/*

   * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
   * All Rights Reserved.

   *

   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License as

   * published by the Free Software Foundation.
   *

   * This program is distributed in the hope that it would be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.

   *

   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write the Free Software Foundation,
   * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

   */

  #include "xfs.h"

  #include "xfs_fs.h"

  #include "xfs_types.h"

  #include "xfs_bit.h"

  #include "xfs_log.h"

  #include "xfs_inum.h"

  #include "xfs_trans.h"
  #include "xfs_sb.h"
  #include "xfs_ag.h"

  #include "xfs_mount.h"

  #include "xfs_da_btree.h"

  #include "xfs_bmap_btree.h"

  #include "xfs_alloc_btree.h"

  #include "xfs_dinode.h"

  #include "xfs_inode.h"

  #include "xfs_inode_item.h"

  #include "xfs_bmap.h"

  #include "xfs_dir2.h"
  #include "xfs_dir2_format.h"
  #include "xfs_dir2_priv.h"

  #include "xfs_error.h"

  #include "xfs_vnodeops.h"

  #include "xfs_trace.h"

  struct xfs_name xfs_name_dotdot = { (unsigned char *)"..", 2};

  /*
   * ASCII case-insensitive (ie. A-Z) support for directories that was
   * used in IRIX.
   */
  STATIC xfs_dahash_t
  xfs_ascii_ci_hashname(
  	struct xfs_name	*name)
  {
  	xfs_dahash_t	hash;
  	int		i;
  
  	for (i = 0, hash = 0; i < name->len; i++)
  		hash = tolower(name->name[i]) ^ rol32(hash, 7);
  
  	return hash;
  }
  
  STATIC enum xfs_dacmp
  xfs_ascii_ci_compname(
  	struct xfs_da_args *args,

  	const unsigned char *name,
  	int		len)

  {
  	enum xfs_dacmp	result;
  	int		i;
  
  	if (args->namelen != len)
  		return XFS_CMP_DIFFERENT;
  
  	result = XFS_CMP_EXACT;
  	for (i = 0; i < len; i++) {
  		if (args->name[i] == name[i])
  			continue;
  		if (tolower(args->name[i]) != tolower(name[i]))
  			return XFS_CMP_DIFFERENT;
  		result = XFS_CMP_CASE;
  	}
  
  	return result;
  }
  
  static struct xfs_nameops xfs_ascii_ci_nameops = {
  	.hashname	= xfs_ascii_ci_hashname,
  	.compname	= xfs_ascii_ci_compname,
  };

  void
  xfs_dir_mount(
  	xfs_mount_t	*mp)

  {

  	ASSERT(xfs_sb_version_hasdirv2(&mp->m_sb));

  	ASSERT((1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) <=
  	       XFS_MAX_BLOCKSIZE);
  	mp->m_dirblksize = 1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog);
  	mp->m_dirblkfsbs = 1 << mp->m_sb.sb_dirblklog;

  	mp->m_dirdatablk = xfs_dir2_db_to_da(mp, XFS_DIR2_DATA_FIRSTDB(mp));
  	mp->m_dirleafblk = xfs_dir2_db_to_da(mp, XFS_DIR2_LEAF_FIRSTDB(mp));
  	mp->m_dirfreeblk = xfs_dir2_db_to_da(mp, XFS_DIR2_FREE_FIRSTDB(mp));

  	mp->m_attr_node_ents =
  		(mp->m_sb.sb_blocksize - (uint)sizeof(xfs_da_node_hdr_t)) /
  		(uint)sizeof(xfs_da_node_entry_t);
  	mp->m_dir_node_ents =
  		(mp->m_dirblksize - (uint)sizeof(xfs_da_node_hdr_t)) /
  		(uint)sizeof(xfs_da_node_entry_t);
  	mp->m_dir_magicpct = (mp->m_dirblksize * 37) / 100;

  	if (xfs_sb_version_hasasciici(&mp->m_sb))
  		mp->m_dirnameops = &xfs_ascii_ci_nameops;
  	else
  		mp->m_dirnameops = &xfs_default_nameops;

