xfs: return a distinct error code value for IGET_INCORE cache misses

For an XFS_IGET_INCORE iget operation, if the inode isn't in the cache,
return ENODATA so that we don't confuse it with the pre-existing ENOENT
cases (inode is in cache, but freed).

Signed-off-by: Darrick J. Wong <[email protected]>
Reviewed-by: Brian Foster <[email protected]>
Reviewed-by: Dave Chinner <[email protected]>

Author: djwong

fs/xfs/xfs_icache.c

@@ -610,7 +610,7 @@ xfs_iget(
 	} else {
 		rcu_read_unlock();
 		if (flags & XFS_IGET_INCORE) {
-			error = -ENOENT;
+			error = -ENODATA;
 			goto out_error_or_again;
 		}
 		XFS_STATS_INC(mp, xs_ig_missed);