2014-01-27 David Sterba <dsterba@xxxxxxx>: > On Mon, Jan 27, 2014 at 02:28:28PM +0100, Gerhard Heift wrote: >> To prevent unexpectet values in the unused fields of the search key fail early. >> Otherwise future extensions would break the behavior of the search if current >> implementations in userspace set them to values other than zero. >> >> Signed-off-by: Gerhard Heift <Gerhard@xxxxxxxxxx> >> --- a/fs/btrfs/ioctl.c >> +++ b/fs/btrfs/ioctl.c >> @@ -1947,6 +1947,9 @@ static noinline int search_ioctl(struct inode *inode, >> if (buf_size < sizeof(struct btrfs_ioctl_search_header)) >> return -EOVERFLOW; >> >> + if (sk->unused || sk->unused1 | sk->unused2 | sk->unused3 | sk->unused4) >> + return -EINVAL; > > The pattern that's been used for forward/backward compatibility is to > zero the unused or reserved fields on the userspace side and ignore them > completely in kernel. OK, I will dismiss this patch. > If any future version of the ioctl uses the now unused fields, it also > has to increase the version. Just for me to learn: If we have to increase the version, why do we have the unused fields anyway? We could expand the struct on demand if we need new fields. Do I miss something? -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
