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 <linux/gfs2_ondisk.h>
  19 #include <asm/semaphore.h>
  20
  21 #include "gfs2.h"
  22 #include "lm_interface.h"
  23 #include "incore.h"
  24 #include "bmap.h"
  25 #include "glock.h"
  26 #include "inode.h"
  27 #include "log.h"
  28 #include "meta_io.h"
  29 #include "ops_address.h"
  30 #include "page.h"
  31 #include "quota.h"
  32 #include "trans.h"
  33 #include "rgrp.h"
  34 #include "ops_file.h"
  35 #include "util.h"
  36
  37 /**
  38  * gfs2_get_block - Fills in a buffer head with details about a block
  39  * @inode: The inode
  40  * @lblock: The block number to look up
  41  * @bh_result: The buffer head to return the result in
  42  * @create: Non-zero if we may add block to the file
  43  *
  44  * Returns: errno
  45  */
  46
  47 int gfs2_get_block(struct inode *inode, sector_t lblock,
  48                    struct buffer_head *bh_result, int create)
  49 {
  50         struct gfs2_inode *ip = inode->u.generic_ip;
  51         int new = create;
  52         uint64_t dblock;
  53         int error;
  54
  55         error = gfs2_block_map(ip, lblock, &new, &dblock, NULL);
  56         if (error)
  57                 return error;
  58
  59         if (!dblock)
  60                 return 0;
  61
  62         map_bh(bh_result, inode->i_sb, dblock);
  63         if (new)
  64                 set_buffer_new(bh_result);
  65
  66         return 0;
  67 }
  68
  69 /**
  70  * get_block_noalloc - Fills in a buffer head with details about a block
  71  * @inode: The inode
  72  * @lblock: The block number to look up
  73  * @bh_result: The buffer head to return the result in
  74  * @create: Non-zero if we may add block to the file
  75  *
  76  * Returns: errno
  77  */
  78
  79 static int get_block_noalloc(struct inode *inode, sector_t lblock,
  80                              struct buffer_head *bh_result, int create)
  81 {
  82         struct gfs2_inode *ip = inode->u.generic_ip;
  83         int new = 0;
  84         uint64_t dblock;
  85         int error;
  86
  87         error = gfs2_block_map(ip, lblock, &new, &dblock, NULL);
  88         if (error)
  89                 return error;
  90
  91         if (dblock)
  92                 map_bh(bh_result, inode->i_sb, dblock);
  93         else if (gfs2_assert_withdraw(ip->i_sbd, !create))
  94                 error = -EIO;
  95
  96         return error;
  97 }
  98
  99 static int get_blocks(struct inode *inode, sector_t lblock,
 100                       unsigned long max_blocks, struct buffer_head *bh_result,
 101                       int create)
 102 {
 103         struct gfs2_inode *ip = inode->u.generic_ip;
 104         int new = create;
 105         uint64_t dblock;
 106         uint32_t extlen;
 107         int error;
 108
 109         error = gfs2_block_map(ip, lblock, &new, &dblock, &extlen);
 110         if (error)
 111                 return error;
 112
 113         if (!dblock)
 114                 return 0;
 115
 116         map_bh(bh_result, inode->i_sb, dblock);
 117         if (new)
 118                 set_buffer_new(bh_result);
 119
 120         if (extlen > max_blocks)
 121                 extlen = max_blocks;
 122         bh_result->b_size = extlen << inode->i_blkbits;
 123
 124         return 0;
 125 }
 126
 127 static int get_blocks_noalloc(struct inode *inode, sector_t lblock,
 128                               unsigned long max_blocks,
 129                               struct buffer_head *bh_result, int create)
 130 {
 131         struct gfs2_inode *ip = inode->u.generic_ip;
 132         int new = 0;
 133         uint64_t dblock;
 134         uint32_t extlen;
 135         int error;
 136
 137         error = gfs2_block_map(ip, lblock, &new, &dblock, &extlen);
 138         if (error)
 139                 return error;
 140
 141         if (dblock) {
 142                 map_bh(bh_result, inode->i_sb, dblock);
 143                 if (extlen > max_blocks)
 144                         extlen = max_blocks;
 145                 bh_result->b_size = extlen << inode->i_blkbits;
 146         } else if (gfs2_assert_withdraw(ip->i_sbd, !create))
 147                 error = -EIO;
 148
 149         return error;
 150 }
 151
 152 /**
 153  * gfs2_writepage - Write complete page
 154  * @page: Page to write
 155  *
 156  * Returns: errno
 157  *
 158  * Some of this is copied from block_write_full_page() although we still
 159  * call it to do most of the work.
