// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 */
#include "xfs_platform.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_mount.h"
#include "xfs_inode.h"
#include "xfs_iwalk.h"
#include "xfs_quota.h"
#include "xfs_bmap.h"
#include "xfs_bmap_util.h"
#include "xfs_trans.h"
#include "xfs_trans_space.h"
#include "xfs_qm.h"
#include "xfs_trace.h"
#include "xfs_icache.h"
#include "xfs_error.h"
#include "xfs_ag.h"
#include "xfs_ialloc.h"
#include "xfs_log_priv.h"
#include "xfs_health.h"
#include "xfs_da_format.h"
#include "xfs_metafile.h"
#include "xfs_rtgroup.h"

/*
 * The global quota manager. There is only one of these for the entire
 * system, _not_ one per file system. XQM keeps track of the overall
 * quota functionality, including maintaining the freelist and hash
 * tables of dquots.
 */
STATIC int      xfs_qm_init_quotainos(struct xfs_mount *mp);
STATIC int      xfs_qm_init_quotainfo(struct xfs_mount *mp);

STATIC void     xfs_qm_dqfree_one(struct xfs_dquot *dqp);
/*
 * We use the batch lookup interface to iterate over the dquots as it
 * currently is the only interface into the radix tree code that allows
 * fuzzy lookups instead of exact matches.  Holding the lock over multiple
 * operations is fine as all callers are used either during mount/umount
 * or quotaoff.
 */
#define XFS_DQ_LOOKUP_BATCH     32

STATIC int
xfs_qm_dquot_walk(
        struct xfs_mount        *mp,
        xfs_dqtype_t            type,
        int                     (*execute)(struct xfs_dquot *dqp, void *data),
        void                    *data)
{
        struct xfs_quotainfo    *qi = mp->m_quotainfo;
        struct radix_tree_root  *tree = xfs_dquot_tree(qi, type);
        uint32_t                next_index;
        int                     last_error = 0;
        int                     skipped;
        int                     nr_found;

restart:
        skipped = 0;
        next_index = 0;
        nr_found = 0;

        while (1) {
                struct xfs_dquot *batch[XFS_DQ_LOOKUP_BATCH];
                int             error;
                int             i;

                mutex_lock(&qi->qi_tree_lock);
                nr_found = radix_tree_gang_lookup(tree, (void **)batch,
                                        next_index, XFS_DQ_LOOKUP_BATCH);
                if (!nr_found) {
                        mutex_unlock(&qi->qi_tree_lock);
                        break;
                }

                for (i = 0; i < nr_found; i++) {
                        struct xfs_dquot *dqp = batch[i];

                        next_index = dqp->q_id + 1;

                        error = execute(batch[i], data);
                        if (error == -EAGAIN) {
                                skipped++;
                                continue;
                        }
                        if (error && last_error != -EFSCORRUPTED)
                                last_error = error;
                }

                mutex_unlock(&qi->qi_tree_lock);

                /* bail out if the filesystem is corrupted.  */
                if (last_error == -EFSCORRUPTED) {
                        skipped = 0;
                        break;
                }
                /* we're done if id overflows back to zero */
                if (!next_index)
                        break;
        }

        if (skipped) {
                delay(1);
                goto restart;
        }

        return last_error;
}


/*
 * Purge a dquot from all tracking data structures and free it.
 */
STATIC int
xfs_qm_dqpurge(
        struct xfs_dquot        *dqp,
        void                    *data)
{
        struct xfs_quotainfo    *qi = dqp->q_mount->m_quotainfo;

        spin_lock(&dqp->q_lockref.lock);
        if (dqp->q_lockref.count > 0 || __lockref_is_dead(&dqp->q_lockref)) {
                spin_unlock(&dqp->q_lockref.lock);
                return -EAGAIN;
        }
        lockref_mark_dead(&dqp->q_lockref);
        spin_unlock(&dqp->q_lockref.lock);

        mutex_lock(&dqp->q_qlock);
        xfs_qm_dqunpin_wait(dqp);
        xfs_dqflock(dqp);

        /*
         * If we are turning this type of quotas off, we don't care
         * about the dirty metadata sitting in this dquot. OTOH, if
         * we're unmounting, we do care, so we flush it and wait.
         */
        if (XFS_DQ_IS_DIRTY(dqp)) {
                struct xfs_buf  *bp = NULL;
                int             error;

                /*
                 * We don't care about getting disk errors here. We need
                 * to purge this dquot anyway, so we go ahead regardless.
                 */
                error = xfs_dquot_use_attached_buf(dqp, &bp);
                if (error == -EAGAIN) {
                        /* resurrect the refcount from the dead. */
                        dqp->q_lockref.count = 0;
                        goto out_funlock;
                }
                if (!bp)
                        goto out_funlock;

                /*
                 * dqflush completes dqflock on error, and the bwrite ioend
                 * does it on success.
                 */
                error = xfs_qm_dqflush(dqp, bp);
                if (!error) {
                        error = xfs_bwrite(bp);
                        xfs_buf_relse(bp);
                }
                xfs_dqflock(dqp);
        }
        xfs_dquot_detach_buf(dqp);

out_funlock:
        ASSERT(atomic_read(&dqp->q_pincount) == 0);
        ASSERT(xlog_is_shutdown(dqp->q_logitem.qli_item.li_log) ||
                !test_bit(XFS_LI_IN_AIL, &dqp->q_logitem.qli_item.li_flags));

        xfs_dqfunlock(dqp);
        mutex_unlock(&dqp->q_qlock);

        radix_tree_delete(xfs_dquot_tree(qi, xfs_dquot_type(dqp)), dqp->q_id);
        qi->qi_dquots--;

        /*
         * We move dquots to the freelist as soon as their reference count
         * hits zero, so it really should be on the freelist here.
         */
        ASSERT(!list_empty(&dqp->q_lru));
        list_lru_del_obj(&qi->qi_lru, &dqp->q_lru);
        XFS_STATS_DEC(dqp->q_mount, xs_qm_dquot_unused);

        xfs_qm_dqdestroy(dqp);
        return 0;
}

/*
 * Purge the dquot cache.
 */
static void
xfs_qm_dqpurge_all(
        struct xfs_mount        *mp)
{
        xfs_qm_dquot_walk(mp, XFS_DQTYPE_USER, xfs_qm_dqpurge, NULL);
        xfs_qm_dquot_walk(mp, XFS_DQTYPE_GROUP, xfs_qm_dqpurge, NULL);
        xfs_qm_dquot_walk(mp, XFS_DQTYPE_PROJ, xfs_qm_dqpurge, NULL);
}

/*
 * Just destroy the quotainfo structure.
 */
void
xfs_qm_unmount(
        struct xfs_mount        *mp)
{
        if (mp->m_quotainfo) {
                xfs_qm_dqpurge_all(mp);
                xfs_qm_destroy_quotainfo(mp);
        }
}

static void
xfs_qm_unmount_rt(
        struct xfs_mount        *mp)
{
        struct xfs_rtgroup      *rtg = xfs_rtgroup_grab(mp, 0);

        if (!rtg)
                return;
        if (rtg_bitmap(rtg))
                xfs_qm_dqdetach(rtg_bitmap(rtg));
        if (rtg_summary(rtg))
                xfs_qm_dqdetach(rtg_summary(rtg));
        xfs_rtgroup_rele(rtg);
}

STATIC void
xfs_qm_destroy_quotainos(
        struct xfs_quotainfo    *qi)
{
        if (qi->qi_uquotaip) {
                xfs_irele(qi->qi_uquotaip);
                qi->qi_uquotaip = NULL; /* paranoia */
        }
        if (qi->qi_gquotaip) {
                xfs_irele(qi->qi_gquotaip);
                qi->qi_gquotaip = NULL;
        }
        if (qi->qi_pquotaip) {
                xfs_irele(qi->qi_pquotaip);
                qi->qi_pquotaip = NULL;
        }
        if (qi->qi_dirip) {
                xfs_irele(qi->qi_dirip);
                qi->qi_dirip = NULL;
        }
}

/*
 * Called from the vfsops layer.
 */
void
xfs_qm_unmount_quotas(
        xfs_mount_t     *mp)
{
        /*
         * Release the dquots that root inode, et al might be holding,
         * before we flush quotas and blow away the quotainfo structure.
         */
        ASSERT(mp->m_rootip);
        xfs_qm_dqdetach(mp->m_rootip);

        /*
         * For pre-RTG file systems, the RT inodes have quotas attached,
         * detach them now.
         */
        if (!xfs_has_rtgroups(mp))
                xfs_qm_unmount_rt(mp);

        /*
         * Release the quota inodes.
         */
        if (mp->m_quotainfo)
                xfs_qm_destroy_quotainos(mp->m_quotainfo);
}

static bool
xfs_qm_need_dqattach(
        struct xfs_inode        *ip)
{
        struct xfs_mount        *mp = ip->i_mount;

        if (!XFS_IS_QUOTA_ON(mp))
                return false;
        if (!XFS_NOT_DQATTACHED(mp, ip))
                return false;
        if (xfs_is_quota_inode(&mp->m_sb, ip->i_ino))
                return false;
        if (xfs_is_metadir_inode(ip))
                return false;
        return true;
}

