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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2012 Bryan Schumaker <bjschuma@netapp.com>
4 */
5#include <linux/init.h>
6#include <linux/module.h>
7#include <linux/mount.h>
8#include <linux/nfs4_mount.h>
9#include <linux/nfs_fs.h>
10#include "delegation.h"
11#include "internal.h"
12#include "nfs4_fs.h"
13#include "nfs4idmap.h"
14#include "dns_resolve.h"
15#include "pnfs.h"
16#include "nfs.h"
17
18#define NFSDBG_FACILITY NFSDBG_VFS
19
20static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc);
21static void nfs4_evict_inode(struct inode *inode);
22
23static const struct super_operations nfs4_sops = {
24 .alloc_inode = nfs_alloc_inode,
25 .free_inode = nfs_free_inode,
26 .write_inode = nfs4_write_inode,
27 .drop_inode = nfs_drop_inode,
28 .statfs = nfs_statfs,
29 .evict_inode = nfs4_evict_inode,
30 .umount_begin = nfs_umount_begin,
31 .show_options = nfs_show_options,
32 .show_devname = nfs_show_devname,
33 .show_path = nfs_show_path,
34 .show_stats = nfs_show_stats,
35};
36
37struct nfs_subversion nfs_v4 = {
38 .owner = THIS_MODULE,
39 .nfs_fs = &nfs4_fs_type,
40 .rpc_vers = &nfs_version4,
41 .rpc_ops = &nfs_v4_clientops,
42 .sops = &nfs4_sops,
43 .xattr = nfs4_xattr_handlers,
44};
45
46static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc)
47{
48 int ret = nfs_write_inode(inode, wbc);
49
50 if (ret == 0)
51 ret = pnfs_layoutcommit_inode(inode,
52 wbc->sync_mode == WB_SYNC_ALL);
53 return ret;
54}
55
56/*
57 * Clean out any remaining NFSv4 state that might be left over due
58 * to open() calls that passed nfs_atomic_lookup, but failed to call
59 * nfs_open().
60 */
61static void nfs4_evict_inode(struct inode *inode)
62{
63 truncate_inode_pages_final(&inode->i_data);
64 clear_inode(inode);
65 /* If we are holding a delegation, return and free it */
66 nfs_inode_evict_delegation(inode);
67 /* Note that above delegreturn would trigger pnfs return-on-close */
68 pnfs_return_layout(inode);
69 pnfs_destroy_layout(NFS_I(inode));
70 /* First call standard NFS clear_inode() code */
71 nfs_clear_inode(inode);
72 nfs4_xattr_cache_zap(inode);
73}
74
75struct nfs_referral_count {
76 struct list_head list;
77 const struct task_struct *task;
78 unsigned int referral_count;
79};
80
81static LIST_HEAD(nfs_referral_count_list);
82static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
83
84static struct nfs_referral_count *nfs_find_referral_count(void)
85{
86 struct nfs_referral_count *p;
87
88 list_for_each_entry(p, &nfs_referral_count_list, list) {
89 if (p->task == current)
90 return p;
91 }
92 return NULL;
93}
94
95#define NFS_MAX_NESTED_REFERRALS 2
96
97static int nfs_referral_loop_protect(void)
98{
99 struct nfs_referral_count *p, *new;
100 int ret = -ENOMEM;
101
102 new = kmalloc(sizeof(*new), GFP_KERNEL);
103 if (!new)
104 goto out;
105 new->task = current;
106 new->referral_count = 1;
107
108 ret = 0;
109 spin_lock(&nfs_referral_count_list_lock);
110 p = nfs_find_referral_count();
111 if (p != NULL) {
112 if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
113 ret = -ELOOP;
114 else
115 p->referral_count++;
116 } else {
117 list_add(&new->list, &nfs_referral_count_list);
118 new = NULL;
119 }
120 spin_unlock(&nfs_referral_count_list_lock);
121 kfree(new);
122out:
123 return ret;
124}
125
126static void nfs_referral_loop_unprotect(void)
127{
128 struct nfs_referral_count *p;
129
130 spin_lock(&nfs_referral_count_list_lock);
131 p = nfs_find_referral_count();
