1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org> 13 * Copyright (c) 2013, 2014 The FreeBSD Foundation 14 * 15 * Portions of this software were developed by Konstantin Belousov 16 * under sponsorship from the FreeBSD Foundation. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 3. Neither the name of the University nor the names of its contributors 27 * may be used to endorse or promote products derived from this software 28 * without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 */ 42 43 #include <sys/cdefs.h> 44 #include "opt_hwpmc_hooks.h" 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/disk.h> 49 #include <sys/fail.h> 50 #include <sys/fcntl.h> 51 #include <sys/file.h> 52 #include <sys/kdb.h> 53 #include <sys/ktr.h> 54 #include <sys/stat.h> 55 #include <sys/priv.h> 56 #include <sys/proc.h> 57 #include <sys/limits.h> 58 #include <sys/lock.h> 59 #include <sys/mman.h> 60 #include <sys/mount.h> 61 #include <sys/mutex.h> 62 #include <sys/namei.h> 63 #include <sys/vnode.h> 64 #include <sys/dirent.h> 65 #include <sys/bio.h> 66 #include <sys/buf.h> 67 #include <sys/filio.h> 68 #include <sys/resourcevar.h> 69 #include <sys/rwlock.h> 70 #include <sys/prng.h> 71 #include <sys/sx.h> 72 #include <sys/sleepqueue.h> 73 #include <sys/sysctl.h> 74 #include <sys/ttycom.h> 75 #include <sys/conf.h> 76 #include <sys/syslog.h> 77 #include <sys/unistd.h> 78 #include <sys/user.h> 79 #include <sys/ktrace.h> 80 81 #include <security/audit/audit.h> 82 #include <security/mac/mac_framework.h> 83 84 #include <vm/vm.h> 85 #include <vm/vm_extern.h> 86 #include <vm/pmap.h> 87 #include <vm/vm_map.h> 88 #include <vm/vm_object.h> 89 #include <vm/vm_page.h> 90 #include <vm/vm_pager.h> 91 #include <vm/vnode_pager.h> 92 93 #ifdef HWPMC_HOOKS 94 #include <sys/pmckern.h> 95 #endif 96 97 static fo_rdwr_t vn_read; 98 static fo_rdwr_t vn_write; 99 static fo_rdwr_t vn_io_fault; 100 static fo_truncate_t vn_truncate; 101 static fo_ioctl_t vn_ioctl; 102 static fo_poll_t vn_poll; 103 static fo_kqfilter_t vn_kqfilter; 104 static fo_close_t vn_closefile; 105 static fo_mmap_t vn_mmap; 106 static fo_fallocate_t vn_fallocate; 107 static fo_fspacectl_t vn_fspacectl; 108 109 struct fileops vnops = { 110 .fo_read = vn_io_fault, 111 .fo_write = vn_io_fault, 112 .fo_truncate = vn_truncate, 113 .fo_ioctl = vn_ioctl, 114 .fo_poll = vn_poll, 115 .fo_kqfilter = vn_kqfilter, 116 .fo_stat = vn_statfile, 117 .fo_close = vn_closefile, 118 .fo_chmod = vn_chmod, 119 .fo_chown = vn_chown, 120 .fo_sendfile = vn_sendfile, 121 .fo_seek = vn_seek, 122 .fo_fill_kinfo = vn_fill_kinfo, 123 .fo_mmap = vn_mmap, 124 .fo_fallocate = vn_fallocate, 125 .fo_fspacectl = vn_fspacectl, 126 .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE 127 }; 128 129 const u_int io_hold_cnt = 16; 130 static int vn_io_fault_enable = 1; 131 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RWTUN, 132 &vn_io_fault_enable, 0, "Enable vn_io_fault lock avoidance"); 133 static int vn_io_fault_prefault = 0; 134 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_prefault, CTLFLAG_RWTUN, 135 &vn_io_fault_prefault, 0, "Enable vn_io_fault prefaulting"); 136 static int vn_io_pgcache_read_enable = 1; 137 SYSCTL_INT(_debug, OID_AUTO, vn_io_pgcache_read_enable, CTLFLAG_RWTUN, 138 &vn_io_pgcache_read_enable, 0, 139 "Enable copying from page cache for reads, avoiding fs"); 140 static u_long vn_io_faults_cnt; 141 SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD, 142 &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers"); 143 144 static int vfs_allow_read_dir = 0; 145 SYSCTL_INT(_security_bsd, OID_AUTO, allow_read_dir, CTLFLAG_RW, 146 &vfs_allow_read_dir, 0, 147 "Enable read(2) of directory by root for filesystems that support it"); 148 149 /* 150 * Returns true if vn_io_fault mode of handling the i/o request should 151 * be used. 152 */ 153 static bool 154 do_vn_io_fault(struct vnode *vp, struct uio *uio) 155 { 156 struct mount *mp; 157 158 return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG && 159 (mp = vp->v_mount) != NULL && 160 (mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable); 161 } 162 163 /* 164 * Structure used to pass arguments to vn_io_fault1(), to do either 165 * file- or vnode-based I/O calls. 166 */ 167 struct vn_io_fault_args { 168 enum { 169 VN_IO_FAULT_FOP, 170 VN_IO_FAULT_VOP 171 } kind; 172 struct ucred *cred; 173 int flags; 174 union { 175 struct fop_args_tag { 176 struct file *fp; 177 fo_rdwr_t *doio; 178 } fop_args; 179 struct vop_args_tag { 180 struct vnode *vp; 181 } vop_args; 182 } args; 183 }; 184 185 static int vn_io_fault1(struct vnode *vp, struct uio *uio, 186 struct vn_io_fault_args *args, struct thread *td); 187 188 int 189 vn_open(struct nameidata *ndp, int *flagp, int cmode, struct file *fp) 190 { 191 struct thread *td = curthread; 192 193 return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp)); 194 } 195 196 static uint64_t 197 open2nameif(int fmode, u_int vn_open_flags) 198 { 199 uint64_t res; 200 201 res = ISOPEN | LOCKLEAF; 202 if ((fmode & O_RESOLVE_BENEATH) != 0) 203 res |= RBENEATH; 204 if ((fmode & O_EMPTY_PATH) != 0) 205 res |= EMPTYPATH; 206 if ((fmode & FREAD) != 0) 207 res |= OPENREAD; 208 if ((fmode & FWRITE) != 0) 209 res |= OPENWRITE; 210 if ((vn_open_flags & VN_OPEN_NOAUDIT) == 0) 211 res |= AUDITVNODE1; 212 if ((vn_open_flags & VN_OPEN_NOCAPCHECK) != 0) 213 res |= NOCAPCHECK; 214 if ((vn_open_flags & VN_OPEN_WANTIOCTLCAPS) != 0) 215 res |= WANTIOCTLCAPS; 216 return (res); 217 } 218 219 /* 220 * Common code for vnode open operations via a name lookup. 221 * Lookup the vnode and invoke VOP_CREATE if needed. 222 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 223 * 224 * Note that this does NOT free nameidata for the successful case, 225 * due to the NDINIT being done elsewhere. 226 */ 227 int 228 vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags, 229 struct ucred *cred, struct file *fp) 230 { 231 struct vnode *vp; 232 struct mount *mp; 233 struct vattr vat; 234 struct vattr *vap = &vat; 235 int fmode, error; 236 bool first_open; 237 238 restart: 239 first_open = false; 240 fmode = *flagp; 241 if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT | 242 O_EXCL | O_DIRECTORY) || 243 (fmode & (O_CREAT | O_EMPTY_PATH)) == (O_CREAT | O_EMPTY_PATH)) 244 return (EINVAL); 245 else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) { 246 ndp->ni_cnd.cn_nameiop = CREATE; 247 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags); 248 /* 249 * Set NOCACHE to avoid flushing the cache when 250 * rolling in many files at once. 251 * 252 * Set NC_KEEPPOSENTRY to keep positive entries if they already 253 * exist despite NOCACHE. 254 */ 255 ndp->ni_cnd.cn_flags |= LOCKPARENT | NOCACHE | NC_KEEPPOSENTRY; 256 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 257 ndp->ni_cnd.cn_flags |= FOLLOW; 258 if ((vn_open_flags & VN_OPEN_INVFS) == 0) 259 bwillwrite(); 260 if ((error = namei(ndp)) != 0) 261 return (error); 262 if (ndp->ni_vp == NULL) { 263 VATTR_NULL(vap); 264 vap->va_type = VREG; 265 vap->va_mode = cmode; 266 if (fmode & O_EXCL) 267 vap->va_vaflags |= VA_EXCLUSIVE; 268 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) { 269 NDFREE_PNBUF(ndp); 270 vput(ndp->ni_dvp); 271 if ((error = vn_start_write(NULL, &mp, 272 V_XSLEEP | V_PCATCH)) != 0) 273 return (error); 274 NDREINIT(ndp); 275 goto restart; 276 } 277 if ((vn_open_flags & VN_OPEN_NAMECACHE) != 0) 278 ndp->ni_cnd.cn_flags |= MAKEENTRY; 279 #ifdef MAC 280 error = mac_vnode_check_create(cred, ndp->ni_dvp, 281 &ndp->ni_cnd, vap); 282 if (error == 0) 283 #endif 284 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 285 &ndp->ni_cnd, vap); 286 vp = ndp->ni_vp; 287 if (error == 0 && (fmode & O_EXCL) != 0 && 288 (fmode & (O_EXLOCK | O_SHLOCK)) != 0) { 289 VI_LOCK(vp); 290 vp->v_iflag |= VI_FOPENING; 291 VI_UNLOCK(vp); 292 first_open = true; 293 } 294 VOP_VPUT_PAIR(ndp->ni_dvp, error == 0 ? &vp : NULL, 295 false); 296 vn_finished_write(mp); 297 if (error) { 298 NDFREE_PNBUF(ndp); 299 if (error == ERELOOKUP) { 300 NDREINIT(ndp); 301 goto restart; 302 } 303 return (error); 304 } 305 fmode &= ~O_TRUNC; 306 } else { 307 if (ndp->ni_dvp == ndp->ni_vp) 308 vrele(ndp->ni_dvp); 309 else 310 vput(ndp->ni_dvp); 311 ndp->ni_dvp = NULL; 312 vp = ndp->ni_vp; 313 if (fmode & O_EXCL) { 314 error = EEXIST; 315 goto bad; 316 } 317 if (vp->v_type == VDIR) { 318 error = EISDIR; 319 goto bad; 320 } 321 fmode &= ~O_CREAT; 322 } 323 } else { 324 ndp->ni_cnd.cn_nameiop = LOOKUP; 325 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags); 326 ndp->ni_cnd.cn_flags |= (fmode & O_NOFOLLOW) != 0 ? NOFOLLOW : 327 FOLLOW; 328 if ((fmode & FWRITE) == 0) 329 ndp->ni_cnd.cn_flags |= LOCKSHARED; 330 if ((error = namei(ndp)) != 0) 331 return (error); 332 vp = ndp->ni_vp; 333 } 334 error = vn_open_vnode(vp, fmode, cred, curthread, fp); 335 if (first_open) { 336 VI_LOCK(vp); 337 vp->v_iflag &= ~VI_FOPENING; 338 wakeup(vp); 339 VI_UNLOCK(vp); 340 } 341 if (error) 342 goto bad; 343 *flagp = fmode; 344 return (0); 345 bad: 346 NDFREE_PNBUF(ndp); 347 vput(vp); 348 *flagp = fmode; 349 ndp->ni_vp = NULL; 350 return (error); 351 } 352 353 static int 354 vn_open_vnode_advlock(struct vnode *vp, int fmode, struct file *fp) 355 { 356 struct flock lf; 357 int error, lock_flags, type; 358 359 ASSERT_VOP_LOCKED(vp, "vn_open_vnode_advlock"); 360 if ((fmode & (O_EXLOCK | O_SHLOCK)) == 0) 361 return (0); 362 KASSERT(fp != NULL, ("open with flock requires fp")); 363 if (fp->f_type != DTYPE_NONE && fp->f_type != DTYPE_VNODE) 364 return (EOPNOTSUPP); 365 366 lock_flags = VOP_ISLOCKED(vp); 367 VOP_UNLOCK(vp); 368 369 lf.l_whence = SEEK_SET; 370 lf.l_start = 0; 371 lf.l_len = 0; 372 lf.l_type = (fmode & O_EXLOCK) != 0 ? F_WRLCK : F_RDLCK; 373 type = F_FLOCK; 374 if ((fmode & FNONBLOCK) == 0) 375 type |= F_WAIT; 376 if ((fmode & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL)) 377 type |= F_FIRSTOPEN; 378 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type); 379 if (error == 0) 380 fp->f_flag |= FHASLOCK; 381 382 vn_lock(vp, lock_flags | LK_RETRY); 383 return (error); 384 } 385 386 /* 387 * Common code for vnode open operations once a vnode is located. 388 * Check permissions, and call the VOP_OPEN routine. 389 */ 390 int 391 vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred, 392 struct thread *td, struct file *fp) 393 { 394 accmode_t accmode; 395 int error; 396 397 if (vp->v_type == VLNK) { 398 if ((fmode & O_PATH) == 0 || (fmode & FEXEC) != 0) 399 return (EMLINK); 400 } 401 if (vp->v_type != VDIR && fmode & O_DIRECTORY) 402 return (ENOTDIR); 403 404 accmode = 0; 405 if ((fmode & O_PATH) == 0) { 406 if (vp->v_type == VSOCK) 407 return (EOPNOTSUPP); 408 if ((fmode & (FWRITE | O_TRUNC)) != 0) { 409 if (vp->v_type == VDIR) 410 return (EISDIR); 411 accmode |= VWRITE; 412 } 413 if ((fmode & FREAD) != 0) 414 accmode |= VREAD; 415 if ((fmode & O_APPEND) && (fmode & FWRITE)) 416 accmode |= VAPPEND; 417 #ifdef MAC 418 if ((fmode & O_CREAT) != 0) 419 accmode |= VCREAT; 420 #endif 421 } 422 if ((fmode & FEXEC) != 0) 423 accmode |= VEXEC; 424 #ifdef MAC 425 if ((fmode & O_VERIFY) != 0) 426 accmode |= VVERIFY; 427 error = mac_vnode_check_open(cred, vp, accmode); 428 if (error != 0) 429 return (error); 430 431 accmode &= ~(VCREAT | VVERIFY); 432 #endif 433 if ((fmode & O_CREAT) == 0 && accmode != 0) { 434 error = VOP_ACCESS(vp, accmode, cred, td); 435 if (error != 0) 436 return (error); 437 } 438 if ((fmode & O_PATH) != 0) { 439 if (vp->v_type != VFIFO && vp->v_type != VSOCK && 440 VOP_ACCESS(vp, VREAD, cred, td) == 0) 441 fp->f_flag |= FKQALLOWED; 442 return (0); 443 } 444 445 if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 446 vn_lock(vp, LK_UPGRADE | LK_RETRY); 447 error = VOP_OPEN(vp, fmode, cred, td, fp); 448 if (error != 0) 449 return (error); 450 451 error = vn_open_vnode_advlock(vp, fmode, fp); 452 if (error == 0 && (fmode & FWRITE) != 0) { 453 error = VOP_ADD_WRITECOUNT(vp, 1); 454 if (error == 0) { 455 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 456 __func__, vp, vp->v_writecount); 457 } 458 } 459 460 /* 461 * Error from advlock or VOP_ADD_WRITECOUNT() still requires 462 * calling VOP_CLOSE() to pair with earlier VOP_OPEN(). 463 */ 464 if (error != 0) { 465 if (fp != NULL) { 466 /* 467 * Arrange the call by having fdrop() to use 468 * vn_closefile(). This is to satisfy 469 * filesystems like devfs or tmpfs, which 470 * override fo_close(). 471 */ 472 fp->f_flag |= FOPENFAILED; 473 fp->f_vnode = vp; 474 if (fp->f_ops == &badfileops) { 475 fp->f_type = DTYPE_VNODE; 476 fp->f_ops = &vnops; 477 } 478 vref(vp); 479 } else { 480 /* 481 * If there is no fp, due to kernel-mode open, 482 * we can call VOP_CLOSE() now. 483 */ 484 if ((vp->v_type == VFIFO || 485 !MNT_EXTENDED_SHARED(vp->v_mount)) && 486 VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 487 vn_lock(vp, LK_UPGRADE | LK_RETRY); 488 (void)VOP_CLOSE(vp, fmode & (FREAD | FWRITE | FEXEC), 489 cred, td); 490 } 491 } 492 493 ASSERT_VOP_LOCKED(vp, "vn_open_vnode"); 494 return (error); 495 496 } 497 498 /* 499 * Check for write permissions on the specified vnode. 500 * Prototype text segments cannot be written. 501 * It is racy. 502 */ 503 int 504 vn_writechk(struct vnode *vp) 505 { 506 507 ASSERT_VOP_LOCKED(vp, "vn_writechk"); 508 /* 509 * If there's shared text associated with 510 * the vnode, try to free it up once. If 511 * we fail, we can't allow writing. 512 */ 513 if (VOP_IS_TEXT(vp)) 514 return (ETXTBSY); 515 516 return (0); 517 } 518 519 /* 520 * Vnode close call 521 */ 522 static int 523 vn_close1(struct vnode *vp, int flags, struct ucred *file_cred, 524 struct thread *td, bool keep_ref) 525 { 526 struct mount *mp; 527 int error, lock_flags; 528 529 lock_flags = vp->v_type != VFIFO && MNT_EXTENDED_SHARED(vp->v_mount) ? 530 LK_SHARED : LK_EXCLUSIVE; 531 532 vn_start_write(vp, &mp, V_WAIT); 533 vn_lock(vp, lock_flags | LK_RETRY); 534 AUDIT_ARG_VNODE1(vp); 535 if ((flags & (FWRITE | FOPENFAILED)) == FWRITE) { 536 VOP_ADD_WRITECOUNT_CHECKED(vp, -1); 537 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 538 __func__, vp, vp->v_writecount); 539 } 540 error = VOP_CLOSE(vp, flags, file_cred, td); 541 if (keep_ref) 542 VOP_UNLOCK(vp); 543 else 544 vput(vp); 545 vn_finished_write(mp); 546 return (error); 547 } 548 549 int 550 vn_close(struct vnode *vp, int flags, struct ucred *file_cred, 551 struct thread *td) 552 { 553 554 return (vn_close1(vp, flags, file_cred, td, false)); 555 } 556 557 /* 558 * Heuristic to detect sequential operation. 559 */ 560 static int 561 sequential_heuristic(struct uio *uio, struct file *fp) 562 { 563 enum uio_rw rw; 564 565 ASSERT_VOP_LOCKED(fp->f_vnode, __func__); 566 567 rw = uio->uio_rw; 568 if (fp->f_flag & FRDAHEAD) 569 return (fp->f_seqcount[rw] << IO_SEQSHIFT); 570 571 /* 572 * Offset 0 is handled specially. open() sets f_seqcount to 1 so 573 * that the first I/O is normally considered to be slightly 574 * sequential. Seeking to offset 0 doesn't change sequentiality 575 * unless previous seeks have reduced f_seqcount to 0, in which 576 * case offset 0 is not special. 