/*
 * Given a locked inode, attach dquot(s) to it, taking U/G/P-QUOTAON
 * into account.
 * If @doalloc is true, the dquot(s) will be allocated if needed.
 * Inode may get unlocked and relocked in here, and the caller must deal with
 * the consequences.
 */
int
xfs_qm_dqattach_locked(
        xfs_inode_t     *ip,
        bool            doalloc)
{
        xfs_mount_t     *mp = ip->i_mount;
        int             error = 0;

        if (!xfs_qm_need_dqattach(ip))
                return 0;

        xfs_assert_ilocked(ip, XFS_ILOCK_EXCL);
        ASSERT(!xfs_is_metadir_inode(ip));

        if (XFS_IS_UQUOTA_ON(mp) && !ip->i_udquot) {
                error = xfs_qm_dqget_inode(ip, XFS_DQTYPE_USER,
                                doalloc, &ip->i_udquot);
                if (error)
                        goto done;
                ASSERT(ip->i_udquot);
        }

        if (XFS_IS_GQUOTA_ON(mp) && !ip->i_gdquot) {
                error = xfs_qm_dqget_inode(ip, XFS_DQTYPE_GROUP,
                                doalloc, &ip->i_gdquot);
                if (error)
                        goto done;
                ASSERT(ip->i_gdquot);
        }

        if (XFS_IS_PQUOTA_ON(mp) && !ip->i_pdquot) {
                error = xfs_qm_dqget_inode(ip, XFS_DQTYPE_PROJ,
                                doalloc, &ip->i_pdquot);
                if (error)
                        goto done;
                ASSERT(ip->i_pdquot);
        }

done:
        /*
         * Don't worry about the dquots that we may have attached before any
         * error - they'll get detached later if it has not already been done.
         */
        xfs_assert_ilocked(ip, XFS_ILOCK_EXCL);
        return error;
}

int
xfs_qm_dqattach(
        struct xfs_inode        *ip)
{
        int                     error;

        if (!xfs_qm_need_dqattach(ip))
                return 0;

        xfs_ilock(ip, XFS_ILOCK_EXCL);
        error = xfs_qm_dqattach_locked(ip, false);
        xfs_iunlock(ip, XFS_ILOCK_EXCL);

        return error;
}

/*
 * Release dquots (and their references) if any.
 * The inode should be locked EXCL except when this's called by
 * xfs_ireclaim.
 */
void
xfs_qm_dqdetach(
        xfs_inode_t     *ip)
{
        if (xfs_is_metadir_inode(ip))
                return;
        if (!(ip->i_udquot || ip->i_gdquot || ip->i_pdquot))
                return;

        trace_xfs_dquot_dqdetach(ip);

        ASSERT(!xfs_is_quota_inode(&ip->i_mount->m_sb, ip->i_ino));
        if (ip->i_udquot) {
                xfs_qm_dqrele(ip->i_udquot);
                ip->i_udquot = NULL;
        }
        if (ip->i_gdquot) {
                xfs_qm_dqrele(ip->i_gdquot);
                ip->i_gdquot = NULL;
        }
        if (ip->i_pdquot) {
                xfs_qm_dqrele(ip->i_pdquot);
                ip->i_pdquot = NULL;
        }
}

struct xfs_qm_isolate {
        struct list_head        buffers;
        struct list_head        dispose;
};

static enum lru_status
xfs_qm_dquot_isolate(
        struct list_head        *item,
        struct list_lru_one     *lru,
        void                    *arg)
                __releases(&lru->lock) __acquires(&lru->lock)
{
        struct xfs_dquot        *dqp = container_of(item,
                                                struct xfs_dquot, q_lru);
        struct xfs_qm_isolate   *isol = arg;
        enum lru_status         ret = LRU_SKIP;

        if (!spin_trylock(&dqp->q_lockref.lock))
                goto out_miss_busy;

        /*
         * If something else is freeing this dquot and hasn't yet removed it
         * from the LRU, leave it for the freeing task to complete the freeing
         * process rather than risk it being free from under us here.
         */
        if (__lockref_is_dead(&dqp->q_lockref))
                goto out_miss_unlock;

        /*
         * If the dquot is pinned or dirty, rotate it to the end of the LRU to
         * give some time for it to be cleaned before we try to isolate it
         * again.
         */
        ret = LRU_ROTATE;
        if (XFS_DQ_IS_DIRTY(dqp) || atomic_read(&dqp->q_pincount) > 0)
                goto out_miss_unlock;

        /*
         * This dquot has acquired a reference in the meantime remove it from
         * the freelist and try again.
         */
        if (dqp->q_lockref.count) {
                spin_unlock(&dqp->q_lockref.lock);
                XFS_STATS_INC(dqp->q_mount, xs_qm_dqwants);

                trace_xfs_dqreclaim_want(dqp);
                list_lru_isolate(lru, &dqp->q_lru);
                XFS_STATS_DEC(dqp->q_mount, xs_qm_dquot_unused);
                return LRU_REMOVED;
        }

        /*
         * The dquot may still be under IO, in which case the flush lock will be
         * held. If we can't get the flush lock now, just skip over the dquot as
         * if it was dirty.
         */
        if (!xfs_dqflock_nowait(dqp))
                goto out_miss_unlock;

        ASSERT(!XFS_DQ_IS_DIRTY(dqp));
        xfs_dquot_detach_buf(dqp);
        xfs_dqfunlock(dqp);

        /*
         * Prevent lookups now that we are past the point of no return.
         */
        lockref_mark_dead(&dqp->q_lockref);
        spin_unlock(&dqp->q_lockref.lock);

        list_lru_isolate_move(lru, &dqp->q_lru, &isol->dispose);
        XFS_STATS_DEC(dqp->q_mount, xs_qm_dquot_unused);
        trace_xfs_dqreclaim_done(dqp);
        XFS_STATS_INC(dqp->q_mount, xs_qm_dqreclaims);
        return LRU_REMOVED;

out_miss_unlock:
        spin_unlock(&dqp->q_lockref.lock);
out_miss_busy:
        trace_xfs_dqreclaim_busy(dqp);
        XFS_STATS_INC(dqp->q_mount, xs_qm_dqreclaim_misses);
        return ret;
}

static unsigned long
xfs_qm_shrink_scan(
        struct shrinker         *shrink,
        struct shrink_control   *sc)
{
        struct xfs_quotainfo    *qi = shrink->private_data;
        struct xfs_qm_isolate   isol;
        unsigned long           freed;
        int                     error;

        if ((sc->gfp_mask & (__GFP_FS|__GFP_DIRECT_RECLAIM)) != (__GFP_FS|__GFP_DIRECT_RECLAIM))
                return 0;

        INIT_LIST_HEAD(&isol.buffers);
        INIT_LIST_HEAD(&isol.dispose);

        freed = list_lru_shrink_walk(&qi->qi_lru, sc,
                                     xfs_qm_dquot_isolate, &isol);

        error = xfs_buf_delwri_submit(&isol.buffers);
        if (error)
                xfs_warn(NULL, "%s: dquot reclaim failed", __func__);

        while (!list_empty(&isol.dispose)) {
                struct xfs_dquot        *dqp;

                dqp = list_first_entry(&isol.dispose, struct xfs_dquot, q_lru);
                list_del_init(&dqp->q_lru);
                xfs_qm_dqfree_one(dqp);
        }

        return freed;
}

static unsigned long
xfs_qm_shrink_count(
        struct shrinker         *shrink,
        struct shrink_control   *sc)
{
        struct xfs_quotainfo    *qi = shrink->private_data;

        return list_lru_shrink_count(&qi->qi_lru, sc);
}

STATIC void
xfs_qm_set_defquota(
        struct xfs_mount        *mp,
        xfs_dqtype_t            type,
        struct xfs_quotainfo    *qinf)
{
        struct xfs_dquot        *dqp;
        struct xfs_def_quota    *defq;
        int                     error;

        error = xfs_qm_dqget_uncached(mp, 0, type, &dqp);
        if (error)
                return;

        defq = xfs_get_defquota(qinf, xfs_dquot_type(dqp));

        /*
         * Timers and warnings have been already set, let's just set the
         * default limits for this quota type
         */
        defq->blk.hard = dqp->q_blk.hardlimit;
        defq->blk.soft = dqp->q_blk.softlimit;
        defq->ino.hard = dqp->q_ino.hardlimit;
        defq->ino.soft = dqp->q_ino.softlimit;
        defq->rtb.hard = dqp->q_rtb.hardlimit;
        defq->rtb.soft = dqp->q_rtb.softlimit;
        xfs_qm_dqdestroy(dqp);
}

/* Initialize quota time limits from the root dquot. */
static void
xfs_qm_init_timelimits(
        struct xfs_mount        *mp,
        xfs_dqtype_t            type)
{
        struct xfs_quotainfo    *qinf = mp->m_quotainfo;
        struct xfs_def_quota    *defq;
        struct xfs_dquot        *dqp;
        int                     error;

        defq = xfs_get_defquota(qinf, type);

        defq->blk.time = XFS_QM_BTIMELIMIT;
        defq->ino.time = XFS_QM_ITIMELIMIT;
        defq->rtb.time = XFS_QM_RTBTIMELIMIT;

