xfs: create libxfs infrastructure

To minimise the differences between kernel and userspace code,
split the kernel code into the same structure as the userspace code.
That is, the gneric core functionality of XFS is moved to a libxfs/
directory and treat it as a layering barrier in the XFS code.

This patch introduces the libxfs directory, the build infrastructure
and an initial source and header file to build. The libxfs directory
will contain the header files that are needed to build libxfs - most
of userspace does not care about the location of these header files
as they are accessed indirectly. Hence keeping them inside libxfs
makes it easy to track the changes and script the sync process as
the directory structure will be identical.

To allow this changeover to occur in the kernel code, there are some
temporary infrastructure in the makefiles to grab the header
filesystem from both locations. Once all the files are moved,
modifications will be made in the source code that will make the
need for these include directives go away.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

2 files changed, 1440 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
new file mode 100644
index 000000000000..06ad60b4b9fd
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -0,0 +1,819 @@
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, 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_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_ag.h"
+#include "xfs_mount.h"
+#include "xfs_inode.h"
+#include "xfs_ialloc.h"
+#include "xfs_alloc.h"
+#include "xfs_error.h"
+#include "xfs_trace.h"
+#include "xfs_cksum.h"
+#include "xfs_trans.h"
+#include "xfs_buf_item.h"
+#include "xfs_dinode.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_ialloc_btree.h"
+
+/*
+ * Physical superblock buffer manipulations. Shared with libxfs in userspace.
+ */
+
+static const struct {
+	short offset;
+	short type;	/* 0 = integer
+			 * 1 = binary / string (no translation)
+			 */
+} xfs_sb_info[] = {
+	{ offsetof(xfs_sb_t, sb_magicnum),	0 },
+	{ offsetof(xfs_sb_t, sb_blocksize),	0 },
+	{ offsetof(xfs_sb_t, sb_dblocks),	0 },
+	{ offsetof(xfs_sb_t, sb_rblocks),	0 },
+	{ offsetof(xfs_sb_t, sb_rextents),	0 },
+	{ offsetof(xfs_sb_t, sb_uuid),		1 },
+	{ offsetof(xfs_sb_t, sb_logstart),	0 },
+	{ offsetof(xfs_sb_t, sb_rootino),	0 },
+	{ offsetof(xfs_sb_t, sb_rbmino),	0 },
+	{ offsetof(xfs_sb_t, sb_rsumino),	0 },
+	{ offsetof(xfs_sb_t, sb_rextsize),	0 },
+	{ offsetof(xfs_sb_t, sb_agblocks),	0 },
+	{ offsetof(xfs_sb_t, sb_agcount),	0 },
+	{ offsetof(xfs_sb_t, sb_rbmblocks),	0 },
+	{ offsetof(xfs_sb_t, sb_logblocks),	0 },
+	{ offsetof(xfs_sb_t, sb_versionnum),	0 },
+	{ offsetof(xfs_sb_t, sb_sectsize),	0 },
+	{ offsetof(xfs_sb_t, sb_inodesize),	0 },
+	{ offsetof(xfs_sb_t, sb_inopblock),	0 },
+	{ offsetof(xfs_sb_t, sb_fname[0]),	1 },
+	{ offsetof(xfs_sb_t, sb_blocklog),	0 },
+	{ offsetof(xfs_sb_t, sb_sectlog),	0 },
+	{ offsetof(xfs_sb_t, sb_inodelog),	0 },
+	{ offsetof(xfs_sb_t, sb_inopblog),	0 },
+	{ offsetof(xfs_sb_t, sb_agblklog),	0 },
+	{ offsetof(xfs_sb_t, sb_rextslog),	0 },
+	{ offsetof(xfs_sb_t, sb_inprogress),	0 },
+	{ offsetof(xfs_sb_t, sb_imax_pct),	0 },
+	{ offsetof(xfs_sb_t, sb_icount),	0 },
+	{ offsetof(xfs_sb_t, sb_ifree),		0 },
+	{ offsetof(xfs_sb_t, sb_fdblocks),	0 },
+	{ offsetof(xfs_sb_t, sb_frextents),	0 },
+	{ offsetof(xfs_sb_t, sb_uquotino),	0 },
+	{ offsetof(xfs_sb_t, sb_gquotino),	0 },
+	{ offsetof(xfs_sb_t, sb_qflags),	0 },
+	{ offsetof(xfs_sb_t, sb_flags),		0 },
+	{ offsetof(xfs_sb_t, sb_shared_vn),	0 },
+	{ offsetof(xfs_sb_t, sb_inoalignmt),	0 },
+	{ offsetof(xfs_sb_t, sb_unit),		0 },
+	{ offsetof(xfs_sb_t, sb_width),		0 },
+	{ offsetof(xfs_sb_t, sb_dirblklog),	0 },
+	{ offsetof(xfs_sb_t, sb_logsectlog),	0 },
+	{ offsetof(xfs_sb_t, sb_logsectsize),	0 },
+	{ offsetof(xfs_sb_t, sb_logsunit),	0 },
+	{ offsetof(xfs_sb_t, sb_features2),	0 },
+	{ offsetof(xfs_sb_t, sb_bad_features2),	0 },
+	{ offsetof(xfs_sb_t, sb_features_compat),	0 },
+	{ offsetof(xfs_sb_t, sb_features_ro_compat),	0 },
+	{ offsetof(xfs_sb_t, sb_features_incompat),	0 },
+	{ offsetof(xfs_sb_t, sb_features_log_incompat),	0 },
+	{ offsetof(xfs_sb_t, sb_crc),		0 },
+	{ offsetof(xfs_sb_t, sb_pad),		0 },
+	{ offsetof(xfs_sb_t, sb_pquotino),	0 },
+	{ offsetof(xfs_sb_t, sb_lsn),		0 },
+	{ sizeof(xfs_sb_t),			0 }
+};
+
+/*
+ * Reference counting access wrappers to the perag structures.
+ * Because we never free per-ag structures, the only thing we
+ * have to protect against changes is the tree structure itself.
+ */
+struct xfs_perag *
+xfs_perag_get(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		agno)
+{
+	struct xfs_perag	*pag;
+	int			ref = 0;
+
+	rcu_read_lock();
+	pag = radix_tree_lookup(&mp->m_perag_tree, agno);
+	if (pag) {
+		ASSERT(atomic_read(&pag->pag_ref) >= 0);
+		ref = atomic_inc_return(&pag->pag_ref);
+	}
+	rcu_read_unlock();
+	trace_xfs_perag_get(mp, agno, ref, _RET_IP_);
+	return pag;
+}
+
+/*
+ * search from @first to find the next perag with the given tag set.
