1) docker create / run / start: this would create a snapshot device and mounts it onto the filesystem.
So the first time GET operation is called. it will create the rootfs directory and return the path to rootfs
2) Now when I do docker commit. It will call the GET operation second time. This time the refcount will check
that the count > 1 (count=2). so the rootfs already exists, it will just return the path to rootfs.
Earlier it was just returning the mp: /var/lib/docker/devicemapper/mnt/{ID} and hence the inconsistent paths error.
Signed-off-by: Shishir Mahajan <shishir.mahajan@redhat.com>
For things that we can check if they are mounted by using their fsmagic
we should use that and for others do it the slow way.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
This makes sure fsdiff doesn't try to unmount things that shouldn't be.
**Note**: This is intended as a temporary solution to have as minor a
change as possible for 1.11.1. A bigger change will be required in order
to support container re-attach.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Right now there is no way to know what's the minimum free space threshold
daemon is applying. It would be good to export it through docker info and
then user knows what's the current value. Also this could be useful to
higher level management tools which can look at this value and setup their
own internal thresholds for image garbage collection etc.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Since the layer store was introduced, the level above the graphdriver
now differentiates between read/write and read-only layers. This
distinction is useful for graphdrivers that need to take special steps
when creating a layer based on whether it is read-only or not.
Adding this parameter allows the graphdrivers to differentiate, which
in the case of the Windows graphdriver, removes our dependence on parsing
the id of the parent for "-init" in order to infer this information.
This will also set the stage for unblocking some of the layer store
unit tests in the next preview build of Windows.
Signed-off-by: Stefan J. Wernli <swernli@microsoft.com>
Instead of implementing refcounts at each graphdriver, implement this in
the layer package which is what the engine actually interacts with now.
This means interacting directly with the graphdriver is no longer
explicitly safe with regard to Get/Put calls being refcounted.
In addition, with the containerd, layers may still be mounted after
a daemon restart since we will no longer explicitly kill containers when
we shutdown or startup engine.
Because of this ref counts would need to be repopulated.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Instead of implementing refcounts at each graphdriver, implement this in
the layer package which is what the engine actually interacts with now.
This means interacting directly with the graphdriver is no longer
explicitly safe with regard to Get/Put calls being refcounted.
In addition, with the containerd, layers may still be mounted after
a daemon restart since we will no longer explicitly kill containers when
we shutdown or startup engine.
Because of this ref counts would need to be repopulated.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
This change will allow us to run SELinux in a container with
BTRFS back end. We continue to work on fixing the kernel/BTRFS
but this change will allow SELinux Security separation on BTRFS.
It basically relabels the content on container creation.
Just relabling -init directory in BTRFS use case. Everything looks like it
works. I don't believe tar/achive stores the SELinux labels, so we are good
as far as docker commit.
Tested Speed on startup with BTRFS on top of loopback directory. BTRFS
not on loopback should get even better perfomance on startup time. The
more inodes inside of the container image will increase the relabel time.
This patch will give people who care more about security the option of
runnin BTRFS with SELinux. Those who don't want to take the slow down
can disable SELinux either in individual containers or for all containers
by continuing to disable SELinux in the daemon.
Without relabel:
> time docker run --security-opt label:disable fedora echo test
test
real 0m0.918s
user 0m0.009s
sys 0m0.026s
With Relabel
test
real 0m1.942s
user 0m0.007s
sys 0m0.030s
Signed-off-by: Dan Walsh <dwalsh@redhat.com>
Signed-off-by: Dan Walsh <dwalsh@redhat.com>
Adds support for the daemon to handle user namespace maps as a
per-daemon setting.
Support for handling uid/gid mapping is added to the builder,
archive/unarchive packages and functions, all graphdrivers (except
Windows), and the test suite is updated to handle user namespace daemon
rootgraph changes.
Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)
Finally here is the patch to implement deferred deletion functionality.
Deferred deleted devices are marked as "Deleted" in device meta file.
First we try to delete the device and only if deletion fails and user has
enabled deferred deletion, device is marked for deferred deletion.
When docker starts up again, we go through list of deleted devices and
try to delete these again.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Provide a command line option dm.use_deferred_deletion to enable deferred
device deletion feature. By default feature will be turned off.
Not sure if there is much value in deferred deletion being turned on
without deferred removal being turned on. So for now, this feature can
be enabled only if deferred removal is on.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Exists() and HasDevice() just check if device file exists or not. It does
not say anything about if device is mounted or not. Fix comments.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
TL;DR: check for IsExist(err) after a failed MkdirAll() is both
redundant and wrong -- so two reasons to remove it.
Quoting MkdirAll documentation:
> MkdirAll creates a directory named path, along with any necessary
> parents, and returns nil, or else returns an error. If path
> is already a directory, MkdirAll does nothing and returns nil.
This means two things:
1. If a directory to be created already exists, no error is returned.
2. If the error returned is IsExist (EEXIST), it means there exists
a non-directory with the same name as MkdirAll need to use for
directory. Example: we want to MkdirAll("a/b"), but file "a"
(or "a/b") already exists, so MkdirAll fails.
The above is a theory, based on quoted documentation and my UNIX
knowledge.
3. In practice, though, current MkdirAll implementation [1] returns
ENOTDIR in most of cases described in #2, with the exception when
there is a race between MkdirAll and someone else creating the
last component of MkdirAll argument as a file. In this very case
MkdirAll() will indeed return EEXIST.
Because of #1, IsExist check after MkdirAll is not needed.
Because of #2 and #3, ignoring IsExist error is just plain wrong,
as directory we require is not created. It's cleaner to report
the error now.
Note this error is all over the tree, I guess due to copy-paste,
or trying to follow the same usage pattern as for Mkdir(),
or some not quite correct examples on the Internet.
[v2: a separate aufs commit is merged into this one]
[1] https://github.com/golang/go/blob/f9ed2f75/src/os/path.go
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Export image/container metadata stored in graph driver. Right now 3 fields
DeviceId, DeviceSize and DeviceName are being exported from devicemapper.
Other graph drivers can export fields as they see fit.
This data can be used to mount the thin device outside of docker and tools
can look into image/container and do some kind of inspection.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
This will help with debugging as one could just do "docker info" and figure
out of deferred removal is enabled or not.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Fixes#9960
This adds the output of a "Backing Filesystem:" entry to `docker info`
to overlay, aufs, and devicemapper graphdrivers. The default list
includes a fairly complete list of common filesystem names from
linux/include/uapi/linux/magic.h, but if the backing filesystem is not
recognized, the code will simply show "<unknown>"
Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com>
There are a couple of drivers that swallow errors that may occur in
their Put() implementation.
This changes the signature of (*Driver).Put for all the drivers implemented.
Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>
Presenly the "Data file:" shows either the loopback _file_ or the block device.
With this, the "Data file:" will always show the device, and if it is a
loopback, then there will additionally be a "Data loop file:".
(Same for "Metadata file:")
Signed-off-by: Vincent Batts <vbatts@redhat.com>
Some graphdrivers are Differs and type assertions are made
in various places throughout the project. Differ offers some
convenience in generating/applying diffs of filesystem layers
but for most graphdrivers another code path is taken.
This patch brings all of the logic related to filesystem
diffs in one place, and simplifies the implementation of some
common types like Image, Daemon, and Container.
Signed-off-by: Josh Hawn <josh.hawn@docker.com>
