我遇到了一个问题，我已经在 Google 上搜索了至少6 小时28 小时，但毫无收获。每当我尝试挂载目录时，都会收到以下错误（末尾有详细版本）：
mount.nfs：挂载时服务器拒绝访问：
最初我将其用作computer1nfs 服务器，但我已将其移至computer2并尝试将其挂载computers3-8。另外需要注意的是，computer2现在充当所有其他计算机（甚至computer1）的 dhcp 路由器，但我几乎可以肯定问题与 的 nfs 设置有关，computer2因为我已尝试以下操作：
- 尝试将原始
computer1服务器中的文件夹挂载到其中一个computers3-8客户端 -成功 - 尝试将原始
computer1服务器中的文件夹挂载到新computer2服务器——成功 - 尝试将新服务器上的文件夹挂载
computer2到其中一个computers3-8客户端——失败 - 尝试将文件夹从新
computer2服务器挂载到旧computer1服务器--失败 - 尝试导出然后安装任何其他文件夹
computer2——失败 - ssh 往返
computer2--成功
除此之外，我还检查了文件的相关部分，确保/etc/exports没有任何错误。因此，我几乎绝对确定这不是权限问题。
问题： 鉴于这不是网络错误，有人可以建议我如何开始调试这个问题吗？
详细输出：
mount: proc already mounted on /proc
mount: /dev/mmcblk0p5 already mounted on /boot
mount: tmpfs already mounted on /var/tmp
mount: tmpfs already mounted on /var/log
mount.nfs: timeout set for Fri Nov 15 07:27:02 2013
mount.nfs: trying text-based options 'vers=3,rsize=8192,wsize=8192,nolock,addr=192.168.7.1'
mount.nfs: prog 100003, trying vers=3, prot=6
mount.nfs: trying 192.168.7.1 prog 100003 vers 3 prot TCP port 2049
mount.nfs: prog 100005, trying vers=3, prot=17
mount.nfs: trying 192.168.7.1 prog 100005 vers 3 prot UDP port 37300
mount.nfs: mount(2): Permission denied
mount.nfs: access denied by server while mounting 192.168.7.1:/home/raspi/Documents/raspi/raspi
详细输出2：
这是一种更直接的方法，它将挂载隔离到这里仅涉及的目录：
$ sudo mount -v -o "vers=3" 192.168.7.1:/home/raspi/Documents/raspi/raspi /home/raspi/test
mount: no type was given - I'll assume nfs because of the colon
mount.nfs: timeout set for Fri Nov 15 07:47:38 2013
mount.nfs: rpc.statd is not running but is required for remote locking.
mount.nfs: Either use '-o nolock' to keep locks local, or start statd.
mount.nfs: an incorrect mount option was specified
我以前遇到过这个rpc.statd is not running but is required for remote locking错误，但是世界上所有的谷歌搜索都对我没有任何帮助......
编辑：
混乱要求我执行以下命令并显示结果：
首先在服务器上：
SERVER$ sudo exportfs -rv
exporting raspi1:/home/raspi/Documents/raspi/raspi
exporting raspi2:/home/raspi/Documents/raspi/raspi
exporting raspi3:/home/raspi/Documents/raspi/raspi
exporting raspi4:/home/raspi/Documents/raspi/raspi
exporting raspi5:/home/raspi/Documents/raspi/raspi
exporting raspi6:/home/raspi/Documents/raspi/raspi
exporting raspi7:/home/raspi/Documents/raspi/raspi
exporting raspi8:/home/raspi/Documents/raspi/raspi
exporting raspi9:/home/raspi/Documents/raspi/raspi
exporting raspi10:/home/raspi/Documents/raspi/raspi
exporting raspi11:/home/raspi/Documents/raspi/raspi
exporting raspi12:/home/raspi/Documents/raspi/raspi
exporting raspi13:/home/raspi/Documents/raspi/raspi
exporting raspi14:/home/raspi/Documents/raspi/raspi
exporting raspi15:/home/raspi/Documents/raspi/raspi
