5-4 Dell PowerVault 720N, 740N, and 760N System Administrator and Command Reference Guide

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You can create directory structures that are cyclic by creating a symbolic link that
refers to a directory higher in the same tree, through use of a symbolic link having a
dot or dot-dot component. Therefore, a simple recursive descent of the tree
goes deeper and deeper until the maximum path length is reached. At that point an
error is returned. For example, if you used Windows Explorer to search for files in
such a cyclic directory, the same files show up repeatedly.
The cifs.symlinks.cycleguard option controls whether symbolic links that
might include a directory higher in the same tree are followed.
To eliminate the possibility of cyclic directory structures, make sure that the
cifs.symlinks.cycleguard option is On, which is the default, with the following
command:
options cifs.symlinks.cycleguard on
If you use symbolic links having dot or dot-dot components and want the filer to fol-
low the links, set the cifs.symlinks.cycleguard option to Off with the following
command:
options cifs.symlinks.cycleguard off
When you list the contents of a directory, symbolic links that are valid references to
files or directories are listed as if the target of the symbolic link existed in the direc-
tory. If the symbolic link cannot be expanded, it still looks like a file in a directory
listing; however, any attempt by an application to open the link results in an access
error.
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The filer, along with the MS-DOS® operating system and Windows, supports a per-file
read-only bit that reflects whether a file is writable or read-only. This bit applies only to
files and not to directories. NFS has no protocol operations that know about the per-
file read-only bit. However, some software, when used both by NFS clients on UNIX
systems and by CIFS clients on Windows systems, requires that the read-only bit
reflects whether the file is writable.

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The following list describes how NFS treats the read-only bit:
Any file with the read-only bit turned on is treated, for all NFS operations, as if it
had no write permission bits turned on.
If a file has at least one write permission bit turned on and an NFS client turns off
all write permission bits, the filer turns on the read-only bit for that file. As