Re: [PATCH v1 20/23] NFS: Account for XDR pad of buf->pages

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> On Apr 8, 2019, at 10:36 AM, Olga Kornievskaia <aglo@xxxxxxxxx> wrote:
> 
> On Fri, Apr 5, 2019 at 3:42 PM Chuck Lever <chuck.lever@xxxxxxxxxx> wrote:
>> 
>> 
>> 
>>> On Apr 5, 2019, at 3:27 PM, Olga Kornievskaia <aglo@xxxxxxxxx> wrote:
>>> 
>>> On Fri, Apr 5, 2019 at 3:23 PM Chuck Lever <chuck.lever@xxxxxxxxxx> wrote:
>>>> 
>>>> 
>>>> 
>>>>> On Apr 5, 2019, at 3:17 PM, Olga Kornievskaia <aglo@xxxxxxxxx> wrote:
>>>>> 
>>>>> On Fri, Apr 5, 2019 at 1:51 PM Chuck Lever <chuck.lever@xxxxxxxxxx> wrote:
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>>> On Apr 5, 2019, at 1:36 PM, Olga Kornievskaia <aglo@xxxxxxxxx> wrote:
>>>>>>> 
>>>>>>> Hi Chuck,
>>>>>>> 
>>>>>>> This patch break ACLs. After applying this patch nfs4_getfacl fails
>>>>>>> (it fails within xdr and returns ENOTSUPP). Any ideas why?
>>>>>> 
>>>>>> Possibly the macro that defines the maximum size of the reply
>>>>>> is incorrect.
>>>>>> 
>>>>> 
>>>>> This also breaks FS_LOCATION. I'm going to go on the limb here and say
>>>>> that it probably breaks whatever else it modified.
>>>> 
>>>> It modifies READ, READDIR, and READLINK. Are those broken?
>>> 
>>> I don't know how to test READLINK.. but I think READ/READDIR work OK
>>> otherwise folks would have noticed it (I gather ACL and FS_LOCATION
>>> testing doesn't happen frequently).
>> 
>> I guess I don't have any NFSv4 ACL or FS_LOCATIONS regressions
>> tests in my automated unit tests.
>> 
>> 
>>>>> The question is: can't we just revert it??
>>>> 
>>>> Why not "root cause" it first?
>>> 
>>> I'm trying :-/ I was just fishing to see how important the change was.
>> 
>> Try reverting just this hunk:
> 
> That doesn't help. It seems to be this piece that's causing issues
> hdrsize += RPC_REPHDRSIZE + req->rq_cred->cr_auth->au_rslack - 1
> 
> With this there is an extra byte (in front) in the buffer when (ACL)
> operation is decoded.

How do you know there isn't a latent bug in the getfacl decoder?

How are you reproducing this issue? I can try it here later today.


>> diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
>> index d0fa18d..6d9d5e2 100644
>> --- a/fs/nfs/nfs4xdr.c
>> +++ b/fs/nfs/nfs4xdr.c
>> @@ -284,14 +284,14 @@ static int decode_layoutget(struct xdr_stream *xdr, struct rpc_rqst *req,
>> #define decode_delegreturn_maxsz (op_decode_hdr_maxsz)
>> #define encode_getacl_maxsz     (encode_getattr_maxsz)
>> #define decode_getacl_maxsz     (op_decode_hdr_maxsz + \
>> -                                nfs4_fattr_bitmap_maxsz + 1)
>> +                                nfs4_fattr_bitmap_maxsz + 1 + 1)
>> #define encode_setacl_maxsz     (op_encode_hdr_maxsz + \
>>                                 encode_stateid_maxsz + 3)
>> #define decode_setacl_maxsz     (decode_setattr_maxsz)
>> #define encode_fs_locations_maxsz \
>>                                (encode_getattr_maxsz)
>> #define decode_fs_locations_maxsz \
>> -                               (0)
>> +                               (1)
>> #define encode_secinfo_maxsz    (op_encode_hdr_maxsz + nfs4_name_maxsz)
>> #define decode_secinfo_maxsz    (op_decode_hdr_maxsz + 1 + ((NFS_MAX_SECFLAVORS * (16 + GSS_OID_MAX_LEN)) / 4))
>> 
>> 
>>>>>>> On Mon, Feb 11, 2019 at 11:25 AM Chuck Lever <chuck.lever@xxxxxxxxxx> wrote:
>>>>>>>> 
>>>>>>>> Certain NFS results (eg. READLINK) might expect a data payload that
>>>>>>>> is not an exact multiple of 4 bytes. In this case, XDR encoding
>>>>>>>> is required to pad that payload so its length on the wire is a
>>>>>>>> multiple of 4 bytes. The constants that define the maximum size of
>>>>>>>> each NFS result do not appear to account for this extra word.
