1 /* 2 * the_nilfs.c - the_nilfs shared structure. 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/slab.h> 26 #include <linux/blkdev.h> 27 #include <linux/backing-dev.h> 28 #include <linux/crc32.h> 29 #include "nilfs.h" 30 #include "segment.h" 31 #include "alloc.h" 32 #include "cpfile.h" 33 #include "sufile.h" 34 #include "dat.h" 35 #include "segbuf.h" 36 37 38 static LIST_HEAD(nilfs_objects); 39 static DEFINE_SPINLOCK(nilfs_lock); 40 41 void nilfs_set_last_segment(struct the_nilfs *nilfs, 42 sector_t start_blocknr, u64 seq, __u64 cno) 43 { 44 spin_lock(&nilfs->ns_last_segment_lock); 45 nilfs->ns_last_pseg = start_blocknr; 46 nilfs->ns_last_seq = seq; 47 nilfs->ns_last_cno = cno; 48 spin_unlock(&nilfs->ns_last_segment_lock); 49 } 50 51 /** 52 * alloc_nilfs - allocate the_nilfs structure 53 * @bdev: block device to which the_nilfs is related 54 * 55 * alloc_nilfs() allocates memory for the_nilfs and 56 * initializes its reference count and locks. 57 * 58 * Return Value: On success, pointer to the_nilfs is returned. 59 * On error, NULL is returned. 60 */ 61 static struct the_nilfs *alloc_nilfs(struct block_device *bdev) 62 { 63 struct the_nilfs *nilfs; 64 65 nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL); 66 if (!nilfs) 67 return NULL; 68 69 nilfs->ns_bdev = bdev; 70 atomic_set(&nilfs->ns_count, 1); 71 atomic_set(&nilfs->ns_writer_refcount, -1); 72 atomic_set(&nilfs->ns_ndirtyblks, 0); 73 init_rwsem(&nilfs->ns_sem); 74 init_rwsem(&nilfs->ns_super_sem); 75 mutex_init(&nilfs->ns_mount_mutex); 76 mutex_init(&nilfs->ns_writer_mutex); 77 INIT_LIST_HEAD(&nilfs->ns_list); 78 INIT_LIST_HEAD(&nilfs->ns_supers); 79 spin_lock_init(&nilfs->ns_last_segment_lock); 80 nilfs->ns_gc_inodes_h = NULL; 81 init_rwsem(&nilfs->ns_segctor_sem); 82 83 return nilfs; 84 } 85 86 /** 87 * find_or_create_nilfs - find or create nilfs object 88 * @bdev: block device to which the_nilfs is related 89 * 90 * find_nilfs() looks up an existent nilfs object created on the 91 * device and gets the reference count of the object. If no nilfs object 92 * is found on the device, a new nilfs object is allocated. 93 * 94 * Return Value: On success, pointer to the nilfs object is returned. 95 * On error, NULL is returned. 96 */ 97 struct the_nilfs *find_or_create_nilfs(struct block_device *bdev) 98 { 99 struct the_nilfs *nilfs, *new = NULL; 100 101 retry: 102 spin_lock(&nilfs_lock); 103 list_for_each_entry(nilfs, &nilfs_objects, ns_list) { 104 if (nilfs->ns_bdev == bdev) { 105 get_nilfs(nilfs); 106 spin_unlock(&nilfs_lock); 107 if (new) 108 put_nilfs(new); 109 return nilfs; /* existing object */ 110 } 111 } 112 if (new) { 113 list_add_tail(&new->ns_list, &nilfs_objects); 114 spin_unlock(&nilfs_lock); 115 return new; /* new object */ 116 } 117 spin_unlock(&nilfs_lock); 118 119 new = alloc_nilfs(bdev); 120 if (new) 121 goto retry; 122 return NULL; /* insufficient memory */ 123 } 124 125 /** 126 * put_nilfs - release a reference to the_nilfs 127 * @nilfs: the_nilfs structure to be released 128 * 129 * put_nilfs() decrements a reference counter of the_nilfs. 