err.no Git - linux-2.6/blob - fs/gfs2/ops_address.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
   4  *
   5  * This copyrighted material is made available to anyone wishing to use,
   6  * modify, copy, or redistribute it subject to the terms and conditions
   7  * of the GNU General Public License v.2.
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/slab.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/completion.h>
  14 #include <linux/buffer_head.h>
  15 #include <linux/pagemap.h>
  16 #include <linux/mpage.h>
  17 #include <linux/fs.h>
  18 #include <asm/semaphore.h>
  19
  20 #include "gfs2.h"
  21 #include "bmap.h"
  22 #include "glock.h"
  23 #include "inode.h"
  24 #include "log.h"
  25 #include "meta_io.h"
  26 #include "ops_address.h"
  27 #include "page.h"
  28 #include "quota.h"
  29 #include "trans.h"
  30 #include "rgrp.h"
  31 #include "ops_file.h"
  32
  33 /**
  34  * gfs2_get_block - Fills in a buffer head with details about a block
  35  * @inode: The inode
  36  * @lblock: The block number to look up
  37  * @bh_result: The buffer head to return the result in
  38  * @create: Non-zero if we may add block to the file
  39  *
  40  * Returns: errno
  41  */
  42
  43 int gfs2_get_block(struct inode *inode, sector_t lblock,
  44                    struct buffer_head *bh_result, int create)
  45 {
  46         struct gfs2_inode *ip = get_v2ip(inode);
  47         int new = create;
  48         uint64_t dblock;
  49         int error;
  50
  51         error = gfs2_block_map(ip, lblock, &new, &dblock, NULL);
  52         if (error)
  53                 return error;
  54
  55         if (!dblock)
  56                 return 0;
  57
  58         map_bh(bh_result, inode->i_sb, dblock);
  59         if (new)
  60                 set_buffer_new(bh_result);
  61
  62         return 0;
  63 }
  64
  65 /**
  66  * get_block_noalloc - Fills in a buffer head with details about a block
  67  * @inode: The inode
  68  * @lblock: The block number to look up
  69  * @bh_result: The buffer head to return the result in
  70  * @create: Non-zero if we may add block to the file
  71  *
  72  * Returns: errno
  73  */
  74
  75 static int get_block_noalloc(struct inode *inode, sector_t lblock,
  76                              struct buffer_head *bh_result, int create)
  77 {
  78         struct gfs2_inode *ip = get_v2ip(inode);
  79         int new = 0;
  80         uint64_t dblock;
  81         int error;
  82
  83         error = gfs2_block_map(ip, lblock, &new, &dblock, NULL);
  84         if (error)
  85                 return error;
  86
  87         if (dblock)
  88                 map_bh(bh_result, inode->i_sb, dblock);
  89         else if (gfs2_assert_withdraw(ip->i_sbd, !create))
  90                 error = -EIO;
  91
  92         return error;
  93 }
  94
  95 static int get_blocks(struct inode *inode, sector_t lblock,
  96                       unsigned long max_blocks, struct buffer_head *bh_result,
  97                       int create)
  98 {
  99         struct gfs2_inode *ip = get_v2ip(inode);
 100         int new = create;
 101         uint64_t dblock;
 102         uint32_t extlen;
 103         int error;
 104
 105         error = gfs2_block_map(ip, lblock, &new, &dblock, &extlen);
 106         if (error)
 107                 return error;
 108
 109         if (!dblock)
 110                 return 0;
 111
 112         map_bh(bh_result, inode->i_sb, dblock);
 113         if (new)
 114                 set_buffer_new(bh_result);
 115
 116         if (extlen > max_blocks)
 117                 extlen = max_blocks;
 118         bh_result->b_size = extlen << inode->i_blkbits;
 119
 120         return 0;
 121 }
 122
 123 static int get_blocks_noalloc(struct inode *inode, sector_t lblock,
 124                               unsigned long max_blocks,
 125                               struct buffer_head *bh_result, int create)
 126 {
 127         struct gfs2_inode *ip = get_v2ip(inode);
 128         int new = 0;
 129         uint64_t dblock;
 130         uint32_t extlen;
 131         int error;
 132
 133         error = gfs2_block_map(ip, lblock, &new, &dblock, &extlen);
 134         if (error)
 135                 return error;
 136
 137         if (dblock) {
 138                 map_bh(bh_result, inode->i_sb, dblock);
 139                 if (extlen > max_blocks)
 140                         extlen = max_blocks;
 141                 bh_result->b_size = extlen << inode->i_blkbits;
 142         } else if (gfs2_assert_withdraw(ip->i_sbd, !create))
 143                 error = -EIO;
 144
 145         return error;
 146 }
 147
 148 /**
 149  * gfs2_writepage - Write complete page
 150  * @page: Page to write
 151  *
 152  * Returns: errno
 153  *
 154  * Some of this is copied from block_write_full_page() although we still
 155  * call it to do most of the work.
