Adjust some comments with reality.
[dragonfly.git] / sys / vfs / mfs / mfs_vnops.c
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1/*
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)mfs_vnops.c 8.11 (Berkeley) 5/22/95
34 * $FreeBSD: src/sys/ufs/mfs/mfs_vnops.c,v 1.47.2.1 2001/05/22 02:06:43 bp Exp $
b478fdce 35 * $DragonFly: src/sys/vfs/mfs/mfs_vnops.c,v 1.36 2007/08/08 00:12:51 swildner Exp $
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36 */
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/kernel.h>
41#include <sys/proc.h>
42#include <sys/buf.h>
43#include <sys/vnode.h>
44#include <sys/malloc.h>
45#include <sys/sysproto.h>
46#include <sys/mman.h>
47#include <sys/conf.h>
48
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49#include <vm/vm.h>
50#include <vm/vm_object.h>
51#include <vm/vm_page.h>
52#include <vm/vm_pager.h>
53#include <vm/vnode_pager.h>
3020e3be 54
d39c828b 55#include <sys/buf2.h>
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56#include <sys/thread2.h>
57
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58#include "mfsnode.h"
59#include "mfs_extern.h"
984263bc 60
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61static int mfs_badop (struct vop_generic_args *);
62static int mfs_bmap (struct vop_bmap_args *);
63static int mfs_close (struct vop_close_args *);
64static int mfs_fsync (struct vop_fsync_args *);
65static int mfs_freeblks (struct vop_freeblks_args *);
66static int mfs_inactive (struct vop_inactive_args *); /* XXX */
67static int mfs_open (struct vop_open_args *);
68static int mfs_reclaim (struct vop_reclaim_args *); /* XXX */
69static int mfs_print (struct vop_print_args *); /* XXX */
70static int mfs_strategy (struct vop_strategy_args *); /* XXX */
71static int mfs_getpages (struct vop_getpages_args *); /* XXX */
984263bc 72/*
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73 * mfs vnode operations. Note: the vops here are used for the MFS block
74 * device, not for operations on files (MFS calls the ffs mount code for that)
984263bc 75 */
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76static struct vop_ops mfs_vnode_vops = {
77 .vop_default = mfs_badop,
78 .vop_bmap = mfs_bmap,
79 .vop_close = mfs_close,
80 .vop_freeblks = mfs_freeblks,
81 .vop_fsync = mfs_fsync,
82 .vop_getpages = mfs_getpages,
83 .vop_inactive = mfs_inactive,
84 .vop_ioctl = (void *)vop_enotty,
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85 .vop_open = mfs_open,
86 .vop_print = mfs_print,
87 .vop_reclaim = mfs_reclaim,
88 .vop_strategy = mfs_strategy,
984263bc 89};
984263bc 90
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91struct vop_ops *mfs_vnode_vops_p = &mfs_vnode_vops;
92
93VNODEOP_SET(mfs_vnode_vops);
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94
95/*
96 * Vnode Operations.
97 *
98 * Open called to allow memory filesystem to initialize and
99 * validate before actual IO. Record our process identifier
100 * so we can tell when we are doing I/O to ourself.
77cf116b 101 *
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102 * NOTE: new device sequencing. mounts check the device reference count
103 * before calling open, so we must associate the device in open and
104 * disassociate it in close rather then faking it when we created the vnode.
105 *
77cf116b 106 * mfs_open(struct vnode *a_vp, int a_mode, struct ucred *a_cred,
b478fdce 107 * struct file *a_fp)
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108 */
109/* ARGSUSED */
110static int
77cf116b 111mfs_open(struct vop_open_args *ap)
984263bc 112{
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113 struct vnode *vp = ap->a_vp;
114
115 if (vp->v_type != VCHR)
0cbed593 116 panic("mfs_open not VCHR");
0e9b9130 117 v_associate_rdev(vp, get_dev(vp->v_umajor, vp->v_uminor));
8ddc6004 118 return (vop_stdopen(ap));
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119}
120
121static int
77cf116b 122mfs_fsync(struct vop_fsync_args *ap)
984263bc 123{
66a1ddf5 124 return (VOCALL(&spec_vnode_vops, &ap->a_head));
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125}
126
127/*
128 * mfs_freeblks() - hook to allow us to free physical memory.
