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         bl_pipe_msg.bl_wq = &nn->bl_wq;
  69
  70         b->simple.len += 4;     /* single volume */
  71         if (b->simple.len > PAGE_SIZE)
  72                 return -EIO;
  73
  74         memset(msg, 0, sizeof(*msg));
  75         msg->len = sizeof(*bl_msg) + b->simple.len;
  76         msg->data = kzalloc(msg->len, gfp_mask);
  77         if (!msg->data)
  78                 goto out;
  79
  80         bl_msg = msg->data;
  81         bl_msg->type = BL_DEVICE_MOUNT,
  82         bl_msg->totallen = b->simple.len;
  83         nfs4_encode_simple(msg->data + sizeof(*bl_msg), b);
  84
  85         dprintk("%s CALLING USERSPACE DAEMON\n", __func__);
  86         add_wait_queue(&nn->bl_wq, &wq);
  87         rc = rpc_queue_upcall(nn->bl_device_pipe, msg);
  88         if (rc < 0) {
  89                 remove_wait_queue(&nn->bl_wq, &wq);
  90                 goto out;
  91         }
  92
  93         set_current_state(TASK_UNINTERRUPTIBLE);
  94         schedule();
  95         remove_wait_queue(&nn->bl_wq, &wq);
  96
  97         if (reply->status != BL_DEVICE_REQUEST_PROC) {
  98                 printk(KERN_WARNING "%s failed to decode device: %d\n",
  99                         __func__, reply->status);
 100                 goto out;
 101         }
 102
 103         dev = MKDEV(reply->major, reply->minor);
 104 out:
 105         kfree(msg->data);
 106         return dev;
 107 }
 108
 109 static ssize_t bl_pipe_downcall(struct file *filp, const char __user *src,
 110                          size_t mlen)
 111 {
 112         struct nfs_net *nn = net_generic(filp->f_dentry->d_sb->s_fs_info,
 113                                          nfs_net_id);
 114
 115         if (mlen != sizeof (struct bl_dev_msg))
 116                 return -EINVAL;
 117
 118         if (copy_from_user(&nn->bl_mount_reply, src, mlen) != 0)
 119                 return -EFAULT;
 120
 121         wake_up(&nn->bl_wq);
 122
 123         return mlen;
 124 }
 125
 126 static void bl_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 127 {
 128         struct bl_pipe_msg *bl_pipe_msg =
 129                 container_of(msg, struct bl_pipe_msg, msg);
 130
 131         if (msg->errno >= 0)
 132                 return;
 133         wake_up(bl_pipe_msg->bl_wq);
 134 }
 135
 136 static const struct rpc_pipe_ops bl_upcall_ops = {
 137         .upcall         = rpc_pipe_generic_upcall,
 138         .downcall       = bl_pipe_downcall,
 139         .destroy_msg    = bl_pipe_destroy_msg,
 140 };
 141
 142 static struct dentry *nfs4blocklayout_register_sb(struct super_block *sb,
 143                                             struct rpc_pipe *pipe)
 144 {
 145         struct dentry *dir, *dentry;
 146
 147         dir = rpc_d_lookup_sb(sb, NFS_PIPE_DIRNAME);
 148         if (dir == NULL)
 149                 return ERR_PTR(-ENOENT);
 150         dentry = rpc_mkpipe_dentry(dir, "blocklayout", NULL, pipe);
 151         dput(dir);
 152         return dentry;
 153 }
 154
 155 static void nfs4blocklayout_unregister_sb(struct super_block *sb,
 156                                           struct rpc_pipe *pipe)
 157 {
 158         if (pipe->dentry)
 159                 rpc_unlink(pipe->dentry);
 160 }
 161
 162 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
 163                            void *ptr)
 164 {
 165         struct super_block *sb = ptr;
 166         struct net *net = sb->s_fs_info;
 167         struct nfs_net *nn = net_generic(net, nfs_net_id);
 168         struct dentry *dentry;
 169         int ret = 0;
 170
 171         if (!try_module_get(THIS_MODULE))
 172                 return 0;
 173
 174         if (nn->bl_device_pipe == NULL) {
