[CRIU] [RFC][PATCH 0/3] Proposal for native (w/o plugins) support for external bind mounts v2

[Andrew Vagin]

Looks good to me.

I would like to have a test for this option.

On Thu, Jun 05, 2014 at 07:10:43PM +0400, Pavel Emelyanov wrote:
> So, the 1st attempt with modifying original mount points roots is
> not working since the paths we see in /proc and dump are relative
> to the FS's root, not relative to global (well, CRIU's) root.
> 
> That said, we can try to go another route and here it is.
> 
> On dump we use one or more --ext-mount option with A=B arguments.
> A denotes a mountpoint (as seen from the target mount namespace)
> criu dumps and B is the string that will be written into the
> image file instead of the mountpoint's root. E.g. if we have a
> /foo/bar bind mounted into container under /x name, then the
> --ext-mount /x=foobar option will tell criu, that /x is a mount
> point with external source and it should write "foobar" into image
> instead of the path read from /proc.
> 
> On restore we use the same --ext-mount option(s) with similar
> A=B arguments, but this time criu treats A as string from the
> image's root field (foobar in the example above) and B as the
> path in criu's mount namespace the should be bind mounted into
> the mountpoint.
> 
> For example, let's again imagine we have /foo/bar bind mounted
> into container under /x name and /foo/bar is inaccessible from
> this container.
> 
> On dump we say --ext-mount /x=foobar and mountpoints.img will
> contain a mountpoint with root=foobar and mountpoint=/x. On restore
> we use --ext-mount foobar=/foo2/bar option. This will result the
> /foo2/bar from criu's namespace get bind-mounted to /x inside the
> container we restore.
> 
> 
> Thanks,
> Pavel
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