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nfsd4: more precise nfsd4_max_reply

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It will turn out to be useful to have a more accurate estimate of reply
size; so, piggyback on the existing op reply-size estimators.

Also move nfsd4_max_reply to nfs4proc.c to get easier access to struct
nfsd4_operation and friends.  (Thanks to Christoph Hellwig for pointing
out that simplification.)

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
J. Bruce Fields
2014-03-11 15:39:13 -04:00
parent 8c7424cff6
commit 4f0cefbf38
3 changed files with 17 additions and 31 deletions
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35
fs/nfsd/nfs4xdr.c
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@@ -1605,40 +1605,13 @@ nfsd4_opnum_in_range(struct nfsd4_compoundargs *argp, struct nfsd4_op *op)
return true;
}
/*
* Return a rough estimate of the maximum possible reply size. Note the
* estimate includes rpc headers so is meant to be passed to
* svc_reserve, not svc_reserve_auth.
*
* Also note the current compound encoding permits only one operation to
* use pages beyond the first one, so the maximum possible length is the
* maximum over these values, not the sum.
*/
static int nfsd4_max_reply(u32 opnum)
{
switch (opnum) {
case OP_READLINK:
case OP_READDIR:
/*
* Both of these ops take a single page for data and put
* the head and tail in another page:
*/
return 2 * PAGE_SIZE;
case OP_GETATTR:
case OP_READ:
return INT_MAX;
default:
return PAGE_SIZE;
}
}
static __be32
nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
{
DECODE_HEAD;
struct nfsd4_op *op;
bool cachethis = false;
int max_reply = PAGE_SIZE;
int max_reply = 2 * RPC_MAX_AUTH_SIZE + 8; /* opcnt, status */
int i;
READ_BUF(4);
@@ -1647,6 +1620,7 @@ nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
SAVEMEM(argp->tag, argp->taglen);
READ32(argp->minorversion);
READ32(argp->opcnt);
max_reply += 4 + (XDR_QUADLEN(argp->taglen) << 2);
if (argp->taglen > NFSD4_MAX_TAGLEN)
goto xdr_error;
@@ -1684,7 +1658,7 @@ nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
*/
cachethis |= nfsd4_cache_this_op(op);
max_reply = max(max_reply, nfsd4_max_reply(op->opnum));
max_reply += nfsd4_max_reply(argp->rqstp, op);
if (op->status) {
argp->opcnt = i+1;
@@ -1694,8 +1668,7 @@ nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
/* Sessions make the DRC unnecessary: */
if (argp->minorversion)
cachethis = false;
if (max_reply != INT_MAX)
svc_reserve(argp->rqstp, max_reply);
svc_reserve(argp->rqstp, max_reply);
argp->rqstp->rq_cachetype = cachethis ? RC_REPLBUFF : RC_NOCACHE;
DECODE_TAIL;