/*
   * Super block/filesystem wide operations
   *
   * Copyright (C) 1996 Peter J. Braam <braam@maths.ox.ac.uk> and 
   * Michael Callahan <callahan@maths.ox.ac.uk> 
   * 
   * Rewritten for Linux 2.1.  Peter Braam <braam@cs.cmu.edu>
   * Copyright (C) Carnegie Mellon University
   */
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/mm.h>
  #include <linux/string.h>
  #include <linux/stat.h>
  #include <linux/errno.h>
  #include <linux/unistd.h>

  #include <linux/mutex.h>

  #include <linux/spinlock.h>

  #include <linux/file.h>
  #include <linux/vfs.h>

  #include <linux/slab.h>

  #include <linux/pid_namespace.h>

  #include <linux/uaccess.h>

  #include <linux/fs.h>
  #include <linux/vmalloc.h>
  
  #include <linux/coda.h>

  #include <linux/coda_psdev.h>

  #include "coda_linux.h"
  #include "coda_cache.h"

  #include "coda_int.h"

  /* VFS super_block ops */

  static void coda_evict_inode(struct inode *);

  static void coda_put_super(struct super_block *);

  static int coda_statfs(struct dentry *dentry, struct kstatfs *buf);

  static struct kmem_cache * coda_inode_cachep;

  
  static struct inode *coda_alloc_inode(struct super_block *sb)
  {
  	struct coda_inode_info *ei;

  	ei = kmem_cache_alloc(coda_inode_cachep, GFP_KERNEL);

  	if (!ei)
  		return NULL;
  	memset(&ei->c_fid, 0, sizeof(struct CodaFid));
  	ei->c_flags = 0;

  	ei->c_uid = GLOBAL_ROOT_UID;

  	ei->c_cached_perm = 0;

  	spin_lock_init(&ei->c_lock);

  	return &ei->vfs_inode;
  }

  static void coda_i_callback(struct rcu_head *head)

  {

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

  	kmem_cache_free(coda_inode_cachep, ITOC(inode));
  }

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

  static void init_once(void *foo)

  {
  	struct coda_inode_info *ei = (struct coda_inode_info *) foo;

  	inode_init_once(&ei->vfs_inode);

  }

  int __init coda_init_inodecache(void)

  {
  	coda_inode_cachep = kmem_cache_create("coda_inode_cache",

  				sizeof(struct coda_inode_info), 0,
  				SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
  				SLAB_ACCOUNT, init_once);

  	if (coda_inode_cachep == NULL)
  		return -ENOMEM;
  	return 0;
  }
  
  void coda_destroy_inodecache(void)
  {

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

  	kmem_cache_destroy(coda_inode_cachep);

  }
  
  static int coda_remount(struct super_block *sb, int *flags, char *data)
  {

  	sync_filesystem(sb);

  	*flags |= MS_NOATIME;

  	return 0;
  }
  
  /* exported operations */

  static const struct super_operations coda_super_operations =

  {
  	.alloc_inode	= coda_alloc_inode,
  	.destroy_inode	= coda_destroy_inode,

  	.evict_inode	= coda_evict_inode,

  	.put_super	= coda_put_super,
  	.statfs		= coda_statfs,
  	.remount_fs	= coda_remount,
  };
  
  static int get_device_index(struct coda_mount_data *data)
  {

  	struct fd f;

  	struct inode *inode;

  	int idx;

  	if (data == NULL) {

  		pr_warn("%s: Bad mount data
  ", __func__);

  		return -1;
  	}

  	if (data->version != CODA_MOUNT_VERSION) {

  		pr_warn("%s: Bad mount version
  ", __func__);

  		return -1;
  	}

  	f = fdget(data->fd);
  	if (!f.file)

  		goto Ebadf;

  	inode = file_inode(f.file);

  	if (!S_ISCHR(inode->i_mode) || imajor(inode) != CODA_PSDEV_MAJOR) {

  		fdput(f);

  		goto Ebadf;

  	}
  
  	idx = iminor(inode);

  	fdput(f);

  	if (idx < 0 || idx >= MAX_CODADEVS) {

  		pr_warn("%s: Bad minor number
  ", __func__);

  		return -1;
  	}
  
  	return idx;

  Ebadf:

  	pr_warn("%s: Bad file
  ", __func__);

  	return -1;

  }
  
  static int coda_fill_super(struct super_block *sb, void *data, int silent)
  {

  	struct inode *root = NULL;

  	struct venus_comm *vc;

  	struct CodaFid fid;

  	int error;

  	int idx;

  	if (task_active_pid_ns(current) != &init_pid_ns)
  		return -EINVAL;

  	idx = get_device_index((struct coda_mount_data *) data);
  
  	/* Ignore errors in data, for backward compatibility */
  	if(idx == -1)
  		idx = 0;
  	

  	pr_info("%s: device index: %i
  ", __func__,  idx);

  
  	vc = &coda_comms[idx];

  	mutex_lock(&vc->vc_mutex);

  	if (!vc->vc_inuse) {

  		pr_warn("%s: No pseudo device
  ", __func__);

  		error = -EINVAL;
  		goto unlock_out;

