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freebsd-nq/sys/fs/specfs/spec_vnops.c
Poul-Henning Kamp ad3917e8e6 Do not attempt to open NODEV
2004-02-24 09:59:35 +00:00

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/*
* Copyright (c) 1989, 1993, 1995
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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 8.14 (Berkeley) 5/21/95
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/lock.h>
#include <sys/sx.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/mutex.h>
#include <sys/conf.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/stat.h>
#include <sys/fcntl.h>
#include <sys/vmmeter.h>
#include <sys/sysctl.h>
#include <sys/tty.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
static int spec_advlock(struct vop_advlock_args *);
static int spec_close(struct vop_close_args *);
static int spec_freeblks(struct vop_freeblks_args *);
static int spec_fsync(struct vop_fsync_args *);
static int spec_getpages(struct vop_getpages_args *);
static int spec_ioctl(struct vop_ioctl_args *);
static int spec_kqfilter(struct vop_kqfilter_args *);
static int spec_open(struct vop_open_args *);
static int spec_poll(struct vop_poll_args *);
static int spec_print(struct vop_print_args *);
static int spec_read(struct vop_read_args *);
static int spec_specstrategy(struct vop_specstrategy_args *);
static int spec_write(struct vop_write_args *);
vop_t **spec_vnodeop_p;
static struct vnodeopv_entry_desc spec_vnodeop_entries[] = {
{ &vop_default_desc, (vop_t *) vop_defaultop },
{ &vop_access_desc, (vop_t *) vop_ebadf },
{ &vop_advlock_desc, (vop_t *) spec_advlock },
{ &vop_bmap_desc, (vop_t *) vop_panic },
{ &vop_close_desc, (vop_t *) spec_close },
{ &vop_create_desc, (vop_t *) vop_panic },
{ &vop_freeblks_desc, (vop_t *) spec_freeblks },
{ &vop_fsync_desc, (vop_t *) spec_fsync },
{ &vop_getpages_desc, (vop_t *) spec_getpages },
{ &vop_getwritemount_desc, (vop_t *) vop_stdgetwritemount },
{ &vop_ioctl_desc, (vop_t *) spec_ioctl },
{ &vop_kqfilter_desc, (vop_t *) spec_kqfilter },
{ &vop_lease_desc, (vop_t *) vop_null },
{ &vop_link_desc, (vop_t *) vop_panic },
{ &vop_mkdir_desc, (vop_t *) vop_panic },
{ &vop_mknod_desc, (vop_t *) vop_panic },
{ &vop_open_desc, (vop_t *) spec_open },
{ &vop_pathconf_desc, (vop_t *) vop_stdpathconf },
{ &vop_poll_desc, (vop_t *) spec_poll },
{ &vop_print_desc, (vop_t *) spec_print },
{ &vop_read_desc, (vop_t *) spec_read },
{ &vop_readdir_desc, (vop_t *) vop_panic },
{ &vop_readlink_desc, (vop_t *) vop_panic },
{ &vop_reallocblks_desc, (vop_t *) vop_panic },
{ &vop_reclaim_desc, (vop_t *) vop_null },
{ &vop_remove_desc, (vop_t *) vop_panic },
{ &vop_rename_desc, (vop_t *) vop_panic },
{ &vop_rmdir_desc, (vop_t *) vop_panic },
{ &vop_setattr_desc, (vop_t *) vop_ebadf },
{ &vop_specstrategy_desc, (vop_t *) spec_specstrategy },
{ &vop_strategy_desc, (vop_t *) vop_panic },
{ &vop_symlink_desc, (vop_t *) vop_panic },
{ &vop_write_desc, (vop_t *) spec_write },
{ NULL, NULL }
};
static struct vnodeopv_desc spec_vnodeop_opv_desc =
{ &spec_vnodeop_p, spec_vnodeop_entries };
VNODEOP_SET(spec_vnodeop_opv_desc);
int
spec_vnoperate(ap)
struct vop_generic_args /* {
struct vnodeop_desc *a_desc;
<other random data follows, presumably>
} */ *ap;
{
return (VOCALL(spec_vnodeop_p, ap->a_desc->vdesc_offset, ap));
}
/*
* Open a special file.
