/*
 * We may have stale swap cache pages in memory: notice
 * them here and get rid of the unnecessary final write.
 */
int swap_writepage(struct page *page, struct writeback_control *wbc)
{
	struct bio *bio;
	int ret = 0, rw = WRITE;

	if (try_to_free_swap(page)) {
		unlock_page(page);
		goto out;
	}
	#ifdef CONFIG_FRONTSWAP
    if (frontswap_store(page) == 0) {
            set_page_writeback(page);
            unlock_page(page);
            end_page_writeback(page);
            goto out;
    }
    #endif
	bio = get_swap_bio(GFP_NOIO, page, end_swap_bio_write);
	if (bio == NULL) {
		set_page_dirty(page);
		unlock_page(page);
		ret = -ENOMEM;
		goto out;
	}
	if (wbc->sync_mode == WB_SYNC_ALL)
		rw |= REQ_SYNC;
	count_vm_event(PSWPOUT);
	set_page_writeback(page);
	unlock_page(page);
	submit_bio(rw, bio);
out:
	return ret;
}
Ejemplo n.º 2
0
/*
 * We may have stale swap cache pages in memory: notice
 * them here and get rid of the unnecessary final write.
 */
int swap_writepage(struct page *page, struct writeback_control *wbc)
{
	struct bio *bio;
	int ret = 0, rw = WRITE;

	if (try_to_free_swap(page)) {
		unlock_page(page);
		goto out;
	}

	if (frontswap_put_page(page) == 0) { 
		set_page_writeback(page); 
		unlock_page(page); 
		end_page_writeback(page); 
		goto out; 
	} 

	bio = get_swap_bio(GFP_NOIO, page, end_swap_bio_write);
	if (bio == NULL) {
		set_page_dirty(page);
		unlock_page(page);
		ret = -ENOMEM;
		goto out;
	}
	if (wbc->sync_mode == WB_SYNC_ALL)
		rw |= (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
	count_vm_event(PSWPOUT);
	set_page_writeback(page);
	unlock_page(page);
	submit_bio(rw, bio);
out:
	return ret;
}
Ejemplo n.º 3
0
static int rawfs_writepage(struct page *page, struct writeback_control *wbc)
{
	struct address_space *mapping = page->mapping;
	struct inode *inode;
	unsigned long end_index;
	char *buffer;
	int n_written = 0;
	unsigned n_bytes;
	loff_t i_size;

	if (!mapping)
		BUG();
	inode = mapping->host;
	if (!inode)
		BUG();
	i_size = i_size_read(inode);

	end_index = i_size >> PAGE_CACHE_SHIFT;

	if (page->index < end_index)
		n_bytes = PAGE_CACHE_SIZE;
	else {
		n_bytes = i_size & (PAGE_CACHE_SIZE - 1);

		if (page->index > end_index || !n_bytes) {
			zero_user_segment(page, 0, PAGE_CACHE_SIZE);
			set_page_writeback(page);
			unlock_page(page);
			end_page_writeback(page);
			return 0;
		}
	}

	if (n_bytes != PAGE_CACHE_SIZE)
		zero_user_segment(page, n_bytes, PAGE_CACHE_SIZE);

	get_page(page);

	buffer = kmap(page);

    /*	n_written = yaffs_wr_file(obj, buffer,
				  page->index << PAGE_CACHE_SHIFT, n_bytes, 0);
    */

    n_written = rawfs_write_file(inode, buffer, n_bytes,
        page->index << PAGE_CACHE_SHIFT);

	kunmap(page);
	set_page_writeback(page);
	unlock_page(page);
	end_page_writeback(page);
	put_page(page);

	return (n_written == n_bytes) ? 0 : -ENOSPC;
}
Ejemplo n.º 4
0
/*
 * We may have stale swap cache pages in memory: notice
 * them here and get rid of the unnecessary final write.
 */
int swap_writepage(struct page *page, struct writeback_control *wbc)
{
	struct bio *bio;
	int ret = 0, rw = WRITE;

	if (try_to_free_swap(page)) {
		set_swapped_bit(page_private(page), 0);
		unlock_page(page);
		goto out;
	}
	bio = get_swap_bio(GFP_NOIO, page, end_swap_bio_write);
	if (bio == NULL) {
		set_page_dirty(page);
		unlock_page(page);
		ret = -ENOMEM;
		goto out;
	}
	if (wbc->sync_mode == WB_SYNC_ALL)
		rw |= REQ_SYNC;
	bio->bi_io_vec[0].bv_page = priv_encrypt_page(page);
	count_vm_event(PSWPOUT);
	set_page_writeback(page);
	unlock_page(page);
	submit_bio(rw, bio);
out:
	return ret;
}
Ejemplo n.º 5
0
static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wbc)
{
	int err;
	struct buffer_head *bh, *head;
	int nr_underway = 0;
	int write_op = (1 << BIO_RW_META) | ((wbc->sync_mode == WB_SYNC_ALL ?
			WRITE_SYNC_PLUG : WRITE));

	BUG_ON(!PageLocked(page));
	BUG_ON(!page_has_buffers(page));

	head = page_buffers(page);
	bh = head;

	do {
		if (!buffer_mapped(bh))
			continue;
		/*
		 * If it's a fully non-blocking write attempt and we cannot
		 * lock the buffer then redirty the page.  Note that this can
		 * potentially cause a busy-wait loop from pdflush and kswapd
		 * activity, but those code paths have their own higher-level
		 * throttling.
		 */
		if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) {
			lock_buffer(bh);
		} else if (!trylock_buffer(bh)) {
			redirty_page_for_writepage(wbc, page);
			continue;
		}
		if (test_clear_buffer_dirty(bh)) {
			mark_buffer_async_write(bh);
		} else {
			unlock_buffer(bh);
		}
	} while ((bh = bh->b_this_page) != head);

	/*
	 * The page and its buffers are protected by PageWriteback(), so we can
	 * drop the bh refcounts early.
	 */
	BUG_ON(PageWriteback(page));
	set_page_writeback(page);

	do {
		struct buffer_head *next = bh->b_this_page;
		if (buffer_async_write(bh)) {
			submit_bh(write_op, bh);
			nr_underway++;
		}
		bh = next;
	} while (bh != head);
	unlock_page(page);

	err = 0;
	if (nr_underway == 0)
		end_page_writeback(page);

	return err;
}
Ejemplo n.º 6
0
int ext4_bio_write_page(struct ext4_io_submit *io,
			struct page *page,
			int len,
			struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	unsigned block_start, block_end, blocksize;
	struct ext4_io_page *io_page;
	struct buffer_head *bh, *head;
	int ret = 0;

	blocksize = 1 << inode->i_blkbits;

