fs/f2fs/data.c

   1 /*
   2  * fs/f2fs/data.c
   3  *
   4  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   5  *             http://www.samsung.com/
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/fs.h>
  12 #include <linux/f2fs_fs.h>
  13 #include <linux/buffer_head.h>
  14 #include <linux/mpage.h>
  15 #include <linux/aio.h>
  16 #include <linux/writeback.h>
  17 #include <linux/backing-dev.h>
  18 #include <linux/blkdev.h>
  19 #include <linux/bio.h>
  20 #include <linux/prefetch.h>
  21
  22 #include "f2fs.h"
  23 #include "node.h"
  24 #include "segment.h"
  25 #include <trace/events/f2fs.h>
  26
  27 /*
  28  * Lock ordering for the change of data block address:
  29  * ->data_page
  30  *  ->node_page
  31  *    update block addresses in the node page
  32  */
  33 static void __set_data_blkaddr(struct dnode_of_data *dn, block_t new_addr)
  34 {
  35         struct f2fs_node *rn;
  36         __le32 *addr_array;
  37         struct page *node_page = dn->node_page;
  38         unsigned int ofs_in_node = dn->ofs_in_node;
  39
  40         f2fs_wait_on_page_writeback(node_page, NODE, false);
  41
  42         rn = F2FS_NODE(node_page);
  43
  44         /* Get physical address of data block */
  45         addr_array = blkaddr_in_node(rn);
  46         addr_array[ofs_in_node] = cpu_to_le32(new_addr);
  47         set_page_dirty(node_page);
  48 }
  49
  50 int reserve_new_block(struct dnode_of_data *dn)
  51 {
  52         struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
  53
  54         if (is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC))
  55                 return -EPERM;
  56         if (!inc_valid_block_count(sbi, dn->inode, 1))
  57                 return -ENOSPC;
  58
  59         trace_f2fs_reserve_new_block(dn->inode, dn->nid, dn->ofs_in_node);
  60
  61         __set_data_blkaddr(dn, NEW_ADDR);
  62         dn->data_blkaddr = NEW_ADDR;
  63         sync_inode_page(dn);
  64         return 0;
  65 }
  66
  67 static int check_extent_cache(struct inode *inode, pgoff_t pgofs,
  68                                         struct buffer_head *bh_result)
  69 {
  70         struct f2fs_inode_info *fi = F2FS_I(inode);
  71         pgoff_t start_fofs, end_fofs;
  72         block_t start_blkaddr;
  73
  74         read_lock(&fi->ext.ext_lock);
  75         if (fi->ext.len == 0) {
  76                 read_unlock(&fi->ext.ext_lock);
  77                 return 0;
  78         }
  79
  80         stat_inc_total_hit(inode->i_sb);
  81
  82         start_fofs = fi->ext.fofs;
  83         end_fofs = fi->ext.fofs + fi->ext.len - 1;
  84         start_blkaddr = fi->ext.blk_addr;
  85
  86         if (pgofs >= start_fofs && pgofs <= end_fofs) {
  87                 unsigned int blkbits = inode->i_sb->s_blocksize_bits;
  88                 size_t count;
  89
  90                 clear_buffer_new(bh_result);
  91                 map_bh(bh_result, inode->i_sb,
  92                                 start_blkaddr + pgofs - start_fofs);
  93                 count = end_fofs - pgofs + 1;
  94                 if (count < (UINT_MAX >> blkbits))
  95                         bh_result->b_size = (count << blkbits);
  96                 else
  97                         bh_result->b_size = UINT_MAX;
  98
  99                 stat_inc_read_hit(inode->i_sb);
 100                 read_unlock(&fi->ext.ext_lock);
 101                 return 1;
 102         }
 103         read_unlock(&fi->ext.ext_lock);
 104         return 0;
 105 }
 106
 107 void update_extent_cache(block_t blk_addr, struct dnode_of_data *dn)
 108 {
 109         struct f2fs_inode_info *fi = F2FS_I(dn->inode);
 110         pgoff_t fofs, start_fofs, end_fofs;
 111         block_t start_blkaddr, end_blkaddr;
 112
 113         f2fs_bug_on(blk_addr == NEW_ADDR);
 114         fofs = start_bidx_of_node(ofs_of_node(dn->node_page), fi) +
 115                                                         dn->ofs_in_node;
