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 #ifdef CONFIG_F2FS_STAT_FS
  72         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
  73 #endif
  74         pgoff_t start_fofs, end_fofs;
  75         block_t start_blkaddr;
  76
  77         read_lock(&fi->ext.ext_lock);
  78         if (fi->ext.len == 0) {
  79                 read_unlock(&fi->ext.ext_lock);
  80                 return 0;
  81         }
  82
  83 #ifdef CONFIG_F2FS_STAT_FS
  84         sbi->total_hit_ext++;
  85 #endif
  86         start_fofs = fi->ext.fofs;
  87         end_fofs = fi->ext.fofs + fi->ext.len - 1;
  88         start_blkaddr = fi->ext.blk_addr;
  89
  90         if (pgofs >= start_fofs && pgofs <= end_fofs) {
  91                 unsigned int blkbits = inode->i_sb->s_blocksize_bits;
  92                 size_t count;
  93
  94                 clear_buffer_new(bh_result);
  95                 map_bh(bh_result, inode->i_sb,
  96                                 start_blkaddr + pgofs - start_fofs);
  97                 count = end_fofs - pgofs + 1;
  98                 if (count < (UINT_MAX >> blkbits))
  99                         bh_result->b_size = (count << blkbits);
 100                 else
 101                         bh_result->b_size = UINT_MAX;
 102
 103 #ifdef CONFIG_F2FS_STAT_FS
 104                 sbi->read_hit_ext++;
 105 #endif
 106                 read_unlock(&fi->ext.ext_lock);
 107                 return 1;
 108         }
 109         read_unlock(&fi->ext.ext_lock);
 110         return 0;
 111 }
 112
 113 void update_extent_cache(block_t blk_addr, struct dnode_of_data *dn)
 114 {
 115         struct f2fs_inode_info *fi = F2FS_I(dn->inode);
 116         pgoff_t fofs, start_fofs, end_fofs;
 117         block_t start_blkaddr, end_blkaddr;
 118
 119         BUG_ON(blk_addr == NEW_ADDR);
 120         fofs = start_bidx_of_node(ofs_of_node(dn->node_page), fi) +
 121                                                         dn->ofs_in_node;
 122
 123         /* Update the page address in the parent node */
 124         __set_data_blkaddr(dn, blk_addr);
 125
 126         write_lock(&fi->ext.ext_lock);
 127
 128         start_fofs = fi->ext.fofs;
 129         end_fofs = fi->ext.fofs + fi->ext.len - 1;
 130         start_blkaddr = fi->ext.blk_addr;
 131         end_blkaddr = fi->ext.blk_addr + fi->ext.len - 1;
 132
 133         /* Drop and initialize the matched extent */
 134         if (fi->ext.len == 1 && fofs == start_fofs)
 135                 fi->ext.len = 0;
 136
 137         /* Initial extent */
 138         if (fi->ext.len == 0) {
 139                 if (blk_addr != NULL_ADDR) {
 140                         fi->ext.fofs = fofs;
 141                         fi->ext.blk_addr = blk_addr;
 142                         fi->ext.len = 1;
 143                 }
 144                 goto end_update;
 145         }
 146
 147         /* Front merge */
 148         if (fofs == start_fofs - 1 && blk_addr == start_blkaddr - 1) {
 149                 fi->ext.fofs--;
 150                 fi->ext.blk_addr--;
 151                 fi->ext.len++;
 152                 goto end_update;
 153         }
 154
 155         /* Back merge */
 156         if (fofs == end_fofs + 1 && blk_addr == end_blkaddr + 1) {
 157                 fi->ext.len++;
 158                 goto end_update;
 159         }
 160
 161         /* Split the existing extent */
 162         if (fi->ext.len > 1 &&
 163                 fofs >= start_fofs && fofs <= end_fofs) {
 164                 if ((end_fofs - fofs) < (fi->ext.len >> 1)) {
 165                         fi->ext.len = fofs - start_fofs;
 166                 } else {
 167                         fi->ext.fofs = fofs + 1;
 168                         fi->ext.blk_addr = start_blkaddr +
 169                                         fofs - start_fofs + 1;
 170                         fi->ext.len -= fofs - start_fofs + 1;
 171                 }
 172                 goto end_update;
 173         }
 174         write_unlock(&fi->ext.ext_lock);
 175         return;
 176
 177 end_update:
 178         write_unlock(&fi->ext.ext_lock);
 179         sync_inode_page(dn);
 180 }
 181
 182 struct page *find_data_page(struct inode *inode, pgoff_t index, bool sync)
