Re: [RFC] Slimming down struct inode

Brian F. G. Bidulock
2006-06-15T08:46:14Z

Nathan,

On Thu, 15 Jun 2006, Nathan Scott wrote:
>
> There is no IRIX/Linux compatibility layer, you're misunderstanding
> the code (which is understandable, its erm a bit crufty in places).

You gotta be kidding. It does everything in terms of an SVR 4 VFS
vnode and then converts that to Linux VFS on dentries/inodes. It was
obviously built by stuffing the Linux VFS under SVR 4 VFS code and
even documents the code as such. Things like:

| /*
| * XFS arguments structure, constructed from the arguments we
| * are passed via the mount system call.
| *
| * NOTE: The mount system call is handled differently between
| * Linux and IRIX. In IRIX we worked work with a binary data
| * structure coming in across the syscall interface from user
| * space (the mount userspace knows about each filesystem type
| * and the set of valid options for it, and converts the users
| * argument string into a binary structure _before_ making the
| * system call), and the ABI issues that this implies.
| *
| * In Linux, we are passed a comma separated set of options;
| * ie. a NULL terminated string of characters. Userspace mount
| * code does not have any knowledge of mount options expected by
| * each filesystem type and so each filesystem parses its mount
| * options in kernel space.
| *
| * For the Linux port, we kept this structure pretty much intact
| * and use it internally (because the existing code groks it).
| */
| struct xfs_mount_args {
| int flags; /* flags -> see XFSMNT_... macros below */
| int flags2; /* flags -> see XFSMNT2_... macros below */
| int logbufs; /* Number of log buffers, -1 to default */
| int logbufsize; /* Size of log buffers, -1 to default */
| char fsname[MAXNAMELEN+1]; /* data device name */
| char rtname[MAXNAMELEN+1]; /* realtime device filename */
| char logname[MAXNAMELEN+1]; /* journal device filename */
| char mtpt[MAXNAMELEN+1]; /* filesystem mount point */
| int sunit; /* stripe unit (BBs) */
| int swidth; /* stripe width (BBs), multiple of sunit */
| uchar_t iosizelog; /* log2 of the preferred I/O size */
| int ihashsize; /* inode hash table size (buckets) */
| };

No... No compatibility layer there.