130 * If the reference count reaches zero, the_nilfs is freed. 131 */ 132 void put_nilfs(struct the_nilfs *nilfs) 133 { 134 spin_lock(&nilfs_lock); 135 if (!atomic_dec_and_test(&nilfs->ns_count)) { 136 spin_unlock(&nilfs_lock); 137 return; 138 } 139 list_del_init(&nilfs->ns_list); 140 spin_unlock(&nilfs_lock); 141 142 /* 143 * Increment of ns_count never occurs below because the caller 144 * of get_nilfs() holds at least one reference to the_nilfs. 145 * Thus its exclusion control is not required here. 146 */ 147 148 might_sleep(); 149 if (nilfs_loaded(nilfs)) { 150 nilfs_mdt_clear(nilfs->ns_sufile); 151 nilfs_mdt_destroy(nilfs->ns_sufile); 152 nilfs_mdt_clear(nilfs->ns_cpfile); 153 nilfs_mdt_destroy(nilfs->ns_cpfile); 154 nilfs_mdt_clear(nilfs->ns_dat); 155 nilfs_mdt_destroy(nilfs->ns_dat); 156 /* XXX: how and when to clear nilfs->ns_gc_dat? */ 157 nilfs_mdt_destroy(nilfs->ns_gc_dat); 158 } 159 if (nilfs_init(nilfs)) { 160 nilfs_destroy_gccache(nilfs); 161 brelse(nilfs->ns_sbh[0]); 162 brelse(nilfs->ns_sbh[1]); 163 } 164 kfree(nilfs); 165 } 166 167 static int nilfs_load_super_root(struct the_nilfs *nilfs, 168 struct nilfs_sb_info *sbi, sector_t sr_block) 169 { 170 static struct lock_class_key dat_lock_key; 171 struct buffer_head *bh_sr; 172 struct nilfs_super_root *raw_sr; 173 struct nilfs_super_block **sbp = nilfs->ns_sbp; 174 unsigned dat_entry_size, segment_usage_size, checkpoint_size; 175 unsigned inode_size; 176 int err; 177 178 err = nilfs_read_super_root_block(sbi->s_super, sr_block, &bh_sr, 1); 179 if (unlikely(err)) 180 return err; 181 182 down_read(&nilfs->ns_sem); 183 dat_entry_size = le16_to_cpu(sbp[0]->s_dat_entry_size); 184 checkpoint_size = le16_to_cpu(sbp[0]->s_checkpoint_size); 185 segment_usage_size = le16_to_cpu(sbp[0]->s_segment_usage_size); 186 up_read(&nilfs->ns_sem); 187 188 inode_size = nilfs->ns_inode_size; 189 190 err = -ENOMEM; 191 nilfs->ns_dat = nilfs_mdt_new( 192 nilfs, NULL, NILFS_DAT_INO, NILFS_DAT_GFP); 193 if (unlikely(!nilfs->ns_dat)) 194 goto failed; 195 196 nilfs->ns_gc_dat = nilfs_mdt_new( 197 nilfs, NULL, NILFS_DAT_INO, NILFS_DAT_GFP); 198 if (unlikely(!nilfs->ns_gc_dat)) 199 goto failed_dat; 200 201 nilfs->ns_cpfile = nilfs_mdt_new( 202 nilfs, NULL, NILFS_CPFILE_INO, NILFS_CPFILE_GFP); 203 if (unlikely(!nilfs->ns_cpfile)) 204 goto failed_gc_dat; 205 206 nilfs->ns_sufile = nilfs_mdt_new( 207 nilfs, NULL, NILFS_SUFILE_INO, NILFS_SUFILE_GFP); 208 if (unlikely(!nilfs->ns_sufile)) 209 goto failed_cpfile; 210 211 err = nilfs_palloc_init_blockgroup(nilfs->ns_dat, dat_entry_size); 212 if (unlikely(err)) 213 goto failed_sufile; 214 215 err = nilfs_palloc_init_blockgroup(nilfs->ns_gc_dat, dat_entry_size); 216 if (unlikely(err)) 217 goto failed_sufile; 218 219 lockdep_set_class(&NILFS_MDT(nilfs->ns_dat)->mi_sem, &dat_lock_key); 220 lockdep_set_class(&NILFS_MDT(nilfs->ns_gc_dat)->mi_sem, &dat_lock_key); 221 222 nilfs_mdt_set_shadow(nilfs->ns_dat, nilfs->ns_gc_dat); 223 nilfs_mdt_set_entry_size(nilfs->ns_cpfile, checkpoint_size, 224 sizeof(struct nilfs_cpfile_header)); 225 nilfs_mdt_set_entry_size(nilfs->ns_sufile, segment_usage_size, 