Hello, >> What I do not understand here, is why the NFS server does not allow the operation, though it does if the directory is exported read-write (I tested that). > > Exported with rw,no_root_squash? And root user on NFS client could not create a file? Hmm, that is strange. I will check in a few days.
Probably I did not describe detailed enough. Root can create a file in a directory where he does not have 'official' write permissions if the NFS server exports read-write and the client does not use aufs. Root cannot create in such a directory if the NFS server exports read-only and the client uses aufs. Now, I found another strange thing with aufs: root@nfs_client:/var/lib/nfs# ls -al total 12 drwxr-xr-x 4 systemd-network nogroup 60 Mar 26 09:45 . drwxr-xr-x 32 root root 120 Mar 26 09:36 .. drwxr-xr-x 2 statd nogroup 4096 Feb 28 2009 sm drwxr-xr-x 2 statd nogroup 4096 Feb 28 2009 sm.bak -rw-r--r-- 1 root root 5 Mar 26 09:36 state root@nfs_client:/var/lib/nfs# touch file touch: cannot touch 'file': Operation not supported root@nfs_client:/var/lib/nfs# echo >> state root@nfs_client:/var/lib/nfs# touch file root@nfs_client:/var/lib/nfs# ls -al root@tombom:/var/lib/nfs# ls -al total 12 drwxr-xr-x 4 systemd-network nogroup 80 Mar 26 09:47 . drwxr-xr-x 32 root root 120 Mar 26 09:36 .. -rw-r--r-- 1 root root 0 Mar 26 09:47 file drwxr-xr-x 2 statd nogroup 4096 Feb 28 2009 sm drwxr-xr-x 2 statd nogroup 4096 Feb 28 2009 sm.bak -rw-r--r-- 1 root root 5 Mar 26 09:36 state That is, after writing something to an already existing file, the 'Operation not supported' problem suddenly disappears. Regards Christoph ------------------------------------------------------------------------------ Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/
