Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1375 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
new file mode 100644
index 0000000000..6264daaab3
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -0,0 +1,1375 @@
+// 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"
+
+/*
+ * 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) &&
+	     (sbp->sb_features2 & ~XFS_SB_VERSION2_OKBITS)))
+		return false;
+
+	/* V4 filesystems need v2 directories and unwritten extents */
+	if (!(sbp->sb_versionnum & XFS_SB_VERSION_DIRV2BIT))
+		return false;
+	if (!(sbp->sb_versionnum & XFS_SB_VERSION_EXTFLGBIT))
+		return false;
+
+	/* It's a supported v4 filesystem */
+	return true;
+}
+
+uint64_t
+xfs_sb_version_to_features(
+	struct xfs_sb	*sbp)
+{
+	uint64_t	features = 0;
+
+	/* optional V4 features */
+	if (sbp->sb_rblocks > 0)
+		features |= XFS_FEAT_REALTIME;
+	if (sbp->sb_versionnum & XFS_SB_VERSION_NLINKBIT)
+		features |= XFS_FEAT_NLINK;
+	if (sbp->sb_versionnum & XFS_SB_VERSION_ATTRBIT)
+		features |= XFS_FEAT_ATTR;
+	if (sbp->sb_versionnum & XFS_SB_VERSION_QUOTABIT)
+		features |= XFS_FEAT_QUOTA;
+	if (sbp->sb_versionnum & XFS_SB_VERSION_ALIGNBIT)
+		features |= XFS_FEAT_ALIGN;
+	if (sbp->sb_versionnum & XFS_SB_VERSION_LOGV2BIT)
+		features |= XFS_FEAT_LOGV2;
+	if (sbp->sb_versionnum & XFS_SB_VERSION_DALIGNBIT)
+		features |= XFS_FEAT_DALIGN;
+	if (sbp->sb_versionnum & XFS_SB_VERSION_EXTFLGBIT)
+		features |= XFS_FEAT_EXTFLG;
+	if (sbp->sb_versionnum & XFS_SB_VERSION_SECTORBIT)
+		features |= XFS_FEAT_SECTOR;
+	if (sbp->sb_versionnum & XFS_SB_VERSION_BORGBIT)
+		features |= XFS_FEAT_ASCIICI;
+	if (sbp->sb_versionnum & XFS_SB_VERSION_MOREBITSBIT) {
+		if (sbp->sb_features2 & XFS_SB_VERSION2_LAZYSBCOUNTBIT)
+			features |= XFS_FEAT_LAZYSBCOUNT;
+		if (sbp->sb_features2 & XFS_SB_VERSION2_ATTR2BIT)
+			features |= XFS_FEAT_ATTR2;
+		if (sbp->sb_features2 & XFS_SB_VERSION2_PROJID32BIT)
+			features |= XFS_FEAT_PROJID32;
+		if (sbp->sb_features2 & XFS_SB_VERSION2_FTYPE)
+			features |= XFS_FEAT_FTYPE;
+	}
+
+	if (!xfs_sb_is_v5(sbp))
+		return features;
+
+	/* Always on V5 features */
+	features |= XFS_FEAT_ALIGN | XFS_FEAT_LOGV2 | XFS_FEAT_EXTFLG |
+		    XFS_FEAT_LAZYSBCOUNT | XFS_FEAT_ATTR2 | XFS_FEAT_PROJID32 |
+		    XFS_FEAT_V3INODES | XFS_FEAT_CRC | XFS_FEAT_PQUOTINO;
+
+	/* Optional V5 features */
+	if (sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_FINOBT)
+		features |= XFS_FEAT_FINOBT;
+	if (sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_RMAPBT)
+		features |= XFS_FEAT_RMAPBT;
+	if (sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_REFLINK)
+		features |= XFS_FEAT_REFLINK;
+	if (sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_INOBTCNT)
+		features |= XFS_FEAT_INOBTCNT;
+	if (sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_FTYPE)
+		features |= XFS_FEAT_FTYPE;
+	if (sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_SPINODES)
+		features |= XFS_FEAT_SPINODES;
+	if (sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_META_UUID)
+		features |= XFS_FEAT_META_UUID;
+	if (sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_BIGTIME)
+		features |= XFS_FEAT_BIGTIME;
+	if (sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR)
+		features |= XFS_FEAT_NEEDSREPAIR;
+	if (sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_NREXT64)
+		features |= XFS_FEAT_NREXT64;
+
+	return features;
+}
+
+/* Check all the superblock fields we care about when reading one in. */
+STATIC int
+xfs_validate_sb_read(
+	struct xfs_mount	*mp,
+	struct xfs_sb		*sbp)
+{
+	if (!xfs_sb_is_v5(sbp))
+		return 0;
+
+	/*
+	 * Version 5 superblock feature mask validation. Reject combinations
+	 * the kernel cannot support up front before checking anything else.
+	 */
+	if (xfs_sb_has_compat_feature(sbp, XFS_SB_FEAT_COMPAT_UNKNOWN)) {
+		xfs_warn(mp,
+"Superblock has unknown compatible features (0x%x) enabled.",
+			(sbp->sb_features_compat & XFS_SB_FEAT_COMPAT_UNKNOWN));
+		xfs_warn(mp,
+"Using a more recent kernel is recommended.");
+	}
+
+	if (xfs_sb_has_ro_compat_feature(sbp, XFS_SB_FEAT_RO_COMPAT_UNKNOWN)) {
+		xfs_alert(mp,
+"Superblock has unknown read-only compatible features (0x%x) enabled.",
+			(sbp->sb_features_ro_compat &
+					XFS_SB_FEAT_RO_COMPAT_UNKNOWN));
+		if (!xfs_is_readonly(mp)) {
+			xfs_warn(mp,
+"Attempted to mount read-only compatible filesystem read-write.");
+			xfs_warn(mp,
+"Filesystem can only be safely mounted read only.");
+
+			return -EINVAL;
+		}
+	}
+	if (xfs_sb_has_incompat_feature(sbp, XFS_SB_FEAT_INCOMPAT_UNKNOWN)) {
+		xfs_warn(mp,
+"Superblock has unknown incompatible features (0x%x) enabled.",
+			(sbp->sb_features_incompat &
+					XFS_SB_FEAT_INCOMPAT_UNKNOWN));
+		xfs_warn(mp,
+"Filesystem cannot be safely mounted by this kernel.");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/* Check all the superblock fields we care about when writing one out. */
+STATIC int
+xfs_validate_sb_write(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp,
+	struct xfs_sb		*sbp)
+{
+	/*
+	 * Carry out additional sb summary counter sanity checks when we write
+	 * the superblock.  We skip this in the read validator because there
+	 * could be newer superblocks in the log and if the values are garbage
+	 * even after replay we'll recalculate them at the end of log mount.
+	 *
+	 * mkfs has traditionally written zeroed counters to inprogress and
+	 * secondary superblocks, so allow this usage to continue because
+	 * we never read counters from such superblocks.