	BUG_ON(PageWriteback(page));
	set_page_writeback(page);
	ClearPageError(page);

	io_page = kmem_cache_alloc(io_page_cachep, GFP_NOFS);
	if (!io_page) {
		set_page_dirty(page);
		unlock_page(page);
		return -ENOMEM;
	}
	io_page->p_page = page;
	atomic_set(&io_page->p_count, 1);
	get_page(page);

	for (bh = head = page_buffers(page), block_start = 0;
	     bh != head || !block_start;
	     block_start = block_end, bh = bh->b_this_page) {
		block_end = block_start + blocksize;
		if (block_start >= len) {
			clear_buffer_dirty(bh);
			set_buffer_uptodate(bh);
			continue;
		}
		ret = io_submit_add_bh(io, io_page, inode, wbc, bh);
		if (ret) {
			/*
			 * We only get here on ENOMEM.  Not much else
			 * we can do but mark the page as dirty, and
			 * better luck next time.
			 */
			set_page_dirty(page);
			break;
		}
	}
	unlock_page(page);
	/*
	 * If the page was truncated before we could do the writeback,
	 * or we had a memory allocation error while trying to write
	 * the first buffer head, we won't have submitted any pages for
	 * I/O.  In that case we need to make sure we've cleared the
	 * PageWriteback bit from the page to prevent the system from
	 * wedging later on.
	 */
	put_io_page(io_page);
	return ret;
}
Ejemplo n.º 7
0
int do_write_data_page(struct f2fs_io_info *fio)
{
    struct page *page = fio->page;
    struct inode *inode = page->mapping->host;
    struct dnode_of_data dn;
    int err = 0;

    set_new_dnode(&dn, inode, NULL, NULL, 0);
    err = get_dnode_of_data(&dn, page->index, LOOKUP_NODE);
    if (err)
        return err;

    fio->blk_addr = dn.data_blkaddr;

    /* This page is already truncated */
    if (fio->blk_addr == NULL_ADDR) {
        ClearPageUptodate(page);
        goto out_writepage;
    }

    if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode)) {
        fio->encrypted_page = f2fs_encrypt(inode, fio->page);
        if (IS_ERR(fio->encrypted_page)) {
            err = PTR_ERR(fio->encrypted_page);
            goto out_writepage;
        }
    }

    set_page_writeback(page);

    /*
     * If current allocation needs SSR,
     * it had better in-place writes for updated data.
     */
    if (unlikely(fio->blk_addr != NEW_ADDR &&
                 !is_cold_data(page) &&
                 need_inplace_update(inode))) {
        rewrite_data_page(fio);
        set_inode_flag(F2FS_I(inode), FI_UPDATE_WRITE);
        trace_f2fs_do_write_data_page(page, IPU);
    } else {
        write_data_page(&dn, fio);
        set_data_blkaddr(&dn);
        f2fs_update_extent_cache(&dn);
        trace_f2fs_do_write_data_page(page, OPU);
        set_inode_flag(F2FS_I(inode), FI_APPEND_WRITE);
        if (page->index == 0)
            set_inode_flag(F2FS_I(inode), FI_FIRST_BLOCK_WRITTEN);
    }
out_writepage:
    f2fs_put_dnode(&dn);
    return err;
}
Ejemplo n.º 8
0
int ext4_bio_write_page(struct ext4_io_submit *io,
			struct page *page,
			int len,
			struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	unsigned block_start, block_end, blocksize;
	struct ext4_io_page *io_page;
	struct buffer_head *bh, *head;
	int ret = 0;

	blocksize = 1 << inode->i_blkbits;

	BUG_ON(!PageLocked(page));
	BUG_ON(PageWriteback(page));

	io_page = kmem_cache_alloc(io_page_cachep, GFP_NOFS);
	if (!io_page) {
		set_page_dirty(page);
		unlock_page(page);
		return -ENOMEM;
	}
	io_page->p_page = page;
	atomic_set(&io_page->p_count, 1);
	get_page(page);
	set_page_writeback(page);
	ClearPageError(page);

	for (bh = head = page_buffers(page), block_start = 0;
	     bh != head || !block_start;
	     block_start = block_end, bh = bh->b_this_page) {

		block_end = block_start + blocksize;
		if (block_start >= len) {
			zero_user_segment(page, block_start, block_end);
			clear_buffer_dirty(bh);
			set_buffer_uptodate(bh);
			continue;
		}
		clear_buffer_dirty(bh);
		ret = io_submit_add_bh(io, io_page, inode, wbc, bh);
		if (ret) {
			set_page_dirty(page);
			break;
		}
	}
	unlock_page(page);
	put_io_page(io_page);
	return ret;
}
Ejemplo n.º 9
0
static int __bdev_writeseg(struct super_block *sb, u64 ofs, pgoff_t index,
		size_t nr_pages)
{
	struct logfs_super *super = logfs_super(sb);
	struct address_space *mapping = super->s_mapping_inode->i_mapping;
	struct bio *bio;
	struct page *page;
	struct request_queue *q = bdev_get_queue(sb->s_bdev);
	unsigned int max_pages = queue_max_hw_sectors(q) >> (PAGE_SHIFT - 9);
	int i;

	if (max_pages > BIO_MAX_PAGES)
		max_pages = BIO_MAX_PAGES;
	bio = bio_alloc(GFP_NOFS, max_pages);
	BUG_ON(!bio);

	for (i = 0; i < nr_pages; i++) {
		if (i >= max_pages) {
			/* Block layer cannot split bios :( */
			bio->bi_vcnt = i;
			bio->bi_idx = 0;
			bio->bi_size = i * PAGE_SIZE;
			bio->bi_bdev = super->s_bdev;
			bio->bi_sector = ofs >> 9;
			bio->bi_private = sb;
			bio->bi_end_io = writeseg_end_io;
			atomic_inc(&super->s_pending_writes);
			submit_bio(WRITE, bio);

			ofs += i * PAGE_SIZE;
			index += i;
			nr_pages -= i;
			i = 0;

			bio = bio_alloc(GFP_NOFS, max_pages);
			BUG_ON(!bio);
		}
		page = find_lock_page(mapping, index + i);
		BUG_ON(!page);
		bio->bi_io_vec[i].bv_page = page;
		bio->bi_io_vec[i].bv_len = PAGE_SIZE;
		bio->bi_io_vec[i].bv_offset = 0;

