[linux-2.6-block.git] / fs / f2fs / data.c

/*
 * fs/f2fs/data.c
 *
 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
 *             http://www.samsung.com/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/fs.h>
#include <linux/f2fs_fs.h>
#include <linux/buffer_head.h>
#include <linux/mpage.h>
#include <linux/writeback.h>
#include <linux/backing-dev.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/prefetch.h>

#include "f2fs.h"
#include "node.h"
#include "segment.h"

/*
 * Lock ordering for the change of data block address:
 * ->data_page
 *  ->node_page
 *    update block addresses in the node page
 */
static void __set_data_blkaddr(struct dnode_of_data *dn, block_t new_addr)
{
	struct f2fs_node *rn;
	__le32 *addr_array;
	struct page *node_page = dn->node_page;
	unsigned int ofs_in_node = dn->ofs_in_node;

	wait_on_page_writeback(node_page);

	rn = (struct f2fs_node *)page_address(node_page);

	/* Get physical address of data block */
	addr_array = blkaddr_in_node(rn);
	addr_array[ofs_in_node] = cpu_to_le32(new_addr);
	set_page_dirty(node_page);
}

int reserve_new_block(struct dnode_of_data *dn)
{
	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);

	if (is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC))
		return -EPERM;
	if (!inc_valid_block_count(sbi, dn->inode, 1))
		return -ENOSPC;

	__set_data_blkaddr(dn, NEW_ADDR);
	dn->data_blkaddr = NEW_ADDR;
	sync_inode_page(dn);
	return 0;
}

static int check_extent_cache(struct inode *inode, pgoff_t pgofs,
					struct buffer_head *bh_result)
{
	struct f2fs_inode_info *fi = F2FS_I(inode);
	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	pgoff_t start_fofs, end_fofs;
	block_t start_blkaddr;

	read_lock(&fi->ext.ext_lock);
	if (fi->ext.len == 0) {
		read_unlock(&fi->ext.ext_lock);
		return 0;
	}

	sbi->total_hit_ext++;
	start_fofs = fi->ext.fofs;
	end_fofs = fi->ext.fofs + fi->ext.len - 1;
	start_blkaddr = fi->ext.blk_addr;

	if (pgofs >= start_fofs && pgofs <= end_fofs) {
		unsigned int blkbits = inode->i_sb->s_blocksize_bits;
		size_t count;

		clear_buffer_new(bh_result);
		map_bh(bh_result, inode->i_sb,
				start_blkaddr + pgofs - start_fofs);
		count = end_fofs - pgofs + 1;
		if (count < (UINT_MAX >> blkbits))
			bh_result->b_size = (count << blkbits);
		else
			bh_result->b_size = UINT_MAX;

		sbi->read_hit_ext++;
		read_unlock(&fi->ext.ext_lock);
		return 1;
	}
	read_unlock(&fi->ext.ext_lock);
	return 0;
}

void update_extent_cache(block_t blk_addr, struct dnode_of_data *dn)
{
	struct f2fs_inode_info *fi = F2FS_I(dn->inode);
	pgoff_t fofs, start_fofs, end_fofs;
	block_t start_blkaddr, end_blkaddr;

	BUG_ON(blk_addr == NEW_ADDR);
	fofs = start_bidx_of_node(ofs_of_node(dn->node_page)) + dn->ofs_in_node;

	/* Update the page address in the parent node */
	__set_data_blkaddr(dn, blk_addr);

	write_lock(&fi->ext.ext_lock);

	start_fofs = fi->ext.fofs;
	end_fofs = fi->ext.fofs + fi->ext.len - 1;
	start_blkaddr = fi->ext.blk_addr;
	end_blkaddr = fi->ext.blk_addr + fi->ext.len - 1;

	/* Drop and initialize the matched extent */
	if (fi->ext.len == 1 && fofs == start_fofs)
		fi->ext.len = 0;

	/* Initial extent */
	if (fi->ext.len == 0) {
		if (blk_addr != NULL_ADDR) {
			fi->ext.fofs = fofs;
			fi->ext.blk_addr = blk_addr;
			fi->ext.len = 1;
		}
		goto end_update;
	}

	/* Frone merge */
	if (fofs == start_fofs - 1 && blk_addr == start_blkaddr - 1) {
		fi->ext.fofs--;
		fi->ext.blk_addr--;
		fi->ext.len++;
		goto end_update;
	}

	/* Back merge */
	if (fofs == end_fofs + 1 && blk_addr == end_blkaddr + 1) {
		fi->ext.len++;
		goto end_update;
	}

	/* Split the existing extent */
	if (fi->ext.len > 1 &&
		fofs >= start_fofs && fofs <= end_fofs) {
		if ((end_fofs - fofs) < (fi->ext.len >> 1)) {
			fi->ext.len = fofs - start_fofs;
		} else {
			fi->ext.fofs = fofs + 1;
			fi->ext.blk_addr = start_blkaddr +
					fofs - start_fofs + 1;
			fi->ext.len -= fofs - start_fofs + 1;
		}
		goto end_update;
	}
	write_unlock(&fi->ext.ext_lock);
	return;

end_update:
	write_unlock(&fi->ext.ext_lock);
	sync_inode_page(dn);
	return;
}

struct page *find_data_page(struct inode *inode, pgoff_t index)
{
	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	struct address_space *mapping = inode->i_mapping;
	struct dnode_of_data dn;
	struct page *page;
	int err;

	page = find_get_page(mapping, index);
	if (page && PageUptodate(page))
		return page;
	f2fs_put_page(page, 0);

	set_new_dnode(&dn, inode, NULL, NULL, 0);
	err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
	if (err)
		return ERR_PTR(err);
	f2fs_put_dnode(&dn);

	if (dn.data_blkaddr == NULL_ADDR)
		return ERR_PTR(-ENOENT);

