[linux-2.6-block.git] / fs / nfs / nfs4super.c

/*
 * Copyright (c) 2012 Bryan Schumaker <bjschuma@netapp.com>
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/nfs_idmap.h>
#include <linux/nfs4_mount.h>
#include <linux/nfs_fs.h>
#include "internal.h"
#include "nfs4_fs.h"
#include "nfs.h"

#define NFSDBG_FACILITY		NFSDBG_VFS

static struct dentry *nfs4_remote_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *raw_data);
static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *raw_data);
static struct dentry *nfs4_remote_referral_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *raw_data);

static struct file_system_type nfs4_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "nfs4",
	.mount		= nfs_fs_mount,
	.kill_sb	= nfs_kill_super,
	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
};

static struct file_system_type nfs4_remote_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "nfs4",
	.mount		= nfs4_remote_mount,
	.kill_sb	= nfs_kill_super,
	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
};

static struct file_system_type nfs4_remote_referral_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "nfs4",
	.mount		= nfs4_remote_referral_mount,
	.kill_sb	= nfs_kill_super,
	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
};

struct file_system_type nfs4_referral_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "nfs4",
	.mount		= nfs4_referral_mount,
	.kill_sb	= nfs_kill_super,
	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
};

static const struct super_operations nfs4_sops = {
	.alloc_inode	= nfs_alloc_inode,
	.destroy_inode	= nfs_destroy_inode,
	.write_inode	= nfs4_write_inode,
	.put_super	= nfs_put_super,
	.statfs		= nfs_statfs,
	.evict_inode	= nfs4_evict_inode,
	.umount_begin	= nfs_umount_begin,
	.show_options	= nfs_show_options,
	.show_devname	= nfs_show_devname,
	.show_path	= nfs_show_path,
	.show_stats	= nfs_show_stats,
	.remount_fs	= nfs_remount,
};

struct nfs_subversion nfs_v4 = {
	.owner = THIS_MODULE,
	.nfs_fs   = &nfs4_fs_type,
	.rpc_vers = &nfs_version4,
	.rpc_ops  = &nfs_v4_clientops,
};

/*
 * Set up an NFS4 superblock
 */
static void nfs4_fill_super(struct super_block *sb,
			    struct nfs_mount_info *mount_info)
{
	sb->s_time_gran = 1;
	sb->s_op = &nfs4_sops;
	/*
	 * The VFS shouldn't apply the umask to mode bits. We will do
	 * so ourselves when necessary.
	 */
	sb->s_flags  |= MS_POSIXACL;
	sb->s_xattr = nfs4_xattr_handlers;
	nfs_initialise_sb(sb);
}

/*
 * Get the superblock for the NFS4 root partition
 */
static struct dentry *
nfs4_remote_mount(struct file_system_type *fs_type, int flags,
		  const char *dev_name, void *info)
{
	struct nfs_mount_info *mount_info = info;
	struct nfs_server *server;
	struct dentry *mntroot = ERR_PTR(-ENOMEM);

	mount_info->fill_super = nfs4_fill_super;
	mount_info->set_security = nfs_set_sb_security;

	/* Get a volume representation */
	server = nfs4_create_server(mount_info, &nfs_v4);
	if (IS_ERR(server)) {
		mntroot = ERR_CAST(server);
		goto out;
	}

	mntroot = nfs_fs_mount_common(server, flags, dev_name, mount_info, &nfs_v4);

out:
	return mntroot;
}

static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
		int flags, void *data, const char *hostname)
{
	struct vfsmount *root_mnt;
	char *root_devname;
	size_t len;

	len = strlen(hostname) + 5;
	root_devname = kmalloc(len, GFP_KERNEL);
	if (root_devname == NULL)
		return ERR_PTR(-ENOMEM);
	/* Does hostname needs to be enclosed in brackets? */
	if (strchr(hostname, ':'))
		snprintf(root_devname, len, "[%s]:/", hostname);
	else
		snprintf(root_devname, len, "%s:/", hostname);
	root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
	kfree(root_devname);
	return root_mnt;
}

struct nfs_referral_count {
	struct list_head list;
	const struct task_struct *task;
	unsigned int referral_count;
};

static LIST_HEAD(nfs_referral_count_list);
static DEFINE_SPINLOCK(nfs_referral_count_list_lock);

static struct nfs_referral_count *nfs_find_referral_count(void)
{
	struct nfs_referral_count *p;

	list_for_each_entry(p, &nfs_referral_count_list, list) {
		if (p->task == current)
			return p;
	}
	return NULL;
}

