xfs: xfs_alloc_fix_freelist() can use incore perag structures

At the moment, xfs_alloc_fix_freelist() uses a mix of per-ag based
access and agf buffer  based access to freelist and space usage
information. However, once the AGF buffer is locked inside this
function, it is guaranteed that both the in-memory and on-disk
values are identical. xfs_alloc_fix_freelist() doesn't modify the
values in the structures directly, so it is a read-only user of the
infomration, and hence can use the per-ag structure exclusively for
determining what it should do.

This opens up an avenue for cleaning up a lot of duplicated logic
whose only difference is the structure it gets the data from, and in
doing so removes a lot of needless byte swapping overhead when
fixing up the free list.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 2 insertions, 6 deletions

diff --git a/fs/xfs/libxfs/xfs_alloc.h b/fs/xfs/libxfs/xfs_alloc.h
index d1b4b6a5c894..8815fc30f83d 100644
--- a/fs/xfs/libxfs/xfs_alloc.h
+++ b/fs/xfs/libxfs/xfs_alloc.h
@@ -128,12 +128,8 @@ typedef struct xfs_alloc_arg {
 #define XFS_ALLOC_USERDATA		1	/* allocation is for user data*/
 #define XFS_ALLOC_INITIAL_USER_DATA	2	/* special case start of file */
 
-/*
- * Find the length of the longest extent in an AG.
- */
-xfs_extlen_t
-xfs_alloc_longest_free_extent(struct xfs_mount *mp,
-		struct xfs_perag *pag);
+xfs_extlen_t xfs_alloc_longest_free_extent(struct xfs_mount *mp,
+		struct xfs_perag *pag, xfs_extlen_t need);
 
 /*
  * Compute and fill in value of m_ag_maxlevels.