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btrfs: add support for 3-copy replication (raid1c3) 

Add new block group profile to store 3 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-copy RAID1.

The minimum number of devices is 3, the maximum number of devices/chunks
that can be lost/damaged is 2. Like RAID6 but with 33% space
utilization.

Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2018-03-02 22:56:53 +01:00
parent fac07d2b09
commit 47e6f7423b
6 changed files with 30 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
fs/btrfs/ctree.h
View File

@ -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 RAID1 with 2 copies.
* Current value is derived from RAID1C3 with 3 copies.
*/
#define BTRFS_MAX_MIRRORS (2 + 1)
#define BTRFS_MAX_MIRRORS (3 + 1)
#define BTRFS_MAX_LEVEL 8

2
fs/btrfs/super.c
View File

@ -1935,6 +1935,8 @@ static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
num_stripes = nr_devices;
else if (type & BTRFS_BLOCK_GROUP_RAID1)
num_stripes = 2;
else if (type & BTRFS_BLOCK_GROUP_RAID1C3)
num_stripes = 3;
else if (type & BTRFS_BLOCK_GROUP_RAID10)
num_stripes = 4;

19
fs/btrfs/volumes.c
View File

@ -58,6 +58,18 @@ const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
.bg_flag = BTRFS_BLOCK_GROUP_RAID1,
.mindev_error = BTRFS_ERROR_DEV_RAID1_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,
},
[BTRFS_RAID_DUP] = {
.sub_stripes = 1,
.dev_stripes = 2,
@ -4839,8 +4851,11 @@ 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;

2
fs/btrfs/volumes.h
View File

@ -545,6 +545,8 @@ 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)

3
include/uapi/linux/btrfs.h
View File

@ -831,7 +831,8 @@ 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, \

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

@ -841,6 +841,7 @@ 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)
@ -852,6 +853,7 @@ enum btrfs_raid_types {
BTRFS_RAID_SINGLE,
BTRFS_RAID_RAID5,
BTRFS_RAID_RAID6,
BTRFS_RAID_RAID1C3,
BTRFS_NR_RAID_TYPES
};
@ -861,6 +863,7 @@ 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 | \
@ -868,7 +871,8 @@ enum btrfs_raid_types {
#define BTRFS_BLOCK_GROUP_RAID56_MASK (BTRFS_BLOCK_GROUP_RAID5 | \
BTRFS_BLOCK_GROUP_RAID6)
#define BTRFS_BLOCK_GROUP_RAID1_MASK (BTRFS_BLOCK_GROUP_RAID1)
#define BTRFS_BLOCK_GROUP_RAID1_MASK (BTRFS_BLOCK_GROUP_RAID1 | \
BTRFS_BLOCK_GROUP_RAID1C3)
/*
* We need a bit for restriper to be able to tell when chunks of type