xref: /dragonfly/sys/vfs/tmpfs/tmpfs_vnops.c (revision cd1c6085)
1 /*-
2  * Copyright (c) 2005, 2006 The NetBSD Foundation, Inc.
3  * All rights reserved.
4  *
5  * This code is derived from software contributed to The NetBSD Foundation
6  * by Julio M. Merino Vidal, developed as part of Google's Summer of Code
7  * 2005 program.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
20  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
22  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28  * POSSIBILITY OF SUCH DAMAGE.
29  *
30  * $NetBSD: tmpfs_vnops.c,v 1.39 2007/07/23 15:41:01 jmmv Exp $
31  */
32 
33 /*
34  * tmpfs vnode interface.
35  */
36 
37 #include <sys/kernel.h>
38 #include <sys/kern_syscall.h>
39 #include <sys/param.h>
40 #include <sys/fcntl.h>
41 #include <sys/lockf.h>
42 #include <sys/priv.h>
43 #include <sys/proc.h>
44 #include <sys/resourcevar.h>
45 #include <sys/sched.h>
46 #include <sys/stat.h>
47 #include <sys/systm.h>
48 #include <sys/unistd.h>
49 #include <sys/vfsops.h>
50 #include <sys/vnode.h>
51 #include <sys/mountctl.h>
52 
53 #include <vm/vm.h>
54 #include <vm/vm_extern.h>
55 #include <vm/vm_object.h>
56 #include <vm/vm_page.h>
57 #include <vm/vm_pageout.h>
58 #include <vm/vm_pager.h>
59 #include <vm/swap_pager.h>
60 
61 #include <sys/buf2.h>
62 #include <vm/vm_page2.h>
63 
64 #include <vfs/fifofs/fifo.h>
65 #include <vfs/tmpfs/tmpfs_vnops.h>
66 #include "tmpfs.h"
67 
68 static void tmpfs_strategy_done(struct bio *bio);
69 
70 static __inline
71 void
72 tmpfs_knote(struct vnode *vp, int flags)
73 {
74 	if (flags)
75 		KNOTE(&vp->v_pollinfo.vpi_kqinfo.ki_note, flags);
76 }
77 
78 
79 /* --------------------------------------------------------------------- */
80 
81 static int
82 tmpfs_nresolve(struct vop_nresolve_args *v)
83 {
84 	struct vnode *dvp = v->a_dvp;
85 	struct vnode *vp = NULL;
86 	struct namecache *ncp = v->a_nch->ncp;
87 	struct tmpfs_node *tnode;
88 	struct mount *mp;
89 	struct tmpfs_dirent *de;
90 	struct tmpfs_node *dnode;
91 	int error;
92 
93 	mp = dvp->v_mount;
94 
95 	dnode = VP_TO_TMPFS_DIR(dvp);
96 
97 	TMPFS_NODE_LOCK_SH(dnode);
98 	de = tmpfs_dir_lookup(dnode, NULL, ncp);
99 	if (de == NULL) {
100 		error = ENOENT;
101 	} else {
102 		/*
103 		 * Allocate a vnode for the node we found.
104 		 */
105 		tnode = de->td_node;
106 		error = tmpfs_alloc_vp(dvp->v_mount, tnode,
107 				       LK_EXCLUSIVE | LK_RETRY, &vp);
108 		if (error)
109 			goto out;
110 		KKASSERT(vp);
111 	}
112 
113 out:
114 	TMPFS_NODE_UNLOCK(dnode);
115 
116 	if ((dnode->tn_status & TMPFS_NODE_ACCESSED) == 0) {
117 		TMPFS_NODE_LOCK(dnode);
118 		dnode->tn_status |= TMPFS_NODE_ACCESSED;
119 		TMPFS_NODE_UNLOCK(dnode);
120 	}
121 
122 	/*
123 	 * Store the result of this lookup in the cache.  Avoid this if the
124 	 * request was for creation, as it does not improve timings on
125 	 * emprical tests.
126 	 */
127 	if (vp) {
128 		vn_unlock(vp);
129 		cache_setvp(v->a_nch, vp);
130 		vrele(vp);
131 	} else if (error == ENOENT) {
132 		cache_setvp(v->a_nch, NULL);
133 	}
134 	return (error);
135 }
136 
137 static int
138 tmpfs_nlookupdotdot(struct vop_nlookupdotdot_args *v)
139 {
140 	struct vnode *dvp = v->a_dvp;
141 	struct vnode **vpp = v->a_vpp;
142 	struct tmpfs_node *dnode = VP_TO_TMPFS_NODE(dvp);
143 	struct ucred *cred = v->a_cred;
144 	struct mount *mp;
145 	int error;
146 
147 	*vpp = NULL;
148 
149 	mp = dvp->v_mount;
150 
151 	/* Check accessibility of requested node as a first step. */
152 	error = VOP_ACCESS(dvp, VEXEC, cred);
153 	if (error != 0)
154 		return error;
155 
156 	if (dnode->tn_dir.tn_parent != NULL) {
157 		/* Allocate a new vnode on the matching entry. */
158 		error = tmpfs_alloc_vp(dvp->v_mount, dnode->tn_dir.tn_parent,
159 				       LK_EXCLUSIVE | LK_RETRY, vpp);
160 
161 		if (*vpp)
162 			vn_unlock(*vpp);
163 	}
164 	return (*vpp == NULL) ? ENOENT : 0;
165 }
166 
167 /* --------------------------------------------------------------------- */
168 
169 static int
170 tmpfs_ncreate(struct vop_ncreate_args *v)
171 {
172 	struct vnode *dvp = v->a_dvp;
173 	struct vnode **vpp = v->a_vpp;
174 	struct namecache *ncp = v->a_nch->ncp;
175 	struct vattr *vap = v->a_vap;
176 	struct ucred *cred = v->a_cred;
177 	struct mount *mp;
178 	int error;
179 
180 	mp = dvp->v_mount;
181 
182 	KKASSERT(vap->va_type == VREG || vap->va_type == VSOCK);
183 
184 	error = tmpfs_alloc_file(dvp, vpp, vap, ncp, cred, NULL);
185 	if (error == 0) {
186 		cache_setunresolved(v->a_nch);
187 		cache_setvp(v->a_nch, *vpp);
188 		tmpfs_knote(dvp, NOTE_WRITE);
189 	}
190 	return (error);
191 }
192 /* --------------------------------------------------------------------- */
193 
194 static int
195 tmpfs_nmknod(struct vop_nmknod_args *v)
196 {
197 	struct vnode *dvp = v->a_dvp;
198 	struct vnode **vpp = v->a_vpp;
199 	struct namecache *ncp = v->a_nch->ncp;
200 	struct vattr *vap = v->a_vap;
201 	struct ucred *cred = v->a_cred;
202 	int error;
203 
204 	if (vap->va_type != VBLK && vap->va_type != VCHR &&
205 	    vap->va_type != VFIFO) {
206 		return (EINVAL);
207 	}
208 
209 	error = tmpfs_alloc_file(dvp, vpp, vap, ncp, cred, NULL);
210 	if (error == 0) {
211 		cache_setunresolved(v->a_nch);
212 		cache_setvp(v->a_nch, *vpp);
213 		tmpfs_knote(dvp, NOTE_WRITE);
214 	}
215 	return error;
216 }
217 
218 /* --------------------------------------------------------------------- */
219 
220 static int
221 tmpfs_open(struct vop_open_args *v)
222 {
223 	struct vnode *vp = v->a_vp;
224 	int mode = v->a_mode;
225 	struct tmpfs_node *node;
226 	int error;
227 
228 	node = VP_TO_TMPFS_NODE(vp);
229 
230 #if 0
231 	/* The file is still active but all its names have been removed
232 	 * (e.g. by a "rmdir $(pwd)").  It cannot be opened any more as
233 	 * it is about to die. */
234 	if (node->tn_links < 1)
235 		return (ENOENT);
236 #endif
237 
238 	/* If the file is marked append-only, deny write requests. */
239 	if ((node->tn_flags & APPEND) &&
240 	    (mode & (FWRITE | O_APPEND)) == FWRITE) {
241 		error = EPERM;
242 	} else {
243 		error = (vop_stdopen(v));
244 	}
245 
246 	return (error);
247 }
248 
249 /* --------------------------------------------------------------------- */
250 
251 static int
252 tmpfs_close(struct vop_close_args *v)
253 {
254 	struct vnode *vp = v->a_vp;
255 	struct tmpfs_node *node;
256 	int error;
257 
258 	node = VP_TO_TMPFS_NODE(vp);
259 
260 	if (node->tn_links > 0) {
261 		/*
262 		 * Update node times.  No need to do it if the node has
263 		 * been deleted, because it will vanish after we return.
