1 // SPDX-License-Identifier: GPL-2.0
3 * linux/fs/nfs/unlink.c
5 * nfs sillydelete handling
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>
23 #include "delegation.h"
28 * nfs_free_unlinkdata - release data from a sillydelete operation.
29 * @data: pointer to unlink structure.
32 nfs_free_unlinkdata(struct nfs_unlinkdata *data)
35 kfree(data->args.name.name);
40 * nfs_async_unlink_done - Sillydelete post-processing
41 * @task: rpc_task of the sillydelete
43 * Do the directory attribute update.
45 static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
47 struct nfs_unlinkdata *data = calldata;
48 struct inode *dir = d_inode(data->dentry->d_parent);
50 trace_nfs_sillyrename_unlink(data, task->tk_status);
51 if (!NFS_PROTO(dir)->unlink_done(task, dir))
52 rpc_restart_call_prepare(task);
56 * nfs_async_unlink_release - Release the sillydelete data.
57 * @task: rpc_task of the sillydelete
59 * We need to call nfs_put_unlinkdata as a 'tk_release' task since the
60 * rpc_task would be freed too.
62 static void nfs_async_unlink_release(void *calldata)
64 struct nfs_unlinkdata *data = calldata;
65 struct dentry *dentry = data->dentry;
66 struct super_block *sb = dentry->d_sb;
68 up_read_non_owner(&NFS_I(d_inode(dentry->d_parent))->rmdir_sem);
69 d_lookup_done(dentry);
70 nfs_free_unlinkdata(data);
75 static void nfs_unlink_prepare(struct rpc_task *task, void *calldata)
77 struct nfs_unlinkdata *data = calldata;
78 struct inode *dir = d_inode(data->dentry->d_parent);
79 NFS_PROTO(dir)->unlink_rpc_prepare(task, data);
82 static const struct rpc_call_ops nfs_unlink_ops = {
83 .rpc_call_done = nfs_async_unlink_done,
84 .rpc_release = nfs_async_unlink_release,
85 .rpc_call_prepare = nfs_unlink_prepare,
88 static void nfs_do_call_unlink(struct inode *inode, struct nfs_unlinkdata *data)
90 struct rpc_message msg = {
91 .rpc_argp = &data->args,
92 .rpc_resp = &data->res,
93 .rpc_cred = data->cred,
95 struct rpc_task_setup task_setup_data = {
97 .callback_ops = &nfs_unlink_ops,
98 .callback_data = data,
99 .workqueue = nfsiod_workqueue,
100 .flags = RPC_TASK_ASYNC,
102 struct rpc_task *task;
103 struct inode *dir = d_inode(data->dentry->d_parent);
104 nfs_sb_active(dir->i_sb);
105 data->args.fh = NFS_FH(dir);
106 nfs_fattr_init(data->res.dir_attr);
108 NFS_PROTO(dir)->unlink_setup(&msg, data->dentry, inode);
110 task_setup_data.rpc_client = NFS_CLIENT(dir);
111 task = rpc_run_task(&task_setup_data);
113 rpc_put_task_async(task);
116 static int nfs_call_unlink(struct dentry *dentry, struct inode *inode, struct nfs_unlinkdata *data)
118 struct inode *dir = d_inode(dentry->d_parent);
119 struct dentry *alias;
121 down_read_non_owner(&NFS_I(dir)->rmdir_sem);
122 alias = d_alloc_parallel(dentry->d_parent, &data->args.name, &data->wq);
124 up_read_non_owner(&NFS_I(dir)->rmdir_sem);
127 if (!d_in_lookup(alias)) {
129 void *devname_garbage = NULL;
132 * Hey, we raced with lookup... See if we need to transfer
133 * the sillyrename information to the aliased dentry.
