2 * linux/fs/nfs/unlink.c
4 * nfs sillydelete handling
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>
21 #include "delegation.h"
26 * nfs_free_unlinkdata - release data from a sillydelete operation.
27 * @data: pointer to unlink structure.
30 nfs_free_unlinkdata(struct nfs_unlinkdata
*data
)
33 put_rpccred(data
->cred
);
34 kfree(data
->args
.name
.name
);
38 #define NAME_ALLOC_LEN(len) ((len+16) & ~15)
40 * nfs_copy_dname - copy dentry name to data structure
41 * @dentry: pointer to dentry
42 * @data: nfs_unlinkdata
44 static int nfs_copy_dname(struct dentry
*dentry
, struct nfs_unlinkdata
*data
)
47 int len
= dentry
->d_name
.len
;
49 str
= kmemdup(dentry
->d_name
.name
, NAME_ALLOC_LEN(len
), GFP_KERNEL
);
52 data
->args
.name
.len
= len
;
53 data
->args
.name
.name
= str
;
57 static void nfs_free_dname(struct nfs_unlinkdata
*data
)
59 kfree(data
->args
.name
.name
);
60 data
->args
.name
.name
= NULL
;
61 data
->args
.name
.len
= 0;
64 static void nfs_dec_sillycount(struct inode
*dir
)
66 struct nfs_inode
*nfsi
= NFS_I(dir
);
67 if (atomic_dec_return(&nfsi
->silly_count
) == 1)
68 wake_up(&nfsi
->waitqueue
);
72 * nfs_async_unlink_done - Sillydelete post-processing
73 * @task: rpc_task of the sillydelete
75 * Do the directory attribute update.
77 static void nfs_async_unlink_done(struct rpc_task
*task
, void *calldata
)
79 struct nfs_unlinkdata
*data
= calldata
;
80 struct inode
*dir
= data
->dir
;
82 trace_nfs_sillyrename_unlink(data
, task
->tk_status
);
83 if (!NFS_PROTO(dir
)->unlink_done(task
, dir
))
84 rpc_restart_call_prepare(task
);
88 * nfs_async_unlink_release - Release the sillydelete data.
89 * @task: rpc_task of the sillydelete
91 * We need to call nfs_put_unlinkdata as a 'tk_release' task since the
92 * rpc_task would be freed too.
94 static void nfs_async_unlink_release(void *calldata
)
96 struct nfs_unlinkdata
*data
= calldata
;
97 struct super_block
*sb
= data
->dir
->i_sb
;
99 nfs_dec_sillycount(data
->dir
);
100 nfs_free_unlinkdata(data
);
104 static void nfs_unlink_prepare(struct rpc_task
*task
, void *calldata
)
106 struct nfs_unlinkdata
*data
= calldata
;
107 NFS_PROTO(data
->dir
)->unlink_rpc_prepare(task
, data
);
110 static const struct rpc_call_ops nfs_unlink_ops
= {
111 .rpc_call_done
= nfs_async_unlink_done
,
112 .rpc_release
= nfs_async_unlink_release
,
113 .rpc_call_prepare
= nfs_unlink_prepare
,
116 static int nfs_do_call_unlink(struct dentry
*parent
, struct inode
*dir
, struct nfs_unlinkdata
*data
)
118 struct rpc_message msg
= {
119 .rpc_argp
= &data
->args
,
120 .rpc_resp
= &data
->res
,
121 .rpc_cred
= data
->cred
,
123 struct rpc_task_setup task_setup_data
= {
125 .callback_ops
= &nfs_unlink_ops
,
126 .callback_data
= data
,
127 .workqueue
= nfsiod_workqueue
,
128 .flags
= RPC_TASK_ASYNC
,
130 struct rpc_task
*task
;
131 struct dentry
*alias
;
133 alias
= d_lookup(parent
, &data
->args
.name
);
136 void *devname_garbage
= NULL
;
139 * Hey, we raced with lookup... See if we need to transfer
140 * the sillyrename information to the aliased dentry.
