db/sb.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 */

#include "libxfs.h"
#include "libxlog.h"
#include "command.h"
#include "type.h"
#include "faddr.h"
#include "fprint.h"
#include "field.h"
#include "io.h"
#include "sb.h"
#include "bit.h"
#include "output.h"
#include "init.h"

#define uuid_equal(s,d)		(platform_uuid_compare((s),(d)) == 0)

static int	sb_f(int argc, char **argv);
static void     sb_help(void);
static int	uuid_f(int argc, char **argv);
static void     uuid_help(void);
static int	label_f(int argc, char **argv);
static void     label_help(void);
static int	version_f(int argc, char **argv);
static void     version_help(void);

static const cmdinfo_t	sb_cmd =
	{ "sb", NULL, sb_f, 0, 1, 1, N_("[agno]"),
	  N_("set current address to sb header"), sb_help };
static const cmdinfo_t	uuid_cmd =
	{ "uuid", NULL, uuid_f, 0, 1, 1, N_("[uuid]"),
	  N_("write/print FS uuid"), uuid_help };
static const cmdinfo_t	label_cmd =
	{ "label", NULL, label_f, 0, 1, 1, N_("[label]"),
	  N_("write/print FS label"), label_help };
static const cmdinfo_t	version_cmd =
	{ "version", NULL, version_f, 0, -1, 1, N_("[feature | [vnum fnum]]"),
	  N_("set feature bit(s) in the sb version field"), version_help };

void
sb_init(void)
{
	add_command(&sb_cmd);
	add_command(&uuid_cmd);
	add_command(&label_cmd);
	add_command(&version_cmd);
}

