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         error = block_write_full_page(page, get_block_noalloc, wbc);
 193         if (done_trans)
 194                 gfs2_trans_end(sdp);
 195         gfs2_meta_cache_flush(ip);
 196         return error;
 197
 198 out_ignore:
 199         redirty_page_for_writepage(wbc, page);
 200         unlock_page(page);
 201         return 0;
 202 }
 203
 204 /**
 205  * stuffed_readpage - Fill in a Linux page with stuffed file data
 206  * @ip: the inode
 207  * @page: the page
 208  *
 209  * Returns: errno
 210  */
 211
 212 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
 213 {
 214         struct buffer_head *dibh;
 215         void *kaddr;
 216         int error;
 217
 218         error = gfs2_meta_inode_buffer(ip, &dibh);
 219         if (error)
 220                 return error;
 221
 222         kaddr = kmap_atomic(page, KM_USER0);
 223         memcpy((char *)kaddr,
 224                dibh->b_data + sizeof(struct gfs2_dinode),
 225                ip->i_di.di_size);
 226         memset((char *)kaddr + ip->i_di.di_size,
 227                0,
 228                PAGE_CACHE_SIZE - ip->i_di.di_size);
 229         kunmap_atomic(page, KM_USER0);
 230
 231         brelse(dibh);
 232
 233         SetPageUptodate(page);
 234
 235         return 0;
 236 }
 237
 238 static int zero_readpage(struct page *page)
 239 {
 240         void *kaddr;
 241
 242         kaddr = kmap_atomic(page, KM_USER0);
 243         memset(kaddr, 0, PAGE_CACHE_SIZE);
 244         kunmap_atomic(page, KM_USER0);
 245
 246         SetPageUptodate(page);
 247         unlock_page(page);
 248
 249         return 0;
 250 }
 251
 252 /**
 253  * gfs2_readpage - readpage with locking
 254  * @file: The file to read a page for. N.B. This may be NULL if we are
 255  * reading an internal file.
 256  * @page: The page to read
 257  *
 258  * Returns: errno
 259  */
 260
 261 static int gfs2_readpage(struct file *file, struct page *page)
 262 {
 263         struct gfs2_inode *ip = get_v2ip(page->mapping->host);
 264         struct gfs2_sbd *sdp = ip->i_sbd;
 265         struct gfs2_holder gh;
 266         int error;
 267
 268         atomic_inc(&sdp->sd_ops_address);
 269
 270         if (file != &gfs2_internal_file_sentinal) {
 271                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
 272                 error = gfs2_glock_nq_m_atime(1, &gh);
 273                 if (error)
 274                         goto out_unlock;
 275         }
 276
 277         if (gfs2_is_stuffed(ip)) {
 278                 if (!page->index) {
 279                         error = stuffed_readpage(ip, page);
 280                         unlock_page(page);
 281                 } else
 282                         error = zero_readpage(page);
 283         } else
 284                 error = mpage_readpage(page, gfs2_get_block);
 285
 286         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 287                 error = -EIO;
 288
 289         if (file != &gfs2_internal_file_sentinal) {
 290                 gfs2_glock_dq_m(1, &gh);
 291                 gfs2_holder_uninit(&gh);
 292         }
 293 out:
 294         return error;
 295 out_unlock:
 296         unlock_page(page);
 297         goto out;
 298 }
 299
 300 /**
 301  * gfs2_prepare_write - Prepare to write a page to a file
 302  * @file: The file to write to
 303  * @page: The page which is to be prepared for writing
 304  * @from: From (byte range within page)
 305  * @to: To (byte range within page)
 306  *
 307  * Returns: errno
 308  */
 309
 310 static int gfs2_prepare_write(struct file *file, struct page *page,
 311                               unsigned from, unsigned to)
 312 {
 313         struct gfs2_inode *ip = get_v2ip(page->mapping->host);
 314         struct gfs2_sbd *sdp = ip->i_sbd;
 315         unsigned int data_blocks, ind_blocks, rblocks;
 316         int alloc_required;
 317         int error = 0;
 318         loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + from;
 319         loff_t end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
 320         struct gfs2_alloc *al;
 321
 322         atomic_inc(&sdp->sd_ops_address);
 323
 324         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME, &ip->i_gh);
 325         error = gfs2_glock_nq_m_atime(1, &ip->i_gh);
 326         if (error)
 327                 goto out_uninit;
 328
 329         gfs2_write_calc_reserv(ip, to - from, &data_blocks, &ind_blocks);
 330
 331         error = gfs2_write_alloc_required(ip, pos, from - to, &alloc_required);
 332         if (error)
 333                 goto out_unlock;
 334
 335
