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[Qemu-block] [PULL 12/42] nbd-server: Use a separate BlockBackend
From: |
Kevin Wolf |
Subject: |
[Qemu-block] [PULL 12/42] nbd-server: Use a separate BlockBackend |
Date: |
Mon, 5 Sep 2016 20:13:24 +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>
Reviewed-by: Max Reitz <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 1897557..80610ff 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,
uint16_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 80fbb4d..472f584 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -69,6 +69,7 @@ struct NBDExport {
AioContext *ctx;
+ BlockBackend *eject_notifier_blk;
Notifier eject_notifier;
};
@@ -807,11 +808,18 @@ 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,
uint16_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;
@@ -827,11 +835,14 @@ 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
@@ -844,6 +855,7 @@ NBDExport *nbd_export_new(BlockBackend *blk, off_t
dev_offset, off_t size,
return exp;
fail:
+ blk_unref(blk);
g_free(exp);
return NULL;
}
@@ -914,7 +926,10 @@ 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 e3571c2..99297a5 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
- [Qemu-block] [PULL 00/42] Block layer patches, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 04/42] block: Accept node-name for block-commit, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 03/42] block: Accept node-name for block-stream, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 02/42] scsi: scsi-cd without drive property for empty drive, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 07/42] block: Accept node-name for blockdev-snapshot-delete-internal-sync, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 01/42] ide: ide-cd without drive property for empty drive, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 05/42] block: Accept node-name for blockdev-backup, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 06/42] block: Accept node-name for blockdev-mirror, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 09/42] block: Accept node-name for change-backing-file, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 12/42] nbd-server: Use a separate BlockBackend,
Kevin Wolf <=
- [Qemu-block] [PULL 08/42] block: Accept node-name for blockdev-snapshot-internal-sync, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 10/42] block: Accept node-name for drive-backup, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 14/42] block: switch blk_write_compressed() to byte-based interface, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 16/42] block/io: reuse bdrv_co_pwritev() for write compressed, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 15/42] block: Convert bdrv_pwrite_compressed() to BdrvChild, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 19/42] vmdk: add vmdk_co_pwritev_compressed, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 11/42] block: Accept node-name for drive-mirror, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 13/42] nbd-server: Allow node name for nbd-server-add, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 17/42] qcow2: add qcow2_co_pwritev_compressed, Kevin Wolf, 2016/09/05
- [Qemu-block] [PULL 18/42] qcow2: cleanup qcow2_co_pwritev_compressed to avoid the recursion, Kevin Wolf, 2016/09/05