2 * Copyright (c) 1999 Michael Smith
4 * Copyright (c) 1999 Poul-Henning Kamp
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * $FreeBSD: src/sys/kern/vfs_conf.c,v 1.49.2.5 2003/01/07 11:56:53 joerg Exp $
29 * $DragonFly: src/sys/kern/vfs_conf.c,v 1.34 2008/05/24 19:08:28 dillon Exp $
33 * Locate and mount the root filesystem.
35 * The root filesystem is detailed in the kernel environment variable
36 * vfs.root.mountfrom, which is expected to be in the general format
39 * vfsname := the name of a VFS known to the kernel and capable
40 * of being mounted as root
41 * path := disk device name or other data used by the filesystem
42 * to locate its physical store
46 #include "opt_rootdevname.h"
48 #include <sys/param.h>
49 #include <sys/kernel.h>
50 #include <sys/systm.h>
52 #include <sys/vnode.h>
53 #include <sys/mount.h>
54 #include <sys/malloc.h>
55 #include <sys/reboot.h>
56 #include <sys/diskslice.h>
59 #include <sys/device.h>
61 #include <sys/namecache.h>
62 #include <sys/paths.h>
63 #include <sys/thread2.h>
64 #include <sys/nlookup.h>
65 #include <sys/devfs.h>
66 #include <sys/sysctl.h>
73 MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
75 #define ROOTNAME "root_device"
77 struct vnode *rootvnode;
78 struct nchandle rootnch;
81 * The root specifiers we will try if RB_CDROM is specified. Note that
82 * with DEVFS we do not use the compatibility slice's whole-disk 'c'
83 * partition. Instead we just use the whole disk, e.g. cd0 or cd0s0.
85 static char *cdrom_rootdevnames[] = {
86 "cd9660:cd0", /* SCSI (including AHCI and SILI) */
87 "cd9660:acd0", /* NATA */
88 "cd9660:cd1", /* SCSI (including AHCI and SILI) */
89 "cd9660:acd1", /* NATA */
90 "cd9660:cd8", /* USB */
91 "cd9660:cd9", /* USB */
95 int vfs_mountroot_devfs(void);
96 static void vfs_mountroot(void *junk);
97 static int vfs_mountroot_try(const char *mountfrom);
98 static int vfs_mountroot_ask(void);
99 static int getline(char *cp, int limit);
101 /* legacy find-root code */
102 char *rootdevnames[2] = {NULL, NULL};
103 static int setrootbyname(char *name);
105 SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL);
108 * Find and mount the root filesystem
111 vfs_mountroot(void *junk)
113 cdev_t save_rootdev = rootdev;
118 * Make sure all disk devices created so far have also been probed,
119 * and also make sure that the newly created device nodes for
120 * probed disks are ready, too.
122 * Messages can fly around here so get good synchronization
125 * XXX - Delay an additional 2 seconds to help drivers which pickup
126 * devices asynchronously and are not caught by CAM's initial
130 tsleep(&dummy, 0, "syncer", hz*2);
134 * The root filesystem information is compiled in, and we are
135 * booted with instructions to use it.
138 if ((boothowto & RB_DFLTROOT) &&
139 !vfs_mountroot_try(ROOTDEVNAME))
143 * We are booted with instructions to prompt for the root filesystem,
144 * or to use the compiled-in default when it doesn't exist.
146 if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
147 if (!vfs_mountroot_ask())
152 * We've been given the generic "use CDROM as root" flag. This is
153 * necessary because one media may be used in many different
154 * devices, so we need to search for them.
156 if (boothowto & RB_CDROM) {
157 for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
158 if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
164 * Try to use the value read by the loader from /etc/fstab, or
165 * supplied via some other means. This is the preferred
168 if (!vfs_mountroot_try(kgetenv("vfs.root.mountfrom")))
172 * If a vfs set rootdev, try it (XXX VINUM HACK!)
174 if (save_rootdev != NULL) {
175 rootdev = save_rootdev;
176 if (!vfs_mountroot_try(""))
181 * Try values that may have been computed by the machine-dependant
184 if (rootdevnames[0] && !vfs_mountroot_try(rootdevnames[0]))
186 if (rootdevnames[1] && !vfs_mountroot_try(rootdevnames[1]))
190 * If we have a compiled-in default, and haven't already tried it, try
194 if (!(boothowto & RB_DFLTROOT))
195 if (!vfs_mountroot_try(ROOTDEVNAME))
200 * Everything so far has failed, prompt on the console if we haven't
201 * already tried that.
203 if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
205 panic("Root mount failed, startup aborted.");
210 vfs_mountroot_devfs(void)
214 struct nlookupdata nd;
216 struct vfsconf *vfsp;
218 struct ucred *cred = proc0.p_ucred;
221 * Lookup the requested path and extract the nch and vnode.
