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[/] [or1k/] [trunk/] [uclinux/] [uClinux-2.0.x/] [fs/] [super.c] - Blame information for rev 199

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/*
 *  linux/fs/super.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  super.c contains code to handle: - mount structures
 *                                   - super-block tables.
 *                                   - mount systemcall
 *                                   - umount systemcall
 *
 *  Added options to /proc/mounts
 *  Torbj�rn Lindh (torbjorn.lindh@gopta.se), April 14, 1996.
 *
 * GK 2/5/95  -  Changed to support mounting the root fs via NFS
 *
 *  Added kerneld support: Jacques Gelinas and Bjorn Ekwall
 *  Added change_root: Werner Almesberger & Hans Lermen, Feb '96
 */
 
/*
 * uClinux revisions for NO_MM
 * Copyright (C) 1998  Kenneth Albanowski <kjahds@kjahds.com>,
 *                     The Silver Hammer Group, Ltd.
 */
 
#include <stdarg.h>
 
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mount.h>
#include <linux/malloc.h>
#include <linux/major.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/locks.h>
#include <linux/mm.h>
#include <linux/fd.h>
 
#include <asm/system.h>
#include <asm/segment.h>
#include <asm/bitops.h>
 
#ifdef CONFIG_KERNELD
#include <linux/kerneld.h>
#endif
 
#include <linux/nfs_fs.h>
#include <linux/nfs_fs_sb.h>
#include <linux/nfs_mount.h>
 
extern void wait_for_keypress(void);
extern struct file_operations * get_blkfops(unsigned int major);
extern void blkdev_release (struct inode *);
extern void rd_load_secondary(void);
 
extern int root_mountflags;
 
static int do_remount_sb(struct super_block *sb, int flags, char * data);
 
/* this is initialized in init/main.c */
kdev_t ROOT_DEV;
 
struct super_block super_blocks[NR_SUPER];
static struct file_system_type *file_systems = (struct file_system_type *) NULL;
static struct vfsmount *vfsmntlist = (struct vfsmount *) NULL,
                       *vfsmnttail = (struct vfsmount *) NULL,
                       *mru_vfsmnt = (struct vfsmount *) NULL;
 
/*
 * This part handles the management of the list of mounted filesystems.
 */
struct vfsmount *lookup_vfsmnt(kdev_t dev)
{
        struct vfsmount *lptr;
 
        if (vfsmntlist == (struct vfsmount *)NULL)
                return ((struct vfsmount *)NULL);
 
        if (mru_vfsmnt != (struct vfsmount *)NULL &&
            mru_vfsmnt->mnt_dev == dev)
                return (mru_vfsmnt);
 
        for (lptr = vfsmntlist;
             lptr != (struct vfsmount *)NULL;
             lptr = lptr->mnt_next)
                if (lptr->mnt_dev == dev) {
                        mru_vfsmnt = lptr;
                        return (lptr);
                }
 
        return ((struct vfsmount *)NULL);
        /* NOTREACHED */
}
 
struct vfsmount *add_vfsmnt(kdev_t dev, const char *dev_name, const char *dir_name)
{
        struct vfsmount *lptr;
        char *tmp;
 
        lptr = (struct vfsmount *)kmalloc(sizeof(struct vfsmount), GFP_KERNEL);
        if (!lptr)
                return NULL;
        memset(lptr, 0, sizeof(struct vfsmount));
 
        lptr->mnt_dev = dev;
        lptr->mnt_sem.count = 1;
        if (dev_name && !getname(dev_name, &tmp)) {
                if ((lptr->mnt_devname =
                    (char *) kmalloc(strlen(tmp)+1, GFP_KERNEL)) != (char *)NULL)
                        strcpy(lptr->mnt_devname, tmp);
                putname(tmp);
        }
        if (dir_name && !getname(dir_name, &tmp)) {
                if ((lptr->mnt_dirname =
                    (char *) kmalloc(strlen(tmp)+1, GFP_KERNEL)) != (char *)NULL)
                        strcpy(lptr->mnt_dirname, tmp);
                putname(tmp);
        }
 
        if (vfsmntlist == (struct vfsmount *)NULL) {
                vfsmntlist = vfsmnttail = lptr;
        } else {
                vfsmnttail->mnt_next = lptr;
                vfsmnttail = lptr;
        }
        return (lptr);
}
 
void remove_vfsmnt(kdev_t dev)
{
        struct vfsmount *lptr, *tofree;
 
