1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Copyright (c) 2012 Konstantin Belousov <[email protected]>
13 * Copyright (c) 2013, 2014 The FreeBSD Foundation
14 *
15 * Portions of this software were developed by Konstantin Belousov
16 * under sponsorship from the FreeBSD Foundation.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
20 * are met:
21 * 1. Redistributions of source code must retain the above copyright
22 * notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 * notice, this list of conditions and the following disclaimer in the
25 * documentation and/or other materials provided with the distribution.
26 * 3. Neither the name of the University nor the names of its contributors
27 * may be used to endorse or promote products derived from this software
28 * without specific prior written permission.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
40 * SUCH DAMAGE.
41 *
42 * @(#)vfs_vnops.c 8.2 (Berkeley) 1/21/94
43 */
44
45 #include <sys/cdefs.h>
46 __FBSDID("$FreeBSD$");
47
48 #include "opt_hwpmc_hooks.h"
49
50 #include <sys/param.h>
51 #include <sys/systm.h>
52 #include <sys/disk.h>
53 #include <sys/fail.h>
54 #include <sys/fcntl.h>
55 #include <sys/file.h>
56 #include <sys/kdb.h>
57 #include <sys/ktr.h>
58 #include <sys/stat.h>
59 #include <sys/priv.h>
60 #include <sys/proc.h>
61 #include <sys/limits.h>
62 #include <sys/lock.h>
63 #include <sys/mman.h>
64 #include <sys/mount.h>
65 #include <sys/mutex.h>
66 #include <sys/namei.h>
67 #include <sys/vnode.h>
68 #include <sys/bio.h>
69 #include <sys/buf.h>
70 #include <sys/filio.h>
71 #include <sys/resourcevar.h>
72 #include <sys/rwlock.h>
73 #include <sys/prng.h>
74 #include <sys/sx.h>
75 #include <sys/sleepqueue.h>
76 #include <sys/sysctl.h>
77 #include <sys/ttycom.h>
78 #include <sys/conf.h>
79 #include <sys/syslog.h>
80 #include <sys/unistd.h>
81 #include <sys/user.h>
82
83 #include <security/audit/audit.h>
84 #include <security/mac/mac_framework.h>
85
86 #include <vm/vm.h>
87 #include <vm/vm_extern.h>
88 #include <vm/pmap.h>
89 #include <vm/vm_map.h>
90 #include <vm/vm_object.h>
91 #include <vm/vm_page.h>
92 #include <vm/vm_pager.h>
93
94 #ifdef HWPMC_HOOKS
95 #include <sys/pmckern.h>
96 #endif
97
98 static fo_rdwr_t vn_read;
99 static fo_rdwr_t vn_write;
100 static fo_rdwr_t vn_io_fault;
101 static fo_truncate_t vn_truncate;
102 static fo_ioctl_t vn_ioctl;
103 static fo_poll_t vn_poll;
104 static fo_kqfilter_t vn_kqfilter;
105 static fo_stat_t vn_statfile;
106 static fo_close_t vn_closefile;
107 static fo_mmap_t vn_mmap;
108 static fo_fallocate_t vn_fallocate;
109
110 struct fileops vnops = {
111 .fo_read = vn_io_fault,
112 .fo_write = vn_io_fault,
113 .fo_truncate = vn_truncate,
114 .fo_ioctl = vn_ioctl,
115 .fo_poll = vn_poll,
116 .fo_kqfilter = vn_kqfilter,
117 .fo_stat = vn_statfile,
118 .fo_close = vn_closefile,
119 .fo_chmod = vn_chmod,
120 .fo_chown = vn_chown,
121 .fo_sendfile = vn_sendfile,
122 .fo_seek = vn_seek,
123 .fo_fill_kinfo = vn_fill_kinfo,
124 .fo_mmap = vn_mmap,
125 .fo_fallocate = vn_fallocate,
126 .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE
127 };
128
129 const u_int io_hold_cnt = 16;
130 static int vn_io_fault_enable = 1;
131 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RWTUN,
132 &vn_io_fault_enable, 0, "Enable vn_io_fault lock avoidance");
133 static int vn_io_fault_prefault = 0;
134 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_prefault, CTLFLAG_RWTUN,
135 &vn_io_fault_prefault, 0, "Enable vn_io_fault prefaulting");
136 static int vn_io_pgcache_read_enable = 1;
137 SYSCTL_INT(_debug, OID_AUTO, vn_io_pgcache_read_enable, CTLFLAG_RWTUN,
138 &vn_io_pgcache_read_enable, 0,
139 "Enable copying from page cache for reads, avoiding fs");
140 static u_long vn_io_faults_cnt;
141 SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD,
142 &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers");
143
144 static int vfs_allow_read_dir = 0;
145 SYSCTL_INT(_security_bsd, OID_AUTO, allow_read_dir, CTLFLAG_RW,
146 &vfs_allow_read_dir, 0,
147 "Enable read(2) of directory by root for filesystems that support it");
148
149 /*
150 * Returns true if vn_io_fault mode of handling the i/o request should
151 * be used.
152 */
153 static bool
do_vn_io_fault(struct vnode * vp,struct uio * uio)154 do_vn_io_fault(struct vnode *vp, struct uio *uio)
155 {
156 struct mount *mp;
157
158 return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG &&
159 (mp = vp->v_mount) != NULL &&
160 (mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable);
161 }
162
163 /*
164 * Structure used to pass arguments to vn_io_fault1(), to do either
165 * file- or vnode-based I/O calls.
166 */
167 struct vn_io_fault_args {
168 enum {
169 VN_IO_FAULT_FOP,
170 VN_IO_FAULT_VOP
171 } kind;
172 struct ucred *cred;
173 int flags;
174 union {
175 struct fop_args_tag {
176 struct file *fp;
177 fo_rdwr_t *doio;
178 } fop_args;
179 struct vop_args_tag {
180 struct vnode *vp;
181 } vop_args;
182 } args;
183 };
184
185 static int vn_io_fault1(struct vnode *vp, struct uio *uio,
186 struct vn_io_fault_args *args, struct thread *td);
187
188 int
vn_open(struct nameidata * ndp,int * flagp,int cmode,struct file * fp)189 vn_open(struct nameidata *ndp, int *flagp, int cmode, struct file *fp)
190 {
191 struct thread *td = ndp->ni_cnd.cn_thread;
192
193 return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp));
194 }
195
196 static uint64_t
open2nameif(int fmode,u_int vn_open_flags)197 open2nameif(int fmode, u_int vn_open_flags)
198 {
199 uint64_t res;
200
201 res = ISOPEN | LOCKLEAF;
202 if ((fmode & O_RESOLVE_BENEATH) != 0)
203 res |= RBENEATH;
204 if ((vn_open_flags & VN_OPEN_NOAUDIT) == 0)
205 res |= AUDITVNODE1;
206 if ((vn_open_flags & VN_OPEN_NOCAPCHECK) != 0)
207 res |= NOCAPCHECK;
208 return (res);
209 }
210
211 /*
212 * Common code for vnode open operations via a name lookup.
213 * Lookup the vnode and invoke VOP_CREATE if needed.
214 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine.
215 *
216 * Note that this does NOT free nameidata for the successful case,
217 * due to the NDINIT being done elsewhere.
218 */
219 int
vn_open_cred(struct nameidata * ndp,int * flagp,int cmode,u_int vn_open_flags,struct ucred * cred,struct file * fp)220 vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags,
221 struct ucred *cred, struct file *fp)
222 {
223 struct vnode *vp;
224 struct mount *mp;
225 struct thread *td = ndp->ni_cnd.cn_thread;
226 struct vattr vat;
227 struct vattr *vap = &vat;
228 int fmode, error;
229
230 restart:
231 fmode = *flagp;
232 if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT |
233 O_EXCL | O_DIRECTORY))
234 return (EINVAL);
235 else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) {
236 ndp->ni_cnd.cn_nameiop = CREATE;
237 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags);
238 /*
239 * Set NOCACHE to avoid flushing the cache when
240 * rolling in many files at once.
241 *
242 * Set NC_KEEPPOSENTRY to keep positive entries if they already
243 * exist despite NOCACHE.
244 */
245 ndp->ni_cnd.cn_flags |= LOCKPARENT | NOCACHE | NC_KEEPPOSENTRY;
246 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0)
247 ndp->ni_cnd.cn_flags |= FOLLOW;
248 if ((vn_open_flags & VN_OPEN_INVFS) == 0)
249 bwillwrite();
250 if ((error = namei(ndp)) != 0)
251 return (error);
252 if (ndp->ni_vp == NULL) {
253 VATTR_NULL(vap);
254 vap->va_type = VREG;
255 vap->va_mode = cmode;
256 if (fmode & O_EXCL)
257 vap->va_vaflags |= VA_EXCLUSIVE;
258 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) {
259 NDFREE(ndp, NDF_ONLY_PNBUF);
260 vput(ndp->ni_dvp);
261 if ((error = vn_start_write(NULL, &mp,
262 V_XSLEEP | PCATCH)) != 0)
263 return (error);
264 NDREINIT(ndp);
265 goto restart;
266 }
267 if ((vn_open_flags & VN_OPEN_NAMECACHE) != 0)
268 ndp->ni_cnd.cn_flags |= MAKEENTRY;
269 #ifdef MAC
270 error = mac_vnode_check_create(cred, ndp->ni_dvp,
271 &ndp->ni_cnd, vap);
272 if (error == 0)
273 #endif
274 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp,
275 &ndp->ni_cnd, vap);
276 VOP_VPUT_PAIR(ndp->ni_dvp, error == 0 ? &ndp->ni_vp :
277 NULL, false);
278 vn_finished_write(mp);
279 if (error) {
280 NDFREE(ndp, NDF_ONLY_PNBUF);
281 if (error == ERELOOKUP) {
282 NDREINIT(ndp);
283 goto restart;
284 }
285 return (error);
286 }
287 fmode &= ~O_TRUNC;
288 vp = ndp->ni_vp;
289 } else {
290 if (ndp->ni_dvp == ndp->ni_vp)
291 vrele(ndp->ni_dvp);
292 else
293 vput(ndp->ni_dvp);
294 ndp->ni_dvp = NULL;
295 vp = ndp->ni_vp;
296 if (fmode & O_EXCL) {
297 error = EEXIST;
298 goto bad;
299 }
300 if (vp->v_type == VDIR) {
301 error = EISDIR;
302 goto bad;
303 }
304 fmode &= ~O_CREAT;
305 }
306 } else {
307 ndp->ni_cnd.cn_nameiop = LOOKUP;
308 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags);
309 ndp->ni_cnd.cn_flags |= (fmode & O_NOFOLLOW) != 0 ? NOFOLLOW :
310 FOLLOW;
311 if ((fmode & FWRITE) == 0)
312 ndp->ni_cnd.cn_flags |= LOCKSHARED;
313 if ((error = namei(ndp)) != 0)
314 return (error);
315 vp = ndp->ni_vp;
316 }
317 error = vn_open_vnode(vp, fmode, cred, td, fp);
318 if (error)
319 goto bad;
320 *flagp = fmode;
321 return (0);
322 bad:
323 NDFREE(ndp, NDF_ONLY_PNBUF);
324 vput(vp);
325 *flagp = fmode;
326 ndp->ni_vp = NULL;
327 return (error);
328 }
329
330 static int
vn_open_vnode_advlock(struct vnode * vp,int fmode,struct file * fp)331 vn_open_vnode_advlock(struct vnode *vp, int fmode, struct file *fp)
332 {
333 struct flock lf;
334 int error, lock_flags, type;
335
336 ASSERT_VOP_LOCKED(vp, "vn_open_vnode_advlock");
337 if ((fmode & (O_EXLOCK | O_SHLOCK)) == 0)
338 return (0);
339 KASSERT(fp != NULL, ("open with flock requires fp"));
340 if (fp->f_type != DTYPE_NONE && fp->f_type != DTYPE_VNODE)
341 return (EOPNOTSUPP);
342
343 lock_flags = VOP_ISLOCKED(vp);
344 VOP_UNLOCK(vp);
345
346 lf.l_whence = SEEK_SET;
347 lf.l_start = 0;
348 lf.l_len = 0;
349 lf.l_type = (fmode & O_EXLOCK) != 0 ? F_WRLCK : F_RDLCK;
350 type = F_FLOCK;
351 if ((fmode & FNONBLOCK) == 0)
352 type |= F_WAIT;
353 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type);
354 if (error == 0)
355 fp->f_flag |= FHASLOCK;
356
357 vn_lock(vp, lock_flags | LK_RETRY);
358 return (error);
359 }
360
361 /*
362 * Common code for vnode open operations once a vnode is located.
363 * Check permissions, and call the VOP_OPEN routine.
364 */
365 int
vn_open_vnode(struct vnode * vp,int fmode,struct ucred * cred,struct thread * td,struct file * fp)366 vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred,
367 struct thread *td, struct file *fp)
368 {
369 accmode_t accmode;
370 int error;
371
372 if (vp->v_type == VLNK)
373 return (EMLINK);
374 if (vp->v_type == VSOCK)
375 return (EOPNOTSUPP);
376 if (vp->v_type != VDIR && fmode & O_DIRECTORY)
377 return (ENOTDIR);
378 accmode = 0;
379 if (fmode & (FWRITE | O_TRUNC)) {
380 if (vp->v_type == VDIR)
381 return (EISDIR);
382 accmode |= VWRITE;
383 }
384 if (fmode & FREAD)
385 accmode |= VREAD;
386 if (fmode & FEXEC)
387 accmode |= VEXEC;
388 if ((fmode & O_APPEND) && (fmode & FWRITE))
389 accmode |= VAPPEND;
390 #ifdef MAC
391 if (fmode & O_CREAT)
392 accmode |= VCREAT;
393 if (fmode & O_VERIFY)
394 accmode |= VVERIFY;
395 error = mac_vnode_check_open(cred, vp, accmode);
396 if (error)
397 return (error);
398
399 accmode &= ~(VCREAT | VVERIFY);
400 #endif
401 if ((fmode & O_CREAT) == 0 && accmode != 0) {
402 error = VOP_ACCESS(vp, accmode, cred, td);
403 if (error != 0)
404 return (error);
405 }
406 if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
407 vn_lock(vp, LK_UPGRADE | LK_RETRY);
408 error = VOP_OPEN(vp, fmode, cred, td, fp);
409 if (error != 0)
410 return (error);
411
412 error = vn_open_vnode_advlock(vp, fmode, fp);
413 if (error == 0 && (fmode & FWRITE) != 0) {
414 error = VOP_ADD_WRITECOUNT(vp, 1);
415 if (error == 0) {
416 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d",
417 __func__, vp, vp->v_writecount);
418 }
419 }
420
421 /*
422 * Error from advlock or VOP_ADD_WRITECOUNT() still requires
423 * calling VOP_CLOSE() to pair with earlier VOP_OPEN().
424 * Arrange for that by having fdrop() to use vn_closefile().
425 */
426 if (error != 0) {
427 fp->f_flag |= FOPENFAILED;
428 fp->f_vnode = vp;
429 if (fp->f_ops == &badfileops) {
430 fp->f_type = DTYPE_VNODE;
431 fp->f_ops = &vnops;
432 }
433 vref(vp);
434 }
435
436 ASSERT_VOP_LOCKED(vp, "vn_open_vnode");
437 return (error);
438
439 }
440
441 /*
442 * Check for write permissions on the specified vnode.
443 * Prototype text segments cannot be written.
444 * It is racy.
445 */
446 int
vn_writechk(struct vnode * vp)447 vn_writechk(struct vnode *vp)
448 {
449
450 ASSERT_VOP_LOCKED(vp, "vn_writechk");
451 /*
452 * If there's shared text associated with
453 * the vnode, try to free it up once. If
454 * we fail, we can't allow writing.
