1/* 2 * mdt.c - meta data file for NILFS 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#include <linux/buffer_head.h> 24#include <linux/mpage.h> 25#include <linux/mm.h> 26#include <linux/writeback.h> 27#include <linux/backing-dev.h> 28#include <linux/swap.h> 29#include <linux/slab.h> 30#include "nilfs.h" 31#include "btnode.h" 32#include "segment.h" 33#include "page.h" 34#include "mdt.h" 35 36 37#define NILFS_MDT_MAX_RA_BLOCKS (16 - 1) 38 39 40static int 41nilfs_mdt_insert_new_block(struct inode *inode, unsigned long block, 42 struct buffer_head *bh, 43 void (*init_block)(struct inode *, 44 struct buffer_head *, void *)) 45{ 46 struct nilfs_inode_info *ii = NILFS_I(inode); 47 void *kaddr; 48 int ret; 49 50 /* Caller exclude read accesses using page lock */ 51 52 /* set_buffer_new(bh); */ 53 bh->b_blocknr = 0; 54 55 ret = nilfs_bmap_insert(ii->i_bmap, block, (unsigned long)bh); 56 if (unlikely(ret)) 57 return ret; 58 59 set_buffer_mapped(bh); 60 61 kaddr = kmap_atomic(bh->b_page); 62 memset(kaddr + bh_offset(bh), 0, 1 << inode->i_blkbits); 63 if (init_block) 64 init_block(inode, bh, kaddr); 65 flush_dcache_page(bh->b_page); 66 kunmap_atomic(kaddr); 67 68 set_buffer_uptodate(bh); 69 mark_buffer_dirty(bh); 70 nilfs_mdt_mark_dirty(inode); 71 return 0; 72} 73 74static int nilfs_mdt_create_block(struct inode *inode, unsigned long block, 75 struct buffer_head **out_bh, 76 void (*init_block)(struct inode *, 77 struct buffer_head *, 78 void *)) 79{ 80 struct super_block *sb = inode->i_sb; 81 struct nilfs_transaction_info ti; 82 struct buffer_head *bh; 83 int err; 84 85 nilfs_transaction_begin(sb, &ti, 0); 86 87 err = -ENOMEM; 88 bh = nilfs_grab_buffer(inode, inode->i_mapping, block, 0); 89 if (unlikely(!bh)) 90 goto failed_unlock; 91 92 err = -EEXIST; 93 if (buffer_uptodate(bh)) 94 goto failed_bh; 95 96 wait_on_buffer(bh); 97 if (buffer_uptodate(bh)) 98 goto failed_bh; 99 100 bh->b_bdev = sb->s_bdev; 101 err = nilfs_mdt_insert_new_block(inode, block, bh, init_block); 102 if (likely(!err)) { 103 get_bh(bh); 104 *out_bh = bh; 105 } 106 107 failed_bh: 108 unlock_page(bh->b_page); 109 page_cache_release(bh->b_page); 110 brelse(bh); 111 112 failed_unlock: 113 if (likely(!err)) 114 err = nilfs_transaction_commit(sb); 115 else 116 nilfs_transaction_abort(sb); 117 118 return err; 119} 120 121static int 122nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff, 123 int mode, struct buffer_head **out_bh) 124{ 125 struct buffer_head *bh; 126 __u64 blknum = 0; 127 int ret = -ENOMEM; 128 129 bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0); 130 if (unlikely(!bh)) 131 goto failed; 132 133 ret = -EEXIST; /* internal code */ 134 if (buffer_uptodate(bh)) 135 goto out; 136 137 if (mode == READA) { 138 if (!trylock_buffer(bh)) { 139 ret = -EBUSY; 140 goto failed_bh; 141 } 142 } else /* mode == READ */ 143 lock_buffer(bh); 144 145 if (buffer_uptodate(bh)) { 146 unlock_buffer(bh); 147 goto out; 148 } 149 150 ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum); 151 if (unlikely(ret)) { 152 unlock_buffer(bh); 153 goto failed_bh; 154 } 155 map_bh(bh, inode->i_sb, (sector_t)blknum); 156 157 bh->b_end_io = end_buffer_read_sync; 158 get_bh(bh); 159 submit_bh(mode, bh); 160 ret = 0; 161 out: 162 get_bh(bh); 163 *out_bh = bh; 164 165 failed_bh: 166 unlock_page(bh->b_page); 167 page_cache_release(bh->b_page); 168 brelse(bh); 169 failed: 170 return ret; 171} 172 