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 #include "seglist.h" 30 31 32 static struct kmem_cache *nilfs_segbuf_cachep; 33 34 static void nilfs_segbuf_init_once(void *obj) 35 { 36 memset(obj, 0, sizeof(struct nilfs_segment_buffer)); 37 } 38 39 int __init nilfs_init_segbuf_cache(void) 40 { 41 nilfs_segbuf_cachep = 42 kmem_cache_create("nilfs2_segbuf_cache", 43 sizeof(struct nilfs_segment_buffer), 44 0, SLAB_RECLAIM_ACCOUNT, 45 nilfs_segbuf_init_once); 46 47 return (nilfs_segbuf_cachep == NULL) ? -ENOMEM : 0; 48 } 49 50 void nilfs_destroy_segbuf_cache(void) 51 { 52 kmem_cache_destroy(nilfs_segbuf_cachep); 53 } 54 55 struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb) 56 { 57 struct nilfs_segment_buffer *segbuf; 58 59 segbuf = kmem_cache_alloc(nilfs_segbuf_cachep, GFP_NOFS); 60 if (unlikely(!segbuf)) 61 return NULL; 62 63 segbuf->sb_super = sb; 64 INIT_LIST_HEAD(&segbuf->sb_list); 65 INIT_LIST_HEAD(&segbuf->sb_segsum_buffers); 66 INIT_LIST_HEAD(&segbuf->sb_payload_buffers); 67 return segbuf; 68 } 69 70 void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf) 71 { 72 kmem_cache_free(nilfs_segbuf_cachep, segbuf); 73 } 74 75 void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum, 76 unsigned long offset, struct the_nilfs *nilfs) 77 { 78 segbuf->sb_segnum = segnum; 79 nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start, 80 &segbuf->sb_fseg_end); 81 82 segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset; 83 segbuf->sb_rest_blocks = 84 segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1; 85 } 86 87 void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf, 88 __u64 nextnum, struct the_nilfs *nilfs) 89 { 90 segbuf->sb_nextnum = nextnum; 91 segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum); 92 } 93 94 int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf) 95 { 96 struct buffer_head *bh; 97 98 bh = sb_getblk(segbuf->sb_super, 99 segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk); 100 if (unlikely(!bh)) 101 return -ENOMEM; 102 103 nilfs_segbuf_add_segsum_buffer(segbuf, bh); 104 return 0; 105 } 106 107 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf, 108 struct buffer_head **bhp) 109 { 110 struct buffer_head *bh; 111 112 bh = sb_getblk(segbuf->sb_super, 113 segbuf->sb_pseg_start + segbuf->sb_sum.nblocks); 114 if (unlikely(!bh)) 115 return -ENOMEM; 116 117 nilfs_segbuf_add_payload_buffer(segbuf, bh); 118 *bhp = bh; 119 return 0; 120 } 121 122 int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned flags, 123 time_t ctime) 124 { 125 int err; 126 127 segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0; 128 err = nilfs_segbuf_extend_segsum(segbuf); 129 if (unlikely(err)) 130 return err; 131 132 segbuf->sb_sum.flags = flags; 133 segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary); 134 segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0; 135 segbuf->sb_sum.ctime = ctime; 136 137 segbuf->sb_io_error = 0; 138 return 0; 139 } 140 141 /* 142 * Setup segument summary 143 */ 144 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf) 145 { 146 struct nilfs_segment_summary *raw_sum; 147 struct buffer_head *bh_sum; 148 149 bh_sum = list_entry(segbuf->sb_segsum_buffers.next, 150 struct buffer_head, b_assoc_buffers); 151 raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data; 152 153 raw_sum->ss_magic = cpu_to_le32(NILFS_SEGSUM_MAGIC); 154 raw_sum->ss_bytes = cpu_to_le16(sizeof(*raw_sum)); 155 raw_sum->ss_flags = cpu_to_le16(segbuf->sb_sum.flags); 156 raw_sum->ss_seq = cpu_to_le64(segbuf->sb_sum.seg_seq); 157 raw_sum->ss_create = cpu_to_le64(segbuf->sb_sum.ctime); 158 raw_sum->ss_next = cpu_to_le64(segbuf->sb_sum.next); 