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 bool do_io_fault, do_rangelock; 1447 1448 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write; 1449 vp = fp->f_vnode; 1450 1451 /* 1452 * The ability to read(2) on a directory has historically been 1453 * allowed for all users, but this can and has been the source of 1454 * at least one security issue in the past. As such, it is now hidden 1455 * away behind a sysctl for those that actually need it to use it, and 1456 * restricted to root when it's turned on to make it relatively safe to 1457 * leave on for longer sessions of need. 1458 */ 1459 if (vp->v_type == VDIR) { 1460 KASSERT(uio->uio_rw == UIO_READ, 1461 ("illegal write attempted on a directory")); 1462 if (!vfs_allow_read_dir) 1463 return (EISDIR); 1464 if ((error = priv_check(td, PRIV_VFS_READ_DIR)) != 0) 1465 return (EISDIR); 1466 } 1467 1468 do_io_fault = do_vn_io_fault(vp, uio); 1469 do_rangelock = do_io_fault || (vn_irflag_read(vp) & VIRF_PGREAD) != 0; 1470 foffset_lock_uio(fp, uio, flags); 1471 if (do_rangelock) { 1472 if (uio->uio_rw == UIO_READ) { 1473 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset, 1474 uio->uio_offset + uio->uio_resid); 1475 } else if ((fp->f_flag & O_APPEND) != 0 || 1476 (flags & FOF_OFFSET) == 0) { 1477 /* For appenders, punt and lock the whole range. */ 1478 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1479 } else { 1480 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset, 1481 uio->uio_offset + uio->uio_resid); 1482 } 1483 } 1484 if (do_io_fault) { 1485 args.kind = VN_IO_FAULT_FOP; 1486 args.args.fop_args.fp = fp; 1487 args.args.fop_args.doio = doio; 1488 args.cred = active_cred; 1489 args.flags = flags | FOF_OFFSET; 1490 error = vn_io_fault1(vp, uio, &args, td); 1491 } else { 1492 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td); 1493 } 1494 if (do_rangelock) 1495 vn_rangelock_unlock(vp, rl_cookie); 1496 foffset_unlock_uio(fp, uio, flags); 1497 return (error); 1498 } 1499 1500 /* 1501 * Helper function to perform the requested uiomove operation using 1502 * the held pages for io->uio_iov[0].iov_base buffer instead of 1503 * copyin/copyout. Access to the pages with uiomove_fromphys() 1504 * instead of iov_base prevents page faults that could occur due to 1505 * pmap_collect() invalidating the mapping created by 1506 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or 1507 * object cleanup revoking the write access from page mappings. 1508 * 1509 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove() 1510 * instead of plain uiomove(). 1511 */ 1512 int 1513 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio) 1514 { 1515 struct uio transp_uio; 1516 struct iovec transp_iov[1]; 1517 struct thread *td; 1518 size_t adv; 1519 int error, pgadv; 1520 1521 td = curthread; 1522 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1523 uio->uio_segflg != UIO_USERSPACE) 1524 return (uiomove(data, xfersize, uio)); 1525 1526 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1527 transp_iov[0].iov_base = data; 1528 transp_uio.uio_iov = &transp_iov[0]; 1529 transp_uio.uio_iovcnt = 1; 1530 if (xfersize > uio->uio_resid) 1531 xfersize = uio->uio_resid; 1532 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize; 1533 transp_uio.uio_offset = 0; 1534 transp_uio.uio_segflg = UIO_SYSSPACE; 1535 /* 1536 * Since transp_iov points to data, and td_ma page array 1537 * corresponds to original uio->uio_iov, we need to invert the 1538 * direction of the i/o operation as passed to 1539 * uiomove_fromphys(). 1540 */ 1541 switch (uio->uio_rw) { 1542 case UIO_WRITE: 1543 transp_uio.uio_rw = UIO_READ; 1544 break; 1545 case UIO_READ: 1546 transp_uio.uio_rw = UIO_WRITE; 1547 break; 1548 } 1549 transp_uio.uio_td = uio->uio_td; 1550 error = uiomove_fromphys(td->td_ma, 1551 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK, 1552 xfersize, &transp_uio); 1553 adv = xfersize - transp_uio.uio_resid; 1554 pgadv = 1555 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) - 1556 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT); 1557 td->td_ma += pgadv; 1558 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1559 pgadv)); 1560 td->td_ma_cnt -= pgadv; 1561 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv; 1562 uio->uio_iov->iov_len -= adv; 1563 uio->uio_resid -= adv; 1564 uio->uio_offset += adv; 1565 return (error); 1566 } 1567 1568 int 1569 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize, 1570 struct uio *uio) 1571 { 1572 struct thread *td; 1573 vm_offset_t iov_base; 1574 int cnt, pgadv; 1575 1576 td = curthread; 1577 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1578 uio->uio_segflg != UIO_USERSPACE) 1579 return (uiomove_fromphys(ma, offset, xfersize, uio)); 1580 1581 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1582 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize; 1583 iov_base = (vm_offset_t)uio->uio_iov->iov_base; 1584 switch (uio->uio_rw) { 1585 case UIO_WRITE: 1586 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma, 1587 offset, cnt); 1588 break; 1589 case UIO_READ: 1590 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK, 1591 cnt); 1592 break; 1593 } 1594 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT); 1595 td->td_ma += pgadv; 1596 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1597 pgadv)); 1598 td->td_ma_cnt -= pgadv; 1599 uio->uio_iov->iov_base = (char *)(iov_base + cnt); 1600 uio->uio_iov->iov_len -= cnt; 1601 uio->uio_resid -= cnt; 1602 uio->uio_offset += cnt; 1603 return (0); 1604 } 1605 1606 /* 1607 * File table truncate routine. 1608 */ 1609 static int 1610 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1611 struct thread *td) 1612 { 1613 struct mount *mp; 1614 struct vnode *vp; 1615 void *rl_cookie; 1616 int error; 1617 1618 vp = fp->f_vnode; 1619 1620 retry: 1621 /* 1622 * Lock the whole range for truncation. Otherwise split i/o 1623 * might happen partly before and partly after the truncation. 1624 */ 1625 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1626 error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH); 1627 if (error) 1628 goto out1; 1629 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1630 AUDIT_ARG_VNODE1(vp); 1631 if (vp->v_type == VDIR) { 1632 error = EISDIR; 1633 goto out; 1634 } 1635 #ifdef MAC 1636 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1637 if (error) 1638 goto out; 1639 #endif 1640 error = vn_truncate_locked(vp, length, (fp->f_flag & O_FSYNC) != 0, 1641 fp->f_cred); 1642 out: 1643 VOP_UNLOCK(vp); 1644 vn_finished_write(mp); 1645 out1: 1646 vn_rangelock_unlock(vp, rl_cookie); 1647 if (error == ERELOOKUP) 1648 goto retry; 1649 return (error); 1650 } 1651 1652 /* 1653 * Truncate a file that is already locked. 1654 */ 1655 int 1656 vn_truncate_locked(struct vnode *vp, off_t length, bool sync, 1657 struct ucred *cred) 1658 { 1659 struct vattr vattr; 1660 int error; 1661 1662 error = VOP_ADD_WRITECOUNT(vp, 1); 1663 if (error == 0) { 1664 VATTR_NULL(&vattr); 1665 vattr.va_size = length; 1666 if (sync) 1667 vattr.va_vaflags |= VA_SYNC; 1668 error = VOP_SETATTR(vp, &vattr, cred); 1669 VOP_ADD_WRITECOUNT_CHECKED(vp, -1); 1670 } 1671 return (error); 1672 } 1673 1674 /* 1675 * File table vnode stat routine. 1676 */ 1677 int 1678 vn_statfile(struct file *fp, struct stat *sb, struct ucred *active_cred) 1679 { 1680 struct vnode *vp = fp->f_vnode; 1681 int error; 1682 1683 vn_lock(vp, LK_SHARED | LK_RETRY); 1684 error = VOP_STAT(vp, sb, active_cred, fp->f_cred); 1685 VOP_UNLOCK(vp); 1686 1687 return (error); 1688 } 1689 1690 /* 1691 * File table vnode ioctl routine. 1692 */ 1693 static int 1694 vn_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, 1695 struct thread *td) 1696 { 1697 struct vnode *vp; 1698 struct fiobmap2_arg *bmarg; 1699 off_t size; 1700 int error; 1701 1702 vp = fp->f_vnode; 1703 switch (vp->v_type) { 1704 case VDIR: 1705 case VREG: 1706 switch (com) { 1707 case FIONREAD: 1708 error = vn_getsize(vp, &size, active_cred); 1709 if (error == 0) 1710 *(int *)data = size - fp->f_offset; 1711 return (error); 1712 case FIOBMAP2: 1713 bmarg = (struct fiobmap2_arg *)data; 1714 vn_lock(vp, LK_SHARED | LK_RETRY); 1715 #ifdef MAC 1716 error = mac_vnode_check_read(active_cred, fp->f_cred, 1717 vp); 1718 if (error == 0) 1719 #endif 1720 error = VOP_BMAP(vp, bmarg->bn, NULL, 1721 &bmarg->bn, &bmarg->runp, &bmarg->runb); 1722 VOP_UNLOCK(vp); 1723 return (error); 1724 case FIONBIO: 1725 case FIOASYNC: 1726 return (0); 1727 default: 1728 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1729 active_cred, td)); 1730 } 1731 break; 1732 case VCHR: 1733 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1734 active_cred, td)); 1735 default: 1736 return (ENOTTY); 1737 } 1738 } 1739 1740 /* 1741 * File table vnode poll routine. 1742 */ 1743 static int 1744 vn_poll(struct file *fp, int events, struct ucred *active_cred, 1745 struct thread *td) 1746 { 1747 struct vnode *vp; 1748 int error; 1749 1750 vp = fp->f_vnode; 1751 #if defined(MAC) || defined(AUDIT) 1752 if (AUDITING_TD(td) || mac_vnode_check_poll_enabled()) { 1753 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1754 AUDIT_ARG_VNODE1(vp); 1755 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp); 1756 VOP_UNLOCK(vp); 1757 if (error != 0) 1758 return (error); 1759 } 1760 #endif 1761 error = VOP_POLL(vp, events, fp->f_cred, td); 1762 return (error); 1763 } 1764 1765 /* 1766 * Acquire the requested lock and then check for validity. LK_RETRY 1767 * permits vn_lock to return doomed vnodes. 