+ */
+struct xfs_perag *
+xfs_perag_get_tag(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		first,
+	int			tag)
+{
+	struct xfs_perag	*pag;
+	int			found;
+	int			ref;
+
+	rcu_read_lock();
+	found = radix_tree_gang_lookup_tag(&mp->m_perag_tree,
+					(void **)&pag, first, 1, tag);
+	if (found <= 0) {
+		rcu_read_unlock();
+		return NULL;
+	}
+	ref = atomic_inc_return(&pag->pag_ref);
+	rcu_read_unlock();
+	trace_xfs_perag_get_tag(mp, pag->pag_agno, ref, _RET_IP_);
+	return pag;
+}
+
+void
+xfs_perag_put(
+	struct xfs_perag	*pag)
+{
+	int	ref;
+
+	ASSERT(atomic_read(&pag->pag_ref) > 0);
+	ref = atomic_dec_return(&pag->pag_ref);
+	trace_xfs_perag_put(pag->pag_mount, pag->pag_agno, ref, _RET_IP_);
+}
+
+/*
+ * Check the validity of the SB found.
+ */
+STATIC int
+xfs_mount_validate_sb(
+	xfs_mount_t	*mp,
+	xfs_sb_t	*sbp,
+	bool		check_inprogress,
+	bool		check_version)
+{
+
+	/*
+	 * If the log device and data device have the
+	 * same device number, the log is internal.
+	 * Consequently, the sb_logstart should be non-zero.  If
+	 * we have a zero sb_logstart in this case, we may be trying to mount
+	 * a volume filesystem in a non-volume manner.
+	 */
+	if (sbp->sb_magicnum != XFS_SB_MAGIC) {
+		xfs_warn(mp, "bad magic number");
+		return EWRONGFS;
+	}
+
+
+	if (!xfs_sb_good_version(sbp)) {
+		xfs_warn(mp, "bad version");
+		return EWRONGFS;
+	}
+
+	/*
+	 * Version 5 superblock feature mask validation. Reject combinations the
+	 * kernel cannot support up front before checking anything else. For
+	 * write validation, we don't need to check feature masks.
+	 */
+	if (check_version && XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5) {
+		if (xfs_sb_has_compat_feature(sbp,
+					XFS_SB_FEAT_COMPAT_UNKNOWN)) {
+			xfs_warn(mp,
+"Superblock has unknown compatible features (0x%x) enabled.\n"
+"Using a more recent kernel is recommended.",
+				(sbp->sb_features_compat &
+						XFS_SB_FEAT_COMPAT_UNKNOWN));
+		}
+
+		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 (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
+				xfs_warn(mp,
+"Attempted to mount read-only compatible filesystem read-write.\n"
+"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.\n"
+"Filesystem can not be safely mounted by this kernel.",
+				(sbp->sb_features_incompat &
+						XFS_SB_FEAT_INCOMPAT_UNKNOWN));
+			return EINVAL;
+		}
+	}
+
+	if (xfs_sb_version_has_pquotino(sbp)) {
+		if (sbp->sb_qflags & (XFS_OQUOTA_ENFD | XFS_OQUOTA_CHKD)) {
+			xfs_notice(mp,
+			   "Version 5 of Super block has XFS_OQUOTA bits.");
+			return EFSCORRUPTED;
+		}
+	} 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_[PQ]UOTA_{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;
+	}
+
+	/*
+	 * 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_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) ||
+	    (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;
+	}
+
+	/*
+	 * Until this is fixed only page-sized or smaller data blocks work.
+	 */
+	if (unlikely(sbp->sb_blocksize > PAGE_SIZE)) {
+		xfs_warn(mp,
+		"File system with blocksize %d bytes. "
+		"Only pagesize (%ld) or less will currently work.",
+				sbp->sb_blocksize, PAGE_SIZE);
+		return ENOSYS;
+	}
+
+	/*
+	 * 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;
+	}
+
+	if (xfs_sb_validate_fsb_count(sbp, sbp->sb_dblocks) ||
+	    xfs_sb_validate_fsb_count(sbp, sbp->sb_rblocks)) {
+		xfs_warn(mp,
+		"file system too large to be mounted on this system.");
+		return EFBIG;
+	}
+
+	if (check_inprogress && sbp->sb_inprogress) {
+		xfs_warn(mp, "Offline file system operation in progress!");
+		return EFSCORRUPTED;
+	}
+	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_version_has_pquotino(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)  {
+		/*
+		 * 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.
+		 */
+		sbp->sb_pquotino = sbp->sb_gquotino;
+		sbp->sb_gquotino = NULLFSINO;
+	}
+}
+
+void
+xfs_sb_from_disk(
+	struct xfs_sb	*to,
+	xfs_dsb_t	*from)
+{
+	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);
+	to->sb_pad = 0;
+	to->sb_pquotino = be64_to_cpu(from->sb_pquotino);
+	to->sb_lsn = be64_to_cpu(from->sb_lsn);
+}
+
+static inline void
+xfs_sb_quota_to_disk(
+	xfs_dsb_t	*to,
+	xfs_sb_t	*from,
+	__int64_t	*fields)
+{
+	__uint16_t	qflags = from->sb_qflags;
+
+	/*
+	 * We need to do these manipilations only if we are working
+	 * with an older version of on-disk superblock.
+	 */
+	if (xfs_sb_version_has_pquotino(from))
+		return;
+
+	if (*fields & XFS_SB_QFLAGS) {
+		/*
+		 * 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);
+		*fields &= ~XFS_SB_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 ((*fields & XFS_SB_GQUOTINO) &&
+				(from->sb_qflags & XFS_GQUOTA_ACCT))
+		to->sb_gquotino = cpu_to_be64(from->sb_gquotino);
+	else if ((*fields & XFS_SB_PQUOTINO) &&
+				(from->sb_qflags & XFS_PQUOTA_ACCT))
+		to->sb_gquotino = cpu_to_be64(from->sb_pquotino);
+
+	*fields &= ~(XFS_SB_PQUOTINO | XFS_SB_GQUOTINO);
+}
+
+/*
+ * Copy in core superblock to ondisk one.
+ *
+ * The fields argument is mask of superblock fields to copy.
