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Split the root mount logic from the (generic) mount code and move

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it (the root mount code) into a new file called vfs_mountroot.c

The split is almost trivial, as the code is almost perfectly
non-intertwined. The only adjustment needed was to move the UMA
zone allocation out of vfs_mountroot() [in vfs_mountroot.c] and
into vfs_mount.c, where it had to be done as a SYSINIT [see
vfs_mount_init()].

There are no functional changes with this commit.
This commit is contained in:
Marcel Moolenaar 2010-10-02 19:44:13 +00:00
parent de1add1e45
commit 24e01f5998
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=213365
3 changed files with 655 additions and 623 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
sys/conf/files
View File

@ -2264,6 +2264,7 @@ kern/vfs_hash.c standard
kern/vfs_init.c standard
kern/vfs_lookup.c standard
kern/vfs_mount.c standard
kern/vfs_mountroot.c standard
kern/vfs_subr.c standard
kern/vfs_syscalls.c standard
kern/vfs_vnops.c standard

651
sys/kern/vfs_mount.c
View File

@ -67,16 +67,10 @@ __FBSDID("$FreeBSD$");
#include <security/audit/audit.h>
#include <security/mac/mac_framework.h>
#include "opt_rootdevname.h"
#define ROOTNAME "root_device"
#define VFS_MOUNTARG_SIZE_MAX (1024 * 64)
static void set_rootvnode(void);
static int vfs_domount(struct thread *td, const char *fstype,
char *fspath, int fsflags, void *fsdata);
static int vfs_mountroot_ask(void);
static int vfs_mountroot_try(const char *mountfrom, const char *options);
static void free_mntarg(struct mntarg *ma);
static int usermount = 0;
@ -94,31 +88,6 @@ struct mntlist mountlist = TAILQ_HEAD_INITIALIZER(mountlist);
struct mtx mountlist_mtx;
MTX_SYSINIT(mountlist, &mountlist_mtx, "mountlist", MTX_DEF);
/*
* The vnode of the system's root (/ in the filesystem, without chroot
* active.)
*/
struct vnode *rootvnode;
/*
* The root filesystem is detailed in the kernel environment variable
* vfs.root.mountfrom, which is expected to be in the general format
*
* <vfsname>:[<path>][ <vfsname>:[<path>] ...]
* vfsname := the name of a VFS known to the kernel and capable
* of being mounted as root
* path := disk device name or other data used by the filesystem
* to locate its physical store
*
* If the environment variable vfs.root.mountfrom is a space separated list,
* each list element is tried in turn and the root filesystem will be mounted
* from the first one that suceeds.
*
* The environment variable vfs.root.mountfrom.options is a comma delimited
* set of string mount options. These mount options must be parseable
* by nmount() in the kernel.
*/
/*
* Global opts, taken by all filesystems
*/
@ -133,21 +102,35 @@ static const char *global_opts[] = {
NULL
};
/*
* The root specifiers we will try if RB_CDROM is specified.
*/
static char *cdrom_rootdevnames[] = {
"cd9660:cd0",
"cd9660:acd0",
NULL
};
static int
mount_init(void *mem, int size, int flags)
{
struct mount *mp;
/* legacy find-root code */
char *rootdevnames[2] = {NULL, NULL};
#ifndef ROOTDEVNAME
# define ROOTDEVNAME NULL
#endif
static const char *ctrootdevname = ROOTDEVNAME;
mp = (struct mount *)mem;
mtx_init(&mp->mnt_mtx, "struct mount mtx", NULL, MTX_DEF);
lockinit(&mp->mnt_explock, PVFS, "explock", 0, 0);
return (0);
}
static void
mount_fini(void *mem, int size)
{
struct mount *mp;
mp = (struct mount *)mem;
lockdestroy(&mp->mnt_explock);
mtx_destroy(&mp->mnt_mtx);
}
static void
vfs_mount_init(void *dummy __unused)
{
mount_zone = uma_zcreate("Mountpoints", sizeof(struct mount), NULL,
NULL, mount_init, mount_fini, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
}
SYSINIT(vfs_mount, SI_SUB_VFS, SI_ORDER_ANY, vfs_mount_init, NULL);
/*
* ---------------------------------------------------------------------
@ -452,27 +435,6 @@ vfs_rel(struct mount *mp)
MNT_IUNLOCK(mp);
}
static int
mount_init(void *mem, int size, int flags)
{
struct mount *mp;
mp = (struct mount *)mem;
mtx_init(&mp->mnt_mtx, "struct mount mtx", NULL, MTX_DEF);
lockinit(&mp->mnt_explock, PVFS, "explock", 0, 0);
return (0);
}
static void
mount_fini(void *mem, int size)
{
struct mount *mp;
mp = (struct mount *)mem;
lockdestroy(&mp->mnt_explock);
mtx_destroy(&mp->mnt_mtx);
}
/*
* Allocate and initialize the mount point struct.
