[thirdparty/xfsprogs-dev.git] / repair / xfs_repair.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 */

#include "libxfs.h"
#include "libxlog.h"
#include <sys/resource.h>
#include "xfs_multidisk.h"
#include "avl.h"
#include "libfrog/avl64.h"
#include "globals.h"
#include "versions.h"
#include "agheader.h"
#include "protos.h"
#include "incore.h"
#include "err_protos.h"
#include "prefetch.h"
#include "threads.h"
#include "progress.h"
#include "dinode.h"
#include "slab.h"
#include "rmap.h"
#include "libfrog/fsgeom.h"
#include "libfrog/platform.h"

/*
 * option tables for getsubopt calls
 */

/*
 * -o: user-supplied override options
 */
enum o_opt_nums {
        ASSUME_XFS = 0,
        IHASH_SIZE,
        BHASH_SIZE,
        AG_STRIDE,
        FORCE_GEO,
        PHASE2_THREADS,
        O_MAX_OPTS,
};

static char *o_opts[] = {
        [ASSUME_XFS]            = "assume_xfs",
        [IHASH_SIZE]            = "ihash",
        [BHASH_SIZE]            = "bhash",
        [AG_STRIDE]             = "ag_stride",
        [FORCE_GEO]             = "force_geometry",
        [PHASE2_THREADS]        = "phase2_threads",
        [O_MAX_OPTS]            = NULL,
};

/*
 * -c: conversion options
 */
enum c_opt_nums {
        CONVERT_LAZY_COUNT = 0,
        C_MAX_OPTS,
};

static char *c_opts[] = {
        [CONVERT_LAZY_COUNT]    = "lazycount",
        [C_MAX_OPTS]            = NULL,
};


static int      bhash_option_used;
static long     max_mem_specified;      /* in megabytes */
static int      phase2_threads = 32;
static bool     report_corrected;

static void
usage(void)
{
        do_warn(_(
"Usage: %s [options] device\n"
"\n"
"Options:\n"
"  -f           The device is a file\n"
"  -L           Force log zeroing. Do this as a last resort.\n"
"  -l logdev    Specifies the device where the external log resides.\n"
"  -m maxmem    Maximum amount of memory to be used in megabytes.\n"
"  -n           No modify mode, just checks the filesystem for damage.\n"
"               (Cannot be used together with -e.)\n"
"  -P           Disables prefetching.\n"
"  -r rtdev     Specifies the device where the realtime section resides.\n"
"  -v           Verbose output.\n"
"  -c subopts   Change filesystem parameters - use xfs_admin.\n"
"  -o subopts   Override default behaviour, refer to man page.\n"
"  -t interval  Reporting interval in seconds.\n"
"  -d           Repair dangerously.\n"
"  -e           Exit with a non-zero code if any errors were repaired.\n"
"               (Cannot be used together with -n.)\n"
"  -V           Reports version and exits.\n"), progname);
        exit(1);
}

char *
err_string(int err_code)
{
        static char *err_message[XR_BAD_ERR_CODE];
        static int done;

        if (!done) {
                err_message[XR_OK] = _("no error");
                err_message[XR_BAD_MAGIC] = _("bad magic number");
                err_message[XR_BAD_BLOCKSIZE] = _("bad blocksize field");
                err_message[XR_BAD_BLOCKLOG] = _("bad blocksize log field");
                err_message[XR_BAD_VERSION] = _("bad or unsupported version");
                err_message[XR_BAD_INPROGRESS] =
                        _("filesystem mkfs-in-progress bit set");
                err_message[XR_BAD_FS_SIZE_DATA] =
                        _("inconsistent filesystem geometry information");
                err_message[XR_BAD_INO_SIZE_DATA] =
        _("bad inode size or inconsistent with number of inodes/block"),
                err_message[XR_BAD_SECT_SIZE_DATA] = _("bad sector size");
                err_message[XR_AGF_GEO_MISMATCH] =
        _("AGF geometry info conflicts with filesystem geometry");
                err_message[XR_AGI_GEO_MISMATCH] =
        _("AGI geometry info conflicts with filesystem geometry");
                err_message[XR_SB_GEO_MISMATCH] =
        _("AG superblock geometry info conflicts with filesystem geometry");
                err_message[XR_EOF] = _("attempted to perform I/O beyond EOF");
                err_message[XR_BAD_RT_GEO_DATA] =
        _("inconsistent filesystem geometry in realtime filesystem component");
                err_message[XR_BAD_INO_MAX_PCT] =
                        _("maximum indicated percentage of inodes > 100%");
                err_message[XR_BAD_INO_ALIGN] =
                        _("inconsistent inode alignment value");
                err_message[XR_INSUFF_SEC_SB] =
        _("not enough secondary superblocks with matching geometry");
                err_message[XR_BAD_SB_UNIT] =
                        _("bad stripe unit in superblock");
                err_message[XR_BAD_SB_WIDTH] =
                        _("bad stripe width in superblock");
                err_message[XR_BAD_SVN] =
                        _("bad shared version number in superblock");
                err_message[XR_BAD_CRC] =
                        _("bad CRC in superblock");
                err_message[XR_BAD_DIR_SIZE_DATA] =
                        _("inconsistent directory geometry information");
                err_message[XR_BAD_LOG_GEOMETRY] =
                        _("inconsistent log geometry information");
                done = 1;
        }