        if (vfsmntlist == (struct vfsmount *)NULL)
                return;
        lptr = vfsmntlist;
        if (lptr->mnt_dev == dev) {
                tofree = lptr;
                vfsmntlist = lptr->mnt_next;
                if (vfsmnttail->mnt_dev == dev)
                        vfsmnttail = vfsmntlist;
        } else {
                while (lptr->mnt_next != (struct vfsmount *)NULL) {
                        if (lptr->mnt_next->mnt_dev == dev)
                                break;
                        lptr = lptr->mnt_next;
                }
                tofree = lptr->mnt_next;
                if (tofree == (struct vfsmount *)NULL)
                        return;
                lptr->mnt_next = lptr->mnt_next->mnt_next;
                if (vfsmnttail->mnt_dev == dev)
                        vfsmnttail = lptr;
        }
        if (tofree == mru_vfsmnt)
                mru_vfsmnt = NULL;
        kfree(tofree->mnt_devname);
        kfree(tofree->mnt_dirname);
        kfree_s(tofree, sizeof(struct vfsmount));
}
 
int register_filesystem(struct file_system_type * fs)
{
        struct file_system_type ** tmp;
 
        if (!fs)
                return -EINVAL;
        if (fs->next)
                return -EBUSY;
        tmp = &file_systems;
        while (*tmp) {
                if (strcmp((*tmp)->name, fs->name) == 0)
                        return -EBUSY;
                tmp = &(*tmp)->next;
        }
        *tmp = fs;
        return 0;
}
 
#ifdef CONFIG_MODULES
int unregister_filesystem(struct file_system_type * fs)
{
        struct file_system_type ** tmp;
 
        tmp = &file_systems;
        while (*tmp) {
                if (fs == *tmp) {
                        *tmp = fs->next;
                        fs->next = NULL;
                        return 0;
                }
                tmp = &(*tmp)->next;
        }
        return -EINVAL;
}
#endif
 
static int fs_index(const char * __name)
{
        struct file_system_type * tmp;
        char * name;
        int err, index;
 
        err = getname(__name, &name);
        if (err)
                return err;
        index = 0;
        for (tmp = file_systems ; tmp ; tmp = tmp->next) {
                if (strcmp(tmp->name, name) == 0) {
                        putname(name);
                        return index;
                }
                index++;
        }
        putname(name);
        return -EINVAL;
}
 
static int fs_name(unsigned int index, char * buf)
{
        struct file_system_type * tmp;
        int err, len;
 
        tmp = file_systems;
        while (tmp && index > 0) {
                tmp = tmp->next;
                index--;
        }
        if (!tmp)
                return -EINVAL;
        len = strlen(tmp->name) + 1;
        err = verify_area(VERIFY_WRITE, buf, len);
        if (err)
                return err;
        memcpy_tofs(buf, tmp->name, len);
        return 0;
}
 
static int fs_maxindex(void)
{
        struct file_system_type * tmp;
        int index;
 
        index = 0;
        for (tmp = file_systems ; tmp ; tmp = tmp->next)
                index++;
        return index;
}
 
/*
 * Whee.. Weird sysv syscall.
 */
asmlinkage int sys_sysfs(int option, ...)
{
        va_list args;
        int retval = -EINVAL;
        unsigned int index;
 
        va_start(args, option);
        switch (option) {
                case 1:
                        retval = fs_index(va_arg(args, const char *));
                        break;
 
                case 2:
                        index = va_arg(args, unsigned int);
                        retval = fs_name(index, va_arg(args, char *));
                        break;
 
                case 3:
                        retval = fs_maxindex();
                        break;
        }
        va_end(args);
        return retval;
}
 
static struct proc_fs_info {
        int flag;
        char *str;
} fs_info[] = {
        { MS_NOEXEC, ",noexec" },
        { MS_NOSUID, ",nosuid" },
        { MS_NODEV, ",nodev" },
        { MS_SYNCHRONOUS, ",sync" },
        { MS_MANDLOCK, ",mand" },
        { MS_NOATIME, ",noatime" },
#ifdef MS_NOSUB                 /* Can't find this except in mount.c */
        { MS_NOSUB, ",nosub" },
#endif
        { 0, NULL }
};
 
static struct proc_nfs_info {
        int flag;
        char *str;
} nfs_info[] = {
        { NFS_MOUNT_SOFT, ",soft" },
        { NFS_MOUNT_INTR, ",intr" },
        { NFS_MOUNT_POSIX, ",posix" },
        { NFS_MOUNT_NOCTO, ",nocto" },
        { NFS_MOUNT_NOAC, ",noac" },
        { 0, NULL }
};
 
int get_filesystem_info( char *buf )
{
        struct vfsmount *tmp = vfsmntlist;
        struct proc_fs_info *fs_infop;
        struct proc_nfs_info *nfs_infop;
        struct nfs_server *nfss;
        int len = 0;
 