+ */
+void
+xfs_sb_to_disk(
+	xfs_dsb_t	*to,
+	xfs_sb_t	*from,
+	__int64_t	fields)
+{
+	xfs_caddr_t	to_ptr = (xfs_caddr_t)to;
+	xfs_caddr_t	from_ptr = (xfs_caddr_t)from;
+	xfs_sb_field_t	f;
+	int		first;
+	int		size;
+
+	ASSERT(fields);
+	if (!fields)
+		return;
+
+	xfs_sb_quota_to_disk(to, from, &fields);
+	while (fields) {
+		f = (xfs_sb_field_t)xfs_lowbit64((__uint64_t)fields);
+		first = xfs_sb_info[f].offset;
+		size = xfs_sb_info[f + 1].offset - first;
+
+		ASSERT(xfs_sb_info[f].type == 0 || xfs_sb_info[f].type == 1);
+
+		if (size == 1 || xfs_sb_info[f].type == 1) {
+			memcpy(to_ptr + first, from_ptr + first, size);
+		} else {
+			switch (size) {
+			case 2:
+				*(__be16 *)(to_ptr + first) =
+				      cpu_to_be16(*(__u16 *)(from_ptr + first));
+				break;
+			case 4:
+				*(__be32 *)(to_ptr + first) =
+				      cpu_to_be32(*(__u32 *)(from_ptr + first));
+				break;
+			case 8:
+				*(__be64 *)(to_ptr + first) =
+				      cpu_to_be64(*(__u64 *)(from_ptr + first));
+				break;
+			default:
+				ASSERT(0);
+			}
+		}
+
+		fields &= ~(1LL << f);
+	}
+}
+
+static int
+xfs_sb_verify(
+	struct xfs_buf	*bp,
+	bool		check_version)
+{
+	struct xfs_mount *mp = bp->b_target->bt_mount;
+	struct xfs_sb	sb;
+
+	xfs_sb_from_disk(&sb, XFS_BUF_TO_SBP(bp));
+
+	/*
+	 * Only check the in progress field for the primary superblock as
+	 * mkfs.xfs doesn't clear it from secondary superblocks.
+	 */
+	return xfs_mount_validate_sb(mp, &sb, bp->b_bn == XFS_SB_DADDR,
+				     check_version);
+}
+
+/*
+ * 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_mount *mp = bp->b_target->bt_mount;
+	struct xfs_dsb	*dsb = XFS_BUF_TO_SBP(bp);
+	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 (bp->b_bn == XFS_SB_DADDR ||
+			    xfs_sb_version_hascrc(&mp->m_sb)) {
+				error = EFSBADCRC;
+				goto out_error;
+			}
+		}
+	}
+	error = xfs_sb_verify(bp, true);
+
+out_error:
+	if (error) {
+		xfs_buf_ioerror(bp, error);
+		if (error == EFSCORRUPTED || error == EFSBADCRC)
+			xfs_verifier_error(bp);
+	}
+}
+
+/*
+ * 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 = XFS_BUF_TO_SBP(bp);
+
+	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_mount	*mp = bp->b_target->bt_mount;
+	struct xfs_buf_log_item	*bip = bp->b_fspriv;
+	int			error;
+
+	error = xfs_sb_verify(bp, false);
+	if (error) {
+		xfs_buf_ioerror(bp, error);
+		xfs_verifier_error(bp);
+		return;
+	}
+
+	if (!xfs_sb_version_hascrc(&mp->m_sb))
+		return;
+
+	if (bip)
+		XFS_BUF_TO_SBP(bp)->sb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
+
+	xfs_buf_update_cksum(bp, XFS_SB_CRC_OFF);
+}
+
+const struct xfs_buf_ops xfs_sb_buf_ops = {
+	.verify_read = xfs_sb_read_verify,
+	.verify_write = xfs_sb_write_verify,
+};
+
+const struct xfs_buf_ops xfs_sb_quiet_buf_ops = {
+	.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
+ */
+void
+xfs_sb_mount_common(
+	struct xfs_mount *mp,
+	struct xfs_sb	*sbp)
+{
+	mp->m_agfrotor = mp->m_agirotor = 0;
+	spin_lock_init(&mp->m_agirotor_lock);
+	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_agino_log = sbp->sb_inopblog + sbp->sb_agblklog;
+	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_inobt_mxr[0] = xfs_inobt_maxrecs(mp, sbp->sb_blocksize, 1);
+	mp->m_inobt_mxr[1] = xfs_inobt_maxrecs(mp, sbp->sb_blocksize, 0);
+	mp->m_inobt_mnr[0] = mp->m_inobt_mxr[0] / 2;
+	mp->m_inobt_mnr[1] = mp->m_inobt_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_bsize = XFS_FSB_TO_BB(mp, 1);
+	mp->m_ialloc_inos = (int)MAX((__uint16_t)XFS_INODES_PER_CHUNK,
+					sbp->sb_inopblock);
+	mp->m_ialloc_blks = mp->m_ialloc_inos >> sbp->sb_inopblog;
+}
+
+/*
+ * xfs_initialize_perag_data
+ *
+ * Read in each per-ag structure so we can count up the number of
+ * allocated inodes, free inodes and used filesystem blocks as this
+ * information is no longer persistent in the superblock. Once we have
+ * this information, write it into the in-core superblock structure.
+ */
+int
+xfs_initialize_perag_data(
+	struct xfs_mount *mp,
+	xfs_agnumber_t	agcount)
+{
+	xfs_agnumber_t	index;
+	xfs_perag_t	*pag;
+	xfs_sb_t	*sbp = &mp->m_sb;
+	uint64_t	ifree = 0;
+	uint64_t	ialloc = 0;
+	uint64_t	bfree = 0;
+	uint64_t	bfreelst = 0;
+	uint64_t	btree = 0;
+	int		error;
+
+	for (index = 0; index < agcount; index++) {
+		/*
+		 * read the agf, then the agi. This gets us
+		 * all the information we need and populates the
+		 * per-ag structures for us.
+		 */
+		error = xfs_alloc_pagf_init(mp, NULL, index, 0);
+		if (error)
+			return error;
+
+		error = xfs_ialloc_pagi_init(mp, NULL, index);
+		if (error)
+			return error;
+		pag = xfs_perag_get(mp, index);
+		ifree += pag->pagi_freecount;
+		ialloc += pag->pagi_count;
+		bfree += pag->pagf_freeblks;
+		bfreelst += pag->pagf_flcount;
+		btree += pag->pagf_btreeblks;
+		xfs_perag_put(pag);
+	}
+	/*
+	 * Overwrite incore superblock counters with just-read data
+	 */
+	spin_lock(&mp->m_sb_lock);
+	sbp->sb_ifree = ifree;
+	sbp->sb_icount = ialloc;
+	sbp->sb_fdblocks = bfree + bfreelst + btree;
+	spin_unlock(&mp->m_sb_lock);
+
+	/* Fixup the per-cpu counters as well. */
+	xfs_icsb_reinit_counters(mp);
+
+	return 0;
+}
+
+/*
+ * xfs_mod_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_mod_sb(xfs_trans_t *tp, __int64_t fields)
+{
+	xfs_buf_t	*bp;
+	int		first;
+	int		last;
+	xfs_mount_t	*mp;
+	xfs_sb_field_t	f;
+
+	ASSERT(fields);
+	if (!fields)
+		return;
+	mp = tp->t_mountp;
+	bp = xfs_trans_getsb(tp, mp, 0);
+	first = sizeof(xfs_sb_t);
+	last = 0;
+
+	/* translate/copy */
+
+	xfs_sb_to_disk(XFS_BUF_TO_SBP(bp), &mp->m_sb, fields);
+
+	/* find modified range */
+	f = (xfs_sb_field_t)xfs_highbit64((__uint64_t)fields);
+	ASSERT((1LL << f) & XFS_SB_MOD_BITS);
+	last = xfs_sb_info[f + 1].offset - 1;
+
+	f = (xfs_sb_field_t)xfs_lowbit64((__uint64_t)fields);
+	ASSERT((1LL << f) & XFS_SB_MOD_BITS);
+	first = xfs_sb_info[f].offset;
+
+	xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SB_BUF);
+	xfs_trans_log_buf(tp, bp, first, last);
+}
diff --git a/fs/xfs/libxfs/xfs_sb.h b/fs/xfs/libxfs/xfs_sb.h
new file mode 100644
index 000000000000..c43c2d609a24
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_sb.h
@@ -0,0 +1,621 @@
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, 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
+ */
+#ifndef __XFS_SB_H__
+#define	__XFS_SB_H__
+
+/*
+ * Super block
+ * Fits into a sector-sized buffer at address 0 of each allocation group.
