git.oblomov.eu 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 /**
 100  * gfs2_writepage - Write complete page
 101  * @page: Page to write
 102  *
 103  * Returns: errno
 104  *
 105  * Some of this is copied from block_write_full_page() although we still
 106  * call it to do most of the work.
 107  */
 108
 109 static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
 110 {
 111         struct inode *inode = page->mapping->host;
 112         struct gfs2_inode *ip = page->mapping->host->u.generic_ip;
 113         struct gfs2_sbd *sdp = ip->i_sbd;
 114         loff_t i_size = i_size_read(inode);
 115         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 116         unsigned offset;
 117         int error;
 118         int done_trans = 0;
 119
 120         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) {
 121                 unlock_page(page);
 122                 return -EIO;
 123         }
 124         if (current->journal_info)
 125                 goto out_ignore;
 126
 127         /* Is the page fully outside i_size? (truncate in progress) */
 128         offset = i_size & (PAGE_CACHE_SIZE-1);
 129         if (page->index >= end_index+1 || !offset) {
 130                 page->mapping->a_ops->invalidatepage(page, 0);
 131                 unlock_page(page);
 132                 return 0; /* don't care */
 133         }
 134
 135         if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip)) {
 136                 error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
 137                 if (error)
 138                         goto out_ignore;
 139                 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
 140                 done_trans = 1;
 141         }
 142         error = block_write_full_page(page, get_block_noalloc, wbc);
 143         if (done_trans)
 144                 gfs2_trans_end(sdp);
 145         gfs2_meta_cache_flush(ip);
 146         return error;
 147
 148 out_ignore:
 149         redirty_page_for_writepage(wbc, page);
 150         unlock_page(page);
 151         return 0;
 152 }
 153
 154 /**
 155  * stuffed_readpage - Fill in a Linux page with stuffed file data
 156  * @ip: the inode
 157  * @page: the page
 158  *
 159  * Returns: errno
 160  */
 161
 162 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
 163 {
 164         struct buffer_head *dibh;
 165         void *kaddr;
 166         int error;
 167
 168         error = gfs2_meta_inode_buffer(ip, &dibh);
 169         if (error)
 170                 return error;
 171
 172         kaddr = kmap_atomic(page, KM_USER0);
 173         memcpy((char *)kaddr,
 174                dibh->b_data + sizeof(struct gfs2_dinode),
 175                ip->i_di.di_size);
 176         memset((char *)kaddr + ip->i_di.di_size,
 177                0,
 178                PAGE_CACHE_SIZE - ip->i_di.di_size);
 179         kunmap_atomic(page, KM_USER0);
 180
 181         brelse(dibh);
 182
 183         SetPageUptodate(page);
 184
 185         return 0;
 186 }
 187
 188 static int zero_readpage(struct page *page)
 189 {
 190         void *kaddr;
 191
 192         kaddr = kmap_atomic(page, KM_USER0);
 193         memset(kaddr, 0, PAGE_CACHE_SIZE);
 194         kunmap_atomic(page, KM_USER0);
 195
 196         SetPageUptodate(page);
 197         unlock_page(page);
 198
 199         return 0;
 200 }
 201
 202 /**
 203  * gfs2_readpage - readpage with locking
 204  * @file: The file to read a page for. N.B. This may be NULL if we are
 205  * reading an internal file.