        if (err_code < XR_OK || err_code >= XR_BAD_ERR_CODE)
                do_abort(_("bad error code - %d\n"), err_code);

        return(err_message[err_code]);
}

static void
noval(char opt, char *tbl[], int idx)
{
        do_warn(_("-%c %s option cannot have a value\n"), opt, tbl[idx]);
        usage();
}

static void
respec(char opt, char *tbl[], int idx)
{
        do_warn("-%c ", opt);
        if (tbl)
                do_warn("%s ", tbl[idx]);
        do_warn(_("option respecified\n"));
        usage();
}

static void
unknown(char opt, char *s)
{
        do_warn(_("unknown option -%c %s\n"), opt, s);
        usage();
}

/*
 * sets only the global argument flags and variables
 */
static void
process_args(int argc, char **argv)
{
        char *p;
        int c;

        log_spec = 0;
        fs_is_dirty = 0;
        verbose = 0;
        no_modify = 0;
        dangerously = 0;
        isa_file = 0;
        zap_log = 0;
        dumpcore = 0;
        full_ino_ex_data = 0;
        force_geo = 0;
        assume_xfs = 0;
        copied_sunit = 0;
        sb_inoalignmt = 0;
        sb_unit = 0;
        sb_width = 0;
        ag_stride = 0;
        thread_count = 1;
        report_interval = PROG_RPT_DEFAULT;
        report_corrected = false;

        /*
         * XXX have to add suboption processing here
         * attributes, quotas, nlinks, aligned_inos, sb_fbits
         */
        while ((c = getopt(argc, argv, "c:o:fl:m:r:LnDvVdPet:")) != EOF)  {
                switch (c) {
                case 'D':
                        dumpcore = 1;
                        break;
                case 'o':
                        p = optarg;
                        while (*p != '\0')  {
                                char *val;

                                switch (getsubopt(&p, o_opts, &val))  {
                                case ASSUME_XFS:
                                        if (val)
                                                noval('o', o_opts, ASSUME_XFS);
                                        if (assume_xfs)
                                                respec('o', o_opts, ASSUME_XFS);
                                        assume_xfs = 1;
                                        break;
                                case IHASH_SIZE:
                                        do_warn(
                _("-o ihash option has been removed and will be ignored\n"));
                                        break;
                                case BHASH_SIZE:
                                        if (max_mem_specified)
                                                do_abort(
                _("-o bhash option cannot be used with -m option\n"));
                                        if (!val)
                                                do_abort(
                _("-o bhash requires a parameter\n"));
                                        libxfs_bhash_size = (int)strtol(val, NULL, 0);
                                        bhash_option_used = 1;
                                        break;
                                case AG_STRIDE:
                                        if (!val)
                                                do_abort(
                _("-o ag_stride requires a parameter\n"));
                                        ag_stride = (int)strtol(val, NULL, 0);
                                        break;
                                case FORCE_GEO:
                                        if (val)
                                                noval('o', o_opts, FORCE_GEO);
                                        if (force_geo)
                                                respec('o', o_opts, FORCE_GEO);
                                        force_geo = 1;
                                        break;
                                case PHASE2_THREADS:
                                        if (!val)
                                                do_abort(
                _("-o phase2_threads requires a parameter\n"));
                                        phase2_threads = (int)strtol(val, NULL, 0);
                                        break;
                                default:
                                        unknown('o', val);
                                        break;
                                }
                        }
                        break;
                case 'c':
                        p = optarg;
                        while (*p) {
                                char *val;

