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authorJ. Bruce Fields <bfields@redhat.com>2012-12-04 18:03:46 -0500
committerJ. Bruce Fields <bfields@redhat.com>2012-12-17 16:02:41 -0500
commit9b3234b9220aae5387b60bc35a424ab6748b2b59 (patch)
treeeeaf7761a957cd3acdd6c55a91587b28998d0bd9 /fs/nfsd/nfs4proc.c
parent3a28e331115be5130fe061e6b4183b29385116a6 (diff)
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op-kernel-dev-9b3234b9220aae5387b60bc35a424ab6748b2b59.tar.gz
nfsd4: disable zero-copy on non-final read ops
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@redhat.com>
Diffstat (limited to 'fs/nfsd/nfs4proc.c')
-rw-r--r--fs/nfsd/nfs4proc.c11
1 files changed, 11 insertions, 0 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),
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