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