455 */
456 if (VOP_IS_TEXT(vp))
457 return (ETXTBSY);
458
459 return (0);
460 }
461
462 /*
463 * Vnode close call
464 */
465 static int
vn_close1(struct vnode * vp,int flags,struct ucred * file_cred,struct thread * td,bool keep_ref)466 vn_close1(struct vnode *vp, int flags, struct ucred *file_cred,
467 struct thread *td, bool keep_ref)
468 {
469 struct mount *mp;
470 int error, lock_flags;
471
472 if (vp->v_type != VFIFO && (flags & FWRITE) == 0 &&
473 MNT_EXTENDED_SHARED(vp->v_mount))
474 lock_flags = LK_SHARED;
475 else
476 lock_flags = LK_EXCLUSIVE;
477
478 vn_start_write(vp, &mp, V_WAIT);
479 vn_lock(vp, lock_flags | LK_RETRY);
480 AUDIT_ARG_VNODE1(vp);
481 if ((flags & (FWRITE | FOPENFAILED)) == FWRITE) {
482 VOP_ADD_WRITECOUNT_CHECKED(vp, -1);
483 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
484 __func__, vp, vp->v_writecount);
485 }
486 error = VOP_CLOSE(vp, flags, file_cred, td);
487 if (keep_ref)
488 VOP_UNLOCK(vp);
489 else
490 vput(vp);
491 vn_finished_write(mp);
492 return (error);
493 }
494
495 int
vn_close(struct vnode * vp,int flags,struct ucred * file_cred,struct thread * td)496 vn_close(struct vnode *vp, int flags, struct ucred *file_cred,
497 struct thread *td)
498 {
499
500 return (vn_close1(vp, flags, file_cred, td, false));
501 }
502
503 /*
504 * Heuristic to detect sequential operation.
505 */
506 static int
sequential_heuristic(struct uio * uio,struct file * fp)507 sequential_heuristic(struct uio *uio, struct file *fp)
508 {
509 enum uio_rw rw;
510
511 ASSERT_VOP_LOCKED(fp->f_vnode, __func__);
512
513 rw = uio->uio_rw;
514 if (fp->f_flag & FRDAHEAD)
515 return (fp->f_seqcount[rw] << IO_SEQSHIFT);
516
517 /*
518 * Offset 0 is handled specially. open() sets f_seqcount to 1 so
519 * that the first I/O is normally considered to be slightly
520 * sequential. Seeking to offset 0 doesn't change sequentiality
521 * unless previous seeks have reduced f_seqcount to 0, in which
522 * case offset 0 is not special.
523 */
524 if ((uio->uio_offset == 0 && fp->f_seqcount[rw] > 0) ||
525 uio->uio_offset == fp->f_nextoff[rw]) {
526 /*
527 * f_seqcount is in units of fixed-size blocks so that it
528 * depends mainly on the amount of sequential I/O and not
529 * much on the number of sequential I/O's. The fixed size
530 * of 16384 is hard-coded here since it is (not quite) just
531 * a magic size that works well here. This size is more
532 * closely related to the best I/O size for real disks than
533 * to any block size used by software.
534 */
535 if (uio->uio_resid >= IO_SEQMAX * 16384)
536 fp->f_seqcount[rw] = IO_SEQMAX;
537 else {
538 fp->f_seqcount[rw] += howmany(uio->uio_resid, 16384);
539 if (fp->f_seqcount[rw] > IO_SEQMAX)
540 fp->f_seqcount[rw] = IO_SEQMAX;
541 }
542 return (fp->f_seqcount[rw] << IO_SEQSHIFT);
543 }
544
545 /* Not sequential. Quickly draw-down sequentiality. */
546 if (fp->f_seqcount[rw] > 1)
547 fp->f_seqcount[rw] = 1;
548 else
549 fp->f_seqcount[rw] = 0;
550 return (0);
551 }
552
553 /*
554 * Package up an I/O request on a vnode into a uio and do it.
555 */
556 int
vn_rdwr(enum uio_rw rw,struct vnode * vp,void * base,int len,off_t offset,enum uio_seg segflg,int ioflg,struct ucred * active_cred,struct ucred * file_cred,ssize_t * aresid,struct thread * td)557 vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset,
558 enum uio_seg segflg, int ioflg, struct ucred *active_cred,
559 struct ucred *file_cred, ssize_t *aresid, struct thread *td)
560 {
561 struct uio auio;
562 struct iovec aiov;
563 struct mount *mp;
564 struct ucred *cred;
565 void *rl_cookie;
566 struct vn_io_fault_args args;
567 int error, lock_flags;
568
569 if (offset < 0 && vp->v_type != VCHR)
570 return (EINVAL);
571 auio.uio_iov = &aiov;
572 auio.uio_iovcnt = 1;
573 aiov.iov_base = base;
574 aiov.iov_len = len;
575 auio.uio_resid = len;
576 auio.uio_offset = offset;
577 auio.uio_segflg = segflg;
578 auio.uio_rw = rw;
579 auio.uio_td = td;
580 error = 0;
581
582 if ((ioflg & IO_NODELOCKED) == 0) {
583 if ((ioflg & IO_RANGELOCKED) == 0) {
584 if (rw == UIO_READ) {
585 rl_cookie = vn_rangelock_rlock(vp, offset,
586 offset + len);
587 } else if ((ioflg & IO_APPEND) != 0) {
588 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
589 } else {
590 rl_cookie = vn_rangelock_wlock(vp, offset,
591 offset + len);
592 }
593 } else
594 rl_cookie = NULL;
595 mp = NULL;
596 if (rw == UIO_WRITE) {
597 if (vp->v_type != VCHR &&
598 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH))
599 != 0)
600 goto out;
601 if (MNT_SHARED_WRITES(mp) ||
602 ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount)))
603 lock_flags = LK_SHARED;
604 else
605 lock_flags = LK_EXCLUSIVE;
606 } else
607 lock_flags = LK_SHARED;
608 vn_lock(vp, lock_flags | LK_RETRY);
609 } else
610 rl_cookie = NULL;
611
612 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
613 #ifdef MAC
614 if ((ioflg & IO_NOMACCHECK) == 0) {
615 if (rw == UIO_READ)
616 error = mac_vnode_check_read(active_cred, file_cred,
617 vp);
618 else
619 error = mac_vnode_check_write(active_cred, file_cred,
620 vp);
621 }
622 #endif
623 if (error == 0) {
624 if (file_cred != NULL)
625 cred = file_cred;
626 else
627 cred = active_cred;
628 if (do_vn_io_fault(vp, &auio)) {
629 args.kind = VN_IO_FAULT_VOP;
630 args.cred = cred;
631 args.flags = ioflg;
632 args.args.vop_args.vp = vp;
633 error = vn_io_fault1(vp, &auio, &args, td);
634 } else if (rw == UIO_READ) {
635 error = VOP_READ(vp, &auio, ioflg, cred);
636 } else /* if (rw == UIO_WRITE) */ {
637 error = VOP_WRITE(vp, &auio, ioflg, cred);
638 }
639 }
640 if (aresid)
641 *aresid = auio.uio_resid;
642 else
643 if (auio.uio_resid && error == 0)
644 error = EIO;
645 if ((ioflg & IO_NODELOCKED) == 0) {
646 VOP_UNLOCK(vp);
647 if (mp != NULL)
648 vn_finished_write(mp);
649 }
650 out:
651 if (rl_cookie != NULL)
652 vn_rangelock_unlock(vp, rl_cookie);
653 return (error);
654 }
655
656 /*
657 * Package up an I/O request on a vnode into a uio and do it. The I/O
658 * request is split up into smaller chunks and we try to avoid saturating
659 * the buffer cache while potentially holding a vnode locked, so we
660 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield()
661 * to give other processes a chance to lock the vnode (either other processes
662 * core'ing the same binary, or unrelated processes scanning the directory).
663 */
664 int
vn_rdwr_inchunks(enum uio_rw rw,struct vnode * vp,void * base,size_t len,off_t offset,enum uio_seg segflg,int ioflg,struct ucred * active_cred,struct ucred * file_cred,size_t * aresid,struct thread * td)665 vn_rdwr_inchunks(enum uio_rw rw, struct vnode *vp, void *base, size_t len,
666 off_t offset, enum uio_seg segflg, int ioflg, struct ucred *active_cred,
667 struct ucred *file_cred, size_t *aresid, struct thread *td)
668 {
669 int error = 0;
670 ssize_t iaresid;
671
672 do {
673 int chunk;
674
675 /*
676 * Force `offset' to a multiple of MAXBSIZE except possibly
677 * for the first chunk, so that filesystems only need to
678 * write full blocks except possibly for the first and last
679 * chunks.
680 */
681 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE;
682
683 if (chunk > len)
684 chunk = len;
685 if (rw != UIO_READ && vp->v_type == VREG)
686 bwillwrite();
687 iaresid = 0;
688 error = vn_rdwr(rw, vp, base, chunk, offset, segflg,
689 ioflg, active_cred, file_cred, &iaresid, td);
690 len -= chunk; /* aresid calc already includes length */
691 if (error)
692 break;
693 offset += chunk;
694 base = (char *)base + chunk;
695 kern_yield(PRI_USER);
696 } while (len);
697 if (aresid)
698 *aresid = len + iaresid;
699 return (error);
700 }
701
702 #if OFF_MAX <= LONG_MAX
703 off_t
foffset_lock(struct file * fp,int flags)704 foffset_lock(struct file *fp, int flags)
705 {
706 volatile short *flagsp;
707 off_t res;
708 short state;
709
710 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
711
712 if ((flags & FOF_NOLOCK) != 0)
713 return (atomic_load_long(&fp->f_offset));
714
715 /*
716 * According to McKusick the vn lock was protecting f_offset here.
717 * It is now protected by the FOFFSET_LOCKED flag.
718 */
719 flagsp = &fp->f_vnread_flags;
720 if (atomic_cmpset_acq_16(flagsp, 0, FOFFSET_LOCKED))
721 return (atomic_load_long(&fp->f_offset));
722
723 sleepq_lock(&fp->f_vnread_flags);
724 state = atomic_load_16(flagsp);
725 for (;;) {
726 if ((state & FOFFSET_LOCKED) == 0) {
727 if (!atomic_fcmpset_acq_16(flagsp, &state,
728 FOFFSET_LOCKED))
729 continue;
730 break;
731 }
732 if ((state & FOFFSET_LOCK_WAITING) == 0) {
733 if (!atomic_fcmpset_acq_16(flagsp, &state,
734 state | FOFFSET_LOCK_WAITING))
735 continue;
736 }
737 DROP_GIANT();
738 sleepq_add(&fp->f_vnread_flags, NULL, "vofflock", 0, 0);
739 sleepq_wait(&fp->f_vnread_flags, PUSER -1);
740 PICKUP_GIANT();
741 sleepq_lock(&fp->f_vnread_flags);
742 state = atomic_load_16(flagsp);
743 }
744 res = atomic_load_long(&fp->f_offset);
745 sleepq_release(&fp->f_vnread_flags);
746 return (res);
747 }
748
749 void
foffset_unlock(struct file * fp,off_t val,int flags)750 foffset_unlock(struct file *fp, off_t val, int flags)
751 {
752 volatile short *flagsp;
753 short state;
754
755 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
756
757 if ((flags & FOF_NOUPDATE) == 0)
758 atomic_store_long(&fp->f_offset, val);
759 if ((flags & FOF_NEXTOFF_R) != 0)
760 fp->f_nextoff[UIO_READ] = val;
761 if ((flags & FOF_NEXTOFF_W) != 0)
762 fp->f_nextoff[UIO_WRITE] = val;
763
764 if ((flags & FOF_NOLOCK) != 0)
765 return;
766
767 flagsp = &fp->f_vnread_flags;
768 state = atomic_load_16(flagsp);
769 if ((state & FOFFSET_LOCK_WAITING) == 0 &&
770 atomic_cmpset_rel_16(flagsp, state, 0))
771 return;
772
773 sleepq_lock(&fp->f_vnread_flags);
774 MPASS((fp->f_vnread_flags & FOFFSET_LOCKED) != 0);
775 MPASS((fp->f_vnread_flags & FOFFSET_LOCK_WAITING) != 0);
776 fp->f_vnread_flags = 0;
777 sleepq_broadcast(&fp->f_vnread_flags, SLEEPQ_SLEEP, 0, 0);
778 sleepq_release(&fp->f_vnread_flags);
779 }
780 #else
781 off_t
foffset_lock(struct file * fp,int flags)782 foffset_lock(struct file *fp, int flags)
783 {
784 struct mtx *mtxp;
785 off_t res;
786
787 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
788
789 mtxp = mtx_pool_find(mtxpool_sleep, fp);
790 mtx_lock(mtxp);
791 if ((flags & FOF_NOLOCK) == 0) {
792 while (fp->f_vnread_flags & FOFFSET_LOCKED) {
793 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING;
794 msleep(&fp->f_vnread_flags, mtxp, PUSER -1,
795 "vofflock", 0);
796 }
797 fp->f_vnread_flags |= FOFFSET_LOCKED;
798 }
799 res = fp->f_offset;
800 mtx_unlock(mtxp);
801 return (res);
802 }
803
804 void
foffset_unlock(struct file * fp,off_t val,int flags)805 foffset_unlock(struct file *fp, off_t val, int flags)
806 {
807 struct mtx *mtxp;
808
809 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
810
811 mtxp = mtx_pool_find(mtxpool_sleep, fp);
812 mtx_lock(mtxp);
813 if ((flags & FOF_NOUPDATE) == 0)
814 fp->f_offset = val;
815 if ((flags & FOF_NEXTOFF_R) != 0)
816 fp->f_nextoff[UIO_READ] = val;
817 if ((flags & FOF_NEXTOFF_W) != 0)
818 fp->f_nextoff[UIO_WRITE] = val;
819 if ((flags & FOF_NOLOCK) == 0) {
820 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0,
821 ("Lost FOFFSET_LOCKED"));
822 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING)
823 wakeup(&fp->f_vnread_flags);
824 fp->f_vnread_flags = 0;
825 }
826 mtx_unlock(mtxp);
827 }
828 #endif
829
830 void
foffset_lock_uio(struct file * fp,struct uio * uio,int flags)831 foffset_lock_uio(struct file *fp, struct uio *uio, int flags)
832 {
833
834 if ((flags & FOF_OFFSET) == 0)
835 uio->uio_offset = foffset_lock(fp, flags);
836 }
837
838 void
foffset_unlock_uio(struct file * fp,struct uio * uio,int flags)839 foffset_unlock_uio(struct file *fp, struct uio *uio, int flags)
840 {
841
842 if ((flags & FOF_OFFSET) == 0)
843 foffset_unlock(fp, uio->uio_offset, flags);
844 }
845
846 static int
get_advice(struct file * fp,struct uio * uio)847 get_advice(struct file *fp, struct uio *uio)
848 {
849 struct mtx *mtxp;
850 int ret;
851
852 ret = POSIX_FADV_NORMAL;
853 if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG)
854 return (ret);
855
856 mtxp = mtx_pool_find(mtxpool_sleep, fp);
857 mtx_lock(mtxp);
858 if (fp->f_advice != NULL &&
859 uio->uio_offset >= fp->f_advice->fa_start &&
860 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end)
861 ret = fp->f_advice->fa_advice;
862 mtx_unlock(mtxp);
863 return (ret);
864 }
865
866 int
vn_read_from_obj(struct vnode * vp,struct uio * uio)867 vn_read_from_obj(struct vnode *vp, struct uio *uio)
868 {
869 vm_object_t obj;
870 vm_page_t ma[io_hold_cnt + 2];
871 off_t off, vsz;
872 ssize_t resid;
873 int error, i, j;
874
875 MPASS(uio->uio_resid <= ptoa(io_hold_cnt + 2));
876 obj = atomic_load_ptr(&vp->v_object);
877 if (obj == NULL)
878 return (EJUSTRETURN);
879
880 /*
881 * Depends on type stability of vm_objects.
