balloc.c

嵌入式系统设计与实验教材二源码linux内核移植与编译

/*
 *  linux/fs/ufs/balloc.c
 *
 * Copyright (C) 1998
 * Daniel Pirkl <[e-mail]>
 * Charles University, Faculty of Mathematics and Physics
 */

#include <linux/fs.h>
#include <linux/ufs_fs.h>
#include <linux/stat.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/locks.h>
#include <linux/quotaops.h>
#include <asm/bitops.h>
#include <asm/byteorder.h>

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

#undef UFS_BALLOC_DEBUG

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

unsigned ufs_add_fragments (struct inode *, unsigned, unsigned, unsigned, int *);
unsigned ufs_alloc_fragments (struct inode *, unsigned, unsigned, unsigned, int *);
unsigned ufs_alloccg_block (struct inode *, struct ufs_cg_private_info *, unsigned, int *);
unsigned ufs_bitmap_search (struct super_block *, struct ufs_cg_private_info *, unsigned, unsigned);
static unsigned char ufs_fragtable_8fpb[], ufs_fragtable_other[];
void ufs_clusteracct(struct super_block *, struct ufs_cg_private_info *, unsigned, int);

/*
 * Free 'count' fragments from fragment number 'fragment'
 */
void ufs_free_fragments (struct inode * inode, unsigned fragment, unsigned count) {
	struct super_block * sb;
	struct ufs_sb_private_info * uspi;
	struct ufs_super_block_first * usb1;
	struct ufs_cg_private_info * ucpi;
	struct ufs_cylinder_group * ucg;
	unsigned cgno, bit, end_bit, bbase, blkmap, i, blkno, cylno;
	
	sb = inode->i_sb;
	uspi = sb->u.ufs_sb.s_uspi;
	usb1 = ubh_get_usb_first(USPI_UBH);
	
	UFSD(("ENTER, fragment %u, count %u\n", fragment, count))
	
	if (ufs_fragnum(fragment) + count > uspi->s_fpg)
		ufs_error (sb, "ufs_free_fragments", "internal error");
	
	lock_super(sb);
	
	cgno = ufs_dtog(fragment);
	bit = ufs_dtogd(fragment);
	if (cgno >= uspi->s_ncg) {
		ufs_panic (sb, "ufs_free_fragments", "freeing blocks are outside device");
		goto failed;
	}
		
	ucpi = ufs_load_cylinder (sb, cgno);
	if (!ucpi) 
		goto failed;
	ucg = ubh_get_ucg (UCPI_UBH);
	if (!ufs_cg_chkmagic(sb, ucg)) {
		ufs_panic (sb, "ufs_free_fragments", "internal error, bad magic number on cg %u", cgno);
		goto failed;
	}

	end_bit = bit + count;
	bbase = ufs_blknum (bit);
	blkmap = ubh_blkmap (UCPI_UBH, ucpi->c_freeoff, bbase);
	ufs_fragacct (sb, blkmap, ucg->cg_frsum, -1);
	for (i = bit; i < end_bit; i++) {
		if (ubh_isclr (UCPI_UBH, ucpi->c_freeoff, i))
			ubh_setbit (UCPI_UBH, ucpi->c_freeoff, i);
		else ufs_error (sb, "ufs_free_fragments",
			"bit already cleared for fragment %u", i);
	}
	
	DQUOT_FREE_BLOCK (inode, count);

	
	fs32_add(sb, &ucg->cg_cs.cs_nffree, count);
	fs32_add(sb, &usb1->fs_cstotal.cs_nffree, count);
	fs32_add(sb, &sb->fs_cs(cgno).cs_nffree, count);
	blkmap = ubh_blkmap (UCPI_UBH, ucpi->c_freeoff, bbase);
	ufs_fragacct(sb, blkmap, ucg->cg_frsum, 1);

