- Add FAIL macro to simplfy error handling. This can proabably be used by other examples. - Support simple sparsification using full requests. Nir Soffer (2): examples: copy-libev: Add FAIL macro examples: copy-libev.c: Simple sparsifying examples/Makefile.am | 1 + examples/copy-libev.c | 147 +++++++++++++++++++++++++----------------- 2 files changed, 89 insertions(+), 59 deletions(-) --=20 2.26.2
Nir Soffer
2021-Mar-05 17:16 UTC
[Libguestfs] [PATCH libnbd 1/2] examples: copy-libev: Add FAIL macro
Stop repeating fprintf(stderr, "..."); exit(EXIT_FAILURE).
Signed-off-by: Nir Soffer <nsoffer at redhat.com>
---
examples/copy-libev.c | 79 +++++++++++++++++++------------------------
1 file changed, 34 insertions(+), 45 deletions(-)
diff --git a/examples/copy-libev.c b/examples/copy-libev.c
index 034711a..70a9811 100644
--- a/examples/copy-libev.c
+++ b/examples/copy-libev.c
@@ -17,8 +17,10 @@
*/
#include <assert.h>
+#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
+#include <string.h>
#include <unistd.h>
#include <libnbd.h>
@@ -42,10 +44,18 @@
#define MIN(a,b) (a) < (b) ? (a) : (b)
-#define DEBUG(fmt, ...) \
- do { \
- if (debug) \
- fprintf (stderr, "copy-libev: " fmt "\n", ##
__VA_ARGS__); \
+#define PROG "copy-libev"
+
+#define DEBUG(fmt, ...) \
+ do { \
+ if (debug) \
+ fprintf (stderr, PROG ": " fmt "\n", ## __VA_ARGS__);
\
+ } while (0)
+
+#define FAIL(fmt, ...) \
+ do { \
+ fprintf (stderr, PROG ": " fmt "\n", ## __VA_ARGS__);
\
+ exit (EXIT_FAILURE); \
} while (0)
struct connection {
@@ -111,10 +121,8 @@ start_read(struct request *r)
(nbd_completion_callback) { .callback=read_completed,
.user_data=r },
0);
- if (cookie == -1) {
- fprintf (stderr, "start_read: %s", nbd_get_error ());
- exit (EXIT_FAILURE);
- }
+ if (cookie == -1)
+ FAIL ("Cannot start read: %s", nbd_get_error ());
offset += r->length;
}
@@ -133,10 +141,8 @@ read_completed (void *user_data, int *error)
(nbd_completion_callback) { .callback=write_completed,
.user_data=r },
0);
- if (cookie == -1) {
- fprintf (stderr, "read_completed: %s", nbd_get_error ());
- exit (EXIT_FAILURE);
- }
+ if (cookie == -1)
+ FAIL ("Cannot start write: %s", nbd_get_error ());
return 1;
}
@@ -207,44 +213,31 @@ main (int argc, char *argv[])
loop = EV_DEFAULT;
- if (argc != 3) {
- fprintf (stderr, "Usage: copy-ev src-uri dst-uri\n");
- exit (EXIT_FAILURE);
- }
+ if (argc != 3)
+ FAIL ("Usage: %s src-uri dst-uri", PROG);
src.nbd = nbd_create ();
- if (src.nbd == NULL) {
- fprintf (stderr, "nbd_create: %s\n", nbd_get_error ());
- exit (EXIT_FAILURE);
- }
-
+ if (src.nbd == NULL)
+ FAIL ("Cannot create source: %s", nbd_get_error ());
dst.nbd = nbd_create ();
- if (dst.nbd == NULL) {
- fprintf (stderr, "nbd_create: %s\n", nbd_get_error ());
- exit (EXIT_FAILURE);
- }
+ if (dst.nbd == NULL)
+ FAIL ("Cannot create destination: %s", nbd_get_error ());
debug = nbd_get_debug (src.nbd);
/* Connecting is fast, so use the syncronous API. */
- if (nbd_connect_uri (src.nbd, argv[1])) {
- fprintf (stderr, "nbd_connect_uri: %s\n", nbd_get_error ());
- exit (EXIT_FAILURE);
- }
+ if (nbd_connect_uri (src.nbd, argv[1]))
+ FAIL ("Cannot connect to source: %s", nbd_get_error ());
- if (nbd_connect_uri (dst.nbd, argv[2])) {
- fprintf (stderr, "nbd_connect_uri: %s\n", nbd_get_error ());
- exit (EXIT_FAILURE);
- }
+ if (nbd_connect_uri (dst.nbd, argv[2]))
+ FAIL ("Cannot connect to destination: %s", nbd_get_error ());
size = nbd_get_size (src.nbd);
- if (size > nbd_get_size (dst.nbd)) {
- fprintf (stderr, "destinatio is not large enough\n");
- exit (EXIT_FAILURE);
- }
+ if (size > nbd_get_size (dst.nbd))
+ FAIL ("Destinatio is not large enough\n");
/* Start the copy "loop". When request completes, it starts the
* next request, until entire image was copied. */
@@ -253,10 +246,8 @@ main (int argc, char *argv[])
struct request *r = &requests[i];
r->data = malloc (REQUEST_SIZE);
- if (r->data == NULL) {
- perror ("malloc");
- exit (EXIT_FAILURE);
- }
+ if (r->data == NULL)
+ FAIL ("Cannot allocate buffer: %s", strerror (errno));
start_read(r);
}
@@ -285,10 +276,8 @@ main (int argc, char *argv[])
/* Copy completed - flush data to storage. */
DEBUG("flush");
- if (nbd_flush (dst.nbd, 0)) {
- fprintf (stderr, "Cannot flush: %s", nbd_get_error ());
- exit (EXIT_FAILURE);
- }
+ if (nbd_flush (dst.nbd, 0))
+ FAIL ("Cannot flush: %s", nbd_get_error ());
/* We don't care about errors here since data was flushed. */
--
2.26.2
Nir Soffer
2021-Mar-05 17:16 UTC
[Libguestfs] [PATCH libnbd 2/2] examples: copy-libev.c: Simple sparsifying
If a request includes only zeroes, use efficient zero method instead of
sending the zeroes over the wire.
