fs/jffs2/super.c - linux - Git at Google

 /*
  * JFFS2 -- Journalling Flash File System, Version 2.
  *
  * Copyright © 2001-2007 Red Hat, Inc.
  *
  * Created by David Woodhouse <dwmw2@infradead.org>
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/list.h>
 #include <linux/fs.h>
 #include <linux/err.h>
 #include <linux/mount.h>
 #include <linux/fs_context.h>
 #include <linux/fs_parser.h>
 #include <linux/jffs2.h>
 #include <linux/pagemap.h>
 #include <linux/mtd/super.h>
 #include <linux/ctype.h>
 #include <linux/namei.h>
 #include <linux/seq_file.h>
 #include <linux/exportfs.h>
 #include "compr.h"
 #include "nodelist.h"

 static void jffs2_put_super(struct super_block *);

 static struct kmem_cache *jffs2_inode_cachep;

 static struct inode *jffs2_alloc_inode(struct super_block *sb)
 {
 	struct jffs2_inode_info *f;

 	f = alloc_inode_sb(sb, jffs2_inode_cachep, GFP_KERNEL);
 	if (!f)
 		return NULL;
 	return &f->vfs_inode;
 }

 static void jffs2_free_inode(struct inode *inode)
 {
 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);

 	kfree(f->target);
 	kmem_cache_free(jffs2_inode_cachep, f);
 }

 static void jffs2_i_init_once(void *foo)
 {
 	struct jffs2_inode_info *f = foo;

 	mutex_init(&f->sem);
 	f->target = NULL;
 	inode_init_once(&f->vfs_inode);
 }

 static const char *jffs2_compr_name(unsigned int compr)
 {
 	switch (compr) {
 	case JFFS2_COMPR_MODE_NONE:
 		return "none";
 #ifdef CONFIG_JFFS2_LZO
 	case JFFS2_COMPR_MODE_FORCELZO:
 		return "lzo";
 #endif
 #ifdef CONFIG_JFFS2_ZLIB
 	case JFFS2_COMPR_MODE_FORCEZLIB:
 		return "zlib";
 #endif
 	default:
 		/* should never happen; programmer error */
 		WARN_ON(1);
 		return "";
 	}
 }

 static int jffs2_show_options(struct seq_file *s, struct dentry *root)
 {
 	struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
 	struct jffs2_mount_opts *opts = &c->mount_opts;

 	if (opts->override_compr)
 		seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
 	if (opts->set_rp_size)
 		seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);

 	return 0;
 }

 static int jffs2_sync_fs(struct super_block *sb, int wait)
 {
 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);

 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 	if (jffs2_is_writebuffered(c))
 		cancel_delayed_work_sync(&c->wbuf_dwork);
 #endif

 	mutex_lock(&c->alloc_sem);
 	jffs2_flush_wbuf_pad(c);
 	mutex_unlock(&c->alloc_sem);
 	return 0;
 }

 static struct inode *jffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
 					 uint32_t generation)
 {
 	/* We don't care about i_generation. We'll destroy the flash
 	   before we start re-using inode numbers anyway. And even
 	   if that wasn't true, we'd have other problems...*/
 	return jffs2_iget(sb, ino);
 }

 static struct dentry *jffs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 					 int fh_len, int fh_type)
 {
         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
                                     jffs2_nfs_get_inode);
 }

 static struct dentry *jffs2_fh_to_parent(struct super_block *sb, struct fid *fid,
 					 int fh_len, int fh_type)
 {
         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
                                     jffs2_nfs_get_inode);
 }

 static struct dentry *jffs2_get_parent(struct dentry *child)
 {
 	struct jffs2_inode_info *f;
 	uint32_t pino;

 	BUG_ON(!d_is_dir(child));

 	f = JFFS2_INODE_INFO(d_inode(child));

 	pino = f->inocache->pino_nlink;