226 sizeof(struct nilfs_sufile_header)); 227 228 err = nilfs_mdt_read_inode_direct( 229 nilfs->ns_dat, bh_sr, NILFS_SR_DAT_OFFSET(inode_size)); 230 if (unlikely(err)) 231 goto failed_sufile; 232 233 err = nilfs_mdt_read_inode_direct( 234 nilfs->ns_cpfile, bh_sr, NILFS_SR_CPFILE_OFFSET(inode_size)); 235 if (unlikely(err)) 236 goto failed_sufile; 237 238 err = nilfs_mdt_read_inode_direct( 239 nilfs->ns_sufile, bh_sr, NILFS_SR_SUFILE_OFFSET(inode_size)); 240 if (unlikely(err)) 241 goto failed_sufile; 242 243 raw_sr = (struct nilfs_super_root *)bh_sr->b_data; 244 nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime); 245 246 failed: 247 brelse(bh_sr); 248 return err; 249 250 failed_sufile: 251 nilfs_mdt_destroy(nilfs->ns_sufile); 252 253 failed_cpfile: 254 nilfs_mdt_destroy(nilfs->ns_cpfile); 255 256 failed_gc_dat: 257 nilfs_mdt_destroy(nilfs->ns_gc_dat); 258 259 failed_dat: 260 nilfs_mdt_destroy(nilfs->ns_dat); 261 goto failed; 262 } 263 264 static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri) 265 { 266 memset(ri, 0, sizeof(*ri)); 267 INIT_LIST_HEAD(&ri->ri_used_segments); 268 } 269 270 static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri) 271 { 272 nilfs_dispose_segment_list(&ri->ri_used_segments); 273 } 274 275 /** 276 * load_nilfs - load and recover the nilfs 277 * @nilfs: the_nilfs structure to be released 278 * @sbi: nilfs_sb_info used to recover past segment 279 * 280 * load_nilfs() searches and load the latest super root, 281 * attaches the last segment, and does recovery if needed. 282 * The caller must call this exclusively for simultaneous mounts. 283 */ 284 int load_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi) 285 { 286 struct nilfs_recovery_info ri; 287 unsigned int s_flags = sbi->s_super->s_flags; 288 int really_read_only = bdev_read_only(nilfs->ns_bdev); 289 unsigned valid_fs; 290 int err = 0; 291 292 nilfs_init_recovery_info(&ri); 293 294 down_write(&nilfs->ns_sem); 295 valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS); 296 up_write(&nilfs->ns_sem); 297 298 if (!valid_fs && (s_flags & MS_RDONLY)) { 299 printk(KERN_INFO "NILFS: INFO: recovery " 300 "required for readonly filesystem.\n"); 301 if (really_read_only) { 302 printk(KERN_ERR "NILFS: write access " 303 "unavailable, cannot proceed.\n"); 304 err = -EROFS; 305 goto failed; 306 } 307 printk(KERN_INFO "NILFS: write access will " 308 "be enabled during recovery.\n"); 309 sbi->s_super->s_flags &= ~MS_RDONLY; 310 } 311 312 err = nilfs_search_super_root(nilfs, sbi, &ri); 313 if (unlikely(err)) { 314 printk(KERN_ERR "NILFS: error searching super root.\n"); 315 goto failed; 316 } 317 318 err = nilfs_load_super_root(nilfs, sbi, ri.ri_super_root); 319 if (unlikely(err)) { 320 printk(KERN_ERR "NILFS: error loading super root.