From patchwork Fri Mar 22 09:50:06 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fiona Ebner X-Patchwork-Id: 1914793 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=patchwork.ozlabs.org) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4V1HfK2f6fz23r9 for ; Fri, 22 Mar 2024 20:51:37 +1100 (AEDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rnbXh-0003Vz-CF; Fri, 22 Mar 2024 05:50:29 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rnbXb-0003SW-7f; Fri, 22 Mar 2024 05:50:23 -0400 Received: from proxmox-new.maurer-it.com ([94.136.29.106]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rnbXX-00020l-4T; Fri, 22 Mar 2024 05:50:22 -0400 Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id B199041987; Fri, 22 Mar 2024 10:50:14 +0100 (CET) From: Fiona Ebner To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, qemu-stable@nongnu.org, hreitz@redhat.com, kwolf@redhat.com, fam@euphon.net, stefanha@redhat.com, t.lamprecht@proxmox.com, w.bumiller@proxmox.com Subject: [PATCH v3 1/4] block/io: accept NULL qiov in bdrv_pad_request Date: Fri, 22 Mar 2024 10:50:06 +0100 Message-Id: <20240322095009.346989-2-f.ebner@proxmox.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240322095009.346989-1-f.ebner@proxmox.com> References: <20240322095009.346989-1-f.ebner@proxmox.com> MIME-Version: 1.0 Received-SPF: pass client-ip=94.136.29.106; envelope-from=f.ebner@proxmox.com; helo=proxmox-new.maurer-it.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Stefan Reiter Some operations, e.g. block-stream, perform reads while discarding the results (only copy-on-read matters). In this case, they will pass NULL as the target QEMUIOVector, which will however trip bdrv_pad_request, since it wants to extend its passed vector. In particular, this is the case for the blk_co_preadv() call in stream_populate(). If there is no qiov, no operation can be done with it, but the bytes and offset still need to be updated, so the subsequent aligned read will actually be aligned and not run into an assertion failure. In particular, this can happen when the request alignment of the top node is larger than the allocated part of the bottom node, in which case padding becomes necessary. For example: > ./qemu-img create /tmp/backing.qcow2 -f qcow2 64M -o cluster_size=32768 > ./qemu-io -c "write -P42 0x0 0x1" /tmp/backing.qcow2 > ./qemu-img create /tmp/top.qcow2 -f qcow2 64M -b /tmp/backing.qcow2 -F qcow2 > ./qemu-system-x86_64 --qmp stdio \ > --blockdev qcow2,node-name=node0,file.driver=file,file.filename=/tmp/top.qcow2 \ > < {"execute": "qmp_capabilities"} > {"execute": "blockdev-add", "arguments": { "driver": "compress", "file": "node0", "node-name": "node1" } } > {"execute": "block-stream", "arguments": { "job-id": "stream0", "device": "node1" } } > EOF Originally-by: Stefan Reiter Signed-off-by: Thomas Lamprecht [FE: do update bytes and offset in any case add reproducer to commit message] Signed-off-by: Fiona Ebner Reviewed-by: Stefan Hajnoczi --- No changes in v3. No changes in v2. block/io.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-) diff --git a/block/io.c b/block/io.c index 33150c0359..395bea3bac 100644 --- a/block/io.c +++ b/block/io.c @@ -1726,22 +1726,29 @@ static int bdrv_pad_request(BlockDriverState *bs, return 0; } - sliced_iov = qemu_iovec_slice(*qiov, *qiov_offset, *bytes, - &sliced_head, &sliced_tail, - &sliced_niov); + /* + * For prefetching in stream_populate(), no qiov is passed along, because + * only copy-on-read matters. + */ + if (qiov && *qiov) { + sliced_iov = qemu_iovec_slice(*qiov, *qiov_offset, *bytes, + &sliced_head, &sliced_tail, + &sliced_niov); - /* Guaranteed by bdrv_check_request32() */ - assert(*bytes <= SIZE_MAX); - ret = bdrv_create_padded_qiov(bs, pad, sliced_iov, sliced_niov, - sliced_head, *bytes); - if (ret < 0) { - bdrv_padding_finalize(pad); - return ret; + /* Guaranteed by bdrv_check_request32() */ + assert(*bytes <= SIZE_MAX); + ret = bdrv_create_padded_qiov(bs, pad, sliced_iov, sliced_niov, + sliced_head, *bytes); + if (ret < 0) { + bdrv_padding_finalize(pad); + return