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

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_sb.h"
#include "xfs_mount.h"
#include "xfs_ialloc.h"
#include "xfs_alloc.h"
#include "xfs_error.h"
#include "xfs_trans.h"
#include "xfs_buf_item.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_log.h"
#include "xfs_rmap_btree.h"
#include "xfs_refcount_btree.h"
#include "xfs_da_format.h"
#include "xfs_health.h"
#include "xfs_ag.h"
#include "xfs_rtbitmap.h"

/*
 * Physical superblock buffer manipulations. Shared with libxfs in userspace.
 */

/*
 * Check that all the V4 feature bits that the V5 filesystem format requires are
 * correctly set.
 */
static bool
xfs_sb_validate_v5_features(
	struct xfs_sb	*sbp)
{
	/* We must not have any unknown V4 feature bits set */
	if (sbp->sb_versionnum & ~XFS_SB_VERSION_OKBITS)
		return false;

	/*
	 * The CRC bit is considered an invalid V4 flag, so we have to add it
	 * manually to the OKBITS mask.
	 */
	if (sbp->sb_features2 & ~(XFS_SB_VERSION2_OKBITS |
				  XFS_SB_VERSION2_CRCBIT))
		return false;

	/* Now check all the required V4 feature flags are set. */

#define V5_VERS_FLAGS	(XFS_SB_VERSION_NLINKBIT	| \
			XFS_SB_VERSION_ALIGNBIT		| \
			XFS_SB_VERSION_LOGV2BIT		| \
			XFS_SB_VERSION_EXTFLGBIT	| \
			XFS_SB_VERSION_DIRV2BIT		| \
			XFS_SB_VERSION_MOREBITSBIT)

#define V5_FEAT_FLAGS	(XFS_SB_VERSION2_LAZYSBCOUNTBIT	| \
			XFS_SB_VERSION2_ATTR2BIT	| \
			XFS_SB_VERSION2_PROJID32BIT	| \
			XFS_SB_VERSION2_CRCBIT)

	if ((sbp->sb_versionnum & V5_VERS_FLAGS) != V5_VERS_FLAGS)
		return false;
	if ((sbp->sb_features2 & V5_FEAT_FLAGS) != V5_FEAT_FLAGS)
		return false;
	return true;
}

/*
 * We current support XFS v5 formats with known features and v4 superblocks with
 * at least V2 directories.
 */
bool
xfs_sb_good_version(
	struct xfs_sb	*sbp)
{
	/*
	 * All v5 filesystems are supported, but we must check that all the
	 * required v4 feature flags are enabled correctly as the code checks
	 * those flags and not for v5 support.
	 */
	if (xfs_sb_is_v5(sbp))
		return xfs_sb_validate_v5_features(sbp);

	/* versions prior to v4 are not supported */
	if (XFS_SB_VERSION_NUM(sbp) != XFS_SB_VERSION_4)
		return false;

	/* We must not have any unknown v4 feature bits set */
	if ((sbp->sb_versionnum & ~XFS_SB_VERSION_OKBITS) ||
	    ((sbp->sb_versionnum & XFS_SB_VERSION_MOREBITSBIT) &&
	     (