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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
106 if (nfs_server_capable(inode, NFS_CAP_MOVEABLE))
107 task_setup_data.flags |= RPC_TASK_MOVEABLE;
108
109 nfs_sb_active(dir->i_sb);
110 data->args.fh = NFS_FH(dir);
111 nfs_fattr_init(data->res.dir_attr);
112
113 NFS_PROTO(dir)->unlink_setup(&msg, data->dentry, inode);
114
115 task_setup_data.rpc_client = NFS_CLIENT(dir);
116 task = rpc_run_task(&task_setup_data);
117 if (!IS_ERR(task))
118 rpc_put_task_async(task);
119}
120
121static int nfs_call_unlink(struct dentry *dentry, struct inode *inode, struct nfs_unlinkdata *data)
122{
123 struct inode *dir = d_inode(dentry->d_parent);
124 struct dentry *alias;
125
126 down_read_non_owner(&NFS_I(dir)->rmdir_sem);
127 alias = d_alloc_parallel(dentry->d_parent, &data->args.name, &data->wq);
128 if (IS_ERR(alias)) {
129 up_read_non_owner(&NFS_I(dir)->rmdir_sem);
130 return 0;
131 }
132 if (!d_in_lookup(alias)) {
133 int ret;
134 void *devname_garbage = NULL;
135
136 /*
137 * Hey, we raced with lookup... See if we need to transfer
138 * the sillyrename information to the aliased dentry.
139 */
140 spin_lock(&alias->d_lock);
141 if (d_really_is_positive(alias) &&
142 !nfs_compare_fh(NFS_FH(inode), NFS_FH(d_inode(alias))) &&
143 !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
144 devname_garbage = alias->d_fsdata;
145 alias->d_fsdata = data;
146 alias->d_flags |= DCACHE_NFSFS_RENAMED;
147 ret = 1;
148 } else
149 ret = 0;
150 spin_unlock(&alias->d_lock);
151 dput(alias);
152 up_read_non_owner(&NFS_I(dir)->rmdir_sem);
153 /*
154 * If we'd displaced old cached devname, free it. At that
155 * point dentry is definitely not a root, so we won't need
156 * that anymore.
157 */
158 kfree(devname_garbage);
159 return ret;
160 }
161 data->dentry = alias;
162 nfs_do_call_unlink(inode, data);
163 return 1;
164}
165
166/**
167 * nfs_async_unlink - asynchronous unlinking of a file
168 * @dentry: parent directory of dentry
169 * @name: name of dentry to unlink
170 */
171static int
172nfs_async_unlink(struct dentry *dentry, const struct qstr *name)
173{
174 struct nfs_unlinkdata *data;
175 int status = -ENOMEM;
176 void *devname_garbage = NULL;
177
178 data = kzalloc(sizeof(*data), GFP_KERNEL);
179 if (data == NULL)
180 goto out;
181 data->args.name.name = kstrdup(name->name, GFP_KERNEL);
182 if (!data->args.name.name)
183 goto out_free;
184 data->args.name.len = name->len;
185
186 data->cred = get_current_cred();
187 data->res.dir_attr = &data->dir_attr;
188 init_waitqueue_head(&data->wq);
189
190 status = -EBUSY;
191 spin_lock(&dentry->d_lock);
192 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
193 goto out_unlock;
194 dentry->d_flags |= DCACHE_NFSFS_RENAMED;
195 devname_garbage = dentry->d_fsdata;
196 dentry->d_fsdata = data;
197 spin_unlock(&dentry->d_lock);
198 /*
199 * If we'd displaced old cached devname, free it. At that
200 * point dentry is definitely not a root, so we won't need
201 * that anymore.
202 */
203 kfree(devname_garbage);
204 return 0;
205out_unlock:
206 spin_unlock(&dentry->d_lock);
207 put_cred(data->cred);
208 kfree(data->args.name.name);
209out_free:
210 kfree(data);
211out:
212 return status;
213}
214
215/**
216 * nfs_complete_unlink - Initialize completion of the sillydelete
217 * @dentry: dentry to delete
218 * @inode: inode
219 *
220 * Since we're most likely to be called by dentry_iput(), we
221 * only use the dentry to find the sillydelete. We then copy the name
222 * into the qstr.
