NFS/NFSD/SUNRPC: replace generic creds with 'struct cred'.

SUNRPC has two sorts of credentials, both of which appear as
"struct rpc_cred".
There are "generic credentials" which are supplied by clients
such as NFS and passed in 'struct rpc_message' to indicate
which user should be used to authorize the request, and there
are low-level credentials such as AUTH_NULL, AUTH_UNIX, AUTH_GSS
which describe the credential to be sent over the wires.

This patch replaces all the generic credentials by 'struct cred'
pointers - the credential structure used throughout Linux.

For machine credentials, there is a special 'struct cred *' pointer
which is statically allocated and recognized where needed as
having a special meaning.  A look-up of a low-level cred will
map this to a machine credential.

Signed-off-by: NeilBrown <neilb@suse.com>
Acked-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

3 files changed, 23 insertions, 34 deletions

diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index 1d1c5d127928..63abe705f4ca 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -224,16 +224,14 @@ static struct nfs4_ff_layout_mirror *ff_layout_alloc_mirror(gfp_t gfp_flags)
 
 static void ff_layout_free_mirror(struct nfs4_ff_layout_mirror *mirror)
 {
-	struct rpc_cred	*cred;
+	const struct cred	*cred;
 
 	ff_layout_remove_mirror(mirror);
 	kfree(mirror->fh_versions);
 	cred = rcu_access_pointer(mirror->ro_cred);
-	if (cred)
-		put_rpccred(cred);
+	put_cred(cred);
 	cred = rcu_access_pointer(mirror->rw_cred);
-	if (cred)
-		put_rpccred(cred);
+	put_cred(cred);
 	nfs4_ff_layout_put_deviceid(mirror->mirror_ds);
 	kfree(mirror);
 }
@@ -411,9 +409,8 @@ ff_layout_alloc_lseg(struct pnfs_layout_hdr *lh,
 
 	for (i = 0; i < fls->mirror_array_cnt; i++) {
 		struct nfs4_ff_layout_mirror *mirror;
-		struct auth_cred acred = {};
-		struct rpc_cred	__rcu *cred;
 		struct cred *kcred;
+		const struct cred *cred;
 		kuid_t uid;
 		kgid_t gid;
 		u32 ds_count, fh_count, id;
@@ -504,15 +501,7 @@ ff_layout_alloc_lseg(struct pnfs_layout_hdr *lh,
 			goto out_err_free;
 		kcred->fsuid = uid;
 		kcred->fsgid = gid;
-		acred.cred = kcred;
-
-		/* find the cred for it */
-		rcu_assign_pointer(cred, rpc_lookup_generic_cred(&acred, 0, gfp_flags));
-		put_cred(kcred);
-		if (IS_ERR(cred)) {
-			rc = PTR_ERR(cred);
-			goto out_err_free;
-		}
+		cred = kcred;
 
 		if (lgr->range.iomode == IOMODE_READ)
 			rcu_assign_pointer(fls->mirror_array[i]->ro_cred, cred);
@@ -1714,7 +1703,7 @@ ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
 	struct pnfs_layout_segment *lseg = hdr->lseg;
 	struct nfs4_pnfs_ds *ds;
 	struct rpc_clnt *ds_clnt;
-	struct rpc_cred *ds_cred;
+	const struct cred *ds_cred;
 	loff_t offset = hdr->args.offset;
 	u32 idx = hdr->pgio_mirror_idx;
 	int vers;
@@ -1765,7 +1754,7 @@ ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
 			  vers == 3 ? &ff_layout_read_call_ops_v3 :
 				      &ff_layout_read_call_ops_v4,
 			  0, RPC_TASK_SOFTCONN);
-	put_rpccred(ds_cred);
+	put_cred(ds_cred);
 	return PNFS_ATTEMPTED;
 
 out_failed:
@@ -1781,7 +1770,7 @@ ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
 	struct pnfs_layout_segment *lseg = hdr->lseg;
 	struct nfs4_pnfs_ds *ds;
 	struct rpc_clnt *ds_clnt;
-	struct rpc_cred *ds_cred;
+	const struct cred *ds_cred;
 	loff_t offset = hdr->args.offset;
 	int vers;
 	struct nfs_fh *fh;
@@ -1830,7 +1819,7 @@ ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
 			  vers == 3 ? &ff_layout_write_call_ops_v3 :
 				      &ff_layout_write_call_ops_v4,
 			  sync, RPC_TASK_SOFTCONN);
-	put_rpccred(ds_cred);
+	put_cred(ds_cred);
 	return PNFS_ATTEMPTED;
 
