2 * Copyright (c) 1988 University of Utah.
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
6 * This code is derived from software contributed to Berkeley by
7 * the Systems Programming Group of the University of Utah Computer
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * from: Utah Hdr: vn.c 1.13 94/04/02
40 * from: @(#)vn.c 8.6 (Berkeley) 4/1/94
41 * $FreeBSD: src/sys/dev/vn/vn.c,v 1.105.2.4 2001/11/18 07:11:00 dillon Exp $
42 * $DragonFly: src/sys/dev/disk/vn/vn.c,v 1.19 2006/04/30 17:22:16 dillon Exp $
48 * Block/character interface to a vnode. Allows one to treat a file
49 * as a disk (e.g. build a filesystem in it, mount it, etc.).
51 * NOTE 1: There is a security issue involved with this driver.
52 * Once mounted all access to the contents of the "mapped" file via
53 * the special file is controlled by the permissions on the special
54 * file, the protection of the mapped file is ignored (effectively,
55 * by using root credentials in all transactions).
57 * NOTE 2: Doesn't interact with leases, should it?
60 #include <sys/param.h>
61 #include <sys/systm.h>
62 #include <sys/kernel.h>
64 #include <sys/nlookup.h>
66 #include <sys/malloc.h>
67 #include <sys/mount.h>
68 #include <sys/vnode.h>
69 #include <sys/fcntl.h>
71 #include <sys/disklabel.h>
72 #include <sys/diskslice.h>
74 #include <sys/module.h>
75 #include <sys/vnioctl.h>
78 #include <vm/vm_object.h>
79 #include <vm/vm_page.h>
80 #include <vm/vm_pager.h>
81 #include <vm/vm_pageout.h>
82 #include <vm/swap_pager.h>
83 #include <vm/vm_extern.h>
84 #include <vm/vm_zone.h>
86 static d_ioctl_t vnioctl;
87 static d_open_t vnopen;
88 static d_close_t vnclose;
89 static d_psize_t vnsize;
90 static d_strategy_t vnstrategy;
94 #define VN_BSIZE_BEST 8192
98 * D_DISK we want to look like a disk
99 * D_CANFREE We support BUF_CMD_FREEBLKS
102 static struct cdevsw vn_cdevsw = {
104 /* maj */ CDEV_MAJOR,
105 /* flags */ D_DISK|D_CANFREE,
112 /* write */ physwrite,
116 /* strategy */ vnstrategy,
123 int sc_flags; /* flags */
124 int sc_size; /* size of vn, sc_secsize scale */
125 int sc_secsize; /* sector size */
126 struct diskslices *sc_slices;
127 struct vnode *sc_vp; /* vnode if not NULL */
128 vm_object_t sc_object; /* backing object if not NULL */
129 struct ucred *sc_cred; /* credentials */
130 int sc_maxactive; /* max # of active requests */
131 struct buf sc_tab; /* transfer queue */
132 u_long sc_options; /* options */
133 dev_t sc_devlist; /* devices that refer to this unit */
134 SLIST_ENTRY(vn_softc) sc_list;
137 static SLIST_HEAD(, vn_softc) vn_list;
140 #define VNF_INITED 0x01
141 #define VNF_READONLY 0x02
143 static u_long vn_options;
145 #define IFOPT(vn,opt) if (((vn)->sc_options|vn_options) & (opt))
146 #define TESTOPT(vn,opt) (((vn)->sc_options|vn_options) & (opt))
148 static int vnsetcred (struct vn_softc *vn, struct ucred *cred);
149 static void vnclear (struct vn_softc *vn);
150 static int vn_modevent (module_t, int, void *);
151 static int vniocattach_file (struct vn_softc *, struct vn_ioctl *, dev_t dev, int flag, struct thread *p);
152 static int vniocattach_swap (struct vn_softc *, struct vn_ioctl *, dev_t dev, int flag, struct thread *p);
155 vnclose(dev_t dev, int flags, int mode, struct thread *td)
157 struct vn_softc *vn = dev->si_drv1;
160 if (vn->sc_slices != NULL)
161 dsclose(dev, mode, vn->sc_slices);
166 * Called only when si_drv1 is NULL. Locate the associated vn node and
167 * attach the device to it.