  }
  
  /*
   * Return 1 if directory contains only "." and "..".
   */

  int
  xfs_dir_isempty(
  	xfs_inode_t	*dp)

  {

  	xfs_dir2_sf_hdr_t	*sfp;

  	ASSERT(S_ISDIR(dp->i_d.di_mode));

  	if (dp->i_d.di_size == 0)	/* might happen during shutdown. */

  		return 1;

  	if (dp->i_d.di_size > XFS_IFORK_DSIZE(dp))
  		return 0;

  	sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
  	return !sfp->count;

  }
  
  /*

   * Validate a given inode number.
   */
  int
  xfs_dir_ino_validate(
  	xfs_mount_t	*mp,
  	xfs_ino_t	ino)
  {
  	xfs_agblock_t	agblkno;
  	xfs_agino_t	agino;
  	xfs_agnumber_t	agno;
  	int		ino_ok;
  	int		ioff;
  
  	agno = XFS_INO_TO_AGNO(mp, ino);
  	agblkno = XFS_INO_TO_AGBNO(mp, ino);
  	ioff = XFS_INO_TO_OFFSET(mp, ino);
  	agino = XFS_OFFBNO_TO_AGINO(mp, agblkno, ioff);
  	ino_ok =
  		agno < mp->m_sb.sb_agcount &&
  		agblkno < mp->m_sb.sb_agblocks &&
  		agblkno != 0 &&
  		ioff < (1 << mp->m_sb.sb_inopblog) &&
  		XFS_AGINO_TO_INO(mp, agno, agino) == ino;
  	if (unlikely(XFS_TEST_ERROR(!ino_ok, mp, XFS_ERRTAG_DIR_INO_VALIDATE,
  			XFS_RANDOM_DIR_INO_VALIDATE))) {

  		xfs_warn(mp, "Invalid inode number 0x%Lx",

  				(unsigned long long) ino);
  		XFS_ERROR_REPORT("xfs_dir_ino_validate", XFS_ERRLEVEL_LOW, mp);
  		return XFS_ERROR(EFSCORRUPTED);
  	}
  	return 0;
  }
  
  /*

   * Initialize a directory with its "." and ".." entries.
   */

  int
  xfs_dir_init(
  	xfs_trans_t	*tp,
  	xfs_inode_t	*dp,
  	xfs_inode_t	*pdp)

  {

  	xfs_da_args_t	args;
  	int		error;

  
  	memset((char *)&args, 0, sizeof(args));
  	args.dp = dp;
  	args.trans = tp;

  	ASSERT(S_ISDIR(dp->i_d.di_mode));

  	if ((error = xfs_dir_ino_validate(tp->t_mountp, pdp->i_ino)))

  		return error;

  	return xfs_dir2_sf_create(&args, pdp->i_ino);
  }
  
  /*
    Enter a name in a directory.
   */

  int
  xfs_dir_createname(
  	xfs_trans_t		*tp,
  	xfs_inode_t		*dp,

  	struct xfs_name		*name,

  	xfs_ino_t		inum,		/* new entry inode number */
  	xfs_fsblock_t		*first,		/* bmap's firstblock */
  	xfs_bmap_free_t		*flist,		/* bmap's freeblock list */
  	xfs_extlen_t		total)		/* bmap's total block count */
  {

  	xfs_da_args_t		args;
  	int			rval;

  	int			v;		/* type-checking value */

  	ASSERT(S_ISDIR(dp->i_d.di_mode));

  	if ((rval = xfs_dir_ino_validate(tp->t_mountp, inum)))

  		return rval;

