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 1.38 2008/07/01 02:02:53 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>
65 #include <sys/nlookup.h>
67 #include <sys/malloc.h>
68 #include <sys/mount.h>
69 #include <sys/vnode.h>
70 #include <sys/fcntl.h>
72 #include <sys/diskslice.h>
75 #include <sys/module.h>
76 #include <sys/vnioctl.h>
79 #include <vm/vm_object.h>
80 #include <vm/vm_page.h>
81 #include <vm/vm_pager.h>
82 #include <vm/vm_pageout.h>
83 #include <vm/swap_pager.h>
84 #include <vm/vm_extern.h>
85 #include <vm/vm_zone.h>
87 static d_ioctl_t vnioctl;
88 static d_open_t vnopen;
89 static d_close_t vnclose;
90 static d_psize_t vnsize;
91 static d_strategy_t vnstrategy;
95 #define VN_BSIZE_BEST 8192
99 * D_DISK we want to look like a disk
100 * D_CANFREE We support BUF_CMD_FREEBLKS
103 static struct dev_ops vn_ops = {
104 { "vn", CDEV_MAJOR, D_DISK | D_CANFREE },
108 .d_write = physwrite,
110 .d_strategy = vnstrategy,
116 int sc_flags; /* flags */
117 u_int64_t sc_size; /* size of vn, sc_secsize scale */
118 int sc_secsize; /* sector size */
119 struct diskslices *sc_slices; /* XXX fields from struct disk */
120 struct disk_info sc_info; /* XXX fields from struct disk */
121 struct vnode *sc_vp; /* vnode if not NULL */
122 vm_object_t sc_object; /* backing object if not NULL */
123 struct ucred *sc_cred; /* credentials */
124 int sc_maxactive; /* max # of active requests */
125 struct buf sc_tab; /* transfer queue */
126 u_long sc_options; /* options */
127 cdev_t sc_devlist; /* devices that refer to this unit */
128 SLIST_ENTRY(vn_softc) sc_list;
131 static SLIST_HEAD(, vn_softc) vn_list;
134 #define VNF_INITED 0x01
135 #define VNF_READONLY 0x02
137 static u_long vn_options;
139 #define IFOPT(vn,opt) if (((vn)->sc_options|vn_options) & (opt))
140 #define TESTOPT(vn,opt) (((vn)->sc_options|vn_options) & (opt))
142 static int vnsetcred (struct vn_softc *vn, struct ucred *cred);
143 static void vnclear (struct vn_softc *vn);
144 static int vnget (cdev_t dev, struct vn_softc *vn , struct vn_user *vnu);
145 static int vn_modevent (module_t, int, void *);
146 static int vniocattach_file (struct vn_softc *, struct vn_ioctl *, cdev_t dev, int flag, struct ucred *cred);
147 static int vniocattach_swap (struct vn_softc *, struct vn_ioctl *, cdev_t dev, int flag, struct ucred *cred);
150 vnclose(struct dev_close_args *ap)
152 cdev_t dev = ap->a_head.a_dev;
153 struct vn_softc *vn = dev->si_drv1;
156 if (vn->sc_slices != NULL)
157 dsclose(dev, ap->a_devtype, vn->sc_slices);
162 * Called only when si_drv1 is NULL. Locate the associated vn node and
163 * attach the device to it.
165 static struct vn_softc *
172 SLIST_FOREACH(vn, &vn_list, sc_list) {
173 if (vn->sc_unit == unit) {
175 dev->si_drv2 = vn->sc_devlist;
176 vn->sc_devlist = dev;
182 vn = kmalloc(sizeof *vn, M_DEVBUF, M_WAITOK | M_ZERO);
185 vn->sc_devlist = make_dev(&vn_ops, 0, UID_ROOT,
186 GID_OPERATOR, 0640, "vn%d", unit);
187 if (vn->sc_devlist->si_drv1 == NULL) {
188 reference_dev(vn->sc_devlist);
189 vn->sc_devlist->si_drv1 = vn;
190 vn->sc_devlist->si_drv2 = NULL;
192 if (vn->sc_devlist != dev) {
194 dev->si_drv2 = vn->sc_devlist;
195 vn->sc_devlist = dev;
198 SLIST_INSERT_HEAD(&vn_list, vn, sc_list);
204 vnopen(struct dev_open_args *ap)
206 cdev_t dev = ap->a_head.a_dev;
208 struct disk_info *info;
211 * Locate preexisting device
214 if ((vn = dev->si_drv1) == NULL)
218 * Update si_bsize fields for device. This data will be overriden by
219 * the slice/parition code for vn accesses through partitions, and
220 * used directly if you open the 'whole disk' device.
