1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
13 * Copyright (c) 2013, 2014 The FreeBSD Foundation
14 *
15 * Portions of this software were developed by Konstantin Belousov
16 * under sponsorship from the FreeBSD Foundation.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
20 * are met:
21 * 1. Redistributions of source code must retain the above copyright
22 * notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 * notice, this list of conditions and the following disclaimer in the
25 * documentation and/or other materials provided with the distribution.
26 * 3. Neither the name of the University nor the names of its contributors
27 * may be used to endorse or promote products derived from this software
28 * without specific prior written permission.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
40 * SUCH DAMAGE.
41 */
42
43 #include <sys/cdefs.h>
44 #include "opt_hwpmc_hooks.h"
45
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/disk.h>
49 #include <sys/fail.h>
50 #include <sys/fcntl.h>
51 #include <sys/file.h>
52 #include <sys/kdb.h>
53 #include <sys/ktr.h>
54 #include <sys/stat.h>
55 #include <sys/priv.h>
56 #include <sys/proc.h>
57 #include <sys/limits.h>
58 #include <sys/lock.h>
59 #include <sys/mman.h>
60 #include <sys/mount.h>
61 #include <sys/mutex.h>
62 #include <sys/namei.h>
63 #include <sys/vnode.h>
64 #include <sys/dirent.h>
65 #include <sys/bio.h>
66 #include <sys/buf.h>
67 #include <sys/filio.h>
68 #include <sys/resourcevar.h>
69 #include <sys/rwlock.h>
70 #include <sys/prng.h>
71 #include <sys/sx.h>
72 #include <sys/sleepqueue.h>
73 #include <sys/sysctl.h>
74 #include <sys/ttycom.h>
75 #include <sys/conf.h>
76 #include <sys/syslog.h>
77 #include <sys/unistd.h>
78 #include <sys/user.h>
79 #include <sys/ktrace.h>
80
81 #include <security/audit/audit.h>
82 #include <security/mac/mac_framework.h>
83
84 #include <vm/vm.h>
85 #include <vm/vm_extern.h>
86 #include <vm/pmap.h>
87 #include <vm/vm_map.h>
88 #include <vm/vm_object.h>
89 #include <vm/vm_page.h>
90 #include <vm/vm_pager.h>
91 #include <vm/vnode_pager.h>
92
93 #ifdef HWPMC_HOOKS
94 #include <sys/pmckern.h>
95 #endif
96
97 static fo_rdwr_t vn_read;
98 static fo_rdwr_t vn_write;
99 static fo_rdwr_t vn_io_fault;
100 static fo_truncate_t vn_truncate;
101 static fo_ioctl_t vn_ioctl;
102 static fo_poll_t vn_poll;
103 static fo_kqfilter_t vn_kqfilter;
104 static fo_close_t vn_closefile;
105 static fo_mmap_t vn_mmap;
106 static fo_fallocate_t vn_fallocate;
107 static fo_fspacectl_t vn_fspacectl;
108
109 struct fileops vnops = {
110 .fo_read = vn_io_fault,
111 .fo_write = vn_io_fault,
112 .fo_truncate = vn_truncate,
113 .fo_ioctl = vn_ioctl,
114 .fo_poll = vn_poll,
115 .fo_kqfilter = vn_kqfilter,
116 .fo_stat = vn_statfile,
117 .fo_close = vn_closefile,
118 .fo_chmod = vn_chmod,
119 .fo_chown = vn_chown,
120 .fo_sendfile = vn_sendfile,
121 .fo_seek = vn_seek,
122 .fo_fill_kinfo = vn_fill_kinfo,
123 .fo_mmap = vn_mmap,
124 .fo_fallocate = vn_fallocate,
125 .fo_fspacectl = vn_fspacectl,
126 .fo_cmp = vn_cmp,
127 .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE
128 };
129
130 const u_int io_hold_cnt = 16;
131 static int vn_io_fault_enable = 1;
132 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RWTUN,
133 &vn_io_fault_enable, 0, "Enable vn_io_fault lock avoidance");
134 static int vn_io_fault_prefault = 0;
135 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_prefault, CTLFLAG_RWTUN,
136 &vn_io_fault_prefault, 0, "Enable vn_io_fault prefaulting");
137 static int vn_io_pgcache_read_enable = 1;
138 SYSCTL_INT(_debug, OID_AUTO, vn_io_pgcache_read_enable, CTLFLAG_RWTUN,
139 &vn_io_pgcache_read_enable, 0,
140 "Enable copying from page cache for reads, avoiding fs");
141 static u_long vn_io_faults_cnt;
142 SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD,
143 &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers");
144
145 static int vfs_allow_read_dir = 0;
146 SYSCTL_INT(_security_bsd, OID_AUTO, allow_read_dir, CTLFLAG_RW,
147 &vfs_allow_read_dir, 0,
148 "Enable read(2) of directory by root for filesystems that support it");
149
150 /*
151 * Returns true if vn_io_fault mode of handling the i/o request should
152 * be used.
153 */
154 static bool
do_vn_io_fault(struct vnode * vp,struct uio * uio)155 do_vn_io_fault(struct vnode *vp, struct uio *uio)
156 {
157 struct mount *mp;
158
159 return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG &&
160 (mp = vp->v_mount) != NULL &&
161 (mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable);
162 }
163
164 /*
165 * Structure used to pass arguments to vn_io_fault1(), to do either
166 * file- or vnode-based I/O calls.
167 */
168 struct vn_io_fault_args {
169 enum {
170 VN_IO_FAULT_FOP,
171 VN_IO_FAULT_VOP
172 } kind;
173 struct ucred *cred;
174 int flags;
175 union {
176 struct fop_args_tag {
177 struct file *fp;
178 fo_rdwr_t *doio;
179 } fop_args;
180 struct vop_args_tag {
181 struct vnode *vp;
182 } vop_args;
183 } args;
184 };
185
186 static int vn_io_fault1(struct vnode *vp, struct uio *uio,
187 struct vn_io_fault_args *args, struct thread *td);
188
189 int
vn_open(struct nameidata * ndp,int * flagp,int cmode,struct file * fp)190 vn_open(struct nameidata *ndp, int *flagp, int cmode, struct file *fp)
191 {
192 struct thread *td = curthread;
193
194 return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp));
195 }
196
197 static uint64_t
open2nameif(int fmode,u_int vn_open_flags)198 open2nameif(int fmode, u_int vn_open_flags)
199 {
200 uint64_t res;
201
202 res = ISOPEN | LOCKLEAF;
203 if ((fmode & O_RESOLVE_BENEATH) != 0)
204 res |= RBENEATH;
205 if ((fmode & O_EMPTY_PATH) != 0)
206 res |= EMPTYPATH;
207 if ((fmode & FREAD) != 0)
208 res |= OPENREAD;
209 if ((fmode & FWRITE) != 0)
210 res |= OPENWRITE;
211 if ((vn_open_flags & VN_OPEN_NOAUDIT) == 0)
212 res |= AUDITVNODE1;
213 if ((vn_open_flags & VN_OPEN_NOCAPCHECK) != 0)
214 res |= NOCAPCHECK;
215 if ((vn_open_flags & VN_OPEN_WANTIOCTLCAPS) != 0)
216 res |= WANTIOCTLCAPS;
217 return (res);
218 }
219
220 /*
221 * Common code for vnode open operations via a name lookup.
222 * Lookup the vnode and invoke VOP_CREATE if needed.
223 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine.
224 *
225 * Note that this does NOT free nameidata for the successful case,
226 * due to the NDINIT being done elsewhere.
227 */
228 int
vn_open_cred(struct nameidata * ndp,int * flagp,int cmode,u_int vn_open_flags,struct ucred * cred,struct file * fp)229 vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags,
230 struct ucred *cred, struct file *fp)
231 {
232 struct vnode *vp;
233 struct mount *mp;
234 struct vattr vat;
235 struct vattr *vap = &vat;
236 int fmode, error;
237 bool first_open;
238
239 restart:
240 first_open = false;
241 fmode = *flagp;
242 if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT |
243 O_EXCL | O_DIRECTORY) ||
244 (fmode & (O_CREAT | O_EMPTY_PATH)) == (O_CREAT | O_EMPTY_PATH))
245 return (EINVAL);
246 else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) {
247 ndp->ni_cnd.cn_nameiop = CREATE;
248 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags);
249 /*
250 * Set NOCACHE to avoid flushing the cache when
251 * rolling in many files at once.
252 *
253 * Set NC_KEEPPOSENTRY to keep positive entries if they already
254 * exist despite NOCACHE.
255 */
256 ndp->ni_cnd.cn_flags |= LOCKPARENT | NOCACHE | NC_KEEPPOSENTRY;
257 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0)
258 ndp->ni_cnd.cn_flags |= FOLLOW;
259 if ((vn_open_flags & VN_OPEN_INVFS) == 0)
260 bwillwrite();
261 if ((error = namei(ndp)) != 0)
262 return (error);
263 if (ndp->ni_vp == NULL) {
264 VATTR_NULL(vap);
265 vap->va_type = VREG;
266 vap->va_mode = cmode;
267 if (fmode & O_EXCL)
268 vap->va_vaflags |= VA_EXCLUSIVE;
269 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) {
270 NDFREE_PNBUF(ndp);
271 vput(ndp->ni_dvp);
272 if ((error = vn_start_write(NULL, &mp,
273 V_XSLEEP | V_PCATCH)) != 0)
274 return (error);
275 NDREINIT(ndp);
276 goto restart;
277 }
278 if ((vn_open_flags & VN_OPEN_NAMECACHE) != 0)
279 ndp->ni_cnd.cn_flags |= MAKEENTRY;
280 #ifdef MAC
281 error = mac_vnode_check_create(cred, ndp->ni_dvp,
282 &ndp->ni_cnd, vap);
283 if (error == 0)
284 #endif
285 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp,
286 &ndp->ni_cnd, vap);
287 vp = ndp->ni_vp;
288 if (error == 0 && (fmode & O_EXCL) != 0 &&
289 (fmode & (O_EXLOCK | O_SHLOCK)) != 0) {
290 VI_LOCK(vp);
291 vp->v_iflag |= VI_FOPENING;
292 VI_UNLOCK(vp);
293 first_open = true;
294 }
295 VOP_VPUT_PAIR(ndp->ni_dvp, error == 0 ? &vp : NULL,
296 false);
297 vn_finished_write(mp);
298 if (error) {
299 NDFREE_PNBUF(ndp);
300 if (error == ERELOOKUP) {
301 NDREINIT(ndp);
302 goto restart;
303 }
304 return (error);
305 }
306 fmode &= ~O_TRUNC;
307 } else {
308 if (ndp->ni_dvp == ndp->ni_vp)
309 vrele(ndp->ni_dvp);
310 else
311 vput(ndp->ni_dvp);
312 ndp->ni_dvp = NULL;
313 vp = ndp->ni_vp;
314 if (fmode & O_EXCL) {
315 error = EEXIST;
316 goto bad;
317 }
318 if (vp->v_type == VDIR) {
319 error = EISDIR;
320 goto bad;
321 }
322 fmode &= ~O_CREAT;
323 }
324 } else {
325 ndp->ni_cnd.cn_nameiop = LOOKUP;
326 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags);
327 ndp->ni_cnd.cn_flags |= (fmode & O_NOFOLLOW) != 0 ? NOFOLLOW :
328 FOLLOW;
329 if ((fmode & FWRITE) == 0)
330 ndp->ni_cnd.cn_flags |= LOCKSHARED;
331 if ((error = namei(ndp)) != 0)
332 return (error);
333 vp = ndp->ni_vp;
334 }
335 error = vn_open_vnode(vp, fmode, cred, curthread, fp);
336 if (first_open) {
337 VI_LOCK(vp);
338 vp->v_iflag &= ~VI_FOPENING;
339 wakeup(vp);
340 VI_UNLOCK(vp);
341 }
342 if (error)
343 goto bad;
344 *flagp = fmode;
345 return (0);
346 bad:
347 NDFREE_PNBUF(ndp);
348 vput(vp);
349 *flagp = fmode;
350 ndp->ni_vp = NULL;
351 return (error);
352 }
353
354 static int
vn_open_vnode_advlock(struct vnode * vp,int fmode,struct file * fp)355 vn_open_vnode_advlock(struct vnode *vp, int fmode, struct file *fp)
356 {
357 struct flock lf;
358 int error, lock_flags, type;
359
360 ASSERT_VOP_LOCKED(vp, "vn_open_vnode_advlock");
361 if ((fmode & (O_EXLOCK | O_SHLOCK)) == 0)
362 return (0);
363 KASSERT(fp != NULL, ("open with flock requires fp"));
364 if (fp->f_type != DTYPE_NONE && fp->f_type != DTYPE_VNODE)
365 return (EOPNOTSUPP);
366
367 lock_flags = VOP_ISLOCKED(vp);
368 VOP_UNLOCK(vp);
369
370 lf.l_whence = SEEK_SET;
371 lf.l_start = 0;
372 lf.l_len = 0;
373 lf.l_type = (fmode & O_EXLOCK) != 0 ? F_WRLCK : F_RDLCK;
374 type = F_FLOCK;
375 if ((fmode & FNONBLOCK) == 0)
376 type |= F_WAIT;
377 if ((fmode & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
378 type |= F_FIRSTOPEN;
379 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type);
380 if (error == 0)
381 fp->f_flag |= FHASLOCK;
382
383 vn_lock(vp, lock_flags | LK_RETRY);
384 return (error);
385 }
386
387 /*
388 * Common code for vnode open operations once a vnode is located.
389 * Check permissions, and call the VOP_OPEN routine.
390 */
391 int
vn_open_vnode(struct vnode * vp,int fmode,struct ucred * cred,struct thread * td,struct file * fp)392 vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred,
393 struct thread *td, struct file *fp)
394 {
395 accmode_t accmode;
396 int error;
397
398 if (vp->v_type == VLNK) {
399 if ((fmode & O_PATH) == 0 || (fmode & FEXEC) != 0)
400 return (EMLINK);
401 }
402 if (vp->v_type != VDIR && fmode & O_DIRECTORY)
403 return (ENOTDIR);
404
405 accmode = 0;
406 if ((fmode & O_PATH) == 0) {
407 if (vp->v_type == VSOCK)
408 return (EOPNOTSUPP);
409 if ((fmode & (FWRITE | O_TRUNC)) != 0) {
410 if (vp->v_type == VDIR)
411 return (EISDIR);
412 accmode |= VWRITE;
413 }
414 if ((fmode & FREAD) != 0)
415 accmode |= VREAD;
416 if ((fmode & O_APPEND) && (fmode & FWRITE))
417 accmode |= VAPPEND;
418 #ifdef MAC
419 if ((fmode & O_CREAT) != 0)
420 accmode |= VCREAT;
421 #endif
422 }
423 if ((fmode & FEXEC) != 0)
424 accmode |= VEXEC;
425 #ifdef MAC
426 if ((fmode & O_VERIFY) != 0)
427 accmode |= VVERIFY;
428 error = mac_vnode_check_open(cred, vp, accmode);
429 if (error != 0)
430 return (error);
431
432 accmode &= ~(VCREAT | VVERIFY);
433 #endif
434 if ((fmode & O_CREAT) == 0 && accmode != 0) {
435 error = VOP_ACCESS(vp, accmode, cred, td);
436 if (error != 0)
437 return (error);
438 }
439 if ((fmode & O_PATH) != 0) {
440 if (vp->v_type != VFIFO && vp->v_type != VSOCK &&
441 VOP_ACCESS(vp, VREAD, cred, td) == 0)
442 fp->f_flag |= FKQALLOWED;
443 return (0);
444 }
445
446 if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
447 vn_lock(vp, LK_UPGRADE | LK_RETRY);
448 error = VOP_OPEN(vp, fmode, cred, td, fp);
449 if (error != 0)
450 return (error);
451
452 error = vn_open_vnode_advlock(vp, fmode, fp);
453 if (error == 0 && (fmode & FWRITE) != 0) {
454 error = VOP_ADD_WRITECOUNT(vp, 1);
455 if (error == 0) {
456 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d",
457 __func__, vp, vp->v_writecount);
458 }
459 }
460
461 /*
462 * Error from advlock or VOP_ADD_WRITECOUNT() still requires
463 * calling VOP_CLOSE() to pair with earlier VOP_OPEN().
464 */
465 if (error != 0) {
466 if (fp != NULL) {
467 /*
468 * Arrange the call by having fdrop() to use
469 * vn_closefile(). This is to satisfy
470 * filesystems like devfs or tmpfs, which
471 * override fo_close().
472 */
473 fp->f_flag |= FOPENFAILED;
474 fp->f_vnode = vp;
475 if (fp->f_ops == &badfileops) {
476 fp->f_type = DTYPE_VNODE;
477 fp->f_ops = &vnops;
478 }
479 vref(vp);
480 } else {
481 /*
482 * If there is no fp, due to kernel-mode open,
483 * we can call VOP_CLOSE() now.
484 */
485 if ((vp->v_type == VFIFO ||
486 !MNT_EXTENDED_SHARED(vp->v_mount)) &&
487 VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
488 vn_lock(vp, LK_UPGRADE | LK_RETRY);
489 (void)VOP_CLOSE(vp, fmode & (FREAD | FWRITE | FEXEC),
490 cred, td);
491 }
492 }
493
494 ASSERT_VOP_LOCKED(vp, "vn_open_vnode");
495 return (error);
496
497 }
498
499 /*
500 * Check for write permissions on the specified vnode.
501 * Prototype text segments cannot be written.
502 * It is racy.
503 */
504 int
vn_writechk(struct vnode * vp)505 vn_writechk(struct vnode *vp)
506 {
507
508 ASSERT_VOP_LOCKED(vp, "vn_writechk");
509 /*
510 * If there's shared text associated with
511 * the vnode, try to free it up once. If
512 * we fail, we can't allow writing.
513 */
514 if (VOP_IS_TEXT(vp))
515 return (ETXTBSY);
516
517 return (0);
518 }
519
520 /*
521 * Vnode close call
522 */
523 static int
vn_close1(struct vnode * vp,int flags,struct ucred * file_cred,struct thread * td,bool keep_ref)524 vn_close1(struct vnode *vp, int flags, struct ucred *file_cred,
525 struct thread *td, bool keep_ref)
526 {
527 struct mount *mp;
528 int error, lock_flags;
529
530 lock_flags = vp->v_type != VFIFO && MNT_EXTENDED_SHARED(vp->v_mount) ?
531 LK_SHARED : LK_EXCLUSIVE;
532
533 vn_start_write(vp, &mp, V_WAIT);
534 vn_lock(vp, lock_flags | LK_RETRY);
535 AUDIT_ARG_VNODE1(vp);
536 if ((flags & (FWRITE | FOPENFAILED)) == FWRITE) {
537 VOP_ADD_WRITECOUNT_CHECKED(vp, -1);
538 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
539 __func__, vp, vp->v_writecount);
540 }
541 error = VOP_CLOSE(vp, flags, file_cred, td);
542 if (keep_ref)
543 VOP_UNLOCK(vp);
544 else
545 vput(vp);
546 vn_finished_write(mp);
547 return (error);
548 }
549
550 int
vn_close(struct vnode * vp,int flags,struct ucred * file_cred,struct thread * td)551 vn_close(struct vnode *vp, int flags, struct ucred *file_cred,
552 struct thread *td)
553 {
554
555 return (vn_close1(vp, flags, file_cred, td, false));
556 }
557
558 /*
559 * Heuristic to detect sequential operation.
