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Diffstat (limited to 'source3/smbd/notifyd/notifyd.h')
| -rw-r--r-- | source3/smbd/notifyd/notifyd.h | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/source3/smbd/notifyd/notifyd.h b/source3/smbd/notifyd/notifyd.h new file mode 100644 index 0000000..5ef8c4c --- /dev/null +++ b/source3/smbd/notifyd/notifyd.h @@ -0,0 +1,145 @@ +/* + * Unix SMB/CIFS implementation. + * + * Copyright (C) Volker Lendecke 2014 + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef __NOTIFYD_NOTIFYD_H__ +#define __NOTIFYD_NOTIFYD_H__ + +#include "includes.h" +#include "librpc/gen_ndr/notify.h" +#include "librpc/gen_ndr/messaging.h" +#include "lib/dbwrap/dbwrap.h" +#include "lib/dbwrap/dbwrap_rbt.h" +#include "messages.h" +#include "tdb.h" +#include "util_tdb.h" + +/* + * Filechangenotify based on asynchronous messages + * + * smbds talk to local notify daemons to inform them about paths they are + * interested in. They also tell local notify daemons about changes they have + * done to the file system. There's two message types from smbd to + * notifyd. The first is used to inform notifyd about changes in notify + * interest. These are only sent from smbd to notifyd if the SMB client issues + * FileChangeNotify requests. + */ + +/* + * The notifyd implementation is designed to cope with multiple daemons taking + * care of just a subset of smbds. The goal is to minimize the traffic between + * the notify daemons. The idea behind this is a samba/ctdb cluster, but it + * could also be used to spread the load of notifyd instances on a single + * node, should this become a bottleneck. The following diagram illustrates + * the setup. The numbers in the boxes are node:process ids. + * + * +-----------+ +-----------+ + * |notifyd 0:5|------------------|notifyd 1:6| + * +-----------+ +-----------+ + * / | \ / \ + * / | \ / \ + * +--------+ | +--------+ +--------+ +--------+ + * |smbd 0:1| | |smbd 0:4| |smbd 1:7| |smbd 1:2| + * +--------+ | +--------+ +--------+ +--------+ + * | + * +---------+ + * |smbd 0:20| + * +---------+ + * + * Suppose 0:1 and 0:4 are interested in changes for /foo and 0:20 creates the + * file /foo/bar, if everything fully connected, 0:20 would have to send two + * local messages, one to 0:1 and one to 0:4. With the notifyd design, 0:20 + * only has to send one message, it lets notifyd 0:5 do the hard work to + * multicast the change to 0:1 and 0:4. + * + * Now lets assume 1:7 on the other node creates /foo/baz. It tells its + * notifyd 1:6 about this change. All 1:6 will know about is that its peer + * notifyd 0:5 is interested in the change. Thus it forwards the event to 0:5, + * which sees it as if it came from just another local event creator. 0:5 will + * multicast the change to 0:1 and 0:4. To prevent notify loops, the message + * from 1:6 to 0:5 will carry a "proxied" flag, so that 0:5 will only forward + * the event to local clients. + */ + +/* + * Data that notifyd maintains per smbd notify instance + */ +struct notify_instance { + struct timespec creation_time; + uint32_t filter; + uint32_t subdir_filter; + void *private_data; +}; + +/* MSG_SMB_NOTIFY_REC_CHANGE payload */ +struct notify_rec_change_msg { + struct notify_instance instance; + char path[]; +}; + +/* + * The second message from smbd to notifyd is sent whenever an smbd makes a + * file system change. It tells notifyd to inform all interested parties about + * that change. This is the message that needs to be really fast in smbd + * because it is called a lot. + */ + +/* MSG_SMB_NOTIFY_TRIGGER payload */ +struct notify_trigger_msg { + struct timespec when; + uint32_t action; + uint32_t filter; + char path[]; +}; + +/* + * In response to a MSG_SMB_NOTIFY_TRIGGER message notifyd walks its database + * and sends out the following message to all interested clients + */ + +/* MSG_PVFS_NOTIFY payload */ +struct notify_event_msg { + struct timespec when; + void *private_data; + uint32_t action; + char path[]; +}; + +struct sys_notify_context; +struct ctdbd_connection; + +typedef int (*sys_notify_watch_fn)(TALLOC_CTX *mem_ctx, + struct sys_notify_context *ctx, + const char *path, + uint32_t *filter, + uint32_t *subdir_filter, + void (*callback)(struct sys_notify_context *ctx, + void *private_data, + struct notify_event *ev, + uint32_t filter), + void *private_data, + void *handle_p); + +struct tevent_req *notifyd_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev, + struct messaging_context *msg_ctx, + struct ctdbd_connection *ctdbd_conn, + sys_notify_watch_fn sys_notify_watch, + struct sys_notify_context *sys_notify_ctx); +int notifyd_recv(struct tevent_req *req); + +#endif |