264 		 */
265 		tmpfs_update(vp);
266 	}
267 
268 	error = vop_stdclose(v);
269 
270 	return (error);
271 }
272 
273 /* --------------------------------------------------------------------- */
274 
275 int
276 tmpfs_access(struct vop_access_args *v)
277 {
278 	struct vnode *vp = v->a_vp;
279 	int error;
280 	struct tmpfs_node *node;
281 
282 	node = VP_TO_TMPFS_NODE(vp);
283 
284 	switch (vp->v_type) {
285 	case VDIR:
286 		/* FALLTHROUGH */
287 	case VLNK:
288 		/* FALLTHROUGH */
289 	case VREG:
290 		if ((v->a_mode & VWRITE) &&
291 	            (vp->v_mount->mnt_flag & MNT_RDONLY)) {
292 			error = EROFS;
293 			goto out;
294 		}
295 		break;
296 
297 	case VBLK:
298 		/* FALLTHROUGH */
299 	case VCHR:
300 		/* FALLTHROUGH */
301 	case VSOCK:
302 		/* FALLTHROUGH */
303 	case VFIFO:
304 		break;
305 
306 	default:
307 		error = EINVAL;
308 		goto out;
309 	}
310 
311 	if ((v->a_mode & VWRITE) && (node->tn_flags & IMMUTABLE)) {
312 		error = EPERM;
313 		goto out;
314 	}
315 
316 	error = vop_helper_access(v, node->tn_uid, node->tn_gid,
317 			          node->tn_mode, 0);
318 out:
319 	return error;
320 }
321 
322 /* --------------------------------------------------------------------- */
323 
324 int
325 tmpfs_getattr(struct vop_getattr_args *v)
326 {
327 	struct vnode *vp = v->a_vp;
328 	struct vattr *vap = v->a_vap;
329 	struct tmpfs_node *node;
330 
331 	node = VP_TO_TMPFS_NODE(vp);
332 
333 	tmpfs_update(vp);
334 
335 	TMPFS_NODE_LOCK_SH(node);
336 	vap->va_type = vp->v_type;
337 	vap->va_mode = node->tn_mode;
338 	vap->va_nlink = node->tn_links;
339 	vap->va_uid = node->tn_uid;
340 	vap->va_gid = node->tn_gid;
341 	vap->va_fsid = vp->v_mount->mnt_stat.f_fsid.val[0];
342 	vap->va_fileid = node->tn_id;
343 	vap->va_size = node->tn_size;
344 	vap->va_blocksize = PAGE_SIZE;
345 	vap->va_atime.tv_sec = node->tn_atime;
346 	vap->va_atime.tv_nsec = node->tn_atimensec;
347 	vap->va_mtime.tv_sec = node->tn_mtime;
348 	vap->va_mtime.tv_nsec = node->tn_mtimensec;
349 	vap->va_ctime.tv_sec = node->tn_ctime;
350 	vap->va_ctime.tv_nsec = node->tn_ctimensec;
351 	vap->va_gen = node->tn_gen;
352 	vap->va_flags = node->tn_flags;
353 	if (vp->v_type == VBLK || vp->v_type == VCHR) {
354 		vap->va_rmajor = umajor(node->tn_rdev);
355 		vap->va_rminor = uminor(node->tn_rdev);
356 	}
357 	vap->va_bytes = round_page(node->tn_size);
358 	vap->va_filerev = 0;
359 	TMPFS_NODE_UNLOCK(node);
360 
361 	return 0;
362 }
363 
364 /* --------------------------------------------------------------------- */
365 
366 int
367 tmpfs_setattr(struct vop_setattr_args *v)
368 {
369 	struct vnode *vp = v->a_vp;
370 	struct vattr *vap = v->a_vap;
371 	struct ucred *cred = v->a_cred;
372 	struct tmpfs_node *node = VP_TO_TMPFS_NODE(vp);
373 	int error = 0;
374 	int kflags = 0;
375 
376 	TMPFS_NODE_LOCK(node);
377 	if (error == 0 && (vap->va_flags != VNOVAL)) {
378 		error = tmpfs_chflags(vp, vap->va_flags, cred);
379 		kflags |= NOTE_ATTRIB;
380 	}
381 
382 	if (error == 0 && (vap->va_size != VNOVAL)) {
383 		if (vap->va_size > node->tn_size)
384 			kflags |= NOTE_WRITE | NOTE_EXTEND;
385 		else
386 			kflags |= NOTE_WRITE;
387 		error = tmpfs_chsize(vp, vap->va_size, cred);
388 	}
389 
390 	if (error == 0 && (vap->va_uid != (uid_t)VNOVAL ||
391 			   vap->va_gid != (gid_t)VNOVAL)) {
392 		error = tmpfs_chown(vp, vap->va_uid, vap->va_gid, cred);
393 		kflags |= NOTE_ATTRIB;
394 	}
395 
396 	if (error == 0 && (vap->va_mode != (mode_t)VNOVAL)) {
397 		error = tmpfs_chmod(vp, vap->va_mode, cred);
398 		kflags |= NOTE_ATTRIB;
399 	}
400 
401 	if (error == 0 && ((vap->va_atime.tv_sec != VNOVAL &&
402 	    vap->va_atime.tv_nsec != VNOVAL) ||
403 	    (vap->va_mtime.tv_sec != VNOVAL &&
404 	    vap->va_mtime.tv_nsec != VNOVAL) )) {
405 		error = tmpfs_chtimes(vp, &vap->va_atime, &vap->va_mtime,
406 				      vap->va_vaflags, cred);
407 		kflags |= NOTE_ATTRIB;
408 	}
409 
410 	/*
411 	 * Update the node times.  We give preference to the error codes
412 	 * generated by this function rather than the ones that may arise
413 	 * from tmpfs_update.
414 	 */
415 	tmpfs_update(vp);
416 	TMPFS_NODE_UNLOCK(node);
417 	tmpfs_knote(vp, kflags);
418 
419 	return (error);
420 }
421 
422 /* --------------------------------------------------------------------- */
423 
424 /*
425  * fsync is usually a NOP, but we must take action when unmounting or
426  * when recycling.
427  */
428 static int
429 tmpfs_fsync(struct vop_fsync_args *v)
430 {
431 	struct tmpfs_node *node;
432 	struct vnode *vp = v->a_vp;
433 
434 	node = VP_TO_TMPFS_NODE(vp);
435 
436 	tmpfs_update(vp);
437 	if (vp->v_type == VREG) {
438 		if (vp->v_flag & VRECLAIMED) {
439 			if (node->tn_links == 0)
440 				tmpfs_truncate(vp, 0);
441 			else
442 				vfsync(v->a_vp, v->a_waitfor, 1, NULL, NULL);
443 		}
444 	}
445 	return 0;
446 }
447 
448 /* --------------------------------------------------------------------- */
449 
450 static int
451 tmpfs_read (struct vop_read_args *ap)
452 {
453 	struct buf *bp;
454 	struct vnode *vp = ap->a_vp;
455 	struct uio *uio = ap->a_uio;
456 	struct tmpfs_node *node;
457 	off_t base_offset;
458 	size_t offset;
459 	size_t len;
460 	size_t resid;
461 	int error;
462 
463 	/*
464 	 * Check the basics
465 	 */
466 	if (uio->uio_offset < 0)
467 		return (EINVAL);
468 	if (vp->v_type != VREG)
469 		return (EINVAL);
470 
471 	/*
472 	 * Extract node, try to shortcut the operation through
473 	 * the VM page cache, allowing us to avoid buffer cache
474 	 * overheads.
475 	 */
476 	node = VP_TO_TMPFS_NODE(vp);
477         resid = uio->uio_resid;
478         error = vop_helper_read_shortcut(ap);
479         if (error)
480                 return error;
481         if (uio->uio_resid == 0) {
482 		if (resid)
483 			goto finished;
484 		return error;
485 	}
486 
487 	/*
488 	 * Fall-through to our normal read code.
489 	 */
490 	while (uio->uio_resid > 0 && uio->uio_offset < node->tn_size) {
491 		/*
492 		 * Use buffer cache I/O (via tmpfs_strategy)
493 		 */
494 		offset = (size_t)uio->uio_offset & TMPFS_BLKMASK64;
495 		base_offset = (off_t)uio->uio_offset - offset;
496 		bp = getcacheblk(vp, base_offset, TMPFS_BLKSIZE, 0);
497 		if (bp == NULL) {
498 			error = bread(vp, base_offset, TMPFS_BLKSIZE, &bp);
499 			if (error) {
500 				brelse(bp);
501 				kprintf("tmpfs_read bread error %d\n", error);
502 				break;
503 			}
504 
505 			/*
506 			 * tmpfs pretty much fiddles directly with the VM
507 			 * system, don't let it exhaust it or we won't play
508 			 * nice with other processes.
509 			 *
510 			 * Only do this if the VOP is coming from a normal
511 			 * read/write.  The VM system handles the case for
512 			 * UIO_NOCOPY.
513 			 */
514 			if (uio->uio_segflg != UIO_NOCOPY)
515 				vm_wait_nominal();
516 		}
517 		bp->b_flags |= B_CLUSTEROK;
518 
519 		/*
520 		 * Figure out how many bytes we can actually copy this loop.