 156  */
 157
 158 static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
 159 {
 160         struct inode *inode = page->mapping->host;
 161         struct gfs2_inode *ip = get_v2ip(page->mapping->host);
 162         struct gfs2_sbd *sdp = ip->i_sbd;
 163         loff_t i_size = i_size_read(inode);
 164         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 165         unsigned offset;
 166         int error;
 167         int done_trans = 0;
 168
 169         atomic_inc(&sdp->sd_ops_address);
 170         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) {
 171                 unlock_page(page);
 172                 return -EIO;
 173         }
 174         if (get_transaction)
 175                 goto out_ignore;
 176
 177         /* Is the page fully outside i_size? (truncate in progress) */
 178         offset = i_size & (PAGE_CACHE_SIZE-1);
 179         if (page->index >= end_index+1 || !offset) {
 180                 page->mapping->a_ops->invalidatepage(page, 0);
 181                 unlock_page(page);
 182                 return 0; /* don't care */
 183         }
 184
 185         if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip)) {
 186                 error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
 187                 if (error)
 188                         goto out_ignore;
 189                 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
 190                 done_trans = 1;
 191         }
 192
 193         error = block_write_full_page(page, get_block_noalloc, wbc);
 194         if (done_trans)
 195                 gfs2_trans_end(sdp);
 196         gfs2_meta_cache_flush(ip);
 197         return error;
 198
 199 out_ignore:
 200         redirty_page_for_writepage(wbc, page);
 201         unlock_page(page);
 202         return 0;
 203 }
 204
 205 /**
 206  * stuffed_readpage - Fill in a Linux page with stuffed file data
 207  * @ip: the inode
 208  * @page: the page
 209  *
 210  * Returns: errno
 211  */
 212
 213 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
 214 {
 215         struct buffer_head *dibh;
 216         void *kaddr;
 217         int error;
 218
 219         error = gfs2_meta_inode_buffer(ip, &dibh);
 220         if (error)
 221                 return error;
 222
 223         kaddr = kmap(page);
 224         memcpy((char *)kaddr,
 225                dibh->b_data + sizeof(struct gfs2_dinode),
 226                ip->i_di.di_size);
 227         memset((char *)kaddr + ip->i_di.di_size,
 228                0,
 229                PAGE_CACHE_SIZE - ip->i_di.di_size);
 230         kunmap(page);
 231
 232         brelse(dibh);
 233
 234         SetPageUptodate(page);
 235
 236         return 0;
 237 }
 238
 239 static int zero_readpage(struct page *page)
 240 {
 241         void *kaddr;
 242
 243         kaddr = kmap(page);
 244         memset(kaddr, 0, PAGE_CACHE_SIZE);
 245         kunmap(page);
 246
 247         SetPageUptodate(page);
 248         unlock_page(page);
 249
 250         return 0;
 251 }
 252
 253 /**
 254  * gfs2_readpage - readpage with locking
 255  * @file: The file to read a page for. N.B. This may be NULL if we are
 256  * reading an internal file.
