From patchwork Fri Apr 4 16:27:52 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: lijun X-Patchwork-Id: 337056 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id A04DD140076 for ; Sat, 5 Apr 2014 04:07:13 +1100 (EST) Received: from localhost ([::1]:51236 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WW7aA-0008FF-J2 for incoming@patchwork.ozlabs.org; Fri, 04 Apr 2014 13:07:10 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41616) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WW7Zl-0008Ev-GX for qemu-devel@nongnu.org; Fri, 04 Apr 2014 13:06:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WW7Zd-0006sz-Oo for qemu-devel@nongnu.org; Fri, 04 Apr 2014 13:06:45 -0400 Received: from [125.39.9.128] (port=23861 helo=localhost.localdomain) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WW7Zd-0006sB-3q for qemu-devel@nongnu.org; Fri, 04 Apr 2014 13:06:37 -0400 Received: from localhost.localdomain (localhost [127.0.0.1]) by localhost.localdomain (8.14.7/8.14.7) with ESMTP id s34GRu1d013739; Sat, 5 Apr 2014 00:27:56 +0800 Received: (from root@localhost) by localhost.localdomain (8.14.7/8.14.7/Submit) id s34GRsZ0013738; Sat, 5 Apr 2014 00:27:54 +0800 From: Jun Li To: kwolf@redhat.com, stefanha@redhat.com, famz@redhat.com, juli@redhat.com Date: Sat, 5 Apr 2014 00:27:52 +0800 Message-Id: <1396628872-13702-1-git-send-email-junmuzi@gmail.com> X-Mailer: git-send-email 1.8.3.1 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 125.39.9.128 Cc: Jun Li , qemu-devel@nongnu.org Subject: [Qemu-devel] [PATCH] Re: [PATCH] qcow2: Patch for shrinking qcow2 disk image X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 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 As the realization of raw shrinking, so when do qcow2 shrinking, do not check l1 entries. When resize to size1(size1 < "disk size"), the custemer knows this will destory the data. So no need to check the l1 entries which is used or not. BTW, there will possible be "disk size" > "virtual size". As this, when do qcow2 shrinking, we should to discard the unused clusters(reduce the refcount of the unused clusters, release these clusters). This is the update patch. thx. Signed-off-by: Jun Li --- block/qcow2-cluster.c | 16 +++++++++++----- block/qcow2-snapshot.c | 2 +- block/qcow2.c | 10 ++-------- block/qcow2.h | 4 ++-- 4 files changed, 16 insertions(+), 16 deletions(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 60a6910..5ccc2a4 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -29,8 +29,8 @@ #include "block/qcow2.h" #include "trace.h" -int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size, - bool exact_size) +int qcow2_truncate_l1_table(BlockDriverState *bs, uint64_t min_size, + bool exact_size) { BDRVQcowState *s = bs->opaque; int new_l1_size2, ret, i; @@ -39,7 +39,7 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size, int64_t new_l1_table_offset, new_l1_size; uint8_t data[12]; - if (min_size <= s->l1_size) + if (min_size == s->l1_size) return 0; if (exact_size) { @@ -66,7 +66,13 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size, new_l1_size2 = sizeof(uint64_t) * new_l1_size; new_l1_table = g_malloc0(align_offset(new_l1_size2, 512)); - memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t)); + + /* shrinking or growing l1 table */ + if (min_size < s->l1_size) { + memcpy(new_l1_table, s->l1_table, new_l1_size2); + } else { + memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t)); + } /* write new table (align to cluster) */ BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ALLOC_TABLE); @@ -550,7 +556,7 @@ static int get_cluster_table(BlockDriverState *bs, uint64_t offset, l1_index = offset >> (s->l2_bits + s->cluster_bits); if (l1_index >= s->l1_size) { - ret = qcow2_grow_l1_table(bs, l1_index + 1, false); + ret = qcow2_truncate_l1_table(bs, l1_index + 1, false); if (ret < 0) { return ret; } diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index 0aa9def..6ba460e 100644 --- a/block/qcow2-snapshot.c +++ b/block/qcow2-snapshot.c @@ -483,7 +483,7 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id) * L1 table of the snapshot. If the snapshot L1 table is smaller, the * current one must be padded with zeros. */ - ret = qcow2_grow_l1_table(bs, sn->l1_size, true); + ret = qcow2_truncate_l1_table(bs, sn->l1_size, true); if (ret < 0) { goto fail; } diff --git a/block/qcow2.c b/block/qcow2.c index 333e26d..4fe580e 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1858,7 +1858,7 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t offset) int64_t new_l1_size; int ret; - if (offset & 511) { + if (offset <= 0 || offset & 511) { error_report("The new size must be a multiple of 512"); return -EINVAL; } @@ -1869,14 +1869,8 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t offset) return -ENOTSUP; } - /* shrinking is currently not supported */ - if (offset < bs->total_sectors * 512) { - error_report("qcow2 doesn't support shrinking images yet"); - return -ENOTSUP; - } - new_l1_size = size_to_l1(s, offset); - ret = qcow2_grow_l1_table(bs, new_l1_size, true); + ret = qcow2_truncate_l1_table(bs, new_l1_size, true); if (ret < 0) { return ret; } diff --git a/block/qcow2.h b/block/qcow2.h index b49424b..fa36930 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -499,8 +499,8 @@ int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset, int64_t size); /* qcow2-cluster.c functions */ -int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size, - bool exact_size); +int qcow2_truncate_l1_table(BlockDriverState *bs, uint64_t min_size, + bool exact_size); int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index); void qcow2_l2_cache_reset(BlockDriverState *bs); int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);