Loading...
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
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}