132 p->referral_count--;
133 if (p->referral_count == 0)
134 list_del(&p->list);
135 else
136 p = NULL;
137 spin_unlock(&nfs_referral_count_list_lock);
138 kfree(p);
139}
140
141static int do_nfs4_mount(struct nfs_server *server,
142 struct fs_context *fc,
143 const char *hostname,
144 const char *export_path)
145{
146 struct nfs_fs_context *root_ctx;
147 struct fs_context *root_fc;
148 struct vfsmount *root_mnt;
149 struct dentry *dentry;
150 size_t len;
151 int ret;
152
153 struct fs_parameter param = {
154 .key = "source",
155 .type = fs_value_is_string,
156 .dirfd = -1,
157 };
158
159 if (IS_ERR(server))
160 return PTR_ERR(server);
161
162 root_fc = vfs_dup_fs_context(fc);
163 if (IS_ERR(root_fc)) {
164 nfs_free_server(server);
165 return PTR_ERR(root_fc);
166 }
167 kfree(root_fc->source);
168 root_fc->source = NULL;
169
170 root_ctx = nfs_fc2context(root_fc);
171 root_ctx->internal = true;
172 root_ctx->server = server;
173 /* We leave export_path unset as it's not used to find the root. */
174
175 len = strlen(hostname) + 5;
176 param.string = kmalloc(len, GFP_KERNEL);
177 if (param.string == NULL) {
178 put_fs_context(root_fc);
179 return -ENOMEM;
180 }
181
182 /* Does hostname needs to be enclosed in brackets? */
183 if (strchr(hostname, ':'))
184 param.size = snprintf(param.string, len, "[%s]:/", hostname);
185 else
186 param.size = snprintf(param.string, len, "%s:/", hostname);
187 ret = vfs_parse_fs_param(root_fc, ¶m);
188 kfree(param.string);
189 if (ret < 0) {
190 put_fs_context(root_fc);
191 return ret;
192 }
193 root_mnt = fc_mount(root_fc);
194 put_fs_context(root_fc);
195
196 if (IS_ERR(root_mnt))
197 return PTR_ERR(root_mnt);
198
199 ret = nfs_referral_loop_protect();
200 if (ret) {
201 mntput(root_mnt);
202 return ret;
203 }
204
205 dentry = mount_subtree(root_mnt, export_path);
206 nfs_referral_loop_unprotect();
207
208 if (IS_ERR(dentry))
209 return PTR_ERR(dentry);
210
211 fc->root = dentry;
212 return 0;
213}
214
215int nfs4_try_get_tree(struct fs_context *fc)
216{
217 struct nfs_fs_context *ctx = nfs_fc2context(fc);
218 int err;
219
220 dfprintk(MOUNT, "--> nfs4_try_get_tree()\n");
221
222 /* We create a mount for the server's root, walk to the requested
223 * location and then create another mount for that.
224 */
225 err= do_nfs4_mount(nfs4_create_server(fc),
226 fc, ctx->nfs_server.hostname,
227 ctx->nfs_server.export_path);
228 if (err) {
229 nfs_errorf(fc, "NFS4: Couldn't follow remote path");
230 dfprintk(MOUNT, "<-- nfs4_try_get_tree() = %d [error]\n", err);
231 } else {
232 dfprintk(MOUNT, "<-- nfs4_try_get_tree() = 0\n");
233 }
234 return err;
235}
236
237/*
238 * Create an NFS4 server record on referral traversal
239 */
240int nfs4_get_referral_tree(struct fs_context *fc)
241{
242 struct nfs_fs_context *ctx = nfs_fc2context(fc);
243 int err;
244
245 dprintk("--> nfs4_referral_mount()\n");
246
247 /* create a new volume representation */
248 err = do_nfs4_mount(nfs4_create_referral_server(fc),
249 fc, ctx->nfs_server.hostname,
250 ctx->nfs_server.export_path);
251 if (err) {
252 nfs_errorf(fc, "NFS4: Couldn't follow remote path");
253 dfprintk(MOUNT, "<-- nfs4_get_referral_tree() = %d [error]\n", err);
254 } else {
255 dfprintk(MOUNT, "<-- nfs4_get_referral_tree() = 0\n");
256 }
257 return err;
258}
259
260static int __init init_nfs_v4(void)
261{
262 int err;
263
264 err = nfs_dns_resolver_init();
265 if (err)
266 goto out;
267
268 err = nfs_idmap_init();
269 if (err)
