Allow NFSv4 client to use write delegation stateid for READ operation.
Per RFC 8881 section 9.1.2. Use of the Stateid and Locking.
Signed-off-by: Dai Ngo <dai.ngo@xxxxxxxxxx>
---
fs/nfsd/nfs4proc.c | 16 ++++++++++++++--
fs/nfsd/nfs4xdr.c | 9 +++++++++
fs/nfsd/xdr4.h | 2 ++
3 files changed, 25 insertions(+), 2 deletions(-)
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 5ae670807449..3fa66cb38780 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -942,8 +942,18 @@ nfsd4_read(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
/* check stateid */
status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
&read->rd_stateid, RD_STATE,
- &read->rd_nf, NULL);
-
+ &read->rd_nf, &read->rd_wd_stid);
+ /*
+ * rd_wd_stid is needed for nfsd4_encode_read to allow write
+ * delegation stateid used for read. Its refcount is decremented
+ * by nfsd4_read_release when read is done.
+ */
+ if (!status && (read->rd_wd_stid->sc_type != NFS4_DELEG_STID ||
+ delegstateid(read->rd_wd_stid)->dl_type !=
+ NFS4_OPEN_DELEGATE_WRITE)) {
+ nfs4_put_stid(read->rd_wd_stid);
+ read->rd_wd_stid = NULL;
+ }
read->rd_rqstp = rqstp;
read->rd_fhp = &cstate->current_fh;
return status;
@@ -953,6 +963,8 @@ nfsd4_read(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
static void
nfsd4_read_release(union nfsd4_op_u *u)
{
+ if (u->read.rd_wd_stid)
+ nfs4_put_stid(u->read.rd_wd_stid);
if (u->read.rd_nf)
nfsd_file_put(u->read.rd_nf);
trace_nfsd_read_done(u->read.rd_rqstp, u->read.rd_fhp,
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 76db2fe29624..e0640b31d041 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -4120,6 +4120,7 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
struct file *file;
int starting_len = xdr->buf->len;
__be32 *p;
+ fmode_t o_fmode = 0;
if (nfserr)
return nfserr;
@@ -4139,10 +4140,18 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
maxcount = min_t(unsigned long, read->rd_length,
(xdr->buf->buflen - xdr->buf->len));
+ if (read->rd_wd_stid) {
+ /* allow READ using write delegation stateid */
+ o_fmode = file->f_mode;
+ file->f_mode |= FMODE_READ;
+ }
if (file->f_op->splice_read && splice_ok)
nfserr = nfsd4_encode_splice_read(resp, read, file, maxcount);
else
nfserr = nfsd4_encode_readv(resp, read, file, maxcount);
+ if (o_fmode)
+ file->f_mode = o_fmode;
+
if (nfserr) {
xdr_truncate_encode(xdr, starting_len);
return nfserr;
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 510978e602da..3ccc40f9274a 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -307,6 +307,8 @@ struct nfsd4_read {
struct svc_rqst *rd_rqstp; /* response */
struct svc_fh *rd_fhp; /* response */
u32 rd_eof; /* response */
+
+ struct nfs4_stid *rd_wd_stid; /* internal */
};
struct nfsd4_readdir {
--
2.39.3
