xref: /dragonfly/sys/vfs/tmpfs/tmpfs_vnops.c (revision 02fd838e)
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 *ap)
83 {
84 	struct vnode *dvp = ap->a_dvp;
85 	struct vnode *vp = NULL;
86 	struct namecache *ncp = ap->a_nch->ncp;
87 	struct tmpfs_node *tnode;
88 	struct tmpfs_dirent *de;
89 	struct tmpfs_node *dnode;
90 	int error;
91 
92 	dnode = VP_TO_TMPFS_DIR(dvp);
93 
94 	TMPFS_NODE_LOCK_SH(dnode);
95 	de = tmpfs_dir_lookup(dnode, NULL, ncp);
96 	if (de == NULL) {
97 		error = ENOENT;
98 	} else {
99 		/*
100 		 * Allocate a vnode for the node we found.
101 		 */
102 		tnode = de->td_node;
103 		error = tmpfs_alloc_vp(dvp->v_mount, tnode,
104 				       LK_EXCLUSIVE | LK_RETRY, &vp);
105 		if (error)
106 			goto out;
107 		KKASSERT(vp);
108 	}
109 
110 out:
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(ap->a_nch, vp);
127 		vrele(vp);
128 	} else if (error == ENOENT) {
129 		cache_setvp(ap->a_nch, NULL);
130 	}
131 	return (error);
132 }
133 
134 static int
135 tmpfs_nlookupdotdot(struct vop_nlookupdotdot_args *ap)
136 {
137 	struct vnode *dvp = ap->a_dvp;
138 	struct vnode **vpp = ap->a_vpp;
139 	struct tmpfs_node *dnode = VP_TO_TMPFS_NODE(dvp);
140 	struct ucred *cred = ap->a_cred;
141 	int error;
142 
143 	*vpp = NULL;
144 
145 	/* Check accessibility of requested node as a first step. */
146 	error = VOP_ACCESS(dvp, VEXEC, cred);
147 	if (error != 0)
148 		return error;
149 
150 	if (dnode->tn_dir.tn_parent != NULL) {
151 		/* Allocate a new vnode on the matching entry. */
152 		error = tmpfs_alloc_vp(dvp->v_mount, dnode->tn_dir.tn_parent,
153 				       LK_EXCLUSIVE | LK_RETRY, vpp);
154 
155 		if (*vpp)
156 			vn_unlock(*vpp);
157 	}
158 	return (*vpp == NULL) ? ENOENT : 0;
159 }
160 
161 /* --------------------------------------------------------------------- */
162 
163 static int
164 tmpfs_ncreate(struct vop_ncreate_args *ap)
165 {
166 	struct vnode *dvp = ap->a_dvp;
167 	struct vnode **vpp = ap->a_vpp;
168 	struct namecache *ncp = ap->a_nch->ncp;
169 	struct vattr *vap = ap->a_vap;
170 	struct ucred *cred = ap->a_cred;
171 	int error;
172 
173 	KKASSERT(vap->va_type == VREG || vap->va_type == VSOCK);
174 
175 	error = tmpfs_alloc_file(dvp, vpp, vap, ncp, cred, NULL);
176 	if (error == 0) {
177 		cache_setunresolved(ap->a_nch);
178 		cache_setvp(ap->a_nch, *vpp);
179 		tmpfs_knote(dvp, NOTE_WRITE);
180 	}
181 	return (error);
182 }
183 /* --------------------------------------------------------------------- */
184 
185 static int
186 tmpfs_nmknod(struct vop_nmknod_args *ap)
187 {
188 	struct vnode *dvp = ap->a_dvp;
189 	struct vnode **vpp = ap->a_vpp;
190 	struct namecache *ncp = ap->a_nch->ncp;
191 	struct vattr *vap = ap->a_vap;
192 	struct ucred *cred = ap->a_cred;
193 	int error;
194 
195 	if (vap->va_type != VBLK && vap->va_type != VCHR &&
196 	    vap->va_type != VFIFO) {
197 		return (EINVAL);
198 	}
199 
200 	error = tmpfs_alloc_file(dvp, vpp, vap, ncp, cred, NULL);
201 	if (error == 0) {
202 		cache_setunresolved(ap->a_nch);
203 		cache_setvp(ap->a_nch, *vpp);
204 		tmpfs_knote(dvp, NOTE_WRITE);
205 	}
206 	return error;
207 }
208 
209 /* --------------------------------------------------------------------- */
210 
211 static int
212 tmpfs_open(struct vop_open_args *ap)
213 {
214 	struct vnode *vp = ap->a_vp;
215 	int mode = ap->a_mode;
216 	struct tmpfs_node *node;
217 	int error;
218 
219 	node = VP_TO_TMPFS_NODE(vp);
220 
221 #if 0
222 	/* The file is still active but all its names have been removed
223 	 * (e.g. by a "rmdir $(pwd)").  It cannot be opened any more as
224 	 * it is about to die. */
225 	if (node->tn_links < 1)
226 		return (ENOENT);
227 #endif
228 
229 	/* If the file is marked append-only, deny write requests. */
230 	if ((node->tn_flags & APPEND) &&
231 	    (mode & (FWRITE | O_APPEND)) == FWRITE) {
232 		error = EPERM;
233 	} else {
234 		error = (vop_stdopen(ap));
235 	}
236 
237 	return (error);
238 }
239 
240 /* --------------------------------------------------------------------- */
241 
242 static int
243 tmpfs_close(struct vop_close_args *ap)
244 {
245 	struct vnode *vp = ap->a_vp;
246 	struct tmpfs_node *node;
247 	int error;
248 
249 	node = VP_TO_TMPFS_NODE(vp);
250 
251 	if (node->tn_links > 0) {
252 		/*
253 		 * Update node times.  No need to do it if the node has
254 		 * been deleted, because it will vanish after we return.
