[PATCH 09/18] xstat: Make special system filesystems return FS_SPECIAL_FL [ver #6]

[David Howells]

Christoph Hellwig <hch at infradead.org> wrote:

> special is not a very useful identifier.  Also what you are returning
> is per-filesystem data, not per-file.  This needs to go into statfs,
> not into stat.  We're about to introduce flags for statfs, so try
> to do it ontop of those.
> 
> The same thing applies to the remote flag in the next patch.

Which means that you have to do two calls (xstat+statfs) to find this
information that we can return pretty much for free here, though you can cache
it based on st_dev, I suppose.

Also, not all the flags are per-filesystem.  The following are:

	FS_SPECIAL_FL		/* Special file as found in procfs/sysfs */
	FS_REMOTE_FL		/* File is remote */

but the rest aren't:

	FS_AUTOMOUNT_FL		/* Specific automount point */
	FS_AUTOMOUNT_ANY_FL	/* Unspecific automount directory */
	FS_ENCRYPTED_FL		/* File is encrypted */
	FS_HIDDEN_FL		/* File is marked hidden (DOS+) */
	FS_SYSTEM_FL		/* File is marked system (DOS+) */
	FS_ARCHIVE_FL		/* File is marked archive (DOS+) */
	FS_TEMPORARY_FL		/* File is temporary (NTFS/CIFS) */
	FS_OFFLINE_FL		/* File is offline (CIFS) */
	FS_REPARSE_POINT_FL	/* Reparse point (NTFS/CIFS) */

David