  	XFS_STATS_INC(xs_dir_create);

  	memset(&args, 0, sizeof(xfs_da_args_t));

  	args.name = name->name;
  	args.namelen = name->len;

  	args.hashval = dp->i_mount->m_dirnameops->hashname(name);

  	args.inumber = inum;
  	args.dp = dp;
  	args.firstblock = first;
  	args.flist = flist;
  	args.total = total;
  	args.whichfork = XFS_DATA_FORK;
  	args.trans = tp;

  	args.op_flags = XFS_DA_OP_ADDNAME | XFS_DA_OP_OKNOENT;

  	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
  		rval = xfs_dir2_sf_addname(&args);

  	else if ((rval = xfs_dir2_isblock(tp, dp, &v)))

  		return rval;

  	else if (v)

  		rval = xfs_dir2_block_addname(&args);

  	else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))

  		return rval;

  	else if (v)

  		rval = xfs_dir2_leaf_addname(&args);
  	else
  		rval = xfs_dir2_node_addname(&args);
  	return rval;
  }
  
  /*

   * If doing a CI lookup and case-insensitive match, dup actual name into
   * args.value. Return EEXIST for success (ie. name found) or an error.
   */
  int
  xfs_dir_cilookup_result(
  	struct xfs_da_args *args,

  	const unsigned char *name,

  	int		len)
  {
  	if (args->cmpresult == XFS_CMP_DIFFERENT)
  		return ENOENT;
  	if (args->cmpresult != XFS_CMP_CASE ||
  					!(args->op_flags & XFS_DA_OP_CILOOKUP))
  		return EEXIST;

  	args->value = kmem_alloc(len, KM_NOFS | KM_MAYFAIL);

  	if (!args->value)
  		return ENOMEM;
  
  	memcpy(args->value, name, len);
  	args->valuelen = len;
  	return EEXIST;
  }
  
  /*

   * Lookup a name in a directory, give back the inode number.

   * If ci_name is not NULL, returns the actual name in ci_name if it differs
   * to name, or ci_name->name is set to NULL for an exact match.

   */

  int
  xfs_dir_lookup(
  	xfs_trans_t	*tp,
  	xfs_inode_t	*dp,

  	struct xfs_name	*name,

  	xfs_ino_t	*inum,		/* out: inode number */
  	struct xfs_name *ci_name)	/* out: actual name if CI match */

  {

  	xfs_da_args_t	args;
  	int		rval;

  	int		v;		/* type-checking value */

  	ASSERT(S_ISDIR(dp->i_d.di_mode));

  	XFS_STATS_INC(xs_dir_lookup);

  	memset(&args, 0, sizeof(xfs_da_args_t));

  	args.name = name->name;
  	args.namelen = name->len;

  	args.hashval = dp->i_mount->m_dirnameops->hashname(name);

  	args.dp = dp;

  	args.whichfork = XFS_DATA_FORK;
  	args.trans = tp;

  	args.op_flags = XFS_DA_OP_OKNOENT;

  	if (ci_name)
  		args.op_flags |= XFS_DA_OP_CILOOKUP;

  	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
  		rval = xfs_dir2_sf_lookup(&args);

  	else if ((rval = xfs_dir2_isblock(tp, dp, &v)))

  		return rval;

  	else if (v)

  		rval = xfs_dir2_block_lookup(&args);

  	else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))

  		return rval;

  	else if (v)

  		rval = xfs_dir2_leaf_lookup(&args);
  	else
  		rval = xfs_dir2_node_lookup(&args);
  	if (rval == EEXIST)
  		rval = 0;

  	if (!rval) {

  		*inum = args.inumber;

  		if (ci_name) {
  			ci_name->name = args.value;
  			ci_name->len = args.valuelen;
  		}
  	}

  	return rval;
  }
  
  /*
   * Remove an entry from a directory.
   */

  int
  xfs_dir_removename(
  	xfs_trans_t	*tp,
  	xfs_inode_t	*dp,

  	struct xfs_name	*name,

  	xfs_ino_t	ino,

  	xfs_fsblock_t	*first,		/* bmap's firstblock */
  	xfs_bmap_free_t	*flist,		/* bmap's freeblock list */
  	xfs_extlen_t	total)		/* bmap's total block count */
  {

  	xfs_da_args_t	args;
  	int		rval;

  	int		v;		/* type-checking value */

  	ASSERT(S_ISDIR(dp->i_d.di_mode));