521 		 */
522 		len = TMPFS_BLKSIZE - offset;
523 		if (len > uio->uio_resid)
524 			len = uio->uio_resid;
525 		if (len > node->tn_size - uio->uio_offset)
526 			len = (size_t)(node->tn_size - uio->uio_offset);
527 
528 		error = uiomovebp(bp, (char *)bp->b_data + offset, len, uio);
529 		bqrelse(bp);
530 		if (error) {
531 			kprintf("tmpfs_read uiomove error %d\n", error);
532 			break;
533 		}
534 	}
535 
536 finished:
537 	if ((node->tn_status & TMPFS_NODE_ACCESSED) == 0) {
538 		TMPFS_NODE_LOCK(node);
539 		node->tn_status |= TMPFS_NODE_ACCESSED;
540 		TMPFS_NODE_UNLOCK(node);
541 	}
542 	return (error);
543 }
544 
545 static int
546 tmpfs_write (struct vop_write_args *ap)
547 {
548 	struct buf *bp;
549 	struct vnode *vp = ap->a_vp;
550 	struct uio *uio = ap->a_uio;
551 	struct thread *td = uio->uio_td;
552 	struct tmpfs_node *node;
553 	boolean_t extended;
554 	off_t oldsize;
555 	int error;
556 	off_t base_offset;
557 	size_t offset;
558 	size_t len;
559 	struct rlimit limit;
560 	int trivial = 0;
561 	int kflags = 0;
562 	int seqcount;
563 
564 	error = 0;
565 	if (uio->uio_resid == 0) {
566 		return error;
567 	}
568 
569 	node = VP_TO_TMPFS_NODE(vp);
570 
571 	if (vp->v_type != VREG)
572 		return (EINVAL);
573 	seqcount = ap->a_ioflag >> 16;
574 
575 	TMPFS_NODE_LOCK(node);
576 
577 	oldsize = node->tn_size;
578 	if (ap->a_ioflag & IO_APPEND)
579 		uio->uio_offset = node->tn_size;
580 
581 	/*
582 	 * Check for illegal write offsets.
583 	 */
584 	if (uio->uio_offset + uio->uio_resid >
585 	  VFS_TO_TMPFS(vp->v_mount)->tm_maxfilesize) {
586 		error = EFBIG;
587 		goto done;
588 	}
589 
590 	/*
591 	 * NOTE: Ignore if UIO does not come from a user thread (e.g. VN).
592 	 */
593 	if (vp->v_type == VREG && td != NULL && td->td_lwp != NULL) {
594 		error = kern_getrlimit(RLIMIT_FSIZE, &limit);
595 		if (error)
596 			goto done;
597 		if (uio->uio_offset + uio->uio_resid > limit.rlim_cur) {
598 			ksignal(td->td_proc, SIGXFSZ);
599 			error = EFBIG;
600 			goto done;
601 		}
602 	}
603 
604 	/*
605 	 * Extend the file's size if necessary
606 	 */
607 	extended = ((uio->uio_offset + uio->uio_resid) > node->tn_size);
608 
609 	while (uio->uio_resid > 0) {
610 		/*
611 		 * Don't completely blow out running buffer I/O
612 		 * when being hit from the pageout daemon.
613 		 */
614 		if (uio->uio_segflg == UIO_NOCOPY &&
615 		    (ap->a_ioflag & IO_RECURSE) == 0) {
616 			bwillwrite(TMPFS_BLKSIZE);
617 		}
618 
619 		/*
620 		 * Use buffer cache I/O (via tmpfs_strategy)
621 		 */
622 		offset = (size_t)uio->uio_offset & TMPFS_BLKMASK64;
623 		base_offset = (off_t)uio->uio_offset - offset;
624 		len = TMPFS_BLKSIZE - offset;
625 		if (len > uio->uio_resid)
626 			len = uio->uio_resid;
627 
628 		if ((uio->uio_offset + len) > node->tn_size) {
629 			trivial = (uio->uio_offset <= node->tn_size);
630 			error = tmpfs_reg_resize(vp, uio->uio_offset + len,
631 						 trivial);
632 			if (error)
633 				break;
634 		}
635 
636 		/*
637 		 * Read to fill in any gaps.  Theoretically we could
638 		 * optimize this if the write covers the entire buffer
639 		 * and is not a UIO_NOCOPY write, however this can lead
640 		 * to a security violation exposing random kernel memory
641 		 * (whatever junk was in the backing VM pages before).
642 		 *
643 		 * So just use bread() to do the right thing.
644 		 */
645 		error = bread(vp, base_offset, TMPFS_BLKSIZE, &bp);
646 		error = uiomovebp(bp, (char *)bp->b_data + offset, len, uio);
647 		if (error) {
648 			kprintf("tmpfs_write uiomove error %d\n", error);
649 			brelse(bp);
650 			break;
651 		}
652 
653 		if (uio->uio_offset > node->tn_size) {
654 			node->tn_size = uio->uio_offset;
655 			kflags |= NOTE_EXTEND;
656 		}
657 		kflags |= NOTE_WRITE;
658 
659 		/*
660 		 * Always try to flush the page in the UIO_NOCOPY case.  This
661 		 * can come from the pageout daemon or during vnode eviction.
662 		 * It is not necessarily going to be marked IO_ASYNC/IO_SYNC.
663 		 *
664 		 * For the normal case we buwrite(), dirtying the underlying
665 		 * VM pages instead of dirtying the buffer and releasing the
666 		 * buffer as a clean buffer.  This allows tmpfs to use
667 		 * essentially all available memory to cache file data.
668 		 * If we used bdwrite() the buffer cache would wind up
669 		 * flushing the data to swap too quickly.
670 		 *
671 		 * But because tmpfs can seriously load the VM system we
672 		 * fall-back to using bdwrite() when free memory starts
673 		 * to get low.  This shifts the load away from the VM system
674 		 * and makes tmpfs act more like a normal filesystem with
675 		 * regards to disk activity.
676 		 *
677 		 * tmpfs pretty much fiddles directly with the VM
678 		 * system, don't let it exhaust it or we won't play
679 		 * nice with other processes.  Only do this if the
680 		 * VOP is coming from a normal read/write.  The VM system
681 		 * handles the case for UIO_NOCOPY.
682 		 */
683 		bp->b_flags |= B_CLUSTEROK;
684 		if (uio->uio_segflg == UIO_NOCOPY) {
685 			/*
686 			 * Flush from the pageout daemon, deal with
687 			 * potentially very heavy tmpfs write activity
688 			 * causing long stalls in the pageout daemon
689 			 * before pages get to free/cache.
690 			 *
691 			 * (a) Under severe pressure setting B_DIRECT will
692 			 *     cause a buffer release to try to free the
693 			 *     underlying pages.
694 			 *
695 			 * (b) Under modest memory pressure the B_RELBUF
696 			 *     alone is sufficient to get the pages moved
697 			 *     to the cache.  We could also force this by
698 			 *     setting B_NOTMETA but that might have other
699 			 *     unintended side-effects (e.g. setting
700 			 *     PG_NOTMETA on the VM page).
701 			 *
702 			 * Hopefully this will unblock the VM system more
703 			 * quickly under extreme tmpfs write load.
704 			 */
705 			if (vm_page_count_min(vm_page_free_hysteresis))
706 				bp->b_flags |= B_DIRECT;
707 			bp->b_flags |= B_AGE | B_RELBUF;
708 			bp->b_act_count = 0;	/* buffer->deactivate pgs */
709 			cluster_awrite(bp);
710 		} else if (vm_page_count_target()) {
711 			/*
712 			 * Normal (userland) write but we are low on memory,
713 			 * run the buffer the buffer cache.
714 			 */
715 			bp->b_act_count = 0;	/* buffer->deactivate pgs */
716 			bdwrite(bp);
717 		} else {
718 			/*
719 			 * Otherwise run the buffer directly through to the
720 			 * backing VM store.
721 			 */
722 			buwrite(bp);
723 			/*vm_wait_nominal();*/
724 		}
725 
726 		if (bp->b_error) {
727 			kprintf("tmpfs_write bwrite error %d\n", bp->b_error);
728 			break;
729 		}
730 	}
731 
732 	if (error) {
733 		if (extended) {
734 			(void)tmpfs_reg_resize(vp, oldsize, trivial);
735 			kflags &= ~NOTE_EXTEND;
736 		}
737 		goto done;
738 	}
739 
740 	/*
741 	 * Currently we don't set the mtime on files modified via mmap()
742 	 * because we can't tell the difference between those modifications
743 	 * and an attempt by the pageout daemon to flush tmpfs pages to
744 	 * swap.
745 	 *
746 	 * This is because in order to defer flushes as long as possible
747 	 * buwrite() works by marking the underlying VM pages dirty in
748 	 * order to be able to dispose of the buffer cache buffer without
749 	 * flushing it.
