xfs_dir.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,224 行 · 第 1/3 页

/*
 * Copyright (c) 2000-2001 Silicon Graphics, Inc.  All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 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.
 *
 * Further, this software is distributed without any warranty that it is
 * free of the rightful claim of any third person regarding infringement
 * or the like.  Any license provided herein, whether implied or
 * otherwise, applies only to this software file.  Patent licenses, if
 * any, provided herein do not apply to combinations of this program with
 * other software, or any other product whatsoever.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write the Free Software Foundation, Inc., 59
 * Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
 * Mountain View, CA  94043, or:
 *
 * http://www.sgi.com
 *
 * For further information regarding this notice, see:
 *
 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
 */

#include "xfs.h"

#include "xfs_macros.h"
#include "xfs_types.h"
#include "xfs_inum.h"
#include "xfs_log.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_dir.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_alloc_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_alloc.h"
#include "xfs_btree.h"
#include "xfs_attr_sf.h"
#include "xfs_dir_sf.h"
#include "xfs_dir2_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_bmap.h"
#include "xfs_da_btree.h"
#include "xfs_dir_leaf.h"
#include "xfs_error.h"

/*
 * xfs_dir.c
 *
 * Provide the external interfaces to manage directories.
 */

/*========================================================================
 * Function prototypes for the kernel.
 *========================================================================*/

/*
 * Functions for the dirops interfaces.
 */
static void	xfs_dir_mount(struct xfs_mount *mp);

static int	xfs_dir_isempty(struct xfs_inode *dp);

static int	xfs_dir_init(struct xfs_trans *trans,
			     struct xfs_inode *dir,
			     struct xfs_inode *parent_dir);

static int	xfs_dir_createname(struct xfs_trans *trans,
				   struct xfs_inode *dp,
				   char *name_string,
				   int name_len,
				   xfs_ino_t inode_number,
				   xfs_fsblock_t *firstblock,
				   xfs_bmap_free_t *flist,
				   xfs_extlen_t total);

static int	xfs_dir_lookup(struct xfs_trans *tp,
			       struct xfs_inode *dp,
			       char *name_string,
			       int name_length,
			       xfs_ino_t *inode_number);

static int	xfs_dir_removename(struct xfs_trans *trans,
				   struct xfs_inode *dp,
				   char *name_string,
				   int name_length,
				   xfs_ino_t ino,
				   xfs_fsblock_t *firstblock,
				   xfs_bmap_free_t *flist,
				   xfs_extlen_t total);

static int	xfs_dir_getdents(struct xfs_trans *tp,
				 struct xfs_inode *dp,
				 struct uio *uiop,
				 int *eofp);

static int	xfs_dir_replace(struct xfs_trans *tp,
				struct xfs_inode *dp,
				char *name_string,
				int name_length,
				xfs_ino_t inode_number,
				xfs_fsblock_t *firstblock,
				xfs_bmap_free_t *flist,
				xfs_extlen_t total);

static int	xfs_dir_canenter(struct xfs_trans *tp,
				 struct xfs_inode *dp,
				 char *name_string,
				 int name_length);

static int	xfs_dir_shortform_validate_ondisk(xfs_mount_t *mp,
						  xfs_dinode_t *dip);

xfs_dirops_t xfsv1_dirops = {
	.xd_mount			= xfs_dir_mount,
	.xd_isempty			= xfs_dir_isempty,
	.xd_init			= xfs_dir_init,
	.xd_createname			= xfs_dir_createname,
	.xd_lookup			= xfs_dir_lookup,
	.xd_removename			= xfs_dir_removename,
	.xd_getdents			= xfs_dir_getdents,
	.xd_replace			= xfs_dir_replace,
	.xd_canenter			= xfs_dir_canenter,
	.xd_shortform_validate_ondisk	= xfs_dir_shortform_validate_ondisk,
	.xd_shortform_to_single		= xfs_dir_shortform_to_leaf,
};

/*
 * Internal routines when dirsize == XFS_LBSIZE(mp).
 */
STATIC int xfs_dir_leaf_lookup(xfs_da_args_t *args);
STATIC int xfs_dir_leaf_removename(xfs_da_args_t *args, int *number_entries,
						 int *total_namebytes);
STATIC int xfs_dir_leaf_getdents(xfs_trans_t *trans, xfs_inode_t *dp,
					     uio_t *uio, int *eofp,
					     xfs_dirent_t *dbp,
					     xfs_dir_put_t put);
STATIC int xfs_dir_leaf_replace(xfs_da_args_t *args);

