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-rw-r--r--fs/kernfs/dir.c1073
1 files changed, 1073 insertions, 0 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
new file mode 100644
index 000000000000..5104cf5d25c5
--- /dev/null
+++ b/fs/kernfs/dir.c
@@ -0,0 +1,1073 @@
1/*
2 * fs/kernfs/dir.c - kernfs directory implementation
3 *
4 * Copyright (c) 2001-3 Patrick Mochel
5 * Copyright (c) 2007 SUSE Linux Products GmbH
6 * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
7 *
8 * This file is released under the GPLv2.
9 */
10
11#include <linux/fs.h>
12#include <linux/namei.h>
13#include <linux/idr.h>
14#include <linux/slab.h>
15#include <linux/security.h>
16#include <linux/hash.h>
17
18#include "kernfs-internal.h"
19
20DEFINE_MUTEX(kernfs_mutex);
21
22#define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
23
24/**
25 * kernfs_name_hash
26 * @name: Null terminated string to hash
27 * @ns: Namespace tag to hash
28 *
29 * Returns 31 bit hash of ns + name (so it fits in an off_t )
30 */
31static unsigned int kernfs_name_hash(const char *name, const void *ns)
32{
33 unsigned long hash = init_name_hash();
34 unsigned int len = strlen(name);
35 while (len--)
36 hash = partial_name_hash(*name++, hash);
37 hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31));
38 hash &= 0x7fffffffU;
39 /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
40 if (hash < 1)
41 hash += 2;
42 if (hash >= INT_MAX)
43 hash = INT_MAX - 1;
44 return hash;
45}
46
47static int kernfs_name_compare(unsigned int hash, const char *name,
48 const void *ns, const struct kernfs_node *kn)
49{
50 if (hash != kn->hash)
51 return hash - kn->hash;
52 if (ns != kn->ns)
53 return ns - kn->ns;
54 return strcmp(name, kn->name);
55}
56
57static int kernfs_sd_compare(const struct kernfs_node *left,
58 const struct kernfs_node *right)
59{
60 return kernfs_name_compare(left->hash, left->name, left->ns, right);
61}
62
63/**
64 * kernfs_link_sibling - link kernfs_node into sibling rbtree
65 * @kn: kernfs_node of interest
66 *
67 * Link @kn into its sibling rbtree which starts from
68 * @kn->parent->dir.children.
69 *
70 * Locking:
71 * mutex_lock(kernfs_mutex)
72 *
73 * RETURNS:
74 * 0 on susccess -EEXIST on failure.
75 */
76static int kernfs_link_sibling(struct kernfs_node *kn)
77{
78 struct rb_node **node = &kn->parent->dir.children.rb_node;
79 struct rb_node *parent = NULL;
80
81 if (kernfs_type(kn) == KERNFS_DIR)
82 kn->parent->dir.subdirs++;
83
84 while (*node) {
85 struct kernfs_node *pos;
86 int result;
87
88 pos = rb_to_kn(*node);
89 parent = *node;
90 result = kernfs_sd_compare(kn, pos);
91 if (result < 0)
92 node = &pos->rb.rb_left;
93 else if (result > 0)
94 node = &pos->rb.rb_right;
95 else
96 return -EEXIST;
97 }
98 /* add new node and rebalance the tree */
99 rb_link_node(&kn->rb, parent, node);
100 rb_insert_color(&kn->rb, &kn->parent->dir.children);
101 return 0;
102}
103
104/**
105 * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree
106 * @kn: kernfs_node of interest
107 *
108 * Unlink @kn from its sibling rbtree which starts from
109 * kn->parent->dir.children.
110 *
111 * Locking:
112 * mutex_lock(kernfs_mutex)
113 */
114static void kernfs_unlink_sibling(struct kernfs_node *kn)
115{
116 if (kernfs_type(kn) == KERNFS_DIR)
117 kn->parent->dir.subdirs--;
118
119 rb_erase(&kn->rb, &kn->parent->dir.children);
120}
121
122/**
123 * kernfs_get_active - get an active reference to kernfs_node
124 * @kn: kernfs_node to get an active reference to
125 *
126 * Get an active reference of @kn. This function is noop if @kn
127 * is NULL.
