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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_rpccred(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 *
43 * Do the directory attribute update.
44 */
45static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
46{
47 struct nfs_unlinkdata *data = calldata;
48 struct inode *dir = d_inode(data->dentry->d_parent);
49
50 trace_nfs_sillyrename_unlink(data, task->tk_status);
51 if (!NFS_PROTO(dir)->unlink_done(task, dir))
52 rpc_restart_call_prepare(task);
53}
54
55/**
56 * nfs_async_unlink_release - Release the sillydelete data.
57 * @task: rpc_task of the sillydelete
58 *
59 * We need to call nfs_put_unlinkdata as a 'tk_release' task since the
60 * rpc_task would be freed too.
61 */
62static void nfs_async_unlink_release(void *calldata)
63{
64 struct nfs_unlinkdata *data = calldata;
65 struct dentry *dentry = data->dentry;
66 struct super_block *sb = dentry->d_sb;
67
68 up_read_non_owner(&NFS_I(d_inode(dentry->d_parent))->rmdir_sem);
69 d_lookup_done(dentry);
70 nfs_free_unlinkdata(data);
71 dput(dentry);
72 nfs_sb_deactive(sb);
73}
74
75static void nfs_unlink_prepare(struct rpc_task *task, void *calldata)
76{
77 struct nfs_unlinkdata *data = calldata;
78 struct inode *dir = d_inode(data->dentry->d_parent);
79 NFS_PROTO(dir)->unlink_rpc_prepare(task, data);
80}
81
82static const struct rpc_call_ops nfs_unlink_ops = {
83 .rpc_call_done = nfs_async_unlink_done,
84 .rpc_release = nfs_async_unlink_release,
85 .rpc_call_prepare = nfs_unlink_prepare,
86};
87
88static void nfs_do_call_unlink(struct nfs_unlinkdata *data)
89{
90 struct rpc_message msg = {
91 .rpc_argp = &data->args,
92 .rpc_resp = &data->res,
93 .rpc_cred = data->cred,
94 };
95 struct rpc_task_setup task_setup_data = {
96 .rpc_message = &msg,
97 .callback_ops = &nfs_unlink_ops,
98 .callback_data = data,
99 .workqueue = nfsiod_workqueue,
100 .flags = RPC_TASK_ASYNC,
101 };
102 struct rpc_task *task;
103 struct inode *dir = d_inode(data->dentry->d_parent);
104 nfs_sb_active(dir->i_sb);
105 data->args.fh = NFS_FH(dir);
106 nfs_fattr_init(data->res.dir_attr);
107
108 NFS_PROTO(dir)->unlink_setup(&msg, data->dentry);
109
110 task_setup_data.rpc_client = NFS_CLIENT(dir);
111 task = rpc_run_task(&task_setup_data);
112 if (!IS_ERR(task))
113 rpc_put_task_async(task);
114}
115
116static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
117{
118 struct inode *dir = d_inode(dentry->d_parent);
119 struct dentry *alias;
120
121 down_read_non_owner(&NFS_I(dir)->rmdir_sem);
122 alias = d_alloc_parallel(dentry->d_parent, &data->args.name, &data->wq);
123 if (IS_ERR(alias)) {
124 up_read_non_owner(&NFS_I(dir)->rmdir_sem);
125 return 0;
126 }
127 if (!d_in_lookup(alias)) {
128 int ret;
129 void *devname_garbage = NULL;
130
131 /*
132 * Hey, we raced with lookup... See if we need to transfer
133 * the sillyrename information to the aliased dentry.
134 */
135 spin_lock(&alias->d_lock);
136 if (d_really_is_positive(alias) &&
137 !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
138 devname_garbage = alias->d_fsdata;
139 alias->d_fsdata = data;
140 alias->d_flags |= DCACHE_NFSFS_RENAMED;
141 ret = 1;
142 } else
143 ret = 0;
144 spin_unlock(&alias->d_lock);
145 dput(alias);
146 up_read_non_owner(&NFS_I(dir)->rmdir_sem);
147 /*
148 * If we'd displaced old cached devname, free it. At that
149 * point dentry is definitely not a root, so we won't need
150 * that anymore.
