[MTD] generalise the handling of MTD-specific superblocks
Generalise the handling of MTD-specific superblocks so that JFFS2 and ROMFS can both share it. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
This commit is contained in:
David Howells
committed by
David Woodhouse
David Woodhouse
parent
33672f72b2
commit
acaebfd8a7
232
drivers/mtd/mtdsuper.c
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232
drivers/mtd/mtdsuper.c
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/* MTD-based superblock management
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*
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* Copyright © 2001-2007 Red Hat, Inc. All Rights Reserved.
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* Written by: David Howells <dhowells@redhat.com>
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* David Woodhouse <dwmw2@infradead.org>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/mtd/super.h>
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#include <linux/namei.h>
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#include <linux/ctype.h>
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/*
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* compare superblocks to see if they're equivalent
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* - they are if the underlying MTD device is the same
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*/
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static int get_sb_mtd_compare(struct super_block *sb, void *_mtd)
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{
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struct mtd_info *mtd = _mtd;
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if (sb->s_mtd == mtd) {
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DEBUG(2, "MTDSB: Match on device %d (\"%s\")\n",
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mtd->index, mtd->name);
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return 1;
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}
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DEBUG(2, "MTDSB: No match, device %d (\"%s\"), device %d (\"%s\")\n",
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sb->s_mtd->index, sb->s_mtd->name, mtd->index, mtd->name);
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return 0;
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}
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/*
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* mark the superblock by the MTD device it is using
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* - set the device number to be the correct MTD block device for pesuperstence
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* of NFS exports
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*/
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static int get_sb_mtd_set(struct super_block *sb, void *_mtd)
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{
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struct mtd_info *mtd = _mtd;
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sb->s_mtd = mtd;
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sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
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return 0;
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}
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/*
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* get a superblock on an MTD-backed filesystem
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*/
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static int get_sb_mtd_aux(struct file_system_type *fs_type, int flags,
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const char *dev_name, void *data,
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struct mtd_info *mtd,
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int (*fill_super)(struct super_block *, void *, int),
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struct vfsmount *mnt)
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{
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struct super_block *sb;
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int ret;
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sb = sget(fs_type, get_sb_mtd_compare, get_sb_mtd_set, mtd);
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if (IS_ERR(sb))
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goto out_error;
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if (sb->s_root)
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goto already_mounted;
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/* fresh new superblock */
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DEBUG(1, "MTDSB: New superblock for device %d (\"%s\")\n",
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mtd->index, mtd->name);
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ret = fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
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if (ret < 0) {
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up_write(&sb->s_umount);
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deactivate_super(sb);
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return ret;
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}
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/* go */
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sb->s_flags |= MS_ACTIVE;
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return simple_set_mnt(mnt, sb);
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/* new mountpoint for an already mounted superblock */
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already_mounted:
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DEBUG(1, "MTDSB: Device %d (\"%s\") is already mounted\n",
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mtd->index, mtd->name);
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ret = simple_set_mnt(mnt, sb);
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goto out_put;
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out_error:
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ret = PTR_ERR(sb);
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out_put:
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put_mtd_device(mtd);
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return ret;
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}
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/*
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* get a superblock on an MTD-backed filesystem by MTD device number
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*/
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static int get_sb_mtd_nr(struct file_system_type *fs_type, int flags,
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const char *dev_name, void *data, int mtdnr,
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int (*fill_super)(struct super_block *, void *, int),
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struct vfsmount *mnt)
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{
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struct mtd_info *mtd;
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mtd = get_mtd_device(NULL, mtdnr);
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if (!mtd) {
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DEBUG(0, "MTDSB: Device #%u doesn't appear to exist\n", mtdnr);
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return -EINVAL;
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}
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return get_sb_mtd_aux(fs_type, flags, dev_name, data, mtd, fill_super,
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mnt);
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}
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/*
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* set up an MTD-based superblock
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*/
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int get_sb_mtd(struct file_system_type *fs_type, int flags,
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const char *dev_name, void *data,
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int (*fill_super)(struct super_block *, void *, int),
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struct vfsmount *mnt)
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{
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struct nameidata nd;
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int mtdnr, ret;
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if (!dev_name)
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return -EINVAL;
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DEBUG(2, "MTDSB: dev_name \"%s\"\n", dev_name);
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/* the preferred way of mounting in future; especially when
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* CONFIG_BLOCK=n - we specify the underlying MTD device by number or
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* by name, so that we don't require block device support to be present
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* in the kernel. */
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if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
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if (dev_name[3] == ':') {
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struct mtd_info *mtd;
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/* mount by MTD device name */
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DEBUG(1, "MTDSB: mtd:%%s, name \"%s\"\n",
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dev_name + 4);
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for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) {
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mtd = get_mtd_device(NULL, mtdnr);
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if (mtd) {
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if (!strcmp(mtd->name, dev_name + 4))
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return get_sb_mtd_aux(
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fs_type, flags,
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dev_name, data, mtd,
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fill_super, mnt);
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put_mtd_device(mtd);
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}
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}
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printk(KERN_NOTICE "MTD:"
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" MTD device with name \"%s\" not found.\n",
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dev_name + 4);
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} else if (isdigit(dev_name[3])) {
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/* mount by MTD device number name */
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char *endptr;
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mtdnr = simple_strtoul(dev_name + 3, &endptr, 0);
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if (!*endptr) {
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/* It was a valid number */
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DEBUG(1, "MTDSB: mtd%%d, mtdnr %d\n",
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mtdnr);
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return get_sb_mtd_nr(fs_type, flags,
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dev_name, data,
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mtdnr, fill_super, mnt);
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}
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}
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}
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/* try the old way - the hack where we allowed users to mount
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* /dev/mtdblock$(n) but didn't actually _use_ the blockdev
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*/
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ret = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
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DEBUG(1, "MTDSB: path_lookup() returned %d, inode %p\n",
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ret, nd.dentry ? nd.dentry->d_inode : NULL);
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if (ret)
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return ret;
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ret = -EINVAL;
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if (!S_ISBLK(nd.dentry->d_inode->i_mode))
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goto out;
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if (nd.mnt->mnt_flags & MNT_NODEV) {
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ret = -EACCES;
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goto out;
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}
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if (imajor(nd.dentry->d_inode) != MTD_BLOCK_MAJOR)
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goto not_an_MTD_device;
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mtdnr = iminor(nd.dentry->d_inode);
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path_release(&nd);
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return get_sb_mtd_nr(fs_type, flags, dev_name, data, mtdnr, fill_super,
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mnt);
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not_an_MTD_device:
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if (!(flags & MS_SILENT))
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printk(KERN_NOTICE
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"MTD: Attempt to mount non-MTD device \"%s\"\n",
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dev_name);
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out:
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path_release(&nd);
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return ret;
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}
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EXPORT_SYMBOL_GPL(get_sb_mtd);
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/*
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* destroy an MTD-based superblock
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*/
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void kill_mtd_super(struct super_block *sb)
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{
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generic_shutdown_super(sb);
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put_mtd_device(sb->s_mtd);
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sb->s_mtd = NULL;
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}
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EXPORT_SYMBOL_GPL(kill_mtd_super);
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