* [Qemu-devel] [patch 0/5] NBD support improvement
@ 2008-06-27 11:02 Laurent.Vivier
2008-06-27 11:02 ` [Qemu-devel] [patch 1/5] qemu-nbd: cleanup Laurent.Vivier
` (4 more replies)
0 siblings, 5 replies; 10+ messages in thread
From: Laurent.Vivier @ 2008-06-27 11:02 UTC (permalink / raw)
To: qemu-devel; +Cc: Laurent.Vivier
This series of patches improves NBD support in QEMU.
[PATCH 1/5] qemu-nbd: cleanup
[PATCH 2/5] qemu-nbd: merge NBD client/server
[PATCH 3/5] qemu-nbd: add a parameter to disable host cache.
[PATCH 4/5] qemu-nbd: allow to share a disk image
[PATCH 5/5] Allow QEMU to connect directly to an NBD server
Laurent
--
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Qemu-devel] [patch 1/5] qemu-nbd: cleanup
2008-06-27 11:02 [Qemu-devel] [patch 0/5] NBD support improvement Laurent.Vivier
@ 2008-06-27 11:02 ` Laurent.Vivier
2008-06-27 11:02 ` [Qemu-devel] [patch 2/5] qemu-nbd: merge NBD client/server Laurent.Vivier
` (3 subsequent siblings)
4 siblings, 0 replies; 10+ messages in thread
From: Laurent.Vivier @ 2008-06-27 11:02 UTC (permalink / raw)
To: qemu-devel; +Cc: Laurent.Vivier
[-- Attachment #1: nbd-cleanup.patch --]
[-- Type: text/plain, Size: 2254 bytes --]
This patch removes "#include <malloc.h>" and correct a printf format.
(from Carlo Marcelo Arenas Belon <carenas@sajinet.com.pe>).
Fill the last element of lopt (for getopt_long()) to mark the end of parameters
list. Add an entry in qemu-doc.texi.
---
nbd.c | 4 ++--
qemu-doc.texi | 6 ++++++
qemu-nbd.c | 2 +-
3 files changed, 9 insertions(+), 3 deletions(-)
Index: qemu/nbd.c
===================================================================
--- qemu.orig/nbd.c 2008-06-27 11:34:18.000000000 +0200
+++ qemu/nbd.c 2008-06-27 11:34:28.000000000 +0200
@@ -388,8 +388,8 @@ int nbd_trip(BlockDriverState *bs, int c
}
if (len > sizeof(data)) {
- LOG("len (%u) is larger than max len (%u)",
- len, sizeof(data));
+ LOG("len (%u) is larger than max len (%lu)",
+ len, (unsigned long)sizeof(data));
errno = EINVAL;
return -1;
}
Index: qemu/qemu-nbd.c
===================================================================
--- qemu.orig/qemu-nbd.c 2008-06-27 11:34:18.000000000 +0200
+++ qemu/qemu-nbd.c 2008-06-27 11:34:28.000000000 +0200
@@ -21,7 +21,6 @@
#include "block_int.h"
#include "nbd.h"
-#include <malloc.h>
#include <stdarg.h>
#include <stdio.h>
#include <getopt.h>
@@ -168,6 +167,7 @@ int main(int argc, char **argv)
{ "partition", 1, 0, 'P' },
{ "snapshot", 0, 0, 's' },
{ "verbose", 0, 0, 'v' },
+ { NULL, 0, 0, 0 }
};
int ch;
int opt_ind = 0;
Index: qemu/qemu-doc.texi
===================================================================
--- qemu.orig/qemu-doc.texi 2008-06-27 11:34:18.000000000 +0200
+++ qemu/qemu-doc.texi 2008-06-27 11:34:28.000000000 +0200
@@ -1307,6 +1307,7 @@ snapshots.
* disk_images_snapshot_mode:: Snapshot mode
* vm_snapshots:: VM snapshots
* qemu_img_invocation:: qemu-img Invocation
+* qemu_nbd_invocation:: qemu-nbd Invocation
* host_drives:: Using host drives
* disk_images_fat_images:: Virtual FAT disk images
@end menu
@@ -1389,6 +1390,11 @@ state is not saved or restored properly
@include qemu-img.texi
+@node qemu_nbd_invocation
+@subsection @code{qemu-nbd} Invocation
+
+@include qemu-nbd.texi
+
@node host_drives
@subsection Using host drives
--
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Qemu-devel] [patch 2/5] qemu-nbd: merge NBD client/server
2008-06-27 11:02 [Qemu-devel] [patch 0/5] NBD support improvement Laurent.Vivier
2008-06-27 11:02 ` [Qemu-devel] [patch 1/5] qemu-nbd: cleanup Laurent.Vivier
@ 2008-06-27 11:02 ` Laurent.Vivier
2008-07-02 21:26 ` Thiemo Seufer
2008-06-27 11:02 ` [Qemu-devel] [patch 3/5] qemu-nbd: add a parameter to disable host cache Laurent.Vivier
` (2 subsequent siblings)
4 siblings, 1 reply; 10+ messages in thread
From: Laurent.Vivier @ 2008-06-27 11:02 UTC (permalink / raw)
To: qemu-devel; +Cc: Laurent.Vivier
[-- Attachment #1: qemu-nbd-local.patch --]
[-- Type: text/plain, Size: 11968 bytes --]
This patch allows to connect directly a disk image file to an NBD
device. It introduces the use of a unix socket (instead of inet).
- To connect a file to a device:
# qemu-nbd --connect=/dev/nbd0 my_disk.qcow2
Then you can see directly your disk (no need of nbd-client):
# fdisk -l /dev/nbd0
Disk /dev/nbd0: 4294 MB, 4294967296 bytes
255 heads, 63 sectors/track, 522 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/nbd0p1 * 1 492 3951958+ 83 Linux
/dev/nbd0p2 493 522 240975 5 Extended
/dev/nbd0p5 493 522 240943+ 82 Linux swap /
Solaris
- To disconnect the file from the device:
# qemu-nbd --disconnect /dev/nbd0
Changelog:
- v2: call show_parts() from client and avoid the sleep(1). Thank you to
Avi and Anthony. Include my cleanup patch and comments from Carlo
Marcelo Arenas Belon.
- v3: allow to specify unix socket name with "--socket" and update
documentation.
---
nbd.c | 74 ++++++++++++++++++++++++++++---
nbd.h | 5 +-
qemu-nbd.c | 137 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
qemu-nbd.texi | 6 ++
4 files changed, 212 insertions(+), 10 deletions(-)
Index: qemu/nbd.c
===================================================================
--- qemu.orig/nbd.c 2008-06-27 11:34:28.000000000 +0200
+++ qemu/nbd.c 2008-06-27 11:34:35.000000000 +0200
@@ -25,6 +25,7 @@
#include <ctype.h>
#include <inttypes.h>
#include <sys/socket.h>
+#include <sys/un.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
@@ -183,6 +184,65 @@ error:
return -1;
}
+int unix_socket_incoming(const char *path)
+{
+ int s;
+ struct sockaddr_un addr;
+ int serrno;
+
+ s = socket(PF_UNIX, SOCK_STREAM, 0);
+ if (s == -1) {
+ return -1;
+ }
+
+ memset(&addr, 0, sizeof(addr));
+ addr.sun_family = AF_UNIX;
+ pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
+
+ if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
+ goto error;
+ }
+
+ if (listen(s, 128) == -1) {
+ goto error;
+ }
+
+ return s;
+error:
+ serrno = errno;
+ close(s);
+ errno = serrno;
+ return -1;
+}
+
+int unix_socket_outgoing(const char *path)
+{
+ int s;
+ struct sockaddr_un addr;
+ int serrno;
+
+ s = socket(PF_UNIX, SOCK_STREAM, 0);
+ if (s == -1) {
+ return -1;
+ }
+
+ memset(&addr, 0, sizeof(addr));
+ addr.sun_family = AF_UNIX;
+ pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
+
+ if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
+ goto error;
+ }
+
+ return s;
+error:
+ serrno = errno;
+ close(s);
+ errno = serrno;
+ return -1;
+}
+
+
/* Basic flow
Server Client
@@ -225,12 +285,10 @@ int nbd_negotiate(BlockDriverState *bs,
return 0;
}
-int nbd_receive_negotiate(int fd, int csock)
+int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize)
{
char buf[8 + 8 + 8 + 128];
uint64_t magic;
- off_t size;
- size_t blocksize;
TRACE("Receiving negotation.");
@@ -241,8 +299,8 @@ int nbd_receive_negotiate(int fd, int cs
}
magic = be64_to_cpup((uint64_t*)(buf + 8));
- size = be64_to_cpup((uint64_t*)(buf + 16));
- blocksize = 1024;
+ *size = be64_to_cpup((uint64_t*)(buf + 16));
+ *blocksize = 1024;
TRACE("Magic is %c%c%c%c%c%c%c%c",
isprint(buf[0]) ? buf[0] : '.',