#define	OFF(f)	bitize(offsetof(xfs_sb_t, sb_ ## f))
#define	SZC(f)	szcount(xfs_sb_t, sb_ ## f)
const field_t	sb_flds[] = {
	{ "magicnum", FLDT_UINT32X, OI(OFF(magicnum)), C1, 0, TYP_NONE },
	{ "blocksize", FLDT_UINT32D, OI(OFF(blocksize)), C1, 0, TYP_NONE },
	{ "dblocks", FLDT_DRFSBNO, OI(OFF(dblocks)), C1, 0, TYP_NONE },
	{ "rblocks", FLDT_DRFSBNO, OI(OFF(rblocks)), C1, 0, TYP_NONE },
	{ "rextents", FLDT_DRTBNO, OI(OFF(rextents)), C1, 0, TYP_NONE },
	{ "uuid", FLDT_UUID, OI(OFF(uuid)), C1, 0, TYP_NONE },
	{ "logstart", FLDT_DFSBNO, OI(OFF(logstart)), C1, 0, TYP_LOG },
	{ "rootino", FLDT_INO, OI(OFF(rootino)), C1, 0, TYP_INODE },
	{ "rbmino", FLDT_INO, OI(OFF(rbmino)), C1, 0, TYP_INODE },
	{ "rsumino", FLDT_INO, OI(OFF(rsumino)), C1, 0, TYP_INODE },
	{ "rextsize", FLDT_AGBLOCK, OI(OFF(rextsize)), C1, 0, TYP_NONE },
	{ "agblocks", FLDT_AGBLOCK, OI(OFF(agblocks)), C1, 0, TYP_NONE },
	{ "agcount", FLDT_AGNUMBER, OI(OFF(agcount)), C1, 0, TYP_NONE },
	{ "rbmblocks", FLDT_EXTLEN, OI(OFF(rbmblocks)), C1, 0, TYP_NONE },
	{ "logblocks", FLDT_EXTLEN, OI(OFF(logblocks)), C1, 0, TYP_NONE },
	{ "versionnum", FLDT_UINT16X, OI(OFF(versionnum)), C1, 0, TYP_NONE },
	{ "sectsize", FLDT_UINT16D, OI(OFF(sectsize)), C1, 0, TYP_NONE },
	{ "inodesize", FLDT_UINT16D, OI(OFF(inodesize)), C1, 0, TYP_NONE },
	{ "inopblock", FLDT_UINT16D, OI(OFF(inopblock)), C1, 0, TYP_NONE },
	{ "fname", FLDT_CHARNS, OI(OFF(fname)), CI(SZC(fname)), 0, TYP_NONE },
	{ "blocklog", FLDT_UINT8D, OI(OFF(blocklog)), C1, 0, TYP_NONE },
	{ "sectlog", FLDT_UINT8D, OI(OFF(sectlog)), C1, 0, TYP_NONE },
	{ "inodelog", FLDT_UINT8D, OI(OFF(inodelog)), C1, 0, TYP_NONE },
	{ "inopblog", FLDT_UINT8D, OI(OFF(inopblog)), C1, 0, TYP_NONE },
	{ "agblklog", FLDT_UINT8D, OI(OFF(agblklog)), C1, 0, TYP_NONE },
	{ "rextslog", FLDT_UINT8D, OI(OFF(rextslog)), C1, 0, TYP_NONE },
	{ "inprogress", FLDT_UINT8D, OI(OFF(inprogress)), C1, 0, TYP_NONE },
	{ "imax_pct", FLDT_UINT8D, OI(OFF(imax_pct)), C1, 0, TYP_NONE },
	{ "icount", FLDT_UINT64D, OI(OFF(icount)), C1, 0, TYP_NONE },
	{ "ifree", FLDT_UINT64D, OI(OFF(ifree)), C1, 0, TYP_NONE },
	{ "fdblocks", FLDT_UINT64D, OI(OFF(fdblocks)), C1, 0, TYP_NONE },
	{ "frextents", FLDT_UINT64D, OI(OFF(frextents)), C1, 0, TYP_NONE },
	{ "uquotino", FLDT_INO, OI(OFF(uquotino)), C1, 0, TYP_INODE },
	{ "gquotino", FLDT_INO, OI(OFF(gquotino)), C1, 0, TYP_INODE },
	{ "qflags", FLDT_UINT16X, OI(OFF(qflags)), C1, 0, TYP_NONE },
	{ "flags", FLDT_UINT8X, OI(OFF(flags)), C1, 0, TYP_NONE },
	{ "shared_vn", FLDT_UINT8D, OI(OFF(shared_vn)), C1, 0, TYP_NONE },
	{ "inoalignmt", FLDT_EXTLEN, OI(OFF(inoalignmt)), C1, 0, TYP_NONE },
	{ "unit", FLDT_UINT32D, OI(OFF(unit)), C1, 0, TYP_NONE },
	{ "width", FLDT_UINT32D, OI(OFF(width)), C1, 0, TYP_NONE },
	{ "dirblklog", FLDT_UINT8D, OI(OFF(dirblklog)), C1, 0, TYP_NONE },
	{ "logsectlog", FLDT_UINT8D, OI(OFF(logsectlog)), C1, 0, TYP_NONE },
	{ "logsectsize", FLDT_UINT16D, OI(OFF(logsectsize)), C1, 0, TYP_NONE },
	{ "logsunit", FLDT_UINT32D, OI(OFF(logsunit)), C1, 0, TYP_NONE },
	{ "features2", FLDT_UINT32X, OI(OFF(features2)), C1, 0, TYP_NONE },
	{ "bad_features2", FLDT_UINT32X, OI(OFF(bad_features2)),
		C1, 0, TYP_NONE },
	{ "features_compat", FLDT_UINT32X, OI(OFF(features_compat)),
		C1, 0, TYP_NONE },
	{ "features_ro_compat", FLDT_UINT32X, OI(OFF(features_ro_compat)),
		C1, 0, TYP_NONE },
	{ "features_incompat", FLDT_UINT32X, OI(OFF(features_incompat)),
		C1, 0, TYP_NONE },
	{ "features_log_incompat", FLDT_UINT32X, OI(OFF(features_log_incompat)),
		C1, 0, TYP_NONE },
	{ "crc", FLDT_CRC, OI(OFF(crc)), C1, 0, TYP_NONE },
	{ "spino_align", FLDT_EXTLEN, OI(OFF(spino_align)), C1, 0, TYP_NONE },
	{ "pquotino", FLDT_INO, OI(OFF(pquotino)), C1, 0, TYP_INODE },
	{ "lsn", FLDT_UINT64X, OI(OFF(lsn)), C1, 0, TYP_NONE },
	{ "meta_uuid", FLDT_UUID, OI(OFF(meta_uuid)), C1, 0, TYP_NONE },
	{ NULL }
};