+	 */
+	if (xfs_buf_daddr(bp) == XFS_SB_DADDR && !sbp->sb_inprogress &&
+	    (sbp->sb_fdblocks > sbp->sb_dblocks ||
+	     !xfs_verify_icount(mp, sbp->sb_icount) ||
+	     sbp->sb_ifree > sbp->sb_icount)) {
+		xfs_warn(mp, "SB summary counter sanity check failed");
+		return -EFSCORRUPTED;
+	}
+
+	if (!xfs_sb_is_v5(sbp))
+		return 0;
+
+	/*
+	 * Version 5 superblock feature mask validation. Reject combinations
+	 * the kernel cannot support since we checked for unsupported bits in
+	 * the read verifier, which means that memory is corrupt.
+	 */
+	if (xfs_sb_has_compat_feature(sbp, XFS_SB_FEAT_COMPAT_UNKNOWN)) {
+		xfs_warn(mp,
+"Corruption detected in superblock compatible features (0x%x)!",
+			(sbp->sb_features_compat & XFS_SB_FEAT_COMPAT_UNKNOWN));
+		return -EFSCORRUPTED;
+	}
+
+	if (!xfs_is_readonly(mp) &&
+	    xfs_sb_has_ro_compat_feature(sbp, XFS_SB_FEAT_RO_COMPAT_UNKNOWN)) {
+		xfs_alert(mp,
+"Corruption detected in superblock read-only compatible features (0x%x)!",
+			(sbp->sb_features_ro_compat &
+					XFS_SB_FEAT_RO_COMPAT_UNKNOWN));
+		return -EFSCORRUPTED;
+	}
+	if (xfs_sb_has_incompat_feature(sbp, XFS_SB_FEAT_INCOMPAT_UNKNOWN)) {
+		xfs_warn(mp,
+"Corruption detected in superblock incompatible features (0x%x)!",
+			(sbp->sb_features_incompat &
+					XFS_SB_FEAT_INCOMPAT_UNKNOWN));
+		return -EFSCORRUPTED;
+	}
+	if (xfs_sb_has_incompat_log_feature(sbp,
+			XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN)) {
+		xfs_warn(mp,
+"Corruption detected in superblock incompatible log features (0x%x)!",
+			(sbp->sb_features_log_incompat &
+					XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN));
+		return -EFSCORRUPTED;
+	}
+
+	/*
+	 * We can't read verify the sb LSN because the read verifier is called
+	 * before the log is allocated and processed. We know the log is set up
+	 * before write verifier calls, so check it here.
+	 */
+	if (!xfs_log_check_lsn(mp, sbp->sb_lsn))
+		return -EFSCORRUPTED;
+
+	return 0;
+}
+
+/* Check the validity of the SB. */
+STATIC int
+xfs_validate_sb_common(
+	struct xfs_mount	*mp,
+	struct xfs_buf		*bp,
+	struct xfs_sb		*sbp)
+{
+	struct xfs_dsb		*dsb = bp->b_addr;
+	uint32_t		agcount = 0;
+	uint32_t		rem;
+	bool			has_dalign;
+
+	if (!xfs_verify_magic(bp, dsb->sb_magicnum)) {
+		xfs_warn(mp,
+"Superblock has bad magic number 0x%x. Not an XFS filesystem?",
+			be32_to_cpu(dsb->sb_magicnum));
+		return -EWRONGFS;
+	}
+
+	if (!xfs_sb_good_version(sbp)) {
+		xfs_warn(mp,
+"Superblock has unknown features enabled or corrupted feature masks.");
+		return -EWRONGFS;
+	}
+
+	/*
+	 * Validate feature flags and state
+	 */
+	if (xfs_sb_is_v5(sbp)) {
+		if (sbp->sb_blocksize < XFS_MIN_CRC_BLOCKSIZE) {
+			xfs_notice(mp,
+"Block size (%u bytes) too small for Version 5 superblock (minimum %d bytes)",
+				sbp->sb_blocksize, XFS_MIN_CRC_BLOCKSIZE);
+			return -EFSCORRUPTED;
+		}
+
+		/* V5 has a separate project quota inode */
+		if (sbp->sb_qflags & (XFS_OQUOTA_ENFD | XFS_OQUOTA_CHKD)) {
+			xfs_notice(mp,
+			   "Version 5 of Super block has XFS_OQUOTA bits.");
+			return -EFSCORRUPTED;
+		}
+
+		/*
+		 * Full inode chunks must be aligned to inode chunk size when
+		 * sparse inodes are enabled to support the sparse chunk
+		 * allocation algorithm and prevent overlapping inode records.
+		 */
+		if (sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_SPINODES) {
+			uint32_t	align;
+
+			align = XFS_INODES_PER_CHUNK * sbp->sb_inodesize
+					>> sbp->sb_blocklog;
+			if (sbp->sb_inoalignmt != align) {
+				xfs_warn(mp,
+"Inode block alignment (%u) must match chunk size (%u) for sparse inodes.",
+					 sbp->sb_inoalignmt, align);
+				return -EINVAL;
+			}
+		}
+	} else if (sbp->sb_qflags & (XFS_PQUOTA_ENFD | XFS_GQUOTA_ENFD |
+				XFS_PQUOTA_CHKD | XFS_GQUOTA_CHKD)) {
+			xfs_notice(mp,
+"Superblock earlier than Version 5 has XFS_{P|G}QUOTA_{ENFD|CHKD} bits.");
+			return -EFSCORRUPTED;
+	}
+
+	if (unlikely(
+	    sbp->sb_logstart == 0 && mp->m_logdev_targp == mp->m_ddev_targp)) {
+		xfs_warn(mp,
+		"filesystem is marked as having an external log; "
+		"specify logdev on the mount command line.");
+		return -EINVAL;
+	}
+
+	if (unlikely(
+	    sbp->sb_logstart != 0 && mp->m_logdev_targp != mp->m_ddev_targp)) {
+		xfs_warn(mp,
+		"filesystem is marked as having an internal log; "
+		"do not specify logdev on the mount command line.");
+		return -EINVAL;
+	}
+
+	/* Compute agcount for this number of dblocks and agblocks */
+	if (sbp->sb_agblocks) {
+		agcount = div_u64_rem(sbp->sb_dblocks, sbp->sb_agblocks, &rem);
+		if (rem)
+			agcount++;
+	}
+
+	/*
+	 * More sanity checking.  Most of these were stolen directly from
+	 * xfs_repair.