        /*
         * We try to get the limits from the superuser's limits fields.
         * This is quite hacky, but it is standard quota practice.
         *
         * Since we may not have done a quotacheck by this point, just read
         * the dquot without attaching it to any hashtables or lists.
         */
        error = xfs_qm_dqget_uncached(mp, 0, type, &dqp);
        if (error)
                return;

        /*
         * The warnings and timers set the grace period given to
         * a user or group before he or she can not perform any
         * more writing. If it is zero, a default is used.
         */
        if (dqp->q_blk.timer)
                defq->blk.time = dqp->q_blk.timer;
        if (dqp->q_ino.timer)
                defq->ino.time = dqp->q_ino.timer;
        if (dqp->q_rtb.timer)
                defq->rtb.time = dqp->q_rtb.timer;

        xfs_qm_dqdestroy(dqp);
}

static int
xfs_qm_load_metadir_qinos(
        struct xfs_mount        *mp,
        struct xfs_quotainfo    *qi)
{
        struct xfs_trans        *tp;
        int                     error;

        tp = xfs_trans_alloc_empty(mp);
        error = xfs_dqinode_load_parent(tp, &qi->qi_dirip);
        if (error == -ENOENT) {
                /* no quota dir directory, but we'll create one later */
                error = 0;
                goto out_trans;
        }
        if (error)
                goto out_trans;

        if (XFS_IS_UQUOTA_ON(mp)) {
                error = xfs_dqinode_load(tp, qi->qi_dirip, XFS_DQTYPE_USER,
                                &qi->qi_uquotaip);
                if (error && error != -ENOENT)
                        goto out_trans;
        }

        if (XFS_IS_GQUOTA_ON(mp)) {
                error = xfs_dqinode_load(tp, qi->qi_dirip, XFS_DQTYPE_GROUP,
                                &qi->qi_gquotaip);
                if (error && error != -ENOENT)
                        goto out_trans;
        }

        if (XFS_IS_PQUOTA_ON(mp)) {
                error = xfs_dqinode_load(tp, qi->qi_dirip, XFS_DQTYPE_PROJ,
                                &qi->qi_pquotaip);
                if (error && error != -ENOENT)
                        goto out_trans;
        }

        error = 0;
out_trans:
        xfs_trans_cancel(tp);
        return error;
}

/* Create quota inodes in the metadata directory tree. */
STATIC int
xfs_qm_create_metadir_qinos(
        struct xfs_mount        *mp,
        struct xfs_quotainfo    *qi)
{
        int                     error;

        if (!qi->qi_dirip) {
                error = xfs_dqinode_mkdir_parent(mp, &qi->qi_dirip);
                if (error && error != -EEXIST)
                        return error;
                /*
                 * If the /quotas dirent points to an inode that isn't
                 * loadable, qi_dirip will be NULL but mkdir_parent will return
                 * -EEXIST.  In this case the metadir is corrupt, so bail out.
                 */
                if (XFS_IS_CORRUPT(mp, qi->qi_dirip == NULL))
                        return -EFSCORRUPTED;
        }

        if (XFS_IS_UQUOTA_ON(mp) && !qi->qi_uquotaip) {
                error = xfs_dqinode_metadir_create(qi->qi_dirip,
                                XFS_DQTYPE_USER, &qi->qi_uquotaip);
                if (error)
                        return error;
        }

        if (XFS_IS_GQUOTA_ON(mp) && !qi->qi_gquotaip) {
                error = xfs_dqinode_metadir_create(qi->qi_dirip,
                                XFS_DQTYPE_GROUP, &qi->qi_gquotaip);
                if (error)
                        return error;
        }

        if (XFS_IS_PQUOTA_ON(mp) && !qi->qi_pquotaip) {
                error = xfs_dqinode_metadir_create(qi->qi_dirip,
                                XFS_DQTYPE_PROJ, &qi->qi_pquotaip);
                if (error)
                        return error;
        }

        return 0;
}

/*
 * Add QUOTABIT to sb_versionnum and initialize qflags in preparation for
 * creating quota files on a metadir filesystem.
 */
STATIC int
xfs_qm_prep_metadir_sb(
        struct xfs_mount        *mp)
{
        struct xfs_trans        *tp;
        int                     error;

        error = xfs_trans_alloc(mp, &M_RES(mp)->tr_sb, 0, 0, 0, &tp);
        if (error)
                return error;

        spin_lock(&mp->m_sb_lock);

        xfs_add_quota(mp);

        /* qflags will get updated fully _after_ quotacheck */
        mp->m_sb.sb_qflags = mp->m_qflags & XFS_ALL_QUOTA_ACCT;

        spin_unlock(&mp->m_sb_lock);
        xfs_log_sb(tp);

        return xfs_trans_commit(tp);
}

/*
 * Load existing quota inodes or create them.  Since this is a V5 filesystem,
 * we don't have to deal with the grp/prjquota switcheroo thing from V4.
 */
STATIC int
xfs_qm_init_metadir_qinos(
        struct xfs_mount        *mp)
{
        struct xfs_quotainfo    *qi = mp->m_quotainfo;
        int                     error;

        if (!xfs_has_quota(mp)) {
                error = xfs_qm_prep_metadir_sb(mp);
                if (error)
                        return error;
        }

        error = xfs_qm_load_metadir_qinos(mp, qi);
        if (error)
                goto out_err;

        error = xfs_qm_create_metadir_qinos(mp, qi);
        if (error)
                goto out_err;

        /* The only user of the quota dir inode is online fsck */
#if !IS_ENABLED(CONFIG_XFS_ONLINE_SCRUB)
        xfs_irele(qi->qi_dirip);
        qi->qi_dirip = NULL;
#endif
        return 0;
out_err:
        xfs_qm_destroy_quotainos(mp->m_quotainfo);
        return error;
}

/*
 * This initializes all the quota information that's kept in the
 * mount structure
 */
STATIC int
xfs_qm_init_quotainfo(
        struct xfs_mount        *mp)
{
        struct xfs_quotainfo    *qinf;
        int                     error;

        ASSERT(XFS_IS_QUOTA_ON(mp));

        qinf = mp->m_quotainfo = kzalloc_obj(struct xfs_quotainfo,
                                             GFP_KERNEL | __GFP_NOFAIL);

        error = list_lru_init(&qinf->qi_lru);
        if (error)
                goto out_free_qinf;

        /*
         * See if quotainodes are setup, and if not, allocate them,
         * and change the superblock accordingly.
         */
        if (xfs_has_metadir(mp))
                error = xfs_qm_init_metadir_qinos(mp);
        else
                error = xfs_qm_init_quotainos(mp);
        if (error)
                goto out_free_lru;

        INIT_RADIX_TREE(&qinf->qi_uquota_tree, GFP_KERNEL);
        INIT_RADIX_TREE(&qinf->qi_gquota_tree, GFP_KERNEL);
        INIT_RADIX_TREE(&qinf->qi_pquota_tree, GFP_KERNEL);
        mutex_init(&qinf->qi_tree_lock);

        /* mutex used to serialize quotaoffs */
        mutex_init(&qinf->qi_quotaofflock);

        /* Precalc some constants */
        qinf->qi_dqchunklen = XFS_FSB_TO_BB(mp, XFS_DQUOT_CLUSTER_SIZE_FSB);
        qinf->qi_dqperchunk = xfs_calc_dquots_per_chunk(qinf->qi_dqchunklen);
        if (xfs_has_bigtime(mp)) {
                qinf->qi_expiry_min =
                        xfs_dq_bigtime_to_unix(XFS_DQ_BIGTIME_EXPIRY_MIN);
                qinf->qi_expiry_max =
                        xfs_dq_bigtime_to_unix(XFS_DQ_BIGTIME_EXPIRY_MAX);
        } else {
                qinf->qi_expiry_min = XFS_DQ_LEGACY_EXPIRY_MIN;
                qinf->qi_expiry_max = XFS_DQ_LEGACY_EXPIRY_MAX;
        }
        trace_xfs_quota_expiry_range(mp, qinf->qi_expiry_min,
                        qinf->qi_expiry_max);

        mp->m_qflags |= (mp->m_sb.sb_qflags & XFS_ALL_QUOTA_CHKD);

        xfs_qm_init_timelimits(mp, XFS_DQTYPE_USER);
        xfs_qm_init_timelimits(mp, XFS_DQTYPE_GROUP);
        xfs_qm_init_timelimits(mp, XFS_DQTYPE_PROJ);

        if (XFS_IS_UQUOTA_ON(mp))
                xfs_qm_set_defquota(mp, XFS_DQTYPE_USER, qinf);
        if (XFS_IS_GQUOTA_ON(mp))
                xfs_qm_set_defquota(mp, XFS_DQTYPE_GROUP, qinf);
        if (XFS_IS_PQUOTA_ON(mp))
                xfs_qm_set_defquota(mp, XFS_DQTYPE_PROJ, qinf);

        qinf->qi_shrinker = shrinker_alloc(SHRINKER_NUMA_AWARE, "xfs-qm:%s",
                                           mp->m_super->s_id);
        if (!qinf->qi_shrinker) {
                error = -ENOMEM;
                goto out_free_inos;
        }

        qinf->qi_shrinker->count_objects = xfs_qm_shrink_count;
        qinf->qi_shrinker->scan_objects = xfs_qm_shrink_scan;
        qinf->qi_shrinker->private_data = qinf;

        shrinker_register(qinf->qi_shrinker);

        xfs_hooks_init(&qinf->qi_mod_ino_dqtrx_hooks);
        xfs_hooks_init(&qinf->qi_apply_dqtrx_hooks);

        return 0;

out_free_inos:
        mutex_destroy(&qinf->qi_quotaofflock);
        mutex_destroy(&qinf->qi_tree_lock);
        xfs_qm_destroy_quotainos(qinf);
out_free_lru:
        list_lru_destroy(&qinf->qi_lru);
out_free_qinf:
        kfree(qinf);
        mp->m_quotainfo = NULL;
        return error;
}

