btrfs-progs: doc: mkfs.btrfs: document -O^

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: David Sterba <dsterba@suse.cz>

diff --git a/Documentation/mkfs.btrfs.asciidoc b/Documentation/mkfs.btrfs.asciidoc
index fd20ca5..a9aa3cb 100644 (file)
--- a/Documentation/mkfs.btrfs.asciidoc
+++ b/Documentation/mkfs.btrfs.asciidoc
@@ -112,7 +112,7 @@ Do not perform whole device TRIM operation by default.
 
 -O|--features <feature1>[,<feature2>...]::
 A list of filesystem features turned on at mkfs time. Not all features are
-supported by old kernels.
+supported by old kernels. To disable a feature, prefix it with '^'.
 +
 To see all features run:
 +