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 "page.h" 28 #include "segbuf.h" 29 30 31 static struct kmem_cache *nilfs_segbuf_cachep; 32 33 static void nilfs_segbuf_init_once(void *obj) 34 { 35 memset(obj, 0, sizeof(struct nilfs_segment_buffer)); 36 } 37 38 int __init nilfs_init_segbuf_cache(void) 39 { 40 nilfs_segbuf_cachep = 41 kmem_cache_create("nilfs2_segbuf_cache", 42 sizeof(struct nilfs_segment_buffer), 43 0, SLAB_RECLAIM_ACCOUNT, 44 nilfs_segbuf_init_once); 45 46 return (nilfs_segbuf_cachep == NULL) ? -ENOMEM : 0; 47 } 48 49 void nilfs_destroy_segbuf_cache(void) 50 { 51 kmem_cache_destroy(nilfs_segbuf_cachep); 52 } 53 54 struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb) 55 { 56 struct nilfs_segment_buffer *segbuf; 57 58 segbuf = kmem_cache_alloc(nilfs_segbuf_cachep, GFP_NOFS); 59 if (unlikely(!segbuf)) 60 return NULL; 61 62 segbuf->sb_super = sb; 63 INIT_LIST_HEAD(&segbuf->sb_list); 64 INIT_LIST_HEAD(&segbuf->sb_segsum_buffers); 65 INIT_LIST_HEAD(&segbuf->sb_payload_buffers); 66 return segbuf; 67 } 68 69 void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf) 70 { 71 kmem_cache_free(nilfs_segbuf_cachep, segbuf); 72 } 73 74 void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum, 75 unsigned long offset, struct the_nilfs *nilfs) 76 { 77 segbuf->sb_segnum = segnum; 78 nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start, 79 &segbuf->sb_fseg_end); 80 81 segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset; 82 segbuf->sb_rest_blocks = 83 segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1; 84 } 85 86 void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf, 87 __u64 nextnum, struct the_nilfs *nilfs) 88 { 89 segbuf->sb_nextnum = nextnum; 90 segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum); 91 } 92 93 int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf) 94 { 95 struct buffer_head *bh; 96 97 bh = sb_getblk(segbuf->sb_super, 98 segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk); 99 if (unlikely(!bh)) 100 return -ENOMEM; 101 102 nilfs_segbuf_add_segsum_buffer(segbuf, bh); 103 return 0; 104 } 105 106 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf, 107 struct buffer_head **bhp) 108 { 109 struct buffer_head *bh; 110 111 bh = sb_getblk(segbuf->sb_super, 112 segbuf->sb_pseg_start + segbuf->sb_sum.nblocks); 113 if (unlikely(!bh)) 114 return -ENOMEM; 115 116 nilfs_segbuf_add_payload_buffer(segbuf, bh); 117 *bhp = bh; 118 return 0; 119 } 120 121 int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned flags, 122 time_t ctime) 123 { 124 int err; 125 126 segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0; 127 err = nilfs_segbuf_extend_segsum(segbuf); 128 if (unlikely(err)) 129 return err; 130 131 segbuf->sb_sum.flags = flags; 132 segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary); 133 segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0; 134 segbuf->sb_sum.ctime = ctime; 135 136 segbuf->sb_io_error = 0; 137 return 0; 138 } 139 140 /* 141 * Setup segument summary 142 */ 143 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf) 144 { 145 struct nilfs_segment_summary *raw_sum; 146 struct buffer_head *bh_sum; 147 148 bh_sum = list_entry(segbuf->sb_segsum_buffers.next, 149 struct buffer_head, b_assoc_buffers); 150 raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data; 151 152 raw_sum->ss_magic = cpu_to_le32(NILFS_SEGSUM_MAGIC); 153 raw_sum->ss_bytes = cpu_to_le16(sizeof(*raw_sum)); 154 raw_sum->ss_flags = cpu_to_le16(segbuf->sb_sum.flags); 155 raw_sum->ss_seq = cpu_to_le64(segbuf->sb_sum.seg_seq); 156 raw_sum->ss_create = cpu_to_le64(segbuf->sb_sum.ctime); 157 raw_sum->ss_next = cpu_to_le64(segbuf->sb_sum.next); 