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 #include "../internal.h"        /* for sb_init_dio_done_wq */
  19
  20 struct ovl_aio_req {
  21         struct kiocb iocb;
  22         refcount_t ref;
  23         struct kiocb *orig_iocb;
  24         /* used for aio completion */
  25         struct work_struct work;
  26         long res;
  27 };
  28
  29 static struct kmem_cache *ovl_aio_request_cachep;
  30
  31 static char ovl_whatisit(struct inode *inode, struct inode *realinode)
  32 {
  33         if (realinode != ovl_inode_upper(inode))
  34                 return 'l';
  35         if (ovl_has_upperdata(inode))
  36                 return 'u';
  37         else
  38                 return 'm';
  39 }
  40
  41 /* No atime modification on underlying */
  42 #define OVL_OPEN_FLAGS (O_NOATIME)
  43
  44 static struct file *ovl_open_realfile(const struct file *file,
  45                                       const struct path *realpath)
  46 {
  47         struct inode *realinode = d_inode(realpath->dentry);
  48         struct inode *inode = file_inode(file);
  49         struct mnt_idmap *real_idmap;
  50         struct file *realfile;
  51         const struct cred *old_cred;
  52         int flags = file->f_flags | OVL_OPEN_FLAGS;
  53         int acc_mode = ACC_MODE(flags);
  54         int err;
  55
  56         if (flags & O_APPEND)
  57                 acc_mode |= MAY_APPEND;
  58
  59         old_cred = ovl_override_creds(inode->i_sb);
  60         real_idmap = mnt_idmap(realpath->mnt);
  61         err = inode_permission(real_idmap, realinode, MAY_OPEN | acc_mode);
  62         if (err) {
  63                 realfile = ERR_PTR(err);
  64         } else {
  65                 if (!inode_owner_or_capable(real_idmap, realinode))
  66                         flags &= ~O_NOATIME;
  67
  68                 realfile = backing_file_open(&file->f_path, flags, realpath,
  69                                              current_cred());
  70         }
  71         revert_creds(old_cred);
  72
  73         pr_debug("open(%p[%pD2/%c], 0%o) -> (%p, 0%o)\n",
  74                  file, file, ovl_whatisit(inode, realinode), file->f_flags,
  75                  realfile, IS_ERR(realfile) ? 0 : realfile->f_flags);
  76
  77         return realfile;
  78 }
  79
  80 #define OVL_SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT)
  81
  82 static int ovl_change_flags(struct file *file, unsigned int flags)
  83 {
  84         struct inode *inode = file_inode(file);
  85         int err;
  86
  87         flags &= OVL_SETFL_MASK;
  88
  89         if (((flags ^ file->f_flags) & O_APPEND) && IS_APPEND(inode))
  90                 return -EPERM;
  91
  92         if ((flags & O_DIRECT) && !(file->f_mode & FMODE_CAN_ODIRECT))
  93                 return -EINVAL;
  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         file->f_iocb_flags = iocb_flags(file);
 104         spin_unlock(&file->f_lock);
 105
 106         return 0;
 107 }
 108
 109 static int ovl_real_fdget_meta(const struct file *file, struct fd *real,
 110                                bool allow_meta)
 111 {
 112         struct dentry *dentry = file_dentry(file);
 113         struct path realpath;
 114         int err;
 115
 116         real->flags = 0;
 117         real->file = file->private_data;
 118
 119         if (allow_meta) {
 120                 ovl_path_real(dentry, &realpath);
 121         } else {
 122                 /* lazy lookup and verify of lowerdata */
 123                 err = ovl_verify_lowerdata(dentry);