ret; + } + *qiov = &pad->local_qiov; + *qiov_offset = 0; } + *bytes += pad->head + pad->tail; *offset -= pad->head; - *qiov = &pad->local_qiov; - *qiov_offset = 0; if (padded) { *padded = true; } From patchwork Fri Mar 22 09:50:07 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fiona Ebner X-Patchwork-Id: 1914795 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=patchwork.ozlabs.org) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4V1HfW2t60z1yXy for ; Fri, 22 Mar 2024 20:51:47 +1100 (AEDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rnbXc-0003So-OZ; Fri, 22 Mar 2024 05:50:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rnbXa-0003RU-15; Fri, 22 Mar 2024 05:50:22 -0400 Received: from proxmox-new.maurer-it.com ([94.136.29.106]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rnbXW-00020k-VA; Fri, 22 Mar 2024 05:50:21 -0400 Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id B32B4419AD; Fri, 22 Mar 2024 10:50:14 +0100 (CET) From: Fiona Ebner To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, qemu-stable@nongnu.org, hreitz@redhat.com, kwolf@redhat.com, fam@euphon.net, stefanha@redhat.com, t.lamprecht@proxmox.com, w.bumiller@proxmox.com Subject: [PATCH v3 2/4] block-backend: fix edge case in bdrv_next() where BDS associated to BB changes Date: Fri, 22 Mar 2024 10:50:07 +0100 Message-Id: <20240322095009.346989-3-f.ebner@proxmox.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240322095009.346989-1-f.ebner@proxmox.com> References: <20240322095009.346989-1-f.ebner@proxmox.com> MIME-Version: 1.0 Received-SPF: pass client-ip=94.136.29.106; envelope-from=f.ebner@proxmox.com; helo=proxmox-new.maurer-it.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org The old_bs variable in bdrv_next() is currently determined by looking at the old block backend. However, if the block graph changes before the next bdrv_next() call, it might be that the associated BDS is not the same that was referenced previously. In that case, the wrong BDS is unreferenced, leading to an assertion failure later: > bdrv_unref: Assertion `bs->refcnt > 0' failed. In particular, this can happen in the context of bdrv_flush_all(), when polling for bdrv_co_flush() in the generated co-wrapper leads to a graph change (for example with a stream block job [0]). A racy reproducer: > #!/bin/bash > rm -f /tmp/backing.qcow2 > rm -f /tmp/top.qcow2 > ./qemu-img create /tmp/backing.qcow2 -f qcow2 64M > ./qemu-io -c "write -P42 0x0 0x1" /tmp/backing.qcow2 > ./qemu-img create /tmp/top.qcow2 -f qcow2 64M -b /tmp/backing.qcow2 -F qcow2 > ./qemu-system-x86_64 --qmp stdio \ > --blockdev qcow2,node-name=node0,file.driver=file,file.filename=/tmp/top.qcow2 \ > < {"execute": "qmp_capabilities"} > {"execute": "block-stream", "arguments": { "job-id": "stream0", "device": "node0" } } > {"execute": "quit"} > EOF [0]: > #0 bdrv_replace_child_tran (child=..., new_bs=..., tran=...) > #1 bdrv_replace_node_noperm (from=..., to=..., auto_skip=..., tran=..., errp=...) > #2 bdrv_replace_node_common (from=..., to=..., auto_skip=..., detach_subchain=..., errp=...) > #3 bdrv_drop_filter (bs=..., errp=...) > #4 bdrv_cor_filter_drop (cor_filter_bs=...) > #5 stream_prepare (job=...) > #6 job_prepare_locked (job=...) > #7 job_txn_apply_locked (fn=..., job=...) > #8 job_do_finalize_locked (job=...) > #9 job_exit (opaque=...) > #10 aio_bh_poll (ctx=...) > #11 aio_poll (ctx=..., blocking=...) > #12 bdrv_poll_co (s=...) > #13 bdrv_flush (bs=...) > #14 bdrv_flush_all () > #15 do_vm_stop (state=..., send_stop=...) > #16 vm_shutdown () Signed-off-by: Fiona Ebner Reviewed-by: Stefan Hajnoczi --- No changes in v3. New in v2. block/block-backend.