173static int nilfs_mdt_read_block(struct inode *inode, unsigned long block, 174 int readahead, struct buffer_head **out_bh) 175{ 176 struct buffer_head *first_bh, *bh; 177 unsigned long blkoff; 178 int i, nr_ra_blocks = NILFS_MDT_MAX_RA_BLOCKS; 179 int err; 180 181 err = nilfs_mdt_submit_block(inode, block, READ, &first_bh); 182 if (err == -EEXIST) /* internal code */ 183 goto out; 184 185 if (unlikely(err)) 186 goto failed; 187 188 if (readahead) { 189 blkoff = block + 1; 190 for (i = 0; i < nr_ra_blocks; i++, blkoff++) { 191 err = nilfs_mdt_submit_block(inode, blkoff, READA, &bh); 192 if (likely(!err || err == -EEXIST)) 193 brelse(bh); 194 else if (err != -EBUSY) 195 break; 196 /* abort readahead if bmap lookup failed */ 197 if (!buffer_locked(first_bh)) 198 goto out_no_wait; 199 } 200 } 201 202 wait_on_buffer(first_bh); 203 204 out_no_wait: 205 err = -EIO; 206 if (!buffer_uptodate(first_bh)) 207 goto failed_bh; 208 out: 209 *out_bh = first_bh; 210 return 0; 211 212 failed_bh: 213 brelse(first_bh); 214 failed: 215 return err; 216} 217 218/** 219 * nilfs_mdt_get_block - read or create a buffer on meta data file. 220 * @inode: inode of the meta data file 221 * @blkoff: block offset 222 * @create: create flag 223 * @init_block: initializer used for newly allocated block 224 * @out_bh: output of a pointer to the buffer_head 225 * 226 * nilfs_mdt_get_block() looks up the specified buffer and tries to create 227 * a new buffer if @create is not zero. On success, the returned buffer is 228 * assured to be either existing or formatted using a buffer lock on success. 229 * @out_bh is substituted only when zero is returned. 230 * 231 * Return Value: On success, it returns 0. On error, the following negative 232 * error code is returned. 233 * 234 * %-ENOMEM - Insufficient memory available. 235 * 236 * %-EIO - I/O error 237 * 238 * %-ENOENT - the specified block does not exist (hole block) 239 * 240 * %-EROFS - Read only filesystem (for create mode) 241 */ 242int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create, 243 void (*init_block)(struct inode *, 244 struct buffer_head *, void *), 245 struct buffer_head **out_bh) 246{ 247 int ret; 248 249 /* Should be rewritten with merging nilfs_mdt_read_block() */ 250 retry: 251 ret = nilfs_mdt_read_block(inode, blkoff, !create, out_bh); 252 if (!create || ret != -ENOENT) 253 return ret; 254 255 ret = nilfs_mdt_create_block(inode, blkoff, out_bh, init_block); 256 if (unlikely(ret == -EEXIST)) { 257 /* create = 0; */ /* limit read-create loop retries */ 258 goto retry; 259 } 260 return ret; 261} 262 263/** 264 * nilfs_mdt_find_block - find and get a buffer on meta data file. 265 * @inode: inode of the meta data file 266 * @start: start block offset (inclusive) 267 * @end: end block offset (inclusive) 268 * @blkoff: block offset 269 * @out_bh: place to store a pointer to buffer_head struct 270 * 271 * nilfs_mdt_find_block() looks up an existing block in range of 272 * [@start, @end] and stores pointer to a buffer head of the block to 273 * @out_bh, and block offset to @blkoff, respectively. @out_bh and 274 * @blkoff are substituted only when zero is returned. 275 * 276 * Return Value: On success, it returns 0. On error, the following negative 277 * error code is returned. 278 * 279 * %-ENOMEM - Insufficient memory available. 