Commit f3f80148 authored by Jeff Layton's avatar Jeff Layton Committed by J. Bruce Fields
Browse files

nfsd: add the infrastructure to handle the cld upcall 



...and add a mechanism for switching between the "legacy" tracker and
the new one. The decision is made by looking to see whether the
v4recoverydir exists. If it does, then the legacy client tracker is
used.

If it's not, then the kernel will create a "cld" pipe in rpc_pipefs.
That pipe is used to talk to a daemon for handling the upcall.

Most of the data structures for the new client tracker are handled on a
per-namespace basis, so this upcall should be essentially ready for
containerization. For now however, nfsd just starts it by calling the
initialization and exit functions for init_net.

I'm making the assumption that at some point in the future we'll be able
to determine the net namespace from the nfs4_client. Until then, this
patch hardcodes init_net in those places. I've sprinkled some "FIXME"
comments around that code to attempt to make it clear where we'll need
to fix that up later.

Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 0ab628d8

fs/nfsd/nfs4recover.c

+443 −1
Original line number Diff line number Diff line 
/*

*  Copyright (c) 2004 The Regents of the University of Michigan.

*  Copyright (c) 2012 Jeff Layton <jlayton@redhat.com>

*  All rights reserved.

*

*  Andy Adamson <andros@citi.umich.edu>
@@ -36,10 +37,16 @@ 
#include <linux/namei.h>

#include <linux/crypto.h>

#include <linux/sched.h>

#include <linux/fs.h>

#include <net/net_namespace.h>

#include <linux/sunrpc/rpc_pipe_fs.h>

#include <linux/sunrpc/clnt.h>

#include <linux/nfsd/cld.h>



#include "nfsd.h"

#include "state.h"

#include "vfs.h"

#include "netns.h"



#define NFSDDBG_FACILITY                NFSDDBG_PROC
@@ -486,12 +493,447 @@ static struct nfsd4_client_tracking_ops nfsd4_legacy_tracking_ops = { 
	.grace_done	= nfsd4_recdir_purge_old,

};



/* Globals */

#define NFSD_PIPE_DIR		"nfsd"

#define NFSD_CLD_PIPE		"cld"



/* per-net-ns structure for holding cld upcall info */

struct cld_net {

	struct rpc_pipe		*cn_pipe;

	spinlock_t		 cn_lock;

	struct list_head	 cn_list;

	unsigned int		 cn_xid;

};



struct cld_upcall {

	struct list_head	 cu_list;

	struct cld_net		*cu_net;

	struct task_struct	*cu_task;

	struct cld_msg		 cu_msg;

};



static int

__cld_pipe_upcall(struct rpc_pipe *pipe, struct cld_msg *cmsg)

{

	int ret;

	struct rpc_pipe_msg msg;



	memset(&msg, 0, sizeof(msg));

	msg.data = cmsg;

	msg.len = sizeof(*cmsg);



	/*

	 * Set task state before we queue the upcall. That prevents

	 * wake_up_process in the downcall from racing with schedule.

	 */

	set_current_state(TASK_UNINTERRUPTIBLE);

	ret = rpc_queue_upcall(pipe, &msg);

	if (ret < 0) {

		set_current_state(TASK_RUNNING);

		goto out;

	}



	schedule();

	set_current_state(TASK_RUNNING);



	if (msg.errno < 0)

		ret = msg.errno;

out:

	return ret;

}



static int

cld_pipe_upcall(struct rpc_pipe *pipe, struct cld_msg *cmsg)

{

	int ret;



	/*

	 * -EAGAIN occurs when pipe is closed and reopened while there are

	 *  upcalls queued.

