linux/fs/ext4/inode.c
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   1/*
   2 *  linux/fs/ext4/inode.c
   3 *
   4 * Copyright (C) 1992, 1993, 1994, 1995
   5 * Remy Card (card@masi.ibp.fr)
   6 * Laboratoire MASI - Institut Blaise Pascal
   7 * Universite Pierre et Marie Curie (Paris VI)
   8 *
   9 *  from
  10 *
  11 *  linux/fs/minix/inode.c
  12 *
  13 *  Copyright (C) 1991, 1992  Linus Torvalds
  14 *
  15 *  64-bit file support on 64-bit platforms by Jakub Jelinek
  16 *      (jj@sunsite.ms.mff.cuni.cz)
  17 *
  18 *  Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
  19 */
  20
  21#include <linux/fs.h>
  22#include <linux/time.h>
  23#include <linux/jbd2.h>
  24#include <linux/highuid.h>
  25#include <linux/pagemap.h>
  26#include <linux/quotaops.h>
  27#include <linux/string.h>
  28#include <linux/buffer_head.h>
  29#include <linux/writeback.h>
  30#include <linux/pagevec.h>
  31#include <linux/mpage.h>
  32#include <linux/namei.h>
  33#include <linux/uio.h>
  34#include <linux/bio.h>
  35#include <linux/workqueue.h>
  36#include <linux/kernel.h>
  37#include <linux/printk.h>
  38#include <linux/slab.h>
  39#include <linux/ratelimit.h>
  40
  41#include "ext4_jbd2.h"
  42#include "xattr.h"
  43#include "acl.h"
  44#include "truncate.h"
  45
  46#include <trace/events/ext4.h>
  47
  48#define MPAGE_DA_EXTENT_TAIL 0x01
  49
  50static __u32 ext4_inode_csum(struct inode *inode, struct ext4_inode *raw,
  51                              struct ext4_inode_info *ei)
  52{
  53        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  54        __u16 csum_lo;
  55        __u16 csum_hi = 0;
  56        __u32 csum;
  57
  58        csum_lo = raw->i_checksum_lo;
  59        raw->i_checksum_lo = 0;
  60        if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
  61            EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) {
  62                csum_hi = raw->i_checksum_hi;
  63                raw->i_checksum_hi = 0;
  64        }
  65
  66        csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw,
  67                           EXT4_INODE_SIZE(inode->i_sb));
  68
  69        raw->i_checksum_lo = csum_lo;
  70        if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
  71            EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
  72                raw->i_checksum_hi = csum_hi;
  73
  74        return csum;
  75}
  76
  77static int ext4_inode_csum_verify(struct inode *inode, struct ext4_inode *raw,
  78                                  struct ext4_inode_info *ei)
  79{
  80        __u32 provided, calculated;
  81
  82        if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
  83            cpu_to_le32(EXT4_OS_LINUX) ||
  84            !EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
  85                EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
  86                return 1;
  87
  88        provided = le16_to_cpu(raw->i_checksum_lo);
  89        calculated = ext4_inode_csum(inode, raw, ei);
  90        if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
  91            EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
  92                provided |= ((__u32)le16_to_cpu(raw->i_checksum_hi)) << 16;
  93        else
  94                calculated &= 0xFFFF;
  95
  96        return provided == calculated;
  97}
  98
  99static void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
 100                                struct ext4_inode_info *ei)
 101{
 102        __u32 csum;
 103
 104        if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
 105            cpu_to_le32(EXT4_OS_LINUX) ||
 106            !EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
 107                EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
 108                return;
 109
 110        csum = ext4_inode_csum(inode, raw, ei);
 111        raw->i_checksum_lo = cpu_to_le16(csum & 0xFFFF);
 112        if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
 113            EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
 114                raw->i_checksum_hi = cpu_to_le16(csum >> 16);
 115}
 116
 117static inline int ext4_begin_ordered_truncate(struct inode *inode,
 118                                              loff_t new_size)
 119{
 120        trace_ext4_begin_ordered_truncate(inode, new_size);
 121        /*
 122         * If jinode is zero, then we never opened the file for
 123         * writing, so there's no need to call
 124         * jbd2_journal_begin_ordered_truncate() since there's no
 125         * outstanding writes we need to flush.
 126         */
 127        if (!EXT4_I(inode)->jinode)
 128                return 0;
 129        return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
 130                                                   EXT4_I(inode)->jinode,
 131                                                   new_size);
 132}
 133
 134static void ext4_invalidatepage(struct page *page, unsigned long offset);
 135static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
 136                                   struct buffer_head *bh_result, int create);
 137static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode);
 138static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate);
 139static int __ext4_journalled_writepage(struct page *page, unsigned int len);
 140static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
 141static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle,
 142                struct inode *inode, struct page *page, loff_t from,
 143                loff_t length, int flags);
 144
 145/*
 146 * Test whether an inode is a fast symlink.
 147 */
 148static int ext4_inode_is_fast_symlink(struct inode *inode)
 149{
 150        int ea_blocks = EXT4_I(inode)->i_file_acl ?
 151                (inode->i_sb->s_blocksize >> 9) : 0;
 152
 153        return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
 154}
 155
 156/*
 157 * Restart the transaction associated with *handle.  This does a commit,
 158 * so before we call here everything must be consistently dirtied against
 159 * this transaction.
 160 */
 161int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode,
 162                                 int nblocks)
 163{
 164        int ret;
 165
 166        /*
 167         * Drop i_data_sem to avoid deadlock with ext4_map_blocks.  At this
 168         * moment, get_block can be called only for blocks inside i_size since
 169         * page cache has been already dropped and writes are blocked by
 170         * i_mutex. So we can safely drop the i_data_sem here.
 171         */
 172        BUG_ON(EXT4_JOURNAL(inode) == NULL);
 173        jbd_debug(2, "restarting handle %p\n", handle);
 174        up_write(&EXT4_I(inode)->i_data_sem);
 175        ret = ext4_journal_restart(handle, nblocks);
 176        down_write(&EXT4_I(inode)->i_data_sem);
 177        ext4_discard_preallocations(inode);
 178
 179        return ret;
 180}
 181
 182/*
 183 * Called at the last iput() if i_nlink is zero.
 184 */
 185void ext4_evict_inode(struct inode *inode)
 186{
 187        handle_t *handle;
 188        int err;
 189
 190        trace_ext4_evict_inode(inode);
 191
 192        ext4_ioend_wait(inode);
 193
 194        if (inode->i_nlink) {
 195                /*
 196                 * When journalling data dirty buffers are tracked only in the
 197                 * journal. So although mm thinks everything is clean and
 198                 * ready for reaping the inode might still have some pages to
 199                 * write in the running transaction or waiting to be
 200                 * checkpointed. Thus calling jbd2_journal_invalidatepage()
 201                 * (via truncate_inode_pages()) to discard these buffers can
 202                 * cause data loss. Also even if we did not discard these
 203                 * buffers, we would have no way to find them after the inode
 204                 * is reaped and thus user could see stale data if he tries to
 205                 * read them before the transaction is checkpointed. So be
 206                 * careful and force everything to disk here... We use
 207                 * ei->i_datasync_tid to store the newest transaction
 208                 * containing inode's data.
 209                 *
 210                 * Note that directories do not have this problem because they
 211                 * don't use page cache.
 212                 */
 213                if (ext4_should_journal_data(inode) &&
 214                    (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode))) {
 215                        journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
 216                        tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
 217
 218                        jbd2_log_start_commit(journal, commit_tid);
 219                        jbd2_log_wait_commit(journal, commit_tid);
 220                        filemap_write_and_wait(&inode->i_data);
 221                }
 222                truncate_inode_pages(&inode->i_data, 0);
 223                goto no_delete;
 224        }
 225
 226        if (!is_bad_inode(inode))
 227                dquot_initialize(inode);
 228
 229        if (ext4_should_order_data(inode))
 230                ext4_begin_ordered_truncate(inode, 0);
 231        truncate_inode_pages(&inode->i_data, 0);
 232
 233        if (is_bad_inode(inode))
 234                goto no_delete;
 235
 236        /*
 237         * Protect us against freezing - iput() caller didn't have to have any
 238         * protection against it
 239         */
 240        sb_start_intwrite(inode->i_sb);
 241        handle = ext4_journal_start(inode, ext4_blocks_for_truncate(inode)+3);
 242        if (IS_ERR(handle)) {
 243                ext4_std_error(inode->i_sb, PTR_ERR(handle));
 244                /*
 245                 * If we're going to skip the normal cleanup, we still need to
 246                 * make sure that the in-core orphan linked list is properly
 247                 * cleaned up.
 248                 */
 249                ext4_orphan_del(NULL, inode);
 250                sb_end_intwrite(inode->i_sb);
 251                goto no_delete;
 252        }
 253
 254        if (IS_SYNC(inode))
 255                ext4_handle_sync(handle);
 256        inode->i_size = 0;
 257        err = ext4_mark_inode_dirty(handle, inode);
 258        if (err) {
 259                ext4_warning(inode->i_sb,
 260                             "couldn't mark inode dirty (err %d)", err);
 261                goto stop_handle;
 262        }
 263        if (inode->i_blocks)
 264                ext4_truncate(inode);
 265
 266        /*
 267         * ext4_ext_truncate() doesn't reserve any slop when it
 268         * restarts journal transactions; therefore there may not be
 269         * enough credits left in the handle to remove the inode from
 270         * the orphan list and set the dtime field.
 271         */
 272        if (!ext4_handle_has_enough_credits(handle, 3)) {
 273                err = ext4_journal_extend(handle, 3);
 274                if (err > 0)
 275                        err = ext4_journal_restart(handle, 3);
 276                if (err != 0) {
 277                        ext4_warning(inode->i_sb,
 278                                     "couldn't extend journal (err %d)", err);
 279                stop_handle:
 280                        ext4_journal_stop(handle);
 281                        ext4_orphan_del(NULL, inode);
 282                        sb_end_intwrite(inode->i_sb);
 283                        goto no_delete;
 284                }
 285        }
 286
 287        /*
 288         * Kill off the orphan record which ext4_truncate created.
 289         * AKPM: I think this can be inside the above `if'.
 290         * Note that ext4_orphan_del() has to be able to cope with the
 291         * deletion of a non-existent orphan - this is because we don't
 292         * know if ext4_truncate() actually created an orphan record.
 293         * (Well, we could do this if we need to, but heck - it works)
 294         */
 295        ext4_orphan_del(handle, inode);
 296        EXT4_I(inode)->i_dtime  = get_seconds();
 297
 298        /*
 299         * One subtle ordering requirement: if anything has gone wrong
 300         * (transaction abort, IO errors, whatever), then we can still
 301         * do these next steps (the fs will already have been marked as
 302         * having errors), but we can't free the inode if the mark_dirty
 303         * fails.
 304         */
 305        if (ext4_mark_inode_dirty(handle, inode))
 306                /* If that failed, just do the required in-core inode clear. */
 307                ext4_clear_inode(inode);
 308        else
 309                ext4_free_inode(handle, inode);
 310        ext4_journal_stop(handle);
 311        sb_end_intwrite(inode->i_sb);
 312        return;
 313no_delete:
 314        ext4_clear_inode(inode);        /* We must guarantee clearing of inode... */
 315}
 316
 317#ifdef CONFIG_QUOTA
 318qsize_t *ext4_get_reserved_space(struct inode *inode)
 319{
 320        return &EXT4_I(inode)->i_reserved_quota;
 321}
 322#endif
 323
 324/*
 325 * Calculate the number of metadata blocks need to reserve
 326 * to allocate a block located at @lblock
 327 */
 328static int ext4_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
 329{
 330        if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 331                return ext4_ext_calc_metadata_amount(inode, lblock);
 332
 333        return ext4_ind_calc_metadata_amount(inode, lblock);
 334}
 335
 336/*
 337 * Called with i_data_sem down, which is important since we can call
 338 * ext4_discard_preallocations() from here.
 339 */
 340void ext4_da_update_reserve_space(struct inode *inode,
 341                                        int used, int quota_claim)
 342{
 343        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 344        struct ext4_inode_info *ei = EXT4_I(inode);
 345
 346        spin_lock(&ei->i_block_reservation_lock);
 347        trace_ext4_da_update_reserve_space(inode, used, quota_claim);
 348        if (unlikely(used > ei->i_reserved_data_blocks)) {
 349                ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, used %d "
 350                         "with only %d reserved data blocks",
 351                         __func__, inode->i_ino, used,
 352                         ei->i_reserved_data_blocks);
 353                WARN_ON(1);
 354                used = ei->i_reserved_data_blocks;
 355        }
 356
 357        if (unlikely(ei->i_allocated_meta_blocks > ei->i_reserved_meta_blocks)) {
 358                ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, allocated %d "
 359                         "with only %d reserved metadata blocks\n", __func__,
 360                         inode->i_ino, ei->i_allocated_meta_blocks,
 361                         ei->i_reserved_meta_blocks);
 362                WARN_ON(1);
 363                ei->i_allocated_meta_blocks = ei->i_reserved_meta_blocks;
 364        }
 365
 366        /* Update per-inode reservations */
 367        ei->i_reserved_data_blocks -= used;
 368        ei->i_reserved_meta_blocks -= ei->i_allocated_meta_blocks;
 369        percpu_counter_sub(&sbi->s_dirtyclusters_counter,
 370                           used + ei->i_allocated_meta_blocks);
 371        ei->i_allocated_meta_blocks = 0;
 372
 373        if (ei->i_reserved_data_blocks == 0) {
 374                /*
 375                 * We can release all of the reserved metadata blocks
 376                 * only when we have written all of the delayed
 377                 * allocation blocks.
 378                 */
 379                percpu_counter_sub(&sbi->s_dirtyclusters_counter,
 380                                   ei->i_reserved_meta_blocks);
 381                ei->i_reserved_meta_blocks = 0;
 382                ei->i_da_metadata_calc_len = 0;
 383        }
 384        spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 385
 386        /* Update quota subsystem for data blocks */
 387        if (quota_claim)
 388                dquot_claim_block(inode, EXT4_C2B(sbi, used));
 389        else {
 390                /*
 391                 * We did fallocate with an offset that is already delayed
 392                 * allocated. So on delayed allocated writeback we should
 393                 * not re-claim the quota for fallocated blocks.
 394                 */
 395                dquot_release_reservation_block(inode, EXT4_C2B(sbi, used));
 396        }
 397
 398        /*
 399         * If we have done all the pending block allocations and if
 400         * there aren't any writers on the inode, we can discard the
 401         * inode's preallocations.
 402         */
 403        if ((ei->i_reserved_data_blocks == 0) &&
 404            (atomic_read(&inode->i_writecount) == 0))
 405                ext4_discard_preallocations(inode);
 406}
 407
 408static int __check_block_validity(struct inode *inode, const char *func,
 409                                unsigned int line,
 410                                struct ext4_map_blocks *map)
 411{
 412        if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk,
 413                                   map->m_len)) {
 414                ext4_error_inode(inode, func, line, map->m_pblk,
 415                                 "lblock %lu mapped to illegal pblock "
 416                                 "(length %d)", (unsigned long) map->m_lblk,
 417                                 map->m_len);
 418                return -EIO;
 419        }
 420        return 0;
 421}
 422
 423#define check_block_validity(inode, map)        \
 424        __check_block_validity((inode), __func__, __LINE__, (map))
 425
 426/*
 427 * Return the number of contiguous dirty pages in a given inode
 428 * starting at page frame idx.
 429 */
 430static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx,
 431                                    unsigned int max_pages)
 432{
 433        struct address_space *mapping = inode->i_mapping;
 434        pgoff_t index;
 435        struct pagevec pvec;
 436        pgoff_t num = 0;
 437        int i, nr_pages, done = 0;
 438
 439        if (max_pages == 0)
 440                return 0;
 441        pagevec_init(&pvec, 0);
 442        while (!done) {
 443                index = idx;
 444                nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
 445                                              PAGECACHE_TAG_DIRTY,
 446                                              (pgoff_t)PAGEVEC_SIZE);
 447                if (nr_pages == 0)
 448                        break;
 449                for (i = 0; i < nr_pages; i++) {
 450                        struct page *page = pvec.pages[i];
 451                        struct buffer_head *bh, *head;
 452
 453                        lock_page(page);
 454                        if (unlikely(page->mapping != mapping) ||
 455                            !PageDirty(page) ||
 456                            PageWriteback(page) ||
 457                            page->index != idx) {
 458                                done = 1;
 459                                unlock_page(page);
 460                                break;
 461                        }
 462                        if (page_has_buffers(page)) {
 463                                bh = head = page_buffers(page);
 464                                do {
 465                                        if (!buffer_delay(bh) &&
 466                                            !buffer_unwritten(bh))
 467                                                done = 1;
 468                                        bh = bh->b_this_page;
 469                                } while (!done && (bh != head));
 470                        }
 471                        unlock_page(page);
 472                        if (done)
 473                                break;
 474                        idx++;
 475                        num++;
 476                        if (num >= max_pages) {
 477                                done = 1;
 478                                break;
 479                        }
 480                }
 481                pagevec_release(&pvec);
 482        }
 483        return num;
 484}
 485
 486/*
 487 * Sets the BH_Da_Mapped bit on the buffer heads corresponding to the given map.
 488 */
 489static void set_buffers_da_mapped(struct inode *inode,
 490                                   struct ext4_map_blocks *map)
 491{
 492        struct address_space *mapping = inode->i_mapping;
 493        struct pagevec pvec;
 494        int i, nr_pages;
 495        pgoff_t index, end;
 496
 497        index = map->m_lblk >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
 498        end = (map->m_lblk + map->m_len - 1) >>
 499                (PAGE_CACHE_SHIFT - inode->i_blkbits);
 500
 501        pagevec_init(&pvec, 0);
 502        while (index <= end) {
 503                nr_pages = pagevec_lookup(&pvec, mapping, index,
 504                                          min(end - index + 1,
 505                                              (pgoff_t)PAGEVEC_SIZE));
 506                if (nr_pages == 0)
 507                        break;
 508                for (i = 0; i < nr_pages; i++) {
 509                        struct page *page = pvec.pages[i];
 510                        struct buffer_head *bh, *head;
 511
 512                        if (unlikely(page->mapping != mapping) ||
 513                            !PageDirty(page))
 514                                break;
 515
 516                        if (page_has_buffers(page)) {
 517                                bh = head = page_buffers(page);
 518                                do {
 519                                        set_buffer_da_mapped(bh);
 520                                        bh = bh->b_this_page;
 521                                } while (bh != head);
 522                        }
 523                        index++;
 524                }
 525                pagevec_release(&pvec);
 526        }
 527}
 528
 529/*
 530 * The ext4_map_blocks() function tries to look up the requested blocks,
 531 * and returns if the blocks are already mapped.
 532 *
 533 * Otherwise it takes the write lock of the i_data_sem and allocate blocks
 534 * and store the allocated blocks in the result buffer head and mark it
 535 * mapped.
 536 *
 537 * If file type is extents based, it will call ext4_ext_map_blocks(),
 538 * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
 539 * based files
 540 *
 541 * On success, it returns the number of blocks being mapped or allocate.
 542 * if create==0 and the blocks are pre-allocated and uninitialized block,
 543 * the result buffer head is unmapped. If the create ==1, it will make sure
 544 * the buffer head is mapped.
 545 *
 546 * It returns 0 if plain look up failed (blocks have not been allocated), in
 547 * that case, buffer head is unmapped
 548 *
 549 * It returns the error in case of allocation failure.
 550 */
 551int ext4_map_blocks(handle_t *handle, struct inode *inode,
 552                    struct ext4_map_blocks *map, int flags)
 553{
 554        int retval;
 555
 556        map->m_flags = 0;
 557        ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u,"
 558                  "logical block %lu\n", inode->i_ino, flags, map->m_len,
 559                  (unsigned long) map->m_lblk);
 560        /*
 561         * Try to see if we can get the block without requesting a new
 562         * file system block.
 563         */
 564        if (!(flags & EXT4_GET_BLOCKS_NO_LOCK))
 565                down_read((&EXT4_I(inode)->i_data_sem));
 566        if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
 567                retval = ext4_ext_map_blocks(handle, inode, map, flags &
 568                                             EXT4_GET_BLOCKS_KEEP_SIZE);
 569        } else {
 570                retval = ext4_ind_map_blocks(handle, inode, map, flags &
 571                                             EXT4_GET_BLOCKS_KEEP_SIZE);
 572        }
 573        if (!(flags & EXT4_GET_BLOCKS_NO_LOCK))
 574                up_read((&EXT4_I(inode)->i_data_sem));
 575
 576        if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
 577                int ret = check_block_validity(inode, map);
 578                if (ret != 0)
 579                        return ret;
 580        }
 581
 582        /* If it is only a block(s) look up */
 583        if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
 584                return retval;
 585
 586        /*
 587         * Returns if the blocks have already allocated
 588         *
 589         * Note that if blocks have been preallocated
 590         * ext4_ext_get_block() returns the create = 0
 591         * with buffer head unmapped.
 592         */
 593        if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
 594                return retval;
 595
 596        /*
 597         * When we call get_blocks without the create flag, the
 598         * BH_Unwritten flag could have gotten set if the blocks
 599         * requested were part of a uninitialized extent.  We need to
 600         * clear this flag now that we are committed to convert all or
 601         * part of the uninitialized extent to be an initialized
 602         * extent.  This is because we need to avoid the combination
 603         * of BH_Unwritten and BH_Mapped flags being simultaneously
 604         * set on the buffer_head.