+	 */
+	if (unlikely(
+	    sbp->sb_agcount <= 0					||
+	    sbp->sb_sectsize < XFS_MIN_SECTORSIZE			||
+	    sbp->sb_sectsize > XFS_MAX_SECTORSIZE			||
+	    sbp->sb_sectlog < XFS_MIN_SECTORSIZE_LOG			||
+	    sbp->sb_sectlog > XFS_MAX_SECTORSIZE_LOG			||
+	    sbp->sb_sectsize != (1 << sbp->sb_sectlog)			||
+	    sbp->sb_blocksize < XFS_MIN_BLOCKSIZE			||
+	    sbp->sb_blocksize > XFS_MAX_BLOCKSIZE			||
+	    sbp->sb_blocklog < XFS_MIN_BLOCKSIZE_LOG			||
+	    sbp->sb_blocklog > XFS_MAX_BLOCKSIZE_LOG			||
+	    sbp->sb_blocksize != (1 << sbp->sb_blocklog)		||
+	    sbp->sb_dirblklog + sbp->sb_blocklog > XFS_MAX_BLOCKSIZE_LOG ||
+	    sbp->sb_inodesize < XFS_DINODE_MIN_SIZE			||
+	    sbp->sb_inodesize > XFS_DINODE_MAX_SIZE			||
+	    sbp->sb_inodelog < XFS_DINODE_MIN_LOG			||
+	    sbp->sb_inodelog > XFS_DINODE_MAX_LOG			||
+	    sbp->sb_inodesize != (1 << sbp->sb_inodelog)		||
+	    sbp->sb_inopblock != howmany(sbp->sb_blocksize,sbp->sb_inodesize) ||
+	    XFS_FSB_TO_B(mp, sbp->sb_agblocks) < XFS_MIN_AG_BYTES	||
+	    XFS_FSB_TO_B(mp, sbp->sb_agblocks) > XFS_MAX_AG_BYTES	||
+	    sbp->sb_agblklog != xfs_highbit32(sbp->sb_agblocks - 1) + 1	||
+	    agcount == 0 || agcount != sbp->sb_agcount			||
+	    (sbp->sb_blocklog - sbp->sb_inodelog != sbp->sb_inopblog)	||
+	    (sbp->sb_rextsize * sbp->sb_blocksize > XFS_MAX_RTEXTSIZE)	||
+	    (sbp->sb_rextsize * sbp->sb_blocksize < XFS_MIN_RTEXTSIZE)	||
+	    (sbp->sb_imax_pct > 100 /* zero sb_imax_pct is valid */)	||
+	    sbp->sb_dblocks == 0					||
+	    sbp->sb_dblocks > XFS_MAX_DBLOCKS(sbp)			||
+	    sbp->sb_dblocks < XFS_MIN_DBLOCKS(sbp)			||
+	    sbp->sb_shared_vn != 0)) {
+		xfs_notice(mp, "SB sanity check failed");
+		return -EFSCORRUPTED;
+	}
+
+	/*
+	 * Logs that are too large are not supported at all. Reject them
+	 * outright. Logs that are too small are tolerated on v4 filesystems,
+	 * but we can only check that when mounting the log. Hence we skip
+	 * those checks here.
+	 */
+	if (sbp->sb_logblocks > XFS_MAX_LOG_BLOCKS) {
+		xfs_notice(mp,
+		"Log size 0x%x blocks too large, maximum size is 0x%llx blocks",
+			 sbp->sb_logblocks, XFS_MAX_LOG_BLOCKS);
+		return -EFSCORRUPTED;
+	}
+
+	if (XFS_FSB_TO_B(mp, sbp->sb_logblocks) > XFS_MAX_LOG_BYTES) {
+		xfs_warn(mp,
+		"log size 0x%llx bytes too large, maximum size is 0x%llx bytes",
+			 XFS_FSB_TO_B(mp, sbp->sb_logblocks),
+			 XFS_MAX_LOG_BYTES);
+		return -EFSCORRUPTED;
+	}
+
+	/*
+	 * Do not allow filesystems with corrupted log sector or stripe units to
+	 * be mounted. We cannot safely size the iclogs or write to the log if
+	 * the log stripe unit is not valid.
+	 */
+	if (sbp->sb_versionnum & XFS_SB_VERSION_SECTORBIT) {
+		if (sbp->sb_logsectsize != (1U << sbp->sb_logsectlog)) {
+			xfs_notice(mp,
+			"log sector size in bytes/log2 (0x%x/0x%x) must match",
+				sbp->sb_logsectsize, 1U << sbp->sb_logsectlog);
+			return -EFSCORRUPTED;
+		}
+	} else if (sbp->sb_logsectsize || sbp->sb_logsectlog) {
+		xfs_notice(mp,
+		"log sector size in bytes/log2 (0x%x/0x%x) are not zero",
+			sbp->sb_logsectsize, sbp->sb_logsectlog);
+		return -EFSCORRUPTED;
+	}
+
+	if (sbp->sb_logsunit > 1) {
+		if (sbp->sb_logsunit % sbp->sb_blocksize) {
+			xfs_notice(mp,
+		"log stripe unit 0x%x bytes must be a multiple of block size",
+				sbp->sb_logsunit);
+			return -EFSCORRUPTED;
+		}
+		if (sbp->sb_logsunit > XLOG_MAX_RECORD_BSIZE) {
+			xfs_notice(mp,
+		"log stripe unit 0x%x bytes over maximum size (0x%x bytes)",
+				sbp->sb_logsunit, XLOG_MAX_RECORD_BSIZE);
+			return -EFSCORRUPTED;
+		}
+	}
+
+	/* Validate the realtime geometry; stolen from xfs_repair */
+	if (sbp->sb_rextsize * sbp->sb_blocksize > XFS_MAX_RTEXTSIZE ||
+	    sbp->sb_rextsize * sbp->sb_blocksize < XFS_MIN_RTEXTSIZE) {
+		xfs_notice(mp,
+			"realtime extent sanity check failed");
+		return -EFSCORRUPTED;
+	}
+
+	if (sbp->sb_rblocks == 0) {
+		if (sbp->sb_rextents != 0 || sbp->sb_rbmblocks != 0 ||
+		    sbp->sb_rextslog != 0 || sbp->sb_frextents != 0) {
+			xfs_notice(mp,
+				"realtime zeroed geometry check failed");
+			return -EFSCORRUPTED;
+		}
+	} else {
+		uint64_t	rexts;
+		uint64_t	rbmblocks;
+
+		rexts = div_u64(sbp->sb_rblocks, sbp->sb_rextsize);
+		rbmblocks = howmany_64(sbp->sb_rextents,
+				       NBBY * sbp->sb_blocksize);
+
+		if (sbp->sb_rextents != rexts ||
+		    sbp->sb_rextslog != xfs_highbit32(sbp->sb_rextents) ||
+		    sbp->sb_rbmblocks != rbmblocks) {
+			xfs_notice(mp,
+				"realtime geometry sanity check failed");
+			return -EFSCORRUPTED;
+		}
+	}
+
+	/*
+	 * Either (sb_unit and !hasdalign) or (!sb_unit and hasdalign)
+	 * would imply the image is corrupted.
+	 */
+	has_dalign = sbp->sb_versionnum & XFS_SB_VERSION_DALIGNBIT;
+	if (!!sbp->sb_unit ^ has_dalign) {
+		xfs_notice(mp, "SB stripe alignment sanity check failed");
+		return -EFSCORRUPTED;
+	}
+
+	if (!xfs_validate_stripe_geometry(mp, XFS_FSB_TO_B(mp, sbp->sb_unit),
+			XFS_FSB_TO_B(mp, sbp->sb_width), 0, false))
+		return -EFSCORRUPTED;
+
+	/*
+	 * Currently only very few inode sizes are supported.
