#63 Can't mount below /dev on multiple nodes

closed-fixed
nobody
Filesystem (49)
5
2008-01-02
2004-06-30
No

This was seen when attempting to do profiling on
multiple nodes.

The opcontrol command does the following:

mount -t oprofilefs nodev /dev/oprofile >/dev/null

Since this adds the entry to /etc/mtab, a subsequent
node can't do another mount even though /dev is unique
for each node.

While we could simply add a "-n" to the opcontrol
script, this doesn't solve the general problem. We
could change the mount command to replace /dev
directory specification to /cluster/nodeX/dev. This
would allow every node to mount below /dev, because the
mount command would fix things to reflect the SSI
kernel notion of what /dev is.

I believe that this change would improve our
application compatibility.

Discussion

  • David Zafman

    David Zafman - 2004-07-01

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    The fix for this is harder than I first thought. First if
    we get mount to mount on /cluster/nodeX/dev instead of /dev,
    the mount point won't be seen below /dev and vice versa.
    This is due to the bind mount nature of /dev.

    Also, since /dev is controlled by the node context, the
    mount system call currently only works for local node, even
    though we might want to function ship to the node context node.

    It is critical that the translation /dev ->
    /cluster/nodeX/dev at user level matches the results of the
    mount() system call in terms of which /dev has the mount
    actually on.

     
  • Roger Tsang

    Roger Tsang - 2008-01-02

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    user_id=1246761
    Originator: NO

    This bug is resolved in SSI-1.9. In SSI-1.9 /dev/X resolves to /cluster/nodeX/dev. mtab /dev/X entries are unique for each node.

     
  • Roger Tsang

    Roger Tsang - 2008-01-02
    • status: open --> closed-fixed
     

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