From 49cc180ca916cc3af9ab109a0497e86ccf20d641 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Fri, 17 May 2019 11:43:15 +0200 Subject: [PATCH] btrfs: raid56: allow the exact minimum number of devices for balance convert The minimum number of devices for RAID5 is 2, though this is only a bit expensive RAID1, and for RAID6 it's 3, which is a triple copy that works only 3 devices. mkfs.btrfs allows that and mounting such filesystem also works, so the conversion via balance filters is inconsistent with the others and we should not prevent it. Signed-off-by: David Sterba --- fs/btrfs/volumes.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 8508f6028c8d..10f7de0cc7e6 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4080,11 +4080,12 @@ int btrfs_balance(struct btrfs_fs_info *fs_info, allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE | BTRFS_BLOCK_GROUP_DUP; if (num_devices > 1) allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1); - if (num_devices > 2) + if (num_devices >= 2) allowed |= BTRFS_BLOCK_GROUP_RAID5; + if (num_devices >= 3) + allowed |= BTRFS_BLOCK_GROUP_RAID6; if (num_devices > 3) - allowed |= (BTRFS_BLOCK_GROUP_RAID10 | - BTRFS_BLOCK_GROUP_RAID6); + allowed |= BTRFS_BLOCK_GROUP_RAID10; if (validate_convert_profile(&bctl->data, allowed)) { int index = btrfs_bg_flags_to_raid_index(bctl->data.target); -- 2.30.2