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nfsd4: fix encoding of out-of-space replies

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If nfsd4_check_resp_size() returns an error then we should really be
truncating the reply here, otherwise we may leave extra garbage at the
end of the rpc reply.

Also add a warning to catch any cases where our reply-size estimates may
be wrong in the case of a non-idempotent operation.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
J. Bruce Fields 2014-03-06 20:39:29 -05:00
parent 1802a67894
commit 07d1f80207
3 changed files with 27 additions and 5 deletions
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13
fs/nfsd/nfs4proc.c
View file

@ -1171,9 +1171,7 @@ struct nfsd4_operation {
static struct nfsd4_operation nfsd4_ops[];
#ifdef NFSD_DEBUG
static const char *nfsd4_op_name(unsigned opnum);
#endif
/*
* Enforce NFSv4.1 COMPOUND ordering rules:
@ -1859,14 +1857,21 @@ static struct nfsd4_operation nfsd4_ops[] = {
},
};
#ifdef NFSD_DEBUG
void warn_on_nonidempotent_op(struct nfsd4_op *op)
{
if (OPDESC(op)->op_flags & OP_MODIFIES_SOMETHING) {
pr_err("unable to encode reply to nonidempotent op %d (%s)\n",
op->opnum, nfsd4_op_name(op->opnum));
WARN_ON_ONCE(1);
}
}
static const char *nfsd4_op_name(unsigned opnum)
{
if (opnum < ARRAY_SIZE(nfsd4_ops))
return nfsd4_ops[opnum].op_name;
return "unknown_operation";
}
#endif
#define nfsd4_voidres nfsd4_voidargs
struct nfsd4_voidargs { int dummy; };

17
fs/nfsd/nfs4xdr.c
View file

@ -3637,6 +3637,7 @@ nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op)
{
struct nfs4_stateowner *so = resp->cstate.replay_owner;
__be32 *statp;
nfsd4_enc encoder;
__be32 *p;
RESERVE_SPACE(8);
@ -3648,10 +3649,24 @@ nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op)
goto status;
BUG_ON(op->opnum < 0 || op->opnum >= ARRAY_SIZE(nfsd4_enc_ops) ||
!nfsd4_enc_ops[op->opnum]);
op->status = nfsd4_enc_ops[op->opnum](resp, op->status, &op->u);
encoder = nfsd4_enc_ops[op->opnum];
op->status = encoder(resp, op->status, &op->u);
/* nfsd4_check_resp_size guarantees enough room for error status */
if (!op->status)
op->status = nfsd4_check_resp_size(resp, 0);
if (op->status == nfserr_resource ||
op->status == nfserr_rep_too_big ||
op->status == nfserr_rep_too_big_to_cache) {
/*
* The operation may have already been encoded or
* partially encoded. No op returns anything additional
* in the case of one of these three errors, so we can
* just truncate back to after the status. But it's a
* bug if we had to do this on a non-idempotent op:
*/
warn_on_nonidempotent_op(op);
resp->xdr.p = statp + 1;
}
if (so) {
so->so_replay.rp_status = op->status;
so->so_replay.rp_buflen = (char *)resp->xdr.p

2
fs/nfsd/xdr4.h
View file

@ -536,6 +536,8 @@ static inline bool nfsd4_last_compound_op(struct svc_rqst *rqstp)
return argp->opcnt == resp->opcnt;
}
void warn_on_nonidempotent_op(struct nfsd4_op *op);
#define NFS4_SVC_XDRSIZE sizeof(struct nfsd4_compoundargs)
static inline void