namei.c

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

				nameptr = fi->fileIdent + liu;
			else
			{
				int poffset;	/* Unpaded ending offset */
	
				poffset = fibh->soffset + sizeof(struct FileIdentDesc) + liu + lfi;
	
				if (poffset >= lfi)
					nameptr = (char *)(fibh->ebh->b_data + poffset - lfi);
				else
				{
					nameptr = fname;
					memcpy(nameptr, fi->fileIdent + liu, lfi - poffset);
					memcpy(nameptr + lfi - poffset, fibh->ebh->b_data, poffset);
				}
			}
	
			if ( (cfi->fileCharacteristics & FILE_DELETED) != 0 )
			{
				if (((sizeof(struct FileIdentDesc) + liu + lfi + 3) & ~3) == nfidlen)
				{
					udf_release_data(bh);
					cfi->descTag.tagSerialNum = cpu_to_le16(1);
					cfi->fileVersionNum = cpu_to_le16(1);
					cfi->fileCharacteristics = 0;
					cfi->lengthFileIdent = namelen;
					cfi->lengthOfImpUse = cpu_to_le16(0);
					if (!udf_write_fi(dir, cfi, fi, fibh, NULL, name))
						return fi;
					else
					{
						*err = -EIO;
						return NULL;
					}
				}
			}

			if (!lfi || !dentry)
				continue;

			if ((flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi)) &&
				udf_match(flen, fname, &(dentry->d_name)))
			{
				if (fibh->sbh != fibh->ebh)
					udf_release_data(fibh->ebh);
				udf_release_data(fibh->sbh);
				udf_release_data(bh);
				*err = -EEXIST;
				return NULL;
			}
		}
	}
	else
	{
		block = udf_get_lb_pblock(dir->i_sb, UDF_I_LOCATION(dir), 0);
		if (UDF_I_ALLOCTYPE(dir) == ICB_FLAG_AD_IN_ICB)
		{
			fibh->sbh = fibh->ebh = udf_tread(dir->i_sb, block);
			fibh->soffset = fibh->eoffset = udf_file_entry_alloc_offset(dir);
		}
		else
		{
			fibh->sbh = fibh->ebh = NULL;
			fibh->soffset = fibh->eoffset = sb->s_blocksize;
		}
	}

	f_pos += nfidlen;

	if (UDF_I_ALLOCTYPE(dir) == ICB_FLAG_AD_IN_ICB &&
		sb->s_blocksize - fibh->eoffset < nfidlen)
	{
		udf_release_data(bh);
		bh = NULL;
		fibh->soffset -= udf_ext0_offset(dir);
		fibh->eoffset -= udf_ext0_offset(dir);
		f_pos -= (udf_ext0_offset(dir) >> 2);
		if (fibh->sbh != fibh->ebh)
			udf_release_data(fibh->ebh);
		udf_release_data(fibh->sbh);
		if (!(fibh->sbh = fibh->ebh = udf_expand_dir_adinicb(dir, &block, err)))
			return NULL;
		bloc = UDF_I_LOCATION(dir);
		eloc.logicalBlockNum = block;
		eloc.partitionReferenceNum = UDF_I_LOCATION(dir).partitionReferenceNum;
		elen = dir->i_sb->s_blocksize;
		extoffset = udf_file_entry_alloc_offset(dir);
		if (UDF_I_ALLOCTYPE(dir) == ICB_FLAG_AD_SHORT)
			extoffset += sizeof(short_ad);
		else if (UDF_I_ALLOCTYPE(dir) == ICB_FLAG_AD_LONG)
			extoffset += sizeof(long_ad);
	}

	if (sb->s_blocksize - fibh->eoffset >= nfidlen)
	{
		fibh->soffset = fibh->eoffset;
		fibh->eoffset += nfidlen;
		if (fibh->sbh != fibh->ebh)
		{
			udf_release_data(fibh->sbh);
			fibh->sbh = fibh->ebh;
		}

