path: root/fs/xfs/xfs_dir2_data.c

/*
 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
 * Copyright (c) 2013 Red Hat, 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_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_mount.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_inode.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
#include "xfs_error.h"
#include "xfs_trans.h"
#include "xfs_buf_item.h"
#include "xfs_cksum.h"

/*
 * Check the consistency of the data block.
 * The input can also be a block-format directory.
 * Return 0 is the buffer is good, otherwise an error.
 */
int
__xfs_dir3_data_check(
	struct xfs_inode	*dp,		/* incore inode pointer */
	struct xfs_buf		*bp)		/* data block's buffer */
{
	xfs_dir2_dataptr_t	addr;		/* addr for leaf lookup */
	xfs_dir2_data_free_t	*bf;		/* bestfree table */
	xfs_dir2_block_tail_t	*btp=NULL;	/* block tail */
	int			count;		/* count of entries found */
	xfs_dir2_data_hdr_t	*hdr;		/* data block header */
	xfs_dir2_data_entry_t	*dep;		/* data entry */
	xfs_dir2_data_free_t	*dfp;		/* bestfree entry */
	xfs_dir2_data_unused_t	*dup;		/* unused entry */
	char			*endp;		/* end of useful data */
	int			freeseen;	/* mask of bestfrees seen */
	xfs_dahash_t		hash;		/* hash of current name */
	int			i;		/* leaf index */
	int			lastfree;	/* last entry was unused */
	xfs_dir2_leaf_entry_t	*lep=NULL;	/* block leaf entries */
	xfs_mount_t		*mp;		/* filesystem mount point */
	char			*p;		/* current data position */
	int			stale;		/* count of stale leaves */
	struct xfs_name		name;
	const struct xfs_dir_ops *ops;

	mp = bp->b_target->bt_mount;

	/*
	 * We can be passed a null dp here from a verifier, so we need to go the
	 * hard way to get them.
	 */
	ops = xfs_dir_get_ops(mp, dp);

	hdr = bp->b_addr;
	p = (char *)ops->data_entry_p(hdr);

	switch (hdr->magic) {
	case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC):
	case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):
		btp = xfs_dir2_block_tail_p(mp, hdr);
		lep = xfs_dir2_block_leaf_p(btp);
		endp = (char *)lep;

		/*
		 * The number of leaf entries is limited by the size of the
		 * block and the amount of space used by the data entries.
		 * We don't know how much space is used by the data entries yet,
		 * so just ensure that the count falls somewhere inside the
		 * block right now.
		 */
		XFS_WANT_CORRUPTED_RETURN(be32_to_cpu(btp->count) <
			((char *)btp - p) / sizeof(struct xfs_dir2_leaf_entry));
		break;
	case cpu_to_be32(XFS_DIR3_DATA_MAGIC):
	case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
		endp = (char *)hdr + mp->m_dirblksize;
		break;
	default:
		XFS_ERROR_REPORT("Bad Magic", XFS_ERRLEVEL_LOW, mp);
		return EFSCORRUPTED;
	}

	/*
	 * Account for zero bestfree entries.
	 */
	bf = ops->data_bestfree_p(hdr);
	count = lastfree = freeseen = 0;
	if (!bf[0].length) {
		XFS_WANT_CORRUPTED_RETURN(!bf[0].offset);
		freeseen |= 1 << 0;
	}
	if (!bf[1].length) {
		XFS_WANT_CORRUPTED_RETURN(!bf[1].offset);
		freeseen |= 1 << 1;
	}
	if (!bf[2].length) {
		XFS_WANT_CORRUPTED_RETURN(!bf[2].offset);
		freeseen |= 1 << 2;
	}

	XFS_WANT_CORRUPTED_RETURN(be16_to_cpu(bf[0].length) >=
						be16_to_cpu(bf[1].length));
	XFS_WANT_CORRUPTED_RETURN(be16_to_cpu(bf[1].length) >=
						be16_to_cpu(bf[2].length));
	/*
	 * Loop over the data/unused entries.
	 */
	while (p < endp) {
		dup = (xfs_dir2_data_unused_t *)p;
		/*
		 * If it's unused, look for the space in the bestfree table.
		 * If we find it, account for that, else make sure it
		 * doesn't need to be there.
		 */
		if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
			XFS_WANT_CORRUPTED_RETURN(lastfree == 0);
			XFS_WANT_CORRUPTED_RETURN(
				be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)) ==
					       (char