xref: /dflybsd-src/sys/vfs/tmpfs/tmpfs_vnops.c (revision 215b902242b386e5a01c72d8245df7535bed0bd0)
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 == 0)
109 			KKASSERT(vp);
110 	}
111 	TMPFS_NODE_UNLOCK(dnode);
112 
113 	if ((dnode->tn_status & TMPFS_NODE_ACCESSED) == 0) {
114 		TMPFS_NODE_LOCK(dnode);
115 		dnode->tn_status |= TMPFS_NODE_ACCESSED;
116 		TMPFS_NODE_UNLOCK(dnode);
117 	}
118 
119 	/*
120 	 * Store the result of this lookup in the cache.  Avoid this if the
121 	 * request was for creation, as it does not improve timings on
122 	 * emprical tests.
123 	 */
124 	if (vp) {
125 		vn_unlock(vp);
126 		cache_setvp(v->a_nch, vp);
127 		vrele(vp);
128 	} else if (error == ENOENT) {
129 		cache_setvp(v->a_nch, NULL);
130 	}
131 	return (error);
132 }
133 
134 static int
135 tmpfs_nlookupdotdot(struct vop_nlookupdotdot_args *v)
136 {
137 	struct vnode *dvp = v->a_dvp;
138 	struct vnode **vpp = v->a_vpp;
139 	struct tmpfs_node *dnode = VP_TO_TMPFS_NODE(dvp);
140 	struct ucred *cred = v->a_cred;
141 	struct mount *mp;
142 	int error;
143 
144 	*vpp = NULL;
145 
146 	mp = dvp->v_mount;
147 
148 	/* Check accessibility of requested node as a first step. */
149 	error = VOP_ACCESS(dvp, VEXEC, cred);
150 	if (error != 0)
151 		return error;
152 
153 	if (dnode->tn_dir.tn_parent != NULL) {
154 		/* Allocate a new vnode on the matching entry. */
155 		error = tmpfs_alloc_vp(dvp->v_mount, dnode->tn_dir.tn_parent,
156 				       LK_EXCLUSIVE | LK_RETRY, vpp);
157 
158 		if (*vpp)
159 			vn_unlock(*vpp);
160 	}
161 	return (*vpp == NULL) ? ENOENT : 0;
162 }
163 
164 /* --------------------------------------------------------------------- */
165 
166 static int
167 tmpfs_ncreate(struct vop_ncreate_args *v)
168 {
169 	struct vnode *dvp = v->a_dvp;
170 	struct vnode **vpp = v->a_vpp;
171 	struct namecache *ncp = v->a_nch->ncp;
172 	struct vattr *vap = v->a_vap;
173 	struct ucred *cred = v->a_cred;
174 	struct mount *mp;
175 	int error;
176 
177 	mp = dvp->v_mount;
178 
179 	KKASSERT(vap->va_type == VREG || vap->va_type == VSOCK);
180 
181 	error = tmpfs_alloc_file(dvp, vpp, vap, ncp, cred, NULL);
182 	if (error == 0) {
183 		cache_setunresolved(v->a_nch);
184 		cache_setvp(v->a_nch, *vpp);
185 		tmpfs_knote(dvp, NOTE_WRITE);
186 	}
187 	return (error);
188 }
189 /* --------------------------------------------------------------------- */
190 
191 static int
192 tmpfs_nmknod(struct vop_nmknod_args *v)
193 {
194 	struct vnode *dvp = v->a_dvp;
195 	struct vnode **vpp = v->a_vpp;
196 	struct namecache *ncp = v->a_nch->ncp;
197 	struct vattr *vap = v->a_vap;
198 	struct ucred *cred = v->a_cred;
199 	int error;
200 
201 	if (vap->va_type != VBLK && vap->va_type != VCHR &&
202 	    vap->va_type != VFIFO) {
203 		return (EINVAL);
204 	}
205 
206 	error = tmpfs_alloc_file(dvp, vpp, vap, ncp, cred, NULL);
207 	if (error == 0) {
208 		cache_setunresolved(v->a_nch);
209 		cache_setvp(v->a_nch, *vpp);
210 		tmpfs_knote(dvp, NOTE_WRITE);
211 	}
212 	return error;
213 }
214 
215 /* --------------------------------------------------------------------- */
216 
217 static int
218 tmpfs_open(struct vop_open_args *v)
219 {
220 	struct vnode *vp = v->a_vp;
221 	int mode = v->a_mode;
222 	struct tmpfs_node *node;
223 	int error;
224 
225 	node = VP_TO_TMPFS_NODE(vp);
226 
227 #if 0
228 	/* The file is still active but all its names have been removed
229 	 * (e.g. by a "rmdir $(pwd)").  It cannot be opened any more as
230 	 * it is about to die. */
231 	if (node->tn_links < 1)
232 		return (ENOENT);
233 #endif
234 
235 	/* If the file is marked append-only, deny write requests. */
236 	if ((node->tn_flags & APPEND) &&
237 	    (mode & (FWRITE | O_APPEND)) == FWRITE) {
238 		error = EPERM;
239 	} else {
240 		error = (vop_stdopen(v));
241 	}
242 
243 	return (error);
244 }
245 
246 /* --------------------------------------------------------------------- */
247 
248 static int
249 tmpfs_close(struct vop_close_args *v)
250 {
251 	struct vnode *vp = v->a_vp;
252 	struct tmpfs_node *node;
253 	int error;
254 
255 	node = VP_TO_TMPFS_NODE(vp);
256 
257 	if (node->tn_links > 0) {
258 		/*
259 		 * Update node times.  No need to do it if the node has
260 		 * been deleted, because it will vanish after we return.
261 		 */
262 		tmpfs_update(vp);
263 	}
264 
265 	error = vop_stdclose(v);
266 
267 	return (error);
268 }
269 
270 /* --------------------------------------------------------------------- */
271 
272 int
273 tmpfs_access(struct vop_access_args *v)
274 {
275 	struct vnode *vp = v->a_vp;
276 	int error;
277 	struct tmpfs_node *node;
278 
279 	node = VP_TO_TMPFS_NODE(vp);
280 
281 	switch (vp->v_type) {
282 	case VDIR:
283 		/* FALLTHROUGH */
284 	case VLNK:
285 		/* FALLTHROUGH */
286 	case VREG:
287 		if ((v->a_mode & VWRITE) &&
288 	            (vp->v_mount->mnt_flag & MNT_RDONLY)) {
289 			error = EROFS;
290 			goto out;
291 		}
292 		break;
293 
294 	case VBLK:
295 		/* FALLTHROUGH */
296 	case VCHR:
297 		/* FALLTHROUGH */
298 	case VSOCK:
299 		/* FALLTHROUGH */
300 	case VFIFO:
301 		break;
302 
303 	default:
304 		error = EINVAL;
305 		goto out;
306 	}
307 
308 	if ((v->a_mode & VWRITE) && (node->tn_flags & IMMUTABLE)) {
309 		error = EPERM;
310 		goto out;
311 	}
312 
313 	error = vop_helper_access(v, node->tn_uid, node->tn_gid,
314 			          node->tn_mode, 0);
315 out:
316 	return error;
317 }
318 
319 /* --------------------------------------------------------------------- */
320 
321 int
322 tmpfs_getattr(struct vop_getattr_args *v)
323 {
324 	struct vnode *vp = v->a_vp;
325 	struct vattr *vap = v->a_vap;
326 	struct tmpfs_node *node;
327 
328 	node = VP_TO_TMPFS_NODE(vp);
329 
330 	tmpfs_update(vp);
331 
332 	TMPFS_NODE_LOCK_SH(node);
333 	vap->va_type = vp->v_type;
334 	vap->va_mode = node->tn_mode;
335 	vap->va_nlink = node->tn_links;
336 	vap->va_uid = node->tn_uid;
337 	vap->va_gid = node->tn_gid;
338 	vap->va_fsid = vp->v_mount->mnt_stat.f_fsid.val[0];
339 	vap->va_fileid = node->tn_id;
340 	vap->va_size = node->tn_size;
341 	vap->va_blocksize = PAGE_SIZE;
342 	vap->va_atime.tv_sec = node->tn_atime;
343 	vap->va_atime.tv_nsec = node->tn_atimensec;
344 	vap->va_mtime.tv_sec = node->tn_mtime;
345 	vap->va_mtime.tv_nsec = node->tn_mtimensec;
346 	vap->va_ctime.tv_sec = node->tn_ctime;
347 	vap->va_ctime.tv_nsec = node->tn_ctimensec;
348 	vap->va_gen = node->tn_gen;
349 	vap->va_flags = node->tn_flags;