 116
 117         /* Update the page address in the parent node */
 118         __set_data_blkaddr(dn, blk_addr);
 119
 120         write_lock(&fi->ext.ext_lock);
 121
 122         start_fofs = fi->ext.fofs;
 123         end_fofs = fi->ext.fofs + fi->ext.len - 1;
 124         start_blkaddr = fi->ext.blk_addr;
 125         end_blkaddr = fi->ext.blk_addr + fi->ext.len - 1;
 126
 127         /* Drop and initialize the matched extent */
 128         if (fi->ext.len == 1 && fofs == start_fofs)
 129                 fi->ext.len = 0;
 130
 131         /* Initial extent */
 132         if (fi->ext.len == 0) {
 133                 if (blk_addr != NULL_ADDR) {
 134                         fi->ext.fofs = fofs;
 135                         fi->ext.blk_addr = blk_addr;
 136                         fi->ext.len = 1;
 137                 }
 138                 goto end_update;
 139         }
 140
 141         /* Front merge */
 142         if (fofs == start_fofs - 1 && blk_addr == start_blkaddr - 1) {
 143                 fi->ext.fofs--;
 144                 fi->ext.blk_addr--;
 145                 fi->ext.len++;
 146                 goto end_update;
 147         }
 148
 149         /* Back merge */
 150         if (fofs == end_fofs + 1 && blk_addr == end_blkaddr + 1) {
 151                 fi->ext.len++;
 152                 goto end_update;
 153         }
 154
 155         /* Split the existing extent */
 156         if (fi->ext.len > 1 &&
 157                 fofs >= start_fofs && fofs <= end_fofs) {
 158                 if ((end_fofs - fofs) < (fi->ext.len >> 1)) {
 159                         fi->ext.len = fofs - start_fofs;
 160                 } else {
 161                         fi->ext.fofs = fofs + 1;
 162                         fi->ext.blk_addr = start_blkaddr +
 163                                         fofs - start_fofs + 1;
 164                         fi->ext.len -= fofs - start_fofs + 1;
 165                 }
 166                 goto end_update;
 167         }
 168         write_unlock(&fi->ext.ext_lock);
 169         return;
 170
 171 end_update:
 172         write_unlock(&fi->ext.ext_lock);
 173         sync_inode_page(dn);
 174 }
 175
 176 struct page *find_data_page(struct inode *inode, pgoff_t index, bool sync)
 177 {
 178         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 179         struct address_space *mapping = inode->i_mapping;
 180         struct dnode_of_data dn;
 181         struct page *page;
 182         int err;
 183
 184         page = find_get_page(mapping, index);
 185         if (page && PageUptodate(page))
 186                 return page;
 187         f2fs_put_page(page, 0);
 188
 189         set_new_dnode(&dn, inode, NULL, NULL, 0);
 190         err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
 191         if (err)
 192                 return ERR_PTR(err);
 193         f2fs_put_dnode(&dn);
 194
 195         if (dn.data_blkaddr == NULL_ADDR)
 196                 return ERR_PTR(-ENOENT);
 197
 198         /* By fallocate(), there is no cached page, but with NEW_ADDR */
 199         if (dn.data_blkaddr == NEW_ADDR)
 200                 return ERR_PTR(-EINVAL);
 201
 202         page = grab_cache_page_write_begin(mapping, index, AOP_FLAG_NOFS);
 203         if (!page)
 204                 return ERR_PTR(-ENOMEM);
 205
 206         if (PageUptodate(page)) {
 207                 unlock_page(page);
 208                 return page;
 209         }
 210
 211         err = f2fs_readpage(sbi, page, dn.data_blkaddr,
 212                                         sync ? READ_SYNC : READA);
 213         if (sync) {
 214                 wait_on_page_locked(page);
 215                 if (!PageUptodate(page)) {
 216                         f2fs_put_page(page, 0);
 217                         return ERR_PTR(-EIO);
 218                 }
 219         }
 220         return page;
 221 }
 222
 223 /*
 224  * If it tries to access a hole, return an error.
