[deliverable/linux.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"

#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_xdev_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,
};

struct file_system_type nfs4_xdev_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "nfs4",
	.mount		= nfs4_xdev_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,
};

/*
 * 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->parsed, mount_info->mntfh);
	if (IS_ERR(server)) {
		mntroot = ERR_CAST(server);
		goto out;
	}

	mntroot = nfs_fs_mount_common(fs_type, server, flags, dev_name, mount_info);

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)
{
	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;
}

/*
 * Clone an NFS4 server record on xdev traversal (FSID-change)
 */
static struct dentry *
nfs4_xdev_mount(struct file_system_type *fs_type, int flags,
		 const char *dev_name, void *raw_data)
{
	struct nfs_mount_info mount_info = {
		.fill_super = nfs_clone_super,
		.set_security = nfs_clone_sb_security,
		.cloned = raw_data,
	};
	return nfs_xdev_mount_common(&nfs4_fs_type, flags, dev_name, &mount_info);
}

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(&nfs4_fs_type, server, flags, dev_name, &mount_info);
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;

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

void exit_nfs_v4(void)
{
	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"
129d1977	11
fbdefd64 BS	12	#define NFSDBG_FACILITY NFSDBG_VFS
	13
	14	static struct dentry nfs4_remote_mount(struct file_system_type fs_type,
	15	int flags, const char dev_name, void raw_data);
	16	static struct dentry nfs4_xdev_mount(struct file_system_type fs_type,
	17	int flags, const char dev_name, void raw_data);
	18	static struct dentry nfs4_referral_mount(struct file_system_type fs_type,
	19	int flags, const char dev_name, void raw_data);
	20	static struct dentry nfs4_remote_referral_mount(struct file_system_type fs_type,
	21	int flags, const char dev_name, void raw_data);
	22
	23	static struct file_system_type nfs4_fs_type = {
	24	.owner = THIS_MODULE,
	25	.name = "nfs4",
	26	.mount = nfs_fs_mount,
	27	.kill_sb = nfs_kill_super,
	28	.fs_flags = FS_RENAME_DOES_D_MOVE\|FS_REVAL_DOT\|FS_BINARY_MOUNTDATA,
	29	};
	30
	31	static struct file_system_type nfs4_remote_fs_type = {
	32	.owner = THIS_MODULE,
	33	.name = "nfs4",
	34	.mount = nfs4_remote_mount,
	35	.kill_sb = nfs_kill_super,
	36	.fs_flags = FS_RENAME_DOES_D_MOVE\|FS_REVAL_DOT\|FS_BINARY_MOUNTDATA,
	37	};
	38
	39	struct file_system_type nfs4_xdev_fs_type = {
	40	.owner = THIS_MODULE,
	41	.name = "nfs4",
	42	.mount = nfs4_xdev_mount,
	43	.kill_sb = nfs_kill_super,
	44	.fs_flags = FS_RENAME_DOES_D_MOVE\|FS_REVAL_DOT\|FS_BINARY_MOUNTDATA,
	45	};
	46
	47	static struct file_system_type nfs4_remote_referral_fs_type = {
	48	.owner = THIS_MODULE,
	49	.name = "nfs4",
	50	.mount = nfs4_remote_referral_mount,
	51	.kill_sb = nfs_kill_super,
	52	.fs_flags = FS_RENAME_DOES_D_MOVE\|FS_REVAL_DOT\|FS_BINARY_MOUNTDATA,
	53	};
	54
	55	struct file_system_type nfs4_referral_fs_type = {
	56	.owner = THIS_MODULE,
	57	.name = "nfs4",
	58	.mount = nfs4_referral_mount,
	59	.kill_sb = nfs_kill_super,
	60	.fs_flags = FS_RENAME_DOES_D_MOVE\|FS_REVAL_DOT\|FS_BINARY_MOUNTDATA,
	61	};
	62
	63	static const struct super_operations nfs4_sops = {
	64	.alloc_inode = nfs_alloc_inode,
	65	.destroy_inode = nfs_destroy_inode,
	66	.write_inode = nfs4_write_inode,
	67	.put_super = nfs_put_super,
	68	.statfs = nfs_statfs,
	69	.evict_inode = nfs4_evict_inode,
	70	.umount_begin = nfs_umount_begin,
	71	.show_options = nfs_show_options,
	72	.show_devname = nfs_show_devname,
	73	.show_path = nfs_show_path,
	74	.show_stats = nfs_show_stats,
	75	.remount_fs = nfs_remount,