350 	if (vp->v_type == VBLK || vp->v_type == VCHR) {
351 		vap->va_rmajor = umajor(node->tn_rdev);
352 		vap->va_rminor = uminor(node->tn_rdev);
353 	}
354 	vap->va_bytes = round_page(node->tn_size);
355 	vap->va_filerev = 0;
356 	TMPFS_NODE_UNLOCK(node);
357 
358 	return 0;
359 }
360 
361 /* --------------------------------------------------------------------- */
362 
363 int
364 tmpfs_setattr(struct vop_setattr_args *v)
365 {
366 	struct vnode *vp = v->a_vp;
367 	struct vattr *vap = v->a_vap;
368 	struct ucred *cred = v->a_cred;
369 	struct tmpfs_node *node = VP_TO_TMPFS_NODE(vp);
370 	int error = 0;
371 	int kflags = 0;
372 
373 	TMPFS_NODE_LOCK(node);
374 	if (error == 0 && (vap->va_flags != VNOVAL)) {
375 		error = tmpfs_chflags(vp, vap->va_flags, cred);
376 		kflags |= NOTE_ATTRIB;
377 	}
378 
379 	if (error == 0 && (vap->va_size != VNOVAL)) {
380 		if (vap->va_size > node->tn_size)
381 			kflags |= NOTE_WRITE | NOTE_EXTEND;
382 		else
383 			kflags |= NOTE_WRITE;
384 		error = tmpfs_chsize(vp, vap->va_size, cred);
385 	}
386 
387 	if (error == 0 && (vap->va_uid != (uid_t)VNOVAL ||
388 			   vap->va_gid != (gid_t)VNOVAL)) {
389 		error = tmpfs_chown(vp, vap->va_uid, vap->va_gid, cred);
390 		kflags |= NOTE_ATTRIB;
391 	}
392 
393 	if (error == 0 && (vap->va_mode != (mode_t)VNOVAL)) {
394 		error = tmpfs_chmod(vp, vap->va_mode, cred);
395 		kflags |= NOTE_ATTRIB;
396 	}
397 
398 	if (error == 0 && ((vap->va_atime.tv_sec != VNOVAL &&
399 	    vap->va_atime.tv_nsec != VNOVAL) ||
400 	    (vap->va_mtime.tv_sec != VNOVAL &&
401 	    vap->va_mtime.tv_nsec != VNOVAL) )) {
402 		error = tmpfs_chtimes(vp, &vap->va_atime, &vap->va_mtime,
403 				      vap->va_vaflags, cred);
404 		kflags |= NOTE_ATTRIB;
405 	}
406 
407 	/*
408 	 * Update the node times.  We give preference to the error codes
409 	 * generated by this function rather than the ones that may arise
410 	 * from tmpfs_update.
411 	 */
412 	tmpfs_update(vp);
413 	TMPFS_NODE_UNLOCK(node);
414 	tmpfs_knote(vp, kflags);
415 
416 	return (error);
417 }
418 
419 /* --------------------------------------------------------------------- */
420 
421 /*
422  * fsync is usually a NOP, but we must take action when unmounting or
423  * when recycling.
424  */
425 static int
426 tmpfs_fsync(struct vop_fsync_args *v)
427 {
428 	struct tmpfs_node *node;
429 	struct vnode *vp = v->a_vp;
430 
431 	node = VP_TO_TMPFS_NODE(vp);
432 
433 	tmpfs_update(vp);
434 	if (vp->v_type == VREG) {
435 		if (vp->v_flag & VRECLAIMED) {
436 			if (node->tn_links == 0)
437 				tmpfs_truncate(vp, 0);
438 			else
439 				vfsync(v->a_vp, v->a_waitfor, 1, NULL, NULL);
440 		}
441 	}
442 	return 0;
443 }
444 
445 /* --------------------------------------------------------------------- */
446 
447 static int
448 tmpfs_read (struct vop_read_args *ap)
449 {
450 	struct buf *bp;
451 	struct vnode *vp = ap->a_vp;
452 	struct uio *uio = ap->a_uio;
453 	struct tmpfs_node *node;
454 	off_t base_offset;
455 	size_t offset;
456 	size_t len;
457 	size_t resid;
458 	int error;
459 
460 	/*
461 	 * Check the basics
462 	 */
463 	if (uio->uio_offset < 0)
464 		return (EINVAL);
465 	if (vp->v_type != VREG)
466 		return (EINVAL);
467 
468 	/*
469 	 * Extract node, try to shortcut the operation through
470 	 * the VM page cache, allowing us to avoid buffer cache
471 	 * overheads.
472 	 */
473 	node = VP_TO_TMPFS_NODE(vp);
474         resid = uio->uio_resid;
475         error = vop_helper_read_shortcut(ap);
476         if (error)
477                 return error;
478         if (uio->uio_resid == 0) {
479 		if (resid)
480 			goto finished;
481 		return error;
482 	}
483 
484 	/*
485 	 * Fall-through to our normal read code.
486 	 */
487 	while (uio->uio_resid > 0 && uio->uio_offset < node->tn_size) {
488 		/*
489 		 * Use buffer cache I/O (via tmpfs_strategy)
490 		 */
491 		offset = (size_t)uio->uio_offset & TMPFS_BLKMASK64;
492 		base_offset = (off_t)uio->uio_offset - offset;
493 		bp = getcacheblk(vp, base_offset, TMPFS_BLKSIZE, 0);
494 		if (bp == NULL) {
495 			error = bread(vp, base_offset, TMPFS_BLKSIZE, &bp);
496 			if (error) {
497 				brelse(bp);
498 				kprintf("tmpfs_read bread error %d\n", error);
499 				break;
500 			}
501 
502 			/*
503 			 * tmpfs pretty much fiddles directly with the VM
504 			 * system, don't let it exhaust it or we won't play
505 			 * nice with other processes.
506 			 *
507 			 * Only do this if the VOP is coming from a normal
508 			 * read/write.  The VM system handles the case for
509 			 * UIO_NOCOPY.
510 			 */
511 			if (uio->uio_segflg != UIO_NOCOPY)
512 				vm_wait_nominal();
513 		}
514 		bp->b_flags |= B_CLUSTEROK;
515 
516 		/*
517 		 * Figure out how many bytes we can actually copy this loop.
518 		 */
519 		len = TMPFS_BLKSIZE - offset;
520 		if (len > uio->uio_resid)
521 			len = uio->uio_resid;
522 		if (len > node->tn_size - uio->uio_offset)
523 			len = (size_t)(node->tn_size - uio->uio_offset);
524 
525 		error = uiomovebp(bp, (char *)bp->b_data + offset, len, uio);
526 		bqrelse(bp);
527 		if (error) {
528 			kprintf("tmpfs_read uiomove error %d\n", error);
529 			break;
530 		}
531 	}
532 
533 finished:
534 	if ((node->tn_status & TMPFS_NODE_ACCESSED) == 0) {
535 		TMPFS_NODE_LOCK(node);
536 		node->tn_status |= TMPFS_NODE_ACCESSED;
537 		TMPFS_NODE_UNLOCK(node);
538 	}
539 	return (error);
540 }
541 
542 static int
543 tmpfs_write (struct vop_write_args *ap)
544 {
545 	struct buf *bp;
546 	struct vnode *vp = ap->a_vp;
547 	struct uio *uio = ap->a_uio;
548 	struct thread *td = uio->uio_td;
549 	struct tmpfs_node *node;
550 	boolean_t extended;
551 	off_t oldsize;
552 	int error;
553 	off_t base_offset;
554 	size_t offset;
555 	size_t len;
556 	struct rlimit limit;
557 	int trivial = 0;
558 	int kflags = 0;
559 	int seqcount;
560 
561 	error = 0;
562 	if (uio->uio_resid == 0) {
563 		return error;
564 	}
565 
566 	node = VP_TO_TMPFS_NODE(vp);
567 
568 	if (vp->v_type != VREG)
569 		return (EINVAL);
570 	seqcount = ap->a_ioflag >> 16;
571 
572 	oldsize = node->tn_size;
573 	if (ap->a_ioflag & IO_APPEND)
574 		uio->uio_offset = node->tn_size;
575 
576 	/*
577 	 * Check for illegal write offsets.
578 	 */
579 	if (uio->uio_offset + uio->uio_resid >
580 	  VFS_TO_TMPFS(vp->v_mount)->tm_maxfilesize) {
581 		return (EFBIG);
582 	}
583 
584 	/*
585 	 * NOTE: Ignore if UIO does not come from a user thread (e.g. VN).
