fs/nfs/blocklayout/rpc_pipefs.c

   1 /*
   2  *  Copyright (c) 2006,2007 The Regents of the University of Michigan.
   3  *  All rights reserved.
   4  *
   5  *  Andy Adamson <andros@citi.umich.edu>
   6  *  Fred Isaman <iisaman@umich.edu>
   7  *
   8  * permission is granted to use, copy, create derivative works and
   9  * redistribute this software and such derivative works for any purpose,
  10  * so long as the name of the university of michigan is not used in
  11  * any advertising or publicity pertaining to the use or distribution
  12  * of this software without specific, written prior authorization.  if
  13  * the above copyright notice or any other identification of the
  14  * university of michigan is included in any copy of any portion of
  15  * this software, then the disclaimer below must also be included.
  16  *
  17  * this software is provided as is, without representation from the
  18  * university of michigan as to its fitness for any purpose, and without
  19  * warranty by the university of michigan of any kind, either express
  20  * or implied, including without limitation the implied warranties of
  21  * merchantability and fitness for a particular purpose.  the regents
  22  * of the university of michigan shall not be liable for any damages,
  23  * including special, indirect, incidental, or consequential damages,
  24  * with respect to any claim arising out or in connection with the use
  25  * of the software, even if it has been or is hereafter advised of the
  26  * possibility of such damages.
  27  */
  28
  29 #include <linux/module.h>
  30 #include <linux/genhd.h>
  31 #include <linux/blkdev.h>
  32
  33 #include "blocklayout.h"
  34
  35 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
  36
  37 static void
  38 nfs4_encode_simple(__be32 *p, struct pnfs_block_volume *b)
  39 {
  40         int i;
  41
  42         *p++ = cpu_to_be32(1);
  43         *p++ = cpu_to_be32(b->type);
  44         *p++ = cpu_to_be32(b->simple.nr_sigs);
  45         for (i = 0; i < b->simple.nr_sigs; i++) {
  46                 p = xdr_encode_hyper(p, b->simple.sigs[i].offset);
  47                 p = xdr_encode_opaque(p, b->simple.sigs[i].sig,
  48                                          b->simple.sigs[i].sig_len);
  49         }
  50 }
  51
  52 dev_t
  53 bl_resolve_deviceid(struct nfs_server *server, struct pnfs_block_volume *b,
  54                 gfp_t gfp_mask)
  55 {
  56         struct net *net = server->nfs_client->cl_net;
  57         struct nfs_net *nn = net_generic(net, nfs_net_id);
  58         struct bl_dev_msg *reply = &nn->bl_mount_reply;
  59         struct bl_pipe_msg bl_pipe_msg;
  60         struct rpc_pipe_msg *msg = &bl_pipe_msg.msg;
  61         struct bl_msg_hdr *bl_msg;
  62         DECLARE_WAITQUEUE(wq, current);
  63         dev_t dev = 0;
  64         int rc;
  65
  66         dprintk("%s CREATING PIPEFS MESSAGE\n", __func__);
  67
  68         mutex_lock(&nn->bl_mutex);
  69         bl_pipe_msg.bl_wq = &nn->bl_wq;
  70
  71         b->simple.len += 4;     /* single volume */
  72         if (b->simple.len > PAGE_SIZE)
  73                 goto out_unlock;
  74
  75         memset(msg, 0, sizeof(*msg));
  76         msg->len = sizeof(*bl_msg) + b->simple.len;
  77         msg->data = kzalloc(msg->len, gfp_mask);
  78         if (!msg->data)
  79                 goto out_free_data;
  80
  81         bl_msg = msg->data;
  82         bl_msg->type = BL_DEVICE_MOUNT,
  83         bl_msg->totallen = b->simple.len;
