[RFC PATCH v2 04/11] NFSD: prepare to support SETACL nfs4_acl passthru

Mike Snitzer
2026-02-24T19:24:45Z

Use a separate xdr_buf and xdr_stream in both nfsd4_decode_acl() and
nfsd4_decode_nfsace4().

This prepares for nfsd4_decode_acl() to save off the xdr_buf
associated with the ACL payload so that deferred decode is possible
when nfs4_acl passthru is needed (in next commit).

Signed-off-by: Mike Snitzer <snitzer@hammerspace.com>
---
fs/nfsd/nfs4xdr.c | 57 ++++++++++++++++++++++++++++++-----------------
1 file changed, 37 insertions(+), 20 deletions(-)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index e7793c53d214..464c301d6655 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -288,31 +288,32 @@ nfsd4_decode_bitmap4(struct nfsd4_compoundargs *argp, u32 *bmval, u32 bmlen)
}

static __be32
-nfsd4_decode_nfsace4(struct nfsd4_compoundargs *argp, struct nfs4_ace *ace)
+nfsd4_decode_nfsace4(struct xdr_stream *xdr, struct svc_rqst *rqstp,
+ struct nfs4_ace *ace)
{
__be32 *p, status;
u32 length;

- if (xdr_stream_decode_u32(argp->xdr, &ace->type) < 0)
+ if (xdr_stream_decode_u32(xdr, &ace->type) < 0)
return nfserr_bad_xdr;
- if (xdr_stream_decode_u32(argp->xdr, &ace->flag) < 0)
+ if (xdr_stream_decode_u32(xdr, &ace->flag) < 0)
return nfserr_bad_xdr;
- if (xdr_stream_decode_u32(argp->xdr, &ace->access_mask) < 0)
+ if (xdr_stream_decode_u32(xdr, &ace->access_mask) < 0)
return nfserr_bad_xdr;

- if (xdr_stream_decode_u32(argp->xdr, &length) < 0)
+ if (xdr_stream_decode_u32(xdr, &length) < 0)
return nfserr_bad_xdr;
- p = xdr_inline_decode(argp->xdr, length);
+ p = xdr_inline_decode(xdr, length);
if (!p)
return nfserr_bad_xdr;
ace->whotype = nfs4_acl_get_whotype((char *)p, length);
if (ace->whotype != NFS4_ACL_WHO_NAMED)
status = nfs_ok;
else if (ace->flag & NFS4_ACE_IDENTIFIER_GROUP)
- status = nfsd_map_name_to_gid(argp->rqstp,
+ status = nfsd_map_name_to_gid(rqstp,
(char *)p, length, &ace->who_gid);
else
- status = nfsd_map_name_to_uid(argp->rqstp,
+ status = nfsd_map_name_to_uid(rqstp,
(char *)p, length, &ace->who_uid);

return status;
@@ -320,35 +321,51 @@ nfsd4_decode_nfsace4(struct nfsd4_compoundargs *argp, struct nfs4_ace *ace)

/* A counted array of nfsace4's */
static noinline __be32
-nfsd4_decode_acl(struct nfsd4_compoundargs *argp, struct nfs4_acl **acl)
+nfsd4_decode_acl(struct nfsd4_compoundargs *argp, struct nfs4_acl **acl,
+ u32 acl_len)
{
+
+ struct xdr_buf payload;
+ struct xdr_stream xdr;
struct nfs4_ace *ace;
- __be32 status;
+ __be32 status = nfs_ok;
u32 count;

- if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
+ if (!xdr_stream_subsegment(argp->xdr, &payload, acl_len))
return nfserr_bad_xdr;

- if (count > xdr_stream_remaining(argp->xdr) / 20)
+ xdr_init_decode(&xdr, &payload, payload.head[0].iov_base, NULL);
+
+ if (xdr_stream_decode_u32(&xdr, &count) < 0) {
+ status = nfserr_bad_xdr;
+ goto out;
+ }
+
+ if (count > xdr_stream_remaining(&xdr) / 20) {
/*
* Even with 4-byte names there wouldn't be
* space for that many aces; something fishy is
* going on:
*/
- return nfserr_fbig;
+ status = nfserr_fbig;
+ goto out;
+ }

*acl = svcxdr_tmpalloc(argp, nfs4_acl_bytes(count));
- if (*acl == NULL)
- return nfserr_jukebox;
+ if (*acl == NULL) {
+ status = nfserr_jukebox;
+ goto out;
+ }

(*acl)->naces = count;
for (ace = (*acl)->aces; ace < (*acl)->aces + count; ace++) {
- status = nfsd4_decode_nfsace4(argp, ace);
+ status = nfsd4_decode_nfsace4(&xdr, argp->rqstp, ace);
if (status)
- return status;
+ goto out;
}
-
- return nfs_ok;
+out:
+ xdr_finish_decode(&xdr);
+ return status;
}

static noinline __be32
@@ -514,7 +531,7 @@ nfsd4_decode_fattr4(struct nfsd4_compoundargs *argp, u32 *bmval, u32 bmlen,
iattr->ia_valid |= ATTR_SIZE;
}
if (bmval[0] & FATTR4_WORD0_ACL) {
- status = nfsd4_decode_acl(argp, acl);
+ status = nfsd4_decode_acl(argp, acl, attrlist4_count);
if (status)
return status;
} else
--
2.44.0