222 * si_bsize_best must be reinitialized in case VN has been
223 * reconfigured, plus make it at least VN_BSIZE_BEST for efficiency.
225 dev->si_bsize_phys = vn->sc_secsize;
226 dev->si_bsize_best = vn->sc_secsize;
227 if (dev->si_bsize_best < VN_BSIZE_BEST)
228 dev->si_bsize_best = VN_BSIZE_BEST;
230 if ((ap->a_oflags & FWRITE) && (vn->sc_flags & VNF_READONLY))
234 kprintf("vnopen(%s, 0x%x, 0x%x)\n",
235 devtoname(dev), ap->a_oflags, ap->a_devtype);
241 IFOPT(vn, VN_LABELS) {
242 if (vn->sc_flags & VNF_INITED) {
244 bzero(info, sizeof(*info));
245 info->d_media_blksize = vn->sc_secsize;
246 info->d_media_blocks = vn->sc_size;
248 * reserve mbr sector for backwards compatibility
249 * when no slices exist.
251 info->d_dsflags = DSO_COMPATMBR;
253 info->d_secpertrack = 32;
254 info->d_nheads = 64 / (vn->sc_secsize / DEV_BSIZE);
255 info->d_secpercyl = info->d_secpertrack *
257 info->d_ncylinders = vn->sc_size / info->d_secpercyl;
259 return (dsopen(dev, ap->a_devtype, 0,
260 &vn->sc_slices, info));
262 if (dkslice(dev) != WHOLE_DISK_SLICE ||
263 dkpart(dev) != WHOLE_SLICE_PART ||
264 ap->a_devtype != S_IFCHR) {
274 * Run strategy routine for VN device. We use VOP_READ/VOP_WRITE calls
275 * for vnode-backed vn's, and the new vm_pager_strategy() call for
276 * vm_object-backed vn's.
278 * Currently B_ASYNC is only partially handled - for OBJT_SWAP I/O only.
281 vnstrategy(struct dev_strategy_args *ap)
283 cdev_t dev = ap->a_head.a_dev;
284 struct bio *bio = ap->a_bio;
292 if ((vn = dev->si_drv1) == NULL)
298 kprintf("vnstrategy(%p): unit %d\n", bp, unit);
300 if ((vn->sc_flags & VNF_INITED) == 0) {
302 bp->b_flags |= B_ERROR;
307 bp->b_resid = bp->b_bcount;
309 IFOPT(vn, VN_LABELS) {
311 * The vnode device is using disk/slice label support.
313 * The dscheck() function is called for validating the
314 * slices that exist ON the vnode device itself, and
315 * translate the "slice-relative" block number, again.
316 * dscheck() will call biodone() and return NULL if
317 * we are at EOF or beyond the device size.
319 if (vn->sc_slices == NULL) {
321 } else if ((nbio = dscheck(dev, bio, vn->sc_slices)) == NULL) {
325 int64_t pbn; /* in sc_secsize chunks */
326 long sz; /* in sc_secsize chunks */
329 * Check for required alignment. Transfers must be a valid
330 * multiple of the sector size.
332 if (bp->b_bcount % vn->sc_secsize != 0 ||
333 bio->bio_offset % vn->sc_secsize != 0) {
337 pbn = bio->bio_offset / vn->sc_secsize;
338 sz = howmany(bp->b_bcount, vn->sc_secsize);
341 * Check for an illegal pbn or EOF truncation
345 if (pbn + sz > vn->sc_size) {
346 if (pbn > vn->sc_size || (bp->b_flags & B_BNOCLIP))
348 if (pbn == vn->sc_size) {
349 bp->b_resid = bp->b_bcount;
350 bp->b_flags |= B_INVAL;
353 bp->b_bcount = (vn->sc_size - pbn) * vn->sc_secsize;
355 nbio = push_bio(bio);
356 nbio->bio_offset = pbn * vn->sc_secsize;
360 * Use the translated nbio from this point on
362 if (vn->sc_vp && bp->b_cmd == BUF_CMD_FREEBLKS) {
364 * Freeblks is not handled for vnode-backed elements yet.
