On Tue, Jun 23, 2009 at 10:34:49AM -0700, Linus Torvalds wrote: > That said, I do _not_ like the notion of > > > Add a new inode->i_filesystem_fop pointer > > regardless of whether it's in inode->i_op or wherever. I think we should > just handle this in the regular "inode->f_op->open" routine, the same way > we handle FMODE_EXCLUSIVE (O_EXCL), FMODE_NDELAY (O_NONBLOCK) and lack of > access rights (O_NOACCESS) in the driver open routines that currently > handle those specially (O_NDELAY is spe > > Al? i_filesystem_fop is certainly bogus, but why do we want to bother with file_operations at all? Unless you really insist on unlimited use of ioctl(2) on such beasts (and any users will be non-portable for obvious reasons anyway), there's no need to go anywhere near ->open() *or* ->f_op in general. Just add new methods to ->i_op (and we already have that coming from fs code) and teach do_filp_open() to * call permission() with new flag (MAY_TALK_TO_FS_NODE) for such open() * do not die with -ELOOP on symlinks if we have O_NOFOLLOW + your flag * do not call ->f_op->open() at all for such open() and we are all set. Hell, we can even teach sys_ioctl() that given set of ioctls maps to calls of our new methods. Taken from ->i_op... If we want full-blown ->ioctl() coming from the fs code on such opens, we will need distinct file_operations, no matter what we do with ->open(). It's also doable (we'd need ->i_fop pointing to new foofs_special_file_ops and its ->open() to be a boilerplate that would replace file->f_op with the normal one in case of normal open()), but it's more boilerplate patches and I really don't see what would it buy... Comments? -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
