[PATCH 5/4] nfsd4: simplify xdr encoding of nfsv4 names

J. Bruce Fields
2014-01-08T17:16:21Z

We can simplify the idmapping code if it does its own encoding and
returns nfs errors.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
fs/nfsd/acl.h | 2 +-
fs/nfsd/idmap.h | 4 ++--
fs/nfsd/nfs4acl.c | 20 +++++++++++++-------
fs/nfsd/nfs4idmap.c | 50 ++++++++++++++++++++++++++++++++-----------------
fs/nfsd/nfs4xdr.c | 52 ++++++---------------------------------------------
5 files changed, 55 insertions(+), 73 deletions(-)

On Tue, Jan 07, 2014 at 04:04:30PM -0500, J. Bruce Fields wrote:
> These are just some minor bits of cleanup I'm queueing for 3.14.

And one more.--b.

diff --git a/fs/nfsd/acl.h b/fs/nfsd/acl.h
index 8b186a4..5b7bf21 100644
--- a/fs/nfsd/acl.h
+++ b/fs/nfsd/acl.h
@@ -43,7 +43,7 @@

struct nfs4_acl *nfs4_acl_new(int);
int nfs4_acl_get_whotype(char *, u32);
-int nfs4_acl_write_who(int who, char *p);
+int nfs4_acl_write_who(int who, __be32 **p, int *len);

#define NFS4_ACL_TYPE_DEFAULT 0x01
#define NFS4_ACL_DIR 0x02
diff --git a/fs/nfsd/idmap.h b/fs/nfsd/idmap.h
index bf95f6b..66e58db 100644
--- a/fs/nfsd/idmap.h
+++ b/fs/nfsd/idmap.h
@@ -56,7 +56,7 @@ static inline void nfsd_idmap_shutdown(struct net *net)

__be32 nfsd_map_name_to_uid(struct svc_rqst *, const char *, size_t, kuid_t *);
__be32 nfsd_map_name_to_gid(struct svc_rqst *, const char *, size_t, kgid_t *);
-int nfsd_map_uid_to_name(struct svc_rqst *, kuid_t, char *);
-int nfsd_map_gid_to_name(struct svc_rqst *, kgid_t, char *);
+__be32 nfsd4_encode_user(struct svc_rqst *, kuid_t, __be32 **, int *);
+__be32 nfsd4_encode_group(struct svc_rqst *, kgid_t, __be32 **, int *);

#endif /* LINUX_NFSD_IDMAP_H */
diff --git a/fs/nfsd/nfs4acl.c b/fs/nfsd/nfs4acl.c
index 8a50b3c..eea24c9 100644
--- a/fs/nfsd/nfs4acl.c
+++ b/fs/nfsd/nfs4acl.c
@@ -37,6 +37,7 @@
#include <linux/slab.h>
#include <linux/nfs_fs.h>
#include <linux/export.h>
+#include "nfsd.h"
#include "acl.h"

@@ -848,18 +849,23 @@ nfs4_acl_get_whotype(char *p, u32 len)
return NFS4_ACL_WHO_NAMED;
}

-int
-nfs4_acl_write_who(int who, char *p)
+__be32 nfs4_acl_write_who(int who, __be32 **p, int *len)
{
int i;
+ int bytes;

for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
- if (s2t_map[i].type == who) {
- memcpy(p, s2t_map[i].string, s2t_map[i].stringlen);
- return s2t_map[i].stringlen;
- }
+ if (s2t_map[i].type != who)
+ continue;
+ bytes = 4 + (XDR_QUADLEN(s2t_map[i].stringlen) << 2);
+ if (bytes > *len)
+ return nfserr_resource;
+ *p = xdr_encode_opaque(*p, s2t_map[i].string,
+ s2t_map[i].stringlen);
+ *len -= bytes;
+ return 0;
}
- BUG();
+ WARN_ON_ONCE(1);
return -1;
}

diff --git a/fs/nfsd/nfs4idmap.c b/fs/nfsd/nfs4idmap.c
index 4832fd8..c0dfde6 100644
--- a/fs/nfsd/nfs4idmap.c
+++ b/fs/nfsd/nfs4idmap.c
@@ -551,27 +551,46 @@ idmap_name_to_id(struct svc_rqst *rqstp, int type, const char *name, u32 namelen
return 0;
}

-static int
-idmap_id_to_name(struct svc_rqst *rqstp, int type, u32 id, char *name)
+static __be32 encode_ascii_id(u32 id, __be32 **p, int *buflen)
+{
+ char buf[11];
+ int len;
+ int bytes;
+
+ len = sprintf(buf, "%u", id);
+ bytes = 4 + (XDR_QUADLEN(len) << 2);
+ if (bytes > *buflen)
+ return nfserr_resource;
+ *p = xdr_encode_opaque(*p, buf, len);
+ *buflen -= bytes;
+ return 0;
+}
+
+static __be32 idmap_id_to_name(struct svc_rqst *rqstp, int type, u32 id, __be32 **p, int *buflen)
{
struct ent *item, key = {
.id = id,
.type = type,
};
int ret;
+ int bytes;
struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);

strlcpy(key.authname, rqst_authname(rqstp), sizeof(key.authname));
ret = idmap_lookup(rqstp, idtoname_lookup, &key, nn->idtoname_cache, &item);
if (ret == -ENOENT)
- return sprintf(name, "%u", id);
+ return encode_ascii_id(id, p, buflen);
if (ret)
- return ret;
+ return nfserrno(ret);
ret = strlen(item->name);
- BUG_ON(ret > IDMAP_NAMESZ);
- memcpy(name, item->name, ret);
+ WARN_ON_ONCE(ret > IDMAP_NAMESZ);
+ bytes = 4 + (XDR_QUADLEN(ret) << 2);
+ if (bytes > *buflen)
+ return nfserr_resource;
+ *p = xdr_encode_opaque(*p, item->name, ret);
+ *buflen -= bytes;
cache_put(&item->h, nn->idtoname_cache);
- return ret;
+ return 0;
}

static bool
@@ -603,12 +622,11 @@ do_name_to_id(struct svc_rqst *rqstp, int type, const char *name, u32 namelen, u
return idmap_name_to_id(rqstp, type, name, namelen, id);
}