223 */
224void
225nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
226{
227 struct nfs_unlinkdata *data;
228
229 spin_lock(&dentry->d_lock);
230 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
231 data = dentry->d_fsdata;
232 dentry->d_fsdata = NULL;
233 spin_unlock(&dentry->d_lock);
234
235 NFS_PROTO(inode)->return_delegation(inode);
236
237 if (NFS_STALE(inode) || !nfs_call_unlink(dentry, inode, data))
238 nfs_free_unlinkdata(data);
239}
240
241/* Cancel a queued async unlink. Called when a sillyrename run fails. */
242static void
243nfs_cancel_async_unlink(struct dentry *dentry)
244{
245 spin_lock(&dentry->d_lock);
246 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
247 struct nfs_unlinkdata *data = dentry->d_fsdata;
248
249 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
250 dentry->d_fsdata = NULL;
251 spin_unlock(&dentry->d_lock);
252 nfs_free_unlinkdata(data);
253 return;
254 }
255 spin_unlock(&dentry->d_lock);
256}
257
258/**
259 * nfs_async_rename_done - Sillyrename post-processing
260 * @task: rpc_task of the sillyrename
261 * @calldata: nfs_renamedata for the sillyrename
262 *
263 * Do the directory attribute updates and the d_move
264 */
265static void nfs_async_rename_done(struct rpc_task *task, void *calldata)
266{
267 struct nfs_renamedata *data = calldata;
268 struct inode *old_dir = data->old_dir;
269 struct inode *new_dir = data->new_dir;
270 struct dentry *old_dentry = data->old_dentry;
271
272 trace_nfs_async_rename_done(old_dir, old_dentry,
273 new_dir, data->new_dentry, task->tk_status);
274 if (!NFS_PROTO(old_dir)->rename_done(task, old_dir, new_dir)) {
275 rpc_restart_call_prepare(task);
276 return;
277 }
278
279 if (data->complete)
280 data->complete(task, data);
281}
282
283/**
284 * nfs_async_rename_release - Release the sillyrename data.
285 * @calldata: the struct nfs_renamedata to be released
286 */
287static void nfs_async_rename_release(void *calldata)
288{
289 struct nfs_renamedata *data = calldata;
290 struct super_block *sb = data->old_dir->i_sb;
291
292 if (d_really_is_positive(data->old_dentry))
293 nfs_mark_for_revalidate(d_inode(data->old_dentry));
294
295 /* The result of the rename is unknown. Play it safe by
296 * forcing a new lookup */
297 if (data->cancelled) {
298 spin_lock(&data->old_dir->i_lock);
299 nfs_force_lookup_revalidate(data->old_dir);
300 spin_unlock(&data->old_dir->i_lock);
301 if (data->new_dir != data->old_dir) {
302 spin_lock(&data->new_dir->i_lock);
303 nfs_force_lookup_revalidate(data->new_dir);
304 spin_unlock(&data->new_dir->i_lock);
305 }
306 }
307
308 dput(data->old_dentry);
309 dput(data->new_dentry);
310 iput(data->old_dir);
311 iput(data->new_dir);
312 nfs_sb_deactive(sb);
313 put_cred(data->cred);
314 kfree(data);
315}
316
317static void nfs_rename_prepare(struct rpc_task *task, void *calldata)
318{
319 struct nfs_renamedata *data = calldata;
320 NFS_PROTO(data->old_dir)->rename_rpc_prepare(task, data);
321}
322
323static const struct rpc_call_ops nfs_rename_ops = {
324 .rpc_call_done = nfs_async_rename_done,
325 .rpc_release = nfs_async_rename_release,
326 .rpc_call_prepare = nfs_rename_prepare,
327};
328
329/**
330 * nfs_async_rename - perform an asynchronous rename operation
331 * @old_dir: directory that currently holds the dentry to be renamed
