/*
   *  linux/fs/ufs/ialloc.c
   *
   * Copyright (c) 1998
   * Daniel Pirkl <daniel.pirkl@email.cz>
   * Charles University, Faculty of Mathematics and Physics
   *
   *  from
   *
   *  linux/fs/ext2/ialloc.c
   *
   * Copyright (C) 1992, 1993, 1994, 1995
   * Remy Card (card@masi.ibp.fr)
   * Laboratoire MASI - Institut Blaise Pascal
   * Universite Pierre et Marie Curie (Paris VI)
   *
   *  BSD ufs-inspired inode and directory allocation by 
   *  Stephen Tweedie (sct@dcs.ed.ac.uk), 1993
   *  Big-endian to little-endian byte-swapping/bitmaps by
   *        David S. Miller (davem@caip.rutgers.edu), 1995

   *
   * UFS2 write support added by
   * Evgeniy Dushistov <dushistov@mail.ru>, 2007

   */
  
  #include <linux/fs.h>

  #include <linux/time.h>
  #include <linux/stat.h>
  #include <linux/string.h>

  #include <linux/buffer_head.h>
  #include <linux/sched.h>
  #include <linux/bitops.h>
  #include <asm/byteorder.h>

  #include "ufs_fs.h"

  #include "ufs.h"

  #include "swab.h"
  #include "util.h"

  /*
   * NOTE! When we get the inode, we're the only people
   * that have access to it, and as such there are no
   * race conditions we have to worry about. The inode
   * is not on the hash-lists, and it cannot be reached
   * through the filesystem because the directory entry
   * has been deleted earlier.
   *
   * HOWEVER: we must make sure that we get no aliases,
   * which means that we have to call "clear_inode()"
   * _before_ we mark the inode not in use in the inode
   * bitmaps. Otherwise a newly created file might use
   * the same inode number (not actually the same pointer
   * though), and then we'd have two inodes sharing the
   * same inode number and space on the harddisk.
   */
  void ufs_free_inode (struct inode * inode)
  {
  	struct super_block * sb;
  	struct ufs_sb_private_info * uspi;
  	struct ufs_super_block_first * usb1;
  	struct ufs_cg_private_info * ucpi;
  	struct ufs_cylinder_group * ucg;
  	int is_directory;
  	unsigned ino, cg, bit;
  	

  	UFSD("ENTER, ino %lu
  ", inode->i_ino);

  
  	sb = inode->i_sb;
  	uspi = UFS_SB(sb)->s_uspi;

  	usb1 = ubh_get_usb_first(uspi);

  	
  	ino = inode->i_ino;
  
  	lock_super (sb);
  
  	if (!((ino > 1) && (ino < (uspi->s_ncg * uspi->s_ipg )))) {
  		ufs_warning(sb, "ufs_free_inode", "reserved inode or nonexistent inode %u
  ", ino);
  		unlock_super (sb);
  		return;
  	}
  	
  	cg = ufs_inotocg (ino);
  	bit = ufs_inotocgoff (ino);
  	ucpi = ufs_load_cylinder (sb, cg);
  	if (!ucpi) {
  		unlock_super (sb);
  		return;
  	}

  	ucg = ubh_get_ucg(UCPI_UBH(ucpi));

  	if (!ufs_cg_chkmagic(sb, ucg))
  		ufs_panic (sb, "ufs_free_fragments", "internal error, bad cg magic number");
  
  	ucg->cg_time = cpu_to_fs32(sb, get_seconds());
  
  	is_directory = S_ISDIR(inode->i_mode);

  	if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit))

  		ufs_error(sb, "ufs_free_inode", "bit already cleared for inode %u", ino);
  	else {

  		ubh_clrbit (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit);

  		if (ino < ucpi->c_irotor)
  			ucpi->c_irotor = ino;
  		fs32_add(sb, &ucg->cg_cs.cs_nifree, 1);

  		uspi->cs_total.cs_nifree++;

  		fs32_add(sb, &UFS_SB(sb)->fs_cs(cg).cs_nifree, 1);
  
  		if (is_directory) {
  			fs32_sub(sb, &ucg->cg_cs.cs_ndir, 1);

  			uspi->cs_total.cs_ndir--;

  			fs32_sub(sb, &UFS_SB(sb)->fs_cs(cg).cs_ndir, 1);
  		}
  	}

  	ubh_mark_buffer_dirty (USPI_UBH(uspi));
  	ubh_mark_buffer_dirty (UCPI_UBH(ucpi));

  	if (sb->s_flags & MS_SYNCHRONOUS)
  		ubh_sync_block(UCPI_UBH(ucpi));

  	
  	sb->s_dirt = 1;
  	unlock_super (sb);

