/*
   * 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/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 = kmem_cache_alloc(jffs2_inode_cachep, GFP_KERNEL);
  	if (!f)

  		return NULL;

  	return &f->vfs_inode;

  }

  static void jffs2_i_callback(struct rcu_head *head)

  {

  	struct inode *inode = container_of(head, struct inode, i_rcu);

  	kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
  }

  static void jffs2_destroy_inode(struct inode *inode)
  {
  	call_rcu(&inode->i_rcu, jffs2_i_callback);
  }

  static void jffs2_i_init_once(void *foo)

  {

  	struct jffs2_inode_info *f = foo;

  	mutex_init(&f->sem);
  	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->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
  	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
  ",
  		    f->inocache->ino, pino);

  	return d_obtain_alias(jffs2_iget(d_inode(child)->i_sb, pino));

  }

  static const struct export_operations jffs2_export_ops = {

  	.get_parent = jffs2_get_parent,
  	.fh_to_dentry = jffs2_fh_to_dentry,
  	.fh_to_parent = jffs2_fh_to_parent,
  };

  /*
   * JFFS2 mount options.
   *
   * Opt_override_compr: override default compressor

   * Opt_rp_size: size of reserved pool in KiB

   * Opt_err: just end of array marker
   */
  enum {
  	Opt_override_compr,

  	Opt_rp_size,

  	Opt_err,
  };
  
  static const match_table_t tokens = {
  	{Opt_override_compr, "compr=%s"},

  	{Opt_rp_size, "rp_size=%u"},

  	{Opt_err, NULL},
  };
  
  static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
  {
  	substring_t args[MAX_OPT_ARGS];
  	char *p, *name;

  	unsigned int opt;

  
  	if (!data)
  		return 0;
  
  	while ((p = strsep(&data, ","))) {
  		int token;
  
  		if (!*p)
  			continue;
  
  		token = match_token(p, tokens, args);
  		switch (token) {
  		case Opt_override_compr:
  			name = match_strdup(&args[0]);
  
  			if (!name)
  				return -ENOMEM;

  			if (!strcmp(name, "none"))

  				c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;

  #ifdef CONFIG_JFFS2_LZO
  			else if (!strcmp(name, "lzo"))
  				c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
  #endif
  #ifdef CONFIG_JFFS2_ZLIB
  			else if (!strcmp(name, "zlib"))
  				c->mount_opts.compr =
  						JFFS2_COMPR_MODE_FORCEZLIB;
  #endif
  			else {

  				pr_err("Error: unknown compressor \"%s\"
  ",

  				       name);

  				kfree(name);
  				return -EINVAL;

  			}
  			kfree(name);

  			c->mount_opts.override_compr = true;

  			break;

  		case Opt_rp_size:
  			if (match_int(&args[0], &opt))
  				return -EINVAL;
  			opt *= 1024;
  			if (opt > c->mtd->size) {
  				pr_warn("Too large reserve pool specified, max "
  					"is %llu KB
  ", c->mtd->size / 1024);
  				return -EINVAL;
  			}
  			c->mount_opts.rp_size = opt;
  			break;

  		default:

  			pr_err("Error: unrecognized mount option '%s' or missing value
  ",

  			       p);

  			return -EINVAL;
  		}
  	}
  
  	return 0;
  }
  
  static int jffs2_remount_fs(struct super_block *sb, int *flags, char *data)
  {
  	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
  	int err;

  	sync_filesystem(sb);

  	err = jffs2_parse_options(c, data);
  	if (err)
  		return -EINVAL;
  
  	return jffs2_do_remount_fs(sb, flags, data);
  }

  static const struct super_operations jffs2_super_operations =

  {
  	.alloc_inode =	jffs2_alloc_inode,
  	.destroy_inode =jffs2_destroy_inode,

  	.put_super =	jffs2_put_super,

  	.statfs =	jffs2_statfs,
  	.remount_fs =	jffs2_remount_fs,

  	.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, void *data, int silent)

  {

  	struct jffs2_sb_info *c;

  	int ret;

  	jffs2_dbg(1, "jffs2_get_sb_mtd():"

  		  " New superblock for device %d (\"%s\")
  ",

  		  sb->s_mtd->index, sb->s_mtd->name);

  	c = kzalloc(sizeof(*c), GFP_KERNEL);

  	if (!c)

  		return -ENOMEM;

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

  	ret = jffs2_parse_options(c, data);
  	if (ret) {
  		kfree(c);
  		return -EINVAL;
  	}

  	/* 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 | 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, silent);

  	return ret;

  }

  static struct dentry *jffs2_mount(struct file_system_type *fs_type,

  			int flags, const char *dev_name,

  			void *data)

  {

  	return mount_mtd(fs_type, flags, dev_name, data, jffs2_fill_super);

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

  	jffs2_dbg(2, "%s()
  ", __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
  ", __func__);

  }
  
  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);

  	kill_mtd_super(sb);

  	kfree(c);
  }
  
  static struct file_system_type jffs2_fs_type = {
  	.owner =	THIS_MODULE,
  	.name =		"jffs2",

  	.mount =	jffs2_mount,

  	.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.
  ");

  
  	jffs2_inode_cachep = kmem_cache_create("jffs2_i",
  					     sizeof(struct jffs2_inode_info),

  					     0, (SLAB_RECLAIM_ACCOUNT|

  						SLAB_MEM_SPREAD|SLAB_ACCOUNT),

  					     jffs2_i_init_once);

  	if (!jffs2_inode_cachep) {

  		pr_err("error: Failed to initialise inode cache
  ");

  		return -ENOMEM;
  	}
  	ret = jffs2_compressors_init();
  	if (ret) {

  		pr_err("error: Failed to initialise compressors
  ");

  		goto out;
  	}
  	ret = jffs2_create_slab_caches();
  	if (ret) {

  		pr_err("error: Failed to initialise slab caches
  ");

  		goto out_compressors;
  	}
  	ret = register_filesystem(&jffs2_fs_type);
  	if (ret) {

  		pr_err("error: Failed to register filesystem
  ");

  		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.