[PATCH 1/2 RESEND Rebased] btrfs-progs: add helper to create xattr name

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

This is a preparatory patch to add more xattr attributes, care a helper
function to alloc xattr name.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
 props.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/props.c b/props.c
index efa11180d4c5..3a498bd9e904 100644
--- a/props.c
+++ b/props.c
@@ -94,6 +94,21 @@ static int prop_label(enum prop_object_type type,
 	return ret;
 }
 
+static char *alloc_xattr_name(const char *name)
+{
+	char *xattr_name;
+
+	xattr_name = malloc(XATTR_BTRFS_PREFIX_LEN + strlen(name) + 1);
+	if (!xattr_name)
+		ERR_PTR(-ENOMEM);
+
+	memcpy(xattr_name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN);
+	memcpy(xattr_name + XATTR_BTRFS_PREFIX_LEN, name, strlen(name));
+	xattr_name[XATTR_BTRFS_PREFIX_LEN + strlen(name)] = '\0';
+
+	return xattr_name;
+}
+
 static int prop_compression(enum prop_object_type type,
 			    const char *object,
 			    const char *name,
@@ -114,14 +129,11 @@ static int prop_compression(enum prop_object_type type,
 		goto out;
 	}
 
-	xattr_name = malloc(XATTR_BTRFS_PREFIX_LEN + strlen(name) + 1);
-	if (!xattr_name) {
-		ret = -ENOMEM;
-		goto out;
+	xattr_name = alloc_xattr_name(name);
+	if (IS_ERR(xattr_name)) {
+		error("failed to alloc xattr_name %s: %m", object);
+		return PTR_ERR(xattr_name);
 	}
-	memcpy(xattr_name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN);
-	memcpy(xattr_name + XATTR_BTRFS_PREFIX_LEN, name, strlen(name));
-	xattr_name[XATTR_BTRFS_PREFIX_LEN + strlen(name)] = '\0';
 
 	if (value) {
 		if (strcmp(value, "no") == 0 || strcmp(value, "none") == 0)
-- 
1.8.3.1