1bf490ba93
When using "zfs destroy" on a dataset that is using "sharenfs=on" and has been automatically exported (by libzfs), the dataset will not be automatically unexported as it should be. This workflow appears to have been broken by this commit: 3fd3e56cfd543d7d7a1bf502bfc0db6e24139668 In that change, the "zfs_unmount" function was modified to use the "mnt.mnt_special" field when determining the mount point that is being unmounted, rather than "mnt.mnt_mountp". As a result, when "mntpt" is passed into "zfs_unshare_proto", it's value is now the dataset name rather than the mountpoint. Thus, when this value is used with the "is_shared" function (via "zfs_unshare_proto") it will not find a match (since that function assumes it'll be passed the mountpoint) and incorrectly reports that the dataset is not shared. This can be easily reproduced with the following commands: $ sudo zpool create tank xvdb $ sudo zfs create -o sharenfs=on tank/fish $ sudo zfs destroy tank/fish $ sudo zfs list -r tank NAME USED AVAIL REFER MOUNTPOINT tank 97.5K 7.27G 24K /tank $ sudo exportfs /tank/fish <world> $ sudo cat /etc/dfs/sharetab /tank/fish - nfs rw,crossmnt At this point, the "tank/fish" filesystem doesn't exist, but it's still listed as exported when looking at "exportfs" and "/etc/dfs/sharetab". Also note, this change brings us back in-sync with the illumos code, as it pertains to this one line; on illumos, "mnt.mnt_mountp" is used. Reviewed by: loli10K <ezomori.nozomu@gmail.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Co-authored-by: George Wilson <george.wilson@delphix.com> Signed-off-by: Prakash Surya <prakash.surya@delphix.com> Issue #6143 Closes #7941