Re: [PATCH 4/7] btrfs-progs: Introduce btrfs_raid_array and related infrastructures

[Nikolay Borisov <nborisov@suse.com>]

On  2.02.2018 10:19, Qu Wenruo wrote:
> As part of the effort to unify code and behavior between btrfs-progs and
> kernel, copy the btrfs_raid_array from kernel to btrfs-progs.
> 
> So later we can use the btrfs_raid_array[] to get needed raid info other
> than manually do if-else branches.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
>  ctree.h   | 12 +++++++++++-
>  volumes.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  volumes.h | 30 +++++++++++++++++++++++++++++
>  3 files changed, 107 insertions(+), 1 deletion(-)
> 
> diff --git a/ctree.h b/ctree.h
> index 17cdac76c58c..c76849d8deb7 100644
> --- a/ctree.h
> +++ b/ctree.h
> @@ -958,7 +958,17 @@ struct btrfs_csum_item {
>  #define BTRFS_BLOCK_GROUP_RAID5    	(1ULL << 7)
>  #define BTRFS_BLOCK_GROUP_RAID6    	(1ULL << 8)
>  #define BTRFS_BLOCK_GROUP_RESERVED	BTRFS_AVAIL_ALLOC_BIT_SINGLE
<not related to this patch but i just saw it> 

BTRFS_BLOCK_GROUP_RESERVED differs in userspace than in kernel space. 
The btrfs_Tree header has it defined as: 

#define BTRFS_BLOCK_GROUP_RESERVED      (BTRFS_AVAIL_ALLOC_BIT_SINGLE | \       
                                         BTRFS_SPACE_INFO_GLOBAL_RSV)


Otherwise LGTM: 

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

> -#define BTRFS_NR_RAID_TYPES             7
> +
> +enum btrfs_raid_types {
> +	BTRFS_RAID_RAID10,
> +	BTRFS_RAID_RAID1,
> +	BTRFS_RAID_DUP,
> +	BTRFS_RAID_RAID0,
> +	BTRFS_RAID_SINGLE,
> +	BTRFS_RAID_RAID5,
> +	BTRFS_RAID_RAID6,
> +	BTRFS_NR_RAID_TYPES
> +};
>  
>  #define BTRFS_BLOCK_GROUP_TYPE_MASK	(BTRFS_BLOCK_GROUP_DATA |    \
>  					 BTRFS_BLOCK_GROUP_SYSTEM |  \
> diff --git a/volumes.c b/volumes.c
> index a9dc8c939dc5..b47ff1f392b5 100644
> --- a/volumes.c
> +++ b/volumes.c
> @@ -30,6 +30,72 @@
>  #include "utils.h"
>  #include "kernel-lib/raid56.h"
>  
> +const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
> +	[BTRFS_RAID_RAID10] = {
> +		.sub_stripes	= 2,
> +		.dev_stripes	= 1,
> +		.devs_max	= 0,	/* 0 == as many as possible */
> +		.devs_min	= 4,
> +		.tolerated_failures = 1,
> +		.devs_increment	= 2,
> +		.ncopies	= 2,
> +	},
> +	[BTRFS_RAID_RAID1] = {
> +		.sub_stripes	= 1,
> +		.dev_stripes	= 1,
> +		.devs_max	= 2,
> +		.devs_min	= 2,
> +		.tolerated_failures = 1,
> +		.devs_increment	= 2,
> +		.ncopies	= 2,
> +	},
> +	[BTRFS_RAID_DUP] = {
> +		.sub_stripes	= 1,
> +		.dev_stripes	= 2,
> +		.devs_max	= 1,
> +		.devs_min	= 1,
> +		.tolerated_failures = 0,
> +		.devs_increment	= 1,
> +		.ncopies	= 2,
> +	},
> +	[BTRFS_RAID_RAID0] = {
> +		.sub_stripes	= 1,
> +		.dev_stripes	= 1,
> +		.devs_max	= 0,
> +		.devs_min	= 2,
> +		.tolerated_failures = 0,
> +		.devs_increment	= 1,
> +		.ncopies	= 1,
> +	},
> +	[BTRFS_RAID_SINGLE] = {
> +		.sub_stripes	= 1,
> +		.dev_stripes	= 1,
> +		.devs_max	= 1,
> +		.devs_min	= 1,
> +		.tolerated_failures = 0,
> +		.devs_increment	= 1,
> +		.ncopies	= 1,
> +	},
> +	[BTRFS_RAID_RAID5] = {
> +		.sub_stripes	= 1,
> +		.dev_stripes	= 1,
> +		.devs_max	= 0,
> +		.devs_min	= 2,
> +		.tolerated_failures = 1,
> +		.devs_increment	= 1,
> +		.ncopies	= 2,
> +	},
> +	[BTRFS_RAID_RAID6] = {
> +		.sub_stripes	= 1,
> +		.dev_stripes	= 1,
> +		.devs_max	= 0,
> +		.devs_min	= 3,
> +		.tolerated_failures = 2,
> +		.devs_increment	= 1,
> +		.ncopies	= 3,
> +	},
> +};
> +
>  struct stripe {
>  	struct btrfs_device *dev;
>  	u64 physical;
> diff --git a/volumes.h b/volumes.h
> index 7bbdf615d31a..612a0a7586f4 100644
> --- a/volumes.h
> +++ b/volumes.h
> @@ -108,6 +108,36 @@ struct map_lookup {
>  	struct btrfs_bio_stripe stripes[];
>  };
>  
> +struct btrfs_raid_attr {
> +	int sub_stripes;	/* sub_stripes info for map */
> +	int dev_stripes;	/* stripes per dev */
> +	int devs_max;		/* max devs to use */
> +	int devs_min;		/* min devs needed */
> +	int tolerated_failures; /* max tolerated fail devs */
> +	int devs_increment;	/* ndevs has to be a multiple of this */
> +	int ncopies;		/* how many copies to data has */
> +};
> +
> +extern const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES];
> +
> +static inline enum btrfs_raid_types btrfs_bg_flags_to_raid_index(u64 flags)
> +{
> +	if (flags & BTRFS_BLOCK_GROUP_RAID10)
> +		return BTRFS_RAID_RAID10;
> +	else if (flags & BTRFS_BLOCK_GROUP_RAID1)
> +		return BTRFS_RAID_RAID1;
> +	else if (flags & BTRFS_BLOCK_GROUP_DUP)
> +		return BTRFS_RAID_DUP;
> +	else if (flags & BTRFS_BLOCK_GROUP_RAID0)
> +		return BTRFS_RAID_RAID0;
> +	else if (flags & BTRFS_BLOCK_GROUP_RAID5)
> +		return BTRFS_RAID_RAID5;
> +	else if (flags & BTRFS_BLOCK_GROUP_RAID6)
> +		return BTRFS_RAID_RAID6;
> +
> +	return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
> +}
> +
>  #define btrfs_multi_bio_size(n) (sizeof(struct btrfs_multi_bio) + \
>  			    (sizeof(struct btrfs_bio_stripe) * (n)))
>  #define btrfs_map_lookup_size(n) (sizeof(struct map_lookup) + \
>