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TOMOYO Linux Cross Reference
Linux/fs/overlayfs/file.c

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  * Copyright (C) 2017 Red Hat, Inc.
  4  */
  5 
  6 #include <linux/cred.h>
  7 #include <linux/file.h>
  8 #include <linux/mount.h>
  9 #include <linux/xattr.h>
 10 #include <linux/uio.h>
 11 #include <linux/uaccess.h>
 12 #include <linux/splice.h>
 13 #include <linux/security.h>
 14 #include <linux/mm.h>
 15 #include <linux/fs.h>
 16 #include "overlayfs.h"
 17 
 18 struct ovl_aio_req {
 19         struct kiocb iocb;
 20         struct kiocb *orig_iocb;
 21         struct fd fd;
 22 };
 23 
 24 static struct kmem_cache *ovl_aio_request_cachep;
 25 
 26 static char ovl_whatisit(struct inode *inode, struct inode *realinode)
 27 {
 28         if (realinode != ovl_inode_upper(inode))
 29                 return 'l';
 30         if (ovl_has_upperdata(inode))
 31                 return 'u';
 32         else
 33                 return 'm';
 34 }
 35 
 36 /* No atime modificaton nor notify on underlying */
 37 #define OVL_OPEN_FLAGS (O_NOATIME | FMODE_NONOTIFY)
 38 
 39 static struct file *ovl_open_realfile(const struct file *file,
 40                                       struct inode *realinode)
 41 {
 42         struct inode *inode = file_inode(file);
 43         struct file *realfile;
 44         const struct cred *old_cred;
 45         int flags = file->f_flags | OVL_OPEN_FLAGS;
 46         int acc_mode = ACC_MODE(flags);
 47         int err;
 48 
 49         if (flags & O_APPEND)
 50                 acc_mode |= MAY_APPEND;
 51 
 52         old_cred = ovl_override_creds(inode->i_sb);
 53         err = inode_permission(realinode, MAY_OPEN | acc_mode);
 54         if (err) {
 55                 realfile = ERR_PTR(err);
 56         } else if (!inode_owner_or_capable(realinode)) {
 57                 realfile = ERR_PTR(-EPERM);
 58         } else {
 59                 realfile = open_with_fake_path(&file->f_path, flags, realinode,
 60                                                current_cred());
 61         }
 62         revert_creds(old_cred);
 63 
 64         pr_debug("open(%p[%pD2/%c], 0%o) -> (%p, 0%o)\n",
 65                  file, file, ovl_whatisit(inode, realinode), file->f_flags,
 66                  realfile, IS_ERR(realfile) ? 0 : realfile->f_flags);
 67 
 68         return realfile;
 69 }
 70 
 71 #define OVL_SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT)
 72 
 73 static int ovl_change_flags(struct file *file, unsigned int flags)
 74 {
 75         struct inode *inode = file_inode(file);
 76         int err;
 77 
 78         flags |= OVL_OPEN_FLAGS;
 79 
 80         /* If some flag changed that cannot be changed then something's amiss */
 81         if (WARN_ON((file->f_flags ^ flags) & ~OVL_SETFL_MASK))
 82                 return -EIO;
 83 
 84         flags &= OVL_SETFL_MASK;
 85 
 86         if (((flags ^ file->f_flags) & O_APPEND) && IS_APPEND(inode))
 87                 return -EPERM;
 88 
 89         if (flags & O_DIRECT) {
 90                 if (!file->f_mapping->a_ops ||
 91                     !file->f_mapping->a_ops->direct_IO)
 92                         return -EINVAL;
 93         }
 94 
 95         if (file->f_op->check_flags) {
 96                 err = file->f_op->check_flags(flags);
 97                 if (err)
 98                         return err;
 99         }
100 
101         spin_lock(&file->f_lock);
102         file->f_flags = (file->f_flags & ~OVL_SETFL_MASK) | flags;
103         spin_unlock(&file->f_lock);
104 
105         return 0;
106 }
107 
108 static int ovl_real_fdget_meta(const struct file *file, struct fd *real,
109                                bool allow_meta)
110 {
111         struct inode *inode = file_inode(file);
112         struct inode *realinode;
113 
114         real->flags = 0;
115         real->file = file->private_data;
116 
117         if (allow_meta)
118                 realinode = ovl_inode_real(inode);
119         else
120                 realinode = ovl_inode_realdata(inode);
121 
122         /* Has it been copied up since we'd opened it? */
123         if (unlikely(file_inode(real->file) != realinode)) {
124                 real->flags = FDPUT_FPUT;
125                 real->file = ovl_open_realfile(file, realinode);
126 
127                 return PTR_ERR_OR_ZERO(real->file);
128         }
129 
130         /* Did the flags change since open? */