*/
/* ARGSUSED */
static int
spec_open(ap)
struct vop_open_args /* {
struct vnode *a_vp;
int a_mode;
struct ucred *a_cred;
struct thread *a_td;
} */ *ap;
{
struct thread *td = ap->a_td;
struct vnode *vp = ap->a_vp;
dev_t dev = vp->v_rdev;
int error;
struct cdevsw *dsw;
if (vp->v_type == VBLK)
return (ENXIO);
/* Don't allow open if fs is mounted -nodev. */
if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_NODEV))
return (ENXIO);
if (dev == NODEV)
return (ENXIO);
dsw = devsw(dev);
if (dsw == NULL || dsw->d_open == NULL)
return (ENXIO);
/* Make this field valid before any I/O in d_open. */
if (dev->si_iosize_max == 0)
dev->si_iosize_max = DFLTPHYS;
/*
* XXX: Disks get special billing here, but it is mostly wrong.
* XXX: Disk partitions can overlap and the real checks should
* XXX: take this into account, and consequently they need to
* XXX: live in the disk slice code. Some checks do.
*/
if (vn_isdisk(vp, NULL) && ap->a_cred != FSCRED &&
(ap->a_mode & FWRITE)) {
/*
* Never allow opens for write if the disk is mounted R/W.
*/
if (vp->v_rdev->si_mountpoint != NULL &&
!(vp->v_rdev->si_mountpoint->mnt_flag & MNT_RDONLY))
return (EBUSY);
/*
* When running in secure mode, do not allow opens
* for writing if the disk is mounted.
*/
error = securelevel_ge(td->td_ucred, 1);
if (error && vfs_mountedon(vp))
return (error);
/*
* When running in very secure mode, do not allow
* opens for writing of any disks.
*/
error = securelevel_ge(td->td_ucred, 2);
if (error)
return (error);
}
/* XXX: Special casing of ttys for deadfs. Probably redundant. */
if (dsw->d_flags & D_TTY)
vp->v_vflag |= VV_ISTTY;
VOP_UNLOCK(vp, 0, td);
dev_ref(dev);
cdevsw_ref(dsw);
if(!(dsw->d_flags & D_NEEDGIANT)) {
DROP_GIANT();
if (dsw->d_fdopen != NULL)
error = dsw->d_fdopen(dev, ap->a_mode, td, ap->a_fdidx);
else
error = dsw->d_open(dev, ap->a_mode, S_IFCHR, td);
PICKUP_GIANT();
} else if (dsw->d_fdopen != NULL)
error = dsw->d_fdopen(dev, ap->a_mode, td, ap->a_fdidx);
else
error = dsw->d_open(dev, ap->a_mode, S_IFCHR, td);
cdevsw_rel(dsw);
if (error != 0)
dev_rel(dev);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
if (error)
return (error);
if (dsw->d_flags & D_TTY) {
if (dev->si_tty) {
struct tty *tp;
tp = dev->si_tty;
if (!tp->t_stop) {
printf("Warning:%s: no t_stop, using nottystop\n", devtoname(dev));
tp->t_stop = nottystop;
}
}
}
if (vn_isdisk(vp, NULL)) {
if (!dev->si_bsize_phys)
dev->si_bsize_phys = DEV_BSIZE;
}
return (error);
}
/*
* Vnode op for read
*/
/* ARGSUSED */
static int
spec_read(ap)
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
struct vnode *vp;
struct thread *td;
struct uio *uio;
dev_t dev;
int error, resid;
struct cdevsw *dsw;
vp = ap->a_vp;
dev = vp->v_rdev;
uio = ap->a_uio;
td = uio->uio_td;
resid = uio->uio_resid;
if (resid == 0)
return (0);
dsw = devsw(dev);
VOP_UNLOCK(vp, 0, td);
KASSERT(dev->si_refcount > 0,
("specread() on un-referenced dev_t (%s)", devtoname(dev)));
cdevsw_ref(dsw);
if (!(dsw->d_flags & D_NEEDGIANT)) {
DROP_GIANT();
error = dsw->d_read(dev, uio, ap->a_ioflag);
PICKUP_GIANT();
} else
error = dsw->d_read(dev, uio, ap->a_ioflag);
cdevsw_rel(dsw);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
if (uio->uio_resid != resid || (error == 0 && resid != 0))
vfs_timestamp(&dev->si_atime);
return (error);
}
/*
* Vnode op for write
*/
/* ARGSUSED */
static int
spec_write(ap)
struct vop_write_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
struct vnode *vp;
struct thread *td;
struct uio *uio;
dev_t dev;
int error, resid;
struct cdevsw *dsw;
vp = ap->a_vp;
dev = vp->v_rdev;
dsw = devsw(dev);
uio = ap->a_uio;
td = uio->uio_td;
resid = uio->uio_resid;
VOP_UNLOCK(vp, 0, td);
KASSERT(dev->si_refcount > 0,
("spec_write() on un-referenced dev_t (%s)", devtoname(dev)));
cdevsw_ref(dsw);
if (!(dsw->d_flags & D_NEEDGIANT)) {
DROP_GIANT();
error = dsw->d_write(dev, uio, ap->a_ioflag);
PICKUP_GIANT();
} else
error = dsw->d_write(dev, uio, ap->a_ioflag);
cdevsw_rel(dsw);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
if (uio->uio_resid != resid || (error == 0 && resid != 0)) {
vfs_timestamp(&dev->si_ctime);
dev->si_mtime = dev->si_ctime;
}
return (error);
}
/*
* Device ioctl operation.
