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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/nfs/unlink.c
4 *
5 * nfs sillydelete handling
6 *
7 */
8
9#include <linux/slab.h>
10#include <linux/string.h>
11#include <linux/dcache.h>
12#include <linux/sunrpc/sched.h>
13#include <linux/sunrpc/clnt.h>
14#include <linux/nfs_fs.h>
15#include <linux/sched.h>
16#include <linux/wait.h>
17#include <linux/namei.h>
18#include <linux/fsnotify.h>
19
20#include "internal.h"
21#include "nfs4_fs.h"
22#include "iostat.h"
23#include "delegation.h"
24
25#include "nfstrace.h"
26
27/**
28 * nfs_free_unlinkdata - release data from a sillydelete operation.
29 * @data: pointer to unlink structure.
30 */
31static void
32nfs_free_unlinkdata(struct nfs_unlinkdata *data)
33{
34 put_cred(data->cred);
35 kfree(data->args.name.name);
36 kfree(data);
37}
38
39/**
40 * nfs_async_unlink_done - Sillydelete post-processing
41 * @task: rpc_task of the sillydelete
42 * @calldata: pointer to nfs_unlinkdata
43 *
44 * Do the directory attribute update.
45 */
46static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
47{
48 struct nfs_unlinkdata *data = calldata;
49 struct inode *dir = d_inode(data->dentry->d_parent);
50
51 trace_nfs_sillyrename_unlink(data, task->tk_status);
52 if (!NFS_PROTO(dir)->unlink_done(task, dir))
53 rpc_restart_call_prepare(task);
54}
55
56/**
57 * nfs_async_unlink_release - Release the sillydelete data.
58 * @calldata: struct nfs_unlinkdata to release
59 *
60 * We need to call nfs_put_unlinkdata as a 'tk_release' task since the
61 * rpc_task would be freed too.
62 */
63static void nfs_async_unlink_release(void *calldata)
64{
65 struct nfs_unlinkdata *data = calldata;
66 struct dentry *dentry = data->dentry;
67 struct super_block *sb = dentry->d_sb;
68
69 up_read_non_owner(&NFS_I(d_inode(dentry->d_parent))->rmdir_sem);
70 d_lookup_done(dentry);
71 nfs_free_unlinkdata(data);
72 dput(dentry);
73 nfs_sb_deactive(sb);
74}
75
76static void nfs_unlink_prepare(struct rpc_task *task, void *calldata)
77{
78 struct nfs_unlinkdata *data = calldata;
79 struct inode *dir = d_inode(data->dentry->d_parent);
80 NFS_PROTO(dir)->unlink_rpc_prepare(task, data);
81}
82
83static const struct rpc_call_ops nfs_unlink_ops = {
84 .rpc_call_done = nfs_async_unlink_done,
85 .rpc_release = nfs_async_unlink_release,
86 .rpc_call_prepare = nfs_unlink_prepare,
87};
88
89static void nfs_do_call_unlink(struct inode *inode, struct nfs_unlinkdata *data)
90{
91 struct rpc_message msg = {
92 .rpc_argp = &data->args,
93 .rpc_resp = &data->res,
94 .rpc_cred = data->cred,
95 };
96 struct rpc_task_setup task_setup_data = {
97 .rpc_message = &msg,
98 .callback_ops = &nfs_unlink_ops,
99 .callback_data = data,
100 .workqueue = nfsiod_workqueue,
101 .flags = RPC_TASK_ASYNC | RPC_TASK_CRED_NOREF,
102 };
103 struct rpc_task *task;
104 struct inode *dir = d_inode(data->dentry->d_parent);
105 nfs_sb_active(dir->i_sb);
106 data->args.fh = NFS_FH(dir);
107 nfs_fattr_init(data->res.dir_attr);
108
109 NFS_PROTO(dir)->unlink_setup(&msg, data->dentry, inode);
110
111 task_setup_data.rpc_client = NFS_CLIENT(dir);
112 task = rpc_run_task(&task_setup_data);
113 if (!IS_ERR(task))
114 rpc_put_task_async(task);
115}
116
117static int nfs_call_unlink(struct dentry *dentry, struct inode *inode, struct nfs_unlinkdata *data)
118{
119 struct inode *dir = d_inode(dentry->d_parent);
120 struct dentry *alias;
121
122 down_read_non_owner(&NFS_I(dir)->rmdir_sem);
123 alias = d_alloc_parallel(dentry->d_parent, &data->args.name, &data->wq);
124 if (IS_ERR(alias)) {
125 up_read_non_owner(&NFS_I(dir)->rmdir_sem);
126 return 0;
127 }
128 if (!d_in_lookup(alias)) {
129 int ret;
130 void *devname_garbage = NULL;
131
132 /*
133 * Hey, we raced with lookup... See if we need to transfer
134 * the sillyrename information to the aliased dentry.