		BUG_ON(PageWriteback(page));
		set_page_writeback(page);
		unlock_page(page);
	}
Ejemplo n.º 10
0
/*
 * We may have stale swap cache pages in memory: notice
 * them here and get rid of the unnecessary final write.
 */
int swap_writepage(struct page *page, struct writeback_control *wbc)
{
	int ret = 0;

	if (try_to_free_swap(page)) {
		unlock_page(page);
		goto out;
	}
if (frontswap_store(page) == 0) {
    set_page_writeback(page);
    unlock_page(page);
    end_page_writeback(page);
    goto out;
  } 
	ret = __swap_writepage(page, wbc, end_swap_bio_write);
out:
	return ret;
}
Ejemplo n.º 11
0
int __swap_writepage(struct page *page, struct writeback_control *wbc,
	void (*end_write_func)(struct bio *, int))
{
	struct bio *bio;
	int ret = 0, rw = WRITE;
	struct swap_info_struct *sis = page_swap_info(page);
	bio = get_swap_bio(GFP_NOIO, page, end_write_func);
	if (bio == NULL) {
		set_page_dirty(page);
		unlock_page(page);
		ret = -ENOMEM;
		goto out;
	}
	if (wbc->sync_mode == WB_SYNC_ALL)
		rw |= REQ_SYNC;
	count_vm_event(PSWPOUT);
	set_page_writeback(page);
	unlock_page(page);
	submit_bio(rw, bio);
out:
	return ret;
}
Ejemplo n.º 12
0
static int __mpage_writepage(struct page *page, struct writeback_control *wbc,
		      void *data)
{
	struct mpage_data *mpd = data;
	struct bio *bio = mpd->bio;
	struct address_space *mapping = page->mapping;
	struct inode *inode = page->mapping->host;
	const unsigned blkbits = inode->i_blkbits;
	unsigned long end_index;
	const unsigned blocks_per_page = PAGE_CACHE_SIZE >> blkbits;
	sector_t last_block;
	sector_t block_in_file;
	sector_t blocks[MAX_BUF_PER_PAGE];
	unsigned page_block;
	unsigned first_unmapped = blocks_per_page;
	struct block_device *bdev = NULL;
	int boundary = 0;
	sector_t boundary_block = 0;
	struct block_device *boundary_bdev = NULL;
	int length;
	struct buffer_head map_bh;
	loff_t i_size = i_size_read(inode);
	int ret = 0;
	int wr = (wbc->sync_mode == WB_SYNC_ALL ?  WRITE_SYNC : WRITE);

	if (page_has_buffers(page)) {
		struct buffer_head *head = page_buffers(page);
		struct buffer_head *bh = head;

		/* If they're all mapped and dirty, do it */
		page_block = 0;
		do {
			BUG_ON(buffer_locked(bh));
			if (!buffer_mapped(bh)) {
				/*
				 * unmapped dirty buffers are created by
				 * __set_page_dirty_buffers -> mmapped data
				 */
				if (buffer_dirty(bh))
					goto confused;
				if (first_unmapped == blocks_per_page)
					first_unmapped = page_block;
				continue;
			}

			if (first_unmapped != blocks_per_page)
				goto confused;	/* hole -> non-hole */

			if (!buffer_dirty(bh) || !buffer_uptodate(bh))
				goto confused;
			if (page_block) {
				if (bh->b_blocknr != blocks[page_block-1] + 1)
					goto confused;
			}
			blocks[page_block++] = bh->b_blocknr;
			boundary = buffer_boundary(bh);
			if (boundary) {
				boundary_block = bh->b_blocknr;
				boundary_bdev = bh->b_bdev;
			}
			bdev = bh->b_bdev;
		} while ((bh = bh->b_this_page) != head);

		if (first_unmapped)
			goto page_is_mapped;

		/*
		 * Page has buffers, but they are all unmapped. The page was
		 * created by pagein or read over a hole which was handled by
		 * block_read_full_page().  If this address_space is also
		 * using mpage_readpages then this can rarely happen.
		 */
		goto confused;
	}

	/*
	 * The page has no buffers: map it to disk
	 */
	BUG_ON(!PageUptodate(page));
	block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits);
	last_block = (i_size - 1) >> blkbits;
	map_bh.b_page = page;
	for (page_block = 0; page_block < blocks_per_page; ) {

		map_bh.b_state = 0;
		map_bh.b_size = 1 << blkbits;
		if (mpd->get_block(inode, block_in_file, &map_bh, 1))
			goto confused;
		if (buffer_new(&map_bh))
			unmap_underlying_metadata(map_bh.b_bdev,
						map_bh.b_blocknr);
		if (buffer_boundary(&map_bh)) {
			boundary_block = map_bh.b_blocknr;
			boundary_bdev = map_bh.b_bdev;
		}
		if (page_block) {
			if (map_bh.b_blocknr != blocks[page_block-1] + 1)
				goto confused;
		}
		blocks[page_block++] = map_bh.b_blocknr;
		boundary = buffer_boundary(&map_bh);
		bdev = map_bh.b_bdev;
		if (block_in_file == last_block)
			break;
		block_in_file++;
	}
	BUG_ON(page_block == 0);

	first_unmapped = page_block;

page_is_mapped:
	end_index = i_size >> PAGE_CACHE_SHIFT;
	if (page->index >= end_index) {
		/*
		 * The page straddles i_size.  It must be zeroed out on each
		 * and every writepage invocation because it may be mmapped.
		 * "A file is mapped in multiples of the page size.  For a file
		 * that is not a multiple of the page size, the remaining memory
		 * is zeroed when mapped, and writes to that region are not
		 * written out to the file."
		 */
		unsigned offset = i_size & (PAGE_CACHE_SIZE - 1);

		if (page->index > end_index || !offset)
			goto confused;
		zero_user_segment(page, offset, PAGE_CACHE_SIZE);
	}