#define NFS_MAX_NESTED_REFERRALS 2

static int nfs_referral_loop_protect(void)
{
	struct nfs_referral_count *p, *new;
	int ret = -ENOMEM;

	new = kmalloc(sizeof(*new), GFP_KERNEL);
	if (!new)
		goto out;
	new->task = current;
	new->referral_count = 1;

	ret = 0;
	spin_lock(&nfs_referral_count_list_lock);
	p = nfs_find_referral_count();
	if (p != NULL) {
		if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
			ret = -ELOOP;
		else
			p->referral_count++;
	} else {
		list_add(&new->list, &nfs_referral_count_list);
		new = NULL;
	}
	spin_unlock(&nfs_referral_count_list_lock);
	kfree(new);
out:
	return ret;
}

static void nfs_referral_loop_unprotect(void)
{
	struct nfs_referral_count *p;

	spin_lock(&nfs_referral_count_list_lock);
	p = nfs_find_referral_count();
	p->referral_count--;
	if (p->referral_count == 0)
		list_del(&p->list);
	else
		p = NULL;
	spin_unlock(&nfs_referral_count_list_lock);
	kfree(p);
}

static struct dentry *nfs_follow_remote_path(struct vfsmount *root_mnt,
		const char *export_path)
{
	struct dentry *dentry;
	int err;

	if (IS_ERR(root_mnt))
		return ERR_CAST(root_mnt);

	err = nfs_referral_loop_protect();
	if (err) {
		mntput(root_mnt);
		return ERR_PTR(err);
	}

	dentry = mount_subtree(root_mnt, export_path);
	nfs_referral_loop_unprotect();

	return dentry;
}

struct dentry *nfs4_try_mount(int flags, const char *dev_name,
			      struct nfs_mount_info *mount_info,
			      struct nfs_subversion *nfs_mod)
{
	char *export_path;
	struct vfsmount *root_mnt;
	struct dentry *res;
	struct nfs_parsed_mount_data *data = mount_info->parsed;

	dfprintk(MOUNT, "--> nfs4_try_mount()\n");

	mount_info->fill_super = nfs4_fill_super;

	export_path = data->nfs_server.export_path;
	data->nfs_server.export_path = "/";
	root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, mount_info,
			data->nfs_server.hostname);
	data->nfs_server.export_path = export_path;

	res = nfs_follow_remote_path(root_mnt, export_path);

	dfprintk(MOUNT, "<-- nfs4_try_mount() = %ld%s\n",
			IS_ERR(res) ? PTR_ERR(res) : 0,
			IS_ERR(res) ? " [error]" : "");
	return res;
}

static struct dentry *
nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
			   const char *dev_name, void *raw_data)
{
	struct nfs_mount_info mount_info = {
		.fill_super = nfs4_fill_super,
		.set_security = nfs_clone_sb_security,
		.cloned = raw_data,
	};
	struct nfs_server *server;
	struct dentry *mntroot = ERR_PTR(-ENOMEM);

	dprintk("--> nfs4_referral_get_sb()\n");

	mount_info.mntfh = nfs_alloc_fhandle();
	if (mount_info.cloned == NULL || mount_info.mntfh == NULL)
		goto out;

	/* create a new volume representation */
	server = nfs4_create_referral_server(mount_info.cloned, mount_info.mntfh);
	if (IS_ERR(server)) {
		mntroot = ERR_CAST(server);
		goto out;
	}

	mntroot = nfs_fs_mount_common(server, flags, dev_name, &mount_info, &nfs_v4);
out:
	nfs_free_fhandle(mount_info.mntfh);
	return mntroot;
}

/*
 * Create an NFS4 server record on referral traversal
 */
static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
		int flags, const char *dev_name, void *raw_data)
{
	struct nfs_clone_mount *data = raw_data;
	char *export_path;
	struct vfsmount *root_mnt;
	struct dentry *res;

	dprintk("--> nfs4_referral_mount()\n");

	export_path = data->mnt_path;
	data->mnt_path = "/";

	root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
			flags, data, data->hostname);
	data->mnt_path = export_path;

	res = nfs_follow_remote_path(root_mnt, export_path);
	dprintk("<-- nfs4_referral_mount() = %ld%s\n",
			IS_ERR(res) ? PTR_ERR(res) : 0,
			IS_ERR(res) ? " [error]" : "");
	return res;
}


int __init init_nfs_v4(void)
{
	int err;

	err = nfs_idmap_init();
	if (err)
		goto out;

	err = nfs4_register_sysctl();
	if (err)
		goto out1;

	err = register_filesystem(&nfs4_fs_type);
	if (err < 0)
		goto out2;

