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nfsd4: disable zero-copy on non-final read ops

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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>
This commit is contained in:
J. Bruce Fields 2012-12-04 18:03:46 -05:00
parent 3a28e33111
commit 9b3234b922
3 changed files with 19 additions and 8 deletions
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11
fs/nfsd/nfs4proc.c
View File

@ -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),

8
fs/nfsd/nfs4state.c
View File

@ -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) {

8
fs/nfsd/xdr4.h
View File

@ -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