xref: /linux/fs/afs/callback.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
1 /*
2  * Copyright (c) 2002 Red Hat, Inc. All rights reserved.
3  *
4  * This software may be freely redistributed under the terms of the
5  * GNU General Public License.
6  *
7  * You should have received a copy of the GNU General Public License
8  * along with this program; if not, write to the Free Software
9  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
10  *
11  * Authors: David Woodhouse <dwmw2@cambridge.redhat.com>
12  *          David Howells <dhowells@redhat.com>
13  *
14  */
15 
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include "server.h"
20 #include "vnode.h"
21 #include "internal.h"
22 #include "cmservice.h"
23 
24 /*****************************************************************************/
25 /*
26  * allow the fileserver to request callback state (re-)initialisation
27  */
28 int SRXAFSCM_InitCallBackState(struct afs_server *server)
29 {
30 	struct list_head callbacks;
31 
32 	_enter("%p", server);
33 
34 	INIT_LIST_HEAD(&callbacks);
35 
36 	/* transfer the callback list from the server to a temp holding area */
37 	spin_lock(&server->cb_lock);
38 
39 	list_add(&callbacks, &server->cb_promises);
40 	list_del_init(&server->cb_promises);
41 
42 	/* munch our way through the list, grabbing the inode, dropping all the
43 	 * locks and regetting them in the right order
44 	 */
45 	while (!list_empty(&callbacks)) {
46 		struct afs_vnode *vnode;
47 		struct inode *inode;
48 
49 		vnode = list_entry(callbacks.next, struct afs_vnode, cb_link);
50 		list_del_init(&vnode->cb_link);
51 
52 		/* try and grab the inode - may fail */
53 		inode = igrab(AFS_VNODE_TO_I(vnode));
54 		if (inode) {
55 			int release = 0;
56 
57 			spin_unlock(&server->cb_lock);
58 			spin_lock(&vnode->lock);
59 
60 			if (vnode->cb_server == server) {
61 				vnode->cb_server = NULL;
62 				afs_kafstimod_del_timer(&vnode->cb_timeout);
63 				spin_lock(&afs_cb_hash_lock);
64 				list_del_init(&vnode->cb_hash_link);
65 				spin_unlock(&afs_cb_hash_lock);
66 				release = 1;
67 			}
68 
69 			spin_unlock(&vnode->lock);
70 
71 			iput(inode);
72 			afs_put_server(server);
73 
74 			spin_lock(&server->cb_lock);
75 		}
76 	}
77 
78 	spin_unlock(&server->cb_lock);
79 
80 	_leave(" = 0");
81 	return 0;
82 } /* end SRXAFSCM_InitCallBackState() */
83 
84 /*****************************************************************************/
85 /*
86  * allow the fileserver to break callback promises
87  */
88 int SRXAFSCM_CallBack(struct afs_server *server, size_t count,
89 		      struct afs_callback callbacks[])
90 {
91 	_enter("%p,%u,", server, count);
92 
93 	for (; count > 0; callbacks++, count--) {
94 		struct afs_vnode *vnode = NULL;
95 		struct inode *inode = NULL;
96 		int valid = 0;
97 
98 		_debug("- Fid { vl=%08x n=%u u=%u }  CB { v=%u x=%u t=%u }",
99 		       callbacks->fid.vid,
100 		       callbacks->fid.vnode,
101 		       callbacks->fid.unique,
102 		       callbacks->version,
103 		       callbacks->expiry,
104 		       callbacks->type
105 		       );
106 
107 		/* find the inode for this fid */
108 		spin_lock(&afs_cb_hash_lock);
109 
110 		list_for_each_entry(vnode,
111 				    &afs_cb_hash(server, &callbacks->fid),
112 				    cb_hash_link) {
113 			if (memcmp(&vnode->fid, &callbacks->fid,
114 				   sizeof(struct afs_fid)) != 0)
115 				continue;
116 
117 			/* right vnode, but is it same server? */
118 			if (vnode->cb_server != server)
119 				break; /* no */
120 
121 			/* try and nail the inode down */
122 			inode = igrab(AFS_VNODE_TO_I(vnode));
123 			break;
124 		}
125 
126 		spin_unlock(&afs_cb_hash_lock);
127 
128 		if (inode) {
129 			/* we've found the record for this vnode */
130 			spin_lock(&vnode->lock);
131 			if (vnode->cb_server == server) {
132 				/* the callback _is_ on the calling server */
133 				vnode->cb_server = NULL;
134 				valid = 1;
135 
136 				afs_kafstimod_del_timer(&vnode->cb_timeout);
137 				vnode->flags |= AFS_VNODE_CHANGED;
138 
139 				spin_lock(&server->cb_lock);
140 				list_del_init(&vnode->cb_link);
141 				spin_unlock(&server->cb_lock);
142 
143 				spin_lock(&afs_cb_hash_lock);
144 				list_del_init(&vnode->cb_hash_link);
145 				spin_unlock(&afs_cb_hash_lock);
146 			}
147 			spin_unlock(&vnode->lock);
148 
149 			if (valid) {
150 				invalidate_remote_inode(inode);
151 				afs_put_server(server);
152 			}
153 			iput(inode);
154 		}
155 	}
156 
157 	_leave(" = 0");
158 	return 0;
159 } /* end SRXAFSCM_CallBack() */
160 
161 /*****************************************************************************/
162 /*
163  * allow the fileserver to see if the cache manager is still alive
164  */
165 int SRXAFSCM_Probe(struct afs_server *server)
166 {
167 	_debug("SRXAFSCM_Probe(%p)\n", server);
168 	return 0;
169 } /* end SRXAFSCM_Probe() */
170