search for: flag_may_trim

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...

...0:05:15PM +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 av...

These are accessible from the plugin by: import nbdkit if flags & nbdkit.FLAG_MAY_TRIM: &c. 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(+)...

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. > >...

And fill out most of the missing bits of the API. Rich.

...t:offset+count] -def pwrite(h, buf, offset): +def pwrite(h, buf, offset, flags): global disk end = offset + len(buf) disk[offset:end] = buf -def zero(h, count, offset, may_trim): +def zero(h, count, offset, flags): global disk - if may_trim: + if flags & nbdkit.FLAG_MAY_TRIM: disk[offset:offset+count] = bytearray(count) else: nbdkit.set_error(errno.EOPNOTSUPP) diff --git a/plugins/python/nbdkit-python-plugin.pod b/plugins/python/nbdkit-python-plugin.pod index 6453474..882c0d8 100644 --- a/plugins/python/nbdkit-python-plugin.pod +++ b/plugins/pyth...

...t:offset+count] -def pwrite(h, buf, offset): +def pwrite(h, buf, offset, flags): global disk end = offset + len(buf) disk[offset:end] = buf -def zero(h, count, offset, may_trim): +def zero(h, count, offset, flags): global disk - if may_trim: + if flags & nbdkit.FLAG_MAY_TRIM: disk[offset:offset+count] = bytearray(count) else: nbdkit.set_error(errno.EOPNOTSUPP) diff --git a/plugins/python/nbdkit-python-plugin.pod b/plugins/python/nbdkit-python-plugin.pod index e089bc9..f393e8f 100644 --- a/plugins/python/nbdkit-python-plugin.pod +++ b/plugins/pyth...

v3 was here: https://www.redhat.com/archives/libguestfs/2019-November/msg00209.html In v4: - Rebase on top of current master. Includes various fixes and updates required because of Nir's patches that went into master. - Fix api_version() -> API_VERSION in patch 2 noted previously on the mailing list. Rich.

v2 was here: https://www.redhat.com/archives/libguestfs/2019-November/msg00163.html I pushed patch 1 (with spelling fix), patch 4 and patch 5 since those were previously ACKed on the list. Differences in v3: - Add error checking to PyModule_AddIntConstant. - Use API_VERSION constant instead of function. - Add max API version supported to --dump-plugin output. - Print API_VERSION selected by

v1: https://www.redhat.com/archives/libguestfs/2019-November/msg00153.html v2: - Fix implementation of can_cache. - Add implementation of can_fua. - Add a very thorough test suite which tests every command + flag combination.

...it a/plugins/python/nbdkit-python-plugin.pod b/plugins/python/nbdkit-python-plugin.pod index 0fd4dcb..ee58cd7 100644 --- a/plugins/python/nbdkit-python-plugin.pod +++ b/plugins/python/nbdkit-python-plugin.pod @@ -293,6 +293,19 @@ because there is nothing to optimize if S<C<flags & nbdkit.FLAG_MAY_TRIM>> is false), use S<C<nbdkit.set_error (errno.EOPNOTSUPP)>>. +=item C<cache> + +(Optional) + + def cache(h, count, offset, flags): + # no return value + +The body of your C<cache> function should prefetch data in the +indicated range. + +If the cache operation fail...

...13 @@ contents will be garbage collected. def can_trim(h): # return a boolean +=item C<can_cache> + +(Optional) + + def can_cache(h): + # return a boolean + =item C<pread> (Required) @@ -293,6 +300,19 @@ because there is nothing to optimize if S<C<flags & nbdkit.FLAG_MAY_TRIM>> is false), use S<C<nbdkit.set_error (errno.EOPNOTSUPP)>>. +=item C<cache> + +(Optional) + + def cache(h, count, offset, flags): + # no return value + +The body of your C<cache> function should prefetch data in the +indicated range. + +If the cache operation fail...

...ero(h, count, offset, flags): + expect_fua = cfg.get ('zero_expect_fua', False) + actual_fua = bool (flags & nbdkit.FLAG_FUA) + assert expect_fua == actual_fua + expect_may_trim = cfg.get ('zero_expect_may_trim', False) + actual_may_trim = bool (flags & nbdkit.FLAG_MAY_TRIM) + assert expect_may_trim == actual_may_trim + expect_fast_zero = cfg.get ('zero_expect_fast_zero', False) + actual_fast_zero = bool (flags & nbdkit.FLAG_FAST_ZERO) + assert expect_fast_zero == actual_fast_zero + h['disk'][offset:offset+count] = bytearray(count) +...

...gs): > + expect_fua = cfg.get ('zero_expect_fua', False) > + actual_fua = bool (flags & nbdkit.FLAG_FUA) > + assert expect_fua == actual_fua > + expect_may_trim = cfg.get ('zero_expect_may_trim', False) > + actual_may_trim = bool (flags & nbdkit.FLAG_MAY_TRIM) > + assert expect_may_trim == actual_may_trim > + expect_fast_zero = cfg.get ('zero_expect_fast_zero', False) > + actual_fast_zero = bool (flags & nbdkit.FLAG_FAST_ZERO) > + assert expect_fast_zero == actual_fast_zero > + h['disk'][offset:offset+co...

...ion may be optimized as a trim as long > -as subsequent reads see zeroes. > +The body of your C<zero> function should ensure that C<count> bytes of > +the disk, starting at C<offset>, will read back as zero. C<flags> is > +a bitmask which may include C<nbdkit.FLAG_MAY_TRIM>, > +C<nbdkit.FLAG_FUA>, C<nbdkit.FLAG_FAST_ZERO>. Well, technically FAST_ZERO can't be set until later in the series when you plumb in the can_fast_zero callback... :) > static int > -py_pwrite (void *handle, const void *buf, > - uint32_t count, uint6...