On Thu, Apr 27, 2017 at 11:01 AM, Amir Goldstein <amir73il@xxxxxxxxx> wrote: > On Thu, Apr 27, 2017 at 10:59 AM, Christoph Hellwig <hch@xxxxxx> wrote: >> On Thu, Apr 27, 2017 at 10:58:31AM +0300, Amir Goldstein wrote: >>> Unless mounted with nouuid, copy the uuid of the filesystem to >>> struct super block s_uuid field, as several other filesystems do. >> >> This looks okay ... ish. >> >> Until we have a flag in the superblock that a given fs fills out s_uuid >> no one can rely on it. So please add the infrastructure that consumers >> can actually make use of it while you're at it. > > All right. makes sense. will do. Darrick, While I am working on the infrastructure that Christoph requested, please consider this patch as is for now, because: 1. Other filesystems do set s_uuid anyway 2. For my use case, I do check for NULL (zeros) value of s_uuid and this is pretty good validation if UUID has been filled 3. I do anticipate bikeshedding on the proposed infrastructure, mainly because of #2 above Cheers, Amir.