/*
 * Internal routines when dirsize > XFS_LBSIZE(mp).
 */
STATIC int xfs_dir_node_addname(xfs_da_args_t *args);
STATIC int xfs_dir_node_lookup(xfs_da_args_t *args);
STATIC int xfs_dir_node_removename(xfs_da_args_t *args);
STATIC int xfs_dir_node_getdents(xfs_trans_t *trans, xfs_inode_t *dp,
					     uio_t *uio, int *eofp,
					     xfs_dirent_t *dbp,
					     xfs_dir_put_t put);
STATIC int xfs_dir_node_replace(xfs_da_args_t *args);

#if defined(XFS_DIR_TRACE)
ktrace_t *xfs_dir_trace_buf;
#endif


/*========================================================================
 * Overall external interface routines.
 *========================================================================*/

xfs_dahash_t	xfs_dir_hash_dot, xfs_dir_hash_dotdot;

/*
 * One-time startup routine called from xfs_init().
 */
void
xfs_dir_startup(void)
{
	xfs_dir_hash_dot = xfs_da_hashname(".", 1);
	xfs_dir_hash_dotdot = xfs_da_hashname("..", 2);
}

/*
 * Initialize directory-related fields in the mount structure.
 */
static void
xfs_dir_mount(xfs_mount_t *mp)
{
	uint shortcount, leafcount, count;

	mp->m_dirversion = 1;
	shortcount = (mp->m_attroffset - (uint)sizeof(xfs_dir_sf_hdr_t)) /
		     (uint)sizeof(xfs_dir_sf_entry_t);
	leafcount = (XFS_LBSIZE(mp) - (uint)sizeof(xfs_dir_leaf_hdr_t)) /
		    ((uint)sizeof(xfs_dir_leaf_entry_t) +
		     (uint)sizeof(xfs_dir_leaf_name_t));
	count = shortcount > leafcount ? shortcount : leafcount;
	mp->m_dircook_elog = xfs_da_log2_roundup(count + 1);
	ASSERT(mp->m_dircook_elog <= mp->m_sb.sb_blocklog);
	mp->m_dir_node_ents = mp->m_attr_node_ents =
		(XFS_LBSIZE(mp) - (uint)sizeof(xfs_da_node_hdr_t)) /
		(uint)sizeof(xfs_da_node_entry_t);
	mp->m_dir_magicpct = (XFS_LBSIZE(mp) * 37) / 100;
	mp->m_dirblksize = mp->m_sb.sb_blocksize;
	mp->m_dirblkfsbs = 1;
}

/*
 * Return 1 if directory contains only "." and "..".
 */
static int
xfs_dir_isempty(xfs_inode_t *dp)
{
	xfs_dir_sf_hdr_t *hdr;

	ASSERT((dp->i_d.di_mode & S_IFMT) == S_IFDIR);
	if (dp->i_d.di_size == 0)
		return(1);
	if (dp->i_d.di_size > XFS_IFORK_DSIZE(dp))
		return(0);
	hdr = (xfs_dir_sf_hdr_t *)dp->i_df.if_u1.if_data;
	return(hdr->count == 0);
}

/*
 * Initialize a directory with its "." and ".." entries.
 */
static int
xfs_dir_init(xfs_trans_t *trans, xfs_inode_t *dir, xfs_inode_t *parent_dir)
{
	xfs_da_args_t args;
	int error;

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

	ASSERT((dir->i_d.di_mode & S_IFMT) == S_IFDIR);
	if ((error = xfs_dir_ino_validate(trans->t_mountp, parent_dir->i_ino)))
		return error;

	return(xfs_dir_shortform_create(&args, parent_dir->i_ino));
}

/*
 * Generic handler routine to add a name to a directory.
 * Transitions directory from shortform to Btree as necessary.
 */
static int							/* error */
xfs_dir_createname(xfs_trans_t *trans, xfs_inode_t *dp, char *name,
		   int namelen, xfs_ino_t inum, xfs_fsblock_t *firstblock,
		   xfs_bmap_free_t *flist, xfs_extlen_t total)
{
	xfs_da_args_t args;
	int retval, newsize, done;

	ASSERT((dp->i_d.di_mode & S_IFMT) == S_IFDIR);

	if ((retval = xfs_dir_ino_validate(trans->t_mountp, inum)))
		return (retval);

	XFS_STATS_INC(xs_dir_create);
	/*
	 * Fill in the arg structure for this request.
	 */
	args.name = name;
	args.namelen = namelen;
	args.hashval = xfs_da_hashname(name, namelen);
	args.inumber = inum;
	args.dp = dp;
	args.firstblock = firstblock;
	args.flist = flist;
	args.total = total;
	args.whichfork = XFS_DATA_FORK;
	args.trans = trans;
	args.justcheck = 0;
	args.addname = args.oknoent = 1;

