On dump one uses one or more --ext-mount-map 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.
On restore one uses the same --ext-mount-map 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.
v3:
* Added documentation
* Added RPC bits
* Changed option name into --ext-mount-map
* Use colon as key and value separator
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Nowadays this routine is mainly used for getting an
fd, rather than keeping one for future reference.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This patch removes the global mntinfo_tree and collect_mount_info where
it was constructed. The mntinfo list is filled from dump_mnt_ns,
rst_collect_local_mntns, collect_mnt_namespaces and read_mnt_ns_img.
A mountinfo entry contains a reference on a proper ns_id entry, so
we cau use mnt_id to look up a proper mount namespace.
v2: remove trash after rebasing.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Kernels before 3.15 doesn't show mnt_id and mnt_id isn't saved in
images, if mntns isn't dumped.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
On restore all mount namespaces are restored in the root mntns and
sub-namecpeaces are restored in temorary places.
This function allows to get paths to these places.
It will be used in open_remap_ghost(), because it's called in the root
task, when other tasks are not forked yet.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
We are going to support nested mntns, so the global mntinfo_tree
variable are useless and information about tree should be connected
to a proper namespace.
But when we don't dump mntns, we need to collect mounts for the current
mntns.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
We are going to support nested mount namespaces and each NS has own
tree. The mount tree is used for checking that a file is reachable.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Known issue:
* currently only namespaces with the same root is supported
* nested namespaces can be dumped and restored only if the root task
has own mount namespace.
All nested namespaces are restored in a root namespace in temporary
directories. All mount points restored in one tree and then they are
divided into namesaces.
The task with minimal pid for each namespaces unshared mntns and
then it makes pivot_root in a proper temporary directory. All other
tasks makes setns to enter into a mount namespace of the task with
minimal pid.
v2: clean up
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
All non-root namespaces will be restored as sub-trees of the root tree.
This patch adds helpers to create a temporary directory and mount tmpfs
in it, then create directories for each non-root mount namespace.
tmpfs is quite useful here to simplify destroying this construction,
we don't need to unmount each namespace separately.
v2: add a comment why MNT_DETACH is not dangerous here
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
It's already used for dumping files and it will be used for restoring,
so it should be service fd to avoid intersection with restored
descriptors.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Instead of scanning btrfs subvolumes (which can be even unaccessbile
if mount point lays on directory instead of subvolume itself) we use
path resolving feature here -- once we need to figure out if some
device number need to be altered up to mount point (as we know stat()
called on subvolume returns st_dev for subvolume itself, but not
one that associated with a superblock and shown in /proc/self/mountinfo
output).
This as well implies that we need to check if device number for ghost
files are to be updated to match mountinfo, thus we use phys_stat_resolve_dev
helper here.
After this patch the previously merged btrfs engine is no longer needed
(at least it seems so) and can be dropped.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This routine is aimed to find a mount point on which
the path passed as argument is laying on. We walk over
all mount points and see which one is matching.
Once found (in worst case it will be a root mount point
so function is never failing) we're checking if this is
btrfs and then return subvolume0 device id.
See commit 921cf873f3
for details what the hell we're doing here.
v2: rewrite mount_resolve_path w/o recursion
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
For paths resolution we will need mount tree to be parsed
and built, but it's not that simple -- the current code
implies that once parsed the tree must not be re-parsed
again, so we pass @parse argument from a caller: if a task
we're restoring do not use mount namespace, we should parse
mount tree early, otherwise defer this action until mount
tree is read from the image.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This helper serves to hide fs specifics (in particular
btrfs) thus the caller won't need the details.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
We really have a mess of extern/non-extern declaration
of functions in our headers. Always use extern for
unification purpose.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
We are going to replace pid on id in names of image files. The id is
uniq for each namespace, so it's more convient, if image files are
opened per namespace.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
We have generic do_pb_show() call and tons of show_foo
routines, that just call one with proper args. Compact
the code by putting the args into array and calling
the do_pb_show() in one place.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Information about mount points is used for dumping fanotify.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
These are structs that (now) tie together ns string
and the CLONE_ flag. It's nice to have one (some code
becomes simpler) and will help us with auto-namespaces
detection.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
We will need to lookup mount points by mount id
and device for fanotify restore.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Make them look like __CR_<smth>_H__ with
sed -e '1,2s/#\(ifndef\|define\) _\?_\?\(CR_\)\?/#\1 __CR_/' -e '1,2s/_H_\?_\?.*$/_H__/'
on every header file.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
We need to dump content of some fs like binfmt_misc, tmpfs, ... To facilitate
this the existing list of filesystems is turned into an array of structures
with dump and restore callbacks. Each FS may declare them they need.
v2: rework encode/decode_fstype not to do it twice.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
The option is -r|--pivot-root and an argument is a path to new root.
A root task will make pivot_root. LXC CT does that, so we need that
for restoring.
v2: s/pivot-root/root/
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
If we dump tasks with mntns, we should look at pathes from point of a mntns root.
Now we support a situation when a root of an init task has the same root as the
mntns root, because we have not another way to get a root of mntns.
A path to an unix socket is copied, because the origin copy will be gone
out from the function, where it was created.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Namespace restore goes in two steps -- first, clean old mountpoints
(except root) that are left after clone(CLONE_NEWNS) call. Next,
repopulate the namespace with new mountpoints (except root) read
from the image file.
This patch adds the skeleton for the above -- reading the mountpoints
from current proc and image and calling for mount/umount. The real
action will come in further patches.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
v2:
- open_mount is cleaned up
- byte-stream hex conversion remains untouched since
strtol is flipping numbers to LE manner
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
At moment only open_mnt_root is there, which is
needed for inotify restore.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
