inode.c

嵌入式系统设计与实例开发实验教材二源码 多线程应用程序设计 串行端口程序设计 AD接口实验 CAN总线通信实验 GPS通信实验 Linux内核移植与编译实验 IC卡读写实验 SD驱动使

/*
 *  linux/fs/ufs/inode.c
 *
 * Copyright (C) 1998
 * Daniel Pirkl <[e-mail]>
 * Charles University, Faculty of Mathematics and Physics
 *
 *  from
 *
 *  linux/fs/ext2/inode.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card ([e-mail])
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/fs/minix/inode.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  Goal-directed block allocation by Stephen Tweedie ([e-mail]), 1993
 *  Big-endian to little-endian byte-swapping/bitmaps by
 *        David S. Miller ([e-mail]), 1995
 */

#include <asm/uaccess.h>
#include <asm/system.h>

#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/ufs_fs.h>
#include <linux/sched.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/locks.h>
#include <linux/mm.h>
#include <linux/smp_lock.h>

#include "swab.h"
#include "util.h"

#undef UFS_INODE_DEBUG
#undef UFS_INODE_DEBUG_MORE

#ifdef UFS_INODE_DEBUG
#define UFSD(x) printk("(%s, %d), %s: ", __FILE__, __LINE__, __FUNCTION__); printk x;
#else
#define UFSD(x)
#endif

static int ufs_block_to_path(struct inode *inode, long i_block, int offsets[4])
{
	struct ufs_sb_private_info *uspi = inode->i_sb->u.ufs_sb.s_uspi;
	int ptrs = uspi->s_apb;
	int ptrs_bits = uspi->s_apbshift;
	const long direct_blocks = UFS_NDADDR,
		indirect_blocks = ptrs,
		double_blocks = (1 << (ptrs_bits * 2));
	int n = 0;

	if (i_block < 0) {
		ufs_warning(inode->i_sb, "ufs_block_to_path", "block < 0");
	} else if (i_block < direct_blocks) {
		offsets[n++] = i_block;
	} else if ((i_block -= direct_blocks) < indirect_blocks) {
		offsets[n++] = UFS_IND_BLOCK;
		offsets[n++] = i_block;
	} else if ((i_block -= indirect_blocks) < double_blocks) {
		offsets[n++] = UFS_DIND_BLOCK;
		offsets[n++] = i_block >> ptrs_bits;
		offsets[n++] = i_block & (ptrs - 1);
	} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
		offsets[n++] = UFS_TIND_BLOCK;
		offsets[n++] = i_block >> (ptrs_bits * 2);
		offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
		offsets[n++] = i_block & (ptrs - 1);
	} else {
		ufs_warning(inode->i_sb, "ufs_block_to_path", "block > big");
	}
	return n;
}

int ufs_frag_map(struct inode *inode, int frag)
{
	struct super_block *sb = inode->i_sb;
	struct ufs_sb_private_info *uspi = sb->u.ufs_sb.s_uspi;
	int mask = uspi->s_apbmask>>uspi->s_fpbshift;
	int shift = uspi->s_apbshift-uspi->s_fpbshift;
	int offsets[4], *p;
	int depth = ufs_block_to_path(inode, frag >> uspi->s_fpbshift, offsets);
	int ret = 0;
	u32 block;

	if (depth == 0)
		return 0;

	p = offsets;

	lock_kernel();
	block = inode->u.ufs_i.i_u1.i_data[*p++];
	if (!block)
		goto out;
	while (--depth) {
		struct buffer_head *bh;
		int n = *p++;

		bh = sb_bread(sb, uspi->s_sbbase + fs32_to_cpu(sb, block)+(n>>shift));
		if (!bh)
			goto out;
		block = ((u32*) bh->b_data)[n & mask];
		brelse (bh);
		if (!block)
			goto out;
	}
	ret = uspi->s_sbbase + fs32_to_cpu(sb, block) + (frag & uspi->s_fpbmask);
out:
	unlock_kernel();
	return ret;
}

static struct buffer_head * ufs_inode_getfrag (struct inode *inode,
	unsigned int fragment, unsigned int new_fragment,
	unsigned int required, int *err, int metadata, long *phys, int *new)
{
	struct super_block * sb;
	struct ufs_sb_private_info * uspi;
	struct buffer_head * result;
	unsigned block, blockoff, lastfrag, lastblock, lastblockoff;
	unsigned tmp, goal;
	u32 * p, * p2;

	UFSD(("ENTER, ino %lu, fragment %u, new_fragment %u, required %u\n",
		inode->i_ino, fragment, new_fragment, required))         

	sb = inode->i_sb;
	uspi = sb->u.ufs_sb.s_uspi;
	block = ufs_fragstoblks (fragment);
	blockoff = ufs_fragnum (fragment);
	p = inode->u.ufs_i.i_u1.i_data + block;
	goal = 0;

repeat:
	tmp = fs32_to_cpu(sb, *p);
	lastfrag = inode->u.ufs_i.i_lastfrag;
	if (tmp && fragment < lastfrag) {
		if (metadata) {
			result = sb_getblk(sb, uspi->s_sbbase + tmp + blockoff);
			if (tmp == fs32_to_cpu(sb, *p)) {
				UFSD(("EXIT, result %u\n", tmp + blockoff))
				return result;
			}
			brelse (result);
			goto repeat;
		} else {
			*phys = tmp;
			return NULL;
		}
	}

	lastblock = ufs_fragstoblks (lastfrag);
	lastblockoff = ufs_fragnum (lastfrag);
	/*
	 * We will extend file into new block beyond last allocated block
	 */
	if (lastblock < block) {
		/*
		 * We must reallocate last allocated block
		 */
		if (lastblockoff) {
			p2 = inode->u.ufs_i.i_u1.i_data + lastblock;
			tmp = ufs_new_fragments (inode, p2, lastfrag, 
				fs32_to_cpu(sb, *p2), uspi->s_fpb - lastblockoff, err);
			if (!tmp) {
				if (lastfrag != inode->u.ufs_i.i_lastfrag)
					goto repeat;
				else
					return NULL;
			}
			lastfrag = inode->u.ufs_i.i_lastfrag;
			