367 /* operation complete */
368 } else if (vn->sc_vp) {
372 * If an error occurs, we set B_ERROR but we do not set
373 * B_INVAL because (for a write anyway), the buffer is
379 bzero(&auio, sizeof(auio));
381 aiov.iov_base = bp->b_data;
382 aiov.iov_len = bp->b_bcount;
383 auio.uio_iov = &aiov;
385 auio.uio_offset = nbio->bio_offset;
386 auio.uio_segflg = UIO_SYSSPACE;
387 if (bp->b_cmd == BUF_CMD_READ)
388 auio.uio_rw = UIO_READ;
390 auio.uio_rw = UIO_WRITE;
391 auio.uio_resid = bp->b_bcount;
392 auio.uio_td = curthread;
393 vn_lock(vn->sc_vp, LK_EXCLUSIVE | LK_RETRY);
394 if (bp->b_cmd == BUF_CMD_READ)
395 error = VOP_READ(vn->sc_vp, &auio, IO_DIRECT | IO_RECURSE, vn->sc_cred);
397 error = VOP_WRITE(vn->sc_vp, &auio, IO_DIRECT | IO_RECURSE, vn->sc_cred);
398 vn_unlock(vn->sc_vp);
399 bp->b_resid = auio.uio_resid;
402 bp->b_flags |= B_ERROR;
404 /* operation complete */
405 } else if (vn->sc_object) {
407 * OBJT_SWAP I/O (handles read, write, freebuf)
409 * We have nothing to do if freeing blocks on a reserved
410 * swap area, othrewise execute the op.
412 if (bp->b_cmd == BUF_CMD_FREEBLKS && TESTOPT(vn, VN_RESERVE)) {
414 /* operation complete */
416 vm_pager_strategy(vn->sc_object, nbio);
421 bp->b_resid = bp->b_bcount;
422 bp->b_flags |= B_ERROR | B_INVAL;
423 bp->b_error = EINVAL;
424 /* operation complete */
430 * Shortcuts / check failures on the original bio (not nbio).
433 bp->b_error = EINVAL;
434 bp->b_flags |= B_ERROR | B_INVAL;
442 vnioctl(struct dev_ioctl_args *ap)
444 cdev_t dev = ap->a_head.a_dev;
446 struct vn_ioctl *vio;
451 IFOPT(vn,VN_FOLLOW) {
452 kprintf("vnioctl(%s, 0x%lx, %p, 0x%x): unit %d\n",
453 devtoname(dev), ap->a_cmd, ap->a_data, ap->a_fflag,
468 IFOPT(vn,VN_LABELS) {
469 if (vn->sc_slices != NULL) {
470 error = dsioctl(dev, ap->a_cmd, ap->a_data,
472 &vn->sc_slices, &vn->sc_info);
473 if (error != ENOIOCTL)
476 if (dkslice(dev) != WHOLE_DISK_SLICE ||
477 dkpart(dev) != WHOLE_SLICE_PART)
483 error = priv_check_cred(ap->a_cred, PRIV_ROOT, 0);
487 vio = (struct vn_ioctl *)ap->a_data;
488 f = (u_long*)ap->a_data;
492 if (vn->sc_flags & VNF_INITED)
495 if (vio->vn_file == NULL)
496 error = vniocattach_swap(vn, vio, dev, ap->a_fflag, ap->a_cred);
498 error = vniocattach_file(vn, vio, dev, ap->a_fflag, ap->a_cred);
502 if ((vn->sc_flags & VNF_INITED) == 0)
505 * XXX handle i/o in progress. Return EBUSY, or wait, or
507 * XXX handle multiple opens of the device. Return EBUSY,
508 * or revoke the fd's.
