xfs: don't pass iomap flags to xfs_reflink_allocate_cow

Don't pass raw iomap flags to xfs_reflink_allocate_cow; signal our
intention with a boolean argument.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

fs/xfs/xfs_iomap.c

@@ -983,6 +983,7 @@ xfs_file_iomap_begin(
 	 */
 	if (xfs_is_cow_inode(ip)) {
 		struct xfs_bmbt_irec	orig = imap;
+		bool			directio = (flags & IOMAP_DIRECT);
 
 		/* if zeroing doesn't need COW allocation, then we are done. */
 		if ((flags & IOMAP_ZERO) &&
@@ -991,19 +992,19 @@ xfs_file_iomap_begin(
 
 		/* may drop and re-acquire the ilock */
 		error = xfs_reflink_allocate_cow(ip, &imap, &shared, &lockmode,
-						 flags);
+				directio);
 		if (error)
 			goto out_unlock;
 
 		/*
 		 * For buffered writes we need to report the address of the
 		 * previous block (if there was any) so that the higher level
-		 * write code can perform read-modify-write operations.  For
-		 * direct I/O code, which must be block aligned we need to
-		 * report the newly allocated address.
+		 * write code can perform read-modify-write operations; we
+		 * won't need the CoW fork mapping until writeback.  For direct
+		 * I/O, which must be block aligned, we need to report the
+		 * newly allocated address.
 		 */
-		if (!(flags & IOMAP_DIRECT) &&
-		    orig.br_startblock != HOLESTARTBLOCK)
+		if (!directio && orig.br_startblock != HOLESTARTBLOCK)
 			imap = orig;
 
 		end_fsb = imap.br_startoff + imap.br_blockcount;

fs/xfs/xfs_reflink.c

@@ -361,7 +361,7 @@ xfs_reflink_allocate_cow(
 	struct xfs_bmbt_irec	*imap,
 	bool			*shared,
 	uint			*lockmode,
-	unsigned		iomap_flags)
+	bool			convert_now)
 {
 	struct xfs_mount	*mp = ip->i_mount;
 	xfs_fileoff_t		offset_fsb = imap->br_startoff;
@@ -444,7 +444,7 @@ xfs_reflink_allocate_cow(
 	 * to initiate a disk write.  For direct I/O we are going to write the
 	 * data and need the conversion, but for buffered writes we're done.
 	 */
-	if (!(iomap_flags & IOMAP_DIRECT) || imap->br_state == XFS_EXT_NORM)
+	if (!convert_now || imap->br_state == XFS_EXT_NORM)
 		return 0;
 	trace_xfs_reflink_convert_cow(ip, imap);
 	return xfs_reflink_convert_cow_locked(ip, offset_fsb, count_fsb);

fs/xfs/xfs_reflink.h

@@ -27,7 +27,7 @@ bool xfs_inode_need_cow(struct xfs_inode *ip, struct xfs_bmbt_irec *imap,
 
 extern int xfs_reflink_allocate_cow(struct xfs_inode *ip,
 		struct xfs_bmbt_irec *imap, bool *shared, uint *lockmode,
-		unsigned iomap_flags);
+		bool convert_now);
 extern int xfs_reflink_convert_cow(struct xfs_inode *ip, xfs_off_t offset,
 		xfs_off_t count);