FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_vnops.c
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/11.2/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(struct vnode *vp)
415 {
416
417 ASSERT_VOP_LOCKED(vp, "vn_writechk");
418 /*
419 * If there's shared text associated with
420 * the vnode, try to free it up once. If
421 * we fail, we can't allow writing.
422 */
423 if (VOP_IS_TEXT(vp))
424 return (ETXTBSY);
425
426 return (0);
427 }
428
429 /*
430 * Vnode close call
431 */
432 static int
433 vn_close1(struct vnode *vp, int flags, struct ucred *file_cred,
434 struct thread *td, bool keep_ref)
435 {
436 struct mount *mp;
437 int error, lock_flags;
438
439 if (vp->v_type != VFIFO && (flags & FWRITE) == 0 &&
440 MNT_EXTENDED_SHARED(vp->v_mount))
441 lock_flags = LK_SHARED;
442 else
443 lock_flags = LK_EXCLUSIVE;
444
445 vn_start_write(vp, &mp, V_WAIT);
446 vn_lock(vp, lock_flags | LK_RETRY);
447 AUDIT_ARG_VNODE1(vp);
448 if ((flags & (FWRITE | FOPENFAILED)) == FWRITE) {
449 VNASSERT(vp->v_writecount > 0, vp,
450 ("vn_close: negative writecount"));
451 VOP_ADD_WRITECOUNT(vp, -1);
452 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
453 __func__, vp, vp->v_writecount);
454 }
455 error = VOP_CLOSE(vp, flags, file_cred, td);
456 if (keep_ref)
457 VOP_UNLOCK(vp, 0);
458 else
459 vput(vp);
460 vn_finished_write(mp);
461 return (error);
462 }
463
464 int
465 vn_close(struct vnode *vp, int flags, struct ucred *file_cred,
466 struct thread *td)
467 {
468
469 return (vn_close1(vp, flags, file_cred, td, false));
470 }
471
472 /*
473 * Heuristic to detect sequential operation.
474 */
475 static int
476 sequential_heuristic(struct uio *uio, struct file *fp)
477 {
478
479 ASSERT_VOP_LOCKED(fp->f_vnode, __func__);
480 if (fp->f_flag & FRDAHEAD)
481 return (fp->f_seqcount << IO_SEQSHIFT);
482
483 /*
484 * Offset 0 is handled specially. open() sets f_seqcount to 1 so
485 * that the first I/O is normally considered to be slightly
486 * sequential. Seeking to offset 0 doesn't change sequentiality
487 * unless previous seeks have reduced f_seqcount to 0, in which
488 * case offset 0 is not special.
489 */
490 if ((uio->uio_offset == 0 && fp->f_seqcount > 0) ||
491 uio->uio_offset == fp->f_nextoff) {
492 /*
493 * f_seqcount is in units of fixed-size blocks so that it
494 * depends mainly on the amount of sequential I/O and not
495 * much on the number of sequential I/O's. The fixed size
496 * of 16384 is hard-coded here since it is (not quite) just
497 * a magic size that works well here. This size is more
498 * closely related to the best I/O size for real disks than
499 * to any block size used by software.
500 */
501 fp->f_seqcount += howmany(uio->uio_resid, 16384);
502 if (fp->f_seqcount > IO_SEQMAX)
503 fp->f_seqcount = IO_SEQMAX;
504 return (fp->f_seqcount << IO_SEQSHIFT);
505 }
506
507 /* Not sequential. Quickly draw-down sequentiality. */
508 if (fp->f_seqcount > 1)
509 fp->f_seqcount = 1;
510 else
511 fp->f_seqcount = 0;
512 return (0);
513 }
514
515 /*
516 * Package up an I/O request on a vnode into a uio and do it.
517 */
518 int
519 vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset,
520 enum uio_seg segflg, int ioflg, struct ucred *active_cred,
521 struct ucred *file_cred, ssize_t *aresid, struct thread *td)
522 {
523 struct uio auio;
524 struct iovec aiov;
525 struct mount *mp;
526 struct ucred *cred;
527 void *rl_cookie;
528 struct vn_io_fault_args args;
529 int error, lock_flags;
530
531 if (offset < 0 && vp->v_type != VCHR)
532 return (EINVAL);
533 auio.uio_iov = &aiov;
534 auio.uio_iovcnt = 1;
535 aiov.iov_base = base;
536 aiov.iov_len = len;
537 auio.uio_resid = len;
538 auio.uio_offset = offset;
539 auio.uio_segflg = segflg;
540 auio.uio_rw = rw;
541 auio.uio_td = td;
542 error = 0;
543
544 if ((ioflg & IO_NODELOCKED) == 0) {
545 if ((ioflg & IO_RANGELOCKED) == 0) {
546 if (rw == UIO_READ) {
547 rl_cookie = vn_rangelock_rlock(vp, offset,
548 offset + len);
549 } else {
550 rl_cookie = vn_rangelock_wlock(vp, offset,
551 offset + len);
552 }
553 } else
554 rl_cookie = NULL;
555 mp = NULL;
556 if (rw == UIO_WRITE) {
557 if (vp->v_type != VCHR &&
558 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH))
559 != 0)
560 goto out;
561 if (MNT_SHARED_WRITES(mp) ||
562 ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount)))
563 lock_flags = LK_SHARED;
564 else
565 lock_flags = LK_EXCLUSIVE;
566 } else
567 lock_flags = LK_SHARED;
568 vn_lock(vp, lock_flags | LK_RETRY);
569 } else
570 rl_cookie = NULL;
571
572 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
573 #ifdef MAC
574 if ((ioflg & IO_NOMACCHECK) == 0) {
575 if (rw == UIO_READ)
576 error = mac_vnode_check_read(active_cred, file_cred,
577 vp);
578 else
579 error = mac_vnode_check_write(active_cred, file_cred,
580 vp);
581 }
582 #endif
583 if (error == 0) {
584 if (file_cred != NULL)
585 cred = file_cred;
586 else
587 cred = active_cred;
588 if (do_vn_io_fault(vp, &auio)) {
589 args.kind = VN_IO_FAULT_VOP;
590 args.cred = cred;
591 args.flags = ioflg;
592 args.args.vop_args.vp = vp;
593 error = vn_io_fault1(vp, &auio, &args, td);
594 } else if (rw == UIO_READ) {
595 error = VOP_READ(vp, &auio, ioflg, cred);
596 } else /* if (rw == UIO_WRITE) */ {
597 error = VOP_WRITE(vp, &auio, ioflg, cred);
598 }
599 }
600 if (aresid)
601 *aresid = auio.uio_resid;
602 else
603 if (auio.uio_resid && error == 0)
604 error = EIO;
605 if ((ioflg & IO_NODELOCKED) == 0) {
606 VOP_UNLOCK(vp, 0);
607 if (mp != NULL)
608 vn_finished_write(mp);
609 }
610 out:
611 if (rl_cookie != NULL)
612 vn_rangelock_unlock(vp, rl_cookie);
613 return (error);
614 }
615
616 /*
617 * Package up an I/O request on a vnode into a uio and do it. The I/O
618 * request is split up into smaller chunks and we try to avoid saturating
619 * the buffer cache while potentially holding a vnode locked, so we
620 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield()
621 * to give other processes a chance to lock the vnode (either other processes
622 * core'ing the same binary, or unrelated processes scanning the directory).
623 */
624 int
625 vn_rdwr_inchunks(rw, vp, base, len, offset, segflg, ioflg, active_cred,
626 file_cred, aresid, td)
627 enum uio_rw rw;
628 struct vnode *vp;
629 void *base;
630 size_t len;
631 off_t offset;
632 enum uio_seg segflg;
633 int ioflg;
634 struct ucred *active_cred;
635 struct ucred *file_cred;
636 size_t *aresid;
637 struct thread *td;
638 {
639 int error = 0;
640 ssize_t iaresid;
641
642 do {
643 int chunk;
644
645 /*
646 * Force `offset' to a multiple of MAXBSIZE except possibly
647 * for the first chunk, so that filesystems only need to
648 * write full blocks except possibly for the first and last
649 * chunks.
