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 * @(#)vfs_vnops.c 8.2 (Berkeley) 1/21/94 43 */ 44 45 #include <sys/cdefs.h> 46 __FBSDID("$FreeBSD$"); 47 48 #include "opt_hwpmc_hooks.h" 49 50 #include <sys/param.h> 51 #include <sys/systm.h> 52 #include <sys/disk.h> 53 #include <sys/fail.h> 54 #include <sys/fcntl.h> 55 #include <sys/file.h> 56 #include <sys/kdb.h> 57 #include <sys/ktr.h> 58 #include <sys/stat.h> 59 #include <sys/priv.h> 60 #include <sys/proc.h> 61 #include <sys/limits.h> 62 #include <sys/lock.h> 63 #include <sys/mman.h> 64 #include <sys/mount.h> 65 #include <sys/mutex.h> 66 #include <sys/namei.h> 67 #include <sys/vnode.h> 68 #include <sys/dirent.h> 69 #include <sys/bio.h> 70 #include <sys/buf.h> 71 #include <sys/filio.h> 72 #include <sys/resourcevar.h> 73 #include <sys/rwlock.h> 74 #include <sys/prng.h> 75 #include <sys/sx.h> 76 #include <sys/sleepqueue.h> 77 #include <sys/sysctl.h> 78 #include <sys/ttycom.h> 79 #include <sys/conf.h> 80 #include <sys/syslog.h> 81 #include <sys/unistd.h> 82 #include <sys/user.h> 83 #include <sys/ktrace.h> 84 85 #include <security/audit/audit.h> 86 #include <security/mac/mac_framework.h> 87 88 #include <vm/vm.h> 89 #include <vm/vm_extern.h> 90 #include <vm/pmap.h> 91 #include <vm/vm_map.h> 92 #include <vm/vm_object.h> 93 #include <vm/vm_page.h> 94 #include <vm/vm_pager.h> 95 96 #ifdef HWPMC_HOOKS 97 #include <sys/pmckern.h> 98 #endif 99 100 static fo_rdwr_t vn_read; 101 static fo_rdwr_t vn_write; 102 static fo_rdwr_t vn_io_fault; 103 static fo_truncate_t vn_truncate; 104 static fo_ioctl_t vn_ioctl; 105 static fo_poll_t vn_poll; 106 static fo_kqfilter_t vn_kqfilter; 107 static fo_close_t vn_closefile; 108 static fo_mmap_t vn_mmap; 109 static fo_fallocate_t vn_fallocate; 110 static fo_fspacectl_t vn_fspacectl; 111 112 struct fileops vnops = { 113 .fo_read = vn_io_fault, 114 .fo_write = vn_io_fault, 115 .fo_truncate = vn_truncate, 116 .fo_ioctl = vn_ioctl, 117 .fo_poll = vn_poll, 118 .fo_kqfilter = vn_kqfilter, 119 .fo_stat = vn_statfile, 120 .fo_close = vn_closefile, 121 .fo_chmod = vn_chmod, 122 .fo_chown = vn_chown, 123 .fo_sendfile = vn_sendfile, 124 .fo_seek = vn_seek, 125 .fo_fill_kinfo = vn_fill_kinfo, 126 .fo_mmap = vn_mmap, 127 .fo_fallocate = vn_fallocate, 128 .fo_fspacectl = vn_fspacectl, 129 .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE 130 }; 131 132 const u_int io_hold_cnt = 16; 133 static int vn_io_fault_enable = 1; 134 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RWTUN, 135 &vn_io_fault_enable, 0, "Enable vn_io_fault lock avoidance"); 136 static int vn_io_fault_prefault = 0; 137 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_prefault, CTLFLAG_RWTUN, 138 &vn_io_fault_prefault, 0, "Enable vn_io_fault prefaulting"); 139 static int vn_io_pgcache_read_enable = 1; 140 SYSCTL_INT(_debug, OID_AUTO, vn_io_pgcache_read_enable, CTLFLAG_RWTUN, 141 &vn_io_pgcache_read_enable, 0, 142 "Enable copying from page cache for reads, avoiding fs"); 143 static u_long vn_io_faults_cnt; 144 SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD, 145 &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers"); 146 147 static int vfs_allow_read_dir = 0; 148 SYSCTL_INT(_security_bsd, OID_AUTO, allow_read_dir, CTLFLAG_RW, 149 &vfs_allow_read_dir, 0, 150 "Enable read(2) of directory by root for filesystems that support it"); 151 152 /* 153 * Returns true if vn_io_fault mode of handling the i/o request should 154 * be used. 155 */ 156 static bool 157 do_vn_io_fault(struct vnode *vp, struct uio *uio) 158 { 159 struct mount *mp; 160 161 return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG && 162 (mp = vp->v_mount) != NULL && 163 (mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable); 164 } 165 166 /* 167 * Structure used to pass arguments to vn_io_fault1(), to do either 168 * file- or vnode-based I/O calls. 169 */ 170 struct vn_io_fault_args { 171 enum { 172 VN_IO_FAULT_FOP, 173 VN_IO_FAULT_VOP 174 } kind; 175 struct ucred *cred; 176 int flags; 177 union { 178 struct fop_args_tag { 179 struct file *fp; 180 fo_rdwr_t *doio; 181 } fop_args; 182 struct vop_args_tag { 183 struct vnode *vp; 184 } vop_args; 185 } args; 186 }; 187 188 static int vn_io_fault1(struct vnode *vp, struct uio *uio, 189 struct vn_io_fault_args *args, struct thread *td); 190 191 int 192 vn_open(struct nameidata *ndp, int *flagp, int cmode, struct file *fp) 193 { 194 struct thread *td = curthread; 195 196 return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp)); 197 } 198 199 static uint64_t 200 open2nameif(int fmode, u_int vn_open_flags) 201 { 202 uint64_t res; 203 204 res = ISOPEN | LOCKLEAF; 205 if ((fmode & O_RESOLVE_BENEATH) != 0) 206 res |= RBENEATH; 207 if ((fmode & O_EMPTY_PATH) != 0) 208 res |= EMPTYPATH; 209 if ((fmode & FREAD) != 0) 210 res |= OPENREAD; 211 if ((fmode & FWRITE) != 0) 212 res |= OPENWRITE; 213 if ((vn_open_flags & VN_OPEN_NOAUDIT) == 0) 214 res |= AUDITVNODE1; 215 if ((vn_open_flags & VN_OPEN_NOCAPCHECK) != 0) 216 res |= NOCAPCHECK; 217 if ((vn_open_flags & VN_OPEN_WANTIOCTLCAPS) != 0) 218 res |= WANTIOCTLCAPS; 219 return (res); 220 } 221 222 /* 223 * Common code for vnode open operations via a name lookup. 224 * Lookup the vnode and invoke VOP_CREATE if needed. 225 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 226 * 227 * Note that this does NOT free nameidata for the successful case, 228 * due to the NDINIT being done elsewhere. 229 */ 230 int 231 vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags, 232 struct ucred *cred, struct file *fp) 233 { 234 struct vnode *vp; 235 struct mount *mp; 236 struct vattr vat; 237 struct vattr *vap = &vat; 238 int fmode, error; 239 bool first_open; 240 241 restart: 242 first_open = false; 243 fmode = *flagp; 244 if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT | 245 O_EXCL | O_DIRECTORY) || 246 (fmode & (O_CREAT | O_EMPTY_PATH)) == (O_CREAT | O_EMPTY_PATH)) 247 return (EINVAL); 248 else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) { 249 ndp->ni_cnd.cn_nameiop = CREATE; 250 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags); 251 /* 252 * Set NOCACHE to avoid flushing the cache when 253 * rolling in many files at once. 254 * 255 * Set NC_KEEPPOSENTRY to keep positive entries if they already 256 * exist despite NOCACHE. 257 */ 258 ndp->ni_cnd.cn_flags |= LOCKPARENT | NOCACHE | NC_KEEPPOSENTRY; 259 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 260 ndp->ni_cnd.cn_flags |= FOLLOW; 261 if ((vn_open_flags & VN_OPEN_INVFS) == 0) 262 bwillwrite(); 263 if ((error = namei(ndp)) != 0) 264 return (error); 265 if (ndp->ni_vp == NULL) { 266 VATTR_NULL(vap); 267 vap->va_type = VREG; 268 vap->va_mode = cmode; 269 if (fmode & O_EXCL) 270 vap->va_vaflags |= VA_EXCLUSIVE; 271 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) { 272 NDFREE_PNBUF(ndp); 273 vput(ndp->ni_dvp); 274 if ((error = vn_start_write(NULL, &mp, 275 V_XSLEEP | V_PCATCH)) != 0) 276 return (error); 277 NDREINIT(ndp); 278 goto restart; 279 } 280 if ((vn_open_flags & VN_OPEN_NAMECACHE) != 0) 281 ndp->ni_cnd.cn_flags |= MAKEENTRY; 282 #ifdef MAC 283 error = mac_vnode_check_create(cred, ndp->ni_dvp, 284 &ndp->ni_cnd, vap); 285 if (error == 0) 286 #endif 287 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 288 &ndp->ni_cnd, vap); 289 vp = ndp->ni_vp; 290 if (error == 0 && (fmode & O_EXCL) != 0 && 291 (fmode & (O_EXLOCK | O_SHLOCK)) != 0) { 292 VI_LOCK(vp); 293 vp->v_iflag |= VI_FOPENING; 294 VI_UNLOCK(vp); 295 first_open = true; 296 } 297 VOP_VPUT_PAIR(ndp->ni_dvp, error == 0 ? &vp : NULL, 298 false); 299 vn_finished_write(mp); 300 if (error) { 301 NDFREE_PNBUF(ndp); 302 if (error == ERELOOKUP) { 303 NDREINIT(ndp); 304 goto restart; 305 } 306 return (error); 307 } 308 fmode &= ~O_TRUNC; 309 } else { 310 if (ndp->ni_dvp == ndp->ni_vp) 311 vrele(ndp->ni_dvp); 312 else 313 vput(ndp->ni_dvp); 314 ndp->ni_dvp = NULL; 315 vp = ndp->ni_vp; 316 if (fmode & O_EXCL) { 317 error = EEXIST; 318 goto bad; 319 } 320 if (vp->v_type == VDIR) { 321 error = EISDIR; 322 goto bad; 323 } 324 fmode &= ~O_CREAT; 325 } 326 } else { 327 ndp->ni_cnd.cn_nameiop = LOOKUP; 328 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags); 329 ndp->ni_cnd.cn_flags |= (fmode & O_NOFOLLOW) != 0 ? NOFOLLOW : 330 FOLLOW; 331 if ((fmode & FWRITE) == 0) 332 ndp->ni_cnd.cn_flags |= LOCKSHARED; 333 if ((error = namei(ndp)) != 0) 334 return (error); 335 vp = ndp->ni_vp; 336 } 337 error = vn_open_vnode(vp, fmode, cred, curthread, fp); 338 if (first_open) { 339 VI_LOCK(vp); 340 vp->v_iflag &= ~VI_FOPENING; 341 wakeup(vp); 342 VI_UNLOCK(vp); 343 } 344 if (error) 345 goto bad; 346 *flagp = fmode; 347 return (0); 348 bad: 349 NDFREE_PNBUF(ndp); 350 vput(vp); 351 *flagp = fmode; 352 ndp->ni_vp = NULL; 353 return (error); 354 } 355 356 static int 357 vn_open_vnode_advlock(struct vnode *vp, int fmode, struct file *fp) 358 { 359 struct flock lf; 360 int error, lock_flags, type; 361 362 ASSERT_VOP_LOCKED(vp, "vn_open_vnode_advlock"); 363 if ((fmode & (O_EXLOCK | O_SHLOCK)) == 0) 364 return (0); 365 KASSERT(fp != NULL, ("open with flock requires fp")); 366 if (fp->f_type != DTYPE_NONE && fp->f_type != DTYPE_VNODE) 367 return (EOPNOTSUPP); 368 369 lock_flags = VOP_ISLOCKED(vp); 370 VOP_UNLOCK(vp); 371 372 lf.l_whence = SEEK_SET; 373 lf.l_start = 0; 374 lf.l_len = 0; 375 lf.l_type = (fmode & O_EXLOCK) != 0 ? F_WRLCK : F_RDLCK; 376 type = F_FLOCK; 377 if ((fmode & FNONBLOCK) == 0) 378 type |= F_WAIT; 379 if ((fmode & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL)) 380 type |= F_FIRSTOPEN; 381 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type); 382 if (error == 0) 383 fp->f_flag |= FHASLOCK; 384 385 vn_lock(vp, lock_flags | LK_RETRY); 386 return (error); 387 } 388 389 /* 390 * Common code for vnode open operations once a vnode is located. 391 * Check permissions, and call the VOP_OPEN routine. 392 */ 393 int 394 vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred, 395 struct thread *td, struct file *fp) 396 { 397 accmode_t accmode; 398 int error; 399 400 if (vp->v_type == VLNK) { 401 if ((fmode & O_PATH) == 0 || (fmode & FEXEC) != 0) 402 return (EMLINK); 403 } 404 if (vp->v_type != VDIR && fmode & O_DIRECTORY) 405 return (ENOTDIR); 406 407 accmode = 0; 408 if ((fmode & O_PATH) == 0) { 409 if (vp->v_type == VSOCK) 410 return (EOPNOTSUPP); 411 if ((fmode & (FWRITE | O_TRUNC)) != 0) { 412 if (vp->v_type == VDIR) 413 return (EISDIR); 414 accmode |= VWRITE; 415 } 416 if ((fmode & FREAD) != 0) 417 accmode |= VREAD; 418 if ((fmode & O_APPEND) && (fmode & FWRITE)) 419 accmode |= VAPPEND; 420 #ifdef MAC 421 if ((fmode & O_CREAT) != 0) 422 accmode |= VCREAT; 423 #endif 424 } 425 if ((fmode & FEXEC) != 0) 426 accmode |= VEXEC; 427 #ifdef MAC 428 if ((fmode & O_VERIFY) != 0) 429 accmode |= VVERIFY; 430 error = mac_vnode_check_open(cred, vp, accmode); 431 if (error != 0) 432 return (error); 433 434 accmode &= ~(VCREAT | VVERIFY); 435 #endif 436 if ((fmode & O_CREAT) == 0 && accmode != 0) { 437 error = VOP_ACCESS(vp, accmode, cred, td); 438 if (error != 0) 439 return (error); 440 } 441 if ((fmode & O_PATH) != 0) { 442 if (vp->v_type != VFIFO && vp->v_type != VSOCK && 443 VOP_ACCESS(vp, VREAD, cred, td) == 0) 444 fp->f_flag |= FKQALLOWED; 445 return (0); 446 } 447 448 if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 449 vn_lock(vp, LK_UPGRADE | LK_RETRY); 450 error = VOP_OPEN(vp, fmode, cred, td, fp); 451 if (error != 0) 452 return (error); 453 454 error = vn_open_vnode_advlock(vp, fmode, fp); 455 if (error == 0 && (fmode & FWRITE) != 0) { 456 error = VOP_ADD_WRITECOUNT(vp, 1); 457 if (error == 0) { 458 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 459 __func__, vp, vp->v_writecount); 460 } 461 } 462 463 /* 464 * Error from advlock or VOP_ADD_WRITECOUNT() still requires 465 * calling VOP_CLOSE() to pair with earlier VOP_OPEN(). 466 */ 467 if (error != 0) { 468 if (fp != NULL) { 469 /* 470 * Arrange the call by having fdrop() to use 471 * vn_closefile(). This is to satisfy 472 * filesystems like devfs or tmpfs, which 473 * override fo_close(). 474 */ 475 fp->f_flag |= FOPENFAILED; 476 fp->f_vnode = vp; 477 if (fp->f_ops == &badfileops) { 478 fp->f_type = DTYPE_VNODE; 479 fp->f_ops = &vnops; 480 } 481 vref(vp); 482 } else { 483 /* 484 * If there is no fp, due to kernel-mode open, 485 * we can call VOP_CLOSE() now. 486 */ 487 if ((vp->v_type == VFIFO || 488 !MNT_EXTENDED_SHARED(vp->v_mount)) && 489 VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 490 vn_lock(vp, LK_UPGRADE | LK_RETRY); 491 (void)VOP_CLOSE(vp, fmode & (FREAD | FWRITE | FEXEC), 492 cred, td); 493 } 494 } 495 496 ASSERT_VOP_LOCKED(vp, "vn_open_vnode"); 497 return (error); 498 499 } 500 501 /* 502 * Check for write permissions on the specified vnode. 503 * Prototype text segments cannot be written. 504 * It is racy. 505 */ 506 int 507 vn_writechk(struct vnode *vp) 508 { 509 510 ASSERT_VOP_LOCKED(vp, "vn_writechk"); 511 /* 512 * If there's shared text associated with 513 * the vnode, try to free it up once. If 514 * we fail, we can't allow writing. 515 */ 516 if (VOP_IS_TEXT(vp)) 517 return (ETXTBSY); 518 519 return (0); 520 } 521 522 /* 523 * Vnode close call 524 */ 525 static int 526 vn_close1(struct vnode *vp, int flags, struct ucred *file_cred, 527 struct thread *td, bool keep_ref) 528 { 529 struct mount *mp; 530 int error, lock_flags; 531 532 lock_flags = vp->v_type != VFIFO && MNT_EXTENDED_SHARED(vp->v_mount) ? 533 LK_SHARED : LK_EXCLUSIVE; 534 535 vn_start_write(vp, &mp, V_WAIT); 536 vn_lock(vp, lock_flags | LK_RETRY); 537 AUDIT_ARG_VNODE1(vp); 538 if ((flags & (FWRITE | FOPENFAILED)) == FWRITE) { 539 VOP_ADD_WRITECOUNT_CHECKED(vp, -1); 540 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 541 __func__, vp, vp->v_writecount); 542 } 543 error = VOP_CLOSE(vp, flags, file_cred, td); 544 if (keep_ref) 545 VOP_UNLOCK(vp); 546 else 547 vput(vp); 548 vn_finished_write(mp); 549 return (error); 550 } 551 552 int 553 vn_close(struct vnode *vp, int flags, struct ucred *file_cred, 554 struct thread *td) 555 { 556 557 return (vn_close1(vp, flags, file_cred, td, false)); 558 } 559 560 /* 561 * Heuristic to detect sequential operation. 562 */ 563 static int 564 sequential_heuristic(struct uio *uio, struct file *fp) 565 { 566 enum uio_rw rw; 567 568 ASSERT_VOP_LOCKED(fp->f_vnode, __func__); 569 570 rw = uio->uio_rw; 571 if (fp->f_flag & FRDAHEAD) 572 return (fp->f_seqcount[rw] << IO_SEQSHIFT); 573 574 /* 575 * Offset 0 is handled specially. open() sets f_seqcount to 1 so 576 * that the first I/O is normally considered to be slightly 577 * sequential. Seeking to offset 0 doesn't change sequentiality 578 * unless previous seeks have reduced f_seqcount to 0, in which 579 * case offset 0 is not special. 