As general comment, good to hear that something is moving around raid5/6 + write hole and multiple mirroring.
However I am guessing if this is time to simplify the RAID code. There are a lot of "if" which could be avoided using
the values stored in the array "btrfs_raid_array[]".
Below some comments:
On 07/13/2018 08:46 PM, David Sterba wrote:
> Add new block group profile to store 3 copies in a simliar way that
> current RAID1 does. The profile name is temporary and may change in the
> future.
>
> Signed-off-by: David Sterba <dsterba@xxxxxxxx>
> ---
> fs/btrfs/extent-tree.c | 6 +++++
> fs/btrfs/relocation.c | 1 +
> fs/btrfs/scrub.c | 3 ++-
> fs/btrfs/super.c | 3 +++
> fs/btrfs/volumes.c | 40 ++++++++++++++++++++++++++++-----
> fs/btrfs/volumes.h | 2 ++
> include/uapi/linux/btrfs.h | 3 ++-
> include/uapi/linux/btrfs_tree.h | 3 +++
> 8 files changed, 53 insertions(+), 8 deletions(-)
>
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 4ffa64e288da..47f929dcc3d4 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -7527,6 +7527,7 @@ static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
> if (!block_group_bits(block_group, flags)) {
> u64 extra = BTRFS_BLOCK_GROUP_DUP |
> BTRFS_BLOCK_GROUP_RAID1 |
> + BTRFS_BLOCK_GROUP_RAID1C3 |
> BTRFS_BLOCK_GROUP_RAID5 |
> BTRFS_BLOCK_GROUP_RAID6 |
> BTRFS_BLOCK_GROUP_RAID10;
"extra" could be created iterating on btrfs_raid_array[] and considering only the item with ncopies > 1; or we could add
#define BTRFS_BLOCK_GROUP_REDUNDANCY (BTRFS_BLOCK_GROUP_DUP| .....)
This constant could be used also below
> @@ -9330,6 +9331,8 @@ static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags)
>
> num_devices = fs_info->fs_devices->rw_devices;
>
> + ASSERT(!(flags & BTRFS_BLOCK_GROUP_RAID1C3));
> +
> stripped = BTRFS_BLOCK_GROUP_RAID0 |
> BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
> BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
> @@ -9647,6 +9650,8 @@ int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr)
> min_free >>= 1;
> } else if (index == BTRFS_RAID_RAID1) {
> dev_min = 2;
> + } else if (index == BTRFS_RAID_RAID1C3) {
> + dev_min = 3;
> } else if (index == BTRFS_RAID_DUP) {
> /* Multiply by 2 */
> min_free <<= 1;
The "if"s above could be simplified as:
dev_min = btrfs_raid_array[index].devs_min;
if (index == BTRFS_RAID_DUP)
min_free <<= 1;
else if (index == BTRFS_RAID_RAID0)
min_free = div64_u64(min_free, dev_min);
else if (index == BTRFS_RAID_RAID10)
min_free >>= 1;
> @@ -10141,6 +10146,7 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info)
> if (!(get_alloc_profile(info, space_info->flags) &
> (BTRFS_BLOCK_GROUP_RAID10 |
> BTRFS_BLOCK_GROUP_RAID1 |
> + BTRFS_BLOCK_GROUP_RAID1C3 |
> BTRFS_BLOCK_GROUP_RAID5 |
> BTRFS_BLOCK_GROUP_RAID6 |
> BTRFS_BLOCK_GROUP_DUP)))
See above about BTRFS_BLOCK_GROUP_REDUNDANCY
> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> index 879b76fa881a..fea9e7e96b87 100644
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -4339,6 +4339,7 @@ static void describe_relocation(struct btrfs_fs_info *fs_info,
> DESCRIBE_FLAG(METADATA, "metadata");
The code below, could be performed searching in the array btrfs_raid_array[] instead of checking each possibility
