// 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_sb.h"
#include "xfs_mount.h"
#include "xfs_trans.h"
#include "xfs_error.h"
#include "xfs_alloc.h"
#include "xfs_fsops.h"
#include "xfs_trans_space.h"
#include "xfs_log.h"
#include "xfs_log_priv.h"
#include "xfs_ag.h"
#include "xfs_ag_resv.h"
#include "xfs_trace.h"
#include "xfs_rtalloc.h"
#include "xfs_rtrmap_btree.h"
#include "xfs_rtrefcount_btree.h"
#include "xfs_metafile.h"
#include "xfs_healthmon.h"

#include <linux/fserror.h>

/*
 * Write new AG headers to disk. Non-transactional, but need to be
 * written and completed prior to the growfs transaction being logged.
 * To do this, we use a delayed write buffer list and wait for
 * submission and IO completion of the list as a whole. This allows the
 * IO subsystem to merge all the AG headers in a single AG into a single
 * IO and hide most of the latency of the IO from us.
 *
 * This also means that if we get an error whilst building the buffer
 * list to write, we can cancel the entire list without having written
 * anything.
 */
static int
xfs_resizefs_init_new_ags(
        struct xfs_trans        *tp,
        struct aghdr_init_data  *id,
        xfs_agnumber_t          oagcount,
        xfs_agnumber_t          nagcount,
        xfs_rfsblock_t          delta,
        struct xfs_perag        *last_pag,
        bool                    *lastag_extended)
{
        struct xfs_mount        *mp = tp->t_mountp;
        xfs_rfsblock_t          nb = mp->m_sb.sb_dblocks + delta;
        int                     error;

        *lastag_extended = false;

        INIT_LIST_HEAD(&id->buffer_list);
        for (id->agno = nagcount - 1;
             id->agno >= oagcount;
             id->agno--, delta -= id->agsize) {

                if (id->agno == nagcount - 1)
                        id->agsize = nb - (id->agno *
                                        (xfs_rfsblock_t)mp->m_sb.sb_agblocks);
                else
                        id->agsize = mp->m_sb.sb_agblocks;

                error = xfs_ag_init_headers(mp, id);
                if (error) {
                        xfs_buf_delwri_cancel(&id->buffer_list);
                        return error;
                }
        }

        error = xfs_buf_delwri_submit(&id->buffer_list);
        if (error)
                return error;

        if (delta) {
                *lastag_extended = true;
                error = xfs_ag_extend_space(last_pag, tp, delta);
        }
        return error;
}

/*
 * growfs operations
 */
static int
xfs_growfs_data_private(
        struct xfs_mount        *mp,            /* mount point for filesystem */
        struct xfs_growfs_data  *in)            /* growfs data input struct */
{
        xfs_agnumber_t          oagcount = mp->m_sb.sb_agcount;
        xfs_rfsblock_t          nb = in->newblocks;
        struct xfs_buf          *bp;
        int                     error;
        xfs_agnumber_t          nagcount;
        xfs_agnumber_t          nagimax = 0;
        int64_t                 delta;
        bool                    lastag_extended = false;
        struct xfs_trans        *tp;
        struct aghdr_init_data  id = {};
        struct xfs_perag        *last_pag;

        error = xfs_sb_validate_fsb_count(&mp->m_sb, nb);
        if (error)
                return error;

        if (nb > mp->m_sb.sb_dblocks) {
                error = xfs_buf_read_uncached(mp->m_ddev_targp,
                                XFS_FSB_TO_BB(mp, nb) - XFS_FSS_TO_BB(mp, 1),
                                XFS_FSS_TO_BB(mp, 1), &bp, NULL);
                if (error)
                        return error;
                xfs_buf_relse(bp);
        }

        /* Make sure the new fs size won't cause problems with the log. */
        error = xfs_growfs_check_rtgeom(mp, nb, mp->m_sb.sb_rblocks,
                        mp->m_sb.sb_rextsize);
        if (error)
                return error;
        xfs_growfs_compute_deltas(mp, nb, &delta, &nagcount);

        /*
         * Reject filesystems with a single AG because they are not
         * supported, and reject a shrink operation that would cause a
         * filesystem to become unsupported.
         */
        if (delta < 0 && nagcount < 2)
                return -EINVAL;

        /* No work to do */
        if (delta == 0)
                return 0;

        /* TODO: shrinking the entire AGs hasn't yet completed */
        if (nagcount < oagcount)
                return -EINVAL;