  84         nfs4_encode_simple(msg->data + sizeof(*bl_msg), b);
  85
  86         dprintk("%s CALLING USERSPACE DAEMON\n", __func__);
  87         add_wait_queue(&nn->bl_wq, &wq);
  88         rc = rpc_queue_upcall(nn->bl_device_pipe, msg);
  89         if (rc < 0) {
  90                 remove_wait_queue(&nn->bl_wq, &wq);
  91                 goto out_free_data;
  92         }
  93
  94         set_current_state(TASK_UNINTERRUPTIBLE);
  95         schedule();
  96         remove_wait_queue(&nn->bl_wq, &wq);
  97
  98         if (reply->status != BL_DEVICE_REQUEST_PROC) {
  99                 printk(KERN_WARNING "%s failed to decode device: %d\n",
 100                         __func__, reply->status);
 101                 goto out_free_data;
 102         }
 103
 104         dev = MKDEV(reply->major, reply->minor);
 105 out_free_data:
 106         kfree(msg->data);
 107 out_unlock:
 108         mutex_unlock(&nn->bl_mutex);
 109         return dev;
 110 }
 111
 112 static ssize_t bl_pipe_downcall(struct file *filp, const char __user *src,
 113                          size_t mlen)
 114 {
 115         struct nfs_net *nn = net_generic(file_inode(filp)->i_sb->s_fs_info,
 116                                          nfs_net_id);
 117
 118         if (mlen != sizeof (struct bl_dev_msg))
 119                 return -EINVAL;
 120
 121         if (copy_from_user(&nn->bl_mount_reply, src, mlen) != 0)
 122                 return -EFAULT;
 123
 124         wake_up(&nn->bl_wq);
 125
 126         return mlen;
 127 }
 128
 129 static void bl_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 130 {
 131         struct bl_pipe_msg *bl_pipe_msg =
 132                 container_of(msg, struct bl_pipe_msg, msg);
 133
 134         if (msg->errno >= 0)
 135                 return;
 136         wake_up(bl_pipe_msg->bl_wq);
 137 }
 138
 139 static const struct rpc_pipe_ops bl_upcall_ops = {
 140         .upcall         = rpc_pipe_generic_upcall,
 141         .downcall       = bl_pipe_downcall,
 142         .destroy_msg    = bl_pipe_destroy_msg,
 143 };
 144
 145 static struct dentry *nfs4blocklayout_register_sb(struct super_block *sb,
 146                                             struct rpc_pipe *pipe)
 147 {
 148         struct dentry *dir, *dentry;
 149
 150         dir = rpc_d_lookup_sb(sb, NFS_PIPE_DIRNAME);
 151         if (dir == NULL)
 152                 return ERR_PTR(-ENOENT);
 153         dentry = rpc_mkpipe_dentry(dir, "blocklayout", NULL, pipe);
 154         dput(dir);
 155         return dentry;
 156 }
 157
 158 static void nfs4blocklayout_unregister_sb(struct super_block *sb,
 159                                           struct rpc_pipe *pipe)
 160 {
 161         if (pipe->dentry)
 162                 rpc_unlink(pipe->dentry);
 163 }
 164
 165 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
 166                            void *ptr)
 167 {
 168         struct super_block *sb = ptr;
 169         struct net *net = sb->s_fs_info;
 170         struct nfs_net *nn = net_generic(net, nfs_net_id);
 171         struct dentry *dentry;
 172         int ret = 0;
 173
 174         if (!try_module_get(THIS_MODULE))
 175                 return 0;
 176
 177         if (nn->bl_device_pipe == NULL) {
 178                 module_put(THIS_MODULE);
 179                 return 0;
 180         }
 181
 182         switch (event) {
 183         case RPC_PIPEFS_MOUNT:
 184                 dentry = nfs4blocklayout_register_sb(sb, nn->bl_device_pipe);
 185                 if (IS_ERR(dentry)) {