128 *
129 * RETURNS:
130 * Pointer to @kn on success, NULL on failure.
131 */
132struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
133{
134 if (unlikely(!kn))
135 return NULL;
136
137 if (!atomic_inc_unless_negative(&kn->active))
138 return NULL;
139
140 if (kn->flags & KERNFS_LOCKDEP)
141 rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
142 return kn;
143}
144
145/**
146 * kernfs_put_active - put an active reference to kernfs_node
147 * @kn: kernfs_node to put an active reference to
148 *
149 * Put an active reference to @kn. This function is noop if @kn
150 * is NULL.
151 */
152void kernfs_put_active(struct kernfs_node *kn)
153{
154 int v;
155
156 if (unlikely(!kn))
157 return;
158
159 if (kn->flags & KERNFS_LOCKDEP)
160 rwsem_release(&kn->dep_map, 1, _RET_IP_);
161 v = atomic_dec_return(&kn->active);
162 if (likely(v != KN_DEACTIVATED_BIAS))
163 return;
164
165 /*
166 * atomic_dec_return() is a mb(), we'll always see the updated
167 * kn->u.completion.
168 */
169 complete(kn->u.completion);
170}
171
172/**
173 * kernfs_deactivate - deactivate kernfs_node
174 * @kn: kernfs_node to deactivate
175 *
176 * Deny new active references and drain existing ones.
177 */
178static void kernfs_deactivate(struct kernfs_node *kn)
179{
180 DECLARE_COMPLETION_ONSTACK(wait);
181 int v;
182
183 BUG_ON(!(kn->flags & KERNFS_REMOVED));
184
185 if (!(kernfs_type(kn) & KERNFS_ACTIVE_REF))
186 return;
187
188 kn->u.completion = (void *)&wait;
189
190 rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
191 /* atomic_add_return() is a mb(), put_active() will always see
192 * the updated kn->u.completion.
193 */
194 v = atomic_add_return(KN_DEACTIVATED_BIAS, &kn->active);
195
196 if (v != KN_DEACTIVATED_BIAS) {
197 lock_contended(&kn->dep_map, _RET_IP_);
198 wait_for_completion(&wait);
199 }
200
201 lock_acquired(&kn->dep_map, _RET_IP_);
202 rwsem_release(&kn->dep_map, 1, _RET_IP_);
203}
204
205/**
206 * kernfs_get - get a reference count on a kernfs_node
207 * @kn: the target kernfs_node
208 */
209void kernfs_get(struct kernfs_node *kn)
210{
211 if (kn) {
212 WARN_ON(!atomic_read(&kn->count));
213 atomic_inc(&kn->count);
214 }
215}
216EXPORT_SYMBOL_GPL(kernfs_get);
217
218/**
219 * kernfs_put - put a reference count on a kernfs_node
220 * @kn: the target kernfs_node
221 *
222 * Put a reference count of @kn and destroy it if it reached zero.
223 */
224void kernfs_put(struct kernfs_node *kn)
225{
226 struct kernfs_node *parent;
227 struct kernfs_root *root;
228
229 if (!kn || !atomic_dec_and_test(&kn->count))
230 return;
231 root = kernfs_root(kn);
232 repeat:
233 /* Moving/renaming is always done while holding reference.
234 * kn->parent won't change beneath us.