 605         */
 606        map->m_flags &= ~EXT4_MAP_UNWRITTEN;
 607
 608        /*
 609         * New blocks allocate and/or writing to uninitialized extent
 610         * will possibly result in updating i_data, so we take
 611         * the write lock of i_data_sem, and call get_blocks()
 612         * with create == 1 flag.
 613         */
 614        down_write((&EXT4_I(inode)->i_data_sem));
 615
 616        /*
 617         * if the caller is from delayed allocation writeout path
 618         * we have already reserved fs blocks for allocation
 619         * let the underlying get_block() function know to
 620         * avoid double accounting
 621         */
 622        if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
 623                ext4_set_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED);
 624        /*
 625         * We need to check for EXT4 here because migrate
 626         * could have changed the inode type in between
 627         */
 628        if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
 629                retval = ext4_ext_map_blocks(handle, inode, map, flags);
 630        } else {
 631                retval = ext4_ind_map_blocks(handle, inode, map, flags);
 632
 633                if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
 634                        /*
 635                         * We allocated new blocks which will result in
 636                         * i_data's format changing.  Force the migrate
 637                         * to fail by clearing migrate flags
 638                         */
 639                        ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
 640                }
 641
 642                /*
 643                 * Update reserved blocks/metadata blocks after successful
 644                 * block allocation which had been deferred till now. We don't
 645                 * support fallocate for non extent files. So we can update
 646                 * reserve space here.
 647                 */
 648                if ((retval > 0) &&
 649                        (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
 650                        ext4_da_update_reserve_space(inode, retval, 1);
 651        }
 652        if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
 653                ext4_clear_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED);
 654
 655                /* If we have successfully mapped the delayed allocated blocks,
 656                 * set the BH_Da_Mapped bit on them. Its important to do this
 657                 * under the protection of i_data_sem.
 658                 */
 659                if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
 660                        set_buffers_da_mapped(inode, map);
 661        }
 662
 663        up_write((&EXT4_I(inode)->i_data_sem));
 664        if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
 665                int ret = check_block_validity(inode, map);
 666                if (ret != 0)
 667                        return ret;
 668        }
 669        return retval;
 670}
 671
 672/* Maximum number of blocks we map for direct IO at once. */
 673#define DIO_MAX_BLOCKS 4096
 674
 675static int _ext4_get_block(struct inode *inode, sector_t iblock,
 676                           struct buffer_head *bh, int flags)
 677{
 678        handle_t *handle = ext4_journal_current_handle();
 679        struct ext4_map_blocks map;
 680        int ret = 0, started = 0;
 681        int dio_credits;
 682
 683        map.m_lblk = iblock;
 684        map.m_len = bh->b_size >> inode->i_blkbits;
 685
 686        if (flags && !handle) {
 687                /* Direct IO write... */
 688                if (map.m_len > DIO_MAX_BLOCKS)
 689                        map.m_len = DIO_MAX_BLOCKS;
 690                dio_credits = ext4_chunk_trans_blocks(inode, map.m_len);
 691                handle = ext4_journal_start(inode, dio_credits);
 692                if (IS_ERR(handle)) {
 693                        ret = PTR_ERR(handle);
 694                        return ret;
 695                }
 696                started = 1;
 697        }
 698
 699        ret = ext4_map_blocks(handle, inode, &map, flags);
 700        if (ret > 0) {
 701                map_bh(bh, inode->i_sb, map.m_pblk);
 702                bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
 703                bh->b_size = inode->i_sb->s_blocksize * map.m_len;
 704                ret = 0;
 705        }
 706        if (started)
 707                ext4_journal_stop(handle);
 708        return ret;
 709}
 710
 711int ext4_get_block(struct inode *inode, sector_t iblock,
 712                   struct buffer_head *bh, int create)
 713{
 714        return _ext4_get_block(inode, iblock, bh,
 715                               create ? EXT4_GET_BLOCKS_CREATE : 0);
 716}
 717
 718/*
 719 * `handle' can be NULL if create is zero
 720 */
 721struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
 722                                ext4_lblk_t block, int create, int *errp)
 723{
 724        struct ext4_map_blocks map;
 725        struct buffer_head *bh;
 726        int fatal = 0, err;
 727
 728        J_ASSERT(handle != NULL || create == 0);
 729
 730        map.m_lblk = block;
 731        map.m_len = 1;
 732        err = ext4_map_blocks(handle, inode, &map,
 733                              create ? EXT4_GET_BLOCKS_CREATE : 0);
 734
 735        if (err < 0)
 736                *errp = err;
 737        if (err <= 0)
 738                return NULL;
 739        *errp = 0;
 740
 741        bh = sb_getblk(inode->i_sb, map.m_pblk);
 742        if (!bh) {
 743                *errp = -EIO;
 744                return NULL;
 745        }
 746        if (map.m_flags & EXT4_MAP_NEW) {
 747                J_ASSERT(create != 0);
 748                J_ASSERT(handle != NULL);
 749
 750                /*
 751                 * Now that we do not always journal data, we should
 752                 * keep in mind whether this should always journal the
 753                 * new buffer as metadata.  For now, regular file
 754                 * writes use ext4_get_block instead, so it's not a
 755                 * problem.
 756                 */
 757                lock_buffer(bh);
 758                BUFFER_TRACE(bh, "call get_create_access");
 759                fatal = ext4_journal_get_create_access(handle, bh);
 760                if (!fatal && !buffer_uptodate(bh)) {
 761                        memset(bh->b_data, 0, inode->i_sb->s_blocksize);
 762                        set_buffer_uptodate(bh);
 763                }
 764                unlock_buffer(bh);
 765                BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
 766                err = ext4_handle_dirty_metadata(handle, inode, bh);
 767                if (!fatal)
 768                        fatal = err;
 769        } else {
 770                BUFFER_TRACE(bh, "not a new buffer");
 771        }
 772        if (fatal) {
 773                *errp = fatal;
 774                brelse(bh);
 775                bh = NULL;
 776        }
 777        return bh;
 778}
 779
 780struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
 781                               ext4_lblk_t block, int create, int *err)
 782{
 783        struct buffer_head *bh;
 784
 785        bh = ext4_getblk(handle, inode, block, create, err);
 786        if (!bh)
 787                return bh;
 788        if (buffer_uptodate(bh))
 789                return bh;
 790        ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
 791        wait_on_buffer(bh);
 792        if (buffer_uptodate(bh))
 793                return bh;
 794        put_bh(bh);
 795        *err = -EIO;
 796        return NULL;
 797}
 798
 799static int walk_page_buffers(handle_t *handle,
 800                             struct buffer_head *head,
 801                             unsigned from,
 802                             unsigned to,
 803                             int *partial,
 804                             int (*fn)(handle_t *handle,
 805                                       struct buffer_head *bh))
 806{
 807        struct buffer_head *bh;
 808        unsigned block_start, block_end;
 809        unsigned blocksize = head->b_size;
 810        int err, ret = 0;
 811        struct buffer_head *next;
 812
 813        for (bh = head, block_start = 0;
 814             ret == 0 && (bh != head || !block_start);
 815             block_start = block_end, bh = next) {
 816                next = bh->b_this_page;
 817                block_end = block_start + blocksize;
 818                if (block_end <= from || block_start >= to) {
 819                        if (partial && !buffer_uptodate(bh))
 820                                *partial = 1;
 821                        continue;
 822                }
 823                err = (*fn)(handle, bh);
 824                if (!ret)
 825                        ret = err;
 826        }
 827        return ret;
 828}
 829
 830/*
 831 * To preserve ordering, it is essential that the hole instantiation and
 832 * the data write be encapsulated in a single transaction.  We cannot
 833 * close off a transaction and start a new one between the ext4_get_block()
 834 * and the commit_write().  So doing the jbd2_journal_start at the start of
 835 * prepare_write() is the right place.
 836 *
 837 * Also, this function can nest inside ext4_writepage() ->
 838 * block_write_full_page(). In that case, we *know* that ext4_writepage()
 839 * has generated enough buffer credits to do the whole page.  So we won't
 840 * block on the journal in that case, which is good, because the caller may
 841 * be PF_MEMALLOC.
 842 *
 843 * By accident, ext4 can be reentered when a transaction is open via
 844 * quota file writes.  If we were to commit the transaction while thus
 845 * reentered, there can be a deadlock - we would be holding a quota
 846 * lock, and the commit would never complete if another thread had a
 847 * transaction open and was blocking on the quota lock - a ranking
 848 * violation.
 849 *
 850 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
 851 * will _not_ run commit under these circumstances because handle->h_ref
 852 * is elevated.  We'll still have enough credits for the tiny quotafile
 853 * write.
 854 */
 855static int do_journal_get_write_access(handle_t *handle,
 856                                       struct buffer_head *bh)
 857{
 858        int dirty = buffer_dirty(bh);
 859        int ret;
 860
 861        if (!buffer_mapped(bh) || buffer_freed(bh))
 862                return 0;
 863        /*
 864         * __block_write_begin() could have dirtied some buffers. Clean
 865         * the dirty bit as jbd2_journal_get_write_access() could complain
 866         * otherwise about fs integrity issues. Setting of the dirty bit
 867         * by __block_write_begin() isn't a real problem here as we clear
 868         * the bit before releasing a page lock and thus writeback cannot
 869         * ever write the buffer.
 870         */
 871        if (dirty)
 872                clear_buffer_dirty(bh);
 873        ret = ext4_journal_get_write_access(handle, bh);
 874        if (!ret && dirty)
 875                ret = ext4_handle_dirty_metadata(handle, NULL, bh);
 876        return ret;
 877}
 878
 879static int ext4_get_block_write(struct inode *inode, sector_t iblock,
 880                   struct buffer_head *bh_result, int create);
 881static int ext4_write_begin(struct file *file, struct address_space *mapping,
 882                            loff_t pos, unsigned len, unsigned flags,
 883                            struct page **pagep, void **fsdata)
 884{
 885        struct inode *inode = mapping->host;
 886        int ret, needed_blocks;
 887        handle_t *handle;
 888        int retries = 0;
 889        struct page *page;
 890        pgoff_t index;
 891        unsigned from, to;
 892
 893        trace_ext4_write_begin(inode, pos, len, flags);
 894        /*
 895         * Reserve one block more for addition to orphan list in case
 896         * we allocate blocks but write fails for some reason
 897         */
 898        needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
 899        index = pos >> PAGE_CACHE_SHIFT;
 900        from = pos & (PAGE_CACHE_SIZE - 1);
 901        to = from + len;
 902
 903retry:
 904        handle = ext4_journal_start(inode, needed_blocks);
 905        if (IS_ERR(handle)) {
 906                ret = PTR_ERR(handle);
 907                goto out;
 908        }
 909
 910        /* We cannot recurse into the filesystem as the transaction is already
 911         * started */
 912        flags |= AOP_FLAG_NOFS;
 913
 914        page = grab_cache_page_write_begin(mapping, index, flags);
 915        if (!page) {
 916                ext4_journal_stop(handle);
 917                ret = -ENOMEM;
 918                goto out;
 919        }
 920        *pagep = page;
 921
 922        if (ext4_should_dioread_nolock(inode))
 923                ret = __block_write_begin(page, pos, len, ext4_get_block_write);
 924        else
 925                ret = __block_write_begin(page, pos, len, ext4_get_block);
 926
 927        if (!ret && ext4_should_journal_data(inode)) {
 928                ret = walk_page_buffers(handle, page_buffers(page),
 929                                from, to, NULL, do_journal_get_write_access);
 930        }
 931
 932        if (ret) {
 933                unlock_page(page);
 934                page_cache_release(page);
 935                /*
 936                 * __block_write_begin may have instantiated a few blocks
 937                 * outside i_size.  Trim these off again. Don't need
 938                 * i_size_read because we hold i_mutex.
 939                 *
 940                 * Add inode to orphan list in case we crash before
 941                 * truncate finishes
 942                 */
 943                if (pos + len > inode->i_size && ext4_can_truncate(inode))
 944                        ext4_orphan_add(handle, inode);
 945
 946                ext4_journal_stop(handle);
 947                if (pos + len > inode->i_size) {
 948                        ext4_truncate_failed_write(inode);
 949                        /*
 950                         * If truncate failed early the inode might
 951                         * still be on the orphan list; we need to
 952                         * make sure the inode is removed from the
 953                         * orphan list in that case.
 954                         */
 955                        if (inode->i_nlink)
 956                                ext4_orphan_del(NULL, inode);
 957                }
 958        }
 959
 960        if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
 961                goto retry;
 962out:
 963        return ret;
 964}
 965
 966/* For write_end() in data=journal mode */
 967static int write_end_fn(handle_t *handle, struct buffer_head *bh)
 968{
 969        if (!buffer_mapped(bh) || buffer_freed(bh))
 970                return 0;
 971        set_buffer_uptodate(bh);
 972        return ext4_handle_dirty_metadata(handle, NULL, bh);
 973}
 974
 975static int ext4_generic_write_end(struct file *file,
 976                                  struct address_space *mapping,
 977                                  loff_t pos, unsigned len, unsigned copied,
 978                                  struct page *page, void *fsdata)
 979{
 980        int i_size_changed = 0;
 981        struct inode *inode = mapping->host;
 982        handle_t *handle = ext4_journal_current_handle();
 983
 984        copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
 985
 986        /*
 987         * No need to use i_size_read() here, the i_size
 988         * cannot change under us because we hold i_mutex.
 989         *
 990         * But it's important to update i_size while still holding page lock:
 991         * page writeout could otherwise come in and zero beyond i_size.
 992         */
 993        if (pos + copied > inode->i_size) {
 994                i_size_write(inode, pos + copied);
 995                i_size_changed = 1;
 996        }
 997
 998        if (pos + copied >  EXT4_I(inode)->i_disksize) {
 999                /* We need to mark inode dirty even if
1000                 * new_i_size is less that inode->i_size
1001                 * bu greater than i_disksize.(hint delalloc)
1002                 */
1003                ext4_update_i_disksize(inode, (pos + copied));
1004                i_size_changed = 1;
1005        }
1006        unlock_page(page);
1007        page_cache_release(page);
1008
1009        /*
1010         * Don't mark the inode dirty under page lock. First, it unnecessarily
1011         * makes the holding time of page lock longer. Second, it forces lock
1012         * ordering of page lock and transaction start for journaling
1013         * filesystems.
1014         */
1015        if (i_size_changed)
1016                ext4_mark_inode_dirty(handle, inode);
1017
1018        return copied;
1019}
1020
1021/*
1022 * We need to pick up the new inode size which generic_commit_write gave us
1023 * `file' can be NULL - eg, when called from page_symlink().
1024 *
1025 * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1026 * buffers are managed internally.
1027 */
1028static int ext4_ordered_write_end(struct file *file,
1029                                  struct address_space *mapping,
1030                                  loff_t pos, unsigned len, unsigned copied,
1031                                  struct page *page, void *fsdata)
1032{
1033        handle_t *handle = ext4_journal_current_handle();
1034        struct inode *inode = mapping->host;
1035        int ret = 0, ret2;
1036
1037        trace_ext4_ordered_write_end(inode, pos, len, copied);
1038        ret = ext4_jbd2_file_inode(handle, inode);
1039
1040        if (ret == 0) {
1041                ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
1042                                                        page, fsdata);
1043                copied = ret2;
1044                if (pos + len > inode->i_size && ext4_can_truncate(inode))
1045                        /* if we have allocated more blocks and copied
1046                         * less. We will have blocks allocated outside
1047                         * inode->i_size. So truncate them
1048                         */
1049                        ext4_orphan_add(handle, inode);
1050                if (ret2 < 0)
1051                        ret = ret2;
1052        } else {
1053                unlock_page(page);
1054                page_cache_release(page);
1055        }
1056
1057        ret2 = ext4_journal_stop(handle);
1058        if (!ret)
1059                ret = ret2;
1060
1061        if (pos + len > inode->i_size) {
1062                ext4_truncate_failed_write(inode);
1063                /*
1064                 * If truncate failed early the inode might still be
1065                 * on the orphan list; we need to make sure the inode
1066                 * is removed from the orphan list in that case.
1067                 */
1068                if (inode->i_nlink)
1069                        ext4_orphan_del(NULL, inode);
1070        }
1071
1072
1073        return ret ? ret : copied;
1074}
1075
1076static int ext4_writeback_write_end(struct file *file,
1077                                    struct address_space *mapping,
1078                                    loff_t pos, unsigned len, unsigned copied,
1079                                    struct page *page, void *fsdata)
1080{
1081        handle_t *handle = ext4_journal_current_handle();
1082        struct inode *inode = mapping->host;
1083        int ret = 0, ret2;
1084
1085        trace_ext4_writeback_write_end(inode, pos, len, copied);
1086        ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
1087                                                        page, fsdata);
1088        copied = ret2;
1089        if (pos + len > inode->i_size && ext4_can_truncate(inode))
1090                /* if we have allocated more blocks and copied
1091                 * less. We will have blocks allocated outside
1092                 * inode->i_size. So truncate them
1093                 */
1094                ext4_orphan_add(handle, inode);
1095
1096        if (ret2 < 0)
1097                ret = ret2;
1098
1099        ret2 = ext4_journal_stop(handle);
1100        if (!ret)
1101                ret = ret2;
1102
1103        if (pos + len > inode->i_size) {
1104                ext4_truncate_failed_write(inode);
1105                /*
1106                 * If truncate failed early the inode might still be
1107                 * on the orphan list; we need to make sure the inode
1108                 * is removed from the orphan list in that case.
1109                 */
1110                if (inode->i_nlink)
1111                        ext4_orphan_del(NULL, inode);
1112        }
1113
1114        return ret ? ret : copied;
1115}
1116
1117static int ext4_journalled_write_end(struct file *file,
1118                                     struct address_space *mapping,
1119                                     loff_t pos, unsigned len, unsigned copied,
1120                                     struct page *page, void *fsdata)
1121{
1122        handle_t *handle = ext4_journal_current_handle();
1123        struct inode *inode = mapping->host;
1124        int ret = 0, ret2;
1125        int partial = 0;
1126        unsigned from, to;
1127        loff_t new_i_size;
1128
1129        trace_ext4_journalled_write_end(inode, pos, len, copied);
1130        from = pos & (PAGE_CACHE_SIZE - 1);
1131        to = from + len;
1132
1133        BUG_ON(!ext4_handle_valid(handle));
1134
1135        if (copied < len) {
1136                if (!PageUptodate(page))
1137                        copied = 0;
1138                page_zero_new_buffers(page, from+copied, to);
1139        }
1140
1141        ret = walk_page_buffers(handle, page_buffers(page), from,
1142                                to, &partial, write_end_fn);
1143        if (!partial)
1144                SetPageUptodate(page);
1145        new_i_size = pos + copied;
1146        if (new_i_size > inode->i_size)
1147                i_size_write(inode, pos+copied);
1148        ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1149        EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1150        if (new_i_size > EXT4_I(inode)->i_disksize) {
1151                ext4_update_i_disksize(inode, new_i_size);
1152                ret2 = ext4_mark_inode_dirty(handle, inode);
1153                if (!ret)
1154                        ret = ret2;
1155        }
1156
1157        unlock_page(page);
1158        page_cache_release(page);
1159        if (pos + len > inode->i_size && ext4_can_truncate(inode))
1160                /* if we have allocated more blocks and copied
1161                 * less. We will have blocks allocated outside
1162                 * inode->i_size. So truncate them
1163                 */
1164                ext4_orphan_add(handle, inode);
1165
1166        ret2 = ext4_journal_stop(handle);
1167        if (!ret)
1168                ret = ret2;
1169        if (pos + len > inode->i_size) {
1170                ext4_truncate_failed_write(inode);
1171                /*
1172                 * If truncate failed early the inode might still be
1173                 * on the orphan list; we need to make sure the inode
1174                 * is removed from the orphan list in that case.
1175                 */
1176                if (inode->i_nlink)
1177                        ext4_orphan_del(NULL, inode);
1178        }
1179
1180        return ret ? ret : copied;
1181}
1182
1183/*
1184 * Reserve a single cluster located at lblock
1185 */
1186static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock)
1187{
1188        int retries = 0;
1189        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1190        struct ext4_inode_info *ei = EXT4_I(inode);
1191        unsigned int md_needed;
1192        int ret;
1193        ext4_lblk_t save_last_lblock;
1194        int save_len;
1195
1196        /*
1197         * We will charge metadata quota at writeout time; this saves
1198         * us from metadata over-estimation, though we may go over by
1199         * a small amount in the end.  Here we just reserve for data.
1200         */
1201        ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1));
1202        if (ret)
1203                return ret;
1204
1205        /*
1206         * recalculate the amount of metadata blocks to reserve
1207         * in order to allocate nrblocks
1208         * worse case is one extent per block
1209         */
1210repeat:
1211        spin_lock(&ei->i_block_reservation_lock);
1212        /*
1213         * ext4_calc_metadata_amount() has side effects, which we have
1214         * to be prepared undo if we fail to claim space.
1215         */
1216        save_len = ei->i_da_metadata_calc_len;
1217        save_last_lblock = ei->i_da_metadata_calc_last_lblock;
1218        md_needed = EXT4_NUM_B2C(sbi,
1219                                 ext4_calc_metadata_amount(inode, lblock));
1220        trace_ext4_da_reserve_space(inode, md_needed);
1221
1222        /*
1223         * We do still charge estimated metadata to the sb though;
1224         * we cannot afford to run out of free blocks.