151 */
152 kfree(devname_garbage);
153 return ret;
154 }
155 data->dentry = alias;
156 nfs_do_call_unlink(data);
157 return 1;
158}
159
160/**
161 * nfs_async_unlink - asynchronous unlinking of a file
162 * @dir: parent directory of dentry
163 * @dentry: dentry to unlink
164 */
165static int
166nfs_async_unlink(struct dentry *dentry, const struct qstr *name)
167{
168 struct nfs_unlinkdata *data;
169 int status = -ENOMEM;
170 void *devname_garbage = NULL;
171
172 data = kzalloc(sizeof(*data), GFP_KERNEL);
173 if (data == NULL)
174 goto out;
175 data->args.name.name = kstrdup(name->name, GFP_KERNEL);
176 if (!data->args.name.name)
177 goto out_free;
178 data->args.name.len = name->len;
179
180 data->cred = rpc_lookup_cred();
181 if (IS_ERR(data->cred)) {
182 status = PTR_ERR(data->cred);
183 goto out_free_name;
184 }
185 data->res.dir_attr = &data->dir_attr;
186 init_waitqueue_head(&data->wq);
187
188 status = -EBUSY;
189 spin_lock(&dentry->d_lock);
190 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
191 goto out_unlock;
192 dentry->d_flags |= DCACHE_NFSFS_RENAMED;
193 devname_garbage = dentry->d_fsdata;
194 dentry->d_fsdata = data;
195 spin_unlock(&dentry->d_lock);
196 /*
197 * If we'd displaced old cached devname, free it. At that
198 * point dentry is definitely not a root, so we won't need
199 * that anymore.
200 */
201 kfree(devname_garbage);
202 return 0;
203out_unlock:
204 spin_unlock(&dentry->d_lock);
205 put_rpccred(data->cred);
206out_free_name:
207 kfree(data->args.name.name);
208out_free:
209 kfree(data);
210out:
211 return status;
212}
213
214/**
215 * nfs_complete_unlink - Initialize completion of the sillydelete
216 * @dentry: dentry to delete
217 * @inode: inode
218 *
219 * Since we're most likely to be called by dentry_iput(), we
220 * only use the dentry to find the sillydelete. We then copy the name
221 * into the qstr.
222 */
223void
224nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
225{
226 struct nfs_unlinkdata *data;
227
228 spin_lock(&dentry->d_lock);
229 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
230 data = dentry->d_fsdata;
231 dentry->d_fsdata = NULL;
232 spin_unlock(&dentry->d_lock);
233
234 if (NFS_STALE(inode) || !nfs_call_unlink(dentry, data))
235 nfs_free_unlinkdata(data);
236}
237
238/* Cancel a queued async unlink. Called when a sillyrename run fails. */
239static void
240nfs_cancel_async_unlink(struct dentry *dentry)
241{
242 spin_lock(&dentry->d_lock);
243 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
244 struct nfs_unlinkdata *data = dentry->d_fsdata;
245
246 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
247 dentry->d_fsdata = NULL;
248 spin_unlock(&dentry->d_lock);
249 nfs_free_unlinkdata(data);
250 return;
251 }
252 spin_unlock(&dentry->d_lock);
253}
254
255/**
256 * nfs_async_rename_done - Sillyrename post-processing
257 * @task: rpc_task of the sillyrename
258 * @calldata: nfs_renamedata for the sillyrename
259 *
260 * Do the directory attribute updates and the d_move
261 */
262static void nfs_async_rename_done(struct rpc_task *task, void *calldata)
263{
264 struct nfs_renamedata *data = calldata;
265 struct inode *old_dir = data->old_dir;
266 struct inode *new_dir = data->new_dir;
267 struct dentry *old_dentry = data->old_dentry;
268
269 trace_nfs_sillyrename_rename(old_dir, old_dentry,
270 new_dir, data->new_dentry, task->tk_status);
271 if (!NFS_PROTO(old_dir)->rename_done(task, old_dir, new_dir)) {
272 rpc_restart_call_prepare(task);
273 return;
274 }
275
276 if (data->complete)
277 data->complete(task, data);
278}
279
280/**
281 * nfs_async_rename_release - Release the sillyrename data.