580 */ 581 if ((uio->uio_offset == 0 && fp->f_seqcount[rw] > 0) || 582 uio->uio_offset == fp->f_nextoff[rw]) { 583 /* 584 * f_seqcount is in units of fixed-size blocks so that it 585 * depends mainly on the amount of sequential I/O and not 586 * much on the number of sequential I/O's. The fixed size 587 * of 16384 is hard-coded here since it is (not quite) just 588 * a magic size that works well here. This size is more 589 * closely related to the best I/O size for real disks than 590 * to any block size used by software. 591 */ 592 if (uio->uio_resid >= IO_SEQMAX * 16384) 593 fp->f_seqcount[rw] = IO_SEQMAX; 594 else { 595 fp->f_seqcount[rw] += howmany(uio->uio_resid, 16384); 596 if (fp->f_seqcount[rw] > IO_SEQMAX) 597 fp->f_seqcount[rw] = IO_SEQMAX; 598 } 599 return (fp->f_seqcount[rw] << IO_SEQSHIFT); 600 } 601 602 /* Not sequential. Quickly draw-down sequentiality. */ 603 if (fp->f_seqcount[rw] > 1) 604 fp->f_seqcount[rw] = 1; 605 else 606 fp->f_seqcount[rw] = 0; 607 return (0); 608 } 609 610 /* 611 * Package up an I/O request on a vnode into a uio and do it. 612 */ 613 int 614 vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset, 615 enum uio_seg segflg, int ioflg, struct ucred *active_cred, 616 struct ucred *file_cred, ssize_t *aresid, struct thread *td) 617 { 618 struct uio auio; 619 struct iovec aiov; 620 struct mount *mp; 621 struct ucred *cred; 622 void *rl_cookie; 623 struct vn_io_fault_args args; 624 int error, lock_flags; 625 626 if (offset < 0 && vp->v_type != VCHR) 627 return (EINVAL); 628 auio.uio_iov = &aiov; 629 auio.uio_iovcnt = 1; 630 aiov.iov_base = base; 631 aiov.iov_len = len; 632 auio.uio_resid = len; 633 auio.uio_offset = offset; 634 auio.uio_segflg = segflg; 635 auio.uio_rw = rw; 636 auio.uio_td = td; 637 error = 0; 638 639 if ((ioflg & IO_NODELOCKED) == 0) { 640 if ((ioflg & IO_RANGELOCKED) == 0) { 641 if (rw == UIO_READ) { 642 rl_cookie = vn_rangelock_rlock(vp, offset, 643 offset + len); 644 } else if ((ioflg & IO_APPEND) != 0) { 645 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 646 } else { 647 rl_cookie = vn_rangelock_wlock(vp, offset, 648 offset + len); 649 } 650 } else 651 rl_cookie = NULL; 652 mp = NULL; 653 if (rw == UIO_WRITE) { 654 if (vp->v_type != VCHR && 655 (error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH)) 656 != 0) 657 goto out; 658 lock_flags = vn_lktype_write(mp, vp); 659 } else 660 lock_flags = LK_SHARED; 661 vn_lock(vp, lock_flags | LK_RETRY); 662 } else 663 rl_cookie = NULL; 664 665 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 666 #ifdef MAC 667 if ((ioflg & IO_NOMACCHECK) == 0) { 668 if (rw == UIO_READ) 669 error = mac_vnode_check_read(active_cred, file_cred, 670 vp); 671 else 672 error = mac_vnode_check_write(active_cred, file_cred, 673 vp); 674 } 675 #endif 676 if (error == 0) { 677 if (file_cred != NULL) 678 cred = file_cred; 679 else 680 cred = active_cred; 681 if (do_vn_io_fault(vp, &auio)) { 682 args.kind = VN_IO_FAULT_VOP; 683 args.cred = cred; 684 args.flags = ioflg; 685 args.args.vop_args.vp = vp; 686 error = vn_io_fault1(vp, &auio, &args, td); 687 } else if (rw == UIO_READ) { 688 error = VOP_READ(vp, &auio, ioflg, cred); 689 } else /* if (rw == UIO_WRITE) */ { 690 error = VOP_WRITE(vp, &auio, ioflg, cred); 691 } 692 } 693 if (aresid) 694 *aresid = auio.uio_resid; 695 else 696 if (auio.uio_resid && error == 0) 697 error = EIO; 698 if ((ioflg & IO_NODELOCKED) == 0) { 699 VOP_UNLOCK(vp); 700 if (mp != NULL) 701 vn_finished_write(mp); 702 } 703 out: 704 if (rl_cookie != NULL) 705 vn_rangelock_unlock(vp, rl_cookie); 706 return (error); 707 } 708 709 /* 710 * Package up an I/O request on a vnode into a uio and do it. The I/O 711 * request is split up into smaller chunks and we try to avoid saturating 712 * the buffer cache while potentially holding a vnode locked, so we 713 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield() 714 * to give other processes a chance to lock the vnode (either other processes 715 * core'ing the same binary, or unrelated processes scanning the directory). 716 */ 717 int 718 vn_rdwr_inchunks(enum uio_rw rw, struct vnode *vp, void *base, size_t len, 719 off_t offset, enum uio_seg segflg, int ioflg, struct ucred *active_cred, 720 struct ucred *file_cred, size_t *aresid, struct thread *td) 721 { 722 int error = 0; 723 ssize_t iaresid; 724 725 do { 726 int chunk; 727 728 /* 729 * Force `offset' to a multiple of MAXBSIZE except possibly 730 * for the first chunk, so that filesystems only need to 731 * write full blocks except possibly for the first and last 732 * chunks. 733 */ 734 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE; 735 736 if (chunk > len) 737 chunk = len; 738 if (rw != UIO_READ && vp->v_type == VREG) 739 bwillwrite(); 740 iaresid = 0; 741 error = vn_rdwr(rw, vp, base, chunk, offset, segflg, 742 ioflg, active_cred, file_cred, &iaresid, td); 743 len -= chunk; /* aresid calc already includes length */ 744 if (error) 745 break; 746 offset += chunk; 747 base = (char *)base + chunk; 748 kern_yield(PRI_USER); 749 } while (len); 750 if (aresid) 751 *aresid = len + iaresid; 752 return (error); 753 } 754 755 #if OFF_MAX <= LONG_MAX 756 off_t 757 foffset_lock(struct file *fp, int flags) 758 { 759 volatile short *flagsp; 760 off_t res; 761 short state; 762 763 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 764 765 if ((flags & FOF_NOLOCK) != 0) 766 return (atomic_load_long(&fp->f_offset)); 767 768 /* 769 * According to McKusick the vn lock was protecting f_offset here. 770 * It is now protected by the FOFFSET_LOCKED flag. 771 */ 772 flagsp = &fp->f_vnread_flags; 773 if (atomic_cmpset_acq_16(flagsp, 0, FOFFSET_LOCKED)) 774 return (atomic_load_long(&fp->f_offset)); 775 776 sleepq_lock(&fp->f_vnread_flags); 777 state = atomic_load_16(flagsp); 778 for (;;) { 779 if ((state & FOFFSET_LOCKED) == 0) { 780 if (!atomic_fcmpset_acq_16(flagsp, &state, 781 FOFFSET_LOCKED)) 782 continue; 783 break; 784 } 785 if ((state & FOFFSET_LOCK_WAITING) == 0) { 786 if (!atomic_fcmpset_acq_16(flagsp, &state, 787 state | FOFFSET_LOCK_WAITING)) 788 continue; 789 } 790 DROP_GIANT(); 791 sleepq_add(&fp->f_vnread_flags, NULL, "vofflock", 0, 0); 792 sleepq_wait(&fp->f_vnread_flags, PUSER -1); 793 PICKUP_GIANT(); 794 sleepq_lock(&fp->f_vnread_flags); 795 state = atomic_load_16(flagsp); 796 } 797 res = atomic_load_long(&fp->f_offset); 798 sleepq_release(&fp->f_vnread_flags); 799 return (res); 800 } 801 802 void 803 foffset_unlock(struct file *fp, off_t val, int flags) 804 { 805 volatile short *flagsp; 806 short state; 807 808 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 809 810 if ((flags & FOF_NOUPDATE) == 0) 811 atomic_store_long(&fp->f_offset, val); 812 if ((flags & FOF_NEXTOFF_R) != 0) 813 fp->f_nextoff[UIO_READ] = val; 814 if ((flags & FOF_NEXTOFF_W) != 0) 815 fp->f_nextoff[UIO_WRITE] = val; 816 817 if ((flags & FOF_NOLOCK) != 0) 818 return; 819 820 flagsp = &fp->f_vnread_flags; 821 state = atomic_load_16(flagsp); 822 if ((state & FOFFSET_LOCK_WAITING) == 0 && 823 atomic_cmpset_rel_16(flagsp, state, 0)) 824 return; 825 826 sleepq_lock(&fp->f_vnread_flags); 827 MPASS((fp->f_vnread_flags & FOFFSET_LOCKED) != 0); 828 MPASS((fp->f_vnread_flags & FOFFSET_LOCK_WAITING) != 0); 829 fp->f_vnread_flags = 0; 830 sleepq_broadcast(&fp->f_vnread_flags, SLEEPQ_SLEEP, 0, 0); 831 sleepq_release(&fp->f_vnread_flags); 832 } 833 #else 834 off_t 835 foffset_lock(struct file *fp, int flags) 836 { 837 struct mtx *mtxp; 838 off_t res; 839 840 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 841 842 mtxp = mtx_pool_find(mtxpool_sleep, fp); 843 mtx_lock(mtxp); 844 if ((flags & FOF_NOLOCK) == 0) { 845 while (fp->f_vnread_flags & FOFFSET_LOCKED) { 846 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING; 847 msleep(&fp->f_vnread_flags, mtxp, PUSER -1, 848 "vofflock", 0); 849 } 850 fp->f_vnread_flags |= FOFFSET_LOCKED; 851 } 852 res = fp->f_offset; 853 mtx_unlock(mtxp); 854 return (res); 855 } 856 857 void 858 foffset_unlock(struct file *fp, off_t val, int flags) 859 { 860 struct mtx *mtxp; 861 862 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 863 864 mtxp = mtx_pool_find(mtxpool_sleep, fp); 865 mtx_lock(mtxp); 866 if ((flags & FOF_NOUPDATE) == 0) 867 fp->f_offset = val; 868 if ((flags & FOF_NEXTOFF_R) != 0) 869 fp->f_nextoff[UIO_READ] = val; 870 if ((flags & FOF_NEXTOFF_W) != 0) 871 fp->f_nextoff[UIO_WRITE] = val; 872 if ((flags & FOF_NOLOCK) == 0) { 873 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0, 874 ("Lost FOFFSET_LOCKED")); 875 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING) 876 wakeup(&fp->f_vnread_flags); 877 fp->f_vnread_flags = 0; 878 } 879 mtx_unlock(mtxp); 880 } 881 #endif 882 883 void 884 foffset_lock_uio(struct file *fp, struct uio *uio, int flags) 885 { 886 887 if ((flags & FOF_OFFSET) == 0) 888 uio->uio_offset = foffset_lock(fp, flags); 889 } 890 891 void 892 foffset_unlock_uio(struct file *fp, struct uio *uio, int flags) 893 { 894 895 if ((flags & FOF_OFFSET) == 0) 896 foffset_unlock(fp, uio->uio_offset, flags); 897 } 898 899 static int 900 get_advice(struct file *fp, struct uio *uio) 901 { 902 struct mtx *mtxp; 903 int ret; 904 905 ret = POSIX_FADV_NORMAL; 906 if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG) 907 return (ret); 908 909 mtxp = mtx_pool_find(mtxpool_sleep, fp); 910 mtx_lock(mtxp); 911 if (fp->f_advice != NULL && 912 uio->uio_offset >= fp->f_advice->fa_start && 913 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end) 914 ret = fp->f_advice->fa_advice; 915 mtx_unlock(mtxp); 916 return (ret); 917 } 918 919 static int 920 get_write_ioflag(struct file *fp) 921 { 922 int ioflag; 923 struct mount *mp; 924 struct vnode *vp; 925 926 ioflag = 0; 927 vp = fp->f_vnode; 928 mp = atomic_load_ptr(&vp->v_mount); 929 930 if ((fp->f_flag & O_DIRECT) != 0) 931 ioflag |= IO_DIRECT; 932 933 if ((fp->f_flag & O_FSYNC) != 0 || 934 (mp != NULL && (mp->mnt_flag & MNT_SYNCHRONOUS) != 0)) 935 ioflag |= IO_SYNC; 936 937 /* 938 * For O_DSYNC we set both IO_SYNC and IO_DATASYNC, so that VOP_WRITE() 939 * or VOP_DEALLOCATE() implementations that don't understand IO_DATASYNC 940 * fall back to full O_SYNC behavior. 941 */ 942 if ((fp->f_flag & O_DSYNC) != 0) 943 ioflag |= IO_SYNC | IO_DATASYNC; 944 945 return (ioflag); 946 } 947 948 int 949 vn_read_from_obj(struct vnode *vp, struct uio *uio) 950 { 951 vm_object_t obj; 952 vm_page_t ma[io_hold_cnt + 2]; 953 off_t off, vsz; 954 ssize_t resid; 955 int error, i, j; 956 957 MPASS(uio->uio_resid <= ptoa(io_hold_cnt + 2)); 958 obj = atomic_load_ptr(&vp->v_object); 959 if (obj == NULL) 960 return (EJUSTRETURN); 961 962 /* 963 * Depends on type stability of vm_objects. 964 */ 965 vm_object_pip_add(obj, 1); 966 if ((obj->flags & OBJ_DEAD) != 0) { 967 /* 968 * Note that object might be already reused from the 969 * vnode, and the OBJ_DEAD flag cleared. This is fine, 970 * we recheck for DOOMED vnode state after all pages 971 * are busied, and retract then. 972 * 973 * But we check for OBJ_DEAD to ensure that we do not 974 * busy pages while vm_object_terminate_pages() 975 * processes the queue. 976 */ 977 error = EJUSTRETURN; 978 goto out_pip; 979 } 980 981 resid = uio->uio_resid; 982 off = uio->uio_offset; 983 for (i = 0; resid > 0; i++) { 984 MPASS(i < io_hold_cnt + 2); 985 ma[i] = vm_page_grab_unlocked(obj, atop(off), 986 VM_ALLOC_NOCREAT | VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY | 987 VM_ALLOC_NOWAIT); 988 if (ma[i] == NULL) 989 break; 990 991 /* 992 * Skip invalid pages. Valid mask can be partial only 993 * at EOF, and we clip later. 994 */ 995 if (vm_page_none_valid(ma[i])) { 996 vm_page_sunbusy(ma[i]); 997 break; 998 } 999 1000 resid -= PAGE_SIZE; 1001 off += PAGE_SIZE; 1002 } 1003 if (i == 0) { 1004 error = EJUSTRETURN; 1005 goto out_pip; 1006 } 1007 1008 /* 1009 * Check VIRF_DOOMED after we busied our pages. Since 1010 * vgonel() terminates the vnode' vm_object, it cannot 1011 * process past pages busied by us. 1012 */ 1013 if (VN_IS_DOOMED(vp)) { 1014 error = EJUSTRETURN; 1015 goto out; 1016 } 1017 1018 resid = PAGE_SIZE - (uio->uio_offset & PAGE_MASK) + ptoa(i - 1); 1019 if (resid > uio->uio_resid) 1020 resid = uio->uio_resid; 1021 1022 /* 1023 * Unlocked read of vnp_size is safe because truncation cannot 1024 * pass busied page. But we load vnp_size into a local 1025 * variable so that possible concurrent extension does not 1026 * break calculation. 1027 */ 1028 #if defined(__powerpc__) && !defined(__powerpc64__) 1029 vsz = obj->un_pager.vnp.vnp_size; 1030 #else 1031 vsz = atomic_load_64(&obj->un_pager.vnp.vnp_size); 1032 #endif 1033 if (uio->uio_offset >= vsz) { 1034 error = EJUSTRETURN; 1035 goto out; 1036 } 1037 if (uio->uio_offset + resid > vsz) 1038 resid = vsz - uio->uio_offset; 1039 1040 error = vn_io_fault_pgmove(ma, uio->uio_offset & PAGE_MASK, resid, uio); 1041 1042 out: 1043 for (j = 0; j < i; j++) { 1044 if (error == 0) 1045 vm_page_reference(ma[j]); 1046 vm_page_sunbusy(ma[j]); 1047 } 1048 out_pip: 1049 vm_object_pip_wakeup(obj); 1050 if (error != 0) 1051 return (error); 1052 return (uio->uio_resid == 0 ? 0 : EJUSTRETURN); 1053 } 1054 1055 /* 1056 * File table vnode read routine. 1057 */ 1058 static int 1059 vn_read(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, 1060 struct thread *td) 1061 { 1062 struct vnode *vp; 1063 off_t orig_offset; 1064 int error, ioflag; 1065 int advice; 1066 1067 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 1068 uio->uio_td, td)); 1069 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 1070 vp = fp->f_vnode; 1071 ioflag = 0; 1072 if (fp->f_flag & FNONBLOCK) 1073 ioflag |= IO_NDELAY; 1074 if (fp->f_flag & O_DIRECT) 1075 ioflag |= IO_DIRECT; 1076 1077 /* 1078 * Try to read from page cache. VIRF_DOOMED check is racy but 1079 * allows us to avoid unneeded work outright. 