 183 {
 184         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 185         struct address_space *mapping = inode->i_mapping;
 186         struct dnode_of_data dn;
 187         struct page *page;
 188         int err;
 189
 190         page = find_get_page(mapping, index);
 191         if (page && PageUptodate(page))
 192                 return page;
 193         f2fs_put_page(page, 0);
 194
 195         set_new_dnode(&dn, inode, NULL, NULL, 0);
 196         err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
 197         if (err)
 198                 return ERR_PTR(err);
 199         f2fs_put_dnode(&dn);
 200
 201         if (dn.data_blkaddr == NULL_ADDR)
 202                 return ERR_PTR(-ENOENT);
 203
 204         /* By fallocate(), there is no cached page, but with NEW_ADDR */
 205         if (dn.data_blkaddr == NEW_ADDR)
 206                 return ERR_PTR(-EINVAL);
 207
 208         page = grab_cache_page_write_begin(mapping, index, AOP_FLAG_NOFS);
 209         if (!page)
 210                 return ERR_PTR(-ENOMEM);
 211
 212         if (PageUptodate(page)) {
 213                 unlock_page(page);
 214                 return page;
 215         }
 216
 217         err = f2fs_readpage(sbi, page, dn.data_blkaddr,
 218                                         sync ? READ_SYNC : READA);
 219         if (sync) {
 220                 wait_on_page_locked(page);
 221                 if (!PageUptodate(page)) {
 222                         f2fs_put_page(page, 0);
 223                         return ERR_PTR(-EIO);
 224                 }
 225         }
 226         return page;
 227 }
 228
 229 /*
 230  * If it tries to access a hole, return an error.
 231  * Because, the callers, functions in dir.c and GC, should be able to know
 232  * whether this page exists or not.
 233  */
 234 struct page *get_lock_data_page(struct inode *inode, pgoff_t index)
 235 {
 236         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 237         struct address_space *mapping = inode->i_mapping;
 238         struct dnode_of_data dn;
 239         struct page *page;
 240         int err;
 241
 242 repeat:
 243         page = grab_cache_page_write_begin(mapping, index, AOP_FLAG_NOFS);
 244         if (!page)
 245                 return ERR_PTR(-ENOMEM);
 246
 247         set_new_dnode(&dn, inode, NULL, NULL, 0);
 248         err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
 249         if (err) {
 250                 f2fs_put_page(page, 1);
 251                 return ERR_PTR(err);
 252         }
 253         f2fs_put_dnode(&dn);
 254
 255         if (dn.data_blkaddr == NULL_ADDR) {
 256                 f2fs_put_page(page, 1);
 257                 return ERR_PTR(-ENOENT);
 258         }
 259
 260         if (PageUptodate(page))
 261                 return page;
 262
 263         /*
 264          * A new dentry page is allocated but not able to be written, since its
 265          * new inode page couldn't be allocated due to -ENOSPC.
 266          * In such the case, its blkaddr can be remained as NEW_ADDR.
 267          * see, f2fs_add_link -> get_new_data_page -> init_inode_metadata.
 268          */
 269         if (dn.data_blkaddr == NEW_ADDR) {
 270                 zero_user_segment(page, 0, PAGE_CACHE_SIZE);
 271                 SetPageUptodate(page);
 272                 return page;
 273         }
 274
 275         err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
 276         if (err)
 277                 return ERR_PTR(err);
 278
 279         lock_page(page);
 280         if (!PageUptodate(page)) {
 281                 f2fs_put_page(page, 1);
 282                 return ERR_PTR(-EIO);
 283         }
 284         if (page->mapping != mapping) {
 285                 f2fs_put_page(page, 1);
 286                 goto repeat;
 287         }
 288         return page;
 289 }
 290
 291 /*
 292  * Caller ensures that this data page is never allocated.
 293  * A new zero-filled data page is allocated in the page cache.
 294  *
 295  * Also, caller should grab and release a mutex by calling mutex_lock_op() and
 296  * mutex_unlock_op().
 297  * Note that, npage is set only by make_empty_dir.
