diff mbox series

[RFC,ONLY,1/8] btrfs: add raid stripe tree definitions

Message ID 06a217ce02243fe88b9649d689df89eea7a570c7.1652711187.git.johannes.thumshirn@wdc.com (mailing list archive)
State New, archived
Headers show
Series btrfs: introduce raid-stripe-tree | expand

Commit Message

Johannes Thumshirn May 16, 2022, 2:31 p.m. UTC 
Add definitions for the raid-stripe-tree. This tree will hold informatioin
about the on-disk layout of the stripes in a RAID set.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 fs/btrfs/ctree.h                | 28 ++++++++++++++++++++++++++++
 include/uapi/linux/btrfs_tree.h | 17 +++++++++++++++++
 2 files changed, 45 insertions(+)

Comments

Qu Wenruo May 17, 2022, 7:39 a.m. UTC | #1 
On 2022/5/16 22:31, Johannes Thumshirn wrote:
> Add definitions for the raid-stripe-tree. This tree will hold informatioin
> about the on-disk layout of the stripes in a RAID set.
>
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> ---
>   fs/btrfs/ctree.h                | 28 ++++++++++++++++++++++++++++
>   include/uapi/linux/btrfs_tree.h | 17 +++++++++++++++++
>   2 files changed, 45 insertions(+)
>
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index 7328fb17b7f5..20aa2ebac7cd 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -1878,6 +1878,34 @@ BTRFS_SETGET_FUNCS(timespec_nsec, struct btrfs_timespec, nsec, 32);
>   BTRFS_SETGET_STACK_FUNCS(stack_timespec_sec, struct btrfs_timespec, sec, 64);
>   BTRFS_SETGET_STACK_FUNCS(stack_timespec_nsec, struct btrfs_timespec, nsec, 32);
>
> +BTRFS_SETGET_FUNCS(stripe_extent_devid, struct btrfs_stripe_extent, devid, 64);
> +BTRFS_SETGET_FUNCS(stripe_extent_offset, struct btrfs_stripe_extent, offset, 64);
> +BTRFS_SETGET_STACK_FUNCS(stack_stripe_extent_devid, struct btrfs_stripe_extent, devid, 64);
> +BTRFS_SETGET_STACK_FUNCS(stack_stripe_extent_offset, struct btrfs_stripe_extent, offset, 64);
> +
> +static inline struct btrfs_stripe_extent *btrfs_stripe_extent_nr(
> +					 struct btrfs_dp_stripe *dps, int nr)
> +{
> +	unsigned long offset = (unsigned long)dps;
> +	offset += offsetof(struct btrfs_dp_stripe, extents);
> +	offset += nr * sizeof(struct btrfs_stripe_extent);
> +	return (struct btrfs_stripe_extent *)offset;
> +}
> +
> +static inline u64 btrfs_stripe_extent_devid_nr(const struct extent_buffer *eb,
> +					       struct btrfs_dp_stripe *dps,
> +					       int nr)
> +{
> +	return btrfs_stripe_extent_devid(eb, btrfs_stripe_extent_nr(dps, nr));
> +}
> +
> +static inline u64 btrfs_stripe_extent_offset_nr(const struct extent_buffer *eb,
> +						struct btrfs_dp_stripe *dps,
> +						int nr)
> +{
> +	return btrfs_stripe_extent_offset(eb, btrfs_stripe_extent_nr(dps, nr));
> +}
> +
>   /* struct btrfs_dev_extent */
>   BTRFS_SETGET_FUNCS(dev_extent_chunk_tree, struct btrfs_dev_extent,
>   		   chunk_tree, 64);
> diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h
> index b069752a8ecf..a2d28d83cc96 100644
> --- a/include/uapi/linux/btrfs_tree.h
> +++ b/include/uapi/linux/btrfs_tree.h
> @@ -56,6 +56,9 @@
>   /* Holds the block group items for extent tree v2. */
>   #define BTRFS_BLOCK_GROUP_TREE_OBJECTID 11ULL
>
> +/* tracks RAID stripes in block groups. */
> +#define BTRFS_RAID_STRIPE_TREE_OBJECTID 12ULL
> +
>   /* device stats in the device tree */
>   #define BTRFS_DEV_STATS_OBJECTID 0ULL
>
> @@ -264,6 +267,8 @@
>    */
>   #define BTRFS_QGROUP_RELATION_KEY       246
>
> +#define BTRFS_RAID_STRIPE_KEY 247
> +
>   /*
>    * Obsolete name, see BTRFS_TEMPORARY_ITEM_KEY.
>    */
> @@ -488,6 +493,18 @@ struct btrfs_free_space_header {
>   	__le64 num_bitmaps;
>   } __attribute__ ((__packed__));
>
> +struct btrfs_stripe_extent {
> +	/* btrfs device-id this raid extent  lives on */
> +	__le64 devid;
> +	/* offset from  the devextent start */
> +	__le64 offset;

