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From: John Snow <jsnow@redhat.com>
To: Stefan Hajnoczi <stefanha@gmail.com>,
	Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Cc: kwolf@redhat.com, qemu-devel@nongnu.org,
	Vladimir Sementsov-Ogievskiy <vsementsov@parallels.com>,
	stefanha@redhat.com, den@openvz.org, pbonzini@redhat.com
Subject: Re: [Qemu-devel] [PATCH 4/8] block: add bdrv_load_dirty_bitmap
Date: Wed, 10 Jun 2015 18:33:17 -0400	[thread overview]
Message-ID: <5578BB2D.4010801@redhat.com> (raw)
In-Reply-To: <20150609160122.GG3181@stefanha-thinkpad.redhat.com>



On 06/09/2015 12:01 PM, Stefan Hajnoczi wrote:
> On Mon, Jun 08, 2015 at 06:21:22PM +0300, Vladimir Sementsov-Ogievskiy wrote:
>> +BdrvDirtyBitmap *bdrv_load_dirty_bitmap(BlockDriverState *bs,
>> +                                        BlockDriverState *file,
>> +                                        int granularity,
>> +                                        const char *name,
>> +                                        Error **errp)
>> +{
>> +    BlockDriver *drv = file->drv;
>> +    if (!drv) {
>> +        return NULL;
>> +    }
>> +    if (drv->bdrv_dirty_bitmap_load) {
>> +        BdrvDirtyBitmap *bitmap;
>> +        uint64_t bitmap_size = bdrv_nb_sectors(bs);
>> +        uint8_t *buf = drv->bdrv_dirty_bitmap_load(file, name, bitmap_size,
>> +                                                   granularity);
>> +        if (buf == NULL) {
>> +            return NULL;
>> +        }
>> +
>> +        bitmap = bdrv_create_dirty_bitmap(bs, granularity, name, errp);
>> +        if (bitmap == NULL) {
>> +            g_free(buf);
>> +            return NULL;
>> +        }
>> +
>> +        hbitmap_deserialize_part(bitmap->bitmap, buf, 0, bitmap_size);
>> +        hbitmap_deserialize_finish(bitmap->bitmap);
> 
> How about passing bitmap and errp into drv->bdrv_dirty_bitmap_load?
> That way bdrv_dirty_bitmap_load() can stream using
> hbitmap_deserialize_part() and does not need to allocate the full
> bitmap.  It can also report errors properly.
> 

My hunch is that this was avoided because BdrvDirtyBitmap is currently a
structure local only to block.c, but I would be fine with shifting the
header to block_int.h and giving the BdrvDirtyBitmap some limited
exposure outside of the block core file to facilitate some cleaner
function prototypes here.

OR, you could have the qcow2 layer rely on serialization functions that
are written back here in block.c that supports feeding it out
chunk-by-chunk.

Whatever happens to feel cleaner is (probably) fine by me.

--js

  reply	other threads:[~2015-06-10 22:33 UTC|newest]