280 * 281 * %-EIO - I/O error 282 * 283 * %-ENOENT - no block was found in the range 284 */ 285int nilfs_mdt_find_block(struct inode *inode, unsigned long start, 286 unsigned long end, unsigned long *blkoff, 287 struct buffer_head **out_bh) 288{ 289 __u64 next; 290 int ret; 291 292 if (unlikely(start > end)) 293 return -ENOENT; 294 295 ret = nilfs_mdt_read_block(inode, start, true, out_bh); 296 if (!ret) { 297 *blkoff = start; 298 goto out; 299 } 300 if (unlikely(ret != -ENOENT || start == ULONG_MAX)) 301 goto out; 302 303 ret = nilfs_bmap_seek_key(NILFS_I(inode)->i_bmap, start + 1, &next); 304 if (!ret) { 305 if (next <= end) { 306 ret = nilfs_mdt_read_block(inode, next, true, out_bh); 307 if (!ret) 308 *blkoff = next; 309 } else { 310 ret = -ENOENT; 311 } 312 } 313out: 314 return ret; 315} 316 317/** 318 * nilfs_mdt_delete_block - make a hole on the meta data file. 319 * @inode: inode of the meta data file 320 * @block: block offset 321 * 322 * Return Value: On success, zero is returned. 323 * On error, one of the following negative error code is returned. 324 * 325 * %-ENOMEM - Insufficient memory available. 326 * 327 * %-EIO - I/O error 328 */ 329int nilfs_mdt_delete_block(struct inode *inode, unsigned long block) 330{ 331 struct nilfs_inode_info *ii = NILFS_I(inode); 332 int err; 333 334 err = nilfs_bmap_delete(ii->i_bmap, block); 335 if (!err || err == -ENOENT) { 336 nilfs_mdt_mark_dirty(inode); 337 nilfs_mdt_forget_block(inode, block); 338 } 339 return err; 340} 341 342/** 343 * nilfs_mdt_forget_block - discard dirty state and try to remove the page 344 * @inode: inode of the meta data file 345 * @block: block offset 346 * 347 * nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and 348 * tries to release the page including the buffer from a page cache. 349 * 350 * Return Value: On success, 0 is returned. On error, one of the following 351 * negative error code is returned. 352 * 353 * %-EBUSY - page has an active buffer. 354 * 355 * %-ENOENT - page cache has no page addressed by the offset. 356 */ 357int nilfs_mdt_forget_block(struct inode *inode, unsigned long block) 358{ 359 pgoff_t index = (pgoff_t)block >> 360 (PAGE_CACHE_SHIFT - inode->i_blkbits); 361 struct page *page; 362 unsigned long first_block; 363 int ret = 0; 364 int still_dirty; 365 366 page = find_lock_page(inode->i_mapping, index); 367 if (!page) 368 return -ENOENT; 369 370 wait_on_page_writeback(page); 371 372 first_block = (unsigned long)index << 373 (PAGE_CACHE_SHIFT - inode->i_blkbits); 374 if (page_has_buffers(page)) { 375 struct buffer_head *bh; 376 377 bh = nilfs_page_get_nth_block(page, block - first_block); 378 nilfs_forget_buffer(bh); 379 } 380 still_dirty = PageDirty(page); 381 unlock_page(page); 382 page_cache_release(page); 383 384 if (still_dirty || 385 invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0) 386 ret = -EBUSY; 387 return ret; 388} 389 390/** 391 * nilfs_mdt_mark_block_dirty - mark a block on the meta data file dirty. 392 * @inode: inode of the meta data file 393 * @block: block offset 394 * 395 * Return Value: On success, it returns 0. On error, the following negative 396 * error code is returned. 397 * 398 * %-ENOMEM - Insufficient memory available. 