xref: /openbmc/linux/fs/afs/callback.c (revision 1da177e4)
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 
23 /*****************************************************************************/
24 /*
25  * allow the fileserver to request callback state (re-)initialisation
26  */
27 int SRXAFSCM_InitCallBackState(struct afs_server *server)
28 {
29 	struct list_head callbacks;
30 
31 	_enter("%p", server);
32 
33 	INIT_LIST_HEAD(&callbacks);
34 
35 	/* transfer the callback list from the server to a temp holding area */
36 	spin_lock(&server->cb_lock);
37 
38 	list_add(&callbacks, &server->cb_promises);
39 	list_del_init(&server->cb_promises);
40 
41 	/* munch our way through the list, grabbing the inode, dropping all the
42 	 * locks and regetting them in the right order
43 	 */
44 	while (!list_empty(&callbacks)) {
45 		struct afs_vnode *vnode;
46 		struct inode *inode;
47 
48 		vnode = list_entry(callbacks.next, struct afs_vnode, cb_link);
49 		list_del_init(&vnode->cb_link);
50 
51 		/* try and grab the inode - may fail */
52 		inode = igrab(AFS_VNODE_TO_I(vnode));
53 		if (inode) {
54 			int release = 0;
55 
56 			spin_unlock(&server->cb_lock);
57 			spin_lock(&vnode->lock);
58 
59 			if (vnode->cb_server == server) {
60 				vnode->cb_server = NULL;
61 				afs_kafstimod_del_timer(&vnode->cb_timeout);
62 				spin_lock(&afs_cb_hash_lock);
63 				list_del_init(&vnode->cb_hash_link);
64 				spin_unlock(&afs_cb_hash_lock);
65 				release = 1;
66 			}
67 
68 			spin_unlock(&vnode->lock);
69 
70 			iput(inode);
71 			afs_put_server(server);
72 
73 			spin_lock(&server->cb_lock);
74 		}
75 	}
76 
77 	spin_unlock(&server->cb_lock);
78 
79 	_leave(" = 0");
80 	return 0;
81 } /* end SRXAFSCM_InitCallBackState() */
82 
83 /*****************************************************************************/
84 /*
85  * allow the fileserver to break callback promises
86  */
87 int SRXAFSCM_CallBack(struct afs_server *server, size_t count,
88 		      struct afs_callback callbacks[])
89 {
90 	_enter("%p,%u,", server, count);
91 
92 	for (; count > 0; callbacks++, count--) {
93 		struct afs_vnode *vnode = NULL;
94 		struct inode *inode = NULL;
95 		int valid = 0;
96 
97 		_debug("- Fid { vl=%08x n=%u u=%u }  CB { v=%u x=%u t=%u }",
98 		       callbacks->fid.vid,
99 		       callbacks->fid.vnode,
100 		       callbacks->fid.unique,
101 		       callbacks->version,
102 		       callbacks->expiry,
103 		       callbacks->type
104 		       );
105 
106 		/* find the inode for this fid */
107 		spin_lock(&afs_cb_hash_lock);
108 
109 		list_for_each_entry(vnode,
110 				    &afs_cb_hash(server, &callbacks->fid),
111 				    cb_hash_link) {
112 			if (memcmp(&vnode->fid, &callbacks->fid,
113 				   sizeof(struct afs_fid)) != 0)
114 				continue;
115 
116 			/* right vnode, but is it same server? */
117 			if (vnode->cb_server != server)
118 				break; /* no */
119 
120 			/* try and nail the inode down */
121 			inode = igrab(AFS_VNODE_TO_I(vnode));
122 			break;
123 		}
124 
125 		spin_unlock(&afs_cb_hash_lock);
126 
127 		if (inode) {
128 			/* we've found the record for this vnode */
129 			spin_lock(&vnode->lock);
130 			if (vnode->cb_server == server) {
131 				/* the callback _is_ on the calling server */
132 				vnode->cb_server = NULL;
133 				valid = 1;
134 
135 				afs_kafstimod_del_timer(&vnode->cb_timeout);
136 				vnode->flags |= AFS_VNODE_CHANGED;
137 
138 				spin_lock(&server->cb_lock);
139 				list_del_init(&vnode->cb_link);
140 				spin_unlock(&server->cb_lock);
141 
142 				spin_lock(&afs_cb_hash_lock);
143 				list_del_init(&vnode->cb_hash_link);
144 				spin_unlock(&afs_cb_hash_lock);
145 			}
146 			spin_unlock(&vnode->lock);
147 
148 			if (valid) {
149 				invalidate_remote_inode(inode);
150 				afs_put_server(server);
151 			}
152 			iput(inode);
153 		}
154 	}
155 
156 	_leave(" = 0");
157 	return 0;
158 } /* end SRXAFSCM_CallBack() */
159 
160 /*****************************************************************************/
161 /*
162  * allow the fileserver to see if the cache manager is still alive
163  */
164 int SRXAFSCM_Probe(struct afs_server *server)
165 {
166 	_debug("SRXAFSCM_Probe(%p)\n", server);
167 	return 0;
168 } /* end SRXAFSCM_Probe() */
169