exporting raspi16:/home/raspi/Documents/raspi/raspi
exporting raspi17:/home/raspi/Documents/raspi/raspi
exporting raspi18:/home/raspi/Documents/raspi/raspi
exporting raspi19:/home/raspi/Documents/raspi/raspi
exporting raspi20:/home/raspi/Documents/raspi/raspi
exporting raspi21:/home/raspi/Documents/raspi/raspi
exporting raspi22:/home/raspi/Documents/raspi/raspi
exporting raspi23:/home/raspi/Documents/raspi/raspi
exporting raspi24:/home/raspi/Documents/raspi/raspi
exporting raspi25:/home/raspi/Documents/raspi/raspi
exporting raspi26:/home/raspi/Documents/raspi/raspi
exporting raspi27:/home/raspi/Documents/raspi/raspi
exporting raspi28:/home/raspi/Documents/raspi/raspi
exporting raspi29:/home/raspi/Documents/raspi/raspi
exporting raspi30:/home/raspi/Documents/raspi/raspi
exporting raspi5:/home/raspi/Downloads
exporting 192.168.7.105:/home/raspi/Documents/raspi
然后在客户端
CLIENT$ showmount -e 192.168.7.1
Export list for 192.168.7.1:
/home/raspi/Documents/raspi 192.168.7.105
/home/raspi/Documents/raspi/raspi raspi30,raspi29,raspi28,raspi27,raspi26,raspi25,raspi24,raspi23,raspi22,raspi21,raspi20,raspi19,raspi18,raspi17,raspi16,raspi15,raspi14,raspi13,raspi12,raspi11,raspi10,raspi9,raspi8,raspi7,raspi6,raspi5,raspi4,raspi3,raspi2,raspi1
/home/raspi/Downloads raspi5
CLIENT$ sudo mount -a
mount.nfs: access denied by server while mounting 192.168.7.1:/home/raspi/Documents/raspi/raspi
CLIENT$ sudo tail -f /var/log/daemon.log 2>&1
Nov 15 21:35:55 raspi5 dhclient: bound to 192.168.7.105 -- renewal in 250 seconds.
Nov 15 21:40:05 raspi5 dhclient: DHCPREQUEST on eth0 to 192.168.7.1 port 67
Nov 15 21:40:05 raspi5 dhclient: DHCPACK from 192.168.7.1
Nov 15 21:40:05 raspi5 dhclient: bound to 192.168.7.105 -- renewal in 294 seconds.
Nov 15 21:44:59 raspi5 dhclient: DHCPREQUEST on eth0 to 192.168.7.1 port 67
Nov 15 21:44:59 raspi5 dhclient: DHCPACK from 192.168.7.1
Nov 15 21:44:59 raspi5 dhclient: bound to 192.168.7.105 -- renewal in 262 seconds.
Nov 15 21:49:21 raspi5 dhclient: DHCPREQUEST on eth0 to 192.168.7.1 port 67
Nov 15 21:49:21 raspi5 dhclient: DHCPACK from 192.168.7.1
Nov 15 21:49:21 raspi5 dhclient: bound to 192.168.7.105 -- renewal in 273 seconds.
编辑2：
混乱要求我进一步执行以下命令并显示结果：
SERVER$ ping raspi5
PING raspi5 (192.168.7.105) 56(84) bytes of data.
64 bytes from raspi5 (192.168.7.105): icmp_seq=1 ttl=64 time=0.699 ms
64 bytes from raspi5 (192.168.7.105): icmp_seq=2 ttl=64 time=0.683 ms
SERVER$ sudo tail -f /var/log/daemon.log
tail: cannot open ‘/var/log/daemon.log’ for reading: No such file or directory
这是我/etc/exports在服务器上的文件。如您所见，我尝试使用 中定义的名称/etc/hosts、其 IP 地址，并且还尝试导出到不同的文件夹。我省略了所有其他行，因为它们只是最后一行的重复，只是重定向到不同的 raspi。
