path: root/fs/xfs/libxfs/xfs_dir2_data.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
 * Copyright (c) 2013 Red Hat, Inc.
 * All Rights Reserved.
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.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"
#include "xfs_log.h"

static xfs_failaddr_t xfs_dir2_data_freefind_verify(
		struct xfs_dir2_data_hdr *hdr, struct xfs_dir2_data_free *bf,
		struct xfs_dir2_data_unused *dup,
		struct xfs_dir2_data_free **bf_ent);

/*
 * Check the consistency of the data block.
 * The input can also be a block-format directory.
 * Return NULL if the buffer is good, otherwise the address of the error.
 */
xfs_failaddr_t
__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;
	struct xfs_da_geometry	*geo;

	mp = bp->b_target->bt_mount;
	geo = mp->m_dir_geo;

	/*
	 * 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);

	/*
	 * If this isn't a directory, or we don't get handed the dir ops,
	 * something is seriously wrong.  Bail out.
	 */
	if ((dp && !S_ISDIR(VFS_I(dp)->i_mode)) ||
	    ops != xfs_dir_get_ops(mp, NULL))
		return __this_address;

	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(geo, hdr);
		lep = xfs_dir2_block_leaf_p(btp);

		/*
		 * 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.
		 */
		if (be32_to_cpu(btp->count) >=
		    ((char *)btp - p) / sizeof(struct xfs_dir2_leaf_entry))
			return __this_address;
		break;
	case cpu_to_be32(XFS_DIR3_DATA_MAGIC):
	case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
		break;
	default:
		return __this_address;
	}
	endp = xfs_dir3_data_endp(geo, hdr);
	if (!endp)
		return __this_address;

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

	if (be16_to_cpu(bf[0].length) < be16_to_cpu(bf[1].length))
		return __this_address;
	if (be16_to_cpu(bf[1].length) < be16_to_cpu(bf[2].length))
		return __this_address;
	/*
	 * Loop over the data/unused entries.
	 */
	while (p <