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1/*
2 * Copyright (c) 2012 Bryan Schumaker <bjschuma@netapp.com>
3 */
4#include <linux/init.h>
5#include <linux/module.h>
6#include <linux/nfs4_mount.h>
7#include <linux/nfs_fs.h>
8#include "delegation.h"
9#include "internal.h"
10#include "nfs4_fs.h"
11#include "nfs4idmap.h"
12#include "dns_resolve.h"
13#include "pnfs.h"
14#include "nfs.h"
15
16#define NFSDBG_FACILITY NFSDBG_VFS
17
18static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc);
19static void nfs4_evict_inode(struct inode *inode);
20static struct dentry *nfs4_remote_mount(struct file_system_type *fs_type,
21 int flags, const char *dev_name, void *raw_data);
22static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
23 int flags, const char *dev_name, void *raw_data);
24static struct dentry *nfs4_remote_referral_mount(struct file_system_type *fs_type,
25 int flags, const char *dev_name, void *raw_data);
26
27static struct file_system_type nfs4_remote_fs_type = {
28 .owner = THIS_MODULE,
29 .name = "nfs4",
30 .mount = nfs4_remote_mount,
31 .kill_sb = nfs_kill_super,
32 .fs_flags = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
33};
34
35static struct file_system_type nfs4_remote_referral_fs_type = {
36 .owner = THIS_MODULE,
37 .name = "nfs4",
38 .mount = nfs4_remote_referral_mount,
39 .kill_sb = nfs_kill_super,
40 .fs_flags = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
41};
42
43struct file_system_type nfs4_referral_fs_type = {
44 .owner = THIS_MODULE,
45 .name = "nfs4",
46 .mount = nfs4_referral_mount,
47 .kill_sb = nfs_kill_super,
48 .fs_flags = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
49};
50
51static const struct super_operations nfs4_sops = {
52 .alloc_inode = nfs_alloc_inode,
53 .destroy_inode = nfs_destroy_inode,
54 .write_inode = nfs4_write_inode,
55 .drop_inode = nfs_drop_inode,
56 .statfs = nfs_statfs,
57 .evict_inode = nfs4_evict_inode,
58 .umount_begin = nfs_umount_begin,
59 .show_options = nfs_show_options,
60 .show_devname = nfs_show_devname,
61 .show_path = nfs_show_path,
62 .show_stats = nfs_show_stats,
63 .remount_fs = nfs_remount,
64};
65
66struct nfs_subversion nfs_v4 = {
67 .owner = THIS_MODULE,
68 .nfs_fs = &nfs4_fs_type,
69 .rpc_vers = &nfs_version4,
70 .rpc_ops = &nfs_v4_clientops,
71 .sops = &nfs4_sops,
72 .xattr = nfs4_xattr_handlers,
73};
74
75static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc)
76{
77 int ret = nfs_write_inode(inode, wbc);
78
79 if (ret == 0)
80 ret = pnfs_layoutcommit_inode(inode,
81 wbc->sync_mode == WB_SYNC_ALL);
82 return ret;
83}
84
85/*
86 * Clean out any remaining NFSv4 state that might be left over due
87 * to open() calls that passed nfs_atomic_lookup, but failed to call
88 * nfs_open().
