[PATCH v2 0/2] enhance NFSv4.2 SSC to delay unmount source's export.

From: Dai Ngo <dai.ngo@oracle.com>
To: olga.kornievskaia@gmail.com
Cc: linux-nfs@vger.kernel.org, trondmy@hammerspace.com,
	bfields@fieldses.org, chuck.lever@oracle.com
Subject: [PATCH v2 0/2] enhance NFSv4.2 SSC to delay unmount source's export.
Date: Fri,  2 Apr 2021 19:30:29 -0400	[thread overview]
Message-ID: <20210402233031.36731-1-dai.ngo@oracle.com> (raw)

Hi,

Currently the source's export is mounted and unmounted on every
inter-server copy operation. This causes unnecessary overhead
for each copy.

This patch series is an enhancement to allow the export to remain
mounted for a configurable period (default to 15 minutes). If the 
export is not being used for the configured time it will be unmounted
by a delayed task. If it's used again then its expiration time is
extended for another period.

Since mount and unmount are no longer done on each copy request,
this overhead is no longer used to decide whether the copy should
be done with inter-server copy or generic copy. The threshold used
to determine sync or async copy is now used for this decision.

-Dai

v2: fix compiler warning of missing prototype.