270 goto out1;
271
272#ifdef CONFIG_NFS_V4_2
273 err = nfs4_xattr_cache_init();
274 if (err)
275 goto out2;
276#endif
277
278 err = nfs4_register_sysctl();
279 if (err)
280 goto out2;
281
282 register_nfs_version(&nfs_v4);
283 return 0;
284out2:
285 nfs_idmap_quit();
286out1:
287 nfs_dns_resolver_destroy();
288out:
289 return err;
290}
291
292static void __exit exit_nfs_v4(void)
293{
294 /* Not called in the _init(), conditionally loaded */
295 nfs4_pnfs_v3_ds_connect_unload();
296
297 unregister_nfs_version(&nfs_v4);
298#ifdef CONFIG_NFS_V4_2
299 nfs4_xattr_cache_exit();
300#endif
301 nfs4_unregister_sysctl();
302 nfs_idmap_quit();
303 nfs_dns_resolver_destroy();
304}
305
306MODULE_LICENSE("GPL");
307
308module_init(init_nfs_v4);
309module_exit(exit_nfs_v4);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2012 Bryan Schumaker <bjschuma@netapp.com>
4 */
5#include <linux/init.h>
6#include <linux/module.h>
7#include <linux/nfs4_mount.h>
8#include <linux/nfs_fs.h>
9#include "delegation.h"
10#include "internal.h"
11#include "nfs4_fs.h"
12#include "nfs4idmap.h"
13#include "dns_resolve.h"
14#include "pnfs.h"
15#include "nfs.h"
16
17#define NFSDBG_FACILITY NFSDBG_VFS
18
19static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc);
20static void nfs4_evict_inode(struct inode *inode);
21static struct dentry *nfs4_remote_mount(struct file_system_type *fs_type,
22 int flags, const char *dev_name, void *raw_data);
23static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
24 int flags, const char *dev_name, void *raw_data);
25static struct dentry *nfs4_remote_referral_mount(struct file_system_type *fs_type,
26 int flags, const char *dev_name, void *raw_data);
27
28static struct file_system_type nfs4_remote_fs_type = {
29 .owner = THIS_MODULE,
30 .name = "nfs4",
31 .mount = nfs4_remote_mount,
32 .kill_sb = nfs_kill_super,
33 .fs_flags = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
34};
35
36static struct file_system_type nfs4_remote_referral_fs_type = {
37 .owner = THIS_MODULE,
38 .name = "nfs4",
39 .mount = nfs4_remote_referral_mount,
40 .kill_sb = nfs_kill_super,
41 .fs_flags = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
42};
43
44struct file_system_type nfs4_referral_fs_type = {
45 .owner = THIS_MODULE,
46 .name = "nfs4",
47 .mount = nfs4_referral_mount,
48 .kill_sb = nfs_kill_super,
49 .fs_flags = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
50};
51
52static const struct super_operations nfs4_sops = {
53 .alloc_inode = nfs_alloc_inode,
54 .free_inode = nfs_free_inode,
55 .write_inode = nfs4_write_inode,
56 .drop_inode = nfs_drop_inode,
57 .statfs = nfs_statfs,
58 .evict_inode = nfs4_evict_inode,
59 .umount_begin = nfs_umount_begin,
60 .show_options = nfs_show_options,
61 .show_devname = nfs_show_devname,
62 .show_path = nfs_show_path,
63 .show_stats = nfs_show_stats,
64 .remount_fs = nfs_remount,
65};
66
67struct nfs_subversion nfs_v4 = {
68 .owner = THIS_MODULE,
69 .nfs_fs = &nfs4_fs_type,
70 .rpc_vers = &nfs_version4,
71 .rpc_ops = &nfs_v4_clientops,
72 .sops = &nfs4_sops,
73 .xattr = nfs4_xattr_handlers,
74};
75
76static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc)
77{
78 int ret = nfs_write_inode(inode, wbc);
79
80 if (ret == 0)
81 ret = pnfs_layoutcommit_inode(inode,
82 wbc->sync_mode == WB_SYNC_ALL);
83 return ret;
84}
85
86/*
87 * Clean out any remaining NFSv4 state that might be left over due
88 * to open() calls that passed nfs_atomic_lookup, but failed to call
89 * nfs_open().
