[Ocfs2-tools-devel] [PATCH] o2image: return error if pread64 failed in ocfs2_image_load_bitmap()

[Joseph Qi]

Hi Jun,


On 16/12/21 17:33, piaojun wrote:
> In ocfs2_image_load_bitmap(), if pread64 failed, we need catch the
> errno and return errno to upper callers. otherwise we may get the
> incorrect 'arr_map' but 'o2image -I' execute successfully.
>
> Signed-off-by: Jun Piao <piaojun at huawei.com>
> ---
>   libocfs2/image.c | 15 ++++++++++-----
>   1 file changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/libocfs2/image.c b/libocfs2/image.c
> index fe95530..460616d 100644
> --- a/libocfs2/image.c
> +++ b/libocfs2/image.c
> @@ -163,7 +163,7 @@ errcode_t ocfs2_image_load_bitmap(ocfs2_filesys *ofs)
>   	struct ocfs2_image_state *ost;
>   	struct ocfs2_image_hdr *hdr;
>   	uint64_t blk_off, bits_set;
> -	int count, i, j, fd;
> +	int count = 0, tmp, i, j, fd;
>   	errcode_t ret;
>   	char *blk;
>   
> @@ -216,10 +216,15 @@ errcode_t ocfs2_image_load_bitmap(ocfs2_filesys *ofs)
>   		 * we don't use io_read_block as ocfs2 image bitmap block size
>   		 * could be different from filesystem block size
>   		 */
> -		count = pread64(fd, ost->ost_bmparr[i].arr_map,
> -				ost->ost_bmpblksz, blk_off);
> -		if (count < ost->ost_bmpblksz)
> -			goto out;
> +		while (count < ost->ost_bmpblksz) {
> +			tmp = pread64(fd, ost->ost_bmparr[i].arr_map + count,
> +				ost->ost_bmpblksz - count, blk_off + count);
> +			if (tmp <= 0) {
> +				ret = OCFS2_ET_IO;
> +				goto out;
> +			}
> +			count += tmp;
> +		}
In which case we need loop read?
Or shall we just set the error code if read fails?

Thanks,
Joseph
>   
>   		/* add bits set in this bitmap */
>   		for (j = 0; j < (ost->ost_bmpblksz * 8); j++)