\n"); 321 goto failed; 322 } 323 324 if (!valid_fs) { 325 err = nilfs_recover_logical_segments(nilfs, sbi, &ri); 326 if (unlikely(err)) { 327 nilfs_mdt_destroy(nilfs->ns_cpfile); 328 nilfs_mdt_destroy(nilfs->ns_sufile); 329 nilfs_mdt_destroy(nilfs->ns_dat); 330 goto failed; 331 } 332 if (ri.ri_need_recovery == NILFS_RECOVERY_SR_UPDATED) 333 sbi->s_super->s_dirt = 1; 334 } 335 336 set_nilfs_loaded(nilfs); 337 338 failed: 339 nilfs_clear_recovery_info(&ri); 340 sbi->s_super->s_flags = s_flags; 341 return err; 342 } 343 344 static unsigned long long nilfs_max_size(unsigned int blkbits) 345 { 346 unsigned int max_bits; 347 unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */ 348 349 max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */ 350 if (max_bits < 64) 351 res = min_t(unsigned long long, res, (1ULL << max_bits) - 1); 352 return res; 353 } 354 355 static int nilfs_store_disk_layout(struct the_nilfs *nilfs, 356 struct nilfs_super_block *sbp) 357 { 358 if (le32_to_cpu(sbp->s_rev_level) != NILFS_CURRENT_REV) { 359 printk(KERN_ERR "NILFS: revision mismatch " 360 "(superblock rev.=%d.%d, current rev.=%d.%d). " 361 "Please check the version of mkfs.nilfs.\n", 362 le32_to_cpu(sbp->s_rev_level), 363 le16_to_cpu(sbp->s_minor_rev_level), 364 NILFS_CURRENT_REV, NILFS_MINOR_REV); 365 return -EINVAL; 366 } 367 nilfs->ns_sbsize = le16_to_cpu(sbp->s_bytes); 368 if (nilfs->ns_sbsize > BLOCK_SIZE) 369 return -EINVAL; 370 371 nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size); 372 nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino); 373 374 nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment); 375 if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) { 376 printk(KERN_ERR "NILFS: too short segment. \n"); 377 return -EINVAL; 378 } 379 380 nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block); 381 nilfs->ns_nsegments = le64_to_cpu(sbp->s_nsegments); 382 nilfs->ns_r_segments_percentage = 383 le32_to_cpu(sbp->s_r_segments_percentage); 384 nilfs->ns_nrsvsegs = 385 max_t(unsigned long, NILFS_MIN_NRSVSEGS, 386 DIV_ROUND_UP(nilfs->ns_nsegments * 387 nilfs->ns_r_segments_percentage, 100)); 388 nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed); 389 return 0; 390 } 391 392 static int nilfs_valid_sb(struct nilfs_super_block *sbp) 393 { 394 static unsigned char sum[4]; 395 const int sumoff = offsetof(struct nilfs_super_block, s_sum); 396 size_t bytes; 397 u32 crc; 398 399 if (!sbp || le16_to_cpu(sbp->s_magic) != NILFS_SUPER_MAGIC) 400 return 0; 401 bytes = le16_to_cpu(sbp->s_bytes); 402 if (bytes > BLOCK_SIZE) 403 return 0; 404 crc = crc32_le(le32_to_cpu(sbp->s_crc_seed), (unsigned char *)sbp, 405 sumoff); 406 crc = crc32_le(crc, sum, 4); 407 crc = crc32_le(crc, (unsigned char *)sbp + sumoff + 4, 408 bytes - sumoff - 4); 409 return crc == le32_to_cpu(sbp->s_sum); 410 } 411 412 static int nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset) 413 { 414 return offset < ((le64_to_cpu(sbp->s_nsegments) * 415 le32_to_cpu(sbp->s_blocks_per_segment)) << 416 (le32_to_cpu(sbp->s_log_block_size) + 10)); 417 } 418 419 static void nilfs_release_super_block(struct the_nilfs *nilfs) 420 { 421 int i; 422 423 for (i = 0; i < 2; i++) { 424 if (nilfs->ns_sbp[i]) { 425 brelse(nilfs->ns_sbh[i]); 426 nilfs->ns_sbh[i] = NULL; 427 nilfs->ns_sbp[i] = NULL; 428 } 429 } 430 } 431 432 void nilfs_fall_back_super_block(struct