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/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 }