4 files changed, 45 insertions, 15 deletions

diff --git a/sys/gnu/ext2fs/ext2_extern.h b/sys/gnu/ext2fs/ext2_extern.h
index 317f540af1e1..b37b3ec634ee 100644
--- a/sys/gnu/ext2fs/ext2_extern.h
+++ b/sys/gnu/ext2fs/ext2_extern.h
@@ -37,6 +37,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)ffs_extern.h	8.3 (Berkeley) 4/16/94
+ * $FreeBSD$
  */
 
 #ifndef _SYS_GNU_EXT2FS_EXT2_EXTERN_H_
@@ -78,6 +79,7 @@ int	ext2_dirempty __P((struct inode *, ino_t, struct ucred *));
 int	ext2_checkpath __P((struct inode *, struct inode *, struct ucred *));
 struct  ext2_group_desc * get_group_desc __P((struct mount * , 
 		unsigned int , struct buf ** ));
+int	ext2_group_sparse __P((int group));
 void	ext2_discard_prealloc __P((struct inode *));
 int	ext2_inactive __P((struct vop_inactive_args *));
 int	ext2_new_block __P ((struct mount * mp, unsigned long goal,
diff --git a/sys/gnu/ext2fs/ext2_fs.h b/sys/gnu/ext2fs/ext2_fs.h
index 64aff0d17bfc..8d5a56d00b61 100644
--- a/sys/gnu/ext2fs/ext2_fs.h
+++ b/sys/gnu/ext2fs/ext2_fs.h
@@ -509,7 +509,7 @@ struct ext2_super_block {
 					 EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
 					 EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
 #else
-#define EXT2_FEATURE_RO_COMPAT_SUPP	0
+#define EXT2_FEATURE_RO_COMPAT_SUPP	EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER
 #endif
 
 /*
diff --git a/sys/gnu/ext2fs/ext2_linux_balloc.c b/sys/gnu/ext2fs/ext2_linux_balloc.c
index 5c5c7006179e..cf2c0844ba4f 100644
--- a/sys/gnu/ext2fs/ext2_linux_balloc.c
+++ b/sys/gnu/ext2fs/ext2_linux_balloc.c
@@ -495,6 +495,25 @@ static __inline int block_in_use (unsigned long block,
 			 EXT2_BLOCKS_PER_GROUP(sb), map);
 }
 
+static int test_root(int a, int b)
+{
+	if (a == 0)
+		return 1;
+	while (1) {
+		if (a == 1)
+			return 1;
+		if (a % b)
+			return 0;
+		a = a / b;
+	}
+}
+
+int ext2_group_sparse(int group)
+{
+	return (test_root(group, 3) || test_root(group, 5) ||
+		test_root(group, 7));
+}
+
 #ifdef unused
 static void ext2_check_blocks_bitmap (struct mount * mp)
 {
@@ -520,15 +539,20 @@ static void ext2_check_blocks_bitmap (struct mount * mp)
 		bitmap_nr = load_block_bitmap (mp, i);
 		bh = sb->s_block_bitmap[bitmap_nr];
 
-		if (!test_bit (0, bh->b_data))
-			printf ( "ext2_check_blocks_bitmap: "
-				    "Superblock in group %d is marked free", i);
-
-		for (j = 0; j < desc_blocks; j++)
-			if (!test_bit (j + 1, bh->b_data))
+		if (!(es->s_feature_ro_compat &
+		     EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER) ||
+		    ext2_group_sparse(i)) {
+			if (!test_bit (0, bh->b_data))
 				printf ("ext2_check_blocks_bitmap: "
+					    "Superblock in group %d "
+					    "is marked free", i);
+
+			for (j = 0; j < desc_blocks; j++)
+				if (!test_bit (j + 1, bh->b_data))
+					printf ("ext2_check_blocks_bitmap: "
 					    "Descriptor block #%d in group "
 					    "%d is marked free", j, i);
+		}
 
 		if (!block_in_use (gdp->bg_block_bitmap, sb, bh->b_data))
 			printf ("ext2_check_blocks_bitmap: "
diff --git a/sys/gnu/ext2fs/ext2_vfsops.c b/sys/gnu/ext2fs/ext2_vfsops.c
index a56a443de578..4358a2d6fc7d 100644
--- a/sys/gnu/ext2fs/ext2_vfsops.c
+++ b/sys/gnu/ext2fs/ext2_vfsops.c
@@ -843,11 +843,10 @@ ext2_statfs(mp, sbp, p)
 	struct proc *p;
 {
         unsigned long overhead;
-	unsigned long overhead_per_group;
-
 	register struct ufsmount *ump;
 	register struct ext2_sb_info *fs;
 	register struct ext2_super_block *es;
+	int i, nsb;
 
 	ump = VFSTOUFS(mp);
 	fs = ump->um_e2fs;
@@ -859,13 +858,18 @@ ext2_statfs(mp, sbp, p)
 	/*
 	 * Compute the overhead (FS structures)
 	 */
-	overhead_per_group = 1 /* super block */ +
-			     fs->s_db_per_group +
-			     1 /* block bitmap */ +
-			     1 /* inode bitmap */ +
-			     fs->s_itb_per_group;
+	if (es->s_feature_ro_compat & EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER) {
+		nsb = 0;
+		for (i = 0 ; i < fs->s_groups_count; i++)
+			if (ext2_group_sparse(i))
+				nsb++;
+	} else
+		nsb = fs->s_groups_count;
 	overhead = es->s_first_data_block + 
-		   fs->s_groups_count * overhead_per_group;
+	    /* Superblocks and block group descriptors: */
+	    nsb * (1 + fs->s_db_per_group) +
+	    /* Inode bitmap, block bitmap, and inode table: */
+	    fs->s_groups_count * (1 + 1 + fs->s_itb_per_group);
 
 	sbp->f_bsize = EXT2_FRAG_SIZE(fs);	
 	sbp->f_iosize = EXT2_BLOCK_SIZE(fs);