 160  */
 161
 162 static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
 163 {
 164         struct inode *inode = page->mapping->host;
 165         struct gfs2_inode *ip = page->mapping->host->u.generic_ip;
 166         struct gfs2_sbd *sdp = ip->i_sbd;
 167         loff_t i_size = i_size_read(inode);
 168         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 169         unsigned offset;
 170         int error;
 171         int done_trans = 0;
 172
 173         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) {
 174                 unlock_page(page);
 175                 return -EIO;
 176         }
 177         if (current->journal_info)
 178                 goto out_ignore;
 179
 180         /* Is the page fully outside i_size? (truncate in progress) */
 181         offset = i_size & (PAGE_CACHE_SIZE-1);
 182         if (page->index >= end_index+1 || !offset) {
 183                 page->mapping->a_ops->invalidatepage(page, 0);
 184                 unlock_page(page);
 185                 return 0; /* don't care */
 186         }
 187
 188         if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip)) {
 189                 error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
 190                 if (error)
 191                         goto out_ignore;
 192                 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
 193                 done_trans = 1;
 194         }
 195         error = block_write_full_page(page, get_block_noalloc, wbc);
 196         if (done_trans)
 197                 gfs2_trans_end(sdp);
 198         gfs2_meta_cache_flush(ip);
 199         return error;
 200
 201 out_ignore:
 202         redirty_page_for_writepage(wbc, page);
 203         unlock_page(page);
 204         return 0;
 205 }
 206
 207 /**
 208  * stuffed_readpage - Fill in a Linux page with stuffed file data
 209  * @ip: the inode
 210  * @page: the page
 211  *
 212  * Returns: errno
 213  */
 214
 215 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
 216 {
 217         struct buffer_head *dibh;
 218         void *kaddr;
 219         int error;
 220
 221         error = gfs2_meta_inode_buffer(ip, &dibh);
 222         if (error)
 223                 return error;
 224
 225         kaddr = kmap_atomic(page, KM_USER0);
 226         memcpy((char *)kaddr,
 227                dibh->b_data + sizeof(struct gfs2_dinode),
 228                ip->i_di.di_size);
 229         memset((char *)kaddr + ip->i_di.di_size,
 230                0,
 231                PAGE_CACHE_SIZE - ip->i_di.di_size);
 232         kunmap_atomic(page, KM_USER0);
 233
 234         brelse(dibh);
 235
 236         SetPageUptodate(page);
 237
 238         return 0;
 239 }
 240
 241 static int zero_readpage(struct page *page)
 242 {
 243         void *kaddr;
 244
 245         kaddr = kmap_atomic(page, KM_USER0);
 246         memset(kaddr, 0, PAGE_CACHE_SIZE);
 247         kunmap_atomic(page, KM_USER0);
 248
 249         SetPageUptodate(page);
 250         unlock_page(page);
 251
 252         return 0;
 253 }
 254
 255 /**
 256  * gfs2_readpage - readpage with locking
 257  * @file: The file to read a page for. N.B. This may be NULL if we are
 258  * reading an internal file.
 259  * @page: The page to read
 260  *
 261  * Returns: errno
 262  */
 263
 264 static int gfs2_readpage(struct file *file, struct page *page)
 265 {
 266         struct gfs2_inode *ip = page->mapping->host->u.generic_ip;
 267         struct gfs2_sbd *sdp = ip->i_sbd;
 268         struct gfs2_holder gh;
 269         int error;
 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 = page->mapping->host->u.generic_ip;
 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         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME, &ip->i_gh);
 324         error = gfs2_glock_nq_m_atime(1, &ip->i_gh);
 325         if (error)
 326                 goto out_uninit;
 327
 328         gfs2_write_calc_reserv(ip, to - from, &data_blocks, &ind_blocks);
 329
 330         error = gfs2_write_alloc_required(ip, pos, from - to, &alloc_required);
 331         if (error)
 332                 goto out_unlock;
 333
 334
 335         if (alloc_required) {
 336                 al = gfs2_alloc_get(ip);
 337
 338                 error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
 339                 if (error)
 340                         goto out_alloc_put;
 341
 342                 error = gfs2_quota_check(ip, ip->i_di.di_uid, ip->i_di.di_gid);
 343                 if (error)
 344                         goto out_qunlock;
 345
 346                 al->al_requested = data_blocks + ind_blocks;
 347                 error = gfs2_inplace_reserve(ip);
 348                 if (error)
 349                         goto out_qunlock;
 350         }
 351
 352         rblocks = RES_DINODE + ind_blocks;
 353         if (gfs2_is_jdata(ip))
 354                 rblocks += data_blocks ? data_blocks : 1;
 355         if (ind_blocks || data_blocks)
