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btrfs: add support for 4-copy replication (raid1c4)

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Add new block group profile to store 4 copies in a simliar way that
current RAID1 does.  The profile attributes and constraints are defined
in the raid table and used by the same code that already handles the 2-
and 3-copy RAID1.

The minimum number of devices is 4, the maximum number of devices/chunks
that can be lost/damaged is 3. There is no comparable traditional RAID
level, the profile is added for future needs to accompany triple-parity
and beyond.

Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2018-03-02 22:56:53 +01:00
parent 47e6f7423b
commit 8d6fac0087
6 changed files with 24 additions and 3 deletions
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4
fs/btrfs/ctree.h
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@ -57,9 +57,9 @@ struct btrfs_ref;
* filesystem data as well that can be used to read data in order to repair
* read errors on other disks.
*
* Current value is derived from RAID1C3 with 3 copies.
* Current value is derived from RAID1C4 with 4 copies.
*/
#define BTRFS_MAX_MIRRORS (3 + 1)
#define BTRFS_MAX_MIRRORS (4 + 1)
#define BTRFS_MAX_LEVEL 8

2
fs/btrfs/super.c
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@ -1937,6 +1937,8 @@ static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
num_stripes = 2;
else if (type & BTRFS_BLOCK_GROUP_RAID1C3)
num_stripes = 3;
else if (type & BTRFS_BLOCK_GROUP_RAID1C4)
num_stripes = 4;
else if (type & BTRFS_BLOCK_GROUP_RAID10)
num_stripes = 4;

12
fs/btrfs/volumes.c
View File

@ -70,6 +70,18 @@ const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
.bg_flag = BTRFS_BLOCK_GROUP_RAID1C3,
.mindev_error = BTRFS_ERROR_DEV_RAID1C3_MIN_NOT_MET,
},
[BTRFS_RAID_RAID1C4] = {
.sub_stripes = 1,
.dev_stripes = 1,
.devs_max = 0,
.devs_min = 4,
.tolerated_failures = 3,
.devs_increment = 4,
.ncopies = 4,
.raid_name = "raid1c4",
.bg_flag = BTRFS_BLOCK_GROUP_RAID1C4,
.mindev_error = BTRFS_ERROR_DEV_RAID1C4_MIN_NOT_MET,
},
[BTRFS_RAID_DUP] = {
.sub_stripes = 1,
.dev_stripes = 2,

2
fs/btrfs/volumes.h
View File

@ -547,6 +547,8 @@ static inline enum btrfs_raid_types btrfs_bg_flags_to_raid_index(u64 flags)
return BTRFS_RAID_RAID1;
else if (flags & BTRFS_BLOCK_GROUP_RAID1C3)
return BTRFS_RAID_RAID1C3;
else if (flags & BTRFS_BLOCK_GROUP_RAID1C4)
return BTRFS_RAID_RAID1C4;
else if (flags & BTRFS_BLOCK_GROUP_DUP)
return BTRFS_RAID_DUP;
else if (flags & BTRFS_BLOCK_GROUP_RAID0)

1
include/uapi/linux/btrfs.h
View File

@ -833,6 +833,7 @@ enum btrfs_err_code {
BTRFS_ERROR_DEV_ONLY_WRITABLE,
BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS,
BTRFS_ERROR_DEV_RAID1C3_MIN_NOT_MET,
BTRFS_ERROR_DEV_RAID1C4_MIN_NOT_MET,
};
#define BTRFS_IOC_SNAP_CREATE _IOW(BTRFS_IOCTL_MAGIC, 1, \

6
include/uapi/linux/btrfs_tree.h
View File

@ -842,6 +842,7 @@ struct btrfs_dev_replace_item {
#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_RAID1C4 (1ULL << 10)
#define BTRFS_BLOCK_GROUP_RESERVED (BTRFS_AVAIL_ALLOC_BIT_SINGLE | \
BTRFS_SPACE_INFO_GLOBAL_RSV)
@ -854,6 +855,7 @@ enum btrfs_raid_types {
BTRFS_RAID_RAID5,
BTRFS_RAID_RAID6,
BTRFS_RAID_RAID1C3,
BTRFS_RAID_RAID1C4,
BTRFS_NR_RAID_TYPES
};
@ -864,6 +866,7 @@ 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_RAID1C4 | \
BTRFS_BLOCK_GROUP_RAID5 | \
BTRFS_BLOCK_GROUP_RAID6 | \
BTRFS_BLOCK_GROUP_DUP | \
@ -872,7 +875,8 @@ enum btrfs_raid_types {
BTRFS_BLOCK_GROUP_RAID6)
#define BTRFS_BLOCK_GROUP_RAID1_MASK (BTRFS_BLOCK_GROUP_RAID1 | \
BTRFS_BLOCK_GROUP_RAID1C3)
BTRFS_BLOCK_GROUP_RAID1C3 | \
BTRFS_BLOCK_GROUP_RAID1C4)
/*
* We need a bit for restriper to be able to tell when chunks of type