1225         */
1226        if (ext4_claim_free_clusters(sbi, md_needed + 1, 0)) {
1227                ei->i_da_metadata_calc_len = save_len;
1228                ei->i_da_metadata_calc_last_lblock = save_last_lblock;
1229                spin_unlock(&ei->i_block_reservation_lock);
1230                if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
1231                        yield();
1232                        goto repeat;
1233                }
1234                dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
1235                return -ENOSPC;
1236        }
1237        ei->i_reserved_data_blocks++;
1238        ei->i_reserved_meta_blocks += md_needed;
1239        spin_unlock(&ei->i_block_reservation_lock);
1240
1241        return 0;       /* success */
1242}
1243
1244static void ext4_da_release_space(struct inode *inode, int to_free)
1245{
1246        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1247        struct ext4_inode_info *ei = EXT4_I(inode);
1248
1249        if (!to_free)
1250                return;         /* Nothing to release, exit */
1251
1252        spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1253
1254        trace_ext4_da_release_space(inode, to_free);
1255        if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1256                /*
1257                 * if there aren't enough reserved blocks, then the
1258                 * counter is messed up somewhere.  Since this
1259                 * function is called from invalidate page, it's
1260                 * harmless to return without any action.
1261                 */
1262                ext4_msg(inode->i_sb, KERN_NOTICE, "ext4_da_release_space: "
1263                         "ino %lu, to_free %d with only %d reserved "
1264                         "data blocks", inode->i_ino, to_free,
1265                         ei->i_reserved_data_blocks);
1266                WARN_ON(1);
1267                to_free = ei->i_reserved_data_blocks;
1268        }
1269        ei->i_reserved_data_blocks -= to_free;
1270
1271        if (ei->i_reserved_data_blocks == 0) {
1272                /*
1273                 * We can release all of the reserved metadata blocks
1274                 * only when we have written all of the delayed
1275                 * allocation blocks.
1276                 * Note that in case of bigalloc, i_reserved_meta_blocks,
1277                 * i_reserved_data_blocks, etc. refer to number of clusters.
1278                 */
1279                percpu_counter_sub(&sbi->s_dirtyclusters_counter,
1280                                   ei->i_reserved_meta_blocks);
1281                ei->i_reserved_meta_blocks = 0;
1282                ei->i_da_metadata_calc_len = 0;
1283        }
1284
1285        /* update fs dirty data blocks counter */
1286        percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
1287
1288        spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1289
1290        dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
1291}
1292
1293static void ext4_da_page_release_reservation(struct page *page,
1294                                             unsigned long offset)
1295{
1296        int to_release = 0;
1297        struct buffer_head *head, *bh;
1298        unsigned int curr_off = 0;
1299        struct inode *inode = page->mapping->host;
1300        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1301        int num_clusters;
1302
1303        head = page_buffers(page);
1304        bh = head;
1305        do {
1306                unsigned int next_off = curr_off + bh->b_size;
1307
1308                if ((offset <= curr_off) && (buffer_delay(bh))) {
1309                        to_release++;
1310                        clear_buffer_delay(bh);
1311                        clear_buffer_da_mapped(bh);
1312                }
1313                curr_off = next_off;
1314        } while ((bh = bh->b_this_page) != head);
1315
1316        /* If we have released all the blocks belonging to a cluster, then we
1317         * need to release the reserved space for that cluster. */
1318        num_clusters = EXT4_NUM_B2C(sbi, to_release);
1319        while (num_clusters > 0) {
1320                ext4_fsblk_t lblk;
1321                lblk = (page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits)) +
1322                        ((num_clusters - 1) << sbi->s_cluster_bits);
1323                if (sbi->s_cluster_ratio == 1 ||
1324                    !ext4_find_delalloc_cluster(inode, lblk, 1))
1325                        ext4_da_release_space(inode, 1);
1326
1327                num_clusters--;
1328        }
1329}
1330
1331/*
1332 * Delayed allocation stuff
1333 */
1334
1335/*
1336 * mpage_da_submit_io - walks through extent of pages and try to write
1337 * them with writepage() call back
1338 *
1339 * @mpd->inode: inode
1340 * @mpd->first_page: first page of the extent
1341 * @mpd->next_page: page after the last page of the extent
1342 *
1343 * By the time mpage_da_submit_io() is called we expect all blocks
1344 * to be allocated. this may be wrong if allocation failed.
1345 *
1346 * As pages are already locked by write_cache_pages(), we can't use it
1347 */
1348static int mpage_da_submit_io(struct mpage_da_data *mpd,
1349                              struct ext4_map_blocks *map)
1350{
1351        struct pagevec pvec;
1352        unsigned long index, end;
1353        int ret = 0, err, nr_pages, i;
1354        struct inode *inode = mpd->inode;
1355        struct address_space *mapping = inode->i_mapping;
1356        loff_t size = i_size_read(inode);
1357        unsigned int len, block_start;
1358        struct buffer_head *bh, *page_bufs = NULL;
1359        int journal_data = ext4_should_journal_data(inode);
1360        sector_t pblock = 0, cur_logical = 0;
1361        struct ext4_io_submit io_submit;
1362
1363        BUG_ON(mpd->next_page <= mpd->first_page);
1364        memset(&io_submit, 0, sizeof(io_submit));
1365        /*
1366         * We need to start from the first_page to the next_page - 1
1367         * to make sure we also write the mapped dirty buffer_heads.
1368         * If we look at mpd->b_blocknr we would only be looking
1369         * at the currently mapped buffer_heads.
1370         */
1371        index = mpd->first_page;
1372        end = mpd->next_page - 1;
1373
1374        pagevec_init(&pvec, 0);
1375        while (index <= end) {
1376                nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1377                if (nr_pages == 0)
1378                        break;
1379                for (i = 0; i < nr_pages; i++) {
1380                        int commit_write = 0, skip_page = 0;
1381                        struct page *page = pvec.pages[i];
1382
1383                        index = page->index;
1384                        if (index > end)
1385                                break;
1386
1387                        if (index == size >> PAGE_CACHE_SHIFT)
1388                                len = size & ~PAGE_CACHE_MASK;
1389                        else
1390                                len = PAGE_CACHE_SIZE;
1391                        if (map) {
1392                                cur_logical = index << (PAGE_CACHE_SHIFT -
1393                                                        inode->i_blkbits);
1394                                pblock = map->m_pblk + (cur_logical -
1395                                                        map->m_lblk);
1396                        }
1397                        index++;
1398
1399                        BUG_ON(!PageLocked(page));
1400                        BUG_ON(PageWriteback(page));
1401
1402                        /*
1403                         * If the page does not have buffers (for
1404                         * whatever reason), try to create them using
1405                         * __block_write_begin.  If this fails,
1406                         * skip the page and move on.
1407                         */
1408                        if (!page_has_buffers(page)) {
1409                                if (__block_write_begin(page, 0, len,
1410                                                noalloc_get_block_write)) {
1411                                skip_page:
1412                                        unlock_page(page);
1413                                        continue;
1414                                }
1415                                commit_write = 1;
1416                        }
1417
1418                        bh = page_bufs = page_buffers(page);
1419                        block_start = 0;
1420                        do {
1421                                if (!bh)
1422                                        goto skip_page;
1423                                if (map && (cur_logical >= map->m_lblk) &&
1424                                    (cur_logical <= (map->m_lblk +
1425                                                     (map->m_len - 1)))) {
1426                                        if (buffer_delay(bh)) {
1427                                                clear_buffer_delay(bh);
1428                                                bh->b_blocknr = pblock;
1429                                        }
1430                                        if (buffer_da_mapped(bh))
1431                                                clear_buffer_da_mapped(bh);
1432                                        if (buffer_unwritten(bh) ||
1433                                            buffer_mapped(bh))
1434                                                BUG_ON(bh->b_blocknr != pblock);
1435                                        if (map->m_flags & EXT4_MAP_UNINIT)
1436                                                set_buffer_uninit(bh);
1437                                        clear_buffer_unwritten(bh);
1438                                }
1439
1440                                /*
1441                                 * skip page if block allocation undone and
1442                                 * block is dirty
1443                                 */
1444                                if (ext4_bh_delay_or_unwritten(NULL, bh))
1445                                        skip_page = 1;
1446                                bh = bh->b_this_page;
1447                                block_start += bh->b_size;
1448                                cur_logical++;
1449                                pblock++;
1450                        } while (bh != page_bufs);
1451
1452                        if (skip_page)
1453                                goto skip_page;
1454
1455                        if (commit_write)
1456                                /* mark the buffer_heads as dirty & uptodate */
1457                                block_commit_write(page, 0, len);
1458
1459                        clear_page_dirty_for_io(page);
1460                        /*
1461                         * Delalloc doesn't support data journalling,
1462                         * but eventually maybe we'll lift this
1463                         * restriction.
1464                         */
1465                        if (unlikely(journal_data && PageChecked(page)))
1466                                err = __ext4_journalled_writepage(page, len);
1467                        else if (test_opt(inode->i_sb, MBLK_IO_SUBMIT))
1468                                err = ext4_bio_write_page(&io_submit, page,
1469                                                          len, mpd->wbc);
1470                        else if (buffer_uninit(page_bufs)) {
1471                                ext4_set_bh_endio(page_bufs, inode);
1472                                err = block_write_full_page_endio(page,
1473                                        noalloc_get_block_write,
1474                                        mpd->wbc, ext4_end_io_buffer_write);
1475                        } else
1476                                err = block_write_full_page(page,
1477                                        noalloc_get_block_write, mpd->wbc);
1478
1479                        if (!err)
1480                                mpd->pages_written++;
1481                        /*
1482                         * In error case, we have to continue because
1483                         * remaining pages are still locked
1484                         */
1485                        if (ret == 0)
1486                                ret = err;
1487                }
1488                pagevec_release(&pvec);
1489        }
1490        ext4_io_submit(&io_submit);
1491        return ret;
1492}
1493
1494static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd)
1495{
1496        int nr_pages, i;
1497        pgoff_t index, end;
1498        struct pagevec pvec;
1499        struct inode *inode = mpd->inode;
1500        struct address_space *mapping = inode->i_mapping;
1501
1502        index = mpd->first_page;
1503        end   = mpd->next_page - 1;
1504        while (index <= end) {
1505                nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1506                if (nr_pages == 0)
1507                        break;
1508                for (i = 0; i < nr_pages; i++) {
1509                        struct page *page = pvec.pages[i];
1510                        if (page->index > end)
1511                                break;
1512                        BUG_ON(!PageLocked(page));
1513                        BUG_ON(PageWriteback(page));
1514                        block_invalidatepage(page, 0);
1515                        ClearPageUptodate(page);
1516                        unlock_page(page);
1517                }
1518                index = pvec.pages[nr_pages - 1]->index + 1;
1519                pagevec_release(&pvec);
1520        }
1521        return;
1522}
1523
1524static void ext4_print_free_blocks(struct inode *inode)
1525{
1526        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1527        struct super_block *sb = inode->i_sb;
1528
1529        ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
1530               EXT4_C2B(EXT4_SB(inode->i_sb),
1531                        ext4_count_free_clusters(inode->i_sb)));
1532        ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
1533        ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
1534               (long long) EXT4_C2B(EXT4_SB(inode->i_sb),
1535                percpu_counter_sum(&sbi->s_freeclusters_counter)));
1536        ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
1537               (long long) EXT4_C2B(EXT4_SB(inode->i_sb),
1538                percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
1539        ext4_msg(sb, KERN_CRIT, "Block reservation details");
1540        ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
1541                 EXT4_I(inode)->i_reserved_data_blocks);
1542        ext4_msg(sb, KERN_CRIT, "i_reserved_meta_blocks=%u",
1543               EXT4_I(inode)->i_reserved_meta_blocks);
1544        return;
1545}
1546
1547/*
1548 * mpage_da_map_and_submit - go through given space, map them
1549 *       if necessary, and then submit them for I/O
1550 *
1551 * @mpd - bh describing space
1552 *
1553 * The function skips space we know is already mapped to disk blocks.
1554 *
1555 */
1556static void mpage_da_map_and_submit(struct mpage_da_data *mpd)
1557{
1558        int err, blks, get_blocks_flags;
1559        struct ext4_map_blocks map, *mapp = NULL;
1560        sector_t next = mpd->b_blocknr;
1561        unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits;
1562        loff_t disksize = EXT4_I(mpd->inode)->i_disksize;
1563        handle_t *handle = NULL;
1564
1565        /*
1566         * If the blocks are mapped already, or we couldn't accumulate
1567         * any blocks, then proceed immediately to the submission stage.
1568         */
1569        if ((mpd->b_size == 0) ||
1570            ((mpd->b_state  & (1 << BH_Mapped)) &&
1571             !(mpd->b_state & (1 << BH_Delay)) &&
1572             !(mpd->b_state & (1 << BH_Unwritten))))
1573                goto submit_io;
1574
1575        handle = ext4_journal_current_handle();
1576        BUG_ON(!handle);
1577
1578        /*
1579         * Call ext4_map_blocks() to allocate any delayed allocation
1580         * blocks, or to convert an uninitialized extent to be
1581         * initialized (in the case where we have written into
1582         * one or more preallocated blocks).
1583         *
1584         * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to
1585         * indicate that we are on the delayed allocation path.  This
1586         * affects functions in many different parts of the allocation
1587         * call path.  This flag exists primarily because we don't
1588         * want to change *many* call functions, so ext4_map_blocks()
1589         * will set the EXT4_STATE_DELALLOC_RESERVED flag once the
1590         * inode's allocation semaphore is taken.
1591         *
1592         * If the blocks in questions were delalloc blocks, set
1593         * EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting
1594         * variables are updated after the blocks have been allocated.
1595         */
1596        map.m_lblk = next;
1597        map.m_len = max_blocks;
1598        get_blocks_flags = EXT4_GET_BLOCKS_CREATE;
1599        if (ext4_should_dioread_nolock(mpd->inode))
1600                get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
1601        if (mpd->b_state & (1 << BH_Delay))
1602                get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
1603
1604        blks = ext4_map_blocks(handle, mpd->inode, &map, get_blocks_flags);
1605        if (blks < 0) {
1606                struct super_block *sb = mpd->inode->i_sb;
1607
1608                err = blks;
1609                /*
1610                 * If get block returns EAGAIN or ENOSPC and there
1611                 * appears to be free blocks we will just let
1612                 * mpage_da_submit_io() unlock all of the pages.
1613                 */
1614                if (err == -EAGAIN)
1615                        goto submit_io;
1616
1617                if (err == -ENOSPC && ext4_count_free_clusters(sb)) {
1618                        mpd->retval = err;
1619                        goto submit_io;
1620                }
1621
1622                /*
1623                 * get block failure will cause us to loop in
1624                 * writepages, because a_ops->writepage won't be able
1625                 * to make progress. The page will be redirtied by
1626                 * writepage and writepages will again try to write
1627                 * the same.
1628                 */
1629                if (!(EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)) {
1630                        ext4_msg(sb, KERN_CRIT,
1631                                 "delayed block allocation failed for inode %lu "
1632                                 "at logical offset %llu with max blocks %zd "
1633                                 "with error %d", mpd->inode->i_ino,
1634                                 (unsigned long long) next,
1635                                 mpd->b_size >> mpd->inode->i_blkbits, err);
1636                        ext4_msg(sb, KERN_CRIT,
1637                                "This should not happen!! Data will be lost\n");
1638                        if (err == -ENOSPC)
1639                                ext4_print_free_blocks(mpd->inode);
1640                }
1641                /* invalidate all the pages */
1642                ext4_da_block_invalidatepages(mpd);
1643
1644                /* Mark this page range as having been completed */
1645                mpd->io_done = 1;
1646                return;
1647        }
1648        BUG_ON(blks == 0);
1649
1650        mapp = &map;
1651        if (map.m_flags & EXT4_MAP_NEW) {
1652                struct block_device *bdev = mpd->inode->i_sb->s_bdev;
1653                int i;
1654
1655                for (i = 0; i < map.m_len; i++)
1656                        unmap_underlying_metadata(bdev, map.m_pblk + i);
1657
1658                if (ext4_should_order_data(mpd->inode)) {
1659                        err = ext4_jbd2_file_inode(handle, mpd->inode);
1660                        if (err) {
1661                                /* Only if the journal is aborted */
1662                                mpd->retval = err;
1663                                goto submit_io;
1664                        }
1665                }
1666        }
1667
1668        /*
1669         * Update on-disk size along with block allocation.
1670         */
1671        disksize = ((loff_t) next + blks) << mpd->inode->i_blkbits;
1672        if (disksize > i_size_read(mpd->inode))
1673                disksize = i_size_read(mpd->inode);
1674        if (disksize > EXT4_I(mpd->inode)->i_disksize) {
1675                ext4_update_i_disksize(mpd->inode, disksize);
1676                err = ext4_mark_inode_dirty(handle, mpd->inode);
1677                if (err)
1678                        ext4_error(mpd->inode->i_sb,
1679                                   "Failed to mark inode %lu dirty",
1680                                   mpd->inode->i_ino);
1681        }
1682
1683submit_io:
1684        mpage_da_submit_io(mpd, mapp);
1685        mpd->io_done = 1;
1686}
1687
1688#define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
1689                (1 << BH_Delay) | (1 << BH_Unwritten))
1690
1691/*
1692 * mpage_add_bh_to_extent - try to add one more block to extent of blocks
1693 *
1694 * @mpd->lbh - extent of blocks
1695 * @logical - logical number of the block in the file
1696 * @bh - bh of the block (used to access block's state)
1697 *
1698 * the function is used to collect contig. blocks in same state
1699 */
1700static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
1701                                   sector_t logical, size_t b_size,
1702                                   unsigned long b_state)
1703{
1704        sector_t next;
1705        int nrblocks = mpd->b_size >> mpd->inode->i_blkbits;
1706
1707        /*
1708         * XXX Don't go larger than mballoc is willing to allocate
1709         * This is a stopgap solution.  We eventually need to fold
1710         * mpage_da_submit_io() into this function and then call
1711         * ext4_map_blocks() multiple times in a loop
1712         */
1713        if (nrblocks >= 8*1024*1024/mpd->inode->i_sb->s_blocksize)
1714                goto flush_it;
1715
1716        /* check if thereserved journal credits might overflow */
1717        if (!(ext4_test_inode_flag(mpd->inode, EXT4_INODE_EXTENTS))) {
1718                if (nrblocks >= EXT4_MAX_TRANS_DATA) {
1719                        /*
1720                         * With non-extent format we are limited by the journal
1721                         * credit available.  Total credit needed to insert
1722                         * nrblocks contiguous blocks is dependent on the
1723                         * nrblocks.  So limit nrblocks.
1724                         */
1725                        goto flush_it;
1726                } else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) >
1727                                EXT4_MAX_TRANS_DATA) {
1728                        /*
1729                         * Adding the new buffer_head would make it cross the
1730                         * allowed limit for which we have journal credit
1731                         * reserved. So limit the new bh->b_size
1732                         */
1733                        b_size = (EXT4_MAX_TRANS_DATA - nrblocks) <<
1734                                                mpd->inode->i_blkbits;
1735                        /* we will do mpage_da_submit_io in the next loop */
1736                }
1737        }
1738        /*
1739         * First block in the extent
1740         */
1741        if (mpd->b_size == 0) {
1742                mpd->b_blocknr = logical;
1743                mpd->b_size = b_size;
1744                mpd->b_state = b_state & BH_FLAGS;
1745                return;
1746        }
1747
1748        next = mpd->b_blocknr + nrblocks;
1749        /*
1750         * Can we merge the block to our big extent?
1751         */
1752        if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) {
1753                mpd->b_size += b_size;
1754                return;
1755        }
1756
1757flush_it:
1758        /*
1759         * We couldn't merge the block to our extent, so we
1760         * need to flush current  extent and start new one
1761         */
1762        mpage_da_map_and_submit(mpd);
1763        return;
1764}
1765
1766static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
1767{
1768        return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
1769}
1770
1771/*
1772 * This function is grabs code from the very beginning of
1773 * ext4_map_blocks, but assumes that the caller is from delayed write
1774 * time. This function looks up the requested blocks and sets the
1775 * buffer delay bit under the protection of i_data_sem.
1776 */
1777static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
1778                              struct ext4_map_blocks *map,
1779                              struct buffer_head *bh)
1780{
1781        int retval;
1782        sector_t invalid_block = ~((sector_t) 0xffff);
1783
1784        if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
1785                invalid_block = ~0;
1786
1787        map->m_flags = 0;
1788        ext_debug("ext4_da_map_blocks(): inode %lu, max_blocks %u,"
1789                  "logical block %lu\n", inode->i_ino, map->m_len,
1790                  (unsigned long) map->m_lblk);
1791        /*
1792         * Try to see if we can get the block without requesting a new
1793         * file system block.
1794         */
1795        down_read((&EXT4_I(inode)->i_data_sem));
1796        if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
1797                retval = ext4_ext_map_blocks(NULL, inode, map, 0);
1798        else
1799                retval = ext4_ind_map_blocks(NULL, inode, map, 0);
1800
1801        if (retval == 0) {
1802                /*
1803                 * XXX: __block_prepare_write() unmaps passed block,
1804                 * is it OK?
1805                 */
1806                /* If the block was allocated from previously allocated cluster,
1807                 * then we dont need to reserve it again. */
1808                if (!(map->m_flags & EXT4_MAP_FROM_CLUSTER)) {
1809                        retval = ext4_da_reserve_space(inode, iblock);
1810                        if (retval)
1811                                /* not enough space to reserve */
1812                                goto out_unlock;
1813                }
1814
1815                /* Clear EXT4_MAP_FROM_CLUSTER flag since its purpose is served
1816                 * and it should not appear on the bh->b_state.