 356                 rblocks += RES_STATFS + RES_QUOTA;
 357
 358         error = gfs2_trans_begin(sdp, rblocks, 0);
 359         if (error)
 360                 goto out;
 361
 362         if (gfs2_is_stuffed(ip)) {
 363                 if (end > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
 364                         error = gfs2_unstuff_dinode(ip, gfs2_unstuffer_page,
 365                                                     page);
 366                         if (error == 0)
 367                                 goto prepare_write;
 368                 } else if (!PageUptodate(page))
 369                         error = stuffed_readpage(ip, page);
 370                 goto out;
 371         }
 372
 373 prepare_write:
 374         error = block_prepare_write(page, from, to, gfs2_get_block);
 375
 376 out:
 377         if (error) {
 378                 gfs2_trans_end(sdp);
 379                 if (alloc_required) {
 380                         gfs2_inplace_release(ip);
 381 out_qunlock:
 382                         gfs2_quota_unlock(ip);
 383 out_alloc_put:
 384                         gfs2_alloc_put(ip);
 385                 }
 386 out_unlock:
 387                 gfs2_glock_dq_m(1, &ip->i_gh);
 388 out_uninit:
 389                 gfs2_holder_uninit(&ip->i_gh);
 390         }
 391
 392         return error;
 393 }
 394
 395 /**
 396  * gfs2_commit_write - Commit write to a file
 397  * @file: The file to write to
 398  * @page: The page containing the data
 399  * @from: From (byte range within page)
 400  * @to: To (byte range within page)
 401  *
 402  * Returns: errno
 403  */
 404
 405 static int gfs2_commit_write(struct file *file, struct page *page,
 406                              unsigned from, unsigned to)
 407 {
 408         struct inode *inode = page->mapping->host;
 409         struct gfs2_inode *ip = inode->u.generic_ip;
 410         struct gfs2_sbd *sdp = ip->i_sbd;
 411         int error = -EOPNOTSUPP;
 412         struct buffer_head *dibh;
 413         struct gfs2_alloc *al = &ip->i_alloc;;
 414
 415         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)))
 416                 goto fail_nounlock;
 417
 418         error = gfs2_meta_inode_buffer(ip, &dibh);
 419         if (error)
 420                 goto fail_endtrans;
 421
 422         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 423
 424         if (gfs2_is_stuffed(ip)) {
 425                 uint64_t file_size;
 426                 void *kaddr;
 427
 428                 file_size = ((uint64_t)page->index << PAGE_CACHE_SHIFT) + to;
 429
 430                 kaddr = kmap_atomic(page, KM_USER0);
 431                 memcpy(dibh->b_data + sizeof(struct gfs2_dinode) + from,
 432                        (char *)kaddr + from, to - from);
 433                 kunmap_atomic(page, KM_USER0);
 434
 435                 SetPageUptodate(page);
 436
 437                 if (inode->i_size < file_size)
 438                         i_size_write(inode, file_size);
 439         } else {
 440                 if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED ||
 441                     gfs2_is_jdata(ip))
 442                         gfs2_page_add_databufs(ip, page, from, to);
 443                 error = generic_commit_write(file, page, from, to);
 444                 if (error)
 445                         goto fail;
 446         }
 447
 448         if (ip->i_di.di_size < inode->i_size)
 449                 ip->i_di.di_size = inode->i_size;
 450
 451         gfs2_dinode_out(&ip->i_di, dibh->b_data);
 452         brelse(dibh);
 453         gfs2_trans_end(sdp);
 454         if (al->al_requested) {
 455                 gfs2_inplace_release(ip);
 456                 gfs2_quota_unlock(ip);
 457                 gfs2_alloc_put(ip);
 458         }
 459         gfs2_glock_dq_m(1, &ip->i_gh);
 460         gfs2_holder_uninit(&ip->i_gh);
 461         return 0;
 462
 463 fail:
 464         brelse(dibh);
 465 fail_endtrans:
 466         gfs2_trans_end(sdp);
 467         if (al->al_requested) {
 468                 gfs2_inplace_release(ip);
 469                 gfs2_quota_unlock(ip);
 470                 gfs2_alloc_put(ip);
 471         }
 472         gfs2_glock_dq_m(1, &ip->i_gh);
 473         gfs2_holder_uninit(&ip->i_gh);
 474 fail_nounlock:
 475         ClearPageUptodate(page);
 476         return error;
 477 }
 478
 479 /**
 480  * gfs2_bmap - Block map function
 481  * @mapping: Address space info
 482  * @lblock: The block to map
 483  *
 484  * Returns: The disk address for the block or 0 on hole or error
 485  */
 486
 487 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
 488 {
 489         struct gfs2_inode *ip = mapping->host->u.generic_ip;
 490         struct gfs2_holder i_gh;
 491         sector_t dblock = 0;
 492         int error;
 493
 494         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 495         if (error)
 496                 return 0;
 497
