Re: [PATCH v2 16/47] nfsd41: match clientid establishment method

["J. Bruce Fields" <bfields@fieldses.org>]

On Tue, Mar 31, 2009 at 09:59:17AM +0300, Benny Halevy wrote:
> On Mar. 31, 2009, 1:07 +0300, "J. Bruce Fields" <bfields@fieldses.org> wrote:
> > On Sat, Mar 28, 2009 at 11:32:17AM +0300, Benny Halevy wrote:
> >> From: Andy Adamson <andros@netapp.com>
> >>
> >> We need to distinguish between client names provided by NFSv4.0 clients
> >> SETCLIENTID and those provided by NFSv4.1 via EXCHANGE_ID when looking
> >> up the clientid by string.
> >>
> >> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
> >> Signed-off-by: Andy Adamson <andros@netapp.com>
> >> [nfsd41: use boolean values for use_exchange_id argument]
> >> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
> >> ---
> >>  fs/nfsd/nfs4recover.c      |    3 ++-
> >>  fs/nfsd/nfs4state.c        |   41 ++++++++++++++++++++++++++++++-----------
> >>  include/linux/nfsd/state.h |    2 +-
> >>  3 files changed, 33 insertions(+), 13 deletions(-)
> >>
> >> diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
> >> index b11cf8d..3444c00 100644
> >> --- a/fs/nfsd/nfs4recover.c
> >> +++ b/fs/nfsd/nfs4recover.c
> >> @@ -344,7 +344,8 @@ purge_old(struct dentry *parent, struct dentry *child)
> >>  {
> >>  	int status;
> >>  
> >> -	if (nfs4_has_reclaimed_state(child->d_name.name))
> >> +	/* note: we currently use this path only for minorversion 0 */
> >> +	if (nfs4_has_reclaimed_state(child->d_name.name, false))
> >>  		return 0;
> >>  
> >>  	status = nfsd4_clear_clid_dir(parent, child);
> >> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> >> index 09c63ff..0c39376 100644
> >> --- a/fs/nfsd/nfs4state.c
> >> +++ b/fs/nfsd/nfs4state.c
> >> @@ -723,25 +723,44 @@ find_unconfirmed_client(clientid_t *clid)
> >>  	return NULL;
> >>  }
> >>  
> >> +/*
> >> + * Return 1 iff clp's clientid establishment method matches the use_exchange_id
> >> + * parameter. Matching is based on the fact the at least one of the
> >> + * EXCHGID4_FLAG_USE_{NON_PNFS,PNFS_MDS,PNFS_DS} flags must be set for v4.1
> >> + */
> >> +static inline int
> >> +match_clientid_establishment(struct nfs4_client *clp, bool use_exchange_id)
> >> +{
> >> +#if defined(CONFIG_NFSD_V4_1)
> >> +	return (clp->cl_exchange_flags != 0) == (use_exchange_id != false);
> > 
> > This seems a bit baroque; the "!= false" is a no-op, for one thing,
> > isn't it?
> 
> The idea is to efficiently do explicit boolean comparison.
> Without the "!= false" the comparison will fail for
> 1 != use_exchange_id != 0.

use_exchange_id is defined to be boolean.

--b.