560 */
561 static int
sequential_heuristic(struct uio * uio,struct file * fp)562 sequential_heuristic(struct uio *uio, struct file *fp)
563 {
564 enum uio_rw rw;
565
566 ASSERT_VOP_LOCKED(fp->f_vnode, __func__);
567
568 rw = uio->uio_rw;
569 if (fp->f_flag & FRDAHEAD)
570 return (fp->f_seqcount[rw] << IO_SEQSHIFT);
571
572 /*
573 * Offset 0 is handled specially. open() sets f_seqcount to 1 so
574 * that the first I/O is normally considered to be slightly
575 * sequential. Seeking to offset 0 doesn't change sequentiality
576 * unless previous seeks have reduced f_seqcount to 0, in which
577 * case offset 0 is not special.
578 */
579 if ((uio->uio_offset == 0 && fp->f_seqcount[rw] > 0) ||
580 uio->uio_offset == fp->f_nextoff[rw]) {
581 /*
582 * f_seqcount is in units of fixed-size blocks so that it
583 * depends mainly on the amount of sequential I/O and not
584 * much on the number of sequential I/O's. The fixed size
585 * of 16384 is hard-coded here since it is (not quite) just
586 * a magic size that works well here. This size is more
587 * closely related to the best I/O size for real disks than
588 * to any block size used by software.
589 */
590 if (uio->uio_resid >= IO_SEQMAX * 16384)
591 fp->f_seqcount[rw] = IO_SEQMAX;
592 else {
593 fp->f_seqcount[rw] += howmany(uio->uio_resid, 16384);
594 if (fp->f_seqcount[rw] > IO_SEQMAX)
595 fp->f_seqcount[rw] = IO_SEQMAX;
596 }
597 return (fp->f_seqcount[rw] << IO_SEQSHIFT);
598 }
599
600 /* Not sequential. Quickly draw-down sequentiality. */
601 if (fp->f_seqcount[rw] > 1)
602 fp->f_seqcount[rw] = 1;
603 else
604 fp->f_seqcount[rw] = 0;
605 return (0);
606 }
607
608 /*
609 * Package up an I/O request on a vnode into a uio and do it.
610 */
611 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)612 vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset,
613 enum uio_seg segflg, int ioflg, struct ucred *active_cred,
614 struct ucred *file_cred, ssize_t *aresid, struct thread *td)
615 {
616 struct uio auio;
617 struct iovec aiov;
618 struct mount *mp;
619 struct ucred *cred;
620 void *rl_cookie;
621 struct vn_io_fault_args args;
622 int error, lock_flags;
623
624 if (offset < 0 && vp->v_type != VCHR)
625 return (EINVAL);
626 auio.uio_iov = &aiov;
627 auio.uio_iovcnt = 1;
628 aiov.iov_base = base;
629 aiov.iov_len = len;
630 auio.uio_resid = len;
631 auio.uio_offset = offset;
632 auio.uio_segflg = segflg;
633 auio.uio_rw = rw;
634 auio.uio_td = td;
635 error = 0;
636
637 if ((ioflg & IO_NODELOCKED) == 0) {
638 if ((ioflg & IO_RANGELOCKED) == 0) {
639 if (rw == UIO_READ) {
640 rl_cookie = vn_rangelock_rlock(vp, offset,
641 offset + len);
642 } else if ((ioflg & IO_APPEND) != 0) {
643 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
644 } else {
645 rl_cookie = vn_rangelock_wlock(vp, offset,
646 offset + len);
647 }
648 } else
649 rl_cookie = NULL;
650 mp = NULL;
651 if (rw == UIO_WRITE) {
652 if (vp->v_type != VCHR &&
653 (error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH))
654 != 0)
655 goto out;
656 lock_flags = vn_lktype_write(mp, vp);
657 } else
658 lock_flags = LK_SHARED;
659 vn_lock(vp, lock_flags | LK_RETRY);
660 } else
661 rl_cookie = NULL;
662
663 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
664 #ifdef MAC
665 if ((ioflg & IO_NOMACCHECK) == 0) {
666 if (rw == UIO_READ)
667 error = mac_vnode_check_read(active_cred, file_cred,
668 vp);
669 else
670 error = mac_vnode_check_write(active_cred, file_cred,
671 vp);
672 }
673 #endif
674 if (error == 0) {
675 if (file_cred != NULL)
676 cred = file_cred;
677 else
678 cred = active_cred;
679 if (do_vn_io_fault(vp, &auio)) {
680 args.kind = VN_IO_FAULT_VOP;
681 args.cred = cred;
682 args.flags = ioflg;
683 args.args.vop_args.vp = vp;
684 error = vn_io_fault1(vp, &auio, &args, td);
685 } else if (rw == UIO_READ) {
686 error = VOP_READ(vp, &auio, ioflg, cred);
687 } else /* if (rw == UIO_WRITE) */ {
688 error = VOP_WRITE(vp, &auio, ioflg, cred);
689 }
690 }
691 if (aresid)
692 *aresid = auio.uio_resid;
693 else
694 if (auio.uio_resid && error == 0)
695 error = EIO;
696 if ((ioflg & IO_NODELOCKED) == 0) {
697 VOP_UNLOCK(vp);
698 if (mp != NULL)
699 vn_finished_write(mp);
700 }
701 out:
702 if (rl_cookie != NULL)
703 vn_rangelock_unlock(vp, rl_cookie);
704 return (error);
705 }
706
707 /*
708 * Package up an I/O request on a vnode into a uio and do it. The I/O
709 * request is split up into smaller chunks and we try to avoid saturating
710 * the buffer cache while potentially holding a vnode locked, so we
711 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield()
712 * to give other processes a chance to lock the vnode (either other processes
713 * core'ing the same binary, or unrelated processes scanning the directory).
714 */
715 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)716 vn_rdwr_inchunks(enum uio_rw rw, struct vnode *vp, void *base, size_t len,
717 off_t offset, enum uio_seg segflg, int ioflg, struct ucred *active_cred,
718 struct ucred *file_cred, size_t *aresid, struct thread *td)
719 {
720 int error = 0;
721 ssize_t iaresid;
722
723 do {
724 int chunk;
725
726 /*
727 * Force `offset' to a multiple of MAXBSIZE except possibly
728 * for the first chunk, so that filesystems only need to
729 * write full blocks except possibly for the first and last
730 * chunks.
731 */
732 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE;
733
734 if (chunk > len)
735 chunk = len;
736 if (rw != UIO_READ && vp->v_type == VREG)
737 bwillwrite();
738 iaresid = 0;
739 error = vn_rdwr(rw, vp, base, chunk, offset, segflg,
740 ioflg, active_cred, file_cred, &iaresid, td);
741 len -= chunk; /* aresid calc already includes length */
742 if (error)
743 break;
744 offset += chunk;
745 base = (char *)base + chunk;
746 kern_yield(PRI_USER);
747 } while (len);
748 if (aresid)
749 *aresid = len + iaresid;
750 return (error);
751 }
752
753 #if OFF_MAX <= LONG_MAX
754 off_t
foffset_lock(struct file * fp,int flags)755 foffset_lock(struct file *fp, int flags)
756 {
757 volatile short *flagsp;
758 off_t res;
759 short state;
760
761 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
762
763 if ((flags & FOF_NOLOCK) != 0)
764 return (atomic_load_long(&fp->f_offset));
765
766 /*
767 * According to McKusick the vn lock was protecting f_offset here.
768 * It is now protected by the FOFFSET_LOCKED flag.
769 */
770 flagsp = &fp->f_vnread_flags;
771 if (atomic_cmpset_acq_16(flagsp, 0, FOFFSET_LOCKED))
772 return (atomic_load_long(&fp->f_offset));
773
774 sleepq_lock(&fp->f_vnread_flags);
775 state = atomic_load_16(flagsp);
776 for (;;) {
777 if ((state & FOFFSET_LOCKED) == 0) {
778 if (!atomic_fcmpset_acq_16(flagsp, &state,
779 FOFFSET_LOCKED))
780 continue;
781 break;
782 }
783 if ((state & FOFFSET_LOCK_WAITING) == 0) {
784 if (!atomic_fcmpset_acq_16(flagsp, &state,
785 state | FOFFSET_LOCK_WAITING))
786 continue;
787 }
788 DROP_GIANT();
789 sleepq_add(&fp->f_vnread_flags, NULL, "vofflock", 0, 0);
790 sleepq_wait(&fp->f_vnread_flags, PUSER -1);
791 PICKUP_GIANT();
792 sleepq_lock(&fp->f_vnread_flags);
793 state = atomic_load_16(flagsp);
794 }
795 res = atomic_load_long(&fp->f_offset);
796 sleepq_release(&fp->f_vnread_flags);
797 return (res);
798 }
799
800 void
foffset_unlock(struct file * fp,off_t val,int flags)801 foffset_unlock(struct file *fp, off_t val, int flags)
802 {
803 volatile short *flagsp;
804 short state;
805
806 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
807
808 if ((flags & FOF_NOUPDATE) == 0)
809 atomic_store_long(&fp->f_offset, val);
810 if ((flags & FOF_NEXTOFF_R) != 0)
811 fp->f_nextoff[UIO_READ] = val;
812 if ((flags & FOF_NEXTOFF_W) != 0)
813 fp->f_nextoff[UIO_WRITE] = val;
814
815 if ((flags & FOF_NOLOCK) != 0)
816 return;
817
818 flagsp = &fp->f_vnread_flags;
819 state = atomic_load_16(flagsp);
820 if ((state & FOFFSET_LOCK_WAITING) == 0 &&
821 atomic_cmpset_rel_16(flagsp, state, 0))
822 return;
823
824 sleepq_lock(&fp->f_vnread_flags);
825 MPASS((fp->f_vnread_flags & FOFFSET_LOCKED) != 0);
826 MPASS((fp->f_vnread_flags & FOFFSET_LOCK_WAITING) != 0);
827 fp->f_vnread_flags = 0;
828 sleepq_broadcast(&fp->f_vnread_flags, SLEEPQ_SLEEP, 0, 0);
829 sleepq_release(&fp->f_vnread_flags);
830 }
831
832 static off_t
foffset_read(struct file * fp)833 foffset_read(struct file *fp)
834 {
835
836 return (atomic_load_long(&fp->f_offset));
837 }
838 #else
839 off_t
foffset_lock(struct file * fp,int flags)840 foffset_lock(struct file *fp, int flags)
841 {
842 struct mtx *mtxp;
843 off_t res;
844
845 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
846
847 mtxp = mtx_pool_find(mtxpool_sleep, fp);
848 mtx_lock(mtxp);
849 if ((flags & FOF_NOLOCK) == 0) {
850 while (fp->f_vnread_flags & FOFFSET_LOCKED) {
851 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING;
852 msleep(&fp->f_vnread_flags, mtxp, PUSER -1,
853 "vofflock", 0);
854 }
855 fp->f_vnread_flags |= FOFFSET_LOCKED;
856 }
857 res = fp->f_offset;
858 mtx_unlock(mtxp);
859 return (res);
860 }
861
862 void
foffset_unlock(struct file * fp,off_t val,int flags)863 foffset_unlock(struct file *fp, off_t val, int flags)
864 {
865 struct mtx *mtxp;
866
867 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
868
869 mtxp = mtx_pool_find(mtxpool_sleep, fp);
870 mtx_lock(mtxp);
871 if ((flags & FOF_NOUPDATE) == 0)
872 fp->f_offset = val;
873 if ((flags & FOF_NEXTOFF_R) != 0)
874 fp->f_nextoff[UIO_READ] = val;
875 if ((flags & FOF_NEXTOFF_W) != 0)
876 fp->f_nextoff[UIO_WRITE] = val;
877 if ((flags & FOF_NOLOCK) == 0) {
878 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0,
879 ("Lost FOFFSET_LOCKED"));
880 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING)
881 wakeup(&fp->f_vnread_flags);
882 fp->f_vnread_flags = 0;
883 }
884 mtx_unlock(mtxp);
885 }
886
887 static off_t
foffset_read(struct file * fp)888 foffset_read(struct file *fp)
889 {
890
891 return (foffset_lock(fp, FOF_NOLOCK));
892 }
893 #endif
894
895 void
foffset_lock_uio(struct file * fp,struct uio * uio,int flags)896 foffset_lock_uio(struct file *fp, struct uio *uio, int flags)
897 {
898
899 if ((flags & FOF_OFFSET) == 0)
900 uio->uio_offset = foffset_lock(fp, flags);
901 }
902
903 void
foffset_unlock_uio(struct file * fp,struct uio * uio,int flags)904 foffset_unlock_uio(struct file *fp, struct uio *uio, int flags)
905 {
906
907 if ((flags & FOF_OFFSET) == 0)
908 foffset_unlock(fp, uio->uio_offset, flags);
909 }
910
911 static int
get_advice(struct file * fp,struct uio * uio)912 get_advice(struct file *fp, struct uio *uio)
913 {
914 struct mtx *mtxp;
915 int ret;
916
917 ret = POSIX_FADV_NORMAL;
918 if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG)
919 return (ret);
920
921 mtxp = mtx_pool_find(mtxpool_sleep, fp);
922 mtx_lock(mtxp);
923 if (fp->f_advice != NULL &&
924 uio->uio_offset >= fp->f_advice->fa_start &&
925 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end)
926 ret = fp->f_advice->fa_advice;
927 mtx_unlock(mtxp);
928 return (ret);
929 }
930
931 static int
get_write_ioflag(struct file * fp)932 get_write_ioflag(struct file *fp)
933 {
934 int ioflag;
935 struct mount *mp;
936 struct vnode *vp;
937
938 ioflag = 0;
939 vp = fp->f_vnode;
940 mp = atomic_load_ptr(&vp->v_mount);
941
942 if ((fp->f_flag & O_DIRECT) != 0)
943 ioflag |= IO_DIRECT;
944
945 if ((fp->f_flag & O_FSYNC) != 0 ||
946 (mp != NULL && (mp->mnt_flag & MNT_SYNCHRONOUS) != 0))
947 ioflag |= IO_SYNC;
948
949 /*
950 * For O_DSYNC we set both IO_SYNC and IO_DATASYNC, so that VOP_WRITE()
951 * or VOP_DEALLOCATE() implementations that don't understand IO_DATASYNC
952 * fall back to full O_SYNC behavior.
953 */
954 if ((fp->f_flag & O_DSYNC) != 0)
955 ioflag |= IO_SYNC | IO_DATASYNC;
956
957 return (ioflag);
958 }
959
960 int
vn_read_from_obj(struct vnode * vp,struct uio * uio)961 vn_read_from_obj(struct vnode *vp, struct uio *uio)
962 {
963 vm_object_t obj;
964 vm_page_t ma[io_hold_cnt + 2];
965 off_t off, vsz;
966 ssize_t resid;
967 int error, i, j;
968
969 MPASS(uio->uio_resid <= ptoa(io_hold_cnt + 2));
970 obj = atomic_load_ptr(&vp->v_object);
971 if (obj == NULL)
972 return (EJUSTRETURN);
973
974 /*
975 * Depends on type stability of vm_objects.
976 */
977 vm_object_pip_add(obj, 1);
978 if ((obj->flags & OBJ_DEAD) != 0) {
979 /*
980 * Note that object might be already reused from the
981 * vnode, and the OBJ_DEAD flag cleared. This is fine,
982 * we recheck for DOOMED vnode state after all pages
983 * are busied, and retract then.
984 *
985 * But we check for OBJ_DEAD to ensure that we do not
986 * busy pages while vm_object_terminate_pages()
987 * processes the queue.
988 */
989 error = EJUSTRETURN;
990 goto out_pip;
991 }
992
993 resid = uio->uio_resid;
994 off = uio->uio_offset;
995 for (i = 0; resid > 0; i++) {
996 MPASS(i < io_hold_cnt + 2);
997 ma[i] = vm_page_grab_unlocked(obj, atop(off),
998 VM_ALLOC_NOCREAT | VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY |
999 VM_ALLOC_NOWAIT);
1000 if (ma[i] == NULL)
1001 break;
1002
1003 /*
1004 * Skip invalid pages. Valid mask can be partial only
1005 * at EOF, and we clip later.
1006 */
1007 if (vm_page_none_valid(ma[i])) {
1008 vm_page_sunbusy(ma[i]);
1009 break;
1010 }
1011
1012 resid -= PAGE_SIZE;
1013 off += PAGE_SIZE;
1014 }
1015 if (i == 0) {
1016 error = EJUSTRETURN;
1017 goto out_pip;
1018 }
1019
1020 /*
1021 * Check VIRF_DOOMED after we busied our pages. Since
1022 * vgonel() terminates the vnode' vm_object, it cannot
1023 * process past pages busied by us.
1024 */
1025 if (VN_IS_DOOMED(vp)) {
1026 error = EJUSTRETURN;
1027 goto out;
1028 }
1029
1030 resid = PAGE_SIZE - (uio->uio_offset & PAGE_MASK) + ptoa(i - 1);
1031 if (resid > uio->uio_resid)
1032 resid = uio->uio_resid;
1033
1034 /*
1035 * Unlocked read of vnp_size is safe because truncation cannot
1036 * pass busied page. But we load vnp_size into a local
1037 * variable so that possible concurrent extension does not
1038 * break calculation.
1039 */
1040 #if defined(__powerpc__) && !defined(__powerpc64__)
1041 vsz = obj->un_pager.vnp.vnp_size;
1042 #else
1043 vsz = atomic_load_64(&obj->un_pager.vnp.vnp_size);
1044 #endif
1045 if (uio->uio_offset >= vsz) {
1046 error = EJUSTRETURN;
1047 goto out;
1048 }
1049 if (uio->uio_offset + resid > vsz)
1050 resid = vsz - uio->uio_offset;
1051
1052 error = vn_io_fault_pgmove(ma, uio->uio_offset & PAGE_MASK, resid, uio);
1053
1054 out:
1055 for (j = 0; j < i; j++) {
1056 if (error == 0)
1057 vm_page_reference(ma[j]);
1058 vm_page_sunbusy(ma[j]);
1059 }
1060 out_pip:
1061 vm_object_pip_wakeup(obj);
1062 if (error != 0)
1063 return (error);
1064 return (uio->uio_resid == 0 ? 0 : EJUSTRETURN);
1065 }
1066
1067 /*
1068 * File table vnode read routine.
1069 */
1070 static int
vn_read(struct file * fp,struct uio * uio,struct ucred * active_cred,int flags,struct thread * td)1071 vn_read(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags,
1072 struct thread *td)
1073 {
1074 struct vnode *vp;
1075 off_t orig_offset;
1076 int error, ioflag;
1077 int advice;
1078
1079 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
1080 uio->uio_td, td));
1081 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET"));
1082 vp = fp->f_vnode;
1083 ioflag = 0;
1084 if (fp->f_flag & FNONBLOCK)
1085 ioflag |= IO_NDELAY;
1086 if (fp->f_flag & O_DIRECT)
1087 ioflag |= IO_DIRECT;
1088
1089 /*
1090 * Try to read from page cache. VIRF_DOOMED check is racy but
1091 * allows us to avoid unneeded work outright.