282 * @calldata: the struct nfs_renamedata to be released
283 */
284static void nfs_async_rename_release(void *calldata)
285{
286 struct nfs_renamedata *data = calldata;
287 struct super_block *sb = data->old_dir->i_sb;
288
289 if (d_really_is_positive(data->old_dentry))
290 nfs_mark_for_revalidate(d_inode(data->old_dentry));
291
292 /* The result of the rename is unknown. Play it safe by
293 * forcing a new lookup */
294 if (data->cancelled) {
295 spin_lock(&data->old_dir->i_lock);
296 nfs_force_lookup_revalidate(data->old_dir);
297 spin_unlock(&data->old_dir->i_lock);
298 if (data->new_dir != data->old_dir) {
299 spin_lock(&data->new_dir->i_lock);
300 nfs_force_lookup_revalidate(data->new_dir);
301 spin_unlock(&data->new_dir->i_lock);
302 }
303 }
304
305 dput(data->old_dentry);
306 dput(data->new_dentry);
307 iput(data->old_dir);
308 iput(data->new_dir);
309 nfs_sb_deactive(sb);
310 put_rpccred(data->cred);
311 kfree(data);
312}
313
314static void nfs_rename_prepare(struct rpc_task *task, void *calldata)
315{
316 struct nfs_renamedata *data = calldata;
317 NFS_PROTO(data->old_dir)->rename_rpc_prepare(task, data);
318}
319
320static const struct rpc_call_ops nfs_rename_ops = {
321 .rpc_call_done = nfs_async_rename_done,
322 .rpc_release = nfs_async_rename_release,
323 .rpc_call_prepare = nfs_rename_prepare,
324};
325
326/**
327 * nfs_async_rename - perform an asynchronous rename operation
328 * @old_dir: directory that currently holds the dentry to be renamed
329 * @new_dir: target directory for the rename
330 * @old_dentry: original dentry to be renamed
331 * @new_dentry: dentry to which the old_dentry should be renamed
332 *
333 * It's expected that valid references to the dentries and inodes are held
334 */
335struct rpc_task *
336nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
337 struct dentry *old_dentry, struct dentry *new_dentry,
338 void (*complete)(struct rpc_task *, struct nfs_renamedata *))
339{
340 struct nfs_renamedata *data;
341 struct rpc_message msg = { };
342 struct rpc_task_setup task_setup_data = {
343 .rpc_message = &msg,
344 .callback_ops = &nfs_rename_ops,
345 .workqueue = nfsiod_workqueue,
346 .rpc_client = NFS_CLIENT(old_dir),
347 .flags = RPC_TASK_ASYNC,
348 };
349
350 data = kzalloc(sizeof(*data), GFP_KERNEL);
351 if (data == NULL)
352 return ERR_PTR(-ENOMEM);
353 task_setup_data.callback_data = data;
354
355 data->cred = rpc_lookup_cred();
356 if (IS_ERR(data->cred)) {
357 struct rpc_task *task = ERR_CAST(data->cred);
358 kfree(data);
359 return task;
360 }
361
362 msg.rpc_argp = &data->args;
363 msg.rpc_resp = &data->res;
364 msg.rpc_cred = data->cred;
365
366 /* set up nfs_renamedata */
367 data->old_dir = old_dir;
368 ihold(old_dir);
369 data->new_dir = new_dir;
370 ihold(new_dir);
371 data->old_dentry = dget(old_dentry);
372 data->new_dentry = dget(new_dentry);
373 nfs_fattr_init(&data->old_fattr);
374 nfs_fattr_init(&data->new_fattr);
375 data->complete = complete;
376
377 /* set up nfs_renameargs */
378 data->args.old_dir = NFS_FH(old_dir);
379 data->args.old_name = &old_dentry->d_name;
380 data->args.new_dir = NFS_FH(new_dir);
381 data->args.new_name = &new_dentry->d_name;
382
383 /* set up nfs_renameres */
384 data->res.old_fattr = &data->old_fattr;
385 data->res.new_fattr = &data->new_fattr;
386
387 nfs_sb_active(old_dir->i_sb);
388
389 NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dentry, new_dentry);
390
391 return rpc_run_task(&task_setup_data);
392}
393
394/*
395 * Perform tasks needed when a sillyrename is done such as cancelling the
396 * queued async unlink if it failed.
397 */
398static void
399nfs_complete_sillyrename(struct rpc_task *task, struct nfs_renamedata *data)
400{
401 struct dentry *dentry = data->old_dentry;
402
403 if (task->tk_status != 0) {
404 nfs_cancel_async_unlink(dentry);
405 return;
406 }
407
408 /*
409 * vfs_unlink and the like do not issue this when a file is
410 * sillyrenamed, so do it here.
411 */
412 fsnotify_nameremove(dentry, 0);
413}
414
415#define SILLYNAME_PREFIX ".nfs"
416#define SILLYNAME_PREFIX_LEN ((unsigned)sizeof(SILLYNAME_PREFIX) - 1)
417#define SILLYNAME_FILEID_LEN ((unsigned)sizeof(u64) << 1)
418#define SILLYNAME_COUNTER_LEN ((unsigned)sizeof(unsigned int) << 1)
419#define SILLYNAME_LEN (SILLYNAME_PREFIX_LEN + \
420 SILLYNAME_FILEID_LEN + \
421 SILLYNAME_COUNTER_LEN)
422
423/**
424 * nfs_sillyrename - Perform a silly-rename of a dentry
425 * @dir: inode of directory that contains dentry
426 * @dentry: dentry to be sillyrenamed
427 *
428 * NFSv2/3 is stateless and the server doesn't know when the client is
429 * holding a file open. To prevent application problems when a file is
430 * unlinked while it's still open, the client performs a "silly-rename".
