Configure CIFS Symbolic Links |
The Configure CIFS Symbolic Links page enables you to configure and control CIFS access to symbolic links.
A symbolic link is a special file created by NFS clients that points to another file or directory. A symbolic link is, in some respects, similar to a shortcut in the Windows environment.
There are two types of symbolic links:
Absolute symbolic links begin with a slash (/) and are treated as a path relative to the root of the file system.
Relative symbolic links begin with a character other than a slash (/) and are treated as a path relative to the parent directory of the symbolic link.
CIFS clients cannot create symbolic links, but they can follow the symbolic links created by NFS clients.
You can control how CIFS clients follow symbolic links in the following ways:
Preventing access of CIFS clients to symbolic links to files:
You should prevent CIFS clients from following symbolic links that point to files because Data ONTAP can update the wrong files. This problem occurs because many CIFS client applications perform operations such as writing to a temporary file, renaming the original file to a backup name, then renaming the temporary file to the original file name.
If the original file was targeted directly by a symbolic link, this sequence of operations would result in the file being stored in the directory where the symbolic link was, and the renamed symbolic link pointing at the original file rather than to the updated file.
Note: CIFS clients following symbolic links to directories (versus files) do not experience this problem.
You can prevent CIFS clients from following symbolic links that point to files in one of two ways:
Remove symbolic links to files and keep symbolic links to directories.
Disable CIFS access to symbolic links.
A cyclic directory structure is one that includes a symbolic link that uses a "dot" or "dot-dot" component to make a reference to a directory that is higher in the same tree.
A CIFS client following a cyclic directory structure looks deeper and deeper into the tree until Data ONTAP reaches its maximum path length. When this happens, Data ONTAP returns an error.
You can prevent CIFS access to cyclic directory structures in one of two ways:
Replace symbolic links that use "dot" shorthand with symbolic links that do not use the "dot" shorthand.
Disable CIFS access to cyclic directory structures.