From d106c599acad51da2d0eff0d3f87cff867d52f18 Mon Sep 17 00:00:00 2001

From: Kevin Wolf <kwolf@redhat.com>

Date: Mon, 9 Sep 2013 14:28:22 +0200

Subject: [PATCH 31/38] blockdev: Split up 'cache' option

RH-Author: Kevin Wolf <kwolf@redhat.com>

Message-id: <1378736903-18489-32-git-send-email-kwolf@redhat.com>

Patchwork-id: 54218

O-Subject: [RHEL-7.0 qemu-kvm PATCH 31/32] blockdev: Split up 'cache' option

Bugzilla: 1005818

RH-Acked-by: Fam Zheng <famz@redhat.com>

RH-Acked-by: Max Reitz <mreitz@redhat.com>

RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

Bugzilla: 1005818

The old 'cache' option really encodes three different boolean flags into

a cache mode name, without providing all combinations. Make them three

separate options instead and translate the old option to the new ones

for drive_init().

The specific boolean options take precedence if the old cache option is

specified as well, so the following options are equivalent:

-drive file=x,cache=none,cache.no-flush=true

-drive file=x,cache.writeback=true,cache.direct=true,cache.no-flush=true

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Reviewed-by: Eric Blake <eblake@redhat.com>

(cherry picked from commit 29c4e2b50d95f4a15c3dd62b39f3402f05a34907)

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

---

 blockdev.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++----------

 1 file changed, 47 insertions(+), 10 deletions(-)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 blockdev.c |   57 +++++++++++++++++++++++++++++++++++++++++++++++----------

 1 files changed, 47 insertions(+), 10 deletions(-)

diff --git a/blockdev.c b/blockdev.c

index 5d4f2f8..8ffed03 100644

--- a/blockdev.c

+++ b/blockdev.c

@@ -452,12 +452,15 @@ static DriveInfo *blockdev_init(QemuOpts *all_opts,

         }

     }

-    bdrv_flags |= BDRV_O_CACHE_WB;

-    if ((buf = qemu_opt_get(opts, "cache")) != NULL) {

-        if (bdrv_parse_cache_flags(buf, &bdrv_flags) != 0) {

-            error_report("invalid cache option");

-            return NULL;

-        }

+    bdrv_flags = 0;

+    if (qemu_opt_get_bool(opts, "cache.writeback", true)) {

+        bdrv_flags |= BDRV_O_CACHE_WB;

+    }

+    if (qemu_opt_get_bool(opts, "cache.direct", false)) {

+        bdrv_flags |= BDRV_O_NOCACHE;

+    }

+    if (qemu_opt_get_bool(opts, "cache.no-flush", true)) {

+        bdrv_flags |= BDRV_O_NO_FLUSH;

     }

 #ifdef CONFIG_LINUX_AIO

@@ -740,6 +743,8 @@ static void qemu_opt_rename(QemuOpts *opts, const char *from, const char *to)

 DriveInfo *drive_init(QemuOpts *all_opts, BlockInterfaceType block_default_type)

 {

+    const char *value;

+

     /* Change legacy command line options into QMP ones */

     qemu_opt_rename(all_opts, "iops", "throttling.iops-total");

     qemu_opt_rename(all_opts, "iops_rd", "throttling.iops-read");

@@ -751,6 +756,31 @@ DriveInfo *drive_init(QemuOpts *all_opts, BlockInterfaceType block_default_type)

     qemu_opt_rename(all_opts, "readonly", "read-only");

+    value = qemu_opt_get(all_opts, "cache");

+    if (value) {

+        int flags = 0;

+

+        if (bdrv_parse_cache_flags(value, &flags) != 0) {

+            error_report("invalid cache option");

+            return NULL;

+        }

+

+        /* Specific options take precedence */

+        if (!qemu_opt_get(all_opts, "cache.writeback")) {

+            qemu_opt_set_bool(all_opts, "cache.writeback",

+                              !!(flags & BDRV_O_CACHE_WB));

+        }

+        if (!qemu_opt_get(all_opts, "cache.direct")) {

+            qemu_opt_set_bool(all_opts, "cache.direct",

+                              !!(flags & BDRV_O_NOCACHE));

+        }

+        if (!qemu_opt_get(all_opts, "cache.no-flush")) {

+            qemu_opt_set_bool(all_opts, "cache.no-flush",

+                              !!(flags & BDRV_O_NO_FLUSH));

+        }

+        qemu_opt_unset(all_opts, "cache");

+    }

+

     return blockdev_init(all_opts, block_default_type);

 }

@@ -1674,10 +1704,17 @@ QemuOptsList qemu_common_drive_opts = {

             .type = QEMU_OPT_STRING,

             .help = "discard operation (ignore/off, unmap/on)",

         },{

-            .name = "cache",

-            .type = QEMU_OPT_STRING,

-            .help = "host cache usage (none, writeback, writethrough, "

-                    "directsync, unsafe)",

+            .name = "cache.writeback",

+            .type = QEMU_OPT_BOOL,

+            .help = "enables writeback mode for any caches",

+        },{

+            .name = "cache.direct",

+            .type = QEMU_OPT_BOOL,

+            .help = "enables use of O_DIRECT (bypass the host page cache)",

+        },{

+            .name = "cache.no-flush",

+            .type = QEMU_OPT_BOOL,

+            .help = "ignore any flush requests for the device",

         },{

             .name = "aio",

             .type = QEMU_OPT_STRING,

-- 

1.7.1