Re: [PATCH 3/3][RFC](Repost) ext4: add a message in remount/umount for ext4

[Theodore Tso <tytso@mit.edu>]

On Thu, Oct 01, 2009 at 12:20:17PM +0900, Toshiyuki Okajima wrote:
> I am recognizing it. But I think I have already explained its answer as follows:
>  - A print mechanism has already been included at mount time.

It's true that some file systems already are printing a message at
mount time; but when we abstract up something to the VFS layer, that's
also an opportunity to remove some kernel printk's from some
filesystems, including ext2/3/4 at the same time this feature is
introduced.

> > filesystem specific information, but that could be handled via a new
> > method function in struct super_ops:
> >
> >        mount_msg(struct super *sb, char *buf, int buflen)
> >

Note that what I was assuming is that we would is something like this
in the VFS mount code:

     printk(KERN_INFO "Device %s mounted file system type %s read-%s%s\n",
            sb->s_sid, sb->s_type->name, 
	    sb->s_flags & MS_RDONLY ? "only" : "write",
	    sb->s_op->mount_msg ? sb->s_op->mount_msg(sb) : "");

The advantage of this is that we would now have a single consistent
kernel message for all file systems, with some room for file system
specific message.

						- Ted