[Libguestfs] [nbdkit PATCH v2 19/24] offset, partition: Implement .cache
In the offset and partition filters, all we need to do is adjust cache
requests to the correct offset (well, technically, this isn't enabled
until a later patch flips the default for .can_cache to pass-through).
Signed-off-by: Eric Blake <eblake(a)redhat.com>
---
filters/offset/offset.c | 12 +++++++++++-
filters/partition/partition.c | 12 ++++++++++++
2 files changed, 23 insertions(+), 1 deletion(-)
diff --git a/filters/offset/offset.c b/filters/offset/offset.c
index 633a1c7..fe07d28 100644
--- a/filters/offset/offset.c
+++ b/filters/offset/offset.c
@@ -1,5 +1,5 @@
/* nbdkit
- * Copyright (C) 2018 Red Hat Inc.
+ * Copyright (C) 2018-2019 Red Hat Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
@@ -164,6 +164,15 @@ offset_extents (struct nbdkit_next_ops *next_ops, void *nxdata,
return 0;
}
+/* Cache data. */
+static int
+offset_cache (struct nbdkit_next_ops *next_ops, void *nxdata,
+ void *handle, uint32_t count, uint64_t offs, uint32_t flags,
+ int *err)
+{
+ return next_ops->cache (nxdata, count, offs + offset, flags, err);
+}
+
static struct nbdkit_filter filter = {
.name = "offset",
.longname = "nbdkit offset filter",
@@ -177,6 +186,7 @@ static struct nbdkit_filter filter = {
.trim = offset_trim,
.zero = offset_zero,
.extents = offset_extents,
+ .cache = offset_cache,
};
NBDKIT_REGISTER_FILTER(filter)
diff --git a/filters/partition/partition.c b/filters/partition/partition.c
index a635df8..ee2cc77 100644
--- a/filters/partition/partition.c
+++ b/filters/partition/partition.c
@@ -254,6 +254,17 @@ partition_extents (struct nbdkit_next_ops *next_ops, void *nxdata,
return 0;
}
+/* Cache data. */
+static int
+partition_cache (struct nbdkit_next_ops *next_ops, void *nxdata,
+ void *handle, uint32_t count, uint64_t offs, uint32_t flags,
+ int *err)
+{
+ struct handle *h = handle;
+
+ return next_ops->cache (nxdata, count, offs + h->offset, flags, err);
+}
+
static struct nbdkit_filter filter = {
.name = "partition",
.longname = "nbdkit partition filter",
@@ -270,6 +281,7 @@ static struct nbdkit_filter filter = {
.trim = partition_trim,
.zero = partition_zero,
.extents = partition_extents,
+ .cache = partition_cache,
};
NBDKIT_REGISTER_FILTER(filter)
--
2.20.1