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[PATCH v2 16/31] block/export: Allocate BlockExport in blk_exp_add()
From: |
Kevin Wolf |
Subject: |
[PATCH v2 16/31] block/export: Allocate BlockExport in blk_exp_add() |
Date: |
Thu, 24 Sep 2020 17:27:02 +0200 |
Instead of letting the driver allocate and return the BlockExport
object, allocate it already in blk_exp_add() and pass it. This allows us
to initialise the generic part before calling into the driver so that
the driver can just use these values instead of having to parse the
options a second time.
For symmetry, move freeing the BlockExport to blk_exp_unref().
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
include/block/export.h | 8 +++++++-
include/block/nbd.h | 11 ++++++-----
block/export/export.c | 18 +++++++++++++++++-
blockdev-nbd.c | 26 ++++++++++++++------------
nbd/server.c | 30 +++++++++++++-----------------
5 files changed, 57 insertions(+), 36 deletions(-)
diff --git a/include/block/export.h b/include/block/export.h
index e6f96f4e1e..cf9b1c9dad 100644
--- a/include/block/export.h
+++ b/include/block/export.h
@@ -22,8 +22,14 @@ typedef struct BlockExportDriver {
/* The export type that this driver services */
BlockExportType type;
+ /*
+ * The size of the driver-specific state that contains BlockExport as its
+ * first field.
+ */
+ size_t instance_size;
+
/* Creates and starts a new block export */
- BlockExport *(*create)(BlockExportOptions *, Error **);
+ int (*create)(BlockExport *, BlockExportOptions *, Error **);
/*
* Frees a removed block export. This function is only called after all
diff --git a/include/block/nbd.h b/include/block/nbd.h
index e3bd112227..fc2c153d5b 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -330,11 +330,12 @@ int nbd_errno_to_system_errno(int err);
typedef struct NBDExport NBDExport;
typedef struct NBDClient NBDClient;
-BlockExport *nbd_export_create(BlockExportOptions *exp_args, Error **errp);
-NBDExport *nbd_export_new(BlockDriverState *bs,
- const char *name, const char *desc,
- const char *bitmap, bool readonly, bool shared,
- bool writethrough, Error **errp);
+int nbd_export_create(BlockExport *exp, BlockExportOptions *exp_args,
+ Error **errp);
+int nbd_export_new(BlockExport *blk_exp, BlockDriverState *bs,
+ const char *name, const char *desc,
+ const char *bitmap, bool readonly, bool shared,
+ bool writethrough, Error **errp);
void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk);
void nbd_export_close(NBDExport *exp);
void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp);
diff --git a/block/export/export.c b/block/export/export.c
index 8635318ef1..6b2b29078b 100644
--- a/block/export/export.c
+++ b/block/export/export.c
@@ -39,6 +39,8 @@ static const BlockExportDriver
*blk_exp_find_driver(BlockExportType type)
BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp)
{
const BlockExportDriver *drv;
+ BlockExport *exp;
+ int ret;
drv = blk_exp_find_driver(export->type);
if (!drv) {
@@ -46,7 +48,20 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error
**errp)
return NULL;
}
- return drv->create(export, errp);
+ assert(drv->instance_size >= sizeof(BlockExport));
+ exp = g_malloc0(drv->instance_size);
+ *exp = (BlockExport) {
+ .drv = drv,
+ .refcount = 1,
+ };
+
+ ret = drv->create(exp, export, errp);
+ if (ret < 0) {
+ g_free(exp);
+ return NULL;
+ }
+
+ return exp;
}
/* Callers must hold exp->ctx lock */
@@ -62,6 +77,7 @@ void blk_exp_unref(BlockExport *exp)