 225  * Because, the callers, functions in dir.c and GC, should be able to know
 226  * whether this page exists or not.
 227  */
 228 struct page *get_lock_data_page(struct inode *inode, pgoff_t index)
 229 {
 230         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 231         struct address_space *mapping = inode->i_mapping;
 232         struct dnode_of_data dn;
 233         struct page *page;
 234         int err;
 235
 236 repeat:
 237         page = grab_cache_page_write_begin(mapping, index, AOP_FLAG_NOFS);
 238         if (!page)
 239                 return ERR_PTR(-ENOMEM);
 240
 241         set_new_dnode(&dn, inode, NULL, NULL, 0);
 242         err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
 243         if (err) {
 244                 f2fs_put_page(page, 1);
 245                 return ERR_PTR(err);
 246         }
 247         f2fs_put_dnode(&dn);
 248
 249         if (dn.data_blkaddr == NULL_ADDR) {
 250                 f2fs_put_page(page, 1);
 251                 return ERR_PTR(-ENOENT);
 252         }
 253
 254         if (PageUptodate(page))
 255                 return page;
 256
 257         /*
 258          * A new dentry page is allocated but not able to be written, since its
 259          * new inode page couldn't be allocated due to -ENOSPC.
 260          * In such the case, its blkaddr can be remained as NEW_ADDR.
 261          * see, f2fs_add_link -> get_new_data_page -> init_inode_metadata.
 262          */
 263         if (dn.data_blkaddr == NEW_ADDR) {
 264                 zero_user_segment(page, 0, PAGE_CACHE_SIZE);
 265                 SetPageUptodate(page);
 266                 return page;
 267         }
 268
 269         err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
 270         if (err)
 271                 return ERR_PTR(err);
 272
 273         lock_page(page);
 274         if (!PageUptodate(page)) {
 275                 f2fs_put_page(page, 1);
 276                 return ERR_PTR(-EIO);
 277         }
 278         if (page->mapping != mapping) {
 279                 f2fs_put_page(page, 1);
 280                 goto repeat;
 281         }
 282         return page;
 283 }
 284
 285 /*
 286  * Caller ensures that this data page is never allocated.
 287  * A new zero-filled data page is allocated in the page cache.
 288  *
 289  * Also, caller should grab and release a mutex by calling mutex_lock_op() and
 290  * mutex_unlock_op().
 291  * Note that, npage is set only by make_empty_dir.
 292  */
 293 struct page *get_new_data_page(struct inode *inode,
 294                 struct page *npage, pgoff_t index, bool new_i_size)
 295 {
 296         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 297         struct address_space *mapping = inode->i_mapping;
 298         struct page *page;
 299         struct dnode_of_data dn;
 300         int err;
 301
 302         set_new_dnode(&dn, inode, npage, npage, 0);
 303         err = get_dnode_of_data(&dn, index, ALLOC_NODE);
 304         if (err)
 305                 return ERR_PTR(err);
 306
 307         if (dn.data_blkaddr == NULL_ADDR) {
 308                 if (reserve_new_block(&dn)) {
 309                         if (!npage)
 310                                 f2fs_put_dnode(&dn);
 311                         return ERR_PTR(-ENOSPC);
 312                 }
 313         }
 314         if (!npage)
 315                 f2fs_put_dnode(&dn);
 316 repeat:
 317         page = grab_cache_page(mapping, index);
 318         if (!page)
 319                 return ERR_PTR(-ENOMEM);
 320
 321         if (PageUptodate(page))
 322                 return page;
 323
 324         if (dn.data_blkaddr == NEW_ADDR) {
 325                 zero_user_segment(page, 0, PAGE_CACHE_SIZE);
 326                 SetPageUptodate(page);
 327         } else {
 328                 err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
 329                 if (err)
 330                         return ERR_PTR(err);
 331                 lock_page(page);
 332                 if (!PageUptodate(page)) {
 333                         f2fs_put_page(page, 1);
 334                         return ERR_PTR(-EIO);
 335                 }
 336                 if (page->mapping != mapping) {
 337                         f2fs_put_page(page, 1);
 338                         goto repeat;
 339                 }
 340         }
 341
 342         if (new_i_size &&
 343                 i_size_read(inode) < ((index + 1) << PAGE_CACHE_SHIFT)) {
 344                 i_size_write(inode, ((index + 1) << PAGE_CACHE_SHIFT));
 345                 /* Only the directory inode sets new_i_size */
 346                 set_inode_flag(F2FS_I(inode), FI_UPDATE_DIR);
 347                 mark_inode_dirty_sync(inode);
 348         }
 349         return page;
 350 }
 351
 352 static void read_end_io(struct bio *bio, int err)
 353 {
 354         const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 355         struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
 356
 357         do {
 358                 struct page *page = bvec->bv_page;
 359
 360                 if (--bvec >= bio->bi_io_vec)
 361                         prefetchw(&bvec->bv_page->flags);
 362
 363                 if (uptodate) {
 364                         SetPageUptodate(page);
 365                 } else {
 366                         ClearPageUptodate(page);
 367                         SetPageError(page);
 368                 }
 369                 unlock_page(page);
 370         } while (bvec >= bio->bi_io_vec);
 371         bio_put(bio);
 372 }
 373
 374 /*
 375  * Fill the locked page with data located in the block address.