> DESCRIBE_FLAG(RAID0, "raid0");
> DESCRIBE_FLAG(RAID1, "raid1");
> + DESCRIBE_FLAG(RAID1C3, "raid1c3");
> DESCRIBE_FLAG(DUP, "dup");
> DESCRIBE_FLAG(RAID10, "raid10");
> DESCRIBE_FLAG(RAID5, "raid5");
> diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
> index 572306036477..e9355759f2ec 100644
> --- a/fs/btrfs/scrub.c
> +++ b/fs/btrfs/scrub.c
> @@ -3388,7 +3388,8 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
> offset = map->stripe_len * (num / map->sub_stripes);
> increment = map->stripe_len * factor;
> mirror_num = num % map->sub_stripes + 1;
> - } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
> + } else if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
> + BTRFS_BLOCK_GROUP_RAID1C3)) {
> increment = map->stripe_len;
> mirror_num = num % map->num_stripes + 1;
> } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
> index 4f646b66cc06..86e6aa5ef788 100644
> --- a/fs/btrfs/super.c
> +++ b/fs/btrfs/super.c
> @@ -1977,6 +1977,9 @@ static int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
> } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
> min_stripes = 2;
> num_stripes = 2;
> + } else if (type & BTRFS_BLOCK_GROUP_RAID1C3) {
> + min_stripes = 3;
> + num_stripes = 3;
> } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
> min_stripes = 4;
> num_stripes = 4;
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 45635f4d78c8..0920b31e999d 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -116,6 +116,18 @@ const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
> .bg_flag = BTRFS_BLOCK_GROUP_RAID6,
> .mindev_error = BTRFS_ERROR_DEV_RAID6_MIN_NOT_MET,
> },
> + [BTRFS_RAID_RAID1C3] = {
> + .sub_stripes = 1,
> + .dev_stripes = 1,
> + .devs_max = 0,
> + .devs_min = 3,
> + .tolerated_failures = 2,
> + .devs_increment = 3,
> + .ncopies = 3,
> + .raid_name = "raid1c3",
> + .bg_flag = BTRFS_BLOCK_GROUP_RAID1C3,
> + .mindev_error = BTRFS_ERROR_DEV_RAID1C3_MIN_NOT_MET,
> + },
> };
>
> const char *get_raid_name(enum btrfs_raid_types type)
> @@ -3336,6 +3348,8 @@ static int chunk_drange_filter(struct extent_buffer *leaf,
> if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
> BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) {
> factor = num_stripes / 2;
> + } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID1C3) {
> + factor = num_stripes / 3;
> } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID5) {
> factor = num_stripes - 1;
> } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID6) {
May be time to add two other fields to the btrfs_raid_array[] array ? I.e.:
factor_div and factor_sub
so factor could be computed as
index = btrfs_bg_flags_to_raid_index(btrfs_chunk_type(leaf, chunk))
factor = num_stripes / btrfs_raid_array[index].factor_div - btrfs_raid_array[index].factor_sub;
> @@ -3822,7 +3836,7 @@ int btrfs_balance(struct btrfs_fs_info *fs_info,
> if (num_devices > 1)
> allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
> if (num_devices > 2)
> - allowed |= BTRFS_BLOCK_GROUP_RAID5;
> + allowed |= BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID1C3;
> if (num_devices > 3)
> allowed |= (BTRFS_BLOCK_GROUP_RAID10 |
> BTRFS_BLOCK_GROUP_RAID6);
The "if"s below could be replaced by a search in the btrfs_raid_array[]