 	JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
 		    f->inocache->ino, pino);

 	return d_obtain_alias(jffs2_iget(child->d_sb, pino));
 }

 static const struct export_operations jffs2_export_ops = {
 	.encode_fh = generic_encode_ino32_fh,
 	.get_parent = jffs2_get_parent,
 	.fh_to_dentry = jffs2_fh_to_dentry,
 	.fh_to_parent = jffs2_fh_to_parent,
 };

 /*
  * JFFS2 mount options.
  *
  * Opt_source: The source device
  * Opt_override_compr: override default compressor
  * Opt_rp_size: size of reserved pool in KiB
  */
 enum {
 	Opt_override_compr,
 	Opt_rp_size,
 };

 static const struct constant_table jffs2_param_compr[] = {
 	{"none",	JFFS2_COMPR_MODE_NONE },
 #ifdef CONFIG_JFFS2_LZO
 	{"lzo",		JFFS2_COMPR_MODE_FORCELZO },
 #endif
 #ifdef CONFIG_JFFS2_ZLIB
 	{"zlib",	JFFS2_COMPR_MODE_FORCEZLIB },
 #endif
 	{}
 };

 static const struct fs_parameter_spec jffs2_fs_parameters[] = {
 	fsparam_enum	("compr",	Opt_override_compr, jffs2_param_compr),
 	fsparam_u32	("rp_size",	Opt_rp_size),
 	{}
 };

 static int jffs2_parse_param(struct fs_context *fc, struct fs_parameter *param)
 {
 	struct fs_parse_result result;
 	struct jffs2_sb_info *c = fc->s_fs_info;
 	int opt;

 	opt = fs_parse(fc, jffs2_fs_parameters, param, &result);
 	if (opt < 0)
 		return opt;

 	switch (opt) {
 	case Opt_override_compr:
 		c->mount_opts.compr = result.uint_32;
 		c->mount_opts.override_compr = true;
 		break;
 	case Opt_rp_size:
 		if (result.uint_32 > UINT_MAX / 1024)
 			return invalf(fc, "jffs2: rp_size unrepresentable");
 		c->mount_opts.rp_size = result.uint_32 * 1024;
 		c->mount_opts.set_rp_size = true;
 		break;
 	default:
 		return -EINVAL;
 	}

 	return 0;
 }

 static inline void jffs2_update_mount_opts(struct fs_context *fc)
 {
 	struct jffs2_sb_info *new_c = fc->s_fs_info;
 	struct jffs2_sb_info *c = JFFS2_SB_INFO(fc->root->d_sb);

 	mutex_lock(&c->alloc_sem);
 	if (new_c->mount_opts.override_compr) {
 		c->mount_opts.override_compr = new_c->mount_opts.override_compr;
 		c->mount_opts.compr = new_c->mount_opts.compr;
 	}
 	if (new_c->mount_opts.set_rp_size) {
 		c->mount_opts.set_rp_size = new_c->mount_opts.set_rp_size;
 		c->mount_opts.rp_size = new_c->mount_opts.rp_size;
 	}
 	mutex_unlock(&c->alloc_sem);
 }

 static int jffs2_reconfigure(struct fs_context *fc)
 {
 	struct super_block *sb = fc->root->d_sb;

 	sync_filesystem(sb);
 	jffs2_update_mount_opts(fc);

 	return jffs2_do_remount_fs(sb, fc);
 }

 static const struct super_operations jffs2_super_operations =
 {
 	.alloc_inode =	jffs2_alloc_inode,
 	.free_inode =	jffs2_free_inode,
 	.put_super =	jffs2_put_super,
 	.statfs =	jffs2_statfs,
 	.evict_inode =	jffs2_evict_inode,
 	.dirty_inode =	jffs2_dirty_inode,
 	.show_options =	jffs2_show_options,
 	.sync_fs =	jffs2_sync_fs,
 };

 /*
  * fill in the superblock
  */
 static int jffs2_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct jffs2_sb_info *c = sb->s_fs_info;

 	jffs2_dbg(1, "jffs2_get_sb_mtd():"
 		  " New superblock for device %d (\"%s\")\n",
 		  sb->s_mtd->index, sb->s_mtd->name);

 	c->mtd = sb->s_mtd;
 	c->os_priv = sb;

 	if (c->mount_opts.rp_size > c->mtd->size)
 		return invalf(fc, "jffs2: Too large reserve pool specified, max is %llu KB",
 			      c->mtd->size / 1024);

