/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)spec_vnops.c 8.15 (Berkeley) 7/14/95
*/
static vnode_t *specfs_hash[SPECHSZ];
extern struct mount *dead_rootmount;
/*
* This vnode operations vector is used for special device nodes
* created from whole cloth by the kernel. For the ops vector for
* vnodes built from special devices found in a filesystem, see (e.g)
* ffs_specop_entries[] in ffs_vnops.c or the equivalent for other
* filesystems.
*/
/*
* Returns true if vnode is /dev/mem or /dev/kmem.
*/
bool
iskmemvp(struct vnode *vp)
{
return ((vp->v_type == VCHR) && iskmemdev(vp->v_rdev));
}
/*
* Returns true if dev is /dev/mem or /dev/kmem.
*/
int
iskmemdev(dev_t dev)
{
/* mem_no is emitted by config(8) to generated devsw.c */
extern const int mem_no;
/* minor 14 is /dev/io on i386 with COMPAT_10 */
return (major(dev) == mem_no && (minor(dev) < 2 || minor(dev) == 14));
}
static int
rawio_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
void *arg0, void *arg1, void *arg2, void *arg3)
{
int result;
result = KAUTH_RESULT_DEFER;
if ((action != KAUTH_DEVICE_RAWIO_SPEC) &&
(action != KAUTH_DEVICE_RAWIO_PASSTHRU))
return result;
/* Access is mandated by permissions. */
result = KAUTH_RESULT_ALLOW;
/*
* spec_io_enter(vp, &sn, &dev)
*
* Enter an operation that may not hold vp's vnode lock or an
* fstrans on vp's mount. Until spec_io_exit, the vnode will not
* be revoked.
*
* On success, set sn to the specnode pointer and dev to the dev_t
* number and return zero. Caller must later call spec_io_exit
* when done.
*
* On failure, return ENXIO -- the device has been revoked and no
* longer exists.
*/
static int
spec_io_enter(struct vnode *vp, struct specnode **snp, dev_t *devp)
{
dev_t dev;
struct specnode *sn;
unsigned iocnt;
int error = 0;
mutex_enter(vp->v_interlock);
/*
* Extract all the info we need from the vnode, unless the
* vnode has already been reclaimed. This can happen if the
* underlying device has been removed and all the device nodes
* for it have been revoked. The caller may not hold a vnode
* lock or fstrans to prevent this from happening before it has
* had an opportunity to notice the vnode is dead.
*/
if (vdead_check(vp, VDEAD_NOWAIT) != 0 ||
(sn = vp->v_specnode) == NULL ||
(dev = vp->v_rdev) == NODEV) {
error = ENXIO;
goto out;
}
/*
* Notify spec_close that we are doing an I/O operation which
* may not be not bracketed by fstrans(9) and thus is not
* blocked by vfs suspension.
*
* We could hold this reference with psref(9) instead, but we
* already have to take the interlock for vdead_check, so
* there's not much more cost here to another atomic operation.
*/
do {
iocnt = atomic_load_relaxed(&sn->sn_dev->sd_iocnt);
if (__predict_false(iocnt == UINT_MAX)) {
/*
* The I/O count is limited by the number of
* LWPs (which will never overflow this) --
* unless one driver uses another driver via
* specfs, which is rather unusual, but which
* could happen via pud(4) userspace drivers.
* We could use a 64-bit count, but can't use
* atomics for that on all platforms.
* (Probably better to switch to psref or
* localcount instead.)
*/
error = EBUSY;
goto out;
}
} while (atomic_cas_uint(&sn->sn_dev->sd_iocnt, iocnt, iocnt + 1)
!= iocnt);
/* Success! */
*snp = sn;
*devp = dev;
error = 0;
out: mutex_exit(vp->v_interlock);
return error;
}
/*
* spec_io_exit(vp, sn)
*
* Exit an operation entered with a successful spec_io_enter --
* allow concurrent spec_node_revoke to proceed. The argument sn
* must match the struct specnode pointer returned by spec_io_exit
* for vp.
*/
static void
spec_io_exit(struct vnode *vp, struct specnode *sn)
{
struct specdev *sd = sn->sn_dev;
unsigned iocnt;
KASSERT(vp->v_specnode == sn);
/*
* We are done. Notify spec_close if appropriate. The
* transition of 1 -> 0 must happen under device_lock so
* spec_close doesn't miss a wakeup.