+ * Only the first of these is ever updated except during growfs.
+ */
+
+struct xfs_buf;
+struct xfs_mount;
+struct xfs_trans;
+
+#define	XFS_SB_MAGIC		0x58465342	/* 'XFSB' */
+#define	XFS_SB_VERSION_1	1		/* 5.3, 6.0.1, 6.1 */
+#define	XFS_SB_VERSION_2	2		/* 6.2 - attributes */
+#define	XFS_SB_VERSION_3	3		/* 6.2 - new inode version */
+#define	XFS_SB_VERSION_4	4		/* 6.2+ - bitmask version */
+#define	XFS_SB_VERSION_5	5		/* CRC enabled filesystem */
+#define	XFS_SB_VERSION_NUMBITS		0x000f
+#define	XFS_SB_VERSION_ALLFBITS		0xfff0
+#define	XFS_SB_VERSION_ATTRBIT		0x0010
+#define	XFS_SB_VERSION_NLINKBIT		0x0020
+#define	XFS_SB_VERSION_QUOTABIT		0x0040
+#define	XFS_SB_VERSION_ALIGNBIT		0x0080
+#define	XFS_SB_VERSION_DALIGNBIT	0x0100
+#define	XFS_SB_VERSION_SHAREDBIT	0x0200
+#define XFS_SB_VERSION_LOGV2BIT		0x0400
+#define XFS_SB_VERSION_SECTORBIT	0x0800
+#define	XFS_SB_VERSION_EXTFLGBIT	0x1000
+#define	XFS_SB_VERSION_DIRV2BIT		0x2000
+#define	XFS_SB_VERSION_BORGBIT		0x4000	/* ASCII only case-insens. */
+#define	XFS_SB_VERSION_MOREBITSBIT	0x8000
+
+/*
+ * Supported feature bit list is just all bits in the versionnum field because
+ * we've used them all up and understand them all. Except, of course, for the
+ * shared superblock bit, which nobody knows what it does and so is unsupported.
+ */
+#define	XFS_SB_VERSION_OKBITS		\
+	((XFS_SB_VERSION_NUMBITS | XFS_SB_VERSION_ALLFBITS) & \
+		~XFS_SB_VERSION_SHAREDBIT)
+
+/*
+ * There are two words to hold XFS "feature" bits: the original
+ * word, sb_versionnum, and sb_features2.  Whenever a bit is set in
+ * sb_features2, the feature bit XFS_SB_VERSION_MOREBITSBIT must be set.
+ *
+ * These defines represent bits in sb_features2.
+ */
+#define XFS_SB_VERSION2_RESERVED1BIT	0x00000001
+#define XFS_SB_VERSION2_LAZYSBCOUNTBIT	0x00000002	/* Superblk counters */
+#define XFS_SB_VERSION2_RESERVED4BIT	0x00000004
+#define XFS_SB_VERSION2_ATTR2BIT	0x00000008	/* Inline attr rework */
+#define XFS_SB_VERSION2_PARENTBIT	0x00000010	/* parent pointers */
+#define XFS_SB_VERSION2_PROJID32BIT	0x00000080	/* 32 bit project id */
+#define XFS_SB_VERSION2_CRCBIT		0x00000100	/* metadata CRCs */
+#define XFS_SB_VERSION2_FTYPE		0x00000200	/* inode type in dir */
+
+#define	XFS_SB_VERSION2_OKBITS		\
+	(XFS_SB_VERSION2_LAZYSBCOUNTBIT	| \
+	 XFS_SB_VERSION2_ATTR2BIT	| \
+	 XFS_SB_VERSION2_PROJID32BIT	| \
+	 XFS_SB_VERSION2_FTYPE)
+
+/*
+ * Superblock - in core version.  Must match the ondisk version below.
+ * Must be padded to 64 bit alignment.
+ */
+typedef struct xfs_sb {
+	__uint32_t	sb_magicnum;	/* magic number == XFS_SB_MAGIC */
+	__uint32_t	sb_blocksize;	/* logical block size, bytes */
+	xfs_drfsbno_t	sb_dblocks;	/* number of data blocks */
+	xfs_drfsbno_t	sb_rblocks;	/* number of realtime blocks */
+	xfs_drtbno_t	sb_rextents;	/* number of realtime extents */
+	uuid_t		sb_uuid;	/* file system unique id */
+	xfs_dfsbno_t	sb_logstart;	/* starting block of log if internal */
+	xfs_ino_t	sb_rootino;	/* root inode number */
+	xfs_ino_t	sb_rbmino;	/* bitmap inode for realtime extents */
+	xfs_ino_t	sb_rsumino;	/* summary inode for rt bitmap */
+	xfs_agblock_t	sb_rextsize;	/* realtime extent size, blocks */
+	xfs_agblock_t	sb_agblocks;	/* size of an allocation group */
+	xfs_agnumber_t	sb_agcount;	/* number of allocation groups */
+	xfs_extlen_t	sb_rbmblocks;	/* number of rt bitmap blocks */
+	xfs_extlen_t	sb_logblocks;	/* number of log blocks */
+	__uint16_t	sb_versionnum;	/* header version == XFS_SB_VERSION */
+	__uint16_t	sb_sectsize;	/* volume sector size, bytes */
+	__uint16_t	sb_inodesize;	/* inode size, bytes */
+	__uint16_t	sb_inopblock;	/* inodes per block */
+	char		sb_fname[12];	/* file system name */
+	__uint8_t	sb_blocklog;	/* log2 of sb_blocksize */
+	__uint8_t	sb_sectlog;	/* log2 of sb_sectsize */
+	__uint8_t	sb_inodelog;	/* log2 of sb_inodesize */
+	__uint8_t	sb_inopblog;	/* log2 of sb_inopblock */
+	__uint8_t	sb_agblklog;	/* log2 of sb_agblocks (rounded up) */
+	__uint8_t	sb_rextslog;	/* log2 of sb_rextents */
+	__uint8_t	sb_inprogress;	/* mkfs is in progress, don't mount */
+	__uint8_t	sb_imax_pct;	/* max % of fs for inode space */
+					/* statistics */
+	/*
+	 * These fields must remain contiguous.  If you really
+	 * want to change their layout, make sure you fix the
+	 * code in xfs_trans_apply_sb_deltas().
