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