Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_vnops.c
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1 /*- 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org> 11 * Copyright (c) 2013, 2014 The FreeBSD Foundation 12 * 13 * Portions of this software were developed by Konstantin Belousov 14 * under sponsorship from the FreeBSD Foundation. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 1. Redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer. 21 * 2. Redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * @(#)vfs_vnops.c 8.2 (Berkeley) 1/21/94 41 */ 42 43 #include <sys/cdefs.h> 44 __FBSDID("$FreeBSD: releng/11.1/sys/kern/vfs_vnops.c 338606 2018-09-12 05:07:35Z gordon $"); 45 46 #include "opt_hwpmc_hooks.h" 47 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/disk.h> 51 #include <sys/fail.h> 52 #include <sys/fcntl.h> 53 #include <sys/file.h> 54 #include <sys/kdb.h> 55 #include <sys/stat.h> 56 #include <sys/priv.h> 57 #include <sys/proc.h> 58 #include <sys/limits.h> 59 #include <sys/lock.h> 60 #include <sys/mman.h> 61 #include <sys/mount.h> 62 #include <sys/mutex.h> 63 #include <sys/namei.h> 64 #include <sys/vnode.h> 65 #include <sys/bio.h> 66 #include <sys/buf.h> 67 #include <sys/filio.h> 68 #include <sys/resourcevar.h> 69 #include <sys/rwlock.h> 70 #include <sys/sx.h> 71 #include <sys/sysctl.h> 72 #include <sys/ttycom.h> 73 #include <sys/conf.h> 74 #include <sys/syslog.h> 75 #include <sys/unistd.h> 76 #include <sys/user.h> 77 78 #include <security/audit/audit.h> 79 #include <security/mac/mac_framework.h> 80 81 #include <vm/vm.h> 82 #include <vm/vm_extern.h> 83 #include <vm/pmap.h> 84 #include <vm/vm_map.h> 85 #include <vm/vm_object.h> 86 #include <vm/vm_page.h> 87 #include <vm/vnode_pager.h> 88 89 #ifdef HWPMC_HOOKS 90 #include <sys/pmckern.h> 91 #endif 92 93 static fo_rdwr_t vn_read; 94 static fo_rdwr_t vn_write; 95 static fo_rdwr_t vn_io_fault; 96 static fo_truncate_t vn_truncate; 97 static fo_ioctl_t vn_ioctl; 98 static fo_poll_t vn_poll; 99 static fo_kqfilter_t vn_kqfilter; 100 static fo_stat_t vn_statfile; 101 static fo_close_t vn_closefile; 102 static fo_mmap_t vn_mmap; 103 104 struct fileops vnops = { 105 .fo_read = vn_io_fault, 106 .fo_write = vn_io_fault, 107 .fo_truncate = vn_truncate, 108 .fo_ioctl = vn_ioctl, 109 .fo_poll = vn_poll, 110 .fo_kqfilter = vn_kqfilter, 111 .fo_stat = vn_statfile, 112 .fo_close = vn_closefile, 113 .fo_chmod = vn_chmod, 114 .fo_chown = vn_chown, 115 .fo_sendfile = vn_sendfile, 116 .fo_seek = vn_seek, 117 .fo_fill_kinfo = vn_fill_kinfo, 118 .fo_mmap = vn_mmap, 119 .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE 120 }; 121 122 static const int io_hold_cnt = 16; 123 static int vn_io_fault_enable = 1; 124 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RW, 125 &vn_io_fault_enable, 0, "Enable vn_io_fault lock avoidance"); 126 static int vn_io_fault_prefault = 0; 127 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_prefault, CTLFLAG_RW, 128 &vn_io_fault_prefault, 0, "Enable vn_io_fault prefaulting"); 129 static u_long vn_io_faults_cnt; 130 SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD, 131 &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers"); 132 133 /* 134 * Returns true if vn_io_fault mode of handling the i/o request should 135 * be used. 136 */ 137 static bool 138 do_vn_io_fault(struct vnode *vp, struct uio *uio) 139 { 140 struct mount *mp; 141 142 return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG && 143 (mp = vp->v_mount) != NULL && 144 (mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable); 145 } 146 147 /* 148 * Structure used to pass arguments to vn_io_fault1(), to do either 149 * file- or vnode-based I/O calls. 150 */ 151 struct vn_io_fault_args { 152 enum { 153 VN_IO_FAULT_FOP, 154 VN_IO_FAULT_VOP 155 } kind; 156 struct ucred *cred; 157 int flags; 158 union { 159 struct fop_args_tag { 160 struct file *fp; 161 fo_rdwr_t *doio; 162 } fop_args; 163 struct vop_args_tag { 164 struct vnode *vp; 165 } vop_args; 166 } args; 167 }; 168 169 static int vn_io_fault1(struct vnode *vp, struct uio *uio, 170 struct vn_io_fault_args *args, struct thread *td); 171 172 int 173 vn_open(ndp, flagp, cmode, fp) 174 struct nameidata *ndp; 175 int *flagp, cmode; 176 struct file *fp; 177 { 178 struct thread *td = ndp->ni_cnd.cn_thread; 179 180 return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp)); 181 } 182 183 /* 184 * Common code for vnode open operations via a name lookup. 185 * Lookup the vnode and invoke VOP_CREATE if needed. 186 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 187 * 188 * Note that this does NOT free nameidata for the successful case, 189 * due to the NDINIT being done elsewhere. 190 */ 191 int 192 vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags, 193 struct ucred *cred, struct file *fp) 194 { 195 struct vnode *vp; 196 struct mount *mp; 197 struct thread *td = ndp->ni_cnd.cn_thread; 198 struct vattr vat; 199 struct vattr *vap = &vat; 200 int fmode, error; 201 202 restart: 203 fmode = *flagp; 204 if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT | 205 O_EXCL | O_DIRECTORY)) 206 return (EINVAL); 207 else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) { 208 ndp->ni_cnd.cn_nameiop = CREATE; 209 /* 210 * Set NOCACHE to avoid flushing the cache when 211 * rolling in many files at once. 212 */ 213 ndp->ni_cnd.cn_flags = ISOPEN | LOCKPARENT | LOCKLEAF | NOCACHE; 214 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 215 ndp->ni_cnd.cn_flags |= FOLLOW; 216 if (!(vn_open_flags & VN_OPEN_NOAUDIT)) 217 ndp->ni_cnd.cn_flags |= AUDITVNODE1; 218 if (vn_open_flags & VN_OPEN_NOCAPCHECK) 219 ndp->ni_cnd.cn_flags |= NOCAPCHECK; 220 bwillwrite(); 221 if ((error = namei(ndp)) != 0) 222 return (error); 223 if (ndp->ni_vp == NULL) { 224 VATTR_NULL(vap); 225 vap->va_type = VREG; 226 vap->va_mode = cmode; 227 if (fmode & O_EXCL) 228 vap->va_vaflags |= VA_EXCLUSIVE; 229 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) { 230 NDFREE(ndp, NDF_ONLY_PNBUF); 231 vput(ndp->ni_dvp); 232 if ((error = vn_start_write(NULL, &mp, 233 V_XSLEEP | PCATCH)) != 0) 234 return (error); 235 goto restart; 236 } 237 if ((vn_open_flags & VN_OPEN_NAMECACHE) != 0) 238 ndp->ni_cnd.cn_flags |= MAKEENTRY; 239 #ifdef MAC 240 error = mac_vnode_check_create(cred, ndp->ni_dvp, 241 &ndp->ni_cnd, vap); 242 if (error == 0) 243 #endif 244 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 245 &ndp->ni_cnd, vap); 246 vput(ndp->ni_dvp); 247 vn_finished_write(mp); 248 if (error) { 249 NDFREE(ndp, NDF_ONLY_PNBUF); 250 return (error); 251 } 252 fmode &= ~O_TRUNC; 253 vp = ndp->ni_vp; 254 } else { 255 if (ndp->ni_dvp == ndp->ni_vp) 256 vrele(ndp->ni_dvp); 257 else 258 vput(ndp->ni_dvp); 259 ndp->ni_dvp = NULL; 260 vp = ndp->ni_vp; 261 if (fmode & O_EXCL) { 262 error = EEXIST; 263 goto bad; 264 } 265 fmode &= ~O_CREAT; 266 } 267 } else { 268 ndp->ni_cnd.cn_nameiop = LOOKUP; 269 ndp->ni_cnd.cn_flags = ISOPEN | 270 ((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF; 271 if (!(fmode & FWRITE)) 272 ndp->ni_cnd.cn_flags |= LOCKSHARED; 273 if (!(vn_open_flags & VN_OPEN_NOAUDIT)) 274 ndp->ni_cnd.cn_flags |= AUDITVNODE1; 275 if (vn_open_flags & VN_OPEN_NOCAPCHECK) 276 ndp->ni_cnd.cn_flags |= NOCAPCHECK; 277 if ((error = namei(ndp)) != 0) 278 return (error); 279 vp = ndp->ni_vp; 280 } 281 error = vn_open_vnode(vp, fmode, cred, td, fp); 282 if (error) 283 goto bad; 284 *flagp = fmode; 285 return (0); 286 bad: 287 NDFREE(ndp, NDF_ONLY_PNBUF); 288 vput(vp); 289 *flagp = fmode; 290 ndp->ni_vp = NULL; 291 return (error); 292 } 293 294 /* 295 * Common code for vnode open operations once a vnode is located. 296 * Check permissions, and call the VOP_OPEN routine. 