xfs: remove the if_ext_max field in struct xfs_ifork

We spent a lot of effort to maintain this field, but it always equals to the
fork size divided by the constant size of an extent.  The prime use of it is
to assert that the two stay in sync.  Just divide the fork size by the extent
size in the few places that we actually use it and remove the overhead
of maintaining it.  Also introduce a few helpers to consolidate the places
where we actually care about the value.

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

1 files changed, 21 insertions, 22 deletions

diff --git a/fs/xfs/xfs_dfrag.c b/fs/xfs/xfs_dfrag.c
index 654dc6f..dd974a5 100644
--- a/fs/xfs/xfs_dfrag.c
+++ b/fs/xfs/xfs_dfrag.c
@@ -163,12 +163,14 @@ xfs_swap_extents_check_format(
 
 	/* Check temp in extent form to max in target */
 	if (tip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
-	    XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) > ip->i_df.if_ext_max)
+	    XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) >
+			XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
 		return EINVAL;
 
 	/* Check target in extent form to max in temp */
 	if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
-	    XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) > tip->i_df.if_ext_max)
+	    XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) >
+			XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
 		return EINVAL;
 
 	/*
@@ -180,18 +182,25 @@ xfs_swap_extents_check_format(
 	 * (a common defrag case) which will occur when the temp inode is in
 	 * extent format...
 	 */
-	if (tip->i_d.di_format == XFS_DINODE_FMT_BTREE &&
-	    ((XFS_IFORK_BOFF(ip) &&
-	      tip->i_df.if_broot_bytes > XFS_IFORK_BOFF(ip)) ||
-	     XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) <= ip->i_df.if_ext_max))
-		return EINVAL;
+	if (tip->i_d.di_format == XFS_DINODE_FMT_BTREE) {
+		if (XFS_IFORK_BOFF(ip) &&
+		    tip->i_df.if_broot_bytes > XFS_IFORK_BOFF(ip))
+			return EINVAL;
+		if (XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) <=
+		    XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
+			return EINVAL;
+	}
 
 	/* Reciprocal target->temp btree format checks */
-	if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE &&
-	    ((XFS_IFORK_BOFF(tip) &&
-	      ip->i_df.if_broot_bytes > XFS_IFORK_BOFF(tip)) ||
-	     XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) <= tip->i_df.if_ext_max))
-		return EINVAL;
+	if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE) {
+		if (XFS_IFORK_BOFF(tip) &&
+		    ip->i_df.if_broot_bytes > XFS_IFORK_BOFF(tip))
+			return EINVAL;
+
+		if (XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) <=
+		    XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
+			return EINVAL;
+	}
 
 	return 0;
 }
@@ -349,16 +358,6 @@ xfs_swap_extents(
 	*tifp = *tempifp;	/* struct copy */
 
 	/*
-	 * Fix the in-memory data fork values that are dependent on the fork
-	 * offset in the inode. We can't assume they remain the same as attr2
-	 * has dynamic fork offsets.
-	 */
-	ifp->if_ext_max = XFS_IFORK_SIZE(ip, XFS_DATA_FORK) /
-					(uint)sizeof(xfs_bmbt_rec_t);
-	tifp->if_ext_max = XFS_IFORK_SIZE(tip, XFS_DATA_FORK) /
-					(uint)sizeof(xfs_bmbt_rec_t);
-
-	/*
 	 * Fix the on-disk inode values
 	 */
 	tmp = (__uint64_t)ip->i_d.di_nblocks;