+	 */
+	__uint64_t	sb_icount;	/* allocated inodes */
+	__uint64_t	sb_ifree;	/* free inodes */
+	__uint64_t	sb_fdblocks;	/* free data blocks */
+	__uint64_t	sb_frextents;	/* free realtime extents */
+	/*
+	 * End contiguous fields.
+	 */
+	xfs_ino_t	sb_uquotino;	/* user quota inode */
+	xfs_ino_t	sb_gquotino;	/* group quota inode */
+	__uint16_t	sb_qflags;	/* quota flags */
+	__uint8_t	sb_flags;	/* misc. flags */
+	__uint8_t	sb_shared_vn;	/* shared version number */
+	xfs_extlen_t	sb_inoalignmt;	/* inode chunk alignment, fsblocks */
+	__uint32_t	sb_unit;	/* stripe or raid unit */
+	__uint32_t	sb_width;	/* stripe or raid width */
+	__uint8_t	sb_dirblklog;	/* log2 of dir block size (fsbs) */
+	__uint8_t	sb_logsectlog;	/* log2 of the log sector size */
+	__uint16_t	sb_logsectsize;	/* sector size for the log, bytes */
+	__uint32_t	sb_logsunit;	/* stripe unit size for the log */
+	__uint32_t	sb_features2;	/* additional feature bits */
+
+	/*
+	 * bad features2 field as a result of failing to pad the sb
+	 * structure to 64 bits. Some machines will be using this field
+	 * for features2 bits. Easiest just to mark it bad and not use
+	 * it for anything else.
+	 */
+	__uint32_t	sb_bad_features2;
+
+	/* version 5 superblock fields start here */
+
+	/* feature masks */
+	__uint32_t	sb_features_compat;
+	__uint32_t	sb_features_ro_compat;
+	__uint32_t	sb_features_incompat;
+	__uint32_t	sb_features_log_incompat;
+
+	__uint32_t	sb_crc;		/* superblock crc */
+	__uint32_t	sb_pad;
+
+	xfs_ino_t	sb_pquotino;	/* project quota inode */
+	xfs_lsn_t	sb_lsn;		/* last write sequence */
+
+	/* must be padded to 64 bit alignment */
+} xfs_sb_t;
+
+#define XFS_SB_CRC_OFF		offsetof(struct xfs_sb, sb_crc)
+
+/*
+ * Superblock - on disk version.  Must match the in core version above.
+ * Must be padded to 64 bit alignment.
+ */
+typedef struct xfs_dsb {
+	__be32		sb_magicnum;	/* magic number == XFS_SB_MAGIC */
+	__be32		sb_blocksize;	/* logical block size, bytes */
+	__be64		sb_dblocks;	/* number of data blocks */
+	__be64		sb_rblocks;	/* number of realtime blocks */
+	__be64		sb_rextents;	/* number of realtime extents */
+	uuid_t		sb_uuid;	/* file system unique id */
+	__be64		sb_logstart;	/* starting block of log if internal */
+	__be64		sb_rootino;	/* root inode number */
+	__be64		sb_rbmino;	/* bitmap inode for realtime extents */
+	__be64		sb_rsumino;	/* summary inode for rt bitmap */
+	__be32		sb_rextsize;	/* realtime extent size, blocks */
+	__be32		sb_agblocks;	/* size of an allocation group */
+	__be32		sb_agcount;	/* number of allocation groups */
+	__be32		sb_rbmblocks;	/* number of rt bitmap blocks */
+	__be32		sb_logblocks;	/* number of log blocks */
+	__be16		sb_versionnum;	/* header version == XFS_SB_VERSION */
+	__be16		sb_sectsize;	/* volume sector size, bytes */
+	__be16		sb_inodesize;	/* inode size, bytes */
+	__be16		sb_inopblock;	/* inodes per block */
+	char		sb_fname[12];	/* file system name */
+	__u8		sb_blocklog;	/* log2 of sb_blocksize */
+	__u8		sb_sectlog;	/* log2 of sb_sectsize */
+	__u8		sb_inodelog;	/* log2 of sb_inodesize */
+	__u8		sb_inopblog;	/* log2 of sb_inopblock */
+	__u8		sb_agblklog;	/* log2 of sb_agblocks (rounded up) */
+	__u8		sb_rextslog;	/* log2 of sb_rextents */
+	__u8		sb_inprogress;	/* mkfs is in progress, don't mount */
+	__u8		sb_imax_pct;	/* max % of fs for inode space */
+					/* statistics */
+	/*
+	 * These fields must remain contiguous.  If you really
+	 * want to change their layout, make sure you fix the
+	 * code in xfs_trans_apply_sb_deltas().
+	 */
+	__be64		sb_icount;	/* allocated inodes */
+	__be64		sb_ifree;	/* free inodes */
+	__be64		sb_fdblocks;	/* free data blocks */
+	__be64		sb_frextents;	/* free realtime extents */
+	/*
+	 * End contiguous fields.
+	 */
+	__be64		sb_uquotino;	/* user quota inode */
+	__be64		sb_gquotino;	/* group quota inode */
+	__be16		sb_qflags;	/* quota flags */
+	__u8		sb_flags;	/* misc. flags */
+	__u8		sb_shared_vn;	/* shared version number */
+	__be32		sb_inoalignmt;	/* inode chunk alignment, fsblocks */
+	__be32		sb_unit;	/* stripe or raid unit */
+	__be32		sb_width;	/* stripe or raid width */
+	__u8		sb_dirblklog;	/* log2 of dir block size (fsbs) */
+	__u8		sb_logsectlog;	/* log2 of the log sector size */
+	__be16		sb_logsectsize;	/* sector size for the log, bytes */
+	__be32		sb_logsunit;	/* stripe unit size for the log */
+	__be32		sb_features2;	/* additional feature bits */
+	/*
+	 * bad features2 field as a result of failing to pad the sb
+	 * structure to 64 bits. Some machines will be using this field
+	 * for features2 bits. Easiest just to mark it bad and not use
+	 * it for anything else.
