1 /* AFS vnode management
3 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/slab.h>
20 static noinline bool dump_tree_aux(struct rb_node *node, struct rb_node *parent,
23 struct afs_vnode *vnode;
30 bad = dump_tree_aux(node->rb_left, node, depth + 2, '/');
32 vnode = rb_entry(node, struct afs_vnode, cb_promise);
33 kdebug("%c %*.*s%c%p {%d}",
34 rb_is_red(node) ? 'R' : 'B',
36 vnode, vnode->cb_expires_at);
37 if (rb_parent(node) != parent) {
38 printk("BAD: %p != %p\n", rb_parent(node), parent);
43 bad |= dump_tree_aux(node->rb_right, node, depth + 2, '\\');
48 static noinline void dump_tree(const char *name, struct afs_server *server)
51 if (dump_tree_aux(server->cb_promises.rb_node, NULL, 0, '-'))
57 * insert a vnode into the backing server's vnode tree
59 static void afs_install_vnode(struct afs_vnode *vnode,
60 struct afs_server *server)
62 struct afs_server *old_server = vnode->server;
63 struct afs_vnode *xvnode;
64 struct rb_node *parent, **p;
66 _enter("%p,%p", vnode, server);
69 spin_lock(&old_server->fs_lock);
70 rb_erase(&vnode->server_rb, &old_server->fs_vnodes);
71 spin_unlock(&old_server->fs_lock);
74 afs_get_server(server);
75 vnode->server = server;
76 afs_put_server(old_server);
78 /* insert into the server's vnode tree in FID order */
79 spin_lock(&server->fs_lock);
82 p = &server->fs_vnodes.rb_node;
85 xvnode = rb_entry(parent, struct afs_vnode, server_rb);
86 if (vnode->fid.vid < xvnode->fid.vid)
88 else if (vnode->fid.vid > xvnode->fid.vid)
90 else if (vnode->fid.vnode < xvnode->fid.vnode)
92 else if (vnode->fid.vnode > xvnode->fid.vnode)
94 else if (vnode->fid.unique < xvnode->fid.unique)
96 else if (vnode->fid.unique > xvnode->fid.unique)
99 BUG(); /* can't happen unless afs_iget() malfunctions */
102 rb_link_node(&vnode->server_rb, parent, p);
103 rb_insert_color(&vnode->server_rb, &server->fs_vnodes);
105 spin_unlock(&server->fs_lock);
110 * insert a vnode into the promising server's update/expiration tree
111 * - caller must hold vnode->lock
113 static void afs_vnode_note_promise(struct afs_vnode *vnode,
114 struct afs_server *server)
116 struct afs_server *old_server;
117 struct afs_vnode *xvnode;
118 struct rb_node *parent, **p;
120 _enter("%p,%p", vnode, server);
122 ASSERT(server != NULL);
124 old_server = vnode->server;
125 if (vnode->cb_promised) {
126 if (server == old_server &&
127 vnode->cb_expires == vnode->cb_expires_at) {
128 _leave(" [no change]");
132 spin_lock(&old_server->cb_lock);
133 if (vnode->cb_promised) {
135 rb_erase(&vnode->cb_promise, &old_server->cb_promises);
136 vnode->cb_promised = false;
138 spin_unlock(&old_server->cb_lock);
141 if (vnode->server != server)
142 afs_install_vnode(vnode, server);
144 vnode->cb_expires_at = vnode->cb_expires;
145 _debug("PROMISE on %p {%lu}",
146 vnode, (unsigned long) vnode->cb_expires_at);
148 /* abuse an RB-tree to hold the expiration order (we may have multiple
149 * items with the same expiration time) */
150 spin_lock(&server->cb_lock);
153 p = &server->cb_promises.rb_node;
156 xvnode = rb_entry(parent, struct afs_vnode, cb_promise);
157 if (vnode->cb_expires_at < xvnode->cb_expires_at)
163 rb_link_node(&vnode->cb_promise, parent, p);
164 rb_insert_color(&vnode->cb_promise, &server->cb_promises);
165 vnode->cb_promised = true;
167 spin_unlock(&server->cb_lock);
172 * handle remote file deletion by discarding the callback promise
174 static void afs_vnode_deleted_remotely(struct afs_vnode *vnode)
176 struct afs_server *server;
178 set_bit(AFS_VNODE_DELETED, &vnode->flags);
180 server = vnode->server;
181 if (vnode->cb_promised) {
182 spin_lock(&server->cb_lock);
183 if (vnode->cb_promised) {
184 rb_erase(&vnode->cb_promise, &server->cb_promises);
185 vnode->cb_promised = false;
187 spin_unlock(&server->cb_lock);
190 afs_put_server(server);
194 * finish off updating the recorded status of a file