const field_t	sb_hfld[] = {
	{ "", FLDT_SB, OI(0), C1, 0, TYP_NONE },
	{ NULL }
};

static void
sb_help(void)
{
	dbprintf(_(
"\n"
" set allocation group superblock\n"
"\n"
" Example:\n"
"\n"
" 'sb 7' - set location to 7th allocation group superblock, set type to 'sb'\n"
"\n"
" Located in the first sector of each allocation group, the superblock\n"
" contains the base information for the filesystem.\n"
" The superblock in allocation group 0 is the primary.  The copies in the\n"
" remaining allocation groups only serve as backup for filesystem recovery.\n"
" The icount/ifree/fdblocks/frextents are only updated in superblock 0.\n"
"\n"
));
}

static int
sb_f(
	int		argc,
	char		**argv)
{
	xfs_agnumber_t	agno;
	char		*p;

	if (argc > 1) {
		agno = (xfs_agnumber_t)strtoul(argv[1], &p, 0);
		if (*p != '\0' || agno >= mp->m_sb.sb_agcount) {
			dbprintf(_("bad allocation group number %s\n"), argv[1]);
			return 0;
		}
		cur_agno = agno;
	} else if (cur_agno == NULLAGNUMBER)
		cur_agno = 0;
	ASSERT(typtab[TYP_SB].typnm == TYP_SB);
	set_cur(&typtab[TYP_SB],
		XFS_AG_DADDR(mp, cur_agno, XFS_SB_DADDR),
		XFS_FSS_TO_BB(mp, 1), DB_RING_ADD, NULL);
	return 0;
}

/*ARGSUSED*/
int
sb_size(
	void	*obj,
	int	startoff,
	int	idx)
{
	return bitize(mp->m_sb.sb_sectsize);
}

static int
get_sb(xfs_agnumber_t agno, xfs_sb_t *sb)
{
	push_cur();
	set_cur(&typtab[TYP_SB],
		XFS_AG_DADDR(mp, agno, XFS_SB_DADDR),
		XFS_FSS_TO_BB(mp, 1), DB_RING_IGN, NULL);

	if (!iocur_top->data) {
		dbprintf(_("can't read superblock for AG %u\n"), agno);
		pop_cur();
		return 0;
	}

	libxfs_sb_from_disk(sb, iocur_top->data);

	if (sb->sb_magicnum != XFS_SB_MAGIC) {
		dbprintf(_("bad sb magic # %#x in AG %u\n"),
			sb->sb_magicnum, agno);
		return 0;
	}
	if (!xfs_sb_good_version(sb)) {
		dbprintf(_("bad sb version # %#x in AG %u\n"),
			sb->sb_versionnum, agno);
		return 0;
	}
	if (agno == 0 && sb->sb_inprogress != 0) {
		dbprintf(_("mkfs not completed successfully\n"));
		return 0;
	}
	return 1;
}

/* workaround craziness in the xlog routines */
int xlog_recover_do_trans(struct xlog *log, xlog_recover_t *t, int p)
{
	return 0;
}

int
sb_logcheck(void)
{
	int		dirty;

	if (mp->m_sb.sb_logstart) {
		if (x.logdev && x.logdev != x.ddev) {
			dbprintf(_("aborting - external log specified for FS "
				 "with an internal log\n"));
			return 0;
		}
	} else {
		if (!x.logdev || (x.logdev == x.ddev)) {
			dbprintf(_("aborting - no external log specified for FS "
				 "with an external log\n"));
			return 0;
		}
	}

	libxfs_buftarg_init(mp, x.ddev, x.logdev, x.rtdev);

	dirty = xlog_is_dirty(mp, mp->m_log, &x, 0);
	if (dirty == -1) {
		dbprintf(_("ERROR: cannot find log head/tail, run xfs_repair\n"));
		return 0;
	} else if (dirty == 1) {
		dbprintf(_(
"ERROR: The filesystem has valuable metadata changes in a log which needs to\n"
"be replayed.  Mount the filesystem to replay the log, and unmount it before\n"
"re-running %s.  If you are unable to mount the filesystem, then use\n"
"the xfs_repair -L option to destroy the log and attempt a repair.\n"
"Note that destroying the log may cause corruption -- please attempt a mount\n"
"of the filesystem before doing this.\n"), progname);
		return 0;
	}
	/* Log is clean */
	return 1;
}

static int
sb_logzero(uuid_t *uuidp)
{
	int	cycle = XLOG_INIT_CYCLE;
	int	error;

	if (!sb_logcheck())
		return 0;