255 		 */
256 		tmpfs_update(vp);
257 	}
258 
259 	error = vop_stdclose(ap);
260 
261 	return (error);
262 }
263 
264 /* --------------------------------------------------------------------- */
265 
266 int
267 tmpfs_access(struct vop_access_args *ap)
268 {
269 	struct vnode *vp = ap->a_vp;
270 	int error;
271 	struct tmpfs_node *node;
272 
273 	node = VP_TO_TMPFS_NODE(vp);
274 
275 	switch (vp->v_type) {
276 	case VDIR:
277 		/* FALLTHROUGH */
278 	case VLNK:
279 		/* FALLTHROUGH */
280 	case VREG:
281 		if ((ap->a_mode & VWRITE) &&
282 	            (vp->v_mount->mnt_flag & MNT_RDONLY)) {
283 			error = EROFS;
284 			goto out;
285 		}
286 		break;
287 
288 	case VBLK:
289 		/* FALLTHROUGH */
290 	case VCHR:
291 		/* FALLTHROUGH */
292 	case VSOCK:
293 		/* FALLTHROUGH */
294 	case VFIFO:
295 		break;
296 
297 	default:
298 		error = EINVAL;
299 		goto out;
300 	}
301 
302 	if ((ap->a_mode & VWRITE) && (node->tn_flags & IMMUTABLE)) {
303 		error = EPERM;
304 		goto out;
305 	}
306 
307 	error = vop_helper_access(ap, node->tn_uid, node->tn_gid,
308 			          node->tn_mode, 0);
309 out:
310 	return error;
311 }
312 
313 /* --------------------------------------------------------------------- */
314 
315 int
316 tmpfs_getattr(struct vop_getattr_args *ap)
317 {
318 	struct vnode *vp = ap->a_vp;
319 	struct vattr *vap = ap->a_vap;
320 	struct tmpfs_node *node;
321 
322 	node = VP_TO_TMPFS_NODE(vp);
323 
324 	tmpfs_update(vp);
325 
326 	TMPFS_NODE_LOCK_SH(node);
327 	vap->va_type = vp->v_type;
328 	vap->va_mode = node->tn_mode;
329 	vap->va_nlink = node->tn_links;
330 	vap->va_uid = node->tn_uid;
331 	vap->va_gid = node->tn_gid;
332 	vap->va_fsid = vp->v_mount->mnt_stat.f_fsid.val[0];
333 	vap->va_fileid = node->tn_id;
334 	vap->va_size = node->tn_size;
335 	vap->va_blocksize = PAGE_SIZE;
336 	vap->va_atime.tv_sec = node->tn_atime;
337 	vap->va_atime.tv_nsec = node->tn_atimensec;
338 	vap->va_mtime.tv_sec = node->tn_mtime;
339 	vap->va_mtime.tv_nsec = node->tn_mtimensec;
340 	vap->va_ctime.tv_sec = node->tn_ctime;
341 	vap->va_ctime.tv_nsec = node->tn_ctimensec;
342 	vap->va_gen = node->tn_gen;
343 	vap->va_flags = node->tn_flags;
344 	if (vp->v_type == VBLK || vp->v_type == VCHR) {
345 		vap->va_rmajor = umajor(node->tn_rdev);
346 		vap->va_rminor = uminor(node->tn_rdev);
347 	}
348 	vap->va_bytes = round_page(node->tn_size);
349 	vap->va_filerev = 0;
350 	TMPFS_NODE_UNLOCK(node);
351 
352 	return 0;
353 }
354 
355 /* --------------------------------------------------------------------- */
356 
357 int
358 tmpfs_setattr(struct vop_setattr_args *ap)
359 {
360 	struct vnode *vp = ap->a_vp;
361 	struct vattr *vap = ap->a_vap;
362 	struct ucred *cred = ap->a_cred;
363 	struct tmpfs_node *node = VP_TO_TMPFS_NODE(vp);
364 	int error = 0;
365 	int kflags = 0;
366 
367 	TMPFS_NODE_LOCK(node);
368 	if (error == 0 && (vap->va_flags != VNOVAL)) {
369 		error = tmpfs_chflags(vp, vap->va_flags, cred);
370 		kflags |= NOTE_ATTRIB;
371 	}
372 
373 	if (error == 0 && (vap->va_size != VNOVAL)) {
374 		if (vap->va_size > node->tn_size)
375 			kflags |= NOTE_WRITE | NOTE_EXTEND;
376 		else
377 			kflags |= NOTE_WRITE;
378 		error = tmpfs_chsize(vp, vap->va_size, cred);
379 	}
380 
381 	if (error == 0 && (vap->va_uid != (uid_t)VNOVAL ||
382 			   vap->va_gid != (gid_t)VNOVAL)) {
383 		error = tmpfs_chown(vp, vap->va_uid, vap->va_gid, cred);
384 		kflags |= NOTE_ATTRIB;
385 	}
386 
387 	if (error == 0 && (vap->va_mode != (mode_t)VNOVAL)) {
388 		error = tmpfs_chmod(vp, vap->va_mode, cred);
389 		kflags |= NOTE_ATTRIB;
390 	}
391 
392 	if (error == 0 && ((vap->va_atime.tv_sec != VNOVAL &&
393 	    vap->va_atime.tv_nsec != VNOVAL) ||
394 	    (vap->va_mtime.tv_sec != VNOVAL &&
395 	    vap->va_mtime.tv_nsec != VNOVAL) )) {
396 		error = tmpfs_chtimes(vp, &vap->va_atime, &vap->va_mtime,
397 				      vap->va_vaflags, cred);
398 		kflags |= NOTE_ATTRIB;
399 	}
400 
401 	/*
402 	 * Update the node times.  We give preference to the error codes
403 	 * generated by this function rather than the ones that may arise
404 	 * from tmpfs_update.
405 	 */
406 	tmpfs_update(vp);
407 	TMPFS_NODE_UNLOCK(node);
408 	tmpfs_knote(vp, kflags);
409 
410 	return (error);
411 }
412 
413 /* --------------------------------------------------------------------- */
414 
415 /*
416  * fsync is usually a NOP, but we must take action when unmounting or
417  * when recycling.
418  */
419 static int
420 tmpfs_fsync(struct vop_fsync_args *ap)
421 {
422 	struct tmpfs_node *node;
423 	struct vnode *vp = ap->a_vp;
424 
425 	node = VP_TO_TMPFS_NODE(vp);
426 
427 	tmpfs_update(vp);
428 	if (vp->v_type == VREG) {
429 		if (vp->v_flag & VRECLAIMED) {
430 			if (node->tn_links == 0)
431 				tmpfs_truncate(vp, 0);
432 			else
433 				vfsync(ap->a_vp, ap->a_waitfor, 1, NULL, NULL);
434 		}
435 	}
436 	return 0;
437 }
438 
439 /* --------------------------------------------------------------------- */
440 
441 static int
442 tmpfs_read(struct vop_read_args *ap)
443 {
444 	struct buf *bp;
445 	struct vnode *vp = ap->a_vp;
446 	struct uio *uio = ap->a_uio;
447 	struct tmpfs_node *node;
448 	off_t base_offset;
449 	size_t offset;
450 	size_t len;
451 	size_t resid;
452 	int error;
453 
454 	/*
455 	 * Check the basics
456 	 */
457 	if (uio->uio_offset < 0)
458 		return (EINVAL);
459 	if (vp->v_type != VREG)
460 		return (EINVAL);
461 
462 	/*
463 	 * Extract node, try to shortcut the operation through
464 	 * the VM page cache, allowing us to avoid buffer cache
465 	 * overheads.
466 	 */
467 	node = VP_TO_TMPFS_NODE(vp);
468         resid = uio->uio_resid;
469         error = vop_helper_read_shortcut(ap);
470         if (error)
471                 return error;
472         if (uio->uio_resid == 0) {
473 		if (resid)
474 			goto finished;
475 		return error;
476 	}
477 
478 	/*
479 	 * Fall-through to our normal read code.
480 	 */
481 	while (uio->uio_resid > 0 && uio->uio_offset < node->tn_size) {
482 		/*
483 		 * Use buffer cache I/O (via tmpfs_strategy)
484 		 */
485 		offset = (size_t)uio->uio_offset & TMPFS_BLKMASK64;
486 		base_offset = (off_t)uio->uio_offset - offset;
487 		bp = getcacheblk(vp, base_offset, TMPFS_BLKSIZE, GETBLK_KVABIO);
488 		if (bp == NULL) {
489 			error = bread_kvabio(vp, base_offset,
490 					     TMPFS_BLKSIZE, &bp);
491 			if (error) {
492 				brelse(bp);
493 				kprintf("tmpfs_read bread error %d\n", error);
494 				break;
495 			}
496 
497 			/*
498 			 * tmpfs pretty much fiddles directly with the VM
499 			 * system, don't let it exhaust it or we won't play
500 			 * nice with other processes.
501 			 *
502 			 * Only do this if the VOP is coming from a normal
503 			 * read/write.  The VM system handles the case for
504 			 * UIO_NOCOPY.
505 			 */
506 			if (uio->uio_segflg != UIO_NOCOPY)
507 				vm_wait_nominal();
508 		}
509 		bp->b_flags |= B_CLUSTEROK;
510 		bkvasync(bp);
511 
512 		/*
513 		 * Figure out how many bytes we can actually copy this loop.
514 		 */
515 		len = TMPFS_BLKSIZE - offset;
516 		if (len > uio->uio_resid)
517 			len = uio->uio_resid;
518 		if (len > node->tn_size - uio->uio_offset)
519 			len = (size_t)(node->tn_size - uio->uio_offset);
520 
521 		error = uiomovebp(bp, (char *)bp->b_data + offset, len, uio);
522 		bqrelse(bp);
523 		if (error) {
524 			kprintf("tmpfs_read uiomove error %d\n", error);
525 			break;
526 		}
527 	}
528 
529 finished:
530 	if ((node->tn_status & TMPFS_NODE_ACCESSED) == 0) {
531 		TMPFS_NODE_LOCK(node);
532 		node->tn_status |= TMPFS_NODE_ACCESSED;
533 		TMPFS_NODE_UNLOCK(node);
534 	}
535 	return (error);
536 }
537 
538 static int
539 tmpfs_write(struct vop_write_args *ap)
540 {
541 	struct buf *bp;
542 	struct vnode *vp = ap->a_vp;
543 	struct uio *uio = ap->a_uio;
544 	struct thread *td = uio->uio_td;
545 	struct tmpfs_node *node;
546 	boolean_t extended;
547 	off_t oldsize;
548 	int error;
549 	off_t base_offset;
550 	size_t offset;
551 	size_t len;
552 	struct rlimit limit;
553 	int trivial = 0;
554 	int kflags = 0;
555 	int seqcount;
556 
557 	error = 0;
558 	if (uio->uio_resid == 0) {
559 		return error;
560 	}
561 
562 	node = VP_TO_TMPFS_NODE(vp);
563 
564 	if (vp->v_type != VREG)
565 		return (EINVAL);
566 	seqcount = ap->a_ioflag >> 16;
567 
568 	TMPFS_NODE_LOCK(node);
569 
570 	oldsize = node->tn_size;
571 	if (ap->a_ioflag & IO_APPEND)
572 		uio->uio_offset = node->tn_size;
573 
574 	/*
575 	 * Check for illegal write offsets.