		if (UDF_I_ALLOCTYPE(dir) != ICB_FLAG_AD_IN_ICB)
			block = eloc.logicalBlockNum + ((elen - 1) >>
				dir->i_sb->s_blocksize_bits);
		else
			block = UDF_I_LOCATION(dir).logicalBlockNum;
				
		fi = (struct FileIdentDesc *)(fibh->sbh->b_data + fibh->soffset);
	}
	else
	{
		fibh->soffset = fibh->eoffset - sb->s_blocksize;
		fibh->eoffset += nfidlen - sb->s_blocksize;
		if (fibh->sbh != fibh->ebh)
		{
			udf_release_data(fibh->sbh);
			fibh->sbh = fibh->ebh;
		}

		block = eloc.logicalBlockNum + ((elen - 1) >>
			dir->i_sb->s_blocksize_bits);

		if (!(fibh->ebh = udf_bread(dir, f_pos >> (dir->i_sb->s_blocksize_bits - 2), 1, err)))
		{
			udf_release_data(bh);
			udf_release_data(fibh->sbh);
			return NULL;
		}

		if (!(fibh->soffset))
		{
			if (udf_next_aext(dir, &bloc, &extoffset, &eloc, &elen, &bh, 1) ==
				EXTENT_RECORDED_ALLOCATED)
			{
				block = eloc.logicalBlockNum + ((elen - 1) >>
					dir->i_sb->s_blocksize_bits);
			}
			else
				block ++;

			udf_release_data(fibh->sbh);
			fibh->sbh = fibh->ebh;
			fi = (struct FileIdentDesc *)(fibh->sbh->b_data);
		}
		else
		{
			fi = (struct FileIdentDesc *)
				(fibh->sbh->b_data + sb->s_blocksize + fibh->soffset);
		}
	}

	memset(cfi, 0, sizeof(struct FileIdentDesc));
	udf_new_tag((char *)cfi, TID_FILE_IDENT_DESC, 2, 1, block, sizeof(tag));
	cfi->fileVersionNum = cpu_to_le16(1);
	cfi->lengthFileIdent = namelen;
	cfi->lengthOfImpUse = cpu_to_le16(0);
	if (!udf_write_fi(dir, cfi, fi, fibh, NULL, name))
	{
		udf_release_data(bh);
		dir->i_size += nfidlen;
		if (UDF_I_ALLOCTYPE(dir) == ICB_FLAG_AD_IN_ICB)
			UDF_I_LENALLOC(dir) += nfidlen;
		dir->i_version = ++event;
		mark_inode_dirty(dir);
		return fi;
	}
	else
	{
		udf_release_data(bh);
		if (fibh->sbh != fibh->ebh)
			udf_release_data(fibh->ebh);
		udf_release_data(fibh->sbh);
		*err = -EIO;
		return NULL;
	}
}

static int udf_delete_entry(struct inode *inode, struct FileIdentDesc *fi,
	struct udf_fileident_bh *fibh, struct FileIdentDesc *cfi)
{
	cfi->fileCharacteristics |= FILE_DELETED;
	if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT))
		memset(&(cfi->icb), 0x00, sizeof(long_ad));
	return udf_write_fi(inode, cfi, fi, fibh, NULL, NULL);
}

static int udf_create(struct inode *dir, struct dentry *dentry, int mode)
{
	struct udf_fileident_bh fibh;
	struct inode *inode;
	struct FileIdentDesc cfi, *fi;
	int err;

	inode = udf_new_inode(dir, mode, &err);
	if (!inode)
		return err;

	if (UDF_I_ALLOCTYPE(inode) == ICB_FLAG_AD_IN_ICB)
		inode->i_data.a_ops = &udf_adinicb_aops;
	else
		inode->i_data.a_ops = &udf_aops;
	inode->i_op = &udf_file_inode_operations;
	inode->i_fop = &udf_file_operations;
	inode->i_mode = mode;
	mark_inode_dirty(inode);