	/*
	 * The log must always move forward on v5 superblocks. Bump it to the
	 * next cycle.
	 */
	if (xfs_sb_version_hascrc(&mp->m_sb))
		cycle = mp->m_log->l_curr_cycle + 1;

	dbprintf(_("Clearing log and setting UUID\n"));

	error =  libxfs_log_clear(mp->m_logdev_targp, NULL,
			XFS_FSB_TO_DADDR(mp, mp->m_sb.sb_logstart),
			(xfs_extlen_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks),
			uuidp,
			xfs_sb_version_haslogv2(&mp->m_sb) ? 2 : 1,
			mp->m_sb.sb_logsunit, XLOG_FMT, cycle, true);
	if (error) {
		dbprintf(_("ERROR: cannot clear the log\n"));
		return 0;
	}

	return 1;
}


static void
uuid_help(void)
{
	dbprintf(_(
"\n"
" write/print FS uuid\n"
"\n"
" Example:\n"
"\n"
" 'uuid'                                      - print UUID\n"
" 'uuid 01234567-0123-0123-0123-0123456789ab' - write UUID\n"
" 'uuid generate'                             - generate and write\n"
" 'uuid rewrite'                              - copy UUID from SB 0\n"
"\n"
"The print function checks the UUID in each SB and will warn if the UUIDs\n"
"differ between AGs (the log is not checked). The write commands will\n"
"set the uuid in all AGs to either a specified value, a newly generated\n"
"value or the value found in the first superblock (SB 0) respectively.\n"
"As a side effect of writing the UUID, the log is cleared (which is fine\n"
"on a CLEANLY unmounted FS).\n"
"\n"
));
}

static uuid_t *
do_uuid(xfs_agnumber_t agno, uuid_t *uuid)
{
	xfs_sb_t	tsb;
	static uuid_t	uu;

	if (!get_sb(agno, &tsb))
		return NULL;

	if (!uuid) {	/* get uuid */
		memcpy(&uu, &tsb.sb_uuid, sizeof(uuid_t));
		pop_cur();
		return &uu;
	}
	/* set uuid */
	if (!xfs_sb_version_hascrc(&tsb))
		goto write;
	/*
	 * If we have CRCs, and this UUID differs from that stamped in the
	 * metadata, set the incompat flag and copy the old one to the
	 * metadata-specific location.
	 *
	 * If we are setting the user-visible UUID back to match the metadata
	 * UUID, clear the metadata-specific location and the incompat flag.
	 */
	if (!xfs_sb_version_hasmetauuid(&tsb) &&
	    !uuid_equal(uuid, &mp->m_sb.sb_meta_uuid)) {
		mp->m_sb.sb_features_incompat |= XFS_SB_FEAT_INCOMPAT_META_UUID;
		tsb.sb_features_incompat |= XFS_SB_FEAT_INCOMPAT_META_UUID;
		memcpy(&tsb.sb_meta_uuid, &tsb.sb_uuid, sizeof(uuid_t));
	} else if (xfs_sb_version_hasmetauuid(&tsb) &&
		   uuid_equal(uuid, &mp->m_sb.sb_meta_uuid)) {
		memset(&tsb.sb_meta_uuid, 0, sizeof(uuid_t));
		/* Write those zeros now; it's ignored once we clear the flag */
		libxfs_sb_to_disk(iocur_top->data, &tsb);
		mp->m_sb.sb_features_incompat &=
						~XFS_SB_FEAT_INCOMPAT_META_UUID;
		tsb.sb_features_incompat &= ~XFS_SB_FEAT_INCOMPAT_META_UUID;
	}

