Commit eb47b800 authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: add address space operations for data 



This adds address space operations for data.

- F2FS supports readpages(), writepages(), and direct_IO().

- Because of out-of-place writes, f2fs_direct_IO() does not write data in place.

Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
parent fbfa2cc5

fs/f2fs/data.c

0 → 100644
+701 −0
Original line number Diff line number Diff line 
/**

 * 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 "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, RDONLY_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);



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

	if (err) {

		f2fs_put_page(page, 1);

		return ERR_PTR(err);

	}

	unlock_page(page);

	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, RDONLY_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) {

		f2fs_put_page(page, 1);

		return ERR_PTR(err);

	}

	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, 0);

	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);

	} else {

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

		if (err) {

			f2fs_put_page(page, 1);

			return ERR_PTR(err);

		}

	}

	SetPageUptodate(page);



	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.

 * Read operation is synchronous, and caller must unlock the 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;

	bool sync = (type == READ_SYNC);

	struct bio *bio;



	/* This page can be already read by other threads */

	if (PageUptodate(page)) {

		if (!sync)

			unlock_page(page);

		return 0;

	}



	down_read(&sbi->bio_sem);



	/* Allocate a new bio */

	bio = f2fs_bio_alloc(bdev, blk_addr << (sbi->log_blocksize - 9),

				1, GFP_NOFS | __GFP_HIGH);



	/* Initialize the bio */

	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);

		return -EFAULT;

	}



	submit_bio(type, bio);

	up_read(&sbi->bio_sem);



	/* wait for read completion if sync */

	if (sync) {

		lock_page(page);

		if (PageError(page))

			return -EIO;

	}

	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, RDONLY_NODE);

	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;

	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);

	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, RDONLY_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);

		F2FS_I(inode)->data_version =

			le64_to_cpu(F2FS_CKPT(sbi)->checkpoint_ver);

	}

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



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 = generic_writepages(mapping, wbc);

	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, 0);

	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);

		return 0;

	}



	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) {

			f2fs_put_page(page, 1);

			return err;

		}

	}

	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 0;

}



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;

}



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,

};

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