>>>>>>>> 
>>>>>>>> In each case where the data payload is to be received into pages:
>>>>>>>> 
>>>>>>>> - 1 word is added to the size of the receive buffer allocated by
>>>>>>>> call_allocate
>>>>>>>> 
>>>>>>>> - rpc_inline_rcv_pages subtracts 1 word from @hdrsize so that the
>>>>>>>> extra buffer space falls into the rcv_buf's tail iovec
>>>>>>>> 
>>>>>>>> - If buf->pagelen is word-aligned, an XDR pad is not needed and
>>>>>>>> is thus removed from the tail
>>>>>>>> 
>>>>>>>> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
>>>>>>>> ---
>>>>>>>> fs/nfs/nfs2xdr.c  |    6 +++---
>>>>>>>> fs/nfs/nfs3xdr.c  |   10 +++++-----
>>>>>>>> fs/nfs/nfs4xdr.c  |   15 ++++++++-------
>>>>>>>> net/sunrpc/clnt.c |    6 +++++-
>>>>>>>> net/sunrpc/xdr.c  |    2 ++
>>>>>>>> 5 files changed, 23 insertions(+), 16 deletions(-)
>>>>>>>> 
>>>>>>>> diff --git a/fs/nfs/nfs2xdr.c b/fs/nfs/nfs2xdr.c
>>>>>>>> index 1dcd0fe..a7ed29d 100644
>>>>>>>> --- a/fs/nfs/nfs2xdr.c
>>>>>>>> +++ b/fs/nfs/nfs2xdr.c
>>>>>>>> @@ -56,11 +56,11 @@
>>>>>>>> 
>>>>>>>> #define NFS_attrstat_sz                (1+NFS_fattr_sz)
>>>>>>>> #define NFS_diropres_sz                (1+NFS_fhandle_sz+NFS_fattr_sz)
>>>>>>>> -#define NFS_readlinkres_sz     (2)
>>>>>>>> -#define NFS_readres_sz         (1+NFS_fattr_sz+1)
>>>>>>>> +#define NFS_readlinkres_sz     (2+1)
>>>>>>>> +#define NFS_readres_sz         (1+NFS_fattr_sz+1+1)
>>>>>>>> #define NFS_writeres_sz         (NFS_attrstat_sz)
>>>>>>>> #define NFS_stat_sz            (1)
>>>>>>>> -#define NFS_readdirres_sz      (1)
>>>>>>>> +#define NFS_readdirres_sz      (1+1)
>>>>>>>> #define NFS_statfsres_sz       (1+NFS_info_sz)
>>>>>>>> 
>>>>>>>> static int nfs_stat_to_errno(enum nfs_stat);
>>>>>>>> diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
>>>>>>>> index a54dcf4..110358f 100644
>>>>>>>> --- a/fs/nfs/nfs3xdr.c
>>>>>>>> +++ b/fs/nfs/nfs3xdr.c
>>>>>>>> @@ -69,13 +69,13 @@
>>>>>>>> #define NFS3_removeres_sz      (NFS3_setattrres_sz)
>>>>>>>> #define NFS3_lookupres_sz      (1+NFS3_fh_sz+(2 * NFS3_post_op_attr_sz))
>>>>>>>> #define NFS3_accessres_sz      (1+NFS3_post_op_attr_sz+1)
>>>>>>>> -#define NFS3_readlinkres_sz    (1+NFS3_post_op_attr_sz+1)
>>>>>>>> -#define NFS3_readres_sz                (1+NFS3_post_op_attr_sz+3)
>>>>>>>> +#define NFS3_readlinkres_sz    (1+NFS3_post_op_attr_sz+1+1)
>>>>>>>> +#define NFS3_readres_sz                (1+NFS3_post_op_attr_sz+3+1)
>>>>>>>> #define NFS3_writeres_sz       (1+NFS3_wcc_data_sz+4)
>>>>>>>> #define NFS3_createres_sz      (1+NFS3_fh_sz+NFS3_post_op_attr_sz+NFS3_wcc_data_sz)
>>>>>>>> #define NFS3_renameres_sz      (1+(2 * NFS3_wcc_data_sz))
>>>>>>>> #define NFS3_linkres_sz                (1+NFS3_post_op_attr_sz+NFS3_wcc_data_sz)
>>>>>>>> -#define NFS3_readdirres_sz     (1+NFS3_post_op_attr_sz+2)
>>>>>>>> +#define NFS3_readdirres_sz     (1+NFS3_post_op_attr_sz+2+1)
>>>>>>>> #define NFS3_fsstatres_sz      (1+NFS3_post_op_attr_sz+13)
>>>>>>>> #define NFS3_fsinfores_sz      (1+NFS3_post_op_attr_sz+12)
>>>>>>>> #define NFS3_pathconfres_sz    (1+NFS3_post_op_attr_sz+6)
>>>>>>>> @@ -85,7 +85,7 @@