576 	 */
577 	if (uio->uio_offset + uio->uio_resid >
578 	  VFS_TO_TMPFS(vp->v_mount)->tm_maxfilesize) {
579 		error = EFBIG;
580 		goto done;
581 	}
582 
583 	/*
584 	 * NOTE: Ignore if UIO does not come from a user thread (e.g. VN).
585 	 */
586 	if (vp->v_type == VREG && td != NULL && td->td_lwp != NULL) {
587 		error = kern_getrlimit(RLIMIT_FSIZE, &limit);
588 		if (error)
589 			goto done;
590 		if (uio->uio_offset + uio->uio_resid > limit.rlim_cur) {
591 			ksignal(td->td_proc, SIGXFSZ);
592 			error = EFBIG;
593 			goto done;
594 		}
595 	}
596 
597 	/*
598 	 * Extend the file's size if necessary
599 	 */
600 	extended = ((uio->uio_offset + uio->uio_resid) > node->tn_size);
601 
602 	while (uio->uio_resid > 0) {
603 		/*
604 		 * Don't completely blow out running buffer I/O
605 		 * when being hit from the pageout daemon.
606 		 */
607 		if (uio->uio_segflg == UIO_NOCOPY &&
608 		    (ap->a_ioflag & IO_RECURSE) == 0) {
609 			bwillwrite(TMPFS_BLKSIZE);
610 		}
611 
612 		/*
613 		 * Use buffer cache I/O (via tmpfs_strategy)
614 		 */
615 		offset = (size_t)uio->uio_offset & TMPFS_BLKMASK64;
616 		base_offset = (off_t)uio->uio_offset - offset;
617 		len = TMPFS_BLKSIZE - offset;
618 		if (len > uio->uio_resid)
619 			len = uio->uio_resid;
620 
621 		if ((uio->uio_offset + len) > node->tn_size) {
622 			trivial = (uio->uio_offset <= node->tn_size);
623 			error = tmpfs_reg_resize(vp, uio->uio_offset + len,
624 						 trivial);
625 			if (error)
626 				break;
627 		}
628 
629 		/*
630 		 * Read to fill in any gaps.  Theoretically we could
631 		 * optimize this if the write covers the entire buffer
632 		 * and is not a UIO_NOCOPY write, however this can lead
633 		 * to a security violation exposing random kernel memory
634 		 * (whatever junk was in the backing VM pages before).
635 		 *
636 		 * So just use bread() to do the right thing.
637 		 */
638 		error = bread_kvabio(vp, base_offset, TMPFS_BLKSIZE, &bp);
639 		bkvasync(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 	if (uio->uio_segflg != UIO_NOCOPY)
746 		node->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED;
747 	if (extended)
748 		node->tn_status |= TMPFS_NODE_CHANGED;
749 
750 	if (node->tn_mode & (S_ISUID | S_ISGID)) {
751 		if (priv_check_cred(ap->a_cred, PRIV_VFS_RETAINSUGID, 0))
752 			node->tn_mode &= ~(S_ISUID | S_ISGID);
753 	}
754 done:
755 	TMPFS_NODE_UNLOCK(node);
756 	if (kflags)
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  * We set VKVABIO for VREG files so bp->b_data may not be synchronized to
782  * our cpu.  swap_pager_strategy() is all we really use, and it directly
783  * supports this.
784  */
785 static int
786 tmpfs_strategy(struct vop_strategy_args *ap)
787 {
788 	struct bio *bio = ap->a_bio;
789 	struct bio *nbio;
790 	struct buf *bp = bio->bio_buf;
791 	struct vnode *vp = ap->a_vp;
792 	struct tmpfs_node *node;
793 	vm_object_t uobj;
794 	vm_page_t m;
795 	int i;
796 
797 	if (vp->v_type != VREG) {
798 		bp->b_resid = bp->b_bcount;
799 		bp->b_flags |= B_ERROR | B_INVAL;
800 		bp->b_error = EINVAL;
801 		biodone(bio);
802 		return(0);
803 	}
804 
805 	node = VP_TO_TMPFS_NODE(vp);
806 
807 	uobj = node->tn_reg.tn_aobj;
808 
809 	/*
810 	 * Don't bother flushing to swap if there is no swap, just
811 	 * ensure that the pages are marked as needing a commit (still).
812 	 */
813 	if (bp->b_cmd == BUF_CMD_WRITE && vm_swap_size == 0) {
814 		for (i = 0; i < bp->b_xio.xio_npages; ++i) {
815 			m = bp->b_xio.xio_pages[i];
816 			vm_page_need_commit(m);
817 		}
818 		bp->b_resid = 0;
819 		bp->b_error = 0;
820 		biodone(bio);
821 	} else {
822 		nbio = push_bio(bio);
823 		nbio->bio_done = tmpfs_strategy_done;
824 		nbio->bio_offset = bio->bio_offset;
825 		swap_pager_strategy(uobj, nbio);
826 	}
827 	return 0;
828 }
829 
830 /*
831  * If we were unable to commit the pages to swap make sure they are marked
832  * as needing a commit (again).  If we were, clear the flag to allow the
833  * pages to be freed.
834  */
835 static void
836 tmpfs_strategy_done(struct bio *bio)
837 {
838 	struct buf *bp;
839 	vm_page_t m;
840 	int i;
841 
842 	bp = bio->bio_buf;
843 
844 	if (bp->b_flags & B_ERROR) {
845 		bp->b_flags &= ~B_ERROR;
846 		bp->b_error = 0;
847 		bp->b_resid = 0;
848 		for (i = 0; i < bp->b_xio.xio_npages; ++i) {
849 			m = bp->b_xio.xio_pages[i];
850 			vm_page_need_commit(m);
851 		}
852 	} else {
853 		for (i = 0; i < bp->b_xio.xio_npages; ++i) {
854 			m = bp->b_xio.xio_pages[i];
855 			vm_page_clear_commit(m);
856 		}
857 	}
858 	bio = pop_bio(bio);
859 	biodone(bio);
860 }
861 
862 static int
863 tmpfs_bmap(struct vop_bmap_args *ap)
864 {
865 	if (ap->a_doffsetp != NULL)
866 		*ap->a_doffsetp = ap->a_loffset;
867 	if (ap->a_runp != NULL)
868 		*ap->a_runp = 0;
869 	if (ap->a_runb != NULL)
870 		*ap->a_runb = 0;
871 
872 	return 0;
873 }
874 
875 /* --------------------------------------------------------------------- */
876 
877 static int
878 tmpfs_nremove(struct vop_nremove_args *ap)
879 {
880 	struct vnode *dvp = ap->a_dvp;
881 	struct namecache *ncp = ap->a_nch->ncp;
882 	struct vnode *vp;
883 	int error;
884 	struct tmpfs_dirent *de;
885 	struct tmpfs_mount *tmp;
886 	struct tmpfs_node *dnode;
887 	struct tmpfs_node *node;
888 
889 	/*
890 	 * We have to acquire the vp from ap->a_nch because we will likely
891 	 * unresolve the namecache entry, and a vrele/vput is needed to
892 	 * trigger the tmpfs_inactive/tmpfs_reclaim sequence.