577 */ 578 if ((uio->uio_offset == 0 && fp->f_seqcount[rw] > 0) || 579 uio->uio_offset == fp->f_nextoff[rw]) { 580 /* 581 * f_seqcount is in units of fixed-size blocks so that it 582 * depends mainly on the amount of sequential I/O and not 583 * much on the number of sequential I/O's. The fixed size 584 * of 16384 is hard-coded here since it is (not quite) just 585 * a magic size that works well here. This size is more 586 * closely related to the best I/O size for real disks than 587 * to any block size used by software. 588 */ 589 if (uio->uio_resid >= IO_SEQMAX * 16384) 590 fp->f_seqcount[rw] = IO_SEQMAX; 591 else { 592 fp->f_seqcount[rw] += howmany(uio->uio_resid, 16384); 593 if (fp->f_seqcount[rw] > IO_SEQMAX) 594 fp->f_seqcount[rw] = IO_SEQMAX; 595 } 596 return (fp->f_seqcount[rw] << IO_SEQSHIFT); 597 } 598 599 /* Not sequential. Quickly draw-down sequentiality. */ 600 if (fp->f_seqcount[rw] > 1) 601 fp->f_seqcount[rw] = 1; 602 else 603 fp->f_seqcount[rw] = 0; 604 return (0); 605 } 606 607 /* 608 * Package up an I/O request on a vnode into a uio and do it. 609 */ 610 int 611 vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset, 612 enum uio_seg segflg, int ioflg, struct ucred *active_cred, 613 struct ucred *file_cred, ssize_t *aresid, struct thread *td) 614 { 615 struct uio auio; 616 struct iovec aiov; 617 struct mount *mp; 618 struct ucred *cred; 619 void *rl_cookie; 620 struct vn_io_fault_args args; 621 int error, lock_flags; 622 623 if (offset < 0 && vp->v_type != VCHR) 624 return (EINVAL); 625 auio.uio_iov = &aiov; 626 auio.uio_iovcnt = 1; 627 aiov.iov_base = base; 628 aiov.iov_len = len; 629 auio.uio_resid = len; 630 auio.uio_offset = offset; 631 auio.uio_segflg = segflg; 632 auio.uio_rw = rw; 633 auio.uio_td = td; 634 error = 0; 635 636 if ((ioflg & IO_NODELOCKED) == 0) { 637 if ((ioflg & IO_RANGELOCKED) == 0) { 638 if (rw == UIO_READ) { 639 rl_cookie = vn_rangelock_rlock(vp, offset, 640 offset + len); 641 } else if ((ioflg & IO_APPEND) != 0) { 642 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 643 } else { 644 rl_cookie = vn_rangelock_wlock(vp, offset, 645 offset + len); 646 } 647 } else 648 rl_cookie = NULL; 649 mp = NULL; 650 if (rw == UIO_WRITE) { 651 if (vp->v_type != VCHR && 652 (error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH)) 653 != 0) 654 goto out; 655 lock_flags = vn_lktype_write(mp, vp); 656 } else 657 lock_flags = LK_SHARED; 658 vn_lock(vp, lock_flags | LK_RETRY); 659 } else 660 rl_cookie = NULL; 661 662 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 663 #ifdef MAC 664 if ((ioflg & IO_NOMACCHECK) == 0) { 665 if (rw == UIO_READ) 666 error = mac_vnode_check_read(active_cred, file_cred, 667 vp); 668 else 669 error = mac_vnode_check_write(active_cred, file_cred, 670 vp); 671 } 672 #endif 673 if (error == 0) { 674 if (file_cred != NULL) 675 cred = file_cred; 676 else 677 cred = active_cred; 678 if (do_vn_io_fault(vp, &auio)) { 679 args.kind = VN_IO_FAULT_VOP; 680 args.cred = cred; 681 args.flags = ioflg; 682 args.args.vop_args.vp = vp; 683 error = vn_io_fault1(vp, &auio, &args, td); 684 } else if (rw == UIO_READ) { 685 error = VOP_READ(vp, &auio, ioflg, cred); 686 } else /* if (rw == UIO_WRITE) */ { 687 error = VOP_WRITE(vp, &auio, ioflg, cred); 688 } 689 } 690 if (aresid) 691 *aresid = auio.uio_resid; 692 else 693 if (auio.uio_resid && error == 0) 694 error = EIO; 695 if ((ioflg & IO_NODELOCKED) == 0) { 696 VOP_UNLOCK(vp); 697 if (mp != NULL) 698 vn_finished_write(mp); 699 } 700 out: 701 if (rl_cookie != NULL) 702 vn_rangelock_unlock(vp, rl_cookie); 703 return (error); 704 } 705 706 /* 707 * Package up an I/O request on a vnode into a uio and do it. The I/O 708 * request is split up into smaller chunks and we try to avoid saturating 709 * the buffer cache while potentially holding a vnode locked, so we 710 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield() 711 * to give other processes a chance to lock the vnode (either other processes 712 * core'ing the same binary, or unrelated processes scanning the directory). 713 */ 714 int 715 vn_rdwr_inchunks(enum uio_rw rw, struct vnode *vp, void *base, size_t len, 716 off_t offset, enum uio_seg segflg, int ioflg, struct ucred *active_cred, 717 struct ucred *file_cred, size_t *aresid, struct thread *td) 718 { 719 int error = 0; 720 ssize_t iaresid; 721 722 do { 723 int chunk; 724 725 /* 726 * Force `offset' to a multiple of MAXBSIZE except possibly 727 * for the first chunk, so that filesystems only need to 728 * write full blocks except possibly for the first and last 729 * chunks. 730 */ 731 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE; 732 733 if (chunk > len) 734 chunk = len; 735 if (rw != UIO_READ && vp->v_type == VREG) 736 bwillwrite(); 737 iaresid = 0; 738 error = vn_rdwr(rw, vp, base, chunk, offset, segflg, 739 ioflg, active_cred, file_cred, &iaresid, td); 740 len -= chunk; /* aresid calc already includes length */ 741 if (error) 742 break; 743 offset += chunk; 744 base = (char *)base + chunk; 745 kern_yield(PRI_USER); 746 } while (len); 747 if (aresid) 748 *aresid = len + iaresid; 749 return (error); 750 } 751 752 #if OFF_MAX <= LONG_MAX 753 off_t 754 foffset_lock(struct file *fp, int flags) 755 { 756 volatile short *flagsp; 757 off_t res; 758 short state; 759 760 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 761 762 if ((flags & FOF_NOLOCK) != 0) 763 return (atomic_load_long(&fp->f_offset)); 764 765 /* 766 * According to McKusick the vn lock was protecting f_offset here. 767 * It is now protected by the FOFFSET_LOCKED flag. 768 */ 769 flagsp = &fp->f_vnread_flags; 770 if (atomic_cmpset_acq_16(flagsp, 0, FOFFSET_LOCKED)) 771 return (atomic_load_long(&fp->f_offset)); 772 773 sleepq_lock(&fp->f_vnread_flags); 774 state = atomic_load_16(flagsp); 775 for (;;) { 776 if ((state & FOFFSET_LOCKED) == 0) { 777 if (!atomic_fcmpset_acq_16(flagsp, &state, 778 FOFFSET_LOCKED)) 779 continue; 780 break; 781 } 782 if ((state & FOFFSET_LOCK_WAITING) == 0) { 783 if (!atomic_fcmpset_acq_16(flagsp, &state, 784 state | FOFFSET_LOCK_WAITING)) 785 continue; 786 } 787 DROP_GIANT(); 788 sleepq_add(&fp->f_vnread_flags, NULL, "vofflock", 0, 0); 789 sleepq_wait(&fp->f_vnread_flags, PUSER -1); 790 PICKUP_GIANT(); 791 sleepq_lock(&fp->f_vnread_flags); 792 state = atomic_load_16(flagsp); 793 } 794 res = atomic_load_long(&fp->f_offset); 795 sleepq_release(&fp->f_vnread_flags); 796 return (res); 797 } 798 799 void 800 foffset_unlock(struct file *fp, off_t val, int flags) 801 { 802 volatile short *flagsp; 803 short state; 804 805 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 806 807 if ((flags & FOF_NOUPDATE) == 0) 808 atomic_store_long(&fp->f_offset, val); 809 if ((flags & FOF_NEXTOFF_R) != 0) 810 fp->f_nextoff[UIO_READ] = val; 811 if ((flags & FOF_NEXTOFF_W) != 0) 812 fp->f_nextoff[UIO_WRITE] = val; 813 814 if ((flags & FOF_NOLOCK) != 0) 815 return; 816 817 flagsp = &fp->f_vnread_flags; 818 state = atomic_load_16(flagsp); 819 if ((state & FOFFSET_LOCK_WAITING) == 0 && 820 atomic_cmpset_rel_16(flagsp, state, 0)) 821 return; 822 823 sleepq_lock(&fp->f_vnread_flags); 824 MPASS((fp->f_vnread_flags & FOFFSET_LOCKED) != 0); 825 MPASS((fp->f_vnread_flags & FOFFSET_LOCK_WAITING) != 0); 826 fp->f_vnread_flags = 0; 827 sleepq_broadcast(&fp->f_vnread_flags, SLEEPQ_SLEEP, 0, 0); 828 sleepq_release(&fp->f_vnread_flags); 829 } 830 831 static off_t 832 foffset_read(struct file *fp) 833 { 834 835 return (atomic_load_long(&fp->f_offset)); 836 } 837 #else 838 off_t 839 foffset_lock(struct file *fp, int flags) 840 { 841 struct mtx *mtxp; 842 off_t res; 843 844 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 845 846 mtxp = mtx_pool_find(mtxpool_sleep, fp); 847 mtx_lock(mtxp); 848 if ((flags & FOF_NOLOCK) == 0) { 849 while (fp->f_vnread_flags & FOFFSET_LOCKED) { 850 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING; 851 msleep(&fp->f_vnread_flags, mtxp, PUSER -1, 852 "vofflock", 0); 853 } 854 fp->f_vnread_flags |= FOFFSET_LOCKED; 855 } 856 res = fp->f_offset; 857 mtx_unlock(mtxp); 858 return (res); 859 } 860 861 void 862 foffset_unlock(struct file *fp, off_t val, int flags) 863 { 864 struct mtx *mtxp; 865 866 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 867 868 mtxp = mtx_pool_find(mtxpool_sleep, fp); 869 mtx_lock(mtxp); 870 if ((flags & FOF_NOUPDATE) == 0) 871 fp->f_offset = val; 872 if ((flags & FOF_NEXTOFF_R) != 0) 873 fp->f_nextoff[UIO_READ] = val; 874 if ((flags & FOF_NEXTOFF_W) != 0) 875 fp->f_nextoff[UIO_WRITE] = val; 876 if ((flags & FOF_NOLOCK) == 0) { 877 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0, 878 ("Lost FOFFSET_LOCKED")); 879 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING) 880 wakeup(&fp->f_vnread_flags); 881 fp->f_vnread_flags = 0; 882 } 883 mtx_unlock(mtxp); 884 } 885 886 static off_t 887 foffset_read(struct file *fp) 888 { 889 890 return (foffset_lock(fp, FOF_NOLOCK)); 891 } 892 #endif 893 894 void 895 foffset_lock_uio(struct file *fp, struct uio *uio, int flags) 896 { 897 898 if ((flags & FOF_OFFSET) == 0) 899 uio->uio_offset = foffset_lock(fp, flags); 900 } 901 902 void 903 foffset_unlock_uio(struct file *fp, struct uio *uio, int flags) 904 { 905 906 if ((flags & FOF_OFFSET) == 0) 907 foffset_unlock(fp, uio->uio_offset, flags); 908 } 909 910 static int 911 get_advice(struct file *fp, struct uio *uio) 912 { 913 struct mtx *mtxp; 914 int ret; 915 916 ret = POSIX_FADV_NORMAL; 917 if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG) 918 return (ret); 919 920 mtxp = mtx_pool_find(mtxpool_sleep, fp); 921 mtx_lock(mtxp); 922 if (fp->f_advice != NULL && 923 uio->uio_offset >= fp->f_advice->fa_start && 924 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end) 925 ret = fp->f_advice->fa_advice; 926 mtx_unlock(mtxp); 927 return (ret); 928 } 929 930 static int 931 get_write_ioflag(struct file *fp) 932 { 933 int ioflag; 934 struct mount *mp; 935 struct vnode *vp; 936 937 ioflag = 0; 938 vp = fp->f_vnode; 939 mp = atomic_load_ptr(&vp->v_mount); 940 941 if ((fp->f_flag & O_DIRECT) != 0) 942 ioflag |= IO_DIRECT; 943 944 if ((fp->f_flag & O_FSYNC) != 0 || 945 (mp != NULL && (mp->mnt_flag & MNT_SYNCHRONOUS) != 0)) 946 ioflag |= IO_SYNC; 947 948 /* 949 * For O_DSYNC we set both IO_SYNC and IO_DATASYNC, so that VOP_WRITE() 950 * or VOP_DEALLOCATE() implementations that don't understand IO_DATASYNC 951 * fall back to full O_SYNC behavior. 952 */ 953 if ((fp->f_flag & O_DSYNC) != 0) 954 ioflag |= IO_SYNC | IO_DATASYNC; 955 956 return (ioflag); 957 } 958 959 int 960 vn_read_from_obj(struct vnode *vp, struct uio *uio) 961 { 962 vm_object_t obj; 963 vm_page_t ma[io_hold_cnt + 2]; 964 off_t off, vsz; 965 ssize_t resid; 966 int error, i, j; 967 968 MPASS(uio->uio_resid <= ptoa(io_hold_cnt + 2)); 969 obj = atomic_load_ptr(&vp->v_object); 970 if (obj == NULL) 971 return (EJUSTRETURN); 972 973 /* 974 * Depends on type stability of vm_objects. 975 */ 976 vm_object_pip_add(obj, 1); 977 if ((obj->flags & OBJ_DEAD) != 0) { 978 /* 979 * Note that object might be already reused from the 980 * vnode, and the OBJ_DEAD flag cleared. This is fine, 981 * we recheck for DOOMED vnode state after all pages 982 * are busied, and retract then. 983 * 984 * But we check for OBJ_DEAD to ensure that we do not 985 * busy pages while vm_object_terminate_pages() 986 * processes the queue. 987 */ 988 error = EJUSTRETURN; 989 goto out_pip; 990 } 991 992 resid = uio->uio_resid; 993 off = uio->uio_offset; 994 for (i = 0; resid > 0; i++) { 995 MPASS(i < io_hold_cnt + 2); 996 ma[i] = vm_page_grab_unlocked(obj, atop(off), 997 VM_ALLOC_NOCREAT | VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY | 998 VM_ALLOC_NOWAIT); 999 if (ma[i] == NULL) 1000 break; 1001 1002 /* 1003 * Skip invalid pages. Valid mask can be partial only 1004 * at EOF, and we clip later. 1005 */ 1006 if (vm_page_none_valid(ma[i])) { 1007 vm_page_sunbusy(ma[i]); 1008 break; 1009 } 1010 1011 resid -= PAGE_SIZE; 1012 off += PAGE_SIZE; 1013 } 1014 if (i == 0) { 1015 error = EJUSTRETURN; 1016 goto out_pip; 1017 } 1018 1019 /* 1020 * Check VIRF_DOOMED after we busied our pages. Since 1021 * vgonel() terminates the vnode' vm_object, it cannot 1022 * process past pages busied by us. 1023 */ 1024 if (VN_IS_DOOMED(vp)) { 1025 error = EJUSTRETURN; 1026 goto out; 1027 } 1028 1029 resid = PAGE_SIZE - (uio->uio_offset & PAGE_MASK) + ptoa(i - 1); 1030 if (resid > uio->uio_resid) 1031 resid = uio->uio_resid; 1032 1033 /* 1034 * Unlocked read of vnp_size is safe because truncation cannot 1035 * pass busied page. But we load vnp_size into a local 1036 * variable so that possible concurrent extension does not 1037 * break calculation. 1038 */ 1039 #if defined(__powerpc__) && !defined(__powerpc64__) 1040 vsz = obj->un_pager.vnp.vnp_size; 1041 #else 1042 vsz = atomic_load_64(&obj->un_pager.vnp.vnp_size); 1043 #endif 1044 if (uio->uio_offset >= vsz) { 1045 error = EJUSTRETURN; 1046 goto out; 1047 } 1048 if (uio->uio_offset + resid > vsz) 1049 resid = vsz - uio->uio_offset; 1050 1051 error = vn_io_fault_pgmove(ma, uio->uio_offset & PAGE_MASK, resid, uio); 1052 1053 out: 1054 for (j = 0; j < i; j++) { 1055 if (error == 0) 1056 vm_page_reference(ma[j]); 1057 vm_page_sunbusy(ma[j]); 1058 } 1059 out_pip: 1060 vm_object_pip_wakeup(obj); 1061 if (error != 0) 1062 return (error); 1063 return (uio->uio_resid == 0 ? 0 : EJUSTRETURN); 1064 } 1065 1066 /* 1067 * File table vnode read routine. 1068 */ 1069 static int 1070 vn_read(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, 1071 struct thread *td) 1072 { 1073 struct vnode *vp; 1074 off_t orig_offset; 1075 int error, ioflag; 1076 int advice; 1077 1078 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 1079 uio->uio_td, td)); 1080 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 1081 vp = fp->f_vnode; 1082 ioflag = 0; 1083 if (fp->f_flag & FNONBLOCK) 1084 ioflag |= IO_NDELAY; 1085 if (fp->f_flag & O_DIRECT) 1086 ioflag |= IO_DIRECT; 1087 1088 /* 1089 * Try to read from page cache. VIRF_DOOMED check is racy but 1090 * allows us to avoid unneeded work outright. 