 175                 module_put(THIS_MODULE);
 176                 return 0;
 177         }
 178
 179         switch (event) {
 180         case RPC_PIPEFS_MOUNT:
 181                 dentry = nfs4blocklayout_register_sb(sb, nn->bl_device_pipe);
 182                 if (IS_ERR(dentry)) {
 183                         ret = PTR_ERR(dentry);
 184                         break;
 185                 }
 186                 nn->bl_device_pipe->dentry = dentry;
 187                 break;
 188         case RPC_PIPEFS_UMOUNT:
 189                 if (nn->bl_device_pipe->dentry)
 190                         nfs4blocklayout_unregister_sb(sb, nn->bl_device_pipe);
 191                 break;
 192         default:
 193                 ret = -ENOTSUPP;
 194                 break;
 195         }
 196         module_put(THIS_MODULE);
 197         return ret;
 198 }
 199
 200 static struct notifier_block nfs4blocklayout_block = {
 201         .notifier_call = rpc_pipefs_event,
 202 };
 203
 204 static struct dentry *nfs4blocklayout_register_net(struct net *net,
 205                                                    struct rpc_pipe *pipe)
 206 {
 207         struct super_block *pipefs_sb;
 208         struct dentry *dentry;
 209
 210         pipefs_sb = rpc_get_sb_net(net);
 211         if (!pipefs_sb)
 212                 return NULL;
 213         dentry = nfs4blocklayout_register_sb(pipefs_sb, pipe);
 214         rpc_put_sb_net(net);
 215         return dentry;
 216 }
 217
 218 static void nfs4blocklayout_unregister_net(struct net *net,
 219                                            struct rpc_pipe *pipe)
 220 {
 221         struct super_block *pipefs_sb;
 222
 223         pipefs_sb = rpc_get_sb_net(net);
 224         if (pipefs_sb) {
 225                 nfs4blocklayout_unregister_sb(pipefs_sb, pipe);
 226                 rpc_put_sb_net(net);
 227         }
 228 }
 229
 230 static int nfs4blocklayout_net_init(struct net *net)
 231 {
 232         struct nfs_net *nn = net_generic(net, nfs_net_id);
 233         struct dentry *dentry;
 234
 235         init_waitqueue_head(&nn->bl_wq);
 236         nn->bl_device_pipe = rpc_mkpipe_data(&bl_upcall_ops, 0);
 237         if (IS_ERR(nn->bl_device_pipe))
 238                 return PTR_ERR(nn->bl_device_pipe);
 239         dentry = nfs4blocklayout_register_net(net, nn->bl_device_pipe);
 240         if (IS_ERR(dentry)) {
 241                 rpc_destroy_pipe_data(nn->bl_device_pipe);
 242                 return PTR_ERR(dentry);
 243         }
 244         nn->bl_device_pipe->dentry = dentry;
 245         return 0;
 246 }
 247
 248 static void nfs4blocklayout_net_exit(struct net *net)
 249 {
 250         struct nfs_net *nn = net_generic(net, nfs_net_id);
 251
 252         nfs4blocklayout_unregister_net(net, nn->bl_device_pipe);
 253         rpc_destroy_pipe_data(nn->bl_device_pipe);
 254         nn->bl_device_pipe = NULL;
 255 }
 256
 257 static struct pernet_operations nfs4blocklayout_net_ops = {
 258         .init = nfs4blocklayout_net_init,
 259         .exit = nfs4blocklayout_net_exit,
 260 };
 261
 262 int __init bl_init_pipefs(void)
 263 {
 264         int ret;
 265
 266         ret = rpc_pipefs_notifier_register(&nfs4blocklayout_block);
 267         if (ret)
 268                 goto out;
 269         ret = register_pernet_subsys(&nfs4blocklayout_net_ops);
 270         if (ret)
 271                 goto out_unregister_notifier;
 272         return 0;
 273
 274 out_unregister_notifier:
 275         rpc_pipefs_notifier_unregister(&nfs4blocklayout_block);
 276 out:
 277         return ret;
 278 }
 279
 280 void __exit bl_cleanup_pipefs(void)
 281 {
 282         rpc_pipefs_notifier_unregister(&nfs4blocklayout_block);
 283         unregister_pernet_subsys(&nfs4blocklayout_net_ops);
 284 }