893 	 *
894 	 * We have to use vget to clear any inactive state on the vnode,
895 	 * otherwise the vnode may remain inactive and thus tmpfs_inactive
896 	 * will not get called when we release it.
897 	 */
898 	error = cache_vget(ap->a_nch, ap->a_cred, LK_SHARED, &vp);
899 	KKASSERT(vp->v_mount == dvp->v_mount);
900 	KKASSERT(error == 0);
901 	vn_unlock(vp);
902 
903 	if (vp->v_type == VDIR) {
904 		error = EISDIR;
905 		goto out2;
906 	}
907 
908 	dnode = VP_TO_TMPFS_DIR(dvp);
909 	node = VP_TO_TMPFS_NODE(vp);
910 	tmp = VFS_TO_TMPFS(vp->v_mount);
911 
912 	TMPFS_NODE_LOCK(dnode);
913 	de = tmpfs_dir_lookup(dnode, node, ncp);
914 	if (de == NULL) {
915 		error = ENOENT;
916 		goto out;
917 	}
918 
919 	/* Files marked as immutable or append-only cannot be deleted. */
920 	if ((node->tn_flags & (IMMUTABLE | APPEND | NOUNLINK)) ||
921 	    (dnode->tn_flags & APPEND)) {
922 		error = EPERM;
923 		goto out;
924 	}
925 
926 	/* Remove the entry from the directory; as it is a file, we do not
927 	 * have to change the number of hard links of the directory. */
928 	tmpfs_dir_detach(dnode, de);
929 
930 	/* Free the directory entry we just deleted.  Note that the node
931 	 * referred by it will not be removed until the vnode is really
932 	 * reclaimed. */
933 	tmpfs_free_dirent(tmp, de);
934 
935 	if (node->tn_links > 0) {
936 	        TMPFS_NODE_LOCK(node);
937 		node->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED | \
938 	                TMPFS_NODE_MODIFIED;
939 	        TMPFS_NODE_UNLOCK(node);
940 	}
941 
942 	cache_unlink(ap->a_nch);
943 	tmpfs_knote(vp, NOTE_DELETE);
944 	error = 0;
945 
946 out:
947 	TMPFS_NODE_UNLOCK(dnode);
948 	if (error == 0)
949 		tmpfs_knote(dvp, NOTE_WRITE);
950 out2:
951 	vrele(vp);
952 
953 	return error;
954 }
955 
956 /* --------------------------------------------------------------------- */
957 
958 static int
959 tmpfs_nlink(struct vop_nlink_args *ap)
960 {
961 	struct vnode *dvp = ap->a_dvp;
962 	struct vnode *vp = ap->a_vp;
963 	struct namecache *ncp = ap->a_nch->ncp;
964 	struct tmpfs_dirent *de;
965 	struct tmpfs_node *node;
966 	struct tmpfs_node *dnode;
967 	int error;
968 
969 	KKASSERT(dvp != vp); /* XXX When can this be false? */
970 
971 	node = VP_TO_TMPFS_NODE(vp);
972 	dnode = VP_TO_TMPFS_NODE(dvp);
973 	TMPFS_NODE_LOCK(dnode);
974 
975 	/* XXX: Why aren't the following two tests done by the caller? */
976 
977 	/* Hard links of directories are forbidden. */
978 	if (vp->v_type == VDIR) {
979 		error = EPERM;
980 		goto out;
981 	}
982 
983 	/* Cannot create cross-device links. */
984 	if (dvp->v_mount != vp->v_mount) {
985 		error = EXDEV;
986 		goto out;
987 	}
988 
989 	/* Ensure that we do not overflow the maximum number of links imposed
990 	 * by the system. */
991 	KKASSERT(node->tn_links <= LINK_MAX);
992 	if (node->tn_links >= LINK_MAX) {
993 		error = EMLINK;
994 		goto out;
995 	}
996 
997 	/* We cannot create links of files marked immutable or append-only. */
998 	if (node->tn_flags & (IMMUTABLE | APPEND)) {
999 		error = EPERM;
1000 		goto out;
1001 	}
1002 
1003 	/* Allocate a new directory entry to represent the node. */
1004 	error = tmpfs_alloc_dirent(VFS_TO_TMPFS(vp->v_mount), node,
1005 				   ncp->nc_name, ncp->nc_nlen, &de);
1006 	if (error != 0)
1007 		goto out;
1008 
1009 	/* Insert the new directory entry into the appropriate directory. */
1010 	tmpfs_dir_attach(dnode, de);
1011 
1012 	/* vp link count has changed, so update node times. */
1013 
1014 	TMPFS_NODE_LOCK(node);
1015 	node->tn_status |= TMPFS_NODE_CHANGED;
1016 	TMPFS_NODE_UNLOCK(node);
1017 	tmpfs_update(vp);
1018 
1019 	tmpfs_knote(vp, NOTE_LINK);
1020 	cache_setunresolved(ap->a_nch);
1021 	cache_setvp(ap->a_nch, vp);
1022 	error = 0;
1023 
1024 out:
1025 	TMPFS_NODE_UNLOCK(dnode);
1026 	if (error == 0)
1027 		tmpfs_knote(dvp, NOTE_WRITE);
1028 	return error;
1029 }
1030 
1031 /* --------------------------------------------------------------------- */
1032 
1033 static int
1034 tmpfs_nrename(struct vop_nrename_args *ap)
1035 {
1036 	struct vnode *fdvp = ap->a_fdvp;
1037 	struct namecache *fncp = ap->a_fnch->ncp;
1038 	struct vnode *fvp = fncp->nc_vp;
1039 	struct vnode *tdvp = ap->a_tdvp;
1040 	struct namecache *tncp = ap->a_tnch->ncp;
1041 	struct vnode *tvp;
1042 	struct tmpfs_dirent *de, *tde;
1043 	struct tmpfs_mount *tmp;
1044 	struct tmpfs_node *fdnode;
1045 	struct tmpfs_node *fnode;
1046 	struct tmpfs_node *tnode;
1047 	struct tmpfs_node *tdnode;
1048 	char *newname;
1049 	char *oldname;
1050 	int error;
1051 
1052 	KKASSERT(fdvp->v_mount == fvp->v_mount);
1053 
1054 	/*
1055 	 * Because tvp can get overwritten we have to vget it instead of
1056 	 * just vref or use it, otherwise it's VINACTIVE flag may not get
1057 	 * cleared and the node won't get destroyed.
1058 	 */
1059 	error = cache_vget(ap->a_tnch, ap->a_cred, LK_SHARED, &tvp);
1060 	if (error == 0) {
1061 		tnode = VP_TO_TMPFS_NODE(tvp);
1062 		vn_unlock(tvp);
1063 	} else {
1064 		tnode = NULL;
1065 	}
1066 
1067 	/* Disallow cross-device renames.
1068 	 * XXX Why isn't this done by the caller? */
1069 	if (fvp->v_mount != tdvp->v_mount ||
1070 	    (tvp != NULL && fvp->v_mount != tvp->v_mount)) {
1071 		error = EXDEV;
1072 		goto out;
1073 	}
1074 
1075 	tmp = VFS_TO_TMPFS(tdvp->v_mount);
1076 	tdnode = VP_TO_TMPFS_DIR(tdvp);
1077 
1078 	/* If source and target are the same file, there is nothing to do. */
1079 	if (fvp == tvp) {
1080 		error = 0;
1081 		goto out;
1082 	}
1083 
1084 	fdnode = VP_TO_TMPFS_DIR(fdvp);
1085 	fnode = VP_TO_TMPFS_NODE(fvp);
1086 	TMPFS_NODE_LOCK(fdnode);
1087 	de = tmpfs_dir_lookup(fdnode, fnode, fncp);
1088 	TMPFS_NODE_UNLOCK(fdnode);	/* XXX depend on namecache lock */
1089 
1090 	/* Avoid manipulating '.' and '..' entries. */
1091 	if (de == NULL) {
1092 		error = ENOENT;
1093 		goto out_locked;
1094 	}
1095 	KKASSERT(de->td_node == fnode);
1096 
1097 	/*
1098 	 * If replacing an entry in the target directory and that entry
1099 	 * is a directory, it must be empty.
