Exporting Considerations
Mounted File System Loops
Users and administrators can encounter difficulty with the inability of NFS to export
an already-mounted Network File System. NFS will not allow the export of a
mounted file system because of the possibility of mounted file system loops. This
problem would occur if NFS allowed the mount and then new clients mounted the
namespace. The new clients would then discover that to
find
the mount point, they
would have to
pass through
the mount point. They would never get to the bottom of
the directory, which would keep recycling the path to infinity.The mount daemon
would run into a never-ending string, thus causing client failure.
Mounted File System Loops Solution
This problem will not occur because NFS will not allow the export of an
already-mounted NFS file system.
Symbolic Links
The Network File System supports the use of symbolic links. Symbolic links are
the representations of path names that are in the form of a path contained in a file.
The actual path is determined by doing a path search based on the contents of the
file.
Two path names can lead to the same object because one is a symbolic link. For
example, the directory /nancy can contain a symbolic link to /home/grad/kathryn so
that the path to an object in /home/grad/kathryn can also be /nancy. The two path
names are the same. If a user exports both entries, then both will export normally.
Exporting /home/grad/kathryn is the
same
as exporting /nancy. NFS exports
objects
, and not
path names
, so the last occurrence of the object export will be the
only one that requires saving in the export table.
For more information about symbolic links, see
Integrated File System Introduction,
SC41-4711.
38 OS/400 Network File System Support V4R4
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