*/
/* ARGSUSED */
static int
spec_ioctl(ap)
struct vop_ioctl_args /* {
struct vnode *a_vp;
u_long a_command;
caddr_t a_data;
int a_fflag;
struct ucred *a_cred;
struct thread *a_td;
} */ *ap;
{
dev_t dev;
int error;
struct cdevsw *dsw;
dev = ap->a_vp->v_rdev;
dsw = devsw(dev);
KASSERT(dev->si_refcount > 0,
("spec_ioctl() on un-referenced dev_t (%s)", devtoname(dev)));
cdevsw_ref(dsw);
if (!(dsw->d_flags & D_NEEDGIANT)) {
DROP_GIANT();
error = dsw->d_ioctl(dev, ap->a_command,
ap->a_data, ap->a_fflag, ap->a_td);
PICKUP_GIANT();
} else
error = dsw->d_ioctl(dev, ap->a_command,
ap->a_data, ap->a_fflag, ap->a_td);
cdevsw_rel(dsw);
if (error == ENOIOCTL)
error = ENOTTY;
return (error);
}
/* ARGSUSED */
static int
spec_poll(ap)
struct vop_poll_args /* {
struct vnode *a_vp;
int a_events;
struct ucred *a_cred;
struct thread *a_td;
} */ *ap;
{
dev_t dev;
struct cdevsw *dsw;
int error;
dev = ap->a_vp->v_rdev;
dsw = devsw(dev);
KASSERT(dev->si_refcount > 0,
("spec_poll() on un-referenced dev_t (%s)", devtoname(dev)));
cdevsw_ref(dsw);
if (!(dsw->d_flags & D_NEEDGIANT)) {
DROP_GIANT();
error = dsw->d_poll(dev, ap->a_events, ap->a_td);
PICKUP_GIANT();
} else
error = dsw->d_poll(dev, ap->a_events, ap->a_td);
cdevsw_rel(dsw);
return(error);
}
/* ARGSUSED */
static int
spec_kqfilter(ap)
struct vop_kqfilter_args /* {
struct vnode *a_vp;
struct knote *a_kn;
} */ *ap;
{
dev_t dev;
struct cdevsw *dsw;
int error;
dev = ap->a_vp->v_rdev;
dsw = devsw(dev);
KASSERT(dev->si_refcount > 0,
("spec_kqfilter() on un-referenced dev_t (%s)", devtoname(dev)));
cdevsw_ref(dsw);
if (!(dsw->d_flags & D_NEEDGIANT)) {
DROP_GIANT();
error = dsw->d_kqfilter(dev, ap->a_kn);
PICKUP_GIANT();
} else
error = dsw->d_kqfilter(dev, ap->a_kn);
cdevsw_rel(dsw);
return (error);
}
/*
* Synch buffers associated with a block device
*/
/* ARGSUSED */
static int
spec_fsync(ap)
struct vop_fsync_args /* {
struct vnode *a_vp;
struct ucred *a_cred;
int a_waitfor;
struct thread *a_td;
} */ *ap;
{
if (!vn_isdisk(ap->a_vp, NULL))
return (0);
return (vop_stdfsync(ap));
}
/*
* Mutex to use when delaying niced I/O bound processes in spec_strategy().