  	UFSD("EXIT
  ");

  }
  
  /*

   * Nullify new chunk of inodes,
   * BSD people also set ui_gen field of inode
   * during nullification, but we not care about
   * that because of linux ufs do not support NFS
   */
  static void ufs2_init_inodes_chunk(struct super_block *sb,
  				   struct ufs_cg_private_info *ucpi,
  				   struct ufs_cylinder_group *ucg)
  {
  	struct buffer_head *bh;
  	struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
  	sector_t beg = uspi->s_sbbase +
  		ufs_inotofsba(ucpi->c_cgx * uspi->s_ipg +
  			      fs32_to_cpu(sb, ucg->cg_u.cg_u2.cg_initediblk));
  	sector_t end = beg + uspi->s_fpb;
  
  	UFSD("ENTER cgno %d
  ", ucpi->c_cgx);
  
  	for (; beg < end; ++beg) {
  		bh = sb_getblk(sb, beg);
  		lock_buffer(bh);
  		memset(bh->b_data, 0, sb->s_blocksize);
  		set_buffer_uptodate(bh);
  		mark_buffer_dirty(bh);
  		unlock_buffer(bh);
  		if (sb->s_flags & MS_SYNCHRONOUS)
  			sync_dirty_buffer(bh);
  		brelse(bh);
  	}
  
  	fs32_add(sb, &ucg->cg_u.cg_u2.cg_initediblk, uspi->s_inopb);
  	ubh_mark_buffer_dirty(UCPI_UBH(ucpi));

  	if (sb->s_flags & MS_SYNCHRONOUS)
  		ubh_sync_block(UCPI_UBH(ucpi));

  
  	UFSD("EXIT
  ");
  }
  
  /*

   * There are two policies for allocating an inode.  If the new inode is
   * a directory, then a forward search is made for a block group with both
   * free space and a low directory-to-inode ratio; if that fails, then of
   * the groups with above-average free space, that group with the fewest
   * directories already is chosen.
   *
   * For other inodes, search forward from the parent directory's block
   * group to find a free inode.
   */

  struct inode *ufs_new_inode(struct inode *dir, umode_t mode)

  {
  	struct super_block * sb;
  	struct ufs_sb_info * sbi;
  	struct ufs_sb_private_info * uspi;
  	struct ufs_super_block_first * usb1;
  	struct ufs_cg_private_info * ucpi;
  	struct ufs_cylinder_group * ucg;
  	struct inode * inode;
  	unsigned cg, bit, i, j, start;
  	struct ufs_inode_info *ufsi;

  	int err = -ENOSPC;

  	UFSD("ENTER
  ");

  	
  	/* Cannot create files in a deleted directory */
  	if (!dir || !dir->i_nlink)
  		return ERR_PTR(-EPERM);
  	sb = dir->i_sb;
  	inode = new_inode(sb);
  	if (!inode)
  		return ERR_PTR(-ENOMEM);
  	ufsi = UFS_I(inode);
  	sbi = UFS_SB(sb);
  	uspi = sbi->s_uspi;

  	usb1 = ubh_get_usb_first(uspi);

  
  	lock_super (sb);
  
  	/*
  	 * Try to place the inode in its parent directory
  	 */
  	i = ufs_inotocg(dir->i_ino);
  	if (sbi->fs_cs(i).cs_nifree) {
  		cg = i;
  		goto cg_found;
  	}
  
  	/*
  	 * Use a quadratic hash to find a group with a free inode
  	 */
  	for ( j = 1; j < uspi->s_ncg; j <<= 1 ) {
  		i += j;
  		if (i >= uspi->s_ncg)
  			i -= uspi->s_ncg;
  		if (sbi->fs_cs(i).cs_nifree) {
  			cg = i;
  			goto cg_found;
  		}
  	}
  
  	/*
  	 * That failed: try linear search for a free inode
  	 */
  	i = ufs_inotocg(dir->i_ino) + 1;
  	for (j = 2; j < uspi->s_ncg; j++) {
  		i++;
  		if (i >= uspi->s_ncg)
  			i = 0;
  		if (sbi->fs_cs(i).cs_nifree) {
  			cg = i;
  			goto cg_found;
  		}
  	}

  	goto failed;
  
  cg_found:
  	ucpi = ufs_load_cylinder (sb, cg);

  	if (!ucpi) {
  		err = -EIO;

  		goto failed;