	/* By fallocate(), there is no cached page, but with NEW_ADDR */
	if (dn.data_blkaddr == NEW_ADDR)
		return ERR_PTR(-EINVAL);

	page = grab_cache_page(mapping, index);
	if (!page)
		return ERR_PTR(-ENOMEM);

	if (PageUptodate(page)) {
		unlock_page(page);
		return page;
	}

	err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
	wait_on_page_locked(page);
	if (!PageUptodate(page)) {
		f2fs_put_page(page, 0);
		return ERR_PTR(-EIO);
	}
	return page;
}

/*
 * If it tries to access a hole, return an error.
 * Because, the callers, functions in dir.c and GC, should be able to know
 * whether this page exists or not.
 */
struct page *get_lock_data_page(struct inode *inode, pgoff_t index)
{
	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	struct address_space *mapping = inode->i_mapping;
	struct dnode_of_data dn;
	struct page *page;
	int err;

	set_new_dnode(&dn, inode, NULL, NULL, 0);
	err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
	if (err)
		return ERR_PTR(err);
	f2fs_put_dnode(&dn);

	if (dn.data_blkaddr == NULL_ADDR)
		return ERR_PTR(-ENOENT);

	page = grab_cache_page(mapping, index);
	if (!page)
		return ERR_PTR(-ENOMEM);

	if (PageUptodate(page))
		return page;

	BUG_ON(dn.data_blkaddr == NEW_ADDR);
	BUG_ON(dn.data_blkaddr == NULL_ADDR);

	err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
	if (err)
		return ERR_PTR(err);

	lock_page(page);
	if (!PageUptodate(page)) {
		f2fs_put_page(page, 1);
		return ERR_PTR(-EIO);
	}
	return page;
}

/*
 * Caller ensures that this data page is never allocated.
 * A new zero-filled data page is allocated in the page cache.
 */
struct page *get_new_data_page(struct inode *inode, pgoff_t index,
						bool new_i_size)
{
	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	struct address_space *mapping = inode->i_mapping;
	struct page *page;
	struct dnode_of_data dn;
	int err;

	set_new_dnode(&dn, inode, NULL, NULL, 0);
	err = get_dnode_of_data(&dn, index, ALLOC_NODE);
	if (err)
		return ERR_PTR(err);

	if (dn.data_blkaddr == NULL_ADDR) {
		if (reserve_new_block(&dn)) {
			f2fs_put_dnode(&dn);
			return ERR_PTR(-ENOSPC);
		}
	}
	f2fs_put_dnode(&dn);

	page = grab_cache_page(mapping, index);
	if (!page)
		return ERR_PTR(-ENOMEM);

	if (PageUptodate(page))
		return page;

	if (dn.data_blkaddr == NEW_ADDR) {
		zero_user_segment(page, 0, PAGE_CACHE_SIZE);
		SetPageUptodate(page);
	} else {
		err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
		if (err)
			return ERR_PTR(err);
		lock_page(page);
		if (!PageUptodate(page)) {
			f2fs_put_page(page, 1);
			return ERR_PTR(-EIO);
		}
	}

	if (new_i_size &&
		i_size_read(inode) < ((index + 1) << PAGE_CACHE_SHIFT)) {
		i_size_write(inode, ((index + 1) << PAGE_CACHE_SHIFT));
		mark_inode_dirty_sync(inode);
	}
	return page;
}

static void read_end_io(struct bio *bio, int err)
{
	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;

	do {
		struct page *page = bvec->bv_page;

		if (--bvec >= bio->bi_io_vec)
			prefetchw(&bvec->bv_page->flags);

		if (uptodate) {
			SetPageUptodate(page);
		} else {
			ClearPageUptodate(page);
			SetPageError(page);
		}
		unlock_page(page);
	} while (bvec >= bio->bi_io_vec);
	kfree(bio->bi_private);
	bio_put(bio);
}

/*
 * Fill the locked page with data located in the block address.
 * Return unlocked page.
 */
int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
					block_t blk_addr, int type)
{
	struct block_device *bdev = sbi->sb->s_bdev;
	struct bio *bio;

	down_read(&sbi->bio_sem);

	/* Allocate a new bio */
	bio = f2fs_bio_alloc(bdev, 1);

	/* Initialize the bio */
	bio->bi_sector = SECTOR_FROM_BLOCK(sbi, blk_addr);
	bio->bi_end_io = read_end_io;

	if (bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < PAGE_CACHE_SIZE) {
		kfree(bio->bi_private);
		bio_put(bio);
		up_read(&sbi->bio_sem);
		f2fs_put_page(page, 1);
		return -EFAULT;
	}

	submit_bio(type, bio);
	up_read(&sbi->bio_sem);
	return 0;
}

/*
 * This function should be used by the data read flow only where it
 * does not check the "create" flag that indicates block allocation.
 * The reason for this special functionality is to exploit VFS readahead
 * mechanism.
 */
static int get_data_block_ro(struct inode *inode, sector_t iblock,
			struct buffer_head *bh_result, int create)
{
	unsigned int blkbits = inode->i_sb->s_blocksize_bits;
	unsigned maxblocks = bh_result->b_size >> blkbits;
	struct dnode_of_data dn;
	pgoff_t pgofs;
	int err;

	/* Get the page offset from the block offset(iblock) */
	pgofs =	(pgoff_t)(iblock >> (PAGE_CACHE_SHIFT - blkbits));

	if (check_extent_cache(inode, pgofs, bh_result))
		return 0;

	/* When reading holes, we need its node page */
	set_new_dnode(&dn, inode, NULL, NULL, 0);
	err = get_dnode_of_data(&dn, pgofs, LOOKUP_NODE_RA);
	if (err)
		return (err == -ENOENT) ? 0 : err;

	/* It does not support data allocation */
	BUG_ON(create);

	if (dn.data_blkaddr != NEW_ADDR && dn.data_blkaddr != NULL_ADDR) {
		int i;
		unsigned int end_offset;

		end_offset = IS_INODE(dn.node_page) ?
				ADDRS_PER_INODE :
				ADDRS_PER_BLOCK;

		clear_buffer_new(bh_result);