158 raw_sum->ss_nblocks = cpu_to_le32(segbuf->sb_sum.nblocks); 159 raw_sum->ss_nfinfo = cpu_to_le32(segbuf->sb_sum.nfinfo); 160 raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes); 161 raw_sum->ss_pad = 0; 162 } 163 164 /* 165 * CRC calculation routines 166 */ 167 void nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf, 168 u32 seed) 169 { 170 struct buffer_head *bh; 171 struct nilfs_segment_summary *raw_sum; 172 unsigned long size, bytes = segbuf->sb_sum.sumbytes; 173 u32 crc; 174 175 bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head, 176 b_assoc_buffers); 177 178 raw_sum = (struct nilfs_segment_summary *)bh->b_data; 179 size = min_t(unsigned long, bytes, bh->b_size); 180 crc = crc32_le(seed, 181 (unsigned char *)raw_sum + 182 sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum), 183 size - (sizeof(raw_sum->ss_datasum) + 184 sizeof(raw_sum->ss_sumsum))); 185 186 list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers, 187 b_assoc_buffers) { 188 bytes -= size; 189 size = min_t(unsigned long, bytes, bh->b_size); 190 crc = crc32_le(crc, bh->b_data, size); 191 } 192 raw_sum->ss_sumsum = cpu_to_le32(crc); 193 } 194 195 void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf, 196 u32 seed) 197 { 198 struct buffer_head *bh; 199 struct nilfs_segment_summary *raw_sum; 200 void *kaddr; 201 u32 crc; 202 203 bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head, 204 b_assoc_buffers); 205 raw_sum = (struct nilfs_segment_summary *)bh->b_data; 206 crc = crc32_le(seed, 207 (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum), 208 bh->b_size - sizeof(raw_sum->ss_datasum)); 209 210 list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers, 211 b_assoc_buffers) { 212 crc = crc32_le(crc, bh->b_data, bh->b_size); 213 } 214 list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) { 215 kaddr = kmap_atomic(bh->b_page, KM_USER0); 216 crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size); 217 kunmap_atomic(kaddr, KM_USER0); 218 } 219 raw_sum->ss_datasum = cpu_to_le32(crc); 220 } 221 222 void nilfs_release_buffers(struct list_head *list) 223 { 224 struct buffer_head *bh, *n; 225 226 list_for_each_entry_safe(bh, n, list, b_assoc_buffers) { 227 list_del_init(&bh->b_assoc_buffers); 228 if (buffer_nilfs_allocated(bh)) { 229 struct page *clone_page = bh->b_page; 230 231 /* remove clone page */ 232 brelse(bh); 233 page_cache_release(clone_page); /* for each bh */ 234 if (page_count(clone_page) <= 2) { 235 lock_page(clone_page); 236 nilfs_free_private_page(clone_page); 237 } 238 continue; 239 } 240 brelse(bh); 241 } 242 } 243 244 /* 245 * BIO operations 246 */ 247 static void nilfs_end_bio_write(struct bio *bio, int err) 248 { 249 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); 250 struct nilfs_write_info *wi = bio->bi_private; 251 252 if (err == -EOPNOTSUPP) { 253 set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); 254 bio_put(bio); 255 /* to be detected by submit_seg_bio() */ 256 } 257 258 if (!uptodate) 259 atomic_inc(&wi->err); 260 261 bio_put(bio); 262 complete(&wi->bio_event); 263 } 264 265 static int nilfs_submit_seg_bio(struct nilfs_write_info *wi, int mode) 266 { 267 struct bio *bio = wi->bio; 268 int err; 269 270 if (wi->nbio > 0 && bdi_write_congested(wi->bdi)) { 271 wait_for_completion(&wi->bio_event); 272 wi->nbio--; 273 if (unlikely(atomic_read(&wi->err))) { 274 bio_put(bio); 275 err = -EIO; 276 goto failed; 277 } 278 } 279 280 bio->bi_end_io = nilfs_end_bio_write; 281 bio->bi_private = wi; 282 bio_get(bio); 283 submit_bio(mode, bio); 284 if (bio_flagged(bio, BIO_EOPNOTSUPP)) { 285 bio_put(bio); 286 err = -EOPNOTSUPP; 287 goto failed; 288 } 289 wi->nbio++; 290 bio_put(bio); 291 292 wi->bio = NULL; 293 wi->rest_blocks -= wi->end - wi->start; 294 wi->nr_vecs = min(wi->max_pages, wi->rest_blocks); 295 wi->start = wi->end; 296 return 0; 297 298 failed: 299 wi->bio = NULL; 300 return err; 301 } 302 303 /** 304 * nilfs_alloc_seg_bio - allocate a bio for writing segment. 