Re: [libvirt] [PATCH] Added timestamps to storage volumes

On 07/13/2012 08:38 AM, Hendrik Schwartke wrote: > !!! DON'T PUSH until stat-time lgpl 3 issue is fixed > !!! To tests this change lgpl version to 3 in bootstrap.conf:176 > > The access, birth, modification and change times are added to > storage volumes and corresponding xml representations. > --- > bootstrap.conf | 1 + > docs/formatstorage.html.in | 13 +++++++++++++ > docs/schemas/storagevol.rng | 36 ++++++++++++++++++++++++++++++++++++ > src/conf/storage_conf.c | 18 ++++++++++++++++++ > src/conf/storage_conf.h | 13 +++++++++++++ > src/storage/storage_backend.c | 6 ++++++ > 6 files changed, 87 insertions(+) > > diff --git a/bootstrap.conf b/bootstrap.conf > index 9b42cbf..da0b960 100644 > --- a/bootstrap.conf > +++ b/bootstrap.conf > @@ -115,6 +115,7 @@ vc-list-files > vsnprintf > waitpid > warnings > +stat-time > ' Insert in sorted order. > @@ -172,6 +177,14 @@ > contains the MAC (eg SELinux) label string. > <span class="since">Since 0.4.1</span> > </dd> > +<dt><code>timestamps</code></dt> > +<dd>Provides timing information about the volume. The four sub elements since btime is omitted on Linux, maybe this would read better as 'Up to four sub-elements are present, where' > +<code>atime</code>,<code>btime</code>,<code>ctime</code> and<code>mtime</code> > + hold the access, birth, change and modification time of the volume, where known. > + The used time format is&lt;seconds&gt;.&lt;nanoseconds&gt; since the beginning > + of the epoch. This is a readonly attribute and is ignored when creating > + a volume.<span class="since">Since 0.10.0</span> > +<define name='timestamps'> > +<optional> > +<element name='timestamps'> > +<optional> > +<element name='atime'> > +<data type="string"> > +<param name="pattern">[0-9]+\.[0-9]+</param> > +</data> It might be worth writing the regex to permit eliding the sub-second resolution, on file systems that only have 1 second resolution. Given

that we are repeating this<data> four times, it might be worth defining it, for a shorter diff: <element name='atime'> <ref name='timestamp'/> </element> ... <define name='timestamp'> <data type='string'> <param name='pattern'>[0-9]+(\.[0-9]+)?</param> </data> </define> > +++ b/src/conf/storage_conf.c > @@ -1277,6 +1277,24 @@ virStorageVolTargetDefFormat(virStorageVolOptionsPtr options, > > virBufferAddLit(buf,"</permissions>\n"); > > + virBufferAddLit(buf, "<timestamps>\n"); > + virBufferAsprintf(buf, "<atime>%llu.%ld</atime>\n", > + (unsigned long long) def->timestamps.atime.tv_sec, > + def->timestamps.atime.tv_nsec); Eliding a sub-second suffix when tv_nsec == 0 would be easier with a helper function: void virStorageVolTimestampFormat(virBufferPtr buf, const char *name, struct timespec *ts) { if (ts->tv_nsec< 0)

return; virBufferAsprintf(buf, "<%s>%llu", name, (unsigned long long) ts->tv_sec); if (ts->tv_nsec) virBufferAsprintf(buf, ".%ld", tv->tv_nsec); virBufferAsprintf(buf, "</%s>\n", name); } called as: virStorageVolTimestampFormat(buf, "atime",&def->timestamps.atime); virStorageVolTimestampFormat(buf, "atime",&def->timestamps.btime); and so on. Actually, I'd list atime, mtime, ctime, btime - in that order - rather than trying to sort the names alphabetically (that is, match typical 'struct stat' ordering).

> +typedef virStorageTimestamps *virStorageTimestampsPtr; > +struct _virStorageTimestamps { > + struct timespec atime; > + /* if btime.tv_sec == -1&& btime.tv_nsec == -1 than > + * birth time is unknown Doesn't gnulib guarantee that tv_nsec == -1 in isolation is sufficient to point out an unknown value? That is, checking tv_sec == -1 is overhead.

Looking nicer. I'll have to ping upstream on gnulib about the last holdout on the relicensing of stat-time; and I'm also still waiting for the security fix in updated automake to hit Fedora.