 376  * Return unlocked page.
 377  */
 378 int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
 379                                         block_t blk_addr, int type)
 380 {
 381         struct block_device *bdev = sbi->sb->s_bdev;
 382         struct bio *bio;
 383
 384         trace_f2fs_readpage(page, blk_addr, type);
 385
 386         down_read(&sbi->bio_sem);
 387
 388         /* Allocate a new bio */
 389         bio = f2fs_bio_alloc(bdev, 1);
 390
 391         /* Initialize the bio */
 392         bio->bi_sector = SECTOR_FROM_BLOCK(sbi, blk_addr);
 393         bio->bi_end_io = read_end_io;
 394
 395         if (bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < PAGE_CACHE_SIZE) {
 396                 bio_put(bio);
 397                 up_read(&sbi->bio_sem);
 398                 f2fs_put_page(page, 1);
 399                 return -EFAULT;
 400         }
 401
 402         submit_bio(type, bio);
 403         up_read(&sbi->bio_sem);
 404         return 0;
 405 }
 406
 407 /*
 408  * This function should be used by the data read flow only where it
 409  * does not check the "create" flag that indicates block allocation.
 410  * The reason for this special functionality is to exploit VFS readahead
 411  * mechanism.
 412  */
 413 static int get_data_block_ro(struct inode *inode, sector_t iblock,
 414                         struct buffer_head *bh_result, int create)
 415 {
 416         unsigned int blkbits = inode->i_sb->s_blocksize_bits;
 417         unsigned maxblocks = bh_result->b_size >> blkbits;
 418         struct dnode_of_data dn;
 419         pgoff_t pgofs;
 420         int err;
 421
 422         /* Get the page offset from the block offset(iblock) */
 423         pgofs = (pgoff_t)(iblock >> (PAGE_CACHE_SHIFT - blkbits));
 424
 425         if (check_extent_cache(inode, pgofs, bh_result)) {
 426                 trace_f2fs_get_data_block(inode, iblock, bh_result, 0);
 427                 return 0;
 428         }
 429
 430         /* When reading holes, we need its node page */
 431         set_new_dnode(&dn, inode, NULL, NULL, 0);
 432         err = get_dnode_of_data(&dn, pgofs, LOOKUP_NODE_RA);
 433         if (err) {
 434                 trace_f2fs_get_data_block(inode, iblock, bh_result, err);
 435                 return (err == -ENOENT) ? 0 : err;
 436         }
 437
 438         /* It does not support data allocation */
 439         f2fs_bug_on(create);
 440
 441         if (dn.data_blkaddr != NEW_ADDR && dn.data_blkaddr != NULL_ADDR) {
 442                 int i;
 443                 unsigned int end_offset;
 444
 445                 end_offset = IS_INODE(dn.node_page) ?
