/*
   * Copyright (c) 2000-2001 Christoph Hellwig.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions, and the following disclaimer,
   *    without modification.
   * 2. The name of the author may not be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   *
   * Alternatively, this software may be distributed under the terms of the
   * GNU General Public License ("GPL").
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
   * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  /*
   * Veritas filesystem driver - inode routines.
   */
  #include <linux/fs.h>
  #include <linux/buffer_head.h>
  #include <linux/pagemap.h>
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/namei.h>
  
  #include "vxfs.h"
  #include "vxfs_inode.h"
  #include "vxfs_extern.h"
  
  
  struct kmem_cache		*vxfs_inode_cachep;
  
  
  #ifdef DIAGNOSTIC
  /*
   * Dump inode contents (partially).
   */
  void
  vxfs_dumpi(struct vxfs_inode_info *vip, ino_t ino)
  {
  	printk(KERN_DEBUG "
  
  ");
  	if (ino)
  		printk(KERN_DEBUG "dumping vxfs inode %ld
  ", ino);
  	else
  		printk(KERN_DEBUG "dumping unknown vxfs inode
  ");
  
  	printk(KERN_DEBUG "---------------------------
  ");
  	printk(KERN_DEBUG "mode is %x
  ", vip->vii_mode);
  	printk(KERN_DEBUG "nlink:%u, uid:%u, gid:%u
  ",
  			vip->vii_nlink, vip->vii_uid, vip->vii_gid);
  	printk(KERN_DEBUG "size:%Lx, blocks:%u
  ",
  			vip->vii_size, vip->vii_blocks);
  	printk(KERN_DEBUG "orgtype:%u
  ", vip->vii_orgtype);
  }
  #endif
  
  
  /**
   * vxfs_blkiget - find inode based on extent #
   * @sbp:	superblock of the filesystem we search in
   * @extent:	number of the extent to search
   * @ino:	inode number to search
   *
   * Description:
   *  vxfs_blkiget searches inode @ino in the filesystem described by
   *  @sbp in the extent @extent.
   *  Returns the matching VxFS inode on success, else a NULL pointer.
   *
   * NOTE:
   *  While __vxfs_iget uses the pagecache vxfs_blkiget uses the
   *  buffercache.  This function should not be used outside the
   *  read_super() method, otherwise the data may be incoherent.
   */
  struct vxfs_inode_info *
  vxfs_blkiget(struct super_block *sbp, u_long extent, ino_t ino)
  {
  	struct buffer_head		*bp;
  	u_long				block, offset;
  
  	block = extent + ((ino * VXFS_ISIZE) / sbp->s_blocksize);
  	offset = ((ino % (sbp->s_blocksize / VXFS_ISIZE)) * VXFS_ISIZE);
  	bp = sb_bread(sbp, block);
  
  	if (bp && buffer_mapped(bp)) {
  		struct vxfs_inode_info	*vip;
  		struct vxfs_dinode	*dip;
  
  		if (!(vip = kmem_cache_alloc(vxfs_inode_cachep, GFP_KERNEL)))
  			goto fail;
  		dip = (struct vxfs_dinode *)(bp->b_data + offset);
  		memcpy(vip, dip, sizeof(*vip));
  #ifdef DIAGNOSTIC
  		vxfs_dumpi(vip, ino);
  #endif
  		brelse(bp);
  		return (vip);
  	}
  
  fail:
  	printk(KERN_WARNING "vxfs: unable to read block %ld
  ", block);
  	brelse(bp);
  	return NULL;
  }
  