1100 	 *
1101 	 * Kern_rename gurantees the destination to be a directory
1102 	 * if the source is one (it does?).
1103 	 */
1104 	if (tvp != NULL) {
1105 		KKASSERT(tnode != NULL);
1106 
1107 		if ((tnode->tn_flags & (NOUNLINK | IMMUTABLE | APPEND)) ||
1108 		    (tdnode->tn_flags & (APPEND | IMMUTABLE))) {
1109 			error = EPERM;
1110 			goto out_locked;
1111 		}
1112 
1113 		if (fnode->tn_type == VDIR && tnode->tn_type == VDIR) {
1114 			if (tnode->tn_size > 0) {
1115 				error = ENOTEMPTY;
1116 				goto out_locked;
1117 			}
1118 		} else if (fnode->tn_type == VDIR && tnode->tn_type != VDIR) {
1119 			error = ENOTDIR;
1120 			goto out_locked;
1121 		} else if (fnode->tn_type != VDIR && tnode->tn_type == VDIR) {
1122 			error = EISDIR;
1123 			goto out_locked;
1124 		} else {
1125 			KKASSERT(fnode->tn_type != VDIR &&
1126 				tnode->tn_type != VDIR);
1127 		}
1128 	}
1129 
1130 	if ((fnode->tn_flags & (NOUNLINK | IMMUTABLE | APPEND)) ||
1131 	    (fdnode->tn_flags & (APPEND | IMMUTABLE))) {
1132 		error = EPERM;
1133 		goto out_locked;
1134 	}
1135 
1136 	/*
1137 	 * Ensure that we have enough memory to hold the new name, if it
1138 	 * has to be changed.
1139 	 */
1140 	if (fncp->nc_nlen != tncp->nc_nlen ||
1141 	    bcmp(fncp->nc_name, tncp->nc_name, fncp->nc_nlen) != 0) {
1142 		newname = kmalloc(tncp->nc_nlen + 1, tmp->tm_name_zone,
1143 				  M_WAITOK | M_NULLOK);
1144 		if (newname == NULL) {
1145 			error = ENOSPC;
1146 			goto out_locked;
1147 		}
1148 		bcopy(tncp->nc_name, newname, tncp->nc_nlen);
1149 		newname[tncp->nc_nlen] = '\0';
1150 	} else {
1151 		newname = NULL;
1152 	}
1153 
1154 	/*
1155 	 * Unlink entry from source directory.  Note that the kernel has
1156 	 * already checked for illegal recursion cases (renaming a directory
1157 	 * into a subdirectory of itself).
1158 	 */
1159 	if (fdnode != tdnode) {
1160 		tmpfs_dir_detach(fdnode, de);
1161 	} else {
1162 		/* XXX depend on namecache lock */
1163 		TMPFS_NODE_LOCK(fdnode);
1164 		KKASSERT(de == tmpfs_dir_lookup(fdnode, fnode, fncp));
1165 		RB_REMOVE(tmpfs_dirtree, &fdnode->tn_dir.tn_dirtree, de);
1166 		RB_REMOVE(tmpfs_dirtree_cookie,
1167 			  &fdnode->tn_dir.tn_cookietree, de);
1168 		TMPFS_NODE_UNLOCK(fdnode);
1169 	}
1170 
1171 	/*
1172 	 * Handle any name change.  Swap with newname, we will
1173 	 * deallocate it at the end.
1174 	 */
1175 	if (newname != NULL) {
1176 #if 0
1177 		TMPFS_NODE_LOCK(fnode);
1178 		fnode->tn_status |= TMPFS_NODE_CHANGED;
1179 		TMPFS_NODE_UNLOCK(fnode);
1180 #endif
1181 		oldname = de->td_name;
1182 		de->td_name = newname;
1183 		de->td_namelen = (uint16_t)tncp->nc_nlen;
1184 		newname = oldname;
1185 	}
1186 
1187 	/*
1188 	 * If we are overwriting an entry, we have to remove the old one
1189 	 * from the target directory.
1190 	 */
1191 	if (tvp != NULL) {
1192 		/* Remove the old entry from the target directory. */
1193 		TMPFS_NODE_LOCK(tdnode);
1194 		tde = tmpfs_dir_lookup(tdnode, tnode, tncp);
1195 		tmpfs_dir_detach(tdnode, tde);
1196 		TMPFS_NODE_UNLOCK(tdnode);
1197 		tmpfs_knote(tdnode->tn_vnode, NOTE_DELETE);
1198 
1199 		/*
1200 		 * Free the directory entry we just deleted.  Note that the
1201 		 * node referred by it will not be removed until the vnode is
1202 		 * really reclaimed.
1203 		 */
1204 		tmpfs_free_dirent(VFS_TO_TMPFS(tvp->v_mount), tde);
1205 		/*cache_inval_vp(tvp, CINV_DESTROY);*/
1206 	}
1207 
1208 	/*
1209 	 * Link entry to target directory.  If the entry
1210 	 * represents a directory move the parent linkage
1211 	 * as well.
1212 	 */
1213 	if (fdnode != tdnode) {
1214 		if (de->td_node->tn_type == VDIR) {
1215 			TMPFS_VALIDATE_DIR(fnode);
1216 		}
1217 		tmpfs_dir_attach(tdnode, de);
1218 	} else {
1219 		TMPFS_NODE_LOCK(tdnode);
1220 		tdnode->tn_status |= TMPFS_NODE_MODIFIED;
1221 		RB_INSERT(tmpfs_dirtree, &tdnode->tn_dir.tn_dirtree, de);
1222 		RB_INSERT(tmpfs_dirtree_cookie,
1223 			  &tdnode->tn_dir.tn_cookietree, de);
1224 		TMPFS_NODE_UNLOCK(tdnode);
1225 	}
1226 
1227 	/*
1228 	 * Finish up
1229 	 */
1230 	if (newname) {
1231 		kfree(newname, tmp->tm_name_zone);
1232 		newname = NULL;
1233 	}
1234 	cache_rename(ap->a_fnch, ap->a_tnch);
1235 	tmpfs_knote(ap->a_fdvp, NOTE_WRITE);
1236 	tmpfs_knote(ap->a_tdvp, NOTE_WRITE);
1237 	if (fnode->tn_vnode)
1238 		tmpfs_knote(fnode->tn_vnode, NOTE_RENAME);
1239 	error = 0;
1240 
1241 out_locked:
1242 	;
1243 out:
1244 	if (tvp)
1245 		vrele(tvp);
1246 	return error;
1247 }
1248 
1249 /* --------------------------------------------------------------------- */
1250 
1251 static int
1252 tmpfs_nmkdir(struct vop_nmkdir_args *ap)
1253 {
1254 	struct vnode *dvp = ap->a_dvp;
1255 	struct vnode **vpp = ap->a_vpp;
1256 	struct namecache *ncp = ap->a_nch->ncp;
1257 	struct vattr *vap = ap->a_vap;
1258 	struct ucred *cred = ap->a_cred;
1259 	int error;
1260 
1261 	KKASSERT(vap->va_type == VDIR);
1262 
1263 	error = tmpfs_alloc_file(dvp, vpp, vap, ncp, cred, NULL);
1264 	if (error == 0) {
1265 		cache_setunresolved(ap->a_nch);
1266 		cache_setvp(ap->a_nch, *vpp);
1267 		tmpfs_knote(dvp, NOTE_WRITE | NOTE_LINK);
1268 	}
1269 	return error;
1270 }
1271 
1272 /* --------------------------------------------------------------------- */
1273 
1274 static int
1275 tmpfs_nrmdir(struct vop_nrmdir_args *ap)
1276 {
1277 	struct vnode *dvp = ap->a_dvp;
1278 	struct namecache *ncp = ap->a_nch->ncp;
1279 	struct vnode *vp;
1280 	struct tmpfs_dirent *de;
1281 	struct tmpfs_mount *tmp;
1282 	struct tmpfs_node *dnode;
1283 	struct tmpfs_node *node;
1284 	int error;
1285 
1286 	/*
1287 	 * We have to acquire the vp from ap->a_nch because we will likely
1288 	 * unresolve the namecache entry, and a vrele/vput is needed to
1289 	 * trigger the tmpfs_inactive/tmpfs_reclaim sequence.