*/
static struct mtx strategy_mtx;
static void
strategy_init(void)
{
mtx_init(&strategy_mtx, "strategy", NULL, MTX_DEF);
}
SYSINIT(strategy, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, strategy_init, NULL)
static int doslowdown = 0;
SYSCTL_INT(_debug, OID_AUTO, doslowdown, CTLFLAG_RW, &doslowdown, 0, "");
/*
* Just call the device strategy routine
*/
static int
spec_xstrategy(struct vnode *vp, struct buf *bp)
{
struct mount *mp;
int error;
struct cdevsw *dsw;
struct thread *td = curthread;
KASSERT(bp->b_iocmd == BIO_READ ||
bp->b_iocmd == BIO_WRITE ||
bp->b_iocmd == BIO_DELETE,
("Wrong b_iocmd buf=%p cmd=%d", bp, bp->b_iocmd));
/*
* Slow down disk requests for niced processes.
*/
if (doslowdown && td && td->td_ksegrp->kg_nice > 0) {
mtx_lock(&strategy_mtx);
msleep(&strategy_mtx, &strategy_mtx,
PPAUSE | PCATCH | PDROP, "ioslow",
td->td_ksegrp->kg_nice);
}
if (bp->b_iocmd == BIO_WRITE) {
if ((bp->b_flags & B_VALIDSUSPWRT) == 0 &&
bp->b_vp != NULL && bp->b_vp->v_mount != NULL &&
(bp->b_vp->v_mount->mnt_kern_flag & MNTK_SUSPENDED) != 0)
panic("spec_strategy: bad I/O");
bp->b_flags &= ~B_VALIDSUSPWRT;
if (LIST_FIRST(&bp->b_dep) != NULL)
buf_start(bp);
mp_fixme("This should require the vnode lock.");
if ((vp->v_vflag & VV_COPYONWRITE) &&
vp->v_rdev->si_copyonwrite &&
(error = (*vp->v_rdev->si_copyonwrite)(vp, bp)) != 0 &&
error != EOPNOTSUPP) {
bp->b_io.bio_error = error;
bp->b_io.bio_flags |= BIO_ERROR;
biodone(&bp->b_io);
return (0);
}
}
/*
* Collect statistics on synchronous and asynchronous read
* and write counts for disks that have associated filesystems.
*/
if (vn_isdisk(vp, NULL) && (mp = vp->v_rdev->si_mountpoint) != NULL) {
if (bp->b_iocmd == BIO_WRITE) {
if (bp->b_lock.lk_lockholder == LK_KERNPROC)
mp->mnt_stat.f_asyncwrites++;
else
mp->mnt_stat.f_syncwrites++;
} else {
if (bp->b_lock.lk_lockholder == LK_KERNPROC)
mp->mnt_stat.f_asyncreads++;
else
mp->mnt_stat.f_syncreads++;
}
}
if (devsw(bp->b_dev) == NULL) {
bp->b_io.bio_error = ENXIO;
bp->b_io.bio_flags |= BIO_ERROR;
biodone(&bp->b_io);
return (0);
}
dsw = devsw(bp->b_dev);
KASSERT(dsw->d_strategy != NULL,
("No strategy on dev %s responsible for buffer %p\n",
devtoname(bp->b_dev), bp));
if (!(dsw->d_flags & D_NEEDGIANT)) {
/* XXX: notyet DROP_GIANT(); */
DEV_STRATEGY(bp);
/* XXX: notyet PICKUP_GIANT(); */
} else
DEV_STRATEGY(bp);
return (0);
}
static int
spec_specstrategy(ap)
struct vop_specstrategy_args /* {
struct vnode *a_vp;
struct buf *a_bp;
} */ *ap;
{
KASSERT(ap->a_vp->v_rdev == ap->a_bp->b_dev,
("%s, dev %s != %s", __func__,
devtoname(ap->a_vp->v_rdev),
devtoname(ap->a_bp->b_dev)));
return spec_xstrategy(ap->a_vp, ap->a_bp);
}
static int
spec_freeblks(ap)
struct vop_freeblks_args /* {
struct vnode *a_vp;
daddr_t a_addr;
daddr_t a_length;
} */ *ap;
{
struct buf *bp;
/*
* XXX: This assumes that strategy does the deed right away.
* XXX: this may not be TRTTD.