142 nfs_free_dname(data
);
143 ret
= nfs_copy_dname(alias
, data
);
144 spin_lock(&alias
->d_lock
);
145 if (ret
== 0 && alias
->d_inode
!= NULL
&&
146 !(alias
->d_flags
& DCACHE_NFSFS_RENAMED
)) {
147 devname_garbage
= alias
->d_fsdata
;
148 alias
->d_fsdata
= data
;
149 alias
->d_flags
|= DCACHE_NFSFS_RENAMED
;
153 spin_unlock(&alias
->d_lock
);
154 nfs_dec_sillycount(dir
);
157 * If we'd displaced old cached devname, free it. At that
158 * point dentry is definitely not a root, so we won't need
161 kfree(devname_garbage
);
164 data
->dir
= igrab(dir
);
166 nfs_dec_sillycount(dir
);
169 nfs_sb_active(dir
->i_sb
);
170 data
->args
.fh
= NFS_FH(dir
);
171 nfs_fattr_init(data
->res
.dir_attr
);
173 NFS_PROTO(dir
)->unlink_setup(&msg
, dir
);
175 task_setup_data
.rpc_client
= NFS_CLIENT(dir
);
176 task
= rpc_run_task(&task_setup_data
);
178 rpc_put_task_async(task
);
182 static int nfs_call_unlink(struct dentry
*dentry
, struct nfs_unlinkdata
*data
)
184 struct dentry
*parent
;
189 parent
= dget_parent(dentry
);
192 dir
= parent
->d_inode
;
193 /* Non-exclusive lock protects against concurrent lookup() calls */
194 spin_lock(&dir
->i_lock
);
195 if (atomic_inc_not_zero(&NFS_I(dir
)->silly_count
) == 0) {
196 /* Deferred delete */
197 hlist_add_head(&data
->list
, &NFS_I(dir
)->silly_list
);
198 spin_unlock(&dir
->i_lock
);
202 spin_unlock(&dir
->i_lock
);
203 ret
= nfs_do_call_unlink(parent
, dir
, data
);
210 void nfs_wait_on_sillyrename(struct dentry
*dentry
)
212 struct nfs_inode
*nfsi
= NFS_I(dentry
->d_inode
);
214 wait_event(nfsi
->waitqueue
, atomic_read(&nfsi
->silly_count
) <= 1);
217 void nfs_block_sillyrename(struct dentry
*dentry
)
219 struct nfs_inode
*nfsi
= NFS_I(dentry
->d_inode
);
221 wait_event(nfsi
->waitqueue
, atomic_cmpxchg(&nfsi
->silly_count
, 1, 0) == 1);
224 void nfs_unblock_sillyrename(struct dentry
*dentry
)
226 struct inode
*dir
= dentry
->d_inode
;
227 struct nfs_inode
*nfsi
= NFS_I(dir
);
228 struct nfs_unlinkdata
*data
;
230 atomic_inc(&nfsi
->silly_count
);
231 spin_lock(&dir
->i_lock
);
232 while (!hlist_empty(&nfsi
->silly_list
)) {
233 if (!atomic_inc_not_zero(&nfsi
->silly_count
))
235 data
= hlist_entry(nfsi
->silly_list
.first
, struct nfs_unlinkdata
, list
);
236 hlist_del(&data
->list
);
237 spin_unlock(&dir
->i_lock
);
238 if (nfs_do_call_unlink(dentry
, dir
, data
) == 0)
239 nfs_free_unlinkdata(data
);
240 spin_lock(&dir
->i_lock
);
242 spin_unlock(&dir
->i_lock
);
246 * nfs_async_unlink - asynchronous unlinking of a file
247 * @dir: parent directory of dentry
248 * @dentry: dentry to unlink
251 nfs_async_unlink(struct inode
*dir
, struct dentry
*dentry
)
253 struct nfs_unlinkdata
*data
;
254 int status
= -ENOMEM
;
255 void *devname_garbage
= NULL
;
257 data
= kzalloc(sizeof(*data
), GFP_KERNEL
);
261 data
->cred
= rpc_lookup_cred();
262 if (IS_ERR(data
->cred
)) {
263 status
= PTR_ERR(data
->cred
);
266 data
->res
.dir_attr
= &data
->dir_attr
;
269 spin_lock(&dentry
->d_lock
);
270 if (dentry
->d_flags
& DCACHE_NFSFS_RENAMED
)
272 dentry
->d_flags
|= DCACHE_NFSFS_RENAMED
;
273 devname_garbage
= dentry
->d_fsdata
;
274 dentry
->d_fsdata
= data
;
275 spin_unlock(&dentry
->d_lock
);
277 * If we'd displaced old cached devname, free it. At that
278 * point dentry is definitely not a root, so we won't need
281 kfree(devname_garbage
);
284 spin_unlock(&dentry
->d_lock
);
285 put_rpccred(data
->cred
);
293 * nfs_complete_unlink - Initialize completion of the sillydelete
294 * @dentry: dentry to delete
297 * Since we're most likely to be called by dentry_iput(), we
298 * only use the dentry to find the sillydelete. We then copy the name
302 nfs_complete_unlink(struct dentry
*dentry
, struct inode
*inode
)
304 struct nfs_unlinkdata
*data
= NULL
;
306 spin_lock(&dentry
->d_lock
);
307 if (dentry
->d_flags