1817                 */
1818                map->m_flags &= ~EXT4_MAP_FROM_CLUSTER;
1819
1820                map_bh(bh, inode->i_sb, invalid_block);
1821                set_buffer_new(bh);
1822                set_buffer_delay(bh);
1823        }
1824
1825out_unlock:
1826        up_read((&EXT4_I(inode)->i_data_sem));
1827
1828        return retval;
1829}
1830
1831/*
1832 * This is a special get_blocks_t callback which is used by
1833 * ext4_da_write_begin().  It will either return mapped block or
1834 * reserve space for a single block.
1835 *
1836 * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
1837 * We also have b_blocknr = -1 and b_bdev initialized properly
1838 *
1839 * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
1840 * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
1841 * initialized properly.
1842 */
1843static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
1844                                  struct buffer_head *bh, int create)
1845{
1846        struct ext4_map_blocks map;
1847        int ret = 0;
1848
1849        BUG_ON(create == 0);
1850        BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
1851
1852        map.m_lblk = iblock;
1853        map.m_len = 1;
1854
1855        /*
1856         * first, we need to know whether the block is allocated already
1857         * preallocated blocks are unmapped but should treated
1858         * the same as allocated blocks.
1859         */
1860        ret = ext4_da_map_blocks(inode, iblock, &map, bh);
1861        if (ret <= 0)
1862                return ret;
1863
1864        map_bh(bh, inode->i_sb, map.m_pblk);
1865        bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
1866
1867        if (buffer_unwritten(bh)) {
1868                /* A delayed write to unwritten bh should be marked
1869                 * new and mapped.  Mapped ensures that we don't do
1870                 * get_block multiple times when we write to the same
1871                 * offset and new ensures that we do proper zero out
1872                 * for partial write.
1873                 */
1874                set_buffer_new(bh);
1875                set_buffer_mapped(bh);
1876        }
1877        return 0;
1878}
1879
1880/*
1881 * This function is used as a standard get_block_t calback function
1882 * when there is no desire to allocate any blocks.  It is used as a
1883 * callback function for block_write_begin() and block_write_full_page().
1884 * These functions should only try to map a single block at a time.
1885 *
1886 * Since this function doesn't do block allocations even if the caller
1887 * requests it by passing in create=1, it is critically important that
1888 * any caller checks to make sure that any buffer heads are returned
1889 * by this function are either all already mapped or marked for
1890 * delayed allocation before calling  block_write_full_page().  Otherwise,
1891 * b_blocknr could be left unitialized, and the page write functions will
1892 * be taken by surprise.
1893 */
1894static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
1895                                   struct buffer_head *bh_result, int create)
1896{
1897        BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
1898        return _ext4_get_block(inode, iblock, bh_result, 0);
1899}
1900
1901static int bget_one(handle_t *handle, struct buffer_head *bh)
1902{
1903        get_bh(bh);
1904        return 0;
1905}
1906
1907static int bput_one(handle_t *handle, struct buffer_head *bh)
1908{
1909        put_bh(bh);
1910        return 0;
1911}
1912
1913static int __ext4_journalled_writepage(struct page *page,
1914                                       unsigned int len)
1915{
1916        struct address_space *mapping = page->mapping;
1917        struct inode *inode = mapping->host;
1918        struct buffer_head *page_bufs;
1919        handle_t *handle = NULL;
1920        int ret = 0;
1921        int err;
1922
1923        ClearPageChecked(page);
1924        page_bufs = page_buffers(page);
1925        BUG_ON(!page_bufs);
1926        walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one);
1927        /* As soon as we unlock the page, it can go away, but we have
1928         * references to buffers so we are safe */
1929        unlock_page(page);
1930
1931        handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
1932        if (IS_ERR(handle)) {
1933                ret = PTR_ERR(handle);
1934                goto out;
1935        }
1936
1937        BUG_ON(!ext4_handle_valid(handle));
1938
1939        ret = walk_page_buffers(handle, page_bufs, 0, len, NULL,
1940                                do_journal_get_write_access);
1941
1942        err = walk_page_buffers(handle, page_bufs, 0, len, NULL,
1943                                write_end_fn);
1944        if (ret == 0)
1945                ret = err;
1946        EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1947        err = ext4_journal_stop(handle);
1948        if (!ret)
1949                ret = err;
1950
1951        walk_page_buffers(handle, page_bufs, 0, len, NULL, bput_one);
1952        ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1953out:
1954        return ret;
1955}
1956
1957static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode);
1958static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate);
1959
1960/*
1961 * Note that we don't need to start a transaction unless we're journaling data
1962 * because we should have holes filled from ext4_page_mkwrite(). We even don't
1963 * need to file the inode to the transaction's list in ordered mode because if
1964 * we are writing back data added by write(), the inode is already there and if
1965 * we are writing back data modified via mmap(), no one guarantees in which
1966 * transaction the data will hit the disk. In case we are journaling data, we
1967 * cannot start transaction directly because transaction start ranks above page
1968 * lock so we have to do some magic.
1969 *
1970 * This function can get called via...
1971 *   - ext4_da_writepages after taking page lock (have journal handle)
1972 *   - journal_submit_inode_data_buffers (no journal handle)
1973 *   - shrink_page_list via the kswapd/direct reclaim (no journal handle)
1974 *   - grab_page_cache when doing write_begin (have journal handle)
1975 *
1976 * We don't do any block allocation in this function. If we have page with
1977 * multiple blocks we need to write those buffer_heads that are mapped. This
1978 * is important for mmaped based write. So if we do with blocksize 1K
1979 * truncate(f, 1024);
1980 * a = mmap(f, 0, 4096);
1981 * a[0] = 'a';
1982 * truncate(f, 4096);
1983 * we have in the page first buffer_head mapped via page_mkwrite call back
1984 * but other buffer_heads would be unmapped but dirty (dirty done via the
1985 * do_wp_page). So writepage should write the first block. If we modify
1986 * the mmap area beyond 1024 we will again get a page_fault and the
1987 * page_mkwrite callback will do the block allocation and mark the
1988 * buffer_heads mapped.
1989 *
1990 * We redirty the page if we have any buffer_heads that is either delay or
1991 * unwritten in the page.
1992 *
1993 * We can get recursively called as show below.
1994 *
1995 *      ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1996 *              ext4_writepage()
1997 *
1998 * But since we don't do any block allocation we should not deadlock.
1999 * Page also have the dirty flag cleared so we don't get recurive page_lock.
2000 */
2001static int ext4_writepage(struct page *page,
2002                          struct writeback_control *wbc)
2003{
2004        int ret = 0, commit_write = 0;
2005        loff_t size;
2006        unsigned int len;
2007        struct buffer_head *page_bufs = NULL;
2008        struct inode *inode = page->mapping->host;
2009
2010        trace_ext4_writepage(page);
2011        size = i_size_read(inode);
2012        if (page->index == size >> PAGE_CACHE_SHIFT)
2013                len = size & ~PAGE_CACHE_MASK;
2014        else
2015                len = PAGE_CACHE_SIZE;
2016
2017        /*
2018         * If the page does not have buffers (for whatever reason),
2019         * try to create them using __block_write_begin.  If this
2020         * fails, redirty the page and move on.
2021         */
2022        if (!page_has_buffers(page)) {
2023                if (__block_write_begin(page, 0, len,
2024                                        noalloc_get_block_write)) {
2025                redirty_page:
2026                        redirty_page_for_writepage(wbc, page);
2027                        unlock_page(page);
2028                        return 0;
2029                }
2030                commit_write = 1;
2031        }
2032        page_bufs = page_buffers(page);
2033        if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2034                              ext4_bh_delay_or_unwritten)) {
2035                /*
2036                 * We don't want to do block allocation, so redirty
2037                 * the page and return.  We may reach here when we do
2038                 * a journal commit via journal_submit_inode_data_buffers.
2039                 * We can also reach here via shrink_page_list but it
2040                 * should never be for direct reclaim so warn if that
2041                 * happens
2042                 */
2043                WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) ==
2044                                                                PF_MEMALLOC);
2045                goto redirty_page;
2046        }
2047        if (commit_write)
2048                /* now mark the buffer_heads as dirty and uptodate */
2049                block_commit_write(page, 0, len);
2050
2051        if (PageChecked(page) && ext4_should_journal_data(inode))
2052                /*
2053                 * It's mmapped pagecache.  Add buffers and journal it.  There
2054                 * doesn't seem much point in redirtying the page here.
2055                 */
2056                return __ext4_journalled_writepage(page, len);
2057
2058        if (buffer_uninit(page_bufs)) {
2059                ext4_set_bh_endio(page_bufs, inode);
2060                ret = block_write_full_page_endio(page, noalloc_get_block_write,
2061                                            wbc, ext4_end_io_buffer_write);
2062        } else
2063                ret = block_write_full_page(page, noalloc_get_block_write,
2064                                            wbc);
2065
2066        return ret;
2067}
2068
2069/*
2070 * This is called via ext4_da_writepages() to
2071 * calculate the total number of credits to reserve to fit
2072 * a single extent allocation into a single transaction,
2073 * ext4_da_writpeages() will loop calling this before
2074 * the block allocation.
2075 */
2076
2077static int ext4_da_writepages_trans_blocks(struct inode *inode)
2078{
2079        int max_blocks = EXT4_I(inode)->i_reserved_data_blocks;
2080
2081        /*
2082         * With non-extent format the journal credit needed to
2083         * insert nrblocks contiguous block is dependent on
2084         * number of contiguous block. So we will limit
2085         * number of contiguous block to a sane value
2086         */
2087        if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) &&
2088            (max_blocks > EXT4_MAX_TRANS_DATA))
2089                max_blocks = EXT4_MAX_TRANS_DATA;
2090
2091        return ext4_chunk_trans_blocks(inode, max_blocks);
2092}
2093
2094/*
2095 * write_cache_pages_da - walk the list of dirty pages of the given
2096 * address space and accumulate pages that need writing, and call
2097 * mpage_da_map_and_submit to map a single contiguous memory region
2098 * and then write them.
2099 */
2100static int write_cache_pages_da(struct address_space *mapping,
2101                                struct writeback_control *wbc,
2102                                struct mpage_da_data *mpd,
2103                                pgoff_t *done_index)
2104{
2105        struct buffer_head      *bh, *head;
2106        struct inode            *inode = mapping->host;
2107        struct pagevec          pvec;
2108        unsigned int            nr_pages;
2109        sector_t                logical;
2110        pgoff_t                 index, end;
2111        long                    nr_to_write = wbc->nr_to_write;
2112        int                     i, tag, ret = 0;
2113
2114        memset(mpd, 0, sizeof(struct mpage_da_data));
2115        mpd->wbc = wbc;
2116        mpd->inode = inode;
2117        pagevec_init(&pvec, 0);
2118        index = wbc->range_start >> PAGE_CACHE_SHIFT;
2119        end = wbc->range_end >> PAGE_CACHE_SHIFT;
2120
2121        if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2122                tag = PAGECACHE_TAG_TOWRITE;
2123        else
2124                tag = PAGECACHE_TAG_DIRTY;
2125
2126        *done_index = index;
2127        while (index <= end) {
2128                nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
2129                              min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
2130                if (nr_pages == 0)
2131                        return 0;
2132
2133                for (i = 0; i < nr_pages; i++) {
2134                        struct page *page = pvec.pages[i];
2135
2136                        /*
2137                         * At this point, the page may be truncated or
2138                         * invalidated (changing page->mapping to NULL), or
2139                         * even swizzled back from swapper_space to tmpfs file
2140                         * mapping. However, page->index will not change
2141                         * because we have a reference on the page.
2142                         */
2143                        if (page->index > end)
2144                                goto out;
2145
2146                        *done_index = page->index + 1;
2147
2148                        /*
2149                         * If we can't merge this page, and we have
2150                         * accumulated an contiguous region, write it
2151                         */
2152                        if ((mpd->next_page != page->index) &&
2153                            (mpd->next_page != mpd->first_page)) {
2154                                mpage_da_map_and_submit(mpd);
2155                                goto ret_extent_tail;
2156                        }
2157
2158                        lock_page(page);
2159
2160                        /*
2161                         * If the page is no longer dirty, or its
2162                         * mapping no longer corresponds to inode we
2163                         * are writing (which means it has been
2164                         * truncated or invalidated), or the page is
2165                         * already under writeback and we are not
2166                         * doing a data integrity writeback, skip the page
2167                         */
2168                        if (!PageDirty(page) ||
2169                            (PageWriteback(page) &&
2170                             (wbc->sync_mode == WB_SYNC_NONE)) ||
2171                            unlikely(page->mapping != mapping)) {
2172                                unlock_page(page);
2173                                continue;
2174                        }
2175
2176                        wait_on_page_writeback(page);
2177                        BUG_ON(PageWriteback(page));
2178
2179                        if (mpd->next_page != page->index)
2180                                mpd->first_page = page->index;
2181                        mpd->next_page = page->index + 1;
2182                        logical = (sector_t) page->index <<
2183                                (PAGE_CACHE_SHIFT - inode->i_blkbits);
2184
2185                        if (!page_has_buffers(page)) {
2186                                mpage_add_bh_to_extent(mpd, logical,
2187                                                       PAGE_CACHE_SIZE,
2188                                                       (1 << BH_Dirty) | (1 << BH_Uptodate));
2189                                if (mpd->io_done)
2190                                        goto ret_extent_tail;
2191                        } else {
2192                                /*
2193                                 * Page with regular buffer heads,
2194                                 * just add all dirty ones
2195                                 */
2196                                head = page_buffers(page);
2197                                bh = head;
2198                                do {
2199                                        BUG_ON(buffer_locked(bh));
2200                                        /*
2201                                         * We need to try to allocate
2202                                         * unmapped blocks in the same page.
2203                                         * Otherwise we won't make progress
2204                                         * with the page in ext4_writepage
2205                                         */
2206                                        if (ext4_bh_delay_or_unwritten(NULL, bh)) {
2207                                                mpage_add_bh_to_extent(mpd, logical,
2208                                                                       bh->b_size,
2209                                                                       bh->b_state);
2210                                                if (mpd->io_done)
2211                                                        goto ret_extent_tail;
2212                                        } else if (buffer_dirty(bh) && (buffer_mapped(bh))) {
2213                                                /*
2214                                                 * mapped dirty buffer. We need
2215                                                 * to update the b_state
2216                                                 * because we look at b_state
2217                                                 * in mpage_da_map_blocks.  We
2218                                                 * don't update b_size because
2219                                                 * if we find an unmapped
2220                                                 * buffer_head later we need to
2221                                                 * use the b_state flag of that
2222                                                 * buffer_head.
2223                                                 */
2224                                                if (mpd->b_size == 0)
2225                                                        mpd->b_state = bh->b_state & BH_FLAGS;
2226                                        }
2227                                        logical++;
2228                                } while ((bh = bh->b_this_page) != head);
2229                        }
2230
2231                        if (nr_to_write > 0) {
2232                                nr_to_write--;
2233                                if (nr_to_write == 0 &&
2234                                    wbc->sync_mode == WB_SYNC_NONE)
2235                                        /*
2236                                         * We stop writing back only if we are
2237                                         * not doing integrity sync. In case of
2238                                         * integrity sync we have to keep going
2239                                         * because someone may be concurrently
2240                                         * dirtying pages, and we might have
2241                                         * synced a lot of newly appeared dirty
2242                                         * pages, but have not synced all of the
2243                                         * old dirty pages.
2244                                         */
2245                                        goto out;
2246                        }
2247                }
2248                pagevec_release(&pvec);
2249                cond_resched();
2250        }
2251        return 0;
2252ret_extent_tail:
2253        ret = MPAGE_DA_EXTENT_TAIL;
2254out:
2255        pagevec_release(&pvec);
2256        cond_resched();
2257        return ret;
2258}
2259
2260
2261static int ext4_da_writepages(struct address_space *mapping,
2262                              struct writeback_control *wbc)
2263{
2264        pgoff_t index;
2265        int range_whole = 0;
2266        handle_t *handle = NULL;
2267        struct mpage_da_data mpd;
2268        struct inode *inode = mapping->host;
2269        int pages_written = 0;
2270        unsigned int max_pages;
2271        int range_cyclic, cycled = 1, io_done = 0;
2272        int needed_blocks, ret = 0;
2273        long desired_nr_to_write, nr_to_writebump = 0;
2274        loff_t range_start = wbc->range_start;
2275        struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2276        pgoff_t done_index = 0;
2277        pgoff_t end;
2278        struct blk_plug plug;
2279
2280        trace_ext4_da_writepages(inode, wbc);
2281
2282        /*
2283         * No pages to write? This is mainly a kludge to avoid starting
2284         * a transaction for special inodes like journal inode on last iput()
2285         * because that could violate lock ordering on umount
2286         */
2287        if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2288                return 0;
2289
2290        /*
2291         * If the filesystem has aborted, it is read-only, so return
2292         * right away instead of dumping stack traces later on that
2293         * will obscure the real source of the problem.  We test
2294         * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because
2295         * the latter could be true if the filesystem is mounted
2296         * read-only, and in that case, ext4_da_writepages should
2297         * *never* be called, so if that ever happens, we would want
2298         * the stack trace.
2299         */
2300        if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED))
2301                return -EROFS;
2302
2303        if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2304                range_whole = 1;
2305
2306        range_cyclic = wbc->range_cyclic;
2307        if (wbc->range_cyclic) {
2308                index = mapping->writeback_index;
2309                if (index)
2310                        cycled = 0;
2311                wbc->range_start = index << PAGE_CACHE_SHIFT;
2312                wbc->range_end  = LLONG_MAX;
2313                wbc->range_cyclic = 0;
2314                end = -1;
2315        } else {
2316                index = wbc->range_start >> PAGE_CACHE_SHIFT;
2317                end = wbc->range_end >> PAGE_CACHE_SHIFT;
2318        }
2319
2320        /*
2321         * This works around two forms of stupidity.  The first is in
2322         * the writeback code, which caps the maximum number of pages
2323         * written to be 1024 pages.  This is wrong on multiple
2324         * levels; different architectues have a different page size,
2325         * which changes the maximum amount of data which gets
2326         * written.  Secondly, 4 megabytes is way too small.  XFS
2327         * forces this value to be 16 megabytes by multiplying
2328         * nr_to_write parameter by four, and then relies on its
2329         * allocator to allocate larger extents to make them
2330         * contiguous.  Unfortunately this brings us to the second
2331         * stupidity, which is that ext4's mballoc code only allocates
2332         * at most 2048 blocks.  So we force contiguous writes up to
2333         * the number of dirty blocks in the inode, or
2334         * sbi->max_writeback_mb_bump whichever is smaller.
2335         */
2336        max_pages = sbi->s_max_writeback_mb_bump << (20 - PAGE_CACHE_SHIFT);
2337        if (!range_cyclic && range_whole) {
2338                if (wbc->nr_to_write == LONG_MAX)
2339                        desired_nr_to_write = wbc->nr_to_write;
2340                else
2341                        desired_nr_to_write = wbc->nr_to_write * 8;
2342        } else
2343                desired_nr_to_write = ext4_num_dirty_pages(inode, index,
2344                                                           max_pages);
2345        if (desired_nr_to_write > max_pages)
2346                desired_nr_to_write = max_pages;
2347
2348        if (wbc->nr_to_write < desired_nr_to_write) {
2349                nr_to_writebump = desired_nr_to_write - wbc->nr_to_write;
2350                wbc->nr_to_write = desired_nr_to_write;
2351        }
2352
2353retry:
2354        if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2355                tag_pages_for_writeback(mapping, index, end);
2356
2357        blk_start_plug(&plug);
2358        while (!ret && wbc->nr_to_write > 0) {
2359
2360                /*
2361                 * we  insert one extent at a time. So we need
2362                 * credit needed for single extent allocation.
2363                 * journalled mode is currently not supported
2364                 * by delalloc
2365                 */
2366                BUG_ON(ext4_should_journal_data(inode));
2367                needed_blocks = ext4_da_writepages_trans_blocks(inode);
2368
2369                /* start a new transaction*/
2370                handle = ext4_journal_start(inode, needed_blocks);
2371                if (IS_ERR(handle)) {
2372                        ret = PTR_ERR(handle);
2373                        ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2374                               "%ld pages, ino %lu; err %d", __func__,
2375                                wbc->nr_to_write, inode->i_ino, ret);
2376                        blk_finish_plug(&plug);
2377                        goto out_writepages;
2378                }
2379
2380                /*
2381                 * Now call write_cache_pages_da() to find the next
2382                 * contiguous region of logical blocks that need
2383                 * blocks to be allocated by ext4 and submit them.
2384                 */
2385                ret = write_cache_pages_da(mapping, wbc, &mpd, &done_index);
2386                /*
2387                 * If we have a contiguous extent of pages and we
2388                 * haven't done the I/O yet, map the blocks and submit
2389                 * them for I/O.
2390                 */
2391                if (!mpd.io_done && mpd.next_page != mpd.first_page) {
2392                        mpage_da_map_and_submit(&mpd);
2393                        ret = MPAGE_DA_EXTENT_TAIL;
2394                }
2395                trace_ext4_da_write_pages(inode, &mpd);
2396                wbc->nr_to_write -= mpd.pages_written;
2397
2398                ext4_journal_stop(handle);
2399
2400                if ((mpd.retval == -ENOSPC) && sbi->s_journal) {
2401                        /* commit the transaction which would
2402                         * free blocks released in the transaction
2403                         * and try again
2404                         */
2405                        jbd2_journal_force_commit_nested(sbi->s_journal);
2406                        ret = 0;
2407                } else if (ret == MPAGE_DA_EXTENT_TAIL) {
2408                        /*
2409                         * Got one extent now try with rest of the pages.
2410                         * If mpd.retval is set -EIO, journal is aborted.
2411                         * So we don't need to write any more.
