Commit acaebfd8 authored by David Howells's avatar David Howells Committed by David Woodhouse

[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: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent 33672f72
#
# Makefile for the memory technology device drivers.
#
# $Id: Makefile.common,v 1.7 2005/07/11 10:39:27 gleixner Exp $
# Core functionality.
mtd-y := mtdcore.o
mtd-y := mtdcore.o mtdsuper.o
mtd-$(CONFIG_MTD_PARTITIONS) += mtdpart.o
obj-$(CONFIG_MTD) += $(mtd-y)
......
/* 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 (!mtd) {
DEBUG(0, "MTDSB: Device #%u doesn't appear to exist\n", mtdnr);
return -EINVAL;
}
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 (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);
......@@ -19,7 +19,7 @@
#include <linux/mount.h>
#include <linux/jffs2.h>
#include <linux/pagemap.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/super.h>
#include <linux/ctype.h>
#include <linux/namei.h>
#include "compr.h"
......@@ -78,69 +78,27 @@ static const struct super_operations jffs2_super_operations =
.sync_fs = jffs2_sync_fs,
};
static int jffs2_sb_compare(struct super_block *sb, void *data)
{
struct jffs2_sb_info *p = data;
struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
/* The superblocks are considered to be equivalent if the underlying MTD
device is the same one */
if (c->mtd == p->mtd) {
D1(printk(KERN_DEBUG "jffs2_sb_compare: match on device %d (\"%s\")\n", p->mtd->index, p->mtd->name));
return 1;
} else {
D1(printk(KERN_DEBUG "jffs2_sb_compare: No match, device %d (\"%s\"), device %d (\"%s\")\n",
c->mtd->index, c->mtd->name, p->mtd->index, p->mtd->name));
return 0;
}
}
static int jffs2_sb_set(struct super_block *sb, void *data)
{
struct jffs2_sb_info *p = data;
/* For persistence of NFS exports etc. we use the same s_dev
each time we mount the device, don't just use an anonymous
device */
sb->s_fs_info = p;
p->os_priv = sb;
sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, p->mtd->index);
return 0;
}
static int jffs2_get_sb_mtd(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *data, struct mtd_info *mtd,
struct vfsmount *mnt)
/*
* fill in the superblock
*/
static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
{
struct super_block *sb;
struct jffs2_sb_info *c;
int ret;
D1(printk(KERN_DEBUG "jffs2_get_sb_mtd():"
" New superblock for device %d (\"%s\")\n",
sb->s_mtd->index, sb->s_mtd->name));
c = kzalloc(sizeof(*c), GFP_KERNEL);
if (!c)
return -ENOMEM;
c->mtd = mtd;
sb = sget(fs_type, jffs2_sb_compare, jffs2_sb_set, c);
if (IS_ERR(sb))
goto out_error;
if (sb->s_root) {
/* New mountpoint for JFFS2 which is already mounted */
D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): Device %d (\"%s\") is already mounted\n",
mtd->index, mtd->name));
ret = simple_set_mnt(mnt, sb);
goto out_put;
}
D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): New superblock for device %d (\"%s\")\n",
mtd->index, mtd->name));
c->mtd = sb->s_mtd;
c->os_priv = sb;
sb->s_fs_info = c;
/* Initialize JFFS2 superblock locks, the further initialization will be
* done later */
/* Initialize JFFS2 superblock locks, the further initialization will
* be done later */
init_MUTEX(&c->alloc_sem);
init_MUTEX(&c->erase_free_sem);
init_waitqueue_head(&c->erase_wait);
......@@ -149,133 +107,20 @@ static int jffs2_get_sb_mtd(struct file_system_type *fs_type,
spin_lock_init(&c->inocache_lock);
sb->s_op = &jffs2_super_operations;
sb->s_flags = flags | MS_NOATIME;
sb->s_flags = sb->s_flags | MS_NOATIME;
sb->s_xattr = jffs2_xattr_handlers;
#ifdef CONFIG_JFFS2_FS_POSIX_ACL
sb->s_flags |= MS_POSIXACL;
#endif
ret = jffs2_do_fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