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/block/block-backend.c b/block/block-backend.c index 9c4de79e6b..28af1eb17a 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -599,14 +599,14 @@ BlockDriverState *bdrv_next(BdrvNextIterator *it) /* Must be called from the main loop */ assert(qemu_get_current_aio_context() == qemu_get_aio_context()); + old_bs = it->bs; + /* First, return all root nodes of BlockBackends. In order to avoid * returning a BDS twice when multiple BBs refer to it, we only return it * if the BB is the first one in the parent list of the BDS. */ if (it->phase == BDRV_NEXT_BACKEND_ROOTS) { BlockBackend *old_blk = it->blk; - old_bs = old_blk ? blk_bs(old_blk) : NULL; - do { it->blk = blk_all_next(it->blk); bs = it->blk ? blk_bs(it->blk) : NULL; @@ -620,11 +620,10 @@ BlockDriverState *bdrv_next(BdrvNextIterator *it) if (bs) { bdrv_ref(bs); bdrv_unref(old_bs); + it->bs = bs; return bs; } it->phase = BDRV_NEXT_MONITOR_OWNED; - } else { - old_bs = it->bs; } /* Then return the monitor-owned BDSes without a BB attached. Ignore all From patchwork Fri Mar 22 09:50:08 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fiona Ebner X-Patchwork-Id: 1914792 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=patchwork.ozlabs.org) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4V1HfJ5TFNz1yXy for ; Fri, 22 Mar 2024 20:51:36 +1100 (AEDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rnbXb-0003T3-Ui; Fri, 22 Mar 2024 05:50:23 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rnbXZ-0003RS-T1; Fri, 22 Mar 2024 05:50:21 -0400 Received: from proxmox-new.maurer-it.com ([94.136.29.106]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rnbXW-00020j-Vy; Fri, 22 Mar 2024 05:50:21 -0400 Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 9C99241059; Fri, 22 Mar 2024 10:50:14 +0100 (CET) From: Fiona Ebner To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, qemu-stable@nongnu.org, hreitz@redhat.com, kwolf@redhat.com, fam@euphon.net, stefanha@redhat.com, t.lamprecht@proxmox.com, w.bumiller@proxmox.com Subject: [PATCH v3 3/4] block-backend: fix edge case in bdrv_next_cleanup() where BDS associated to BB changes Date: Fri, 22 Mar 2024 10:50:08 +0100 Message-Id: <20240322095009.346989-4-f.ebner@proxmox.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240322095009.346989-1-f.ebner@proxmox.com> References: <20240322095009.346989-1-f.ebner@proxmox.com> MIME-Version: 1.0 Received-SPF: pass client-ip=94.136.29.106; envelope-from=f.ebner@proxmox.com; helo=proxmox-new.maurer-it.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Same rationale as for commit "block-backend: fix edge case in bdrv_next() where BDS associated to BB changes". The block graph might change between the bdrv_next() call and the bdrv_next_cleanup() call, so it could be that the associated BDS is not the same that was referenced previously anymore. Instead, rely on bdrv_next() to set it->bs to the BDS it referenced and unreference that one in any case. Signed-off-by: Fiona Ebner Reviewed-by: Stefan Hajnoczi --- New in v3. block/block-backend.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/block/block-backend.c b/block/block-backend.c index 28af1eb17a..db6f9b92a3 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -663,13 +663,10 @@ void bdrv_next_cleanup(BdrvNextIterator *it) /* Must be called from the main loop */ assert(qemu_get_current_aio_context() == qemu_get_aio_context()); - if (it->phase == BDRV_NEXT_BACKEND_ROOTS) { - if (it->blk) { - bdrv_unref(blk_bs(it->blk)); - blk_unref(it->blk); - } - } else { - bdrv_unref(it->bs); + bdrv_unref(it->bs); + + if (it->phase == BDRV_NEXT_BACKEND_ROOTS && it->blk) { + blk_unref(it->blk); } bdrv_next_reset(it); From patchwork Fri Mar 22 09:50:09 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fiona Ebner X-Patchwork-Id: 1914796 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=patchwork.ozlabs.org) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4V1Hff3wQbz1yXy for ; Fri, 22 Mar 2024 20:51:54 +1100 (AEDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rnbXa-0003SR-UT; Fri, 22 Mar 2024 05:50:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rnbXY-0003R5-Kl; Fri, 22 Mar 2024 05:50:20 -0400 Received: from proxmox-new.maurer-it.com ([94.136.29.106]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rnbXW-00020m-Ea; Fri, 22 Mar 2024 05:50:20 -0400 Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 113C1418DD; Fri, 22 Mar 2024 10:50:15 +0100 (CET) From: Fiona Ebner To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, qemu-stable@nongnu.org, hreitz@redhat.com, kwolf@redhat.com, fam@euphon.net, stefanha@redhat.com, t.lamprecht@proxmox.com, w.bumiller@proxmox.com Subject: [PATCH v3 4/4] iotests: add test for stream job with an unaligned prefetch read Date: Fri, 22 Mar 2024 10:50:09 +0100 Message-Id: <20240322095009.346989-5-f.ebner@proxmox.