  /**
   * __vxfs_iget - generic find inode facility
   * @sbp:		VFS superblock
   * @ino:		inode number
   * @ilistp:		inode list
   *
   * Description:
   *  Search the for inode number @ino in the filesystem
   *  described by @sbp.  Use the specified inode table (@ilistp).
   *  Returns the matching VxFS inode on success, else an error code.
   */
  static struct vxfs_inode_info *
  __vxfs_iget(ino_t ino, struct inode *ilistp)
  {
  	struct page			*pp;
  	u_long				offset;
  
  	offset = (ino % (PAGE_SIZE / VXFS_ISIZE)) * VXFS_ISIZE;
  	pp = vxfs_get_page(ilistp->i_mapping, ino * VXFS_ISIZE / PAGE_SIZE);
  
  	if (!IS_ERR(pp)) {
  		struct vxfs_inode_info	*vip;
  		struct vxfs_dinode	*dip;
  		caddr_t			kaddr = (char *)page_address(pp);
  
  		if (!(vip = kmem_cache_alloc(vxfs_inode_cachep, GFP_KERNEL)))
  			goto fail;
  		dip = (struct vxfs_dinode *)(kaddr + offset);
  		memcpy(vip, dip, sizeof(*vip));
  #ifdef DIAGNOSTIC
  		vxfs_dumpi(vip, ino);
  #endif
  		vxfs_put_page(pp);
  		return (vip);
  	}
  
  	printk(KERN_WARNING "vxfs: error on page %p
  ", pp);
  	return ERR_CAST(pp);
  
  fail:
  	printk(KERN_WARNING "vxfs: unable to read inode %ld
  ", (unsigned long)ino);
  	vxfs_put_page(pp);
  	return ERR_PTR(-ENOMEM);
  }
  
  /**
   * vxfs_stiget - find inode using the structural inode list
   * @sbp:	VFS superblock
   * @ino:	inode #
   *
   * Description:
   *  Find inode @ino in the filesystem described by @sbp using
   *  the structural inode list.
   *  Returns the matching VxFS inode on success, else a NULL pointer.
   */
  struct vxfs_inode_info *
  vxfs_stiget(struct super_block *sbp, ino_t ino)
  {
  	struct vxfs_inode_info *vip;
  
  	vip = __vxfs_iget(ino, VXFS_SBI(sbp)->vsi_stilist);
  	return IS_ERR(vip) ? NULL : vip;
  }
  
  /**
   * vxfs_transmod - mode for a VxFS inode
   * @vip:	VxFS inode
   *
   * Description:
   *  vxfs_transmod returns a Linux mode_t for a given
   *  VxFS inode structure.
   */
  static __inline__ umode_t
  vxfs_transmod(struct vxfs_inode_info *vip)
  {
  	umode_t			ret = vip->vii_mode & ~VXFS_TYPE_MASK;
  
  	if (VXFS_ISFIFO(vip))
  		ret |= S_IFIFO;
  	if (VXFS_ISCHR(vip))
  		ret |= S_IFCHR;
  	if (VXFS_ISDIR(vip))
  		ret |= S_IFDIR;
  	if (VXFS_ISBLK(vip))
  		ret |= S_IFBLK;
  	if (VXFS_ISLNK(vip))
  		ret |= S_IFLNK;
  	if (VXFS_ISREG(vip))
  		ret |= S_IFREG;
  	if (VXFS_ISSOC(vip))
  		ret |= S_IFSOCK;
  
  	return (ret);
  }
  
  /**
   * vxfs_iinit- helper to fill inode fields
   * @ip:		VFS inode
   * @vip:	VxFS inode
   *
   * Description:
   *  vxfs_instino is a helper function to fill in all relevant
   *  fields in @ip from @vip.
   */
  static void
  vxfs_iinit(struct inode *ip, struct vxfs_inode_info *vip)
  {
  
  	ip->i_mode = vxfs_transmod(vip);
  	i_uid_write(ip, (uid_t)vip->vii_uid);
  	i_gid_write(ip, (gid_t)vip->vii_gid);
  
  	set_nlink(ip, vip->vii_nlink);
  	ip->i_size = vip->vii_size;
  
  	ip->i_atime.tv_sec = vip->vii_atime;
  	ip->i_ctime.tv_sec = vip->vii_ctime;
  	ip->i_mtime.tv_sec = vip->vii_mtime;
  	ip->i_atime.tv_nsec = 0;
  	ip->i_ctime.tv_nsec = 0;
  	ip->i_mtime.tv_nsec = 0;
  
  	ip->i_blocks = vip->vii_blocks;
  	ip->i_generation = vip->vii_gen;
  
  	ip->i_private = vip;
  	