332 * @new_dir: target directory for the rename
333 * @old_dentry: original dentry to be renamed
334 * @new_dentry: dentry to which the old_dentry should be renamed
335 * @complete: Function to run on successful completion
336 *
337 * It's expected that valid references to the dentries and inodes are held
338 */
339struct rpc_task *
340nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
341 struct dentry *old_dentry, struct dentry *new_dentry,
342 void (*complete)(struct rpc_task *, struct nfs_renamedata *))
343{
344 struct nfs_renamedata *data;
345 struct rpc_message msg = { };
346 struct rpc_task_setup task_setup_data = {
347 .rpc_message = &msg,
348 .callback_ops = &nfs_rename_ops,
349 .workqueue = nfsiod_workqueue,
350 .rpc_client = NFS_CLIENT(old_dir),
351 .flags = RPC_TASK_ASYNC | RPC_TASK_CRED_NOREF,
352 };
353
354 if (nfs_server_capable(old_dir, NFS_CAP_MOVEABLE) &&
355 nfs_server_capable(new_dir, NFS_CAP_MOVEABLE))
356 task_setup_data.flags |= RPC_TASK_MOVEABLE;
357
358 data = kzalloc(sizeof(*data), GFP_KERNEL);
359 if (data == NULL)
360 return ERR_PTR(-ENOMEM);
361 task_setup_data.task = &data->task;
362 task_setup_data.callback_data = data;
363
364 data->cred = get_current_cred();
365
366 msg.rpc_argp = &data->args;
367 msg.rpc_resp = &data->res;
368 msg.rpc_cred = data->cred;
369
370 /* set up nfs_renamedata */
371 data->old_dir = old_dir;
372 ihold(old_dir);
373 data->new_dir = new_dir;
374 ihold(new_dir);
375 data->old_dentry = dget(old_dentry);
376 data->new_dentry = dget(new_dentry);
377 nfs_fattr_init(&data->old_fattr);
378 nfs_fattr_init(&data->new_fattr);
379 data->complete = complete;
380
381 /* set up nfs_renameargs */
382 data->args.old_dir = NFS_FH(old_dir);
383 data->args.old_name = &old_dentry->d_name;
384 data->args.new_dir = NFS_FH(new_dir);
385 data->args.new_name = &new_dentry->d_name;
386
387 /* set up nfs_renameres */
388 data->res.old_fattr = &data->old_fattr;
389 data->res.new_fattr = &data->new_fattr;
390
391 nfs_sb_active(old_dir->i_sb);
392
393 NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dentry, new_dentry);
394
395 return rpc_run_task(&task_setup_data);
396}
397
398/*
399 * Perform tasks needed when a sillyrename is done such as cancelling the
400 * queued async unlink if it failed.
401 */
402static void
403nfs_complete_sillyrename(struct rpc_task *task, struct nfs_renamedata *data)
404{
405 struct dentry *dentry = data->old_dentry;
406
407 if (task->tk_status != 0) {
408 nfs_cancel_async_unlink(dentry);
409 return;
410 }
411}
412
413#define SILLYNAME_PREFIX ".nfs"
414#define SILLYNAME_PREFIX_LEN ((unsigned)sizeof(SILLYNAME_PREFIX) - 1)
415#define SILLYNAME_FILEID_LEN ((unsigned)sizeof(u64) << 1)
416#define SILLYNAME_COUNTER_LEN ((unsigned)sizeof(unsigned int) << 1)
417#define SILLYNAME_LEN (SILLYNAME_PREFIX_LEN + \
418 SILLYNAME_FILEID_LEN + \
419 SILLYNAME_COUNTER_LEN)
420
421/**
422 * nfs_sillyrename - Perform a silly-rename of a dentry
423 * @dir: inode of directory that contains dentry
424 * @dentry: dentry to be sillyrenamed
425 *
426 * NFSv2/3 is stateless and the server doesn't know when the client is
427 * holding a file open. To prevent application problems when a file is
428 * unlinked while it's still open, the client performs a "silly-rename".
