diff mbox series

[02/15] btrfs: raid56: allow the exact minimum number of devices for balance convert

Message ID 69f7feedac4f0c6f4034927bf1a4a720586d0a71.1558085801.git.dsterba@suse.com (mailing list archive)
State New, archived
Headers show
Series RAID/volumes code cleanups | expand

Commit Message

David Sterba May 17, 2019, 9:43 a.m. UTC 
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 <dsterba@suse.com>
---
 fs/btrfs/volumes.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)
diff mbox series

Patch

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);