		/* Give more consecutive addresses for the read ahead */
		for (i = 0; i < end_offset - dn.ofs_in_node; i++)
			if (((datablock_addr(dn.node_page,
							dn.ofs_in_node + i))
				!= (dn.data_blkaddr + i)) || maxblocks == i)
				break;
		map_bh(bh_result, inode->i_sb, dn.data_blkaddr);
		bh_result->b_size = (i << blkbits);
	}
	f2fs_put_dnode(&dn);
	return 0;
}

static int f2fs_read_data_page(struct file *file, struct page *page)
{
	return mpage_readpage(page, get_data_block_ro);
}

static int f2fs_read_data_pages(struct file *file,
			struct address_space *mapping,
			struct list_head *pages, unsigned nr_pages)
{
	return mpage_readpages(mapping, pages, nr_pages, get_data_block_ro);
}

int do_write_data_page(struct page *page)
{
	struct inode *inode = page->mapping->host;
	block_t old_blk_addr, new_blk_addr;
	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;

	old_blk_addr = dn.data_blkaddr;

	/* This page is already truncated */
	if (old_blk_addr == NULL_ADDR)
		goto out_writepage;

	set_page_writeback(page);

	/*
	 * If current allocation needs SSR,
	 * it had better in-place writes for updated data.
	 */
	if (old_blk_addr != NEW_ADDR && !is_cold_data(page) &&
				need_inplace_update(inode)) {
		rewrite_data_page(F2FS_SB(inode->i_sb), page,
						old_blk_addr);
	} else {
		write_data_page(inode, page, &dn,
				old_blk_addr, &new_blk_addr);
		update_extent_cache(new_blk_addr, &dn);
	}
out_writepage:
	f2fs_put_dnode(&dn);
	return err;
}

static int f2fs_write_data_page(struct page *page,
					struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	loff_t i_size = i_size_read(inode);
	const pgoff_t end_index = ((unsigned long long) i_size)
							>> PAGE_CACHE_SHIFT;
	unsigned offset;
	int err = 0;

	if (page->index < end_index)
		goto out;

	/*
	 * If the offset is out-of-range of file size,
	 * this page does not have to be written to disk.
	 */
	offset = i_size & (PAGE_CACHE_SIZE - 1);
	if ((page->index >= end_index + 1) || !offset) {
		if (S_ISDIR(inode->i_mode)) {
			dec_page_count(sbi, F2FS_DIRTY_DENTS);
			inode_dec_dirty_dents(inode);
		}
		goto unlock_out;
	}

	zero_user_segment(page, offset, PAGE_CACHE_SIZE);
out:
	if (sbi->por_doing)
		goto redirty_out;

	if (wbc->for_reclaim && !S_ISDIR(inode->i_mode) && !is_cold_data(page))
		goto redirty_out;

	mutex_lock_op(sbi, DATA_WRITE);
	if (S_ISDIR(inode->i_mode)) {
		dec_page_count(sbi, F2FS_DIRTY_DENTS);
		inode_dec_dirty_dents(inode);
	}
	err = do_write_data_page(page);
	if (err && err != -ENOENT) {
		wbc->pages_skipped++;
		set_page_dirty(page);
	}
	mutex_unlock_op(sbi, DATA_WRITE);

	if (wbc->for_reclaim)
		f2fs_submit_bio(sbi, DATA, true);

	if (err == -ENOENT)
		goto unlock_out;

	clear_cold_data(page);
	unlock_page(page);

	if (!wbc->for_reclaim && !S_ISDIR(inode->i_mode))
		f2fs_balance_fs(sbi);
	return 0;

unlock_out:
	unlock_page(page);
	return (err == -ENOENT) ? 0 : err;

redirty_out:
	wbc->pages_skipped++;
	set_page_dirty(page);
	return AOP_WRITEPAGE_ACTIVATE;
}

#define MAX_DESIRED_PAGES_WP	4096

static int __f2fs_writepage(struct page *page, struct writeback_control *wbc,
			void *data)
{
	struct address_space *mapping = data;
	int ret = mapping->a_ops->writepage(page, wbc);
	mapping_set_error(mapping, ret);
	return ret;
}

static int f2fs_write_data_pages(struct address_space *mapping,
			    struct writeback_control *wbc)
{
	struct inode *inode = mapping->host;
	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	int ret;
	long excess_nrtw = 0, desired_nrtw;

	if (wbc->nr_to_write < MAX_DESIRED_PAGES_WP) {
		desired_nrtw = MAX_DESIRED_PAGES_WP;
		excess_nrtw = desired_nrtw - wbc->nr_to_write;
		wbc->nr_to_write = desired_nrtw;
	}

	if (!S_ISDIR(inode->i_mode))
		mutex_lock(&sbi->writepages);
	ret = write_cache_pages(mapping, wbc, __f2fs_writepage, mapping);
	if (!S_ISDIR(inode->i_mode))
		mutex_unlock(&sbi->writepages);
	f2fs_submit_bio(sbi, DATA, (wbc->sync_mode == WB_SYNC_ALL));

	remove_dirty_dir_inode(inode);

	wbc->nr_to_write -= excess_nrtw;
	return ret;
}

static int f2fs_write_begin(struct file *file, struct address_space *mapping,
		loff_t pos, unsigned len, unsigned flags,
		struct page **pagep, void **fsdata)
{
	struct inode *inode = mapping->host;
	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	struct page *page;
	pgoff_t index = ((unsigned long long) pos) >> PAGE_CACHE_SHIFT;
	struct dnode_of_data dn;
	int err = 0;

	/* for nobh_write_end */
	*fsdata = NULL;

	f2fs_balance_fs(sbi);

	page = grab_cache_page_write_begin(mapping, index, flags);
	if (!page)
		return -ENOMEM;
	*pagep = page;

	mutex_lock_op(sbi, DATA_NEW);

	set_new_dnode(&dn, inode, NULL, NULL, 0);
	err = get_dnode_of_data(&dn, index, ALLOC_NODE);
	if (err) {
		mutex_unlock_op(sbi, DATA_NEW);
		f2fs_put_page(page, 1);
		return err;
	}

	if (dn.data_blkaddr == NULL_ADDR) {
		err = reserve_new_block(&dn);
		if (err) {
			f2fs_put_dnode(&dn);
			mutex_unlock_op(sbi, DATA_NEW);
			f2fs_put_page(page, 1);
			return err;
		}
	}
	f2fs_put_dnode(&dn);

	mutex_unlock_op(sbi, DATA_NEW);

	if ((len == PAGE_CACHE_SIZE) || PageUptodate(page))
		return 0;

	if ((pos & PAGE_CACHE_MASK) >= i_size_read(inode)) {
		unsigned start = pos & (PAGE_CACHE_SIZE - 1);
		unsigned end = start + len;

