[Libguestfs] [PATCH nbdkit 5/8] partition: Implement mapping of extents.

[Richard W.M. Jones]

---
 filters/partition/partition.c | 36 +++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/filters/partition/partition.c b/filters/partition/partition.c
index c1fe7a1..ace9f4b 100644
--- a/filters/partition/partition.c
+++ b/filters/partition/partition.c
@@ -38,6 +38,7 @@
 #include <stdint.h>
 #include <string.h>
 #include <inttypes.h>
+#include <assert.h>
 
 #include <nbdkit-filter.h>
 
@@ -222,6 +223,40 @@ partition_zero (struct nbdkit_next_ops *next_ops, void *nxdata,
   return next_ops->zero (nxdata, count, offs + h->offset, flags, err);
 }
 
+/* Extents. */
+static int
+partition_extents (struct nbdkit_next_ops *next_ops, void *nxdata,
+                   void *handle, uint32_t count, uint64_t offs, uint32_t flags,
+                   struct nbdkit_extents *extents, int *err)
+{
+  struct handle *h = handle;
+  size_t i;
+  struct nbdkit_extents *extents2;
+  struct nbdkit_extent e;
+
+  extents2 = nbdkit_extents_new (offs + h->offset);
+  if (extents2 == NULL) {
+    *err = errno;
+    return -1;
+  }
+  if (next_ops->extents (nxdata, count, offs + h->offset,
+                         flags, extents2, err) == -1)
+    goto error;
+
+  for (i = 0; i < nbdkit_extents_size (extents2); ++i) {
+    e = nbdkit_get_extent (extents2, i);
+    e.offset -= h->offset;
+    if (nbdkit_add_extent (extents, e.offset, e.length, e.type) == -1)
+      goto error;
+  }
+  nbdkit_extents_free (extents2);
+  return 0;
+
+ error:
+  nbdkit_extents_free (extents2);
+  return -1;
+}
+
 static struct nbdkit_filter filter = {
   .name              = "partition",
   .longname          = "nbdkit partition filter",
@@ -237,6 +272,7 @@ static struct nbdkit_filter filter = {
   .pwrite            = partition_pwrite,
   .trim              = partition_trim,
   .zero              = partition_zero,
+  .extents           = partition_extents,
 };
 
 NBDKIT_REGISTER_FILTER(filter)
-- 
2.20.1