131         if (unlikely((file->f_flags ^ real->file->f_flags) & ~OVL_OPEN_FLAGS))
132                 return ovl_change_flags(real->file, file->f_flags);
133 
134         return 0;
135 }
136 
137 static int ovl_real_fdget(const struct file *file, struct fd *real)
138 {
139         return ovl_real_fdget_meta(file, real, false);
140 }
141 
142 static int ovl_open(struct inode *inode, struct file *file)
143 {
144         struct file *realfile;
145         int err;
146 
147         err = ovl_maybe_copy_up(file_dentry(file), file->f_flags);
148         if (err)
149                 return err;
150 
151         /* No longer need these flags, so don't pass them on to underlying fs */
152         file->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
153 
154         realfile = ovl_open_realfile(file, ovl_inode_realdata(inode));
155         if (IS_ERR(realfile))
156                 return PTR_ERR(realfile);
157 
158         file->private_data = realfile;
159 
160         return 0;
161 }
162 
163 static int ovl_release(struct inode *inode, struct file *file)
164 {
165         fput(file->private_data);
166 
167         return 0;
168 }
169 
170 static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)
171 {
172         struct inode *inode = file_inode(file);
173         struct fd real;
174         const struct cred *old_cred;
175         loff_t ret;
176 
177         /*
178          * The two special cases below do not need to involve real fs,
179          * so we can optimizing concurrent callers.
180          */
181         if (offset == 0) {
182                 if (whence == SEEK_CUR)
183                         return file->f_pos;
184 
185                 if (whence == SEEK_SET)
186                         return vfs_setpos(file, 0, 0);
187         }
188 
189         ret = ovl_real_fdget(file, &real);
190         if (ret)
191                 return ret;
192 
193         /*
194          * Overlay file f_pos is the master copy that is preserved
195          * through copy up and modified on read/write, but only real
196          * fs knows how to SEEK_HOLE/SEEK_DATA and real fs may impose
197          * limitations that are more strict than ->s_maxbytes for specific
198          * files, so we use the real file to perform seeks.
199          */
200         ovl_inode_lock(inode);
201         real.file->f_pos = file->f_pos;
202 
203         old_cred = ovl_override_creds(inode->i_sb);
204         ret = vfs_llseek(real.file, offset, whence);
205         revert_creds(old_cred);
206 
207         file->f_pos = real.file->f_pos;
208         ovl_inode_unlock(inode);
209 
210         fdput(real);
211 
212         return ret;
213 }
214 
215 static void ovl_file_accessed(struct file *file)
216 {
217         struct inode *inode, *upperinode;
218 
219         if (file->f_flags & O_NOATIME)
220                 return;
221 
222         inode = file_inode(file);
223         upperinode = ovl_inode_upper(inode);
224 
225         if (!upperinode)
226                 return;
227 
228         if ((!timespec64_equal(&inode->i_mtime, &upperinode->i_mtime) ||
229              !timespec64_equal(&inode->i_ctime, &upperinode->i_ctime))) {
230                 inode->i_mtime = upperinode->i_mtime;
231                 inode->i_ctime = upperinode->i_ctime;
232         }
233 
234         touch_atime(&file->f_path);
235 }
236 
237 static rwf_t ovl_iocb_to_rwf(int ifl)
238 {
239         rwf_t flags = 0;
240 
241         if (ifl & IOCB_NOWAIT)
242                 flags |= RWF_NOWAIT;
243         if (ifl & IOCB_HIPRI)
244                 flags |= RWF_HIPRI;
245         if (ifl & IOCB_DSYNC)
246                 flags |= RWF_DSYNC;
247         if (ifl & IOCB_SYNC)
248                 flags |= RWF_SYNC;
249 
250         return flags;
251 }
252 
253 static void ovl_aio_cleanup_handler(struct ovl_aio_req *aio_req)
254 {
255         struct kiocb *iocb = &aio_req->iocb;
256         struct kiocb *orig_iocb = aio_req->orig_iocb;
257 
258         if (iocb->ki_flags & IOCB_WRITE) {
259                 struct inode *inode = file_inode(orig_iocb->ki_filp);
260 
261                 /* Actually acquired in ovl_write_iter() */
262                 __sb_writers_acquired(file_inode(iocb->ki_filp)->i_sb,
263                                       SB_FREEZE_WRITE);
264                 file_end_write(iocb->ki_filp);
265                 ovl_copyattr(ovl_inode_real(inode), inode);
266         }
267 
268         orig_iocb->ki_pos = iocb->ki_pos;