@@ -254,7 +312,7 @@ int nbd_receive_negotiate(int fd, int cs
isprint(buf[6]) ? buf[6] : '.',
isprint(buf[7]) ? buf[7] : '.');
TRACE("Magic is 0x%" PRIx64, magic);
- TRACE("Size is %" PRIu64, size);
+ TRACE("Size is %" PRIu64, *size);
if (memcmp(buf, "NBDMAGIC", 8) != 0) {
LOG("Invalid magic received");
@@ -269,7 +327,11 @@ int nbd_receive_negotiate(int fd, int cs
errno = EINVAL;
return -1;
}
+ return 0;
+}
+int nbd_init(int fd, int csock, off_t size, size_t blocksize)
+{
TRACE("Setting block size to %lu", (unsigned long)blocksize);
if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) == -1) {
Index: qemu/nbd.h
===================================================================
--- qemu.orig/nbd.h 2008-06-27 11:34:18.000000000 +0200
+++ qemu/nbd.h 2008-06-27 11:34:35.000000000 +0200
@@ -27,9 +27,12 @@
#include "block_int.h"
int tcp_socket_incoming(const char *address, uint16_t port);
+int unix_socket_outgoing(const char *path);
+int unix_socket_incoming(const char *path);
int nbd_negotiate(BlockDriverState *bs, int csock, off_t size);
-int nbd_receive_negotiate(int fd, int csock);
+int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize);
+int nbd_init(int fd, int csock, off_t size, size_t blocksize);
int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset, off_t *offset, bool readonly);
int nbd_client(int fd, int csock);
int nbd_disconnect(int fd);
Index: qemu/qemu-nbd.c
===================================================================
--- qemu.orig/qemu-nbd.c 2008-06-27 11:34:28.000000000 +0200
+++ qemu/qemu-nbd.c 2008-06-27 11:34:35.000000000 +0200
@@ -25,10 +25,14 @@
#include <stdio.h>
#include <getopt.h>
#include <err.h>
+#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
+#include <signal.h>
+
+#define SOCKET_PATH "/var/lock/qemu-nbd-%s"
int verbose;
@@ -41,14 +45,18 @@ static void usage(const char *name)
" -p, --port=PORT port to listen on (default `1024')\n"
" -o, --offset=OFFSET offset into the image\n"
" -b, --bind=IFACE interface to bind to (default `0.0.0.0')\n"
+" -k, --socket=PATH path to the unix socket\n"
+" (default '"SOCKET_PATH"')\n"
" -r, --read-only export read-only\n"
" -P, --partition=NUM only expose partition NUM\n"
+" -c, --connect=DEV connect FILE to the local NBD device DEV\n"
+" -d, --disconnect disconnect the specified device\n"
" -v, --verbose display extra debugging information\n"
" -h, --help display this help and exit\n"
" -V, --version output version information and exit\n"
"\n"
"Report bugs to <anthony@codemonkey.ws>\n"
- , name);
+ , name, "DEVICE");
}
static void version(const char *name)
@@ -144,27 +152,51 @@ static int find_partition(BlockDriverSta
return -1;
}
+static void show_parts(const char *device)
+{
+ if (fork() == 0) {
+ int nbd;
+
+ /* linux just needs an open() to trigger
+ * the partition table update
+ * but remember to load the module with max_part != 0 :
+ * modprobe nbd max_part=63
+ */
+ nbd = open(device, O_RDWR);
+ if (nbd != -1)
+ close(nbd);
+ exit(0);
+ }
+}
+
int main(int argc, char **argv)
{
BlockDriverState *bs;
off_t dev_offset = 0;
off_t offset = 0;
bool readonly = false;
+ bool disconnect = false;
const char *bindto = "0.0.0.0";
int port = 1024;
int sock, csock;
struct sockaddr_in addr;
socklen_t addr_len = sizeof(addr);
off_t fd_size;
- const char *sopt = "hVbo:p:rsP:v";
+ char *device = NULL;
+ char *socket = NULL;
+ char sockpath[128];
+ const char *sopt = "hVbo:p:rsP:c:dvk:";
struct option lopt[] = {
{ "help", 0, 0, 'h' },
{ "version", 0, 0, 'V' },
{ "bind", 1, 0, 'b' },
{ "port", 1, 0, 'p' },
+ { "socket", 1, 0, 'k' },
{ "offset", 1, 0, 'o' },
{ "read-only", 0, 0, 'r' },
{ "partition", 1, 0, 'P' },
+ { "connect", 1, 0, 'c' },
+ { "disconnect", 0, 0, 'd' },
{ "snapshot", 0, 0, 's' },
{ "verbose", 0, 0, 'v' },
{ NULL, 0, 0, 0 }
@@ -175,6 +207,8 @@ int main(int argc, char **argv)
char *end;
bool snapshot = false;
int partition = -1;
+ int fd;
+ int ret;
while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
switch (ch) {
@@ -213,6 +247,17 @@ int main(int argc, char **argv)
if (partition < 1 || partition > 8)
errx(EINVAL, "Invalid partition %d", partition);
break;
+ case 'k':
+ socket = optarg;
+ if (socket[0] != '/')
+ errx(EINVAL, "socket path must be absolute\n");
+ break;
+ case 'd':
+ disconnect = true;
+ break;
+ case 'c':
+ device = optarg;
+ break;
case 'v':
verbose = 1;
break;
@@ -236,6 +281,20 @@ int main(int argc, char **argv)
argv[0]);
}
+ if (disconnect) {
+ fd = open(argv[optind], O_RDWR);
+ if (fd == -1)
+ errx(errno, "Cannot open %s", argv[optind]);
+
+ nbd_disconnect(fd);
+
+ close(fd);
+
+ printf("%s disconnected\n", argv[optind]);
+
+ return 0;
+ }
+
bdrv_init();
bs = bdrv_new("hda");
@@ -251,7 +310,77 @@ int main(int argc, char **argv)
find_partition(bs, partition, &dev_offset, &fd_size))
errx(errno, "Could not find partition %d", partition);
- sock = tcp_socket_incoming(bindto, port);
+ if (device) {
+ pid_t pid;
+ if (!verbose)
+ daemon(0, 0); /* detach client and server */
+
+ if (socket == NULL) {
+ sprintf(sockpath, SOCKET_PATH, basename(device));
+ socket = sockpath;
+ }
+
+ pid = fork();
+ if (pid < 0)
+ return 1;
+ if (pid != 0) {
+ off_t size;
+ size_t blocksize;
+
+ ret = 0;
+ bdrv_close(bs);
+
+ do {
+ sock = unix_socket_outgoing(socket);
+ if (sock == -1) {
+ if (errno != ENOENT && errno != ECONNREFUSED)
+ goto exit;
+ sleep(1); /* wait children */
+ }
+ } while (sock == -1);
+
+ fd = open(device, O_RDWR);
+ if (fd == -1) {
+ ret = 1;
+ goto exit;
+ }
+
+ ret = nbd_receive_negotiate(sock, &size, &blocksize);
+ if (ret == -1) {
+ ret = 1;
+ goto exit;
+ }
+
+ ret = nbd_init(fd, sock, size, blocksize);
+ if (ret == -1) {
+ ret = 1;
+ goto exit;
+ }
+
+ printf("NBD device %s is now connected to file %s\n",
+ device, argv[optind]);
+
+ /* update partition table */
+
+ show_parts(device);
+
+ nbd_client(fd, sock);
+ close(fd);
+exit:
+ kill(pid, SIGTERM);
+ unlink(socket);
+
+ return ret;
+ }
+ /* children */
+ }
+
+ if (socket) {
+ sock = unix_socket_incoming(socket);
+ } else {
+ sock = tcp_socket_incoming(bindto, port);
+ }
+
if (sock == -1)
return 1;
@@ -270,6 +399,8 @@ int main(int argc, char **argv)
close(csock);
close(sock);
bdrv_close(bs);
+ if (socket)
+ unlink(socket);
return 0;
}
Index: qemu/qemu-nbd.texi
===================================================================
--- qemu.orig/qemu-nbd.texi 2008-06-27 11:34:18.000000000 +0200
+++ qemu/qemu-nbd.texi 2008-06-27 11:34:35.000000000 +0200
@@ -20,10 +20,16 @@ Export Qemu disk image using NBD protoco
offset into the image
@item -b, --bind=IFACE
interface to bind to (default `0.0.0.0')
+@item -k, --socket=PATH
+ Use a unix socket with path PATH
@item -r, --read-only
export read-only
@item -P, --partition=NUM
only expose partition NUM
+@item -c, --connect
+ connect FILE to NBD device DEV
+@item -d, --disconnect
+ disconnect the specified device
@item -v, --verbose
display extra debugging information
@item -h, --help
--
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Qemu-devel] [patch 3/5] qemu-nbd: add a parameter to disable host cache.
