Commit | Line | Data |
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ec26815a | 1 | /* AFS server record management |
1da177e4 | 2 | * |
08e0e7c8 | 3 | * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved. |
1da177e4 LT |
4 | * Written by David Howells (dhowells@redhat.com) |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/sched.h> | |
13 | #include <linux/slab.h> | |
1da177e4 LT |
14 | #include "internal.h" |
15 | ||
c1206a2c | 16 | static unsigned afs_server_timeout = 10; /* server timeout in seconds */ |
1da177e4 | 17 | |
08e0e7c8 | 18 | static void afs_reap_server(struct work_struct *); |
1da177e4 | 19 | |
08e0e7c8 DH |
20 | /* tree of all the servers, indexed by IP address */ |
21 | static struct rb_root afs_servers = RB_ROOT; | |
22 | static DEFINE_RWLOCK(afs_servers_lock); | |
23 | ||
24 | /* LRU list of all the servers not currently in use */ | |
25 | static LIST_HEAD(afs_server_graveyard); | |
26 | static DEFINE_SPINLOCK(afs_server_graveyard_lock); | |
27 | static DECLARE_DELAYED_WORK(afs_server_reaper, afs_reap_server); | |
28 | ||
29 | /* | |
30 | * install a server record in the master tree | |
31 | */ | |
32 | static int afs_install_server(struct afs_server *server) | |
1da177e4 | 33 | { |
08e0e7c8 DH |
34 | struct afs_server *xserver; |
35 | struct rb_node **pp, *p; | |
36 | int ret; | |
37 | ||
38 | _enter("%p", server); | |
1da177e4 | 39 | |
08e0e7c8 DH |
40 | write_lock(&afs_servers_lock); |
41 | ||
42 | ret = -EEXIST; | |
43 | pp = &afs_servers.rb_node; | |
44 | p = NULL; | |
45 | while (*pp) { | |
46 | p = *pp; | |
47 | _debug("- consider %p", p); | |
48 | xserver = rb_entry(p, struct afs_server, master_rb); | |
49 | if (server->addr.s_addr < xserver->addr.s_addr) | |
50 | pp = &(*pp)->rb_left; | |
51 | else if (server->addr.s_addr > xserver->addr.s_addr) | |
52 | pp = &(*pp)->rb_right; | |
53 | else | |
54 | goto error; | |
55 | } | |
1da177e4 | 56 | |
08e0e7c8 DH |
57 | rb_link_node(&server->master_rb, p, pp); |
58 | rb_insert_color(&server->master_rb, &afs_servers); | |
59 | ret = 0; | |
1da177e4 | 60 | |
08e0e7c8 DH |
61 | error: |
62 | write_unlock(&afs_servers_lock); | |
63 | return ret; | |
64 | } | |
1da177e4 | 65 | |
1da177e4 | 66 | /* |
08e0e7c8 | 67 | * allocate a new server record |
1da177e4 | 68 | */ |
08e0e7c8 DH |
69 | static struct afs_server *afs_alloc_server(struct afs_cell *cell, |
70 | const struct in_addr *addr) | |
1da177e4 | 71 | { |
08e0e7c8 | 72 | struct afs_server *server; |
1da177e4 | 73 | |
08e0e7c8 | 74 | _enter(""); |
1da177e4 | 75 | |
b593e48d | 76 | server = kzalloc(sizeof(struct afs_server), GFP_KERNEL); |
08e0e7c8 DH |
77 | if (server) { |
78 | atomic_set(&server->usage, 1); | |
79 | server->cell = cell; | |
80 | ||
81 | INIT_LIST_HEAD(&server->link); | |
82 | INIT_LIST_HEAD(&server->grave); | |
83 | init_rwsem(&server->sem); | |
84 | spin_lock_init(&server->fs_lock); | |
85 | server->fs_vnodes = RB_ROOT; | |
86 | server->cb_promises = RB_ROOT; | |