1768 */ 1769 static int __noinline 1770 _vn_lock_fallback(struct vnode *vp, int flags, const char *file, int line, 1771 int error) 1772 { 1773 1774 KASSERT((flags & LK_RETRY) == 0 || error == 0, 1775 ("vn_lock: error %d incompatible with flags %#x", error, flags)); 1776 1777 if (error == 0) 1778 VNASSERT(VN_IS_DOOMED(vp), vp, ("vnode not doomed")); 1779 1780 if ((flags & LK_RETRY) == 0) { 1781 if (error == 0) { 1782 VOP_UNLOCK(vp); 1783 error = ENOENT; 1784 } 1785 return (error); 1786 } 1787 1788 /* 1789 * LK_RETRY case. 1790 * 1791 * Nothing to do if we got the lock. 1792 */ 1793 if (error == 0) 1794 return (0); 1795 1796 /* 1797 * Interlock was dropped by the call in _vn_lock. 1798 */ 1799 flags &= ~LK_INTERLOCK; 1800 do { 1801 error = VOP_LOCK1(vp, flags, file, line); 1802 } while (error != 0); 1803 return (0); 1804 } 1805 1806 int 1807 _vn_lock(struct vnode *vp, int flags, const char *file, int line) 1808 { 1809 int error; 1810 1811 VNASSERT((flags & LK_TYPE_MASK) != 0, vp, 1812 ("vn_lock: no locktype (%d passed)", flags)); 1813 VNPASS(vp->v_holdcnt > 0, vp); 1814 error = VOP_LOCK1(vp, flags, file, line); 1815 if (__predict_false(error != 0 || VN_IS_DOOMED(vp))) 1816 return (_vn_lock_fallback(vp, flags, file, line, error)); 1817 return (0); 1818 } 1819 1820 /* 1821 * File table vnode close routine. 1822 */ 1823 static int 1824 vn_closefile(struct file *fp, struct thread *td) 1825 { 1826 struct vnode *vp; 1827 struct flock lf; 1828 int error; 1829 bool ref; 1830 1831 vp = fp->f_vnode; 1832 fp->f_ops = &badfileops; 1833 ref = (fp->f_flag & FHASLOCK) != 0; 1834 1835 error = vn_close1(vp, fp->f_flag, fp->f_cred, td, ref); 1836 1837 if (__predict_false(ref)) { 1838 lf.l_whence = SEEK_SET; 1839 lf.l_start = 0; 1840 lf.l_len = 0; 1841 lf.l_type = F_UNLCK; 1842 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK); 1843 vrele(vp); 1844 } 1845 return (error); 1846 } 1847 1848 /* 1849 * Preparing to start a filesystem write operation. If the operation is 1850 * permitted, then we bump the count of operations in progress and 1851 * proceed. If a suspend request is in progress, we wait until the 1852 * suspension is over, and then proceed. 1853 */ 1854 static int 1855 vn_start_write_refed(struct mount *mp, int flags, bool mplocked) 1856 { 1857 struct mount_pcpu *mpcpu; 1858 int error, mflags; 1859 1860 if (__predict_true(!mplocked) && (flags & V_XSLEEP) == 0 && 1861 vfs_op_thread_enter(mp, mpcpu)) { 1862 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 1863 vfs_mp_count_add_pcpu(mpcpu, writeopcount, 1); 1864 vfs_op_thread_exit(mp, mpcpu); 1865 return (0); 1866 } 1867 1868 if (mplocked) 1869 mtx_assert(MNT_MTX(mp), MA_OWNED); 1870 else 1871 MNT_ILOCK(mp); 1872 1873 error = 0; 1874 1875 /* 1876 * Check on status of suspension. 1877 */ 1878 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 || 1879 mp->mnt_susp_owner != curthread) { 1880 mflags = 0; 1881 if ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0) { 1882 if (flags & V_PCATCH) 1883 mflags |= PCATCH; 1884 } 1885 mflags |= (PUSER - 1); 1886 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1887 if ((flags & V_NOWAIT) != 0) { 1888 error = EWOULDBLOCK; 1889 goto unlock; 1890 } 1891 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, 1892 "suspfs", 0); 1893 if (error != 0) 1894 goto unlock; 1895 } 1896 } 1897 if ((flags & V_XSLEEP) != 0) 1898 goto unlock; 1899 mp->mnt_writeopcount++; 1900 unlock: 1901 if (error != 0 || (flags & V_XSLEEP) != 0) 1902 MNT_REL(mp); 1903 MNT_IUNLOCK(mp); 1904 return (error); 1905 } 1906 1907 int 1908 vn_start_write(struct vnode *vp, struct mount **mpp, int flags) 1909 { 1910 struct mount *mp; 1911 int error; 1912 1913 KASSERT((flags & ~V_VALID_FLAGS) == 0, 1914 ("%s: invalid flags passed %d\n", __func__, flags)); 1915 1916 error = 0; 1917 /* 1918 * If a vnode is provided, get and return the mount point that 1919 * to which it will write. 1920 */ 1921 if (vp != NULL) { 1922 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1923 *mpp = NULL; 1924 if (error != EOPNOTSUPP) 1925 return (error); 1926 return (0); 1927 } 1928 } 1929 if ((mp = *mpp) == NULL) 1930 return (0); 1931 1932 /* 1933 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1934 * a vfs_ref(). 1935 * As long as a vnode is not provided we need to acquire a 1936 * refcount for the provided mountpoint too, in order to 1937 * emulate a vfs_ref(). 1938 */ 1939 if (vp == NULL) 1940 vfs_ref(mp); 1941 1942 error = vn_start_write_refed(mp, flags, false); 1943 if (error != 0 && (flags & V_NOWAIT) == 0) 1944 *mpp = NULL; 1945 return (error); 1946 } 1947 1948 /* 1949 * Secondary suspension. Used by operations such as vop_inactive 1950 * routines that are needed by the higher level functions. These 1951 * are allowed to proceed until all the higher level functions have 1952 * completed (indicated by mnt_writeopcount dropping to zero). At that 1953 * time, these operations are halted until the suspension is over. 1954 */ 1955 int 1956 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags) 1957 { 1958 struct mount *mp; 1959 int error, mflags; 1960 1961 KASSERT((flags & (~V_VALID_FLAGS | V_XSLEEP)) == 0, 1962 ("%s: invalid flags passed %d\n", __func__, flags)); 1963 1964 retry: 1965 if (vp != NULL) { 1966 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1967 *mpp = NULL; 1968 if (error != EOPNOTSUPP) 1969 return (error); 1970 return (0); 1971 } 1972 } 1973 /* 1974 * If we are not suspended or have not yet reached suspended 1975 * mode, then let the operation proceed. 1976 */ 1977 if ((mp = *mpp) == NULL) 1978 return (0); 1979 1980 /* 1981 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1982 * a vfs_ref(). 1983 * As long as a vnode is not provided we need to acquire a 1984 * refcount for the provided mountpoint too, in order to 1985 * emulate a vfs_ref(). 1986 */ 1987 MNT_ILOCK(mp); 1988 if (vp == NULL) 1989 MNT_REF(mp); 1990 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) { 1991 mp->mnt_secondary_writes++; 1992 mp->mnt_secondary_accwrites++; 1993 MNT_IUNLOCK(mp); 1994 return (0); 1995 } 1996 if ((flags & V_NOWAIT) != 0) { 1997 MNT_REL(mp); 1998 MNT_IUNLOCK(mp); 1999 *mpp = NULL; 2000 return (EWOULDBLOCK); 2001 } 2002 /* 2003 * Wait for the suspension to finish. 2004 */ 2005 mflags = 0; 2006 if ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0) { 2007 if ((flags & V_PCATCH) != 0) 2008 mflags |= PCATCH; 2009 } 2010 mflags |= (PUSER - 1) | PDROP; 2011 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, "suspfs", 0); 2012 vfs_rel(mp); 2013 if (error == 0) 2014 goto retry; 2015 *mpp = NULL; 2016 return (error); 2017 } 2018 2019 /* 2020 * Filesystem write operation has completed. If we are suspending and this 2021 * operation is the last one, notify the suspender that the suspension is 2022 * now in effect. 2023 */ 2024 void 2025 vn_finished_write(struct mount *mp) 2026 { 2027 struct mount_pcpu *mpcpu; 2028 int c; 2029 2030 if (mp == NULL) 2031 return; 2032 2033 if (vfs_op_thread_enter(mp, mpcpu)) { 2034 vfs_mp_count_sub_pcpu(mpcpu, writeopcount, 1); 2035 vfs_mp_count_sub_pcpu(mpcpu, ref, 1); 2036 vfs_op_thread_exit(mp, mpcpu); 2037 return; 2038 } 2039 2040 MNT_ILOCK(mp); 2041 vfs_assert_mount_counters(mp); 2042 MNT_REL(mp); 2043 c = --mp->mnt_writeopcount; 2044 if (mp->mnt_vfs_ops == 0) { 2045 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 2046 MNT_IUNLOCK(mp); 2047 return; 2048 } 2049 if (c < 0) 2050 vfs_dump_mount_counters(mp); 2051 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && c == 0) 2052 wakeup(&mp->mnt_writeopcount); 2053 MNT_IUNLOCK(mp); 2054 } 2055 2056 /* 2057 * Filesystem secondary write operation has completed. If we are 2058 * suspending and this operation is the last one, notify the suspender 2059 * that the suspension is now in effect. 2060 */ 2061 void 2062 vn_finished_secondary_write(struct mount *mp) 2063 { 2064 if (mp == NULL) 2065 return; 2066 MNT_ILOCK(mp); 2067 MNT_REL(mp); 2068 mp->mnt_secondary_writes--; 2069 if (mp->mnt_secondary_writes < 0) 2070 panic("vn_finished_secondary_write: neg cnt"); 2071 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 2072 mp->mnt_secondary_writes <= 0) 2073 wakeup(&mp->mnt_secondary_writes); 2074 MNT_IUNLOCK(mp); 2075 } 2076 2077 /* 2078 * Request a filesystem to suspend write operations. 2079 */ 2080 int 2081 vfs_write_suspend(struct mount *mp, int flags) 2082 { 2083 int error; 2084 2085 vfs_op_enter(mp); 2086 2087 MNT_ILOCK(mp); 2088 vfs_assert_mount_counters(mp); 2089 if (mp->mnt_susp_owner == curthread) { 2090 vfs_op_exit_locked(mp); 2091 MNT_IUNLOCK(mp); 2092 return (EALREADY); 2093 } 2094 while (mp->mnt_kern_flag & MNTK_SUSPEND) 2095 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0); 2096 2097 /* 2098 * Unmount holds a write reference on the mount point. If we 2099 * own busy reference and drain for writers, we deadlock with 2100 * the reference draining in the unmount path. Callers of 2101 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if 2102 * vfs_busy() reference is owned and caller is not in the 2103 * unmount context. 2104 */ 2105 if ((flags & VS_SKIP_UNMOUNT) != 0 && 2106 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) { 2107 vfs_op_exit_locked(mp); 2108 MNT_IUNLOCK(mp); 2109 return (EBUSY); 2110 } 2111 2112 mp->mnt_kern_flag |= MNTK_SUSPEND; 2113 mp->mnt_susp_owner = curthread; 2114 if (mp->mnt_writeopcount > 0) 2115 (void) msleep(&mp->mnt_writeopcount, 2116 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0); 2117 else 2118 MNT_IUNLOCK(mp); 2119 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0) { 2120 vfs_write_resume(mp, 0); 2121 /* vfs_write_resume does vfs_op_exit() for us */ 2122 } 2123 return (error); 2124 } 2125 2126 /* 2127 * Request a filesystem to resume write operations. 