*/
@ -1383,281 +1345,6 @@ dounmount(mp, flags, td)
return (0);
}
/*
* ---------------------------------------------------------------------
* Mounting of root filesystem
*
*/
struct root_hold_token {
const char *who;
LIST_ENTRY(root_hold_token) list;
};
static LIST_HEAD(, root_hold_token) root_holds =
LIST_HEAD_INITIALIZER(root_holds);
static int root_mount_complete;
/*
* Hold root mount.
*/
struct root_hold_token *
root_mount_hold(const char *identifier)
{
struct root_hold_token *h;
if (root_mounted())
return (NULL);
h = malloc(sizeof *h, M_DEVBUF, M_ZERO | M_WAITOK);
h->who = identifier;
mtx_lock(&mountlist_mtx);
LIST_INSERT_HEAD(&root_holds, h, list);
mtx_unlock(&mountlist_mtx);
return (h);
}
/*
* Release root mount.
*/
void
root_mount_rel(struct root_hold_token *h)
{
if (h == NULL)
return;
mtx_lock(&mountlist_mtx);
LIST_REMOVE(h, list);
wakeup(&root_holds);
mtx_unlock(&mountlist_mtx);
free(h, M_DEVBUF);
}
/*
* Wait for all subsystems to release root mount.
*/
static void
root_mount_prepare(void)
{
struct root_hold_token *h;
struct timeval lastfail;
int curfail = 0;
for (;;) {
DROP_GIANT();
g_waitidle();
PICKUP_GIANT();
mtx_lock(&mountlist_mtx);
if (LIST_EMPTY(&root_holds)) {
mtx_unlock(&mountlist_mtx);
break;
}
if (ppsratecheck(&lastfail, &curfail, 1)) {
printf("Root mount waiting for:");
LIST_FOREACH(h, &root_holds, list)
printf(" %s", h->who);
printf("\n");
}
msleep(&root_holds, &mountlist_mtx, PZERO | PDROP, "roothold",
hz);
}
}
/*
* Root was mounted, share the good news.
*/
static void
root_mount_done(void)
{
/* Keep prison0's root in sync with the global rootvnode. */
mtx_lock(&prison0.pr_mtx);
prison0.pr_root = rootvnode;
vref(prison0.pr_root);
mtx_unlock(&prison0.pr_mtx);
/*
* Use a mutex to prevent the wakeup being missed and waiting for
* an extra 1 second sleep.
*/
mtx_lock(&mountlist_mtx);
root_mount_complete = 1;
wakeup(&root_mount_complete);
mtx_unlock(&mountlist_mtx);
}
/*
* Return true if root is already mounted.
*/
int
root_mounted(void)
{
/* No mutex is acquired here because int stores are atomic. */
return (root_mount_complete);
}
/*
* Wait until root is mounted.
*/
void
root_mount_wait(void)
{
/*
* Panic on an obvious deadlock - the function can't be called from
* a thread which is doing the whole SYSINIT stuff.
*/
KASSERT(curthread->td_proc->p_pid != 0,
("root_mount_wait: cannot be called from the swapper thread"));
mtx_lock(&mountlist_mtx);
while (!root_mount_complete) {
msleep(&root_mount_complete, &mountlist_mtx, PZERO, "rootwait",
hz);
}
mtx_unlock(&mountlist_mtx);
}
static void
set_rootvnode()
{
struct proc *p;
if (VFS_ROOT(TAILQ_FIRST(&mountlist), LK_EXCLUSIVE, &rootvnode))
panic("Cannot find root vnode");
VOP_UNLOCK(rootvnode, 0);
p = curthread->td_proc;
FILEDESC_XLOCK(p->p_fd);
if (p->p_fd->fd_cdir != NULL)
vrele(p->p_fd->fd_cdir);
p->p_fd->fd_cdir = rootvnode;
VREF(rootvnode);
if (p->p_fd->fd_rdir != NULL)
vrele(p->p_fd->fd_rdir);
p->p_fd->fd_rdir = rootvnode;
VREF(rootvnode);
FILEDESC_XUNLOCK(p->p_fd);
EVENTHANDLER_INVOKE(mountroot);
}
/*
* Mount /devfs as our root filesystem, but do not put it on the mountlist
* yet. Create a /dev -> / symlink so that absolute pathnames will lookup.