 298  */
 299 struct page *get_new_data_page(struct inode *inode,
 300                 struct page *npage, pgoff_t index, bool new_i_size)
 301 {
 302         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 303         struct address_space *mapping = inode->i_mapping;
 304         struct page *page;
 305         struct dnode_of_data dn;
 306         int err;
 307
 308         set_new_dnode(&dn, inode, npage, npage, 0);
 309         err = get_dnode_of_data(&dn, index, ALLOC_NODE);
 310         if (err)
 311                 return ERR_PTR(err);
 312
 313         if (dn.data_blkaddr == NULL_ADDR) {
 314                 if (reserve_new_block(&dn)) {
 315                         if (!npage)
 316                                 f2fs_put_dnode(&dn);
 317                         return ERR_PTR(-ENOSPC);
 318                 }
 319         }
 320         if (!npage)
 321                 f2fs_put_dnode(&dn);
 322 repeat:
 323         page = grab_cache_page(mapping, index);
 324         if (!page)
 325                 return ERR_PTR(-ENOMEM);
 326
 327         if (PageUptodate(page))
 328                 return page;
 329
 330         if (dn.data_blkaddr == NEW_ADDR) {
 331                 zero_user_segment(page, 0, PAGE_CACHE_SIZE);
 332                 SetPageUptodate(page);
 333         } else {
 334                 err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
 335                 if (err)
 336                         return ERR_PTR(err);
 337                 lock_page(page);
 338                 if (!PageUptodate(page)) {
 339                         f2fs_put_page(page, 1);
 340                         return ERR_PTR(-EIO);
 341                 }
 342                 if (page->mapping != mapping) {
 343                         f2fs_put_page(page, 1);
 344                         goto repeat;
 345                 }
 346         }
 347
 348         if (new_i_size &&
 349                 i_size_read(inode) < ((index + 1) << PAGE_CACHE_SHIFT)) {
 350                 i_size_write(inode, ((index + 1) << PAGE_CACHE_SHIFT));
 351                 /* Only the directory inode sets new_i_size */
 352                 set_inode_flag(F2FS_I(inode), FI_UPDATE_DIR);
 353                 mark_inode_dirty_sync(inode);
 354         }
 355         return page;
 356 }
 357
 358 static void read_end_io(struct bio *bio, int err)
 359 {
 360         const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 361         struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
 362
 363         do {
 364                 struct page *page = bvec->bv_page;
 365
 366                 if (--bvec >= bio->bi_io_vec)
 367                         prefetchw(&bvec->bv_page->flags);
 368
 369                 if (uptodate) {
 370                         SetPageUptodate(page);
 371                 } else {
 372                         ClearPageUptodate(page);
 373                         SetPageError(page);
 374                 }
 375                 unlock_page(page);
 376         } while (bvec >= bio->bi_io_vec);
 377         bio_put(bio);
 378 }
 379
 380 /*
 381  * Fill the locked page with data located in the block address.
 382  * Return unlocked page.
 383  */
 384 int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
 385                                         block_t blk_addr, int type)
 386 {
 387         struct block_device *bdev = sbi->sb->s_bdev;
 388         struct bio *bio;
 389
 390         trace_f2fs_readpage(page, blk_addr, type);
 391
 392         down_read(&sbi->bio_sem);
 393
 394         /* Allocate a new bio */
 395         bio = f2fs_bio_alloc(bdev, 1);
 396
 397         /* Initialize the bio */
 398         bio->bi_sector = SECTOR_FROM_BLOCK(sbi, blk_addr);
 399         bio->bi_end_io = read_end_io;
 400
 401         if (bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < PAGE_CACHE_SIZE) {
 402                 bio_put(bio);
 403                 up_read(&sbi->bio_sem);
 404                 f2fs_put_page(page, 1);
 405                 return -EFAULT;
 406         }
 407
 408         submit_bio(type, bio);
 409         up_read(&sbi->bio_sem);
 410         return 0;
 411 }
 412
 413 /*
 414  * This function should be used by the data read flow only where it
 415  * does not check the "create" flag that indicates block allocation.
 416  * The reason for this special functionality is to exploit VFS readahead
 417  * mechanism.