195 * - starts callback expiry timer
196 * - adds to server's callback list
198 static void afs_vnode_finalise_status_update(struct afs_vnode *vnode,
199 struct afs_server *server,
202 struct afs_server *oldserver = NULL;
204 _enter("%p,%p,%d", vnode, server, ret);
206 spin_lock(&vnode->lock);
208 clear_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
212 afs_vnode_note_promise(vnode, server);
215 /* the file was deleted on the server */
216 _debug("got NOENT from server - marking file deleted");
217 afs_vnode_deleted_remotely(vnode);
225 spin_unlock(&vnode->lock);
227 wake_up_all(&vnode->update_waitq);
229 afs_put_server(oldserver);
235 * fetch file status from the volume
236 * - don't issue a fetch if:
237 * - the changed bit is not set and there's a valid callback
238 * - there are any outstanding ops that will fetch the status
239 * - TODO implement local caching
241 int afs_vnode_fetch_status(struct afs_vnode *vnode)
243 struct afs_server *server;
246 DECLARE_WAITQUEUE(myself, current);
248 _enter("%s,{%u,%u,%u}",
249 vnode->volume->vlocation->vldb.name,
250 vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);
252 if (!test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
253 vnode->cb_promised) {
254 _leave(" [unchanged]");
258 if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
259 _leave(" [deleted]");
263 spin_lock(&vnode->lock);
265 if (!test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
266 vnode->cb_promised) {
267 spin_unlock(&vnode->lock);
268 _leave(" [unchanged]");
272 if (vnode->update_cnt > 0) {
273 /* someone else started a fetch */
274 set_current_state(TASK_UNINTERRUPTIBLE);
275 ASSERT(myself.func != NULL);
276 add_wait_queue(&vnode->update_waitq, &myself);
278 /* wait for the status to be updated */
280 if (!test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags))
282 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
285 /* check to see if it got updated and invalidated all
286 * before we saw it */
287 if (vnode->update_cnt == 0) {
288 remove_wait_queue(&vnode->update_waitq,
290 set_current_state(TASK_RUNNING);
294 spin_unlock(&vnode->lock);
297 set_current_state(TASK_UNINTERRUPTIBLE);
299 spin_lock(&vnode->lock);
302 remove_wait_queue(&vnode->update_waitq, &myself);
303 spin_unlock(&vnode->lock);
304 set_current_state(TASK_RUNNING);
306 return test_bit(AFS_VNODE_DELETED, &vnode->flags) ?
311 /* okay... we're going to have to initiate the op */
314 spin_unlock(&vnode->lock);
316 /* merge AFS status fetches and clear outstanding callback on this
319 /* pick a server to query */
320 server = afs_volume_pick_fileserver(vnode);
322 return PTR_ERR(server);
324 _debug("USING SERVER: %p{%08x}",
325 server, ntohl(server->addr.s_addr));
327 ret = afs_fs_fetch_file_status(server, vnode, NULL,
330 } while (!afs_volume_release_fileserver(vnode, server, ret));
332 /* adjust the flags */
333 afs_vnode_finalise_status_update(vnode, server, ret);
335 _leave(" = %d", ret);
340 * fetch file data from the volume
341 * - TODO implement caching and server failover
343 int afs_vnode_fetch_data(struct afs_vnode *vnode, off_t offset, size_t length,
346 struct afs_server *server;
349 _enter("%s,{%u,%u,%u}",
350 vnode->volume->vlocation->vldb.name,
355 /* this op will fetch the status */
356 spin_lock(&vnode->lock);
358 spin_unlock(&vnode->lock);
360 /* merge in AFS status fetches and clear outstanding callback on this
363 /* pick a server to query */
364 server = afs_volume_pick_fileserver(vnode);
366 return PTR_ERR(server);
368 _debug("USING SERVER: %08x\n", ntohl(server->addr.s_addr));
370 ret = afs_fs_fetch_data(server, vnode, offset, length, page,
371 NULL, &afs_sync_call);
373 } while (!afs_volume_release_fileserver(vnode, server, ret));
375 /* adjust the flags */
376 afs_vnode_finalise_status_update(vnode, server, ret);
378 _leave(" = %d", ret);