1091 */ 1092 if (vn_io_pgcache_read_enable && !mac_vnode_check_read_enabled() && 1093 (vn_irflag_read(vp) & (VIRF_DOOMED | VIRF_PGREAD)) == VIRF_PGREAD) { 1094 error = VOP_READ_PGCACHE(vp, uio, ioflag, fp->f_cred); 1095 if (error == 0) { 1096 fp->f_nextoff[UIO_READ] = uio->uio_offset; 1097 return (0); 1098 } 1099 if (error != EJUSTRETURN) 1100 return (error); 1101 } 1102 1103 advice = get_advice(fp, uio); 1104 vn_lock(vp, LK_SHARED | LK_RETRY); 1105 1106 switch (advice) { 1107 case POSIX_FADV_NORMAL: 1108 case POSIX_FADV_SEQUENTIAL: 1109 case POSIX_FADV_NOREUSE: 1110 ioflag |= sequential_heuristic(uio, fp); 1111 break; 1112 case POSIX_FADV_RANDOM: 1113 /* Disable read-ahead for random I/O. */ 1114 break; 1115 } 1116 orig_offset = uio->uio_offset; 1117 1118 #ifdef MAC 1119 error = mac_vnode_check_read(active_cred, fp->f_cred, vp); 1120 if (error == 0) 1121 #endif 1122 error = VOP_READ(vp, uio, ioflag, fp->f_cred); 1123 fp->f_nextoff[UIO_READ] = uio->uio_offset; 1124 VOP_UNLOCK(vp); 1125 if (error == 0 && advice == POSIX_FADV_NOREUSE && 1126 orig_offset != uio->uio_offset) 1127 /* 1128 * Use POSIX_FADV_DONTNEED to flush pages and buffers 1129 * for the backing file after a POSIX_FADV_NOREUSE 1130 * read(2). 1131 */ 1132 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 1133 POSIX_FADV_DONTNEED); 1134 return (error); 1135 } 1136 1137 /* 1138 * File table vnode write routine. 1139 */ 1140 static int 1141 vn_write(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, 1142 struct thread *td) 1143 { 1144 struct vnode *vp; 1145 struct mount *mp; 1146 off_t orig_offset; 1147 int error, ioflag; 1148 int advice; 1149 bool need_finished_write; 1150 1151 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 1152 uio->uio_td, td)); 1153 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 1154 vp = fp->f_vnode; 1155 if (vp->v_type == VREG) 1156 bwillwrite(); 1157 ioflag = IO_UNIT; 1158 if (vp->v_type == VREG && (fp->f_flag & O_APPEND) != 0) 1159 ioflag |= IO_APPEND; 1160 if ((fp->f_flag & FNONBLOCK) != 0) 1161 ioflag |= IO_NDELAY; 1162 ioflag |= get_write_ioflag(fp); 1163 1164 mp = NULL; 1165 need_finished_write = false; 1166 if (vp->v_type != VCHR) { 1167 error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH); 1168 if (error != 0) 1169 goto unlock; 1170 need_finished_write = true; 1171 } 1172 1173 advice = get_advice(fp, uio); 1174 1175 vn_lock(vp, vn_lktype_write(mp, vp) | LK_RETRY); 1176 switch (advice) { 1177 case POSIX_FADV_NORMAL: 1178 case POSIX_FADV_SEQUENTIAL: 1179 case POSIX_FADV_NOREUSE: 1180 ioflag |= sequential_heuristic(uio, fp); 1181 break; 1182 case POSIX_FADV_RANDOM: 1183 /* XXX: Is this correct? */ 1184 break; 1185 } 1186 orig_offset = uio->uio_offset; 1187 1188 #ifdef MAC 1189 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1190 if (error == 0) 1191 #endif 1192 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred); 1193 fp->f_nextoff[UIO_WRITE] = uio->uio_offset; 1194 VOP_UNLOCK(vp); 1195 if (need_finished_write) 1196 vn_finished_write(mp); 1197 if (error == 0 && advice == POSIX_FADV_NOREUSE && 1198 orig_offset != uio->uio_offset) 1199 /* 1200 * Use POSIX_FADV_DONTNEED to flush pages and buffers 1201 * for the backing file after a POSIX_FADV_NOREUSE 1202 * write(2). 1203 */ 1204 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 1205 POSIX_FADV_DONTNEED); 1206 unlock: 1207 return (error); 1208 } 1209 1210 /* 1211 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to 1212 * prevent the following deadlock: 1213 * 1214 * Assume that the thread A reads from the vnode vp1 into userspace 1215 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is 1216 * currently not resident, then system ends up with the call chain 1217 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] -> 1218 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2) 1219 * which establishes lock order vp1->vn_lock, then vp2->vn_lock. 1220 * If, at the same time, thread B reads from vnode vp2 into buffer buf2 1221 * backed by the pages of vnode vp1, and some page in buf2 is not 1222 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock. 1223 * 1224 * To prevent the lock order reversal and deadlock, vn_io_fault() does 1225 * not allow page faults to happen during VOP_READ() or VOP_WRITE(). 1226 * Instead, it first tries to do the whole range i/o with pagefaults 1227 * disabled. If all pages in the i/o buffer are resident and mapped, 1228 * VOP will succeed (ignoring the genuine filesystem errors). 1229 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do 1230 * i/o in chunks, with all pages in the chunk prefaulted and held 1231 * using vm_fault_quick_hold_pages(). 1232 * 1233 * Filesystems using this deadlock avoidance scheme should use the 1234 * array of the held pages from uio, saved in the curthread->td_ma, 1235 * instead of doing uiomove(). A helper function 1236 * vn_io_fault_uiomove() converts uiomove request into 1237 * uiomove_fromphys() over td_ma array. 1238 * 1239 * Since vnode locks do not cover the whole i/o anymore, rangelocks 1240 * make the current i/o request atomic with respect to other i/os and 1241 * truncations. 1242 */ 1243 1244 /* 1245 * Decode vn_io_fault_args and perform the corresponding i/o. 1246 */ 1247 static int 1248 vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio, 1249 struct thread *td) 1250 { 1251 int error, save; 1252 1253 error = 0; 1254 save = vm_fault_disable_pagefaults(); 1255 switch (args->kind) { 1256 case VN_IO_FAULT_FOP: 1257 error = (args->args.fop_args.doio)(args->args.fop_args.fp, 1258 uio, args->cred, args->flags, td); 1259 break; 1260 case VN_IO_FAULT_VOP: 1261 if (uio->uio_rw == UIO_READ) { 1262 error = VOP_READ(args->args.vop_args.vp, uio, 1263 args->flags, args->cred); 1264 } else if (uio->uio_rw == UIO_WRITE) { 1265 error = VOP_WRITE(args->args.vop_args.vp, uio, 1266 args->flags, args->cred); 1267 } 1268 break; 1269 default: 1270 panic("vn_io_fault_doio: unknown kind of io %d %d", 1271 args->kind, uio->uio_rw); 1272 } 1273 vm_fault_enable_pagefaults(save); 1274 return (error); 1275 } 1276 1277 static int 1278 vn_io_fault_touch(char *base, const struct uio *uio) 1279 { 1280 int r; 1281 1282 r = fubyte(base); 1283 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1)) 1284 return (EFAULT); 1285 return (0); 1286 } 1287 1288 static int 1289 vn_io_fault_prefault_user(const struct uio *uio) 1290 { 1291 char *base; 1292 const struct iovec *iov; 1293 size_t len; 1294 ssize_t resid; 1295 int error, i; 1296 1297 KASSERT(uio->uio_segflg == UIO_USERSPACE, 1298 ("vn_io_fault_prefault userspace")); 1299 1300 error = i = 0; 1301 iov = uio->uio_iov; 1302 resid = uio->uio_resid; 1303 base = iov->iov_base; 1304 len = iov->iov_len; 1305 while (resid > 0) { 1306 error = vn_io_fault_touch(base, uio); 1307 if (error != 0) 1308 break; 1309 if (len < PAGE_SIZE) { 1310 if (len != 0) { 1311 error = vn_io_fault_touch(base + len - 1, uio); 1312 if (error != 0) 1313 break; 1314 resid -= len; 1315 } 1316 if (++i >= uio->uio_iovcnt) 1317 break; 1318 iov = uio->uio_iov + i; 1319 base = iov->iov_base; 1320 len = iov->iov_len; 1321 } else { 1322 len -= PAGE_SIZE; 1323 base += PAGE_SIZE; 1324 resid -= PAGE_SIZE; 1325 } 1326 } 1327 return (error); 1328 } 1329 1330 /* 1331 * Common code for vn_io_fault(), agnostic to the kind of i/o request. 1332 * Uses vn_io_fault_doio() to make the call to an actual i/o function. 1333 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request 1334 * into args and call vn_io_fault1() to handle faults during the user 1335 * mode buffer accesses. 1336 */ 1337 static int 1338 vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args, 1339 struct thread *td) 1340 { 1341 vm_page_t ma[io_hold_cnt + 2]; 1342 struct uio *uio_clone, short_uio; 1343 struct iovec short_iovec[1]; 1344 vm_page_t *prev_td_ma; 1345 vm_prot_t prot; 1346 vm_offset_t addr, end; 1347 size_t len, resid; 1348 ssize_t adv; 1349 int error, cnt, saveheld, prev_td_ma_cnt; 1350 1351 if (vn_io_fault_prefault) { 1352 error = vn_io_fault_prefault_user(uio); 1353 if (error != 0) 1354 return (error); /* Or ignore ? */ 1355 } 1356 1357 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ; 1358 1359 /* 1360 * The UFS follows IO_UNIT directive and replays back both 1361 * uio_offset and uio_resid if an error is encountered during the 1362 * operation. But, since the iovec may be already advanced, 1363 * uio is still in an inconsistent state. 1364 * 1365 * Cache a copy of the original uio, which is advanced to the redo 1366 * point using UIO_NOCOPY below. 1367 */ 1368 uio_clone = cloneuio(uio); 1369 resid = uio->uio_resid; 1370 1371 short_uio.uio_segflg = UIO_USERSPACE; 1372 short_uio.uio_rw = uio->uio_rw; 1373 short_uio.uio_td = uio->uio_td; 1374 1375 error = vn_io_fault_doio(args, uio, td); 1376 if (error != EFAULT) 1377 goto out; 1378 1379 atomic_add_long(&vn_io_faults_cnt, 1); 1380 uio_clone->uio_segflg = UIO_NOCOPY; 1381 uiomove(NULL, resid - uio->uio_resid, uio_clone); 1382 uio_clone->uio_segflg = uio->uio_segflg; 1383 1384 saveheld = curthread_pflags_set(TDP_UIOHELD); 1385 prev_td_ma = td->td_ma; 1386 prev_td_ma_cnt = td->td_ma_cnt; 1387 1388 while (uio_clone->uio_resid != 0) { 1389 len = uio_clone->uio_iov->iov_len; 1390 if (len == 0) { 1391 KASSERT(uio_clone->uio_iovcnt >= 1, 1392 ("iovcnt underflow")); 1393 uio_clone->uio_iov++; 1394 uio_clone->uio_iovcnt--; 1395 continue; 1396 } 1397 if (len > ptoa(io_hold_cnt)) 1398 len = ptoa(io_hold_cnt); 1399 addr = (uintptr_t)uio_clone->uio_iov->iov_base; 1400 end = round_page(addr + len); 1401 if (end < addr) { 1402 error = EFAULT; 1403 break; 1404 } 1405 /* 1406 * A perfectly misaligned address and length could cause 1407 * both the start and the end of the chunk to use partial 1408 * page. +2 accounts for such a situation. 1409 */ 1410 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map, 1411 addr, len, prot, ma, io_hold_cnt + 2); 1412 if (cnt == -1) { 1413 error = EFAULT; 1414 break; 1415 } 1416 short_uio.uio_iov = &short_iovec[0]; 1417 short_iovec[0].iov_base = (void *)addr; 1418 short_uio.uio_iovcnt = 1; 1419 short_uio.uio_resid = short_iovec[0].iov_len = len; 1420 short_uio.uio_offset = uio_clone->uio_offset; 1421 td->td_ma = ma; 1422 td->td_ma_cnt = cnt; 1423 1424 error = vn_io_fault_doio(args, &short_uio, td); 1425 vm_page_unhold_pages(ma, cnt); 1426 adv = len - short_uio.uio_resid; 1427 1428 uio_clone->uio_iov->iov_base = 1429 (char *)uio_clone->uio_iov->iov_base + adv; 1430 uio_clone->uio_iov->iov_len -= adv; 1431 uio_clone->uio_resid -= adv; 1432 uio_clone->uio_offset += adv; 1433 1434 uio->uio_resid -= adv; 1435 uio->uio_offset += adv; 1436 1437 if (error != 0 || adv == 0) 1438 break; 1439 } 1440 td->td_ma = prev_td_ma; 1441 td->td_ma_cnt = prev_td_ma_cnt; 1442 curthread_pflags_restore(saveheld); 1443 out: 1444 free(uio_clone, M_IOV); 1445 return (error); 1446 } 1447 1448 static int 1449 vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred, 1450 int flags, struct thread *td) 1451 { 1452 fo_rdwr_t *doio; 1453 struct vnode *vp; 1454 void *rl_cookie; 1455 struct vn_io_fault_args args; 1456 int error; 1457 bool do_io_fault, do_rangelock; 1458 1459 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write; 1460 vp = fp->f_vnode; 1461 1462 /* 1463 * The ability to read(2) on a directory has historically been 1464 * allowed for all users, but this can and has been the source of 1465 * at least one security issue in the past. As such, it is now hidden 1466 * away behind a sysctl for those that actually need it to use it, and 1467 * restricted to root when it's turned on to make it relatively safe to 1468 * leave on for longer sessions of need. 1469 */ 1470 if (vp->v_type == VDIR) { 1471 KASSERT(uio->uio_rw == UIO_READ, 1472 ("illegal write attempted on a directory")); 1473 if (!vfs_allow_read_dir) 1474 return (EISDIR); 1475 if ((error = priv_check(td, PRIV_VFS_READ_DIR)) != 0) 1476 return (EISDIR); 1477 } 1478 1479 do_io_fault = do_vn_io_fault(vp, uio); 1480 do_rangelock = do_io_fault || (vn_irflag_read(vp) & VIRF_PGREAD) != 0; 1481 foffset_lock_uio(fp, uio, flags); 1482 if (do_rangelock) { 1483 if (uio->uio_rw == UIO_READ) { 1484 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset, 1485 uio->uio_offset + uio->uio_resid); 1486 } else if ((fp->f_flag & O_APPEND) != 0 || 1487 (flags & FOF_OFFSET) == 0) { 1488 /* For appenders, punt and lock the whole range. */ 1489 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1490 } else { 1491 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset, 1492 uio->uio_offset + uio->uio_resid); 1493 } 1494 } 1495 if (do_io_fault) { 1496 args.kind = VN_IO_FAULT_FOP; 1497 args.args.fop_args.fp = fp; 1498 args.args.fop_args.doio = doio; 1499 args.cred = active_cred; 1500 args.flags = flags | FOF_OFFSET; 1501 error = vn_io_fault1(vp, uio, &args, td); 1502 } else { 1503 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td); 1504 } 1505 if (do_rangelock) 1506 vn_rangelock_unlock(vp, rl_cookie); 1507 foffset_unlock_uio(fp, uio, flags); 1508 return (error); 1509 } 1510 1511 /* 1512 * Helper function to perform the requested uiomove operation using 1513 * the held pages for io->uio_iov[0].iov_base buffer instead of 1514 * copyin/copyout. Access to the pages with uiomove_fromphys() 1515 * instead of iov_base prevents page faults that could occur due to 1516 * pmap_collect() invalidating the mapping created by 1517 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or 1518 * object cleanup revoking the write access from page mappings. 1519 * 1520 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove() 1521 * instead of plain uiomove(). 1522 */ 1523 int 1524 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio) 1525 { 1526 struct uio transp_uio; 1527 struct iovec transp_iov[1]; 1528 struct thread *td; 1529 size_t adv; 1530 int error, pgadv; 1531 1532 td = curthread; 1533 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1534 uio->uio_segflg != UIO_USERSPACE) 1535 return (uiomove(data, xfersize, uio)); 1536 1537 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1538 transp_iov[0].iov_base = data; 1539 transp_uio.uio_iov = &transp_iov[0]; 1540 transp_uio.uio_iovcnt = 1; 1541 if (xfersize > uio->uio_resid) 1542 xfersize = uio->uio_resid; 1543 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize; 1544 transp_uio.uio_offset = 0; 1545 transp_uio.uio_segflg = UIO_SYSSPACE; 1546 /* 1547 * Since transp_iov points to data, and td_ma page array 1548 * corresponds to original uio->uio_iov, we need to invert the 1549 * direction of the i/o operation as passed to 1550 * uiomove_fromphys(). 