btrfs-progs: doc: update defrag page

- update wording for -t
- add optional argument to -c

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

1 files changed, 1 insertions, 1 deletions

diff --git a/cmds-filesystem.c b/cmds-filesystem.c
index 675e41df..db629d89 100644
--- a/cmds-filesystem.c
+++ b/cmds-filesystem.c
@@ -1065,7 +1065,7 @@ static const char * const cmd_defrag_usage[] = {
 	"-f             flush data to disk immediately after defragmenting",
 	"-s start       defragment only from byte onward",
 	"-l len         defragment only up to len bytes",
-	"-t size        minimal size of file to be considered for defragmenting",
+	"-t size        target extent size hint",
 	NULL
 };