*/
do {
iocnt = atomic_load_relaxed(&sd->sd_iocnt);
KASSERT(iocnt > 0);
if (iocnt == 1) {
mutex_enter(&device_lock);
if (atomic_dec_uint_nv(&sd->sd_iocnt) == 0)
cv_broadcast(&specfs_iocv);
mutex_exit(&device_lock);
break;
}
} while (atomic_cas_uint(&sd->sd_iocnt, iocnt, iocnt - 1) != iocnt);
}
/*
* spec_io_drain(sd)
*
* Wait for all existing spec_io_enter/exit sections to complete.
* Caller must ensure spec_io_enter will fail at this point.
*/
static void
spec_io_drain(struct specdev *sd)
{
/*
* I/O at the same time as closing is unlikely -- it often
* indicates an application bug.
*/
if (__predict_true(atomic_load_relaxed(&sd->sd_iocnt) == 0))
return;
mutex_enter(&device_lock);
while (atomic_load_relaxed(&sd->sd_iocnt) > 0)
cv_wait(&specfs_iocv, &device_lock);
mutex_exit(&device_lock);
}
/*
* Initialize a vnode that represents a device.
*/
void
spec_node_init(vnode_t *vp, dev_t rdev)
{
specnode_t *sn;
specdev_t *sd;
vnode_t *vp2;
vnode_t **vpp;
/*
* Search the hash table for this device. If known, add a
* reference to the device structure. If not known, create
* a new entry to represent the device. In all cases add
* the vnode to the hash table.
*/
sn = kmem_alloc(sizeof(*sn), KM_SLEEP);
sd = kmem_alloc(sizeof(*sd), KM_SLEEP);
mutex_enter(&device_lock);
vpp = &specfs_hash[SPECHASH(rdev)];
for (vp2 = *vpp; vp2 != NULL; vp2 = vp2->v_specnext) {
KASSERT(vp2->v_specnode != NULL);
if (rdev == vp2->v_rdev && vp->v_type == vp2->v_type) {
break;
}
}
if (vp2 == NULL) {
/* No existing record, create a new one. */
sd->sd_mountpoint = NULL;
sd->sd_lockf = NULL;
sd->sd_refcnt = 1;
sd->sd_opencnt = 0;
sd->sd_bdevvp = NULL;
sd->sd_iocnt = 0;
sd->sd_opened = false;
sd->sd_closing = false;
sn->sn_dev = sd;
sd = NULL;
} else {
/* Use the existing record. */
sn->sn_dev = vp2->v_specnode->sn_dev;
sn->sn_dev->sd_refcnt++;
}
/* Insert vnode into the hash chain. */
sn->sn_opencnt = 0;
sn->sn_rdev = rdev;
sn->sn_gone = false;
vp->v_specnode = sn;
vp->v_specnext = *vpp;
*vpp = vp;
mutex_exit(&device_lock);
/* Free the record we allocated if unused. */
if (sd != NULL) {
kmem_free(sd, sizeof(*sd));
}
}
/*
* Lookup a vnode by device number and return it referenced.
*/
int
spec_node_lookup_by_dev(enum vtype type, dev_t dev, int flags, vnode_t **vpp)
{
int error;
vnode_t *vp;
top: mutex_enter(&device_lock);
for (vp = specfs_hash[SPECHASH(dev)]; vp; vp = vp->v_specnext) {
if (type == vp->v_type && dev == vp->v_rdev) {
mutex_enter(vp->v_interlock);
/* If clean or being cleaned, then ignore it. */
if (vdead_check(vp, VDEAD_NOWAIT) == 0)
break;
if ((flags & VDEAD_NOWAIT) == 0) {
mutex_exit(&device_lock);
/*
* It may be being revoked as we speak,
* and the caller wants to wait until
* all revocation has completed. Let
* vcache_vget wait for it to finish
* dying; as a side effect, vcache_vget
* releases vp->v_interlock. Note that
* vcache_vget cannot succeed at this
* point because vdead_check already
* failed.
*/
error = vcache_vget(vp);
KASSERT(error);
goto top;
}
mutex_exit(vp->v_interlock);
}
}
KASSERT(vp == NULL || mutex_owned(vp->v_interlock));
if (vp == NULL) {
mutex_exit(&device_lock);
return ENOENT;
}
/*
* If it is an opened block device return the opened vnode.
*/
if (type == VBLK && vp->v_specnode->sn_dev->sd_bdevvp != NULL) {
mutex_exit(vp->v_interlock);
vp = vp->v_specnode->sn_dev->sd_bdevvp;
mutex_enter(vp->v_interlock);
}
mutex_exit(&device_lock);
error = vcache_vget(vp);
if (error)
return error;
*vpp = vp;
return 0;
}
/*
* Lookup a vnode by file system mounted on and return it referenced.