> @@ -3856,6 +3870,7 @@ int btrfs_balance(struct btrfs_fs_info *fs_info,
>
> /* allow to reduce meta or sys integrity only if force set */
> allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
> + BTRFS_BLOCK_GROUP_RAID1C3 |
> BTRFS_BLOCK_GROUP_RAID10 |
> BTRFS_BLOCK_GROUP_RAID5 |
> BTRFS_BLOCK_GROUP_RAID6;
See above about BTRFS_BLOCK_GROUP_REDUNDANCY
> @@ -4787,8 +4802,11 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
> sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
> btrfs_cmp_device_info, NULL);
>
> - /* round down to number of usable stripes */
> - ndevs = round_down(ndevs, devs_increment);
> + /*
> + * Round down to number of usable stripes, devs_increment can be any
> + * number so we can't use round_down()
> + */
> + ndevs -= ndevs % devs_increment;
>
> if (ndevs < devs_min) {
> ret = -ENOSPC;
> @@ -5075,6 +5093,8 @@ static inline int btrfs_chunk_max_errors(struct map_lookup *map)
> BTRFS_BLOCK_GROUP_RAID5 |
> BTRFS_BLOCK_GROUP_DUP)) {
> max_errors = 1;
> + } else if (map->type & BTRFS_BLOCK_GROUP_RAID1C3) {
> + max_errors = 2;
> } else if (map->type & BTRFS_BLOCK_GROUP_RAID6) {
> max_errors = 2;
> } else {
Even in this case the ifs above could be replaced with something like:
index = btrfs_bg_flags_to_raid_index(map->type)
max_errors = btrfs_raid_array[index].ncopies-1;
> @@ -5163,7 +5183,8 @@ int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
> return 1;
>
> map = em->map_lookup;
> - if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
> + if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
> + BTRFS_BLOCK_GROUP_RAID1C3))
> ret = map->num_stripes;
> else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
> ret = map->sub_stripes;
With the exception of RAID6 case (which I don't understand), the ifs above could be replaced with
index = btrfs_bg_flags_to_raid_index(map->type)
ret = btrfs_raid_array[index].ncopies
> @@ -5237,7 +5258,9 @@ static int find_live_mirror(struct btrfs_fs_info *fs_info,
> struct btrfs_device *srcdev;
>
> ASSERT((map->type &
> - (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)));
> + (BTRFS_BLOCK_GROUP_RAID1 |
> + BTRFS_BLOCK_GROUP_RAID1C3 |
> + BTRFS_BLOCK_GROUP_RAID10)));
>
> if (map->type & BTRFS_BLOCK_GROUP_RAID10)
> num_stripes = map->sub_stripes;
> @@ -5427,6 +5450,7 @@ static int __btrfs_map_block_for_discard(struct btrfs_fs_info *fs_info,
> div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
> last_stripe *= sub_stripes;
> } else if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
> + BTRFS_BLOCK_GROUP_RAID1C3 |
> BTRFS_BLOCK_GROUP_DUP)) {
> num_stripes = map->num_stripes;
> } else {
> @@ -5792,7 +5816,8 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
> &stripe_index);
> if (!need_full_stripe(op))
> mirror_num = 1;
> - } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
> + } else if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
> + BTRFS_BLOCK_GROUP_RAID1C3)) {
> if (need_full_stripe(op))
> num_stripes = map->num_stripes;
> else if (mirror_num)
> @@ -6441,6 +6466,7 @@ static int btrfs_check_chunk_valid(struct btrfs_fs_info *fs_info,
> }
> if ((type & BTRFS_BLOCK_GROUP_RAID10 && sub_stripes != 2) ||