169 static struct vn_softc *
176 SLIST_FOREACH(vn, &vn_list, sc_list) {
177 if (vn->sc_unit == unit) {
179 dev->si_drv2 = vn->sc_devlist;
180 vn->sc_devlist = dev;
186 vn = malloc(sizeof *vn, M_DEVBUF, M_WAITOK | M_ZERO);
189 vn->sc_devlist = make_dev(&vn_cdevsw, 0, UID_ROOT,
190 GID_OPERATOR, 0640, "vn%d", unit);
191 if (vn->sc_devlist->si_drv1 == NULL) {
192 reference_dev(vn->sc_devlist);
193 vn->sc_devlist->si_drv1 = vn;
194 vn->sc_devlist->si_drv2 = NULL;
196 if (vn->sc_devlist != dev) {
198 dev->si_drv2 = vn->sc_devlist;
199 vn->sc_devlist = dev;
202 SLIST_INSERT_HEAD(&vn_list, vn, sc_list);
208 vnopen(dev_t dev, int flags, int mode, struct thread *td)
213 * Locate preexisting device
216 if ((vn = dev->si_drv1) == NULL)
220 * Update si_bsize fields for device. This data will be overriden by
221 * the slice/parition code for vn accesses through partitions, and
222 * used directly if you open the 'whole disk' device.
224 * si_bsize_best must be reinitialized in case VN has been
225 * reconfigured, plus make it at least VN_BSIZE_BEST for efficiency.
227 dev->si_bsize_phys = vn->sc_secsize;
228 dev->si_bsize_best = vn->sc_secsize;
229 if (dev->si_bsize_best < VN_BSIZE_BEST)
230 dev->si_bsize_best = VN_BSIZE_BEST;
232 if ((flags & FWRITE) && (vn->sc_flags & VNF_READONLY))
236 printf("vnopen(%s, 0x%x, 0x%x, %p)\n",
237 devtoname(dev), flags, mode, (void *)td);
243 IFOPT(vn, VN_LABELS) {
244 if (vn->sc_flags & VNF_INITED) {
245 struct disklabel label;
247 /* Build label for whole disk. */
248 bzero(&label, sizeof label);
249 label.d_secsize = vn->sc_secsize;
250 label.d_nsectors = 32;
251 label.d_ntracks = 64 / (vn->sc_secsize / DEV_BSIZE);
252 label.d_secpercyl = label.d_nsectors * label.d_ntracks;
253 label.d_ncylinders = vn->sc_size / label.d_secpercyl;
254 label.d_secperunit = vn->sc_size;
255 label.d_partitions[RAW_PART].p_size = vn->sc_size;
257 return (dsopen(dev, mode, 0, &vn->sc_slices, &label));
259 if (dkslice(dev) != WHOLE_DISK_SLICE ||
260 dkpart(dev) != RAW_PART ||
271 * Run strategy routine for VN device. We use VOP_READ/VOP_WRITE calls
272 * for vnode-backed vn's, and the new vm_pager_strategy() call for
273 * vm_object-backed vn's.
275 * Currently B_ASYNC is only partially handled - for OBJT_SWAP I/O only.
279 vnstrategy(dev_t dev, struct bio *bio)
288 if ((vn = dev->si_drv1) == NULL)
294 printf("vnstrategy(%p): unit %d\n", bp, unit);
296 if ((vn->sc_flags & VNF_INITED) == 0) {
298 bp->b_flags |= B_ERROR;
303 bp->b_resid = bp->b_bcount;
305 IFOPT(vn, VN_LABELS) {
307 * The vnode device is using disk/slice label support.
