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

	UDF_I_UCTIME(inode) = UDF_I_UCTIME(dir) = UDF_I_UMTIME(dir) = CURRENT_UTIME;
	mark_inode_dirty(dir);

end_rmdir:
	if (fibh.sbh != fibh.ebh)
		udf_release_data(fibh.ebh);
	udf_release_data(fibh.sbh);
out:
	return retval;
}

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

	if (!inode->i_nlink)
	{
		udf_debug("Deleting nonexistent file (%lu), %d\n",
			inode->i_ino, inode->i_nlink);
		inode->i_nlink = 1;
	}
	retval = udf_delete_entry(dir, fi, &fibh, &cfi);
	if (retval)
		goto end_unlink;
	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
	UDF_I_UCTIME(dir) = UDF_I_UMTIME(dir) = CURRENT_UTIME;
	mark_inode_dirty(dir);
	inode->i_nlink--;
	mark_inode_dirty(inode);
	inode->i_ctime = dir->i_ctime;
	retval = 0;

end_unlink:
	if (fibh.sbh != fibh.ebh)
		udf_release_data(fibh.ebh);
	udf_release_data(fibh.sbh);
out:
	return retval;
}

static int udf_symlink(struct inode * dir, struct dentry * dentry, const char * symname)
{
	struct inode * inode;
	struct PathComponent *pc;
	char *compstart;
	struct udf_fileident_bh fibh;
	struct buffer_head *bh = NULL;
	int eoffset, elen = 0;
	struct FileIdentDesc *fi;
	struct FileIdentDesc cfi;
	char *ea;
	int err;
	int block;

	if (!(inode = udf_new_inode(dir, S_IFLNK, &err)))
		goto out;

	inode->i_mode = S_IFLNK | S_IRWXUGO;
	inode->i_data.a_ops = &udf_symlink_aops;
	inode->i_op = &page_symlink_inode_operations;

	if (UDF_I_ALLOCTYPE(inode) != ICB_FLAG_AD_IN_ICB)
	{
		struct buffer_head *bh = NULL;
		lb_addr bloc, eloc;
		Uint32 elen, extoffset;

		block = udf_new_block(inode->i_sb, inode,
			UDF_I_LOCATION(inode).partitionReferenceNum,
			UDF_I_LOCATION(inode).logicalBlockNum, &err);
		if (!block)
			goto out_no_entry;
		bloc = UDF_I_LOCATION(inode);
		eloc.logicalBlockNum = block;
		eloc.partitionReferenceNum = UDF_I_LOCATION(inode).partitionReferenceNum;
		elen = inode->i_sb->s_blocksize;
		UDF_I_LENEXTENTS(inode) = elen;
		extoffset = udf_file_entry_alloc_offset(inode);
		udf_add_aext(inode, &bloc, &extoffset, eloc, elen, &bh, 0);
		udf_release_data(bh);

		block = udf_get_pblock(inode->i_sb, block,
			UDF_I_LOCATION(inode).partitionReferenceNum, 0);
		bh = udf_tread(inode->i_sb, block);
		lock_buffer(bh);
		memset(bh->b_data, 0x00, inode->i_sb->s_blocksize);
		mark_buffer_uptodate(bh, 1);
		unlock_buffer(bh);
		mark_buffer_dirty_inode(bh, inode);
	}
	else
	{
		block = udf_get_lb_pblock(inode->i_sb, UDF_I_LOCATION(inode), 0);
		bh = udf_tread(inode->i_sb, block);
	}
	ea = bh->b_data + udf_ext0_offset(inode);

	eoffset = inode->i_sb->s_blocksize - udf_ext0_offset(inode);
	pc = (struct PathComponent *)ea;

	if (*symname == '/')
	{
		do
		{
			symname++;
		} while (*symname == '/');

		pc->componentType = 1;
		pc->lengthComponentIdent = 0;
		pc->componentFileVersionNum = 0;
		pc += sizeof(struct PathComponent);
		elen += sizeof(struct PathComponent);
	}

	err = -ENAMETOOLONG;

	while (*symname)
	{
		if (elen + sizeof(struct PathComponent) > eoffset)
			goto out_no_entry;

		pc = (struct PathComponent *)(ea + elen);

		compstart = (char *)symname;

		do
		{
			symname++;
		} while (*symname && *symname != '/');

		pc->componentType = 5;
		pc->lengthComponentIdent = 0;
		pc->componentFileVersionNum = 0;
		if (pc->componentIdent[0] == '.')
		{
			if (pc->lengthComponentIdent == 1)
				pc->componentType = 4;
			else if (pc->lengthComponentIdent == 2 && pc->componentIdent[1] == '.')
				pc->componentType = 3;
		}

