When RAID1 is degraded, newer chunks should be degraded-RAID1
chunks instead of single chunks.
The bug is because the devs_min for raid1 was wrong it should
be 1, instead of 2.
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
---
fs/btrfs/volumes.c | 38 +++++++++++++++++++++++++++++++++-----
1 file changed, 33 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index e2b54d546b7c..8b87ed6eb381 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -56,7 +56,7 @@ const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
.sub_stripes = 1,
.dev_stripes = 1,
.devs_max = 2,
- .devs_min = 2,
+ .devs_min = 1,
.tolerated_failures = 1,
.devs_increment = 2,
.ncopies = 2,
@@ -4513,6 +4513,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
int i;
int j;
int index;
+ int missing_dev = 0;
BUG_ON(!alloc_profile_is_valid(type, 0));
@@ -4627,14 +4628,35 @@ 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 -= ndevs % devs_increment;
- if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
+ /*
+ * For raid1 and raid10; ndevs = devs_min, is less than
+ * (devs_increment * sub_stripes) = x in degraded mode.
+ * For rest of the RAIDs, x is 1
+ */
+ if (ndevs >= (devs_increment * sub_stripes)) {
+ /* round down to number of usable stripes */
+ ndevs -= ndevs % devs_increment;
+ }
+
+ /*
+ * Fix devs_min for RAID10
+ */
+ if (ndevs < devs_min) {
+ /* todo: look for better error reporting */
ret = -ENOSPC;
goto error;
}
+ /*
+ * For RAID1 and RAID10 if there is no sufficient dev for mirror
+ * or stripe, let the chunks be created in degraded mode.
+ * And for rest of RAIDs its fine as (devs_increment * sub_stripes)
+ * is 1.
+ */
+ if (ndevs < (devs_increment * sub_stripes))
+ missing_dev = (devs_increment * sub_stripes) - ndevs;
+
if (devs_max && ndevs > devs_max)
ndevs = devs_max;
/*
@@ -4645,11 +4667,17 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
num_stripes = ndevs * dev_stripes;
/*
- * this will have to be fixed for RAID1 and RAID10 over
+ * This will have to be fixed for RAID1 and RAID10 over
* more drives
*/
data_stripes = num_stripes / ncopies;
+ if (type & BTRFS_BLOCK_GROUP_RAID1) {
+ if (missing_dev) {
+ /* For RAID1 data_stripes is always 1 rather */
+ data_stripes = num_stripes;
+ }
+ }
if (type & BTRFS_BLOCK_GROUP_RAID5) {
raid_stripe_len = find_raid56_stripe_len(ndevs - 1,
btrfs_super_stripesize(info->super_copy));
--
2.7.0
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