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"
24 * nfs_free_unlinkdata - release data from a sillydelete operation.
25 * @data: pointer to unlink structure.
28 nfs_free_unlinkdata(struct nfs_unlinkdata *data)
31 put_rpccred(data->cred);
32 kfree(data->args.name.name);
36 #define NAME_ALLOC_LEN(len) ((len+16) & ~15)
38 * nfs_copy_dname - copy dentry name to data structure
39 * @dentry: pointer to dentry
40 * @data: nfs_unlinkdata
42 static int nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
45 int len = dentry->d_name.len;
47 str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
50 data->args.name.len = len;
51 data->args.name.name = str;
55 static void nfs_free_dname(struct nfs_unlinkdata *data)
57 kfree(data->args.name.name);
58 data->args.name.name = NULL;
59 data->args.name.len = 0;
62 static void nfs_dec_sillycount(struct inode *dir)
64 struct nfs_inode *nfsi = NFS_I(dir);
65 if (atomic_dec_return(&nfsi->silly_count) == 1)
66 wake_up(&nfsi->waitqueue);
70 * nfs_async_unlink_done - Sillydelete post-processing
71 * @task: rpc_task of the sillydelete
73 * Do the directory attribute update.
75 static void nfs_async_unlink_done(struct rpc_task *task, void *calldata)
77 struct nfs_unlinkdata *data = calldata;
78 struct inode *dir = data->dir;
80 if (!NFS_PROTO(dir)->unlink_done(task, dir))
81 rpc_restart_call_prepare(task);
85 * nfs_async_unlink_release - Release the sillydelete data.
86 * @task: rpc_task of the sillydelete
88 * We need to call nfs_put_unlinkdata as a 'tk_release' task since the
89 * rpc_task would be freed too.
91 static void nfs_async_unlink_release(void *calldata)
93 struct nfs_unlinkdata *data = calldata;
94 struct super_block *sb = data->dir->i_sb;
96 nfs_dec_sillycount(data->dir);
97 nfs_free_unlinkdata(data);
101 static void nfs_unlink_prepare(struct rpc_task *task, void *calldata)
103 struct nfs_unlinkdata *data = calldata;
104 NFS_PROTO(data->dir)->unlink_rpc_prepare(task, data);
107 static 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,
113 static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct nfs_unlinkdata *data)
115 struct rpc_message msg = {
116 .rpc_argp = &data->args,
117 .rpc_resp = &data->res,
118 .rpc_cred = data->cred,
120 struct rpc_task_setup task_setup_data = {
122 .callback_ops = &nfs_unlink_ops,
123 .callback_data = data,
124 .workqueue = nfsiod_workqueue,
125 .flags = RPC_TASK_ASYNC,
127 struct rpc_task *task;
128 struct dentry *alias;
130 alias = d_lookup(parent, &data->args.name);
133 void *devname_garbage = NULL;
136 * Hey, we raced with lookup... See if we need to transfer
137 * the sillyrename information to the aliased dentry.
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;
150 spin_unlock(&alias->d_lock);
151 nfs_dec_sillycount(dir);
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
158 kfree(devname_garbage);
161 data->dir = igrab(dir);
163 nfs_dec_sillycount(dir);
166 nfs_sb_active(dir->i_sb);
167 data->args.fh = NFS_FH(dir);
168 nfs_fattr_init(data->res.dir_attr);
170 NFS_PROTO(dir)->unlink_setup(&msg, dir);
172 task_setup_data.rpc_client = NFS_CLIENT(dir);
173 task = rpc_run_task(&task_setup_data);
175 rpc_put_task_async(task);
179 static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
181 struct dentry *parent;
186 parent = dget_parent(dentry);
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);
199 spin_unlock(&dir->i_lock);
200 ret = nfs_do_call_unlink(parent, dir, data);
207 void nfs_block_sillyrename(struct dentry *dentry)
209 struct nfs_inode *nfsi = NFS_I(dentry->d_inode);
211 wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1);
214 void nfs_unblock_sillyrename(struct dentry *dentry)
216 struct inode *dir = dentry->d_inode;
217 struct nfs_inode *nfsi = NFS_I(dir);
218 struct nfs_unlinkdata *data;
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))
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);
232 spin_unlock(&dir->i_lock);
236 * nfs_async_unlink - asynchronous unlinking of a file
237 * @dir: parent directory of dentry
238 * @dentry: dentry to unlink
