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