/* vi: set sw=4 ts=4: *//* * bmap.c --- logical to physical block mapping * * Copyright (C) 1997 Theodore Ts'o. * * %Begin-Header% * This file may be redistributed under the terms of the GNU Public * License. * %End-Header% */#include <stdio.h>#include <string.h>#if HAVE_UNISTD_H#include <unistd.h>#endif#include "ext2_fs.h"#include "ext2fs.h"extern errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino,			     struct ext2_inode *inode,			     char *block_buf, int bmap_flags,			     blk_t block, blk_t *phys_blk);#define inode_bmap(inode, nr) ((inode)->i_block[(nr)])static errcode_t block_ind_bmap(ext2_filsys fs, int flags,					      blk_t ind, char *block_buf,					      int *blocks_alloc,					      blk_t nr, blk_t *ret_blk){	errcode_t	retval;	blk_t		b;	if (!ind) {		if (flags & BMAP_SET)			return EXT2_ET_SET_BMAP_NO_IND;		*ret_blk = 0;		return 0;	}	retval = io_channel_read_blk(fs->io, ind, 1, block_buf);	if (retval)		return retval;	if (flags & BMAP_SET) {		b = *ret_blk;#if BB_BIG_ENDIAN		if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||		    (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))			b = ext2fs_swab32(b);#endif		((blk_t *) block_buf)[nr] = b;		return io_channel_write_blk(fs->io, ind, 1, block_buf);	}	b = ((blk_t *) block_buf)[nr];#if BB_BIG_ENDIAN	if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||	    (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))		b = ext2fs_swab32(b);#endif	if (!b && (flags & BMAP_ALLOC)) {		b = nr ? ((blk_t *) block_buf)[nr-1] : 0;		retval = ext2fs_alloc_block(fs, b,					    block_buf + fs->blocksize, &b);		if (retval)			return retval;#if BB_BIG_ENDIAN		if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||		    (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))			((blk_t *) block_buf)[nr] = ext2fs_swab32(b);		else#endif			((blk_t *) block_buf)[nr] = b;		retval = io_channel_write_blk(fs->io, ind, 1, block_buf);		if (retval)			return retval;		(*blocks_alloc)++;	}	*ret_blk = b;	return 0;}static errcode_t block_dind_bmap(ext2_filsys fs, int flags,					       blk_t dind, char *block_buf,					       int *blocks_alloc,					       blk_t nr, blk_t *ret_blk){	blk_t		b;	errcode_t	retval;	blk_t		addr_per_block;	addr_per_block = (blk_t) fs->blocksize >> 2;	retval = block_ind_bmap(fs, flags & ~BMAP_SET, dind, block_buf,				blocks_alloc, nr / addr_per_block, &b);	if (retval)		return retval;	retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,				nr % addr_per_block, ret_blk);	return retval;}static errcode_t block_tind_bmap(ext2_filsys fs, int flags,					       blk_t tind, char *block_buf,					       int *blocks_alloc,					       blk_t nr, blk_t *ret_blk){	blk_t		b;	errcode_t	retval;	blk_t		addr_per_block;	addr_per_block = (blk_t) fs->blocksize >> 2;	retval = block_dind_bmap(fs, flags & ~BMAP_SET, tind, block_buf,				 blocks_alloc, nr / addr_per_block, &b);	if (retval)		return retval;	retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,				nr % addr_per_block, ret_blk);	return retval;}errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,		      char *block_buf, int bmap_flags, blk_t block,		      blk_t *phys_blk){	struct ext2_inode inode_buf;	blk_t addr_per_block;	blk_t	b;	char	*buf = 0;	errcode_t	retval = 0;	int		blocks_alloc = 0, inode_dirty = 0;	if (!(bmap_flags & BMAP_SET))		*phys_blk = 0;	/* Read inode structure if necessary */	if (!inode) {		retval = ext2fs_read_inode(fs, ino, &inode_buf);		if (retval)			return retval;		inode = &inode_buf;	}	addr_per_block = (blk_t) fs->blocksize >> 2;	if (!block_buf) {		retval = ext2fs_get_mem(fs->blocksize * 2, &buf);		if (retval)			return retval;		block_buf = buf;	}	if (block < EXT2_NDIR_BLOCKS) {		if (bmap_flags & BMAP_SET) {			b = *phys_blk;#if BB_BIG_ENDIAN			if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||			    (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))				b = ext2fs_swab32(b);#endif			inode_bmap(inode, block) = b;			inode_dirty++;			goto done;		}		*phys_blk = inode_bmap(inode, block);		b = block ? inode_bmap(inode, block-1) : 0;		if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) {			retval = ext2fs_alloc_block(fs, b, block_buf, &b);			if (retval)				goto done;			inode_bmap(inode, block) = b;			blocks_alloc++;			*phys_blk = b;		}		goto done;	}	/* Indirect block */	block -= EXT2_NDIR_BLOCKS;	if (block < addr_per_block) {		b = inode_bmap(inode, EXT2_IND_BLOCK);		if (!b) {			if (!(bmap_flags & BMAP_ALLOC)) {				if (bmap_flags & BMAP_SET)					retval = EXT2_ET_SET_BMAP_NO_IND;				goto done;			}			b = inode_bmap(inode, EXT2_IND_BLOCK-1);			retval = ext2fs_alloc_block(fs, b, block_buf, &b);			if (retval)				goto done;			inode_bmap(inode, EXT2_IND_BLOCK) = b;			blocks_alloc++;		}		retval = block_ind_bmap(fs, bmap_flags, b, block_buf,					&blocks_alloc, block, phys_blk);		goto done;	}	/* Doubly indirect block  */	block -= addr_per_block;	if (block < addr_per_block * addr_per_block) {		b = inode_bmap(inode, EXT2_DIND_BLOCK);		if (!b) {			if (!(bmap_flags & BMAP_ALLOC)) {				if (bmap_flags & BMAP_SET)					retval = EXT2_ET_SET_BMAP_NO_IND;				goto done;			}			b = inode_bmap(inode, EXT2_IND_BLOCK);			retval = ext2fs_alloc_block(fs, b, block_buf, &b);			if (retval)				goto done;			inode_bmap(inode, EXT2_DIND_BLOCK) = b;			blocks_alloc++;		}		retval = block_dind_bmap(fs, bmap_flags, b, block_buf,					 &blocks_alloc, block, phys_blk);		goto done;	}	/* Triply indirect block */	block -= addr_per_block * addr_per_block;	b = inode_bmap(inode, EXT2_TIND_BLOCK);	if (!b) {		if (!(bmap_flags & BMAP_ALLOC)) {			if (bmap_flags & BMAP_SET)				retval = EXT2_ET_SET_BMAP_NO_IND;			goto done;		}		b = inode_bmap(inode, EXT2_DIND_BLOCK);		retval = ext2fs_alloc_block(fs, b, block_buf, &b);		if (retval)			goto done;		inode_bmap(inode, EXT2_TIND_BLOCK) = b;		blocks_alloc++;	}	retval = block_tind_bmap(fs, bmap_flags, b, block_buf,				 &blocks_alloc, block, phys_blk);done:	ext2fs_free_mem(&buf);	if ((retval == 0) && (blocks_alloc || inode_dirty)) {		inode->i_blocks += (blocks_alloc * fs->blocksize) / 512;		retval = ext2fs_write_inode(fs, ino, inode);	}	return retval;}