1080 */ 1081 if (vn_io_pgcache_read_enable && !mac_vnode_check_read_enabled() && 1082 (vn_irflag_read(vp) & (VIRF_DOOMED | VIRF_PGREAD)) == VIRF_PGREAD) { 1083 error = VOP_READ_PGCACHE(vp, uio, ioflag, fp->f_cred); 1084 if (error == 0) { 1085 fp->f_nextoff[UIO_READ] = uio->uio_offset; 1086 return (0); 1087 } 1088 if (error != EJUSTRETURN) 1089 return (error); 1090 } 1091 1092 advice = get_advice(fp, uio); 1093 vn_lock(vp, LK_SHARED | LK_RETRY); 1094 1095 switch (advice) { 1096 case POSIX_FADV_NORMAL: 1097 case POSIX_FADV_SEQUENTIAL: 1098 case POSIX_FADV_NOREUSE: 1099 ioflag |= sequential_heuristic(uio, fp); 1100 break; 1101 case POSIX_FADV_RANDOM: 1102 /* Disable read-ahead for random I/O. */ 1103 break; 1104 } 1105 orig_offset = uio->uio_offset; 1106 1107 #ifdef MAC 1108 error = mac_vnode_check_read(active_cred, fp->f_cred, vp); 1109 if (error == 0) 1110 #endif 1111 error = VOP_READ(vp, uio, ioflag, fp->f_cred); 1112 fp->f_nextoff[UIO_READ] = uio->uio_offset; 1113 VOP_UNLOCK(vp); 1114 if (error == 0 && advice == POSIX_FADV_NOREUSE && 1115 orig_offset != uio->uio_offset) 1116 /* 1117 * Use POSIX_FADV_DONTNEED to flush pages and buffers 1118 * for the backing file after a POSIX_FADV_NOREUSE 1119 * read(2). 1120 */ 1121 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 1122 POSIX_FADV_DONTNEED); 1123 return (error); 1124 } 1125 1126 /* 1127 * File table vnode write routine. 1128 */ 1129 static int 1130 vn_write(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, 1131 struct thread *td) 1132 { 1133 struct vnode *vp; 1134 struct mount *mp; 1135 off_t orig_offset; 1136 int error, ioflag; 1137 int advice; 1138 bool need_finished_write; 1139 1140 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 1141 uio->uio_td, td)); 1142 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 1143 vp = fp->f_vnode; 1144 if (vp->v_type == VREG) 1145 bwillwrite(); 1146 ioflag = IO_UNIT; 1147 if (vp->v_type == VREG && (fp->f_flag & O_APPEND) != 0) 1148 ioflag |= IO_APPEND; 1149 if ((fp->f_flag & FNONBLOCK) != 0) 1150 ioflag |= IO_NDELAY; 1151 ioflag |= get_write_ioflag(fp); 1152 1153 mp = NULL; 1154 need_finished_write = false; 1155 if (vp->v_type != VCHR) { 1156 error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH); 1157 if (error != 0) 1158 goto unlock; 1159 need_finished_write = true; 1160 } 1161 1162 advice = get_advice(fp, uio); 1163 1164 vn_lock(vp, vn_lktype_write(mp, vp) | LK_RETRY); 1165 switch (advice) { 1166 case POSIX_FADV_NORMAL: 1167 case POSIX_FADV_SEQUENTIAL: 1168 case POSIX_FADV_NOREUSE: 1169 ioflag |= sequential_heuristic(uio, fp); 1170 break; 1171 case POSIX_FADV_RANDOM: 1172 /* XXX: Is this correct? */ 1173 break; 1174 } 1175 orig_offset = uio->uio_offset; 1176 1177 #ifdef MAC 1178 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1179 if (error == 0) 1180 #endif 1181 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred); 1182 fp->f_nextoff[UIO_WRITE] = uio->uio_offset; 1183 VOP_UNLOCK(vp); 1184 if (need_finished_write) 1185 vn_finished_write(mp); 1186 if (error == 0 && advice == POSIX_FADV_NOREUSE && 1187 orig_offset != uio->uio_offset) 1188 /* 1189 * Use POSIX_FADV_DONTNEED to flush pages and buffers 1190 * for the backing file after a POSIX_FADV_NOREUSE 1191 * write(2). 1192 */ 1193 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 1194 POSIX_FADV_DONTNEED); 1195 unlock: 1196 return (error); 1197 } 1198 1199 /* 1200 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to 1201 * prevent the following deadlock: 1202 * 1203 * Assume that the thread A reads from the vnode vp1 into userspace 1204 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is 1205 * currently not resident, then system ends up with the call chain 1206 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] -> 1207 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2) 1208 * which establishes lock order vp1->vn_lock, then vp2->vn_lock. 1209 * If, at the same time, thread B reads from vnode vp2 into buffer buf2 1210 * backed by the pages of vnode vp1, and some page in buf2 is not 1211 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock. 1212 * 1213 * To prevent the lock order reversal and deadlock, vn_io_fault() does 1214 * not allow page faults to happen during VOP_READ() or VOP_WRITE(). 1215 * Instead, it first tries to do the whole range i/o with pagefaults 1216 * disabled. If all pages in the i/o buffer are resident and mapped, 1217 * VOP will succeed (ignoring the genuine filesystem errors). 1218 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do 1219 * i/o in chunks, with all pages in the chunk prefaulted and held 1220 * using vm_fault_quick_hold_pages(). 1221 * 1222 * Filesystems using this deadlock avoidance scheme should use the 1223 * array of the held pages from uio, saved in the curthread->td_ma, 1224 * instead of doing uiomove(). A helper function 1225 * vn_io_fault_uiomove() converts uiomove request into 1226 * uiomove_fromphys() over td_ma array. 1227 * 1228 * Since vnode locks do not cover the whole i/o anymore, rangelocks 1229 * make the current i/o request atomic with respect to other i/os and 1230 * truncations. 1231 */ 1232 1233 /* 1234 * Decode vn_io_fault_args and perform the corresponding i/o. 1235 */ 1236 static int 1237 vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio, 1238 struct thread *td) 1239 { 1240 int error, save; 1241 1242 error = 0; 1243 save = vm_fault_disable_pagefaults(); 1244 switch (args->kind) { 1245 case VN_IO_FAULT_FOP: 1246 error = (args->args.fop_args.doio)(args->args.fop_args.fp, 1247 uio, args->cred, args->flags, td); 1248 break; 1249 case VN_IO_FAULT_VOP: 1250 if (uio->uio_rw == UIO_READ) { 1251 error = VOP_READ(args->args.vop_args.vp, uio, 1252 args->flags, args->cred); 1253 } else if (uio->uio_rw == UIO_WRITE) { 1254 error = VOP_WRITE(args->args.vop_args.vp, uio, 1255 args->flags, args->cred); 1256 } 1257 break; 1258 default: 1259 panic("vn_io_fault_doio: unknown kind of io %d %d", 1260 args->kind, uio->uio_rw); 1261 } 1262 vm_fault_enable_pagefaults(save); 1263 return (error); 1264 } 1265 1266 static int 1267 vn_io_fault_touch(char *base, const struct uio *uio) 1268 { 1269 int r; 1270 1271 r = fubyte(base); 1272 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1)) 1273 return (EFAULT); 1274 return (0); 1275 } 1276 1277 static int 1278 vn_io_fault_prefault_user(const struct uio *uio) 1279 { 1280 char *base; 1281 const struct iovec *iov; 1282 size_t len; 1283 ssize_t resid; 1284 int error, i; 1285 1286 KASSERT(uio->uio_segflg == UIO_USERSPACE, 1287 ("vn_io_fault_prefault userspace")); 1288 1289 error = i = 0; 1290 iov = uio->uio_iov; 1291 resid = uio->uio_resid; 1292 base = iov->iov_base; 1293 len = iov->iov_len; 1294 while (resid > 0) { 1295 error = vn_io_fault_touch(base, uio); 1296 if (error != 0) 1297 break; 1298 if (len < PAGE_SIZE) { 1299 if (len != 0) { 1300 error = vn_io_fault_touch(base + len - 1, uio); 1301 if (error != 0) 1302 break; 1303 resid -= len; 1304 } 1305 if (++i >= uio->uio_iovcnt) 1306 break; 1307 iov = uio->uio_iov + i; 1308 base = iov->iov_base; 1309 len = iov->iov_len; 1310 } else { 1311 len -= PAGE_SIZE; 1312 base += PAGE_SIZE; 1313 resid -= PAGE_SIZE; 1314 } 1315 } 1316 return (error); 1317 } 1318 1319 /* 1320 * Common code for vn_io_fault(), agnostic to the kind of i/o request. 1321 * Uses vn_io_fault_doio() to make the call to an actual i/o function. 1322 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request 1323 * into args and call vn_io_fault1() to handle faults during the user 1324 * mode buffer accesses. 1325 */ 1326 static int 1327 vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args, 1328 struct thread *td) 1329 { 1330 vm_page_t ma[io_hold_cnt + 2]; 1331 struct uio *uio_clone, short_uio; 1332 struct iovec short_iovec[1]; 1333 vm_page_t *prev_td_ma; 1334 vm_prot_t prot; 1335 vm_offset_t addr, end; 1336 size_t len, resid; 1337 ssize_t adv; 1338 int error, cnt, saveheld, prev_td_ma_cnt; 1339 1340 if (vn_io_fault_prefault) { 1341 error = vn_io_fault_prefault_user(uio); 1342 if (error != 0) 1343 return (error); /* Or ignore ? */ 1344 } 1345 1346 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ; 1347 1348 /* 1349 * The UFS follows IO_UNIT directive and replays back both 1350 * uio_offset and uio_resid if an error is encountered during the 1351 * operation. But, since the iovec may be already advanced, 1352 * uio is still in an inconsistent state. 1353 * 1354 * Cache a copy of the original uio, which is advanced to the redo 1355 * point using UIO_NOCOPY below. 1356 */ 1357 uio_clone = cloneuio(uio); 1358 resid = uio->uio_resid; 1359 1360 short_uio.uio_segflg = UIO_USERSPACE; 1361 short_uio.uio_rw = uio->uio_rw; 1362 short_uio.uio_td = uio->uio_td; 1363 1364 error = vn_io_fault_doio(args, uio, td); 1365 if (error != EFAULT) 1366 goto out; 1367 1368 atomic_add_long(&vn_io_faults_cnt, 1); 1369 uio_clone->uio_segflg = UIO_NOCOPY; 1370 uiomove(NULL, resid - uio->uio_resid, uio_clone); 1371 uio_clone->uio_segflg = uio->uio_segflg; 1372 1373 saveheld = curthread_pflags_set(TDP_UIOHELD); 1374 prev_td_ma = td->td_ma; 1375 prev_td_ma_cnt = td->td_ma_cnt; 1376 1377 while (uio_clone->uio_resid != 0) { 1378 len = uio_clone->uio_iov->iov_len; 1379 if (len == 0) { 1380 KASSERT(uio_clone->uio_iovcnt >= 1, 1381 ("iovcnt underflow")); 1382 uio_clone->uio_iov++; 1383 uio_clone->uio_iovcnt--; 1384 continue; 1385 } 1386 if (len > ptoa(io_hold_cnt)) 1387 len = ptoa(io_hold_cnt); 1388 addr = (uintptr_t)uio_clone->uio_iov->iov_base; 1389 end = round_page(addr + len); 1390 if (end < addr) { 1391 error = EFAULT; 1392 break; 1393 } 1394 /* 1395 * A perfectly misaligned address and length could cause 1396 * both the start and the end of the chunk to use partial 1397 * page. +2 accounts for such a situation. 1398 */ 1399 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map, 1400 addr, len, prot, ma, io_hold_cnt + 2); 1401 if (cnt == -1) { 1402 error = EFAULT; 1403 break; 1404 } 1405 short_uio.uio_iov = &short_iovec[0]; 1406 short_iovec[0].iov_base = (void *)addr; 1407 short_uio.uio_iovcnt = 1; 1408 short_uio.uio_resid = short_iovec[0].iov_len = len; 1409 short_uio.uio_offset = uio_clone->uio_offset; 1410 td->td_ma = ma; 1411 td->td_ma_cnt = cnt; 1412 1413 error = vn_io_fault_doio(args, &short_uio, td); 1414 vm_page_unhold_pages(ma, cnt); 1415 adv = len - short_uio.uio_resid; 1416 1417 uio_clone->uio_iov->iov_base = 1418 (char *)uio_clone->uio_iov->iov_base + adv; 1419 uio_clone->uio_iov->iov_len -= adv; 1420 uio_clone->uio_resid -= adv; 1421 uio_clone->uio_offset += adv; 1422 1423 uio->uio_resid -= adv; 1424 uio->uio_offset += adv; 1425 1426 if (error != 0 || adv == 0) 1427 break; 1428 } 1429 td->td_ma = prev_td_ma; 1430 td->td_ma_cnt = prev_td_ma_cnt; 1431 curthread_pflags_restore(saveheld); 1432 out: 1433 free(uio_clone, M_IOV); 1434 return (error); 1435 } 1436 1437 static int 1438 vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred, 1439 int flags, struct thread *td) 1440 { 1441 fo_rdwr_t *doio; 1442 struct vnode *vp; 1443 void *rl_cookie; 1444 struct vn_io_fault_args args; 1445 int error; 1446 1447 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write; 1448 vp = fp->f_vnode; 1449 1450 /* 1451 * The ability to read(2) on a directory has historically been 1452 * allowed for all users, but this can and has been the source of 1453 * at least one security issue in the past. As such, it is now hidden 1454 * away behind a sysctl for those that actually need it to use it, and 1455 * restricted to root when it's turned on to make it relatively safe to 1456 * leave on for longer sessions of need. 1457 */ 1458 if (vp->v_type == VDIR) { 1459 KASSERT(uio->uio_rw == UIO_READ, 1460 ("illegal write attempted on a directory")); 1461 if (!vfs_allow_read_dir) 1462 return (EISDIR); 1463 if ((error = priv_check(td, PRIV_VFS_READ_DIR)) != 0) 1464 return (EISDIR); 1465 } 1466 1467 foffset_lock_uio(fp, uio, flags); 1468 if (do_vn_io_fault(vp, uio)) { 1469 args.kind = VN_IO_FAULT_FOP; 1470 args.args.fop_args.fp = fp; 1471 args.args.fop_args.doio = doio; 1472 args.cred = active_cred; 1473 args.flags = flags | FOF_OFFSET; 1474 if (uio->uio_rw == UIO_READ) { 1475 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset, 1476 uio->uio_offset + uio->uio_resid); 1477 } else if ((fp->f_flag & O_APPEND) != 0 || 1478 (flags & FOF_OFFSET) == 0) { 1479 /* For appenders, punt and lock the whole range. */ 1480 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1481 } else { 1482 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset, 1483 uio->uio_offset + uio->uio_resid); 1484 } 1485 error = vn_io_fault1(vp, uio, &args, td); 1486 vn_rangelock_unlock(vp, rl_cookie); 1487 } else { 1488 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td); 1489 } 1490 foffset_unlock_uio(fp, uio, flags); 1491 return (error); 1492 } 1493 1494 /* 1495 * Helper function to perform the requested uiomove operation using 1496 * the held pages for io->uio_iov[0].iov_base buffer instead of 1497 * copyin/copyout. Access to the pages with uiomove_fromphys() 1498 * instead of iov_base prevents page faults that could occur due to 1499 * pmap_collect() invalidating the mapping created by 1500 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or 1501 * object cleanup revoking the write access from page mappings. 1502 * 1503 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove() 1504 * instead of plain uiomove(). 1505 */ 1506 int 1507 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio) 1508 { 1509 struct uio transp_uio; 1510 struct iovec transp_iov[1]; 1511 struct thread *td; 1512 size_t adv; 1513 int error, pgadv; 1514 1515 td = curthread; 1516 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1517 uio->uio_segflg != UIO_USERSPACE) 1518 return (uiomove(data, xfersize, uio)); 1519 1520 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1521 transp_iov[0].iov_base = data; 1522 transp_uio.uio_iov = &transp_iov[0]; 1523 transp_uio.uio_iovcnt = 1; 1524 if (xfersize > uio->uio_resid) 1525 xfersize = uio->uio_resid; 1526 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize; 1527 transp_uio.uio_offset = 0; 1528 transp_uio.uio_segflg = UIO_SYSSPACE; 1529 /* 1530 * Since transp_iov points to data, and td_ma page array 1531 * corresponds to original uio->uio_iov, we need to invert the 1532 * direction of the i/o operation as passed to 1533 * uiomove_fromphys(). 