 418  */
 419 static int get_data_block_ro(struct inode *inode, sector_t iblock,
 420                         struct buffer_head *bh_result, int create)
 421 {
 422         unsigned int blkbits = inode->i_sb->s_blocksize_bits;
 423         unsigned maxblocks = bh_result->b_size >> blkbits;
 424         struct dnode_of_data dn;
 425         pgoff_t pgofs;
 426         int err;
 427
 428         /* Get the page offset from the block offset(iblock) */
 429         pgofs = (pgoff_t)(iblock >> (PAGE_CACHE_SHIFT - blkbits));
 430
 431         if (check_extent_cache(inode, pgofs, bh_result)) {
 432                 trace_f2fs_get_data_block(inode, iblock, bh_result, 0);
 433                 return 0;
 434         }
 435
 436         /* When reading holes, we need its node page */
 437         set_new_dnode(&dn, inode, NULL, NULL, 0);
 438         err = get_dnode_of_data(&dn, pgofs, LOOKUP_NODE_RA);
 439         if (err) {
 440                 trace_f2fs_get_data_block(inode, iblock, bh_result, err);
 441                 return (err == -ENOENT) ? 0 : err;
 442         }
 443
 444         /* It does not support data allocation */
 445         BUG_ON(create);
 446
 447         if (dn.data_blkaddr != NEW_ADDR && dn.data_blkaddr != NULL_ADDR) {
 448                 int i;
 449                 unsigned int end_offset;
 450
 451                 end_offset = IS_INODE(dn.node_page) ?
 452                                 ADDRS_PER_INODE(F2FS_I(inode)) :
 453                                 ADDRS_PER_BLOCK;
 454
 455                 clear_buffer_new(bh_result);
 456
 457                 /* Give more consecutive addresses for the read ahead */
 458                 for (i = 0; i < end_offset - dn.ofs_in_node; i++)
 459                         if (((datablock_addr(dn.node_page,
 460                                                         dn.ofs_in_node + i))
 461                                 != (dn.data_blkaddr + i)) || maxblocks == i)
 462                                 break;
 463                 map_bh(bh_result, inode->i_sb, dn.data_blkaddr);
 464                 bh_result->b_size = (i << blkbits);
 465         }
 466         f2fs_put_dnode(&dn);
 467         trace_f2fs_get_data_block(inode, iblock, bh_result, 0);
 468         return 0;
 469 }
 470
 471 static int f2fs_read_data_page(struct file *file, struct page *page)
 472 {
 473         return mpage_readpage(page, get_data_block_ro);
 474 }
 475
 476 static int f2fs_read_data_pages(struct file *file,
 477                         struct address_space *mapping,
 478                         struct list_head *pages, unsigned nr_pages)
 479 {
 480         return mpage_readpages(mapping, pages, nr_pages, get_data_block_ro);
 481 }
 482
 483 int do_write_data_page(struct page *page)
 484 {
 485         struct inode *inode = page->mapping->host;
 486         block_t old_blk_addr, new_blk_addr;
 487         struct dnode_of_data dn;
 488         int err = 0;
 489
 490         set_new_dnode(&dn, inode, NULL, NULL, 0);
 491         err = get_dnode_of_data(&dn, page->index, LOOKUP_NODE);
 492         if (err)
 493                 return err;
 494
 495         old_blk_addr = dn.data_blkaddr;
 496
 497         /* This page is already truncated */
 498         if (old_blk_addr == NULL_ADDR)
 499                 goto out_writepage;
 500
 501         set_page_writeback(page);
 502
 503         /*
 504          * If current allocation needs SSR,
 505          * it had better in-place writes for updated data.
 506          */
 507         if (unlikely(old_blk_addr != NEW_ADDR &&
 508                         !is_cold_data(page) &&
 509                         need_inplace_update(inode))) {
 510                 rewrite_data_page(F2FS_SB(inode->i_sb), page,
 511                                                 old_blk_addr);
 512         } else {
 513                 write_data_page(inode, page, &dn,
 514                                 old_blk_addr, &new_blk_addr);
 515                 update_extent_cache(new_blk_addr, &dn);
 516         }
 517 out_writepage:
 518         f2fs_put_dnode(&dn);
 519         return err;
 520 }
 521
 522 static int f2fs_write_data_page(struct page *page,
 523                                         struct writeback_control *wbc)
 524 {
 525         struct inode *inode = page->mapping->host;
 526         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 527         loff_t i_size = i_size_read(inode);
 528         const pgoff_t end_index = ((unsigned long long) i_size)
 529                                                         >> PAGE_CACHE_SHIFT;
 530         unsigned offset;
 531         bool need_balance_fs = false;
 532         int err = 0;
 533
 534         if (page->index < end_index)
 535                 goto write;
 536
 537         /*
 538          * If the offset is out-of-range of file size,
 539          * this page does not have to be written to disk.