135 spin_lock(&alias->d_lock);
136 if (d_really_is_positive(alias) &&
137 !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
138 devname_garbage = alias->d_fsdata;
139 alias->d_fsdata = data;
140 alias->d_flags |= DCACHE_NFSFS_RENAMED;
144 spin_unlock(&alias->d_lock);
146 up_read_non_owner(&NFS_I(dir)->rmdir_sem);
148 * If we'd displaced old cached devname, free it. At that
149 * point dentry is definitely not a root, so we won't need
152 kfree(devname_garbage);
155 data->dentry = alias;
156 nfs_do_call_unlink(inode, data);
161 * nfs_async_unlink - asynchronous unlinking of a file
162 * @dir: parent directory of dentry
163 * @dentry: dentry to unlink
166 nfs_async_unlink(struct dentry *dentry, const struct qstr *name)
168 struct nfs_unlinkdata *data;
169 int status = -ENOMEM;
170 void *devname_garbage = NULL;
172 data = kzalloc(sizeof(*data), GFP_KERNEL);
175 data->args.name.name = kstrdup(name->name, GFP_KERNEL);
176 if (!data->args.name.name)
178 data->args.name.len = name->len;
180 data->cred = get_current_cred();
181 data->res.dir_attr = &data->dir_attr;
182 init_waitqueue_head(&data->wq);
185 spin_lock(&dentry->d_lock);
186 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
188 dentry->d_flags |= DCACHE_NFSFS_RENAMED;
189 devname_garbage = dentry->d_fsdata;
190 dentry->d_fsdata = data;
191 spin_unlock(&dentry->d_lock);
193 * If we'd displaced old cached devname, free it. At that
194 * point dentry is definitely not a root, so we won't need
197 kfree(devname_garbage);
200 spin_unlock(&dentry->d_lock);
201 put_cred(data->cred);
202 kfree(data->args.name.name);
210 * nfs_complete_unlink - Initialize completion of the sillydelete
211 * @dentry: dentry to delete
214 * Since we're most likely to be called by dentry_iput(), we
215 * only use the dentry to find the sillydelete. We then copy the name
219 nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
221 struct nfs_unlinkdata *data;
223 spin_lock(&dentry->d_lock);
224 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
225 data = dentry->d_fsdata;
226 dentry->d_fsdata = NULL;
227 spin_unlock(&dentry->d_lock);
229 if (NFS_STALE(inode) || !nfs_call_unlink(dentry, inode, data))
230 nfs_free_unlinkdata(data);
233 /* Cancel a queued async unlink. Called when a sillyrename run fails. */
235 nfs_cancel_async_unlink(struct dentry *dentry)
237 spin_lock(&dentry->d_lock);
238 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
239 struct nfs_unlinkdata *data = dentry->d_fsdata;
241 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
242 dentry->d_fsdata = NULL;
243 spin_unlock(&dentry->d_lock);
244 nfs_free_unlinkdata(data);
247 spin_unlock(&dentry->d_lock);
251 * nfs_async_rename_done - Sillyrename post-processing
252 * @task: rpc_task of the sillyrename
253 * @calldata: nfs_renamedata for the sillyrename
255 * Do the directory attribute updates and the d_move
257 static void nfs_async_rename_done(struct rpc_task *task, void *calldata)
259 struct nfs_renamedata *data = calldata;
260 struct inode *old_dir = data->old_dir;
261 struct inode *new_dir = data->new_dir;
262 struct dentry *old_dentry = data->old_dentry;
264 trace_nfs_sillyrename_rename(old_dir, old_dentry,
265 new_dir, data->new_dentry, task->tk_status);
266 if (!NFS_PROTO(old_dir)->rename_done(task, old_dir, new_dir)) {
267 rpc_restart_call_prepare(task);
272 data->complete(task, data);
276 * nfs_async_rename_release - Release the sillyrename data.