882 */
883 vm_object_pip_add(obj, 1);
884 if ((obj->flags & OBJ_DEAD) != 0) {
885 /*
886 * Note that object might be already reused from the
887 * vnode, and the OBJ_DEAD flag cleared. This is fine,
888 * we recheck for DOOMED vnode state after all pages
889 * are busied, and retract then.
890 *
891 * But we check for OBJ_DEAD to ensure that we do not
892 * busy pages while vm_object_terminate_pages()
893 * processes the queue.
894 */
895 error = EJUSTRETURN;
896 goto out_pip;
897 }
898
899 resid = uio->uio_resid;
900 off = uio->uio_offset;
901 for (i = 0; resid > 0; i++) {
902 MPASS(i < io_hold_cnt + 2);
903 ma[i] = vm_page_grab_unlocked(obj, atop(off),
904 VM_ALLOC_NOCREAT | VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY |
905 VM_ALLOC_NOWAIT);
906 if (ma[i] == NULL)
907 break;
908
909 /*
910 * Skip invalid pages. Valid mask can be partial only
911 * at EOF, and we clip later.
912 */
913 if (vm_page_none_valid(ma[i])) {
914 vm_page_sunbusy(ma[i]);
915 break;
916 }
917
918 resid -= PAGE_SIZE;
919 off += PAGE_SIZE;
920 }
921 if (i == 0) {
922 error = EJUSTRETURN;
923 goto out_pip;
924 }
925
926 /*
927 * Check VIRF_DOOMED after we busied our pages. Since
928 * vgonel() terminates the vnode' vm_object, it cannot
929 * process past pages busied by us.
930 */
931 if (VN_IS_DOOMED(vp)) {
932 error = EJUSTRETURN;
933 goto out;
934 }
935
936 resid = PAGE_SIZE - (uio->uio_offset & PAGE_MASK) + ptoa(i - 1);
937 if (resid > uio->uio_resid)
938 resid = uio->uio_resid;
939
940 /*
941 * Unlocked read of vnp_size is safe because truncation cannot
942 * pass busied page. But we load vnp_size into a local
943 * variable so that possible concurrent extension does not
944 * break calculation.
945 */
946 #if defined(__powerpc__) && !defined(__powerpc64__)
947 vsz = obj->un_pager.vnp.vnp_size;
948 #else
949 vsz = atomic_load_64(&obj->un_pager.vnp.vnp_size);
950 #endif
951 if (uio->uio_offset >= vsz) {
952 error = EJUSTRETURN;
953 goto out;
954 }
955 if (uio->uio_offset + resid > vsz)
956 resid = vsz - uio->uio_offset;
957
958 error = vn_io_fault_pgmove(ma, uio->uio_offset & PAGE_MASK, resid, uio);
959
960 out:
961 for (j = 0; j < i; j++) {
962 if (error == 0)
963 vm_page_reference(ma[j]);
964 vm_page_sunbusy(ma[j]);
965 }
966 out_pip:
967 vm_object_pip_wakeup(obj);
968 if (error != 0)
969 return (error);
970 return (uio->uio_resid == 0 ? 0 : EJUSTRETURN);
971 }
972
973 /*
974 * File table vnode read routine.
975 */
976 static int
vn_read(struct file * fp,struct uio * uio,struct ucred * active_cred,int flags,struct thread * td)977 vn_read(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags,
978 struct thread *td)
979 {
980 struct vnode *vp;
981 off_t orig_offset;
982 int error, ioflag;
983 int advice;
984
985 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
986 uio->uio_td, td));
987 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET"));
988 vp = fp->f_vnode;
989 ioflag = 0;
990 if (fp->f_flag & FNONBLOCK)
991 ioflag |= IO_NDELAY;
992 if (fp->f_flag & O_DIRECT)
993 ioflag |= IO_DIRECT;
994
995 /*
996 * Try to read from page cache. VIRF_DOOMED check is racy but
997 * allows us to avoid unneeded work outright.
998 */
999 if (vn_io_pgcache_read_enable && !mac_vnode_check_read_enabled() &&
1000 (vn_irflag_read(vp) & (VIRF_DOOMED | VIRF_PGREAD)) == VIRF_PGREAD) {
1001 error = VOP_READ_PGCACHE(vp, uio, ioflag, fp->f_cred);
1002 if (error == 0) {
1003 fp->f_nextoff[UIO_READ] = uio->uio_offset;
1004 return (0);
1005 }
1006 if (error != EJUSTRETURN)
1007 return (error);
1008 }
1009
1010 advice = get_advice(fp, uio);
1011 vn_lock(vp, LK_SHARED | LK_RETRY);
1012
1013 switch (advice) {
1014 case POSIX_FADV_NORMAL:
1015 case POSIX_FADV_SEQUENTIAL:
1016 case POSIX_FADV_NOREUSE:
1017 ioflag |= sequential_heuristic(uio, fp);
1018 break;
1019 case POSIX_FADV_RANDOM:
1020 /* Disable read-ahead for random I/O. */
1021 break;
1022 }
1023 orig_offset = uio->uio_offset;
1024
1025 #ifdef MAC
1026 error = mac_vnode_check_read(active_cred, fp->f_cred, vp);
1027 if (error == 0)
1028 #endif
1029 error = VOP_READ(vp, uio, ioflag, fp->f_cred);
1030 fp->f_nextoff[UIO_READ] = uio->uio_offset;
1031 VOP_UNLOCK(vp);
1032 if (error == 0 && advice == POSIX_FADV_NOREUSE &&
1033 orig_offset != uio->uio_offset)
1034 /*
1035 * Use POSIX_FADV_DONTNEED to flush pages and buffers
1036 * for the backing file after a POSIX_FADV_NOREUSE
1037 * read(2).
1038 */
1039 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1,
1040 POSIX_FADV_DONTNEED);
1041 return (error);
1042 }
1043
1044 /*
1045 * File table vnode write routine.
1046 */
1047 static int
vn_write(struct file * fp,struct uio * uio,struct ucred * active_cred,int flags,struct thread * td)1048 vn_write(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags,
1049 struct thread *td)
1050 {
1051 struct vnode *vp;
1052 struct mount *mp;
1053 off_t orig_offset;
1054 int error, ioflag, lock_flags;
1055 int advice;
1056
1057 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
1058 uio->uio_td, td));
1059 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET"));
1060 vp = fp->f_vnode;
1061 if (vp->v_type == VREG)
1062 bwillwrite();
1063 ioflag = IO_UNIT;
1064 if (vp->v_type == VREG && (fp->f_flag & O_APPEND))
1065 ioflag |= IO_APPEND;
1066 if (fp->f_flag & FNONBLOCK)
1067 ioflag |= IO_NDELAY;
1068 if (fp->f_flag & O_DIRECT)
1069 ioflag |= IO_DIRECT;
1070 if ((fp->f_flag & O_FSYNC) ||
1071 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS)))
1072 ioflag |= IO_SYNC;
1073 /*
1074 * For O_DSYNC we set both IO_SYNC and IO_DATASYNC, so that VOP_WRITE()
1075 * implementations that don't understand IO_DATASYNC fall back to full
1076 * O_SYNC behavior.
1077 */
1078 if (fp->f_flag & O_DSYNC)
1079 ioflag |= IO_SYNC | IO_DATASYNC;
1080 mp = NULL;
1081 if (vp->v_type != VCHR &&
1082 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
1083 goto unlock;
1084
1085 advice = get_advice(fp, uio);
1086
1087 if (MNT_SHARED_WRITES(mp) ||
1088 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) {
1089 lock_flags = LK_SHARED;
1090 } else {
1091 lock_flags = LK_EXCLUSIVE;
1092 }
1093
1094 vn_lock(vp, lock_flags | LK_RETRY);
1095 switch (advice) {
1096 case POSIX_FADV_NORMAL:
1097 case POSIX_FADV_SEQUENTIAL:
1098 case POSIX_FADV_NOREUSE:
1099 ioflag |= sequential_heuristic(uio, fp);
1100 break;
1101 case POSIX_FADV_RANDOM:
1102 /* XXX: Is this correct? */
1103 break;
1104 }
1105 orig_offset = uio->uio_offset;
1106
1107 #ifdef MAC
1108 error = mac_vnode_check_write(active_cred, fp->f_cred, vp);
1109 if (error == 0)
1110 #endif
1111 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred);
1112 fp->f_nextoff[UIO_WRITE] = uio->uio_offset;
1113 VOP_UNLOCK(vp);
1114 if (vp->v_type != VCHR)
1115 vn_finished_write(mp);
1116 if (error == 0 && advice == POSIX_FADV_NOREUSE &&
1117 orig_offset != uio->uio_offset)
1118 /*
1119 * Use POSIX_FADV_DONTNEED to flush pages and buffers
1120 * for the backing file after a POSIX_FADV_NOREUSE
1121 * write(2).
1122 */
1123 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1,
1124 POSIX_FADV_DONTNEED);
1125 unlock:
1126 return (error);
1127 }
1128
1129 /*
1130 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to
1131 * prevent the following deadlock:
1132 *
1133 * Assume that the thread A reads from the vnode vp1 into userspace
1134 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is
1135 * currently not resident, then system ends up with the call chain
1136 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] ->
1137 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2)
1138 * which establishes lock order vp1->vn_lock, then vp2->vn_lock.
1139 * If, at the same time, thread B reads from vnode vp2 into buffer buf2
1140 * backed by the pages of vnode vp1, and some page in buf2 is not
1141 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock.
1142 *
1143 * To prevent the lock order reversal and deadlock, vn_io_fault() does
1144 * not allow page faults to happen during VOP_READ() or VOP_WRITE().
1145 * Instead, it first tries to do the whole range i/o with pagefaults
1146 * disabled. If all pages in the i/o buffer are resident and mapped,
1147 * VOP will succeed (ignoring the genuine filesystem errors).
1148 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do
1149 * i/o in chunks, with all pages in the chunk prefaulted and held
1150 * using vm_fault_quick_hold_pages().
1151 *
1152 * Filesystems using this deadlock avoidance scheme should use the
1153 * array of the held pages from uio, saved in the curthread->td_ma,
1154 * instead of doing uiomove(). A helper function
1155 * vn_io_fault_uiomove() converts uiomove request into
1156 * uiomove_fromphys() over td_ma array.
1157 *
1158 * Since vnode locks do not cover the whole i/o anymore, rangelocks
1159 * make the current i/o request atomic with respect to other i/os and
1160 * truncations.
1161 */
1162
1163 /*
1164 * Decode vn_io_fault_args and perform the corresponding i/o.
1165 */
1166 static int
vn_io_fault_doio(struct vn_io_fault_args * args,struct uio * uio,struct thread * td)1167 vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio,
1168 struct thread *td)
1169 {
1170 int error, save;
1171
1172 error = 0;
1173 save = vm_fault_disable_pagefaults();
1174 switch (args->kind) {
1175 case VN_IO_FAULT_FOP:
1176 error = (args->args.fop_args.doio)(args->args.fop_args.fp,
1177 uio, args->cred, args->flags, td);
1178 break;
1179 case VN_IO_FAULT_VOP:
1180 if (uio->uio_rw == UIO_READ) {
1181 error = VOP_READ(args->args.vop_args.vp, uio,
1182 args->flags, args->cred);
1183 } else if (uio->uio_rw == UIO_WRITE) {
1184 error = VOP_WRITE(args->args.vop_args.vp, uio,
1185 args->flags, args->cred);
1186 }
1187 break;
1188 default:
1189 panic("vn_io_fault_doio: unknown kind of io %d %d",
1190 args->kind, uio->uio_rw);
1191 }
1192 vm_fault_enable_pagefaults(save);
1193 return (error);
1194 }
1195
1196 static int
vn_io_fault_touch(char * base,const struct uio * uio)1197 vn_io_fault_touch(char *base, const struct uio *uio)
1198 {
1199 int r;
1200
1201 r = fubyte(base);
1202 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1))
1203 return (EFAULT);
1204 return (0);
1205 }
1206
1207 static int
vn_io_fault_prefault_user(const struct uio * uio)1208 vn_io_fault_prefault_user(const struct uio *uio)
1209 {
1210 char *base;
1211 const struct iovec *iov;
1212 size_t len;
1213 ssize_t resid;
1214 int error, i;
1215
1216 KASSERT(uio->uio_segflg == UIO_USERSPACE,
1217 ("vn_io_fault_prefault userspace"));
1218
1219 error = i = 0;
1220 iov = uio->uio_iov;
1221 resid = uio->uio_resid;
1222 base = iov->iov_base;
1223 len = iov->iov_len;
1224 while (resid > 0) {
1225 error = vn_io_fault_touch(base, uio);
1226 if (error != 0)
1227 break;
1228 if (len < PAGE_SIZE) {
1229 if (len != 0) {
1230 error = vn_io_fault_touch(base + len - 1, uio);
1231 if (error != 0)
1232 break;
1233 resid -= len;
1234 }
1235 if (++i >= uio->uio_iovcnt)
1236 break;
1237 iov = uio->uio_iov + i;
1238 base = iov->iov_base;
1239 len = iov->iov_len;
1240 } else {
1241 len -= PAGE_SIZE;
1242 base += PAGE_SIZE;
1243 resid -= PAGE_SIZE;
1244 }
1245 }
1246 return (error);
1247 }
1248
1249 /*
1250 * Common code for vn_io_fault(), agnostic to the kind of i/o request.
1251 * Uses vn_io_fault_doio() to make the call to an actual i/o function.
1252 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request
1253 * into args and call vn_io_fault1() to handle faults during the user
1254 * mode buffer accesses.
1255 */
1256 static int
vn_io_fault1(struct vnode * vp,struct uio * uio,struct vn_io_fault_args * args,struct thread * td)1257 vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args,
1258 struct thread *td)
1259 {
1260 vm_page_t ma[io_hold_cnt + 2];
1261 struct uio *uio_clone, short_uio;
1262 struct iovec short_iovec[1];
1263 vm_page_t *prev_td_ma;
1264 vm_prot_t prot;
1265 vm_offset_t addr, end;
1266 size_t len, resid;
1267 ssize_t adv;
1268 int error, cnt, saveheld, prev_td_ma_cnt;
1269
1270 if (vn_io_fault_prefault) {
1271 error = vn_io_fault_prefault_user(uio);
1272 if (error != 0)
1273 return (error); /* Or ignore ? */
1274 }
1275
1276 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ;
1277
1278 /*
1279 * The UFS follows IO_UNIT directive and replays back both
1280 * uio_offset and uio_resid if an error is encountered during the
1281 * operation. But, since the iovec may be already advanced,
1282 * uio is still in an inconsistent state.
1283 *
1284 * Cache a copy of the original uio, which is advanced to the redo
1285 * point using UIO_NOCOPY below.