1551 */ 1552 switch (uio->uio_rw) { 1553 case UIO_WRITE: 1554 transp_uio.uio_rw = UIO_READ; 1555 break; 1556 case UIO_READ: 1557 transp_uio.uio_rw = UIO_WRITE; 1558 break; 1559 } 1560 transp_uio.uio_td = uio->uio_td; 1561 error = uiomove_fromphys(td->td_ma, 1562 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK, 1563 xfersize, &transp_uio); 1564 adv = xfersize - transp_uio.uio_resid; 1565 pgadv = 1566 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) - 1567 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT); 1568 td->td_ma += pgadv; 1569 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1570 pgadv)); 1571 td->td_ma_cnt -= pgadv; 1572 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv; 1573 uio->uio_iov->iov_len -= adv; 1574 uio->uio_resid -= adv; 1575 uio->uio_offset += adv; 1576 return (error); 1577 } 1578 1579 int 1580 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize, 1581 struct uio *uio) 1582 { 1583 struct thread *td; 1584 vm_offset_t iov_base; 1585 int cnt, pgadv; 1586 1587 td = curthread; 1588 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1589 uio->uio_segflg != UIO_USERSPACE) 1590 return (uiomove_fromphys(ma, offset, xfersize, uio)); 1591 1592 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1593 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize; 1594 iov_base = (vm_offset_t)uio->uio_iov->iov_base; 1595 switch (uio->uio_rw) { 1596 case UIO_WRITE: 1597 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma, 1598 offset, cnt); 1599 break; 1600 case UIO_READ: 1601 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK, 1602 cnt); 1603 break; 1604 } 1605 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT); 1606 td->td_ma += pgadv; 1607 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1608 pgadv)); 1609 td->td_ma_cnt -= pgadv; 1610 uio->uio_iov->iov_base = (char *)(iov_base + cnt); 1611 uio->uio_iov->iov_len -= cnt; 1612 uio->uio_resid -= cnt; 1613 uio->uio_offset += cnt; 1614 return (0); 1615 } 1616 1617 /* 1618 * File table truncate routine. 1619 */ 1620 static int 1621 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1622 struct thread *td) 1623 { 1624 struct mount *mp; 1625 struct vnode *vp; 1626 void *rl_cookie; 1627 int error; 1628 1629 vp = fp->f_vnode; 1630 1631 retry: 1632 /* 1633 * Lock the whole range for truncation. Otherwise split i/o 1634 * might happen partly before and partly after the truncation. 1635 */ 1636 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1637 error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH); 1638 if (error) 1639 goto out1; 1640 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1641 AUDIT_ARG_VNODE1(vp); 1642 if (vp->v_type == VDIR) { 1643 error = EISDIR; 1644 goto out; 1645 } 1646 #ifdef MAC 1647 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1648 if (error) 1649 goto out; 1650 #endif 1651 error = vn_truncate_locked(vp, length, (fp->f_flag & O_FSYNC) != 0, 1652 fp->f_cred); 1653 out: 1654 VOP_UNLOCK(vp); 1655 vn_finished_write(mp); 1656 out1: 1657 vn_rangelock_unlock(vp, rl_cookie); 1658 if (error == ERELOOKUP) 1659 goto retry; 1660 return (error); 1661 } 1662 1663 /* 1664 * Truncate a file that is already locked. 1665 */ 1666 int 1667 vn_truncate_locked(struct vnode *vp, off_t length, bool sync, 1668 struct ucred *cred) 1669 { 1670 struct vattr vattr; 1671 int error; 1672 1673 error = VOP_ADD_WRITECOUNT(vp, 1); 1674 if (error == 0) { 1675 VATTR_NULL(&vattr); 1676 vattr.va_size = length; 1677 if (sync) 1678 vattr.va_vaflags |= VA_SYNC; 1679 error = VOP_SETATTR(vp, &vattr, cred); 1680 VOP_ADD_WRITECOUNT_CHECKED(vp, -1); 1681 } 1682 return (error); 1683 } 1684 1685 /* 1686 * File table vnode stat routine. 1687 */ 1688 int 1689 vn_statfile(struct file *fp, struct stat *sb, struct ucred *active_cred) 1690 { 1691 struct vnode *vp = fp->f_vnode; 1692 int error; 1693 1694 vn_lock(vp, LK_SHARED | LK_RETRY); 1695 error = VOP_STAT(vp, sb, active_cred, fp->f_cred); 1696 VOP_UNLOCK(vp); 1697 1698 return (error); 1699 } 1700 1701 /* 1702 * File table vnode ioctl routine. 1703 */ 1704 static int 1705 vn_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, 1706 struct thread *td) 1707 { 1708 struct vnode *vp; 1709 struct fiobmap2_arg *bmarg; 1710 off_t size; 1711 int error; 1712 1713 vp = fp->f_vnode; 1714 switch (vp->v_type) { 1715 case VDIR: 1716 case VREG: 1717 switch (com) { 1718 case FIONREAD: 1719 error = vn_getsize(vp, &size, active_cred); 1720 if (error == 0) 1721 *(int *)data = size - fp->f_offset; 1722 return (error); 1723 case FIOBMAP2: 1724 bmarg = (struct fiobmap2_arg *)data; 1725 vn_lock(vp, LK_SHARED | LK_RETRY); 1726 #ifdef MAC 1727 error = mac_vnode_check_read(active_cred, fp->f_cred, 1728 vp); 1729 if (error == 0) 1730 #endif 1731 error = VOP_BMAP(vp, bmarg->bn, NULL, 1732 &bmarg->bn, &bmarg->runp, &bmarg->runb); 1733 VOP_UNLOCK(vp); 1734 return (error); 1735 case FIONBIO: 1736 case FIOASYNC: 1737 return (0); 1738 default: 1739 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1740 active_cred, td)); 1741 } 1742 break; 1743 case VCHR: 1744 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1745 active_cred, td)); 1746 default: 1747 return (ENOTTY); 1748 } 1749 } 1750 1751 /* 1752 * File table vnode poll routine. 1753 */ 1754 static int 1755 vn_poll(struct file *fp, int events, struct ucred *active_cred, 1756 struct thread *td) 1757 { 1758 struct vnode *vp; 1759 int error; 1760 1761 vp = fp->f_vnode; 1762 #if defined(MAC) || defined(AUDIT) 1763 if (AUDITING_TD(td) || mac_vnode_check_poll_enabled()) { 1764 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1765 AUDIT_ARG_VNODE1(vp); 1766 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp); 1767 VOP_UNLOCK(vp); 1768 if (error != 0) 1769 return (error); 1770 } 1771 #endif 1772 error = VOP_POLL(vp, events, fp->f_cred, td); 1773 return (error); 1774 } 1775 1776 /* 1777 * Acquire the requested lock and then check for validity. LK_RETRY 1778 * permits vn_lock to return doomed vnodes. 1779 */ 1780 static int __noinline 1781 _vn_lock_fallback(struct vnode *vp, int flags, const char *file, int line, 1782 int error) 1783 { 1784 1785 KASSERT((flags & LK_RETRY) == 0 || error == 0, 1786 ("vn_lock: error %d incompatible with flags %#x", error, flags)); 1787 1788 if (error == 0) 1789 VNASSERT(VN_IS_DOOMED(vp), vp, ("vnode not doomed")); 1790 1791 if ((flags & LK_RETRY) == 0) { 1792 if (error == 0) { 1793 VOP_UNLOCK(vp); 1794 error = ENOENT; 1795 } 1796 return (error); 1797 } 1798 1799 /* 1800 * LK_RETRY case. 1801 * 1802 * Nothing to do if we got the lock. 1803 */ 1804 if (error == 0) 1805 return (0); 1806 1807 /* 1808 * Interlock was dropped by the call in _vn_lock. 1809 */ 1810 flags &= ~LK_INTERLOCK; 1811 do { 1812 error = VOP_LOCK1(vp, flags, file, line); 1813 } while (error != 0); 1814 return (0); 1815 } 1816 1817 int 1818 _vn_lock(struct vnode *vp, int flags, const char *file, int line) 1819 { 1820 int error; 1821 1822 VNASSERT((flags & LK_TYPE_MASK) != 0, vp, 1823 ("vn_lock: no locktype (%d passed)", flags)); 1824 VNPASS(vp->v_holdcnt > 0, vp); 1825 error = VOP_LOCK1(vp, flags, file, line); 1826 if (__predict_false(error != 0 || VN_IS_DOOMED(vp))) 1827 return (_vn_lock_fallback(vp, flags, file, line, error)); 1828 return (0); 1829 } 1830 1831 /* 1832 * File table vnode close routine. 1833 */ 1834 static int 1835 vn_closefile(struct file *fp, struct thread *td) 1836 { 1837 struct vnode *vp; 1838 struct flock lf; 1839 int error; 1840 bool ref; 1841 1842 vp = fp->f_vnode; 1843 fp->f_ops = &badfileops; 1844 ref = (fp->f_flag & FHASLOCK) != 0; 1845 1846 error = vn_close1(vp, fp->f_flag, fp->f_cred, td, ref); 1847 1848 if (__predict_false(ref)) { 1849 lf.l_whence = SEEK_SET; 1850 lf.l_start = 0; 1851 lf.l_len = 0; 1852 lf.l_type = F_UNLCK; 1853 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK); 1854 vrele(vp); 1855 } 1856 return (error); 1857 } 1858 1859 /* 1860 * Preparing to start a filesystem write operation. If the operation is 1861 * permitted, then we bump the count of operations in progress and 1862 * proceed. If a suspend request is in progress, we wait until the 1863 * suspension is over, and then proceed. 1864 */ 1865 static int 1866 vn_start_write_refed(struct mount *mp, int flags, bool mplocked) 1867 { 1868 struct mount_pcpu *mpcpu; 1869 int error, mflags; 1870 1871 if (__predict_true(!mplocked) && (flags & V_XSLEEP) == 0 && 1872 vfs_op_thread_enter(mp, mpcpu)) { 1873 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 1874 vfs_mp_count_add_pcpu(mpcpu, writeopcount, 1); 1875 vfs_op_thread_exit(mp, mpcpu); 1876 return (0); 1877 } 1878 1879 if (mplocked) 1880 mtx_assert(MNT_MTX(mp), MA_OWNED); 1881 else 1882 MNT_ILOCK(mp); 1883 1884 error = 0; 1885 1886 /* 1887 * Check on status of suspension. 1888 */ 1889 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 || 1890 mp->mnt_susp_owner != curthread) { 1891 mflags = 0; 1892 if ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0) { 1893 if (flags & V_PCATCH) 1894 mflags |= PCATCH; 1895 } 1896 mflags |= (PUSER - 1); 1897 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1898 if ((flags & V_NOWAIT) != 0) { 1899 error = EWOULDBLOCK; 1900 goto unlock; 1901 } 1902 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, 1903 "suspfs", 0); 1904 if (error != 0) 1905 goto unlock; 1906 } 1907 } 1908 if ((flags & V_XSLEEP) != 0) 1909 goto unlock; 1910 mp->mnt_writeopcount++; 1911 unlock: 1912 if (error != 0 || (flags & V_XSLEEP) != 0) 1913 MNT_REL(mp); 1914 MNT_IUNLOCK(mp); 1915 return (error); 1916 } 1917 1918 int 1919 vn_start_write(struct vnode *vp, struct mount **mpp, int flags) 1920 { 1921 struct mount *mp; 1922 int error; 1923 1924 KASSERT((flags & ~V_VALID_FLAGS) == 0, 1925 ("%s: invalid flags passed %d\n", __func__, flags)); 1926 1927 error = 0; 1928 /* 1929 * If a vnode is provided, get and return the mount point that 1930 * to which it will write. 1931 */ 1932 if (vp != NULL) { 1933 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1934 *mpp = NULL; 1935 if (error != EOPNOTSUPP) 1936 return (error); 1937 return (0); 1938 } 1939 } 1940 if ((mp = *mpp) == NULL) 1941 return (0); 1942 1943 /* 1944 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1945 * a vfs_ref(). 1946 * As long as a vnode is not provided we need to acquire a 1947 * refcount for the provided mountpoint too, in order to 1948 * emulate a vfs_ref(). 1949 */ 1950 if (vp == NULL) 1951 vfs_ref(mp); 1952 1953 error = vn_start_write_refed(mp, flags, false); 1954 if (error != 0 && (flags & V_NOWAIT) == 0) 1955 *mpp = NULL; 1956 return (error); 1957 } 1958 1959 /* 1960 * Secondary suspension. Used by operations such as vop_inactive 1961 * routines that are needed by the higher level functions. These 1962 * are allowed to proceed until all the higher level functions have 1963 * completed (indicated by mnt_writeopcount dropping to zero). At that 1964 * time, these operations are halted until the suspension is over. 1965 */ 1966 int 1967 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags) 1968 { 1969 struct mount *mp; 1970 int error, mflags; 1971 1972 KASSERT((flags & (~V_VALID_FLAGS | V_XSLEEP)) == 0, 1973 ("%s: invalid flags passed %d\n", __func__, flags)); 1974 1975 retry: 1976 if (vp != NULL) { 1977 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1978 *mpp = NULL; 1979 if (error != EOPNOTSUPP) 1980 return (error); 1981 return (0); 1982 } 1983 } 1984 /* 1985 * If we are not suspended or have not yet reached suspended 1986 * mode, then let the operation proceed. 1987 */ 1988 if ((mp = *mpp) == NULL) 1989 return (0); 1990 1991 /* 1992 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1993 * a vfs_ref(). 1994 * As long as a vnode is not provided we need to acquire a 1995 * refcount for the provided mountpoint too, in order to 1996 * emulate a vfs_ref(). 1997 */ 1998 MNT_ILOCK(mp); 1999 if (vp == NULL) 2000 MNT_REF(mp); 2001 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) { 2002 mp->mnt_secondary_writes++; 2003 mp->mnt_secondary_accwrites++; 2004 MNT_IUNLOCK(mp); 2005 return (0); 2006 } 2007 if ((flags & V_NOWAIT) != 0) { 2008 MNT_REL(mp); 2009 MNT_IUNLOCK(mp); 2010 *mpp = NULL; 2011 return (EWOULDBLOCK); 2012 } 2013 /* 2014 * Wait for the suspension to finish. 2015 */ 2016 mflags = 0; 2017 if ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0) { 2018 if ((flags & V_PCATCH) != 0) 2019 mflags |= PCATCH; 2020 } 2021 mflags |= (PUSER - 1) | PDROP; 2022 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, "suspfs", 0); 2023 vfs_rel(mp); 2024 if (error == 0) 2025 goto retry; 2026 *mpp = NULL; 2027 return (error); 2028 } 2029 2030 /* 2031 * Filesystem write operation has completed. If we are suspending and this 2032 * operation is the last one, notify the suspender that the suspension is 2033 * now in effect. 2034 */ 2035 void 2036 vn_finished_write(struct mount *mp) 2037 { 2038 struct mount_pcpu *mpcpu; 2039 int c; 2040 2041 if (mp == NULL) 2042 return; 2043 2044 if (vfs_op_thread_enter(mp, mpcpu)) { 2045 vfs_mp_count_sub_pcpu(mpcpu, writeopcount, 1); 2046 vfs_mp_count_sub_pcpu(mpcpu, ref, 1); 2047 vfs_op_thread_exit(mp, mpcpu); 2048 return; 2049 } 2050 2051 MNT_ILOCK(mp); 2052 vfs_assert_mount_counters(mp); 2053 MNT_REL(mp); 2054 c = --mp->mnt_writeopcount; 2055 if (mp->mnt_vfs_ops == 0) { 2056 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 2057 MNT_IUNLOCK(mp); 2058 return; 2059 } 2060 if (c < 0) 2061 vfs_dump_mount_counters(mp); 2062 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && c == 0) 2063 wakeup(&mp->mnt_writeopcount); 2064 MNT_IUNLOCK(mp); 2065 } 2066 2067 /* 2068 * Filesystem secondary write operation has completed. If we are 2069 * suspending and this operation is the last one, notify the suspender 2070 * that the suspension is now in effect. 2071 */ 2072 void 2073 vn_finished_secondary_write(struct mount *mp) 2074 { 2075 if (mp == NULL) 2076 return; 2077 MNT_ILOCK(mp); 2078 MNT_REL(mp); 2079 mp->mnt_secondary_writes--; 2080 if (mp->mnt_secondary_writes < 0) 2081 panic("vn_finished_secondary_write: neg cnt"); 2082 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 2083 mp->mnt_secondary_writes <= 0) 2084 wakeup(&mp->mnt_secondary_writes); 2085 MNT_IUNLOCK(mp); 2086 } 2087 2088 /* 2089 * Request a filesystem to suspend write operations. 2090 */ 2091 int 2092 vfs_write_suspend(struct mount *mp, int flags) 2093 { 2094 int error; 2095 2096 vfs_op_enter(mp); 2097 2098 MNT_ILOCK(mp); 2099 vfs_assert_mount_counters(mp); 2100 if (mp->mnt_susp_owner == curthread) { 2101 vfs_op_exit_locked(mp); 2102 MNT_IUNLOCK(mp); 2103 return (EALREADY); 2104 } 2105 while (mp->mnt_kern_flag & MNTK_SUSPEND) 2106 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0); 2107 2108 /* 2109 * Unmount holds a write reference on the mount point. If we 2110 * own busy reference and drain for writers, we deadlock with 2111 * the reference draining in the unmount path. Callers of 2112 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if 2113 * vfs_busy() reference is owned and caller is not in the 2114 * unmount context. 2115 */ 2116 if ((flags & VS_SKIP_UNMOUNT) != 0 && 2117 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) { 2118 vfs_op_exit_locked(mp); 2119 MNT_IUNLOCK(mp); 2120 return (EBUSY); 2121 } 2122 2123 mp->mnt_kern_flag |= MNTK_SUSPEND; 2124 mp->mnt_susp_owner = curthread; 2125 if (mp->mnt_writeopcount > 0) 2126 (void) msleep(&mp->mnt_writeopcount, 2127 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0); 2128 else 2129 MNT_IUNLOCK(mp); 2130 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0) { 2131 vfs_write_resume(mp, 0); 2132 /* vfs_write_resume does vfs_op_exit() for us */ 2133 } 2134 return (error); 2135 } 2136 2137 /* 2138 * Request a filesystem to resume write operations. 