diff mbox

[v11,07/13] qmp: Add block-dirty-bitmap-enable and block-dirty-bitmap-disable

Message ID 1421080265-2228-8-git-send-email-jsnow@redhat.com
State New
Headers show

Commit Message

John Snow Jan. 12, 2015, 4:30 p.m. UTC 
From: Fam Zheng <famz@redhat.com>

This allows to put the dirty bitmap into a disabled state where no more
writes will be tracked.

It will be used before backup or writing to persistent file.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
---
 block.c               | 24 +++++++++++++++++++++++-
 blockdev.c            | 40 ++++++++++++++++++++++++++++++++++++++++
 include/block/block.h |  3 +++
 qapi/block-core.json  | 28 ++++++++++++++++++++++++++++
 qmp-commands.hx       | 10 ++++++++++
 5 files changed, 104 insertions(+), 1 deletion(-)

Comments

Max Reitz Jan. 16, 2015, 4:28 p.m. UTC | #1 
On 2015-01-12 at 11:30, John Snow wrote:
> From: Fam Zheng <famz@redhat.com>
>
> This allows to put the dirty bitmap into a disabled state where no more
> writes will be tracked.
>
> It will be used before backup or writing to persistent file.
>
> Signed-off-by: Fam Zheng <famz@redhat.com>
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>   block.c               | 24 +++++++++++++++++++++++-
>   blockdev.c            | 40 ++++++++++++++++++++++++++++++++++++++++
>   include/block/block.h |  3 +++
>   qapi/block-core.json  | 28 ++++++++++++++++++++++++++++
>   qmp-commands.hx       | 10 ++++++++++
>   5 files changed, 104 insertions(+), 1 deletion(-)
>
> diff --git a/block.c b/block.c
> index 7bf7079..bd4b449 100644
> --- a/block.c
> +++ b/block.c
> @@ -56,6 +56,7 @@ struct BdrvDirtyBitmap {
>       int64_t size;
>       int64_t granularity;
>       char *name;
> +    bool enabled;
>       QLIST_ENTRY(BdrvDirtyBitmap) list;
>   };
>   
> @@ -5373,10 +5374,16 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
>       bitmap->granularity = granularity;
>       bitmap->bitmap = hbitmap_alloc(bitmap->size, ffs(sector_granularity) - 1);
>       bitmap->name = g_strdup(name);
> +    bitmap->enabled = true;
>       QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list);
>       return bitmap;
>   }
>   
> +bool bdrv_dirty_bitmap_enabled(BdrvDirtyBitmap *bitmap)
> +{
> +    return bitmap->enabled;
> +}
> +
>   void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
>   {
>       BdrvDirtyBitmap *bm, *next;
> @@ -5391,6 +5398,16 @@ void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
>       }
>   }
>   
> +void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
> +{
> +    bitmap->enabled = false;
> +}
> +
> +void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
> +{
> +    bitmap->enabled = true;
> +}
> +
>   BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
>   {
>       BdrvDirtyBitmap *bm;
> @@ -5458,7 +5475,9 @@ void bdrv_dirty_iter_init(BlockDriverState *bs,
>   void bdrv_set_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
>                              int64_t cur_sector, int nr_sectors)
>   {
> -    hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
> +    if (bdrv_dirty_bitmap_enabled(bitmap)) {
> +        hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
> +    }

Why are you checking whether the bitmap is enabled here in 
bdrv_set_dirty_bitmap(), but neither in bdrv_reset_dirty_bitmap() nor 
bdrv_clear_dirty_bitmap()?

It seems consistent with the commit message which only states that 
disabled state means that no more writes (i.e. bdrv_set_dirty_bitmap()) 
will be tracked, but it still seems strange to me.

>   }
>   
>   void bdrv_reset_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
> @@ -5481,6 +5500,9 @@ static void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
>   {
>       BdrvDirtyBitmap *bitmap;
>       QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
> +        if (!bdrv_dirty_bitmap_enabled(bitmap)) {
> +            continue;
> +        }

Same question as above, only this time it's about bdrv_reset_dirty().

In case the answer to the question is "that's intentional":

