[CRIU] [PATCH 0/2] C/R of mandatory mountpoints

Pavel Emelyanov xemul at virtuozzo.com
Thu Jul 21 06:56:17 PDT 2016


On 07/12/2016 05:51 PM, Dmitry Safonov wrote:
> Support mandatory mounted mountpoints with excluseive locks.

I doubt one patch is enough :)

Consider we restore a mand-mounted sb, we mount it with MS_MANDLOCK, then
restore a file lock on it, then try to open this file for some other reason.
The criu restore would block (or abort with error).

So either we somehow make full support for mandlocks, or (since we know
the problem exists) explicitly abort dumping these guys.

-- Pavel

> The patches set dumps content of mountpoint by remounting without
> `mand` option (when tree is freezed).
> So, the only possible mess is when _out of tree process_ will try
> to access file on dumping stage. But, I guess, that's what
> one can expect with --file-locks option.
> 
> https://jira.sw.ru/browse/PSBM-41363
> 
> Dmitry Safonov (2):
>   mount: support mandatory locked mountpoints
>   test: add mandatory-lock test
> 
>  criu/mount.c                       | 130 +++++++++++++++++++++++++++++++++++--
>  criu/proc_parse.c                  |   2 +-
>  test/zdtm/.gitignore               |   1 +
>  test/zdtm/static/Makefile          |   3 +-
>  test/zdtm/static/file_locks06.c    | 110 +++++++++++++++++++++++++++++++
>  test/zdtm/static/file_locks06.desc |   1 +
>  test/zdtm/static/file_locks06.opts |   1 +
>  7 files changed, 242 insertions(+), 6 deletions(-)
>  create mode 100644 test/zdtm/static/file_locks06.c
>  create mode 100644 test/zdtm/static/file_locks06.desc
>  create mode 100644 test/zdtm/static/file_locks06.opts
> 



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