159 raw_sum->ss_nblocks = cpu_to_le32(segbuf->sb_sum.nblocks); 160 raw_sum->ss_nfinfo = cpu_to_le32(segbuf->sb_sum.nfinfo); 161 raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes); 162 raw_sum->ss_pad = 0; 163 } 164 165 /* 166 * CRC calculation routines 167 */ 168 void nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf, 169 u32 seed) 170 { 171 struct buffer_head *bh; 172 struct nilfs_segment_summary *raw_sum; 173 unsigned long size, bytes = segbuf->sb_sum.sumbytes; 174 u32 crc; 175 176 bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head, 177 b_assoc_buffers); 178 179 raw_sum = (struct nilfs_segment_summary *)bh->b_data; 180 size = min_t(unsigned long, bytes, bh->b_size); 181 crc = crc32_le(seed, 182 (unsigned char *)raw_sum + 183 sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum), 184 size - (sizeof(raw_sum->ss_datasum) + 185 sizeof(raw_sum->ss_sumsum))); 186 187 list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers, 188 b_assoc_buffers) { 189 bytes -= size; 190 size = min_t(unsigned long, bytes, bh->b_size); 191 crc = crc32_le(crc, bh->b_data, size); 192 } 193 raw_sum->ss_sumsum = cpu_to_le32(crc); 194 } 195 196 void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf, 197 u32 seed) 198 { 199 struct buffer_head *bh; 200 struct nilfs_segment_summary *raw_sum; 201 void *kaddr; 202 u32 crc; 203 204 bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head, 205 b_assoc_buffers); 206 raw_sum = (struct nilfs_segment_summary *)bh->b_data; 207 crc = crc32_le(seed, 208 (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum), 209 bh->b_size - sizeof(raw_sum->ss_datasum)); 210 211 list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers, 212 b_assoc_buffers) { 213 crc = crc32_le(crc, bh->b_data, bh->b_size); 214 } 215 list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) { 216 kaddr = kmap_atomic(bh->b_page, KM_USER0); 217 crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size); 218 kunmap_atomic(kaddr, KM_USER0); 219 } 220 raw_sum->ss_datasum = cpu_to_le32(crc); 221 } 222 223 void nilfs_release_buffers(struct list_head *list) 224 { 225 struct buffer_head *bh, *n; 226 227 list_for_each_entry_safe(bh, n, list, b_assoc_buffers) { 228 list_del_init(&bh->b_assoc_buffers); 229 if (buffer_nilfs_allocated(bh)) { 230 struct page *clone_page = bh->b_page; 231 232 /* remove clone page */ 233 brelse(bh); 234 page_cache_release(clone_page); /* for each bh */ 235 if (page_count(clone_page) <= 2) { 236 lock_page(clone_page); 237 nilfs_free_private_page(clone_page); 238 } 239 continue; 240 } 241 brelse(bh); 242 } 243 } 244 245 /* 246 * BIO operations 247 */ 248 static void nilfs_end_bio_write(struct bio *bio, int err) 249 { 250 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); 251 struct nilfs_write_info *wi = bio->bi_private; 252 253 if (err == -EOPNOTSUPP) { 254 set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); 255 bio_put(bio); 256 /* to be detected by submit_seg_bio() */ 257 } 258 259 if (!uptodate) 260 atomic_inc(&wi->err); 261 262 bio_put(bio); 263 complete(&wi->bio_event); 264 } 265 266 static int nilfs_submit_seg_bio(struct nilfs_write_info *wi, int mode) 267 { 268 struct bio *bio = wi->bio; 269 int err; 270 271 if (wi->nbio > 0 && bdi_write_congested(wi->bdi)) { 272 wait_for_completion(&wi->bio_event); 273 wi->nbio--; 274 if (unlikely(atomic_read(&wi->err))) { 275 bio_put(bio); 276 err = -EIO; 277 goto failed; 278 } 279 } 280 281 bio->bi_end_io = nilfs_end_bio_write; 282 bio->bi_private = wi; 283 bio_get(bio); 284 submit_bio(mode, bio); 285 if (bio_flagged(bio, BIO_EOPNOTSUPP)) { 286 bio_put(bio); 287 err = -EOPNOTSUPP; 288 goto failed; 289 } 290 wi->nbio++; 291 bio_put(bio); 292 293 wi->bio = NULL; 294 wi->rest_blocks -= wi->end - wi->start; 295 wi->nr_vecs = min(wi->max_pages, wi->rest_blocks); 296 wi->start = wi->end; 297 return 0; 298 299 failed: 300 wi->bio = NULL; 301 return err; 302 } 303 304 /** 305 * nilfs_alloc_seg_bio - allocate a bio for writing segment. 