 124                 if (err)
 125                         return err;
 126
 127                 ovl_path_realdata(dentry, &realpath);
 128         }
 129         if (!realpath.dentry)
 130                 return -EIO;
 131
 132         /* Has it been copied up since we'd opened it? */
 133         if (unlikely(file_inode(real->file) != d_inode(realpath.dentry))) {
 134                 real->flags = FDPUT_FPUT;
 135                 real->file = ovl_open_realfile(file, &realpath);
 136
 137                 return PTR_ERR_OR_ZERO(real->file);
 138         }
 139
 140         /* Did the flags change since open? */
 141         if (unlikely((file->f_flags ^ real->file->f_flags) & ~OVL_OPEN_FLAGS))
 142                 return ovl_change_flags(real->file, file->f_flags);
 143
 144         return 0;
 145 }
 146
 147 static int ovl_real_fdget(const struct file *file, struct fd *real)
 148 {
 149         if (d_is_dir(file_dentry(file))) {
 150                 real->flags = 0;
 151                 real->file = ovl_dir_real_file(file, false);
 152
 153                 return PTR_ERR_OR_ZERO(real->file);
 154         }
 155
 156         return ovl_real_fdget_meta(file, real, false);
 157 }
 158
 159 static int ovl_open(struct inode *inode, struct file *file)
 160 {
 161         struct dentry *dentry = file_dentry(file);
 162         struct file *realfile;
 163         struct path realpath;
 164         int err;
 165
 166         /* lazy lookup and verify lowerdata */
 167         err = ovl_verify_lowerdata(dentry);
 168         if (err)
 169                 return err;
 170
 171         err = ovl_maybe_copy_up(dentry, file->f_flags);
 172         if (err)
 173                 return err;
 174
 175         /* No longer need these flags, so don't pass them on to underlying fs */
 176         file->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
 177
 178         ovl_path_realdata(dentry, &realpath);
 179         if (!realpath.dentry)
 180                 return -EIO;
 181
 182         realfile = ovl_open_realfile(file, &realpath);
 183         if (IS_ERR(realfile))
 184                 return PTR_ERR(realfile);
 185
 186         file->private_data = realfile;
 187
 188         return 0;
 189 }
 190
 191 static int ovl_release(struct inode *inode, struct file *file)
 192 {
 193         fput(file->private_data);
 194
 195         return 0;
 196 }
 197
 198 static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)
 199 {
 200         struct inode *inode = file_inode(file);
 201         struct fd real;
 202         const struct cred *old_cred;
 203         loff_t ret;
 204
 205         /*
 206          * The two special cases below do not need to involve real fs,
 207          * so we can optimizing concurrent callers.
 208          */
 209         if (offset == 0) {
 210                 if (whence == SEEK_CUR)
 211                         return file->f_pos;
 212
 213                 if (whence == SEEK_SET)
 214                         return vfs_setpos(file, 0, 0);
 215         }
 216
 217         ret = ovl_real_fdget(file, &real);
 218         if (ret)
 219                 return ret;
 220
 221         /*
 222          * Overlay file f_pos is the master copy that is preserved
 223          * through copy up and modified on read/write, but only real
 224          * fs knows how to SEEK_HOLE/SEEK_DATA and real fs may impose
 225          * limitations that are more strict than ->s_maxbytes for specific
 226          * files, so we use the real file to perform seeks.