/*
 * Gets called when unmounting a filesystem or when all quotas get
 * turned off.
 * This purges the quota inodes, destroys locks and frees itself.
 */
void
xfs_qm_destroy_quotainfo(
        struct xfs_mount        *mp)
{
        struct xfs_quotainfo    *qi;

        qi = mp->m_quotainfo;
        ASSERT(qi != NULL);

        shrinker_free(qi->qi_shrinker);
        list_lru_destroy(&qi->qi_lru);
        xfs_qm_destroy_quotainos(qi);
        mutex_destroy(&qi->qi_tree_lock);
        mutex_destroy(&qi->qi_quotaofflock);
        kfree(qi);
        mp->m_quotainfo = NULL;
}

static inline enum xfs_metafile_type
xfs_qm_metafile_type(
        unsigned int            flags)
{
        if (flags & XFS_QMOPT_UQUOTA)
                return XFS_METAFILE_USRQUOTA;
        else if (flags & XFS_QMOPT_GQUOTA)
                return XFS_METAFILE_GRPQUOTA;
        return XFS_METAFILE_PRJQUOTA;
}

/*
 * Create an inode and return with a reference already taken, but unlocked
 * This is how we create quota inodes
 */
STATIC int
xfs_qm_qino_alloc(
        struct xfs_mount        *mp,
        struct xfs_inode        **ipp,
        unsigned int            flags)
{
        struct xfs_trans        *tp;
        enum xfs_metafile_type  metafile_type = xfs_qm_metafile_type(flags);
        int                     error;
        bool                    need_alloc = true;

        *ipp = NULL;
        /*
         * With superblock that doesn't have separate pquotino, we
         * share an inode between gquota and pquota. If the on-disk
         * superblock has GQUOTA and the filesystem is now mounted
         * with PQUOTA, just use sb_gquotino for sb_pquotino and
         * vice-versa.
         */
        if (!xfs_has_pquotino(mp) &&
                        (flags & (XFS_QMOPT_PQUOTA|XFS_QMOPT_GQUOTA))) {
                xfs_ino_t ino = NULLFSINO;

                if ((flags & XFS_QMOPT_PQUOTA) &&
                             (mp->m_sb.sb_gquotino != NULLFSINO)) {
                        ino = mp->m_sb.sb_gquotino;
                        if (XFS_IS_CORRUPT(mp,
                                           mp->m_sb.sb_pquotino != NULLFSINO)) {
                                xfs_fs_mark_sick(mp, XFS_SICK_FS_PQUOTA);
                                return -EFSCORRUPTED;
                        }
                } else if ((flags & XFS_QMOPT_GQUOTA) &&
                             (mp->m_sb.sb_pquotino != NULLFSINO)) {
                        ino = mp->m_sb.sb_pquotino;
                        if (XFS_IS_CORRUPT(mp,
                                           mp->m_sb.sb_gquotino != NULLFSINO)) {
                                xfs_fs_mark_sick(mp, XFS_SICK_FS_GQUOTA);
                                return -EFSCORRUPTED;
                        }
                }
                if (ino != NULLFSINO) {
                        error = xfs_metafile_iget(mp, ino, metafile_type, ipp);
                        if (error)
                                return error;

                        mp->m_sb.sb_gquotino = NULLFSINO;
                        mp->m_sb.sb_pquotino = NULLFSINO;
                        need_alloc = false;
                }
        }

        error = xfs_trans_alloc(mp, &M_RES(mp)->tr_create,
                        need_alloc ? XFS_QM_QINOCREATE_SPACE_RES(mp) : 0,
                        0, 0, &tp);
        if (error)
                return error;

        if (need_alloc) {
                struct xfs_icreate_args args = {
                        .mode           = S_IFREG,
                        .flags          = XFS_ICREATE_UNLINKABLE,
                };
                xfs_ino_t       ino;

                error = xfs_dialloc(&tp, &args, &ino);
                if (!error)
                        error = xfs_icreate(tp, ino, &args, ipp);
                if (error) {
                        xfs_trans_cancel(tp);
                        return error;
                }
                if (xfs_has_metadir(mp))
                        xfs_metafile_set_iflag(tp, *ipp, metafile_type);
        }

        /*
         * Make the changes in the superblock, and log those too.
         * sbfields arg may contain fields other than *QUOTINO;
         * VERSIONNUM for example.
         */
        spin_lock(&mp->m_sb_lock);
        if (flags & XFS_QMOPT_SBVERSION) {
                ASSERT(!xfs_has_quota(mp));

                xfs_add_quota(mp);
                mp->m_sb.sb_uquotino = NULLFSINO;
                mp->m_sb.sb_gquotino = NULLFSINO;
                mp->m_sb.sb_pquotino = NULLFSINO;

                /* qflags will get updated fully _after_ quotacheck */
                mp->m_sb.sb_qflags = mp->m_qflags & XFS_ALL_QUOTA_ACCT;
        }
        if (flags & XFS_QMOPT_UQUOTA)
                mp->m_sb.sb_uquotino = (*ipp)->i_ino;
        else if (flags & XFS_QMOPT_GQUOTA)
                mp->m_sb.sb_gquotino = (*ipp)->i_ino;
        else
                mp->m_sb.sb_pquotino = (*ipp)->i_ino;
        spin_unlock(&mp->m_sb_lock);
        xfs_log_sb(tp);

        error = xfs_trans_commit(tp);
        if (error) {
                ASSERT(xfs_is_shutdown(mp));
                xfs_alert(mp, "%s failed (error %d)!", __func__, error);
        }
        if (need_alloc) {
                xfs_iunlock(*ipp, XFS_ILOCK_EXCL);
                xfs_finish_inode_setup(*ipp);
        }
        return error;
}


STATIC void
xfs_qm_reset_dqcounts(
        struct xfs_mount        *mp,
        struct xfs_buf          *bp,
        xfs_dqid_t              id,
        xfs_dqtype_t            type)
{
        struct xfs_dqblk        *dqb;
        int                     j;

        trace_xfs_reset_dqcounts(bp, _RET_IP_);

        /*
         * Reset all counters and timers. They'll be
         * started afresh by xfs_qm_quotacheck.
         */
#ifdef DEBUG
        j = (int)XFS_FSB_TO_B(mp, XFS_DQUOT_CLUSTER_SIZE_FSB) /
                sizeof(struct xfs_dqblk);
        ASSERT(mp->m_quotainfo->qi_dqperchunk == j);
#endif
        dqb = bp->b_addr;
        for (j = 0; j < mp->m_quotainfo->qi_dqperchunk; j++) {
                struct xfs_disk_dquot   *ddq;

                ddq = (struct xfs_disk_dquot *)&dqb[j];

                /*
                 * Do a sanity check, and if needed, repair the dqblk. Don't
                 * output any warnings because it's perfectly possible to
                 * find uninitialised dquot blks. See comment in
                 * xfs_dquot_verify.
                 */
                if (xfs_dqblk_verify(mp, &dqb[j], id + j) ||
                    (dqb[j].dd_diskdq.d_type & XFS_DQTYPE_REC_MASK) != type)
                        xfs_dqblk_repair(mp, &dqb[j], id + j, type);

                /*
                 * Reset type in case we are reusing group quota file for
                 * project quotas or vice versa
                 */
                ddq->d_type = type;
                ddq->d_bcount = 0;
                ddq->d_icount = 0;
                ddq->d_rtbcount = 0;

                /*
                 * dquot id 0 stores the default grace period and the maximum
                 * warning limit that were set by the administrator, so we
                 * should not reset them.
                 */
                if (ddq->d_id != 0) {
                        ddq->d_btimer = 0;
                        ddq->d_itimer = 0;
                        ddq->d_rtbtimer = 0;
                        ddq->d_bwarns = 0;
                        ddq->d_iwarns = 0;
                        ddq->d_rtbwarns = 0;
                        if (xfs_has_bigtime(mp))
                                ddq->d_type |= XFS_DQTYPE_BIGTIME;
                }

                if (xfs_has_crc(mp)) {
                        xfs_update_cksum((char *)&dqb[j],
                                         sizeof(struct xfs_dqblk),
                                         XFS_DQUOT_CRC_OFF);
                }
        }
}