235 */
236 parent = kn->parent;
237
238 WARN(!(kn->flags & KERNFS_REMOVED), "kernfs: free using entry: %s/%s\n",
239 parent ? parent->name : "", kn->name);
240
241 if (kernfs_type(kn) == KERNFS_LINK)
242 kernfs_put(kn->symlink.target_kn);
243 if (!(kn->flags & KERNFS_STATIC_NAME))
244 kfree(kn->name);
245 if (kn->iattr) {
246 if (kn->iattr->ia_secdata)
247 security_release_secctx(kn->iattr->ia_secdata,
248 kn->iattr->ia_secdata_len);
249 simple_xattrs_free(&kn->iattr->xattrs);
250 }
251 kfree(kn->iattr);
252 ida_simple_remove(&root->ino_ida, kn->ino);
253 kmem_cache_free(kernfs_node_cache, kn);
254
255 kn = parent;
256 if (kn) {
257 if (atomic_dec_and_test(&kn->count))
258 goto repeat;
259 } else {
260 /* just released the root kn, free @root too */
261 ida_destroy(&root->ino_ida);
262 kfree(root);
263 }
264}
265EXPORT_SYMBOL_GPL(kernfs_put);
266
267static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
268{
269 struct kernfs_node *kn;
270
271 if (flags & LOOKUP_RCU)
272 return -ECHILD;
273
274 /* Always perform fresh lookup for negatives */
275 if (!dentry->d_inode)
276 goto out_bad_unlocked;
277
278 kn = dentry->d_fsdata;
279 mutex_lock(&kernfs_mutex);
280
281 /* The kernfs node has been deleted */
282 if (kn->flags & KERNFS_REMOVED)
283 goto out_bad;
284
285 /* The kernfs node has been moved? */
286 if (dentry->d_parent->d_fsdata != kn->parent)
287 goto out_bad;
288
289 /* The kernfs node has been renamed */
290 if (strcmp(dentry->d_name.name, kn->name) != 0)
291 goto out_bad;
292
293 /* The kernfs node has been moved to a different namespace */
294 if (kn->parent && kernfs_ns_enabled(kn->parent) &&
295 kernfs_info(dentry->d_sb)->ns != kn->ns)
296 goto out_bad;
297
298 mutex_unlock(&kernfs_mutex);
299out_valid:
300 return 1;
301out_bad:
302 mutex_unlock(&kernfs_mutex);
303out_bad_unlocked:
304 /*
305 * @dentry doesn't match the underlying kernfs node, drop the
306 * dentry and force lookup. If we have submounts we must allow the
307 * vfs caches to lie about the state of the filesystem to prevent
308 * leaks and other nasty things, so use check_submounts_and_drop()
309 * instead of d_drop().
310 */
311 if (check_submounts_and_drop(dentry) != 0)
312 goto out_valid;
313
314 return 0;
315}
316
317static void kernfs_dop_release(struct dentry *dentry)
318{
319 kernfs_put(dentry->d_fsdata);
320}
321
322const struct dentry_operations kernfs_dops = {
323 .d_revalidate = kernfs_dop_revalidate,
324 .d_release = kernfs_dop_release,
325};
326
327static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
328 const char *name, umode_t mode,
329 unsigned flags)
330{
331 char *dup_name = NULL;
332 struct kernfs_node *kn;
333 int ret;
334
335 if (!(flags & KERNFS_STATIC_NAME)) {
336 name = dup_name = kstrdup(name, GFP_KERNEL);
337 if (!name)
338 return NULL;
339 }
340
341 kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL);
342 if (!kn)
343 goto err_out1;
344
345 ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
346 if (ret < 0)
347 goto err_out2;
348 kn->ino = ret;
349
350 atomic_set(&kn->count, 1);
351 atomic_set(&kn->active, 0);
352
353 kn->name = name;
354 kn->mode = mode;
355 kn->flags = flags | KERNFS_REMOVED;
356
357 return kn;
358
359 err_out2:
360 kmem_cache_free(kernfs_node_cache, kn);
361 err_out1:
362 kfree(dup_name);
363 return NULL;
364}
365
366struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
367 const char *name, umode_t mode,
368 unsigned flags)
369{
370 struct kernfs_node *kn;
371
372 kn = __kernfs_new_node(kernfs_root(parent), name, mode, flags);
373 if (kn) {
374 kernfs_get(parent);
375 kn->parent = parent;
376 }
377 return kn;
378}
379
380/**
381 * kernfs_addrm_start - prepare for kernfs_node add/remove
382 * @acxt: pointer to kernfs_addrm_cxt to be used
383 *
384 * This function is called when the caller is about to add or remove
385 * kernfs_node. This function acquires kernfs_mutex. @acxt is used
386 * to keep and pass context to other addrm functions.
387 *
388 * LOCKING:
389 * Kernel thread context (may sleep). kernfs_mutex is locked on
390 * return.