2128 */ 2129 void 2130 vfs_write_resume(struct mount *mp, int flags) 2131 { 2132 2133 MNT_ILOCK(mp); 2134 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 2135 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner")); 2136 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 | 2137 MNTK_SUSPENDED); 2138 mp->mnt_susp_owner = NULL; 2139 wakeup(&mp->mnt_writeopcount); 2140 wakeup(&mp->mnt_flag); 2141 curthread->td_pflags &= ~TDP_IGNSUSP; 2142 if ((flags & VR_START_WRITE) != 0) { 2143 MNT_REF(mp); 2144 mp->mnt_writeopcount++; 2145 } 2146 MNT_IUNLOCK(mp); 2147 if ((flags & VR_NO_SUSPCLR) == 0) 2148 VFS_SUSP_CLEAN(mp); 2149 vfs_op_exit(mp); 2150 } else if ((flags & VR_START_WRITE) != 0) { 2151 MNT_REF(mp); 2152 vn_start_write_refed(mp, 0, true); 2153 } else { 2154 MNT_IUNLOCK(mp); 2155 } 2156 } 2157 2158 /* 2159 * Helper loop around vfs_write_suspend() for filesystem unmount VFS 2160 * methods. 2161 */ 2162 int 2163 vfs_write_suspend_umnt(struct mount *mp) 2164 { 2165 int error; 2166 2167 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0, 2168 ("vfs_write_suspend_umnt: recursed")); 2169 2170 /* dounmount() already called vn_start_write(). */ 2171 for (;;) { 2172 vn_finished_write(mp); 2173 error = vfs_write_suspend(mp, 0); 2174 if (error != 0) { 2175 vn_start_write(NULL, &mp, V_WAIT); 2176 return (error); 2177 } 2178 MNT_ILOCK(mp); 2179 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0) 2180 break; 2181 MNT_IUNLOCK(mp); 2182 vn_start_write(NULL, &mp, V_WAIT); 2183 } 2184 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2); 2185 wakeup(&mp->mnt_flag); 2186 MNT_IUNLOCK(mp); 2187 curthread->td_pflags |= TDP_IGNSUSP; 2188 return (0); 2189 } 2190 2191 /* 2192 * Implement kqueues for files by translating it to vnode operation. 2193 */ 2194 static int 2195 vn_kqfilter(struct file *fp, struct knote *kn) 2196 { 2197 2198 return (VOP_KQFILTER(fp->f_vnode, kn)); 2199 } 2200 2201 int 2202 vn_kqfilter_opath(struct file *fp, struct knote *kn) 2203 { 2204 if ((fp->f_flag & FKQALLOWED) == 0) 2205 return (EBADF); 2206 return (vn_kqfilter(fp, kn)); 2207 } 2208 2209 /* 2210 * Simplified in-kernel wrapper calls for extended attribute access. 2211 * Both calls pass in a NULL credential, authorizing as "kernel" access. 2212 * Set IO_NODELOCKED in ioflg if the vnode is already locked. 2213 */ 2214 int 2215 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace, 2216 const char *attrname, int *buflen, char *buf, struct thread *td) 2217 { 2218 struct uio auio; 2219 struct iovec iov; 2220 int error; 2221 2222 iov.iov_len = *buflen; 2223 iov.iov_base = buf; 2224 2225 auio.uio_iov = &iov; 2226 auio.uio_iovcnt = 1; 2227 auio.uio_rw = UIO_READ; 2228 auio.uio_segflg = UIO_SYSSPACE; 2229 auio.uio_td = td; 2230 auio.uio_offset = 0; 2231 auio.uio_resid = *buflen; 2232 2233 if ((ioflg & IO_NODELOCKED) == 0) 2234 vn_lock(vp, LK_SHARED | LK_RETRY); 2235 2236 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2237 2238 /* authorize attribute retrieval as kernel */ 2239 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL, 2240 td); 2241 2242 if ((ioflg & IO_NODELOCKED) == 0) 2243 VOP_UNLOCK(vp); 2244 2245 if (error == 0) { 2246 *buflen = *buflen - auio.uio_resid; 2247 } 2248 2249 return (error); 2250 } 2251 2252 /* 2253 * XXX failure mode if partially written? 2254 */ 2255 int 2256 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace, 2257 const char *attrname, int buflen, char *buf, struct thread *td) 2258 { 2259 struct uio auio; 2260 struct iovec iov; 2261 struct mount *mp; 2262 int error; 2263 2264 iov.iov_len = buflen; 2265 iov.iov_base = buf; 2266 2267 auio.uio_iov = &iov; 2268 auio.uio_iovcnt = 1; 2269 auio.uio_rw = UIO_WRITE; 2270 auio.uio_segflg = UIO_SYSSPACE; 2271 auio.uio_td = td; 2272 auio.uio_offset = 0; 2273 auio.uio_resid = buflen; 2274 2275 if ((ioflg & IO_NODELOCKED) == 0) { 2276 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2277 return (error); 2278 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2279 } 2280 2281 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2282 2283 /* authorize attribute setting as kernel */ 2284 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td); 2285 2286 if ((ioflg & IO_NODELOCKED) == 0) { 2287 vn_finished_write(mp); 2288 VOP_UNLOCK(vp); 2289 } 2290 2291 return (error); 2292 } 2293 2294 int 2295 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace, 2296 const char *attrname, struct thread *td) 2297 { 2298 struct mount *mp; 2299 int error; 2300 2301 if ((ioflg & IO_NODELOCKED) == 0) { 2302 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2303 return (error); 2304 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2305 } 2306 2307 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2308 2309 /* authorize attribute removal as kernel */ 2310 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td); 2311 if (error == EOPNOTSUPP) 2312 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL, 2313 NULL, td); 2314 2315 if ((ioflg & IO_NODELOCKED) == 0) { 2316 vn_finished_write(mp); 2317 VOP_UNLOCK(vp); 2318 } 2319 2320 return (error); 2321 } 2322 2323 static int 2324 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags, 2325 struct vnode **rvp) 2326 { 2327 2328 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp)); 2329 } 2330 2331 int 2332 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp) 2333 { 2334 2335 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino, 2336 lkflags, rvp)); 2337 } 2338 2339 int 2340 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg, 2341 int lkflags, struct vnode **rvp) 2342 { 2343 struct mount *mp; 2344 int ltype, error; 2345 2346 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get"); 2347 mp = vp->v_mount; 2348 ltype = VOP_ISLOCKED(vp); 2349 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED, 2350 ("vn_vget_ino: vp not locked")); 2351 error = vfs_busy(mp, MBF_NOWAIT); 2352 if (error != 0) { 2353 vfs_ref(mp); 2354 VOP_UNLOCK(vp); 2355 error = vfs_busy(mp, 0); 2356 vn_lock(vp, ltype | LK_RETRY); 2357 vfs_rel(mp); 2358 if (error != 0) 2359 return (ENOENT); 2360 if (VN_IS_DOOMED(vp)) { 2361 vfs_unbusy(mp); 2362 return (ENOENT); 2363 } 2364 } 2365 VOP_UNLOCK(vp); 2366 error = alloc(mp, alloc_arg, lkflags, rvp); 2367 vfs_unbusy(mp); 2368 if (error != 0 || *rvp != vp) 2369 vn_lock(vp, ltype | LK_RETRY); 2370 if (VN_IS_DOOMED(vp)) { 2371 if (error == 0) { 2372 if (*rvp == vp) 2373 vunref(vp); 2374 else 2375 vput(*rvp); 2376 } 2377 error = ENOENT; 2378 } 2379 return (error); 2380 } 2381 2382 static void 2383 vn_send_sigxfsz(struct proc *p) 2384 { 2385 PROC_LOCK(p); 2386 kern_psignal(p, SIGXFSZ); 2387 PROC_UNLOCK(p); 2388 } 2389 2390 int 2391 vn_rlimit_trunc(u_quad_t size, struct thread *td) 2392 { 2393 if (size <= lim_cur(td, RLIMIT_FSIZE)) 2394 return (0); 2395 vn_send_sigxfsz(td->td_proc); 2396 return (EFBIG); 2397 } 2398 2399 static int 2400 vn_rlimit_fsizex1(const struct vnode *vp, struct uio *uio, off_t maxfsz, 2401 bool adj, struct thread *td) 2402 { 2403 off_t lim; 2404 bool ktr_write; 2405 2406 if (vp->v_type != VREG) 2407 return (0); 2408 2409 /* 2410 * Handle file system maximum file size. 2411 */ 2412 if (maxfsz != 0 && uio->uio_offset + uio->uio_resid > maxfsz) { 2413 if (!adj || uio->uio_offset >= maxfsz) 2414 return (EFBIG); 2415 uio->uio_resid = maxfsz - uio->uio_offset; 2416 } 2417 2418 /* 2419 * This is kernel write (e.g. vnode_pager) or accounting 2420 * write, ignore limit. 2421 */ 2422 if (td == NULL || (td->td_pflags2 & TDP2_ACCT) != 0) 2423 return (0); 2424 2425 /* 2426 * Calculate file size limit. 2427 */ 2428 ktr_write = (td->td_pflags & TDP_INKTRACE) != 0; 2429 lim = __predict_false(ktr_write) ? td->td_ktr_io_lim : 2430 lim_cur(td, RLIMIT_FSIZE); 2431 2432 /* 2433 * Is the limit reached? 2434 */ 2435 if (__predict_true((uoff_t)uio->uio_offset + uio->uio_resid <= lim)) 2436 return (0); 2437 2438 /* 2439 * Prepared filesystems can handle writes truncated to the 2440 * file size limit. 2441 */ 2442 if (adj && (uoff_t)uio->uio_offset < lim) { 2443 uio->uio_resid = lim - (uoff_t)uio->uio_offset; 2444 return (0); 2445 } 2446 2447 if (!ktr_write || ktr_filesize_limit_signal) 2448 vn_send_sigxfsz(td->td_proc); 2449 return (EFBIG); 2450 } 2451 2452 /* 2453 * Helper for VOP_WRITE() implementations, the common code to 2454 * handle maximum supported file size on the filesystem, and 2455 * RLIMIT_FSIZE, except for special writes from accounting subsystem 2456 * and ktrace. 2457 * 2458 * For maximum file size (maxfsz argument): 2459 * - return EFBIG if uio_offset is beyond it 2460 * - otherwise, clamp uio_resid if write would extend file beyond maxfsz. 2461 * 2462 * For RLIMIT_FSIZE: 2463 * - return EFBIG and send SIGXFSZ if uio_offset is beyond the limit 2464 * - otherwise, clamp uio_resid if write would extend file beyond limit. 