STATIC int
xfs_qm_reset_dqcounts_all(
        struct xfs_mount        *mp,
        xfs_dqid_t              firstid,
        xfs_fsblock_t           bno,
        xfs_filblks_t           blkcnt,
        xfs_dqtype_t            type,
        struct list_head        *buffer_list)
{
        struct xfs_buf          *bp;
        int                     error = 0;

        ASSERT(blkcnt > 0);

        /*
         * Blkcnt arg can be a very big number, and might even be
         * larger than the log itself. So, we have to break it up into
         * manageable-sized transactions.
         * Note that we don't start a permanent transaction here; we might
         * not be able to get a log reservation for the whole thing up front,
         * and we don't really care to either, because we just discard
         * everything if we were to crash in the middle of this loop.
         */
        while (blkcnt--) {
                error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
                              XFS_FSB_TO_DADDR(mp, bno),
                              mp->m_quotainfo->qi_dqchunklen, 0, &bp,
                              &xfs_dquot_buf_ops);

                /*
                 * CRC and validation errors will return a EFSCORRUPTED here. If
                 * this occurs, re-read without CRC validation so that we can
                 * repair the damage via xfs_qm_reset_dqcounts(). This process
                 * will leave a trace in the log indicating corruption has
                 * been detected.
                 */
                if (error == -EFSCORRUPTED) {
                        error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
                                      XFS_FSB_TO_DADDR(mp, bno),
                                      mp->m_quotainfo->qi_dqchunklen, 0, &bp,
                                      NULL);
                }

                if (error)
                        break;

                /*
                 * A corrupt buffer might not have a verifier attached, so
                 * make sure we have the correct one attached before writeback
                 * occurs.
                 */
                bp->b_ops = &xfs_dquot_buf_ops;
                xfs_qm_reset_dqcounts(mp, bp, firstid, type);
                xfs_buf_delwri_queue(bp, buffer_list);
                xfs_buf_relse(bp);

                /* goto the next block. */
                bno++;
                firstid += mp->m_quotainfo->qi_dqperchunk;
        }

        return error;
}

/*
 * Iterate over all allocated dquot blocks in this quota inode, zeroing all
 * counters for every chunk of dquots that we find.
 */
STATIC int
xfs_qm_reset_dqcounts_buf(
        struct xfs_mount        *mp,
        struct xfs_inode        *qip,
        xfs_dqtype_t            type,
        struct list_head        *buffer_list)
{
        struct xfs_bmbt_irec    *map;
        int                     i, nmaps;       /* number of map entries */
        int                     error;          /* return value */
        xfs_fileoff_t           lblkno;
        xfs_filblks_t           maxlblkcnt;
        xfs_dqid_t              firstid;
        xfs_fsblock_t           rablkno;
        xfs_filblks_t           rablkcnt;

        error = 0;
        /*
         * This looks racy, but we can't keep an inode lock across a
         * trans_reserve. But, this gets called during quotacheck, and that
         * happens only at mount time which is single threaded.
         */
        if (qip->i_nblocks == 0)
                return 0;

        map = kmalloc(XFS_DQITER_MAP_SIZE * sizeof(*map),
                        GFP_KERNEL | __GFP_NOFAIL);

        lblkno = 0;
        maxlblkcnt = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes);
        do {
                uint            lock_mode;

                nmaps = XFS_DQITER_MAP_SIZE;
                /*
                 * We aren't changing the inode itself. Just changing
                 * some of its data. No new blocks are added here, and
                 * the inode is never added to the transaction.
                 */
                lock_mode = xfs_ilock_data_map_shared(qip);
                error = xfs_bmapi_read(qip, lblkno, maxlblkcnt - lblkno,
                                       map, &nmaps, 0);
                xfs_iunlock(qip, lock_mode);
                if (error)
                        break;

                ASSERT(nmaps <= XFS_DQITER_MAP_SIZE);
                for (i = 0; i < nmaps; i++) {
                        ASSERT(map[i].br_startblock != DELAYSTARTBLOCK);
                        ASSERT(map[i].br_blockcount);


                        lblkno += map[i].br_blockcount;

                        if (map[i].br_startblock == HOLESTARTBLOCK)
                                continue;

                        firstid = (xfs_dqid_t) map[i].br_startoff *
                                mp->m_quotainfo->qi_dqperchunk;
                        /*
                         * Do a read-ahead on the next extent.
                         */
                        if ((i+1 < nmaps) &&
                            (map[i+1].br_startblock != HOLESTARTBLOCK)) {
                                rablkcnt =  map[i+1].br_blockcount;
                                rablkno = map[i+1].br_startblock;
                                while (rablkcnt--) {
                                        xfs_buf_readahead(mp->m_ddev_targp,
                                               XFS_FSB_TO_DADDR(mp, rablkno),
                                               mp->m_quotainfo->qi_dqchunklen,
                                               &xfs_dquot_buf_ops);
                                        rablkno++;
                                }
                        }
                        /*
                         * Iterate thru all the blks in the extent and
                         * reset the counters of all the dquots inside them.
                         */
                        error = xfs_qm_reset_dqcounts_all(mp, firstid,
                                                   map[i].br_startblock,
                                                   map[i].br_blockcount,
                                                   type, buffer_list);
                        if (error)
                                goto out;
                }
        } while (nmaps > 0);

out:
        kfree(map);
        return error;
}

/*
 * Called by dqusage_adjust in doing a quotacheck.
 *
 * Given the inode, and a dquot id this updates both the incore dqout as well
 * as the buffer copy. This is so that once the quotacheck is done, we can
 * just log all the buffers, as opposed to logging numerous updates to
 * individual dquots.
 */
STATIC int
xfs_qm_quotacheck_dqadjust(
        struct xfs_inode        *ip,
        xfs_dqtype_t            type,
        xfs_qcnt_t              nblks,
        xfs_qcnt_t              rtblks)
{
        struct xfs_mount        *mp = ip->i_mount;
        struct xfs_dquot        *dqp;
        xfs_dqid_t              id;
        int                     error;

        id = xfs_qm_id_for_quotatype(ip, type);
        error = xfs_qm_dqget(mp, id, type, true, &dqp);
        if (error) {
                /*
                 * Shouldn't be able to turn off quotas here.
                 */
                ASSERT(error != -ESRCH);
                ASSERT(error != -ENOENT);
                return error;
        }

        mutex_lock(&dqp->q_qlock);
        error = xfs_dquot_attach_buf(NULL, dqp);
        if (error)
                goto out_unlock;

        trace_xfs_dqadjust(dqp);

        /*
         * Adjust the inode count and the block count to reflect this inode's
         * resource usage.
         */
        dqp->q_ino.count++;
        dqp->q_ino.reserved++;
        if (nblks) {
                dqp->q_blk.count += nblks;
                dqp->q_blk.reserved += nblks;
        }
        if (rtblks) {
                dqp->q_rtb.count += rtblks;
                dqp->q_rtb.reserved += rtblks;
        }

        /*
         * Set default limits, adjust timers (since we changed usages)
         *
         * There are no timers for the default values set in the root dquot.
         */
        if (dqp->q_id) {
                xfs_qm_adjust_dqlimits(dqp);
                xfs_qm_adjust_dqtimers(dqp);
        }

        dqp->q_flags |= XFS_DQFLAG_DIRTY;
out_unlock:
        mutex_unlock(&dqp->q_qlock);
        xfs_qm_dqrele(dqp);
        return error;
}

/*
 * callback routine supplied to bulkstat(). Given an inumber, find its
 * dquots and update them to account for resources taken by that inode.
 */
/* ARGSUSED */
STATIC int
xfs_qm_dqusage_adjust(
        struct xfs_mount        *mp,
        struct xfs_trans        *tp,
        xfs_ino_t               ino,
        void                    *data)
{
        struct xfs_inode        *ip;
        xfs_filblks_t           nblks, rtblks;
        unsigned int            lock_mode;
        int                     error;

        ASSERT(XFS_IS_QUOTA_ON(mp));

        /*
         * rootino must have its resources accounted for, not so with the quota
         * inodes.
         */
        if (xfs_is_quota_inode(&mp->m_sb, ino))
                return 0;

        /*
         * We don't _need_ to take the ilock EXCL here because quotacheck runs
         * at mount time and therefore nobody will be racing chown/chproj.
         */
        error = xfs_iget(mp, tp, ino, XFS_IGET_DONTCACHE, 0, &ip);
        if (error == -EINVAL || error == -ENOENT)
                return 0;
        if (error)
                return error;

        /*
         * Reload the incore unlinked list to avoid failure in inodegc.
         * Use an unlocked check here because unrecovered unlinked inodes
         * should be somewhat rare.
         */
        if (xfs_inode_unlinked_incomplete(ip)) {
                error = xfs_inode_reload_unlinked(ip);
                if (error) {
                        xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
                        goto error0;
                }
        }

        /* Metadata directory files are not accounted to user-visible quotas. */
        if (xfs_is_metadir_inode(ip))
                goto error0;