2008-06-27 11:02 [Qemu-devel] [patch 0/5] NBD support improvement Laurent.Vivier
2008-06-27 11:02 ` [Qemu-devel] [patch 1/5] qemu-nbd: cleanup Laurent.Vivier
2008-06-27 11:02 ` [Qemu-devel] [patch 2/5] qemu-nbd: merge NBD client/server Laurent.Vivier
@ 2008-06-27 11:02 ` Laurent.Vivier
2008-06-27 11:02 ` [Qemu-devel] [patch 4/5] qemu-nbd: allow to share a disk image Laurent.Vivier
2008-06-27 11:02 ` [Qemu-devel] [patch 5/5] Allow QEMU to connect directly to an NBD server Laurent.Vivier
4 siblings, 0 replies; 10+ messages in thread
From: Laurent.Vivier @ 2008-06-27 11:02 UTC (permalink / raw)
To: qemu-devel; +Cc: Laurent.Vivier
[-- Attachment #1: qemu-nbd-direct.patch --]
[-- Type: text/plain, Size: 8602 bytes --]
This patch add a parameter "--nocache" to disable host cache for disk image.
It avoid to duplicate page for NBD device and disk image file.
---
Makefile | 5 ++++-
block-raw-posix.c | 16 ++++++++--------
nbd.c | 13 ++++---------
nbd.h | 3 ++-
qemu-nbd.c | 22 +++++++++++++++++-----
qemu-nbd.texi | 4 ++++
6 files changed, 39 insertions(+), 24 deletions(-)
Index: qemu/Makefile
===================================================================
--- qemu.orig/Makefile 2008-06-27 11:34:17.000000000 +0200
+++ qemu/Makefile 2008-06-27 11:34:38.000000000 +0200
@@ -172,8 +172,11 @@ qemu-img-%.o: %.c
%.o: %.c
$(CC) $(CFLAGS) $(CPPFLAGS) -c -o $@ $<
+qemu-nbd-%.o: %.c
+ $(CC) $(CFLAGS) $(CPPFLAGS) -DQEMU_NBD -c -o $@ $<
+
qemu-nbd$(EXESUF): qemu-nbd.o nbd.o qemu-img-block.o \
- $(QEMU_IMG_BLOCK_OBJS)
+ osdep.o qemu-nbd-block-raw-posix.o $(BLOCK_OBJS)
$(CC) $(LDFLAGS) -o $@ $^ -lz $(LIBS)
# dyngen host tool
Index: qemu/block-raw-posix.c
===================================================================
--- qemu.orig/block-raw-posix.c 2008-06-27 11:34:18.000000000 +0200
+++ qemu/block-raw-posix.c 2008-06-27 11:34:38.000000000 +0200
@@ -22,7 +22,7 @@
* THE SOFTWARE.
*/
#include "qemu-common.h"
-#ifndef QEMU_IMG
+#if !defined(QEMU_IMG) && !defined(QEMU_NBD)
#include "qemu-timer.h"
#include "exec-all.h"
#endif
@@ -59,7 +59,7 @@
//#define DEBUG_FLOPPY
//#define DEBUG_BLOCK
-#if defined(DEBUG_BLOCK) && !defined(QEMU_IMG)
+#if defined(DEBUG_BLOCK) && !defined(QEMU_IMG) && !defined(QEMU_NBD)
#define DEBUG_BLOCK_PRINT(formatCstr, args...) do { if (loglevel != 0) \
{ fprintf(logfile, formatCstr, ##args); fflush(logfile); } } while (0)
#else
@@ -434,7 +434,7 @@ static int aio_initialized = 0;
static void aio_signal_handler(int signum)
{
-#ifndef QEMU_IMG
+#if !defined(QEMU_IMG) && !defined(QEMU_NBD)
CPUState *env = cpu_single_env;
if (env) {
/* stop the currently executing cpu because a timer occured */
@@ -544,7 +544,7 @@ void qemu_aio_wait(void)
sigset_t set;
int nb_sigs;
-#ifndef QEMU_IMG
+#if !defined(QEMU_IMG) && !defined(QEMU_NBD)
if (qemu_bh_poll())
return;
#endif
@@ -586,7 +586,7 @@ static RawAIOCB *raw_aio_setup(BlockDriv
return acb;
}
-#ifndef QEMU_IMG
+#if !defined(QEMU_IMG) && !defined(QEMU_NBD)
static void raw_aio_em_cb(void* opaque)
{
RawAIOCB *acb = opaque;
@@ -605,7 +605,7 @@ static BlockDriverAIOCB *raw_aio_read(Bl
* If O_DIRECT is used and the buffer is not aligned fall back
* to synchronous IO.
*/
-#if defined(O_DIRECT) && !defined(QEMU_IMG)
+#if defined(O_DIRECT) && !defined(QEMU_IMG) && !defined(QEMU_NBD)
BDRVRawState *s = bs->opaque;
if (unlikely(s->aligned_buf != NULL && ((uintptr_t) buf % 512))) {
@@ -638,7 +638,7 @@ static BlockDriverAIOCB *raw_aio_write(B
* If O_DIRECT is used and the buffer is not aligned fall back
* to synchronous IO.
*/
-#if defined(O_DIRECT) && !defined(QEMU_IMG)
+#if defined(O_DIRECT) && !defined(QEMU_IMG) && !defined(QEMU_NBD)
BDRVRawState *s = bs->opaque;
if (unlikely(s->aligned_buf != NULL && ((uintptr_t) buf % 512))) {
@@ -941,7 +941,7 @@ static int hdev_open(BlockDriverState *b
return 0;
}
-#if defined(__linux__) && !defined(QEMU_IMG)
+#if defined(__linux__) && !defined(QEMU_IMG) && !defined(QEMU_NBD)
/* Note: we do not have a reliable method to detect if the floppy is
present. The current method is to try to open the floppy at every
Index: qemu/nbd.c
===================================================================
--- qemu.orig/nbd.c 2008-06-27 11:34:35.000000000 +0200
+++ qemu/nbd.c 2008-06-27 11:34:38.000000000 +0200
@@ -404,13 +404,8 @@ int nbd_client(int fd, int csock)
return ret;
}
-int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset, off_t *offset, bool readonly)
+int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset, off_t *offset, bool readonly, uint8_t *data, int data_size)
{
-#ifndef _REENTRANT
- static uint8_t data[1024 * 1024]; // keep this off of the stack
-#else
- uint8_t data[1024 * 1024];
-#endif
uint8_t buf[4 + 4 + 8 + 8 + 4];
uint32_t magic;
uint32_t type;
@@ -449,9 +444,9 @@ int nbd_trip(BlockDriverState *bs, int c
return -1;
}
- if (len > sizeof(data)) {
- LOG("len (%u) is larger than max len (%lu)",
- len, (unsigned long)sizeof(data));
+ if (len > data_size) {
+ LOG("len (%u) is larger than max len (%u)",
+ len, data_size);
errno = EINVAL;
return -1;
}
Index: qemu/qemu-nbd.c
===================================================================
--- qemu.orig/qemu-nbd.c 2008-06-27 11:34:35.000000000 +0200
+++ qemu/qemu-nbd.c 2008-06-27 11:34:38.000000000 +0200
@@ -34,6 +34,8 @@
#define SOCKET_PATH "/var/lock/qemu-nbd-%s"
+#define NBD_BUFFER_SIZE (1024*1024)
+
int verbose;
static void usage(const char *name)
@@ -49,6 +51,8 @@ static void usage(const char *name)
" (default '"SOCKET_PATH"')\n"
" -r, --read-only export read-only\n"
" -P, --partition=NUM only expose partition NUM\n"
+" -s, --snapshot use snapshot file\n"
+" -n, --nocache disable host cache\n"
" -c, --connect=DEV connect FILE to the local NBD device DEV\n"
" -d, --disconnect disconnect the specified device\n"
" -v, --verbose display extra debugging information\n"
@@ -185,7 +189,7 @@ int main(int argc, char **argv)
char *device = NULL;
char *socket = NULL;
char sockpath[128];
- const char *sopt = "hVbo:p:rsP:c:dvk:";
+ const char *sopt = "hVbo:p:rsnP:c:dvk:";
struct option lopt[] = {
{ "help", 0, 0, 'h' },
{ "version", 0, 0, 'V' },
@@ -198,6 +202,7 @@ int main(int argc, char **argv)
{ "connect", 1, 0, 'c' },
{ "disconnect", 0, 0, 'd' },
{ "snapshot", 0, 0, 's' },
+ { "nocache", 0, 0, 'n' },
{ "verbose", 0, 0, 'v' },
{ NULL, 0, 0, 0 }
};
@@ -205,15 +210,19 @@ int main(int argc, char **argv)
int opt_ind = 0;
int li;
char *end;
- bool snapshot = false;
+ int flags = 0;
int partition = -1;
int fd;
int ret;
+ uint8_t *data;
while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
switch (ch) {
case 's':
- snapshot = true;
+ flags |= BDRV_O_SNAPSHOT;
+ break;
+ case 'n':
+ flags |= BDRV_O_DIRECT;
break;
case 'b':
bindto = optarg;
@@ -301,7 +310,7 @@ int main(int argc, char **argv)
if (bs == NULL)
return 1;
- if (bdrv_open(bs, argv[optind], snapshot) == -1)
+ if (bdrv_open(bs, argv[optind], flags) == -1)
return 1;
fd_size = bs->total_sectors * 512;
@@ -394,7 +403,10 @@ exit:
if (nbd_negotiate(bs, csock, fd_size) == -1)
return 1;
- while (nbd_trip(bs, csock, fd_size, dev_offset, &offset, readonly) == 0);
+ data = qemu_memalign(512, NBD_BUFFER_SIZE);
+ while (nbd_trip(bs, csock, fd_size, dev_offset, &offset, readonly,
+ data, NBD_BUFFER_SIZE) == 0);
+ qemu_free(data);
close(csock);
close(sock);
Index: qemu/nbd.h
===================================================================
--- qemu.orig/nbd.h 2008-06-27 11:34:35.000000000 +0200
+++ qemu/nbd.h 2008-06-27 11:34:38.000000000 +0200
@@ -33,7 +33,8 @@ int unix_socket_incoming(const char *pat
int nbd_negotiate(BlockDriverState *bs, int csock, off_t size);
int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize);
int nbd_init(int fd, int csock, off_t size, size_t blocksize);
-int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset, off_t *offset, bool readonly);
+int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset,
+ off_t *offset, bool readonly, uint8_t *data, int data_size);
int nbd_client(int fd, int csock);
int nbd_disconnect(int fd);
Index: qemu/qemu-nbd.texi
===================================================================
--- qemu.orig/qemu-nbd.texi 2008-06-27 11:34:35.000000000 +0200
+++ qemu/qemu-nbd.texi 2008-06-27 11:34:38.000000000 +0200
@@ -26,6 +26,10 @@ Export Qemu disk image using NBD protoco
export read-only
@item -P, --partition=NUM
only expose partition NUM
+@item -s, --snapshot
+ use snapshot file
+@item -n, --nocache
+ disable host cache
@item -c, --connect
connect FILE to NBD device DEV
@item -d, --disconnect
--
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Qemu-devel] [patch 4/5] qemu-nbd: allow to share a disk image
2008-06-27 11:02 [Qemu-devel] [patch 0/5] NBD support improvement Laurent.Vivier
` (2 preceding siblings ...)