1092 */
1093 if (vn_io_pgcache_read_enable && !mac_vnode_check_read_enabled() &&
1094 (vn_irflag_read(vp) & (VIRF_DOOMED | VIRF_PGREAD)) == VIRF_PGREAD) {
1095 error = VOP_READ_PGCACHE(vp, uio, ioflag, fp->f_cred);
1096 if (error == 0) {
1097 fp->f_nextoff[UIO_READ] = uio->uio_offset;
1098 return (0);
1099 }
1100 if (error != EJUSTRETURN)
1101 return (error);
1102 }
1103
1104 advice = get_advice(fp, uio);
1105 vn_lock(vp, LK_SHARED | LK_RETRY);
1106
1107 switch (advice) {
1108 case POSIX_FADV_NORMAL:
1109 case POSIX_FADV_SEQUENTIAL:
1110 case POSIX_FADV_NOREUSE:
1111 ioflag |= sequential_heuristic(uio, fp);
1112 break;
1113 case POSIX_FADV_RANDOM:
1114 /* Disable read-ahead for random I/O. */
1115 break;
1116 }
1117 orig_offset = uio->uio_offset;
1118
1119 #ifdef MAC
1120 error = mac_vnode_check_read(active_cred, fp->f_cred, vp);
1121 if (error == 0)
1122 #endif
1123 error = VOP_READ(vp, uio, ioflag, fp->f_cred);
1124 fp->f_nextoff[UIO_READ] = uio->uio_offset;
1125 VOP_UNLOCK(vp);
1126 if (error == 0 && advice == POSIX_FADV_NOREUSE &&
1127 orig_offset != uio->uio_offset)
1128 /*
1129 * Use POSIX_FADV_DONTNEED to flush pages and buffers
1130 * for the backing file after a POSIX_FADV_NOREUSE
1131 * read(2).
1132 */
1133 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1,
1134 POSIX_FADV_DONTNEED);
1135 return (error);
1136 }
1137
1138 /*
1139 * File table vnode write routine.
1140 */
1141 static int
vn_write(struct file * fp,struct uio * uio,struct ucred * active_cred,int flags,struct thread * td)1142 vn_write(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags,
1143 struct thread *td)
1144 {
1145 struct vnode *vp;
1146 struct mount *mp;
1147 off_t orig_offset;
1148 int error, ioflag;
1149 int advice;
1150 bool need_finished_write;
1151
1152 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
1153 uio->uio_td, td));
1154 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET"));
1155 vp = fp->f_vnode;
1156 if (vp->v_type == VREG)
1157 bwillwrite();
1158 ioflag = IO_UNIT;
1159 if (vp->v_type == VREG && (fp->f_flag & O_APPEND) != 0)
1160 ioflag |= IO_APPEND;
1161 if ((fp->f_flag & FNONBLOCK) != 0)
1162 ioflag |= IO_NDELAY;
1163 ioflag |= get_write_ioflag(fp);
1164
1165 mp = NULL;
1166 need_finished_write = false;
1167 if (vp->v_type != VCHR) {
1168 error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH);
1169 if (error != 0)
1170 goto unlock;
1171 need_finished_write = true;
1172 }
1173
1174 advice = get_advice(fp, uio);
1175
1176 vn_lock(vp, vn_lktype_write(mp, vp) | LK_RETRY);
1177 switch (advice) {
1178 case POSIX_FADV_NORMAL:
1179 case POSIX_FADV_SEQUENTIAL:
1180 case POSIX_FADV_NOREUSE:
1181 ioflag |= sequential_heuristic(uio, fp);
1182 break;
1183 case POSIX_FADV_RANDOM:
1184 /* XXX: Is this correct? */
1185 break;
1186 }
1187 orig_offset = uio->uio_offset;
1188
1189 #ifdef MAC
1190 error = mac_vnode_check_write(active_cred, fp->f_cred, vp);
1191 if (error == 0)
1192 #endif
1193 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred);
1194 fp->f_nextoff[UIO_WRITE] = uio->uio_offset;
1195 VOP_UNLOCK(vp);
1196 if (need_finished_write)
1197 vn_finished_write(mp);
1198 if (error == 0 && advice == POSIX_FADV_NOREUSE &&
1199 orig_offset != uio->uio_offset)
1200 /*
1201 * Use POSIX_FADV_DONTNEED to flush pages and buffers
1202 * for the backing file after a POSIX_FADV_NOREUSE
1203 * write(2).
1204 */
1205 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1,
1206 POSIX_FADV_DONTNEED);
1207 unlock:
1208 return (error);
1209 }
1210
1211 /*
1212 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to
1213 * prevent the following deadlock:
1214 *
1215 * Assume that the thread A reads from the vnode vp1 into userspace
1216 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is
1217 * currently not resident, then system ends up with the call chain
1218 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] ->
1219 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2)
1220 * which establishes lock order vp1->vn_lock, then vp2->vn_lock.
1221 * If, at the same time, thread B reads from vnode vp2 into buffer buf2
1222 * backed by the pages of vnode vp1, and some page in buf2 is not
1223 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock.
1224 *
1225 * To prevent the lock order reversal and deadlock, vn_io_fault() does
1226 * not allow page faults to happen during VOP_READ() or VOP_WRITE().
1227 * Instead, it first tries to do the whole range i/o with pagefaults
1228 * disabled. If all pages in the i/o buffer are resident and mapped,
1229 * VOP will succeed (ignoring the genuine filesystem errors).
1230 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do
1231 * i/o in chunks, with all pages in the chunk prefaulted and held
1232 * using vm_fault_quick_hold_pages().
1233 *
1234 * Filesystems using this deadlock avoidance scheme should use the
1235 * array of the held pages from uio, saved in the curthread->td_ma,
1236 * instead of doing uiomove(). A helper function
1237 * vn_io_fault_uiomove() converts uiomove request into
1238 * uiomove_fromphys() over td_ma array.
1239 *
1240 * Since vnode locks do not cover the whole i/o anymore, rangelocks
1241 * make the current i/o request atomic with respect to other i/os and
1242 * truncations.
1243 */
1244
1245 /*
1246 * Decode vn_io_fault_args and perform the corresponding i/o.
1247 */
1248 static int
vn_io_fault_doio(struct vn_io_fault_args * args,struct uio * uio,struct thread * td)1249 vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio,
1250 struct thread *td)
1251 {
1252 int error, save;
1253
1254 error = 0;
1255 save = vm_fault_disable_pagefaults();
1256 switch (args->kind) {
1257 case VN_IO_FAULT_FOP:
1258 error = (args->args.fop_args.doio)(args->args.fop_args.fp,
1259 uio, args->cred, args->flags, td);
1260 break;
1261 case VN_IO_FAULT_VOP:
1262 if (uio->uio_rw == UIO_READ) {
1263 error = VOP_READ(args->args.vop_args.vp, uio,
1264 args->flags, args->cred);
1265 } else if (uio->uio_rw == UIO_WRITE) {
1266 error = VOP_WRITE(args->args.vop_args.vp, uio,
1267 args->flags, args->cred);
1268 }
1269 break;
1270 default:
1271 panic("vn_io_fault_doio: unknown kind of io %d %d",
1272 args->kind, uio->uio_rw);
1273 }
1274 vm_fault_enable_pagefaults(save);
1275 return (error);
1276 }
1277
1278 static int
vn_io_fault_touch(char * base,const struct uio * uio)1279 vn_io_fault_touch(char *base, const struct uio *uio)
1280 {
1281 int r;
1282
1283 r = fubyte(base);
1284 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1))
1285 return (EFAULT);
1286 return (0);
1287 }
1288
1289 static int
vn_io_fault_prefault_user(const struct uio * uio)1290 vn_io_fault_prefault_user(const struct uio *uio)
1291 {
1292 char *base;
1293 const struct iovec *iov;
1294 size_t len;
1295 ssize_t resid;
1296 int error, i;
1297
1298 KASSERT(uio->uio_segflg == UIO_USERSPACE,
1299 ("vn_io_fault_prefault userspace"));
1300
1301 error = i = 0;
1302 iov = uio->uio_iov;
1303 resid = uio->uio_resid;
1304 base = iov->iov_base;
1305 len = iov->iov_len;
1306 while (resid > 0) {
1307 error = vn_io_fault_touch(base, uio);
1308 if (error != 0)
1309 break;
1310 if (len < PAGE_SIZE) {
1311 if (len != 0) {
1312 error = vn_io_fault_touch(base + len - 1, uio);
1313 if (error != 0)
1314 break;
1315 resid -= len;
1316 }
1317 if (++i >= uio->uio_iovcnt)
1318 break;
1319 iov = uio->uio_iov + i;
1320 base = iov->iov_base;
1321 len = iov->iov_len;
1322 } else {
1323 len -= PAGE_SIZE;
1324 base += PAGE_SIZE;
1325 resid -= PAGE_SIZE;
1326 }
1327 }
1328 return (error);
1329 }
1330
1331 /*
1332 * Common code for vn_io_fault(), agnostic to the kind of i/o request.
1333 * Uses vn_io_fault_doio() to make the call to an actual i/o function.
1334 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request
1335 * into args and call vn_io_fault1() to handle faults during the user
1336 * mode buffer accesses.
1337 */
1338 static int
vn_io_fault1(struct vnode * vp,struct uio * uio,struct vn_io_fault_args * args,struct thread * td)1339 vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args,
1340 struct thread *td)
1341 {
1342 vm_page_t ma[io_hold_cnt + 2];
1343 struct uio *uio_clone, short_uio;
1344 struct iovec short_iovec[1];
1345 vm_page_t *prev_td_ma;
1346 vm_prot_t prot;
1347 vm_offset_t addr, end;
1348 size_t len, resid;
1349 ssize_t adv;
1350 int error, cnt, saveheld, prev_td_ma_cnt;
1351
1352 if (vn_io_fault_prefault) {
1353 error = vn_io_fault_prefault_user(uio);
1354 if (error != 0)
1355 return (error); /* Or ignore ? */
1356 }
1357
1358 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ;
1359
1360 /*
1361 * The UFS follows IO_UNIT directive and replays back both
1362 * uio_offset and uio_resid if an error is encountered during the
1363 * operation. But, since the iovec may be already advanced,
1364 * uio is still in an inconsistent state.
1365 *
1366 * Cache a copy of the original uio, which is advanced to the redo
1367 * point using UIO_NOCOPY below.
1368 */
1369 uio_clone = cloneuio(uio);
1370 resid = uio->uio_resid;
1371
1372 short_uio.uio_segflg = UIO_USERSPACE;
1373 short_uio.uio_rw = uio->uio_rw;
1374 short_uio.uio_td = uio->uio_td;
1375
1376 error = vn_io_fault_doio(args, uio, td);
1377 if (error != EFAULT)
1378 goto out;
1379
1380 atomic_add_long(&vn_io_faults_cnt, 1);
1381 uio_clone->uio_segflg = UIO_NOCOPY;
1382 uiomove(NULL, resid - uio->uio_resid, uio_clone);
1383 uio_clone->uio_segflg = uio->uio_segflg;
1384
1385 saveheld = curthread_pflags_set(TDP_UIOHELD);
1386 prev_td_ma = td->td_ma;
1387 prev_td_ma_cnt = td->td_ma_cnt;
1388
1389 while (uio_clone->uio_resid != 0) {
1390 len = uio_clone->uio_iov->iov_len;
1391 if (len == 0) {
1392 KASSERT(uio_clone->uio_iovcnt >= 1,
1393 ("iovcnt underflow"));
1394 uio_clone->uio_iov++;
1395 uio_clone->uio_iovcnt--;
1396 continue;
1397 }
1398 if (len > ptoa(io_hold_cnt))
1399 len = ptoa(io_hold_cnt);
1400 addr = (uintptr_t)uio_clone->uio_iov->iov_base;
1401 end = round_page(addr + len);
1402 if (end < addr) {
1403 error = EFAULT;
1404 break;
1405 }
1406 /*
1407 * A perfectly misaligned address and length could cause
1408 * both the start and the end of the chunk to use partial
1409 * page. +2 accounts for such a situation.
1410 */
1411 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map,
1412 addr, len, prot, ma, io_hold_cnt + 2);
1413 if (cnt == -1) {
1414 error = EFAULT;
1415 break;
1416 }
1417 short_uio.uio_iov = &short_iovec[0];
1418 short_iovec[0].iov_base = (void *)addr;
1419 short_uio.uio_iovcnt = 1;
1420 short_uio.uio_resid = short_iovec[0].iov_len = len;
1421 short_uio.uio_offset = uio_clone->uio_offset;
1422 td->td_ma = ma;
1423 td->td_ma_cnt = cnt;
1424
1425 error = vn_io_fault_doio(args, &short_uio, td);
1426 vm_page_unhold_pages(ma, cnt);
1427 adv = len - short_uio.uio_resid;
1428
1429 uio_clone->uio_iov->iov_base =
1430 (char *)uio_clone->uio_iov->iov_base + adv;
1431 uio_clone->uio_iov->iov_len -= adv;
1432 uio_clone->uio_resid -= adv;
1433 uio_clone->uio_offset += adv;
1434
1435 uio->uio_resid -= adv;
1436 uio->uio_offset += adv;
1437
1438 if (error != 0 || adv == 0)
1439 break;
1440 }
1441 td->td_ma = prev_td_ma;
1442 td->td_ma_cnt = prev_td_ma_cnt;
1443 curthread_pflags_restore(saveheld);
1444 out:
1445 freeuio(uio_clone);
1446 return (error);
1447 }
1448
1449 static int
vn_io_fault(struct file * fp,struct uio * uio,struct ucred * active_cred,int flags,struct thread * td)1450 vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred,
1451 int flags, struct thread *td)
1452 {
1453 fo_rdwr_t *doio;
1454 struct vnode *vp;
1455 void *rl_cookie;
1456 struct vn_io_fault_args args;
1457 int error;
1458 bool do_io_fault, do_rangelock;
1459
1460 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write;
1461 vp = fp->f_vnode;
1462
1463 /*
1464 * The ability to read(2) on a directory has historically been
1465 * allowed for all users, but this can and has been the source of
1466 * at least one security issue in the past. As such, it is now hidden
1467 * away behind a sysctl for those that actually need it to use it, and
1468 * restricted to root when it's turned on to make it relatively safe to
1469 * leave on for longer sessions of need.
1470 */
1471 if (vp->v_type == VDIR) {
1472 KASSERT(uio->uio_rw == UIO_READ,
1473 ("illegal write attempted on a directory"));
1474 if (!vfs_allow_read_dir)
1475 return (EISDIR);
1476 if ((error = priv_check(td, PRIV_VFS_READ_DIR)) != 0)
1477 return (EISDIR);
1478 }
1479
1480 do_io_fault = do_vn_io_fault(vp, uio);
1481 do_rangelock = do_io_fault || (vn_irflag_read(vp) & VIRF_PGREAD) != 0;
1482 foffset_lock_uio(fp, uio, flags);
1483 if (do_rangelock) {
1484 if (uio->uio_rw == UIO_READ) {
1485 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset,
1486 uio->uio_offset + uio->uio_resid);
1487 } else if ((fp->f_flag & O_APPEND) != 0 ||
1488 (flags & FOF_OFFSET) == 0) {
1489 /* For appenders, punt and lock the whole range. */
1490 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
1491 } else {
1492 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset,
1493 uio->uio_offset + uio->uio_resid);
1494 }
1495 }
1496 if (do_io_fault) {
1497 args.kind = VN_IO_FAULT_FOP;
1498 args.args.fop_args.fp = fp;
1499 args.args.fop_args.doio = doio;
1500 args.cred = active_cred;
1501 args.flags = flags | FOF_OFFSET;
1502 error = vn_io_fault1(vp, uio, &args, td);
1503 } else {
1504 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td);
1505 }
1506 if (do_rangelock)
1507 vn_rangelock_unlock(vp, rl_cookie);
1508 foffset_unlock_uio(fp, uio, flags);
1509 return (error);
1510 }
1511
1512 /*
1513 * Helper function to perform the requested uiomove operation using
1514 * the held pages for io->uio_iov[0].iov_base buffer instead of
1515 * copyin/copyout. Access to the pages with uiomove_fromphys()
1516 * instead of iov_base prevents page faults that could occur due to
1517 * pmap_collect() invalidating the mapping created by
1518 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or
1519 * object cleanup revoking the write access from page mappings.
1520 *
1521 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove()
1522 * instead of plain uiomove().
1523 */
1524 int
vn_io_fault_uiomove(char * data,int xfersize,struct uio * uio)1525 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio)
1526 {
1527 struct uio transp_uio;
1528 struct iovec transp_iov[1];
1529 struct thread *td;
1530 size_t adv;
1531 int error, pgadv;
1532
1533 td = curthread;
1534 if ((td->td_pflags & TDP_UIOHELD) == 0 ||
1535 uio->uio_segflg != UIO_USERSPACE)
1536 return (uiomove(data, xfersize, uio));
1537
1538 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt));
1539 transp_iov[0].iov_base = data;
1540 transp_uio.uio_iov = &transp_iov[0];
1541 transp_uio.uio_iovcnt = 1;
1542 if (xfersize > uio->uio_resid)
1543 xfersize = uio->uio_resid;
1544 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize;
1545 transp_uio.uio_offset = 0;
1546 transp_uio.uio_segflg = UIO_SYSSPACE;
1547 /*
1548 * Since transp_iov points to data, and td_ma page array
1549 * corresponds to original uio->uio_iov, we need to invert the
1550 * direction of the i/o operation as passed to
1551 * uiomove_fromphys().
1552 */
1553 switch (uio->uio_rw) {
1554 case UIO_WRITE:
1555 transp_uio.uio_rw = UIO_READ;
1556 break;
1557 case UIO_READ:
1558 transp_uio.uio_rw = UIO_WRITE;
1559 break;
1560 }
1561 transp_uio.uio_td = uio->uio_td;
1562 error = uiomove_fromphys(td->td_ma,
1563 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK,
1564 xfersize, &transp_uio);
1565 adv = xfersize - transp_uio.uio_resid;
1566 pgadv =
1567 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) -
1568 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT);
1569 td->td_ma += pgadv;
1570 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt,
1571 pgadv));
1572 td->td_ma_cnt -= pgadv;
1573 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv;
1574 uio->uio_iov->iov_len -= adv;
1575 uio->uio_resid -= adv;
1576 uio->uio_offset += adv;
1577 return (error);
1578 }
1579
1580 int
vn_io_fault_pgmove(vm_page_t ma[],vm_offset_t offset,int xfersize,struct uio * uio)1581 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize,
1582 struct uio *uio)
1583 {
1584 struct thread *td;
1585 vm_offset_t iov_base;
1586 int cnt, pgadv;
1587
1588 td = curthread;
1589 if ((td->td_pflags & TDP_UIOHELD) == 0 ||
1590 uio->uio_segflg != UIO_USERSPACE)
1591 return (uiomove_fromphys(ma, offset, xfersize, uio));
1592
1593 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt));
1594 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize;
1595 iov_base = (vm_offset_t)uio->uio_iov->iov_base;
1596 switch (uio->uio_rw) {
1597 case UIO_WRITE:
1598 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma,
1599 offset, cnt);
1600 break;
1601 case UIO_READ:
1602 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK,
1603 cnt);
1604 break;
1605 }
1606 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT);
1607 td->td_ma += pgadv;
1608 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt,
1609 pgadv));
1610 td->td_ma_cnt -= pgadv;
1611 uio->uio_iov->iov_base = (char *)(iov_base + cnt);
1612 uio->uio_iov->iov_len -= cnt;
1613 uio->uio_resid -= cnt;
1614 uio->uio_offset += cnt;
1615 return (0);
1616 }
1617
1618 /*
1619 * File table truncate routine.