650 */
651 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE;
652
653 if (chunk > len)
654 chunk = len;
655 if (rw != UIO_READ && vp->v_type == VREG)
656 bwillwrite();
657 iaresid = 0;
658 error = vn_rdwr(rw, vp, base, chunk, offset, segflg,
659 ioflg, active_cred, file_cred, &iaresid, td);
660 len -= chunk; /* aresid calc already includes length */
661 if (error)
662 break;
663 offset += chunk;
664 base = (char *)base + chunk;
665 kern_yield(PRI_USER);
666 } while (len);
667 if (aresid)
668 *aresid = len + iaresid;
669 return (error);
670 }
671
672 off_t
673 foffset_lock(struct file *fp, int flags)
674 {
675 struct mtx *mtxp;
676 off_t res;
677
678 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
679
680 #if OFF_MAX <= LONG_MAX
681 /*
682 * Caller only wants the current f_offset value. Assume that
683 * the long and shorter integer types reads are atomic.
684 */
685 if ((flags & FOF_NOLOCK) != 0)
686 return (fp->f_offset);
687 #endif
688
689 /*
690 * According to McKusick the vn lock was protecting f_offset here.
691 * It is now protected by the FOFFSET_LOCKED flag.
692 */
693 mtxp = mtx_pool_find(mtxpool_sleep, fp);
694 mtx_lock(mtxp);
695 if ((flags & FOF_NOLOCK) == 0) {
696 while (fp->f_vnread_flags & FOFFSET_LOCKED) {
697 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING;
698 msleep(&fp->f_vnread_flags, mtxp, PUSER -1,
699 "vofflock", 0);
700 }
701 fp->f_vnread_flags |= FOFFSET_LOCKED;
702 }
703 res = fp->f_offset;
704 mtx_unlock(mtxp);
705 return (res);
706 }
707
708 void
709 foffset_unlock(struct file *fp, off_t val, int flags)
710 {
711 struct mtx *mtxp;
712
713 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
714
715 #if OFF_MAX <= LONG_MAX
716 if ((flags & FOF_NOLOCK) != 0) {
717 if ((flags & FOF_NOUPDATE) == 0)
718 fp->f_offset = val;
719 if ((flags & FOF_NEXTOFF) != 0)
720 fp->f_nextoff = val;
721 return;
722 }
723 #endif
724
725 mtxp = mtx_pool_find(mtxpool_sleep, fp);
726 mtx_lock(mtxp);
727 if ((flags & FOF_NOUPDATE) == 0)
728 fp->f_offset = val;
729 if ((flags & FOF_NEXTOFF) != 0)
730 fp->f_nextoff = val;
731 if ((flags & FOF_NOLOCK) == 0) {
732 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0,
733 ("Lost FOFFSET_LOCKED"));
734 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING)
735 wakeup(&fp->f_vnread_flags);
736 fp->f_vnread_flags = 0;
737 }
738 mtx_unlock(mtxp);
739 }
740
741 void
742 foffset_lock_uio(struct file *fp, struct uio *uio, int flags)
743 {
744
745 if ((flags & FOF_OFFSET) == 0)
746 uio->uio_offset = foffset_lock(fp, flags);
747 }
748
749 void
750 foffset_unlock_uio(struct file *fp, struct uio *uio, int flags)
751 {
752
753 if ((flags & FOF_OFFSET) == 0)
754 foffset_unlock(fp, uio->uio_offset, flags);
755 }
756
757 static int
758 get_advice(struct file *fp, struct uio *uio)
759 {
760 struct mtx *mtxp;
761 int ret;
762
763 ret = POSIX_FADV_NORMAL;
764 if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG)
765 return (ret);
766
767 mtxp = mtx_pool_find(mtxpool_sleep, fp);
768 mtx_lock(mtxp);
769 if (fp->f_advice != NULL &&
770 uio->uio_offset >= fp->f_advice->fa_start &&
771 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end)
772 ret = fp->f_advice->fa_advice;
773 mtx_unlock(mtxp);
774 return (ret);
775 }
776
777 /*
778 * File table vnode read routine.
779 */
780 static int
781 vn_read(fp, uio, active_cred, flags, td)
782 struct file *fp;
783 struct uio *uio;
784 struct ucred *active_cred;
785 int flags;
786 struct thread *td;
787 {
788 struct vnode *vp;
789 off_t orig_offset;
790 int error, ioflag;
791 int advice;
792
793 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
794 uio->uio_td, td));
795 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET"));
796 vp = fp->f_vnode;
797 ioflag = 0;
798 if (fp->f_flag & FNONBLOCK)
799 ioflag |= IO_NDELAY;
800 if (fp->f_flag & O_DIRECT)
801 ioflag |= IO_DIRECT;
802 advice = get_advice(fp, uio);
803 vn_lock(vp, LK_SHARED | LK_RETRY);
804
805 switch (advice) {
806 case POSIX_FADV_NORMAL:
807 case POSIX_FADV_SEQUENTIAL:
808 case POSIX_FADV_NOREUSE:
809 ioflag |= sequential_heuristic(uio, fp);
810 break;
811 case POSIX_FADV_RANDOM:
812 /* Disable read-ahead for random I/O. */
813 break;
814 }
815 orig_offset = uio->uio_offset;
816
817 #ifdef MAC
818 error = mac_vnode_check_read(active_cred, fp->f_cred, vp);
819 if (error == 0)
820 #endif
821 error = VOP_READ(vp, uio, ioflag, fp->f_cred);
822 fp->f_nextoff = uio->uio_offset;
823 VOP_UNLOCK(vp, 0);
824 if (error == 0 && advice == POSIX_FADV_NOREUSE &&
825 orig_offset != uio->uio_offset)
826 /*
827 * Use POSIX_FADV_DONTNEED to flush pages and buffers
828 * for the backing file after a POSIX_FADV_NOREUSE
829 * read(2).
830 */
831 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1,
832 POSIX_FADV_DONTNEED);
833 return (error);
834 }
835
836 /*
837 * File table vnode write routine.
838 */
839 static int
840 vn_write(fp, uio, active_cred, flags, td)
841 struct file *fp;
842 struct uio *uio;
843 struct ucred *active_cred;
844 int flags;
845 struct thread *td;
846 {
847 struct vnode *vp;
848 struct mount *mp;
849 off_t orig_offset;
850 int error, ioflag, lock_flags;
851 int advice;
852
853 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
854 uio->uio_td, td));
855 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET"));
856 vp = fp->f_vnode;
857 if (vp->v_type == VREG)
858 bwillwrite();
859 ioflag = IO_UNIT;
860 if (vp->v_type == VREG && (fp->f_flag & O_APPEND))
861 ioflag |= IO_APPEND;
862 if (fp->f_flag & FNONBLOCK)
863 ioflag |= IO_NDELAY;
864 if (fp->f_flag & O_DIRECT)
865 ioflag |= IO_DIRECT;
866 if ((fp->f_flag & O_FSYNC) ||
867 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS)))
868 ioflag |= IO_SYNC;
869 mp = NULL;
870 if (vp->v_type != VCHR &&
871 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
872 goto unlock;
873
874 advice = get_advice(fp, uio);
875
876 if (MNT_SHARED_WRITES(mp) ||
877 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) {
878 lock_flags = LK_SHARED;
879 } else {
880 lock_flags = LK_EXCLUSIVE;
881 }
882
883 vn_lock(vp, lock_flags | LK_RETRY);
884 switch (advice) {
885 case POSIX_FADV_NORMAL:
886 case POSIX_FADV_SEQUENTIAL:
887 case POSIX_FADV_NOREUSE:
888 ioflag |= sequential_heuristic(uio, fp);
889 break;
890 case POSIX_FADV_RANDOM:
891 /* XXX: Is this correct? */
892 break;
893 }
894 orig_offset = uio->uio_offset;
895
896 #ifdef MAC
897 error = mac_vnode_check_write(active_cred, fp->f_cred, vp);
898 if (error == 0)
899 #endif
900 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred);
901 fp->f_nextoff = uio->uio_offset;
902 VOP_UNLOCK(vp, 0);
903 if (vp->v_type != VCHR)
904 vn_finished_write(mp);
905 if (error == 0 && advice == POSIX_FADV_NOREUSE &&
906 orig_offset != uio->uio_offset)
907 /*
908 * Use POSIX_FADV_DONTNEED to flush pages and buffers
909 * for the backing file after a POSIX_FADV_NOREUSE
910 * write(2).