		/* Reading beyond i_size is simple: memset to zero */
		zero_user_segments(page, 0, start, end, PAGE_CACHE_SIZE);
		goto out;
	}

	if (dn.data_blkaddr == NEW_ADDR) {
		zero_user_segment(page, 0, PAGE_CACHE_SIZE);
	} else {
		err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
		if (err)
			return err;
		lock_page(page);
		if (!PageUptodate(page)) {
			f2fs_put_page(page, 1);
			return -EIO;
		}
	}
out:
	SetPageUptodate(page);
	clear_cold_data(page);
	return 0;
}

static ssize_t f2fs_direct_IO(int rw, struct kiocb *iocb,
		const struct iovec *iov, loff_t offset, unsigned long nr_segs)
{
	struct file *file = iocb->ki_filp;
	struct inode *inode = file->f_mapping->host;

	if (rw == WRITE)
		return 0;

	/* Needs synchronization with the cleaner */
	return blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
						  get_data_block_ro);
}

static void f2fs_invalidate_data_page(struct page *page, unsigned long offset)
{
	struct inode *inode = page->mapping->host;
	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	if (S_ISDIR(inode->i_mode) && PageDirty(page)) {
		dec_page_count(sbi, F2FS_DIRTY_DENTS);
		inode_dec_dirty_dents(inode);
	}
	ClearPagePrivate(page);
}

static int f2fs_release_data_page(struct page *page, gfp_t wait)
{
	ClearPagePrivate(page);
	return 1;
}

static int f2fs_set_data_page_dirty(struct page *page)
{
	struct address_space *mapping = page->mapping;
	struct inode *inode = mapping->host;

	SetPageUptodate(page);
	if (!PageDirty(page)) {
		__set_page_dirty_nobuffers(page);
		set_dirty_dir_page(inode, page);
		return 1;
	}
	return 0;
}

static sector_t f2fs_bmap(struct address_space *mapping, sector_t block)
{
	return generic_block_bmap(mapping, block, get_data_block_ro);
}