1620 */
1621 static int
vn_truncate(struct file * fp,off_t length,struct ucred * active_cred,struct thread * td)1622 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred,
1623 struct thread *td)
1624 {
1625 struct mount *mp;
1626 struct vnode *vp;
1627 void *rl_cookie;
1628 int error;
1629
1630 vp = fp->f_vnode;
1631
1632 retry:
1633 /*
1634 * Lock the whole range for truncation. Otherwise split i/o
1635 * might happen partly before and partly after the truncation.
1636 */
1637 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
1638 error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH);
1639 if (error)
1640 goto out1;
1641 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1642 AUDIT_ARG_VNODE1(vp);
1643 if (vp->v_type == VDIR) {
1644 error = EISDIR;
1645 goto out;
1646 }
1647 #ifdef MAC
1648 error = mac_vnode_check_write(active_cred, fp->f_cred, vp);
1649 if (error)
1650 goto out;
1651 #endif
1652 error = vn_truncate_locked(vp, length, (fp->f_flag & O_FSYNC) != 0,
1653 fp->f_cred);
1654 out:
1655 VOP_UNLOCK(vp);
1656 vn_finished_write(mp);
1657 out1:
1658 vn_rangelock_unlock(vp, rl_cookie);
1659 if (error == ERELOOKUP)
1660 goto retry;
1661 return (error);
1662 }
1663
1664 /*
1665 * Truncate a file that is already locked.
1666 */
1667 int
vn_truncate_locked(struct vnode * vp,off_t length,bool sync,struct ucred * cred)1668 vn_truncate_locked(struct vnode *vp, off_t length, bool sync,
1669 struct ucred *cred)
1670 {
1671 struct vattr vattr;
1672 int error;
1673
1674 error = VOP_ADD_WRITECOUNT(vp, 1);
1675 if (error == 0) {
1676 VATTR_NULL(&vattr);
1677 vattr.va_size = length;
1678 if (sync)
1679 vattr.va_vaflags |= VA_SYNC;
1680 error = VOP_SETATTR(vp, &vattr, cred);
1681 VOP_ADD_WRITECOUNT_CHECKED(vp, -1);
1682 }
1683 return (error);
1684 }
1685
1686 /*
1687 * File table vnode stat routine.
1688 */
1689 int
vn_statfile(struct file * fp,struct stat * sb,struct ucred * active_cred)1690 vn_statfile(struct file *fp, struct stat *sb, struct ucred *active_cred)
1691 {
1692 struct vnode *vp = fp->f_vnode;
1693 int error;
1694
1695 vn_lock(vp, LK_SHARED | LK_RETRY);
1696 error = VOP_STAT(vp, sb, active_cred, fp->f_cred);
1697 VOP_UNLOCK(vp);
1698
1699 return (error);
1700 }
1701
1702 /*
1703 * File table vnode ioctl routine.
1704 */
1705 static int
vn_ioctl(struct file * fp,u_long com,void * data,struct ucred * active_cred,struct thread * td)1706 vn_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred,
1707 struct thread *td)
1708 {
1709 struct vnode *vp;
1710 struct fiobmap2_arg *bmarg;
1711 off_t size;
1712 int error;
1713
1714 vp = fp->f_vnode;
1715 switch (vp->v_type) {
1716 case VDIR:
1717 case VREG:
1718 switch (com) {
1719 case FIONREAD:
1720 error = vn_getsize(vp, &size, active_cred);
1721 if (error == 0)
1722 *(int *)data = size - fp->f_offset;
1723 return (error);
1724 case FIOBMAP2:
1725 bmarg = (struct fiobmap2_arg *)data;
1726 vn_lock(vp, LK_SHARED | LK_RETRY);
1727 #ifdef MAC
1728 error = mac_vnode_check_read(active_cred, fp->f_cred,
1729 vp);
1730 if (error == 0)
1731 #endif
1732 error = VOP_BMAP(vp, bmarg->bn, NULL,
1733 &bmarg->bn, &bmarg->runp, &bmarg->runb);
1734 VOP_UNLOCK(vp);
1735 return (error);
1736 case FIONBIO:
1737 case FIOASYNC:
1738 return (0);
1739 default:
1740 return (VOP_IOCTL(vp, com, data, fp->f_flag,
1741 active_cred, td));
1742 }
1743 break;
1744 case VCHR:
1745 return (VOP_IOCTL(vp, com, data, fp->f_flag,
1746 active_cred, td));
1747 default:
1748 return (ENOTTY);
1749 }
1750 }
1751
1752 /*
1753 * File table vnode poll routine.
1754 */
1755 static int
vn_poll(struct file * fp,int events,struct ucred * active_cred,struct thread * td)1756 vn_poll(struct file *fp, int events, struct ucred *active_cred,
1757 struct thread *td)
1758 {
1759 struct vnode *vp;
1760 int error;
1761
1762 vp = fp->f_vnode;
1763 #if defined(MAC) || defined(AUDIT)
1764 if (AUDITING_TD(td) || mac_vnode_check_poll_enabled()) {
1765 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1766 AUDIT_ARG_VNODE1(vp);
1767 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp);
1768 VOP_UNLOCK(vp);
1769 if (error != 0)
1770 return (error);
1771 }
1772 #endif
1773 error = VOP_POLL(vp, events, fp->f_cred, td);
1774 return (error);
1775 }
1776
1777 /*
1778 * Acquire the requested lock and then check for validity. LK_RETRY
1779 * permits vn_lock to return doomed vnodes.
1780 */
1781 static int __noinline
_vn_lock_fallback(struct vnode * vp,int flags,const char * file,int line,int error)1782 _vn_lock_fallback(struct vnode *vp, int flags, const char *file, int line,
1783 int error)
1784 {
1785
1786 KASSERT((flags & LK_RETRY) == 0 || error == 0,
1787 ("vn_lock: error %d incompatible with flags %#x", error, flags));
1788
1789 if (error == 0)
1790 VNASSERT(VN_IS_DOOMED(vp), vp, ("vnode not doomed"));
1791
1792 if ((flags & LK_RETRY) == 0) {
1793 if (error == 0) {
1794 VOP_UNLOCK(vp);
1795 error = ENOENT;
1796 }
1797 return (error);
1798 }
1799
1800 /*
1801 * LK_RETRY case.
1802 *
1803 * Nothing to do if we got the lock.
1804 */
1805 if (error == 0)
1806 return (0);
1807
1808 /*
1809 * Interlock was dropped by the call in _vn_lock.
1810 */
1811 flags &= ~LK_INTERLOCK;
1812 do {
1813 error = VOP_LOCK1(vp, flags, file, line);
1814 } while (error != 0);
1815 return (0);
1816 }
1817
1818 int
_vn_lock(struct vnode * vp,int flags,const char * file,int line)1819 _vn_lock(struct vnode *vp, int flags, const char *file, int line)
1820 {
1821 int error;
1822
1823 VNASSERT((flags & LK_TYPE_MASK) != 0, vp,
1824 ("vn_lock: no locktype (%d passed)", flags));
1825 VNPASS(vp->v_holdcnt > 0, vp);
1826 error = VOP_LOCK1(vp, flags, file, line);
1827 if (__predict_false(error != 0 || VN_IS_DOOMED(vp)))
1828 return (_vn_lock_fallback(vp, flags, file, line, error));
1829 return (0);
1830 }
1831
1832 /*
1833 * File table vnode close routine.
1834 */
1835 static int
vn_closefile(struct file * fp,struct thread * td)1836 vn_closefile(struct file *fp, struct thread *td)
1837 {
1838 struct vnode *vp;
1839 struct flock lf;
1840 int error;
1841 bool ref;
1842
1843 vp = fp->f_vnode;
1844 fp->f_ops = &badfileops;
1845 ref = (fp->f_flag & FHASLOCK) != 0;
1846
1847 error = vn_close1(vp, fp->f_flag, fp->f_cred, td, ref);
1848
1849 if (__predict_false(ref)) {
1850 lf.l_whence = SEEK_SET;
1851 lf.l_start = 0;
1852 lf.l_len = 0;
1853 lf.l_type = F_UNLCK;
1854 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK);
1855 vrele(vp);
1856 }
1857 return (error);
1858 }
1859
1860 /*
1861 * Preparing to start a filesystem write operation. If the operation is
1862 * permitted, then we bump the count of operations in progress and
1863 * proceed. If a suspend request is in progress, we wait until the
1864 * suspension is over, and then proceed.
1865 */
1866 static int
vn_start_write_refed(struct mount * mp,int flags,bool mplocked)1867 vn_start_write_refed(struct mount *mp, int flags, bool mplocked)
1868 {
1869 struct mount_pcpu *mpcpu;
1870 int error, mflags;
1871
1872 if (__predict_true(!mplocked) && (flags & V_XSLEEP) == 0 &&
1873 vfs_op_thread_enter(mp, mpcpu)) {
1874 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0);
1875 vfs_mp_count_add_pcpu(mpcpu, writeopcount, 1);
1876 vfs_op_thread_exit(mp, mpcpu);
1877 return (0);
1878 }
1879
1880 if (mplocked)
1881 mtx_assert(MNT_MTX(mp), MA_OWNED);
1882 else
1883 MNT_ILOCK(mp);
1884
1885 error = 0;
1886
1887 /*
1888 * Check on status of suspension.
1889 */
1890 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 ||
1891 mp->mnt_susp_owner != curthread) {
1892 mflags = 0;
1893 if ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0) {
1894 if (flags & V_PCATCH)
1895 mflags |= PCATCH;
1896 }
1897 mflags |= (PUSER - 1);
1898 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
1899 if ((flags & V_NOWAIT) != 0) {
1900 error = EWOULDBLOCK;
1901 goto unlock;
1902 }
1903 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags,
1904 "suspfs", 0);
1905 if (error != 0)
1906 goto unlock;
1907 }
1908 }
1909 if ((flags & V_XSLEEP) != 0)
1910 goto unlock;
1911 mp->mnt_writeopcount++;
1912 unlock:
1913 if (error != 0 || (flags & V_XSLEEP) != 0)
1914 MNT_REL(mp);
1915 MNT_IUNLOCK(mp);
1916 return (error);
1917 }
1918
1919 int
vn_start_write(struct vnode * vp,struct mount ** mpp,int flags)1920 vn_start_write(struct vnode *vp, struct mount **mpp, int flags)
1921 {
1922 struct mount *mp;
1923 int error;
1924
1925 KASSERT((flags & ~V_VALID_FLAGS) == 0,
1926 ("%s: invalid flags passed %d\n", __func__, flags));
1927
1928 error = 0;
1929 /*
1930 * If a vnode is provided, get and return the mount point that
1931 * to which it will write.
1932 */
1933 if (vp != NULL) {
1934 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
1935 *mpp = NULL;
1936 if (error != EOPNOTSUPP)
1937 return (error);
1938 return (0);
1939 }
1940 }
1941 if ((mp = *mpp) == NULL)
1942 return (0);
1943
1944 /*
1945 * VOP_GETWRITEMOUNT() returns with the mp refcount held through
1946 * a vfs_ref().
1947 * As long as a vnode is not provided we need to acquire a
1948 * refcount for the provided mountpoint too, in order to
1949 * emulate a vfs_ref().
1950 */
1951 if (vp == NULL)
1952 vfs_ref(mp);
1953
1954 error = vn_start_write_refed(mp, flags, false);
1955 if (error != 0 && (flags & V_NOWAIT) == 0)
1956 *mpp = NULL;
1957 return (error);
1958 }
1959
1960 /*
1961 * Secondary suspension. Used by operations such as vop_inactive
1962 * routines that are needed by the higher level functions. These
1963 * are allowed to proceed until all the higher level functions have
1964 * completed (indicated by mnt_writeopcount dropping to zero). At that
1965 * time, these operations are halted until the suspension is over.
1966 */
1967 int
vn_start_secondary_write(struct vnode * vp,struct mount ** mpp,int flags)1968 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags)
1969 {
1970 struct mount *mp;
1971 int error, mflags;
1972
1973 KASSERT((flags & (~V_VALID_FLAGS | V_XSLEEP)) == 0,
1974 ("%s: invalid flags passed %d\n", __func__, flags));
1975
1976 retry:
1977 if (vp != NULL) {
1978 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
1979 *mpp = NULL;
1980 if (error != EOPNOTSUPP)
1981 return (error);
1982 return (0);
1983 }
1984 }
1985 /*
1986 * If we are not suspended or have not yet reached suspended
1987 * mode, then let the operation proceed.
1988 */
1989 if ((mp = *mpp) == NULL)
1990 return (0);
1991
1992 /*
1993 * VOP_GETWRITEMOUNT() returns with the mp refcount held through
1994 * a vfs_ref().
1995 * As long as a vnode is not provided we need to acquire a
1996 * refcount for the provided mountpoint too, in order to
1997 * emulate a vfs_ref().
1998 */
1999 MNT_ILOCK(mp);
2000 if (vp == NULL)
2001 MNT_REF(mp);
2002 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) {
2003 mp->mnt_secondary_writes++;
2004 mp->mnt_secondary_accwrites++;
2005 MNT_IUNLOCK(mp);
2006 return (0);
2007 }
2008 if ((flags & V_NOWAIT) != 0) {
2009 MNT_REL(mp);
2010 MNT_IUNLOCK(mp);
2011 *mpp = NULL;
2012 return (EWOULDBLOCK);
2013 }
2014 /*
2015 * Wait for the suspension to finish.
2016 */
2017 mflags = 0;
2018 if ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0) {
2019 if ((flags & V_PCATCH) != 0)
2020 mflags |= PCATCH;
2021 }
2022 mflags |= (PUSER - 1) | PDROP;
2023 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, "suspfs", 0);
2024 vfs_rel(mp);
2025 if (error == 0)
2026 goto retry;
2027 *mpp = NULL;
2028 return (error);
2029 }
2030
2031 /*
2032 * Filesystem write operation has completed. If we are suspending and this
2033 * operation is the last one, notify the suspender that the suspension is
2034 * now in effect.
2035 */
2036 void
vn_finished_write(struct mount * mp)2037 vn_finished_write(struct mount *mp)
2038 {
2039 struct mount_pcpu *mpcpu;
2040 int c;
2041
2042 if (mp == NULL)
2043 return;
2044
2045 if (vfs_op_thread_enter(mp, mpcpu)) {
2046 vfs_mp_count_sub_pcpu(mpcpu, writeopcount, 1);
2047 vfs_mp_count_sub_pcpu(mpcpu, ref, 1);
2048 vfs_op_thread_exit(mp, mpcpu);
2049 return;
2050 }
2051
2052 MNT_ILOCK(mp);
2053 vfs_assert_mount_counters(mp);
2054 MNT_REL(mp);
2055 c = --mp->mnt_writeopcount;
2056 if (mp->mnt_vfs_ops == 0) {
2057 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0);
2058 MNT_IUNLOCK(mp);
2059 return;
2060 }
2061 if (c < 0)
2062 vfs_dump_mount_counters(mp);
2063 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && c == 0)
2064 wakeup(&mp->mnt_writeopcount);
2065 MNT_IUNLOCK(mp);
2066 }
2067
2068 /*
2069 * Filesystem secondary write operation has completed. If we are
2070 * suspending and this operation is the last one, notify the suspender
2071 * that the suspension is now in effect.
2072 */
2073 void
vn_finished_secondary_write(struct mount * mp)2074 vn_finished_secondary_write(struct mount *mp)
2075 {
2076 if (mp == NULL)
2077 return;
2078 MNT_ILOCK(mp);
2079 MNT_REL(mp);
2080 mp->mnt_secondary_writes--;
2081 if (mp->mnt_secondary_writes < 0)
2082 panic("vn_finished_secondary_write: neg cnt");
2083 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 &&
2084 mp->mnt_secondary_writes <= 0)
2085 wakeup(&mp->mnt_secondary_writes);
2086 MNT_IUNLOCK(mp);
2087 }
2088
2089 /*
2090 * Request a filesystem to suspend write operations.
2091 */
2092 int
vfs_write_suspend(struct mount * mp,int flags)2093 vfs_write_suspend(struct mount *mp, int flags)
2094 {
2095 int error;
2096
2097 vfs_op_enter(mp);
2098
2099 MNT_ILOCK(mp);
2100 vfs_assert_mount_counters(mp);
2101 if (mp->mnt_susp_owner == curthread) {
2102 vfs_op_exit_locked(mp);
2103 MNT_IUNLOCK(mp);
2104 return (EALREADY);
2105 }
2106 while (mp->mnt_kern_flag & MNTK_SUSPEND)
2107 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0);
2108
2109 /*
2110 * Unmount holds a write reference on the mount point. If we
2111 * own busy reference and drain for writers, we deadlock with
2112 * the reference draining in the unmount path. Callers of
2113 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if
2114 * vfs_busy() reference is owned and caller is not in the
2115 * unmount context.
2116 */
2117 if ((flags & VS_SKIP_UNMOUNT) != 0 &&
2118 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) {
2119 vfs_op_exit_locked(mp);
2120 MNT_IUNLOCK(mp);
2121 return (EBUSY);
2122 }
2123
2124 mp->mnt_kern_flag |= MNTK_SUSPEND;
2125 mp->mnt_susp_owner = curthread;
2126 if (mp->mnt_writeopcount > 0)
2127 (void) msleep(&mp->mnt_writeopcount,
2128 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0);
2129 else
2130 MNT_IUNLOCK(mp);
2131 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0) {
2132 vfs_write_resume(mp, 0);
2133 /* vfs_write_resume does vfs_op_exit() for us */
2134 }
2135 return (error);
2136 }
2137
2138 /*
2139 * Request a filesystem to resume write operations.
2140 */
2141 void
vfs_write_resume(struct mount * mp,int flags)2142 vfs_write_resume(struct mount *mp, int flags)
2143 {
2144
2145 MNT_ILOCK(mp);
2146 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
2147 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner"));
2148 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 |
2149 MNTK_SUSPENDED);
2150 mp->mnt_susp_owner = NULL;
2151 wakeup(&mp->mnt_writeopcount);
2152 wakeup(&mp->mnt_flag);
2153 curthread->td_pflags &= ~TDP_IGNSUSP;
2154 if ((flags & VR_START_WRITE) != 0) {
2155 MNT_REF(mp);
2156 mp->mnt_writeopcount++;
2157 }
2158 MNT_IUNLOCK(mp);
2159 if ((flags & VR_NO_SUSPCLR) == 0)
2160 VFS_SUSP_CLEAN(mp);
2161 vfs_op_exit(mp);
2162 } else if ((flags & VR_START_WRITE) != 0) {
2163 MNT_REF(mp);
2164 vn_start_write_refed(mp, 0, true);
2165 } else {
2166 MNT_IUNLOCK(mp);
2167 }
2168 }
2169
2170 /*
2171 * Helper loop around vfs_write_suspend() for filesystem unmount VFS
2172 * methods.
2173 */
2174 int
vfs_write_suspend_umnt(struct mount * mp)2175 vfs_write_suspend_umnt(struct mount *mp)
2176 {
2177 int error;
2178
2179 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0,
2180 ("vfs_write_suspend_umnt: recursed"));
2181
2182 /* dounmount() already called vn_start_write(). */
2183 for (;;) {
2184 vn_finished_write(mp);
2185 error = vfs_write_suspend(mp, 0);
2186 if (error != 0) {
2187 vn_start_write(NULL, &mp, V_WAIT);
2188 return (error);
2189 }
2190 MNT_ILOCK(mp);
2191 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0)
2192 break;
2193 MNT_IUNLOCK(mp);
2194 vn_start_write(NULL, &mp, V_WAIT);
2195 }
2196 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2);
2197 wakeup(&mp->mnt_flag);
2198 MNT_IUNLOCK(mp);
2199 curthread->td_pflags |= TDP_IGNSUSP;
2200 return (0);
2201 }
2202
2203 /*
2204 * Implement kqueues for files by translating it to vnode operation.