+	 */
+	__be32		sb_bad_features2;
+
+	/* version 5 superblock fields start here */
+
+	/* feature masks */
+	__be32		sb_features_compat;
+	__be32		sb_features_ro_compat;
+	__be32		sb_features_incompat;
+	__be32		sb_features_log_incompat;
+
+	__le32		sb_crc;		/* superblock crc */
+	__be32		sb_pad;
+
+	__be64		sb_pquotino;	/* project quota inode */
+	__be64		sb_lsn;		/* last write sequence */
+
+	/* must be padded to 64 bit alignment */
+} xfs_dsb_t;
+
+/*
+ * Sequence number values for the fields.
+ */
+typedef enum {
+	XFS_SBS_MAGICNUM, XFS_SBS_BLOCKSIZE, XFS_SBS_DBLOCKS, XFS_SBS_RBLOCKS,
+	XFS_SBS_REXTENTS, XFS_SBS_UUID, XFS_SBS_LOGSTART, XFS_SBS_ROOTINO,
+	XFS_SBS_RBMINO, XFS_SBS_RSUMINO, XFS_SBS_REXTSIZE, XFS_SBS_AGBLOCKS,
+	XFS_SBS_AGCOUNT, XFS_SBS_RBMBLOCKS, XFS_SBS_LOGBLOCKS,
+	XFS_SBS_VERSIONNUM, XFS_SBS_SECTSIZE, XFS_SBS_INODESIZE,
+	XFS_SBS_INOPBLOCK, XFS_SBS_FNAME, XFS_SBS_BLOCKLOG,
+	XFS_SBS_SECTLOG, XFS_SBS_INODELOG, XFS_SBS_INOPBLOG, XFS_SBS_AGBLKLOG,
+	XFS_SBS_REXTSLOG, XFS_SBS_INPROGRESS, XFS_SBS_IMAX_PCT, XFS_SBS_ICOUNT,
+	XFS_SBS_IFREE, XFS_SBS_FDBLOCKS, XFS_SBS_FREXTENTS, XFS_SBS_UQUOTINO,
+	XFS_SBS_GQUOTINO, XFS_SBS_QFLAGS, XFS_SBS_FLAGS, XFS_SBS_SHARED_VN,
+	XFS_SBS_INOALIGNMT, XFS_SBS_UNIT, XFS_SBS_WIDTH, XFS_SBS_DIRBLKLOG,
+	XFS_SBS_LOGSECTLOG, XFS_SBS_LOGSECTSIZE, XFS_SBS_LOGSUNIT,
+	XFS_SBS_FEATURES2, XFS_SBS_BAD_FEATURES2, XFS_SBS_FEATURES_COMPAT,
+	XFS_SBS_FEATURES_RO_COMPAT, XFS_SBS_FEATURES_INCOMPAT,
+	XFS_SBS_FEATURES_LOG_INCOMPAT, XFS_SBS_CRC, XFS_SBS_PAD,
+	XFS_SBS_PQUOTINO, XFS_SBS_LSN,
+	XFS_SBS_FIELDCOUNT
+} xfs_sb_field_t;
+
+/*
+ * Mask values, defined based on the xfs_sb_field_t values.
+ * Only define the ones we're using.
+ */
+#define	XFS_SB_MVAL(x)		(1LL << XFS_SBS_ ## x)
+#define	XFS_SB_UUID		XFS_SB_MVAL(UUID)
+#define	XFS_SB_FNAME		XFS_SB_MVAL(FNAME)
+#define	XFS_SB_ROOTINO		XFS_SB_MVAL(ROOTINO)
+#define	XFS_SB_RBMINO		XFS_SB_MVAL(RBMINO)
+#define	XFS_SB_RSUMINO		XFS_SB_MVAL(RSUMINO)
+#define	XFS_SB_VERSIONNUM	XFS_SB_MVAL(VERSIONNUM)
+#define XFS_SB_UQUOTINO		XFS_SB_MVAL(UQUOTINO)
+#define XFS_SB_GQUOTINO		XFS_SB_MVAL(GQUOTINO)
+#define XFS_SB_QFLAGS		XFS_SB_MVAL(QFLAGS)
+#define XFS_SB_SHARED_VN	XFS_SB_MVAL(SHARED_VN)
+#define XFS_SB_UNIT		XFS_SB_MVAL(UNIT)
+#define XFS_SB_WIDTH		XFS_SB_MVAL(WIDTH)
+#define XFS_SB_ICOUNT		XFS_SB_MVAL(ICOUNT)
+#define XFS_SB_IFREE		XFS_SB_MVAL(IFREE)
+#define XFS_SB_FDBLOCKS		XFS_SB_MVAL(FDBLOCKS)
+#define XFS_SB_FEATURES2	XFS_SB_MVAL(FEATURES2)
+#define XFS_SB_BAD_FEATURES2	XFS_SB_MVAL(BAD_FEATURES2)
+#define XFS_SB_FEATURES_COMPAT	XFS_SB_MVAL(FEATURES_COMPAT)
+#define XFS_SB_FEATURES_RO_COMPAT XFS_SB_MVAL(FEATURES_RO_COMPAT)
+#define XFS_SB_FEATURES_INCOMPAT XFS_SB_MVAL(FEATURES_INCOMPAT)
+#define XFS_SB_FEATURES_LOG_INCOMPAT XFS_SB_MVAL(FEATURES_LOG_INCOMPAT)
+#define XFS_SB_CRC		XFS_SB_MVAL(CRC)
+#define XFS_SB_PQUOTINO		XFS_SB_MVAL(PQUOTINO)
+#define	XFS_SB_NUM_BITS		((int)XFS_SBS_FIELDCOUNT)
+#define	XFS_SB_ALL_BITS		((1LL << XFS_SB_NUM_BITS) - 1)
+#define	XFS_SB_MOD_BITS		\
+	(XFS_SB_UUID | XFS_SB_ROOTINO | XFS_SB_RBMINO | XFS_SB_RSUMINO | \
+	 XFS_SB_VERSIONNUM | XFS_SB_UQUOTINO | XFS_SB_GQUOTINO | \
+	 XFS_SB_QFLAGS | XFS_SB_SHARED_VN | XFS_SB_UNIT | XFS_SB_WIDTH | \
+	 XFS_SB_ICOUNT | XFS_SB_IFREE | XFS_SB_FDBLOCKS | XFS_SB_FEATURES2 | \
+	 XFS_SB_BAD_FEATURES2 | XFS_SB_FEATURES_COMPAT | \
+	 XFS_SB_FEATURES_RO_COMPAT | XFS_SB_FEATURES_INCOMPAT | \
+	 XFS_SB_FEATURES_LOG_INCOMPAT | XFS_SB_PQUOTINO)
+
+
+/*
+ * Misc. Flags - warning - these will be cleared by xfs_repair unless
+ * a feature bit is set when the flag is used.