-static int
-do_id_to_name(struct svc_rqst *rqstp, int type, u32 id, char *name)
+static __be32 encode_name_from_id(struct svc_rqst *rqstp, int type, u32 id, __be32 **p, int *buflen)
{
if (nfs4_disable_idmapping && rqstp->rq_cred.cr_flavor < RPC_AUTH_GSS)
- return sprintf(name, "%u", id);
- return idmap_id_to_name(rqstp, type, id, name);
+ return encode_ascii_id(id, p, buflen);
+ return idmap_id_to_name(rqstp, type, id, p, buflen);
}

__be32
@@ -637,16 +655,14 @@ nfsd_map_name_to_gid(struct svc_rqst *rqstp, const char *name, size_t namelen,
return status;
}

-int
-nfsd_map_uid_to_name(struct svc_rqst *rqstp, kuid_t uid, char *name)
+__be32 nfsd4_encode_user(struct svc_rqst *rqstp, kuid_t uid, __be32 **p, int *buflen)
{
u32 id = from_kuid(&init_user_ns, uid);
- return do_id_to_name(rqstp, IDMAP_TYPE_USER, id, name);
+ return encode_name_from_id(rqstp, IDMAP_TYPE_USER, id, p, buflen);
}

-int
-nfsd_map_gid_to_name(struct svc_rqst *rqstp, kgid_t gid, char *name)
+__be32 nfsd4_encode_group(struct svc_rqst *rqstp, kgid_t gid, __be32 **p, int *buflen)
{
u32 id = from_kgid(&init_user_ns, gid);
- return do_id_to_name(rqstp, IDMAP_TYPE_GROUP, id, name);
+ return encode_name_from_id(rqstp, IDMAP_TYPE_GROUP, id, p, buflen);
}
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 67b4496..8198ecf 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1965,56 +1965,16 @@ static u32 nfs4_file_type(umode_t mode)
};
}

-static __be32
-nfsd4_encode_name(struct svc_rqst *rqstp, int whotype, kuid_t uid, kgid_t gid,
- __be32 **p, int *buflen)
-{
- int status;
-
- if (*buflen < (XDR_QUADLEN(IDMAP_NAMESZ) << 2) + 4)
- return nfserr_resource;
- if (whotype != NFS4_ACL_WHO_NAMED)
- status = nfs4_acl_write_who(whotype, (u8 *)(*p + 1));
- else if (gid_valid(gid))
- status = nfsd_map_gid_to_name(rqstp, gid, (u8 *)(*p + 1));
- else
- status = nfsd_map_uid_to_name(rqstp, uid, (u8 *)(*p + 1));
- if (status < 0)
- return nfserrno(status);
- *p = xdr_encode_opaque(*p, NULL, status);
- *buflen -= (XDR_QUADLEN(status) << 2) + 4;
- BUG_ON(*buflen < 0);
- return 0;
-}
-
-static inline __be32
-nfsd4_encode_user(struct svc_rqst *rqstp, kuid_t user, __be32 **p, int *buflen)
-{
- return nfsd4_encode_name(rqstp, NFS4_ACL_WHO_NAMED, user, INVALID_GID,
- p, buflen);
-}
-
-static inline __be32
-nfsd4_encode_group(struct svc_rqst *rqstp, kgid_t group, __be32 **p, int *buflen)
-{
- return nfsd4_encode_name(rqstp, NFS4_ACL_WHO_NAMED, INVALID_UID, group,
- p, buflen);
-}
-
static inline __be32
nfsd4_encode_aclname(struct svc_rqst *rqstp, struct nfs4_ace *ace,
__be32 **p, int *buflen)
{
- kuid_t uid = INVALID_UID;
- kgid_t gid = INVALID_GID;
-
- if (ace->whotype == NFS4_ACL_WHO_NAMED) {
- if (ace->flag & NFS4_ACE_IDENTIFIER_GROUP)
- gid = ace->who_gid;
- else
- uid = ace->who_uid;
- }
- return nfsd4_encode_name(rqstp, ace->whotype, uid, gid, p, buflen);
+ if (ace->whotype != NFS4_ACL_WHO_NAMED)
+ return nfs4_acl_write_who(ace->whotype, p, buflen);
+ else if (ace->flag & NFS4_ACE_IDENTIFIER_GROUP)
+ return nfsd4_encode_group(rqstp, ace->who_gid, p, buflen);
+ else
+ return nfsd4_encode_user(rqstp, ace->who_uid, p, buflen);
}

#define WORD0_ABSENT_FS_ATTRS (FATTR4_WORD0_FS_LOCATIONS | FATTR4_WORD0_FSID | \
--
1.7.9.5