2465 * 2466 * If clamping occured, the adjustment for uio_resid is stored in 2467 * *resid_adj, to be re-applied by vn_rlimit_fsizex_res() on return 2468 * from the VOP. 2469 */ 2470 int 2471 vn_rlimit_fsizex(const struct vnode *vp, struct uio *uio, off_t maxfsz, 2472 ssize_t *resid_adj, struct thread *td) 2473 { 2474 ssize_t resid_orig; 2475 int error; 2476 bool adj; 2477 2478 resid_orig = uio->uio_resid; 2479 adj = resid_adj != NULL; 2480 error = vn_rlimit_fsizex1(vp, uio, maxfsz, adj, td); 2481 if (adj) 2482 *resid_adj = resid_orig - uio->uio_resid; 2483 return (error); 2484 } 2485 2486 void 2487 vn_rlimit_fsizex_res(struct uio *uio, ssize_t resid_adj) 2488 { 2489 uio->uio_resid += resid_adj; 2490 } 2491 2492 int 2493 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio, 2494 struct thread *td) 2495 { 2496 return (vn_rlimit_fsizex(vp, __DECONST(struct uio *, uio), 0, NULL, 2497 td)); 2498 } 2499 2500 int 2501 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 2502 struct thread *td) 2503 { 2504 struct vnode *vp; 2505 2506 vp = fp->f_vnode; 2507 #ifdef AUDIT 2508 vn_lock(vp, LK_SHARED | LK_RETRY); 2509 AUDIT_ARG_VNODE1(vp); 2510 VOP_UNLOCK(vp); 2511 #endif 2512 return (setfmode(td, active_cred, vp, mode)); 2513 } 2514 2515 int 2516 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 2517 struct thread *td) 2518 { 2519 struct vnode *vp; 2520 2521 vp = fp->f_vnode; 2522 #ifdef AUDIT 2523 vn_lock(vp, LK_SHARED | LK_RETRY); 2524 AUDIT_ARG_VNODE1(vp); 2525 VOP_UNLOCK(vp); 2526 #endif 2527 return (setfown(td, active_cred, vp, uid, gid)); 2528 } 2529 2530 /* 2531 * Remove pages in the range ["start", "end") from the vnode's VM object. If 2532 * "end" is 0, then the range extends to the end of the object. 2533 */ 2534 void 2535 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 2536 { 2537 vm_object_t object; 2538 2539 if ((object = vp->v_object) == NULL) 2540 return; 2541 VM_OBJECT_WLOCK(object); 2542 vm_object_page_remove(object, start, end, 0); 2543 VM_OBJECT_WUNLOCK(object); 2544 } 2545 2546 /* 2547 * Like vn_pages_remove(), but skips invalid pages, which by definition are not 2548 * mapped into any process' address space. Filesystems may use this in 2549 * preference to vn_pages_remove() to avoid blocking on pages busied in 2550 * preparation for a VOP_GETPAGES. 2551 */ 2552 void 2553 vn_pages_remove_valid(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 2554 { 2555 vm_object_t object; 2556 2557 if ((object = vp->v_object) == NULL) 2558 return; 2559 VM_OBJECT_WLOCK(object); 2560 vm_object_page_remove(object, start, end, OBJPR_VALIDONLY); 2561 VM_OBJECT_WUNLOCK(object); 2562 } 2563 2564 int 2565 vn_bmap_seekhole_locked(struct vnode *vp, u_long cmd, off_t *off, 2566 struct ucred *cred) 2567 { 2568 vm_object_t obj; 2569 off_t size; 2570 daddr_t bn, bnp; 2571 uint64_t bsize; 2572 off_t noff; 2573 int error; 2574 2575 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2576 ("%s: Wrong command %lu", __func__, cmd)); 2577 ASSERT_VOP_ELOCKED(vp, "vn_bmap_seekhole_locked"); 2578 2579 if (vp->v_type != VREG) { 2580 error = ENOTTY; 2581 goto out; 2582 } 2583 error = vn_getsize_locked(vp, &size, cred); 2584 if (error != 0) 2585 goto out; 2586 noff = *off; 2587 if (noff < 0 || noff >= size) { 2588 error = ENXIO; 2589 goto out; 2590 } 2591 2592 /* See the comment in ufs_bmap_seekdata(). */ 2593 obj = vp->v_object; 2594 if (obj != NULL) { 2595 VM_OBJECT_WLOCK(obj); 2596 vm_object_page_clean(obj, 0, 0, OBJPC_SYNC); 2597 VM_OBJECT_WUNLOCK(obj); 2598 } 2599 2600 bsize = vp->v_mount->mnt_stat.f_iosize; 2601 for (bn = noff / bsize; noff < size; bn++, noff += bsize - 2602 noff % bsize) { 2603 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL); 2604 if (error == EOPNOTSUPP) { 2605 error = ENOTTY; 2606 goto out; 2607 } 2608 if ((bnp == -1 && cmd == FIOSEEKHOLE) || 2609 (bnp != -1 && cmd == FIOSEEKDATA)) { 2610 noff = bn * bsize; 2611 if (noff < *off) 2612 noff = *off; 2613 goto out; 2614 } 2615 } 2616 if (noff > size) 2617 noff = size; 2618 /* noff == size. There is an implicit hole at the end of file. */ 2619 if (cmd == FIOSEEKDATA) 2620 error = ENXIO; 2621 out: 2622 if (error == 0) 2623 *off = noff; 2624 return (error); 2625 } 2626 2627 int 2628 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred) 2629 { 2630 int error; 2631 2632 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2633 ("%s: Wrong command %lu", __func__, cmd)); 2634 2635 if (vn_lock(vp, LK_EXCLUSIVE) != 0) 2636 return (EBADF); 2637 error = vn_bmap_seekhole_locked(vp, cmd, off, cred); 2638 VOP_UNLOCK(vp); 2639 return (error); 2640 } 2641 2642 int 2643 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td) 2644 { 2645 struct ucred *cred; 2646 struct vnode *vp; 2647 off_t foffset, fsize, size; 2648 int error, noneg; 2649 2650 cred = td->td_ucred; 2651 vp = fp->f_vnode; 2652 foffset = foffset_lock(fp, 0); 2653 noneg = (vp->v_type != VCHR); 2654 error = 0; 2655 switch (whence) { 2656 case L_INCR: 2657 if (noneg && 2658 (foffset < 0 || 2659 (offset > 0 && foffset > OFF_MAX - offset))) { 2660 error = EOVERFLOW; 2661 break; 2662 } 2663 offset += foffset; 2664 break; 2665 case L_XTND: 2666 error = vn_getsize(vp, &fsize, cred); 2667 if (error != 0) 2668 break; 2669 2670 /* 2671 * If the file references a disk device, then fetch 2672 * the media size and use that to determine the ending 2673 * offset. 2674 */ 2675 if (fsize == 0 && vp->v_type == VCHR && 2676 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0) 2677 fsize = size; 2678 if (noneg && offset > 0 && fsize > OFF_MAX - offset) { 2679 error = EOVERFLOW; 2680 break; 2681 } 2682 offset += fsize; 2683 break; 2684 case L_SET: 2685 break; 2686 case SEEK_DATA: 2687 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td); 2688 if (error == ENOTTY) 2689 error = EINVAL; 2690 break; 2691 case SEEK_HOLE: 2692 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td); 2693 if (error == ENOTTY) 2694 error = EINVAL; 2695 break; 2696 default: 2697 error = EINVAL; 2698 } 2699 if (error == 0 && noneg && offset < 0) 2700 error = EINVAL; 2701 if (error != 0) 2702 goto drop; 2703 VFS_KNOTE_UNLOCKED(vp, 0); 2704 td->td_uretoff.tdu_off = offset; 2705 drop: 2706 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0); 2707 return (error); 2708 } 2709 2710 int 2711 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred, 2712 struct thread *td) 2713 { 2714 int error; 2715 2716 /* 2717 * Grant permission if the caller is the owner of the file, or 2718 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on 2719 * on the file. If the time pointer is null, then write 2720 * permission on the file is also sufficient. 2721 * 2722 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes: 2723 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES 2724 * will be allowed to set the times [..] to the current 2725 * server time. 2726 */ 2727 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td); 2728 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0) 2729 error = VOP_ACCESS(vp, VWRITE, cred, td); 2730 return (error); 2731 } 2732 2733 int 2734 vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2735 { 2736 struct vnode *vp; 2737 int error; 2738 2739 if (fp->f_type == DTYPE_FIFO) 2740 kif->kf_type = KF_TYPE_FIFO; 2741 else 2742 kif->kf_type = KF_TYPE_VNODE; 2743 vp = fp->f_vnode; 2744 vref(vp); 2745 FILEDESC_SUNLOCK(fdp); 2746 error = vn_fill_kinfo_vnode(vp, kif); 2747 vrele(vp); 2748 FILEDESC_SLOCK(fdp); 2749 return (error); 2750 } 2751 2752 static inline void 2753 vn_fill_junk(struct kinfo_file *kif) 2754 { 2755 size_t len, olen; 2756 2757 /* 2758 * Simulate vn_fullpath returning changing values for a given 2759 * vp during e.g. coredump. 2760 */ 2761 len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1; 2762 olen = strlen(kif->kf_path); 2763 if (len < olen) 2764 strcpy(&kif->kf_path[len - 1], "$"); 2765 else 2766 for (; olen < len; olen++) 2767 strcpy(&kif->kf_path[olen], "A"); 2768 } 2769 2770 int 2771 vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif) 2772 { 2773 struct vattr va; 2774 char *fullpath, *freepath; 2775 int error; 2776 2777 kif->kf_un.kf_file.kf_file_type = vntype_to_kinfo(vp->v_type); 2778 freepath = NULL; 2779 fullpath = "-"; 2780 error = vn_fullpath(vp, &fullpath, &freepath); 2781 if (error == 0) { 2782 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path)); 2783 } 2784 if (freepath != NULL) 2785 free(freepath, M_TEMP); 2786 2787 KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path, 2788 vn_fill_junk(kif); 2789 ); 2790 2791 /* 2792 * Retrieve vnode attributes. 2793 */ 2794 va.va_fsid = VNOVAL; 2795 va.va_rdev = NODEV; 2796 vn_lock(vp, LK_SHARED | LK_RETRY); 2797 error = VOP_GETATTR(vp, &va, curthread->td_ucred); 2798 VOP_UNLOCK(vp); 2799 if (error != 0) 2800 return (error); 2801 if (va.va_fsid != VNOVAL) 2802 kif->kf_un.kf_file.kf_file_fsid = va.va_fsid; 2803 else 2804 kif->kf_un.kf_file.kf_file_fsid = 2805 vp->v_mount->mnt_stat.f_fsid.val[0]; 2806 kif->kf_un.kf_file.kf_file_fsid_freebsd11 = 2807 kif->kf_un.kf_file.kf_file_fsid; /* truncate */ 2808 kif->kf_un.kf_file.kf_file_fileid = va.va_fileid; 2809 kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode); 2810 kif->kf_un.kf_file.kf_file_size = va.va_size; 2811 kif->kf_un.kf_file.kf_file_rdev = va.va_rdev; 2812 kif->kf_un.kf_file.kf_file_rdev_freebsd11 = 2813 kif->kf_un.kf_file.kf_file_rdev; /* truncate */ 2814 kif->kf_un.kf_file.kf_file_nlink = va.va_nlink; 2815 return (0); 2816 } 2817 2818 int 2819 vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size, 2820 vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff, 2821 struct thread *td) 2822 { 2823 #ifdef HWPMC_HOOKS 2824 struct pmckern_map_in pkm; 2825 #endif 2826 struct mount *mp; 2827 struct vnode *vp; 2828 vm_object_t object; 2829 vm_prot_t maxprot; 2830 boolean_t writecounted; 2831 int error; 2832 2833 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \ 2834 defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) 2835 /* 2836 * POSIX shared-memory objects are defined to have 2837 * kernel persistence, and are not defined to support 2838 * read(2)/write(2) -- or even open(2). Thus, we can 2839 * use MAP_ASYNC to trade on-disk coherence for speed. 