2139 */ 2140 void 2141 vfs_write_resume(struct mount *mp, int flags) 2142 { 2143 2144 MNT_ILOCK(mp); 2145 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 2146 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner")); 2147 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 | 2148 MNTK_SUSPENDED); 2149 mp->mnt_susp_owner = NULL; 2150 wakeup(&mp->mnt_writeopcount); 2151 wakeup(&mp->mnt_flag); 2152 curthread->td_pflags &= ~TDP_IGNSUSP; 2153 if ((flags & VR_START_WRITE) != 0) { 2154 MNT_REF(mp); 2155 mp->mnt_writeopcount++; 2156 } 2157 MNT_IUNLOCK(mp); 2158 if ((flags & VR_NO_SUSPCLR) == 0) 2159 VFS_SUSP_CLEAN(mp); 2160 vfs_op_exit(mp); 2161 } else if ((flags & VR_START_WRITE) != 0) { 2162 MNT_REF(mp); 2163 vn_start_write_refed(mp, 0, true); 2164 } else { 2165 MNT_IUNLOCK(mp); 2166 } 2167 } 2168 2169 /* 2170 * Helper loop around vfs_write_suspend() for filesystem unmount VFS 2171 * methods. 2172 */ 2173 int 2174 vfs_write_suspend_umnt(struct mount *mp) 2175 { 2176 int error; 2177 2178 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0, 2179 ("vfs_write_suspend_umnt: recursed")); 2180 2181 /* dounmount() already called vn_start_write(). */ 2182 for (;;) { 2183 vn_finished_write(mp); 2184 error = vfs_write_suspend(mp, 0); 2185 if (error != 0) { 2186 vn_start_write(NULL, &mp, V_WAIT); 2187 return (error); 2188 } 2189 MNT_ILOCK(mp); 2190 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0) 2191 break; 2192 MNT_IUNLOCK(mp); 2193 vn_start_write(NULL, &mp, V_WAIT); 2194 } 2195 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2); 2196 wakeup(&mp->mnt_flag); 2197 MNT_IUNLOCK(mp); 2198 curthread->td_pflags |= TDP_IGNSUSP; 2199 return (0); 2200 } 2201 2202 /* 2203 * Implement kqueues for files by translating it to vnode operation. 2204 */ 2205 static int 2206 vn_kqfilter(struct file *fp, struct knote *kn) 2207 { 2208 2209 return (VOP_KQFILTER(fp->f_vnode, kn)); 2210 } 2211 2212 int 2213 vn_kqfilter_opath(struct file *fp, struct knote *kn) 2214 { 2215 if ((fp->f_flag & FKQALLOWED) == 0) 2216 return (EBADF); 2217 return (vn_kqfilter(fp, kn)); 2218 } 2219 2220 /* 2221 * Simplified in-kernel wrapper calls for extended attribute access. 2222 * Both calls pass in a NULL credential, authorizing as "kernel" access. 2223 * Set IO_NODELOCKED in ioflg if the vnode is already locked. 2224 */ 2225 int 2226 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace, 2227 const char *attrname, int *buflen, char *buf, struct thread *td) 2228 { 2229 struct uio auio; 2230 struct iovec iov; 2231 int error; 2232 2233 iov.iov_len = *buflen; 2234 iov.iov_base = buf; 2235 2236 auio.uio_iov = &iov; 2237 auio.uio_iovcnt = 1; 2238 auio.uio_rw = UIO_READ; 2239 auio.uio_segflg = UIO_SYSSPACE; 2240 auio.uio_td = td; 2241 auio.uio_offset = 0; 2242 auio.uio_resid = *buflen; 2243 2244 if ((ioflg & IO_NODELOCKED) == 0) 2245 vn_lock(vp, LK_SHARED | LK_RETRY); 2246 2247 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2248 2249 /* authorize attribute retrieval as kernel */ 2250 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL, 2251 td); 2252 2253 if ((ioflg & IO_NODELOCKED) == 0) 2254 VOP_UNLOCK(vp); 2255 2256 if (error == 0) { 2257 *buflen = *buflen - auio.uio_resid; 2258 } 2259 2260 return (error); 2261 } 2262 2263 /* 2264 * XXX failure mode if partially written? 2265 */ 2266 int 2267 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace, 2268 const char *attrname, int buflen, char *buf, struct thread *td) 2269 { 2270 struct uio auio; 2271 struct iovec iov; 2272 struct mount *mp; 2273 int error; 2274 2275 iov.iov_len = buflen; 2276 iov.iov_base = buf; 2277 2278 auio.uio_iov = &iov; 2279 auio.uio_iovcnt = 1; 2280 auio.uio_rw = UIO_WRITE; 2281 auio.uio_segflg = UIO_SYSSPACE; 2282 auio.uio_td = td; 2283 auio.uio_offset = 0; 2284 auio.uio_resid = buflen; 2285 2286 if ((ioflg & IO_NODELOCKED) == 0) { 2287 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2288 return (error); 2289 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2290 } 2291 2292 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2293 2294 /* authorize attribute setting as kernel */ 2295 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td); 2296 2297 if ((ioflg & IO_NODELOCKED) == 0) { 2298 vn_finished_write(mp); 2299 VOP_UNLOCK(vp); 2300 } 2301 2302 return (error); 2303 } 2304 2305 int 2306 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace, 2307 const char *attrname, struct thread *td) 2308 { 2309 struct mount *mp; 2310 int error; 2311 2312 if ((ioflg & IO_NODELOCKED) == 0) { 2313 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2314 return (error); 2315 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2316 } 2317 2318 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2319 2320 /* authorize attribute removal as kernel */ 2321 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td); 2322 if (error == EOPNOTSUPP) 2323 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL, 2324 NULL, td); 2325 2326 if ((ioflg & IO_NODELOCKED) == 0) { 2327 vn_finished_write(mp); 2328 VOP_UNLOCK(vp); 2329 } 2330 2331 return (error); 2332 } 2333 2334 static int 2335 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags, 2336 struct vnode **rvp) 2337 { 2338 2339 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp)); 2340 } 2341 2342 int 2343 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp) 2344 { 2345 2346 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino, 2347 lkflags, rvp)); 2348 } 2349 2350 int 2351 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg, 2352 int lkflags, struct vnode **rvp) 2353 { 2354 struct mount *mp; 2355 int ltype, error; 2356 2357 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get"); 2358 mp = vp->v_mount; 2359 ltype = VOP_ISLOCKED(vp); 2360 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED, 2361 ("vn_vget_ino: vp not locked")); 2362 error = vfs_busy(mp, MBF_NOWAIT); 2363 if (error != 0) { 2364 vfs_ref(mp); 2365 VOP_UNLOCK(vp); 2366 error = vfs_busy(mp, 0); 2367 vn_lock(vp, ltype | LK_RETRY); 2368 vfs_rel(mp); 2369 if (error != 0) 2370 return (ENOENT); 2371 if (VN_IS_DOOMED(vp)) { 2372 vfs_unbusy(mp); 2373 return (ENOENT); 2374 } 2375 } 2376 VOP_UNLOCK(vp); 2377 error = alloc(mp, alloc_arg, lkflags, rvp); 2378 vfs_unbusy(mp); 2379 if (error != 0 || *rvp != vp) 2380 vn_lock(vp, ltype | LK_RETRY); 2381 if (VN_IS_DOOMED(vp)) { 2382 if (error == 0) { 2383 if (*rvp == vp) 2384 vunref(vp); 2385 else 2386 vput(*rvp); 2387 } 2388 error = ENOENT; 2389 } 2390 return (error); 2391 } 2392 2393 static void 2394 vn_send_sigxfsz(struct proc *p) 2395 { 2396 PROC_LOCK(p); 2397 kern_psignal(p, SIGXFSZ); 2398 PROC_UNLOCK(p); 2399 } 2400 2401 int 2402 vn_rlimit_trunc(u_quad_t size, struct thread *td) 2403 { 2404 if (size <= lim_cur(td, RLIMIT_FSIZE)) 2405 return (0); 2406 vn_send_sigxfsz(td->td_proc); 2407 return (EFBIG); 2408 } 2409 2410 static int 2411 vn_rlimit_fsizex1(const struct vnode *vp, struct uio *uio, off_t maxfsz, 2412 bool adj, struct thread *td) 2413 { 2414 off_t lim; 2415 bool ktr_write; 2416 2417 if (vp->v_type != VREG) 2418 return (0); 2419 2420 /* 2421 * Handle file system maximum file size. 2422 */ 2423 if (maxfsz != 0 && uio->uio_offset + uio->uio_resid > maxfsz) { 2424 if (!adj || uio->uio_offset >= maxfsz) 2425 return (EFBIG); 2426 uio->uio_resid = maxfsz - uio->uio_offset; 2427 } 2428 2429 /* 2430 * This is kernel write (e.g. vnode_pager) or accounting 2431 * write, ignore limit. 2432 */ 2433 if (td == NULL || (td->td_pflags2 & TDP2_ACCT) != 0) 2434 return (0); 2435 2436 /* 2437 * Calculate file size limit. 2438 */ 2439 ktr_write = (td->td_pflags & TDP_INKTRACE) != 0; 2440 lim = __predict_false(ktr_write) ? td->td_ktr_io_lim : 2441 lim_cur(td, RLIMIT_FSIZE); 2442 2443 /* 2444 * Is the limit reached? 2445 */ 2446 if (__predict_true((uoff_t)uio->uio_offset + uio->uio_resid <= lim)) 2447 return (0); 2448 2449 /* 2450 * Prepared filesystems can handle writes truncated to the 2451 * file size limit. 2452 */ 2453 if (adj && (uoff_t)uio->uio_offset < lim) { 2454 uio->uio_resid = lim - (uoff_t)uio->uio_offset; 2455 return (0); 2456 } 2457 2458 if (!ktr_write || ktr_filesize_limit_signal) 2459 vn_send_sigxfsz(td->td_proc); 2460 return (EFBIG); 2461 } 2462 2463 /* 2464 * Helper for VOP_WRITE() implementations, the common code to 2465 * handle maximum supported file size on the filesystem, and 2466 * RLIMIT_FSIZE, except for special writes from accounting subsystem 2467 * and ktrace. 2468 * 2469 * For maximum file size (maxfsz argument): 2470 * - return EFBIG if uio_offset is beyond it 2471 * - otherwise, clamp uio_resid if write would extend file beyond maxfsz. 2472 * 2473 * For RLIMIT_FSIZE: 2474 * - return EFBIG and send SIGXFSZ if uio_offset is beyond the limit 2475 * - otherwise, clamp uio_resid if write would extend file beyond limit. 2476 * 2477 * If clamping occured, the adjustment for uio_resid is stored in 2478 * *resid_adj, to be re-applied by vn_rlimit_fsizex_res() on return 2479 * from the VOP. 2480 */ 2481 int 2482 vn_rlimit_fsizex(const struct vnode *vp, struct uio *uio, off_t maxfsz, 2483 ssize_t *resid_adj, struct thread *td) 2484 { 2485 ssize_t resid_orig; 2486 int error; 2487 bool adj; 2488 2489 resid_orig = uio->uio_resid; 2490 adj = resid_adj != NULL; 2491 error = vn_rlimit_fsizex1(vp, uio, maxfsz, adj, td); 2492 if (adj) 2493 *resid_adj = resid_orig - uio->uio_resid; 2494 return (error); 2495 } 2496 2497 void 2498 vn_rlimit_fsizex_res(struct uio *uio, ssize_t resid_adj) 2499 { 2500 uio->uio_resid += resid_adj; 2501 } 2502 2503 int 2504 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio, 2505 struct thread *td) 2506 { 2507 return (vn_rlimit_fsizex(vp, __DECONST(struct uio *, uio), 0, NULL, 2508 td)); 2509 } 2510 2511 int 2512 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 2513 struct thread *td) 2514 { 2515 struct vnode *vp; 2516 2517 vp = fp->f_vnode; 2518 #ifdef AUDIT 2519 vn_lock(vp, LK_SHARED | LK_RETRY); 2520 AUDIT_ARG_VNODE1(vp); 2521 VOP_UNLOCK(vp); 2522 #endif 2523 return (setfmode(td, active_cred, vp, mode)); 2524 } 2525 2526 int 2527 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 2528 struct thread *td) 2529 { 2530 struct vnode *vp; 2531 2532 vp = fp->f_vnode; 2533 #ifdef AUDIT 2534 vn_lock(vp, LK_SHARED | LK_RETRY); 2535 AUDIT_ARG_VNODE1(vp); 2536 VOP_UNLOCK(vp); 2537 #endif 2538 return (setfown(td, active_cred, vp, uid, gid)); 2539 } 2540 2541 /* 2542 * Remove pages in the range ["start", "end") from the vnode's VM object. If 2543 * "end" is 0, then the range extends to the end of the object. 2544 */ 2545 void 2546 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 2547 { 2548 vm_object_t object; 2549 2550 if ((object = vp->v_object) == NULL) 2551 return; 2552 VM_OBJECT_WLOCK(object); 2553 vm_object_page_remove(object, start, end, 0); 2554 VM_OBJECT_WUNLOCK(object); 2555 } 2556 2557 /* 2558 * Like vn_pages_remove(), but skips invalid pages, which by definition are not 2559 * mapped into any process' address space. Filesystems may use this in 2560 * preference to vn_pages_remove() to avoid blocking on pages busied in 2561 * preparation for a VOP_GETPAGES. 2562 */ 2563 void 2564 vn_pages_remove_valid(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 2565 { 2566 vm_object_t object; 2567 2568 if ((object = vp->v_object) == NULL) 2569 return; 2570 VM_OBJECT_WLOCK(object); 2571 vm_object_page_remove(object, start, end, OBJPR_VALIDONLY); 2572 VM_OBJECT_WUNLOCK(object); 2573 } 2574 2575 int 2576 vn_bmap_seekhole_locked(struct vnode *vp, u_long cmd, off_t *off, 2577 struct ucred *cred) 2578 { 2579 off_t size; 2580 daddr_t bn, bnp; 2581 uint64_t bsize; 2582 off_t noff; 2583 int error; 2584 2585 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2586 ("%s: Wrong command %lu", __func__, cmd)); 2587 ASSERT_VOP_ELOCKED(vp, "vn_bmap_seekhole_locked"); 2588 2589 if (vp->v_type != VREG) { 2590 error = ENOTTY; 2591 goto out; 2592 } 2593 error = vn_getsize_locked(vp, &size, cred); 2594 if (error != 0) 2595 goto out; 2596 noff = *off; 2597 if (noff < 0 || noff >= size) { 2598 error = ENXIO; 2599 goto out; 2600 } 2601 2602 /* See the comment in ufs_bmap_seekdata(). */ 2603 vnode_pager_clean_sync(vp); 2604 2605 bsize = vp->v_mount->mnt_stat.f_iosize; 2606 for (bn = noff / bsize; noff < size; bn++, noff += bsize - 2607 noff % bsize) { 2608 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL); 2609 if (error == EOPNOTSUPP) { 2610 error = ENOTTY; 2611 goto out; 2612 } 2613 if ((bnp == -1 && cmd == FIOSEEKHOLE) || 2614 (bnp != -1 && cmd == FIOSEEKDATA)) { 2615 noff = bn * bsize; 2616 if (noff < *off) 2617 noff = *off; 2618 goto out; 2619 } 2620 } 2621 if (noff > size) 2622 noff = size; 2623 /* noff == size. There is an implicit hole at the end of file. */ 2624 if (cmd == FIOSEEKDATA) 2625 error = ENXIO; 2626 out: 2627 if (error == 0) 2628 *off = noff; 2629 return (error); 2630 } 2631 2632 int 2633 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred) 2634 { 2635 int error; 2636 2637 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2638 ("%s: Wrong command %lu", __func__, cmd)); 2639 2640 if (vn_lock(vp, LK_EXCLUSIVE) != 0) 2641 return (EBADF); 2642 error = vn_bmap_seekhole_locked(vp, cmd, off, cred); 2643 VOP_UNLOCK(vp); 2644 return (error); 2645 } 2646 2647 int 2648 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td) 2649 { 2650 struct ucred *cred; 2651 struct vnode *vp; 2652 off_t foffset, fsize, size; 2653 int error, noneg; 2654 2655 cred = td->td_ucred; 2656 vp = fp->f_vnode; 2657 noneg = (vp->v_type != VCHR); 2658 /* 2659 * Try to dodge locking for common case of querying the offset. 2660 */ 2661 if (whence == L_INCR && offset == 0) { 2662 foffset = foffset_read(fp); 2663 if (__predict_false(foffset < 0 && noneg)) { 2664 return (EOVERFLOW); 2665 } 2666 td->td_uretoff.tdu_off = foffset; 2667 return (0); 2668 } 2669 foffset = foffset_lock(fp, 0); 2670 error = 0; 2671 switch (whence) { 2672 case L_INCR: 2673 if (noneg && 2674 (foffset < 0 || 2675 (offset > 0 && foffset > OFF_MAX - offset))) { 2676 error = EOVERFLOW; 2677 break; 2678 } 2679 offset += foffset; 2680 break; 2681 case L_XTND: 2682 error = vn_getsize(vp, &fsize, cred); 2683 if (error != 0) 2684 break; 2685 2686 /* 2687 * If the file references a disk device, then fetch 2688 * the media size and use that to determine the ending 2689 * offset. 