89 */
90static void nfs4_evict_inode(struct inode *inode)
91{
92 truncate_inode_pages_final(&inode->i_data);
93 clear_inode(inode);
94 /* If we are holding a delegation, return it! */
95 nfs_inode_return_delegation_noreclaim(inode);
96 /* Note that above delegreturn would trigger pnfs return-on-close */
97 pnfs_return_layout(inode);
98 pnfs_destroy_layout(NFS_I(inode));
99 /* First call standard NFS clear_inode() code */
100 nfs_clear_inode(inode);
101}
102
103/*
104 * Get the superblock for the NFS4 root partition
105 */
106static struct dentry *
107nfs4_remote_mount(struct file_system_type *fs_type, int flags,
108 const char *dev_name, void *info)
109{
110 struct nfs_mount_info *mount_info = info;
111 struct nfs_server *server;
112 struct dentry *mntroot = ERR_PTR(-ENOMEM);
113
114 mount_info->set_security = nfs_set_sb_security;
115
116 /* Get a volume representation */
117 server = nfs4_create_server(mount_info, &nfs_v4);
118 if (IS_ERR(server)) {
119 mntroot = ERR_CAST(server);
120 goto out;
121 }
122
123 mntroot = nfs_fs_mount_common(server, flags, dev_name, mount_info, &nfs_v4);
124
125out:
126 return mntroot;
127}
128
129static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
130 int flags, void *data, const char *hostname)
131{
132 struct vfsmount *root_mnt;
133 char *root_devname;
134 size_t len;
135
136 len = strlen(hostname) + 5;
137 root_devname = kmalloc(len, GFP_KERNEL);
138 if (root_devname == NULL)
139 return ERR_PTR(-ENOMEM);
140 /* Does hostname needs to be enclosed in brackets? */
141 if (strchr(hostname, ':'))
142 snprintf(root_devname, len, "[%s]:/", hostname);
143 else
144 snprintf(root_devname, len, "%s:/", hostname);
145 root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
146 kfree(root_devname);
147 return root_mnt;
148}
149
150struct nfs_referral_count {
151 struct list_head list;
152 const struct task_struct *task;
153 unsigned int referral_count;
154};
155
156static LIST_HEAD(nfs_referral_count_list);
157static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
158
159static struct nfs_referral_count *nfs_find_referral_count(void)
160{
161 struct nfs_referral_count *p;
162
163 list_for_each_entry(p, &nfs_referral_count_list, list) {
164 if (p->task == current)
165 return p;
166 }
167 return NULL;
168}
169
170#define NFS_MAX_NESTED_REFERRALS 2
171
172static int nfs_referral_loop_protect(void)
173{
174 struct nfs_referral_count *p, *new;
175 int ret = -ENOMEM;
176
177 new = kmalloc(sizeof(*new), GFP_KERNEL);
178 if (!new)
179 goto out;
180 new->task = current;
181 new->referral_count = 1;
182
183 ret = 0;
184 spin_lock(&nfs_referral_count_list_lock);
185 p = nfs_find_referral_count();
186 if (p != NULL) {
187 if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
188 ret = -ELOOP;
189 else
190 p->referral_count++;
191 } else {
192 list_add(&new->list, &nfs_referral_count_list);
193 new = NULL;
194 }
195 spin_unlock(&nfs_referral_count_list_lock);
196 kfree(new);
197out:
198 return ret;
199}
200
201static void nfs_referral_loop_unprotect(void)
202{
203 struct nfs_referral_count *p;
204
205 spin_lock(&nfs_referral_count_list_lock);
206 p = nfs_find_referral_count();
207 p->referral_count--;
208 if (p->referral_count == 0)
209 list_del(&p->list);
210 else
211 p = NULL;
212 spin_unlock(&nfs_referral_count_list_lock);
213 kfree(p);
214}
215
216static struct dentry *nfs_follow_remote_path(struct vfsmount *root_mnt,
217 const char *export_path)
218{
219 struct dentry *dentry;
220 int err;
221
222 if (IS_ERR(root_mnt))
223 return ERR_CAST(root_mnt);
224
225 err = nfs_referral_loop_protect();
226 if (err) {
227 mntput(root_mnt);
228 return ERR_PTR(err);
229 }
230
231 dentry = mount_subtree(root_mnt, export_path);
232 nfs_referral_loop_unprotect();
233
234 return dentry;
235}
236
237struct dentry *nfs4_try_mount(int flags, const char *dev_name,
238 struct nfs_mount_info *mount_info,
239 struct nfs_subversion *nfs_mod)
240{
241 char *export_path;
242 struct vfsmount *root_mnt;
243 struct dentry *res;
244 struct nfs_parsed_mount_data *data = mount_info->parsed;
245
246 dfprintk(MOUNT, "--> nfs4_try_mount()\n");
247
248 export_path = data->nfs_server.export_path;
249 data->nfs_server.export_path = "/";
250 root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, mount_info,
