1 files changed, 45 insertions, 13 deletions

diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c
index ca8aee6efe3..7a87d15523b 100644
--- a/fs/ext3/balloc.c
+++ b/fs/ext3/balloc.c
@@ -80,6 +80,14 @@ struct ext3_group_desc * ext3_get_group_desc(struct super_block * sb,
 	return desc + offset;
 }
 
+static inline int
+block_in_use(ext3_fsblk_t block, struct super_block *sb, unsigned char *map)
+{
+	return ext3_test_bit ((block -
+		le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) %
+			 EXT3_BLOCKS_PER_GROUP(sb), map);
+}
+
 /**
  * read_block_bitmap()
  * @sb:			super block
@@ -93,20 +101,51 @@ struct ext3_group_desc * ext3_get_group_desc(struct super_block * sb,
 static struct buffer_head *
 read_block_bitmap(struct super_block *sb, unsigned int block_group)
 {
+	int i;
 	struct ext3_group_desc * desc;
 	struct buffer_head * bh = NULL;
+	ext3_fsblk_t bitmap_blk;
 
 	desc = ext3_get_group_desc (sb, block_group, NULL);
 	if (!desc)
-		goto error_out;
-	bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap));
+		return NULL;
+	bitmap_blk = le32_to_cpu(desc->bg_block_bitmap);
+	bh = sb_bread(sb, bitmap_blk);
 	if (!bh)
-		ext3_error (sb, "read_block_bitmap",
+		ext3_error (sb, __FUNCTION__,
 			    "Cannot read block bitmap - "
 			    "block_group = %d, block_bitmap = %u",
 			    block_group, le32_to_cpu(desc->bg_block_bitmap));
-error_out:
+
+	/* check whether block bitmap block number is set */
+	if (!block_in_use(bitmap_blk, sb, bh->b_data)) {
+		/* bad block bitmap */
+		goto error_out;
+	}
+	/* check whether the inode bitmap block number is set */
+	bitmap_blk = le32_to_cpu(desc->bg_inode_bitmap);
+	if (!block_in_use(bitmap_blk, sb, bh->b_data)) {
+		/* bad block bitmap */
+		goto error_out;
+	}
+	/* check whether the inode table block number is set */
+	bitmap_blk = le32_to_cpu(desc->bg_inode_table);
+	for (i = 0; i < EXT3_SB(sb)->s_itb_per_group; i++, bitmap_blk++) {
+		if (!block_in_use(bitmap_blk, sb, bh->b_data)) {
+			/* bad block bitmap */
+			goto error_out;
+		}
+	}
+
 	return bh;
+
+error_out:
+	brelse(bh);
+	ext3_error(sb, __FUNCTION__,
+			"Invalid block bitmap - "
+			"block_group = %d, block = %lu",
+			block_group, bitmap_blk);
+	return NULL;
 }
 /*
  * The reservation window structure operations
@@ -570,7 +609,7 @@ do_more:
 		cpu_to_le16(le16_to_cpu(desc->bg_free_blocks_count) +
 			group_freed);
 	spin_unlock(sb_bgl_lock(sbi, block_group));
-	percpu_counter_mod(&sbi->s_freeblocks_counter, count);
+	percpu_counter_add(&sbi->s_freeblocks_counter, count);
 
 	/* We dirtied the bitmap block */
 	BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
@@ -1633,7 +1672,7 @@ allocated:
 	gdp->bg_free_blocks_count =
 			cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count)-num);
 	spin_unlock(sb_bgl_lock(sbi, group_no));
-	percpu_counter_mod(&sbi->s_freeblocks_counter, -num);
+	percpu_counter_sub(&sbi->s_freeblocks_counter, num);
 
 	BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor");
 	err = ext3_journal_dirty_metadata(handle, gdp_bh);
@@ -1733,13 +1772,6 @@ ext3_fsblk_t ext3_count_free_blocks(struct super_block *sb)
 #endif
 }
 
-static inline int
-block_in_use(ext3_fsblk_t block, struct super_block *sb, unsigned char *map)
-{
-	return ext3_test_bit ((block -
-		le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) %
-			 EXT3_BLOCKS_PER_GROUP(sb), map);
-}
 
 static inline int test_root(int a, int b)
 {