	if (!(fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err)))
	{
		inode->i_nlink --;
		mark_inode_dirty(inode);
		iput(inode);
		return err;
	}
	cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
	cfi.icb.extLocation = cpu_to_lelb(UDF_I_LOCATION(inode));
	*(Uint32 *)((struct ADImpUse *)cfi.icb.impUse)->impUse =
		cpu_to_le32(UDF_I_UNIQUE(inode) & 0x00000000FFFFFFFFUL);
	udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
	if (UDF_I_ALLOCTYPE(dir) == ICB_FLAG_AD_IN_ICB)
	{
		mark_inode_dirty(dir);
		dir->i_version = ++event;
	}
	if (fibh.sbh != fibh.ebh)
		udf_release_data(fibh.ebh);
	udf_release_data(fibh.sbh);
	d_instantiate(dentry, inode);
	return 0;
}

static int udf_mknod(struct inode * dir, struct dentry * dentry, int mode, int rdev)
{
	struct inode * inode;
	struct udf_fileident_bh fibh;
	int err;
	struct FileIdentDesc cfi, *fi;

	err = -EIO;
	inode = udf_new_inode(dir, mode, &err);
	if (!inode)
		goto out;

	inode->i_uid = current->fsuid;
	init_special_inode(inode, mode, rdev);
	if (!(fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err)))
	{
		inode->i_nlink --;
		mark_inode_dirty(inode);
		iput(inode);
		return err;
	}
	cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
	cfi.icb.extLocation = cpu_to_lelb(UDF_I_LOCATION(inode));
	*(Uint32 *)((struct ADImpUse *)cfi.icb.impUse)->impUse =
		cpu_to_le32(UDF_I_UNIQUE(inode) & 0x00000000FFFFFFFFUL);
	udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
	if (UDF_I_ALLOCTYPE(dir) == ICB_FLAG_AD_IN_ICB)
	{
		mark_inode_dirty(dir);
		dir->i_version = ++event;
	}
	mark_inode_dirty(inode);

	if (fibh.sbh != fibh.ebh)
		udf_release_data(fibh.ebh);
	udf_release_data(fibh.sbh);
	d_instantiate(dentry, inode);
	err = 0;
out:
	return err;
}

static int udf_mkdir(struct inode * dir, struct dentry * dentry, int mode)
{
	struct inode * inode;
	struct udf_fileident_bh fibh;
	int err;
	struct FileIdentDesc cfi, *fi;

	err = -EMLINK;
	if (dir->i_nlink >= (256<<sizeof(dir->i_nlink))-1)
		goto out;

	err = -EIO;
	inode = udf_new_inode(dir, S_IFDIR, &err);
	if (!inode)
		goto out;

	inode->i_op = &udf_dir_inode_operations;
	inode->i_fop = &udf_dir_operations;
	if (!(fi = udf_add_entry(inode, NULL, &fibh, &cfi, &err)))
	{
		inode->i_nlink--;
		mark_inode_dirty(inode);
		iput(inode);
		goto out;
	}
	inode->i_nlink = 2;
	cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
	cfi.icb.extLocation = cpu_to_lelb(UDF_I_LOCATION(dir));
	*(Uint32 *)((struct ADImpUse *)cfi.icb.impUse)->impUse =
		cpu_to_le32(UDF_I_UNIQUE(dir) & 0x00000000FFFFFFFFUL);
	cfi.fileCharacteristics = FILE_DIRECTORY | FILE_PARENT;
	udf_write_fi(inode, &cfi, fi, &fibh, NULL, NULL);
	udf_release_data(fibh.sbh);
	inode->i_mode = S_IFDIR | mode;
	if (dir->i_mode & S_ISGID)
		inode->i_mode |= S_ISGID;
	mark_inode_dirty(inode);