const struct address_space_operations f2fs_dblock_aops = {
	.readpage	= f2fs_read_data_page,
	.readpages	= f2fs_read_data_pages,
	.writepage	= f2fs_write_data_page,
	.writepages	= f2fs_write_data_pages,
	.write_begin	= f2fs_write_begin,
	.write_end	= nobh_write_end,
	.set_page_dirty	= f2fs_set_data_page_dirty,
	.invalidatepage	= f2fs_invalidate_data_page,
	.releasepage	= f2fs_release_data_page,
	.direct_IO	= f2fs_direct_IO,
	.bmap		= f2fs_bmap,
};
Commit	Line	Data
0a8165d7	1	/*
eb47b800 JK	2	* fs/f2fs/data.c
	3	*
	4	* Copyright (c) 2012 Samsung Electronics Co., Ltd.
	5	* http://www.samsung.com/
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*/
	11	#include <linux/fs.h>
	12	#include <linux/f2fs_fs.h>
	13	#include <linux/buffer_head.h>
	14	#include <linux/mpage.h>
	15	#include <linux/writeback.h>
	16	#include <linux/backing-dev.h>
	17	#include <linux/blkdev.h>
	18	#include <linux/bio.h>
690e4a3e	19	#include <linux/prefetch.h>
eb47b800 JK	20
	21	#include "f2fs.h"
	22	#include "node.h"
	23	#include "segment.h"
	24
0a8165d7	25	/*
eb47b800 JK	26	* Lock ordering for the change of data block address:
	27	* ->data_page
	28	* ->node_page
	29	* update block addresses in the node page
	30	*/
	31	static void __set_data_blkaddr(struct dnode_of_data *dn, block_t new_addr)
	32	{
	33	struct f2fs_node *rn;
	34	__le32 *addr_array;
	35	struct page *node_page = dn->node_page;
	36	unsigned int ofs_in_node = dn->ofs_in_node;
	37
	38	wait_on_page_writeback(node_page);
	39
	40	rn = (struct f2fs_node *)page_address(node_page);
	41
	42	/* Get physical address of data block */
	43	addr_array = blkaddr_in_node(rn);
	44	addr_array[ofs_in_node] = cpu_to_le32(new_addr);
	45	set_page_dirty(node_page);
	46	}
	47
	48	int reserve_new_block(struct dnode_of_data *dn)
	49	{
	50	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
	51
	52	if (is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC))
	53	return -EPERM;
	54	if (!inc_valid_block_count(sbi, dn->inode, 1))
	55	return -ENOSPC;
	56
	57	__set_data_blkaddr(dn, NEW_ADDR);
	58	dn->data_blkaddr = NEW_ADDR;
	59	sync_inode_page(dn);
	60	return 0;
	61	}
	62
	63	static int check_extent_cache(struct inode *inode, pgoff_t pgofs,
	64	struct buffer_head *bh_result)
	65	{
	66	struct f2fs_inode_info *fi = F2FS_I(inode);
	67	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	68	pgoff_t start_fofs, end_fofs;
	69	block_t start_blkaddr;
	70
	71	read_lock(&fi->ext.ext_lock);
	72	if (fi->ext.len == 0) {
	73	read_unlock(&fi->ext.ext_lock);
	74	return 0;
	75	}
	76
	77	sbi->total_hit_ext++;
	78	start_fofs = fi->ext.fofs;
	79	end_fofs = fi->ext.fofs + fi->ext.len - 1;
	80	start_blkaddr = fi->ext.blk_addr;
	81
	82	if (pgofs >= start_fofs && pgofs <= end_fofs) {
	83	unsigned int blkbits = inode->i_sb->s_blocksize_bits;
	84	size_t count;
	85
	86	clear_buffer_new(bh_result);
	87	map_bh(bh_result, inode->i_sb,
	88	start_blkaddr + pgofs - start_fofs);
	89	count = end_fofs - pgofs + 1;
90	if (count < (UINT_MAX >> blkbits))
91	bh_result->b_size = (count << blkbits);
92	else
93	bh_result->b_size = UINT_MAX;
94
95	sbi->read_hit_ext++;
96	read_unlock(&fi->ext.ext_lock);
97	return 1;
98	}
99	read_unlock(&fi->ext.ext_lock);
100	return 0;
101	}
102
103	void update_extent_cache(block_t blk_addr, struct dnode_of_data *dn)
104	{
105	struct f2fs_inode_info *fi = F2FS_I(dn->inode);
106	pgoff_t fofs, start_fofs, end_fofs;
107	block_t start_blkaddr, end_blkaddr;
108
109	BUG_ON(blk_addr == NEW_ADDR);
110	fofs = start_bidx_of_node(ofs_of_node(dn->node_page)) + dn->ofs_in_node;
111
112	/* Update the page address in the parent node */
113	__set_data_blkaddr(dn, blk_addr);
114
115	write_lock(&fi->ext.ext_lock);
116
117	start_fofs = fi->ext.fofs;
118	end_fofs = fi->ext.fofs + fi->ext.len - 1;
119	start_blkaddr = fi->ext.blk_addr;
120	end_blkaddr = fi->ext.blk_addr + fi->ext.len - 1;
121
122	/* Drop and initialize the matched extent */
123	if (fi->ext.len == 1 && fofs == start_fofs)
124	fi->ext.len = 0;
125
126	/* Initial extent */
127	if (fi->ext.len == 0) {
128	if (blk_addr != NULL_ADDR) {
129	fi->ext.fofs = fofs;
130	fi->ext.blk_addr = blk_addr;
131	fi->ext.len = 1;
132	}
133	goto end_update;
134	}
135
136	/* Frone merge */
137	if (fofs == start_fofs - 1 && blk_addr == start_blkaddr - 1) {
138	fi->ext.fofs--;
139	fi->ext.blk_addr--;
140	fi->ext.len++;
141	goto end_update;
142	}
143
144	/* Back merge */
145	if (fofs == end_fofs + 1 && blk_addr == end_blkaddr + 1) {
146	fi->ext.len++;
147	goto end_update;
148	}
149
150	/* Split the existing extent */
151	if (fi->ext.len > 1 &&
152	fofs >= start_fofs && fofs <= end_fofs) {
153	if ((end_fofs - fofs) < (fi->ext.len >> 1)) {
154	fi->ext.len = fofs - start_fofs;
155	} else {
156	fi->ext.fofs = fofs + 1;
157	fi->ext.blk_addr = start_blkaddr +
158	fofs - start_fofs + 1;
159	fi->ext.len -= fofs - start_fofs + 1;
160	}
161	goto end_update;
162	}
163	write_unlock(&fi->ext.ext_lock);
164	return;
165
166	end_update:
167	write_unlock(&fi->ext.ext_lock);
168	sync_inode_page(dn);
169	return;
170	}
171
172	struct page find_data_page(struct inode inode, pgoff_t index)
173	{
174	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
175	struct address_space *mapping = inode->i_mapping;
176	struct dnode_of_data dn;
177	struct page *page;
178	int err;
