/*
 *	fs/bfs/file.c
 *	BFS file operations.
 *	Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com>
 *
 *	Make the file block allocation algorithm understand the size
 *	of the underlying block device.
 *	Copyright (C) 2007 Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
 *
 */

#include <linux/fs.h>
#include <linux/buffer_head.h>
#include "bfs.h"

#undef DEBUG

#ifdef DEBUG
#define dprintf(x...)	printf(x)
#else
#define dprintf(x...)
#endif

const struct file_operations bfs_file_operations = {
	.llseek 	= generic_file_llseek,
	.read_iter	= generic_file_read_iter,
	.write_iter	= generic_file_write_iter,
	.mmap		= generic_file_mmap,
	.splice_read	= generic_file_splice_read,
};

static int bfs_move_block(unsigned long from, unsigned long to,
					struct super_block *sb)
{
	struct buffer_head *bh, *new;

	bh = sb_bread(sb, from);
	if (!bh)
		return -EIO;
	new = sb_getblk(sb, to);
	memcpy(new->b_data, bh->b_data, bh->b_size);
	mark_buffer_dirty(new);
	bforget(bh);
	brelse(new);
	return 0;
}

static int bfs_move_blocks(struct super_block *sb, unsigned long start,
				unsigned long end, unsigned long where)
{
	unsigned long i;

	dprintf("%08lx-%08lx->%08lx\n", start, end, where);
	for (i = start; i <= end; i++)
		if(bfs_move_block(i, where + i, sb)) {
			dprintf("failed to move block %08lx -> %08lx\n", i,
								where + i);
			return -EIO;
		}
	return 0;
}

static int bfs_get_block(struct inode *inode, sector_t block,
			struct buffer_head *bh_result, int create)
{
	unsigned long phys;
	int err;
	struct super_block *sb = inode->i_sb;
	struct bfs_sb_info *info = BFS_SB(sb);
	struct bfs_inode_info *bi = BFS_I(inode);

	phys = bi->i_sblock + block;
	if (!create) {
		if (phys <= bi->i_eblock) {
			dprintf("c=%d, b=%08lx, phys=%09lx (granted)\n",
                                create, (unsigned long)block, phys);
			map_bh(bh_result, sb, phys);
		}
		return 0;
	}

	/*
	 * If the file is not empty and the requested block is within the
	 * range of blocks allocated for this file, we can grant it.
	 */
	if (bi->i_sblock && (phys <= bi->i_eblock)) {
		dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n", 
				create, (unsigned long)block, phys);
		map_bh(bh_result, sb, phys);
		return 0;
	}

	/* The file will be extended, so let's see if there is enough space. */
	if (phys >= info->si_blocks)
		return -ENOSPC;

	/* The rest has to be protected against itself. */
	mutex_lock(&info->bfs_lock);

	/*
	 * If the last data block for this file is the last allocated
	 * block, we can extend the file trivially, without moving it
	 * anywhere.
	 */
	if (bi->i_eblock == info->si_lf_eblk) {
		dprintf("c=%d, b=%08lx, phys=%08lx (simple extension)\n", 
				create, (unsigned long)block, phys);
		map_bh(bh_result, sb, phys);
		info->si_freeb -= phys - bi->i_eblock;
		info->si_lf_eblk = bi->i_eblock = phys;
		mark_inode_dirty(inode);
		err = 0;
		goto out;
	}

	/* Ok, we have to move this entire file to the next free block. */
	phys = info->si_lf_eblk + 1;
	if (phys + block >= info->si_blocks) {
		err = -ENOSPC;
		goto out;
	}

	if (bi->i_sblock) {
		err = bfs_move_blocks(inode->i_sb, bi->i_sblock, 
						bi->i_eblock, phys);
		if (err) {
			dprintf("failed to move ino=%08lx -> fs corruption\n",
								inode->i_ino);
			goto out;
		}
	} else
		err = 0;

	dprintf("c=%d, b=%08lx, phys=%08lx (moved)\n",
                create, (unsigned long)block, phys);
	bi->i_sblock = phys;
	phys += block;
	info->si_lf_eblk = bi->i_eblock = phys;

	/*
	 * This assumes nothing can write the inode back while we are here
	 * and thus update inode->i_blocks! (XXX)
	 */
	info->si_freeb -= bi->i_eblock - bi->i_sblock + 1 - inode->i_blocks;
	mark_inode_dirty(inode);
	map_bh(bh_result, sb, phys);
out:
	mutex_unlock(&info->bfs_lock);
	return err;
}

static int bfs_writepage(struct page *page, struct writeback_control *wbc)
{
	return block_write_full_page(page, bfs_get_block, wbc);
}

static int bfs_readpage(struct file *file, struct page *page)
{
	return block_read_full_page(page, bfs_get_block);
}

static void bfs_write_failed(struct address_space *mapping, loff_t to)
{
	struct inode *inode = mapping->host;

	if (to > inode->i_size)
		truncate_pagecache(inode, inode->i_size);
}

static int bfs_write_begin(struct file *file, struct address_space *mapping,
			loff_t pos, unsigned len, unsigned flags,
			struct page **pagep, void **fsdata)
{
	int ret;

	ret = block_write_begin(mapping, pos, len, flags, pagep,
				bfs_get_block);
	if (unlikely(ret))
		bfs_write_failed(mapping, pos + len);

	return ret;
}

static sector_t bfs_bmap(struct address_space *mapping, sector_t block)
{
	return generic_block_bmap(mapping, block, bfs_get_block);
}

const struct address_space_operations bfs_aops = {
	.readpage	= bfs_readpage,
	.writepage	= bfs_writepage,
	.write_begin	= bfs_write_begin,
	.write_end	= generic_write_end,
	.bmap		= bfs_bmap,
};

const struct inode_operations bfs_file_inops;
2b1d18792a5f27b69ff37f34f43f89f5aa3b'>diff</a>)</td></tr></table>
<div class='commit-subject'>f2fs: add customized migrate_page callback</div><div class='commit-msg'>This patch improves the migration of dirty pages and allows migrating atomic
written pages that F2FS uses in Page Cache. Instead of the fallback releasing
page path, it provides better performance for memory compaction, CMA and other
users of memory page migrating. For dirty pages, there is no need to write back
first when migrating. For an atomic written page before committing, we can
migrate the page and update the related 'inmem_pages' list at the same time.

Signed-off-by: Weichao Guo &lt;guoweichao@huawei.com&gt;
Reviewed-by: Chao Yu &lt;yuchao0@huawei.com&gt;
[Jaegeuk Kim: fix some coding style]
Signed-off-by: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=5b7a487cf32d3a266fea83d590d3226b5ad817a7'>Diffstat</a></div><table summary='diffstat' class='diffstat'>