diff mbox series

[1/6] btrfs: add flags to give an hint to the chunk allocator

Message ID 377d6c51cb957fbad5627bb93ff0a76ce9ba79da.1639766364.git.kreijack@inwind.it (mailing list archive)
State New, archived
Headers show
Series btrfs: allocation_hint mode | expand

Commit Message

Goffredo Baroncelli Dec. 17, 2021, 6:47 p.m. UTC 
From: Goffredo Baroncelli <kreijack@inwind.it>

Add the following flags to give an hint about which chunk should be
allocated in which a disk:

- BTRFS_DEV_ALLOCATION_HINT_PREFERRED_DATA
  preferred data chunk, but metadata chunk allowed
- BTRFS_DEV_ALLOCATION_HINT_PREFERRED_METADATA
  preferred metadata chunk, but data chunk allowed
- BTRFS_DEV_ALLOCATION_HINT_METADATA_ONLY
  only metadata chunk allowed
- BTRFS_DEV_ALLOCATION_HINT_DATA_ONLY
  only data chunk allowed

Signed-off-by: Goffredo Baroncelli <kreijack@inwid.it>
---
 include/uapi/linux/btrfs_tree.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

Comments

Boris Burkov Jan. 5, 2022, 10:10 p.m. UTC | #1 
On Fri, Dec 17, 2021 at 07:47:17PM +0100, Goffredo Baroncelli wrote:
> From: Goffredo Baroncelli <kreijack@inwind.it>
> 
> Add the following flags to give an hint about which chunk should be
> allocated in which a disk:
> 
> - BTRFS_DEV_ALLOCATION_HINT_PREFERRED_DATA
>   preferred data chunk, but metadata chunk allowed
> - BTRFS_DEV_ALLOCATION_HINT_PREFERRED_METADATA
>   preferred metadata chunk, but data chunk allowed
> - BTRFS_DEV_ALLOCATION_HINT_METADATA_ONLY
>   only metadata chunk allowed
> - BTRFS_DEV_ALLOCATION_HINT_DATA_ONLY
>   only data chunk allowed

Weighing in on the naming discussion:

I think DATA_ONLY > ONLY_DATA, with my best argument for this subjective
opinion being that it follows the example of read-only.

Therefore, I think you should go with DATA_ONLY, DATA_PREFERRED,
METADATA_ONLY, METADATA_PREFERRED. Definitely put ONLY/PREFERRED on the
same side of DATA/METADATA for all four, regardless of which you choose.

Looks good otherwise.

> 
> Signed-off-by: Goffredo Baroncelli <kreijack@inwid.it>
> ---
>  include/uapi/linux/btrfs_tree.h | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h
> index 5416f1f1a77a..55da906c2eac 100644
> --- a/include/uapi/linux/btrfs_tree.h
> +++ b/include/uapi/linux/btrfs_tree.h
> @@ -386,6 +386,22 @@ struct btrfs_key {
>  	__u64 offset;
>  } __attribute__ ((__packed__));
>  
> +/* dev_item.type */
> +
> +/* btrfs chunk allocation hint */
> +#define BTRFS_DEV_ALLOCATION_HINT_BIT_COUNT	2
> +/* btrfs chunk allocation hint mask */
> +#define BTRFS_DEV_ALLOCATION_HINT_MASK	\
> +	((1 << BTRFS_DEV_ALLOCATION_HINT_BIT_COUNT) -1)
> +/* preferred data chunk, but metadata chunk allowed */
> +#define BTRFS_DEV_ALLOCATION_HINT_PREFERRED_DATA	(0ULL)
> +/* preferred metadata chunk, but data chunk allowed */
> +#define BTRFS_DEV_ALLOCATION_HINT_PREFERRED_METADATA	(1ULL)
> +/* only metadata chunk are allowed */
> +#define BTRFS_DEV_ALLOCATION_HINT_METADATA_ONLY		(2ULL)
> +/* only data chunk allowed */
> +#define BTRFS_DEV_ALLOCATION_HINT_DATA_ONLY		(3ULL)
> +
>  struct btrfs_dev_item {
>  	/* the internal btrfs device id */
>  	__le64 devid;
> -- 
> 2.34.1
>
Goffredo Baroncelli Jan. 6, 2022, 8:53 a.m. UTC | #2 
On 05/01/2022 23.10, Boris Burkov wrote:
> On Fri, Dec 17, 2021 at 07:47:17PM +0100, Goffredo Baroncelli wrote:
[...]
> 
> Therefore, I think you should go with DATA_ONLY, DATA_PREFERRED,
> METADATA_ONLY, METADATA_PREFERRED. Definitely put ONLY/PREFERRED on the
> same side of DATA/METADATA for all four, regardless of which you choose.