                                switch (getsubopt(&p, c_opts, &val)) {
                                case CONVERT_LAZY_COUNT:
                                        if (!val)
                                                do_abort(
                _("-c lazycount requires a parameter\n"));
                                        lazy_count = (int)strtol(val, NULL, 0);
                                        convert_lazy_count = 1;
                                        break;
                                default:
                                        unknown('c', val);
                                        break;
                                }
                        }
                        break;
                case 'l':
                        log_name = optarg;
                        log_spec = 1;
                        break;
                case 'r':
                        rt_name = optarg;
                        rt_spec = 1;
                        break;
                case 'f':
                        isa_file = 1;
                        break;
                case 'm':
                        if (bhash_option_used)
                                do_abort(_("-m option cannot be used with "
                                                "-o bhash option\n"));
                        max_mem_specified = strtol(optarg, NULL, 0);
                        break;
                case 'L':
                        zap_log = 1;
                        break;
                case 'n':
                        no_modify = 1;
                        break;
                case 'd':
                        dangerously = 1;
                        break;
                case 'v':
                        verbose++;
                        break;
                case 'V':
                        printf(_("%s version %s\n"), progname, VERSION);
                        exit(0);
                case 'P':
                        do_prefetch = 0;
                        break;
                case 't':
                        report_interval = (int)strtol(optarg, NULL, 0);
                        break;
                case 'e':
                        report_corrected = true;
                        break;
                case '?':
                        usage();
                }
        }

        if (argc - optind != 1)
                usage();

        if ((fs_name = argv[optind]) == NULL)
                usage();

        if (report_corrected && no_modify)
                usage();
}

void __attribute__((noreturn))
do_error(char const *msg, ...)
{
        va_list args;

        fprintf(stderr, _("\nfatal error -- "));

        va_start(args, msg);
        vfprintf(stderr, msg, args);
        if (dumpcore)
                abort();
        exit(1);
}

/*
 * like do_error, only the error is internal, no system
 * error so no oserror processing
 */
void __attribute__((noreturn))
do_abort(char const *msg, ...)
{
        va_list args;

        va_start(args, msg);
        vfprintf(stderr, msg, args);
        if (dumpcore)
                abort();
        exit(1);
}

void
do_warn(char const *msg, ...)
{
        va_list args;

        fs_is_dirty = 1;

        va_start(args, msg);
        vfprintf(stderr, msg, args);
        va_end(args);
}

/* no formatting */

void
do_log(char const *msg, ...)
{
        va_list args;

        va_start(args, msg);
        vfprintf(stderr, msg, args);
        va_end(args);
}

static void
calc_mkfs(xfs_mount_t *mp)
{
        xfs_agblock_t   fino_bno;
        int             do_inoalign;

        do_inoalign = M_IGEO(mp)->ialloc_align;

        /*
         * Pre-calculate the geometry of ag 0. We know what it looks like
         * because we know what mkfs does: 2 allocation btree roots (by block
         * and by size), the inode allocation btree root, the free inode
         * allocation btree root (if enabled) and some number of blocks to
         * prefill the agfl.
         *
         * Because the current shape of the btrees may differ from the current
         * shape, we open code the mkfs freelist block count here. mkfs creates
         * single level trees, so the calculation is pertty straight forward for
         * the trees that use the AGFL.
         */
        bnobt_root = howmany(4 * mp->m_sb.sb_sectsize, mp->m_sb.sb_blocksize);
        bcntbt_root = bnobt_root + 1;
        inobt_root = bnobt_root + 2;
        fino_bno = inobt_root + (2 * min(2, mp->m_ag_maxlevels)) + 1;
        if (xfs_sb_version_hasfinobt(&mp->m_sb))
                fino_bno++;
        if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
                fino_bno += min(2, mp->m_rmap_maxlevels); /* agfl blocks */
                fino_bno++;
        }
        if (xfs_sb_version_hasreflink(&mp->m_sb))
                fino_bno++;

        /*
         * If the log is allocated in the first allocation group we need to
         * add the number of blocks used by the log to the above calculation.
         *
         * This can happens with filesystems that only have a single
         * allocation group, or very odd geometries created by old mkfs
         * versions on very small filesystems.
         */
        if (mp->m_sb.sb_logstart &&
            XFS_FSB_TO_AGNO(mp, mp->m_sb.sb_logstart) == 0) {

                /*
                 * XXX(hch): verify that sb_logstart makes sense?
                 */
                 fino_bno += mp->m_sb.sb_logblocks;
        }

