Let's use latest lvm2 sources to compile the libdevmapper library.
Initial reason for compiling devmapper lib from sources was a need to
have the static version of the library at hand, in order to build
the static dockerd, but note that the same headers/solib are used
for dynamic build (dynbinary) as well.
The reason for this patch is to enable the deferral removal feature.
The supplied devmapper library (and headers) are too old, lacking the
needed functions, so the daemon is built with 'libdm_no_deferred_remove'
build tag (see the check in hack/make.sh). Because of this, even if the
kernel dm driver is perfectly able to support the feature, it can not
be used. For more details and background story, see [1].
Surely, one can't just change the version number. While at it:
- improve the comments;
- remove obsoleted URLs;
- remove s390 and ppc configure updates that are no longer needed;
- use pkg-config instead of hardcoding the flags (newer lib added
some more dependencies);
[1] https://github.com/moby/moby/issues/34298
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
1. devmapper_wrapper_{,no_}deferred_remove.go:
Comments about LibraryDeferredRemovalSupport were very totally
misleading to me. This thing has nothing to do with either static
or dynamic linking (but with build tags). Fix the comment accordingly.
2. devmapper.go:
Reveal the source of those magic device* constants.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Deferred reove functionality was added to library later. So in old version
of library it did not report deferred_remove field.
Create a new function which also gets deferred_remove field and it will be
called only on newer version of library.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
A lot of time device mapper devices leak across mount namespace which docker
does not know about and when docker tries to deactivate/delete device,
operation fails as device is open in some mount namespace.
Create a mechanism where one can defer the device deactivation/deletion
so that docker operation does not fail and device automatically goes
away when last reference to it is dropped.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
