Hi, > > I think the problem is that the submount doesn't appear in /proc/mounts. > > "nfsd_fh()" in nfs-utils needs to be able to map from the uuid for a filesystem to > > the mount point. To do this it walks through /proc/mounts checking the uuid of > > each filesystem. If a filesystem isn't listed there, it obviously fails. > > > > I guess you could add code to nfs-utils to do whatever "btrfs subvol list" does to > > make up for the fact that btrfs doesn't register in /proc/mounts. > > > > NeilBrown > > I've been watching this with interest for the nfs-ganesha project. We recently were made aware that we weren't working with btrfs subvols, and I added code so that in addition to using getmntent (essentially /proc/mounts) to populate filesystems, we also scan for btrfs subvols and with that we are able to export subvols. My question is does a snapshot look any different than a subvol? If they show up in the subvol list then we shouldn't need to do anything more for nfs-ganesha, but if there's something else needed to discover them, then we may need additional code in nfs-ganesha. I have not yet had a chance to check out exporting a snapshot yet. > My question is does a snapshot look any different than a subvol? No difference between btrfs subvol and snapshot in theory. but the btrfs subvol number in product env is usually fixed, and the btrfs snapshot number is usually dynamic. For fixed-number btrfs subvol/snapshot, it is OK to put them in the same hierarchy, and then export all in /etc/exports static, as a walk around. For dynamic-number btrfs snapshot number, we needs a dynamic way to export them in nfs. Best Regards Wang Yugui (wangyugui@xxxxxxxxxxxx) 2021/06/21