        while ( tmp && len < PAGE_SIZE - 160)
        {
                len += sprintf( buf + len, "%s %s %s %s",
                        tmp->mnt_devname, tmp->mnt_dirname, tmp->mnt_sb->s_type->name,
                        tmp->mnt_flags & MS_RDONLY ? "ro" : "rw" );
                for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
                  if (tmp->mnt_flags & fs_infop->flag) {
                    strcpy(buf + len, fs_infop->str);
                    len += strlen(fs_infop->str);
                  }
                }
                if (!strcmp("nfs", tmp->mnt_sb->s_type->name)) {
                        nfss = &tmp->mnt_sb->u.nfs_sb.s_server;
                        if (nfss->rsize != NFS_DEF_FILE_IO_BUFFER_SIZE) {
                                len += sprintf(buf+len, ",rsize=%d",
                                               nfss->rsize);
                        }
                        if (nfss->wsize != NFS_DEF_FILE_IO_BUFFER_SIZE) {
                                len += sprintf(buf+len, ",wsize=%d",
                                               nfss->wsize);
                        }
                        if (nfss->timeo != 7*HZ/10) {
                                len += sprintf(buf+len, ",timeo=%d",
                                               nfss->timeo*10/HZ);
                        }
                        if (nfss->retrans != 3) {
                                len += sprintf(buf+len, ",retrans=%d",
                                               nfss->retrans);
                        }
                        if (nfss->acregmin != 3*HZ) {
                                len += sprintf(buf+len, ",acregmin=%d",
                                               nfss->acregmin/HZ);
                        }
                        if (nfss->acregmax != 60*HZ) {
                                len += sprintf(buf+len, ",acregmax=%d",
                                               nfss->acregmax/HZ);
                        }
                        if (nfss->acdirmin != 30*HZ) {
                                len += sprintf(buf+len, ",acdirmin=%d",
                                               nfss->acdirmin/HZ);
                        }
                        if (nfss->acdirmax != 60*HZ) {
                                len += sprintf(buf+len, ",acdirmax=%d",
                                               nfss->acdirmax/HZ);
                        }
                        for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
                                if (nfss->flags & nfs_infop->flag) {
                                        strcpy(buf + len, nfs_infop->str);
                                        len += strlen(nfs_infop->str);
                                }
                        }
                        len += sprintf(buf+len, ",addr=%s",
                                       nfss->hostname);
                }
                len += sprintf( buf + len, " 0 0\n" );
                tmp = tmp->mnt_next;
        }
 
        return len;
}
 
int get_filesystem_list(char * buf)
{
        int len = 0;
        struct file_system_type * tmp;
 
        tmp = file_systems;
        while (tmp && len < PAGE_SIZE - 80) {
                len += sprintf(buf+len, "%s\t%s\n",
                        tmp->requires_dev ? "" : "nodev",
                        tmp->name);
                tmp = tmp->next;
        }
        return len;
}
 
struct file_system_type *get_fs_type(const char *name)
{
        struct file_system_type * fs = file_systems;
 
        if (!name)
                return fs;
        for (fs = file_systems; fs && strcmp(fs->name, name); fs = fs->next)
                ;
#ifdef CONFIG_KERNELD
        if (!fs && (request_module(name) == 0)) {
                for (fs = file_systems; fs && strcmp(fs->name, name); fs = fs->next)
                        ;
        }
#endif
 
        return fs;
}
 
void __wait_on_super(struct super_block * sb)
{
        struct wait_queue wait = { current, NULL };
 
        add_wait_queue(&sb->s_wait, &wait);
repeat:
        current->state = TASK_UNINTERRUPTIBLE;
        if (sb->s_lock) {
                schedule();
                goto repeat;
        }
        remove_wait_queue(&sb->s_wait, &wait);
        current->state = TASK_RUNNING;
}
 
void sync_supers(kdev_t dev)
{
        struct super_block * sb;
 
        for (sb = super_blocks + 0 ; sb < super_blocks + NR_SUPER ; sb++) {
                if (!sb->s_dev)
                        continue;
                if (dev && sb->s_dev != dev)
                        continue;
                wait_on_super(sb);
                if (!sb->s_dev || !sb->s_dirt)
                        continue;
                if (dev && (dev != sb->s_dev))
                        continue;
                if (sb->s_op && sb->s_op->write_super)
                        sb->s_op->write_super(sb);
        }
}
 
static struct super_block * get_super(kdev_t dev)
{
        struct super_block * s;
 
        if (!dev)
                return NULL;
        s = 0+super_blocks;
        while (s < NR_SUPER+super_blocks)
                if (s->s_dev == dev) {
                        wait_on_super(s);
                        if (s->s_dev == dev)
                                return s;
                        s = 0+super_blocks;
                } else
                        s++;
        return NULL;
}
 
void put_super(kdev_t dev)
{
        struct super_block * sb;
 
