// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
 * Copyright (c) 2013 Red Hat, Inc.
 * All Rights Reserved.
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_quota.h"
#include "xfs_trans.h"
#include "xfs_qm.h"
#include "xfs_error.h"

int
xfs_calc_dquots_per_chunk(
        unsigned int            nbblks) /* basic block units */
{
        ASSERT(nbblks > 0);
        return BBTOB(nbblks) / sizeof(xfs_dqblk_t);
}

/*
 * Do some primitive error checking on ondisk dquot data structures.
 *
 * The xfs_dqblk structure /contains/ the xfs_disk_dquot structure;
 * we verify them separately because at some points we have only the
 * smaller xfs_disk_dquot structure available.
 */

xfs_failaddr_t
xfs_dquot_verify(
        struct xfs_mount *mp,
        xfs_disk_dquot_t *ddq,
        xfs_dqid_t       id,
        uint             type)    /* used only during quotacheck */
{
        /*
         * We can encounter an uninitialized dquot buffer for 2 reasons:
         * 1. If we crash while deleting the quotainode(s), and those blks got
         *    used for user data. This is because we take the path of regular
         *    file deletion; however, the size field of quotainodes is never
         *    updated, so all the tricks that we play in itruncate_finish
         *    don't quite matter.
         *
         * 2. We don't play the quota buffers when there's a quotaoff logitem.
         *    But the allocation will be replayed so we'll end up with an
         *    uninitialized quota block.
         *
         * This is all fine; things are still consistent, and we haven't lost
         * any quota information. Just don't complain about bad dquot blks.
         */
        if (ddq->d_magic != cpu_to_be16(XFS_DQUOT_MAGIC))
                return __this_address;
        if (ddq->d_version != XFS_DQUOT_VERSION)
                return __this_address;

        if (type && ddq->d_flags != type)
                return __this_address;
        if (ddq->d_flags != XFS_DQ_USER &&
            ddq->d_flags != XFS_DQ_PROJ &&
            ddq->d_flags != XFS_DQ_GROUP)
                return __this_address;

        if (id != -1 && id != be32_to_cpu(ddq->d_id))
                return __this_address;

        if (!ddq->d_id)
                return NULL;

        if (ddq->d_blk_softlimit &&
            be64_to_cpu(ddq->d_bcount) > be64_to_cpu(ddq->d_blk_softlimit) &&
            !ddq->d_btimer)
                return __this_address;

        if (ddq->d_ino_softlimit &&
            be64_to_cpu(ddq->d_icount) > be64_to_cpu(ddq->d_ino_softlimit) &&
            !ddq->d_itimer)
                return __this_address;

        if (ddq->d_rtb_softlimit &&
            be64_to_cpu(ddq->d_rtbcount) > be64_to_cpu(ddq->d_rtb_softlimit) &&
            !ddq->d_rtbtimer)
                return __this_address;

        return NULL;
}

xfs_failaddr_t
xfs_dqblk_verify(
        struct xfs_mount        *mp,
        struct xfs_dqblk        *dqb,
        xfs_dqid_t              id,
        uint                    type)   /* used only during quotacheck */
{
        if (xfs_sb_version_hascrc(&mp->m_sb) &&
            !uuid_equal(&dqb->dd_uuid, &mp->m_sb.sb_meta_uuid))
                return __this_address;

        return xfs_dquot_verify(mp, &dqb->dd_diskdq, id, type);
}

/*
 * Do some primitive error checking on ondisk dquot data structures.
 */
void
xfs_dqblk_repair(
        struct xfs_mount        *mp,
        struct xfs_dqblk        *dqb,
        xfs_dqid_t              id,
        uint                    type)
{
        /*
         * Typically, a repair is only requested by quotacheck.
         */
        ASSERT(id != -1);
        memset(dqb, 0, sizeof(xfs_dqblk_t));

        dqb->dd_diskdq.d_magic = cpu_to_be16(XFS_DQUOT_MAGIC);
        dqb->dd_diskdq.d_version = XFS_DQUOT_VERSION;
        dqb->dd_diskdq.d_flags = type;
        dqb->dd_diskdq.d_id = cpu_to_be32(id);

        if (xfs_sb_version_hascrc(&mp->m_sb)) {
                uuid_copy(&dqb->dd_uuid, &mp->m_sb.sb_meta_uuid);
                xfs_update_cksum((char *)dqb, sizeof(struct xfs_dqblk),
                                 XFS_DQUOT_CRC_OFF);
        }
}

STATIC bool
xfs_dquot_buf_verify_crc(
        struct xfs_mount        *mp,
        struct xfs_buf          *bp,
        bool                    readahead)
{
        struct xfs_dqblk        *d = (struct xfs_dqblk *)bp->b_addr;
        int                     ndquots;
        int                     i;