87 | spin_lock_init(&server->cb_lock); | |
88 | init_waitqueue_head(&server->cb_break_waitq); | |
89 | INIT_DELAYED_WORK(&server->cb_break_work, | |
90 | afs_dispatch_give_up_callbacks); | |
91 | ||
92 | memcpy(&server->addr, addr, sizeof(struct in_addr)); | |
93 | server->addr.s_addr = addr->s_addr; | |
037776fc DK |
94 | _leave(" = %p{%d}", server, atomic_read(&server->usage)); |
95 | } else { | |
96 | _leave(" = NULL [nomem]"); | |
1da177e4 | 97 | } |
08e0e7c8 DH |
98 | return server; |
99 | } | |
1da177e4 | 100 | |
08e0e7c8 DH |
101 | /* |
102 | * get an FS-server record for a cell | |
103 | */ | |
104 | struct afs_server *afs_lookup_server(struct afs_cell *cell, | |
105 | const struct in_addr *addr) | |
106 | { | |
107 | struct afs_server *server, *candidate; | |
1da177e4 | 108 | |
be859405 | 109 | _enter("%p,%pI4", cell, &addr->s_addr); |
1da177e4 | 110 | |
08e0e7c8 DH |
111 | /* quick scan of the list to see if we already have the server */ |
112 | read_lock(&cell->servers_lock); | |
1da177e4 | 113 | |
08e0e7c8 DH |
114 | list_for_each_entry(server, &cell->servers, link) { |
115 | if (server->addr.s_addr == addr->s_addr) | |
116 | goto found_server_quickly; | |
1da177e4 | 117 | } |
08e0e7c8 | 118 | read_unlock(&cell->servers_lock); |
1da177e4 | 119 | |
08e0e7c8 DH |
120 | candidate = afs_alloc_server(cell, addr); |
121 | if (!candidate) { | |
122 | _leave(" = -ENOMEM"); | |
123 | return ERR_PTR(-ENOMEM); | |
1da177e4 | 124 | } |
1da177e4 | 125 | |
08e0e7c8 | 126 | write_lock(&cell->servers_lock); |
1da177e4 | 127 | |
08e0e7c8 DH |
128 | /* check the cell's server list again */ |
129 | list_for_each_entry(server, &cell->servers, link) { | |
130 | if (server->addr.s_addr == addr->s_addr) | |
131 | goto found_server; | |
132 | } | |
133 | ||
134 | _debug("new"); | |
135 | server = candidate; | |
136 | if (afs_install_server(server) < 0) | |
137 | goto server_in_two_cells; | |
1da177e4 | 138 | |
08e0e7c8 DH |
139 | afs_get_cell(cell); |
140 | list_add_tail(&server->link, &cell->servers); | |
141 | ||
142 | write_unlock(&cell->servers_lock); | |
143 | _leave(" = %p{%d}", server, atomic_read(&server->usage)); | |
144 | return server; | |
145 | ||
146 | /* found a matching server quickly */ | |
147 | found_server_quickly: | |
148 | _debug("found quickly"); | |
149 | afs_get_server(server); | |
150 | read_unlock(&cell->servers_lock); | |
151 | no_longer_unused: | |
152 | if (!list_empty(&server->grave)) { | |
153 | spin_lock(&afs_server_graveyard_lock); | |
154 | list_del_init(&server->grave); | |
155 | spin_unlock(&afs_server_graveyard_lock); | |
156 | } | |
157 | _leave(" = %p{%d}", server, atomic_read(&server->usage)); | |
158 | return server; | |
159 | ||
160 | /* found a matching server on the second pass */ | |
161 | found_server: | |
162 | _debug("found"); | |
163 | afs_get_server(server); | |
164 | write_unlock(&cell->servers_lock); | |
165 | kfree(candidate); | |
166 | goto no_longer_unused; | |
167 | ||
168 | /* found a server that seems to be in two cells */ | |