>>>>>>>> #define ACL3_setaclargs_sz     (NFS3_fh_sz+1+ \
>>>>>>>>                             XDR_QUADLEN(NFS_ACL_INLINE_BUFSIZE))
>>>>>>>> #define ACL3_getaclres_sz      (1+NFS3_post_op_attr_sz+1+ \
>>>>>>>> -                               XDR_QUADLEN(NFS_ACL_INLINE_BUFSIZE))
>>>>>>>> +                               XDR_QUADLEN(NFS_ACL_INLINE_BUFSIZE)+1)
>>>>>>>> #define ACL3_setaclres_sz      (1+NFS3_post_op_attr_sz)
>>>>>>>> 
>>>>>>>> static int nfs3_stat_to_errno(enum nfs_stat);
>>>>>>>> @@ -1629,7 +1629,7 @@ static int nfs3_xdr_dec_read3res(struct rpc_rqst *req, struct xdr_stream *xdr,
>>>>>>>>     result->op_status = status;
>>>>>>>>     if (status != NFS3_OK)
>>>>>>>>             goto out_status;
>>>>>>>> -       result->replen = 3 + ((xdr_stream_pos(xdr) - pos) >> 2);
>>>>>>>> +       result->replen = 4 + ((xdr_stream_pos(xdr) - pos) >> 2);
>>>>>>>>     error = decode_read3resok(xdr, result);
>>>>>>>> out:
>>>>>>>>     return error;
>>>>>>>> diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
>>>>>>>> index d0fa18d..6d9d5e2 100644
>>>>>>>> --- a/fs/nfs/nfs4xdr.c
>>>>>>>> +++ b/fs/nfs/nfs4xdr.c
>>>>>>>> @@ -215,14 +215,14 @@ static int decode_layoutget(struct xdr_stream *xdr, struct rpc_rqst *req,
>>>>>>>>                              nfs4_fattr_bitmap_maxsz)
>>>>>>>> #define encode_read_maxsz      (op_encode_hdr_maxsz + \
>>>>>>>>                              encode_stateid_maxsz + 3)
>>>>>>>> -#define decode_read_maxsz      (op_decode_hdr_maxsz + 2)
>>>>>>>> +#define decode_read_maxsz      (op_decode_hdr_maxsz + 2 + 1)
>>>>>>>> #define encode_readdir_maxsz   (op_encode_hdr_maxsz + \
>>>>>>>>                              2 + encode_verifier_maxsz + 5 + \
>>>>>>>>                             nfs4_label_maxsz)
>>>>>>>> #define decode_readdir_maxsz   (op_decode_hdr_maxsz + \
>>>>>>>> -                                decode_verifier_maxsz)
>>>>>>>> +                                decode_verifier_maxsz + 1)
>>>>>>>> #define encode_readlink_maxsz  (op_encode_hdr_maxsz)
>>>>>>>> -#define decode_readlink_maxsz  (op_decode_hdr_maxsz + 1)
>>>>>>>> +#define decode_readlink_maxsz  (op_decode_hdr_maxsz + 1 + 1)
>>>>>>>> #define encode_write_maxsz     (op_encode_hdr_maxsz + \
>>>>>>>>                              encode_stateid_maxsz + 4)
>>>>>>>> #define decode_write_maxsz     (op_decode_hdr_maxsz + \
>>>>>>>> @@ -284,14 +284,14 @@ static int decode_layoutget(struct xdr_stream *xdr, struct rpc_rqst *req,
>>>>>>>> #define decode_delegreturn_maxsz (op_decode_hdr_maxsz)
>>>>>>>> #define encode_getacl_maxsz    (encode_getattr_maxsz)
>>>>>>>> #define decode_getacl_maxsz    (op_decode_hdr_maxsz + \
>>>>>>>> -                                nfs4_fattr_bitmap_maxsz + 1)
>>>>>>>> +                                nfs4_fattr_bitmap_maxsz + 1 + 1)
>>>>>>>> #define encode_setacl_maxsz    (op_encode_hdr_maxsz + \
>>>>>>>>                              encode_stateid_maxsz + 3)
>>>>>>>> #define decode_setacl_maxsz    (decode_setattr_maxsz)
>>>>>>>> #define encode_fs_locations_maxsz \
>>>>>>>>                             (encode_getattr_maxsz)