*/
int
spec_node_lookup_by_mount(struct mount *mp, vnode_t **vpp)
{
int i, error;
vnode_t *vp, *vq;
mutex_enter(&device_lock);
for (i = 0, vq = NULL; i < SPECHSZ && vq == NULL; i++) {
for (vp = specfs_hash[i]; vp; vp = vp->v_specnext) {
if (vp->v_type != VBLK)
continue;
vq = vp->v_specnode->sn_dev->sd_bdevvp;
if (vq != NULL &&
vq->v_specnode->sn_dev->sd_mountpoint == mp)
break;
vq = NULL;
}
}
if (vq == NULL) {
mutex_exit(&device_lock);
return ENOENT;
}
mutex_enter(vq->v_interlock);
mutex_exit(&device_lock);
error = vcache_vget(vq);
if (error)
return error;
*vpp = vq;
return 0;
}
/*
* Get the file system mounted on this block device.
*
* XXX Caller should hold the vnode lock -- shared or exclusive -- so
* that this can't changed, and the vnode can't be revoked while we
* examine it. But not all callers do, and they're scattered through a
* lot of file systems, so we can't assert this yet.
*/
struct mount *
spec_node_getmountedfs(vnode_t *devvp)
{
struct mount *mp;
/*
* Set the file system mounted on this block device.
*
* XXX Caller should hold the vnode lock exclusively so this can't be
* changed or assumed by spec_node_getmountedfs while we change it, and
* the vnode can't be revoked while we handle it. But not all callers
* do, and they're scattered through a lot of file systems, so we can't
* assert this yet. Instead, for now, we'll take an I/O reference so
* at least the ioctl doesn't race with revoke/detach.
*
* If you do change this to assert an exclusive vnode lock, you must
* also do vdead_check before trying bdev_ioctl, because the vnode may
* have been revoked by the time the caller locked it, and this is
* _not_ a vop -- calls to spec_node_setmountedfs don't go through
* v_op, so revoking the vnode doesn't prevent further calls.
*
* XXX Caller should additionally have the vnode open, at least if mp
* is nonnull, but I'm not sure all callers do that -- need to audit.
* Currently udf closes the vnode before clearing the mount.
*/
void
spec_node_setmountedfs(vnode_t *devvp, struct mount *mp)
{
struct dkwedge_info dkw;
struct specnode *sn;
dev_t dev;
int error;
KASSERT(devvp->v_type == VBLK);
error = spec_io_enter(devvp, &sn, &dev);
if (error)
return;
/*
* A vnode representing a special device is going away. Close
* the device if the vnode holds it open.
*/
void
spec_node_revoke(vnode_t *vp)
{
specnode_t *sn;
specdev_t *sd;
struct vnode **vpp;
/*
* We may have revoked the vnode in this thread while another
* thread was in the middle of spec_close, in the window when
* spec_close releases the vnode lock to call .d_close for the
* last close. In that case, wait for the concurrent
* spec_close to complete.
*/
while (sd->sd_closing)
cv_wait(&specfs_iocv, &device_lock);
/*
* Remove from the hash so lookups stop returning this
* specnode. We will dissociate it from the specdev -- and
* possibly free the specdev -- in spec_node_destroy.
*/
KASSERT(sn->sn_gone);
KASSERT(sn->sn_opencnt == 0);
for (vpp = &specfs_hash[SPECHASH(vp->v_rdev)];;
vpp = &(*vpp)->v_specnext) {
if (*vpp == vp) {
*vpp = vp->v_specnext;
vp->v_specnext = NULL;
break;
}
}
mutex_exit(&device_lock);
}
/*
* A vnode representing a special device is being recycled.
* Destroy the specfs component.
*/
void
spec_node_destroy(vnode_t *vp)
{
specnode_t *sn;
specdev_t *sd;
int refcnt;
/*
* Acquire an open reference -- as long as we hold onto it, and
* the vnode isn't revoked, it can't be closed, and the vnode
* can't be revoked until we release the vnode lock.
*/
mutex_enter(&device_lock);
KASSERT(!sn->sn_gone);
switch (vp->v_type) {
case VCHR:
/*
* Character devices can accept opens from multiple
* vnodes. But first, wait for any close to finish.
* Wait under the vnode lock so we don't have to worry
* about the vnode being revoked while we wait.
