path: root/fs/gfs2/bmap.c

/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2005 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 v.2.
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <asm/semaphore.h>

#include "gfs2.h"
#include "bmap.h"
#include "glock.h"
#include "inode.h"
#include "jdata.h"
#include "meta_io.h"
#include "page.h"
#include "quota.h"
#include "rgrp.h"
#include "trans.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 {
	__u16 mp_list[GFS2_MAX_META_HEIGHT];
};

typedef int (*block_call_t) (struct gfs2_inode *ip, struct buffer_head *dibh,
			     struct buffer_head *bh, uint64_t *top,
			     uint64_t *bottom, unsigned int height,
			     void *data);

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

/**
 * @gfs2_unstuffer_sync - Synchronously unstuff a dinode
 * @ip:
 * @dibh:
 * @block:
 * @private:
 *
 * Cheat and use a metadata buffer instead of a data page.
 *
 * Returns: errno
 */

int gfs2_unstuffer_sync(struct gfs2_inode *ip, struct buffer_head *dibh,
			uint64_t block, void *private)
{
	struct buffer_head *bh;
	int error;

	bh = gfs2_meta_new(ip->i_gl, block);

	gfs2_buffer_copy_tail(bh, 0, dibh, sizeof(struct gfs2_dinode));

	set_buffer_dirty(bh);
	error = sync_dirty_buffer(bh);

	brelse(bh);

	return error;
}

/**
 * gfs2_unstuff_dinode - Unstuff a dinode when the data has grown too big
 * @ip: The GFS2 inode to unstuff
 * @unstuffer: the routine that handles unstuffing a non-zero length file
 * @private: private data for the unstuffer
 *
 * 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, gfs2_unstuffer_t unstuffer,
			void *private)
{
	struct buffer_head *bh, *dibh;
	uint64_t block = 0;
	int journaled = gfs2_is_jdata(ip);
	int error;

	down_write(&ip->i_rw_mutex);

	error = gfs2_meta_inode_buffer(ip, &dibh);
	if (error)
		goto out;
		
	if (ip->i_di.di_size) {
		/* Get a free block, fill it with the stuffed data,
		   and write it out to disk */

		if (journaled) {
			block = gfs2_alloc_meta(ip);

			error = gfs2_jdata_get_buffer(ip, block, 1, &bh);
			if (error)
				goto out_brelse;
			gfs2_buffer_copy_tail(bh,
					      sizeof(struct gfs2_meta_header),
					      dibh, sizeof(struct gfs2_dinode));
			brelse(bh);
		} else {
			block = gfs2_alloc_data(ip);

			error = unstuffer(ip, dibh, block, private);
			if (error)
				goto out_brelse;
		}
	}

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

	gfs2_trans_add_bh(ip->i_gl, dibh);

	gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));

	if (ip->i_di.di_size) {
		*(uint64_t *)(dibh->b_data + sizeof(struct gfs2_dinode)) = cpu_to_be64(block);
		ip->i_di.di_blocks++;
	}

	ip->i_di.di_height = 1;

	gfs2_dinode_out(&ip->i_di, dibh->b_data);

 out_brelse:
	brelse(dibh);

 out:
	up_write(&ip->i_rw_mutex);

	return error;
}

/**
 * calc_tree_height - Calculate the height of a metadata tree
 * @ip: The GFS2 inode
 * @size: The proposed size of the file
 *
 * Work out how tall a metadata tree needs to be in order to accommodate a
 * file of a particular size. If size is less than the current size of
 * the inode, then the current size of the inode is used instead of the
 * supplied one.
 *
 * Returns: the height the t