*/
static void
devfs_first(void)
{
struct thread *td = curthread;
struct vfsoptlist *opts;
struct vfsconf *vfsp;
struct mount *mp = NULL;
int error;
vfsp = vfs_byname("devfs");
KASSERT(vfsp != NULL, ("Could not find devfs by name"));
if (vfsp == NULL)
return;
mp = vfs_mount_alloc(NULLVP, vfsp, "/dev", td->td_ucred);
error = VFS_MOUNT(mp);
KASSERT(error == 0, ("VFS_MOUNT(devfs) failed %d", error));
if (error)
return;
opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
TAILQ_INIT(opts);
mp->mnt_opt = opts;
mtx_lock(&mountlist_mtx);
TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
mtx_unlock(&mountlist_mtx);
set_rootvnode();
error = kern_symlink(td, "/", "dev", UIO_SYSSPACE);
if (error)
printf("kern_symlink /dev -> / returns %d\n", error);
}
/*
* Surgically move our devfs to be mounted on /dev.
*/
static void
devfs_fixup(struct thread *td)
{
struct nameidata nd;
struct vnode *vp, *dvp;
struct mount *mp;
int error;
/* Remove our devfs mount from the mountlist and purge the cache */
mtx_lock(&mountlist_mtx);
mp = TAILQ_FIRST(&mountlist);
TAILQ_REMOVE(&mountlist, mp, mnt_list);
mtx_unlock(&mountlist_mtx);
cache_purgevfs(mp);
VFS_ROOT(mp, LK_EXCLUSIVE, &dvp);
VI_LOCK(dvp);
dvp->v_iflag &= ~VI_MOUNT;
VI_UNLOCK(dvp);
dvp->v_mountedhere = NULL;
/* Set up the real rootvnode, and purge the cache */
TAILQ_FIRST(&mountlist)->mnt_vnodecovered = NULL;
set_rootvnode();
cache_purgevfs(rootvnode->v_mount);
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, "/dev", td);
error = namei(&nd);
if (error) {
printf("Lookup of /dev for devfs, error: %d\n", error);
vput(dvp);
vfs_unbusy(mp);
return;
}
NDFREE(&nd, NDF_ONLY_PNBUF);
vp = nd.ni_vp;
if (vp->v_type != VDIR) {
printf("/dev is not a directory\n");
vput(dvp);
vput(vp);
vfs_unbusy(mp);
return;
}
error = vinvalbuf(vp, V_SAVE, 0, 0);
if (error) {
printf("vinvalbuf() of /dev failed, error: %d\n", error);
vput(dvp);
vput(vp);
vfs_unbusy(mp);
return;
}
cache_purge(vp);
mp->mnt_vnodecovered = vp;
vp->v_mountedhere = mp;
mtx_lock(&mountlist_mtx);
TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
mtx_unlock(&mountlist_mtx);
VOP_UNLOCK(vp, 0);
vput(dvp);
vfs_unbusy(mp);
/* Unlink the no longer needed /dev/dev -> / symlink */
error = kern_unlink(td, "/dev/dev", UIO_SYSSPACE);
if (error)
printf("kern_unlink of /dev/dev failed, error: %d\n", error);
}
/*
* Report errors during filesystem mounting.
*/
@ -1694,288 +1381,6 @@ vfs_opterror(struct vfsoptlist *opts, const char *fmt, ...)
va_end(ap);
}
/*
* Find and mount the root filesystem
*/
void
vfs_mountroot(void)
{
char *cp, *cpt, *options, *tmpdev;
int error, i, asked = 0;
options = NULL;
root_mount_prepare();
mount_zone = uma_zcreate("Mountpoints", sizeof(struct mount),
NULL, NULL, mount_init, mount_fini,
UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
devfs_first();
/*
* We are booted with instructions to prompt for the root filesystem.
*/
if (boothowto & RB_ASKNAME) {
if (!vfs_mountroot_ask())
goto mounted;
asked = 1;
}
options = getenv("vfs.root.mountfrom.options");
/*
* The root filesystem information is compiled in, and we are
* booted with instructions to use it.
*/
if (ctrootdevname != NULL && (boothowto & RB_DFLTROOT)) {
if (!vfs_mountroot_try(ctrootdevname, options))
goto mounted;
ctrootdevname = NULL;
}
/*
* We've been given the generic "use CDROM as root" flag. This is
* necessary because one media may be used in many different
* devices, so we need to search for them.
