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[Qemu-devel] [PATCH 04/26] nbd: split requests
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 04/26] nbd: split requests |
Date: |
Fri, 23 Dec 2011 16:26:08 +0100 |
qemu-nbd has a limit of slightly less than 1M per request. Work
around this in the nbd block driver.
Signed-off-by: Paolo Bonzini <address@hidden>
---
block/nbd.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++------
1 files changed, 46 insertions(+), 6 deletions(-)
diff --git a/block/nbd.c b/block/nbd.c
index bea7acd..9d661c1 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -277,8 +277,9 @@ static int nbd_open(BlockDriverState *bs, const char*
filename, int flags)
return result;
}
-static int nbd_co_readv(BlockDriverState *bs, int64_t sector_num,
- int nb_sectors, QEMUIOVector *qiov)
+static int nbd_co_readv_1(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors, QEMUIOVector *qiov,
+ int offset)
{
BDRVNBDState *s = bs->opaque;
struct nbd_request request;
@@ -292,15 +293,16 @@ static int nbd_co_readv(BlockDriverState *bs, int64_t
sector_num,
if (nbd_co_send_request(s, &request, NULL, 0) == -1) {
reply.error = errno;
} else {
- nbd_co_receive_reply(s, &request, &reply, qiov->iov, 0);
+ nbd_co_receive_reply(s, &request, &reply, qiov->iov, offset);
}
nbd_coroutine_end(s, &request);
return -reply.error;
}
-static int nbd_co_writev(BlockDriverState *bs, int64_t sector_num,
- int nb_sectors, QEMUIOVector *qiov)
+static int nbd_co_writev_1(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors, QEMUIOVector *qiov,
+ int offset)
{
BDRVNBDState *s = bs->opaque;
struct nbd_request request;
@@ -311,7 +313,7 @@ static int nbd_co_writev(BlockDriverState *bs, int64_t
sector_num,
request.len = nb_sectors * 512;
nbd_coroutine_start(s, &request);
- if (nbd_co_send_request(s, &request, qiov->iov, 0) == -1) {
+ if (nbd_co_send_request(s, &request, qiov->iov, offset) == -1) {
reply.error = errno;
} else {
nbd_co_receive_reply(s, &request, &reply, NULL, 0);
@@ -320,6 +322,44 @@ static int nbd_co_writev(BlockDriverState *bs, int64_t
sector_num,
return -reply.error;
}
+/* qemu-nbd has a limit of slightly less than 1M per request. Try to
+ * remain aligned to 4K. */
+#define NBD_MAX_SECTORS 2040
+
+static int nbd_co_readv(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors, QEMUIOVector *qiov)
+{
+ int offset = 0;
+ int ret;
+ while (nb_sectors > NBD_MAX_SECTORS) {
+ ret = nbd_co_readv_1(bs, sector_num, NBD_MAX_SECTORS, qiov, offset);
+ if (ret < 0) {
+ return ret;
+ }
+ offset += NBD_MAX_SECTORS * 512;
+ sector_num += NBD_MAX_SECTORS;
+ nb_sectors -= NBD_MAX_SECTORS;
+ }
+ return nbd_co_readv_1(bs, sector_num, nb_sectors, qiov, offset);
+}
+
+static int nbd_co_writev(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors, QEMUIOVector *qiov)
+{
+ int offset = 0;
+ int ret;
+ while (nb_sectors > NBD_MAX_SECTORS) {
+ ret = nbd_co_writev_1(bs, sector_num, NBD_MAX_SECTORS, qiov, offset);
+ if (ret < 0) {
+ return ret;
+ }
+ offset += NBD_MAX_SECTORS * 512;
+ sector_num += NBD_MAX_SECTORS;
+ nb_sectors -= NBD_MAX_SECTORS;
+ }
+ return nbd_co_writev_1(bs, sector_num, nb_sectors, qiov, offset);
+}
+
static void nbd_close(BlockDriverState *bs)
{
BDRVNBDState *s = bs->opaque;
--
1.7.7.1
- [Qemu-devel] [PULL 00/26] nbd refactoring, fully asynchronous operation, flushing, fixes, Paolo Bonzini, 2011/12/23
- [Qemu-devel] [PATCH 01/26] add qemu_send_full and qemu_recv_full, Paolo Bonzini, 2011/12/23
- [Qemu-devel] [PATCH 02/26] sheepdog: move coroutine send/recv function to generic code, Paolo Bonzini, 2011/12/23
- [Qemu-devel] [PATCH 03/26] nbd: switch to asynchronous operation, Paolo Bonzini, 2011/12/23
- [Qemu-devel] [PATCH 04/26] nbd: split requests,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 08/26] nbd: add support for NBD_CMD_FLUSH, Paolo Bonzini, 2011/12/23
- [Qemu-devel] [PATCH 06/26] nbd: fix error handling in the server, Paolo Bonzini, 2011/12/23
- [Qemu-devel] [PATCH 05/26] nbd: allow multiple in-flight requests, Paolo Bonzini, 2011/12/23
- [Qemu-devel] [PATCH 10/26] Update ioctl order in nbd_init() to detect EBUSY, Paolo Bonzini, 2011/12/23
- [Qemu-devel] [PATCH 12/26] qemu-nbd: remove data_size argument to nbd_trip, Paolo Bonzini, 2011/12/23
- [Qemu-devel] [PATCH 13/26] move corking functions to osdep.c, Paolo Bonzini, 2011/12/23
- [Qemu-devel] [PATCH 14/26] qemu-nbd: simplify nbd_trip, Paolo Bonzini, 2011/12/23
- [Qemu-devel] [PATCH 15/26] qemu-nbd: introduce nbd_do_send_reply, Paolo Bonzini, 2011/12/23
- [Qemu-devel] [PATCH 16/26] qemu-nbd: more robust handling of invalid requests, Paolo Bonzini, 2011/12/23
- [Qemu-devel] [PATCH 19/26] qemu-nbd: introduce NBDRequest, Paolo Bonzini, 2011/12/23