297 */ 298 int 299 vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred, 300 struct thread *td, struct file *fp) 301 { 302 accmode_t accmode; 303 struct flock lf; 304 int error, lock_flags, type; 305 306 if (vp->v_type == VLNK) 307 return (EMLINK); 308 if (vp->v_type == VSOCK) 309 return (EOPNOTSUPP); 310 if (vp->v_type != VDIR && fmode & O_DIRECTORY) 311 return (ENOTDIR); 312 accmode = 0; 313 if (fmode & (FWRITE | O_TRUNC)) { 314 if (vp->v_type == VDIR) 315 return (EISDIR); 316 accmode |= VWRITE; 317 } 318 if (fmode & FREAD) 319 accmode |= VREAD; 320 if (fmode & FEXEC) 321 accmode |= VEXEC; 322 if ((fmode & O_APPEND) && (fmode & FWRITE)) 323 accmode |= VAPPEND; 324 #ifdef MAC 325 if (fmode & O_CREAT) 326 accmode |= VCREAT; 327 if (fmode & O_VERIFY) 328 accmode |= VVERIFY; 329 error = mac_vnode_check_open(cred, vp, accmode); 330 if (error) 331 return (error); 332 333 accmode &= ~(VCREAT | VVERIFY); 334 #endif 335 if ((fmode & O_CREAT) == 0) { 336 if (accmode & VWRITE) { 337 error = vn_writechk(vp); 338 if (error) 339 return (error); 340 } 341 if (accmode) { 342 error = VOP_ACCESS(vp, accmode, cred, td); 343 if (error) 344 return (error); 345 } 346 } 347 if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 348 vn_lock(vp, LK_UPGRADE | LK_RETRY); 349 if ((error = VOP_OPEN(vp, fmode, cred, td, fp)) != 0) 350 return (error); 351 352 while ((fmode & (O_EXLOCK | O_SHLOCK)) != 0) { 353 KASSERT(fp != NULL, ("open with flock requires fp")); 354 if (fp->f_type != DTYPE_NONE && fp->f_type != DTYPE_VNODE) { 355 error = EOPNOTSUPP; 356 break; 357 } 358 lock_flags = VOP_ISLOCKED(vp); 359 VOP_UNLOCK(vp, 0); 360 lf.l_whence = SEEK_SET; 361 lf.l_start = 0; 362 lf.l_len = 0; 363 if (fmode & O_EXLOCK) 364 lf.l_type = F_WRLCK; 365 else 366 lf.l_type = F_RDLCK; 367 type = F_FLOCK; 368 if ((fmode & FNONBLOCK) == 0) 369 type |= F_WAIT; 370 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type); 371 if (error == 0) 372 fp->f_flag |= FHASLOCK; 373 vn_lock(vp, lock_flags | LK_RETRY); 374 if (error != 0) 375 break; 376 if ((vp->v_iflag & VI_DOOMED) != 0) { 377 error = ENOENT; 378 break; 379 } 380 381 /* 382 * Another thread might have used this vnode as an 383 * executable while the vnode lock was dropped. 384 * Ensure the vnode is still able to be opened for 385 * writing after the lock has been obtained. 386 */ 387 if ((accmode & VWRITE) != 0) 388 error = vn_writechk(vp); 389 break; 390 } 391 392 if (error != 0) { 393 fp->f_flag |= FOPENFAILED; 394 fp->f_vnode = vp; 395 if (fp->f_ops == &badfileops) { 396 fp->f_type = DTYPE_VNODE; 397 fp->f_ops = &vnops; 398 } 399 vref(vp); 400 } else if ((fmode & FWRITE) != 0) { 401 VOP_ADD_WRITECOUNT(vp, 1); 402 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 403 __func__, vp, vp->v_writecount); 404 } 405 ASSERT_VOP_LOCKED(vp, "vn_open_vnode"); 406 return (error); 407 } 408 409 /* 410 * Check for write permissions on the specified vnode. 411 * Prototype text segments cannot be written. 412 */ 413 int 414 vn_writechk(vp) 415 register struct vnode *vp; 416 { 417 418 ASSERT_VOP_LOCKED(vp, "vn_writechk"); 419 /* 420 * If there's shared text associated with 421 * the vnode, try to free it up once. If 422 * we fail, we can't allow writing. 423 */ 424 if (VOP_IS_TEXT(vp)) 425 return (ETXTBSY); 426 427 return (0); 428 } 429 430 /* 431 * Vnode close call 432 */ 433 static int 434 vn_close1(struct vnode *vp, int flags, struct ucred *file_cred, 435 struct thread *td, bool keep_ref) 436 { 437 struct mount *mp; 438 int error, lock_flags; 439 440 if (vp->v_type != VFIFO && (flags & FWRITE) == 0 && 441 MNT_EXTENDED_SHARED(vp->v_mount)) 442 lock_flags = LK_SHARED; 443 else 444 lock_flags = LK_EXCLUSIVE; 445 446 vn_start_write(vp, &mp, V_WAIT); 447 vn_lock(vp, lock_flags | LK_RETRY); 448 AUDIT_ARG_VNODE1(vp); 449 if ((flags & (FWRITE | FOPENFAILED)) == FWRITE) { 450 VNASSERT(vp->v_writecount > 0, vp, 451 ("vn_close: negative writecount")); 452 VOP_ADD_WRITECOUNT(vp, -1); 453 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 454 __func__, vp, vp->v_writecount); 455 } 456 error = VOP_CLOSE(vp, flags, file_cred, td); 457 if (keep_ref) 458 VOP_UNLOCK(vp, 0); 459 else 460 vput(vp); 461 vn_finished_write(mp); 462 return (error); 463 } 464 465 int 466 vn_close(struct vnode *vp, int flags, struct ucred *file_cred, 467 struct thread *td) 468 { 469 470 return (vn_close1(vp, flags, file_cred, td, false)); 471 } 472 473 /* 474 * Heuristic to detect sequential operation. 475 */ 476 static int 477 sequential_heuristic(struct uio *uio, struct file *fp) 478 { 479 480 ASSERT_VOP_LOCKED(fp->f_vnode, __func__); 481 if (fp->f_flag & FRDAHEAD) 482 return (fp->f_seqcount << IO_SEQSHIFT); 483 484 /* 485 * Offset 0 is handled specially. open() sets f_seqcount to 1 so 486 * that the first I/O is normally considered to be slightly 487 * sequential. Seeking to offset 0 doesn't change sequentiality 488 * unless previous seeks have reduced f_seqcount to 0, in which 489 * case offset 0 is not special. 490 */ 491 if ((uio->uio_offset == 0 && fp->f_seqcount > 0) || 492 uio->uio_offset == fp->f_nextoff) { 493 /* 494 * f_seqcount is in units of fixed-size blocks so that it 495 * depends mainly on the amount of sequential I/O and not 496 * much on the number of sequential I/O's. The fixed size 497 * of 16384 is hard-coded here since it is (not quite) just 498 * a magic size that works well here. This size is more 499 * closely related to the best I/O size for real disks than 500 * to any block size used by software. 501 */ 502 fp->f_seqcount += howmany(uio->uio_resid, 16384); 503 if (fp->f_seqcount > IO_SEQMAX) 504 fp->f_seqcount = IO_SEQMAX; 505 return (fp->f_seqcount << IO_SEQSHIFT); 506 } 507 508 /* Not sequential. Quickly draw-down sequentiality. */ 509 if (fp->f_seqcount > 1) 510 fp->f_seqcount = 1; 511 else 512 fp->f_seqcount = 0; 513 return (0); 514 } 515 516 /* 517 * Package up an I/O request on a vnode into a uio and do it. 518 */ 519 int 520 vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset, 521 enum uio_seg segflg, int ioflg, struct ucred *active_cred, 522 struct ucred *file_cred, ssize_t *aresid, struct thread *td) 523 { 524 struct uio auio; 525 struct iovec aiov; 526 struct mount *mp; 527 struct ucred *cred; 528 void *rl_cookie; 529 struct vn_io_fault_args args; 530 int error, lock_flags; 531 532 if (offset < 0 && vp->v_type != VCHR) 533 return (EINVAL); 534 auio.uio_iov = &aiov; 535 auio.uio_iovcnt = 1; 536 aiov.iov_base = base; 537 aiov.iov_len = len; 538 auio.uio_resid = len; 539 auio.uio_offset = offset; 540 auio.uio_segflg = segflg; 541 auio.uio_rw = rw; 542 auio.uio_td = td; 543 error = 0; 544 545 if ((ioflg & IO_NODELOCKED) == 0) { 546 if ((ioflg & IO_RANGELOCKED) == 0) { 547 if (rw == UIO_READ) { 548 rl_cookie = vn_rangelock_rlock(vp, offset, 549 offset + len); 550 } else { 551 rl_cookie = vn_rangelock_wlock(vp, offset, 552 offset + len); 553 } 554 } else 555 rl_cookie = NULL; 556 mp = NULL; 557 if (rw == UIO_WRITE) { 558 if (vp->v_type != VCHR && 559 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) 560 != 0) 561 goto out; 562 if (MNT_SHARED_WRITES(mp) || 563 ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount))) 564 lock_flags = LK_SHARED; 565 else 566 lock_flags = LK_EXCLUSIVE; 567 } else 568 lock_flags = LK_SHARED; 569 vn_lock(vp, lock_flags | LK_RETRY); 570 } else 571 rl_cookie = NULL; 572 573 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 574 #ifdef MAC 575 if ((ioflg & IO_NOMACCHECK) == 0) { 576 if (rw == UIO_READ) 577 error = mac_vnode_check_read(active_cred, file_cred, 578 vp); 579 else 580 error = mac_vnode_check_write(active_cred, file_cred, 581 vp); 582 } 583 #endif 584 if (error == 0) { 585 if (file_cred != NULL) 586 cred = file_cred; 587 else 588 cred = active_cred; 589 if (do_vn_io_fault(vp, &auio)) { 590 args.kind = VN_IO_FAULT_VOP; 591 args.cred = cred; 592 args.flags = ioflg; 593 args.args.vop_args.vp = vp; 594 error = vn_io_fault1(vp, &auio, &args, td); 595 } else if (rw == UIO_READ) { 596 error = VOP_READ(vp, &auio, ioflg, cred); 597 } else /* if (rw == UIO_WRITE) */ { 598 error = VOP_WRITE(vp, &auio, ioflg, cred); 599 } 600 } 601 if (aresid) 602 *aresid = auio.uio_resid; 603 else 604 if (auio.uio_resid && error == 0) 605 error = EIO; 606 if ((ioflg & IO_NODELOCKED) == 0) { 607 VOP_UNLOCK(vp, 0); 608 if (mp != NULL) 609 vn_finished_write(mp); 610 } 611 out: 612 if (rl_cookie != NULL) 613 vn_rangelock_unlock(vp, rl_cookie); 614 return (error); 615 } 616 617 /* 618 * Package up an I/O request on a vnode into a uio and do it. The I/O 619 * request is split up into smaller chunks and we try to avoid saturating 620 * the buffer cache while potentially holding a vnode locked, so we 621 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield() 622 * to give other processes a chance to lock the vnode (either other processes 623 * core'ing the same binary, or unrelated processes scanning the directory). 624 */ 625 int 626 vn_rdwr_inchunks(rw, vp, base, len, offset, segflg, ioflg, active_cred, 627 file_cred, aresid, td) 628 enum uio_rw rw; 629 struct vnode *vp; 630 void *base; 631 size_t len; 632 off_t offset; 633 enum uio_seg segflg; 634 int ioflg; 635 struct ucred *active_cred; 636 struct ucred *file_cred; 637 size_t *aresid; 638 struct thread *td; 639 { 640 int error = 0; 641 ssize_t iaresid; 642 643 do { 644 int chunk; 645 646 /* 647 * Force `offset' to a multiple of MAXBSIZE except possibly 648 * for the first chunk, so that filesystems only need to 649 * write full blocks except possibly for the first and last 650 * chunks. 