 	/* Initialize JFFS2 superblock locks, the further initialization will
 	 * be done later */
 	mutex_init(&c->alloc_sem);
 	mutex_init(&c->erase_free_sem);
 	init_waitqueue_head(&c->erase_wait);
 	init_waitqueue_head(&c->inocache_wq);
 	spin_lock_init(&c->erase_completion_lock);
 	spin_lock_init(&c->inocache_lock);

 	sb->s_op = &jffs2_super_operations;
 	sb->s_export_op = &jffs2_export_ops;
 	sb->s_flags = sb->s_flags | SB_NOATIME;
 	sb->s_xattr = jffs2_xattr_handlers;
 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 	sb->s_flags |= SB_POSIXACL;
 #endif
 	return jffs2_do_fill_super(sb, fc);
 }

 static int jffs2_get_tree(struct fs_context *fc)
 {
 	return get_tree_mtd(fc, jffs2_fill_super);
 }

 static void jffs2_free_fc(struct fs_context *fc)
 {
 	kfree(fc->s_fs_info);
 }

 static const struct fs_context_operations jffs2_context_ops = {
 	.free		= jffs2_free_fc,
 	.parse_param	= jffs2_parse_param,
 	.get_tree	= jffs2_get_tree,
 	.reconfigure	= jffs2_reconfigure,
 };

 static int jffs2_init_fs_context(struct fs_context *fc)
 {
 	struct jffs2_sb_info *ctx;

 	ctx = kzalloc(sizeof(struct jffs2_sb_info), GFP_KERNEL);
 	if (!ctx)
 		return -ENOMEM;

 	fc->s_fs_info = ctx;
 	fc->ops = &jffs2_context_ops;
 	return 0;
 }

 static void jffs2_put_super (struct super_block *sb)
 {
 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);

 	jffs2_dbg(2, "%s()\n", __func__);

 	mutex_lock(&c->alloc_sem);
 	jffs2_flush_wbuf_pad(c);
 	mutex_unlock(&c->alloc_sem);

 	jffs2_sum_exit(c);

 	jffs2_free_ino_caches(c);
 	jffs2_free_raw_node_refs(c);
 	kvfree(c->blocks);
 	jffs2_flash_cleanup(c);
 	kfree(c->inocache_list);
 	jffs2_clear_xattr_subsystem(c);
 	mtd_sync(c->mtd);
 	jffs2_dbg(1, "%s(): returning\n", __func__);
 }

 static void jffs2_kill_sb(struct super_block *sb)
 {
 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 	if (c && !sb_rdonly(sb))
 		jffs2_stop_garbage_collect_thread(c);
 	kill_mtd_super(sb);
 	kfree(c);
 }

 static struct file_system_type jffs2_fs_type = {
 	.owner =	THIS_MODULE,
 	.name =		"jffs2",
 	.init_fs_context = jffs2_init_fs_context,
 	.parameters =	jffs2_fs_parameters,
 	.kill_sb =	jffs2_kill_sb,
 };
 MODULE_ALIAS_FS("jffs2");

 static int __init init_jffs2_fs(void)
 {
 	int ret;

 	/* Paranoia checks for on-medium structures. If we ask GCC
 	   to pack them with __attribute__((packed)) then it _also_
 	   assumes that they're not aligned -- so it emits crappy
 	   code on some architectures. Ideally we want an attribute
 	   which means just 'no padding', without the alignment
 	   thing. But GCC doesn't have that -- we have to just
 	   hope the structs are the right sizes, instead. */
 	BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
 	BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
 	BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
 	BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);

 	pr_info("version 2.2."
 #ifdef CONFIG_JFFS2_FS_WRITEBUFFER
 	       " (NAND)"
 #endif
 #ifdef CONFIG_JFFS2_SUMMARY
 	       " (SUMMARY) "
 #endif
 	       " © 2001-2006 Red Hat, Inc.\n");

