path: root/fs/gfs2/bmap.c

/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/blkdev.h>
#include <linux/gfs2_ondisk.h>
#include <linux/crc32.h>

#include "gfs2.h"
#include "incore.h"
#include "bmap.h"
#include "glock.h"
#include "inode.h"
#include "meta_io.h"
#include "quota.h"
#include "rgrp.h"
#include "super.h"
#include "trans.h"
#include "dir.h"
#include "util.h"
#include "trace_gfs2.h"

/* This doesn't need to be that large as max 64 bit pointers in a 4k
 * block is 512, so __u16 is fine for that. It saves stack space to
 * keep it small.
 */
struct metapath {
	struct buffer_head *mp_bh[GFS2_MAX_META_HEIGHT];
	__u16 mp_list[GFS2_MAX_META_HEIGHT];
};

struct strip_mine {
	int sm_first;
	unsigned int sm_height;
};

/**
 * gfs2_unstuffer_page - unstuff a stuffed inode into a block cached by a page
 * @ip: the inode
 * @dibh: the dinode buffer
 * @block: the block number that was allocated
 * @page: The (optional) page. This is looked up if @page is NULL
 *
 * Returns: errno
 */

static int gfs2_unstuffer_page(struct gfs2_inode *ip, struct buffer_head *dibh,
			       u64 block, struct page *page)
{
	struct inode *inode = &ip->i_inode;
	struct buffer_head *bh;
	int release = 0;

	if (!page || page->index) {
		page = find_or_create_page(inode->i_mapping, 0, GFP_NOFS);
		if (!page)
			return -ENOMEM;
		release = 1;
	}

	if (!PageUptodate(page)) {
		void *kaddr = kmap(page);
		u64 dsize = i_size_read(inode);
 
		if (dsize > (dibh->b_size - sizeof(struct gfs2_dinode)))
			dsize = dibh->b_size - sizeof(struct gfs2_dinode);

		memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize);
		memset(kaddr + dsize, 0, PAGE_CACHE_SIZE - dsize);
		kunmap(page);

		SetPageUptodate(page);
	}

	if (!page_has_buffers(page))
		create_empty_buffers(page, 1 << inode->i_blkbits,
				     (1 << BH_Uptodate));

	bh = page_buffers(page);

	if (!buffer_mapped(bh))
		map_bh(bh, inode->i_sb, block);

	set_buffer_uptodate(bh);
	if (!gfs2_is_jdata(ip))
		mark_buffer_dirty(bh);
	if (!gfs2_is_writeback(ip))
		gfs2_trans_add_bh(ip->i_gl, bh, 0);

	if (release) {
		unlock_page(page);
		page_cache_release(page);
	}

	return 0;
}

/**
 * gfs2_unstuff_dinode - Unstuff a dinode when the data has grown too big
 * @ip: The GFS2 inode to unstuff
 * @page: The (optional) page. This is looked up if the @page is NULL
 *
 * This routine unstuffs a dinode and returns it to a "normal" state such
 * that the height can be grown in the traditional way.
 *
 * Returns: errno
 */

int gfs2_unstuff_dinode(struct gfs2_inode *ip, struct page *page)
{
	struct buffer_head *bh, *dibh;
	struct gfs2_dinode *di;
	u64 block = 0;
	int isdir = gfs2_is_dir(ip);
	int error;

	down_write(&ip->i_rw_mutex);

	error = gfs2_meta_inode_buffer(ip, &dibh);
	if (error)
		goto out;

	if (i_size_read(&ip->i_inode)) {
		/* Get a free block, fill it with the stuffed data,
		   and write it out to disk */

		unsigned int n = 1;
		error = gfs2_alloc_blocks(ip, &block, &n, 0, NULL);
		if (error)
			goto out_brelse;
		if (isdir) {
			gfs2_trans_add_unrevoke(GFS2_SB(&ip->i_inode), block, 1);
			error = gfs2_dir_get_new_buffer(ip, block, &bh);
			if (error)
				goto out_brelse;
			gfs2_buffer_copy_tail(bh, sizeof(struct gfs2_meta_header),
					      dibh, sizeof(struct gfs2_dinode));
			brelse(bh);
		} else {
			error = gfs2_unstuffer_page(ip, dibh, block, page);
			if (error)
				goto out_brelse;
		}
	}

	/*  Set up the pointer to the new block  */

	gfs2_trans_add_bh(ip->i_gl, dibh, 1);
	di = (struct gfs2_dinode *)dibh->b_data;
	gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));

	if (i_size_read