2008-06-27 11:02 ` [Qemu-devel] [patch 3/5] qemu-nbd: add a parameter to disable host cache Laurent.Vivier
@ 2008-06-27 11:02 ` Laurent.Vivier
2008-06-27 11:02 ` [Qemu-devel] [patch 5/5] Allow QEMU to connect directly to an NBD server Laurent.Vivier
4 siblings, 0 replies; 10+ messages in thread
From: Laurent.Vivier @ 2008-06-27 11:02 UTC (permalink / raw)
To: qemu-devel; +Cc: Laurent.Vivier
[-- Attachment #1: qemu-nbd-shared.patch --]
[-- Type: text/plain, Size: 6352 bytes --]
This patch allows to share a disk image using an NBD server.
You must specify by how many clients it could be shared:
server$ qemu-nbd --share=2 my_disk.qcow2
client1# nbd-client server 1024 /dev/nbd0
client2# nbd-client server 1024 /dev/nbd0
if you start a third client, it will hang until one of the previous connected
clients disconnects.
---
qemu-nbd.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++------------
qemu-nbd.texi | 2 +
2 files changed, 75 insertions(+), 19 deletions(-)
Index: qemu/qemu-nbd.c
===================================================================
--- qemu.orig/qemu-nbd.c 2008-06-27 11:34:38.000000000 +0200
+++ qemu/qemu-nbd.c 2008-06-27 11:34:41.000000000 +0200
@@ -55,6 +55,7 @@ static void usage(const char *name)
" -n, --nocache disable host cache\n"
" -c, --connect=DEV connect FILE to the local NBD device DEV\n"
" -d, --disconnect disconnect the specified device\n"
+" -e, --shared=NUM device can be shared by NUM clients (default '1')\n"
" -v, --verbose display extra debugging information\n"
" -h, --help display this help and exit\n"
" -V, --version output version information and exit\n"
@@ -182,14 +183,13 @@ int main(int argc, char **argv)
bool disconnect = false;
const char *bindto = "0.0.0.0";
int port = 1024;
- int sock, csock;
struct sockaddr_in addr;
socklen_t addr_len = sizeof(addr);
off_t fd_size;
char *device = NULL;
char *socket = NULL;
char sockpath[128];
- const char *sopt = "hVbo:p:rsnP:c:dvk:";
+ const char *sopt = "hVbo:p:rsnP:c:dvk:e:";
struct option lopt[] = {
{ "help", 0, 0, 'h' },
{ "version", 0, 0, 'V' },
@@ -203,6 +203,7 @@ int main(int argc, char **argv)
{ "disconnect", 0, 0, 'd' },
{ "snapshot", 0, 0, 's' },
{ "nocache", 0, 0, 'n' },
+ { "shared", 1, 0, 'e' },
{ "verbose", 0, 0, 'v' },
{ NULL, 0, 0, 0 }
};
@@ -212,9 +213,15 @@ int main(int argc, char **argv)
char *end;
int flags = 0;
int partition = -1;
- int fd;
int ret;
+ int shared = 1;
uint8_t *data;
+ fd_set fds;
+ int *sharing_fds;
+ int fd;
+ int i;
+ int nb_fds = 0;
+ int max_fd;
while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
switch (ch) {
@@ -267,6 +274,15 @@ int main(int argc, char **argv)
case 'c':
device = optarg;
break;
+ case 'e':
+ shared = strtol(optarg, &end, 0);
+ if (*end) {
+ errx(EINVAL, "Invalid shared device number '%s'", optarg);
+ }
+ if (shared < 1) {
+ errx(EINVAL, "Shared device number must be greater than 0\n");
+ }
+ break;
case 'v':
verbose = 1;
break;
@@ -321,6 +337,8 @@ int main(int argc, char **argv)
if (device) {
pid_t pid;
+ int sock;
+
if (!verbose)
daemon(0, 0); /* detach client and server */
@@ -384,33 +402,69 @@ exit:
/* children */
}
+ sharing_fds = qemu_malloc((shared + 1) * sizeof(int));
+ if (sharing_fds == NULL)
+ errx(ENOMEM, "Cannot allocate sharing fds");
+
if (socket) {
- sock = unix_socket_incoming(socket);
+ sharing_fds[0] = unix_socket_incoming(socket);
} else {
- sock = tcp_socket_incoming(bindto, port);
+ sharing_fds[0] = tcp_socket_incoming(bindto, port);
}
- if (sock == -1)
+ if (sharing_fds[0] == -1)
return 1;
+ max_fd = sharing_fds[0];
+ nb_fds++;
- csock = accept(sock,
- (struct sockaddr *)&addr,
- &addr_len);
- if (csock == -1)
- return 1;
+ data = qemu_memalign(512, NBD_BUFFER_SIZE);
+ if (data == NULL)
+ errx(ENOMEM, "Cannot allocate data buffer");
- /* new fd_size is calculated by find_partition */
- if (nbd_negotiate(bs, csock, fd_size) == -1)
- return 1;
+ do {
- data = qemu_memalign(512, NBD_BUFFER_SIZE);
- while (nbd_trip(bs, csock, fd_size, dev_offset, &offset, readonly,
- data, NBD_BUFFER_SIZE) == 0);
+ FD_ZERO(&fds);
+ for (i = 0; i < nb_fds; i++)
+ FD_SET(sharing_fds[i], &fds);
+
+ ret = select(max_fd + 1, &fds, NULL, NULL, NULL);
+ if (ret == -1)
+ break;
+
+ if (FD_ISSET(sharing_fds[0], &fds))
+ ret--;
+ for (i = 1; i < nb_fds && ret; i++) {
+ if (FD_ISSET(sharing_fds[i], &fds)) {
+ if (nbd_trip(bs, sharing_fds[i], fd_size, dev_offset,
+ &offset, readonly, data, NBD_BUFFER_SIZE) != 0) {
+ close(sharing_fds[i]);
+ nb_fds--;
+ sharing_fds[i] = sharing_fds[nb_fds];
+ i--;
+ }
+ ret--;
+ }
+ }
+ /* new connection ? */
+ if (FD_ISSET(sharing_fds[0], &fds)) {
+ if (nb_fds < shared + 1) {
+ sharing_fds[nb_fds] = accept(sharing_fds[0],
+ (struct sockaddr *)&addr,
+ &addr_len);
+ if (sharing_fds[nb_fds] != -1 &&
+ nbd_negotiate(bs, sharing_fds[nb_fds], fd_size) != -1) {
+ if (sharing_fds[nb_fds] > max_fd)
+ max_fd = sharing_fds[nb_fds];
+ nb_fds++;
+ }
+ }
+ }
+ } while (nb_fds > 1);
qemu_free(data);
- close(csock);
- close(sock);
+ close(sharing_fds[0]);
bdrv_close(bs);
+ qemu_free(sharing_fds);
if (socket)
unlink(socket);
Index: qemu/qemu-nbd.texi
===================================================================
--- qemu.orig/qemu-nbd.texi 2008-06-27 11:34:38.000000000 +0200
+++ qemu/qemu-nbd.texi 2008-06-27 11:34:41.000000000 +0200
@@ -34,6 +34,8 @@ Export Qemu disk image using NBD protoco
connect FILE to NBD device DEV
@item -d, --disconnect
disconnect the specified device
+@item -e, --shared=NUM
+ device can be shared by NUM clients (default '1')
@item -v, --verbose
display extra debugging information
@item -h, --help
--
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Qemu-devel] [patch 5/5] Allow QEMU to connect directly to an NBD server
2008-06-27 11:02 [Qemu-devel] [patch 0/5] NBD support improvement Laurent.Vivier
` (3 preceding siblings ...)