2840 * The shm_open(3) library routine turns on the FPOSIXSHM 2841 * flag to request this behavior. 2842 */ 2843 if ((fp->f_flag & FPOSIXSHM) != 0) 2844 flags |= MAP_NOSYNC; 2845 #endif 2846 vp = fp->f_vnode; 2847 2848 /* 2849 * Ensure that file and memory protections are 2850 * compatible. Note that we only worry about 2851 * writability if mapping is shared; in this case, 2852 * current and max prot are dictated by the open file. 2853 * XXX use the vnode instead? Problem is: what 2854 * credentials do we use for determination? What if 2855 * proc does a setuid? 2856 */ 2857 mp = vp->v_mount; 2858 if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) { 2859 maxprot = VM_PROT_NONE; 2860 if ((prot & VM_PROT_EXECUTE) != 0) 2861 return (EACCES); 2862 } else 2863 maxprot = VM_PROT_EXECUTE; 2864 if ((fp->f_flag & FREAD) != 0) 2865 maxprot |= VM_PROT_READ; 2866 else if ((prot & VM_PROT_READ) != 0) 2867 return (EACCES); 2868 2869 /* 2870 * If we are sharing potential changes via MAP_SHARED and we 2871 * are trying to get write permission although we opened it 2872 * without asking for it, bail out. 2873 */ 2874 if ((flags & MAP_SHARED) != 0) { 2875 if ((fp->f_flag & FWRITE) != 0) 2876 maxprot |= VM_PROT_WRITE; 2877 else if ((prot & VM_PROT_WRITE) != 0) 2878 return (EACCES); 2879 } else { 2880 maxprot |= VM_PROT_WRITE; 2881 cap_maxprot |= VM_PROT_WRITE; 2882 } 2883 maxprot &= cap_maxprot; 2884 2885 /* 2886 * For regular files and shared memory, POSIX requires that 2887 * the value of foff be a legitimate offset within the data 2888 * object. In particular, negative offsets are invalid. 2889 * Blocking negative offsets and overflows here avoids 2890 * possible wraparound or user-level access into reserved 2891 * ranges of the data object later. In contrast, POSIX does 2892 * not dictate how offsets are used by device drivers, so in 2893 * the case of a device mapping a negative offset is passed 2894 * on. 2895 */ 2896 if ( 2897 #ifdef _LP64 2898 size > OFF_MAX || 2899 #endif 2900 foff > OFF_MAX - size) 2901 return (EINVAL); 2902 2903 writecounted = FALSE; 2904 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp, 2905 &foff, &object, &writecounted); 2906 if (error != 0) 2907 return (error); 2908 error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object, 2909 foff, writecounted, td); 2910 if (error != 0) { 2911 /* 2912 * If this mapping was accounted for in the vnode's 2913 * writecount, then undo that now. 2914 */ 2915 if (writecounted) 2916 vm_pager_release_writecount(object, 0, size); 2917 vm_object_deallocate(object); 2918 } 2919 #ifdef HWPMC_HOOKS 2920 /* Inform hwpmc(4) if an executable is being mapped. */ 2921 if (PMC_HOOK_INSTALLED(PMC_FN_MMAP)) { 2922 if ((prot & VM_PROT_EXECUTE) != 0 && error == 0) { 2923 pkm.pm_file = vp; 2924 pkm.pm_address = (uintptr_t) *addr; 2925 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_MMAP, (void *) &pkm); 2926 } 2927 } 2928 #endif 2929 return (error); 2930 } 2931 2932 void 2933 vn_fsid(struct vnode *vp, struct vattr *va) 2934 { 2935 fsid_t *f; 2936 2937 f = &vp->v_mount->mnt_stat.f_fsid; 2938 va->va_fsid = (uint32_t)f->val[1]; 2939 va->va_fsid <<= sizeof(f->val[1]) * NBBY; 2940 va->va_fsid += (uint32_t)f->val[0]; 2941 } 2942 2943 int 2944 vn_fsync_buf(struct vnode *vp, int waitfor) 2945 { 2946 struct buf *bp, *nbp; 2947 struct bufobj *bo; 2948 struct mount *mp; 2949 int error, maxretry; 2950 2951 error = 0; 2952 maxretry = 10000; /* large, arbitrarily chosen */ 2953 mp = NULL; 2954 if (vp->v_type == VCHR) { 2955 VI_LOCK(vp); 2956 mp = vp->v_rdev->si_mountpt; 2957 VI_UNLOCK(vp); 2958 } 2959 bo = &vp->v_bufobj; 2960 BO_LOCK(bo); 2961 loop1: 2962 /* 2963 * MARK/SCAN initialization to avoid infinite loops. 2964 */ 2965 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) { 2966 bp->b_vflags &= ~BV_SCANNED; 2967 bp->b_error = 0; 2968 } 2969 2970 /* 2971 * Flush all dirty buffers associated with a vnode. 2972 */ 2973 loop2: 2974 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) { 2975 if ((bp->b_vflags & BV_SCANNED) != 0) 2976 continue; 2977 bp->b_vflags |= BV_SCANNED; 2978 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL)) { 2979 if (waitfor != MNT_WAIT) 2980 continue; 2981 if (BUF_LOCK(bp, 2982 LK_EXCLUSIVE | LK_INTERLOCK | LK_SLEEPFAIL, 2983 BO_LOCKPTR(bo)) != 0) { 2984 BO_LOCK(bo); 2985 goto loop1; 2986 } 2987 BO_LOCK(bo); 2988 } 2989 BO_UNLOCK(bo); 2990 KASSERT(bp->b_bufobj == bo, 2991 ("bp %p wrong b_bufobj %p should be %p", 2992 bp, bp->b_bufobj, bo)); 2993 if ((bp->b_flags & B_DELWRI) == 0) 2994 panic("fsync: not dirty"); 2995 if ((vp->v_object != NULL) && (bp->b_flags & B_CLUSTEROK)) { 2996 vfs_bio_awrite(bp); 2997 } else { 2998 bremfree(bp); 2999 bawrite(bp); 3000 } 3001 if (maxretry < 1000) 3002 pause("dirty", hz < 1000 ? 1 : hz / 1000); 3003 BO_LOCK(bo); 3004 goto loop2; 3005 } 3006 3007 /* 3008 * If synchronous the caller expects us to completely resolve all 3009 * dirty buffers in the system. Wait for in-progress I/O to 3010 * complete (which could include background bitmap writes), then 3011 * retry if dirty blocks still exist. 3012 */ 3013 if (waitfor == MNT_WAIT) { 3014 bufobj_wwait(bo, 0, 0); 3015 if (bo->bo_dirty.bv_cnt > 0) { 3016 /* 3017 * If we are unable to write any of these buffers 3018 * then we fail now rather than trying endlessly 3019 * to write them out. 3020 */ 3021 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) 3022 if ((error = bp->b_error) != 0) 3023 break; 3024 if ((mp != NULL && mp->mnt_secondary_writes > 0) || 3025 (error == 0 && --maxretry >= 0)) 3026 goto loop1; 3027 if (error == 0) 3028 error = EAGAIN; 3029 } 3030 } 3031 BO_UNLOCK(bo); 3032 if (error != 0) 3033 vn_printf(vp, "fsync: giving up on dirty (error = %d) ", error); 3034 3035 return (error); 3036 } 3037 3038 /* 3039 * Copies a byte range from invp to outvp. Calls VOP_COPY_FILE_RANGE() 3040 * or vn_generic_copy_file_range() after rangelocking the byte ranges, 3041 * to do the actual copy. 3042 * vn_generic_copy_file_range() is factored out, so it can be called 3043 * from a VOP_COPY_FILE_RANGE() call as well, but handles vnodes from 3044 * different file systems. 3045 */ 3046 int 3047 vn_copy_file_range(struct vnode *invp, off_t *inoffp, struct vnode *outvp, 3048 off_t *outoffp, size_t *lenp, unsigned int flags, struct ucred *incred, 3049 struct ucred *outcred, struct thread *fsize_td) 3050 { 3051 int error; 3052 size_t len; 3053 uint64_t uval; 3054 3055 len = *lenp; 3056 *lenp = 0; /* For error returns. */ 3057 error = 0; 3058 3059 /* Do some sanity checks on the arguments. */ 3060 if (invp->v_type == VDIR || outvp->v_type == VDIR) 3061 error = EISDIR; 3062 else if (*inoffp < 0 || *outoffp < 0 || 3063 invp->v_type != VREG || outvp->v_type != VREG) 3064 error = EINVAL; 3065 if (error != 0) 3066 goto out; 3067 3068 /* Ensure offset + len does not wrap around. */ 3069 uval = *inoffp; 3070 uval += len; 3071 if (uval > INT64_MAX) 3072 len = INT64_MAX - *inoffp; 3073 uval = *outoffp; 3074 uval += len; 3075 if (uval > INT64_MAX) 3076 len = INT64_MAX - *outoffp; 3077 if (len == 0) 3078 goto out; 3079 3080 /* 3081 * If the two vnode are for the same file system, call 3082 * VOP_COPY_FILE_RANGE(), otherwise call vn_generic_copy_file_range() 3083 * which can handle copies across multiple file systems. 3084 */ 3085 *lenp = len; 3086 if (invp->v_mount == outvp->v_mount) 3087 error = VOP_COPY_FILE_RANGE(invp, inoffp, outvp, outoffp, 3088 lenp, flags, incred, outcred, fsize_td); 3089 else 3090 error = vn_generic_copy_file_range(invp, inoffp, outvp, 3091 outoffp, lenp, flags, incred, outcred, fsize_td); 3092 out: 3093 return (error); 3094 } 3095 3096 /* 3097 * Test len bytes of data starting at dat for all bytes == 0. 3098 * Return true if all bytes are zero, false otherwise. 3099 * Expects dat to be well aligned. 3100 */ 3101 static bool 3102 mem_iszero(void *dat, int len) 3103 { 3104 int i; 3105 const u_int *p; 3106 const char *cp; 3107 3108 for (p = dat; len > 0; len -= sizeof(*p), p++) { 3109 if (len >= sizeof(*p)) { 3110 if (*p != 0) 3111 return (false); 3112 } else { 3113 cp = (const char *)p; 3114 for (i = 0; i < len; i++, cp++) 3115 if (*cp != '\0') 3116 return (false); 3117 } 3118 } 3119 return (true); 3120 } 3121 3122 /* 3123 * Look for a hole in the output file and, if found, adjust *outoffp 3124 * and *xferp to skip past the hole. 3125 * *xferp is the entire hole length to be written and xfer2 is how many bytes 3126 * to be written as 0's upon return. 3127 */ 3128 static off_t 3129 vn_skip_hole(struct vnode *outvp, off_t xfer2, off_t *outoffp, off_t *xferp, 3130 off_t *dataoffp, off_t *holeoffp, struct ucred *cred) 3131 { 3132 int error; 3133 off_t delta; 3134 3135 if (*holeoffp == 0 || *holeoffp <= *outoffp) { 3136 *dataoffp = *outoffp; 3137 error = VOP_IOCTL(outvp, FIOSEEKDATA, dataoffp, 0, cred, 3138 curthread); 3139 if (error == 0) { 3140 *holeoffp = *dataoffp; 3141 error = VOP_IOCTL(outvp, FIOSEEKHOLE, holeoffp, 0, cred, 3142 curthread); 3143 } 3144 if (error != 0 || *holeoffp == *dataoffp) { 3145 /* 3146 * Since outvp is unlocked, it may be possible for 3147 * another thread to do a truncate(), lseek(), write() 3148 * creating a hole at startoff between the above 3149 * VOP_IOCTL() calls, if the other thread does not do 3150 * rangelocking. 3151 * If that happens, *holeoffp == *dataoffp and finding 3152 * the hole has failed, so disable vn_skip_hole(). 