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7#include <linux/blkdev.h>
8#include <linux/export.h>
9#include <linux/pagemap.h>
10#include <linux/slab.h>
11#include <linux/cred.h>
12#include <linux/mount.h>
13#include <linux/vfs.h>
14#include <linux/quotaops.h>
15#include <linux/mutex.h>
16#include <linux/namei.h>
17#include <linux/exportfs.h>
18#include <linux/writeback.h>
19#include <linux/buffer_head.h>
20
21#include <linux/uaccess.h>
22
23#include "internal.h"
24
25int simple_getattr(const struct path *path, struct kstat *stat,
26 u32 request_mask, unsigned int query_flags)
27{
28 struct inode *inode = d_inode(path->dentry);
29 generic_fillattr(inode, stat);
30 stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9);
31 return 0;
32}
33EXPORT_SYMBOL(simple_getattr);
34
35int simple_statfs(struct dentry *dentry, struct kstatfs *buf)
36{
37 buf->f_type = dentry->d_sb->s_magic;
38 buf->f_bsize = PAGE_SIZE;
39 buf->f_namelen = NAME_MAX;
40 return 0;
41}
42EXPORT_SYMBOL(simple_statfs);
43
44
45
46
47
48int always_delete_dentry(const struct dentry *dentry)
49{
50 return 1;
51}
52EXPORT_SYMBOL(always_delete_dentry);
53
54const struct dentry_operations simple_dentry_operations = {
55 .d_delete = always_delete_dentry,
56};
57EXPORT_SYMBOL(simple_dentry_operations);
58
59
60
61
62
63struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
64{
65 if (dentry->d_name.len > NAME_MAX)
66 return ERR_PTR(-ENAMETOOLONG);
67 if (!dentry->d_sb->s_d_op)
68 d_set_d_op(dentry, &simple_dentry_operations);
69 d_add(dentry, NULL);
70 return NULL;
71}
72EXPORT_SYMBOL(simple_lookup);
73
74int dcache_dir_open(struct inode *inode, struct file *file)
75{
76 file->private_data = d_alloc_cursor(file->f_path.dentry);
77
78 return file->private_data ? 0 : -ENOMEM;
79}
80EXPORT_SYMBOL(dcache_dir_open);
81
82int dcache_dir_close(struct inode *inode, struct file *file)
83{
84 dput(file->private_data);
85 return 0;
86}
87EXPORT_SYMBOL(dcache_dir_close);
88
89
90static struct dentry *next_positive(struct dentry *parent,
91 struct list_head *from,
92 int count)
93{
94 unsigned *seq = &parent->d_inode->i_dir_seq, n;
95 struct dentry *res;
96 struct list_head *p;
97 bool skipped;
98 int i;
99
100retry:
101 i = count;
102 skipped = false;
103 n = smp_load_acquire(seq) & ~1;
104 res = NULL;
105 rcu_read_lock();
106 for (p = from->next; p != &parent->d_subdirs; p = p->next) {
107 struct dentry *d = list_entry(p, struct dentry, d_child);
108 if (!simple_positive(d)) {
109 skipped = true;
110 } else if (!--i) {
111 res = d;
112 break;
113 }
114 }
115 rcu_read_unlock();
116 if (skipped) {
117 smp_rmb();
118 if (unlikely(*seq != n))
119 goto retry;
120 }
121 return res;
122}
123
124static void move_cursor(struct dentry *cursor, struct list_head *after)
125{
126 struct dentry *parent = cursor->d_parent;
127 unsigned n, *seq = &parent->d_inode->i_dir_seq;
128 spin_lock(&parent->d_lock);
129 for (;;) {
130 n = *seq;
131 if (!(n & 1) && cmpxchg(seq, n, n + 1) == n)
132 break;
133 cpu_relax();
134 }
135 __list_del(cursor->d_child.prev, cursor->d_child.next);
136 if (after)
137 list_add(&cursor->d_child, after);
138 else
139 list_add_tail(&cursor->d_child, &parent->d_subdirs);
140 smp_store_release(seq, n + 2);
141 spin_unlock(&parent->d_lock);
142}
