wi) 410 { 411 wi->bio = NULL; 412 wi->rest_blocks = segbuf->sb_sum.nblocks; 413 wi->max_pages = BIO_MAX_PAGES; 414 wi->nr_vecs = min(wi->max_pages, wi->rest_blocks); 415 wi->start = wi->end = 0; 416 wi->blocknr = segbuf->sb_pseg_start; 417 } 418 419 static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf, 420 struct nilfs_write_info *wi, 421 struct buffer_head *bh, int mode) 422 { 423 int len, err; 424 425 BUG_ON(wi->nr_vecs <= 0); 426 repeat: 427 if (!wi->bio) { 428 wi->bio = nilfs_alloc_seg_bio(wi->nilfs, wi->blocknr + wi->end, 429 wi->nr_vecs); 430 if (unlikely(!wi->bio)) 431 return -ENOMEM; 432 } 433 434 len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh)); 435 if (len == bh->b_size) { 436 wi->end++; 437 return 0; 438 } 439 /* bio is FULL */ 440 err = nilfs_segbuf_submit_bio(segbuf, wi, mode); 441 /* never submit current bh */ 442 if (likely(!err)) 443 goto repeat; 444 return err; 445 } 446 447 /** 448 * nilfs_segbuf_write - submit write requests of a log 449 * @segbuf: buffer storing a log to be written 450 * @nilfs: nilfs object 451 * 452 * Return Value: On Success, 0 is returned. On Error, one of the following 453 * negative error code is returned. 454 * 455 * %-EIO - I/O error 456 * 457 * %-ENOMEM - Insufficient memory available. 458 */ 459 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf, 460 struct the_nilfs *nilfs) 461 { 462 struct nilfs_write_info wi; 463 struct buffer_head *bh; 464 int res = 0, rw = WRITE; 465 466 wi.nilfs = nilfs; 467 nilfs_segbuf_prepare_write(segbuf, &wi); 468 469 list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) { 470 res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, rw); 471 if (unlikely(res)) 472 goto failed_bio; 473 } 474 475 list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) { 476 res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, rw); 477 if (unlikely(res)) 478 goto failed_bio; 479 } 480 481 if (wi.bio) { 482 /* 483 * Last BIO is always sent through the following 484 * submission. 485 */ 486 rw |= REQ_SYNC; 487 res = nilfs_segbuf_submit_bio(segbuf, &wi, rw); 488 } 489 490 failed_bio: 491 return res; 492 } 493 494 /** 495 * nilfs_segbuf_wait - wait for completion of requested BIOs 496 * @segbuf: segment buffer 497 * 498 * Return Value: On Success, 0 is returned. On Error, one of the following 499 * negative error code is returned. 500 * 501 * %-EIO - I/O error 502 */ 503 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf) 504 { 505 int err = 0; 506 507 if (!segbuf->sb_nbio) 508 return 0; 509 510 do { 511 wait_for_completion(&segbuf->sb_bio_event); 512 } while (--segbuf->sb_nbio > 0); 513 514 if (unlikely(atomic_read(&segbuf->sb_err) > 0)) { 515 printk(KERN_ERR "NILFS: IO error writing segment\n"); 516 err = -EIO; 517 } 518 return err; 519 } 520