135 */
136 spin_lock(&alias->d_lock);
137 if (d_really_is_positive(alias) &&
138 !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
139 devname_garbage = alias->d_fsdata;
140 alias->d_fsdata = data;
141 alias->d_flags |= DCACHE_NFSFS_RENAMED;
142 ret = 1;
143 } else
144 ret = 0;
145 spin_unlock(&alias->d_lock);
146 dput(alias);
147 up_read_non_owner(&NFS_I(dir)->rmdir_sem);
148 /*
149 * If we'd displaced old cached devname, free it. At that
150 * point dentry is definitely not a root, so we won't need
151 * that anymore.
152 */
153 kfree(devname_garbage);
154 return ret;
155 }
156 data->dentry = alias;
157 nfs_do_call_unlink(inode, data);
158 return 1;
159}
160
161/**
162 * nfs_async_unlink - asynchronous unlinking of a file
163 * @dentry: parent directory of dentry
164 * @name: name of dentry to unlink
165 */
166static int
167nfs_async_unlink(struct dentry *dentry, const struct qstr *name)
168{
169 struct nfs_unlinkdata *data;
170 int status = -ENOMEM;
171 void *devname_garbage = NULL;
172
173 data = kzalloc(sizeof(*data), GFP_KERNEL);
174 if (data == NULL)
175 goto out;
176 data->args.name.name = kstrdup(name->name, GFP_KERNEL);
177 if (!data->args.name.name)
178 goto out_free;
179 data->args.name.len = name->len;
180
181 data->cred = get_current_cred();
182 data->res.dir_attr = &data->dir_attr;
183 init_waitqueue_head(&data->wq);
184
185 status = -EBUSY;
186 spin_lock(&dentry->d_lock);
187 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
188 goto out_unlock;
189 dentry->d_flags |= DCACHE_NFSFS_RENAMED;
190 devname_garbage = dentry->d_fsdata;
191 dentry->d_fsdata = data;
192 spin_unlock(&dentry->d_lock);
193 /*
194 * If we'd displaced old cached devname, free it. At that
195 * point dentry is definitely not a root, so we won't need
196 * that anymore.
197 */
198 kfree(devname_garbage);
199 return 0;
200out_unlock:
201 spin_unlock(&dentry->d_lock);
202 put_cred(data->cred);
203 kfree(data->args.name.name);
204out_free:
205 kfree(data);
206out:
207 return status;
208}
209
210/**
211 * nfs_complete_unlink - Initialize completion of the sillydelete
212 * @dentry: dentry to delete
213 * @inode: inode
214 *
215 * Since we're most likely to be called by dentry_iput(), we
216 * only use the dentry to find the sillydelete. We then copy the name
217 * into the qstr.
218 */
219void
220nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
221{
222 struct nfs_unlinkdata *data;
223
224 spin_lock(&dentry->d_lock);
225 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
226 data = dentry->d_fsdata;
227 dentry->d_fsdata = NULL;
228 spin_unlock(&dentry->d_lock);
229
230 if (NFS_STALE(inode) || !nfs_call_unlink(dentry, inode, data))
231 nfs_free_unlinkdata(data);
232}
233
234/* Cancel a queued async unlink. Called when a sillyrename run fails. */
235static void
236nfs_cancel_async_unlink(struct dentry *dentry)
237{
238 spin_lock(&dentry->d_lock);
239 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
240 struct nfs_unlinkdata *data = dentry->d_fsdata;
241
242 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
243 dentry->d_fsdata = NULL;
244 spin_unlock(&dentry->d_lock);
245 nfs_free_unlinkdata(data);
246 return;
247 }
248 spin_unlock(&dentry->d_lock);
249}
250
251/**
252 * nfs_async_rename_done - Sillyrename post-processing
253 * @task: rpc_task of the sillyrename
254 * @calldata: nfs_renamedata for the sillyrename
255 *
256 * Do the directory attribute updates and the d_move
257 */
258static void nfs_async_rename_done(struct rpc_task *task, void *calldata)
259{
260 struct nfs_renamedata *data = calldata;
261 struct inode *old_dir = data->old_dir;
262 struct inode *new_dir = data->new_dir;
263 struct dentry *old_dentry = data->old_dentry;
264
265 trace_nfs_sillyrename_rename(old_dir, old_dentry,
266 new_dir, data->new_dentry, task->tk_status);
267 if (!NFS_PROTO(old_dir)->rename_done(task, old_dir, new_dir)) {
268 rpc_restart_call_prepare(task);
269 return;
270 }
271
272 if (data->complete)
273 data->complete(task, data);
274}
275
276/**
277 * nfs_async_rename_release - Release the sillyrename data.