 336         if (alloc_required) {
 337                 al = gfs2_alloc_get(ip);
 338
 339                 error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
 340                 if (error)
 341                         goto out_alloc_put;
 342
 343                 error = gfs2_quota_check(ip, ip->i_di.di_uid, ip->i_di.di_gid);
 344                 if (error)
 345                         goto out_qunlock;
 346
 347                 al->al_requested = data_blocks + ind_blocks;
 348                 error = gfs2_inplace_reserve(ip);
 349                 if (error)
 350                         goto out_qunlock;
 351         }
 352
 353         rblocks = RES_DINODE + ind_blocks;
 354         if (gfs2_is_jdata(ip))
 355                 rblocks += data_blocks ? data_blocks : 1;
 356         if (ind_blocks || data_blocks)
 357                 rblocks += RES_STATFS + RES_QUOTA;
 358
 359         error = gfs2_trans_begin(sdp, rblocks, 0);
 360         if (error)
 361                 goto out;
 362
 363         if (gfs2_is_stuffed(ip)) {
 364                 if (end > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
 365                         error = gfs2_unstuff_dinode(ip, gfs2_unstuffer_page, 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 = get_v2ip(inode);
 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         atomic_inc(&sdp->sd_ops_address);
 416
 417
 418         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)))
 419                 goto fail_nounlock;
 420
 421         error = gfs2_meta_inode_buffer(ip, &dibh);
 422         if (error)
 423                 goto fail_endtrans;
 424
 425         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 426
 427         if (gfs2_is_stuffed(ip)) {
 428                 uint64_t file_size;
 429                 void *kaddr;
 430
 431                 file_size = ((uint64_t)page->index << PAGE_CACHE_SHIFT) + to;
 432
 433                 kaddr = kmap_atomic(page, KM_USER0);
 434                 memcpy(dibh->b_data + sizeof(struct gfs2_dinode) + from,
 435                        (char *)kaddr + from, to - from);
 436                 kunmap_atomic(page, KM_USER0);
 437
 438                 SetPageUptodate(page);
 439
 440                 if (inode->i_size < file_size)
 441                         i_size_write(inode, file_size);
 442         } else {
 443                 if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip))
 444                         gfs2_page_add_databufs(ip, page, from, to);
 445                 error = generic_commit_write(file, page, from, to);
 446                 if (error)
 447                         goto fail;
 448         }
 449
 450         if (ip->i_di.di_size < inode->i_size)
 451                 ip->i_di.di_size = inode->i_size;
 452
 453         gfs2_dinode_out(&ip->i_di, dibh->b_data);
 454         brelse(dibh);
 455         gfs2_trans_end(sdp);
 456         if (al->al_requested) {
 457                 gfs2_inplace_release(ip);
 458                 gfs2_quota_unlock(ip);
 459                 gfs2_alloc_put(ip);
 460         }
 461         gfs2_glock_dq_m(1, &ip->i_gh);
 462         gfs2_holder_uninit(&ip->i_gh);
 463         return 0;
 464
 465 fail:
 466         brelse(dibh);
 467 fail_endtrans:
 468         gfs2_trans_end(sdp);
 469         if (al->al_requested) {
 470                 gfs2_inplace_release(ip);
 471                 gfs2_quota_unlock(ip);
 472                 gfs2_alloc_put(ip);
 473         }
 474         gfs2_glock_dq_m(1, &ip->i_gh);
 475         gfs2_holder_uninit(&ip->i_gh);
 476 fail_nounlock:
 477         ClearPageUptodate(page);
 478         return error;
 479 }
 480
 481 /**
 482  * gfs2_bmap - Block map function
 483  * @mapping: Address space info
 484  * @lblock: The block to map
 485  *
 486  * Returns: The disk address for the block or 0 on hole or error
 487  */
 488
 489 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
 490 {
 491         struct gfs2_inode *ip = get_v2ip(mapping->host);
 492         struct gfs2_holder i_gh;
 493         sector_t dblock = 0;
 494         int error;
 495
 496         atomic_inc(&ip->i_sbd->sd_ops_address);
 497
 498         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 499         if (error)
 500                 return 0;
 501
 502         if (!gfs2_is_stuffed(ip))
 503                 dblock = generic_block_bmap(mapping, lblock, gfs2_get_block);
 504
 505         gfs2_glock_dq_uninit(&i_gh);
 506
 507         return dblock;
 508 }
 509
 510 static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
 511 {
 512         struct gfs2_bufdata *bd;
 513
 514         gfs2_log_lock(sdp);
