xfs: factor prid related codes into xfs_get_initial_prid()

It will be reused by the O_TMPFILE creation function.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

fs/xfs/xfs_inode.h

@@ -20,6 +20,7 @@
 
 #include "xfs_inode_buf.h"
 #include "xfs_inode_fork.h"
+#include "xfs_dinode.h"
 
 /*
  * Kernel only inode definitions
@@ -192,6 +193,15 @@ xfs_set_projid(struct xfs_inode *ip,
 	ip->i_d.di_projid_lo = (__uint16_t) (projid & 0xffff);
 }
 
+static inline prid_t
+xfs_get_initial_prid(struct xfs_inode *dp)
+{
+	if (dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT)
+		return xfs_get_projid(dp);
+
+	return XFS_PROJID_DEFAULT;
+}
+
 /*
  * In-core inode flags.
  */