431 * That is, it renames the file to a hidden file in the same directory,
432 * and only performs the unlink once the last reference to it is put.
433 *
434 * The final cleanup is done during dentry_iput.
435 *
436 * (Note: NFSv4 is stateful, and has opens, so in theory an NFSv4 server
437 * could take responsibility for keeping open files referenced. The server
438 * would also need to ensure that opened-but-deleted files were kept over
439 * reboots. However, we may not assume a server does so. (RFC 5661
440 * does provide an OPEN4_RESULT_PRESERVE_UNLINKED flag that a server can
441 * use to advertise that it does this; some day we may take advantage of
442 * it.))
443 */
444int
445nfs_sillyrename(struct inode *dir, struct dentry *dentry)
446{
447 static unsigned int sillycounter;
448 unsigned char silly[SILLYNAME_LEN + 1];
449 unsigned long long fileid;
450 struct dentry *sdentry;
451 struct rpc_task *task;
452 int error = -EBUSY;
453
454 dfprintk(VFS, "NFS: silly-rename(%pd2, ct=%d)\n",
455 dentry, d_count(dentry));
456 nfs_inc_stats(dir, NFSIOS_SILLYRENAME);
457
458 /*
459 * We don't allow a dentry to be silly-renamed twice.
460 */
461 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
462 goto out;
463
464 fileid = NFS_FILEID(d_inode(dentry));
465
466 sdentry = NULL;
467 do {
468 int slen;
469 dput(sdentry);
470 sillycounter++;
471 slen = scnprintf(silly, sizeof(silly),
472 SILLYNAME_PREFIX "%0*llx%0*x",
473 SILLYNAME_FILEID_LEN, fileid,
474 SILLYNAME_COUNTER_LEN, sillycounter);
475
476 dfprintk(VFS, "NFS: trying to rename %pd to %s\n",
477 dentry, silly);
478
479 sdentry = lookup_one_len(silly, dentry->d_parent, slen);
480 /*
481 * N.B. Better to return EBUSY here ... it could be
482 * dangerous to delete the file while it's in use.
483 */
484 if (IS_ERR(sdentry))
485 goto out;
486 } while (d_inode(sdentry) != NULL); /* need negative lookup */
487
488 /* queue unlink first. Can't do this from rpc_release as it
489 * has to allocate memory
490 */
491 error = nfs_async_unlink(dentry, &sdentry->d_name);
492 if (error)
493 goto out_dput;
494
495 /* run the rename task, undo unlink if it fails */
496 task = nfs_async_rename(dir, dir, dentry, sdentry,
497 nfs_complete_sillyrename);
498 if (IS_ERR(task)) {
499 error = -EBUSY;
500 nfs_cancel_async_unlink(dentry);
501 goto out_dput;
502 }
503
504 /* wait for the RPC task to complete, unless a SIGKILL intervenes */
505 error = rpc_wait_for_completion_task(task);
506 if (error == 0)
507 error = task->tk_status;
508 switch (error) {
509 case 0:
510 /* The rename succeeded */
511 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
512 d_move(dentry, sdentry);
513 break;
514 case -ERESTARTSYS:
515 /* The result of the rename is unknown. Play it safe by
516 * forcing a new lookup */
517 d_drop(dentry);
518 d_drop(sdentry);
519 }
520 rpc_put_task(task);
521out_dput:
522 dput(sdentry);
523out:
524 return error;
525}
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 iput(data->dir);
34 put_rpccred(data->cred);
35 kfree(data->args.name.name);
36 kfree(data);
37}
38
39#define NAME_ALLOC_LEN(len) ((len+16) & ~15)
40/**
41 * nfs_copy_dname - copy dentry name to data structure
42 * @dentry: pointer to dentry
43 * @data: nfs_unlinkdata
44 */
45static int nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
46{
47 char *str;
48 int len = dentry->d_name.len;
49
50 str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
51 if (!str)
52 return -ENOMEM;
53 data->args.name.len = len;
54 data->args.name.name = str;
55 return 0;
56}
57
58static void nfs_free_dname(struct nfs_unlinkdata *data)
59{
60 kfree(data->args.name.name);
61 data->args.name.name = NULL;
62 data->args.name.len = 0;
63}
64
65static void nfs_dec_sillycount(struct inode *dir)
66{
67 struct nfs_inode *nfsi = NFS_I(dir);
68 if (atomic_dec_return(&nfsi->silly_count) == 1)
69 wake_up(&nfsi->waitqueue);
70}
71
72/**
73 * nfs_async_unlink_done - Sillydelete post-processing
74 * @task: rpc_task of the sillydelete
75 *
76 * Do the directory attribute update.