750 	 */
751 	if (uio->uio_segflg != UIO_NOCOPY)
752 		node->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED;
753 	if (extended)
754 		node->tn_status |= TMPFS_NODE_CHANGED;
755 
756 	if (node->tn_mode & (S_ISUID | S_ISGID)) {
757 		if (priv_check_cred(ap->a_cred, PRIV_VFS_RETAINSUGID, 0))
758 			node->tn_mode &= ~(S_ISUID | S_ISGID);
759 	}
760 done:
761 	TMPFS_NODE_UNLOCK(node);
762 	if (kflags)
763 		tmpfs_knote(vp, kflags);
764 
765 	return(error);
766 }
767 
768 static int
769 tmpfs_advlock (struct vop_advlock_args *ap)
770 {
771 	struct tmpfs_node *node;
772 	struct vnode *vp = ap->a_vp;
773 	int error;
774 
775 	node = VP_TO_TMPFS_NODE(vp);
776 	error = (lf_advlock(ap, &node->tn_advlock, node->tn_size));
777 
778 	return (error);
779 }
780 
781 /*
782  * The strategy function is typically only called when memory pressure
783  * forces the system to attempt to pageout pages.  It can also be called
784  * by [n]vtruncbuf() when a truncation cuts a page in half.  Normal write
785  * operations
786  */
787 static int
788 tmpfs_strategy(struct vop_strategy_args *ap)
789 {
790 	struct bio *bio = ap->a_bio;
791 	struct bio *nbio;
792 	struct buf *bp = bio->bio_buf;
793 	struct vnode *vp = ap->a_vp;
794 	struct tmpfs_node *node;
795 	vm_object_t uobj;
796 	vm_page_t m;
797 	int i;
798 
799 	if (vp->v_type != VREG) {
800 		bp->b_resid = bp->b_bcount;
801 		bp->b_flags |= B_ERROR | B_INVAL;
802 		bp->b_error = EINVAL;
803 		biodone(bio);
804 		return(0);
805 	}
806 
807 	node = VP_TO_TMPFS_NODE(vp);
808 
809 	uobj = node->tn_reg.tn_aobj;
810 
811 	/*
812 	 * Don't bother flushing to swap if there is no swap, just
813 	 * ensure that the pages are marked as needing a commit (still).
814 	 */
815 	if (bp->b_cmd == BUF_CMD_WRITE && vm_swap_size == 0) {
816 		for (i = 0; i < bp->b_xio.xio_npages; ++i) {
817 			m = bp->b_xio.xio_pages[i];
818 			vm_page_need_commit(m);
819 		}
820 		bp->b_resid = 0;
821 		bp->b_error = 0;
822 		biodone(bio);
823 	} else {
824 		nbio = push_bio(bio);
825 		nbio->bio_done = tmpfs_strategy_done;
826 		nbio->bio_offset = bio->bio_offset;
827 		swap_pager_strategy(uobj, nbio);
828 	}
829 	return 0;
830 }
831 
832 /*
833  * If we were unable to commit the pages to swap make sure they are marked
834  * as needing a commit (again).  If we were, clear the flag to allow the
835  * pages to be freed.
836  */
837 static void
838 tmpfs_strategy_done(struct bio *bio)
839 {
840 	struct buf *bp;
841 	vm_page_t m;
842 	int i;
843 
844 	bp = bio->bio_buf;
845 
846 	if (bp->b_flags & B_ERROR) {
847 		bp->b_flags &= ~B_ERROR;
848 		bp->b_error = 0;
849 		bp->b_resid = 0;
850 		for (i = 0; i < bp->b_xio.xio_npages; ++i) {
851 			m = bp->b_xio.xio_pages[i];
852 			vm_page_need_commit(m);
853 		}
854 	} else {
855 		for (i = 0; i < bp->b_xio.xio_npages; ++i) {
856 			m = bp->b_xio.xio_pages[i];
857 			vm_page_clear_commit(m);
858 		}
859 	}
860 	bio = pop_bio(bio);
861 	biodone(bio);
862 }
863 
864 static int
865 tmpfs_bmap(struct vop_bmap_args *ap)
866 {
867 	if (ap->a_doffsetp != NULL)
868 		*ap->a_doffsetp = ap->a_loffset;
869 	if (ap->a_runp != NULL)
870 		*ap->a_runp = 0;
871 	if (ap->a_runb != NULL)
872 		*ap->a_runb = 0;
873 
874 	return 0;
875 }
876 
877 /* --------------------------------------------------------------------- */
878 
879 static int
880 tmpfs_nremove(struct vop_nremove_args *v)
881 {
882 	struct vnode *dvp = v->a_dvp;
883 	struct namecache *ncp = v->a_nch->ncp;
884 	struct vnode *vp;
885 	int error;
886 	struct tmpfs_dirent *de;
887 	struct tmpfs_mount *tmp;
888 	struct tmpfs_node *dnode;
889 	struct tmpfs_node *node;
890 	struct mount *mp;
891 
892 	mp = dvp->v_mount;
893 
894 	/*
895 	 * We have to acquire the vp from v->a_nch because we will likely
896 	 * unresolve the namecache entry, and a vrele/vput is needed to
897 	 * trigger the tmpfs_inactive/tmpfs_reclaim sequence.
898 	 *
899 	 * We have to use vget to clear any inactive state on the vnode,
900 	 * otherwise the vnode may remain inactive and thus tmpfs_inactive
901 	 * will not get called when we release it.
902 	 */
903 	error = cache_vget(v->a_nch, v->a_cred, LK_SHARED, &vp);
904 	KKASSERT(vp->v_mount == dvp->v_mount);
905 	KKASSERT(error == 0);
906 	vn_unlock(vp);
907 
908 	if (vp->v_type == VDIR) {
909 		error = EISDIR;
910 		goto out2;
911 	}
912 
913 	dnode = VP_TO_TMPFS_DIR(dvp);
914 	node = VP_TO_TMPFS_NODE(vp);
915 	tmp = VFS_TO_TMPFS(vp->v_mount);
916 
917 	TMPFS_NODE_LOCK(dnode);
918 	de = tmpfs_dir_lookup(dnode, node, ncp);
919 	if (de == NULL) {
920 		error = ENOENT;
921 		goto out;
922 	}
923 
924 	/* Files marked as immutable or append-only cannot be deleted. */
925 	if ((node->tn_flags & (IMMUTABLE | APPEND | NOUNLINK)) ||
926 	    (dnode->tn_flags & APPEND)) {
927 		error = EPERM;
928 		goto out;
929 	}
930 
931 	/* Remove the entry from the directory; as it is a file, we do not
932 	 * have to change the number of hard links of the directory. */
933 	tmpfs_dir_detach(dnode, de);
934 
935 	/* Free the directory entry we just deleted.  Note that the node
936 	 * referred by it will not be removed until the vnode is really
937 	 * reclaimed. */
938 	tmpfs_free_dirent(tmp, de);
939 
940 	if (node->tn_links > 0) {
941 	        TMPFS_NODE_LOCK(node);
942 		node->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED | \
943 	                TMPFS_NODE_MODIFIED;
944 	        TMPFS_NODE_UNLOCK(node);
945 	}
946 
947 	cache_unlink(v->a_nch);
948 	tmpfs_knote(vp, NOTE_DELETE);
949 	error = 0;
950 
951 out:
952 	TMPFS_NODE_UNLOCK(dnode);
953 	if (error == 0)
954 		tmpfs_knote(dvp, NOTE_WRITE);
955 out2:
956 	vrele(vp);
957 
958 	return error;
959 }
960 
961 /* --------------------------------------------------------------------- */
962 
963 static int
964 tmpfs_nlink(struct vop_nlink_args *v)
965 {
966 	struct vnode *dvp = v->a_dvp;
967 	struct vnode *vp = v->a_vp;
968 	struct namecache *ncp = v->a_nch->ncp;
969 	struct tmpfs_dirent *de;
970 	struct tmpfs_node *node;
971 	struct tmpfs_node *dnode;
972 	struct mount *mp;
973 	int error;
974 
975 	mp = dvp->v_mount;
976 
977 	KKASSERT(dvp != vp); /* XXX When can this be false? */
978 
979 	node = VP_TO_TMPFS_NODE(vp);
980 	dnode = VP_TO_TMPFS_NODE(dvp);
981 	TMPFS_NODE_LOCK(dnode);
982 
983 	/* XXX: Why aren't the following two tests done by the caller? */
984 
985 	/* Hard links of directories are forbidden. */
986 	if (vp->v_type == VDIR) {
987 		error = EPERM;
988 		goto out;
989 	}
990 
991 	/* Cannot create cross-device links. */
992 	if (dvp->v_mount != vp->v_mount) {
993 		error = EXDEV;
994 		goto out;
995 	}
996 
997 	/* Ensure that we do not overflow the maximum number of links imposed
998 	 * by the system. */
999 	KKASSERT(node->tn_links <= LINK_MAX);
1000 	if (node->tn_links >= LINK_MAX) {
1001 		error = EMLINK;
1002 		goto out;
1003 	}
1004 
1005 	/* We cannot create links of files marked immutable or append-only. */
1006 	if (node->tn_flags & (IMMUTABLE | APPEND)) {
1007 		error = EPERM;
1008 		goto out;
1009 	}
1010 
1011 	/* Allocate a new directory entry to represent the node. */
1012 	error = tmpfs_alloc_dirent(VFS_TO_TMPFS(vp->v_mount), node,
1013 				   ncp->nc_name, ncp->nc_nlen, &de);
1014 	if (error != 0)
1015 		goto out;
1016 
1017 	/* Insert the new directory entry into the appropriate directory. */
1018 	tmpfs_dir_attach(dnode, de);
1019 
1020 	/* vp link count has changed, so update node times. */
1021 
1022 	TMPFS_NODE_LOCK(node);
1023 	node->tn_status |= TMPFS_NODE_CHANGED;
1024 	TMPFS_NODE_UNLOCK(node);
1025 	tmpfs_update(vp);
1026 
1027 	tmpfs_knote(vp, NOTE_LINK);
1028 	cache_setunresolved(v->a_nch);
1029 	cache_setvp(v->a_nch, vp);
1030 	error = 0;
1031 
1032 out:
1033 	TMPFS_NODE_UNLOCK(dnode);
1034 	if (error == 0)
1035 		tmpfs_knote(dvp, NOTE_WRITE);
1036 	return error;
1037 }
1038 
1039 /* --------------------------------------------------------------------- */
1040 
1041 static int
1042 tmpfs_nrename(struct vop_nrename_args *v)
1043 {
1044 	struct vnode *fdvp = v->a_fdvp;
1045 	struct namecache *fncp = v->a_fnch->ncp;
1046 	struct vnode *fvp = fncp->nc_vp;
1047 	struct vnode *tdvp = v->a_tdvp;
1048 	struct namecache *tncp = v->a_tnch->ncp;
1049 	struct vnode *tvp;
1050 	struct tmpfs_dirent *de, *tde;
1051 	struct tmpfs_mount *tmp;
1052 	struct tmpfs_node *fdnode;
1053 	struct tmpfs_node *fnode;
1054 	struct tmpfs_node *tnode;
1055 	struct tmpfs_node *tdnode;
1056 	struct mount *mp;
1057 	char *newname;
1058 	char *oldname;
1059 	int error;
1060 
1061 	mp = fdvp->v_mount;
1062 	KKASSERT(fdvp->v_mount == fvp->v_mount);
1063 
1064 	/*
1065 	 * Because tvp can get overwritten we have to vget it instead of
1066 	 * just vref or use it, otherwise it's VINACTIVE flag may not get
1067 	 * cleared and the node won't get destroyed.