Considering we have 1G stripe length limit (at least for now), u32 may
be large enough?

Although u64 is definitely future proof.

> +} __attribute__ ((__packed__));
> +

Mind to mention the key format?

My guess is, it's (<logical bytenr>, BTRFS_RAID_STRIPE_KEY, <length>)?

Thanks,
Qu

> +struct btrfs_dp_stripe {
> +	/* array of stripe extents this stripe is comprised of */
> +	struct btrfs_stripe_extent extents;
> +} __attribute__ ((__packed__));
> +
>   #define BTRFS_HEADER_FLAG_WRITTEN	(1ULL << 0)
>   #define BTRFS_HEADER_FLAG_RELOC		(1ULL << 1)
>
Johannes Thumshirn May 17, 2022, 7:45 a.m. UTC | #2 
On 17/05/2022 09:39, Qu Wenruo wrote:
>>
>> +struct btrfs_stripe_extent {
>> +	/* btrfs device-id this raid extent  lives on */
>> +	__le64 devid;
>> +	/* offset from  the devextent start */
>> +	__le64 offset;
> 
> Considering we have 1G stripe length limit (at least for now), u32 may
> be large enough?
> 
> Although u64 is definitely future proof.
> 
>> +} __attribute__ ((__packed__));
>> +
> 
> Mind to mention the key format?
> 
> My guess is, it's (<logical bytenr>, BTRFS_RAID_STRIPE_KEY, <length>)?

Correct. I'll add a comment here.

>> +struct btrfs_dp_stripe {
>> +	/* array of stripe extents this stripe is comprised of */
>> +	struct btrfs_stripe_extent extents;
>> +} __attribute__ ((__packed__));
>> +

Another question, should I add the generation to the 
btrfs_dp_stripe? And does someone have a better name for the struct?
Qu Wenruo May 17, 2022, 7:56 a.m. UTC | #3 
On 2022/5/17 15:45, Johannes Thumshirn wrote:
> On 17/05/2022 09:39, Qu Wenruo wrote:
>>>
>>> +struct btrfs_stripe_extent {
>>> +	/* btrfs device-id this raid extent  lives on */
>>> +	__le64 devid;
>>> +	/* offset from  the devextent start */
>>> +	__le64 offset;
>>
>> Considering we have 1G stripe length limit (at least for now), u32 may
>> be large enough?
>>
>> Although u64 is definitely future proof.
>>
>>> +} __attribute__ ((__packed__));
>>> +
>>
>> Mind to mention the key format?
>>
>> My guess is, it's (<logical bytenr>, BTRFS_RAID_STRIPE_KEY, <length>)?
>
> Correct. I'll add a comment here.
>
>>> +struct btrfs_dp_stripe {
>>> +	/* array of stripe extents this stripe is comprised of */
>>> +	struct btrfs_stripe_extent extents;
>>> +} __attribute__ ((__packed__));
>>> +
>
> Another question, should I add the generation to the
> btrfs_dp_stripe? And does someone have a better name for the struct?