309 * The dscheck() function is called for validating the
310 * slices that exist ON the vnode device itself, and
311 * translate the "slice-relative" block number, again.
313 if (vn->sc_slices == NULL) {
315 } else if ((nbio = dscheck(dev, bio, vn->sc_slices)) == NULL) {
316 bp->b_flags |= B_INVAL;
321 int pbn; /* in sc_secsize chunks */
322 long sz; /* in sc_secsize chunks */
325 * Check for required alignment. Transfers must be a valid
326 * multiple of the sector size.
328 if (bp->b_bcount % vn->sc_secsize != 0 ||
329 bio->bio_offset % vn->sc_secsize != 0) {
330 bp->b_error = EINVAL;
331 bp->b_flags |= B_ERROR | B_INVAL;
336 pbn = bio->bio_offset / vn->sc_secsize;
337 sz = howmany(bp->b_bcount, vn->sc_secsize);
340 * If out of bounds return an error. If at the EOF point,
341 * simply read or write less.
343 if (pbn < 0 || pbn >= vn->sc_size) {
344 if (pbn != vn->sc_size) {
345 bp->b_error = EINVAL;
346 bp->b_flags |= B_ERROR | B_INVAL;
353 * If the request crosses EOF, truncate the request.
355 if (pbn + sz > vn->sc_size) {
356 bp->b_bcount = (vn->sc_size - pbn) * vn->sc_secsize;
357 bp->b_resid = bp->b_bcount;
359 nbio = push_bio(bio);
360 nbio->bio_offset = pbn * vn->sc_secsize;
364 * Use the translated nbio from this point on
366 if (vn->sc_vp && bp->b_cmd == BUF_CMD_FREEBLKS) {
368 * Freeblks is not handled for vnode-backed elements yet.
371 } else if (vn->sc_vp) {
375 * If an error occurs, we set B_ERROR but we do not set
376 * B_INVAL because (for a write anyway), the buffer is
382 bzero(&auio, sizeof(auio));
384 aiov.iov_base = bp->b_data;
385 aiov.iov_len = bp->b_bcount;
386 auio.uio_iov = &aiov;
388 auio.uio_offset = nbio->bio_offset;
389 auio.uio_segflg = UIO_SYSSPACE;
390 if (bp->b_cmd == BUF_CMD_READ)
391 auio.uio_rw = UIO_READ;
393 auio.uio_rw = UIO_WRITE;
394 auio.uio_resid = bp->b_bcount;
395 auio.uio_td = curthread;
396 vn_lock(vn->sc_vp, LK_EXCLUSIVE | LK_RETRY, curthread);
397 if (bp->b_cmd == BUF_CMD_READ)
398 error = VOP_READ(vn->sc_vp, &auio, IO_DIRECT, vn->sc_cred);
400 error = VOP_WRITE(vn->sc_vp, &auio, IO_NOWDRAIN, vn->sc_cred);
401 VOP_UNLOCK(vn->sc_vp, 0, curthread);
402 bp->b_resid = auio.uio_resid;
406 bp->b_flags |= B_ERROR;
409 } else if (vn->sc_object) {
413 * ( handles read, write, freebuf )
415 * Note: freeblks is not supported with pre-reserved swap.