586 	 */
587 	if (vp->v_type == VREG && td != NULL && td->td_lwp != NULL) {
588 		error = kern_getrlimit(RLIMIT_FSIZE, &limit);
589 		if (error != 0) {
590 			return error;
591 		}
592 		if (uio->uio_offset + uio->uio_resid > limit.rlim_cur) {
593 			ksignal(td->td_proc, SIGXFSZ);
594 			return (EFBIG);
595 		}
596 	}
597 
598 
599 	/*
600 	 * Extend the file's size if necessary
601 	 */
602 	extended = ((uio->uio_offset + uio->uio_resid) > node->tn_size);
603 
604 	while (uio->uio_resid > 0) {
605 		/*
606 		 * Don't completely blow out running buffer I/O
607 		 * when being hit from the pageout daemon.
608 		 */
609 		if (uio->uio_segflg == UIO_NOCOPY &&
610 		    (ap->a_ioflag & IO_RECURSE) == 0) {
611 			bwillwrite(TMPFS_BLKSIZE);
612 		}
613 
614 		/*
615 		 * Use buffer cache I/O (via tmpfs_strategy)
616 		 */
617 		offset = (size_t)uio->uio_offset & TMPFS_BLKMASK64;
618 		base_offset = (off_t)uio->uio_offset - offset;
619 		len = TMPFS_BLKSIZE - offset;
620 		if (len > uio->uio_resid)
621 			len = uio->uio_resid;
622 
623 		if ((uio->uio_offset + len) > node->tn_size) {
624 			trivial = (uio->uio_offset <= node->tn_size);
625 			error = tmpfs_reg_resize(vp, uio->uio_offset + len,  trivial);
626 			if (error)
627 				break;
628 		}
629 
630 		/*
631 		 * Read to fill in any gaps.  Theoretically we could
632 		 * optimize this if the write covers the entire buffer
633 		 * and is not a UIO_NOCOPY write, however this can lead
634 		 * to a security violation exposing random kernel memory
635 		 * (whatever junk was in the backing VM pages before).
636 		 *
637 		 * So just use bread() to do the right thing.
638 		 */
639 		error = bread(vp, base_offset, TMPFS_BLKSIZE, &bp);
640 		error = uiomovebp(bp, (char *)bp->b_data + offset, len, uio);
641 		if (error) {
642 			kprintf("tmpfs_write uiomove error %d\n", error);
643 			brelse(bp);
644 			break;
645 		}
646 
647 		if (uio->uio_offset > node->tn_size) {
648 			node->tn_size = uio->uio_offset;
649 			kflags |= NOTE_EXTEND;
650 		}
651 		kflags |= NOTE_WRITE;
652 
653 		/*
654 		 * Always try to flush the page in the UIO_NOCOPY case.  This
655 		 * can come from the pageout daemon or during vnode eviction.
656 		 * It is not necessarily going to be marked IO_ASYNC/IO_SYNC.
657 		 *
658 		 * For the normal case we buwrite(), dirtying the underlying
659 		 * VM pages instead of dirtying the buffer and releasing the
660 		 * buffer as a clean buffer.  This allows tmpfs to use
661 		 * essentially all available memory to cache file data.
662 		 * If we used bdwrite() the buffer cache would wind up
663 		 * flushing the data to swap too quickly.
664 		 *
665 		 * But because tmpfs can seriously load the VM system we
666 		 * fall-back to using bdwrite() when free memory starts
667 		 * to get low.  This shifts the load away from the VM system
668 		 * and makes tmpfs act more like a normal filesystem with
669 		 * regards to disk activity.
670 		 *
671 		 * tmpfs pretty much fiddles directly with the VM
672 		 * system, don't let it exhaust it or we won't play
673 		 * nice with other processes.  Only do this if the
674 		 * VOP is coming from a normal read/write.  The VM system
675 		 * handles the case for UIO_NOCOPY.
676 		 */
677 		bp->b_flags |= B_CLUSTEROK;
678 		if (uio->uio_segflg == UIO_NOCOPY) {
679 			/*
680 			 * Flush from the pageout daemon, deal with
681 			 * potentially very heavy tmpfs write activity
682 			 * causing long stalls in the pageout daemon
683 			 * before pages get to free/cache.
684 			 *
685 			 * (a) Under severe pressure setting B_DIRECT will
686 			 *     cause a buffer release to try to free the
687 			 *     underlying pages.
688 			 *
689 			 * (b) Under modest memory pressure the B_RELBUF
690 			 *     alone is sufficient to get the pages moved
691 			 *     to the cache.  We could also force this by
692 			 *     setting B_NOTMETA but that might have other
693 			 *     unintended side-effects (e.g. setting
694 			 *     PG_NOTMETA on the VM page).
695 			 *
696 			 * Hopefully this will unblock the VM system more
697 			 * quickly under extreme tmpfs write load.
698 			 */
699 			if (vm_page_count_min(vm_page_free_hysteresis))
700 				bp->b_flags |= B_DIRECT;
701 			bp->b_flags |= B_AGE | B_RELBUF;
702 			bp->b_act_count = 0;	/* buffer->deactivate pgs */
703 			cluster_awrite(bp);
704 		} else if (vm_page_count_target()) {
705 			/*
706 			 * Normal (userland) write but we are low on memory,
707 			 * run the buffer the buffer cache.
708 			 */
709 			bp->b_act_count = 0;	/* buffer->deactivate pgs */
710 			bdwrite(bp);
711 		} else {
712 			/*
713 			 * Otherwise run the buffer directly through to the
714 			 * backing VM store.
715 			 */
716 			buwrite(bp);
717 			/*vm_wait_nominal();*/
718 		}
719 
720 		if (bp->b_error) {
721 			kprintf("tmpfs_write bwrite error %d\n", bp->b_error);
722 			break;
723 		}
724 	}
725 
726 	if (error) {
727 		if (extended) {
728 			(void)tmpfs_reg_resize(vp, oldsize, trivial);
729 			kflags &= ~NOTE_EXTEND;
730 		}
731 		goto done;
732 	}
733 
734 	/*
735 	 * Currently we don't set the mtime on files modified via mmap()
736 	 * because we can't tell the difference between those modifications
737 	 * and an attempt by the pageout daemon to flush tmpfs pages to
738 	 * swap.
739 	 *
740 	 * This is because in order to defer flushes as long as possible
741 	 * buwrite() works by marking the underlying VM pages dirty in
742 	 * order to be able to dispose of the buffer cache buffer without
743 	 * flushing it.
744 	 */
745 	TMPFS_NODE_LOCK(node);
746 	if (uio->uio_segflg != UIO_NOCOPY)
747 		node->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED;
748 	if (extended)
749 		node->tn_status |= TMPFS_NODE_CHANGED;
750 
751 	if (node->tn_mode & (S_ISUID | S_ISGID)) {
752 		if (priv_check_cred(ap->a_cred, PRIV_VFS_RETAINSUGID, 0))
753 			node->tn_mode &= ~(S_ISUID | S_ISGID);
754 	}
755 	TMPFS_NODE_UNLOCK(node);
756 done:
757 	tmpfs_knote(vp, kflags);
758 
759 	return(error);
760 }
761 
762 static int
763 tmpfs_advlock (struct vop_advlock_args *ap)
764 {
765 	struct tmpfs_node *node;
766 	struct vnode *vp = ap->a_vp;
767 	int error;
768 
769 	node = VP_TO_TMPFS_NODE(vp);
770 	error = (lf_advlock(ap, &node->tn_advlock, node->tn_size));
771 
772 	return (error);
773 }
774 
775 /*
776  * The strategy function is typically only called when memory pressure
777  * forces the system to attempt to pageout pages.  It can also be called
778  * by [n]vtruncbuf() when a truncation cuts a page in half.  Normal write
779  * operations
780  */
781 static int
782 tmpfs_strategy(struct vop_strategy_args *ap)
783 {
784 	struct bio *bio = ap->a_bio;
785 	struct bio *nbio;
786 	struct buf *bp = bio->bio_buf;
787 	struct vnode *vp = ap->a_vp;
788 	struct tmpfs_node *node;
789 	vm_object_t uobj;
790 	vm_page_t m;
791 	int i;
792 
793 	if (vp->v_type != VREG) {
794 		bp->b_resid = bp->b_bcount;
795 		bp->b_flags |= B_ERROR | B_INVAL;
796 		bp->b_error = EINVAL;
797 		biodone(bio);
798 		return(0);
799 	}
800 
801 	node = VP_TO_TMPFS_NODE(vp);
802 
803 	uobj = node->tn_reg.tn_aobj;
804 
805 	/*
806 	 * Don't bother flushing to swap if there is no swap, just
807 	 * ensure that the pages are marked as needing a commit (still).