Why you need a new generation member?
To address the problem of possible RAID56 device mismatch?

Thanks,
Qu
diff mbox series

Patch

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 7328fb17b7f5..20aa2ebac7cd 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1878,6 +1878,34 @@  BTRFS_SETGET_FUNCS(timespec_nsec, struct btrfs_timespec, nsec, 32);
 BTRFS_SETGET_STACK_FUNCS(stack_timespec_sec, struct btrfs_timespec, sec, 64);
 BTRFS_SETGET_STACK_FUNCS(stack_timespec_nsec, struct btrfs_timespec, nsec, 32);
 
+BTRFS_SETGET_FUNCS(stripe_extent_devid, struct btrfs_stripe_extent, devid, 64);
+BTRFS_SETGET_FUNCS(stripe_extent_offset, struct btrfs_stripe_extent, offset, 64);
+BTRFS_SETGET_STACK_FUNCS(stack_stripe_extent_devid, struct btrfs_stripe_extent, devid, 64);
+BTRFS_SETGET_STACK_FUNCS(stack_stripe_extent_offset, struct btrfs_stripe_extent, offset, 64);
+
+static inline struct btrfs_stripe_extent *btrfs_stripe_extent_nr(
+					 struct btrfs_dp_stripe *dps, int nr)
+{
+	unsigned long offset = (unsigned long)dps;
+	offset += offsetof(struct btrfs_dp_stripe, extents);
+	offset += nr * sizeof(struct btrfs_stripe_extent);
+	return (struct btrfs_stripe_extent *)offset;
+}
+
+static inline u64 btrfs_stripe_extent_devid_nr(const struct extent_buffer *eb,
+					       struct btrfs_dp_stripe *dps,
+					       int nr)
+{
+	return btrfs_stripe_extent_devid(eb, btrfs_stripe_extent_nr(dps, nr));
+}
+
+static inline u64 btrfs_stripe_extent_offset_nr(const struct extent_buffer *eb,
+						struct btrfs_dp_stripe *dps,
+						int nr)
+{
+	return btrfs_stripe_extent_offset(eb, btrfs_stripe_extent_nr(dps, nr));
+}
+
 /* struct btrfs_dev_extent */
 BTRFS_SETGET_FUNCS(dev_extent_chunk_tree, struct btrfs_dev_extent,
 		   chunk_tree, 64);
diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h
index b069752a8ecf..a2d28d83cc96 100644
--- a/include/uapi/linux/btrfs_tree.h
+++ b/include/uapi/linux/btrfs_tree.h
@@ -56,6 +56,9 @@ 
 /* Holds the block group items for extent tree v2. */
 #define BTRFS_BLOCK_GROUP_TREE_OBJECTID 11ULL
 
+/* tracks RAID stripes in block groups. */
+#define BTRFS_RAID_STRIPE_TREE_OBJECTID 12ULL
+
 /* device stats in the device tree */
 #define BTRFS_DEV_STATS_OBJECTID 0ULL
 
@@ -264,6 +267,8 @@ 
  */
 #define BTRFS_QGROUP_RELATION_KEY       246
 
+#define BTRFS_RAID_STRIPE_KEY 247
+
 /*
  * Obsolete name, see BTRFS_TEMPORARY_ITEM_KEY.
  */
@@ -488,6 +493,18 @@  struct btrfs_free_space_header {
 	__le64 num_bitmaps;
 } __attribute__ ((__packed__));
 
+struct btrfs_stripe_extent {
+	/* btrfs device-id this raid extent  lives on */
+	__le64 devid;
+	/* offset from  the devextent start */
+	__le64 offset;
+} __attribute__ ((__packed__));
+
+struct btrfs_dp_stripe {
+	/* array of stripe extents this stripe is comprised of */
+	struct btrfs_stripe_extent extents;
+} __attribute__ ((__packed__));
+
 #define BTRFS_HEADER_FLAG_WRITTEN	(1ULL << 0)
 #define BTRFS_HEADER_FLAG_RELOC		(1ULL << 1)