 257  * @page: The page to read
 258  *
 259  * Returns: errno
 260  */
 261
 262 static int gfs2_readpage(struct file *file, struct page *page)
 263 {
 264         struct gfs2_inode *ip = get_v2ip(page->mapping->host);
 265         struct gfs2_sbd *sdp = ip->i_sbd;
 266         struct gfs2_holder gh;
 267         int error;
 268
 269         atomic_inc(&sdp->sd_ops_address);
 270
 271         if (file != &gfs2_internal_file_sentinal) {
 272                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
 273                 error = gfs2_glock_nq_m_atime(1, &gh);
 274                 if (error)
 275                         goto out_unlock;
 276         }
 277
 278         if (gfs2_is_stuffed(ip)) {
 279                 if (!page->index) {
 280                         error = stuffed_readpage(ip, page);
 281                         unlock_page(page);
 282                 } else
 283                         error = zero_readpage(page);
 284         } else
 285                 error = mpage_readpage(page, gfs2_get_block);
 286
 287         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 288                 error = -EIO;
 289
 290         if (file != &gfs2_internal_file_sentinal) {
 291                 gfs2_glock_dq_m(1, &gh);
 292                 gfs2_holder_uninit(&gh);
 293         }
 294 out:
 295         return error;
 296 out_unlock:
 297         unlock_page(page);
 298         goto out;
 299 }
 300
 301 /**
 302  * gfs2_prepare_write - Prepare to write a page to a file
 303  * @file: The file to write to
 304  * @page: The page which is to be prepared for writing
 305  * @from: From (byte range within page)
 306  * @to: To (byte range within page)
 307  *
 308  * Returns: errno
 309  */
 310
 311 static int gfs2_prepare_write(struct file *file, struct page *page,
 312                               unsigned from, unsigned to)
 313 {
 314         struct gfs2_inode *ip = get_v2ip(page->mapping->host);
 315         struct gfs2_sbd *sdp = ip->i_sbd;
 316         unsigned int data_blocks, ind_blocks, rblocks;
 317         int alloc_required;
 318         int error = 0;
 319         loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + from;
 320         loff_t end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
 321         struct gfs2_alloc *al;
 322
 323         atomic_inc(&sdp->sd_ops_address);
 324
 325         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME, &ip->i_gh);
 326         error = gfs2_glock_nq_m_atime(1, &ip->i_gh);
 327         if (error)
 328                 goto out_uninit;
 329
 330         gfs2_write_calc_reserv(ip, to - from, &data_blocks, &ind_blocks);
 331
 332         error = gfs2_write_alloc_required(ip, pos, from - to, &alloc_required);
 333         if (error)
 334                 goto out_unlock;
 335
 336
 337         if (alloc_required) {
 338                 al = gfs2_alloc_get(ip);
 339
 340                 error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
 341                 if (error)
 342                         goto out_alloc_put;
 343
 344                 error = gfs2_quota_check(ip, ip->i_di.di_uid, ip->i_di.di_gid);
 345                 if (error)
 346                         goto out_qunlock;
 347
 348                 al->al_requested = data_blocks + ind_blocks;
 349                 error = gfs2_inplace_reserve(ip);
 350                 if (error)
 351                         goto out_qunlock;
 352         }
 353
 354         rblocks = RES_DINODE + ind_blocks;
 355         if (gfs2_is_jdata(ip))
 356                 rblocks += data_blocks ? data_blocks : 1;
 357         if (ind_blocks || data_blocks)
 358                 rblocks += RES_STATFS + RES_QUOTA;
 359
 360         error = gfs2_trans_begin(sdp, rblocks, 0);
 361         if (error)
 362                 goto out;
 363
 364         if (gfs2_is_stuffed(ip)) {
 365                 if (end > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
 366                         error = gfs2_unstuff_dinode(ip, gfs2_unstuffer_page, page);
 367                         if (error)
 368                                 goto out;
 369                 } else if (!PageUptodate(page)) {
 370                         error = stuffed_readpage(ip, page);
 371                         goto out;
 372                 }
 373         }
 374
 375         error = block_prepare_write(page, from, to, gfs2_get_block);
 376
 377 out:
 378         if (error) {
 379                 gfs2_trans_end(sdp);
 380                 if (alloc_required) {