 	jffs2_inode_cachep = kmem_cache_create("jffs2_i",
 					     sizeof(struct jffs2_inode_info),
 					     0, (SLAB_RECLAIM_ACCOUNT|
 						SLAB_ACCOUNT),
 					     jffs2_i_init_once);
 	if (!jffs2_inode_cachep) {
 		pr_err("error: Failed to initialise inode cache\n");
 		return -ENOMEM;
 	}
 	ret = jffs2_compressors_init();
 	if (ret) {
 		pr_err("error: Failed to initialise compressors\n");
 		goto out;
 	}
 	ret = jffs2_create_slab_caches();
 	if (ret) {
 		pr_err("error: Failed to initialise slab caches\n");
 		goto out_compressors;
 	}
 	ret = register_filesystem(&jffs2_fs_type);
 	if (ret) {
 		pr_err("error: Failed to register filesystem\n");
 		goto out_slab;
 	}
 	return 0;

  out_slab:
 	jffs2_destroy_slab_caches();
  out_compressors:
 	jffs2_compressors_exit();
  out:
 	kmem_cache_destroy(jffs2_inode_cachep);
 	return ret;
 }

 static void __exit exit_jffs2_fs(void)
 {
 	unregister_filesystem(&jffs2_fs_type);
 	jffs2_destroy_slab_caches();
 	jffs2_compressors_exit();

 	/*
 	 * Make sure all delayed rcu free inodes are flushed before we
 	 * destroy cache.
 	 */
 	rcu_barrier();
 	kmem_cache_destroy(jffs2_inode_cachep);
 }

 module_init(init_jffs2_fs);
 module_exit(exit_jffs2_fs);

 MODULE_DESCRIPTION("The Journalling Flash File System, v2");
 MODULE_AUTHOR("Red Hat, Inc.");
 MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
 		       // the sake of this tag. It's Free Software.
	/*
	* JFFS2 -- Journalling Flash File System, Version 2.
	*
	* Copyright © 2001-2007 Red Hat, Inc.
	*
	* Created by David Woodhouse <dwmw2@infradead.org>
	*
	* For licensing information, see the file 'LICENCE' in this directory.
	*
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/init.h>
	#include <linux/list.h>
	#include <linux/fs.h>
	#include <linux/err.h>
	#include <linux/mount.h>
	#include <linux/fs_context.h>
	#include <linux/fs_parser.h>
	#include <linux/jffs2.h>
	#include <linux/pagemap.h>
	#include <linux/mtd/super.h>
	#include <linux/ctype.h>
	#include <linux/namei.h>
	#include <linux/seq_file.h>
	#include <linux/exportfs.h>
	#include "compr.h"
	#include "nodelist.h"

	static void jffs2_put_super(struct super_block *);

	static struct kmem_cache *jffs2_inode_cachep;

	static struct inode jffs2_alloc_inode(struct super_block sb)
	{
	struct jffs2_inode_info *f;

	f = alloc_inode_sb(sb, jffs2_inode_cachep, GFP_KERNEL);
	if (!f)
	return NULL;
	return &f->vfs_inode;
	}

	static void jffs2_free_inode(struct inode *inode)
	{
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);

	kfree(f->target);
	kmem_cache_free(jffs2_inode_cachep, f);
	}

	static void jffs2_i_init_once(void *foo)
	{
	struct jffs2_inode_info *f = foo;

	mutex_init(&f->sem);
	f->target = NULL;
	inode_init_once(&f->vfs_inode);
	}

	static const char *jffs2_compr_name(unsigned int compr)
	{
	switch (compr) {
	case JFFS2_COMPR_MODE_NONE:
	return "none";
	#ifdef CONFIG_JFFS2_LZO
	case JFFS2_COMPR_MODE_FORCELZO:
	return "lzo";
	#endif
	#ifdef CONFIG_JFFS2_ZLIB
	case JFFS2_COMPR_MODE_FORCEZLIB:
	return "zlib";
	#endif
	default:
	/* should never happen; programmer error */
	WARN_ON(1);
	return "";
	}
	}