	register_nfs_version(&nfs_v4);
	return 0;
out2:
	nfs4_unregister_sysctl();
out1:
	nfs_idmap_quit();
out:
	return err;
}

void exit_nfs_v4(void)
{
	unregister_nfs_version(&nfs_v4);
	unregister_filesystem(&nfs4_fs_type);
	nfs4_unregister_sysctl();
	nfs_idmap_quit();
}
Commit	Line	Data
129d1977 BS	1	/*
	2	* Copyright (c) 2012 Bryan Schumaker <bjschuma@netapp.com>
	3	*/
	4	#include <linux/init.h>
fbdefd64	5	#include <linux/module.h>
129d1977	6	#include <linux/nfs_idmap.h>
fbdefd64	7	#include <linux/nfs4_mount.h>
466bfe7f	8	#include <linux/nfs_fs.h>
fbdefd64	9	#include "internal.h"
466bfe7f	10	#include "nfs4_fs.h"
ab7017a3	11	#include "nfs.h"
129d1977	12
fbdefd64 BS	13	#define NFSDBG_FACILITY NFSDBG_VFS
	14
	15	static struct dentry nfs4_remote_mount(struct file_system_type fs_type,
	16	int flags, const char dev_name, void raw_data);
fbdefd64 BS	17	static struct dentry nfs4_referral_mount(struct file_system_type fs_type,
	18	int flags, const char dev_name, void raw_data);
	19	static struct dentry nfs4_remote_referral_mount(struct file_system_type fs_type,
	20	int flags, const char dev_name, void raw_data);
	21
	22	static struct file_system_type nfs4_fs_type = {
	23	.owner = THIS_MODULE,
	24	.name = "nfs4",
	25	.mount = nfs_fs_mount,
	26	.kill_sb = nfs_kill_super,
	27	.fs_flags = FS_RENAME_DOES_D_MOVE\|FS_REVAL_DOT\|FS_BINARY_MOUNTDATA,
	28	};
	29
	30	static struct file_system_type nfs4_remote_fs_type = {
	31	.owner = THIS_MODULE,
	32	.name = "nfs4",
	33	.mount = nfs4_remote_mount,
	34	.kill_sb = nfs_kill_super,
	35	.fs_flags = FS_RENAME_DOES_D_MOVE\|FS_REVAL_DOT\|FS_BINARY_MOUNTDATA,
	36	};
	37
fbdefd64 BS	38	static struct file_system_type nfs4_remote_referral_fs_type = {
	39	.owner = THIS_MODULE,
	40	.name = "nfs4",
	41	.mount = nfs4_remote_referral_mount,
	42	.kill_sb = nfs_kill_super,
	43	.fs_flags = FS_RENAME_DOES_D_MOVE\|FS_REVAL_DOT\|FS_BINARY_MOUNTDATA,
	44	};
	45
	46	struct file_system_type nfs4_referral_fs_type = {
	47	.owner = THIS_MODULE,
	48	.name = "nfs4",
	49	.mount = nfs4_referral_mount,
	50	.kill_sb = nfs_kill_super,
	51	.fs_flags = FS_RENAME_DOES_D_MOVE\|FS_REVAL_DOT\|FS_BINARY_MOUNTDATA,
	52	};
	53
	54	static const struct super_operations nfs4_sops = {
	55	.alloc_inode = nfs_alloc_inode,
	56	.destroy_inode = nfs_destroy_inode,
	57	.write_inode = nfs4_write_inode,
	58	.put_super = nfs_put_super,
	59	.statfs = nfs_statfs,
	60	.evict_inode = nfs4_evict_inode,
	61	.umount_begin = nfs_umount_begin,
	62	.show_options = nfs_show_options,
	63	.show_devname = nfs_show_devname,
	64	.show_path = nfs_show_path,
	65	.show_stats = nfs_show_stats,
	66	.remount_fs = nfs_remount,
	67	};
	68
ab7017a3 BS	69	struct nfs_subversion nfs_v4 = {
	70	.owner = THIS_MODULE,
	71	.nfs_fs = &nfs4_fs_type,
	72	.rpc_vers = &nfs_version4,
	73	.rpc_ops = &nfs_v4_clientops,
	74	};
	75
fbdefd64 BS	76	/*
	77	* Set up an NFS4 superblock
	78	*/
	79	static void nfs4_fill_super(struct super_block *sb,
	80	struct nfs_mount_info *mount_info)
	81	{
	82	sb->s_time_gran = 1;
	83	sb->s_op = &nfs4_sops;
	84	/*
	85	* The VFS shouldn't apply the umask to mode bits. We will do
	86	* so ourselves when necessary.
	87	*/
	88	sb->s_flags \|= MS_POSIXACL;
	89	sb->s_xattr = nfs4_xattr_handlers;
	90	nfs_initialise_sb(sb);
	91	}
	92
	93	/*
	94	* Get the superblock for the NFS4 root partition
	95	*/
	96	static struct dentry *
	97	nfs4_remote_mount(struct file_system_type *fs_type, int flags,