 540          */
 541         offset = i_size & (PAGE_CACHE_SIZE - 1);
 542         if ((page->index >= end_index + 1) || !offset) {
 543                 if (S_ISDIR(inode->i_mode)) {
 544                         dec_page_count(sbi, F2FS_DIRTY_DENTS);
 545                         inode_dec_dirty_dents(inode);
 546                 }
 547                 goto out;
 548         }
 549
 550         zero_user_segment(page, offset, PAGE_CACHE_SIZE);
 551 write:
 552         if (sbi->por_doing) {
 553                 err = AOP_WRITEPAGE_ACTIVATE;
 554                 goto redirty_out;
 555         }
 556
 557         /* Dentry blocks are controlled by checkpoint */
 558         if (S_ISDIR(inode->i_mode)) {
 559                 dec_page_count(sbi, F2FS_DIRTY_DENTS);
 560                 inode_dec_dirty_dents(inode);
 561                 err = do_write_data_page(page);
 562         } else {
 563                 int ilock = mutex_lock_op(sbi);
 564                 err = do_write_data_page(page);
 565                 mutex_unlock_op(sbi, ilock);
 566                 need_balance_fs = true;
 567         }
 568         if (err == -ENOENT)
 569                 goto out;
 570         else if (err)
 571                 goto redirty_out;
 572
 573         if (wbc->for_reclaim)
 574                 f2fs_submit_bio(sbi, DATA, true);
 575
 576         clear_cold_data(page);
 577 out:
 578         unlock_page(page);
 579         if (need_balance_fs)
 580                 f2fs_balance_fs(sbi);
 581         return 0;
 582
 583 redirty_out:
 584         wbc->pages_skipped++;
 585         set_page_dirty(page);
 586         return err;
 587 }
 588
 589 #define MAX_DESIRED_PAGES_WP    4096
 590
 591 static int __f2fs_writepage(struct page *page, struct writeback_control *wbc,
 592                         void *data)
 593 {
 594         struct address_space *mapping = data;
 595         int ret = mapping->a_ops->writepage(page, wbc);
 596         mapping_set_error(mapping, ret);
 597         return ret;
 598 }
 599
 600 static int f2fs_write_data_pages(struct address_space *mapping,
 601                             struct writeback_control *wbc)
 602 {
 603         struct inode *inode = mapping->host;
 604         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 605         bool locked = false;
 606         int ret;
 607         long excess_nrtw = 0, desired_nrtw;
 608
 609         /* deal with chardevs and other special file */
 610         if (!mapping->a_ops->writepage)
 611                 return 0;
 612
 613         if (wbc->nr_to_write < MAX_DESIRED_PAGES_WP) {
 614                 desired_nrtw = MAX_DESIRED_PAGES_WP;
 615                 excess_nrtw = desired_nrtw - wbc->nr_to_write;
 616                 wbc->nr_to_write = desired_nrtw;
 617         }
 618
 619         if (!S_ISDIR(inode->i_mode)) {
 620                 mutex_lock(&sbi->writepages);
 621                 locked = true;
 622         }
 623         ret = write_cache_pages(mapping, wbc, __f2fs_writepage, mapping);
 624         if (locked)
 625                 mutex_unlock(&sbi->writepages);
 626         f2fs_submit_bio(sbi, DATA, (wbc->sync_mode == WB_SYNC_ALL));
 627
 628         remove_dirty_dir_inode(inode);
 629
 630         wbc->nr_to_write -= excess_nrtw;
 631         return ret;
 632 }
 633
 634 static int f2fs_write_begin(struct file *file, struct address_space *mapping,
 635                 loff_t pos, unsigned len, unsigned flags,
 636                 struct page **pagep, void **fsdata)
 637 {
 638         struct inode *inode = mapping->host;
 639         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 640         struct page *page;
 641         pgoff_t index = ((unsigned long long) pos) >> PAGE_CACHE_SHIFT;
 642         struct dnode_of_data dn;
 643         int err = 0;
 644         int ilock;
 645
 646         f2fs_balance_fs(sbi);
 647 repeat:
 648         page = grab_cache_page_write_begin(mapping, index, flags);
 649         if (!page)
 650                 return -ENOMEM;
 651         *pagep = page;
 652
 653         ilock = mutex_lock_op(sbi);
 654
 655         set_new_dnode(&dn, inode, NULL, NULL, 0);
 656         err = get_dnode_of_data(&dn, index, ALLOC_NODE);
 657         if (err)
 658                 goto err;
 659
 660         if (dn.data_blkaddr == NULL_ADDR)
 661                 err = reserve_new_block(&dn);
 662
 663         f2fs_put_dnode(&dn);
 664         if (err)
 665                 goto err;
 666
 667         mutex_unlock_op(sbi, ilock);
 668
 669         if ((len == PAGE_CACHE_SIZE) || PageUptodate(page))
