Re: [PATCH v2 2/2] fs/ntfs3: fix lseek EINVAL on sparse/compressed files with 64-bit clusters

On 6/13/26 22:16, Senjin wrote:

> When CONFIG_NTFS3_64BIT_CLUSTER is enabled, sbi->maxbytes_sparse is set
> to -1. As a signed loff_t this is -1LL, the most negative value. Any
> lseek on a sparse or compressed file passes this as maxsize to
> vfs_setpos(), which returns -EINVAL whenever offset > maxsize, and
> since -1LL is less than any non-negative offset, every seek fails,
> including lseek(fd, 0, SEEK_SET).
>
> The intent of -1 here appears to be "no limit" (matching the spirit of
> MAX_LFS_FILESIZE assigned to sbi->maxbytes and sb->s_maxbytes in the
> same block), but the signed type makes it the minimum instead of the
> maximum.
>
> Fix by assigning MAX_LFS_FILESIZE to sbi->maxbytes_sparse in the
> 64-bit cluster path, consistent with the other two limits set there.
>
> Observed on a 16 TB NTFS volume with 0xFFFFFEFF total clusters compiled
> with CONFIG_NTFS3_64BIT_CLUSTER=y. Sequential reads via dd/cp worked
> correctly; any lseek call on sparse files returned EINVAL, preventing
> archive managers and other tools from random-accessing files on the
> volume. The non-64-bit-cluster path correctly sets maxbytes_sparse to
> (1ull << (cluster_bits + 32)) - 1, a large positive value.
>
> Signed-off-by: Senjin <[email protected]>
> ---
>   fs/ntfs3/super.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c
> index XXXXXXX..XXXXXXX 100644
> --- a/fs/ntfs3/super.c
> +++ b/fs/ntfs3/super.c
> @@ -1193,7 +1193,7 @@ static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
>   #ifdef CONFIG_NTFS3_64BIT_CLUSTER
>          if (clusters >= (1ull << (64 - cluster_bits)))
>                  sbi->maxbytes = -1;
> -       sbi->maxbytes_sparse = -1;
> +       sbi->maxbytes_sparse = MAX_LFS_FILESIZE;
>          sb->s_maxbytes = MAX_LFS_FILESIZE;
>   #else
>          /* Maximum size for sparse file. */
> --
> 2.x

Hello,

Sorry for the delay.
Your patch is applied, thank you.

Regards,
Konstantin