From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id 20C7E94B58 for ; Thu, 11 Apr 2024 11:33:14 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 0A7621DE1C for ; Thu, 11 Apr 2024 11:33:14 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS for ; Thu, 11 Apr 2024 11:33:12 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id BDC2B44A27 for ; Thu, 11 Apr 2024 11:33:12 +0200 (CEST) From: Fiona Ebner To: pve-devel@lists.proxmox.com Date: Thu, 11 Apr 2024 11:29:23 +0200 Message-Id: <20240411092943.57377-3-f.ebner@proxmox.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240411092943.57377-1-f.ebner@proxmox.com> References: <20240411092943.57377-1-f.ebner@proxmox.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL -0.072 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Subject: [pve-devel] [PATCH qemu v3 02/22] block/copy-before-write: support unligned snapshot-discard X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Apr 2024 09:33:14 -0000 From: Vladimir Sementsov-Ogievskiy First thing that crashes on unligned access here is bdrv_reset_dirty_bitmap(). Correct way is to align-down the snapshot-discard request. Signed-off-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Fiona Ebner --- block/copy-before-write.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/block/copy-before-write.c b/block/copy-before-write.c index a2dddf6f57..0a219c2b75 100644 --- a/block/copy-before-write.c +++ b/block/copy-before-write.c @@ -325,14 +325,24 @@ static int coroutine_fn GRAPH_RDLOCK cbw_co_pdiscard_snapshot(BlockDriverState *bs, int64_t offset, int64_t bytes) { BDRVCopyBeforeWriteState *s = bs->opaque; + uint32_t cluster_size = block_copy_cluster_size(s->bcs); + int64_t aligned_offset = QEMU_ALIGN_UP(offset, cluster_size); + int64_t aligned_end = QEMU_ALIGN_DOWN(offset + bytes, cluster_size); + int64_t aligned_bytes; + + if (aligned_end <= aligned_offset) { + return 0; + } + aligned_bytes = aligned_end - aligned_offset; WITH_QEMU_LOCK_GUARD(&s->lock) { - bdrv_reset_dirty_bitmap(s->access_bitmap, offset, bytes); + bdrv_reset_dirty_bitmap(s->access_bitmap, aligned_offset, + aligned_bytes); } - block_copy_reset(s->bcs, offset, bytes); + block_copy_reset(s->bcs, aligned_offset, aligned_bytes); - return bdrv_co_pdiscard(s->target, offset, bytes); + return bdrv_co_pdiscard(s->target, aligned_offset, aligned_bytes); } static void cbw_refresh_filename(BlockDriverState *bs) -- 2.39.2