Re: libvirt: Using rbd_create3 to create format 2 images

[Wido den Hollander <wido@42on.com>]

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On 08/30/2013 08:38 PM, Wido den Hollander wrote:
> On 08/30/2013 05:26 PM, Josh Durgin wrote:
>> On 08/30/2013 02:42 AM, Wido den Hollander wrote:
>>> Hi,
>>>
>>> I created the attached patch to have libvirt create images with format 2
>>> by default, this would simplify the CloudStack code and could also help
>>> other projects.
>>>
>>> The problem with libvirt is that there is no mechanism to supply
>>> information like order, features, stripe unit and count to the
>>> rbd_create3 method, so it's now hardcoded in libvirt.
>>>
>>> Any comments on this patch before I fire it of to the libvirt guys?
>>
>> Seems ok to me. They might want you to detect whether the function is
>> there and compile without it if librbd doesn't support it (rbd_create3
>> first appeared in bobtail).
>>
>
> Good one. Although I don't think anybody is still running Argonaut I'll
> do a version check of librbd and switch to rbd_create if needed.
>
>
What do you think of the attached patch Josh?

-- 
Wido den Hollander
42on B.V.

Phone: +31 (0)20 700 9902
Skype: contact42on

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From 68e212483a43196626413f2e487e2d6bb9c69726 Mon Sep 17 00:00:00 2001
From: Wido den Hollander <wido@widodh.nl>
Date: Fri, 30 Aug 2013 10:50:25 +0200
Subject: [PATCH] rbd: Use rbd_create3 to create RBD format 2 images by
 default

This new RBD format supports snapshotting and cloning. By having
libvirt create images in format 2 end-users of the created images
can benefit of the new RBD format.

Signed-off-by: Wido den Hollander <wido@widodh.nl>
---
 src/storage/storage_backend_rbd.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/storage/storage_backend_rbd.c b/src/storage/storage_backend_rbd.c
index d9e1789..2d4edc2 100644
--- a/src/storage/storage_backend_rbd.c
+++ b/src/storage/storage_backend_rbd.c
@@ -443,6 +443,11 @@ static int virStorageBackendRBDCreateVol(virConnectPtr conn,
     ptr.cluster = NULL;
     ptr.ioctx = NULL;
     int order = 0;
+    #if LIBRBD_VERSION_CODE > 259
+    uint64_t features = 3;
+    uint64_t stripe_count = 1;
+    uint64_t stripe_unit = 4194304;
+    #endif
     int ret = -1;
 
     VIR_DEBUG("Creating RBD image %s/%s with size %llu",
@@ -467,7 +472,12 @@ static int virStorageBackendRBDCreateVol(virConnectPtr conn,
         goto cleanup;
     }
 
+    #if LIBRBD_VERSION_CODE > 259
+    if (rbd_create3(ptr.ioctx, vol->name, vol->capacity, features, &order,
+                    stripe_count, stripe_unit) < 0) {
+    #else
     if (rbd_create(ptr.ioctx, vol->name, vol->capacity, &order) < 0) {
+    #endif
         virReportError(VIR_ERR_INTERNAL_ERROR,
                        _("failed to create volume '%s/%s'"),
                        pool->def->source.name,
-- 
1.7.9.5