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linux/fs/nfs/blocklayout/rpc_pipefs.c

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/*
* Copyright (c) 2006,2007 The Regents of the University of Michigan.
* All rights reserved.
*
* Andy Adamson <andros@citi.umich.edu>
* Fred Isaman <iisaman@umich.edu>
*
* permission is granted to use, copy, create derivative works and
* redistribute this software and such derivative works for any purpose,
* so long as the name of the university of michigan is not used in
* any advertising or publicity pertaining to the use or distribution
* of this software without specific, written prior authorization. if
* the above copyright notice or any other identification of the
* university of michigan is included in any copy of any portion of
* this software, then the disclaimer below must also be included.
*
* this software is provided as is, without representation from the
* university of michigan as to its fitness for any purpose, and without
* warranty by the university of michigan of any kind, either express
* or implied, including without limitation the implied warranties of
* merchantability and fitness for a particular purpose. the regents
* of the university of michigan shall not be liable for any damages,
* including special, indirect, incidental, or consequential damages,
* with respect to any claim arising out or in connection with the use
* of the software, even if it has been or is hereafter advised of the
* possibility of such damages.
*/
#include <linux/module.h>
#include <linux/genhd.h>
#include <linux/blkdev.h>
#include "blocklayout.h"
#define NFSDBG_FACILITY NFSDBG_PNFS_LD
static void
nfs4_encode_simple(__be32 *p, struct pnfs_block_volume *b)
{
int i;
*p++ = cpu_to_be32(1);
*p++ = cpu_to_be32(b->type);
*p++ = cpu_to_be32(b->simple.nr_sigs);
for (i = 0; i < b->simple.nr_sigs; i++) {
p = xdr_encode_hyper(p, b->simple.sigs[i].offset);
p = xdr_encode_opaque(p, b->simple.sigs[i].sig,
b->simple.sigs[i].sig_len);
}
}
dev_t
bl_resolve_deviceid(struct nfs_server *server, struct pnfs_block_volume *b,
gfp_t gfp_mask)
{
struct net *net = server->nfs_client->cl_net;
struct nfs_net *nn = net_generic(net, nfs_net_id);
struct bl_dev_msg *reply = &nn->bl_mount_reply;
struct bl_pipe_msg bl_pipe_msg;
struct rpc_pipe_msg *msg = &bl_pipe_msg.msg;
struct bl_msg_hdr *bl_msg;
DECLARE_WAITQUEUE(wq, current);
dev_t dev = 0;
int rc;
dprintk("%s CREATING PIPEFS MESSAGE\n", __func__);
mutex_lock(&nn->bl_mutex);
bl_pipe_msg.bl_wq = &nn->bl_wq;
b->simple.len += 4; /* single volume */
if (b->simple.len > PAGE_SIZE)
goto out_unlock;
memset(msg, 0, sizeof(*msg));
msg->len = sizeof(*bl_msg) + b->simple.len;
msg->data = kzalloc(msg->len, gfp_mask);
if (!msg->data)
goto out_free_data;
bl_msg = msg->data;
bl_msg->type = BL_DEVICE_MOUNT,
bl_msg->totallen = b->simple.len;
nfs4_encode_simple(msg->data + sizeof(*bl_msg), b);
dprintk("%s CALLING USERSPACE DAEMON\n", __func__);
add_wait_queue(&nn->bl_wq, &wq);
rc = rpc_queue_upcall(nn->bl_device_pipe, msg);
if (rc < 0) {
remove_wait_queue(&nn->bl_wq, &wq);
goto out_free_data;
}
set_current_state(TASK_UNINTERRUPTIBLE);
schedule();
remove_wait_queue(&nn->bl_wq, &wq);
if (reply->status != BL_DEVICE_REQUEST_PROC) {
printk(KERN_WARNING "%s failed to decode device: %d\n",
__func__, reply->status);
goto out_free_data;
}
dev = MKDEV(reply->major, reply->minor);
out_free_data:
kfree(msg->data);
out_unlock:
mutex_unlock(&nn->bl_mutex);
return dev;
}
static ssize_t bl_pipe_downcall(struct file *filp, const char __user *src,
size_t mlen)
{
struct nfs_net *nn = net_generic(file_inode(filp)->i_sb->s_fs_info,
nfs_net_id);