269         fdput(aio_req->fd);
270         kmem_cache_free(ovl_aio_request_cachep, aio_req);
271 }
272 
273 static void ovl_aio_rw_complete(struct kiocb *iocb, long res, long res2)
274 {
275         struct ovl_aio_req *aio_req = container_of(iocb,
276                                                    struct ovl_aio_req, iocb);
277         struct kiocb *orig_iocb = aio_req->orig_iocb;
278 
279         ovl_aio_cleanup_handler(aio_req);
280         orig_iocb->ki_complete(orig_iocb, res, res2);
281 }
282 
283 static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)
284 {
285         struct file *file = iocb->ki_filp;
286         struct fd real;
287         const struct cred *old_cred;
288         ssize_t ret;
289 
290         if (!iov_iter_count(iter))
291                 return 0;
292 
293         ret = ovl_real_fdget(file, &real);
294         if (ret)
295                 return ret;
296 
297         old_cred = ovl_override_creds(file_inode(file)->i_sb);
298         if (is_sync_kiocb(iocb)) {
299                 ret = vfs_iter_read(real.file, iter, &iocb->ki_pos,
300                                     ovl_iocb_to_rwf(iocb->ki_flags));
301         } else {
302                 struct ovl_aio_req *aio_req;
303 
304                 ret = -ENOMEM;
305                 aio_req = kmem_cache_zalloc(ovl_aio_request_cachep, GFP_KERNEL);
306                 if (!aio_req)
307                         goto out;
308 
309                 aio_req->fd = real;
310                 real.flags = 0;
311                 aio_req->orig_iocb = iocb;
312                 kiocb_clone(&aio_req->iocb, iocb, real.file);
313                 aio_req->iocb.ki_complete = ovl_aio_rw_complete;
314                 ret = vfs_iocb_iter_read(real.file, &aio_req->iocb, iter);
315                 if (ret != -EIOCBQUEUED)
316                         ovl_aio_cleanup_handler(aio_req);
317         }
318 out:
319         revert_creds(old_cred);
320         ovl_file_accessed(file);
321 
322         fdput(real);
323 
324         return ret;
325 }
326 
327 static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
328 {
329         struct file *file = iocb->ki_filp;
330         struct inode *inode = file_inode(file);
331         struct fd real;
332         const struct cred *old_cred;
333         ssize_t ret;
334 
335         if (!iov_iter_count(iter))
336                 return 0;
337 
338         inode_lock(inode);
339         /* Update mode */
340         ovl_copyattr(ovl_inode_real(inode), inode);
341         ret = file_remove_privs(file);
342         if (ret)
343                 goto out_unlock;
344 
345         ret = ovl_real_fdget(file, &real);
346         if (ret)
347                 goto out_unlock;
348 
349         old_cred = ovl_override_creds(file_inode(file)->i_sb);
350         if (is_sync_kiocb(iocb)) {
351                 file_start_write(real.file);
352                 ret = vfs_iter_write(real.file, iter, &iocb->ki_pos,
353                                      ovl_iocb_to_rwf(iocb->ki_flags));
354                 file_end_write(real.file);
355                 /* Update size */
356                 ovl_copyattr(ovl_inode_real(inode), inode);
357         } else {
358                 struct ovl_aio_req *aio_req;
359 
360                 ret = -ENOMEM;
361                 aio_req = kmem_cache_zalloc(ovl_aio_request_cachep, GFP_KERNEL);
362                 if (!aio_req)
363                         goto out;
364 
365                 file_start_write(real.file);
366                 /* Pacify lockdep, same trick as done in aio_write() */
367                 __sb_writers_release(file_inode(real.file)->i_sb,
368                                      SB_FREEZE_WRITE);
369                 aio_req->fd = real;
370                 real.flags = 0;
371                 aio_req->orig_iocb = iocb;
372                 kiocb_clone(&aio_req->iocb, iocb, real.file);
373                 aio_req->iocb.ki_complete = ovl_aio_rw_complete;
374                 ret = vfs_iocb_iter_write(real.file, &aio_req->iocb, iter);
375                 if (ret != -EIOCBQUEUED)
376                         ovl_aio_cleanup_handler(aio_req);
377         }
378 out:
379         revert_creds(old_cred);
380         fdput(real);
381 
382 out_unlock:
383         inode_unlock(inode);
384 
385         return ret;
386 }
387 
388 static ssize_t ovl_splice_read(struct file *in, loff_t *ppos,
389                          struct pipe_inode_info *pipe, size_t len,