+ */
+#define XFS_SBF_NOFLAGS		0x00	/* no flags set */
+#define XFS_SBF_READONLY	0x01	/* only read-only mounts allowed */
+
+/*
+ * define max. shared version we can interoperate with
+ */
+#define XFS_SB_MAX_SHARED_VN	0
+
+#define	XFS_SB_VERSION_NUM(sbp)	((sbp)->sb_versionnum & XFS_SB_VERSION_NUMBITS)
+
+/*
+ * The first XFS version we support is a v4 superblock with V2 directories.
+ */
+static inline bool xfs_sb_good_v4_features(struct xfs_sb *sbp)
+{
+	if (!(sbp->sb_versionnum & XFS_SB_VERSION_DIRV2BIT))
+		return false;
+
+	/* check for unknown features in the fs */
+	if ((sbp->sb_versionnum & ~XFS_SB_VERSION_OKBITS) ||
+	    ((sbp->sb_versionnum & XFS_SB_VERSION_MOREBITSBIT) &&
+	     (sbp->sb_features2 & ~XFS_SB_VERSION2_OKBITS)))
+		return false;
+
+	return true;
+}
+
+static inline bool xfs_sb_good_version(struct xfs_sb *sbp)
+{
+	if (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5)
+		return true;
+	if (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4)
+		return xfs_sb_good_v4_features(sbp);
+	return false;
+}
+
+/*
+ * Detect a mismatched features2 field.  Older kernels read/wrote
+ * this into the wrong slot, so to be safe we keep them in sync.
+ */
+static inline bool xfs_sb_has_mismatched_features2(struct xfs_sb *sbp)
+{
+	return sbp->sb_bad_features2 != sbp->sb_features2;
+}
+
+static inline bool xfs_sb_version_hasattr(struct xfs_sb *sbp)
+{
+	return (sbp->sb_versionnum & XFS_SB_VERSION_ATTRBIT);
+}
+
+static inline void xfs_sb_version_addattr(struct xfs_sb *sbp)
+{
+	sbp->sb_versionnum |= XFS_SB_VERSION_ATTRBIT;
+}
+
+static inline bool xfs_sb_version_hasquota(struct xfs_sb *sbp)
+{
+	return (sbp->sb_versionnum & XFS_SB_VERSION_QUOTABIT);
+}
+
+static inline void xfs_sb_version_addquota(struct xfs_sb *sbp)
+{
+	sbp->sb_versionnum |= XFS_SB_VERSION_QUOTABIT;
+}
+
+static inline bool xfs_sb_version_hasalign(struct xfs_sb *sbp)
+{
+	return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 ||
+		(sbp->sb_versionnum & XFS_SB_VERSION_ALIGNBIT));
+}
+
+static inline bool xfs_sb_version_hasdalign(struct xfs_sb *sbp)
+{
+	return (sbp->sb_versionnum & XFS_SB_VERSION_DALIGNBIT);
+}
+
+static inline bool xfs_sb_version_haslogv2(struct xfs_sb *sbp)
+{
+	return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 ||
+	       (sbp->sb_versionnum & XFS_SB_VERSION_LOGV2BIT);
+}
+
+static inline bool xfs_sb_version_hasextflgbit(struct xfs_sb *sbp)
+{
+	return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 ||
+	       (sbp->sb_versionnum & XFS_SB_VERSION_EXTFLGBIT);
+}
+
+static inline bool xfs_sb_version_hassector(struct xfs_sb *sbp)
+{
+	return (sbp->sb_versionnum & XFS_SB_VERSION_SECTORBIT);
+}
+
+static inline bool xfs_sb_version_hasasciici(struct xfs_sb *sbp)
+{
+	return (sbp->sb_versionnum & XFS_SB_VERSION_BORGBIT);
+}
+
+static inline bool xfs_sb_version_hasmorebits(struct xfs_sb *sbp)
+{
+	return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 ||
+	       (sbp->sb_versionnum & XFS_SB_VERSION_MOREBITSBIT);
+}
+
+/*
+ * sb_features2 bit version macros.
+ */
+static inline bool xfs_sb_version_haslazysbcount(struct xfs_sb *sbp)
+{
+	return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5) ||
+	       (xfs_sb_version_hasmorebits(sbp) &&
+		(sbp->sb_features2 & XFS_SB_VERSION2_LAZYSBCOUNTBIT));
+}
+
+static inline bool xfs_sb_version_hasattr2(struct xfs_sb *sbp)
+{
+	return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5) ||
+	       (xfs_sb_version_hasmorebits(sbp) &&
+		(sbp->sb_features2 & XFS_SB_VERSION2_ATTR2BIT));
+}
+
+static inline void xfs_sb_version_addattr2(struct xfs_sb *sbp)
+{
+	sbp->sb_versionnum |= XFS_SB_VERSION_MOREBITSBIT;
+	sbp->sb_features2 |= XFS_SB_VERSION2_ATTR2BIT;
+	sbp->sb_bad_features2 |= XFS_SB_VERSION2_ATTR2BIT;
+}
+
+static inline void xfs_sb_version_removeattr2(struct xfs_sb *sbp)
+{
+	sbp->sb_features2 &= ~XFS_SB_VERSION2_ATTR2BIT;
+	sbp->sb_bad_features2 &= ~XFS_SB_VERSION2_ATTR2BIT;
+	if (!sbp->sb_features2)
+		sbp->sb_versionnum &= ~XFS_SB_VERSION_MOREBITSBIT;
+}
+
+static inline bool xfs_sb_version_hasprojid32bit(struct xfs_sb *sbp)
+{
+	return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5) ||
+	       (xfs_sb_version_hasmorebits(sbp) &&
+		(sbp->sb_features2 & XFS_SB_VERSION2_PROJID32BIT));
+}
+
+static inline void xfs_sb_version_addprojid32bit(struct xfs_sb *sbp)
+{
+	sbp->sb_versionnum |= XFS_SB_VERSION_MOREBITSBIT;
+	sbp->sb_features2 |= XFS_SB_VERSION2_PROJID32BIT;
+	sbp->sb_bad_features2 |= XFS_SB_VERSION2_PROJID32BIT;
+}
+
+/*
+ * Extended v5 superblock feature masks. These are to be used for new v5
+ * superblock features only.
+ *
+ * Compat features are new features that old kernels will not notice or affect
+ * and so can mount read-write without issues.
+ *
+ * RO-Compat (read only) are features that old kernels can read but will break
+ * if they write. Hence only read-only mounts of such filesystems are allowed on
+ * kernels that don't support the feature bit.
+ *
+ * InCompat features are features which old kernels will not understand and so
+ * must not mount.
+ *
+ * Log-InCompat features are for changes to log formats or new transactions that
+ * can't be replayed on older kernels. The fields are set when the filesystem is
+ * mounted, and a clean unmount clears the fields.
