From 47e6f7423b9196ad6832d26cae52b7015f81ee7f Mon Sep 17 00:00:00 2001
From: David Sterba <dsterba@suse.com>
Date: Fri, 2 Mar 2018 22:56:53 +0100
Subject: [PATCH] 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>
---
fs/btrfs/ctree.h | 4 ++--
fs/btrfs/super.c | 2 ++
fs/btrfs/volumes.c | 19 +++++++++++++++++--
fs/btrfs/volumes.h | 2 ++
include/uapi/linux/btrfs.h | 3 ++-
include/uapi/linux/btrfs_tree.h | 6 +++++-
6 files changed, 30 insertions(+), 6 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 1c8f01eaf27c..aa1b437fb951 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -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
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 3f49407cc2aa..a5aff138e2e0 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -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;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index e6c458d99722..d17835fbd52f 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -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;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index ac4ba8c57283..a4e26b84e1b9 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -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)
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index 3ee0678c0a83..ba22f91a3f5b 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -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, \
diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h
index 5160be1d7332..52b2964b0311 100644
--- a/include/uapi/linux/btrfs_tree.h
+++ b/include/uapi/linux/btrfs_tree.h
@@ -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