GNU Info

(am-utils.info)Mounting a Volume

---

Next: Automatic Unmounting Prev: Operational Principles Up: Overview

---

Enter node , (file) or (file)node

Mounting a Volume
=================

   Each automount point has a corresponding mount map.  The mount map
contains a list of key-value pairs.  The key is the name of the volume
to be mounted.  The value is a list of locations describing where the
filesystem is stored in the network.  In the source for the map the
value would look like

     location1  location2  ...  locationN

   Amd examines each location in turn.  Each location may contain
"selectors" which control whether Amd can use that location.  For
example, the location may be restricted to use by certain hosts.  Those
locations which cannot be used are ignored.

   Amd attempts to mount the filesystem described by each remaining
location until a mount succeeds or Amd can no longer proceed.  The
latter can occur in three ways:

   * If none of the locations could be used, or if all of the locations
     caused an error, then the last error is returned.

   * If a location could be used but was being mounted in the
     background then Amd marks that mount as being "in progress" and
     continues with the next request; no reply is sent to the kernel.

   * Lastly, one or more of the mounts may have been "deferred".  A
     mount is deferred if extra information is required before the
     mount can proceed.  When the information becomes available the
     mount will take place, but in the mean time no reply is sent to
     the kernel.  If the mount is deferred, Amd continues to try any
     remaining locations.

   Once a volume has been mounted, Amd establishes a "volume mapping"
which is used to satisfy subsequent requests.