911 */
912 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1,
913 POSIX_FADV_DONTNEED);
914 unlock:
915 return (error);
916 }
917
918 /*
919 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to
920 * prevent the following deadlock:
921 *
922 * Assume that the thread A reads from the vnode vp1 into userspace
923 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is
924 * currently not resident, then system ends up with the call chain
925 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] ->
926 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2)
927 * which establishes lock order vp1->vn_lock, then vp2->vn_lock.
928 * If, at the same time, thread B reads from vnode vp2 into buffer buf2
929 * backed by the pages of vnode vp1, and some page in buf2 is not
930 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock.
931 *
932 * To prevent the lock order reversal and deadlock, vn_io_fault() does
933 * not allow page faults to happen during VOP_READ() or VOP_WRITE().
934 * Instead, it first tries to do the whole range i/o with pagefaults
935 * disabled. If all pages in the i/o buffer are resident and mapped,
936 * VOP will succeed (ignoring the genuine filesystem errors).
937 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do
938 * i/o in chunks, with all pages in the chunk prefaulted and held
939 * using vm_fault_quick_hold_pages().
940 *
941 * Filesystems using this deadlock avoidance scheme should use the
942 * array of the held pages from uio, saved in the curthread->td_ma,
943 * instead of doing uiomove(). A helper function
944 * vn_io_fault_uiomove() converts uiomove request into
945 * uiomove_fromphys() over td_ma array.
946 *
947 * Since vnode locks do not cover the whole i/o anymore, rangelocks
948 * make the current i/o request atomic with respect to other i/os and
949 * truncations.
950 */
951
952 /*
953 * Decode vn_io_fault_args and perform the corresponding i/o.
954 */
955 static int
956 vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio,
957 struct thread *td)
958 {
959 int error, save;
960
961 error = 0;
962 save = vm_fault_disable_pagefaults();
963 switch (args->kind) {
964 case VN_IO_FAULT_FOP:
965 error = (args->args.fop_args.doio)(args->args.fop_args.fp,
966 uio, args->cred, args->flags, td);
967 break;
968 case VN_IO_FAULT_VOP:
969 if (uio->uio_rw == UIO_READ) {
970 error = VOP_READ(args->args.vop_args.vp, uio,
971 args->flags, args->cred);
972 } else if (uio->uio_rw == UIO_WRITE) {
973 error = VOP_WRITE(args->args.vop_args.vp, uio,
974 args->flags, args->cred);
975 }
976 break;
977 default:
978 panic("vn_io_fault_doio: unknown kind of io %d %d",
979 args->kind, uio->uio_rw);
980 }
981 vm_fault_enable_pagefaults(save);
982 return (error);
983 }
984
985 static int
986 vn_io_fault_touch(char *base, const struct uio *uio)
987 {
988 int r;
989
990 r = fubyte(base);
991 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1))
992 return (EFAULT);
993 return (0);
994 }
995
996 static int
997 vn_io_fault_prefault_user(const struct uio *uio)
998 {
999 char *base;
1000 const struct iovec *iov;
1001 size_t len;
1002 ssize_t resid;
1003 int error, i;
1004
1005 KASSERT(uio->uio_segflg == UIO_USERSPACE,
1006 ("vn_io_fault_prefault userspace"));
1007
1008 error = i = 0;
1009 iov = uio->uio_iov;
1010 resid = uio->uio_resid;
1011 base = iov->iov_base;
1012 len = iov->iov_len;
1013 while (resid > 0) {
1014 error = vn_io_fault_touch(base, uio);
1015 if (error != 0)
1016 break;
1017 if (len < PAGE_SIZE) {
1018 if (len != 0) {
1019 error = vn_io_fault_touch(base + len - 1, uio);
1020 if (error != 0)
1021 break;
1022 resid -= len;
1023 }
1024 if (++i >= uio->uio_iovcnt)
1025 break;
1026 iov = uio->uio_iov + i;
1027 base = iov->iov_base;
1028 len = iov->iov_len;
1029 } else {
1030 len -= PAGE_SIZE;
1031 base += PAGE_SIZE;
1032 resid -= PAGE_SIZE;
1033 }
1034 }
1035 return (error);
1036 }
1037
1038 /*
1039 * Common code for vn_io_fault(), agnostic to the kind of i/o request.
1040 * Uses vn_io_fault_doio() to make the call to an actual i/o function.
1041 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request
1042 * into args and call vn_io_fault1() to handle faults during the user
1043 * mode buffer accesses.
1044 */
1045 static int
1046 vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args,
1047 struct thread *td)
1048 {
1049 vm_page_t ma[io_hold_cnt + 2];
1050 struct uio *uio_clone, short_uio;
1051 struct iovec short_iovec[1];
1052 vm_page_t *prev_td_ma;
1053 vm_prot_t prot;
1054 vm_offset_t addr, end;
1055 size_t len, resid;
1056 ssize_t adv;
1057 int error, cnt, saveheld, prev_td_ma_cnt;
1058
1059 if (vn_io_fault_prefault) {
1060 error = vn_io_fault_prefault_user(uio);
1061 if (error != 0)
1062 return (error); /* Or ignore ? */
1063 }
1064
1065 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ;
1066
1067 /*
1068 * The UFS follows IO_UNIT directive and replays back both
1069 * uio_offset and uio_resid if an error is encountered during the
1070 * operation. But, since the iovec may be already advanced,
1071 * uio is still in an inconsistent state.
1072 *
1073 * Cache a copy of the original uio, which is advanced to the redo
1074 * point using UIO_NOCOPY below.
1075 */
1076 uio_clone = cloneuio(uio);
1077 resid = uio->uio_resid;
1078
1079 short_uio.uio_segflg = UIO_USERSPACE;
1080 short_uio.uio_rw = uio->uio_rw;
1081 short_uio.uio_td = uio->uio_td;
1082
1083 error = vn_io_fault_doio(args, uio, td);
1084 if (error != EFAULT)
1085 goto out;
1086
1087 atomic_add_long(&vn_io_faults_cnt, 1);
1088 uio_clone->uio_segflg = UIO_NOCOPY;
1089 uiomove(NULL, resid - uio->uio_resid, uio_clone);
1090 uio_clone->uio_segflg = uio->uio_segflg;
1091
1092 saveheld = curthread_pflags_set(TDP_UIOHELD);
1093 prev_td_ma = td->td_ma;
1094 prev_td_ma_cnt = td->td_ma_cnt;
1095
1096 while (uio_clone->uio_resid != 0) {
1097 len = uio_clone->uio_iov->iov_len;
1098 if (len == 0) {
1099 KASSERT(uio_clone->uio_iovcnt >= 1,
1100 ("iovcnt underflow"));
1101 uio_clone->uio_iov++;
1102 uio_clone->uio_iovcnt--;
1103 continue;
1104 }
1105 if (len > io_hold_cnt * PAGE_SIZE)
1106 len = io_hold_cnt * PAGE_SIZE;
1107 addr = (uintptr_t)uio_clone->uio_iov->iov_base;
1108 end = round_page(addr + len);
1109 if (end < addr) {
1110 error = EFAULT;
1111 break;
1112 }
1113 cnt = atop(end - trunc_page(addr));
1114 /*
1115 * A perfectly misaligned address and length could cause
1116 * both the start and the end of the chunk to use partial
1117 * page. +2 accounts for such a situation.