399 * 400 * %-EIO - I/O error 401 * 402 * %-ENOENT - the specified block does not exist (hole block) 403 */ 404int nilfs_mdt_mark_block_dirty(struct inode *inode, unsigned long block) 405{ 406 struct buffer_head *bh; 407 int err; 408 409 err = nilfs_mdt_read_block(inode, block, 0, &bh); 410 if (unlikely(err)) 411 return err; 412 mark_buffer_dirty(bh); 413 nilfs_mdt_mark_dirty(inode); 414 brelse(bh); 415 return 0; 416} 417 418int nilfs_mdt_fetch_dirty(struct inode *inode) 419{ 420 struct nilfs_inode_info *ii = NILFS_I(inode); 421 422 if (nilfs_bmap_test_and_clear_dirty(ii->i_bmap)) { 423 set_bit(NILFS_I_DIRTY, &ii->i_state); 424 return 1; 425 } 426 return test_bit(NILFS_I_DIRTY, &ii->i_state); 427} 428 429static int 430nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc) 431{ 432 struct inode *inode = page->mapping->host; 433 struct super_block *sb; 434 int err = 0; 435 436 if (inode && (inode->i_sb->s_flags & MS_RDONLY)) { 437 /* 438 * It means that filesystem was remounted in read-only 439 * mode because of error or metadata corruption. But we 440 * have dirty pages that try to be flushed in background. 441 * So, here we simply discard this dirty page. 442 */ 443 nilfs_clear_dirty_page(page, false); 444 unlock_page(page); 445 return -EROFS; 446 } 447 448 redirty_page_for_writepage(wbc, page); 449 unlock_page(page); 450 451 if (!inode) 452 return 0; 453 454 sb = inode->i_sb; 455 456 if (wbc->sync_mode == WB_SYNC_ALL) 457 err = nilfs_construct_segment(sb); 458 else if (wbc->for_reclaim) 459 nilfs_flush_segment(sb, inode->i_ino); 460 461 return err; 462} 463 464 465static const struct address_space_operations def_mdt_aops = { 466 .writepage = nilfs_mdt_write_page, 467}; 468 469static const struct inode_operations def_mdt_iops; 470static const struct file_operations def_mdt_fops; 471 472 473int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz) 474{ 475 struct nilfs_mdt_info *mi; 476 477 mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS); 478 if (!mi) 479 return -ENOMEM; 480 481 init_rwsem(&mi->mi_sem); 482 inode->i_private = mi; 483 484 inode->i_mode = S_IFREG; 485 mapping_set_gfp_mask(inode->i_mapping, gfp_mask); 486 487 inode->i_op = &def_mdt_iops; 488 inode->i_fop = &def_mdt_fops; 489 inode->i_mapping->a_ops = &def_mdt_aops; 490 491 return 0; 492} 493 494void nilfs_mdt_set_entry_size(struct inode *inode, unsigned entry_size, 495 unsigned header_size) 496{ 497 struct nilfs_mdt_info *mi = NILFS_MDT(inode); 498 499 mi->mi_entry_size = entry_size; 500 mi->mi_entries_per_block = (1 << inode->i_blkbits) / entry_size; 501 mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size); 502} 503 504/** 505 * nilfs_mdt_setup_shadow_map - setup shadow map and bind it to metadata file 506 * @inode: inode of the metadata file 507 * @shadow: shadow mapping 508 */ 509int nilfs_mdt_setup_shadow_map(struct inode *inode, 510 struct nilfs_shadow_map *shadow) 511{ 512 struct nilfs_mdt_info *mi = NILFS_MDT(inode); 513 514 INIT_LIST_HEAD(&shadow->frozen_buffers); 515 address_space_init_once(&shadow->frozen_data); 516 nilfs_mapping_init(&shadow->frozen_data, inode); 517 address_space_init_once(&shadow->frozen_btnodes); 518 nilfs_mapping_init(&shadow->frozen_btnodes, inode); 519 mi->mi_shadow = shadow; 520 return 0; 521} 522 523/** 524 * nilfs_mdt_save_to_shadow_map - copy bmap and dirty pages to shadow map 525 * @inode: inode of the metadata file 526 */ 527int nilfs_mdt_save_to_shadow_map(struct inode *inode) 528{ 529 struct nilfs_mdt_info *mi = NILFS_MDT(inode); 530 struct nilfs_inode_info *ii = NILFS_I(inode); 531 struct nilfs_shadow_map *shadow = mi->mi_shadow; 532 int ret; 533 534 ret = nilfs_copy_dirty_pages(&shadow->frozen_data, inode->i_mapping); 