  	XFS_STATS_INC(xs_dir_remove);

  	memset(&args, 0, sizeof(xfs_da_args_t));

  	args.name = name->name;
  	args.namelen = name->len;

  	args.hashval = dp->i_mount->m_dirnameops->hashname(name);

  	args.inumber = ino;
  	args.dp = dp;
  	args.firstblock = first;
  	args.flist = flist;
  	args.total = total;
  	args.whichfork = XFS_DATA_FORK;
  	args.trans = tp;

  	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
  		rval = xfs_dir2_sf_removename(&args);

  	else if ((rval = xfs_dir2_isblock(tp, dp, &v)))

  		return rval;

  	else if (v)

  		rval = xfs_dir2_block_removename(&args);

  	else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))

  		return rval;

  	else if (v)

  		rval = xfs_dir2_leaf_removename(&args);
  	else
  		rval = xfs_dir2_node_removename(&args);
  	return rval;
  }
  
  /*
   * Read a directory.
   */

  int

  xfs_readdir(

  	xfs_inode_t	*dp,

  	void		*dirent,
  	size_t		bufsize,
  	xfs_off_t	*offset,
  	filldir_t	filldir)

  {

  	int		rval;		/* return value */
  	int		v;		/* type-checking value */

  	trace_xfs_readdir(dp);

  
  	if (XFS_FORCED_SHUTDOWN(dp->i_mount))
  		return XFS_ERROR(EIO);

  	ASSERT(S_ISDIR(dp->i_d.di_mode));

  	XFS_STATS_INC(xs_dir_getdents);

  	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)

  		rval = xfs_dir2_sf_getdents(dp, dirent, offset, filldir);
  	else if ((rval = xfs_dir2_isblock(NULL, dp, &v)))

  		;

  	else if (v)

  		rval = xfs_dir2_block_getdents(dp, dirent, offset, filldir);

  	else

  		rval = xfs_dir2_leaf_getdents(dp, dirent, bufsize, offset,
  					      filldir);

  	return rval;
  }
  
  /*
   * Replace the inode number of a directory entry.
   */

  int
  xfs_dir_replace(
  	xfs_trans_t	*tp,
  	xfs_inode_t	*dp,

  	struct xfs_name	*name,		/* name of entry to replace */

  	xfs_ino_t	inum,		/* new inode number */
  	xfs_fsblock_t	*first,		/* bmap's firstblock */
  	xfs_bmap_free_t	*flist,		/* bmap's freeblock list */
  	xfs_extlen_t	total)		/* bmap's total block count */
  {

  	xfs_da_args_t	args;
  	int		rval;

  	int		v;		/* type-checking value */

  	ASSERT(S_ISDIR(dp->i_d.di_mode));

  	if ((rval = xfs_dir_ino_validate(tp->t_mountp, inum)))

  		return rval;

  	memset(&args, 0, sizeof(xfs_da_args_t));

  	args.name = name->name;
  	args.namelen = name->len;

  	args.hashval = dp->i_mount->m_dirnameops->hashname(name);

  	args.inumber = inum;
  	args.dp = dp;
  	args.firstblock = first;
  	args.flist = flist;
  	args.total = total;
  	args.whichfork = XFS_DATA_FORK;
  	args.trans = tp;

  	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
  		rval = xfs_dir2_sf_replace(&args);

  	else if ((rval = xfs_dir2_isblock(tp, dp, &v)))

  		return rval;

  	else if (v)

  		rval = xfs_dir2_block_replace(&args);

  	else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))

  		return rval;

  	else if (v)

  		rval = xfs_dir2_leaf_replace(&args);
  	else
  		rval = xfs_dir2_node_replace(&args);
  	return rval;
  }
  
  /*
   * See if this entry can be added to the directory without allocating space.