        if (dev == ROOT_DEV) {
                printk("VFS: Root device %s: prepare for armageddon\n",
                       kdevname(dev));
                return;
        }
        if (!(sb = get_super(dev)))
                return;
        if (sb->s_covered) {
                printk("VFS: Mounted device %s - tssk, tssk\n",
                       kdevname(dev));
                return;
        }
        if (sb->s_op && sb->s_op->put_super)
                sb->s_op->put_super(sb);
}
 
asmlinkage int sys_ustat(dev_t dev, struct ustat * ubuf)
{
        struct super_block *s;
        struct ustat tmp;
        struct statfs sbuf;
        unsigned long old_fs;
        int error;
 
        s = get_super(to_kdev_t(dev));
        if (s == NULL)
                return -EINVAL;
 
        if (!(s->s_op->statfs))
                return -ENOSYS;
 
        error = verify_area(VERIFY_WRITE,ubuf,sizeof(struct ustat));
        if (error)
                return error;
 
        old_fs = get_fs();
        set_fs(get_ds());
        s->s_op->statfs(s,&sbuf,sizeof(struct statfs));
        set_fs(old_fs);
 
        memset(&tmp,0,sizeof(struct ustat));
        tmp.f_tfree = sbuf.f_bfree;
        tmp.f_tinode = sbuf.f_ffree;
 
        memcpy_tofs(ubuf,&tmp,sizeof(struct ustat));
        return 0;
}
 
static struct super_block * read_super(kdev_t dev,const char *name,int flags,
                                       void *data, int silent)
{
        struct super_block * s;
        struct file_system_type *type;
 
printk("%s - %s:%d\n",__FILE__,__FUNCTION__,__LINE__);
        if (!dev)
                return NULL;
printk("%s - %s:%d\n",__FILE__,__FUNCTION__,__LINE__);
        check_disk_change(dev);
        s = get_super(dev);
printk("%s - %s:%d\n",__FILE__,__FUNCTION__,__LINE__);
        if (s)
                return s;
printk("%s - %s:%d\n",__FILE__,__FUNCTION__,__LINE__);
        if (!(type = get_fs_type(name))) {
                printk("VFS: on device %s: get_fs_type(%s) failed\n",
                       kdevname(dev), name);
                return NULL;
        }
printk("%s - %s:%d\n",__FILE__,__FUNCTION__,__LINE__);
        for (s = 0+super_blocks ;; s++) {
                if (s >= NR_SUPER+super_blocks)
                        return NULL;
                if (!(s->s_dev))
                        break;
        }
printk("%s - %s:%d\n",__FILE__,__FUNCTION__,__LINE__);
        s->s_dev = dev;
        s->s_flags = flags;
        if (!type->read_super(s,data, silent)) {
                s->s_dev = 0;
                return NULL;
        }
printk("%s - %s:%d\n",__FILE__,__FUNCTION__,__LINE__);
        s->s_dev = dev;
        s->s_covered = NULL;
        s->s_rd_only = 0;
        s->s_dirt = 0;
        s->s_type = type;
        return s;
}
 
/*
 * Unnamed block devices are dummy devices used by virtual
 * filesystems which don't use real block-devices.  -- jrs
 */
 
static unsigned int unnamed_dev_in_use[256/(8*sizeof(unsigned int))] = { 0, };
 
kdev_t get_unnamed_dev(void)
{
        int i;
 
        for (i = 1; i < 256; i++) {
                if (!set_bit(i,unnamed_dev_in_use))
                        return MKDEV(UNNAMED_MAJOR, i);
        }
        printk("VFS: Sorry, out of unnamed devices\n");
        return 0;
}
 
void put_unnamed_dev(kdev_t dev)
{
        if (!dev)
                return;
        if (MAJOR(dev) == UNNAMED_MAJOR &&
            clear_bit(MINOR(dev), unnamed_dev_in_use))
                return;
        printk("VFS: put_unnamed_dev: freeing unused device %s\n",
                        kdevname(dev));
}
 
static int do_umount(kdev_t dev,int unmount_root)
{
        struct super_block * sb;
        int retval;
 
        if (dev==ROOT_DEV && !unmount_root) {
                /*
                 * Special case for "unmounting" root. We just try to remount
                 * it readonly, and sync() the device.
                 */
                if (!(sb=get_super(dev)))
                        return -ENOENT;
                if (!(sb->s_flags & MS_RDONLY)) {
                        /*
                         * Make sure all quotas are turned off on this device we need to mount
                         * it readonly so no more writes by the quotasystem.
                         * If later on the remount fails too bad there are no quotas running
                         * anymore. Turn them on again by hand.
                         */
                        quota_off(dev, -1);
                        fsync_dev(dev);
                        retval = do_remount_sb(sb, MS_RDONLY, 0);
                        if (retval)
                                return retval;
                }
                return 0;
        }
        if (!(sb=get_super(dev)) || !(sb->s_covered))
                return -ENOENT;
        if (!sb->s_covered->i_mount)
                printk("VFS: umount(%s): mounted inode has i_mount=NULL\n",
                       kdevname(dev));
        /*
         * Before checking if the filesystem is still busy make sure the kernel
         * doesn't hold any quotafiles open on that device. If the umount fails
         * too bad there are no quotas running anymore. Turn them on again by hand.
         */
        quota_off(dev, -1);
        if (!fs_may_umount(dev, sb->s_mounted))
                return -EBUSY;
        sb->s_covered->i_mount = NULL;
        iput(sb->s_covered);
        sb->s_covered = NULL;
        iput(sb->s_mounted);
        sb->s_mounted = NULL;
        if (sb->s_op && sb->s_op->write_super && sb->s_dirt)
                sb->s_op->write_super(sb);
        put_super(dev);
        remove_vfsmnt(dev);
        return 0;
}
 