        /*
         * ditto the location of the first inode chunks in the fs ('/')
         */
        if (xfs_sb_version_hasdalign(&mp->m_sb) && do_inoalign)  {
                first_prealloc_ino = XFS_AGB_TO_AGINO(mp, roundup(fino_bno,
                                        mp->m_sb.sb_unit));
        } else if (xfs_sb_version_hasalign(&mp->m_sb) &&
                                        mp->m_sb.sb_inoalignmt > 1)  {
                first_prealloc_ino = XFS_AGB_TO_AGINO(mp,
                                        roundup(fino_bno,
                                                mp->m_sb.sb_inoalignmt));
        } else  {
                first_prealloc_ino = XFS_AGB_TO_AGINO(mp, fino_bno);
        }

        ASSERT(M_IGEO(mp)->ialloc_blks > 0);

        if (M_IGEO(mp)->ialloc_blks > 1)
                last_prealloc_ino = first_prealloc_ino + XFS_INODES_PER_CHUNK;
        else
                last_prealloc_ino = XFS_AGB_TO_AGINO(mp, fino_bno + 1);

        /*
         * now the first 3 inodes in the system
         */
        if (mp->m_sb.sb_rootino != first_prealloc_ino)  {
                do_warn(
_("sb root inode value %" PRIu64 " %sinconsistent with calculated value %u\n"),
                        mp->m_sb.sb_rootino,
                        (mp->m_sb.sb_rootino == NULLFSINO ? "(NULLFSINO) ":""),
                        first_prealloc_ino);

                if (!no_modify)
                        do_warn(
                _("resetting superblock root inode pointer to %u\n"),
                                first_prealloc_ino);
                else
                        do_warn(
                _("would reset superblock root inode pointer to %u\n"),
                                first_prealloc_ino);

                /*
                 * just set the value -- safe since the superblock
                 * doesn't get flushed out if no_modify is set
                 */
                mp->m_sb.sb_rootino = first_prealloc_ino;
        }

        if (mp->m_sb.sb_rbmino != first_prealloc_ino + 1)  {
                do_warn(
_("sb realtime bitmap inode %" PRIu64 " %sinconsistent with calculated value %u\n"),
                        mp->m_sb.sb_rbmino,
                        (mp->m_sb.sb_rbmino == NULLFSINO ? "(NULLFSINO) ":""),
                        first_prealloc_ino + 1);

                if (!no_modify)
                        do_warn(
                _("resetting superblock realtime bitmap ino pointer to %u\n"),
                                first_prealloc_ino + 1);
                else
                        do_warn(
                _("would reset superblock realtime bitmap ino pointer to %u\n"),
                                first_prealloc_ino + 1);

                /*
                 * just set the value -- safe since the superblock
                 * doesn't get flushed out if no_modify is set
                 */
                mp->m_sb.sb_rbmino = first_prealloc_ino + 1;
        }

        if (mp->m_sb.sb_rsumino != first_prealloc_ino + 2)  {
                do_warn(
_("sb realtime summary inode %" PRIu64 " %sinconsistent with calculated value %u\n"),
                        mp->m_sb.sb_rsumino,
                        (mp->m_sb.sb_rsumino == NULLFSINO ? "(NULLFSINO) ":""),
                        first_prealloc_ino + 2);

                if (!no_modify)
                        do_warn(
                _("resetting superblock realtime summary ino pointer to %u\n"),
                                first_prealloc_ino + 2);
                else
                        do_warn(
                _("would reset superblock realtime summary ino pointer to %u\n"),
                                first_prealloc_ino + 2);

                /*
                 * just set the value -- safe since the superblock
                 * doesn't get flushed out if no_modify is set
                 */
                mp->m_sb.sb_rsumino = first_prealloc_ino + 2;
        }

}

/*
 * v5 superblock metadata track the LSN of last modification and thus require
 * that the current LSN is always moving forward. The current LSN is reset if
 * the log has been cleared, which puts the log behind parts of the filesystem
 * on-disk and can disrupt log recovery.
 *
 * We have tracked the maximum LSN of every piece of metadata that has been read
 * in via the read verifiers. Compare the max LSN with the log and if the log is
 * behind, bump the cycle number and reformat the log.
 */
static void
format_log_max_lsn(
        struct xfs_mount        *mp)
{
        struct xlog             *log = mp->m_log;
        int                     max_cycle;
        int                     max_block;
        int                     new_cycle;
        xfs_daddr_t             logstart;
        xfs_daddr_t             logblocks;
        int                     logversion;

        if (!xfs_sb_version_hascrc(&mp->m_sb))
                return;