        ASSERT(ip->i_delayed_blks == 0);

        lock_mode = xfs_ilock_data_map_shared(ip);
        if (XFS_IS_REALTIME_INODE(ip)) {
                error = xfs_iread_extents(tp, ip, XFS_DATA_FORK);
                if (error) {
                        xfs_iunlock(ip, lock_mode);
                        goto error0;
                }
        }
        xfs_inode_count_blocks(tp, ip, &nblks, &rtblks);
        xfs_iflags_clear(ip, XFS_IQUOTAUNCHECKED);
        xfs_iunlock(ip, lock_mode);

        /*
         * Add the (disk blocks and inode) resources occupied by this
         * inode to its dquots. We do this adjustment in the incore dquot,
         * and also copy the changes to its buffer.
         * We don't care about putting these changes in a transaction
         * envelope because if we crash in the middle of a 'quotacheck'
         * we have to start from the beginning anyway.
         * Once we're done, we'll log all the dquot bufs.
         *
         * The *QUOTA_ON checks below may look pretty racy, but quotachecks
         * and quotaoffs don't race. (Quotachecks happen at mount time only).
         */
        if (XFS_IS_UQUOTA_ON(mp)) {
                error = xfs_qm_quotacheck_dqadjust(ip, XFS_DQTYPE_USER, nblks,
                                rtblks);
                if (error)
                        goto error0;
        }

        if (XFS_IS_GQUOTA_ON(mp)) {
                error = xfs_qm_quotacheck_dqadjust(ip, XFS_DQTYPE_GROUP, nblks,
                                rtblks);
                if (error)
                        goto error0;
        }

        if (XFS_IS_PQUOTA_ON(mp)) {
                error = xfs_qm_quotacheck_dqadjust(ip, XFS_DQTYPE_PROJ, nblks,
                                rtblks);
                if (error)
                        goto error0;
        }

error0:
        xfs_irele(ip);
        return error;
}

STATIC int
xfs_qm_flush_one(
        struct xfs_dquot        *dqp,
        void                    *data)
{
        struct list_head        *buffer_list = data;
        struct xfs_buf          *bp = NULL;
        int                     error = 0;

        if (!lockref_get_not_dead(&dqp->q_lockref))
                return 0;

        mutex_lock(&dqp->q_qlock);
        if (!XFS_DQ_IS_DIRTY(dqp))
                goto out_unlock;

        xfs_qm_dqunpin_wait(dqp);
        xfs_dqflock(dqp);

        error = xfs_dquot_use_attached_buf(dqp, &bp);
        if (error)
                goto out_unlock;
        if (!bp) {
                error = -EFSCORRUPTED;
                goto out_unlock;
        }

        error = xfs_qm_dqflush(dqp, bp);
        if (!error)
                xfs_buf_delwri_queue(bp, buffer_list);
        xfs_buf_relse(bp);
out_unlock:
        mutex_unlock(&dqp->q_qlock);
        xfs_qm_dqrele(dqp);
        return error;
}

/*
 * Walk thru all the filesystem inodes and construct a consistent view
 * of the disk quota world. If the quotacheck fails, disable quotas.
 */
STATIC int
xfs_qm_quotacheck(
        xfs_mount_t     *mp)
{
        int                     error, error2;
        uint                    flags;
        LIST_HEAD               (buffer_list);
        struct xfs_inode        *uip = mp->m_quotainfo->qi_uquotaip;
        struct xfs_inode        *gip = mp->m_quotainfo->qi_gquotaip;
        struct xfs_inode        *pip = mp->m_quotainfo->qi_pquotaip;

        flags = 0;

        ASSERT(uip || gip || pip);
        ASSERT(XFS_IS_QUOTA_ON(mp));

        xfs_notice(mp, "Quotacheck needed: Please wait.");

        /*
         * First we go thru all the dquots on disk, USR and GRP/PRJ, and reset
         * their counters to zero. We need a clean slate.
         * We don't log our changes till later.
         */
        if (uip) {
                error = xfs_qm_reset_dqcounts_buf(mp, uip, XFS_DQTYPE_USER,
                                         &buffer_list);
                if (error)
                        goto error_return;
                flags |= XFS_UQUOTA_CHKD;
        }

        if (gip) {
                error = xfs_qm_reset_dqcounts_buf(mp, gip, XFS_DQTYPE_GROUP,
                                         &buffer_list);
                if (error)
                        goto error_return;
                flags |= XFS_GQUOTA_CHKD;
        }

        if (pip) {
                error = xfs_qm_reset_dqcounts_buf(mp, pip, XFS_DQTYPE_PROJ,
                                         &buffer_list);
                if (error)
                        goto error_return;
                flags |= XFS_PQUOTA_CHKD;
        }

        xfs_set_quotacheck_running(mp);
        error = xfs_iwalk_threaded(mp, 0, 0, xfs_qm_dqusage_adjust, 0, true,
                        NULL);
        xfs_clear_quotacheck_running(mp);

        /*
         * On error, the inode walk may have partially populated the dquot
         * caches.  We must purge them before disabling quota and tearing down
         * the quotainfo, or else the dquots will leak.
         */
        if (error)
                goto error_purge;

        /*
         * We've made all the changes that we need to make incore.  Flush them
         * down to disk buffers if everything was updated successfully.
         */
        if (XFS_IS_UQUOTA_ON(mp)) {
                error = xfs_qm_dquot_walk(mp, XFS_DQTYPE_USER, xfs_qm_flush_one,
                                          &buffer_list);
        }
        if (XFS_IS_GQUOTA_ON(mp)) {
                error2 = xfs_qm_dquot_walk(mp, XFS_DQTYPE_GROUP, xfs_qm_flush_one,
                                           &buffer_list);
                if (!error)
                        error = error2;
        }
        if (XFS_IS_PQUOTA_ON(mp)) {
                error2 = xfs_qm_dquot_walk(mp, XFS_DQTYPE_PROJ, xfs_qm_flush_one,
                                           &buffer_list);
                if (!error)
                        error = error2;
        }

        error2 = xfs_buf_delwri_submit(&buffer_list);
        if (!error)
                error = error2;

        /*
         * We can get this error if we couldn't do a dquot allocation inside
         * xfs_qm_dqusage_adjust (via bulkstat). We don't care about the
         * dirty dquots that might be cached, we just want to get rid of them
         * and turn quotaoff. The dquots won't be attached to any of the inodes
         * at this point (because we intentionally didn't in dqget_noattach).
         */
        if (error)
                goto error_purge;

        /*
         * If one type of quotas is off, then it will lose its
         * quotachecked status, since we won't be doing accounting for
         * that type anymore.
         */
        mp->m_qflags &= ~XFS_ALL_QUOTA_CHKD;
        mp->m_qflags |= flags;

error_return:
        xfs_buf_delwri_cancel(&buffer_list);

        if (error) {
                xfs_warn(mp,
        "Quotacheck: Unsuccessful (Error %d): Disabling quotas.",
                        error);
                /*
                 * We must turn off quotas.
                 */
                ASSERT(mp->m_quotainfo != NULL);
                xfs_qm_destroy_quotainfo(mp);
                if (xfs_mount_reset_sbqflags(mp)) {
                        xfs_warn(mp,
                                "Quotacheck: Failed to reset quota flags.");
                }
                xfs_fs_mark_sick(mp, XFS_SICK_FS_QUOTACHECK);
        } else {
                xfs_notice(mp, "Quotacheck: Done.");
                xfs_fs_mark_healthy(mp, XFS_SICK_FS_QUOTACHECK);
        }

        return error;

error_purge:
        /*
         * On error, we may have inodes queued for inactivation. This may try
         * to attach dquots to the inode before running cleanup operations on
         * the inode and this can race with the xfs_qm_destroy_quotainfo() call
         * below that frees mp->m_quotainfo. To avoid this race, flush all the
         * pending inodegc operations before we purge the dquots from memory,
         * ensuring that background inactivation is idle whilst we turn off
         * quotas.
         */
        xfs_inodegc_flush(mp);
        xfs_qm_dqpurge_all(mp);
        goto error_return;

}

/*
 * This is called from xfs_mountfs to start quotas and initialize all
 * necessary data structures like quotainfo.  This is also responsible for
 * running a quotacheck as necessary.  We are guaranteed that the superblock
 * is consistently read in at this point.
 *
 * If we fail here, the mount will continue with quota turned off. We don't
 * need to inidicate success or failure at all.
 */
void
xfs_qm_mount_quotas(
        struct xfs_mount        *mp)
{
        int                     error = 0;
        uint                    sbf;

        /*
         * If quotas on realtime volumes is not supported, disable quotas
         * immediately.  We only support rtquota if rtgroups are enabled to
         * avoid problems with older kernels.
         */
        if (mp->m_sb.sb_rextents &&
            (!xfs_has_rtgroups(mp) || xfs_has_zoned(mp))) {
                xfs_notice(mp, "Cannot turn on quotas for realtime filesystem");
                mp->m_qflags = 0;
                goto write_changes;
        }

        ASSERT(XFS_IS_QUOTA_ON(mp));