391 */
392void kernfs_addrm_start(struct kernfs_addrm_cxt *acxt)
393 __acquires(kernfs_mutex)
394{
395 memset(acxt, 0, sizeof(*acxt));
396
397 mutex_lock(&kernfs_mutex);
398}
399
400/**
401 * kernfs_add_one - add kernfs_node to parent without warning
402 * @acxt: addrm context to use
403 * @kn: kernfs_node to be added
404 *
405 * The caller must already have initialized @kn->parent. This
406 * function increments nlink of the parent's inode if @kn is a
407 * directory and link into the children list of the parent.
408 *
409 * This function should be called between calls to
410 * kernfs_addrm_start() and kernfs_addrm_finish() and should be passed
411 * the same @acxt as passed to kernfs_addrm_start().
412 *
413 * LOCKING:
414 * Determined by kernfs_addrm_start().
415 *
416 * RETURNS:
417 * 0 on success, -EEXIST if entry with the given name already
418 * exists.
419 */
420int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn)
421{
422 struct kernfs_node *parent = kn->parent;
423 bool has_ns = kernfs_ns_enabled(parent);
424 struct kernfs_iattrs *ps_iattr;
425 int ret;
426
427 if (has_ns != (bool)kn->ns) {
428 WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
429 has_ns ? "required" : "invalid", parent->name, kn->name);
430 return -EINVAL;
431 }
432
433 if (kernfs_type(parent) != KERNFS_DIR)
434 return -EINVAL;
435
436 if (parent->flags & KERNFS_REMOVED)
437 return -ENOENT;
438
439 kn->hash = kernfs_name_hash(kn->name, kn->ns);
440
441 ret = kernfs_link_sibling(kn);
442 if (ret)
443 return ret;
444
445 /* Update timestamps on the parent */
446 ps_iattr = parent->iattr;
447 if (ps_iattr) {
448 struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
449 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
450 }
451
452 /* Mark the entry added into directory tree */
453 kn->flags &= ~KERNFS_REMOVED;
454
455 return 0;
456}
457
458/**
459 * kernfs_remove_one - remove kernfs_node from parent
460 * @acxt: addrm context to use
461 * @kn: kernfs_node to be removed
462 *
463 * Mark @kn removed and drop nlink of parent inode if @kn is a
464 * directory. @kn is unlinked from the children list.
465 *
466 * This function should be called between calls to
467 * kernfs_addrm_start() and kernfs_addrm_finish() and should be
468 * passed the same @acxt as passed to kernfs_addrm_start().
469 *
470 * LOCKING:
471 * Determined by kernfs_addrm_start().
472 */
473static void kernfs_remove_one(struct kernfs_addrm_cxt *acxt,
474 struct kernfs_node *kn)
475{
476 struct kernfs_iattrs *ps_iattr;
477
478 /*
479 * Removal can be called multiple times on the same node. Only the
480 * first invocation is effective and puts the base ref.
481 */
482 if (kn->flags & KERNFS_REMOVED)
483 return;
484
485 if (kn->parent) {
486 kernfs_unlink_sibling(kn);
487
488 /* Update timestamps on the parent */
489 ps_iattr = kn->parent->iattr;
490 if (ps_iattr) {
491 ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
492 ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
493 }
494 }
495
496 kn->flags |= KERNFS_REMOVED;
497 kn->u.removed_list = acxt->removed;
498 acxt->removed = kn;
499}
500
501/**
502 * kernfs_addrm_finish - finish up kernfs_node add/remove
503 * @acxt: addrm context to finish up
504 *
505 * Finish up kernfs_node add/remove. Resources acquired by
506 * kernfs_addrm_start() are released and removed kernfs_nodes are
507 * cleaned up.
508 *
509 * LOCKING:
510 * kernfs_mutex is released.