1068 	 */
1069 	error = cache_vget(v->a_tnch, v->a_cred, LK_SHARED, &tvp);
1070 	if (error == 0) {
1071 		tnode = VP_TO_TMPFS_NODE(tvp);
1072 		vn_unlock(tvp);
1073 	} else {
1074 		tnode = NULL;
1075 	}
1076 
1077 	/* Disallow cross-device renames.
1078 	 * XXX Why isn't this done by the caller? */
1079 	if (fvp->v_mount != tdvp->v_mount ||
1080 	    (tvp != NULL && fvp->v_mount != tvp->v_mount)) {
1081 		error = EXDEV;
1082 		goto out;
1083 	}
1084 
1085 	tmp = VFS_TO_TMPFS(tdvp->v_mount);
1086 	tdnode = VP_TO_TMPFS_DIR(tdvp);
1087 
1088 	/* If source and target are the same file, there is nothing to do. */
1089 	if (fvp == tvp) {
1090 		error = 0;
1091 		goto out;
1092 	}
1093 
1094 	fdnode = VP_TO_TMPFS_DIR(fdvp);
1095 	fnode = VP_TO_TMPFS_NODE(fvp);
1096 	TMPFS_NODE_LOCK(fdnode);
1097 	de = tmpfs_dir_lookup(fdnode, fnode, fncp);
1098 	TMPFS_NODE_UNLOCK(fdnode);	/* XXX depend on namecache lock */
1099 
1100 	/* Avoid manipulating '.' and '..' entries. */
1101 	if (de == NULL) {
1102 		error = ENOENT;
1103 		goto out_locked;
1104 	}
1105 	KKASSERT(de->td_node == fnode);
1106 
1107 	/*
1108 	 * If replacing an entry in the target directory and that entry
1109 	 * is a directory, it must be empty.
1110 	 *
1111 	 * Kern_rename gurantees the destination to be a directory
1112 	 * if the source is one (it does?).
1113 	 */
1114 	if (tvp != NULL) {
1115 		KKASSERT(tnode != NULL);
1116 
1117 		if ((tnode->tn_flags & (NOUNLINK | IMMUTABLE | APPEND)) ||
1118 		    (tdnode->tn_flags & (APPEND | IMMUTABLE))) {
1119 			error = EPERM;
1120 			goto out_locked;
1121 		}
1122 
1123 		if (fnode->tn_type == VDIR && tnode->tn_type == VDIR) {
1124 			if (tnode->tn_size > 0) {
1125 				error = ENOTEMPTY;
1126 				goto out_locked;
1127 			}
1128 		} else if (fnode->tn_type == VDIR && tnode->tn_type != VDIR) {
1129 			error = ENOTDIR;
1130 			goto out_locked;
1131 		} else if (fnode->tn_type != VDIR && tnode->tn_type == VDIR) {
1132 			error = EISDIR;
1133 			goto out_locked;
1134 		} else {
1135 			KKASSERT(fnode->tn_type != VDIR &&
1136 				tnode->tn_type != VDIR);
1137 		}
1138 	}
1139 
1140 	if ((fnode->tn_flags & (NOUNLINK | IMMUTABLE | APPEND)) ||
1141 	    (fdnode->tn_flags & (APPEND | IMMUTABLE))) {
1142 		error = EPERM;
1143 		goto out_locked;
1144 	}
1145 
1146 	/*
1147 	 * Ensure that we have enough memory to hold the new name, if it
1148 	 * has to be changed.
1149 	 */
1150 	if (fncp->nc_nlen != tncp->nc_nlen ||
1151 	    bcmp(fncp->nc_name, tncp->nc_name, fncp->nc_nlen) != 0) {
1152 		newname = kmalloc(tncp->nc_nlen + 1, tmp->tm_name_zone,
1153 				  M_WAITOK | M_NULLOK);
1154 		if (newname == NULL) {
1155 			error = ENOSPC;
1156 			goto out_locked;
1157 		}
1158 		bcopy(tncp->nc_name, newname, tncp->nc_nlen);
1159 		newname[tncp->nc_nlen] = '\0';
1160 	} else {
1161 		newname = NULL;
1162 	}
1163 
1164 	/*
1165 	 * Unlink entry from source directory.  Note that the kernel has
1166 	 * already checked for illegal recursion cases (renaming a directory
1167 	 * into a subdirectory of itself).
1168 	 */
1169 	if (fdnode != tdnode) {
1170 		tmpfs_dir_detach(fdnode, de);
1171 	} else {
1172 		/* XXX depend on namecache lock */
1173 		TMPFS_NODE_LOCK(fdnode);
1174 		KKASSERT(de == tmpfs_dir_lookup(fdnode, fnode, fncp));
1175 		RB_REMOVE(tmpfs_dirtree, &fdnode->tn_dir.tn_dirtree, de);
1176 		RB_REMOVE(tmpfs_dirtree_cookie,
1177 			  &fdnode->tn_dir.tn_cookietree, de);
1178 		TMPFS_NODE_UNLOCK(fdnode);
1179 	}
1180 
1181 	/*
1182 	 * Handle any name change.  Swap with newname, we will
1183 	 * deallocate it at the end.
1184 	 */
1185 	if (newname != NULL) {
1186 #if 0
1187 		TMPFS_NODE_LOCK(fnode);
1188 		fnode->tn_status |= TMPFS_NODE_CHANGED;
1189 		TMPFS_NODE_UNLOCK(fnode);
1190 #endif
1191 		oldname = de->td_name;
1192 		de->td_name = newname;
1193 		de->td_namelen = (uint16_t)tncp->nc_nlen;
1194 		newname = oldname;
1195 	}
1196 
1197 	/*
1198 	 * If we are overwriting an entry, we have to remove the old one
1199 	 * from the target directory.
1200 	 */
1201 	if (tvp != NULL) {
1202 		/* Remove the old entry from the target directory. */
1203 		TMPFS_NODE_LOCK(tdnode);
1204 		tde = tmpfs_dir_lookup(tdnode, tnode, tncp);
1205 		tmpfs_dir_detach(tdnode, tde);
1206 		TMPFS_NODE_UNLOCK(tdnode);
1207 		tmpfs_knote(tdnode->tn_vnode, NOTE_DELETE);
1208 
1209 		/*
1210 		 * Free the directory entry we just deleted.  Note that the
1211 		 * node referred by it will not be removed until the vnode is
1212 		 * really reclaimed.
1213 		 */
1214 		tmpfs_free_dirent(VFS_TO_TMPFS(tvp->v_mount), tde);
1215 		/*cache_inval_vp(tvp, CINV_DESTROY);*/
1216 	}
1217 
1218 	/*
1219 	 * Link entry to target directory.  If the entry
1220 	 * represents a directory move the parent linkage
1221 	 * as well.
