// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2017-2023 Oracle.  All Rights Reserved.
 * Author: Darrick J. Wong <djwong@kernel.org>
 */
#include "xfs_platform.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_bit.h"
#include "xfs_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_log_format.h"
#include "xfs_trans.h"
#include "xfs_inode.h"
#include "xfs_quota.h"
#include "xfs_qm.h"
#include "xfs_bmap.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/quota.h"

/* Convert a scrub type code to a DQ flag, or return 0 if error. */
xfs_dqtype_t
xchk_quota_to_dqtype(
        struct xfs_scrub        *sc)
{
        switch (sc->sm->sm_type) {
        case XFS_SCRUB_TYPE_UQUOTA:
                return XFS_DQTYPE_USER;
        case XFS_SCRUB_TYPE_GQUOTA:
                return XFS_DQTYPE_GROUP;
        case XFS_SCRUB_TYPE_PQUOTA:
                return XFS_DQTYPE_PROJ;
        default:
                return 0;
        }
}

/* Set us up to scrub a quota. */
int
xchk_setup_quota(
        struct xfs_scrub        *sc)
{
        xfs_dqtype_t            dqtype;
        int                     error;

        if (!XFS_IS_QUOTA_ON(sc->mp))
                return -ENOENT;

        dqtype = xchk_quota_to_dqtype(sc);
        if (dqtype == 0)
                return -EINVAL;

        if (!xfs_this_quota_on(sc->mp, dqtype))
                return -ENOENT;

        if (xchk_need_intent_drain(sc))
                xchk_fsgates_enable(sc, XCHK_FSGATES_DRAIN);

        error = xchk_setup_fs(sc);
        if (error)
                return error;

        error = xchk_install_live_inode(sc, xfs_quota_inode(sc->mp, dqtype));
        if (error)
                return error;

        xchk_ilock(sc, XFS_ILOCK_EXCL);
        return 0;
}

/* Quotas. */

struct xchk_quota_info {
        struct xfs_scrub        *sc;
        xfs_dqid_t              last_id;
};

/* There's a written block backing this dquot, right? */
STATIC int
xchk_quota_item_bmap(
        struct xfs_scrub        *sc,
        struct xfs_dquot        *dq,
        xfs_fileoff_t           offset)
{
        struct xfs_bmbt_irec    irec;
        struct xfs_mount        *mp = sc->mp;
        int                     nmaps = 1;
        int                     error;

        if (!xfs_verify_fileoff(mp, offset)) {
                xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);
                return 0;
        }

        if (dq->q_fileoffset != offset) {
                xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);
                return 0;
        }

        error = xfs_bmapi_read(sc->ip, offset, 1, &irec, &nmaps, 0);
        if (error)
                return error;

        if (nmaps != 1) {
                xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);
                return 0;
        }

        if (!xfs_verify_fsbno(mp, irec.br_startblock))
                xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);
        if (XFS_FSB_TO_DADDR(mp, irec.br_startblock) != dq->q_blkno)
                xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);
        if (!xfs_bmap_is_written_extent(&irec))
                xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);

        return 0;
}

/* Complain if a quota timer is incorrectly set. */
static inline void
xchk_quota_item_timer(
        struct xfs_scrub                *sc,
        xfs_fileoff_t                   offset,
        const struct xfs_dquot_res      *res)
{
        if ((res->softlimit && res->count > res->softlimit) ||
            (res->hardlimit && res->count > res->hardlimit)) {
                if (!res->timer)
                        xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);
        } else {
                if (res->timer)
                        xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);
        }
}

/* Scrub the fields in an individual quota item. */
STATIC int
xchk_quota_item(
        struct xchk_quota_info  *sqi,
        struct xfs_dquot        *dq)
{
        struct xfs_scrub        *sc = sqi->sc;
        struct xfs_mount        *mp = sc->mp;
        struct xfs_quotainfo    *qi = mp->m_quotainfo;
        xfs_fileoff_t           offset;
        xfs_ino_t               fs_icount;
        int                     error = 0;

        if (xchk_should_terminate(sc, &error))
                return error;

        /*
         * We want to validate the bmap record for the storage backing this
         * dquot, so we need to lock the dquot and the quota file.  For quota
         * operations, the locking order is first the ILOCK and then the dquot.
         */
        xchk_ilock(sc, XFS_ILOCK_SHARED);
        mutex_lock(&dq->q_qlock);

        /*
         * Except for the root dquot, the actual dquot we got must either have
         * the same or higher id as we saw before.
         */
        offset = dq->q_id / qi->qi_dqperchunk;
        if (dq->q_id && dq->q_id <= sqi->last_id)
                xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);

        sqi->last_id = dq->q_id;

        error = xchk_quota_item_bmap(sc, dq, offset);
        xchk_iunlock(sc, XFS_ILOCK_SHARED);
        if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, offset, &error)) {
                mutex_unlock(&dq->q_qlock);
                return error;
        }

        /*
         * Warn if the hard limits are larger than the fs.
         * Administrators can do this, though in production this seems
         * suspect, which is why we flag it for review.
         *
         * Complain about corruption if the soft limit is greater than
         * the hard limit.
         */
        if (dq->q_blk.hardlimit > mp->m_sb.sb_dblocks)
                xchk_fblock_set_warning(sc, XFS_DATA_FORK, offset);
        if (dq->q_blk.softlimit > dq->q_blk.hardlimit)
                xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);

        if (dq->q_ino.hardlimit > M_IGEO(mp)->maxicount)
                xchk_fblock_set_warning(sc, XFS_DATA_FORK, offset);
        if (dq->q_ino.softlimit > dq->q_ino.hardlimit)
                xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);

        if (dq->q_rtb.hardlimit > mp->m_sb.sb_rblocks)
                xchk_fblock_set_warning(sc, XFS_DATA_FORK, offset);
        if (dq->q_rtb.softlimit > dq->q_rtb.hardlimit)
                xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);