+	 */
+	switch (sbp->sb_inodesize) {
+	case 256:
+	case 512:
+	case 1024:
+	case 2048:
+		break;
+	default:
+		xfs_warn(mp, "inode size of %d bytes not supported",
+				sbp->sb_inodesize);
+		return -ENOSYS;
+	}
+
+	return 0;
+}
+
+void
+xfs_sb_quota_from_disk(struct xfs_sb *sbp)
+{
+	/*
+	 * older mkfs doesn't initialize quota inodes to NULLFSINO. This
+	 * leads to in-core values having two different values for a quota
+	 * inode to be invalid: 0 and NULLFSINO. Change it to a single value
+	 * NULLFSINO.
+	 *
+	 * Note that this change affect only the in-core values. These
+	 * values are not written back to disk unless any quota information
+	 * is written to the disk. Even in that case, sb_pquotino field is
+	 * not written to disk unless the superblock supports pquotino.
+	 */
+	if (sbp->sb_uquotino == 0)
+		sbp->sb_uquotino = NULLFSINO;
+	if (sbp->sb_gquotino == 0)
+		sbp->sb_gquotino = NULLFSINO;
+	if (sbp->sb_pquotino == 0)
+		sbp->sb_pquotino = NULLFSINO;
+
+	/*
+	 * We need to do these manipilations only if we are working
+	 * with an older version of on-disk superblock.
+	 */
+	if (xfs_sb_is_v5(sbp))
+		return;
+
+	if (sbp->sb_qflags & XFS_OQUOTA_ENFD)
+		sbp->sb_qflags |= (sbp->sb_qflags & XFS_PQUOTA_ACCT) ?
+					XFS_PQUOTA_ENFD : XFS_GQUOTA_ENFD;
+	if (sbp->sb_qflags & XFS_OQUOTA_CHKD)
+		sbp->sb_qflags |= (sbp->sb_qflags & XFS_PQUOTA_ACCT) ?
+					XFS_PQUOTA_CHKD : XFS_GQUOTA_CHKD;
+	sbp->sb_qflags &= ~(XFS_OQUOTA_ENFD | XFS_OQUOTA_CHKD);
+
+	if (sbp->sb_qflags & XFS_PQUOTA_ACCT &&
+	    sbp->sb_gquotino != NULLFSINO)  {
+		/*
+		 * In older version of superblock, on-disk superblock only
+		 * has sb_gquotino, and in-core superblock has both sb_gquotino
+		 * and sb_pquotino. But, only one of them is supported at any
+		 * point of time. So, if PQUOTA is set in disk superblock,
+		 * copy over sb_gquotino to sb_pquotino.  The NULLFSINO test
+		 * above is to make sure we don't do this twice and wipe them
+		 * both out!
+		 */
+		sbp->sb_pquotino = sbp->sb_gquotino;
+		sbp->sb_gquotino = NULLFSINO;
+	}
+}
+
+static void
+__xfs_sb_from_disk(
+	struct xfs_sb	*to,
+	struct xfs_dsb	*from,
+	bool		convert_xquota)
+{
+	to->sb_magicnum = be32_to_cpu(from->sb_magicnum);
+	to->sb_blocksize = be32_to_cpu(from->sb_blocksize);
+	to->sb_dblocks = be64_to_cpu(from->sb_dblocks);
+	to->sb_rblocks = be64_to_cpu(from->sb_rblocks);
+	to->sb_rextents = be64_to_cpu(from->sb_rextents);
+	memcpy(&to->sb_uuid, &from->sb_uuid, sizeof(to->sb_uuid));
+	to->sb_logstart = be64_to_cpu(from->sb_logstart);
+	to->sb_rootino = be64_to_cpu(from->sb_rootino);
+	to->sb_rbmino = be64_to_cpu(from->sb_rbmino);
+	to->sb_rsumino = be64_to_cpu(from->sb_rsumino);
+	to->sb_rextsize = be32_to_cpu(from->sb_rextsize);
+	to->sb_agblocks = be32_to_cpu(from->sb_agblocks);
+	to->sb_agcount = be32_to_cpu(from->sb_agcount);
+	to->sb_rbmblocks = be32_to_cpu(from->sb_rbmblocks);
+	to->sb_logblocks = be32_to_cpu(from->sb_logblocks);
+	to->sb_versionnum = be16_to_cpu(from->sb_versionnum);
+	to->sb_sectsize = be16_to_cpu(from->sb_sectsize);
+	to->sb_inodesize = be16_to_cpu(from->sb_inodesize);
+	to->sb_inopblock = be16_to_cpu(from->sb_inopblock);
+	memcpy(&to->sb_fname, &from->sb_fname, sizeof(to->sb_fname));
+	to->sb_blocklog = from->sb_blocklog;
+	to->sb_sectlog = from->sb_sectlog;
+	to->sb_inodelog = from->sb_inodelog;
+	to->sb_inopblog = from->sb_inopblog;
+	to->sb_agblklog = from->sb_agblklog;
+	to->sb_rextslog = from->sb_rextslog;
+	to->sb_inprogress = from->sb_inprogress;
+	to->sb_imax_pct = from->sb_imax_pct;
+	to->sb_icount = be64_to_cpu(from->sb_icount);
+	to->sb_ifree = be64_to_cpu(from->sb_ifree);
+	to->sb_fdblocks = be64_to_cpu(from->sb_fdblocks);
+	to->sb_frextents = be64_to_cpu(from->sb_frextents);
+	to->sb_uquotino = be64_to_cpu(from->sb_uquotino);
+	to->sb_gquotino = be64_to_cpu(from->sb_gquotino);
+	to->sb_qflags = be16_to_cpu(from->sb_qflags);
+	to->sb_flags = from->sb_flags;
+	to->sb_shared_vn = from->sb_shared_vn;
+	to->sb_inoalignmt = be32_to_cpu(from->sb_inoalignmt);
+	to->sb_unit = be32_to_cpu(from->sb_unit);
+	to->sb_width = be32_to_cpu(from->sb_width);
+	to->sb_dirblklog = from->sb_dirblklog;
+	to->sb_logsectlog = from->sb_logsectlog;
+	to->sb_logsectsize = be16_to_cpu(from->sb_logsectsize);
+	to->sb_logsunit = be32_to_cpu(from->sb_logsunit);
+	to->sb_features2 = be32_to_cpu(from->sb_features2);
+	to->sb_bad_features2 = be32_to_cpu(from->sb_bad_features2);
+	to->sb_features_compat = be32_to_cpu(from->sb_features_compat);
+	to->sb_features_ro_compat = be32_to_cpu(from->sb_features_ro_compat);
+	to->sb_features_incompat = be32_to_cpu(from->sb_features_incompat);
+	to->sb_features_log_incompat =
+				be32_to_cpu(from->sb_features_log_incompat);
+	/* crc is only used on disk, not in memory; just init to 0 here. */
+	to->sb_crc = 0;
+	to->sb_spino_align = be32_to_cpu(from->sb_spino_align);
+	to->sb_pquotino = be64_to_cpu(from->sb_pquotino);
+	to->sb_lsn = be64_to_cpu(from->sb_lsn);
+	/*
+	 * sb_meta_uuid is only on disk if it differs from sb_uuid and the
+	 * feature flag is set; if not set we keep it only in memory.