/*
 * Now umount can handle mount points as well as block devices.
 * This is important for filesystems which use unnamed block devices.
 *
 * There is a little kludge here with the dummy_inode.  The current
 * vfs release functions only use the r_dev field in the inode so
 * we give them the info they need without using a real inode.
 * If any other fields are ever needed by any block device release
 * functions, they should be faked here.  -- jrs
 */
 
asmlinkage int sys_umount(char * name)
{
        struct inode * inode;
        kdev_t dev;
        int retval;
        struct inode dummy_inode;
 
        if (!suser())
                return -EPERM;
        retval = namei(name, &inode);
        if (retval) {
                retval = lnamei(name, &inode);
                if (retval)
                        return retval;
        }
        if (S_ISBLK(inode->i_mode)) {
                dev = inode->i_rdev;
                if (IS_NODEV(inode)) {
                        iput(inode);
                        return -EACCES;
                }
        } else {
                if (!inode->i_sb || inode != inode->i_sb->s_mounted) {
                        iput(inode);
                        return -EINVAL;
                }
                dev = inode->i_sb->s_dev;
                iput(inode);
                memset(&dummy_inode, 0, sizeof(dummy_inode));
                dummy_inode.i_rdev = dev;
                inode = &dummy_inode;
        }
        if (MAJOR(dev) >= MAX_BLKDEV) {
                iput(inode);
                return -ENXIO;
        }
        retval = do_umount(dev,0);
        if (!retval) {
                fsync_dev(dev);
                if (dev != ROOT_DEV) {
                        blkdev_release (inode);
                        if (MAJOR(dev) == UNNAMED_MAJOR)
                                put_unnamed_dev(dev);
                }
        }
        if (inode != &dummy_inode)
                iput(inode);
        if (retval)
                return retval;
        fsync_dev(dev);
        return 0;
}
 
/*
 * do_mount() does the actual mounting after sys_mount has done the ugly
 * parameter parsing. When enough time has gone by, and everything uses the
 * new mount() parameters, sys_mount() can then be cleaned up.
 *
 * We cannot mount a filesystem if it has active, used, or dirty inodes.
 * We also have to flush all inode-data for this device, as the new mount
 * might need new info.
 */
 
int do_mount(kdev_t dev, const char * dev_name, const char * dir_name, const char * type, int flags, void * data)
{
        struct inode * dir_i;
        struct super_block * sb;
        struct vfsmount *vfsmnt;
        int error;
 
        if (!(flags & MS_RDONLY) && dev && is_read_only(dev))
                return -EACCES;
                /*flags |= MS_RDONLY;*/
        error = namei(dir_name, &dir_i);
        if (error)
                return error;
        if (dir_i->i_count != 1 || dir_i->i_mount) {
                iput(dir_i);
                return -EBUSY;
        }
        if (!S_ISDIR(dir_i->i_mode)) {
                iput(dir_i);
                return -ENOTDIR;
        }
        if (!fs_may_mount(dev)) {
                iput(dir_i);
                return -EBUSY;
        }
        sb = read_super(dev,type,flags,data,0);
        if (!sb) {
                iput(dir_i);
                return -EINVAL;
        }
        if (sb->s_covered) {
                iput(dir_i);
                return -EBUSY;
        }
        vfsmnt = add_vfsmnt(dev, dev_name, dir_name);
        if (vfsmnt) {
                vfsmnt->mnt_sb = sb;
                vfsmnt->mnt_flags = flags;
        }
        sb->s_covered = dir_i;
        dir_i->i_mount = sb->s_mounted;
        return 0;                /* we don't iput(dir_i) - see umount */
}
 