*/
while (sd->sd_closing) {
error = cv_wait_sig(&specfs_iocv, &device_lock);
if (error)
break;
}
if (error)
break;
sd->sd_opencnt++;
sn->sn_opencnt++;
KASSERTMSG(sn->sn_opencnt <= sd->sd_opencnt,
"sn_opencnt=%u > sd_opencnt=%u",
sn->sn_opencnt, sd->sd_opencnt);
break;
case VBLK:
/*
* For block devices, permit only one open. The buffer
* cache cannot remain self-consistent with multiple
* vnodes holding a block device open.
*
* Treat zero opencnt with non-NULL mountpoint as open.
* This may happen after forced detach of a mounted device.
*
* Also treat sd_closing, meaning there is a concurrent
* close in progress, as still open.
*/
if (sd->sd_opencnt != 0 ||
sd->sd_mountpoint != NULL ||
sd->sd_closing) {
error = EBUSY;
break;
}
KASSERTMSG(sn->sn_opencnt == 0, "sn_opencnt=%u",
sn->sn_opencnt);
sn->sn_opencnt = 1;
sd->sd_opencnt = 1;
sd->sd_bdevvp = vp;
break;
default:
panic("invalid specfs vnode type: %d", vp->v_type);
}
mutex_exit(&device_lock);
if (error)
return error;
/*
* Set VV_ISTTY if this is a tty cdev.
*
* XXX This does the wrong thing if the module has to be
* autoloaded. We should maybe set this after autoloading
* modules and calling .d_open successfully, except (a) we need
* the vnode lock to touch it, and (b) once we acquire the
* vnode lock again, the vnode may have been revoked, and
* deadfs's dead_read needs VV_ISTTY to be already set in order
* to return the right answer. So this needs some additional
* synchronization to be made to work correctly with tty driver
* module autoload. For now, let's just hope it doesn't cause
* too much trouble for a tty from an autoloaded driver module
* to fail with EIO instead of returning EOF.
*/
if (vp->v_type == VCHR) {
if (cdev_type(dev) == D_TTY)
vp->v_vflag |= VV_ISTTY;
}
/*
* Because opening the device may block indefinitely, e.g. when
* opening a tty, and loading a module may cross into many
* other subsystems, we must not hold the vnode lock while
* calling .d_open, so release it now and reacquire it when
* done.
*
* Take an I/O reference so that any concurrent spec_close via
* spec_node_revoke will wait for us to finish calling .d_open.
* The vnode can't be dead at this point because we have it
* locked. Note that if revoked, the driver must interrupt
* .d_open before spec_close starts waiting for I/O to drain so
* this doesn't deadlock.
*/
VOP_UNLOCK(vp);
error = spec_io_enter(vp, &sn1, &dev1);
if (error) {
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
return error;
}
KASSERT(sn1 == sn);
KASSERT(dev1 == dev);
/*
* Open the device. If .d_open returns ENXIO (device not
* configured), the driver may not be loaded, so try
* autoloading a module and then try .d_open again if anything
* got loaded.
*/
switch (vp->v_type) {
case VCHR:
do {
const struct cdevsw *cdev;
gen = module_gen;
error = cdev_open(dev, ap->a_mode, S_IFCHR, l);
if (error != ENXIO)
break;
/* Check if we already have a valid driver */
mutex_enter(&device_lock);
cdev = cdevsw_lookup(dev);
mutex_exit(&device_lock);
if (cdev != NULL)
break;
/* Get device name from devsw_conv array */
if ((name = cdevsw_getname(major(dev))) == NULL)
break;
/* Try to autoload device module */
(void)module_autoload(name, MODULE_CLASS_DRIVER);
} while (gen != module_gen);
break;
case VBLK:
do {
const struct bdevsw *bdev;
gen = module_gen;
error = bdev_open(dev, ap->a_mode, S_IFBLK, l);
if (error != ENXIO)
break;
/* Check if we already have a valid driver */
mutex_enter(&device_lock);
bdev = bdevsw_lookup(dev);
mutex_exit(&device_lock);
if (bdev != NULL)
break;
/* Get device name from devsw_conv array */
if ((name = bdevsw_getname(major(dev))) == NULL)
break;
/* Try to autoload device module */
(void)module_autoload(name, MODULE_CLASS_DRIVER);
} while (gen != module_gen);
break;
default:
__unreachable();
}
/*
* Release the I/O reference now that we have called .d_open,
* and reacquire the vnode lock. At this point, the device may
* have been revoked, so we must tread carefully. However, sn
* and sd remain valid pointers until we drop our reference.
*/
spec_io_exit(vp, sn);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
KASSERT(vp->v_specnode == sn);
/*
* If it has been revoked since we released the vnode lock and
* reacquired it, then spec_node_revoke has closed it, and we
* must fail with EBADF.