129 *
10f3fee5 130 * We implement the BUF_CMD_FREEBLKS strategy. We can't just madvise()
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131 * here because we have to do it in the correct order vs other bio
132 * requests, so we queue it.
133 *
134 * Note: geteblk() sets B_INVAL. We leave it set to guarentee buffer
135 * throw-away on brelse()? XXX
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136 *
137 * mfs_freeblks(struct vnode *a_vp, daddr_t a_addr, daddr_t a_length)
984263bc 138 */
984263bc 139static int
77cf116b 140mfs_freeblks(struct vop_freeblks_args *ap)
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141{
142 struct buf *bp;
e4c9c0c8 143 struct vnode *vp = ap->a_vp;
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144
145 bp = geteblk(ap->a_length);
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146 bp->b_flags |= B_ASYNC;
147 bp->b_cmd = BUF_CMD_FREEBLKS;
54078292 148 bp->b_bio1.bio_offset = ap->a_offset;
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149 bp->b_bcount = ap->a_length;
150 BUF_KERNPROC(bp);
81b5c339 151 vn_strategy(vp, &bp->b_bio1);
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152 return(0);
153}
154
155/*
156 * Pass I/O requests to the memory filesystem process.
77cf116b 157 *
81b5c339 158 * mfs_strategy(struct vnode *a_vp, struct bio *a_bio)
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159 */
160static int
77cf116b 161mfs_strategy(struct vop_strategy_args *ap)
984263bc 162{
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163 struct bio *bio = ap->a_bio;
164 struct buf *bp = bio->bio_buf;
3ff2135f 165 struct mfsnode *mfsp;
dadab5e9 166 struct thread *td = curthread; /* XXX */
984263bc 167
81b5c339 168 mfsp = ap->a_vp->v_rdev->si_drv1;
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169 if (mfsp == NULL) {
170 bp->b_error = ENXIO;
171 bp->b_flags |= B_ERROR;
81b5c339 172 biodone(bio);
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173 return(0);
174 }
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175
176 /*
177 * splbio required for queueing/dequeueing, in case of forwarded
178 * BPs from bio interrupts (?). It may not be necessary.
179 */
180
165dba55 181 crit_enter();
984263bc 182
dadab5e9 183 if (mfsp->mfs_td == NULL) {
984263bc 184 /*
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185 * mini-root. Note: BUF_CMD_FREEBLKS not supported at the
186 * moment, since we do not know what kind of dataspace
187 * b_data is in.
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188 */
189 caddr_t base;
190
54078292 191 base = mfsp->mfs_baseoff + bio->bio_offset;
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192 switch(bp->b_cmd) {
193 case BUF_CMD_FREEBLKS:
194 break;
195 case BUF_CMD_READ:
984263bc 196 bcopy(base, bp->b_data, bp->b_bcount);
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197 break;
198 case BUF_CMD_WRITE:
984263bc 199 bcopy(bp->b_data, base, bp->b_bcount);
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200 break;
201 default:
202 panic("mfs: bad b_cmd %d\n", bp->b_cmd);
203 }
81b5c339 204 biodone(bio);
dadab5e9 205 } else if (mfsp->mfs_td == td) {
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206 /*
207 * VOP to self
208 */
165dba55 209 crit_exit();
81b5c339 210 mfs_doio(bio, mfsp);
165dba55 211 crit_enter();
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212 } else {
213 /*
214 * VOP from some other process, queue to MFS process and
215 * wake it up.
216 */
81b5c339 217 bioq_insert_tail(&mfsp->bio_queue, bio);
e4c9c0c8 218 wakeup((caddr_t)mfsp);
984263bc 219 }
165dba55 220 crit_exit();
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221 return (0);
222}
223
224/*
225 * Memory file system I/O.