*/
if (boothowto & RB_CDROM) {
for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
if (!vfs_mountroot_try(cdrom_rootdevnames[i], options))
goto mounted;
}
}
/*
* Try to use the value read by the loader from /etc/fstab, or
* supplied via some other means. This is the preferred
* mechanism.
*/
cp = getenv("vfs.root.mountfrom");
if (cp != NULL) {
cpt = cp;
while ((tmpdev = strsep(&cpt, " \t")) != NULL) {
error = vfs_mountroot_try(tmpdev, options);
if (error == 0) {
freeenv(cp);
goto mounted;
}
}
freeenv(cp);
}
/*
* Try values that may have been computed by code during boot
*/
if (!vfs_mountroot_try(rootdevnames[0], options))
goto mounted;
if (!vfs_mountroot_try(rootdevnames[1], options))
goto mounted;
/*
* If we (still) have a compiled-in default, try it.
*/
if (ctrootdevname != NULL)
if (!vfs_mountroot_try(ctrootdevname, options))
goto mounted;
/*
* Everything so far has failed, prompt on the console if we haven't
* already tried that.
*/
if (!asked)
if (!vfs_mountroot_ask())
goto mounted;
panic("Root mount failed, startup aborted.");
mounted:
root_mount_done();
freeenv(options);
}
static struct mntarg *
parse_mountroot_options(struct mntarg *ma, const char *options)
{
char *p;
char *name, *name_arg;
char *val, *val_arg;
char *opts;
if (options == NULL || options[0] == '\0')
return (ma);
p = opts = strdup(options, M_MOUNT);
if (opts == NULL) {
return (ma);
}
while((name = strsep(&p, ",")) != NULL) {
if (name[0] == '\0')
break;
val = strchr(name, '=');
if (val != NULL) {
*val = '\0';
++val;
}
if( strcmp(name, "rw") == 0 ||
strcmp(name, "noro") == 0) {
/*
* The first time we mount the root file system,
* we need to mount 'ro', so We need to ignore
* 'rw' and 'noro' mount options.
*/
continue;
}
name_arg = strdup(name, M_MOUNT);
val_arg = NULL;
if (val != NULL)
val_arg = strdup(val, M_MOUNT);
ma = mount_arg(ma, name_arg, val_arg,
(val_arg != NULL ? -1 : 0));
}
free(opts, M_MOUNT);
return (ma);
}
/*
* Mount (mountfrom) as the root filesystem.
*/
static int
vfs_mountroot_try(const char *mountfrom, const char *options)
{
struct mount *mp;
struct mntarg *ma;
char *vfsname, *path;
time_t timebase;
int error;
char patt[32];
char errmsg[255];
vfsname = NULL;
path = NULL;
mp = NULL;
ma = NULL;
error = EINVAL;
bzero(errmsg, sizeof(errmsg));
if (mountfrom == NULL)
return (error); /* don't complain */
printf("Trying to mount root from %s\n", mountfrom);
/* parse vfs name and path */
vfsname = malloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
path = malloc(MNAMELEN, M_MOUNT, M_WAITOK);
vfsname[0] = path[0] = 0;
sprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
if (sscanf(mountfrom, patt, vfsname, path) < 1)
goto out;
if (path[0] == '\0')
strcpy(path, ROOTNAME);
ma = mount_arg(ma, "fstype", vfsname, -1);
ma = mount_arg(ma, "fspath", "/", -1);
ma = mount_arg(ma, "from", path, -1);
ma = mount_arg(ma, "errmsg", errmsg, sizeof(errmsg));
ma = mount_arg(ma, "ro", NULL, 0);
ma = parse_mountroot_options(ma, options);
error = kernel_mount(ma, MNT_ROOTFS);
if (error == 0) {
/*
* We mount devfs prior to mounting the / FS, so the first
* entry will typically be devfs.
*/
mp = TAILQ_FIRST(&mountlist);
KASSERT(mp != NULL, ("%s: mountlist is empty", __func__));
/*
* Iterate over all currently mounted file systems and use
* the time stamp found to check and/or initialize the RTC.
* Typically devfs has no time stamp and the only other FS
* is the actual / FS.
* Call inittodr() only once and pass it the largest of the
* timestamps we encounter.