77 */
78static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
79{
80 struct nfs_unlinkdata *data = calldata;
81 struct inode *dir = data->dir;
82
83 trace_nfs_sillyrename_unlink(data, task->tk_status);
84 if (!NFS_PROTO(dir)->unlink_done(task, dir))
85 rpc_restart_call_prepare(task);
86}
87
88/**
89 * nfs_async_unlink_release - Release the sillydelete data.
90 * @task: rpc_task of the sillydelete
91 *
92 * We need to call nfs_put_unlinkdata as a 'tk_release' task since the
93 * rpc_task would be freed too.
94 */
95static void nfs_async_unlink_release(void *calldata)
96{
97 struct nfs_unlinkdata *data = calldata;
98 struct super_block *sb = data->dir->i_sb;
99
100 nfs_dec_sillycount(data->dir);
101 nfs_free_unlinkdata(data);
102 nfs_sb_deactive(sb);
103}
104
105static void nfs_unlink_prepare(struct rpc_task *task, void *calldata)
106{
107 struct nfs_unlinkdata *data = calldata;
108 NFS_PROTO(data->dir)->unlink_rpc_prepare(task, data);
109}
110
111static const struct rpc_call_ops nfs_unlink_ops = {
112 .rpc_call_done = nfs_async_unlink_done,
113 .rpc_release = nfs_async_unlink_release,
114 .rpc_call_prepare = nfs_unlink_prepare,
115};
116
117static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct nfs_unlinkdata *data)
118{
119 struct rpc_message msg = {
120 .rpc_argp = &data->args,
121 .rpc_resp = &data->res,
122 .rpc_cred = data->cred,
123 };
124 struct rpc_task_setup task_setup_data = {
125 .rpc_message = &msg,
126 .callback_ops = &nfs_unlink_ops,
127 .callback_data = data,
128 .workqueue = nfsiod_workqueue,
129 .flags = RPC_TASK_ASYNC,
130 };
131 struct rpc_task *task;
132 struct dentry *alias;
133
134 alias = d_lookup(parent, &data->args.name);
135 if (alias != NULL) {
136 int ret;
137 void *devname_garbage = NULL;
138
139 /*
140 * Hey, we raced with lookup... See if we need to transfer
141 * the sillyrename information to the aliased dentry.
142 */
143 nfs_free_dname(data);
144 ret = nfs_copy_dname(alias, data);
145 spin_lock(&alias->d_lock);
146 if (ret == 0 && alias->d_inode != NULL &&
147 !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
148 devname_garbage = alias->d_fsdata;
149 alias->d_fsdata = data;
150 alias->d_flags |= DCACHE_NFSFS_RENAMED;
151 ret = 1;
152 } else
153 ret = 0;
154 spin_unlock(&alias->d_lock);
155 nfs_dec_sillycount(dir);
156 dput(alias);
157 /*
158 * If we'd displaced old cached devname, free it. At that
159 * point dentry is definitely not a root, so we won't need
160 * that anymore.
161 */
162 kfree(devname_garbage);
163 return ret;
164 }
165 data->dir = igrab(dir);
166 if (!data->dir) {
167 nfs_dec_sillycount(dir);
168 return 0;
169 }
170 nfs_sb_active(dir->i_sb);
171 data->args.fh = NFS_FH(dir);
172 nfs_fattr_init(data->res.dir_attr);
173
174 NFS_PROTO(dir)->unlink_setup(&msg, dir);
175
176 task_setup_data.rpc_client = NFS_CLIENT(dir);
177 task = rpc_run_task(&task_setup_data);
178 if (!IS_ERR(task))
179 rpc_put_task_async(task);
180 return 1;
181}
182
183static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
184{
185 struct dentry *parent;
186 struct inode *dir;
187 int ret = 0;
188
189
190 parent = dget_parent(dentry);
191 if (parent == NULL)
192 goto out_free;
193 dir = parent->d_inode;
194 /* Non-exclusive lock protects against concurrent lookup() calls */
195 spin_lock(&dir->i_lock);
196 if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) {
197 /* Deferred delete */
198 hlist_add_head(&data->list, &NFS_I(dir)->silly_list);
199 spin_unlock(&dir->i_lock);
200 ret = 1;
201 goto out_dput;
202 }
203 spin_unlock(&dir->i_lock);
204 ret = nfs_do_call_unlink(parent, dir, data);
205out_dput:
206 dput(parent);
207out_free:
208 return ret;
209}
210
211void nfs_wait_on_sillyrename(struct dentry *dentry)
212{
213 struct nfs_inode *nfsi = NFS_I(dentry->d_inode);
214
215 wait_event(nfsi->waitqueue, atomic_read(&nfsi->silly_count) <= 1);
216}
217
218void nfs_block_sillyrename(struct dentry *dentry)
219{
220 struct nfs_inode *nfsi = NFS_I(dentry->d_inode);
221