  	}

  	if (vc->vc_sb) {

  		pr_warn("%s: Device already mounted
  ", __func__);

  		error = -EBUSY;
  		goto unlock_out;

  	}

  	error = bdi_setup_and_register(&vc->bdi, "coda");

  	if (error)

  		goto unlock_out;

  	vc->vc_sb = sb;

  	mutex_unlock(&vc->vc_mutex);

  	sb->s_fs_info = vc;

  	sb->s_flags |= MS_NOATIME;
  	sb->s_blocksize = 4096;	/* XXXXX  what do we put here?? */
  	sb->s_blocksize_bits = 12;
  	sb->s_magic = CODA_SUPER_MAGIC;
  	sb->s_op = &coda_super_operations;

  	sb->s_d_op = &coda_dentry_operations;

  	sb->s_bdi = &vc->bdi;

  
  	/* get root fid from Venus: this needs the root inode */
  	error = venus_rootfid(sb, &fid);
  	if ( error ) {

  		pr_warn("%s: coda_get_rootfid failed with %d
  ",
  			__func__, error);

  		goto error;
  	}

  	pr_info("%s: rootfid is %s
  ", __func__, coda_f2s(&fid));

  	
  	/* make root inode */

          root = coda_cnode_make(&fid, sb);
          if (IS_ERR(root)) {
  		error = PTR_ERR(root);

  		pr_warn("Failure of coda_cnode_make for root: error %d
  ",
  			error);

  		goto error;

  	} 

  	pr_info("%s: rootinode is %ld dev %s
  ",
  		__func__, root->i_ino, root->i_sb->s_id);

  	sb->s_root = d_make_root(root);

  	if (!sb->s_root) {
  		error = -EINVAL;

  		goto error;

  	}

  	return 0;

  error:

  	mutex_lock(&vc->vc_mutex);

  	bdi_destroy(&vc->bdi);
  	vc->vc_sb = NULL;
  	sb->s_fs_info = NULL;
  unlock_out:

  	mutex_unlock(&vc->vc_mutex);

  	return error;

  }
  
  static void coda_put_super(struct super_block *sb)
  {

  	struct venus_comm *vcp = coda_vcp(sb);
  	mutex_lock(&vcp->vc_mutex);
  	bdi_destroy(&vcp->bdi);
  	vcp->vc_sb = NULL;

  	sb->s_fs_info = NULL;

  	mutex_unlock(&vcp->vc_mutex);

  	pr_info("Bye bye.
  ");

  }

  static void coda_evict_inode(struct inode *inode)

  {

  	truncate_inode_pages_final(&inode->i_data);

  	clear_inode(inode);

  	coda_cache_clear_inode(inode);
  }
  
  int coda_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
  {

  	int err = coda_revalidate_inode(d_inode(dentry));

  	if (!err)

  		generic_fillattr(d_inode(dentry), stat);

  	return err;
  }
  
  int coda_setattr(struct dentry *de, struct iattr *iattr)
  {

  	struct inode *inode = d_inode(de);

  	struct coda_vattr vattr;
  	int error;

  	memset(&vattr, 0, sizeof(vattr)); 

  	inode->i_ctime = current_time(inode);

  	coda_iattr_to_vattr(iattr, &vattr);
  	vattr.va_type = C_VNON; /* cannot set type */
  
  	/* Venus is responsible for truncating the container-file!!! */
  	error = venus_setattr(inode->i_sb, coda_i2f(inode), &vattr);

  	if (!error) {

  	        coda_vattr_to_iattr(inode, &vattr); 
  		coda_cache_clear_inode(inode);
  	}

  	return error;
  }

  const struct inode_operations coda_file_inode_operations = {

  	.permission	= coda_permission,
  	.getattr	= coda_getattr,
  	.setattr	= coda_setattr,
  };

  static int coda_statfs(struct dentry *dentry, struct kstatfs *buf)

  {
  	int error;
  	

  	error = venus_statfs(dentry, buf);

  	if (error) {
  		/* fake something like AFS does */
  		buf->f_blocks = 9000000;
  		buf->f_bfree  = 9000000;
  		buf->f_bavail = 9000000;
  		buf->f_files  = 9000000;
  		buf->f_ffree  = 9000000;
  	}
  
  	/* and fill in the rest */
  	buf->f_type = CODA_SUPER_MAGIC;

  	buf->f_bsize = 4096;

  	buf->f_namelen = CODA_MAXNAMLEN;
  
  	return 0; 
  }
  
  /* init_coda: used by filesystems.c to register coda */

  static struct dentry *coda_mount(struct file_system_type *fs_type,
  	int flags, const char *dev_name, void *data)

  {

  	return mount_nodev(fs_type, flags, data, coda_fill_super);

  }
  
  struct file_system_type coda_fs_type = {
  	.owner		= THIS_MODULE,
  	.name		= "coda",

  	.mount		= coda_mount,

  	.kill_sb	= kill_anon_super,
  	.fs_flags	= FS_BINARY_MOUNTDATA,
  };

  MODULE_ALIAS_FS("coda");