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qemu-nbd: introduce NBDRequest 

Move the buffer from NBDExport to a new structure, so that it will be
possible to have multiple in-flight requests for the same export
(and for the same client too---we get that for free).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2011-09-19 14:18:33 +02:00
parent af49bbbe78
commit d9a7380658
1 changed files with 51 additions and 14 deletions
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65
nbd.c
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@ -36,6 +36,7 @@
#endif
#include "qemu_socket.h"
#include "qemu-queue.h"
//#define DEBUG_NBD
@ -584,29 +585,60 @@ static int nbd_send_reply(int csock, struct nbd_reply *reply)
return 0;
}
typedef struct NBDRequest NBDRequest;
struct NBDRequest {
QSIMPLEQ_ENTRY(NBDRequest) entry;
uint8_t *data;
};
struct NBDExport {
BlockDriverState *bs;
off_t dev_offset;
off_t size;
uint8_t *data;
uint32_t nbdflags;
QSIMPLEQ_HEAD(, NBDRequest) requests;
};
static NBDRequest *nbd_request_get(NBDExport *exp)
{
NBDRequest *req;
if (QSIMPLEQ_EMPTY(&exp->requests)) {
req = g_malloc0(sizeof(NBDRequest));
req->data = qemu_blockalign(exp->bs, NBD_BUFFER_SIZE);
} else {
req = QSIMPLEQ_FIRST(&exp->requests);
QSIMPLEQ_REMOVE_HEAD(&exp->requests, entry);
}
return req;
}
static void nbd_request_put(NBDExport *exp, NBDRequest *req)
{
QSIMPLEQ_INSERT_HEAD(&exp->requests, req, entry);
}
NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset,
off_t size, uint32_t nbdflags)
{
NBDExport *exp = g_malloc0(sizeof(NBDExport));
QSIMPLEQ_INIT(&exp->requests);
exp->bs = bs;
exp->dev_offset = dev_offset;
exp->nbdflags = nbdflags;
exp->size = size == -1 ? exp->bs->total_sectors * 512 : size;
exp->data = qemu_blockalign(exp->bs, NBD_BUFFER_SIZE);
return exp;
}
void nbd_export_close(NBDExport *exp)
{
qemu_vfree(exp->data);
while (!QSIMPLEQ_EMPTY(&exp->requests)) {
NBDRequest *first = QSIMPLEQ_FIRST(&exp->requests);
QSIMPLEQ_REMOVE_HEAD(&exp->requests, entry);
qemu_vfree(first->data);
g_free(first);
}
bdrv_close(exp->bs);
g_free(exp);
}
@ -682,15 +714,17 @@ out:
int nbd_trip(NBDExport *exp, int csock)
{
NBDRequest *req = nbd_request_get(exp);
struct nbd_request request;
struct nbd_reply reply;
int rc = -1;
int ret;
TRACE("Reading request.");
ret = nbd_do_receive_request(csock, &request, exp->data);
ret = nbd_do_receive_request(csock, &request, req->data);
if (ret == -EIO) {
return -1;
goto out;
}
reply.handle = request.handle;
@ -715,7 +749,7 @@ int nbd_trip(NBDExport *exp, int csock)
TRACE("Request type is READ");
ret = bdrv_read(exp->bs, (request.from + exp->dev_offset) / 512,
exp->data, request.len / 512);
req->data, request.len / 512);
if (ret < 0) {
LOG("reading from file failed");
reply.error = -ret;
@ -723,8 +757,8 @@ int nbd_trip(NBDExport *exp, int csock)
}
TRACE("Read %u byte(s)", request.len);
if (nbd_do_send_reply(csock, &reply, exp->data, request.len) < 0)
return -1;
if (nbd_do_send_reply(csock, &reply, req->data, request.len) < 0)
goto out;
break;
case NBD_CMD_WRITE:
TRACE("Request type is WRITE");
@ -738,7 +772,7 @@ int nbd_trip(NBDExport *exp, int csock)
TRACE("Writing to device");
ret = bdrv_write(exp->bs, (request.from + exp->dev_offset) / 512,
exp->data, request.len / 512);
req->data, request.len / 512);
if (ret < 0) {
LOG("writing to file failed");
reply.error = -ret;
@ -755,7 +789,7 @@ int nbd_trip(NBDExport *exp, int csock)
}
if (nbd_do_send_reply(csock, &reply, NULL, 0) < 0)
return -1;
goto out;
break;
case NBD_CMD_DISC:
TRACE("Request type is DISCONNECT");
@ -771,7 +805,7 @@ int nbd_trip(NBDExport *exp, int csock)
}
if (nbd_do_send_reply(csock, &reply, NULL, 0) < 0)
return -1;
goto out;
break;
case NBD_CMD_TRIM:
TRACE("Request type is TRIM");
@ -782,7 +816,7 @@ int nbd_trip(NBDExport *exp, int csock)
reply.error = -ret;
}
if (nbd_do_send_reply(csock, &reply, NULL, 0) < 0)
return -1;
goto out;
break;
default:
LOG("invalid request type (%u) received", request.type);
@ -790,13 +824,16 @@ int nbd_trip(NBDExport *exp, int csock)
reply.error = -EINVAL;
error_reply:
if (nbd_do_send_reply(csock, &reply, NULL, 0) == -1)
return -1;
goto out;
break;
}
TRACE("Request/Reply complete");
return 0;
rc = 0;
out:
nbd_request_put(exp, req);
return rc;
}
int nbd_negotiate(NBDExport *exp, int csock)