2008-06-27 11:02 ` [Qemu-devel] [patch 4/5] qemu-nbd: allow to share a disk image Laurent.Vivier
@ 2008-06-27 11:02 ` Laurent.Vivier
4 siblings, 0 replies; 10+ messages in thread
From: Laurent.Vivier @ 2008-06-27 11:02 UTC (permalink / raw)
To: qemu-devel; +Cc: Laurent.Vivier
[-- Attachment #1: block-nbd.patch --]
[-- Type: text/plain, Size: 22960 bytes --]
This patch add a new protocol to QEMU block interface: "nbd".
It allows to QEMU to connect to an NBD server without using kernel support
(/dev/nbd*).
example:
qemu linux.img -hdb nbd:my_nbd_server.mydomain.org:1024
If the NBD server is located on the same host, you can use an unix socket
instead of an inet socket:
qemu linux.img -hdb nbd:unix:/tmp/my_socket
In this case, the block device must be exported using qemu-nbd:
qemu-nbd --socket=/tmp/my_socket my_disk.qcow2
The use of qemu-nbd allows to share a disk between several guests:
qemu-nbd --socket=/tmp/my_socket --share=2 my_disk.qcow2
and then you can use it with two guests:
qemu linux1.img -hdb nbd:unix:/tmp/my_socket
qemu linux2.img -hdb nbd:unix:/tmp/my_socket
---
Makefile | 8 +-
block-nbd.c | 194 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
block.c | 1
block.h | 1
nbd.c | 196 ++++++++++++++++++++++++++++++++++++++++------------------
nbd.h | 22 ++++++
qemu-doc.texi | 35 ++++++++++
qemu-nbd.c | 10 ++
qemu-nbd.texi | 2
9 files changed, 403 insertions(+), 66 deletions(-)
Index: qemu/block-nbd.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ qemu/block-nbd.c 2008-06-27 11:35:14.000000000 +0200
@@ -0,0 +1,194 @@
+/*
+ * QEMU Block driver for NBD
+ *
+ * Copyright (C) 2008 Bull S.A.S.
+ * Author: Laurent Vivier <Laurent.Vivier@bull;net>
+ *
+ * Some parts:
+ * Copyright (C) 2007 Anthony Liguori <anthony@codemonkey.ws>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "qemu-common.h"
+#include "nbd.h"
+
+#include <sys/types.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <pthread.h>
+
+typedef struct BDRVNBDState {
+ int sock;
+ off_t size;
+ size_t blocksize;
+} BDRVNBDState;
+
+static int nbd_open(BlockDriverState *bs, const char* filename, int flags)
+{
+ BDRVNBDState *s = bs->opaque;
+ const char *host;
+ const char *unixpath;
+ int sock;
+ off_t size;
+ size_t blocksize;
+ int ret;
+
+ if ((flags & BDRV_O_CREAT))
+ return -EINVAL;
+
+ if (!strstart(filename, "nbd:", &host))
+ return -EINVAL;
+
+ if (strstart(host, "unix:", &unixpath)) {
+
+ if (unixpath[0] != '/')
+ return -EINVAL;
+
+ sock = unix_socket_outgoing(unixpath);
+
+ } else {
+ uint16_t port;
+ char *p, *r;
+ char hostname[128];
+
+ pstrcpy(hostname, 128, host);
+
+ p = strchr(hostname, ':');
+ if (p == NULL)
+ return -EINVAL;
+
+ *p = '\0';
+ p++;
+
+ port = strtol(p, &r, 0);
+ if (r == p)
+ return -EINVAL;
+ sock = tcp_socket_outgoing(hostname, port);
+ }
+
+ if (sock == -1)
+ return -errno;
+
+ ret = nbd_receive_negotiate(sock, &size, &blocksize);
+ if (ret == -1)
+ return -errno;
+
+ s->sock = sock;
+ s->size = size;
+ s->blocksize = blocksize;
+
+ return 0;
+}
+
+static int nbd_read(BlockDriverState *bs, int64_t sector_num,
+ uint8_t *buf, int nb_sectors)
+{
+ BDRVNBDState *s = bs->opaque;
+ struct nbd_request request;
+ struct nbd_reply reply;
+
+ request.type = NBD_CMD_READ;
+ request.handle = (uint64_t)bs;
+ request.from = sector_num * 512;;
+ request.len = nb_sectors * 512;
+
+ if (nbd_send_request(s->sock, &request) == -1)
+ return -errno;
+
+ if (nbd_receive_reply(s->sock, &reply) == -1)
+ return -errno;
+
+ if (reply.error !=0)
+ return -reply.error;
+
+ if (reply.handle != request.handle)
+ return -EIO;
+
+ if (nbd_wr_sync(s->sock, buf, request.len, 1) != request.len)
+ return -EIO;
+
+ return 0;
+}
+
+static int nbd_write(BlockDriverState *bs, int64_t sector_num,
+ const uint8_t *buf, int nb_sectors)
+{
+ BDRVNBDState *s = bs->opaque;
+ struct nbd_request request;
+ struct nbd_reply reply;
+
+ request.type = NBD_CMD_WRITE;
+ request.handle = (uint64_t)bs;
+ request.from = sector_num * 512;;
+ request.len = nb_sectors * 512;
+
+ if (nbd_send_request(s->sock, &request) == -1)
+ return -errno;
+
+ if (nbd_wr_sync(s->sock, (uint8_t*)buf, request.len, 0) != request.len)
+ return -EIO;
+
+ if (nbd_receive_reply(s->sock, &reply) == -1)
+ return -errno;
+
+ if (reply.error !=0)
+ return -reply.error;
+
+ if (reply.handle != request.handle)
+ return -EIO;
+
+ return 0;
+}
+
+static void nbd_close(BlockDriverState *bs)
+{
+ BDRVNBDState *s = bs->opaque;
+ struct nbd_request request;
+
+ request.type = NBD_CMD_DISC;
+ request.handle = (uint64_t)bs;
+ request.from = 0;
+ request.len = 0;
+ nbd_send_request(s->sock, &request);
+
+ close(s->sock);
+}
+
+static int64_t nbd_getlength(BlockDriverState *bs)
+{
+ BDRVNBDState *s = bs->opaque;
+
+ return s->size;
+}
+
+BlockDriver bdrv_nbd = {
+ "nbd",
+ sizeof(BDRVNBDState),
+ NULL, /* no probe for protocols */
+ nbd_open,
+ nbd_read,
+ nbd_write,
+ nbd_close,
+ .bdrv_getlength = nbd_getlength,
+ .protocol_name = "nbd",
+};
Index: qemu/Makefile
===================================================================
--- qemu.orig/Makefile 2008-06-27 11:35:11.000000000 +0200
+++ qemu/Makefile 2008-06-27 11:35:14.000000000 +0200
@@ -42,7 +42,7 @@ recurse-all: $(SUBDIR_RULES)