511 */
512void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt)
513 __releases(kernfs_mutex)
514{
515 /* release resources acquired by kernfs_addrm_start() */
516 mutex_unlock(&kernfs_mutex);
517
518 /* kill removed kernfs_nodes */
519 while (acxt->removed) {
520 struct kernfs_node *kn = acxt->removed;
521
522 acxt->removed = kn->u.removed_list;
523
524 kernfs_deactivate(kn);
525 kernfs_unmap_bin_file(kn);
526 kernfs_put(kn);
527 }
528}
529
530/**
531 * kernfs_find_ns - find kernfs_node with the given name
532 * @parent: kernfs_node to search under
533 * @name: name to look for
534 * @ns: the namespace tag to use
535 *
536 * Look for kernfs_node with name @name under @parent. Returns pointer to
537 * the found kernfs_node on success, %NULL on failure.
538 */
539static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
540 const unsigned char *name,
541 const void *ns)
542{
543 struct rb_node *node = parent->dir.children.rb_node;
544 bool has_ns = kernfs_ns_enabled(parent);
545 unsigned int hash;
546
547 lockdep_assert_held(&kernfs_mutex);
548
549 if (has_ns != (bool)ns) {
550 WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
551 has_ns ? "required" : "invalid", parent->name, name);
552 return NULL;
553 }
554
555 hash = kernfs_name_hash(name, ns);
556 while (node) {
557 struct kernfs_node *kn;
558 int result;
559
560 kn = rb_to_kn(node);
561 result = kernfs_name_compare(hash, name, ns, kn);
562 if (result < 0)
563 node = node->rb_left;
564 else if (result > 0)
565 node = node->rb_right;
566 else
567 return kn;
568 }
569 return NULL;
570}
571
572/**
573 * kernfs_find_and_get_ns - find and get kernfs_node with the given name
574 * @parent: kernfs_node to search under
575 * @name: name to look for
576 * @ns: the namespace tag to use
577 *
578 * Look for kernfs_node with name @name under @parent and get a reference
579 * if found. This function may sleep and returns pointer to the found
580 * kernfs_node on success, %NULL on failure.
581 */
582struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
583 const char *name, const void *ns)
584{
585 struct kernfs_node *kn;
586
587 mutex_lock(&kernfs_mutex);
588 kn = kernfs_find_ns(parent, name, ns);
589 kernfs_get(kn);
590 mutex_unlock(&kernfs_mutex);
591
592 return kn;
593}
594EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
595
596/**
597 * kernfs_create_root - create a new kernfs hierarchy
598 * @kdops: optional directory syscall operations for the hierarchy
599 * @priv: opaque data associated with the new directory
600 *
601 * Returns the root of the new hierarchy on success, ERR_PTR() value on
602 * failure.
603 */
604struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
605{
606 struct kernfs_root *root;
607 struct kernfs_node *kn;
608
609 root = kzalloc(sizeof(*root), GFP_KERNEL);
610 if (!root)
611 return ERR_PTR(-ENOMEM);
612
613 ida_init(&root->ino_ida);
614
615 kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO,
616 KERNFS_DIR);
617 if (!kn) {
618 ida_destroy(&root->ino_ida);
619 kfree(root);
620 return ERR_PTR(-ENOMEM);
621 }
622
623 kn->flags &= ~KERNFS_REMOVED;
624 kn->priv = priv;
625 kn->dir.root = root;
626
627 root->dir_ops = kdops;
628 root->kn = kn;
629
630 return root;
631}
632
633/**
634 * kernfs_destroy_root - destroy a kernfs hierarchy
635 * @root: root of the hierarchy to destroy
636 *
637 * Destroy the hierarchy anchored at @root by removing all existing
638 * directories and destroying @root.
639 */
640void kernfs_destroy_root(struct kernfs_root *root)
641{
642 kernfs_remove(root->kn); /* will also free @root */
643}
644
645/**
646 * kernfs_create_dir_ns - create a directory
647 * @parent: parent in which to create a new directory
648 * @name: name of the new directory
649 * @mode: mode of the new directory
650 * @priv: opaque data associated with the new directory
651 * @ns: optional namespace tag of the directory
652 *
653 * Returns the created node on success, ERR_PTR() value on failure.
