By default, if a user requests a bind mount it uses private propagation.
When the source path is a path within the daemon root this, along with
some other propagation values that the user can use, causes issues when
the daemon tries to remove a mountpoint because a container will then
have a private reference to that mount which prevents removal.
Unmouting with MNT_DETATCH can help this scenario on newer kernels, but
ultimately this is just covering up the problem and doesn't actually
free up the underlying resources until all references are destroyed.
This change does essentially 2 things:
1. Change the default propagation when unspecified to `rslave` when the
source path is within the daemon root path or a parent of the daemon
root (because everything is using rbinds).
2. Creates a validation error on create when the user tries to specify
an unacceptable propagation mode for these paths...
basically the only two acceptable modes are `rslave` and `rshared`.
In cases where we have used the new default propagation but the
underlying filesystem is not setup to handle it (fs must hvae at least
rshared propagation) instead of erroring out like we normally would,
this falls back to the old default mode of `private`, which preserves
backwards compatibility.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Upstream-commit: 589a0afa8cbe39b6512662fd1705873e2d236dd0
Component: engine
Prevent the docker daemon from mounting the created network files over
those provided by the user via -v command line option. This would otherwise
hide the one provide by the user.
The benefit of this is that a user can provide these network files using the
-v command line option and place them in a size-limited filesystem.
Signed-off-by: Stefan Berger <stefanb@us.ibm.com>
Upstream-commit: 6bd389b9db38eaf4ce2b9cc0cf5024f8450504ef
Component: engine