+	 */
+	if (xfs_sb_is_v5(to) &&
+	    (to->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_META_UUID))
+		uuid_copy(&to->sb_meta_uuid, &from->sb_meta_uuid);
+	else
+		uuid_copy(&to->sb_meta_uuid, &from->sb_uuid);
+	/* Convert on-disk flags to in-memory flags? */
+	if (convert_xquota)
+		xfs_sb_quota_from_disk(to);
+}
+
+void
+xfs_sb_from_disk(
+	struct xfs_sb	*to,
+	struct xfs_dsb	*from)
+{
+	__xfs_sb_from_disk(to, from, true);
+}
+
+static void
+xfs_sb_quota_to_disk(
+	struct xfs_dsb	*to,
+	struct xfs_sb	*from)
+{
+	uint16_t	qflags = from->sb_qflags;
+
+	to->sb_uquotino = cpu_to_be64(from->sb_uquotino);
+
+	/*
+	 * The in-memory superblock quota state matches the v5 on-disk format so
+	 * just write them out and return
+	 */
+	if (xfs_sb_is_v5(from)) {
+		to->sb_qflags = cpu_to_be16(from->sb_qflags);
+		to->sb_gquotino = cpu_to_be64(from->sb_gquotino);
+		to->sb_pquotino = cpu_to_be64(from->sb_pquotino);
+		return;
+	}
+
+	/*
+	 * For older superblocks (v4), the in-core version of sb_qflags do not
+	 * have XFS_OQUOTA_* flags, whereas the on-disk version does.  So,
+	 * convert incore XFS_{PG}QUOTA_* flags to on-disk XFS_OQUOTA_* flags.
+	 */
+	qflags &= ~(XFS_PQUOTA_ENFD | XFS_PQUOTA_CHKD |
+			XFS_GQUOTA_ENFD | XFS_GQUOTA_CHKD);
+
+	if (from->sb_qflags &
+			(XFS_PQUOTA_ENFD | XFS_GQUOTA_ENFD))
+		qflags |= XFS_OQUOTA_ENFD;
+	if (from->sb_qflags &
+			(XFS_PQUOTA_CHKD | XFS_GQUOTA_CHKD))
+		qflags |= XFS_OQUOTA_CHKD;
+	to->sb_qflags = cpu_to_be16(qflags);
+
+	/*
+	 * GQUOTINO and PQUOTINO cannot be used together in versions
+	 * of superblock that do not have pquotino. from->sb_flags
+	 * tells us which quota is active and should be copied to
+	 * disk. If neither are active, we should NULL the inode.
+	 *
+	 * In all cases, the separate pquotino must remain 0 because it
+	 * is beyond the "end" of the valid non-pquotino superblock.
+	 */
+	if (from->sb_qflags & XFS_GQUOTA_ACCT)
+		to->sb_gquotino = cpu_to_be64(from->sb_gquotino);
+	else if (from->sb_qflags & XFS_PQUOTA_ACCT)
+		to->sb_gquotino = cpu_to_be64(from->sb_pquotino);
+	else {
+		/*
+		 * We can't rely on just the fields being logged to tell us
+		 * that it is safe to write NULLFSINO - we should only do that
+		 * if quotas are not actually enabled. Hence only write
+		 * NULLFSINO if both in-core quota inodes are NULL.
+		 */
+		if (from->sb_gquotino == NULLFSINO &&
+		    from->sb_pquotino == NULLFSINO)
+			to->sb_gquotino = cpu_to_be64(NULLFSINO);
+	}
+
+	to->sb_pquotino = 0;
+}
+
+void
+xfs_sb_to_disk(
+	struct xfs_dsb	*to,
+	struct xfs_sb	*from)
+{
+	xfs_sb_quota_to_disk(to, from);
+
+	to->sb_magicnum = cpu_to_be32(from->sb_magicnum);
+	to->sb_blocksize = cpu_to_be32(from->sb_blocksize);
+	to->sb_dblocks = cpu_to_be64(from->sb_dblocks);
+	to->sb_rblocks = cpu_to_be64(from->sb_rblocks);
+	to->sb_rextents = cpu_to_be64(from->sb_rextents);
+	memcpy(&to->sb_uuid, &from->sb_uuid, sizeof(to->sb_uuid));
+	to->sb_logstart = cpu_to_be64(from->sb_logstart);
+	to->sb_rootino = cpu_to_be64(from->sb_rootino);
+	to->sb_rbmino = cpu_to_be64(from->sb_rbmino);
+	to->sb_rsumino = cpu_to_be64(from->sb_rsumino);
+	to->sb_rextsize = cpu_to_be32(from->sb_rextsize);
+	to->sb_agblocks = cpu_to_be32(from->sb_agblocks);
+	to->sb_agcount = cpu_to_be32(from->sb_agcount);
+	to->sb_rbmblocks = cpu_to_be32(from->sb_rbmblocks);
+	to->sb_logblocks = cpu_to_be32(from->sb_logblocks);
+	to->sb_versionnum = cpu_to_be16(from->sb_versionnum);
+	to->sb_sectsize = cpu_to_be16(from->sb_sectsize);
+	to->sb_inodesize = cpu_to_be16(from->sb_inodesize);
+	to->sb_inopblock = cpu_to_be16(from->sb_inopblock);
+	memcpy(&to->sb_fname, &from->sb_fname, sizeof(to->sb_fname));
+	to->sb_blocklog = from->sb_blocklog;
+	to->sb_sectlog = from->sb_sectlog;
+	to->sb_inodelog = from->sb_inodelog;
+	to->sb_inopblog = from->sb_inopblog;
+	to->sb_agblklog = from->sb_agblklog;
+	to->sb_rextslog = from->sb_rextslog;
+	to->sb_inprogress = from->sb_inprogress;
+	to->sb_imax_pct = from->sb_imax_pct;
+	to->sb_icount = cpu_to_be64(from->sb_icount);
+	to->sb_ifree = cpu_to_be64(from->sb_ifree);
+	to->sb_fdblocks = cpu_to_be64(from->sb_fdblocks);
+	to->sb_frextents = cpu_to_be64(from->sb_frextents);
+
+	to->sb_flags = from->sb_flags;
+	to->sb_shared_vn = from->sb_shared_vn;
+	to->sb_inoalignmt = cpu_to_be32(from->sb_inoalignmt);
+	to->sb_unit = cpu_to_be32(from->sb_unit);
+	to->sb_width = cpu_to_be32(from->sb_width);
+	to->sb_dirblklog = from->sb_dirblklog;
+	to->sb_logsectlog = from->sb_logsectlog;
+	to->sb_logsectsize = cpu_to_be16(from->sb_logsectsize);
+	to->sb_logsunit = cpu_to_be32(from->sb_logsunit);
+
+	/*
+	 * We need to ensure that bad_features2 always matches features2.
+	 * Hence we enforce that here rather than having to remember to do it
+	 * everywhere else that updates features2.