3153 */ 3154 *holeoffp = -1; /* Disable use of vn_skip_hole(). */ 3155 return (xfer2); 3156 } 3157 KASSERT(*dataoffp >= *outoffp, 3158 ("vn_skip_hole: dataoff=%jd < outoff=%jd", 3159 (intmax_t)*dataoffp, (intmax_t)*outoffp)); 3160 KASSERT(*holeoffp > *dataoffp, 3161 ("vn_skip_hole: holeoff=%jd <= dataoff=%jd", 3162 (intmax_t)*holeoffp, (intmax_t)*dataoffp)); 3163 } 3164 3165 /* 3166 * If there is a hole before the data starts, advance *outoffp and 3167 * *xferp past the hole. 3168 */ 3169 if (*dataoffp > *outoffp) { 3170 delta = *dataoffp - *outoffp; 3171 if (delta >= *xferp) { 3172 /* Entire *xferp is a hole. */ 3173 *outoffp += *xferp; 3174 *xferp = 0; 3175 return (0); 3176 } 3177 *xferp -= delta; 3178 *outoffp += delta; 3179 xfer2 = MIN(xfer2, *xferp); 3180 } 3181 3182 /* 3183 * If a hole starts before the end of this xfer2, reduce this xfer2 so 3184 * that the write ends at the start of the hole. 3185 * *holeoffp should always be greater than *outoffp, but for the 3186 * non-INVARIANTS case, check this to make sure xfer2 remains a sane 3187 * value. 3188 */ 3189 if (*holeoffp > *outoffp && *holeoffp < *outoffp + xfer2) 3190 xfer2 = *holeoffp - *outoffp; 3191 return (xfer2); 3192 } 3193 3194 /* 3195 * Write an xfer sized chunk to outvp in blksize blocks from dat. 3196 * dat is a maximum of blksize in length and can be written repeatedly in 3197 * the chunk. 3198 * If growfile == true, just grow the file via vn_truncate_locked() instead 3199 * of doing actual writes. 3200 * If checkhole == true, a hole is being punched, so skip over any hole 3201 * already in the output file. 3202 */ 3203 static int 3204 vn_write_outvp(struct vnode *outvp, char *dat, off_t outoff, off_t xfer, 3205 u_long blksize, bool growfile, bool checkhole, struct ucred *cred) 3206 { 3207 struct mount *mp; 3208 off_t dataoff, holeoff, xfer2; 3209 int error; 3210 3211 /* 3212 * Loop around doing writes of blksize until write has been completed. 3213 * Lock/unlock on each loop iteration so that a bwillwrite() can be 3214 * done for each iteration, since the xfer argument can be very 3215 * large if there is a large hole to punch in the output file. 3216 */ 3217 error = 0; 3218 holeoff = 0; 3219 do { 3220 xfer2 = MIN(xfer, blksize); 3221 if (checkhole) { 3222 /* 3223 * Punching a hole. Skip writing if there is 3224 * already a hole in the output file. 3225 */ 3226 xfer2 = vn_skip_hole(outvp, xfer2, &outoff, &xfer, 3227 &dataoff, &holeoff, cred); 3228 if (xfer == 0) 3229 break; 3230 if (holeoff < 0) 3231 checkhole = false; 3232 KASSERT(xfer2 > 0, ("vn_write_outvp: xfer2=%jd", 3233 (intmax_t)xfer2)); 3234 } 3235 bwillwrite(); 3236 mp = NULL; 3237 error = vn_start_write(outvp, &mp, V_WAIT); 3238 if (error != 0) 3239 break; 3240 if (growfile) { 3241 error = vn_lock(outvp, LK_EXCLUSIVE); 3242 if (error == 0) { 3243 error = vn_truncate_locked(outvp, outoff + xfer, 3244 false, cred); 3245 VOP_UNLOCK(outvp); 3246 } 3247 } else { 3248 error = vn_lock(outvp, vn_lktype_write(mp, outvp)); 3249 if (error == 0) { 3250 error = vn_rdwr(UIO_WRITE, outvp, dat, xfer2, 3251 outoff, UIO_SYSSPACE, IO_NODELOCKED, 3252 curthread->td_ucred, cred, NULL, curthread); 3253 outoff += xfer2; 3254 xfer -= xfer2; 3255 VOP_UNLOCK(outvp); 3256 } 3257 } 3258 if (mp != NULL) 3259 vn_finished_write(mp); 3260 } while (!growfile && xfer > 0 && error == 0); 3261 return (error); 3262 } 3263 3264 /* 3265 * Copy a byte range of one file to another. This function can handle the 3266 * case where invp and outvp are on different file systems. 3267 * It can also be called by a VOP_COPY_FILE_RANGE() to do the work, if there 3268 * is no better file system specific way to do it. 3269 */ 3270 int 3271 vn_generic_copy_file_range(struct vnode *invp, off_t *inoffp, 3272 struct vnode *outvp, off_t *outoffp, size_t *lenp, unsigned int flags, 3273 struct ucred *incred, struct ucred *outcred, struct thread *fsize_td) 3274 { 3275 struct mount *mp; 3276 off_t startoff, endoff, xfer, xfer2; 3277 u_long blksize; 3278 int error, interrupted; 3279 bool cantseek, readzeros, eof, lastblock, holetoeof; 3280 ssize_t aresid, r = 0; 3281 size_t copylen, len, savlen; 3282 off_t insize, outsize; 3283 char *dat; 3284 long holein, holeout; 3285 struct timespec curts, endts; 3286 3287 holein = holeout = 0; 3288 savlen = len = *lenp; 3289 error = 0; 3290 interrupted = 0; 3291 dat = NULL; 3292 3293 error = vn_lock(invp, LK_SHARED); 3294 if (error != 0) 3295 goto out; 3296 if (VOP_PATHCONF(invp, _PC_MIN_HOLE_SIZE, &holein) != 0) 3297 holein = 0; 3298 if (holein > 0) 3299 error = vn_getsize_locked(invp, &insize, incred); 3300 VOP_UNLOCK(invp); 3301 if (error != 0) 3302 goto out; 3303 3304 mp = NULL; 3305 error = vn_start_write(outvp, &mp, V_WAIT); 3306 if (error == 0) 3307 error = vn_lock(outvp, LK_EXCLUSIVE); 3308 if (error == 0) { 3309 /* 3310 * If fsize_td != NULL, do a vn_rlimit_fsizex() call, 3311 * now that outvp is locked. 3312 */ 3313 if (fsize_td != NULL) { 3314 struct uio io; 3315 3316 io.uio_offset = *outoffp; 3317 io.uio_resid = len; 3318 error = vn_rlimit_fsizex(outvp, &io, 0, &r, fsize_td); 3319 len = savlen = io.uio_resid; 3320 /* 3321 * No need to call vn_rlimit_fsizex_res before return, 3322 * since the uio is local. 3323 */ 3324 } 3325 if (VOP_PATHCONF(outvp, _PC_MIN_HOLE_SIZE, &holeout) != 0) 3326 holeout = 0; 3327 /* 3328 * Holes that are past EOF do not need to be written as a block 3329 * of zero bytes. So, truncate the output file as far as 3330 * possible and then use size to decide if writing 0 3331 * bytes is necessary in the loop below. 3332 */ 3333 if (error == 0) 3334 error = vn_getsize_locked(outvp, &outsize, outcred); 3335 if (error == 0 && outsize > *outoffp && outsize <= *outoffp + len) { 3336 #ifdef MAC 3337 error = mac_vnode_check_write(curthread->td_ucred, 3338 outcred, outvp); 3339 if (error == 0) 3340 #endif 3341 error = vn_truncate_locked(outvp, *outoffp, 3342 false, outcred); 3343 if (error == 0) 3344 outsize = *outoffp; 3345 } 3346 VOP_UNLOCK(outvp); 3347 } 3348 if (mp != NULL) 3349 vn_finished_write(mp); 3350 if (error != 0) 3351 goto out; 3352 3353 if (holein == 0 && holeout > 0) { 3354 /* 3355 * For this special case, the input data will be scanned 3356 * for blocks of all 0 bytes. For these blocks, the 3357 * write can be skipped for the output file to create 3358 * an unallocated region. 3359 * Therefore, use the appropriate size for the output file. 3360 */ 3361 blksize = holeout; 3362 if (blksize <= 512) { 3363 /* 3364 * Use f_iosize, since ZFS reports a _PC_MIN_HOLE_SIZE 3365 * of 512, although it actually only creates 3366 * unallocated regions for blocks >= f_iosize. 3367 */ 3368 blksize = outvp->v_mount->mnt_stat.f_iosize; 3369 } 3370 } else { 3371 /* 3372 * Use the larger of the two f_iosize values. If they are 3373 * not the same size, one will normally be an exact multiple of 3374 * the other, since they are both likely to be a power of 2. 3375 */ 3376 blksize = MAX(invp->v_mount->mnt_stat.f_iosize, 3377 outvp->v_mount->mnt_stat.f_iosize); 3378 } 3379 3380 /* Clip to sane limits. */ 3381 if (blksize < 4096) 3382 blksize = 4096; 3383 else if (blksize > maxphys) 3384 blksize = maxphys; 3385 dat = malloc(blksize, M_TEMP, M_WAITOK); 3386 3387 /* 3388 * If VOP_IOCTL(FIOSEEKHOLE) works for invp, use it and FIOSEEKDATA 3389 * to find holes. Otherwise, just scan the read block for all 0s 3390 * in the inner loop where the data copying is done. 3391 * Note that some file systems such as NFSv3, NFSv4.0 and NFSv4.1 may 3392 * support holes on the server, but do not support FIOSEEKHOLE. 3393 * The kernel flag COPY_FILE_RANGE_TIMEO1SEC is used to indicate 3394 * that this function should return after 1second with a partial 3395 * completion. 3396 */ 3397 if ((flags & COPY_FILE_RANGE_TIMEO1SEC) != 0) { 3398 getnanouptime(&endts); 3399 endts.tv_sec++; 3400 } else 3401 timespecclear(&endts); 3402 holetoeof = eof = false; 3403 while (len > 0 && error == 0 && !eof && interrupted == 0) { 3404 endoff = 0; /* To shut up compilers. */ 3405 cantseek = true; 3406 startoff = *inoffp; 3407 copylen = len; 3408 3409 /* 3410 * Find the next data area. If there is just a hole to EOF, 3411 * FIOSEEKDATA should fail with ENXIO. 3412 * (I do not know if any file system will report a hole to 3413 * EOF via FIOSEEKHOLE, but I am pretty sure FIOSEEKDATA 3414 * will fail for those file systems.) 3415 * 3416 * For input files that don't support FIOSEEKDATA/FIOSEEKHOLE, 3417 * the code just falls through to the inner copy loop. 3418 */ 3419 error = EINVAL; 3420 if (holein > 0) { 3421 error = VOP_IOCTL(invp, FIOSEEKDATA, &startoff, 0, 3422 incred, curthread); 3423 if (error == ENXIO) { 3424 startoff = endoff = insize; 3425 eof = holetoeof = true; 3426 error = 0; 3427 } 3428 } 3429 if (error == 0 && !holetoeof) { 3430 endoff = startoff; 3431 error = VOP_IOCTL(invp, FIOSEEKHOLE, &endoff, 0, 3432 incred, curthread); 3433 /* 3434 * Since invp is unlocked, it may be possible for 3435 * another thread to do a truncate(), lseek(), write() 3436 * creating a hole at startoff between the above 3437 * VOP_IOCTL() calls, if the other thread does not do 3438 * rangelocking. 3439 * If that happens, startoff == endoff and finding 3440 * the hole has failed, so set an error. 