 
/*
 * Alters the mount flags of a mounted file system. Only the mount point
 * is used as a reference - file system type and the device are ignored.
 * FS-specific mount options can't be altered by remounting.
 */
 
static int do_remount_sb(struct super_block *sb, int flags, char *data)
{
        int retval;
        struct vfsmount *vfsmnt;
 
        if (!(flags & MS_RDONLY) && sb->s_dev && is_read_only(sb->s_dev))
                return -EACCES;
                /*flags |= MS_RDONLY;*/
        /* If we are remounting RDONLY, make sure there are no rw files open */
        if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY))
                if (!fs_may_remount_ro(sb->s_dev))
                        return -EBUSY;
        if (sb->s_op && sb->s_op->remount_fs) {
                retval = sb->s_op->remount_fs(sb, &flags, data);
                if (retval)
                        return retval;
        }
        sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
        vfsmnt = lookup_vfsmnt(sb->s_dev);
        if (vfsmnt)
                vfsmnt->mnt_flags = sb->s_flags;
        return 0;
}
 
static int do_remount(const char *dir,int flags,char *data)
{
        struct inode *dir_i;
        int retval;
 
        retval = namei(dir, &dir_i);
        if (retval)
                return retval;
        if (dir_i != dir_i->i_sb->s_mounted) {
                iput(dir_i);
                return -EINVAL;
        }
        retval = do_remount_sb(dir_i->i_sb, flags, data);
        iput(dir_i);
        return retval;
}
 
static int copy_mount_options (const void * data, unsigned long *where)
{
        int i;
        unsigned long page;
#ifndef NO_MM
        struct vm_area_struct * vma;
#endif /* !NO_MM */
 
        *where = 0;
        if (!data)
                return 0;
 
#ifndef NO_MM
        vma = find_vma(current->mm, (unsigned long) data);
        if (!vma || (unsigned long) data < vma->vm_start)
                return -EFAULT;
        if (!(vma->vm_flags & VM_READ))
                return -EFAULT;
        i = vma->vm_end - (unsigned long) data;
        if (PAGE_SIZE <= (unsigned long) i)
                i = PAGE_SIZE-1;
#else /* NO_MM */
        i = PAGE_SIZE-1;
#endif /* NO_MM */
        if (!(page = __get_free_page(GFP_KERNEL))) {
                return -ENOMEM;
        }
        memcpy_fromfs((void *) page,data,i);
        *where = page;
        return 0;
}
 
/*
 * Flags is a 16-bit value that allows up to 16 non-fs dependent flags to
 * be given to the mount() call (ie: read-only, no-dev, no-suid etc).
 *
 * data is a (void *) that can point to any structure up to
 * PAGE_SIZE-1 bytes, which can contain arbitrary fs-dependent
 * information (or be NULL).
 *
 * NOTE! As old versions of mount() didn't use this setup, the flags
 * has to have a special 16-bit magic number in the hight word:
 * 0xC0ED. If this magic word isn't present, the flags and data info
 * isn't used, as the syscall assumes we are talking to an older
 * version that didn't understand them.
 */
asmlinkage int sys_mount(char * dev_name, char * dir_name, char * type,
        unsigned long new_flags, void * data)
{
        struct file_system_type * fstype;
        struct inode * inode;
        struct file_operations * fops;
        kdev_t dev;
        int retval;
        const char * t;
        unsigned long flags = 0;
        unsigned long page = 0;
 
        if (!suser())
                return -EPERM;
        if ((new_flags &
             (MS_MGC_MSK | MS_REMOUNT)) == (MS_MGC_VAL | MS_REMOUNT)) {
                retval = copy_mount_options (data, &page);
                if (retval < 0)
                        return retval;
                retval = do_remount(dir_name,
                                    new_flags & ~MS_MGC_MSK & ~MS_REMOUNT,
                                    (char *) page);
                free_page(page);
                return retval;
        }
        retval = copy_mount_options (type, &page);
        if (retval < 0)
                return retval;
        fstype = get_fs_type((char *) page);
        free_page(page);
        if (!fstype)
                return -ENODEV;
        t = fstype->name;
        fops = NULL;
        if (fstype->requires_dev) {
                retval = namei(dev_name, &inode);
                if (retval)
                        return retval;
                if (!S_ISBLK(inode->i_mode)) {
                        iput(inode);
                        return -ENOTBLK;
                }
                if (IS_NODEV(inode)) {
                        iput(inode);
                        return -EACCES;
                }
                dev = inode->i_rdev;
                if (MAJOR(dev) >= MAX_BLKDEV) {
                        iput(inode);
                        return -ENXIO;
                }
                fops = get_blkfops(MAJOR(dev));
                if (!fops) {
                        iput(inode);
                        return -ENOTBLK;
                }
                if (fops->open) {
                        struct file dummy;      /* allows read-write or read-only flag */
                        memset(&dummy, 0, sizeof(dummy));
                        dummy.f_inode = inode;
                        dummy.f_mode = (new_flags & MS_RDONLY) ? 1 : 3;
                        retval = fops->open(inode, &dummy);
                        if (retval) {
                                iput(inode);
                                return retval;
                        }
                }
 