251 data->nfs_server.hostname);
252 data->nfs_server.export_path = export_path;
253
254 res = nfs_follow_remote_path(root_mnt, export_path);
255
256 dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n",
257 PTR_ERR_OR_ZERO(res),
258 IS_ERR(res) ? " [error]" : "");
259 return res;
260}
261
262static struct dentry *
263nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
264 const char *dev_name, void *raw_data)
265{
266 struct nfs_mount_info mount_info = {
267 .fill_super = nfs_fill_super,
268 .set_security = nfs_clone_sb_security,
269 .cloned = raw_data,
270 };
271 struct nfs_server *server;
272 struct dentry *mntroot = ERR_PTR(-ENOMEM);
273
274 dprintk("--> nfs4_referral_get_sb()\n");
275
276 mount_info.mntfh = nfs_alloc_fhandle();
277 if (mount_info.cloned == NULL || mount_info.mntfh == NULL)
278 goto out;
279
280 /* create a new volume representation */
281 server = nfs4_create_referral_server(mount_info.cloned, mount_info.mntfh);
282 if (IS_ERR(server)) {
283 mntroot = ERR_CAST(server);
284 goto out;
285 }
286
287 mntroot = nfs_fs_mount_common(server, flags, dev_name, &mount_info, &nfs_v4);
288out:
289 nfs_free_fhandle(mount_info.mntfh);
290 return mntroot;
291}
292
293/*
294 * Create an NFS4 server record on referral traversal
295 */
296static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
297 int flags, const char *dev_name, void *raw_data)
298{
299 struct nfs_clone_mount *data = raw_data;
300 char *export_path;
301 struct vfsmount *root_mnt;
302 struct dentry *res;
303
304 dprintk("--> nfs4_referral_mount()\n");
305
306 export_path = data->mnt_path;
307 data->mnt_path = "/";
308
309 root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
310 flags, data, data->hostname);
311 data->mnt_path = export_path;
312
313 res = nfs_follow_remote_path(root_mnt, export_path);
314 dprintk("<-- nfs4_referral_mount() = %d%s\n",
315 PTR_ERR_OR_ZERO(res),
316 IS_ERR(res) ? " [error]" : "");
317 return res;
318}
319
320
321static int __init init_nfs_v4(void)
322{
323 int err;
324
325 err = nfs_dns_resolver_init();
326 if (err)
327 goto out;
328
329 err = nfs_idmap_init();
330 if (err)
331 goto out1;
332
333 err = nfs4_register_sysctl();
334 if (err)
335 goto out2;
336
337 register_nfs_version(&nfs_v4);
338 return 0;
339out2:
340 nfs_idmap_quit();
341out1:
342 nfs_dns_resolver_destroy();
343out:
344 return err;
345}
346
347static void __exit exit_nfs_v4(void)
348{
349 /* Not called in the _init(), conditionally loaded */
350 nfs4_pnfs_v3_ds_connect_unload();
351
352 unregister_nfs_version(&nfs_v4);
353 nfs4_unregister_sysctl();
354 nfs_idmap_quit();
355 nfs_dns_resolver_destroy();
356}
357
358MODULE_LICENSE("GPL");
359
360module_init(init_nfs_v4);
361module_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/mount.h>
8#include <linux/nfs4_mount.h>
9#include <linux/nfs_fs.h>
10#include <linux/nfs_ssc.h>
11#include "delegation.h"
12#include "internal.h"
13#include "nfs4_fs.h"
14#include "nfs4idmap.h"
15#include "dns_resolve.h"
16#include "pnfs.h"
17#include "nfs.h"
18
19#define NFSDBG_FACILITY NFSDBG_VFS
20
21static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc);
22static void nfs4_evict_inode(struct inode *inode);
23
24static const struct super_operations nfs4_sops = {
25 .alloc_inode = nfs_alloc_inode,
26 .free_inode = nfs_free_inode,
27 .write_inode = nfs4_write_inode,
28 .drop_inode = nfs_drop_inode,
29 .statfs = nfs_statfs,
30 .evict_inode = nfs4_evict_inode,
31 .umount_begin = nfs_umount_begin,
32 .show_options = nfs_show_options,
33 .show_devname = nfs_show_devname,
34 .show_path = nfs_show_path,
35 .show_stats = nfs_show_stats,
36};
37
38struct nfs_subversion nfs_v4 = {
39 .owner = THIS_MODULE,
40 .nfs_fs = &nfs4_fs_type,
41 .rpc_vers = &nfs_version4,
42 .rpc_ops = &nfs_v4_clientops,
43 .sops = &nfs4_sops,
44 .xattr = nfs4_xattr_handlers,
45};
46
47static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc)
48{
49 int ret = nfs_write_inode(inode, wbc);
50
51 if (ret == 0)
52 ret = pnfs_layoutcommit_inode(inode,
53 wbc->sync_mode == WB_SYNC_ALL);
54 return ret;
55}
56
57/*
58 * Clean out any remaining NFSv4 state that might be left over due
59 * to open() calls that passed nfs_atomic_lookup, but failed to call
60 * nfs_open().