	/*
	 * Trying to reassemble free fragments into block
	 */
	blkno = ufs_fragstoblks (bbase);
	if (ubh_isblockset(UCPI_UBH, ucpi->c_freeoff, blkno)) {
		fs32_sub(sb, &ucg->cg_cs.cs_nffree, uspi->s_fpb);
		fs32_sub(sb, &usb1->fs_cstotal.cs_nffree, uspi->s_fpb);
		fs32_sub(sb, &sb->fs_cs(cgno).cs_nffree, uspi->s_fpb);
		if ((sb->u.ufs_sb.s_flags & UFS_CG_MASK) == UFS_CG_44BSD)
			ufs_clusteracct (sb, ucpi, blkno, 1);
		fs32_add(sb, &ucg->cg_cs.cs_nbfree, 1);
		fs32_add(sb, &usb1->fs_cstotal.cs_nbfree, 1);
		fs32_add(sb, &sb->fs_cs(cgno).cs_nbfree, 1);
		cylno = ufs_cbtocylno (bbase);
		fs16_add(sb, &ubh_cg_blks(ucpi, cylno, ufs_cbtorpos(bbase)), 1);
		fs32_add(sb, &ubh_cg_blktot(ucpi, cylno), 1);
	}
	
	ubh_mark_buffer_dirty (USPI_UBH);
	ubh_mark_buffer_dirty (UCPI_UBH);
	if (sb->s_flags & MS_SYNCHRONOUS) {
		ubh_ll_rw_block (WRITE, 1, (struct ufs_buffer_head **)&ucpi);
		ubh_wait_on_buffer (UCPI_UBH);
	}
	sb->s_dirt = 1;
	
	unlock_super (sb);
	UFSD(("EXIT\n"))
	return;

failed:
	unlock_super (sb);
	UFSD(("EXIT (FAILED)\n"))
	return;
}

/*
 * Free 'count' fragments from fragment number 'fragment' (free whole blocks)
 */
void ufs_free_blocks (struct inode * inode, unsigned fragment, unsigned count) {
	struct super_block * sb;
	struct ufs_sb_private_info * uspi;
	struct ufs_super_block_first * usb1;
	struct ufs_cg_private_info * ucpi;
	struct ufs_cylinder_group * ucg;
	unsigned overflow, cgno, bit, end_bit, blkno, i, cylno;
	
	sb = inode->i_sb;
	uspi = sb->u.ufs_sb.s_uspi;
	usb1 = ubh_get_usb_first(USPI_UBH);

	UFSD(("ENTER, fragment %u, count %u\n", fragment, count))
	
	if ((fragment & uspi->s_fpbmask) || (count & uspi->s_fpbmask)) {
		ufs_error (sb, "ufs_free_blocks", "internal error, "
			"fragment %u, count %u\n", fragment, count);
		goto failed;
	}

	lock_super(sb);
	
do_more:
	overflow = 0;
	cgno = ufs_dtog (fragment);
	bit = ufs_dtogd (fragment);
	if (cgno >= uspi->s_ncg) {
		ufs_panic (sb, "ufs_free_blocks", "freeing blocks are outside device");
		goto failed;
	}
	end_bit = bit + count;
	if (end_bit > uspi->s_fpg) {
		overflow = bit + count - uspi->s_fpg;
		count -= overflow;
		end_bit -= overflow;
	}

	ucpi = ufs_load_cylinder (sb, cgno);
	if (!ucpi) 
		goto failed;
	ucg = ubh_get_ucg (UCPI_UBH);
	if (!ufs_cg_chkmagic(sb, ucg)) {
		ufs_panic (sb, "ufs_free_blocks", "internal error, bad magic number on cg %u", cgno);
		goto failed;
	}

	for (i = bit; i < end_bit; i += uspi->s_fpb) {
		blkno = ufs_fragstoblks(i);
		if (ubh_isblockset(UCPI_UBH, ucpi->c_freeoff, blkno)) {
			ufs_error(sb, "ufs_free_blocks", "freeing free fragment");
		}
		ubh_setblock(UCPI_UBH, ucpi->c_freeoff, blkno);
		if ((sb->u.ufs_sb.s_flags & UFS_CG_MASK) == UFS_CG_44BSD)
			ufs_clusteracct (sb, ucpi, blkno, 1);
		DQUOT_FREE_BLOCK(inode, uspi->s_fpb);