the_nilfs *nilfs) 433 { 434 brelse(nilfs->ns_sbh[0]); 435 nilfs->ns_sbh[0] = nilfs->ns_sbh[1]; 436 nilfs->ns_sbp[0] = nilfs->ns_sbp[1]; 437 nilfs->ns_sbh[1] = NULL; 438 nilfs->ns_sbp[1] = NULL; 439 } 440 441 void nilfs_swap_super_block(struct the_nilfs *nilfs) 442 { 443 struct buffer_head *tsbh = nilfs->ns_sbh[0]; 444 struct nilfs_super_block *tsbp = nilfs->ns_sbp[0]; 445 446 nilfs->ns_sbh[0] = nilfs->ns_sbh[1]; 447 nilfs->ns_sbp[0] = nilfs->ns_sbp[1]; 448 nilfs->ns_sbh[1] = tsbh; 449 nilfs->ns_sbp[1] = tsbp; 450 } 451 452 static int nilfs_load_super_block(struct the_nilfs *nilfs, 453 struct super_block *sb, int blocksize, 454 struct nilfs_super_block **sbpp) 455 { 456 struct nilfs_super_block **sbp = nilfs->ns_sbp; 457 struct buffer_head **sbh = nilfs->ns_sbh; 458 u64 sb2off = NILFS_SB2_OFFSET_BYTES(nilfs->ns_bdev->bd_inode->i_size); 459 int valid[2], swp = 0; 460 461 sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize, 462 &sbh[0]); 463 sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]); 464 465 if (!sbp[0]) { 466 if (!sbp[1]) { 467 printk(KERN_ERR "NILFS: unable to read superblock\n"); 468 return -EIO; 469 } 470 printk(KERN_WARNING 471 "NILFS warning: unable to read primary superblock\n"); 472 } else if (!sbp[1]) 473 printk(KERN_WARNING 474 "NILFS warning: unable to read secondary superblock\n"); 475 476 valid[0] = nilfs_valid_sb(sbp[0]); 477 valid[1] = nilfs_valid_sb(sbp[1]); 478 swp = valid[1] && 479 (!valid[0] || 480 le64_to_cpu(sbp[1]->s_wtime) > le64_to_cpu(sbp[0]->s_wtime)); 481 482 if (valid[swp] && nilfs_sb2_bad_offset(sbp[swp], sb2off)) { 483 brelse(sbh[1]); 484 sbh[1] = NULL; 485 sbp[1] = NULL; 486 swp = 0; 487 } 488 if (!valid[swp]) { 489 nilfs_release_super_block(nilfs); 490 printk(KERN_ERR "NILFS: Can't find nilfs on dev %s.\n", 491 sb->s_id); 492 return -EINVAL; 493 } 494 495 if (swp) { 496 printk(KERN_WARNING "NILFS warning: broken superblock. " 497 "using spare superblock.\n"); 498 nilfs_swap_super_block(nilfs); 499 } 500 501 nilfs->ns_sbwtime[0] = le64_to_cpu(sbp[0]->s_wtime); 502 nilfs->ns_sbwtime[1] = valid[!swp] ? le64_to_cpu(sbp[1]->s_wtime) : 0; 503 nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq); 504 *sbpp = sbp[0]; 505 return 0; 506 } 507 508 /** 509 * init_nilfs - initialize a NILFS instance. 510 * @nilfs: the_nilfs structure 511 * @sbi: nilfs_sb_info 512 * @sb: super block 513 * @data: mount options 514 * 515 * init_nilfs() performs common initialization per block device (e.g. 516 * reading the super block, getting disk layout information, initializing 517 * shared fields in the_nilfs). It takes on some portion of the jobs 518 * typically done by a fill_super() routine. This division arises from 519 * the nature that multiple NILFS instances may be simultaneously 520 * mounted on a device. 521 * For multiple mounts on the same device, only the first mount 522 * invokes these tasks. 523 * 524 * Return Value: On success, 0 is returned. On error, a negative error 525 * code is returned. 