143
144loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence)
145{
146 struct dentry *dentry = file->f_path.dentry;
147 switch (whence) {
148 case 1:
149 offset += file->f_pos;
150
151 case 0:
152 if (offset >= 0)
153 break;
154
155 default:
156 return -EINVAL;
157 }
158 if (offset != file->f_pos) {
159 file->f_pos = offset;
160 if (file->f_pos >= 2) {
161 struct dentry *cursor = file->private_data;
162 struct dentry *to;
163 loff_t n = file->f_pos - 2;
164
165 inode_lock_shared(dentry->d_inode);
166 to = next_positive(dentry, &dentry->d_subdirs, n);
167 move_cursor(cursor, to ? &to->d_child : NULL);
168 inode_unlock_shared(dentry->d_inode);
169 }
170 }
171 return offset;
172}
173EXPORT_SYMBOL(dcache_dir_lseek);
174
175
176static inline unsigned char dt_type(struct inode *inode)
177{
178 return (inode->i_mode >> 12) & 15;
179}
180
181
182
183
184
185
186
187int dcache_readdir(struct file *file, struct dir_context *ctx)
188{
189 struct dentry *dentry = file->f_path.dentry;
190 struct dentry *cursor = file->private_data;
191 struct list_head *p = &cursor->d_child;
192 struct dentry *next;
193 bool moved = false;
194
195 if (!dir_emit_dots(file, ctx))
196 return 0;
197
198 if (ctx->pos == 2)
199 p = &dentry->d_subdirs;
200 while ((next = next_positive(dentry, p, 1)) != NULL) {
201 if (!dir_emit(ctx, next->d_name.name, next->d_name.len,
202 d_inode(next)->i_ino, dt_type(d_inode(next))))
203 break;
204 moved = true;
205 p = &next->d_child;
206 ctx->pos++;
207 }
208 if (moved)
209 move_cursor(cursor, p);
210 return 0;
211}
212EXPORT_SYMBOL(dcache_readdir);
213
214ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos)
215{
216 return -EISDIR;
217}
218EXPORT_SYMBOL(generic_read_dir);
219
220const struct file_operations simple_dir_operations = {
221 .open = dcache_dir_open,
222 .release = dcache_dir_close,
223 .llseek = dcache_dir_lseek,
224 .read = generic_read_dir,
225 .iterate_shared = dcache_readdir,
226 .fsync = noop_fsync,
227};
228EXPORT_SYMBOL(simple_dir_operations);
229
230const struct inode_operations simple_dir_inode_operations = {
231 .lookup = simple_lookup,
232};
233EXPORT_SYMBOL(simple_dir_inode_operations);
234
235static const struct super_operations simple_super_operations = {
236 .statfs = simple_statfs,
237};
238
239
240
241
242
243struct dentry *mount_pseudo_xattr(struct file_system_type *fs_type, char *name,
244 const struct super_operations *ops, const struct xattr_handler **xattr,
245 const struct dentry_operations *dops, unsigned long magic)
246{
247 struct super_block *s;
248 struct dentry *dentry;
249 struct inode *root;
250 struct qstr d_name = QSTR_INIT(name, strlen(name));
251
252 s = sget_userns(fs_type, NULL, set_anon_super, SB_KERNMOUNT|SB_NOUSER,
253 &init_user_ns, NULL);
254 if (IS_ERR(s))
255 return ERR_CAST(s);
256
257 s->s_maxbytes = MAX_LFS_FILESIZE;
258 s->s_blocksize = PAGE_SIZE;
259 s->s_blocksize_bits = PAGE_SHIFT;
260 s->s_magic = magic;
261 s->s_op = ops ? ops : &simple_super_operations;
262 s->s_xattr = xattr;
263 s->s_time_gran = 1;
264 root = new_inode(s);
265 if (!root)
266 goto Enomem;
267
268
269
270
271
272 root->i_ino = 1;
273 root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
274 root->i_atime = root->i_mtime = root->i_ctime = current_time(root);
