btrfs: document byte swap optimization of root_item::flags accessors

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

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index d78cb2d..a3b628e 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2216,11 +2216,13 @@ BTRFS_SETGET_STACK_FUNCS(root_rtransid, struct btrfs_root_item,
 
 static inline bool btrfs_root_readonly(const struct btrfs_root *root)
 {
+       /* Byte-swap the constant at compile time, root_item::flags is LE */
        return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_RDONLY)) != 0;
 }
 
 static inline bool btrfs_root_dead(const struct btrfs_root *root)
 {
+       /* Byte-swap the constant at compile time, root_item::flags is LE */
        return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_DEAD)) != 0;
 }