429 * That is, it renames the file to a hidden file in the same directory,
430 * and only performs the unlink once the last reference to it is put.
431 *
432 * The final cleanup is done during dentry_iput.
433 *
434 * (Note: NFSv4 is stateful, and has opens, so in theory an NFSv4 server
435 * could take responsibility for keeping open files referenced. The server
436 * would also need to ensure that opened-but-deleted files were kept over
437 * reboots. However, we may not assume a server does so. (RFC 5661
438 * does provide an OPEN4_RESULT_PRESERVE_UNLINKED flag that a server can
439 * use to advertise that it does this; some day we may take advantage of
440 * it.))
441 */
442int
443nfs_sillyrename(struct inode *dir, struct dentry *dentry)
444{
445 static unsigned int sillycounter;
446 unsigned char silly[SILLYNAME_LEN + 1];
447 unsigned long long fileid;
448 struct dentry *sdentry;
449 struct inode *inode = d_inode(dentry);
450 struct rpc_task *task;
451 int error = -EBUSY;
452
453 dfprintk(VFS, "NFS: silly-rename(%pd2, ct=%d)\n",
454 dentry, d_count(dentry));
455 nfs_inc_stats(dir, NFSIOS_SILLYRENAME);
456
457 /*
458 * We don't allow a dentry to be silly-renamed twice.
459 */
460 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
461 goto out;
462
463 fileid = NFS_FILEID(d_inode(dentry));
464
465 sdentry = NULL;
466 do {
467 int slen;
468 dput(sdentry);
469 sillycounter++;
470 slen = scnprintf(silly, sizeof(silly),
471 SILLYNAME_PREFIX "%0*llx%0*x",
472 SILLYNAME_FILEID_LEN, fileid,
473 SILLYNAME_COUNTER_LEN, sillycounter);
474
475 dfprintk(VFS, "NFS: trying to rename %pd to %s\n",
476 dentry, silly);
477
478 sdentry = lookup_one_len(silly, dentry->d_parent, slen);
479 /*
480 * N.B. Better to return EBUSY here ... it could be
481 * dangerous to delete the file while it's in use.
482 */
483 if (IS_ERR(sdentry))
484 goto out;
485 } while (d_inode(sdentry) != NULL); /* need negative lookup */
486
487 ihold(inode);
488
489 /* queue unlink first. Can't do this from rpc_release as it
490 * has to allocate memory
491 */
492 error = nfs_async_unlink(dentry, &sdentry->d_name);
493 if (error)
494 goto out_dput;
495
496 /* run the rename task, undo unlink if it fails */
497 task = nfs_async_rename(dir, dir, dentry, sdentry,
498 nfs_complete_sillyrename);
499 if (IS_ERR(task)) {
500 error = -EBUSY;
501 nfs_cancel_async_unlink(dentry);
502 goto out_dput;
503 }
504
505 /* wait for the RPC task to complete, unless a SIGKILL intervenes */
506 error = rpc_wait_for_completion_task(task);
507 if (error == 0)
508 error = task->tk_status;
509 switch (error) {
510 case 0:
511 /* The rename succeeded */
512 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
513 spin_lock(&inode->i_lock);
514 NFS_I(inode)->attr_gencount = nfs_inc_attr_generation_counter();
515 nfs_set_cache_invalid(inode, NFS_INO_INVALID_CHANGE |
516 NFS_INO_INVALID_CTIME |
517 NFS_INO_REVAL_FORCED);
518 spin_unlock(&inode->i_lock);
519 d_move(dentry, sdentry);
520 break;
521 case -ERESTARTSYS:
522 /* The result of the rename is unknown. Play it safe by
523 * forcing a new lookup */
524 d_drop(dentry);
525 d_drop(sdentry);
526 }
527 rpc_put_task(task);
528out_dput:
529 iput(inode);
530 dput(sdentry);
531out:
532 return error;
533}
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}