        } else {
                if (!(dev = get_unnamed_dev()))
                        return -EMFILE;
                inode = NULL;
        }
        page = 0;
        if ((new_flags & MS_MGC_MSK) == MS_MGC_VAL) {
                flags = new_flags & ~MS_MGC_MSK;
                retval = copy_mount_options(data, &page);
                if (retval < 0) {
                        iput(inode);
                        return retval;
                }
        }
        retval = do_mount(dev,dev_name,dir_name,t,flags,(void *) page);
        free_page(page);
        if (retval && !fstype->requires_dev)
                put_unnamed_dev(dev);
        if (retval && fops && fops->release)
                fops->release(inode, NULL);
        iput(inode);
        return retval;
}
 
static void do_mount_root(void)
{
        struct file_system_type * fs_type;
        struct super_block * sb;
        struct vfsmount *vfsmnt;
        struct inode * inode, d_inode;
        struct file filp;
        int retval;
printk("do_mount_root1\n");
#ifdef CONFIG_ROOT_NFS
        if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR)
                if (nfs_root_init(nfs_root_name, nfs_root_addrs) < 0) {
                        printk(KERN_ERR "Root-NFS: Unable to contact NFS "
                            "server for root fs, using /dev/fd0 instead\n");
                        ROOT_DEV = MKDEV(FLOPPY_MAJOR, 0);
                }
        if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR) {
                ROOT_DEV = 0;
                if ((fs_type = get_fs_type("nfs"))) {
                        sb = &super_blocks[0];
                        while (sb->s_dev) sb++;
                        sb->s_dev = get_unnamed_dev();
                        sb->s_flags = root_mountflags & ~MS_RDONLY;
                        if (nfs_root_mount(sb) >= 0) {
                                inode = sb->s_mounted;
                                inode->i_count += 3 ;
                                sb->s_covered = inode;
                                sb->s_rd_only = 0;
                                sb->s_dirt = 0;
                                sb->s_type = fs_type;
                                current->fs->pwd = inode;
                                current->fs->root = inode;
                                ROOT_DEV = sb->s_dev;
                                printk (KERN_NOTICE "VFS: Mounted root (nfs filesystem).\n");
                                vfsmnt = add_vfsmnt(ROOT_DEV, "/dev/root", "/");
                                if (!vfsmnt)
                                        panic("VFS: add_vfsmnt failed for NFS root.\n");
                                vfsmnt->mnt_sb = sb;
                                vfsmnt->mnt_flags = sb->s_flags;
                                return;
                        }
                        sb->s_dev = 0;
                }
                if (!ROOT_DEV) {
                        printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
                        ROOT_DEV = MKDEV(FLOPPY_MAJOR, 0);
                }
        }
#endif
 
#ifdef CONFIG_BLK_DEV_FD
        if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
#ifdef CONFIG_BLK_DEV_INITRD
                extern int rd_doload;
#endif
                floppy_eject();
#ifndef CONFIG_BLK_DEV_RAM
                printk(KERN_NOTICE "(Warning, this kernel has no ramdisk support)\n");
#endif
#ifdef CONFIG_BLK_DEV_INITRD
                /* rd_doload is 2 for a dual initrd/ramload setup */
                if(rd_doload==2)
                        rd_load_secondary();
                else
#endif          
                {
                        printk(KERN_NOTICE "VFS: Insert root floppy and press ENTER\n");
                        wait_for_keypress();
                }
        }
#endif
 
        memset(&filp, 0, sizeof(filp));
        memset(&d_inode, 0, sizeof(d_inode));
        d_inode.i_rdev = ROOT_DEV;
        filp.f_inode = &d_inode;
        if ( root_mountflags & MS_RDONLY)
                filp.f_mode = 1; /* read only */
        else
                filp.f_mode = 3; /* read write */
printk("do_mount_root2\n");
        retval = blkdev_open(&d_inode, &filp);
        if (retval == -EROFS) {
                root_mountflags |= MS_RDONLY;
                filp.f_mode = 1;
                retval = blkdev_open(&d_inode, &filp);
        }
printk("do_mount_root3\n");
        if (retval)
                /*
                 * Allow the user to distinguish between failed open
                 * and bad superblock on root device.
                 */
                printk("VFS: Cannot open root device %s\n",
                       kdevname(ROOT_DEV));
        else for (fs_type = file_systems ; fs_type ; fs_type = fs_type->next) {
printk("do_mount_root4\n");
                if (!fs_type->requires_dev)
                        continue;
printk("do_mount_root5\n");
                sb = read_super(ROOT_DEV,fs_type->name,root_mountflags,NULL,0);
                if (sb) {
printk("do_mount_root6\n");
                        inode = sb->s_mounted;
                        inode->i_count += 3 ;   /* NOTE! it is logically used 4 times, not 1 */
                        sb->s_covered = inode;
                        sb->s_flags = root_mountflags;
                        current->fs->pwd = inode;
                        current->fs->root = inode;
                        printk ("VFS: Mounted root (%s filesystem)%s.\n",
                                fs_type->name,
                                (sb->s_flags & MS_RDONLY) ? " readonly" : "");
                        vfsmnt = add_vfsmnt(ROOT_DEV, "/dev/root", "/");
                        if (!vfsmnt)
                                panic("VFS: add_vfsmnt failed for root fs");
                        vfsmnt->mnt_sb = sb;
                        vfsmnt->mnt_flags = root_mountflags;
                        return;
                }
        }
        panic("VFS: Unable to mount root fs on %s",
                kdevname(ROOT_DEV));
}
 
