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From 789d0334d894eaea6a5ca35538926bbb63a9cea3 Mon Sep 17 00:00:00 2001
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From: Kevin Wolf <kwolf@redhat.com>
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Date: Mon, 9 Sep 2013 14:28:01 +0200
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Subject: [PATCH 10/38] qcow2: Options to enable discard for freed clusters
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RH-Author: Kevin Wolf <kwolf@redhat.com>
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Message-id: <1378736903-18489-11-git-send-email-kwolf@redhat.com>
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Patchwork-id: 54195
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O-Subject: [RHEL-7.0 qemu-kvm PATCH 10/32] qcow2: Options to enable discard for freed clusters
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Bugzilla: 1005818
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RH-Acked-by: Fam Zheng <famz@redhat.com>
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RH-Acked-by: Max Reitz <mreitz@redhat.com>
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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Bugzilla: 1005818
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Deleted snapshots are discarded in the image file by default, discard
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requests take their default from the -drive discard=... option and other
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places that free clusters must always be enabled explicitly.
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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(cherry picked from commit 67af674e478054086f972811dd0a11289afa39a9)
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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---
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block/qcow2-refcount.c | 5 +++++
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block/qcow2.c | 26 ++++++++++++++++++++++++++
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block/qcow2.h | 5 +++++
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3 files changed, 36 insertions(+)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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block/qcow2-refcount.c | 5 +++++
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block/qcow2.c | 26 ++++++++++++++++++++++++++
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block/qcow2.h | 5 +++++
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3 files changed, 36 insertions(+), 0 deletions(-)
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diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
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index 6d35e49..7488988 100644
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--- a/block/qcow2-refcount.c
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+++ b/block/qcow2-refcount.c
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@@ -488,6 +488,11 @@ static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs,
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s->free_cluster_index = cluster_index;
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}
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refcount_block[block_index] = cpu_to_be16(refcount);
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+ if (refcount == 0 && s->discard_passthrough[type]) {
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+ /* Try discarding, ignore errors */
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+ /* FIXME Doing this cluster by cluster will be painfully slow */
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+ bdrv_discard(bs->file, cluster_offset, 1);
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+ }
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}
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ret = 0;
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diff --git a/block/qcow2.c b/block/qcow2.c
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index e28ea47..ef8a2ca 100644
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--- a/block/qcow2.c
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+++ b/block/qcow2.c
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@@ -295,6 +295,22 @@ static QemuOptsList qcow2_runtime_opts = {
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.type = QEMU_OPT_BOOL,
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.help = "Postpone refcount updates",
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},
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+ {
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+ .name = QCOW2_OPT_DISCARD_REQUEST,
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+ .type = QEMU_OPT_BOOL,
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+ .help = "Pass guest discard requests to the layer below",
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+ },
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+ {
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+ .name = QCOW2_OPT_DISCARD_SNAPSHOT,
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+ .type = QEMU_OPT_BOOL,
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+ .help = "Generate discard requests when snapshot related space "
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+ "is freed",
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+ },
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+ {
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+ .name = QCOW2_OPT_DISCARD_OTHER,
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+ .type = QEMU_OPT_BOOL,
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+ .help = "Generate discard requests when other clusters are freed",
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+ },
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{ /* end of list */ }
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},
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};
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@@ -532,6 +548,16 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags)
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s->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS,
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(s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS));
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+ s->discard_passthrough[QCOW2_DISCARD_NEVER] = false;
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+ s->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true;
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+ s->discard_passthrough[QCOW2_DISCARD_REQUEST] =
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+ qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST,
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+ flags & BDRV_O_UNMAP);
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+ s->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] =
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+ qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true);
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+ s->discard_passthrough[QCOW2_DISCARD_OTHER] =
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+ qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false);
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+
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qemu_opts_del(opts);
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if (s->use_lazy_refcounts && s->qcow_version < 3) {
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diff --git a/block/qcow2.h b/block/qcow2.h
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index 64a6479..6f91b9a 100644
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--- a/block/qcow2.h
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+++ b/block/qcow2.h
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@@ -60,6 +60,9 @@
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#define QCOW2_OPT_LAZY_REFCOUNTS "lazy_refcounts"
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+#define QCOW2_OPT_DISCARD_REQUEST "pass_discard_request"
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+#define QCOW2_OPT_DISCARD_SNAPSHOT "pass_discard_snapshot"
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+#define QCOW2_OPT_DISCARD_OTHER "pass_discard_other"
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typedef struct QCowHeader {
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uint32_t magic;
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@@ -187,6 +190,8 @@ typedef struct BDRVQcowState {
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int qcow_version;
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bool use_lazy_refcounts;
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+ bool discard_passthrough[QCOW2_DISCARD_MAX];
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+
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uint64_t incompatible_features;
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uint64_t compatible_features;
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uint64_t autoclear_features;
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--
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1.7.1
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