if (ret) {
/* Failure case... */
up_write(&sb->s_umount);
deactivate_super(sb);
return ret;
}
sb->s_flags |= MS_ACTIVE;
return simple_set_mnt(mnt, sb);
out_error:
ret = PTR_ERR(sb);
out_put:
kfree(c);
put_mtd_device(mtd);
return ret;
}
static int jffs2_get_sb_mtdnr(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *data, int mtdnr,
struct vfsmount *mnt)
{
struct mtd_info *mtd;
mtd = get_mtd_device(NULL, mtdnr);
if (IS_ERR(mtd)) {
D1(printk(KERN_DEBUG "jffs2: MTD device #%u doesn't appear to exist\n", mtdnr));
return PTR_ERR(mtd);
}
return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd, mnt);
return jffs2_do_fill_super(sb, data, silent);
}
static int jffs2_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *data, struct vfsmount *mnt)
{
int err;
struct nameidata nd;
int mtdnr;
if (!dev_name)
return -EINVAL;
D1(printk(KERN_DEBUG "jffs2_get_sb(): dev_name \"%s\"\n", dev_name));
/* The preferred way of mounting in future; especially when
CONFIG_BLK_DEV is implemented - 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. */
/* FIXME: How to do the root fs this way? */
if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
/* Probably mounting without the blkdev crap */
if (dev_name[3] == ':') {
struct mtd_info *mtd;
/* Mount by MTD device name */
D1(printk(KERN_DEBUG "jffs2_get_sb(): 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 jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd, mnt);
put_mtd_device(mtd);
}
}
printk(KERN_NOTICE "jffs2_get_sb(): 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 */
D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd%%d, mtdnr %d\n", mtdnr));
return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr, mnt);
}
}
}
/* Try the old way - the hack where we allowed users to mount
/dev/mtdblock$(n) but didn't actually _use_ the blkdev */
err = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
D1(printk(KERN_DEBUG "jffs2_get_sb(): path_lookup() returned %d, inode %p\n",
err, nd.dentry->d_inode));
if (err)
return err;
err = -EINVAL;
if (!S_ISBLK(nd.dentry->d_inode->i_mode))
goto out;
if (nd.mnt->mnt_flags & MNT_NODEV) {
err = -EACCES;
goto out;
}
if (imajor(nd.dentry->d_inode) != MTD_BLOCK_MAJOR) {
if (!(flags & MS_SILENT))
printk(KERN_NOTICE "Attempt to mount non-MTD device \"%s\" as JFFS2\n",
dev_name);
goto out;
}
mtdnr = iminor(nd.dentry->d_inode);
path_release(&nd);
return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr, mnt);
out:
path_release(&nd);
return err;
return get_sb_mtd(fs_type, flags, dev_name, data, jffs2_fill_super,
mnt);
}
static void jffs2_put_super (struct super_block *sb)
......@@ -310,8 +155,7 @@ static void jffs2_kill_sb(struct super_block *sb)
struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
if (!(sb->s_flags & MS_RDONLY))
jffs2_stop_garbage_collect_thread(c);
generic_shutdown_super(sb);
put_mtd_device(c->mtd);
kill_mtd_super(sb);
kfree(c);
}
......
......@@ -937,6 +937,7 @@ struct super_block {
struct list_head s_files;
struct block_device *s_bdev;
struct mtd_info *s_mtd;
struct list_head s_instances;
struct quota_info s_dquot; /* Diskquota specific options */
......
/* MTD-based superblock handling
*
* Copyright © 2006 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* 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.
*/
#ifndef __MTD_SUPER_H__
#define __MTD_SUPER_H__
#ifdef __KERNEL__
#include <linux/mtd/mtd.h>
#include <linux/fs.h>
#include <linux/mount.h>
extern 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);
extern void kill_mtd_super(struct super_block *sb);
#endif /* __KERNEL__ */
#endif /* __MTD_SUPER_H__ */
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