> Jan Kara wrote: > > Hi, > > > >> We have a proposal to implement a 2-level disk quota on ext3 and ext4. > >> > >> In two words - the aim is to have directories on ext3/4 partitions > >> which are limited by its disk usage and the number of inodes. Further > >> the plan is to allow configuring uid and gid quotas within them. > > If I understand it right, this is something like XFS's project quota, > > right? > > Not exactly. XFS tree quota actually replaces gid one. My proposal is > to add the 3rd id. Yeah, OK, but it's quite similar :) > > Also by 2-level, you mean it won't be possible to nest such subtrees? > > As I see it - nesting can be done on top of it. I mean - once we have > a tree id of an inode and if we say "id A is a sub-id of id B" we're done. But for implementation, it's kind of important whether there is going to be just one "tree" limitation for each inode, or arbitrary number of them... > > I.e. have a quota on directories a/, b/, a/b, a/c? > > > >> The main usage of this is containers. When two or more of them are > >> located on one disk their roots will be marked with a unique tree id > >> and thus the disk consumption of each container will be limited. While > >> achieving this goal having an id of what tree an inode belongs to is > >> a key requirement. > >> > >> So first we would like to ask to reserve a place on ext3 and ext4 inodes > >> for that ID. > > Do you really need to store tree ID on disk? I'd think that it should > > be enough to keep some id / pointer in memory and initialize it when we > > load inode into memory (from an id / pointer of parent directory). Then > > it would be enough to store a fact that some directory is a root of > > "quota tree" somewhere - either in extended attributes, as a flag in > > the inode, or together with quota data. > We can't do it inside ext4_nfs_get_inode unfortunately :( Right, that's nasty. OK, but as Andreas suggested, extended attributes are more flexible for this - most notably every fs supporting them would be able to support your tree quota extension. Honza -- Jan Kara <jack@xxxxxxx> SuSE CR Labs -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