278 * @calldata: the struct nfs_renamedata to be released
279 */
280static void nfs_async_rename_release(void *calldata)
281{
282 struct nfs_renamedata *data = calldata;
283 struct super_block *sb = data->old_dir->i_sb;
284
285 if (d_really_is_positive(data->old_dentry))
286 nfs_mark_for_revalidate(d_inode(data->old_dentry));
287
288 /* The result of the rename is unknown. Play it safe by
289 * forcing a new lookup */
290 if (data->cancelled) {
291 spin_lock(&data->old_dir->i_lock);
292 nfs_force_lookup_revalidate(data->old_dir);
293 spin_unlock(&data->old_dir->i_lock);
294 if (data->new_dir != data->old_dir) {
295 spin_lock(&data->new_dir->i_lock);
296 nfs_force_lookup_revalidate(data->new_dir);
297 spin_unlock(&data->new_dir->i_lock);
298 }
299 }
300
301 dput(data->old_dentry);
302 dput(data->new_dentry);
303 iput(data->old_dir);
304 iput(data->new_dir);
305 nfs_sb_deactive(sb);
306 put_cred(data->cred);
307 kfree(data);
308}
309
310static void nfs_rename_prepare(struct rpc_task *task, void *calldata)
311{
312 struct nfs_renamedata *data = calldata;
313 NFS_PROTO(data->old_dir)->rename_rpc_prepare(task, data);
314}
315
316static const struct rpc_call_ops nfs_rename_ops = {
317 .rpc_call_done = nfs_async_rename_done,
318 .rpc_release = nfs_async_rename_release,
319 .rpc_call_prepare = nfs_rename_prepare,
320};
321
322/**
323 * nfs_async_rename - perform an asynchronous rename operation
324 * @old_dir: directory that currently holds the dentry to be renamed
325 * @new_dir: target directory for the rename
326 * @old_dentry: original dentry to be renamed
327 * @new_dentry: dentry to which the old_dentry should be renamed
328 * @complete: Function to run on successful completion
329 *
330 * It's expected that valid references to the dentries and inodes are held
331 */
332struct rpc_task *
333nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
334 struct dentry *old_dentry, struct dentry *new_dentry,
335 void (*complete)(struct rpc_task *, struct nfs_renamedata *))
336{
337 struct nfs_renamedata *data;
338 struct rpc_message msg = { };
339 struct rpc_task_setup task_setup_data = {
340 .rpc_message = &msg,
341 .callback_ops = &nfs_rename_ops,
342 .workqueue = nfsiod_workqueue,
343 .rpc_client = NFS_CLIENT(old_dir),
344 .flags = RPC_TASK_ASYNC | RPC_TASK_CRED_NOREF,
345 };
346
347 data = kzalloc(sizeof(*data), GFP_KERNEL);
348 if (data == NULL)
349 return ERR_PTR(-ENOMEM);
350 task_setup_data.callback_data = data;
351
352 data->cred = get_current_cred();
353
354 msg.rpc_argp = &data->args;
355 msg.rpc_resp = &data->res;
356 msg.rpc_cred = data->cred;
357
358 /* set up nfs_renamedata */
359 data->old_dir = old_dir;
360 ihold(old_dir);
361 data->new_dir = new_dir;
362 ihold(new_dir);
363 data->old_dentry = dget(old_dentry);
364 data->new_dentry = dget(new_dentry);
365 nfs_fattr_init(&data->old_fattr);
366 nfs_fattr_init(&data->new_fattr);
367 data->complete = complete;
368
369 /* set up nfs_renameargs */
370 data->args.old_dir = NFS_FH(old_dir);
371 data->args.old_name = &old_dentry->d_name;
372 data->args.new_dir = NFS_FH(new_dir);
373 data->args.new_name = &new_dentry->d_name;
374
375 /* set up nfs_renameres */
376 data->res.old_fattr = &data->old_fattr;
377 data->res.new_fattr = &data->new_fattr;
378
379 nfs_sb_active(old_dir->i_sb);
380
381 NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dentry, new_dentry);
382
383 return rpc_run_task(&task_setup_data);
384}
385
386/*
387 * Perform tasks needed when a sillyrename is done such as cancelling the
388 * queued async unlink if it failed.
