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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 "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);