1118 */
1119 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map,
1120 addr, len, prot, ma, io_hold_cnt + 2);
1121 if (cnt == -1) {
1122 error = EFAULT;
1123 break;
1124 }
1125 short_uio.uio_iov = &short_iovec[0];
1126 short_iovec[0].iov_base = (void *)addr;
1127 short_uio.uio_iovcnt = 1;
1128 short_uio.uio_resid = short_iovec[0].iov_len = len;
1129 short_uio.uio_offset = uio_clone->uio_offset;
1130 td->td_ma = ma;
1131 td->td_ma_cnt = cnt;
1132
1133 error = vn_io_fault_doio(args, &short_uio, td);
1134 vm_page_unhold_pages(ma, cnt);
1135 adv = len - short_uio.uio_resid;
1136
1137 uio_clone->uio_iov->iov_base =
1138 (char *)uio_clone->uio_iov->iov_base + adv;
1139 uio_clone->uio_iov->iov_len -= adv;
1140 uio_clone->uio_resid -= adv;
1141 uio_clone->uio_offset += adv;
1142
1143 uio->uio_resid -= adv;
1144 uio->uio_offset += adv;
1145
1146 if (error != 0 || adv == 0)
1147 break;
1148 }
1149 td->td_ma = prev_td_ma;
1150 td->td_ma_cnt = prev_td_ma_cnt;
1151 curthread_pflags_restore(saveheld);
1152 out:
1153 free(uio_clone, M_IOV);
1154 return (error);
1155 }
1156
1157 static int
1158 vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred,
1159 int flags, struct thread *td)
1160 {
1161 fo_rdwr_t *doio;
1162 struct vnode *vp;
1163 void *rl_cookie;
1164 struct vn_io_fault_args args;
1165 int error;
1166
1167 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write;
1168 vp = fp->f_vnode;
1169 foffset_lock_uio(fp, uio, flags);
1170 if (do_vn_io_fault(vp, uio)) {
1171 args.kind = VN_IO_FAULT_FOP;
1172 args.args.fop_args.fp = fp;
1173 args.args.fop_args.doio = doio;
1174 args.cred = active_cred;
1175 args.flags = flags | FOF_OFFSET;
1176 if (uio->uio_rw == UIO_READ) {
1177 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset,
1178 uio->uio_offset + uio->uio_resid);
1179 } else if ((fp->f_flag & O_APPEND) != 0 ||
1180 (flags & FOF_OFFSET) == 0) {
1181 /* For appenders, punt and lock the whole range. */
1182 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
1183 } else {
1184 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset,
1185 uio->uio_offset + uio->uio_resid);
1186 }
1187 error = vn_io_fault1(vp, uio, &args, td);
1188 vn_rangelock_unlock(vp, rl_cookie);
1189 } else {
1190 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td);
1191 }
1192 foffset_unlock_uio(fp, uio, flags);
1193 return (error);
1194 }
1195
1196 /*
1197 * Helper function to perform the requested uiomove operation using
1198 * the held pages for io->uio_iov[0].iov_base buffer instead of
1199 * copyin/copyout. Access to the pages with uiomove_fromphys()
1200 * instead of iov_base prevents page faults that could occur due to
1201 * pmap_collect() invalidating the mapping created by
1202 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or
1203 * object cleanup revoking the write access from page mappings.
1204 *
1205 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove()
1206 * instead of plain uiomove().
1207 */
1208 int
1209 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio)
1210 {
1211 struct uio transp_uio;
1212 struct iovec transp_iov[1];
1213 struct thread *td;
1214 size_t adv;
1215 int error, pgadv;
1216
1217 td = curthread;
1218 if ((td->td_pflags & TDP_UIOHELD) == 0 ||
1219 uio->uio_segflg != UIO_USERSPACE)
1220 return (uiomove(data, xfersize, uio));
1221
1222 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt));
1223 transp_iov[0].iov_base = data;
1224 transp_uio.uio_iov = &transp_iov[0];
1225 transp_uio.uio_iovcnt = 1;
1226 if (xfersize > uio->uio_resid)
1227 xfersize = uio->uio_resid;
1228 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize;
1229 transp_uio.uio_offset = 0;
1230 transp_uio.uio_segflg = UIO_SYSSPACE;
1231 /*
1232 * Since transp_iov points to data, and td_ma page array
1233 * corresponds to original uio->uio_iov, we need to invert the
1234 * direction of the i/o operation as passed to
1235 * uiomove_fromphys().
1236 */
1237 switch (uio->uio_rw) {
1238 case UIO_WRITE:
1239 transp_uio.uio_rw = UIO_READ;
1240 break;
1241 case UIO_READ:
1242 transp_uio.uio_rw = UIO_WRITE;
1243 break;
1244 }
1245 transp_uio.uio_td = uio->uio_td;
1246 error = uiomove_fromphys(td->td_ma,
1247 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK,
1248 xfersize, &transp_uio);
1249 adv = xfersize - transp_uio.uio_resid;
1250 pgadv =
1251 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) -
1252 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT);
1253 td->td_ma += pgadv;
1254 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt,
1255 pgadv));
1256 td->td_ma_cnt -= pgadv;
1257 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv;
1258 uio->uio_iov->iov_len -= adv;
1259 uio->uio_resid -= adv;
1260 uio->uio_offset += adv;
1261 return (error);
1262 }
1263
1264 int
1265 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize,
1266 struct uio *uio)
1267 {
1268 struct thread *td;
1269 vm_offset_t iov_base;
1270 int cnt, pgadv;
1271
1272 td = curthread;
1273 if ((td->td_pflags & TDP_UIOHELD) == 0 ||
1274 uio->uio_segflg != UIO_USERSPACE)
1275 return (uiomove_fromphys(ma, offset, xfersize, uio));
1276
1277 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt));
1278 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize;
1279 iov_base = (vm_offset_t)uio->uio_iov->iov_base;
1280 switch (uio->uio_rw) {
1281 case UIO_WRITE:
1282 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma,
1283 offset, cnt);
1284 break;
1285 case UIO_READ:
1286 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK,
1287 cnt);
1288 break;
1289 }
1290 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT);
1291 td->td_ma += pgadv;
1292 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt,
1293 pgadv));
1294 td->td_ma_cnt -= pgadv;
1295 uio->uio_iov->iov_base = (char *)(iov_base + cnt);
1296 uio->uio_iov->iov_len -= cnt;
1297 uio->uio_resid -= cnt;
1298 uio->uio_offset += cnt;
1299 return (0);
1300 }
1301
1302
1303 /*
1304 * File table truncate routine.
1305 */
1306 static int
1307 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred,
1308 struct thread *td)
1309 {
1310 struct vattr vattr;
1311 struct mount *mp;
1312 struct vnode *vp;
1313 void *rl_cookie;
1314 int error;
1315
1316 vp = fp->f_vnode;
1317
1318 /*
1319 * Lock the whole range for truncation. Otherwise split i/o
1320 * might happen partly before and partly after the truncation.
1321 */
1322 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
1323 error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
1324 if (error)
1325 goto out1;
1326 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1327 if (vp->v_type == VDIR) {
1328 error = EISDIR;
1329 goto out;
1330 }
1331 #ifdef MAC
1332 error = mac_vnode_check_write(active_cred, fp->f_cred, vp);
1333 if (error)
1334 goto out;
1335 #endif
1336 error = vn_writechk(vp);
1337 if (error == 0) {
1338 VATTR_NULL(&vattr);
1339 vattr.va_size = length;
1340 if ((fp->f_flag & O_FSYNC) != 0)
1341 vattr.va_vaflags |= VA_SYNC;
1342 error = VOP_SETATTR(vp, &vattr, fp->f_cred);
1343 }
1344 out:
1345 VOP_UNLOCK(vp, 0);
1346 vn_finished_write(mp);
1347 out1:
1348 vn_rangelock_unlock(vp, rl_cookie);
1349 return (error);
1350 }
1351
1352 /*
1353 * File table vnode stat routine.