277 * @calldata: the struct nfs_renamedata to be released
279 static void nfs_async_rename_release(void *calldata)
281 struct nfs_renamedata *data = calldata;
282 struct super_block *sb = data->old_dir->i_sb;
284 if (d_really_is_positive(data->old_dentry))
285 nfs_mark_for_revalidate(d_inode(data->old_dentry));
287 /* The result of the rename is unknown. Play it safe by
288 * forcing a new lookup */
289 if (data->cancelled) {
290 spin_lock(&data->old_dir->i_lock);
291 nfs_force_lookup_revalidate(data->old_dir);
292 spin_unlock(&data->old_dir->i_lock);
293 if (data->new_dir != data->old_dir) {
294 spin_lock(&data->new_dir->i_lock);
295 nfs_force_lookup_revalidate(data->new_dir);
296 spin_unlock(&data->new_dir->i_lock);
300 dput(data->old_dentry);
301 dput(data->new_dentry);
305 put_cred(data->cred);
309 static void nfs_rename_prepare(struct rpc_task *task, void *calldata)
311 struct nfs_renamedata *data = calldata;
312 NFS_PROTO(data->old_dir)->rename_rpc_prepare(task, data);
315 static const struct rpc_call_ops nfs_rename_ops = {
316 .rpc_call_done = nfs_async_rename_done,
317 .rpc_release = nfs_async_rename_release,
318 .rpc_call_prepare = nfs_rename_prepare,
322 * nfs_async_rename - perform an asynchronous rename operation
323 * @old_dir: directory that currently holds the dentry to be renamed
324 * @new_dir: target directory for the rename
325 * @old_dentry: original dentry to be renamed
326 * @new_dentry: dentry to which the old_dentry should be renamed
328 * It's expected that valid references to the dentries and inodes are held
331 nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
332 struct dentry *old_dentry, struct dentry *new_dentry,
333 void (*complete)(struct rpc_task *, struct nfs_renamedata *))
335 struct nfs_renamedata *data;
336 struct rpc_message msg = { };
337 struct rpc_task_setup task_setup_data = {
339 .callback_ops = &nfs_rename_ops,
340 .workqueue = nfsiod_workqueue,
341 .rpc_client = NFS_CLIENT(old_dir),
342 .flags = RPC_TASK_ASYNC,
345 data = kzalloc(sizeof(*data), GFP_KERNEL);
347 return ERR_PTR(-ENOMEM);
348 task_setup_data.callback_data = data;
350 data->cred = get_current_cred();
352 msg.rpc_argp = &data->args;
353 msg.rpc_resp = &data->res;
354 msg.rpc_cred = data->cred;
356 /* set up nfs_renamedata */
357 data->old_dir = old_dir;
359 data->new_dir = new_dir;
361 data->old_dentry = dget(old_dentry);
362 data->new_dentry = dget(new_dentry);
363 nfs_fattr_init(&data->old_fattr);
364 nfs_fattr_init(&data->new_fattr);
365 data->complete = complete;
367 /* set up nfs_renameargs */
368 data->args.old_dir = NFS_FH(old_dir);
369 data->args.old_name = &old_dentry->d_name;
370 data->args.new_dir = NFS_FH(new_dir);
371 data->args.new_name = &new_dentry->d_name;
373 /* set up nfs_renameres */
374 data->res.old_fattr = &data->old_fattr;
375 data->res.new_fattr = &data->new_fattr;
377 nfs_sb_active(old_dir->i_sb);
379 NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dentry, new_dentry);
381 return rpc_run_task(&task_setup_data);
385 * Perform tasks needed when a sillyrename is done such as cancelling the
386 * queued async unlink if it failed.
389 nfs_complete_sillyrename(struct rpc_task *task, struct nfs_renamedata *data)
391 struct dentry *dentry = data->old_dentry;
393 if (task->tk_status != 0) {
394 nfs_cancel_async_unlink(dentry);
399 * vfs_unlink and the like do not issue this when a file is
400 * sillyrenamed, so do it here.