        /* allocate the new per-ag structures */
        error = xfs_initialize_perag(mp, oagcount, nagcount, nb, &nagimax);
        if (error)
                return error;

        if (delta > 0)
                error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growdata,
                                XFS_GROWFS_SPACE_RES(mp), 0, XFS_TRANS_RESERVE,
                                &tp);
        else
                error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growdata, -delta, 0,
                                0, &tp);
        if (error)
                goto out_free_unused_perag;

        last_pag = xfs_perag_get(mp, oagcount - 1);
        if (delta > 0) {
                error = xfs_resizefs_init_new_ags(tp, &id, oagcount, nagcount,
                                delta, last_pag, &lastag_extended);
        } else {
                xfs_warn_experimental(mp, XFS_EXPERIMENTAL_SHRINK);
                error = xfs_ag_shrink_space(last_pag, &tp, -delta);
        }
        xfs_perag_put(last_pag);
        if (error)
                goto out_trans_cancel;

        /*
         * Update changed superblock fields transactionally. These are not
         * seen by the rest of the world until the transaction commit applies
         * them atomically to the superblock.
         */
        if (nagcount > oagcount)
                xfs_trans_mod_sb(tp, XFS_TRANS_SB_AGCOUNT, nagcount - oagcount);
        if (delta)
                xfs_trans_mod_sb(tp, XFS_TRANS_SB_DBLOCKS, delta);
        if (id.nfree)
                xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, id.nfree);

        /*
         * Sync sb counters now to reflect the updated values. This is
         * particularly important for shrink because the write verifier
         * will fail if sb_fdblocks is ever larger than sb_dblocks.
         */
        if (xfs_has_lazysbcount(mp))
                xfs_log_sb(tp);

        xfs_trans_set_sync(tp);
        error = xfs_trans_commit(tp);
        if (error)
                return error;

        /* New allocation groups fully initialized, so update mount struct */
        if (nagimax)
                mp->m_maxagi = nagimax;
        xfs_set_low_space_thresholds(mp);
        mp->m_alloc_set_aside = xfs_alloc_set_aside(mp);

        if (delta > 0) {
                /*
                 * If we expanded the last AG, free the per-AG reservation
                 * so we can reinitialize it with the new size.
                 */
                if (lastag_extended) {
                        struct xfs_perag        *pag;

                        pag = xfs_perag_get(mp, id.agno);
                        xfs_ag_resv_free(pag);
                        xfs_perag_put(pag);
                }
                /*
                 * Reserve AG metadata blocks. ENOSPC here does not mean there
                 * was a growfs failure, just that there still isn't space for
                 * new user data after the grow has been run.
                 */
                error = xfs_fs_reserve_ag_blocks(mp);
                if (error == -ENOSPC)
                        error = 0;

                /* Compute new maxlevels for rt btrees. */
                xfs_rtrmapbt_compute_maxlevels(mp);
                xfs_rtrefcountbt_compute_maxlevels(mp);
        }

        return error;

out_trans_cancel:
        xfs_trans_cancel(tp);
out_free_unused_perag:
        if (nagcount > oagcount)
                xfs_free_perag_range(mp, oagcount, nagcount);
        return error;
}

static int
xfs_growfs_log_private(
        struct xfs_mount        *mp,    /* mount point for filesystem */
        struct xfs_growfs_log   *in)    /* growfs log input struct */
{
        xfs_extlen_t            nb;

        nb = in->newblocks;
        if (nb < XFS_MIN_LOG_BLOCKS || nb < XFS_B_TO_FSB(mp, XFS_MIN_LOG_BYTES))
                return -EINVAL;
        if (nb == mp->m_sb.sb_logblocks &&
            in->isint == (mp->m_sb.sb_logstart != 0))
                return -EINVAL;
        /*
         * Moving the log is hard, need new interfaces to sync
         * the log first, hold off all activity while moving it.
         * Can have shorter or longer log in the same space,
         * or transform internal to external log or vice versa.
         */
        return -ENOSYS;
}

static int
xfs_growfs_imaxpct(
        struct xfs_mount        *mp,
        __u32                   imaxpct)
{
        struct xfs_trans        *tp;
        int                     dpct;
        int                     error;

        if (imaxpct > 100)
                return -EINVAL;

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

        dpct = imaxpct - mp->m_sb.sb_imax_pct;
        xfs_trans_mod_sb(tp, XFS_TRANS_SB_IMAXPCT, dpct);
        xfs_trans_set_sync(tp);
        return xfs_trans_commit(tp);
}