275 dentry = __d_alloc(s, &d_name);
276 if (!dentry) {
277 iput(root);
278 goto Enomem;
279 }
280 d_instantiate(dentry, root);
281 s->s_root = dentry;
282 s->s_d_op = dops;
283 s->s_flags |= SB_ACTIVE;
284 return dget(s->s_root);
285
286Enomem:
287 deactivate_locked_super(s);
288 return ERR_PTR(-ENOMEM);
289}
290EXPORT_SYMBOL(mount_pseudo_xattr);
291
292int simple_open(struct inode *inode, struct file *file)
293{
294 if (inode->i_private)
295 file->private_data = inode->i_private;
296 return 0;
297}
298EXPORT_SYMBOL(simple_open);
299
300int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
301{
302 struct inode *inode = d_inode(old_dentry);
303
304 inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
305 inc_nlink(inode);
306 ihold(inode);
307 dget(dentry);
308 d_instantiate(dentry, inode);
309 return 0;
310}
311EXPORT_SYMBOL(simple_link);
312
313int simple_empty(struct dentry *dentry)
314{
315 struct dentry *child;
316 int ret = 0;
317
318 spin_lock(&dentry->d_lock);
319 list_for_each_entry(child, &dentry->d_subdirs, d_child) {
320 spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
321 if (simple_positive(child)) {
322 spin_unlock(&child->d_lock);
323 goto out;
324 }
325 spin_unlock(&child->d_lock);
326 }
327 ret = 1;
328out:
329 spin_unlock(&dentry->d_lock);
330 return ret;
331}
332EXPORT_SYMBOL(simple_empty);
333
334int simple_unlink(struct inode *dir, struct dentry *dentry)
335{
336 struct inode *inode = d_inode(dentry);
337
338 inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
339 drop_nlink(inode);
340 dput(dentry);
341 return 0;
342}
343EXPORT_SYMBOL(simple_unlink);
344
345int simple_rmdir(struct inode *dir, struct dentry *dentry)
346{
347 if (!simple_empty(dentry))
348 return -ENOTEMPTY;
349
350 drop_nlink(d_inode(dentry));
351 simple_unlink(dir, dentry);
352 drop_nlink(dir);
353 return 0;
354}
355EXPORT_SYMBOL(simple_rmdir);
356
357int simple_rename(struct inode *old_dir, struct dentry *old_dentry,
358 struct inode *new_dir, struct dentry *new_dentry,
359 unsigned int flags)
360{
361 struct inode *inode = d_inode(old_dentry);
362 int they_are_dirs = d_is_dir(old_dentry);
363
364 if (flags & ~RENAME_NOREPLACE)
365 return -EINVAL;
366
367 if (!simple_empty(new_dentry))
368 return -ENOTEMPTY;
369
370 if (d_really_is_positive(new_dentry)) {
371 simple_unlink(new_dir, new_dentry);
372 if (they_are_dirs) {
373 drop_nlink(d_inode(new_dentry));
374 drop_nlink(old_dir);
375 }
376 } else if (they_are_dirs) {
377 drop_nlink(old_dir);
378 inc_nlink(new_dir);
379 }
380
381 old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
382 new_dir->i_mtime = inode->i_ctime = current_time(old_dir);
383
384 return 0;
385}
386EXPORT_SYMBOL(simple_rename);
387
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399
400
401
402int simple_setattr(struct dentry *dentry, struct iattr *iattr)
403{
404 struct inode *inode = d_inode(dentry);
405 int error;
406
407 error = setattr_prepare(dentry, iattr);
408 if (error)
409 return error;
410
411 if (iattr->ia_valid & ATTR_SIZE)
412 truncate_setsize(inode, iattr->ia_size);
413 setattr_copy(inode, iattr);
414 mark_inode_dirty(inode);
415 return 0;
416}
417EXPORT_SYMBOL(simple_setattr);
418
419int simple_readpage(struct file *file, struct page *page)
420{
421 clear_highpage(page);