 670                 return 0;
 671
 672         if ((pos & PAGE_CACHE_MASK) >= i_size_read(inode)) {
 673                 unsigned start = pos & (PAGE_CACHE_SIZE - 1);
 674                 unsigned end = start + len;
 675
 676                 /* Reading beyond i_size is simple: memset to zero */
 677                 zero_user_segments(page, 0, start, end, PAGE_CACHE_SIZE);
 678                 goto out;
 679         }
 680
 681         if (dn.data_blkaddr == NEW_ADDR) {
 682                 zero_user_segment(page, 0, PAGE_CACHE_SIZE);
 683         } else {
 684                 err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
 685                 if (err)
 686                         return err;
 687                 lock_page(page);
 688                 if (!PageUptodate(page)) {
 689                         f2fs_put_page(page, 1);
 690                         return -EIO;
 691                 }
 692                 if (page->mapping != mapping) {
 693                         f2fs_put_page(page, 1);
 694                         goto repeat;
 695                 }
 696         }
 697 out:
 698         SetPageUptodate(page);
 699         clear_cold_data(page);
 700         return 0;
 701
 702 err:
 703         mutex_unlock_op(sbi, ilock);
 704         f2fs_put_page(page, 1);
 705         return err;
 706 }
 707
 708 static int f2fs_write_end(struct file *file,
 709                         struct address_space *mapping,
 710                         loff_t pos, unsigned len, unsigned copied,
 711                         struct page *page, void *fsdata)
 712 {
 713         struct inode *inode = page->mapping->host;
 714
 715         SetPageUptodate(page);
 716         set_page_dirty(page);
 717
 718         if (pos + copied > i_size_read(inode)) {
 719                 i_size_write(inode, pos + copied);
 720                 mark_inode_dirty(inode);
 721                 update_inode_page(inode);
 722         }
 723
 724         unlock_page(page);
 725         page_cache_release(page);
 726         return copied;
 727 }
 728
 729 static ssize_t f2fs_direct_IO(int rw, struct kiocb *iocb,
 730                 const struct iovec *iov, loff_t offset, unsigned long nr_segs)
 731 {
 732         struct file *file = iocb->ki_filp;
 733         struct inode *inode = file->f_mapping->host;
 734
 735         if (rw == WRITE)
 736                 return 0;
 737
 738         /* Needs synchronization with the cleaner */
 739         return blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
 740                                                   get_data_block_ro);
 741 }
 742
 743 static void f2fs_invalidate_data_page(struct page *page, unsigned int offset,
 744                                       unsigned int length)
 745 {
 746         struct inode *inode = page->mapping->host;
 747         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 748         if (S_ISDIR(inode->i_mode) && PageDirty(page)) {
 749                 dec_page_count(sbi, F2FS_DIRTY_DENTS);
 750                 inode_dec_dirty_dents(inode);
 751         }
 752         ClearPagePrivate(page);
 753 }
 754
 755 static int f2fs_release_data_page(struct page *page, gfp_t wait)
 756 {
 757         ClearPagePrivate(page);
 758         return 1;
 759 }
 760
 761 static int f2fs_set_data_page_dirty(struct page *page)
 762 {
 763         struct address_space *mapping = page->mapping;
 764         struct inode *inode = mapping->host;
 765
 766         SetPageUptodate(page);
 767         if (!PageDirty(page)) {
 768                 __set_page_dirty_nobuffers(page);
 769                 set_dirty_dir_page(inode, page);
 770                 return 1;
 771         }
 772         return 0;
 773 }
 774
 775 static sector_t f2fs_bmap(struct address_space *mapping, sector_t block)
 776 {
 777         return generic_block_bmap(mapping, block, get_data_block_ro);
 778 }
 779
 780 const struct address_space_operations f2fs_dblock_aops = {
 781         .readpage       = f2fs_read_data_page,
 782         .readpages      = f2fs_read_data_pages,
 783         .writepage      = f2fs_write_data_page,
 784         .writepages     = f2fs_write_data_pages,
 785         .write_begin    = f2fs_write_begin,
 786         .write_end      = f2fs_write_end,
 787         .set_page_dirty = f2fs_set_data_page_dirty,
 788         .invalidatepage = f2fs_invalidate_data_page,
 789         .releasepage    = f2fs_release_data_page,
 790         .direct_IO      = f2fs_direct_IO,
 791         .bmap           = f2fs_bmap,
 792 };