*/
if ((ap->a_vp->v_rdev->si_flags & SI_CANDELETE) == 0)
return (0);
bp = geteblk(ap->a_length);
bp->b_iocmd = BIO_DELETE;
bp->b_dev = ap->a_vp->v_rdev;
bp->b_blkno = ap->a_addr;
bp->b_offset = dbtob(ap->a_addr);
bp->b_iooffset = bp->b_offset;
bp->b_bcount = ap->a_length;
BUF_KERNPROC(bp);
DEV_STRATEGY(bp);
return (0);
}
/*
* Device close routine
*/
/* ARGSUSED */
static int
spec_close(ap)
struct vop_close_args /* {
struct vnode *a_vp;
int a_fflag;
struct ucred *a_cred;
struct thread *a_td;
} */ *ap;
{
struct vnode *vp = ap->a_vp, *oldvp;
struct thread *td = ap->a_td;
dev_t dev = vp->v_rdev;
struct cdevsw *dsw;
int error;
/*
* 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 reference count is 2 (this last descriptor
* plus the session), release the reference from the session.
*/
/*
* This needs to be rewritten to take the vp interlock into
* consideration.
*/
dsw = devsw(dev);
oldvp = NULL;
sx_xlock(&proctree_lock);
if (td && vp == td->td_proc->p_session->s_ttyvp) {
SESS_LOCK(td->td_proc->p_session);
VI_LOCK(vp);
if (vcount(vp) == 2 && (vp->v_iflag & VI_XLOCK) == 0) {
td->td_proc->p_session->s_ttyvp = NULL;
oldvp = vp;
}
VI_UNLOCK(vp);
SESS_UNLOCK(td->td_proc->p_session);
}
sx_xunlock(&proctree_lock);
if (oldvp != NULL)
vrele(oldvp);
/*
* 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.
*/
VI_LOCK(vp);
if (vp->v_iflag & VI_XLOCK) {
/* Forced close. */
} else if (dsw->d_flags & D_TRACKCLOSE) {
/* Keep device updated on status. */
} else if (vcount(vp) > 1) {
VI_UNLOCK(vp);
return (0);
}
VI_UNLOCK(vp);
KASSERT(dev->si_refcount > 0,
("spec_close() on un-referenced dev_t (%s)", devtoname(dev)));
cdevsw_ref(dsw);
if (!(dsw->d_flags & D_NEEDGIANT)) {
DROP_GIANT();
error = dsw->d_close(dev, ap->a_fflag, S_IFCHR, td);
PICKUP_GIANT();
} else
error = dsw->d_close(dev, ap->a_fflag, S_IFCHR, td);
cdevsw_rel(dsw);
dev_rel(dev);
return (error);
}
/*
* Print out the contents of a special device vnode.
*/
static int
spec_print(ap)
struct vop_print_args /* {
struct vnode *a_vp;
} */ *ap;
{
printf("\tdev %s\n", devtoname(ap->a_vp->v_rdev));
return (0);
}
/*
* Special device advisory byte-level locks.
*/
/* ARGSUSED */
static int
spec_advlock(ap)
struct vop_advlock_args /* {
struct vnode *a_vp;
caddr_t a_id;
int a_op;
struct flock *a_fl;
int a_flags;
} */ *ap;
{
return (ap->a_flags & F_FLOCK ? EOPNOTSUPP : EINVAL);
}
static int
spec_getpages(ap)
struct vop_getpages_args *ap;
{
vm_offset_t kva;
int error;
int i, pcount, size, s;
daddr_t blkno;
struct buf *bp;
vm_page_t m;
vm_ooffset_t offset;
int toff, nextoff, nread;
struct vnode *vp = ap->a_vp;
int blksiz;
int gotreqpage;
GIANT_REQUIRED;
error = 0;
pcount = round_page(ap->a_count) / PAGE_SIZE;
/*
* Calculate the offset of the transfer and do a sanity check.
* FreeBSD currently only supports an 8 TB range due to b_blkno
* being in DEV_BSIZE ( usually 512 ) byte chunks on call to
* VOP_STRATEGY. XXX
*/
offset = IDX_TO_OFF(ap->a_m[0]->pindex) + ap->a_offset;
blkno = btodb(offset);
/*
* Round up physical size for real devices. We cannot round using
* v_mount's block size data because v_mount has nothing to do with
* the device. i.e. it's usually '/dev'. We need the physical block
* size for the device itself.
