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freebsd/sys/kern/kern_conf.c
KATO Takenori 81bca6ddae Clustered read and write are switched at mount-option level.
1. Clustered I/O is switched by the MNT_NOCLUSTERR and MNT_NOCLUSTERW
   bits of the mnt_flag.  The sysctl variables, vfs.foo.doclusterread
   and vfs.foo.doclusterwrite are deleted.  Only mount option can
   control clustered I/O from userland.
2. When foofs_mount mounts block device, foofs_mount checks D_CLUSTERR
   and D_CLUSTERW bits of the d_flags member in the block device switch
   table.  If D_NOCLUSTERR / D_NOCLUSTERW are set, MNT_NOCLUSTERR /
   MNT_NOCLUSTERW bits will be set.  In this case, MNT_NOCLUSTERR and
   MNT_NOCLUSTERW cannot be cleared from userland.
3. Vnode driver disables both clustered read and write.
4. Union filesystem disables clutered write.

Reviewed by:	bde
1997-09-27 13:40:20 +00:00

214 lines
5.6 KiB
C

/*-
* Parts Copyright (c) 1995 Terrence R. Lambert
* Copyright (c) 1995 Julian R. Elischer
* 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 Terrence R. Lambert.
* 4. The name Terrence R. Lambert may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY Julian R. Elischer ``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 TERRENCE R. LAMBERT 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.
*
* $Id: kern_conf.c,v 1.21 1997/09/21 22:20:12 julian Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/vnode.h>
#define NUMBDEV 128
#define NUMCDEV 256
#define bdevsw_ALLOCSTART (NUMBDEV/2)
#define cdevsw_ALLOCSTART (NUMCDEV/2)
struct bdevsw *bdevsw[NUMBDEV];
int nblkdev = NUMBDEV;
struct cdevsw *cdevsw[NUMCDEV];
int nchrdev = NUMCDEV;
/*
* Routine to determine if a device is a disk.
*
* KLUDGE XXX add flags to cdevsw entries for disks XXX
* A minimal stub routine can always return 0.
*/
int
isdisk(dev, type)
dev_t dev;
int type;
{
switch (major(dev)) {
case 15: /* VBLK: vn, VCHR: cd */
return (1);
case 0: /* wd */
case 2: /* fd */
case 4: /* sd */
case 6: /* cd */
case 7: /* mcd */
case 16: /* scd */
case 17: /* matcd */
case 18: /* ata */
case 19: /* wcd */
case 20: /* od */
case 22: /* gd */
if (type == VBLK)
return (1);
return (0);
case 3: /* wd */
case 9: /* fd */
case 13: /* sd */
case 29: /* mcd */
case 43: /* vn */
case 45: /* scd */
case 46: /* matcd */
case 69: /* wcd */
case 70: /* od */
case 78: /* gd */
if (type == VCHR)
return (1);
/* fall through */
default:
return (0);
}
/* NOTREACHED */
}
/*
* Routine to convert from character to block device number.
*
* A minimal stub routine can always return NODEV.
*/
dev_t
chrtoblk(dev_t dev)
{
struct bdevsw *bd;
struct cdevsw *cd;
if(cd = cdevsw[major(dev)]) {
if ( (bd = cd->d_bdev) )
return(makedev(bd->d_maj,minor(dev)));
}
return(NODEV);
}
/*
* (re)place an entry in the bdevsw or cdevsw table
* return the slot used in major(*descrip)
*/
#define ADDENTRY(TTYPE,NXXXDEV,ALLOCSTART) \
int TTYPE##_add(dev_t *descrip, \
struct TTYPE *newentry, \
struct TTYPE **oldentry) \
{ \
int i ; \
if ( (int)*descrip == NODEV) { /* auto (0 is valid) */ \
/* \
* Search the table looking for a slot... \
*/ \
for (i = ALLOCSTART; i < NXXXDEV; i++) \
if (TTYPE[i] == NULL) \
break; /* found one! */ \
/* out of allocable slots? */ \
if (i >= NXXXDEV) { \
return ENFILE; \
} \
} else { /* assign */ \
i = major(*descrip); \
if (i < 0 || i >= NXXXDEV) { \
return EINVAL; \
} \
} \
\
/* maybe save old */ \
if (oldentry) { \
*oldentry = TTYPE[i]; \
} \
if (newentry) \
newentry->d_maj = i; \
/* replace with new */ \
TTYPE[i] = newentry; \
\
/* done! let them know where we put it */ \
*descrip = makedev(i,0); \
return 0; \
} \
ADDENTRY(bdevsw, nblkdev,bdevsw_ALLOCSTART)
ADDENTRY(cdevsw, nchrdev,cdevsw_ALLOCSTART)
/*
* Since the bdevsw struct for a disk contains all the information
* needed to create a cdevsw entry, these two routines do that, rather
* than specifying it by hand.
*/
void
cdevsw_make(struct bdevsw *from)
{
struct cdevsw *to = from->d_cdev;
if (!to)
panic("No target cdevsw in bdevsw");
to->d_open = from->d_open;
to->d_close = from->d_close;
to->d_read = rawread;
to->d_write = rawwrite;
to->d_ioctl = from->d_ioctl;
to->d_stop = nostop;
to->d_reset = nullreset;
to->d_devtotty = nodevtotty;
to->d_poll = seltrue;
to->d_mmap = nommap;
to->d_strategy = from->d_strategy;
to->d_name = from->d_name;
to->d_bdev = from;
to->d_maj = -1;
}
void
bdevsw_add_generic(int bdev, int cdev, struct bdevsw *bdevsw)
{
dev_t dev;
/*
* XXX hack alert.
*/
if (isdisk(makedev(bdev, 0), VBLK) &&
(bdevsw->d_flags & D_TYPEMASK) != D_DISK) {
printf("bdevsw_add_generic: adding D_DISK flag for device %d\n",
bdev);
bdevsw->d_flags &= ~D_TYPEMASK;
bdevsw->d_flags |= D_DISK;
}
cdevsw_make(bdevsw);
dev = makedev(cdev, 0);
cdevsw_add(&dev, bdevsw->d_cdev, NULL);
dev = makedev(bdev, 0);
bdevsw_add(&dev, bdevsw , NULL);
}