1286 */
1287 uio_clone = cloneuio(uio);
1288 resid = uio->uio_resid;
1289
1290 short_uio.uio_segflg = UIO_USERSPACE;
1291 short_uio.uio_rw = uio->uio_rw;
1292 short_uio.uio_td = uio->uio_td;
1293
1294 error = vn_io_fault_doio(args, uio, td);
1295 if (error != EFAULT)
1296 goto out;
1297
1298 atomic_add_long(&vn_io_faults_cnt, 1);
1299 uio_clone->uio_segflg = UIO_NOCOPY;
1300 uiomove(NULL, resid - uio->uio_resid, uio_clone);
1301 uio_clone->uio_segflg = uio->uio_segflg;
1302
1303 saveheld = curthread_pflags_set(TDP_UIOHELD);
1304 prev_td_ma = td->td_ma;
1305 prev_td_ma_cnt = td->td_ma_cnt;
1306
1307 while (uio_clone->uio_resid != 0) {
1308 len = uio_clone->uio_iov->iov_len;
1309 if (len == 0) {
1310 KASSERT(uio_clone->uio_iovcnt >= 1,
1311 ("iovcnt underflow"));
1312 uio_clone->uio_iov++;
1313 uio_clone->uio_iovcnt--;
1314 continue;
1315 }
1316 if (len > ptoa(io_hold_cnt))
1317 len = ptoa(io_hold_cnt);
1318 addr = (uintptr_t)uio_clone->uio_iov->iov_base;
1319 end = round_page(addr + len);
1320 if (end < addr) {
1321 error = EFAULT;
1322 break;
1323 }
1324 cnt = atop(end - trunc_page(addr));
1325 /*
1326 * A perfectly misaligned address and length could cause
1327 * both the start and the end of the chunk to use partial
1328 * page. +2 accounts for such a situation.
1329 */
1330 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map,
1331 addr, len, prot, ma, io_hold_cnt + 2);
1332 if (cnt == -1) {
1333 error = EFAULT;
1334 break;
1335 }
1336 short_uio.uio_iov = &short_iovec[0];
1337 short_iovec[0].iov_base = (void *)addr;
1338 short_uio.uio_iovcnt = 1;
1339 short_uio.uio_resid = short_iovec[0].iov_len = len;
1340 short_uio.uio_offset = uio_clone->uio_offset;
1341 td->td_ma = ma;
1342 td->td_ma_cnt = cnt;
1343
1344 error = vn_io_fault_doio(args, &short_uio, td);
1345 vm_page_unhold_pages(ma, cnt);
1346 adv = len - short_uio.uio_resid;
1347
1348 uio_clone->uio_iov->iov_base =
1349 (char *)uio_clone->uio_iov->iov_base + adv;
1350 uio_clone->uio_iov->iov_len -= adv;
1351 uio_clone->uio_resid -= adv;
1352 uio_clone->uio_offset += adv;
1353
1354 uio->uio_resid -= adv;
1355 uio->uio_offset += adv;
1356
1357 if (error != 0 || adv == 0)
1358 break;
1359 }
1360 td->td_ma = prev_td_ma;
1361 td->td_ma_cnt = prev_td_ma_cnt;
1362 curthread_pflags_restore(saveheld);
1363 out:
1364 free(uio_clone, M_IOV);
1365 return (error);
1366 }
1367
1368 static int
vn_io_fault(struct file * fp,struct uio * uio,struct ucred * active_cred,int flags,struct thread * td)1369 vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred,
1370 int flags, struct thread *td)
1371 {
1372 fo_rdwr_t *doio;
1373 struct vnode *vp;
1374 void *rl_cookie;
1375 struct vn_io_fault_args args;
1376 int error;
1377
1378 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write;
1379 vp = fp->f_vnode;
1380
1381 /*
1382 * The ability to read(2) on a directory has historically been
1383 * allowed for all users, but this can and has been the source of
1384 * at least one security issue in the past. As such, it is now hidden
1385 * away behind a sysctl for those that actually need it to use it, and
1386 * restricted to root when it's turned on to make it relatively safe to
1387 * leave on for longer sessions of need.
1388 */
1389 if (vp->v_type == VDIR) {
1390 KASSERT(uio->uio_rw == UIO_READ,
1391 ("illegal write attempted on a directory"));
1392 if (!vfs_allow_read_dir)
1393 return (EISDIR);
1394 if ((error = priv_check(td, PRIV_VFS_READ_DIR)) != 0)
1395 return (EISDIR);
1396 }
1397
1398 foffset_lock_uio(fp, uio, flags);
1399 if (do_vn_io_fault(vp, uio)) {
1400 args.kind = VN_IO_FAULT_FOP;
1401 args.args.fop_args.fp = fp;
1402 args.args.fop_args.doio = doio;
1403 args.cred = active_cred;
1404 args.flags = flags | FOF_OFFSET;
1405 if (uio->uio_rw == UIO_READ) {
1406 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset,
1407 uio->uio_offset + uio->uio_resid);
1408 } else if ((fp->f_flag & O_APPEND) != 0 ||
1409 (flags & FOF_OFFSET) == 0) {
1410 /* For appenders, punt and lock the whole range. */
1411 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
1412 } else {
1413 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset,
1414 uio->uio_offset + uio->uio_resid);
1415 }
1416 error = vn_io_fault1(vp, uio, &args, td);
1417 vn_rangelock_unlock(vp, rl_cookie);
1418 } else {
1419 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td);
1420 }
1421 foffset_unlock_uio(fp, uio, flags);
1422 return (error);
1423 }
1424
1425 /*
1426 * Helper function to perform the requested uiomove operation using
1427 * the held pages for io->uio_iov[0].iov_base buffer instead of
1428 * copyin/copyout. Access to the pages with uiomove_fromphys()
1429 * instead of iov_base prevents page faults that could occur due to
1430 * pmap_collect() invalidating the mapping created by
1431 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or
1432 * object cleanup revoking the write access from page mappings.
1433 *
1434 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove()
1435 * instead of plain uiomove().
1436 */
1437 int
vn_io_fault_uiomove(char * data,int xfersize,struct uio * uio)1438 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio)
1439 {
1440 struct uio transp_uio;
1441 struct iovec transp_iov[1];
1442 struct thread *td;
1443 size_t adv;
1444 int error, pgadv;
1445
1446 td = curthread;
1447 if ((td->td_pflags & TDP_UIOHELD) == 0 ||
1448 uio->uio_segflg != UIO_USERSPACE)
1449 return (uiomove(data, xfersize, uio));
1450
1451 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt));
1452 transp_iov[0].iov_base = data;
1453 transp_uio.uio_iov = &transp_iov[0];
1454 transp_uio.uio_iovcnt = 1;
1455 if (xfersize > uio->uio_resid)
1456 xfersize = uio->uio_resid;
1457 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize;
1458 transp_uio.uio_offset = 0;
1459 transp_uio.uio_segflg = UIO_SYSSPACE;
1460 /*
1461 * Since transp_iov points to data, and td_ma page array
1462 * corresponds to original uio->uio_iov, we need to invert the
1463 * direction of the i/o operation as passed to
1464 * uiomove_fromphys().
1465 */
1466 switch (uio->uio_rw) {
1467 case UIO_WRITE:
1468 transp_uio.uio_rw = UIO_READ;
1469 break;
1470 case UIO_READ:
1471 transp_uio.uio_rw = UIO_WRITE;
1472 break;
1473 }
1474 transp_uio.uio_td = uio->uio_td;
1475 error = uiomove_fromphys(td->td_ma,
1476 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK,
1477 xfersize, &transp_uio);
1478 adv = xfersize - transp_uio.uio_resid;
1479 pgadv =
1480 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) -
1481 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT);
1482 td->td_ma += pgadv;
1483 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt,
1484 pgadv));
1485 td->td_ma_cnt -= pgadv;
1486 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv;
1487 uio->uio_iov->iov_len -= adv;
1488 uio->uio_resid -= adv;
1489 uio->uio_offset += adv;
1490 return (error);
1491 }
1492
1493 int
vn_io_fault_pgmove(vm_page_t ma[],vm_offset_t offset,int xfersize,struct uio * uio)1494 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize,
1495 struct uio *uio)
1496 {
1497 struct thread *td;
1498 vm_offset_t iov_base;
1499 int cnt, pgadv;
1500
1501 td = curthread;
1502 if ((td->td_pflags & TDP_UIOHELD) == 0 ||
1503 uio->uio_segflg != UIO_USERSPACE)
1504 return (uiomove_fromphys(ma, offset, xfersize, uio));
1505
1506 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt));
1507 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize;
1508 iov_base = (vm_offset_t)uio->uio_iov->iov_base;
1509 switch (uio->uio_rw) {
1510 case UIO_WRITE:
1511 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma,
1512 offset, cnt);
1513 break;
1514 case UIO_READ:
1515 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK,
1516 cnt);
1517 break;
1518 }
1519 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT);
1520 td->td_ma += pgadv;
1521 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt,
1522 pgadv));
1523 td->td_ma_cnt -= pgadv;
1524 uio->uio_iov->iov_base = (char *)(iov_base + cnt);
1525 uio->uio_iov->iov_len -= cnt;
1526 uio->uio_resid -= cnt;
1527 uio->uio_offset += cnt;
1528 return (0);
1529 }
1530
1531 /*
1532 * File table truncate routine.
1533 */
1534 static int
vn_truncate(struct file * fp,off_t length,struct ucred * active_cred,struct thread * td)1535 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred,
1536 struct thread *td)
1537 {
1538 struct mount *mp;
1539 struct vnode *vp;
1540 void *rl_cookie;
1541 int error;
1542
1543 vp = fp->f_vnode;
1544
1545 retry:
1546 /*
1547 * Lock the whole range for truncation. Otherwise split i/o
1548 * might happen partly before and partly after the truncation.
1549 */
1550 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
1551 error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
1552 if (error)
1553 goto out1;
1554 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1555 AUDIT_ARG_VNODE1(vp);
1556 if (vp->v_type == VDIR) {
1557 error = EISDIR;
1558 goto out;
1559 }
1560 #ifdef MAC
1561 error = mac_vnode_check_write(active_cred, fp->f_cred, vp);
1562 if (error)
1563 goto out;
1564 #endif
1565 error = vn_truncate_locked(vp, length, (fp->f_flag & O_FSYNC) != 0,
1566 fp->f_cred);
1567 out:
1568 VOP_UNLOCK(vp);
1569 vn_finished_write(mp);
1570 out1:
1571 vn_rangelock_unlock(vp, rl_cookie);
1572 if (error == ERELOOKUP)
1573 goto retry;
1574 return (error);
1575 }
1576
1577 /*
1578 * Truncate a file that is already locked.
1579 */
1580 int
vn_truncate_locked(struct vnode * vp,off_t length,bool sync,struct ucred * cred)1581 vn_truncate_locked(struct vnode *vp, off_t length, bool sync,
1582 struct ucred *cred)
1583 {
1584 struct vattr vattr;
1585 int error;
1586
1587 error = VOP_ADD_WRITECOUNT(vp, 1);
1588 if (error == 0) {
1589 VATTR_NULL(&vattr);
1590 vattr.va_size = length;
1591 if (sync)
1592 vattr.va_vaflags |= VA_SYNC;
1593 error = VOP_SETATTR(vp, &vattr, cred);
1594 VOP_ADD_WRITECOUNT_CHECKED(vp, -1);
1595 }
1596 return (error);
1597 }
1598
1599 /*
1600 * File table vnode stat routine.
1601 */
1602 static int
vn_statfile(struct file * fp,struct stat * sb,struct ucred * active_cred,struct thread * td)1603 vn_statfile(struct file *fp, struct stat *sb, struct ucred *active_cred,
1604 struct thread *td)
1605 {
1606 struct vnode *vp = fp->f_vnode;
1607 int error;
1608
1609 vn_lock(vp, LK_SHARED | LK_RETRY);
1610 error = VOP_STAT(vp, sb, active_cred, fp->f_cred, td);
1611 VOP_UNLOCK(vp);
1612
1613 return (error);
1614 }
1615
1616 /*
1617 * File table vnode ioctl routine.
1618 */
1619 static int
vn_ioctl(struct file * fp,u_long com,void * data,struct ucred * active_cred,struct thread * td)1620 vn_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred,
1621 struct thread *td)
1622 {
1623 struct vattr vattr;
1624 struct vnode *vp;
1625 struct fiobmap2_arg *bmarg;
1626 int error;
1627
1628 vp = fp->f_vnode;
1629 switch (vp->v_type) {
1630 case VDIR:
1631 case VREG:
1632 switch (com) {
1633 case FIONREAD:
1634 vn_lock(vp, LK_SHARED | LK_RETRY);
1635 error = VOP_GETATTR(vp, &vattr, active_cred);
1636 VOP_UNLOCK(vp);
1637 if (error == 0)
1638 *(int *)data = vattr.va_size - fp->f_offset;
1639 return (error);
1640 case FIOBMAP2:
1641 bmarg = (struct fiobmap2_arg *)data;
1642 vn_lock(vp, LK_SHARED | LK_RETRY);
1643 #ifdef MAC
1644 error = mac_vnode_check_read(active_cred, fp->f_cred,
1645 vp);
1646 if (error == 0)
1647 #endif
1648 error = VOP_BMAP(vp, bmarg->bn, NULL,
1649 &bmarg->bn, &bmarg->runp, &bmarg->runb);
1650 VOP_UNLOCK(vp);
1651 return (error);
1652 case FIONBIO:
1653 case FIOASYNC:
1654 return (0);
1655 default:
1656 return (VOP_IOCTL(vp, com, data, fp->f_flag,
1657 active_cred, td));
1658 }
1659 break;
1660 case VCHR:
1661 return (VOP_IOCTL(vp, com, data, fp->f_flag,
1662 active_cred, td));
1663 default:
1664 return (ENOTTY);
1665 }
1666 }
1667
1668 /*
1669 * File table vnode poll routine.
1670 */
1671 static int
vn_poll(struct file * fp,int events,struct ucred * active_cred,struct thread * td)1672 vn_poll(struct file *fp, int events, struct ucred *active_cred,
1673 struct thread *td)
1674 {
1675 struct vnode *vp;
1676 int error;
1677
1678 vp = fp->f_vnode;
1679 #if defined(MAC) || defined(AUDIT)
1680 if (AUDITING_TD(td) || mac_vnode_check_poll_enabled()) {
1681 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1682 AUDIT_ARG_VNODE1(vp);
1683 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp);
1684 VOP_UNLOCK(vp);
1685 if (error != 0)
1686 return (error);
1687 }
1688 #endif
1689 error = VOP_POLL(vp, events, fp->f_cred, td);
1690 return (error);
1691 }
1692
1693 /*
1694 * Acquire the requested lock and then check for validity. LK_RETRY
1695 * permits vn_lock to return doomed vnodes.
1696 */
1697 static int __noinline
_vn_lock_fallback(struct vnode * vp,int flags,const char * file,int line,int error)1698 _vn_lock_fallback(struct vnode *vp, int flags, const char *file, int line,
1699 int error)
1700 {
1701
1702 KASSERT((flags & LK_RETRY) == 0 || error == 0,
1703 ("vn_lock: error %d incompatible with flags %#x", error, flags));
1704
1705 if (error == 0)
1706 VNASSERT(VN_IS_DOOMED(vp), vp, ("vnode not doomed"));
1707
1708 if ((flags & LK_RETRY) == 0) {
1709 if (error == 0) {
1710 VOP_UNLOCK(vp);
1711 error = ENOENT;
1712 }
1713 return (error);
1714 }
1715
1716 /*
1717 * LK_RETRY case.
1718 *
1719 * Nothing to do if we got the lock.
1720 */
1721 if (error == 0)
1722 return (0);
1723
1724 /*
1725 * Interlock was dropped by the call in _vn_lock.