	98	const char dev_name, void info)
	99	{
	100	struct nfs_mount_info *mount_info = info;
	101	struct nfs_server *server;
	102	struct dentry *mntroot = ERR_PTR(-ENOMEM);
	103
	104	mount_info->fill_super = nfs4_fill_super;
	105	mount_info->set_security = nfs_set_sb_security;
	106
	107	/* Get a volume representation */
1179acc6	108	server = nfs4_create_server(mount_info, &nfs_v4);
fbdefd64 BS	109	if (IS_ERR(server)) {
	110	mntroot = ERR_CAST(server);
	111	goto out;
	112	}
	113
ab7017a3	114	mntroot = nfs_fs_mount_common(server, flags, dev_name, mount_info, &nfs_v4);
fbdefd64 BS	115
	116	out:
	117	return mntroot;
	118	}
	119
	120	static struct vfsmount nfs_do_root_mount(struct file_system_type fs_type,
	121	int flags, void data, const char hostname)
	122	{
	123	struct vfsmount *root_mnt;
	124	char *root_devname;
	125	size_t len;
	126
	127	len = strlen(hostname) + 5;
	128	root_devname = kmalloc(len, GFP_KERNEL);
	129	if (root_devname == NULL)
	130	return ERR_PTR(-ENOMEM);
	131	/* Does hostname needs to be enclosed in brackets? */
	132	if (strchr(hostname, ':'))
	133	snprintf(root_devname, len, "[%s]:/", hostname);
	134	else
	135	snprintf(root_devname, len, "%s:/", hostname);
	136	root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
	137	kfree(root_devname);
	138	return root_mnt;
	139	}
	140
	141	struct nfs_referral_count {
	142	struct list_head list;
	143	const struct task_struct *task;
	144	unsigned int referral_count;
	145	};
	146
	147	static LIST_HEAD(nfs_referral_count_list);
	148	static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
	149
	150	static struct nfs_referral_count *nfs_find_referral_count(void)
	151	{
	152	struct nfs_referral_count *p;
	153
	154	list_for_each_entry(p, &nfs_referral_count_list, list) {
	155	if (p->task == current)
	156	return p;
	157	}
	158	return NULL;
	159	}
	160
	161	#define NFS_MAX_NESTED_REFERRALS 2
	162
	163	static int nfs_referral_loop_protect(void)
	164	{
	165	struct nfs_referral_count p, new;
	166	int ret = -ENOMEM;
	167
	168	new = kmalloc(sizeof(*new), GFP_KERNEL);
	169	if (!new)
	170	goto out;
	171	new->task = current;
	172	new->referral_count = 1;
	173
	174	ret = 0;
	175	spin_lock(&nfs_referral_count_list_lock);
	176	p = nfs_find_referral_count();
	177	if (p != NULL) {
	178	if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
179	ret = -ELOOP;
180	else
181	p->referral_count++;
182	} else {
183	list_add(&new->list, &nfs_referral_count_list);
184	new = NULL;
185	}
186	spin_unlock(&nfs_referral_count_list_lock);
187	kfree(new);
188	out:
189	return ret;
190	}
191
192	static void nfs_referral_loop_unprotect(void)
193	{
194	struct nfs_referral_count *p;
195
196	spin_lock(&nfs_referral_count_list_lock);
197	p = nfs_find_referral_count();
198	p->referral_count--;
199	if (p->referral_count == 0)
200	list_del(&p->list);
201	else
202	p = NULL;
203	spin_unlock(&nfs_referral_count_list_lock);
204	kfree(p);
205	}
206
207	static struct dentry nfs_follow_remote_path(struct vfsmount root_mnt,
208	const char *export_path)
209	{
210	struct dentry *dentry;
211	int err;
212
213	if (IS_ERR(root_mnt))
214	return ERR_CAST(root_mnt);
215
216	err = nfs_referral_loop_protect();
217	if (err) {
218	mntput(root_mnt);
219	return ERR_PTR(err);
220	}
221
222	dentry = mount_subtree(root_mnt, export_path);
223	nfs_referral_loop_unprotect();
224
225	return dentry;
226	}
227
228	struct dentry nfs4_try_mount(int flags, const char dev_name,