1534 */ 1535 switch (uio->uio_rw) { 1536 case UIO_WRITE: 1537 transp_uio.uio_rw = UIO_READ; 1538 break; 1539 case UIO_READ: 1540 transp_uio.uio_rw = UIO_WRITE; 1541 break; 1542 } 1543 transp_uio.uio_td = uio->uio_td; 1544 error = uiomove_fromphys(td->td_ma, 1545 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK, 1546 xfersize, &transp_uio); 1547 adv = xfersize - transp_uio.uio_resid; 1548 pgadv = 1549 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) - 1550 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT); 1551 td->td_ma += pgadv; 1552 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1553 pgadv)); 1554 td->td_ma_cnt -= pgadv; 1555 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv; 1556 uio->uio_iov->iov_len -= adv; 1557 uio->uio_resid -= adv; 1558 uio->uio_offset += adv; 1559 return (error); 1560 } 1561 1562 int 1563 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize, 1564 struct uio *uio) 1565 { 1566 struct thread *td; 1567 vm_offset_t iov_base; 1568 int cnt, pgadv; 1569 1570 td = curthread; 1571 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1572 uio->uio_segflg != UIO_USERSPACE) 1573 return (uiomove_fromphys(ma, offset, xfersize, uio)); 1574 1575 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1576 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize; 1577 iov_base = (vm_offset_t)uio->uio_iov->iov_base; 1578 switch (uio->uio_rw) { 1579 case UIO_WRITE: 1580 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma, 1581 offset, cnt); 1582 break; 1583 case UIO_READ: 1584 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK, 1585 cnt); 1586 break; 1587 } 1588 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT); 1589 td->td_ma += pgadv; 1590 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1591 pgadv)); 1592 td->td_ma_cnt -= pgadv; 1593 uio->uio_iov->iov_base = (char *)(iov_base + cnt); 1594 uio->uio_iov->iov_len -= cnt; 1595 uio->uio_resid -= cnt; 1596 uio->uio_offset += cnt; 1597 return (0); 1598 } 1599 1600 /* 1601 * File table truncate routine. 1602 */ 1603 static int 1604 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1605 struct thread *td) 1606 { 1607 struct mount *mp; 1608 struct vnode *vp; 1609 void *rl_cookie; 1610 int error; 1611 1612 vp = fp->f_vnode; 1613 1614 retry: 1615 /* 1616 * Lock the whole range for truncation. Otherwise split i/o 1617 * might happen partly before and partly after the truncation. 1618 */ 1619 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1620 error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH); 1621 if (error) 1622 goto out1; 1623 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1624 AUDIT_ARG_VNODE1(vp); 1625 if (vp->v_type == VDIR) { 1626 error = EISDIR; 1627 goto out; 1628 } 1629 #ifdef MAC 1630 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1631 if (error) 1632 goto out; 1633 #endif 1634 error = vn_truncate_locked(vp, length, (fp->f_flag & O_FSYNC) != 0, 1635 fp->f_cred); 1636 out: 1637 VOP_UNLOCK(vp); 1638 vn_finished_write(mp); 1639 out1: 1640 vn_rangelock_unlock(vp, rl_cookie); 1641 if (error == ERELOOKUP) 1642 goto retry; 1643 return (error); 1644 } 1645 1646 /* 1647 * Truncate a file that is already locked. 1648 */ 1649 int 1650 vn_truncate_locked(struct vnode *vp, off_t length, bool sync, 1651 struct ucred *cred) 1652 { 1653 struct vattr vattr; 1654 int error; 1655 1656 error = VOP_ADD_WRITECOUNT(vp, 1); 1657 if (error == 0) { 1658 VATTR_NULL(&vattr); 1659 vattr.va_size = length; 1660 if (sync) 1661 vattr.va_vaflags |= VA_SYNC; 1662 error = VOP_SETATTR(vp, &vattr, cred); 1663 VOP_ADD_WRITECOUNT_CHECKED(vp, -1); 1664 } 1665 return (error); 1666 } 1667 1668 /* 1669 * File table vnode stat routine. 1670 */ 1671 int 1672 vn_statfile(struct file *fp, struct stat *sb, struct ucred *active_cred) 1673 { 1674 struct vnode *vp = fp->f_vnode; 1675 int error; 1676 1677 vn_lock(vp, LK_SHARED | LK_RETRY); 1678 error = VOP_STAT(vp, sb, active_cred, fp->f_cred); 1679 VOP_UNLOCK(vp); 1680 1681 return (error); 1682 } 1683 1684 /* 1685 * File table vnode ioctl routine. 1686 */ 1687 static int 1688 vn_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, 1689 struct thread *td) 1690 { 1691 struct vnode *vp; 1692 struct fiobmap2_arg *bmarg; 1693 off_t size; 1694 int error; 1695 1696 vp = fp->f_vnode; 1697 switch (vp->v_type) { 1698 case VDIR: 1699 case VREG: 1700 switch (com) { 1701 case FIONREAD: 1702 error = vn_getsize(vp, &size, active_cred); 1703 if (error == 0) 1704 *(int *)data = size - fp->f_offset; 1705 return (error); 1706 case FIOBMAP2: 1707 bmarg = (struct fiobmap2_arg *)data; 1708 vn_lock(vp, LK_SHARED | LK_RETRY); 1709 #ifdef MAC 1710 error = mac_vnode_check_read(active_cred, fp->f_cred, 1711 vp); 1712 if (error == 0) 1713 #endif 1714 error = VOP_BMAP(vp, bmarg->bn, NULL, 1715 &bmarg->bn, &bmarg->runp, &bmarg->runb); 1716 VOP_UNLOCK(vp); 1717 return (error); 1718 case FIONBIO: 1719 case FIOASYNC: 1720 return (0); 1721 default: 1722 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1723 active_cred, td)); 1724 } 1725 break; 1726 case VCHR: 1727 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1728 active_cred, td)); 1729 default: 1730 return (ENOTTY); 1731 } 1732 } 1733 1734 /* 1735 * File table vnode poll routine. 1736 */ 1737 static int 1738 vn_poll(struct file *fp, int events, struct ucred *active_cred, 1739 struct thread *td) 1740 { 1741 struct vnode *vp; 1742 int error; 1743 1744 vp = fp->f_vnode; 1745 #if defined(MAC) || defined(AUDIT) 1746 if (AUDITING_TD(td) || mac_vnode_check_poll_enabled()) { 1747 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1748 AUDIT_ARG_VNODE1(vp); 1749 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp); 1750 VOP_UNLOCK(vp); 1751 if (error != 0) 1752 return (error); 1753 } 1754 #endif 1755 error = VOP_POLL(vp, events, fp->f_cred, td); 1756 return (error); 1757 } 1758 1759 /* 1760 * Acquire the requested lock and then check for validity. LK_RETRY 1761 * permits vn_lock to return doomed vnodes. 1762 */ 1763 static int __noinline 1764 _vn_lock_fallback(struct vnode *vp, int flags, const char *file, int line, 1765 int error) 1766 { 1767 1768 KASSERT((flags & LK_RETRY) == 0 || error == 0, 1769 ("vn_lock: error %d incompatible with flags %#x", error, flags)); 1770 1771 if (error == 0) 1772 VNASSERT(VN_IS_DOOMED(vp), vp, ("vnode not doomed")); 1773 1774 if ((flags & LK_RETRY) == 0) { 1775 if (error == 0) { 1776 VOP_UNLOCK(vp); 1777 error = ENOENT; 1778 } 1779 return (error); 1780 } 1781 1782 /* 1783 * LK_RETRY case. 1784 * 1785 * Nothing to do if we got the lock. 1786 */ 1787 if (error == 0) 1788 return (0); 1789 1790 /* 1791 * Interlock was dropped by the call in _vn_lock. 1792 */ 1793 flags &= ~LK_INTERLOCK; 1794 do { 1795 error = VOP_LOCK1(vp, flags, file, line); 1796 } while (error != 0); 1797 return (0); 1798 } 1799 1800 int 1801 _vn_lock(struct vnode *vp, int flags, const char *file, int line) 1802 { 1803 int error; 1804 1805 VNASSERT((flags & LK_TYPE_MASK) != 0, vp, 1806 ("vn_lock: no locktype (%d passed)", flags)); 1807 VNPASS(vp->v_holdcnt > 0, vp); 1808 error = VOP_LOCK1(vp, flags, file, line); 1809 if (__predict_false(error != 0 || VN_IS_DOOMED(vp))) 1810 return (_vn_lock_fallback(vp, flags, file, line, error)); 1811 return (0); 1812 } 1813 1814 /* 1815 * File table vnode close routine. 1816 */ 1817 static int 1818 vn_closefile(struct file *fp, struct thread *td) 1819 { 1820 struct vnode *vp; 1821 struct flock lf; 1822 int error; 1823 bool ref; 1824 1825 vp = fp->f_vnode; 1826 fp->f_ops = &badfileops; 1827 ref = (fp->f_flag & FHASLOCK) != 0; 1828 1829 error = vn_close1(vp, fp->f_flag, fp->f_cred, td, ref); 1830 1831 if (__predict_false(ref)) { 1832 lf.l_whence = SEEK_SET; 1833 lf.l_start = 0; 1834 lf.l_len = 0; 1835 lf.l_type = F_UNLCK; 1836 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK); 1837 vrele(vp); 1838 } 1839 return (error); 1840 } 1841 1842 /* 1843 * Preparing to start a filesystem write operation. If the operation is 1844 * permitted, then we bump the count of operations in progress and 1845 * proceed. If a suspend request is in progress, we wait until the 1846 * suspension is over, and then proceed. 1847 */ 1848 static int 1849 vn_start_write_refed(struct mount *mp, int flags, bool mplocked) 1850 { 1851 struct mount_pcpu *mpcpu; 1852 int error, mflags; 1853 1854 if (__predict_true(!mplocked) && (flags & V_XSLEEP) == 0 && 1855 vfs_op_thread_enter(mp, mpcpu)) { 1856 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 1857 vfs_mp_count_add_pcpu(mpcpu, writeopcount, 1); 1858 vfs_op_thread_exit(mp, mpcpu); 1859 return (0); 1860 } 1861 1862 if (mplocked) 1863 mtx_assert(MNT_MTX(mp), MA_OWNED); 1864 else 1865 MNT_ILOCK(mp); 1866 1867 error = 0; 1868 1869 /* 1870 * Check on status of suspension. 1871 */ 1872 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 || 1873 mp->mnt_susp_owner != curthread) { 1874 mflags = 0; 1875 if ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0) { 1876 if (flags & V_PCATCH) 1877 mflags |= PCATCH; 1878 } 1879 mflags |= (PUSER - 1); 1880 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1881 if ((flags & V_NOWAIT) != 0) { 1882 error = EWOULDBLOCK; 1883 goto unlock; 1884 } 1885 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, 1886 "suspfs", 0); 1887 if (error != 0) 1888 goto unlock; 1889 } 1890 } 1891 if ((flags & V_XSLEEP) != 0) 1892 goto unlock; 1893 mp->mnt_writeopcount++; 1894 unlock: 1895 if (error != 0 || (flags & V_XSLEEP) != 0) 1896 MNT_REL(mp); 1897 MNT_IUNLOCK(mp); 1898 return (error); 1899 } 1900 1901 int 1902 vn_start_write(struct vnode *vp, struct mount **mpp, int flags) 1903 { 1904 struct mount *mp; 1905 int error; 1906 1907 KASSERT((flags & ~V_VALID_FLAGS) == 0, 1908 ("%s: invalid flags passed %d\n", __func__, flags)); 1909 1910 error = 0; 1911 /* 1912 * If a vnode is provided, get and return the mount point that 1913 * to which it will write. 1914 */ 1915 if (vp != NULL) { 1916 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1917 *mpp = NULL; 1918 if (error != EOPNOTSUPP) 1919 return (error); 1920 return (0); 1921 } 1922 } 1923 if ((mp = *mpp) == NULL) 1924 return (0); 1925 1926 /* 1927 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1928 * a vfs_ref(). 1929 * As long as a vnode is not provided we need to acquire a 1930 * refcount for the provided mountpoint too, in order to 1931 * emulate a vfs_ref(). 1932 */ 1933 if (vp == NULL) 1934 vfs_ref(mp); 1935 1936 error = vn_start_write_refed(mp, flags, false); 1937 if (error != 0 && (flags & V_NOWAIT) == 0) 1938 *mpp = NULL; 1939 return (error); 1940 } 1941 1942 /* 1943 * Secondary suspension. Used by operations such as vop_inactive 1944 * routines that are needed by the higher level functions. These 1945 * are allowed to proceed until all the higher level functions have 1946 * completed (indicated by mnt_writeopcount dropping to zero). At that 1947 * time, these operations are halted until the suspension is over. 1948 */ 1949 int 1950 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags) 1951 { 1952 struct mount *mp; 1953 int error, mflags; 1954 1955 KASSERT((flags & (~V_VALID_FLAGS | V_XSLEEP)) == 0, 1956 ("%s: invalid flags passed %d\n", __func__, flags)); 1957 1958 retry: 1959 if (vp != NULL) { 1960 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1961 *mpp = NULL; 1962 if (error != EOPNOTSUPP) 1963 return (error); 1964 return (0); 1965 } 1966 } 1967 /* 1968 * If we are not suspended or have not yet reached suspended 1969 * mode, then let the operation proceed. 1970 */ 1971 if ((mp = *mpp) == NULL) 1972 return (0); 1973 1974 /* 1975 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1976 * a vfs_ref(). 1977 * As long as a vnode is not provided we need to acquire a 1978 * refcount for the provided mountpoint too, in order to 1979 * emulate a vfs_ref(). 1980 */ 1981 MNT_ILOCK(mp); 1982 if (vp == NULL) 1983 MNT_REF(mp); 1984 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) { 1985 mp->mnt_secondary_writes++; 1986 mp->mnt_secondary_accwrites++; 1987 MNT_IUNLOCK(mp); 1988 return (0); 1989 } 1990 if ((flags & V_NOWAIT) != 0) { 1991 MNT_REL(mp); 1992 MNT_IUNLOCK(mp); 1993 *mpp = NULL; 1994 return (EWOULDBLOCK); 1995 } 1996 /* 1997 * Wait for the suspension to finish. 1998 */ 1999 mflags = 0; 2000 if ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0) { 2001 if ((flags & V_PCATCH) != 0) 2002 mflags |= PCATCH; 2003 } 2004 mflags |= (PUSER - 1) | PDROP; 2005 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, "suspfs", 0); 2006 vfs_rel(mp); 2007 if (error == 0) 2008 goto retry; 2009 *mpp = NULL; 2010 return (error); 2011 } 2012 2013 /* 2014 * Filesystem write operation has completed. If we are suspending and this 2015 * operation is the last one, notify the suspender that the suspension is 2016 * now in effect. 2017 */ 2018 void 2019 vn_finished_write(struct mount *mp) 2020 { 2021 struct mount_pcpu *mpcpu; 2022 int c; 2023 2024 if (mp == NULL) 2025 return; 2026 2027 if (vfs_op_thread_enter(mp, mpcpu)) { 2028 vfs_mp_count_sub_pcpu(mpcpu, writeopcount, 1); 2029 vfs_mp_count_sub_pcpu(mpcpu, ref, 1); 2030 vfs_op_thread_exit(mp, mpcpu); 2031 return; 2032 } 2033 2034 MNT_ILOCK(mp); 2035 vfs_assert_mount_counters(mp); 2036 MNT_REL(mp); 2037 c = --mp->mnt_writeopcount; 2038 if (mp->mnt_vfs_ops == 0) { 2039 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 2040 MNT_IUNLOCK(mp); 2041 return; 2042 } 2043 if (c < 0) 2044 vfs_dump_mount_counters(mp); 2045 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && c == 0) 2046 wakeup(&mp->mnt_writeopcount); 2047 MNT_IUNLOCK(mp); 2048 } 2049 2050 /* 2051 * Filesystem secondary write operation has completed. If we are 2052 * suspending and this operation is the last one, notify the suspender 2053 * that the suspension is now in effect. 2054 */ 2055 void 2056 vn_finished_secondary_write(struct mount *mp) 2057 { 2058 if (mp == NULL) 2059 return; 2060 MNT_ILOCK(mp); 2061 MNT_REL(mp); 2062 mp->mnt_secondary_writes--; 2063 if (mp->mnt_secondary_writes < 0) 2064 panic("vn_finished_secondary_write: neg cnt"); 2065 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 2066 mp->mnt_secondary_writes <= 0) 2067 wakeup(&mp->mnt_secondary_writes); 2068 MNT_IUNLOCK(mp); 2069 } 2070 2071 /* 2072 * Request a filesystem to suspend write operations. 2073 */ 2074 int 2075 vfs_write_suspend(struct mount *mp, int flags) 2076 { 2077 int error; 2078 2079 vfs_op_enter(mp); 2080 2081 MNT_ILOCK(mp); 2082 vfs_assert_mount_counters(mp); 2083 if (mp->mnt_susp_owner == curthread) { 2084 vfs_op_exit_locked(mp); 2085 MNT_IUNLOCK(mp); 2086 return (EALREADY); 2087 } 2088 while (mp->mnt_kern_flag & MNTK_SUSPEND) 2089 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0); 2090 2091 /* 2092 * Unmount holds a write reference on the mount point. If we 2093 * own busy reference and drain for writers, we deadlock with 2094 * the reference draining in the unmount path. Callers of 2095 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if 2096 * vfs_busy() reference is owned and caller is not in the 2097 * unmount context. 