BLOCK_OBJS=cutils.o qemu-malloc.o
BLOCK_OBJS+=block-cow.o block-qcow.o aes.o block-vmdk.o block-cloop.o
BLOCK_OBJS+=block-dmg.o block-bochs.o block-vpc.o block-vvfat.o
-BLOCK_OBJS+=block-qcow2.o block-parallels.o
+BLOCK_OBJS+=block-qcow2.o block-parallels.o block-nbd.o
######################################################################
# libqemu_common.a: Target independent part of system emulation. The
@@ -50,7 +50,7 @@ BLOCK_OBJS+=block-qcow2.o block-parallel
# system emulation, i.e. a single QEMU executable should support all
# CPUs and machines.
-OBJS=$(BLOCK_OBJS)
+OBJS=nbd.o $(BLOCK_OBJS)
OBJS+=readline.o console.o
OBJS+=block.o
@@ -154,7 +154,7 @@ libqemu_user.a: $(USER_OBJS)
rm -f $@
$(AR) rcs $@ $(USER_OBJS)
-QEMU_IMG_BLOCK_OBJS = $(BLOCK_OBJS)
+QEMU_IMG_BLOCK_OBJS = nbd.o $(BLOCK_OBJS)
ifdef CONFIG_WIN32
QEMU_IMG_BLOCK_OBJS += qemu-img-block-raw-win32.o
else
@@ -175,7 +175,7 @@ qemu-img-%.o: %.c
qemu-nbd-%.o: %.c
$(CC) $(CFLAGS) $(CPPFLAGS) -DQEMU_NBD -c -o $@ $<
-qemu-nbd$(EXESUF): qemu-nbd.o nbd.o qemu-img-block.o \
+qemu-nbd$(EXESUF): qemu-nbd.o qemu-nbd-nbd.o qemu-img-block.o \
osdep.o qemu-nbd-block-raw-posix.o $(BLOCK_OBJS)
$(CC) $(LDFLAGS) -o $@ $^ -lz $(LIBS)
Index: qemu/nbd.c
===================================================================
--- qemu.orig/nbd.c 2008-06-27 11:35:11.000000000 +0200
+++ qemu/nbd.c 2008-06-27 11:35:14.000000000 +0200
@@ -31,17 +31,21 @@
#include <arpa/inet.h>
#include <netdb.h>
+#if defined(QEMU_NBD)
extern int verbose;
+#else
+static int verbose = 0;
+#endif
+
+#define TRACE(msg, ...) do { \
+ if (verbose) LOG(msg, ## __VA_ARGS__); \
+} while(0)
#define LOG(msg, ...) do { \
fprintf(stderr, "%s:%s():L%d: " msg "\n", \
__FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \
} while(0)
-#define TRACE(msg, ...) do { \
- if (verbose) LOG(msg, ## __VA_ARGS__); \
-} while(0)
-
/* This is all part of the "official" NBD API */
#define NBD_REQUEST_MAGIC 0x25609513
@@ -59,10 +63,10 @@ extern int verbose;
/* That's all folks */
-#define read_sync(fd, buffer, size) wr_sync(fd, buffer, size, true)
-#define write_sync(fd, buffer, size) wr_sync(fd, buffer, size, false)
+#define read_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, true)
+#define write_sync(fd, buffer, size) nbd_wr_sync(fd, buffer, size, false)
-static size_t wr_sync(int fd, void *buffer, size_t size, bool do_read)
+size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read)
{
size_t offset = 0;
@@ -76,7 +80,7 @@ static size_t wr_sync(int fd, void *buff
}
/* recoverable error */
- if (len == -1 && errno == EAGAIN) {
+ if (len == -1 && (errno == EAGAIN || errno == EINTR)) {
continue;
}
@@ -96,7 +100,7 @@ static size_t wr_sync(int fd, void *buff
return offset;
}
-static int tcp_socket_outgoing(const char *address, uint16_t port)
+int tcp_socket_outgoing(const char *address, uint16_t port)
{
int s;
struct in_addr in;
@@ -404,15 +408,31 @@ int nbd_client(int fd, int csock)
return ret;
}
-int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset, off_t *offset, bool readonly, uint8_t *data, int data_size)
+int nbd_send_request(int csock, struct nbd_request *request)
{
uint8_t buf[4 + 4 + 8 + 8 + 4];
- uint32_t magic;
- uint32_t type;
- uint64_t from;
- uint32_t len;
- TRACE("Reading request.");
+ cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
+ cpu_to_be32w((uint32_t*)(buf + 4), request->type);
+ cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
+ cpu_to_be64w((uint64_t*)(buf + 16), request->from);
+ cpu_to_be32w((uint32_t*)(buf + 24), request->len);
+
+ TRACE("Sending request to client");
+
+ if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
+ LOG("writing to socket failed");
+ errno = EINVAL;
+ return -1;
+ }
+ return 0;
+}
+
+
+static int nbd_receive_request(int csock, struct nbd_request *request)
+{
+ uint8_t buf[4 + 4 + 8 + 8 + 4];
+ uint32_t magic;
if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
LOG("read failed");
@@ -429,89 +449,150 @@ int nbd_trip(BlockDriverState *bs, int c
*/
magic = be32_to_cpup((uint32_t*)buf);
- type = be32_to_cpup((uint32_t*)(buf + 4));
- from = be64_to_cpup((uint64_t*)(buf + 16));
- len = be32_to_cpup((uint32_t*)(buf + 24));
+ request->type = be32_to_cpup((uint32_t*)(buf + 4));
+ request->handle = be64_to_cpup((uint64_t*)(buf + 8));
+ request->from = be64_to_cpup((uint64_t*)(buf + 16));
+ request->len = be32_to_cpup((uint32_t*)(buf + 24));
TRACE("Got request: "
"{ magic = 0x%x, .type = %d, from = %" PRIu64" , len = %u }",
- magic, type, from, len);
-
+ magic, request->type, request->from, request->len);
if (magic != NBD_REQUEST_MAGIC) {
LOG("invalid magic (got 0x%x)", magic);
errno = EINVAL;
return -1;
}
+}
+
+int nbd_receive_reply(int csock, struct nbd_reply *reply)
+{
+ uint8_t buf[4 + 4 + 8];
+ uint32_t magic;
+int i;
+
+for (i = 0; i < sizeof(buf); i++) buf[i] = 0xAA;
+
+ if (read_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
+ LOG("read failed");
+ errno = EINVAL;
+ return -1;
+ }
- if (len > data_size) {
+ /* Reply
+ [ 0 .. 3] magic (NBD_REPLY_MAGIC)
+ [ 4 .. 7] error (0 == no error)
+ [ 7 .. 15] handle
+ */
+
+ magic = be32_to_cpup((uint32_t*)buf);
+ reply->error = be32_to_cpup((uint32_t*)(buf + 4));
+ reply->handle = be64_to_cpup((uint64_t*)(buf + 8));
+
+ TRACE("Got reply: "
+ "{ magic = 0x%x, .error = %d, handle = %" PRIu64" }",
+ magic, reply->error, reply->handle);
+
+ if (magic != NBD_REPLY_MAGIC) {
+ LOG("invalid magic (got 0x%x)", magic);
+ errno = EINVAL;
+ return -1;
+ }
+ return 0;
+}
+
+static int nbd_send_reply(int csock, struct nbd_reply *reply)
+{
+ uint8_t buf[4 + 4 + 8];
+
+ /* Reply
+ [ 0 .. 3] magic (NBD_REPLY_MAGIC)
+ [ 4 .. 7] error (0 == no error)
+ [ 7 .. 15] handle
+ */
+ cpu_to_be32w((uint32_t*)buf, NBD_REPLY_MAGIC);
+ cpu_to_be32w((uint32_t*)(buf + 4), reply->error);
+ cpu_to_be64w((uint64_t*)(buf + 8), reply->handle);
+
+ TRACE("Sending response to client");
+
+ if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
+ LOG("writing to socket failed");
+ errno = EINVAL;
+ return -1;
+ }
+ return 0;
+}
+
+int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset, off_t *offset, bool readonly, uint8_t *data, int data_size)
+{
+ struct nbd_request request;
+ struct nbd_reply reply;
+
+ TRACE("Reading request.");
+
+ if (nbd_receive_request(csock, &request) == -1)
+ return -1;
+
+ if (request.len > data_size) {
LOG("len (%u) is larger than max len (%u)",
- len, data_size);
+ request.len, data_size);
errno = EINVAL;
return -1;
}
- if ((from + len) < from) {
+ if ((request.from + request.len) < request.from) {
LOG("integer overflow detected! "
"you're probably being attacked");
errno = EINVAL;
return -1;
}
- if ((from + len) > size) {
+ if ((request.from + request.len) > size) {
LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
", Offset: %" PRIu64 "\n",
- from, len, size, dev_offset);
+ request.from, request.len, size, dev_offset);
LOG("requested operation past EOF--bad client?");
errno = EINVAL;
return -1;
}
- /* Reply
- [ 0 .. 3] magic (NBD_REPLY_MAGIC)
- [ 4 .. 7] error (0 == no error)
- [ 7 .. 15] handle
- */
- cpu_to_be32w((uint32_t*)buf, NBD_REPLY_MAGIC);
- cpu_to_be32w((uint32_t*)(buf + 4), 0);
-
TRACE("Decoding type");
- switch (type) {
- case 0:
+ reply.handle = request.handle;
+ reply.error = 0;
+
+ switch (request.type) {
+ case NBD_CMD_READ:
TRACE("Request type is READ");
- if (bdrv_read(bs, (from + dev_offset) / 512, data, len / 512) == -1) {
+ if (bdrv_read(bs, (request.from + dev_offset) / 512, data,
+ request.len / 512) == -1) {
LOG("reading from file failed");
errno = EINVAL;
return -1;
}
- *offset += len;
-
- TRACE("Read %u byte(s)", len);
+ *offset += request.len;
- TRACE("Sending OK response");
+ TRACE("Read %u byte(s)", request.len);
- if (write_sync(csock, buf, 16) != 16) {
- LOG("writing to socket failed");
- errno = EINVAL;
+ if (nbd_send_reply(csock, &reply) == -1)
return -1;
- }