		if (pc->componentType == 5)
		{
			if (elen + sizeof(struct PathComponent) + symname - compstart > eoffset)
				goto out_no_entry;
			else
				pc->lengthComponentIdent = symname - compstart;

			memcpy(pc->componentIdent, compstart, pc->lengthComponentIdent);
		}

		elen += sizeof(struct PathComponent) + pc->lengthComponentIdent;

		if (*symname)
		{
			do
			{
				symname++;
			} while (*symname == '/');
		}
	}

	udf_release_data(bh);
	inode->i_size = elen;
	if (UDF_I_ALLOCTYPE(inode) == ICB_FLAG_AD_IN_ICB)
		UDF_I_LENALLOC(inode) = inode->i_size;
	mark_inode_dirty(inode);

	if (!(fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err)))
		goto out_no_entry;
	cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
	cfi.icb.extLocation = cpu_to_lelb(UDF_I_LOCATION(inode));
	if (UDF_SB_LVIDBH(inode->i_sb))
	{
		struct LogicalVolHeaderDesc *lvhd;
		Uint64 uniqueID;
		lvhd = (struct LogicalVolHeaderDesc *)(UDF_SB_LVID(inode->i_sb)->logicalVolContentsUse);
		uniqueID = le64_to_cpu(lvhd->uniqueID);
		*(Uint32 *)((struct ADImpUse *)cfi.icb.impUse)->impUse =
			cpu_to_le32(uniqueID & 0x00000000FFFFFFFFUL);
		if (!(++uniqueID & 0x00000000FFFFFFFFUL))
			uniqueID += 16;
		lvhd->uniqueID = cpu_to_le64(uniqueID);
		mark_buffer_dirty(UDF_SB_LVIDBH(inode->i_sb));
	}
	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);
	err = 0;

out:
	return err;

out_no_entry:
	inode->i_nlink--;
	mark_inode_dirty(inode);
	iput(inode);
	goto out;
}

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

	if (S_ISDIR(inode->i_mode))
		return -EPERM;

	if (inode->i_nlink >= (256<<sizeof(inode->i_nlink))-1)
		return -EMLINK;

	if (!(fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err)))
		return err;
	cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
	cfi.icb.extLocation = cpu_to_lelb(UDF_I_LOCATION(inode));
	if (UDF_SB_LVIDBH(inode->i_sb))
	{
		struct LogicalVolHeaderDesc *lvhd;
		Uint64 uniqueID;
		lvhd = (struct LogicalVolHeaderDesc *)(UDF_SB_LVID(inode->i_sb)->logicalVolContentsUse);
		uniqueID = le64_to_cpu(lvhd->uniqueID);
		*(Uint32 *)((struct ADImpUse *)cfi.icb.impUse)->impUse =
			cpu_to_le32(uniqueID & 0x00000000FFFFFFFFUL);
		if (!(++uniqueID & 0x00000000FFFFFFFFUL))
			uniqueID += 16;
		lvhd->uniqueID = cpu_to_le64(uniqueID);
		mark_buffer_dirty(UDF_SB_LVIDBH(inode->i_sb));
	}
	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);
	inode->i_nlink ++;
	inode->i_ctime = CURRENT_TIME;
	UDF_I_UCTIME(inode) = CURRENT_UTIME;
	mark_inode_dirty(inode);
	atomic_inc(&inode->i_count);
	d_instantiate(dentry, inode);
	return 0;
}

/* Anybody can rename anything with this: the permission checks are left to the
 * higher-level routines.
 */
static int udf_rename (struct inode * old_dir, struct dentry * old_dentry,
	struct inode * new_dir, struct dentry * new_dentry)
{
	struct inode * old_inode = old_dentry->d_inode;
	struct inode * new_inode = new_dentry->d_inode;
	struct udf_fileident_bh ofibh, nfibh;
	struct FileIdentDesc *ofi = NULL, *nfi = NULL, *dir_fi = NULL, ocfi, ncfi;
	struct buffer_head *dir_bh = NULL;
	int retval = -ENOENT;

	if ((ofi = udf_find_entry(old_dir, old_dentry, &ofibh, &ocfi)))
	{
		if (ofibh.sbh != ofibh.ebh)
			udf_release_data(ofibh.ebh);
		udf_release_data(ofibh.sbh);
	}
	if (!ofi || udf_get_lb_pblock(old_dir->i_sb, lelb_to_cpu(ocfi.icb.extLocation), 0) !=
		old_inode->i_ino)
	{
		goto end_rename;
	}