226 *
227 * Trivial on the HP since buffer has already been mapping into KVA space.
228 *
229 * Read and Write are handled with a simple copyin and copyout.
230 *
10f3fee5 231 * We also partially support VOP_FREEBLKS(). We can't implement
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232 * completely -- for example, on fragments or inode metadata, but we can
233 * implement it for page-aligned requests.
234 */
235void
81b5c339 236mfs_doio(struct bio *bio, struct mfsnode *mfsp)
984263bc 237{
81b5c339 238 struct buf *bp = bio->bio_buf;
54078292 239 caddr_t base = mfsp->mfs_baseoff + bio->bio_offset;
10f3fee5 240 int bytes;
984263bc 241
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242 switch(bp->b_cmd) {
243 case BUF_CMD_FREEBLKS:
984263bc 244 /*
10f3fee5 245 * Implement FREEBLKS, which allows the filesystem to tell
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246 * a block device when blocks are no longer needed (like when
247 * a file is deleted). We use the hook to MADV_FREE the VM.
248 * This makes an MFS filesystem work as well or better then
249 * a sun-style swap-mounted filesystem.
250 */
10f3fee5 251 bytes = bp->b_bcount;
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252
253 if ((vm_offset_t)base & PAGE_MASK) {
254 int n = PAGE_SIZE - ((vm_offset_t)base & PAGE_MASK);
255 bytes -= n;
256 base += n;
257 }
258 if (bytes > 0) {
259 struct madvise_args uap;
260
261 bytes &= ~PAGE_MASK;
262 if (bytes != 0) {
263 bzero(&uap, sizeof(uap));
264 uap.addr = base;
265 uap.len = bytes;
266 uap.behav = MADV_FREE;
753fd850 267 sys_madvise(&uap);
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268 }
269 }
270 bp->b_error = 0;
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271 break;
272 case BUF_CMD_READ:
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273 /*
274 * Read data from our 'memory' disk
275 */
276 bp->b_error = copyin(base, bp->b_data, bp->b_bcount);
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277 break;
278 case BUF_CMD_WRITE:
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279 /*
280 * Write data to our 'memory' disk
281 */
282 bp->b_error = copyout(bp->b_data, base, bp->b_bcount);
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283 break;
284 default:
285 panic("mfs: bad b_cmd %d\n", bp->b_cmd);
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286 }
287 if (bp->b_error)
288 bp->b_flags |= B_ERROR;
81b5c339 289 biodone(bio);
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290}
291
292/*
293 * This is a noop, simply returning what one has been given.
77cf116b 294 *
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295 * mfs_bmap(struct vnode *a_vp, off_t a_loffset, struct vnode **a_vpp,
296 * off_t *a_doffsetp, int *a_runp, int *a_runb)
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297 */
298static int
77cf116b 299mfs_bmap(struct vop_bmap_args *ap)
984263bc 300{
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301 if (ap->a_vpp != NULL)
302 *ap->a_vpp = ap->a_vp;
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303 if (ap->a_doffsetp != NULL)
304 *ap->a_doffsetp = ap->a_loffset;
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305 if (ap->a_runp != NULL)
306 *ap->a_runp = 0;
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307 if (ap->a_runb != NULL)
308 *ap->a_runb = 0;
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309 return (0);
310}
311
312/*
313 * Memory filesystem close routine
77cf116b 314 *
b478fdce 315 * mfs_close(struct vnode *a_vp, int a_fflag)
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316 */
317/* ARGSUSED */
318static int
77cf116b 319mfs_close(struct vop_close_args *ap)
984263bc 320{
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321 struct vnode *vp = ap->a_vp;
322 struct mfsnode *mfsp = VTOMFS(vp);
81b5c339 323 struct bio *bio;
d39c828b 324 int error = 0;
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325
326 /*
327 * Finish any pending I/O requests.