2690 */ 2691 if (fsize == 0 && vp->v_type == VCHR && 2692 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0) 2693 fsize = size; 2694 if (noneg && offset > 0 && fsize > OFF_MAX - offset) { 2695 error = EOVERFLOW; 2696 break; 2697 } 2698 offset += fsize; 2699 break; 2700 case L_SET: 2701 break; 2702 case SEEK_DATA: 2703 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td); 2704 if (error == ENOTTY) 2705 error = EINVAL; 2706 break; 2707 case SEEK_HOLE: 2708 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td); 2709 if (error == ENOTTY) 2710 error = EINVAL; 2711 break; 2712 default: 2713 error = EINVAL; 2714 } 2715 if (error == 0 && noneg && offset < 0) 2716 error = EINVAL; 2717 if (error != 0) 2718 goto drop; 2719 VFS_KNOTE_UNLOCKED(vp, 0); 2720 td->td_uretoff.tdu_off = offset; 2721 drop: 2722 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0); 2723 return (error); 2724 } 2725 2726 int 2727 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred, 2728 struct thread *td) 2729 { 2730 int error; 2731 2732 /* 2733 * Grant permission if the caller is the owner of the file, or 2734 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on 2735 * on the file. If the time pointer is null, then write 2736 * permission on the file is also sufficient. 2737 * 2738 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes: 2739 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES 2740 * will be allowed to set the times [..] to the current 2741 * server time. 2742 */ 2743 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td); 2744 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0) 2745 error = VOP_ACCESS(vp, VWRITE, cred, td); 2746 return (error); 2747 } 2748 2749 int 2750 vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2751 { 2752 struct vnode *vp; 2753 int error; 2754 2755 if (fp->f_type == DTYPE_FIFO) 2756 kif->kf_type = KF_TYPE_FIFO; 2757 else 2758 kif->kf_type = KF_TYPE_VNODE; 2759 vp = fp->f_vnode; 2760 vref(vp); 2761 FILEDESC_SUNLOCK(fdp); 2762 error = vn_fill_kinfo_vnode(vp, kif); 2763 vrele(vp); 2764 FILEDESC_SLOCK(fdp); 2765 return (error); 2766 } 2767 2768 static inline void 2769 vn_fill_junk(struct kinfo_file *kif) 2770 { 2771 size_t len, olen; 2772 2773 /* 2774 * Simulate vn_fullpath returning changing values for a given 2775 * vp during e.g. coredump. 2776 */ 2777 len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1; 2778 olen = strlen(kif->kf_path); 2779 if (len < olen) 2780 strcpy(&kif->kf_path[len - 1], "$"); 2781 else 2782 for (; olen < len; olen++) 2783 strcpy(&kif->kf_path[olen], "A"); 2784 } 2785 2786 int 2787 vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif) 2788 { 2789 struct vattr va; 2790 char *fullpath, *freepath; 2791 int error; 2792 2793 kif->kf_un.kf_file.kf_file_type = vntype_to_kinfo(vp->v_type); 2794 freepath = NULL; 2795 fullpath = "-"; 2796 error = vn_fullpath(vp, &fullpath, &freepath); 2797 if (error == 0) { 2798 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path)); 2799 } 2800 if (freepath != NULL) 2801 free(freepath, M_TEMP); 2802 2803 KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path, 2804 vn_fill_junk(kif); 2805 ); 2806 2807 /* 2808 * Retrieve vnode attributes. 2809 */ 2810 va.va_fsid = VNOVAL; 2811 va.va_rdev = NODEV; 2812 vn_lock(vp, LK_SHARED | LK_RETRY); 2813 error = VOP_GETATTR(vp, &va, curthread->td_ucred); 2814 VOP_UNLOCK(vp); 2815 if (error != 0) 2816 return (error); 2817 if (va.va_fsid != VNOVAL) 2818 kif->kf_un.kf_file.kf_file_fsid = va.va_fsid; 2819 else 2820 kif->kf_un.kf_file.kf_file_fsid = 2821 vp->v_mount->mnt_stat.f_fsid.val[0]; 2822 kif->kf_un.kf_file.kf_file_fsid_freebsd11 = 2823 kif->kf_un.kf_file.kf_file_fsid; /* truncate */ 2824 kif->kf_un.kf_file.kf_file_fileid = va.va_fileid; 2825 kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode); 2826 kif->kf_un.kf_file.kf_file_size = va.va_size; 2827 kif->kf_un.kf_file.kf_file_rdev = va.va_rdev; 2828 kif->kf_un.kf_file.kf_file_rdev_freebsd11 = 2829 kif->kf_un.kf_file.kf_file_rdev; /* truncate */ 2830 kif->kf_un.kf_file.kf_file_nlink = va.va_nlink; 2831 return (0); 2832 } 2833 2834 int 2835 vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size, 2836 vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff, 2837 struct thread *td) 2838 { 2839 #ifdef HWPMC_HOOKS 2840 struct pmckern_map_in pkm; 2841 #endif 2842 struct mount *mp; 2843 struct vnode *vp; 2844 vm_object_t object; 2845 vm_prot_t maxprot; 2846 boolean_t writecounted; 2847 int error; 2848 2849 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \ 2850 defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) 2851 /* 2852 * POSIX shared-memory objects are defined to have 2853 * kernel persistence, and are not defined to support 2854 * read(2)/write(2) -- or even open(2). Thus, we can 2855 * use MAP_ASYNC to trade on-disk coherence for speed. 2856 * The shm_open(3) library routine turns on the FPOSIXSHM 2857 * flag to request this behavior. 2858 */ 2859 if ((fp->f_flag & FPOSIXSHM) != 0) 2860 flags |= MAP_NOSYNC; 2861 #endif 2862 vp = fp->f_vnode; 2863 2864 /* 2865 * Ensure that file and memory protections are 2866 * compatible. Note that we only worry about 2867 * writability if mapping is shared; in this case, 2868 * current and max prot are dictated by the open file. 2869 * XXX use the vnode instead? Problem is: what 2870 * credentials do we use for determination? What if 2871 * proc does a setuid? 2872 */ 2873 mp = vp->v_mount; 2874 if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) { 2875 maxprot = VM_PROT_NONE; 2876 if ((prot & VM_PROT_EXECUTE) != 0) 2877 return (EACCES); 2878 } else 2879 maxprot = VM_PROT_EXECUTE; 2880 if ((fp->f_flag & FREAD) != 0) 2881 maxprot |= VM_PROT_READ; 2882 else if ((prot & VM_PROT_READ) != 0) 2883 return (EACCES); 2884 2885 /* 2886 * If we are sharing potential changes via MAP_SHARED and we 2887 * are trying to get write permission although we opened it 2888 * without asking for it, bail out. 2889 */ 2890 if ((flags & MAP_SHARED) != 0) { 2891 if ((fp->f_flag & FWRITE) != 0) 2892 maxprot |= VM_PROT_WRITE; 2893 else if ((prot & VM_PROT_WRITE) != 0) 2894 return (EACCES); 2895 } else { 2896 maxprot |= VM_PROT_WRITE; 2897 cap_maxprot |= VM_PROT_WRITE; 2898 } 2899 maxprot &= cap_maxprot; 2900 2901 /* 2902 * For regular files and shared memory, POSIX requires that 2903 * the value of foff be a legitimate offset within the data 2904 * object. In particular, negative offsets are invalid. 2905 * Blocking negative offsets and overflows here avoids 2906 * possible wraparound or user-level access into reserved 2907 * ranges of the data object later. In contrast, POSIX does 2908 * not dictate how offsets are used by device drivers, so in 2909 * the case of a device mapping a negative offset is passed 2910 * on. 2911 */ 2912 if ( 2913 #ifdef _LP64 2914 size > OFF_MAX || 2915 #endif 2916 foff > OFF_MAX - size) 2917 return (EINVAL); 2918 2919 writecounted = FALSE; 2920 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp, 2921 &foff, &object, &writecounted); 2922 if (error != 0) 2923 return (error); 2924 error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object, 2925 foff, writecounted, td); 2926 if (error != 0) { 2927 /* 2928 * If this mapping was accounted for in the vnode's 2929 * writecount, then undo that now. 2930 */ 2931 if (writecounted) 2932 vm_pager_release_writecount(object, 0, size); 2933 vm_object_deallocate(object); 2934 } 2935 #ifdef HWPMC_HOOKS 2936 /* Inform hwpmc(4) if an executable is being mapped. */ 2937 if (PMC_HOOK_INSTALLED(PMC_FN_MMAP)) { 2938 if ((prot & VM_PROT_EXECUTE) != 0 && error == 0) { 2939 pkm.pm_file = vp; 2940 pkm.pm_address = (uintptr_t) *addr; 2941 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_MMAP, (void *) &pkm); 2942 } 2943 } 2944 #endif 2945 return (error); 2946 } 2947 2948 void 2949 vn_fsid(struct vnode *vp, struct vattr *va) 2950 { 2951 fsid_t *f; 2952 2953 f = &vp->v_mount->mnt_stat.f_fsid; 2954 va->va_fsid = (uint32_t)f->val[1]; 2955 va->va_fsid <<= sizeof(f->val[1]) * NBBY; 2956 va->va_fsid += (uint32_t)f->val[0]; 2957 } 2958 2959 int 2960 vn_fsync_buf(struct vnode *vp, int waitfor) 2961 { 2962 struct buf *bp, *nbp; 2963 struct bufobj *bo; 2964 struct mount *mp; 2965 int error, maxretry; 2966 2967 error = 0; 2968 maxretry = 10000; /* large, arbitrarily chosen */ 2969 mp = NULL; 2970 if (vp->v_type == VCHR) { 2971 VI_LOCK(vp); 2972 mp = vp->v_rdev->si_mountpt; 2973 VI_UNLOCK(vp); 2974 } 2975 bo = &vp->v_bufobj; 2976 BO_LOCK(bo); 2977 loop1: 2978 /* 2979 * MARK/SCAN initialization to avoid infinite loops. 2980 */ 2981 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) { 2982 bp->b_vflags &= ~BV_SCANNED; 2983 bp->b_error = 0; 2984 } 2985 2986 /* 2987 * Flush all dirty buffers associated with a vnode. 2988 */ 2989 loop2: 2990 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) { 2991 if ((bp->b_vflags & BV_SCANNED) != 0) 2992 continue; 2993 bp->b_vflags |= BV_SCANNED; 2994 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL)) { 2995 if (waitfor != MNT_WAIT) 2996 continue; 2997 if (BUF_LOCK(bp, 2998 LK_EXCLUSIVE | LK_INTERLOCK | LK_SLEEPFAIL, 2999 BO_LOCKPTR(bo)) != 0) { 3000 BO_LOCK(bo); 3001 goto loop1; 3002 } 3003 BO_LOCK(bo); 3004 } 3005 BO_UNLOCK(bo); 3006 KASSERT(bp->b_bufobj == bo, 3007 ("bp %p wrong b_bufobj %p should be %p", 3008 bp, bp->b_bufobj, bo)); 3009 if ((bp->b_flags & B_DELWRI) == 0) 3010 panic("fsync: not dirty"); 3011 if ((vp->v_object != NULL) && (bp->b_flags & B_CLUSTEROK)) { 3012 vfs_bio_awrite(bp); 3013 } else { 3014 bremfree(bp); 3015 bawrite(bp); 3016 } 3017 if (maxretry < 1000) 3018 pause("dirty", hz < 1000 ? 1 : hz / 1000); 3019 BO_LOCK(bo); 3020 goto loop2; 3021 } 3022 3023 /* 3024 * If synchronous the caller expects us to completely resolve all 3025 * dirty buffers in the system. Wait for in-progress I/O to 3026 * complete (which could include background bitmap writes), then 3027 * retry if dirty blocks still exist. 3028 */ 3029 if (waitfor == MNT_WAIT) { 3030 bufobj_wwait(bo, 0, 0); 3031 if (bo->bo_dirty.bv_cnt > 0) { 3032 /* 3033 * If we are unable to write any of these buffers 3034 * then we fail now rather than trying endlessly 3035 * to write them out. 3036 */ 3037 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) 3038 if ((error = bp->b_error) != 0) 3039 break; 3040 if ((mp != NULL && mp->mnt_secondary_writes > 0) || 3041 (error == 0 && --maxretry >= 0)) 3042 goto loop1; 3043 if (error == 0) 3044 error = EAGAIN; 3045 } 3046 } 3047 BO_UNLOCK(bo); 3048 if (error != 0) 3049 vn_printf(vp, "fsync: giving up on dirty (error = %d) ", error); 3050 3051 return (error); 3052 } 3053 3054 /* 3055 * Copies a byte range from invp to outvp. Calls VOP_COPY_FILE_RANGE() 3056 * or vn_generic_copy_file_range() after rangelocking the byte ranges, 3057 * to do the actual copy. 3058 * vn_generic_copy_file_range() is factored out, so it can be called 3059 * from a VOP_COPY_FILE_RANGE() call as well, but handles vnodes from 3060 * different file systems. 3061 */ 3062 int 3063 vn_copy_file_range(struct vnode *invp, off_t *inoffp, struct vnode *outvp, 3064 off_t *outoffp, size_t *lenp, unsigned int flags, struct ucred *incred, 3065 struct ucred *outcred, struct thread *fsize_td) 3066 { 3067 struct mount *inmp, *outmp; 3068 struct vnode *invpl, *outvpl; 3069 int error; 3070 size_t len; 3071 uint64_t uval; 3072 3073 invpl = outvpl = NULL; 3074 len = *lenp; 3075 *lenp = 0; /* For error returns. */ 3076 error = 0; 3077 3078 /* Do some sanity checks on the arguments. */ 3079 if (invp->v_type == VDIR || outvp->v_type == VDIR) 3080 error = EISDIR; 3081 else if (*inoffp < 0 || *outoffp < 0 || 3082 invp->v_type != VREG || outvp->v_type != VREG) 3083 error = EINVAL; 3084 if (error != 0) 3085 goto out; 3086 3087 /* Ensure offset + len does not wrap around. */ 3088 uval = *inoffp; 3089 uval += len; 3090 if (uval > INT64_MAX) 3091 len = INT64_MAX - *inoffp; 3092 uval = *outoffp; 3093 uval += len; 3094 if (uval > INT64_MAX) 3095 len = INT64_MAX - *outoffp; 3096 if (len == 0) 3097 goto out; 3098 3099 error = VOP_GETLOWVNODE(invp, &invpl, FREAD); 3100 if (error != 0) 3101 goto out; 3102 error = VOP_GETLOWVNODE(outvp, &outvpl, FWRITE); 3103 if (error != 0) 3104 goto out1; 3105 3106 inmp = invpl->v_mount; 3107 outmp = outvpl->v_mount; 3108 if (inmp == NULL || outmp == NULL) 3109 goto out2; 3110 3111 for (;;) { 3112 error = vfs_busy(inmp, 0); 3113 if (error != 0) 3114 goto out2; 3115 if (inmp == outmp) 3116 break; 3117 error = vfs_busy(outmp, MBF_NOWAIT); 3118 if (error != 0) { 3119 vfs_unbusy(inmp); 3120 error = vfs_busy(outmp, 0); 3121 if (error == 0) { 3122 vfs_unbusy(outmp); 3123 continue; 3124 } 3125 goto out2; 3126 } 3127 break; 3128 } 3129 3130 /* 3131 * If the two vnodes are for the same file system type, call 3132 * VOP_COPY_FILE_RANGE(), otherwise call vn_generic_copy_file_range() 3133 * which can handle copies across multiple file system types. 3134 */ 3135 *lenp = len; 3136 if (inmp == outmp || inmp->mnt_vfc == outmp->mnt_vfc) 3137 error = VOP_COPY_FILE_RANGE(invpl, inoffp, outvpl, outoffp, 3138 lenp, flags, incred, outcred, fsize_td); 3139 else 3140 error = ENOSYS; 3141 if (error == ENOSYS) 3142 error = vn_generic_copy_file_range(invpl, inoffp, outvpl, 3143 outoffp, lenp, flags, incred, outcred, fsize_td); 3144 vfs_unbusy(outmp); 3145 if (inmp != outmp) 3146 vfs_unbusy(inmp); 3147 out2: 3148 if (outvpl != NULL) 3149 vrele(outvpl); 3150 out1: 3151 if (invpl != NULL) 3152 vrele(invpl); 3153 out: 3154 return (error); 3155 } 3156 3157 /* 3158 * Test len bytes of data starting at dat for all bytes == 0. 3159 * Return true if all bytes are zero, false otherwise. 3160 * Expects dat to be well aligned. 3161 */ 3162 static bool 3163 mem_iszero(void *dat, int len) 3164 { 3165 int i; 3166 const u_int *p; 3167 const char *cp; 3168 3169 for (p = dat; len > 0; len -= sizeof(*p), p++) { 3170 if (len >= sizeof(*p)) { 3171 if (*p != 0) 3172 return (false); 3173 } else { 3174 cp = (const char *)p; 3175 for (i = 0; i < len; i++, cp++) 3176 if (*cp != '\0') 3177 return (false); 3178 } 3179 } 3180 return (true); 3181 } 3182 3183 /* 3184 * Look for a hole in the output file and, if found, adjust *outoffp 3185 * and *xferp to skip past the hole. 3186 * *xferp is the entire hole length to be written and xfer2 is how many bytes 3187 * to be written as 0's upon return. 3188 */ 3189 static off_t 3190 vn_skip_hole(struct vnode *outvp, off_t xfer2, off_t *outoffp, off_t *xferp, 3191 off_t *dataoffp, off_t *holeoffp, struct ucred *cred) 3192 { 3193 int error; 3194 off_t delta; 3195 3196 if (*holeoffp == 0 || *holeoffp <= *outoffp) { 3197 *dataoffp = *outoffp; 3198 error = VOP_IOCTL(outvp, FIOSEEKDATA, dataoffp, 0, cred, 3199 curthread); 3200 if (error == 0) { 3201 *holeoffp = *dataoffp; 3202 error = VOP_IOCTL(outvp, FIOSEEKHOLE, holeoffp, 0, cred, 3203 curthread); 3204 } 3205 if (error != 0 || *holeoffp == *dataoffp) { 3206 /* 3207 * Since outvp is unlocked, it may be possible for 3208 * another thread to do a truncate(), lseek(), write() 3209 * creating a hole at startoff between the above 3210 * VOP_IOCTL() calls, if the other thread does not do 3211 * rangelocking. 3212 * If that happens, *holeoffp == *dataoffp and finding 3213 * the hole has failed, so disable vn_skip_hole(). 