1354 */
1355 static int
1356 vn_statfile(fp, sb, active_cred, td)
1357 struct file *fp;
1358 struct stat *sb;
1359 struct ucred *active_cred;
1360 struct thread *td;
1361 {
1362 struct vnode *vp = fp->f_vnode;
1363 int error;
1364
1365 vn_lock(vp, LK_SHARED | LK_RETRY);
1366 error = vn_stat(vp, sb, active_cred, fp->f_cred, td);
1367 VOP_UNLOCK(vp, 0);
1368
1369 return (error);
1370 }
1371
1372 /*
1373 * Stat a vnode; implementation for the stat syscall
1374 */
1375 int
1376 vn_stat(struct vnode *vp, struct stat *sb, struct ucred *active_cred,
1377 struct ucred *file_cred, struct thread *td)
1378 {
1379 struct vattr vattr;
1380 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(struct file *fp, u_long com, void *data, struct ucred *active_cred,
1484 struct thread *td)
1485 {
1486 struct vattr vattr;
1487 struct vnode *vp;
1488 int error;
1489
1490 vp = fp->f_vnode;
1491 switch (vp->v_type) {
1492 case VDIR:
1493 case VREG:
1494 switch (com) {
1495 case FIONREAD:
1496 vn_lock(vp, LK_SHARED | LK_RETRY);
1497 error = VOP_GETATTR(vp, &vattr, active_cred);
1498 VOP_UNLOCK(vp, 0);
1499 if (error == 0)
1500 *(int *)data = vattr.va_size - fp->f_offset;
1501 return (error);
1502 case FIONBIO:
1503 case FIOASYNC:
1504 return (0);
1505 default:
1506 return (VOP_IOCTL(vp, com, data, fp->f_flag,
1507 active_cred, td));
1508 }
1509 default:
1510 return (ENOTTY);
1511 }
1512 }
1513
1514 /*
1515 * File table vnode poll routine.
1516 */
1517 static int
1518 vn_poll(struct file *fp, int events, struct ucred *active_cred,
1519 struct thread *td)
1520 {
1521 struct vnode *vp;
1522 int error;
1523
1524 vp = fp->f_vnode;
1525 #ifdef MAC
1526 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1527 AUDIT_ARG_VNODE1(vp);
1528 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp);
1529 VOP_UNLOCK(vp, 0);
1530 if (!error)
1531 #endif
1532
1533 error = VOP_POLL(vp, events, fp->f_cred, td);
1534 return (error);
1535 }
1536
1537 /*
1538 * Acquire the requested lock and then check for validity. LK_RETRY
1539 * permits vn_lock to return doomed vnodes.
1540 */
1541 int
1542 _vn_lock(struct vnode *vp, int flags, char *file, int line)
1543 {
1544 int error;
1545
1546 VNASSERT((flags & LK_TYPE_MASK) != 0, vp,
1547 ("vn_lock: no locktype"));
1548 VNASSERT(vp->v_holdcnt != 0, vp, ("vn_lock: zero hold count"));
1549 retry:
1550 error = VOP_LOCK1(vp, flags, file, line);
1551 flags &= ~LK_INTERLOCK; /* Interlock is always dropped. */
1552 KASSERT((flags & LK_RETRY) == 0 || error == 0,
1553 ("vn_lock: error %d incompatible with flags %#x", error, flags));
1554
1555 if ((flags & LK_RETRY) == 0) {
1556 if (error == 0 && (vp->v_iflag & VI_DOOMED) != 0) {
1557 VOP_UNLOCK(vp, 0);
1558 error = ENOENT;
1559 }
1560 } else if (error != 0)
1561 goto retry;
1562 return (error);
1563 }
1564
1565 /*
1566 * File table vnode close routine.
1567 */
1568 static int
1569 vn_closefile(struct file *fp, struct thread *td)
1570 {
1571 struct vnode *vp;
1572 struct flock lf;
1573 int error;
1574 bool ref;
1575
1576 vp = fp->f_vnode;
1577 fp->f_ops = &badfileops;
1578 ref= (fp->f_flag & FHASLOCK) != 0 && fp->f_type == DTYPE_VNODE;
1579
1580 error = vn_close1(vp, fp->f_flag, fp->f_cred, td, ref);
1581
1582 if (__predict_false(ref)) {
1583 lf.l_whence = SEEK_SET;
1584 lf.l_start = 0;
1585 lf.l_len = 0;
1586 lf.l_type = F_UNLCK;
1587 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK);
1588 vrele(vp);
1589 }
1590 return (error);
1591 }
1592
1593 static bool
1594 vn_suspendable(struct mount *mp)
1595 {
1596
1597 return (mp->mnt_op->vfs_susp_clean != NULL);
1598 }
1599
1600 /*
1601 * Preparing to start a filesystem write operation. If the operation is
1602 * permitted, then we bump the count of operations in progress and
1603 * proceed. If a suspend request is in progress, we wait until the
1604 * suspension is over, and then proceed.
1605 */
1606 static int
1607 vn_start_write_locked(struct mount *mp, int flags)
1608 {
1609 int error, mflags;
1610
1611 mtx_assert(MNT_MTX(mp), MA_OWNED);
1612 error = 0;
1613
1614 /*
1615 * Check on status of suspension.
1616 */
1617 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 ||
1618 mp->mnt_susp_owner != curthread) {
1619 mflags = ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ?
1620 (flags & PCATCH) : 0) | (PUSER - 1);
1621 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
1622 if (flags & V_NOWAIT) {
1623 error = EWOULDBLOCK;
1624 goto unlock;
1625 }
1626 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags,
1627 "suspfs", 0);
1628 if (error)
1629 goto unlock;
1630 }
1631 }
1632 if (flags & V_XSLEEP)
1633 goto unlock;
1634 mp->mnt_writeopcount++;
1635 unlock:
1636 if (error != 0 || (flags & V_XSLEEP) != 0)
1637 MNT_REL(mp);
1638 MNT_IUNLOCK(mp);
1639 return (error);
1640 }
1641
1642 int
1643 vn_start_write(struct vnode *vp, struct mount **mpp, int flags)
1644 {
1645 struct mount *mp;
1646 int error;
1647
1648 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
1649 ("V_MNTREF requires mp"));
1650
1651 error = 0;
1652 /*
1653 * If a vnode is provided, get and return the mount point that
1654 * to which it will write.
1655 */
1656 if (vp != NULL) {
1657 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
1658 *mpp = NULL;
1659 if (error != EOPNOTSUPP)
1660 return (error);
1661 return (0);
1662 }
1663 }
1664 if ((mp = *mpp) == NULL)
1665 return (0);
1666
1667 if (!vn_suspendable(mp)) {
1668 if (vp != NULL || (flags & V_MNTREF) != 0)
1669 vfs_rel(mp);
1670 return (0);
1671 }
1672
1673 /*
1674 * VOP_GETWRITEMOUNT() returns with the mp refcount held through
1675 * a vfs_ref().
1676 * As long as a vnode is not provided we need to acquire a
1677 * refcount for the provided mountpoint too, in order to
1678 * emulate a vfs_ref().
1679 */
1680 MNT_ILOCK(mp);
1681 if (vp == NULL && (flags & V_MNTREF) == 0)
1682 MNT_REF(mp);
1683
1684 return (vn_start_write_locked(mp, flags));
1685 }
1686
1687 /*
1688 * Secondary suspension. Used by operations such as vop_inactive
1689 * routines that are needed by the higher level functions. These
1690 * are allowed to proceed until all the higher level functions have
1691 * completed (indicated by mnt_writeopcount dropping to zero). At that
1692 * time, these operations are halted until the suspension is over.
1693 */
1694 int
1695 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags)
1696 {
1697 struct mount *mp;
1698 int error;
1699
1700 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
1701 ("V_MNTREF requires mp"));
1702
1703 retry:
1704 if (vp != NULL) {
1705 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
1706 *mpp = NULL;
1707 if (error != EOPNOTSUPP)
1708 return (error);
1709 return (0);
1710 }
1711 }
1712 /*
1713 * If we are not suspended or have not yet reached suspended
1714 * mode, then let the operation proceed.
1715 */
1716 if ((mp = *mpp) == NULL)
1717 return (0);
1718
1719 if (!vn_suspendable(mp)) {
1720 if (vp != NULL || (flags & V_MNTREF) != 0)
1721 vfs_rel(mp);
1722 return (0);
1723 }
1724
1725 /*
1726 * VOP_GETWRITEMOUNT() returns with the mp refcount held through
1727 * a vfs_ref().
1728 * As long as a vnode is not provided we need to acquire a
1729 * refcount for the provided mountpoint too, in order to
1730 * emulate a vfs_ref().
