large ufs2 partitions and 'df'

[Julian Elischer]

On Sun, 11 May 2003, Kirk McKusick wrote:

> So right you are. It would be possible to get the space by nibbling
> a bit more space from MNAMELEN, but at some point we need to just bite
> the bullet and define a new structure. I am leaning towards believing
> that time is now. If we do define a new structure, I would like to
> clean up the existing one a bit. I would propose this:
> 
> #define	MFSNAMELEN	16	/* length of fs type name, including null */
> #define	MNAMELEN	80	/* size of on/from name bufs */
> struct statfs {
> 	u_int_32 f_bsize;		/* fundamental filesystem block size */
> 	u_int_32 f_iosize;		/* optimal transfer block size */
> 	int_64	 f_blocks;		/* total data blocks in filesystem */
> 	int_64	 f_bfree;		/* free blocks in fs */
> 	int_64	 f_bavail;		/* free blocks avail to non-superuser */
> 	int_64	 f_files;		/* total file nodes in filesystem */
> 	int_64	 f_ffree;		/* free file nodes in fs */
> 	u_int_64 f_syncwrites;		/* count of sync writes since mount */
> 	u_int_64 f_asyncwrites;		/* count of async writes since mount */
> 	u_int_64 f_syncreads;		/* count of sync reads since mount */
> 	u_int_64 f_asyncreads;		/* count of async reads since mount */
> 	u_int_64 f_spare[10];		/* unused spare */
> 	fsid_t	 f_fsid;		/* filesystem id */
> 	uid_t	 f_owner;		/* user that mounted the filesystem */
> 	u_int_32 f_type;		/* type of filesystem */
> 	u_int_32 f_flags;		/* copy of mount exported flags */
> 	char	 f_fstypename[MFSNAMELEN]; /* fs type name */
> 	char	 f_mntfromname[MNAMELEN];  /* mounted filesystem */
> 	char	 f_mntonname[MNAMELEN];	   /* directory on which mounted */
> };
> 
> It reorganizes things back into a rational order. It increases the
> sizes of everything that might ever want to be 64-bits to that size,
> and leaves plenty (10) of spares for future growth. Comments?

Any reason the f_type and t_flags words are not nearer the top? (if not
at the top)?

Why are f_bfree and f_blocks signed? (and f_files and f_ffree
for that matter).

(I can see why f_bavail should be signed but might it be more
useful to instead, keep a static 'reserved' value that you could 
subtract from f_bfree to get the 'user' value?)



> 
> 	Kirk McKusick
>