305 * @sb: super block 306 * @start: beginning disk block number of this BIO. 307 * @nr_vecs: request size of page vector. 308 * 309 * alloc_seg_bio() allocates a new BIO structure and initialize it. 310 * 311 * Return Value: On success, pointer to the struct bio is returned. 312 * On error, NULL is returned. 313 */ 314 static struct bio *nilfs_alloc_seg_bio(struct super_block *sb, sector_t start, 315 int nr_vecs) 316 { 317 struct bio *bio; 318 319 bio = bio_alloc(GFP_NOIO, nr_vecs); 320 if (bio == NULL) { 321 while (!bio && (nr_vecs >>= 1)) 322 bio = bio_alloc(GFP_NOIO, nr_vecs); 323 } 324 if (likely(bio)) { 325 bio->bi_bdev = sb->s_bdev; 326 bio->bi_sector = (sector_t)start << (sb->s_blocksize_bits - 9); 327 } 328 return bio; 329 } 330 331 void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf, 332 struct nilfs_write_info *wi) 333 { 334 wi->bio = NULL; 335 wi->rest_blocks = segbuf->sb_sum.nblocks; 336 wi->max_pages = bio_get_nr_vecs(wi->sb->s_bdev); 337 wi->nr_vecs = min(wi->max_pages, wi->rest_blocks); 338 wi->start = wi->end = 0; 339 wi->nbio = 0; 340 wi->blocknr = segbuf->sb_pseg_start; 341 342 atomic_set(&wi->err, 0); 343 init_completion(&wi->bio_event); 344 } 345 346 static int nilfs_submit_bh(struct nilfs_write_info *wi, struct buffer_head *bh, 347 int mode) 348 { 349 int len, err; 350 351 BUG_ON(wi->nr_vecs <= 0); 352 repeat: 353 if (!wi->bio) { 354 wi->bio = nilfs_alloc_seg_bio(wi->sb, wi->blocknr + wi->end, 355 wi->nr_vecs); 356 if (unlikely(!wi->bio)) 357 return -ENOMEM; 358 } 359 360 len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh)); 361 if (len == bh->b_size) { 362 wi->end++; 363 return 0; 364 } 365 /* bio is FULL */ 366 err = nilfs_submit_seg_bio(wi, mode); 367 /* never submit current bh */ 368 if (likely(!err)) 369 goto repeat; 370 return err; 371 } 372 373 int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf, 374 struct nilfs_write_info *wi) 375 { 376 struct buffer_head *bh; 377 int res, rw = WRITE; 378 379 list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) { 380 res = nilfs_submit_bh(wi, bh, rw); 381 if (unlikely(res)) 382 goto failed_bio; 383 } 384 385 list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) { 386 res = nilfs_submit_bh(wi, bh, rw); 387 if (unlikely(res)) 388 goto failed_bio; 389 } 390 391 if (wi->bio) { 392 /* 393 * Last BIO is always sent through the following 394 * submission. 395 */ 396 rw |= (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG); 397 res = nilfs_submit_seg_bio(wi, rw); 398 if (unlikely(res)) 399 goto failed_bio; 400 } 401 402 res = 0; 403 out: 404 return res; 405 406 failed_bio: 407 atomic_inc(&wi->err); 408 goto out; 409 } 410 411 /** 412 * nilfs_segbuf_wait - wait for completion of requested BIOs 413 * @wi: nilfs_write_info 414 * 415 * Return Value: On Success, 0 is returned. On Error, one of the following 416 * negative error code is returned. 417 * 418 * %-EIO - I/O error 419 */ 420 int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf, 421 struct nilfs_write_info *wi) 422 { 423 int err = 0; 424 425 if (!wi->nbio) 426 return 0; 427 428 do { 429 wait_for_completion(&wi->bio_event); 430 } while (--wi->nbio > 0); 431 432 if (unlikely(atomic_read(&wi->err) > 0)) { 433 printk(KERN_ERR "NILFS: IO error writing segment\n"); 434 err = -EIO; 435 segbuf->sb_io_error = 1; 436 } 437 return err; 438 } 439