On Nov 7, 2022, at 5:21 AM, Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx> wrote:
>
> From: Wang Shilong <wshilong@xxxxxxx>
>
> This adds the support in libext2fs to query whether the block range is
> valid or not (within range) given the block bitmap.
> Also to avoid duplicate warning messages in case of invalid blocks.
>
> This will be later used in pass1 of e2fsck is_blocks_used() function to
> check whether the given block range is valid or not to avoid duplicate
> warning resulting from ext2fs_test_block_bitmap_range2()
>
> Signed-off-by: Wang Shilong <wshilong@xxxxxxx>
> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
I don't think this patch is correct?
> ---
> diff --git a/lib/ext2fs/gen_bitmap64.c b/lib/ext2fs/gen_bitmap64.c
> index c31f942f..a9637cb5 100644
> --- a/lib/ext2fs/gen_bitmap64.c
> +++ b/lib/ext2fs/gen_bitmap64.c
> @@ -731,6 +731,39 @@ int ext2fs_test_block_bitmap_range2(ext2fs_block_bitmap gen_bmap,
> return bmap->bitmap_ops->test_clear_bmap_extent(bmap, block, num);
> }
>
> +int ext2fs_test_block_bitmap_range2_valid(ext2fs_block_bitmap bitmap,
> + blk64_t block, unsigned int num)
> +{
> + ext2fs_generic_bitmap_64 bmap = (ext2fs_generic_bitmap_64)bitmap;
> + __u64 end = block + num;
> +
> + if (!bmap)
> + return 0;
> +
> + if (EXT2FS_IS_32_BITMAP(bmap)) {
> + if ((block & ~0xffffffffULL) ||
> + ((block+num-1) & ~0xffffffffULL)) {
> + return 0;
> + }
> + }
This is bailing out early if the requested bit is > 2^32, but that is
before cluster conversion below. However, I think the bitmap is actually
stored in clusters, so the 2^32 check seems premature?
> +
> + if (!EXT2FS_IS_64_BITMAP(bmap))
> + return 0;
> +
> + /* convert to clusters if necessary */
> + block >>= bmap->cluster_bits;
> + end += (1 << bmap->cluster_bits) - 1;
> + end >>= bmap->cluster_bits;
> + num = end - block;
> +
> + if ((block < bmap->start) || (block > bmap->end) ||
> + (block+num-1 > bmap->end))
> + return 0;
> +
> + return 1;
> +}
Cheers, Andreas
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