390                          unsigned int flags)
391 {
392         ssize_t ret;
393         struct fd real;
394         const struct cred *old_cred;
395 
396         ret = ovl_real_fdget(in, &real);
397         if (ret)
398                 return ret;
399 
400         old_cred = ovl_override_creds(file_inode(in)->i_sb);
401         ret = generic_file_splice_read(real.file, ppos, pipe, len, flags);
402         revert_creds(old_cred);
403 
404         ovl_file_accessed(in);
405         fdput(real);
406         return ret;
407 }
408 
409 static ssize_t
410 ovl_splice_write(struct pipe_inode_info *pipe, struct file *out,
411                           loff_t *ppos, size_t len, unsigned int flags)
412 {
413         struct fd real;
414         const struct cred *old_cred;
415         ssize_t ret;
416 
417         ret = ovl_real_fdget(out, &real);
418         if (ret)
419                 return ret;
420 
421         old_cred = ovl_override_creds(file_inode(out)->i_sb);
422         ret = iter_file_splice_write(pipe, real.file, ppos, len, flags);
423         revert_creds(old_cred);
424 
425         ovl_file_accessed(out);
426         fdput(real);
427         return ret;
428 }
429 
430 static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
431 {
432         struct fd real;
433         const struct cred *old_cred;
434         int ret;
435 
436         ret = ovl_real_fdget_meta(file, &real, !datasync);
437         if (ret)
438                 return ret;
439 
440         /* Don't sync lower file for fear of receiving EROFS error */
441         if (file_inode(real.file) == ovl_inode_upper(file_inode(file))) {
442                 old_cred = ovl_override_creds(file_inode(file)->i_sb);
443                 ret = vfs_fsync_range(real.file, start, end, datasync);
444                 revert_creds(old_cred);
445         }
446 
447         fdput(real);
448 
449         return ret;
450 }
451 
452 static int ovl_mmap(struct file *file, struct vm_area_struct *vma)
453 {
454         struct file *realfile = file->private_data;
455         const struct cred *old_cred;
456         int ret;
457 
458         if (!realfile->f_op->mmap)
459                 return -ENODEV;
460 
461         if (WARN_ON(file != vma->vm_file))
462                 return -EIO;
463 
464         vma->vm_file = get_file(realfile);
465 
466         old_cred = ovl_override_creds(file_inode(file)->i_sb);
467         ret = call_mmap(vma->vm_file, vma);
468         revert_creds(old_cred);
469 
470         if (ret) {
471                 /* Drop reference count from new vm_file value */
472                 fput(realfile);
473         } else {
474                 /* Drop reference count from previous vm_file value */
475                 fput(file);
476         }
477 
478         ovl_file_accessed(file);
479 
480         return ret;
481 }
482 
483 static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
484 {
485         struct inode *inode = file_inode(file);
486         struct fd real;
487         const struct cred *old_cred;
488         int ret;
489 
490         ret = ovl_real_fdget(file, &real);
491         if (ret)
492                 return ret;
493 
494         old_cred = ovl_override_creds(file_inode(file)->i_sb);
495         ret = vfs_fallocate(real.file, mode, offset, len);
496         revert_creds(old_cred);
497 
498         /* Update size */
499         ovl_copyattr(ovl_inode_real(inode), inode);
500 
501         fdput(real);
502 
503         return ret;
504 }
505 
506 static int ovl_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
507 {
508         struct fd real;
509         const struct cred *old_cred;
510         int ret;
511 
512         ret = ovl_real_fdget(file, &real);
513         if (ret)
514                 return ret;
515 
516         old_cred = ovl_override_creds(file_inode(file)->i_sb);
517         ret = vfs_fadvise(real.file, offset, len, advice);
518         revert_creds(old_cred);
519 
520         fdput(real);
521 
522         return ret;
523 }
524 
525 static long ovl_real_ioctl(struct file *file, unsigned int cmd,
526                            unsigned long arg)
527 {
528         struct fd real;
529         const struct cred *old_cred;
530         long ret;
531 
532         ret = ovl_real_fdget(file, &real);
533         if (ret)
534                 return ret;
535 
536         old_cred = ovl_override_creds(file_inode(file)->i_sb);
537         ret = security_file_ioctl(real.file, cmd, arg);
