[CRIU] [PATCH 1/2] Quick patch for error when writing mem.lim default

[Pavel Emelyanov]

On 08/16/2014 12:08 AM, Garrison Bellack wrote:
> Pavel,
> 
> The patch above is completely independent from the missing properties patches that I split into 2. Please merge this as it fixes a completely unrelated bug. 

Ouch, sorry for confusion. Will merge one today.

> 
> On Fri, Aug 15, 2014 at 12:25 PM, Pavel Emelyanov <xemul at parallels.com <mailto:xemul at parallels.com>> wrote:
> 
>     On 08/15/2014 11:15 PM, Serge Hallyn wrote:
>     > That's going to be a painful thing to do item-by-item.  One way to address
>     > this - not urgent to do soon imo - would be to have the restart mark itself
>     > as failed, but not immediately halt;  have it write outa a file with all of
>     > the absent features;  Then the user edits that file marking all of the
>     > ok-to-ignore things, and passes it in with a '--ignore-absent <file>'
>     > argument, which criu then honors.
> 
>     I like the idea to postpone the failure and ask the caller what to do.
>     How about pushing the list of not found properties into the "post-restore"
>     script letting it decide what to do next? Or even introduce yet another
>     one, e.g. "cgroup-restore".
> 
>     > Just a thought, but it seems like the only sane way to handle it.
>     >
>     > Quoting Pavel Emelyanov (xemul at parallels.com <mailto:xemul at parallels.com>):
>     >> On 08/15/2014 08:54 PM, Ying Han wrote:
>     >>> Ping?
>     >>
>     >> We all agreed to commit the change that makes _dumping_ of absent properties
>     >> non-fatal (I'll do that soon). As far as writing is concerned -- it looks like
>     >> just ignoring the absence of properties from image dumps is not good as generic
>     >> solution. Instead, for restore we need some fine-grained control over which
>     >> properties to restore and which to ignore.
>     >>
>     >> Thanks,
>     >> Pavel
>     >>
>     >>
>     >>>
>     >>>
>     >>> On Wed, Aug 13, 2014 at 11:59 AM, <gbellack at google.com <mailto:gbellack at google.com> <mailto:gbellack at google.com <mailto:gbellack at google.com>>> wrote:
>     >>>
>     >>>     From: Garrison Bellack <gbellack at google.com <mailto:gbellack at google.com> <mailto:gbellack at google.com <mailto:gbellack at google.com>>>
>     >>>
>     >>>     When writing the system default for memory.limit_in_bytes (which is a LLONG_MAX)
>     >>>     the write fails. The number is equivalent to -1 (unlimited). So during dump,
>     >>>     store the number -1 instead.
>     >>>
>     >>>     Change-Id: Iafccc96bf5dbade763d7addaeda24194616e4d5f
>     >>>     Signed-off-by: Garrison Bellack <gbellack at google.com <mailto:gbellack at google.com> <mailto:gbellack at google.com <mailto:gbellack at google.com>>>
>     >>>     ---
>     >>>      cgroup.c | 9 +++++++++
>     >>>      1 file changed, 9 insertions(+)
>     >>>
>     >>>     diff --git a/cgroup.c b/cgroup.c
>     >>>     index 7ac2dd8..f8dbbde 100644
>     >>>     --- a/cgroup.c
>     >>>     +++ b/cgroup.c
>     >>>     @@ -288,6 +288,7 @@ static int read_cgroup_prop(struct cgroup_prop *property, const char *fpath)
>     >>>      {
>     >>>             char pbuf[PATH_MAX], buf[100];
>     >>>             FILE *f;
>     >>>     +       char *endptr;
>     >>>
>     >>>             if (snprintf(pbuf, PATH_MAX, "%s/%s", fpath, property->name) >= PATH_MAX) {
>     >>>                     pr_err("snprintf output was truncated");
>     >>>     @@ -315,6 +316,14 @@ static int read_cgroup_prop(struct cgroup_prop *property, const char *fpath)
>     >>>                     return -1;
>     >>>             }
>     >>>
>     >>>     +       if (strtoll(buf, &endptr, 10) == LLONG_MAX)
>     >>>     +               strcpy(buf, "-1");
>     >>>     +
>     >>>     +       if (strcmp(endptr, "\n")) {
>     >>>     +               pr_perror("Failed parsing %s, with strtoll\n", buf);
>     >>>     +               return -1;
>     >>>     +       }
>     >>>     +
>     >>>             property->value = xstrdup(buf);
>     >>>             if (!property->value)
>     >>>                     return -1;
>     >>>     --
>     >>>     2.1.0.rc2.206.gedb03e5
>     >>>
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>     >>>
>     >>>
>     >>
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>     > .
>     >
> 
>