Re: [Libguestfs] [nbdkit PATCH 04/10] plugins: Wire up in-memory plugin support for NBD_INFO_INIT_STATE
On Mon, Feb 10, 2020 at 03:43:57PM -0600, Eric Blake wrote:
+/* Does current client start with a sparse image. */
+static int
+memory_init_sparse (void *handle)
+{
+ ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&lock);
+ return sparse_array_is_sparse (sa);
+}
+
+/* Does current client start with all zeroes. */
+static int
+memory_init_zero (void *handle)
+{
+ ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&lock);
+ return sparse_array_is_zero (sa);
+}
I was going to say these are always true, but then I remembered that
NBD_INIT_* records the state at the start of the *connection*, not the
start of the *server* instance, and if there's been a previous
connection then the RAM disk might indeed contain non-zero non-sparse
data.
Do we need to define what NBD_INIT_ZERO means when disk size = 0 ?
By the way, the data plugin can also be updated since it also uses the
sparse array feature.
Rich.
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