*
* Otherwise, if opening it failed, back out and release the
* open reference. If it was ever successfully opened and we
* got the last reference this way, it's now our job to close
* it. This might happen in the following scenario:
*
* Thread 1 Thread 2
* VOP_OPEN
* ...
* .d_open -> 0 (success)
* acquire vnode lock
* do stuff VOP_OPEN
* release vnode lock ...
* .d_open -> EBUSY
* VOP_CLOSE
* acquire vnode lock
* --sd_opencnt != 0
* => no .d_close
* release vnode lock
* acquire vnode lock
* --sd_opencnt == 0
*
* We can't resolve this by making spec_close wait for .d_open
* to complete before examining sd_opencnt, because .d_open can
* hang indefinitely, e.g. for a tty.
*/
mutex_enter(&device_lock);
if (sn->sn_gone) {
if (error == 0)
error = EBADF;
} else if (error == 0) {
/*
* Device has not been revoked, so our opencnt can't
* have gone away at this point -- transition to
* sn_gone=true happens before transition to
* sn_opencnt=0 in spec_node_revoke.
*/
KASSERT(sd->sd_opencnt);
KASSERT(sn->sn_opencnt);
KASSERTMSG(sn->sn_opencnt <= sd->sd_opencnt,
"sn_opencnt=%u > sd_opencnt=%u",
sn->sn_opencnt, sd->sd_opencnt);
KASSERT(!sd->sd_closing);
sd->sd_opened = true;
} else if (sd->sd_opencnt == 1 && sd->sd_opened) {
/*
* We're the last reference to a _previous_ open even
* though this one failed, so we have to close it.
* Don't decrement the reference count here --
* spec_close will do that.
*/
KASSERT(sn->sn_opencnt == 1);
needclose = true;
} else {
KASSERT(sd->sd_opencnt);
KASSERT(sn->sn_opencnt);
KASSERTMSG(sn->sn_opencnt <= sd->sd_opencnt,
"sn_opencnt=%u > sd_opencnt=%u",
sn->sn_opencnt, sd->sd_opencnt);
sd->sd_opencnt--;
sn->sn_opencnt--;
if (vp->v_type == VBLK)
sd->sd_bdevvp = NULL;
}
mutex_exit(&device_lock);
/*
* If this open failed, but the device was previously opened,
* and another thread concurrently closed the vnode while we
* were in the middle of reopening it, the other thread will
* see sd_opencnt > 0 and thus decide not to call .d_close --
* it is now our responsibility to do so.
*
* XXX The flags passed to VOP_CLOSE here are wrong, but
* drivers can't rely on FREAD|FWRITE anyway -- e.g., consider
* a device opened by thread 0 with O_READ, then opened by
* thread 1 with O_WRITE, then closed by thread 0, and finally
* closed by thread 1; the last .d_close call will have FWRITE
* but not FREAD. We should just eliminate the FREAD/FWRITE
* parameter to .d_close altogether.
*/
if (needclose) {
KASSERT(error);
VOP_CLOSE(vp, FNONBLOCK, NOCRED);
}
/* If anything went wrong, we're done. */
if (error)
return error;
/*
* For disk devices, automagically set the vnode size to the
* partition size, if we can. This applies to block devices
* and character devices alike -- every block device must have
* a corresponding character device. And if the module is
* loaded it will remain loaded until we're done here (it is
* forbidden to devsw_detach until closed). So it is safe to
* query cdev_type unconditionally here.
*/
switch (vp->v_type) {
case VCHR:
ioctl = cdev_ioctl;
dtype = cdev_type(dev);
break;
default:
ioctl = bdev_ioctl;
dtype = bdev_type(dev);
break;
}
if (dtype == D_DISK) {
struct partinfo pi;
off_t sz;
if (error == 0)
uvm_vnp_setsize(vp, (voff_t)sz);
}
/* Success! */
return 0;
}
/*
* Vnode op for read
*/
/* ARGSUSED */
int
spec_read(void *v)
{
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
kauth_cred_t a_cred;
} */ *ap = v;
struct vnode *vp = ap->a_vp;
struct uio *uio = ap->a_uio;
struct lwp *l = curlwp;
struct specnode *sn;
dev_t dev;
struct buf *bp;
daddr_t bn;
int bsize, bscale;
struct partinfo pi;
int n, on;
int error = 0;
int i, nra;
daddr_t lastbn, *rablks;
int *rasizes;
int nrablks, ratogo;
KASSERT(uio->uio_rw == UIO_READ);
KASSERTMSG((VMSPACE_IS_KERNEL_P(uio->uio_vmspace) ||
uio->uio_vmspace == curproc->p_vmspace),
"vmspace belongs to neither kernel nor curproc");
if (uio->uio_resid == 0)
return 0;
switch (vp->v_type) {
case VCHR:
/*
* Release the lock while we sleep -- possibly
* indefinitely, if this is, e.g., a tty -- in
* cdev_read, so we don't hold up everything else that
* might want access to the vnode.