		fs32_add(sb, &ucg->cg_cs.cs_nbfree, 1);
		fs32_add(sb, &usb1->fs_cstotal.cs_nbfree, 1);
		fs32_add(sb, &sb->fs_cs(cgno).cs_nbfree, 1);
		cylno = ufs_cbtocylno(i);
		fs16_add(sb, &ubh_cg_blks(ucpi, cylno, ufs_cbtorpos(i)), 1);
		fs32_add(sb, &ubh_cg_blktot(ucpi, cylno), 1);
	}

	ubh_mark_buffer_dirty (USPI_UBH);
	ubh_mark_buffer_dirty (UCPI_UBH);
	if (sb->s_flags & MS_SYNCHRONOUS) {
		ubh_ll_rw_block (WRITE, 1, (struct ufs_buffer_head **)&ucpi);
		ubh_wait_on_buffer (UCPI_UBH);
	}

	if (overflow) {
		fragment += count;
		count = overflow;
		goto do_more;
	}

	sb->s_dirt = 1;
	unlock_super (sb);
	UFSD(("EXIT\n"))
	return;

failed:
	unlock_super (sb);
	UFSD(("EXIT (FAILED)\n"))
	return;
}



#define NULLIFY_FRAGMENTS \
	for (i = oldcount; i < newcount; i++) { \
		bh = sb_getblk(sb, result + i); \
		memset (bh->b_data, 0, sb->s_blocksize); \
		mark_buffer_uptodate(bh, 1); \
		mark_buffer_dirty (bh); \
		if (IS_SYNC(inode)) { \
			ll_rw_block (WRITE, 1, &bh); \
			wait_on_buffer (bh); \
		} \
		brelse (bh); \
	}

unsigned ufs_new_fragments (struct inode * inode, u32 * p, unsigned fragment,
	unsigned goal, unsigned count, int * err )
{
	struct super_block * sb;
	struct ufs_sb_private_info * uspi;
	struct ufs_super_block_first * usb1;
	struct buffer_head * bh;
	unsigned cgno, oldcount, newcount, tmp, request, i, result;
	
	UFSD(("ENTER, ino %lu, fragment %u, goal %u, count %u\n", inode->i_ino, fragment, goal, count))
	
	sb = inode->i_sb;
	uspi = sb->u.ufs_sb.s_uspi;
	usb1 = ubh_get_usb_first(USPI_UBH);
	*err = -ENOSPC;

	lock_super (sb);
	
	tmp = fs32_to_cpu(sb, *p);
	if (count + ufs_fragnum(fragment) > uspi->s_fpb) {
		ufs_warning (sb, "ufs_new_fragments", "internal warning"
			" fragment %u, count %u", fragment, count);
		count = uspi->s_fpb - ufs_fragnum(fragment); 
	}
	oldcount = ufs_fragnum (fragment);
	newcount = oldcount + count;

	/*
	 * Somebody else has just allocated our fragments
	 */
	if (oldcount) {
		if (!tmp) {
			ufs_error (sb, "ufs_new_fragments", "internal error, "
				"fragment %u, tmp %u\n", fragment, tmp);
			unlock_super (sb);
			return (unsigned)-1;
		}
		if (fragment < inode->u.ufs_i.i_lastfrag) {
			UFSD(("EXIT (ALREADY ALLOCATED)\n"))
			unlock_super (sb);
			return 0;
		}
	}
	else {
		if (tmp) {
			UFSD(("EXIT (ALREADY ALLOCATED)\n"))
			unlock_super(sb);
			return 0;
		}
	}

