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  * 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 }
  82
  83 /*
  84  * allow the fileserver to break callback promises
  85  */
  86 int SRXAFSCM_CallBack(struct afs_server *server, size_t count,
  87                       struct afs_callback callbacks[])
  88 {
  89         _enter("%p,%u,", server, count);
  90
  91         for (; count > 0; callbacks++, count--) {
  92                 struct afs_vnode *vnode = NULL;
  93                 struct inode *inode = NULL;
  94                 int valid = 0;
  95
  96                 _debug("- Fid { vl=%08x n=%u u=%u }  CB { v=%u x=%u t=%u }",
  97                        callbacks->fid.vid,
  98                        callbacks->fid.vnode,
  99                        callbacks->fid.unique,
 100                        callbacks->version,
 101                        callbacks->expiry,
 102                        callbacks->type
 103                        );
 104
 105                 /* find the inode for this fid */
 106                 spin_lock(&afs_cb_hash_lock);
 107
 108                 list_for_each_entry(vnode,
 109                                     &afs_cb_hash(server, &callbacks->fid),
 110                                     cb_hash_link) {
 111                         if (memcmp(&vnode->fid, &callbacks->fid,
 112                                    sizeof(struct afs_fid)) != 0)
 113                                 continue;
 114
 115                         /* right vnode, but is it same server? */
 116                         if (vnode->cb_server != server)
 117                                 break; /* no */
 118
 119                         /* try and nail the inode down */
 120                         inode = igrab(AFS_VNODE_TO_I(vnode));
 121                         break;
 122                 }
 123
 124                 spin_unlock(&afs_cb_hash_lock);
 125
 126                 if (inode) {
 127                         /* we've found the record for this vnode */
 128                         spin_lock(&vnode->lock);
 129                         if (vnode->cb_server == server) {
 130                                 /* the callback _is_ on the calling server */
 131                                 vnode->cb_server = NULL;
 132                                 valid = 1;
 133
 134                                 afs_kafstimod_del_timer(&vnode->cb_timeout);
 135                                 vnode->flags |= AFS_VNODE_CHANGED;
 136
 137                                 spin_lock(&server->cb_lock);
 138                                 list_del_init(&vnode->cb_link);
 139                                 spin_unlock(&server->cb_lock);
 140
 141                                 spin_lock(&afs_cb_hash_lock);
 142                                 list_del_init(&vnode->cb_hash_link);
 143                                 spin_unlock(&afs_cb_hash_lock);
 144                         }
 145                         spin_unlock(&vnode->lock);
 146
 147                         if (valid) {
 148                                 invalidate_remote_inode(inode);
 149                                 afs_put_server(server);
 150                         }
 151                         iput(inode);
 152                 }
 153         }
 154
 155         _leave(" = 0");
 156         return 0;
 157 }
 158
 159 /*
 160  * allow the fileserver to see if the cache manager is still alive
 161  */
 162 int SRXAFSCM_Probe(struct afs_server *server)
 163 {
 164         _debug("SRXAFSCM_Probe(%p)\n", server);
 165         return 0;
 166 }