509 * How are these problems handled for removable and failing
510 * hardware devices? (Hint: They are not)
512 if (count_dev(vn->sc_devlist) > 1)
517 kprintf("vnioctl: CLRed\n");
521 error = vnget(dev, vn, (struct vn_user *) ap->a_data);
535 vn->sc_options |= *f;
540 vn->sc_options &= ~(*f);
554 * Attach a file to a VN partition. Return the size in the vn_size
559 vniocattach_file(struct vn_softc *vn, struct vn_ioctl *vio, cdev_t dev,
560 int flag, struct ucred *cred)
563 struct nlookupdata nd;
567 flags = FREAD|FWRITE;
568 error = nlookup_init(&nd, vio->vn_file,
569 UIO_USERSPACE, NLC_FOLLOW|NLC_LOCKVP);
572 if ((error = vn_open(&nd, NULL, flags, 0)) != 0) {
573 if (error != EACCES && error != EPERM && error != EROFS)
577 error = nlookup_init(&nd, vio->vn_file, UIO_USERSPACE, NLC_FOLLOW|NLC_LOCKVP);
580 if ((error = vn_open(&nd, NULL, flags, 0)) != 0)
584 if (vp->v_type != VREG ||
585 (error = VOP_GETATTR(vp, &vattr))) {
591 vn->sc_secsize = DEV_BSIZE;
593 nd.nl_open_vp = NULL;
596 * If the size is specified, override the file attributes. Note that
597 * the vn_size argument is in PAGE_SIZE sized blocks.
600 vn->sc_size = vio->vn_size * PAGE_SIZE / vn->sc_secsize;
602 vn->sc_size = vattr.va_size / vn->sc_secsize;
603 error = vnsetcred(vn, cred);
609 vn->sc_flags |= VNF_INITED;
611 vn->sc_flags |= VNF_READONLY;
612 IFOPT(vn, VN_LABELS) {
614 * Reopen so that `ds' knows which devices are open.
615 * If this is the first VNIOCSET, then we've
616 * guaranteed that the device is the cdev and that
617 * no other slices or labels are open. Otherwise,
618 * we rely on VNIOCCLR not being abused.
620 error = dev_dopen(dev, flag, S_IFCHR, cred);
625 kprintf("vnioctl: SET vp %p size %llx blks\n",
626 vn->sc_vp, vn->sc_size);
635 * Attach swap backing store to a VN partition of the size specified
640 vniocattach_swap(struct vn_softc *vn, struct vn_ioctl *vio, cdev_t dev,
641 int flag, struct ucred *cred)
646 * Range check. Disallow negative sizes or any size less then the
647 * size of a page. Then round to a page.
650 if (vio->vn_size <= 0)
654 * Allocate an OBJT_SWAP object.
656 * sc_secsize is PAGE_SIZE'd
658 * vio->vn_size is in PAGE_SIZE'd chunks.
659 * sc_size must be in PAGE_SIZE'd chunks.
660 * Note the truncation.
663 vn->sc_secsize = PAGE_SIZE;
664 vn->sc_size = vio->vn_size;
665 vn->sc_object = vm_pager_allocate(OBJT_SWAP, NULL,
666 vn->sc_secsize * (off_t)vio->vn_size,
668 IFOPT(vn, VN_RESERVE) {
669 if (swap_pager_reserve(vn->sc_object, 0, vn->sc_size) < 0) {
670 vm_pager_deallocate(vn->sc_object);
671 vn->sc_object = NULL;
675 vn->sc_flags |= VNF_INITED;
677 error = vnsetcred(vn, cred);
679 IFOPT(vn, VN_LABELS) {
681 * Reopen so that `ds' knows which devices are open.
682 * If this is the first VNIOCSET, then we've
683 * guaranteed that the device is the cdev and that
684 * no other slices or labels are open. Otherwise,
685 * we rely on VNIOCCLR not being abused.
687 error = dev_dopen(dev, flag, S_IFCHR, cred);
691 IFOPT(vn, VN_FOLLOW) {
692 kprintf("vnioctl: SET vp %p size %llx\n",
693 vn->sc_vp, vn->sc_size);
702 * Duplicate the current processes' credentials. Since we are called only
703 * as the result of a SET ioctl and only root can do that, any future access
704 * to this "disk" is essentially as root. Note that credentials may change
705 * if some other uid can write directly to the mapped file (NFS).