3441 */ 3442 if (error == 0 && startoff == endoff) 3443 error = EINVAL; /* Any error. Reset to 0. */ 3444 } 3445 if (error == 0) { 3446 if (startoff > *inoffp) { 3447 /* Found hole before data block. */ 3448 xfer = MIN(startoff - *inoffp, len); 3449 if (*outoffp < outsize) { 3450 /* Must write 0s to punch hole. */ 3451 xfer2 = MIN(outsize - *outoffp, 3452 xfer); 3453 memset(dat, 0, MIN(xfer2, blksize)); 3454 error = vn_write_outvp(outvp, dat, 3455 *outoffp, xfer2, blksize, false, 3456 holeout > 0, outcred); 3457 } 3458 3459 if (error == 0 && *outoffp + xfer > 3460 outsize && (xfer == len || holetoeof)) { 3461 /* Grow output file (hole at end). */ 3462 error = vn_write_outvp(outvp, dat, 3463 *outoffp, xfer, blksize, true, 3464 false, outcred); 3465 } 3466 if (error == 0) { 3467 *inoffp += xfer; 3468 *outoffp += xfer; 3469 len -= xfer; 3470 if (len < savlen) { 3471 interrupted = sig_intr(); 3472 if (timespecisset(&endts) && 3473 interrupted == 0) { 3474 getnanouptime(&curts); 3475 if (timespeccmp(&curts, 3476 &endts, >=)) 3477 interrupted = 3478 EINTR; 3479 } 3480 } 3481 } 3482 } 3483 copylen = MIN(len, endoff - startoff); 3484 cantseek = false; 3485 } else { 3486 cantseek = true; 3487 startoff = *inoffp; 3488 copylen = len; 3489 error = 0; 3490 } 3491 3492 xfer = blksize; 3493 if (cantseek) { 3494 /* 3495 * Set first xfer to end at a block boundary, so that 3496 * holes are more likely detected in the loop below via 3497 * the for all bytes 0 method. 3498 */ 3499 xfer -= (*inoffp % blksize); 3500 } 3501 /* Loop copying the data block. */ 3502 while (copylen > 0 && error == 0 && !eof && interrupted == 0) { 3503 if (copylen < xfer) 3504 xfer = copylen; 3505 error = vn_lock(invp, LK_SHARED); 3506 if (error != 0) 3507 goto out; 3508 error = vn_rdwr(UIO_READ, invp, dat, xfer, 3509 startoff, UIO_SYSSPACE, IO_NODELOCKED, 3510 curthread->td_ucred, incred, &aresid, 3511 curthread); 3512 VOP_UNLOCK(invp); 3513 lastblock = false; 3514 if (error == 0 && aresid > 0) { 3515 /* Stop the copy at EOF on the input file. */ 3516 xfer -= aresid; 3517 eof = true; 3518 lastblock = true; 3519 } 3520 if (error == 0) { 3521 /* 3522 * Skip the write for holes past the initial EOF 3523 * of the output file, unless this is the last 3524 * write of the output file at EOF. 3525 */ 3526 readzeros = cantseek ? mem_iszero(dat, xfer) : 3527 false; 3528 if (xfer == len) 3529 lastblock = true; 3530 if (!cantseek || *outoffp < outsize || 3531 lastblock || !readzeros) 3532 error = vn_write_outvp(outvp, dat, 3533 *outoffp, xfer, blksize, 3534 readzeros && lastblock && 3535 *outoffp >= outsize, false, 3536 outcred); 3537 if (error == 0) { 3538 *inoffp += xfer; 3539 startoff += xfer; 3540 *outoffp += xfer; 3541 copylen -= xfer; 3542 len -= xfer; 3543 if (len < savlen) { 3544 interrupted = sig_intr(); 3545 if (timespecisset(&endts) && 3546 interrupted == 0) { 3547 getnanouptime(&curts); 3548 if (timespeccmp(&curts, 3549 &endts, >=)) 3550 interrupted = 3551 EINTR; 3552 } 3553 } 3554 } 3555 } 3556 xfer = blksize; 3557 } 3558 } 3559 out: 3560 *lenp = savlen - len; 3561 free(dat, M_TEMP); 3562 return (error); 3563 } 3564 3565 static int 3566 vn_fallocate(struct file *fp, off_t offset, off_t len, struct thread *td) 3567 { 3568 struct mount *mp; 3569 struct vnode *vp; 3570 off_t olen, ooffset; 3571 int error; 3572 #ifdef AUDIT 3573 int audited_vnode1 = 0; 3574 #endif 3575 3576 vp = fp->f_vnode; 3577 if (vp->v_type != VREG) 3578 return (ENODEV); 3579 3580 /* Allocating blocks may take a long time, so iterate. */ 3581 for (;;) { 3582 olen = len; 3583 ooffset = offset; 3584 3585 bwillwrite(); 3586 mp = NULL; 3587 error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH); 3588 if (error != 0) 3589 break; 3590 error = vn_lock(vp, LK_EXCLUSIVE); 3591 if (error != 0) { 3592 vn_finished_write(mp); 3593 break; 3594 } 3595 #ifdef AUDIT 3596 if (!audited_vnode1) { 3597 AUDIT_ARG_VNODE1(vp); 3598 audited_vnode1 = 1; 3599 } 3600 #endif 3601 #ifdef MAC 3602 error = mac_vnode_check_write(td->td_ucred, fp->f_cred, vp); 3603 if (error == 0) 3604 #endif 3605 error = VOP_ALLOCATE(vp, &offset, &len, 0, 3606 td->td_ucred); 3607 VOP_UNLOCK(vp); 3608 vn_finished_write(mp); 3609 3610 if (olen + ooffset != offset + len) { 3611 panic("offset + len changed from %jx/%jx to %jx/%jx", 3612 ooffset, olen, offset, len); 3613 } 3614 if (error != 0 || len == 0) 3615 break; 3616 KASSERT(olen > len, ("Iteration did not make progress?")); 3617 maybe_yield(); 3618 } 3619 3620 return (error); 3621 } 3622 3623 static int 3624 vn_deallocate_impl(struct vnode *vp, off_t *offset, off_t *length, int flags, 3625 int ioflag, struct ucred *cred, struct ucred *active_cred, 3626 struct ucred *file_cred) 3627 { 3628 struct mount *mp; 3629 void *rl_cookie; 3630 off_t off, len; 3631 int error; 3632 #ifdef AUDIT 3633 bool audited_vnode1 = false; 3634 #endif 3635 3636 rl_cookie = NULL; 3637 error = 0; 3638 mp = NULL; 3639 off = *offset; 3640 len = *length; 3641 3642 if ((ioflag & (IO_NODELOCKED | IO_RANGELOCKED)) == 0) 3643 rl_cookie = vn_rangelock_wlock(vp, off, off + len); 3644 while (len > 0 && error == 0) { 3645 /* 3646 * Try to deallocate the longest range in one pass. 3647 * In case a pass takes too long to be executed, it returns 3648 * partial result. The residue will be proceeded in the next 3649 * pass. 3650 */ 3651 3652 if ((ioflag & IO_NODELOCKED) == 0) { 3653 bwillwrite(); 3654 if ((error = vn_start_write(vp, &mp, 3655 V_WAIT | V_PCATCH)) != 0) 3656 goto out; 3657 vn_lock(vp, vn_lktype_write(mp, vp) | LK_RETRY); 3658 } 3659 #ifdef AUDIT 3660 if (!audited_vnode1) { 3661 AUDIT_ARG_VNODE1(vp); 3662 audited_vnode1 = true; 3663 } 3664 #endif 3665 3666 #ifdef MAC 3667 if ((ioflag & IO_NOMACCHECK) == 0) 3668 error = mac_vnode_check_write(active_cred, file_cred, 3669 vp); 3670 #endif 3671 if (error == 0) 3672 error = VOP_DEALLOCATE(vp, &off, &len, flags, ioflag, 3673 cred); 3674 3675 if ((ioflag & IO_NODELOCKED) == 0) { 3676 VOP_UNLOCK(vp); 3677 if (mp != NULL) { 3678 vn_finished_write(mp); 3679 mp = NULL; 3680 } 3681 } 3682 if (error == 0 && len != 0) 3683 maybe_yield(); 3684 } 3685 out: 3686 if (rl_cookie != NULL) 3687 vn_rangelock_unlock(vp, rl_cookie); 3688 *offset = off; 3689 *length = len; 3690 return (error); 3691 } 3692 3693 /* 3694 * This function is supposed to be used in the situations where the deallocation 3695 * is not triggered by a user request. 3696 */ 3697 int 3698 vn_deallocate(struct vnode *vp, off_t *offset, off_t *length, int flags, 3699 int ioflag, struct ucred *active_cred, struct ucred *file_cred) 3700 { 3701 struct ucred *cred; 3702 3703 if (*offset < 0 || *length <= 0 || *length > OFF_MAX - *offset || 3704 flags != 0) 3705 return (EINVAL); 3706 if (vp->v_type != VREG) 3707 return (ENODEV); 3708 3709 cred = file_cred != NOCRED ? file_cred : active_cred; 3710 return (vn_deallocate_impl(vp, offset, length, flags, ioflag, cred, 3711 active_cred, file_cred)); 3712 } 3713 3714 static int 3715 vn_fspacectl(struct file *fp, int cmd, off_t *offset, off_t *length, int flags, 3716 struct ucred *active_cred, struct thread *td) 3717 { 3718 int error; 3719 struct vnode *vp; 3720 int ioflag; 3721 3722 KASSERT(cmd == SPACECTL_DEALLOC, ("vn_fspacectl: Invalid cmd")); 3723 KASSERT((flags & ~SPACECTL_F_SUPPORTED) == 0, 3724 ("vn_fspacectl: non-zero flags")); 3725 KASSERT(*offset >= 0 && *length > 0 && *length <= OFF_MAX - *offset, 3726 ("vn_fspacectl: offset/length overflow or underflow")); 3727 vp = fp->f_vnode; 3728 3729 if (vp->v_type != VREG) 3730 return (ENODEV); 3731 3732 ioflag = get_write_ioflag(fp); 3733 3734 switch (cmd) { 3735 case SPACECTL_DEALLOC: 3736 error = vn_deallocate_impl(vp, offset, length, flags, ioflag, 3737 active_cred, active_cred, fp->f_cred); 3738 break; 3739 default: 3740 panic("vn_fspacectl: unknown cmd %d", cmd); 3741 } 3742 3743 return (error); 3744 } 3745 3746 /* 3747 * Keep this assert as long as sizeof(struct dirent) is used as the maximum 3748 * entry size. 3749 */ 3750 _Static_assert(_GENERIC_MAXDIRSIZ == sizeof(struct dirent), 3751 "'struct dirent' size must be a multiple of its alignment " 3752 "(see _GENERIC_DIRLEN())"); 3753 3754 /* 3755 * Returns successive directory entries through some caller's provided buffer. 3756 * 3757 * This function automatically refills the provided buffer with calls to 3758 * VOP_READDIR() (after MAC permission checks). 3759 * 3760 * 'td' is used for credentials and passed to uiomove(). 'dirbuf' is the 3761 * caller's buffer to fill and 'dirbuflen' its allocated size. 'dirbuf' must 3762 * be properly aligned to access 'struct dirent' structures and 'dirbuflen' 3763 * must be greater than GENERIC_MAXDIRSIZ to avoid VOP_READDIR() returning 3764 * EINVAL (the latter is not a strong guarantee (yet); but EINVAL will always 3765 * be returned if this requirement is not verified). '*dpp' points to the 3766 * current directory entry in the buffer and '*len' contains the remaining 3767 * valid bytes in 'dirbuf' after 'dpp' (including the pointed entry). 