On Thu, Jan 10, 2019 at 12:45 PM Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote: > > Hi all, > > I'm currently working on resurrecting the UBIFS quota patches posted back in > 2015 by Dongsheng Yang, last posted here: > > http://lists.infradead.org/pipermail/linux-mtd/2015-September/061812.html > > First of all I think work stopped there, there is no newer UBIFS quota > support I am missing, right? > > One problem with this series was that the quotactl systemcall expects a > path to a block device. UBIFS doesn't work on a block device but on a > character device instead. > The solution in this series was to pass the path to the cdev in > quotactl. A struct cdev * member was added to struct super_block which > was used to identify the superblock for a given cdev. This approach was > rejected by Christoph ("I don't think the cdev has any business in core > VFS code."). Apart from that UBIFS can not only be mounted with a path > to the character device (mount -t ubifs /dev/ubix_y /mnt) but also in > the form ubix:volname (mount -t ubifs ubix:volname /mnt) in which case > userspace doesn't have any valid path it could pass in quotactl. > > An idea out of this would be to allow to pass the mountpoint instead of > the path to the block device in quotactl which would work with nfs or > even tmpfs aswell. Would that be acceptable? Any other ideas? *kind ping* Jan, another thing Sascha and I are not sure about, what are the consistency constraints of the quota file? If I read the code correctly, quota just writes to the quota file and assumes that the file system makes sure about consistency. Either by fsck fixing the quota file or having a data journal for the quota file. In case of UBIFS where we have a data journal this should be doable. Is it okay when the quota file has S_SYNC set? -- Thanks, //richard
