From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
To ensure ordering of read data with any following operations, turn off
zero copy if the read is not the final operation in the compound.
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
---
fs/nfsd/nfs4proc.c | 11 +++++++++++
fs/nfsd/nfs4state.c | 8 --------
fs/nfsd/xdr4.h | 8 ++++++++
3 files changed, 19 insertions(+), 8 deletions(-)
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index bd67f4d..2a2d9b0 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -692,6 +692,17 @@ nfsd4_read(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
if (read->rd_offset >= OFFSET_MAX)
return nfserr_inval;
+ /*
+ * If we do a zero copy read, then a client will see read data
+ * that reflects the state of the file *after* performing the
+ * following compound.
+ *
+ * To ensure proper ordering, we therefore turn off zero copy if
+ * the client wants us to do more in this compound:
+ */
+ if (!nfsd4_last_compound_op(rqstp))
+ rqstp->rq_splice_ok = false;
+
nfs4_lock_state();
/* check stateid */
if ((status = nfs4_preprocess_stateid_op(SVC_NET(rqstp),
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 8e25551..8e127b3 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1855,14 +1855,6 @@ out_free_session:
goto out;
}
-static bool nfsd4_last_compound_op(struct svc_rqst *rqstp)
-{
- struct nfsd4_compoundres *resp = rqstp->rq_resp;
- struct nfsd4_compoundargs *argp = rqstp->rq_argp;
-
- return argp->opcnt == resp->opcnt;
-}
-
static __be32 nfsd4_map_bcts_dir(u32 *dir)
{
switch (*dir) {
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 331f8a3..0889bfb 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -528,6 +528,14 @@ static inline bool nfsd4_not_cached(struct nfsd4_compoundres *resp)
|| nfsd4_is_solo_sequence(resp);
}
+static inline bool nfsd4_last_compound_op(struct svc_rqst *rqstp)
+{
+ struct nfsd4_compoundres *resp = rqstp->rq_resp;
+ struct nfsd4_compoundargs *argp = rqstp->rq_argp;
+
+ return argp->opcnt == resp->opcnt;
+}
+
#define NFS4_SVC_XDRSIZE sizeof(struct nfsd4_compoundargs)
static inline void
--
1.7.9.5
--
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