Reviewed-by: Max Reitz <mreitz@redhat.com>
John Snow Jan. 16, 2015, 5:09 p.m. UTC | #2 
On 01/16/2015 11:28 AM, Max Reitz wrote:
> On 2015-01-12 at 11:30, John Snow wrote:
>> From: Fam Zheng <famz@redhat.com>
>>
>> This allows to put the dirty bitmap into a disabled state where no more
>> writes will be tracked.
>>
>> It will be used before backup or writing to persistent file.
>>
>> Signed-off-by: Fam Zheng <famz@redhat.com>
>> Signed-off-by: John Snow <jsnow@redhat.com>
>> ---
>>   block.c               | 24 +++++++++++++++++++++++-
>>   blockdev.c            | 40 ++++++++++++++++++++++++++++++++++++++++
>>   include/block/block.h |  3 +++
>>   qapi/block-core.json  | 28 ++++++++++++++++++++++++++++
>>   qmp-commands.hx       | 10 ++++++++++
>>   5 files changed, 104 insertions(+), 1 deletion(-)
>>
>> diff --git a/block.c b/block.c
>> index 7bf7079..bd4b449 100644
>> --- a/block.c
>> +++ b/block.c
>> @@ -56,6 +56,7 @@ struct BdrvDirtyBitmap {
>>       int64_t size;
>>       int64_t granularity;
>>       char *name;
>> +    bool enabled;
>>       QLIST_ENTRY(BdrvDirtyBitmap) list;
>>   };
>> @@ -5373,10 +5374,16 @@ BdrvDirtyBitmap
>> *bdrv_create_dirty_bitmap(BlockDriverState *bs,
>>       bitmap->granularity = granularity;
>>       bitmap->bitmap = hbitmap_alloc(bitmap->size,
>> ffs(sector_granularity) - 1);
>>       bitmap->name = g_strdup(name);
>> +    bitmap->enabled = true;
>>       QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list);
>>       return bitmap;
>>   }
>> +bool bdrv_dirty_bitmap_enabled(BdrvDirtyBitmap *bitmap)
>> +{
>> +    return bitmap->enabled;
>> +}
>> +
>>   void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap
>> *bitmap)
>>   {
>>       BdrvDirtyBitmap *bm, *next;
>> @@ -5391,6 +5398,16 @@ void bdrv_release_dirty_bitmap(BlockDriverState
>> *bs, BdrvDirtyBitmap *bitmap)
>>       }
>>   }
>> +void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
>> +{
>> +    bitmap->enabled = false;
>> +}
>> +
>> +void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
>> +{
>> +    bitmap->enabled = true;
>> +}
>> +
>>   BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
>>   {
>>       BdrvDirtyBitmap *bm;
>> @@ -5458,7 +5475,9 @@ void bdrv_dirty_iter_init(BlockDriverState *bs,
>>   void bdrv_set_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap
>> *bitmap,
>>                              int64_t cur_sector, int nr_sectors)
>>   {
>> -    hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
>> +    if (bdrv_dirty_bitmap_enabled(bitmap)) {
>> +        hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
>> +    }
>
> Why are you checking whether the bitmap is enabled here in
> bdrv_set_dirty_bitmap(), but neither in bdrv_reset_dirty_bitmap() nor
> bdrv_clear_dirty_bitmap()?
>
> It seems consistent with the commit message which only states that
> disabled state means that no more writes (i.e. bdrv_set_dirty_bitmap())
> will be tracked, but it still seems strange to me.
>
>>   }
>>   void bdrv_reset_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap
>> *bitmap,
>> @@ -5481,6 +5500,9 @@ static void bdrv_set_dirty(BlockDriverState *bs,
>> int64_t cur_sector,
>>   {
>>       BdrvDirtyBitmap *bitmap;
>>       QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
>> +        if (!bdrv_dirty_bitmap_enabled(bitmap)) {
>> +            continue;
>> +        }
>
> Same question as above, only this time it's about bdrv_reset_dirty().
>
> In case the answer to the question is "that's intentional":
>
> Reviewed-by: Max Reitz <mreitz@redhat.com>
>

Just because it's intentional doesn't make it a good idea.

Fam is currently suggesting we might just scrap the "enable/disable" and 
"frozen/normal" modes altogether in favor of a single unified status, 
but the original way he proposed enabled/disabled is that it simply, and 
exclusively enabled/disabled new writes to the bitmap -- it never was 
intended to block clears/resets.

So the bitmap is still able to be consumed while disabled, for instance.

How useful is this? Perhaps not very useful. Probably more confusing 
than useful.

I will *probably* try to unify these parameters as Fam suggested, but I 
am really eager to hear from Markus on the QMP interface side before I 
bother sending out another minor iteration.

I'll skip the R-b for now, since Fam had some ideas on how to make it nicer.

Thanks!
--js
diff mbox

Patch

diff --git a/block.c b/block.c
index 7bf7079..bd4b449 100644
--- a/block.c
+++ b/block.c
@@ -56,6 +56,7 @@  struct BdrvDirtyBitmap {
     int64_t size;
     int64_t granularity;
     char *name;
+    bool enabled;
     QLIST_ENTRY(BdrvDirtyBitmap) list;
 };
 
@@ -5373,10 +5374,16 @@  BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
     bitmap->granularity = granularity;
     bitmap->bitmap = hbitmap_alloc(bitmap->size, ffs(sector_granularity) - 1);
     bitmap->name = g_strdup(name);
+    bitmap->enabled = true;
     QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list);
     return bitmap;
 }
 