        /*
         * If the log is ahead of the highest metadata LSN we've seen, we're
         * safe and there's nothing to do.
         */
        max_cycle = CYCLE_LSN(libxfs_max_lsn);
        max_block = BLOCK_LSN(libxfs_max_lsn);
        if (max_cycle < log->l_curr_cycle ||
            (max_cycle == log->l_curr_cycle && max_block < log->l_curr_block))
                return;

        /*
         * Going to the next cycle should be sufficient but we bump by a few
         * counts to help cover any metadata LSNs we could have missed.
         */
        new_cycle = max_cycle + 3;
        logstart = XFS_FSB_TO_DADDR(mp, mp->m_sb.sb_logstart);
        logblocks = XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
        logversion = xfs_sb_version_haslogv2(&mp->m_sb) ? 2 : 1;

        do_warn(_("Maximum metadata LSN (%d:%d) is ahead of log (%d:%d).\n"),
                max_cycle, max_block, log->l_curr_cycle, log->l_curr_block);

        if (no_modify) {
                do_warn(_("Would format log to cycle %d.\n"), new_cycle);
                return;
        }

        do_warn(_("Format log to cycle %d.\n"), new_cycle);
        libxfs_log_clear(log->l_dev, NULL, logstart, logblocks,
                         &mp->m_sb.sb_uuid, logversion, mp->m_sb.sb_logsunit,
                         XLOG_FMT, new_cycle, true);
}

/*
 * mkfs increases the AG count for "multidisk" configurations, we want
 * to target these for an increase in thread count. Hence check the superlock
 * geometry information to determine if mkfs considered this a multidisk
 * configuration.
 */
static bool
is_multidisk_filesystem(
        struct xfs_mount        *mp)
{
        struct xfs_sb           *sbp = &mp->m_sb;

        /* High agcount filesystems are always considered "multidisk" */
        if (sbp->sb_agcount >= XFS_MULTIDISK_AGCOUNT)
                return true;

        /*
         * If it doesn't have a sunit/swidth, mkfs didn't consider it a
         * multi-disk array, so we don't either.
         */
        if (!sbp->sb_unit)
                return false;

        ASSERT(sbp->sb_width);
        return true;
}

/*
 * if the sector size of the filesystem we are trying to repair is
 * smaller than that of the underlying filesystem (i.e. we are repairing
 * an image), the we have to turn off direct IO because we cannot do IO
 * smaller than the host filesystem's sector size.
 */
static void
check_fs_vs_host_sectsize(
        struct xfs_sb   *sb)
{
        int     fd, ret;
        long    old_flags;
        struct xfs_fsop_geom    geom = { 0 };

        fd = libxfs_device_to_fd(x.ddev);

        ret = xfrog_geometry(fd, &geom);
        if (ret) {
                do_log(_("Cannot get host filesystem geometry.\n"
        "Repair may fail if there is a sector size mismatch between\n"
        "the image and the host filesystem.\n"));
                geom.sectsize = BBSIZE;
        }

        if (sb->sb_sectsize < geom.sectsize) {
                old_flags = fcntl(fd, F_GETFL, 0);
                if (fcntl(fd, F_SETFL, old_flags & ~O_DIRECT) < 0) {
                        do_warn(_(
        "Sector size on host filesystem larger than image sector size.\n"
        "Cannot turn off direct IO, so exiting.\n"));
                        exit(1);
                }
        }
}

int
main(int argc, char **argv)
{
        xfs_mount_t     *temp_mp;
        xfs_mount_t     *mp;
        xfs_dsb_t       *dsb;
        xfs_buf_t       *sbp;
        xfs_mount_t     xfs_m;
        struct xlog     log = {0};
        char            *msgbuf;
        struct xfs_sb   psb;
        int             rval;
        struct xfs_ino_geometry *igeo;

        progname = basename(argv[0]);
        setlocale(LC_ALL, "");
        bindtextdomain(PACKAGE, LOCALEDIR);
        textdomain(PACKAGE);
        dinode_bmbt_translation_init();

        temp_mp = &xfs_m;
        setbuf(stdout, NULL);

        process_args(argc, argv);
        xfs_init(&x);

        msgbuf = malloc(DURATION_BUF_SIZE);

        timestamp(PHASE_START, 0, NULL);
        timestamp(PHASE_END, 0, NULL);