write:
	memcpy(&tsb.sb_uuid, uuid, sizeof(uuid_t));
	libxfs_sb_to_disk(iocur_top->data, &tsb);
	write_cur();
	return uuid;
}

static int
uuid_f(
	int		argc,
	char		**argv)
{
	char	        bp[40];
	xfs_agnumber_t	agno;
	uuid_t		uu;
	uuid_t		*uup = NULL;

	if (argc != 1 && argc != 2) {
		dbprintf(_("invalid parameters\n"));
		return 0;
	}

	if (argc == 2) {	/* WRITE UUID */

		if ((x.isreadonly & LIBXFS_ISREADONLY) || !expert_mode) {
			dbprintf(_("%s: not in expert mode, writing disabled\n"),
				progname);
			return 0;
		}

		if (!strcasecmp(argv[1], "generate")) {
			platform_uuid_generate(&uu);
		} else if (!strcasecmp(argv[1], "nil")) {
			platform_uuid_clear(&uu);
		} else if (!strcasecmp(argv[1], "rewrite")) {
			uup = do_uuid(0, NULL);
			if (!uup) {
				dbprintf(_("failed to read UUID from AG 0\n"));
				return 0;
			}
			memcpy(&uu, uup, sizeof(uuid_t));
			platform_uuid_unparse(&uu, bp);
			dbprintf(_("old UUID = %s\n"), bp);
		} else if (!strcasecmp(argv[1], "restore")) {
			xfs_sb_t	tsb;

			if (!get_sb(0, &tsb))
				return 0;

			/* Not set; nothing to do.  Success! */
			if (!xfs_sb_version_hasmetauuid(&tsb))
				return 0;

			memcpy(&uu, mp->m_sb.sb_meta_uuid, sizeof(uuid_t));
		} else {
			if (platform_uuid_parse(argv[1], &uu)) {
				dbprintf(_("invalid UUID\n"));
				return 0;
			}
		}

		/* clear the log (setting uuid) if it's not dirty */
		if (!sb_logzero(&uu))
			return 0;

		dbprintf(_("writing all SBs\n"));
		for (agno = 0; agno < mp->m_sb.sb_agcount; agno++)
			if (!do_uuid(agno, &uu)) {
				dbprintf(_("failed to set UUID in AG %d\n"), agno);
				break;
			}

		platform_uuid_unparse(&uu, bp);
		dbprintf(_("new UUID = %s\n"), bp);
		return 0;

	} else {	/* READ+CHECK UUID */

		for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
			uup = do_uuid(agno, NULL);
			if (!uup) {
				dbprintf(_("failed to read UUID from AG %d\n"),
					agno);
				return 0;
			}
			if (agno) {
				if (memcmp(&uu, uup, sizeof(uuid_t))) {
					dbprintf(_("warning: UUID in AG %d "
						 "differs to the primary SB\n"),
						agno);
					break;
				}
			} else {
				memcpy(&uu, uup, sizeof(uuid_t));
			}
		}
		if (mp->m_sb.sb_logstart) {
			if (x.logdev && x.logdev != x.ddev)
				dbprintf(_("warning - external log specified "
					 "for FS with an internal log\n"));
		} else if (!x.logdev || (x.logdev == x.ddev)) {
			dbprintf(_("warning - no external log specified "
				 "for FS with an external log\n"));
		}

		platform_uuid_unparse(&uu, bp);
		dbprintf(_("UUID = %s\n"), bp);
	}

	return 0;
}


static void
label_help(void)
{
	dbprintf(_(
"\n"
" write/print FS label\n"
"\n"
" Example:\n"
"\n"
" 'label'              - print label\n"
" 'label 123456789012' - write label\n"
" 'label --'           - write an empty label\n"
"\n"
"The print function checks the label in each SB and will warn if the labels\n"
"differ between AGs. The write commands will set the label in all AGs to the\n"
"specified value.  The maximum length of a label is 12 characters - use of a\n"
"longer label will result in truncation and a warning will be issued.\n"
"\n"
));
}

static char *
do_label(xfs_agnumber_t agno, char *label)
{
	size_t		len;
	xfs_sb_t	tsb;
	static char	lbl[sizeof(tsb.sb_fname) + 1];