1726 */
1727 flags &= ~LK_INTERLOCK;
1728 do {
1729 error = VOP_LOCK1(vp, flags, file, line);
1730 } while (error != 0);
1731 return (0);
1732 }
1733
1734 int
_vn_lock(struct vnode * vp,int flags,const char * file,int line)1735 _vn_lock(struct vnode *vp, int flags, const char *file, int line)
1736 {
1737 int error;
1738
1739 VNASSERT((flags & LK_TYPE_MASK) != 0, vp,
1740 ("vn_lock: no locktype (%d passed)", flags));
1741 VNPASS(vp->v_holdcnt > 0, vp);
1742 error = VOP_LOCK1(vp, flags, file, line);
1743 if (__predict_false(error != 0 || VN_IS_DOOMED(vp)))
1744 return (_vn_lock_fallback(vp, flags, file, line, error));
1745 return (0);
1746 }
1747
1748 /*
1749 * File table vnode close routine.
1750 */
1751 static int
vn_closefile(struct file * fp,struct thread * td)1752 vn_closefile(struct file *fp, struct thread *td)
1753 {
1754 struct vnode *vp;
1755 struct flock lf;
1756 int error;
1757 bool ref;
1758
1759 vp = fp->f_vnode;
1760 fp->f_ops = &badfileops;
1761 ref= (fp->f_flag & FHASLOCK) != 0 && fp->f_type == DTYPE_VNODE;
1762
1763 error = vn_close1(vp, fp->f_flag, fp->f_cred, td, ref);
1764
1765 if (__predict_false(ref)) {
1766 lf.l_whence = SEEK_SET;
1767 lf.l_start = 0;
1768 lf.l_len = 0;
1769 lf.l_type = F_UNLCK;
1770 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK);
1771 vrele(vp);
1772 }
1773 return (error);
1774 }
1775
1776 /*
1777 * Preparing to start a filesystem write operation. If the operation is
1778 * permitted, then we bump the count of operations in progress and
1779 * proceed. If a suspend request is in progress, we wait until the
1780 * suspension is over, and then proceed.
1781 */
1782 static int
vn_start_write_refed(struct mount * mp,int flags,bool mplocked)1783 vn_start_write_refed(struct mount *mp, int flags, bool mplocked)
1784 {
1785 struct mount_pcpu *mpcpu;
1786 int error, mflags;
1787
1788 if (__predict_true(!mplocked) && (flags & V_XSLEEP) == 0 &&
1789 vfs_op_thread_enter(mp, mpcpu)) {
1790 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0);
1791 vfs_mp_count_add_pcpu(mpcpu, writeopcount, 1);
1792 vfs_op_thread_exit(mp, mpcpu);
1793 return (0);
1794 }
1795
1796 if (mplocked)
1797 mtx_assert(MNT_MTX(mp), MA_OWNED);
1798 else
1799 MNT_ILOCK(mp);
1800
1801 error = 0;
1802
1803 /*
1804 * Check on status of suspension.
1805 */
1806 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 ||
1807 mp->mnt_susp_owner != curthread) {
1808 mflags = ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ?
1809 (flags & PCATCH) : 0) | (PUSER - 1);
1810 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
1811 if (flags & V_NOWAIT) {
1812 error = EWOULDBLOCK;
1813 goto unlock;
1814 }
1815 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags,
1816 "suspfs", 0);
1817 if (error)
1818 goto unlock;
1819 }
1820 }
1821 if (flags & V_XSLEEP)
1822 goto unlock;
1823 mp->mnt_writeopcount++;
1824 unlock:
1825 if (error != 0 || (flags & V_XSLEEP) != 0)
1826 MNT_REL(mp);
1827 MNT_IUNLOCK(mp);
1828 return (error);
1829 }
1830
1831 int
vn_start_write(struct vnode * vp,struct mount ** mpp,int flags)1832 vn_start_write(struct vnode *vp, struct mount **mpp, int flags)
1833 {
1834 struct mount *mp;
1835 int error;
1836
1837 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
1838 ("V_MNTREF requires mp"));
1839
1840 error = 0;
1841 /*
1842 * If a vnode is provided, get and return the mount point that
1843 * to which it will write.
1844 */
1845 if (vp != NULL) {
1846 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
1847 *mpp = NULL;
1848 if (error != EOPNOTSUPP)
1849 return (error);
1850 return (0);
1851 }
1852 }
1853 if ((mp = *mpp) == NULL)
1854 return (0);
1855
1856 /*
1857 * VOP_GETWRITEMOUNT() returns with the mp refcount held through
1858 * a vfs_ref().
1859 * As long as a vnode is not provided we need to acquire a
1860 * refcount for the provided mountpoint too, in order to
1861 * emulate a vfs_ref().
1862 */
1863 if (vp == NULL && (flags & V_MNTREF) == 0)
1864 vfs_ref(mp);
1865
1866 return (vn_start_write_refed(mp, flags, false));
1867 }
1868
1869 /*
1870 * Secondary suspension. Used by operations such as vop_inactive
1871 * routines that are needed by the higher level functions. These
1872 * are allowed to proceed until all the higher level functions have
1873 * completed (indicated by mnt_writeopcount dropping to zero). At that
1874 * time, these operations are halted until the suspension is over.
1875 */
1876 int
vn_start_secondary_write(struct vnode * vp,struct mount ** mpp,int flags)1877 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags)
1878 {
1879 struct mount *mp;
1880 int error;
1881
1882 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
1883 ("V_MNTREF requires mp"));
1884
1885 retry:
1886 if (vp != NULL) {
1887 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
1888 *mpp = NULL;
1889 if (error != EOPNOTSUPP)
1890 return (error);
1891 return (0);
1892 }
1893 }
1894 /*
1895 * If we are not suspended or have not yet reached suspended
1896 * mode, then let the operation proceed.
1897 */
1898 if ((mp = *mpp) == NULL)
1899 return (0);
1900
1901 /*
1902 * VOP_GETWRITEMOUNT() returns with the mp refcount held through
1903 * a vfs_ref().
1904 * As long as a vnode is not provided we need to acquire a
1905 * refcount for the provided mountpoint too, in order to
1906 * emulate a vfs_ref().
1907 */
1908 MNT_ILOCK(mp);
1909 if (vp == NULL && (flags & V_MNTREF) == 0)
1910 MNT_REF(mp);
1911 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) {
1912 mp->mnt_secondary_writes++;
1913 mp->mnt_secondary_accwrites++;
1914 MNT_IUNLOCK(mp);
1915 return (0);
1916 }
1917 if (flags & V_NOWAIT) {
1918 MNT_REL(mp);
1919 MNT_IUNLOCK(mp);
1920 return (EWOULDBLOCK);
1921 }
1922 /*
1923 * Wait for the suspension to finish.
1924 */
1925 error = msleep(&mp->mnt_flag, MNT_MTX(mp), (PUSER - 1) | PDROP |
1926 ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? (flags & PCATCH) : 0),
1927 "suspfs", 0);
1928 vfs_rel(mp);
1929 if (error == 0)
1930 goto retry;
1931 return (error);
1932 }
1933
1934 /*
1935 * Filesystem write operation has completed. If we are suspending and this
1936 * operation is the last one, notify the suspender that the suspension is
1937 * now in effect.
1938 */
1939 void
vn_finished_write(struct mount * mp)1940 vn_finished_write(struct mount *mp)
1941 {
1942 struct mount_pcpu *mpcpu;
1943 int c;
1944
1945 if (mp == NULL)
1946 return;
1947
1948 if (vfs_op_thread_enter(mp, mpcpu)) {
1949 vfs_mp_count_sub_pcpu(mpcpu, writeopcount, 1);
1950 vfs_mp_count_sub_pcpu(mpcpu, ref, 1);
1951 vfs_op_thread_exit(mp, mpcpu);
1952 return;
1953 }
1954
1955 MNT_ILOCK(mp);
1956 vfs_assert_mount_counters(mp);
1957 MNT_REL(mp);
1958 c = --mp->mnt_writeopcount;
1959 if (mp->mnt_vfs_ops == 0) {
1960 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0);
1961 MNT_IUNLOCK(mp);
1962 return;
1963 }
1964 if (c < 0)
1965 vfs_dump_mount_counters(mp);
1966 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && c == 0)
1967 wakeup(&mp->mnt_writeopcount);
1968 MNT_IUNLOCK(mp);
1969 }
1970
1971 /*
1972 * Filesystem secondary write operation has completed. If we are
1973 * suspending and this operation is the last one, notify the suspender
1974 * that the suspension is now in effect.
1975 */
1976 void
vn_finished_secondary_write(struct mount * mp)1977 vn_finished_secondary_write(struct mount *mp)
1978 {
1979 if (mp == NULL)
1980 return;
1981 MNT_ILOCK(mp);
1982 MNT_REL(mp);
1983 mp->mnt_secondary_writes--;
1984 if (mp->mnt_secondary_writes < 0)
1985 panic("vn_finished_secondary_write: neg cnt");
1986 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 &&
1987 mp->mnt_secondary_writes <= 0)
1988 wakeup(&mp->mnt_secondary_writes);
1989 MNT_IUNLOCK(mp);
1990 }
1991
1992 /*
1993 * Request a filesystem to suspend write operations.
1994 */
1995 int
vfs_write_suspend(struct mount * mp,int flags)1996 vfs_write_suspend(struct mount *mp, int flags)
1997 {
1998 int error;
1999
2000 vfs_op_enter(mp);
2001
2002 MNT_ILOCK(mp);
2003 vfs_assert_mount_counters(mp);
2004 if (mp->mnt_susp_owner == curthread) {
2005 vfs_op_exit_locked(mp);
2006 MNT_IUNLOCK(mp);
2007 return (EALREADY);
2008 }
2009 while (mp->mnt_kern_flag & MNTK_SUSPEND)
2010 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0);
2011
2012 /*
2013 * Unmount holds a write reference on the mount point. If we
2014 * own busy reference and drain for writers, we deadlock with
2015 * the reference draining in the unmount path. Callers of
2016 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if
2017 * vfs_busy() reference is owned and caller is not in the
2018 * unmount context.
2019 */
2020 if ((flags & VS_SKIP_UNMOUNT) != 0 &&
2021 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) {
2022 vfs_op_exit_locked(mp);
2023 MNT_IUNLOCK(mp);
2024 return (EBUSY);
2025 }
2026
2027 mp->mnt_kern_flag |= MNTK_SUSPEND;
2028 mp->mnt_susp_owner = curthread;
2029 if (mp->mnt_writeopcount > 0)
2030 (void) msleep(&mp->mnt_writeopcount,
2031 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0);
2032 else
2033 MNT_IUNLOCK(mp);
2034 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0) {
2035 vfs_write_resume(mp, 0);
2036 /* vfs_write_resume does vfs_op_exit() for us */
2037 }
2038 return (error);
2039 }
2040
2041 /*
2042 * Request a filesystem to resume write operations.
2043 */
2044 void
vfs_write_resume(struct mount * mp,int flags)2045 vfs_write_resume(struct mount *mp, int flags)
2046 {
2047
2048 MNT_ILOCK(mp);
2049 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
2050 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner"));
2051 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 |
2052 MNTK_SUSPENDED);
2053 mp->mnt_susp_owner = NULL;
2054 wakeup(&mp->mnt_writeopcount);
2055 wakeup(&mp->mnt_flag);
2056 curthread->td_pflags &= ~TDP_IGNSUSP;
2057 if ((flags & VR_START_WRITE) != 0) {
2058 MNT_REF(mp);
2059 mp->mnt_writeopcount++;
2060 }
2061 MNT_IUNLOCK(mp);
2062 if ((flags & VR_NO_SUSPCLR) == 0)
2063 VFS_SUSP_CLEAN(mp);
2064 vfs_op_exit(mp);
2065 } else if ((flags & VR_START_WRITE) != 0) {
2066 MNT_REF(mp);
2067 vn_start_write_refed(mp, 0, true);
2068 } else {
2069 MNT_IUNLOCK(mp);
2070 }
2071 }
2072
2073 /*
2074 * Helper loop around vfs_write_suspend() for filesystem unmount VFS
2075 * methods.
2076 */
2077 int
vfs_write_suspend_umnt(struct mount * mp)2078 vfs_write_suspend_umnt(struct mount *mp)
2079 {
2080 int error;
2081
2082 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0,
2083 ("vfs_write_suspend_umnt: recursed"));
2084
2085 /* dounmount() already called vn_start_write(). */
2086 for (;;) {
2087 vn_finished_write(mp);
2088 error = vfs_write_suspend(mp, 0);
2089 if (error != 0) {
2090 vn_start_write(NULL, &mp, V_WAIT);
2091 return (error);
2092 }
2093 MNT_ILOCK(mp);
2094 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0)
2095 break;
2096 MNT_IUNLOCK(mp);
2097 vn_start_write(NULL, &mp, V_WAIT);
2098 }
2099 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2);
2100 wakeup(&mp->mnt_flag);
2101 MNT_IUNLOCK(mp);
2102 curthread->td_pflags |= TDP_IGNSUSP;
2103 return (0);
2104 }
2105
2106 /*
2107 * Implement kqueues for files by translating it to vnode operation.
2108 */
2109 static int
vn_kqfilter(struct file * fp,struct knote * kn)2110 vn_kqfilter(struct file *fp, struct knote *kn)
2111 {
2112
2113 return (VOP_KQFILTER(fp->f_vnode, kn));
2114 }
2115
2116 /*
2117 * Simplified in-kernel wrapper calls for extended attribute access.
2118 * Both calls pass in a NULL credential, authorizing as "kernel" access.
2119 * Set IO_NODELOCKED in ioflg if the vnode is already locked.
2120 */
2121 int
vn_extattr_get(struct vnode * vp,int ioflg,int attrnamespace,const char * attrname,int * buflen,char * buf,struct thread * td)2122 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace,
2123 const char *attrname, int *buflen, char *buf, struct thread *td)
2124 {
2125 struct uio auio;
2126 struct iovec iov;
2127 int error;
2128
2129 iov.iov_len = *buflen;
2130 iov.iov_base = buf;
2131
2132 auio.uio_iov = &iov;
2133 auio.uio_iovcnt = 1;
2134 auio.uio_rw = UIO_READ;
2135 auio.uio_segflg = UIO_SYSSPACE;
2136 auio.uio_td = td;
2137 auio.uio_offset = 0;
2138 auio.uio_resid = *buflen;
2139
2140 if ((ioflg & IO_NODELOCKED) == 0)
2141 vn_lock(vp, LK_SHARED | LK_RETRY);
2142
2143 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
2144
2145 /* authorize attribute retrieval as kernel */
2146 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL,
2147 td);
2148
2149 if ((ioflg & IO_NODELOCKED) == 0)
2150 VOP_UNLOCK(vp);
2151
2152 if (error == 0) {
2153 *buflen = *buflen - auio.uio_resid;
2154 }
2155
2156 return (error);
2157 }
2158
2159 /*
2160 * XXX failure mode if partially written?