2205 */
2206 static int
vn_kqfilter(struct file * fp,struct knote * kn)2207 vn_kqfilter(struct file *fp, struct knote *kn)
2208 {
2209
2210 return (VOP_KQFILTER(fp->f_vnode, kn));
2211 }
2212
2213 int
vn_kqfilter_opath(struct file * fp,struct knote * kn)2214 vn_kqfilter_opath(struct file *fp, struct knote *kn)
2215 {
2216 if ((fp->f_flag & FKQALLOWED) == 0)
2217 return (EBADF);
2218 return (vn_kqfilter(fp, kn));
2219 }
2220
2221 /*
2222 * Simplified in-kernel wrapper calls for extended attribute access.
2223 * Both calls pass in a NULL credential, authorizing as "kernel" access.
2224 * Set IO_NODELOCKED in ioflg if the vnode is already locked.
2225 */
2226 int
vn_extattr_get(struct vnode * vp,int ioflg,int attrnamespace,const char * attrname,int * buflen,char * buf,struct thread * td)2227 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace,
2228 const char *attrname, int *buflen, char *buf, struct thread *td)
2229 {
2230 struct uio auio;
2231 struct iovec iov;
2232 int error;
2233
2234 iov.iov_len = *buflen;
2235 iov.iov_base = buf;
2236
2237 auio.uio_iov = &iov;
2238 auio.uio_iovcnt = 1;
2239 auio.uio_rw = UIO_READ;
2240 auio.uio_segflg = UIO_SYSSPACE;
2241 auio.uio_td = td;
2242 auio.uio_offset = 0;
2243 auio.uio_resid = *buflen;
2244
2245 if ((ioflg & IO_NODELOCKED) == 0)
2246 vn_lock(vp, LK_SHARED | LK_RETRY);
2247
2248 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
2249
2250 /* authorize attribute retrieval as kernel */
2251 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL,
2252 td);
2253
2254 if ((ioflg & IO_NODELOCKED) == 0)
2255 VOP_UNLOCK(vp);
2256
2257 if (error == 0) {
2258 *buflen = *buflen - auio.uio_resid;
2259 }
2260
2261 return (error);
2262 }
2263
2264 /*
2265 * XXX failure mode if partially written?
2266 */
2267 int
vn_extattr_set(struct vnode * vp,int ioflg,int attrnamespace,const char * attrname,int buflen,char * buf,struct thread * td)2268 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace,
2269 const char *attrname, int buflen, char *buf, struct thread *td)
2270 {
2271 struct uio auio;
2272 struct iovec iov;
2273 struct mount *mp;
2274 int error;
2275
2276 iov.iov_len = buflen;
2277 iov.iov_base = buf;
2278
2279 auio.uio_iov = &iov;
2280 auio.uio_iovcnt = 1;
2281 auio.uio_rw = UIO_WRITE;
2282 auio.uio_segflg = UIO_SYSSPACE;
2283 auio.uio_td = td;
2284 auio.uio_offset = 0;
2285 auio.uio_resid = buflen;
2286
2287 if ((ioflg & IO_NODELOCKED) == 0) {
2288 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0)
2289 return (error);
2290 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2291 }
2292
2293 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
2294
2295 /* authorize attribute setting as kernel */
2296 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td);
2297
2298 if ((ioflg & IO_NODELOCKED) == 0) {
2299 vn_finished_write(mp);
2300 VOP_UNLOCK(vp);
2301 }
2302
2303 return (error);
2304 }
2305
2306 int
vn_extattr_rm(struct vnode * vp,int ioflg,int attrnamespace,const char * attrname,struct thread * td)2307 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace,
2308 const char *attrname, struct thread *td)
2309 {
2310 struct mount *mp;
2311 int error;
2312
2313 if ((ioflg & IO_NODELOCKED) == 0) {
2314 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0)
2315 return (error);
2316 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2317 }
2318
2319 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
2320
2321 /* authorize attribute removal as kernel */
2322 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td);
2323 if (error == EOPNOTSUPP)
2324 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL,
2325 NULL, td);
2326
2327 if ((ioflg & IO_NODELOCKED) == 0) {
2328 vn_finished_write(mp);
2329 VOP_UNLOCK(vp);
2330 }
2331
2332 return (error);
2333 }
2334
2335 static int
vn_get_ino_alloc_vget(struct mount * mp,void * arg,int lkflags,struct vnode ** rvp)2336 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags,
2337 struct vnode **rvp)
2338 {
2339
2340 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp));
2341 }
2342
2343 int
vn_vget_ino(struct vnode * vp,ino_t ino,int lkflags,struct vnode ** rvp)2344 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp)
2345 {
2346
2347 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino,
2348 lkflags, rvp));
2349 }
2350
2351 int
vn_vget_ino_gen(struct vnode * vp,vn_get_ino_t alloc,void * alloc_arg,int lkflags,struct vnode ** rvp)2352 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg,
2353 int lkflags, struct vnode **rvp)
2354 {
2355 struct mount *mp;
2356 int ltype, error;
2357
2358 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get");
2359 mp = vp->v_mount;
2360 ltype = VOP_ISLOCKED(vp);
2361 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED,
2362 ("vn_vget_ino: vp not locked"));
2363 error = vfs_busy(mp, MBF_NOWAIT);
2364 if (error != 0) {
2365 vfs_ref(mp);
2366 VOP_UNLOCK(vp);
2367 error = vfs_busy(mp, 0);
2368 vn_lock(vp, ltype | LK_RETRY);
2369 vfs_rel(mp);
2370 if (error != 0)
2371 return (ENOENT);
2372 if (VN_IS_DOOMED(vp)) {
2373 vfs_unbusy(mp);
2374 return (ENOENT);
2375 }
2376 }
2377 VOP_UNLOCK(vp);
2378 error = alloc(mp, alloc_arg, lkflags, rvp);
2379 vfs_unbusy(mp);
2380 if (error != 0 || *rvp != vp)
2381 vn_lock(vp, ltype | LK_RETRY);
2382 if (VN_IS_DOOMED(vp)) {
2383 if (error == 0) {
2384 if (*rvp == vp)
2385 vunref(vp);
2386 else
2387 vput(*rvp);
2388 }
2389 error = ENOENT;
2390 }
2391 return (error);
2392 }
2393
2394 static void
vn_send_sigxfsz(struct proc * p)2395 vn_send_sigxfsz(struct proc *p)
2396 {
2397 PROC_LOCK(p);
2398 kern_psignal(p, SIGXFSZ);
2399 PROC_UNLOCK(p);
2400 }
2401
2402 int
vn_rlimit_trunc(u_quad_t size,struct thread * td)2403 vn_rlimit_trunc(u_quad_t size, struct thread *td)
2404 {
2405 if (size <= lim_cur(td, RLIMIT_FSIZE))
2406 return (0);
2407 vn_send_sigxfsz(td->td_proc);
2408 return (EFBIG);
2409 }
2410
2411 static int
vn_rlimit_fsizex1(const struct vnode * vp,struct uio * uio,off_t maxfsz,bool adj,struct thread * td)2412 vn_rlimit_fsizex1(const struct vnode *vp, struct uio *uio, off_t maxfsz,
2413 bool adj, struct thread *td)
2414 {
2415 off_t lim;
2416 bool ktr_write;
2417
2418 if (vp->v_type != VREG)
2419 return (0);
2420
2421 /*
2422 * Handle file system maximum file size.
2423 */
2424 if (maxfsz != 0 && uio->uio_offset + uio->uio_resid > maxfsz) {
2425 if (!adj || uio->uio_offset >= maxfsz)
2426 return (EFBIG);
2427 uio->uio_resid = maxfsz - uio->uio_offset;
2428 }
2429
2430 /*
2431 * This is kernel write (e.g. vnode_pager) or accounting
2432 * write, ignore limit.
2433 */
2434 if (td == NULL || (td->td_pflags2 & TDP2_ACCT) != 0)
2435 return (0);
2436
2437 /*
2438 * Calculate file size limit.
2439 */
2440 ktr_write = (td->td_pflags & TDP_INKTRACE) != 0;
2441 lim = __predict_false(ktr_write) ? td->td_ktr_io_lim :
2442 lim_cur(td, RLIMIT_FSIZE);
2443
2444 /*
2445 * Is the limit reached?
2446 */
2447 if (__predict_true((uoff_t)uio->uio_offset + uio->uio_resid <= lim))
2448 return (0);
2449
2450 /*
2451 * Prepared filesystems can handle writes truncated to the
2452 * file size limit.
2453 */
2454 if (adj && (uoff_t)uio->uio_offset < lim) {
2455 uio->uio_resid = lim - (uoff_t)uio->uio_offset;
2456 return (0);
2457 }
2458
2459 if (!ktr_write || ktr_filesize_limit_signal)
2460 vn_send_sigxfsz(td->td_proc);
2461 return (EFBIG);
2462 }
2463
2464 /*
2465 * Helper for VOP_WRITE() implementations, the common code to
2466 * handle maximum supported file size on the filesystem, and
2467 * RLIMIT_FSIZE, except for special writes from accounting subsystem
2468 * and ktrace.
2469 *
2470 * For maximum file size (maxfsz argument):
2471 * - return EFBIG if uio_offset is beyond it
2472 * - otherwise, clamp uio_resid if write would extend file beyond maxfsz.
2473 *
2474 * For RLIMIT_FSIZE:
2475 * - return EFBIG and send SIGXFSZ if uio_offset is beyond the limit
2476 * - otherwise, clamp uio_resid if write would extend file beyond limit.
2477 *
2478 * If clamping occured, the adjustment for uio_resid is stored in
2479 * *resid_adj, to be re-applied by vn_rlimit_fsizex_res() on return
2480 * from the VOP.
2481 */
2482 int
vn_rlimit_fsizex(const struct vnode * vp,struct uio * uio,off_t maxfsz,ssize_t * resid_adj,struct thread * td)2483 vn_rlimit_fsizex(const struct vnode *vp, struct uio *uio, off_t maxfsz,
2484 ssize_t *resid_adj, struct thread *td)
2485 {
2486 ssize_t resid_orig;
2487 int error;
2488 bool adj;
2489
2490 resid_orig = uio->uio_resid;
2491 adj = resid_adj != NULL;
2492 error = vn_rlimit_fsizex1(vp, uio, maxfsz, adj, td);
2493 if (adj)
2494 *resid_adj = resid_orig - uio->uio_resid;
2495 return (error);
2496 }
2497
2498 void
vn_rlimit_fsizex_res(struct uio * uio,ssize_t resid_adj)2499 vn_rlimit_fsizex_res(struct uio *uio, ssize_t resid_adj)
2500 {
2501 uio->uio_resid += resid_adj;
2502 }
2503
2504 int
vn_rlimit_fsize(const struct vnode * vp,const struct uio * uio,struct thread * td)2505 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio,
2506 struct thread *td)
2507 {
2508 return (vn_rlimit_fsizex(vp, __DECONST(struct uio *, uio), 0, NULL,
2509 td));
2510 }
2511
2512 int
vn_chmod(struct file * fp,mode_t mode,struct ucred * active_cred,struct thread * td)2513 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred,
2514 struct thread *td)
2515 {
2516 struct vnode *vp;
2517
2518 vp = fp->f_vnode;
2519 #ifdef AUDIT
2520 vn_lock(vp, LK_SHARED | LK_RETRY);
2521 AUDIT_ARG_VNODE1(vp);
2522 VOP_UNLOCK(vp);
2523 #endif
2524 return (setfmode(td, active_cred, vp, mode));
2525 }
2526
2527 int
vn_chown(struct file * fp,uid_t uid,gid_t gid,struct ucred * active_cred,struct thread * td)2528 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
2529 struct thread *td)
2530 {
2531 struct vnode *vp;
2532
2533 vp = fp->f_vnode;
2534 #ifdef AUDIT
2535 vn_lock(vp, LK_SHARED | LK_RETRY);
2536 AUDIT_ARG_VNODE1(vp);
2537 VOP_UNLOCK(vp);
2538 #endif
2539 return (setfown(td, active_cred, vp, uid, gid));
2540 }
2541
2542 /*
2543 * Remove pages in the range ["start", "end") from the vnode's VM object. If
2544 * "end" is 0, then the range extends to the end of the object.
2545 */
2546 void
vn_pages_remove(struct vnode * vp,vm_pindex_t start,vm_pindex_t end)2547 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end)
2548 {
2549 vm_object_t object;
2550
2551 if ((object = vp->v_object) == NULL)
2552 return;
2553 VM_OBJECT_WLOCK(object);
2554 vm_object_page_remove(object, start, end, 0);
2555 VM_OBJECT_WUNLOCK(object);
2556 }
2557
2558 /*
2559 * Like vn_pages_remove(), but skips invalid pages, which by definition are not
2560 * mapped into any process' address space. Filesystems may use this in
2561 * preference to vn_pages_remove() to avoid blocking on pages busied in
2562 * preparation for a VOP_GETPAGES.
2563 */
2564 void
vn_pages_remove_valid(struct vnode * vp,vm_pindex_t start,vm_pindex_t end)2565 vn_pages_remove_valid(struct vnode *vp, vm_pindex_t start, vm_pindex_t end)
2566 {
2567 vm_object_t object;
2568
2569 if ((object = vp->v_object) == NULL)
2570 return;
2571 VM_OBJECT_WLOCK(object);
2572 vm_object_page_remove(object, start, end, OBJPR_VALIDONLY);
2573 VM_OBJECT_WUNLOCK(object);
2574 }
2575
2576 int
vn_bmap_seekhole_locked(struct vnode * vp,u_long cmd,off_t * off,struct ucred * cred)2577 vn_bmap_seekhole_locked(struct vnode *vp, u_long cmd, off_t *off,
2578 struct ucred *cred)
2579 {
2580 off_t size;
2581 daddr_t bn, bnp;
2582 uint64_t bsize;
2583 off_t noff;
2584 int error;
2585
2586 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA,
2587 ("%s: Wrong command %lu", __func__, cmd));
2588 ASSERT_VOP_ELOCKED(vp, "vn_bmap_seekhole_locked");
2589
2590 if (vp->v_type != VREG) {
2591 error = ENOTTY;
2592 goto out;
2593 }
2594 error = vn_getsize_locked(vp, &size, cred);
2595 if (error != 0)
2596 goto out;
2597 noff = *off;
2598 if (noff < 0 || noff >= size) {
2599 error = ENXIO;
2600 goto out;
2601 }
2602
2603 /* See the comment in ufs_bmap_seekdata(). */
2604 vnode_pager_clean_sync(vp);
2605
2606 bsize = vp->v_mount->mnt_stat.f_iosize;
2607 for (bn = noff / bsize; noff < size; bn++, noff += bsize -
2608 noff % bsize) {
2609 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL);
2610 if (error == EOPNOTSUPP) {
2611 error = ENOTTY;
2612 goto out;
2613 }
2614 if ((bnp == -1 && cmd == FIOSEEKHOLE) ||
2615 (bnp != -1 && cmd == FIOSEEKDATA)) {
2616 noff = bn * bsize;
2617 if (noff < *off)
2618 noff = *off;
2619 goto out;
2620 }
2621 }
2622 if (noff > size)
2623 noff = size;
2624 /* noff == size. There is an implicit hole at the end of file. */
2625 if (cmd == FIOSEEKDATA)
2626 error = ENXIO;
2627 out:
2628 if (error == 0)
2629 *off = noff;
2630 return (error);
2631 }
2632
2633 int
vn_bmap_seekhole(struct vnode * vp,u_long cmd,off_t * off,struct ucred * cred)2634 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred)
2635 {
2636 int error;
2637
2638 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA,
2639 ("%s: Wrong command %lu", __func__, cmd));
2640
2641 if (vn_lock(vp, LK_EXCLUSIVE) != 0)
2642 return (EBADF);
2643 error = vn_bmap_seekhole_locked(vp, cmd, off, cred);
2644 VOP_UNLOCK(vp);
2645 return (error);
2646 }
2647
2648 int
vn_seek(struct file * fp,off_t offset,int whence,struct thread * td)2649 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td)
2650 {
2651 struct ucred *cred;
2652 struct vnode *vp;
2653 off_t foffset, fsize, size;
2654 int error, noneg;
2655
2656 cred = td->td_ucred;
2657 vp = fp->f_vnode;
2658 noneg = (vp->v_type != VCHR);
2659 /*
2660 * Try to dodge locking for common case of querying the offset.
2661 */
2662 if (whence == L_INCR && offset == 0) {
2663 foffset = foffset_read(fp);
2664 if (__predict_false(foffset < 0 && noneg)) {
2665 return (EOVERFLOW);
2666 }
2667 td->td_uretoff.tdu_off = foffset;
2668 return (0);
2669 }
2670 foffset = foffset_lock(fp, 0);
2671 error = 0;
2672 switch (whence) {
2673 case L_INCR:
2674 if (noneg &&
2675 (foffset < 0 ||
2676 (offset > 0 && foffset > OFF_MAX - offset))) {
2677 error = EOVERFLOW;
2678 break;
2679 }
2680 offset += foffset;
2681 break;
2682 case L_XTND:
2683 error = vn_getsize(vp, &fsize, cred);
2684 if (error != 0)
2685 break;
2686
2687 /*
2688 * If the file references a disk device, then fetch
2689 * the media size and use that to determine the ending
2690 * offset.
2691 */
2692 if (fsize == 0 && vp->v_type == VCHR &&
2693 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0)
2694 fsize = size;
2695 if (noneg && offset > 0 && fsize > OFF_MAX - offset) {
2696 error = EOVERFLOW;
2697 break;
2698 }
2699 offset += fsize;
2700 break;
2701 case L_SET:
2702 break;
2703 case SEEK_DATA:
2704 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td);
2705 if (error == ENOTTY)
2706 error = EINVAL;
2707 break;
2708 case SEEK_HOLE:
2709 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td);
2710 if (error == ENOTTY)
2711 error = EINVAL;
2712 break;
2713 default:
2714 error = EINVAL;
2715 }
2716 if (error == 0 && noneg && offset < 0)
2717 error = EINVAL;
2718 if (error != 0)
2719 goto drop;
2720 VFS_KNOTE_UNLOCKED(vp, 0);
2721 td->td_uretoff.tdu_off = offset;
2722 drop:
2723 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0);
2724 return (error);
2725 }
2726
2727 int
vn_utimes_perm(struct vnode * vp,struct vattr * vap,struct ucred * cred,struct thread * td)2728 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred,
2729 struct thread *td)
2730 {
2731 int error;
2732
2733 /*
2734 * Grant permission if the caller is the owner of the file, or
2735 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on
2736 * on the file. If the time pointer is null, then write
2737 * permission on the file is also sufficient.
2738 *
2739 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes:
2740 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES
2741 * will be allowed to set the times [..] to the current
2742 * server time.