	 */

	do {

		ret = __cld_pipe_upcall(pipe, cmsg);

	} while (ret == -EAGAIN);



	return ret;

}



static ssize_t

cld_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)

{

	struct cld_upcall *tmp, *cup;

	struct cld_msg *cmsg = (struct cld_msg *)src;

	uint32_t xid;

	struct nfsd_net *nn = net_generic(filp->f_dentry->d_sb->s_fs_info,

						nfsd_net_id);

	struct cld_net *cn = nn->cld_net;



	if (mlen != sizeof(*cmsg)) {

		dprintk("%s: got %lu bytes, expected %lu\n", __func__, mlen,

			sizeof(*cmsg));

		return -EINVAL;

	}



	/* copy just the xid so we can try to find that */

	if (copy_from_user(&xid, &cmsg->cm_xid, sizeof(xid)) != 0) {

		dprintk("%s: error when copying xid from userspace", __func__);

		return -EFAULT;

	}



	/* walk the list and find corresponding xid */

	cup = NULL;

	spin_lock(&cn->cn_lock);

	list_for_each_entry(tmp, &cn->cn_list, cu_list) {

		if (get_unaligned(&tmp->cu_msg.cm_xid) == xid) {

			cup = tmp;

			list_del_init(&cup->cu_list);

			break;

		}

	}

	spin_unlock(&cn->cn_lock);



	/* couldn't find upcall? */

	if (!cup) {

		dprintk("%s: couldn't find upcall -- xid=%u\n", __func__,

			cup->cu_msg.cm_xid);

		return -EINVAL;

	}



	if (copy_from_user(&cup->cu_msg, src, mlen) != 0)

		return -EFAULT;



	wake_up_process(cup->cu_task);

	return mlen;

}



static void

cld_pipe_destroy_msg(struct rpc_pipe_msg *msg)

{

	struct cld_msg *cmsg = msg->data;

	struct cld_upcall *cup = container_of(cmsg, struct cld_upcall,

						 cu_msg);



	/* errno >= 0 means we got a downcall */

	if (msg->errno >= 0)

		return;



	wake_up_process(cup->cu_task);

}



static const struct rpc_pipe_ops cld_upcall_ops = {

	.upcall		= rpc_pipe_generic_upcall,

	.downcall	= cld_pipe_downcall,

	.destroy_msg	= cld_pipe_destroy_msg,

};



static struct dentry *

nfsd4_cld_register_sb(struct super_block *sb, struct rpc_pipe *pipe)

{

	struct dentry *dir, *dentry;



	dir = rpc_d_lookup_sb(sb, NFSD_PIPE_DIR);

	if (dir == NULL)

		return ERR_PTR(-ENOENT);

	dentry = rpc_mkpipe_dentry(dir, NFSD_CLD_PIPE, NULL, pipe);

	dput(dir);

	return dentry;

}



static void

nfsd4_cld_unregister_sb(struct rpc_pipe *pipe)

{

	if (pipe->dentry)

		rpc_unlink(pipe->dentry);

}



static struct dentry *

nfsd4_cld_register_net(struct net *net, struct rpc_pipe *pipe)

{

	struct super_block *sb;

	struct dentry *dentry;



	sb = rpc_get_sb_net(net);

	if (!sb)

		return NULL;

	dentry = nfsd4_cld_register_sb(sb, pipe);

	rpc_put_sb_net(net);

	return dentry;

}



static void

nfsd4_cld_unregister_net(struct net *net, struct rpc_pipe *pipe)

{

	struct super_block *sb;



	sb = rpc_get_sb_net(net);

	if (sb) {

		nfsd4_cld_unregister_sb(pipe);

		rpc_put_sb_net(net);

	}

}



/* Initialize rpc_pipefs pipe for communication with client tracking daemon */

static int

nfsd4_init_cld_pipe(struct net *net)

{

	int ret;

	struct dentry *dentry;

	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	struct cld_net *cn;



	if (nn->cld_net)

		return 0;



	cn = kzalloc(sizeof(*cn), GFP_KERNEL);

	if (!cn) {

		ret = -ENOMEM;

		goto err;

