On Sun, Sep 01, 2019 at 03:08:23PM -0500, Goldwyn Rodrigues wrote: > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -37,6 +37,7 @@ struct vm_fault; > #define IOMAP_MAPPED 0x03 /* blocks allocated at @addr */ > #define IOMAP_UNWRITTEN 0x04 /* blocks allocated at @addr in unwritten state */ > #define IOMAP_INLINE 0x05 /* data inline in the inode */ > +#define IOMAP_COW 0x06 /* copy data from srcmap before writing */ I don't think IOMAP_COW can be a type - it is a flag given that we can do COW operations that allocate normal written extents (e.g. for direct I/O or DAX) and for delayed allocations.