538         if (!ret)
539                 ret = vfs_ioctl(real.file, cmd, arg);
540         revert_creds(old_cred);
541 
542         fdput(real);
543 
544         return ret;
545 }
546 
547 static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
548                                 unsigned long arg, unsigned int iflags)
549 {
550         long ret;
551         struct inode *inode = file_inode(file);
552         unsigned int old_iflags;
553 
554         if (!inode_owner_or_capable(inode))
555                 return -EACCES;
556 
557         ret = mnt_want_write_file(file);
558         if (ret)
559                 return ret;
560 
561         inode_lock(inode);
562 
563         /* Check the capability before cred override */
564         ret = -EPERM;
565         old_iflags = READ_ONCE(inode->i_flags);
566         if (((iflags ^ old_iflags) & (S_APPEND | S_IMMUTABLE)) &&
567             !capable(CAP_LINUX_IMMUTABLE))
568                 goto unlock;
569 
570         ret = ovl_maybe_copy_up(file_dentry(file), O_WRONLY);
571         if (ret)
572                 goto unlock;
573 
574         ret = ovl_real_ioctl(file, cmd, arg);
575 
576         ovl_copyflags(ovl_inode_real(inode), inode);
577 unlock:
578         inode_unlock(inode);
579 
580         mnt_drop_write_file(file);
581 
582         return ret;
583 
584 }
585 
586 static unsigned int ovl_fsflags_to_iflags(unsigned int flags)
587 {
588         unsigned int iflags = 0;
589 
590         if (flags & FS_SYNC_FL)
591                 iflags |= S_SYNC;
592         if (flags & FS_APPEND_FL)
593                 iflags |= S_APPEND;
594         if (flags & FS_IMMUTABLE_FL)
595                 iflags |= S_IMMUTABLE;
596         if (flags & FS_NOATIME_FL)
597                 iflags |= S_NOATIME;
598 
599         return iflags;
600 }
601 
602 static long ovl_ioctl_set_fsflags(struct file *file, unsigned int cmd,
603                                   unsigned long arg)
604 {
605         unsigned int flags;
606 
607         if (get_user(flags, (int __user *) arg))
608                 return -EFAULT;
609 
610         return ovl_ioctl_set_flags(file, cmd, arg,
611                                    ovl_fsflags_to_iflags(flags));
612 }
613 
614 static unsigned int ovl_fsxflags_to_iflags(unsigned int xflags)
615 {
616         unsigned int iflags = 0;
617 
618         if (xflags & FS_XFLAG_SYNC)
619                 iflags |= S_SYNC;
620         if (xflags & FS_XFLAG_APPEND)
621                 iflags |= S_APPEND;
622         if (xflags & FS_XFLAG_IMMUTABLE)
623                 iflags |= S_IMMUTABLE;
624         if (xflags & FS_XFLAG_NOATIME)
625                 iflags |= S_NOATIME;
626 
627         return iflags;
628 }
629 
630 static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd,
631                                    unsigned long arg)
632 {
633         struct fsxattr fa;
634 
635         memset(&fa, 0, sizeof(fa));
636         if (copy_from_user(&fa, (void __user *) arg, sizeof(fa)))
637                 return -EFAULT;
638 
639         return ovl_ioctl_set_flags(file, cmd, arg,
640                                    ovl_fsxflags_to_iflags(fa.fsx_xflags));
641 }
642 
643 static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
644 {
645         long ret;
646 
647         switch (cmd) {
648         case FS_IOC_GETFLAGS:
649         case FS_IOC_FSGETXATTR:
650                 ret = ovl_real_ioctl(file, cmd, arg);
651                 break;
652 
653         case FS_IOC_SETFLAGS:
654                 ret = ovl_ioctl_set_fsflags(file, cmd, arg);
655                 break;
656 
657         case FS_IOC_FSSETXATTR:
658                 ret = ovl_ioctl_set_fsxflags(file, cmd, arg);
659                 break;
660 
661         default:
662                 ret = -ENOTTY;
663         }
664 
665         return ret;
666 }
667 
668 static long ovl_compat_ioctl(struct file *file, unsigned int cmd,
669                              unsigned long arg)
670 {
671         switch (cmd) {
672         case FS_IOC32_GETFLAGS:
673                 cmd = FS_IOC_GETFLAGS;
674                 break;
675 
676         case FS_IOC32_SETFLAGS:
677                 cmd = FS_IOC_SETFLAGS;
678                 break;
679 
680         default:
681                 return -ENOIOCTLCMD;
682         }
683 
684         return ovl_ioctl(file, cmd, arg);
685 }
686 
687 enum ovl_copyop {
688         OVL_COPY,
689         OVL_CLONE,
690         OVL_DEDUPE,
691 };
692 