1290 	 *
1291 	 * We have to use vget to clear any inactive state on the vnode,
1292 	 * otherwise the vnode may remain inactive and thus tmpfs_inactive
1293 	 * will not get called when we release it.
1294 	 */
1295 	error = cache_vget(ap->a_nch, ap->a_cred, LK_SHARED, &vp);
1296 	KKASSERT(error == 0);
1297 	vn_unlock(vp);
1298 
1299 	/*
1300 	 * Prevalidate so we don't hit an assertion later
1301 	 */
1302 	if (vp->v_type != VDIR) {
1303 		error = ENOTDIR;
1304 		goto out;
1305 	}
1306 
1307 	tmp = VFS_TO_TMPFS(dvp->v_mount);
1308 	dnode = VP_TO_TMPFS_DIR(dvp);
1309 	node = VP_TO_TMPFS_DIR(vp);
1310 
1311 	/*
1312 	 * Directories with more than two entries ('.' and '..') cannot
1313 	 * be removed.
1314 	 */
1315 	if (node->tn_size > 0) {
1316 		error = ENOTEMPTY;
1317 		goto out;
1318 	}
1319 
1320 	if ((dnode->tn_flags & APPEND)
1321 	    || (node->tn_flags & (NOUNLINK | IMMUTABLE | APPEND))) {
1322 		error = EPERM;
1323 		goto out;
1324 	}
1325 
1326 	/*
1327 	 * This invariant holds only if we are not trying to
1328 	 * remove "..".  We checked for that above so this is safe now.
1329 	 */
1330 	KKASSERT(node->tn_dir.tn_parent == dnode);
1331 
1332 	/*
1333 	 * Get the directory entry associated with node (vp).  This
1334 	 * was filled by tmpfs_lookup while looking up the entry.
1335 	 */
1336 	TMPFS_NODE_LOCK(dnode);
1337 	de = tmpfs_dir_lookup(dnode, node, ncp);
1338 	KKASSERT(TMPFS_DIRENT_MATCHES(de, ncp->nc_name, ncp->nc_nlen));
1339 
1340 	/* Check flags to see if we are allowed to remove the directory. */
1341 	if ((dnode->tn_flags & APPEND) ||
1342 	    node->tn_flags & (NOUNLINK | IMMUTABLE | APPEND)) {
1343 		error = EPERM;
1344 		TMPFS_NODE_UNLOCK(dnode);
1345 		goto out;
1346 	}
1347 
1348 	/* Detach the directory entry from the directory (dnode). */
1349 	tmpfs_dir_detach(dnode, de);
1350 	TMPFS_NODE_UNLOCK(dnode);
1351 
1352 	/* No vnode should be allocated for this entry from this point */
1353 	TMPFS_NODE_LOCK(dnode);
1354 	TMPFS_ASSERT_ELOCKED(dnode);
1355 	TMPFS_NODE_LOCK(node);
1356 	TMPFS_ASSERT_ELOCKED(node);
1357 
1358 	/*
1359 	 * Must set parent linkage to NULL (tested by ncreate to disallow
1360 	 * the creation of new files/dirs in a deleted directory)
1361 	 */
1362 	node->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED |
1363 			   TMPFS_NODE_MODIFIED;
1364 
1365 	dnode->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED |
1366 			    TMPFS_NODE_MODIFIED;
1367 
1368 	TMPFS_NODE_UNLOCK(node);
1369 	TMPFS_NODE_UNLOCK(dnode);
1370 
1371 	/* Free the directory entry we just deleted.  Note that the node
1372 	 * referred by it will not be removed until the vnode is really
1373 	 * reclaimed. */
1374 	tmpfs_free_dirent(tmp, de);
1375 
1376 	/* Release the deleted vnode (will destroy the node, notify
1377 	 * interested parties and clean it from the cache). */
1378 
1379 	TMPFS_NODE_LOCK(dnode);
1380 	dnode->tn_status |= TMPFS_NODE_CHANGED;
1381 	TMPFS_NODE_UNLOCK(dnode);
1382 	tmpfs_update(dvp);
1383 
1384 	cache_unlink(ap->a_nch);
1385 	tmpfs_knote(dvp, NOTE_WRITE | NOTE_LINK);
1386 	error = 0;
1387 
1388 out:
1389 	vrele(vp);
1390 
1391 	return error;
1392 }
1393 
1394 /* --------------------------------------------------------------------- */
1395 
1396 static int
1397 tmpfs_nsymlink(struct vop_nsymlink_args *ap)
1398 {
1399 	struct vnode *dvp = ap->a_dvp;
1400 	struct vnode **vpp = ap->a_vpp;
1401 	struct namecache *ncp = ap->a_nch->ncp;
1402 	struct vattr *vap = ap->a_vap;
1403 	struct ucred *cred = ap->a_cred;
1404 	char *target = ap->a_target;
1405 	int error;
1406 
1407 	vap->va_type = VLNK;
1408 	error = tmpfs_alloc_file(dvp, vpp, vap, ncp, cred, target);
1409 	if (error == 0) {
1410 		tmpfs_knote(*vpp, NOTE_WRITE);
1411 		cache_setunresolved(ap->a_nch);
1412 		cache_setvp(ap->a_nch, *vpp);
1413 	}
1414 	return error;
1415 }
1416 
1417 /* --------------------------------------------------------------------- */
1418 
1419 static int
1420 tmpfs_readdir(struct vop_readdir_args *ap)
1421 {
1422 	struct vnode *vp = ap->a_vp;
1423 	struct uio *uio = ap->a_uio;
1424 	int *eofflag = ap->a_eofflag;
1425 	off_t **cookies = ap->a_cookies;
1426 	int *ncookies = ap->a_ncookies;
1427 	struct tmpfs_mount *tmp;
1428 	int error;
1429 	off_t startoff;
1430 	off_t cnt = 0;
1431 	struct tmpfs_node *node;
1432 
1433 	/* This operation only makes sense on directory nodes. */
1434 	if (vp->v_type != VDIR) {
1435 		return ENOTDIR;
1436 	}
1437 
1438 	tmp = VFS_TO_TMPFS(vp->v_mount);
1439 	node = VP_TO_TMPFS_DIR(vp);
1440 	startoff = uio->uio_offset;
1441 
1442 	if (uio->uio_offset == TMPFS_DIRCOOKIE_DOT) {
1443 		error = tmpfs_dir_getdotdent(node, uio);
1444 		if (error != 0) {
1445 			TMPFS_NODE_LOCK_SH(node);
1446 			goto outok;
1447 		}
1448 		cnt++;
1449 	}
1450 
1451 	if (uio->uio_offset == TMPFS_DIRCOOKIE_DOTDOT) {
1452 		/* may lock parent, cannot hold node lock */
1453 		error = tmpfs_dir_getdotdotdent(tmp, node, uio);
1454 		if (error != 0) {
1455 			TMPFS_NODE_LOCK_SH(node);
1456 			goto outok;
1457 		}
1458 		cnt++;
1459 	}
1460 
1461 	TMPFS_NODE_LOCK_SH(node);
1462 	error = tmpfs_dir_getdents(node, uio, &cnt);
1463 
1464 outok:
1465 	KKASSERT(error >= -1);
1466 
1467 	if (error == -1)
1468 		error = 0;
1469 
1470 	if (eofflag != NULL)
1471 		*eofflag =
1472 		    (error == 0 && uio->uio_offset == TMPFS_DIRCOOKIE_EOF);
1473 
1474 	/* Update NFS-related variables. */
1475 	if (error == 0 && cookies != NULL && ncookies != NULL) {
1476 		off_t i;
1477 		off_t off = startoff;
1478 		struct tmpfs_dirent *de = NULL;
1479 
1480 		*ncookies = cnt;
1481 		*cookies = kmalloc(cnt * sizeof(off_t), M_TEMP, M_WAITOK);
1482 
1483 		for (i = 0; i < cnt; i++) {