*
* But before we issue the read, take an I/O reference
* to the specnode so close will know when we're done
* reading. Note that the moment we release the lock,
* the vnode's identity may change; hence spec_io_enter
* may fail, and the caller may have a dead vnode on
* their hands, if the file system on which vp lived
* has been unmounted.
*/
VOP_UNLOCK(vp);
error = spec_io_enter(vp, &sn, &dev);
if (error)
goto out;
error = cdev_read(dev, uio, ap->a_ioflag);
spec_io_exit(vp, sn);
out: /* XXX What if the caller held an exclusive lock? */
vn_lock(vp, LK_SHARED | LK_RETRY);
return error;
case VBLK:
KASSERT(vp == vp->v_specnode->sn_dev->sd_bdevvp);
if (uio->uio_offset < 0)
return EINVAL;
/*
* Vnode op for write
*/
/* ARGSUSED */
int
spec_write(void *v)
{
struct vop_write_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
kauth_cred_t a_cred;
} */ *ap = v;
struct vnode *vp = ap->a_vp;
struct uio *uio = ap->a_uio;
struct lwp *l = curlwp;
struct specnode *sn;
dev_t dev;
struct buf *bp;
daddr_t bn;
int bsize, bscale;
struct partinfo pi;
int n, on;
int error = 0;
KASSERT(uio->uio_rw == UIO_WRITE);
KASSERTMSG((VMSPACE_IS_KERNEL_P(uio->uio_vmspace) ||
uio->uio_vmspace == curproc->p_vmspace),
"vmspace belongs to neither kernel nor curproc");
switch (vp->v_type) {
case VCHR:
/*
* Release the lock while we sleep -- possibly
* indefinitely, if this is, e.g., a tty -- in
* cdev_write, so we don't hold up everything else that
* might want access to the vnode.
*
* But before we issue the write, take an I/O reference
* to the specnode so close will know when we're done
* writing. Note that the moment we release the lock,
* the vnode's identity may change; hence spec_io_enter
* may fail, and the caller may have a dead vnode on
* their hands, if the file system on which vp lived
* has been unmounted.
*/
VOP_UNLOCK(vp);
error = spec_io_enter(vp, &sn, &dev);
if (error)
goto out;
error = cdev_write(dev, uio, ap->a_ioflag);
spec_io_exit(vp, sn);
out: vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
return error;
case VBLK:
KASSERT(vp == vp->v_specnode->sn_dev->sd_bdevvp);
if (uio->uio_resid == 0)
return 0;
if (uio->uio_offset < 0)
return EINVAL;
/*
* fdiscard, which on disk devices becomes TRIM.
*/
int
spec_fdiscard(void *v)
{
struct vop_fdiscard_args /* {
struct vnode *a_vp;
off_t a_pos;
off_t a_len;
} */ *ap = v;
struct vnode *vp = ap->a_vp;
dev_t dev;
KASSERT(VOP_ISLOCKED(vp) == LK_EXCLUSIVE);
dev = vp->v_rdev;
switch (vp->v_type) {
case VCHR:
#if 0 /* This is not stored for character devices. */
KASSERT(vp == vp->v_specnode->sn_dev->sd_cdevvp);
#endif
return cdev_discard(dev, ap->a_pos, ap->a_len);
case VBLK:
KASSERT(vp == vp->v_specnode->sn_dev->sd_bdevvp);
return bdev_discard(dev, ap->a_pos, ap->a_len);
default:
panic("spec_fdiscard: not a device\n");
}
}
error = spec_io_enter(vp, &sn, &dev);
if (error)
return error;
switch (vp->v_type) {
case VCHR:
error = cdev_kqfilter(dev, ap->a_kn);
break;
default:
/*
* Block devices don't support kqfilter, and refuse it
* for any other files (like those vflush()ed) too.
*/
error = EOPNOTSUPP;
break;
}
spec_io_exit(vp, sn);
return error;
}
/*
* Allow mapping of only D_DISK. This is called only for VBLK.