708 vnsetcred(struct vn_softc *vn, struct ucred *cred)
714 * Set credits in our softc
719 vn->sc_cred = crdup(cred);
722 * Horrible kludge to establish credentials for NFS XXX.
729 tmpbuf = kmalloc(vn->sc_secsize, M_TEMP, M_WAITOK);
730 bzero(&auio, sizeof(auio));
732 aiov.iov_base = tmpbuf;
733 aiov.iov_len = vn->sc_secsize;
734 auio.uio_iov = &aiov;
737 auio.uio_rw = UIO_READ;
738 auio.uio_segflg = UIO_SYSSPACE;
739 auio.uio_resid = aiov.iov_len;
740 vn_lock(vn->sc_vp, LK_EXCLUSIVE | LK_RETRY);
741 error = VOP_READ(vn->sc_vp, &auio, 0, vn->sc_cred);
742 vn_unlock(vn->sc_vp);
743 kfree(tmpbuf, M_TEMP);
749 vnclear(struct vn_softc *vn)
752 kprintf("vnclear(%p): vp=%p\n", vn, vn->sc_vp);
753 if (vn->sc_slices != NULL)
754 dsgone(&vn->sc_slices);
755 vn->sc_flags &= ~VNF_INITED;
756 if (vn->sc_vp != NULL) {
758 (vn->sc_flags & VNF_READONLY) ? FREAD : (FREAD|FWRITE));
761 vn->sc_flags &= ~VNF_READONLY;
766 if (vn->sc_object != NULL) {
767 vm_pager_deallocate(vn->sc_object);
768 vn->sc_object = NULL;
776 * populate a struct vn_user for the VNIOCGET ioctl.
777 * interface conventions defined in sys/sys/vnioctl.h.
781 vnget(cdev_t dev, struct vn_softc *vn, struct vn_user *vnu)
783 int error, found = 0;
784 char *freepath, *fullpath;
787 if (vnu->vnu_unit == -1) {
788 vnu->vnu_unit = dkunit(dev);
790 else if (vnu->vnu_unit < 0)
793 SLIST_FOREACH(vn, &vn_list, sc_list) {
795 if(vn->sc_unit != vnu->vnu_unit)
800 if (vn->sc_flags & VNF_INITED && vn->sc_vp != NULL) {
802 /* note: u_cred checked in vnioctl above */
803 error = VOP_GETATTR(vn->sc_vp, &vattr);
805 kprintf("vnget: VOP_GETATTR for %p failed\n",
810 error = vn_fullpath(curproc, vn->sc_vp,
811 &fullpath, &freepath);
814 kprintf("vnget: unable to resolve vp %p\n",
819 strlcpy(vnu->vnu_file, fullpath,
820 sizeof(vnu->vnu_file));
821 kfree(freepath, M_TEMP);
822 vnu->vnu_dev = vattr.va_fsid;
823 vnu->vnu_ino = vattr.va_fileid;
826 else if (vn->sc_flags & VNF_INITED && vn->sc_object != NULL){
828 strlcpy(vnu->vnu_file, _VN_USER_SWAP,
829 sizeof(vnu->vnu_file));
830 vnu->vnu_size = vn->sc_size;
831 vnu->vnu_secsize = vn->sc_secsize;
835 bzero(vnu->vnu_file, sizeof(vnu->vnu_file));
850 vnsize(struct dev_psize_args *ap)
852 cdev_t dev = ap->a_head.a_dev;
858 if ((vn->sc_flags & VNF_INITED) == 0)
860 ap->a_result = (int64_t)vn->sc_size;
865 vn_modevent(module_t mod, int type, void *data)
872 dev_ops_add(&vn_ops, 0, 0);
877 while ((vn = SLIST_FIRST(&vn_list)) != NULL) {
878 SLIST_REMOVE_HEAD(&vn_list, sc_list);
879 if (vn->sc_flags & VNF_INITED)
881 /* Cleanup all cdev_t's that refer to this unit */
882 while ((dev = vn->sc_devlist) != NULL) {
883 vn->sc_devlist = dev->si_drv2;
884 dev->si_drv1 = dev->si_drv2 = NULL;
889 dev_ops_remove(&vn_ops, 0, 0);
897 DEV_MODULE(vn, vn_modevent, 0);