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1 | /* |
2 | * Copyright (c) 2011-2012 The DragonFly Project. All rights reserved. | |
3 | * | |
4 | * This code is derived from software contributed to The DragonFly Project | |
5 | * by Matthew Dillon <dillon@dragonflybsd.org> | |
6 | * by Venkatesh Srinivas <vsrinivas@dragonflybsd.org> | |
7 | * | |
8 | * Redistribution and use in source and binary forms, with or without | |
9 | * modification, are permitted provided that the following conditions | |
10 | * are met: | |
11 | * | |
12 | * 1. Redistributions of source code must retain the above copyright | |
13 | * notice, this list of conditions and the following disclaimer. | |
14 | * 2. Redistributions in binary form must reproduce the above copyright | |
15 | * notice, this list of conditions and the following disclaimer in | |
16 | * the documentation and/or other materials provided with the | |
17 | * distribution. | |
18 | * 3. Neither the name of The DragonFly Project nor the names of its | |
19 | * contributors may be used to endorse or promote products derived | |
20 | * from this software without specific, prior written permission. | |
21 | * | |
22 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
23 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
24 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS | |
25 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE | |
26 | * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, | |
27 | * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, | |
28 | * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
29 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED | |
30 | * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, | |
31 | * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT | |
32 | * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
33 | * SUCH DAMAGE. | |
34 | */ | |
35 | ||
36 | #include "hammer2.h" | |
37 | ||
38 | /* | |
39 | * Start-up the leaf daemon for a PFS on this machine. | |
40 | * | |
41 | * One leaf daemon is run for each mounted PFS. The daemon may multi-thread | |
42 | * to improve performance if desired. The daemon performs the following | |
43 | * functions: | |
44 | * | |
45 | * (1) Makes and maintains connections to all cluster nodes found for | |
46 | * the PFS, retrieved from the REMOTE configuration stored in | |
47 | * the HAMMER2 mount. A localhost connection is always implied | |
48 | * (using the backbone), but also having more direct connections | |
49 | * can result in higher performance. | |
50 | * | |
51 | * This also includes any required encryption or authentication. | |
52 | * | |
53 | * (2) Runs the spanning tree protocol as a leaf, meaning that | |
54 | * the leaf daemon does not serve as a relay and the individual | |
55 | * connections made in (1) do not cross-connect. | |
56 | * | |
57 | * (3) Obtains the PFS's registration and makes it available to the | |
58 | * cluster via the spanning tree protocol. | |
59 | * | |
60 | * (4) Creates a communications pipe to the HAMMER2 VFS in the kernel | |
61 | * (installed via ioctl()) which the HAMMER2 VFS uses to accept and | |
62 | * communicate high-level requests. | |
63 | * | |
64 | * (5) Performs all complex high-level messaging protocol operations, | |
65 | * such as quorum operations, maintains persistent cache state, | |
66 | * and so on and so forth. | |
67 | * | |
68 | * As you may have noted, the leaf daemon serves as an intermediary between | |
69 | * the kernel and the rest of the cluster. The kernel will issue high level | |
70 | * protocol commands to the leaf which performs the protocol and sends a | |
71 | * response. The kernel does NOT have to deal with the quorum or other | |
72 | * complex maintainance. | |
73 | * | |
74 | * Basically the kernel is simply another client from the point of view | |
75 | * of the high-level protocols, requesting cache state locks and such from | |
76 | * the leaf (in a degenerate situation one master lock is all that is needed). | |
77 | * If the kernel PFS has local media storage that storage can be used for | |
78 | * numerous purposes, such as caching, and in the degenerate non-clustered | |
79 | * case simply represents the one-and-only master copy of the filesystem. | |
80 | */ | |
81 | int | |
82 | cmd_leaf(const char *sel_info) | |
83 | { | |
84 | int ecode = 0; | |
85 | int fd; | |
86 | ||
87 | /* | |
88 | * Obtain an ioctl descriptor and retrieve the registration info | |
89 | * for the PFS. | |
90 | */ | |
91 | if ((fd = hammer2_ioctl_handle(sel_info)) < 0) | |
92 | return(1); | |
93 | ||
94 | /* | |
95 | * Start a daemon to interconnect the HAMMER2 PFS in-kernel to the | |
96 | * master-node daemon. This daemon's thread will spend most of its | |
97 | * time in the kernel. | |
98 | */ | |
99 | /* hammer2_demon(helper_pfs_interlink, (void *)(intptr_t)fd);*/ | |
100 | if (NormalExit) | |
101 | close(fd); | |
102 | ||
103 | return ecode; | |
104 | } | |
105 | ||
106 | #if 0 | |
107 | /* | |
108 | * LEAF interconnect between PFS and the messaging core. We create a | |
109 | * socket connection to the messaging core, register the PFS with the | |
110 | * core, and then pass the messaging descriptor to the kernel. | |
111 | * | |
112 | * The kernel takes over operation of the interconnect until the filesystem | |
113 | * is unmounted or the descriptor is lost or explicitly terminated via | |
114 | * a hammer2 command. | |
115 | * | |
116 | * This is essentially a localhost connection, so we don't have to worry | |
117 | * about encryption. Any encryption will be handled by the messaging | |
118 | * core. | |
119 | */ | |
120 | static | |
121 | void * | |
122 | leaf_connect(void *data) | |
123 | { | |
124 | int fd; | |
125 | ||
126 | fd = (int)(intptr_t)data; | |
127 | ||
128 | return (NULL); | |
129 | } | |
130 | #endif |