 227          */
 228         ovl_inode_lock(inode);
 229         real.file->f_pos = file->f_pos;
 230
 231         old_cred = ovl_override_creds(inode->i_sb);
 232         ret = vfs_llseek(real.file, offset, whence);
 233         revert_creds(old_cred);
 234
 235         file->f_pos = real.file->f_pos;
 236         ovl_inode_unlock(inode);
 237
 238         fdput(real);
 239
 240         return ret;
 241 }
 242
 243 static void ovl_file_modified(struct file *file)
 244 {
 245         /* Update size/mtime */
 246         ovl_copyattr(file_inode(file));
 247 }
 248
 249 static void ovl_file_accessed(struct file *file)
 250 {
 251         struct inode *inode, *upperinode;
 252         struct timespec64 ctime, uctime;
 253         struct timespec64 mtime, umtime;
 254
 255         if (file->f_flags & O_NOATIME)
 256                 return;
 257
 258         inode = file_inode(file);
 259         upperinode = ovl_inode_upper(inode);
 260
 261         if (!upperinode)
 262                 return;
 263
 264         ctime = inode_get_ctime(inode);
 265         uctime = inode_get_ctime(upperinode);
 266         mtime = inode_get_mtime(inode);
 267         umtime = inode_get_mtime(upperinode);
 268         if ((!timespec64_equal(&mtime, &umtime)) ||
 269              !timespec64_equal(&ctime, &uctime)) {
 270                 inode_set_mtime_to_ts(inode, inode_get_mtime(upperinode));
 271                 inode_set_ctime_to_ts(inode, uctime);
 272         }
 273
 274         touch_atime(&file->f_path);
 275 }
 276
 277 #define OVL_IOCB_MASK \
 278         (IOCB_NOWAIT | IOCB_HIPRI | IOCB_DSYNC | IOCB_SYNC | IOCB_APPEND)
 279
 280 static rwf_t iocb_to_rw_flags(int flags)
 281 {
 282         return (__force rwf_t)(flags & OVL_IOCB_MASK);
 283 }
 284
 285 static inline void ovl_aio_put(struct ovl_aio_req *aio_req)
 286 {
 287         if (refcount_dec_and_test(&aio_req->ref)) {
 288                 fput(aio_req->iocb.ki_filp);
 289                 kmem_cache_free(ovl_aio_request_cachep, aio_req);
 290         }
 291 }
 292
 293 static void ovl_aio_cleanup_handler(struct ovl_aio_req *aio_req)
 294 {
 295         struct kiocb *iocb = &aio_req->iocb;
 296         struct kiocb *orig_iocb = aio_req->orig_iocb;
 297
 298         if (iocb->ki_flags & IOCB_WRITE) {
 299                 kiocb_end_write(iocb);
 300                 ovl_file_modified(orig_iocb->ki_filp);
 301         }
 302
 303         orig_iocb->ki_pos = iocb->ki_pos;
 304         ovl_aio_put(aio_req);
 305 }
 306
 307 static void ovl_aio_rw_complete(struct kiocb *iocb, long res)
 308 {
 309         struct ovl_aio_req *aio_req = container_of(iocb,
 310                                                    struct ovl_aio_req, iocb);
 311         struct kiocb *orig_iocb = aio_req->orig_iocb;
 312
 313         ovl_aio_cleanup_handler(aio_req);
 314         orig_iocb->ki_complete(orig_iocb, res);
 315 }
 316
 317 static void ovl_aio_complete_work(struct work_struct *work)
 318 {
 319         struct ovl_aio_req *aio_req = container_of(work,
 320                                                    struct ovl_aio_req, work);
 321
 322         ovl_aio_rw_complete(&aio_req->iocb, aio_req->res);
 323 }
 324
 325 static void ovl_aio_queue_completion(struct kiocb *iocb, long res)
 326 {
 327         struct ovl_aio_req *aio_req = container_of(iocb,
 328                                                    struct ovl_aio_req, iocb);
 329         struct kiocb *orig_iocb = aio_req->orig_iocb;
 330
 331         /*
 332          * Punt to a work queue to serialize updates of mtime/size.
