aboutsummaryrefslogtreecommitdiff
path: root/fs/nfs/nfs4super.c
blob: 6fb7cb6b3f4b038398e3c8ef1681cc4d274636a5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
/*
 * Copyright (c) 2012 Bryan Schumaker <bjschuma@netapp.com>
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/nfs4_mount.h>
#include <linux/nfs_fs.h>
#include "delegation.h"
#include "internal.h"
#include "nfs4_fs.h"
#include "nfs4idmap.h"
#include "dns_resolve.h"
#include "pnfs.h"
#include "nfs.h"

#define NFSDBG_FACILITY		NFSDBG_VFS

static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc);
static void nfs4_evict_inode(struct inode *inode);
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_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_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_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_BINARY_MOUNTDATA,
};

static const struct super_operations nfs4_sops = {
	.alloc_inode	= nfs_alloc_inode,
	.destroy_inode	= nfs_destroy_inode,
	.write_inode	= nfs4_write_inode,
	.drop_inode	= nfs_drop_inode,
	.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,
	.sops     = &nfs4_sops,
	.xattr    = nfs4_xattr_handlers,
};

static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc)
{
	int ret = nfs_write_inode(inode, wbc);

	if (ret == 0)
		ret = pnfs_layoutcommit_inode(inode,
				wbc->sync_mode == WB_SYNC_ALL);
	return ret;
}

/*
 * Clean out any remaining NFSv4 state that might be left over due
 * to open() calls that passed nfs_atomic_lookup, but failed to call
 * nfs_open().
 */
static void nfs4_evict_inode(struct inode *inode)
{
	truncate_inode_pages_final(&inode->i_data);
	clear_inode(inode);
	/* If we are holding a delegation, return it! */
	nfs_inode_return_delegation_noreclaim(inode);
	/* Note that above delegreturn would trigger pnfs return-on-close */
	pnfs_return_layout(inode);
	pnfs_destroy_layout(NFS_I(inode));
	/* First call standard NFS clear_inode() code */
	nfs_clear_inode(inode);
}

/*
 * 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->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");

	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() = %d%s\n",
		 PTR_ERR_OR_ZERO(res),
		 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 = nfs_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() = %d%s\n",
		PTR_ERR_OR_ZERO(res),
		IS_ERR(res) ? " [error]" : "");
	return res;
}


static int __init init_nfs_v4(void)
{
	int err;

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

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

	err = nfs4_register_sysctl();
	if (err)
		goto out2;

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

static void __exit exit_nfs_v4(void)
{
	/* Not called in the _init(), conditionally loaded */
	nfs4_pnfs_v3_ds_connect_unload();

	unregister_nfs_version(&nfs_v4);
	nfs4_unregister_sysctl();
	nfs_idmap_quit();
	nfs_dns_resolver_destroy();
}

MODULE_LICENSE("GPL");

module_init(init_nfs_v4);
module_exit(exit_nfs_v4);