namei.c

这是Linux系统下的对UDF文件系统新增的功能

	{
		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 (compstart[0] == '.')
		{
			if ((symname-compstart) == 1)
				pc->componentType = 4;
			else if ((symname-compstart) == 2 && compstart[1] == '.')
				pc->componentType = 3;
		}

		if (pc->componentType == 5)
		{
			if ( !(namelen = udf_put_filename(inode->i_sb, compstart, name, symname-compstart)))
				goto out_no_entry;

			if (elen + sizeof(struct pathComponent) + namelen > eoffset)
				goto out_no_entry;
			else
				pc->lengthComponentIdent = namelen;

			memcpy(pc->componentIdent, name, namelen);
		}

		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) == ICBTAG_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_t uniqueID;
		lvhd = (struct logicalVolHeaderDesc *)(UDF_SB_LVID(inode->i_sb)->logicalVolContentsUse);
		uniqueID = le64_to_cpu(lvhd->uniqueID);
		*(uint32_t *)((struct allocDescImpUse *)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), 1);
	}
	udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
	if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB)
	{
		mark_inode_dirty(dir);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,14)
		dir->i_version = ++event;
#else
		dir->i_version = ++global_event;
#endif
	}
	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;
}

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 LINUX_VERSION_CODE < KERNEL_VERSION(2,2,6)
	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
		return -EPERM;
#endif

	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_t uniqueID;
		lvhd = (struct logicalVolHeaderDesc *)(UDF_SB_LVID(inode->i_sb)->logicalVolContentsUse);
		uniqueID = le64_to_cpu(lvhd->uniqueID);
		*(uint32_t *)((struct allocDescImpUse *)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), 1);
	}
	udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
	if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB)
	{
		mark_inode_dirty(dir);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,14)
		dir->i_version = ++event;
#else
		dir->i_version = ++global_event;
#endif
	}
	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);
	inode->i_count ++;
	d_instantiate(dentry, inode);
	return 0;
}


#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,6)

/*
 * rename uses retrying to avoid race-conditions: at least they should be
 * minimal.
 * it tries to allocate all the blocks, then sanity-checks, and if the sanity-
 * checks fail, it tries to restart itself again. Very practical - no changes
 * are done until we know everything works ok.. and then all the changes can be
 * done in one fell swoop when we have claimed all the buffers needed.
 *
 * Anybody can rename anything with this: the permission checks are left to the
 * higher-level routines.
 */
static int do_udf_rename(struct inode *old_dir, struct dentry *old_dentry,
	struct inode *new_dir, struct dentry *new_dentry)
{
	struct inode * old_inode, * new_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 (old_dentry->d_name.len > UDF_NAME_LEN)
		goto end_rename;

	old_inode = old_dentry->d_inode;
	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;
	}

	new_inode = new_dentry->d_inode;
	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;
		}
		else
		{
			DQUOT_INIT(new_inode);
		}
	}
	retval = 0;
	if (new_inode == old_inode)
		goto end_rename;
	if (S_ISDIR(old_inode->i_mode))
	{
		uint32_t offset = udf_ext0_offset(old_inode);
		retval = -EINVAL;
		if (is_subdir(new_dentry, old_dentry))
			goto end_rename;

		if (new_inode)
		{
			/* Prune any children before testing for busy */
			if (new_dentry->d_count > 1)
				shrink_dcache_parent(new_dentry);
				retval = -EBUSY;
				if (new_dentry->d_count > 1)
					goto end_rename;
			retval = -ENOTEMPTY;
			if (!empty_dir(new_inode))
				goto end_rename;
		}
		if (UDF_I_ALLOCTYPE(old_inode) == ICBTAG_FLAG_AD_IN_ICB)
		{
			dir_fi = udf_get_fileident(UDF_I_DATA(old_inode) -
				(UDF_I_EFE(old_inode) ?
					sizeof(struct extendedFileEntry) :
					sizeof(struct fileEntry)),
				old_inode->i_sb->s_blocksize, &offset);
		}
		else
		{
			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_inode, 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_fi)
	{
		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) == ICBTAG_FLAG_AD_IN_ICB)
		{
			mark_inode_dirty(old_inode);
			old_inode->i_version = ++event;
		}
		else
			mark_buffer_dirty(dir_bh, 1);
		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);
		}
	}

	/* Update the dcache */
	d_move(old_dentry, new_dentry);

	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;
}

/* Ok, rename also locks out other renames, as they can change the parent of
 * a directory, and we don't want any races. Other races are checked for by
 * "do_rename()", which restarts if there are inconsistencies.
 *
 * Note that there is no race between different filesystems: it's only within
 * the same device that races occur: many renames can happen at once, as long
 * as they are on different partitions.
 *
 * In the udf file system, we use a lock flag stored in the memory
 * super-block.  This way, we really lock other renames only if they occur
 * on the same file system
 */

int udf_rename(struct inode *old_dir, struct dentry *old_dentry,
	struct inode *new_dir, struct dentry *new_dentry)
{
	int result;

	while (UDF_SB_RENAME_LOCK(old_dir->i_sb))
		sleep_on(&UDF_SB_RENAME_WAIT(old_dir->i_sb));
	UDF_SB_RENAME_LOCK(old_dir->i_sb) = 1;
	result = do_udf_rename(old_dir, old_dentry, new_dir, new_dentry);
	UDF_SB_RENAME_LOCK(old_dir->i_sb) = 0;
	wake_up(&UDF_SB_RENAME_WAIT(old_dir->i_sb));
	return result;
}

#else

/* Anybody can rename anything with this: the permission checks are left to the
 * higher-level routines.
 */
int udf_rename (struct inode * old_dir, struct dentry * old_dentry,
	struct inode * new_dir, struct dentry * new_dentry)
{
	struct inode * old_inode, * new_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;

	old_inode = old_dentry->d_inode;
	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;
	}

	new_inode = new_dentry->d_inode;
	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;
		}
		else
		{
			DQUOT_INIT(new_inode);
		}
	}
	if (S_ISDIR(old_inode->i_mode))
	{
		uint32_t 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;
	}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,14)
	new_dir->i_version = ++event;
#else
	new_dir->i_version = ++global_event;
#endif

	/*
	 * 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_inode, ofi, &ofibh, &ocfi);

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,14)
	old_dir->i_version = ++event;
#else
	old_dir->i_version = ++global_event;
#endif
	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) == ICBTAG_FLAG_AD_IN_ICB)
		{
			mark_inode_dirty(old_inode);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,14)
			old_inode->i_version = ++event;
#else
			old_inode->i_version = ++global_event;
#endif
		}
		else
			mark_buffer_dirty(dir_bh, 1);
		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;
}
#endif