/*
 * protected versions of growfs function acquire and release locks on the mount
 * point - exported through ioctls: XFS_IOC_FSGROWFSDATA, XFS_IOC_FSGROWFSLOG,
 * XFS_IOC_FSGROWFSRT
 */
int
xfs_growfs_data(
        struct xfs_mount        *mp,
        struct xfs_growfs_data  *in)
{
        int                     error;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;
        if (!mutex_trylock(&mp->m_growlock))
                return -EWOULDBLOCK;

        /* we can't grow the data section when an internal RT section exists */
        if (in->newblocks != mp->m_sb.sb_dblocks && mp->m_sb.sb_rtstart) {
                error = -EINVAL;
                goto out_unlock;
        }

        /* update imaxpct separately to the physical grow of the filesystem */
        if (in->imaxpct != mp->m_sb.sb_imax_pct) {
                error = xfs_growfs_imaxpct(mp, in->imaxpct);
                if (error)
                        goto out_unlock;
        }

        if (in->newblocks != mp->m_sb.sb_dblocks) {
                error = xfs_growfs_data_private(mp, in);
                if (error)
                        goto out_unlock;
        }

        /* Post growfs calculations needed to reflect new state in operations */
        if (mp->m_sb.sb_imax_pct) {
                uint64_t icount = mp->m_sb.sb_dblocks * mp->m_sb.sb_imax_pct;
                do_div(icount, 100);
                M_IGEO(mp)->maxicount = XFS_FSB_TO_INO(mp, icount);
        } else
                M_IGEO(mp)->maxicount = 0;

        /* Update secondary superblocks now the physical grow has completed */
        error = xfs_update_secondary_sbs(mp);

        /*
         * Increment the generation unconditionally, after trying to update the
         * secondary superblocks, as the new size is live already at this point.
         */
        mp->m_generation++;
out_unlock:
        mutex_unlock(&mp->m_growlock);
        return error;
}

int
xfs_growfs_log(
        xfs_mount_t             *mp,
        struct xfs_growfs_log   *in)
{
        int error;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;
        if (!mutex_trylock(&mp->m_growlock))
                return -EWOULDBLOCK;
        error = xfs_growfs_log_private(mp, in);
        mutex_unlock(&mp->m_growlock);
        return error;
}

/*
 * Reserve the requested number of blocks if available. Otherwise return
 * as many as possible to satisfy the request. The actual number
 * reserved are returned in outval.
 */
int
xfs_reserve_blocks(
        struct xfs_mount        *mp,
        enum xfs_free_counter   ctr,
        uint64_t                request)
{
        int64_t                 lcounter, delta;
        int64_t                 fdblks_delta = 0;
        int64_t                 free;
        int                     error = 0;

        ASSERT(ctr < XC_FREE_NR);

        /*
         * With per-cpu counters, this becomes an interesting problem. we need
         * to work out if we are freeing or allocation blocks first, then we can
         * do the modification as necessary.
         *
         * We do this under the m_sb_lock so that if we are near ENOSPC, we will
         * hold out any changes while we work out what to do. This means that
         * the amount of free space can change while we do this, so we need to
         * retry if we end up trying to reserve more space than is available.
         */
        spin_lock(&mp->m_sb_lock);

        /*
         * If our previous reservation was larger than the current value,
         * then move any unused blocks back to the free pool. Modify the resblks
         * counters directly since we shouldn't have any problems unreserving
         * space.
         */
        if (mp->m_free[ctr].res_total > request) {
                lcounter = mp->m_free[ctr].res_avail - request;
                if (lcounter > 0) {             /* release unused blocks */
                        fdblks_delta = lcounter;
                        mp->m_free[ctr].res_avail -= lcounter;
                }
                mp->m_free[ctr].res_total = request;
                if (fdblks_delta) {
                        spin_unlock(&mp->m_sb_lock);
                        xfs_add_freecounter(mp, ctr, fdblks_delta);
                        spin_lock(&mp->m_sb_lock);
                }