& DCACHE_NFSFS_RENAMED
) {
308 dentry
->d_flags
&= ~DCACHE_NFSFS_RENAMED
;
309 data
= dentry
->d_fsdata
;
310 dentry
->d_fsdata
= NULL
;
312 spin_unlock(&dentry
->d_lock
);
314 if (data
!= NULL
&& (NFS_STALE(inode
) || !nfs_call_unlink(dentry
, data
)))
315 nfs_free_unlinkdata(data
);
318 /* Cancel a queued async unlink. Called when a sillyrename run fails. */
320 nfs_cancel_async_unlink(struct dentry
*dentry
)
322 spin_lock(&dentry
->d_lock
);
323 if (dentry
->d_flags
& DCACHE_NFSFS_RENAMED
) {
324 struct nfs_unlinkdata
*data
= dentry
->d_fsdata
;
326 dentry
->d_flags
&= ~DCACHE_NFSFS_RENAMED
;
327 dentry
->d_fsdata
= NULL
;
328 spin_unlock(&dentry
->d_lock
);
329 nfs_free_unlinkdata(data
);
332 spin_unlock(&dentry
->d_lock
);
336 * nfs_async_rename_done - Sillyrename post-processing
337 * @task: rpc_task of the sillyrename
338 * @calldata: nfs_renamedata for the sillyrename
340 * Do the directory attribute updates and the d_move
342 static void nfs_async_rename_done(struct rpc_task
*task
, void *calldata
)
344 struct nfs_renamedata
*data
= calldata
;
345 struct inode
*old_dir
= data
->old_dir
;
346 struct inode
*new_dir
= data
->new_dir
;
347 struct dentry
*old_dentry
= data
->old_dentry
;
349 trace_nfs_sillyrename_rename(old_dir
, old_dentry
,
350 new_dir
, data
->new_dentry
, task
->tk_status
);
351 if (!NFS_PROTO(old_dir
)->rename_done(task
, old_dir
, new_dir
)) {
352 rpc_restart_call_prepare(task
);
356 if (task
->tk_status
!= 0)
357 nfs_cancel_async_unlink(old_dentry
);
361 * nfs_async_rename_release - Release the sillyrename data.
362 * @calldata: the struct nfs_renamedata to be released
364 static void nfs_async_rename_release(void *calldata
)
366 struct nfs_renamedata
*data
= calldata
;
367 struct super_block
*sb
= data
->old_dir
->i_sb
;
369 if (data
->old_dentry
->d_inode
)
370 nfs_mark_for_revalidate(data
->old_dentry
->d_inode
);
372 dput(data
->old_dentry
);
373 dput(data
->new_dentry
);
377 put_rpccred(data
->cred
);
381 static void nfs_rename_prepare(struct rpc_task
*task
, void *calldata
)
383 struct nfs_renamedata
*data
= calldata
;
384 NFS_PROTO(data
->old_dir
)->rename_rpc_prepare(task
, data
);
387 static const struct rpc_call_ops nfs_rename_ops
= {
388 .rpc_call_done
= nfs_async_rename_done
,
389 .rpc_release
= nfs_async_rename_release
,
390 .rpc_call_prepare
= nfs_rename_prepare
,
394 * nfs_async_rename - perform an asynchronous rename operation
395 * @old_dir: directory that currently holds the dentry to be renamed
396 * @new_dir: target directory for the rename
397 * @old_dentry: original dentry to be renamed
398 * @new_dentry: dentry to which the old_dentry should be renamed
400 * It's expected that valid references to the dentries and inodes are held
402 static struct rpc_task
*
403 nfs_async_rename(struct inode
*old_dir
, struct inode
*new_dir
,
404 struct dentry
*old_dentry
, struct dentry
*new_dentry
)
406 struct nfs_renamedata
*data
;
407 struct rpc_message msg
= { };
408 struct rpc_task_setup task_setup_data
= {
410 .callback_ops
= &nfs_rename_ops
,
411 .workqueue
= nfsiod_workqueue
,
412 .rpc_client
= NFS_CLIENT(old_dir
),
413 .flags
= RPC_TASK_ASYNC
,
416 data
= kzalloc(sizeof(*data
), GFP_KERNEL
);
418 return ERR_PTR(-ENOMEM
);
419 task_setup_data
.callback_data
= data
;
421 data
->cred
= rpc_lookup_cred();
422 if (IS_ERR(data
->cred
)) {
423 struct rpc_task
*task
= ERR_CAST(data
->cred
);
428 msg
.rpc_argp
= &data
->args
;
429 msg
.rpc_resp
= &data
->res
;
430 msg
.rpc_cred
= data
->cred
;
432 /* set up nfs_renamedata */
433 data
->old_dir
= old_dir
;
435 data
->new_dir
= new_dir
;
437 data
->old_dentry
= dget(old_dentry
);
438 data
->new_dentry
= dget(new_dentry
);
439 nfs_fattr_init(&data
->old_fattr
);
440 nfs_fattr_init(&data
->new_fattr
);
442 /* set up nfs_renameargs */
443 data
->args
.old_dir
= NFS_FH(old_dir
