From patchwork Tue Sep 19 16:58:03 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Drobyshev X-Patchwork-Id: 13391608 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 18E52CE79AA for ; Tue, 19 Sep 2023 16:59:29 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qie3C-0003gi-Nq; Tue, 19 Sep 2023 12:58:14 -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 1qie3B-0003e5-2g; Tue, 19 Sep 2023 12:58:13 -0400 Received: from relay.virtuozzo.com ([130.117.225.111]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qie36-0002Ma-Rg; Tue, 19 Sep 2023 12:58:11 -0400 Received: from [130.117.225.1] (helo=dev005.ch-qa.vzint.dev) by relay.virtuozzo.com with esmtp (Exim 4.96) (envelope-from ) id 1qidza-00DUte-0J; Tue, 19 Sep 2023 18:57:54 +0200 To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, hreitz@redhat.com, kwolf@redhat.com, eblake@redhat.com, andrey.drobyshev@virtuozzo.com, den@virtuozzo.com Subject: [PATCH v3 7/8] qemu-img: add compression option to rebase subcommand Date: Tue, 19 Sep 2023 19:58:03 +0300 Message-Id: <20230919165804.439110-8-andrey.drobyshev@virtuozzo.com> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20230919165804.439110-1-andrey.drobyshev@virtuozzo.com> References: <20230919165804.439110-1-andrey.drobyshev@virtuozzo.com> MIME-Version: 1.0 Received-SPF: pass client-ip=130.117.225.111; envelope-from=andrey.drobyshev@virtuozzo.com; helo=relay.virtuozzo.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: , Reply-to: Andrey Drobyshev X-Patchwork-Original-From: Andrey Drobyshev via From: Andrey Drobyshev Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org If we rebase an image whose backing file has compressed clusters, we might end up wasting disk space since the copied clusters are now uncompressed. In order to have better control over this, let's add "--compress" option to the "qemu-img rebase" command. Note that this option affects only the clusters which are actually being copied from the original backing file. The clusters which were uncompressed in the target image will remain so. Signed-off-by: Andrey Drobyshev Reviewed-by: Denis V. Lunev Reviewed-by: Hanna Czenczek --- docs/tools/qemu-img.rst | 6 ++++-- qemu-img-cmds.hx | 4 ++-- qemu-img.c | 26 ++++++++++++++++++++------ 3 files changed, 26 insertions(+), 10 deletions(-) diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst index ca5a2773cf..4459c065f1 100644 --- a/docs/tools/qemu-img.rst +++ b/docs/tools/qemu-img.rst @@ -667,7 +667,7 @@ Command description: List, apply, create or delete snapshots in image *FILENAME*. -.. option:: rebase [--object OBJECTDEF] [--image-opts] [-U] [-q] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-p] [-u] -b BACKING_FILE [-F BACKING_FMT] FILENAME +.. option:: rebase [--object OBJECTDEF] [--image-opts] [-U] [-q] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-p] [-u] [-c] -b BACKING_FILE [-F BACKING_FMT] FILENAME Changes the backing file of an image. Only the formats ``qcow2`` and ``qed`` support changing the backing file. @@ -694,7 +694,9 @@ Command description: In order to achieve this, any clusters that differ between *BACKING_FILE* and the old backing file of *FILENAME* are merged - into *FILENAME* before actually changing the backing file. + into *FILENAME* before actually changing the backing file. With the + ``-c`` option specified, the clusters which are being merged (but not + the entire *FILENAME* image) are compressed when written. Note that the safe mode is an expensive operation, comparable to converting an image. It only works if the old backing file still diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx index 1b1dab5b17..068692d13e 100644 --- a/qemu-img-cmds.hx +++ b/qemu-img-cmds.hx @@ -88,9 +88,9 @@ SRST ERST DEF("rebase", img_rebase, - "rebase [--object objectdef] [--image-opts] [-U] [-q] [-f fmt] [-t cache] [-T src_cache] [-p] [-u] -b backing_file [-F backing_fmt] filename") + "rebase [--object objectdef] [--image-opts] [-U] [-q] [-f fmt] [-t cache] [-T src_cache] [-p] [-u] [-c] -b backing_file [-F backing_fmt] filename") SRST -.. option:: rebase [--object OBJECTDEF] [--image-opts] [-U] [-q] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-p] [-u] -b BACKING_FILE [-F BACKING_FMT] FILENAME +.. option:: rebase [--object OBJECTDEF] [--image-opts] [-U] [-q] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-p] [-u] [-c] -b BACKING_FILE [-F BACKING_FMT] FILENAME ERST DEF("resize", img_resize, diff --git a/qemu-img.c b/qemu-img.c index a2d6241648..9d7a4a3566 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -3527,11 +3527,13 @@ static int img_rebase(int argc, char **argv) char *filename; const char *fmt, *cache, *src_cache, *out_basefmt, *out_baseimg; int c, flags, src_flags, ret; + BdrvRequestFlags write_flags = 0; bool writethrough, src_writethrough; int unsafe = 0; bool force_share = false; int progress = 0; bool quiet = false; + bool compress = false; Error *local_err = NULL; bool image_opts = false; int64_t write_align; @@ -3548,9 +3550,10 @@ static int img_rebase(int argc, char **argv) {"object", required_argument, 0, OPTION_OBJECT}, {"image-opts", no_argument, 0, OPTION_IMAGE_OPTS}, {"force-share", no_argument, 0, 'U'}, + {"compress", no_argument, 0, 'c'}, {0, 0, 0, 0} }; - c = getopt_long(argc, argv, ":hf:F:b:upt:T:qU", + c = getopt_long(argc, argv, ":hf:F:b:upt:T:qUc", long_options, NULL); if (c == -1) { break; @@ -3598,6 +3601,9 @@ static int img_rebase(int argc, char **argv) case 'U': force_share = true; break; + case 'c': + compress = true; + break; } } @@ -3650,6 +3656,14 @@ static int img_rebase(int argc, char **argv) unfiltered_bs = bdrv_skip_filters(bs); + if (compress && !block_driver_can_compress(unfiltered_bs->drv)) { + error_report("Compression not supported for this file format"); + ret = -1; + goto out; + } else if (compress) { + write_flags |= BDRV_REQ_WRITE_COMPRESSED; + } + if (out_basefmt != NULL) { if (bdrv_find_format(out_basefmt) == NULL) { error_report("Invalid format name: '%s'", out_basefmt); @@ -3659,18 +3673,18 @@ static int img_rebase(int argc, char **argv) } /* - * We need overlay subcluster size to make sure write requests are - * aligned. + * We need overlay subcluster size (or cluster size in case writes are + * compressed) to make sure write requests are aligned. */ ret = bdrv_get_info(unfiltered_bs, &bdi); if (ret < 0) { error_report("could not get block driver info"); goto out; } else if (bdi.subcluster_size == 0) { - bdi.subcluster_size = 1; + bdi.cluster_size = bdi.subcluster_size = 1; } - write_align = bdi.subcluster_size; + write_align = compress ? bdi.cluster_size : bdi.subcluster_size; /* For safe rebasing we need to compare old and new backing file */ if (!unsafe) { @@ -3921,7 +3935,7 @@ static int img_rebase(int argc, char **argv) } else { assert(written + pnum <= IO_BUF_SIZE); ret = blk_pwrite(blk, offset + written, pnum, - buf_old + written, 0); + buf_old + written, write_flags); } if (ret < 0) { error_report("Error while writing to COW image: %s",