422 flush_dcache_page(page);
423 SetPageUptodate(page);
424 unlock_page(page);
425 return 0;
426}
427EXPORT_SYMBOL(simple_readpage);
428
429int simple_write_begin(struct file *file, struct address_space *mapping,
430 loff_t pos, unsigned len, unsigned flags,
431 struct page **pagep, void **fsdata)
432{
433 struct page *page;
434 pgoff_t index;
435
436 index = pos >> PAGE_SHIFT;
437
438 page = grab_cache_page_write_begin(mapping, index, flags);
439 if (!page)
440 return -ENOMEM;
441
442 *pagep = page;
443
444 if (!PageUptodate(page) && (len != PAGE_SIZE)) {
445 unsigned from = pos & (PAGE_SIZE - 1);
446
447 zero_user_segments(page, 0, from, from + len, PAGE_SIZE);
448 }
449 return 0;
450}
451EXPORT_SYMBOL(simple_write_begin);
452
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476int simple_write_end(struct file *file, struct address_space *mapping,
477 loff_t pos, unsigned len, unsigned copied,
478 struct page *page, void *fsdata)
479{
480 struct inode *inode = page->mapping->host;
481 loff_t last_pos = pos + copied;
482
483
484 if (!PageUptodate(page)) {
485 if (copied < len) {
486 unsigned from = pos & (PAGE_SIZE - 1);
487
488 zero_user(page, from + copied, len - copied);
489 }
490 SetPageUptodate(page);
491 }
492
493
494
495
496 if (last_pos > inode->i_size)
497 i_size_write(inode, last_pos);
498
499 set_page_dirty(page);
500 unlock_page(page);
501 put_page(page);
502
503 return copied;
504}
505EXPORT_SYMBOL(simple_write_end);
506
507
508
509
510
511
512int simple_fill_super(struct super_block *s, unsigned long magic,
513 const struct tree_descr *files)
514{
515 struct inode *inode;
516 struct dentry *root;
517 struct dentry *dentry;
518 int i;
519
520 s->s_blocksize = PAGE_SIZE;
521 s->s_blocksize_bits = PAGE_SHIFT;
522 s->s_magic = magic;
523 s->s_op = &simple_super_operations;
524 s->s_time_gran = 1;
525
526 inode = new_inode(s);
527 if (!inode)
528 return -ENOMEM;
529
530
531
532
533 inode->i_ino = 1;
534 inode->i_mode = S_IFDIR | 0755;
535 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
536 inode->i_op = &simple_dir_inode_operations;
537 inode->i_fop = &simple_dir_operations;
538 set_nlink(inode, 2);
539 root = d_make_root(inode);
540 if (!root)
541 return -ENOMEM;
542 for (i = 0; !files->name || files->name[0]; i++, files++) {
543 if (!files->name)
544 continue;
545
546
547 if (unlikely(i == 1))
548 printk(KERN_WARNING "%s: %s passed in a files array"
549 "with an index of 1!\n", __func__,
550 s->s_type->name);
551
552 dentry = d_alloc_name(root, files->name);
553 if (!dentry)
554 goto out;
555 inode = new_inode(s);
556 if (!inode) {
557 dput(dentry);
558 goto out;
559 }
560 inode->i_mode = S_IFREG | files->mode;
561 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
562 inode->i_fop = files->ops;
563 inode->i_ino = i;
564 d_add(dentry, inode);
565 }
566 s->s_root = root;
567 return 0;
568out:
569 d_genocide(root);
570 shrink_dcache_parent(root);
571 dput(root);
572 return -ENOMEM;
573}
574EXPORT_SYMBOL(simple_fill_super);
575
576static DEFINE_SPINLOCK(pin_fs_lock);
577
578int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count)
579{
580 struct vfsmount *mnt = NULL;
581 spin_lock(&pin_fs_lock);
582 if (unlikely(!*mount)) {
583 spin_unlock(&pin_fs_lock);