 515         bd = get_v2bd(bh);
 516         if (bd) {
 517                 bd->bd_bh = NULL;
 518                 set_v2bd(bh, NULL);
 519                 gfs2_log_unlock(sdp);
 520                 brelse(bh);
 521         } else
 522                 gfs2_log_unlock(sdp);
 523
 524         lock_buffer(bh);
 525         clear_buffer_dirty(bh);
 526         bh->b_bdev = NULL;
 527         clear_buffer_mapped(bh);
 528         clear_buffer_req(bh);
 529         clear_buffer_new(bh);
 530         clear_buffer_delay(bh);
 531         unlock_buffer(bh);
 532 }
 533
 534 static int gfs2_invalidatepage(struct page *page, unsigned long offset)
 535 {
 536         struct gfs2_sbd *sdp = get_v2sdp(page->mapping->host->i_sb);
 537         struct buffer_head *head, *bh, *next;
 538         unsigned int curr_off = 0;
 539         int ret = 1;
 540
 541         BUG_ON(!PageLocked(page));
 542         if (!page_has_buffers(page))
 543                 return 1;
 544
 545         bh = head = page_buffers(page);
 546         do {
 547                 unsigned int next_off = curr_off + bh->b_size;
 548                 next = bh->b_this_page;
 549
 550                 if (offset <= curr_off)
 551                         discard_buffer(sdp, bh);
 552
 553                 curr_off = next_off;
 554                 bh = next;
 555         } while (bh != head);
 556
 557         if (!offset)
 558                 ret = try_to_release_page(page, 0);
 559
 560         return ret;
 561 }
 562
 563 static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov,
 564                                     loff_t offset, unsigned long nr_segs)
 565 {
 566         struct file *file = iocb->ki_filp;
 567         struct inode *inode = file->f_mapping->host;
 568         struct gfs2_inode *ip = get_v2ip(inode);
 569         struct gfs2_holder gh;
 570         int rv;
 571
 572         /*
 573          * Shared lock, even though its write, since we do no allocation
 574          * on this path. All we need change is atime.
 575          */
 576         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
 577         rv = gfs2_glock_nq_m_atime(1, &gh);
 578         if (rv)
 579                 goto out;
 580
 581         /*
 582          * Should we return an error here? I can't see that O_DIRECT for
 583          * a journaled file makes any sense. For now we'll silently fall
 584          * back to buffered I/O, likewise we do the same for stuffed
 585          * files since they are (a) small and (b) unaligned.
 586          */
 587         if (gfs2_is_jdata(ip))
 588                 goto out;
 589
 590         if (gfs2_is_stuffed(ip))
 591                 goto out;
 592
 593         rv = __blockdev_direct_IO(WRITE, iocb, inode, inode->i_sb->s_bdev,
 594                                   iov, offset, nr_segs, get_blocks_noalloc,
 595                                   NULL, DIO_OWN_LOCKING);
 596 out:
 597         gfs2_glock_dq_m(1, &gh);
 598         gfs2_holder_uninit(&gh);
 599
 600         return rv;
 601 }
 602
 603 /**
 604  * gfs2_direct_IO
 605  *
 606  * This is called with a shared lock already held for the read path.
 607  * Currently, no locks are held when the write path is called.
 608  */
 609 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 610                               const struct iovec *iov, loff_t offset,
 611                               unsigned long nr_segs)
 612 {
 613         struct file *file = iocb->ki_filp;
 614         struct inode *inode = file->f_mapping->host;
 615         struct gfs2_inode *ip = get_v2ip(inode);
 616         struct gfs2_sbd *sdp = ip->i_sbd;
 617
 618         atomic_inc(&sdp->sd_ops_address);
 619
 620         if (rw == WRITE)
 621                 return gfs2_direct_IO_write(iocb, iov, offset, nr_segs);
 622
 623         if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)) ||
 624             gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip)))
 625                 return -EINVAL;
 626
 627         return __blockdev_direct_IO(READ, iocb, inode, inode->i_sb->s_bdev, iov,
 628                                     offset, nr_segs, get_blocks, NULL,
 629                                     DIO_OWN_LOCKING);
 630 }
 631
 632 struct address_space_operations gfs2_file_aops = {
 633         .writepage = gfs2_writepage,
 634         .readpage = gfs2_readpage,
 635         .sync_page = block_sync_page,
 636         .prepare_write = gfs2_prepare_write,
 637         .commit_write = gfs2_commit_write,
 638         .bmap = gfs2_bmap,
 639         .invalidatepage = gfs2_invalidatepage,
 640         .direct_IO = gfs2_direct_IO,
 641 };
 642