2412                         */
2413                        pages_written += mpd.pages_written;
2414                        ret = mpd.retval;
2415                        io_done = 1;
2416                } else if (wbc->nr_to_write)
2417                        /*
2418                         * There is no more writeout needed
2419                         * or we requested for a noblocking writeout
2420                         * and we found the device congested
2421                         */
2422                        break;
2423        }
2424        blk_finish_plug(&plug);
2425        if (!io_done && !cycled) {
2426                cycled = 1;
2427                index = 0;
2428                wbc->range_start = index << PAGE_CACHE_SHIFT;
2429                wbc->range_end  = mapping->writeback_index - 1;
2430                goto retry;
2431        }
2432
2433        /* Update index */
2434        wbc->range_cyclic = range_cyclic;
2435        if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2436                /*
2437                 * set the writeback_index so that range_cyclic
2438                 * mode will write it back later
2439                 */
2440                mapping->writeback_index = done_index;
2441
2442out_writepages:
2443        wbc->nr_to_write -= nr_to_writebump;
2444        wbc->range_start = range_start;
2445        trace_ext4_da_writepages_result(inode, wbc, ret, pages_written);
2446        return ret;
2447}
2448
2449#define FALL_BACK_TO_NONDELALLOC 1
2450static int ext4_nonda_switch(struct super_block *sb)
2451{
2452        s64 free_blocks, dirty_blocks;
2453        struct ext4_sb_info *sbi = EXT4_SB(sb);
2454
2455        /*
2456         * switch to non delalloc mode if we are running low
2457         * on free block. The free block accounting via percpu
2458         * counters can get slightly wrong with percpu_counter_batch getting
2459         * accumulated on each CPU without updating global counters
2460         * Delalloc need an accurate free block accounting. So switch
2461         * to non delalloc when we are near to error range.
2462         */
2463        free_blocks  = EXT4_C2B(sbi,
2464                percpu_counter_read_positive(&sbi->s_freeclusters_counter));
2465        dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
2466        if (2 * free_blocks < 3 * dirty_blocks ||
2467                free_blocks < (dirty_blocks + EXT4_FREECLUSTERS_WATERMARK)) {
2468                /*
2469                 * free block count is less than 150% of dirty blocks
2470                 * or free blocks is less than watermark
2471                 */
2472                return 1;
2473        }
2474        /*
2475         * Even if we don't switch but are nearing capacity,
2476         * start pushing delalloc when 1/2 of free blocks are dirty.
2477         */
2478        if (free_blocks < 2 * dirty_blocks)
2479                writeback_inodes_sb_if_idle(sb, WB_REASON_FS_FREE_SPACE);
2480
2481        return 0;
2482}
2483
2484static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2485                               loff_t pos, unsigned len, unsigned flags,
2486                               struct page **pagep, void **fsdata)
2487{
2488        int ret, retries = 0;
2489        struct page *page;
2490        pgoff_t index;
2491        struct inode *inode = mapping->host;
2492        handle_t *handle;
2493
2494        index = pos >> PAGE_CACHE_SHIFT;
2495
2496        if (ext4_nonda_switch(inode->i_sb)) {
2497                *fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
2498                return ext4_write_begin(file, mapping, pos,
2499                                        len, flags, pagep, fsdata);
2500        }
2501        *fsdata = (void *)0;
2502        trace_ext4_da_write_begin(inode, pos, len, flags);
2503retry:
2504        /*
2505         * With delayed allocation, we don't log the i_disksize update
2506         * if there is delayed block allocation. But we still need
2507         * to journalling the i_disksize update if writes to the end
2508         * of file which has an already mapped buffer.
2509         */
2510        handle = ext4_journal_start(inode, 1);
2511        if (IS_ERR(handle)) {
2512                ret = PTR_ERR(handle);
2513                goto out;
2514        }
2515        /* We cannot recurse into the filesystem as the transaction is already
2516         * started */
2517        flags |= AOP_FLAG_NOFS;
2518
2519        page = grab_cache_page_write_begin(mapping, index, flags);
2520        if (!page) {
2521                ext4_journal_stop(handle);
2522                ret = -ENOMEM;
2523                goto out;
2524        }
2525        *pagep = page;
2526
2527        ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
2528        if (ret < 0) {
2529                unlock_page(page);
2530                ext4_journal_stop(handle);
2531                page_cache_release(page);
2532                /*
2533                 * block_write_begin may have instantiated a few blocks
2534                 * outside i_size.  Trim these off again. Don't need
2535                 * i_size_read because we hold i_mutex.
2536                 */
2537                if (pos + len > inode->i_size)
2538                        ext4_truncate_failed_write(inode);
2539        }
2540
2541        if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
2542                goto retry;
2543out:
2544        return ret;
2545}
2546
2547/*
2548 * Check if we should update i_disksize
2549 * when write to the end of file but not require block allocation
2550 */
2551static int ext4_da_should_update_i_disksize(struct page *page,
2552                                            unsigned long offset)
2553{
2554        struct buffer_head *bh;
2555        struct inode *inode = page->mapping->host;
2556        unsigned int idx;
2557        int i;
2558
2559        bh = page_buffers(page);
2560        idx = offset >> inode->i_blkbits;
2561
2562        for (i = 0; i < idx; i++)
2563                bh = bh->b_this_page;
2564
2565        if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
2566                return 0;
2567        return 1;
2568}
2569
2570static int ext4_da_write_end(struct file *file,
2571                             struct address_space *mapping,
2572                             loff_t pos, unsigned len, unsigned copied,
2573                             struct page *page, void *fsdata)
2574{
2575        struct inode *inode = mapping->host;
2576        int ret = 0, ret2;
2577        handle_t *handle = ext4_journal_current_handle();
2578        loff_t new_i_size;
2579        unsigned long start, end;
2580        int write_mode = (int)(unsigned long)fsdata;
2581
2582        if (write_mode == FALL_BACK_TO_NONDELALLOC) {
2583                switch (ext4_inode_journal_mode(inode)) {
2584                case EXT4_INODE_ORDERED_DATA_MODE:
2585                        return ext4_ordered_write_end(file, mapping, pos,
2586                                        len, copied, page, fsdata);
2587                case EXT4_INODE_WRITEBACK_DATA_MODE:
2588                        return ext4_writeback_write_end(file, mapping, pos,
2589                                        len, copied, page, fsdata);
2590                default:
2591                        BUG();
2592                }
2593        }
2594
2595        trace_ext4_da_write_end(inode, pos, len, copied);
2596        start = pos & (PAGE_CACHE_SIZE - 1);
2597        end = start + copied - 1;
2598
2599        /*
2600         * generic_write_end() will run mark_inode_dirty() if i_size
2601         * changes.  So let's piggyback the i_disksize mark_inode_dirty
2602         * into that.
2603         */
2604
2605        new_i_size = pos + copied;
2606        if (copied && new_i_size > EXT4_I(inode)->i_disksize) {
2607                if (ext4_da_should_update_i_disksize(page, end)) {
2608                        down_write(&EXT4_I(inode)->i_data_sem);
2609                        if (new_i_size > EXT4_I(inode)->i_disksize) {
2610                                /*
2611                                 * Updating i_disksize when extending file
2612                                 * without needing block allocation
2613                                 */
2614                                if (ext4_should_order_data(inode))
2615                                        ret = ext4_jbd2_file_inode(handle,
2616                                                                   inode);
2617
2618                                EXT4_I(inode)->i_disksize = new_i_size;
2619                        }
2620                        up_write(&EXT4_I(inode)->i_data_sem);
2621                        /* We need to mark inode dirty even if
2622                         * new_i_size is less that inode->i_size
2623                         * bu greater than i_disksize.(hint delalloc)
2624                         */
2625                        ext4_mark_inode_dirty(handle, inode);
2626                }
2627        }
2628        ret2 = generic_write_end(file, mapping, pos, len, copied,
2629                                                        page, fsdata);
2630        copied = ret2;
2631        if (ret2 < 0)
2632                ret = ret2;
2633        ret2 = ext4_journal_stop(handle);
2634        if (!ret)
2635                ret = ret2;
2636
2637        return ret ? ret : copied;
2638}
2639
2640static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
2641{
2642        /*
2643         * Drop reserved blocks
2644         */
2645        BUG_ON(!PageLocked(page));
2646        if (!page_has_buffers(page))
2647                goto out;
2648
2649        ext4_da_page_release_reservation(page, offset);
2650
2651out:
2652        ext4_invalidatepage(page, offset);
2653
2654        return;
2655}
2656
2657/*
2658 * Force all delayed allocation blocks to be allocated for a given inode.
2659 */
2660int ext4_alloc_da_blocks(struct inode *inode)
2661{
2662        trace_ext4_alloc_da_blocks(inode);
2663
2664        if (!EXT4_I(inode)->i_reserved_data_blocks &&
2665            !EXT4_I(inode)->i_reserved_meta_blocks)
2666                return 0;
2667
2668        /*
2669         * We do something simple for now.  The filemap_flush() will
2670         * also start triggering a write of the data blocks, which is
2671         * not strictly speaking necessary (and for users of
2672         * laptop_mode, not even desirable).  However, to do otherwise
2673         * would require replicating code paths in:
2674         *
2675         * ext4_da_writepages() ->
2676         *    write_cache_pages() ---> (via passed in callback function)
2677         *        __mpage_da_writepage() -->
2678         *           mpage_add_bh_to_extent()
2679         *           mpage_da_map_blocks()
2680         *
2681         * The problem is that write_cache_pages(), located in
2682         * mm/page-writeback.c, marks pages clean in preparation for
2683         * doing I/O, which is not desirable if we're not planning on
2684         * doing I/O at all.
2685         *
2686         * We could call write_cache_pages(), and then redirty all of
2687         * the pages by calling redirty_page_for_writepage() but that
2688         * would be ugly in the extreme.  So instead we would need to
2689         * replicate parts of the code in the above functions,
2690         * simplifying them because we wouldn't actually intend to
2691         * write out the pages, but rather only collect contiguous
2692         * logical block extents, call the multi-block allocator, and
2693         * then update the buffer heads with the block allocations.
2694         *
2695         * For now, though, we'll cheat by calling filemap_flush(),
2696         * which will map the blocks, and start the I/O, but not
2697         * actually wait for the I/O to complete.
2698         */
2699        return filemap_flush(inode->i_mapping);
2700}
2701
2702/*
2703 * bmap() is special.  It gets used by applications such as lilo and by
2704 * the swapper to find the on-disk block of a specific piece of data.
2705 *
2706 * Naturally, this is dangerous if the block concerned is still in the
2707 * journal.  If somebody makes a swapfile on an ext4 data-journaling
2708 * filesystem and enables swap, then they may get a nasty shock when the
2709 * data getting swapped to that swapfile suddenly gets overwritten by
2710 * the original zero's written out previously to the journal and
2711 * awaiting writeback in the kernel's buffer cache.
2712 *
2713 * So, if we see any bmap calls here on a modified, data-journaled file,
2714 * take extra steps to flush any blocks which might be in the cache.
2715 */
2716static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
2717{
2718        struct inode *inode = mapping->host;
2719        journal_t *journal;
2720        int err;
2721
2722        if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
2723                        test_opt(inode->i_sb, DELALLOC)) {
2724                /*
2725                 * With delalloc we want to sync the file
2726                 * so that we can make sure we allocate
2727                 * blocks for file
2728                 */
2729                filemap_write_and_wait(mapping);
2730        }
2731
2732        if (EXT4_JOURNAL(inode) &&
2733            ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
2734                /*
2735                 * This is a REALLY heavyweight approach, but the use of
2736                 * bmap on dirty files is expected to be extremely rare:
2737                 * only if we run lilo or swapon on a freshly made file
2738                 * do we expect this to happen.
2739                 *
2740                 * (bmap requires CAP_SYS_RAWIO so this does not
2741                 * represent an unprivileged user DOS attack --- we'd be
2742                 * in trouble if mortal users could trigger this path at
2743                 * will.)
2744                 *
2745                 * NB. EXT4_STATE_JDATA is not set on files other than
2746                 * regular files.  If somebody wants to bmap a directory
2747                 * or symlink and gets confused because the buffer
2748                 * hasn't yet been flushed to disk, they deserve
2749                 * everything they get.
2750                 */
2751
2752                ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
2753                journal = EXT4_JOURNAL(inode);
2754                jbd2_journal_lock_updates(journal);
2755                err = jbd2_journal_flush(journal);
2756                jbd2_journal_unlock_updates(journal);
2757
2758                if (err)
2759                        return 0;
2760        }
2761
2762        return generic_block_bmap(mapping, block, ext4_get_block);
2763}
2764
2765static int ext4_readpage(struct file *file, struct page *page)
2766{
2767        trace_ext4_readpage(page);
2768        return mpage_readpage(page, ext4_get_block);
2769}
2770
2771static int
2772ext4_readpages(struct file *file, struct address_space *mapping,
2773                struct list_head *pages, unsigned nr_pages)
2774{
2775        return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
2776}
2777
2778static void ext4_invalidatepage_free_endio(struct page *page, unsigned long offset)
2779{
2780        struct buffer_head *head, *bh;
2781        unsigned int curr_off = 0;
2782
2783        if (!page_has_buffers(page))
2784                return;
2785        head = bh = page_buffers(page);
2786        do {
2787                if (offset <= curr_off && test_clear_buffer_uninit(bh)
2788                                        && bh->b_private) {
2789                        ext4_free_io_end(bh->b_private);
2790                        bh->b_private = NULL;
2791                        bh->b_end_io = NULL;
2792                }
2793                curr_off = curr_off + bh->b_size;
2794                bh = bh->b_this_page;
2795        } while (bh != head);
2796}
2797
2798static void ext4_invalidatepage(struct page *page, unsigned long offset)
2799{
2800        journal_t *journal = EXT4_JOURNAL(page->mapping->host);
2801
2802        trace_ext4_invalidatepage(page, offset);
2803
2804        /*
2805         * free any io_end structure allocated for buffers to be discarded
2806         */
2807        if (ext4_should_dioread_nolock(page->mapping->host))
2808                ext4_invalidatepage_free_endio(page, offset);
2809        /*
2810         * If it's a full truncate we just forget about the pending dirtying
2811         */
2812        if (offset == 0)
2813                ClearPageChecked(page);
2814
2815        if (journal)
2816                jbd2_journal_invalidatepage(journal, page, offset);
2817        else
2818                block_invalidatepage(page, offset);
2819}
2820
2821static int ext4_releasepage(struct page *page, gfp_t wait)
2822{
2823        journal_t *journal = EXT4_JOURNAL(page->mapping->host);
2824
2825        trace_ext4_releasepage(page);
2826
2827        WARN_ON(PageChecked(page));
2828        if (!page_has_buffers(page))
2829                return 0;
2830        if (journal)
2831                return jbd2_journal_try_to_free_buffers(journal, page, wait);
2832        else
2833                return try_to_free_buffers(page);
2834}
2835
2836/*
2837 * ext4_get_block used when preparing for a DIO write or buffer write.
2838 * We allocate an uinitialized extent if blocks haven't been allocated.
2839 * The extent will be converted to initialized after the IO is complete.
2840 */
2841static int ext4_get_block_write(struct inode *inode, sector_t iblock,
2842                   struct buffer_head *bh_result, int create)
2843{
2844        ext4_debug("ext4_get_block_write: inode %lu, create flag %d\n",
2845                   inode->i_ino, create);
2846        return _ext4_get_block(inode, iblock, bh_result,
2847                               EXT4_GET_BLOCKS_IO_CREATE_EXT);
2848}
2849
2850static int ext4_get_block_write_nolock(struct inode *inode, sector_t iblock,
2851                   struct buffer_head *bh_result, int flags)
2852{
2853        handle_t *handle = ext4_journal_current_handle();
2854        struct ext4_map_blocks map;
2855        int ret = 0;
2856
2857        ext4_debug("ext4_get_block_write_nolock: inode %lu, flag %d\n",
2858                   inode->i_ino, flags);
2859
2860        flags = EXT4_GET_BLOCKS_NO_LOCK;
2861
2862        map.m_lblk = iblock;
2863        map.m_len = bh_result->b_size >> inode->i_blkbits;
2864
2865        ret = ext4_map_blocks(handle, inode, &map, flags);
2866        if (ret > 0) {
2867                map_bh(bh_result, inode->i_sb, map.m_pblk);
2868                bh_result->b_state = (bh_result->b_state & ~EXT4_MAP_FLAGS) |
2869                                        map.m_flags;
2870                bh_result->b_size = inode->i_sb->s_blocksize * map.m_len;
2871                ret = 0;
2872        }
2873        return ret;
2874}
2875
2876static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
2877                            ssize_t size, void *private, int ret,
2878                            bool is_async)
2879{
2880        struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
2881        ext4_io_end_t *io_end = iocb->private;
2882        struct workqueue_struct *wq;
2883        unsigned long flags;
2884        struct ext4_inode_info *ei;
2885
2886        /* if not async direct IO or dio with 0 bytes write, just return */
2887        if (!io_end || !size)
2888                goto out;
2889
2890        ext_debug("ext4_end_io_dio(): io_end 0x%p "
2891                  "for inode %lu, iocb 0x%p, offset %llu, size %zd\n",
2892                  iocb->private, io_end->inode->i_ino, iocb, offset,
2893                  size);
2894
2895        iocb->private = NULL;
2896
2897        /* if not aio dio with unwritten extents, just free io and return */
2898        if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
2899                ext4_free_io_end(io_end);
2900out:
2901                if (is_async)
2902                        aio_complete(iocb, ret, 0);
2903                inode_dio_done(inode);
2904                return;
2905        }
2906
2907        io_end->offset = offset;
2908        io_end->size = size;
2909        if (is_async) {
2910                io_end->iocb = iocb;
2911                io_end->result = ret;
2912        }
2913        wq = EXT4_SB(io_end->inode->i_sb)->dio_unwritten_wq;
2914
2915        /* Add the io_end to per-inode completed aio dio list*/
2916        ei = EXT4_I(io_end->inode);
2917        spin_lock_irqsave(&ei->i_completed_io_lock, flags);
2918        list_add_tail(&io_end->list, &ei->i_completed_io_list);
2919        spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
2920
2921        /* queue the work to convert unwritten extents to written */
2922        queue_work(wq, &io_end->work);
2923}
2924
2925static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate)
2926{
2927        ext4_io_end_t *io_end = bh->b_private;
2928        struct workqueue_struct *wq;
2929        struct inode *inode;
2930        unsigned long flags;
2931
2932        if (!test_clear_buffer_uninit(bh) || !io_end)
2933                goto out;
2934
2935        if (!(io_end->inode->i_sb->s_flags & MS_ACTIVE)) {
2936                ext4_msg(io_end->inode->i_sb, KERN_INFO,
2937                         "sb umounted, discard end_io request for inode %lu",
2938                         io_end->inode->i_ino);
2939                ext4_free_io_end(io_end);
2940                goto out;
2941        }
2942
2943        /*
2944         * It may be over-defensive here to check EXT4_IO_END_UNWRITTEN now,
2945         * but being more careful is always safe for the future change.
2946         */
2947        inode = io_end->inode;
2948        ext4_set_io_unwritten_flag(inode, io_end);
2949
2950        /* Add the io_end to per-inode completed io list*/
2951        spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
2952        list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list);
2953        spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags);
2954
2955        wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq;
2956        /* queue the work to convert unwritten extents to written */
2957        queue_work(wq, &io_end->work);
2958out:
2959        bh->b_private = NULL;
2960        bh->b_end_io = NULL;
2961        clear_buffer_uninit(bh);
2962        end_buffer_async_write(bh, uptodate);
2963}
2964
2965static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode)
2966{
2967        ext4_io_end_t *io_end;
2968        struct page *page = bh->b_page;
2969        loff_t offset = (sector_t)page->index << PAGE_CACHE_SHIFT;
2970        size_t size = bh->b_size;
2971
2972retry:
2973        io_end = ext4_init_io_end(inode, GFP_ATOMIC);
2974        if (!io_end) {
2975                pr_warn_ratelimited("%s: allocation fail\n", __func__);
2976                schedule();
2977                goto retry;
2978        }
2979        io_end->offset = offset;
2980        io_end->size = size;
2981        /*
2982         * We need to hold a reference to the page to make sure it
2983         * doesn't get evicted before ext4_end_io_work() has a chance
2984         * to convert the extent from written to unwritten.
2985         */
2986        io_end->page = page;
2987        get_page(io_end->page);
2988
2989        bh->b_private = io_end;
2990        bh->b_end_io = ext4_end_io_buffer_write;
2991        return 0;
2992}
2993
2994/*
2995 * For ext4 extent files, ext4 will do direct-io write to holes,
2996 * preallocated extents, and those write extend the file, no need to
2997 * fall back to buffered IO.
2998 *
2999 * For holes, we fallocate those blocks, mark them as uninitialized
3000 * If those blocks were preallocated, we mark sure they are splited, but
3001 * still keep the range to write as uninitialized.
3002 *
3003 * The unwrritten extents will be converted to written when DIO is completed.
3004 * For async direct IO, since the IO may still pending when return, we
3005 * set up an end_io call back function, which will do the conversion
3006 * when async direct IO completed.
3007 *
3008 * If the O_DIRECT write will extend the file then add this inode to the
3009 * orphan list.  So recovery will truncate it back to the original size
3010 * if the machine crashes during the write.