179
180	page = find_get_page(mapping, index);
181	if (page && PageUptodate(page))
182	return page;
183	f2fs_put_page(page, 0);
184
185	set_new_dnode(&dn, inode, NULL, NULL, 0);
266e97a8	186	err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
eb47b800 JK	187	if (err)
	188	return ERR_PTR(err);
	189	f2fs_put_dnode(&dn);
	190
	191	if (dn.data_blkaddr == NULL_ADDR)
	192	return ERR_PTR(-ENOENT);
	193
	194	/* By fallocate(), there is no cached page, but with NEW_ADDR */
	195	if (dn.data_blkaddr == NEW_ADDR)
	196	return ERR_PTR(-EINVAL);
	197
	198	page = grab_cache_page(mapping, index);
	199	if (!page)
	200	return ERR_PTR(-ENOMEM);
	201
393ff91f JK	202	if (PageUptodate(page)) {
	203	unlock_page(page);
	204	return page;
	205	}
	206
eb47b800	207	err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
393ff91f JK	208	wait_on_page_locked(page);
	209	if (!PageUptodate(page)) {
	210	f2fs_put_page(page, 0);
	211	return ERR_PTR(-EIO);
eb47b800	212	}
eb47b800 JK	213	return page;
	214	}
	215
0a8165d7	216	/*
eb47b800 JK	217	* If it tries to access a hole, return an error.
	218	* Because, the callers, functions in dir.c and GC, should be able to know
	219	* whether this page exists or not.
	220	*/
	221	struct page get_lock_data_page(struct inode inode, pgoff_t index)
	222	{
	223	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	224	struct address_space *mapping = inode->i_mapping;
	225	struct dnode_of_data dn;
	226	struct page *page;
	227	int err;
	228
	229	set_new_dnode(&dn, inode, NULL, NULL, 0);
266e97a8	230	err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
eb47b800 JK	231	if (err)
	232	return ERR_PTR(err);
	233	f2fs_put_dnode(&dn);
	234
	235	if (dn.data_blkaddr == NULL_ADDR)
	236	return ERR_PTR(-ENOENT);
	237
	238	page = grab_cache_page(mapping, index);
	239	if (!page)
	240	return ERR_PTR(-ENOMEM);
	241
	242	if (PageUptodate(page))
	243	return page;
	244
	245	BUG_ON(dn.data_blkaddr == NEW_ADDR);
	246	BUG_ON(dn.data_blkaddr == NULL_ADDR);
	247
	248	err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
393ff91f	249	if (err)
eb47b800	250	return ERR_PTR(err);
393ff91f JK	251
	252	lock_page(page);
	253	if (!PageUptodate(page)) {
	254	f2fs_put_page(page, 1);
	255	return ERR_PTR(-EIO);
eb47b800 JK	256	}
	257	return page;
	258	}
	259
0a8165d7	260	/*
eb47b800 JK	261	* Caller ensures that this data page is never allocated.
	262	* A new zero-filled data page is allocated in the page cache.
	263	*/
	264	struct page get_new_data_page(struct inode inode, pgoff_t index,
	265	bool new_i_size)
	266	{
	267	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	268	struct address_space *mapping = inode->i_mapping;
	269	struct page *page;
	270	struct dnode_of_data dn;
	271	int err;
	272
	273	set_new_dnode(&dn, inode, NULL, NULL, 0);
266e97a8	274	err = get_dnode_of_data(&dn, index, ALLOC_NODE);
eb47b800 JK	275	if (err)
	276	return ERR_PTR(err);
	277
	278	if (dn.data_blkaddr == NULL_ADDR) {
	279	if (reserve_new_block(&dn)) {
	280	f2fs_put_dnode(&dn);
	281	return ERR_PTR(-ENOSPC);
	282	}
	283	}
	284	f2fs_put_dnode(&dn);
	285
	286	page = grab_cache_page(mapping, index);
	287	if (!page)
	288	return ERR_PTR(-ENOMEM);
	289
	290	if (PageUptodate(page))
	291	return page;
	292
	293	if (dn.data_blkaddr == NEW_ADDR) {
	294	zero_user_segment(page, 0, PAGE_CACHE_SIZE);
393ff91f	295	SetPageUptodate(page);
eb47b800 JK	296	} else {
eb47b800 JK	297	err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
393ff91f	298	if (err)
eb47b800	299	return ERR_PTR(err);
393ff91f JK	300	lock_page(page);
	301	if (!PageUptodate(page)) {
	302	f2fs_put_page(page, 1);
	303	return ERR_PTR(-EIO);
eb47b800 JK	304	}
eb47b800 JK	305	}
eb47b800 JK	306
	307	if (new_i_size &&
	308	i_size_read(inode) < ((index + 1) << PAGE_CACHE_SHIFT)) {
	309	i_size_write(inode, ((index + 1) << PAGE_CACHE_SHIFT));
	310	mark_inode_dirty_sync(inode);
	311	}
	312	return page;
	313	}
	314
	315	static void read_end_io(struct bio *bio, int err)
	316	{
	317	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	318	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
	319
	320	do {
	321	struct page *page = bvec->bv_page;
	322
	323	if (--bvec >= bio->bi_io_vec)
	324	prefetchw(&bvec->bv_page->flags);
	325
	326	if (uptodate) {
	327	SetPageUptodate(page);
	328	} else {
	329	ClearPageUptodate(page);
	330	SetPageError(page);
	331	}
	332	unlock_page(page);
	333	} while (bvec >= bio->bi_io_vec);
	334	kfree(bio->bi_private);
	335	bio_put(bio);
	336	}
	337
0a8165d7	338	/*
eb47b800	339	* Fill the locked page with data located in the block address.
393ff91f	340	* Return unlocked page.
eb47b800 JK	341	*/
	342	int f2fs_readpage(struct f2fs_sb_info sbi, struct page page,
	343	block_t blk_addr, int type)
	344	{
	345	struct block_device *bdev = sbi->sb->s_bdev;
eb47b800 JK	346	struct bio *bio;
eb47b800 JK	347
eb47b800 JK	348	down_read(&sbi->bio_sem);
	349
	350	/* Allocate a new bio */
3cd8a239	351	bio = f2fs_bio_alloc(bdev, 1);
eb47b800 JK	352
eb47b800 JK	353	/* Initialize the bio */
3cd8a239	354	bio->bi_sector = SECTOR_FROM_BLOCK(sbi, blk_addr);
eb47b800	355	bio->bi_end_io = read_end_io;
3cd8a239	356
eb47b800 JK	357	if (bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < PAGE_CACHE_SIZE) {
	358	kfree(bio->bi_private);
	359	bio_put(bio);
