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/blkdev.h>
  31
  32 #include "blocklayout.h"
  33
  34 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
  35
  36 static void
  37 nfs4_encode_simple(__be32 *p, struct pnfs_block_volume *b)
  38 {
  39         int i;
  40
  41         *p++ = cpu_to_be32(1);
  42         *p++ = cpu_to_be32(b->type);
  43         *p++ = cpu_to_be32(b->simple.nr_sigs);
  44         for (i = 0; i < b->simple.nr_sigs; i++) {
  45                 p = xdr_encode_hyper(p, b->simple.sigs[i].offset);
  46                 p = xdr_encode_opaque(p, b->simple.sigs[i].sig,
  47                                          b->simple.sigs[i].sig_len);
  48         }
  49 }
  50
  51 dev_t
  52 bl_resolve_deviceid(struct nfs_server *server, struct pnfs_block_volume *b,
  53                 gfp_t gfp_mask)
  54 {
  55         struct net *net = server->nfs_client->cl_net;
  56         struct nfs_net *nn = net_generic(net, nfs_net_id);
  57         struct bl_dev_msg *reply = &nn->bl_mount_reply;
  58         struct bl_pipe_msg bl_pipe_msg;
  59         struct rpc_pipe_msg *msg = &bl_pipe_msg.msg;
  60         struct bl_msg_hdr *bl_msg;
  61         DECLARE_WAITQUEUE(wq, current);
  62         dev_t dev = 0;
  63         int rc;
  64
  65         dprintk("%s CREATING PIPEFS MESSAGE\n", __func__);
  66
  67         mutex_lock(&nn->bl_mutex);
  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                 goto out_unlock;
  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_unlock;
  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_free_data;
  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_free_data;
 101         }
 102
 103         dev = MKDEV(reply->major, reply->minor);
 104 out_free_data:
 105         kfree(msg->data);
 106 out_unlock:
 107         mutex_unlock(&nn->bl_mutex);
 108         return dev;
 109 }
 110
 111 static ssize_t bl_pipe_downcall(struct file *filp, const char __user *src,
 112                          size_t mlen)
 113 {
 114         struct nfs_net *nn = net_generic(file_inode(filp)->i_sb->s_fs_info,
 115                                          nfs_net_id);
 116
 117         if (mlen != sizeof (struct bl_dev_msg))
 118                 return -EINVAL;
 119
 120         if (copy_from_user(&nn->bl_mount_reply, src, mlen) != 0)
 121                 return -EFAULT;
 122
 123         wake_up(&nn->bl_wq);
 124
 125         return mlen;
 126 }
 127
 128 static void bl_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 129 {
 130         struct bl_pipe_msg *bl_pipe_msg =
 131                 container_of(msg, struct bl_pipe_msg, msg);
 132
 133         if (msg->errno >= 0)
 134                 return;
 135         wake_up(bl_pipe_msg->bl_wq);
 136 }
 137
 138 static const struct rpc_pipe_ops bl_upcall_ops = {
 139         .upcall         = rpc_pipe_generic_upcall,
 140         .downcall       = bl_pipe_downcall,
 141         .destroy_msg    = bl_pipe_destroy_msg,
 142 };
 143
 144 static struct dentry *nfs4blocklayout_register_sb(struct super_block *sb,
 145                                             struct rpc_pipe *pipe)
 146 {
 147         struct dentry *dir, *dentry;
 148
 149         dir = rpc_d_lookup_sb(sb, NFS_PIPE_DIRNAME);
 150         if (dir == NULL)
 151                 return ERR_PTR(-ENOENT);
 152         dentry = rpc_mkpipe_dentry(dir, "blocklayout", NULL, pipe);
 153         dput(dir);
 154         return dentry;
 155 }
 156
 157 static void nfs4blocklayout_unregister_sb(struct super_block *sb,
 158                                           struct rpc_pipe *pipe)
 159 {
 160         if (pipe->dentry)
 161                 rpc_unlink(pipe->dentry);
 162 }
 163
 164 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
 165                            void *ptr)
 166 {
 167         struct super_block *sb = ptr;
 168         struct net *net = sb->s_fs_info;
 169         struct nfs_net *nn = net_generic(net, nfs_net_id);
 170         struct dentry *dentry;