	nfi = udf_find_entry(new_dir, new_dentry, &nfibh, &ncfi);
	if (nfi)
	{
		if (!new_inode)
		{
			if (nfibh.sbh != nfibh.ebh)
				udf_release_data(nfibh.ebh);
			udf_release_data(nfibh.sbh);
			nfi = NULL;
		}
	}
	if (S_ISDIR(old_inode->i_mode))
	{
		Uint32 offset = udf_ext0_offset(old_inode);

		if (new_inode)
		{
			retval = -ENOTEMPTY;
			if (!empty_dir(new_inode))
				goto end_rename;
		}
		retval = -EIO;
		dir_bh = udf_bread(old_inode, 0, 0, &retval);
		if (!dir_bh)
			goto end_rename;
		dir_fi = udf_get_fileident(dir_bh->b_data, old_inode->i_sb->s_blocksize, &offset);
		if (!dir_fi)
			goto end_rename;
		if (udf_get_lb_pblock(old_inode->i_sb, cpu_to_lelb(dir_fi->icb.extLocation), 0) !=
			old_dir->i_ino)
		{
			goto end_rename;
		}
		retval = -EMLINK;
		if (!new_inode && new_dir->i_nlink >= (256<<sizeof(new_dir->i_nlink))-1)
			goto end_rename;
	}
	if (!nfi)
	{
		nfi = udf_add_entry(new_dir, new_dentry, &nfibh, &ncfi, &retval);
		if (!nfi)
			goto end_rename;
	}
	new_dir->i_version = ++event;

	/*
	 * Like most other Unix systems, set the ctime for inodes on a
	 * rename.
	 */
	old_inode->i_ctime = CURRENT_TIME;
	UDF_I_UCTIME(old_inode) = CURRENT_UTIME;
	mark_inode_dirty(old_inode);

	/*
	 * ok, that's it
	 */
	ncfi.fileVersionNum = ocfi.fileVersionNum;
	ncfi.fileCharacteristics = ocfi.fileCharacteristics;
	memcpy(&(ncfi.icb), &(ocfi.icb), sizeof(long_ad));
	udf_write_fi(new_dir, &ncfi, nfi, &nfibh, NULL, NULL);

	/* The old fid may have moved - find it again */
	ofi = udf_find_entry(old_dir, old_dentry, &ofibh, &ocfi);
	udf_delete_entry(old_dir, ofi, &ofibh, &ocfi);

	old_dir->i_version = ++event;
	if (new_inode)
	{
		new_inode->i_nlink--;
		new_inode->i_ctime = CURRENT_TIME;
		UDF_I_UCTIME(new_inode) = CURRENT_UTIME;
		mark_inode_dirty(new_inode);
	}
	old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
	UDF_I_UCTIME(old_dir) = UDF_I_UMTIME(old_dir) = CURRENT_UTIME;
	mark_inode_dirty(old_dir);

	if (dir_bh)
	{
		dir_fi->icb.extLocation = lelb_to_cpu(UDF_I_LOCATION(new_dir));
		udf_update_tag((char *)dir_fi, (sizeof(struct FileIdentDesc) +
			cpu_to_le16(dir_fi->lengthOfImpUse) + 3) & ~3);
		if (UDF_I_ALLOCTYPE(old_inode) == ICB_FLAG_AD_IN_ICB)
		{
			mark_inode_dirty(old_inode);
			old_inode->i_version = ++event;
		}
		else
			mark_buffer_dirty_inode(dir_bh, old_inode);
		old_dir->i_nlink --;
		mark_inode_dirty(old_dir);
		if (new_inode)
		{
			new_inode->i_nlink --;
			mark_inode_dirty(new_inode);
		}
		else
		{
			new_dir->i_nlink ++;
			mark_inode_dirty(new_dir);
		}
	}

	if (ofi)
	{
		if (ofibh.sbh != ofibh.ebh)
			udf_release_data(ofibh.ebh);
		udf_release_data(ofibh.sbh);
	}

	retval = 0;

end_rename:
	udf_release_data(dir_bh);
	if (nfi)
	{
		if (nfibh.sbh != nfibh.ebh)
			udf_release_data(nfibh.ebh);
		udf_release_data(nfibh.sbh);
	}
	return retval;
}

struct inode_operations udf_dir_inode_operations = {
	lookup:				udf_lookup,
	create:				udf_create,
	link:				udf_link,
	unlink:				udf_unlink,
	symlink:			udf_symlink,
	mkdir:				udf_mkdir,
	rmdir:				udf_rmdir,
	mknod:				udf_mknod,
	rename:				udf_rename,
};