Re: [PATCH v6 12/16] ntfs: add reparse and ea operations

[Christoph Hellwig <hch@lst.de>]

Suggested commit message:

Implement support for Extended Attributes and Reparse Points, enabling
Posix ACL support and, and compatibility with Windows Subsystem for
Linux (WSL) metadata.

> +struct WSL_LINK_REPARSE_DATA {
> +	__le32	type;
> +	char	link[];
> +};
> +
> +struct REPARSE_INDEX {			/* index entry in $Extend/$Reparse */

Why are these using all upper case names unlike the rest of the
code?

> +	ok = ni && reparse_attr && (size >= sizeof(struct reparse_point)) &&
> +		(reparse_attr->reparse_tag != IO_REPARSE_TAG_RESERVED_ZERO) &&
> +		(((size_t)le16_to_cpu(reparse_attr->reparse_data_length) +
> +		  sizeof(struct reparse_point) +
> +		  ((reparse_attr->reparse_tag & IO_REPARSE_TAG_IS_MICROSOFT) ?
> +		   0 : sizeof(struct guid))) == size);

A bunch of superflous braces.  But in general decomposing such complex
operations into an inline helper using multiple if statements and
adding comments improves the readability a lot.

> +	if (ok) {

... and just return here for !ok and reduce the indentation for
the rest of the function?

> +		switch (reparse_attr->reparse_tag) {
> +		case IO_REPARSE_TAG_LX_SYMLINK:
> +			wsl_reparse_data = (const struct WSL_LINK_REPARSE_DATA *)
> +						reparse_attr->reparse_data;
> +			if ((le16_to_cpu(reparse_attr->reparse_data_length) <=
> +			     sizeof(wsl_reparse_data->type)) ||
> +			    (wsl_reparse_data->type != cpu_to_le32(2)))
> +				ok = false;
> +			break;
> +		case IO_REPARSE_TAG_AF_UNIX:
> +		case IO_REPARSE_TAG_LX_FIFO:
> +		case IO_REPARSE_TAG_LX_CHR:
> +		case IO_REPARSE_TAG_LX_BLK:
> +			if (reparse_attr->reparse_data_length ||
> +			    !(ni->flags & FILE_ATTRIBUTE_RECALL_ON_OPEN))
> +				ok = false;
> +			break;

... and then directly return from inside the switch as well?