);
444 data
->args
.old_name
= &old_dentry
->d_name
;
445 data
->args
.new_dir
= NFS_FH(new_dir
);
446 data
->args
.new_name
= &new_dentry
->d_name
;
448 /* set up nfs_renameres */
449 data
->res
.old_fattr
= &data
->old_fattr
;
450 data
->res
.new_fattr
= &data
->new_fattr
;
452 nfs_sb_active(old_dir
->i_sb
);
454 NFS_PROTO(data
->old_dir
)->rename_setup(&msg
, old_dir
);
456 return rpc_run_task(&task_setup_data
);
459 #define SILLYNAME_PREFIX ".nfs"
460 #define SILLYNAME_PREFIX_LEN ((unsigned)sizeof(SILLYNAME_PREFIX) - 1)
461 #define SILLYNAME_FILEID_LEN ((unsigned)sizeof(u64) << 1)
462 #define SILLYNAME_COUNTER_LEN ((unsigned)sizeof(unsigned int) << 1)
463 #define SILLYNAME_LEN (SILLYNAME_PREFIX_LEN + \
464 SILLYNAME_FILEID_LEN + \
465 SILLYNAME_COUNTER_LEN)
468 * nfs_sillyrename - Perform a silly-rename of a dentry
469 * @dir: inode of directory that contains dentry
470 * @dentry: dentry to be sillyrenamed
472 * NFSv2/3 is stateless and the server doesn't know when the client is
473 * holding a file open. To prevent application problems when a file is
474 * unlinked while it's still open, the client performs a "silly-rename".
475 * That is, it renames the file to a hidden file in the same directory,
476 * and only performs the unlink once the last reference to it is put.
478 * The final cleanup is done during dentry_iput.
480 * (Note: NFSv4 is stateful, and has opens, so in theory an NFSv4 server
481 * could take responsibility for keeping open files referenced. The server
482 * would also need to ensure that opened-but-deleted files were kept over
483 * reboots. However, we may not assume a server does so. (RFC 5661
484 * does provide an OPEN4_RESULT_PRESERVE_UNLINKED flag that a server can
485 * use to advertise that it does this; some day we may take advantage of
489 nfs_sillyrename(struct inode
*dir
, struct dentry
*dentry
)
491 static unsigned int sillycounter
;
492 unsigned char silly
[SILLYNAME_LEN
+ 1];
493 unsigned long long fileid
;
494 struct dentry
*sdentry
;
495 struct rpc_task
*task
;
498 dfprintk(VFS
, "NFS: silly-rename(%s/%s, ct=%d)\n",
499 dentry
->d_parent
->d_name
.name
, dentry
->d_name
.name
,
501 nfs_inc_stats(dir
, NFSIOS_SILLYRENAME
);
504 * We don't allow a dentry to be silly-renamed twice.
507 if (dentry
->d_flags
& DCACHE_NFSFS_RENAMED
)
510 fileid
= NFS_FILEID(dentry
->d_inode
);
512 /* Return delegation in anticipation of the rename */
513 NFS_PROTO(dentry
->d_inode
)->return_delegation(dentry
->d_inode
);
520 slen
= scnprintf(silly
, sizeof(silly
),
521 SILLYNAME_PREFIX
"%0*llx%0*x",
522 SILLYNAME_FILEID_LEN
, fileid
,
523 SILLYNAME_COUNTER_LEN
, sillycounter
);
525 dfprintk(VFS
, "NFS: trying to rename %s to %s\n",
526 dentry
->d_name
.name
, silly
);
528 sdentry
= lookup_one_len(silly
, dentry
->d_parent
, slen
);
530 * N.B. Better to return EBUSY here ... it could be
531 * dangerous to delete the file while it's in use.
535 } while (sdentry
->d_inode
!= NULL
); /* need negative lookup */
537 /* queue unlink first. Can't do this from rpc_release as it
538 * has to allocate memory
540 error
= nfs_async_unlink(dir
, dentry
);
544 /* populate unlinkdata with the right dname */
545 error
= nfs_copy_dname(sdentry
,
546 (struct nfs_unlinkdata
*)dentry
->d_fsdata
);
548 nfs_cancel_async_unlink(dentry
);
552 /* run the rename task, undo unlink if it fails */
553 task
= nfs_async_rename(dir
, dir
, dentry
, sdentry
);
556 nfs_cancel_async_unlink(dentry
);
560 /* wait for the RPC task to complete, unless a SIGKILL intervenes */
561 error
= rpc_wait_for_completion_task(task
);
563 error
= task
->tk_status
;
566 /* The rename succeeded */
567 nfs_set_verifier(dentry
, nfs_save_change_attribute(dir
));
568 d_move(dentry
, sdentry
);
571 /* The result of the rename is unknown. Play it safe by
572 * forcing a new lookup */