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/* MTD-based superblock management
*
* Copyright © 2001-2007 Red Hat, Inc. All Rights Reserved.
* Written by: David Howells <dhowells@redhat.com>
* David Woodhouse <dwmw2@infradead.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/mtd/super.h>
#include <linux/namei.h>
#include <linux/ctype.h>
/*
* compare superblocks to see if they're equivalent
* - they are if the underlying MTD device is the same
*/
static int get_sb_mtd_compare(struct super_block *sb, void *_mtd)
{
struct mtd_info *mtd = _mtd;
if (sb->s_mtd == mtd) {
DEBUG(2, "MTDSB: Match on device %d (\"%s\")\n",
mtd->index, mtd->name);
return 1;
}
DEBUG(2, "MTDSB: No match, device %d (\"%s\"), device %d (\"%s\")\n",
sb->s_mtd->index, sb->s_mtd->name, mtd->index, mtd->name);
return 0;
}
/*
* mark the superblock by the MTD device it is using
* - set the device number to be the correct MTD block device for pesuperstence
* of NFS exports
*/
static int get_sb_mtd_set(struct super_block *sb, void *_mtd)
{
struct mtd_info *mtd = _mtd;
sb->s_mtd = mtd;
sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
return 0;
}
/*
* get a superblock on an MTD-backed filesystem
*/
static int get_sb_mtd_aux(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data,
struct mtd_info *mtd,
int (*fill_super)(struct super_block *, void *, int),
struct vfsmount *mnt)
{
struct super_block *sb;
int ret;
sb = sget(fs_type, get_sb_mtd_compare, get_sb_mtd_set, mtd);
if (IS_ERR(sb))
goto out_error;
if (sb->s_root)
goto already_mounted;
/* fresh new superblock */
DEBUG(1, "MTDSB: New superblock for device %d (\"%s\")\n",
mtd->index, mtd->name);
ret = fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
if (ret < 0) {
up_write(&sb->s_umount);
deactivate_super(sb);
return ret;
}
/* go */
sb->s_flags |= MS_ACTIVE;
return simple_set_mnt(mnt, sb);
/* new mountpoint for an already mounted superblock */
already_mounted:
DEBUG(1, "MTDSB: Device %d (\"%s\") is already mounted\n",
mtd->index, mtd->name);
ret = simple_set_mnt(mnt, sb);
goto out_put;
out_error:
ret = PTR_ERR(sb);
out_put:
put_mtd_device(mtd);
return ret;
}
/*
* get a superblock on an MTD-backed filesystem by MTD device number
*/
static int get_sb_mtd_nr(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data, int mtdnr,
int (*fill_super)(struct super_block *, void *, int),
struct vfsmount *mnt)
{
struct mtd_info *mtd;
mtd = get_mtd_device(NULL, mtdnr);
if (IS_ERR(mtd)) {
DEBUG(0, "MTDSB: Device #%u doesn't appear to exist\n", mtdnr);
return PTR_ERR(mtd);
}
return get_sb_mtd_aux(fs_type, flags, dev_name, data, mtd, fill_super,
mnt);
}
/*
* set up an MTD-based superblock
*/
int get_sb_mtd(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data,
int (*fill_super)(struct super_block *, void *, int),
struct vfsmount *mnt)
{
struct nameidata nd;
int mtdnr, ret;
if (!dev_name)
return -EINVAL;
DEBUG(2, "MTDSB: dev_name \"%s\"\n", dev_name);
/* the preferred way of mounting in future; especially when
* CONFIG_BLOCK=n - we specify the underlying MTD device by number or
* by name, so that we don't require block device support to be present
* in the kernel. */
if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
if (dev_name[3] == ':') {
struct mtd_info *mtd;
/* mount by MTD device name */
DEBUG(1, "MTDSB: mtd:%%s, name \"%s\"\n",
dev_name + 4);
for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) {
mtd = get_mtd_device(NULL, mtdnr);
if (!IS_ERR(mtd)) {
if (!strcmp(mtd->name, dev_name + 4))
return get_sb_mtd_aux(
fs_type, flags,
dev_name, data, mtd,
fill_super, mnt);
put_mtd_device(mtd);
}
}
printk(KERN_NOTICE "MTD:"
" MTD device with name \"%s\" not found.\n",
dev_name + 4);
} else if (isdigit(dev_name[3])) {
/* mount by MTD device number name */
char *endptr;
mtdnr = simple_strtoul(dev_name + 3, &endptr, 0);
if (!*endptr) {
/* It was a valid number */
DEBUG(1, "MTDSB: mtd%%d, mtdnr %d\n",
mtdnr);
return get_sb_mtd_nr(fs_type, flags,
dev_name, data,
mtdnr, fill_super, mnt);
}
}
}
/* try the old way - the hack where we allowed users to mount
* /dev/mtdblock$(n) but didn't actually _use_ the blockdev
*/
ret = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
DEBUG(1, "MTDSB: path_lookup() returned %d, inode %p\n",
ret, nd.dentry ? nd.dentry->d_inode : NULL);
if (ret)
return ret;
ret = -EINVAL;
if (!S_ISBLK(nd.dentry->d_inode->i_mode))
goto out;
if (nd.mnt->mnt_flags & MNT_NODEV) {
ret = -EACCES;
goto out;
}
if (imajor(nd.dentry->d_inode) != MTD_BLOCK_MAJOR)
goto not_an_MTD_device;
mtdnr = iminor(nd.dentry->d_inode);
path_release(&nd);
return get_sb_mtd_nr(fs_type, flags, dev_name, data, mtdnr, fill_super,
mnt);
not_an_MTD_device:
if (!(flags & MS_SILENT))
printk(KERN_NOTICE
"MTD: Attempt to mount non-MTD device \"%s\"\n",
dev_name);
out:
path_release(&nd);
return ret;
}
EXPORT_SYMBOL_GPL(get_sb_mtd);
/*
* destroy an MTD-based superblock
*/
void kill_mtd_super(struct super_block *sb)
{
generic_shutdown_super(sb);
put_mtd_device(sb->s_mtd);
sb->s_mtd = NULL;
}
EXPORT_SYMBOL_GPL(kill_mtd_super);
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