808 	 */
809 	if (bp->b_cmd == BUF_CMD_WRITE && vm_swap_size == 0) {
810 		for (i = 0; i < bp->b_xio.xio_npages; ++i) {
811 			m = bp->b_xio.xio_pages[i];
812 			vm_page_need_commit(m);
813 		}
814 		bp->b_resid = 0;
815 		bp->b_error = 0;
816 		biodone(bio);
817 	} else {
818 		nbio = push_bio(bio);
819 		nbio->bio_done = tmpfs_strategy_done;
820 		nbio->bio_offset = bio->bio_offset;
821 		swap_pager_strategy(uobj, nbio);
822 	}
823 	return 0;
824 }
825 
826 /*
827  * If we were unable to commit the pages to swap make sure they are marked
828  * as needing a commit (again).  If we were, clear the flag to allow the
829  * pages to be freed.
830  */
831 static void
832 tmpfs_strategy_done(struct bio *bio)
833 {
834 	struct buf *bp;
835 	vm_page_t m;
836 	int i;
837 
838 	bp = bio->bio_buf;
839 
840 	if (bp->b_flags & B_ERROR) {
841 		bp->b_flags &= ~B_ERROR;
842 		bp->b_error = 0;
843 		bp->b_resid = 0;
844 		for (i = 0; i < bp->b_xio.xio_npages; ++i) {
845 			m = bp->b_xio.xio_pages[i];
846 			vm_page_need_commit(m);
847 		}
848 	} else {
849 		for (i = 0; i < bp->b_xio.xio_npages; ++i) {
850 			m = bp->b_xio.xio_pages[i];
851 			vm_page_clear_commit(m);
852 		}
853 	}
854 	bio = pop_bio(bio);
855 	biodone(bio);
856 }
857 
858 static int
859 tmpfs_bmap(struct vop_bmap_args *ap)
860 {
861 	if (ap->a_doffsetp != NULL)
862 		*ap->a_doffsetp = ap->a_loffset;
863 	if (ap->a_runp != NULL)
864 		*ap->a_runp = 0;
865 	if (ap->a_runb != NULL)
866 		*ap->a_runb = 0;
867 
868 	return 0;
869 }
870 
871 /* --------------------------------------------------------------------- */
872 
873 static int
874 tmpfs_nremove(struct vop_nremove_args *v)
875 {
876 	struct vnode *dvp = v->a_dvp;
877 	struct namecache *ncp = v->a_nch->ncp;
878 	struct vnode *vp;
879 	int error;
880 	struct tmpfs_dirent *de;
881 	struct tmpfs_mount *tmp;
882 	struct tmpfs_node *dnode;
883 	struct tmpfs_node *node;
884 	struct mount *mp;
885 
886 	mp = dvp->v_mount;
887 
888 	/*
889 	 * We have to acquire the vp from v->a_nch because we will likely
890 	 * unresolve the namecache entry, and a vrele/vput is needed to
891 	 * trigger the tmpfs_inactive/tmpfs_reclaim sequence.
892 	 *
893 	 * We have to use vget to clear any inactive state on the vnode,
894 	 * otherwise the vnode may remain inactive and thus tmpfs_inactive
895 	 * will not get called when we release it.
896 	 */
897 	error = cache_vget(v->a_nch, v->a_cred, LK_SHARED, &vp);
898 	KKASSERT(vp->v_mount == dvp->v_mount);
899 	KKASSERT(error == 0);
900 	vn_unlock(vp);
901 
902 	if (vp->v_type == VDIR) {
903 		error = EISDIR;
904 		goto out2;
905 	}
906 
907 	dnode = VP_TO_TMPFS_DIR(dvp);
908 	node = VP_TO_TMPFS_NODE(vp);
909 	tmp = VFS_TO_TMPFS(vp->v_mount);
910 
911 	TMPFS_NODE_LOCK(dnode);
912 	de = tmpfs_dir_lookup(dnode, node, ncp);
913 	if (de == NULL) {
914 		error = ENOENT;
915 		goto out;
916 	}
917 
918 	/* Files marked as immutable or append-only cannot be deleted. */
919 	if ((node->tn_flags & (IMMUTABLE | APPEND | NOUNLINK)) ||
920 	    (dnode->tn_flags & APPEND)) {
921 		error = EPERM;
922 		goto out;
923 	}
924 
925 	/* Remove the entry from the directory; as it is a file, we do not
926 	 * have to change the number of hard links of the directory. */
927 	tmpfs_dir_detach(dnode, de);
928 
929 	/* Free the directory entry we just deleted.  Note that the node
930 	 * referred by it will not be removed until the vnode is really
931 	 * reclaimed. */
932 	tmpfs_free_dirent(tmp, de);
933 
934 	if (node->tn_links > 0) {
935 	        TMPFS_NODE_LOCK(node);
936 		node->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED | \
937 	                TMPFS_NODE_MODIFIED;
938 	        TMPFS_NODE_UNLOCK(node);
939 	}
940 
941 	cache_unlink(v->a_nch);
942 	tmpfs_knote(vp, NOTE_DELETE);
943 	error = 0;
944 
945 out:
946 	TMPFS_NODE_UNLOCK(dnode);
947 	if (error == 0)
948 		tmpfs_knote(dvp, NOTE_WRITE);
949 out2:
950 	vrele(vp);
951 
952 	return error;
953 }
954 
955 /* --------------------------------------------------------------------- */
956 
957 static int
958 tmpfs_nlink(struct vop_nlink_args *v)
959 {
960 	struct vnode *dvp = v->a_dvp;
961 	struct vnode *vp = v->a_vp;
962 	struct namecache *ncp = v->a_nch->ncp;
963 	struct tmpfs_dirent *de;
964 	struct tmpfs_node *node;
965 	struct tmpfs_node *dnode;
966 	struct mount *mp;
967 	int error;
968 
969 	if (dvp->v_mount != vp->v_mount)
970 		return(EXDEV);
971 	mp = dvp->v_mount;
972 
973 	KKASSERT(dvp != vp); /* XXX When can this be false? */
974 
975 	node = VP_TO_TMPFS_NODE(vp);
976 	dnode = VP_TO_TMPFS_NODE(dvp);
977 	TMPFS_NODE_LOCK(dnode);
978 
979 	/* XXX: Why aren't the following two tests done by the caller? */
980 
981 	/* Hard links of directories are forbidden. */
982 	if (vp->v_type == VDIR) {
983 		error = EPERM;
984 		goto out;
985 	}
986 
987 	/* Cannot create cross-device links. */
988 	if (dvp->v_mount != vp->v_mount) {
989 		error = EXDEV;
990 		goto out;
991 	}
992 
993 	/* Ensure that we do not overflow the maximum number of links imposed
994 	 * by the system. */
995 	KKASSERT(node->tn_links <= LINK_MAX);
996 	if (node->tn_links >= LINK_MAX) {
997 		error = EMLINK;
998 		goto out;
999 	}
1000 
1001 	/* We cannot create links of files marked immutable or append-only. */
1002 	if (node->tn_flags & (IMMUTABLE | APPEND)) {
1003 		error = EPERM;
1004 		goto out;
1005 	}
1006 
1007 	/* Allocate a new directory entry to represent the node. */
1008 	error = tmpfs_alloc_dirent(VFS_TO_TMPFS(vp->v_mount), node,
1009 				   ncp->nc_name, ncp->nc_nlen, &de);
1010 	if (error != 0)
1011 		goto out;
1012 
1013 	/* Insert the new directory entry into the appropriate directory. */
1014 	tmpfs_dir_attach(dnode, de);
1015 
1016 	/* vp link count has changed, so update node times. */
1017 
1018 	TMPFS_NODE_LOCK(node);
1019 	node->tn_status |= TMPFS_NODE_CHANGED;
1020 	TMPFS_NODE_UNLOCK(node);
1021 	tmpfs_update(vp);
1022 
1023 	tmpfs_knote(vp, NOTE_LINK);
1024 	cache_setunresolved(v->a_nch);
1025 	cache_setvp(v->a_nch, vp);
1026 	error = 0;
1027 
1028 out:
1029 	TMPFS_NODE_UNLOCK(dnode);
1030 	if (error == 0)
1031 		tmpfs_knote(dvp, NOTE_WRITE);
1032 	return error;
1033 }
1034 
1035 /* --------------------------------------------------------------------- */
1036 
1037 static int
1038 tmpfs_nrename(struct vop_nrename_args *v)
1039 {
1040 	struct vnode *fdvp = v->a_fdvp;
1041 	struct namecache *fncp = v->a_fnch->ncp;
1042 	struct vnode *fvp = fncp->nc_vp;
1043 	struct vnode *tdvp = v->a_tdvp;
1044 	struct namecache *tncp = v->a_tnch->ncp;
1045 	struct vnode *tvp;
1046 	struct tmpfs_dirent *de, *tde;
1047 	struct tmpfs_mount *tmp;
1048 	struct tmpfs_node *fdnode;
1049 	struct tmpfs_node *fnode;
1050 	struct tmpfs_node *tnode;
1051 	struct tmpfs_node *tdnode;
1052 	struct mount *mp;
1053 	char *newname;
1054 	char *oldname;
1055 	int error;
1056 
1057 	mp = fdvp->v_mount;
1058 	KKASSERT(fdvp->v_mount == fvp->v_mount);
1059 
1060 	/*
1061 	 * Because tvp can get overwritten we have to vget it instead of
1062 	 * just vref or use it, otherwise it's VINACTIVE flag may not get
1063 	 * cleared and the node won't get destroyed.
