From 2197af276d3482c1b231d7399eb501e3c61144ee Mon Sep 17 00:00:00 2001 Message-Id: <2197af276d3482c1b231d7399eb501e3c61144ee.1369658547.git.minovotn@redhat.com> In-Reply-To: <07146f8b79923c529fd93fa528e6fcbd6f571a02.1369658547.git.minovotn@redhat.com> References: <07146f8b79923c529fd93fa528e6fcbd6f571a02.1369658547.git.minovotn@redhat.com> From: Fam Zheng Date: Mon, 20 May 2013 03:36:58 +0200 Subject: [PATCH 43/47] =?UTF-8?q?vmdk:=20add=20support=20for=20=E2=80=9Czero?= =?UTF-8?q?ed=E2=80=90grain=E2=80=9D=20GTE?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Fam Zheng Message-id: <1369021022-22728-44-git-send-email-famz@redhat.com> Patchwork-id: 51479 O-Subject: [PATCH RHEL-6.5 qemu-kvm v3 43/47] vmdk: add support for “zeroed‐grain” GTE Bugzilla: 960685 RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Jeffrey Cody RH-Acked-by: Kevin Wolf Introduced support for zeroed-grain GTE, as specified in Virtual Disk Format 5.0[1]. Recent VMware hosted platform products support a new “zeroed‐grain” grain table entry (GTE). The zeroed‐grain GTE returns all zeros on read. In other words, the zeroed‐grain GTE indicates that a grain in the child disk is zero‐filled but does not actually occupy space in storage. A sparse extent with zeroed‐grain GTE has the following in its header: * SparseExtentHeader.version = 2 * SparseExtentHeader.flags has bit 2 set Other than the new flag and the possibly zeroed‐grain GTE, version 2 sparse extents are identical to version 1. Also, a zeroed‐grain GTE has value 0x1 in the GT table. [1] Virtual Disk Format 5.0, http://www.vmware.com/support/developer/vddk/vmdk_50_technote.pdf?src=vmdk Signed-off-by: Fam Zheng Signed-off-by: Stefan Hajnoczi (cherry picked from commit 14ead646fe7d5163c342ebd1e0aeb556ecf343a1) Signed-off-by: Fam Zheng --- block/vmdk.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) Signed-off-by: Michal Novotny --- block/vmdk.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/block/vmdk.c b/block/vmdk.c index c0d4c9f..3b2e9e0 100644 --- a/block/vmdk.c +++ b/block/vmdk.c @@ -33,10 +33,13 @@ #define VMDK4_MAGIC (('K' << 24) | ('D' << 16) | ('M' << 8) | 'V') #define VMDK4_COMPRESSION_DEFLATE 1 #define VMDK4_FLAG_RGD (1 << 1) +/* Zeroed-grain enable bit */ +#define VMDK4_FLAG_ZERO_GRAIN (1 << 2) #define VMDK4_FLAG_COMPRESS (1 << 16) #define VMDK4_FLAG_MARKER (1 << 17) #define VMDK4_GD_AT_END 0xffffffffffffffffULL +#define VMDK_GTE_ZEROED 0x1 /* VMDK internal error codes */ #define VMDK_OK 0 @@ -81,6 +84,8 @@ typedef struct VmdkExtent { bool flat; bool compressed; bool has_marker; + bool has_zero_grain; + int version; int64_t sectors; int64_t end_sector; int64_t flat_start_offset; @@ -567,6 +572,8 @@ static int vmdk_open_vmdk4(BlockDriverState *bs, extent->compressed = le16_to_cpu(header.compressAlgorithm) == VMDK4_COMPRESSION_DEFLATE; extent->has_marker = le32_to_cpu(header.flags) & VMDK4_FLAG_MARKER; + extent->version = le32_to_cpu(header.version); + extent->has_zero_grain = le32_to_cpu(header.flags) & VMDK4_FLAG_ZERO_GRAIN; ret = vmdk_init_tables(bs, extent); if (ret) { /* free extent allocated by vmdk_add_extent */ @@ -830,6 +837,7 @@ static int get_cluster_offset(BlockDriverState *bs, unsigned int l1_index, l2_offset, l2_index; int min_index, i, j; uint32_t min_count, *l2_table, tmp = 0; + bool zeroed = false; if (m_data) { m_data->valid = 0; @@ -885,9 +893,13 @@ static int get_cluster_offset(BlockDriverState *bs, l2_index = ((offset >> 9) / extent->cluster_sectors) % extent->l2_size; *cluster_offset = le32_to_cpu(l2_table[l2_index]); - if (!*cluster_offset) { + if (extent->has_zero_grain && *cluster_offset == VMDK_GTE_ZEROED) { + zeroed = true; + } + + if (!*cluster_offset || zeroed) { if (!allocate) { - return VMDK_UNALLOC; + return zeroed ? VMDK_ZEROED : VMDK_UNALLOC; } /* Avoid the L2 tables update for the images that have snapshots. */ @@ -958,8 +970,8 @@ static int coroutine_fn vmdk_co_is_allocated(BlockDriverState *bs, ret = get_cluster_offset(bs, extent, NULL, sector_num * 512, 0, &offset); qemu_co_mutex_unlock(&s->lock); - /* get_cluster_offset returning 0 means success */ - ret = !ret; + + ret = (ret == VMDK_OK || ret == VMDK_ZEROED); index_in_cluster = sector_num % extent->cluster_sectors; n = extent->cluster_sectors - index_in_cluster; @@ -1102,9 +1114,9 @@ static int vmdk_read(BlockDriverState *bs, int64_t sector_num, if (n > nb_sectors) { n = nb_sectors; } - if (ret) { + if (ret != VMDK_OK) { /* if not allocated, try to read from parent image, if exist */ - if (bs->backing_hd) { + if (bs->backing_hd && ret != VMDK_ZEROED) { if (!vmdk_is_cid_valid(bs)) { return -EINVAL; } -- 1.7.11.7