        /*
         * Allocate the quotainfo structure inside the mount struct, and
         * create quotainode(s), and change/rev superblock if necessary.
         */
        error = xfs_qm_init_quotainfo(mp);
        if (error) {
                /*
                 * We must turn off quotas.
                 */
                ASSERT(mp->m_quotainfo == NULL);
                mp->m_qflags = 0;
                goto write_changes;
        }
        /*
         * If any of the quotas are not consistent, do a quotacheck.
         */
        if (XFS_QM_NEED_QUOTACHECK(mp)) {
                error = xfs_qm_quotacheck(mp);
                if (error) {
                        /* Quotacheck failed and disabled quotas. */
                        return;
                }
        }
        /*
         * If one type of quotas is off, then it will lose its
         * quotachecked status, since we won't be doing accounting for
         * that type anymore.
         */
        if (!XFS_IS_UQUOTA_ON(mp))
                mp->m_qflags &= ~XFS_UQUOTA_CHKD;
        if (!XFS_IS_GQUOTA_ON(mp))
                mp->m_qflags &= ~XFS_GQUOTA_CHKD;
        if (!XFS_IS_PQUOTA_ON(mp))
                mp->m_qflags &= ~XFS_PQUOTA_CHKD;

 write_changes:
        /*
         * We actually don't have to acquire the m_sb_lock at all.
         * This can only be called from mount, and that's single threaded. XXX
         */
        spin_lock(&mp->m_sb_lock);
        sbf = mp->m_sb.sb_qflags;
        mp->m_sb.sb_qflags = mp->m_qflags & XFS_MOUNT_QUOTA_ALL;
        spin_unlock(&mp->m_sb_lock);

        if (sbf != (mp->m_qflags & XFS_MOUNT_QUOTA_ALL)) {
                if (xfs_sync_sb(mp, false)) {
                        /*
                         * We could only have been turning quotas off.
                         * We aren't in very good shape actually because
                         * the incore structures are convinced that quotas are
                         * off, but the on disk superblock doesn't know that !
                         */
                        ASSERT(!(XFS_IS_QUOTA_ON(mp)));
                        xfs_alert(mp, "%s: Superblock update failed!",
                                __func__);
                }
        }

        if (error) {
                xfs_warn(mp, "Failed to initialize disk quotas, err %d.", error);
                return;
        }
}

/*
 * Load the inode for a given type of quota, assuming that the sb fields have
 * been sorted out.  This is not true when switching quota types on a V4
 * filesystem, so do not use this function for that.
 *
 * Returns -ENOENT if the quota inode field is NULLFSINO; 0 and an inode on
 * success; or a negative errno.
 */
int
xfs_qm_qino_load(
        struct xfs_mount        *mp,
        xfs_dqtype_t            type,
        struct xfs_inode        **ipp)
{
        struct xfs_trans        *tp;
        struct xfs_inode        *dp = NULL;
        int                     error;

        tp = xfs_trans_alloc_empty(mp);
        if (xfs_has_metadir(mp)) {
                error = xfs_dqinode_load_parent(tp, &dp);
                if (error)
                        goto out_cancel;
        }

        error = xfs_dqinode_load(tp, dp, type, ipp);
        if (dp)
                xfs_irele(dp);
out_cancel:
        xfs_trans_cancel(tp);
        return error;
}

/*
 * This is called after the superblock has been read in and we're ready to
 * iget the quota inodes.
 */
STATIC int
xfs_qm_init_quotainos(
        xfs_mount_t     *mp)
{
        struct xfs_inode        *uip = NULL;
        struct xfs_inode        *gip = NULL;
        struct xfs_inode        *pip = NULL;
        int                     error;
        uint                    flags = 0;

        ASSERT(mp->m_quotainfo);

        /*
         * Get the uquota and gquota inodes
         */
        if (xfs_has_quota(mp)) {
                if (XFS_IS_UQUOTA_ON(mp) &&
                    mp->m_sb.sb_uquotino != NULLFSINO) {
                        ASSERT(mp->m_sb.sb_uquotino > 0);
                        error = xfs_qm_qino_load(mp, XFS_DQTYPE_USER, &uip);
                        if (error)
                                return error;
                }
                if (XFS_IS_GQUOTA_ON(mp) &&
                    mp->m_sb.sb_gquotino != NULLFSINO) {
                        ASSERT(mp->m_sb.sb_gquotino > 0);
                        error = xfs_qm_qino_load(mp, XFS_DQTYPE_GROUP, &gip);
                        if (error)
                                goto error_rele;
                }
                if (XFS_IS_PQUOTA_ON(mp) &&
                    mp->m_sb.sb_pquotino != NULLFSINO) {
                        ASSERT(mp->m_sb.sb_pquotino > 0);
                        error = xfs_qm_qino_load(mp, XFS_DQTYPE_PROJ, &pip);
                        if (error)
                                goto error_rele;
                }
        } else {
                flags |= XFS_QMOPT_SBVERSION;
        }

        /*
         * Create the three inodes, if they don't exist already. The changes
         * made above will get added to a transaction and logged in one of
         * the qino_alloc calls below.  If the device is readonly,
         * temporarily switch to read-write to do this.
         */
        if (XFS_IS_UQUOTA_ON(mp) && uip == NULL) {
                error = xfs_qm_qino_alloc(mp, &uip,
                                              flags | XFS_QMOPT_UQUOTA);
                if (error)
                        goto error_rele;

                flags &= ~XFS_QMOPT_SBVERSION;
        }
        if (XFS_IS_GQUOTA_ON(mp) && gip == NULL) {
                error = xfs_qm_qino_alloc(mp, &gip,
                                          flags | XFS_QMOPT_GQUOTA);
                if (error)
                        goto error_rele;

                flags &= ~XFS_QMOPT_SBVERSION;
        }
        if (XFS_IS_PQUOTA_ON(mp) && pip == NULL) {
                error = xfs_qm_qino_alloc(mp, &pip,
                                          flags | XFS_QMOPT_PQUOTA);
                if (error)
                        goto error_rele;
        }

        mp->m_quotainfo->qi_uquotaip = uip;
        mp->m_quotainfo->qi_gquotaip = gip;
        mp->m_quotainfo->qi_pquotaip = pip;

        return 0;

error_rele:
        if (uip)
                xfs_irele(uip);
        if (gip)
                xfs_irele(gip);
        if (pip)
                xfs_irele(pip);
        return error;
}

STATIC void
xfs_qm_dqfree_one(
        struct xfs_dquot        *dqp)
{
        struct xfs_mount        *mp = dqp->q_mount;
        struct xfs_quotainfo    *qi = mp->m_quotainfo;

        mutex_lock(&qi->qi_tree_lock);
        radix_tree_delete(xfs_dquot_tree(qi, xfs_dquot_type(dqp)), dqp->q_id);

        qi->qi_dquots--;
        mutex_unlock(&qi->qi_tree_lock);

        xfs_qm_dqdestroy(dqp);
}

/* --------------- utility functions for vnodeops ---------------- */


/*
 * Given an inode, a uid, gid and prid make sure that we have
 * allocated relevant dquot(s) on disk, and that we won't exceed inode
 * quotas by creating this file.
 * This also attaches dquot(s) to the given inode after locking it,
 * and returns the dquots corresponding to the uid and/or gid.
 *
 * in   : inode (unlocked)
 * out  : udquot, gdquot with references taken and unlocked
 */
int
xfs_qm_vop_dqalloc(
        struct xfs_inode        *ip,
        kuid_t                  uid,
        kgid_t                  gid,
        prid_t                  prid,
        uint                    flags,
        struct xfs_dquot        **O_udqpp,
        struct xfs_dquot        **O_gdqpp,
        struct xfs_dquot        **O_pdqpp)
{
        struct xfs_mount        *mp = ip->i_mount;
        struct inode            *inode = VFS_I(ip);
        struct user_namespace   *user_ns = inode->i_sb->s_user_ns;
        struct xfs_dquot        *uq = NULL;
        struct xfs_dquot        *gq = NULL;
        struct xfs_dquot        *pq = NULL;
        int                     error;

        if (!XFS_IS_QUOTA_ON(mp))
                return 0;

        ASSERT(!xfs_is_metadir_inode(ip));

        if ((flags & XFS_QMOPT_INHERIT) && XFS_INHERIT_GID(ip))
                gid = inode->i_gid;