76	};
77
78	/*
79	* Set up an NFS4 superblock
80	*/
81	static void nfs4_fill_super(struct super_block *sb,
82	struct nfs_mount_info *mount_info)
83	{
84	sb->s_time_gran = 1;
85	sb->s_op = &nfs4_sops;
86	/*
87	* The VFS shouldn't apply the umask to mode bits. We will do
88	* so ourselves when necessary.
89	*/
90	sb->s_flags \|= MS_POSIXACL;
91	sb->s_xattr = nfs4_xattr_handlers;
92	nfs_initialise_sb(sb);
93	}
94
95	/*
96	* Get the superblock for the NFS4 root partition
97	*/
98	static struct dentry *
99	nfs4_remote_mount(struct file_system_type *fs_type, int flags,
100	const char dev_name, void info)
101	{
102	struct nfs_mount_info *mount_info = info;
103	struct nfs_server *server;
104	struct dentry *mntroot = ERR_PTR(-ENOMEM);
105
106	mount_info->fill_super = nfs4_fill_super;
107	mount_info->set_security = nfs_set_sb_security;
108
109	/* Get a volume representation */
110	server = nfs4_create_server(mount_info->parsed, mount_info->mntfh);
111	if (IS_ERR(server)) {
112	mntroot = ERR_CAST(server);
113	goto out;
114	}
115
116	mntroot = nfs_fs_mount_common(fs_type, server, flags, dev_name, mount_info);
117
118	out:
119	return mntroot;
120	}
121
122	static struct vfsmount nfs_do_root_mount(struct file_system_type fs_type,
123	int flags, void data, const char hostname)
124	{
125	struct vfsmount *root_mnt;
126	char *root_devname;
127	size_t len;
128
129	len = strlen(hostname) + 5;
130	root_devname = kmalloc(len, GFP_KERNEL);
131	if (root_devname == NULL)
132	return ERR_PTR(-ENOMEM);
133	/* Does hostname needs to be enclosed in brackets? */
134	if (strchr(hostname, ':'))
135	snprintf(root_devname, len, "[%s]:/", hostname);
136	else
137	snprintf(root_devname, len, "%s:/", hostname);
138	root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
139	kfree(root_devname);
140	return root_mnt;
141	}
142
143	struct nfs_referral_count {
144	struct list_head list;
145	const struct task_struct *task;
146	unsigned int referral_count;
147	};
148
149	static LIST_HEAD(nfs_referral_count_list);
150	static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
151
152	static struct nfs_referral_count *nfs_find_referral_count(void)
153	{
154	struct nfs_referral_count *p;
155
156	list_for_each_entry(p, &nfs_referral_count_list, list) {
157	if (p->task == current)
158	return p;
159	}
160	return NULL;
161	}
162
163	#define NFS_MAX_NESTED_REFERRALS 2
164
165	static int nfs_referral_loop_protect(void)
166	{
167	struct nfs_referral_count p, new;
168	int ret = -ENOMEM;
169
170	new = kmalloc(sizeof(*new), GFP_KERNEL);
171	if (!new)
172	goto out;
173	new->task = current;
174	new->referral_count = 1;
175
176	ret = 0;
177	spin_lock(&nfs_referral_count_list_lock);
178	p = nfs_find_referral_count();
179	if (p != NULL) {
180	if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
181	ret = -ELOOP;
182	else
183	p->referral_count++;
184	} else {
185	list_add(&new->list, &nfs_referral_count_list);
186	new = NULL;
187	}
188	spin_unlock(&nfs_referral_count_list_lock);
189	kfree(new);
190	out:
191	return ret;
192	}
193
194	static void nfs_referral_loop_unprotect(void)
195	{
196	struct nfs_referral_count *p;
197
198	spin_lock(&nfs_referral_count_list_lock);
199	p = nfs_find_referral_count();
200	p->referral_count--;
201	if (p->referral_count == 0)
202	list_del(&p->list);
203	else
204	p = NULL;
205	spin_unlock(&nfs_referral_count_list_lock);
206	kfree(p);
207	}
208
209	static struct dentry nfs_follow_remote_path(struct vfsmount root_mnt,
210	const char *export_path)
211	{
212	struct dentry *dentry;
213	int err;
214
215	if (IS_ERR(root_mnt))
216	return ERR_CAST(root_mnt);
217
218	err = nfs_referral_loop_protect();
219	if (err) {
220	mntput(root_mnt);
221	return ERR_PTR(err);
222	}
223
224	dentry = mount_subtree(root_mnt, export_path);
