Re: [PATCH 1/2] NFSD: added FREE_STATEID operation

[Bryan Schumaker <bjschuma@netapp.com>]

On 05/09/2011 08:36 PM, J. Bruce Fields wrote:
> On Fri, May 06, 2011 at 02:57:34PM -0400, bjschuma@netapp.com wrote:
>> From: Bryan Schumaker <bjschuma@netapp.com>
>>
>> This operation is used by the client to tell the server to free a
>> stateid.
>>
>> Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
>> ---
>>  fs/nfsd/nfs4proc.c  |    5 ++++
>>  fs/nfsd/nfs4state.c |   56 +++++++++++++++++++++++++++++++++++++++++++++++++++
>>  fs/nfsd/nfs4xdr.c   |   32 +++++++++++++++++++++++++++-
>>  fs/nfsd/xdr4.h      |    8 +++++++
>>  4 files changed, 99 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
>> index 3a6dbd7..7e00116 100644
>> --- a/fs/nfsd/nfs4proc.c
>> +++ b/fs/nfsd/nfs4proc.c
>> @@ -1412,6 +1412,11 @@ static struct nfsd4_operation nfsd4_ops[] = {
>>  		.op_flags = OP_HANDLES_WRONGSEC,
>>  		.op_name = "OP_SECINFO_NO_NAME",
>>  	},
>> +	[OP_FREE_STATEID] = {
>> +		.op_func = (nfsd4op_func)nfsd4_free_stateid,
>> +		.op_flags = ALLOWED_WITHOUT_FH,
>> +		.op_name = "OP_FREE_STATEID",
>> +	},
>>  };
>>  
>>  static const char *nfsd4_op_name(unsigned opnum)
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index a2ea14f..6beec13 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -60,6 +60,7 @@ static u64 current_sessionid = 1;
>>  
>>  /* forward declarations */
>>  static struct nfs4_stateid * find_stateid(stateid_t *stid, int flags);
>> +static struct nfs4_stateid * search_for_stateid(stateid_t *stid);
>>  static struct nfs4_delegation * find_delegation_stateid(struct inode *ino, stateid_t *stid);
>>  static char user_recovery_dirname[PATH_MAX] = "/var/lib/nfs/v4recovery";
>>  static void nfs4_set_recdir(char *recdir);
>> @@ -316,6 +317,12 @@ static struct list_head	unconf_id_hashtbl[CLIENT_HASH_SIZE];
>>  static struct list_head client_lru;
>>  static struct list_head close_lru;
>>  
>> +static int
>> +stateid_has_locks(struct nfs4_stateid *stp)
>> +{
>> +	return list_empty(&stp->st_lockowners);
>> +}
> 
> There may be lockowners that aren't associated with any current locks.
> 
> The only way we have to check this currently is to walk through the
> i_flock list for the given inode, like check_for_locks() does.  That may
> be the expedient thing to do for now.

Ok, I'll change it to use check_for_locks() for now.

> 
> (It would be simpler if we could, say, keep a count of the locks
> associated with each lock stateid.  That's not as easy as it sounds,
> thanks to merging and splitting of byte-range locks.  But we could use
> callbacks from locks.c to do it.  I think that's what I'd really like to
> do.)
> 
>> +
>>  /*
>>   * We store the NONE, READ, WRITE, and BOTH bits separately in the
>>   * st_{access,deny}_bmap field of the stateid, in order to track not
>> @@ -3212,6 +3219,33 @@ out:
>>  	return status;
>>  }
>>  
>> +/*
>> + * Free a state id
>> + */
>> +__be32
>> +nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>> +		   struct nfsd4_free_stateid *free_stateid)
>> +{
>> +	struct nfs4_stateid *stp = NULL;
>> +	stateid_t *stateid = &free_stateid->fr_stateid;
>> +
>> +	stp = search_for_stateid(stateid);
>> +	if (!stp)
>> +		return nfserr_bad_stateid;
>> +	if (stateid->si_generation != 0) {
>> +		if (stateid->si_generation < stp->st_stateid.si_generation)
>> +			return nfserr_old_stateid;
>> +		if (stateid->si_generation > stp->st_stateid.si_generation)
>> +			return nfserr_bad_stateid;
>> +	}
>> +
>> +	if (stateid_has_locks(stp))
>> +		return nfserr_locks_held;
>> +	if (stp)
> 
> Already checked this above.