        /* -f forces this, but let's be nice and autodetect it, as well. */
        if (!isa_file) {
                int             fd = libxfs_device_to_fd(x.ddev);
                struct stat     statbuf;

                if (fstat(fd, &statbuf) < 0)
                        do_warn(_("%s: couldn't stat \"%s\"\n"),
                                progname, fs_name);
                else if (S_ISREG(statbuf.st_mode))
                        isa_file = 1;
        }

        if (isa_file) {
                /* Best effort attempt to validate fs vs host sector size */
                rval = get_sb(&psb, 0, XFS_MAX_SECTORSIZE, 0);
                if (rval == XR_OK)
                        check_fs_vs_host_sectsize(&psb);
        }

        /* do phase1 to make sure we have a superblock */
        phase1(temp_mp);
        timestamp(PHASE_END, 1, NULL);

        if (no_modify && primary_sb_modified)  {
                do_warn(_("Primary superblock would have been modified.\n"
                          "Cannot proceed further in no_modify mode.\n"
                          "Exiting now.\n"));
                exit(1);
        }

        rval = get_sb(&psb, 0, XFS_MAX_SECTORSIZE, 0);
        if (rval != XR_OK) {
                do_warn(_("Primary superblock bad after phase 1!\n"
                          "Exiting now.\n"));
                exit(1);
        }

        /*
         * Now that we have completely validated the superblock, geometry may
         * have changed; re-check geometry vs the host filesystem geometry
         */
        if (isa_file)
                check_fs_vs_host_sectsize(&psb);

        /*
         * Prepare the mount structure. Point the log reference to our local
         * copy so it's available to the various phases. The log bits are
         * initialized in phase 2.
         */
        memset(&xfs_m, 0, sizeof(xfs_mount_t));
        mp = libxfs_mount(&xfs_m, &psb, x.ddev, x.logdev, x.rtdev, 0);

        if (!mp)  {
                fprintf(stderr,
                        _("%s: cannot repair this filesystem.  Sorry.\n"),
                        progname);
                exit(1);
        }
        mp->m_log = &log;
        igeo = M_IGEO(mp);

        /* Spit out function & line on these corruption macros */
        if (verbose > 2)
                mp->m_flags |= LIBXFS_MOUNT_WANT_CORRUPTED;

        /*
         * set XFS-independent status vars from the mount/sb structure
         */
        glob_agcount = mp->m_sb.sb_agcount;

        chunks_pblock = mp->m_sb.sb_inopblock / XFS_INODES_PER_CHUNK;
        max_symlink_blocks = libxfs_symlink_blocks(mp, XFS_SYMLINK_MAXLEN);

        /*
         * Automatic striding for high agcount filesystems.
         *
         * More AGs indicates that the filesystem is either large or can handle
         * more IO parallelism. Either way, we should try to process multiple
         * AGs at a time in such a configuration to try to saturate the
         * underlying storage and speed the repair process. Only do this if
         * prefetching is enabled.
         *
         * Given mkfs defaults for 16AGs for "multidisk" configurations, we want
         * to target these for an increase in thread count. Hence a stride value
         * of 15 is chosen to ensure we get at least 2 AGs being scanned at once
         * on such filesystems.
         *
         * Limit the maximum thread count based on the available CPU power that
         * is available. If we use too many threads, we might run out of memory
         * and CPU power before we run out of IO concurrency. We limit to 8
         * threads/CPU as this is enough threads to saturate a CPU on fast
         * devices, yet few enough that it will saturate but won't overload slow
         * devices.
         *
         * Multidisk filesystems can handle more IO parallelism so we should try
         * to process multiple AGs at a time in such a configuration to try to
         * saturate the underlying storage and speed the repair process. Only do
         * this if prefetching is enabled.
         */
        if (!ag_stride && do_prefetch && is_multidisk_filesystem(mp)) {
                /*
                 * For small agcount multidisk systems, just double the
                 * parallelism. For larger AG count filesystems (32 and above)
                 * use more parallelism, and linearly increase the parallelism
                 * with the number of AGs.
                 */
                ag_stride = min(glob_agcount, XFS_MULTIDISK_AGCOUNT / 2) - 1;
        }

        if (ag_stride) {
                int max_threads = platform_nproc() * 8;

                thread_count = (glob_agcount + ag_stride - 1) / ag_stride;
                while (thread_count > max_threads) {
                        ag_stride *= 2;
                        thread_count = (glob_agcount + ag_stride - 1) /
                                                                ag_stride;
                }
                if (thread_count > 0)
                        thread_init();
                else {
                        thread_count = 1;
                        ag_stride = 0;
                }
        }

        if (ag_stride && report_interval) {
                init_progress_rpt();
                if (msgbuf) {
                        do_log(_("        - reporting progress in intervals of %s\n"),
                        duration(report_interval, msgbuf));
                }
        }

