From: Chuck Lever <chuck.lever@xxxxxxxxxx>
[ Upstream commit 9ed666eba4e0a2bb8ffaa3739d830b64d4f2aaad ]
Currently, when NFSD handles an asynchronous COPY, it returns a
zero write verifier, relying on the subsequent CB_OFFLOAD callback
to pass the write verifier and a stable_how4 value to the client.
However, if the CB_OFFLOAD never arrives at the client (for example,
if a network partition occurs just as the server sends the
CB_OFFLOAD operation), the client will never receive this verifier.
Thus, if the client sends a follow-up COMMIT, there is no way for
the client to assess the COMMIT result.
The usual recovery for a missing CB_OFFLOAD is for the client to
send an OFFLOAD_STATUS operation, but that operation does not carry
a write verifier in its result. Neither does it carry a stable_how4
value, so the client /must/ send a COMMIT in this case -- which will
always fail because currently there's still no write verifier in the
COPY result.
Thus the server needs to return a normal write verifier in its COPY
result even if the COPY operation is to be performed asynchronously.
If the server recognizes the callback stateid in subsequent
OFFLOAD_STATUS operations, then obviously it has not restarted, and
the write verifier the client received in the COPY result is still
valid and can be used to assess a COMMIT of the copied data, if one
is needed.
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
[ cel: adjusted to apply to origin/linux-5.15.y ]
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
fs/nfsd/nfs4proc.c | 25 +++++++++----------------
1 file changed, 9 insertions(+), 16 deletions(-)
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 2b1fcf5b6bf8..08d90e0e8fae 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -718,15 +718,6 @@ nfsd4_access(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
&access->ac_supported);
}
-static void gen_boot_verifier(nfs4_verifier *verifier, struct net *net)
-{
- __be32 *verf = (__be32 *)verifier->data;
-
- BUILD_BUG_ON(2*sizeof(*verf) != sizeof(verifier->data));
-
- nfsd_copy_write_verifier(verf, net_generic(net, nfsd_net_id));
-}
-
static __be32
nfsd4_commit(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
union nfsd4_op_u *u)
@@ -1594,7 +1585,6 @@ static void nfsd4_init_copy_res(struct nfsd4_copy *copy, bool sync)
test_bit(NFSD4_COPY_F_COMMITTED, ©->cp_flags) ?
NFS_FILE_SYNC : NFS_UNSTABLE;
nfsd4_copy_set_sync(copy, sync);
- gen_boot_verifier(©->cp_res.wr_verifier, copy->cp_clp->net);
}
static ssize_t _nfsd_copy_file_range(struct nfsd4_copy *copy,
@@ -1765,9 +1755,14 @@ static __be32
nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
union nfsd4_op_u *u)
{
- struct nfsd4_copy *copy = &u->copy;
- __be32 status;
+ struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
struct nfsd4_copy *async_copy = NULL;
+ struct nfsd4_copy *copy = &u->copy;
+ struct nfsd42_write_res *result;
+ __be32 status;
+
+ result = ©->cp_res;
+ nfsd_copy_write_verifier((__be32 *)&result->wr_verifier.data, nn);
copy->cp_clp = cstate->clp;
if (nfsd4_ssc_is_inter(copy)) {
@@ -1787,8 +1782,6 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
memcpy(©->fh, &cstate->current_fh.fh_handle,
sizeof(struct knfsd_fh));
if (nfsd4_copy_is_async(copy)) {
- struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
-
status = nfserrno(-ENOMEM);
async_copy = kzalloc(sizeof(struct nfsd4_copy), GFP_KERNEL);
if (!async_copy)
@@ -1800,8 +1793,8 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
goto out_err;
if (!nfs4_init_copy_state(nn, copy))
goto out_err;
- memcpy(©->cp_res.cb_stateid, ©->cp_stateid.cs_stid,
- sizeof(copy->cp_res.cb_stateid));
+ memcpy(&result->cb_stateid, ©->cp_stateid.cs_stid,
+ sizeof(result->cb_stateid));
dup_copy_fields(copy, async_copy);
async_copy->copy_task = kthread_create(nfsd4_do_async_copy,
async_copy, "%s", "copy thread");
--
2.47.0