654 */
655struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
656 const char *name, umode_t mode,
657 void *priv, const void *ns)
658{
659 struct kernfs_addrm_cxt acxt;
660 struct kernfs_node *kn;
661 int rc;
662
663 /* allocate */
664 kn = kernfs_new_node(parent, name, mode | S_IFDIR, KERNFS_DIR);
665 if (!kn)
666 return ERR_PTR(-ENOMEM);
667
668 kn->dir.root = parent->dir.root;
669 kn->ns = ns;
670 kn->priv = priv;
671
672 /* link in */
673 kernfs_addrm_start(&acxt);
674 rc = kernfs_add_one(&acxt, kn);
675 kernfs_addrm_finish(&acxt);
676
677 if (!rc)
678 return kn;
679
680 kernfs_put(kn);
681 return ERR_PTR(rc);
682}
683
684static struct dentry *kernfs_iop_lookup(struct inode *dir,
685 struct dentry *dentry,
686 unsigned int flags)
687{
688 struct dentry *ret;
689 struct kernfs_node *parent = dentry->d_parent->d_fsdata;
690 struct kernfs_node *kn;
691 struct inode *inode;
692 const void *ns = NULL;
693
694 mutex_lock(&kernfs_mutex);
695
696 if (kernfs_ns_enabled(parent))
697 ns = kernfs_info(dir->i_sb)->ns;
698
699 kn = kernfs_find_ns(parent, dentry->d_name.name, ns);
700
701 /* no such entry */
702 if (!kn) {
703 ret = NULL;
704 goto out_unlock;
705 }
706 kernfs_get(kn);
707 dentry->d_fsdata = kn;
708
709 /* attach dentry and inode */
710 inode = kernfs_get_inode(dir->i_sb, kn);
711 if (!inode) {
712 ret = ERR_PTR(-ENOMEM);
713 goto out_unlock;
714 }
715
716 /* instantiate and hash dentry */
717 ret = d_materialise_unique(dentry, inode);
718 out_unlock:
719 mutex_unlock(&kernfs_mutex);
720 return ret;
721}
722
723static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
724 umode_t mode)
725{
726 struct kernfs_node *parent = dir->i_private;
727 struct kernfs_dir_ops *kdops = kernfs_root(parent)->dir_ops;
728
729 if (!kdops || !kdops->mkdir)
730 return -EPERM;
731
732 return kdops->mkdir(parent, dentry->d_name.name, mode);
733}
734
735static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
736{
737 struct kernfs_node *kn = dentry->d_fsdata;
738 struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
739
740 if (!kdops || !kdops->rmdir)
741 return -EPERM;
742
743 return kdops->rmdir(kn);
744}
745
746static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
747 struct inode *new_dir, struct dentry *new_dentry)
748{
749 struct kernfs_node *kn = old_dentry->d_fsdata;
750 struct kernfs_node *new_parent = new_dir->i_private;
751 struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
752
753 if (!kdops || !kdops->rename)
754 return -EPERM;
755
756 return kdops->rename(kn, new_parent, new_dentry->d_name.name);
757}
758
759const struct inode_operations kernfs_dir_iops = {
760 .lookup = kernfs_iop_lookup,
761 .permission = kernfs_iop_permission,
762 .setattr = kernfs_iop_setattr,
763 .getattr = kernfs_iop_getattr,
764 .setxattr = kernfs_iop_setxattr,
765 .removexattr = kernfs_iop_removexattr,
766 .getxattr = kernfs_iop_getxattr,
767 .listxattr = kernfs_iop_listxattr,
768
769 .mkdir = kernfs_iop_mkdir,
770 .rmdir = kernfs_iop_rmdir,
771 .rename = kernfs_iop_rename,
772};
773
774static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos)
775{
776 struct kernfs_node *last;
777
778 while (true) {
779 struct rb_node *rbn;
780
781 last = pos;
782
783 if (kernfs_type(pos) != KERNFS_DIR)
784 break;
785
786 rbn = rb_first(&pos->dir.children);
787 if (!rbn)
788 break;
789
790 pos = rb_to_kn(rbn);
791 }
792
793 return last;
794}
795
796/**
797 * kernfs_next_descendant_post - find the next descendant for post-order walk
798 * @pos: the current position (%NULL to initiate traversal)
799 * @root: kernfs_node whose descendants to walk
800 *
801 * Find the next descendant to visit for post-order traversal of @root's
802 * descendants. @root is included in the iteration and the last node to be
803 * visited.
