From 13ac133e5fbde2559899dc3717b2a2c20ce9aeb1 Mon Sep 17 00:00:00 2001
From: John Snow <jsnow@redhat.com>
Date: Wed, 27 Mar 2019 17:22:32 +0100
Subject: [PATCH 093/163] nbd: Merge nbd_export_bitmap into nbd_export_new
RH-Author: John Snow <jsnow@redhat.com>
Message-id: <20190327172308.31077-20-jsnow@redhat.com>
Patchwork-id: 85190
O-Subject: [RHEL-7.7 qemu-kvm-rhev PATCH 19/55] nbd: Merge nbd_export_bitmap into nbd_export_new
Bugzilla: 1691009
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
From: Eric Blake <eblake@redhat.com>
We only have one caller that wants to export a bitmap name,
which it does right after creation of the export. But there is
still a brief window of time where an NBD client could see the
export but not the dirty bitmap, which a robust client would
have to interpret as meaning the entire image should be treated
as dirty. Better is to eliminate the window entirely, by
inlining nbd_export_bitmap() into nbd_export_new(), and refusing
to create the bitmap in the first place if the requested bitmap
can't be located.
We also no longer need logic for setting a different bitmap
name compared to the bitmap being exported.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20190111194720.15671-8-eblake@redhat.com>
(cherry picked from commit 678ba275c77b5b12f3bc9bb369a1b824fc9f679f)
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
blockdev-nbd.c | 11 +------
include/block/nbd.h | 9 ++----
nbd/server.c | 87 ++++++++++++++++++++++++-----------------------------
qemu-nbd.c | 5 +--
4 files changed, 47 insertions(+), 65 deletions(-)
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index cd86b38..c76d541 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -175,7 +175,7 @@ void qmp_nbd_server_add(const char *device, bool has_name, const char *name,
writable = false;
}
- exp = nbd_export_new(bs, 0, -1, name, NULL,
+ exp = nbd_export_new(bs, 0, -1, name, NULL, bitmap,
writable ? 0 : NBD_FLAG_READ_ONLY,
NULL, false, on_eject_blk, errp);
if (!exp) {
@@ -186,15 +186,6 @@ void qmp_nbd_server_add(const char *device, bool has_name, const char *name,
* our only way of accessing it is through nbd_export_find(), so we can drop
* the strong reference that is @exp. */
nbd_export_put(exp);
-
- if (has_bitmap) {
- Error *err = NULL;
- nbd_export_bitmap(exp, bitmap, bitmap, &err);
- if (err) {
- error_propagate(errp, err);
- nbd_export_remove(exp, NBD_SERVER_REMOVE_MODE_HARD, NULL);
- }
- }
}
void qmp_nbd_server_remove(const char *name,
diff --git a/include/block/nbd.h b/include/block/nbd.h
index 2f9a2ae..1971b55 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -296,9 +296,9 @@ typedef struct NBDClient NBDClient;
NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
const char *name, const char *description,
- uint16_t nbdflags, void (*close)(NBDExport *),
- bool writethrough, BlockBackend *on_eject_blk,
- Error **errp);
+ const char *bitmap, uint16_t nbdflags,
+ void (*close)(NBDExport *), bool writethrough,
+ BlockBackend *on_eject_blk, Error **errp);
void nbd_export_close(NBDExport *exp);
void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp);
void nbd_export_get(NBDExport *exp);
@@ -319,9 +319,6 @@ void nbd_client_put(NBDClient *client);
void nbd_server_start(SocketAddress *addr, const char *tls_creds,
Error **errp);
-void nbd_export_bitmap(NBDExport *exp, const char *bitmap,
- const char *bitmap_export_name, Error **errp);
-
/* nbd_read
* Reads @size bytes from @ioc. Returns 0 on success.
