fs/afs/callback.c

   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() */