        /*
         * Attach the dquot(s) to this inode, doing a dquot allocation
         * if necessary. The dquot(s) will not be locked.
         */
        if (XFS_NOT_DQATTACHED(mp, ip)) {
                xfs_ilock(ip, XFS_ILOCK_EXCL);
                error = xfs_qm_dqattach_locked(ip, true);
                xfs_iunlock(ip, XFS_ILOCK_EXCL);
                if (error)
                        return error;
        }

        if ((flags & XFS_QMOPT_UQUOTA) && XFS_IS_UQUOTA_ON(mp)) {
                ASSERT(O_udqpp);
                if (!uid_eq(inode->i_uid, uid)) {
                        error = xfs_qm_dqget(mp, from_kuid(user_ns, uid),
                                        XFS_DQTYPE_USER, true, &uq);
                        if (error) {
                                ASSERT(error != -ENOENT);
                                return error;
                        }
                } else {
                        /*
                         * Take an extra reference, because we'll return
                         * this to caller
                         */
                        ASSERT(ip->i_udquot);
                        uq = xfs_qm_dqhold(ip->i_udquot);
                }
        }
        if ((flags & XFS_QMOPT_GQUOTA) && XFS_IS_GQUOTA_ON(mp)) {
                ASSERT(O_gdqpp);
                if (!gid_eq(inode->i_gid, gid)) {
                        error = xfs_qm_dqget(mp, from_kgid(user_ns, gid),
                                        XFS_DQTYPE_GROUP, true, &gq);
                        if (error) {
                                ASSERT(error != -ENOENT);
                                goto error_rele;
                        }
                } else {
                        ASSERT(ip->i_gdquot);
                        gq = xfs_qm_dqhold(ip->i_gdquot);
                }
        }
        if ((flags & XFS_QMOPT_PQUOTA) && XFS_IS_PQUOTA_ON(mp)) {
                ASSERT(O_pdqpp);
                if (ip->i_projid != prid) {
                        error = xfs_qm_dqget(mp, prid,
                                        XFS_DQTYPE_PROJ, true, &pq);
                        if (error) {
                                ASSERT(error != -ENOENT);
                                goto error_rele;
                        }
                } else {
                        ASSERT(ip->i_pdquot);
                        pq = xfs_qm_dqhold(ip->i_pdquot);
                }
        }
        trace_xfs_dquot_dqalloc(ip);

        if (O_udqpp)
                *O_udqpp = uq;
        else
                xfs_qm_dqrele(uq);
        if (O_gdqpp)
                *O_gdqpp = gq;
        else
                xfs_qm_dqrele(gq);
        if (O_pdqpp)
                *O_pdqpp = pq;
        else
                xfs_qm_dqrele(pq);
        return 0;

error_rele:
        xfs_qm_dqrele(gq);
        xfs_qm_dqrele(uq);
        return error;
}

/*
 * Actually transfer ownership, and do dquot modifications.
 * These were already reserved.
 */
struct xfs_dquot *
xfs_qm_vop_chown(
        struct xfs_trans        *tp,
        struct xfs_inode        *ip,
        struct xfs_dquot        **IO_olddq,
        struct xfs_dquot        *newdq)
{
        struct xfs_dquot        *prevdq;
        xfs_filblks_t           dblocks, rblocks;
        bool                    isrt = XFS_IS_REALTIME_INODE(ip);

        xfs_assert_ilocked(ip, XFS_ILOCK_EXCL);
        ASSERT(XFS_IS_QUOTA_ON(ip->i_mount));
        ASSERT(!xfs_is_metadir_inode(ip));

        /* old dquot */
        prevdq = *IO_olddq;
        ASSERT(prevdq);
        ASSERT(prevdq != newdq);

        xfs_inode_count_blocks(tp, ip, &dblocks, &rblocks);

        xfs_trans_mod_ino_dquot(tp, ip, prevdq, XFS_TRANS_DQ_BCOUNT,
                        -(xfs_qcnt_t)dblocks);
        xfs_trans_mod_ino_dquot(tp, ip, prevdq, XFS_TRANS_DQ_RTBCOUNT,
                        -(xfs_qcnt_t)rblocks);
        xfs_trans_mod_ino_dquot(tp, ip, prevdq, XFS_TRANS_DQ_ICOUNT, -1);

        /* the sparkling new dquot */
        xfs_trans_mod_ino_dquot(tp, ip, newdq, XFS_TRANS_DQ_BCOUNT, dblocks);
        xfs_trans_mod_ino_dquot(tp, ip, newdq, XFS_TRANS_DQ_RTBCOUNT, rblocks);
        xfs_trans_mod_ino_dquot(tp, ip, newdq, XFS_TRANS_DQ_ICOUNT, 1);

        /*
         * Back when we made quota reservations for the chown, we reserved the
         * ondisk blocks + delalloc blocks with the new dquot.  Now that we've
         * switched the dquots, decrease the new dquot's block reservation
         * (having already bumped up the real counter) so that we don't have
         * any reservation to give back when we commit.
         */
        xfs_trans_mod_dquot(tp, newdq,
                        isrt ? XFS_TRANS_DQ_RES_RTBLKS : XFS_TRANS_DQ_RES_BLKS,
                        -ip->i_delayed_blks);

        /*
         * Give the incore reservation for delalloc blocks back to the old
         * dquot.  We don't normally handle delalloc quota reservations
         * transactionally, so just lock the dquot and subtract from the
         * reservation.  Dirty the transaction because it's too late to turn
         * back now.
         */
        tp->t_flags |= XFS_TRANS_DIRTY;
        mutex_lock(&prevdq->q_qlock);
        if (isrt) {
                ASSERT(prevdq->q_rtb.reserved >= ip->i_delayed_blks);
                prevdq->q_rtb.reserved -= ip->i_delayed_blks;
        } else {
                ASSERT(prevdq->q_blk.reserved >= ip->i_delayed_blks);
                prevdq->q_blk.reserved -= ip->i_delayed_blks;
        }
        mutex_unlock(&prevdq->q_qlock);

        /*
         * Take an extra reference, because the inode is going to keep
         * this dquot pointer even after the trans_commit.
         */
        *IO_olddq = xfs_qm_dqhold(newdq);

        return prevdq;
}

int
xfs_qm_vop_rename_dqattach(
        struct xfs_inode        **i_tab)
{
        struct xfs_mount        *mp = i_tab[0]->i_mount;
        int                     i;

        if (!XFS_IS_QUOTA_ON(mp))
                return 0;

        for (i = 0; (i < 4 && i_tab[i]); i++) {
                struct xfs_inode        *ip = i_tab[i];
                int                     error;

                /*
                 * Watch out for duplicate entries in the table.
                 */
                if (i == 0 || ip != i_tab[i-1]) {
                        if (XFS_NOT_DQATTACHED(mp, ip)) {
                                error = xfs_qm_dqattach(ip);
                                if (error)
                                        return error;
                        }
                }
        }
        return 0;
}

void
xfs_qm_vop_create_dqattach(
        struct xfs_trans        *tp,
        struct xfs_inode        *ip,
        struct xfs_dquot        *udqp,
        struct xfs_dquot        *gdqp,
        struct xfs_dquot        *pdqp)
{
        struct xfs_mount        *mp = tp->t_mountp;

        if (!XFS_IS_QUOTA_ON(mp))
                return;

        xfs_assert_ilocked(ip, XFS_ILOCK_EXCL);
        ASSERT(!xfs_is_metadir_inode(ip));

        if (udqp && XFS_IS_UQUOTA_ON(mp)) {
                ASSERT(ip->i_udquot == NULL);
                ASSERT(i_uid_read(VFS_I(ip)) == udqp->q_id);

                ip->i_udquot = xfs_qm_dqhold(udqp);
        }
        if (gdqp && XFS_IS_GQUOTA_ON(mp)) {
                ASSERT(ip->i_gdquot == NULL);
                ASSERT(i_gid_read(VFS_I(ip)) == gdqp->q_id);

                ip->i_gdquot = xfs_qm_dqhold(gdqp);
        }
        if (pdqp && XFS_IS_PQUOTA_ON(mp)) {
                ASSERT(ip->i_pdquot == NULL);
                ASSERT(ip->i_projid == pdqp->q_id);

                ip->i_pdquot = xfs_qm_dqhold(pdqp);
        }

        xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_ICOUNT, 1);
}

/* Decide if this inode's dquot is near an enforcement boundary. */
bool
xfs_inode_near_dquot_enforcement(
        struct xfs_inode        *ip,
        xfs_dqtype_t            type)
{
        struct xfs_dquot        *dqp;
        struct xfs_dquot_res    *res;
        struct xfs_dquot_pre    *pre;
        int64_t                 freesp;

        /* We only care for quotas that are enabled and enforced. */
        dqp = xfs_inode_dquot(ip, type);
        if (!dqp || !xfs_dquot_is_enforced(dqp))
                return false;

        if (xfs_dquot_res_over_limits(&dqp->q_ino) ||
            xfs_dquot_res_over_limits(&dqp->q_blk) ||
            xfs_dquot_res_over_limits(&dqp->q_rtb))
                return true;

        if (XFS_IS_REALTIME_INODE(ip)) {
                res = &dqp->q_rtb;
                pre = &dqp->q_rtb_prealloc;
        } else {
                res = &dqp->q_blk;
                pre = &dqp->q_blk_prealloc;
        }

        /* For space on the data device, check the various thresholds. */
        if (!pre->q_prealloc_hi_wmark)
                return false;

        if (res->reserved < pre->q_prealloc_lo_wmark)
                return false;

        if (res->reserved >= pre->q_prealloc_hi_wmark)
                return true;

        freesp = pre->q_prealloc_hi_wmark - res->reserved;
        if (freesp < pre->q_low_space[XFS_QLOWSP_5_PCNT])
                return true;

        return false;
}