241 nfs_async_unlink(struct inode *dir, struct dentry *dentry)
243 struct nfs_unlinkdata *data;
244 int status = -ENOMEM;
245 void *devname_garbage = NULL;
247 data = kzalloc(sizeof(*data), GFP_KERNEL);
251 data->cred = rpc_lookup_cred();
252 if (IS_ERR(data->cred)) {
253 status = PTR_ERR(data->cred);
256 data->res.dir_attr = &data->dir_attr;
259 spin_lock(&dentry->d_lock);
260 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
262 dentry->d_flags |= DCACHE_NFSFS_RENAMED;
263 devname_garbage = dentry->d_fsdata;
264 dentry->d_fsdata = data;
265 spin_unlock(&dentry->d_lock);
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
271 kfree(devname_garbage);
274 spin_unlock(&dentry->d_lock);
275 put_rpccred(data->cred);
283 * nfs_complete_unlink - Initialize completion of the sillydelete
284 * @dentry: dentry to delete
287 * Since we're most likely to be called by dentry_iput(), we
288 * only use the dentry to find the sillydelete. We then copy the name
292 nfs_complete_unlink(struct dentry *dentry, struct inode *inode)
294 struct nfs_unlinkdata *data = NULL;
296 spin_lock(&dentry->d_lock);
297 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
298 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
299 data = dentry->d_fsdata;
300 dentry->d_fsdata = NULL;
302 spin_unlock(&dentry->d_lock);
304 if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data)))
305 nfs_free_unlinkdata(data);
308 /* Cancel a queued async unlink. Called when a sillyrename run fails. */
310 nfs_cancel_async_unlink(struct dentry *dentry)
312 spin_lock(&dentry->d_lock);
313 if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
314 struct nfs_unlinkdata *data = dentry->d_fsdata;
316 dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
317 dentry->d_fsdata = NULL;
318 spin_unlock(&dentry->d_lock);
319 nfs_free_unlinkdata(data);
322 spin_unlock(&dentry->d_lock);
326 * nfs_async_rename_done - Sillyrename post-processing
327 * @task: rpc_task of the sillyrename
328 * @calldata: nfs_renamedata for the sillyrename
330 * Do the directory attribute updates and the d_move
332 static void nfs_async_rename_done(struct rpc_task *task, void *calldata)
334 struct nfs_renamedata *data = calldata;
335 struct inode *old_dir = data->old_dir;
336 struct inode *new_dir = data->new_dir;
337 struct dentry *old_dentry = data->old_dentry;
338 struct dentry *new_dentry = data->new_dentry;
340 if (!NFS_PROTO(old_dir)->rename_done(task, old_dir, new_dir)) {
341 rpc_restart_call_prepare(task);
345 if (task->tk_status != 0) {
346 nfs_cancel_async_unlink(old_dentry);
355 * nfs_async_rename_release - Release the sillyrename data.
356 * @calldata: the struct nfs_renamedata to be released
358 static void nfs_async_rename_release(void *calldata)
360 struct nfs_renamedata *data = calldata;
361 struct super_block *sb = data->old_dir->i_sb;
363 if (data->old_dentry->d_inode)
364 nfs_mark_for_revalidate(data->old_dentry->d_inode);
366 dput(data->old_dentry);
367 dput(data->new_dentry);
371 put_rpccred(data->cred);
375 static void nfs_rename_prepare(struct rpc_task *task, void *calldata)
377 struct nfs_renamedata *data = calldata;
378 NFS_PROTO(data->old_dir)->rename_rpc_prepare(task, data);
381 static const struct rpc_call_ops nfs_rename_ops = {
382 .rpc_call_done = nfs_async_rename_done,
383 .rpc_release = nfs_async_rename_release,
384 .rpc_call_prepare = nfs_rename_prepare,
388 * nfs_async_rename - perform an asynchronous rename operation
389 * @old_dir: directory that currently holds the dentry to be renamed
390 * @new_dir: target directory for the rename
391 * @old_dentry: original dentry to be renamed
392 * @new_dentry: dentry to which the old_dentry should be renamed
394 * It's expected that valid references to the dentries and inodes are held
396 static struct rpc_task *
397 nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
398 struct dentry *old_dentry, struct dentry *new_dentry)
400 struct nfs_renamedata *data;
401 struct rpc_message msg = { };
402 struct rpc_task_setup task_setup_data = {
404 .callback_ops = &nfs_rename_ops,
