Messages in this thread | | | Date | Mon, 25 Aug 2003 21:03:32 +0100 | From | viro@parcelfa ... | Subject | Re: [PATCH] Add MOUNT_STATUS ioctl to cdrom device |
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On Tue, Aug 26, 2003 at 01:22:37AM +0700, Samphan Raruenrom wrote: > Hi, > > This patch add a new ioctl MOUNT_STATUS to the 2.4 kernel's cdrom > device. It'll be used as an API to query the mount status of a > cdrom :- > > CDROM_MOUNT_STATUS > Return :- > 0 = not mount. > 1 = mounted, but not in-use. It is ok to umount. > 2 = busy. Umount will result in getting EBUSY. > <0 = error.
Huh? And what, pray tell, makes cdrom special? Not to mention the use of ioctl, the inherent raciness of the interface and the fact that yes,
> This same functionality can be done in user-space,
... which should be the end of it.
> + case CDROM_MOUNT_STATUS: { > + struct super_block *sb = get_super(dev); > + if (sb == NULL) return -EINVAL; > + down_read(¤t->namespace->sem); > + struct vfsmount *mnt = NULL; > + struct list_head *p; > + list_for_each(p, ¤t->namespace->list) { > + struct vfsmount *m = list_entry(p, struct vfsmount, > mnt_list); > + if (sb == m->mnt_sb) { > + mnt = m; break; > + } > + } > + up_read(¤t->namespace->sem);
And what about other namespaces?
> + drop_super(sb); > + int mstat = 0; /* 0 not mounted, 1 umount ok, 2 umount EBUSY > */ > + if (mnt) mstat = 1 + (atomic_read(&mnt->mnt_count) > 1);
Or the possibility that * mnt might've been freed by that point. * we might have the damn thing mounted in several places, some busy, some not. * cdrom had been used not by mount. * cdrom had been mounted just as we had decided to tell that it's not busy. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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