389 */
390static void
391nfs_complete_sillyrename(struct rpc_task *task, struct nfs_renamedata *data)
392{
393 struct dentry *dentry = data->old_dentry;
394
395 if (task->tk_status != 0) {
396 nfs_cancel_async_unlink(dentry);
397 return;
398 }
399}
400
401#define SILLYNAME_PREFIX ".nfs"
402#define SILLYNAME_PREFIX_LEN ((unsigned)sizeof(SILLYNAME_PREFIX) - 1)
403#define SILLYNAME_FILEID_LEN ((unsigned)sizeof(u64) << 1)
404#define SILLYNAME_COUNTER_LEN ((unsigned)sizeof(unsigned int) << 1)
405#define SILLYNAME_LEN (SILLYNAME_PREFIX_LEN + \
406 SILLYNAME_FILEID_LEN + \
407 SILLYNAME_COUNTER_LEN)
408
409/**
410 * nfs_sillyrename - Perform a silly-rename of a dentry
411 * @dir: inode of directory that contains dentry
412 * @dentry: dentry to be sillyrenamed
413 *
414 * NFSv2/3 is stateless and the server doesn't know when the client is
415 * holding a file open. To prevent application problems when a file is
416 * unlinked while it's still open, the client performs a "silly-rename".
417 * That is, it renames the file to a hidden file in the same directory,
418 * and only performs the unlink once the last reference to it is put.
419 *
420 * The final cleanup is done during dentry_iput.
421 *
422 * (Note: NFSv4 is stateful, and has opens, so in theory an NFSv4 server
423 * could take responsibility for keeping open files referenced. The server
424 * would also need to ensure that opened-but-deleted files were kept over
425 * reboots. However, we may not assume a server does so. (RFC 5661
426 * does provide an OPEN4_RESULT_PRESERVE_UNLINKED flag that a server can
427 * use to advertise that it does this; some day we may take advantage of
428 * it.))
429 */
430int
431nfs_sillyrename(struct inode *dir, struct dentry *dentry)
432{
433 static unsigned int sillycounter;
434 unsigned char silly[SILLYNAME_LEN + 1];
435 unsigned long long fileid;
436 struct dentry *sdentry;
437 struct inode *inode = d_inode(dentry);
438 struct rpc_task *task;
439 int error = -EBUSY;
440
441 dfprintk(VFS, "NFS: silly-rename(%pd2, ct=%d)\n",
442 dentry, d_count(dentry));
443 nfs_inc_stats(dir, NFSIOS_SILLYRENAME);
444
445 /*
446 * We don't allow a dentry to be silly-renamed twice.
447 */
448 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
449 goto out;
450
451 fileid = NFS_FILEID(d_inode(dentry));
452
453 sdentry = NULL;
454 do {
455 int slen;
456 dput(sdentry);
457 sillycounter++;
458 slen = scnprintf(silly, sizeof(silly),
459 SILLYNAME_PREFIX "%0*llx%0*x",
460 SILLYNAME_FILEID_LEN, fileid,
461 SILLYNAME_COUNTER_LEN, sillycounter);
462
463 dfprintk(VFS, "NFS: trying to rename %pd to %s\n",
464 dentry, silly);
465
466 sdentry = lookup_one_len(silly, dentry->d_parent, slen);
467 /*
468 * N.B. Better to return EBUSY here ... it could be
469 * dangerous to delete the file while it's in use.
470 */
471 if (IS_ERR(sdentry))
472 goto out;
473 } while (d_inode(sdentry) != NULL); /* need negative lookup */
474
475 ihold(inode);
476
477 /* queue unlink first. Can't do this from rpc_release as it
478 * has to allocate memory
479 */
480 error = nfs_async_unlink(dentry, &sdentry->d_name);
481 if (error)
482 goto out_dput;
483
484 /* run the rename task, undo unlink if it fails */
485 task = nfs_async_rename(dir, dir, dentry, sdentry,
486 nfs_complete_sillyrename);
487 if (IS_ERR(task)) {
488 error = -EBUSY;
489 nfs_cancel_async_unlink(dentry);
490 goto out_dput;
491 }
492
493 /* wait for the RPC task to complete, unless a SIGKILL intervenes */
494 error = rpc_wait_for_completion_task(task);
495 if (error == 0)
496 error = task->tk_status;
497 switch (error) {
498 case 0:
499 /* The rename succeeded */
500 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
501 spin_lock(&inode->i_lock);
502 NFS_I(inode)->attr_gencount = nfs_inc_attr_generation_counter();
503 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_CHANGE
504 | NFS_INO_INVALID_CTIME
505 | NFS_INO_REVAL_FORCED;
506 spin_unlock(&inode->i_lock);
507 d_move(dentry, sdentry);
508 break;
509 case -ERESTARTSYS:
510 /* The result of the rename is unknown. Play it safe by
511 * forcing a new lookup */
512 d_drop(dentry);
513 d_drop(sdentry);
514 }
515 rpc_put_task(task);
516out_dput:
517 iput(inode);
518 dput(sdentry);
519out:
520 return error;
521}
1/*
2 * linux/fs/nfs/unlink.c
3 *
4 * nfs sillydelete handling
5 *
6 */
7
8#include <linux/slab.h>
9#include <linux/string.h>
10#include <linux/dcache.h>
11#include <linux/sunrpc/sched.h>
12#include <linux/sunrpc/clnt.h>
13#include <linux/nfs_fs.h>
14#include <linux/sched.h>
15#include <linux/wait.h>
16#include <linux/namei.h>
17#include <linux/fsnotify.h>
18
19#include "internal.h"
20#include "nfs4_fs.h"
21#include "iostat.h"
22#include "delegation.h"
23
24#include "nfstrace.h"
25
26/**
27 * nfs_free_unlinkdata - release data from a sillydelete operation.