402 fsnotify_nameremove(dentry, 0);
405 #define SILLYNAME_PREFIX ".nfs"
406 #define SILLYNAME_PREFIX_LEN ((unsigned)sizeof(SILLYNAME_PREFIX) - 1)
407 #define SILLYNAME_FILEID_LEN ((unsigned)sizeof(u64) << 1)
408 #define SILLYNAME_COUNTER_LEN ((unsigned)sizeof(unsigned int) << 1)
409 #define SILLYNAME_LEN (SILLYNAME_PREFIX_LEN + \
410 SILLYNAME_FILEID_LEN + \
411 SILLYNAME_COUNTER_LEN)
414 * nfs_sillyrename - Perform a silly-rename of a dentry
415 * @dir: inode of directory that contains dentry
416 * @dentry: dentry to be sillyrenamed
418 * NFSv2/3 is stateless and the server doesn't know when the client is
419 * holding a file open. To prevent application problems when a file is
420 * unlinked while it's still open, the client performs a "silly-rename".
421 * That is, it renames the file to a hidden file in the same directory,
422 * and only performs the unlink once the last reference to it is put.
424 * The final cleanup is done during dentry_iput.
426 * (Note: NFSv4 is stateful, and has opens, so in theory an NFSv4 server
427 * could take responsibility for keeping open files referenced. The server
428 * would also need to ensure that opened-but-deleted files were kept over
429 * reboots. However, we may not assume a server does so. (RFC 5661
430 * does provide an OPEN4_RESULT_PRESERVE_UNLINKED flag that a server can
431 * use to advertise that it does this; some day we may take advantage of
435 nfs_sillyrename(struct inode *dir, struct dentry *dentry)
437 static unsigned int sillycounter;
438 unsigned char silly[SILLYNAME_LEN + 1];
439 unsigned long long fileid;
440 struct dentry *sdentry;
441 struct inode *inode = d_inode(dentry);
442 struct rpc_task *task;
445 dfprintk(VFS, "NFS: silly-rename(%pd2, ct=%d)\n",
446 dentry, d_count(dentry));
447 nfs_inc_stats(dir, NFSIOS_SILLYRENAME);
450 * We don't allow a dentry to be silly-renamed twice.
452 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
455 fileid = NFS_FILEID(d_inode(dentry));
462 slen = scnprintf(silly, sizeof(silly),
463 SILLYNAME_PREFIX "%0*llx%0*x",
464 SILLYNAME_FILEID_LEN, fileid,
465 SILLYNAME_COUNTER_LEN, sillycounter);
467 dfprintk(VFS, "NFS: trying to rename %pd to %s\n",
470 sdentry = lookup_one_len(silly, dentry->d_parent, slen);
472 * N.B. Better to return EBUSY here ... it could be
473 * dangerous to delete the file while it's in use.
477 } while (d_inode(sdentry) != NULL); /* need negative lookup */
481 /* queue unlink first. Can't do this from rpc_release as it
482 * has to allocate memory
484 error = nfs_async_unlink(dentry, &sdentry->d_name);
488 /* run the rename task, undo unlink if it fails */
489 task = nfs_async_rename(dir, dir, dentry, sdentry,
490 nfs_complete_sillyrename);
493 nfs_cancel_async_unlink(dentry);
497 /* wait for the RPC task to complete, unless a SIGKILL intervenes */
498 error = rpc_wait_for_completion_task(task);
500 error = task->tk_status;
503 /* The rename succeeded */
504 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
505 spin_lock(&inode->i_lock);
506 NFS_I(inode)->attr_gencount = nfs_inc_attr_generation_counter();
507 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_CHANGE
508 | NFS_INO_INVALID_CTIME
509 | NFS_INO_REVAL_FORCED;
510 spin_unlock(&inode->i_lock);
511 d_move(dentry, sdentry);
514 /* The result of the rename is unknown. Play it safe by
515 * forcing a new lookup */