From: Chuck Lever <chuck.lever@xxxxxxxxxx> We've found that there are cases where a transport disconnection results in the loss of callback RPCs. NFS servers typically do not retransmit callback operations after a disconnect. This can be a problem for the Linux NFS client's implementation of asynchronous COPY, which waits indefinitely for a CB_OFFLOAD callback. If a transport disconnect occurs while an async COPY is running, there's a good chance the client will never get the matching CB_OFFLOAD. Fix this by implementing the OFFLOAD_STATUS operation so that the Linux NFS client can probe the NFS server if it doesn't see a CB_OFFLOAD in a reasonable amount of time. This patch implements a simplistic check. As future work, the client might also be able to detect whether there is no forward progress on the request asynchronous COPY operation, and CANCEL it. Suggested-by: Olga Kornievskaia <kolga@xxxxxxxxxx> Link: https://bugzilla.kernel.org/show_bug.cgi?id=218735 Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> --- fs/nfs/nfs42proc.c | 100 +++++++++++++++++++++++++++++++++++--- fs/nfs/nfs4trace.h | 1 + include/linux/nfs_fs_sb.h | 1 + 3 files changed, 96 insertions(+), 6 deletions(-) diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c index 7656d7c103fa..224fb3b8696a 100644 --- a/fs/nfs/nfs42proc.c +++ b/fs/nfs/nfs42proc.c @@ -21,6 +21,7 @@ #define NFSDBG_FACILITY NFSDBG_PROC static int nfs42_do_offload_cancel_async(struct file *dst, nfs4_stateid *std); +static int nfs42_proc_offload_status(struct file *file, nfs4_stateid *stateid); static void nfs42_set_netaddr(struct file *filep, struct nfs42_netaddr *naddr) { @@ -173,6 +174,9 @@ int nfs42_proc_deallocate(struct file *filep, loff_t offset, loff_t len) return err; } +/* Wait this long before checking progress on a COPY operation */ +#define NFS42_COPY_TIMEOUT (7 * HZ) + static int handle_async_copy(struct nfs42_copy_res *res, struct nfs_server *dst_server, struct nfs_server *src_server, @@ -222,7 +226,9 @@ static int handle_async_copy(struct nfs42_copy_res *res, spin_unlock(&src_server->nfs_client->cl_lock); } - status = wait_for_completion_interruptible(©->completion); +wait: + status = wait_for_completion_interruptible_timeout(©->completion, + NFS42_COPY_TIMEOUT); spin_lock(&dst_server->nfs_client->cl_lock); list_del_init(©->copies); spin_unlock(&dst_server->nfs_client->cl_lock); @@ -231,12 +237,20 @@ static int handle_async_copy(struct nfs42_copy_res *res, list_del_init(©->src_copies); spin_unlock(&src_server->nfs_client->cl_lock); } - if (status == -ERESTARTSYS) { - goto out_cancel; - } else if (copy->flags || copy->error == NFS4ERR_PARTNER_NO_AUTH) { - status = -EAGAIN; - *restart = true; + switch (status) { + case 0: + status = nfs42_proc_offload_status(src, src_stateid); + if (status && status != -EOPNOTSUPP) + goto wait; + break; + case -ERESTARTSYS: goto out_cancel; + default: + if (copy->flags || copy->error == NFS4ERR_PARTNER_NO_AUTH) { + status = -EAGAIN; + *restart = true; + goto out_cancel; + } } out: res->write_res.count = copy->count; @@ -582,6 +596,80 @@ static int nfs42_do_offload_cancel_async(struct file *dst, return status; } +static void nfs42_offload_status_prepare(struct rpc_task *task, void *calldata) +{ + struct nfs42_offload_data *data = calldata; + + nfs4_setup_sequence(data->seq_server->nfs_client, + &data->args.osa_seq_args, + &data->res.osr_seq_res, task); +} + +static void nfs42_offload_status_done(struct rpc_task *task, void *calldata) +{ + struct nfs42_offload_data *data = calldata; + + trace_nfs4_offload_status(&data->args, task->tk_status); + nfs41_sequence_done(task, &data->res.osr_seq_res); + if (task->tk_status && + nfs4_async_handle_error(task, data->seq_server, NULL, + NULL) == -EAGAIN) + rpc_restart_call_prepare(task); +} + +static const struct rpc_call_ops nfs42_offload_status_ops = { + .rpc_call_prepare = nfs42_offload_status_prepare, + .rpc_call_done = nfs42_offload_status_done, + .rpc_release = nfs42_free_offload_data, +}; + +static int nfs42_proc_offload_status(struct file *file, nfs4_stateid *stateid) +{ + struct nfs_open_context *ctx = nfs_file_open_context(file); + struct nfs_server *server = NFS_SERVER(file_inode(file)); + struct nfs42_offload_data *data = NULL; + struct rpc_task *task; + struct rpc_message msg = { + .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OFFLOAD_STATUS], + .rpc_cred = ctx->cred, + }; + struct rpc_task_setup task_setup_data = { + .rpc_client = server->client, + .rpc_message = &msg, + .callback_ops = &nfs42_offload_status_ops, + .workqueue = nfsiod_workqueue, + .flags = RPC_TASK_ASYNC | RPC_TASK_SOFTCONN, + }; + int status; + + if (!(server->caps & NFS_CAP_OFFLOAD_STATUS)) + return -EOPNOTSUPP; + + data = kzalloc(sizeof(struct nfs42_offload_data), GFP_KERNEL); + if (data == NULL) + return -ENOMEM; + + data->seq_server = server; + data->args.osa_src_fh = NFS_FH(file_inode(file)); + memcpy(&data->args.osa_stateid, stateid, + sizeof(data->args.osa_stateid)); + msg.rpc_argp = &data->args; + msg.rpc_resp = &data->res; + task_setup_data.callback_data = data; + nfs4_init_sequence(&data->args.osa_seq_args, &data->res.osr_seq_res, + 1, 0); + task = rpc_run_task(&task_setup_data); + if (IS_ERR(task)) { + nfs42_free_offload_data(data); + return PTR_ERR(task); + } + status = rpc_wait_for_completion_task(task); + if (status == -ENOTSUPP) + server->caps &= ~NFS_CAP_OFFLOAD_STATUS; + rpc_put_task(task); + return status; +} + static int _nfs42_proc_copy_notify(struct file *src, struct file *dst, struct nfs42_copy_notify_args *args, struct nfs42_copy_notify_res *res) diff --git a/fs/nfs/nfs4trace.h b/fs/nfs/nfs4trace.h index 8f32dbf9c91d..9bcc525c71d1 100644 --- a/fs/nfs/nfs4trace.h +++ b/fs/nfs/nfs4trace.h @@ -2564,6 +2564,7 @@ DECLARE_EVENT_CLASS(nfs4_offload_class, ), \ TP_ARGS(args, error)) DEFINE_NFS4_OFFLOAD_EVENT(nfs4_offload_cancel); +DEFINE_NFS4_OFFLOAD_EVENT(nfs4_offload_status); DECLARE_EVENT_CLASS(nfs4_xattr_event, TP_PROTO( diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h index 92de074e63b9..0937e73c4767 100644 --- a/include/linux/nfs_fs_sb.h +++ b/include/linux/nfs_fs_sb.h @@ -278,6 +278,7 @@ struct nfs_server { #define NFS_CAP_LGOPEN (1U << 5) #define NFS_CAP_CASE_INSENSITIVE (1U << 6) #define NFS_CAP_CASE_PRESERVING (1U << 7) +#define NFS_CAP_OFFLOAD_STATUS (1U << 8) #define NFS_CAP_POSIX_LOCK (1U << 14) #define NFS_CAP_UIDGID_NOMAP (1U << 15) #define NFS_CAP_STATEID_NFSV41 (1U << 16) -- 2.44.0