90 */
91static void nfs4_evict_inode(struct inode *inode)
92{
93 truncate_inode_pages_final(&inode->i_data);
94 clear_inode(inode);
95 /* If we are holding a delegation, return it! */
96 nfs_inode_return_delegation_noreclaim(inode);
97 /* Note that above delegreturn would trigger pnfs return-on-close */
98 pnfs_return_layout(inode);
99 pnfs_destroy_layout(NFS_I(inode));
100 /* First call standard NFS clear_inode() code */
101 nfs_clear_inode(inode);
102}
103
104/*
105 * Get the superblock for the NFS4 root partition
106 */
107static struct dentry *
108nfs4_remote_mount(struct file_system_type *fs_type, int flags,
109 const char *dev_name, void *info)
110{
111 struct nfs_mount_info *mount_info = info;
112 struct nfs_server *server;
113 struct dentry *mntroot = ERR_PTR(-ENOMEM);
114
115 mount_info->set_security = nfs_set_sb_security;
116
117 /* Get a volume representation */
118 server = nfs4_create_server(mount_info, &nfs_v4);
119 if (IS_ERR(server)) {
120 mntroot = ERR_CAST(server);
121 goto out;
122 }
123
124 mntroot = nfs_fs_mount_common(server, flags, dev_name, mount_info, &nfs_v4);
125
126out:
127 return mntroot;
128}
129
130static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
131 int flags, void *data, const char *hostname)
132{
133 struct vfsmount *root_mnt;
134 char *root_devname;
135 size_t len;
136
137 len = strlen(hostname) + 5;
138 root_devname = kmalloc(len, GFP_KERNEL);
139 if (root_devname == NULL)
140 return ERR_PTR(-ENOMEM);
141 /* Does hostname needs to be enclosed in brackets? */
142 if (strchr(hostname, ':'))
143 snprintf(root_devname, len, "[%s]:/", hostname);
144 else
145 snprintf(root_devname, len, "%s:/", hostname);
146 root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
147 kfree(root_devname);
148 return root_mnt;
149}
150
151struct nfs_referral_count {
152 struct list_head list;
153 const struct task_struct *task;
154 unsigned int referral_count;
155};
156
157static LIST_HEAD(nfs_referral_count_list);
158static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
159
160static struct nfs_referral_count *nfs_find_referral_count(void)
161{
162 struct nfs_referral_count *p;
163
164 list_for_each_entry(p, &nfs_referral_count_list, list) {
165 if (p->task == current)
166 return p;
167 }
168 return NULL;
169}
170
171#define NFS_MAX_NESTED_REFERRALS 2
172
173static int nfs_referral_loop_protect(void)
174{
175 struct nfs_referral_count *p, *new;
176 int ret = -ENOMEM;
177
178 new = kmalloc(sizeof(*new), GFP_KERNEL);
179 if (!new)
180 goto out;
181 new->task = current;
182 new->referral_count = 1;
183
184 ret = 0;
185 spin_lock(&nfs_referral_count_list_lock);
186 p = nfs_find_referral_count();
187 if (p != NULL) {
188 if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
189 ret = -ELOOP;
190 else
191 p->referral_count++;
192 } else {
193 list_add(&new->list, &nfs_referral_count_list);
194 new = NULL;
195 }
196 spin_unlock(&nfs_referral_count_list_lock);
197 kfree(new);
198out:
199 return ret;
200}
201
202static void nfs_referral_loop_unprotect(void)
203{
204 struct nfs_referral_count *p;
205
206 spin_lock(&nfs_referral_count_list_lock);
207 p = nfs_find_referral_count();
208 p->referral_count--;
209 if (p->referral_count == 0)
210 list_del(&p->list);
211 else
212 p = NULL;
213 spin_unlock(&nfs_referral_count_list_lock);
214 kfree(p);
215}
216
217static struct dentry *nfs_follow_remote_path(struct vfsmount *root_mnt,
218 const char *export_path)
219{
220 struct dentry *dentry;
221 int err;
222
223 if (IS_ERR(root_mnt))