	}



	cn->cn_pipe = rpc_mkpipe_data(&cld_upcall_ops, RPC_PIPE_WAIT_FOR_OPEN);

	if (IS_ERR(cn->cn_pipe)) {

		ret = PTR_ERR(cn->cn_pipe);

		goto err;

	}

	spin_lock_init(&cn->cn_lock);

	INIT_LIST_HEAD(&cn->cn_list);



	dentry = nfsd4_cld_register_net(net, cn->cn_pipe);

	if (IS_ERR(dentry)) {

		ret = PTR_ERR(dentry);

		goto err_destroy_data;

	}



	cn->cn_pipe->dentry = dentry;

	nn->cld_net = cn;

	return 0;



err_destroy_data:

	rpc_destroy_pipe_data(cn->cn_pipe);

err:

	kfree(cn);

	printk(KERN_ERR "NFSD: unable to create nfsdcld upcall pipe (%d)\n",

			ret);

	return ret;

}



static void

nfsd4_remove_cld_pipe(struct net *net)

{

	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	struct cld_net *cn = nn->cld_net;



	nfsd4_cld_unregister_net(net, cn->cn_pipe);

	rpc_destroy_pipe_data(cn->cn_pipe);

	kfree(nn->cld_net);

	nn->cld_net = NULL;

}



static struct cld_upcall *

alloc_cld_upcall(struct cld_net *cn)

{

	struct cld_upcall *new, *tmp;



	new = kzalloc(sizeof(*new), GFP_KERNEL);

	if (!new)

		return new;



	/* FIXME: hard cap on number in flight? */

restart_search:

	spin_lock(&cn->cn_lock);

	list_for_each_entry(tmp, &cn->cn_list, cu_list) {

		if (tmp->cu_msg.cm_xid == cn->cn_xid) {

			cn->cn_xid++;

			spin_unlock(&cn->cn_lock);

			goto restart_search;

		}

	}

	new->cu_task = current;

	new->cu_msg.cm_vers = CLD_UPCALL_VERSION;

	put_unaligned(cn->cn_xid++, &new->cu_msg.cm_xid);

	new->cu_net = cn;

	list_add(&new->cu_list, &cn->cn_list);

	spin_unlock(&cn->cn_lock);



	dprintk("%s: allocated xid %u\n", __func__, new->cu_msg.cm_xid);



	return new;

}



static void

free_cld_upcall(struct cld_upcall *victim)

{

	struct cld_net *cn = victim->cu_net;



	spin_lock(&cn->cn_lock);

	list_del(&victim->cu_list);

	spin_unlock(&cn->cn_lock);

	kfree(victim);

}



/* Ask daemon to create a new record */

static void

nfsd4_cld_create(struct nfs4_client *clp)

{

	int ret;

	struct cld_upcall *cup;

	/* FIXME: determine net from clp */

	struct nfsd_net *nn = net_generic(&init_net, nfsd_net_id);

	struct cld_net *cn = nn->cld_net;



	/* Don't upcall if it's already stored */

	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))

		return;



	cup = alloc_cld_upcall(cn);

	if (!cup) {

		ret = -ENOMEM;

		goto out_err;

	}



	cup->cu_msg.cm_cmd = Cld_Create;

	cup->cu_msg.cm_u.cm_name.cn_len = clp->cl_name.len;

	memcpy(cup->cu_msg.cm_u.cm_name.cn_id, clp->cl_name.data,

			clp->cl_name.len);



	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_msg);

	if (!ret) {

		ret = cup->cu_msg.cm_status;

		set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);

	}



	free_cld_upcall(cup);

out_err:

	if (ret)

		printk(KERN_ERR "NFSD: Unable to create client "

				"record on stable storage: %d\n", ret);

}



/* Ask daemon to create a new record */

static void

nfsd4_cld_remove(struct nfs4_client *clp)

{

	int ret;

	struct cld_upcall *cup;