 381                         gfs2_inplace_release(ip);
 382 out_qunlock:
 383                         gfs2_quota_unlock(ip);
 384 out_alloc_put:
 385                         gfs2_alloc_put(ip);
 386                 }
 387 out_unlock:
 388                 gfs2_glock_dq_m(1, &ip->i_gh);
 389 out_uninit:
 390                 gfs2_holder_uninit(&ip->i_gh);
 391         }
 392
 393         return error;
 394 }
 395
 396 /**
 397  * gfs2_commit_write - Commit write to a file
 398  * @file: The file to write to
 399  * @page: The page containing the data
 400  * @from: From (byte range within page)
 401  * @to: To (byte range within page)
 402  *
 403  * Returns: errno
 404  */
 405
 406 static int gfs2_commit_write(struct file *file, struct page *page,
 407                              unsigned from, unsigned to)
 408 {
 409         struct inode *inode = page->mapping->host;
 410         struct gfs2_inode *ip = get_v2ip(inode);
 411         struct gfs2_sbd *sdp = ip->i_sbd;
 412         int error = -EOPNOTSUPP;
 413         struct buffer_head *dibh;
 414         struct gfs2_alloc *al = &ip->i_alloc;;
 415
 416         atomic_inc(&sdp->sd_ops_address);
 417
 418
 419         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)))
 420                 goto fail_nounlock;
 421
 422         error = gfs2_meta_inode_buffer(ip, &dibh);
 423         if (error)
 424                 goto fail_endtrans;
 425
 426         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 427
 428         if (gfs2_is_stuffed(ip)) {
 429                 uint64_t file_size;
 430                 void *kaddr;
 431
 432                 file_size = ((uint64_t)page->index << PAGE_CACHE_SHIFT) + to;
 433
 434                 kaddr = kmap_atomic(page, KM_USER0);
 435                 memcpy(dibh->b_data + sizeof(struct gfs2_dinode) + from,
 436                        (char *)kaddr + from, to - from);
 437                 kunmap_atomic(page, KM_USER0);
 438
 439                 SetPageUptodate(page);
 440
 441                 if (inode->i_size < file_size)
 442                         i_size_write(inode, file_size);
 443         } else {
 444                 if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip))
 445                         gfs2_page_add_databufs(ip, page, from, to);
 446                 error = generic_commit_write(file, page, from, to);
 447                 if (error)
 448                         goto fail;
 449         }
 450
 451         if (ip->i_di.di_size < inode->i_size)
 452                 ip->i_di.di_size = inode->i_size;
 453
 454         gfs2_dinode_out(&ip->i_di, dibh->b_data);
 455         brelse(dibh);
 456         gfs2_trans_end(sdp);
 457         if (al->al_requested) {
 458                 gfs2_inplace_release(ip);
 459                 gfs2_quota_unlock(ip);
 460                 gfs2_alloc_put(ip);
 461         }
 462         gfs2_glock_dq_m(1, &ip->i_gh);
 463         gfs2_holder_uninit(&ip->i_gh);
 464         return 0;
 465
 466 fail:
 467         brelse(dibh);
 468 fail_endtrans:
 469         gfs2_trans_end(sdp);
 470         if (al->al_requested) {
 471                 gfs2_inplace_release(ip);
 472                 gfs2_quota_unlock(ip);
 473                 gfs2_alloc_put(ip);
 474         }
 475         gfs2_glock_dq_m(1, &ip->i_gh);
 476         gfs2_holder_uninit(&ip->i_gh);
 477 fail_nounlock:
 478         ClearPageUptodate(page);
 479         return error;
 480 }
 481
 482 /**
 483  * gfs2_bmap - Block map function
 484  * @mapping: Address space info
 485  * @lblock: The block to map
 486  *
 487  * Returns: The disk address for the block or 0 on hole or error
 488  */
 489
 490 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
 491 {
 492         struct gfs2_inode *ip = get_v2ip(mapping->host);
 493         struct gfs2_holder i_gh;
 494         sector_t dblock = 0;
 495         int error;
 496
 497         atomic_inc(&ip->i_sbd->sd_ops_address);
 498
 499         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 500         if (error)
 501                 return 0;
 502
 503         if (!gfs2_is_stuffed(ip))
 504                 dblock = generic_block_bmap(mapping, lblock, gfs2_get_block);
 505
 506         gfs2_glock_dq_uninit(&i_gh);
 507
 508         return dblock;
 509 }
 510
 511 static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
 512 {
 513         struct gfs2_bufdata *bd;
 514
 515         gfs2_log_lock(sdp);
 516         bd = get_v2bd(bh);
 517         if (bd) {
 518                 bd->bd_bh = NULL;