61 */
62static void nfs4_evict_inode(struct inode *inode)
63{
64 truncate_inode_pages_final(&inode->i_data);
65 clear_inode(inode);
66 /* If we are holding a delegation, return and free it */
67 nfs_inode_evict_delegation(inode);
68 /* Note that above delegreturn would trigger pnfs return-on-close */
69 pnfs_return_layout(inode);
70 pnfs_destroy_layout_final(NFS_I(inode));
71 /* First call standard NFS clear_inode() code */
72 nfs_clear_inode(inode);
73 nfs4_xattr_cache_zap(inode);
74}
75
76struct nfs_referral_count {
77 struct list_head list;
78 const struct task_struct *task;
79 unsigned int referral_count;
80};
81
82static LIST_HEAD(nfs_referral_count_list);
83static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
84
85static struct nfs_referral_count *nfs_find_referral_count(void)
86{
87 struct nfs_referral_count *p;
88
89 list_for_each_entry(p, &nfs_referral_count_list, list) {
90 if (p->task == current)
91 return p;
92 }
93 return NULL;
94}
95
96#define NFS_MAX_NESTED_REFERRALS 2
97
98static int nfs_referral_loop_protect(void)
99{
100 struct nfs_referral_count *p, *new;
101 int ret = -ENOMEM;
102
103 new = kmalloc(sizeof(*new), GFP_KERNEL);
104 if (!new)
105 goto out;
106 new->task = current;
107 new->referral_count = 1;
108
109 ret = 0;
110 spin_lock(&nfs_referral_count_list_lock);
111 p = nfs_find_referral_count();
112 if (p != NULL) {
113 if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
114 ret = -ELOOP;
115 else
116 p->referral_count++;
117 } else {
118 list_add(&new->list, &nfs_referral_count_list);
119 new = NULL;
120 }
121 spin_unlock(&nfs_referral_count_list_lock);
122 kfree(new);
123out:
124 return ret;
125}
126
127static void nfs_referral_loop_unprotect(void)
128{
129 struct nfs_referral_count *p;
130
131 spin_lock(&nfs_referral_count_list_lock);
132 p = nfs_find_referral_count();
133 p->referral_count--;
134 if (p->referral_count == 0)
135 list_del(&p->list);
136 else
137 p = NULL;
138 spin_unlock(&nfs_referral_count_list_lock);
139 kfree(p);
140}
141
142static int do_nfs4_mount(struct nfs_server *server,
143 struct fs_context *fc,
144 const char *hostname,
145 const char *export_path)
146{
147 struct nfs_fs_context *root_ctx;
148 struct fs_context *root_fc;
149 struct vfsmount *root_mnt;
150 struct dentry *dentry;
151 size_t len;
152 int ret;
153
154 struct fs_parameter param = {
155 .key = "source",
156 .type = fs_value_is_string,
157 .dirfd = -1,
158 };
159
160 if (IS_ERR(server))
161 return PTR_ERR(server);
162
163 root_fc = vfs_dup_fs_context(fc);
164 if (IS_ERR(root_fc)) {
165 nfs_free_server(server);
166 return PTR_ERR(root_fc);
167 }
168 kfree(root_fc->source);
169 root_fc->source = NULL;
170
171 root_ctx = nfs_fc2context(root_fc);
172 root_ctx->internal = true;
173 root_ctx->server = server;
174 /* We leave export_path unset as it's not used to find the root. */
175
176 len = strlen(hostname) + 5;
177 param.string = kmalloc(len, GFP_KERNEL);
178 if (param.string == NULL) {
179 put_fs_context(root_fc);
180 return -ENOMEM;
181 }
182
183 /* Does hostname needs to be enclosed in brackets? */
