smb3: add missing worker function for SMB3 change notify

SMB3 change notify is important to allow applications to wait
on directory change events of different types (e.g. adding
and deleting files from others systems). Add worker functions
for this.

Acked-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index ce647cfdc04fdfefdc2394d3575807e4c5f5af15..87066f1af12c0ccbc8451205efca24df34037940 100644 (file)
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -3175,6 +3175,91 @@ SMB2_get_srv_num(const unsigned int xid, struct cifs_tcon *tcon,
                          (void **)&uniqueid, NULL);
 }
 
+/*
+ * CHANGE_NOTIFY Request is sent to get notifications on changes to a directory
+ * See MS-SMB2 2.2.35 and 2.2.36
+ */
+
+int
+SMB2_notify_init(const unsigned int xid, struct smb_rqst *rqst,
+               struct cifs_tcon *tcon, u64 persistent_fid, u64 volatile_fid,
+               u32 completion_filter, bool watch_tree)
+{
+       struct smb2_change_notify_req *req;
+       struct kvec *iov = rqst->rq_iov;
+       unsigned int total_len;
+       int rc;
+
+       rc = smb2_plain_req_init(SMB2_CHANGE_NOTIFY, tcon, (void **) &req, &total_len);
+       if (rc)
+               return rc;
+
+       req->PersistentFileId = persistent_fid;
+       req->VolatileFileId = volatile_fid;
+       req->OutputBufferLength = SMB2_MAX_BUFFER_SIZE - MAX_SMB2_HDR_SIZE;
+       req->CompletionFilter = cpu_to_le32(completion_filter);
+       if (watch_tree)
+               req->Flags = cpu_to_le16(SMB2_WATCH_TREE);
+       else
+               req->Flags = 0;
+
+       iov[0].iov_base = (char *)req;
+       iov[0].iov_len = total_len;
+
+       return 0;
+}
+
+int
+SMB2_change_notify(const unsigned int xid, struct cifs_tcon *tcon,
+               u64 persistent_fid, u64 volatile_fid, bool watch_tree,
+               u32 completion_filter)
+{
+       struct cifs_ses *ses = tcon->ses;
+       struct smb_rqst rqst;
+       struct kvec iov[1];
+       struct kvec rsp_iov = {NULL, 0};
+       int resp_buftype = CIFS_NO_BUFFER;
+       int flags = 0;
+       int rc = 0;
+
+       cifs_dbg(FYI, "change notify\n");
+       if (!ses || !(ses->server))
+               return -EIO;
+
+       if (smb3_encryption_required(tcon))
+               flags |= CIFS_TRANSFORM_REQ;
+
+       memset(&rqst, 0, sizeof(struct smb_rqst));
+       memset(&iov, 0, sizeof(iov));
+       rqst.rq_iov = iov;
+       rqst.rq_nvec = 1;
+
+       rc = SMB2_notify_init(xid, &rqst, tcon, persistent_fid, volatile_fid,
+                             completion_filter, watch_tree);
+       if (rc)
+               goto cnotify_exit;
+
+       trace_smb3_notify_enter(xid, persistent_fid, tcon->tid, ses->Suid,
+                               (u8)watch_tree, completion_filter);
+       rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
+
+       if (rc != 0) {
+               cifs_stats_fail_inc(tcon, SMB2_CHANGE_NOTIFY_HE);
+               trace_smb3_notify_err(xid, persistent_fid, tcon->tid, ses->Suid,
+                               (u8)watch_tree, completion_filter, rc);
+       } else
+               trace_smb3_notify_done(xid, persistent_fid, tcon->tid,
+                               ses->Suid, (u8)watch_tree, completion_filter);
+
+ cnotify_exit:
+       if (rqst.rq_iov)
+               cifs_small_buf_release(rqst.rq_iov[0].iov_base); /* request */
+       free_rsp_buf(resp_buftype, rsp_iov.iov_base);
+       return rc;
+}
+
+
+
 /*
  * This is a no-op for now. We're not really interested in the reply, but
  * rather in the fact that the server sent one and that server->lstrp

diff --git a/fs/cifs/trace.h b/fs/cifs/trace.h
index f1339f4a2d07e528877ba87fe23ea9d2a6668474..e7e350b13d6a074f6f07cff24979f0675d0100d9 100644 (file)
--- a/fs/cifs/trace.h
+++ b/fs/cifs/trace.h
@@ -235,6 +235,8 @@ DEFINE_EVENT(smb3_inf_enter_class, smb3_##name,    \
 
 DEFINE_SMB3_INF_ENTER_EVENT(query_info_enter);
 DEFINE_SMB3_INF_ENTER_EVENT(query_info_done);
+DEFINE_SMB3_INF_ENTER_EVENT(notify_enter);
+DEFINE_SMB3_INF_ENTER_EVENT(notify_done);
 
 DECLARE_EVENT_CLASS(smb3_inf_err_class,
        TP_PROTO(unsigned int xid,
@@ -281,6 +283,7 @@ DEFINE_EVENT(smb3_inf_err_class, smb3_##name,    \
 
 DEFINE_SMB3_INF_ERR_EVENT(query_info_err);
 DEFINE_SMB3_INF_ERR_EVENT(set_info_err);
+DEFINE_SMB3_INF_ERR_EVENT(notify_err);
 DEFINE_SMB3_INF_ERR_EVENT(fsctl_err);
 
 DECLARE_EVENT_CLASS(smb3_inf_compound_enter_class,