[PATCH 2/2] growfs: clarify the man page a bit

While no RT section needs to exist for GROWFS_RT to work, the buftarg
must point to a block device already.

Signed-off-by: Christoph Hellwig <[email protected]>
---
 man/man8/xfs_growfs.8 | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/man/man8/xfs_growfs.8 b/man/man8/xfs_growfs.8
index d6e5fe13e943..1aa57fb0308f 100644
--- a/man/man8/xfs_growfs.8
+++ b/man/man8/xfs_growfs.8
@@ -151,7 +151,8 @@ the real-time section is grown to the largest size possible with the
 option. The filesystem does not need to have contained a real-time section
 before the
 .B xfs_growfs
-operation.
+operation, but it must have been mounted with the -o rtdev option pointing
+to a block device.
 .TP
 .B \-t
 Specifies an alternate mount table file (default is
-- 
2.53.0