2743 */
2744 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td);
2745 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0)
2746 error = VOP_ACCESS(vp, VWRITE, cred, td);
2747 return (error);
2748 }
2749
2750 int
vn_fill_kinfo(struct file * fp,struct kinfo_file * kif,struct filedesc * fdp)2751 vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
2752 {
2753 struct vnode *vp;
2754 int error;
2755
2756 if (fp->f_type == DTYPE_FIFO)
2757 kif->kf_type = KF_TYPE_FIFO;
2758 else
2759 kif->kf_type = KF_TYPE_VNODE;
2760 vp = fp->f_vnode;
2761 vref(vp);
2762 FILEDESC_SUNLOCK(fdp);
2763 error = vn_fill_kinfo_vnode(vp, kif);
2764 vrele(vp);
2765 FILEDESC_SLOCK(fdp);
2766 return (error);
2767 }
2768
2769 static inline void
vn_fill_junk(struct kinfo_file * kif)2770 vn_fill_junk(struct kinfo_file *kif)
2771 {
2772 size_t len, olen;
2773
2774 /*
2775 * Simulate vn_fullpath returning changing values for a given
2776 * vp during e.g. coredump.
2777 */
2778 len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1;
2779 olen = strlen(kif->kf_path);
2780 if (len < olen)
2781 strcpy(&kif->kf_path[len - 1], "$");
2782 else
2783 for (; olen < len; olen++)
2784 strcpy(&kif->kf_path[olen], "A");
2785 }
2786
2787 int
vn_fill_kinfo_vnode(struct vnode * vp,struct kinfo_file * kif)2788 vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif)
2789 {
2790 struct vattr va;
2791 char *fullpath, *freepath;
2792 int error;
2793
2794 kif->kf_un.kf_file.kf_file_type = vntype_to_kinfo(vp->v_type);
2795 freepath = NULL;
2796 fullpath = "-";
2797 error = vn_fullpath(vp, &fullpath, &freepath);
2798 if (error == 0) {
2799 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path));
2800 }
2801 if (freepath != NULL)
2802 free(freepath, M_TEMP);
2803
2804 KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path,
2805 vn_fill_junk(kif);
2806 );
2807
2808 /*
2809 * Retrieve vnode attributes.
2810 */
2811 va.va_fsid = VNOVAL;
2812 va.va_rdev = NODEV;
2813 vn_lock(vp, LK_SHARED | LK_RETRY);
2814 error = VOP_GETATTR(vp, &va, curthread->td_ucred);
2815 VOP_UNLOCK(vp);
2816 if (error != 0)
2817 return (error);
2818 if (va.va_fsid != VNOVAL)
2819 kif->kf_un.kf_file.kf_file_fsid = va.va_fsid;
2820 else
2821 kif->kf_un.kf_file.kf_file_fsid =
2822 vp->v_mount->mnt_stat.f_fsid.val[0];
2823 kif->kf_un.kf_file.kf_file_fsid_freebsd11 =
2824 kif->kf_un.kf_file.kf_file_fsid; /* truncate */
2825 kif->kf_un.kf_file.kf_file_fileid = va.va_fileid;
2826 kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode);
2827 kif->kf_un.kf_file.kf_file_size = va.va_size;
2828 kif->kf_un.kf_file.kf_file_rdev = va.va_rdev;
2829 kif->kf_un.kf_file.kf_file_rdev_freebsd11 =
2830 kif->kf_un.kf_file.kf_file_rdev; /* truncate */
2831 kif->kf_un.kf_file.kf_file_nlink = va.va_nlink;
2832 return (0);
2833 }
2834
2835 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)2836 vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size,
2837 vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff,
2838 struct thread *td)
2839 {
2840 #ifdef HWPMC_HOOKS
2841 struct pmckern_map_in pkm;
2842 #endif
2843 struct mount *mp;
2844 struct vnode *vp;
2845 vm_object_t object;
2846 vm_prot_t maxprot;
2847 boolean_t writecounted;
2848 int error;
2849
2850 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \
2851 defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4)
2852 /*
2853 * POSIX shared-memory objects are defined to have
2854 * kernel persistence, and are not defined to support
2855 * read(2)/write(2) -- or even open(2). Thus, we can
2856 * use MAP_ASYNC to trade on-disk coherence for speed.
2857 * The shm_open(3) library routine turns on the FPOSIXSHM
2858 * flag to request this behavior.
2859 */
2860 if ((fp->f_flag & FPOSIXSHM) != 0)
2861 flags |= MAP_NOSYNC;
2862 #endif
2863 vp = fp->f_vnode;
2864
2865 /*
2866 * Ensure that file and memory protections are
2867 * compatible. Note that we only worry about
2868 * writability if mapping is shared; in this case,
2869 * current and max prot are dictated by the open file.
2870 * XXX use the vnode instead? Problem is: what
2871 * credentials do we use for determination? What if
2872 * proc does a setuid?
2873 */
2874 mp = vp->v_mount;
2875 if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) {
2876 maxprot = VM_PROT_NONE;
2877 if ((prot & VM_PROT_EXECUTE) != 0)
2878 return (EACCES);
2879 } else
2880 maxprot = VM_PROT_EXECUTE;
2881 if ((fp->f_flag & FREAD) != 0)
2882 maxprot |= VM_PROT_READ;
2883 else if ((prot & VM_PROT_READ) != 0)
2884 return (EACCES);
2885
2886 /*
2887 * If we are sharing potential changes via MAP_SHARED and we
2888 * are trying to get write permission although we opened it
2889 * without asking for it, bail out.
2890 */
2891 if ((flags & MAP_SHARED) != 0) {
2892 if ((fp->f_flag & FWRITE) != 0)
2893 maxprot |= VM_PROT_WRITE;
2894 else if ((prot & VM_PROT_WRITE) != 0)
2895 return (EACCES);
2896 } else {
2897 maxprot |= VM_PROT_WRITE;
2898 cap_maxprot |= VM_PROT_WRITE;
2899 }
2900 maxprot &= cap_maxprot;
2901
2902 /*
2903 * For regular files and shared memory, POSIX requires that
2904 * the value of foff be a legitimate offset within the data
2905 * object. In particular, negative offsets are invalid.
2906 * Blocking negative offsets and overflows here avoids
2907 * possible wraparound or user-level access into reserved
2908 * ranges of the data object later. In contrast, POSIX does
2909 * not dictate how offsets are used by device drivers, so in
2910 * the case of a device mapping a negative offset is passed
2911 * on.
2912 */
2913 if (
2914 #ifdef _LP64
2915 size > OFF_MAX ||
2916 #endif
2917 foff > OFF_MAX - size)
2918 return (EINVAL);
2919
2920 writecounted = FALSE;
2921 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp,
2922 &foff, &object, &writecounted);
2923 if (error != 0)
2924 return (error);
2925 error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object,
2926 foff, writecounted, td);
2927 if (error != 0) {
2928 /*
2929 * If this mapping was accounted for in the vnode's
2930 * writecount, then undo that now.
2931 */
2932 if (writecounted)
2933 vm_pager_release_writecount(object, 0, size);
2934 vm_object_deallocate(object);
2935 }
2936 #ifdef HWPMC_HOOKS
2937 /* Inform hwpmc(4) if an executable is being mapped. */
2938 if (PMC_HOOK_INSTALLED(PMC_FN_MMAP)) {
2939 if ((prot & VM_PROT_EXECUTE) != 0 && error == 0) {
2940 pkm.pm_file = vp;
2941 pkm.pm_address = (uintptr_t) *addr;
2942 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_MMAP, (void *) &pkm);
2943 }
2944 }
2945 #endif
2946 return (error);
2947 }
2948
2949 void
vn_fsid(struct vnode * vp,struct vattr * va)2950 vn_fsid(struct vnode *vp, struct vattr *va)
2951 {
2952 fsid_t *f;
2953
2954 f = &vp->v_mount->mnt_stat.f_fsid;
2955 va->va_fsid = (uint32_t)f->val[1];
2956 va->va_fsid <<= sizeof(f->val[1]) * NBBY;
2957 va->va_fsid += (uint32_t)f->val[0];
2958 }
2959
2960 int
vn_fsync_buf(struct vnode * vp,int waitfor)2961 vn_fsync_buf(struct vnode *vp, int waitfor)
2962 {
2963 struct buf *bp, *nbp;
2964 struct bufobj *bo;
2965 struct mount *mp;
2966 int error, maxretry;
2967
2968 error = 0;
2969 maxretry = 10000; /* large, arbitrarily chosen */
2970 mp = NULL;
2971 if (vp->v_type == VCHR) {
2972 VI_LOCK(vp);
2973 mp = vp->v_rdev->si_mountpt;
2974 VI_UNLOCK(vp);
2975 }
2976 bo = &vp->v_bufobj;
2977 BO_LOCK(bo);
2978 loop1:
2979 /*
2980 * MARK/SCAN initialization to avoid infinite loops.
2981 */
2982 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) {
2983 bp->b_vflags &= ~BV_SCANNED;
2984 bp->b_error = 0;
2985 }
2986
2987 /*
2988 * Flush all dirty buffers associated with a vnode.
2989 */
2990 loop2:
2991 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
2992 if ((bp->b_vflags & BV_SCANNED) != 0)
2993 continue;
2994 bp->b_vflags |= BV_SCANNED;
2995 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL)) {
2996 if (waitfor != MNT_WAIT)
2997 continue;
2998 if (BUF_LOCK(bp,
2999 LK_EXCLUSIVE | LK_INTERLOCK | LK_SLEEPFAIL,
3000 BO_LOCKPTR(bo)) != 0) {
3001 BO_LOCK(bo);
3002 goto loop1;
3003 }
3004 BO_LOCK(bo);
3005 }
3006 BO_UNLOCK(bo);
3007 KASSERT(bp->b_bufobj == bo,
3008 ("bp %p wrong b_bufobj %p should be %p",
3009 bp, bp->b_bufobj, bo));
3010 if ((bp->b_flags & B_DELWRI) == 0)
3011 panic("fsync: not dirty");
3012 if ((vp->v_object != NULL) && (bp->b_flags & B_CLUSTEROK)) {
3013 vfs_bio_awrite(bp);
3014 } else {
3015 bremfree(bp);
3016 bawrite(bp);
3017 }
3018 if (maxretry < 1000)
3019 pause("dirty", hz < 1000 ? 1 : hz / 1000);
3020 BO_LOCK(bo);
3021 goto loop2;
3022 }
3023
3024 /*
3025 * If synchronous the caller expects us to completely resolve all
3026 * dirty buffers in the system. Wait for in-progress I/O to
3027 * complete (which could include background bitmap writes), then
3028 * retry if dirty blocks still exist.
3029 */
3030 if (waitfor == MNT_WAIT) {
3031 bufobj_wwait(bo, 0, 0);
3032 if (bo->bo_dirty.bv_cnt > 0) {
3033 /*
3034 * If we are unable to write any of these buffers
3035 * then we fail now rather than trying endlessly
3036 * to write them out.
3037 */
3038 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs)
3039 if ((error = bp->b_error) != 0)
3040 break;
3041 if ((mp != NULL && mp->mnt_secondary_writes > 0) ||
3042 (error == 0 && --maxretry >= 0))
3043 goto loop1;
3044 if (error == 0)
3045 error = EAGAIN;
3046 }
3047 }
3048 BO_UNLOCK(bo);
3049 if (error != 0)
3050 vn_printf(vp, "fsync: giving up on dirty (error = %d) ", error);
3051
3052 return (error);
3053 }
3054
3055 /*
3056 * Copies a byte range from invp to outvp. Calls VOP_COPY_FILE_RANGE()
3057 * or vn_generic_copy_file_range() after rangelocking the byte ranges,
3058 * to do the actual copy.
3059 * vn_generic_copy_file_range() is factored out, so it can be called
3060 * from a VOP_COPY_FILE_RANGE() call as well, but handles vnodes from
3061 * different file systems.
3062 */
3063 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)3064 vn_copy_file_range(struct vnode *invp, off_t *inoffp, struct vnode *outvp,
3065 off_t *outoffp, size_t *lenp, unsigned int flags, struct ucred *incred,
3066 struct ucred *outcred, struct thread *fsize_td)
3067 {
3068 struct mount *inmp, *outmp;
3069 struct vnode *invpl, *outvpl;
3070 int error;
3071 size_t len;
3072 uint64_t uval;
3073
3074 invpl = outvpl = NULL;
3075 len = *lenp;
3076 *lenp = 0; /* For error returns. */
3077 error = 0;
3078
3079 /* Do some sanity checks on the arguments. */
3080 if (invp->v_type == VDIR || outvp->v_type == VDIR)
3081 error = EISDIR;
3082 else if (*inoffp < 0 || *outoffp < 0 ||
3083 invp->v_type != VREG || outvp->v_type != VREG)
3084 error = EINVAL;
3085 if (error != 0)
3086 goto out;
3087
3088 /* Ensure offset + len does not wrap around. */
3089 uval = *inoffp;
3090 uval += len;
3091 if (uval > INT64_MAX)
3092 len = INT64_MAX - *inoffp;
3093 uval = *outoffp;
3094 uval += len;
3095 if (uval > INT64_MAX)
3096 len = INT64_MAX - *outoffp;
3097 if (len == 0)
3098 goto out;
3099
3100 error = VOP_GETLOWVNODE(invp, &invpl, FREAD);
3101 if (error != 0)
3102 goto out;
3103 error = VOP_GETLOWVNODE(outvp, &outvpl, FWRITE);
3104 if (error != 0)
3105 goto out1;
3106
3107 inmp = invpl->v_mount;
3108 outmp = outvpl->v_mount;
3109 if (inmp == NULL || outmp == NULL)
3110 goto out2;
3111
3112 for (;;) {
3113 error = vfs_busy(inmp, 0);
3114 if (error != 0)
3115 goto out2;
3116 if (inmp == outmp)
3117 break;
3118 error = vfs_busy(outmp, MBF_NOWAIT);
3119 if (error != 0) {
3120 vfs_unbusy(inmp);
3121 error = vfs_busy(outmp, 0);
3122 if (error == 0) {
3123 vfs_unbusy(outmp);
3124 continue;
3125 }
3126 goto out2;
3127 }
3128 break;
3129 }
3130
3131 /*
3132 * If the two vnodes are for the same file system type, call
3133 * VOP_COPY_FILE_RANGE(), otherwise call vn_generic_copy_file_range()
3134 * which can handle copies across multiple file system types.
3135 */
3136 *lenp = len;
3137 if (inmp == outmp || inmp->mnt_vfc == outmp->mnt_vfc)
3138 error = VOP_COPY_FILE_RANGE(invpl, inoffp, outvpl, outoffp,
3139 lenp, flags, incred, outcred, fsize_td);
3140 else
3141 error = ENOSYS;
3142 if (error == ENOSYS)
3143 error = vn_generic_copy_file_range(invpl, inoffp, outvpl,
3144 outoffp, lenp, flags, incred, outcred, fsize_td);
3145 vfs_unbusy(outmp);
3146 if (inmp != outmp)
3147 vfs_unbusy(inmp);
3148 out2:
3149 if (outvpl != NULL)
3150 vrele(outvpl);
3151 out1:
3152 if (invpl != NULL)
3153 vrele(invpl);
3154 out:
3155 return (error);
3156 }
3157
3158 /*
3159 * Test len bytes of data starting at dat for all bytes == 0.
3160 * Return true if all bytes are zero, false otherwise.
3161 * Expects dat to be well aligned.
3162 */
3163 static bool
mem_iszero(void * dat,int len)3164 mem_iszero(void *dat, int len)
3165 {
3166 int i;
3167 const u_int *p;
3168 const char *cp;
3169
3170 for (p = dat; len > 0; len -= sizeof(*p), p++) {
3171 if (len >= sizeof(*p)) {
3172 if (*p != 0)
3173 return (false);
3174 } else {
3175 cp = (const char *)p;
3176 for (i = 0; i < len; i++, cp++)
3177 if (*cp != '\0')
3178 return (false);
3179 }
3180 }
3181 return (true);
3182 }
3183
3184 /*
3185 * Look for a hole in the output file and, if found, adjust *outoffp
3186 * and *xferp to skip past the hole.
3187 * *xferp is the entire hole length to be written and xfer2 is how many bytes
3188 * to be written as 0's upon return.
3189 */
3190 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)3191 vn_skip_hole(struct vnode *outvp, off_t xfer2, off_t *outoffp, off_t *xferp,
3192 off_t *dataoffp, off_t *holeoffp, struct ucred *cred)
3193 {
3194 int error;
3195 off_t delta;
3196
3197 if (*holeoffp == 0 || *holeoffp <= *outoffp) {
3198 *dataoffp = *outoffp;
3199 error = VOP_IOCTL(outvp, FIOSEEKDATA, dataoffp, 0, cred,
3200 curthread);
3201 if (error == 0) {
3202 *holeoffp = *dataoffp;
3203 error = VOP_IOCTL(outvp, FIOSEEKHOLE, holeoffp, 0, cred,
3204 curthread);
3205 }
3206 if (error != 0 || *holeoffp == *dataoffp) {
3207 /*
3208 * Since outvp is unlocked, it may be possible for
3209 * another thread to do a truncate(), lseek(), write()
3210 * creating a hole at startoff between the above
3211 * VOP_IOCTL() calls, if the other thread does not do
3212 * rangelocking.
3213 * If that happens, *holeoffp == *dataoffp and finding
3214 * the hole has failed, so disable vn_skip_hole().
3215 */
3216 *holeoffp = -1; /* Disable use of vn_skip_hole(). */
3217 return (xfer2);
3218 }
3219 KASSERT(*dataoffp >= *outoffp,
3220 ("vn_skip_hole: dataoff=%jd < outoff=%jd",
3221 (intmax_t)*dataoffp, (intmax_t)*outoffp));
3222 KASSERT(*holeoffp > *dataoffp,
3223 ("vn_skip_hole: holeoff=%jd <= dataoff=%jd",
3224 (intmax_t)*holeoffp, (intmax_t)*dataoffp));
3225 }
3226
3227 /*
3228 * If there is a hole before the data starts, advance *outoffp and
3229 * *xferp past the hole.
3230 */
3231 if (*dataoffp > *outoffp) {
3232 delta = *dataoffp - *outoffp;
3233 if (delta >= *xferp) {
3234 /* Entire *xferp is a hole. */
3235 *outoffp += *xferp;
3236 *xferp = 0;
3237 return (0);
3238 }
3239 *xferp -= delta;
3240 *outoffp += delta;
3241 xfer2 = MIN(xfer2, *xferp);
3242 }
3243
3244 /*
3245 * If a hole starts before the end of this xfer2, reduce this xfer2 so
3246 * that the write ends at the start of the hole.
3247 * *holeoffp should always be greater than *outoffp, but for the
3248 * non-INVARIANTS case, check this to make sure xfer2 remains a sane
3249 * value.
3250 */
3251 if (*holeoffp > *outoffp && *holeoffp < *outoffp + xfer2)
3252 xfer2 = *holeoffp - *outoffp;
3253 return (xfer2);
3254 }
3255
3256 /*
3257 * Write an xfer sized chunk to outvp in blksize blocks from dat.
3258 * dat is a maximum of blksize in length and can be written repeatedly in
3259 * the chunk.
3260 * If growfile == true, just grow the file via vn_truncate_locked() instead
3261 * of doing actual writes.
3262 * If checkhole == true, a hole is being punched, so skip over any hole
3263 * already in the output file.
3264 */
3265 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)3266 vn_write_outvp(struct vnode *outvp, char *dat, off_t outoff, off_t xfer,
3267 u_long blksize, bool growfile, bool checkhole, struct ucred *cred)
3268 {
3269 struct mount *mp;
3270 off_t dataoff, holeoff, xfer2;
3271 int error;
3272
3273 /*
3274 * Loop around doing writes of blksize until write has been completed.
3275 * Lock/unlock on each loop iteration so that a bwillwrite() can be
3276 * done for each iteration, since the xfer argument can be very
3277 * large if there is a large hole to punch in the output file.