1064 	 */
1065 	error = cache_vget(v->a_tnch, v->a_cred, LK_SHARED, &tvp);
1066 	if (error == 0) {
1067 		tnode = VP_TO_TMPFS_NODE(tvp);
1068 		vn_unlock(tvp);
1069 	} else {
1070 		tnode = NULL;
1071 	}
1072 
1073 	/* Disallow cross-device renames.
1074 	 * XXX Why isn't this done by the caller? */
1075 	if (fvp->v_mount != tdvp->v_mount ||
1076 	    (tvp != NULL && fvp->v_mount != tvp->v_mount)) {
1077 		error = EXDEV;
1078 		goto out;
1079 	}
1080 
1081 	tmp = VFS_TO_TMPFS(tdvp->v_mount);
1082 	tdnode = VP_TO_TMPFS_DIR(tdvp);
1083 
1084 	/* If source and target are the same file, there is nothing to do. */
1085 	if (fvp == tvp) {
1086 		error = 0;
1087 		goto out;
1088 	}
1089 
1090 	fdnode = VP_TO_TMPFS_DIR(fdvp);
1091 	fnode = VP_TO_TMPFS_NODE(fvp);
1092 	TMPFS_NODE_LOCK(fdnode);
1093 	de = tmpfs_dir_lookup(fdnode, fnode, fncp);
1094 	TMPFS_NODE_UNLOCK(fdnode);	/* XXX depend on namecache lock */
1095 
1096 	/* Avoid manipulating '.' and '..' entries. */
1097 	if (de == NULL) {
1098 		error = ENOENT;
1099 		goto out_locked;
1100 	}
1101 	KKASSERT(de->td_node == fnode);
1102 
1103 	/*
1104 	 * If replacing an entry in the target directory and that entry
1105 	 * is a directory, it must be empty.
1106 	 *
1107 	 * Kern_rename gurantees the destination to be a directory
1108 	 * if the source is one (it does?).
1109 	 */
1110 	if (tvp != NULL) {
1111 		KKASSERT(tnode != NULL);
1112 
1113 		if ((tnode->tn_flags & (NOUNLINK | IMMUTABLE | APPEND)) ||
1114 		    (tdnode->tn_flags & (APPEND | IMMUTABLE))) {
1115 			error = EPERM;
1116 			goto out_locked;
1117 		}
1118 
1119 		if (fnode->tn_type == VDIR && tnode->tn_type == VDIR) {
1120 			if (tnode->tn_size > 0) {
1121 				error = ENOTEMPTY;
1122 				goto out_locked;
1123 			}
1124 		} else if (fnode->tn_type == VDIR && tnode->tn_type != VDIR) {
1125 			error = ENOTDIR;
1126 			goto out_locked;
1127 		} else if (fnode->tn_type != VDIR && tnode->tn_type == VDIR) {
1128 			error = EISDIR;
1129 			goto out_locked;
1130 		} else {
1131 			KKASSERT(fnode->tn_type != VDIR &&
1132 				tnode->tn_type != VDIR);
1133 		}
1134 	}
1135 
1136 	if ((fnode->tn_flags & (NOUNLINK | IMMUTABLE | APPEND)) ||
1137 	    (fdnode->tn_flags & (APPEND | IMMUTABLE))) {
1138 		error = EPERM;
1139 		goto out_locked;
1140 	}
1141 
1142 	/*
1143 	 * Ensure that we have enough memory to hold the new name, if it
1144 	 * has to be changed.
1145 	 */
1146 	if (fncp->nc_nlen != tncp->nc_nlen ||
1147 	    bcmp(fncp->nc_name, tncp->nc_name, fncp->nc_nlen) != 0) {
1148 		newname = kmalloc(tncp->nc_nlen + 1, tmp->tm_name_zone,
1149 				  M_WAITOK | M_NULLOK);
1150 		if (newname == NULL) {
1151 			error = ENOSPC;
1152 			goto out_locked;
1153 		}
1154 		bcopy(tncp->nc_name, newname, tncp->nc_nlen);
1155 		newname[tncp->nc_nlen] = '\0';
1156 	} else {
1157 		newname = NULL;
1158 	}
1159 
1160 	/*
1161 	 * Unlink entry from source directory.  Note that the kernel has
1162 	 * already checked for illegal recursion cases (renaming a directory
1163 	 * into a subdirectory of itself).
1164 	 */
1165 	if (fdnode != tdnode) {
1166 		tmpfs_dir_detach(fdnode, de);
1167 	} else {
1168 		/* XXX depend on namecache lock */
1169 		TMPFS_NODE_LOCK(fdnode);
1170 		KKASSERT(de == tmpfs_dir_lookup(fdnode, fnode, fncp));
1171 		RB_REMOVE(tmpfs_dirtree, &fdnode->tn_dir.tn_dirtree, de);
1172 		RB_REMOVE(tmpfs_dirtree_cookie,
1173 			  &fdnode->tn_dir.tn_cookietree, de);
1174 		TMPFS_NODE_UNLOCK(fdnode);
1175 	}
1176 
1177 	/*
1178 	 * Handle any name change.  Swap with newname, we will
1179 	 * deallocate it at the end.
1180 	 */
1181 	if (newname != NULL) {
1182 #if 0
1183 		TMPFS_NODE_LOCK(fnode);
1184 		fnode->tn_status |= TMPFS_NODE_CHANGED;
1185 		TMPFS_NODE_UNLOCK(fnode);
1186 #endif
1187 		oldname = de->td_name;
1188 		de->td_name = newname;
1189 		de->td_namelen = (uint16_t)tncp->nc_nlen;
1190 		newname = oldname;
1191 	}
1192 
1193 	/*
1194 	 * If we are overwriting an entry, we have to remove the old one
1195 	 * from the target directory.
1196 	 */
1197 	if (tvp != NULL) {
1198 		/* Remove the old entry from the target directory. */
1199 		TMPFS_NODE_LOCK(tdnode);
1200 		tde = tmpfs_dir_lookup(tdnode, tnode, tncp);
1201 		tmpfs_dir_detach(tdnode, tde);
1202 		TMPFS_NODE_UNLOCK(tdnode);
1203 		tmpfs_knote(tdnode->tn_vnode, NOTE_DELETE);
1204 
1205 		/*
1206 		 * Free the directory entry we just deleted.  Note that the
1207 		 * node referred by it will not be removed until the vnode is
1208 		 * really reclaimed.
1209 		 */
1210 		tmpfs_free_dirent(VFS_TO_TMPFS(tvp->v_mount), tde);
1211 		/*cache_inval_vp(tvp, CINV_DESTROY);*/
1212 	}
1213 
1214 	/*
1215 	 * Link entry to target directory.  If the entry
1216 	 * represents a directory move the parent linkage
1217 	 * as well.