	if (!(fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err)))
	{
		inode->i_nlink = 0;
		mark_inode_dirty(inode);
		iput(inode);
		goto out;
	}
	cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
	cfi.icb.extLocation = cpu_to_lelb(UDF_I_LOCATION(inode));
	*(Uint32 *)((struct ADImpUse *)cfi.icb.impUse)->impUse =
		cpu_to_le32(UDF_I_UNIQUE(inode) & 0x00000000FFFFFFFFUL);
	cfi.fileCharacteristics |= FILE_DIRECTORY;
	udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
	dir->i_version = ++event;
	dir->i_nlink++;
	mark_inode_dirty(dir);
	d_instantiate(dentry, inode);
	if (fibh.sbh != fibh.ebh)
		udf_release_data(fibh.ebh);
	udf_release_data(fibh.sbh);
	err = 0;
out:
	return err;
}

static int empty_dir(struct inode *dir)
{
	struct FileIdentDesc *fi, cfi;
	struct udf_fileident_bh fibh;
	loff_t f_pos;
	loff_t size = (udf_ext0_offset(dir) + dir->i_size) >> 2;
	int block;
	lb_addr bloc, eloc;
	Uint32 extoffset, elen, offset;
	struct buffer_head *bh = NULL;

	f_pos = (udf_ext0_offset(dir) >> 2);

	fibh.soffset = fibh.eoffset = (f_pos & ((dir->i_sb->s_blocksize - 1) >> 2)) << 2;
	if (inode_bmap(dir, f_pos >> (dir->i_sb->s_blocksize_bits - 2),
		&bloc, &extoffset, &eloc, &elen, &offset, &bh) == EXTENT_RECORDED_ALLOCATED)
	{
		offset >>= dir->i_sb->s_blocksize_bits;
		block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
		if ((++offset << dir->i_sb->s_blocksize_bits) < elen)
		{
			if (UDF_I_ALLOCTYPE(dir) == ICB_FLAG_AD_SHORT)
				extoffset -= sizeof(short_ad);
			else if (UDF_I_ALLOCTYPE(dir) == ICB_FLAG_AD_LONG)
				extoffset -= sizeof(long_ad);
		}
		else
			offset = 0;
	}
	else
	{
		udf_release_data(bh);
		return 0;
	}

	if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block)))
		return 0;

	while ( (f_pos < size) )
	{
		fi = udf_fileident_read(dir, &f_pos, &fibh, &cfi, &bloc, &extoffset, &eloc, &elen, &offset, &bh);

		if (!fi)
		{
			if (fibh.sbh != fibh.ebh)
				udf_release_data(fibh.ebh);
			udf_release_data(fibh.sbh);
			udf_release_data(bh);
			return 0;
		}

		if (cfi.lengthFileIdent && (cfi.fileCharacteristics & FILE_DELETED) == 0)
		{
			udf_release_data(bh);
			return 0;
		}
	}
	if (fibh.sbh != fibh.ebh)
		udf_release_data(fibh.ebh);
	udf_release_data(fibh.sbh);
	udf_release_data(bh);
	return 1;
}

static int udf_rmdir(struct inode * dir, struct dentry * dentry)
{
	int retval;
	struct inode * inode = dentry->d_inode;
	struct udf_fileident_bh fibh;
	struct FileIdentDesc *fi, cfi;

	retval = -ENOENT;
	fi = udf_find_entry(dir, dentry, &fibh, &cfi);
	if (!fi)
		goto out;

	retval = -EIO;
	if (udf_get_lb_pblock(dir->i_sb, lelb_to_cpu(cfi.icb.extLocation), 0) != inode->i_ino)
		goto end_rmdir;
	retval = -ENOTEMPTY;
	if (!empty_dir(inode))
		goto end_rmdir;
	retval = udf_delete_entry(dir, fi, &fibh, &cfi);
	dir->i_version = ++event;
	if (retval)
		goto end_rmdir;
	if (inode->i_nlink != 2)
		udf_warning(inode->i_sb, "udf_rmdir",
			"empty directory has nlink != 2 (%d)",
			inode->i_nlink);
	inode->i_version = ++event;
	inode->i_nlink = 0;
	inode->i_size = 0;
	mark_inode_dirty(inode);
	dir->i_nlink --;
	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;