 333          */
 334         aio_req->res = res;
 335         INIT_WORK(&aio_req->work, ovl_aio_complete_work);
 336         queue_work(file_inode(orig_iocb->ki_filp)->i_sb->s_dio_done_wq,
 337                    &aio_req->work);
 338 }
 339
 340 static int ovl_init_aio_done_wq(struct super_block *sb)
 341 {
 342         if (sb->s_dio_done_wq)
 343                 return 0;
 344
 345         return sb_init_dio_done_wq(sb);
 346 }
 347
 348 static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 349 {
 350         struct file *file = iocb->ki_filp;
 351         struct fd real;
 352         const struct cred *old_cred;
 353         ssize_t ret;
 354
 355         if (!iov_iter_count(iter))
 356                 return 0;
 357
 358         ret = ovl_real_fdget(file, &real);
 359         if (ret)
 360                 return ret;
 361
 362         ret = -EINVAL;
 363         if (iocb->ki_flags & IOCB_DIRECT &&
 364             !(real.file->f_mode & FMODE_CAN_ODIRECT))
 365                 goto out_fdput;
 366
 367         old_cred = ovl_override_creds(file_inode(file)->i_sb);
 368         if (is_sync_kiocb(iocb)) {
 369                 rwf_t rwf = iocb_to_rw_flags(iocb->ki_flags);
 370
 371                 ret = vfs_iter_read(real.file, iter, &iocb->ki_pos, rwf);
 372         } else {
 373                 struct ovl_aio_req *aio_req;
 374
 375                 ret = -ENOMEM;
 376                 aio_req = kmem_cache_zalloc(ovl_aio_request_cachep, GFP_KERNEL);
 377                 if (!aio_req)
 378                         goto out;
 379
 380                 aio_req->orig_iocb = iocb;
 381                 kiocb_clone(&aio_req->iocb, iocb, get_file(real.file));
 382                 aio_req->iocb.ki_complete = ovl_aio_rw_complete;
 383                 refcount_set(&aio_req->ref, 2);
 384                 ret = vfs_iocb_iter_read(real.file, &aio_req->iocb, iter);
 385                 ovl_aio_put(aio_req);
 386                 if (ret != -EIOCBQUEUED)
 387                         ovl_aio_cleanup_handler(aio_req);
 388         }
 389 out:
 390         revert_creds(old_cred);
 391         ovl_file_accessed(file);
 392 out_fdput:
 393         fdput(real);
 394
 395         return ret;
 396 }
 397
 398 static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
 399 {
 400         struct file *file = iocb->ki_filp;
 401         struct inode *inode = file_inode(file);
 402         struct fd real;
 403         const struct cred *old_cred;
 404         ssize_t ret;
 405         int ifl = iocb->ki_flags;
 406
 407         if (!iov_iter_count(iter))
 408                 return 0;
 409
 410         inode_lock(inode);
 411         /* Update mode */
 412         ovl_copyattr(inode);
 413         ret = file_remove_privs(file);
 414         if (ret)
 415                 goto out_unlock;
 416
 417         ret = ovl_real_fdget(file, &real);
 418         if (ret)
 419                 goto out_unlock;
 420
 421         ret = -EINVAL;
 422         if (iocb->ki_flags & IOCB_DIRECT &&
 423             !(real.file->f_mode & FMODE_CAN_ODIRECT))
 424                 goto out_fdput;
 425
 426         if (!ovl_should_sync(OVL_FS(inode->i_sb)))
 427                 ifl &= ~(IOCB_DSYNC | IOCB_SYNC);
 428
 429         /*
 430          * Overlayfs doesn't support deferred completions, don't copy
 431          * this property in case it is set by the issuer.