   * First checks that the caller couldn't reserve enough space (resblks = 0).

   */

  int
  xfs_dir_canenter(
  	xfs_trans_t	*tp,
  	xfs_inode_t	*dp,

  	struct xfs_name	*name,		/* name of entry to add */
  	uint		resblks)

  {

  	xfs_da_args_t	args;
  	int		rval;

  	int		v;		/* type-checking value */

  	if (resblks)
  		return 0;

  	ASSERT(S_ISDIR(dp->i_d.di_mode));

  	memset(&args, 0, sizeof(xfs_da_args_t));

  	args.name = name->name;
  	args.namelen = name->len;

  	args.hashval = dp->i_mount->m_dirnameops->hashname(name);

  	args.dp = dp;

  	args.whichfork = XFS_DATA_FORK;
  	args.trans = tp;

  	args.op_flags = XFS_DA_OP_JUSTCHECK | XFS_DA_OP_ADDNAME |
  							XFS_DA_OP_OKNOENT;

  	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
  		rval = xfs_dir2_sf_addname(&args);

  	else if ((rval = xfs_dir2_isblock(tp, dp, &v)))

  		return rval;

  	else if (v)

  		rval = xfs_dir2_block_addname(&args);

  	else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))

  		return rval;

  	else if (v)

  		rval = xfs_dir2_leaf_addname(&args);
  	else
  		rval = xfs_dir2_node_addname(&args);
  	return rval;
  }
  
  /*

   * Utility routines.
   */
  
  /*
   * Add a block to the directory.

   *
   * This routine is for data and free blocks, not leaf/node blocks which are
   * handled by xfs_da_grow_inode.

   */

  int

  xfs_dir2_grow_inode(

  	struct xfs_da_args	*args,
  	int			space,	/* v2 dir's space XFS_DIR2_xxx_SPACE */
  	xfs_dir2_db_t		*dbp)	/* out: block number added */

  {

  	struct xfs_inode	*dp = args->dp;
  	struct xfs_mount	*mp = dp->i_mount;
  	xfs_fileoff_t		bno;	/* directory offset of new block */
  	int			count;	/* count of filesystem blocks */
  	int			error;

  	trace_xfs_dir2_grow_inode(args, space);

  	/*
  	 * Set lowest possible block in the space requested.
  	 */
  	bno = XFS_B_TO_FSBT(mp, space * XFS_DIR2_SPACE_SIZE);
  	count = mp->m_dirblkfsbs;

  
  	error = xfs_da_grow_inode_int(args, &bno, count);
  	if (error)

  		return error;

  	*dbp = xfs_dir2_da_to_db(mp, (xfs_dablk_t)bno);

  	/*
  	 * Update file's size if this is the data space and it grew.
  	 */
  	if (space == XFS_DIR2_DATA_SPACE) {
  		xfs_fsize_t	size;		/* directory file (data) size */
  
  		size = XFS_FSB_TO_B(mp, bno + count);
  		if (size > dp->i_d.di_size) {
  			dp->i_d.di_size = size;

  			xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE);

  		}
  	}
  	return 0;
  }
  
  /*
   * See if the directory is a single-block form directory.
   */

  int

  xfs_dir2_isblock(

  	xfs_trans_t	*tp,
  	xfs_inode_t	*dp,

  	int		*vp)		/* out: 1 is block, 0 is not block */
  {
  	xfs_fileoff_t	last;		/* last file offset */

  	xfs_mount_t	*mp;
  	int		rval;

  
  	mp = dp->i_mount;

  	if ((rval = xfs_bmap_last_offset(tp, dp, &last, XFS_DATA_FORK)))

  		return rval;

  	rval = XFS_FSB_TO_B(mp, last) == mp->m_dirblksize;
  	ASSERT(rval == 0 || dp->i_d.di_size == mp->m_dirblksize);
  	*vp = rval;
  	return 0;
  }
  