	360	up_read(&sbi->bio_sem);
393ff91f	361	f2fs_put_page(page, 1);
eb47b800 JK	362	return -EFAULT;
	363	}
	364
	365	submit_bio(type, bio);
	366	up_read(&sbi->bio_sem);
eb47b800 JK	367	return 0;
	368	}
	369
0a8165d7	370	/*
eb47b800 JK	371	* This function should be used by the data read flow only where it
	372	* does not check the "create" flag that indicates block allocation.
	373	* The reason for this special functionality is to exploit VFS readahead
	374	* mechanism.
	375	*/
	376	static int get_data_block_ro(struct inode *inode, sector_t iblock,
	377	struct buffer_head *bh_result, int create)
	378	{
	379	unsigned int blkbits = inode->i_sb->s_blocksize_bits;
	380	unsigned maxblocks = bh_result->b_size >> blkbits;
	381	struct dnode_of_data dn;
	382	pgoff_t pgofs;
	383	int err;
	384
	385	/* Get the page offset from the block offset(iblock) */
	386	pgofs = (pgoff_t)(iblock >> (PAGE_CACHE_SHIFT - blkbits));
	387
	388	if (check_extent_cache(inode, pgofs, bh_result))
	389	return 0;
	390
	391	/* When reading holes, we need its node page */
	392	set_new_dnode(&dn, inode, NULL, NULL, 0);
266e97a8	393	err = get_dnode_of_data(&dn, pgofs, LOOKUP_NODE_RA);
eb47b800 JK	394	if (err)
	395	return (err == -ENOENT) ? 0 : err;
	396
	397	/* It does not support data allocation */
	398	BUG_ON(create);
	399
	400	if (dn.data_blkaddr != NEW_ADDR && dn.data_blkaddr != NULL_ADDR) {
	401	int i;
	402	unsigned int end_offset;
	403
	404	end_offset = IS_INODE(dn.node_page) ?
	405	ADDRS_PER_INODE :
	406	ADDRS_PER_BLOCK;
	407
	408	clear_buffer_new(bh_result);
	409
	410	/* Give more consecutive addresses for the read ahead */
	411	for (i = 0; i < end_offset - dn.ofs_in_node; i++)
	412	if (((datablock_addr(dn.node_page,
	413	dn.ofs_in_node + i))
	414	!= (dn.data_blkaddr + i)) \|\| maxblocks == i)
	415	break;
	416	map_bh(bh_result, inode->i_sb, dn.data_blkaddr);
	417	bh_result->b_size = (i << blkbits);
	418	}
	419	f2fs_put_dnode(&dn);
	420	return 0;
	421	}
	422
	423	static int f2fs_read_data_page(struct file file, struct page page)
	424	{
	425	return mpage_readpage(page, get_data_block_ro);
	426	}
	427
	428	static int f2fs_read_data_pages(struct file *file,
	429	struct address_space *mapping,
	430	struct list_head *pages, unsigned nr_pages)
	431	{
	432	return mpage_readpages(mapping, pages, nr_pages, get_data_block_ro);
	433	}
	434
	435	int do_write_data_page(struct page *page)
	436	{
	437	struct inode *inode = page->mapping->host;
eb47b800 JK	438	block_t old_blk_addr, new_blk_addr;
	439	struct dnode_of_data dn;
	440	int err = 0;
	441
	442	set_new_dnode(&dn, inode, NULL, NULL, 0);
266e97a8	443	err = get_dnode_of_data(&dn, page->index, LOOKUP_NODE);
eb47b800 JK	444	if (err)
	445	return err;
	446
	447	old_blk_addr = dn.data_blkaddr;
	448
	449	/* This page is already truncated */
	450	if (old_blk_addr == NULL_ADDR)
	451	goto out_writepage;
	452
	453	set_page_writeback(page);
	454
	455	/*
	456	* If current allocation needs SSR,
	457	* it had better in-place writes for updated data.
	458	*/
	459	if (old_blk_addr != NEW_ADDR && !is_cold_data(page) &&
	460	need_inplace_update(inode)) {
	461	rewrite_data_page(F2FS_SB(inode->i_sb), page,
	462	old_blk_addr);
	463	} else {
	464	write_data_page(inode, page, &dn,
	465	old_blk_addr, &new_blk_addr);
	466	update_extent_cache(new_blk_addr, &dn);
eb47b800 JK	467	}
	468	out_writepage:
	469	f2fs_put_dnode(&dn);
	470	return err;
	471	}
	472
	473	static int f2fs_write_data_page(struct page *page,
	474	struct writeback_control *wbc)
	475	{
	476	struct inode *inode = page->mapping->host;
	477	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	478	loff_t i_size = i_size_read(inode);
	479	const pgoff_t end_index = ((unsigned long long) i_size)
	480	>> PAGE_CACHE_SHIFT;
	481	unsigned offset;
	482	int err = 0;
	483
	484	if (page->index < end_index)
	485	goto out;
	486
	487	/*
	488	* If the offset is out-of-range of file size,
	489	* this page does not have to be written to disk.
	490	*/
	491	offset = i_size & (PAGE_CACHE_SIZE - 1);
	492	if ((page->index >= end_index + 1) \|\| !offset) {
	493	if (S_ISDIR(inode->i_mode)) {
	494	dec_page_count(sbi, F2FS_DIRTY_DENTS);
	495	inode_dec_dirty_dents(inode);
	496	}
	497	goto unlock_out;
	498	}
	499
	500	zero_user_segment(page, offset, PAGE_CACHE_SIZE);
	501	out:
	502	if (sbi->por_doing)
	503	goto redirty_out;
	504
	505	if (wbc->for_reclaim && !S_ISDIR(inode->i_mode) && !is_cold_data(page))
	506	goto redirty_out;
	507
	508	mutex_lock_op(sbi, DATA_WRITE);
	509	if (S_ISDIR(inode->i_mode)) {
	510	dec_page_count(sbi, F2FS_DIRTY_DENTS);
	511	inode_dec_dirty_dents(inode);
	512	}
	513	err = do_write_data_page(page);
	514	if (err && err != -ENOENT) {
	515	wbc->pages_skipped++;
	516	set_page_dirty(page);
	517	}
	518	mutex_unlock_op(sbi, DATA_WRITE);
	519
	520	if (wbc->for_reclaim)
	521	f2fs_submit_bio(sbi, DATA, true);
	522
	523	if (err == -ENOENT)
	524	goto unlock_out;
	525
	526	clear_cold_data(page);
	527	unlock_page(page);
	528
	529	if (!wbc->for_reclaim && !S_ISDIR(inode->i_mode))
	530	f2fs_balance_fs(sbi);
531	return 0;
532
533	unlock_out:
534	unlock_page(page);
535	return (err == -ENOENT) ? 0 : err;
536
537	redirty_out:
538	wbc->pages_skipped++;
539	set_page_dirty(page);
540	return AOP_WRITEPAGE_ACTIVATE;
541	}
542
543	#define MAX_DESIRED_PAGES_WP 4096
