[CRIU] [PATCH 00/39] Restore nested mount namespaces (v6)

[Andrey Vagin]

Systemd is able to execute a service in a new mount namespace.
It's used by Fedora and probably will be used in RHEL7.

All nested mount namespaces are restored as sub-trees of the root
namespace. A namespace is restored by a task with minimal pid in this
namespace. The task unshares mount namespace and makes pivot_root in a
proper sub-tree. All other task from the namespace attaches to the
namespace by calling setns().

v2: write more descriptive comments
v3: don't leak fd on error path in dump_mnt_ns()
v4: fix Pavel's comments.
v5: don't use the set_exec_env pattern.
v6: fix Pavel's comments

Andrey Vagin (38):
  mount: close old descriptor in mntns_collect_root
  mounts: initialize root before dumping mount namespace
  mounts: allow to customize root path for cr_pivot_root (v2)
  restore: add mount id-s in the ns_ids list (v4)
  mounts: mark local root-s in the list of mount points (v2)
  mounts: connect sub-root to the main root
  mounts: share one root for all namespaces
  mount: read information about all mount namespaces
  mounts: create a temporary directory for restoring non-root mntns (v2)
  crtools: restore nested mount namespaces (v2)
  mount: allow to dump and restore nested mount namespaces (v3)
  criu: rename current_ns_mask to root_ns_mask (v2)
  zdtm/mountpoints: test nested mount namespaces
  namespaces: dump mount namespaces before tasks (v2)
  zdtm: mark all mounts as private for one call
  zdtm: reexec the mountpoints test in a target mntns
  files: save mnt_id on fd_param
  files: save mnt_id for reg files
  files-ids: generate id-s accoding with mnt_id, st->st_dev and
    st->st_ino
  restore: close PROC_FD_OFF before calling sigreturn
  mount: return descriptor from mntns_collect_root
  mount: save mount tree for each namespace
  mount: move dump_mnt_namespaces in mount.c
  mount: separate collect_mnt_ns from dump_mnt_ns
  resotre: collect mounts of current mntns
  mount: set nsid for each mount point
  mounts: mntns_collect_root in __open_mountpoint
  irmap: mntns_collect_root in irmap_lookup
  mount: add a function to get a temporary root for mntns
  mount: use per-ns list of mount-points in clean_mnt_ns and free_mnt_ns
  check: collect mounts of the current mntns
  mount: prepare to work without mnt_id
  restore: set buildinfo_tree for each mount namespace
  mount: use per-namespace mntinfo_tree (v2)
  mount: don't open the same root twise
  zdtm: check opened files in a second mntns
  check: check the mnt_id field in fdinfo
  mount: prevent dumping nested mount namespace without mnt_id in fdinfo

 cr-check.c                          |  38 ++-
 cr-dump.c                           |  76 +++--
 cr-restore.c                        |  51 +++-
 file-ids.c                          |  32 ++-
 files-reg.c                         |  81 ++++--
 files.c                             |   3 +-
 include/file-ids.h                  |   5 +-
 include/files.h                     |   2 +
 include/mount.h                     |  20 +-
 include/namespaces.h                |  13 +-
 include/proc_parse.h                |   6 +-
 include/pstree.h                    |   2 +
 include/syscall-types.h             |   3 +
 irmap.c                             |   4 +
 mount.c                             | 547 +++++++++++++++++++++++++++++-------
 namespaces.c                        |  59 +++-
 net.c                               |   4 +-
 proc_parse.c                        |   4 +-
 protobuf/regfile.proto              |   1 +
 pstree.c                            |  29 +-
 sk-tcp.c                            |   8 +-
 sk-unix.c                           |  13 +-
 sockets.c                           |   2 +-
 test/zdtm.sh                        |   1 +
 test/zdtm/lib/test.c                |  18 +-
 test/zdtm/live/static/mountpoints.c | 113 ++++++--
 tun.c                               |   2 +-
 27 files changed, 894 insertions(+), 243 deletions(-)

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1.8.5.3