Good catch, I'll remove the extra check.

> 
>> +		release_open_stateid(stp);
> 
> OK, but it might not be a lock stateid.  (I assume free_stateid can be
> called on *any* kind of stateid?)

I thought release_open_stateid() freed all stateids, not just the lock stateid...

> 
> --b.
> 
>> +	return nfs_ok;
>> +}
>> +
>>  static inline int
>>  setlkflg (int type)
>>  {
>> @@ -3619,6 +3653,28 @@ find_stateid(stateid_t *stid, int flags)
>>  	return NULL;
>>  }
>>  
>> +static struct nfs4_stateid *
>> +search_for_stateid(stateid_t *stid)
>> +{
>> +	struct nfs4_stateid *local;
>> +	u32 st_id = stid->si_stateownerid;
>> +	u32 f_id  = stid->si_fileid;
>> +	unsigned int hashval = stateid_hashval(st_id, f_id);
>> +
>> +	list_for_each_entry(local, &lockstateid_hashtbl[hashval], st_hash) {
>> +		if ((local->st_stateid.si_stateownerid == st_id) &&
>> +		    (local->st_stateid.si_fileid == f_id))
>> +			return local;
>> +	}
>> +
>> +	list_for_each_entry(local, &stateid_hashtbl[hashval], st_hash) {
>> +		if ((local->st_stateid.si_stateownerid == st_id) &&
>> +		    (local->st_stateid.si_fileid == f_id))
>> +			return local;
>> +	}
>> +	return NULL;
>> +}
>> +
>>  static struct nfs4_delegation *
>>  find_delegation_stateid(struct inode *ino, stateid_t *stid)
>>  {
>> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
>> index 195a91d..5da6874 100644
>> --- a/fs/nfsd/nfs4xdr.c
>> +++ b/fs/nfsd/nfs4xdr.c
>> @@ -1246,6 +1246,19 @@ nfsd4_decode_destroy_session(struct nfsd4_compoundargs *argp,
>>  }
>>  
>>  static __be32
>> +nfsd4_decode_free_stateid(struct nfsd4_compoundargs *argp,
>> +			  struct nfsd4_free_stateid *free_stateid)
>> +{
>> +	DECODE_HEAD;
>> +
>> +	READ_BUF(sizeof(stateid_t));
>> +	READ32(free_stateid->fr_stateid.si_generation);
>> +	COPYMEM(&free_stateid->fr_stateid.si_opaque, sizeof(stateid_opaque_t));
>> +
>> +	DECODE_TAIL;
>> +}
>> +
>> +static __be32
>>  nfsd4_decode_sequence(struct nfsd4_compoundargs *argp,
>>  		      struct nfsd4_sequence *seq)
>>  {
>> @@ -1370,7 +1383,7 @@ static nfsd4_dec nfsd41_dec_ops[] = {
>>  	[OP_EXCHANGE_ID]	= (nfsd4_dec)nfsd4_decode_exchange_id,
>>  	[OP_CREATE_SESSION]	= (nfsd4_dec)nfsd4_decode_create_session,
>>  	[OP_DESTROY_SESSION]	= (nfsd4_dec)nfsd4_decode_destroy_session,
>> -	[OP_FREE_STATEID]	= (nfsd4_dec)nfsd4_decode_notsupp,
>> +	[OP_FREE_STATEID]	= (nfsd4_dec)nfsd4_decode_free_stateid,
>>  	[OP_GET_DIR_DELEGATION]	= (nfsd4_dec)nfsd4_decode_notsupp,