3214 */ 3215 *holeoffp = -1; /* Disable use of vn_skip_hole(). */ 3216 return (xfer2); 3217 } 3218 KASSERT(*dataoffp >= *outoffp, 3219 ("vn_skip_hole: dataoff=%jd < outoff=%jd", 3220 (intmax_t)*dataoffp, (intmax_t)*outoffp)); 3221 KASSERT(*holeoffp > *dataoffp, 3222 ("vn_skip_hole: holeoff=%jd <= dataoff=%jd", 3223 (intmax_t)*holeoffp, (intmax_t)*dataoffp)); 3224 } 3225 3226 /* 3227 * If there is a hole before the data starts, advance *outoffp and 3228 * *xferp past the hole. 3229 */ 3230 if (*dataoffp > *outoffp) { 3231 delta = *dataoffp - *outoffp; 3232 if (delta >= *xferp) { 3233 /* Entire *xferp is a hole. */ 3234 *outoffp += *xferp; 3235 *xferp = 0; 3236 return (0); 3237 } 3238 *xferp -= delta; 3239 *outoffp += delta; 3240 xfer2 = MIN(xfer2, *xferp); 3241 } 3242 3243 /* 3244 * If a hole starts before the end of this xfer2, reduce this xfer2 so 3245 * that the write ends at the start of the hole. 3246 * *holeoffp should always be greater than *outoffp, but for the 3247 * non-INVARIANTS case, check this to make sure xfer2 remains a sane 3248 * value. 3249 */ 3250 if (*holeoffp > *outoffp && *holeoffp < *outoffp + xfer2) 3251 xfer2 = *holeoffp - *outoffp; 3252 return (xfer2); 3253 } 3254 3255 /* 3256 * Write an xfer sized chunk to outvp in blksize blocks from dat. 3257 * dat is a maximum of blksize in length and can be written repeatedly in 3258 * the chunk. 3259 * If growfile == true, just grow the file via vn_truncate_locked() instead 3260 * of doing actual writes. 3261 * If checkhole == true, a hole is being punched, so skip over any hole 3262 * already in the output file. 3263 */ 3264 static int 3265 vn_write_outvp(struct vnode *outvp, char *dat, off_t outoff, off_t xfer, 3266 u_long blksize, bool growfile, bool checkhole, struct ucred *cred) 3267 { 3268 struct mount *mp; 3269 off_t dataoff, holeoff, xfer2; 3270 int error; 3271 3272 /* 3273 * Loop around doing writes of blksize until write has been completed. 3274 * Lock/unlock on each loop iteration so that a bwillwrite() can be 3275 * done for each iteration, since the xfer argument can be very 3276 * large if there is a large hole to punch in the output file. 3277 */ 3278 error = 0; 3279 holeoff = 0; 3280 do { 3281 xfer2 = MIN(xfer, blksize); 3282 if (checkhole) { 3283 /* 3284 * Punching a hole. Skip writing if there is 3285 * already a hole in the output file. 3286 */ 3287 xfer2 = vn_skip_hole(outvp, xfer2, &outoff, &xfer, 3288 &dataoff, &holeoff, cred); 3289 if (xfer == 0) 3290 break; 3291 if (holeoff < 0) 3292 checkhole = false; 3293 KASSERT(xfer2 > 0, ("vn_write_outvp: xfer2=%jd", 3294 (intmax_t)xfer2)); 3295 } 3296 bwillwrite(); 3297 mp = NULL; 3298 error = vn_start_write(outvp, &mp, V_WAIT); 3299 if (error != 0) 3300 break; 3301 if (growfile) { 3302 error = vn_lock(outvp, LK_EXCLUSIVE); 3303 if (error == 0) { 3304 error = vn_truncate_locked(outvp, outoff + xfer, 3305 false, cred); 3306 VOP_UNLOCK(outvp); 3307 } 3308 } else { 3309 error = vn_lock(outvp, vn_lktype_write(mp, outvp)); 3310 if (error == 0) { 3311 error = vn_rdwr(UIO_WRITE, outvp, dat, xfer2, 3312 outoff, UIO_SYSSPACE, IO_NODELOCKED, 3313 curthread->td_ucred, cred, NULL, curthread); 3314 outoff += xfer2; 3315 xfer -= xfer2; 3316 VOP_UNLOCK(outvp); 3317 } 3318 } 3319 if (mp != NULL) 3320 vn_finished_write(mp); 3321 } while (!growfile && xfer > 0 && error == 0); 3322 return (error); 3323 } 3324 3325 /* 3326 * Copy a byte range of one file to another. This function can handle the 3327 * case where invp and outvp are on different file systems. 3328 * It can also be called by a VOP_COPY_FILE_RANGE() to do the work, if there 3329 * is no better file system specific way to do it. 3330 */ 3331 int 3332 vn_generic_copy_file_range(struct vnode *invp, off_t *inoffp, 3333 struct vnode *outvp, off_t *outoffp, size_t *lenp, unsigned int flags, 3334 struct ucred *incred, struct ucred *outcred, struct thread *fsize_td) 3335 { 3336 struct mount *mp; 3337 off_t startoff, endoff, xfer, xfer2; 3338 u_long blksize; 3339 int error, interrupted; 3340 bool cantseek, readzeros, eof, lastblock, holetoeof; 3341 ssize_t aresid, r = 0; 3342 size_t copylen, len, savlen; 3343 off_t insize, outsize; 3344 char *dat; 3345 long holein, holeout; 3346 struct timespec curts, endts; 3347 3348 holein = holeout = 0; 3349 savlen = len = *lenp; 3350 error = 0; 3351 interrupted = 0; 3352 dat = NULL; 3353 3354 error = vn_lock(invp, LK_SHARED); 3355 if (error != 0) 3356 goto out; 3357 if (VOP_PATHCONF(invp, _PC_MIN_HOLE_SIZE, &holein) != 0) 3358 holein = 0; 3359 error = vn_getsize_locked(invp, &insize, incred); 3360 VOP_UNLOCK(invp); 3361 if (error != 0) 3362 goto out; 3363 3364 mp = NULL; 3365 error = vn_start_write(outvp, &mp, V_WAIT); 3366 if (error == 0) 3367 error = vn_lock(outvp, LK_EXCLUSIVE); 3368 if (error == 0) { 3369 /* 3370 * If fsize_td != NULL, do a vn_rlimit_fsizex() call, 3371 * now that outvp is locked. 3372 */ 3373 if (fsize_td != NULL) { 3374 struct uio io; 3375 3376 io.uio_offset = *outoffp; 3377 io.uio_resid = len; 3378 error = vn_rlimit_fsizex(outvp, &io, 0, &r, fsize_td); 3379 len = savlen = io.uio_resid; 3380 /* 3381 * No need to call vn_rlimit_fsizex_res before return, 3382 * since the uio is local. 3383 */ 3384 } 3385 if (VOP_PATHCONF(outvp, _PC_MIN_HOLE_SIZE, &holeout) != 0) 3386 holeout = 0; 3387 /* 3388 * Holes that are past EOF do not need to be written as a block 3389 * of zero bytes. So, truncate the output file as far as 3390 * possible and then use size to decide if writing 0 3391 * bytes is necessary in the loop below. 3392 */ 3393 if (error == 0) 3394 error = vn_getsize_locked(outvp, &outsize, outcred); 3395 if (error == 0 && outsize > *outoffp && 3396 *outoffp <= OFF_MAX - len && outsize <= *outoffp + len && 3397 *inoffp < insize && 3398 *outoffp <= OFF_MAX - (insize - *inoffp) && 3399 outsize <= *outoffp + (insize - *inoffp)) { 3400 #ifdef MAC 3401 error = mac_vnode_check_write(curthread->td_ucred, 3402 outcred, outvp); 3403 if (error == 0) 3404 #endif 3405 error = vn_truncate_locked(outvp, *outoffp, 3406 false, outcred); 3407 if (error == 0) 3408 outsize = *outoffp; 3409 } 3410 VOP_UNLOCK(outvp); 3411 } 3412 if (mp != NULL) 3413 vn_finished_write(mp); 3414 if (error != 0) 3415 goto out; 3416 3417 if (holein == 0 && holeout > 0) { 3418 /* 3419 * For this special case, the input data will be scanned 3420 * for blocks of all 0 bytes. For these blocks, the 3421 * write can be skipped for the output file to create 3422 * an unallocated region. 3423 * Therefore, use the appropriate size for the output file. 3424 */ 3425 blksize = holeout; 3426 if (blksize <= 512) { 3427 /* 3428 * Use f_iosize, since ZFS reports a _PC_MIN_HOLE_SIZE 3429 * of 512, although it actually only creates 3430 * unallocated regions for blocks >= f_iosize. 3431 */ 3432 blksize = outvp->v_mount->mnt_stat.f_iosize; 3433 } 3434 } else { 3435 /* 3436 * Use the larger of the two f_iosize values. If they are 3437 * not the same size, one will normally be an exact multiple of 3438 * the other, since they are both likely to be a power of 2. 3439 */ 3440 blksize = MAX(invp->v_mount->mnt_stat.f_iosize, 3441 outvp->v_mount->mnt_stat.f_iosize); 3442 } 3443 3444 /* Clip to sane limits. */ 3445 if (blksize < 4096) 3446 blksize = 4096; 3447 else if (blksize > maxphys) 3448 blksize = maxphys; 3449 dat = malloc(blksize, M_TEMP, M_WAITOK); 3450 3451 /* 3452 * If VOP_IOCTL(FIOSEEKHOLE) works for invp, use it and FIOSEEKDATA 3453 * to find holes. Otherwise, just scan the read block for all 0s 3454 * in the inner loop where the data copying is done. 3455 * Note that some file systems such as NFSv3, NFSv4.0 and NFSv4.1 may 3456 * support holes on the server, but do not support FIOSEEKHOLE. 3457 * The kernel flag COPY_FILE_RANGE_TIMEO1SEC is used to indicate 3458 * that this function should return after 1second with a partial 3459 * completion. 3460 */ 3461 if ((flags & COPY_FILE_RANGE_TIMEO1SEC) != 0) { 3462 getnanouptime(&endts); 3463 endts.tv_sec++; 3464 } else 3465 timespecclear(&endts); 3466 holetoeof = eof = false; 3467 while (len > 0 && error == 0 && !eof && interrupted == 0) { 3468 endoff = 0; /* To shut up compilers. */ 3469 cantseek = true; 3470 startoff = *inoffp; 3471 copylen = len; 3472 3473 /* 3474 * Find the next data area. If there is just a hole to EOF, 3475 * FIOSEEKDATA should fail with ENXIO. 3476 * (I do not know if any file system will report a hole to 3477 * EOF via FIOSEEKHOLE, but I am pretty sure FIOSEEKDATA 3478 * will fail for those file systems.) 3479 * 3480 * For input files that don't support FIOSEEKDATA/FIOSEEKHOLE, 3481 * the code just falls through to the inner copy loop. 3482 */ 3483 error = EINVAL; 3484 if (holein > 0) { 3485 error = VOP_IOCTL(invp, FIOSEEKDATA, &startoff, 0, 3486 incred, curthread); 3487 if (error == ENXIO) { 3488 startoff = endoff = insize; 3489 eof = holetoeof = true; 3490 error = 0; 3491 } 3492 } 3493 if (error == 0 && !holetoeof) { 3494 endoff = startoff; 3495 error = VOP_IOCTL(invp, FIOSEEKHOLE, &endoff, 0, 3496 incred, curthread); 3497 /* 3498 * Since invp is unlocked, it may be possible for 3499 * another thread to do a truncate(), lseek(), write() 3500 * creating a hole at startoff between the above 3501 * VOP_IOCTL() calls, if the other thread does not do 3502 * rangelocking. 3503 * If that happens, startoff == endoff and finding 3504 * the hole has failed, so set an error. 3505 */ 3506 if (error == 0 && startoff == endoff) 3507 error = EINVAL; /* Any error. Reset to 0. */ 3508 } 3509 if (error == 0) { 3510 if (startoff > *inoffp) { 3511 /* Found hole before data block. */ 3512 xfer = MIN(startoff - *inoffp, len); 3513 if (*outoffp < outsize) { 3514 /* Must write 0s to punch hole. */ 3515 xfer2 = MIN(outsize - *outoffp, 3516 xfer); 3517 memset(dat, 0, MIN(xfer2, blksize)); 3518 error = vn_write_outvp(outvp, dat, 3519 *outoffp, xfer2, blksize, false, 3520 holeout > 0, outcred); 3521 } 3522 3523 if (error == 0 && *outoffp + xfer > 3524 outsize && (xfer == len || holetoeof)) { 3525 /* Grow output file (hole at end). */ 3526 error = vn_write_outvp(outvp, dat, 3527 *outoffp, xfer, blksize, true, 3528 false, outcred); 3529 } 3530 if (error == 0) { 3531 *inoffp += xfer; 3532 *outoffp += xfer; 3533 len -= xfer; 3534 if (len < savlen) { 3535 interrupted = sig_intr(); 3536 if (timespecisset(&endts) && 3537 interrupted == 0) { 3538 getnanouptime(&curts); 3539 if (timespeccmp(&curts, 3540 &endts, >=)) 3541 interrupted = 3542 EINTR; 3543 } 3544 } 3545 } 3546 } 3547 copylen = MIN(len, endoff - startoff); 3548 cantseek = false; 3549 } else { 3550 cantseek = true; 3551 startoff = *inoffp; 3552 copylen = len; 3553 error = 0; 3554 } 3555 3556 xfer = blksize; 3557 if (cantseek) { 3558 /* 3559 * Set first xfer to end at a block boundary, so that 3560 * holes are more likely detected in the loop below via 3561 * the for all bytes 0 method. 3562 */ 3563 xfer -= (*inoffp % blksize); 3564 } 3565 /* Loop copying the data block. */ 3566 while (copylen > 0 && error == 0 && !eof && interrupted == 0) { 3567 if (copylen < xfer) 3568 xfer = copylen; 3569 error = vn_lock(invp, LK_SHARED); 3570 if (error != 0) 3571 goto out; 3572 error = vn_rdwr(UIO_READ, invp, dat, xfer, 3573 startoff, UIO_SYSSPACE, IO_NODELOCKED, 3574 curthread->td_ucred, incred, &aresid, 3575 curthread); 3576 VOP_UNLOCK(invp); 3577 lastblock = false; 3578 if (error == 0 && aresid > 0) { 3579 /* Stop the copy at EOF on the input file. */ 3580 xfer -= aresid; 3581 eof = true; 3582 lastblock = true; 3583 } 3584 if (error == 0) { 3585 /* 3586 * Skip the write for holes past the initial EOF 3587 * of the output file, unless this is the last 3588 * write of the output file at EOF. 3589 */ 3590 readzeros = cantseek ? mem_iszero(dat, xfer) : 3591 false; 3592 if (xfer == len) 3593 lastblock = true; 3594 if (!cantseek || *outoffp < outsize || 3595 lastblock || !readzeros) 3596 error = vn_write_outvp(outvp, dat, 3597 *outoffp, xfer, blksize, 3598 readzeros && lastblock && 3599 *outoffp >= outsize, false, 3600 outcred); 3601 if (error == 0) { 3602 *inoffp += xfer; 3603 startoff += xfer; 3604 *outoffp += xfer; 3605 copylen -= xfer; 3606 len -= xfer; 3607 if (len < savlen) { 3608 interrupted = sig_intr(); 3609 if (timespecisset(&endts) && 3610 interrupted == 0) { 3611 getnanouptime(&curts); 3612 if (timespeccmp(&curts, 3613 &endts, >=)) 3614 interrupted = 3615 EINTR; 3616 } 3617 } 3618 } 3619 } 3620 xfer = blksize; 3621 } 3622 } 3623 out: 3624 *lenp = savlen - len; 3625 free(dat, M_TEMP); 3626 return (error); 3627 } 3628 3629 static int 3630 vn_fallocate(struct file *fp, off_t offset, off_t len, struct thread *td) 3631 { 3632 struct mount *mp; 3633 struct vnode *vp; 3634 off_t olen, ooffset; 3635 int error; 3636 #ifdef AUDIT 3637 int audited_vnode1 = 0; 3638 #endif 3639 3640 vp = fp->f_vnode; 3641 if (vp->v_type != VREG) 3642 return (ENODEV); 3643 3644 /* Allocating blocks may take a long time, so iterate. */ 3645 for (;;) { 3646 olen = len; 3647 ooffset = offset; 3648 3649 bwillwrite(); 3650 mp = NULL; 3651 error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH); 3652 if (error != 0) 3653 break; 3654 error = vn_lock(vp, LK_EXCLUSIVE); 3655 if (error != 0) { 3656 vn_finished_write(mp); 3657 break; 3658 } 3659 #ifdef AUDIT 3660 if (!audited_vnode1) { 3661 AUDIT_ARG_VNODE1(vp); 3662 audited_vnode1 = 1; 3663 } 3664 #endif 3665 #ifdef MAC 3666 error = mac_vnode_check_write(td->td_ucred, fp->f_cred, vp); 3667 if (error == 0) 3668 #endif 3669 error = VOP_ALLOCATE(vp, &offset, &len, 0, 3670 td->td_ucred); 3671 VOP_UNLOCK(vp); 3672 vn_finished_write(mp); 3673 3674 if (olen + ooffset != offset + len) { 3675 panic("offset + len changed from %jx/%jx to %jx/%jx", 3676 ooffset, olen, offset, len); 3677 } 3678 if (error != 0 || len == 0) 3679 break; 3680 KASSERT(olen > len, ("Iteration did not make progress?")); 3681 maybe_yield(); 3682 } 3683 3684 return (error); 3685 } 3686 3687 static int 3688 vn_deallocate_impl(struct vnode *vp, off_t *offset, off_t *length, int flags, 3689 int ioflag, struct ucred *cred, struct ucred *active_cred, 3690 struct ucred *file_cred) 3691 { 3692 struct mount *mp; 3693 void *rl_cookie; 3694 off_t off, len; 3695 int error; 3696 #ifdef AUDIT 3697 bool audited_vnode1 = false; 3698 #endif 3699 3700 rl_cookie = NULL; 3701 error = 0; 3702 mp = NULL; 3703 off = *offset; 3704 len = *length; 3705 3706 if ((ioflag & (IO_NODELOCKED | IO_RANGELOCKED)) == 0) 3707 rl_cookie = vn_rangelock_wlock(vp, off, off + len); 3708 while (len > 0 && error == 0) { 3709 /* 3710 * Try to deallocate the longest range in one pass. 3711 * In case a pass takes too long to be executed, it returns 3712 * partial result. The residue will be proceeded in the next 3713 * pass. 3714 */ 3715 3716 if ((ioflag & IO_NODELOCKED) == 0) { 3717 bwillwrite(); 3718 if ((error = vn_start_write(vp, &mp, 3719 V_WAIT | V_PCATCH)) != 0) 3720 goto out; 3721 vn_lock(vp, vn_lktype_write(mp, vp) | LK_RETRY); 3722 } 3723 #ifdef AUDIT 3724 if (!audited_vnode1) { 3725 AUDIT_ARG_VNODE1(vp); 3726 audited_vnode1 = true; 3727 } 3728 #endif 3729 3730 #ifdef MAC 3731 if ((ioflag & IO_NOMACCHECK) == 0) 3732 error = mac_vnode_check_write(active_cred, file_cred, 3733 vp); 3734 #endif 3735 if (error == 0) 3736 error = VOP_DEALLOCATE(vp, &off, &len, flags, ioflag, 3737 cred); 3738 3739 if ((ioflag & IO_NODELOCKED) == 0) { 3740 VOP_UNLOCK(vp); 3741 if (mp != NULL) { 3742 vn_finished_write(mp); 3743 mp = NULL; 3744 } 3745 } 3746 if (error == 0 && len != 0) 3747 maybe_yield(); 3748 } 3749 out: 3750 if (rl_cookie != NULL) 3751 vn_rangelock_unlock(vp, rl_cookie); 3752 *offset = off; 3753 *length = len; 3754 return (error); 3755 } 3756 3757 /* 3758 * This function is supposed to be used in the situations where the deallocation 3759 * is not triggered by a user request. 