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240322095009.346989-1-f.ebner@proxmox.com> References: <20240322095009.346989-1-f.ebner@proxmox.com> MIME-Version: 1.0 Received-SPF: pass client-ip=94.136.29.106; envelope-from=f.ebner@proxmox.com; helo=proxmox-new.maurer-it.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Previously, bdrv_pad_request() could not deal with a NULL qiov when a read needed to be aligned. During prefetch, a stream job will pass a NULL qiov. Add a test case to cover this scenario. By accident, also covers a previous race during shutdown, where block graph changes during iteration in bdrv_flush_all() could lead to unreferencing the wrong block driver state and an assertion failure later. Signed-off-by: Fiona Ebner Reviewed-by: Stefan Hajnoczi --- No changes in v3. New in v2. .../tests/stream-unaligned-prefetch | 86 +++++++++++++++++++ .../tests/stream-unaligned-prefetch.out | 5 ++ 2 files changed, 91 insertions(+) create mode 100755 tests/qemu-iotests/tests/stream-unaligned-prefetch create mode 100644 tests/qemu-iotests/tests/stream-unaligned-prefetch.out diff --git a/tests/qemu-iotests/tests/stream-unaligned-prefetch b/tests/qemu-iotests/tests/stream-unaligned-prefetch new file mode 100755 index 0000000000..546db1d369 --- /dev/null +++ b/tests/qemu-iotests/tests/stream-unaligned-prefetch @@ -0,0 +1,86 @@ +#!/usr/bin/env python3 +# group: rw quick +# +# Test what happens when a stream job does an unaligned prefetch read +# which requires padding while having a NULL qiov. +# +# Copyright (C) Proxmox Server Solutions GmbH +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . +# + +import os +import iotests +from iotests import imgfmt, qemu_img_create, qemu_io, QMPTestCase + +image_size = 1 * 1024 * 1024 +cluster_size = 64 * 1024 +base = os.path.join(iotests.test_dir, 'base.img') +top = os.path.join(iotests.test_dir, 'top.img') + +class TestStreamUnalignedPrefetch(QMPTestCase): + def setUp(self) -> None: + """ + Create two images: + - base image {base} with {cluster_size // 2} bytes allocated + - top image {top} without any data allocated and coarser + cluster size + + Attach a compress filter for the top image, because that + requires that the request alignment is the top image's cluster + size. + """ + qemu_img_create('-f', imgfmt, + '-o', 'cluster_size={}'.format(cluster_size // 2), + base, str(image_size)) + qemu_io('-c', f'write 0 {cluster_size // 2}', base) + qemu_img_create('-f', imgfmt, + '-o', 'cluster_size={}'.format(cluster_size), + top, str(image_size)) + + self.vm = iotests.VM() + self.vm.add_blockdev(self.vm.qmp_to_opts({ + 'driver': imgfmt, + 'node-name': 'base', + 'file': { + 'driver': 'file', + 'filename': base + } + })) + self.vm.add_blockdev(self.vm.qmp_to_opts({ + 'driver': 'compress', + 'node-name': 'compress-top', + 'file': { + 'driver': imgfmt, + 'node-name': 'top', + 'file': { + 'driver': 'file', + 'filename': top + }, + 'backing': 'base' + } + })) + self.vm.launch() + + def tearDown(self) -> None: + self.vm.shutdown() + os.remove(top) + os.remove(base) + + def test_stream_unaligned_prefetch(self) -> None: + self.vm.cmd('block-stream', job_id='stream', device='compress-top') + + +if __name__ == '__main__': + iotests.main(supported_fmts=['qcow2'], supported_protocols=['file']) diff --git a/tests/qemu-iotests/tests/stream-unaligned-prefetch.out b/tests/qemu-iotests/tests/stream-unaligned-prefetch.out new file mode 100644 index 0000000000..ae1213e6f8 --- /dev/null +++ b/tests/qemu-iotests/tests/stream-unaligned-prefetch.out @@ -0,0 +1,5 @@ +. +---------------------------------------------------------------------- +Ran 1 tests + +OK