2161 */
2162 int
vn_extattr_set(struct vnode * vp,int ioflg,int attrnamespace,const char * attrname,int buflen,char * buf,struct thread * td)2163 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace,
2164 const char *attrname, int buflen, char *buf, struct thread *td)
2165 {
2166 struct uio auio;
2167 struct iovec iov;
2168 struct mount *mp;
2169 int error;
2170
2171 iov.iov_len = buflen;
2172 iov.iov_base = buf;
2173
2174 auio.uio_iov = &iov;
2175 auio.uio_iovcnt = 1;
2176 auio.uio_rw = UIO_WRITE;
2177 auio.uio_segflg = UIO_SYSSPACE;
2178 auio.uio_td = td;
2179 auio.uio_offset = 0;
2180 auio.uio_resid = buflen;
2181
2182 if ((ioflg & IO_NODELOCKED) == 0) {
2183 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0)
2184 return (error);
2185 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2186 }
2187
2188 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
2189
2190 /* authorize attribute setting as kernel */
2191 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td);
2192
2193 if ((ioflg & IO_NODELOCKED) == 0) {
2194 vn_finished_write(mp);
2195 VOP_UNLOCK(vp);
2196 }
2197
2198 return (error);
2199 }
2200
2201 int
vn_extattr_rm(struct vnode * vp,int ioflg,int attrnamespace,const char * attrname,struct thread * td)2202 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace,
2203 const char *attrname, struct thread *td)
2204 {
2205 struct mount *mp;
2206 int error;
2207
2208 if ((ioflg & IO_NODELOCKED) == 0) {
2209 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0)
2210 return (error);
2211 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2212 }
2213
2214 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
2215
2216 /* authorize attribute removal as kernel */
2217 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td);
2218 if (error == EOPNOTSUPP)
2219 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL,
2220 NULL, td);
2221
2222 if ((ioflg & IO_NODELOCKED) == 0) {
2223 vn_finished_write(mp);
2224 VOP_UNLOCK(vp);
2225 }
2226
2227 return (error);
2228 }
2229
2230 static int
vn_get_ino_alloc_vget(struct mount * mp,void * arg,int lkflags,struct vnode ** rvp)2231 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags,
2232 struct vnode **rvp)
2233 {
2234
2235 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp));
2236 }
2237
2238 int
vn_vget_ino(struct vnode * vp,ino_t ino,int lkflags,struct vnode ** rvp)2239 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp)
2240 {
2241
2242 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino,
2243 lkflags, rvp));
2244 }
2245
2246 int
vn_vget_ino_gen(struct vnode * vp,vn_get_ino_t alloc,void * alloc_arg,int lkflags,struct vnode ** rvp)2247 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg,
2248 int lkflags, struct vnode **rvp)
2249 {
2250 struct mount *mp;
2251 int ltype, error;
2252
2253 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get");
2254 mp = vp->v_mount;
2255 ltype = VOP_ISLOCKED(vp);
2256 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED,
2257 ("vn_vget_ino: vp not locked"));
2258 error = vfs_busy(mp, MBF_NOWAIT);
2259 if (error != 0) {
2260 vfs_ref(mp);
2261 VOP_UNLOCK(vp);
2262 error = vfs_busy(mp, 0);
2263 vn_lock(vp, ltype | LK_RETRY);
2264 vfs_rel(mp);
2265 if (error != 0)
2266 return (ENOENT);
2267 if (VN_IS_DOOMED(vp)) {
2268 vfs_unbusy(mp);
2269 return (ENOENT);
2270 }
2271 }
2272 VOP_UNLOCK(vp);
2273 error = alloc(mp, alloc_arg, lkflags, rvp);
2274 vfs_unbusy(mp);
2275 if (error != 0 || *rvp != vp)
2276 vn_lock(vp, ltype | LK_RETRY);
2277 if (VN_IS_DOOMED(vp)) {
2278 if (error == 0) {
2279 if (*rvp == vp)
2280 vunref(vp);
2281 else
2282 vput(*rvp);
2283 }
2284 error = ENOENT;
2285 }
2286 return (error);
2287 }
2288
2289 int
vn_rlimit_fsize(const struct vnode * vp,const struct uio * uio,struct thread * td)2290 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio,
2291 struct thread *td)
2292 {
2293
2294 if (vp->v_type != VREG || td == NULL)
2295 return (0);
2296 if ((uoff_t)uio->uio_offset + uio->uio_resid >
2297 lim_cur(td, RLIMIT_FSIZE)) {
2298 PROC_LOCK(td->td_proc);
2299 kern_psignal(td->td_proc, SIGXFSZ);
2300 PROC_UNLOCK(td->td_proc);
2301 return (EFBIG);
2302 }
2303 return (0);
2304 }
2305
2306 int
vn_chmod(struct file * fp,mode_t mode,struct ucred * active_cred,struct thread * td)2307 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred,
2308 struct thread *td)
2309 {
2310 struct vnode *vp;
2311
2312 vp = fp->f_vnode;
2313 #ifdef AUDIT
2314 vn_lock(vp, LK_SHARED | LK_RETRY);
2315 AUDIT_ARG_VNODE1(vp);
2316 VOP_UNLOCK(vp);
2317 #endif
2318 return (setfmode(td, active_cred, vp, mode));
2319 }
2320
2321 int
vn_chown(struct file * fp,uid_t uid,gid_t gid,struct ucred * active_cred,struct thread * td)2322 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
2323 struct thread *td)
2324 {
2325 struct vnode *vp;
2326
2327 vp = fp->f_vnode;
2328 #ifdef AUDIT
2329 vn_lock(vp, LK_SHARED | LK_RETRY);
2330 AUDIT_ARG_VNODE1(vp);
2331 VOP_UNLOCK(vp);
2332 #endif
2333 return (setfown(td, active_cred, vp, uid, gid));
2334 }
2335
2336 void
vn_pages_remove(struct vnode * vp,vm_pindex_t start,vm_pindex_t end)2337 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end)
2338 {
2339 vm_object_t object;
2340
2341 if ((object = vp->v_object) == NULL)
2342 return;
2343 VM_OBJECT_WLOCK(object);
2344 vm_object_page_remove(object, start, end, 0);
2345 VM_OBJECT_WUNLOCK(object);
2346 }
2347
2348 int
vn_bmap_seekhole(struct vnode * vp,u_long cmd,off_t * off,struct ucred * cred)2349 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred)
2350 {
2351 struct vattr va;
2352 daddr_t bn, bnp;
2353 uint64_t bsize;
2354 off_t noff;
2355 int error;
2356
2357 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA,
2358 ("Wrong command %lu", cmd));
2359
2360 if (vn_lock(vp, LK_SHARED) != 0)
2361 return (EBADF);
2362 if (vp->v_type != VREG) {
2363 error = ENOTTY;
2364 goto unlock;
2365 }
2366 error = VOP_GETATTR(vp, &va, cred);
2367 if (error != 0)
2368 goto unlock;
2369 noff = *off;
2370 if (noff >= va.va_size) {
2371 error = ENXIO;
2372 goto unlock;
2373 }
2374 bsize = vp->v_mount->mnt_stat.f_iosize;
2375 for (bn = noff / bsize; noff < va.va_size; bn++, noff += bsize -
2376 noff % bsize) {
2377 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL);
2378 if (error == EOPNOTSUPP) {
2379 error = ENOTTY;
2380 goto unlock;
2381 }
2382 if ((bnp == -1 && cmd == FIOSEEKHOLE) ||
2383 (bnp != -1 && cmd == FIOSEEKDATA)) {
2384 noff = bn * bsize;
2385 if (noff < *off)
2386 noff = *off;
2387 goto unlock;
2388 }
2389 }
2390 if (noff > va.va_size)
2391 noff = va.va_size;
2392 /* noff == va.va_size. There is an implicit hole at the end of file. */
2393 if (cmd == FIOSEEKDATA)
2394 error = ENXIO;
2395 unlock:
2396 VOP_UNLOCK(vp);
2397 if (error == 0)
2398 *off = noff;
2399 return (error);
2400 }
2401
2402 int
vn_seek(struct file * fp,off_t offset,int whence,struct thread * td)2403 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td)
2404 {
2405 struct ucred *cred;
2406 struct vnode *vp;
2407 struct vattr vattr;
2408 off_t foffset, size;
2409 int error, noneg;
2410
2411 cred = td->td_ucred;
2412 vp = fp->f_vnode;
2413 foffset = foffset_lock(fp, 0);
2414 noneg = (vp->v_type != VCHR);
2415 error = 0;
2416 switch (whence) {
2417 case L_INCR:
2418 if (noneg &&
2419 (foffset < 0 ||
2420 (offset > 0 && foffset > OFF_MAX - offset))) {
2421 error = EOVERFLOW;
2422 break;
2423 }
2424 offset += foffset;
2425 break;
2426 case L_XTND:
2427 vn_lock(vp, LK_SHARED | LK_RETRY);
2428 error = VOP_GETATTR(vp, &vattr, cred);
2429 VOP_UNLOCK(vp);
2430 if (error)
2431 break;
2432
2433 /*
2434 * If the file references a disk device, then fetch
2435 * the media size and use that to determine the ending
2436 * offset.
2437 */
2438 if (vattr.va_size == 0 && vp->v_type == VCHR &&
2439 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0)
2440 vattr.va_size = size;
2441 if (noneg &&
2442 (vattr.va_size > OFF_MAX ||
2443 (offset > 0 && vattr.va_size > OFF_MAX - offset))) {
2444 error = EOVERFLOW;
2445 break;
2446 }
2447 offset += vattr.va_size;
2448 break;
2449 case L_SET:
2450 break;
2451 case SEEK_DATA:
2452 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td);
2453 if (error == ENOTTY)
2454 error = EINVAL;
2455 break;
2456 case SEEK_HOLE:
2457 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td);
2458 if (error == ENOTTY)
2459 error = EINVAL;
2460 break;
2461 default:
2462 error = EINVAL;
2463 }
2464 if (error == 0 && noneg && offset < 0)
2465 error = EINVAL;
2466 if (error != 0)
2467 goto drop;
2468 VFS_KNOTE_UNLOCKED(vp, 0);
2469 td->td_uretoff.tdu_off = offset;
2470 drop:
2471 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0);
2472 return (error);
2473 }
2474
2475 int
vn_utimes_perm(struct vnode * vp,struct vattr * vap,struct ucred * cred,struct thread * td)2476 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred,
2477 struct thread *td)
2478 {
2479 int error;
2480
2481 /*
2482 * Grant permission if the caller is the owner of the file, or
2483 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on
2484 * on the file. If the time pointer is null, then write
2485 * permission on the file is also sufficient.
2486 *
2487 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes:
2488 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES
2489 * will be allowed to set the times [..] to the current
2490 * server time.
2491 */
2492 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td);
2493 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0)
2494 error = VOP_ACCESS(vp, VWRITE, cred, td);
2495 return (error);
2496 }
2497
2498 int
vn_fill_kinfo(struct file * fp,struct kinfo_file * kif,struct filedesc * fdp)2499 vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
2500 {
2501 struct vnode *vp;
2502 int error;
2503
2504 if (fp->f_type == DTYPE_FIFO)
2505 kif->kf_type = KF_TYPE_FIFO;
2506 else
2507 kif->kf_type = KF_TYPE_VNODE;
2508 vp = fp->f_vnode;
2509 vref(vp);
2510 FILEDESC_SUNLOCK(fdp);
2511 error = vn_fill_kinfo_vnode(vp, kif);
2512 vrele(vp);
2513 FILEDESC_SLOCK(fdp);
2514 return (error);
2515 }
2516
2517 static inline void
vn_fill_junk(struct kinfo_file * kif)2518 vn_fill_junk(struct kinfo_file *kif)
2519 {
2520 size_t len, olen;
2521
2522 /*
2523 * Simulate vn_fullpath returning changing values for a given
2524 * vp during e.g. coredump.
2525 */
2526 len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1;
2527 olen = strlen(kif->kf_path);
2528 if (len < olen)
2529 strcpy(&kif->kf_path[len - 1], "$");
2530 else
2531 for (; olen < len; olen++)
2532 strcpy(&kif->kf_path[olen], "A");
2533 }
2534
2535 int
vn_fill_kinfo_vnode(struct vnode * vp,struct kinfo_file * kif)2536 vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif)
2537 {
2538 struct vattr va;
2539 char *fullpath, *freepath;
2540 int error;
2541
2542 kif->kf_un.kf_file.kf_file_type = vntype_to_kinfo(vp->v_type);
2543 freepath = NULL;
2544 fullpath = "-";
2545 error = vn_fullpath(vp, &fullpath, &freepath);
2546 if (error == 0) {
2547 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path));
2548 }
2549 if (freepath != NULL)
2550 free(freepath, M_TEMP);
2551
2552 KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path,
2553 vn_fill_junk(kif);
2554 );
2555
2556 /*
2557 * Retrieve vnode attributes.
2558 */
2559 va.va_fsid = VNOVAL;
2560 va.va_rdev = NODEV;
2561 vn_lock(vp, LK_SHARED | LK_RETRY);
2562 error = VOP_GETATTR(vp, &va, curthread->td_ucred);
2563 VOP_UNLOCK(vp);
2564 if (error != 0)
2565 return (error);
2566 if (va.va_fsid != VNOVAL)
2567 kif->kf_un.kf_file.kf_file_fsid = va.va_fsid;
2568 else
2569 kif->kf_un.kf_file.kf_file_fsid =
2570 vp->v_mount->mnt_stat.f_fsid.val[0];
2571 kif->kf_un.kf_file.kf_file_fsid_freebsd11 =
2572 kif->kf_un.kf_file.kf_file_fsid; /* truncate */
2573 kif->kf_un.kf_file.kf_file_fileid = va.va_fileid;
2574 kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode);
2575 kif->kf_un.kf_file.kf_file_size = va.va_size;
2576 kif->kf_un.kf_file.kf_file_rdev = va.va_rdev;
2577 kif->kf_un.kf_file.kf_file_rdev_freebsd11 =
2578 kif->kf_un.kf_file.kf_file_rdev; /* truncate */
2579 return (0);
2580 }
2581
2582 int
vn_mmap(struct file * fp,vm_map_t map,vm_offset_t * addr,vm_size_t size,vm_prot_t prot,vm_prot_t cap_maxprot,int flags,vm_ooffset_t foff,struct thread * td)2583 vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size,
2584 vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff,
2585 struct thread *td)
2586 {
2587 #ifdef HWPMC_HOOKS
2588 struct pmckern_map_in pkm;
2589 #endif
2590 struct mount *mp;
2591 struct vnode *vp;
2592 vm_object_t object;
2593 vm_prot_t maxprot;
2594 boolean_t writecounted;
2595 int error;
2596
2597 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \
2598 defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4)
2599 /*
2600 * POSIX shared-memory objects are defined to have
2601 * kernel persistence, and are not defined to support
2602 * read(2)/write(2) -- or even open(2). Thus, we can
2603 * use MAP_ASYNC to trade on-disk coherence for speed.
2604 * The shm_open(3) library routine turns on the FPOSIXSHM
2605 * flag to request this behavior.
2606 */
2607 if ((fp->f_flag & FPOSIXSHM) != 0)
2608 flags |= MAP_NOSYNC;
2609 #endif
2610 vp = fp->f_vnode;
2611
2612 /*
2613 * Ensure that file and memory protections are
2614 * compatible. Note that we only worry about
2615 * writability if mapping is shared; in this case,
2616 * current and max prot are dictated by the open file.
2617 * XXX use the vnode instead? Problem is: what
2618 * credentials do we use for determination? What if
2619 * proc does a setuid?
2620 */
2621 mp = vp->v_mount;
2622 if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) {
2623 maxprot = VM_PROT_NONE;
2624 if ((prot & VM_PROT_EXECUTE) != 0)
2625 return (EACCES);
2626 } else
2627 maxprot = VM_PROT_EXECUTE;
2628 if ((fp->f_flag & FREAD) != 0)
2629 maxprot |= VM_PROT_READ;
2630 else if ((prot & VM_PROT_READ) != 0)
2631 return (EACCES);
2632
2633 /*
2634 * If we are sharing potential changes via MAP_SHARED and we
2635 * are trying to get write permission although we opened it
2636 * without asking for it, bail out.