 171         int ret = 0;
 172
 173         if (!try_module_get(THIS_MODULE))
 174                 return 0;
 175
 176         if (nn->bl_device_pipe == NULL) {
 177                 module_put(THIS_MODULE);
 178                 return 0;
 179         }
 180
 181         switch (event) {
 182         case RPC_PIPEFS_MOUNT:
 183                 dentry = nfs4blocklayout_register_sb(sb, nn->bl_device_pipe);
 184                 if (IS_ERR(dentry)) {
 185                         ret = PTR_ERR(dentry);
 186                         break;
 187                 }
 188                 nn->bl_device_pipe->dentry = dentry;
 189                 break;
 190         case RPC_PIPEFS_UMOUNT:
 191                 if (nn->bl_device_pipe->dentry)
 192                         nfs4blocklayout_unregister_sb(sb, nn->bl_device_pipe);
 193                 break;
 194         default:
 195                 ret = -ENOTSUPP;
 196                 break;
 197         }
 198         module_put(THIS_MODULE);
 199         return ret;
 200 }
 201
 202 static struct notifier_block nfs4blocklayout_block = {
 203         .notifier_call = rpc_pipefs_event,
 204 };
 205
 206 static struct dentry *nfs4blocklayout_register_net(struct net *net,
 207                                                    struct rpc_pipe *pipe)
 208 {
 209         struct super_block *pipefs_sb;
 210         struct dentry *dentry;
 211
 212         pipefs_sb = rpc_get_sb_net(net);
 213         if (!pipefs_sb)
 214                 return NULL;
 215         dentry = nfs4blocklayout_register_sb(pipefs_sb, pipe);
 216         rpc_put_sb_net(net);
 217         return dentry;
 218 }
 219
 220 static void nfs4blocklayout_unregister_net(struct net *net,
 221                                            struct rpc_pipe *pipe)
 222 {
 223         struct super_block *pipefs_sb;
 224
 225         pipefs_sb = rpc_get_sb_net(net);
 226         if (pipefs_sb) {
 227                 nfs4blocklayout_unregister_sb(pipefs_sb, pipe);
 228                 rpc_put_sb_net(net);
 229         }
 230 }
 231
 232 static int nfs4blocklayout_net_init(struct net *net)
 233 {
 234         struct nfs_net *nn = net_generic(net, nfs_net_id);
 235         struct dentry *dentry;
 236
 237         mutex_init(&nn->bl_mutex);
 238         init_waitqueue_head(&nn->bl_wq);
 239         nn->bl_device_pipe = rpc_mkpipe_data(&bl_upcall_ops, 0);
 240         if (IS_ERR(nn->bl_device_pipe))
 241                 return PTR_ERR(nn->bl_device_pipe);
 242         dentry = nfs4blocklayout_register_net(net, nn->bl_device_pipe);
 243         if (IS_ERR(dentry)) {
 244                 rpc_destroy_pipe_data(nn->bl_device_pipe);
 245                 return PTR_ERR(dentry);
 246         }
 247         nn->bl_device_pipe->dentry = dentry;
 248         return 0;
 249 }
 250
 251 static void nfs4blocklayout_net_exit(struct net *net)
 252 {
 253         struct nfs_net *nn = net_generic(net, nfs_net_id);
 254
 255         nfs4blocklayout_unregister_net(net, nn->bl_device_pipe);
 256         rpc_destroy_pipe_data(nn->bl_device_pipe);
 257         nn->bl_device_pipe = NULL;
 258 }
 259
 260 static struct pernet_operations nfs4blocklayout_net_ops = {
 261         .init = nfs4blocklayout_net_init,
 262         .exit = nfs4blocklayout_net_exit,
 263 };
 264
 265 int __init bl_init_pipefs(void)
 266 {
 267         int ret;
 268
 269         ret = rpc_pipefs_notifier_register(&nfs4blocklayout_block);
 270         if (ret)
 271                 goto out;
 272         ret = register_pernet_subsys(&nfs4blocklayout_net_ops);
 273         if (ret)
 274                 goto out_unregister_notifier;
 275         return 0;
 276
 277 out_unregister_notifier:
 278         rpc_pipefs_notifier_unregister(&nfs4blocklayout_block);
 279 out:
 280         return ret;
 281 }
 282
 283 void bl_cleanup_pipefs(void)
 284 {
 285         rpc_pipefs_notifier_unregister(&nfs4blocklayout_block);
 286         unregister_pernet_subsys(&nfs4blocklayout_net_ops);
 287 }