+	 */
+	from->sb_bad_features2 = from->sb_features2;
+	to->sb_features2 = cpu_to_be32(from->sb_features2);
+	to->sb_bad_features2 = cpu_to_be32(from->sb_bad_features2);
+
+	if (!xfs_sb_is_v5(from))
+		return;
+
+	to->sb_features_compat = cpu_to_be32(from->sb_features_compat);
+	to->sb_features_ro_compat =
+			cpu_to_be32(from->sb_features_ro_compat);
+	to->sb_features_incompat =
+			cpu_to_be32(from->sb_features_incompat);
+	to->sb_features_log_incompat =
+			cpu_to_be32(from->sb_features_log_incompat);
+	to->sb_spino_align = cpu_to_be32(from->sb_spino_align);
+	to->sb_lsn = cpu_to_be64(from->sb_lsn);
+	if (from->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_META_UUID)
+		uuid_copy(&to->sb_meta_uuid, &from->sb_meta_uuid);
+}
+
+/*
+ * If the superblock has the CRC feature bit set or the CRC field is non-null,
+ * check that the CRC is valid.  We check the CRC field is non-null because a
+ * single bit error could clear the feature bit and unused parts of the
+ * superblock are supposed to be zero. Hence a non-null crc field indicates that
+ * we've potentially lost a feature bit and we should check it anyway.
+ *
+ * However, past bugs (i.e. in growfs) left non-zeroed regions beyond the
+ * last field in V4 secondary superblocks.  So for secondary superblocks,
+ * we are more forgiving, and ignore CRC failures if the primary doesn't
+ * indicate that the fs version is V5.
+ */
+static void
+xfs_sb_read_verify(
+	struct xfs_buf		*bp)
+{
+	struct xfs_sb		sb;
+	struct xfs_mount	*mp = bp->b_mount;
+	struct xfs_dsb		*dsb = bp->b_addr;
+	int			error;
+
+	/*
+	 * open code the version check to avoid needing to convert the entire
+	 * superblock from disk order just to check the version number
+	 */
+	if (dsb->sb_magicnum == cpu_to_be32(XFS_SB_MAGIC) &&
+	    (((be16_to_cpu(dsb->sb_versionnum) & XFS_SB_VERSION_NUMBITS) ==
+						XFS_SB_VERSION_5) ||
+	     dsb->sb_crc != 0)) {
+
+		if (!xfs_buf_verify_cksum(bp, XFS_SB_CRC_OFF)) {
+			/* Only fail bad secondaries on a known V5 filesystem */
+			if (xfs_buf_daddr(bp) == XFS_SB_DADDR ||
+			    xfs_has_crc(mp)) {
+				error = -EFSBADCRC;
+				goto out_error;
+			}
+		}
+	}
+
+	/*
+	 * Check all the superblock fields.  Don't byteswap the xquota flags
+	 * because _verify_common checks the on-disk values.
+	 */
+	__xfs_sb_from_disk(&sb, dsb, false);
+	error = xfs_validate_sb_common(mp, bp, &sb);
+	if (error)
+		goto out_error;
+	error = xfs_validate_sb_read(mp, &sb);
+
+out_error:
+	if (error == -EFSCORRUPTED || error == -EFSBADCRC)
+		xfs_verifier_error(bp, error, __this_address);
+	else if (error)
+		xfs_buf_ioerror(bp, error);
+}
+
+/*
+ * We may be probed for a filesystem match, so we may not want to emit
+ * messages when the superblock buffer is not actually an XFS superblock.
+ * If we find an XFS superblock, then run a normal, noisy mount because we are
+ * really going to mount it and want to know about errors.
+ */
+static void
+xfs_sb_quiet_read_verify(
+	struct xfs_buf	*bp)
+{
+	struct xfs_dsb	*dsb = bp->b_addr;
+
+	if (dsb->sb_magicnum == cpu_to_be32(XFS_SB_MAGIC)) {
+		/* XFS filesystem, verify noisily! */
+		xfs_sb_read_verify(bp);
+		return;
+	}
+	/* quietly fail */
+	xfs_buf_ioerror(bp, -EWRONGFS);
+}
+
+static void
+xfs_sb_write_verify(
+	struct xfs_buf		*bp)
+{
+	struct xfs_sb		sb;
+	struct xfs_mount	*mp = bp->b_mount;
+	struct xfs_buf_log_item	*bip = bp->b_log_item;
+	struct xfs_dsb		*dsb = bp->b_addr;
+	int			error;
+
+	/*
+	 * Check all the superblock fields.  Don't byteswap the xquota flags
+	 * because _verify_common checks the on-disk values.
+	 */
+	__xfs_sb_from_disk(&sb, dsb, false);
+	error = xfs_validate_sb_common(mp, bp, &sb);
+	if (error)
+		goto out_error;
+	error = xfs_validate_sb_write(mp, bp, &sb);
+	if (error)
+		goto out_error;
+
+	if (!xfs_sb_is_v5(&sb))
+		return;
+
+	if (bip)
+		dsb->sb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
+
+	xfs_buf_update_cksum(bp, XFS_SB_CRC_OFF);
+	return;
+
+out_error:
+	xfs_verifier_error(bp, error, __this_address);
+}
+
+const struct xfs_buf_ops xfs_sb_buf_ops = {
+	.name = "xfs_sb",
+	.magic = { cpu_to_be32(XFS_SB_MAGIC), cpu_to_be32(XFS_SB_MAGIC) },
+	.verify_read = xfs_sb_read_verify,
+	.verify_write = xfs_sb_write_verify,
+};
+
+const struct xfs_buf_ops xfs_sb_quiet_buf_ops = {
+	.name = "xfs_sb_quiet",
+	.magic = { cpu_to_be32(XFS_SB_MAGIC), cpu_to_be32(XFS_SB_MAGIC) },
+	.verify_read = xfs_sb_quiet_read_verify,
+	.verify_write = xfs_sb_write_verify,
+};
+
+/*
+ * xfs_mount_common
+ *
+ * Mount initialization code establishing various mount
+ * fields from the superblock associated with the given
+ * mount structure.
+ *
+ * Inode geometry are calculated in xfs_ialloc_setup_geometry.