693 static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in,
694                             struct file *file_out, loff_t pos_out,
695                             loff_t len, unsigned int flags, enum ovl_copyop op)
696 {
697         struct inode *inode_out = file_inode(file_out);
698         struct fd real_in, real_out;
699         const struct cred *old_cred;
700         loff_t ret;
701 
702         ret = ovl_real_fdget(file_out, &real_out);
703         if (ret)
704                 return ret;
705 
706         ret = ovl_real_fdget(file_in, &real_in);
707         if (ret) {
708                 fdput(real_out);
709                 return ret;
710         }
711 
712         old_cred = ovl_override_creds(file_inode(file_out)->i_sb);
713         switch (op) {
714         case OVL_COPY:
715                 ret = vfs_copy_file_range(real_in.file, pos_in,
716                                           real_out.file, pos_out, len, flags);
717                 break;
718 
719         case OVL_CLONE:
720                 ret = vfs_clone_file_range(real_in.file, pos_in,
721                                            real_out.file, pos_out, len, flags);
722                 break;
723 
724         case OVL_DEDUPE:
725                 ret = vfs_dedupe_file_range_one(real_in.file, pos_in,
726                                                 real_out.file, pos_out, len,
727                                                 flags);
728                 break;
729         }
730         revert_creds(old_cred);
731 
732         /* Update size */
733         ovl_copyattr(ovl_inode_real(inode_out), inode_out);
734 
735         fdput(real_in);
736         fdput(real_out);
737 
738         return ret;
739 }
740 
741 static ssize_t ovl_copy_file_range(struct file *file_in, loff_t pos_in,
742                                    struct file *file_out, loff_t pos_out,
743                                    size_t len, unsigned int flags)
744 {
745         return ovl_copyfile(file_in, pos_in, file_out, pos_out, len, flags,
746                             OVL_COPY);
747 }
748 
749 static loff_t ovl_remap_file_range(struct file *file_in, loff_t pos_in,
750                                    struct file *file_out, loff_t pos_out,
751                                    loff_t len, unsigned int remap_flags)
752 {
753         enum ovl_copyop op;
754 
755         if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
756                 return -EINVAL;
757 
758         if (remap_flags & REMAP_FILE_DEDUP)
759                 op = OVL_DEDUPE;
760         else
761                 op = OVL_CLONE;
762 
763         /*
764          * Don't copy up because of a dedupe request, this wouldn't make sense
765          * most of the time (data would be duplicated instead of deduplicated).
766          */
767         if (op == OVL_DEDUPE &&
768             (!ovl_inode_upper(file_inode(file_in)) ||
769              !ovl_inode_upper(file_inode(file_out))))
770                 return -EPERM;
771 
772         return ovl_copyfile(file_in, pos_in, file_out, pos_out, len,
773                             remap_flags, op);
774 }
775 
776 const struct file_operations ovl_file_operations = {
777         .open           = ovl_open,
778         .release        = ovl_release,
779         .llseek         = ovl_llseek,
780         .read_iter      = ovl_read_iter,
781         .write_iter     = ovl_write_iter,
782         .fsync          = ovl_fsync,
783         .mmap           = ovl_mmap,
784         .fallocate      = ovl_fallocate,
785         .fadvise        = ovl_fadvise,
786         .unlocked_ioctl = ovl_ioctl,
787         .compat_ioctl   = ovl_compat_ioctl,
788         .splice_read    = ovl_splice_read,
789         .splice_write   = ovl_splice_write,
790 
791         .copy_file_range        = ovl_copy_file_range,
792         .remap_file_range       = ovl_remap_file_range,
793 };
794 
795 int __init ovl_aio_request_cache_init(void)
796 {
797         ovl_aio_request_cachep = kmem_cache_create("ovl_aio_req",
798                                                    sizeof(struct ovl_aio_req),
799                                                    0, SLAB_HWCACHE_ALIGN, NULL);
800         if (!ovl_aio_request_cachep)
801                 return -ENOMEM;
802 
803         return 0;
804 }
805 
806 void ovl_aio_request_cache_destroy(void)
807 {
808         kmem_cache_destroy(ovl_aio_request_cachep);
809 }
810 

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