1222 	 */
1223 	if (fdnode != tdnode) {
1224 		if (de->td_node->tn_type == VDIR) {
1225 			TMPFS_VALIDATE_DIR(fnode);
1226 		}
1227 		tmpfs_dir_attach(tdnode, de);
1228 	} else {
1229 		TMPFS_NODE_LOCK(tdnode);
1230 		tdnode->tn_status |= TMPFS_NODE_MODIFIED;
1231 		RB_INSERT(tmpfs_dirtree, &tdnode->tn_dir.tn_dirtree, de);
1232 		RB_INSERT(tmpfs_dirtree_cookie,
1233 			  &tdnode->tn_dir.tn_cookietree, de);
1234 		TMPFS_NODE_UNLOCK(tdnode);
1235 	}
1236 
1237 	/*
1238 	 * Finish up
1239 	 */
1240 	if (newname) {
1241 		kfree(newname, tmp->tm_name_zone);
1242 		newname = NULL;
1243 	}
1244 	cache_rename(v->a_fnch, v->a_tnch);
1245 	tmpfs_knote(v->a_fdvp, NOTE_WRITE);
1246 	tmpfs_knote(v->a_tdvp, NOTE_WRITE);
1247 	if (fnode->tn_vnode)
1248 		tmpfs_knote(fnode->tn_vnode, NOTE_RENAME);
1249 	error = 0;
1250 
1251 out_locked:
1252 	;
1253 out:
1254 	if (tvp)
1255 		vrele(tvp);
1256 	return error;
1257 }
1258 
1259 /* --------------------------------------------------------------------- */
1260 
1261 static int
1262 tmpfs_nmkdir(struct vop_nmkdir_args *v)
1263 {
1264 	struct vnode *dvp = v->a_dvp;
1265 	struct vnode **vpp = v->a_vpp;
1266 	struct namecache *ncp = v->a_nch->ncp;
1267 	struct vattr *vap = v->a_vap;
1268 	struct ucred *cred = v->a_cred;
1269 	struct mount *mp;
1270 	int error;
1271 
1272 	mp = dvp->v_mount;
1273 
1274 	KKASSERT(vap->va_type == VDIR);
1275 
1276 	error = tmpfs_alloc_file(dvp, vpp, vap, ncp, cred, NULL);
1277 	if (error == 0) {
1278 		cache_setunresolved(v->a_nch);
1279 		cache_setvp(v->a_nch, *vpp);
1280 		tmpfs_knote(dvp, NOTE_WRITE | NOTE_LINK);
1281 	}
1282 	return error;
1283 }
1284 
1285 /* --------------------------------------------------------------------- */
1286 
1287 static int
1288 tmpfs_nrmdir(struct vop_nrmdir_args *v)
1289 {
1290 	struct vnode *dvp = v->a_dvp;
1291 	struct namecache *ncp = v->a_nch->ncp;
1292 	struct vnode *vp;
1293 	struct tmpfs_dirent *de;
1294 	struct tmpfs_mount *tmp;
1295 	struct tmpfs_node *dnode;
1296 	struct tmpfs_node *node;
1297 	struct mount *mp;
1298 	int error;
1299 
1300 	mp = dvp->v_mount;
1301 
1302 	/*
1303 	 * We have to acquire the vp from v->a_nch because we will likely
1304 	 * unresolve the namecache entry, and a vrele/vput is needed to
1305 	 * trigger the tmpfs_inactive/tmpfs_reclaim sequence.
1306 	 *
1307 	 * We have to use vget to clear any inactive state on the vnode,
1308 	 * otherwise the vnode may remain inactive and thus tmpfs_inactive
1309 	 * will not get called when we release it.
1310 	 */
1311 	error = cache_vget(v->a_nch, v->a_cred, LK_SHARED, &vp);
1312 	KKASSERT(error == 0);
1313 	vn_unlock(vp);
1314 
1315 	/*
1316 	 * Prevalidate so we don't hit an assertion later
1317 	 */
1318 	if (vp->v_type != VDIR) {
1319 		error = ENOTDIR;
1320 		goto out;
1321 	}
1322 
1323 	tmp = VFS_TO_TMPFS(dvp->v_mount);
1324 	dnode = VP_TO_TMPFS_DIR(dvp);
1325 	node = VP_TO_TMPFS_DIR(vp);
1326 
1327 	/*
1328 	 * Directories with more than two entries ('.' and '..') cannot
1329 	 * be removed.
1330 	 */
1331 	if (node->tn_size > 0) {
1332 		error = ENOTEMPTY;
1333 		goto out;
1334 	}
1335 
1336 	if ((dnode->tn_flags & APPEND)
1337 	    || (node->tn_flags & (NOUNLINK | IMMUTABLE | APPEND))) {
1338 		error = EPERM;
1339 		goto out;
1340 	}
1341 
1342 	/*
1343 	 * This invariant holds only if we are not trying to
1344 	 * remove "..".  We checked for that above so this is safe now.
1345 	 */
1346 	KKASSERT(node->tn_dir.tn_parent == dnode);
1347 
1348 	/*
1349 	 * Get the directory entry associated with node (vp).  This
1350 	 * was filled by tmpfs_lookup while looking up the entry.
1351 	 */
1352 	TMPFS_NODE_LOCK(dnode);
1353 	de = tmpfs_dir_lookup(dnode, node, ncp);
1354 	KKASSERT(TMPFS_DIRENT_MATCHES(de, ncp->nc_name, ncp->nc_nlen));
1355 
1356 	/* Check flags to see if we are allowed to remove the directory. */
1357 	if ((dnode->tn_flags & APPEND) ||
1358 	    node->tn_flags & (NOUNLINK | IMMUTABLE | APPEND)) {
1359 		error = EPERM;
1360 		TMPFS_NODE_UNLOCK(dnode);
1361 		goto out;
1362 	}
1363 
1364 	/* Detach the directory entry from the directory (dnode). */
1365 	tmpfs_dir_detach(dnode, de);
1366 	TMPFS_NODE_UNLOCK(dnode);
1367 
1368 	/* No vnode should be allocated for this entry from this point */
1369 	TMPFS_NODE_LOCK(dnode);
1370 	TMPFS_ASSERT_ELOCKED(dnode);
1371 	TMPFS_NODE_LOCK(node);
1372 	TMPFS_ASSERT_ELOCKED(node);
1373 
1374 	/*
1375 	 * Must set parent linkage to NULL (tested by ncreate to disallow
1376 	 * the creation of new files/dirs in a deleted directory)
1377 	 */
1378 	node->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED |
1379 			   TMPFS_NODE_MODIFIED;
1380 
1381 	dnode->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED |
1382 			    TMPFS_NODE_MODIFIED;
1383 
1384 	TMPFS_NODE_UNLOCK(node);
1385 	TMPFS_NODE_UNLOCK(dnode);
1386 
1387 	/* Free the directory entry we just deleted.  Note that the node
1388 	 * referred by it will not be removed until the vnode is really
1389 	 * reclaimed. */
1390 	tmpfs_free_dirent(tmp, de);
1391 
1392 	/* Release the deleted vnode (will destroy the node, notify
1393 	 * interested parties and clean it from the cache). */
1394 
1395 	TMPFS_NODE_LOCK(dnode);
1396 	dnode->tn_status |= TMPFS_NODE_CHANGED;
1397 	TMPFS_NODE_UNLOCK(dnode);
1398 	tmpfs_update(dvp);
1399 
1400 	cache_unlink(v->a_nch);
1401 	tmpfs_knote(dvp, NOTE_WRITE | NOTE_LINK);
1402 	error = 0;
1403 
1404 out:
1405 	vrele(vp);
1406 
1407 	return error;
1408 }
1409 
1410 /* --------------------------------------------------------------------- */
1411 
1412 static int
1413 tmpfs_nsymlink(struct vop_nsymlink_args *v)
1414 {
1415 	struct vnode *dvp = v->a_dvp;
1416 	struct vnode **vpp = v->a_vpp;
1417 	struct namecache *ncp = v->a_nch->ncp;
1418 	struct vattr *vap = v->a_vap;
1419 	struct ucred *cred = v->a_cred;
1420 	char *target = v->a_target;
1421 	int error;
1422 