28 * @data: pointer to unlink structure.
29 */
30static void
31nfs_free_unlinkdata(struct nfs_unlinkdata *data)
32{
33 put_rpccred(data->cred);
34 kfree(data->args.name.name);
35 kfree(data);
36}
37
38/**
39 * nfs_async_unlink_done - Sillydelete post-processing
40 * @task: rpc_task of the sillydelete
41 *
42 * Do the directory attribute update.
43 */
44static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
45{
46 struct nfs_unlinkdata *data = calldata;
47 struct inode *dir = d_inode(data->dentry->d_parent);
48
49 trace_nfs_sillyrename_unlink(data, task->tk_status);
50 if (!NFS_PROTO(dir)->unlink_done(task, dir))
51 rpc_restart_call_prepare(task);
52}
53
54/**
55 * nfs_async_unlink_release - Release the sillydelete data.
56 * @task: rpc_task of the sillydelete
57 *
58 * We need to call nfs_put_unlinkdata as a 'tk_release' task since the
59 * rpc_task would be freed too.
60 */
61static void nfs_async_unlink_release(void *calldata)
62{
63 struct nfs_unlinkdata *data = calldata;
64 struct dentry *dentry = data->dentry;
65 struct super_block *sb = dentry->d_sb;
66
67 up_read_non_owner(&NFS_I(d_inode(dentry->d_parent))->rmdir_sem);
68 d_lookup_done(dentry);
69 nfs_free_unlinkdata(data);
70 dput(dentry);
71 nfs_sb_deactive(sb);
72}
73
74static void nfs_unlink_prepare(struct rpc_task *task, void *calldata)
75{
76 struct nfs_unlinkdata *data = calldata;
77 struct inode *dir = d_inode(data->dentry->d_parent);
78 NFS_PROTO(dir)->unlink_rpc_prepare(task, data);
79}
80
81static const struct rpc_call_ops nfs_unlink_ops = {
82 .rpc_call_done = nfs_async_unlink_done,
83 .rpc_release = nfs_async_unlink_release,
84 .rpc_call_prepare = nfs_unlink_prepare,
85};
86
87static void nfs_do_call_unlink(struct nfs_unlinkdata *data)
88{
89 struct rpc_message msg = {
90 .rpc_argp = &data->args,
91 .rpc_resp = &data->res,
92 .rpc_cred = data->cred,
93 };
94 struct rpc_task_setup task_setup_data = {
95 .rpc_message = &msg,
96 .callback_ops = &nfs_unlink_ops,
97 .callback_data = data,
98 .workqueue = nfsiod_workqueue,
99 .flags = RPC_TASK_ASYNC,
100 };
101 struct rpc_task *task;
102 struct inode *dir = d_inode(data->dentry->d_parent);
103 nfs_sb_active(dir->i_sb);
104 data->args.fh = NFS_FH(dir);
105 nfs_fattr_init(data->res.dir_attr);
106
107 NFS_PROTO(dir)->unlink_setup(&msg, dir);
108
109 task_setup_data.rpc_client = NFS_CLIENT(dir);
110 task = rpc_run_task(&task_setup_data);
111 if (!IS_ERR(task))
112 rpc_put_task_async(task);
113}
114
115static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
116{
117 struct inode *dir = d_inode(dentry->d_parent);
118 struct dentry *alias;
119
120 down_read_non_owner(&NFS_I(dir)->rmdir_sem);
121 alias = d_alloc_parallel(dentry->d_parent, &data->args.name, &data->wq);
122 if (IS_ERR(alias)) {
123 up_read_non_owner(&NFS_I(dir)->rmdir_sem);
124 return 0;
125 }
126 if (!d_in_lookup(alias)) {
127 int ret;
128 void *devname_garbage = NULL;
129
130 /*
131 * Hey, we raced with lookup... See if we need to transfer
132 * the sillyrename information to the aliased dentry.