584 mnt = vfs_kern_mount(type, SB_KERNMOUNT, type->name, NULL);
585 if (IS_ERR(mnt))
586 return PTR_ERR(mnt);
587 spin_lock(&pin_fs_lock);
588 if (!*mount)
589 *mount = mnt;
590 }
591 mntget(*mount);
592 ++*count;
593 spin_unlock(&pin_fs_lock);
594 mntput(mnt);
595 return 0;
596}
597EXPORT_SYMBOL(simple_pin_fs);
598
599void simple_release_fs(struct vfsmount **mount, int *count)
600{
601 struct vfsmount *mnt;
602 spin_lock(&pin_fs_lock);
603 mnt = *mount;
604 if (!--*count)
605 *mount = NULL;
606 spin_unlock(&pin_fs_lock);
607 mntput(mnt);
608}
609EXPORT_SYMBOL(simple_release_fs);
610
611
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615
616
617
618
619
620
621
622
623
624
625ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
626 const void *from, size_t available)
627{
628 loff_t pos = *ppos;
629 size_t ret;
630
631 if (pos < 0)
632 return -EINVAL;
633 if (pos >= available || !count)
634 return 0;
635 if (count > available - pos)
636 count = available - pos;
637 ret = copy_to_user(to, from + pos, count);
638 if (ret == count)
639 return -EFAULT;
640 count -= ret;
641 *ppos = pos + count;
642 return count;
643}
644EXPORT_SYMBOL(simple_read_from_buffer);
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
661 const void __user *from, size_t count)
662{
663 loff_t pos = *ppos;
664 size_t res;
665
666 if (pos < 0)
667 return -EINVAL;
668 if (pos >= available || !count)
669 return 0;
670 if (count > available - pos)
671 count = available - pos;
672 res = copy_from_user(to + pos, from, count);
673 if (res == count)
674 return -EFAULT;
675 count -= res;
676 *ppos = pos + count;
677 return count;
678}
679EXPORT_SYMBOL(simple_write_to_buffer);
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
696 const void *from, size_t available)
697{
698 loff_t pos = *ppos;
699
700 if (pos < 0)
701 return -EINVAL;
702 if (pos >= available)
703 return 0;
704 if (count > available - pos)
705 count = available - pos;
706 memcpy(to, from + pos, count);
707 *ppos = pos + count;
708
709 return count;
710}
711EXPORT_SYMBOL(memory_read_from_buffer);
712
713
714
715
716
717
718
719
720void simple_transaction_set(struct file *file, size_t n)
721{
722 struct simple_transaction_argresp *ar = file->private_data;
723
724 BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
725
726
727
728
729
730 smp_mb();
731 ar->size = n;
732}
733EXPORT_SYMBOL(simple_transaction_set);
734
735char *simple_transaction_get(struct file *file, const char __user *buf, size_t size)
736{
737 struct simple_transaction_argresp *ar;
738 static DEFINE_SPINLOCK(simple_transaction_lock);
739
740 if (size > SIMPLE_TRANSACTION_LIMIT - 1)
741 return ERR_PTR(-EFBIG);
742
743 ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL);
744 if (!ar)
745 return ERR_PTR(-ENOMEM);
746
747 spin_lock(&simple_transaction_lock);
748
749
750 if (file->private_data) {
751 spin_unlock(&simple_transaction_lock);
752 free_page((unsigned long)ar);
753 return ERR_PTR(-EBUSY);
754 }
755
756 file->private_data = ar;
757
758 spin_unlock(&simple_transaction_lock);
759
760 if (copy_from_user(ar->data, buf, size))
761 return ERR_PTR(-EFAULT);
762
763 return ar->data;
764}
765EXPORT_SYMBOL(simple_transaction_get);
766
767ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
768{