Signed-off-by: Nir Soffer <nsoffer at redhat.com>
---
examples/Makefile.am | 1 +
examples/copy-libev.c | 68 ++++++++++++++++++++++++++++++++++---------
2 files changed, 55 insertions(+), 14 deletions(-)
diff --git a/examples/Makefile.am b/examples/Makefile.am
index a8286a3..27d2ead 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -224,6 +224,7 @@ copy_libev_SOURCES = \
copy-libev.c \
$(NULL)
copy_libev_CPPFLAGS = \
+ -I$(top_srcdir)/common/include \
-I$(top_srcdir)/include \
$(NULL)
copy_libev_CFLAGS = \
diff --git a/examples/copy-libev.c b/examples/copy-libev.c
index 70a9811..d9fb2c7 100644
--- a/examples/copy-libev.c
+++ b/examples/copy-libev.c
@@ -27,6 +27,8 @@
#include <ev.h>
+#include "iszero.h"
+
/* These values depend on the enviroment tested.
*
* For shared storage using direct I/O:
@@ -79,9 +81,12 @@ static int64_t offset;
static int64_t written;
static bool debug;
+static void start_request(struct request *r);
static void start_read(struct request *r);
+static void start_write(struct request *r);
+static void start_zero(struct request *r);
static int read_completed(void *user_data, int *error);
-static int write_completed(void *user_data, int *error);
+static int request_completed(void *user_data, int *error);
static inline int
get_fd(struct connection *c)
@@ -104,16 +109,25 @@ get_events(struct connection *c)
return events;
}
+/* Start async copy or zero request. */
static void
-start_read(struct request *r)
+start_request(struct request *r)
{
- int64_t cookie;
-
assert (offset < size);
r->length = MIN (REQUEST_SIZE, size - offset);
r->offset = offset;
+ start_read (r);
+
+ offset += r->length;
+}
+
+static void
+start_read(struct request *r)
+{
+ int64_t cookie;
+
DEBUG ("start read offset=%ld len=%ld", r->offset,
r->length);
cookie = nbd_aio_pread (
@@ -123,38 +137,64 @@ start_read(struct request *r)
0);
if (cookie == -1)
FAIL ("Cannot start read: %s", nbd_get_error ());
-
- offset += r->length;
}
static int
read_completed (void *user_data, int *error)
{
struct request *r = (struct request *)user_data;
+
+ DEBUG ("read completed offset=%ld len=%ld", r->offset,
r->length);
+
+ if (is_zero (r->data, r->length))
+ start_zero (r);
+ else
+ start_write (r);
+
+ return 1;
+}
+
+static void
+start_write(struct request *r)
+{
int64_t cookie;
- DEBUG ("read completed, starting write offset=%ld len=%ld",
- r->offset, r->length);
+ DEBUG ("start write offset=%ld len=%ld", r->offset,
r->length);
cookie = nbd_aio_pwrite (
dst.nbd, r->data, r->length, r->offset,
- (nbd_completion_callback) { .callback=write_completed,
+ (nbd_completion_callback) { .callback=request_completed,
.user_data=r },
0);
if (cookie == -1)
FAIL ("Cannot start write: %s", nbd_get_error ());
+}
- return 1;
+static void
+start_zero(struct request *r)
+{
+ int64_t cookie;
+
+ DEBUG ("start zero offset=%ld len=%ld", r->offset,
r->length);
+
+ cookie = nbd_aio_zero (
+ dst.nbd, r->length, r->offset,
+ (nbd_completion_callback) { .callback=request_completed,
+ .user_data=r },
+ 0);
+ if (cookie == -1)
+ FAIL ("Cannot start zero: %s", nbd_get_error ());
}
+/* Called when async copy or zero request completed. */
static int
-write_completed (void *user_data, int *error)
+request_completed (void *user_data, int *error)
{
struct request *r = (struct request *)user_data;
written += r->length;
- DEBUG ("write completed offset=%ld len=%ld", r->offset,
r->length);
+ DEBUG ("request completed offset=%ld len=%ld", r->offset,
r->length);
if (written == size) {
/* The last write completed. Stop all watchers and break out
@@ -168,7 +208,7 @@ write_completed (void *user_data, int *error)
/* If we have data to read, start a new read. */
if (offset < size)
- start_read(r);
+ start_request(r);
return 1;
}
@@ -249,7 +289,7 @@ main (int argc, char *argv[])
if (r->data == NULL)
FAIL ("Cannot allocate buffer: %s", strerror (errno));
- start_read(r);
+ start_request(r);
}
/* Start watching events on src and dst handles. */
--
2.26.2