3011 *
3012 */
3013static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
3014                              const struct iovec *iov, loff_t offset,
3015                              unsigned long nr_segs)
3016{
3017        struct file *file = iocb->ki_filp;
3018        struct inode *inode = file->f_mapping->host;
3019        ssize_t ret;
3020        size_t count = iov_length(iov, nr_segs);
3021
3022        loff_t final_size = offset + count;
3023        if (rw == WRITE && final_size <= inode->i_size) {
3024                int overwrite = 0;
3025
3026                BUG_ON(iocb->private == NULL);
3027
3028                /* If we do a overwrite dio, i_mutex locking can be released */
3029                overwrite = *((int *)iocb->private);
3030
3031                if (overwrite) {
3032                        down_read(&EXT4_I(inode)->i_data_sem);
3033                        mutex_unlock(&inode->i_mutex);
3034                }
3035
3036                /*
3037                 * We could direct write to holes and fallocate.
3038                 *
3039                 * Allocated blocks to fill the hole are marked as uninitialized
3040                 * to prevent parallel buffered read to expose the stale data
3041                 * before DIO complete the data IO.
3042                 *
3043                 * As to previously fallocated extents, ext4 get_block
3044                 * will just simply mark the buffer mapped but still
3045                 * keep the extents uninitialized.
3046                 *
3047                 * for non AIO case, we will convert those unwritten extents
3048                 * to written after return back from blockdev_direct_IO.
3049                 *
3050                 * for async DIO, the conversion needs to be defered when
3051                 * the IO is completed. The ext4 end_io callback function
3052                 * will be called to take care of the conversion work.
3053                 * Here for async case, we allocate an io_end structure to
3054                 * hook to the iocb.
3055                 */
3056                iocb->private = NULL;
3057                EXT4_I(inode)->cur_aio_dio = NULL;
3058                if (!is_sync_kiocb(iocb)) {
3059                        ext4_io_end_t *io_end =
3060                                ext4_init_io_end(inode, GFP_NOFS);
3061                        if (!io_end) {
3062                                ret = -ENOMEM;
3063                                goto retake_lock;
3064                        }
3065                        io_end->flag |= EXT4_IO_END_DIRECT;
3066                        iocb->private = io_end;
3067                        /*
3068                         * we save the io structure for current async
3069                         * direct IO, so that later ext4_map_blocks()
3070                         * could flag the io structure whether there
3071                         * is a unwritten extents needs to be converted
3072                         * when IO is completed.
3073                         */
3074                        EXT4_I(inode)->cur_aio_dio = iocb->private;
3075                }
3076
3077                if (overwrite)
3078                        ret = __blockdev_direct_IO(rw, iocb, inode,
3079                                                 inode->i_sb->s_bdev, iov,
3080                                                 offset, nr_segs,
3081                                                 ext4_get_block_write_nolock,
3082                                                 ext4_end_io_dio,
3083                                                 NULL,
3084                                                 0);
3085                else
3086                        ret = __blockdev_direct_IO(rw, iocb, inode,
3087                                                 inode->i_sb->s_bdev, iov,
3088                                                 offset, nr_segs,
3089                                                 ext4_get_block_write,
3090                                                 ext4_end_io_dio,
3091                                                 NULL,
3092                                                 DIO_LOCKING);
3093                if (iocb->private)
3094                        EXT4_I(inode)->cur_aio_dio = NULL;
3095                /*
3096                 * The io_end structure takes a reference to the inode,
3097                 * that structure needs to be destroyed and the
3098                 * reference to the inode need to be dropped, when IO is
3099                 * complete, even with 0 byte write, or failed.
3100                 *
3101                 * In the successful AIO DIO case, the io_end structure will be
3102                 * desctroyed and the reference to the inode will be dropped
3103                 * after the end_io call back function is called.
3104                 *
3105                 * In the case there is 0 byte write, or error case, since
3106                 * VFS direct IO won't invoke the end_io call back function,
3107                 * we need to free the end_io structure here.
3108                 */
3109                if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) {
3110                        ext4_free_io_end(iocb->private);
3111                        iocb->private = NULL;
3112                } else if (ret > 0 && !overwrite && ext4_test_inode_state(inode,
3113                                                EXT4_STATE_DIO_UNWRITTEN)) {
3114                        int err;
3115                        /*
3116                         * for non AIO case, since the IO is already
3117                         * completed, we could do the conversion right here
3118                         */
3119                        err = ext4_convert_unwritten_extents(inode,
3120                                                             offset, ret);
3121                        if (err < 0)
3122                                ret = err;
3123                        ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3124                }
3125
3126        retake_lock:
3127                /* take i_mutex locking again if we do a ovewrite dio */
3128                if (overwrite) {
3129                        up_read(&EXT4_I(inode)->i_data_sem);
3130                        mutex_lock(&inode->i_mutex);
3131                }
3132
3133                return ret;
3134        }
3135
3136        /* for write the the end of file case, we fall back to old way */
3137        return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
3138}
3139
3140static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
3141                              const struct iovec *iov, loff_t offset,
3142                              unsigned long nr_segs)
3143{
3144        struct file *file = iocb->ki_filp;
3145        struct inode *inode = file->f_mapping->host;
3146        ssize_t ret;
3147
3148        /*
3149         * If we are doing data journalling we don't support O_DIRECT
3150         */
3151        if (ext4_should_journal_data(inode))
3152                return 0;
3153
3154        trace_ext4_direct_IO_enter(inode, offset, iov_length(iov, nr_segs), rw);
3155        if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3156                ret = ext4_ext_direct_IO(rw, iocb, iov, offset, nr_segs);
3157        else
3158                ret = ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
3159        trace_ext4_direct_IO_exit(inode, offset,
3160                                iov_length(iov, nr_segs), rw, ret);
3161        return ret;
3162}
3163
3164/*
3165 * Pages can be marked dirty completely asynchronously from ext4's journalling
3166 * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
3167 * much here because ->set_page_dirty is called under VFS locks.  The page is
3168 * not necessarily locked.
3169 *
3170 * We cannot just dirty the page and leave attached buffers clean, because the
3171 * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
3172 * or jbddirty because all the journalling code will explode.
3173 *
3174 * So what we do is to mark the page "pending dirty" and next time writepage
3175 * is called, propagate that into the buffers appropriately.
3176 */
3177static int ext4_journalled_set_page_dirty(struct page *page)
3178{
3179        SetPageChecked(page);
3180        return __set_page_dirty_nobuffers(page);
3181}
3182
3183static const struct address_space_operations ext4_ordered_aops = {
3184        .readpage               = ext4_readpage,
3185        .readpages              = ext4_readpages,
3186        .writepage              = ext4_writepage,
3187        .write_begin            = ext4_write_begin,
3188        .write_end              = ext4_ordered_write_end,
3189        .bmap                   = ext4_bmap,
3190        .invalidatepage         = ext4_invalidatepage,
3191        .releasepage            = ext4_releasepage,
3192        .direct_IO              = ext4_direct_IO,
3193        .migratepage            = buffer_migrate_page,
3194        .is_partially_uptodate  = block_is_partially_uptodate,
3195        .error_remove_page      = generic_error_remove_page,
3196};
3197
3198static const struct address_space_operations ext4_writeback_aops = {
3199        .readpage               = ext4_readpage,
3200        .readpages              = ext4_readpages,
3201        .writepage              = ext4_writepage,
3202        .write_begin            = ext4_write_begin,
3203        .write_end              = ext4_writeback_write_end,
3204        .bmap                   = ext4_bmap,
3205        .invalidatepage         = ext4_invalidatepage,
3206        .releasepage            = ext4_releasepage,
3207        .direct_IO              = ext4_direct_IO,
3208        .migratepage            = buffer_migrate_page,
3209        .is_partially_uptodate  = block_is_partially_uptodate,
3210        .error_remove_page      = generic_error_remove_page,
3211};
3212
3213static const struct address_space_operations ext4_journalled_aops = {
3214        .readpage               = ext4_readpage,
3215        .readpages              = ext4_readpages,
3216        .writepage              = ext4_writepage,
3217        .write_begin            = ext4_write_begin,
3218        .write_end              = ext4_journalled_write_end,
3219        .set_page_dirty         = ext4_journalled_set_page_dirty,
3220        .bmap                   = ext4_bmap,
3221        .invalidatepage         = ext4_invalidatepage,
3222        .releasepage            = ext4_releasepage,
3223        .direct_IO              = ext4_direct_IO,
3224        .is_partially_uptodate  = block_is_partially_uptodate,
3225        .error_remove_page      = generic_error_remove_page,
3226};
3227
3228static const struct address_space_operations ext4_da_aops = {
3229        .readpage               = ext4_readpage,
3230        .readpages              = ext4_readpages,
3231        .writepage              = ext4_writepage,
3232        .writepages             = ext4_da_writepages,
3233        .write_begin            = ext4_da_write_begin,
3234        .write_end              = ext4_da_write_end,
3235        .bmap                   = ext4_bmap,
3236        .invalidatepage         = ext4_da_invalidatepage,
3237        .releasepage            = ext4_releasepage,
3238        .direct_IO              = ext4_direct_IO,
3239        .migratepage            = buffer_migrate_page,
3240        .is_partially_uptodate  = block_is_partially_uptodate,
3241        .error_remove_page      = generic_error_remove_page,
3242};
3243
3244void ext4_set_aops(struct inode *inode)
3245{
3246        switch (ext4_inode_journal_mode(inode)) {
3247        case EXT4_INODE_ORDERED_DATA_MODE:
3248                if (test_opt(inode->i_sb, DELALLOC))
3249                        inode->i_mapping->a_ops = &ext4_da_aops;
3250                else
3251                        inode->i_mapping->a_ops = &ext4_ordered_aops;
3252                break;
3253        case EXT4_INODE_WRITEBACK_DATA_MODE:
3254                if (test_opt(inode->i_sb, DELALLOC))
3255                        inode->i_mapping->a_ops = &ext4_da_aops;
3256                else
3257                        inode->i_mapping->a_ops = &ext4_writeback_aops;
3258                break;
3259        case EXT4_INODE_JOURNAL_DATA_MODE:
3260                inode->i_mapping->a_ops = &ext4_journalled_aops;
3261                break;
3262        default:
3263                BUG();
3264        }
3265}
3266
3267
3268/*
3269 * ext4_discard_partial_page_buffers()
3270 * Wrapper function for ext4_discard_partial_page_buffers_no_lock.
3271 * This function finds and locks the page containing the offset
3272 * "from" and passes it to ext4_discard_partial_page_buffers_no_lock.
3273 * Calling functions that already have the page locked should call
3274 * ext4_discard_partial_page_buffers_no_lock directly.
3275 */
3276int ext4_discard_partial_page_buffers(handle_t *handle,
3277                struct address_space *mapping, loff_t from,
3278                loff_t length, int flags)
3279{
3280        struct inode *inode = mapping->host;
3281        struct page *page;
3282        int err = 0;
3283
3284        page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT,
3285                                   mapping_gfp_mask(mapping) & ~__GFP_FS);
3286        if (!page)
3287                return -ENOMEM;
3288
3289        err = ext4_discard_partial_page_buffers_no_lock(handle, inode, page,
3290                from, length, flags);
3291
3292        unlock_page(page);
3293        page_cache_release(page);
3294        return err;
3295}
3296
3297/*
3298 * ext4_discard_partial_page_buffers_no_lock()
3299 * Zeros a page range of length 'length' starting from offset 'from'.
3300 * Buffer heads that correspond to the block aligned regions of the
3301 * zeroed range will be unmapped.  Unblock aligned regions
3302 * will have the corresponding buffer head mapped if needed so that
3303 * that region of the page can be updated with the partial zero out.
3304 *
3305 * This function assumes that the page has already been  locked.  The
3306 * The range to be discarded must be contained with in the given page.
3307 * If the specified range exceeds the end of the page it will be shortened
3308 * to the end of the page that corresponds to 'from'.  This function is
3309 * appropriate for updating a page and it buffer heads to be unmapped and
3310 * zeroed for blocks that have been either released, or are going to be
3311 * released.
3312 *
3313 * handle: The journal handle
3314 * inode:  The files inode
3315 * page:   A locked page that contains the offset "from"
3316 * from:   The starting byte offset (from the begining of the file)
3317 *         to begin discarding
3318 * len:    The length of bytes to discard
3319 * flags:  Optional flags that may be used:
3320 *
3321 *         EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED
3322 *         Only zero the regions of the page whose buffer heads
3323 *         have already been unmapped.  This flag is appropriate
3324 *         for updateing the contents of a page whose blocks may
3325 *         have already been released, and we only want to zero
3326 *         out the regions that correspond to those released blocks.
3327 *
3328 * Returns zero on sucess or negative on failure.
3329 */
3330static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle,
3331                struct inode *inode, struct page *page, loff_t from,
3332                loff_t length, int flags)
3333{
3334        ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
3335        unsigned int offset = from & (PAGE_CACHE_SIZE-1);
3336        unsigned int blocksize, max, pos;
3337        ext4_lblk_t iblock;
3338        struct buffer_head *bh;
3339        int err = 0;
3340
3341        blocksize = inode->i_sb->s_blocksize;
3342        max = PAGE_CACHE_SIZE - offset;
3343
3344        if (index != page->index)
3345                return -EINVAL;
3346
3347        /*
3348         * correct length if it does not fall between
3349         * 'from' and the end of the page
3350         */
3351        if (length > max || length < 0)
3352                length = max;
3353
3354        iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
3355
3356        if (!page_has_buffers(page))
3357                create_empty_buffers(page, blocksize, 0);
3358
3359        /* Find the buffer that contains "offset" */
3360        bh = page_buffers(page);
3361        pos = blocksize;
3362        while (offset >= pos) {
3363                bh = bh->b_this_page;
3364                iblock++;
3365                pos += blocksize;
3366        }
3367
3368        pos = offset;
3369        while (pos < offset + length) {
3370                unsigned int end_of_block, range_to_discard;
3371
3372                err = 0;
3373
3374                /* The length of space left to zero and unmap */
3375                range_to_discard = offset + length - pos;
3376
3377                /* The length of space until the end of the block */
3378                end_of_block = blocksize - (pos & (blocksize-1));
3379
3380                /*
3381                 * Do not unmap or zero past end of block
3382                 * for this buffer head
3383                 */
3384                if (range_to_discard > end_of_block)
3385                        range_to_discard = end_of_block;
3386
3387
3388                /*
3389                 * Skip this buffer head if we are only zeroing unampped
3390                 * regions of the page
3391                 */
3392                if (flags & EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED &&
3393                        buffer_mapped(bh))
3394                                goto next;
3395
3396                /* If the range is block aligned, unmap */
3397                if (range_to_discard == blocksize) {
3398                        clear_buffer_dirty(bh);
3399                        bh->b_bdev = NULL;
3400                        clear_buffer_mapped(bh);
3401                        clear_buffer_req(bh);
3402                        clear_buffer_new(bh);
3403                        clear_buffer_delay(bh);
3404                        clear_buffer_unwritten(bh);
3405                        clear_buffer_uptodate(bh);
3406                        zero_user(page, pos, range_to_discard);
3407                        BUFFER_TRACE(bh, "Buffer discarded");
3408                        goto next;
3409                }
3410
3411                /*
3412                 * If this block is not completely contained in the range
3413                 * to be discarded, then it is not going to be released. Because
3414                 * we need to keep this block, we need to make sure this part
3415                 * of the page is uptodate before we modify it by writeing
3416                 * partial zeros on it.
3417                 */
3418                if (!buffer_mapped(bh)) {
3419                        /*
3420                         * Buffer head must be mapped before we can read
3421                         * from the block
3422                         */
3423                        BUFFER_TRACE(bh, "unmapped");
3424                        ext4_get_block(inode, iblock, bh, 0);
3425                        /* unmapped? It's a hole - nothing to do */
3426                        if (!buffer_mapped(bh)) {
3427                                BUFFER_TRACE(bh, "still unmapped");
3428                                goto next;
3429                        }
3430                }
3431
3432                /* Ok, it's mapped. Make sure it's up-to-date */
3433                if (PageUptodate(page))
3434                        set_buffer_uptodate(bh);
3435
3436                if (!buffer_uptodate(bh)) {
3437                        err = -EIO;
3438                        ll_rw_block(READ, 1, &bh);
3439                        wait_on_buffer(bh);
3440                        /* Uhhuh. Read error. Complain and punt.*/
3441                        if (!buffer_uptodate(bh))
3442                                goto next;
3443                }
3444
3445                if (ext4_should_journal_data(inode)) {
3446                        BUFFER_TRACE(bh, "get write access");
3447                        err = ext4_journal_get_write_access(handle, bh);
3448                        if (err)
3449                                goto next;
3450                }
3451
3452                zero_user(page, pos, range_to_discard);
3453
3454                err = 0;
3455                if (ext4_should_journal_data(inode)) {
3456                        err = ext4_handle_dirty_metadata(handle, inode, bh);
3457                } else
3458                        mark_buffer_dirty(bh);
3459
3460                BUFFER_TRACE(bh, "Partial buffer zeroed");
3461next:
3462                bh = bh->b_this_page;
3463                iblock++;
3464                pos += range_to_discard;
3465        }
3466
3467        return err;
3468}
3469
3470int ext4_can_truncate(struct inode *inode)
3471{
3472        if (S_ISREG(inode->i_mode))
3473                return 1;
3474        if (S_ISDIR(inode->i_mode))
3475                return 1;
3476        if (S_ISLNK(inode->i_mode))
3477                return !ext4_inode_is_fast_symlink(inode);
3478        return 0;
3479}
3480
3481/*
3482 * ext4_punch_hole: punches a hole in a file by releaseing the blocks
3483 * associated with the given offset and length
3484 *
3485 * @inode:  File inode
3486 * @offset: The offset where the hole will begin
3487 * @len:    The length of the hole
3488 *
3489 * Returns: 0 on sucess or negative on failure
3490 */
3491
3492int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
3493{
3494        struct inode *inode = file->f_path.dentry->d_inode;
3495        if (!S_ISREG(inode->i_mode))
3496                return -EOPNOTSUPP;
3497
3498        if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
3499                /* TODO: Add support for non extent hole punching */
3500                return -EOPNOTSUPP;
3501        }
3502
3503        if (EXT4_SB(inode->i_sb)->s_cluster_ratio > 1) {
3504                /* TODO: Add support for bigalloc file systems */
3505                return -EOPNOTSUPP;
3506        }
3507
3508        return ext4_ext_punch_hole(file, offset, length);
3509}
3510
3511/*
3512 * ext4_truncate()
3513 *
3514 * We block out ext4_get_block() block instantiations across the entire
3515 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
3516 * simultaneously on behalf of the same inode.
3517 *
3518 * As we work through the truncate and commit bits of it to the journal there
3519 * is one core, guiding principle: the file's tree must always be consistent on
3520 * disk.  We must be able to restart the truncate after a crash.
3521 *
3522 * The file's tree may be transiently inconsistent in memory (although it
3523 * probably isn't), but whenever we close off and commit a journal transaction,
3524 * the contents of (the filesystem + the journal) must be consistent and
3525 * restartable.  It's pretty simple, really: bottom up, right to left (although
3526 * left-to-right works OK too).
3527 *
3528 * Note that at recovery time, journal replay occurs *before* the restart of
3529 * truncate against the orphan inode list.
3530 *
3531 * The committed inode has the new, desired i_size (which is the same as
3532 * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
3533 * that this inode's truncate did not complete and it will again call
3534 * ext4_truncate() to have another go.  So there will be instantiated blocks
3535 * to the right of the truncation point in a crashed ext4 filesystem.  But
3536 * that's fine - as long as they are linked from the inode, the post-crash
3537 * ext4_truncate() run will find them and release them.
3538 */
3539void ext4_truncate(struct inode *inode)
3540{
3541        trace_ext4_truncate_enter(inode);
3542
3543        if (!ext4_can_truncate(inode))
3544                return;
3545
3546        ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3547
3548        if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
3549                ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
3550
3551        if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3552                ext4_ext_truncate(inode);
3553        else
3554                ext4_ind_truncate(inode);
3555
3556        trace_ext4_truncate_exit(inode);
3557}
3558
3559/*
3560 * ext4_get_inode_loc returns with an extra refcount against the inode's
3561 * underlying buffer_head on success. If 'in_mem' is true, we have all
3562 * data in memory that is needed to recreate the on-disk version of this
3563 * inode.
3564 */
3565static int __ext4_get_inode_loc(struct inode *inode,
3566                                struct ext4_iloc *iloc, int in_mem)
3567{
3568        struct ext4_group_desc  *gdp;
3569        struct buffer_head      *bh;
3570        struct super_block      *sb = inode->i_sb;
3571        ext4_fsblk_t            block;
3572        int                     inodes_per_block, inode_offset;
3573
3574        iloc->bh = NULL;
3575        if (!ext4_valid_inum(sb, inode->i_ino))
3576                return -EIO;
3577
3578        iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
3579        gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
3580        if (!gdp)
3581                return -EIO;
3582
3583        /*
3584         * Figure out the offset within the block group inode table
3585         */
3586        inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
3587        inode_offset = ((inode->i_ino - 1) %
3588                        EXT4_INODES_PER_GROUP(sb));
3589        block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
3590        iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
3591
3592        bh = sb_getblk(sb, block);
3593        if (!bh) {
3594                EXT4_ERROR_INODE_BLOCK(inode, block,
3595                                       "unable to read itable block");
3596                return -EIO;
3597        }
3598        if (!buffer_uptodate(bh)) {
3599                lock_buffer(bh);
3600
3601                /*
3602                 * If the buffer has the write error flag, we have failed
3603                 * to write out another inode in the same block.  In this
3604                 * case, we don't have to read the block because we may
3605                 * read the old inode data successfully.
