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Switch vfs_getvfs(), dounmount() and vfs_mountroot() to mountlist iterator.

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Add a helper to retrieve a mount with "highest generation < arg" and
use it from vfs_unmount_forceone() and vfs_unmountall1().
This commit is contained in:
hannken 2017-04-12 10:35:10 +00:00
parent 6058fea9b5
commit e08a8c4104
1 changed files with 62 additions and 32 deletions
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94
sys/kern/vfs_mount.c
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@ -1,4 +1,4 @@
/* $NetBSD: vfs_mount.c,v 1.52 2017/04/11 07:46:37 hannken Exp $ */
/* $NetBSD: vfs_mount.c,v 1.53 2017/04/12 10:35:10 hannken Exp $ */
/*-
* Copyright (c) 1997-2011 The NetBSD Foundation, Inc.
@ -67,7 +67,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_mount.c,v 1.52 2017/04/11 07:46:37 hannken Exp $");
__KERNEL_RCSID(0, "$NetBSD: vfs_mount.c,v 1.53 2017/04/12 10:35:10 hannken Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
@ -234,11 +234,9 @@ vfs_getnewfsid(struct mount *mp)
++xxxfs_mntid;
tfsid.__fsid_val[0] = makedev(mtype & 0xff, xxxfs_mntid);
tfsid.__fsid_val[1] = mtype;
if (!TAILQ_EMPTY(&mountlist)) {
while (vfs_getvfs(&tfsid)) {
tfsid.__fsid_val[0]++;
xxxfs_mntid++;
}
while (vfs_getvfs(&tfsid)) {
tfsid.__fsid_val[0]++;
xxxfs_mntid++;
}
mp->mnt_stat.f_fsidx.__fsid_val[0] = tfsid.__fsid_val[0];
mp->mnt_stat.f_fsid = mp->mnt_stat.f_fsidx.__fsid_val[0];
@ -253,17 +251,18 @@ vfs_getnewfsid(struct mount *mp)
struct mount *
vfs_getvfs(fsid_t *fsid)
{
mount_iterator_t *iter;
struct mount *mp;
mutex_enter(&mountlist_lock);
TAILQ_FOREACH(mp, &mountlist, mnt_list) {
mountlist_iterator_init(&iter);
while ((mp = mountlist_iterator_next(iter)) != NULL) {
if (mp->mnt_stat.f_fsidx.__fsid_val[0] == fsid->__fsid_val[0] &&
mp->mnt_stat.f_fsidx.__fsid_val[1] == fsid->__fsid_val[1]) {
mutex_exit(&mountlist_lock);
return (mp);
mountlist_iterator_destroy(iter);
return mp;
}
}
mutex_exit(&mountlist_lock);
mountlist_iterator_destroy(iter);
return NULL;
}
@ -832,6 +831,7 @@ err_unmounted:
int
dounmount(struct mount *mp, int flags, struct lwp *l)
{
mount_iterator_t *iter;
struct mount *cmp;
vnode_t *coveredvp;
int error, async, used_syncer, used_extattr;
@ -845,14 +845,14 @@ dounmount(struct mount *mp, int flags, struct lwp *l)
/*
* No unmount below layered mounts.
*/
mutex_enter(&mountlist_lock);
TAILQ_FOREACH(cmp, &mountlist, mnt_list) {
mountlist_iterator_init(&iter);
while ((cmp = mountlist_iterator_next(iter)) != NULL) {
if (cmp->mnt_lower == mp) {
mutex_exit(&mountlist_lock);
mountlist_iterator_destroy(iter);
return EBUSY;
}
}
mutex_exit(&mountlist_lock);
mountlist_iterator_destroy(iter);
/*
* XXX Freeze syncer. Must do this before locking the
@ -983,38 +983,57 @@ vfs_unmount_print(struct mount *mp, const char *pfx)
mp->mnt_stat.f_fstypename);
}
bool
vfs_unmount_forceone(struct lwp *l)
/*
* Return the mount with the highest generation less than "gen".
*/
static struct mount *
vfs_unmount_next(uint64_t gen)
{
mount_iterator_t *iter;
struct mount *mp, *nmp;
int error;
nmp = NULL;
TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) {
if (nmp == NULL || mp->mnt_gen > nmp->mnt_gen) {
mountlist_iterator_init(&iter);
while ((mp = mountlist_iterator_next(iter)) != NULL) {
if ((nmp == NULL || mp->mnt_gen > nmp->mnt_gen) &&
mp->mnt_gen < gen) {
if (nmp != NULL)
vfs_destroy(nmp);
nmp = mp;
atomic_inc_uint(&nmp->mnt_refcnt);
}
}
if (nmp == NULL) {
mountlist_iterator_destroy(iter);
return nmp;
}
bool
vfs_unmount_forceone(struct lwp *l)
{
struct mount *mp;
int error;
mp = vfs_unmount_next(mountgen);
if (mp == NULL) {
return false;
}
#ifdef DEBUG
printf("forcefully unmounting %s (%s)...\n",
nmp->mnt_stat.f_mntonname, nmp->mnt_stat.f_mntfromname);
mp->mnt_stat.f_mntonname, mp->mnt_stat.f_mntfromname);
#endif
atomic_inc_uint(&nmp->mnt_refcnt);
if ((error = dounmount(nmp, MNT_FORCE, l)) == 0) {
vfs_unmount_print(nmp, "forcefully ");
if ((error = dounmount(mp, MNT_FORCE, l)) == 0) {
vfs_unmount_print(mp, "forcefully ");
return true;
} else {
vfs_destroy(nmp);
vfs_destroy(mp);
}
#ifdef DEBUG
printf("forceful unmount of %s failed with error %d\n",
nmp->mnt_stat.f_mntonname, error);
mp->mnt_stat.f_mntonname, error);
#endif
return false;
@ -1023,17 +1042,23 @@ vfs_unmount_forceone(struct lwp *l)
bool
vfs_unmountall1(struct lwp *l, bool force, bool verbose)
{
struct mount *mp, *nmp;
struct mount *mp;
bool any_error = false, progress = false;
uint64_t gen;
int error;
TAILQ_FOREACH_REVERSE_SAFE(mp, &mountlist, mntlist, mnt_list, nmp) {
gen = mountgen;
for (;;) {
mp = vfs_unmount_next(gen);
if (mp == NULL)
break;
gen = mp->mnt_gen;
#ifdef DEBUG
printf("unmounting %p %s (%s)...\n",
(void *)mp, mp->mnt_stat.f_mntonname,
mp->mnt_stat.f_mntfromname);
#endif
atomic_inc_uint(&mp->mnt_refcnt);
if ((error = dounmount(mp, force ? MNT_FORCE : 0, l)) == 0) {
vfs_unmount_print(mp, "");
progress = true;
@ -1229,10 +1254,15 @@ done:
vrele(rootvp);
}
if (error == 0) {
mount_iterator_t *iter;
struct mount *mp;
extern struct cwdinfo cwdi0;
mp = TAILQ_FIRST(&mountlist);
mountlist_iterator_init(&iter);
mp = mountlist_iterator_next(iter);
KASSERT(mp != NULL);
mountlist_iterator_destroy(iter);
mp->mnt_flag |= MNT_ROOTFS;
mp->mnt_op->vfs_refcount++;
error = fstrans_mount(mp);