769 struct simple_transaction_argresp *ar = file->private_data;
770
771 if (!ar)
772 return 0;
773 return simple_read_from_buffer(buf, size, pos, ar->data, ar->size);
774}
775EXPORT_SYMBOL(simple_transaction_read);
776
777int simple_transaction_release(struct inode *inode, struct file *file)
778{
779 free_page((unsigned long)file->private_data);
780 return 0;
781}
782EXPORT_SYMBOL(simple_transaction_release);
783
784
785
786struct simple_attr {
787 int (*get)(void *, u64 *);
788 int (*set)(void *, u64);
789 char get_buf[24];
790 char set_buf[24];
791 void *data;
792 const char *fmt;
793 struct mutex mutex;
794};
795
796
797
798int simple_attr_open(struct inode *inode, struct file *file,
799 int (*get)(void *, u64 *), int (*set)(void *, u64),
800 const char *fmt)
801{
802 struct simple_attr *attr;
803
804 attr = kmalloc(sizeof(*attr), GFP_KERNEL);
805 if (!attr)
806 return -ENOMEM;
807
808 attr->get = get;
809 attr->set = set;
810 attr->data = inode->i_private;
811 attr->fmt = fmt;
812 mutex_init(&attr->mutex);
813
814 file->private_data = attr;
815
816 return nonseekable_open(inode, file);
817}
818EXPORT_SYMBOL_GPL(simple_attr_open);
819
820int simple_attr_release(struct inode *inode, struct file *file)
821{
822 kfree(file->private_data);
823 return 0;
824}
825EXPORT_SYMBOL_GPL(simple_attr_release);
826
827
828ssize_t simple_attr_read(struct file *file, char __user *buf,
829 size_t len, loff_t *ppos)
830{
831 struct simple_attr *attr;
832 size_t size;
833 ssize_t ret;
834
835 attr = file->private_data;
836
837 if (!attr->get)
838 return -EACCES;
839
840 ret = mutex_lock_interruptible(&attr->mutex);
841 if (ret)
842 return ret;
843
844 if (*ppos) {
845 size = strlen(attr->get_buf);
846 } else {
847 u64 val;
848 ret = attr->get(attr->data, &val);
849 if (ret)
850 goto out;
851
852 size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
853 attr->fmt, (unsigned long long)val);
854 }
855
856 ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
857out:
858 mutex_unlock(&attr->mutex);
859 return ret;
860}
861EXPORT_SYMBOL_GPL(simple_attr_read);
862
863
864ssize_t simple_attr_write(struct file *file, const char __user *buf,
865 size_t len, loff_t *ppos)
866{
867 struct simple_attr *attr;
868 u64 val;
869 size_t size;
870 ssize_t ret;
871
872 attr = file->private_data;
873 if (!attr->set)
874 return -EACCES;
875
876 ret = mutex_lock_interruptible(&attr->mutex);
877 if (ret)
878 return ret;
879
880 ret = -EFAULT;
881 size = min(sizeof(attr->set_buf) - 1, len);
882 if (copy_from_user(attr->set_buf, buf, size))
883 goto out;
884
885 attr->set_buf[size] = '\0';
886 val = simple_strtoll(attr->set_buf, NULL, 0);
887 ret = attr->set(attr->data, val);
888 if (ret == 0)
889 ret = len;
890out:
891 mutex_unlock(&attr->mutex);
892 return ret;
893}
894EXPORT_SYMBOL_GPL(simple_attr_write);
895
896
897
898
899
900
901
902
903
904
905
906
907
908struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid,
909 int fh_len, int fh_type, struct inode *(*get_inode)
910 (struct super_block *sb, u64 ino, u32 gen))
911{
912 struct inode *inode = NULL;
913
914 if (fh_len < 2)
915 return NULL;
916
917 switch (fh_type) {
918 case FILEID_INO32_GEN:
919 case FILEID_INO32_GEN_PARENT:
920 inode = get_inode(sb, fid->i32.ino, fid->i32.gen);
921 break;
922 }
923
