xfs: simplify the fallocate path

Call xfs_alloc_file_space or xfs_free_file_space directly from
xfs_file_fallocate instead of going through xfs_change_file_space.

This simplified the code by removing the unessecary marshalling of the
arguments into an xfs_flock64_t structure and allows removing checks that
are already done in the VFS code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index bdd552d..7e1c2ae 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -965,28 +965,9 @@
 	return error;
 }
 
-/*
- * xfs_alloc_file_space()
- *      This routine allocates disk space for the given file.
- *
- *	If alloc_type == 0, this request is for an ALLOCSP type
- *	request which will change the file size.  In this case, no
- *	DMAPI event will be generated by the call.  A TRUNCATE event
- *	will be generated later by xfs_setattr.
- *
- *	If alloc_type != 0, this request is for a RESVSP type
- *	request, and a DMAPI DM_EVENT_WRITE will be generated if the
- *	lower block boundary byte address is less than the file's
- *	length.
- *
- * RETURNS:
- *       0 on success
- *      errno on error
- *
- */
-STATIC int
+int
 xfs_alloc_file_space(
-	xfs_inode_t		*ip,
+	struct xfs_inode	*ip,
 	xfs_off_t		offset,
 	xfs_off_t		len,
 	int			alloc_type)
@@ -1231,21 +1212,9 @@
 	return error;
 }
 
-/*
- * xfs_free_file_space()
- *      This routine frees disk space for the given file.
- *
- *	This routine is only called by xfs_change_file_space
- *	for an UNRESVSP type call.
- *
- * RETURNS:
- *       0 on success
- *      errno on error
- *
- */
-STATIC int
+int
 xfs_free_file_space(
-	xfs_inode_t		*ip,
+	struct xfs_inode	*ip,
 	xfs_off_t		offset,
 	xfs_off_t		len)
 {