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authorDavid Sterba <dsterba@suse.com>2018-03-02 22:56:53 +0100
committerDavid Sterba <dsterba@suse.com>2019-11-18 17:51:49 +0100
commit47e6f7423b9196ad6832d26cae52b7015f81ee7f (patch)
tree3f06408a77645e1546ed90445cf6584c515ca44d /fs
parentfac07d2b091542f7169978e4c1413747d8d0e965 (diff)
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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>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/ctree.h4
-rw-r--r--fs/btrfs/super.c2
-rw-r--r--fs/btrfs/volumes.c19
-rw-r--r--fs/btrfs/volumes.h2
4 files changed, 23 insertions, 4 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)