        /*
         * Adjust libxfs cache sizes based on system memory,
         * filesystem size and inode count.
         *
         * We'll set the cache size based on 3/4s the memory minus
         * space used by the inode AVL tree and block usage map.
         *
         * Inode AVL tree space is approximately 4 bytes per inode,
         * block usage map is currently 1 byte for 2 blocks.
         *
         * We assume most blocks will be inode clusters.
         *
         * Calculations are done in kilobyte units.
         */

        if (!bhash_option_used || max_mem_specified) {
                unsigned long   mem_used;
                unsigned long   max_mem;
                struct rlimit   rlim;

                libxfs_bcache_purge();
                cache_destroy(libxfs_bcache);

                mem_used = (mp->m_sb.sb_icount >> (10 - 2)) +
                                        (mp->m_sb.sb_dblocks >> (10 + 1)) +
                                        50000;  /* rough estimate of 50MB overhead */
                max_mem = max_mem_specified ? max_mem_specified * 1024 :
                                              platform_physmem() * 3 / 4;

                if (getrlimit(RLIMIT_AS, &rlim) != -1 &&
                                        rlim.rlim_cur != RLIM_INFINITY) {
                        rlim.rlim_cur = rlim.rlim_max;
                        setrlimit(RLIMIT_AS, &rlim);
                        /* use approximately 80% of rlimit to avoid overrun */
                        max_mem = min(max_mem, rlim.rlim_cur / 1280);
                } else
                        max_mem = min(max_mem, (LONG_MAX >> 10) + 1);

                if (verbose > 1)
                        do_log(
        _("        - max_mem = %lu, icount = %" PRIu64 ", imem = %" PRIu64 ", dblock = %" PRIu64 ", dmem = %" PRIu64 "\n"),
                                max_mem, mp->m_sb.sb_icount,
                                mp->m_sb.sb_icount >> (10 - 2),
                                mp->m_sb.sb_dblocks,
                                mp->m_sb.sb_dblocks >> (10 + 1));

                if (max_mem <= mem_used) {
                        if (max_mem_specified) {
                                do_abort(
        _("Required memory for repair is greater that the maximum specified\n"
          "with the -m option. Please increase it to at least %lu.\n"),
                                        mem_used / 1024);
                        }
                        do_log(
        _("Memory available for repair (%luMB) may not be sufficient.\n"
          "At least %luMB is needed to repair this filesystem efficiently\n"
          "If repair fails due to lack of memory, please\n"),
                                max_mem / 1024, mem_used / 1024);
                        if (do_prefetch)
                                do_log(
        _("turn prefetching off (-P) to reduce the memory footprint.\n"));
                        else
                                do_log(
        _("increase system RAM and/or swap space to at least %luMB.\n"),
                        mem_used * 2 / 1024);

                        max_mem = mem_used;
                }

                max_mem -= mem_used;
                if (max_mem >= (1 << 30))
                        max_mem = 1 << 30;
                libxfs_bhash_size = max_mem / (HASH_CACHE_RATIO *
                                (igeo->inode_cluster_size >> 10));
                if (libxfs_bhash_size < 512)
                        libxfs_bhash_size = 512;

                if (verbose)
                        do_log(_("        - block cache size set to %d entries\n"),
                                libxfs_bhash_size * HASH_CACHE_RATIO);

                libxfs_bcache = cache_init(0, libxfs_bhash_size,
                                                &libxfs_bcache_operations);
        }

        /*
         * calculate what mkfs would do to this filesystem
         */
        calc_mkfs(mp);

        /*
         * initialize block alloc map
         */
        init_bmaps(mp);
        incore_ino_init(mp);
        incore_ext_init(mp);
        rmaps_init(mp);

        /* initialize random globals now that we know the fs geometry */
        inodes_per_block = mp->m_sb.sb_inopblock;

        if (parse_sb_version(&mp->m_sb))  {
                do_warn(
        _("Found unsupported filesystem features.  Exiting now.\n"));
                return(1);
        }

        /* make sure the per-ag freespace maps are ok so we can mount the fs */
        phase2(mp, phase2_threads);
        timestamp(PHASE_END, 2, NULL);

        if (do_prefetch)
                init_prefetch(mp);

        phase3(mp, phase2_threads);
        timestamp(PHASE_END, 3, NULL);

        phase4(mp);
        timestamp(PHASE_END, 4, NULL);

        if (no_modify)
                printf(_("No modify flag set, skipping phase 5\n"));
        else {
                phase5(mp);
        }
        timestamp(PHASE_END, 5, NULL);