417 KASSERT((bp->b_bufsize & (vn->sc_secsize - 1)) == 0,
418 ("vnstrategy: buffer %p too small for physio", bp));
420 if (bp->b_cmd == BUF_CMD_FREEBLKS && TESTOPT(vn, VN_RESERVE)) {
423 vm_pager_strategy(vn->sc_object, nbio);
426 bp->b_flags |= B_ERROR;
427 bp->b_error = EINVAL;
434 vnioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct thread *td)
437 struct vn_ioctl *vio;
443 printf("vnioctl(%s, 0x%lx, %p, 0x%x, %p): unit %d\n",
444 devtoname(dev), cmd, (void *)data, flag, (void *)td,
457 IFOPT(vn,VN_LABELS) {
458 if (vn->sc_slices != NULL) {
459 error = dsioctl(dev, cmd, data, flag, &vn->sc_slices);
460 if (error != ENOIOCTL)
463 if (dkslice(dev) != WHOLE_DISK_SLICE ||
464 dkpart(dev) != RAW_PART)
474 vio = (struct vn_ioctl *)data;
479 if (vn->sc_flags & VNF_INITED)
482 if (vio->vn_file == NULL)
483 error = vniocattach_swap(vn, vio, dev, flag, td);
485 error = vniocattach_file(vn, vio, dev, flag, td);
489 if ((vn->sc_flags & VNF_INITED) == 0)
492 * XXX handle i/o in progress. Return EBUSY, or wait, or
494 * XXX handle multiple opens of the device. Return EBUSY,
495 * or revoke the fd's.
496 * How are these problems handled for removable and failing
497 * hardware devices? (Hint: They are not)
501 printf("vnioctl: CLRed\n");
515 vn->sc_options |= *f;
520 vn->sc_options &= ~(*f);
534 * Attach a file to a VN partition. Return the size in the vn_size
539 vniocattach_file(struct vn_softc *vn, struct vn_ioctl *vio, dev_t dev,
540 int flag, struct thread *td)
543 struct nlookupdata nd;
546 struct proc *p = td->td_proc;
550 flags = FREAD|FWRITE;
551 error = nlookup_init(&nd, vio->vn_file,
552 UIO_USERSPACE, NLC_FOLLOW|NLC_LOCKVP);
555 if ((error = vn_open(&nd, NULL, flags, 0)) != 0) {
556 if (error != EACCES && error != EPERM && error != EROFS)
560 error = nlookup_init(&nd, vio->vn_file, UIO_USERSPACE, NLC_FOLLOW|NLC_LOCKVP);
563 if ((error = vn_open(&nd, NULL, flags, 0)) != 0)
567 if (vp->v_type != VREG ||
568 (error = VOP_GETATTR(vp, &vattr, td))) {
573 VOP_UNLOCK(vp, 0, td);
574 vn->sc_secsize = DEV_BSIZE;
576 nd.nl_open_vp = NULL;
579 * If the size is specified, override the file attributes. Note that
580 * the vn_size argument is in PAGE_SIZE sized blocks.
583 vn->sc_size = (quad_t)vio->vn_size * PAGE_SIZE / vn->sc_secsize;
585 vn->sc_size = vattr.va_size / vn->sc_secsize;
586 error = vnsetcred(vn, p->p_ucred);
589 vn_close(vp, flags, td);
592 vn->sc_flags |= VNF_INITED;
594 vn->sc_flags |= VNF_READONLY;
595 IFOPT(vn, VN_LABELS) {
597 * Reopen so that `ds' knows which devices are open.
598 * If this is the first VNIOCSET, then we've
599 * guaranteed that the device is the cdev and that
600 * no other slices or labels are open. Otherwise,
601 * we rely on VNIOCCLR not being abused.
603 error = vnopen(dev, flag, S_IFCHR, td);
608 printf("vnioctl: SET vp %p size %x blks\n",
609 vn->sc_vp, vn->sc_size);
618 * Attach swap backing store to a VN partition of the size specified
623 vniocattach_swap(struct vn_softc *vn, struct vn_ioctl *vio, dev_t dev,
624 int flag, struct thread *td)
627 struct proc *p = td->td_proc;
631 * Range check. Disallow negative sizes or any size less then the
632 * size of a page. Then round to a page.
635 if (vio->vn_size <= 0)
639 * Allocate an OBJT_SWAP object.
641 * sc_secsize is PAGE_SIZE'd
643 * vio->vn_size is in PAGE_SIZE'd chunks.
644 * sc_size must be in PAGE_SIZE'd chunks.
645 * Note the truncation.
