linux-ext4 - Re: [PATCH 1/3] libext2fs: add 32-bit compat code for ext2fs_find_first_zero_generic

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Date:	Mon, 09 Apr 2012 09:14:41 -0700
From:	Eric Sandeen <sandeen@...hat.com>
To:	"Theodore Ts'o" <tytso@....edu>
CC:	Ext4 Developers List <linux-ext4@...r.kernel.org>,
	rjones@...hat.com, sami.liedes@....fi
Subject: Re: [PATCH 1/3] libext2fs: add 32-bit compat code for ext2fs_find_first_zero_generic_bmap()

On 4/6/12 11:59 AM, Theodore Ts'o wrote:
> The lack of 32-bit support was causing febootstrap to crash since it
> wasn't passing EXT2_FLAG_64BITS when opening the file system, so we
> were still using the legacy bitmaps.

Thanks Ted, these look good (and similar to the patch path I was going down)

-Eric

> Addresses-Red-Hat-Bugzilla: #808421
> 
> Signed-off-by: "Theodore Ts'o" <tytso@....edu>
> ---
>  lib/ext2fs/ext2fs.h       |    3 +++
>  lib/ext2fs/gen_bitmap.c   |   25 +++++++++++++++++++++++++
>  lib/ext2fs/gen_bitmap64.c |   32 ++++++++++++++++++++++++++++----
>  3 files changed, 56 insertions(+), 4 deletions(-)
> 
> diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
> index 68e94a3..fda6ade 100644
> --- a/lib/ext2fs/ext2fs.h
> +++ b/lib/ext2fs/ext2fs.h
> @@ -1169,6 +1169,9 @@ extern errcode_t ext2fs_set_generic_bitmap_range(ext2fs_generic_bitmap bmap,
>  						 errcode_t magic,
>  						 __u32 start, __u32 num,
>  						 void *in);
> +extern errcode_t ext2fs_find_first_zero_generic_bitmap(ext2fs_generic_bitmap bitmap,
> +						       __u32 start, __u32 end,
> +						       __u32 *out);
>  
>  /* gen_bitmap64.c */
>  
> diff --git a/lib/ext2fs/gen_bitmap.c b/lib/ext2fs/gen_bitmap.c
> index 6679bff..0bff854 100644
> --- a/lib/ext2fs/gen_bitmap.c
> +++ b/lib/ext2fs/gen_bitmap.c
> @@ -504,6 +504,30 @@ static int ext2fs_test_clear_generic_bitmap_range(ext2fs_generic_bitmap bitmap,
>  	return ext2fs_mem_is_zero(ADDR + start_byte, len_byte);
>  }
>  
> +errcode_t ext2fs_find_first_zero_generic_bitmap(ext2fs_generic_bitmap bitmap,
> +						__u32 start, __u32 end,
> +						__u32 *out)
> +{
> +	blk_t b;
> +
> +	if (start < bitmap->start || end > bitmap->end || start > end) {
> +		ext2fs_warn_bitmap2(bitmap, EXT2FS_TEST_ERROR, start);
> +		return EINVAL;
> +	}
> +
> +	while (start <= end) {
> +		b = ext2fs_test_bit(start - bitmap->start, bitmap->bitmap);
> +		if (!b) {
> +			*out = start;
> +			return 0;
> +		}
> +		start++;
> +	}
> +
> +	return ENOENT;
> +}
> +
> +
>  int ext2fs_test_block_bitmap_range(ext2fs_block_bitmap bitmap,
>  				   blk_t block, int num)
>  {
> @@ -558,3 +582,4 @@ void ext2fs_unmark_block_bitmap_range(ext2fs_block_bitmap bitmap,
>  		ext2fs_fast_clear_bit(block + i - bitmap->start,
>  				      bitmap->bitmap);
>  }
> +
> diff --git a/lib/ext2fs/gen_bitmap64.c b/lib/ext2fs/gen_bitmap64.c
> index e765d2c..07d6d52 100644
> --- a/lib/ext2fs/gen_bitmap64.c
> +++ b/lib/ext2fs/gen_bitmap64.c
> @@ -770,12 +770,36 @@ errcode_t ext2fs_find_first_zero_generic_bmap(ext2fs_generic_bitmap bitmap,
>  {
>  	int b;
>  
> -	if (bitmap->bitmap_ops->find_first_zero)
> -		return bitmap->bitmap_ops->find_first_zero(bitmap, start, end, out);
> +	if (!bitmap)
> +		return EINVAL;
>  
> -	if (!bitmap || !EXT2FS_IS_64_BITMAP(bitmap) || bitmap->cluster_bits)
> +	if (EXT2FS_IS_64_BITMAP(bitmap) && bitmap->bitmap_ops->find_first_zero)
> +		return bitmap->bitmap_ops->find_first_zero(bitmap, start,
> +							   end, out);
> +
> +	if (EXT2FS_IS_32_BITMAP(bitmap)) {
> +		blk_t blk = 0;
> +		errcode_t retval;
> +
> +		if (((start) & ~0xffffffffULL) ||
> +		    ((end) & ~0xffffffffULL)) {
> +			ext2fs_warn_bitmap2(bitmap, EXT2FS_TEST_ERROR, start);
> +			return EINVAL;
> +		}
> +
> +		retval = ext2fs_find_first_zero_generic_bitmap(bitmap, start,
> +							       end, &blk);
> +		if (retval == 0)
> +			*out = blk;
> +		return retval;
> +	}
> +
> +	if (!EXT2FS_IS_64_BITMAP(bitmap))
>  		return EINVAL;
>  
> +	start >>= bitmap->cluster_bits;
> +	end >>= bitmap->cluster_bits;
> +
>  	if (start < bitmap->start || end > bitmap->end || start > end) {
>  		warn_bitmap(bitmap, EXT2FS_TEST_ERROR, start);
>  		return EINVAL;
> @@ -784,7 +808,7 @@ errcode_t ext2fs_find_first_zero_generic_bmap(ext2fs_generic_bitmap bitmap,
>  	while (start <= end) {
>  		b = bitmap->bitmap_ops->test_bmap(bitmap, start);
>  		if (!b) {
> -			*out = start;
> +			*out = start << bitmap->cluster_bits;
>  			return 0;
>  		}
>  		start++;

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