535 if (ret) 536 goto out; 537 538 ret = nilfs_copy_dirty_pages(&shadow->frozen_btnodes, 539 &ii->i_btnode_cache); 540 if (ret) 541 goto out; 542 543 nilfs_bmap_save(ii->i_bmap, &shadow->bmap_store); 544 out: 545 return ret; 546} 547 548int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh) 549{ 550 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow; 551 struct buffer_head *bh_frozen; 552 struct page *page; 553 int blkbits = inode->i_blkbits; 554 555 page = grab_cache_page(&shadow->frozen_data, bh->b_page->index); 556 if (!page) 557 return -ENOMEM; 558 559 if (!page_has_buffers(page)) 560 create_empty_buffers(page, 1 << blkbits, 0); 561 562 bh_frozen = nilfs_page_get_nth_block(page, bh_offset(bh) >> blkbits); 563 564 if (!buffer_uptodate(bh_frozen)) 565 nilfs_copy_buffer(bh_frozen, bh); 566 if (list_empty(&bh_frozen->b_assoc_buffers)) { 567 list_add_tail(&bh_frozen->b_assoc_buffers, 568 &shadow->frozen_buffers); 569 set_buffer_nilfs_redirected(bh); 570 } else { 571 brelse(bh_frozen); /* already frozen */ 572 } 573 574 unlock_page(page); 575 page_cache_release(page); 576 return 0; 577} 578 579struct buffer_head * 580nilfs_mdt_get_frozen_buffer(struct inode *inode, struct buffer_head *bh) 581{ 582 struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow; 583 struct buffer_head *bh_frozen = NULL; 584 struct page *page; 585 int n; 586 587 page = find_lock_page(&shadow->frozen_data, bh->b_page->index); 588 if (page) { 589 if (page_has_buffers(page)) { 590 n = bh_offset(bh) >> inode->i_blkbits; 591 bh_frozen = nilfs_page_get_nth_block(page, n); 592 } 593 unlock_page(page); 594 page_cache_release(page); 595 } 596 return bh_frozen; 597} 598 599static void nilfs_release_frozen_buffers(struct nilfs_shadow_map *shadow) 600{ 601 struct list_head *head = &shadow->frozen_buffers; 602 struct buffer_head *bh; 603 604 while (!list_empty(head)) { 605 bh = list_first_entry(head, struct buffer_head, 606 b_assoc_buffers); 607 list_del_init(&bh->b_assoc_buffers); 608 brelse(bh); /* drop ref-count to make it releasable */ 609 } 610} 611 612/** 613 * nilfs_mdt_restore_from_shadow_map - restore dirty pages and bmap state 614 * @inode: inode of the metadata file 615 */ 616void nilfs_mdt_restore_from_shadow_map(struct inode *inode) 617{ 618 struct nilfs_mdt_info *mi = NILFS_MDT(inode); 619 struct nilfs_inode_info *ii = NILFS_I(inode); 620 struct nilfs_shadow_map *shadow = mi->mi_shadow; 621 622 down_write(&mi->mi_sem); 623 624 if (mi->mi_palloc_cache) 625 nilfs_palloc_clear_cache(inode); 626 627 nilfs_clear_dirty_pages(inode->i_mapping, true); 628 nilfs_copy_back_pages(inode->i_mapping, &shadow->frozen_data); 629 630 nilfs_clear_dirty_pages(&ii->i_btnode_cache, true); 631 nilfs_copy_back_pages(&ii->i_btnode_cache, &shadow->frozen_btnodes); 632 633 nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store); 634 635 up_write(&mi->mi_sem); 636} 637 638/** 639 * nilfs_mdt_clear_shadow_map - truncate pages in shadow map caches 640 * @inode: inode of the metadata file 641 */ 642void nilfs_mdt_clear_shadow_map(struct inode *inode) 643{ 644 struct nilfs_mdt_info *mi = NILFS_MDT(inode); 645 struct nilfs_shadow_map *shadow = mi->mi_shadow; 646 647 down_write(&mi->mi_sem); 648 nilfs_release_frozen_buffers(shadow); 649 truncate_inode_pages(&shadow->frozen_data, 0); 650 truncate_inode_pages(&shadow->frozen_btnodes, 0); 651 up_write(&mi->mi_sem); 652} 653