 446                                 ADDRS_PER_INODE(F2FS_I(inode)) :
 447                                 ADDRS_PER_BLOCK;
 448
 449                 clear_buffer_new(bh_result);
 450
 451                 /* Give more consecutive addresses for the read ahead */
 452                 for (i = 0; i < end_offset - dn.ofs_in_node; i++)
 453                         if (((datablock_addr(dn.node_page,
 454                                                         dn.ofs_in_node + i))
 455                                 != (dn.data_blkaddr + i)) || maxblocks == i)
 456                                 break;
 457                 map_bh(bh_result, inode->i_sb, dn.data_blkaddr);
 458                 bh_result->b_size = (i << blkbits);
 459         }
 460         f2fs_put_dnode(&dn);
 461         trace_f2fs_get_data_block(inode, iblock, bh_result, 0);
 462         return 0;
 463 }
 464
 465 static int f2fs_read_data_page(struct file *file, struct page *page)
 466 {
 467         return mpage_readpage(page, get_data_block_ro);
 468 }
 469
 470 static int f2fs_read_data_pages(struct file *file,
 471                         struct address_space *mapping,
 472                         struct list_head *pages, unsigned nr_pages)
 473 {
 474         return mpage_readpages(mapping, pages, nr_pages, get_data_block_ro);
 475 }
 476
 477 int do_write_data_page(struct page *page)
 478 {
 479         struct inode *inode = page->mapping->host;
 480         block_t old_blk_addr, new_blk_addr;
 481         struct dnode_of_data dn;
 482         int err = 0;
 483
 484         set_new_dnode(&dn, inode, NULL, NULL, 0);
 485         err = get_dnode_of_data(&dn, page->index, LOOKUP_NODE);
 486         if (err)
 487                 return err;
 488
 489         old_blk_addr = dn.data_blkaddr;
 490
 491         /* This page is already truncated */
 492         if (old_blk_addr == NULL_ADDR)
 493                 goto out_writepage;
 494
 495         set_page_writeback(page);
 496
 497         /*
 498          * If current allocation needs SSR,
 499          * it had better in-place writes for updated data.
 500          */
 501         if (unlikely(old_blk_addr != NEW_ADDR &&
 502                         !is_cold_data(page) &&
 503                         need_inplace_update(inode))) {
 504                 rewrite_data_page(F2FS_SB(inode->i_sb), page,
 505                                                 old_blk_addr);
 506         } else {
 507                 write_data_page(inode, page, &dn,
 508                                 old_blk_addr, &new_blk_addr);
 509                 update_extent_cache(new_blk_addr, &dn);
 510         }
 511 out_writepage:
 512         f2fs_put_dnode(&dn);
 513         return err;
 514 }
 515
 516 static int f2fs_write_data_page(struct page *page,
 517                                         struct writeback_control *wbc)
 518 {
 519         struct inode *inode = page->mapping->host;
 520         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 521         loff_t i_size = i_size_read(inode);
 522         const pgoff_t end_index = ((unsigned long long) i_size)
 523                                                         >> PAGE_CACHE_SHIFT;
 524         unsigned offset;
 525         bool need_balance_fs = false;
 526         int err = 0;
 527
 528         if (page->index < end_index)
 529                 goto write;
 530
 531         /*
 532          * If the offset is out-of-range of file size,
 533          * this page does not have to be written to disk.