651 */ 652 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE; 653 654 if (chunk > len) 655 chunk = len; 656 if (rw != UIO_READ && vp->v_type == VREG) 657 bwillwrite(); 658 iaresid = 0; 659 error = vn_rdwr(rw, vp, base, chunk, offset, segflg, 660 ioflg, active_cred, file_cred, &iaresid, td); 661 len -= chunk; /* aresid calc already includes length */ 662 if (error) 663 break; 664 offset += chunk; 665 base = (char *)base + chunk; 666 kern_yield(PRI_USER); 667 } while (len); 668 if (aresid) 669 *aresid = len + iaresid; 670 return (error); 671 } 672 673 off_t 674 foffset_lock(struct file *fp, int flags) 675 { 676 struct mtx *mtxp; 677 off_t res; 678 679 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 680 681 #if OFF_MAX <= LONG_MAX 682 /* 683 * Caller only wants the current f_offset value. Assume that 684 * the long and shorter integer types reads are atomic. 685 */ 686 if ((flags & FOF_NOLOCK) != 0) 687 return (fp->f_offset); 688 #endif 689 690 /* 691 * According to McKusick the vn lock was protecting f_offset here. 692 * It is now protected by the FOFFSET_LOCKED flag. 693 */ 694 mtxp = mtx_pool_find(mtxpool_sleep, fp); 695 mtx_lock(mtxp); 696 if ((flags & FOF_NOLOCK) == 0) { 697 while (fp->f_vnread_flags & FOFFSET_LOCKED) { 698 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING; 699 msleep(&fp->f_vnread_flags, mtxp, PUSER -1, 700 "vofflock", 0); 701 } 702 fp->f_vnread_flags |= FOFFSET_LOCKED; 703 } 704 res = fp->f_offset; 705 mtx_unlock(mtxp); 706 return (res); 707 } 708 709 void 710 foffset_unlock(struct file *fp, off_t val, int flags) 711 { 712 struct mtx *mtxp; 713 714 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 715 716 #if OFF_MAX <= LONG_MAX 717 if ((flags & FOF_NOLOCK) != 0) { 718 if ((flags & FOF_NOUPDATE) == 0) 719 fp->f_offset = val; 720 if ((flags & FOF_NEXTOFF) != 0) 721 fp->f_nextoff = val; 722 return; 723 } 724 #endif 725 726 mtxp = mtx_pool_find(mtxpool_sleep, fp); 727 mtx_lock(mtxp); 728 if ((flags & FOF_NOUPDATE) == 0) 729 fp->f_offset = val; 730 if ((flags & FOF_NEXTOFF) != 0) 731 fp->f_nextoff = val; 732 if ((flags & FOF_NOLOCK) == 0) { 733 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0, 734 ("Lost FOFFSET_LOCKED")); 735 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING) 736 wakeup(&fp->f_vnread_flags); 737 fp->f_vnread_flags = 0; 738 } 739 mtx_unlock(mtxp); 740 } 741 742 void 743 foffset_lock_uio(struct file *fp, struct uio *uio, int flags) 744 { 745 746 if ((flags & FOF_OFFSET) == 0) 747 uio->uio_offset = foffset_lock(fp, flags); 748 } 749 750 void 751 foffset_unlock_uio(struct file *fp, struct uio *uio, int flags) 752 { 753 754 if ((flags & FOF_OFFSET) == 0) 755 foffset_unlock(fp, uio->uio_offset, flags); 756 } 757 758 static int 759 get_advice(struct file *fp, struct uio *uio) 760 { 761 struct mtx *mtxp; 762 int ret; 763 764 ret = POSIX_FADV_NORMAL; 765 if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG) 766 return (ret); 767 768 mtxp = mtx_pool_find(mtxpool_sleep, fp); 769 mtx_lock(mtxp); 770 if (fp->f_advice != NULL && 771 uio->uio_offset >= fp->f_advice->fa_start && 772 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end) 773 ret = fp->f_advice->fa_advice; 774 mtx_unlock(mtxp); 775 return (ret); 776 } 777 778 /* 779 * File table vnode read routine. 780 */ 781 static int 782 vn_read(fp, uio, active_cred, flags, td) 783 struct file *fp; 784 struct uio *uio; 785 struct ucred *active_cred; 786 int flags; 787 struct thread *td; 788 { 789 struct vnode *vp; 790 off_t orig_offset; 791 int error, ioflag; 792 int advice; 793 794 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 795 uio->uio_td, td)); 796 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 797 vp = fp->f_vnode; 798 ioflag = 0; 799 if (fp->f_flag & FNONBLOCK) 800 ioflag |= IO_NDELAY; 801 if (fp->f_flag & O_DIRECT) 802 ioflag |= IO_DIRECT; 803 advice = get_advice(fp, uio); 804 vn_lock(vp, LK_SHARED | LK_RETRY); 805 806 switch (advice) { 807 case POSIX_FADV_NORMAL: 808 case POSIX_FADV_SEQUENTIAL: 809 case POSIX_FADV_NOREUSE: 810 ioflag |= sequential_heuristic(uio, fp); 811 break; 812 case POSIX_FADV_RANDOM: 813 /* Disable read-ahead for random I/O. */ 814 break; 815 } 816 orig_offset = uio->uio_offset; 817 818 #ifdef MAC 819 error = mac_vnode_check_read(active_cred, fp->f_cred, vp); 820 if (error == 0) 821 #endif 822 error = VOP_READ(vp, uio, ioflag, fp->f_cred); 823 fp->f_nextoff = uio->uio_offset; 824 VOP_UNLOCK(vp, 0); 825 if (error == 0 && advice == POSIX_FADV_NOREUSE && 826 orig_offset != uio->uio_offset) 827 /* 828 * Use POSIX_FADV_DONTNEED to flush pages and buffers 829 * for the backing file after a POSIX_FADV_NOREUSE 830 * read(2). 831 */ 832 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 833 POSIX_FADV_DONTNEED); 834 return (error); 835 } 836 837 /* 838 * File table vnode write routine. 839 */ 840 static int 841 vn_write(fp, uio, active_cred, flags, td) 842 struct file *fp; 843 struct uio *uio; 844 struct ucred *active_cred; 845 int flags; 846 struct thread *td; 847 { 848 struct vnode *vp; 849 struct mount *mp; 850 off_t orig_offset; 851 int error, ioflag, lock_flags; 852 int advice; 853 854 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 855 uio->uio_td, td)); 856 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 857 vp = fp->f_vnode; 858 if (vp->v_type == VREG) 859 bwillwrite(); 860 ioflag = IO_UNIT; 861 if (vp->v_type == VREG && (fp->f_flag & O_APPEND)) 862 ioflag |= IO_APPEND; 863 if (fp->f_flag & FNONBLOCK) 864 ioflag |= IO_NDELAY; 865 if (fp->f_flag & O_DIRECT) 866 ioflag |= IO_DIRECT; 867 if ((fp->f_flag & O_FSYNC) || 868 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) 869 ioflag |= IO_SYNC; 870 mp = NULL; 871 if (vp->v_type != VCHR && 872 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0) 873 goto unlock; 874 875 advice = get_advice(fp, uio); 876 877 if (MNT_SHARED_WRITES(mp) || 878 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) { 879 lock_flags = LK_SHARED; 880 } else { 881 lock_flags = LK_EXCLUSIVE; 882 } 883 884 vn_lock(vp, lock_flags | LK_RETRY); 885 switch (advice) { 886 case POSIX_FADV_NORMAL: 887 case POSIX_FADV_SEQUENTIAL: 888 case POSIX_FADV_NOREUSE: 889 ioflag |= sequential_heuristic(uio, fp); 890 break; 891 case POSIX_FADV_RANDOM: 892 /* XXX: Is this correct? */ 893 break; 894 } 895 orig_offset = uio->uio_offset; 896 897 #ifdef MAC 898 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 899 if (error == 0) 900 #endif 901 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred); 902 fp->f_nextoff = uio->uio_offset; 903 VOP_UNLOCK(vp, 0); 904 if (vp->v_type != VCHR) 905 vn_finished_write(mp); 906 if (error == 0 && advice == POSIX_FADV_NOREUSE && 907 orig_offset != uio->uio_offset) 908 /* 909 * Use POSIX_FADV_DONTNEED to flush pages and buffers 910 * for the backing file after a POSIX_FADV_NOREUSE 911 * write(2). 912 */ 913 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 914 POSIX_FADV_DONTNEED); 915 unlock: 916 return (error); 917 } 918 919 /* 920 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to 921 * prevent the following deadlock: 922 * 923 * Assume that the thread A reads from the vnode vp1 into userspace 924 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is 925 * currently not resident, then system ends up with the call chain 926 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] -> 927 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2) 928 * which establishes lock order vp1->vn_lock, then vp2->vn_lock. 929 * If, at the same time, thread B reads from vnode vp2 into buffer buf2 930 * backed by the pages of vnode vp1, and some page in buf2 is not 931 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock. 932 * 933 * To prevent the lock order reversal and deadlock, vn_io_fault() does 934 * not allow page faults to happen during VOP_READ() or VOP_WRITE(). 935 * Instead, it first tries to do the whole range i/o with pagefaults 936 * disabled. If all pages in the i/o buffer are resident and mapped, 937 * VOP will succeed (ignoring the genuine filesystem errors). 938 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do 939 * i/o in chunks, with all pages in the chunk prefaulted and held 940 * using vm_fault_quick_hold_pages(). 941 * 942 * Filesystems using this deadlock avoidance scheme should use the 943 * array of the held pages from uio, saved in the curthread->td_ma, 944 * instead of doing uiomove(). A helper function 945 * vn_io_fault_uiomove() converts uiomove request into 946 * uiomove_fromphys() over td_ma array. 