2098 */ 2099 if ((flags & VS_SKIP_UNMOUNT) != 0 && 2100 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) { 2101 vfs_op_exit_locked(mp); 2102 MNT_IUNLOCK(mp); 2103 return (EBUSY); 2104 } 2105 2106 mp->mnt_kern_flag |= MNTK_SUSPEND; 2107 mp->mnt_susp_owner = curthread; 2108 if (mp->mnt_writeopcount > 0) 2109 (void) msleep(&mp->mnt_writeopcount, 2110 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0); 2111 else 2112 MNT_IUNLOCK(mp); 2113 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0) { 2114 vfs_write_resume(mp, 0); 2115 /* vfs_write_resume does vfs_op_exit() for us */ 2116 } 2117 return (error); 2118 } 2119 2120 /* 2121 * Request a filesystem to resume write operations. 2122 */ 2123 void 2124 vfs_write_resume(struct mount *mp, int flags) 2125 { 2126 2127 MNT_ILOCK(mp); 2128 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 2129 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner")); 2130 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 | 2131 MNTK_SUSPENDED); 2132 mp->mnt_susp_owner = NULL; 2133 wakeup(&mp->mnt_writeopcount); 2134 wakeup(&mp->mnt_flag); 2135 curthread->td_pflags &= ~TDP_IGNSUSP; 2136 if ((flags & VR_START_WRITE) != 0) { 2137 MNT_REF(mp); 2138 mp->mnt_writeopcount++; 2139 } 2140 MNT_IUNLOCK(mp); 2141 if ((flags & VR_NO_SUSPCLR) == 0) 2142 VFS_SUSP_CLEAN(mp); 2143 vfs_op_exit(mp); 2144 } else if ((flags & VR_START_WRITE) != 0) { 2145 MNT_REF(mp); 2146 vn_start_write_refed(mp, 0, true); 2147 } else { 2148 MNT_IUNLOCK(mp); 2149 } 2150 } 2151 2152 /* 2153 * Helper loop around vfs_write_suspend() for filesystem unmount VFS 2154 * methods. 2155 */ 2156 int 2157 vfs_write_suspend_umnt(struct mount *mp) 2158 { 2159 int error; 2160 2161 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0, 2162 ("vfs_write_suspend_umnt: recursed")); 2163 2164 /* dounmount() already called vn_start_write(). */ 2165 for (;;) { 2166 vn_finished_write(mp); 2167 error = vfs_write_suspend(mp, 0); 2168 if (error != 0) { 2169 vn_start_write(NULL, &mp, V_WAIT); 2170 return (error); 2171 } 2172 MNT_ILOCK(mp); 2173 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0) 2174 break; 2175 MNT_IUNLOCK(mp); 2176 vn_start_write(NULL, &mp, V_WAIT); 2177 } 2178 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2); 2179 wakeup(&mp->mnt_flag); 2180 MNT_IUNLOCK(mp); 2181 curthread->td_pflags |= TDP_IGNSUSP; 2182 return (0); 2183 } 2184 2185 /* 2186 * Implement kqueues for files by translating it to vnode operation. 2187 */ 2188 static int 2189 vn_kqfilter(struct file *fp, struct knote *kn) 2190 { 2191 2192 return (VOP_KQFILTER(fp->f_vnode, kn)); 2193 } 2194 2195 int 2196 vn_kqfilter_opath(struct file *fp, struct knote *kn) 2197 { 2198 if ((fp->f_flag & FKQALLOWED) == 0) 2199 return (EBADF); 2200 return (vn_kqfilter(fp, kn)); 2201 } 2202 2203 /* 2204 * Simplified in-kernel wrapper calls for extended attribute access. 2205 * Both calls pass in a NULL credential, authorizing as "kernel" access. 2206 * Set IO_NODELOCKED in ioflg if the vnode is already locked. 2207 */ 2208 int 2209 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace, 2210 const char *attrname, int *buflen, char *buf, struct thread *td) 2211 { 2212 struct uio auio; 2213 struct iovec iov; 2214 int error; 2215 2216 iov.iov_len = *buflen; 2217 iov.iov_base = buf; 2218 2219 auio.uio_iov = &iov; 2220 auio.uio_iovcnt = 1; 2221 auio.uio_rw = UIO_READ; 2222 auio.uio_segflg = UIO_SYSSPACE; 2223 auio.uio_td = td; 2224 auio.uio_offset = 0; 2225 auio.uio_resid = *buflen; 2226 2227 if ((ioflg & IO_NODELOCKED) == 0) 2228 vn_lock(vp, LK_SHARED | LK_RETRY); 2229 2230 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2231 2232 /* authorize attribute retrieval as kernel */ 2233 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL, 2234 td); 2235 2236 if ((ioflg & IO_NODELOCKED) == 0) 2237 VOP_UNLOCK(vp); 2238 2239 if (error == 0) { 2240 *buflen = *buflen - auio.uio_resid; 2241 } 2242 2243 return (error); 2244 } 2245 2246 /* 2247 * XXX failure mode if partially written? 2248 */ 2249 int 2250 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace, 2251 const char *attrname, int buflen, char *buf, struct thread *td) 2252 { 2253 struct uio auio; 2254 struct iovec iov; 2255 struct mount *mp; 2256 int error; 2257 2258 iov.iov_len = buflen; 2259 iov.iov_base = buf; 2260 2261 auio.uio_iov = &iov; 2262 auio.uio_iovcnt = 1; 2263 auio.uio_rw = UIO_WRITE; 2264 auio.uio_segflg = UIO_SYSSPACE; 2265 auio.uio_td = td; 2266 auio.uio_offset = 0; 2267 auio.uio_resid = buflen; 2268 2269 if ((ioflg & IO_NODELOCKED) == 0) { 2270 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2271 return (error); 2272 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2273 } 2274 2275 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2276 2277 /* authorize attribute setting as kernel */ 2278 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td); 2279 2280 if ((ioflg & IO_NODELOCKED) == 0) { 2281 vn_finished_write(mp); 2282 VOP_UNLOCK(vp); 2283 } 2284 2285 return (error); 2286 } 2287 2288 int 2289 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace, 2290 const char *attrname, struct thread *td) 2291 { 2292 struct mount *mp; 2293 int error; 2294 2295 if ((ioflg & IO_NODELOCKED) == 0) { 2296 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2297 return (error); 2298 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2299 } 2300 2301 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2302 2303 /* authorize attribute removal as kernel */ 2304 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td); 2305 if (error == EOPNOTSUPP) 2306 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL, 2307 NULL, td); 2308 2309 if ((ioflg & IO_NODELOCKED) == 0) { 2310 vn_finished_write(mp); 2311 VOP_UNLOCK(vp); 2312 } 2313 2314 return (error); 2315 } 2316 2317 static int 2318 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags, 2319 struct vnode **rvp) 2320 { 2321 2322 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp)); 2323 } 2324 2325 int 2326 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp) 2327 { 2328 2329 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino, 2330 lkflags, rvp)); 2331 } 2332 2333 int 2334 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg, 2335 int lkflags, struct vnode **rvp) 2336 { 2337 struct mount *mp; 2338 int ltype, error; 2339 2340 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get"); 2341 mp = vp->v_mount; 2342 ltype = VOP_ISLOCKED(vp); 2343 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED, 2344 ("vn_vget_ino: vp not locked")); 2345 error = vfs_busy(mp, MBF_NOWAIT); 2346 if (error != 0) { 2347 vfs_ref(mp); 2348 VOP_UNLOCK(vp); 2349 error = vfs_busy(mp, 0); 2350 vn_lock(vp, ltype | LK_RETRY); 2351 vfs_rel(mp); 2352 if (error != 0) 2353 return (ENOENT); 2354 if (VN_IS_DOOMED(vp)) { 2355 vfs_unbusy(mp); 2356 return (ENOENT); 2357 } 2358 } 2359 VOP_UNLOCK(vp); 2360 error = alloc(mp, alloc_arg, lkflags, rvp); 2361 vfs_unbusy(mp); 2362 if (error != 0 || *rvp != vp) 2363 vn_lock(vp, ltype | LK_RETRY); 2364 if (VN_IS_DOOMED(vp)) { 2365 if (error == 0) { 2366 if (*rvp == vp) 2367 vunref(vp); 2368 else 2369 vput(*rvp); 2370 } 2371 error = ENOENT; 2372 } 2373 return (error); 2374 } 2375 2376 static void 2377 vn_send_sigxfsz(struct proc *p) 2378 { 2379 PROC_LOCK(p); 2380 kern_psignal(p, SIGXFSZ); 2381 PROC_UNLOCK(p); 2382 } 2383 2384 int 2385 vn_rlimit_trunc(u_quad_t size, struct thread *td) 2386 { 2387 if (size <= lim_cur(td, RLIMIT_FSIZE)) 2388 return (0); 2389 vn_send_sigxfsz(td->td_proc); 2390 return (EFBIG); 2391 } 2392 2393 static int 2394 vn_rlimit_fsizex1(const struct vnode *vp, struct uio *uio, off_t maxfsz, 2395 bool adj, struct thread *td) 2396 { 2397 off_t lim; 2398 bool ktr_write; 2399 2400 if (vp->v_type != VREG) 2401 return (0); 2402 2403 /* 2404 * Handle file system maximum file size. 2405 */ 2406 if (maxfsz != 0 && uio->uio_offset + uio->uio_resid > maxfsz) { 2407 if (!adj || uio->uio_offset >= maxfsz) 2408 return (EFBIG); 2409 uio->uio_resid = maxfsz - uio->uio_offset; 2410 } 2411 2412 /* 2413 * This is kernel write (e.g. vnode_pager) or accounting 2414 * write, ignore limit. 2415 */ 2416 if (td == NULL || (td->td_pflags2 & TDP2_ACCT) != 0) 2417 return (0); 2418 2419 /* 2420 * Calculate file size limit. 2421 */ 2422 ktr_write = (td->td_pflags & TDP_INKTRACE) != 0; 2423 lim = __predict_false(ktr_write) ? td->td_ktr_io_lim : 2424 lim_cur(td, RLIMIT_FSIZE); 2425 2426 /* 2427 * Is the limit reached? 2428 */ 2429 if (__predict_true((uoff_t)uio->uio_offset + uio->uio_resid <= lim)) 2430 return (0); 2431 2432 /* 2433 * Prepared filesystems can handle writes truncated to the 2434 * file size limit. 2435 */ 2436 if (adj && (uoff_t)uio->uio_offset < lim) { 2437 uio->uio_resid = lim - (uoff_t)uio->uio_offset; 2438 return (0); 2439 } 2440 2441 if (!ktr_write || ktr_filesize_limit_signal) 2442 vn_send_sigxfsz(td->td_proc); 2443 return (EFBIG); 2444 } 2445 2446 /* 2447 * Helper for VOP_WRITE() implementations, the common code to 2448 * handle maximum supported file size on the filesystem, and 2449 * RLIMIT_FSIZE, except for special writes from accounting subsystem 2450 * and ktrace. 2451 * 2452 * For maximum file size (maxfsz argument): 2453 * - return EFBIG if uio_offset is beyond it 2454 * - otherwise, clamp uio_resid if write would extend file beyond maxfsz. 2455 * 2456 * For RLIMIT_FSIZE: 2457 * - return EFBIG and send SIGXFSZ if uio_offset is beyond the limit 2458 * - otherwise, clamp uio_resid if write would extend file beyond limit. 2459 * 2460 * If clamping occured, the adjustment for uio_resid is stored in 2461 * *resid_adj, to be re-applied by vn_rlimit_fsizex_res() on return 2462 * from the VOP. 2463 */ 2464 int 2465 vn_rlimit_fsizex(const struct vnode *vp, struct uio *uio, off_t maxfsz, 2466 ssize_t *resid_adj, struct thread *td) 2467 { 2468 ssize_t resid_orig; 2469 int error; 2470 bool adj; 2471 2472 resid_orig = uio->uio_resid; 2473 adj = resid_adj != NULL; 2474 error = vn_rlimit_fsizex1(vp, uio, maxfsz, adj, td); 2475 if (adj) 2476 *resid_adj = resid_orig - uio->uio_resid; 2477 return (error); 2478 } 2479 2480 void 2481 vn_rlimit_fsizex_res(struct uio *uio, ssize_t resid_adj) 2482 { 2483 uio->uio_resid += resid_adj; 2484 } 2485 2486 int 2487 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio, 2488 struct thread *td) 2489 { 2490 return (vn_rlimit_fsizex(vp, __DECONST(struct uio *, uio), 0, NULL, 2491 td)); 2492 } 2493 2494 int 2495 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 2496 struct thread *td) 2497 { 2498 struct vnode *vp; 2499 2500 vp = fp->f_vnode; 2501 #ifdef AUDIT 2502 vn_lock(vp, LK_SHARED | LK_RETRY); 2503 AUDIT_ARG_VNODE1(vp); 2504 VOP_UNLOCK(vp); 2505 #endif 2506 return (setfmode(td, active_cred, vp, mode)); 2507 } 2508 2509 int 2510 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 2511 struct thread *td) 2512 { 2513 struct vnode *vp; 2514 2515 vp = fp->f_vnode; 2516 #ifdef AUDIT 2517 vn_lock(vp, LK_SHARED | LK_RETRY); 2518 AUDIT_ARG_VNODE1(vp); 2519 VOP_UNLOCK(vp); 2520 #endif 2521 return (setfown(td, active_cred, vp, uid, gid)); 2522 } 2523 2524 /* 2525 * Remove pages in the range ["start", "end") from the vnode's VM object. If 2526 * "end" is 0, then the range extends to the end of the object. 2527 */ 2528 void 2529 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 2530 { 2531 vm_object_t object; 2532 2533 if ((object = vp->v_object) == NULL) 2534 return; 2535 VM_OBJECT_WLOCK(object); 2536 vm_object_page_remove(object, start, end, 0); 2537 VM_OBJECT_WUNLOCK(object); 2538 } 2539 2540 /* 2541 * Like vn_pages_remove(), but skips invalid pages, which by definition are not 2542 * mapped into any process' address space. Filesystems may use this in 2543 * preference to vn_pages_remove() to avoid blocking on pages busied in 2544 * preparation for a VOP_GETPAGES. 2545 */ 2546 void 2547 vn_pages_remove_valid(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 2548 { 2549 vm_object_t object; 2550 2551 if ((object = vp->v_object) == NULL) 2552 return; 2553 VM_OBJECT_WLOCK(object); 2554 vm_object_page_remove(object, start, end, OBJPR_VALIDONLY); 2555 VM_OBJECT_WUNLOCK(object); 2556 } 2557 2558 int 2559 vn_bmap_seekhole_locked(struct vnode *vp, u_long cmd, off_t *off, 2560 struct ucred *cred) 2561 { 2562 vm_object_t obj; 2563 off_t size; 2564 daddr_t bn, bnp; 2565 uint64_t bsize; 2566 off_t noff; 2567 int error; 2568 2569 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2570 ("%s: Wrong command %lu", __func__, cmd)); 2571 ASSERT_VOP_ELOCKED(vp, "vn_bmap_seekhole_locked"); 2572 2573 if (vp->v_type != VREG) { 2574 error = ENOTTY; 2575 goto out; 2576 } 2577 error = vn_getsize_locked(vp, &size, cred); 2578 if (error != 0) 2579 goto out; 2580 noff = *off; 2581 if (noff < 0 || noff >= size) { 2582 error = ENXIO; 2583 goto out; 2584 } 2585 2586 /* See the comment in ufs_bmap_seekdata(). */ 2587 obj = vp->v_object; 2588 if (obj != NULL) { 2589 VM_OBJECT_WLOCK(obj); 2590 vm_object_page_clean(obj, 0, 0, OBJPC_SYNC); 2591 VM_OBJECT_WUNLOCK(obj); 2592 } 2593 2594 bsize = vp->v_mount->mnt_stat.f_iosize; 2595 for (bn = noff / bsize; noff < size; bn++, noff += bsize - 2596 noff % bsize) { 2597 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL); 2598 if (error == EOPNOTSUPP) { 2599 error = ENOTTY; 2600 goto out; 2601 } 2602 if ((bnp == -1 && cmd == FIOSEEKHOLE) || 2603 (bnp != -1 && cmd == FIOSEEKDATA)) { 2604 noff = bn * bsize; 2605 if (noff < *off) 2606 noff = *off; 2607 goto out; 2608 } 2609 } 2610 if (noff > size) 2611 noff = size; 2612 /* noff == size. There is an implicit hole at the end of file. */ 2613 if (cmd == FIOSEEKDATA) 2614 error = ENXIO; 2615 out: 2616 if (error == 0) 2617 *off = noff; 2618 return (error); 2619 } 2620 2621 int 2622 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred) 2623 { 2624 int error; 2625 2626 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2627 ("%s: Wrong command %lu", __func__, cmd)); 2628 2629 if (vn_lock(vp, LK_EXCLUSIVE) != 0) 2630 return (EBADF); 2631 error = vn_bmap_seekhole_locked(vp, cmd, off, cred); 2632 VOP_UNLOCK(vp); 2633 return (error); 2634 } 2635 2636 int 2637 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td) 2638 { 2639 struct ucred *cred; 2640 struct vnode *vp; 2641 off_t foffset, fsize, size; 2642 int error, noneg; 2643 2644 cred = td->td_ucred; 2645 vp = fp->f_vnode; 2646 foffset = foffset_lock(fp, 0); 2647 noneg = (vp->v_type != VCHR); 2648 error = 0; 2649 switch (whence) { 2650 case L_INCR: 2651 if (noneg && 2652 (foffset < 0 || 2653 (offset > 0 && foffset > OFF_MAX - offset))) { 2654 error = EOVERFLOW; 2655 break; 2656 } 2657 offset += foffset; 2658 break; 2659 case L_XTND: 2660 error = vn_getsize(vp, &fsize, cred); 2661 if (error != 0) 2662 break; 2663 2664 /* 2665 * If the file references a disk device, then fetch 2666 * the media size and use that to determine the ending 2667 * offset. 