 432          */
 433         ifl &= ~IOCB_DIO_CALLER_COMP;
 434
 435         old_cred = ovl_override_creds(file_inode(file)->i_sb);
 436         if (is_sync_kiocb(iocb)) {
 437                 rwf_t rwf = iocb_to_rw_flags(ifl);
 438
 439                 file_start_write(real.file);
 440                 ret = vfs_iter_write(real.file, iter, &iocb->ki_pos, rwf);
 441                 file_end_write(real.file);
 442                 /* Update size */
 443                 ovl_file_modified(file);
 444         } else {
 445                 struct ovl_aio_req *aio_req;
 446
 447                 ret = ovl_init_aio_done_wq(inode->i_sb);
 448                 if (ret)
 449                         goto out;
 450
 451                 ret = -ENOMEM;
 452                 aio_req = kmem_cache_zalloc(ovl_aio_request_cachep, GFP_KERNEL);
 453                 if (!aio_req)
 454                         goto out;
 455
 456                 aio_req->orig_iocb = iocb;
 457                 kiocb_clone(&aio_req->iocb, iocb, get_file(real.file));
 458                 aio_req->iocb.ki_flags = ifl;
 459                 aio_req->iocb.ki_complete = ovl_aio_queue_completion;
 460                 refcount_set(&aio_req->ref, 2);
 461                 kiocb_start_write(&aio_req->iocb);
 462                 ret = vfs_iocb_iter_write(real.file, &aio_req->iocb, iter);
 463                 ovl_aio_put(aio_req);
 464                 if (ret != -EIOCBQUEUED)
 465                         ovl_aio_cleanup_handler(aio_req);
 466         }
 467 out:
 468         revert_creds(old_cred);
 469 out_fdput:
 470         fdput(real);
 471
 472 out_unlock:
 473         inode_unlock(inode);
 474
 475         return ret;
 476 }
 477
 478 static ssize_t ovl_splice_read(struct file *in, loff_t *ppos,
 479                                struct pipe_inode_info *pipe, size_t len,
 480                                unsigned int flags)
 481 {
 482         const struct cred *old_cred;
 483         struct fd real;
 484         ssize_t ret;
 485
 486         ret = ovl_real_fdget(in, &real);
 487         if (ret)
 488                 return ret;
 489
 490         old_cred = ovl_override_creds(file_inode(in)->i_sb);
 491         ret = vfs_splice_read(real.file, ppos, pipe, len, flags);
 492         revert_creds(old_cred);
 493         ovl_file_accessed(in);
 494
 495         fdput(real);
 496         return ret;
 497 }
 498
 499 /*
 500  * Calling iter_file_splice_write() directly from overlay's f_op may deadlock
 501  * due to lock order inversion between pipe->mutex in iter_file_splice_write()
 502  * and file_start_write(real.file) in ovl_write_iter().
 503  *
 504  * So do everything ovl_write_iter() does and call iter_file_splice_write() on
 505  * the real file.
 506  */
 507 static ssize_t ovl_splice_write(struct pipe_inode_info *pipe, struct file *out,
 508                                 loff_t *ppos, size_t len, unsigned int flags)
 509 {
 510         struct fd real;
 511         const struct cred *old_cred;
 512         struct inode *inode = file_inode(out);
 513         ssize_t ret;
 514
 515         inode_lock(inode);
 516         /* Update mode */
 517         ovl_copyattr(inode);
 518         ret = file_remove_privs(out);
 519         if (ret)
 520                 goto out_unlock;
 521
 522         ret = ovl_real_fdget(out, &real);
 523         if (ret)
 524                 goto out_unlock;
 525
 526         old_cred = ovl_override_creds(inode->i_sb);
 527         file_start_write(real.file);
 528
 529         ret = iter_file_splice_write(pipe, real.file, ppos, len, flags);
 530
 531         file_end_write(real.file);
 532         /* Update size */
 533         ovl_file_modified(out);
 534         revert_creds(old_cred);
 535         fdput(real);
 536
 537 out_unlock:
 538         inode_unlock(inode);
 539
 540         return ret;
 541 }
 542
 543 static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 544 {
 545         struct fd real;
 546         const struct cred *old_cred;
 547         int ret;
 548
 549         ret = ovl_sync_status(OVL_FS(file_inode(file)->i_sb));
 550         if (ret <= 0)
