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