		}
		goal = fs32_to_cpu(sb, inode->u.ufs_i.i_u1.i_data[lastblock]) + uspi->s_fpb;
		tmp = ufs_new_fragments (inode, p, fragment - blockoff, 
			goal, required + blockoff, err);
	}
	/*
	 * We will extend last allocated block
	 */
	else if (lastblock == block) {
		tmp = ufs_new_fragments (inode, p, fragment - (blockoff - lastblockoff),
			fs32_to_cpu(sb, *p), required +  (blockoff - lastblockoff), err);
	}
	/*
	 * We will allocate new block before last allocated block
	 */
	else /* (lastblock > block) */ {
		if (lastblock && (tmp = fs32_to_cpu(sb, inode->u.ufs_i.i_u1.i_data[lastblock-1])))
			goal = tmp + uspi->s_fpb;
		tmp = ufs_new_fragments (inode, p, fragment - blockoff, 
			goal, uspi->s_fpb, err);
	}
	if (!tmp) {
		if ((!blockoff && *p) || 
		    (blockoff && lastfrag != inode->u.ufs_i.i_lastfrag))
			goto repeat;
		*err = -ENOSPC;
		return NULL;
	}

	/* The nullification of framgents done in ufs/balloc.c is
	 * something I don't have the stomache to move into here right
	 * now. -DaveM
	 */
	if (metadata) {
		result = sb_getblk(inode->i_sb, tmp + blockoff);
	} else {
		*phys = tmp;
		result = NULL;
		*err = 0;
		*new = 1;
	}

	inode->i_ctime = CURRENT_TIME;
	if (IS_SYNC(inode))
		ufs_sync_inode (inode);
	mark_inode_dirty(inode);
	UFSD(("EXIT, result %u\n", tmp + blockoff))
	return result;
}

static struct buffer_head * ufs_block_getfrag (struct inode *inode,
	struct buffer_head *bh, unsigned int fragment, unsigned int new_fragment, 
	unsigned int blocksize, int * err, int metadata, long *phys, int *new)
{
	struct super_block * sb;
	struct ufs_sb_private_info * uspi;
	struct buffer_head * result;
	unsigned tmp, goal, block, blockoff;
	u32 * p;

	sb = inode->i_sb;
	uspi = sb->u.ufs_sb.s_uspi;
	block = ufs_fragstoblks (fragment);
	blockoff = ufs_fragnum (fragment);

	UFSD(("ENTER, ino %lu, fragment %u, new_fragment %u\n", inode->i_ino, fragment, new_fragment))	

	result = NULL;
	if (!bh)
		goto out;
	if (!buffer_uptodate(bh)) {
		ll_rw_block (READ, 1, &bh);
		wait_on_buffer (bh);
		if (!buffer_uptodate(bh))
			goto out;
	}

	p = (u32 *) bh->b_data + block;
repeat:
	tmp = fs32_to_cpu(sb, *p);
	if (tmp) {
		if (metadata) {
			result = sb_getblk(sb, uspi->s_sbbase + tmp + blockoff);
			if (tmp == fs32_to_cpu(sb, *p))
				goto out;
			brelse (result);
			goto repeat;
		} else {
			*phys = tmp;
			goto out;
		}
	}

	if (block && (tmp = fs32_to_cpu(sb, ((u32*)bh->b_data)[block-1]) + uspi->s_fpb))
		goal = tmp + uspi->s_fpb;
	else
		goal = bh->b_blocknr + uspi->s_fpb;
	tmp = ufs_new_fragments (inode, p, ufs_blknum(new_fragment), goal, uspi->s_fpb, err);
	if (!tmp) {
		if (fs32_to_cpu(sb, *p))
			goto repeat;
		goto out;
	}		

	/* The nullification of framgents done in ufs/balloc.c is
	 * something I don't have the stomache to move into here right
	 * now. -DaveM
	 */
	if (metadata) {
		result = sb_getblk(sb, tmp + blockoff);
	} else {
		*phys = tmp;
		*new = 1;
	}

	mark_buffer_dirty(bh);
	if (IS_SYNC(inode)) {
		ll_rw_block (WRITE, 1, &bh);
		wait_on_buffer (bh);
	}
	inode->i_ctime = CURRENT_TIME;
	mark_inode_dirty(inode);
out:
	brelse (bh);
	UFSD(("EXIT, result %u\n", tmp + blockoff))
	return result;
}

static int ufs_getfrag_block (struct inode *inode, long fragment, struct buffer_head *bh_result, int create)
{
	struct super_block * sb;
	struct ufs_sb_private_info * uspi;
	struct buffer_head * bh;
	int ret, err, new;
	unsigned long ptr, phys;
	
	sb = inode->i_sb;
	uspi = sb->u.ufs_sb.s_uspi;

	if (!create) {
		phys = ufs_frag_map(inode, fragment);
		if (phys) {
			bh_result->b_dev = inode->i_dev;
			bh_result->b_blocknr = phys;
			bh_result->b_state |= (1UL << BH_Mapped);
		}
		return 0;
	}

	err = -EIO;
	new = 0;
	ret = 0;
	bh = NULL;

	lock_kernel();