1218 	 */
1219 	if (fdnode != tdnode) {
1220 		if (de->td_node->tn_type == VDIR) {
1221 			TMPFS_VALIDATE_DIR(fnode);
1222 		}
1223 		tmpfs_dir_attach(tdnode, de);
1224 	} else {
1225 		TMPFS_NODE_LOCK(tdnode);
1226 		tdnode->tn_status |= TMPFS_NODE_MODIFIED;
1227 		RB_INSERT(tmpfs_dirtree, &tdnode->tn_dir.tn_dirtree, de);
1228 		RB_INSERT(tmpfs_dirtree_cookie,
1229 			  &tdnode->tn_dir.tn_cookietree, de);
1230 		TMPFS_NODE_UNLOCK(tdnode);
1231 	}
1232 
1233 	/*
1234 	 * Finish up
1235 	 */
1236 	if (newname) {
1237 		kfree(newname, tmp->tm_name_zone);
1238 		newname = NULL;
1239 	}
1240 	cache_rename(v->a_fnch, v->a_tnch);
1241 	tmpfs_knote(v->a_fdvp, NOTE_WRITE);
1242 	tmpfs_knote(v->a_tdvp, NOTE_WRITE);
1243 	if (fnode->tn_vnode)
1244 		tmpfs_knote(fnode->tn_vnode, NOTE_RENAME);
1245 	error = 0;
1246 
1247 out_locked:
1248 	;
1249 out:
1250 	if (tvp)
1251 		vrele(tvp);
1252 	return error;
1253 }
1254 
1255 /* --------------------------------------------------------------------- */
1256 
1257 static int
1258 tmpfs_nmkdir(struct vop_nmkdir_args *v)
1259 {
1260 	struct vnode *dvp = v->a_dvp;
1261 	struct vnode **vpp = v->a_vpp;
1262 	struct namecache *ncp = v->a_nch->ncp;
1263 	struct vattr *vap = v->a_vap;
1264 	struct ucred *cred = v->a_cred;
1265 	struct mount *mp;
1266 	int error;
1267 
1268 	mp = dvp->v_mount;
1269 
1270 	KKASSERT(vap->va_type == VDIR);
1271 
1272 	error = tmpfs_alloc_file(dvp, vpp, vap, ncp, cred, NULL);
1273 	if (error == 0) {
1274 		cache_setunresolved(v->a_nch);
1275 		cache_setvp(v->a_nch, *vpp);
1276 		tmpfs_knote(dvp, NOTE_WRITE | NOTE_LINK);
1277 	}
1278 	return error;
1279 }
1280 
1281 /* --------------------------------------------------------------------- */
1282 
1283 static int
1284 tmpfs_nrmdir(struct vop_nrmdir_args *v)
1285 {
1286 	struct vnode *dvp = v->a_dvp;
1287 	struct namecache *ncp = v->a_nch->ncp;
1288 	struct vnode *vp;
1289 	struct tmpfs_dirent *de;
1290 	struct tmpfs_mount *tmp;
1291 	struct tmpfs_node *dnode;
1292 	struct tmpfs_node *node;
1293 	struct mount *mp;
1294 	int error;
1295 
1296 	mp = dvp->v_mount;
1297 
1298 	/*
1299 	 * We have to acquire the vp from v->a_nch because we will likely
1300 	 * unresolve the namecache entry, and a vrele/vput is needed to
1301 	 * trigger the tmpfs_inactive/tmpfs_reclaim sequence.
1302 	 *
1303 	 * We have to use vget to clear any inactive state on the vnode,
1304 	 * otherwise the vnode may remain inactive and thus tmpfs_inactive
1305 	 * will not get called when we release it.
1306 	 */
1307 	error = cache_vget(v->a_nch, v->a_cred, LK_SHARED, &vp);
1308 	KKASSERT(error == 0);
1309 	vn_unlock(vp);
1310 
1311 	/*
1312 	 * Prevalidate so we don't hit an assertion later
1313 	 */
1314 	if (vp->v_type != VDIR) {
1315 		error = ENOTDIR;
1316 		goto out;
1317 	}
1318 
1319 	tmp = VFS_TO_TMPFS(dvp->v_mount);
1320 	dnode = VP_TO_TMPFS_DIR(dvp);
1321 	node = VP_TO_TMPFS_DIR(vp);
1322 
1323 	/*
1324 	 * Directories with more than two entries ('.' and '..') cannot
1325 	 * be removed.
1326 	 */
1327 	if (node->tn_size > 0) {
1328 		error = ENOTEMPTY;
1329 		goto out;
1330 	}
1331 
1332 	if ((dnode->tn_flags & APPEND)
1333 	    || (node->tn_flags & (NOUNLINK | IMMUTABLE | APPEND))) {
1334 		error = EPERM;
1335 		goto out;
1336 	}
1337 
1338 	/*
1339 	 * This invariant holds only if we are not trying to
1340 	 * remove "..".  We checked for that above so this is safe now.
1341 	 */
1342 	KKASSERT(node->tn_dir.tn_parent == dnode);
1343 
1344 	/*
1345 	 * Get the directory entry associated with node (vp).  This
1346 	 * was filled by tmpfs_lookup while looking up the entry.
1347 	 */
1348 	TMPFS_NODE_LOCK(dnode);
1349 	de = tmpfs_dir_lookup(dnode, node, ncp);
1350 	KKASSERT(TMPFS_DIRENT_MATCHES(de, ncp->nc_name, ncp->nc_nlen));
1351 
1352 	/* Check flags to see if we are allowed to remove the directory. */
1353 	if ((dnode->tn_flags & APPEND) ||
1354 	    node->tn_flags & (NOUNLINK | IMMUTABLE | APPEND)) {
1355 		error = EPERM;
1356 		TMPFS_NODE_UNLOCK(dnode);
1357 		goto out;
1358 	}
1359 
1360 	/* Detach the directory entry from the directory (dnode). */
1361 	tmpfs_dir_detach(dnode, de);
1362 	TMPFS_NODE_UNLOCK(dnode);
1363 
1364 	/* No vnode should be allocated for this entry from this point */
1365 	TMPFS_NODE_LOCK(dnode);
1366 	TMPFS_ASSERT_ELOCKED(dnode);
1367 	TMPFS_NODE_LOCK(node);
1368 	TMPFS_ASSERT_ELOCKED(node);
1369 
1370 	/*
1371 	 * Must set parent linkage to NULL (tested by ncreate to disallow
1372 	 * the creation of new files/dirs in a deleted directory)
1373 	 */
1374 	node->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED |
1375 			   TMPFS_NODE_MODIFIED;
1376 
1377 	dnode->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED |
1378 			    TMPFS_NODE_MODIFIED;
1379 
1380 	TMPFS_NODE_UNLOCK(node);
1381 	TMPFS_NODE_UNLOCK(dnode);
1382 
1383 	/* Free the directory entry we just deleted.  Note that the node
1384 	 * referred by it will not be removed until the vnode is really
1385 	 * reclaimed. */
1386 	tmpfs_free_dirent(tmp, de);
1387 
1388 	/* Release the deleted vnode (will destroy the node, notify
1389 	 * interested parties and clean it from the cache). */
1390 
1391 	TMPFS_NODE_LOCK(dnode);
1392 	dnode->tn_status |= TMPFS_NODE_CHANGED;
1393 	TMPFS_NODE_UNLOCK(dnode);
1394 	tmpfs_update(dvp);
1395 
1396 	cache_unlink(v->a_nch);
1397 	tmpfs_knote(dvp, NOTE_WRITE | NOTE_LINK);
1398 	error = 0;
1399 
1400 out:
1401 	vrele(vp);
1402 
1403 	return error;
1404 }
1405 
1406 /* --------------------------------------------------------------------- */
1407 
1408 static int
1409 tmpfs_nsymlink(struct vop_nsymlink_args *v)
1410 {
1411 	struct vnode *dvp = v->a_dvp;
1412 	struct vnode **vpp = v->a_vpp;
1413 	struct namecache *ncp = v->a_nch->ncp;
1414 	struct vattr *vap = v->a_vap;
1415 	struct ucred *cred = v->a_cred;
1416 	char *target = v->a_target;
1417 	int error;
1418 