*/
timebase = 0;
do {
if (mp->mnt_time > timebase)
timebase = mp->mnt_time;
mp = TAILQ_NEXT(mp, mnt_list);
} while (mp != NULL);
inittodr(timebase);
devfs_fixup(curthread);
}
if (error != 0 ) {
printf("ROOT MOUNT ERROR: %s\n", errmsg);
printf("If you have invalid mount options, reboot, and ");
printf("first try the following from\n");
printf("the loader prompt:\n\n");
printf(" set vfs.root.mountfrom.options=rw\n\n");
printf("and then remove invalid mount options from ");
printf("/etc/fstab.\n\n");
}
out:
free(path, M_MOUNT);
free(vfsname, M_MOUNT);
return (error);
}
/*
* ---------------------------------------------------------------------
* Interactive root filesystem selection code.
*/
static int
vfs_mountroot_ask(void)
{
char name[128];
char *mountfrom;
char *options;
for(;;) {
printf("Loader variables:\n");
printf("vfs.root.mountfrom=");
mountfrom = getenv("vfs.root.mountfrom");
if (mountfrom != NULL) {
printf("%s", mountfrom);
}
printf("\n");
printf("vfs.root.mountfrom.options=");
options = getenv("vfs.root.mountfrom.options");
if (options != NULL) {
printf("%s", options);
}
printf("\n");
freeenv(mountfrom);
freeenv(options);
printf("\nManual root filesystem specification:\n");
printf(" <fstype>:<device> Mount <device> using filesystem <fstype>\n");
printf(" eg. zfs:tank\n");
printf(" eg. ufs:/dev/da0s1a\n");
printf(" eg. cd9660:/dev/acd0\n");
printf(" This is equivalent to: ");
printf("mount -t cd9660 /dev/acd0 /\n");
printf("\n");
printf(" ? List valid disk boot devices\n");
printf(" <empty line> Abort manual input\n");
printf("\nmountroot> ");
gets(name, sizeof(name), 1);
if (name[0] == '\0')
return (1);
if (name[0] == '?') {
printf("\nList of GEOM managed disk devices:\n ");
g_dev_print();
continue;
}
if (!vfs_mountroot_try(name, NULL))
return (0);
}
}
/*
* ---------------------------------------------------------------------
* Functions for querying mount options/arguments from filesystems.

626
sys/kern/vfs_mountroot.c Normal file
View File

@ -0,0 +1,626 @@
/*-
* Copyright (c) 1999-2004 Poul-Henning Kamp
* Copyright (c) 1999 Michael Smith
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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.
* 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 AUTHOR 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/libkern.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/namei.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/filedesc.h>
#include <sys/reboot.h>
#include <sys/syscallsubr.h>
#include <sys/sysproto.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <vm/uma.h>
#include <geom/geom.h>
#include <machine/stdarg.h>
#include "opt_rootdevname.h"
#define ROOTNAME "root_device"
static int vfs_mountroot_ask(void);
static int vfs_mountroot_try(const char *mountfrom, const char *options);
/*
* The vnode of the system's root (/ in the filesystem, without chroot
* active.)
*/
struct vnode *rootvnode;
/*
* The root filesystem is detailed in the kernel environment variable
* vfs.root.mountfrom, which is expected to be in the general format
*
* <vfsname>:[<path>][ <vfsname>:[<path>] ...]
* vfsname := the name of a VFS known to the kernel and capable
* of being mounted as root
* path := disk device name or other data used by the filesystem
* to locate its physical store
*
* If the environment variable vfs.root.mountfrom is a space separated list,
* each list element is tried in turn and the root filesystem will be mounted
* from the first one that suceeds.
*
* The environment variable vfs.root.mountfrom.options is a comma delimited
* set of string mount options. These mount options must be parseable
* by nmount() in the kernel.
*/
/*
* The root specifiers we will try if RB_CDROM is specified.