947 * 948 * Since vnode locks do not cover the whole i/o anymore, rangelocks 949 * make the current i/o request atomic with respect to other i/os and 950 * truncations. 951 */ 952 953 /* 954 * Decode vn_io_fault_args and perform the corresponding i/o. 955 */ 956 static int 957 vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio, 958 struct thread *td) 959 { 960 961 switch (args->kind) { 962 case VN_IO_FAULT_FOP: 963 return ((args->args.fop_args.doio)(args->args.fop_args.fp, 964 uio, args->cred, args->flags, td)); 965 case VN_IO_FAULT_VOP: 966 if (uio->uio_rw == UIO_READ) { 967 return (VOP_READ(args->args.vop_args.vp, uio, 968 args->flags, args->cred)); 969 } else if (uio->uio_rw == UIO_WRITE) { 970 return (VOP_WRITE(args->args.vop_args.vp, uio, 971 args->flags, args->cred)); 972 } 973 break; 974 } 975 panic("vn_io_fault_doio: unknown kind of io %d %d", args->kind, 976 uio->uio_rw); 977 } 978 979 static int 980 vn_io_fault_touch(char *base, const struct uio *uio) 981 { 982 int r; 983 984 r = fubyte(base); 985 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1)) 986 return (EFAULT); 987 return (0); 988 } 989 990 static int 991 vn_io_fault_prefault_user(const struct uio *uio) 992 { 993 char *base; 994 const struct iovec *iov; 995 size_t len; 996 ssize_t resid; 997 int error, i; 998 999 KASSERT(uio->uio_segflg == UIO_USERSPACE, 1000 ("vn_io_fault_prefault userspace")); 1001 1002 error = i = 0; 1003 iov = uio->uio_iov; 1004 resid = uio->uio_resid; 1005 base = iov->iov_base; 1006 len = iov->iov_len; 1007 while (resid > 0) { 1008 error = vn_io_fault_touch(base, uio); 1009 if (error != 0) 1010 break; 1011 if (len < PAGE_SIZE) { 1012 if (len != 0) { 1013 error = vn_io_fault_touch(base + len - 1, uio); 1014 if (error != 0) 1015 break; 1016 resid -= len; 1017 } 1018 if (++i >= uio->uio_iovcnt) 1019 break; 1020 iov = uio->uio_iov + i; 1021 base = iov->iov_base; 1022 len = iov->iov_len; 1023 } else { 1024 len -= PAGE_SIZE; 1025 base += PAGE_SIZE; 1026 resid -= PAGE_SIZE; 1027 } 1028 } 1029 return (error); 1030 } 1031 1032 /* 1033 * Common code for vn_io_fault(), agnostic to the kind of i/o request. 1034 * Uses vn_io_fault_doio() to make the call to an actual i/o function. 1035 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request 1036 * into args and call vn_io_fault1() to handle faults during the user 1037 * mode buffer accesses. 1038 */ 1039 static int 1040 vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args, 1041 struct thread *td) 1042 { 1043 vm_page_t ma[io_hold_cnt + 2]; 1044 struct uio *uio_clone, short_uio; 1045 struct iovec short_iovec[1]; 1046 vm_page_t *prev_td_ma; 1047 vm_prot_t prot; 1048 vm_offset_t addr, end; 1049 size_t len, resid; 1050 ssize_t adv; 1051 int error, cnt, save, saveheld, prev_td_ma_cnt; 1052 1053 if (vn_io_fault_prefault) { 1054 error = vn_io_fault_prefault_user(uio); 1055 if (error != 0) 1056 return (error); /* Or ignore ? */ 1057 } 1058 1059 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ; 1060 1061 /* 1062 * The UFS follows IO_UNIT directive and replays back both 1063 * uio_offset and uio_resid if an error is encountered during the 1064 * operation. But, since the iovec may be already advanced, 1065 * uio is still in an inconsistent state. 1066 * 1067 * Cache a copy of the original uio, which is advanced to the redo 1068 * point using UIO_NOCOPY below. 1069 */ 1070 uio_clone = cloneuio(uio); 1071 resid = uio->uio_resid; 1072 1073 short_uio.uio_segflg = UIO_USERSPACE; 1074 short_uio.uio_rw = uio->uio_rw; 1075 short_uio.uio_td = uio->uio_td; 1076 1077 save = vm_fault_disable_pagefaults(); 1078 error = vn_io_fault_doio(args, uio, td); 1079 if (error != EFAULT) 1080 goto out; 1081 1082 atomic_add_long(&vn_io_faults_cnt, 1); 1083 uio_clone->uio_segflg = UIO_NOCOPY; 1084 uiomove(NULL, resid - uio->uio_resid, uio_clone); 1085 uio_clone->uio_segflg = uio->uio_segflg; 1086 1087 saveheld = curthread_pflags_set(TDP_UIOHELD); 1088 prev_td_ma = td->td_ma; 1089 prev_td_ma_cnt = td->td_ma_cnt; 1090 1091 while (uio_clone->uio_resid != 0) { 1092 len = uio_clone->uio_iov->iov_len; 1093 if (len == 0) { 1094 KASSERT(uio_clone->uio_iovcnt >= 1, 1095 ("iovcnt underflow")); 1096 uio_clone->uio_iov++; 1097 uio_clone->uio_iovcnt--; 1098 continue; 1099 } 1100 if (len > io_hold_cnt * PAGE_SIZE) 1101 len = io_hold_cnt * PAGE_SIZE; 1102 addr = (uintptr_t)uio_clone->uio_iov->iov_base; 1103 end = round_page(addr + len); 1104 if (end < addr) { 1105 error = EFAULT; 1106 break; 1107 } 1108 cnt = atop(end - trunc_page(addr)); 1109 /* 1110 * A perfectly misaligned address and length could cause 1111 * both the start and the end of the chunk to use partial 1112 * page. +2 accounts for such a situation. 1113 */ 1114 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map, 1115 addr, len, prot, ma, io_hold_cnt + 2); 1116 if (cnt == -1) { 1117 error = EFAULT; 1118 break; 1119 } 1120 short_uio.uio_iov = &short_iovec[0]; 1121 short_iovec[0].iov_base = (void *)addr; 1122 short_uio.uio_iovcnt = 1; 1123 short_uio.uio_resid = short_iovec[0].iov_len = len; 1124 short_uio.uio_offset = uio_clone->uio_offset; 1125 td->td_ma = ma; 1126 td->td_ma_cnt = cnt; 1127 1128 error = vn_io_fault_doio(args, &short_uio, td); 1129 vm_page_unhold_pages(ma, cnt); 1130 adv = len - short_uio.uio_resid; 1131 1132 uio_clone->uio_iov->iov_base = 1133 (char *)uio_clone->uio_iov->iov_base + adv; 1134 uio_clone->uio_iov->iov_len -= adv; 1135 uio_clone->uio_resid -= adv; 1136 uio_clone->uio_offset += adv; 1137 1138 uio->uio_resid -= adv; 1139 uio->uio_offset += adv; 1140 1141 if (error != 0 || adv == 0) 1142 break; 1143 } 1144 td->td_ma = prev_td_ma; 1145 td->td_ma_cnt = prev_td_ma_cnt; 1146 curthread_pflags_restore(saveheld); 1147 out: 1148 vm_fault_enable_pagefaults(save); 1149 free(uio_clone, M_IOV); 1150 return (error); 1151 } 1152 1153 static int 1154 vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred, 1155 int flags, struct thread *td) 1156 { 1157 fo_rdwr_t *doio; 1158 struct vnode *vp; 1159 void *rl_cookie; 1160 struct vn_io_fault_args args; 1161 int error; 1162 1163 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write; 1164 vp = fp->f_vnode; 1165 foffset_lock_uio(fp, uio, flags); 1166 if (do_vn_io_fault(vp, uio)) { 1167 args.kind = VN_IO_FAULT_FOP; 1168 args.args.fop_args.fp = fp; 1169 args.args.fop_args.doio = doio; 1170 args.cred = active_cred; 1171 args.flags = flags | FOF_OFFSET; 1172 if (uio->uio_rw == UIO_READ) { 1173 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset, 1174 uio->uio_offset + uio->uio_resid); 1175 } else if ((fp->f_flag & O_APPEND) != 0 || 1176 (flags & FOF_OFFSET) == 0) { 1177 /* For appenders, punt and lock the whole range. */ 1178 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1179 } else { 1180 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset, 1181 uio->uio_offset + uio->uio_resid); 1182 } 1183 error = vn_io_fault1(vp, uio, &args, td); 1184 vn_rangelock_unlock(vp, rl_cookie); 1185 } else { 1186 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td); 1187 } 1188 foffset_unlock_uio(fp, uio, flags); 1189 return (error); 1190 } 1191 1192 /* 1193 * Helper function to perform the requested uiomove operation using 1194 * the held pages for io->uio_iov[0].iov_base buffer instead of 1195 * copyin/copyout. Access to the pages with uiomove_fromphys() 1196 * instead of iov_base prevents page faults that could occur due to 1197 * pmap_collect() invalidating the mapping created by 1198 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or 1199 * object cleanup revoking the write access from page mappings. 1200 * 1201 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove() 1202 * instead of plain uiomove(). 1203 */ 1204 int 1205 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio) 1206 { 1207 struct uio transp_uio; 1208 struct iovec transp_iov[1]; 1209 struct thread *td; 1210 size_t adv; 1211 int error, pgadv; 1212 1213 td = curthread; 1214 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1215 uio->uio_segflg != UIO_USERSPACE) 1216 return (uiomove(data, xfersize, uio)); 1217 1218 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1219 transp_iov[0].iov_base = data; 1220 transp_uio.uio_iov = &transp_iov[0]; 1221 transp_uio.uio_iovcnt = 1; 1222 if (xfersize > uio->uio_resid) 1223 xfersize = uio->uio_resid; 1224 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize; 1225 transp_uio.uio_offset = 0; 1226 transp_uio.uio_segflg = UIO_SYSSPACE; 1227 /* 1228 * Since transp_iov points to data, and td_ma page array 1229 * corresponds to original uio->uio_iov, we need to invert the 1230 * direction of the i/o operation as passed to 1231 * uiomove_fromphys(). 