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Introduce a force option, MD_FORCE, that instructs the driver to

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bypass some extra anti-foot-shooting measures.  Currently, its only
effect is to allow detaching a device while it's still open (e.g.,
mounted).  This is useful for testing how the system reacts to a disk
suddenly going away, which can happen with some removeable media.

At this point, the force option is only checked on detach, so it
would've been possible to allow the option to be passed with the
MDIOCDETACH operation.  This was not done to allow the possibility of
having the force flag influence other tests in the future, which may
not necessarily deal with detaching the device.

Reviewed by:	sobomax
Approved by:	phk
This commit is contained in:
Dima Dorfman 2001-08-07 19:23:16 +00:00
parent 5ebe32c611
commit 26a0ee75c6
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=81257
4 changed files with 15 additions and 2 deletions
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5
sbin/mdconfig/mdconfig.8
View File

@ -129,6 +129,11 @@ Enable clustering on this disk.
.Xc
Enable/Disable compression features to reduce memory usage.
.It Xo
.Oo Cm no Oc Ns Cm force
.Xc
Disable/Enable extra sanity checks to prevent the user from doing something
that might adversely affect the system.
.It Xo
.Oo Cm no Oc Ns Cm readonly
.Xc
Enable/Disable readonly mode.

4
sbin/mdconfig/mdconfig.c
View File

@ -120,6 +120,10 @@ main(int argc, char **argv)
mdio.md_options |= MD_COMPRESS;
else if (!strcmp(optarg, "nocompress"))
mdio.md_options &= ~MD_COMPRESS;
else if (!strcmp(optarg, "force"))
mdio.md_options |= MD_FORCE;
else if (!strcmp(optarg, "noforce"))
mdio.md_options &= ~MD_FORCE;
else if (!strcmp(optarg, "reserve"))
mdio.md_options |= MD_RESERVE;
else if (!strcmp(optarg, "noreserve"))

7
sys/dev/md/md.c
View File

@ -553,6 +553,7 @@ mdcreate_preload(struct md_ioctl *mdio)
sc->type = MD_PRELOAD;
sc->secsize = DEV_BSIZE;
sc->nsect = mdio->md_size;
sc->flags = mdio->md_options & MD_FORCE;
/* Cast to pointer size, then to pointer to avoid warning */
sc->pl_ptr = (u_char *)(uintptr_t)mdio->md_base;
sc->pl_len = (mdio->md_size << DEV_BSHIFT);
@ -587,7 +588,7 @@ mdcreate_malloc(struct md_ioctl *mdio)
sc->type = MD_MALLOC;
sc->secsize = DEV_BSIZE;
sc->nsect = mdio->md_size;
sc->flags = mdio->md_options & MD_COMPRESS;
sc->flags = mdio->md_options & (MD_COMPRESS | MD_FORCE);
MALLOC(sc->secp, u_char **, sc->nsect * sizeof(u_char *), M_MD, M_WAITOK | M_ZERO);
if (mdio->md_options & MD_RESERVE) {
for (u = 0; u < sc->nsect; u++)
@ -658,6 +659,7 @@ mdcreate_vnode(struct md_ioctl *mdio, struct proc *p)
return (EBUSY);
sc->type = MD_VNODE;
sc->flags = mdio->md_options & MD_FORCE;
flags = FREAD|FWRITE;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, mdio->md_file, p);
@ -776,6 +778,7 @@ mdcreate_swap(struct md_ioctl *mdio, struct proc *p)
sc->secsize = PAGE_SIZE;
sc->nsect = mdio->md_size / (PAGE_SIZE / DEV_BSIZE);
sc->object = vm_pager_allocate(OBJT_SWAP, NULL, sc->secsize * (vm_offset_t)sc->nsect, VM_PROT_DEFAULT, 0);
sc->flags = mdio->md_options & MD_FORCE;
if (mdio->md_options & MD_RESERVE) {
if (swap_pager_reserve(sc->object, 0, sc->nsect) < 0) {
vm_pager_deallocate(sc->object);
@ -827,7 +830,7 @@ mdctlioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct proc *p)
sc = mdfind(mdio->md_unit);
if (sc == NULL)
return (ENOENT);
if (sc->opencount != 0)
if (sc->opencount != 0 && !(sc->flags & MD_FORCE))
return (EBUSY);
switch(sc->type) {
case MD_VNODE:

1
sys/sys/mdioctl.h
View File

@ -84,5 +84,6 @@ struct md_ioctl {
#define MD_AUTOUNIT 0x04 /* Assign next free unit */
#define MD_READONLY 0x08 /* Readonly mode */
#define MD_COMPRESS 0x10 /* Compression mode */
#define MD_FORCE 0x20 /* Don't try to prevent foot-shooting */
#endif /* _SYS_MDIOCTL_H_*/