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

[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

drivers/mtd/Makefile

+1 −2
Original line number Diff line number Diff line 
#

# 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)

drivers/mtd/mtdsuper.c

0 → 100644
+232 −0
Original line number Diff line number Diff line 
/* 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);

fs/jffs2/super.c

+19 −175
Original line number Diff line number Diff line
@@ -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;

	c->mtd = sb->s_mtd;

	c->os_priv = sb;

	sb->s_fs_info = c;



	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));



	/* 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);

}

include/linux/fs.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */

include/linux/mtd/super.h

0 → 100644
+30 −0
Original line number Diff line number Diff line 
/* 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__ */

CRA Git | Maintained and supported by SUSTech CRA and CCSE