648 vn->sc_secsize = PAGE_SIZE;
649 vn->sc_size = vio->vn_size;
650 vn->sc_object = vm_pager_allocate(OBJT_SWAP, NULL,
651 vn->sc_secsize * (off_t)vio->vn_size,
653 IFOPT(vn, VN_RESERVE) {
654 if (swap_pager_reserve(vn->sc_object, 0, vn->sc_size) < 0) {
655 vm_pager_deallocate(vn->sc_object);
656 vn->sc_object = NULL;
660 vn->sc_flags |= VNF_INITED;
662 error = vnsetcred(vn, p->p_ucred);
664 IFOPT(vn, VN_LABELS) {
666 * Reopen so that `ds' knows which devices are open.
667 * If this is the first VNIOCSET, then we've
668 * guaranteed that the device is the cdev and that
669 * no other slices or labels are open. Otherwise,
670 * we rely on VNIOCCLR not being abused.
672 error = vnopen(dev, flag, S_IFCHR, td);
676 IFOPT(vn, VN_FOLLOW) {
677 printf("vnioctl: SET vp %p size %x\n",
678 vn->sc_vp, vn->sc_size);
687 * Duplicate the current processes' credentials. Since we are called only
688 * as the result of a SET ioctl and only root can do that, any future access
689 * to this "disk" is essentially as root. Note that credentials may change
690 * if some other uid can write directly to the mapped file (NFS).
693 vnsetcred(struct vn_softc *vn, struct ucred *cred)
699 * Set credits in our softc
704 vn->sc_cred = crdup(cred);
707 * Horrible kludge to establish credentials for NFS XXX.
714 tmpbuf = malloc(vn->sc_secsize, M_TEMP, M_WAITOK);
715 bzero(&auio, sizeof(auio));
717 aiov.iov_base = tmpbuf;
718 aiov.iov_len = vn->sc_secsize;
719 auio.uio_iov = &aiov;
722 auio.uio_rw = UIO_READ;
723 auio.uio_segflg = UIO_SYSSPACE;
724 auio.uio_resid = aiov.iov_len;
725 vn_lock(vn->sc_vp, LK_EXCLUSIVE | LK_RETRY, curthread);
726 error = VOP_READ(vn->sc_vp, &auio, 0, vn->sc_cred);
727 VOP_UNLOCK(vn->sc_vp, 0, curthread);
728 free(tmpbuf, M_TEMP);
734 vnclear(struct vn_softc *vn)
736 struct thread *td = curthread; /* XXX */
739 printf("vnclear(%p): vp=%p\n", vn, vn->sc_vp);
740 if (vn->sc_slices != NULL)
741 dsgone(&vn->sc_slices);
742 vn->sc_flags &= ~VNF_INITED;
743 if (vn->sc_vp != NULL) {
744 vn_close(vn->sc_vp, vn->sc_flags & VNF_READONLY ?
745 FREAD : (FREAD|FWRITE), td);
748 vn->sc_flags &= ~VNF_READONLY;
753 if (vn->sc_object != NULL) {
754 vm_pager_deallocate(vn->sc_object);
755 vn->sc_object = NULL;
768 if ((vn->sc_flags & VNF_INITED) == 0)
775 vn_modevent(module_t mod, int type, void *data)
782 cdevsw_add(&vn_cdevsw, 0, 0);
787 while ((vn = SLIST_FIRST(&vn_list)) != NULL) {
788 SLIST_REMOVE_HEAD(&vn_list, sc_list);
789 if (vn->sc_flags & VNF_INITED)
791 /* Cleanup all dev_t's that refer to this unit */
792 while ((dev = vn->sc_devlist) != NULL) {
793 vn->sc_devlist = dev->si_drv2;
794 dev->si_drv1 = dev->si_drv2 = NULL;
799 cdevsw_remove(&vn_cdevsw, 0, 0);
807 DEV_MODULE(vn, vn_modevent, 0);