328 */
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329 while ((bio = bioq_first(&mfsp->bio_queue)) != NULL) {
330 bioq_remove(&mfsp->bio_queue, bio);
331 mfs_doio(bio, mfsp);
332 wakeup((caddr_t)bio->bio_buf);
984263bc 333 }
d39c828b 334
984263bc 335 /*
d39c828b 336 * We really only care about the last close
984263bc 337 */
d39c828b 338 if (vp->v_opencount > 1)
8ddc6004 339 goto done;
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340
341 /*
342 * Synchronize any remaining buffers and then destroy them.
343 */
87de5057 344 if ((error = vinvalbuf(vp, V_SAVE, 0, 0)) != 0)
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345 goto done;
346
347 /*
348 * Get rid of the pseudo-backing object. Since the object is
349 * not directly memory mapped, we don't have to worry about
350 * synchronizing it.
351 */
352 if (vp->v_object)
353 vm_pager_deallocate(vp->v_object);
354
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355 /*
356 * There should be no way to have any more uses of this
357 * vnode, so if we find any other uses, it is a panic.
358 */
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359 if (vp->v_sysref.refcnt > 1)
360 kprintf("mfs_close: ref count %d > 1\n", vp->v_sysref.refcnt);
361 if (vp->v_sysref.refcnt > 1 || (bioq_first(&mfsp->bio_queue) != NULL))
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362 panic("mfs_close");
363 /*
364 * Send a request to the filesystem server to exit.
365 */
366 mfsp->mfs_active = 0;
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367 v_release_rdev(vp);
368 if (mfsp->mfs_dev) {
369 destroy_dev(mfsp->mfs_dev);
370 mfsp->mfs_dev = NULL;
371 }
372 wakeup((caddr_t)mfsp);
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373done:
374 vop_stdclose(ap);
375 return (error);
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376}
377
378/*
379 * Memory filesystem inactive routine
77cf116b 380 *
b478fdce 381 * mfs_inactive(struct vnode *a_vp)
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382 */
383/* ARGSUSED */
384static int
77cf116b 385mfs_inactive(struct vop_inactive_args *ap)
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386{
387 struct vnode *vp = ap->a_vp;
388 struct mfsnode *mfsp = VTOMFS(vp);
389
81b5c339 390 if (bioq_first(&mfsp->bio_queue) != NULL)
984263bc 391 panic("mfs_inactive: not inactive (next buffer %p)",
81b5c339 392 bioq_first(&mfsp->bio_queue));
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393 return (0);
394}
395
396/*
397 * Reclaim a memory filesystem devvp so that it can be reused.
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398 *
399 * mfs_reclaim(struct vnode *a_vp)
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400 */
401static int
77cf116b 402mfs_reclaim(struct vop_reclaim_args *ap)
984263bc 403{
3ff2135f 404 struct vnode *vp = ap->a_vp;
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405
406 FREE(vp->v_data, M_MFSNODE);
407 vp->v_data = NULL;
408 return (0);
409}
410
411/*
412 * Print out the contents of an mfsnode.
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413 *
414 * mfs_print(struct vnode *a_vp)
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415 */
416static int
77cf116b 417mfs_print(struct vop_print_args *ap)
984263bc 418{
3ff2135f 419 struct mfsnode *mfsp = VTOMFS(ap->a_vp);
984263bc 420
086c1d7e 421 kprintf("tag VT_MFS, td %p, base %p, size %ld\n",
dadab5e9 422 mfsp->mfs_td, (void *)mfsp->mfs_baseoff, mfsp->mfs_size);
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423 return (0);
424}
425
426/*
427 * Block device bad operation
428 */
429static int
430mfs_badop(struct vop_generic_args *ap)
431{
432 int i;
433
086c1d7e 434 kprintf("mfs_badop[%s]\n", ap->a_desc->sd_name);
984263bc 435 i = vop_defaultop(ap);
086c1d7e 436 kprintf("mfs_badop[%s] = %d\n", ap->a_desc->sd_name, i);
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437 return (i);
438}
439
984263bc 440static int
77cf116b 441mfs_getpages(struct vop_getpages_args *ap)
984263bc 442{
66a1ddf5 443 return (VOCALL(&spec_vnode_vops, &ap->a_head));
984263bc 444}