	if (!get_sb(agno, &tsb))
		return NULL;

	memset(&lbl[0], 0, sizeof(lbl));

	if (!label) {	/* get label */
		pop_cur();
		memcpy(&lbl[0], &tsb.sb_fname, sizeof(tsb.sb_fname));
		return &lbl[0];
	}
	/* set label */
	if ((len = strlen(label)) > sizeof(tsb.sb_fname)) {
		if (agno == 0)
			dbprintf(_("%s: truncating label length from %d to %d\n"),
				progname, (int)len, (int)sizeof(tsb.sb_fname));
		len = sizeof(tsb.sb_fname);
	}
	if ( len == 2 &&
	     (strcmp(label, "\"\"") == 0 ||
	      strcmp(label, "''")   == 0 ||
	      strcmp(label, "--")   == 0) )
		label[0] = label[1] = '\0';
	memset(&tsb.sb_fname, 0, sizeof(tsb.sb_fname));
	memcpy(&tsb.sb_fname, label, len);
	memcpy(&lbl[0], &tsb.sb_fname, sizeof(tsb.sb_fname));
	libxfs_sb_to_disk(iocur_top->data, &tsb);
	write_cur();
	return &lbl[0];
}

static int
label_f(
	int		argc,
	char		**argv)
{
	char		*p = NULL;
	xfs_sb_t	sb;
	xfs_agnumber_t	ag;

	if (argc != 1 && argc != 2) {
		dbprintf(_("invalid parameters\n"));
		return 0;
	}

	if (argc == 2) {	/* WRITE LABEL */

		if ((x.isreadonly & LIBXFS_ISREADONLY) || !expert_mode) {
			dbprintf(_("%s: not in expert mode, writing disabled\n"),
				progname);
			return 0;
		}

		dbprintf(_("writing all SBs\n"));
		for (ag = 0; ag < mp->m_sb.sb_agcount; ag++)
			if ((p = do_label(ag, argv[1])) == NULL) {
				dbprintf(_("failed to set label in AG %d\n"), ag);
				break;
			}
		dbprintf(_("new label = \"%s\"\n"), p);

	} else {	/* READ LABEL */

		for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
			p = do_label(ag, NULL);
			if (!p) {
				dbprintf(_("failed to read label in AG %d\n"), ag);
				return 0;
			}
			if (!ag)
				memcpy(&sb.sb_fname, p, sizeof(sb.sb_fname));
			else if (memcmp(&sb.sb_fname, p, sizeof(sb.sb_fname)))
				dbprintf(_("warning: AG %d label differs\n"), ag);
		}
		dbprintf(_("label = \"%s\"\n"), p);
	}
	return 0;
}


static void
version_help(void)
{
	dbprintf(_(
"\n"
" set/print feature bits in sb version\n"
"\n"
" Example:\n"
"\n"
" 'version'          - print current feature bits\n"
" 'version extflg'   - enable unwritten extents\n"
" 'version attr1'    - enable v1 inline extended attributes\n"
" 'version attr2'    - enable v2 inline extended attributes\n"
" 'version log2'     - enable v2 log format\n"
"\n"
"The version function prints currently enabled features for a filesystem\n"
"according to the version field of its primary superblock.\n"
"It can also be used to enable selected features, such as support for\n"
"unwritten extents.  The updated version is written into all AGs.\n"
"\n"
));
}

static int
do_version(xfs_agnumber_t agno, uint16_t version, uint32_t features)
{
	xfs_sb_t	tsb;

	if (!get_sb(agno, &tsb))
		return 0;

	if (xfs_sb_has_mismatched_features2(&tsb)) {
		dbprintf(_("Superblock has mismatched features2 fields, "
			   "skipping modification\n"));
		return 0;
	}

	if ((version & XFS_SB_VERSION_LOGV2BIT) &&
					!xfs_sb_version_haslogv2(&tsb)) {
		tsb.sb_logsunit = 1;
	}

	tsb.sb_versionnum = version;
	tsb.sb_features2 = features;
	tsb.sb_bad_features2 = features;
	libxfs_sb_to_disk(iocur_top->data, &tsb);
	write_cur();
	return 1;
}

static char *
version_string(
	xfs_sb_t	*sbp)
{
	static char	s[1024];

	if (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_1)
		strcpy(s, "V1");
	else if (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_2)
		strcpy(s, "V2");
	else if (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_3)
		strcpy(s, "V3");
	else if (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4)
		strcpy(s, "V4");
	else if (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5)
		strcpy(s, "V5");