3760 */ 3761 int 3762 vn_deallocate(struct vnode *vp, off_t *offset, off_t *length, int flags, 3763 int ioflag, struct ucred *active_cred, struct ucred *file_cred) 3764 { 3765 struct ucred *cred; 3766 3767 if (*offset < 0 || *length <= 0 || *length > OFF_MAX - *offset || 3768 flags != 0) 3769 return (EINVAL); 3770 if (vp->v_type != VREG) 3771 return (ENODEV); 3772 3773 cred = file_cred != NOCRED ? file_cred : active_cred; 3774 return (vn_deallocate_impl(vp, offset, length, flags, ioflag, cred, 3775 active_cred, file_cred)); 3776 } 3777 3778 static int 3779 vn_fspacectl(struct file *fp, int cmd, off_t *offset, off_t *length, int flags, 3780 struct ucred *active_cred, struct thread *td) 3781 { 3782 int error; 3783 struct vnode *vp; 3784 int ioflag; 3785 3786 KASSERT(cmd == SPACECTL_DEALLOC, ("vn_fspacectl: Invalid cmd")); 3787 KASSERT((flags & ~SPACECTL_F_SUPPORTED) == 0, 3788 ("vn_fspacectl: non-zero flags")); 3789 KASSERT(*offset >= 0 && *length > 0 && *length <= OFF_MAX - *offset, 3790 ("vn_fspacectl: offset/length overflow or underflow")); 3791 vp = fp->f_vnode; 3792 3793 if (vp->v_type != VREG) 3794 return (ENODEV); 3795 3796 ioflag = get_write_ioflag(fp); 3797 3798 switch (cmd) { 3799 case SPACECTL_DEALLOC: 3800 error = vn_deallocate_impl(vp, offset, length, flags, ioflag, 3801 active_cred, active_cred, fp->f_cred); 3802 break; 3803 default: 3804 panic("vn_fspacectl: unknown cmd %d", cmd); 3805 } 3806 3807 return (error); 3808 } 3809 3810 /* 3811 * Keep this assert as long as sizeof(struct dirent) is used as the maximum 3812 * entry size. 3813 */ 3814 _Static_assert(_GENERIC_MAXDIRSIZ == sizeof(struct dirent), 3815 "'struct dirent' size must be a multiple of its alignment " 3816 "(see _GENERIC_DIRLEN())"); 3817 3818 /* 3819 * Returns successive directory entries through some caller's provided buffer. 3820 * 3821 * This function automatically refills the provided buffer with calls to 3822 * VOP_READDIR() (after MAC permission checks). 3823 * 3824 * 'td' is used for credentials and passed to uiomove(). 'dirbuf' is the 3825 * caller's buffer to fill and 'dirbuflen' its allocated size. 'dirbuf' must 3826 * be properly aligned to access 'struct dirent' structures and 'dirbuflen' 3827 * must be greater than GENERIC_MAXDIRSIZ to avoid VOP_READDIR() returning 3828 * EINVAL (the latter is not a strong guarantee (yet); but EINVAL will always 3829 * be returned if this requirement is not verified). '*dpp' points to the 3830 * current directory entry in the buffer and '*len' contains the remaining 3831 * valid bytes in 'dirbuf' after 'dpp' (including the pointed entry). 3832 * 3833 * At first call (or when restarting the read), '*len' must have been set to 0, 3834 * '*off' to 0 (or any valid start offset) and '*eofflag' to 0. There are no 3835 * more entries as soon as '*len' is 0 after a call that returned 0. Calling 3836 * again this function after such a condition is considered an error and EINVAL 3837 * will be returned. Other possible error codes are those of VOP_READDIR(), 3838 * EINTEGRITY if the returned entries do not pass coherency tests, or EINVAL 3839 * (bad call). All errors are unrecoverable, i.e., the state ('*len', '*off' 3840 * and '*eofflag') must be re-initialized before a subsequent call. On error 3841 * or at end of directory, '*dpp' is reset to NULL. 3842 * 3843 * '*len', '*off' and '*eofflag' are internal state the caller should not 3844 * tamper with except as explained above. '*off' is the next directory offset 3845 * to read from to refill the buffer. '*eofflag' is set to 0 or 1 by the last 3846 * internal call to VOP_READDIR() that returned without error, indicating 3847 * whether it reached the end of the directory, and to 2 by this function after 3848 * all entries have been read. 3849 */ 3850 int 3851 vn_dir_next_dirent(struct vnode *vp, struct thread *td, 3852 char *dirbuf, size_t dirbuflen, 3853 struct dirent **dpp, size_t *len, off_t *off, int *eofflag) 3854 { 3855 struct dirent *dp = NULL; 3856 int reclen; 3857 int error; 3858 struct uio uio; 3859 struct iovec iov; 3860 3861 ASSERT_VOP_LOCKED(vp, "vnode not locked"); 3862 VNASSERT(vp->v_type == VDIR, vp, ("vnode is not a directory")); 3863 MPASS2((uintptr_t)dirbuf < (uintptr_t)dirbuf + dirbuflen, 3864 "Address space overflow"); 3865 3866 if (__predict_false(dirbuflen < GENERIC_MAXDIRSIZ)) { 3867 /* Don't take any chances in this case */ 3868 error = EINVAL; 3869 goto out; 3870 } 3871 3872 if (*len != 0) { 3873 dp = *dpp; 3874 3875 /* 3876 * The caller continued to call us after an error (we set dp to 3877 * NULL in a previous iteration). Bail out right now. 3878 */ 3879 if (__predict_false(dp == NULL)) 3880 return (EINVAL); 3881 3882 MPASS(*len <= dirbuflen); 3883 MPASS2((uintptr_t)dirbuf <= (uintptr_t)dp && 3884 (uintptr_t)dp + *len <= (uintptr_t)dirbuf + dirbuflen, 3885 "Filled range not inside buffer"); 3886 3887 reclen = dp->d_reclen; 3888 if (reclen >= *len) { 3889 /* End of buffer reached */ 3890 *len = 0; 3891 } else { 3892 dp = (struct dirent *)((char *)dp + reclen); 3893 *len -= reclen; 3894 } 3895 } 3896 3897 if (*len == 0) { 3898 dp = NULL; 3899 3900 /* Have to refill. */ 3901 switch (*eofflag) { 3902 case 0: 3903 break; 3904 3905 case 1: 3906 /* Nothing more to read. */ 3907 *eofflag = 2; /* Remember the caller reached EOF. */ 3908 goto success; 3909 3910 default: 3911 /* The caller didn't test for EOF. */ 3912 error = EINVAL; 3913 goto out; 3914 } 3915 3916 iov.iov_base = dirbuf; 3917 iov.iov_len = dirbuflen; 3918 3919 uio.uio_iov = &iov; 3920 uio.uio_iovcnt = 1; 3921 uio.uio_offset = *off; 3922 uio.uio_resid = dirbuflen; 3923 uio.uio_segflg = UIO_SYSSPACE; 3924 uio.uio_rw = UIO_READ; 3925 uio.uio_td = td; 3926 3927 #ifdef MAC 3928 error = mac_vnode_check_readdir(td->td_ucred, vp); 3929 if (error == 0) 3930 #endif 3931 error = VOP_READDIR(vp, &uio, td->td_ucred, eofflag, 3932 NULL, NULL); 3933 if (error != 0) 3934 goto out; 3935 3936 *len = dirbuflen - uio.uio_resid; 3937 *off = uio.uio_offset; 3938 3939 if (*len == 0) { 3940 /* Sanity check on INVARIANTS. */ 3941 MPASS(*eofflag != 0); 3942 *eofflag = 1; 3943 goto success; 3944 } 3945 3946 /* 3947 * Normalize the flag returned by VOP_READDIR(), since we use 2 3948 * as a sentinel value. 3949 */ 3950 if (*eofflag != 0) 3951 *eofflag = 1; 3952 3953 dp = (struct dirent *)dirbuf; 3954 } 3955 3956 if (__predict_false(*len < GENERIC_MINDIRSIZ || 3957 dp->d_reclen < GENERIC_MINDIRSIZ)) { 3958 error = EINTEGRITY; 3959 dp = NULL; 3960 goto out; 3961 } 3962 3963 success: 3964 error = 0; 3965 out: 3966 *dpp = dp; 3967 return (error); 3968 } 3969 3970 /* 3971 * Checks whether a directory is empty or not. 3972 * 3973 * If the directory is empty, returns 0, and if it is not, ENOTEMPTY. Other 3974 * values are genuine errors preventing the check. 3975 */ 3976 int 3977 vn_dir_check_empty(struct vnode *vp) 3978 { 3979 struct thread *const td = curthread; 3980 char *dirbuf; 3981 size_t dirbuflen, len; 3982 off_t off; 3983 int eofflag, error; 3984 struct dirent *dp; 3985 struct vattr va; 3986 3987 ASSERT_VOP_LOCKED(vp, "vfs_emptydir"); 3988 VNPASS(vp->v_type == VDIR, vp); 3989 3990 error = VOP_GETATTR(vp, &va, td->td_ucred); 3991 if (error != 0) 3992 return (error); 3993 3994 dirbuflen = max(DEV_BSIZE, GENERIC_MAXDIRSIZ); 3995 if (dirbuflen < va.va_blocksize) 3996 dirbuflen = va.va_blocksize; 3997 dirbuf = malloc(dirbuflen, M_TEMP, M_WAITOK); 3998 3999 len = 0; 4000 off = 0; 4001 eofflag = 0; 4002 4003 for (;;) { 4004 error = vn_dir_next_dirent(vp, td, dirbuf, dirbuflen, 4005 &dp, &len, &off, &eofflag); 4006 if (error != 0) 4007 goto end; 4008 4009 if (len == 0) { 4010 /* EOF */ 4011 error = 0; 4012 goto end; 4013 } 4014 4015 /* 4016 * Skip whiteouts. Unionfs operates on filesystems only and 4017 * not on hierarchies, so these whiteouts would be shadowed on 4018 * the system hierarchy but not for a union using the 4019 * filesystem of their directories as the upper layer. 4020 * Additionally, unionfs currently transparently exposes 4021 * union-specific metadata of its upper layer, meaning that 4022 * whiteouts can be seen through the union view in empty 4023 * directories. Taking into account these whiteouts would then 4024 * prevent mounting another filesystem on such effectively 4025 * empty directories. 4026 */ 4027 if (dp->d_type == DT_WHT) 4028 continue; 4029 4030 /* 4031 * Any file in the directory which is not '.' or '..' indicates 4032 * the directory is not empty. 4033 */ 4034 switch (dp->d_namlen) { 4035 case 2: 4036 if (dp->d_name[1] != '.') { 4037 /* Can't be '..' (nor '.') */ 4038 error = ENOTEMPTY; 4039 goto end; 4040 } 4041 /* FALLTHROUGH */ 4042 case 1: 4043 if (dp->d_name[0] != '.') { 4044 /* Can't be '..' nor '.' */ 4045 error = ENOTEMPTY; 4046 goto end; 4047 } 4048 break; 4049 4050 default: 4051 error = ENOTEMPTY; 4052 goto end; 4053 } 4054 } 4055 4056 end: 4057 free(dirbuf, M_TEMP); 4058 return (error); 4059 } 4060 4061 4062 static u_long vn_lock_pair_pause_cnt; 4063 SYSCTL_ULONG(_debug, OID_AUTO, vn_lock_pair_pause, CTLFLAG_RD, 4064 &vn_lock_pair_pause_cnt, 0, 4065 "Count of vn_lock_pair deadlocks"); 4066 4067 u_int vn_lock_pair_pause_max; 4068 SYSCTL_UINT(_debug, OID_AUTO, vn_lock_pair_pause_max, CTLFLAG_RW, 4069 &vn_lock_pair_pause_max, 0, 4070 "Max ticks for vn_lock_pair deadlock avoidance sleep"); 4071 4072 static void 4073 vn_lock_pair_pause(const char *wmesg) 4074 { 4075 atomic_add_long(&vn_lock_pair_pause_cnt, 1); 4076 pause(wmesg, prng32_bounded(vn_lock_pair_pause_max)); 4077 } 4078 4079 /* 4080 * Lock pair of (possibly same) vnodes vp1, vp2, avoiding lock order 4081 * reversal. vp1_locked indicates whether vp1 is locked; if not, vp1 4082 * must be unlocked. Same for vp2 and vp2_locked. One of the vnodes 4083 * can be NULL. 4084 * 4085 * The function returns with both vnodes exclusively or shared locked, 4086 * according to corresponding lkflags, and guarantees that it does not 4087 * create lock order reversal with other threads during its execution. 4088 * Both vnodes could be unlocked temporary (and reclaimed). 4089 * 4090 * If requesting shared locking, locked vnode lock must not be recursed. 4091 * 4092 * Only one of LK_SHARED and LK_EXCLUSIVE must be specified. 4093 * LK_NODDLKTREAT can be optionally passed. 4094 * 4095 * If vp1 == vp2, only one, most exclusive, lock is obtained on it. 4096 */ 4097 void 4098 vn_lock_pair(struct vnode *vp1, bool vp1_locked, int lkflags1, 4099 struct vnode *vp2, bool vp2_locked, int lkflags2) 4100 { 4101 int error, locked1; 4102 4103 MPASS(((lkflags1 & LK_SHARED) != 0) ^ ((lkflags1 & LK_EXCLUSIVE) != 0)); 4104 MPASS((lkflags1 & ~(LK_SHARED | LK_EXCLUSIVE | LK_NODDLKTREAT)) == 0); 4105 MPASS(((lkflags2 & LK_SHARED) != 0) ^ ((lkflags2 & LK_EXCLUSIVE) != 0)); 4106 MPASS((lkflags2 & ~(LK_SHARED | LK_EXCLUSIVE | LK_NODDLKTREAT)) == 0); 4107 4108 if (vp1 == NULL && vp2 == NULL) 4109 return; 4110 4111 if (vp1 == vp2) { 4112 MPASS(vp1_locked == vp2_locked); 4113 4114 /* Select the most exclusive mode for lock. */ 4115 if ((lkflags1 & LK_TYPE_MASK) != (lkflags2 & LK_TYPE_MASK)) 4116 lkflags1 = (lkflags1 & ~LK_SHARED) | LK_EXCLUSIVE; 4117 4118 if (vp1_locked) { 4119 ASSERT_VOP_LOCKED(vp1, "vp1"); 4120 4121 /* No need to relock if any lock is exclusive. */ 4122 if ((vp1->v_vnlock->lock_object.lo_flags & 4123 LK_NOSHARE) != 0) 4124 return; 4125 4126 locked1 = VOP_ISLOCKED(vp1); 4127 if (((lkflags1 & LK_SHARED) != 0 && 4128 locked1 != LK_EXCLUSIVE) || 4129 ((lkflags1 & LK_EXCLUSIVE) != 0 && 4130 locked1 == LK_EXCLUSIVE)) 4131 return; 4132 VOP_UNLOCK(vp1); 4133 } 4134 4135 ASSERT_VOP_UNLOCKED(vp1, "vp1"); 4136 vn_lock(vp1, lkflags1 | LK_RETRY); 4137 return; 4138 } 4139 4140 if (vp1 != NULL) { 4141 if ((lkflags1 & LK_SHARED) != 0 && 4142 (vp1->v_vnlock->lock_object.lo_flags & LK_NOSHARE) != 0) 4143 lkflags1 = (lkflags1 & ~LK_SHARED) | LK_EXCLUSIVE; 4144 if (vp1_locked && VOP_ISLOCKED(vp1) != LK_EXCLUSIVE) { 4145 ASSERT_VOP_LOCKED(vp1, "vp1"); 4146 if ((lkflags1 & LK_EXCLUSIVE) != 0) { 4147 VOP_UNLOCK(vp1); 4148 ASSERT_VOP_UNLOCKED(vp1, 4149 "vp1 shared recursed"); 4150 vp1_locked = false; 4151 } 4152 } else if (!vp1_locked) 4153 ASSERT_VOP_UNLOCKED(vp1, "vp1"); 4154 } else { 4155 vp1_locked = true; 4156 } 4157 4158 if (vp2 != NULL) { 4159 if ((lkflags2 & LK_SHARED) != 0 && 4160 (vp2->v_vnlock->lock_object.lo_flags & LK_NOSHARE) != 0) 4161 lkflags2 = (lkflags2 & ~LK_SHARED) | LK_EXCLUSIVE; 4162 if (vp2_locked && VOP_ISLOCKED(vp2) != LK_EXCLUSIVE) { 4163 ASSERT_VOP_LOCKED(vp2, "vp2"); 4164 if ((lkflags2 & LK_EXCLUSIVE) != 0) { 4165 VOP_UNLOCK(vp2); 4166 ASSERT_VOP_UNLOCKED(vp2, 4167 "vp2 shared recursed"); 4168 vp2_locked = false; 4169 } 4170 } else if (!vp2_locked) 4171 ASSERT_VOP_UNLOCKED(vp2, "vp2"); 4172 } else { 4173 vp2_locked = true; 4174 } 4175 4176 if (!vp1_locked && !vp2_locked) { 4177 vn_lock(vp1, lkflags1 | LK_RETRY); 4178 vp1_locked = true; 4179 } 4180 4181 while (!vp1_locked || !vp2_locked) { 4182 if (vp1_locked && vp2 != NULL) { 4183 if (vp1 != NULL) { 4184 error = VOP_LOCK1(vp2, lkflags2 | LK_NOWAIT, 4185 __FILE__, __LINE__); 4186 if (error == 0) 4187 break; 4188 VOP_UNLOCK(vp1); 4189 vp1_locked = false; 4190 vn_lock_pair_pause("vlp1"); 4191 } 4192 vn_lock(vp2, lkflags2 | LK_RETRY); 4193 vp2_locked = true; 4194 } 4195 if (vp2_locked && vp1 != NULL) { 4196 if (vp2 != NULL) { 4197 error = VOP_LOCK1(vp1, lkflags1 | LK_NOWAIT, 4198 __FILE__, __LINE__); 4199 if (error == 0) 4200 break; 4201 VOP_UNLOCK(vp2); 4202 vp2_locked = false; 4203 vn_lock_pair_pause("vlp2"); 4204 } 4205 vn_lock(vp1, lkflags1 | LK_RETRY); 4206 vp1_locked = true; 4207 } 4208 } 4209 if (vp1 != NULL) { 4210 if (lkflags1 == LK_EXCLUSIVE) 4211 ASSERT_VOP_ELOCKED(vp1, "vp1 ret"); 4212 else 4213 ASSERT_VOP_LOCKED(vp1, "vp1 ret"); 4214 } 4215 if (vp2 != NULL) { 4216 if (lkflags2 == LK_EXCLUSIVE) 4217 ASSERT_VOP_ELOCKED(vp2, "vp2 ret"); 4218 else 4219 ASSERT_VOP_LOCKED(vp2, "vp2 ret"); 4220 } 4221 } 4222 4223 int 4224 vn_lktype_write(struct mount *mp, struct vnode *vp) 4225 { 4226 if (MNT_SHARED_WRITES(mp) || 4227 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) 4228 return (LK_SHARED); 4229 return (LK_EXCLUSIVE); 4230 } 4231