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Mon, 7 Sep 2020 18:20:48 +0000 (UTC) Received: from linux.fritz.box.com (ovpn-114-154.ams2.redhat.com [10.36.114.154]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9F53060BF3; Mon, 7 Sep 2020 18:20:47 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PATCH 17/29] block/export: Add blk_exp_close_all(_type) Date: Mon, 7 Sep 2020 20:19:59 +0200 Message-Id: <20200907182011.521007-18-kwolf@redhat.com> In-Reply-To: <20200907182011.521007-1-kwolf@redhat.com> References: <20200907182011.521007-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0.002 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.120; envelope-from=kwolf@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/07 02:54:37 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This adds a function to shut down all block exports, and another one to shut down the block exports of a single type. The latter is used for now when stopping the NBD server. As soon as we implement support for multiple NBD servers, we'll need a per-server list of exports and it will be replaced by a function using that. As a side effect, the BlockExport layer has a list tracking all existing exports now. closed_exports loses its only user and can go away. Signed-off-by: Kevin Wolf --- include/block/export.h | 15 ++++++++ include/block/nbd.h | 2 -- block.c | 2 +- block/export/export.c | 79 ++++++++++++++++++++++++++++++++++++++++-- blockdev-nbd.c | 2 +- nbd/server.c | 34 +++--------------- qemu-nbd.c | 2 +- 7 files changed, 100 insertions(+), 36 deletions(-) diff --git a/include/block/export.h b/include/block/export.h index cf9b1c9dad..6fffcb5651 100644 --- a/include/block/export.h +++ b/include/block/export.h @@ -15,6 +15,7 @@ #define BLOCK_EXPORT_H #include "qapi/qapi-types-block-export.h" +#include "qemu/queue.h" typedef struct BlockExport BlockExport; @@ -36,6 +37,14 @@ typedef struct BlockExportDriver { * references have been dropped. */ void (*delete)(BlockExport *); + + /* + * Start to disconnect all clients and drop other references held + * internally by the export driver. When the function returns, there may + * still be active references while the export is in the process of + * shutting down. + */ + void (*request_shutdown)(BlockExport *); } BlockExportDriver; struct BlockExport { @@ -50,10 +59,16 @@ struct BlockExport { /* The AioContext whose lock protects this BlockExport object. */ AioContext *ctx; + + /* List entry for block_exports */ + QLIST_ENTRY(BlockExport) next; }; BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp); void blk_exp_ref(BlockExport *exp); void blk_exp_unref(BlockExport *exp); +void blk_exp_request_shutdown(BlockExport *exp); +void blk_exp_close_all(void); +void blk_exp_close_all_type(BlockExportType type); #endif diff --git a/include/block/nbd.h b/include/block/nbd.h index fc2c153d5b..0b9f3e5d4e 100644 --- a/include/block/nbd.h +++ b/include/block/nbd.h @@ -337,12 +337,10 @@ int nbd_export_new(BlockExport *blk_exp, BlockDriverState *bs, 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); AioContext *nbd_export_aio_context(NBDExport *exp); NBDExport *nbd_export_find(const char *name); -void nbd_export_close_all(void); void nbd_client_new(QIOChannelSocket *sioc, QCryptoTLSCreds *tlscreds, diff --git a/block.c b/block.c index 9538af4884..acde53f92a 100644 --- a/block.c +++ b/block.c @@ -4462,7 +4462,7 @@ static void bdrv_close(BlockDriverState *bs) void bdrv_close_all(void) { assert(job_next(NULL) == NULL); - nbd_export_close_all(); + blk_exp_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/block/export/export.c b/block/export/export.c index 03ff155f97..1b36286010 100644 --- a/block/export/export.c +++ b/block/export/export.c @@ -24,6 +24,10 @@ static const BlockExportDriver *blk_exp_drivers[] = { &blk_exp_nbd, }; +/* Only accessed from the main thread */ +static QLIST_HEAD(, BlockExport) block_exports = + QLIST_HEAD_INITIALIZER(block_exports); + static const BlockExportDriver *blk_exp_find_driver(BlockExportType type) { int i; @@ -61,6 +65,7 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp) return NULL; } + QLIST_INSERT_HEAD(&block_exports, exp, next); return exp; } @@ -71,16 +76,86 @@ void blk_exp_ref(BlockExport *exp) exp->refcount++; } +/* Runs in the main thread */ +static void blk_exp_delete_bh(void *opaque) +{ + BlockExport *exp = opaque; + AioContext *aio_context = exp->ctx; + + aio_context_acquire(aio_context); + + assert(exp->refcount == 0); + QLIST_REMOVE(exp, next); + exp->drv->delete(exp); + g_free(exp); + + aio_context_release(aio_context); +} + /* Callers must hold exp->ctx lock */ void blk_exp_unref(BlockExport *exp) { assert(exp->refcount > 0); if (--exp->refcount == 