133 */
134 spin_lock(&alias->d_lock);
135 if (d_really_is_positive(alias) &&
136 !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
137 devname_garbage = alias->d_fsdata;
138 alias->d_fsdata = data;
139 alias->d_flags |= DCACHE_NFSFS_RENAMED;
140 ret = 1;
141 } else
142 ret = 0;
143 spin_unlock(&alias->d_lock);
144 dput(alias);
145 up_read_non_owner(&NFS_I(dir)->rmdir_sem);
146 /*
147 * If we'd displaced old cached devname, free it. At that
148 * point dentry is definitely not a root, so we won't need
149 * that anymore.
150 */
151 kfree(devname_garbage);
152 return ret;
153 }
154 data->dentry = alias;
155 nfs_do_call_unlink(data);
156 return 1;
157}
158
159/**
160 * nfs_async_unlink - asynchronous unlinking of a file
161 * @dir: parent directory of dentry
162 * @dentry: dentry to unlink
163 */
164static int
165nfs_async_unlink(struct dentry *dentry, const struct qstr *name)
166{
167 struct nfs_unlinkdata *data;
168 int status = -ENOMEM;
169 void *devname_garbage = NULL;
170
171 data = kzalloc(sizeof(*data), GFP_KERNEL);
172 if (data == NULL)
173 goto out;
174 data->args.name.name = kstrdup(name->name, GFP_KERNEL);
175 if (!data->args.name.name)
176 goto out_free;
177 data->args.name.len = name->len;
178
179 data->cred = rpc_lookup_cred();
180 if (IS_ERR(data->cred)) {
181 status = PTR_ERR(data->cred);
182 goto out_free_name;
183 }
184 data->res.dir_attr = &data->dir_attr;
185 init_waitqueue_head(&data->wq);
186
187 status = -EBUSY;
188 spin_lock(&dentry->d_lock);
189 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
190 goto out_unlock;
191 dentry->d_flags |= DCACHE_NFSFS_RENAMED;
192 devname_garbage = dentry->d_fsdata;
193 dentry->d_fsdata = data;
194 spin_unlock(&dentry->d_lock);
195 /*
196 * If we'd displaced old cached devname, free it. At that
197 * point dentry is definitely not a root, so we won't need
198 * that anymore.
199 */
200 kfree(devname_garbage);
201 return 0;
202out_unlock:
203 spin_unlock(&dentry->d_lock);
204 put_rpccred(data->cred);
205out_free_name:
206 kfree(data->args.name.name);
207out_free:
208 kfree(data);
209out:
210 return status;
211}
212
213/**
214 * nfs_complete_unlink - Initialize completion of the sillydelete
215 * @dentry: dentry to delete
216 * @inode: inode
217 *
218 * Since we're most likely to be called by dentry_iput(), we
219 * only use the dentry to find the sillydelete. We then copy the name
220 * into the qstr.
221 */
222void
223nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
224{
225 struct nfs_unlinkdata *data;
226
227 spin_lock(&dentry->d_lock);
228 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
229 data = dentry->d_fsdata;
230 dentry->d_fsdata = NULL;
231 spin_unlock(&dentry->d_lock);
232
233 if (NFS_STALE(inode) || !nfs_call_unlink(dentry, data))
234 nfs_free_unlinkdata(data);
235}
236
237/* Cancel a queued async unlink. Called when a sillyrename run fails. */
238static void
239nfs_cancel_async_unlink(struct dentry *dentry)
240{
241 spin_lock(&dentry->d_lock);
242 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
243 struct nfs_unlinkdata *data = dentry->d_fsdata;
244
245 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
246 dentry->d_fsdata = NULL;
247 spin_unlock(&dentry->d_lock);
248 nfs_free_unlinkdata(data);
249 return;
250 }
251 spin_unlock(&dentry->d_lock);
252}
253
254/**
255 * nfs_async_rename_done - Sillyrename post-processing
256 * @task: rpc_task of the sillyrename
257 * @calldata: nfs_renamedata for the sillyrename
258 *
259 * Do the directory attribute updates and the d_move
260 */
261static void nfs_async_rename_done(struct rpc_task *task, void *calldata)
262{
263 struct nfs_renamedata *data = calldata;
264 struct inode *old_dir = data->old_dir;
265 struct inode *new_dir = data->new_dir;
266 struct dentry *old_dentry = data->old_dentry;
267
268 trace_nfs_sillyrename_rename(old_dir, old_dentry,
269 new_dir, data->new_dentry, task->tk_status);
270 if (!NFS_PROTO(old_dir)->rename_done(task, old_dir, new_dir)) {
271 rpc_restart_call_prepare(task);
272 return;
273 }
274
275 if (data->complete)
276 data->complete(task, data);
277}
278
279/**
280 * nfs_async_rename_release - Release the sillyrename data.