2668 */ 2669 if (fsize == 0 && vp->v_type == VCHR && 2670 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0) 2671 fsize = size; 2672 if (noneg && offset > 0 && fsize > OFF_MAX - offset) { 2673 error = EOVERFLOW; 2674 break; 2675 } 2676 offset += fsize; 2677 break; 2678 case L_SET: 2679 break; 2680 case SEEK_DATA: 2681 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td); 2682 if (error == ENOTTY) 2683 error = EINVAL; 2684 break; 2685 case SEEK_HOLE: 2686 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td); 2687 if (error == ENOTTY) 2688 error = EINVAL; 2689 break; 2690 default: 2691 error = EINVAL; 2692 } 2693 if (error == 0 && noneg && offset < 0) 2694 error = EINVAL; 2695 if (error != 0) 2696 goto drop; 2697 VFS_KNOTE_UNLOCKED(vp, 0); 2698 td->td_uretoff.tdu_off = offset; 2699 drop: 2700 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0); 2701 return (error); 2702 } 2703 2704 int 2705 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred, 2706 struct thread *td) 2707 { 2708 int error; 2709 2710 /* 2711 * Grant permission if the caller is the owner of the file, or 2712 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on 2713 * on the file. If the time pointer is null, then write 2714 * permission on the file is also sufficient. 2715 * 2716 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes: 2717 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES 2718 * will be allowed to set the times [..] to the current 2719 * server time. 2720 */ 2721 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td); 2722 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0) 2723 error = VOP_ACCESS(vp, VWRITE, cred, td); 2724 return (error); 2725 } 2726 2727 int 2728 vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2729 { 2730 struct vnode *vp; 2731 int error; 2732 2733 if (fp->f_type == DTYPE_FIFO) 2734 kif->kf_type = KF_TYPE_FIFO; 2735 else 2736 kif->kf_type = KF_TYPE_VNODE; 2737 vp = fp->f_vnode; 2738 vref(vp); 2739 FILEDESC_SUNLOCK(fdp); 2740 error = vn_fill_kinfo_vnode(vp, kif); 2741 vrele(vp); 2742 FILEDESC_SLOCK(fdp); 2743 return (error); 2744 } 2745 2746 static inline void 2747 vn_fill_junk(struct kinfo_file *kif) 2748 { 2749 size_t len, olen; 2750 2751 /* 2752 * Simulate vn_fullpath returning changing values for a given 2753 * vp during e.g. coredump. 2754 */ 2755 len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1; 2756 olen = strlen(kif->kf_path); 2757 if (len < olen) 2758 strcpy(&kif->kf_path[len - 1], "$"); 2759 else 2760 for (; olen < len; olen++) 2761 strcpy(&kif->kf_path[olen], "A"); 2762 } 2763 2764 int 2765 vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif) 2766 { 2767 struct vattr va; 2768 char *fullpath, *freepath; 2769 int error; 2770 2771 kif->kf_un.kf_file.kf_file_type = vntype_to_kinfo(vp->v_type); 2772 freepath = NULL; 2773 fullpath = "-"; 2774 error = vn_fullpath(vp, &fullpath, &freepath); 2775 if (error == 0) { 2776 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path)); 2777 } 2778 if (freepath != NULL) 2779 free(freepath, M_TEMP); 2780 2781 KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path, 2782 vn_fill_junk(kif); 2783 ); 2784 2785 /* 2786 * Retrieve vnode attributes. 2787 */ 2788 va.va_fsid = VNOVAL; 2789 va.va_rdev = NODEV; 2790 vn_lock(vp, LK_SHARED | LK_RETRY); 2791 error = VOP_GETATTR(vp, &va, curthread->td_ucred); 2792 VOP_UNLOCK(vp); 2793 if (error != 0) 2794 return (error); 2795 if (va.va_fsid != VNOVAL) 2796 kif->kf_un.kf_file.kf_file_fsid = va.va_fsid; 2797 else 2798 kif->kf_un.kf_file.kf_file_fsid = 2799 vp->v_mount->mnt_stat.f_fsid.val[0]; 2800 kif->kf_un.kf_file.kf_file_fsid_freebsd11 = 2801 kif->kf_un.kf_file.kf_file_fsid; /* truncate */ 2802 kif->kf_un.kf_file.kf_file_fileid = va.va_fileid; 2803 kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode); 2804 kif->kf_un.kf_file.kf_file_size = va.va_size; 2805 kif->kf_un.kf_file.kf_file_rdev = va.va_rdev; 2806 kif->kf_un.kf_file.kf_file_rdev_freebsd11 = 2807 kif->kf_un.kf_file.kf_file_rdev; /* truncate */ 2808 kif->kf_un.kf_file.kf_file_nlink = va.va_nlink; 2809 return (0); 2810 } 2811 2812 int 2813 vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size, 2814 vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff, 2815 struct thread *td) 2816 { 2817 #ifdef HWPMC_HOOKS 2818 struct pmckern_map_in pkm; 2819 #endif 2820 struct mount *mp; 2821 struct vnode *vp; 2822 vm_object_t object; 2823 vm_prot_t maxprot; 2824 boolean_t writecounted; 2825 int error; 2826 2827 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \ 2828 defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) 2829 /* 2830 * POSIX shared-memory objects are defined to have 2831 * kernel persistence, and are not defined to support 2832 * read(2)/write(2) -- or even open(2). Thus, we can 2833 * use MAP_ASYNC to trade on-disk coherence for speed. 2834 * The shm_open(3) library routine turns on the FPOSIXSHM 2835 * flag to request this behavior. 2836 */ 2837 if ((fp->f_flag & FPOSIXSHM) != 0) 2838 flags |= MAP_NOSYNC; 2839 #endif 2840 vp = fp->f_vnode; 2841 2842 /* 2843 * Ensure that file and memory protections are 2844 * compatible. Note that we only worry about 2845 * writability if mapping is shared; in this case, 2846 * current and max prot are dictated by the open file. 2847 * XXX use the vnode instead? Problem is: what 2848 * credentials do we use for determination? What if 2849 * proc does a setuid? 2850 */ 2851 mp = vp->v_mount; 2852 if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) { 2853 maxprot = VM_PROT_NONE; 2854 if ((prot & VM_PROT_EXECUTE) != 0) 2855 return (EACCES); 2856 } else 2857 maxprot = VM_PROT_EXECUTE; 2858 if ((fp->f_flag & FREAD) != 0) 2859 maxprot |= VM_PROT_READ; 2860 else if ((prot & VM_PROT_READ) != 0) 2861 return (EACCES); 2862 2863 /* 2864 * If we are sharing potential changes via MAP_SHARED and we 2865 * are trying to get write permission although we opened it 2866 * without asking for it, bail out. 2867 */ 2868 if ((flags & MAP_SHARED) != 0) { 2869 if ((fp->f_flag & FWRITE) != 0) 2870 maxprot |= VM_PROT_WRITE; 2871 else if ((prot & VM_PROT_WRITE) != 0) 2872 return (EACCES); 2873 } else { 2874 maxprot |= VM_PROT_WRITE; 2875 cap_maxprot |= VM_PROT_WRITE; 2876 } 2877 maxprot &= cap_maxprot; 2878 2879 /* 2880 * For regular files and shared memory, POSIX requires that 2881 * the value of foff be a legitimate offset within the data 2882 * object. In particular, negative offsets are invalid. 2883 * Blocking negative offsets and overflows here avoids 2884 * possible wraparound or user-level access into reserved 2885 * ranges of the data object later. In contrast, POSIX does 2886 * not dictate how offsets are used by device drivers, so in 2887 * the case of a device mapping a negative offset is passed 2888 * on. 2889 */ 2890 if ( 2891 #ifdef _LP64 2892 size > OFF_MAX || 2893 #endif 2894 foff > OFF_MAX - size) 2895 return (EINVAL); 2896 2897 writecounted = FALSE; 2898 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp, 2899 &foff, &object, &writecounted); 2900 if (error != 0) 2901 return (error); 2902 error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object, 2903 foff, writecounted, td); 2904 if (error != 0) { 2905 /* 2906 * If this mapping was accounted for in the vnode's 2907 * writecount, then undo that now. 2908 */ 2909 if (writecounted) 2910 vm_pager_release_writecount(object, 0, size); 2911 vm_object_deallocate(object); 2912 } 2913 #ifdef HWPMC_HOOKS 2914 /* Inform hwpmc(4) if an executable is being mapped. */ 2915 if (PMC_HOOK_INSTALLED(PMC_FN_MMAP)) { 2916 if ((prot & VM_PROT_EXECUTE) != 0 && error == 0) { 2917 pkm.pm_file = vp; 2918 pkm.pm_address = (uintptr_t) *addr; 2919 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_MMAP, (void *) &pkm); 2920 } 2921 } 2922 #endif 2923 return (error); 2924 } 2925 2926 void 2927 vn_fsid(struct vnode *vp, struct vattr *va) 2928 { 2929 fsid_t *f; 2930 2931 f = &vp->v_mount->mnt_stat.f_fsid; 2932 va->va_fsid = (uint32_t)f->val[1]; 2933 va->va_fsid <<= sizeof(f->val[1]) * NBBY; 2934 va->va_fsid += (uint32_t)f->val[0]; 2935 } 2936 2937 int 2938 vn_fsync_buf(struct vnode *vp, int waitfor) 2939 { 2940 struct buf *bp, *nbp; 2941 struct bufobj *bo; 2942 struct mount *mp; 2943 int error, maxretry; 2944 2945 error = 0; 2946 maxretry = 10000; /* large, arbitrarily chosen */ 2947 mp = NULL; 2948 if (vp->v_type == VCHR) { 2949 VI_LOCK(vp); 2950 mp = vp->v_rdev->si_mountpt; 2951 VI_UNLOCK(vp); 2952 } 2953 bo = &vp->v_bufobj; 2954 BO_LOCK(bo); 2955 loop1: 2956 /* 2957 * MARK/SCAN initialization to avoid infinite loops. 2958 */ 2959 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) { 2960 bp->b_vflags &= ~BV_SCANNED; 2961 bp->b_error = 0; 2962 } 2963 2964 /* 2965 * Flush all dirty buffers associated with a vnode. 2966 */ 2967 loop2: 2968 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) { 2969 if ((bp->b_vflags & BV_SCANNED) != 0) 2970 continue; 2971 bp->b_vflags |= BV_SCANNED; 2972 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL)) { 2973 if (waitfor != MNT_WAIT) 2974 continue; 2975 if (BUF_LOCK(bp, 2976 LK_EXCLUSIVE | LK_INTERLOCK | LK_SLEEPFAIL, 2977 BO_LOCKPTR(bo)) != 0) { 2978 BO_LOCK(bo); 2979 goto loop1; 2980 } 2981 BO_LOCK(bo); 2982 } 2983 BO_UNLOCK(bo); 2984 KASSERT(bp->b_bufobj == bo, 2985 ("bp %p wrong b_bufobj %p should be %p", 2986 bp, bp->b_bufobj, bo)); 2987 if ((bp->b_flags & B_DELWRI) == 0) 2988 panic("fsync: not dirty"); 2989 if ((vp->v_object != NULL) && (bp->b_flags & B_CLUSTEROK)) { 2990 vfs_bio_awrite(bp); 2991 } else { 2992 bremfree(bp); 2993 bawrite(bp); 2994 } 2995 if (maxretry < 1000) 2996 pause("dirty", hz < 1000 ? 1 : hz / 1000); 2997 BO_LOCK(bo); 2998 goto loop2; 2999 } 3000 3001 /* 3002 * If synchronous the caller expects us to completely resolve all 3003 * dirty buffers in the system. Wait for in-progress I/O to 3004 * complete (which could include background bitmap writes), then 3005 * retry if dirty blocks still exist. 3006 */ 3007 if (waitfor == MNT_WAIT) { 3008 bufobj_wwait(bo, 0, 0); 3009 if (bo->bo_dirty.bv_cnt > 0) { 3010 /* 3011 * If we are unable to write any of these buffers 3012 * then we fail now rather than trying endlessly 3013 * to write them out. 3014 */ 3015 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) 3016 if ((error = bp->b_error) != 0) 3017 break; 3018 if ((mp != NULL && mp->mnt_secondary_writes > 0) || 3019 (error == 0 && --maxretry >= 0)) 3020 goto loop1; 3021 if (error == 0) 3022 error = EAGAIN; 3023 } 3024 } 3025 BO_UNLOCK(bo); 3026 if (error != 0) 3027 vn_printf(vp, "fsync: giving up on dirty (error = %d) ", error); 3028 3029 return (error); 3030 } 3031 3032 /* 3033 * Copies a byte range from invp to outvp. Calls VOP_COPY_FILE_RANGE() 3034 * or vn_generic_copy_file_range() after rangelocking the byte ranges, 3035 * to do the actual copy. 3036 * vn_generic_copy_file_range() is factored out, so it can be called 3037 * from a VOP_COPY_FILE_RANGE() call as well, but handles vnodes from 3038 * different file systems. 3039 */ 3040 int 3041 vn_copy_file_range(struct vnode *invp, off_t *inoffp, struct vnode *outvp, 3042 off_t *outoffp, size_t *lenp, unsigned int flags, struct ucred *incred, 3043 struct ucred *outcred, struct thread *fsize_td) 3044 { 3045 int error; 3046 size_t len; 3047 uint64_t uval; 3048 3049 len = *lenp; 3050 *lenp = 0; /* For error returns. */ 3051 error = 0; 3052 3053 /* Do some sanity checks on the arguments. */ 3054 if (invp->v_type == VDIR || outvp->v_type == VDIR) 3055 error = EISDIR; 3056 else if (*inoffp < 0 || *outoffp < 0 || 3057 invp->v_type != VREG || outvp->v_type != VREG) 3058 error = EINVAL; 3059 if (error != 0) 3060 goto out; 3061 3062 /* Ensure offset + len does not wrap around. */ 3063 uval = *inoffp; 3064 uval += len; 3065 if (uval > INT64_MAX) 3066 len = INT64_MAX - *inoffp; 3067 uval = *outoffp; 3068 uval += len; 3069 if (uval > INT64_MAX) 3070 len = INT64_MAX - *outoffp; 3071 if (len == 0) 3072 goto out; 3073 3074 /* 3075 * If the two vnode are for the same file system, call 3076 * VOP_COPY_FILE_RANGE(), otherwise call vn_generic_copy_file_range() 3077 * which can handle copies across multiple file systems. 3078 */ 3079 *lenp = len; 3080 if (invp->v_mount == outvp->v_mount) 3081 error = VOP_COPY_FILE_RANGE(invp, inoffp, outvp, outoffp, 3082 lenp, flags, incred, outcred, fsize_td); 3083 else 3084 error = vn_generic_copy_file_range(invp, inoffp, outvp, 3085 outoffp, lenp, flags, incred, outcred, fsize_td); 3086 out: 3087 return (error); 3088 } 3089 3090 /* 3091 * Test len bytes of data starting at dat for all bytes == 0. 3092 * Return true if all bytes are zero, false otherwise. 3093 * Expects dat to be well aligned. 3094 */ 3095 static bool 3096 mem_iszero(void *dat, int len) 3097 { 3098 int i; 3099 const u_int *p; 3100 const char *cp; 3101 3102 for (p = dat; len > 0; len -= sizeof(*p), p++) { 3103 if (len >= sizeof(*p)) { 3104 if (*p != 0) 3105 return (false); 3106 } else { 3107 cp = (const char *)p; 3108 for (i = 0; i < len; i++, cp++) 3109 if (*cp != '\0') 3110 return (false); 3111 } 3112 } 3113 return (true); 3114 } 3115 3116 /* 3117 * Look for a hole in the output file and, if found, adjust *outoffp 3118 * and *xferp to skip past the hole. 3119 * *xferp is the entire hole length to be written and xfer2 is how many bytes 3120 * to be written as 0's upon return. 3121 */ 3122 static off_t 3123 vn_skip_hole(struct vnode *outvp, off_t xfer2, off_t *outoffp, off_t *xferp, 3124 off_t *dataoffp, off_t *holeoffp, struct ucred *cred) 3125 { 3126 int error; 3127 off_t delta; 3128 3129 if (*holeoffp == 0 || *holeoffp <= *outoffp) { 3130 *dataoffp = *outoffp; 3131 error = VOP_IOCTL(outvp, FIOSEEKDATA, dataoffp, 0, cred, 3132 curthread); 3133 if (error == 0) { 3134 *holeoffp = *dataoffp; 3135 error = VOP_IOCTL(outvp, FIOSEEKHOLE, holeoffp, 0, cred, 3136 curthread); 3137 } 3138 if (error != 0 || *holeoffp == *dataoffp) { 3139 /* 3140 * Since outvp is unlocked, it may be possible for 3141 * another thread to do a truncate(), lseek(), write() 3142 * creating a hole at startoff between the above 3143 * VOP_IOCTL() calls, if the other thread does not do 3144 * rangelocking. 