Re: [Libguestfs] [nbdkit PATCH] Update filters to support FUA flags.

From: "Richard W.M. Jones" <rjones(a)redhat.com&gt;

This patch may be worth squashing? --- docs/nbdkit-filter.pod | 65 +++++++++++++++++++++++++++++++++++++++++++------ include/nbdkit-filter.h | 29 ++++++++++++---------- src/filters.c | 55 ++++++++++++++++++++--------------------- 3 files changed, 101 insertions(+), 48 deletions(-)

@@ -333,11 +342,21 @@ message B<and> set C<errno>, then return C<-1>. int (*pwrite) (struct nbdkit_next_ops *next_ops, void *nxdata, void *handle, - const void *buf, uint32_t count, uint64_t offset); + const void *buf, uint32_t count, uint64_t offset, + uint32_t flags); This intercepts the plugin C<.pwrite> method and can be used to modify data written by the plugin. +At this time, flags may include C<NBDKIT_FLAG_FUA> on input based on +the result of C<.can_flush>. In turn, the filter may only pass +C<NBDKIT_FLAG_FUA> on to C<next_ops->pwrite> if C<next_ops->can_flush> +returned true. + +This function will not be called if C<.can_write> returned false; in +turn, the filter should not call C<next_ops->pwrite> if C<next_ops->can_write> +did not return true.