924 return d_obtain_alias(inode);
925}
926EXPORT_SYMBOL_GPL(generic_fh_to_dentry);
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
942 int fh_len, int fh_type, struct inode *(*get_inode)
943 (struct super_block *sb, u64 ino, u32 gen))
944{
945 struct inode *inode = NULL;
946
947 if (fh_len <= 2)
948 return NULL;
949
950 switch (fh_type) {
951 case FILEID_INO32_GEN_PARENT:
952 inode = get_inode(sb, fid->i32.parent_ino,
953 (fh_len > 3 ? fid->i32.parent_gen : 0));
954 break;
955 }
956
957 return d_obtain_alias(inode);
958}
959EXPORT_SYMBOL_GPL(generic_fh_to_parent);
960
961
962
963
964
965
966
967
968
969
970
971
972
973int __generic_file_fsync(struct file *file, loff_t start, loff_t end,
974 int datasync)
975{
976 struct inode *inode = file->f_mapping->host;
977 int err;
978 int ret;
979
980 err = file_write_and_wait_range(file, start, end);
981 if (err)
982 return err;
983
984 inode_lock(inode);
985 ret = sync_mapping_buffers(inode->i_mapping);
986 if (!(inode->i_state & I_DIRTY_ALL))
987 goto out;
988 if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
989 goto out;
990
991 err = sync_inode_metadata(inode, 1);
992 if (ret == 0)
993 ret = err;
994
995out:
996 inode_unlock(inode);
997
998 err = file_check_and_advance_wb_err(file);
999 if (ret == 0)
1000 ret = err;
1001 return ret;
1002}
1003EXPORT_SYMBOL(__generic_file_fsync);
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015int generic_file_fsync(struct file *file, loff_t start, loff_t end,
1016 int datasync)
1017{
1018 struct inode *inode = file->f_mapping->host;
1019 int err;
1020
1021 err = __generic_file_fsync(file, start, end, datasync);
1022 if (err)
1023 return err;
1024 return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
1025}
1026EXPORT_SYMBOL(generic_file_fsync);
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks)
1038{
1039 u64 last_fs_block = num_blocks - 1;
1040 u64 last_fs_page =
1041 last_fs_block >> (PAGE_SHIFT - blocksize_bits);
1042
1043 if (unlikely(num_blocks == 0))
1044 return 0;
1045
1046 if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT))
1047 return -EINVAL;
1048
1049 if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) ||
1050 (last_fs_page > (pgoff_t)(~0ULL))) {
1051 return -EFBIG;
1052 }
1053 return 0;
1054}
1055EXPORT_SYMBOL(generic_check_addressable);
1056
1057
1058
1059
1060int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync)
1061{
1062 return 0;
1063}
1064EXPORT_SYMBOL(noop_fsync);
1065
1066int noop_set_page_dirty(struct page *page)
1067{
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078 return 0;
1079}
1080EXPORT_SYMBOL_GPL(noop_set_page_dirty);
1081
1082void noop_invalidatepage(struct page *page, unsigned int offset,
1083 unsigned int length)
1084{
1085
1086
1087
1088
1089
1090}
1091EXPORT_SYMBOL_GPL(noop_invalidatepage);
1092
1093ssize_t noop_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
1094{
1095
1096
1097
1098
1099
1100
1101 return -EINVAL;
1102}
1103EXPORT_SYMBOL_GPL(noop_direct_IO);
1104
1105
1106void kfree_link(void *p)
1107{
1108 kfree(p);
1109}
1110EXPORT_SYMBOL(kfree_link);
1111
1112
1113
1114
1115
1116static int anon_set_page_dirty(struct page *page)
1117{
1118 return 0;
1119};
1120
1121
1122
1123
1124
1125
1126struct inode *alloc_anon_inode(struct super_block *s)
1127{