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-08 15:21 [Qemu-devel] [PATCH v2 RFC 0/8] block: persistent dirty bitmaps Vladimir Sementsov-Ogievskiy
2015-06-08 15:21 ` [Qemu-devel] [PATCH 1/8] spec: add qcow2-dirty-bitmaps specification Vladimir Sementsov-Ogievskiy
2015-06-09 16:01   ` John Snow
2015-06-09 17:03   ` Stefan Hajnoczi
2015-06-10  8:19     ` Vladimir Sementsov-Ogievskiy
2015-06-10  8:49       ` Vladimir Sementsov-Ogievskiy
2015-06-10 13:00       ` Eric Blake
2015-06-11 10:16         ` Vladimir Sementsov-Ogievskiy
2015-06-10 13:24       ` Stefan Hajnoczi
2015-06-11 10:19         ` Vladimir Sementsov-Ogievskiy
2015-06-11 13:03           ` Stefan Hajnoczi
2015-06-11 16:21             ` John Snow
2015-06-12 10:28               ` Stefan Hajnoczi
2015-06-12 15:19                 ` John Snow
2015-06-10 15:34   ` Kevin Wolf
2015-06-11 10:25     ` Vladimir Sementsov-Ogievskiy
2015-06-11 16:30       ` John Snow
2015-06-12  8:33         ` Kevin Wolf
2015-08-24 10:46     ` Vladimir Sementsov-Ogievskiy
2015-08-24 13:30   ` Vladimir Sementsov-Ogievskiy
2015-08-24 14:08     ` Vladimir Sementsov-Ogievskiy
2015-08-24 14:04   ` Vladimir Sementsov-Ogievskiy
2015-08-31 22:21   ` Eric Blake
2015-08-31 22:24     ` John Snow
2015-06-08 15:21 ` [Qemu-devel] [PATCH 2/8] qcow2: add dirty-bitmaps feature Vladimir Sementsov-Ogievskiy
2015-06-09 16:52   ` Stefan Hajnoczi
2015-06-10 14:30   ` Stefan Hajnoczi
2015-06-12 19:02     ` John Snow
2015-06-15 14:42       ` Stefan Hajnoczi
2015-06-23 17:57         ` John Snow
2015-06-24  9:39           ` Stefan Hajnoczi
2015-08-14 17:14     ` Vladimir Sementsov-Ogievskiy
2015-08-26  9:09       ` Stefan Hajnoczi
2015-06-11 23:04   ` John Snow
2015-06-15 14:05     ` Vladimir Sementsov-Ogievskiy
2015-06-15 16:53       ` John Snow
2015-06-12 21:55   ` John Snow
2015-08-26 13:15     ` Vladimir Sementsov-Ogievskiy
2015-08-26 14:14       ` Vladimir Sementsov-Ogievskiy
2015-08-27 12:43   ` Vladimir Sementsov-Ogievskiy
2015-06-08 15:21 ` [Qemu-devel] [PATCH 3/8] block: store persistent dirty bitmaps Vladimir Sementsov-Ogievskiy
2015-06-08 15:21 ` [Qemu-devel] [PATCH 4/8] block: add bdrv_load_dirty_bitmap Vladimir Sementsov-Ogievskiy
2015-06-09 16:01   ` Stefan Hajnoczi
2015-06-10 22:33     ` John Snow [this message]
2015-06-11 10:41       ` Vladimir Sementsov-Ogievskiy
2015-06-08 15:21 ` [Qemu-devel] [PATCH 5/8] qcow2: add qcow2_dirty_bitmap_delete_all Vladimir Sementsov-Ogievskiy
2015-06-08 15:21 ` [Qemu-devel] [PATCH 6/8] qcow2: add autoclear bit for dirty bitmaps Vladimir Sementsov-Ogievskiy
2015-06-09 15:49   ` Stefan Hajnoczi
2015-06-09 15:50   ` Stefan Hajnoczi
2015-08-27  7:45     ` Vladimir Sementsov-Ogievskiy
2015-08-31 11:06       ` Vladimir Sementsov-Ogievskiy
2015-08-31 22:39       ` Eric Blake
2015-08-31 22:50         ` Eric Blake
2015-06-10 23:42   ` John Snow
2015-06-11  8:35     ` Kevin Wolf
2015-06-11 10:49     ` Vladimir Sementsov-Ogievskiy
2015-06-11 16:36       ` John Snow
2015-06-08 15:21 ` [Qemu-devel] [PATCH 7/8] qemu: command line option " Vladimir Sementsov-Ogievskiy
2015-06-11 20:57   ` John Snow
2015-06-12 21:49   ` John Snow
2015-06-08 15:21 ` [Qemu-devel] [PATCH 8/8] iotests: test internal persistent dirty bitmap Vladimir Sementsov-Ogievskiy
2015-06-09 16:17   ` Eric Blake
2015-06-10 15:27 ` [Qemu-devel] [PATCH v2 RFC 0/8] block: persistent dirty bitmaps Stefan Hajnoczi
2015-06-11 11:22   ` Vladimir Sementsov-Ogievskiy
2015-06-11 13:14     ` Stefan Hajnoczi
2015-06-11 20:06 ` Stefan Hajnoczi
2015-06-12  9:58   ` Denis V. Lunev
2015-06-12 10:36     ` Stefan Hajnoczi
2015-08-26  6:26       ` Vladimir Sementsov-Ogievskiy
2015-08-26  9:13         ` Stefan Hajnoczi
2015-06-12 19:34 ` John Snow
2015-06-17 14:29   ` Vladimir Sementsov-Ogievskiy
2015-06-24  0:21     ` John Snow
2015-07-08 12:24       ` Vladimir Sementsov-Ogievskiy
2015-07-08 15:21         ` John Snow
2015-08-27 10:08       ` Vladimir Sementsov-Ogievskiy

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