	static int jffs2_show_options(struct seq_file s, struct dentry root)
	{
	struct jffs2_sb_info *c = JFFS2_SB_INFO(root->d_sb);
	struct jffs2_mount_opts *opts = &c->mount_opts;

	if (opts->override_compr)
	seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
	if (opts->set_rp_size)
	seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);

	return 0;
	}

	static int jffs2_sync_fs(struct super_block *sb, int wait)
	{
	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);

	#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
	if (jffs2_is_writebuffered(c))
	cancel_delayed_work_sync(&c->wbuf_dwork);
	#endif

	mutex_lock(&c->alloc_sem);
	jffs2_flush_wbuf_pad(c);
	mutex_unlock(&c->alloc_sem);
	return 0;
	}

	static struct inode jffs2_nfs_get_inode(struct super_block sb, uint64_t ino,
	uint32_t generation)
	{
	/* We don't care about i_generation. We'll destroy the flash
	before we start re-using inode numbers anyway. And even
	if that wasn't true, we'd have other problems...*/
	return jffs2_iget(sb, ino);
	}

	static struct dentry jffs2_fh_to_dentry(struct super_block sb, struct fid *fid,
	int fh_len, int fh_type)
	{
	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
	jffs2_nfs_get_inode);
	}

	static struct dentry jffs2_fh_to_parent(struct super_block sb, struct fid *fid,
	int fh_len, int fh_type)
	{
	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
	jffs2_nfs_get_inode);
	}

	static struct dentry jffs2_get_parent(struct dentry child)
	{
	struct jffs2_inode_info *f;
	uint32_t pino;

	BUG_ON(!d_is_dir(child));

	f = JFFS2_INODE_INFO(d_inode(child));

	pino = f->inocache->pino_nlink;

	JFFS2_DEBUG("Parent of directory ino #%u is #%u\n",
	f->inocache->ino, pino);

	return d_obtain_alias(jffs2_iget(child->d_sb, pino));
	}

	static const struct export_operations jffs2_export_ops = {
	.encode_fh = generic_encode_ino32_fh,
	.get_parent = jffs2_get_parent,
	.fh_to_dentry = jffs2_fh_to_dentry,
	.fh_to_parent = jffs2_fh_to_parent,
	};

	/*
	* JFFS2 mount options.
	*
	* Opt_source: The source device
	* Opt_override_compr: override default compressor
	* Opt_rp_size: size of reserved pool in KiB
	*/
	enum {
	Opt_override_compr,
	Opt_rp_size,
	};

	static const struct constant_table jffs2_param_compr[] = {
	{"none", JFFS2_COMPR_MODE_NONE },
	#ifdef CONFIG_JFFS2_LZO
	{"lzo", JFFS2_COMPR_MODE_FORCELZO },
	#endif
	#ifdef CONFIG_JFFS2_ZLIB
	{"zlib", JFFS2_COMPR_MODE_FORCEZLIB },
	#endif
	{}
	};

	static const struct fs_parameter_spec jffs2_fs_parameters[] = {
	fsparam_enum ("compr", Opt_override_compr, jffs2_param_compr),
	fsparam_u32 ("rp_size", Opt_rp_size),
	{}
	};

	static int jffs2_parse_param(struct fs_context fc, struct fs_parameter param)
	{
	struct fs_parse_result result;
	struct jffs2_sb_info *c = fc->s_fs_info;
	int opt;

	opt = fs_parse(fc, jffs2_fs_parameters, param, &result);
	if (opt < 0)
	return opt;

	switch (opt) {
	case Opt_override_compr:
	c->mount_opts.compr = result.uint_32;
	c->mount_opts.override_compr = true;
	break;
	case Opt_rp_size:
	if (result.uint_32 > UINT_MAX / 1024)
	return invalf(fc, "jffs2: rp_size unrepresentable");
	c->mount_opts.rp_size = result.uint_32 * 1024;
	c->mount_opts.set_rp_size = true;
	break;
	default:
	return -EINVAL;
	}