169 | server_in_two_cells: | |
170 | write_unlock(&cell->servers_lock); | |
171 | kfree(candidate); | |
be859405 HH |
172 | printk(KERN_NOTICE "kAFS: Server %pI4 appears to be in two cells\n", |
173 | addr); | |
08e0e7c8 DH |
174 | _leave(" = -EEXIST"); |
175 | return ERR_PTR(-EEXIST); | |
176 | } | |
1da177e4 | 177 | |
08e0e7c8 DH |
178 | /* |
179 | * look up a server by its IP address | |
180 | */ | |
8324f0bc | 181 | struct afs_server *afs_find_server(const struct sockaddr_rxrpc *srx) |
08e0e7c8 DH |
182 | { |
183 | struct afs_server *server = NULL; | |
184 | struct rb_node *p; | |
8324f0bc | 185 | struct in_addr addr = srx->transport.sin.sin_addr; |
1da177e4 | 186 | |
8324f0bc DH |
187 | _enter("{%d,%pI4}", srx->transport.family, &addr.s_addr); |
188 | ||
189 | if (srx->transport.family != AF_INET) { | |
190 | WARN(true, "AFS does not yes support non-IPv4 addresses\n"); | |
191 | return NULL; | |
192 | } | |
1da177e4 | 193 | |
08e0e7c8 | 194 | read_lock(&afs_servers_lock); |
1da177e4 | 195 | |
08e0e7c8 DH |
196 | p = afs_servers.rb_node; |
197 | while (p) { | |
198 | server = rb_entry(p, struct afs_server, master_rb); | |
1da177e4 | 199 | |
08e0e7c8 | 200 | _debug("- consider %p", p); |
1da177e4 | 201 | |
08e0e7c8 DH |
202 | if (addr.s_addr < server->addr.s_addr) { |
203 | p = p->rb_left; | |
204 | } else if (addr.s_addr > server->addr.s_addr) { | |
205 | p = p->rb_right; | |
206 | } else { | |
207 | afs_get_server(server); | |
208 | goto found; | |
209 | } | |
210 | } | |
1da177e4 | 211 | |
08e0e7c8 DH |
212 | server = NULL; |
213 | found: | |
214 | read_unlock(&afs_servers_lock); | |
215 | ASSERTIFCMP(server, server->addr.s_addr, ==, addr.s_addr); | |
216 | _leave(" = %p", server); | |
217 | return server; | |
ec26815a | 218 | } |
1da177e4 | 219 | |
1da177e4 LT |
220 | /* |
221 | * destroy a server record | |
222 | * - removes from the cell list | |
223 | */ | |
224 | void afs_put_server(struct afs_server *server) | |
225 | { | |
1da177e4 LT |
226 | if (!server) |
227 | return; | |
228 | ||
08e0e7c8 | 229 | _enter("%p{%d}", server, atomic_read(&server->usage)); |
1da177e4 | 230 | |
260a9803 DH |
231 | _debug("PUT SERVER %d", atomic_read(&server->usage)); |
232 | ||
08e0e7c8 | 233 | ASSERTCMP(atomic_read(&server->usage), >, 0); |
1da177e4 LT |
234 | |
235 | if (likely(!atomic_dec_and_test(&server->usage))) { | |
1da177e4 LT |
236 | _leave(""); |
237 | return; | |
238 | } | |
239 | ||
08e0e7c8 | 240 | afs_flush_callback_breaks(server); |
1da177e4 | 241 | |
08e0e7c8 DH |
242 | spin_lock(&afs_server_graveyard_lock); |
243 | if (atomic_read(&server->usage) == 0) { | |
244 | list_move_tail(&server->grave, &afs_server_graveyard); | |
8a79790b | 245 | server->time_of_death = ktime_get_real_seconds(); |
0ad53eee TH |
246 | queue_delayed_work(afs_wq, &afs_server_reaper, |
247 | afs_server_timeout * HZ); | |
08e0e7c8 DH |
248 | } |
249 | spin_unlock(&afs_server_graveyard_lock); | |
250 | _leave(" [dead]"); | |
ec26815a | 251 | } |