> 
> Does this make it any clearer:
> 
> 	if (use_exchange_flags)
> 		return clp->cl_exchange_flags != 0;
> 	return clp->cl_exchange_flags == 0;
> 
> or maybe
> 
> 	bool has_exchange_flags = (clp->cl_exchange_flags != 0);
> 	if (use_exchange_flags)
> 		return has_exchange_flags;
> 	return !has_exchange_flags;
> 
> or a long boolean expression
> 
> 	return ((clp->cl_exchange_flags && use_exchange_id) ||
> 		(!clp->cl_exchange_flags && !use_exchange_id))
> 
> Benny
> 
> > 
> > --b.
> > 
> >> +#else  /* CONFIG_NFSD_V4_1 */
> >> +	return 1;
> >> +#endif /* CONFIG_NFSD_V4_1 */
> >> +}
> >> +
> >>  static struct nfs4_client *
> >> -find_confirmed_client_by_str(const char *dname, unsigned int hashval)
> >> +find_confirmed_client_by_str(const char *dname, unsigned int hashval,
> >> +			     bool use_exchange_id)
> >>  {
> >>  	struct nfs4_client *clp;
> >>  
> >>  	list_for_each_entry(clp, &conf_str_hashtbl[hashval], cl_strhash) {
> >> -		if (same_name(clp->cl_recdir, dname))
> >> +		if (same_name(clp->cl_recdir, dname) &&
> >> +		    match_clientid_establishment(clp, use_exchange_id))
> >>  			return clp;
> >>  	}
> >>  	return NULL;
> >>  }
> >>  
> >>  static struct nfs4_client *
> >> -find_unconfirmed_client_by_str(const char *dname, unsigned int hashval)
> >> +find_unconfirmed_client_by_str(const char *dname, unsigned int hashval,
> >> +			       bool use_exchange_id)
> >>  {
> >>  	struct nfs4_client *clp;
> >>  
> >>  	list_for_each_entry(clp, &unconf_str_hashtbl[hashval], cl_strhash) {
> >> -		if (same_name(clp->cl_recdir, dname))
> >> +		if (same_name(clp->cl_recdir, dname) &&
> >> +		    match_clientid_establishment(clp, use_exchange_id))
> >>  			return clp;
> >>  	}
> >>  	return NULL;
> >> @@ -895,7 +914,7 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
> >>  	nfs4_lock_state();
> >>  	status = nfs_ok;
> >>  
> >> -	conf = find_confirmed_client_by_str(dname, strhashval);
> >> +	conf = find_confirmed_client_by_str(dname, strhashval, true);
> >>  	if (conf) {
> >>  		if (!same_verf(&verf, &conf->cl_verifier)) {
> >>  			/* 18.35.4 case 8 */
> >> @@ -943,7 +962,7 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
> >>  		}
> >>  	}
> >>  
> >> -	unconf  = find_unconfirmed_client_by_str(dname, strhashval);
> >> +	unconf  = find_unconfirmed_client_by_str(dname, strhashval, true);
> >>  	if (unconf) {
> >>  		/*
> >>  		 * Possible retry or client restart.  Per 18.35.4 case 4,
> >> @@ -1041,7 +1060,7 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> >>  	strhashval = clientstr_hashval(dname);
> >>  
> >>  	nfs4_lock_state();
> >> -	conf = find_confirmed_client_by_str(dname, strhashval);
> >> +	conf = find_confirmed_client_by_str(dname, strhashval, false);
> >>  	if (conf) {
> >>  		/* RFC 3530 14.2.33 CASE 0: */
> >>  		status = nfserr_clid_inuse;
> >> @@ -1056,7 +1075,7 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> >>  	 * has a description of SETCLIENTID request processing consisting
> >>  	 * of 5 bullet points, labeled as CASE0 - CASE4 below.
> >>  	 */
> >> -	unconf = find_unconfirmed_client_by_str(dname, strhashval);
> >> +	unconf = find_unconfirmed_client_by_str(dname, strhashval, false);
> >>  	status = nfserr_resource;
> >>  	if (!conf) {
> >>  		/*
> >> @@ -1211,7 +1230,7 @@ nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
> >>  			unsigned int hash =
> >>  				clientstr_hashval(unconf->cl_recdir);
> >>  			conf = find_confirmed_client_by_str(unconf->cl_recdir,
> >> -									hash);
> >> +							    hash, false);
> >>  			if (conf) {
> >>  				nfsd4_remove_clid_dir(conf);
> >>  				expire_client(conf);
> >> @@ -3332,12 +3351,12 @@ alloc_reclaim(void)
> >>  }
> >>  
> >>  int
> >> -nfs4_has_reclaimed_state(const char *name)
> >> +nfs4_has_reclaimed_state(const char *name, bool use_exchange_id)
> >>  {
> >>  	unsigned int strhashval = clientstr_hashval(name);
> >>  	struct nfs4_client *clp;
> >>  
> >> -	clp = find_confirmed_client_by_str(name, strhashval);
> >> +	clp = find_confirmed_client_by_str(name, strhashval, use_exchange_id);
> >>  	return clp ? 1 : 0;
> >>  }
> >>  
> >> diff --git a/include/linux/nfsd/state.h b/include/linux/nfsd/state.h
> >> index 5de36a7..feab6ec 100644
> >> --- a/include/linux/nfsd/state.h
> >> +++ b/include/linux/nfsd/state.h
> >> @@ -331,7 +331,7 @@ extern void nfsd4_init_recdir(char *recdir_name);
> >>  extern int nfsd4_recdir_load(void);
> >>  extern void nfsd4_shutdown_recdir(void);
> >>  extern int nfs4_client_to_reclaim(const char *name);
> >> -extern int nfs4_has_reclaimed_state(const char *name);
> >> +extern int nfs4_has_reclaimed_state(const char *name, bool use_exchange_id);
> >>  extern void nfsd4_recdir_purge_old(void);
> >>  extern int nfsd4_create_clid_dir(struct nfs4_client *clp);
> >>  extern void nfsd4_remove_clid_dir(struct nfs4_client *clp);
> >> -- 
> >> 1.6.2.1
> >>