	/*
	 * Decide on what work routines to call based on the inode size.
	 */
	done = 0;
	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
		newsize = XFS_DIR_SF_ENTSIZE_BYNAME(args.namelen);
		if ((dp->i_d.di_size + newsize) <= XFS_IFORK_DSIZE(dp)) {
			retval = xfs_dir_shortform_addname(&args);
			done = 1;
		} else {
			if (total == 0)
				return XFS_ERROR(ENOSPC);
			retval = xfs_dir_shortform_to_leaf(&args);
			done = retval != 0;
		}
	}
	if (!done && xfs_bmap_one_block(dp, XFS_DATA_FORK)) {
		retval = xfs_dir_leaf_addname(&args);
		done = retval != ENOSPC;
		if (!done) {
			if (total == 0)
				return XFS_ERROR(ENOSPC);
			retval = xfs_dir_leaf_to_node(&args);
			done = retval != 0;
		}
	}
	if (!done) {
		retval = xfs_dir_node_addname(&args);
	}
	return(retval);
}

/*
 * Generic handler routine to check if a name can be added to a directory,
 * without adding any blocks to the directory.
 */
static int							/* error */
xfs_dir_canenter(xfs_trans_t *trans, xfs_inode_t *dp, char *name, int namelen)
{
	xfs_da_args_t args;
	int retval, newsize;

	ASSERT((dp->i_d.di_mode & S_IFMT) == S_IFDIR);
	/*
	 * Fill in the arg structure for this request.
	 */
	args.name = name;
	args.namelen = namelen;
	args.hashval = xfs_da_hashname(name, namelen);
	args.inumber = 0;
	args.dp = dp;
	args.firstblock = NULL;
	args.flist = NULL;
	args.total = 0;
	args.whichfork = XFS_DATA_FORK;
	args.trans = trans;
	args.justcheck = args.addname = args.oknoent = 1;

	/*
	 * Decide on what work routines to call based on the inode size.
	 */
	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
		newsize = XFS_DIR_SF_ENTSIZE_BYNAME(args.namelen);
		if ((dp->i_d.di_size + newsize) <= XFS_IFORK_DSIZE(dp))
			retval = 0;
		else
			retval = XFS_ERROR(ENOSPC);
	} else if (xfs_bmap_one_block(dp, XFS_DATA_FORK)) {
		retval = xfs_dir_leaf_addname(&args);
	} else {
		retval = xfs_dir_node_addname(&args);
	}
	return(retval);
}

/*
 * Generic handler routine to remove a name from a directory.
 * Transitions directory from Btree to shortform as necessary.
 */
static int							/* error */
xfs_dir_removename(xfs_trans_t *trans, xfs_inode_t *dp, char *name,
		   int namelen, xfs_ino_t ino, xfs_fsblock_t *firstblock,
		   xfs_bmap_free_t *flist, xfs_extlen_t total)
{
	xfs_da_args_t args;
	int count, totallen, newsize, retval;

	ASSERT((dp->i_d.di_mode & S_IFMT) == S_IFDIR);
	XFS_STATS_INC(xs_dir_remove);
	/*
	 * Fill in the arg structure for this request.
	 */
	args.name = name;
	args.namelen = namelen;
	args.hashval = xfs_da_hashname(name, namelen);
	args.inumber = ino;
	args.dp = dp;
	args.firstblock = firstblock;
	args.flist = flist;
	args.total = total;
	args.whichfork = XFS_DATA_FORK;
	args.trans = trans;
	args.justcheck = args.addname = args.oknoent = 0;

	/*
	 * Decide on what work routines to call based on the inode size.
	 */
	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
		retval = xfs_dir_shortform_removename(&args);
	} else if (xfs_bmap_one_block(dp, XFS_DATA_FORK)) {
		retval = xfs_dir_leaf_removename(&args, &count, &totallen);
		if (retval == 0) {
			newsize = XFS_DIR_SF_ALLFIT(count, totallen);
			if (newsize <= XFS_IFORK_DSIZE(dp)) {
				retval = xfs_dir_leaf_to_shortform(&args);
			}
		}
	} else {
		retval = xfs_dir_node_removename(&args);
	}
	return(retval);
}

static int							/* error */
xfs_dir_lookup(xfs_trans_t *trans, xfs_inode_t *dp, char *name, int namelen,
				   xfs_ino_t *inum)
{