3278 */
3279 error = 0;
3280 holeoff = 0;
3281 do {
3282 xfer2 = MIN(xfer, blksize);
3283 if (checkhole) {
3284 /*
3285 * Punching a hole. Skip writing if there is
3286 * already a hole in the output file.
3287 */
3288 xfer2 = vn_skip_hole(outvp, xfer2, &outoff, &xfer,
3289 &dataoff, &holeoff, cred);
3290 if (xfer == 0)
3291 break;
3292 if (holeoff < 0)
3293 checkhole = false;
3294 KASSERT(xfer2 > 0, ("vn_write_outvp: xfer2=%jd",
3295 (intmax_t)xfer2));
3296 }
3297 bwillwrite();
3298 mp = NULL;
3299 error = vn_start_write(outvp, &mp, V_WAIT);
3300 if (error != 0)
3301 break;
3302 if (growfile) {
3303 error = vn_lock(outvp, LK_EXCLUSIVE);
3304 if (error == 0) {
3305 error = vn_truncate_locked(outvp, outoff + xfer,
3306 false, cred);
3307 VOP_UNLOCK(outvp);
3308 }
3309 } else {
3310 error = vn_lock(outvp, vn_lktype_write(mp, outvp));
3311 if (error == 0) {
3312 error = vn_rdwr(UIO_WRITE, outvp, dat, xfer2,
3313 outoff, UIO_SYSSPACE, IO_NODELOCKED,
3314 curthread->td_ucred, cred, NULL, curthread);
3315 outoff += xfer2;
3316 xfer -= xfer2;
3317 VOP_UNLOCK(outvp);
3318 }
3319 }
3320 if (mp != NULL)
3321 vn_finished_write(mp);
3322 } while (!growfile && xfer > 0 && error == 0);
3323 return (error);
3324 }
3325
3326 /*
3327 * Copy a byte range of one file to another. This function can handle the
3328 * case where invp and outvp are on different file systems.
3329 * It can also be called by a VOP_COPY_FILE_RANGE() to do the work, if there
3330 * is no better file system specific way to do it.
3331 */
3332 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)3333 vn_generic_copy_file_range(struct vnode *invp, off_t *inoffp,
3334 struct vnode *outvp, off_t *outoffp, size_t *lenp, unsigned int flags,
3335 struct ucred *incred, struct ucred *outcred, struct thread *fsize_td)
3336 {
3337 struct vattr inva;
3338 struct mount *mp;
3339 off_t startoff, endoff, xfer, xfer2;
3340 u_long blksize;
3341 int error, interrupted;
3342 bool cantseek, readzeros, eof, first, lastblock, holetoeof, sparse;
3343 ssize_t aresid, r = 0;
3344 size_t copylen, len, savlen;
3345 off_t outsize;
3346 char *dat;
3347 long holein, holeout;
3348 struct timespec curts, endts;
3349
3350 holein = holeout = 0;
3351 savlen = len = *lenp;
3352 error = 0;
3353 interrupted = 0;
3354 dat = NULL;
3355
3356 error = vn_lock(invp, LK_SHARED);
3357 if (error != 0)
3358 goto out;
3359 if (VOP_PATHCONF(invp, _PC_MIN_HOLE_SIZE, &holein) != 0)
3360 holein = 0;
3361 error = VOP_GETATTR(invp, &inva, incred);
3362 if (error == 0 && inva.va_size > OFF_MAX)
3363 error = EFBIG;
3364 VOP_UNLOCK(invp);
3365 if (error != 0)
3366 goto out;
3367
3368 /*
3369 * Use va_bytes >= va_size as a hint that the file does not have
3370 * sufficient holes to justify the overhead of doing FIOSEEKHOLE.
3371 * This hint does not work well for file systems doing compression
3372 * and may fail when allocations for extended attributes increases
3373 * the value of va_bytes to >= va_size.
3374 */
3375 sparse = true;
3376 if (holein != 0 && inva.va_bytes >= inva.va_size) {
3377 holein = 0;
3378 sparse = false;
3379 }
3380
3381 mp = NULL;
3382 error = vn_start_write(outvp, &mp, V_WAIT);
3383 if (error == 0)
3384 error = vn_lock(outvp, LK_EXCLUSIVE);
3385 if (error == 0) {
3386 /*
3387 * If fsize_td != NULL, do a vn_rlimit_fsizex() call,
3388 * now that outvp is locked.
3389 */
3390 if (fsize_td != NULL) {
3391 struct uio io;
3392
3393 io.uio_offset = *outoffp;
3394 io.uio_resid = len;
3395 error = vn_rlimit_fsizex(outvp, &io, 0, &r, fsize_td);
3396 len = savlen = io.uio_resid;
3397 /*
3398 * No need to call vn_rlimit_fsizex_res before return,
3399 * since the uio is local.
3400 */
3401 }
3402 if (VOP_PATHCONF(outvp, _PC_MIN_HOLE_SIZE, &holeout) != 0)
3403 holeout = 0;
3404 /*
3405 * Holes that are past EOF do not need to be written as a block
3406 * of zero bytes. So, truncate the output file as far as
3407 * possible and then use size to decide if writing 0
3408 * bytes is necessary in the loop below.
3409 */
3410 if (error == 0)
3411 error = vn_getsize_locked(outvp, &outsize, outcred);
3412 if (error == 0 && outsize > *outoffp &&
3413 *outoffp <= OFF_MAX - len && outsize <= *outoffp + len &&
3414 *inoffp < inva.va_size &&
3415 *outoffp <= OFF_MAX - (inva.va_size - *inoffp) &&
3416 outsize <= *outoffp + (inva.va_size - *inoffp)) {
3417 #ifdef MAC
3418 error = mac_vnode_check_write(curthread->td_ucred,
3419 outcred, outvp);
3420 if (error == 0)
3421 #endif
3422 error = vn_truncate_locked(outvp, *outoffp,
3423 false, outcred);
3424 if (error == 0)
3425 outsize = *outoffp;
3426 }
3427 VOP_UNLOCK(outvp);
3428 }
3429 if (mp != NULL)
3430 vn_finished_write(mp);
3431 if (error != 0)
3432 goto out;
3433
3434 if (sparse && holein == 0 && holeout > 0) {
3435 /*
3436 * For this special case, the input data will be scanned
3437 * for blocks of all 0 bytes. For these blocks, the
3438 * write can be skipped for the output file to create
3439 * an unallocated region.
3440 * Therefore, use the appropriate size for the output file.
3441 */
3442 blksize = holeout;
3443 if (blksize <= 512) {
3444 /*
3445 * Use f_iosize, since ZFS reports a _PC_MIN_HOLE_SIZE
3446 * of 512, although it actually only creates
3447 * unallocated regions for blocks >= f_iosize.
3448 */
3449 blksize = outvp->v_mount->mnt_stat.f_iosize;
3450 }
3451 } else {
3452 /*
3453 * Use the larger of the two f_iosize values. If they are
3454 * not the same size, one will normally be an exact multiple of
3455 * the other, since they are both likely to be a power of 2.
3456 */
3457 blksize = MAX(invp->v_mount->mnt_stat.f_iosize,
3458 outvp->v_mount->mnt_stat.f_iosize);
3459 }
3460
3461 /* Clip to sane limits. */
3462 if (blksize < 4096)
3463 blksize = 4096;
3464 else if (blksize > maxphys)
3465 blksize = maxphys;
3466 dat = malloc(blksize, M_TEMP, M_WAITOK);
3467
3468 /*
3469 * If VOP_IOCTL(FIOSEEKHOLE) works for invp, use it and FIOSEEKDATA
3470 * to find holes. Otherwise, just scan the read block for all 0s
3471 * in the inner loop where the data copying is done.
3472 * Note that some file systems such as NFSv3, NFSv4.0 and NFSv4.1 may
3473 * support holes on the server, but do not support FIOSEEKHOLE.
3474 * The kernel flag COPY_FILE_RANGE_TIMEO1SEC is used to indicate
3475 * that this function should return after 1second with a partial
3476 * completion.
3477 */
3478 if ((flags & COPY_FILE_RANGE_TIMEO1SEC) != 0) {
3479 getnanouptime(&endts);
3480 endts.tv_sec++;
3481 } else
3482 timespecclear(&endts);
3483 first = true;
3484 holetoeof = eof = false;
3485 while (len > 0 && error == 0 && !eof && interrupted == 0) {
3486 endoff = 0; /* To shut up compilers. */
3487 cantseek = true;
3488 startoff = *inoffp;
3489 copylen = len;
3490
3491 /*
3492 * Find the next data area. If there is just a hole to EOF,
3493 * FIOSEEKDATA should fail with ENXIO.
3494 * (I do not know if any file system will report a hole to
3495 * EOF via FIOSEEKHOLE, but I am pretty sure FIOSEEKDATA
3496 * will fail for those file systems.)
3497 *
3498 * For input files that don't support FIOSEEKDATA/FIOSEEKHOLE,
3499 * the code just falls through to the inner copy loop.
3500 */
3501 error = EINVAL;
3502 if (holein > 0) {
3503 error = VOP_IOCTL(invp, FIOSEEKDATA, &startoff, 0,
3504 incred, curthread);
3505 if (error == ENXIO) {
3506 startoff = endoff = inva.va_size;
3507 eof = holetoeof = true;
3508 error = 0;
3509 }
3510 }
3511 if (error == 0 && !holetoeof) {
3512 endoff = startoff;
3513 error = VOP_IOCTL(invp, FIOSEEKHOLE, &endoff, 0,
3514 incred, curthread);
3515 /*
3516 * Since invp is unlocked, it may be possible for
3517 * another thread to do a truncate(), lseek(), write()
3518 * creating a hole at startoff between the above
3519 * VOP_IOCTL() calls, if the other thread does not do
3520 * rangelocking.
3521 * If that happens, startoff == endoff and finding
3522 * the hole has failed, so set an error.
3523 */
3524 if (error == 0 && startoff == endoff)
3525 error = EINVAL; /* Any error. Reset to 0. */
3526 }
3527 if (error == 0) {
3528 if (startoff > *inoffp) {
3529 /* Found hole before data block. */
3530 xfer = MIN(startoff - *inoffp, len);
3531 if (*outoffp < outsize) {
3532 /* Must write 0s to punch hole. */
3533 xfer2 = MIN(outsize - *outoffp,
3534 xfer);
3535 memset(dat, 0, MIN(xfer2, blksize));
3536 error = vn_write_outvp(outvp, dat,
3537 *outoffp, xfer2, blksize, false,
3538 holeout > 0, outcred);
3539 }
3540
3541 if (error == 0 && *outoffp + xfer >
3542 outsize && (xfer == len || holetoeof)) {
3543 /* Grow output file (hole at end). */
3544 error = vn_write_outvp(outvp, dat,
3545 *outoffp, xfer, blksize, true,
3546 false, outcred);
3547 }
3548 if (error == 0) {
3549 *inoffp += xfer;
3550 *outoffp += xfer;
3551 len -= xfer;
3552 if (len < savlen) {
3553 interrupted = sig_intr();
3554 if (timespecisset(&endts) &&
3555 interrupted == 0) {
3556 getnanouptime(&curts);
3557 if (timespeccmp(&curts,
3558 &endts, >=))
3559 interrupted =
3560 EINTR;
3561 }
3562 }
3563 }
3564 }
3565 copylen = MIN(len, endoff - startoff);
3566 cantseek = false;
3567 } else {
3568 cantseek = true;
3569 if (!sparse)
3570 cantseek = false;
3571 startoff = *inoffp;
3572 copylen = len;
3573 error = 0;
3574 }
3575
3576 xfer = blksize;
3577 if (cantseek) {
3578 /*
3579 * Set first xfer to end at a block boundary, so that
3580 * holes are more likely detected in the loop below via
3581 * the for all bytes 0 method.
3582 */
3583 xfer -= (*inoffp % blksize);
3584 }
3585
3586 /*
3587 * Loop copying the data block. If this was our first attempt
3588 * to copy anything, allow a zero-length block so that the VOPs
3589 * get a chance to update metadata, specifically the atime.
3590 */
3591 while (error == 0 && ((copylen > 0 && !eof) || first) &&
3592 interrupted == 0) {
3593 if (copylen < xfer)
3594 xfer = copylen;
3595 first = false;
3596 error = vn_lock(invp, LK_SHARED);
3597 if (error != 0)
3598 goto out;
3599 error = vn_rdwr(UIO_READ, invp, dat, xfer,
3600 startoff, UIO_SYSSPACE, IO_NODELOCKED,
3601 curthread->td_ucred, incred, &aresid,
3602 curthread);
3603 VOP_UNLOCK(invp);
3604 lastblock = false;
3605 if (error == 0 && (xfer == 0 || aresid > 0)) {
3606 /* Stop the copy at EOF on the input file. */
3607 xfer -= aresid;
3608 eof = true;
3609 lastblock = true;
3610 }
3611 if (error == 0) {
3612 /*
3613 * Skip the write for holes past the initial EOF
3614 * of the output file, unless this is the last
3615 * write of the output file at EOF.
3616 */
3617 readzeros = cantseek ? mem_iszero(dat, xfer) :
3618 false;
3619 if (xfer == len)
3620 lastblock = true;
3621 if (!cantseek || *outoffp < outsize ||
3622 lastblock || !readzeros)
3623 error = vn_write_outvp(outvp, dat,
3624 *outoffp, xfer, blksize,
3625 readzeros && lastblock &&
3626 *outoffp >= outsize, false,
3627 outcred);
3628 if (error == 0) {
3629 *inoffp += xfer;
3630 startoff += xfer;
3631 *outoffp += xfer;
3632 copylen -= xfer;
3633 len -= xfer;
3634 if (len < savlen) {
3635 interrupted = sig_intr();
3636 if (timespecisset(&endts) &&
3637 interrupted == 0) {
3638 getnanouptime(&curts);
3639 if (timespeccmp(&curts,
3640 &endts, >=))
3641 interrupted =
3642 EINTR;
3643 }
3644 }
3645 }
3646 }
3647 xfer = blksize;
3648 }
3649 }
3650 out:
3651 *lenp = savlen - len;
3652 free(dat, M_TEMP);
3653 return (error);
3654 }
3655
3656 static int
vn_fallocate(struct file * fp,off_t offset,off_t len,struct thread * td)3657 vn_fallocate(struct file *fp, off_t offset, off_t len, struct thread *td)
3658 {
3659 struct mount *mp;
3660 struct vnode *vp;
3661 off_t olen, ooffset;
3662 int error;
3663 #ifdef AUDIT
3664 int audited_vnode1 = 0;
3665 #endif
3666
3667 vp = fp->f_vnode;
3668 if (vp->v_type != VREG)
3669 return (ENODEV);
3670
3671 /* Allocating blocks may take a long time, so iterate. */
3672 for (;;) {
3673 olen = len;
3674 ooffset = offset;
3675
3676 bwillwrite();
3677 mp = NULL;
3678 error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH);
3679 if (error != 0)
3680 break;
3681 error = vn_lock(vp, LK_EXCLUSIVE);
3682 if (error != 0) {
3683 vn_finished_write(mp);
3684 break;
3685 }
3686 #ifdef AUDIT
3687 if (!audited_vnode1) {
3688 AUDIT_ARG_VNODE1(vp);
3689 audited_vnode1 = 1;
3690 }
3691 #endif
3692 #ifdef MAC
3693 error = mac_vnode_check_write(td->td_ucred, fp->f_cred, vp);
3694 if (error == 0)
3695 #endif
3696 error = VOP_ALLOCATE(vp, &offset, &len, 0,
3697 td->td_ucred);
3698 VOP_UNLOCK(vp);
3699 vn_finished_write(mp);
3700
3701 if (olen + ooffset != offset + len) {
3702 panic("offset + len changed from %jx/%jx to %jx/%jx",
3703 ooffset, olen, offset, len);
3704 }
3705 if (error != 0 || len == 0)
3706 break;
3707 KASSERT(olen > len, ("Iteration did not make progress?"));
3708 maybe_yield();
3709 }
3710
3711 return (error);
3712 }
3713
3714 static int
vn_deallocate_impl(struct vnode * vp,off_t * offset,off_t * length,int flags,int ioflag,struct ucred * cred,struct ucred * active_cred,struct ucred * file_cred)3715 vn_deallocate_impl(struct vnode *vp, off_t *offset, off_t *length, int flags,
3716 int ioflag, struct ucred *cred, struct ucred *active_cred,
3717 struct ucred *file_cred)
3718 {
3719 struct mount *mp;
3720 void *rl_cookie;
3721 off_t off, len;
3722 int error;
3723 #ifdef AUDIT
3724 bool audited_vnode1 = false;
3725 #endif
3726
3727 rl_cookie = NULL;
3728 error = 0;
3729 mp = NULL;
3730 off = *offset;
3731 len = *length;
3732
3733 if ((ioflag & (IO_NODELOCKED | IO_RANGELOCKED)) == 0)
3734 rl_cookie = vn_rangelock_wlock(vp, off, off + len);
3735 while (len > 0 && error == 0) {
3736 /*
3737 * Try to deallocate the longest range in one pass.
3738 * In case a pass takes too long to be executed, it returns
3739 * partial result. The residue will be proceeded in the next
3740 * pass.
3741 */
3742
3743 if ((ioflag & IO_NODELOCKED) == 0) {
3744 bwillwrite();
3745 if ((error = vn_start_write(vp, &mp,
3746 V_WAIT | V_PCATCH)) != 0)
3747 goto out;
3748 vn_lock(vp, vn_lktype_write(mp, vp) | LK_RETRY);
3749 }
3750 #ifdef AUDIT
3751 if (!audited_vnode1) {
3752 AUDIT_ARG_VNODE1(vp);
3753 audited_vnode1 = true;
3754 }
3755 #endif
3756
3757 #ifdef MAC
3758 if ((ioflag & IO_NOMACCHECK) == 0)
3759 error = mac_vnode_check_write(active_cred, file_cred,
3760 vp);
3761 #endif
3762 if (error == 0)
3763 error = VOP_DEALLOCATE(vp, &off, &len, flags, ioflag,
3764 cred);
3765
3766 if ((ioflag & IO_NODELOCKED) == 0) {
3767 VOP_UNLOCK(vp);
3768 if (mp != NULL) {
3769 vn_finished_write(mp);
3770 mp = NULL;
3771 }
3772 }
3773 if (error == 0 && len != 0)
3774 maybe_yield();
3775 }
3776 out:
3777 if (rl_cookie != NULL)
3778 vn_rangelock_unlock(vp, rl_cookie);
3779 *offset = off;
3780 *length = len;
3781 return (error);
3782 }
3783
3784 /*
3785 * This function is supposed to be used in the situations where the deallocation
3786 * is not triggered by a user request.