 519                 set_v2bd(bh, NULL);
 520                 gfs2_log_unlock(sdp);
 521                 brelse(bh);
 522         } else
 523                 gfs2_log_unlock(sdp);
 524
 525         lock_buffer(bh);
 526         clear_buffer_dirty(bh);
 527         bh->b_bdev = NULL;
 528         clear_buffer_mapped(bh);
 529         clear_buffer_req(bh);
 530         clear_buffer_new(bh);
 531         clear_buffer_delay(bh);
 532         unlock_buffer(bh);
 533 }
 534
 535 static int gfs2_invalidatepage(struct page *page, unsigned long offset)
 536 {
 537         struct gfs2_sbd *sdp = get_v2sdp(page->mapping->host->i_sb);
 538         struct buffer_head *head, *bh, *next;
 539         unsigned int curr_off = 0;
 540         int ret = 1;
 541
 542         BUG_ON(!PageLocked(page));
 543         if (!page_has_buffers(page))
 544                 return 1;
 545
 546         bh = head = page_buffers(page);
 547         do {
 548                 unsigned int next_off = curr_off + bh->b_size;
 549                 next = bh->b_this_page;
 550
 551                 if (offset <= curr_off)
 552                         discard_buffer(sdp, bh);
 553
 554                 curr_off = next_off;
 555                 bh = next;
 556         } while (bh != head);
 557
 558         if (!offset)
 559                 ret = try_to_release_page(page, 0);
 560
 561         return ret;
 562 }
 563
 564 static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov,
 565                                     loff_t offset, unsigned long nr_segs)
 566 {
 567         struct file *file = iocb->ki_filp;
 568         struct inode *inode = file->f_mapping->host;
 569         struct gfs2_inode *ip = get_v2ip(inode);
 570         struct gfs2_holder gh;
 571         int rv;
 572
 573         /*
 574          * Shared lock, even though its write, since we do no allocation
 575          * on this path. All we need change is atime.
 576          */
 577         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
 578         rv = gfs2_glock_nq_m_atime(1, &gh);
 579         if (rv)
 580                 goto out;
 581
 582         /*
 583          * Should we return an error here? I can't see that O_DIRECT for
 584          * a journaled file makes any sense. For now we'll silently fall
 585          * back to buffered I/O, likewise we do the same for stuffed
 586          * files since they are (a) small and (b) unaligned.
 587          */
 588         if (gfs2_is_jdata(ip))
 589                 goto out;
 590
 591         if (gfs2_is_stuffed(ip))
 592                 goto out;
 593
 594         rv = __blockdev_direct_IO(WRITE, iocb, inode, inode->i_sb->s_bdev,
 595                                   iov, offset, nr_segs, get_blocks_noalloc,
 596                                   NULL, DIO_OWN_LOCKING);
 597 out:
 598         gfs2_glock_dq_m(1, &gh);
 599         gfs2_holder_uninit(&gh);
 600
 601         return rv;
 602 }
 603
 604 /**
 605  * gfs2_direct_IO
 606  *
 607  * This is called with a shared lock already held for the read path.
 608  * Currently, no locks are held when the write path is called.
 609  */
 610 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 611                               const struct iovec *iov, loff_t offset,
 612                               unsigned long nr_segs)
 613 {
 614         struct file *file = iocb->ki_filp;
 615         struct inode *inode = file->f_mapping->host;
 616         struct gfs2_inode *ip = get_v2ip(inode);
 617         struct gfs2_sbd *sdp = ip->i_sbd;
 618
 619         atomic_inc(&sdp->sd_ops_address);
 620
 621         if (rw == WRITE)
 622                 return gfs2_direct_IO_write(iocb, iov, offset, nr_segs);
 623
 624         if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)) ||
 625             gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip)))
 626                 return -EINVAL;
 627
 628         return __blockdev_direct_IO(READ, iocb, inode, inode->i_sb->s_bdev, iov,
 629                                     offset, nr_segs, get_blocks, NULL,
 630                                     DIO_OWN_LOCKING);
 631 }
 632
 633 struct address_space_operations gfs2_file_aops = {
 634         .writepage = gfs2_writepage,
 635         .readpage = gfs2_readpage,
 636         .sync_page = block_sync_page,
 637         .prepare_write = gfs2_prepare_write,
 638         .commit_write = gfs2_commit_write,
 639         .bmap = gfs2_bmap,
 640         .invalidatepage = gfs2_invalidatepage,
 641         .direct_IO = gfs2_direct_IO,
 642 };
 643