ff9099f2 BS	229	struct nfs_mount_info *mount_info,
ff9099f2 BS	230	struct nfs_subversion *nfs_mod)
fbdefd64 BS	231	{
	232	char *export_path;
	233	struct vfsmount *root_mnt;
	234	struct dentry *res;
	235	struct nfs_parsed_mount_data *data = mount_info->parsed;
	236
	237	dfprintk(MOUNT, "--> nfs4_try_mount()\n");
	238
	239	mount_info->fill_super = nfs4_fill_super;
	240
	241	export_path = data->nfs_server.export_path;
	242	data->nfs_server.export_path = "/";
	243	root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, mount_info,
	244	data->nfs_server.hostname);
	245	data->nfs_server.export_path = export_path;
	246
	247	res = nfs_follow_remote_path(root_mnt, export_path);
	248
	249	dfprintk(MOUNT, "<-- nfs4_try_mount() = %ld%s\n",
	250	IS_ERR(res) ? PTR_ERR(res) : 0,
	251	IS_ERR(res) ? " [error]" : "");
	252	return res;
	253	}
	254
fbdefd64 BS	255	static struct dentry *
	256	nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
	257	const char dev_name, void raw_data)
	258	{
	259	struct nfs_mount_info mount_info = {
	260	.fill_super = nfs4_fill_super,
	261	.set_security = nfs_clone_sb_security,
	262	.cloned = raw_data,
	263	};
	264	struct nfs_server *server;
	265	struct dentry *mntroot = ERR_PTR(-ENOMEM);
	266
	267	dprintk("--> nfs4_referral_get_sb()\n");
	268
	269	mount_info.mntfh = nfs_alloc_fhandle();
	270	if (mount_info.cloned == NULL \|\| mount_info.mntfh == NULL)
	271	goto out;
	272
	273	/* create a new volume representation */
	274	server = nfs4_create_referral_server(mount_info.cloned, mount_info.mntfh);
	275	if (IS_ERR(server)) {
	276	mntroot = ERR_CAST(server);
	277	goto out;
	278	}
	279
ab7017a3	280	mntroot = nfs_fs_mount_common(server, flags, dev_name, &mount_info, &nfs_v4);
fbdefd64 BS	281	out:
	282	nfs_free_fhandle(mount_info.mntfh);
	283	return mntroot;
	284	}
	285
	286	/*
	287	* Create an NFS4 server record on referral traversal
	288	*/
	289	static struct dentry nfs4_referral_mount(struct file_system_type fs_type,
	290	int flags, const char dev_name, void raw_data)
	291	{
	292	struct nfs_clone_mount *data = raw_data;
	293	char *export_path;
	294	struct vfsmount *root_mnt;
	295	struct dentry *res;
	296
	297	dprintk("--> nfs4_referral_mount()\n");
	298
	299	export_path = data->mnt_path;
	300	data->mnt_path = "/";
	301
	302	root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
	303	flags, data, data->hostname);
	304	data->mnt_path = export_path;
	305
	306	res = nfs_follow_remote_path(root_mnt, export_path);
	307	dprintk("<-- nfs4_referral_mount() = %ld%s\n",
	308	IS_ERR(res) ? PTR_ERR(res) : 0,
	309	IS_ERR(res) ? " [error]" : "");
	310	return res;
	311	}
	312
	313
129d1977 BS	314	int __init init_nfs_v4(void)
	315	{
	316	int err;
	317
	318	err = nfs_idmap_init();
	319	if (err)
	320	goto out;
	321
466bfe7f BS	322	err = nfs4_register_sysctl();
	323	if (err)
	324	goto out1;
	325
fbdefd64 BS	326	err = register_filesystem(&nfs4_fs_type);
	327	if (err < 0)
	328	goto out2;
	329
ab7017a3	330	register_nfs_version(&nfs_v4);
129d1977	331	return 0;
fbdefd64 BS	332	out2:
fbdefd64 BS	333	nfs4_unregister_sysctl();
466bfe7f BS	334	out1:
466bfe7f BS	335	nfs_idmap_quit();
129d1977 BS	336	out:
	337	return err;
	338	}
	339
bb6e071f	340	void exit_nfs_v4(void)
129d1977	341	{
ab7017a3	342	unregister_nfs_version(&nfs_v4);
fbdefd64	343	unregister_filesystem(&nfs4_fs_type);
466bfe7f	344	nfs4_unregister_sysctl();
129d1977 BS	345	nfs_idmap_quit();
129d1977 BS	346	}