xfs: hoist multi-fsb allocation unit detection to a helper

Replace the open-coded logic to decide if a file has a multi-fsb
allocation unit to a helper to make the code easier to read.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/xfs_bmap_util.c

@@ -542,7 +542,7 @@ xfs_can_free_eofblocks(
 	 * forever.
 	 */
 	end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_ISIZE(ip));
-	if (XFS_IS_REALTIME_INODE(ip) && mp->m_sb.sb_rextsize > 1)
+	if (xfs_inode_has_bigrtalloc(ip))
 		end_fsb = xfs_rtb_roundup_rtx(mp, end_fsb);
 	last_fsb = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes);
 	if (last_fsb <= end_fsb)
@@ -843,7 +843,7 @@ xfs_free_file_space(
 	endoffset_fsb = XFS_B_TO_FSBT(mp, offset + len);
 
 	/* We can only free complete realtime extents. */
-	if (XFS_IS_REALTIME_INODE(ip) && mp->m_sb.sb_rextsize > 1) {
+	if (xfs_inode_has_bigrtalloc(ip)) {
 		startoffset_fsb = xfs_rtb_roundup_rtx(mp, startoffset_fsb);
 		endoffset_fsb = xfs_rtb_rounddown_rtx(mp, endoffset_fsb);
 	}

fs/xfs/xfs_inode.h

@@ -311,6 +311,15 @@ static inline bool xfs_inode_has_large_extent_counts(struct xfs_inode *ip)
 	return ip->i_diflags2 & XFS_DIFLAG2_NREXT64;
 }
 
+/*
+ * Decide if this file is a realtime file whose data allocation unit is larger
+ * than a single filesystem block.
+ */
+static inline bool xfs_inode_has_bigrtalloc(struct xfs_inode *ip)
+{
+	return XFS_IS_REALTIME_INODE(ip) && ip->i_mount->m_sb.sb_rextsize > 1;
+}
+
 /*
  * Return the buftarg used for data allocations on a given inode.
  */