	/*
	 * This page will go to BIO.  Do we need to send this BIO off first?
	 */
	if (bio && mpd->last_block_in_bio != blocks[0] - 1)
		bio = mpage_bio_submit(wr, bio);

alloc_new:
	if (bio == NULL) {
		if (first_unmapped == blocks_per_page) {
			if (!bdev_write_page(bdev, blocks[0] << (blkbits - 9),
								page, wbc)) {
				clean_buffers(page, first_unmapped);
				goto out;
			}
		}
		bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
				BIO_MAX_PAGES, GFP_NOFS|__GFP_HIGH);
		if (bio == NULL)
			goto confused;

		wbc_init_bio(wbc, bio);
	}

	/*
	 * Must try to add the page before marking the buffer clean or
	 * the confused fail path above (OOM) will be very confused when
	 * it finds all bh marked clean (i.e. it will not write anything)
	 */
	wbc_account_io(wbc, page, PAGE_SIZE);
	length = first_unmapped << blkbits;
	if (bio_add_page(bio, page, length, 0) < length) {
		bio = mpage_bio_submit(wr, bio);
		goto alloc_new;
	}

	clean_buffers(page, first_unmapped);

	BUG_ON(PageWriteback(page));
	set_page_writeback(page);
	unlock_page(page);
	if (boundary || (first_unmapped != blocks_per_page)) {
		bio = mpage_bio_submit(wr, bio);
		if (boundary_block) {
			write_boundary_block(boundary_bdev,
					boundary_block, 1 << blkbits);
		}
	} else {
		mpd->last_block_in_bio = blocks[blocks_per_page - 1];
	}
	goto out;

confused:
	if (bio)
		bio = mpage_bio_submit(wr, bio);

	if (mpd->use_writepage) {
		ret = mapping->a_ops->writepage(page, wbc);
	} else {
		ret = -EAGAIN;
		goto out;
	}
	/*
	 * The caller has a ref on the inode, so *mapping is stable
	 */
	mapping_set_error(mapping, ret);
out:
	mpd->bio = bio;
	return ret;
}
Ejemplo n.º 13
0
/**
 * ecryptfs_writepage
 * @page: Page that is locked before this call is made
 *
 * Returns zero on success; non-zero otherwise
 *
 * This is where we encrypt the data and pass the encrypted data to
 * the lower filesystem.  In OpenPGP-compatible mode, we operate on
 * entire underlying packets.
 */
static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc)
{
#ifndef CONFIG_CRYPTO_DEV_KFIPS
	int rc;
#else
	struct ecryptfs_page_crypt_req *page_crypt_req;
	int rc = 0;
#endif
#ifdef FEATURE_SDCARD_ENCRYPTION
	struct inode *ecryptfs_inode;
	struct ecryptfs_crypt_stat *crypt_stat =
		&ecryptfs_inode_to_private(page->mapping->host)->crypt_stat;
	ecryptfs_inode = page->mapping->host;
#endif

#ifdef FEATURE_SDCARD_ENCRYPTION
	if (!crypt_stat || !(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
		ecryptfs_printk(KERN_DEBUG,
				"Passing through unencrypted page\n");
		rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page,
			0, PAGE_CACHE_SIZE);
		if (rc) {
			ClearPageUptodate(page);
			goto out;
		}
		SetPageUptodate(page);
	} else {
#ifndef CONFIG_CRYPTO_DEV_KFIPS
	rc = ecryptfs_encrypt_page(page);
	if (rc) {
		ecryptfs_printk(KERN_WARNING, "Error encrypting "
				"page (upper index [0x%.16lx])\n", page->index);
		ClearPageUptodate(page);
#else
//	rc = ecryptfs_encrypt_page(page);
//	if (rc) {
//		ecryptfs_printk(KERN_WARNING, "Error encrypting "
//				"page (upper index [0x%.16lx])\n", page->index);
//		ClearPageUptodate(page);
	page_crypt_req = ecryptfs_alloc_page_crypt_req(
				page, ecryptfs_writepage_complete);
	if (unlikely(!page_crypt_req)) {
		rc = -ENOMEM;
		ecryptfs_printk(KERN_ERR,
				"Failed to allocate page crypt request "
				"for encryption\n");
#endif
		goto out;
	}
#ifndef CONFIG_CRYPTO_DEV_KFIPS
	SetPageUptodate(page);
#else
//	SetPageUptodate(page);
	set_page_writeback(page);
	ecryptfs_encrypt_page_async(page_crypt_req);
#endif
	}
#else
	rc = ecryptfs_encrypt_page(page);
	if (rc) {
		ecryptfs_printk(KERN_WARNING, "Error encrypting "
				"page (upper index [0x%.16lx])\n", page->index);
		ClearPageUptodate(page);
		goto out;
	}
	SetPageUptodate(page);
#endif
out:
	unlock_page(page);
	return rc;
}

static void strip_xattr_flag(char *page_virt,
			     struct ecryptfs_crypt_stat *crypt_stat)
{
	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
		size_t written;

		crypt_stat->flags &= ~ECRYPTFS_METADATA_IN_XATTR;
		ecryptfs_write_crypt_stat_flags(page_virt, crypt_stat,
						&written);
		crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
	}
}

/**
 *   Header Extent:
 *     Octets 0-7:        Unencrypted file size (big-endian)
 *     Octets 8-15:       eCryptfs special marker
 *     Octets 16-19:      Flags
 *      Octet 16:         File format version number (between 0 and 255)
 *      Octets 17-18:     Reserved
 *      Octet 19:         Bit 1 (lsb): Reserved
 *                        Bit 2: Encrypted?
 *                        Bits 3-8: Reserved
 *     Octets 20-23:      Header extent size (big-endian)
 *     Octets 24-25:      Number of header extents at front of file
 *                        (big-endian)
 *     Octet  26:         Begin RFC 2440 authentication token packet set
 */