 out_failed:
@@ -1860,7 +1849,7 @@ static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
 	struct pnfs_layout_segment *lseg = data->lseg;
 	struct nfs4_pnfs_ds *ds;
 	struct rpc_clnt *ds_clnt;
-	struct rpc_cred *ds_cred;
+	const struct cred *ds_cred;
 	u32 idx;
 	int vers, ret;
 	struct nfs_fh *fh;
@@ -1900,7 +1889,7 @@ static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
 				   vers == 3 ? &ff_layout_commit_call_ops_v3 :
 					       &ff_layout_commit_call_ops_v4,
 				   how, RPC_TASK_SOFTCONN);
-	put_rpccred(ds_cred);
+	put_cred(ds_cred);
 	return ret;
 out_err:
 	pnfs_generic_prepare_to_resend_writes(data);
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.h b/fs/nfs/flexfilelayout/flexfilelayout.h
index de50a342d5a5..c2626bad466b 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.h
+++ b/fs/nfs/flexfilelayout/flexfilelayout.h
@@ -81,8 +81,8 @@ struct nfs4_ff_layout_mirror {
 	u32				fh_versions_cnt;
 	struct nfs_fh			*fh_versions;
 	nfs4_stateid			stateid;
-	struct rpc_cred	__rcu		*ro_cred;
-	struct rpc_cred	__rcu		*rw_cred;
+	const struct cred __rcu		*ro_cred;
+	const struct cred __rcu		*rw_cred;
 	refcount_t			ref;
 	spinlock_t			lock;
 	unsigned long			flags;
@@ -229,8 +229,8 @@ nfs4_ff_find_or_create_ds_client(struct pnfs_layout_segment *lseg,
 				 u32 ds_idx,
 				 struct nfs_client *ds_clp,
 				 struct inode *inode);
-struct rpc_cred *ff_layout_get_ds_cred(struct pnfs_layout_segment *lseg,
-				       u32 ds_idx, struct rpc_cred *mdscred);
+const struct cred *ff_layout_get_ds_cred(struct pnfs_layout_segment *lseg,
+				       u32 ds_idx, const struct cred *mdscred);
 bool ff_layout_avoid_mds_available_ds(struct pnfs_layout_segment *lseg);
 bool ff_layout_avoid_read_on_rw(struct pnfs_layout_segment *lseg);
 
diff --git a/fs/nfs/flexfilelayout/flexfilelayoutdev.c b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
index d23347389626..11766a74216d 100644
--- a/fs/nfs/flexfilelayout/flexfilelayoutdev.c
+++ b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
@@ -330,10 +330,10 @@ int ff_layout_track_ds_error(struct nfs4_flexfile_layout *flo,
 	return 0;
 }
 
-static struct rpc_cred *
+static const struct cred *
 ff_layout_get_mirror_cred(struct nfs4_ff_layout_mirror *mirror, u32 iomode)
 {
-	struct rpc_cred *cred, __rcu **pcred;
+	const struct cred *cred, __rcu **pcred;
 
 	if (iomode == IOMODE_READ)
 		pcred = &mirror->ro_cred;
@@ -346,7 +346,7 @@ ff_layout_get_mirror_cred(struct nfs4_ff_layout_mirror *mirror, u32 iomode)
 		if (!cred)
 			break;
 
-		cred = get_rpccred_rcu(cred);
+		cred = get_cred_rcu(cred);
 	} while(!cred);
 	rcu_read_unlock();
 	return cred;
@@ -465,19 +465,19 @@ out:
 	return ds;
 }
 
-struct rpc_cred *
+const struct cred *
 ff_layout_get_ds_cred(struct pnfs_layout_segment *lseg, u32 ds_idx,
-		      struct rpc_cred *mdscred)
+		      const struct cred *mdscred)
 {
 	struct nfs4_ff_layout_mirror *mirror = FF_LAYOUT_COMP(lseg, ds_idx);
-	struct rpc_cred *cred;
+	const struct cred *cred;
 
 	if (mirror && !mirror->mirror_ds->ds_versions[0].tightly_coupled) {
 		cred = ff_layout_get_mirror_cred(mirror, lseg->pls_range.iomode);
 		if (!cred)
-			cred = get_rpccred(mdscred);
+			cred = get_cred(mdscred);
 	} else {
-		cred = get_rpccred(mdscred);
+		cred = get_cred(mdscred);
 	}
 	return cred;
 }