1232 */ 1233 switch (uio->uio_rw) { 1234 case UIO_WRITE: 1235 transp_uio.uio_rw = UIO_READ; 1236 break; 1237 case UIO_READ: 1238 transp_uio.uio_rw = UIO_WRITE; 1239 break; 1240 } 1241 transp_uio.uio_td = uio->uio_td; 1242 error = uiomove_fromphys(td->td_ma, 1243 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK, 1244 xfersize, &transp_uio); 1245 adv = xfersize - transp_uio.uio_resid; 1246 pgadv = 1247 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) - 1248 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT); 1249 td->td_ma += pgadv; 1250 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1251 pgadv)); 1252 td->td_ma_cnt -= pgadv; 1253 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv; 1254 uio->uio_iov->iov_len -= adv; 1255 uio->uio_resid -= adv; 1256 uio->uio_offset += adv; 1257 return (error); 1258 } 1259 1260 int 1261 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize, 1262 struct uio *uio) 1263 { 1264 struct thread *td; 1265 vm_offset_t iov_base; 1266 int cnt, pgadv; 1267 1268 td = curthread; 1269 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1270 uio->uio_segflg != UIO_USERSPACE) 1271 return (uiomove_fromphys(ma, offset, xfersize, uio)); 1272 1273 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1274 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize; 1275 iov_base = (vm_offset_t)uio->uio_iov->iov_base; 1276 switch (uio->uio_rw) { 1277 case UIO_WRITE: 1278 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma, 1279 offset, cnt); 1280 break; 1281 case UIO_READ: 1282 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK, 1283 cnt); 1284 break; 1285 } 1286 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT); 1287 td->td_ma += pgadv; 1288 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1289 pgadv)); 1290 td->td_ma_cnt -= pgadv; 1291 uio->uio_iov->iov_base = (char *)(iov_base + cnt); 1292 uio->uio_iov->iov_len -= cnt; 1293 uio->uio_resid -= cnt; 1294 uio->uio_offset += cnt; 1295 return (0); 1296 } 1297 1298 1299 /* 1300 * File table truncate routine. 1301 */ 1302 static int 1303 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1304 struct thread *td) 1305 { 1306 struct vattr vattr; 1307 struct mount *mp; 1308 struct vnode *vp; 1309 void *rl_cookie; 1310 int error; 1311 1312 vp = fp->f_vnode; 1313 1314 /* 1315 * Lock the whole range for truncation. Otherwise split i/o 1316 * might happen partly before and partly after the truncation. 1317 */ 1318 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1319 error = vn_start_write(vp, &mp, V_WAIT | PCATCH); 1320 if (error) 1321 goto out1; 1322 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1323 if (vp->v_type == VDIR) { 1324 error = EISDIR; 1325 goto out; 1326 } 1327 #ifdef MAC 1328 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1329 if (error) 1330 goto out; 1331 #endif 1332 error = vn_writechk(vp); 1333 if (error == 0) { 1334 VATTR_NULL(&vattr); 1335 vattr.va_size = length; 1336 if ((fp->f_flag & O_FSYNC) != 0) 1337 vattr.va_vaflags |= VA_SYNC; 1338 error = VOP_SETATTR(vp, &vattr, fp->f_cred); 1339 } 1340 out: 1341 VOP_UNLOCK(vp, 0); 1342 vn_finished_write(mp); 1343 out1: 1344 vn_rangelock_unlock(vp, rl_cookie); 1345 return (error); 1346 } 1347 1348 /* 1349 * File table vnode stat routine. 1350 */ 1351 static int 1352 vn_statfile(fp, sb, active_cred, td) 1353 struct file *fp; 1354 struct stat *sb; 1355 struct ucred *active_cred; 1356 struct thread *td; 1357 { 1358 struct vnode *vp = fp->f_vnode; 1359 int error; 1360 1361 vn_lock(vp, LK_SHARED | LK_RETRY); 1362 error = vn_stat(vp, sb, active_cred, fp->f_cred, td); 1363 VOP_UNLOCK(vp, 0); 1364 1365 return (error); 1366 } 1367 1368 /* 1369 * Stat a vnode; implementation for the stat syscall 1370 */ 1371 int 1372 vn_stat(vp, sb, active_cred, file_cred, td) 1373 struct vnode *vp; 1374 register struct stat *sb; 1375 struct ucred *active_cred; 1376 struct ucred *file_cred; 1377 struct thread *td; 1378 { 1379 struct vattr vattr; 1380 register struct vattr *vap; 1381 int error; 1382 u_short mode; 1383 1384 AUDIT_ARG_VNODE1(vp); 1385 #ifdef MAC 1386 error = mac_vnode_check_stat(active_cred, file_cred, vp); 1387 if (error) 1388 return (error); 1389 #endif 1390 1391 vap = &vattr; 1392 1393 /* 1394 * Initialize defaults for new and unusual fields, so that file 1395 * systems which don't support these fields don't need to know 1396 * about them. 1397 */ 1398 vap->va_birthtime.tv_sec = -1; 1399 vap->va_birthtime.tv_nsec = 0; 1400 vap->va_fsid = VNOVAL; 1401 vap->va_rdev = NODEV; 1402 1403 error = VOP_GETATTR(vp, vap, active_cred); 1404 if (error) 1405 return (error); 1406 1407 /* 1408 * Zero the spare stat fields 1409 */ 1410 bzero(sb, sizeof *sb); 1411 1412 /* 1413 * Copy from vattr table 1414 */ 1415 if (vap->va_fsid != VNOVAL) 1416 sb->st_dev = vap->va_fsid; 1417 else 1418 sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0]; 1419 sb->st_ino = vap->va_fileid; 1420 mode = vap->va_mode; 1421 switch (vap->va_type) { 1422 case VREG: 1423 mode |= S_IFREG; 1424 break; 1425 case VDIR: 1426 mode |= S_IFDIR; 1427 break; 1428 case VBLK: 1429 mode |= S_IFBLK; 1430 break; 1431 case VCHR: 1432 mode |= S_IFCHR; 1433 break; 1434 case VLNK: 1435 mode |= S_IFLNK; 1436 break; 1437 case VSOCK: 1438 mode |= S_IFSOCK; 1439 break; 1440 case VFIFO: 1441 mode |= S_IFIFO; 1442 break; 1443 default: 1444 return (EBADF); 1445 } 1446 sb->st_mode = mode; 1447 sb->st_nlink = vap->va_nlink; 1448 sb->st_uid = vap->va_uid; 1449 sb->st_gid = vap->va_gid; 1450 sb->st_rdev = vap->va_rdev; 1451 if (vap->va_size > OFF_MAX) 1452 return (EOVERFLOW); 1453 sb->st_size = vap->va_size; 1454 sb->st_atim = vap->va_atime; 1455 sb->st_mtim = vap->va_mtime; 1456 sb->st_ctim = vap->va_ctime; 1457 sb->st_birthtim = vap->va_birthtime; 1458 1459 /* 1460 * According to www.opengroup.org, the meaning of st_blksize is 1461 * "a filesystem-specific preferred I/O block size for this 1462 * object. In some filesystem types, this may vary from file 1463 * to file" 1464 * Use miminum/default of PAGE_SIZE (e.g. for VCHR). 1465 */ 1466 1467 sb->st_blksize = max(PAGE_SIZE, vap->va_blocksize); 1468 1469 sb->st_flags = vap->va_flags; 1470 if (priv_check(td, PRIV_VFS_GENERATION)) 1471 sb->st_gen = 0; 1472 else 1473 sb->st_gen = vap->va_gen; 1474 1475 sb->st_blocks = vap->va_bytes / S_BLKSIZE; 1476 return (0); 1477 } 1478 1479 /* 1480 * File table vnode ioctl routine. 1481 */ 1482 static int 1483 vn_ioctl(fp, com, data, active_cred, td) 1484 struct file *fp; 1485 u_long com; 1486 void *data; 1487 struct ucred *active_cred; 1488 struct thread *td; 1489 { 1490 struct vattr vattr; 1491 struct vnode *vp; 1492 int error; 1493 1494 vp = fp->f_vnode; 1495 switch (vp->v_type) { 1496 case VDIR: 1497 case VREG: 1498 switch (com) { 1499 case FIONREAD: 1500 vn_lock(vp, LK_SHARED | LK_RETRY); 1501 error = VOP_GETATTR(vp, &vattr, active_cred); 1502 VOP_UNLOCK(vp, 0); 1503 if (error == 0) 1504 *(int *)data = vattr.va_size - fp->f_offset; 1505 return (error); 1506 case FIONBIO: 1507 case FIOASYNC: 1508 return (0); 1509 default: 1510 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1511 active_cred, td)); 1512 } 1513 default: 1514 return (ENOTTY); 1515 } 1516 } 1517 1518 /* 1519 * File table vnode poll routine. 1520 */ 1521 static int 1522 vn_poll(fp, events, active_cred, td) 1523 struct file *fp; 1524 int events; 1525 struct ucred *active_cred; 1526 struct thread *td; 1527 { 1528 struct vnode *vp; 1529 int error; 1530 1531 vp = fp->f_vnode; 1532 #ifdef MAC 1533 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1534 AUDIT_ARG_VNODE1(vp); 1535 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp); 1536 VOP_UNLOCK(vp, 0); 1537 if (!error) 1538 #endif 1539 1540 error = VOP_POLL(vp, events, fp->f_cred, td); 1541 return (error); 1542 } 1543 1544 /* 1545 * Acquire the requested lock and then check for validity. LK_RETRY 1546 * permits vn_lock to return doomed vnodes. 1547 */ 1548 int 1549 _vn_lock(struct vnode *vp, int flags, char *file, int line) 1550 { 1551 int error; 1552 1553 VNASSERT((flags & LK_TYPE_MASK) != 0, vp, 1554 ("vn_lock: no locktype")); 1555 VNASSERT(vp->v_holdcnt != 0, vp, ("vn_lock: zero hold count")); 1556 retry: 1557 error = VOP_LOCK1(vp, flags, file, line); 1558 flags &= ~LK_INTERLOCK; /* Interlock is always dropped. */ 1559 KASSERT((flags & LK_RETRY) == 0 || error == 0, 1560 ("vn_lock: error %d incompatible with flags %#x", error, flags)); 1561 1562 if ((flags & LK_RETRY) == 0) { 1563 if (error == 0 && (vp->v_iflag & VI_DOOMED) != 0) { 1564 VOP_UNLOCK(vp, 0); 1565 error = ENOENT; 1566 } 1567 } else if (error != 0) 1568 goto retry; 1569 return (error); 1570 } 1571 1572 /* 1573 * File table vnode close routine. 