+ */
+void
+xfs_sb_mount_common(
+	struct xfs_mount	*mp,
+	struct xfs_sb		*sbp)
+{
+	mp->m_agfrotor = 0;
+	atomic_set(&mp->m_agirotor, 0);
+	mp->m_maxagi = mp->m_sb.sb_agcount;
+	mp->m_blkbit_log = sbp->sb_blocklog + XFS_NBBYLOG;
+	mp->m_blkbb_log = sbp->sb_blocklog - BBSHIFT;
+	mp->m_sectbb_log = sbp->sb_sectlog - BBSHIFT;
+	mp->m_agno_log = xfs_highbit32(sbp->sb_agcount - 1) + 1;
+	mp->m_blockmask = sbp->sb_blocksize - 1;
+	mp->m_blockwsize = sbp->sb_blocksize >> XFS_WORDLOG;
+	mp->m_blockwmask = mp->m_blockwsize - 1;
+
+	mp->m_alloc_mxr[0] = xfs_allocbt_maxrecs(mp, sbp->sb_blocksize, 1);
+	mp->m_alloc_mxr[1] = xfs_allocbt_maxrecs(mp, sbp->sb_blocksize, 0);
+	mp->m_alloc_mnr[0] = mp->m_alloc_mxr[0] / 2;
+	mp->m_alloc_mnr[1] = mp->m_alloc_mxr[1] / 2;
+
+	mp->m_bmap_dmxr[0] = xfs_bmbt_maxrecs(mp, sbp->sb_blocksize, 1);
+	mp->m_bmap_dmxr[1] = xfs_bmbt_maxrecs(mp, sbp->sb_blocksize, 0);
+	mp->m_bmap_dmnr[0] = mp->m_bmap_dmxr[0] / 2;
+	mp->m_bmap_dmnr[1] = mp->m_bmap_dmxr[1] / 2;
+
+	mp->m_rmap_mxr[0] = xfs_rmapbt_maxrecs(sbp->sb_blocksize, 1);
+	mp->m_rmap_mxr[1] = xfs_rmapbt_maxrecs(sbp->sb_blocksize, 0);
+	mp->m_rmap_mnr[0] = mp->m_rmap_mxr[0] / 2;
+	mp->m_rmap_mnr[1] = mp->m_rmap_mxr[1] / 2;
+
+	mp->m_refc_mxr[0] = xfs_refcountbt_maxrecs(sbp->sb_blocksize, true);
+	mp->m_refc_mxr[1] = xfs_refcountbt_maxrecs(sbp->sb_blocksize, false);
+	mp->m_refc_mnr[0] = mp->m_refc_mxr[0] / 2;
+	mp->m_refc_mnr[1] = mp->m_refc_mxr[1] / 2;
+
+	mp->m_bsize = XFS_FSB_TO_BB(mp, 1);
+	mp->m_alloc_set_aside = xfs_alloc_set_aside(mp);
+	mp->m_ag_max_usable = xfs_alloc_ag_max_usable(mp);
+}
+
+/*
+ * xfs_log_sb() can be used to copy arbitrary changes to the in-core superblock
+ * into the superblock buffer to be logged.  It does not provide the higher
+ * level of locking that is needed to protect the in-core superblock from
+ * concurrent access.
+ */
+void
+xfs_log_sb(
+	struct xfs_trans	*tp)
+{
+	struct xfs_mount	*mp = tp->t_mountp;
+	struct xfs_buf		*bp = xfs_trans_getsb(tp);
+
+	/*
+	 * Lazy sb counters don't update the in-core superblock so do that now.
+	 * If this is at unmount, the counters will be exactly correct, but at
+	 * any other time they will only be ballpark correct because of
+	 * reservations that have been taken out percpu counters. If we have an
+	 * unclean shutdown, this will be corrected by log recovery rebuilding
+	 * the counters from the AGF block counts.
+	 *
+	 * Do not update sb_frextents here because it is not part of the lazy
+	 * sb counters, despite having a percpu counter. It is always kept
+	 * consistent with the ondisk rtbitmap by xfs_trans_apply_sb_deltas()
+	 * and hence we don't need have to update it here.
+	 */
+	if (xfs_has_lazysbcount(mp)) {
+		mp->m_sb.sb_icount = percpu_counter_sum(&mp->m_icount);
+		mp->m_sb.sb_ifree = min_t(uint64_t,
+				percpu_counter_sum(&mp->m_ifree),
+				mp->m_sb.sb_icount);
+		mp->m_sb.sb_fdblocks = percpu_counter_sum(&mp->m_fdblocks);
+	}
+
+	xfs_sb_to_disk(bp->b_addr, &mp->m_sb);
+	xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SB_BUF);
+	xfs_trans_log_buf(tp, bp, 0, sizeof(struct xfs_dsb) - 1);
+}
+
+/*
+ * xfs_sync_sb
+ *
+ * Sync the superblock to disk.
+ *
+ * Note that the caller is responsible for checking the frozen state of the
+ * filesystem. This procedure uses the non-blocking transaction allocator and
+ * thus will allow modifications to a frozen fs. This is required because this
+ * code can be called during the process of freezing where use of the high-level
+ * allocator would deadlock.
+ */
+int
+xfs_sync_sb(
+	struct xfs_mount	*mp,
+	bool			wait)
+{
+	struct xfs_trans	*tp;
+	int			error;
+
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_sb, 0, 0,
+			XFS_TRANS_NO_WRITECOUNT, &tp);
+	if (error)
+		return error;
+
+	xfs_log_sb(tp);
+	if (wait)
+		xfs_trans_set_sync(tp);
+	return xfs_trans_commit(tp);
+}
+
+/*
+ * Update all the secondary superblocks to match the new state of the primary.
+ * Because we are completely overwriting all the existing fields in the
+ * secondary superblock buffers, there is no need to read them in from disk.
+ * Just get a new buffer, stamp it and write it.
+ *
+ * The sb buffers need to be cached here so that we serialise against other
+ * operations that access the secondary superblocks, but we don't want to keep
+ * them in memory once it is written so we mark it as a one-shot buffer.
+ */
+int
+xfs_update_secondary_sbs(
+	struct xfs_mount	*mp)
+{
+	struct xfs_perag	*pag;
+	xfs_agnumber_t		agno = 1;
+	int			saved_error = 0;
+	int			error = 0;
+	LIST_HEAD		(buffer_list);
+
+	/* update secondary superblocks. */
+	for_each_perag_from(mp, agno, pag) {
+		struct xfs_buf		*bp;
+
+		error = xfs_buf_get(mp->m_ddev_targp,
+				 XFS_AG_DADDR(mp, pag->pag_agno, XFS_SB_DADDR),
+				 XFS_FSS_TO_BB(mp, 1), &bp);
+		/*
+		 * If we get an error reading or writing alternate superblocks,
+		 * continue.  xfs_repair chooses the "best" superblock based
+		 * on most matches; if we break early, we'll leave more
+		 * superblocks un-updated than updated, and xfs_repair may
+		 * pick them over the properly-updated primary.
+		 */
+		if (error) {
+			xfs_warn(mp,
+		"error allocating secondary superblock for ag %d",
+				pag->pag_agno);
+			if (!saved_error)
+				saved_error = error;
+			continue;
+		}
+
+		bp->b_ops = &xfs_sb_buf_ops;
+		xfs_buf_oneshot(bp);
+		xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
+		xfs_sb_to_disk(bp->b_addr, &mp->m_sb);
+		xfs_buf_delwri_queue(bp, &buffer_list);
+		xfs_buf_relse(bp);
+
+		/* don't hold too many buffers at once */
+		if (agno % 16)
+			continue;
+
+		error = xfs_buf_delwri_submit(&buffer_list);
+		if (error) {
+			xfs_warn(mp,
+		"write error %d updating a secondary superblock near ag %d",
+				error, pag->pag_agno);
+			if (!saved_error)
+				saved_error = error;
+			continue;
+		}
+	}
+	error = xfs_buf_delwri_submit(&buffer_list);
+	if (error) {
+		xfs_warn(mp,
+		"write error %d updating a secondary superblock near ag %d",
+			error, agno);
+	}
+
+	return saved_error ? saved_error : error;
+}
+
+/*
+ * Same behavior as xfs_sync_sb, except that it is always synchronous and it
+ * also writes the superblock buffer to disk sector 0 immediately.
