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[2/3] NILFS2: support NFSv2 export

Message ID 20150508001623.31129.25102.stgit@notabene.brown (mailing list archive)
State Not Applicable
Headers show

Commit Message

NeilBrown May 8, 2015, 12:16 a.m. UTC 
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@suse.de>
---
 fs/nilfs2/namei.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)



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Comments

Ryusuke Konishi May 10, 2015, 4:31 p.m. UTC | #1 
On Fri, 08 May 2015 10:16:23 +1000, NeilBrown <neilb@suse.de> 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@suse.de>
> ---
>  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;

Regards,
Ryusuke Konishi

> @@ -510,7 +510,7 @@ static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
>  {
>  	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
>  
> -	if (fh_len != NILFS_FID_SIZE_CONNECTABLE ||
> +	if (fh_len < NILFS_FID_SIZE_CONNECTABLE ||
>  	    fh_type != FILEID_NILFS_WITH_PARENT)
>  		return NULL;
>  
> 
> 
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NeilBrown May 11, 2015, 7:02 a.m. UTC | #2 
On Mon, 11 May 2015 01:31:43 +0900 (JST) Ryusuke Konishi
<konishi.ryusuke@lab.ntt.co.jp> wrote:

> On Fri, 08 May 2015 10:16:23 +1000, NeilBrown <neilb@suse.de> 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@suse.de>
> > ---
> >  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
Ryusuke Konishi May 11, 2015, 9:54 a.m. UTC | #3 
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@lab.ntt.co.jp> wrote:
> 
>> On Fri, 08 May 2015 10:16:23 +1000, NeilBrown <neilb@suse.de> 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@suse.de>
>> > ---
>> >  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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diff mbox

Patch

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;
@@ -510,7 +510,7 @@  static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
 {
 	struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 
-	if (fh_len != NILFS_FID_SIZE_CONNECTABLE ||
+	if (fh_len < NILFS_FID_SIZE_CONNECTABLE ||
 	    fh_type != FILEID_NILFS_WITH_PARENT)
 		return NULL;