	/* FIXME: determine net from clp */

	struct nfsd_net *nn = net_generic(&init_net, nfsd_net_id);

	struct cld_net *cn = nn->cld_net;



	/* Don't upcall if it's already removed */

	if (!test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))

		return;



	cup = alloc_cld_upcall(cn);

	if (!cup) {

		ret = -ENOMEM;

		goto out_err;

	}



	cup->cu_msg.cm_cmd = Cld_Remove;

	cup->cu_msg.cm_u.cm_name.cn_len = clp->cl_name.len;

	memcpy(cup->cu_msg.cm_u.cm_name.cn_id, clp->cl_name.data,

			clp->cl_name.len);



	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_msg);

	if (!ret) {

		ret = cup->cu_msg.cm_status;

		clear_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);

	}



	free_cld_upcall(cup);

out_err:

	if (ret)

		printk(KERN_ERR "NFSD: Unable to remove client "

				"record from stable storage: %d\n", ret);

}



/* Check for presence of a record, and update its timestamp */

static int

nfsd4_cld_check(struct nfs4_client *clp)

{

	int ret;

	struct cld_upcall *cup;

	/* FIXME: determine net from clp */

	struct nfsd_net *nn = net_generic(&init_net, nfsd_net_id);

	struct cld_net *cn = nn->cld_net;



	/* Don't upcall if one was already stored during this grace pd */

	if (test_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags))

		return 0;



	cup = alloc_cld_upcall(cn);

	if (!cup) {

		printk(KERN_ERR "NFSD: Unable to check client record on "

				"stable storage: %d\n", -ENOMEM);

		return -ENOMEM;

	}



	cup->cu_msg.cm_cmd = Cld_Check;

	cup->cu_msg.cm_u.cm_name.cn_len = clp->cl_name.len;

	memcpy(cup->cu_msg.cm_u.cm_name.cn_id, clp->cl_name.data,

			clp->cl_name.len);



	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_msg);

	if (!ret) {

		ret = cup->cu_msg.cm_status;

		set_bit(NFSD4_CLIENT_STABLE, &clp->cl_flags);

	}



	free_cld_upcall(cup);

	return ret;

}



static void

nfsd4_cld_grace_done(struct net *net, time_t boot_time)

{

	int ret;

	struct cld_upcall *cup;

	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	struct cld_net *cn = nn->cld_net;



	cup = alloc_cld_upcall(cn);

	if (!cup) {

		ret = -ENOMEM;

		goto out_err;

	}



	cup->cu_msg.cm_cmd = Cld_GraceDone;

	cup->cu_msg.cm_u.cm_gracetime = (int64_t)boot_time;

	ret = cld_pipe_upcall(cn->cn_pipe, &cup->cu_msg);

	if (!ret)

		ret = cup->cu_msg.cm_status;



	free_cld_upcall(cup);

out_err:

	if (ret)

		printk(KERN_ERR "NFSD: Unable to end grace period: %d\n", ret);

}



static struct nfsd4_client_tracking_ops nfsd4_cld_tracking_ops = {

	.init		= nfsd4_init_cld_pipe,

	.exit		= nfsd4_remove_cld_pipe,

	.create		= nfsd4_cld_create,

	.remove		= nfsd4_cld_remove,

	.check		= nfsd4_cld_check,

	.grace_done	= nfsd4_cld_grace_done,

};



int

nfsd4_client_tracking_init(struct net *net)

{

	int status;

	struct path path;



	client_tracking_ops = &nfsd4_legacy_tracking_ops;

	if (!client_tracking_ops) {

		client_tracking_ops = &nfsd4_cld_tracking_ops;

		status = kern_path(nfs4_recoverydir(), LOOKUP_FOLLOW, &path);

		if (!status) {

			if (S_ISDIR(path.dentry->d_inode->i_mode))

				client_tracking_ops =

						&nfsd4_legacy_tracking_ops;

			path_put(&path);

		}

	}



	status = client_tracking_ops->init(net);

	if (status) {

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