  	}

  	ucg = ubh_get_ucg(UCPI_UBH(ucpi));

  	if (!ufs_cg_chkmagic(sb, ucg)) 
  		ufs_panic (sb, "ufs_new_inode", "internal error, bad cg magic number");
  
  	start = ucpi->c_irotor;

  	bit = ubh_find_next_zero_bit (UCPI_UBH(ucpi), ucpi->c_iusedoff, uspi->s_ipg, start);

  	if (!(bit < uspi->s_ipg)) {

  		bit = ubh_find_first_zero_bit (UCPI_UBH(ucpi), ucpi->c_iusedoff, start);

  		if (!(bit < start)) {
  			ufs_error (sb, "ufs_new_inode",
  			    "cylinder group %u corrupted - error in inode bitmap
  ", cg);

  			err = -EIO;

  			goto failed;
  		}
  	}

  	UFSD("start = %u, bit = %u, ipg = %u
  ", start, bit, uspi->s_ipg);

  	if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit))
  		ubh_setbit (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit);

  	else {
  		ufs_panic (sb, "ufs_new_inode", "internal error");

  		err = -EIO;

  		goto failed;
  	}

  
  	if (uspi->fs_magic == UFS2_MAGIC) {
  		u32 initediblk = fs32_to_cpu(sb, ucg->cg_u.cg_u2.cg_initediblk);
  
  		if (bit + uspi->s_inopb > initediblk &&
  		    initediblk < fs32_to_cpu(sb, ucg->cg_u.cg_u2.cg_niblk))
  			ufs2_init_inodes_chunk(sb, ucpi, ucg);
  	}

  	fs32_sub(sb, &ucg->cg_cs.cs_nifree, 1);

  	uspi->cs_total.cs_nifree--;

  	fs32_sub(sb, &sbi->fs_cs(cg).cs_nifree, 1);
  	
  	if (S_ISDIR(mode)) {
  		fs32_add(sb, &ucg->cg_cs.cs_ndir, 1);

  		uspi->cs_total.cs_ndir++;

  		fs32_add(sb, &sbi->fs_cs(cg).cs_ndir, 1);
  	}

  	ubh_mark_buffer_dirty (USPI_UBH(uspi));
  	ubh_mark_buffer_dirty (UCPI_UBH(ucpi));

  	if (sb->s_flags & MS_SYNCHRONOUS)
  		ubh_sync_block(UCPI_UBH(ucpi));

  	sb->s_dirt = 1;

  	inode->i_ino = cg * uspi->s_ipg + bit;

  	inode_init_owner(inode, dir, mode);

  	inode->i_blocks = 0;

  	inode->i_generation = 0;

  	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
  	ufsi->i_flags = UFS_I(dir)->i_flags;
  	ufsi->i_lastfrag = 0;

  	ufsi->i_shadow = 0;
  	ufsi->i_osync = 0;
  	ufsi->i_oeftflag = 0;

  	ufsi->i_dir_start_lookup = 0;

  	memset(&ufsi->i_u1, 0, sizeof(ufsi->i_u1));

  	insert_inode_hash(inode);
  	mark_inode_dirty(inode);

  	if (uspi->fs_magic == UFS2_MAGIC) {
  		struct buffer_head *bh;
  		struct ufs2_inode *ufs2_inode;
  
  		/*
  		 * setup birth date, we do it here because of there is no sense
  		 * to hold it in struct ufs_inode_info, and lose 64 bit
  		 */
  		bh = sb_bread(sb, uspi->s_sbbase + ufs_inotofsba(inode->i_ino));
  		if (!bh) {
  			ufs_warning(sb, "ufs_read_inode",
  				    "unable to read inode %lu
  ",
  				    inode->i_ino);
  			err = -EIO;
  			goto fail_remove_inode;
  		}
  		lock_buffer(bh);
  		ufs2_inode = (struct ufs2_inode *)bh->b_data;
  		ufs2_inode += ufs_inotofsbo(inode->i_ino);

  		ufs2_inode->ui_birthtime = cpu_to_fs64(sb, CURRENT_TIME.tv_sec);
  		ufs2_inode->ui_birthnsec = cpu_to_fs32(sb, CURRENT_TIME.tv_nsec);

  		mark_buffer_dirty(bh);
  		unlock_buffer(bh);
  		if (sb->s_flags & MS_SYNCHRONOUS)
  			sync_dirty_buffer(bh);
  		brelse(bh);
  	}

  	unlock_super (sb);

  	UFSD("allocating inode %lu
  ", inode->i_ino);
  	UFSD("EXIT
  ");

  	return inode;

  fail_remove_inode:
  	unlock_super(sb);

  	clear_nlink(inode);

  	iput(inode);
  	UFSD("EXIT (FAILED): err %d
  ", err);
  	return ERR_PTR(err);

  failed:
  	unlock_super (sb);
  	make_bad_inode(inode);
  	iput (inode);

  	UFSD("EXIT (FAILED): err %d
  ", err);
  	return ERR_PTR(err);

  }