1419 	vap->va_type = VLNK;
1420 	error = tmpfs_alloc_file(dvp, vpp, vap, ncp, cred, target);
1421 	if (error == 0) {
1422 		tmpfs_knote(*vpp, NOTE_WRITE);
1423 		cache_setunresolved(v->a_nch);
1424 		cache_setvp(v->a_nch, *vpp);
1425 	}
1426 	return error;
1427 }
1428 
1429 /* --------------------------------------------------------------------- */
1430 
1431 static int
1432 tmpfs_readdir(struct vop_readdir_args *v)
1433 {
1434 	struct vnode *vp = v->a_vp;
1435 	struct uio *uio = v->a_uio;
1436 	int *eofflag = v->a_eofflag;
1437 	off_t **cookies = v->a_cookies;
1438 	int *ncookies = v->a_ncookies;
1439 	struct tmpfs_mount *tmp;
1440 	int error;
1441 	off_t startoff;
1442 	off_t cnt = 0;
1443 	struct tmpfs_node *node;
1444 
1445 	/* This operation only makes sense on directory nodes. */
1446 	if (vp->v_type != VDIR) {
1447 		return ENOTDIR;
1448 	}
1449 
1450 	tmp = VFS_TO_TMPFS(vp->v_mount);
1451 	node = VP_TO_TMPFS_DIR(vp);
1452 	startoff = uio->uio_offset;
1453 
1454 	if (uio->uio_offset == TMPFS_DIRCOOKIE_DOT) {
1455 		error = tmpfs_dir_getdotdent(node, uio);
1456 		if (error != 0) {
1457 			TMPFS_NODE_LOCK_SH(node);
1458 			goto outok;
1459 		}
1460 		cnt++;
1461 	}
1462 
1463 	if (uio->uio_offset == TMPFS_DIRCOOKIE_DOTDOT) {
1464 		/* may lock parent, cannot hold node lock */
1465 		error = tmpfs_dir_getdotdotdent(tmp, node, uio);
1466 		if (error != 0) {
1467 			TMPFS_NODE_LOCK_SH(node);
1468 			goto outok;
1469 		}
1470 		cnt++;
1471 	}
1472 
1473 	TMPFS_NODE_LOCK_SH(node);
1474 	error = tmpfs_dir_getdents(node, uio, &cnt);
1475 
1476 outok:
1477 	KKASSERT(error >= -1);
1478 
1479 	if (error == -1)
1480 		error = 0;
1481 
1482 	if (eofflag != NULL)
1483 		*eofflag =
1484 		    (error == 0 && uio->uio_offset == TMPFS_DIRCOOKIE_EOF);
1485 
1486 	/* Update NFS-related variables. */
1487 	if (error == 0 && cookies != NULL && ncookies != NULL) {
1488 		off_t i;
1489 		off_t off = startoff;
1490 		struct tmpfs_dirent *de = NULL;
1491 
1492 		*ncookies = cnt;
1493 		*cookies = kmalloc(cnt * sizeof(off_t), M_TEMP, M_WAITOK);
1494 
1495 		for (i = 0; i < cnt; i++) {
1496 			KKASSERT(off != TMPFS_DIRCOOKIE_EOF);
1497 			if (off == TMPFS_DIRCOOKIE_DOT) {
1498 				off = TMPFS_DIRCOOKIE_DOTDOT;
1499 			} else {
1500 				if (off == TMPFS_DIRCOOKIE_DOTDOT) {
1501 					de = RB_MIN(tmpfs_dirtree_cookie,
1502 						&node->tn_dir.tn_cookietree);
1503 				} else if (de != NULL) {
1504 					de = RB_NEXT(tmpfs_dirtree_cookie,
1505 					       &node->tn_dir.tn_cookietree, de);
1506 				} else {
1507 					de = tmpfs_dir_lookupbycookie(node,
1508 								      off);
1509 					KKASSERT(de != NULL);
1510 					de = RB_NEXT(tmpfs_dirtree_cookie,
1511 					       &node->tn_dir.tn_cookietree, de);
1512 				}
1513 				if (de == NULL)
1514 					off = TMPFS_DIRCOOKIE_EOF;
1515 				else
1516 					off = tmpfs_dircookie(de);
1517 			}
1518 			(*cookies)[i] = off;
1519 		}
1520 		KKASSERT(uio->uio_offset == off);
1521 	}
1522 	TMPFS_NODE_UNLOCK(node);
1523 
1524 	if ((node->tn_status & TMPFS_NODE_ACCESSED) == 0) {
1525 		TMPFS_NODE_LOCK(node);
1526 		node->tn_status |= TMPFS_NODE_ACCESSED;
1527 		TMPFS_NODE_UNLOCK(node);
1528 	}
1529 	return error;
1530 }
1531 
1532 /* --------------------------------------------------------------------- */
1533 
1534 static int
1535 tmpfs_readlink(struct vop_readlink_args *v)
1536 {
1537 	struct vnode *vp = v->a_vp;
1538 	struct uio *uio = v->a_uio;
1539 	int error;
1540 	struct tmpfs_node *node;
1541 
1542 	KKASSERT(uio->uio_offset == 0);
1543 	KKASSERT(vp->v_type == VLNK);
1544 
1545 	node = VP_TO_TMPFS_NODE(vp);
1546 	TMPFS_NODE_LOCK_SH(node);
1547 	error = uiomove(node->tn_link,
1548 			MIN(node->tn_size, uio->uio_resid), uio);
1549 	TMPFS_NODE_UNLOCK(node);
1550 	if ((node->tn_status & TMPFS_NODE_ACCESSED) == 0) {
1551 		TMPFS_NODE_LOCK(node);
1552 		node->tn_status |= TMPFS_NODE_ACCESSED;
1553 		TMPFS_NODE_UNLOCK(node);
1554 	}
1555 	return error;
1556 }
1557 
1558 /* --------------------------------------------------------------------- */
1559 
1560 static int
1561 tmpfs_inactive(struct vop_inactive_args *v)
1562 {
1563 	struct vnode *vp = v->a_vp;
1564 	struct tmpfs_node *node;
1565 	struct mount *mp;
1566 
1567 	mp = vp->v_mount;
1568 	lwkt_gettoken(&mp->mnt_token);
1569 	node = VP_TO_TMPFS_NODE(vp);
1570 
1571 	/*
1572 	 * Degenerate case
1573 	 */
1574 	if (node == NULL) {
1575 		vrecycle(vp);
1576 		lwkt_reltoken(&mp->mnt_token);
1577 		return(0);
1578 	}
1579 
1580 	/*
1581 	 * Get rid of unreferenced deleted vnodes sooner rather than
1582 	 * later so the data memory can be recovered immediately.
1583 	 *
1584 	 * We must truncate the vnode to prevent the normal reclamation
1585 	 * path from flushing the data for the removed file to disk.
1586 	 */
1587 	TMPFS_NODE_LOCK(node);
1588 	if ((node->tn_vpstate & TMPFS_VNODE_ALLOCATING) == 0 &&
1589 	    node->tn_links == 0)
1590 	{
1591 		node->tn_vpstate = TMPFS_VNODE_DOOMED;
1592 		TMPFS_NODE_UNLOCK(node);
1593 		if (node->tn_type == VREG)
1594 			tmpfs_truncate(vp, 0);
1595 		vrecycle(vp);
1596 	} else {
1597 		TMPFS_NODE_UNLOCK(node);
1598 	}
1599 	lwkt_reltoken(&mp->mnt_token);
1600 
1601 	return 0;
1602 }
1603 
1604 /* --------------------------------------------------------------------- */
1605 
1606 int
1607 tmpfs_reclaim(struct vop_reclaim_args *v)
1608 {
1609 	struct vnode *vp = v->a_vp;
1610 	struct tmpfs_mount *tmp;
1611 	struct tmpfs_node *node;
1612 	struct mount *mp;
1613 
1614 	mp = vp->v_mount;
1615 	lwkt_gettoken(&mp->mnt_token);
1616 
1617 	node = VP_TO_TMPFS_NODE(vp);
1618 	tmp = VFS_TO_TMPFS(vp->v_mount);
1619 	KKASSERT(mp == tmp->tm_mount);
1620 
1621 	tmpfs_free_vp(vp);
1622 
1623 	/*
1624 	 * If the node referenced by this vnode was deleted by the
1625 	 * user, we must free its associated data structures now that
1626 	 * the vnode is being reclaimed.
1627 	 *
1628 	 * Directories have an extra link ref.