*/
diff --git a/nbd/server.c b/nbd/server.c
index 6c02b57..6b13601 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1457,9 +1457,9 @@ static void nbd_eject_notifier(Notifier *n, void *data)
NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
const char *name, const char *description,
- uint16_t nbdflags, void (*close)(NBDExport *),
- bool writethrough, BlockBackend *on_eject_blk,
- Error **errp)
+ const char *bitmap, uint16_t nbdflags,
+ void (*close)(NBDExport *), bool writethrough,
+ BlockBackend *on_eject_blk, Error **errp)
{
AioContext *ctx;
BlockBackend *blk;
@@ -1507,6 +1507,43 @@ NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
}
exp->size -= exp->size % BDRV_SECTOR_SIZE;
+ if (bitmap) {
+ BdrvDirtyBitmap *bm = NULL;
+ BlockDriverState *bs = blk_bs(blk);
+
+ while (true) {
+ bm = bdrv_find_dirty_bitmap(bs, bitmap);
+ if (bm != NULL || bs->backing == NULL) {
+ break;
+ }
+
+ bs = bs->backing->bs;
+ }
+
+ if (bm == NULL) {
+ error_setg(errp, "Bitmap '%s' is not found", bitmap);
+ goto fail;
+ }
+
+ if ((nbdflags & NBD_FLAG_READ_ONLY) && bdrv_is_writable(bs) &&
+ bdrv_dirty_bitmap_enabled(bm)) {
+ error_setg(errp,
+ "Enabled bitmap '%s' incompatible with readonly export",
+ bitmap);
+ goto fail;
+ }
+
+ if (bdrv_dirty_bitmap_user_locked(bm)) {
+ error_setg(errp, "Bitmap '%s' is in use", bitmap);
+ goto fail;
+ }
+
+ bdrv_dirty_bitmap_set_qmp_locked(bm, true);
+ exp->export_bitmap = bm;
+ exp->export_bitmap_context = g_strdup_printf("qemu:dirty-bitmap:%s",
+ bitmap);
+ }
+
exp->close = close;
exp->ctx = blk_get_aio_context(blk);
blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
@@ -2424,47 +2461,3 @@ void nbd_client_new(QIOChannelSocket *sioc,
co = qemu_coroutine_create(nbd_co_client_start, client);
qemu_coroutine_enter(co);
}
-
-void nbd_export_bitmap(NBDExport *exp, const char *bitmap,
- const char *bitmap_export_name, Error **errp)
-{
- BdrvDirtyBitmap *bm = NULL;
- BlockDriverState *bs = blk_bs(exp->blk);
-
- if (exp->export_bitmap) {
- error_setg(errp, "Export bitmap is already set");
- return;
- }
-
- while (true) {
- bm = bdrv_find_dirty_bitmap(bs, bitmap);
- if (bm != NULL || bs->backing == NULL) {
- break;
- }
-
- bs = bs->backing->bs;
- }
-
- if (bm == NULL) {
- error_setg(errp, "Bitmap '%s' is not found", bitmap);
- return;
- }
-
- if ((exp->nbdflags & NBD_FLAG_READ_ONLY) && bdrv_is_writable(bs) &&
- bdrv_dirty_bitmap_enabled(bm)) {
- error_setg(errp,
- "Enabled bitmap '%s' incompatible with readonly export",
- bitmap);
- return;
- }
-
- if (bdrv_dirty_bitmap_user_locked(bm)) {
- error_setg(errp, "Bitmap '%s' is in use", bitmap);
- return;
- }
-
- bdrv_dirty_bitmap_set_qmp_locked(bm, true);
- exp->export_bitmap = bm;
- exp->export_bitmap_context =
- g_strdup_printf("qemu:dirty-bitmap:%s", bitmap_export_name);
-}
diff --git a/qemu-nbd.c b/qemu-nbd.c
index c85aee4..ac4c958 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -1018,8 +1018,9 @@ int main(int argc, char **argv)
}
export = nbd_export_new(bs, dev_offset, fd_size, export_name,
- export_description, nbdflags, nbd_export_closed,
- writethrough, NULL, &error_fatal);
+ export_description, NULL, nbdflags,
+ nbd_export_closed, writethrough, NULL,
+ &error_fatal);
if (device) {
#if HAVE_NBD_DEVICE
--
1.8.3.1