[CRIU] [PATCH 1/4] remap: add remap_type field and use it

[Tycho Andersen]

Hi Andrew,

On Mon, Sep 15, 2014 at 06:38:37PM +0400, Andrew Vagin wrote:
> Hi Tycho,
> 
> I looked at this error. I think we need smth like this:
> diff --git a/files-reg.c b/files-reg.c
> index 835911a..1d43b2f 100644
> --- a/files-reg.c
> +++ b/files-reg.c
> @@ -396,6 +396,7 @@ dump_entry:
>         rpe.orig_id = id;
>         rpe.has_remap_type = true;
>         rpe.remap_type = REMAP_TYPE__GHOST;
> +       rpe.remap_id = gf->id;
>  
>         return pb_write_one(fdset_fd(glob_fdset, CR_FD_REMAP_FPATH),
>                         &rpe, PB_REMAP_FPATH);
> 
> I don't investigate this issue carefully. The test passes with this
> patch. It may be usefull for you.
> 
> Thanks.

Yes, that seems to fix it. However, I ran into another bad race caused
by this patch, which means I need to update more stuff. Hopefully the
last version will come sometime tonight or tomorrow...

Tycho

> On Mon, Sep 15, 2014 at 06:08:48PM +0400, Andrew Vagin wrote:
> > [root at avagin-fc19-cr criu]# bash test/zdtm.sh  ns/static/cwd01
> > Execute zdtm/live/static/cwd01
> > ./cwd01 --pidfile=cwd01.pid --outfile=cwd01.out --dirname=cwd01.test
> > /root/git/criu/test
> > Dump 7563
> > Restore
> > Check results 7592
> > test/zdtm.sh: line 461: kill: (7592) - No such process
> > Unable to stop cwd01 (7592)
> > Test: zdtm/live/static/cwd01, Result: FAIL
> > ==================================== ERROR ====================================
> > Test: zdtm/live/static/cwd01, Namespace: 1
> > Dump log   : /root/git/criu/test/dump/static/cwd01/7563/1/dump.log
> > --------------------------------- grep Error ---------------------------------
> > ------------------------------------- END -------------------------------------
> > Restore log: /root/git/criu/test/dump/static/cwd01/7563/1/restore.log
> > --------------------------------- grep Error ---------------------------------
> > (00.048617)      1: Error (image.c:217): Unable to open ghost-file-0.img: No such file or directory
> > (00.048731) Error (cr-restore.c:1781): Restoring FAILED.
> > ------------------------------------- END -------------------------------------
> > ================================= ERROR OVER =================================
> > 
> > On Fri, Sep 12, 2014 at 07:43:28PM -0500, Tycho Andersen wrote:
> > > Maintain backwards compatibility for old images, but don't set the REMAP_GHOST
> > > bit going forward, only use the remap_type field.
> > > 
> > > Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
> > > ---
> > >  files-reg.c                    | 31 ++++++++++++++++++++++++-------
> > >  protobuf/remap-file-path.proto |  6 ++++++
> > >  2 files changed, 30 insertions(+), 7 deletions(-)
> > > 
> > > diff --git a/files-reg.c b/files-reg.c
> > > index 0ffce0e..835911a 100644
> > > --- a/files-reg.c
> > > +++ b/files-reg.c
> > > @@ -131,7 +131,6 @@ static int open_remap_ghost(struct reg_file_info *rfi,
> > >  	int ifd;
> > >  	char *root;
> > >  
> > > -	rfe->remap_id &= ~REMAP_GHOST;
> > >  	list_for_each_entry(gf, &ghost_files, list)
> > >  		if (gf->id == rfe->remap_id)
> > >  			goto gf_found;
> > > @@ -246,10 +245,29 @@ static int collect_one_remap(void *obj, ProtobufCMessage *msg)
> > >  	rfi = container_of(fdesc, struct reg_file_info, d);
> > >  	pr_info("Configuring remap %#x -> %#x\n", rfi->rfe->id, rfe->remap_id);
> > >  
> > > -	if (rfe->remap_id & REMAP_GHOST)
> > > -		ret = open_remap_ghost(rfi, rfe);
> > > -	else
> > > +
> > > +	if (!rfe->has_remap_type) {
> > > +		rfe->has_remap_type = true;
> > > +		/* backward compatibility with images */
> > > +		if (rfe->remap_id & REMAP_GHOST) {
> > > +			rfe->remap_id &= ~REMAP_GHOST;
> > > +			rfe->remap_type = REMAP_TYPE__GHOST;
> > > +		} else
> > > +			rfe->remap_type = REMAP_TYPE__LINKED;
> > > +	}
> > > +
> > > +	switch (rfe->remap_type) {
> > > +	case REMAP_TYPE__LINKED:
> > >  		ret = open_remap_linked(rfi, rfe);
> > > +		break;
> > > +	case REMAP_TYPE__GHOST:
> > > +		ret = open_remap_ghost(rfi, rfe);
> > > +		break;
> > > +	default:
> > > +		pr_err("unknown remap type %u\n", rfe->remap_type);
> > > +		goto out;
> > > +	}
> > > +
> > >  out:
> > >  	return ret;
> > >  }
> > > @@ -375,10 +393,9 @@ static int dump_ghost_remap(char *path, const struct stat *st,
> > >  		return -1;
> > >  
> > >  dump_entry:
> > > -	BUG_ON(gf->id & REMAP_GHOST);
> > > -
> > >  	rpe.orig_id = id;
> > > -	rpe.remap_id = gf->id | REMAP_GHOST;
> > > +	rpe.has_remap_type = true;
> > > +	rpe.remap_type = REMAP_TYPE__GHOST;
> > >  
> > >  	return pb_write_one(fdset_fd(glob_fdset, CR_FD_REMAP_FPATH),
> > >  			&rpe, PB_REMAP_FPATH);
> > > diff --git a/protobuf/remap-file-path.proto b/protobuf/remap-file-path.proto
> > > index faeb745..cb8568f 100644
> > > --- a/protobuf/remap-file-path.proto
> > > +++ b/protobuf/remap-file-path.proto
> > > @@ -1,4 +1,10 @@
> > > +enum remap_type {
> > > +  LINKED		= 0;
> > > +  GHOST 		= 1;
> > > +};
> > > +
> > >  message remap_file_path_entry {
> > >  	required uint32		orig_id		= 1;
> > >  	required uint32		remap_id	= 2;
> > > +	optional uint32		remap_type	= 3;
> > >  }
> > > -- 
> > > 1.9.1
> > > 
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