        /*
         * Done with the block usage maps, toss them...
         */
        rmaps_free(mp);
        free_bmaps(mp);

        if (!bad_ino_btree)  {
                phase6(mp);
                timestamp(PHASE_END, 6, NULL);

                phase7(mp, phase2_threads);
                timestamp(PHASE_END, 7, NULL);
        } else  {
                do_warn(
_("Inode allocation btrees are too corrupted, skipping phases 6 and 7\n"));
        }

        if (lost_quotas && !have_uquotino && !have_gquotino && !have_pquotino) {
                if (!no_modify)  {
                        do_warn(
_("Warning:  no quota inodes were found.  Quotas disabled.\n"));
                } else  {
                        do_warn(
_("Warning:  no quota inodes were found.  Quotas would be disabled.\n"));
                }
        } else if (lost_quotas)  {
                if (!no_modify)  {
                        do_warn(
_("Warning:  quota inodes were cleared.  Quotas disabled.\n"));
                } else  {
                        do_warn(
_("Warning:  quota inodes would be cleared.  Quotas would be disabled.\n"));
                }
        } else  {
                if (lost_uquotino)  {
                        if (!no_modify)  {
                                do_warn(
_("Warning:  user quota information was cleared.\n"
  "User quotas can not be enforced until limit information is recreated.\n"));
                        } else  {
                                do_warn(
_("Warning:  user quota information would be cleared.\n"
  "User quotas could not be enforced until limit information was recreated.\n"));
                        }
                }

                if (lost_gquotino)  {
                        if (!no_modify)  {
                                do_warn(
_("Warning:  group quota information was cleared.\n"
  "Group quotas can not be enforced until limit information is recreated.\n"));
                        } else  {
                                do_warn(
_("Warning:  group quota information would be cleared.\n"
  "Group quotas could not be enforced until limit information was recreated.\n"));
                        }
                }

                if (lost_pquotino)  {
                        if (!no_modify)  {
                                do_warn(
_("Warning:  project quota information was cleared.\n"
  "Project quotas can not be enforced until limit information is recreated.\n"));
                        } else  {
                                do_warn(
_("Warning:  project quota information would be cleared.\n"
  "Project quotas could not be enforced until limit information was recreated.\n"));
                        }
                }
        }

        if (ag_stride && report_interval)
                stop_progress_rpt();

        if (no_modify)  {
                /*
                 * Warn if the current LSN is problematic and the log requires a
                 * reformat.
                 */
                format_log_max_lsn(mp);

                do_log(
        _("No modify flag set, skipping filesystem flush and exiting.\n"));
                if (verbose)
                        summary_report();
                if (fs_is_dirty)
                        return(1);

                return(0);
        }

        /*
         * Clear the quota flags if they're on.
         */
        sbp = libxfs_getsb(mp);
        if (!sbp)
                do_error(_("couldn't get superblock\n"));

        dsb = XFS_BUF_TO_SBP(sbp);

        if (be16_to_cpu(dsb->sb_qflags) & XFS_ALL_QUOTA_CHKD) {
                do_warn(_("Note - quota info will be regenerated on next "
                        "quota mount.\n"));
                dsb->sb_qflags &= cpu_to_be16(~XFS_ALL_QUOTA_CHKD);
        }

        if (copied_sunit) {
                do_warn(
_("Note - stripe unit (%d) and width (%d) were copied from a backup superblock.\n"
  "Please reset with mount -o sunit=<value>,swidth=<value> if necessary\n"),
                        be32_to_cpu(dsb->sb_unit), be32_to_cpu(dsb->sb_width));
        }

        libxfs_writebuf(sbp, 0);

        /*
         * Done. Flush all cached buffers and inodes first to ensure all
         * verifiers are run (where we discover the max metadata LSN), reformat
         * the log if necessary and unmount.
         */
        libxfs_bcache_flush();
        format_log_max_lsn(mp);
        libxfs_umount(mp);

        if (x.rtdev)
                libxfs_device_close(x.rtdev);
        if (x.logdev && x.logdev != x.ddev)
                libxfs_device_close(x.logdev);
        libxfs_device_close(x.ddev);
        libxfs_destroy();

        if (verbose)
                summary_report();
        do_log(_("done\n"));

        if (dangerously && !no_modify)
                do_warn(
_("Repair of readonly mount complete.  Immediate reboot encouraged.\n"));

        pftrace_done();

        free(msgbuf);

        if (fs_is_dirty && report_corrected)
                return (4);
        return (0);
}