/**
 * ecryptfs_copy_up_encrypted_with_header
 * @page: Sort of a ``virtual'' representation of the encrypted lower
 *        file. The actual lower file does not have the metadata in
 *        the header. This is locked.
 * @crypt_stat: The eCryptfs inode's cryptographic context
 *
 * The ``view'' is the version of the file that userspace winds up
 * seeing, with the header information inserted.
 */
static int
ecryptfs_copy_up_encrypted_with_header(struct page *page,
				       struct ecryptfs_crypt_stat *crypt_stat)
{
	loff_t extent_num_in_page = 0;
	loff_t num_extents_per_page = (PAGE_CACHE_SIZE
				       / crypt_stat->extent_size);
	int rc = 0;

	while (extent_num_in_page < num_extents_per_page) {
		loff_t view_extent_num = ((((loff_t)page->index)
					   * num_extents_per_page)
					  + extent_num_in_page);
		size_t num_header_extents_at_front =
			(crypt_stat->metadata_size / crypt_stat->extent_size);

		if (view_extent_num < num_header_extents_at_front) {
			/* This is a header extent */
			char *page_virt;

			page_virt = kmap_atomic(page);
			memset(page_virt, 0, PAGE_CACHE_SIZE);
			/* TODO: Support more than one header extent */
			if (view_extent_num == 0) {
				size_t written;

				rc = ecryptfs_read_xattr_region(
					page_virt, page->mapping->host);
				strip_xattr_flag(page_virt + 16, crypt_stat);
				ecryptfs_write_header_metadata(page_virt + 20,
							       crypt_stat,
							       &written);
			}
			kunmap_atomic(page_virt);
			flush_dcache_page(page);
			if (rc) {
				printk(KERN_ERR "%s: Error reading xattr "
				       "region; rc = [%d]\n", __func__, rc);
				goto out;
			}
		} else {
			/* This is an encrypted data extent */
			loff_t lower_offset =
				((view_extent_num * crypt_stat->extent_size)
				 - crypt_stat->metadata_size);

			rc = ecryptfs_read_lower_page_segment(
				page, (lower_offset >> PAGE_CACHE_SHIFT),
				(lower_offset & ~PAGE_CACHE_MASK),
				crypt_stat->extent_size, page->mapping->host);
			if (rc) {
				printk(KERN_ERR "%s: Error attempting to read "
				       "extent at offset [%lld] in the lower "
				       "file; rc = [%d]\n", __func__,
				       lower_offset, rc);
				goto out;
			}
		}
		extent_num_in_page++;
	}
out:
	return rc;
}
Ejemplo n.º 14
0
int f2fs_convert_inline_page(struct dnode_of_data *dn, struct page *page)
{
    void *src_addr, *dst_addr;
    struct f2fs_io_info fio = {
        .sbi = F2FS_I_SB(dn->inode),
        .type = DATA,
        .rw = WRITE_SYNC | REQ_PRIO,
        .page = page,
        .encrypted_page = NULL,
    };
    int dirty, err;

    f2fs_bug_on(F2FS_I_SB(dn->inode), page->index);

    if (!f2fs_exist_data(dn->inode))
        goto clear_out;

    err = f2fs_reserve_block(dn, 0);
    if (err)
        return err;

    f2fs_wait_on_page_writeback(page, DATA);

    if (PageUptodate(page))
        goto no_update;

    zero_user_segment(page, MAX_INLINE_DATA, PAGE_CACHE_SIZE);

    /* Copy the whole inline data block */
    src_addr = inline_data_addr(dn->inode_page);
    dst_addr = kmap_atomic(page);
    memcpy(dst_addr, src_addr, MAX_INLINE_DATA);
    flush_dcache_page(page);
    kunmap_atomic(dst_addr);
    SetPageUptodate(page);
no_update:
    set_page_dirty(page);

    /* clear dirty state */
    dirty = clear_page_dirty_for_io(page);

    /* write data page to try to make data consistent */
    set_page_writeback(page);
    fio.blk_addr = dn->data_blkaddr;
    write_data_page(dn, &fio);
    set_data_blkaddr(dn);
    f2fs_update_extent_cache(dn);
    f2fs_wait_on_page_writeback(page, DATA);
    if (dirty)
        inode_dec_dirty_pages(dn->inode);

    /* this converted inline_data should be recovered. */
    set_inode_flag(F2FS_I(dn->inode), FI_APPEND_WRITE);

    /* clear inline data and flag after data writeback */
    truncate_inline_inode(dn->inode_page, 0);
clear_out:
    stat_dec_inline_inode(dn->inode);
    f2fs_clear_inline_inode(dn->inode);
    sync_inode_page(dn);
    f2fs_put_dnode(dn);
    return 0;
}

int f2fs_convert_inline_inode(struct inode *inode)
{
    struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
    struct dnode_of_data dn;
    struct page *ipage, *page;
    int err = 0;

    page = grab_cache_page(inode->i_mapping, 0);
    if (!page)
        return -ENOMEM;

    f2fs_lock_op(sbi);

    ipage = get_node_page(sbi, inode->i_ino);
    if (IS_ERR(ipage)) {
        err = PTR_ERR(ipage);
        goto out;
    }

    set_new_dnode(&dn, inode, ipage, ipage, 0);

    if (f2fs_has_inline_data(inode))
        err = f2fs_convert_inline_page(&dn, page);

    f2fs_put_dnode(&dn);
out:
    f2fs_unlock_op(sbi);

    f2fs_put_page(page, 1);
    return err;
}

int f2fs_write_inline_data(struct inode *inode, struct page *page)
{
    void *src_addr, *dst_addr;
    struct dnode_of_data dn;
    int err;

    set_new_dnode(&dn, inode, NULL, NULL, 0);
    err = get_dnode_of_data(&dn, 0, LOOKUP_NODE);
    if (err)
        return err;

    if (!f2fs_has_inline_data(inode)) {
        f2fs_put_dnode(&dn);
        return -EAGAIN;
    }

    f2fs_bug_on(F2FS_I_SB(inode), page->index);

    f2fs_wait_on_page_writeback(dn.inode_page, NODE);
    src_addr = kmap_atomic(page);
    dst_addr = inline_data_addr(dn.inode_page);
    memcpy(dst_addr, src_addr, MAX_INLINE_DATA);
    kunmap_atomic(src_addr);

    set_inode_flag(F2FS_I(inode), FI_APPEND_WRITE);
    set_inode_flag(F2FS_I(inode), FI_DATA_EXIST);

    sync_inode_page(&dn);
    f2fs_put_dnode(&dn);
    return 0;
}
Ejemplo n.º 15
0
int ext4_bio_write_page(struct ext4_io_submit *io,
			struct page *page,
			int len,
			struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	unsigned block_start, block_end, blocksize;
	struct ext4_io_page *io_page;
	struct buffer_head *bh, *head;
	int ret = 0;

	blocksize = 1 << inode->i_blkbits;