804 */
805static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos,
806 struct kernfs_node *root)
807{
808 struct rb_node *rbn;
809
810 lockdep_assert_held(&kernfs_mutex);
811
812 /* if first iteration, visit leftmost descendant which may be root */
813 if (!pos)
814 return kernfs_leftmost_descendant(root);
815
816 /* if we visited @root, we're done */
817 if (pos == root)
818 return NULL;
819
820 /* if there's an unvisited sibling, visit its leftmost descendant */
821 rbn = rb_next(&pos->rb);
822 if (rbn)
823 return kernfs_leftmost_descendant(rb_to_kn(rbn));
824
825 /* no sibling left, visit parent */
826 return pos->parent;
827}
828
829static void __kernfs_remove(struct kernfs_addrm_cxt *acxt,
830 struct kernfs_node *kn)
831{
832 struct kernfs_node *pos, *next;
833
834 if (!kn)
835 return;
836
837 pr_debug("kernfs %s: removing\n", kn->name);
838
839 next = NULL;
840 do {
841 pos = next;
842 next = kernfs_next_descendant_post(pos, kn);
843 if (pos)
844 kernfs_remove_one(acxt, pos);
845 } while (next);
846}
847
848/**
849 * kernfs_remove - remove a kernfs_node recursively
850 * @kn: the kernfs_node to remove
851 *
852 * Remove @kn along with all its subdirectories and files.
853 */
854void kernfs_remove(struct kernfs_node *kn)
855{
856 struct kernfs_addrm_cxt acxt;
857
858 kernfs_addrm_start(&acxt);
859 __kernfs_remove(&acxt, kn);
860 kernfs_addrm_finish(&acxt);
861}
862
863/**
864 * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it
865 * @parent: parent of the target
866 * @name: name of the kernfs_node to remove
867 * @ns: namespace tag of the kernfs_node to remove
868 *
869 * Look for the kernfs_node with @name and @ns under @parent and remove it.
870 * Returns 0 on success, -ENOENT if such entry doesn't exist.
871 */
872int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
873 const void *ns)
874{
875 struct kernfs_addrm_cxt acxt;
876 struct kernfs_node *kn;
877
878 if (!parent) {
879 WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n",
880 name);
881 return -ENOENT;
882 }
883
884 kernfs_addrm_start(&acxt);
885
886 kn = kernfs_find_ns(parent, name, ns);
887 if (kn)
888 __kernfs_remove(&acxt, kn);
889
890 kernfs_addrm_finish(&acxt);
891
892 if (kn)
893 return 0;
894 else
895 return -ENOENT;
896}
897
898/**
899 * kernfs_rename_ns - move and rename a kernfs_node
900 * @kn: target node
901 * @new_parent: new parent to put @sd under
902 * @new_name: new name
903 * @new_ns: new namespace tag
904 */
905int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
906 const char *new_name, const void *new_ns)
907{
908 int error;
909
910 mutex_lock(&kernfs_mutex);
911
912 error = -ENOENT;
913 if ((kn->flags | new_parent->flags) & KERNFS_REMOVED)
914 goto out;
915
916 error = 0;
917 if ((kn->parent == new_parent) && (kn->ns == new_ns) &&
918 (strcmp(kn->name, new_name) == 0))
919 goto out; /* nothing to rename */
920
921 error = -EEXIST;
922 if (kernfs_find_ns(new_parent, new_name, new_ns))
923 goto out;
924
925 /* rename kernfs_node */
926 if (strcmp(kn->name, new_name) != 0) {
927 error = -ENOMEM;
928 new_name = kstrdup(new_name, GFP_KERNEL);
929 if (!new_name)
930 goto out;
931
932 if (kn->flags & KERNFS_STATIC_NAME)
933 kn->flags &= ~KERNFS_STATIC_NAME;
934 else
935 kfree(kn->name);
936
937 kn->name = new_name;
938 }
939
940 /*
941 * Move to the appropriate place in the appropriate directories rbtree.