0) { - exp->drv->delete(exp); - g_free(exp); + /* Touch the block_exports list only in the main thread */ + aio_bh_schedule_oneshot(qemu_get_aio_context(), blk_exp_delete_bh, + exp); } } +/* Acquires exp->ctx internally. Callers must *not* hold the lock. */ +void blk_exp_request_shutdown(BlockExport *exp) +{ + AioContext *aio_context = exp->ctx; + + aio_context_acquire(aio_context); + exp->drv->request_shutdown(exp); + aio_context_release(aio_context); +} + +/* + * Returns whether a block export of the given type exists. + * type == BLOCK_EXPORT_TYPE__MAX checks for an export of any type. + */ +static bool blk_exp_has_type(BlockExportType type) +{ + BlockExport *exp; + + if (type == BLOCK_EXPORT_TYPE__MAX) { + return !QLIST_EMPTY(&block_exports); + } + + QLIST_FOREACH(exp, &block_exports, next) { + if (exp->drv->type == type) { + return true; + } + } + + return false; +} + +/* type == BLOCK_EXPORT_TYPE__MAX for all types */ +void blk_exp_close_all_type(BlockExportType type) +{ + BlockExport *exp, *next; + + assert(in_aio_context_home_thread(qemu_get_aio_context())); + + QLIST_FOREACH_SAFE(exp, &block_exports, next, next) { + if (type != BLOCK_EXPORT_TYPE__MAX && exp->drv->type != type) { + continue; + } + blk_exp_request_shutdown(exp); + } + + AIO_WAIT_WHILE(NULL, blk_exp_has_type(type)); +} + +void blk_exp_close_all(void) +{ + blk_exp_close_all_type(BLOCK_EXPORT_TYPE__MAX); +} + void qmp_block_export_add(BlockExportOptions *export, Error **errp) { blk_exp_add(export, errp); diff --git a/blockdev-nbd.c b/blockdev-nbd.c index b34f159888..f927264777 100644 --- a/blockdev-nbd.c +++ b/blockdev-nbd.c @@ -345,7 +345,7 @@ void qmp_nbd_server_stop(Error **errp) return; } - nbd_export_close_all(); + blk_exp_close_all_type(BLOCK_EXPORT_TYPE_NBD); nbd_server_free(nbd_server); nbd_server = NULL; diff --git a/nbd/server.c b/nbd/server.c index f31d8bbb60..32147e4871 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -100,8 +100,6 @@ struct NBDExport { }; static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); -static QTAILQ_HEAD(, NBDExport) closed_exports = - QTAILQ_HEAD_INITIALIZER(closed_exports); /* NBDExportMetaContexts represents a list of contexts to be exported, * as selected by NBD_OPT_SET_META_CONTEXT. Also used for @@ -1494,12 +1492,8 @@ static void blk_aio_detach(void *opaque) static void nbd_eject_notifier(Notifier *n, void *data) { NBDExport *exp = container_of(n, NBDExport, eject_notifier); - AioContext *aio_context; - aio_context = exp->common.ctx; - aio_context_acquire(aio_context); - nbd_export_close(exp); - aio_context_release(aio_context); + blk_exp_request_shutdown(&exp->common); } void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk) @@ -1652,8 +1646,9 @@ nbd_export_aio_context(NBDExport *exp) return exp->common.ctx; } -void nbd_export_close(NBDExport *exp) +static void nbd_export_request_shutdown(BlockExport *blk_exp) { + NBDExport *exp = container_of(blk_exp, NBDExport, common); NBDClient *client, *next; blk_exp_ref(&exp->common); @@ -1672,7 +1667,6 @@ void nbd_export_close(NBDExport *exp) g_free(exp->name); exp->name = NULL; QTAILQ_REMOVE(&exports, exp, next); - QTAILQ_INSERT_TAIL(&closed_exports, exp, next); } blk_exp_unref(&exp->common); } @@ -1681,7 +1675,7 @@ void nbd_export_remove(NBDExport *exp, NbdServerRemoveMode mode, Error **errp) { ERRP_GUARD(); if (mode == NBD_SERVER_REMOVE_MODE_HARD || QTAILQ_EMPTY(&exp->clients)) { - nbd_export_close(exp); + nbd_export_request_shutdown(&exp->common); return; } @@ -1716,9 +1710,6 @@ static void nbd_export_delete(BlockExport *blk_exp) bdrv_dirty_bitmap_set_busy(exp->export_bitmap, false); g_free(exp->export_bitmap_context); } - - QTAILQ_REMOVE(&closed_exports, exp, next); - aio_wait_kick(); } const BlockExportDriver blk_exp_nbd = { @@ -1726,24 +1717,9 @@ const BlockExportDriver blk_exp_nbd = { .instance_size = sizeof(NBDExport), .create = nbd_export_create, .delete = nbd_export_delete, + .request_shutdown = nbd_export_request_shutdown, }; -void nbd_export_close_all(void) -{ - NBDExport *exp, *next; - AioContext *aio_context; - - QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { - aio_context = exp->common.ctx; - aio_context_acquire(aio_context); - nbd_export_close(exp); - aio_context_release(aio_context); - } - - AIO_WAIT_WHILE(NULL, !(QTAILQ_EMPTY(&exports) && - QTAILQ_EMPTY(&closed_exports))); -} - static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, unsigned niov, Error **errp) { diff --git a/qemu-nbd.c b/qemu-nbd.c index 23c2b7da8e..c64f83618b 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -1119,7 +1119,7 @@ int main(int argc, char **argv) do { main_loop_wait(false); if (state == TERMINATE) { - nbd_export_close_all(); + blk_exp_close_all(); state = TERMINATED; } } while (state != TERMINATED);