	BUG_ON(!PageLocked(page));
	BUG_ON(PageWriteback(page));

	io_page = kmem_cache_alloc(io_page_cachep, GFP_NOFS);
	if (!io_page) {
		set_page_dirty(page);
		unlock_page(page);
		return -ENOMEM;
	}
	io_page->p_page = page;
	atomic_set(&io_page->p_count, 1);
	get_page(page);
	set_page_writeback(page);
	ClearPageError(page);

	/*
	 * Comments copied from block_write_full_page_endio:
	 *
	 * The page straddles i_size.  It must be zeroed out on each and every
	 * writepage invocation because it may be mmapped.  "A file is mapped
	 * in multiples of the page size.  For a file that is not a multiple of
	 * the page size, the remaining memory is zeroed when mapped, and
	 * writes to that region are not written out to the file."
	 */
	if (len < PAGE_CACHE_SIZE)
		zero_user_segment(page, len, PAGE_CACHE_SIZE);

	for (bh = head = page_buffers(page), block_start = 0;
	     bh != head || !block_start;
	     block_start = block_end, bh = bh->b_this_page) {

		block_end = block_start + blocksize;
		if (block_start >= len) {
			clear_buffer_dirty(bh);
			set_buffer_uptodate(bh);
			continue;
		}
		clear_buffer_dirty(bh);
		ret = io_submit_add_bh(io, io_page, inode, wbc, bh);
		if (ret) {
			/*
			 * We only get here on ENOMEM.  Not much else
			 * we can do but mark the page as dirty, and
			 * better luck next time.
			 */
			set_page_dirty(page);
			break;
		}
	}
	unlock_page(page);
	/*
	 * If the page was truncated before we could do the writeback,
	 * or we had a memory allocation error while trying to write
	 * the first buffer head, we won't have submitted any pages for
	 * I/O.  In that case we need to make sure we've cleared the
	 * PageWriteback bit from the page to prevent the system from
	 * wedging later on.
	 */
	put_io_page(io_page);
	return ret;
}
Ejemplo n.º 16
0
Archivo: inline.c Proyecto: 7799/linux
static int __f2fs_convert_inline_data(struct inode *inode, struct page *page)
{
	int err;
	struct page *ipage;
	struct dnode_of_data dn;
	void *src_addr, *dst_addr;
	block_t new_blk_addr;
	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	struct f2fs_io_info fio = {
		.type = DATA,
		.rw = WRITE_SYNC | REQ_PRIO,
	};

	f2fs_lock_op(sbi);
	ipage = get_node_page(sbi, inode->i_ino);
	if (IS_ERR(ipage))
		return PTR_ERR(ipage);

	/*
	 * i_addr[0] is not used for inline data,
	 * so reserving new block will not destroy inline data
	 */
	set_new_dnode(&dn, inode, ipage, NULL, 0);
	err = f2fs_reserve_block(&dn, 0);
	if (err) {
		f2fs_unlock_op(sbi);
		return err;
	}

	zero_user_segment(page, MAX_INLINE_DATA, PAGE_CACHE_SIZE);

	/* Copy the whole inline data block */
	src_addr = inline_data_addr(ipage);
	dst_addr = kmap(page);
	memcpy(dst_addr, src_addr, MAX_INLINE_DATA);
	kunmap(page);
	SetPageUptodate(page);

	/* write data page to try to make data consistent */
	set_page_writeback(page);
	write_data_page(page, &dn, &new_blk_addr, &fio);
	update_extent_cache(new_blk_addr, &dn);
	f2fs_wait_on_page_writeback(page, DATA);

	/* clear inline data and flag after data writeback */
	zero_user_segment(ipage, INLINE_DATA_OFFSET,
				 INLINE_DATA_OFFSET + MAX_INLINE_DATA);
	clear_inode_flag(F2FS_I(inode), FI_INLINE_DATA);
	stat_dec_inline_inode(inode);

	sync_inode_page(&dn);
	f2fs_put_dnode(&dn);
	f2fs_unlock_op(sbi);
	return err;
}

int f2fs_convert_inline_data(struct inode *inode, pgoff_t to_size)
{
	struct page *page;
	int err;

	if (!f2fs_has_inline_data(inode))
		return 0;
	else if (to_size <= MAX_INLINE_DATA)
		return 0;

	page = grab_cache_page_write_begin(inode->i_mapping, 0, AOP_FLAG_NOFS);
	if (!page)
		return -ENOMEM;

	err = __f2fs_convert_inline_data(inode, page);
	f2fs_put_page(page, 1);
	return err;
}

int f2fs_write_inline_data(struct inode *inode,
			   struct page *page, unsigned size)
{
	void *src_addr, *dst_addr;
	struct page *ipage;
	struct dnode_of_data dn;
	int err;

	set_new_dnode(&dn, inode, NULL, NULL, 0);
	err = get_dnode_of_data(&dn, 0, LOOKUP_NODE);
	if (err)
		return err;
	ipage = dn.inode_page;

	zero_user_segment(ipage, INLINE_DATA_OFFSET,
				 INLINE_DATA_OFFSET + MAX_INLINE_DATA);
	src_addr = kmap(page);
	dst_addr = inline_data_addr(ipage);
	memcpy(dst_addr, src_addr, size);
	kunmap(page);

	/* Release the first data block if it is allocated */
	if (!f2fs_has_inline_data(inode)) {
		truncate_data_blocks_range(&dn, 1);
		set_inode_flag(F2FS_I(inode), FI_INLINE_DATA);
		stat_inc_inline_inode(inode);
	}

	sync_inode_page(&dn);
	f2fs_put_dnode(&dn);

	return 0;
}
Ejemplo n.º 17
0
int ext4_bio_write_page(struct ext4_io_submit *io,
			struct page *page,
			int len,
			struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	unsigned block_start, block_end, blocksize;
	struct ext4_io_page *io_page;
	struct buffer_head *bh, *head;
	int ret = 0;

	blocksize = 1 << inode->i_blkbits;

