Created attachment 48642 [details]
kernel config

if i mount a local nfs tree and then take the status line from /proc/mounts to remount, the kernel returns back EINVAL on me.  if i just drop the "proto=tcp", it works fine.

# tail -n1 /proc/mounts
192.168.0.2:/tftpboot/ /mnt/tmp nfs4 rw,relatime,vers=4,rsize=524288,wsize=524288,namlen=255,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=192.168.0.2,minorversion=0,local_lock=none,addr=192.168.0.2 0 0

# mount `awk '$3 == "nfs4" { print $1" "$2" -o remount,"$4 }' /proc/mounts`
# echo $?
32

# mount.nfs `awk '$3 == "nfs4" { print $1" "$2" -o remount,"$4 }' /proc/mounts`
# echo $?
32

# strace -e mount -s 4096 -v mount.nfs `awk '$3 == "nfs4" { print $1" "$2" -o remount,"$4 }' /proc/mounts`
mount("192.168.0.2:/tftpboot/", "/mnt/tmp", 0x4121bd, MS_REMOUNT|0x200000, "vers=4,rsize=524288,wsize=524288,namlen=255,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=192.168.0.2,minorversion=0,local_lock=none,addr=192.168.0.2") = -1 EINVAL (Invalid argument)