writing to netdev configuration at non zero offset won't be supported:

```
[  301.431638] netns-dev wrote to accept_local when file position was
not 0! This will not be supported in the future. To silence this
warning, set kernel.sysctl_writes_strict = -1
```

v2: fix compilation

Sorry, please don't consider v1.
Signed-off-by: Pavel Tikhomirov <ptikhomirov@odin.com>
Acked-by: Andrew Vagin <avagin@odin.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Currently this doesn't matter correctness-wise (with or without the
previous changes), but imho collect_mntinfo() needs a cleanup. We
should not return with ->mntinfo_list pointing to the freed memory
on failure, even if currently this failure is fatal and nobody will
ever use this pointer.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

This check was added by commit aebfabb5 "mnt: add --ext-mount-map
auto option", but unless I am totally confused it actually belongs
to the (already reverted) 246367e4 "add walk_all flag to
walk_namespaces".

Remove it. It is no longer needed and it was very unobvious.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

We no longer need to populate ext_ns->mnt.mntinfo_list until
resolve_external_mounts(). We can rely on find_ext_ns_id() which
does collect_mntinfo() on demand.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Currently we rely on the fact that ->mntinfo_list was already
collected by walk_namespaces(walk_all => true), but we are going
to change this.

This patch simply adds collect_mntinfo(ns) into find_ext_ns_id() if
->mntinfo_list == NULL. This is all we need for this ns_id if it was
not initialized by collect_mnt_namespaces().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Preparation. Extract the "search the criu's mount info" code from
resolve_external_mounts() into the new simple helper, find_ext_ns_id().

Also change resolve_external_mounts() to check ext_ns == NULL rather
than !opts.autodetect_ext_mounts. Cosmetic.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

do_new_mount() clears MS_SHARED but this is not enough. It should clear
all bits processed in restore_shared_options().

The patch also adds MS_UNBINDABLE to MS_CHANGE_TYPE_MASK even if it is
not currently used. Just to match the kernel's do_change_type() check.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Only if inventory says it's v1 -- switch to old scheme.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Doing it at inventory write time is too late. Other than this, inventory
isn't created for pre-dump, thus this one always generates v1 images.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

tested under Gentoo Linux, with sys-kernel/linux-headers-3.19 installed
"struct user_pt_regs" is defined at file /usr/include/asm/ptrace.h
Signed-off-by: Yixun Lan <yixun.lan@gmail.com>
Reviewed-by: Christopher Covington <cov@codeaurora.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Ruslan Kuprieiev <rkuprieiev@cloudlinux.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

These images have common magic in front of per-image one. With
this we have 3 "types" of images -- inventory (head), other
images, service files. The latter would be stats (not an image,
just happen to be in PB format) and irmap cache (not an image
again, just auxiliary thing which is in PB for convenience).

Since inventory file is the first one we read on restore it's
OK to set the global "new images" flag there. Dump (write) is
always in new format.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Ruslan Kuprieiev <rkuprieiev@cloudlinux.com>
Acked-by: Andrew Vagin <avagin@odin.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Ruslan Kuprieiev <rkuprieiev@cloudlinux.com>
Acked-by: Andrew Vagin <avagin@odin.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>

collect_mnt_namespaces() returns with ret=0 if resolve_external_mounts()
fails.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

We can simply overwrite the dot symbol right after the kernel reports
it to us.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

resolve_source() insists on kdev_major() == 0, and this makes sense.
However, at least FSTYPE__AUTO can try to use mi->source as a block
device and pray it will work.

[ Also bout this change from Oleg:

Let me send another (last) functional change before the promised
cleanups we discussed.

To remind, without this patch I still can't dump/restore /home and
/boot on my testing machine. --enable-fs xfs "works" in a sense that
"dump" succeeds. But "restore" fails.

However. Lets forget this for the moment. To me resolve_source() looks
just wrong. Sure, I agree, it is not safe to blindly use mi->source if
kdev_major() != 0. But this means that we should not have dumped this
mountpoint, simply because we can't restore it.

Yes, currently this works because fstypes[] contains only the diskless
filesystems, but still.

So this probably needs more cleanups too, and this patch doesn't make
this logic look better.

To me, we should do something like

	static char *resolve_source(struct mount_info *mi)
	{
		if (kdev_major(mi->s_dev) == 0)
			/*
			 * Anonymous block device. Kernel creates them for
			 * diskless mounts.
			 */
			return mi->source;

		if (mi->fstype->code != FSTYPE__AUTO) {
			pr_err("OOPS! something is wrong!!!\n");
			return NULL;
		}

		// OK, this is FSTYPE__AUTO, it should "just work"
		// by definition. Or the user should blame himself.

		struct stat st;

		if (stat(mi->source, &st) || !S_ISBLK(st.st_mode) ||
		    major(st.st_rdev) != kdev_major(mi->s_dev) ||
		    minor(st.st_rdev) != kdev_minor(mi->s_dev))
			pr_warn("Hmm, can't verify blkdev. Lets see if mount will work...\n");

		return mi->source;
	}

But this patch only does a minimal change to make FSTYPE__AUTO work
with blkdev.

