xfs: create a helper to decide if a file mapping targets the rt volume

Create a helper so that we can stop open-coding this decision
everywhere.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/libxfs/xfs_bmap.c

@@ -4913,7 +4913,7 @@ xfs_bmap_del_extent_delay(
 
 	XFS_STATS_INC(mp, xs_del_exlist);
 
-	isrt = (whichfork == XFS_DATA_FORK) && XFS_IS_REALTIME_INODE(ip);
+	isrt = xfs_ifork_is_realtime(ip, whichfork);
 	del_endoff = del->br_startoff + del->br_blockcount;
 	got_endoff = got->br_startoff + got->br_blockcount;
 	da_old = startblockval(got->br_startblock);
@@ -5149,7 +5149,7 @@ xfs_bmap_del_extent_real(
 		return -ENOSPC;
 
 	*logflagsp = XFS_ILOG_CORE;
-	if (whichfork == XFS_DATA_FORK && XFS_IS_REALTIME_INODE(ip)) {
+	if (xfs_ifork_is_realtime(ip, whichfork)) {
 		if (!(bflags & XFS_BMAPI_REMAP)) {
 			error = xfs_rtfree_blocks(tp, del->br_startblock,
 					del->br_blockcount);
@@ -5396,7 +5396,7 @@ __xfs_bunmapi(
 		return 0;
 	}
 	XFS_STATS_INC(mp, xs_blk_unmap);
-	isrt = (whichfork == XFS_DATA_FORK) && XFS_IS_REALTIME_INODE(ip);
+	isrt = xfs_ifork_is_realtime(ip, whichfork);
 	end = start + len;
 
 	if (!xfs_iext_lookup_extent_before(ip, ifp, &end, &icur, &got)) {

fs/xfs/libxfs/xfs_inode_fork.c

@@ -813,3 +813,12 @@ xfs_iext_count_upgrade(
 
 	return 0;
 }
+
+/* Decide if a file mapping is on the realtime device or not. */
+bool
+xfs_ifork_is_realtime(
+	struct xfs_inode	*ip,
+	int			whichfork)
+{
+	return XFS_IS_REALTIME_INODE(ip) && whichfork != XFS_ATTR_FORK;
+}

fs/xfs/libxfs/xfs_inode_fork.h

@@ -260,6 +260,7 @@ int xfs_iext_count_may_overflow(struct xfs_inode *ip, int whichfork,
 		int nr_to_add);
 int xfs_iext_count_upgrade(struct xfs_trans *tp, struct xfs_inode *ip,
 		uint nr_to_add);
+bool xfs_ifork_is_realtime(struct xfs_inode *ip, int whichfork);
 
 /* returns true if the fork has extents but they are not read in yet. */
 static inline bool xfs_need_iread_extents(const struct xfs_ifork *ifp)

fs/xfs/scrub/bmap.c

@@ -924,7 +924,7 @@ xchk_bmap(
 	if (!ifp)
 		return -ENOENT;
 
-	info.is_rt = whichfork == XFS_DATA_FORK && XFS_IS_REALTIME_INODE(ip);
+	info.is_rt = xfs_ifork_is_realtime(ip, whichfork);
 	info.whichfork = whichfork;
 	info.is_shared = whichfork == XFS_DATA_FORK && xfs_is_reflink_inode(ip);
 	info.sc = sc;