[PATCH v7 1/5] btrfs: add btrfs_strmatch helper

[Anand Jain <anand.jain@oracle.com>]

Add a generic helper to match the golden-string in the given-string,
and ignore the leading and trailing whitespaces if any.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Suggested-by: David Sterba <dsterba@suse.com>
---
v5: born

 fs/btrfs/sysfs.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 93cf76118a04..7bb68cef98ab 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -809,6 +809,29 @@ static ssize_t btrfs_checksum_show(struct kobject *kobj,
 
 BTRFS_ATTR(, checksum, btrfs_checksum_show);
 
+/*
+ * Match the %golden in the %given. Ignore the leading and trailing whitespaces
+ * if any.
+ */
+static int btrfs_strmatch(const char *given, const char *golden)
+{
+	size_t len = strlen(golden);
+	char *stripped;
+
+	/* strip leading whitespace */
+	stripped = skip_spaces(given);
+
+	if (strncmp(stripped, golden, len) == 0) {
+		/* strip trailing whitespace */
+		if (strlen(skip_spaces(stripped + len)))
+			return -EINVAL;
+
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
 static const struct attribute *btrfs_attrs[] = {
 	BTRFS_ATTR_PTR(, label),
 	BTRFS_ATTR_PTR(, nodesize),
-- 
2.23.0