	return 0;
	}

	static inline void jffs2_update_mount_opts(struct fs_context *fc)
	{
	struct jffs2_sb_info *new_c = fc->s_fs_info;
	struct jffs2_sb_info *c = JFFS2_SB_INFO(fc->root->d_sb);

	mutex_lock(&c->alloc_sem);
	if (new_c->mount_opts.override_compr) {
	c->mount_opts.override_compr = new_c->mount_opts.override_compr;
	c->mount_opts.compr = new_c->mount_opts.compr;
	}
	if (new_c->mount_opts.set_rp_size) {
	c->mount_opts.set_rp_size = new_c->mount_opts.set_rp_size;
	c->mount_opts.rp_size = new_c->mount_opts.rp_size;
	}
	mutex_unlock(&c->alloc_sem);
	}

	static int jffs2_reconfigure(struct fs_context *fc)
	{
	struct super_block *sb = fc->root->d_sb;

	sync_filesystem(sb);
	jffs2_update_mount_opts(fc);

	return jffs2_do_remount_fs(sb, fc);
	}

	static const struct super_operations jffs2_super_operations =
	{
	.alloc_inode = jffs2_alloc_inode,
	.free_inode = jffs2_free_inode,
	.put_super = jffs2_put_super,
	.statfs = jffs2_statfs,
	.evict_inode = jffs2_evict_inode,
	.dirty_inode = jffs2_dirty_inode,
	.show_options = jffs2_show_options,
	.sync_fs = jffs2_sync_fs,
	};

	/*
	* fill in the superblock
	*/
	static int jffs2_fill_super(struct super_block sb, struct fs_context fc)
	{
	struct jffs2_sb_info *c = sb->s_fs_info;

	jffs2_dbg(1, "jffs2_get_sb_mtd():"
	" New superblock for device %d (\"%s\")\n",
	sb->s_mtd->index, sb->s_mtd->name);

	c->mtd = sb->s_mtd;
	c->os_priv = sb;

	if (c->mount_opts.rp_size > c->mtd->size)
	return invalf(fc, "jffs2: Too large reserve pool specified, max is %llu KB",
	c->mtd->size / 1024);

	/* Initialize JFFS2 superblock locks, the further initialization will
	* be done later */
	mutex_init(&c->alloc_sem);
	mutex_init(&c->erase_free_sem);
	init_waitqueue_head(&c->erase_wait);
	init_waitqueue_head(&c->inocache_wq);
	spin_lock_init(&c->erase_completion_lock);
	spin_lock_init(&c->inocache_lock);

	sb->s_op = &jffs2_super_operations;
	sb->s_export_op = &jffs2_export_ops;
	sb->s_flags = sb->s_flags \| SB_NOATIME;
	sb->s_xattr = jffs2_xattr_handlers;
	#ifdef CONFIG_JFFS2_FS_POSIX_ACL
	sb->s_flags \|= SB_POSIXACL;
	#endif
	return jffs2_do_fill_super(sb, fc);
	}

	static int jffs2_get_tree(struct fs_context *fc)
	{
	return get_tree_mtd(fc, jffs2_fill_super);
	}

	static void jffs2_free_fc(struct fs_context *fc)
	{
	kfree(fc->s_fs_info);
	}

	static const struct fs_context_operations jffs2_context_ops = {
	.free = jffs2_free_fc,
	.parse_param = jffs2_parse_param,
	.get_tree = jffs2_get_tree,
	.reconfigure = jffs2_reconfigure,
	};

	static int jffs2_init_fs_context(struct fs_context *fc)
	{
	struct jffs2_sb_info *ctx;

	ctx = kzalloc(sizeof(struct jffs2_sb_info), GFP_KERNEL);
	if (!ctx)
	return -ENOMEM;

	fc->s_fs_info = ctx;
	fc->ops = &jffs2_context_ops;
	return 0;
	}

	static void jffs2_put_super (struct super_block *sb)
	{
	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);

