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Disco
Asked: 2010-12-14 12:26:37 +0800 CST

chown on a mounted NFS partition gives "Operation not permitted"

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I have a remote partition that i have mounted locally using NFS.

'mount' gives

192.168.3.1:/mnt/storage-pools/ on /pools type nfs (rw,addr=192.168.3.1)

On the server i have in exports: 

/mnt/storage-pools   *(rw,insecure,sync,no_subtree_check)

Then I try

 touch /pools/test1
 ls -lah
 -rw-r--r--  1 65534 65534    0 Dec 13 20:56 test1
 chown root.root test1
 chown: changing ownership of `test1': Operation not permitted

What am I missing ? Pulling my hairs out.

nfs permissions chown

2 Answers

  1. Best Answer

    By default the root_squash export option is turned on, therefore NFS does not allow a root user from the client to perform operations as root on the server, instead mapping it to the user/group id specified by anonuid and anongid options (default=65534). This is configurable in /etc/exports together with other export options.

    • 32

  2. Read the section of the exports(5) concerning "root squashing":

    Very often, it is not desirable that the root user on a client machine is also treated as root when accessing files on the NFS server. To this end, uid 0 is normally mapped to a different id: the so-called anony- mous or nobody uid. This mode of operation (called ‘root squashing’) is the default, and can be turned off with no_root_squash.

    So you want:

    /mnt/storage-pools   *(rw,insecure,sync,no_subtree_check,no_root_squash)

    (edited typo)

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