]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

It mostly reuses the infrastructure for plugin testing.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

The existing set of shell scripts do hard-to-debug things and mess
with the root filesystem. We can make it better.

First, not to play with the system / the process that will be run in
a new mount namespace is statically compiled .c file. And this "init"
does a very simple thing -- waits for SIGTERM and check that the
given filepath contains the given string.

Second, the namespace's root will be some subdir, instead of system
/ bind-mount-ed into a subdir. This makes it easier to keep things
together and makes 100% sure the external bind mount cannot be
accessed by custom path.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

This option enables external (slave) bind mounts to be resolved.

v2: don't always assume that when the master id matches, the mounts match
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

With this flag, external shared bind mounts are attempted to be resolved
automatically.

v2: don't always assume when the sharing matches that the mount matches
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

When this option is specified, if an external (private) bind mount is not
specified by --ext-mount-map KEY:VAL then it is attempted to be resolved
automatically.

v2: introduce find_best_external_match, which looks for the best match based on
    sharing/slave ids; don't try to resolve fsroot_mounted() mountpoints
v3: get rid of really_collect_self_mounts
v4: get rid of fsroot_mounted() check when autodetecting external mounts
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Finally add --enable-fs option to specify the comma separated list of
filesystem names which should be treated as FSTYPE_AUTO.

Note: obviously this option is not safe, use at your own risk. "dump"
will always succeed if the mntpoint is auto, but "restore" can fail or
do something wrong if mount(src, mountpoint, flags, options) can not
actually "just work" as FSTYPE_AUTO logic expects.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Add the new mnt_entry->fsname member and change dump_one_mountpoint()
to save pm->fstype->name if fstype == FSTYPE__AUTO.

Change collect_mnt_from_image() to pass this ->fsname to decode_fstype()
which falls back to __find_fstype_by_name(fsname, true) if FSTYPE__AUTO.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Simple preparation to simplify the review of the next patch. Turn
find_fstype_by_name(name) into __find_fstype_by_name(name, force_auto)
and reimplement find_fstype_by_name() as a trivial wrapper on top.

This allows "restore" to specify that this particular fsname was treated
as FSTYPE__AUTO by "dump".
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

The comment in find_fstype_by_name() says:

	just mounting anything is wrong

and this is true in general, but:

	almost every fs has its own features

this is not true in a sense that a lot of supported filesystems do not
need any special processing: FSTYPE__PROC, FSTYPE__SYSFS, and more. More
importantly, this logic does not allow to spicify from the command line
that (say) currently unsupported hugetlbfs can "just work", do_new_mount()
should only pass the right name/options.

This patch adds the new FSTYPE__AUTO code, find_fstype_by_name(name) adds
the new entry if fsname_is_auto(name) returns true. We do not care that
different fstype's can have the same FSTYPE__AUTO code, fstype->code has
no meaning unless we need to do something special with this fs, but in
this case it should not be FSTYPE__AUTO by definition.

Note: currently find_fstype_by_name() just returns true, it is obviously
pointless to "dump" until we teach "restore" to handle FSTYPE__AUTO.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Preparation. Enlarge fstypes[] to make it possible to add the new
fstype's dynamically.

This means ths find_fstype_by_name() and decode_fstype() need the
additional ->name == NULL check to terminate the search.

Also change them to start with "i == 1", we rely on the fact that
fstypes[0] is FSTYPE__UNSUPPORTED anyway.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

1. If a fuse connection is present, but there are no fuse mounts of that type
   in the mount namespace, don't refuse to dump.
2. If there are mounts of that type in the container but they are external,
   we're going to bind them anyway, so there's no fuse-specific things that
   need to be done, so it is safe to dump.

v2: check that the fstype is fuse as well
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

we don't need this check as just after it we have:
if (ret)
	break;
which safely unpackes nde, and closes nlsk and img in case of error

ps: sorry for inconveniences caused by my patchset
Signed-off-by: Pavel Tikhomirov <ptikhomirov@odin.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Somehow _sys_ token sneaked into __NR term. Drop it off
to be close to kernel's representation.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

check it for default/lo, test values for config options are randomly
generated and restricted by rand_limit

changes:
v2: make for all config options, avoid use of "system".
v3: err->fail, run in own set of namespaces, add random,
check not all options.
v4: use all options because test is run in net-namespace,
use ARRAY_SIZE macro
v5: check fscanf and snprintf return values properly
Signed-off-by: Pavel Tikhomirov <ptikhomirov@parallels.com>
Acked-by: Andrew Vagin <avagin@odin.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

because namespace default options are set before devices creation,
devices will gain default options(except lo, which is created with ns).
Signed-off-by: Pavel Tikhomirov <ptikhomirov@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Pavel Tikhomirov <ptikhomirov@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

restore order:
1. default
2. all
3. devices
Signed-off-by: Pavel Tikhomirov <ptikhomirov@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Pavel Tikhomirov <ptikhomirov@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>