# /etc/exports: the access control list for filesystems which may be exported
# to NFS clients. See exports(5).
#
# Example for NFSv2 and NFSv3:
# /srv/homes hostname1(rw,sync,no_subtree_check) hostname2(ro,sync,no_subtree_check)
#
# Example for NFSv4:
# /srv/nfs4 gss/krb5i(rw,sync,fsid=0,crossmnt,no_subtree_check)
# /srv/nfs4/homes gss/krb5i(rw,sync,no_subtree_check)
#
/home/raspi/Downloads raspi5(rw,sync,no_subtree_check,no_root_squash)
/home/raspi/Documents/raspi/ 192.168.7.105(rw,sync,no_subtree_check,no_root_squash,fsid=0)
/home/raspi/Documents/raspi/raspi raspi5(rw,sync,no_subtree_check,no_root_squash,fsid=0)
这是我/etc/fstab在 raspi5 客户端上的文件
proc /proc proc defaults 0 0
/dev/mmcblk0p5 /boot vfat defaults 0 2
/dev/mmcblk0p6 / ext4 defaults,noatime 0 1
# a swapfile is not a swap partition, so no using swapon|off from here on, use dphys-swapfile swap[on|off] for that
#automatically mount the shared raspi folder(s)
# Remember that NFS4 is AIDS, so use NFS3
192.168.7.1:/home/raspi/Documents/raspi/raspi /home/raspi/ nfs nfsvers=3,rsize=8192,wsize=8192,rw,auto,nolock 0 0
# Move highly used directories to RAM
tmpfs /var/tmp tmpfs nodev,nosuid,size=50M 0 0
tmpfs /var/log tmpfs nodev,nosuid,size=50M 0 0
编辑3：
遵循一些建议这里我也在insecure导出中设置了标志，但是无济于事，这里是rpcinfo -p客户端和服务器上的输出：
CLIENT$ sudo rpcinfo -p
program vers proto port service
100000 4 tcp 111 portmapper
100000 3 tcp 111 portmapper
100000 2 tcp 111 portmapper
100000 4 udp 111 portmapper
100000 3 udp 111 portmapper
100000 2 udp 111 portmapper
100024 1 udp 53553 status
100024 1 tcp 60026 status
SERVER$ rpcinfo -p
program vers proto port service
100000 4 tcp 111 portmapper
100000 3 tcp 111 portmapper
100000 2 tcp 111 portmapper
100000 4 udp 111 portmapper
100000 3 udp 111 portmapper
100000 2 udp 111 portmapper
100024 1 udp 42430 status
100024 1 tcp 49377 status
100003 2 tcp 2049 nfs
100003 3 tcp 2049 nfs
100003 4 tcp 2049 nfs
100227 2 tcp 2049
100227 3 tcp 2049
100003 2 udp 2049 nfs
100003 3 udp 2049 nfs
100003 4 udp 2049 nfs
100227 2 udp 2049
100227 3 udp 2049
100021 1 udp 33106 nlockmgr
100021 3 udp 33106 nlockmgr
100021 4 udp 33106 nlockmgr
100021 1 tcp 47922 nlockmgr
100021 3 tcp 47922 nlockmgr
100021 4 tcp 47922 nlockmgr
100005 1 udp 50875 mountd
100005 1 tcp 53329 mountd
100005 2 udp 53583 mountd
100005 2 tcp 42062 mountd
100005 3 udp 36556 mountd
100005 3 tcp 39984 mountd
编辑4：
进一步遵循一些建议这里我得到了以下调试日志：
[ 2233.803852] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
[ 2233.803885] NFSD: starting 90-second grace period (net ffffffff81cd29c0)
[ 3261.750455] nfsd: last server has exited, flushing export cache
[ 3262.912654] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
[ 3262.912688] NFSD: starting 90-second grace period (net ffffffff81cd29c0)
[ 5231.798334] nfsd: last server has exited, flushing export cache
[ 5232.956633] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
[ 5232.956668] NFSD: starting 90-second grace period (net ffffffff81cd29c0)
[ 5350.889640] nfsd: last server has exited, flushing export cache
[ 5352.023534] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
[ 5352.023577] NFSD: starting 90-second grace period (net ffffffff81cd29c0)
[ 5517.837425] nfsd: last server has exited, flushing export cache
[ 5518.987793] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
[ 5518.987826] NFSD: starting 90-second grace period (net ffffffff81cd29c0)
[56604.080162] Netfilter messages via NETLINK v0.30.
[56707.453535] nfsd: last server has exited, flushing export cache
[56708.605020] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
[56708.605057] NFSD: starting 90-second grace period (net ffffffff81cd29c0)
[57338.926093] NFSD: laundromat service - starting
[57338.926105] NFSD: laundromat_main - sleeping for 90 seconds
[57363.216188] nfsd: freeing readahead buffers.
[57363.216244] nfsd: last server has exited, flushing export cache
[57364.351041] set_max_drc nfsd_drc_max_mem 6008832
[57364.354764] nfsd: creating service
[57364.354771] nfsd: allocating 32 readahead buffers.
[57364.356023] nfsd4_umh_cltrack_upcall: cltrack_prog is disabled
[57364.356040] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
[57364.356072] NFSD: starting 90-second grace period (net ffffffff81cd29c0)
[57364.369688] nfsd_dispatch: vers 3 proc 0
[57372.738225] nfsd_dispatch: vers 4 proc 0
[57372.753507] nfsd_dispatch: vers 4 proc 1
[57372.753521] nfsv4 compound op #1/3: 24 (OP_PUTROOTFH)
[57372.755550] exp_export: export of invalid fs type.