*
* We can't use v_rdev->si_mountpoint because it only exists when the
* block device is mounted. However, we can use v_rdev.
*/
if (vn_isdisk(vp, NULL))
blksiz = vp->v_rdev->si_bsize_phys;
else
blksiz = DEV_BSIZE;
size = (ap->a_count + blksiz - 1) & ~(blksiz - 1);
bp = getpbuf(NULL);
kva = (vm_offset_t)bp->b_data;
/*
* Map the pages to be read into the kva.
*/
pmap_qenter(kva, ap->a_m, pcount);
/* Build a minimal buffer header. */
bp->b_iocmd = BIO_READ;
bp->b_iodone = bdone;
KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
bp->b_rcred = crhold(curthread->td_ucred);
bp->b_wcred = crhold(curthread->td_ucred);
bp->b_iooffset = offset;
bp->b_blkno = blkno;
bp->b_lblkno = blkno;
pbgetvp(ap->a_vp, bp);
bp->b_bcount = size;
bp->b_bufsize = size;
bp->b_resid = 0;
bp->b_runningbufspace = bp->b_bufsize;
runningbufspace += bp->b_runningbufspace;
cnt.v_vnodein++;
cnt.v_vnodepgsin += pcount;
/* Do the input. */
spec_xstrategy(bp->b_vp, bp);
s = splbio();
bwait(bp, PVM, "spread");
splx(s);
if ((bp->b_ioflags & BIO_ERROR) != 0) {
if (bp->b_error)
error = bp->b_error;
else
error = EIO;
}
nread = size - bp->b_resid;
if (nread < ap->a_count) {
bzero((caddr_t)kva + nread,
ap->a_count - nread);
}
pmap_qremove(kva, pcount);
gotreqpage = 0;
/*
* While the page is busy, its object field is immutable.
*/
VM_OBJECT_LOCK(ap->a_m[ap->a_reqpage]->object);
vm_page_lock_queues();
for (i = 0, toff = 0; i < pcount; i++, toff = nextoff) {
nextoff = toff + PAGE_SIZE;
m = ap->a_m[i];
m->flags &= ~PG_ZERO;
if (nextoff <= nread) {
m->valid = VM_PAGE_BITS_ALL;
vm_page_undirty(m);
} else if (toff < nread) {
/*
* Since this is a VM request, we have to supply the
* unaligned offset to allow vm_page_set_validclean()
* to zero sub-DEV_BSIZE'd portions of the page.
*/
vm_page_set_validclean(m, 0, nread - toff);
} else {
m->valid = 0;
vm_page_undirty(m);
}
if (i != ap->a_reqpage) {
/*
* Just in case someone was asking for this page we
* now tell them that it is ok to use.
*/
if (!error || (m->valid == VM_PAGE_BITS_ALL)) {
if (m->valid) {
if (m->flags & PG_WANTED) {
vm_page_activate(m);
} else {
vm_page_deactivate(m);
}
vm_page_wakeup(m);
} else {
vm_page_free(m);
}
} else {
vm_page_free(m);
}
} else if (m->valid) {
gotreqpage = 1;
/*
* Since this is a VM request, we need to make the
* entire page presentable by zeroing invalid sections.
*/
if (m->valid != VM_PAGE_BITS_ALL)
vm_page_zero_invalid(m, FALSE);
}
}
vm_page_unlock_queues();
if (!gotreqpage) {
m = ap->a_m[ap->a_reqpage];
printf(
"spec_getpages:(%s) I/O read failure: (error=%d) bp %p vp %p\n",
devtoname(bp->b_dev), error, bp, bp->b_vp);
printf(
" size: %d, resid: %ld, a_count: %d, valid: 0x%lx\n",
size, bp->b_resid, ap->a_count, (u_long)m->valid);
printf(
" nread: %d, reqpage: %d, pindex: %lu, pcount: %d\n",
nread, ap->a_reqpage, (u_long)m->pindex, pcount);
VM_OBJECT_UNLOCK(m->object);
/*
* Free the buffer header back to the swap buffer pool.
*/
relpbuf(bp, NULL);
return VM_PAGER_ERROR;
}
VM_OBJECT_UNLOCK(ap->a_m[ap->a_reqpage]->object);
/*
* Free the buffer header back to the swap buffer pool.
*/
relpbuf(bp, NULL);
return VM_PAGER_OK;
}
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