*/
static char *cdrom_rootdevnames[] = {
"cd9660:cd0",
"cd9660:acd0",
NULL
};
/* legacy find-root code */
char *rootdevnames[2] = {NULL, NULL};
#ifndef ROOTDEVNAME
# define ROOTDEVNAME NULL
#endif
static const char *ctrootdevname = ROOTDEVNAME;
struct root_hold_token {
const char *who;
LIST_ENTRY(root_hold_token) list;
};
static LIST_HEAD(, root_hold_token) root_holds =
LIST_HEAD_INITIALIZER(root_holds);
static int root_mount_complete;
struct root_hold_token *
root_mount_hold(const char *identifier)
{
struct root_hold_token *h;
if (root_mounted())
return (NULL);
h = malloc(sizeof *h, M_DEVBUF, M_ZERO | M_WAITOK);
h->who = identifier;
mtx_lock(&mountlist_mtx);
LIST_INSERT_HEAD(&root_holds, h, list);
mtx_unlock(&mountlist_mtx);
return (h);
}
void
root_mount_rel(struct root_hold_token *h)
{
if (h == NULL)
return;
mtx_lock(&mountlist_mtx);
LIST_REMOVE(h, list);
wakeup(&root_holds);
mtx_unlock(&mountlist_mtx);
free(h, M_DEVBUF);
}
static void
root_mount_prepare(void)
{
struct root_hold_token *h;
struct timeval lastfail;
int curfail = 0;
for (;;) {
DROP_GIANT();
g_waitidle();
PICKUP_GIANT();
mtx_lock(&mountlist_mtx);
if (LIST_EMPTY(&root_holds)) {
mtx_unlock(&mountlist_mtx);
break;
}
if (ppsratecheck(&lastfail, &curfail, 1)) {
printf("Root mount waiting for:");
LIST_FOREACH(h, &root_holds, list)
printf(" %s", h->who);
printf("\n");
}
msleep(&root_holds, &mountlist_mtx, PZERO | PDROP, "roothold",
hz);
}
}
static void
root_mount_done(void)
{
/* Keep prison0's root in sync with the global rootvnode. */
mtx_lock(&prison0.pr_mtx);
prison0.pr_root = rootvnode;
vref(prison0.pr_root);
mtx_unlock(&prison0.pr_mtx);
/*
* Use a mutex to prevent the wakeup being missed and waiting for
* an extra 1 second sleep.
*/
mtx_lock(&mountlist_mtx);
root_mount_complete = 1;
wakeup(&root_mount_complete);
mtx_unlock(&mountlist_mtx);
}
int
root_mounted(void)
{
/* No mutex is acquired here because int stores are atomic. */
return (root_mount_complete);
}
void
root_mount_wait(void)
{
/*
* Panic on an obvious deadlock - the function can't be called from
* a thread which is doing the whole SYSINIT stuff.
*/
KASSERT(curthread->td_proc->p_pid != 0,
("root_mount_wait: cannot be called from the swapper thread"));
mtx_lock(&mountlist_mtx);
while (!root_mount_complete) {
msleep(&root_mount_complete, &mountlist_mtx, PZERO, "rootwait",
hz);
}
mtx_unlock(&mountlist_mtx);
}
static void
set_rootvnode(void)
{
struct proc *p;
if (VFS_ROOT(TAILQ_FIRST(&mountlist), LK_EXCLUSIVE, &rootvnode))
panic("Cannot find root vnode");
VOP_UNLOCK(rootvnode, 0);
p = curthread->td_proc;
FILEDESC_XLOCK(p->p_fd);
if (p->p_fd->fd_cdir != NULL)
vrele(p->p_fd->fd_cdir);
p->p_fd->fd_cdir = rootvnode;
VREF(rootvnode);
if (p->p_fd->fd_rdir != NULL)
vrele(p->p_fd->fd_rdir);
p->p_fd->fd_rdir = rootvnode;
VREF(rootvnode);
FILEDESC_XUNLOCK(p->p_fd);
EVENTHANDLER_INVOKE(mountroot);
}
static void
devfs_first(void)
{
struct thread *td = curthread;
struct vfsoptlist *opts;
struct vfsconf *vfsp;
struct mount *mp = NULL;
int error;
vfsp = vfs_byname("devfs");
KASSERT(vfsp != NULL, ("Could not find devfs by name"));
if (vfsp == NULL)
return;
mp = vfs_mount_alloc(NULLVP, vfsp, "/dev", td->td_ucred);
error = VFS_MOUNT(mp);
KASSERT(error == 0, ("VFS_MOUNT(devfs) failed %d", error));
if (error)
return;
opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
TAILQ_INIT(opts);
mp->mnt_opt = opts;
mtx_lock(&mountlist_mtx);
TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
mtx_unlock(&mountlist_mtx);
set_rootvnode();
error = kern_symlink(td, "/", "dev", UIO_SYSSPACE);
if (error)
printf("kern_symlink /dev -> / returns %d\n", error);
}
static void
devfs_fixup(struct thread *td)
{
struct nameidata nd;
struct vnode *vp, *dvp;
struct mount *mp;
int error;
/* Remove our devfs mount from the mountlist and purge the cache */