225	nfs_referral_loop_unprotect();
226
227	return dentry;
228	}
229
230	struct dentry nfs4_try_mount(int flags, const char dev_name,
231	struct nfs_mount_info *mount_info)
232	{
233	char *export_path;
234	struct vfsmount *root_mnt;
235	struct dentry *res;
236	struct nfs_parsed_mount_data *data = mount_info->parsed;
237
238	dfprintk(MOUNT, "--> nfs4_try_mount()\n");
239
240	mount_info->fill_super = nfs4_fill_super;
241
242	export_path = data->nfs_server.export_path;
243	data->nfs_server.export_path = "/";
244	root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, mount_info,
245	data->nfs_server.hostname);
246	data->nfs_server.export_path = export_path;
247
248	res = nfs_follow_remote_path(root_mnt, export_path);
249
250	dfprintk(MOUNT, "<-- nfs4_try_mount() = %ld%s\n",
251	IS_ERR(res) ? PTR_ERR(res) : 0,
252	IS_ERR(res) ? " [error]" : "");
253	return res;
254	}
255
256	/*
257	* Clone an NFS4 server record on xdev traversal (FSID-change)
258	*/
259	static struct dentry *
260	nfs4_xdev_mount(struct file_system_type *fs_type, int flags,
261	const char dev_name, void raw_data)
262	{
263	struct nfs_mount_info mount_info = {
264	.fill_super = nfs_clone_super,
265	.set_security = nfs_clone_sb_security,
266	.cloned = raw_data,
267	};
268	return nfs_xdev_mount_common(&nfs4_fs_type, flags, dev_name, &mount_info);
269	}
270
271	static struct dentry *
272	nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
273	const char dev_name, void raw_data)
274	{
275	struct nfs_mount_info mount_info = {
276	.fill_super = nfs4_fill_super,
277	.set_security = nfs_clone_sb_security,
278	.cloned = raw_data,
279	};
280	struct nfs_server *server;
281	struct dentry *mntroot = ERR_PTR(-ENOMEM);
282
283	dprintk("--> nfs4_referral_get_sb()\n");
284
285	mount_info.mntfh = nfs_alloc_fhandle();
286	if (mount_info.cloned == NULL \|\| mount_info.mntfh == NULL)
287	goto out;
288
289	/* create a new volume representation */
290	server = nfs4_create_referral_server(mount_info.cloned, mount_info.mntfh);
291	if (IS_ERR(server)) {
292	mntroot = ERR_CAST(server);
293	goto out;
294	}
295
296	mntroot = nfs_fs_mount_common(&nfs4_fs_type, server, flags, dev_name, &mount_info);
297	out:
298	nfs_free_fhandle(mount_info.mntfh);
299	return mntroot;
300	}
301
302	/*
303	* Create an NFS4 server record on referral traversal
304	*/
305	static struct dentry nfs4_referral_mount(struct file_system_type fs_type,
306	int flags, const char dev_name, void raw_data)
307	{
308	struct nfs_clone_mount *data = raw_data;
309	char *export_path;
310	struct vfsmount *root_mnt;
311	struct dentry *res;
312
313	dprintk("--> nfs4_referral_mount()\n");
314
315	export_path = data->mnt_path;
316	data->mnt_path = "/";
317
318	root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
319	flags, data, data->hostname);
320	data->mnt_path = export_path;
321
322	res = nfs_follow_remote_path(root_mnt, export_path);
323	dprintk("<-- nfs4_referral_mount() = %ld%s\n",
324	IS_ERR(res) ? PTR_ERR(res) : 0,
325	IS_ERR(res) ? " [error]" : "");
326	return res;
327	}
328
329
129d1977 BS	330	int __init init_nfs_v4(void)
	331	{
	332	int err;
	333
	334	err = nfs_idmap_init();
	335	if (err)
	336	goto out;
	337
466bfe7f BS	338	err = nfs4_register_sysctl();
	339	if (err)
	340	goto out1;
	341
fbdefd64 BS	342	err = register_filesystem(&nfs4_fs_type);
	343	if (err < 0)
	344	goto out2;
	345
129d1977	346	return 0;
fbdefd64 BS	347	out2:
fbdefd64 BS	348	nfs4_unregister_sysctl();
466bfe7f BS	349	out1:
466bfe7f BS	350	nfs_idmap_quit();
129d1977 BS	351	out:
	352	return err;
	353	}
	354
bb6e071f	355	void exit_nfs_v4(void)
129d1977	356	{
fbdefd64	357	unregister_filesystem(&nfs4_fs_type);
466bfe7f	358	nfs4_unregister_sysctl();
129d1977 BS	359	nfs_idmap_quit();
129d1977 BS	360	}