/*
   * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
   */

  #include <linux/string.h>
  #include <linux/errno.h>
  #include <linux/fs.h>

  #include "reiserfs.h"

  #include <linux/stat.h>

  #include <linux/buffer_head.h>

  #include <linux/slab.h>

  #include <linux/uaccess.h>

  extern const struct reiserfs_key MIN_KEY;

  static int reiserfs_readdir(struct file *, struct dir_context *);

  static int reiserfs_dir_fsync(struct file *filp, loff_t start, loff_t end,
  			      int datasync);

  const struct file_operations reiserfs_dir_operations = {

  	.llseek = generic_file_llseek,

  	.read = generic_read_dir,

  	.iterate_shared = reiserfs_readdir,

  	.fsync = reiserfs_dir_fsync,

  	.unlocked_ioctl = reiserfs_ioctl,

  #ifdef CONFIG_COMPAT
  	.compat_ioctl = reiserfs_compat_ioctl,
  #endif

  };

  static int reiserfs_dir_fsync(struct file *filp, loff_t start, loff_t end,
  			      int datasync)

  {

  	struct inode *inode = filp->f_mapping->host;

  	int err;

  	err = file_write_and_wait_range(filp, start, end);

  	if (err)
  		return err;

  	inode_lock(inode);

  	reiserfs_write_lock(inode->i_sb);
  	err = reiserfs_commit_for_inode(inode);
  	reiserfs_write_unlock(inode->i_sb);

  	inode_unlock(inode);

  	if (err < 0)
  		return err;
  	return 0;

  }

  #define store_ih(where,what) copy_item_head (where, what)

  static inline bool is_privroot_deh(struct inode *dir, struct reiserfs_de_head *deh)

  {

  	struct dentry *privroot = REISERFS_SB(dir->i_sb)->priv_root;

  	return (d_really_is_positive(privroot) &&
  	        deh->deh_objectid == INODE_PKEY(d_inode(privroot))->k_objectid);

  }

  int reiserfs_readdir_inode(struct inode *inode, struct dir_context *ctx)

  {

  
  	/* key of current position in the directory (key of directory entry) */
  	struct cpu_key pos_key;

  	INITIALIZE_PATH(path_to_entry);
  	struct buffer_head *bh;
  	int item_num, entry_num;
  	const struct reiserfs_key *rkey;
  	struct item_head *ih, tmp_ih;
  	int search_res;
  	char *local_buf;
  	loff_t next_pos;
  	char small_buf[32];	/* avoid kmalloc if we can */
  	struct reiserfs_dir_entry de;
  	int ret = 0;

  	int depth;

  
  	reiserfs_write_lock(inode->i_sb);
  
  	reiserfs_check_lock_depth(inode->i_sb, "readdir");

  	/*
  	 * form key for search the next directory entry using
  	 * f_pos field of file structure
  	 */

  	make_cpu_key(&pos_key, inode, ctx->pos ?: DOT_OFFSET, TYPE_DIRENTRY, 3);

  	next_pos = cpu_key_k_offset(&pos_key);

  	path_to_entry.reada = PATH_READA;
  	while (1) {

  research:

  		/*
  		 * search the directory item, containing entry with
  		 * specified key
  		 */

  		search_res =
  		    search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
  					&de);
  		if (search_res == IO_ERROR) {

  			/*
  			 * FIXME: we could just skip part of directory
  			 * which could not be read
  			 */

  			ret = -EIO;

  			goto out;

  		}

  		entry_num = de.de_entry_num;
  		bh = de.de_bh;
  		item_num = de.de_item_num;
  		ih = de.de_ih;
  		store_ih(&tmp_ih, ih);
  
  		/* we must have found item, that is item of this directory, */

  		RFALSE(COMP_SHORT_KEYS(&ih->ih_key, &pos_key),

  		       "vs-9000: found item %h does not match to dir we readdir %K",
  		       ih, &pos_key);
  		RFALSE(item_num > B_NR_ITEMS(bh) - 1,
  		       "vs-9005 item_num == %d, item amount == %d",
  		       item_num, B_NR_ITEMS(bh));