	/*
	 * We assume the state of these features now, so macros don't exist for
	 * them any more.
	 */
	if (sbp->sb_versionnum & XFS_SB_VERSION_NLINKBIT)
		strcat(s, ",NLINK");
	if (sbp->sb_versionnum & XFS_SB_VERSION_SHAREDBIT)
		strcat(s, ",SHARED");
	if (sbp->sb_versionnum & XFS_SB_VERSION_DIRV2BIT)
		strcat(s, ",DIRV2");

	if (xfs_sb_version_hasattr(sbp))
		strcat(s, ",ATTR");
	if (xfs_sb_version_hasquota(sbp))
		strcat(s, ",QUOTA");
	if (xfs_sb_version_hasalign(sbp))
		strcat(s, ",ALIGN");
	if (xfs_sb_version_hasdalign(sbp))
		strcat(s, ",DALIGN");
	if (xfs_sb_version_haslogv2(sbp))
		strcat(s, ",LOGV2");
	/* This feature is required now as well */
	if (sbp->sb_versionnum & XFS_SB_VERSION_EXTFLGBIT)
		strcat(s, ",EXTFLG");
	if (xfs_sb_version_hassector(sbp))
		strcat(s, ",SECTOR");
	if (xfs_sb_version_hasasciici(sbp))
		strcat(s, ",ASCII_CI");
	if (xfs_sb_version_hasmorebits(sbp))
		strcat(s, ",MOREBITS");
	if (xfs_sb_version_hasattr2(sbp))
		strcat(s, ",ATTR2");
	if (xfs_sb_version_haslazysbcount(sbp))
		strcat(s, ",LAZYSBCOUNT");
	if (xfs_sb_version_hasprojid32bit(sbp))
		strcat(s, ",PROJID32BIT");
	if (xfs_sb_version_hascrc(sbp))
		strcat(s, ",CRC");
	if (xfs_sb_version_hasftype(sbp))
		strcat(s, ",FTYPE");
	if (xfs_sb_version_hasfinobt(sbp))
		strcat(s, ",FINOBT");
	if (xfs_sb_version_hassparseinodes(sbp))
		strcat(s, ",SPARSE_INODES");
	if (xfs_sb_version_hasmetauuid(sbp))
		strcat(s, ",META_UUID");
	if (xfs_sb_version_hasrmapbt(sbp))
		strcat(s, ",RMAPBT");
	if (xfs_sb_version_hasreflink(sbp))
		strcat(s, ",REFLINK");
	return s;
}

/*
 * XXX: this only supports reading and writing to version 4 superblock fields.
 * V5 superblocks always define certain V4 feature bits - they are blocked from
 * being changed if a V5 sb is detected, but otherwise v5 superblock features
 * are not handled here.
 */
static int
version_f(
	int		argc,
	char		**argv)
{
	uint16_t	version = 0;
	uint32_t	features = 0;
	xfs_agnumber_t	ag;

	if (argc == 2) {	/* WRITE VERSION */

		if ((x.isreadonly & LIBXFS_ISREADONLY) || !expert_mode) {
			dbprintf(_("%s: not in expert mode, writing disabled\n"),
				progname);
			return 0;
		}