223 error = nlookup_init_raw(&nd,
224 "/dev", UIO_SYSSPACE, NLC_FOLLOW,
228 devfs_debug(DEVFS_DEBUG_DEBUG, "vfs_mountroot_devfs: nlookup_init is ok...\n");
229 if ((error = nlookup(&nd)) == 0) {
230 devfs_debug(DEVFS_DEBUG_DEBUG, "vfs_mountroot_devfs: nlookup is ok...\n");
231 if (nd.nl_nch.ncp->nc_vp == NULL) {
232 devfs_debug(DEVFS_DEBUG_SHOW, "vfs_mountroot_devfs: nlookup: simply not found\n");
239 devfs_debug(DEVFS_DEBUG_SHOW, "vfs_mountroot_devfs: nlookup failed, error: %d\n", error);
244 * Extract the locked+refd ncp and cleanup the nd structure
247 cache_zero(&nd.nl_nch);
251 * now we have the locked ref'd nch and unreferenced vnode.
254 if ((error = vget(vp, LK_EXCLUSIVE)) != 0) {
256 devfs_debug(DEVFS_DEBUG_SHOW, "vfs_mountroot_devfs: vget failed\n");
261 if ((error = vinvalbuf(vp, V_SAVE, 0, 0)) != 0) {
264 devfs_debug(DEVFS_DEBUG_SHOW, "vfs_mountroot_devfs: vinvalbuf failed\n");
267 if (vp->v_type != VDIR) {
270 devfs_debug(DEVFS_DEBUG_SHOW, "vfs_mountroot_devfs: vp is not VDIR\n");
274 vfsp = vfsconf_find_by_name("devfs");
275 vsetflags(vp, VMOUNT);
278 * Allocate and initialize the filesystem.
280 mp = kmalloc(sizeof(struct mount), M_MOUNT, M_ZERO|M_WAITOK);
282 vfs_busy(mp, LK_NOWAIT);
283 mp->mnt_op = vfsp->vfc_vfsops;
285 vfsp->vfc_refcount++;
286 mp->mnt_stat.f_type = vfsp->vfc_typenum;
287 mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
288 strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
289 mp->mnt_stat.f_owner = cred->cr_uid;
293 * Mount the filesystem.
295 error = VFS_MOUNT(mp, "/dev", NULL, cred);
297 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
300 * Put the new filesystem on the mount list after root. The mount
301 * point gets its own mnt_ncmountpt (unless the VFS already set one
302 * up) which represents the root of the mount. The lookup code
303 * detects the mount point going forward and checks the root of
304 * the mount going backwards.
306 * It is not necessary to invalidate or purge the vnode underneath
307 * because elements under the mount will be given their own glue
311 if (mp->mnt_ncmountpt.ncp == NULL) {
313 * allocate, then unlock, but leave the ref intact
315 cache_allocroot(&mp->mnt_ncmountpt, mp, NULL);
316 cache_unlock(&mp->mnt_ncmountpt);
318 mp->mnt_ncmounton = nch; /* inherits ref */
319 nch.ncp->nc_flag |= NCF_ISMOUNTPT;
321 /* XXX get the root of the fs and cache_setvp(mnt_ncmountpt...) */
322 vclrflags(vp, VMOUNT);
323 mountlist_insert(mp, MNTINS_LAST);
325 //checkdirs(&mp->mnt_ncmounton, &mp->mnt_ncmountpt);
326 error = vfs_allocate_syncvnode(mp);
328 devfs_debug(DEVFS_DEBUG_SHOW, "vfs_mountroot_devfs: vfs_allocate_syncvnode failed\n");
331 error = VFS_START(mp, 0);
334 vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_coherency_ops);
335 vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_journal_ops);
336 vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_norm_ops);
337 vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_spec_ops);
338 vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_fifo_ops);
339 vclrflags(vp, VMOUNT);
340 mp->mnt_vfc->vfc_refcount--;
345 devfs_debug(DEVFS_DEBUG_SHOW, "vfs_mountroot_devfs: mount failed\n");
348 devfs_debug(DEVFS_DEBUG_DEBUG, "rootmount_devfs done with error: %d\n", error);
354 * Mount (mountfrom) as the root filesystem.