	/*
	 * There is not enough space for user on the device
	 */
	if (!capable(CAP_SYS_RESOURCE) && ufs_freespace(usb1, UFS_MINFREE) <= 0) {
		unlock_super (sb);
		UFSD(("EXIT (FAILED)\n"))
		return 0;
	}

	if (goal >= uspi->s_size) 
		goal = 0;
	if (goal == 0) 
		cgno = ufs_inotocg (inode->i_ino);
	else
		cgno = ufs_dtog (goal);
	 
	/*
	 * allocate new fragment
	 */
	if (oldcount == 0) {
		result = ufs_alloc_fragments (inode, cgno, goal, count, err);
		if (result) {
			*p = cpu_to_fs32(sb, result);
			*err = 0;
			inode->i_blocks += count << uspi->s_nspfshift;
			inode->u.ufs_i.i_lastfrag = max_t(u32, inode->u.ufs_i.i_lastfrag, fragment + count);
			NULLIFY_FRAGMENTS
		}
		unlock_super(sb);
		UFSD(("EXIT, result %u\n", result))
		return result;
	}

	/*
	 * resize block
	 */
	result = ufs_add_fragments (inode, tmp, oldcount, newcount, err);
	if (result) {
		*err = 0;
		inode->i_blocks += count << uspi->s_nspfshift;
		inode->u.ufs_i.i_lastfrag = max_t(u32, inode->u.ufs_i.i_lastfrag, fragment + count);
		NULLIFY_FRAGMENTS
		unlock_super(sb);
		UFSD(("EXIT, result %u\n", result))
		return result;
	}

	/*
	 * allocate new block and move data
	 */
	switch (fs32_to_cpu(sb, usb1->fs_optim)) {
	    case UFS_OPTSPACE:
		request = newcount;
		if (uspi->s_minfree < 5 || fs32_to_cpu(sb, usb1->fs_cstotal.cs_nffree) 
		    > uspi->s_dsize * uspi->s_minfree / (2 * 100) )
			break;
		usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME);
		break;
	    default:
		usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME);
	
	    case UFS_OPTTIME:
		request = uspi->s_fpb;
		if (fs32_to_cpu(sb, usb1->fs_cstotal.cs_nffree) < uspi->s_dsize *
		    (uspi->s_minfree - 2) / 100)
			break;
		usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME);
		break;
	}
	result = ufs_alloc_fragments (inode, cgno, goal, request, err);
	if (result) {
		for (i = 0; i < oldcount; i++) {
			bh = sb_bread(sb, tmp + i);
			if(bh)
			{
				mark_buffer_clean (bh);
				bh->b_blocknr = result + i;
				mark_buffer_dirty (bh);
				if (IS_SYNC(inode)) {
					ll_rw_block (WRITE, 1, &bh);
					wait_on_buffer (bh);
				}
				brelse (bh);
			}
			else
			{
				printk(KERN_ERR "ufs_new_fragments: bread fail\n");
				return 0;
			}
		}
		*p = cpu_to_fs32(sb, result);
		*err = 0;
		inode->i_blocks += count << uspi->s_nspfshift;
		inode->u.ufs_i.i_lastfrag = max_t(u32, inode->u.ufs_i.i_lastfrag, fragment + count);
		NULLIFY_FRAGMENTS
		unlock_super(sb);
		if (newcount < request)
			ufs_free_fragments (inode, result + newcount, request - newcount);
		ufs_free_fragments (inode, tmp, oldcount);
		UFSD(("EXIT, result %u\n", result))
		return result;
	}

	unlock_super(sb);
	UFSD(("EXIT (FAILED)\n"))
	return 0;
}		

unsigned ufs_add_fragments (struct inode * inode, unsigned fragment,
	unsigned oldcount, unsigned newcount, int * err)
{
	struct super_block * sb;
	struct ufs_sb_private_info * uspi;
	struct ufs_super_block_first * usb1;
	struct ufs_cg_private_info * ucpi;
	struct ufs_cylinder_group * ucg;
	unsigned cgno, fragno, fragoff, count, fragsize, i;
	
	UFSD(("ENTER, fragment %u, oldcount %u, newcount %u\n", fragment, oldcount, newcount))
	
	sb = inode->i_sb;