1574 */ 1575 static int 1576 vn_closefile(struct file *fp, struct thread *td) 1577 { 1578 struct vnode *vp; 1579 struct flock lf; 1580 int error; 1581 bool ref; 1582 1583 vp = fp->f_vnode; 1584 fp->f_ops = &badfileops; 1585 ref= (fp->f_flag & FHASLOCK) != 0 && fp->f_type == DTYPE_VNODE; 1586 1587 error = vn_close1(vp, fp->f_flag, fp->f_cred, td, ref); 1588 1589 if (__predict_false(ref)) { 1590 lf.l_whence = SEEK_SET; 1591 lf.l_start = 0; 1592 lf.l_len = 0; 1593 lf.l_type = F_UNLCK; 1594 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK); 1595 vrele(vp); 1596 } 1597 return (error); 1598 } 1599 1600 static bool 1601 vn_suspendable(struct mount *mp) 1602 { 1603 1604 return (mp->mnt_op->vfs_susp_clean != NULL); 1605 } 1606 1607 /* 1608 * Preparing to start a filesystem write operation. If the operation is 1609 * permitted, then we bump the count of operations in progress and 1610 * proceed. If a suspend request is in progress, we wait until the 1611 * suspension is over, and then proceed. 1612 */ 1613 static int 1614 vn_start_write_locked(struct mount *mp, int flags) 1615 { 1616 int error, mflags; 1617 1618 mtx_assert(MNT_MTX(mp), MA_OWNED); 1619 error = 0; 1620 1621 /* 1622 * Check on status of suspension. 1623 */ 1624 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 || 1625 mp->mnt_susp_owner != curthread) { 1626 mflags = ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? 1627 (flags & PCATCH) : 0) | (PUSER - 1); 1628 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1629 if (flags & V_NOWAIT) { 1630 error = EWOULDBLOCK; 1631 goto unlock; 1632 } 1633 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, 1634 "suspfs", 0); 1635 if (error) 1636 goto unlock; 1637 } 1638 } 1639 if (flags & V_XSLEEP) 1640 goto unlock; 1641 mp->mnt_writeopcount++; 1642 unlock: 1643 if (error != 0 || (flags & V_XSLEEP) != 0) 1644 MNT_REL(mp); 1645 MNT_IUNLOCK(mp); 1646 return (error); 1647 } 1648 1649 int 1650 vn_start_write(struct vnode *vp, struct mount **mpp, int flags) 1651 { 1652 struct mount *mp; 1653 int error; 1654 1655 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL), 1656 ("V_MNTREF requires mp")); 1657 1658 error = 0; 1659 /* 1660 * If a vnode is provided, get and return the mount point that 1661 * to which it will write. 1662 */ 1663 if (vp != NULL) { 1664 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1665 *mpp = NULL; 1666 if (error != EOPNOTSUPP) 1667 return (error); 1668 return (0); 1669 } 1670 } 1671 if ((mp = *mpp) == NULL) 1672 return (0); 1673 1674 if (!vn_suspendable(mp)) { 1675 if (vp != NULL || (flags & V_MNTREF) != 0) 1676 vfs_rel(mp); 1677 return (0); 1678 } 1679 1680 /* 1681 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1682 * a vfs_ref(). 1683 * As long as a vnode is not provided we need to acquire a 1684 * refcount for the provided mountpoint too, in order to 1685 * emulate a vfs_ref(). 1686 */ 1687 MNT_ILOCK(mp); 1688 if (vp == NULL && (flags & V_MNTREF) == 0) 1689 MNT_REF(mp); 1690 1691 return (vn_start_write_locked(mp, flags)); 1692 } 1693 1694 /* 1695 * Secondary suspension. Used by operations such as vop_inactive 1696 * routines that are needed by the higher level functions. These 1697 * are allowed to proceed until all the higher level functions have 1698 * completed (indicated by mnt_writeopcount dropping to zero). At that 1699 * time, these operations are halted until the suspension is over. 1700 */ 1701 int 1702 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags) 1703 { 1704 struct mount *mp; 1705 int error; 1706 1707 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL), 1708 ("V_MNTREF requires mp")); 1709 1710 retry: 1711 if (vp != NULL) { 1712 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1713 *mpp = NULL; 1714 if (error != EOPNOTSUPP) 1715 return (error); 1716 return (0); 1717 } 1718 } 1719 /* 1720 * If we are not suspended or have not yet reached suspended 1721 * mode, then let the operation proceed. 1722 */ 1723 if ((mp = *mpp) == NULL) 1724 return (0); 1725 1726 if (!vn_suspendable(mp)) { 1727 if (vp != NULL || (flags & V_MNTREF) != 0) 1728 vfs_rel(mp); 1729 return (0); 1730 } 1731 1732 /* 1733 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1734 * a vfs_ref(). 1735 * As long as a vnode is not provided we need to acquire a 1736 * refcount for the provided mountpoint too, in order to 1737 * emulate a vfs_ref(). 1738 */ 1739 MNT_ILOCK(mp); 1740 if (vp == NULL && (flags & V_MNTREF) == 0) 1741 MNT_REF(mp); 1742 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) { 1743 mp->mnt_secondary_writes++; 1744 mp->mnt_secondary_accwrites++; 1745 MNT_IUNLOCK(mp); 1746 return (0); 1747 } 1748 if (flags & V_NOWAIT) { 1749 MNT_REL(mp); 1750 MNT_IUNLOCK(mp); 1751 return (EWOULDBLOCK); 1752 } 1753 /* 1754 * Wait for the suspension to finish. 1755 */ 1756 error = msleep(&mp->mnt_flag, MNT_MTX(mp), (PUSER - 1) | PDROP | 1757 ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? (flags & PCATCH) : 0), 1758 "suspfs", 0); 1759 vfs_rel(mp); 1760 if (error == 0) 1761 goto retry; 1762 return (error); 1763 } 1764 1765 /* 1766 * Filesystem write operation has completed. If we are suspending and this 1767 * operation is the last one, notify the suspender that the suspension is 1768 * now in effect. 1769 */ 1770 void 1771 vn_finished_write(mp) 1772 struct mount *mp; 1773 { 1774 if (mp == NULL || !vn_suspendable(mp)) 1775 return; 1776 MNT_ILOCK(mp); 1777 MNT_REL(mp); 1778 mp->mnt_writeopcount--; 1779 if (mp->mnt_writeopcount < 0) 1780 panic("vn_finished_write: neg cnt"); 1781 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 1782 mp->mnt_writeopcount <= 0) 1783 wakeup(&mp->mnt_writeopcount); 1784 MNT_IUNLOCK(mp); 1785 } 1786 1787 1788 /* 1789 * Filesystem secondary write operation has completed. If we are 1790 * suspending and this operation is the last one, notify the suspender 1791 * that the suspension is now in effect. 1792 */ 1793 void 1794 vn_finished_secondary_write(mp) 1795 struct mount *mp; 1796 { 1797 if (mp == NULL || !vn_suspendable(mp)) 1798 return; 1799 MNT_ILOCK(mp); 1800 MNT_REL(mp); 1801 mp->mnt_secondary_writes--; 1802 if (mp->mnt_secondary_writes < 0) 1803 panic("vn_finished_secondary_write: neg cnt"); 1804 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 1805 mp->mnt_secondary_writes <= 0) 1806 wakeup(&mp->mnt_secondary_writes); 1807 MNT_IUNLOCK(mp); 1808 } 1809 1810 1811 1812 /* 1813 * Request a filesystem to suspend write operations. 1814 */ 1815 int 1816 vfs_write_suspend(struct mount *mp, int flags) 1817 { 1818 int error; 1819 1820 MPASS(vn_suspendable(mp)); 1821 1822 MNT_ILOCK(mp); 1823 if (mp->mnt_susp_owner == curthread) { 1824 MNT_IUNLOCK(mp); 1825 return (EALREADY); 1826 } 1827 while (mp->mnt_kern_flag & MNTK_SUSPEND) 1828 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0); 1829 1830 /* 1831 * Unmount holds a write reference on the mount point. If we 1832 * own busy reference and drain for writers, we deadlock with 1833 * the reference draining in the unmount path. Callers of 1834 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if 1835 * vfs_busy() reference is owned and caller is not in the 1836 * unmount context. 1837 */ 1838 if ((flags & VS_SKIP_UNMOUNT) != 0 && 1839 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) { 1840 MNT_IUNLOCK(mp); 1841 return (EBUSY); 1842 } 1843 1844 mp->mnt_kern_flag |= MNTK_SUSPEND; 1845 mp->mnt_susp_owner = curthread; 1846 if (mp->mnt_writeopcount > 0) 1847 (void) msleep(&mp->mnt_writeopcount, 1848 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0); 1849 else 1850 MNT_IUNLOCK(mp); 1851 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0) 1852 vfs_write_resume(mp, 0); 1853 return (error); 1854 } 1855 1856 /* 1857 * Request a filesystem to resume write operations. 