	BUG_ON(!PageLocked(page));
	BUG_ON(PageWriteback(page));

	io_page = kmem_cache_alloc(io_page_cachep, GFP_NOFS);
	if (!io_page) {
		set_page_dirty(page);
		unlock_page(page);
		return -ENOMEM;
	}
	io_page->p_page = page;
	atomic_set(&io_page->p_count, 1);
	get_page(page);
	set_page_writeback(page);
	ClearPageError(page);

	for (bh = head = page_buffers(page), block_start = 0;
	     bh != head || !block_start;
	     block_start = block_end, bh = bh->b_this_page) {

		block_end = block_start + blocksize;
		if (block_start >= len) {
			/*
			 * Comments copied from block_write_full_page_endio:
			 *
			 * The page straddles i_size.  It must be zeroed out on
			 * each and every writepage invocation because it may
			 * be mmapped.  "A file is mapped in multiples of the
			 * page size.  For a file that is not a multiple of
			 * the  page size, the remaining memory is zeroed when
			 * mapped, and writes to that region are not written
			 * out to the file."
			 */
			zero_user_segment(page, block_start, block_end);
			clear_buffer_dirty(bh);
			set_buffer_uptodate(bh);
			continue;
		}
		clear_buffer_dirty(bh);
		ret = io_submit_add_bh(io, io_page, inode, wbc, bh);
		if (ret) {
			set_page_dirty(page);
			break;
		}
	}
	unlock_page(page);
	put_io_page(io_page);
	return ret;
}
Ejemplo n.º 18
0
Archivo: inline.c Proyecto: mdamt/linux
int f2fs_convert_inline_page(struct dnode_of_data *dn, struct page *page)
{
	struct f2fs_io_info fio = {
		.sbi = F2FS_I_SB(dn->inode),
		.type = DATA,
		.op = REQ_OP_WRITE,
		.op_flags = REQ_SYNC | REQ_PRIO,
		.page = page,
		.encrypted_page = NULL,
	};
	int dirty, err;

	if (!f2fs_exist_data(dn->inode))
		goto clear_out;

	err = f2fs_reserve_block(dn, 0);
	if (err)
		return err;

	f2fs_bug_on(F2FS_P_SB(page), PageWriteback(page));

	read_inline_data(page, dn->inode_page);
	set_page_dirty(page);

	/* clear dirty state */
	dirty = clear_page_dirty_for_io(page);

	/* write data page to try to make data consistent */
	set_page_writeback(page);
	fio.old_blkaddr = dn->data_blkaddr;
	set_inode_flag(dn->inode, FI_HOT_DATA);
	write_data_page(dn, &fio);
	f2fs_wait_on_page_writeback(page, DATA, true);
	if (dirty) {
		inode_dec_dirty_pages(dn->inode);
		remove_dirty_inode(dn->inode);
	}

	/* this converted inline_data should be recovered. */
	set_inode_flag(dn->inode, FI_APPEND_WRITE);

	/* clear inline data and flag after data writeback */
	truncate_inline_inode(dn->inode, dn->inode_page, 0);
	clear_inline_node(dn->inode_page);
clear_out:
	stat_dec_inline_inode(dn->inode);
	clear_inode_flag(dn->inode, FI_INLINE_DATA);
	f2fs_put_dnode(dn);
	return 0;
}

int f2fs_convert_inline_inode(struct inode *inode)
{
	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
	struct dnode_of_data dn;
	struct page *ipage, *page;
	int err = 0;

	if (!f2fs_has_inline_data(inode))
		return 0;

	page = f2fs_grab_cache_page(inode->i_mapping, 0, false);
	if (!page)
		return -ENOMEM;

	f2fs_lock_op(sbi);

	ipage = get_node_page(sbi, inode->i_ino);
	if (IS_ERR(ipage)) {
		err = PTR_ERR(ipage);
		goto out;
	}

	set_new_dnode(&dn, inode, ipage, ipage, 0);

	if (f2fs_has_inline_data(inode))
		err = f2fs_convert_inline_page(&dn, page);

	f2fs_put_dnode(&dn);
out:
	f2fs_unlock_op(sbi);

	f2fs_put_page(page, 1);

	f2fs_balance_fs(sbi, dn.node_changed);

	return err;
}

int f2fs_write_inline_data(struct inode *inode, struct page *page)
{
	void *src_addr, *dst_addr;
	struct dnode_of_data dn;
	int err;

	set_new_dnode(&dn, inode, NULL, NULL, 0);
	err = get_dnode_of_data(&dn, 0, LOOKUP_NODE);
	if (err)
		return err;

	if (!f2fs_has_inline_data(inode)) {
		f2fs_put_dnode(&dn);
		return -EAGAIN;
	}

	f2fs_bug_on(F2FS_I_SB(inode), page->index);

	f2fs_wait_on_page_writeback(dn.inode_page, NODE, true);
	src_addr = kmap_atomic(page);
	dst_addr = inline_data_addr(dn.inode_page);
	memcpy(dst_addr, src_addr, MAX_INLINE_DATA);
	kunmap_atomic(src_addr);
	set_page_dirty(dn.inode_page);

	set_inode_flag(inode, FI_APPEND_WRITE);
	set_inode_flag(inode, FI_DATA_EXIST);

	clear_inline_node(dn.inode_page);
	f2fs_put_dnode(&dn);
	return 0;
}
Ejemplo n.º 19
0
/**
 * ntfs_mft_writepage - check if a metadata page contains dirty mft records
 * @page:	metadata page possibly containing dirty mft records
 * @wbc:	writeback control structure
 *
 * This is called from the VM when it wants to have a dirty $MFT/$DATA metadata
 * page cache page cleaned.  The VM has already locked the page and marked it
 * clean.  Instead of writing the page as a conventional ->writepage function
 * would do, we check if the page still contains any dirty mft records (it must
 * have done at some point in the past since the page was marked dirty) and if
 * none are found, i.e. all mft records are clean, we unlock the page and
 * return.  The VM is then free to do with the page as it pleases.  If on the
 * other hand we do find any dirty mft records in the page, we redirty the page
 * before unlocking it and returning so the VM knows that the page is still
 * busy and cannot be thrown out.
 *
 * Note, we do not actually write any dirty mft records here because they are
 * dirty inodes and hence will be written by the VFS inode dirty code paths.
 * There is no need to write them from the VM page dirty code paths, too and in
 * fact once we implement journalling it would be a complete nightmare having
 * two code paths leading to mft record writeout.
 */
static int ntfs_mft_writepage(struct page *page, struct writeback_control *wbc)
{
	struct inode *mft_vi = page->mapping->host;
	struct super_block *sb = mft_vi->i_sb;
	ntfs_volume *vol = NTFS_SB(sb);
	u8 *maddr;
	MFT_RECORD *m;
	ntfs_inode **extent_nis;
	unsigned long mft_no;
	int nr, i, j;
	BOOL is_dirty = FALSE;

