btrfs-progs: do not enable extended refs in mkfs by default

This extref feature (lifting the single file hardlink limitation) is new
and not backward compatible with older kernels that are still in wide
use.

For now, use btrfstune to enable the feature, in the future it will be
possible to turn it on within mkfs by -O option.

Signed-off-by: David Sterba <dsterba@suse.cz>

diff --git a/mkfs.c b/mkfs.c
index 717c68f..96e9c4b 100644 (file)
--- a/mkfs.c
+++ b/mkfs.c
@@ -1528,7 +1528,6 @@ raid_groups:
 
        super = root->fs_info->super_copy;
        flags = btrfs_super_incompat_flags(super);
-       flags |= BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF;
 
        if (mixed)
                flags |= BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS;