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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
18#include "internal.h"
19#include "nfs4_fs.h"
20#include "iostat.h"
21#include "delegation.h"
22
23struct nfs_unlinkdata {
24 struct hlist_node list;
25 struct nfs_removeargs args;
26 struct nfs_removeres res;
27 struct inode *dir;
28 struct rpc_cred *cred;
29 struct nfs_fattr dir_attr;
30};
31
32/**
33 * nfs_free_unlinkdata - release data from a sillydelete operation.
34 * @data: pointer to unlink structure.
35 */
36static void
37nfs_free_unlinkdata(struct nfs_unlinkdata *data)
38{
39 iput(data->dir);
40 put_rpccred(data->cred);
41 kfree(data->args.name.name);
42 kfree(data);
43}
44
45#define NAME_ALLOC_LEN(len) ((len+16) & ~15)
46/**
47 * nfs_copy_dname - copy dentry name to data structure
48 * @dentry: pointer to dentry
49 * @data: nfs_unlinkdata
50 */
51static int nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
52{
53 char *str;
54 int len = dentry->d_name.len;
55
56 str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
57 if (!str)
58 return -ENOMEM;
59 data->args.name.len = len;
60 data->args.name.name = str;
61 return 0;
62}
63
64static void nfs_free_dname(struct nfs_unlinkdata *data)
65{
66 kfree(data->args.name.name);
67 data->args.name.name = NULL;
68 data->args.name.len = 0;
69}
70
71static void nfs_dec_sillycount(struct inode *dir)
72{
73 struct nfs_inode *nfsi = NFS_I(dir);
74 if (atomic_dec_return(&nfsi->silly_count) == 1)
75 wake_up(&nfsi->waitqueue);
76}
77
78/**
79 * nfs_async_unlink_done - Sillydelete post-processing
80 * @task: rpc_task of the sillydelete
81 *
82 * Do the directory attribute update.
83 */
84static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
85{
86 struct nfs_unlinkdata *data = calldata;
87 struct inode *dir = data->dir;
88
89 if (!NFS_PROTO(dir)->unlink_done(task, dir))
90 nfs_restart_rpc(task, NFS_SERVER(dir)->nfs_client);
91}
92
93/**
94 * nfs_async_unlink_release - Release the sillydelete data.
95 * @task: rpc_task of the sillydelete
96 *
97 * We need to call nfs_put_unlinkdata as a 'tk_release' task since the
98 * rpc_task would be freed too.
99 */
100static void nfs_async_unlink_release(void *calldata)
101{
102 struct nfs_unlinkdata *data = calldata;
103 struct super_block *sb = data->dir->i_sb;
104
105 nfs_dec_sillycount(data->dir);
106 nfs_free_unlinkdata(data);
107 nfs_sb_deactive(sb);
108}
109
110#if defined(CONFIG_NFS_V4_1)
111void nfs_unlink_prepare(struct rpc_task *task, void *calldata)
112{
113 struct nfs_unlinkdata *data = calldata;
114 struct nfs_server *server = NFS_SERVER(data->dir);
115
116 if (nfs4_setup_sequence(server, &data->args.seq_args,
117 &data->res.seq_res, 1, task))
118 return;
119 rpc_call_start(task);
120}
121#endif /* CONFIG_NFS_V4_1 */
122
123static const struct rpc_call_ops nfs_unlink_ops = {
124 .rpc_call_done = nfs_async_unlink_done,
125 .rpc_release = nfs_async_unlink_release,
126#if defined(CONFIG_NFS_V4_1)
127 .rpc_call_prepare = nfs_unlink_prepare,
128#endif /* CONFIG_NFS_V4_1 */
129};
130
131static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct nfs_unlinkdata *data)
132{
133 struct rpc_message msg = {
134 .rpc_argp = &data->args,
135 .rpc_resp = &data->res,
136 .rpc_cred = data->cred,
137 };
138 struct rpc_task_setup task_setup_data = {
139 .rpc_message = &msg,
140 .callback_ops = &nfs_unlink_ops,
141 .callback_data = data,
142 .workqueue = nfsiod_workqueue,
143 .flags = RPC_TASK_ASYNC,
144 };
145 struct rpc_task *task;
146 struct dentry *alias;
147
148 alias = d_lookup(parent, &data->args.name);
149 if (alias != NULL) {
150 int ret;
151 void *devname_garbage = NULL;
152
153 /*
154 * Hey, we raced with lookup... See if we need to transfer
155 * the sillyrename information to the aliased dentry.
156 */
157 nfs_free_dname(data);
158 ret = nfs_copy_dname(alias, data);
159 spin_lock(&alias->d_lock);
160 if (ret == 0 && alias->d_inode != NULL &&
161 !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
162 devname_garbage = alias->d_fsdata;
163 alias->d_fsdata = data;
164 alias->d_flags |= DCACHE_NFSFS_RENAMED;
165 ret = 1;
166 } else
167 ret = 0;
168 spin_unlock(&alias->d_lock);
169 nfs_dec_sillycount(dir);
170 dput(alias);
171 /*
172 * If we'd displaced old cached devname, free it. At that
173 * point dentry is definitely not a root, so we won't need
174 * that anymore.
175 */
176 kfree(devname_garbage);
177 return ret;
178 }
179 data->dir = igrab(dir);
180 if (!data->dir) {
181 nfs_dec_sillycount(dir);
182 return 0;
183 }
184 nfs_sb_active(dir->i_sb);
185 data->args.fh = NFS_FH(dir);
186 nfs_fattr_init(data->res.dir_attr);
187
188 NFS_PROTO(dir)->unlink_setup(&msg, dir);
189
190 task_setup_data.rpc_client = NFS_CLIENT(dir);
191 task = rpc_run_task(&task_setup_data);
192 if (!IS_ERR(task))
193 rpc_put_task_async(task);
194 return 1;
195}
196
197static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
198{
199 struct dentry *parent;
200 struct inode *dir;
201 int ret = 0;
202
203
204 parent = dget_parent(dentry);
205 if (parent == NULL)
206 goto out_free;
207 dir = parent->d_inode;
208 /* Non-exclusive lock protects against concurrent lookup() calls */
209 spin_lock(&dir->i_lock);
210 if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) {
211 /* Deferred delete */
212 hlist_add_head(&data->list, &NFS_I(dir)->silly_list);
213 spin_unlock(&dir->i_lock);
214 ret = 1;
215 goto out_dput;
216 }
217 spin_unlock(&dir->i_lock);
218 ret = nfs_do_call_unlink(parent, dir, data);
219out_dput:
220 dput(parent);
221out_free:
222 return ret;
223}
224
225void nfs_block_sillyrename(struct dentry *dentry)
226{
227 struct nfs_inode *nfsi = NFS_I(dentry->d_inode);
228
229 wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1);
230}
231
232void nfs_unblock_sillyrename(struct dentry *dentry)
233{
234 struct inode *dir = dentry->d_inode;
235 struct nfs_inode *nfsi = NFS_I(dir);
236 struct nfs_unlinkdata *data;
237
238 atomic_inc(&nfsi->silly_count);
239 spin_lock(&dir->i_lock);
240 while (!hlist_empty(&nfsi->silly_list)) {
241 if (!atomic_inc_not_zero(&nfsi->silly_count))
242 break;
243 data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list);
244 hlist_del(&data->list);
245 spin_unlock(&dir->i_lock);
246 if (nfs_do_call_unlink(dentry, dir, data) == 0)
247 nfs_free_unlinkdata(data);
248 spin_lock(&dir->i_lock);
249 }
250 spin_unlock(&dir->i_lock);
251}
252
253/**
254 * nfs_async_unlink - asynchronous unlinking of a file
255 * @dir: parent directory of dentry
256 * @dentry: dentry to unlink
257 */
258static int
259nfs_async_unlink(struct inode *dir, struct dentry *dentry)
260{
261 struct nfs_unlinkdata *data;
262 int status = -ENOMEM;
263 void *devname_garbage = NULL;
264
265 data = kzalloc(sizeof(*data), GFP_KERNEL);
266 if (data == NULL)
267 goto out;
268
269 data->cred = rpc_lookup_cred();
270 if (IS_ERR(data->cred)) {
271 status = PTR_ERR(data->cred);
272 goto out_free;
273 }
274 data->res.dir_attr = &data->dir_attr;
275
276 status = -EBUSY;
277 spin_lock(&dentry->d_lock);
278 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
279 goto out_unlock;
280 dentry->d_flags |= DCACHE_NFSFS_RENAMED;
281 devname_garbage = dentry->d_fsdata;
282 dentry->d_fsdata = data;
283 spin_unlock(&dentry->d_lock);
284 /*
285 * If we'd displaced old cached devname, free it. At that
286 * point dentry is definitely not a root, so we won't need
287 * that anymore.
288 */
289 if (devname_garbage)
290 kfree(devname_garbage);
291 return 0;
292out_unlock:
293 spin_unlock(&dentry->d_lock);
294 put_rpccred(data->cred);
295out_free:
296 kfree(data);
297out:
298 return status;
299}
300
301/**
302 * nfs_complete_unlink - Initialize completion of the sillydelete
303 * @dentry: dentry to delete
304 * @inode: inode
305 *
306 * Since we're most likely to be called by dentry_iput(), we
307 * only use the dentry to find the sillydelete. We then copy the name
308 * into the qstr.
309 */
310void
311nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
312{
313 struct nfs_unlinkdata *data = NULL;
314
315 spin_lock(&dentry->d_lock);
316 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
317 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
318 data = dentry->d_fsdata;
319 dentry->d_fsdata = NULL;
320 }
321 spin_unlock(&dentry->d_lock);
322
323 if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data)))
324 nfs_free_unlinkdata(data);
325}
326
327/* Cancel a queued async unlink. Called when a sillyrename run fails. */
328static void
329nfs_cancel_async_unlink(struct dentry *dentry)
330{
331 spin_lock(&dentry->d_lock);
332 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
333 struct nfs_unlinkdata *data = dentry->d_fsdata;
334
335 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
336 dentry->d_fsdata = NULL;
337 spin_unlock(&dentry->d_lock);
338 nfs_free_unlinkdata(data);
339 return;
340 }
341 spin_unlock(&dentry->d_lock);
342}
343
344struct nfs_renamedata {
345 struct nfs_renameargs args;
346 struct nfs_renameres res;
347 struct rpc_cred *cred;
348 struct inode *old_dir;
349 struct dentry *old_dentry;
350 struct nfs_fattr old_fattr;
351 struct inode *new_dir;
352 struct dentry *new_dentry;
353 struct nfs_fattr new_fattr;
354};
355
356/**
357 * nfs_async_rename_done - Sillyrename post-processing
358 * @task: rpc_task of the sillyrename
359 * @calldata: nfs_renamedata for the sillyrename
360 *
361 * Do the directory attribute updates and the d_move
362 */
363static void nfs_async_rename_done(struct rpc_task *task, void *calldata)
364{
365 struct nfs_renamedata *data = calldata;
366 struct inode *old_dir = data->old_dir;
367 struct inode *new_dir = data->new_dir;
368 struct dentry *old_dentry = data->old_dentry;
369 struct dentry *new_dentry = data->new_dentry;
370
371 if (!NFS_PROTO(old_dir)->rename_done(task, old_dir, new_dir)) {
372 nfs_restart_rpc(task, NFS_SERVER(old_dir)->nfs_client);
373 return;
374 }
375
376 if (task->tk_status != 0) {
377 nfs_cancel_async_unlink(old_dentry);
378 return;
379 }
380
381 d_drop(old_dentry);
382 d_drop(new_dentry);
383}
384
385/**
386 * nfs_async_rename_release - Release the sillyrename data.
387 * @calldata: the struct nfs_renamedata to be released
388 */
389static void nfs_async_rename_release(void *calldata)
390{
391 struct nfs_renamedata *data = calldata;
392 struct super_block *sb = data->old_dir->i_sb;
393
394 if (data->old_dentry->d_inode)
395 nfs_mark_for_revalidate(data->old_dentry->d_inode);
396
397 dput(data->old_dentry);
398 dput(data->new_dentry);
399 iput(data->old_dir);
400 iput(data->new_dir);
401 nfs_sb_deactive(sb);
402 put_rpccred(data->cred);
403 kfree(data);
404}
405
406#if defined(CONFIG_NFS_V4_1)
407static void nfs_rename_prepare(struct rpc_task *task, void *calldata)
408{
409 struct nfs_renamedata *data = calldata;
410 struct nfs_server *server = NFS_SERVER(data->old_dir);
411
412 if (nfs4_setup_sequence(server, &data->args.seq_args,
413 &data->res.seq_res, 1, task))
414 return;
415 rpc_call_start(task);
416}
417#endif /* CONFIG_NFS_V4_1 */
418
419static const struct rpc_call_ops nfs_rename_ops = {
420 .rpc_call_done = nfs_async_rename_done,
421 .rpc_release = nfs_async_rename_release,
422#if defined(CONFIG_NFS_V4_1)
423 .rpc_call_prepare = nfs_rename_prepare,
424#endif /* CONFIG_NFS_V4_1 */
425};
426
427/**
428 * nfs_async_rename - perform an asynchronous rename operation
429 * @old_dir: directory that currently holds the dentry to be renamed
430 * @new_dir: target directory for the rename
431 * @old_dentry: original dentry to be renamed
432 * @new_dentry: dentry to which the old_dentry should be renamed
433 *
434 * It's expected that valid references to the dentries and inodes are held
435 */
436static struct rpc_task *
437nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
438 struct dentry *old_dentry, struct dentry *new_dentry)
439{
440 struct nfs_renamedata *data;
441 struct rpc_message msg = { };
442 struct rpc_task_setup task_setup_data = {
443 .rpc_message = &msg,
444 .callback_ops = &nfs_rename_ops,
445 .workqueue = nfsiod_workqueue,
446 .rpc_client = NFS_CLIENT(old_dir),
447 .flags = RPC_TASK_ASYNC,
448 };
449
450 data = kzalloc(sizeof(*data), GFP_KERNEL);
451 if (data == NULL)
452 return ERR_PTR(-ENOMEM);
453 task_setup_data.callback_data = data;
454
455 data->cred = rpc_lookup_cred();
456 if (IS_ERR(data->cred)) {
457 struct rpc_task *task = ERR_CAST(data->cred);
458 kfree(data);
459 return task;
460 }
461
462 msg.rpc_argp = &data->args;
463 msg.rpc_resp = &data->res;
464 msg.rpc_cred = data->cred;
465
466 /* set up nfs_renamedata */
467 data->old_dir = old_dir;
468 ihold(old_dir);
469 data->new_dir = new_dir;
470 ihold(new_dir);
471 data->old_dentry = dget(old_dentry);
472 data->new_dentry = dget(new_dentry);
473 nfs_fattr_init(&data->old_fattr);
474 nfs_fattr_init(&data->new_fattr);
475
476 /* set up nfs_renameargs */
477 data->args.old_dir = NFS_FH(old_dir);
478 data->args.old_name = &old_dentry->d_name;
479 data->args.new_dir = NFS_FH(new_dir);
480 data->args.new_name = &new_dentry->d_name;
481
482 /* set up nfs_renameres */
483 data->res.old_fattr = &data->old_fattr;
484 data->res.new_fattr = &data->new_fattr;
485
486 nfs_sb_active(old_dir->i_sb);
487
488 NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dir);
489
490 return rpc_run_task(&task_setup_data);
491}
492
493/**
494 * nfs_sillyrename - Perform a silly-rename of a dentry
495 * @dir: inode of directory that contains dentry
496 * @dentry: dentry to be sillyrenamed
497 *
498 * NFSv2/3 is stateless and the server doesn't know when the client is
499 * holding a file open. To prevent application problems when a file is
500 * unlinked while it's still open, the client performs a "silly-rename".
501 * That is, it renames the file to a hidden file in the same directory,
502 * and only performs the unlink once the last reference to it is put.
503 *
504 * The final cleanup is done during dentry_iput.
505 *
506 * (Note: NFSv4 is stateful, and has opens, so in theory an NFSv4 server
507 * could take responsibility for keeping open files referenced. The server
508 * would also need to ensure that opened-but-deleted files were kept over
509 * reboots. However, we may not assume a server does so. (RFC 5661
510 * does provide an OPEN4_RESULT_PRESERVE_UNLINKED flag that a server can
511 * use to advertise that it does this; some day we may take advantage of
512 * it.))
513 */
514int
515nfs_sillyrename(struct inode *dir, struct dentry *dentry)
516{
517 static unsigned int sillycounter;
518 const int fileidsize = sizeof(NFS_FILEID(dentry->d_inode))*2;
519 const int countersize = sizeof(sillycounter)*2;
520 const int slen = sizeof(".nfs")+fileidsize+countersize-1;
521 char silly[slen+1];
522 struct dentry *sdentry;
523 struct rpc_task *task;
524 int error = -EIO;
525
526 dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n",
527 dentry->d_parent->d_name.name, dentry->d_name.name,
528 dentry->d_count);
529 nfs_inc_stats(dir, NFSIOS_SILLYRENAME);
530
531 /*
532 * We don't allow a dentry to be silly-renamed twice.
533 */
534 error = -EBUSY;
535 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
536 goto out;
537
538 sprintf(silly, ".nfs%*.*Lx",
539 fileidsize, fileidsize,
540 (unsigned long long)NFS_FILEID(dentry->d_inode));
541
542 /* Return delegation in anticipation of the rename */
543 nfs_inode_return_delegation(dentry->d_inode);
544
545 sdentry = NULL;
546 do {
547 char *suffix = silly + slen - countersize;
548
549 dput(sdentry);
550 sillycounter++;
551 sprintf(suffix, "%*.*x", countersize, countersize, sillycounter);
552
553 dfprintk(VFS, "NFS: trying to rename %s to %s\n",
554 dentry->d_name.name, silly);
555
556 sdentry = lookup_one_len(silly, dentry->d_parent, slen);
557 /*
558 * N.B. Better to return EBUSY here ... it could be
559 * dangerous to delete the file while it's in use.
560 */
561 if (IS_ERR(sdentry))
562 goto out;
563 } while (sdentry->d_inode != NULL); /* need negative lookup */
564
565 /* queue unlink first. Can't do this from rpc_release as it
566 * has to allocate memory
567 */
568 error = nfs_async_unlink(dir, dentry);
569 if (error)
570 goto out_dput;
571
572 /* populate unlinkdata with the right dname */
573 error = nfs_copy_dname(sdentry,
574 (struct nfs_unlinkdata *)dentry->d_fsdata);
575 if (error) {
576 nfs_cancel_async_unlink(dentry);
577 goto out_dput;
578 }
579
580 /* run the rename task, undo unlink if it fails */
581 task = nfs_async_rename(dir, dir, dentry, sdentry);
582 if (IS_ERR(task)) {
583 error = -EBUSY;
584 nfs_cancel_async_unlink(dentry);
585 goto out_dput;
586 }
587
588 /* wait for the RPC task to complete, unless a SIGKILL intervenes */
589 error = rpc_wait_for_completion_task(task);
590 if (error == 0)
591 error = task->tk_status;
592 rpc_put_task(task);
593out_dput:
594 dput(sdentry);
595out:
596 return error;
597}