  /*
   * See if the directory is a single-leaf form directory.
   */

  int

  xfs_dir2_isleaf(

  	xfs_trans_t	*tp,
  	xfs_inode_t	*dp,

  	int		*vp)		/* out: 1 is leaf, 0 is not leaf */
  {
  	xfs_fileoff_t	last;		/* last file offset */

  	xfs_mount_t	*mp;
  	int		rval;

  
  	mp = dp->i_mount;

  	if ((rval = xfs_bmap_last_offset(tp, dp, &last, XFS_DATA_FORK)))

  		return rval;

  	*vp = last == mp->m_dirleafblk + (1 << mp->m_sb.sb_dirblklog);
  	return 0;
  }
  
  /*

   * Remove the given block from the directory.
   * This routine is used for data and free blocks, leaf/node are done
   * by xfs_da_shrink_inode.
   */
  int
  xfs_dir2_shrink_inode(

  	xfs_da_args_t	*args,
  	xfs_dir2_db_t	db,
  	xfs_dabuf_t	*bp)

  {
  	xfs_fileoff_t	bno;		/* directory file offset */
  	xfs_dablk_t	da;		/* directory file offset */
  	int		done;		/* bunmap is finished */

  	xfs_inode_t	*dp;
  	int		error;
  	xfs_mount_t	*mp;
  	xfs_trans_t	*tp;

  	trace_xfs_dir2_shrink_inode(args, db);

  	dp = args->dp;
  	mp = dp->i_mount;
  	tp = args->trans;

  	da = xfs_dir2_db_to_da(mp, db);

  	/*
  	 * Unmap the fsblock(s).
  	 */
  	if ((error = xfs_bunmapi(tp, dp, da, mp->m_dirblkfsbs,
  			XFS_BMAPI_METADATA, 0, args->firstblock, args->flist,

  			&done))) {

  		/*
  		 * ENOSPC actually can happen if we're in a removename with
  		 * no space reservation, and the resulting block removal
  		 * would cause a bmap btree split or conversion from extents
  		 * to btree.  This can only happen for un-fragmented
  		 * directory blocks, since you need to be punching out
  		 * the middle of an extent.
  		 * In this case we need to leave the block in the file,
  		 * and not binval it.
  		 * So the block has to be in a consistent empty state
  		 * and appropriately logged.
  		 * We don't free up the buffer, the caller can tell it
  		 * hasn't happened since it got an error back.
  		 */
  		return error;
  	}
  	ASSERT(done);
  	/*
  	 * Invalidate the buffer from the transaction.
  	 */
  	xfs_da_binval(tp, bp);
  	/*
  	 * If it's not a data block, we're done.
  	 */
  	if (db >= XFS_DIR2_LEAF_FIRSTDB(mp))
  		return 0;
  	/*
  	 * If the block isn't the last one in the directory, we're done.
  	 */

  	if (dp->i_d.di_size > xfs_dir2_db_off_to_byte(mp, db + 1, 0))

  		return 0;
  	bno = da;
  	if ((error = xfs_bmap_last_before(tp, dp, &bno, XFS_DATA_FORK))) {
  		/*
  		 * This can't really happen unless there's kernel corruption.
  		 */
  		return error;
  	}
  	if (db == mp->m_dirdatablk)
  		ASSERT(bno == 0);
  	else
  		ASSERT(bno > 0);
  	/*
  	 * Set the size to the new last block.
  	 */
  	dp->i_d.di_size = XFS_FSB_TO_B(mp, bno);
  	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
  	return 0;
  }