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[Qemu-devel] [PATCH v5 10/11] nbd-server: Use a separate BlockBackend
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH v5 10/11] nbd-server: Use a separate BlockBackend |
Date: |
Wed, 3 Aug 2016 13:21:33 +0200 |
The builtin NBD server uses its own BlockBackend now instead of reusing
the monitor/guest device one.
This means that it has its own writethrough setting now. The builtin
NBD server always uses writeback caching now regardless of whether the
guest device has WCE enabled. qemu-nbd respects the cache mode given on
the command line.
We still need to keep a reference to the monitor BB because we put an
eject notifier on it, but we don't use it for any I/O.
Signed-off-by: Kevin Wolf <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
---
block.c | 2 ++
blockdev-nbd.c | 4 ++--
include/block/nbd.h | 3 ++-
nbd/server.c | 25 ++++++++++++++++++++-----
qemu-nbd.c | 4 ++--
5 files changed, 28 insertions(+), 10 deletions(-)
diff --git a/block.c b/block.c
index 30d64e6..101f8c6 100644
--- a/block.c
+++ b/block.c
@@ -25,6 +25,7 @@
#include "trace.h"
#include "block/block_int.h"
#include "block/blockjob.h"
+#include "block/nbd.h"
#include "qemu/error-report.h"
#include "qemu/module.h"
#include "qapi/qmp/qerror.h"
@@ -2206,6 +2207,7 @@ static void bdrv_close(BlockDriverState *bs)
void bdrv_close_all(void)
{
block_job_cancel_sync_all();
+ nbd_export_close_all();
/* Drop references from requests still in flight, such as canceled block
* jobs whose AIO context has not been polled yet */
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index 12cae0e..c437d32 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -176,8 +176,8 @@ void qmp_nbd_server_add(const char *device, bool
has_writable, bool writable,
writable = false;
}
- exp = nbd_export_new(blk, 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY, NULL,
- errp);
+ exp = nbd_export_new(blk_bs(blk), 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY,
+ NULL, false, blk, errp);
if (!exp) {
return;
}
diff --git a/include/block/nbd.h b/include/block/nbd.h
index cb91820..ebdba0d 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -103,8 +103,9 @@ int nbd_disconnect(int fd);
typedef struct NBDExport NBDExport;
typedef struct NBDClient NBDClient;
-NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size,
+NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
uint32_t nbdflags, void (*close)(NBDExport *),
+ bool writethrough, BlockBackend *on_eject_blk,
Error **errp);
void nbd_export_close(NBDExport *exp);
void nbd_export_get(NBDExport *exp);
diff --git a/nbd/server.c b/nbd/server.c
index 29e2099..207625e 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -69,6 +69,7 @@ struct NBDExport {
AioContext *ctx;
+ BlockBackend *eject_notifier_blk;
Notifier eject_notifier;
};
@@ -809,11 +810,18 @@ static void nbd_eject_notifier(Notifier *n, void *data)
nbd_export_close(exp);
}
-NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size,
+NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
uint32_t nbdflags, void (*close)(NBDExport *),
+ bool writethrough, BlockBackend *on_eject_blk,
Error **errp)
{
+ BlockBackend *blk;
NBDExport *exp = g_malloc0(sizeof(NBDExport));
+
+ blk = blk_new();
+ blk_insert_bs(blk, bs);
+ blk_set_enable_write_cache(blk, !writethrough);
+
exp->refcount = 1;
QTAILQ_INIT(&exp->clients);
exp->blk = blk;
@@ -829,11 +837,14 @@ NBDExport *nbd_export_new(BlockBackend *blk, off_t
dev_offset, off_t size,
exp->close = close;
exp->ctx = blk_get_aio_context(blk);
- blk_ref(blk);
blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
- exp->eject_notifier.notify = nbd_eject_notifier;
- blk_add_remove_bs_notifier(blk, &exp->eject_notifier);
+ if (on_eject_blk) {
+ blk_ref(on_eject_blk);
+ exp->eject_notifier_blk = on_eject_blk;
+ exp->eject_notifier.notify = nbd_eject_notifier;
+ blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);
+ }
/*
* NBD exports are used for non-shared storage migration. Make sure
@@ -846,6 +857,7 @@ NBDExport *nbd_export_new(BlockBackend *blk, off_t
dev_offset, off_t size,
return exp;
fail:
+ blk_unref(blk);
g_free(exp);
return NULL;
}
@@ -916,7 +928,10 @@ void nbd_export_put(NBDExport *exp)
}
if (exp->blk) {
- notifier_remove(&exp->eject_notifier);
+ if (exp->eject_notifier_blk) {
+ notifier_remove(&exp->eject_notifier);
+ blk_unref(exp->eject_notifier_blk);
+ }
blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
blk_aio_detach, exp);
blk_unref(exp->blk);
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 321f02b..9e6aaa9 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -910,8 +910,8 @@ int main(int argc, char **argv)
}
}
- exp = nbd_export_new(blk, dev_offset, fd_size, nbdflags, nbd_export_closed,
- &local_err);
+ exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed,
+ writethrough, NULL, &local_err);
if (!exp) {
error_report_err(local_err);
exit(EXIT_FAILURE);
--
1.8.3.1
- Re: [Qemu-devel] [PATCH v5 05/11] block: Accept node-name for blockdev-snapshot-delete-internal-sync, (continued)
- [Qemu-devel] [PATCH v5 07/11] block: Accept node-name for change-backing-file, Kevin Wolf, 2016/08/03
- [Qemu-devel] [PATCH v5 06/11] block: Accept node-name for blockdev-snapshot-internal-sync, Kevin Wolf, 2016/08/03
- [Qemu-devel] [PATCH v5 08/11] block: Accept node-name for drive-backup, Kevin Wolf, 2016/08/03
- [Qemu-devel] [PATCH v5 09/11] block: Accept node-name for drive-mirror, Kevin Wolf, 2016/08/03
- [Qemu-devel] [PATCH v5 10/11] nbd-server: Use a separate BlockBackend,
Kevin Wolf <=
- [Qemu-devel] [PATCH v5 11/11] nbd-server: Allow node name for nbd-server-add, Kevin Wolf, 2016/08/03
- Re: [Qemu-devel] [PATCH v5 00/11] block: Accept node-name in all node level QMP commands, Kevin Wolf, 2016/08/08