1731 */
1732 MNT_ILOCK(mp);
1733 if (vp == NULL && (flags & V_MNTREF) == 0)
1734 MNT_REF(mp);
1735 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) {
1736 mp->mnt_secondary_writes++;
1737 mp->mnt_secondary_accwrites++;
1738 MNT_IUNLOCK(mp);
1739 return (0);
1740 }
1741 if (flags & V_NOWAIT) {
1742 MNT_REL(mp);
1743 MNT_IUNLOCK(mp);
1744 return (EWOULDBLOCK);
1745 }
1746 /*
1747 * Wait for the suspension to finish.
1748 */
1749 error = msleep(&mp->mnt_flag, MNT_MTX(mp), (PUSER - 1) | PDROP |
1750 ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? (flags & PCATCH) : 0),
1751 "suspfs", 0);
1752 vfs_rel(mp);
1753 if (error == 0)
1754 goto retry;
1755 return (error);
1756 }
1757
1758 /*
1759 * Filesystem write operation has completed. If we are suspending and this
1760 * operation is the last one, notify the suspender that the suspension is
1761 * now in effect.
1762 */
1763 void
1764 vn_finished_write(struct mount *mp)
1765 {
1766 if (mp == NULL || !vn_suspendable(mp))
1767 return;
1768 MNT_ILOCK(mp);
1769 MNT_REL(mp);
1770 mp->mnt_writeopcount--;
1771 if (mp->mnt_writeopcount < 0)
1772 panic("vn_finished_write: neg cnt");
1773 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 &&
1774 mp->mnt_writeopcount <= 0)
1775 wakeup(&mp->mnt_writeopcount);
1776 MNT_IUNLOCK(mp);
1777 }
1778
1779
1780 /*
1781 * Filesystem secondary write operation has completed. If we are
1782 * suspending and this operation is the last one, notify the suspender
1783 * that the suspension is now in effect.
1784 */
1785 void
1786 vn_finished_secondary_write(struct mount *mp)
1787 {
1788 if (mp == NULL || !vn_suspendable(mp))
1789 return;
1790 MNT_ILOCK(mp);
1791 MNT_REL(mp);
1792 mp->mnt_secondary_writes--;
1793 if (mp->mnt_secondary_writes < 0)
1794 panic("vn_finished_secondary_write: neg cnt");
1795 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 &&
1796 mp->mnt_secondary_writes <= 0)
1797 wakeup(&mp->mnt_secondary_writes);
1798 MNT_IUNLOCK(mp);
1799 }
1800
1801
1802
1803 /*
1804 * Request a filesystem to suspend write operations.
1805 */
1806 int
1807 vfs_write_suspend(struct mount *mp, int flags)
1808 {
1809 int error;
1810
1811 MPASS(vn_suspendable(mp));
1812
1813 MNT_ILOCK(mp);
1814 if (mp->mnt_susp_owner == curthread) {
1815 MNT_IUNLOCK(mp);
1816 return (EALREADY);
1817 }
1818 while (mp->mnt_kern_flag & MNTK_SUSPEND)
1819 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0);
1820
1821 /*
1822 * Unmount holds a write reference on the mount point. If we
1823 * own busy reference and drain for writers, we deadlock with
1824 * the reference draining in the unmount path. Callers of
1825 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if
1826 * vfs_busy() reference is owned and caller is not in the
1827 * unmount context.
1828 */
1829 if ((flags & VS_SKIP_UNMOUNT) != 0 &&
1830 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) {
1831 MNT_IUNLOCK(mp);
1832 return (EBUSY);
1833 }
1834
1835 mp->mnt_kern_flag |= MNTK_SUSPEND;
1836 mp->mnt_susp_owner = curthread;
1837 if (mp->mnt_writeopcount > 0)
1838 (void) msleep(&mp->mnt_writeopcount,
1839 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0);
1840 else
1841 MNT_IUNLOCK(mp);
1842 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0)
1843 vfs_write_resume(mp, 0);
1844 return (error);
1845 }
1846
1847 /*
1848 * Request a filesystem to resume write operations.
1849 */
1850 void
1851 vfs_write_resume(struct mount *mp, int flags)
1852 {
1853
1854 MPASS(vn_suspendable(mp));
1855
1856 MNT_ILOCK(mp);
1857 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
1858 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner"));
1859 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 |
1860 MNTK_SUSPENDED);
1861 mp->mnt_susp_owner = NULL;
1862 wakeup(&mp->mnt_writeopcount);
1863 wakeup(&mp->mnt_flag);
1864 curthread->td_pflags &= ~TDP_IGNSUSP;
1865 if ((flags & VR_START_WRITE) != 0) {
1866 MNT_REF(mp);
1867 mp->mnt_writeopcount++;
1868 }
1869 MNT_IUNLOCK(mp);
1870 if ((flags & VR_NO_SUSPCLR) == 0)
1871 VFS_SUSP_CLEAN(mp);
1872 } else if ((flags & VR_START_WRITE) != 0) {
1873 MNT_REF(mp);
1874 vn_start_write_locked(mp, 0);
1875 } else {
1876 MNT_IUNLOCK(mp);
1877 }
1878 }
1879
1880 /*
1881 * Helper loop around vfs_write_suspend() for filesystem unmount VFS
1882 * methods.
1883 */
1884 int
1885 vfs_write_suspend_umnt(struct mount *mp)
1886 {
1887 int error;
1888
1889 MPASS(vn_suspendable(mp));
1890 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0,
1891 ("vfs_write_suspend_umnt: recursed"));
1892
1893 /* dounmount() already called vn_start_write(). */
1894 for (;;) {
1895 vn_finished_write(mp);
1896 error = vfs_write_suspend(mp, 0);
1897 if (error != 0) {
1898 vn_start_write(NULL, &mp, V_WAIT);
1899 return (error);
1900 }
1901 MNT_ILOCK(mp);
1902 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0)
1903 break;
1904 MNT_IUNLOCK(mp);
1905 vn_start_write(NULL, &mp, V_WAIT);
1906 }
1907 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2);
1908 wakeup(&mp->mnt_flag);
1909 MNT_IUNLOCK(mp);
1910 curthread->td_pflags |= TDP_IGNSUSP;
1911 return (0);
1912 }
1913
1914 /*
1915 * Implement kqueues for files by translating it to vnode operation.
1916 */
1917 static int
1918 vn_kqfilter(struct file *fp, struct knote *kn)
1919 {
1920
1921 return (VOP_KQFILTER(fp->f_vnode, kn));
1922 }
1923
1924 /*
1925 * Simplified in-kernel wrapper calls for extended attribute access.
1926 * Both calls pass in a NULL credential, authorizing as "kernel" access.
1927 * Set IO_NODELOCKED in ioflg if the vnode is already locked.
1928 */
1929 int
1930 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace,
1931 const char *attrname, int *buflen, char *buf, struct thread *td)
1932 {
1933 struct uio auio;
1934 struct iovec iov;
1935 int error;
1936
1937 iov.iov_len = *buflen;
1938 iov.iov_base = buf;
1939
1940 auio.uio_iov = &iov;
1941 auio.uio_iovcnt = 1;
1942 auio.uio_rw = UIO_READ;
1943 auio.uio_segflg = UIO_SYSSPACE;
1944 auio.uio_td = td;
1945 auio.uio_offset = 0;
1946 auio.uio_resid = *buflen;
1947
1948 if ((ioflg & IO_NODELOCKED) == 0)
1949 vn_lock(vp, LK_SHARED | LK_RETRY);
1950
1951 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
1952
1953 /* authorize attribute retrieval as kernel */
1954 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL,
1955 td);
1956
1957 if ((ioflg & IO_NODELOCKED) == 0)
1958 VOP_UNLOCK(vp, 0);
1959
1960 if (error == 0) {
1961 *buflen = *buflen - auio.uio_resid;
1962 }
1963
1964 return (error);
1965 }
1966
1967 /*
1968 * XXX failure mode if partially written?