>>>>>>>> #define decode_fs_locations_maxsz \
>>>>>>>> -                               (0)
>>>>>>>> +                               (1)
>>>>>>>> #define encode_secinfo_maxsz   (op_encode_hdr_maxsz + nfs4_name_maxsz)
>>>>>>>> #define decode_secinfo_maxsz   (op_decode_hdr_maxsz + 1 + ((NFS_MAX_SECFLAVORS * (16 + GSS_OID_MAX_LEN)) / 4))
>>>>>>>> 
>>>>>>>> @@ -392,12 +392,13 @@ static int decode_layoutget(struct xdr_stream *xdr, struct rpc_rqst *req,
>>>>>>>>                             1 /* opaque devaddr4 length */ + \
>>>>>>>>                               /* devaddr4 payload is read into page */ \
>>>>>>>>                             1 /* notification bitmap length */ + \
>>>>>>>> -                               1 /* notification bitmap, word 0 */)
>>>>>>>> +                               1 /* notification bitmap, word 0 */ + \
>>>>>>>> +                               1 /* possible XDR padding */)
>>>>>>>> #define encode_layoutget_maxsz (op_encode_hdr_maxsz + 10 + \
>>>>>>>>                             encode_stateid_maxsz)
>>>>>>>> #define decode_layoutget_maxsz (op_decode_hdr_maxsz + 8 + \
>>>>>>>>                             decode_stateid_maxsz + \
>>>>>>>> -                               XDR_QUADLEN(PNFS_LAYOUT_MAXSIZE))
>>>>>>>> +                               XDR_QUADLEN(PNFS_LAYOUT_MAXSIZE) + 1)
>>>>>>>> #define encode_layoutcommit_maxsz (op_encode_hdr_maxsz +          \
>>>>>>>>                             2 /* offset */ + \
>>>>>>>>                             2 /* length */ + \
>>>>>>>> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
>>>>>>>> index f780605..4ea38b0 100644
>>>>>>>> --- a/net/sunrpc/clnt.c
>>>>>>>> +++ b/net/sunrpc/clnt.c
>>>>>>>> @@ -1177,7 +1177,11 @@ void rpc_prepare_reply_pages(struct rpc_rqst *req, struct page **pages,
>>>>>>>>                          unsigned int base, unsigned int len,
>>>>>>>>                          unsigned int hdrsize)
>>>>>>>> {
>>>>>>>> -       hdrsize += RPC_REPHDRSIZE + req->rq_cred->cr_auth->au_rslack;
>>>>>>>> +       /* Subtract one to force an extra word of buffer space for the
>>>>>>>> +        * payload's XDR pad to fall into the rcv_buf's tail iovec.
>>>>>>>> +        */
>>>>>>>> +       hdrsize += RPC_REPHDRSIZE + req->rq_cred->cr_auth->au_rslack - 1;
>>>>>>>> +
>>>>>>>>     xdr_inline_pages(&req->rq_rcv_buf, hdrsize << 2, pages, base, len);
>>>>>>>>     trace_rpc_reply_pages(req);
>>>>>>>> }
>>>>>>>> diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
>>>>>>>> index 7cca515..aa8177d 100644
>>>>>>>> --- a/net/sunrpc/xdr.c
>>>>>>>> +++ b/net/sunrpc/xdr.c
>>>>>>>> @@ -189,6 +189,8 @@ __be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int nbytes)
>>>>>>>> 
>>>>>>>>     tail->iov_base = buf + offset;
>>>>>>>>     tail->iov_len = buflen - offset;
>>>>>>>> +       if ((xdr->page_len & 3) == 0)
>>>>>>>> +               tail->iov_len -= sizeof(__be32);
>>>>>>>> 
>>>>>>>>     xdr->buflen += len;
>>>>>>>> }
>>>>>>>> 
>>>>>> 
>>>>>> --
>>>>>> Chuck Lever
>>>> 
>>>> --
>>>> Chuck Lever
>> 
>> --
>> Chuck Lever

--
Chuck Lever







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