 551                 return ret;
 552
 553         ret = ovl_real_fdget_meta(file, &real, !datasync);
 554         if (ret)
 555                 return ret;
 556
 557         /* Don't sync lower file for fear of receiving EROFS error */
 558         if (file_inode(real.file) == ovl_inode_upper(file_inode(file))) {
 559                 old_cred = ovl_override_creds(file_inode(file)->i_sb);
 560                 ret = vfs_fsync_range(real.file, start, end, datasync);
 561                 revert_creds(old_cred);
 562         }
 563
 564         fdput(real);
 565
 566         return ret;
 567 }
 568
 569 static int ovl_mmap(struct file *file, struct vm_area_struct *vma)
 570 {
 571         struct file *realfile = file->private_data;
 572         const struct cred *old_cred;
 573         int ret;
 574
 575         if (!realfile->f_op->mmap)
 576                 return -ENODEV;
 577
 578         if (WARN_ON(file != vma->vm_file))
 579                 return -EIO;
 580
 581         vma_set_file(vma, realfile);
 582
 583         old_cred = ovl_override_creds(file_inode(file)->i_sb);
 584         ret = call_mmap(vma->vm_file, vma);
 585         revert_creds(old_cred);
 586         ovl_file_accessed(file);
 587
 588         return ret;
 589 }
 590
 591 static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 592 {
 593         struct inode *inode = file_inode(file);
 594         struct fd real;
 595         const struct cred *old_cred;
 596         int ret;
 597
 598         inode_lock(inode);
 599         /* Update mode */
 600         ovl_copyattr(inode);
 601         ret = file_remove_privs(file);
 602         if (ret)
 603                 goto out_unlock;
 604
 605         ret = ovl_real_fdget(file, &real);
 606         if (ret)
 607                 goto out_unlock;
 608
 609         old_cred = ovl_override_creds(file_inode(file)->i_sb);
 610         ret = vfs_fallocate(real.file, mode, offset, len);
 611         revert_creds(old_cred);
 612
 613         /* Update size */
 614         ovl_file_modified(file);
 615
 616         fdput(real);
 617
 618 out_unlock:
 619         inode_unlock(inode);
 620
 621         return ret;
 622 }
 623
 624 static int ovl_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
 625 {
 626         struct fd real;
 627         const struct cred *old_cred;
 628         int ret;
 629
 630         ret = ovl_real_fdget(file, &real);
 631         if (ret)
 632                 return ret;
 633
 634         old_cred = ovl_override_creds(file_inode(file)->i_sb);
 635         ret = vfs_fadvise(real.file, offset, len, advice);
 636         revert_creds(old_cred);
 637
 638         fdput(real);
 639
 640         return ret;
 641 }
 642
 643 enum ovl_copyop {
 644         OVL_COPY,
 645         OVL_CLONE,
 646         OVL_DEDUPE,
 647 };
 648
 649 static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in,
 650                             struct file *file_out, loff_t pos_out,
 651                             loff_t len, unsigned int flags, enum ovl_copyop op)
 652 {
 653         struct inode *inode_out = file_inode(file_out);
 654         struct fd real_in, real_out;
 655         const struct cred *old_cred;
 656         loff_t ret;
 657
 658         inode_lock(inode_out);
 659         if (op != OVL_DEDUPE) {
 660                 /* Update mode */
 661                 ovl_copyattr(inode_out);
 662                 ret = file_remove_privs(file_out);
 663                 if (ret)
 664                         goto out_unlock;
 665         }
 666
 667         ret = ovl_real_fdget(file_out, &real_out);
 668         if (ret)
 669                 goto out_unlock;
 670
 671         ret = ovl_real_fdget(file_in, &real_in);
 672         if (ret) {
 673                 fdput(real_out);
 674                 goto out_unlock;
 675         }
 676
 677         old_cred = ovl_override_creds(file_inode(file_out)->i_sb);
 678         switch (op) {
 679         case OVL_COPY:
 680                 ret = vfs_copy_file_range(real_in.file, pos_in,
 681                                           real_out.file, pos_out, len, flags);