2637 */
2638 if ((flags & MAP_SHARED) != 0) {
2639 if ((fp->f_flag & FWRITE) != 0)
2640 maxprot |= VM_PROT_WRITE;
2641 else if ((prot & VM_PROT_WRITE) != 0)
2642 return (EACCES);
2643 } else {
2644 maxprot |= VM_PROT_WRITE;
2645 cap_maxprot |= VM_PROT_WRITE;
2646 }
2647 maxprot &= cap_maxprot;
2648
2649 /*
2650 * For regular files and shared memory, POSIX requires that
2651 * the value of foff be a legitimate offset within the data
2652 * object. In particular, negative offsets are invalid.
2653 * Blocking negative offsets and overflows here avoids
2654 * possible wraparound or user-level access into reserved
2655 * ranges of the data object later. In contrast, POSIX does
2656 * not dictate how offsets are used by device drivers, so in
2657 * the case of a device mapping a negative offset is passed
2658 * on.
2659 */
2660 if (
2661 #ifdef _LP64
2662 size > OFF_MAX ||
2663 #endif
2664 foff > OFF_MAX - size)
2665 return (EINVAL);
2666
2667 writecounted = FALSE;
2668 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp,
2669 &foff, &object, &writecounted);
2670 if (error != 0)
2671 return (error);
2672 error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object,
2673 foff, writecounted, td);
2674 if (error != 0) {
2675 /*
2676 * If this mapping was accounted for in the vnode's
2677 * writecount, then undo that now.
2678 */
2679 if (writecounted)
2680 vm_pager_release_writecount(object, 0, size);
2681 vm_object_deallocate(object);
2682 }
2683 #ifdef HWPMC_HOOKS
2684 /* Inform hwpmc(4) if an executable is being mapped. */
2685 if (PMC_HOOK_INSTALLED(PMC_FN_MMAP)) {
2686 if ((prot & VM_PROT_EXECUTE) != 0 && error == 0) {
2687 pkm.pm_file = vp;
2688 pkm.pm_address = (uintptr_t) *addr;
2689 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_MMAP, (void *) &pkm);
2690 }
2691 }
2692 #endif
2693 return (error);
2694 }
2695
2696 void
vn_fsid(struct vnode * vp,struct vattr * va)2697 vn_fsid(struct vnode *vp, struct vattr *va)
2698 {
2699 fsid_t *f;
2700
2701 f = &vp->v_mount->mnt_stat.f_fsid;
2702 va->va_fsid = (uint32_t)f->val[1];
2703 va->va_fsid <<= sizeof(f->val[1]) * NBBY;
2704 va->va_fsid += (uint32_t)f->val[0];
2705 }
2706
2707 int
vn_fsync_buf(struct vnode * vp,int waitfor)2708 vn_fsync_buf(struct vnode *vp, int waitfor)
2709 {
2710 struct buf *bp, *nbp;
2711 struct bufobj *bo;
2712 struct mount *mp;
2713 int error, maxretry;
2714
2715 error = 0;
2716 maxretry = 10000; /* large, arbitrarily chosen */
2717 mp = NULL;
2718 if (vp->v_type == VCHR) {
2719 VI_LOCK(vp);
2720 mp = vp->v_rdev->si_mountpt;
2721 VI_UNLOCK(vp);
2722 }
2723 bo = &vp->v_bufobj;
2724 BO_LOCK(bo);
2725 loop1:
2726 /*
2727 * MARK/SCAN initialization to avoid infinite loops.
2728 */
2729 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) {
2730 bp->b_vflags &= ~BV_SCANNED;
2731 bp->b_error = 0;
2732 }
2733
2734 /*
2735 * Flush all dirty buffers associated with a vnode.
2736 */
2737 loop2:
2738 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
2739 if ((bp->b_vflags & BV_SCANNED) != 0)
2740 continue;
2741 bp->b_vflags |= BV_SCANNED;
2742 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL)) {
2743 if (waitfor != MNT_WAIT)
2744 continue;
2745 if (BUF_LOCK(bp,
2746 LK_EXCLUSIVE | LK_INTERLOCK | LK_SLEEPFAIL,
2747 BO_LOCKPTR(bo)) != 0) {
2748 BO_LOCK(bo);
2749 goto loop1;
2750 }
2751 BO_LOCK(bo);
2752 }
2753 BO_UNLOCK(bo);
2754 KASSERT(bp->b_bufobj == bo,
2755 ("bp %p wrong b_bufobj %p should be %p",
2756 bp, bp->b_bufobj, bo));
2757 if ((bp->b_flags & B_DELWRI) == 0)
2758 panic("fsync: not dirty");
2759 if ((vp->v_object != NULL) && (bp->b_flags & B_CLUSTEROK)) {
2760 vfs_bio_awrite(bp);
2761 } else {
2762 bremfree(bp);
2763 bawrite(bp);
2764 }
2765 if (maxretry < 1000)
2766 pause("dirty", hz < 1000 ? 1 : hz / 1000);
2767 BO_LOCK(bo);
2768 goto loop2;
2769 }
2770
2771 /*
2772 * If synchronous the caller expects us to completely resolve all
2773 * dirty buffers in the system. Wait for in-progress I/O to
2774 * complete (which could include background bitmap writes), then
2775 * retry if dirty blocks still exist.
2776 */
2777 if (waitfor == MNT_WAIT) {
2778 bufobj_wwait(bo, 0, 0);
2779 if (bo->bo_dirty.bv_cnt > 0) {
2780 /*
2781 * If we are unable to write any of these buffers
2782 * then we fail now rather than trying endlessly
2783 * to write them out.
2784 */
2785 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs)
2786 if ((error = bp->b_error) != 0)
2787 break;
2788 if ((mp != NULL && mp->mnt_secondary_writes > 0) ||
2789 (error == 0 && --maxretry >= 0))
2790 goto loop1;
2791 if (error == 0)
2792 error = EAGAIN;
2793 }
2794 }
2795 BO_UNLOCK(bo);
2796 if (error != 0)
2797 vn_printf(vp, "fsync: giving up on dirty (error = %d) ", error);
2798
2799 return (error);
2800 }
2801
2802 /*
2803 * Copies a byte range from invp to outvp. Calls VOP_COPY_FILE_RANGE()
2804 * or vn_generic_copy_file_range() after rangelocking the byte ranges,
2805 * to do the actual copy.
2806 * vn_generic_copy_file_range() is factored out, so it can be called
2807 * from a VOP_COPY_FILE_RANGE() call as well, but handles vnodes from
2808 * different file systems.
2809 */
2810 int
vn_copy_file_range(struct vnode * invp,off_t * inoffp,struct vnode * outvp,off_t * outoffp,size_t * lenp,unsigned int flags,struct ucred * incred,struct ucred * outcred,struct thread * fsize_td)2811 vn_copy_file_range(struct vnode *invp, off_t *inoffp, struct vnode *outvp,
2812 off_t *outoffp, size_t *lenp, unsigned int flags, struct ucred *incred,
2813 struct ucred *outcred, struct thread *fsize_td)
2814 {
2815 int error;
2816 size_t len;
2817 uint64_t uval;
2818
2819 len = *lenp;
2820 *lenp = 0; /* For error returns. */
2821 error = 0;
2822
2823 /* Do some sanity checks on the arguments. */
2824 if (invp->v_type == VDIR || outvp->v_type == VDIR)
2825 error = EISDIR;
2826 else if (*inoffp < 0 || *outoffp < 0 ||
2827 invp->v_type != VREG || outvp->v_type != VREG)
2828 error = EINVAL;
2829 if (error != 0)
2830 goto out;
2831
2832 /* Ensure offset + len does not wrap around. */
2833 uval = *inoffp;
2834 uval += len;
2835 if (uval > INT64_MAX)
2836 len = INT64_MAX - *inoffp;
2837 uval = *outoffp;
2838 uval += len;
2839 if (uval > INT64_MAX)
2840 len = INT64_MAX - *outoffp;
2841 if (len == 0)
2842 goto out;
2843
2844 /*
2845 * If the two vnode are for the same file system, call
2846 * VOP_COPY_FILE_RANGE(), otherwise call vn_generic_copy_file_range()
2847 * which can handle copies across multiple file systems.
2848 */
2849 *lenp = len;
2850 if (invp->v_mount == outvp->v_mount)
2851 error = VOP_COPY_FILE_RANGE(invp, inoffp, outvp, outoffp,
2852 lenp, flags, incred, outcred, fsize_td);
2853 else
2854 error = vn_generic_copy_file_range(invp, inoffp, outvp,
2855 outoffp, lenp, flags, incred, outcred, fsize_td);
2856 out:
2857 return (error);
2858 }
2859
2860 /*
2861 * Test len bytes of data starting at dat for all bytes == 0.
2862 * Return true if all bytes are zero, false otherwise.
2863 * Expects dat to be well aligned.
2864 */
2865 static bool
mem_iszero(void * dat,int len)2866 mem_iszero(void *dat, int len)
2867 {
2868 int i;
2869 const u_int *p;
2870 const char *cp;
2871
2872 for (p = dat; len > 0; len -= sizeof(*p), p++) {
2873 if (len >= sizeof(*p)) {
2874 if (*p != 0)
2875 return (false);
2876 } else {
2877 cp = (const char *)p;
2878 for (i = 0; i < len; i++, cp++)
2879 if (*cp != '\0')
2880 return (false);
2881 }
2882 }
2883 return (true);
2884 }
2885
2886 /*
2887 * Look for a hole in the output file and, if found, adjust *outoffp
2888 * and *xferp to skip past the hole.
2889 * *xferp is the entire hole length to be written and xfer2 is how many bytes
2890 * to be written as 0's upon return.
2891 */
2892 static off_t
vn_skip_hole(struct vnode * outvp,off_t xfer2,off_t * outoffp,off_t * xferp,off_t * dataoffp,off_t * holeoffp,struct ucred * cred)2893 vn_skip_hole(struct vnode *outvp, off_t xfer2, off_t *outoffp, off_t *xferp,
2894 off_t *dataoffp, off_t *holeoffp, struct ucred *cred)
2895 {
2896 int error;
2897 off_t delta;
2898
2899 if (*holeoffp == 0 || *holeoffp <= *outoffp) {
2900 *dataoffp = *outoffp;
2901 error = VOP_IOCTL(outvp, FIOSEEKDATA, dataoffp, 0, cred,
2902 curthread);
2903 if (error == 0) {
2904 *holeoffp = *dataoffp;
2905 error = VOP_IOCTL(outvp, FIOSEEKHOLE, holeoffp, 0, cred,
2906 curthread);
2907 }
2908 if (error != 0 || *holeoffp == *dataoffp) {
2909 /*
2910 * Since outvp is unlocked, it may be possible for
2911 * another thread to do a truncate(), lseek(), write()
2912 * creating a hole at startoff between the above
2913 * VOP_IOCTL() calls, if the other thread does not do
2914 * rangelocking.
2915 * If that happens, *holeoffp == *dataoffp and finding
2916 * the hole has failed, so disable vn_skip_hole().
2917 */
2918 *holeoffp = -1; /* Disable use of vn_skip_hole(). */
2919 return (xfer2);
2920 }
2921 KASSERT(*dataoffp >= *outoffp,
2922 ("vn_skip_hole: dataoff=%jd < outoff=%jd",
2923 (intmax_t)*dataoffp, (intmax_t)*outoffp));
2924 KASSERT(*holeoffp > *dataoffp,
2925 ("vn_skip_hole: holeoff=%jd <= dataoff=%jd",
2926 (intmax_t)*holeoffp, (intmax_t)*dataoffp));
2927 }
2928
2929 /*
2930 * If there is a hole before the data starts, advance *outoffp and
2931 * *xferp past the hole.
2932 */
2933 if (*dataoffp > *outoffp) {
2934 delta = *dataoffp - *outoffp;
2935 if (delta >= *xferp) {
2936 /* Entire *xferp is a hole. */
2937 *outoffp += *xferp;
2938 *xferp = 0;
2939 return (0);
2940 }
2941 *xferp -= delta;
2942 *outoffp += delta;
2943 xfer2 = MIN(xfer2, *xferp);
2944 }
2945
2946 /*
2947 * If a hole starts before the end of this xfer2, reduce this xfer2 so
2948 * that the write ends at the start of the hole.
2949 * *holeoffp should always be greater than *outoffp, but for the
2950 * non-INVARIANTS case, check this to make sure xfer2 remains a sane
2951 * value.
2952 */
2953 if (*holeoffp > *outoffp && *holeoffp < *outoffp + xfer2)
2954 xfer2 = *holeoffp - *outoffp;
2955 return (xfer2);
2956 }
2957
2958 /*
2959 * Write an xfer sized chunk to outvp in blksize blocks from dat.
2960 * dat is a maximum of blksize in length and can be written repeatedly in
2961 * the chunk.
2962 * If growfile == true, just grow the file via vn_truncate_locked() instead
2963 * of doing actual writes.
2964 * If checkhole == true, a hole is being punched, so skip over any hole
2965 * already in the output file.
2966 */
2967 static int
vn_write_outvp(struct vnode * outvp,char * dat,off_t outoff,off_t xfer,u_long blksize,bool growfile,bool checkhole,struct ucred * cred)2968 vn_write_outvp(struct vnode *outvp, char *dat, off_t outoff, off_t xfer,
2969 u_long blksize, bool growfile, bool checkhole, struct ucred *cred)
2970 {
2971 struct mount *mp;
2972 off_t dataoff, holeoff, xfer2;
2973 int error, lckf;
2974
2975 /*
2976 * Loop around doing writes of blksize until write has been completed.
2977 * Lock/unlock on each loop iteration so that a bwillwrite() can be
2978 * done for each iteration, since the xfer argument can be very
2979 * large if there is a large hole to punch in the output file.
2980 */
2981 error = 0;
2982 holeoff = 0;
2983 do {
2984 xfer2 = MIN(xfer, blksize);
2985 if (checkhole) {
2986 /*
2987 * Punching a hole. Skip writing if there is
2988 * already a hole in the output file.
2989 */
2990 xfer2 = vn_skip_hole(outvp, xfer2, &outoff, &xfer,
2991 &dataoff, &holeoff, cred);
2992 if (xfer == 0)
2993 break;
2994 if (holeoff < 0)
2995 checkhole = false;
2996 KASSERT(xfer2 > 0, ("vn_write_outvp: xfer2=%jd",
2997 (intmax_t)xfer2));
2998 }
2999 bwillwrite();
3000 mp = NULL;
3001 error = vn_start_write(outvp, &mp, V_WAIT);
3002 if (error != 0)
3003 break;
3004 if (growfile) {
3005 error = vn_lock(outvp, LK_EXCLUSIVE);
3006 if (error == 0) {
3007 error = vn_truncate_locked(outvp, outoff + xfer,
3008 false, cred);
3009 VOP_UNLOCK(outvp);
3010 }
3011 } else {
3012 if (MNT_SHARED_WRITES(mp))
3013 lckf = LK_SHARED;
3014 else
3015 lckf = LK_EXCLUSIVE;
3016 error = vn_lock(outvp, lckf);
3017 if (error == 0) {
3018 error = vn_rdwr(UIO_WRITE, outvp, dat, xfer2,
3019 outoff, UIO_SYSSPACE, IO_NODELOCKED,
3020 curthread->td_ucred, cred, NULL, curthread);
3021 outoff += xfer2;
3022 xfer -= xfer2;
3023 VOP_UNLOCK(outvp);
3024 }
3025 }
3026 if (mp != NULL)
3027 vn_finished_write(mp);
3028 } while (!growfile && xfer > 0 && error == 0);
3029 return (error);
3030 }
3031
3032 /*
3033 * Copy a byte range of one file to another. This function can handle the
3034 * case where invp and outvp are on different file systems.
3035 * It can also be called by a VOP_COPY_FILE_RANGE() to do the work, if there
3036 * is no better file system specific way to do it.
