From patchwork Thu Aug 13 16:29:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 276593 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7E013C433E1 for ; Thu, 13 Aug 2020 16:36:21 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3BC2E206A4 for ; Thu, 13 Aug 2020 16:36:21 +0000 (UTC) Authentication-Results: mail.kernel.org; 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Thu, 13 Aug 2020 16:29:55 +0000 (UTC) Received: from linux.fritz.box.com (ovpn-113-97.ams2.redhat.com [10.36.113.97]) by smtp.corp.redhat.com (Postfix) with ESMTP id 38E7B5C1A3; Thu, 13 Aug 2020 16:29:54 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Subject: [RFC PATCH 06/22] qemu-nbd: Use raw block driver for --offset Date: Thu, 13 Aug 2020 18:29:19 +0200 Message-Id: <20200813162935.210070-7-kwolf@redhat.com> In-Reply-To: <20200813162935.210070-1-kwolf@redhat.com> References: <20200813162935.210070-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0.001 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.81; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/13 02:03:30 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-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=-1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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" Instead of implementing qemu-nbd --offset in the NBD code, just put a raw block node with the requested offset on top of the user image and rely on that doing the job. This does not only simplify the nbd_export_new() interface and bring it closer to the set of options that the nbd-server-add QMP command offers, but in fact it also eliminates a potential source for bugs in the NBD code which previously had to add the offset manually in all relevant places. Signed-off-by: Kevin Wolf --- include/block/nbd.h | 4 ++-- blockdev-nbd.c | 9 +-------- nbd/server.c | 34 +++++++++++++++++----------------- qemu-nbd.c | 27 ++++++++++++--------------- 4 files changed, 32 insertions(+), 42 deletions(-) diff --git a/include/block/nbd.h b/include/block/nbd.h index c8c5cb6b61..3846d2bac8 100644 --- a/include/block/nbd.h +++ b/include/block/nbd.h @@ -329,8 +329,8 @@ typedef struct NBDExport NBDExport; typedef struct NBDClient NBDClient; BlockExport *nbd_export_create(BlockExportOptions *exp_args, Error **errp); -NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset, - uint64_t size, const char *name, const char *desc, +NBDExport *nbd_export_new(BlockDriverState *bs, + const char *name, const char *desc, const char *bitmap, bool readonly, bool shared, void (*close)(NBDExport *), bool writethrough, BlockBackend *on_eject_blk, Error **errp); diff --git a/blockdev-nbd.c b/blockdev-nbd.c index a1dc11bdd7..16cda3b052 100644 --- a/blockdev-nbd.c +++ b/blockdev-nbd.c @@ -154,7 +154,6 @@ BlockExport *nbd_export_create(BlockExportOptions *exp_args, Error **errp) BlockDriverState *bs = NULL; BlockBackend *on_eject_blk; NBDExport *exp = NULL; - int64_t len; AioContext *aio_context; assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD); @@ -192,12 +191,6 @@ BlockExport *nbd_export_create(BlockExportOptions *exp_args, Error **errp) aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); - len = bdrv_getlength(bs); - if (len < 0) { - error_setg_errno(errp, -len, - "Failed to determine the NBD export's length"); - goto out; - } if (!arg->has_writable) { arg->writable = false; @@ -206,7 +199,7 @@ BlockExport *nbd_export_create(BlockExportOptions *exp_args, Error **errp) arg->writable = false; } - exp = nbd_export_new(bs, 0, len, arg->name, arg->description, arg->bitmap, + exp = nbd_export_new(bs, arg->name, arg->description, arg->bitmap, !arg->writable, !arg->writable, NULL, false, on_eject_blk, errp); if (!exp) { diff --git a/nbd/server.c b/nbd/server.c index 774325dbe5..92360d1f08 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -89,7 +89,6 @@ struct NBDExport { BlockBackend *blk; char *name; char *description; - uint64_t dev_offset; uint64_t size; uint16_t nbdflags; QTAILQ_HEAD(, NBDClient) clients; @@ -1507,8 +1506,8 @@ static void nbd_eject_notifier(Notifier *n, void *data) aio_context_release(aio_context); } -NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset, - uint64_t size, const char *name, const char *desc, +NBDExport *nbd_export_new(BlockDriverState *bs, + const char *name, const char *desc, const char *bitmap, bool readonly, bool shared, void (*close)(NBDExport *), bool writethrough, BlockBackend *on_eject_blk, Error **errp) @@ -1516,9 +1515,17 @@ NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset, AioContext *ctx; BlockBackend *blk; NBDExport *exp; + int64_t size; uint64_t perm; int ret; + size = bdrv_getlength(bs); + if (size < 