3145 * If that happens, *holeoffp == *dataoffp and finding 3146 * the hole has failed, so disable vn_skip_hole(). 3147 */ 3148 *holeoffp = -1; /* Disable use of vn_skip_hole(). */ 3149 return (xfer2); 3150 } 3151 KASSERT(*dataoffp >= *outoffp, 3152 ("vn_skip_hole: dataoff=%jd < outoff=%jd", 3153 (intmax_t)*dataoffp, (intmax_t)*outoffp)); 3154 KASSERT(*holeoffp > *dataoffp, 3155 ("vn_skip_hole: holeoff=%jd <= dataoff=%jd", 3156 (intmax_t)*holeoffp, (intmax_t)*dataoffp)); 3157 } 3158 3159 /* 3160 * If there is a hole before the data starts, advance *outoffp and 3161 * *xferp past the hole. 3162 */ 3163 if (*dataoffp > *outoffp) { 3164 delta = *dataoffp - *outoffp; 3165 if (delta >= *xferp) { 3166 /* Entire *xferp is a hole. */ 3167 *outoffp += *xferp; 3168 *xferp = 0; 3169 return (0); 3170 } 3171 *xferp -= delta; 3172 *outoffp += delta; 3173 xfer2 = MIN(xfer2, *xferp); 3174 } 3175 3176 /* 3177 * If a hole starts before the end of this xfer2, reduce this xfer2 so 3178 * that the write ends at the start of the hole. 3179 * *holeoffp should always be greater than *outoffp, but for the 3180 * non-INVARIANTS case, check this to make sure xfer2 remains a sane 3181 * value. 3182 */ 3183 if (*holeoffp > *outoffp && *holeoffp < *outoffp + xfer2) 3184 xfer2 = *holeoffp - *outoffp; 3185 return (xfer2); 3186 } 3187 3188 /* 3189 * Write an xfer sized chunk to outvp in blksize blocks from dat. 3190 * dat is a maximum of blksize in length and can be written repeatedly in 3191 * the chunk. 3192 * If growfile == true, just grow the file via vn_truncate_locked() instead 3193 * of doing actual writes. 3194 * If checkhole == true, a hole is being punched, so skip over any hole 3195 * already in the output file. 3196 */ 3197 static int 3198 vn_write_outvp(struct vnode *outvp, char *dat, off_t outoff, off_t xfer, 3199 u_long blksize, bool growfile, bool checkhole, struct ucred *cred) 3200 { 3201 struct mount *mp; 3202 off_t dataoff, holeoff, xfer2; 3203 int error; 3204 3205 /* 3206 * Loop around doing writes of blksize until write has been completed. 3207 * Lock/unlock on each loop iteration so that a bwillwrite() can be 3208 * done for each iteration, since the xfer argument can be very 3209 * large if there is a large hole to punch in the output file. 3210 */ 3211 error = 0; 3212 holeoff = 0; 3213 do { 3214 xfer2 = MIN(xfer, blksize); 3215 if (checkhole) { 3216 /* 3217 * Punching a hole. Skip writing if there is 3218 * already a hole in the output file. 3219 */ 3220 xfer2 = vn_skip_hole(outvp, xfer2, &outoff, &xfer, 3221 &dataoff, &holeoff, cred); 3222 if (xfer == 0) 3223 break; 3224 if (holeoff < 0) 3225 checkhole = false; 3226 KASSERT(xfer2 > 0, ("vn_write_outvp: xfer2=%jd", 3227 (intmax_t)xfer2)); 3228 } 3229 bwillwrite(); 3230 mp = NULL; 3231 error = vn_start_write(outvp, &mp, V_WAIT); 3232 if (error != 0) 3233 break; 3234 if (growfile) { 3235 error = vn_lock(outvp, LK_EXCLUSIVE); 3236 if (error == 0) { 3237 error = vn_truncate_locked(outvp, outoff + xfer, 3238 false, cred); 3239 VOP_UNLOCK(outvp); 3240 } 3241 } else { 3242 error = vn_lock(outvp, vn_lktype_write(mp, outvp)); 3243 if (error == 0) { 3244 error = vn_rdwr(UIO_WRITE, outvp, dat, xfer2, 3245 outoff, UIO_SYSSPACE, IO_NODELOCKED, 3246 curthread->td_ucred, cred, NULL, curthread); 3247 outoff += xfer2; 3248 xfer -= xfer2; 3249 VOP_UNLOCK(outvp); 3250 } 3251 } 3252 if (mp != NULL) 3253 vn_finished_write(mp); 3254 } while (!growfile && xfer > 0 && error == 0); 3255 return (error); 3256 } 3257 3258 /* 3259 * Copy a byte range of one file to another. This function can handle the 3260 * case where invp and outvp are on different file systems. 3261 * It can also be called by a VOP_COPY_FILE_RANGE() to do the work, if there 3262 * is no better file system specific way to do it. 3263 */ 3264 int 3265 vn_generic_copy_file_range(struct vnode *invp, off_t *inoffp, 3266 struct vnode *outvp, off_t *outoffp, size_t *lenp, unsigned int flags, 3267 struct ucred *incred, struct ucred *outcred, struct thread *fsize_td) 3268 { 3269 struct mount *mp; 3270 off_t startoff, endoff, xfer, xfer2; 3271 u_long blksize; 3272 int error, interrupted; 3273 bool cantseek, readzeros, eof, lastblock, holetoeof; 3274 ssize_t aresid, r = 0; 3275 size_t copylen, len, savlen; 3276 off_t insize, outsize; 3277 char *dat; 3278 long holein, holeout; 3279 struct timespec curts, endts; 3280 3281 holein = holeout = 0; 3282 savlen = len = *lenp; 3283 error = 0; 3284 interrupted = 0; 3285 dat = NULL; 3286 3287 error = vn_lock(invp, LK_SHARED); 3288 if (error != 0) 3289 goto out; 3290 if (VOP_PATHCONF(invp, _PC_MIN_HOLE_SIZE, &holein) != 0) 3291 holein = 0; 3292 if (holein > 0) 3293 error = vn_getsize_locked(invp, &insize, incred); 3294 VOP_UNLOCK(invp); 3295 if (error != 0) 3296 goto out; 3297 3298 mp = NULL; 3299 error = vn_start_write(outvp, &mp, V_WAIT); 3300 if (error == 0) 3301 error = vn_lock(outvp, LK_EXCLUSIVE); 3302 if (error == 0) { 3303 /* 3304 * If fsize_td != NULL, do a vn_rlimit_fsizex() call, 3305 * now that outvp is locked. 3306 */ 3307 if (fsize_td != NULL) { 3308 struct uio io; 3309 3310 io.uio_offset = *outoffp; 3311 io.uio_resid = len; 3312 error = vn_rlimit_fsizex(outvp, &io, 0, &r, fsize_td); 3313 len = savlen = io.uio_resid; 3314 /* 3315 * No need to call vn_rlimit_fsizex_res before return, 3316 * since the uio is local. 3317 */ 3318 } 3319 if (VOP_PATHCONF(outvp, _PC_MIN_HOLE_SIZE, &holeout) != 0) 3320 holeout = 0; 3321 /* 3322 * Holes that are past EOF do not need to be written as a block 3323 * of zero bytes. So, truncate the output file as far as 3324 * possible and then use size to decide if writing 0 3325 * bytes is necessary in the loop below. 3326 */ 3327 if (error == 0) 3328 error = vn_getsize_locked(outvp, &outsize, outcred); 3329 if (error == 0 && outsize > *outoffp && outsize <= *outoffp + len) { 3330 #ifdef MAC 3331 error = mac_vnode_check_write(curthread->td_ucred, 3332 outcred, outvp); 3333 if (error == 0) 3334 #endif 3335 error = vn_truncate_locked(outvp, *outoffp, 3336 false, outcred); 3337 if (error == 0) 3338 outsize = *outoffp; 3339 } 3340 VOP_UNLOCK(outvp); 3341 } 3342 if (mp != NULL) 3343 vn_finished_write(mp); 3344 if (error != 0) 3345 goto out; 3346 3347 if (holein == 0 && holeout > 0) { 3348 /* 3349 * For this special case, the input data will be scanned 3350 * for blocks of all 0 bytes. For these blocks, the 3351 * write can be skipped for the output file to create 3352 * an unallocated region. 3353 * Therefore, use the appropriate size for the output file. 3354 */ 3355 blksize = holeout; 3356 if (blksize <= 512) { 3357 /* 3358 * Use f_iosize, since ZFS reports a _PC_MIN_HOLE_SIZE 3359 * of 512, although it actually only creates 3360 * unallocated regions for blocks >= f_iosize. 3361 */ 3362 blksize = outvp->v_mount->mnt_stat.f_iosize; 3363 } 3364 } else { 3365 /* 3366 * Use the larger of the two f_iosize values. If they are 3367 * not the same size, one will normally be an exact multiple of 3368 * the other, since they are both likely to be a power of 2. 3369 */ 3370 blksize = MAX(invp->v_mount->mnt_stat.f_iosize, 3371 outvp->v_mount->mnt_stat.f_iosize); 3372 } 3373 3374 /* Clip to sane limits. */ 3375 if (blksize < 4096) 3376 blksize = 4096; 3377 else if (blksize > maxphys) 3378 blksize = maxphys; 3379 dat = malloc(blksize, M_TEMP, M_WAITOK); 3380 3381 /* 3382 * If VOP_IOCTL(FIOSEEKHOLE) works for invp, use it and FIOSEEKDATA 3383 * to find holes. Otherwise, just scan the read block for all 0s 3384 * in the inner loop where the data copying is done. 3385 * Note that some file systems such as NFSv3, NFSv4.0 and NFSv4.1 may 3386 * support holes on the server, but do not support FIOSEEKHOLE. 3387 * The kernel flag COPY_FILE_RANGE_TIMEO1SEC is used to indicate 3388 * that this function should return after 1second with a partial 3389 * completion. 3390 */ 3391 if ((flags & COPY_FILE_RANGE_TIMEO1SEC) != 0) { 3392 getnanouptime(&endts); 3393 endts.tv_sec++; 3394 } else 3395 timespecclear(&endts); 3396 holetoeof = eof = false; 3397 while (len > 0 && error == 0 && !eof && interrupted == 0) { 3398 endoff = 0; /* To shut up compilers. */ 3399 cantseek = true; 3400 startoff = *inoffp; 3401 copylen = len; 3402 3403 /* 3404 * Find the next data area. If there is just a hole to EOF, 3405 * FIOSEEKDATA should fail with ENXIO. 3406 * (I do not know if any file system will report a hole to 3407 * EOF via FIOSEEKHOLE, but I am pretty sure FIOSEEKDATA 3408 * will fail for those file systems.) 3409 * 3410 * For input files that don't support FIOSEEKDATA/FIOSEEKHOLE, 3411 * the code just falls through to the inner copy loop. 3412 */ 3413 error = EINVAL; 3414 if (holein > 0) { 3415 error = VOP_IOCTL(invp, FIOSEEKDATA, &startoff, 0, 3416 incred, curthread); 3417 if (error == ENXIO) { 3418 startoff = endoff = insize; 3419 eof = holetoeof = true; 3420 error = 0; 3421 } 3422 } 3423 if (error == 0 && !holetoeof) { 3424 endoff = startoff; 3425 error = VOP_IOCTL(invp, FIOSEEKHOLE, &endoff, 0, 3426 incred, curthread); 3427 /* 3428 * Since invp is unlocked, it may be possible for 3429 * another thread to do a truncate(), lseek(), write() 3430 * creating a hole at startoff between the above 3431 * VOP_IOCTL() calls, if the other thread does not do 3432 * rangelocking. 3433 * If that happens, startoff == endoff and finding 3434 * the hole has failed, so set an error. 3435 */ 3436 if (error == 0 && startoff == endoff) 3437 error = EINVAL; /* Any error. Reset to 0. */ 3438 } 3439 if (error == 0) { 3440 if (startoff > *inoffp) { 3441 /* Found hole before data block. */ 3442 xfer = MIN(startoff - *inoffp, len); 3443 if (*outoffp < outsize) { 3444 /* Must write 0s to punch hole. */ 3445 xfer2 = MIN(outsize - *outoffp, 3446 xfer); 3447 memset(dat, 0, MIN(xfer2, blksize)); 3448 error = vn_write_outvp(outvp, dat, 3449 *outoffp, xfer2, blksize, false, 3450 holeout > 0, outcred); 3451 } 3452 3453 if (error == 0 && *outoffp + xfer > 3454 outsize && (xfer == len || holetoeof)) { 3455 /* Grow output file (hole at end). */ 3456 error = vn_write_outvp(outvp, dat, 3457 *outoffp, xfer, blksize, true, 3458 false, outcred); 3459 } 3460 if (error == 0) { 3461 *inoffp += xfer; 3462 *outoffp += xfer; 3463 len -= xfer; 3464 if (len < savlen) { 3465 interrupted = sig_intr(); 3466 if (timespecisset(&endts) && 3467 interrupted == 0) { 3468 getnanouptime(&curts); 3469 if (timespeccmp(&curts, 3470 &endts, >=)) 3471 interrupted = 3472 EINTR; 3473 } 3474 } 3475 } 3476 } 3477 copylen = MIN(len, endoff - startoff); 3478 cantseek = false; 3479 } else { 3480 cantseek = true; 3481 startoff = *inoffp; 3482 copylen = len; 3483 error = 0; 3484 } 3485 3486 xfer = blksize; 3487 if (cantseek) { 3488 /* 3489 * Set first xfer to end at a block boundary, so that 3490 * holes are more likely detected in the loop below via 3491 * the for all bytes 0 method. 3492 */ 3493 xfer -= (*inoffp % blksize); 3494 } 3495 /* Loop copying the data block. */ 3496 while (copylen > 0 && error == 0 && !eof && interrupted == 0) { 3497 if (copylen < xfer) 3498 xfer = copylen; 3499 error = vn_lock(invp, LK_SHARED); 3500 if (error != 0) 3501 goto out; 3502 error = vn_rdwr(UIO_READ, invp, dat, xfer, 3503 startoff, UIO_SYSSPACE, IO_NODELOCKED, 3504 curthread->td_ucred, incred, &aresid, 3505 curthread); 3506 VOP_UNLOCK(invp); 3507 lastblock = false; 3508 if (error == 0 && aresid > 0) { 3509 /* Stop the copy at EOF on the input file. */ 3510 xfer -= aresid; 3511 eof = true; 3512 lastblock = true; 3513 } 3514 if (error == 0) { 3515 /* 3516 * Skip the write for holes past the initial EOF 3517 * of the output file, unless this is the last 3518 * write of the output file at EOF. 3519 */ 3520 readzeros = cantseek ? mem_iszero(dat, xfer) : 3521 false; 3522 if (xfer == len) 3523 lastblock = true; 3524 if (!cantseek || *outoffp < outsize || 3525 lastblock || !readzeros) 3526 error = vn_write_outvp(outvp, dat, 3527 *outoffp, xfer, blksize, 3528 readzeros && lastblock && 3529 *outoffp >= outsize, false, 3530 outcred); 3531 if (error == 0) { 3532 *inoffp += xfer; 3533 startoff += xfer; 3534 *outoffp += xfer; 3535 copylen -= xfer; 3536 len -= xfer; 3537 if (len < savlen) { 3538 interrupted = sig_intr(); 3539 if (timespecisset(&endts) && 3540 interrupted == 0) { 3541 getnanouptime(&curts); 3542 if (timespeccmp(&curts, 3543 &endts, >=)) 3544 interrupted = 3545 EINTR; 3546 } 3547 } 3548 } 3549 } 3550 xfer = blksize; 3551 } 3552 } 3553 out: 3554 *lenp = savlen - len; 3555 free(dat, M_TEMP); 3556 return (error); 3557 } 3558 3559 static int 3560 vn_fallocate(struct file *fp, off_t offset, off_t len, struct thread *td) 3561 { 3562 struct mount *mp; 3563 struct vnode *vp; 3564 off_t olen, ooffset; 3565 int error; 3566 #ifdef AUDIT 3567 int audited_vnode1 = 0; 3568 #endif 3569 3570 vp = fp->f_vnode; 3571 if (vp->v_type != VREG) 3572 return (ENODEV); 3573 3574 /* Allocating blocks may take a long time, so iterate. */ 3575 for (;;) { 3576 olen = len; 3577 ooffset = offset; 3578 3579 bwillwrite(); 3580 mp = NULL; 3581 error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH); 3582 if (error != 0) 3583 break; 3584 error = vn_lock(vp, LK_EXCLUSIVE); 3585 if (error != 0) { 3586 vn_finished_write(mp); 3587 break; 3588 } 3589 #ifdef AUDIT 3590 if (!audited_vnode1) { 3591 AUDIT_ARG_VNODE1(vp); 3592 audited_vnode1 = 1; 3593 } 3594 #endif 3595 #ifdef MAC 3596 error = mac_vnode_check_write(td->td_ucred, fp->f_cred, vp); 3597 if (error == 0) 3598 #endif 3599 error = VOP_ALLOCATE(vp, &offset, &len, 0, 3600 td->td_ucred); 3601 VOP_UNLOCK(vp); 3602 vn_finished_write(mp); 3603 3604 if (olen + ooffset != offset + len) { 3605 panic("offset + len changed from %jx/%jx to %jx/%jx", 3606 ooffset, olen, offset, len); 3607 } 3608 if (error != 0 || len == 0) 3609 break; 3610 KASSERT(olen > len, ("Iteration did not make progress?")); 3611 maybe_yield(); 3612 } 3613 3614 return (error); 3615 } 3616 3617 static int 3618 vn_deallocate_impl(struct vnode *vp, off_t *offset, off_t *length, int flags, 3619 int ioflag, struct ucred *cred, struct ucred *active_cred, 3620 struct ucred *file_cred) 3621 { 3622 struct mount *mp; 3623 void *rl_cookie; 3624 off_t off, len; 3625 int error; 3626 #ifdef AUDIT 3627 bool audited_vnode1 = false; 3628 #endif 3629 3630 rl_cookie = NULL; 3631 error = 0; 3632 mp = NULL; 3633 off = *offset; 3634 len = *length; 3635 3636 if ((ioflag & (IO_NODELOCKED | IO_RANGELOCKED)) == 0) 3637 rl_cookie = vn_rangelock_wlock(vp, off, off + len); 3638 while (len > 0 && error == 0) { 3639 /* 3640 * Try to deallocate the longest range in one pass. 3641 * In case a pass takes too long to be executed, it returns 3642 * partial result. The residue will be proceeded in the next 3643 * pass. 3644 */ 3645 3646 if ((ioflag & IO_NODELOCKED) == 0) { 3647 bwillwrite(); 3648 if ((error = vn_start_write(vp, &mp, 3649 V_WAIT | V_PCATCH)) != 0) 3650 goto out; 3651 vn_lock(vp, vn_lktype_write(mp, vp) | LK_RETRY); 3652 } 3653 #ifdef AUDIT 3654 if (!audited_vnode1) { 3655 AUDIT_ARG_VNODE1(vp); 3656 audited_vnode1 = true; 3657 } 3658 #endif 3659 3660 #ifdef MAC 3661 if ((ioflag & IO_NOMACCHECK) == 0) 3662 error = mac_vnode_check_write(active_cred, file_cred, 3663 vp); 3664 #endif 3665 if (error == 0) 3666 error = VOP_DEALLOCATE(vp, &off, &len, flags, ioflag, 3667 cred); 3668 3669 if ((ioflag & IO_NODELOCKED) == 0) { 3670 VOP_UNLOCK(vp); 3671 if (mp != NULL) { 3672 vn_finished_write(mp); 3673 mp = NULL; 3674 } 3675 } 3676 if (error == 0 && len != 0) 3677 maybe_yield(); 3678 } 3679 out: 3680 if (rl_cookie != NULL) 3681 vn_rangelock_unlock(vp, rl_cookie); 3682 *offset = off; 3683 *length = len; 3684 return (error); 3685 } 3686 3687 /* 3688 * This function is supposed to be used in the situations where the deallocation 3689 * is not triggered by a user request. 