	jffs2_dbg(2, "%s()\n", __func__);

	mutex_lock(&c->alloc_sem);
	jffs2_flush_wbuf_pad(c);
	mutex_unlock(&c->alloc_sem);

	jffs2_sum_exit(c);

	jffs2_free_ino_caches(c);
	jffs2_free_raw_node_refs(c);
	kvfree(c->blocks);
	jffs2_flash_cleanup(c);
	kfree(c->inocache_list);
	jffs2_clear_xattr_subsystem(c);
	mtd_sync(c->mtd);
	jffs2_dbg(1, "%s(): returning\n", __func__);
	}

	static void jffs2_kill_sb(struct super_block *sb)
	{
	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
	if (c && !sb_rdonly(sb))
	jffs2_stop_garbage_collect_thread(c);
	kill_mtd_super(sb);
	kfree(c);
	}

	static struct file_system_type jffs2_fs_type = {
	.owner = THIS_MODULE,
	.name = "jffs2",
	.init_fs_context = jffs2_init_fs_context,
	.parameters = jffs2_fs_parameters,
	.kill_sb = jffs2_kill_sb,
	};
	MODULE_ALIAS_FS("jffs2");

	static int __init init_jffs2_fs(void)
	{
	int ret;

	/* Paranoia checks for on-medium structures. If we ask GCC
	to pack them with __attribute__((packed)) then it _also_
	assumes that they're not aligned -- so it emits crappy
	code on some architectures. Ideally we want an attribute
	which means just 'no padding', without the alignment
	thing. But GCC doesn't have that -- we have to just
	hope the structs are the right sizes, instead. */
	BUILD_BUG_ON(sizeof(struct jffs2_unknown_node) != 12);
	BUILD_BUG_ON(sizeof(struct jffs2_raw_dirent) != 40);
	BUILD_BUG_ON(sizeof(struct jffs2_raw_inode) != 68);
	BUILD_BUG_ON(sizeof(struct jffs2_raw_summary) != 32);

	pr_info("version 2.2."
	#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
	" (NAND)"
	#endif
	#ifdef CONFIG_JFFS2_SUMMARY
	" (SUMMARY) "
	#endif
	" © 2001-2006 Red Hat, Inc.\n");

	jffs2_inode_cachep = kmem_cache_create("jffs2_i",
	sizeof(struct jffs2_inode_info),
	0, (SLAB_RECLAIM_ACCOUNT\|
	SLAB_ACCOUNT),
	jffs2_i_init_once);
	if (!jffs2_inode_cachep) {
	pr_err("error: Failed to initialise inode cache\n");
	return -ENOMEM;
	}
	ret = jffs2_compressors_init();
	if (ret) {
	pr_err("error: Failed to initialise compressors\n");
	goto out;
	}
	ret = jffs2_create_slab_caches();
	if (ret) {
	pr_err("error: Failed to initialise slab caches\n");
	goto out_compressors;
	}
	ret = register_filesystem(&jffs2_fs_type);
	if (ret) {
	pr_err("error: Failed to register filesystem\n");
	goto out_slab;
	}
	return 0;

	out_slab:
	jffs2_destroy_slab_caches();
	out_compressors:
	jffs2_compressors_exit();
	out:
	kmem_cache_destroy(jffs2_inode_cachep);
	return ret;
	}

	static void __exit exit_jffs2_fs(void)
	{
	unregister_filesystem(&jffs2_fs_type);
	jffs2_destroy_slab_caches();
	jffs2_compressors_exit();

	/*
	* Make sure all delayed rcu free inodes are flushed before we
	* destroy cache.
	*/
	rcu_barrier();
	kmem_cache_destroy(jffs2_inode_cachep);
	}

	module_init(init_jffs2_fs);
	module_exit(exit_jffs2_fs);

	MODULE_DESCRIPTION("The Journalling Flash File System, v2");
	MODULE_AUTHOR("Red Hat, Inc.");
	MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
	// the sake of this tag. It's Free Software.