1128 static const struct address_space_operations anon_aops = {
1129 .set_page_dirty = anon_set_page_dirty,
1130 };
1131 struct inode *inode = new_inode_pseudo(s);
1132
1133 if (!inode)
1134 return ERR_PTR(-ENOMEM);
1135
1136 inode->i_ino = get_next_ino();
1137 inode->i_mapping->a_ops = &anon_aops;
1138
1139
1140
1141
1142
1143
1144
1145 inode->i_state = I_DIRTY;
1146 inode->i_mode = S_IRUSR | S_IWUSR;
1147 inode->i_uid = current_fsuid();
1148 inode->i_gid = current_fsgid();
1149 inode->i_flags |= S_PRIVATE;
1150 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
1151 return inode;
1152}
1153EXPORT_SYMBOL(alloc_anon_inode);
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165int
1166simple_nosetlease(struct file *filp, long arg, struct file_lock **flp,
1167 void **priv)
1168{
1169 return -EINVAL;
1170}
1171EXPORT_SYMBOL(simple_nosetlease);
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187const char *simple_get_link(struct dentry *dentry, struct inode *inode,
1188 struct delayed_call *done)
1189{
1190 return inode->i_link;
1191}
1192EXPORT_SYMBOL(simple_get_link);
1193
1194const struct inode_operations simple_symlink_inode_operations = {
1195 .get_link = simple_get_link,
1196};
1197EXPORT_SYMBOL(simple_symlink_inode_operations);
1198
1199
1200
1201
1202static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1203{
1204 return ERR_PTR(-ENOENT);
1205}
1206
1207static int empty_dir_getattr(const struct path *path, struct kstat *stat,
1208 u32 request_mask, unsigned int query_flags)
1209{
1210 struct inode *inode = d_inode(path->dentry);
1211 generic_fillattr(inode, stat);
1212 return 0;
1213}
1214
1215static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr)
1216{
1217 return -EPERM;
1218}
1219
1220static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size)
1221{
1222 return -EOPNOTSUPP;
1223}
1224
1225static const struct inode_operations empty_dir_inode_operations = {
1226 .lookup = empty_dir_lookup,
1227 .permission = generic_permission,
1228 .setattr = empty_dir_setattr,
1229 .getattr = empty_dir_getattr,
1230 .listxattr = empty_dir_listxattr,
1231};
1232
1233static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence)
1234{
1235
1236 return generic_file_llseek_size(file, offset, whence, 2, 2);
1237}
1238
1239static int empty_dir_readdir(struct file *file, struct dir_context *ctx)
1240{
1241 dir_emit_dots(file, ctx);
1242 return 0;
1243}
1244
1245static const struct file_operations empty_dir_operations = {
1246 .llseek = empty_dir_llseek,
1247 .read = generic_read_dir,
1248 .iterate_shared = empty_dir_readdir,
1249 .fsync = noop_fsync,
1250};
1251
1252
1253void make_empty_dir_inode(struct inode *inode)
1254{
1255 set_nlink(inode, 2);
1256 inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
1257 inode->i_uid = GLOBAL_ROOT_UID;
1258 inode->i_gid = GLOBAL_ROOT_GID;
1259 inode->i_rdev = 0;
1260 inode->i_size = 0;
1261 inode->i_blkbits = PAGE_SHIFT;
1262 inode->i_blocks = 0;
1263
1264 inode->i_op = &empty_dir_inode_operations;
1265 inode->i_opflags &= ~IOP_XATTR;
1266 inode->i_fop = &empty_dir_operations;
1267}
1268
1269bool is_empty_dir_inode(struct inode *inode)
1270{
1271 return (inode->i_fop == &empty_dir_operations) &&
1272 (inode->i_op == &empty_dir_inode_operations);
1273}
1274