526 */ 527 int init_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, char *data) 528 { 529 struct super_block *sb = sbi->s_super; 530 struct nilfs_super_block *sbp; 531 struct backing_dev_info *bdi; 532 int blocksize; 533 int err; 534 535 down_write(&nilfs->ns_sem); 536 if (nilfs_init(nilfs)) { 537 /* Load values from existing the_nilfs */ 538 sbp = nilfs->ns_sbp[0]; 539 err = nilfs_store_magic_and_option(sb, sbp, data); 540 if (err) 541 goto out; 542 543 blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size); 544 if (sb->s_blocksize != blocksize && 545 !sb_set_blocksize(sb, blocksize)) { 546 printk(KERN_ERR "NILFS: blocksize %d unfit to device\n", 547 blocksize); 548 err = -EINVAL; 549 } 550 sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits); 551 goto out; 552 } 553 554 blocksize = sb_min_blocksize(sb, BLOCK_SIZE); 555 if (!blocksize) { 556 printk(KERN_ERR "NILFS: unable to set blocksize\n"); 557 err = -EINVAL; 558 goto out; 559 } 560 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp); 561 if (err) 562 goto out; 563 564 err = nilfs_store_magic_and_option(sb, sbp, data); 565 if (err) 566 goto failed_sbh; 567 568 blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size); 569 if (sb->s_blocksize != blocksize) { 570 int hw_blocksize = bdev_logical_block_size(sb->s_bdev); 571 572 if (blocksize < hw_blocksize) { 573 printk(KERN_ERR 574 "NILFS: blocksize %d too small for device " 575 "(sector-size = %d).\n", 576 blocksize, hw_blocksize); 577 err = -EINVAL; 578 goto failed_sbh; 579 } 580 nilfs_release_super_block(nilfs); 581 sb_set_blocksize(sb, blocksize); 582 583 err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp); 584 if (err) 585 goto out; 586 /* not failed_sbh; sbh is released automatically 587 when reloading fails. */ 588 } 589 nilfs->ns_blocksize_bits = sb->s_blocksize_bits; 590 591 err = nilfs_store_disk_layout(nilfs, sbp); 592 if (err) 593 goto failed_sbh; 594 595 sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits); 596 597 nilfs->ns_mount_state = le16_to_cpu(sbp->s_state); 598 599 bdi = nilfs->ns_bdev->bd_inode_backing_dev_info; 600 if (!bdi) 601 bdi = nilfs->ns_bdev->bd_inode->i_mapping->backing_dev_info; 602 nilfs->ns_bdi = bdi ? : &default_backing_dev_info; 603 604 /* Finding last segment */ 605 nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg); 606 nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno); 607 nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq); 608 609 nilfs->ns_seg_seq = nilfs->ns_last_seq; 610 nilfs->ns_segnum = 611 nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg); 612 nilfs->ns_cno = nilfs->ns_last_cno + 1; 613 if (nilfs->ns_segnum >= nilfs->ns_nsegments) { 614 printk(KERN_ERR "NILFS invalid last segment number.