3037 */
3038 int
vn_generic_copy_file_range(struct vnode * invp,off_t * inoffp,struct vnode * outvp,off_t * outoffp,size_t * lenp,unsigned int flags,struct ucred * incred,struct ucred * outcred,struct thread * fsize_td)3039 vn_generic_copy_file_range(struct vnode *invp, off_t *inoffp,
3040 struct vnode *outvp, off_t *outoffp, size_t *lenp, unsigned int flags,
3041 struct ucred *incred, struct ucred *outcred, struct thread *fsize_td)
3042 {
3043 struct vattr va;
3044 struct mount *mp;
3045 struct uio io;
3046 off_t startoff, endoff, xfer, xfer2;
3047 u_long blksize;
3048 int error, interrupted;
3049 bool cantseek, readzeros, eof, lastblock;
3050 ssize_t aresid;
3051 size_t copylen, len, rem, savlen;
3052 char *dat;
3053 long holein, holeout;
3054
3055 holein = holeout = 0;
3056 savlen = len = *lenp;
3057 error = 0;
3058 interrupted = 0;
3059 dat = NULL;
3060
3061 error = vn_lock(invp, LK_SHARED);
3062 if (error != 0)
3063 goto out;
3064 if (VOP_PATHCONF(invp, _PC_MIN_HOLE_SIZE, &holein) != 0)
3065 holein = 0;
3066 VOP_UNLOCK(invp);
3067
3068 mp = NULL;
3069 error = vn_start_write(outvp, &mp, V_WAIT);
3070 if (error == 0)
3071 error = vn_lock(outvp, LK_EXCLUSIVE);
3072 if (error == 0) {
3073 /*
3074 * If fsize_td != NULL, do a vn_rlimit_fsize() call,
3075 * now that outvp is locked.
3076 */
3077 if (fsize_td != NULL) {
3078 io.uio_offset = *outoffp;
3079 io.uio_resid = len;
3080 error = vn_rlimit_fsize(outvp, &io, fsize_td);
3081 if (error != 0)
3082 error = EFBIG;
3083 }
3084 if (VOP_PATHCONF(outvp, _PC_MIN_HOLE_SIZE, &holeout) != 0)
3085 holeout = 0;
3086 /*
3087 * Holes that are past EOF do not need to be written as a block
3088 * of zero bytes. So, truncate the output file as far as
3089 * possible and then use va.va_size to decide if writing 0
3090 * bytes is necessary in the loop below.
3091 */
3092 if (error == 0)
3093 error = VOP_GETATTR(outvp, &va, outcred);
3094 if (error == 0 && va.va_size > *outoffp && va.va_size <=
3095 *outoffp + len) {
3096 #ifdef MAC
3097 error = mac_vnode_check_write(curthread->td_ucred,
3098 outcred, outvp);
3099 if (error == 0)
3100 #endif
3101 error = vn_truncate_locked(outvp, *outoffp,
3102 false, outcred);
3103 if (error == 0)
3104 va.va_size = *outoffp;
3105 }
3106 VOP_UNLOCK(outvp);
3107 }
3108 if (mp != NULL)
3109 vn_finished_write(mp);
3110 if (error != 0)
3111 goto out;
3112
3113 /*
3114 * Set the blksize to the larger of the hole sizes for invp and outvp.
3115 * If hole sizes aren't available, set the blksize to the larger
3116 * f_iosize of invp and outvp.
3117 * This code expects the hole sizes and f_iosizes to be powers of 2.
3118 * This value is clipped at 4Kbytes and 1Mbyte.
3119 */
3120 blksize = MAX(holein, holeout);
3121
3122 /* Clip len to end at an exact multiple of hole size. */
3123 if (blksize > 1) {
3124 rem = *inoffp % blksize;
3125 if (rem > 0)
3126 rem = blksize - rem;
3127 if (len > rem && len - rem > blksize)
3128 len = savlen = rounddown(len - rem, blksize) + rem;
3129 }
3130
3131 if (blksize <= 1)
3132 blksize = MAX(invp->v_mount->mnt_stat.f_iosize,
3133 outvp->v_mount->mnt_stat.f_iosize);
3134 if (blksize < 4096)
3135 blksize = 4096;
3136 else if (blksize > 1024 * 1024)
3137 blksize = 1024 * 1024;
3138 dat = malloc(blksize, M_TEMP, M_WAITOK);
3139
3140 /*
3141 * If VOP_IOCTL(FIOSEEKHOLE) works for invp, use it and FIOSEEKDATA
3142 * to find holes. Otherwise, just scan the read block for all 0s
3143 * in the inner loop where the data copying is done.
3144 * Note that some file systems such as NFSv3, NFSv4.0 and NFSv4.1 may
3145 * support holes on the server, but do not support FIOSEEKHOLE.
3146 */
3147 eof = false;
3148 while (len > 0 && error == 0 && !eof && interrupted == 0) {
3149 endoff = 0; /* To shut up compilers. */
3150 cantseek = true;
3151 startoff = *inoffp;
3152 copylen = len;
3153
3154 /*
3155 * Find the next data area. If there is just a hole to EOF,
3156 * FIOSEEKDATA should fail and then we drop down into the
3157 * inner loop and create the hole on the outvp file.
3158 * (I do not know if any file system will report a hole to
3159 * EOF via FIOSEEKHOLE, but I am pretty sure FIOSEEKDATA
3160 * will fail for those file systems.)
3161 *
3162 * For input files that don't support FIOSEEKDATA/FIOSEEKHOLE,
3163 * the code just falls through to the inner copy loop.
3164 */
3165 error = EINVAL;
3166 if (holein > 0)
3167 error = VOP_IOCTL(invp, FIOSEEKDATA, &startoff, 0,
3168 incred, curthread);
3169 if (error == 0) {
3170 endoff = startoff;
3171 error = VOP_IOCTL(invp, FIOSEEKHOLE, &endoff, 0,
3172 incred, curthread);
3173 /*
3174 * Since invp is unlocked, it may be possible for
3175 * another thread to do a truncate(), lseek(), write()
3176 * creating a hole at startoff between the above
3177 * VOP_IOCTL() calls, if the other thread does not do
3178 * rangelocking.
3179 * If that happens, startoff == endoff and finding
3180 * the hole has failed, so set an error.
3181 */
3182 if (error == 0 && startoff == endoff)
3183 error = EINVAL; /* Any error. Reset to 0. */
3184 }
3185 if (error == 0) {
3186 if (startoff > *inoffp) {
3187 /* Found hole before data block. */
3188 xfer = MIN(startoff - *inoffp, len);
3189 if (*outoffp < va.va_size) {
3190 /* Must write 0s to punch hole. */
3191 xfer2 = MIN(va.va_size - *outoffp,
3192 xfer);
3193 memset(dat, 0, MIN(xfer2, blksize));
3194 error = vn_write_outvp(outvp, dat,
3195 *outoffp, xfer2, blksize, false,
3196 holeout > 0, outcred);
3197 }
3198
3199 if (error == 0 && *outoffp + xfer >
3200 va.va_size && xfer == len)
3201 /* Grow last block. */
3202 error = vn_write_outvp(outvp, dat,
3203 *outoffp, xfer, blksize, true,
3204 false, outcred);
3205 if (error == 0) {
3206 *inoffp += xfer;
3207 *outoffp += xfer;
3208 len -= xfer;
3209 if (len < savlen)
3210 interrupted = sig_intr();
3211 }
3212 }
3213 copylen = MIN(len, endoff - startoff);
3214 cantseek = false;
3215 } else {
3216 cantseek = true;
3217 startoff = *inoffp;
3218 copylen = len;
3219 error = 0;
3220 }
3221
3222 xfer = blksize;
3223 if (cantseek) {
3224 /*
3225 * Set first xfer to end at a block boundary, so that
3226 * holes are more likely detected in the loop below via
3227 * the for all bytes 0 method.
3228 */
3229 xfer -= (*inoffp % blksize);
3230 }
3231 /* Loop copying the data block. */
3232 while (copylen > 0 && error == 0 && !eof && interrupted == 0) {
3233 if (copylen < xfer)
3234 xfer = copylen;
3235 error = vn_lock(invp, LK_SHARED);
3236 if (error != 0)
3237 goto out;
3238 error = vn_rdwr(UIO_READ, invp, dat, xfer,
3239 startoff, UIO_SYSSPACE, IO_NODELOCKED,
3240 curthread->td_ucred, incred, &aresid,
3241 curthread);
3242 VOP_UNLOCK(invp);
3243 lastblock = false;
3244 if (error == 0 && aresid > 0) {
3245 /* Stop the copy at EOF on the input file. */
3246 xfer -= aresid;
3247 eof = true;
3248 lastblock = true;
3249 }
3250 if (error == 0) {
3251 /*
3252 * Skip the write for holes past the initial EOF
3253 * of the output file, unless this is the last
3254 * write of the output file at EOF.
3255 */
3256 readzeros = cantseek ? mem_iszero(dat, xfer) :
3257 false;
3258 if (xfer == len)
3259 lastblock = true;
3260 if (!cantseek || *outoffp < va.va_size ||
3261 lastblock || !readzeros)
3262 error = vn_write_outvp(outvp, dat,
3263 *outoffp, xfer, blksize,
3264 readzeros && lastblock &&
3265 *outoffp >= va.va_size, false,
3266 outcred);
3267 if (error == 0) {
3268 *inoffp += xfer;
3269 startoff += xfer;
3270 *outoffp += xfer;
3271 copylen -= xfer;
3272 len -= xfer;
3273 if (len < savlen)
3274 interrupted = sig_intr();
3275 }
3276 }
3277 xfer = blksize;
3278 }
3279 }
3280 out:
3281 *lenp = savlen - len;
3282 free(dat, M_TEMP);
3283 return (error);
3284 }
3285
3286 static int
vn_fallocate(struct file * fp,off_t offset,off_t len,struct thread * td)3287 vn_fallocate(struct file *fp, off_t offset, off_t len, struct thread *td)
3288 {
3289 struct mount *mp;
3290 struct vnode *vp;
3291 off_t olen, ooffset;
3292 int error;
3293 #ifdef AUDIT
3294 int audited_vnode1 = 0;
3295 #endif
3296
3297 vp = fp->f_vnode;
3298 if (vp->v_type != VREG)
3299 return (ENODEV);
3300
3301 /* Allocating blocks may take a long time, so iterate. */
3302 for (;;) {
3303 olen = len;
3304 ooffset = offset;
3305
3306 bwillwrite();
3307 mp = NULL;
3308 error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
3309 if (error != 0)
3310 break;
3311 error = vn_lock(vp, LK_EXCLUSIVE);
3312 if (error != 0) {
3313 vn_finished_write(mp);
3314 break;
3315 }
3316 #ifdef AUDIT
3317 if (!audited_vnode1) {
3318 AUDIT_ARG_VNODE1(vp);
3319 audited_vnode1 = 1;
3320 }
3321 #endif
3322 #ifdef MAC
3323 error = mac_vnode_check_write(td->td_ucred, fp->f_cred, vp);
3324 if (error == 0)
3325 #endif
3326 error = VOP_ALLOCATE(vp, &offset, &len);
3327 VOP_UNLOCK(vp);
3328 vn_finished_write(mp);
3329
3330 if (olen + ooffset != offset + len) {
3331 panic("offset + len changed from %jx/%jx to %jx/%jx",
3332 ooffset, olen, offset, len);
3333 }
3334 if (error != 0 || len == 0)
3335 break;
3336 KASSERT(olen > len, ("Iteration did not make progress?"));
3337 maybe_yield();
3338 }
3339
3340 return (error);
3341 }
3342
3343 static u_long vn_lock_pair_pause_cnt;
3344 SYSCTL_ULONG(_debug, OID_AUTO, vn_lock_pair_pause, CTLFLAG_RD,
3345 &vn_lock_pair_pause_cnt, 0,
3346 "Count of vn_lock_pair deadlocks");
3347
3348 u_int vn_lock_pair_pause_max;
3349 SYSCTL_UINT(_debug, OID_AUTO, vn_lock_pair_pause_max, CTLFLAG_RW,
3350 &vn_lock_pair_pause_max, 0,
3351 "Max ticks for vn_lock_pair deadlock avoidance sleep");
3352
3353 static void
vn_lock_pair_pause(const char * wmesg)3354 vn_lock_pair_pause(const char *wmesg)
3355 {
3356 atomic_add_long(&vn_lock_pair_pause_cnt, 1);
3357 pause(wmesg, prng32_bounded(vn_lock_pair_pause_max));
3358 }
3359
3360 /*
3361 * Lock pair of vnodes vp1, vp2, avoiding lock order reversal.
3362 * vp1_locked indicates whether vp1 is exclusively locked; if not, vp1
3363 * must be unlocked. Same for vp2 and vp2_locked. One of the vnodes
3364 * can be NULL.
3365 *
3366 * The function returns with both vnodes exclusively locked, and
3367 * guarantees that it does not create lock order reversal with other
3368 * threads during its execution. Both vnodes could be unlocked
3369 * temporary (and reclaimed).
3370 */
3371 void
vn_lock_pair(struct vnode * vp1,bool vp1_locked,struct vnode * vp2,bool vp2_locked)3372 vn_lock_pair(struct vnode *vp1, bool vp1_locked, struct vnode *vp2,
3373 bool vp2_locked)
3374 {
3375 int error;
3376
3377 if (vp1 == NULL && vp2 == NULL)
3378 return;
3379 if (vp1 != NULL) {
3380 if (vp1_locked)
3381 ASSERT_VOP_ELOCKED(vp1, "vp1");
3382 else
3383 ASSERT_VOP_UNLOCKED(vp1, "vp1");
3384 } else {
3385 vp1_locked = true;
3386 }
3387 if (vp2 != NULL) {
3388 if (vp2_locked)
3389 ASSERT_VOP_ELOCKED(vp2, "vp2");
3390 else
3391 ASSERT_VOP_UNLOCKED(vp2, "vp2");
3392 } else {
3393 vp2_locked = true;
3394 }
3395 if (!vp1_locked && !vp2_locked) {
3396 vn_lock(vp1, LK_EXCLUSIVE | LK_RETRY);
3397 vp1_locked = true;
3398 }
3399
3400 for (;;) {
3401 if (vp1_locked && vp2_locked)
3402 break;
3403 if (vp1_locked && vp2 != NULL) {
3404 if (vp1 != NULL) {
3405 error = VOP_LOCK1(vp2, LK_EXCLUSIVE | LK_NOWAIT,
3406 __FILE__, __LINE__);
3407 if (error == 0)
3408 break;
3409 VOP_UNLOCK(vp1);
3410 vp1_locked = false;
3411 vn_lock_pair_pause("vlp1");
3412 }
3413 vn_lock(vp2, LK_EXCLUSIVE | LK_RETRY);
3414 vp2_locked = true;
3415 }
3416 if (vp2_locked && vp1 != NULL) {
3417 if (vp2 != NULL) {
3418 error = VOP_LOCK1(vp1, LK_EXCLUSIVE | LK_NOWAIT,
3419 __FILE__, __LINE__);
3420 if (error == 0)
3421 break;
3422 VOP_UNLOCK(vp2);
3423 vp2_locked = false;
3424 vn_lock_pair_pause("vlp2");
3425 }
3426 vn_lock(vp1, LK_EXCLUSIVE | LK_RETRY);
3427 vp1_locked = true;
3428 }
3429 }
3430 if (vp1 != NULL)
3431 ASSERT_VOP_ELOCKED(vp1, "vp1 ret");
3432 if (vp2 != NULL)
3433 ASSERT_VOP_ELOCKED(vp2, "vp2 ret");
3434 }
3435