 534          */
 535         offset = i_size & (PAGE_CACHE_SIZE - 1);
 536         if ((page->index >= end_index + 1) || !offset) {
 537                 if (S_ISDIR(inode->i_mode)) {
 538                         dec_page_count(sbi, F2FS_DIRTY_DENTS);
 539                         inode_dec_dirty_dents(inode);
 540                 }
 541                 goto out;
 542         }
 543
 544         zero_user_segment(page, offset, PAGE_CACHE_SIZE);
 545 write:
 546         if (sbi->por_doing) {
 547                 err = AOP_WRITEPAGE_ACTIVATE;
 548                 goto redirty_out;
 549         }
 550
 551         /* Dentry blocks are controlled by checkpoint */
 552         if (S_ISDIR(inode->i_mode)) {
 553                 dec_page_count(sbi, F2FS_DIRTY_DENTS);
 554                 inode_dec_dirty_dents(inode);
 555                 err = do_write_data_page(page);
 556         } else {
 557                 f2fs_lock_op(sbi);
 558                 err = do_write_data_page(page);
 559                 f2fs_unlock_op(sbi);
 560                 need_balance_fs = true;
 561         }
 562         if (err == -ENOENT)
 563                 goto out;
 564         else if (err)
 565                 goto redirty_out;
 566
 567         if (wbc->for_reclaim)
 568                 f2fs_submit_bio(sbi, DATA, true);
 569
 570         clear_cold_data(page);
 571 out:
 572         unlock_page(page);
 573         if (need_balance_fs)
 574                 f2fs_balance_fs(sbi);
 575         return 0;
 576
 577 redirty_out:
 578         wbc->pages_skipped++;
 579         set_page_dirty(page);
 580         return err;
 581 }
 582
 583 #define MAX_DESIRED_PAGES_WP    4096
 584
 585 static int __f2fs_writepage(struct page *page, struct writeback_control *wbc,
 586                         void *data)
 587 {
 588         struct address_space *mapping = data;
 589         int ret = mapping->a_ops->writepage(page, wbc);
 590         mapping_set_error(mapping, ret);
 591         return ret;
 592 }
 593
 594 static int f2fs_write_data_pages(struct address_space *mapping,
 595                             struct writeback_control *wbc)
 596 {
 597         struct inode *inode = mapping->host;
 598         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 599         bool locked = false;
 600         int ret;
 601         long excess_nrtw = 0, desired_nrtw;
 602
 603         /* deal with chardevs and other special file */
 604         if (!mapping->a_ops->writepage)
 605                 return 0;
 606
 607         if (wbc->nr_to_write < MAX_DESIRED_PAGES_WP) {
 608                 desired_nrtw = MAX_DESIRED_PAGES_WP;
 609                 excess_nrtw = desired_nrtw - wbc->nr_to_write;
 610                 wbc->nr_to_write = desired_nrtw;
 611         }
 612
 613         if (!S_ISDIR(inode->i_mode)) {
 614                 mutex_lock(&sbi->writepages);
 615                 locked = true;
 616         }
 617         ret = write_cache_pages(mapping, wbc, __f2fs_writepage, mapping);
 618         if (locked)
 619                 mutex_unlock(&sbi->writepages);
 620         f2fs_submit_bio(sbi, DATA, (wbc->sync_mode == WB_SYNC_ALL));
 621
 622         remove_dirty_dir_inode(inode);
 623
 624         wbc->nr_to_write -= excess_nrtw;
 625         return ret;
 626 }
 627
 628 static int f2fs_write_begin(struct file *file, struct address_space *mapping,
 629                 loff_t pos, unsigned len, unsigned flags,
 630                 struct page **pagep, void **fsdata)
 631 {
 632         struct inode *inode = mapping->host;
 633         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 634         struct page *page;
 635         pgoff_t index = ((unsigned long long) pos) >> PAGE_CACHE_SHIFT;
 636         struct dnode_of_data dn;
 637         int err = 0;
 638
 639         f2fs_balance_fs(sbi);
 640 repeat:
 641         page = grab_cache_page_write_begin(mapping, index, flags);
 642         if (!page)
 643                 return -ENOMEM;
 644         *pagep = page;
 645
 646         f2fs_lock_op(sbi);
 647
 648         set_new_dnode(&dn, inode, NULL, NULL, 0);
 649         err = get_dnode_of_data(&dn, index, ALLOC_NODE);
 650         if (err)
 651                 goto err;
 652
 653         if (dn.data_blkaddr == NULL_ADDR)
 654                 err = reserve_new_block(&dn);
 655
 656         f2fs_put_dnode(&dn);
 657         if (err)
 658                 goto err;
 659
 660         f2fs_unlock_op(sbi);
 661
 662         if ((len == PAGE_CACHE_SIZE) || PageUptodate(page))
 663                 return 0;
