fs/nilfs2/mdt.c

   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 "segment.h"
  32 #include "page.h"
  33 #include "mdt.h"
  34
  35
  36 #define NILFS_MDT_MAX_RA_BLOCKS         (16 - 1)
  37
  38 #define INIT_UNUSED_INODE_FIELDS
  39
  40 static int
  41 nilfs_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, KM_USER0);
  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, KM_USER0);
  67
  68         set_buffer_uptodate(bh);
  69         nilfs_mark_buffer_dirty(bh);
  70         nilfs_mdt_mark_dirty(inode);
  71         return 0;
  72 }
  73
  74 static 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 the_nilfs *nilfs = NILFS_MDT(inode)->mi_nilfs;
  81         struct super_block *sb = inode->i_sb;
  82         struct nilfs_transaction_info ti;
  83         struct buffer_head *bh;
  84         int err;
  85
  86         if (!sb) {
  87                 /*
  88                  * Make sure this function is not called from any
  89                  * read-only context.
  90                  */
  91                 if (!nilfs->ns_writer) {
  92                         WARN_ON(1);
  93                         err = -EROFS;
  94                         goto out;
  95                 }
  96                 sb = nilfs->ns_writer->s_super;
  97         }
  98
  99         nilfs_transaction_begin(sb, &ti, 0);
 100
 101         err = -ENOMEM;
 102         bh = nilfs_grab_buffer(inode, inode->i_mapping, block, 0);
 103         if (unlikely(!bh))
 104                 goto failed_unlock;
 105
 106         err = -EEXIST;
 107         if (buffer_uptodate(bh))
 108                 goto failed_bh;
 109
 110         wait_on_buffer(bh);
 111         if (buffer_uptodate(bh))
 112                 goto failed_bh;
 113
 114         bh->b_bdev = nilfs->ns_bdev;
 115         err = nilfs_mdt_insert_new_block(inode, block, bh, init_block);
 116         if (likely(!err)) {
 117                 get_bh(bh);
 118                 *out_bh = bh;
 119         }
 120
 121  failed_bh:
 122         unlock_page(bh->b_page);
 123         page_cache_release(bh->b_page);
 124         brelse(bh);
 125
 126  failed_unlock:
 127         if (likely(!err))
 128                 err = nilfs_transaction_commit(sb);
 129         else
 130                 nilfs_transaction_abort(sb);
 131  out:
 132         return err;
 133 }
 134
 135 static int
 136 nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
 137                        int mode, struct buffer_head **out_bh)
 138 {
 139         struct buffer_head *bh;
 140         __u64 blknum = 0;
 141         int ret = -ENOMEM;
 142
 143         bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
 144         if (unlikely(!bh))
 145                 goto failed;
 146
 147         ret = -EEXIST; /* internal code */
 148         if (buffer_uptodate(bh))
 149                 goto out;
 150
 151         if (mode == READA) {
 152                 if (!trylock_buffer(bh)) {
 153                         ret = -EBUSY;
 154                         goto failed_bh;
 155                 }
 156         } else /* mode == READ */
 157                 lock_buffer(bh);
 158
 159         if (buffer_uptodate(bh)) {
 160                 unlock_buffer(bh);
 161                 goto out;
 162         }
 163
 164         ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum);
 165         if (unlikely(ret)) {
 166                 unlock_buffer(bh);
 167                 goto failed_bh;
 168         }
 169         bh->b_bdev = NILFS_MDT(inode)->mi_nilfs->ns_bdev;
 170         bh->b_blocknr = (sector_t)blknum;
 171         set_buffer_mapped(bh);
 172
 173         bh->b_end_io = end_buffer_read_sync;
 174         get_bh(bh);
 175         submit_bh(mode, bh);
 176         ret = 0;
 177  out:
 178         get_bh(bh);
 179         *out_bh = bh;
 180
 181  failed_bh:
 182         unlock_page(bh->b_page);
 183         page_cache_release(bh->b_page);
 184         brelse(bh);
 185  failed:
 186         return ret;
 187 }
 188
 189 static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
 190                                 int readahead, struct buffer_head **out_bh)
 191 {
 192         struct buffer_head *first_bh, *bh;
 193         unsigned long blkoff;
 194         int i, nr_ra_blocks = NILFS_MDT_MAX_RA_BLOCKS;
 195         int err;
 196
 197         err = nilfs_mdt_submit_block(inode, block, READ, &first_bh);
 198         if (err == -EEXIST) /* internal code */
 199                 goto out;
 200
 201         if (unlikely(err))
 202                 goto failed;
 203
 204         if (readahead) {
 205                 blkoff = block + 1;
 206                 for (i = 0; i < nr_ra_blocks; i++, blkoff++) {
 207                         err = nilfs_mdt_submit_block(inode, blkoff, READA, &bh);
 208                         if (likely(!err || err == -EEXIST))
 209                                 brelse(bh);
 210                         else if (err != -EBUSY)
 211                                 break;
 212                                 /* abort readahead if bmap lookup failed */
 213                         if (!buffer_locked(first_bh))
 214                                 goto out_no_wait;
 215                 }
 216         }
 217
 218         wait_on_buffer(first_bh);
 219
 220  out_no_wait:
 221         err = -EIO;
 222         if (!buffer_uptodate(first_bh))
 223                 goto failed_bh;
 224  out:
 225         *out_bh = first_bh;
 226         return 0;
 227
 228  failed_bh:
 229         brelse(first_bh);
 230  failed:
 231         return err;
 232 }
 233
 234 /**
 235  * nilfs_mdt_get_block - read or create a buffer on meta data file.