		/* Logic here derived from the IRIX xfs_chver(1M) script. */
		if (!strcasecmp(argv[1], "extflg")) {
			switch (XFS_SB_VERSION_NUM(&mp->m_sb)) {
			case XFS_SB_VERSION_1:
				version = 0x0004 | XFS_SB_VERSION_EXTFLGBIT;
				break;
			case XFS_SB_VERSION_2:
				version = 0x0014 | XFS_SB_VERSION_EXTFLGBIT;
				break;
			case XFS_SB_VERSION_3:
				version = 0x0034 | XFS_SB_VERSION_EXTFLGBIT;
				break;
			case XFS_SB_VERSION_4:
				if (mp->m_sb.sb_versionnum &
						XFS_SB_VERSION_EXTFLGBIT)
					dbprintf(
		_("unwritten extents flag is already enabled\n"));
				else
					version = mp->m_sb.sb_versionnum |
						  XFS_SB_VERSION_EXTFLGBIT;
				break;
			case XFS_SB_VERSION_5:
				dbprintf(
		_("unwritten extents always enabled for v5 superblocks.\n"));
				break;
			}
		} else if (!strcasecmp(argv[1], "log2")) {
			switch (XFS_SB_VERSION_NUM(&mp->m_sb)) {
			case XFS_SB_VERSION_1:
				version = 0x0004 | XFS_SB_VERSION_LOGV2BIT;
				break;
			case XFS_SB_VERSION_2:
				version = 0x0014 | XFS_SB_VERSION_LOGV2BIT;
				break;
			case XFS_SB_VERSION_3:
				version = 0x0034 | XFS_SB_VERSION_LOGV2BIT;
				break;
			case XFS_SB_VERSION_4:
				if (xfs_sb_version_haslogv2(&mp->m_sb))
					dbprintf(
		_("version 2 log format is already in use\n"));
				else
					version = mp->m_sb.sb_versionnum |
						  XFS_SB_VERSION_LOGV2BIT;
				break;
			case XFS_SB_VERSION_5:
				dbprintf(
		_("Version 2 logs always enabled for v5 superblocks.\n"));
				break;
			}
		} else if (XFS_SB_VERSION_NUM(&mp->m_sb) == XFS_SB_VERSION_5) {
			dbprintf(
		_("%s: Cannot change %s on v5 superblocks.\n"),
				progname, argv[1]);
			return 0;
		} else if (!strcasecmp(argv[1], "attr1")) {

			if (xfs_sb_version_hasattr2(&mp->m_sb)) {
				if (!(mp->m_sb.sb_features2 &=
						~XFS_SB_VERSION2_ATTR2BIT))
					mp->m_sb.sb_versionnum &=
						~XFS_SB_VERSION_MOREBITSBIT;
			}
			xfs_sb_version_addattr(&mp->m_sb);
			version = mp->m_sb.sb_versionnum;
			features = mp->m_sb.sb_features2;
		} else if (!strcasecmp(argv[1], "attr2")) {
			xfs_sb_version_addattr(&mp->m_sb);
			xfs_sb_version_addattr2(&mp->m_sb);
			version = mp->m_sb.sb_versionnum;
			features = mp->m_sb.sb_features2;
		} else if (!strcasecmp(argv[1], "projid32bit")) {
			xfs_sb_version_addprojid32bit(&mp->m_sb);
			version = mp->m_sb.sb_versionnum;
			features = mp->m_sb.sb_features2;
		} else {
			dbprintf(_("%s: invalid version change command \"%s\"\n"),
				progname, argv[1]);
			return 0;
		}

		if (version) {
			dbprintf(_("writing all SBs\n"));
			for (ag = 0; ag < mp->m_sb.sb_agcount; ag++)
				if (!do_version(ag, version, features)) {
					dbprintf(_("failed to set versionnum "
						 "in AG %d\n"), ag);
					break;
				}
			mp->m_sb.sb_versionnum = version;
			mp->m_sb.sb_features2 = features;
		}
	}

	if (argc == 3) {	/* VERSIONNUM + FEATURES2 */
		char	*sp;

		version = mp->m_sb.sb_versionnum;
		features = mp->m_sb.sb_features2;
		mp->m_sb.sb_versionnum = strtoul(argv[1], &sp, 0);
		mp->m_sb.sb_features2 = strtoul(argv[2], &sp, 0);
	}

	dbprintf(_("versionnum [0x%x+0x%x] = %s\n"), mp->m_sb.sb_versionnum,
			mp->m_sb.sb_features2, version_string(&mp->m_sb));

	if (argc == 3) {	/* now reset... */
		mp->m_sb.sb_versionnum = version;
		mp->m_sb.sb_features2 = features;
		return 0;
	}

	return 0;
}