  		/*
  		 * and entry must be not more than number of entries
  		 * in the item
  		 */

  		RFALSE(ih_entry_count(ih) < entry_num,

  		       "vs-9010: entry number is too big %d (%d)",

  		       entry_num, ih_entry_count(ih));

  		/*
  		 * go through all entries in the directory item beginning
  		 * from the entry, that has been found
  		 */

  		if (search_res == POSITION_FOUND

  		    || entry_num < ih_entry_count(ih)) {

  			struct reiserfs_de_head *deh =
  			    B_I_DEH(bh, ih) + entry_num;

  			for (; entry_num < ih_entry_count(ih);

  			     entry_num++, deh++) {
  				int d_reclen;
  				char *d_name;

  				ino_t d_ino;

  				loff_t cur_pos = deh_offset(deh);

  				/* it is hidden entry */

  				if (!de_visible(deh))

  					continue;
  				d_reclen = entry_length(bh, ih, entry_num);
  				d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);

  
  				if (d_reclen <= 0 ||
  				    d_name + d_reclen > bh->b_data + bh->b_size) {

  					/*
  					 * There is corrupted data in entry,
  					 * We'd better stop here
  					 */

  					pathrelse(&path_to_entry);
  					ret = -EIO;
  					goto out;
  				}

  				if (!d_name[d_reclen - 1])
  					d_reclen = strlen(d_name);

  				/* too big to send back to VFS */

  				if (d_reclen >
  				    REISERFS_MAX_NAME(inode->i_sb->
  						      s_blocksize)) {

  					continue;
  				}
  
  				/* Ignore the .reiserfs_priv entry */

  				if (is_privroot_deh(inode, deh))

  					continue;

  				ctx->pos = deh_offset(deh);

  				d_ino = deh_objectid(deh);
  				if (d_reclen <= 32) {
  					local_buf = small_buf;
  				} else {

  					local_buf = kmalloc(d_reclen,
  							    GFP_NOFS);

  					if (!local_buf) {
  						pathrelse(&path_to_entry);
  						ret = -ENOMEM;
  						goto out;
  					}
  					if (item_moved(&tmp_ih, &path_to_entry)) {

  						kfree(local_buf);

  						goto research;
  					}
  				}

  
  				/*
  				 * Note, that we copy name to user space via
  				 * temporary buffer (local_buf) because
  				 * filldir will block if user space buffer is
  				 * swapped out. At that time entry can move to
  				 * somewhere else
  				 */

  				memcpy(local_buf, d_name, d_reclen);

  
  				/*
  				 * Since filldir might sleep, we can release
  				 * the write lock here for other waiters
  				 */

  				depth = reiserfs_write_unlock_nested(inode->i_sb);

  				if (!dir_emit
  				    (ctx, local_buf, d_reclen, d_ino,
  				     DT_UNKNOWN)) {

  					reiserfs_write_lock_nested(inode->i_sb, depth);

  					if (local_buf != small_buf) {

  						kfree(local_buf);

  					}
  					goto end;
  				}

  				reiserfs_write_lock_nested(inode->i_sb, depth);

  				if (local_buf != small_buf) {

  					kfree(local_buf);

  				}

  
  				/* deh_offset(deh) may be invalid now. */
  				next_pos = cur_pos + 1;

  
  				if (item_moved(&tmp_ih, &path_to_entry)) {

  					set_cpu_key_k_offset(&pos_key,
  							     next_pos);

  					goto research;
  				}
  			}	/* for */

  		}

  		/* end of directory has been reached */

  		if (item_num != B_NR_ITEMS(bh) - 1)

  			goto end;

  		/*
  		 * item we went through is last item of node. Using right
  		 * delimiting key check is it directory end
  		 */

  		rkey = get_rkey(&path_to_entry, inode->i_sb);
  		if (!comp_le_keys(rkey, &MIN_KEY)) {