3768 * 3769 * At first call (or when restarting the read), '*len' must have been set to 0, 3770 * '*off' to 0 (or any valid start offset) and '*eofflag' to 0. There are no 3771 * more entries as soon as '*len' is 0 after a call that returned 0. Calling 3772 * again this function after such a condition is considered an error and EINVAL 3773 * will be returned. Other possible error codes are those of VOP_READDIR(), 3774 * EINTEGRITY if the returned entries do not pass coherency tests, or EINVAL 3775 * (bad call). All errors are unrecoverable, i.e., the state ('*len', '*off' 3776 * and '*eofflag') must be re-initialized before a subsequent call. On error 3777 * or at end of directory, '*dpp' is reset to NULL. 3778 * 3779 * '*len', '*off' and '*eofflag' are internal state the caller should not 3780 * tamper with except as explained above. '*off' is the next directory offset 3781 * to read from to refill the buffer. '*eofflag' is set to 0 or 1 by the last 3782 * internal call to VOP_READDIR() that returned without error, indicating 3783 * whether it reached the end of the directory, and to 2 by this function after 3784 * all entries have been read. 3785 */ 3786 int 3787 vn_dir_next_dirent(struct vnode *vp, struct thread *td, 3788 char *dirbuf, size_t dirbuflen, 3789 struct dirent **dpp, size_t *len, off_t *off, int *eofflag) 3790 { 3791 struct dirent *dp = NULL; 3792 int reclen; 3793 int error; 3794 struct uio uio; 3795 struct iovec iov; 3796 3797 ASSERT_VOP_LOCKED(vp, "vnode not locked"); 3798 VNASSERT(vp->v_type == VDIR, vp, ("vnode is not a directory")); 3799 MPASS2((uintptr_t)dirbuf < (uintptr_t)dirbuf + dirbuflen, 3800 "Address space overflow"); 3801 3802 if (__predict_false(dirbuflen < GENERIC_MAXDIRSIZ)) { 3803 /* Don't take any chances in this case */ 3804 error = EINVAL; 3805 goto out; 3806 } 3807 3808 if (*len != 0) { 3809 dp = *dpp; 3810 3811 /* 3812 * The caller continued to call us after an error (we set dp to 3813 * NULL in a previous iteration). Bail out right now. 3814 */ 3815 if (__predict_false(dp == NULL)) 3816 return (EINVAL); 3817 3818 MPASS(*len <= dirbuflen); 3819 MPASS2((uintptr_t)dirbuf <= (uintptr_t)dp && 3820 (uintptr_t)dp + *len <= (uintptr_t)dirbuf + dirbuflen, 3821 "Filled range not inside buffer"); 3822 3823 reclen = dp->d_reclen; 3824 if (reclen >= *len) { 3825 /* End of buffer reached */ 3826 *len = 0; 3827 } else { 3828 dp = (struct dirent *)((char *)dp + reclen); 3829 *len -= reclen; 3830 } 3831 } 3832 3833 if (*len == 0) { 3834 dp = NULL; 3835 3836 /* Have to refill. */ 3837 switch (*eofflag) { 3838 case 0: 3839 break; 3840 3841 case 1: 3842 /* Nothing more to read. */ 3843 *eofflag = 2; /* Remember the caller reached EOF. */ 3844 goto success; 3845 3846 default: 3847 /* The caller didn't test for EOF. */ 3848 error = EINVAL; 3849 goto out; 3850 } 3851 3852 iov.iov_base = dirbuf; 3853 iov.iov_len = dirbuflen; 3854 3855 uio.uio_iov = &iov; 3856 uio.uio_iovcnt = 1; 3857 uio.uio_offset = *off; 3858 uio.uio_resid = dirbuflen; 3859 uio.uio_segflg = UIO_SYSSPACE; 3860 uio.uio_rw = UIO_READ; 3861 uio.uio_td = td; 3862 3863 #ifdef MAC 3864 error = mac_vnode_check_readdir(td->td_ucred, vp); 3865 if (error == 0) 3866 #endif 3867 error = VOP_READDIR(vp, &uio, td->td_ucred, eofflag, 3868 NULL, NULL); 3869 if (error != 0) 3870 goto out; 3871 3872 *len = dirbuflen - uio.uio_resid; 3873 *off = uio.uio_offset; 3874 3875 if (*len == 0) { 3876 /* Sanity check on INVARIANTS. */ 3877 MPASS(*eofflag != 0); 3878 *eofflag = 1; 3879 goto success; 3880 } 3881 3882 /* 3883 * Normalize the flag returned by VOP_READDIR(), since we use 2 3884 * as a sentinel value. 3885 */ 3886 if (*eofflag != 0) 3887 *eofflag = 1; 3888 3889 dp = (struct dirent *)dirbuf; 3890 } 3891 3892 if (__predict_false(*len < GENERIC_MINDIRSIZ || 3893 dp->d_reclen < GENERIC_MINDIRSIZ)) { 3894 error = EINTEGRITY; 3895 dp = NULL; 3896 goto out; 3897 } 3898 3899 success: 3900 error = 0; 3901 out: 3902 *dpp = dp; 3903 return (error); 3904 } 3905 3906 /* 3907 * Checks whether a directory is empty or not. 3908 * 3909 * If the directory is empty, returns 0, and if it is not, ENOTEMPTY. Other 3910 * values are genuine errors preventing the check. 3911 */ 3912 int 3913 vn_dir_check_empty(struct vnode *vp) 3914 { 3915 struct thread *const td = curthread; 3916 char *dirbuf; 3917 size_t dirbuflen, len; 3918 off_t off; 3919 int eofflag, error; 3920 struct dirent *dp; 3921 struct vattr va; 3922 3923 ASSERT_VOP_LOCKED(vp, "vfs_emptydir"); 3924 VNPASS(vp->v_type == VDIR, vp); 3925 3926 error = VOP_GETATTR(vp, &va, td->td_ucred); 3927 if (error != 0) 3928 return (error); 3929 3930 dirbuflen = max(DEV_BSIZE, GENERIC_MAXDIRSIZ); 3931 if (dirbuflen < va.va_blocksize) 3932 dirbuflen = va.va_blocksize; 3933 dirbuf = malloc(dirbuflen, M_TEMP, M_WAITOK); 3934 3935 len = 0; 3936 off = 0; 3937 eofflag = 0; 3938 3939 for (;;) { 3940 error = vn_dir_next_dirent(vp, td, dirbuf, dirbuflen, 3941 &dp, &len, &off, &eofflag); 3942 if (error != 0) 3943 goto end; 3944 3945 if (len == 0) { 3946 /* EOF */ 3947 error = 0; 3948 goto end; 3949 } 3950 3951 /* 3952 * Skip whiteouts. Unionfs operates on filesystems only and 3953 * not on hierarchies, so these whiteouts would be shadowed on 3954 * the system hierarchy but not for a union using the 3955 * filesystem of their directories as the upper layer. 3956 * Additionally, unionfs currently transparently exposes 3957 * union-specific metadata of its upper layer, meaning that 3958 * whiteouts can be seen through the union view in empty 3959 * directories. Taking into account these whiteouts would then 3960 * prevent mounting another filesystem on such effectively 3961 * empty directories. 3962 */ 3963 if (dp->d_type == DT_WHT) 3964 continue; 3965 3966 /* 3967 * Any file in the directory which is not '.' or '..' indicates 3968 * the directory is not empty. 3969 */ 3970 switch (dp->d_namlen) { 3971 case 2: 3972 if (dp->d_name[1] != '.') { 3973 /* Can't be '..' (nor '.') */ 3974 error = ENOTEMPTY; 3975 goto end; 3976 } 3977 /* FALLTHROUGH */ 3978 case 1: 3979 if (dp->d_name[0] != '.') { 3980 /* Can't be '..' nor '.' */ 3981 error = ENOTEMPTY; 3982 goto end; 3983 } 3984 break; 3985 3986 default: 3987 error = ENOTEMPTY; 3988 goto end; 3989 } 3990 } 3991 3992 end: 3993 free(dirbuf, M_TEMP); 3994 return (error); 3995 } 3996 3997 3998 static u_long vn_lock_pair_pause_cnt; 3999 SYSCTL_ULONG(_debug, OID_AUTO, vn_lock_pair_pause, CTLFLAG_RD, 4000 &vn_lock_pair_pause_cnt, 0, 4001 "Count of vn_lock_pair deadlocks"); 4002 4003 u_int vn_lock_pair_pause_max; 4004 SYSCTL_UINT(_debug, OID_AUTO, vn_lock_pair_pause_max, CTLFLAG_RW, 4005 &vn_lock_pair_pause_max, 0, 4006 "Max ticks for vn_lock_pair deadlock avoidance sleep"); 4007 4008 static void 4009 vn_lock_pair_pause(const char *wmesg) 4010 { 4011 atomic_add_long(&vn_lock_pair_pause_cnt, 1); 4012 pause(wmesg, prng32_bounded(vn_lock_pair_pause_max)); 4013 } 4014 4015 /* 4016 * Lock pair of vnodes vp1, vp2, avoiding lock order reversal. 4017 * vp1_locked indicates whether vp1 is locked; if not, vp1 must be 4018 * unlocked. Same for vp2 and vp2_locked. One of the vnodes can be 4019 * NULL. 4020 * 4021 * The function returns with both vnodes exclusively or shared locked, 4022 * according to corresponding lkflags, and guarantees that it does not 4023 * create lock order reversal with other threads during its execution. 4024 * Both vnodes could be unlocked temporary (and reclaimed). 4025 * 4026 * If requesting shared locking, locked vnode lock must not be recursed. 4027 * 4028 * Only one of LK_SHARED and LK_EXCLUSIVE must be specified. 4029 * LK_NODDLKTREAT can be optionally passed. 4030 */ 4031 void 4032 vn_lock_pair(struct vnode *vp1, bool vp1_locked, int lkflags1, 4033 struct vnode *vp2, bool vp2_locked, int lkflags2) 4034 { 4035 int error; 4036 4037 MPASS(((lkflags1 & LK_SHARED) != 0) ^ ((lkflags1 & LK_EXCLUSIVE) != 0)); 4038 MPASS((lkflags1 & ~(LK_SHARED | LK_EXCLUSIVE | LK_NODDLKTREAT)) == 0); 4039 MPASS(((lkflags2 & LK_SHARED) != 0) ^ ((lkflags2 & LK_EXCLUSIVE) != 0)); 4040 MPASS((lkflags2 & ~(LK_SHARED | LK_EXCLUSIVE | LK_NODDLKTREAT)) == 0); 4041 4042 if (vp1 == NULL && vp2 == NULL) 4043 return; 4044 4045 if (vp1 != NULL) { 4046 if ((lkflags1 & LK_SHARED) != 0 && 4047 (vp1->v_vnlock->lock_object.lo_flags & LK_NOSHARE) != 0) 4048 lkflags1 = (lkflags1 & ~LK_SHARED) | LK_EXCLUSIVE; 4049 if (vp1_locked && VOP_ISLOCKED(vp1) != LK_EXCLUSIVE) { 4050 ASSERT_VOP_LOCKED(vp1, "vp1"); 4051 if ((lkflags1 & LK_EXCLUSIVE) != 0) { 4052 VOP_UNLOCK(vp1); 4053 ASSERT_VOP_UNLOCKED(vp1, 4054 "vp1 shared recursed"); 4055 vp1_locked = false; 4056 } 4057 } else if (!vp1_locked) 4058 ASSERT_VOP_UNLOCKED(vp1, "vp1"); 4059 } else { 4060 vp1_locked = true; 4061 } 4062 4063 if (vp2 != NULL) { 4064 if ((lkflags2 & LK_SHARED) != 0 && 4065 (vp2->v_vnlock->lock_object.lo_flags & LK_NOSHARE) != 0) 4066 lkflags2 = (lkflags2 & ~LK_SHARED) | LK_EXCLUSIVE; 4067 if (vp2_locked && VOP_ISLOCKED(vp2) != LK_EXCLUSIVE) { 4068 ASSERT_VOP_LOCKED(vp2, "vp2"); 4069 if ((lkflags2 & LK_EXCLUSIVE) != 0) { 4070 VOP_UNLOCK(vp2); 4071 ASSERT_VOP_UNLOCKED(vp2, 4072 "vp2 shared recursed"); 4073 vp2_locked = false; 4074 } 4075 } else if (!vp2_locked) 4076 ASSERT_VOP_UNLOCKED(vp2, "vp2"); 4077 } else { 4078 vp2_locked = true; 4079 } 4080 4081 if (!vp1_locked && !vp2_locked) { 4082 vn_lock(vp1, lkflags1 | LK_RETRY); 4083 vp1_locked = true; 4084 } 4085 4086 while (!vp1_locked || !vp2_locked) { 4087 if (vp1_locked && vp2 != NULL) { 4088 if (vp1 != NULL) { 4089 error = VOP_LOCK1(vp2, lkflags2 | LK_NOWAIT, 4090 __FILE__, __LINE__); 4091 if (error == 0) 4092 break; 4093 VOP_UNLOCK(vp1); 4094 vp1_locked = false; 4095 vn_lock_pair_pause("vlp1"); 4096 } 4097 vn_lock(vp2, lkflags2 | LK_RETRY); 4098 vp2_locked = true; 4099 } 4100 if (vp2_locked && vp1 != NULL) { 4101 if (vp2 != NULL) { 4102 error = VOP_LOCK1(vp1, lkflags1 | LK_NOWAIT, 4103 __FILE__, __LINE__); 4104 if (error == 0) 4105 break; 4106 VOP_UNLOCK(vp2); 4107 vp2_locked = false; 4108 vn_lock_pair_pause("vlp2"); 4109 } 4110 vn_lock(vp1, lkflags1 | LK_RETRY); 4111 vp1_locked = true; 4112 } 4113 } 4114 if (vp1 != NULL) { 4115 if (lkflags1 == LK_EXCLUSIVE) 4116 ASSERT_VOP_ELOCKED(vp1, "vp1 ret"); 4117 else 4118 ASSERT_VOP_LOCKED(vp1, "vp1 ret"); 4119 } 4120 if (vp2 != NULL) { 4121 if (lkflags2 == LK_EXCLUSIVE) 4122 ASSERT_VOP_ELOCKED(vp2, "vp2 ret"); 4123 else 4124 ASSERT_VOP_LOCKED(vp2, "vp2 ret"); 4125 } 4126 } 4127 4128 int 4129 vn_lktype_write(struct mount *mp, struct vnode *vp) 4130 { 4131 if (MNT_SHARED_WRITES(mp) || 4132 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) 4133 return (LK_SHARED); 4134 return (LK_EXCLUSIVE); 4135 } 4136