544
fa9150a8 NJ	545	static int __f2fs_writepage(struct page page, struct writeback_control wbc,
	546	void *data)
	547	{
	548	struct address_space *mapping = data;
	549	int ret = mapping->a_ops->writepage(page, wbc);
	550	mapping_set_error(mapping, ret);
	551	return ret;
	552	}
	553
25ca923b	554	static int f2fs_write_data_pages(struct address_space *mapping,
eb47b800 JK	555	struct writeback_control *wbc)
	556	{
	557	struct inode *inode = mapping->host;
	558	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	559	int ret;
	560	long excess_nrtw = 0, desired_nrtw;
	561
	562	if (wbc->nr_to_write < MAX_DESIRED_PAGES_WP) {
	563	desired_nrtw = MAX_DESIRED_PAGES_WP;
	564	excess_nrtw = desired_nrtw - wbc->nr_to_write;
	565	wbc->nr_to_write = desired_nrtw;
	566	}
	567
	568	if (!S_ISDIR(inode->i_mode))
	569	mutex_lock(&sbi->writepages);
fa9150a8	570	ret = write_cache_pages(mapping, wbc, __f2fs_writepage, mapping);
eb47b800 JK	571	if (!S_ISDIR(inode->i_mode))
	572	mutex_unlock(&sbi->writepages);
	573	f2fs_submit_bio(sbi, DATA, (wbc->sync_mode == WB_SYNC_ALL));
	574
	575	remove_dirty_dir_inode(inode);
	576
	577	wbc->nr_to_write -= excess_nrtw;
	578	return ret;
	579	}
	580
	581	static int f2fs_write_begin(struct file file, struct address_space mapping,
	582	loff_t pos, unsigned len, unsigned flags,
	583	struct page pagep, void fsdata)
	584	{
	585	struct inode *inode = mapping->host;
	586	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	587	struct page *page;
	588	pgoff_t index = ((unsigned long long) pos) >> PAGE_CACHE_SHIFT;
	589	struct dnode_of_data dn;
	590	int err = 0;
	591
	592	/* for nobh_write_end */
	593	*fsdata = NULL;
	594
	595	f2fs_balance_fs(sbi);
	596
	597	page = grab_cache_page_write_begin(mapping, index, flags);
	598	if (!page)
	599	return -ENOMEM;
	600	*pagep = page;
	601
	602	mutex_lock_op(sbi, DATA_NEW);
	603
	604	set_new_dnode(&dn, inode, NULL, NULL, 0);
266e97a8	605	err = get_dnode_of_data(&dn, index, ALLOC_NODE);
eb47b800 JK	606	if (err) {
	607	mutex_unlock_op(sbi, DATA_NEW);
	608	f2fs_put_page(page, 1);
	609	return err;
	610	}
	611
	612	if (dn.data_blkaddr == NULL_ADDR) {
	613	err = reserve_new_block(&dn);
	614	if (err) {
	615	f2fs_put_dnode(&dn);
	616	mutex_unlock_op(sbi, DATA_NEW);
	617	f2fs_put_page(page, 1);
	618	return err;
	619	}
	620	}
	621	f2fs_put_dnode(&dn);
	622
	623	mutex_unlock_op(sbi, DATA_NEW);
	624
	625	if ((len == PAGE_CACHE_SIZE) \|\| PageUptodate(page))
	626	return 0;
	627
	628	if ((pos & PAGE_CACHE_MASK) >= i_size_read(inode)) {
	629	unsigned start = pos & (PAGE_CACHE_SIZE - 1);
	630	unsigned end = start + len;
	631
	632	/* Reading beyond i_size is simple: memset to zero */
	633	zero_user_segments(page, 0, start, end, PAGE_CACHE_SIZE);
393ff91f	634	goto out;
eb47b800 JK	635	}
	636
	637	if (dn.data_blkaddr == NEW_ADDR) {
	638	zero_user_segment(page, 0, PAGE_CACHE_SIZE);
	639	} else {
	640	err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
393ff91f	641	if (err)
eb47b800	642	return err;
393ff91f JK	643	lock_page(page);
	644	if (!PageUptodate(page)) {
	645	f2fs_put_page(page, 1);
	646	return -EIO;
eb47b800 JK	647	}
eb47b800 JK	648	}
393ff91f	649	out:
eb47b800 JK	650	SetPageUptodate(page);
	651	clear_cold_data(page);
	652	return 0;
	653	}
	654
	655	static ssize_t f2fs_direct_IO(int rw, struct kiocb *iocb,
	656	const struct iovec *iov, loff_t offset, unsigned long nr_segs)
	657	{
	658	struct file *file = iocb->ki_filp;
	659	struct inode *inode = file->f_mapping->host;
	660
	661	if (rw == WRITE)
	662	return 0;
	663
	664	/* Needs synchronization with the cleaner */
	665	return blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
	666	get_data_block_ro);
	667	}
	668
	669	static void f2fs_invalidate_data_page(struct page *page, unsigned long offset)
	670	{
	671	struct inode *inode = page->mapping->host;
	672	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
	673	if (S_ISDIR(inode->i_mode) && PageDirty(page)) {
	674	dec_page_count(sbi, F2FS_DIRTY_DENTS);
	675	inode_dec_dirty_dents(inode);
	676	}
	677	ClearPagePrivate(page);
	678	}
	679
	680	static int f2fs_release_data_page(struct page *page, gfp_t wait)
	681	{
	682	ClearPagePrivate(page);
c3850aa1	683	return 1;
eb47b800 JK	684	}
	685
	686	static int f2fs_set_data_page_dirty(struct page *page)
	687	{
	688	struct address_space *mapping = page->mapping;
	689	struct inode *inode = mapping->host;
	690
	691	SetPageUptodate(page);
	692	if (!PageDirty(page)) {
	693	__set_page_dirty_nobuffers(page);
	694	set_dirty_dir_page(inode, page);
	695	return 1;
	696	}
	697	return 0;
	698	}
	699
c01e54b7 JK	700	static sector_t f2fs_bmap(struct address_space *mapping, sector_t block)
	701	{
	702	return generic_block_bmap(mapping, block, get_data_block_ro);
	703	}
	704
eb47b800 JK	705	const struct address_space_operations f2fs_dblock_aops = {
	706	.readpage = f2fs_read_data_page,
	707	.readpages = f2fs_read_data_pages,
	708	.writepage = f2fs_write_data_page,
	709	.writepages = f2fs_write_data_pages,
	710	.write_begin = f2fs_write_begin,
	711	.write_end = nobh_write_end,
	712	.set_page_dirty = f2fs_set_data_page_dirty,
	713	.invalidatepage = f2fs_invalidate_data_page,
	714	.releasepage = f2fs_release_data_page,
	715	.direct_IO = f2fs_direct_IO,
c01e54b7	716	.bmap = f2fs_bmap,
eb47b800	717	};