On Sat 03-10-15 23:31:19, Christoph Hellwig wrote: > On Tue, Sep 15, 2015 at 05:01:56PM +0800, Dongsheng Yang wrote: > > There are some filesystems are running on char devs, such > > as ubifs. So we need a field in super_block to hold a > > reference to the char device. > > We only care about the block device to get a device number to return > in st.st_dev. And while filesystem literally run on top of a block > device that is not the case of a character device - you might use a > chardev to identify a device to mount but it'll never use the actual > char device. > > So please don't bloat the superblock with this. Hum, interesting idea. You're right that using anon bdev ubifs got assigned in set_anon_super() would work as well. It may be slightly confusing for quota-tools usage where specifying char device on command line would not work (specifying block device to identify filesystem works there). But using mount point would work fine so the situation would be the same as with network filesystems. We could even add a translation in quota-tools to convert char device to corresponding anon block device if there's a reasonably simple way to do that in userspace or we could translate in quotactl code in kernel if that's any easier. But currently I don't see a way how we could easily do either of those. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR -- 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