1484 			KKASSERT(off != TMPFS_DIRCOOKIE_EOF);
1485 			if (off == TMPFS_DIRCOOKIE_DOT) {
1486 				off = TMPFS_DIRCOOKIE_DOTDOT;
1487 			} else {
1488 				if (off == TMPFS_DIRCOOKIE_DOTDOT) {
1489 					de = RB_MIN(tmpfs_dirtree_cookie,
1490 						&node->tn_dir.tn_cookietree);
1491 				} else if (de != NULL) {
1492 					de = RB_NEXT(tmpfs_dirtree_cookie,
1493 					       &node->tn_dir.tn_cookietree, de);
1494 				} else {
1495 					de = tmpfs_dir_lookupbycookie(node,
1496 								      off);
1497 					KKASSERT(de != NULL);
1498 					de = RB_NEXT(tmpfs_dirtree_cookie,
1499 					       &node->tn_dir.tn_cookietree, de);
1500 				}
1501 				if (de == NULL)
1502 					off = TMPFS_DIRCOOKIE_EOF;
1503 				else
1504 					off = tmpfs_dircookie(de);
1505 			}
1506 			(*cookies)[i] = off;
1507 		}
1508 		KKASSERT(uio->uio_offset == off);
1509 	}
1510 	TMPFS_NODE_UNLOCK(node);
1511 
1512 	if ((node->tn_status & TMPFS_NODE_ACCESSED) == 0) {
1513 		TMPFS_NODE_LOCK(node);
1514 		node->tn_status |= TMPFS_NODE_ACCESSED;
1515 		TMPFS_NODE_UNLOCK(node);
1516 	}
1517 	return error;
1518 }
1519 
1520 /* --------------------------------------------------------------------- */
1521 
1522 static int
1523 tmpfs_readlink(struct vop_readlink_args *ap)
1524 {
1525 	struct vnode *vp = ap->a_vp;
1526 	struct uio *uio = ap->a_uio;
1527 	int error;
1528 	struct tmpfs_node *node;
1529 
1530 	KKASSERT(uio->uio_offset == 0);
1531 	KKASSERT(vp->v_type == VLNK);
1532 
1533 	node = VP_TO_TMPFS_NODE(vp);
1534 	TMPFS_NODE_LOCK_SH(node);
1535 	error = uiomove(node->tn_link,
1536 			MIN(node->tn_size, uio->uio_resid), uio);
1537 	TMPFS_NODE_UNLOCK(node);
1538 	if ((node->tn_status & TMPFS_NODE_ACCESSED) == 0) {
1539 		TMPFS_NODE_LOCK(node);
1540 		node->tn_status |= TMPFS_NODE_ACCESSED;
1541 		TMPFS_NODE_UNLOCK(node);
1542 	}
1543 	return error;
1544 }
1545 
1546 /* --------------------------------------------------------------------- */
1547 
1548 static int
1549 tmpfs_inactive(struct vop_inactive_args *ap)
1550 {
1551 	struct vnode *vp = ap->a_vp;
1552 	struct tmpfs_node *node;
1553 	struct mount *mp;
1554 
1555 	mp = vp->v_mount;
1556 	lwkt_gettoken(&mp->mnt_token);
1557 	node = VP_TO_TMPFS_NODE(vp);
1558 
1559 	/*
1560 	 * Degenerate case
1561 	 */
1562 	if (node == NULL) {
1563 		vrecycle(vp);
1564 		lwkt_reltoken(&mp->mnt_token);
1565 		return(0);
1566 	}
1567 
1568 	/*
1569 	 * Get rid of unreferenced deleted vnodes sooner rather than
1570 	 * later so the data memory can be recovered immediately.
1571 	 *
1572 	 * We must truncate the vnode to prevent the normal reclamation
1573 	 * path from flushing the data for the removed file to disk.
1574 	 */
1575 	TMPFS_NODE_LOCK(node);
1576 	if ((node->tn_vpstate & TMPFS_VNODE_ALLOCATING) == 0 &&
1577 	    node->tn_links == 0)
1578 	{
1579 		node->tn_vpstate = TMPFS_VNODE_DOOMED;
1580 		TMPFS_NODE_UNLOCK(node);
1581 		if (node->tn_type == VREG)
1582 			tmpfs_truncate(vp, 0);
1583 		vrecycle(vp);
1584 	} else {
1585 		TMPFS_NODE_UNLOCK(node);
1586 	}
1587 	lwkt_reltoken(&mp->mnt_token);
1588 
1589 	return 0;
1590 }
1591 
1592 /* --------------------------------------------------------------------- */
1593 
1594 int
1595 tmpfs_reclaim(struct vop_reclaim_args *ap)
1596 {
1597 	struct vnode *vp = ap->a_vp;
1598 	struct tmpfs_mount *tmp;
1599 	struct tmpfs_node *node;
1600 	struct mount *mp;
1601 
1602 	mp = vp->v_mount;
1603 	lwkt_gettoken(&mp->mnt_token);
1604 
1605 	node = VP_TO_TMPFS_NODE(vp);
1606 	tmp = VFS_TO_TMPFS(vp->v_mount);
1607 	KKASSERT(mp == tmp->tm_mount);
1608 
1609 	tmpfs_free_vp(vp);
1610 
1611 	/*
1612 	 * If the node referenced by this vnode was deleted by the
1613 	 * user, we must free its associated data structures now that
1614 	 * the vnode is being reclaimed.
1615 	 *
1616 	 * Directories have an extra link ref.
1617 	 */
1618 	TMPFS_NODE_LOCK(node);
1619 	if ((node->tn_vpstate & TMPFS_VNODE_ALLOCATING) == 0 &&
1620 	    node->tn_links == 0) {
1621 		node->tn_vpstate = TMPFS_VNODE_DOOMED;
1622 		tmpfs_free_node(tmp, node);
1623 		/* eats the lock */
1624 	} else {
1625 		TMPFS_NODE_UNLOCK(node);
1626 	}
1627 	lwkt_reltoken(&mp->mnt_token);
1628 
1629 	KKASSERT(vp->v_data == NULL);
1630 	return 0;
1631 }
1632 
1633 /* --------------------------------------------------------------------- */
1634 
1635 static int
1636 tmpfs_mountctl(struct vop_mountctl_args *ap)
1637 {
1638 	struct tmpfs_mount *tmp;
1639 	struct mount *mp;
1640 	int rc;
1641 
1642 	mp = ap->a_head.a_ops->head.vv_mount;
1643 	lwkt_gettoken(&mp->mnt_token);
1644 
1645 	switch (ap->a_op) {
1646 	case (MOUNTCTL_SET_EXPORT):
1647 		tmp = (struct tmpfs_mount *) mp->mnt_data;
1648 
1649 		if (ap->a_ctllen != sizeof(struct export_args))
1650 			rc = (EINVAL);
1651 		else
1652 			rc = vfs_export(mp, &tmp->tm_export,
1653 					(const struct export_args *) ap->a_ctl);
1654 		break;
1655 	default:
1656 		rc = vop_stdmountctl(ap);
1657 		break;
1658 	}
1659 
1660 	lwkt_reltoken(&mp->mnt_token);
1661 	return (rc);
1662 }
1663 
1664 /* --------------------------------------------------------------------- */
1665 
1666 static int
1667 tmpfs_print(struct vop_print_args *ap)
1668 {
1669 	struct vnode *vp = ap->a_vp;
1670 
1671 	struct tmpfs_node *node;
1672 
1673 	node = VP_TO_TMPFS_NODE(vp);
1674 
1675 	kprintf("tag VT_TMPFS, tmpfs_node %p, flags 0x%x, links %d\n",
1676 	    node, node->tn_flags, node->tn_links);
1677 	kprintf("\tmode 0%o, owner %d, group %d, size %ju, status 0x%x\n",
1678 	    node->tn_mode, node->tn_uid, node->tn_gid,
1679 	    (uintmax_t)node->tn_size, node->tn_status);
1680 
1681 	if (vp->v_type == VFIFO)
1682 		fifo_printinfo(vp);
1683 
1684 	kprintf("\n");
1685 