1da177e4 | 252 | |
1da177e4 | 253 | /* |
08e0e7c8 | 254 | * destroy a dead server |
1da177e4 | 255 | */ |
08e0e7c8 | 256 | static void afs_destroy_server(struct afs_server *server) |
1da177e4 | 257 | { |
1da177e4 LT |
258 | _enter("%p", server); |
259 | ||
416351f2 DH |
260 | ASSERTIF(server->cb_break_head != server->cb_break_tail, |
261 | delayed_work_pending(&server->cb_break_work)); | |
262 | ||
08e0e7c8 DH |
263 | ASSERTCMP(server->fs_vnodes.rb_node, ==, NULL); |
264 | ASSERTCMP(server->cb_promises.rb_node, ==, NULL); | |
265 | ASSERTCMP(server->cb_break_head, ==, server->cb_break_tail); | |
266 | ASSERTCMP(atomic_read(&server->cb_break_n), ==, 0); | |
1da177e4 | 267 | |
08e0e7c8 | 268 | afs_put_cell(server->cell); |
1da177e4 | 269 | kfree(server); |
ec26815a | 270 | } |
1da177e4 | 271 | |
1da177e4 | 272 | /* |
08e0e7c8 | 273 | * reap dead server records |
1da177e4 | 274 | */ |
08e0e7c8 | 275 | static void afs_reap_server(struct work_struct *work) |
1da177e4 | 276 | { |
08e0e7c8 DH |
277 | LIST_HEAD(corpses); |
278 | struct afs_server *server; | |
279 | unsigned long delay, expiry; | |
8a79790b | 280 | time64_t now; |
08e0e7c8 | 281 | |
8a79790b | 282 | now = ktime_get_real_seconds(); |
08e0e7c8 DH |
283 | spin_lock(&afs_server_graveyard_lock); |
284 | ||
285 | while (!list_empty(&afs_server_graveyard)) { | |
286 | server = list_entry(afs_server_graveyard.next, | |
287 | struct afs_server, grave); | |
288 | ||
289 | /* the queue is ordered most dead first */ | |
290 | expiry = server->time_of_death + afs_server_timeout; | |
291 | if (expiry > now) { | |
292 | delay = (expiry - now) * HZ; | |
41f63c53 | 293 | mod_delayed_work(afs_wq, &afs_server_reaper, delay); |
08e0e7c8 | 294 | break; |
1da177e4 LT |
295 | } |
296 | ||
08e0e7c8 DH |
297 | write_lock(&server->cell->servers_lock); |
298 | write_lock(&afs_servers_lock); | |
299 | if (atomic_read(&server->usage) > 0) { | |
300 | list_del_init(&server->grave); | |
301 | } else { | |
302 | list_move_tail(&server->grave, &corpses); | |
303 | list_del_init(&server->link); | |
304 | rb_erase(&server->master_rb, &afs_servers); | |
1da177e4 | 305 | } |
08e0e7c8 DH |
306 | write_unlock(&afs_servers_lock); |
307 | write_unlock(&server->cell->servers_lock); | |
1da177e4 LT |
308 | } |
309 | ||
08e0e7c8 | 310 | spin_unlock(&afs_server_graveyard_lock); |
1da177e4 | 311 | |
08e0e7c8 DH |
312 | /* now reap the corpses we've extracted */ |
313 | while (!list_empty(&corpses)) { | |
314 | server = list_entry(corpses.next, struct afs_server, grave); | |
315 | list_del(&server->grave); | |
316 | afs_destroy_server(server); | |
1da177e4 | 317 | } |
ec26815a | 318 | } |
1da177e4 | 319 | |
1da177e4 | 320 | /* |
08e0e7c8 | 321 | * discard all the server records for rmmod |
1da177e4 | 322 | */ |
08e0e7c8 | 323 | void __exit afs_purge_servers(void) |
1da177e4 | 324 | { |
08e0e7c8 | 325 | afs_server_timeout = 0; |
41f63c53 | 326 | mod_delayed_work(afs_wq, &afs_server_reaper, 0); |
ec26815a | 327 | } |