mtx_lock(&mountlist_mtx);
mp = TAILQ_FIRST(&mountlist);
TAILQ_REMOVE(&mountlist, mp, mnt_list);
mtx_unlock(&mountlist_mtx);
cache_purgevfs(mp);
VFS_ROOT(mp, LK_EXCLUSIVE, &dvp);
VI_LOCK(dvp);
dvp->v_iflag &= ~VI_MOUNT;
VI_UNLOCK(dvp);
dvp->v_mountedhere = NULL;
/* Set up the real rootvnode, and purge the cache */
TAILQ_FIRST(&mountlist)->mnt_vnodecovered = NULL;
set_rootvnode();
cache_purgevfs(rootvnode->v_mount);
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, "/dev", td);
error = namei(&nd);
if (error) {
printf("Lookup of /dev for devfs, error: %d\n", error);
vput(dvp);
vfs_unbusy(mp);
return;
}
NDFREE(&nd, NDF_ONLY_PNBUF);
vp = nd.ni_vp;
if (vp->v_type != VDIR) {
printf("/dev is not a directory\n");
vput(dvp);
vput(vp);
vfs_unbusy(mp);
return;
}
error = vinvalbuf(vp, V_SAVE, 0, 0);
if (error) {
printf("vinvalbuf() of /dev failed, error: %d\n", error);
vput(dvp);
vput(vp);
vfs_unbusy(mp);
return;
}
cache_purge(vp);
mp->mnt_vnodecovered = vp;
vp->v_mountedhere = mp;
mtx_lock(&mountlist_mtx);
TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
mtx_unlock(&mountlist_mtx);
VOP_UNLOCK(vp, 0);
vput(dvp);
vfs_unbusy(mp);
/* Unlink the no longer needed /dev/dev -> / symlink */
error = kern_unlink(td, "/dev/dev", UIO_SYSSPACE);
if (error)
printf("kern_unlink of /dev/dev failed, error: %d\n", error);
}
void
vfs_mountroot(void)
{
char *cp, *cpt, *options, *tmpdev;
int error, i, asked = 0;
options = NULL;
root_mount_prepare();
devfs_first();
/*
* We are booted with instructions to prompt for the root filesystem.
*/
if (boothowto & RB_ASKNAME) {
if (!vfs_mountroot_ask())
goto mounted;
asked = 1;
}
options = getenv("vfs.root.mountfrom.options");
/*
* The root filesystem information is compiled in, and we are
* booted with instructions to use it.
*/
if (ctrootdevname != NULL && (boothowto & RB_DFLTROOT)) {
if (!vfs_mountroot_try(ctrootdevname, options))
goto mounted;
ctrootdevname = NULL;
}
/*
* We've been given the generic "use CDROM as root" flag. This is
* necessary because one media may be used in many different
* devices, so we need to search for them.
*/
if (boothowto & RB_CDROM) {
for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
if (!vfs_mountroot_try(cdrom_rootdevnames[i], options))
goto mounted;
}
}
/*
* Try to use the value read by the loader from /etc/fstab, or
* supplied via some other means. This is the preferred
* mechanism.
*/
cp = getenv("vfs.root.mountfrom");
if (cp != NULL) {
cpt = cp;
while ((tmpdev = strsep(&cpt, " \t")) != NULL) {
error = vfs_mountroot_try(tmpdev, options);
if (error == 0) {
freeenv(cp);
goto mounted;
}
}
freeenv(cp);
}
/*
* Try values that may have been computed by code during boot
*/
if (!vfs_mountroot_try(rootdevnames[0], options))
goto mounted;
if (!vfs_mountroot_try(rootdevnames[1], options))
goto mounted;
/*
* If we (still) have a compiled-in default, try it.
*/
if (ctrootdevname != NULL)
if (!vfs_mountroot_try(ctrootdevname, options))
goto mounted;
/*
* Everything so far has failed, prompt on the console if we haven't
* already tried that.
*/
if (!asked)
if (!vfs_mountroot_ask())
goto mounted;
panic("Root mount failed, startup aborted.");
mounted:
root_mount_done();
freeenv(options);
}
static struct mntarg *
parse_mountroot_options(struct mntarg *ma, const char *options)
{
char *p;
char *name, *name_arg;
char *val, *val_arg;
char *opts;
if (options == NULL || options[0] == '\0')
return (ma);
p = opts = strdup(options, M_MOUNT);
if (opts == NULL) {
return (ma);
}
while((name = strsep(&p, ",")) != NULL) {
if (name[0] == '\0')
break;
val = strchr(name, '=');
if (val != NULL) {
*val = '\0';
++val;
}
if( strcmp(name, "rw") == 0 ||
strcmp(name, "noro") == 0) {
/*
* The first time we mount the root file system,
* we need to mount 'ro', so We need to ignore
* 'rw' and 'noro' mount options.