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

        /*
         * if we are in log recovery, the quota subsystem has not been
         * initialised so we have no quotainfo structure. In that case, we need
         * to manually calculate the number of dquots in the buffer.
         */
        if (mp->m_quotainfo)
                ndquots = mp->m_quotainfo->qi_dqperchunk;
        else
                ndquots = xfs_calc_dquots_per_chunk(bp->b_length);

        for (i = 0; i < ndquots; i++, d++) {
                if (!xfs_verify_cksum((char *)d, sizeof(struct xfs_dqblk),
                                 XFS_DQUOT_CRC_OFF)) {
                        if (!readahead)
                                xfs_buf_verifier_error(bp, -EFSBADCRC, __func__,
                                        d, sizeof(*d), __this_address);
                        return false;
                }
        }
        return true;
}

STATIC xfs_failaddr_t
xfs_dquot_buf_verify(
        struct xfs_mount        *mp,
        struct xfs_buf          *bp,
        bool                    readahead)
{
        struct xfs_dqblk        *dqb = bp->b_addr;
        xfs_failaddr_t          fa;
        xfs_dqid_t              id = 0;
        int                     ndquots;
        int                     i;

        /*
         * if we are in log recovery, the quota subsystem has not been
         * initialised so we have no quotainfo structure. In that case, we need
         * to manually calculate the number of dquots in the buffer.
         */
        if (mp->m_quotainfo)
                ndquots = mp->m_quotainfo->qi_dqperchunk;
        else
                ndquots = xfs_calc_dquots_per_chunk(bp->b_length);

        /*
         * On the first read of the buffer, verify that each dquot is valid.
         * We don't know what the id of the dquot is supposed to be, just that
         * they should be increasing monotonically within the buffer. If the
         * first id is corrupt, then it will fail on the second dquot in the
         * buffer so corruptions could point to the wrong dquot in this case.
         */
        for (i = 0; i < ndquots; i++) {
                struct xfs_disk_dquot   *ddq;

                ddq = &dqb[i].dd_diskdq;

                if (i == 0)
                        id = be32_to_cpu(ddq->d_id);

                fa = xfs_dqblk_verify(mp, &dqb[i], id + i, 0);
                if (fa) {
                        if (!readahead)
                                xfs_buf_verifier_error(bp, -EFSCORRUPTED,
                                        __func__, &dqb[i],
                                        sizeof(struct xfs_dqblk), fa);
                        return fa;
                }
        }

        return NULL;
}

static xfs_failaddr_t
xfs_dquot_buf_verify_struct(
        struct xfs_buf          *bp)
{
        struct xfs_mount        *mp = bp->b_mount;

        return xfs_dquot_buf_verify(mp, bp, false);
}

static void
xfs_dquot_buf_read_verify(
        struct xfs_buf          *bp)
{
        struct xfs_mount        *mp = bp->b_mount;

        if (!xfs_dquot_buf_verify_crc(mp, bp, false))
                return;
        xfs_dquot_buf_verify(mp, bp, false);
}

/*
 * readahead errors are silent and simply leave the buffer as !done so a real
 * read will then be run with the xfs_dquot_buf_ops verifier. See
 * xfs_inode_buf_verify() for why we use EIO and ~XBF_DONE here rather than
 * reporting the failure.
 */
static void
xfs_dquot_buf_readahead_verify(
        struct xfs_buf  *bp)
{
        struct xfs_mount        *mp = bp->b_mount;

        if (!xfs_dquot_buf_verify_crc(mp, bp, true) ||
            xfs_dquot_buf_verify(mp, bp, true) != NULL) {
                xfs_buf_ioerror(bp, -EIO);
                bp->b_flags &= ~XBF_DONE;
        }
}

/*
 * we don't calculate the CRC here as that is done when the dquot is flushed to
 * the buffer after the update is done. This ensures that the dquot in the
 * buffer always has an up-to-date CRC value.
 */
static void
xfs_dquot_buf_write_verify(
        struct xfs_buf          *bp)
{
        struct xfs_mount        *mp = bp->b_mount;

        xfs_dquot_buf_verify(mp, bp, false);
}

const struct xfs_buf_ops xfs_dquot_buf_ops = {
        .name = "xfs_dquot",
        .magic16 = { cpu_to_be16(XFS_DQUOT_MAGIC),
                     cpu_to_be16(XFS_DQUOT_MAGIC) },
        .verify_read = xfs_dquot_buf_read_verify,
        .verify_write = xfs_dquot_buf_write_verify,
        .verify_struct = xfs_dquot_buf_verify_struct,
};

const struct xfs_buf_ops xfs_dquot_buf_ra_ops = {
        .name = "xfs_dquot_ra",
        .magic16 = { cpu_to_be16(XFS_DQUOT_MAGIC),
                     cpu_to_be16(XFS_DQUOT_MAGIC) },
        .verify_read = xfs_dquot_buf_readahead_verify,
        .verify_write = xfs_dquot_buf_write_verify,
};