1629 	 */
1630 	TMPFS_NODE_LOCK(node);
1631 	if ((node->tn_vpstate & TMPFS_VNODE_ALLOCATING) == 0 &&
1632 	    node->tn_links == 0) {
1633 		node->tn_vpstate = TMPFS_VNODE_DOOMED;
1634 		tmpfs_free_node(tmp, node);
1635 		/* eats the lock */
1636 	} else {
1637 		TMPFS_NODE_UNLOCK(node);
1638 	}
1639 	lwkt_reltoken(&mp->mnt_token);
1640 
1641 	KKASSERT(vp->v_data == NULL);
1642 	return 0;
1643 }
1644 
1645 /* --------------------------------------------------------------------- */
1646 
1647 static int
1648 tmpfs_mountctl(struct vop_mountctl_args *ap)
1649 {
1650 	struct tmpfs_mount *tmp;
1651 	struct mount *mp;
1652 	int rc;
1653 
1654 	mp = ap->a_head.a_ops->head.vv_mount;
1655 	lwkt_gettoken(&mp->mnt_token);
1656 
1657 	switch (ap->a_op) {
1658 	case (MOUNTCTL_SET_EXPORT):
1659 		tmp = (struct tmpfs_mount *) mp->mnt_data;
1660 
1661 		if (ap->a_ctllen != sizeof(struct export_args))
1662 			rc = (EINVAL);
1663 		else
1664 			rc = vfs_export(mp, &tmp->tm_export,
1665 					(const struct export_args *) ap->a_ctl);
1666 		break;
1667 	default:
1668 		rc = vop_stdmountctl(ap);
1669 		break;
1670 	}
1671 
1672 	lwkt_reltoken(&mp->mnt_token);
1673 	return (rc);
1674 }
1675 
1676 /* --------------------------------------------------------------------- */
1677 
1678 static int
1679 tmpfs_print(struct vop_print_args *v)
1680 {
1681 	struct vnode *vp = v->a_vp;
1682 
1683 	struct tmpfs_node *node;
1684 
1685 	node = VP_TO_TMPFS_NODE(vp);
1686 
1687 	kprintf("tag VT_TMPFS, tmpfs_node %p, flags 0x%x, links %d\n",
1688 	    node, node->tn_flags, node->tn_links);
1689 	kprintf("\tmode 0%o, owner %d, group %d, size %ju, status 0x%x\n",
1690 	    node->tn_mode, node->tn_uid, node->tn_gid,
1691 	    (uintmax_t)node->tn_size, node->tn_status);
1692 
1693 	if (vp->v_type == VFIFO)
1694 		fifo_printinfo(vp);
1695 
1696 	kprintf("\n");
1697 
1698 	return 0;
1699 }
1700 
1701 /* --------------------------------------------------------------------- */
1702 
1703 static int
1704 tmpfs_pathconf(struct vop_pathconf_args *v)
1705 {
1706 	int name = v->a_name;
1707 	register_t *retval = v->a_retval;
1708 
1709 	int error;
1710 
1711 	error = 0;
1712 
1713 	switch (name) {
1714 	case _PC_LINK_MAX:
1715 		*retval = LINK_MAX;
1716 		break;
1717 
1718 	case _PC_NAME_MAX:
1719 		*retval = NAME_MAX;
1720 		break;
1721 
1722 	case _PC_PATH_MAX:
1723 		*retval = PATH_MAX;
1724 		break;
1725 
1726 	case _PC_PIPE_BUF:
1727 		*retval = PIPE_BUF;
1728 		break;
1729 
1730 	case _PC_CHOWN_RESTRICTED:
1731 		*retval = 1;
1732 		break;
1733 
1734 	case _PC_NO_TRUNC:
1735 		*retval = 1;
1736 		break;
1737 
1738 	case _PC_SYNC_IO:
1739 		*retval = 1;
1740 		break;
1741 
1742 	case _PC_FILESIZEBITS:
1743 		*retval = 0; /* XXX Don't know which value should I return. */
1744 		break;
1745 
1746 	default:
1747 		error = EINVAL;
1748 	}
1749 
1750 	return error;
1751 }
1752 
1753 /************************************************************************
1754  *                          KQFILTER OPS                                *
1755  ************************************************************************/
1756 
1757 static void filt_tmpfsdetach(struct knote *kn);
1758 static int filt_tmpfsread(struct knote *kn, long hint);
1759 static int filt_tmpfswrite(struct knote *kn, long hint);
1760 static int filt_tmpfsvnode(struct knote *kn, long hint);
1761 
1762 static struct filterops tmpfsread_filtops =
1763 	{ FILTEROP_ISFD | FILTEROP_MPSAFE,
1764 	  NULL, filt_tmpfsdetach, filt_tmpfsread };
1765 static struct filterops tmpfswrite_filtops =
1766 	{ FILTEROP_ISFD | FILTEROP_MPSAFE,
1767 	  NULL, filt_tmpfsdetach, filt_tmpfswrite };
1768 static struct filterops tmpfsvnode_filtops =
1769 	{ FILTEROP_ISFD | FILTEROP_MPSAFE,
1770 	  NULL, filt_tmpfsdetach, filt_tmpfsvnode };
1771 
1772 static int
1773 tmpfs_kqfilter (struct vop_kqfilter_args *ap)
1774 {
1775 	struct vnode *vp = ap->a_vp;
1776 	struct knote *kn = ap->a_kn;
1777 
1778 	switch (kn->kn_filter) {
1779 	case EVFILT_READ:
1780 		kn->kn_fop = &tmpfsread_filtops;
1781 		break;
1782 	case EVFILT_WRITE:
1783 		kn->kn_fop = &tmpfswrite_filtops;
1784 		break;
1785 	case EVFILT_VNODE:
1786 		kn->kn_fop = &tmpfsvnode_filtops;
1787 		break;
1788 	default:
1789 		return (EOPNOTSUPP);
1790 	}
1791 
1792 	kn->kn_hook = (caddr_t)vp;
1793 
1794 	knote_insert(&vp->v_pollinfo.vpi_kqinfo.ki_note, kn);
1795 
1796 	return(0);
1797 }
1798 
1799 static void
1800 filt_tmpfsdetach(struct knote *kn)
1801 {
1802 	struct vnode *vp = (void *)kn->kn_hook;
1803 
1804 	knote_remove(&vp->v_pollinfo.vpi_kqinfo.ki_note, kn);
1805 }
1806 
1807 static int
1808 filt_tmpfsread(struct knote *kn, long hint)
1809 {
1810 	struct vnode *vp = (void *)kn->kn_hook;
1811 	struct tmpfs_node *node = VP_TO_TMPFS_NODE(vp);
1812 	off_t off;
1813 
1814 	if (hint == NOTE_REVOKE) {
1815 		kn->kn_flags |= (EV_EOF | EV_NODATA | EV_ONESHOT);
1816 		return(1);
1817 	}
1818 
1819 	/*
1820 	 * Interlock against MP races when performing this function.
1821 	 */
1822 	TMPFS_NODE_LOCK_SH(node);
1823 	off = node->tn_size - kn->kn_fp->f_offset;
1824 	kn->kn_data = (off < INTPTR_MAX) ? off : INTPTR_MAX;
1825 	if (kn->kn_sfflags & NOTE_OLDAPI) {
1826 		TMPFS_NODE_UNLOCK(node);
1827 		return(1);
1828 	}
1829 	if (kn->kn_data == 0) {
1830 		kn->kn_data = (off < INTPTR_MAX) ? off : INTPTR_MAX;
1831 	}
1832 	TMPFS_NODE_UNLOCK(node);
1833 	return (kn->kn_data != 0);
1834 }
1835 
1836 static int
1837 filt_tmpfswrite(struct knote *kn, long hint)
1838 {
1839 	if (hint == NOTE_REVOKE)
1840 		kn->kn_flags |= (EV_EOF | EV_NODATA | EV_ONESHOT);
1841 	kn->kn_data = 0;
1842 	return (1);
1843 }
1844 
1845 static int
1846 filt_tmpfsvnode(struct knote *kn, long hint)
1847 {
1848 	if (kn->kn_sfflags & hint)
1849 		kn->kn_fflags |= hint;
1850 	if (hint == NOTE_REVOKE) {
1851 		kn->kn_flags |= (EV_EOF | EV_NODATA);
1852 		return (1);
1853 	}
1854 	return (kn->kn_fflags != 0);
1855 }
1856 
1857 
1858 /* --------------------------------------------------------------------- */
1859 
1860 /*
1861  * vnode operations vector used for files stored in a tmpfs file system.
1862  */
1863 struct vop_ops tmpfs_vnode_vops = {
1864 	.vop_default =			vop_defaultop,
1865 	.vop_getpages = 		vop_stdgetpages,
1866 	.vop_putpages = 		vop_stdputpages,
1867 	.vop_ncreate =			tmpfs_ncreate,
1868 	.vop_nresolve =			tmpfs_nresolve,
1869 	.vop_nlookupdotdot =		tmpfs_nlookupdotdot,
1870 	.vop_nmknod =			tmpfs_nmknod,
1871 	.vop_open =			tmpfs_open,
1872 	.vop_close =			tmpfs_close,
1873 	.vop_access =			tmpfs_access,
1874 	.vop_getattr =			tmpfs_getattr,
1875 	.vop_setattr =			tmpfs_setattr,
1876 	.vop_read =			tmpfs_read,
1877 	.vop_write =			tmpfs_write,
1878 	.vop_fsync =			tmpfs_fsync,
1879 	.vop_mountctl =			tmpfs_mountctl,
1880 	.vop_nremove =			tmpfs_nremove,
1881 	.vop_nlink =			tmpfs_nlink,
1882 	.vop_nrename =			tmpfs_nrename,
1883 	.vop_nmkdir =			tmpfs_nmkdir,
1884 	.vop_nrmdir =			tmpfs_nrmdir,
1885 	.vop_nsymlink =			tmpfs_nsymlink,
1886 	.vop_readdir =			tmpfs_readdir,
1887 	.vop_readlink =			tmpfs_readlink,
1888 	.vop_inactive =			tmpfs_inactive,
1889 	.vop_reclaim =			tmpfs_reclaim,
1890 	.vop_print =			tmpfs_print,
1891 	.vop_pathconf =			tmpfs_pathconf,
1892 	.vop_bmap =			tmpfs_bmap,
1893 	.vop_strategy =			tmpfs_strategy,
1894 	.vop_advlock =			tmpfs_advlock,
1895 	.vop_kqfilter =			tmpfs_kqfilter
1896 };
1897