405 .workqueue = nfsiod_workqueue,
406 .rpc_client = NFS_CLIENT(old_dir),
407 .flags = RPC_TASK_ASYNC,
410 data = kzalloc(sizeof(*data), GFP_KERNEL);
412 return ERR_PTR(-ENOMEM);
413 task_setup_data.callback_data = data;
415 data->cred = rpc_lookup_cred();
416 if (IS_ERR(data->cred)) {
417 struct rpc_task *task = ERR_CAST(data->cred);
422 msg.rpc_argp = &data->args;
423 msg.rpc_resp = &data->res;
424 msg.rpc_cred = data->cred;
426 /* set up nfs_renamedata */
427 data->old_dir = old_dir;
429 data->new_dir = new_dir;
431 data->old_dentry = dget(old_dentry);
432 data->new_dentry = dget(new_dentry);
433 nfs_fattr_init(&data->old_fattr);
434 nfs_fattr_init(&data->new_fattr);
436 /* set up nfs_renameargs */
437 data->args.old_dir = NFS_FH(old_dir);
438 data->args.old_name = &old_dentry->d_name;
439 data->args.new_dir = NFS_FH(new_dir);
440 data->args.new_name = &new_dentry->d_name;
442 /* set up nfs_renameres */
443 data->res.old_fattr = &data->old_fattr;
444 data->res.new_fattr = &data->new_fattr;
446 nfs_sb_active(old_dir->i_sb);
448 NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dir);
450 return rpc_run_task(&task_setup_data);
454 * nfs_sillyrename - Perform a silly-rename of a dentry
455 * @dir: inode of directory that contains dentry
456 * @dentry: dentry to be sillyrenamed
458 * NFSv2/3 is stateless and the server doesn't know when the client is
459 * holding a file open. To prevent application problems when a file is
460 * unlinked while it's still open, the client performs a "silly-rename".
461 * That is, it renames the file to a hidden file in the same directory,
462 * and only performs the unlink once the last reference to it is put.
464 * The final cleanup is done during dentry_iput.
466 * (Note: NFSv4 is stateful, and has opens, so in theory an NFSv4 server
467 * could take responsibility for keeping open files referenced. The server
468 * would also need to ensure that opened-but-deleted files were kept over
469 * reboots. However, we may not assume a server does so. (RFC 5661
470 * does provide an OPEN4_RESULT_PRESERVE_UNLINKED flag that a server can
471 * use to advertise that it does this; some day we may take advantage of
475 nfs_sillyrename(struct inode *dir, struct dentry *dentry)
477 static unsigned int sillycounter;
478 const int fileidsize = sizeof(NFS_FILEID(dentry->d_inode))*2;
479 const int countersize = sizeof(sillycounter)*2;
480 const int slen = sizeof(".nfs")+fileidsize+countersize-1;
482 struct dentry *sdentry;
483 struct rpc_task *task;
486 dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n",
487 dentry->d_parent->d_name.name, dentry->d_name.name,
489 nfs_inc_stats(dir, NFSIOS_SILLYRENAME);
492 * We don't allow a dentry to be silly-renamed twice.
495 if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
498 sprintf(silly, ".nfs%*.*Lx",
499 fileidsize, fileidsize,
500 (unsigned long long)NFS_FILEID(dentry->d_inode));
502 /* Return delegation in anticipation of the rename */
503 NFS_PROTO(dentry->d_inode)->return_delegation(dentry->d_inode);
507 char *suffix = silly + slen - countersize;
511 sprintf(suffix, "%*.*x", countersize, countersize, sillycounter);
513 dfprintk(VFS, "NFS: trying to rename %s to %s\n",
514 dentry->d_name.name, silly);
516 sdentry = lookup_one_len(silly, dentry->d_parent, slen);
518 * N.B. Better to return EBUSY here ... it could be
519 * dangerous to delete the file while it's in use.
523 } while (sdentry->d_inode != NULL); /* need negative lookup */
525 /* queue unlink first. Can't do this from rpc_release as it
526 * has to allocate memory
528 error = nfs_async_unlink(dir, dentry);
532 /* populate unlinkdata with the right dname */
533 error = nfs_copy_dname(sdentry,
534 (struct nfs_unlinkdata *)dentry->d_fsdata);
536 nfs_cancel_async_unlink(dentry);
540 /* run the rename task, undo unlink if it fails */
541 task = nfs_async_rename(dir, dir, dentry, sdentry);
544 nfs_cancel_async_unlink(dentry);
548 /* wait for the RPC task to complete, unless a SIGKILL intervenes */
549 error = rpc_wait_for_completion_task(task);
551 error = task->tk_status;