 236  * @inode: inode of the meta data file
 237  * @blkoff: block offset
 238  * @create: create flag
 239  * @init_block: initializer used for newly allocated block
 240  * @out_bh: output of a pointer to the buffer_head
 241  *
 242  * nilfs_mdt_get_block() looks up the specified buffer and tries to create
 243  * a new buffer if @create is not zero.  On success, the returned buffer is
 244  * assured to be either existing or formatted using a buffer lock on success.
 245  * @out_bh is substituted only when zero is returned.
 246  *
 247  * Return Value: On success, it returns 0. On error, the following negative
 248  * error code is returned.
 249  *
 250  * %-ENOMEM - Insufficient memory available.
 251  *
 252  * %-EIO - I/O error
 253  *
 254  * %-ENOENT - the specified block does not exist (hole block)
 255  *
 256  * %-EINVAL - bmap is broken. (the caller should call nilfs_error())
 257  *
 258  * %-EROFS - Read only filesystem (for create mode)
 259  */
 260 int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create,
 261                         void (*init_block)(struct inode *,
 262                                            struct buffer_head *, void *),
 263                         struct buffer_head **out_bh)
 264 {
 265         int ret;
 266
 267         /* Should be rewritten with merging nilfs_mdt_read_block() */
 268  retry:
 269         ret = nilfs_mdt_read_block(inode, blkoff, !create, out_bh);
 270         if (!create || ret != -ENOENT)
 271                 return ret;
 272
 273         ret = nilfs_mdt_create_block(inode, blkoff, out_bh, init_block);
 274         if (unlikely(ret == -EEXIST)) {
 275                 /* create = 0; */  /* limit read-create loop retries */
 276                 goto retry;
 277         }
 278         return ret;
 279 }
 280
 281 /**
 282  * nilfs_mdt_delete_block - make a hole on the meta data file.
 283  * @inode: inode of the meta data file
 284  * @block: block offset
 285  *
 286  * Return Value: On success, zero is returned.
 287  * On error, one of the following negative error code is returned.
 288  *
 289  * %-ENOMEM - Insufficient memory available.
 290  *
 291  * %-EIO - I/O error
 292  *
 293  * %-EINVAL - bmap is broken. (the caller should call nilfs_error())
 294  */
 295 int nilfs_mdt_delete_block(struct inode *inode, unsigned long block)
 296 {
 297         struct nilfs_inode_info *ii = NILFS_I(inode);
 298         int err;
 299
 300         err = nilfs_bmap_delete(ii->i_bmap, block);
 301         if (!err || err == -ENOENT) {
 302                 nilfs_mdt_mark_dirty(inode);
 303                 nilfs_mdt_forget_block(inode, block);
 304         }
 305         return err;
 306 }
 307
 308 /**
 309  * nilfs_mdt_forget_block - discard dirty state and try to remove the page
 310  * @inode: inode of the meta data file
 311  * @block: block offset
 312  *
 313  * nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and
 314  * tries to release the page including the buffer from a page cache.
 315  *
 316  * Return Value: On success, 0 is returned. On error, one of the following
 317  * negative error code is returned.
 318  *
 319  * %-EBUSY - page has an active buffer.
 320  *
 321  * %-ENOENT - page cache has no page addressed by the offset.
 322  */
 323 int nilfs_mdt_forget_block(struct inode *inode, unsigned long block)
 324 {
 325         pgoff_t index = (pgoff_t)block >>
 326                 (PAGE_CACHE_SHIFT - inode->i_blkbits);
 327         struct page *page;
 328         unsigned long first_block;
 329         int ret = 0;
 330         int still_dirty;
 331
 332         page = find_lock_page(inode->i_mapping, index);
 333         if (!page)
 334                 return -ENOENT;
 335
 336         wait_on_page_writeback(page);
 337
 338         first_block = (unsigned long)index <<
 339                 (PAGE_CACHE_SHIFT - inode->i_blkbits);
 340         if (page_has_buffers(page)) {
 341                 struct buffer_head *bh;
 342
 343                 bh = nilfs_page_get_nth_block(page, block - first_block);
 344                 nilfs_forget_buffer(bh);
 345         }
 346         still_dirty = PageDirty(page);
 347         unlock_page(page);
 348         page_cache_release(page);
 349
 350         if (still_dirty ||
 351             invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0)
 352                 ret = -EBUSY;
 353         return ret;
 354 }
 355
 356 /**
 357  * nilfs_mdt_mark_block_dirty - mark a block on the meta data file dirty.