3787 */
3788 int
vn_deallocate(struct vnode * vp,off_t * offset,off_t * length,int flags,int ioflag,struct ucred * active_cred,struct ucred * file_cred)3789 vn_deallocate(struct vnode *vp, off_t *offset, off_t *length, int flags,
3790 int ioflag, struct ucred *active_cred, struct ucred *file_cred)
3791 {
3792 struct ucred *cred;
3793
3794 if (*offset < 0 || *length <= 0 || *length > OFF_MAX - *offset ||
3795 flags != 0)
3796 return (EINVAL);
3797 if (vp->v_type != VREG)
3798 return (ENODEV);
3799
3800 cred = file_cred != NOCRED ? file_cred : active_cred;
3801 return (vn_deallocate_impl(vp, offset, length, flags, ioflag, cred,
3802 active_cred, file_cred));
3803 }
3804
3805 static int
vn_fspacectl(struct file * fp,int cmd,off_t * offset,off_t * length,int flags,struct ucred * active_cred,struct thread * td)3806 vn_fspacectl(struct file *fp, int cmd, off_t *offset, off_t *length, int flags,
3807 struct ucred *active_cred, struct thread *td)
3808 {
3809 int error;
3810 struct vnode *vp;
3811 int ioflag;
3812
3813 KASSERT(cmd == SPACECTL_DEALLOC, ("vn_fspacectl: Invalid cmd"));
3814 KASSERT((flags & ~SPACECTL_F_SUPPORTED) == 0,
3815 ("vn_fspacectl: non-zero flags"));
3816 KASSERT(*offset >= 0 && *length > 0 && *length <= OFF_MAX - *offset,
3817 ("vn_fspacectl: offset/length overflow or underflow"));
3818 vp = fp->f_vnode;
3819
3820 if (vp->v_type != VREG)
3821 return (ENODEV);
3822
3823 ioflag = get_write_ioflag(fp);
3824
3825 switch (cmd) {
3826 case SPACECTL_DEALLOC:
3827 error = vn_deallocate_impl(vp, offset, length, flags, ioflag,
3828 active_cred, active_cred, fp->f_cred);
3829 break;
3830 default:
3831 panic("vn_fspacectl: unknown cmd %d", cmd);
3832 }
3833
3834 return (error);
3835 }
3836
3837 /*
3838 * Keep this assert as long as sizeof(struct dirent) is used as the maximum
3839 * entry size.
3840 */
3841 _Static_assert(_GENERIC_MAXDIRSIZ == sizeof(struct dirent),
3842 "'struct dirent' size must be a multiple of its alignment "
3843 "(see _GENERIC_DIRLEN())");
3844
3845 /*
3846 * Returns successive directory entries through some caller's provided buffer.
3847 *
3848 * This function automatically refills the provided buffer with calls to
3849 * VOP_READDIR() (after MAC permission checks).
3850 *
3851 * 'td' is used for credentials and passed to uiomove(). 'dirbuf' is the
3852 * caller's buffer to fill and 'dirbuflen' its allocated size. 'dirbuf' must
3853 * be properly aligned to access 'struct dirent' structures and 'dirbuflen'
3854 * must be greater than GENERIC_MAXDIRSIZ to avoid VOP_READDIR() returning
3855 * EINVAL (the latter is not a strong guarantee (yet); but EINVAL will always
3856 * be returned if this requirement is not verified). '*dpp' points to the
3857 * current directory entry in the buffer and '*len' contains the remaining
3858 * valid bytes in 'dirbuf' after 'dpp' (including the pointed entry).
3859 *
3860 * At first call (or when restarting the read), '*len' must have been set to 0,
3861 * '*off' to 0 (or any valid start offset) and '*eofflag' to 0. There are no
3862 * more entries as soon as '*len' is 0 after a call that returned 0. Calling
3863 * again this function after such a condition is considered an error and EINVAL
3864 * will be returned. Other possible error codes are those of VOP_READDIR(),
3865 * EINTEGRITY if the returned entries do not pass coherency tests, or EINVAL
3866 * (bad call). All errors are unrecoverable, i.e., the state ('*len', '*off'
3867 * and '*eofflag') must be re-initialized before a subsequent call. On error
3868 * or at end of directory, '*dpp' is reset to NULL.
3869 *
3870 * '*len', '*off' and '*eofflag' are internal state the caller should not
3871 * tamper with except as explained above. '*off' is the next directory offset
3872 * to read from to refill the buffer. '*eofflag' is set to 0 or 1 by the last
3873 * internal call to VOP_READDIR() that returned without error, indicating
3874 * whether it reached the end of the directory, and to 2 by this function after
3875 * all entries have been read.
3876 */
3877 int
vn_dir_next_dirent(struct vnode * vp,struct thread * td,char * dirbuf,size_t dirbuflen,struct dirent ** dpp,size_t * len,off_t * off,int * eofflag)3878 vn_dir_next_dirent(struct vnode *vp, struct thread *td,
3879 char *dirbuf, size_t dirbuflen,
3880 struct dirent **dpp, size_t *len, off_t *off, int *eofflag)
3881 {
3882 struct dirent *dp = NULL;
3883 int reclen;
3884 int error;
3885 struct uio uio;
3886 struct iovec iov;
3887
3888 ASSERT_VOP_LOCKED(vp, "vnode not locked");
3889 VNASSERT(vp->v_type == VDIR, vp, ("vnode is not a directory"));
3890 MPASS2((uintptr_t)dirbuf < (uintptr_t)dirbuf + dirbuflen,
3891 "Address space overflow");
3892
3893 if (__predict_false(dirbuflen < GENERIC_MAXDIRSIZ)) {
3894 /* Don't take any chances in this case */
3895 error = EINVAL;
3896 goto out;
3897 }
3898
3899 if (*len != 0) {
3900 dp = *dpp;
3901
3902 /*
3903 * The caller continued to call us after an error (we set dp to
3904 * NULL in a previous iteration). Bail out right now.
3905 */
3906 if (__predict_false(dp == NULL))
3907 return (EINVAL);
3908
3909 MPASS(*len <= dirbuflen);
3910 MPASS2((uintptr_t)dirbuf <= (uintptr_t)dp &&
3911 (uintptr_t)dp + *len <= (uintptr_t)dirbuf + dirbuflen,
3912 "Filled range not inside buffer");
3913
3914 reclen = dp->d_reclen;
3915 if (reclen >= *len) {
3916 /* End of buffer reached */
3917 *len = 0;
3918 } else {
3919 dp = (struct dirent *)((char *)dp + reclen);
3920 *len -= reclen;
3921 }
3922 }
3923
3924 if (*len == 0) {
3925 dp = NULL;
3926
3927 /* Have to refill. */
3928 switch (*eofflag) {
3929 case 0:
3930 break;
3931
3932 case 1:
3933 /* Nothing more to read. */
3934 *eofflag = 2; /* Remember the caller reached EOF. */
3935 goto success;
3936
3937 default:
3938 /* The caller didn't test for EOF. */
3939 error = EINVAL;
3940 goto out;
3941 }
3942
3943 iov.iov_base = dirbuf;
3944 iov.iov_len = dirbuflen;
3945
3946 uio.uio_iov = &iov;
3947 uio.uio_iovcnt = 1;
3948 uio.uio_offset = *off;
3949 uio.uio_resid = dirbuflen;
3950 uio.uio_segflg = UIO_SYSSPACE;
3951 uio.uio_rw = UIO_READ;
3952 uio.uio_td = td;
3953
3954 #ifdef MAC
3955 error = mac_vnode_check_readdir(td->td_ucred, vp);
3956 if (error == 0)
3957 #endif
3958 error = VOP_READDIR(vp, &uio, td->td_ucred, eofflag,
3959 NULL, NULL);
3960 if (error != 0)
3961 goto out;
3962
3963 *len = dirbuflen - uio.uio_resid;
3964 *off = uio.uio_offset;
3965
3966 if (*len == 0) {
3967 /* Sanity check on INVARIANTS. */
3968 MPASS(*eofflag != 0);
3969 *eofflag = 1;
3970 goto success;
3971 }
3972
3973 /*
3974 * Normalize the flag returned by VOP_READDIR(), since we use 2
3975 * as a sentinel value.
3976 */
3977 if (*eofflag != 0)
3978 *eofflag = 1;
3979
3980 dp = (struct dirent *)dirbuf;
3981 }
3982
3983 if (__predict_false(*len < GENERIC_MINDIRSIZ ||
3984 dp->d_reclen < GENERIC_MINDIRSIZ)) {
3985 error = EINTEGRITY;
3986 dp = NULL;
3987 goto out;
3988 }
3989
3990 success:
3991 error = 0;
3992 out:
3993 *dpp = dp;
3994 return (error);
3995 }
3996
3997 /*
3998 * Checks whether a directory is empty or not.
3999 *
4000 * If the directory is empty, returns 0, and if it is not, ENOTEMPTY. Other
4001 * values are genuine errors preventing the check.
4002 */
4003 int
vn_dir_check_empty(struct vnode * vp)4004 vn_dir_check_empty(struct vnode *vp)
4005 {
4006 struct thread *const td = curthread;
4007 char *dirbuf;
4008 size_t dirbuflen, len;
4009 off_t off;
4010 int eofflag, error;
4011 struct dirent *dp;
4012 struct vattr va;
4013
4014 ASSERT_VOP_LOCKED(vp, "vfs_emptydir");
4015 VNPASS(vp->v_type == VDIR, vp);
4016
4017 error = VOP_GETATTR(vp, &va, td->td_ucred);
4018 if (error != 0)
4019 return (error);
4020
4021 dirbuflen = max(DEV_BSIZE, GENERIC_MAXDIRSIZ);
4022 if (dirbuflen < va.va_blocksize)
4023 dirbuflen = va.va_blocksize;
4024 dirbuf = malloc(dirbuflen, M_TEMP, M_WAITOK);
4025
4026 len = 0;
4027 off = 0;
4028 eofflag = 0;
4029
4030 for (;;) {
4031 error = vn_dir_next_dirent(vp, td, dirbuf, dirbuflen,
4032 &dp, &len, &off, &eofflag);
4033 if (error != 0)
4034 goto end;
4035
4036 if (len == 0) {
4037 /* EOF */
4038 error = 0;
4039 goto end;
4040 }
4041
4042 /*
4043 * Skip whiteouts. Unionfs operates on filesystems only and
4044 * not on hierarchies, so these whiteouts would be shadowed on
4045 * the system hierarchy but not for a union using the
4046 * filesystem of their directories as the upper layer.
4047 * Additionally, unionfs currently transparently exposes
4048 * union-specific metadata of its upper layer, meaning that
4049 * whiteouts can be seen through the union view in empty
4050 * directories. Taking into account these whiteouts would then
4051 * prevent mounting another filesystem on such effectively
4052 * empty directories.
4053 */
4054 if (dp->d_type == DT_WHT)
4055 continue;
4056
4057 /*
4058 * Any file in the directory which is not '.' or '..' indicates
4059 * the directory is not empty.
4060 */
4061 switch (dp->d_namlen) {
4062 case 2:
4063 if (dp->d_name[1] != '.') {
4064 /* Can't be '..' (nor '.') */
4065 error = ENOTEMPTY;
4066 goto end;
4067 }
4068 /* FALLTHROUGH */
4069 case 1:
4070 if (dp->d_name[0] != '.') {
4071 /* Can't be '..' nor '.' */
4072 error = ENOTEMPTY;
4073 goto end;
4074 }
4075 break;
4076
4077 default:
4078 error = ENOTEMPTY;
4079 goto end;
4080 }
4081 }
4082
4083 end:
4084 free(dirbuf, M_TEMP);
4085 return (error);
4086 }
4087
4088
4089 static u_long vn_lock_pair_pause_cnt;
4090 SYSCTL_ULONG(_debug, OID_AUTO, vn_lock_pair_pause, CTLFLAG_RD,
4091 &vn_lock_pair_pause_cnt, 0,
4092 "Count of vn_lock_pair deadlocks");
4093
4094 u_int vn_lock_pair_pause_max;
4095 SYSCTL_UINT(_debug, OID_AUTO, vn_lock_pair_pause_max, CTLFLAG_RW,
4096 &vn_lock_pair_pause_max, 0,
4097 "Max ticks for vn_lock_pair deadlock avoidance sleep");
4098
4099 static void
vn_lock_pair_pause(const char * wmesg)4100 vn_lock_pair_pause(const char *wmesg)
4101 {
4102 atomic_add_long(&vn_lock_pair_pause_cnt, 1);
4103 pause(wmesg, prng32_bounded(vn_lock_pair_pause_max));
4104 }
4105
4106 /*
4107 * Lock pair of (possibly same) vnodes vp1, vp2, avoiding lock order
4108 * reversal. vp1_locked indicates whether vp1 is locked; if not, vp1
4109 * must be unlocked. Same for vp2 and vp2_locked. One of the vnodes
4110 * can be NULL.
4111 *
4112 * The function returns with both vnodes exclusively or shared locked,
4113 * according to corresponding lkflags, and guarantees that it does not
4114 * create lock order reversal with other threads during its execution.
4115 * Both vnodes could be unlocked temporary (and reclaimed).
4116 *
4117 * If requesting shared locking, locked vnode lock must not be recursed.
4118 *
4119 * Only one of LK_SHARED and LK_EXCLUSIVE must be specified.
4120 * LK_NODDLKTREAT can be optionally passed.
4121 *
4122 * If vp1 == vp2, only one, most exclusive, lock is obtained on it.
4123 */
4124 void
vn_lock_pair(struct vnode * vp1,bool vp1_locked,int lkflags1,struct vnode * vp2,bool vp2_locked,int lkflags2)4125 vn_lock_pair(struct vnode *vp1, bool vp1_locked, int lkflags1,
4126 struct vnode *vp2, bool vp2_locked, int lkflags2)
4127 {
4128 int error, locked1;
4129
4130 MPASS((((lkflags1 & LK_SHARED) != 0) ^ ((lkflags1 & LK_EXCLUSIVE) != 0)) ||
4131 (vp1 == NULL && lkflags1 == 0));
4132 MPASS((lkflags1 & ~(LK_SHARED | LK_EXCLUSIVE | LK_NODDLKTREAT)) == 0);
4133 MPASS((((lkflags2 & LK_SHARED) != 0) ^ ((lkflags2 & LK_EXCLUSIVE) != 0)) ||
4134 (vp2 == NULL && lkflags2 == 0));
4135 MPASS((lkflags2 & ~(LK_SHARED | LK_EXCLUSIVE | LK_NODDLKTREAT)) == 0);
4136
4137 if (vp1 == NULL && vp2 == NULL)
4138 return;
4139
4140 if (vp1 == vp2) {
4141 MPASS(vp1_locked == vp2_locked);
4142
4143 /* Select the most exclusive mode for lock. */
4144 if ((lkflags1 & LK_TYPE_MASK) != (lkflags2 & LK_TYPE_MASK))
4145 lkflags1 = (lkflags1 & ~LK_SHARED) | LK_EXCLUSIVE;
4146
4147 if (vp1_locked) {
4148 ASSERT_VOP_LOCKED(vp1, "vp1");
4149
4150 /* No need to relock if any lock is exclusive. */
4151 if ((vp1->v_vnlock->lock_object.lo_flags &
4152 LK_NOSHARE) != 0)
4153 return;
4154
4155 locked1 = VOP_ISLOCKED(vp1);
4156 if (((lkflags1 & LK_SHARED) != 0 &&
4157 locked1 != LK_EXCLUSIVE) ||
4158 ((lkflags1 & LK_EXCLUSIVE) != 0 &&
4159 locked1 == LK_EXCLUSIVE))
4160 return;
4161 VOP_UNLOCK(vp1);
4162 }
4163
4164 ASSERT_VOP_UNLOCKED(vp1, "vp1");
4165 vn_lock(vp1, lkflags1 | LK_RETRY);
4166 return;
4167 }
4168
4169 if (vp1 != NULL) {
4170 if ((lkflags1 & LK_SHARED) != 0 &&
4171 (vp1->v_vnlock->lock_object.lo_flags & LK_NOSHARE) != 0)
4172 lkflags1 = (lkflags1 & ~LK_SHARED) | LK_EXCLUSIVE;
4173 if (vp1_locked && VOP_ISLOCKED(vp1) != LK_EXCLUSIVE) {
4174 ASSERT_VOP_LOCKED(vp1, "vp1");
4175 if ((lkflags1 & LK_EXCLUSIVE) != 0) {
4176 VOP_UNLOCK(vp1);
4177 ASSERT_VOP_UNLOCKED(vp1,
4178 "vp1 shared recursed");
4179 vp1_locked = false;
4180 }
4181 } else if (!vp1_locked)
4182 ASSERT_VOP_UNLOCKED(vp1, "vp1");
4183 } else {
4184 vp1_locked = true;
4185 }
4186
4187 if (vp2 != NULL) {
4188 if ((lkflags2 & LK_SHARED) != 0 &&
4189 (vp2->v_vnlock->lock_object.lo_flags & LK_NOSHARE) != 0)
4190 lkflags2 = (lkflags2 & ~LK_SHARED) | LK_EXCLUSIVE;
4191 if (vp2_locked && VOP_ISLOCKED(vp2) != LK_EXCLUSIVE) {
4192 ASSERT_VOP_LOCKED(vp2, "vp2");
4193 if ((lkflags2 & LK_EXCLUSIVE) != 0) {
4194 VOP_UNLOCK(vp2);
4195 ASSERT_VOP_UNLOCKED(vp2,
4196 "vp2 shared recursed");
4197 vp2_locked = false;
4198 }
4199 } else if (!vp2_locked)
4200 ASSERT_VOP_UNLOCKED(vp2, "vp2");
4201 } else {
4202 vp2_locked = true;
4203 }
4204
4205 if (!vp1_locked && !vp2_locked) {
4206 vn_lock(vp1, lkflags1 | LK_RETRY);
4207 vp1_locked = true;
4208 }
4209
4210 while (!vp1_locked || !vp2_locked) {
4211 if (vp1_locked && vp2 != NULL) {
4212 if (vp1 != NULL) {
4213 error = VOP_LOCK1(vp2, lkflags2 | LK_NOWAIT,
4214 __FILE__, __LINE__);
4215 if (error == 0)
4216 break;
4217 VOP_UNLOCK(vp1);
4218 vp1_locked = false;
4219 vn_lock_pair_pause("vlp1");
4220 }
4221 vn_lock(vp2, lkflags2 | LK_RETRY);
4222 vp2_locked = true;
4223 }
4224 if (vp2_locked && vp1 != NULL) {
4225 if (vp2 != NULL) {
4226 error = VOP_LOCK1(vp1, lkflags1 | LK_NOWAIT,
4227 __FILE__, __LINE__);
4228 if (error == 0)
4229 break;
4230 VOP_UNLOCK(vp2);
4231 vp2_locked = false;
4232 vn_lock_pair_pause("vlp2");
4233 }
4234 vn_lock(vp1, lkflags1 | LK_RETRY);
4235 vp1_locked = true;
4236 }
4237 }
4238 if (vp1 != NULL) {
4239 if (lkflags1 == LK_EXCLUSIVE)
4240 ASSERT_VOP_ELOCKED(vp1, "vp1 ret");
4241 else
4242 ASSERT_VOP_LOCKED(vp1, "vp1 ret");
4243 }
4244 if (vp2 != NULL) {
4245 if (lkflags2 == LK_EXCLUSIVE)
4246 ASSERT_VOP_ELOCKED(vp2, "vp2 ret");
4247 else
4248 ASSERT_VOP_LOCKED(vp2, "vp2 ret");
4249 }
4250 }
4251
4252 int
vn_lktype_write(struct mount * mp,struct vnode * vp)4253 vn_lktype_write(struct mount *mp, struct vnode *vp)
4254 {
4255 if (MNT_SHARED_WRITES(mp) ||
4256 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount)))
4257 return (LK_SHARED);
4258 return (LK_EXCLUSIVE);
4259 }
4260
4261 int
vn_cmp(struct file * fp1,struct file * fp2,struct thread * td)4262 vn_cmp(struct file *fp1, struct file *fp2, struct thread *td)
4263 {
4264 if (fp2->f_type != DTYPE_VNODE)
4265 return (3);
4266 return (kcmp_cmp((uintptr_t)fp1->f_vnode, (uintptr_t)fp2->f_vnode));
4267 }
4268