357 vfs_mountroot_try(const char *mountfrom)
359 struct mount *mp, *mp2;
360 char *vfsname, *devname;
363 int mountfromlen, len;
373 if (mountfrom == NULL)
374 return(error); /* don't complain */
377 kprintf("Mounting root from %s\n", mountfrom);
380 mountfromlen = strlen(mountfrom);
382 /* parse vfs name and devname */
383 vfsname = kmalloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
384 devname = kmalloc(MNAMELEN, M_MOUNT, M_WAITOK);
385 mf = kmalloc(MFSNAMELEN+MNAMELEN, M_MOUNT, M_WAITOK);
387 for (ep = cp; (*ep != 0) && (*ep != ';'); ep++);
389 bzero(vfsname, MFSNAMELEN);
390 bzero(devname, MNAMELEN);
391 bzero(mf, MFSNAMELEN+MNAMELEN);
392 strncpy(mf, cp, MFSNAMELEN+MNAMELEN);
394 vfsname[0] = devname[0] = 0;
395 ksprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
396 if (ksscanf(mf, patt, vfsname, devname) < 1)
399 /* allocate a root mount */
400 error = vfs_rootmountalloc(vfsname,
401 devname[0] != 0 ? devname : ROOTNAME, &mp);
403 kprintf("Can't allocate root mount for filesystem '%s': %d\n",
407 mp->mnt_flag |= MNT_ROOTFS;
409 /* do our best to set rootdev */
410 if ((strcmp(vfsname, "hammer") != 0) && (devname[0] != 0) &&
411 setrootbyname(devname))
412 kprintf("setrootbyname failed\n");
414 /* If the root device is a type "memory disk", mount RW */
415 if (rootdev != NULL && dev_is_good(rootdev) &&
416 (dev_dflags(rootdev) & D_MEMDISK)) {
417 mp->mnt_flag &= ~MNT_RDONLY;
420 error = VFS_MOUNT(mp, NULL, NULL, proc0.p_ucred);
431 kfree(vfsname, M_MOUNT);
433 kfree(devname, M_MOUNT);
437 /* register with list of mounted filesystems */
438 mountlist_insert(mp, MNTINS_FIRST);
440 /* sanity check system clock against root fs timestamp */
441 inittodr(mp->mnt_time);
443 if (mp->mnt_syncer == NULL) {
444 error = vfs_allocate_syncvnode(mp);
446 kprintf("Warning: no syncer vp for root!\n");
454 kprintf("Root mount failed: %d\n", error);
461 vfs_mountroot_ask_callback(cdev_t dev, void *arg __unused)
463 if (dev_is_good(dev) && (dev_dflags(dev) & D_DISK))
464 kprintf(" \"%s\" ", dev->si_name);
469 * Spin prompting on the console for a suitable root filesystem
472 vfs_mountroot_ask(void)
477 kprintf("\nManual root filesystem specification:\n");
478 kprintf(" <fstype>:<device> Specify root (e.g. ufs:da0s1a)\n");
479 kprintf(" ? List valid disk boot devices\n");
480 kprintf(" panic Just panic\n");
481 kprintf(" abort Abort manual input\n");
483 kprintf("\nmountroot> ");
485 if (getline(name, 128) < 0)
489 } else if (name[0] == '?') {
490 kprintf("Possibly valid devices for root FS:\n");
491 //enumerate all disk devices
492 devfs_scan_callback(vfs_mountroot_ask_callback, NULL);
495 } else if (strcmp(name, "panic") == 0) {
496 panic("panic from console");
497 } else if (strcmp(name, "abort") == 0) {
499 } else if (vfs_mountroot_try(name) == 0) {
508 getline(char *cp, int limit)
546 if (lp - cp >= limit - 1) {
558 * Convert a given name to the cdev_t of the disk-like device
570 kgetdiskbyname(const char *name)
576 * Get the base name of the device
578 if (strncmp(name, __SYS_PATH_DEV, sizeof(__SYS_PATH_DEV) - 1) == 0)
579 name += sizeof(__SYS_PATH_DEV) - 1;
580 cp = __DECONST(char *, name);
585 kprintf("tryroot %s\n", name);
586 rdev = devfs_find_device_by_name(name);
588 kprintf("no disk named '%s'\n", name);
597 * Set rootdev to match (name), given that we expect it to
598 * refer to a disk-like device.
601 setrootbyname(char *name)
605 diskdev = kgetdiskbyname(name);
606 if (diskdev != NULL) {
610 /* set to NULL if kgetdiskbyname() fails so that if the first rootdev is
611 * found by fails to mount and the second one isn't found, mountroot_try
612 * doesn't try again with the first one
619 DB_SHOW_COMMAND(disk, db_getdiskbyname)
623 if (modif[0] == '\0') {
624 db_error("usage: show disk/devicename");
627 dev = kgetdiskbyname(modif);
629 db_printf("cdev_t = %p\n", dev);
631 db_printf("No disk device matched.\n");
636 vfs_sysctl_real_root(SYSCTL_HANDLER_ARGS)
642 real_root = kgetenv("vfs.root.realroot");
644 if (real_root == NULL)
647 len = strlen(real_root) + 1;
649 error = sysctl_handle_string(oidp, real_root, len, req);
654 SYSCTL_PROC(_vfs, OID_AUTO, real_root,
655 CTLTYPE_STRING | CTLFLAG_RD, 0, 0, vfs_sysctl_real_root,
656 "A", "Real root mount string");