+bool bdrv_dirty_bitmap_enabled(BdrvDirtyBitmap *bitmap)
+{
+    return bitmap->enabled;
+}
+
 void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
 {
     BdrvDirtyBitmap *bm, *next;
@@ -5391,6 +5398,16 @@  void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
     }
 }
 
+void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
+{
+    bitmap->enabled = false;
+}
+
+void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
+{
+    bitmap->enabled = true;
+}
+
 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
 {
     BdrvDirtyBitmap *bm;
@@ -5458,7 +5475,9 @@  void bdrv_dirty_iter_init(BlockDriverState *bs,
 void bdrv_set_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
                            int64_t cur_sector, int nr_sectors)
 {
-    hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
+    if (bdrv_dirty_bitmap_enabled(bitmap)) {
+        hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
+    }
 }
 
 void bdrv_reset_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
@@ -5481,6 +5500,9 @@  static void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
 {
     BdrvDirtyBitmap *bitmap;
     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
+        if (!bdrv_dirty_bitmap_enabled(bitmap)) {
+            continue;
+        }
         hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
     }
 }
diff --git a/blockdev.c b/blockdev.c
index 95251c7..118cb6c 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1994,6 +1994,46 @@  void qmp_block_dirty_bitmap_remove(const char *node_ref, const char *name,
     aio_context_release(aio_context);
 }
 
+void qmp_block_dirty_bitmap_enable(const char *node_ref, const char *name,
+                                   Error **errp)
+{
+    AioContext *aio_context;
+    BdrvDirtyBitmap *bitmap;
+    BlockDriverState *bs;
+
+    bitmap = block_dirty_bitmap_lookup(node_ref, name, &bs, errp);
+    if (!bitmap) {
+        return;
+    }
+
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
+    bdrv_enable_dirty_bitmap(bitmap);
+
+    aio_context_release(aio_context);
+}
+
+void qmp_block_dirty_bitmap_disable(const char *node_ref, const char *name,
+                                    Error **errp)
+{
+    AioContext *aio_context;
+    BdrvDirtyBitmap *bitmap;
+    BlockDriverState *bs;
+
+    bitmap = block_dirty_bitmap_lookup(node_ref, name, &bs, errp);
+    if (!bitmap) {
+        return;
+    }
+
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
+    bdrv_disable_dirty_bitmap(bitmap);
+
+    aio_context_release(aio_context);
+}
+
 int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
 {
     const char *id = qdict_get_str(qdict, "id");
diff --git a/include/block/block.h b/include/block/block.h
index 66f092a..a5bc249 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -437,10 +437,13 @@  BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs,
                                         const char *name);
 void bdrv_dirty_bitmap_make_anon(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
 void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
+void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap);
+void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap);
 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs);
 uint64_t bdrv_get_default_bitmap_granularity(BlockDriverState *bs);
 uint64_t bdrv_dirty_bitmap_granularity(BlockDriverState *bs,
                                       BdrvDirtyBitmap *bitmap);
+bool bdrv_dirty_bitmap_enabled(BdrvDirtyBitmap *bitmap);
 int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t sector);
 void bdrv_set_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
                            int64_t cur_sector, int nr_sectors);
diff --git a/qapi/block-core.json b/qapi/block-core.json
index f79d165..3e863b9 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -949,6 +949,34 @@ 
   'data': 'BlockDirtyBitmap' }
 
 ##
+# @block-dirty-bitmap-enable
+#
+# Enable a dirty bitmap on the device
+#
+# Returns: nothing on success
+#          If @node-ref is not a valid block device, DeviceNotFound
+#          If @name is not found, GenericError with an explaining message
+#
+# Since 2.3
+##
+{'command': 'block-dirty-bitmap-enable',
+  'data': 'BlockDirtyBitmap' }
+
+##
+# @block-dirty-bitmap-disable
+#
+# Disable a dirty bitmap on the device
+#
+# Returns: nothing on success
+#          If @node-ref is not a valid block device, DeviceNotFound
+#          If @name is not found, GenericError with an explaining message
+#
+# Since 2.3
+##
+{'command': 'block-dirty-bitmap-disable',
+  'data': 'BlockDirtyBitmap' }
+
+##
 # @block_set_io_throttle:
 #
 # Change I/O throttle limits for a block drive.
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 4ffca8a..59be8eb 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1211,6 +1211,16 @@  EQMP
         .args_type  = "node-ref:B,name:s",
         .mhandler.cmd_new = qmp_marshal_input_block_dirty_bitmap_remove,
     },
+    {
+        .name       = "block-dirty-bitmap-enable",
+        .args_type  = "node-ref:B,name:s",
+        .mhandler.cmd_new = qmp_marshal_input_block_dirty_bitmap_enable,
+    },
+    {
+        .name       = "block-dirty-bitmap-disable",
+        .args_type  = "node-ref:B,name:s",
+        .mhandler.cmd_new = qmp_marshal_input_block_dirty_bitmap_disable,
+    },
 
 SQMP