TRACE("Sending data to client");
- if (write_sync(csock, data, len) != len) {
+ if (write_sync(csock, data, request.len) != request.len) {
LOG("writing to socket failed");
errno = EINVAL;
return -1;
}
break;
- case 1:
+ case NBD_CMD_WRITE:
TRACE("Request type is WRITE");
- TRACE("Reading %u byte(s)", len);
+ TRACE("Reading %u byte(s)", request.len);
- if (read_sync(csock, data, len) != len) {
+ if (read_sync(csock, data, request.len) != request.len) {
LOG("reading from socket failed");
errno = EINVAL;
return -1;
@@ -519,34 +600,29 @@ int nbd_trip(BlockDriverState *bs, int c
if (readonly) {
TRACE("Server is read-only, return error");
-
- cpu_to_be32w((uint32_t*)(buf + 4), 1);
+ reply.error = 1;
} else {
TRACE("Writing to device");
- if (bdrv_write(bs, (from + dev_offset) / 512, data, len / 512) == -1) {
+ if (bdrv_write(bs, (request.from + dev_offset) / 512,
+ data, request.len / 512) == -1) {
LOG("writing to file failed");
errno = EINVAL;
return -1;
}
- *offset += len;
+ *offset += request.len;
}
- TRACE("Sending response to client");
-
- if (write_sync(csock, buf, 16) != 16) {
- LOG("writing to socket failed");
- errno = EINVAL;
+ if (nbd_send_reply(csock, &reply) == -1)
return -1;
- }
break;
- case 2:
+ case NBD_CMD_DISC:
TRACE("Request type is DISCONNECT");
errno = 0;
return 1;
default:
- LOG("invalid request type (%u) received", type);
+ LOG("invalid request type (%u) received", request.type);
errno = EINVAL;
return -1;
}
Index: qemu/nbd.h
===================================================================
--- qemu.orig/nbd.h 2008-06-27 11:35:11.000000000 +0200
+++ qemu/nbd.h 2008-06-27 11:35:14.000000000 +0200
@@ -26,6 +26,26 @@
#include <qemu-common.h>
#include "block_int.h"
+struct nbd_request {
+ uint32_t type;
+ uint64_t handle;
+ uint64_t from;
+ uint32_t len;
+};
+
+struct nbd_reply {
+ uint32_t error;
+ uint64_t handle;
+};
+
+enum {
+ NBD_CMD_READ = 0,
+ NBD_CMD_WRITE = 1,
+ NBD_CMD_DISC = 2
+};
+
+size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read);
+int tcp_socket_outgoing(const char *address, uint16_t port);
int tcp_socket_incoming(const char *address, uint16_t port);
int unix_socket_outgoing(const char *path);
int unix_socket_incoming(const char *path);
@@ -33,6 +53,8 @@ int unix_socket_incoming(const char *pat
int nbd_negotiate(BlockDriverState *bs, int csock, off_t size);
int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize);
int nbd_init(int fd, int csock, off_t size, size_t blocksize);
+int nbd_send_request(int csock, struct nbd_request *request);
+int nbd_receive_reply(int csock, struct nbd_reply *reply);
int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset,
off_t *offset, bool readonly, uint8_t *data, int data_size);
int nbd_client(int fd, int csock);
Index: qemu/block.c
===================================================================
--- qemu.orig/block.c 2008-06-27 11:35:11.000000000 +0200
+++ qemu/block.c 2008-06-27 11:35:14.000000000 +0200
@@ -1332,6 +1332,7 @@ void bdrv_init(void)
bdrv_register(&bdrv_vvfat);
bdrv_register(&bdrv_qcow2);
bdrv_register(&bdrv_parallels);
+ bdrv_register(&bdrv_nbd);
}
void *qemu_aio_get(BlockDriverState *bs, BlockDriverCompletionFunc *cb,
Index: qemu/block.h
===================================================================
--- qemu.orig/block.h 2008-06-27 11:35:11.000000000 +0200
+++ qemu/block.h 2008-06-27 11:35:14.000000000 +0200
@@ -16,6 +16,7 @@ extern BlockDriver bdrv_vpc;
extern BlockDriver bdrv_vvfat;
extern BlockDriver bdrv_qcow2;
extern BlockDriver bdrv_parallels;
+extern BlockDriver bdrv_nbd;
typedef struct BlockDriverInfo {
/* in bytes, 0 if irrelevant */
Index: qemu/qemu-nbd.c
===================================================================
--- qemu.orig/qemu-nbd.c 2008-06-27 11:35:11.000000000 +0200
+++ qemu/qemu-nbd.c 2008-06-27 11:35:14.000000000 +0200
@@ -56,6 +56,7 @@ static void usage(const char *name)
" -c, --connect=DEV connect FILE to the local NBD device DEV\n"
" -d, --disconnect disconnect the specified device\n"
" -e, --shared=NUM device can be shared by NUM clients (default '1')\n"
+" -t, --persistent don't exit on the last connection\n"
" -v, --verbose display extra debugging information\n"
" -h, --help display this help and exit\n"
" -V, --version output version information and exit\n"
@@ -189,7 +190,7 @@ int main(int argc, char **argv)
char *device = NULL;
char *socket = NULL;
char sockpath[128];
- const char *sopt = "hVbo:p:rsnP:c:dvk:e:";
+ const char *sopt = "hVbo:p:rsnP:c:dvk:e:t";
struct option lopt[] = {
{ "help", 0, 0, 'h' },
{ "version", 0, 0, 'V' },
@@ -204,6 +205,7 @@ int main(int argc, char **argv)
{ "snapshot", 0, 0, 's' },
{ "nocache", 0, 0, 'n' },
{ "shared", 1, 0, 'e' },
+ { "persistent", 0, 0, 't' },
{ "verbose", 0, 0, 'v' },
{ NULL, 0, 0, 0 }
};
@@ -222,6 +224,7 @@ int main(int argc, char **argv)
int i;
int nb_fds = 0;
int max_fd;
+ int persistent = 0;
while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
switch (ch) {
@@ -283,6 +286,9 @@ int main(int argc, char **argv)
errx(EINVAL, "Shared device number must be greater than 0\n");
}
break;
+ case 't':
+ persistent = 1;
+ break;
case 'v':
verbose = 1;
break;
@@ -459,7 +465,7 @@ exit:
}
}
}
- } while (nb_fds > 1);
+ } while (persistent || nb_fds > 1);
qemu_free(data);
close(sharing_fds[0]);
Index: qemu/qemu-nbd.texi
===================================================================
--- qemu.orig/qemu-nbd.texi 2008-06-27 11:35:11.000000000 +0200
+++ qemu/qemu-nbd.texi 2008-06-27 11:35:14.000000000 +0200
@@ -36,6 +36,8 @@ Export Qemu disk image using NBD protoco
disconnect the specified device
@item -e, --shared=NUM
device can be shared by NUM clients (default '1')
+@item -t, --persistent
+ don't exit on the last connection
@item -v, --verbose
display extra debugging information
@item -h, --help
Index: qemu/qemu-doc.texi
===================================================================
--- qemu.orig/qemu-doc.texi 2008-06-27 11:35:11.000000000 +0200
+++ qemu/qemu-doc.texi 2008-06-27 11:35:14.000000000 +0200
@@ -1310,6 +1310,7 @@ snapshots.
* qemu_nbd_invocation:: qemu-nbd Invocation
* host_drives:: Using host drives
* disk_images_fat_images:: Virtual FAT disk images
+* disk_images_nbd:: NBD access
@end menu
@node disk_images_quickstart
@@ -1492,6 +1493,40 @@ What you should @emph{never} do:
@item write to the FAT directory on the host system while accessing it with the guest system.
@end itemize
+@node disk_images_nbd
+@subsection NBD access
+
+QEMU can access directly to block device exported using the Network Block Device
+protocol.
+
+@example
+qemu linux.img -hdb nbd:my_nbd_server.mydomain.org:1024
+@end example
+
+If the NBD server is located on the same host, you can use an unix socket instead
+of an inet socket:
+
+@example
+qemu linux.img -hdb nbd:unix:/tmp/my_socket
+@end example
+
+In this case, the block device must be exported using qemu-nbd:
+
+@example
+qemu-nbd --socket=/tmp/my_socket my_disk.qcow2
+@end example
+
+The use of qemu-nbd allows to share a disk between several guests:
+@example
+qemu-nbd --socket=/tmp/my_socket --share=2 my_disk.qcow2
+@end example
+
+and then you can use it with two guests:
+@example
+qemu linux1.img -hdb nbd:unix:/tmp/my_socket
+qemu linux2.img -hdb nbd:unix:/tmp/my_socket
+@end example
+
@node pcsys_network
@section Network emulation
--
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Qemu-devel] [patch 2/5] qemu-nbd: merge NBD client/server
2008-06-27 11:02 ` [Qemu-devel] [patch 2/5] qemu-nbd: merge NBD client/server Laurent.Vivier
@ 2008-07-02 21:26 ` Thiemo Seufer
2008-07-03 7:21 ` Kevin Wolf
0 siblings, 1 reply; 10+ messages in thread
From: Thiemo Seufer @ 2008-07-02 21:26 UTC (permalink / raw)
To: qemu-devel; +Cc: Laurent.Vivier
Laurent.Vivier@bull.net wrote:
> This patch allows to connect directly a disk image file to an NBD
> device. It introduces the use of a unix socket (instead of inet).