*/
int
spec_mmap(void *v)
{
struct vop_mmap_args /* {
struct vnode *a_vp;
vm_prot_t a_prot;
kauth_cred_t a_cred;
} */ *ap = v;
struct vnode *vp = ap->a_vp;
struct specnode *sn;
dev_t dev;
int error;
KASSERT(vp->v_type == VBLK);
error = spec_io_enter(vp, &sn, &dev);
if (error)
return error;
error = bdev_type(dev) == D_DISK ? 0 : EINVAL;
spec_io_exit(vp, sn);
return 0;
}
/*
* Synch buffers associated with a block device
*/
/* ARGSUSED */
int
spec_fsync(void *v)
{
struct vop_fsync_args /* {
struct vnode *a_vp;
kauth_cred_t a_cred;
int a_flags;
off_t offlo;
off_t offhi;
} */ *ap = v;
struct vnode *vp = ap->a_vp;
struct mount *mp;
int error;
/*
* This is a noop, simply returning what one has been given.
*/
int
spec_bmap(void *v)
{
struct vop_bmap_args /* {
struct vnode *a_vp;
daddr_t a_bn;
struct vnode **a_vpp;
daddr_t *a_bnp;
int *a_runp;
} */ *ap = v;
if (ap->a_vpp != NULL)
*ap->a_vpp = ap->a_vp;
if (ap->a_bnp != NULL)
*ap->a_bnp = ap->a_bn;
if (ap->a_runp != NULL)
*ap->a_runp = (MAXBSIZE >> DEV_BSHIFT) - 1;
return 0;
}
mutex_enter(vp->v_interlock);
sn = vp->v_specnode;
dev = vp->v_rdev;
sd = sn->sn_dev;
/*
* If we're going away soon, make this non-blocking.
* Also ensures that we won't wedge in vn_lock below.
*/
if (vdead_check(vp, VDEAD_NOWAIT) != 0)
flags |= FNONBLOCK;
mutex_exit(vp->v_interlock);
switch (vp->v_type) {
case VCHR:
/*
* Hack: a tty device that is a controlling terminal
* has a reference from the session structure. We
* cannot easily tell that a character device is a
* controlling terminal, unless it is the closing
* process' controlling terminal. In that case, if the
* open count is 1 release the reference from the
* session. Also, remove the link from the tty back to
* the session and pgrp.
*
* XXX V. fishy.
*/
mutex_enter(&proc_lock);
sess = curlwp->l_proc->p_session;
if (sn->sn_opencnt == 1 && vp == sess->s_ttyvp) {
mutex_spin_enter(&tty_lock);
sess->s_ttyvp = NULL;
if (sess->s_ttyp->t_session != NULL) {
sess->s_ttyp->t_pgrp = NULL;
sess->s_ttyp->t_session = NULL;
mutex_spin_exit(&tty_lock);
/* Releases proc_lock. */
proc_sessrele(sess);
} else {
mutex_spin_exit(&tty_lock);
if (sess->s_ttyp->t_pgrp != NULL)
panic("spec_close: spurious pgrp ref");
mutex_exit(&proc_lock);
}
vrele(vp);
} else
mutex_exit(&proc_lock);
/*
* If the vnode is locked, then we are in the midst
* of forcably closing the device, otherwise we only
* close on last reference.
*/
mode = S_IFCHR;
break;
case VBLK:
KASSERT(vp == vp->v_specnode->sn_dev->sd_bdevvp);
/*
* On last close of a block device (that isn't mounted)
* we must invalidate any in core blocks, so that
* we can, for instance, change floppy disks.
*/
error = vinvalbuf(vp, V_SAVE, ap->a_cred, curlwp, 0, 0);
if (error)
return error;
/*
* We do not want to really close the device if it
* is still in use unless we are trying to close it
* forcibly. Since every use (buffer, vnode, swap, cmap)
* holds a reference to the vnode, and because we mark
* any other vnodes that alias this device, when the
* sum of the reference counts on all the aliased
* vnodes descends to one, we are on last close.
*/
mode = S_IFBLK;
break;
default:
panic("spec_close: not special");
}
/*
* Decrement the open reference count of this node and the
* device. For block devices, the open reference count must be
* 1 at this point. If the device's open reference count goes
* to zero, we're the last one out so get the lights.
*
* We may find --sd->sd_opencnt gives zero, and yet
* sd->sd_opened is false. This happens if the vnode is
* revoked at the same time as it is being opened, which can
* happen when opening a tty blocks indefinitely. In that
* case, we still must call close -- it is the job of close to
* interrupt the open. Either way, the device will be no
* longer opened, so we have to clear sd->sd_opened; subsequent
* opens will have responsibility for issuing close.