\n"); 615 err = -EINVAL; 616 goto failed_sbh; 617 } 618 /* Dummy values */ 619 nilfs->ns_free_segments_count = 620 nilfs->ns_nsegments - (nilfs->ns_segnum + 1); 621 622 /* Initialize gcinode cache */ 623 err = nilfs_init_gccache(nilfs); 624 if (err) 625 goto failed_sbh; 626 627 set_nilfs_init(nilfs); 628 err = 0; 629 out: 630 up_write(&nilfs->ns_sem); 631 return err; 632 633 failed_sbh: 634 nilfs_release_super_block(nilfs); 635 goto out; 636 } 637 638 int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks) 639 { 640 struct inode *dat = nilfs_dat_inode(nilfs); 641 unsigned long ncleansegs; 642 int err; 643 644 down_read(&NILFS_MDT(dat)->mi_sem); /* XXX */ 645 err = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile, &ncleansegs); 646 up_read(&NILFS_MDT(dat)->mi_sem); /* XXX */ 647 if (likely(!err)) 648 *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment; 649 return err; 650 } 651 652 int nilfs_near_disk_full(struct the_nilfs *nilfs) 653 { 654 struct inode *sufile = nilfs->ns_sufile; 655 unsigned long ncleansegs, nincsegs; 656 int ret; 657 658 ret = nilfs_sufile_get_ncleansegs(sufile, &ncleansegs); 659 if (likely(!ret)) { 660 nincsegs = atomic_read(&nilfs->ns_ndirtyblks) / 661 nilfs->ns_blocks_per_segment + 1; 662 if (ncleansegs <= nilfs->ns_nrsvsegs + nincsegs) 663 ret++; 664 } 665 return ret; 666 } 667 668 /** 669 * nilfs_find_sbinfo - find existing nilfs_sb_info structure 670 * @nilfs: nilfs object 671 * @rw_mount: mount type (non-zero value for read/write mount) 672 * @cno: checkpoint number (zero for read-only mount) 673 * 674 * nilfs_find_sbinfo() returns the nilfs_sb_info structure which 675 * @rw_mount and @cno (in case of snapshots) matched. If no instance 676 * was found, NULL is returned. Although the super block instance can 677 * be unmounted after this function returns, the nilfs_sb_info struct 678 * is kept on memory until nilfs_put_sbinfo() is called. 679 */ 680 struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *nilfs, 681 int rw_mount, __u64 cno) 682 { 683 struct nilfs_sb_info *sbi; 684 685 down_read(&nilfs->ns_super_sem); 686 /* 687 * The SNAPSHOT flag and sb->s_flags are supposed to be 688 * protected with nilfs->ns_super_sem. 689 */ 690 sbi = nilfs->ns_current; 691 if (rw_mount) { 692 if (sbi && !(sbi->s_super->s_flags & MS_RDONLY)) 693 goto found; /* read/write mount */ 694 else 695 goto out; 696 } else if (cno == 0) { 697 if (sbi && (sbi->s_super->s_flags & MS_RDONLY)) 698 goto found; /* read-only mount */ 699 else 700 goto out; 701 } 702 703 list_for_each_entry(sbi, &nilfs->ns_supers, s_list) { 704 if (nilfs_test_opt(sbi, SNAPSHOT) && 705 sbi->s_snapshot_cno == cno) 706 goto found; /* snapshot mount */ 707 } 708 out: 709 up_read(&nilfs->ns_super_sem); 710 return NULL; 711 712 found: 713 atomic_inc(&sbi->s_count); 714 up_read(&nilfs->ns_super_sem); 715 return sbi; 716 } 717 718 int nilfs_checkpoint_is_mounted(struct the_nilfs *nilfs, __u64 cno, 719 int snapshot_mount) 720 { 721 struct nilfs_sb_info *sbi; 722 int ret = 0; 723 724 down_read(&nilfs->ns_super_sem); 725 if (cno == 0 || cno > nilfs->ns_cno) 726 goto out_unlock; 727 728 list_for_each_entry(sbi, &nilfs->ns_supers, s_list) { 729 if (sbi->s_snapshot_cno == cno && 730 (!snapshot_mount || nilfs_test_opt(sbi, SNAPSHOT))) { 731 /* exclude read-only mounts */ 732 ret++; 733 break; 734 } 735 } 736 /* for protecting recent checkpoints */ 737 if (cno >= nilfs_last_cno(nilfs)) 738 ret++; 739 740 out_unlock: 741 up_read(&nilfs->ns_super_sem); 742 return ret; 743 } 744