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* [9fans] What's a mounted channel?
@ 2021-05-29 20:36 Anonymous AWK fan via 9fans
  2021-05-30  5:11 ` [9fans] " Anthony Martin
  0 siblings, 1 reply; 2+ messages in thread
From: Anonymous AWK fan via 9fans @ 2021-05-29 20:36 UTC (permalink / raw)
  To: 9fans

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The comments on the #define lines and a commented out section of
stat(2) say (DM|QT)MOUNT indicates a mounted channel, what is this?

Also, why does exportfs fork and the kernel not send write on closed
pipe notes for mounted channels?

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* [9fans] Re: What's a mounted channel?
  2021-05-29 20:36 [9fans] What's a mounted channel? Anonymous AWK fan via 9fans
@ 2021-05-30  5:11 ` Anthony Martin
  0 siblings, 0 replies; 2+ messages in thread
From: Anthony Martin @ 2021-05-30  5:11 UTC (permalink / raw)
  To: 9fans

Anonymous AWK fan via 9fans <9fans@9fans.net> once said:
> The comments on the #define lines and a commented out section of
> stat(2) say (DM|QT)MOUNT indicates a mounted channel, what is this?
>
> Also, why does exportfs fork and the kernel not send write on closed
> pipe notes for mounted channels?

When you call mount(2), the mnt(3) driver attempts to
negotiate a conversation with the 9p server on the other
end of the supplied file descriptor. If the negotiation
is successful, the kernel sets a flag on the underlying
channel to restrict the set of operations available to
user space until the file descriptor is closed. If this
wasn't done, any reads, writes, or seeks would interfere
with the mount driver's ongoing 9p conversation.

Cheers,
  Anthony

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2021-05-29 20:36 [9fans] What's a mounted channel? Anonymous AWK fan via 9fans
2021-05-30  5:11 ` [9fans] " Anthony Martin

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