184 if (strchr(hostname, ':'))
185 param.size = snprintf(param.string, len, "[%s]:/", hostname);
186 else
187 param.size = snprintf(param.string, len, "%s:/", hostname);
188 ret = vfs_parse_fs_param(root_fc, ¶m);
189 kfree(param.string);
190 if (ret < 0) {
191 put_fs_context(root_fc);
192 return ret;
193 }
194 root_mnt = fc_mount(root_fc);
195 put_fs_context(root_fc);
196
197 if (IS_ERR(root_mnt))
198 return PTR_ERR(root_mnt);
199
200 ret = nfs_referral_loop_protect();
201 if (ret) {
202 mntput(root_mnt);
203 return ret;
204 }
205
206 dentry = mount_subtree(root_mnt, export_path);
207 nfs_referral_loop_unprotect();
208
209 if (IS_ERR(dentry))
210 return PTR_ERR(dentry);
211
212 fc->root = dentry;
213 return 0;
214}
215
216int nfs4_try_get_tree(struct fs_context *fc)
217{
218 struct nfs_fs_context *ctx = nfs_fc2context(fc);
219 int err;
220
221 dfprintk(MOUNT, "--> nfs4_try_get_tree()\n");
222
223 /* We create a mount for the server's root, walk to the requested
224 * location and then create another mount for that.
225 */
226 err= do_nfs4_mount(nfs4_create_server(fc),
227 fc, ctx->nfs_server.hostname,
228 ctx->nfs_server.export_path);
229 if (err) {
230 nfs_ferrorf(fc, MOUNT, "NFS4: Couldn't follow remote path");
231 dfprintk(MOUNT, "<-- nfs4_try_get_tree() = %d [error]\n", err);
232 } else {
233 dfprintk(MOUNT, "<-- nfs4_try_get_tree() = 0\n");
234 }
235 return err;
236}
237
238/*
239 * Create an NFS4 server record on referral traversal
240 */
241int nfs4_get_referral_tree(struct fs_context *fc)
242{
243 struct nfs_fs_context *ctx = nfs_fc2context(fc);
244 int err;
245
246 dprintk("--> nfs4_referral_mount()\n");
247
248 /* create a new volume representation */
249 err = do_nfs4_mount(nfs4_create_referral_server(fc),
250 fc, ctx->nfs_server.hostname,
251 ctx->nfs_server.export_path);
252 if (err) {
253 nfs_ferrorf(fc, MOUNT, "NFS4: Couldn't follow remote path");
254 dfprintk(MOUNT, "<-- nfs4_get_referral_tree() = %d [error]\n", err);
255 } else {
256 dfprintk(MOUNT, "<-- nfs4_get_referral_tree() = 0\n");
257 }
258 return err;
259}
260
261static int __init init_nfs_v4(void)
262{
263 int err;
264
265 err = nfs_dns_resolver_init();
266 if (err)
267 goto out;
268
269 err = nfs_idmap_init();
270 if (err)
271 goto out1;
272
273#ifdef CONFIG_NFS_V4_2
274 err = nfs4_xattr_cache_init();
275 if (err)
276 goto out2;
277#endif
278
279 err = nfs4_register_sysctl();
280 if (err)
281 goto out2;
282
283#ifdef CONFIG_NFS_V4_2
284 nfs42_ssc_register_ops();
285#endif
286 register_nfs_version(&nfs_v4);
287 return 0;
288out2:
289 nfs_idmap_quit();
290out1:
291 nfs_dns_resolver_destroy();
292out:
293 return err;
294}
295
296static void __exit exit_nfs_v4(void)
297{
298 /* Not called in the _init(), conditionally loaded */
299 nfs4_pnfs_v3_ds_connect_unload();
300
301 unregister_nfs_version(&nfs_v4);
302#ifdef CONFIG_NFS_V4_2
303 nfs4_xattr_cache_exit();
304 nfs42_ssc_unregister_ops();
305#endif
306 nfs4_unregister_sysctl();
307 nfs_idmap_quit();
308 nfs_dns_resolver_destroy();
309}
310
311MODULE_LICENSE("GPL");
312
313module_init(init_nfs_v4);
314module_exit(exit_nfs_v4);