0) { + error_setg_errno(errp, -size, + "Failed to determine the NBD export's length"); + return NULL; + } + exp = g_new0(NBDExport, 1); exp->common = (BlockExport) { .drv = &blk_exp_nbd, @@ -1553,8 +1560,6 @@ NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset, exp->refcount = 1; QTAILQ_INIT(&exp->clients); exp->blk = blk; - assert(dev_offset <= INT64_MAX); - exp->dev_offset = dev_offset; exp->name = g_strdup(name); assert(!desc || strlen(desc) <= NBD_MAX_STRING_SIZE); exp->description = g_strdup(desc); @@ -1569,7 +1574,7 @@ NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset, exp->nbdflags |= (NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES | NBD_FLAG_SEND_FAST_ZERO); } - assert(size <= INT64_MAX - dev_offset); + assert(size <= INT64_MAX); exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); if (bitmap) { @@ -1928,8 +1933,7 @@ static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, stl_be_p(&chunk.length, pnum); ret = nbd_co_send_iov(client, iov, 1, errp); } else { - ret = blk_pread(exp->blk, offset + progress + exp->dev_offset, - data + progress, pnum); + ret = blk_pread(exp->blk, offset + progress, data + progress, pnum); if (ret < 0) { error_setg_errno(errp, -ret, "reading from file failed"); break; @@ -2303,8 +2307,7 @@ static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, data, request->len, errp); } - ret = blk_pread(exp->blk, request->from + exp->dev_offset, data, - request->len); + ret = blk_pread(exp->blk, request->from, data, request->len); if (ret < 0) { return nbd_send_generic_reply(client, request->handle, ret, "reading from file failed", errp); @@ -2339,7 +2342,7 @@ static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request, assert(request->type == NBD_CMD_CACHE); - ret = blk_co_preadv(exp->blk, request->from + exp->dev_offset, request->len, + ret = blk_co_preadv(exp->blk, request->from, request->len, NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH); return nbd_send_generic_reply(client, request->handle, ret, @@ -2370,8 +2373,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client, if (request->flags & NBD_CMD_FLAG_FUA) { flags |= BDRV_REQ_FUA; } - ret = blk_pwrite(exp->blk, request->from + exp->dev_offset, - data, request->len, flags); + ret = blk_pwrite(exp->blk, request->from, data, request->len, flags); return nbd_send_generic_reply(client, request->handle, ret, "writing to file failed", errp); @@ -2386,8 +2388,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client, if (request->flags & NBD_CMD_FLAG_FAST_ZERO) { flags |= BDRV_REQ_NO_FALLBACK; } - ret = blk_pwrite_zeroes(exp->blk, request->from + exp->dev_offset, - request->len, flags); + ret = blk_pwrite_zeroes(exp->blk, request->from, request->len, flags); return nbd_send_generic_reply(client, request->handle, ret, "writing to file failed", errp); @@ -2401,8 +2402,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client, "flush failed", errp); case NBD_CMD_TRIM: - ret = blk_co_pdiscard(exp->blk, request->from + exp->dev_offset, - request->len); + ret = blk_co_pdiscard(exp->blk, request->from, request->len); if (ret == 0 && request->flags & NBD_CMD_FLAG_FUA) { ret = blk_co_flush(exp->blk); } diff --git a/qemu-nbd.c b/qemu-nbd.c index d2657b8db5..818c3f5d46 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -523,7 +523,6 @@ int main(int argc, char **argv) const char *port = NULL; char *sockpath = NULL; char *device = NULL; - int64_t fd_size; QemuOpts *sn_opts = NULL; const char *sn_id_or_name = NULL; const char *sopt = "hVb:o:p:rsnc:dvk:e:f:tl:x:T:D:B:L"; @@ -1028,6 +1027,17 @@ int main(int argc, char **argv) } bs = blk_bs(blk); + if (dev_offset) { + QDict *raw_opts = qdict_new(); + qdict_put_str(raw_opts, "driver", "raw"); + qdict_put_str(raw_opts, "file", bs->node_name); + qdict_put_int(raw_opts, "offset", dev_offset); + bs = bdrv_open(NULL, NULL, raw_opts, flags, &error_fatal); + blk_remove_bs(blk); + blk_insert_bs(blk, bs, &error_fatal); + bdrv_unref(bs); + } + blk_set_enable_write_cache(blk, !writethrough); if (sn_opts) { @@ -1045,21 +1055,8 @@ int main(int argc, char **argv) } bs->detect_zeroes = detect_zeroes; - fd_size = blk_getlength(blk); - if (fd_size < 0) { - error_report("Failed to determine the image length: %s", - strerror(-fd_size)); - exit(EXIT_FAILURE); - } - - if (dev_offset >= fd_size) { - error_report("Offset (%" PRIu64 ") has to be smaller than the image " - "size (%" PRId64 ")", dev_offset, fd_size); - exit(EXIT_FAILURE); - } - fd_size -= dev_offset; - export = nbd_export_new(bs, dev_offset, fd_size, export_name, + export = nbd_export_new(bs, export_name, export_description, bitmap, readonly, shared > 1, nbd_export_closed, writethrough, NULL, &error_fatal);