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