222 wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1);
223}
224
225void nfs_unblock_sillyrename(struct dentry *dentry)
226{
227 struct inode *dir = dentry->d_inode;
228 struct nfs_inode *nfsi = NFS_I(dir);
229 struct nfs_unlinkdata *data;
230
231 atomic_inc(&nfsi->silly_count);
232 spin_lock(&dir->i_lock);
233 while (!hlist_empty(&nfsi->silly_list)) {
234 if (!atomic_inc_not_zero(&nfsi->silly_count))
235 break;
236 data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list);
237 hlist_del(&data->list);
238 spin_unlock(&dir->i_lock);
239 if (nfs_do_call_unlink(dentry, dir, data) == 0)
240 nfs_free_unlinkdata(data);
241 spin_lock(&dir->i_lock);
242 }
243 spin_unlock(&dir->i_lock);
244}
245
246/**
247 * nfs_async_unlink - asynchronous unlinking of a file
248 * @dir: parent directory of dentry
249 * @dentry: dentry to unlink
250 */
251static int
252nfs_async_unlink(struct inode *dir, struct dentry *dentry)
253{
254 struct nfs_unlinkdata *data;
255 int status = -ENOMEM;
256 void *devname_garbage = NULL;
257
258 data = kzalloc(sizeof(*data), GFP_KERNEL);
259 if (data == NULL)
260 goto out;
261
262 data->cred = rpc_lookup_cred();
263 if (IS_ERR(data->cred)) {
264 status = PTR_ERR(data->cred);
265 goto out_free;
266 }
267 data->res.dir_attr = &data->dir_attr;
268
269 status = -EBUSY;
270 spin_lock(&dentry->d_lock);
271 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
272 goto out_unlock;
273 dentry->d_flags |= DCACHE_NFSFS_RENAMED;
274 devname_garbage = dentry->d_fsdata;
275 dentry->d_fsdata = data;
276 spin_unlock(&dentry->d_lock);
277 /*
278 * If we'd displaced old cached devname, free it. At that
279 * point dentry is definitely not a root, so we won't need
280 * that anymore.
281 */
282 kfree(devname_garbage);
283 return 0;
284out_unlock:
285 spin_unlock(&dentry->d_lock);
286 put_rpccred(data->cred);
287out_free:
288 kfree(data);
289out:
290 return status;
291}
292
293/**
294 * nfs_complete_unlink - Initialize completion of the sillydelete
295 * @dentry: dentry to delete
296 * @inode: inode
297 *
298 * Since we're most likely to be called by dentry_iput(), we
299 * only use the dentry to find the sillydelete. We then copy the name
300 * into the qstr.
301 */
302void
303nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
304{
305 struct nfs_unlinkdata *data = NULL;
306
307 spin_lock(&dentry->d_lock);
308 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
309 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
310 data = dentry->d_fsdata;
311 dentry->d_fsdata = NULL;
312 }
313 spin_unlock(&dentry->d_lock);
314
315 if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data)))
316 nfs_free_unlinkdata(data);
317}
318
319/* Cancel a queued async unlink. Called when a sillyrename run fails. */
320static void
321nfs_cancel_async_unlink(struct dentry *dentry)
322{
323 spin_lock(&dentry->d_lock);
324 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
325 struct nfs_unlinkdata *data = dentry->d_fsdata;
326
327 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
328 dentry->d_fsdata = NULL;
329 spin_unlock(&dentry->d_lock);
330 nfs_free_unlinkdata(data);
331 return;
332 }
333 spin_unlock(&dentry->d_lock);
334}
335
336/**
337 * nfs_async_rename_done - Sillyrename post-processing
338 * @task: rpc_task of the sillyrename
339 * @calldata: nfs_renamedata for the sillyrename
340 *
341 * Do the directory attribute updates and the d_move
342 */
343static void nfs_async_rename_done(struct rpc_task *task, void *calldata)
344{
345 struct nfs_renamedata *data = calldata;
346 struct inode *old_dir = data->old_dir;
347 struct inode *new_dir = data->new_dir;
348 struct dentry *old_dentry = data->old_dentry;
349
350 trace_nfs_sillyrename_rename(old_dir, old_dentry,
351 new_dir, data->new_dentry, task->tk_status);
352 if (!NFS_PROTO(old_dir)->rename_done(task, old_dir, new_dir)) {
353 rpc_restart_call_prepare(task);
354 return;
355 }
356
357 if (data->complete)
358 data->complete(task, data);
359}
360
361/**
362 * nfs_async_rename_release - Release the sillyrename data.
363 * @calldata: the struct nfs_renamedata to be released
364 */
365static void nfs_async_rename_release(void *calldata)
366{
367 struct nfs_renamedata *data = calldata;
368 struct super_block *sb = data->old_dir->i_sb;
369
370 if (data->old_dentry->d_inode)
371 nfs_mark_for_revalidate(data->old_dentry->d_inode);
372
373 dput(data->old_dentry);
374 dput(data->new_dentry);
375 iput(data->old_dir);
376 iput(data->new_dir);
377 nfs_sb_deactive(sb);
378 put_rpccred(data->cred);
379 kfree(data);
380}
381
382static void nfs_rename_prepare(struct rpc_task *task, void *calldata)
383{
384 struct nfs_renamedata *data = calldata;
385 NFS_PROTO(data->old_dir)->rename_rpc_prepare(task, data);
386}
387
388static const struct rpc_call_ops nfs_rename_ops = {
389 .rpc_call_done = nfs_async_rename_done,
390 .rpc_release = nfs_async_rename_release,
391 .rpc_call_prepare = nfs_rename_prepare,
392};
393
394/**
395 * nfs_async_rename - perform an asynchronous rename operation
396 * @old_dir: directory that currently holds the dentry to be renamed
397 * @new_dir: target directory for the rename
398 * @old_dentry: original dentry to be renamed
399 * @new_dentry: dentry to which the old_dentry should be renamed
400 *
401 * It's expected that valid references to the dentries and inodes are held
402 */
403struct rpc_task *
404nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
405 struct dentry *old_dentry, struct dentry *new_dentry,
406 void (*complete)(struct rpc_task *, struct nfs_renamedata *))
407{
408 struct nfs_renamedata *data;
409 struct rpc_message msg = { };
410 struct rpc_task_setup task_setup_data = {
411 .rpc_message = &msg,
412 .callback_ops = &nfs_rename_ops,
413 .workqueue = nfsiod_workqueue,
414 .rpc_client = NFS_CLIENT(old_dir),
415 .flags = RPC_TASK_ASYNC,
416 };
417
418 data = kzalloc(sizeof(*data), GFP_KERNEL);
419 if (data == NULL)
420 return ERR_PTR(-ENOMEM);
421 task_setup_data.callback_data = data;
422
423 data->cred = rpc_lookup_cred();
424 if (IS_ERR(data->cred)) {
425 struct rpc_task *task = ERR_CAST(data->cred);
426 kfree(data);
427 return task;
428 }
429
430 msg.rpc_argp = &data->args;
431 msg.rpc_resp = &data->res;
432 msg.rpc_cred = data->cred;
433
434 /* set up nfs_renamedata */
435 data->old_dir = old_dir;
436 ihold(old_dir);
437 data->new_dir = new_dir;
438 ihold(new_dir);
439 data->old_dentry = dget(old_dentry);
440 data->new_dentry = dget(new_dentry);
441 nfs_fattr_init(&data->old_fattr);
442 nfs_fattr_init(&data->new_fattr);
443 data->complete = complete;
444
445 /* set up nfs_renameargs */
446 data->args.old_dir = NFS_FH(old_dir);
447 data->args.old_name = &old_dentry->d_name;
448 data->args.new_dir = NFS_FH(new_dir);
449 data->args.new_name = &new_dentry->d_name;
450
451 /* set up nfs_renameres */
452 data->res.old_fattr = &data->old_fattr;
453 data->res.new_fattr = &data->new_fattr;
454
455 nfs_sb_active(old_dir->i_sb);
456
457 NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dir);
458
459 return rpc_run_task(&task_setup_data);
460}
461
462/*
463 * Perform tasks needed when a sillyrename is done such as cancelling the
464 * queued async unlink if it failed.
465 */
466static void
467nfs_complete_sillyrename(struct rpc_task *task, struct nfs_renamedata *data)
468{
469 struct dentry *dentry = data->old_dentry;
470
471 if (task->tk_status != 0) {
472 nfs_cancel_async_unlink(dentry);
473 return;
474 }
475
476 /*
477 * vfs_unlink and the like do not issue this when a file is
478 * sillyrenamed, so do it here.