 498         if (!gfs2_is_stuffed(ip))
 499                 dblock = generic_block_bmap(mapping, lblock, gfs2_get_block);
 500
 501         gfs2_glock_dq_uninit(&i_gh);
 502
 503         return dblock;
 504 }
 505
 506 static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
 507 {
 508         struct gfs2_bufdata *bd;
 509
 510         gfs2_log_lock(sdp);
 511         bd = bh->b_private;
 512         if (bd) {
 513                 bd->bd_bh = NULL;
 514                 bh->b_private = NULL;
 515                 gfs2_log_unlock(sdp);
 516                 brelse(bh);
 517         } else
 518                 gfs2_log_unlock(sdp);
 519
 520         lock_buffer(bh);
 521         clear_buffer_dirty(bh);
 522         bh->b_bdev = NULL;
 523         clear_buffer_mapped(bh);
 524         clear_buffer_req(bh);
 525         clear_buffer_new(bh);
 526         clear_buffer_delay(bh);
 527         unlock_buffer(bh);
 528 }
 529
 530 static int gfs2_invalidatepage(struct page *page, unsigned long offset)
 531 {
 532         struct gfs2_sbd *sdp = page->mapping->host->i_sb->s_fs_info;
 533         struct buffer_head *head, *bh, *next;
 534         unsigned int curr_off = 0;
 535         int ret = 1;
 536
 537         BUG_ON(!PageLocked(page));
 538         if (!page_has_buffers(page))
 539                 return 1;
 540
 541         bh = head = page_buffers(page);
 542         do {
 543                 unsigned int next_off = curr_off + bh->b_size;
 544                 next = bh->b_this_page;
 545
 546                 if (offset <= curr_off)
 547                         discard_buffer(sdp, bh);
 548
 549                 curr_off = next_off;
 550                 bh = next;
 551         } while (bh != head);
 552
 553         if (!offset)
 554                 ret = try_to_release_page(page, 0);
 555
 556         return ret;
 557 }
 558
 559 static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov,
 560                                     loff_t offset, unsigned long nr_segs)
 561 {
 562         struct file *file = iocb->ki_filp;
 563         struct inode *inode = file->f_mapping->host;
 564         struct gfs2_inode *ip = inode->u.generic_ip;
 565         struct gfs2_holder gh;
 566         int rv;
 567
 568         /*
 569          * Shared lock, even though its write, since we do no allocation
 570          * on this path. All we need change is atime.
 571          */
 572         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
 573         rv = gfs2_glock_nq_m_atime(1, &gh);
 574         if (rv)
 575                 goto out;
 576
 577         /*
 578          * Should we return an error here? I can't see that O_DIRECT for
 579          * a journaled file makes any sense. For now we'll silently fall
 580          * back to buffered I/O, likewise we do the same for stuffed
 581          * files since they are (a) small and (b) unaligned.
 582          */
 583         if (gfs2_is_jdata(ip))
 584                 goto out;
 585
 586         if (gfs2_is_stuffed(ip))
 587                 goto out;
 588
 589         rv = __blockdev_direct_IO(WRITE, iocb, inode, inode->i_sb->s_bdev,
 590                                   iov, offset, nr_segs, get_blocks_noalloc,
 591                                   NULL, DIO_OWN_LOCKING);
 592 out:
 593         gfs2_glock_dq_m(1, &gh);
 594         gfs2_holder_uninit(&gh);
 595
 596         return rv;
 597 }
 598
 599 /**
 600  * gfs2_direct_IO
 601  *
 602  * This is called with a shared lock already held for the read path.
 603  * Currently, no locks are held when the write path is called.
 604  */
 605 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 606                               const struct iovec *iov, loff_t offset,
 607                               unsigned long nr_segs)
 608 {
 609         struct file *file = iocb->ki_filp;
 610         struct inode *inode = file->f_mapping->host;
 611         struct gfs2_inode *ip = inode->u.generic_ip;
 612         struct gfs2_sbd *sdp = ip->i_sbd;
 613
 614         if (rw == WRITE)
 615                 return gfs2_direct_IO_write(iocb, iov, offset, nr_segs);
 616
 617         if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)) ||
 618             gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip)))
 619                 return -EINVAL;
 620
 621         return __blockdev_direct_IO(READ, iocb, inode, inode->i_sb->s_bdev, iov,
 622                                     offset, nr_segs, get_blocks, NULL,
 623                                     DIO_OWN_LOCKING);
 624 }
 625
 626 struct address_space_operations gfs2_file_aops = {
 627         .writepage = gfs2_writepage,
 628         .readpage = gfs2_readpage,
 629         .sync_page = block_sync_page,
 630         .prepare_write = gfs2_prepare_write,
 631         .commit_write = gfs2_commit_write,
 632         .bmap = gfs2_bmap,
 633         .invalidatepage = gfs2_invalidatepage,
 634         .direct_IO = gfs2_direct_IO,
 635 };
 636