 358  * @inode: inode of the meta data file
 359  * @block: block offset
 360  *
 361  * Return Value: On success, it returns 0. On error, the following negative
 362  * error code is returned.
 363  *
 364  * %-ENOMEM - Insufficient memory available.
 365  *
 366  * %-EIO - I/O error
 367  *
 368  * %-ENOENT - the specified block does not exist (hole block)
 369  *
 370  * %-EINVAL - bmap is broken. (the caller should call nilfs_error())
 371  */
 372 int nilfs_mdt_mark_block_dirty(struct inode *inode, unsigned long block)
 373 {
 374         struct buffer_head *bh;
 375         int err;
 376
 377         err = nilfs_mdt_read_block(inode, block, 0, &bh);
 378         if (unlikely(err))
 379                 return err;
 380         nilfs_mark_buffer_dirty(bh);
 381         nilfs_mdt_mark_dirty(inode);
 382         brelse(bh);
 383         return 0;
 384 }
 385
 386 int nilfs_mdt_fetch_dirty(struct inode *inode)
 387 {
 388         struct nilfs_inode_info *ii = NILFS_I(inode);
 389
 390         if (nilfs_bmap_test_and_clear_dirty(ii->i_bmap)) {
 391                 set_bit(NILFS_I_DIRTY, &ii->i_state);
 392                 return 1;
 393         }
 394         return test_bit(NILFS_I_DIRTY, &ii->i_state);
 395 }
 396
 397 static int
 398 nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
 399 {
 400         struct inode *inode = container_of(page->mapping,
 401                                            struct inode, i_data);
 402         struct super_block *sb = inode->i_sb;
 403         struct the_nilfs *nilfs = NILFS_MDT(inode)->mi_nilfs;
 404         struct nilfs_sb_info *writer = NULL;
 405         int err = 0;
 406
 407         redirty_page_for_writepage(wbc, page);
 408         unlock_page(page);
 409
 410         if (page->mapping->assoc_mapping)
 411                 return 0; /* Do not request flush for shadow page cache */
 412         if (!sb) {
 413                 down_read(&nilfs->ns_writer_sem);
 414                 writer = nilfs->ns_writer;
 415                 if (!writer) {
 416                         up_read(&nilfs->ns_writer_sem);
 417                         return -EROFS;
 418                 }
 419                 sb = writer->s_super;
 420         }
 421
 422         if (wbc->sync_mode == WB_SYNC_ALL)
 423                 err = nilfs_construct_segment(sb);
 424         else if (wbc->for_reclaim)
 425                 nilfs_flush_segment(sb, inode->i_ino);
 426
 427         if (writer)
 428                 up_read(&nilfs->ns_writer_sem);
 429         return err;
 430 }
 431
 432
 433 static const struct address_space_operations def_mdt_aops = {
 434         .writepage              = nilfs_mdt_write_page,
 435         .sync_page              = block_sync_page,
 436 };
 437
 438 static const struct inode_operations def_mdt_iops;
 439 static const struct file_operations def_mdt_fops;
 440
 441 /*
 442  * NILFS2 uses pseudo inodes for meta data files such as DAT, cpfile, sufile,
 443  * ifile, or gcinodes.  This allows the B-tree code and segment constructor
 444  * to treat them like regular files, and this helps to simplify the
 445  * implementation.
 446  *   On the other hand, some of the pseudo inodes have an irregular point:
 447  * They don't have valid inode->i_sb pointer because their lifetimes are
 448  * longer than those of the super block structs; they may continue for
 449  * several consecutive mounts/umounts.  This would need discussions.