  }
  
  /**
   * vxfs_get_fake_inode - get fake inode structure
   * @sbp:		filesystem superblock
   * @vip:		fspriv inode
   *
   * Description:
   *  vxfs_fake_inode gets a fake inode (not in the inode hash) for a
   *  superblock, vxfs_inode pair.
   *  Returns the filled VFS inode.
   */
  struct inode *
  vxfs_get_fake_inode(struct super_block *sbp, struct vxfs_inode_info *vip)
  {
  	struct inode			*ip = NULL;
  
  	if ((ip = new_inode(sbp))) {
  		ip->i_ino = get_next_ino();
  		vxfs_iinit(ip, vip);
  		ip->i_mapping->a_ops = &vxfs_aops;
  	}
  	return (ip);
  }
  
  /**
   * vxfs_put_fake_inode - free faked inode
   * *ip:			VFS inode
   *
   * Description:
   *  vxfs_put_fake_inode frees all data associated with @ip.
   */
  void
  vxfs_put_fake_inode(struct inode *ip)
  {
  	iput(ip);
  }
  
  /**
   * vxfs_iget - get an inode
   * @sbp:	the superblock to get the inode for
   * @ino:	the number of the inode to get
   *
   * Description:
   *  vxfs_read_inode creates an inode, reads the disk inode for @ino and fills
   *  in all relevant fields in the new inode.
   */
  struct inode *
  vxfs_iget(struct super_block *sbp, ino_t ino)
  {
  	struct vxfs_inode_info		*vip;
  	const struct address_space_operations	*aops;
  	struct inode *ip;
  
  	ip = iget_locked(sbp, ino);
  	if (!ip)
  		return ERR_PTR(-ENOMEM);
  	if (!(ip->i_state & I_NEW))
  		return ip;
  
  	vip = __vxfs_iget(ino, VXFS_SBI(sbp)->vsi_ilist);
  	if (IS_ERR(vip)) {
  		iget_failed(ip);
  		return ERR_CAST(vip);
  	}
  
  	vxfs_iinit(ip, vip);
  
  	if (VXFS_ISIMMED(vip))
  		aops = &vxfs_immed_aops;
  	else
  		aops = &vxfs_aops;
  
  	if (S_ISREG(ip->i_mode)) {
  		ip->i_fop = &generic_ro_fops;
  		ip->i_mapping->a_ops = aops;
  	} else if (S_ISDIR(ip->i_mode)) {
  		ip->i_op = &vxfs_dir_inode_ops;
  		ip->i_fop = &vxfs_dir_operations;
  		ip->i_mapping->a_ops = aops;
  	} else if (S_ISLNK(ip->i_mode)) {
  		if (!VXFS_ISIMMED(vip)) {
  			ip->i_op = &page_symlink_inode_operations;
  			ip->i_mapping->a_ops = &vxfs_aops;
  		} else {
  			ip->i_op = &simple_symlink_inode_operations;
  			ip->i_link = vip->vii_immed.vi_immed;
  			nd_terminate_link(ip->i_link, ip->i_size,
  					  sizeof(vip->vii_immed.vi_immed) - 1);
  		}
  	} else
  		init_special_inode(ip, ip->i_mode, old_decode_dev(vip->vii_rdev));
  
  	unlock_new_inode(ip);
  	return ip;
  }
  
  static void vxfs_i_callback(struct rcu_head *head)
  {
  	struct inode *inode = container_of(head, struct inode, i_rcu);
  	kmem_cache_free(vxfs_inode_cachep, inode->i_private);
  }
  
  /**
   * vxfs_evict_inode - remove inode from main memory
   * @ip:		inode to discard.
   *
   * Description:
   *  vxfs_evict_inode() is called on the final iput and frees the private
   *  inode area.
   */
  void
  vxfs_evict_inode(struct inode *ip)
  {
  	truncate_inode_pages_final(&ip->i_data);
  	clear_inode(ip);
  	call_rcu(&ip->i_rcu, vxfs_i_callback);
  }