1423 	vap->va_type = VLNK;
1424 	error = tmpfs_alloc_file(dvp, vpp, vap, ncp, cred, target);
1425 	if (error == 0) {
1426 		tmpfs_knote(*vpp, NOTE_WRITE);
1427 		cache_setunresolved(v->a_nch);
1428 		cache_setvp(v->a_nch, *vpp);
1429 	}
1430 	return error;
1431 }
1432 
1433 /* --------------------------------------------------------------------- */
1434 
1435 static int
1436 tmpfs_readdir(struct vop_readdir_args *v)
1437 {
1438 	struct vnode *vp = v->a_vp;
1439 	struct uio *uio = v->a_uio;
1440 	int *eofflag = v->a_eofflag;
1441 	off_t **cookies = v->a_cookies;
1442 	int *ncookies = v->a_ncookies;
1443 	struct tmpfs_mount *tmp;
1444 	int error;
1445 	off_t startoff;
1446 	off_t cnt = 0;
1447 	struct tmpfs_node *node;
1448 
1449 	/* This operation only makes sense on directory nodes. */
1450 	if (vp->v_type != VDIR) {
1451 		return ENOTDIR;
1452 	}
1453 
1454 	tmp = VFS_TO_TMPFS(vp->v_mount);
1455 	node = VP_TO_TMPFS_DIR(vp);
1456 	startoff = uio->uio_offset;
1457 
1458 	if (uio->uio_offset == TMPFS_DIRCOOKIE_DOT) {
1459 		error = tmpfs_dir_getdotdent(node, uio);
1460 		if (error != 0) {
1461 			TMPFS_NODE_LOCK_SH(node);
1462 			goto outok;
1463 		}
1464 		cnt++;
1465 	}
1466 
1467 	if (uio->uio_offset == TMPFS_DIRCOOKIE_DOTDOT) {
1468 		/* may lock parent, cannot hold node lock */
1469 		error = tmpfs_dir_getdotdotdent(tmp, node, uio);
1470 		if (error != 0) {
1471 			TMPFS_NODE_LOCK_SH(node);
1472 			goto outok;
1473 		}
1474 		cnt++;
1475 	}
1476 
1477 	TMPFS_NODE_LOCK_SH(node);
1478 	error = tmpfs_dir_getdents(node, uio, &cnt);
1479 
1480 outok:
1481 	KKASSERT(error >= -1);
1482 
1483 	if (error == -1)
1484 		error = 0;
1485 
1486 	if (eofflag != NULL)
1487 		*eofflag =
1488 		    (error == 0 && uio->uio_offset == TMPFS_DIRCOOKIE_EOF);
1489 
1490 	/* Update NFS-related variables. */
1491 	if (error == 0 && cookies != NULL && ncookies != NULL) {
1492 		off_t i;
1493 		off_t off = startoff;
1494 		struct tmpfs_dirent *de = NULL;
1495 
1496 		*ncookies = cnt;
1497 		*cookies = kmalloc(cnt * sizeof(off_t), M_TEMP, M_WAITOK);
1498 
1499 		for (i = 0; i < cnt; i++) {
1500 			KKASSERT(off != TMPFS_DIRCOOKIE_EOF);
1501 			if (off == TMPFS_DIRCOOKIE_DOT) {
1502 				off = TMPFS_DIRCOOKIE_DOTDOT;
1503 			} else {
1504 				if (off == TMPFS_DIRCOOKIE_DOTDOT) {
1505 					de = RB_MIN(tmpfs_dirtree_cookie,
1506 						&node->tn_dir.tn_cookietree);
1507 				} else if (de != NULL) {
1508 					de = RB_NEXT(tmpfs_dirtree_cookie,
1509 					       &node->tn_dir.tn_cookietree, de);
1510 				} else {
1511 					de = tmpfs_dir_lookupbycookie(node,
1512 								      off);
1513 					KKASSERT(de != NULL);
1514 					de = RB_NEXT(tmpfs_dirtree_cookie,
1515 					       &node->tn_dir.tn_cookietree, de);
1516 				}
1517 				if (de == NULL)
1518 					off = TMPFS_DIRCOOKIE_EOF;
1519 				else
1520 					off = tmpfs_dircookie(de);
1521 			}
1522 			(*cookies)[i] = off;
1523 		}
1524 		KKASSERT(uio->uio_offset == off);
1525 	}
1526 	TMPFS_NODE_UNLOCK(node);
1527 
1528 	if ((node->tn_status & TMPFS_NODE_ACCESSED) == 0) {
1529 		TMPFS_NODE_LOCK(node);
1530 		node->tn_status |= TMPFS_NODE_ACCESSED;
1531 		TMPFS_NODE_UNLOCK(node);
1532 	}
1533 	return error;
1534 }
1535 
1536 /* --------------------------------------------------------------------- */
1537 
1538 static int
1539 tmpfs_readlink(struct vop_readlink_args *v)
1540 {
1541 	struct vnode *vp = v->a_vp;
1542 	struct uio *uio = v->a_uio;
1543 	int error;
1544 	struct tmpfs_node *node;
1545 
1546 	KKASSERT(uio->uio_offset == 0);
1547 	KKASSERT(vp->v_type == VLNK);
1548 
1549 	node = VP_TO_TMPFS_NODE(vp);
1550 	TMPFS_NODE_LOCK_SH(node);
1551 	error = uiomove(node->tn_link,
1552 			MIN(node->tn_size, uio->uio_resid), uio);
1553 	TMPFS_NODE_UNLOCK(node);
1554 	if ((node->tn_status & TMPFS_NODE_ACCESSED) == 0) {
1555 		TMPFS_NODE_LOCK(node);
1556 		node->tn_status |= TMPFS_NODE_ACCESSED;
1557 		TMPFS_NODE_UNLOCK(node);
1558 	}
1559 	return error;
1560 }
1561 
1562 /* --------------------------------------------------------------------- */
1563 
1564 static int
1565 tmpfs_inactive(struct vop_inactive_args *v)
1566 {
1567 	struct vnode *vp = v->a_vp;
1568 	struct tmpfs_node *node;
1569 	struct mount *mp;
1570 
1571 	mp = vp->v_mount;
1572 	lwkt_gettoken(&mp->mnt_token);
1573 	node = VP_TO_TMPFS_NODE(vp);
1574 
1575 	/*
1576 	 * Degenerate case
1577 	 */
1578 	if (node == NULL) {
1579 		vrecycle(vp);
1580 		lwkt_reltoken(&mp->mnt_token);
1581 		return(0);
1582 	}
1583 
1584 	/*
1585 	 * Get rid of unreferenced deleted vnodes sooner rather than
1586 	 * later so the data memory can be recovered immediately.
1587 	 *
1588 	 * We must truncate the vnode to prevent the normal reclamation
1589 	 * path from flushing the data for the removed file to disk.
1590 	 */
1591 	TMPFS_NODE_LOCK(node);
1592 	if ((node->tn_vpstate & TMPFS_VNODE_ALLOCATING) == 0 &&
1593 	    node->tn_links == 0)
1594 	{
1595 		node->tn_vpstate = TMPFS_VNODE_DOOMED;
1596 		TMPFS_NODE_UNLOCK(node);
1597 		if (node->tn_type == VREG)
1598 			tmpfs_truncate(vp, 0);
1599 		vrecycle(vp);
1600 	} else {
1601 		TMPFS_NODE_UNLOCK(node);
1602 	}
1603 	lwkt_reltoken(&mp->mnt_token);
1604 
1605 	return 0;
1606 }
1607 
1608 /* --------------------------------------------------------------------- */
1609 
1610 int
1611 tmpfs_reclaim(struct vop_reclaim_args *v)
1612 {
1613 	struct vnode *vp = v->a_vp;
1614 	struct tmpfs_mount *tmp;
1615 	struct tmpfs_node *node;
1616 	struct mount *mp;
1617 
1618 	mp = vp->v_mount;
1619 	lwkt_gettoken(&mp->mnt_token);
1620 
1621 	node = VP_TO_TMPFS_NODE(vp);
1622 	tmp = VFS_TO_TMPFS(vp->v_mount);
1623 	KKASSERT(mp == tmp->tm_mount);
1624 
1625 	tmpfs_free_vp(vp);
1626 
1627 	/*
1628 	 * If the node referenced by this vnode was deleted by the
1629 	 * user, we must free its associated data structures now that
1630 	 * the vnode is being reclaimed.
1631 	 *
1632 	 * Directories have an extra link ref.