281 * @calldata: the struct nfs_renamedata to be released
282 */
283static void nfs_async_rename_release(void *calldata)
284{
285 struct nfs_renamedata *data = calldata;
286 struct super_block *sb = data->old_dir->i_sb;
287
288 if (d_really_is_positive(data->old_dentry))
289 nfs_mark_for_revalidate(d_inode(data->old_dentry));
290
291 dput(data->old_dentry);
292 dput(data->new_dentry);
293 iput(data->old_dir);
294 iput(data->new_dir);
295 nfs_sb_deactive(sb);
296 put_rpccred(data->cred);
297 kfree(data);
298}
299
300static void nfs_rename_prepare(struct rpc_task *task, void *calldata)
301{
302 struct nfs_renamedata *data = calldata;
303 NFS_PROTO(data->old_dir)->rename_rpc_prepare(task, data);
304}
305
306static const struct rpc_call_ops nfs_rename_ops = {
307 .rpc_call_done = nfs_async_rename_done,
308 .rpc_release = nfs_async_rename_release,
309 .rpc_call_prepare = nfs_rename_prepare,
310};
311
312/**
313 * nfs_async_rename - perform an asynchronous rename operation
314 * @old_dir: directory that currently holds the dentry to be renamed
315 * @new_dir: target directory for the rename
316 * @old_dentry: original dentry to be renamed
317 * @new_dentry: dentry to which the old_dentry should be renamed
318 *
319 * It's expected that valid references to the dentries and inodes are held
320 */
321struct rpc_task *
322nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
323 struct dentry *old_dentry, struct dentry *new_dentry,
324 void (*complete)(struct rpc_task *, struct nfs_renamedata *))
325{
326 struct nfs_renamedata *data;
327 struct rpc_message msg = { };
328 struct rpc_task_setup task_setup_data = {
329 .rpc_message = &msg,
330 .callback_ops = &nfs_rename_ops,
331 .workqueue = nfsiod_workqueue,
332 .rpc_client = NFS_CLIENT(old_dir),
333 .flags = RPC_TASK_ASYNC,
334 };
335
336 data = kzalloc(sizeof(*data), GFP_KERNEL);
337 if (data == NULL)
338 return ERR_PTR(-ENOMEM);
339 task_setup_data.callback_data = data;
340
341 data->cred = rpc_lookup_cred();
342 if (IS_ERR(data->cred)) {
343 struct rpc_task *task = ERR_CAST(data->cred);
344 kfree(data);
345 return task;
346 }
347
348 msg.rpc_argp = &data->args;
349 msg.rpc_resp = &data->res;
350 msg.rpc_cred = data->cred;
351
352 /* set up nfs_renamedata */
353 data->old_dir = old_dir;
354 ihold(old_dir);
355 data->new_dir = new_dir;
356 ihold(new_dir);
357 data->old_dentry = dget(old_dentry);
358 data->new_dentry = dget(new_dentry);
359 nfs_fattr_init(&data->old_fattr);
360 nfs_fattr_init(&data->new_fattr);
361 data->complete = complete;
362
363 /* set up nfs_renameargs */
364 data->args.old_dir = NFS_FH(old_dir);
365 data->args.old_name = &old_dentry->d_name;
366 data->args.new_dir = NFS_FH(new_dir);
367 data->args.new_name = &new_dentry->d_name;
368
369 /* set up nfs_renameres */
370 data->res.old_fattr = &data->old_fattr;
371 data->res.new_fattr = &data->new_fattr;
372
373 nfs_sb_active(old_dir->i_sb);
374
375 NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dir);
376
377 return rpc_run_task(&task_setup_data);
378}
379
380/*
381 * Perform tasks needed when a sillyrename is done such as cancelling the
382 * queued async unlink if it failed.
383 */
384static void
385nfs_complete_sillyrename(struct rpc_task *task, struct nfs_renamedata *data)
386{
387 struct dentry *dentry = data->old_dentry;
388
389 if (task->tk_status != 0) {
390 nfs_cancel_async_unlink(dentry);
391 return;
392 }
393
394 /*
395 * vfs_unlink and the like do not issue this when a file is
396 * sillyrenamed, so do it here.