assert(exp->refcount > 0);
if (--exp->refcount == 0) {
exp->drv->delete(exp);
+ g_free(exp);
}
}
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index ef14303b25..b34f159888 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -173,18 +173,19 @@ void qmp_nbd_server_start(SocketAddressLegacy *addr,
qapi_free_SocketAddress(addr_flat);
}
-BlockExport *nbd_export_create(BlockExportOptions *exp_args, Error **errp)
+int nbd_export_create(BlockExport *exp, BlockExportOptions *exp_args,
+ Error **errp)
{
BlockExportOptionsNbd *arg = &exp_args->u.nbd;
BlockDriverState *bs = NULL;
- NBDExport *exp = NULL;
AioContext *aio_context;
+ int ret;
assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD);
if (!nbd_server && !is_qemu_nbd) {
error_setg(errp, "NBD server not running");
- return NULL;
+ return -EINVAL;
}
if (!arg->has_name) {
@@ -193,22 +194,22 @@ BlockExport *nbd_export_create(BlockExportOptions
*exp_args, Error **errp)
if (strlen(arg->name) > NBD_MAX_STRING_SIZE) {
error_setg(errp, "export name '%s' too long", arg->name);
- return NULL;
+ return -EINVAL;
}
if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) {
error_setg(errp, "description '%s' too long", arg->description);
- return NULL;
+ return -EINVAL;
}
if (nbd_export_find(arg->name)) {
error_setg(errp, "NBD server already has export named '%s'",
arg->name);
- return NULL;
+ return -EEXIST;
}
bs = bdrv_lookup_bs(NULL, exp_args->node_name, errp);
if (!bs) {
- return NULL;
+ return -ENOENT;
}
aio_context = bdrv_get_aio_context(bs);
@@ -218,6 +219,7 @@ BlockExport *nbd_export_create(BlockExportOptions
*exp_args, Error **errp)
arg->writable = false;
}
if (bdrv_is_read_only(bs) && arg->writable) {
+ ret = -EINVAL;
error_setg(errp, "Cannot export read-only node as writable");
goto out;
}
@@ -226,22 +228,22 @@ BlockExport *nbd_export_create(BlockExportOptions
*exp_args, Error **errp)
exp_args->writethrough = false;
}
- exp = nbd_export_new(bs, arg->name, arg->description, arg->bitmap,
+ ret = nbd_export_new(exp, bs, arg->name, arg->description, arg->bitmap,
!arg->writable, !arg->writable,
exp_args->writethrough, errp);
- if (!exp) {
+ if (ret < 0) {
goto out;
}
/* The list of named exports has a strong reference to this export now and
* our only way of accessing it is through nbd_export_find(), so we can
drop
* the strong reference that is @exp. */
- blk_exp_unref((BlockExport*) exp);
+ blk_exp_unref(exp);
+ ret = 0;
out:
aio_context_release(aio_context);
- /* TODO Remove the cast: nbd_export_new() will return a BlockExport. */
- return (BlockExport*) exp;
+ return ret;
}
void qmp_nbd_server_add(NbdServerAddOptions *arg, Error **errp)
diff --git a/nbd/server.c b/nbd/server.c
index 7cf81646fc..f31d8bbb60 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1514,14 +1514,14 @@ void nbd_export_set_on_eject_blk(BlockExport *exp,
BlockBackend *blk)
blk_add_remove_bs_notifier(blk, &nbd_exp->eject_notifier);
}
-NBDExport *nbd_export_new(BlockDriverState *bs,
- const char *name, const char *desc,
- const char *bitmap, bool readonly, bool shared,
- bool writethrough, Error **errp)
+int nbd_export_new(BlockExport *blk_exp, BlockDriverState *bs,
+ const char *name, const char *desc,
+ const char *bitmap, bool readonly, bool shared,
+ bool writethrough, Error **errp)
{
+ NBDExport *exp = container_of(blk_exp, NBDExport, common);
AioContext *ctx;
BlockBackend *blk;
- NBDExport *exp;
int64_t size;
uint64_t perm;
