5.15-stable review patch. If anyone has any objections, please let me know.
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From: Chuck Lever chuck.lever@oracle.com
[ 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@kernel.org [ cel: adjusted to apply to origin/linux-5.15.y ] Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nfsd/nfs4proc.c | 23 ++++++++--------------- 1 file changed, 8 insertions(+), 15 deletions(-)
--- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -718,15 +718,6 @@ nfsd4_access(struct svc_rqst *rqstp, str &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 n 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 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; - struct nfsd4_copy *async_copy = NULL; + + 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, struc 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, struc 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");