3606                 */
3607                if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
3608                        set_buffer_uptodate(bh);
3609
3610                if (buffer_uptodate(bh)) {
3611                        /* someone brought it uptodate while we waited */
3612                        unlock_buffer(bh);
3613                        goto has_buffer;
3614                }
3615
3616                /*
3617                 * If we have all information of the inode in memory and this
3618                 * is the only valid inode in the block, we need not read the
3619                 * block.
3620                 */
3621                if (in_mem) {
3622                        struct buffer_head *bitmap_bh;
3623                        int i, start;
3624
3625                        start = inode_offset & ~(inodes_per_block - 1);
3626
3627                        /* Is the inode bitmap in cache? */
3628                        bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
3629                        if (!bitmap_bh)
3630                                goto make_io;
3631
3632                        /*
3633                         * If the inode bitmap isn't in cache then the
3634                         * optimisation may end up performing two reads instead
3635                         * of one, so skip it.
3636                         */
3637                        if (!buffer_uptodate(bitmap_bh)) {
3638                                brelse(bitmap_bh);
3639                                goto make_io;
3640                        }
3641                        for (i = start; i < start + inodes_per_block; i++) {
3642                                if (i == inode_offset)
3643                                        continue;
3644                                if (ext4_test_bit(i, bitmap_bh->b_data))
3645                                        break;
3646                        }
3647                        brelse(bitmap_bh);
3648                        if (i == start + inodes_per_block) {
3649                                /* all other inodes are free, so skip I/O */
3650                                memset(bh->b_data, 0, bh->b_size);
3651                                set_buffer_uptodate(bh);
3652                                unlock_buffer(bh);
3653                                goto has_buffer;
3654                        }
3655                }
3656
3657make_io:
3658                /*
3659                 * If we need to do any I/O, try to pre-readahead extra
3660                 * blocks from the inode table.
3661                 */
3662                if (EXT4_SB(sb)->s_inode_readahead_blks) {
3663                        ext4_fsblk_t b, end, table;
3664                        unsigned num;
3665
3666                        table = ext4_inode_table(sb, gdp);
3667                        /* s_inode_readahead_blks is always a power of 2 */
3668                        b = block & ~(EXT4_SB(sb)->s_inode_readahead_blks-1);
3669                        if (table > b)
3670                                b = table;
3671                        end = b + EXT4_SB(sb)->s_inode_readahead_blks;
3672                        num = EXT4_INODES_PER_GROUP(sb);
3673                        if (ext4_has_group_desc_csum(sb))
3674                                num -= ext4_itable_unused_count(sb, gdp);
3675                        table += num / inodes_per_block;
3676                        if (end > table)
3677                                end = table;
3678                        while (b <= end)
3679                                sb_breadahead(sb, b++);
3680                }
3681
3682                /*
3683                 * There are other valid inodes in the buffer, this inode
3684                 * has in-inode xattrs, or we don't have this inode in memory.
3685                 * Read the block from disk.
3686                 */
3687                trace_ext4_load_inode(inode);
3688                get_bh(bh);
3689                bh->b_end_io = end_buffer_read_sync;
3690                submit_bh(READ | REQ_META | REQ_PRIO, bh);
3691                wait_on_buffer(bh);
3692                if (!buffer_uptodate(bh)) {
3693                        EXT4_ERROR_INODE_BLOCK(inode, block,
3694                                               "unable to read itable block");
3695                        brelse(bh);
3696                        return -EIO;
3697                }
3698        }
3699has_buffer:
3700        iloc->bh = bh;
3701        return 0;
3702}
3703
3704int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
3705{
3706        /* We have all inode data except xattrs in memory here. */
3707        return __ext4_get_inode_loc(inode, iloc,
3708                !ext4_test_inode_state(inode, EXT4_STATE_XATTR));
3709}
3710
3711void ext4_set_inode_flags(struct inode *inode)
3712{
3713        unsigned int flags = EXT4_I(inode)->i_flags;
3714
3715        inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
3716        if (flags & EXT4_SYNC_FL)
3717                inode->i_flags |= S_SYNC;
3718        if (flags & EXT4_APPEND_FL)
3719                inode->i_flags |= S_APPEND;
3720        if (flags & EXT4_IMMUTABLE_FL)
3721                inode->i_flags |= S_IMMUTABLE;
3722        if (flags & EXT4_NOATIME_FL)
3723                inode->i_flags |= S_NOATIME;
3724        if (flags & EXT4_DIRSYNC_FL)
3725                inode->i_flags |= S_DIRSYNC;
3726}
3727
3728/* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
3729void ext4_get_inode_flags(struct ext4_inode_info *ei)
3730{
3731        unsigned int vfs_fl;
3732        unsigned long old_fl, new_fl;
3733
3734        do {
3735                vfs_fl = ei->vfs_inode.i_flags;
3736                old_fl = ei->i_flags;
3737                new_fl = old_fl & ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
3738                                EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|
3739                                EXT4_DIRSYNC_FL);
3740                if (vfs_fl & S_SYNC)
3741                        new_fl |= EXT4_SYNC_FL;
3742                if (vfs_fl & S_APPEND)
3743                        new_fl |= EXT4_APPEND_FL;
3744                if (vfs_fl & S_IMMUTABLE)
3745                        new_fl |= EXT4_IMMUTABLE_FL;
3746                if (vfs_fl & S_NOATIME)
3747                        new_fl |= EXT4_NOATIME_FL;
3748                if (vfs_fl & S_DIRSYNC)
3749                        new_fl |= EXT4_DIRSYNC_FL;
3750        } while (cmpxchg(&ei->i_flags, old_fl, new_fl) != old_fl);
3751}
3752
3753static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
3754                                  struct ext4_inode_info *ei)
3755{
3756        blkcnt_t i_blocks ;
3757        struct inode *inode = &(ei->vfs_inode);
3758        struct super_block *sb = inode->i_sb;
3759
3760        if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3761                                EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
3762                /* we are using combined 48 bit field */
3763                i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
3764                                        le32_to_cpu(raw_inode->i_blocks_lo);
3765                if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
3766                        /* i_blocks represent file system block size */
3767                        return i_blocks  << (inode->i_blkbits - 9);
3768                } else {
3769                        return i_blocks;
3770                }
3771        } else {
3772                return le32_to_cpu(raw_inode->i_blocks_lo);
3773        }
3774}
3775
3776struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
3777{
3778        struct ext4_iloc iloc;
3779        struct ext4_inode *raw_inode;
3780        struct ext4_inode_info *ei;
3781        struct inode *inode;
3782        journal_t *journal = EXT4_SB(sb)->s_journal;
3783        long ret;
3784        int block;
3785        uid_t i_uid;
3786        gid_t i_gid;
3787
3788        inode = iget_locked(sb, ino);
3789        if (!inode)
3790                return ERR_PTR(-ENOMEM);
3791        if (!(inode->i_state & I_NEW))
3792                return inode;
3793
3794        ei = EXT4_I(inode);
3795        iloc.bh = NULL;
3796
3797        ret = __ext4_get_inode_loc(inode, &iloc, 0);
3798        if (ret < 0)
3799                goto bad_inode;
3800        raw_inode = ext4_raw_inode(&iloc);
3801
3802        if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
3803                ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
3804                if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
3805                    EXT4_INODE_SIZE(inode->i_sb)) {
3806                        EXT4_ERROR_INODE(inode, "bad extra_isize (%u != %u)",
3807                                EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize,
3808                                EXT4_INODE_SIZE(inode->i_sb));
3809                        ret = -EIO;
3810                        goto bad_inode;
3811                }
3812        } else
3813                ei->i_extra_isize = 0;
3814
3815        /* Precompute checksum seed for inode metadata */
3816        if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3817                        EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
3818                struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3819                __u32 csum;
3820                __le32 inum = cpu_to_le32(inode->i_ino);
3821                __le32 gen = raw_inode->i_generation;
3822                csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
3823                                   sizeof(inum));
3824                ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
3825                                              sizeof(gen));
3826        }
3827
3828        if (!ext4_inode_csum_verify(inode, raw_inode, ei)) {
3829                EXT4_ERROR_INODE(inode, "checksum invalid");
3830                ret = -EIO;
3831                goto bad_inode;
3832        }
3833
3834        inode->i_mode = le16_to_cpu(raw_inode->i_mode);
3835        i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
3836        i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
3837        if (!(test_opt(inode->i_sb, NO_UID32))) {
3838                i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
3839                i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
3840        }
3841        i_uid_write(inode, i_uid);
3842        i_gid_write(inode, i_gid);
3843        set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
3844
3845        ext4_clear_state_flags(ei);     /* Only relevant on 32-bit archs */
3846        ei->i_dir_start_lookup = 0;
3847        ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
3848        /* We now have enough fields to check if the inode was active or not.
3849         * This is needed because nfsd might try to access dead inodes
3850         * the test is that same one that e2fsck uses
3851         * NeilBrown 1999oct15
3852         */
3853        if (inode->i_nlink == 0) {
3854                if (inode->i_mode == 0 ||
3855                    !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
3856                        /* this inode is deleted */
3857                        ret = -ESTALE;
3858                        goto bad_inode;
3859                }
3860                /* The only unlinked inodes we let through here have
3861                 * valid i_mode and are being read by the orphan
3862                 * recovery code: that's fine, we're about to complete
3863                 * the process of deleting those. */
3864        }
3865        ei->i_flags = le32_to_cpu(raw_inode->i_flags);
3866        inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
3867        ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
3868        if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT))
3869                ei->i_file_acl |=
3870                        ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
3871        inode->i_size = ext4_isize(raw_inode);
3872        ei->i_disksize = inode->i_size;
3873#ifdef CONFIG_QUOTA
3874        ei->i_reserved_quota = 0;
3875#endif
3876        inode->i_generation = le32_to_cpu(raw_inode->i_generation);
3877        ei->i_block_group = iloc.block_group;
3878        ei->i_last_alloc_group = ~0;
3879        /*
3880         * NOTE! The in-memory inode i_data array is in little-endian order
3881         * even on big-endian machines: we do NOT byteswap the block numbers!
3882         */
3883        for (block = 0; block < EXT4_N_BLOCKS; block++)
3884                ei->i_data[block] = raw_inode->i_block[block];
3885        INIT_LIST_HEAD(&ei->i_orphan);
3886
3887        /*
3888         * Set transaction id's of transactions that have to be committed
3889         * to finish f[data]sync. We set them to currently running transaction
3890         * as we cannot be sure that the inode or some of its metadata isn't
3891         * part of the transaction - the inode could have been reclaimed and
3892         * now it is reread from disk.
3893         */
3894        if (journal) {
3895                transaction_t *transaction;
3896                tid_t tid;
3897
3898                read_lock(&journal->j_state_lock);
3899                if (journal->j_running_transaction)
3900                        transaction = journal->j_running_transaction;
3901                else
3902                        transaction = journal->j_committing_transaction;
3903                if (transaction)
3904                        tid = transaction->t_tid;
3905                else
3906                        tid = journal->j_commit_sequence;
3907                read_unlock(&journal->j_state_lock);
3908                ei->i_sync_tid = tid;
3909                ei->i_datasync_tid = tid;
3910        }
3911
3912        if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
3913                if (ei->i_extra_isize == 0) {
3914                        /* The extra space is currently unused. Use it. */
3915                        ei->i_extra_isize = sizeof(struct ext4_inode) -
3916                                            EXT4_GOOD_OLD_INODE_SIZE;
3917                } else {
3918                        __le32 *magic = (void *)raw_inode +
3919                                        EXT4_GOOD_OLD_INODE_SIZE +
3920                                        ei->i_extra_isize;
3921                        if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
3922                                ext4_set_inode_state(inode, EXT4_STATE_XATTR);
3923                }
3924        }
3925
3926        EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
3927        EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
3928        EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
3929        EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
3930
3931        inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
3932        if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
3933                if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
3934                        inode->i_version |=
3935                        (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
3936        }
3937
3938        ret = 0;
3939        if (ei->i_file_acl &&
3940            !ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) {
3941                EXT4_ERROR_INODE(inode, "bad extended attribute block %llu",
3942                                 ei->i_file_acl);
3943                ret = -EIO;
3944                goto bad_inode;
3945        } else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
3946                if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
3947                    (S_ISLNK(inode->i_mode) &&
3948                     !ext4_inode_is_fast_symlink(inode)))
3949                        /* Validate extent which is part of inode */
3950                        ret = ext4_ext_check_inode(inode);
3951        } else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
3952                   (S_ISLNK(inode->i_mode) &&
3953                    !ext4_inode_is_fast_symlink(inode))) {
3954                /* Validate block references which are part of inode */
3955                ret = ext4_ind_check_inode(inode);
3956        }
3957        if (ret)
3958                goto bad_inode;
3959
3960        if (S_ISREG(inode->i_mode)) {
3961                inode->i_op = &ext4_file_inode_operations;
3962                inode->i_fop = &ext4_file_operations;
3963                ext4_set_aops(inode);
3964        } else if (S_ISDIR(inode->i_mode)) {
3965                inode->i_op = &ext4_dir_inode_operations;
3966                inode->i_fop = &ext4_dir_operations;
3967        } else if (S_ISLNK(inode->i_mode)) {
3968                if (ext4_inode_is_fast_symlink(inode)) {
3969                        inode->i_op = &ext4_fast_symlink_inode_operations;
3970                        nd_terminate_link(ei->i_data, inode->i_size,
3971                                sizeof(ei->i_data) - 1);
3972                } else {
3973                        inode->i_op = &ext4_symlink_inode_operations;
3974                        ext4_set_aops(inode);
3975                }
3976        } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
3977              S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
3978                inode->i_op = &ext4_special_inode_operations;
3979                if (raw_inode->i_block[0])
3980                        init_special_inode(inode, inode->i_mode,
3981                           old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
3982                else
3983                        init_special_inode(inode, inode->i_mode,
3984                           new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
3985        } else {
3986                ret = -EIO;
3987                EXT4_ERROR_INODE(inode, "bogus i_mode (%o)", inode->i_mode);
3988                goto bad_inode;
3989        }
3990        brelse(iloc.bh);
3991        ext4_set_inode_flags(inode);
3992        unlock_new_inode(inode);
3993        return inode;
3994
3995bad_inode:
3996        brelse(iloc.bh);
3997        iget_failed(inode);
3998        return ERR_PTR(ret);
3999}
4000
4001static int ext4_inode_blocks_set(handle_t *handle,
4002                                struct ext4_inode *raw_inode,
4003                                struct ext4_inode_info *ei)
4004{
4005        struct inode *inode = &(ei->vfs_inode);
4006        u64 i_blocks = inode->i_blocks;
4007        struct super_block *sb = inode->i_sb;
4008
4009        if (i_blocks <= ~0U) {
4010                /*
4011                 * i_blocks can be represnted in a 32 bit variable
4012                 * as multiple of 512 bytes
4013                 */
4014                raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4015                raw_inode->i_blocks_high = 0;
4016                ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4017                return 0;
4018        }
4019        if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE))
4020                return -EFBIG;
4021
4022        if (i_blocks <= 0xffffffffffffULL) {
4023                /*
4024                 * i_blocks can be represented in a 48 bit variable
4025                 * as multiple of 512 bytes
4026                 */
4027                raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4028                raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4029                ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4030        } else {
4031                ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4032                /* i_block is stored in file system block size */
4033                i_blocks = i_blocks >> (inode->i_blkbits - 9);
4034                raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4035                raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4036        }
4037        return 0;
4038}
4039
4040/*
4041 * Post the struct inode info into an on-disk inode location in the
4042 * buffer-cache.  This gobbles the caller's reference to the
4043 * buffer_head in the inode location struct.
4044 *
4045 * The caller must have write access to iloc->bh.
4046 */
4047static int ext4_do_update_inode(handle_t *handle,
4048                                struct inode *inode,
4049                                struct ext4_iloc *iloc)
4050{
4051        struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
4052        struct ext4_inode_info *ei = EXT4_I(inode);
4053        struct buffer_head *bh = iloc->bh;
4054        int err = 0, rc, block;
4055        uid_t i_uid;
4056        gid_t i_gid;
4057
4058        /* For fields not not tracking in the in-memory inode,
4059         * initialise them to zero for new inodes. */
4060        if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
4061                memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
4062
4063        ext4_get_inode_flags(ei);
4064        raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4065        i_uid = i_uid_read(inode);
4066        i_gid = i_gid_read(inode);
4067        if (!(test_opt(inode->i_sb, NO_UID32))) {
4068                raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
4069                raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
4070/*
4071 * Fix up interoperability with old kernels. Otherwise, old inodes get
4072 * re-used with the upper 16 bits of the uid/gid intact
4073 */
4074                if (!ei->i_dtime) {
4075                        raw_inode->i_uid_high =
4076                                cpu_to_le16(high_16_bits(i_uid));
4077                        raw_inode->i_gid_high =
4078                                cpu_to_le16(high_16_bits(i_gid));
4079                } else {
4080                        raw_inode->i_uid_high = 0;
4081                        raw_inode->i_gid_high = 0;
4082                }
4083        } else {
4084                raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(i_uid));
4085                raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(i_gid));
4086                raw_inode->i_uid_high = 0;
4087                raw_inode->i_gid_high = 0;
4088        }
4089        raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
4090
4091        EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
4092        EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
4093        EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
4094        EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
4095
4096        if (ext4_inode_blocks_set(handle, raw_inode, ei))
4097                goto out_brelse;
4098        raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
4099        raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
4100        if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
4101            cpu_to_le32(EXT4_OS_HURD))
4102                raw_inode->i_file_acl_high =
4103                        cpu_to_le16(ei->i_file_acl >> 32);
4104        raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
4105        ext4_isize_set(raw_inode, ei->i_disksize);
4106        if (ei->i_disksize > 0x7fffffffULL) {
4107                struct super_block *sb = inode->i_sb;
4108                if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
4109                                EXT4_FEATURE_RO_COMPAT_LARGE_FILE) ||
4110                                EXT4_SB(sb)->s_es->s_rev_level ==
4111                                cpu_to_le32(EXT4_GOOD_OLD_REV)) {
4112                        /* If this is the first large file
4113                         * created, add a flag to the superblock.
4114                         */
4115                        err = ext4_journal_get_write_access(handle,
4116                                        EXT4_SB(sb)->s_sbh);
4117                        if (err)
4118                                goto out_brelse;
4119                        ext4_update_dynamic_rev(sb);
4120                        EXT4_SET_RO_COMPAT_FEATURE(sb,
4121                                        EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
4122                        ext4_handle_sync(handle);
4123                        err = ext4_handle_dirty_super(handle, sb);
4124                }
4125        }
4126        raw_inode->i_generation = cpu_to_le32(inode->i_generation);
4127        if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
4128                if (old_valid_dev(inode->i_rdev)) {
4129                        raw_inode->i_block[0] =
4130                                cpu_to_le32(old_encode_dev(inode->i_rdev));
4131                        raw_inode->i_block[1] = 0;
4132                } else {
4133                        raw_inode->i_block[0] = 0;
4134                        raw_inode->i_block[1] =
4135                                cpu_to_le32(new_encode_dev(inode->i_rdev));
4136                        raw_inode->i_block[2] = 0;
4137                }
4138        } else
4139                for (block = 0; block < EXT4_N_BLOCKS; block++)
4140                        raw_inode->i_block[block] = ei->i_data[block];
4141
4142        raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
4143        if (ei->i_extra_isize) {
4144                if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4145                        raw_inode->i_version_hi =
4146                        cpu_to_le32(inode->i_version >> 32);
4147                raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
4148        }
4149
4150        ext4_inode_csum_set(inode, raw_inode, ei);
4151
4152        BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
4153        rc = ext4_handle_dirty_metadata(handle, NULL, bh);
4154        if (!err)
4155                err = rc;
4156        ext4_clear_inode_state(inode, EXT4_STATE_NEW);
4157
4158        ext4_update_inode_fsync_trans(handle, inode, 0);
4159out_brelse:
4160        brelse(bh);
4161        ext4_std_error(inode->i_sb, err);
4162        return err;
4163}
4164
4165/*
4166 * ext4_write_inode()
4167 *
4168 * We are called from a few places:
4169 *
4170 * - Within generic_file_write() for O_SYNC files.
4171 *   Here, there will be no transaction running. We wait for any running
4172 *   trasnaction to commit.
4173 *
4174 * - Within sys_sync(), kupdate and such.
4175 *   We wait on commit, if tol to.
4176 *
4177 * - Within prune_icache() (PF_MEMALLOC == true)
4178 *   Here we simply return.  We can't afford to block kswapd on the
4179 *   journal commit.
4180 *
4181 * In all cases it is actually safe for us to return without doing anything,
4182 * because the inode has been copied into a raw inode buffer in
4183 * ext4_mark_inode_dirty().  This is a correctness thing for O_SYNC and for
4184 * knfsd.
4185 *
4186 * Note that we are absolutely dependent upon all inode dirtiers doing the
4187 * right thing: they *must* call mark_inode_dirty() after dirtying info in
4188 * which we are interested.
4189 *
4190 * It would be a bug for them to not do this.  The code:
4191 *
4192 *      mark_inode_dirty(inode)
4193 *      stuff();
4194 *      inode->i_size = expr;
4195 *
4196 * is in error because a kswapd-driven write_inode() could occur while
4197 * `stuff()' is running, and the new i_size will be lost.  Plus the inode
4198 * will no longer be on the superblock's dirty inode list.