int ret;
@@ -1530,17 +1530,11 @@ NBDExport *nbd_export_new(BlockDriverState *bs,
if (size < 0) {
error_setg_errno(errp, -size,
"Failed to determine the NBD export's length");
- return NULL;
+ return size;
}
ctx = bdrv_get_aio_context(bs);
-
- exp = g_new0(NBDExport, 1);
- exp->common = (BlockExport) {
- .drv = &blk_exp_nbd,
- .refcount = 1,
- .ctx = ctx,
- };
+ blk_exp->ctx = ctx;
/*
* NBD exports are used for non-shared storage migration. Make sure
@@ -1599,16 +1593,19 @@ NBDExport *nbd_export_new(BlockDriverState *bs,
}
if (bm == NULL) {
+ ret = -ENOENT;
error_setg(errp, "Bitmap '%s' is not found", bitmap);
goto fail;
}
if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) {
+ ret = -EINVAL;
goto fail;
}
if (readonly && bdrv_is_writable(bs) &&
bdrv_dirty_bitmap_enabled(bm)) {
+ ret = -EINVAL;
error_setg(errp,
"Enabled bitmap '%s' incompatible with readonly export",
bitmap);
@@ -1628,14 +1625,13 @@ NBDExport *nbd_export_new(BlockDriverState *bs,
blk_exp_ref(&exp->common);
QTAILQ_INSERT_TAIL(&exports, exp, next);
- return exp;
+ return 0;
fail:
blk_unref(blk);
g_free(exp->name);
g_free(exp->description);
- g_free(exp);
- return NULL;
+ return ret;
}
NBDExport *nbd_export_find(const char *name)
@@ -1722,12 +1718,12 @@ static void nbd_export_delete(BlockExport *blk_exp)
}
QTAILQ_REMOVE(&closed_exports, exp, next);
- g_free(exp);
aio_wait_kick();
}
const BlockExportDriver blk_exp_nbd = {
.type = BLOCK_EXPORT_TYPE_NBD,
+ .instance_size = sizeof(NBDExport),
.create = nbd_export_create,
.delete = nbd_export_delete,
};
--
2.25.4
- [PATCH v2 03/31] qapi: Rename BlockExport to BlockExportOptions, (continued)
- [PATCH v2 03/31] qapi: Rename BlockExport to BlockExportOptions, Kevin Wolf, 2020/09/24
- [PATCH v2 08/31] nbd: Add max-connections to nbd-server-start, Kevin Wolf, 2020/09/24
- [PATCH v2 09/31] nbd: Add writethrough to block-export-add, Kevin Wolf, 2020/09/24
- [PATCH v2 04/31] block/export: Add BlockExport infrastructure and block-export-add, Kevin Wolf, 2020/09/24
- [PATCH v2 06/31] qemu-nbd: Use raw block driver for --offset, Kevin Wolf, 2020/09/24
- [PATCH v2 05/31] qemu-storage-daemon: Use qmp_block_export_add(), Kevin Wolf, 2020/09/24
- [PATCH v2 07/31] block/export: Remove magic from block-export-add, Kevin Wolf, 2020/09/24
- [PATCH v2 10/31] nbd: Remove NBDExport.close callback, Kevin Wolf, 2020/09/24
- [PATCH v2 11/31] qemu-nbd: Use blk_exp_add() to create the export, Kevin Wolf, 2020/09/24
- [PATCH v2 14/31] block/export: Move AioContext from NBDExport to BlockExport, Kevin Wolf, 2020/09/24
- [PATCH v2 16/31] block/export: Allocate BlockExport in blk_exp_add(),
Kevin Wolf <=
- [PATCH v2 12/31] nbd/server: Simplify export shutdown, Kevin Wolf, 2020/09/24
- [PATCH v2 13/31] block/export: Move refcount from NBDExport to BlockExport, Kevin Wolf, 2020/09/24
- [PATCH v2 19/31] block/export: Move strong user reference to block_exports, Kevin Wolf, 2020/09/24
- [PATCH v2 15/31] block/export: Add node-name to BlockExportOptions, Kevin Wolf, 2020/09/24
- [PATCH v2 17/31] block/export: Add blk_exp_close_all(_type), Kevin Wolf, 2020/09/24
- [PATCH v2 20/31] block/export: Add block-export-del, Kevin Wolf, 2020/09/24
- [PATCH v2 22/31] block/export: Move blk to BlockExport, Kevin Wolf, 2020/09/24
- [PATCH v2 21/31] block/export: Add BLOCK_EXPORT_DELETED event, Kevin Wolf, 2020/09/24
- [PATCH v2 18/31] block/export: Add 'id' option to block-export-add, Kevin Wolf, 2020/09/24