[PATCHv2 1/2] common: btrfs: Improve _require_btrfs_command

[Marcos Paulo de Souza <marcos.souza.org@gmail.com>]

From: Marcos Paulo de Souza <mpdesouza@suse.com>

Now _require_btrfs_command can also check for subfuntion options, like
"subvolume delete --subvolid".

Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
---

Changes from v1:
* New patch expanding the funtionality of _require_btrfs_command, which now
  check for argument of subcommands

 common/btrfs | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/common/btrfs b/common/btrfs
index 19ac7cc4..ae3142b6 100644
--- a/common/btrfs
+++ b/common/btrfs
@@ -12,12 +12,14 @@ _btrfs_get_subvolid()
 
 # _require_btrfs_command <command> [<subcommand>|<option>]
 # We check for btrfs and (optionally) features of the btrfs command
-# It can both subfunction like "inspect-internal dump-tree" and
-# options like "check --qgroup-report"
+# This function support both subfunction like "inspect-internal dump-tree" and
+# options like "check --qgroup-report", and also subfunction options like
+# "subvolume delete --subvolid"
 _require_btrfs_command()
 {
 	local cmd=$1
 	local param=$2
+	local param_arg=$3
 	local safe_param
 
 	_require_command "$BTRFS_UTIL_PROG" btrfs
@@ -39,6 +41,13 @@ _require_btrfs_command()
 
 	$BTRFS_UTIL_PROG $cmd $param --help &> /dev/null
 	[ $? -eq 0 ] || _notrun "$BTRFS_UTIL_PROG too old (must support $cmd $param)"
+
+	test -z "$param_arg" && return
+
+	# replace leading "-"s for grep
+	safe_param=$(echo $param_arg | sed 's/^-*//')
+	$BTRFS_UTIL_PROG $cmd $param --help | grep -wq $safe_param || \
+		_notrun "$BTRFS_UTIL_PROG too old (must support $cmd $param $param_arg)"
 }
 
 # Require extra check on btrfs qgroup numbers
-- 
2.24.0