3690 */ 3691 int 3692 vn_deallocate(struct vnode *vp, off_t *offset, off_t *length, int flags, 3693 int ioflag, struct ucred *active_cred, struct ucred *file_cred) 3694 { 3695 struct ucred *cred; 3696 3697 if (*offset < 0 || *length <= 0 || *length > OFF_MAX - *offset || 3698 flags != 0) 3699 return (EINVAL); 3700 if (vp->v_type != VREG) 3701 return (ENODEV); 3702 3703 cred = file_cred != NOCRED ? file_cred : active_cred; 3704 return (vn_deallocate_impl(vp, offset, length, flags, ioflag, cred, 3705 active_cred, file_cred)); 3706 } 3707 3708 static int 3709 vn_fspacectl(struct file *fp, int cmd, off_t *offset, off_t *length, int flags, 3710 struct ucred *active_cred, struct thread *td) 3711 { 3712 int error; 3713 struct vnode *vp; 3714 int ioflag; 3715 3716 KASSERT(cmd == SPACECTL_DEALLOC, ("vn_fspacectl: Invalid cmd")); 3717 KASSERT((flags & ~SPACECTL_F_SUPPORTED) == 0, 3718 ("vn_fspacectl: non-zero flags")); 3719 KASSERT(*offset >= 0 && *length > 0 && *length <= OFF_MAX - *offset, 3720 ("vn_fspacectl: offset/length overflow or underflow")); 3721 vp = fp->f_vnode; 3722 3723 if (vp->v_type != VREG) 3724 return (ENODEV); 3725 3726 ioflag = get_write_ioflag(fp); 3727 3728 switch (cmd) { 3729 case SPACECTL_DEALLOC: 3730 error = vn_deallocate_impl(vp, offset, length, flags, ioflag, 3731 active_cred, active_cred, fp->f_cred); 3732 break; 3733 default: 3734 panic("vn_fspacectl: unknown cmd %d", cmd); 3735 } 3736 3737 return (error); 3738 } 3739 3740 /* 3741 * Keep this assert as long as sizeof(struct dirent) is used as the maximum 3742 * entry size. 3743 */ 3744 _Static_assert(_GENERIC_MAXDIRSIZ == sizeof(struct dirent), 3745 "'struct dirent' size must be a multiple of its alignment " 3746 "(see _GENERIC_DIRLEN())"); 3747 3748 /* 3749 * Returns successive directory entries through some caller's provided buffer. 3750 * 3751 * This function automatically refills the provided buffer with calls to 3752 * VOP_READDIR() (after MAC permission checks). 3753 * 3754 * 'td' is used for credentials and passed to uiomove(). 'dirbuf' is the 3755 * caller's buffer to fill and 'dirbuflen' its allocated size. 'dirbuf' must 3756 * be properly aligned to access 'struct dirent' structures and 'dirbuflen' 3757 * must be greater than GENERIC_MAXDIRSIZ to avoid VOP_READDIR() returning 3758 * EINVAL (the latter is not a strong guarantee (yet); but EINVAL will always 3759 * be returned if this requirement is not verified). '*dpp' points to the 3760 * current directory entry in the buffer and '*len' contains the remaining 3761 * valid bytes in 'dirbuf' after 'dpp' (including the pointed entry). 3762 * 3763 * At first call (or when restarting the read), '*len' must have been set to 0, 3764 * '*off' to 0 (or any valid start offset) and '*eofflag' to 0. There are no 3765 * more entries as soon as '*len' is 0 after a call that returned 0. Calling 3766 * again this function after such a condition is considered an error and EINVAL 3767 * will be returned. Other possible error codes are those of VOP_READDIR(), 3768 * EINTEGRITY if the returned entries do not pass coherency tests, or EINVAL 3769 * (bad call). All errors are unrecoverable, i.e., the state ('*len', '*off' 3770 * and '*eofflag') must be re-initialized before a subsequent call. On error 3771 * or at end of directory, '*dpp' is reset to NULL. 3772 * 3773 * '*len', '*off' and '*eofflag' are internal state the caller should not 3774 * tamper with except as explained above. '*off' is the next directory offset 3775 * to read from to refill the buffer. '*eofflag' is set to 0 or 1 by the last 3776 * internal call to VOP_READDIR() that returned without error, indicating 3777 * whether it reached the end of the directory, and to 2 by this function after 3778 * all entries have been read. 3779 */ 3780 int 3781 vn_dir_next_dirent(struct vnode *vp, struct thread *td, 3782 char *dirbuf, size_t dirbuflen, 3783 struct dirent **dpp, size_t *len, off_t *off, int *eofflag) 3784 { 3785 struct dirent *dp = NULL; 3786 int reclen; 3787 int error; 3788 struct uio uio; 3789 struct iovec iov; 3790 3791 ASSERT_VOP_LOCKED(vp, "vnode not locked"); 3792 VNASSERT(vp->v_type == VDIR, vp, ("vnode is not a directory")); 3793 MPASS2((uintptr_t)dirbuf < (uintptr_t)dirbuf + dirbuflen, 3794 "Address space overflow"); 3795 3796 if (__predict_false(dirbuflen < GENERIC_MAXDIRSIZ)) { 3797 /* Don't take any chances in this case */ 3798 error = EINVAL; 3799 goto out; 3800 } 3801 3802 if (*len != 0) { 3803 dp = *dpp; 3804 3805 /* 3806 * The caller continued to call us after an error (we set dp to 3807 * NULL in a previous iteration). Bail out right now. 3808 */ 3809 if (__predict_false(dp == NULL)) 3810 return (EINVAL); 3811 3812 MPASS(*len <= dirbuflen); 3813 MPASS2((uintptr_t)dirbuf <= (uintptr_t)dp && 3814 (uintptr_t)dp + *len <= (uintptr_t)dirbuf + dirbuflen, 3815 "Filled range not inside buffer"); 3816 3817 reclen = dp->d_reclen; 3818 if (reclen >= *len) { 3819 /* End of buffer reached */ 3820 *len = 0; 3821 } else { 3822 dp = (struct dirent *)((char *)dp + reclen); 3823 *len -= reclen; 3824 } 3825 } 3826 3827 if (*len == 0) { 3828 dp = NULL; 3829 3830 /* Have to refill. */ 3831 switch (*eofflag) { 3832 case 0: 3833 break; 3834 3835 case 1: 3836 /* Nothing more to read. */ 3837 *eofflag = 2; /* Remember the caller reached EOF. */ 3838 goto success; 3839 3840 default: 3841 /* The caller didn't test for EOF. */ 3842 error = EINVAL; 3843 goto out; 3844 } 3845 3846 iov.iov_base = dirbuf; 3847 iov.iov_len = dirbuflen; 3848 3849 uio.uio_iov = &iov; 3850 uio.uio_iovcnt = 1; 3851 uio.uio_offset = *off; 3852 uio.uio_resid = dirbuflen; 3853 uio.uio_segflg = UIO_SYSSPACE; 3854 uio.uio_rw = UIO_READ; 3855 uio.uio_td = td; 3856 3857 #ifdef MAC 3858 error = mac_vnode_check_readdir(td->td_ucred, vp); 3859 if (error == 0) 3860 #endif 3861 error = VOP_READDIR(vp, &uio, td->td_ucred, eofflag, 3862 NULL, NULL); 3863 if (error != 0) 3864 goto out; 3865 3866 *len = dirbuflen - uio.uio_resid; 3867 *off = uio.uio_offset; 3868 3869 if (*len == 0) { 3870 /* Sanity check on INVARIANTS. */ 3871 MPASS(*eofflag != 0); 3872 *eofflag = 1; 3873 goto success; 3874 } 3875 3876 /* 3877 * Normalize the flag returned by VOP_READDIR(), since we use 2 3878 * as a sentinel value. 3879 */ 3880 if (*eofflag != 0) 3881 *eofflag = 1; 3882 3883 dp = (struct dirent *)dirbuf; 3884 } 3885 3886 if (__predict_false(*len < GENERIC_MINDIRSIZ || 3887 dp->d_reclen < GENERIC_MINDIRSIZ)) { 3888 error = EINTEGRITY; 3889 dp = NULL; 3890 goto out; 3891 } 3892 3893 success: 3894 error = 0; 3895 out: 3896 *dpp = dp; 3897 return (error); 3898 } 3899 3900 /* 3901 * Checks whether a directory is empty or not. 3902 * 3903 * If the directory is empty, returns 0, and if it is not, ENOTEMPTY. Other 3904 * values are genuine errors preventing the check. 3905 */ 3906 int 3907 vn_dir_check_empty(struct vnode *vp) 3908 { 3909 struct thread *const td = curthread; 3910 char *dirbuf; 3911 size_t dirbuflen, len; 3912 off_t off; 3913 int eofflag, error; 3914 struct dirent *dp; 3915 struct vattr va; 3916 3917 ASSERT_VOP_LOCKED(vp, "vfs_emptydir"); 3918 VNPASS(vp->v_type == VDIR, vp); 3919 3920 error = VOP_GETATTR(vp, &va, td->td_ucred); 3921 if (error != 0) 3922 return (error); 3923 3924 dirbuflen = max(DEV_BSIZE, GENERIC_MAXDIRSIZ); 3925 if (dirbuflen < va.va_blocksize) 3926 dirbuflen = va.va_blocksize; 3927 dirbuf = malloc(dirbuflen, M_TEMP, M_WAITOK); 3928 3929 len = 0; 3930 off = 0; 3931 eofflag = 0; 3932 3933 for (;;) { 3934 error = vn_dir_next_dirent(vp, td, dirbuf, dirbuflen, 3935 &dp, &len, &off, &eofflag); 3936 if (error != 0) 3937 goto end; 3938 3939 if (len == 0) { 3940 /* EOF */ 3941 error = 0; 3942 goto end; 3943 } 3944 3945 /* 3946 * Skip whiteouts. Unionfs operates on filesystems only and 3947 * not on hierarchies, so these whiteouts would be shadowed on 3948 * the system hierarchy but not for a union using the 3949 * filesystem of their directories as the upper layer. 3950 * Additionally, unionfs currently transparently exposes 3951 * union-specific metadata of its upper layer, meaning that 3952 * whiteouts can be seen through the union view in empty 3953 * directories. Taking into account these whiteouts would then 3954 * prevent mounting another filesystem on such effectively 3955 * empty directories. 3956 */ 3957 if (dp->d_type == DT_WHT) 3958 continue; 3959 3960 /* 3961 * Any file in the directory which is not '.' or '..' indicates 3962 * the directory is not empty. 3963 */ 3964 switch (dp->d_namlen) { 3965 case 2: 3966 if (dp->d_name[1] != '.') { 3967 /* Can't be '..' (nor '.') */ 3968 error = ENOTEMPTY; 3969 goto end; 3970 } 3971 /* FALLTHROUGH */ 3972 case 1: 3973 if (dp->d_name[0] != '.') { 3974 /* Can't be '..' nor '.' */ 3975 error = ENOTEMPTY; 3976 goto end; 3977 } 3978 break; 3979 3980 default: 3981 error = ENOTEMPTY; 3982 goto end; 3983 } 3984 } 3985 3986 end: 3987 free(dirbuf, M_TEMP); 3988 return (error); 3989 } 3990 3991 3992 static u_long vn_lock_pair_pause_cnt; 3993 SYSCTL_ULONG(_debug, OID_AUTO, vn_lock_pair_pause, CTLFLAG_RD, 3994 &vn_lock_pair_pause_cnt, 0, 3995 "Count of vn_lock_pair deadlocks"); 3996 3997 u_int vn_lock_pair_pause_max; 3998 SYSCTL_UINT(_debug, OID_AUTO, vn_lock_pair_pause_max, CTLFLAG_RW, 3999 &vn_lock_pair_pause_max, 0, 4000 "Max ticks for vn_lock_pair deadlock avoidance sleep"); 4001 4002 static void 4003 vn_lock_pair_pause(const char *wmesg) 4004 { 4005 atomic_add_long(&vn_lock_pair_pause_cnt, 1); 4006 pause(wmesg, prng32_bounded(vn_lock_pair_pause_max)); 4007 } 4008 4009 /* 4010 * Lock pair of vnodes vp1, vp2, avoiding lock order reversal. 4011 * vp1_locked indicates whether vp1 is locked; if not, vp1 must be 4012 * unlocked. Same for vp2 and vp2_locked. One of the vnodes can be 4013 * NULL. 4014 * 4015 * The function returns with both vnodes exclusively or shared locked, 4016 * according to corresponding lkflags, and guarantees that it does not 4017 * create lock order reversal with other threads during its execution. 4018 * Both vnodes could be unlocked temporary (and reclaimed). 4019 * 4020 * If requesting shared locking, locked vnode lock must not be recursed. 4021 */ 4022 void 4023 vn_lock_pair(struct vnode *vp1, bool vp1_locked, int lkflags1, 4024 struct vnode *vp2, bool vp2_locked, int lkflags2) 4025 { 4026 int error; 4027 4028 MPASS(lkflags1 == LK_SHARED || lkflags1 == LK_EXCLUSIVE); 4029 MPASS(lkflags2 == LK_SHARED || lkflags2 == LK_EXCLUSIVE); 4030 4031 if (vp1 == NULL && vp2 == NULL) 4032 return; 4033 4034 if (vp1 != NULL) { 4035 if (lkflags1 == LK_SHARED && 4036 (vp1->v_vnlock->lock_object.lo_flags & LK_NOSHARE) != 0) 4037 lkflags1 = LK_EXCLUSIVE; 4038 if (vp1_locked && VOP_ISLOCKED(vp1) != LK_EXCLUSIVE) { 4039 ASSERT_VOP_LOCKED(vp1, "vp1"); 4040 if (lkflags1 == LK_EXCLUSIVE) { 4041 VOP_UNLOCK(vp1); 4042 ASSERT_VOP_UNLOCKED(vp1, 4043 "vp1 shared recursed"); 4044 vp1_locked = false; 4045 } 4046 } else if (!vp1_locked) 4047 ASSERT_VOP_UNLOCKED(vp1, "vp1"); 4048 } else { 4049 vp1_locked = true; 4050 } 4051 4052 if (vp2 != NULL) { 4053 if (lkflags2 == LK_SHARED && 4054 (vp2->v_vnlock->lock_object.lo_flags & LK_NOSHARE) != 0) 4055 lkflags2 = LK_EXCLUSIVE; 4056 if (vp2_locked && VOP_ISLOCKED(vp2) != LK_EXCLUSIVE) { 4057 ASSERT_VOP_LOCKED(vp2, "vp2"); 4058 if (lkflags2 == LK_EXCLUSIVE) { 4059 VOP_UNLOCK(vp2); 4060 ASSERT_VOP_UNLOCKED(vp2, 4061 "vp2 shared recursed"); 4062 vp2_locked = false; 4063 } 4064 } else if (!vp2_locked) 4065 ASSERT_VOP_UNLOCKED(vp2, "vp2"); 4066 } else { 4067 vp2_locked = true; 4068 } 4069 4070 if (!vp1_locked && !vp2_locked) { 4071 vn_lock(vp1, lkflags1 | LK_RETRY); 4072 vp1_locked = true; 4073 } 4074 4075 while (!vp1_locked || !vp2_locked) { 4076 if (vp1_locked && vp2 != NULL) { 4077 if (vp1 != NULL) { 4078 error = VOP_LOCK1(vp2, lkflags2 | LK_NOWAIT, 4079 __FILE__, __LINE__); 4080 if (error == 0) 4081 break; 4082 VOP_UNLOCK(vp1); 4083 vp1_locked = false; 4084 vn_lock_pair_pause("vlp1"); 4085 } 4086 vn_lock(vp2, lkflags2 | LK_RETRY); 4087 vp2_locked = true; 4088 } 4089 if (vp2_locked && vp1 != NULL) { 4090 if (vp2 != NULL) { 4091 error = VOP_LOCK1(vp1, lkflags1 | LK_NOWAIT, 4092 __FILE__, __LINE__); 4093 if (error == 0) 4094 break; 4095 VOP_UNLOCK(vp2); 4096 vp2_locked = false; 4097 vn_lock_pair_pause("vlp2"); 4098 } 4099 vn_lock(vp1, lkflags1 | LK_RETRY); 4100 vp1_locked = true; 4101 } 4102 } 4103 if (vp1 != NULL) { 4104 if (lkflags1 == LK_EXCLUSIVE) 4105 ASSERT_VOP_ELOCKED(vp1, "vp1 ret"); 4106 else 4107 ASSERT_VOP_LOCKED(vp1, "vp1 ret"); 4108 } 4109 if (vp2 != NULL) { 4110 if (lkflags2 == LK_EXCLUSIVE) 4111 ASSERT_VOP_ELOCKED(vp2, "vp2 ret"); 4112 else 4113 ASSERT_VOP_LOCKED(vp2, "vp2 ret"); 4114 } 4115 } 4116 4117 int 4118 vn_lktype_write(struct mount *mp, struct vnode *vp) 4119 { 4120 if (MNT_SHARED_WRITES(mp) || 4121 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) 4122 return (LK_SHARED); 4123 return (LK_EXCLUSIVE); 4124 } 4125