4199 */
4200int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
4201{
4202        int err;
4203
4204        if (current->flags & PF_MEMALLOC)
4205                return 0;
4206
4207        if (EXT4_SB(inode->i_sb)->s_journal) {
4208                if (ext4_journal_current_handle()) {
4209                        jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
4210                        dump_stack();
4211                        return -EIO;
4212                }
4213
4214                if (wbc->sync_mode != WB_SYNC_ALL)
4215                        return 0;
4216
4217                err = ext4_force_commit(inode->i_sb);
4218        } else {
4219                struct ext4_iloc iloc;
4220
4221                err = __ext4_get_inode_loc(inode, &iloc, 0);
4222                if (err)
4223                        return err;
4224                if (wbc->sync_mode == WB_SYNC_ALL)
4225                        sync_dirty_buffer(iloc.bh);
4226                if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
4227                        EXT4_ERROR_INODE_BLOCK(inode, iloc.bh->b_blocknr,
4228                                         "IO error syncing inode");
4229                        err = -EIO;
4230                }
4231                brelse(iloc.bh);
4232        }
4233        return err;
4234}
4235
4236/*
4237 * ext4_setattr()
4238 *
4239 * Called from notify_change.
4240 *
4241 * We want to trap VFS attempts to truncate the file as soon as
4242 * possible.  In particular, we want to make sure that when the VFS
4243 * shrinks i_size, we put the inode on the orphan list and modify
4244 * i_disksize immediately, so that during the subsequent flushing of
4245 * dirty pages and freeing of disk blocks, we can guarantee that any
4246 * commit will leave the blocks being flushed in an unused state on
4247 * disk.  (On recovery, the inode will get truncated and the blocks will
4248 * be freed, so we have a strong guarantee that no future commit will
4249 * leave these blocks visible to the user.)
4250 *
4251 * Another thing we have to assure is that if we are in ordered mode
4252 * and inode is still attached to the committing transaction, we must
4253 * we start writeout of all the dirty pages which are being truncated.
4254 * This way we are sure that all the data written in the previous
4255 * transaction are already on disk (truncate waits for pages under
4256 * writeback).
4257 *
4258 * Called with inode->i_mutex down.
4259 */
4260int ext4_setattr(struct dentry *dentry, struct iattr *attr)
4261{
4262        struct inode *inode = dentry->d_inode;
4263        int error, rc = 0;
4264        int orphan = 0;
4265        const unsigned int ia_valid = attr->ia_valid;
4266
4267        error = inode_change_ok(inode, attr);
4268        if (error)
4269                return error;
4270
4271        if (is_quota_modification(inode, attr))
4272                dquot_initialize(inode);
4273        if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
4274            (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
4275                handle_t *handle;
4276
4277                /* (user+group)*(old+new) structure, inode write (sb,
4278                 * inode block, ? - but truncate inode update has it) */
4279                handle = ext4_journal_start(inode, (EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+
4280                                        EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb))+3);
4281                if (IS_ERR(handle)) {
4282                        error = PTR_ERR(handle);
4283                        goto err_out;
4284                }
4285                error = dquot_transfer(inode, attr);
4286                if (error) {
4287                        ext4_journal_stop(handle);
4288                        return error;
4289                }
4290                /* Update corresponding info in inode so that everything is in
4291                 * one transaction */
4292                if (attr->ia_valid & ATTR_UID)
4293                        inode->i_uid = attr->ia_uid;
4294                if (attr->ia_valid & ATTR_GID)
4295                        inode->i_gid = attr->ia_gid;
4296                error = ext4_mark_inode_dirty(handle, inode);
4297                ext4_journal_stop(handle);
4298        }
4299
4300        if (attr->ia_valid & ATTR_SIZE) {
4301                inode_dio_wait(inode);
4302
4303                if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4304                        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4305
4306                        if (attr->ia_size > sbi->s_bitmap_maxbytes)
4307                                return -EFBIG;
4308                }
4309        }
4310
4311        if (S_ISREG(inode->i_mode) &&
4312            attr->ia_valid & ATTR_SIZE &&
4313            (attr->ia_size < inode->i_size)) {
4314                handle_t *handle;
4315
4316                handle = ext4_journal_start(inode, 3);
4317                if (IS_ERR(handle)) {
4318                        error = PTR_ERR(handle);
4319                        goto err_out;
4320                }
4321                if (ext4_handle_valid(handle)) {
4322                        error = ext4_orphan_add(handle, inode);
4323                        orphan = 1;
4324                }
4325                EXT4_I(inode)->i_disksize = attr->ia_size;
4326                rc = ext4_mark_inode_dirty(handle, inode);
4327                if (!error)
4328                        error = rc;
4329                ext4_journal_stop(handle);
4330
4331                if (ext4_should_order_data(inode)) {
4332                        error = ext4_begin_ordered_truncate(inode,
4333                                                            attr->ia_size);
4334                        if (error) {
4335                                /* Do as much error cleanup as possible */
4336                                handle = ext4_journal_start(inode, 3);
4337                                if (IS_ERR(handle)) {
4338                                        ext4_orphan_del(NULL, inode);
4339                                        goto err_out;
4340                                }
4341                                ext4_orphan_del(handle, inode);
4342                                orphan = 0;
4343                                ext4_journal_stop(handle);
4344                                goto err_out;
4345                        }
4346                }
4347        }
4348
4349        if (attr->ia_valid & ATTR_SIZE) {
4350                if (attr->ia_size != i_size_read(inode))
4351                        truncate_setsize(inode, attr->ia_size);
4352                ext4_truncate(inode);
4353        }
4354
4355        if (!rc) {
4356                setattr_copy(inode, attr);
4357                mark_inode_dirty(inode);
4358        }
4359
4360        /*
4361         * If the call to ext4_truncate failed to get a transaction handle at
4362         * all, we need to clean up the in-core orphan list manually.
4363         */
4364        if (orphan && inode->i_nlink)
4365                ext4_orphan_del(NULL, inode);
4366
4367        if (!rc && (ia_valid & ATTR_MODE))
4368                rc = ext4_acl_chmod(inode);
4369
4370err_out:
4371        ext4_std_error(inode->i_sb, error);
4372        if (!error)
4373                error = rc;
4374        return error;
4375}
4376
4377int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
4378                 struct kstat *stat)
4379{
4380        struct inode *inode;
4381        unsigned long delalloc_blocks;
4382
4383        inode = dentry->d_inode;
4384        generic_fillattr(inode, stat);
4385
4386        /*
4387         * We can't update i_blocks if the block allocation is delayed
4388         * otherwise in the case of system crash before the real block
4389         * allocation is done, we will have i_blocks inconsistent with
4390         * on-disk file blocks.
4391         * We always keep i_blocks updated together with real
4392         * allocation. But to not confuse with user, stat
4393         * will return the blocks that include the delayed allocation
4394         * blocks for this file.
4395         */
4396        delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
4397                                EXT4_I(inode)->i_reserved_data_blocks);
4398
4399        stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9;
4400        return 0;
4401}
4402
4403static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
4404{
4405        if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4406                return ext4_ind_trans_blocks(inode, nrblocks, chunk);
4407        return ext4_ext_index_trans_blocks(inode, nrblocks, chunk);
4408}
4409
4410/*
4411 * Account for index blocks, block groups bitmaps and block group
4412 * descriptor blocks if modify datablocks and index blocks
4413 * worse case, the indexs blocks spread over different block groups
4414 *
4415 * If datablocks are discontiguous, they are possible to spread over
4416 * different block groups too. If they are contiuguous, with flexbg,
4417 * they could still across block group boundary.
4418 *
4419 * Also account for superblock, inode, quota and xattr blocks
4420 */
4421static int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
4422{
4423        ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
4424        int gdpblocks;
4425        int idxblocks;
4426        int ret = 0;
4427
4428        /*
4429         * How many index blocks need to touch to modify nrblocks?
4430         * The "Chunk" flag indicating whether the nrblocks is
4431         * physically contiguous on disk
4432         *
4433         * For Direct IO and fallocate, they calls get_block to allocate
4434         * one single extent at a time, so they could set the "Chunk" flag
4435         */
4436        idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk);
4437
4438        ret = idxblocks;
4439
4440        /*
4441         * Now let's see how many group bitmaps and group descriptors need
4442         * to account
4443         */
4444        groups = idxblocks;
4445        if (chunk)
4446                groups += 1;
4447        else
4448                groups += nrblocks;
4449
4450        gdpblocks = groups;
4451        if (groups > ngroups)
4452                groups = ngroups;
4453        if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
4454                gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
4455
4456        /* bitmaps and block group descriptor blocks */
4457        ret += groups + gdpblocks;
4458
4459        /* Blocks for super block, inode, quota and xattr blocks */
4460        ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
4461
4462        return ret;
4463}
4464
4465/*
4466 * Calculate the total number of credits to reserve to fit
4467 * the modification of a single pages into a single transaction,
4468 * which may include multiple chunks of block allocations.
4469 *
4470 * This could be called via ext4_write_begin()
4471 *
4472 * We need to consider the worse case, when
4473 * one new block per extent.
4474 */
4475int ext4_writepage_trans_blocks(struct inode *inode)
4476{
4477        int bpp = ext4_journal_blocks_per_page(inode);
4478        int ret;
4479
4480        ret = ext4_meta_trans_blocks(inode, bpp, 0);
4481
4482        /* Account for data blocks for journalled mode */
4483        if (ext4_should_journal_data(inode))
4484                ret += bpp;
4485        return ret;
4486}
4487
4488/*
4489 * Calculate the journal credits for a chunk of data modification.
4490 *
4491 * This is called from DIO, fallocate or whoever calling
4492 * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
4493 *
4494 * journal buffers for data blocks are not included here, as DIO
4495 * and fallocate do no need to journal data buffers.
4496 */
4497int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
4498{
4499        return ext4_meta_trans_blocks(inode, nrblocks, 1);
4500}
4501
4502/*
4503 * The caller must have previously called ext4_reserve_inode_write().
4504 * Give this, we know that the caller already has write access to iloc->bh.
4505 */
4506int ext4_mark_iloc_dirty(handle_t *handle,
4507                         struct inode *inode, struct ext4_iloc *iloc)
4508{
4509        int err = 0;
4510
4511        if (IS_I_VERSION(inode))
4512                inode_inc_iversion(inode);
4513
4514        /* the do_update_inode consumes one bh->b_count */
4515        get_bh(iloc->bh);
4516
4517        /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
4518        err = ext4_do_update_inode(handle, inode, iloc);
4519        put_bh(iloc->bh);
4520        return err;
4521}
4522
4523/*
4524 * On success, We end up with an outstanding reference count against
4525 * iloc->bh.  This _must_ be cleaned up later.
4526 */
4527
4528int
4529ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
4530                         struct ext4_iloc *iloc)
4531{
4532        int err;
4533
4534        err = ext4_get_inode_loc(inode, iloc);
4535        if (!err) {
4536                BUFFER_TRACE(iloc->bh, "get_write_access");
4537                err = ext4_journal_get_write_access(handle, iloc->bh);
4538                if (err) {
4539                        brelse(iloc->bh);
4540                        iloc->bh = NULL;
4541                }
4542        }
4543        ext4_std_error(inode->i_sb, err);
4544        return err;
4545}
4546
4547/*
4548 * Expand an inode by new_extra_isize bytes.
4549 * Returns 0 on success or negative error number on failure.
4550 */
4551static int ext4_expand_extra_isize(struct inode *inode,
4552                                   unsigned int new_extra_isize,
4553                                   struct ext4_iloc iloc,
4554                                   handle_t *handle)
4555{
4556        struct ext4_inode *raw_inode;
4557        struct ext4_xattr_ibody_header *header;
4558
4559        if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
4560                return 0;
4561
4562        raw_inode = ext4_raw_inode(&iloc);
4563
4564        header = IHDR(inode, raw_inode);
4565
4566        /* No extended attributes present */
4567        if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
4568            header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
4569                memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
4570                        new_extra_isize);
4571                EXT4_I(inode)->i_extra_isize = new_extra_isize;
4572                return 0;
4573        }
4574
4575        /* try to expand with EAs present */
4576        return ext4_expand_extra_isize_ea(inode, new_extra_isize,
4577                                          raw_inode, handle);
4578}
4579
4580/*
4581 * What we do here is to mark the in-core inode as clean with respect to inode
4582 * dirtiness (it may still be data-dirty).
4583 * This means that the in-core inode may be reaped by prune_icache
4584 * without having to perform any I/O.  This is a very good thing,
4585 * because *any* task may call prune_icache - even ones which
4586 * have a transaction open against a different journal.
4587 *
4588 * Is this cheating?  Not really.  Sure, we haven't written the
4589 * inode out, but prune_icache isn't a user-visible syncing function.
4590 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
4591 * we start and wait on commits.
4592 */
4593int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
4594{
4595        struct ext4_iloc iloc;
4596        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4597        static unsigned int mnt_count;
4598        int err, ret;
4599
4600        might_sleep();
4601        trace_ext4_mark_inode_dirty(inode, _RET_IP_);
4602        err = ext4_reserve_inode_write(handle, inode, &iloc);
4603        if (ext4_handle_valid(handle) &&
4604            EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
4605            !ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
4606                /*
4607                 * We need extra buffer credits since we may write into EA block
4608                 * with this same handle. If journal_extend fails, then it will
4609                 * only result in a minor loss of functionality for that inode.
4610                 * If this is felt to be critical, then e2fsck should be run to
4611                 * force a large enough s_min_extra_isize.
4612                 */
4613                if ((jbd2_journal_extend(handle,
4614                             EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
4615                        ret = ext4_expand_extra_isize(inode,
4616                                                      sbi->s_want_extra_isize,
4617                                                      iloc, handle);
4618                        if (ret) {
4619                                ext4_set_inode_state(inode,
4620                                                     EXT4_STATE_NO_EXPAND);
4621                                if (mnt_count !=
4622                                        le16_to_cpu(sbi->s_es->s_mnt_count)) {
4623                                        ext4_warning(inode->i_sb,
4624                                        "Unable to expand inode %lu. Delete"
4625                                        " some EAs or run e2fsck.",
4626                                        inode->i_ino);
4627                                        mnt_count =
4628                                          le16_to_cpu(sbi->s_es->s_mnt_count);
4629                                }
4630                        }
4631                }
4632        }
4633        if (!err)
4634                err = ext4_mark_iloc_dirty(handle, inode, &iloc);
4635        return err;
4636}
4637
4638/*
4639 * ext4_dirty_inode() is called from __mark_inode_dirty()
4640 *
4641 * We're really interested in the case where a file is being extended.
4642 * i_size has been changed by generic_commit_write() and we thus need
4643 * to include the updated inode in the current transaction.
4644 *
4645 * Also, dquot_alloc_block() will always dirty the inode when blocks
4646 * are allocated to the file.
4647 *
4648 * If the inode is marked synchronous, we don't honour that here - doing
4649 * so would cause a commit on atime updates, which we don't bother doing.
4650 * We handle synchronous inodes at the highest possible level.
4651 */
4652void ext4_dirty_inode(struct inode *inode, int flags)
4653{
4654        handle_t *handle;
4655
4656        handle = ext4_journal_start(inode, 2);
4657        if (IS_ERR(handle))
4658                goto out;
4659
4660        ext4_mark_inode_dirty(handle, inode);
4661
4662        ext4_journal_stop(handle);
4663out:
4664        return;
4665}
4666
4667#if 0
4668/*
4669 * Bind an inode's backing buffer_head into this transaction, to prevent
4670 * it from being flushed to disk early.  Unlike
4671 * ext4_reserve_inode_write, this leaves behind no bh reference and
4672 * returns no iloc structure, so the caller needs to repeat the iloc
4673 * lookup to mark the inode dirty later.
4674 */
4675static int ext4_pin_inode(handle_t *handle, struct inode *inode)
4676{
4677        struct ext4_iloc iloc;
4678
4679        int err = 0;
4680        if (handle) {
4681                err = ext4_get_inode_loc(inode, &iloc);
4682                if (!err) {
4683                        BUFFER_TRACE(iloc.bh, "get_write_access");
4684                        err = jbd2_journal_get_write_access(handle, iloc.bh);
4685                        if (!err)
4686                                err = ext4_handle_dirty_metadata(handle,
4687                                                                 NULL,
4688                                                                 iloc.bh);
4689                        brelse(iloc.bh);
4690                }
4691        }
4692        ext4_std_error(inode->i_sb, err);
4693        return err;
4694}
4695#endif
4696
4697int ext4_change_inode_journal_flag(struct inode *inode, int val)
4698{
4699        journal_t *journal;
4700        handle_t *handle;
4701        int err;
4702
4703        /*
4704         * We have to be very careful here: changing a data block's
4705         * journaling status dynamically is dangerous.  If we write a
4706         * data block to the journal, change the status and then delete
4707         * that block, we risk forgetting to revoke the old log record
4708         * from the journal and so a subsequent replay can corrupt data.
4709         * So, first we make sure that the journal is empty and that
4710         * nobody is changing anything.
4711         */
4712
4713        journal = EXT4_JOURNAL(inode);
4714        if (!journal)
4715                return 0;
4716        if (is_journal_aborted(journal))
4717                return -EROFS;
4718        /* We have to allocate physical blocks for delalloc blocks
4719         * before flushing journal. otherwise delalloc blocks can not
4720         * be allocated any more. even more truncate on delalloc blocks
4721         * could trigger BUG by flushing delalloc blocks in journal.
4722         * There is no delalloc block in non-journal data mode.
4723         */
4724        if (val && test_opt(inode->i_sb, DELALLOC)) {
4725                err = ext4_alloc_da_blocks(inode);
4726                if (err < 0)
4727                        return err;
4728        }
4729
4730        jbd2_journal_lock_updates(journal);
4731
4732        /*
4733         * OK, there are no updates running now, and all cached data is
4734         * synced to disk.  We are now in a completely consistent state
4735         * which doesn't have anything in the journal, and we know that
4736         * no filesystem updates are running, so it is safe to modify
4737         * the inode's in-core data-journaling state flag now.
4738         */
4739
4740        if (val)
4741                ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
4742        else {
4743                jbd2_journal_flush(journal);
4744                ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
4745        }
4746        ext4_set_aops(inode);
4747
4748        jbd2_journal_unlock_updates(journal);
4749
4750        /* Finally we can mark the inode as dirty. */
4751
4752        handle = ext4_journal_start(inode, 1);
4753        if (IS_ERR(handle))
4754                return PTR_ERR(handle);
4755
4756        err = ext4_mark_inode_dirty(handle, inode);
4757        ext4_handle_sync(handle);
4758        ext4_journal_stop(handle);
4759        ext4_std_error(inode->i_sb, err);
4760
4761        return err;
4762}
4763
4764static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
4765{
4766        return !buffer_mapped(bh);
4767}
4768
4769int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
4770{
4771        struct page *page = vmf->page;
4772        loff_t size;
4773        unsigned long len;
4774        int ret;
4775        struct file *file = vma->vm_file;
4776        struct inode *inode = file->f_path.dentry->d_inode;
4777        struct address_space *mapping = inode->i_mapping;
4778        handle_t *handle;
4779        get_block_t *get_block;
4780        int retries = 0;
4781
4782        sb_start_pagefault(inode->i_sb);
4783        /* Delalloc case is easy... */
4784        if (test_opt(inode->i_sb, DELALLOC) &&
4785            !ext4_should_journal_data(inode) &&
4786            !ext4_nonda_switch(inode->i_sb)) {
4787                do {
4788                        ret = __block_page_mkwrite(vma, vmf,
4789                                                   ext4_da_get_block_prep);
4790                } while (ret == -ENOSPC &&
4791                       ext4_should_retry_alloc(inode->i_sb, &retries));
4792                goto out_ret;
4793        }
4794
4795        lock_page(page);
4796        size = i_size_read(inode);
4797        /* Page got truncated from under us? */
4798        if (page->mapping != mapping || page_offset(page) > size) {
4799                unlock_page(page);
4800                ret = VM_FAULT_NOPAGE;
4801                goto out;
4802        }
4803
4804        if (page->index == size >> PAGE_CACHE_SHIFT)
4805                len = size & ~PAGE_CACHE_MASK;
4806        else
4807                len = PAGE_CACHE_SIZE;
4808        /*
4809         * Return if we have all the buffers mapped. This avoids the need to do
4810         * journal_start/journal_stop which can block and take a long time
4811         */
4812        if (page_has_buffers(page)) {
4813                if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
4814                                        ext4_bh_unmapped)) {
4815                        /* Wait so that we don't change page under IO */
4816                        wait_on_page_writeback(page);
4817                        ret = VM_FAULT_LOCKED;
4818                        goto out;
4819                }
4820        }
4821        unlock_page(page);
4822        /* OK, we need to fill the hole... */
4823        if (ext4_should_dioread_nolock(inode))
4824                get_block = ext4_get_block_write;
4825        else
4826                get_block = ext4_get_block;
4827retry_alloc:
4828        handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
4829        if (IS_ERR(handle)) {
4830                ret = VM_FAULT_SIGBUS;
4831                goto out;
4832        }
4833        ret = __block_page_mkwrite(vma, vmf, get_block);
4834        if (!ret && ext4_should_journal_data(inode)) {
4835                if (walk_page_buffers(handle, page_buffers(page), 0,
4836                          PAGE_CACHE_SIZE, NULL, do_journal_get_write_access)) {
4837                        unlock_page(page);
4838                        ret = VM_FAULT_SIGBUS;
4839                        ext4_journal_stop(handle);
4840                        goto out;
4841                }
4842                ext4_set_inode_state(inode, EXT4_STATE_JDATA);
4843        }
4844        ext4_journal_stop(handle);
4845        if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
4846                goto retry_alloc;
4847out_ret:
4848        ret = block_page_mkwrite_return(ret);
4849out:
4850        sb_end_pagefault(inode->i_sb);
4851        return ret;
4852}
4853
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