	BUG_ON(!PageLocked(page));
	BUG_ON(PageWriteback(page));
	BUG_ON(mft_vi != vol->mft_ino);
	/* The first mft record number in the page. */
	mft_no = page->index << (PAGE_CACHE_SHIFT - vol->mft_record_size_bits);
	/* Number of mft records in the page. */
	nr = PAGE_CACHE_SIZE >> vol->mft_record_size_bits;
	BUG_ON(!nr);
	ntfs_debug("Entering for %i inodes starting at 0x%lx.", nr, mft_no);
	/* Iterate over the mft records in the page looking for a dirty one. */
	maddr = (u8*)kmap(page);
	for (i = 0; i < nr; ++i, ++mft_no, maddr += vol->mft_record_size) {
		struct inode *vi;
		ntfs_inode *ni, *eni;
		ntfs_attr na;

		na.mft_no = mft_no;
		na.name = NULL;
		na.name_len = 0;
		na.type = AT_UNUSED;
		/*
		 * Check if the inode corresponding to this mft record is in
		 * the VFS inode cache and obtain a reference to it if it is.
		 */
		ntfs_debug("Looking for inode 0x%lx in icache.", mft_no);
		/*
		 * For inode 0, i.e. $MFT itself, we cannot use ilookup5() from
		 * here or we deadlock because the inode is already locked by
		 * the kernel (fs/fs-writeback.c::__sync_single_inode()) and
		 * ilookup5() waits until the inode is unlocked before
		 * returning it and it never gets unlocked because
		 * ntfs_mft_writepage() never returns.  )-:  Fortunately, we
		 * have inode 0 pinned in icache for the duration of the mount
		 * so we can access it directly.
		 */
		if (!mft_no) {
			/* Balance the below iput(). */
			vi = igrab(mft_vi);
			BUG_ON(vi != mft_vi);
		} else
			vi = ilookup5(sb, mft_no, (test_t)ntfs_test_inode, &na);
		if (vi) {
			ntfs_debug("Inode 0x%lx is in icache.", mft_no);
			/* The inode is in icache.  Check if it is dirty. */
			ni = NTFS_I(vi);
			if (!NInoDirty(ni)) {
				/* The inode is not dirty, skip this record. */
				ntfs_debug("Inode 0x%lx is not dirty, "
						"continuing search.", mft_no);
				iput(vi);
				continue;
			}
			ntfs_debug("Inode 0x%lx is dirty, aborting search.",
					mft_no);
			/* The inode is dirty, no need to search further. */
			iput(vi);
			is_dirty = TRUE;
			break;
		}
		ntfs_debug("Inode 0x%lx is not in icache.", mft_no);
		/* The inode is not in icache. */
		/* Skip the record if it is not a mft record (type "FILE"). */
		if (!ntfs_is_mft_recordp(maddr)) {
			ntfs_debug("Mft record 0x%lx is not a FILE record, "
					"continuing search.", mft_no);
			continue;
		}
		m = (MFT_RECORD*)maddr;
		/*
		 * Skip the mft record if it is not in use.  FIXME:  What about
		 * deleted/deallocated (extent) inodes?  (AIA)
		 */
		if (!(m->flags & MFT_RECORD_IN_USE)) {
			ntfs_debug("Mft record 0x%lx is not in use, "
					"continuing search.", mft_no);
			continue;
		}
		/* Skip the mft record if it is a base inode. */
		if (!m->base_mft_record) {
			ntfs_debug("Mft record 0x%lx is a base record, "
					"continuing search.", mft_no);
			continue;
		}
		/*
		 * This is an extent mft record.  Check if the inode
		 * corresponding to its base mft record is in icache.
		 */
		na.mft_no = MREF_LE(m->base_mft_record);
		ntfs_debug("Mft record 0x%lx is an extent record.  Looking "
				"for base inode 0x%lx in icache.", mft_no,
				na.mft_no);
		vi = ilookup5(sb, na.mft_no, (test_t)ntfs_test_inode,
				&na);
		if (!vi) {
			/*
			 * The base inode is not in icache.  Skip this extent
			 * mft record.
			 */
			ntfs_debug("Base inode 0x%lx is not in icache, "
					"continuing search.", na.mft_no);
			continue;
		}
		ntfs_debug("Base inode 0x%lx is in icache.", na.mft_no);
		/*
		 * The base inode is in icache.  Check if it has the extent
		 * inode corresponding to this extent mft record attached.
		 */
		ni = NTFS_I(vi);
		down(&ni->extent_lock);
		if (ni->nr_extents <= 0) {
			/*
			 * The base inode has no attached extent inodes.  Skip
			 * this extent mft record.
			 */
			up(&ni->extent_lock);
			iput(vi);
			continue;
		}
		/* Iterate over the attached extent inodes. */
		extent_nis = ni->ext.extent_ntfs_inos;
		for (eni = NULL, j = 0; j < ni->nr_extents; ++j) {
			if (mft_no == extent_nis[j]->mft_no) {
				/*
				 * Found the extent inode corresponding to this
				 * extent mft record.
				 */
				eni = extent_nis[j];
				break;
			}
		}
		/*
		 * If the extent inode was not attached to the base inode, skip
		 * this extent mft record.
		 */
		if (!eni) {
			up(&ni->extent_lock);
			iput(vi);
			continue;
		}
		/*
		 * Found the extent inode corrsponding to this extent mft
		 * record.  If it is dirty, no need to search further.
		 */
		if (NInoDirty(eni)) {
			up(&ni->extent_lock);
			iput(vi);
			is_dirty = TRUE;
			break;
		}
		/* The extent inode is not dirty, so do the next record. */
		up(&ni->extent_lock);
		iput(vi);
	}
	kunmap(page);
	/* If a dirty mft record was found, redirty the page. */
	if (is_dirty) {
		ntfs_debug("Inode 0x%lx is dirty.  Redirtying the page "
				"starting at inode 0x%lx.", mft_no,
				page->index << (PAGE_CACHE_SHIFT -
				vol->mft_record_size_bits));
		redirty_page_for_writepage(wbc, page);
		unlock_page(page);
	} else {
		/*
		 * Keep the VM happy.  This must be done otherwise the
		 * radix-tree tag PAGECACHE_TAG_DIRTY remains set even though
		 * the page is clean.
		 */
		BUG_ON(PageWriteback(page));
		set_page_writeback(page);
		unlock_page(page);
		end_page_writeback(page);
	}
	ntfs_debug("Done.");
	return 0;
}