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Commit 2571e173 authored by J. Bruce Fields's avatar J. Bruce Fields Committed by Greg Kroah-Hartman
Browse files

nfsd4: fix nfsdfs reference count loop 



[ Upstream commit 681370f4b00af0fcc65bbfb9f82de526ab7ceb0a ]

We don't drop the reference on the nfsdfs filesystem with
mntput(nn->nfsd_mnt) until nfsd_exit_net(), but that won't be called
until the nfsd module's unloaded, and we can't unload the module as long
as there's a reference on nfsdfs.  So this prevents module unloading.

Fixes: 2c830dd7 ("nfsd: persist nfsd filesystem across mounts")
Reported-and-Tested-by: default avatarLuo Xiaogang <lxgrxd@163.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 31ec38ec

fs/nfsd/nfs4state.c

+7 −1
Original line number Diff line number Diff line
@@ -7705,9 +7705,14 @@ nfs4_state_start_net(struct net *net) 
	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

	int ret;



	ret = nfs4_state_create_net(net);

	ret = get_nfsdfs(net);

	if (ret)

		return ret;

	ret = nfs4_state_create_net(net);

	if (ret) {

		mntput(nn->nfsd_mnt);

		return ret;

	}

	locks_start_grace(net, &nn->nfsd4_manager);

	nfsd4_client_tracking_init(net);

	if (nn->track_reclaim_completes && nn->reclaim_str_hashtbl_size == 0)
@@ -7776,6 +7781,7 @@ nfs4_state_shutdown_net(struct net *net) 


	nfsd4_client_tracking_exit(net);

	nfs4_state_destroy_net(net);

	mntput(nn->nfsd_mnt);

}



void

fs/nfsd/nfsctl.c

+12 −10
Original line number Diff line number Diff line
@@ -1424,6 +1424,18 @@ static struct file_system_type nfsd_fs_type = { 
};

MODULE_ALIAS_FS("nfsd");



int get_nfsdfs(struct net *net)

{

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

	struct vfsmount *mnt;



	mnt =  vfs_kern_mount(&nfsd_fs_type, SB_KERNMOUNT, "nfsd", NULL);

	if (IS_ERR(mnt))

		return PTR_ERR(mnt);

	nn->nfsd_mnt = mnt;

	return 0;

}



#ifdef CONFIG_PROC_FS

static int create_proc_exports_entry(void)

{
@@ -1452,7 +1464,6 @@ unsigned int nfsd_net_id; 
static __net_init int nfsd_init_net(struct net *net)

{

	int retval;

	struct vfsmount *mnt;

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



	retval = nfsd_export_init(net);
@@ -1479,16 +1490,8 @@ static __net_init int nfsd_init_net(struct net *net) 
	init_waitqueue_head(&nn->ntf_wq);

	seqlock_init(&nn->boot_lock);



	mnt =  vfs_kern_mount(&nfsd_fs_type, SB_KERNMOUNT, "nfsd", NULL);

	if (IS_ERR(mnt)) {

		retval = PTR_ERR(mnt);

		goto out_mount_err;

	}

	nn->nfsd_mnt = mnt;

	return 0;



out_mount_err:

	nfsd_reply_cache_shutdown(nn);

out_drc_error:

	nfsd_idmap_shutdown(net);

out_idmap_error:
@@ -1501,7 +1504,6 @@ static __net_exit void nfsd_exit_net(struct net *net) 
{

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



	mntput(nn->nfsd_mnt);

	nfsd_reply_cache_shutdown(nn);

	nfsd_idmap_shutdown(net);

	nfsd_export_shutdown(net);

fs/nfsd/nfsd.h

+3 −0
Original line number Diff line number Diff line
@@ -87,6 +87,8 @@ int nfsd_pool_stats_release(struct inode *, struct file *); 


void		nfsd_destroy(struct net *net);



int get_nfsdfs(struct net *);



struct nfsdfs_client {

	struct kref cl_ref;

	void (*cl_release)(struct kref *kref);
@@ -97,6 +99,7 @@ struct dentry *nfsd_client_mkdir(struct nfsd_net *nn, 
		struct nfsdfs_client *ncl, u32 id, const struct tree_descr *);

void nfsd_client_rmdir(struct dentry *dentry);





#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)

#ifdef CONFIG_NFSD_V2_ACL

extern const struct svc_version nfsd_acl_version2;