  			/*
  			 * set pos_key to key, that is the smallest and greater
  			 * that key of the last entry in the item
  			 */

  			set_cpu_key_k_offset(&pos_key, next_pos);
  			continue;
  		}

  		/* end of directory has been reached */

  		if (COMP_SHORT_KEYS(rkey, &pos_key)) {

  			goto end;

  		}

  
  		/* directory continues in the right neighboring block */
  		set_cpu_key_k_offset(&pos_key,
  				     le_key_k_offset(KEY_FORMAT_3_5, rkey));
  
  	}			/* while */

  end:

  	ctx->pos = next_pos;

  	pathrelse(&path_to_entry);
  	reiserfs_check_path(&path_to_entry);

  out:

  	reiserfs_write_unlock(inode->i_sb);
  	return ret;

  }

  static int reiserfs_readdir(struct file *file, struct dir_context *ctx)

  {

  	return reiserfs_readdir_inode(file_inode(file), ctx);

  }

  /*
   * compose directory item containing "." and ".." entries (entries are
   * not aligned to 4 byte boundary)
   */

  void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
  			    __le32 par_dirid, __le32 par_objid)

  {

  	struct reiserfs_de_head *dot, *dotdot;

  
  	memset(body, 0, EMPTY_DIR_SIZE_V1);

  	dot = (struct reiserfs_de_head *)body;
  	dotdot = dot + 1;

  
  	/* direntry header of "." */

  	put_deh_offset(dot, DOT_OFFSET);

  	/* these two are from make_le_item_head, and are are LE */

  	dot->deh_dir_id = dirid;
  	dot->deh_objectid = objid;
  	dot->deh_state = 0;	/* Endian safe if 0 */
  	put_deh_location(dot, EMPTY_DIR_SIZE_V1 - strlen("."));
  	mark_de_visible(dot);

  
  	/* direntry header of ".." */

  	put_deh_offset(dotdot, DOT_DOT_OFFSET);

  	/* key of ".." for the root directory */
  	/* these two are from the inode, and are are LE */

  	dotdot->deh_dir_id = par_dirid;
  	dotdot->deh_objectid = par_objid;
  	dotdot->deh_state = 0;	/* Endian safe if 0 */
  	put_deh_location(dotdot, deh_location(dot) - strlen(".."));
  	mark_de_visible(dotdot);

  
  	/* copy ".." and "." */

  	memcpy(body + deh_location(dot), ".", 1);
  	memcpy(body + deh_location(dotdot), "..", 2);

  }
  
  /* compose directory item containing "." and ".." entries */

  void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
  			 __le32 par_dirid, __le32 par_objid)

  {

  	struct reiserfs_de_head *dot, *dotdot;

  
  	memset(body, 0, EMPTY_DIR_SIZE);

  	dot = (struct reiserfs_de_head *)body;
  	dotdot = dot + 1;

  
  	/* direntry header of "." */

  	put_deh_offset(dot, DOT_OFFSET);

  	/* these two are from make_le_item_head, and are are LE */

  	dot->deh_dir_id = dirid;
  	dot->deh_objectid = objid;
  	dot->deh_state = 0;	/* Endian safe if 0 */
  	put_deh_location(dot, EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
  	mark_de_visible(dot);

  
  	/* direntry header of ".." */

  	put_deh_offset(dotdot, DOT_DOT_OFFSET);

  	/* key of ".." for the root directory */
  	/* these two are from the inode, and are are LE */

  	dotdot->deh_dir_id = par_dirid;
  	dotdot->deh_objectid = par_objid;
  	dotdot->deh_state = 0;	/* Endian safe if 0 */
  	put_deh_location(dotdot, deh_location(dot) - ROUND_UP(strlen("..")));
  	mark_de_visible(dotdot);

  
  	/* copy ".." and "." */

  	memcpy(body + deh_location(dot), ".", 1);
  	memcpy(body + deh_location(dotdot), "..", 2);

  }