 206  * @page: The page to read
 207  *
 208  * Returns: errno
 209  */
 210
 211 static int gfs2_readpage(struct file *file, struct page *page)
 212 {
 213         struct gfs2_inode *ip = page->mapping->host->u.generic_ip;
 214         struct gfs2_sbd *sdp = ip->i_sbd;
 215         struct gfs2_holder gh;
 216         int error;
 217
 218         if (file != &gfs2_internal_file_sentinal) {
 219                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|GL_AOP, &gh);
 220                 error = gfs2_glock_nq_m_atime(1, &gh);
 221                 if (error)
 222                         goto out_unlock;
 223         }
 224
 225         if (gfs2_is_stuffed(ip)) {
 226                 if (!page->index) {
 227                         error = stuffed_readpage(ip, page);
 228                         unlock_page(page);
 229                 } else
 230                         error = zero_readpage(page);
 231         } else
 232                 error = mpage_readpage(page, gfs2_get_block);
 233
 234         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 235                 error = -EIO;
 236
 237         if (file != &gfs2_internal_file_sentinal) {
 238                 gfs2_glock_dq_m(1, &gh);
 239                 gfs2_holder_uninit(&gh);
 240         }
 241 out:
 242         return error;
 243 out_unlock:
 244         unlock_page(page);
 245         goto out;
 246 }
 247
 248 /**
 249  * gfs2_prepare_write - Prepare to write a page to a file
 250  * @file: The file to write to
 251  * @page: The page which is to be prepared for writing
 252  * @from: From (byte range within page)
 253  * @to: To (byte range within page)
 254  *
 255  * Returns: errno
 256  */
 257
 258 static int gfs2_prepare_write(struct file *file, struct page *page,
 259                               unsigned from, unsigned to)
 260 {
 261         struct gfs2_inode *ip = page->mapping->host->u.generic_ip;
 262         struct gfs2_sbd *sdp = ip->i_sbd;
 263         unsigned int data_blocks, ind_blocks, rblocks;
 264         int alloc_required;
 265         int error = 0;
 266         loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + from;
 267         loff_t end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
 268         struct gfs2_alloc *al;
 269
 270         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|GL_AOP, &ip->i_gh);
 271         error = gfs2_glock_nq_m_atime(1, &ip->i_gh);
 272         if (error)
 273                 goto out_uninit;
 274
 275         gfs2_write_calc_reserv(ip, to - from, &data_blocks, &ind_blocks);
 276
 277         error = gfs2_write_alloc_required(ip, pos, from - to, &alloc_required);
 278         if (error)
 279                 goto out_unlock;
 280
 281
 282         if (alloc_required) {
 283                 al = gfs2_alloc_get(ip);
 284
 285                 error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
 286                 if (error)
 287                         goto out_alloc_put;
 288
 289                 error = gfs2_quota_check(ip, ip->i_di.di_uid, ip->i_di.di_gid);
 290                 if (error)
 291                         goto out_qunlock;
 292
 293                 al->al_requested = data_blocks + ind_blocks;
 294                 error = gfs2_inplace_reserve(ip);
 295                 if (error)
 296                         goto out_qunlock;
 297         }
 298
 299         rblocks = RES_DINODE + ind_blocks;
 300         if (gfs2_is_jdata(ip))
 301                 rblocks += data_blocks ? data_blocks : 1;
 302         if (ind_blocks || data_blocks)
 303                 rblocks += RES_STATFS + RES_QUOTA;
 304
 305         error = gfs2_trans_begin(sdp, rblocks, 0);
 306         if (error)
 307                 goto out;
 308
 309         if (gfs2_is_stuffed(ip)) {
 310                 if (end > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
 311                         error = gfs2_unstuff_dinode(ip, gfs2_unstuffer_page,
 312                                                     page);
 313                         if (error == 0)
 314                                 goto prepare_write;
 315                 } else if (!PageUptodate(page))
 316                         error = stuffed_readpage(ip, page);
 317                 goto out;
 318         }
 319
 320 prepare_write:
 321         error = block_prepare_write(page, from, to, gfs2_get_block);
 322
 323 out:
 324         if (error) {
 325                 gfs2_trans_end(sdp);