1633 	 */
1634 	TMPFS_NODE_LOCK(node);
1635 	if ((node->tn_vpstate & TMPFS_VNODE_ALLOCATING) == 0 &&
1636 	    node->tn_links == 0) {
1637 		node->tn_vpstate = TMPFS_VNODE_DOOMED;
1638 		tmpfs_free_node(tmp, node);
1639 		/* eats the lock */
1640 	} else {
1641 		TMPFS_NODE_UNLOCK(node);
1642 	}
1643 	lwkt_reltoken(&mp->mnt_token);
1644 
1645 	KKASSERT(vp->v_data == NULL);
1646 	return 0;
1647 }
1648 
1649 /* --------------------------------------------------------------------- */
1650 
1651 static int
1652 tmpfs_mountctl(struct vop_mountctl_args *ap)
1653 {
1654 	struct tmpfs_mount *tmp;
1655 	struct mount *mp;
1656 	int rc;
1657 
1658 	mp = ap->a_head.a_ops->head.vv_mount;
1659 	lwkt_gettoken(&mp->mnt_token);
1660 
1661 	switch (ap->a_op) {
1662 	case (MOUNTCTL_SET_EXPORT):
1663 		tmp = (struct tmpfs_mount *) mp->mnt_data;
1664 
1665 		if (ap->a_ctllen != sizeof(struct export_args))
1666 			rc = (EINVAL);
1667 		else
1668 			rc = vfs_export(mp, &tmp->tm_export,
1669 					(const struct export_args *) ap->a_ctl);
1670 		break;
1671 	default:
1672 		rc = vop_stdmountctl(ap);
1673 		break;
1674 	}
1675 
1676 	lwkt_reltoken(&mp->mnt_token);
1677 	return (rc);
1678 }
1679 
1680 /* --------------------------------------------------------------------- */
1681 
1682 static int
1683 tmpfs_print(struct vop_print_args *v)
1684 {
1685 	struct vnode *vp = v->a_vp;
1686 
1687 	struct tmpfs_node *node;
1688 
1689 	node = VP_TO_TMPFS_NODE(vp);
1690 
1691 	kprintf("tag VT_TMPFS, tmpfs_node %p, flags 0x%x, links %d\n",
1692 	    node, node->tn_flags, node->tn_links);
1693 	kprintf("\tmode 0%o, owner %d, group %d, size %ju, status 0x%x\n",
1694 	    node->tn_mode, node->tn_uid, node->tn_gid,
1695 	    (uintmax_t)node->tn_size, node->tn_status);
1696 
1697 	if (vp->v_type == VFIFO)
1698 		fifo_printinfo(vp);
1699 
1700 	kprintf("\n");
1701 
1702 	return 0;
1703 }
1704 
1705 /* --------------------------------------------------------------------- */
1706 
1707 static int
1708 tmpfs_pathconf(struct vop_pathconf_args *v)
1709 {
1710 	int name = v->a_name;
1711 	register_t *retval = v->a_retval;
1712 
1713 	int error;
1714 
1715 	error = 0;
1716 
1717 	switch (name) {
1718 	case _PC_LINK_MAX:
1719 		*retval = LINK_MAX;
1720 		break;
1721 
1722 	case _PC_NAME_MAX:
1723 		*retval = NAME_MAX;
1724 		break;
1725 
1726 	case _PC_PATH_MAX:
1727 		*retval = PATH_MAX;
1728 		break;
1729 
1730 	case _PC_PIPE_BUF:
1731 		*retval = PIPE_BUF;
1732 		break;
1733 
1734 	case _PC_CHOWN_RESTRICTED:
1735 		*retval = 1;
1736 		break;
1737 
1738 	case _PC_NO_TRUNC:
1739 		*retval = 1;
1740 		break;
1741 
1742 	case _PC_SYNC_IO:
1743 		*retval = 1;
1744 		break;
1745 
1746 	case _PC_FILESIZEBITS:
1747 		*retval = 0; /* XXX Don't know which value should I return. */
1748 		break;
1749 
1750 	default:
1751 		error = EINVAL;
1752 	}
1753 
1754 	return error;
1755 }
1756 
1757 /************************************************************************
1758  *                          KQFILTER OPS                                *
1759  ************************************************************************/
1760 
1761 static void filt_tmpfsdetach(struct knote *kn);
1762 static int filt_tmpfsread(struct knote *kn, long hint);
1763 static int filt_tmpfswrite(struct knote *kn, long hint);
1764 static int filt_tmpfsvnode(struct knote *kn, long hint);
1765 
1766 static struct filterops tmpfsread_filtops =
1767 	{ FILTEROP_ISFD | FILTEROP_MPSAFE,
1768 	  NULL, filt_tmpfsdetach, filt_tmpfsread };
1769 static struct filterops tmpfswrite_filtops =
1770 	{ FILTEROP_ISFD | FILTEROP_MPSAFE,
1771 	  NULL, filt_tmpfsdetach, filt_tmpfswrite };
1772 static struct filterops tmpfsvnode_filtops =
1773 	{ FILTEROP_ISFD | FILTEROP_MPSAFE,
1774 	  NULL, filt_tmpfsdetach, filt_tmpfsvnode };
1775 
1776 static int
1777 tmpfs_kqfilter (struct vop_kqfilter_args *ap)
1778 {
1779 	struct vnode *vp = ap->a_vp;
1780 	struct knote *kn = ap->a_kn;
1781 
1782 	switch (kn->kn_filter) {
1783 	case EVFILT_READ:
1784 		kn->kn_fop = &tmpfsread_filtops;
1785 		break;
1786 	case EVFILT_WRITE:
1787 		kn->kn_fop = &tmpfswrite_filtops;
1788 		break;
1789 	case EVFILT_VNODE:
1790 		kn->kn_fop = &tmpfsvnode_filtops;
1791 		break;
1792 	default:
1793 		return (EOPNOTSUPP);
1794 	}
1795 
1796 	kn->kn_hook = (caddr_t)vp;
1797 
1798 	knote_insert(&vp->v_pollinfo.vpi_kqinfo.ki_note, kn);
1799 
1800 	return(0);
1801 }
1802 
1803 static void
1804 filt_tmpfsdetach(struct knote *kn)
1805 {
1806 	struct vnode *vp = (void *)kn->kn_hook;
1807 
1808 	knote_remove(&vp->v_pollinfo.vpi_kqinfo.ki_note, kn);
1809 }
1810 
1811 static int
1812 filt_tmpfsread(struct knote *kn, long hint)
1813 {
1814 	struct vnode *vp = (void *)kn->kn_hook;
1815 	struct tmpfs_node *node = VP_TO_TMPFS_NODE(vp);
1816 	off_t off;
1817 
1818 	if (hint == NOTE_REVOKE) {
1819 		kn->kn_flags |= (EV_EOF | EV_NODATA | EV_ONESHOT);
1820 		return(1);
1821 	}
1822 
1823 	/*
1824 	 * Interlock against MP races when performing this function.
1825 	 */
1826 	TMPFS_NODE_LOCK_SH(node);
1827 	off = node->tn_size - kn->kn_fp->f_offset;
1828 	kn->kn_data = (off < INTPTR_MAX) ? off : INTPTR_MAX;
1829 	if (kn->kn_sfflags & NOTE_OLDAPI) {
1830 		TMPFS_NODE_UNLOCK(node);
1831 		return(1);
1832 	}
1833 	if (kn->kn_data == 0) {
1834 		kn->kn_data = (off < INTPTR_MAX) ? off : INTPTR_MAX;
1835 	}
1836 	TMPFS_NODE_UNLOCK(node);
1837 	return (kn->kn_data != 0);
1838 }
1839 
1840 static int
1841 filt_tmpfswrite(struct knote *kn, long hint)
1842 {
1843 	if (hint == NOTE_REVOKE)
1844 		kn->kn_flags |= (EV_EOF | EV_NODATA | EV_ONESHOT);
1845 	kn->kn_data = 0;
1846 	return (1);
1847 }
1848 
1849 static int
1850 filt_tmpfsvnode(struct knote *kn, long hint)
1851 {
1852 	if (kn->kn_sfflags & hint)
1853 		kn->kn_fflags |= hint;
1854 	if (hint == NOTE_REVOKE) {
1855 		kn->kn_flags |= (EV_EOF | EV_NODATA);
1856 		return (1);
1857 	}
1858 	return (kn->kn_fflags != 0);
1859 }
1860 
1861 
1862 /* --------------------------------------------------------------------- */
1863 
1864 /*
1865  * vnode operations vector used for files stored in a tmpfs file system.
1866  */
1867 struct vop_ops tmpfs_vnode_vops = {
1868 	.vop_default =			vop_defaultop,
1869 	.vop_getpages = 		vop_stdgetpages,
1870 	.vop_putpages = 		vop_stdputpages,
1871 	.vop_ncreate =			tmpfs_ncreate,
1872 	.vop_nresolve =			tmpfs_nresolve,
1873 	.vop_nlookupdotdot =		tmpfs_nlookupdotdot,
1874 	.vop_nmknod =			tmpfs_nmknod,
1875 	.vop_open =			tmpfs_open,
1876 	.vop_close =			tmpfs_close,
1877 	.vop_access =			tmpfs_access,
1878 	.vop_getattr =			tmpfs_getattr,
1879 	.vop_setattr =			tmpfs_setattr,
1880 	.vop_read =			tmpfs_read,
1881 	.vop_write =			tmpfs_write,
1882 	.vop_fsync =			tmpfs_fsync,
1883 	.vop_mountctl =			tmpfs_mountctl,
1884 	.vop_nremove =			tmpfs_nremove,
1885 	.vop_nlink =			tmpfs_nlink,
1886 	.vop_nrename =			tmpfs_nrename,
1887 	.vop_nmkdir =			tmpfs_nmkdir,
1888 	.vop_nrmdir =			tmpfs_nrmdir,
1889 	.vop_nsymlink =			tmpfs_nsymlink,
1890 	.vop_readdir =			tmpfs_readdir,
1891 	.vop_readlink =			tmpfs_readlink,
1892 	.vop_inactive =			tmpfs_inactive,
1893 	.vop_reclaim =			tmpfs_reclaim,
1894 	.vop_print =			tmpfs_print,
1895 	.vop_pathconf =			tmpfs_pathconf,
1896 	.vop_bmap =			tmpfs_bmap,
1897 	.vop_strategy =			tmpfs_strategy,
1898 	.vop_advlock =			tmpfs_advlock,
1899 	.vop_kqfilter =			tmpfs_kqfilter
1900 };
1901