yeahuh / rpms / qemu-kvm

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From d106c599acad51da2d0eff0d3f87cff867d52f18 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 14:28:22 +0200
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Subject: [PATCH 31/38] blockdev: Split up 'cache' option
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RH-Author: Kevin Wolf <kwolf@redhat.com>
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Message-id: <1378736903-18489-32-git-send-email-kwolf@redhat.com>
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Patchwork-id: 54218
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O-Subject: [RHEL-7.0 qemu-kvm PATCH 31/32] blockdev: Split up 'cache' option
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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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The old 'cache' option really encodes three different boolean flags into
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a cache mode name, without providing all combinations. Make them three
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separate options instead and translate the old option to the new ones
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for drive_init().
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The specific boolean options take precedence if the old cache option is
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specified as well, so the following options are equivalent:
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-drive file=x,cache=none,cache.no-flush=true
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-drive file=x,cache.writeback=true,cache.direct=true,cache.no-flush=true
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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Reviewed-by: Eric Blake <eblake@redhat.com>
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(cherry picked from commit 29c4e2b50d95f4a15c3dd62b39f3402f05a34907)
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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---
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 blockdev.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++----------
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 1 file changed, 47 insertions(+), 10 deletions(-)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 blockdev.c |   57 +++++++++++++++++++++++++++++++++++++++++++++++----------
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 1 files changed, 47 insertions(+), 10 deletions(-)
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diff --git a/blockdev.c b/blockdev.c
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index 5d4f2f8..8ffed03 100644
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--- a/blockdev.c
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+++ b/blockdev.c
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@@ -452,12 +452,15 @@ static DriveInfo *blockdev_init(QemuOpts *all_opts,
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         }
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     }
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-    bdrv_flags |= BDRV_O_CACHE_WB;
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-    if ((buf = qemu_opt_get(opts, "cache")) != NULL) {
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-        if (bdrv_parse_cache_flags(buf, &bdrv_flags) != 0) {
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-            error_report("invalid cache option");
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-            return NULL;
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-        }
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+    bdrv_flags = 0;
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+    if (qemu_opt_get_bool(opts, "cache.writeback", true)) {
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+        bdrv_flags |= BDRV_O_CACHE_WB;
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+    }
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+    if (qemu_opt_get_bool(opts, "cache.direct", false)) {
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+        bdrv_flags |= BDRV_O_NOCACHE;
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+    }
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+    if (qemu_opt_get_bool(opts, "cache.no-flush", true)) {
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+        bdrv_flags |= BDRV_O_NO_FLUSH;
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     }
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 #ifdef CONFIG_LINUX_AIO
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@@ -740,6 +743,8 @@ static void qemu_opt_rename(QemuOpts *opts, const char *from, const char *to)
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 DriveInfo *drive_init(QemuOpts *all_opts, BlockInterfaceType block_default_type)
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 {
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+    const char *value;
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+
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     /* Change legacy command line options into QMP ones */
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     qemu_opt_rename(all_opts, "iops", "throttling.iops-total");
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     qemu_opt_rename(all_opts, "iops_rd", "throttling.iops-read");
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@@ -751,6 +756,31 @@ DriveInfo *drive_init(QemuOpts *all_opts, BlockInterfaceType block_default_type)
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     qemu_opt_rename(all_opts, "readonly", "read-only");
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+    value = qemu_opt_get(all_opts, "cache");
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+    if (value) {
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+        int flags = 0;
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+
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+        if (bdrv_parse_cache_flags(value, &flags) != 0) {
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+            error_report("invalid cache option");
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+            return NULL;
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+        }
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+
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+        /* Specific options take precedence */
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+        if (!qemu_opt_get(all_opts, "cache.writeback")) {
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+            qemu_opt_set_bool(all_opts, "cache.writeback",
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+                              !!(flags & BDRV_O_CACHE_WB));
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+        }
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+        if (!qemu_opt_get(all_opts, "cache.direct")) {
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+            qemu_opt_set_bool(all_opts, "cache.direct",
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+                              !!(flags & BDRV_O_NOCACHE));
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+        }
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+        if (!qemu_opt_get(all_opts, "cache.no-flush")) {
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+            qemu_opt_set_bool(all_opts, "cache.no-flush",
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+                              !!(flags & BDRV_O_NO_FLUSH));
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+        }
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+        qemu_opt_unset(all_opts, "cache");
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+    }
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+
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     return blockdev_init(all_opts, block_default_type);
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 }
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@@ -1674,10 +1704,17 @@ QemuOptsList qemu_common_drive_opts = {
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             .type = QEMU_OPT_STRING,
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             .help = "discard operation (ignore/off, unmap/on)",
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         },{
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-            .name = "cache",
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-            .type = QEMU_OPT_STRING,
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-            .help = "host cache usage (none, writeback, writethrough, "
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-                    "directsync, unsafe)",
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+            .name = "cache.writeback",
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+            .type = QEMU_OPT_BOOL,
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+            .help = "enables writeback mode for any caches",
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+        },{
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+            .name = "cache.direct",
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+            .type = QEMU_OPT_BOOL,
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+            .help = "enables use of O_DIRECT (bypass the host page cache)",
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+        },{
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+            .name = "cache.no-flush",
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+            .type = QEMU_OPT_BOOL,
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+            .help = "ignore any flush requests for the device",
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         },{
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             .name = "aio",
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             .type = QEMU_OPT_STRING,
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-- 
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1.7.1
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