+ */
+int
+xfs_sync_sb_buf(
+	struct xfs_mount	*mp)
+{
+	struct xfs_trans	*tp;
+	struct xfs_buf		*bp;
+	int			error;
+
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_sb, 0, 0, 0, &tp);
+	if (error)
+		return error;
+
+	bp = xfs_trans_getsb(tp);
+	xfs_log_sb(tp);
+	xfs_trans_bhold(tp, bp);
+	xfs_trans_set_sync(tp);
+	error = xfs_trans_commit(tp);
+	if (error)
+		goto out;
+	/*
+	 * write out the sb buffer to get the changes to disk
+	 */
+	error = xfs_bwrite(bp);
+out:
+	xfs_buf_relse(bp);
+	return error;
+}
+
+void
+xfs_fs_geometry(
+	struct xfs_mount	*mp,
+	struct xfs_fsop_geom	*geo,
+	int			struct_version)
+{
+	struct xfs_sb		*sbp = &mp->m_sb;
+
+	memset(geo, 0, sizeof(struct xfs_fsop_geom));
+
+	geo->blocksize = sbp->sb_blocksize;
+	geo->rtextsize = sbp->sb_rextsize;
+	geo->agblocks = sbp->sb_agblocks;
+	geo->agcount = sbp->sb_agcount;
+	geo->logblocks = sbp->sb_logblocks;
+	geo->sectsize = sbp->sb_sectsize;
+	geo->inodesize = sbp->sb_inodesize;
+	geo->imaxpct = sbp->sb_imax_pct;
+	geo->datablocks = sbp->sb_dblocks;
+	geo->rtblocks = sbp->sb_rblocks;
+	geo->rtextents = sbp->sb_rextents;
+	geo->logstart = sbp->sb_logstart;
+	BUILD_BUG_ON(sizeof(geo->uuid) != sizeof(sbp->sb_uuid));
+	memcpy(geo->uuid, &sbp->sb_uuid, sizeof(sbp->sb_uuid));
+
+	if (struct_version < 2)
+		return;
+
+	geo->sunit = sbp->sb_unit;
+	geo->swidth = sbp->sb_width;
+
+	if (struct_version < 3)
+		return;
+
+	geo->version = XFS_FSOP_GEOM_VERSION;
+	geo->flags = XFS_FSOP_GEOM_FLAGS_NLINK |
+		     XFS_FSOP_GEOM_FLAGS_DIRV2 |
+		     XFS_FSOP_GEOM_FLAGS_EXTFLG;
+	if (xfs_has_attr(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_ATTR;
+	if (xfs_has_quota(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_QUOTA;
+	if (xfs_has_align(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_IALIGN;
+	if (xfs_has_dalign(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_DALIGN;
+	if (xfs_has_asciici(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_DIRV2CI;
+	if (xfs_has_lazysbcount(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_LAZYSB;
+	if (xfs_has_attr2(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_ATTR2;
+	if (xfs_has_projid32(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_PROJID32;
+	if (xfs_has_crc(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_V5SB;
+	if (xfs_has_ftype(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_FTYPE;
+	if (xfs_has_finobt(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_FINOBT;
+	if (xfs_has_sparseinodes(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_SPINODES;
+	if (xfs_has_rmapbt(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_RMAPBT;
+	if (xfs_has_reflink(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_REFLINK;
+	if (xfs_has_bigtime(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_BIGTIME;
+	if (xfs_has_inobtcounts(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_INOBTCNT;
+	if (xfs_has_sector(mp)) {
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_SECTOR;
+		geo->logsectsize = sbp->sb_logsectsize;
+	} else {
+		geo->logsectsize = BBSIZE;
+	}
+	if (xfs_has_large_extent_counts(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_NREXT64;
+	geo->rtsectsize = sbp->sb_blocksize;
+	geo->dirblocksize = xfs_dir2_dirblock_bytes(sbp);
+
+	if (struct_version < 4)
+		return;
+
+	if (xfs_has_logv2(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_LOGV2;
+
+	geo->logsunit = sbp->sb_logsunit;
+
+	if (struct_version < 5)
+		return;
+
+	geo->version = XFS_FSOP_GEOM_VERSION_V5;
+}
+
+/* Read a secondary superblock. */
+int
+xfs_sb_read_secondary(
+	struct xfs_mount	*mp,
+	struct xfs_trans	*tp,
+	xfs_agnumber_t		agno,
+	struct xfs_buf		**bpp)
+{
+	struct xfs_buf		*bp;
+	int			error;
+
+	ASSERT(agno != 0 && agno != NULLAGNUMBER);
+	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
+			XFS_AG_DADDR(mp, agno, XFS_SB_BLOCK(mp)),
+			XFS_FSS_TO_BB(mp, 1), 0, &bp, &xfs_sb_buf_ops);
+	if (error)
+		return error;
+	xfs_buf_set_ref(bp, XFS_SSB_REF);
+	*bpp = bp;
+	return 0;
+}
+
+/* Get an uninitialised secondary superblock buffer. */
+int
+xfs_sb_get_secondary(
+	struct xfs_mount	*mp,
+	struct xfs_trans	*tp,
+	xfs_agnumber_t		agno,
+	struct xfs_buf		**bpp)
+{
+	struct xfs_buf		*bp;
+	int			error;
+
+	ASSERT(agno != 0 && agno != NULLAGNUMBER);
+	error = xfs_trans_get_buf(tp, mp->m_ddev_targp,
+			XFS_AG_DADDR(mp, agno, XFS_SB_BLOCK(mp)),
+			XFS_FSS_TO_BB(mp, 1), 0, &bp);
+	if (error)
+		return error;
+	bp->b_ops = &xfs_sb_buf_ops;
+	xfs_buf_oneshot(bp);
+	*bpp = bp;
+	return 0;
+}
+
+/*
+ * sunit, swidth, sectorsize(optional with 0) should be all in bytes,
+ * so users won't be confused by values in error messages.
+ */
+bool
+xfs_validate_stripe_geometry(
+	struct xfs_mount	*mp,
+	__s64			sunit,
+	__s64			swidth,
+	int			sectorsize,
+	bool			silent)
+{
+	if (swidth > INT_MAX) {
+		if (!silent)
+			xfs_notice(mp,
+"stripe width (%lld) is too large", swidth);
+		return false;
+	}
+
+	if (sunit > swidth) {
+		if (!silent)
+			xfs_notice(mp,
+"stripe unit (%lld) is larger than the stripe width (%lld)", sunit, swidth);
+		return false;
+	}
+
+	if (sectorsize && (int)sunit % sectorsize) {
+		if (!silent)
+			xfs_notice(mp,
+"stripe unit (%lld) must be a multiple of the sector size (%d)",
+				   sunit, sectorsize);
+		return false;
+	}
+
+	if (sunit && !swidth) {
+		if (!silent)
+			xfs_notice(mp,
+"invalid stripe unit (%lld) and stripe width of 0", sunit);
+		return false;
+	}
+
+	if (!sunit && swidth) {
+		if (!silent)
+			xfs_notice(mp,
+"invalid stripe width (%lld) and stripe unit of 0", swidth);
+		return false;
+	}
+
+	if (sunit && (int)swidth % (int)sunit) {
+		if (!silent)
+			xfs_notice(mp,
+"stripe width (%lld) must be a multiple of the stripe unit (%lld)",
+				   swidth, sunit);
+		return false;
+	}
+	return true;
+}