1686 	return 0;
1687 }
1688 
1689 /* --------------------------------------------------------------------- */
1690 
1691 static int
1692 tmpfs_pathconf(struct vop_pathconf_args *ap)
1693 {
1694 	struct vnode *vp = ap->a_vp;
1695 	int name = ap->a_name;
1696 	register_t *retval = ap->a_retval;
1697 	struct tmpfs_mount *tmp;
1698 	int error;
1699 
1700 	error = 0;
1701 
1702 	switch (name) {
1703 	case _PC_CHOWN_RESTRICTED:
1704 		*retval = 1;
1705 		break;
1706 
1707 	case _PC_FILESIZEBITS:
1708 		tmp = VFS_TO_TMPFS(vp->v_mount);
1709 		*retval = max(32, flsll(tmp->tm_pages_max * PAGE_SIZE) + 1);
1710 		break;
1711 
1712 	case _PC_LINK_MAX:
1713 		*retval = LINK_MAX;
1714 		break;
1715 
1716 	case _PC_NAME_MAX:
1717 		*retval = NAME_MAX;
1718 		break;
1719 
1720 	case _PC_NO_TRUNC:
1721 		*retval = 1;
1722 		break;
1723 
1724 	case _PC_PATH_MAX:
1725 		*retval = PATH_MAX;
1726 		break;
1727 
1728 	case _PC_PIPE_BUF:
1729 		*retval = PIPE_BUF;
1730 		break;
1731 
1732 	case _PC_SYNC_IO:
1733 		*retval = 1;
1734 		break;
1735 
1736 	case _PC_2_SYMLINKS:
1737 		*retval = 1;
1738 		break;
1739 
1740 	default:
1741 		error = EINVAL;
1742 	}
1743 
1744 	return error;
1745 }
1746 
1747 /************************************************************************
1748  *                          KQFILTER OPS                                *
1749  ************************************************************************/
1750 
1751 static void filt_tmpfsdetach(struct knote *kn);
1752 static int filt_tmpfsread(struct knote *kn, long hint);
1753 static int filt_tmpfswrite(struct knote *kn, long hint);
1754 static int filt_tmpfsvnode(struct knote *kn, long hint);
1755 
1756 static struct filterops tmpfsread_filtops =
1757 	{ FILTEROP_ISFD | FILTEROP_MPSAFE,
1758 	  NULL, filt_tmpfsdetach, filt_tmpfsread };
1759 static struct filterops tmpfswrite_filtops =
1760 	{ FILTEROP_ISFD | FILTEROP_MPSAFE,
1761 	  NULL, filt_tmpfsdetach, filt_tmpfswrite };
1762 static struct filterops tmpfsvnode_filtops =
1763 	{ FILTEROP_ISFD | FILTEROP_MPSAFE,
1764 	  NULL, filt_tmpfsdetach, filt_tmpfsvnode };
1765 
1766 static int
1767 tmpfs_kqfilter (struct vop_kqfilter_args *ap)
1768 {
1769 	struct vnode *vp = ap->a_vp;
1770 	struct knote *kn = ap->a_kn;
1771 
1772 	switch (kn->kn_filter) {
1773 	case EVFILT_READ:
1774 		kn->kn_fop = &tmpfsread_filtops;
1775 		break;
1776 	case EVFILT_WRITE:
1777 		kn->kn_fop = &tmpfswrite_filtops;
1778 		break;
1779 	case EVFILT_VNODE:
1780 		kn->kn_fop = &tmpfsvnode_filtops;
1781 		break;
1782 	default:
1783 		return (EOPNOTSUPP);
1784 	}
1785 
1786 	kn->kn_hook = (caddr_t)vp;
1787 
1788 	knote_insert(&vp->v_pollinfo.vpi_kqinfo.ki_note, kn);
1789 
1790 	return(0);
1791 }
1792 
1793 static void
1794 filt_tmpfsdetach(struct knote *kn)
1795 {
1796 	struct vnode *vp = (void *)kn->kn_hook;
1797 
1798 	knote_remove(&vp->v_pollinfo.vpi_kqinfo.ki_note, kn);
1799 }
1800 
1801 static int
1802 filt_tmpfsread(struct knote *kn, long hint)
1803 {
1804 	struct vnode *vp = (void *)kn->kn_hook;
1805 	struct tmpfs_node *node = VP_TO_TMPFS_NODE(vp);
1806 	off_t off;
1807 
1808 	if (hint == NOTE_REVOKE) {
1809 		kn->kn_flags |= (EV_EOF | EV_NODATA | EV_ONESHOT);
1810 		return(1);
1811 	}
1812 
1813 	/*
1814 	 * Interlock against MP races when performing this function.
1815 	 */
1816 	TMPFS_NODE_LOCK_SH(node);
1817 	off = node->tn_size - kn->kn_fp->f_offset;
1818 	kn->kn_data = (off < INTPTR_MAX) ? off : INTPTR_MAX;
1819 	if (kn->kn_sfflags & NOTE_OLDAPI) {
1820 		TMPFS_NODE_UNLOCK(node);
1821 		return(1);
1822 	}
1823 	if (kn->kn_data == 0) {
1824 		kn->kn_data = (off < INTPTR_MAX) ? off : INTPTR_MAX;
1825 	}
1826 	TMPFS_NODE_UNLOCK(node);
1827 	return (kn->kn_data != 0);
1828 }
1829 
1830 static int
1831 filt_tmpfswrite(struct knote *kn, long hint)
1832 {
1833 	if (hint == NOTE_REVOKE)
1834 		kn->kn_flags |= (EV_EOF | EV_NODATA | EV_ONESHOT);
1835 	kn->kn_data = 0;
1836 	return (1);
1837 }
1838 
1839 static int
1840 filt_tmpfsvnode(struct knote *kn, long hint)
1841 {
1842 	if (kn->kn_sfflags & hint)
1843 		kn->kn_fflags |= hint;
1844 	if (hint == NOTE_REVOKE) {
1845 		kn->kn_flags |= (EV_EOF | EV_NODATA);
1846 		return (1);
1847 	}
1848 	return (kn->kn_fflags != 0);
1849 }
1850 
1851 
1852 /* --------------------------------------------------------------------- */
1853 
1854 /*
1855  * vnode operations vector used for files stored in a tmpfs file system.
1856  */
1857 struct vop_ops tmpfs_vnode_vops = {
1858 	.vop_default =			vop_defaultop,
1859 	.vop_getpages = 		vop_stdgetpages,
1860 	.vop_putpages = 		vop_stdputpages,
1861 	.vop_ncreate =			tmpfs_ncreate,
1862 	.vop_nresolve =			tmpfs_nresolve,
1863 	.vop_nlookupdotdot =		tmpfs_nlookupdotdot,
1864 	.vop_nmknod =			tmpfs_nmknod,
1865 	.vop_open =			tmpfs_open,
1866 	.vop_close =			tmpfs_close,
1867 	.vop_access =			tmpfs_access,
1868 	.vop_getattr =			tmpfs_getattr,
1869 	.vop_setattr =			tmpfs_setattr,
1870 	.vop_read =			tmpfs_read,
1871 	.vop_write =			tmpfs_write,
1872 	.vop_fsync =			tmpfs_fsync,
1873 	.vop_mountctl =			tmpfs_mountctl,
1874 	.vop_nremove =			tmpfs_nremove,
1875 	.vop_nlink =			tmpfs_nlink,
1876 	.vop_nrename =			tmpfs_nrename,
1877 	.vop_nmkdir =			tmpfs_nmkdir,
1878 	.vop_nrmdir =			tmpfs_nrmdir,
1879 	.vop_nsymlink =			tmpfs_nsymlink,
1880 	.vop_readdir =			tmpfs_readdir,
1881 	.vop_readlink =			tmpfs_readlink,
1882 	.vop_inactive =			tmpfs_inactive,
1883 	.vop_reclaim =			tmpfs_reclaim,
1884 	.vop_print =			tmpfs_print,
1885 	.vop_pathconf =			tmpfs_pathconf,
1886 	.vop_bmap =			tmpfs_bmap,
1887 	.vop_strategy =			tmpfs_strategy,
1888 	.vop_advlock =			tmpfs_advlock,
1889 	.vop_kqfilter =			tmpfs_kqfilter
1890 };
1891