1969 */
1970 int
1971 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace,
1972 const char *attrname, int buflen, char *buf, struct thread *td)
1973 {
1974 struct uio auio;
1975 struct iovec iov;
1976 struct mount *mp;
1977 int error;
1978
1979 iov.iov_len = buflen;
1980 iov.iov_base = buf;
1981
1982 auio.uio_iov = &iov;
1983 auio.uio_iovcnt = 1;
1984 auio.uio_rw = UIO_WRITE;
1985 auio.uio_segflg = UIO_SYSSPACE;
1986 auio.uio_td = td;
1987 auio.uio_offset = 0;
1988 auio.uio_resid = buflen;
1989
1990 if ((ioflg & IO_NODELOCKED) == 0) {
1991 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0)
1992 return (error);
1993 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1994 }
1995
1996 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
1997
1998 /* authorize attribute setting as kernel */
1999 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td);
2000
2001 if ((ioflg & IO_NODELOCKED) == 0) {
2002 vn_finished_write(mp);
2003 VOP_UNLOCK(vp, 0);
2004 }
2005
2006 return (error);
2007 }
2008
2009 int
2010 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace,
2011 const char *attrname, struct thread *td)
2012 {
2013 struct mount *mp;
2014 int error;
2015
2016 if ((ioflg & IO_NODELOCKED) == 0) {
2017 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0)
2018 return (error);
2019 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2020 }
2021
2022 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
2023
2024 /* authorize attribute removal as kernel */
2025 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td);
2026 if (error == EOPNOTSUPP)
2027 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL,
2028 NULL, td);
2029
2030 if ((ioflg & IO_NODELOCKED) == 0) {
2031 vn_finished_write(mp);
2032 VOP_UNLOCK(vp, 0);
2033 }
2034
2035 return (error);
2036 }
2037
2038 static int
2039 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags,
2040 struct vnode **rvp)
2041 {
2042
2043 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp));
2044 }
2045
2046 int
2047 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp)
2048 {
2049
2050 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino,
2051 lkflags, rvp));
2052 }
2053
2054 int
2055 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg,
2056 int lkflags, struct vnode **rvp)
2057 {
2058 struct mount *mp;
2059 int ltype, error;
2060
2061 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get");
2062 mp = vp->v_mount;
2063 ltype = VOP_ISLOCKED(vp);
2064 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED,
2065 ("vn_vget_ino: vp not locked"));
2066 error = vfs_busy(mp, MBF_NOWAIT);
2067 if (error != 0) {
2068 vfs_ref(mp);
2069 VOP_UNLOCK(vp, 0);
2070 error = vfs_busy(mp, 0);
2071 vn_lock(vp, ltype | LK_RETRY);
2072 vfs_rel(mp);
2073 if (error != 0)
2074 return (ENOENT);
2075 if (vp->v_iflag & VI_DOOMED) {
2076 vfs_unbusy(mp);
2077 return (ENOENT);
2078 }
2079 }
2080 VOP_UNLOCK(vp, 0);
2081 error = alloc(mp, alloc_arg, lkflags, rvp);
2082 vfs_unbusy(mp);
2083 if (*rvp != vp)
2084 vn_lock(vp, ltype | LK_RETRY);
2085 if (vp->v_iflag & VI_DOOMED) {
2086 if (error == 0) {
2087 if (*rvp == vp)
2088 vunref(vp);
2089 else
2090 vput(*rvp);
2091 }
2092 error = ENOENT;
2093 }
2094 return (error);
2095 }
2096
2097 int
2098 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio,
2099 struct thread *td)
2100 {
2101
2102 if (vp->v_type != VREG || td == NULL)
2103 return (0);
2104 if ((uoff_t)uio->uio_offset + uio->uio_resid >
2105 lim_cur(td, RLIMIT_FSIZE)) {
2106 PROC_LOCK(td->td_proc);
2107 kern_psignal(td->td_proc, SIGXFSZ);
2108 PROC_UNLOCK(td->td_proc);
2109 return (EFBIG);
2110 }
2111 return (0);
2112 }
2113
2114 int
2115 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred,
2116 struct thread *td)
2117 {
2118 struct vnode *vp;
2119
2120 vp = fp->f_vnode;
2121 #ifdef AUDIT
2122 vn_lock(vp, LK_SHARED | LK_RETRY);
2123 AUDIT_ARG_VNODE1(vp);
2124 VOP_UNLOCK(vp, 0);
2125 #endif
2126 return (setfmode(td, active_cred, vp, mode));
2127 }
2128
2129 int
2130 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
2131 struct thread *td)
2132 {
2133 struct vnode *vp;
2134
2135 vp = fp->f_vnode;
2136 #ifdef AUDIT
2137 vn_lock(vp, LK_SHARED | LK_RETRY);
2138 AUDIT_ARG_VNODE1(vp);
2139 VOP_UNLOCK(vp, 0);
2140 #endif
2141 return (setfown(td, active_cred, vp, uid, gid));
2142 }
2143
2144 void
2145 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end)
2146 {
2147 vm_object_t object;
2148
2149 if ((object = vp->v_object) == NULL)
2150 return;
2151 VM_OBJECT_WLOCK(object);
2152 vm_object_page_remove(object, start, end, 0);
2153 VM_OBJECT_WUNLOCK(object);
2154 }
2155
2156 int
2157 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred)
2158 {
2159 struct vattr va;
2160 daddr_t bn, bnp;
2161 uint64_t bsize;
2162 off_t noff;
2163 int error;
2164
2165 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA,
2166 ("Wrong command %lu", cmd));
2167
2168 if (vn_lock(vp, LK_SHARED) != 0)
2169 return (EBADF);
2170 if (vp->v_type != VREG) {
2171 error = ENOTTY;
2172 goto unlock;
2173 }
2174 error = VOP_GETATTR(vp, &va, cred);
2175 if (error != 0)
2176 goto unlock;
2177 noff = *off;
2178 if (noff >= va.va_size) {
2179 error = ENXIO;
2180 goto unlock;
2181 }
2182 bsize = vp->v_mount->mnt_stat.f_iosize;
2183 for (bn = noff / bsize; noff < va.va_size; bn++, noff += bsize) {
2184 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL);
2185 if (error == EOPNOTSUPP) {
2186 error = ENOTTY;
2187 goto unlock;
2188 }
2189 if ((bnp == -1 && cmd == FIOSEEKHOLE) ||
2190 (bnp != -1 && cmd == FIOSEEKDATA)) {
2191 noff = bn * bsize;
2192 if (noff < *off)
2193 noff = *off;
2194 goto unlock;
2195 }
2196 }
2197 if (noff > va.va_size)
2198 noff = va.va_size;
2199 /* noff == va.va_size. There is an implicit hole at the end of file. */
2200 if (cmd == FIOSEEKDATA)
2201 error = ENXIO;
2202 unlock:
2203 VOP_UNLOCK(vp, 0);
2204 if (error == 0)
2205 *off = noff;
2206 return (error);
2207 }
2208
2209 int
2210 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td)
2211 {
2212 struct ucred *cred;
2213 struct vnode *vp;
2214 struct vattr vattr;
2215 off_t foffset, size;
2216 int error, noneg;
2217
2218 cred = td->td_ucred;
2219 vp = fp->f_vnode;
2220 foffset = foffset_lock(fp, 0);
2221 noneg = (vp->v_type != VCHR);
2222 error = 0;
2223 switch (whence) {
2224 case L_INCR:
2225 if (noneg &&
2226 (foffset < 0 ||
2227 (offset > 0 && foffset > OFF_MAX - offset))) {
2228 error = EOVERFLOW;
2229 break;
2230 }
2231 offset += foffset;
2232 break;
2233 case L_XTND:
2234 vn_lock(vp, LK_SHARED | LK_RETRY);
2235 error = VOP_GETATTR(vp, &vattr, cred);
2236 VOP_UNLOCK(vp, 0);
2237 if (error)
2238 break;
2239
2240 /*
2241 * If the file references a disk device, then fetch
2242 * the media size and use that to determine the ending
2243 * offset.