if (mlen != sizeof (struct bl_dev_msg))
return -EINVAL;
if (copy_from_user(&nn->bl_mount_reply, src, mlen) != 0)
return -EFAULT;
wake_up(&nn->bl_wq);
return mlen;
}
static void bl_pipe_destroy_msg(struct rpc_pipe_msg *msg)
{
struct bl_pipe_msg *bl_pipe_msg =
container_of(msg, struct bl_pipe_msg, msg);
if (msg->errno >= 0)
return;
wake_up(bl_pipe_msg->bl_wq);
}
static const struct rpc_pipe_ops bl_upcall_ops = {
.upcall = rpc_pipe_generic_upcall,
.downcall = bl_pipe_downcall,
.destroy_msg = bl_pipe_destroy_msg,
};
static struct dentry *nfs4blocklayout_register_sb(struct super_block *sb,
struct rpc_pipe *pipe)
{
struct dentry *dir, *dentry;
dir = rpc_d_lookup_sb(sb, NFS_PIPE_DIRNAME);
if (dir == NULL)
return ERR_PTR(-ENOENT);
dentry = rpc_mkpipe_dentry(dir, "blocklayout", NULL, pipe);
dput(dir);
return dentry;
}
static void nfs4blocklayout_unregister_sb(struct super_block *sb,
struct rpc_pipe *pipe)
{
if (pipe->dentry)
rpc_unlink(pipe->dentry);
}
static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
void *ptr)
{
struct super_block *sb = ptr;
struct net *net = sb->s_fs_info;
struct nfs_net *nn = net_generic(net, nfs_net_id);
struct dentry *dentry;
int ret = 0;
if (!try_module_get(THIS_MODULE))
return 0;
if (nn->bl_device_pipe == NULL) {
module_put(THIS_MODULE);
return 0;
}
switch (event) {
case RPC_PIPEFS_MOUNT:
dentry = nfs4blocklayout_register_sb(sb, nn->bl_device_pipe);
if (IS_ERR(dentry)) {
ret = PTR_ERR(dentry);
break;
}
nn->bl_device_pipe->dentry = dentry;
break;
case RPC_PIPEFS_UMOUNT:
if (nn->bl_device_pipe->dentry)
nfs4blocklayout_unregister_sb(sb, nn->bl_device_pipe);
break;
default:
ret = -ENOTSUPP;
break;
}
module_put(THIS_MODULE);
return ret;
}
static struct notifier_block nfs4blocklayout_block = {
.notifier_call = rpc_pipefs_event,
};
static struct dentry *nfs4blocklayout_register_net(struct net *net,
struct rpc_pipe *pipe)
{
struct super_block *pipefs_sb;
struct dentry *dentry;
pipefs_sb = rpc_get_sb_net(net);
if (!pipefs_sb)
return NULL;
dentry = nfs4blocklayout_register_sb(pipefs_sb, pipe);
rpc_put_sb_net(net);
return dentry;
}
static void nfs4blocklayout_unregister_net(struct net *net,
struct rpc_pipe *pipe)
{
struct super_block *pipefs_sb;
pipefs_sb = rpc_get_sb_net(net);
if (pipefs_sb) {
nfs4blocklayout_unregister_sb(pipefs_sb, pipe);
rpc_put_sb_net(net);
}
}
static int nfs4blocklayout_net_init(struct net *net)
{
struct nfs_net *nn = net_generic(net, nfs_net_id);
struct dentry *dentry;
mutex_init(&nn->bl_mutex);
init_waitqueue_head(&nn->bl_wq);
nn->bl_device_pipe = rpc_mkpipe_data(&bl_upcall_ops, 0);
if (IS_ERR(nn->bl_device_pipe))
return PTR_ERR(nn->bl_device_pipe);
dentry = nfs4blocklayout_register_net(net, nn->bl_device_pipe);
if (IS_ERR(dentry)) {
rpc_destroy_pipe_data(nn->bl_device_pipe);
return PTR_ERR(dentry);
}
nn->bl_device_pipe->dentry = dentry;
return 0;
}
static void nfs4blocklayout_net_exit(struct net *net)
{
struct nfs_net *nn = net_generic(net, nfs_net_id);
nfs4blocklayout_unregister_net(net, nn->bl_device_pipe);
rpc_destroy_pipe_data(nn->bl_device_pipe);
nn->bl_device_pipe = NULL;
}
static struct pernet_operations nfs4blocklayout_net_ops = {
.init = nfs4blocklayout_net_init,
.exit = nfs4blocklayout_net_exit,
};
int __init bl_init_pipefs(void)
{
int ret;
ret = rpc_pipefs_notifier_register(&nfs4blocklayout_block);
if (ret)
goto out;
ret = register_pernet_subsys(&nfs4blocklayout_net_ops);
if (ret)
goto out_unregister_notifier;
return 0;
out_unregister_notifier:
rpc_pipefs_notifier_unregister(&nfs4blocklayout_block);
out:
return ret;
}
void bl_cleanup_pipefs(void)
{
rpc_pipefs_notifier_unregister(&nfs4blocklayout_block);
unregister_pernet_subsys(&nfs4blocklayout_net_ops);
}