        /* Check the resource counts. */
        fs_icount = percpu_counter_sum(&mp->m_icount);

        /*
         * Check that usage doesn't exceed physical limits.  However, on
         * a reflink filesystem we're allowed to exceed physical space
         * if there are no quota limits.
         */
        if (xfs_has_reflink(mp)) {
                if (mp->m_sb.sb_dblocks < dq->q_blk.count)
                        xchk_fblock_set_warning(sc, XFS_DATA_FORK,
                                        offset);
                if (mp->m_sb.sb_rblocks < dq->q_rtb.count)
                        xchk_fblock_set_warning(sc, XFS_DATA_FORK,
                                        offset);
        } else {
                if (mp->m_sb.sb_dblocks < dq->q_blk.count)
                        xchk_fblock_set_corrupt(sc, XFS_DATA_FORK,
                                        offset);
                if (mp->m_sb.sb_rblocks < dq->q_rtb.count)
                        xchk_fblock_set_corrupt(sc, XFS_DATA_FORK,
                                        offset);
        }
        if (dq->q_ino.count > fs_icount)
                xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);

        /*
         * We can violate the hard limits if the admin suddenly sets a
         * lower limit than the actual usage.  However, we flag it for
         * admin review.
         */
        if (dq->q_id == 0)
                goto out;

        if (dq->q_blk.hardlimit != 0 &&
            dq->q_blk.count > dq->q_blk.hardlimit)
                xchk_fblock_set_warning(sc, XFS_DATA_FORK, offset);

        if (dq->q_ino.hardlimit != 0 &&
            dq->q_ino.count > dq->q_ino.hardlimit)
                xchk_fblock_set_warning(sc, XFS_DATA_FORK, offset);

        if (dq->q_rtb.hardlimit != 0 &&
            dq->q_rtb.count > dq->q_rtb.hardlimit)
                xchk_fblock_set_warning(sc, XFS_DATA_FORK, offset);

        xchk_quota_item_timer(sc, offset, &dq->q_blk);
        xchk_quota_item_timer(sc, offset, &dq->q_ino);
        xchk_quota_item_timer(sc, offset, &dq->q_rtb);

out:
        mutex_unlock(&dq->q_qlock);
        if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                return -ECANCELED;

        return 0;
}

/* Check the quota's data fork. */
STATIC int
xchk_quota_data_fork(
        struct xfs_scrub        *sc)
{
        struct xfs_bmbt_irec    irec = { 0 };
        struct xfs_iext_cursor  icur;
        struct xfs_quotainfo    *qi = sc->mp->m_quotainfo;
        struct xfs_ifork        *ifp;
        xfs_fileoff_t           max_dqid_off;
        int                     error = 0;

        /* Invoke the fork scrubber. */
        error = xchk_metadata_inode_forks(sc);
        if (error || (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
                return error;

        /* Check for data fork problems that apply only to quota files. */
        max_dqid_off = XFS_DQ_ID_MAX / qi->qi_dqperchunk;
        ifp = xfs_ifork_ptr(sc->ip, XFS_DATA_FORK);
        for_each_xfs_iext(ifp, &icur, &irec) {
                if (xchk_should_terminate(sc, &error))
                        break;

                /*
                 * delalloc/unwritten extents or blocks mapped above the highest
                 * quota id shouldn't happen.
                 */
                if (!xfs_bmap_is_written_extent(&irec) ||
                    irec.br_startoff > max_dqid_off ||
                    irec.br_startoff + irec.br_blockcount - 1 > max_dqid_off) {
                        xchk_fblock_set_corrupt(sc, XFS_DATA_FORK,
                                        irec.br_startoff);
                        break;
                }
        }

        return error;
}

/* Scrub all of a quota type's items. */
int
xchk_quota(
        struct xfs_scrub        *sc)
{
        struct xchk_dqiter      cursor = { };
        struct xchk_quota_info  sqi = { .sc = sc };
        struct xfs_mount        *mp = sc->mp;
        struct xfs_quotainfo    *qi = mp->m_quotainfo;
        struct xfs_dquot        *dq;
        xfs_dqtype_t            dqtype;
        int                     error = 0;

        dqtype = xchk_quota_to_dqtype(sc);

        /* Look for problem extents. */
        error = xchk_quota_data_fork(sc);
        if (error)
                goto out;
        if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                goto out;

        /*
         * Check all the quota items.  Now that we've checked the quota inode
         * data fork we have to drop ILOCK_EXCL to use the regular dquot
         * functions.
         */
        xchk_iunlock(sc, sc->ilock_flags);

        /* Now look for things that the quota verifiers won't complain about. */
        xchk_dqiter_init(&cursor, sc, dqtype);
        while ((error = xchk_dquot_iter(&cursor, &dq)) == 1) {
                error = xchk_quota_item(&sqi, dq);
                xfs_qm_dqrele(dq);
                if (error)
                        break;
        }
        if (error == -ECANCELED)
                error = 0;
        if (!xchk_fblock_process_error(sc, XFS_DATA_FORK,
                        sqi.last_id * qi->qi_dqperchunk, &error))
                goto out;

out:
        return error;
}