 682                 break;
 683
 684         case OVL_CLONE:
 685                 ret = vfs_clone_file_range(real_in.file, pos_in,
 686                                            real_out.file, pos_out, len, flags);
 687                 break;
 688
 689         case OVL_DEDUPE:
 690                 ret = vfs_dedupe_file_range_one(real_in.file, pos_in,
 691                                                 real_out.file, pos_out, len,
 692                                                 flags);
 693                 break;
 694         }
 695         revert_creds(old_cred);
 696
 697         /* Update size */
 698         ovl_file_modified(file_out);
 699
 700         fdput(real_in);
 701         fdput(real_out);
 702
 703 out_unlock:
 704         inode_unlock(inode_out);
 705
 706         return ret;
 707 }
 708
 709 static ssize_t ovl_copy_file_range(struct file *file_in, loff_t pos_in,
 710                                    struct file *file_out, loff_t pos_out,
 711                                    size_t len, unsigned int flags)
 712 {
 713         return ovl_copyfile(file_in, pos_in, file_out, pos_out, len, flags,
 714                             OVL_COPY);
 715 }
 716
 717 static loff_t ovl_remap_file_range(struct file *file_in, loff_t pos_in,
 718                                    struct file *file_out, loff_t pos_out,
 719                                    loff_t len, unsigned int remap_flags)
 720 {
 721         enum ovl_copyop op;
 722
 723         if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
 724                 return -EINVAL;
 725
 726         if (remap_flags & REMAP_FILE_DEDUP)
 727                 op = OVL_DEDUPE;
 728         else
 729                 op = OVL_CLONE;
 730
 731         /*
 732          * Don't copy up because of a dedupe request, this wouldn't make sense
 733          * most of the time (data would be duplicated instead of deduplicated).
 734          */
 735         if (op == OVL_DEDUPE &&
 736             (!ovl_inode_upper(file_inode(file_in)) ||
 737              !ovl_inode_upper(file_inode(file_out))))
 738                 return -EPERM;
 739
 740         return ovl_copyfile(file_in, pos_in, file_out, pos_out, len,
 741                             remap_flags, op);
 742 }
 743
 744 static int ovl_flush(struct file *file, fl_owner_t id)
 745 {
 746         struct fd real;
 747         const struct cred *old_cred;
 748         int err;
 749
 750         err = ovl_real_fdget(file, &real);
 751         if (err)
 752                 return err;
 753
 754         if (real.file->f_op->flush) {
 755                 old_cred = ovl_override_creds(file_inode(file)->i_sb);
 756                 err = real.file->f_op->flush(real.file, id);
 757                 revert_creds(old_cred);
 758         }
 759         fdput(real);
 760
 761         return err;
 762 }
 763
 764 const struct file_operations ovl_file_operations = {
 765         .open           = ovl_open,
 766         .release        = ovl_release,
 767         .llseek         = ovl_llseek,
 768         .read_iter      = ovl_read_iter,
 769         .write_iter     = ovl_write_iter,
 770         .fsync          = ovl_fsync,
 771         .mmap           = ovl_mmap,
 772         .fallocate      = ovl_fallocate,
 773         .fadvise        = ovl_fadvise,
 774         .flush          = ovl_flush,
 775         .splice_read    = ovl_splice_read,
 776         .splice_write   = ovl_splice_write,
 777
 778         .copy_file_range        = ovl_copy_file_range,
 779         .remap_file_range       = ovl_remap_file_range,
 780 };
 781
 782 int __init ovl_aio_request_cache_init(void)
 783 {
 784         ovl_aio_request_cachep = kmem_cache_create("ovl_aio_req",
 785                                                    sizeof(struct ovl_aio_req),
 786                                                    0, SLAB_HWCACHE_ALIGN, NULL);
 787         if (!ovl_aio_request_cachep)
 788                 return -ENOMEM;
 789
 790         return 0;
 791 }
 792
 793 void ovl_aio_request_cache_destroy(void)
 794 {
 795         kmem_cache_destroy(ovl_aio_request_cachep);
 796 }