>
> - To connect a file to a device:
>
> # qemu-nbd --connect=/dev/nbd0 my_disk.qcow2
>
> Then you can see directly your disk (no need of nbd-client):
>
> # fdisk -l /dev/nbd0
>
> Disk /dev/nbd0: 4294 MB, 4294967296 bytes
> 255 heads, 63 sectors/track, 522 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>
> Device Boot Start End Blocks Id System
> /dev/nbd0p1 * 1 492 3951958+ 83 Linux
> /dev/nbd0p2 493 522 240975 5 Extended
> /dev/nbd0p5 493 522 240943+ 82 Linux swap /
> Solaris
>
> - To disconnect the file from the device:
>
> # qemu-nbd --disconnect /dev/nbd0
>
> Changelog:
> - v2: call show_parts() from client and avoid the sleep(1). Thank you to
> Avi and Anthony. Include my cleanup patch and comments from Carlo
> Marcelo Arenas Belon.
> - v3: allow to specify unix socket name with "--socket" and update
> documentation.
There's still a call to sleep() in this patch.
Thiemo
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Qemu-devel] [patch 2/5] qemu-nbd: merge NBD client/server
2008-07-02 21:26 ` Thiemo Seufer
@ 2008-07-03 7:21 ` Kevin Wolf
2008-07-03 8:13 ` Laurent Vivier
0 siblings, 1 reply; 10+ messages in thread
From: Kevin Wolf @ 2008-07-03 7:21 UTC (permalink / raw)
To: qemu-devel; +Cc: Laurent.Vivier
Thiemo Seufer schrieb:
> Laurent.Vivier@bull.net wrote:
>> This patch allows to connect directly a disk image file to an NBD
>> device. It introduces the use of a unix socket (instead of inet).
>>
>> - To connect a file to a device:
>>
>> # qemu-nbd --connect=/dev/nbd0 my_disk.qcow2
>>
>> Then you can see directly your disk (no need of nbd-client):
>>
>> # fdisk -l /dev/nbd0
>>
>> Disk /dev/nbd0: 4294 MB, 4294967296 bytes
>> 255 heads, 63 sectors/track, 522 cylinders
>> Units = cylinders of 16065 * 512 = 8225280 bytes
>>
>> Device Boot Start End Blocks Id System
>> /dev/nbd0p1 * 1 492 3951958+ 83 Linux
>> /dev/nbd0p2 493 522 240975 5 Extended
>> /dev/nbd0p5 493 522 240943+ 82 Linux swap /
>> Solaris
>>
>> - To disconnect the file from the device:
>>
>> # qemu-nbd --disconnect /dev/nbd0
>>
>> Changelog:
>> - v2: call show_parts() from client and avoid the sleep(1). Thank you to
>> Avi and Anthony. Include my cleanup patch and comments from Carlo
>> Marcelo Arenas Belon.
>> - v3: allow to specify unix socket name with "--socket" and update
>> documentation.
>
> There's still a call to sleep() in this patch.
And that's fine, IMHO. sleep() is not bad per se. The remaining call is
not a "guess it'll take at most a second" style sleep but waiting in a
loop until the child is ready. You don't want the loop to eat up 100%
CPU, do you?
Kevin
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Qemu-devel] [patch 2/5] qemu-nbd: merge NBD client/server
2008-07-03 7:21 ` Kevin Wolf
@ 2008-07-03 8:13 ` Laurent Vivier
2008-07-03 10:27 ` Thiemo Seufer
0 siblings, 1 reply; 10+ messages in thread
From: Laurent Vivier @ 2008-07-03 8:13 UTC (permalink / raw)
To: Kevin Wolf; +Cc: qemu-devel
Le jeudi 03 juillet 2008 à 09:21 +0200, Kevin Wolf a écrit :
> Thiemo Seufer schrieb:
> > Laurent.Vivier@bull.net wrote:
> >> This patch allows to connect directly a disk image file to an NBD
> >> device. It introduces the use of a unix socket (instead of inet).
> >>
> >> - To connect a file to a device:
> >>
> >> # qemu-nbd --connect=/dev/nbd0 my_disk.qcow2
> >>
> >> Then you can see directly your disk (no need of nbd-client):
> >>
> >> # fdisk -l /dev/nbd0
> >>
> >> Disk /dev/nbd0: 4294 MB, 4294967296 bytes
> >> 255 heads, 63 sectors/track, 522 cylinders
> >> Units = cylinders of 16065 * 512 = 8225280 bytes
> >>
> >> Device Boot Start End Blocks Id System
> >> /dev/nbd0p1 * 1 492 3951958+ 83 Linux
> >> /dev/nbd0p2 493 522 240975 5 Extended
> >> /dev/nbd0p5 493 522 240943+ 82 Linux swap /
> >> Solaris
> >>
> >> - To disconnect the file from the device:
> >>
> >> # qemu-nbd --disconnect /dev/nbd0
> >>
> >> Changelog:
> >> - v2: call show_parts() from client and avoid the sleep(1). Thank you to
> >> Avi and Anthony. Include my cleanup patch and comments from Carlo
> >> Marcelo Arenas Belon.
> >> - v3: allow to specify unix socket name with "--socket" and update
> >> documentation.
> >
> > There's still a call to sleep() in this patch.
>
> And that's fine, IMHO. sleep() is not bad per se. The remaining call is
> not a "guess it'll take at most a second" style sleep but waiting in a
> loop until the child is ready. You don't want the loop to eat up 100%
> CPU, do you?
I agree.
Laurent
--
------------- Laurent.Vivier@bull.net ---------------
"The best way to predict the future is to invent it."
- Alan Kay
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Qemu-devel] [patch 2/5] qemu-nbd: merge NBD client/server
2008-07-03 8:13 ` Laurent Vivier
@ 2008-07-03 10:27 ` Thiemo Seufer
0 siblings, 0 replies; 10+ messages in thread
From: Thiemo Seufer @ 2008-07-03 10:27 UTC (permalink / raw)
To: Laurent Vivier; +Cc: Kevin Wolf, qemu-devel
Laurent Vivier wrote:
> Le jeudi 03 juillet 2008 à 09:21 +0200, Kevin Wolf a écrit :
> > Thiemo Seufer schrieb:
> > > Laurent.Vivier@bull.net wrote:
> > >> This patch allows to connect directly a disk image file to an NBD
> > >> device. It introduces the use of a unix socket (instead of inet).
> > >>
> > >> - To connect a file to a device:
> > >>
> > >> # qemu-nbd --connect=/dev/nbd0 my_disk.qcow2
> > >>
> > >> Then you can see directly your disk (no need of nbd-client):
> > >>
> > >> # fdisk -l /dev/nbd0
> > >>
> > >> Disk /dev/nbd0: 4294 MB, 4294967296 bytes
> > >> 255 heads, 63 sectors/track, 522 cylinders
> > >> Units = cylinders of 16065 * 512 = 8225280 bytes
> > >>
> > >> Device Boot Start End Blocks Id System
> > >> /dev/nbd0p1 * 1 492 3951958+ 83 Linux
> > >> /dev/nbd0p2 493 522 240975 5 Extended
> > >> /dev/nbd0p5 493 522 240943+ 82 Linux swap /
> > >> Solaris
> > >>
> > >> - To disconnect the file from the device:
> > >>
> > >> # qemu-nbd --disconnect /dev/nbd0
> > >>
> > >> Changelog:
> > >> - v2: call show_parts() from client and avoid the sleep(1). Thank you to
> > >> Avi and Anthony. Include my cleanup patch and comments from Carlo
> > >> Marcelo Arenas Belon.
> > >> - v3: allow to specify unix socket name with "--socket" and update
> > >> documentation.
> > >
> > > There's still a call to sleep() in this patch.
> >
> > And that's fine, IMHO. sleep() is not bad per se. The remaining call is
> > not a "guess it'll take at most a second" style sleep but waiting in a
> > loop until the child is ready. You don't want the loop to eat up 100%
> > CPU, do you?
>
> I agree.
I committed it with a small change (exit is not the best name for a label).
Thiemo
^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2008-07-03 10:27 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-06-27 11:02 [Qemu-devel] [patch 0/5] NBD support improvement Laurent.Vivier
2008-06-27 11:02 ` [Qemu-devel] [patch 1/5] qemu-nbd: cleanup Laurent.Vivier
2008-06-27 11:02 ` [Qemu-devel] [patch 2/5] qemu-nbd: merge NBD client/server Laurent.Vivier
2008-07-02 21:26 ` Thiemo Seufer
2008-07-03 7:21 ` Kevin Wolf
2008-07-03 8:13 ` Laurent Vivier
2008-07-03 10:27 ` Thiemo Seufer
2008-06-27 11:02 ` [Qemu-devel] [patch 3/5] qemu-nbd: add a parameter to disable host cache Laurent.Vivier
2008-06-27 11:02 ` [Qemu-devel] [patch 4/5] qemu-nbd: allow to share a disk image Laurent.Vivier
2008-06-27 11:02 ` [Qemu-devel] [patch 5/5] Allow QEMU to connect directly to an NBD server Laurent.Vivier
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