Based on work done by Cyrill Corcunov (many thanks for that).

In this commit we implement c/r for files which have opened
/proc/$pid/ns/$ids entries.

The idea is rather simple one

Checkpoint
==========

- Check if the file name is the one of known to be ns ref
- If match then write protobuf entry

Restore
=======

- Read all ns entries from the image
- When criu tries to open one we lookup over process
  tree to figure out which PID should be used in path
  and then just open it
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

[ xemul: rename pb.cflag -> pb.ns_cflag ]
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

This will be needed for fast parsing of procfs ns references.

[ xemul: Add user_ns_desc here ]
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

To be able to dump procfs namespace entries we will need to
analyze the link name first and then figure out if the file
referred indeed a procfs entry or it's plain regular file.

This means we read link early, and to escape double reading
of same link, once we read it we remember it in fd_parms
structure which we pass to dump_one_reg_file.

Still the dump_one_reg_file is not solely used from inside
of dump_one_file, but from a number of other places (fifo,
special files) where fd_parms is filled only partially
and fill_fd_params is not even called. Thus dump_one_reg_file
must be ready for such scenario and read the link name by own
if the caller has not provided one.

To achieve all this we do

 - extend fd_parms structure to have a reference on a new
   fd_link structure, thus if caller already read the link
   name it might assign the reference and call for dump_one_reg_file

 - tune up dump_one_reg_file to fill own copy of fd_link
   structure if the caller has not provied one

  [ xemul: Added const to fill_fdlink arg ]
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

struct fd_parms is reused for two calls, so don't
forget to initialize it before dump_one_reg_file
call.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

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

All this sits under config option, so we shouldn't try
to read/write them in this case. What to do if they are
in different on/off state on src/dst kernels is an open
question :\
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

The soft-dirty API has changed slightly -- now the bit in
question _is_ in pagemap file (not pagemap2) but to see it
we have to reset soft-dirty for anyone first.

Teach the kerndat soft-dirty checker this fact. The actual
pagemap reading code already knows select pagemap/pagemap2
file itself.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

The option -p is used for testing page server
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

without this patch, fd will not be freeed

* Changelog from v1:
	* just free fd, no crt.ids
Signed-off-by: Libo Chen <libo.chen@huawei.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

when pb_read_one_eof faild, we should close fd
Signed-off-by: Libo Chen <libo.chen@huawei.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

when mntns_collect_root->readlinkat call faild, we should close pdf
Signed-off-by: Libo Chen <libo.chen@huawei.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

when is_blocked is seted, we should free file_lock
Signed-off-by: Libo Chen <libo.chen@huawei.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Libo Chen <libo.chen@huawei.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Currsntly this affects nothing, but xfer close should be called.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

If we have empty pagemap, the page server receives no
IO-s for one and doesn't create image file. Intoroduce
the OPEN command to say to page server, that we're about
to xfer and image so it can prepare.

https://bugzilla.openvz.org/show_bug.cgi?id=2584Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

First of all, 4 bits are not enough for type (shmem pagemap's is
28, which is 5 bits). Plus the encode trimmed bits from the id.

https://bugzilla.openvz.org/show_bug.cgi?id=2584Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

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

Since commit 43ce038e -t is not required for restore,
plus a warning is printed if it is used. Let's remove
-t from criu restore in all test cases.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

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

cr-check.c for some reason got x bit O_o
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Will be needed for parasite code.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

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

pages_scanned -- the amount of pages criu looked at for decision
pages_skipped_parent -- the amount of pages that were skipped, due to
                        they are present in parent image
pages_writted -- the amount of pages criu transfered into image
Signed-off-by: Pavel Emelyanov <xemul@parallels.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>

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

Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

-D is used for dump and restore, i.e. to read and write image files,
depending on the command, so let's put a read/write-neutral description.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

A couple of fixes related to the fact.

This is an addition to commit 43ce038eSigned-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

This patch

1. Replaces using argv[0] with criu literal. Using argv[0] is bad
because it can be a relative path, and it can be not "criu" but
say a symlink pointing to criu.

2. Reformats the source to print basic help test in justone call to
pr_msg(), same as commit 6ea0e002 did for extended help, for same
reasons: having it this way is easier to do further edits.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

I'll need to modify this header so before anything
else lets beautify it

 - drop struct pstree_item declaration it's already in pstree.h
 - move struct cr_options to top
 - align members of struct ns_desc
 - move externs to top
 - add argument name to try_show_namespaces
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

#PSBM-19883
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

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

The "*:<fmt>" describes format for everyone else in pretty.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>