2244 */
2245 if (vattr.va_size == 0 && vp->v_type == VCHR &&
2246 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0)
2247 vattr.va_size = size;
2248 if (noneg &&
2249 (vattr.va_size > OFF_MAX ||
2250 (offset > 0 && vattr.va_size > OFF_MAX - offset))) {
2251 error = EOVERFLOW;
2252 break;
2253 }
2254 offset += vattr.va_size;
2255 break;
2256 case L_SET:
2257 break;
2258 case SEEK_DATA:
2259 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td);
2260 break;
2261 case SEEK_HOLE:
2262 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td);
2263 break;
2264 default:
2265 error = EINVAL;
2266 }
2267 if (error == 0 && noneg && offset < 0)
2268 error = EINVAL;
2269 if (error != 0)
2270 goto drop;
2271 VFS_KNOTE_UNLOCKED(vp, 0);
2272 td->td_uretoff.tdu_off = offset;
2273 drop:
2274 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0);
2275 return (error);
2276 }
2277
2278 int
2279 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred,
2280 struct thread *td)
2281 {
2282 int error;
2283
2284 /*
2285 * Grant permission if the caller is the owner of the file, or
2286 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on
2287 * on the file. If the time pointer is null, then write
2288 * permission on the file is also sufficient.
2289 *
2290 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes:
2291 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES
2292 * will be allowed to set the times [..] to the current
2293 * server time.
2294 */
2295 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td);
2296 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0)
2297 error = VOP_ACCESS(vp, VWRITE, cred, td);
2298 return (error);
2299 }
2300
2301 int
2302 vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
2303 {
2304 struct vnode *vp;
2305 int error;
2306
2307 if (fp->f_type == DTYPE_FIFO)
2308 kif->kf_type = KF_TYPE_FIFO;
2309 else
2310 kif->kf_type = KF_TYPE_VNODE;
2311 vp = fp->f_vnode;
2312 vref(vp);
2313 FILEDESC_SUNLOCK(fdp);
2314 error = vn_fill_kinfo_vnode(vp, kif);
2315 vrele(vp);
2316 FILEDESC_SLOCK(fdp);
2317 return (error);
2318 }
2319
2320 static inline void
2321 vn_fill_junk(struct kinfo_file *kif)
2322 {
2323 size_t len, olen;
2324
2325 /*
2326 * Simulate vn_fullpath returning changing values for a given
2327 * vp during e.g. coredump.
2328 */
2329 len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1;
2330 olen = strlen(kif->kf_path);
2331 if (len < olen)
2332 strcpy(&kif->kf_path[len - 1], "$");
2333 else
2334 for (; olen < len; olen++)
2335 strcpy(&kif->kf_path[olen], "A");
2336 }
2337
2338 int
2339 vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif)
2340 {
2341 struct vattr va;
2342 char *fullpath, *freepath;
2343 int error;
2344
2345 kif->kf_vnode_type = vntype_to_kinfo(vp->v_type);
2346 freepath = NULL;
2347 fullpath = "-";
2348 error = vn_fullpath(curthread, vp, &fullpath, &freepath);
2349 if (error == 0) {
2350 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path));
2351 }
2352 if (freepath != NULL)
2353 free(freepath, M_TEMP);
2354
2355 KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path,
2356 vn_fill_junk(kif);
2357 );
2358
2359 /*
2360 * Retrieve vnode attributes.
2361 */
2362 va.va_fsid = VNOVAL;
2363 va.va_rdev = NODEV;
2364 vn_lock(vp, LK_SHARED | LK_RETRY);
2365 error = VOP_GETATTR(vp, &va, curthread->td_ucred);
2366 VOP_UNLOCK(vp, 0);
2367 if (error != 0)
2368 return (error);
2369 if (va.va_fsid != VNOVAL)
2370 kif->kf_un.kf_file.kf_file_fsid = va.va_fsid;
2371 else
2372 kif->kf_un.kf_file.kf_file_fsid =
2373 vp->v_mount->mnt_stat.f_fsid.val[0];
2374 kif->kf_un.kf_file.kf_file_fileid = va.va_fileid;
2375 kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode);
2376 kif->kf_un.kf_file.kf_file_size = va.va_size;
2377 kif->kf_un.kf_file.kf_file_rdev = va.va_rdev;
2378 return (0);
2379 }
2380
2381 int
2382 vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size,
2383 vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff,
2384 struct thread *td)
2385 {
2386 #ifdef HWPMC_HOOKS
2387 struct pmckern_map_in pkm;
2388 #endif
2389 struct mount *mp;
2390 struct vnode *vp;
2391 vm_object_t object;
2392 vm_prot_t maxprot;
2393 boolean_t writecounted;
2394 int error;
2395
2396 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \
2397 defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4)
2398 /*
2399 * POSIX shared-memory objects are defined to have
2400 * kernel persistence, and are not defined to support
2401 * read(2)/write(2) -- or even open(2). Thus, we can
2402 * use MAP_ASYNC to trade on-disk coherence for speed.
2403 * The shm_open(3) library routine turns on the FPOSIXSHM
2404 * flag to request this behavior.
2405 */
2406 if ((fp->f_flag & FPOSIXSHM) != 0)
2407 flags |= MAP_NOSYNC;
2408 #endif
2409 vp = fp->f_vnode;
2410
2411 /*
2412 * Ensure that file and memory protections are
2413 * compatible. Note that we only worry about
2414 * writability if mapping is shared; in this case,
2415 * current and max prot are dictated by the open file.
2416 * XXX use the vnode instead? Problem is: what
2417 * credentials do we use for determination? What if
2418 * proc does a setuid?
2419 */
2420 mp = vp->v_mount;
2421 if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) {
2422 maxprot = VM_PROT_NONE;
2423 if ((prot & VM_PROT_EXECUTE) != 0)
2424 return (EACCES);
2425 } else
2426 maxprot = VM_PROT_EXECUTE;
2427 if ((fp->f_flag & FREAD) != 0)
2428 maxprot |= VM_PROT_READ;
2429 else if ((prot & VM_PROT_READ) != 0)
2430 return (EACCES);
2431
2432 /*
2433 * If we are sharing potential changes via MAP_SHARED and we
2434 * are trying to get write permission although we opened it
2435 * without asking for it, bail out.
2436 */
2437 if ((flags & MAP_SHARED) != 0) {
2438 if ((fp->f_flag & FWRITE) != 0)
2439 maxprot |= VM_PROT_WRITE;
2440 else if ((prot & VM_PROT_WRITE) != 0)
2441 return (EACCES);
2442 } else {
2443 maxprot |= VM_PROT_WRITE;
2444 cap_maxprot |= VM_PROT_WRITE;
2445 }
2446 maxprot &= cap_maxprot;
2447
2448 /*
2449 * For regular files and shared memory, POSIX requires that
2450 * the value of foff be a legitimate offset within the data
2451 * object. In particular, negative offsets are invalid.
2452 * Blocking negative offsets and overflows here avoids
2453 * possible wraparound or user-level access into reserved
2454 * ranges of the data object later. In contrast, POSIX does
2455 * not dictate how offsets are used by device drivers, so in
2456 * the case of a device mapping a negative offset is passed
2457 * on.
2458 */
2459 if (
2460 #ifdef _LP64
2461 size > OFF_MAX ||
2462 #endif
2463 foff < 0 || foff > OFF_MAX - size)
2464 return (EINVAL);
2465
2466 writecounted = FALSE;
2467 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp,
2468 &foff, &object, &writecounted);
2469 if (error != 0)
2470 return (error);
2471 error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object,
2472 foff, writecounted, td);
2473 if (error != 0) {
2474 /*
2475 * If this mapping was accounted for in the vnode's
2476 * writecount, then undo that now.
2477 */
2478 if (writecounted)
2479 vnode_pager_release_writecount(object, 0, size);
2480 vm_object_deallocate(object);
2481 }
2482 #ifdef HWPMC_HOOKS
2483 /* Inform hwpmc(4) if an executable is being mapped. */
2484 if (PMC_HOOK_INSTALLED(PMC_FN_MMAP)) {
2485 if ((prot & VM_PROT_EXECUTE) != 0 && error == 0) {
2486 pkm.pm_file = vp;
2487 pkm.pm_address = (uintptr_t) *addr;
2488 PMC_CALL_HOOK(td, PMC_FN_MMAP, (void *) &pkm);
2489 }
2490 }
2491 #endif
2492 return (error);
2493 }
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