[PATCH 11/30] nfsd41: use static buffers for sessions DRC

andros
2009-06-08T18:21:24Z

Change from page based to memory based NFSv4.1 DRC.

We need to allocate memory for the session DRC in the CREATE_SESSION operation
because of the guarantee to the client that the memory resource is available
for caching responses.

In preparation to remove struct nfsd4_cache_entry, add static storage to
struct nfsd4_slot to hold up to NFSD_SLOT_CACH_SIZE of all encoded operation
data past the encoded sequence operation.

The encoded operation processing length is checked prior to the
nfsd4_store_cache_entry call by nfsd4_check_drc_limit. Note that
nfsd4_check_drc_limit() does this check after processing each operation which
is incorrect, it should be done prior to processing.

Signed-off-by: Andy Adamson <andros@netapp.com>
---
fs/nfsd/nfs4state.c | 12 ++++++++++++
fs/nfsd/nfs4xdr.c | 1 +
include/linux/nfsd/state.h | 2 ++
include/linux/nfsd/xdr4.h | 1 +
4 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index cdc2a5e..ab80a38 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1048,6 +1048,7 @@ nfsd4_copy_pages(struct page **topages, struct page **frompages, short count)
void
nfsd4_store_cache_entry(struct nfsd4_compoundres *resp)
{
+ struct nfsd4_slot *slot = resp->cstate.slot;
struct nfsd4_cache_entry *entry = &resp->cstate.slot->sl_cache_entry;
struct svc_rqst *rqstp = resp->rqstp;
struct nfsd4_compoundargs *args = rqstp->rq_argp;
@@ -1072,10 +1073,17 @@ nfsd4_store_cache_entry(struct nfsd4_compoundres *resp)
if (nfsd4_not_cached(resp)) {
entry->ce_resused = 0;
entry->ce_rpchdrlen = 0;
+ slot->sl_datalen = 0;
dprintk("%s Just cache SEQUENCE. ce_cachethis %d\n", __func__,
resp->cstate.slot->sl_cache_entry.ce_cachethis);
return;
}
+ /* Length is checked to be <= se_fmaxresp_cached in
+ * nfsd4_check_drc_limit
+ */
+ slot->sl_datalen = (char *)resp->p - (char *)resp->cstate.datap;
+ memcpy(slot->sl_data, resp->cstate.datap, slot->sl_datalen);
+
entry->ce_resused = rqstp->rq_resused;
if (entry->ce_resused > NFSD_PAGES_PER_SLOT + 1)
entry->ce_resused = NFSD_PAGES_PER_SLOT + 1;
@@ -1123,6 +1131,7 @@ __be32
nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
struct nfsd4_sequence *seq)
{
+ struct nfsd4_slot *slot = resp->cstate.slot;
struct nfsd4_cache_entry *entry = &resp->cstate.slot->sl_cache_entry;
__be32 status;

@@ -1143,6 +1152,9 @@ nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
return nfs_ok;
}

+ /* The sequence operation has been encoded, cstate->datap set. */
+ memcpy(resp->cstate.datap, slot->sl_data, slot->sl_datalen);
+
if (!nfsd41_copy_replay_data(resp, entry)) {
/*
* Not enough room to use the replay rpc header, send the
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 7e6b139..6f7e7b2 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3090,6 +3090,7 @@ nfsd4_encode_sequence(struct nfsd4_compoundres *resp, int nfserr,
WRITE32(0);

ADJUST_ARGS();
+ resp->cstate.datap = p; /* DRC cache data pointer */
return 0;
}

diff --git a/include/linux/nfsd/state.h b/include/linux/nfsd/state.h
index 28ddb32..5319be5 100644
--- a/include/linux/nfsd/state.h
+++ b/include/linux/nfsd/state.h
@@ -120,6 +120,8 @@ struct nfsd4_cache_entry {
struct nfsd4_slot {
bool sl_inuse;
u32 sl_seqid;
+ u32 sl_datalen;
+ char sl_data[NFSD_SLOT_CACHE_SIZE];
struct nfsd4_cache_entry sl_cache_entry;
};

diff --git a/include/linux/nfsd/xdr4.h b/include/linux/nfsd/xdr4.h
index 6e24dbb..9ab9ab6 100644
--- a/include/linux/nfsd/xdr4.h
+++ b/include/linux/nfsd/xdr4.h
@@ -52,6 +52,7 @@ struct nfsd4_compound_state {
struct nfsd4_session *session;
struct nfsd4_slot *slot;
__be32 *statp;
+ __be32 *datap;
size_t iovlen;
u32 minorversion;
u32 status;
--
1.5.4.3