479 */
480 fsnotify_nameremove(dentry, 0);
481}
482
483#define SILLYNAME_PREFIX ".nfs"
484#define SILLYNAME_PREFIX_LEN ((unsigned)sizeof(SILLYNAME_PREFIX) - 1)
485#define SILLYNAME_FILEID_LEN ((unsigned)sizeof(u64) << 1)
486#define SILLYNAME_COUNTER_LEN ((unsigned)sizeof(unsigned int) << 1)
487#define SILLYNAME_LEN (SILLYNAME_PREFIX_LEN + \
488 SILLYNAME_FILEID_LEN + \
489 SILLYNAME_COUNTER_LEN)
490
491/**
492 * nfs_sillyrename - Perform a silly-rename of a dentry
493 * @dir: inode of directory that contains dentry
494 * @dentry: dentry to be sillyrenamed
495 *
496 * NFSv2/3 is stateless and the server doesn't know when the client is
497 * holding a file open. To prevent application problems when a file is
498 * unlinked while it's still open, the client performs a "silly-rename".
499 * That is, it renames the file to a hidden file in the same directory,
500 * and only performs the unlink once the last reference to it is put.
501 *
502 * The final cleanup is done during dentry_iput.
503 *
504 * (Note: NFSv4 is stateful, and has opens, so in theory an NFSv4 server
505 * could take responsibility for keeping open files referenced. The server
506 * would also need to ensure that opened-but-deleted files were kept over
507 * reboots. However, we may not assume a server does so. (RFC 5661
508 * does provide an OPEN4_RESULT_PRESERVE_UNLINKED flag that a server can
509 * use to advertise that it does this; some day we may take advantage of
510 * it.))
511 */
512int
513nfs_sillyrename(struct inode *dir, struct dentry *dentry)
514{
515 static unsigned int sillycounter;
516 unsigned char silly[SILLYNAME_LEN + 1];
517 unsigned long long fileid;
518 struct dentry *sdentry;
519 struct rpc_task *task;
520 int error = -EBUSY;
521
522 dfprintk(VFS, "NFS: silly-rename(%pd2, ct=%d)\n",
523 dentry, d_count(dentry));
524 nfs_inc_stats(dir, NFSIOS_SILLYRENAME);
525
526 /*
527 * We don't allow a dentry to be silly-renamed twice.
528 */
529 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
530 goto out;
531
532 fileid = NFS_FILEID(dentry->d_inode);
533
534 /* Return delegation in anticipation of the rename */
535 NFS_PROTO(dentry->d_inode)->return_delegation(dentry->d_inode);
536
537 sdentry = NULL;
538 do {
539 int slen;
540 dput(sdentry);
541 sillycounter++;
542 slen = scnprintf(silly, sizeof(silly),
543 SILLYNAME_PREFIX "%0*llx%0*x",
544 SILLYNAME_FILEID_LEN, fileid,
545 SILLYNAME_COUNTER_LEN, sillycounter);
546
547 dfprintk(VFS, "NFS: trying to rename %pd to %s\n",
548 dentry, silly);
549
550 sdentry = lookup_one_len(silly, dentry->d_parent, slen);
551 /*
552 * N.B. Better to return EBUSY here ... it could be
553 * dangerous to delete the file while it's in use.
554 */
555 if (IS_ERR(sdentry))
556 goto out;
557 } while (sdentry->d_inode != NULL); /* need negative lookup */
558
559 /* queue unlink first. Can't do this from rpc_release as it
560 * has to allocate memory
561 */
562 error = nfs_async_unlink(dir, dentry);
563 if (error)
564 goto out_dput;
565
566 /* populate unlinkdata with the right dname */
567 error = nfs_copy_dname(sdentry,
568 (struct nfs_unlinkdata *)dentry->d_fsdata);
569 if (error) {
570 nfs_cancel_async_unlink(dentry);
571 goto out_dput;
572 }
573
574 /* run the rename task, undo unlink if it fails */
575 task = nfs_async_rename(dir, dir, dentry, sdentry,
576 nfs_complete_sillyrename);
577 if (IS_ERR(task)) {
578 error = -EBUSY;
579 nfs_cancel_async_unlink(dentry);
580 goto out_dput;
581 }
582
583 /* wait for the RPC task to complete, unless a SIGKILL intervenes */
584 error = rpc_wait_for_completion_task(task);
585 if (error == 0)
586 error = task->tk_status;
587 switch (error) {
588 case 0:
589 /* The rename succeeded */
590 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
591 d_move(dentry, sdentry);
592 break;
593 case -ERESTARTSYS:
594 /* The result of the rename is unknown. Play it safe by
595 * forcing a new lookup */
596 d_drop(dentry);
597 d_drop(sdentry);
598 }
599 rpc_put_task(task);
600out_dput:
601 dput(sdentry);
602out:
603 return error;
604}