*/
continue;
}
name_arg = strdup(name, M_MOUNT);
val_arg = NULL;
if (val != NULL)
val_arg = strdup(val, M_MOUNT);
ma = mount_arg(ma, name_arg, val_arg,
(val_arg != NULL ? -1 : 0));
}
free(opts, M_MOUNT);
return (ma);
}
/*
* Mount (mountfrom) as the root filesystem.
*/
static int
vfs_mountroot_try(const char *mountfrom, const char *options)
{
struct mount *mp;
struct mntarg *ma;
char *vfsname, *path;
time_t timebase;
int error;
char patt[32];
char errmsg[255];
vfsname = NULL;
path = NULL;
mp = NULL;
ma = NULL;
error = EINVAL;
bzero(errmsg, sizeof(errmsg));
if (mountfrom == NULL)
return (error); /* don't complain */
printf("Trying to mount root from %s\n", mountfrom);
/* parse vfs name and path */
vfsname = malloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
path = malloc(MNAMELEN, M_MOUNT, M_WAITOK);
vfsname[0] = path[0] = 0;
sprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
if (sscanf(mountfrom, patt, vfsname, path) < 1)
goto out;
if (path[0] == '\0')
strcpy(path, ROOTNAME);
ma = mount_arg(ma, "fstype", vfsname, -1);
ma = mount_arg(ma, "fspath", "/", -1);
ma = mount_arg(ma, "from", path, -1);
ma = mount_arg(ma, "errmsg", errmsg, sizeof(errmsg));
ma = mount_arg(ma, "ro", NULL, 0);
ma = parse_mountroot_options(ma, options);
error = kernel_mount(ma, MNT_ROOTFS);
if (error == 0) {
/*
* We mount devfs prior to mounting the / FS, so the first
* entry will typically be devfs.
*/
mp = TAILQ_FIRST(&mountlist);
KASSERT(mp != NULL, ("%s: mountlist is empty", __func__));
/*
* Iterate over all currently mounted file systems and use
* the time stamp found to check and/or initialize the RTC.
* Typically devfs has no time stamp and the only other FS
* is the actual / FS.
* Call inittodr() only once and pass it the largest of the
* timestamps we encounter.
*/
timebase = 0;
do {
if (mp->mnt_time > timebase)
timebase = mp->mnt_time;
mp = TAILQ_NEXT(mp, mnt_list);
} while (mp != NULL);
inittodr(timebase);
devfs_fixup(curthread);
}
if (error != 0 ) {
printf("ROOT MOUNT ERROR: %s\n", errmsg);
printf("If you have invalid mount options, reboot, and ");
printf("first try the following from\n");
printf("the loader prompt:\n\n");
printf(" set vfs.root.mountfrom.options=rw\n\n");
printf("and then remove invalid mount options from ");
printf("/etc/fstab.\n\n");
}
out:
free(path, M_MOUNT);
free(vfsname, M_MOUNT);
return (error);
}
static int
vfs_mountroot_ask(void)
{
char name[128];
char *mountfrom;
char *options;
for(;;) {
printf("Loader variables:\n");
printf("vfs.root.mountfrom=");
mountfrom = getenv("vfs.root.mountfrom");
if (mountfrom != NULL) {
printf("%s", mountfrom);
}
printf("\n");
printf("vfs.root.mountfrom.options=");
options = getenv("vfs.root.mountfrom.options");
if (options != NULL) {
printf("%s", options);
}
printf("\n");
freeenv(mountfrom);
freeenv(options);
printf("\nManual root filesystem specification:\n");
printf(" <fstype>:<device> Mount <device> using filesystem <fstype>\n");
printf(" eg. zfs:tank\n");
printf(" eg. ufs:/dev/da0s1a\n");
printf(" eg. cd9660:/dev/acd0\n");
printf(" This is equivalent to: ");
printf("mount -t cd9660 /dev/acd0 /\n");
printf("\n");
printf(" ? List valid disk boot devices\n");
printf(" <empty line> Abort manual input\n");
printf("\nmountroot> ");
gets(name, sizeof(name), 1);
if (name[0] == '\0')
return (1);
if (name[0] == '?') {
printf("\nList of GEOM managed disk devices:\n ");
g_dev_print();
continue;
}
if (!vfs_mountroot_try(name, NULL))
return (0);
}
}