11:35 a.m.
These plugins are both based on the same sparse array structure which
supports a simple implementation of extents.
---
common/sparse/sparse.h | 7 ++++++-
common/sparse/sparse.c | 29 ++++++++++++++++++++++++++++-
plugins/data/data.c | 16 +++++++++++++++-
plugins/memory/memory.c | 16 +++++++++++++++-
4 files changed, 64 insertions(+), 4 deletions(-)
diff --git a/common/sparse/sparse.h b/common/sparse/sparse.h
index 818d804..23e31b9 100644
--- a/common/sparse/sparse.h
+++ b/common/sparse/sparse.h
@@ -1,5 +1,5 @@
/* nbdkit
- * Copyright (C) 2017-2018 Red Hat Inc.
+ * Copyright (C) 2017-2019 Red Hat Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -87,4 +87,9 @@ extern void sparse_array_zero (struct sparse_array *sa,
uint32_t count, uint64_t offset)
__attribute__((__nonnull__ (1)));
+/* Return information about allocated pages and holes. */
+extern int sparse_array_extents (struct sparse_array *sa,
+ uint32_t count, uint64_t offset,
+ struct nbdkit_extents_map *extents_map);
+
#endif /* NBDKIT_SPARSE_H */
diff --git a/common/sparse/sparse.c b/common/sparse/sparse.c
index a5ace48..56bfa77 100644
--- a/common/sparse/sparse.c
+++ b/common/sparse/sparse.c
@@ -1,5 +1,5 @@
/* nbdkit
- * Copyright (C) 2017-2018 Red Hat Inc.
+ * Copyright (C) 2017-2019 Red Hat Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -360,3 +360,30 @@ sparse_array_zero (struct sparse_array *sa, uint32_t count, uint64_t
offset)
offset += n;
}
}
+
+int
+sparse_array_extents (struct sparse_array *sa,
+ uint32_t count, uint64_t offset,
+ struct nbdkit_extents_map *extents_map)
+{
+ uint32_t n, type;
+ void *p;
+
+ while (count > 0) {
+ p = lookup (sa, offset, false, &n, NULL);
+ if (n > count)
+ n = count;
+
+ if (p == NULL)
+ type = NBDKIT_EXTENT_HOLE | NBDKIT_EXTENT_ZERO;
+ else
+ type = 0; /* allocated data */
+ if (nbdkit_extent_add (extents_map, offset, n, type) == -1)
+ return -1;
+
+ count -= n;
+ offset += n;
+ }
+
+ return 0;
+}
diff --git a/plugins/data/data.c b/plugins/data/data.c
index f9d3881..d580805 100644
--- a/plugins/data/data.c
+++ b/plugins/data/data.c
@@ -1,5 +1,5 @@
/* nbdkit
- * Copyright (C) 2018 Red Hat Inc.
+ * Copyright (C) 2018-2019 Red Hat Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -378,6 +378,19 @@ data_trim (void *handle, uint32_t count, uint64_t offset)
return 0;
}
+/* Extents. */
+static int
+data_extents (void *handle, uint32_t count, uint64_t offset,
+ uint32_t flags, struct nbdkit_extents_map *extents_map)
+{
+ int r;
+
+ pthread_mutex_lock (&lock);
+ r = sparse_array_extents (sa, count, offset, extents_map);
+ pthread_mutex_unlock (&lock);
+ return r;
+}
+
static struct nbdkit_plugin plugin = {
.name = "data",
.version = PACKAGE_VERSION,
@@ -394,6 +407,7 @@ static struct nbdkit_plugin plugin = {
.pwrite = data_pwrite,
.zero = data_zero,
.trim = data_trim,
+ .extents = data_extents,
/* In this plugin, errno is preserved properly along error return
* paths from failed system calls.
*/
diff --git a/plugins/memory/memory.c b/plugins/memory/memory.c
index e27e127..fa09a35 100644
--- a/plugins/memory/memory.c
+++ b/plugins/memory/memory.c
@@ -1,5 +1,5 @@
/* nbdkit
- * Copyright (C) 2017-2018 Red Hat Inc.
+ * Copyright (C) 2017-2019 Red Hat Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -170,6 +170,19 @@ memory_trim (void *handle, uint32_t count, uint64_t offset)
return 0;
}
+/* Extents. */
+static int
+memory_extents (void *handle, uint32_t count, uint64_t offset,
+ uint32_t flags, struct nbdkit_extents_map *extents_map)
+{
+ int r;
+
+ pthread_mutex_lock (&lock);
+ r = sparse_array_extents (sa, count, offset, extents_map);
+ pthread_mutex_unlock (&lock);
+ return r;
+}
+
static struct nbdkit_plugin plugin = {
.name = "memory",
.version = PACKAGE_VERSION,
@@ -185,6 +198,7 @@ static struct nbdkit_plugin plugin = {
.pwrite = memory_pwrite,
.zero = memory_zero,
.trim = memory_trim,
+ .extents = memory_extents,
/* In this plugin, errno is preserved properly along error return
* paths from failed system calls.
*/
--
2.20.1