This was the conclusion that I already reached with Zygo. The next patches set
will rename the flag in this way.


> 
> Looks good otherwise.
> 
>>
>> Signed-off-by: Goffredo Baroncelli <kreijack@inwid.it>
>> ---
>>   include/uapi/linux/btrfs_tree.h | 16 ++++++++++++++++
>>   1 file changed, 16 insertions(+)
>>
>> diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h
>> index 5416f1f1a77a..55da906c2eac 100644
>> --- a/include/uapi/linux/btrfs_tree.h
>> +++ b/include/uapi/linux/btrfs_tree.h
>> @@ -386,6 +386,22 @@ struct btrfs_key {
>>   	__u64 offset;
>>   } __attribute__ ((__packed__));
>>   
>> +/* dev_item.type */
>> +
>> +/* btrfs chunk allocation hint */
>> +#define BTRFS_DEV_ALLOCATION_HINT_BIT_COUNT	2
>> +/* btrfs chunk allocation hint mask */
>> +#define BTRFS_DEV_ALLOCATION_HINT_MASK	\
>> +	((1 << BTRFS_DEV_ALLOCATION_HINT_BIT_COUNT) -1)
>> +/* preferred data chunk, but metadata chunk allowed */
>> +#define BTRFS_DEV_ALLOCATION_HINT_PREFERRED_DATA	(0ULL)
>> +/* preferred metadata chunk, but data chunk allowed */
>> +#define BTRFS_DEV_ALLOCATION_HINT_PREFERRED_METADATA	(1ULL)
>> +/* only metadata chunk are allowed */
>> +#define BTRFS_DEV_ALLOCATION_HINT_METADATA_ONLY		(2ULL)
>> +/* only data chunk allowed */
>> +#define BTRFS_DEV_ALLOCATION_HINT_DATA_ONLY		(3ULL)
>> +
>>   struct btrfs_dev_item {
>>   	/* the internal btrfs device id */
>>   	__le64 devid;
>> -- 
>> 2.34.1
>>
diff mbox series

Patch

diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h
index 5416f1f1a77a..55da906c2eac 100644
--- a/include/uapi/linux/btrfs_tree.h
+++ b/include/uapi/linux/btrfs_tree.h
@@ -386,6 +386,22 @@  struct btrfs_key {
 	__u64 offset;
 } __attribute__ ((__packed__));
 
+/* dev_item.type */
+
+/* btrfs chunk allocation hint */
+#define BTRFS_DEV_ALLOCATION_HINT_BIT_COUNT	2
+/* btrfs chunk allocation hint mask */
+#define BTRFS_DEV_ALLOCATION_HINT_MASK	\
+	((1 << BTRFS_DEV_ALLOCATION_HINT_BIT_COUNT) -1)
+/* preferred data chunk, but metadata chunk allowed */
+#define BTRFS_DEV_ALLOCATION_HINT_PREFERRED_DATA	(0ULL)
+/* preferred metadata chunk, but data chunk allowed */
+#define BTRFS_DEV_ALLOCATION_HINT_PREFERRED_METADATA	(1ULL)
+/* only metadata chunk are allowed */
+#define BTRFS_DEV_ALLOCATION_HINT_METADATA_ONLY		(2ULL)
+/* only data chunk allowed */
+#define BTRFS_DEV_ALLOCATION_HINT_DATA_ONLY		(3ULL)
+
 struct btrfs_dev_item {
 	/* the internal btrfs device id */
 	__le64 devid;