1858 */ 1859 void 1860 vfs_write_resume(struct mount *mp, int flags) 1861 { 1862 1863 MPASS(vn_suspendable(mp)); 1864 1865 MNT_ILOCK(mp); 1866 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1867 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner")); 1868 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 | 1869 MNTK_SUSPENDED); 1870 mp->mnt_susp_owner = NULL; 1871 wakeup(&mp->mnt_writeopcount); 1872 wakeup(&mp->mnt_flag); 1873 curthread->td_pflags &= ~TDP_IGNSUSP; 1874 if ((flags & VR_START_WRITE) != 0) { 1875 MNT_REF(mp); 1876 mp->mnt_writeopcount++; 1877 } 1878 MNT_IUNLOCK(mp); 1879 if ((flags & VR_NO_SUSPCLR) == 0) 1880 VFS_SUSP_CLEAN(mp); 1881 } else if ((flags & VR_START_WRITE) != 0) { 1882 MNT_REF(mp); 1883 vn_start_write_locked(mp, 0); 1884 } else { 1885 MNT_IUNLOCK(mp); 1886 } 1887 } 1888 1889 /* 1890 * Helper loop around vfs_write_suspend() for filesystem unmount VFS 1891 * methods. 1892 */ 1893 int 1894 vfs_write_suspend_umnt(struct mount *mp) 1895 { 1896 int error; 1897 1898 MPASS(vn_suspendable(mp)); 1899 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0, 1900 ("vfs_write_suspend_umnt: recursed")); 1901 1902 /* dounmount() already called vn_start_write(). */ 1903 for (;;) { 1904 vn_finished_write(mp); 1905 error = vfs_write_suspend(mp, 0); 1906 if (error != 0) { 1907 vn_start_write(NULL, &mp, V_WAIT); 1908 return (error); 1909 } 1910 MNT_ILOCK(mp); 1911 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0) 1912 break; 1913 MNT_IUNLOCK(mp); 1914 vn_start_write(NULL, &mp, V_WAIT); 1915 } 1916 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2); 1917 wakeup(&mp->mnt_flag); 1918 MNT_IUNLOCK(mp); 1919 curthread->td_pflags |= TDP_IGNSUSP; 1920 return (0); 1921 } 1922 1923 /* 1924 * Implement kqueues for files by translating it to vnode operation. 1925 */ 1926 static int 1927 vn_kqfilter(struct file *fp, struct knote *kn) 1928 { 1929 1930 return (VOP_KQFILTER(fp->f_vnode, kn)); 1931 } 1932 1933 /* 1934 * Simplified in-kernel wrapper calls for extended attribute access. 1935 * Both calls pass in a NULL credential, authorizing as "kernel" access. 1936 * Set IO_NODELOCKED in ioflg if the vnode is already locked. 1937 */ 1938 int 1939 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace, 1940 const char *attrname, int *buflen, char *buf, struct thread *td) 1941 { 1942 struct uio auio; 1943 struct iovec iov; 1944 int error; 1945 1946 iov.iov_len = *buflen; 1947 iov.iov_base = buf; 1948 1949 auio.uio_iov = &iov; 1950 auio.uio_iovcnt = 1; 1951 auio.uio_rw = UIO_READ; 1952 auio.uio_segflg = UIO_SYSSPACE; 1953 auio.uio_td = td; 1954 auio.uio_offset = 0; 1955 auio.uio_resid = *buflen; 1956 1957 if ((ioflg & IO_NODELOCKED) == 0) 1958 vn_lock(vp, LK_SHARED | LK_RETRY); 1959 1960 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 1961 1962 /* authorize attribute retrieval as kernel */ 1963 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL, 1964 td); 1965 1966 if ((ioflg & IO_NODELOCKED) == 0) 1967 VOP_UNLOCK(vp, 0); 1968 1969 if (error == 0) { 1970 *buflen = *buflen - auio.uio_resid; 1971 } 1972 1973 return (error); 1974 } 1975 1976 /* 1977 * XXX failure mode if partially written? 1978 */ 1979 int 1980 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace, 1981 const char *attrname, int buflen, char *buf, struct thread *td) 1982 { 1983 struct uio auio; 1984 struct iovec iov; 1985 struct mount *mp; 1986 int error; 1987 1988 iov.iov_len = buflen; 1989 iov.iov_base = buf; 1990 1991 auio.uio_iov = &iov; 1992 auio.uio_iovcnt = 1; 1993 auio.uio_rw = UIO_WRITE; 1994 auio.uio_segflg = UIO_SYSSPACE; 1995 auio.uio_td = td; 1996 auio.uio_offset = 0; 1997 auio.uio_resid = buflen; 1998 1999 if ((ioflg & IO_NODELOCKED) == 0) { 2000 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2001 return (error); 2002 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2003 } 2004 2005 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2006 2007 /* authorize attribute setting as kernel */ 2008 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td); 2009 2010 if ((ioflg & IO_NODELOCKED) == 0) { 2011 vn_finished_write(mp); 2012 VOP_UNLOCK(vp, 0); 2013 } 2014 2015 return (error); 2016 } 2017 2018 int 2019 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace, 2020 const char *attrname, struct thread *td) 2021 { 2022 struct mount *mp; 2023 int error; 2024 2025 if ((ioflg & IO_NODELOCKED) == 0) { 2026 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2027 return (error); 2028 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2029 } 2030 2031 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2032 2033 /* authorize attribute removal as kernel */ 2034 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td); 2035 if (error == EOPNOTSUPP) 2036 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL, 2037 NULL, td); 2038 2039 if ((ioflg & IO_NODELOCKED) == 0) { 2040 vn_finished_write(mp); 2041 VOP_UNLOCK(vp, 0); 2042 } 2043 2044 return (error); 2045 } 2046 2047 static int 2048 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags, 2049 struct vnode **rvp) 2050 { 2051 2052 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp)); 2053 } 2054 2055 int 2056 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp) 2057 { 2058 2059 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino, 2060 lkflags, rvp)); 2061 } 2062 2063 int 2064 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg, 2065 int lkflags, struct vnode **rvp) 2066 { 2067 struct mount *mp; 2068 int ltype, error; 2069 2070 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get"); 2071 mp = vp->v_mount; 2072 ltype = VOP_ISLOCKED(vp); 2073 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED, 2074 ("vn_vget_ino: vp not locked")); 2075 error = vfs_busy(mp, MBF_NOWAIT); 2076 if (error != 0) { 2077 vfs_ref(mp); 2078 VOP_UNLOCK(vp, 0); 2079 error = vfs_busy(mp, 0); 2080 vn_lock(vp, ltype | LK_RETRY); 2081 vfs_rel(mp); 2082 if (error != 0) 2083 return (ENOENT); 2084 if (vp->v_iflag & VI_DOOMED) { 2085 vfs_unbusy(mp); 2086 return (ENOENT); 2087 } 2088 } 2089 VOP_UNLOCK(vp, 0); 2090 error = alloc(mp, alloc_arg, lkflags, rvp); 2091 vfs_unbusy(mp); 2092 if (*rvp != vp) 2093 vn_lock(vp, ltype | LK_RETRY); 2094 if (vp->v_iflag & VI_DOOMED) { 2095 if (error == 0) { 2096 if (*rvp == vp) 2097 vunref(vp); 2098 else 2099 vput(*rvp); 2100 } 2101 error = ENOENT; 2102 } 2103 return (error); 2104 } 2105 2106 int 2107 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio, 2108 struct thread *td) 2109 { 2110 2111 if (vp->v_type != VREG || td == NULL) 2112 return (0); 2113 if ((uoff_t)uio->uio_offset + uio->uio_resid > 2114 lim_cur(td, RLIMIT_FSIZE)) { 2115 PROC_LOCK(td->td_proc); 2116 kern_psignal(td->td_proc, SIGXFSZ); 2117 PROC_UNLOCK(td->td_proc); 2118 return (EFBIG); 2119 } 2120 return (0); 2121 } 2122 2123 int 2124 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 2125 struct thread *td) 2126 { 2127 struct vnode *vp; 2128 2129 vp = fp->f_vnode; 2130 #ifdef AUDIT 2131 vn_lock(vp, LK_SHARED | LK_RETRY); 2132 AUDIT_ARG_VNODE1(vp); 2133 VOP_UNLOCK(vp, 0); 2134 #endif 2135 return (setfmode(td, active_cred, vp, mode)); 2136 } 2137 2138 int 2139 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 2140 struct thread *td) 2141 { 2142 struct vnode *vp; 2143 2144 vp = fp->f_vnode; 2145 #ifdef AUDIT 2146 vn_lock(vp, LK_SHARED | LK_RETRY); 2147 AUDIT_ARG_VNODE1(vp); 2148 VOP_UNLOCK(vp, 0); 2149 #endif 2150 return (setfown(td, active_cred, vp, uid, gid)); 2151 } 2152 2153 void 2154 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 2155 { 2156 vm_object_t object; 2157 2158 if ((object = vp->v_object) == NULL) 2159 return; 2160 VM_OBJECT_WLOCK(object); 2161 vm_object_page_remove(object, start, end, 0); 2162 VM_OBJECT_WUNLOCK(object); 2163 } 2164 2165 int 2166 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred) 2167 { 2168 struct vattr va; 2169 daddr_t bn, bnp; 2170 uint64_t bsize; 2171 off_t noff; 2172 int error; 2173 2174 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2175 ("Wrong command %lu", cmd)); 2176 2177 if (vn_lock(vp, LK_SHARED) != 0) 2178 return (EBADF); 2179 if (vp->v_type != VREG) { 2180 error = ENOTTY; 2181 goto unlock; 2182 } 2183 error = VOP_GETATTR(vp, &va, cred); 2184 if (error != 0) 2185 goto unlock; 2186 noff = *off; 2187 if (noff >= va.va_size) { 2188 error = ENXIO; 2189 goto unlock; 2190 } 2191 bsize = vp->v_mount->mnt_stat.f_iosize; 2192 for (bn = noff / bsize; noff < va.va_size; bn++, noff += bsize) { 2193 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL); 2194 if (error == EOPNOTSUPP) { 2195 error = ENOTTY; 2196 goto unlock; 2197 } 2198 if ((bnp == -1 && cmd == FIOSEEKHOLE) || 2199 (bnp != -1 && cmd == FIOSEEKDATA)) { 2200 noff = bn * bsize; 2201 if (noff < *off) 2202 noff = *off; 2203 goto unlock; 2204 } 2205 } 2206 if (noff > va.va_size) 2207 noff = va.va_size; 2208 /* noff == va.va_size. There is an implicit hole at the end of file. */ 2209 if (cmd == FIOSEEKDATA) 2210 error = ENXIO; 2211 unlock: 2212 VOP_UNLOCK(vp, 0); 2213 if (error == 0) 2214 *off = noff; 2215 return (error); 2216 } 2217 2218 int 2219 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td) 2220 { 2221 struct ucred *cred; 2222 struct vnode *vp; 2223 struct vattr vattr; 2224 off_t foffset, size; 2225 int error, noneg; 2226 2227 cred = td->td_ucred; 2228 vp = fp->f_vnode; 2229 foffset = foffset_lock(fp, 0); 2230 noneg = (vp->v_type != VCHR); 2231 error = 0; 2232 switch (whence) { 2233 case L_INCR: 2234 if (noneg && 2235 (foffset < 0 || 2236 (offset > 0 && foffset > OFF_MAX - offset))) { 2237 error = EOVERFLOW; 2238 break; 2239 } 2240 offset += foffset; 2241 break; 2242 case L_XTND: 2243 vn_lock(vp, LK_SHARED | LK_RETRY); 2244 error = VOP_GETATTR(vp, &vattr, cred); 2245 VOP_UNLOCK(vp, 0); 2246 if (error) 2247 break; 2248 2249 /* 2250 * If the file references a disk device, then fetch 2251 * the media size and use that to determine the ending 2252 * offset. 