>>  	[OP_GETDEVICEINFO]	= (nfsd4_dec)nfsd4_decode_notsupp,
>>  	[OP_GETDEVICELIST]	= (nfsd4_dec)nfsd4_decode_notsupp,
>> @@ -3115,6 +3128,21 @@ nfsd4_encode_destroy_session(struct nfsd4_compoundres *resp, int nfserr,
>>  	return nfserr;
>>  }
>>  
>> +static __be32
>> +nfsd4_encode_free_stateid(struct nfsd4_compoundres *resp, int nfserr,
>> +			  struct nfsd4_free_stateid *free_stateid)
>> +{
>> +	__be32 *p;
>> +
>> +	if (nfserr)
>> +		return nfserr;
>> +
>> +	RESERVE_SPACE(4);
>> +	WRITE32(nfserr);
>> +	ADJUST_ARGS();
>> +	return nfserr;
>> +}
>> +
>>  __be32
>>  nfsd4_encode_sequence(struct nfsd4_compoundres *resp, int nfserr,
>>  		      struct nfsd4_sequence *seq)
>> @@ -3196,7 +3224,7 @@ static nfsd4_enc nfsd4_enc_ops[] = {
>>  	[OP_EXCHANGE_ID]	= (nfsd4_enc)nfsd4_encode_exchange_id,
>>  	[OP_CREATE_SESSION]	= (nfsd4_enc)nfsd4_encode_create_session,
>>  	[OP_DESTROY_SESSION]	= (nfsd4_enc)nfsd4_encode_destroy_session,
>> -	[OP_FREE_STATEID]	= (nfsd4_enc)nfsd4_encode_noop,
>> +	[OP_FREE_STATEID]	= (nfsd4_enc)nfsd4_encode_free_stateid,
>>  	[OP_GET_DIR_DELEGATION]	= (nfsd4_enc)nfsd4_encode_noop,
>>  	[OP_GETDEVICEINFO]	= (nfsd4_enc)nfsd4_encode_noop,
>>  	[OP_GETDEVICELIST]	= (nfsd4_enc)nfsd4_encode_noop,
>> diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
>> index 366401e..ed1784d 100644
>> --- a/fs/nfsd/xdr4.h
>> +++ b/fs/nfsd/xdr4.h
>> @@ -342,6 +342,11 @@ struct nfsd4_setclientid_confirm {
>>  	nfs4_verifier	sc_confirm;
>>  };
>>  
>> +struct nfsd4_free_stateid {
>> +	stateid_t	fr_stateid;         /* request */
>> +	__be32		fr_status;          /* response */
>> +};
>> +
>>  /* also used for NVERIFY */
>>  struct nfsd4_verify {
>>  	u32		ve_bmval[3];        /* request */
>> @@ -432,6 +437,7 @@ struct nfsd4_op {
>>  		struct nfsd4_destroy_session	destroy_session;
>>  		struct nfsd4_sequence		sequence;
>>  		struct nfsd4_reclaim_complete	reclaim_complete;
>> +		struct nfsd4_free_stateid	free_stateid;
>>  	} u;
>>  	struct nfs4_replay *			replay;
>>  };
>> @@ -564,6 +570,8 @@ extern __be32 nfsd4_delegreturn(struct svc_rqst *rqstp,
>>  		struct nfsd4_compound_state *, struct nfsd4_delegreturn *dr);
>>  extern __be32 nfsd4_renew(struct svc_rqst *rqstp,
>>  			  struct nfsd4_compound_state *, clientid_t *clid);
>> +extern __be32 nfsd4_free_stateid(struct svc_rqst *rqstp,
>> +		struct nfsd4_compound_state *, struct nfsd4_free_stateid *free_stateid);
>>  #endif
>>  
>>  /*
>> -- 
>> 1.7.5.1
>>
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