 326                 if (alloc_required) {
 327                         gfs2_inplace_release(ip);
 328 out_qunlock:
 329                         gfs2_quota_unlock(ip);
 330 out_alloc_put:
 331                         gfs2_alloc_put(ip);
 332                 }
 333 out_unlock:
 334                 gfs2_glock_dq_m(1, &ip->i_gh);
 335 out_uninit:
 336                 gfs2_holder_uninit(&ip->i_gh);
 337         }
 338
 339         return error;
 340 }
 341
 342 /**
 343  * gfs2_commit_write - Commit write to a file
 344  * @file: The file to write to
 345  * @page: The page containing the data
 346  * @from: From (byte range within page)
 347  * @to: To (byte range within page)
 348  *
 349  * Returns: errno
 350  */
 351
 352 static int gfs2_commit_write(struct file *file, struct page *page,
 353                              unsigned from, unsigned to)
 354 {
 355         struct inode *inode = page->mapping->host;
 356         struct gfs2_inode *ip = inode->u.generic_ip;
 357         struct gfs2_sbd *sdp = ip->i_sbd;
 358         int error = -EOPNOTSUPP;
 359         struct buffer_head *dibh;
 360         struct gfs2_alloc *al = &ip->i_alloc;;
 361
 362         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)))
 363                 goto fail_nounlock;
 364
 365         error = gfs2_meta_inode_buffer(ip, &dibh);
 366         if (error)
 367                 goto fail_endtrans;
 368
 369         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 370
 371         if (gfs2_is_stuffed(ip)) {
 372                 uint64_t file_size;
 373                 void *kaddr;
 374
 375                 file_size = ((uint64_t)page->index << PAGE_CACHE_SHIFT) + to;
 376
 377                 kaddr = kmap_atomic(page, KM_USER0);
 378                 memcpy(dibh->b_data + sizeof(struct gfs2_dinode) + from,
 379                        (char *)kaddr + from, to - from);
 380                 kunmap_atomic(page, KM_USER0);
 381
 382                 SetPageUptodate(page);
 383
 384                 if (inode->i_size < file_size)
 385                         i_size_write(inode, file_size);
 386         } else {
 387                 if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED ||
 388                     gfs2_is_jdata(ip))
 389                         gfs2_page_add_databufs(ip, page, from, to);
 390                 error = generic_commit_write(file, page, from, to);
 391                 if (error)
 392                         goto fail;
 393         }
 394
 395         if (ip->i_di.di_size < inode->i_size)
 396                 ip->i_di.di_size = inode->i_size;
 397
 398         gfs2_dinode_out(&ip->i_di, dibh->b_data);
 399         brelse(dibh);
 400         gfs2_trans_end(sdp);
 401         if (al->al_requested) {
 402                 gfs2_inplace_release(ip);
 403                 gfs2_quota_unlock(ip);
 404                 gfs2_alloc_put(ip);
 405         }
 406         gfs2_glock_dq_m(1, &ip->i_gh);
 407         gfs2_holder_uninit(&ip->i_gh);
 408         return 0;
 409
 410 fail:
 411         brelse(dibh);
 412 fail_endtrans:
 413         gfs2_trans_end(sdp);
 414         if (al->al_requested) {
 415                 gfs2_inplace_release(ip);
 416                 gfs2_quota_unlock(ip);
 417                 gfs2_alloc_put(ip);
 418         }
 419         gfs2_glock_dq_m(1, &ip->i_gh);
 420         gfs2_holder_uninit(&ip->i_gh);
 421 fail_nounlock:
 422         ClearPageUptodate(page);
 423         return error;
 424 }
 425
 426 /**
 427  * gfs2_bmap - Block map function
 428  * @mapping: Address space info
 429  * @lblock: The block to map
 430  *
 431  * Returns: The disk address for the block or 0 on hole or error
 432  */
 433
 434 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
 435 {
 436         struct gfs2_inode *ip = mapping->host->u.generic_ip;
 437         struct gfs2_holder i_gh;
 438         sector_t dblock = 0;
 439         int error;
 440
 441         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 442         if (error)
 443                 return 0;
 444
 445         if (!gfs2_is_stuffed(ip))
 446                 dblock = generic_block_bmap(mapping, lblock, gfs2_get_block);
 447
 448         gfs2_glock_dq_uninit(&i_gh);
 449
 450         return dblock;
 451 }
 452
 453 static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
 454 {
 455         struct gfs2_bufdata *bd;
 456
 457         gfs2_log_lock(sdp);
 458         bd = bh->b_private;
 459         if (bd) {
 460                 bd->bd_bh = NULL;