224 return ERR_CAST(root_mnt);
225
226 err = nfs_referral_loop_protect();
227 if (err) {
228 mntput(root_mnt);
229 return ERR_PTR(err);
230 }
231
232 dentry = mount_subtree(root_mnt, export_path);
233 nfs_referral_loop_unprotect();
234
235 return dentry;
236}
237
238struct dentry *nfs4_try_mount(int flags, const char *dev_name,
239 struct nfs_mount_info *mount_info,
240 struct nfs_subversion *nfs_mod)
241{
242 char *export_path;
243 struct vfsmount *root_mnt;
244 struct dentry *res;
245 struct nfs_parsed_mount_data *data = mount_info->parsed;
246
247 dfprintk(MOUNT, "--> nfs4_try_mount()\n");
248
249 export_path = data->nfs_server.export_path;
250 data->nfs_server.export_path = "/";
251 root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, mount_info,
252 data->nfs_server.hostname);
253 data->nfs_server.export_path = export_path;
254
255 res = nfs_follow_remote_path(root_mnt, export_path);
256
257 dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n",
258 PTR_ERR_OR_ZERO(res),
259 IS_ERR(res) ? " [error]" : "");
260 return res;
261}
262
263static struct dentry *
264nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
265 const char *dev_name, void *raw_data)
266{
267 struct nfs_mount_info mount_info = {
268 .fill_super = nfs_fill_super,
269 .set_security = nfs_clone_sb_security,
270 .cloned = raw_data,
271 };
272 struct nfs_server *server;
273 struct dentry *mntroot = ERR_PTR(-ENOMEM);
274
275 dprintk("--> nfs4_referral_get_sb()\n");
276
277 mount_info.mntfh = nfs_alloc_fhandle();
278 if (mount_info.cloned == NULL || mount_info.mntfh == NULL)
279 goto out;
280
281 /* create a new volume representation */
282 server = nfs4_create_referral_server(mount_info.cloned, mount_info.mntfh);
283 if (IS_ERR(server)) {
284 mntroot = ERR_CAST(server);
285 goto out;
286 }
287
288 mntroot = nfs_fs_mount_common(server, flags, dev_name, &mount_info, &nfs_v4);
289out:
290 nfs_free_fhandle(mount_info.mntfh);
291 return mntroot;
292}
293
294/*
295 * Create an NFS4 server record on referral traversal
296 */
297static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
298 int flags, const char *dev_name, void *raw_data)
299{
300 struct nfs_clone_mount *data = raw_data;
301 char *export_path;
302 struct vfsmount *root_mnt;
303 struct dentry *res;
304
305 dprintk("--> nfs4_referral_mount()\n");
306
307 export_path = data->mnt_path;
308 data->mnt_path = "/";
309
310 root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
311 flags, data, data->hostname);
312 data->mnt_path = export_path;
313
314 res = nfs_follow_remote_path(root_mnt, export_path);
315 dprintk("<-- nfs4_referral_mount() = %d%s\n",
316 PTR_ERR_OR_ZERO(res),
317 IS_ERR(res) ? " [error]" : "");
318 return res;
319}
320
321
322static int __init init_nfs_v4(void)
323{
324 int err;
325
326 err = nfs_dns_resolver_init();
327 if (err)
328 goto out;
329
330 err = nfs_idmap_init();
331 if (err)
332 goto out1;
333
334 err = nfs4_register_sysctl();
335 if (err)
336 goto out2;
337
338 register_nfs_version(&nfs_v4);
339 return 0;
340out2:
341 nfs_idmap_quit();
342out1:
343 nfs_dns_resolver_destroy();
344out:
345 return err;
346}
347
348static void __exit exit_nfs_v4(void)
349{
350 /* Not called in the _init(), conditionally loaded */
351 nfs4_pnfs_v3_ds_connect_unload();
352
353 unregister_nfs_version(&nfs_v4);
354 nfs4_unregister_sysctl();
355 nfs_idmap_quit();
356 nfs_dns_resolver_destroy();
357}
358
359MODULE_LICENSE("GPL");
360
361module_init(init_nfs_v4);
362module_exit(exit_nfs_v4);