On Mon, 11 May 2015 17:02:51 +1000, NeilBrown wrote:
> On Mon, 11 May 2015 01:31:43 +0900 (JST) Ryusuke Konishi
> <konishi.ryusuke@xxxxxxxxxxxxx> wrote:
>
>> On Fri, 08 May 2015 10:16:23 +1000, NeilBrown <neilb@xxxxxxx> wrote:
>> > The "fh_len" passed to ->fh_to_* is not guaranteed to be that same as
>> > that returned by encode_fh - it may be larger.
>> >
>> > With NFSv2, the filehandle is fixed length, so it may appear longer
>> > than expected and be zero-padded.
>> >
>> > So we must test that fh_len is at least some value, not exactly equal
>> > to it.
>> >
>> > Signed-off-by: NeilBrown <neilb@xxxxxxx>
>> > ---
>> > fs/nilfs2/namei.c | 6 +++---
>> > 1 file changed, 3 insertions(+), 3 deletions(-)
>> >
>> > diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c
>> > index 22180836ec22..b65fb79d16fd 100644
>> > --- a/fs/nilfs2/namei.c
>> > +++ b/fs/nilfs2/namei.c
>> > @@ -496,8 +496,8 @@ static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
>> > {
>> > struct nilfs_fid *fid = (struct nilfs_fid *)fh;
>> >
>> > - if ((fh_len != NILFS_FID_SIZE_NON_CONNECTABLE &&
>> > - fh_len != NILFS_FID_SIZE_CONNECTABLE) ||
>>
>> > + if ((fh_len < NILFS_FID_SIZE_NON_CONNECTABLE &&
>> > + fh_len < NILFS_FID_SIZE_CONNECTABLE) ||
>> > (fh_type != FILEID_NILFS_WITH_PARENT &&
>> > fh_type != FILEID_NILFS_WITHOUT_PARENT))
>> > return NULL;
>>
>> A bit weird. "fh_len < NILFS_FID_SIZE_CONNECTABLE" implies "fh_len <
>> NILFS_FID_SIZE_NON_CONNECTABLE".
>>
>> How about the following fix ?
>>
>> if ((fh_type != FILEID_NILFS_WITH_PARENT ||
>> fh_len < NILFS_FID_SIZE_CONNECTABLE) &&
>> (fh_type != FILEID_NILFS_WITHOUT_PARENT ||
>> fh_len < NILFS_FID_SIZE_NON_CONNECTABLE))
>> return NULL;
>>
>
> Yes, weird. The code only uses the early parts of the filehandle, so we
> only need to complain if the fh_len is less than FILEID_NILFS_WITHOUT_PARENT.
>
> So I'd prefer:
>
> @@ -496,8 +496,7 @@ static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
> {
> struct nilfs_fid *fid = (struct nilfs_fid *)fh;
>
> - if ((fh_len != NILFS_FID_SIZE_NON_CONNECTABLE &&
> - fh_len != NILFS_FID_SIZE_CONNECTABLE) ||
> + if (fh_len < NILFS_FID_SIZE_NON_CONNECTABLE ||
> (fh_type != FILEID_NILFS_WITH_PARENT &&
> fh_type != FILEID_NILFS_WITHOUT_PARENT))
> return NULL;
>
>
> Would you be OK with that? If so I'll resend.
>
> Thanks,
> NeilBrown
Thanks. This looks OK to me.
I'll apply it if you will resend.
Regards,
Ryusuke Konishi
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