306 * @sb: super block 307 * @start: beginning disk block number of this BIO. 308 * @nr_vecs: request size of page vector. 309 * 310 * alloc_seg_bio() allocates a new BIO structure and initialize it. 311 * 312 * Return Value: On success, pointer to the struct bio is returned. 313 * On error, NULL is returned. 314 */ 315 static struct bio *nilfs_alloc_seg_bio(struct super_block *sb, sector_t start, 316 int nr_vecs) 317 { 318 struct bio *bio; 319 320 bio = bio_alloc(GFP_NOWAIT, nr_vecs); 321 if (bio == NULL) { 322 while (!bio && (nr_vecs >>= 1)) 323 bio = bio_alloc(GFP_NOWAIT, nr_vecs); 324 } 325 if (likely(bio)) { 326 bio->bi_bdev = sb->s_bdev; 327 bio->bi_sector = (sector_t)start << (sb->s_blocksize_bits - 9); 328 } 329 return bio; 330 } 331 332 void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf, 333 struct nilfs_write_info *wi) 334 { 335 wi->bio = NULL; 336 wi->rest_blocks = segbuf->sb_sum.nblocks; 337 wi->max_pages = bio_get_nr_vecs(wi->sb->s_bdev); 338 wi->nr_vecs = min(wi->max_pages, wi->rest_blocks); 339 wi->start = wi->end = 0; 340 wi->nbio = 0; 341 wi->blocknr = segbuf->sb_pseg_start; 342 343 atomic_set(&wi->err, 0); 344 init_completion(&wi->bio_event); 345 } 346 347 static int nilfs_submit_bh(struct nilfs_write_info *wi, struct buffer_head *bh, 348 int mode) 349 { 350 int len, err; 351 352 BUG_ON(wi->nr_vecs <= 0); 353 repeat: 354 if (!wi->bio) { 355 wi->bio = nilfs_alloc_seg_bio(wi->sb, wi->blocknr + wi->end, 356 wi->nr_vecs); 357 if (unlikely(!wi->bio)) 358 return -ENOMEM; 359 } 360 361 len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh)); 362 if (len == bh->b_size) { 363 wi->end++; 364 return 0; 365 } 366 /* bio is FULL */ 367 err = nilfs_submit_seg_bio(wi, mode); 368 /* never submit current bh */ 369 if (likely(!err)) 370 goto repeat; 371 return err; 372 } 373 374 int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf, 375 struct nilfs_write_info *wi) 376 { 377 struct buffer_head *bh; 378 int res, rw = WRITE; 379 380 list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) { 381 res = nilfs_submit_bh(wi, bh, rw); 382 if (unlikely(res)) 383 goto failed_bio; 384 } 385 386 list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) { 387 res = nilfs_submit_bh(wi, bh, rw); 388 if (unlikely(res)) 389 goto failed_bio; 390 } 391 392 if (wi->bio) { 393 /* 394 * Last BIO is always sent through the following 395 * submission. 396 */ 397 rw |= (1 << BIO_RW_SYNCIO); 398 res = nilfs_submit_seg_bio(wi, rw); 399 if (unlikely(res)) 400 goto failed_bio; 401 } 402 403 res = 0; 404 out: 405 return res; 406 407 failed_bio: 408 atomic_inc(&wi->err); 409 goto out; 410 } 411 412 /** 413 * nilfs_segbuf_wait - wait for completion of requested BIOs 414 * @wi: nilfs_write_info 415 * 416 * Return Value: On Success, 0 is returned. On Error, one of the following 417 * negative error code is returned. 418 * 419 * %-EIO - I/O error 420 */ 421 int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf, 422 struct nilfs_write_info *wi) 423 { 424 int err = 0; 425 426 if (!wi->nbio) 427 return 0; 428 429 do { 430 wait_for_completion(&wi->bio_event); 431 } while (--wi->nbio > 0); 432 433 if (unlikely(atomic_read(&wi->err) > 0)) { 434 printk(KERN_ERR "NILFS: IO error writing segment\n"); 435 err = -EIO; 436 segbuf->sb_io_error = 1; 437 } 438 return err; 439 } 440