 450  */
 451 /**
 452  * nilfs_mdt_new_common - allocate a pseudo inode for metadata file
 453  * @nilfs: nilfs object
 454  * @sb: super block instance the metadata file belongs to
 455  * @ino: inode number
 456  * @gfp_mask: gfp mask for data pages
 457  * @objsz: size of the private object attached to inode->i_private
 458  */
 459 struct inode *
 460 nilfs_mdt_new_common(struct the_nilfs *nilfs, struct super_block *sb,
 461                      ino_t ino, gfp_t gfp_mask, size_t objsz)
 462 {
 463         struct inode *inode = nilfs_alloc_inode_common(nilfs);
 464
 465         if (!inode)
 466                 return NULL;
 467         else {
 468                 struct address_space * const mapping = &inode->i_data;
 469                 struct nilfs_mdt_info *mi;
 470
 471                 mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS);
 472                 if (!mi) {
 473                         nilfs_destroy_inode(inode);
 474                         return NULL;
 475                 }
 476                 mi->mi_nilfs = nilfs;
 477                 init_rwsem(&mi->mi_sem);
 478
 479                 inode->i_sb = sb; /* sb may be NULL for some meta data files */
 480                 inode->i_blkbits = nilfs->ns_blocksize_bits;
 481                 inode->i_flags = 0;
 482                 atomic_set(&inode->i_count, 1);
 483                 inode->i_nlink = 1;
 484                 inode->i_ino = ino;
 485                 inode->i_mode = S_IFREG;
 486                 inode->i_private = mi;
 487
 488 #ifdef INIT_UNUSED_INODE_FIELDS
 489                 atomic_set(&inode->i_writecount, 0);
 490                 inode->i_size = 0;
 491                 inode->i_blocks = 0;
 492                 inode->i_bytes = 0;
 493                 inode->i_generation = 0;
 494 #ifdef CONFIG_QUOTA
 495                 memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
 496 #endif
 497                 inode->i_pipe = NULL;
 498                 inode->i_bdev = NULL;
 499                 inode->i_cdev = NULL;
 500                 inode->i_rdev = 0;
 501 #ifdef CONFIG_SECURITY
 502                 inode->i_security = NULL;
 503 #endif
 504                 inode->dirtied_when = 0;
 505
 506                 INIT_LIST_HEAD(&inode->i_list);
 507                 INIT_LIST_HEAD(&inode->i_sb_list);
 508                 inode->i_state = 0;
 509 #endif
 510
 511                 spin_lock_init(&inode->i_lock);
 512                 mutex_init(&inode->i_mutex);
 513                 init_rwsem(&inode->i_alloc_sem);
 514
 515                 mapping->host = NULL;  /* instead of inode */
 516                 mapping->flags = 0;
 517                 mapping_set_gfp_mask(mapping, gfp_mask);
 518                 mapping->assoc_mapping = NULL;
 519                 mapping->backing_dev_info = nilfs->ns_bdi;
 520
 521                 inode->i_mapping = mapping;
 522         }
 523
 524         return inode;
 525 }
 526
 527 struct inode *nilfs_mdt_new(struct the_nilfs *nilfs, struct super_block *sb,
 528                             ino_t ino, size_t objsz)
 529 {
 530         struct inode *inode;
 531
 532         inode = nilfs_mdt_new_common(nilfs, sb, ino, NILFS_MDT_GFP, objsz);
 533         if (!inode)
 534                 return NULL;
 535
 536         inode->i_op = &def_mdt_iops;
 537         inode->i_fop = &def_mdt_fops;
 538         inode->i_mapping->a_ops = &def_mdt_aops;
 539         return inode;
 540 }
 541
 542 void nilfs_mdt_set_entry_size(struct inode *inode, unsigned entry_size,
 543                               unsigned header_size)
 544 {
 545         struct nilfs_mdt_info *mi = NILFS_MDT(inode);
 546
 547         mi->mi_entry_size = entry_size;
 548         mi->mi_entries_per_block = (1 << inode->i_blkbits) / entry_size;
 549         mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size);
 550 }
 551
 552 void nilfs_mdt_set_shadow(struct inode *orig, struct inode *shadow)
 553 {
 554         shadow->i_mapping->assoc_mapping = orig->i_mapping;
 555         NILFS_I(shadow)->i_btnode_cache.assoc_mapping =
 556                 &NILFS_I(orig)->i_btnode_cache;
 557 }
 558
 559 static void nilfs_mdt_clear(struct inode *inode)
 560 {
 561         struct nilfs_inode_info *ii = NILFS_I(inode);
 562
 563         invalidate_mapping_pages(inode->i_mapping, 0, -1);
 564         truncate_inode_pages(inode->i_mapping, 0);
 565
 566         if (test_bit(NILFS_I_BMAP, &ii->i_state))
 567                 nilfs_bmap_clear(ii->i_bmap);
 568         nilfs_btnode_cache_clear(&ii->i_btnode_cache);
 569 }
 570
 571 void nilfs_mdt_destroy(struct inode *inode)
 572 {
 573         struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
 574
 575         if (mdi->mi_palloc_cache)
 576                 nilfs_palloc_destroy_cache(inode);
 577         nilfs_mdt_clear(inode);
 578
 579         kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
 580         kfree(mdi);
 581         nilfs_destroy_inode(inode);
 582 }