 
void mount_root(void)
{
        memset(super_blocks, 0, sizeof(super_blocks));
        do_mount_root();
}
 
 
#ifdef CONFIG_BLK_DEV_INITRD
 
int change_root(kdev_t new_root_dev,const char *put_old)
{
        kdev_t old_root_dev;
        struct vfsmount *vfsmnt;
        struct inode *old_root,*old_pwd,*inode;
        unsigned long old_fs;
        int error;
 
        old_root = current->fs->root;
        old_pwd = current->fs->pwd;
        old_root_dev = ROOT_DEV;
        if (!fs_may_mount(new_root_dev)) {
                printk(KERN_CRIT "New root is busy. Staying in initrd.\n");
                return -EBUSY;
        }
        ROOT_DEV = new_root_dev;
        do_mount_root();
        old_fs = get_fs();
        set_fs(get_ds());
        error = namei(put_old,&inode);
        if (error) inode = NULL;
        set_fs(old_fs);
        if (!error && (inode->i_count != 1 || inode->i_mount)) error = -EBUSY;
        if (!error && !S_ISDIR(inode->i_mode)) error = -ENOTDIR;
        iput(old_root); /* current->fs->root */
        iput(old_pwd); /* current->fs->pwd */
        if (error) {
                int umount_error;
 
                if (inode) iput(inode);
                printk(KERN_NOTICE "Trying to unmount old root ... ");
                old_root->i_mount = old_root;
                        /* does this belong into do_mount_root ? */
                umount_error = do_umount(old_root_dev,1);
                if (umount_error) printk(KERN_ERR "error %d\n",umount_error);
                else {
                        printk("okay\n");
                        invalidate_buffers(old_root_dev);
                }
                return umount_error ? error : 0;
        }
        iput(old_root); /* sb->s_covered */
        remove_vfsmnt(old_root_dev);
        vfsmnt = add_vfsmnt(old_root_dev,"/dev/root.old",put_old);
        if (!vfsmnt) printk(KERN_CRIT "Trouble: add_vfsmnt failed\n");
        else {
                vfsmnt->mnt_sb = old_root->i_sb;
                vfsmnt->mnt_sb->s_covered = inode;
                vfsmnt->mnt_flags = vfsmnt->mnt_sb->s_flags;
        }
        inode->i_mount = old_root;
        return 0;
}
 
#endif
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[/] [or1k/] [trunk/] [uclinux/] [uClinux-2.0.x/] [fs/] [super.c] - Blame information for rev 199

Line No.	Rev	Author	Line
1	199	simons	`/*`
2			`* linux/fs/super.c`
3			`*`
4			`* Copyright (C) 1991, 1992 Linus Torvalds`
5			`*`
6			`* super.c contains code to handle: - mount structures`
7			`* - super-block tables.`
8			`* - mount systemcall`
9			`* - umount systemcall`
10			`*`
11			`* Added options to /proc/mounts`
12			`* Torbj�rn Lindh (torbjorn.lindh@gopta.se), April 14, 1996.`
13			`*`
14			`* GK 2/5/95 - Changed to support mounting the root fs via NFS`
15			`*`
16			`* Added kerneld support: Jacques Gelinas and Bjorn Ekwall`
17			`* Added change_root: Werner Almesberger & Hans Lermen, Feb '96`
18			`*/`
19
20			`/*`
21			`* uClinux revisions for NO_MM`
22			`* Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com>,`
23			`* The Silver Hammer Group, Ltd.`
24			`*/`
25
26			`#include <stdarg.h>`
27
28			`#include <linux/config.h>`
29			`#include <linux/sched.h>`
30			`#include <linux/kernel.h>`
31			`#include <linux/mount.h>`
32			`#include <linux/malloc.h>`
33			`#include <linux/major.h>`
34			`#include <linux/stat.h>`
35			`#include <linux/errno.h>`
36			`#include <linux/string.h>`
37			`#include <linux/locks.h>`
38			`#include <linux/mm.h>`
39			`#include <linux/fd.h>`
40