fs/overlayfs/file.c

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