[57372.755679] found domain 192.168.7.105,raspi5
[57372.755685] found fsidtype 1
[57372.755690] found fsid length 4
[57372.755695] Path seems to be <>
[57372.755722] nfsv4 compound op ffff8801a47ec080 opcnt 3 #1: 24: status 2
[57372.755731] nfsv4 compound returned 2
[57372.779429] nfsd_dispatch: vers 3 proc 0
[57372.792595] exp_export: export of invalid fs type.
编辑5：
我取得了一些进展，并得出了以下结论
- 这不是端口问题，因为客户端可以 telnet 到主机
telnet 192.168.7.1 2049 - 它是大概这不是网络问题，因为服务器甚至无法自行安装
- 支持（现在仍然支持）挂载的旧版本正在运行
nfs-kernel-server 1:1.2.4-1，而不支持挂载的新服务器正在运行nfs-kernel-server 1:1.2.8-2 - 该命令
sudo /etc/init.d/portmap restart在旧服务器上有效，但在新服务器上无效，这告诉我新服务器上缺少端口映射。但是，当我尝试通过安装它时sudo apt-get install portmap，它告诉我Note, selecting 'rpcbind' instead of 'portmap', and thatrpcbind 已经是最新版本`
编辑6：
iptables -L这是我的服务器上的输出：
Chain INPUT (policy ACCEPT)
target prot opt source destination
Chain FORWARD (policy DROP)
target prot opt source destination
ACCEPT all -- anywhere anywhere ctstate RELATED,ESTABLISHED
ACCEPT all -- anywhere anywhere
LOG all -- anywhere anywhere LOG level warning
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
并且正确的端口已打开：
CLIENT$ nmap -P0 192.168.7.1
Starting Nmap 6.00 ( http://nmap.org ) at 2013-11-16 06:44 UTC
Nmap scan report for raspiserver (192.168.7.1)
Host is up (0.0095s latency).
Not shown: 996 closed ports
PORT STATE SERVICE
22/tcp open ssh
80/tcp open http
111/tcp open rpcbind
2049/tcp open nfs
Nmap done: 1 IP address (1 host up) scanned in 1.55 seconds
答案1
我遇到了与楼主相同的问题。以前这个方法对我有用，但更新后就不行了。解决办法是添加“nfsvers=3”选项。
答案2
值得一提的是（即使这里可能不是这种情况），如果您在重命名文件夹或尝试访问新文件夹后突然收到此错误，您可能忘记了您实际上必须指定服务器端哪些文件夹是共享的，哪些不是/etc/exports——这是我的情况的问题。
修改该文件后，你还需要执行sudo service nfs-kernel-server restart
答案3
我的两个同事刚刚在 Vagrant 中解决了类似的问题。AppArmor 是罪魁祸首，可以找到解决方案这里，引用：
mount: cannot mount block device /some/path read-only
dmesg 显示：
[ 6944.194280] type=1400 audit(1385049795.420:32): apparmor="DENIED" operation="mount" info="failed type match" error=-13 parent=6631 profile="lxc-container-default" name="/some/other/path" pid=6632 comm="mount" srcname="/some/path" flags="rw, bind"
AppArmor 正在阻止 LXC 容器内的 mount -o bind。
要启用 id 添加/etc/apparmor.d/lxc/lxc-default：
profile lxc-container-default flags=(attach_disconnected,mediate_deleted) {
...
mount options=(rw, bind),
...
重新加载装甲：
# /etc/init.d/apparmor reload
答案4
如果服务器未安装在本地主机上，则问题不在于网络。
查看 /etc/hosts.deny 和 /etc/hosts.allow。
只为进一步的问题...：我玩了几天的 NFS 旧版本。我在两台主机之间有一个中间交换机，允许从 ServerIP<->ClientIP 进行所有 TCP 和 UDP 通信，telnet 在每个端口上都可以工作...但 rpcinfo -p 不行。
我们发现交换机有一项名为“检查”的功能，可以检查所有“sunrpc”数据包，如果版本不在“允许”的版本中，则丢弃数据包而不记录任何内容。它被称为“应用层协议检查”。http://www.cisco.com/c/en/us/td/docs/security/fwsm/fwsm31/configuration/guide/fwsm_cfg/inspct_f.html#wp1349924
在此之后我们还发现我们必须为防火墙配置静态端口，但这是另一个问题。