 461                 bh->b_private = NULL;
 462                 gfs2_log_unlock(sdp);
 463                 brelse(bh);
 464         } else
 465                 gfs2_log_unlock(sdp);
 466
 467         lock_buffer(bh);
 468         clear_buffer_dirty(bh);
 469         bh->b_bdev = NULL;
 470         clear_buffer_mapped(bh);
 471         clear_buffer_req(bh);
 472         clear_buffer_new(bh);
 473         clear_buffer_delay(bh);
 474         unlock_buffer(bh);
 475 }
 476
 477 static void gfs2_invalidatepage(struct page *page, unsigned long offset)
 478 {
 479         struct gfs2_sbd *sdp = page->mapping->host->i_sb->s_fs_info;
 480         struct buffer_head *head, *bh, *next;
 481         unsigned int curr_off = 0;
 482
 483         BUG_ON(!PageLocked(page));
 484         if (!page_has_buffers(page))
 485                 return;
 486
 487         bh = head = page_buffers(page);
 488         do {
 489                 unsigned int next_off = curr_off + bh->b_size;
 490                 next = bh->b_this_page;
 491
 492                 if (offset <= curr_off)
 493                         discard_buffer(sdp, bh);
 494
 495                 curr_off = next_off;
 496                 bh = next;
 497         } while (bh != head);
 498
 499         if (!offset)
 500                 try_to_release_page(page, 0);
 501
 502         return;
 503 }
 504
 505 static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov,
 506                                     loff_t offset, unsigned long nr_segs)
 507 {
 508         struct file *file = iocb->ki_filp;
 509         struct inode *inode = file->f_mapping->host;
 510         struct gfs2_inode *ip = inode->u.generic_ip;
 511         struct gfs2_holder gh;
 512         int rv;
 513
 514         /*
 515          * Shared lock, even though its write, since we do no allocation
 516          * on this path. All we need change is atime.
 517          */
 518         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
 519         rv = gfs2_glock_nq_m_atime(1, &gh);
 520         if (rv)
 521                 goto out;
 522
 523         /*
 524          * Should we return an error here? I can't see that O_DIRECT for
 525          * a journaled file makes any sense. For now we'll silently fall
 526          * back to buffered I/O, likewise we do the same for stuffed
 527          * files since they are (a) small and (b) unaligned.
 528          */
 529         if (gfs2_is_jdata(ip))
 530                 goto out;
 531
 532         if (gfs2_is_stuffed(ip))
 533                 goto out;
 534
 535         rv = __blockdev_direct_IO(WRITE, iocb, inode, inode->i_sb->s_bdev,
 536                                   iov, offset, nr_segs, gfs2_get_block,
 537                                   NULL, DIO_OWN_LOCKING);
 538 out:
 539         gfs2_glock_dq_m(1, &gh);
 540         gfs2_holder_uninit(&gh);
 541
 542         return rv;
 543 }
 544
 545 /**
 546  * gfs2_direct_IO
 547  *
 548  * This is called with a shared lock already held for the read path.
 549  * Currently, no locks are held when the write path is called.
 550  */
 551 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 552                               const struct iovec *iov, loff_t offset,
 553                               unsigned long nr_segs)
 554 {
 555         struct file *file = iocb->ki_filp;
 556         struct inode *inode = file->f_mapping->host;
 557         struct gfs2_inode *ip = inode->u.generic_ip;
 558         struct gfs2_sbd *sdp = ip->i_sbd;
 559
 560         if (rw == WRITE)
 561                 return gfs2_direct_IO_write(iocb, iov, offset, nr_segs);
 562
 563         if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)) ||
 564             gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip)))
 565                 return -EINVAL;
 566
 567         return __blockdev_direct_IO(READ, iocb, inode, inode->i_sb->s_bdev, iov,
 568                                     offset, nr_segs, gfs2_get_block, NULL,
 569                                     DIO_OWN_LOCKING);
 570 }
 571
 572 struct address_space_operations gfs2_file_aops = {
 573         .writepage = gfs2_writepage,
 574         .readpage = gfs2_readpage,
 575         .sync_page = block_sync_page,
 576         .prepare_write = gfs2_prepare_write,
 577         .commit_write = gfs2_commit_write,
 578         .bmap = gfs2_bmap,
 579         .invalidatepage = gfs2_invalidatepage,
 580         .direct_IO = gfs2_direct_IO,
 581 };
 582