2253 */ 2254 if (vattr.va_size == 0 && vp->v_type == VCHR && 2255 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0) 2256 vattr.va_size = size; 2257 if (noneg && 2258 (vattr.va_size > OFF_MAX || 2259 (offset > 0 && vattr.va_size > OFF_MAX - offset))) { 2260 error = EOVERFLOW; 2261 break; 2262 } 2263 offset += vattr.va_size; 2264 break; 2265 case L_SET: 2266 break; 2267 case SEEK_DATA: 2268 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td); 2269 break; 2270 case SEEK_HOLE: 2271 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td); 2272 break; 2273 default: 2274 error = EINVAL; 2275 } 2276 if (error == 0 && noneg && offset < 0) 2277 error = EINVAL; 2278 if (error != 0) 2279 goto drop; 2280 VFS_KNOTE_UNLOCKED(vp, 0); 2281 td->td_uretoff.tdu_off = offset; 2282 drop: 2283 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0); 2284 return (error); 2285 } 2286 2287 int 2288 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred, 2289 struct thread *td) 2290 { 2291 int error; 2292 2293 /* 2294 * Grant permission if the caller is the owner of the file, or 2295 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on 2296 * on the file. If the time pointer is null, then write 2297 * permission on the file is also sufficient. 2298 * 2299 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes: 2300 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES 2301 * will be allowed to set the times [..] to the current 2302 * server time. 2303 */ 2304 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td); 2305 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0) 2306 error = VOP_ACCESS(vp, VWRITE, cred, td); 2307 return (error); 2308 } 2309 2310 int 2311 vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2312 { 2313 struct vnode *vp; 2314 int error; 2315 2316 if (fp->f_type == DTYPE_FIFO) 2317 kif->kf_type = KF_TYPE_FIFO; 2318 else 2319 kif->kf_type = KF_TYPE_VNODE; 2320 vp = fp->f_vnode; 2321 vref(vp); 2322 FILEDESC_SUNLOCK(fdp); 2323 error = vn_fill_kinfo_vnode(vp, kif); 2324 vrele(vp); 2325 FILEDESC_SLOCK(fdp); 2326 return (error); 2327 } 2328 2329 static inline void 2330 vn_fill_junk(struct kinfo_file *kif) 2331 { 2332 size_t len, olen; 2333 2334 /* 2335 * Simulate vn_fullpath returning changing values for a given 2336 * vp during e.g. coredump. 2337 */ 2338 len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1; 2339 olen = strlen(kif->kf_path); 2340 if (len < olen) 2341 strcpy(&kif->kf_path[len - 1], "$"); 2342 else 2343 for (; olen < len; olen++) 2344 strcpy(&kif->kf_path[olen], "A"); 2345 } 2346 2347 int 2348 vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif) 2349 { 2350 struct vattr va; 2351 char *fullpath, *freepath; 2352 int error; 2353 2354 kif->kf_vnode_type = vntype_to_kinfo(vp->v_type); 2355 freepath = NULL; 2356 fullpath = "-"; 2357 error = vn_fullpath(curthread, vp, &fullpath, &freepath); 2358 if (error == 0) { 2359 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path)); 2360 } 2361 if (freepath != NULL) 2362 free(freepath, M_TEMP); 2363 2364 KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path, 2365 vn_fill_junk(kif); 2366 ); 2367 2368 /* 2369 * Retrieve vnode attributes. 2370 */ 2371 va.va_fsid = VNOVAL; 2372 va.va_rdev = NODEV; 2373 vn_lock(vp, LK_SHARED | LK_RETRY); 2374 error = VOP_GETATTR(vp, &va, curthread->td_ucred); 2375 VOP_UNLOCK(vp, 0); 2376 if (error != 0) 2377 return (error); 2378 if (va.va_fsid != VNOVAL) 2379 kif->kf_un.kf_file.kf_file_fsid = va.va_fsid; 2380 else 2381 kif->kf_un.kf_file.kf_file_fsid = 2382 vp->v_mount->mnt_stat.f_fsid.val[0]; 2383 kif->kf_un.kf_file.kf_file_fileid = va.va_fileid; 2384 kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode); 2385 kif->kf_un.kf_file.kf_file_size = va.va_size; 2386 kif->kf_un.kf_file.kf_file_rdev = va.va_rdev; 2387 return (0); 2388 } 2389 2390 int 2391 vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size, 2392 vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff, 2393 struct thread *td) 2394 { 2395 #ifdef HWPMC_HOOKS 2396 struct pmckern_map_in pkm; 2397 #endif 2398 struct mount *mp; 2399 struct vnode *vp; 2400 vm_object_t object; 2401 vm_prot_t maxprot; 2402 boolean_t writecounted; 2403 int error; 2404 2405 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \ 2406 defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) 2407 /* 2408 * POSIX shared-memory objects are defined to have 2409 * kernel persistence, and are not defined to support 2410 * read(2)/write(2) -- or even open(2). Thus, we can 2411 * use MAP_ASYNC to trade on-disk coherence for speed. 2412 * The shm_open(3) library routine turns on the FPOSIXSHM 2413 * flag to request this behavior. 2414 */ 2415 if ((fp->f_flag & FPOSIXSHM) != 0) 2416 flags |= MAP_NOSYNC; 2417 #endif 2418 vp = fp->f_vnode; 2419 2420 /* 2421 * Ensure that file and memory protections are 2422 * compatible. Note that we only worry about 2423 * writability if mapping is shared; in this case, 2424 * current and max prot are dictated by the open file. 2425 * XXX use the vnode instead? Problem is: what 2426 * credentials do we use for determination? What if 2427 * proc does a setuid? 2428 */ 2429 mp = vp->v_mount; 2430 if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) { 2431 maxprot = VM_PROT_NONE; 2432 if ((prot & VM_PROT_EXECUTE) != 0) 2433 return (EACCES); 2434 } else 2435 maxprot = VM_PROT_EXECUTE; 2436 if ((fp->f_flag & FREAD) != 0) 2437 maxprot |= VM_PROT_READ; 2438 else if ((prot & VM_PROT_READ) != 0) 2439 return (EACCES); 2440 2441 /* 2442 * If we are sharing potential changes via MAP_SHARED and we 2443 * are trying to get write permission although we opened it 2444 * without asking for it, bail out. 2445 */ 2446 if ((flags & MAP_SHARED) != 0) { 2447 if ((fp->f_flag & FWRITE) != 0) 2448 maxprot |= VM_PROT_WRITE; 2449 else if ((prot & VM_PROT_WRITE) != 0) 2450 return (EACCES); 2451 } else { 2452 maxprot |= VM_PROT_WRITE; 2453 cap_maxprot |= VM_PROT_WRITE; 2454 } 2455 maxprot &= cap_maxprot; 2456 2457 /* 2458 * For regular files and shared memory, POSIX requires that 2459 * the value of foff be a legitimate offset within the data 2460 * object. In particular, negative offsets are invalid. 2461 * Blocking negative offsets and overflows here avoids 2462 * possible wraparound or user-level access into reserved 2463 * ranges of the data object later. In contrast, POSIX does 2464 * not dictate how offsets are used by device drivers, so in 2465 * the case of a device mapping a negative offset is passed 2466 * on. 2467 */ 2468 if ( 2469 #ifdef _LP64 2470 size > OFF_MAX || 2471 #endif 2472 foff < 0 || foff > OFF_MAX - size) 2473 return (EINVAL); 2474 2475 writecounted = FALSE; 2476 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp, 2477 &foff, &object, &writecounted); 2478 if (error != 0) 2479 return (error); 2480 error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object, 2481 foff, writecounted, td); 2482 if (error != 0) { 2483 /* 2484 * If this mapping was accounted for in the vnode's 2485 * writecount, then undo that now. 2486 */ 2487 if (writecounted) 2488 vnode_pager_release_writecount(object, 0, size); 2489 vm_object_deallocate(object); 2490 } 2491 #ifdef HWPMC_HOOKS 2492 /* Inform hwpmc(4) if an executable is being mapped. */ 2493 if (PMC_HOOK_INSTALLED(PMC_FN_MMAP)) { 2494 if ((prot & VM_PROT_EXECUTE) != 0 && error == 0) { 2495 pkm.pm_file = vp; 2496 pkm.pm_address = (uintptr_t) *addr; 2497 PMC_CALL_HOOK(td, PMC_FN_MMAP, (void *) &pkm); 2498 } 2499 } 2500 #endif 2501 return (error); 2502 }
Cache object: 0830a95a31ccde120200f4dbef20c9fe
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