942 */
943 kernfs_unlink_sibling(kn);
944 kernfs_get(new_parent);
945 kernfs_put(kn->parent);
946 kn->ns = new_ns;
947 kn->hash = kernfs_name_hash(kn->name, kn->ns);
948 kn->parent = new_parent;
949 kernfs_link_sibling(kn);
950
951 error = 0;
952 out:
953 mutex_unlock(&kernfs_mutex);
954 return error;
955}
956
957/* Relationship between s_mode and the DT_xxx types */
958static inline unsigned char dt_type(struct kernfs_node *kn)
959{
960 return (kn->mode >> 12) & 15;
961}
962
963static int kernfs_dir_fop_release(struct inode *inode, struct file *filp)
964{
965 kernfs_put(filp->private_data);
966 return 0;
967}
968
969static struct kernfs_node *kernfs_dir_pos(const void *ns,
970 struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos)
971{
972 if (pos) {
973 int valid = !(pos->flags & KERNFS_REMOVED) &&
974 pos->parent == parent && hash == pos->hash;
975 kernfs_put(pos);
976 if (!valid)
977 pos = NULL;
978 }
979 if (!pos && (hash > 1) && (hash < INT_MAX)) {
980 struct rb_node *node = parent->dir.children.rb_node;
981 while (node) {
982 pos = rb_to_kn(node);
983
984 if (hash < pos->hash)
985 node = node->rb_left;
986 else if (hash > pos->hash)
987 node = node->rb_right;
988 else
989 break;
990 }
991 }
992 /* Skip over entries in the wrong namespace */
993 while (pos && pos->ns != ns) {
994 struct rb_node *node = rb_next(&pos->rb);
995 if (!node)
996 pos = NULL;
997 else
998 pos = rb_to_kn(node);
999 }
1000 return pos;
1001}
1002
1003static struct kernfs_node *kernfs_dir_next_pos(const void *ns,
1004 struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos)
1005{
1006 pos = kernfs_dir_pos(ns, parent, ino, pos);
1007 if (pos)
1008 do {
1009 struct rb_node *node = rb_next(&pos->rb);
1010 if (!node)
1011 pos = NULL;
1012 else
1013 pos = rb_to_kn(node);
1014 } while (pos && pos->ns != ns);
1015 return pos;
1016}
1017
1018static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
1019{
1020 struct dentry *dentry = file->f_path.dentry;
1021 struct kernfs_node *parent = dentry->d_fsdata;
1022 struct kernfs_node *pos = file->private_data;
1023 const void *ns = NULL;
1024
1025 if (!dir_emit_dots(file, ctx))
1026 return 0;
1027 mutex_lock(&kernfs_mutex);
1028
1029 if (kernfs_ns_enabled(parent))
1030 ns = kernfs_info(dentry->d_sb)->ns;
1031
1032 for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos);
1033 pos;
1034 pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) {
1035 const char *name = pos->name;
1036 unsigned int type = dt_type(pos);
1037 int len = strlen(name);
1038 ino_t ino = pos->ino;
1039
1040 ctx->pos = pos->hash;
1041 file->private_data = pos;
1042 kernfs_get(pos);
1043
1044 mutex_unlock(&kernfs_mutex);
1045 if (!dir_emit(ctx, name, len, ino, type))
1046 return 0;
1047 mutex_lock(&kernfs_mutex);
1048 }
1049 mutex_unlock(&kernfs_mutex);
1050 file->private_data = NULL;
1051 ctx->pos = INT_MAX;
1052 return 0;
1053}
1054
1055static loff_t kernfs_dir_fop_llseek(struct file *file, loff_t offset,
1056 int whence)
1057{
1058 struct inode *inode = file_inode(file);
1059 loff_t ret;
1060
1061 mutex_lock(&inode->i_mutex);
1062 ret = generic_file_llseek(file, offset, whence);
1063 mutex_unlock(&inode->i_mutex);
1064
1065 return ret;
1066}
1067
1068const struct file_operations kernfs_dir_fops = {
1069 .read = generic_read_dir,
1070 .iterate = kernfs_fop_readdir,
1071 .release = kernfs_dir_fop_release,
1072 .llseek = kernfs_dir_fop_llseek,
1073};
generated by cgit v1.2.2 (git 2.25.0) at 2025-01-13 04:20:14 -0500