*
* This has the side effect that the sequence of opens might
* happen out of order -- we might end up doing open, open,
* close, close, instead of open, close, open, close. This is
* unavoidable with the current devsw API, where open is
* allowed to block and close must be able to run concurrently
* to interrupt it. It is the driver's responsibility to
* ensure that close is idempotent so that this works. Drivers
* requiring per-open state and exact 1:1 correspondence
* between open and close can use fd_clone.
*/
mutex_enter(&device_lock);
KASSERT(sn->sn_opencnt);
KASSERT(sd->sd_opencnt);
KASSERTMSG(sn->sn_opencnt <= sd->sd_opencnt,
"sn_opencnt=%u > sd_opencnt=%u",
sn->sn_opencnt, sd->sd_opencnt);
sn->sn_opencnt--;
count = --sd->sd_opencnt;
if (vp->v_type == VBLK) {
KASSERTMSG(count == 0, "block device with %u opens",
count + 1);
sd->sd_bdevvp = NULL;
}
if (count == 0) {
KASSERTMSG(sn->sn_opencnt == 0, "sn_opencnt=%u",
sn->sn_opencnt);
KASSERT(!sd->sd_closing);
sd->sd_opened = false;
sd->sd_closing = true;
}
mutex_exit(&device_lock);
if (count != 0)
return 0;
/*
* If we're able to block, release the vnode lock & reacquire. We
* might end up sleeping for someone else who wants our queues. They
* won't get them if we hold the vnode locked.
*/
if (!(flags & FNONBLOCK))
VOP_UNLOCK(vp);
/*
* If we can cancel all outstanding I/O, then wait for it to
* drain before we call .d_close. Drivers that split up
* .d_cancel and .d_close this way need not have any internal
* mechanism for waiting in .d_close for I/O to drain.
*/
if (vp->v_type == VBLK)
error = bdev_cancel(dev, flags, mode, curlwp);
else
error = cdev_cancel(dev, flags, mode, curlwp);
if (error == 0)
spec_io_drain(sd);
else
KASSERTMSG(error == ENODEV, "cancel dev=0x%lx failed with %d",
(unsigned long)dev, error);
/*
* Wait for all other devsw operations to drain. After this
* point, no bdev/cdev_* can be active for this specdev.
*/
spec_io_drain(sd);
/*
* Wake any spec_open calls waiting for close to finish -- do
* this before reacquiring the vnode lock, because spec_open
* holds the vnode lock while waiting, so doing this after
* reacquiring the lock would deadlock.
*/
mutex_enter(&device_lock);
KASSERT(!sd->sd_opened);
KASSERT(sd->sd_closing);
sd->sd_closing = false;
cv_broadcast(&specfs_iocv);
mutex_exit(&device_lock);
if (!(flags & FNONBLOCK))
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
return error;
}
/*
* Print out the contents of a special device vnode.
*/
int
spec_print(void *v)
{
struct vop_print_args /* {
struct vnode *a_vp;
} */ *ap = v;
printf("dev %llu, %llu\n", (unsigned long long)major(ap->a_vp->v_rdev),
(unsigned long long)minor(ap->a_vp->v_rdev));
return 0;
}
/*
* Return POSIX pathconf information applicable to special devices.
*/
int
spec_pathconf(void *v)
{
struct vop_pathconf_args /* {
struct vnode *a_vp;
int a_name;
register_t *a_retval;
} */ *ap = v;
switch (ap->a_name) {
case _PC_LINK_MAX:
*ap->a_retval = LINK_MAX;
return 0;
case _PC_MAX_CANON:
*ap->a_retval = MAX_CANON;
return 0;
case _PC_MAX_INPUT:
*ap->a_retval = MAX_INPUT;
return 0;
case _PC_PIPE_BUF:
*ap->a_retval = PIPE_BUF;
return 0;
case _PC_CHOWN_RESTRICTED:
*ap->a_retval = 1;
return 0;
case _PC_VDISABLE:
*ap->a_retval = _POSIX_VDISABLE;
return 0;
case _PC_SYNC_IO:
*ap->a_retval = 1;
return 0;
default:
return genfs_pathconf(ap);
}
/* NOTREACHED */
}
/*
* Advisory record locking support.
*/
int
spec_advlock(void *v)
{
struct vop_advlock_args /* {
struct vnode *a_vp;
void *a_id;
int a_op;
struct flock *a_fl;
int a_flags;
} */ *ap = v;
struct vnode *vp = ap->a_vp;