 186                         ret = PTR_ERR(dentry);
 187                         break;
 188                 }
 189                 nn->bl_device_pipe->dentry = dentry;
 190                 break;
 191         case RPC_PIPEFS_UMOUNT:
 192                 if (nn->bl_device_pipe->dentry)
 193                         nfs4blocklayout_unregister_sb(sb, nn->bl_device_pipe);
 194                 break;
 195         default:
 196                 ret = -ENOTSUPP;
 197                 break;
 198         }
 199         module_put(THIS_MODULE);
 200         return ret;
 201 }
 202
 203 static struct notifier_block nfs4blocklayout_block = {
 204         .notifier_call = rpc_pipefs_event,
 205 };
 206
 207 static struct dentry *nfs4blocklayout_register_net(struct net *net,
 208                                                    struct rpc_pipe *pipe)
 209 {
 210         struct super_block *pipefs_sb;
 211         struct dentry *dentry;
 212
 213         pipefs_sb = rpc_get_sb_net(net);
 214         if (!pipefs_sb)
 215                 return NULL;
 216         dentry = nfs4blocklayout_register_sb(pipefs_sb, pipe);
 217         rpc_put_sb_net(net);
 218         return dentry;
 219 }
 220
 221 static void nfs4blocklayout_unregister_net(struct net *net,
 222                                            struct rpc_pipe *pipe)
 223 {
 224         struct super_block *pipefs_sb;
 225
 226         pipefs_sb = rpc_get_sb_net(net);
 227         if (pipefs_sb) {
 228                 nfs4blocklayout_unregister_sb(pipefs_sb, pipe);
 229                 rpc_put_sb_net(net);
 230         }
 231 }
 232
 233 static int nfs4blocklayout_net_init(struct net *net)
 234 {
 235         struct nfs_net *nn = net_generic(net, nfs_net_id);
 236         struct dentry *dentry;
 237
 238         mutex_init(&nn->bl_mutex);
 239         init_waitqueue_head(&nn->bl_wq);
 240         nn->bl_device_pipe = rpc_mkpipe_data(&bl_upcall_ops, 0);
 241         if (IS_ERR(nn->bl_device_pipe))
 242                 return PTR_ERR(nn->bl_device_pipe);
 243         dentry = nfs4blocklayout_register_net(net, nn->bl_device_pipe);
 244         if (IS_ERR(dentry)) {
 245                 rpc_destroy_pipe_data(nn->bl_device_pipe);
 246                 return PTR_ERR(dentry);
 247         }
 248         nn->bl_device_pipe->dentry = dentry;
 249         return 0;
 250 }
 251
 252 static void nfs4blocklayout_net_exit(struct net *net)
 253 {
 254         struct nfs_net *nn = net_generic(net, nfs_net_id);
 255
 256         nfs4blocklayout_unregister_net(net, nn->bl_device_pipe);
 257         rpc_destroy_pipe_data(nn->bl_device_pipe);
 258         nn->bl_device_pipe = NULL;
 259 }
 260
 261 static struct pernet_operations nfs4blocklayout_net_ops = {
 262         .init = nfs4blocklayout_net_init,
 263         .exit = nfs4blocklayout_net_exit,
 264 };
 265
 266 int __init bl_init_pipefs(void)
 267 {
 268         int ret;
 269
 270         ret = rpc_pipefs_notifier_register(&nfs4blocklayout_block);
 271         if (ret)
 272                 goto out;
 273         ret = register_pernet_subsys(&nfs4blocklayout_net_ops);
 274         if (ret)
 275                 goto out_unregister_notifier;
 276         return 0;
 277
 278 out_unregister_notifier:
 279         rpc_pipefs_notifier_unregister(&nfs4blocklayout_block);
 280 out:
 281         return ret;
 282 }
 283
 284 void __exit bl_cleanup_pipefs(void)
 285 {
 286         rpc_pipefs_notifier_unregister(&nfs4blocklayout_block);
 287         unregister_pernet_subsys(&nfs4blocklayout_net_ops);
 288 }