> (type & BTRFS_BLOCK_GROUP_RAID1 && num_stripes < 1) ||
> + (type & BTRFS_BLOCK_GROUP_RAID1C3 && num_stripes < 3) ||
> (type & BTRFS_BLOCK_GROUP_RAID5 && num_stripes < 2) ||
> (type & BTRFS_BLOCK_GROUP_RAID6 && num_stripes < 3) ||
> (type & BTRFS_BLOCK_GROUP_DUP && num_stripes > 2) ||
The check above could be translate in specific check for BTRFS_BLOCK_GROUP_DUP and BTRFS_BLOCK_GROUP_RAID10; for the other cases we could check that num_stripes is >= devs_min
> @@ -7389,5 +7415,7 @@ int btrfs_bg_type_to_factor(u64 flags)
> if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
> BTRFS_BLOCK_GROUP_RAID10))
> return 2;
> + if (flags & BTRFS_BLOCK_GROUP_RAID1C3)
> + return 3;
> return 1;
> }
Even the function above could be replaced with something more general
int btrfs_bg_type_to_factor(u64 flags) {
if (flags & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6))
return 1;
return btrfs_raid_array[btrfs_bg_flags_to_raid_index(flags)]
}
> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
> index c7b9ad9733ea..5be624896dad 100644
> --- a/fs/btrfs/volumes.h
> +++ b/fs/btrfs/volumes.h
> @@ -537,6 +537,8 @@ static inline enum btrfs_raid_types btrfs_bg_flags_to_raid_index(u64 flags)
> return BTRFS_RAID_RAID10;
> else if (flags & BTRFS_BLOCK_GROUP_RAID1)
> return BTRFS_RAID_RAID1;
> + else if (flags & BTRFS_BLOCK_GROUP_RAID1C3)
> + return BTRFS_RAID_RAID1C3;
> else if (flags & BTRFS_BLOCK_GROUP_DUP)
> return BTRFS_RAID_DUP;
> else if (flags & BTRFS_BLOCK_GROUP_RAID0)
What about iterating on btrfs_raid_array[] in the above function
> diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
> index 5ca1d21fc4a7..137952d3375d 100644
> --- a/include/uapi/linux/btrfs.h
> +++ b/include/uapi/linux/btrfs.h
> @@ -825,7 +825,8 @@ enum btrfs_err_code {
> BTRFS_ERROR_DEV_TGT_REPLACE,
> BTRFS_ERROR_DEV_MISSING_NOT_FOUND,
> BTRFS_ERROR_DEV_ONLY_WRITABLE,
> - BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS
> + BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS,
> + BTRFS_ERROR_DEV_RAID1C3_MIN_NOT_MET,
> };
>
> #define BTRFS_IOC_SNAP_CREATE _IOW(BTRFS_IOCTL_MAGIC, 1, \
> diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h
> index aff1356c2bb8..fa75b63dd928 100644
> --- a/include/uapi/linux/btrfs_tree.h
> +++ b/include/uapi/linux/btrfs_tree.h
> @@ -836,6 +836,7 @@ struct btrfs_dev_replace_item {
> #define BTRFS_BLOCK_GROUP_RAID10 (1ULL << 6)
> #define BTRFS_BLOCK_GROUP_RAID5 (1ULL << 7)
> #define BTRFS_BLOCK_GROUP_RAID6 (1ULL << 8)
> +#define BTRFS_BLOCK_GROUP_RAID1C3 (1ULL << 9)
> #define BTRFS_BLOCK_GROUP_RESERVED (BTRFS_AVAIL_ALLOC_BIT_SINGLE | \
> BTRFS_SPACE_INFO_GLOBAL_RSV)
>
> @@ -847,6 +848,7 @@ enum btrfs_raid_types {
> BTRFS_RAID_SINGLE,
> BTRFS_RAID_RAID5,
> BTRFS_RAID_RAID6,
> + BTRFS_RAID_RAID1C3,
> BTRFS_NR_RAID_TYPES
> };
>
> @@ -856,6 +858,7 @@ enum btrfs_raid_types {
>
> #define BTRFS_BLOCK_GROUP_PROFILE_MASK (BTRFS_BLOCK_GROUP_RAID0 | \
> BTRFS_BLOCK_GROUP_RAID1 | \
> + BTRFS_BLOCK_GROUP_RAID1C3 | \
> BTRFS_BLOCK_GROUP_RAID5 | \
> BTRFS_BLOCK_GROUP_RAID6 | \
> BTRFS_BLOCK_GROUP_DUP | \
>
--
gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it>
Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5
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