On 24 Oct 2023, at 13:12, Amir Goldstein wrote: > On Tue, Oct 24, 2023 at 6:32 PM Benjamin Coddington <bcodding@xxxxxxxxxx> wrote: >> Yes, but if the specific export is on the same server's filesystem as the >> "root", you'll still get zero. There are various ways to set fsid on >> exports for linux servers, but the fsid will be the same for all exports of >> the same filesystem on the server. >> > > OK. good to know. I thought zero fsid was only for the root itself. Yes, but by "root" here I always mean the special NFSv4 root - the special per-server global root filehandle. ... >> I'm not familiar with fanotify enough to know if having multiple fsid 0 >> mounts of different filesystems on different servers will do the right >> thing. I wanted to point out that very real possibility for v4. >> > > The fact that fsid 0 would be very common for many nfs mounts > makes this patch much less attractive. > > Because we only get events for local client changes, we do not > have to tie the fsid with the server's fsid, we could just use a local > volatile fsid, as we do in other non-blockdev fs (tmpfs, kernfs). A good way to do this would be to use the nfs_server->s_dev's major:minor - this represents the results of nfs_compare_super(), so it should be the same value if NFS is treating it as the same filesystem. > I am not decisive about the best way to tackle this and since > Jan was not sure about the value of local-only notifications > for network filesystems, I am going to put this one on hold. > > Thanks for the useful feedback! Sure! Ben