397 */
398 fsnotify_nameremove(dentry, 0);
399}
400
401#define SILLYNAME_PREFIX ".nfs"
402#define SILLYNAME_PREFIX_LEN ((unsigned)sizeof(SILLYNAME_PREFIX) - 1)
403#define SILLYNAME_FILEID_LEN ((unsigned)sizeof(u64) << 1)
404#define SILLYNAME_COUNTER_LEN ((unsigned)sizeof(unsigned int) << 1)
405#define SILLYNAME_LEN (SILLYNAME_PREFIX_LEN + \
406 SILLYNAME_FILEID_LEN + \
407 SILLYNAME_COUNTER_LEN)
408
409/**
410 * nfs_sillyrename - Perform a silly-rename of a dentry
411 * @dir: inode of directory that contains dentry
412 * @dentry: dentry to be sillyrenamed
413 *
414 * NFSv2/3 is stateless and the server doesn't know when the client is
415 * holding a file open. To prevent application problems when a file is
416 * unlinked while it's still open, the client performs a "silly-rename".
417 * That is, it renames the file to a hidden file in the same directory,
418 * and only performs the unlink once the last reference to it is put.
419 *
420 * The final cleanup is done during dentry_iput.
421 *
422 * (Note: NFSv4 is stateful, and has opens, so in theory an NFSv4 server
423 * could take responsibility for keeping open files referenced. The server
424 * would also need to ensure that opened-but-deleted files were kept over
425 * reboots. However, we may not assume a server does so. (RFC 5661
426 * does provide an OPEN4_RESULT_PRESERVE_UNLINKED flag that a server can
427 * use to advertise that it does this; some day we may take advantage of
428 * it.))
429 */
430int
431nfs_sillyrename(struct inode *dir, struct dentry *dentry)
432{
433 static unsigned int sillycounter;
434 unsigned char silly[SILLYNAME_LEN + 1];
435 unsigned long long fileid;
436 struct dentry *sdentry;
437 struct rpc_task *task;
438 int error = -EBUSY;
439
440 dfprintk(VFS, "NFS: silly-rename(%pd2, ct=%d)\n",
441 dentry, d_count(dentry));
442 nfs_inc_stats(dir, NFSIOS_SILLYRENAME);
443
444 /*
445 * We don't allow a dentry to be silly-renamed twice.
446 */
447 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
448 goto out;
449
450 fileid = NFS_FILEID(d_inode(dentry));
451
452 /* Return delegation in anticipation of the rename */
453 NFS_PROTO(d_inode(dentry))->return_delegation(d_inode(dentry));
454
455 sdentry = NULL;
456 do {
457 int slen;
458 dput(sdentry);
459 sillycounter++;
460 slen = scnprintf(silly, sizeof(silly),
461 SILLYNAME_PREFIX "%0*llx%0*x",
462 SILLYNAME_FILEID_LEN, fileid,
463 SILLYNAME_COUNTER_LEN, sillycounter);
464
465 dfprintk(VFS, "NFS: trying to rename %pd to %s\n",
466 dentry, silly);
467
468 sdentry = lookup_one_len(silly, dentry->d_parent, slen);
469 /*
470 * N.B. Better to return EBUSY here ... it could be
471 * dangerous to delete the file while it's in use.
472 */
473 if (IS_ERR(sdentry))
474 goto out;
475 } while (d_inode(sdentry) != NULL); /* need negative lookup */
476
477 /* queue unlink first. Can't do this from rpc_release as it
478 * has to allocate memory
479 */
480 error = nfs_async_unlink(dentry, &sdentry->d_name);
481 if (error)
482 goto out_dput;
483
484 /* run the rename task, undo unlink if it fails */
485 task = nfs_async_rename(dir, dir, dentry, sdentry,
486 nfs_complete_sillyrename);
487 if (IS_ERR(task)) {
488 error = -EBUSY;
489 nfs_cancel_async_unlink(dentry);
490 goto out_dput;
491 }
492
493 /* wait for the RPC task to complete, unless a SIGKILL intervenes */
494 error = rpc_wait_for_completion_task(task);
495 if (error == 0)
496 error = task->tk_status;
497 switch (error) {
498 case 0:
499 /* The rename succeeded */
500 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
501 d_move(dentry, sdentry);
502 break;
503 case -ERESTARTSYS:
504 /* The result of the rename is unknown. Play it safe by
505 * forcing a new lookup */
506 d_drop(dentry);
507 d_drop(sdentry);
508 }
509 rpc_put_task(task);
510out_dput:
511 dput(sdentry);
512out:
513 return error;
514}