On Fri, Nov 22, 2019 at 11:26:55PM +0200, Nir Soffer wrote:
On Fri, Nov 22, 2019 at 10:52 PM Richard W.M. Jones <rjones@redhat.com> wrote:
On Fri, Nov 22, 2019 at 10:05:15PM +0200, Nir Soffer wrote:
On Fri, Nov 22, 2019 at 9:54 PM Richard W.M. Jones <rjones@redhat.com> wrote:
These are accessible from the plugin by:
import nbdkit
if flags & nbdkit.FLAG_MAY_TRIM: &c.
Nice way to expose the flags!
Many (all?) of these are not yet useful for plugins, some will never be useful, but they only consume a tiny bit of memory and it's nice to have the complete set available for future use. --- plugins/python/python.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+)
diff --git a/plugins/python/python.c b/plugins/python/python.c index d65ac45..69cf4e9 100644 --- a/plugins/python/python.c +++ b/plugins/python/python.c @@ -231,6 +231,33 @@ create_nbdkit_module (void) nbdkit_error ("could not create the nbdkit API module"); exit (EXIT_FAILURE); } + + /* Constants corresponding to various flags. */ + PyModule_AddIntConstant (m, "THREAD_MODEL_SERIALIZE_CONNECTIONS", + NBDKIT_THREAD_MODEL_SERIALIZE_CONNECTIONS);
This can fail and needs cleanup. Very unlikely and a lot of code in the standard library have this issue.
In sanlock we do:
if (PyModule_AddIntConstant(m, "LSFLAG_ADD", SANLK_LSF_ADD)) return -1;
And the caller decref the module object and return NULL.
See https://github.com/nirs/sanlock/blob/53f7f0284c084ac2e4542fd1f71d0406075adb5... https://github.com/nirs/sanlock/blob/53f7f0284c084ac2e4542fd1f71d0406075adb5...
Yes I can make this change. It's worth it in case there is some subtle Python API change in future that we need to be aware of.
We can in fact exit if load() fails so I guess we don't need to bother doing the PY_DECREF for this case.
exit can hide the original error if we are not careful, so it is best avoided.
It is nice to decref and return NULL, the user code will fail with nice traceback about (likely) MemoryError.
And it does not cost much to do the right thing.
This is called before we enter any Python code so I don't think that will work. (In general Python is embedded in C in nbdkit, so everything works in reverse to usual Python/C extensions.) Rich.
Thanks,
Rich.
+ PyModule_AddIntConstant (m, "THREAD_MODEL_SERIALIZE_ALL_REQUESTS", + NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS); + PyModule_AddIntConstant (m, "THREAD_MODEL_SERIALIZE_REQUESTS", + NBDKIT_THREAD_MODEL_SERIALIZE_REQUESTS); + PyModule_AddIntConstant (m, "THREAD_MODEL_PARALLEL", + NBDKIT_THREAD_MODEL_PARALLEL); + + PyModule_AddIntConstant (m, "FLAG_MAY_TRIM", NBDKIT_FLAG_MAY_TRIM); + PyModule_AddIntConstant (m, "FLAG_FUA", NBDKIT_FLAG_FUA); + PyModule_AddIntConstant (m, "FLAG_REQ_ONE", NBDKIT_FLAG_REQ_ONE); + PyModule_AddIntConstant (m, "FLAG_FAST_ZERO", NBDKIT_FLAG_FAST_ZERO); + + PyModule_AddIntConstant (m, "FUA_NONE", NBDKIT_FUA_NONE); + PyModule_AddIntConstant (m, "FUA_EMULATE", NBDKIT_FUA_EMULATE); + PyModule_AddIntConstant (m, "FUA_NATIVE", NBDKIT_FUA_NATIVE); + + PyModule_AddIntConstant (m, "CACHE_NONE", NBDKIT_CACHE_NONE); + PyModule_AddIntConstant (m, "CACHE_EMULATE", NBDKIT_CACHE_EMULATE); + PyModule_AddIntConstant (m, "CACHE_NATIVE", NBDKIT_CACHE_NATIVE); + + PyModule_AddIntConstant (m, "EXTENT_HOLE", NBDKIT_EXTENT_HOLE); + PyModule_AddIntConstant (m, "EXTENT_ZERO", NBDKIT_EXTENT_ZERO); + return m; }
-- 2.23.0
-- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-p2v converts physical machines to virtual machines. Boot with a live CD or over the network (PXE) and turn machines into KVM guests. http://libguestfs.org/virt-v2v
-- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/