 664
 665         if ((pos & PAGE_CACHE_MASK) >= i_size_read(inode)) {
 666                 unsigned start = pos & (PAGE_CACHE_SIZE - 1);
 667                 unsigned end = start + len;
 668
 669                 /* Reading beyond i_size is simple: memset to zero */
 670                 zero_user_segments(page, 0, start, end, PAGE_CACHE_SIZE);
 671                 goto out;
 672         }
 673
 674         if (dn.data_blkaddr == NEW_ADDR) {
 675                 zero_user_segment(page, 0, PAGE_CACHE_SIZE);
 676         } else {
 677                 err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
 678                 if (err)
 679                         return err;
 680                 lock_page(page);
 681                 if (!PageUptodate(page)) {
 682                         f2fs_put_page(page, 1);
 683                         return -EIO;
 684                 }
 685                 if (page->mapping != mapping) {
 686                         f2fs_put_page(page, 1);
 687                         goto repeat;
 688                 }
 689         }
 690 out:
 691         SetPageUptodate(page);
 692         clear_cold_data(page);
 693         return 0;
 694
 695 err:
 696         f2fs_unlock_op(sbi);
 697         f2fs_put_page(page, 1);
 698         return err;
 699 }
 700
 701 static int f2fs_write_end(struct file *file,
 702                         struct address_space *mapping,
 703                         loff_t pos, unsigned len, unsigned copied,
 704                         struct page *page, void *fsdata)
 705 {
 706         struct inode *inode = page->mapping->host;
 707
 708         SetPageUptodate(page);
 709         set_page_dirty(page);
 710
 711         if (pos + copied > i_size_read(inode)) {
 712                 i_size_write(inode, pos + copied);
 713                 mark_inode_dirty(inode);
 714                 update_inode_page(inode);
 715         }
 716
 717         unlock_page(page);
 718         page_cache_release(page);
 719         return copied;
 720 }
 721
 722 static ssize_t f2fs_direct_IO(int rw, struct kiocb *iocb,
 723                 const struct iovec *iov, loff_t offset, unsigned long nr_segs)
 724 {
 725         struct file *file = iocb->ki_filp;
 726         struct inode *inode = file->f_mapping->host;
 727
 728         if (rw == WRITE)
 729                 return 0;
 730
 731         /* Needs synchronization with the cleaner */
 732         return blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
 733                                                   get_data_block_ro);
 734 }
 735
 736 static void f2fs_invalidate_data_page(struct page *page, unsigned int offset,
 737                                       unsigned int length)
 738 {
 739         struct inode *inode = page->mapping->host;
 740         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 741         if (S_ISDIR(inode->i_mode) && PageDirty(page)) {
 742                 dec_page_count(sbi, F2FS_DIRTY_DENTS);
 743                 inode_dec_dirty_dents(inode);
 744         }
 745         ClearPagePrivate(page);
 746 }
 747
 748 static int f2fs_release_data_page(struct page *page, gfp_t wait)
 749 {
 750         ClearPagePrivate(page);
 751         return 1;
 752 }
 753
 754 static int f2fs_set_data_page_dirty(struct page *page)
 755 {
 756         struct address_space *mapping = page->mapping;
 757         struct inode *inode = mapping->host;
 758
 759         trace_f2fs_set_page_dirty(page, DATA);
 760
 761         SetPageUptodate(page);
 762         if (!PageDirty(page)) {
 763                 __set_page_dirty_nobuffers(page);
 764                 set_dirty_dir_page(inode, page);
 765                 return 1;
 766         }
 767         return 0;
 768 }
 769
 770 static sector_t f2fs_bmap(struct address_space *mapping, sector_t block)
 771 {
 772         return generic_block_bmap(mapping, block, get_data_block_ro);
 773 }
 774
 775 const struct address_space_operations f2fs_dblock_aops = {
 776         .readpage       = f2fs_read_data_page,
 777         .readpages      = f2fs_read_data_pages,
 778         .writepage      = f2fs_write_data_page,
 779         .writepages     = f2fs_write_data_pages,
 780         .write_begin    = f2fs_write_begin,
 781         .write_end      = f2fs_write_end,
 782         .set_page_dirty = f2fs_set_data_page_dirty,
 783         .invalidatepage = f2fs_invalidate_data_page,
 784         .releasepage    = f2fs_release_data_page,
 785         .direct_IO      = f2fs_direct_IO,
 786         .bmap           = f2fs_bmap,
 787 };