+ */
+#define XFS_SB_FEAT_COMPAT_ALL 0
+#define XFS_SB_FEAT_COMPAT_UNKNOWN	~XFS_SB_FEAT_COMPAT_ALL
+static inline bool
+xfs_sb_has_compat_feature(
+	struct xfs_sb	*sbp,
+	__uint32_t	feature)
+{
+	return (sbp->sb_features_compat & feature) != 0;
+}
+
+#define XFS_SB_FEAT_RO_COMPAT_FINOBT   (1 << 0)		/* free inode btree */
+#define XFS_SB_FEAT_RO_COMPAT_ALL \
+		(XFS_SB_FEAT_RO_COMPAT_FINOBT)
+#define XFS_SB_FEAT_RO_COMPAT_UNKNOWN	~XFS_SB_FEAT_RO_COMPAT_ALL
+static inline bool
+xfs_sb_has_ro_compat_feature(
+	struct xfs_sb	*sbp,
+	__uint32_t	feature)
+{
+	return (sbp->sb_features_ro_compat & feature) != 0;
+}
+
+#define XFS_SB_FEAT_INCOMPAT_FTYPE	(1 << 0)	/* filetype in dirent */
+#define XFS_SB_FEAT_INCOMPAT_ALL \
+		(XFS_SB_FEAT_INCOMPAT_FTYPE)
+
+#define XFS_SB_FEAT_INCOMPAT_UNKNOWN	~XFS_SB_FEAT_INCOMPAT_ALL
+static inline bool
+xfs_sb_has_incompat_feature(
+	struct xfs_sb	*sbp,
+	__uint32_t	feature)
+{
+	return (sbp->sb_features_incompat & feature) != 0;
+}
+
+#define XFS_SB_FEAT_INCOMPAT_LOG_ALL 0
+#define XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN	~XFS_SB_FEAT_INCOMPAT_LOG_ALL
+static inline bool
+xfs_sb_has_incompat_log_feature(
+	struct xfs_sb	*sbp,
+	__uint32_t	feature)
+{
+	return (sbp->sb_features_log_incompat & feature) != 0;
+}
+
+/*
+ * V5 superblock specific feature checks
+ */
+static inline int xfs_sb_version_hascrc(struct xfs_sb *sbp)
+{
+	return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5;
+}
+
+static inline int xfs_sb_version_has_pquotino(struct xfs_sb *sbp)
+{
+	return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5;
+}
+
+static inline int xfs_sb_version_hasftype(struct xfs_sb *sbp)
+{
+	return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 &&
+		xfs_sb_has_incompat_feature(sbp, XFS_SB_FEAT_INCOMPAT_FTYPE)) ||
+	       (xfs_sb_version_hasmorebits(sbp) &&
+		 (sbp->sb_features2 & XFS_SB_VERSION2_FTYPE));
+}
+
+static inline int xfs_sb_version_hasfinobt(xfs_sb_t *sbp)
+{
+	return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5) &&
+		(sbp->sb_features_ro_compat & XFS_SB_FEAT_RO_COMPAT_FINOBT);
+}
+
+/*
+ * end of superblock version macros
+ */
+
+static inline bool
+xfs_is_quota_inode(struct xfs_sb *sbp, xfs_ino_t ino)
+{
+	return (ino == sbp->sb_uquotino ||
+		ino == sbp->sb_gquotino ||
+		ino == sbp->sb_pquotino);
+}
+
+#define XFS_SB_DADDR		((xfs_daddr_t)0) /* daddr in filesystem/ag */
+#define	XFS_SB_BLOCK(mp)	XFS_HDR_BLOCK(mp, XFS_SB_DADDR)
+#define XFS_BUF_TO_SBP(bp)	((xfs_dsb_t *)((bp)->b_addr))
+
+#define	XFS_HDR_BLOCK(mp,d)	((xfs_agblock_t)XFS_BB_TO_FSBT(mp,d))
+#define	XFS_DADDR_TO_FSB(mp,d)	XFS_AGB_TO_FSB(mp, \
+			xfs_daddr_to_agno(mp,d), xfs_daddr_to_agbno(mp,d))
+#define	XFS_FSB_TO_DADDR(mp,fsbno)	XFS_AGB_TO_DADDR(mp, \
+			XFS_FSB_TO_AGNO(mp,fsbno), XFS_FSB_TO_AGBNO(mp,fsbno))
+
+/*
+ * File system sector to basic block conversions.
+ */
+#define XFS_FSS_TO_BB(mp,sec)	((sec) << (mp)->m_sectbb_log)
+
+/*
+ * File system block to basic block conversions.
+ */
+#define	XFS_FSB_TO_BB(mp,fsbno)	((fsbno) << (mp)->m_blkbb_log)
+#define	XFS_BB_TO_FSB(mp,bb)	\
+	(((bb) + (XFS_FSB_TO_BB(mp,1) - 1)) >> (mp)->m_blkbb_log)
+#define	XFS_BB_TO_FSBT(mp,bb)	((bb) >> (mp)->m_blkbb_log)
+
+/*
+ * File system block to byte conversions.
+ */
+#define XFS_FSB_TO_B(mp,fsbno)	((xfs_fsize_t)(fsbno) << (mp)->m_sb.sb_blocklog)
+#define XFS_B_TO_FSB(mp,b)	\
+	((((__uint64_t)(b)) + (mp)->m_blockmask) >> (mp)->m_sb.sb_blocklog)
+#define XFS_B_TO_FSBT(mp,b)	(((__uint64_t)(b)) >> (mp)->m_sb.sb_blocklog)
+#define XFS_B_FSB_OFFSET(mp,b)	((b) & (mp)->m_blockmask)
+
+/*
+ * perag get/put wrappers for ref counting
+ */
+extern struct xfs_perag *xfs_perag_get(struct xfs_mount *, xfs_agnumber_t);
+extern struct xfs_perag *xfs_perag_get_tag(struct xfs_mount *, xfs_agnumber_t,
+					   int tag);
+extern void	xfs_perag_put(struct xfs_perag *pag);
+extern int	xfs_initialize_perag_data(struct xfs_mount *, xfs_agnumber_t);
+
+extern void	xfs_sb_calc_crc(struct xfs_buf	*);
+extern void	xfs_mod_sb(struct xfs_trans *, __int64_t);
+extern void	xfs_sb_mount_common(struct xfs_mount *, struct xfs_sb *);
+extern void	xfs_sb_from_disk(struct xfs_sb *, struct xfs_dsb *);
+extern void	xfs_sb_to_disk(struct xfs_dsb *, struct xfs_sb *, __int64_t);
+extern void	xfs_sb_quota_from_disk(struct xfs_sb *sbp);
+
+#endif	/* __XFS_SB_H__ */