                goto out;
        }

        /*
         * If the request is larger than the current reservation, reserve the
         * blocks before we update the reserve counters. Sample m_free and
         * perform a partial reservation if the request exceeds free space.
         *
         * The code below estimates how many blocks it can request from
         * fdblocks to stash in the reserve pool.  This is a classic TOCTOU
         * race since fdblocks updates are not always coordinated via
         * m_sb_lock.  Set the reserve size even if there's not enough free
         * space to fill it because mod_fdblocks will refill an undersized
         * reserve when it can.
         */
        free = xfs_sum_freecounter_raw(mp, ctr) -
                xfs_freecounter_unavailable(mp, ctr);
        delta = request - mp->m_free[ctr].res_total;
        mp->m_free[ctr].res_total = request;
        if (delta > 0 && free > 0) {
                /*
                 * We'll either succeed in getting space from the free block
                 * count or we'll get an ENOSPC.  Don't set the reserved flag
                 * here - we don't want to reserve the extra reserve blocks
                 * from the reserve.
                 *
                 * The desired reserve size can change after we drop the lock.
                 * Use mod_fdblocks to put the space into the reserve or into
                 * fdblocks as appropriate.
                 */
                fdblks_delta = min(free, delta);
                spin_unlock(&mp->m_sb_lock);
                error = xfs_dec_freecounter(mp, ctr, fdblks_delta, 0);
                if (!error)
                        xfs_add_freecounter(mp, ctr, fdblks_delta);
                spin_lock(&mp->m_sb_lock);
        }
out:
        spin_unlock(&mp->m_sb_lock);
        return error;
}

int
xfs_fs_goingdown(
        xfs_mount_t     *mp,
        uint32_t        inflags)
{
        switch (inflags) {
        case XFS_FSOP_GOING_FLAGS_DEFAULT: {
                if (!bdev_freeze(mp->m_super->s_bdev)) {
                        xfs_force_shutdown(mp, SHUTDOWN_FORCE_UMOUNT);
                        bdev_thaw(mp->m_super->s_bdev);
                }
                break;
        }
        case XFS_FSOP_GOING_FLAGS_LOGFLUSH:
                xfs_force_shutdown(mp, SHUTDOWN_FORCE_UMOUNT);
                break;
        case XFS_FSOP_GOING_FLAGS_NOLOGFLUSH:
                xfs_force_shutdown(mp,
                                SHUTDOWN_FORCE_UMOUNT | SHUTDOWN_LOG_IO_ERROR);
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

/*
 * Force a shutdown of the filesystem instantly while keeping the filesystem
 * consistent. We don't do an unmount here; just shutdown the shop, make sure
 * that absolutely nothing persistent happens to this filesystem after this
 * point.
 *
 * The shutdown state change is atomic, resulting in the first and only the
 * first shutdown call processing the shutdown. This means we only shutdown the
 * log once as it requires, and we don't spam the logs when multiple concurrent
 * shutdowns race to set the shutdown flags.
 */
void
xfs_do_force_shutdown(
        struct xfs_mount *mp,
        uint32_t        flags,
        char            *fname,
        int             lnnum)
{
        int             tag;
        const char      *why;


        if (xfs_set_shutdown(mp)) {
                xlog_shutdown_wait(mp->m_log);
                return;
        }
        if (mp->m_sb_bp)
                mp->m_sb_bp->b_flags |= XBF_DONE;

        if (flags & SHUTDOWN_FORCE_UMOUNT)
                xfs_alert(mp, "User initiated shutdown received.");

        if (xlog_force_shutdown(mp->m_log, flags)) {
                tag = XFS_PTAG_SHUTDOWN_LOGERROR;
                why = "Log I/O Error";
        } else if (flags & SHUTDOWN_CORRUPT_INCORE) {
                tag = XFS_PTAG_SHUTDOWN_CORRUPT;
                why = "Corruption of in-memory data";
        } else if (flags & SHUTDOWN_CORRUPT_ONDISK) {
                tag = XFS_PTAG_SHUTDOWN_CORRUPT;
                why = "Corruption of on-disk metadata";
        } else if (flags & SHUTDOWN_DEVICE_REMOVED) {
                tag = XFS_PTAG_SHUTDOWN_IOERROR;
                why = "Block device removal";
        } else {
                tag = XFS_PTAG_SHUTDOWN_IOERROR;
                why = "Metadata I/O Error";
        }

        trace_xfs_force_shutdown(mp, tag, flags, fname, lnnum);

        xfs_alert_tag(mp, tag,
"%s (0x%x) detected at %pS (%s:%d).  Shutting down filesystem.",
                        why, flags, __return_address, fname, lnnum);
        xfs_alert(mp,
                "Please unmount the filesystem and rectify the problem(s)");
        if (xfs_error_level >= XFS_ERRLEVEL_HIGH)
                xfs_stack_trace();

        fserror_report_shutdown(mp->m_super, GFP_KERNEL);
        xfs_healthmon_report_shutdown(mp, flags);
}

/*
 * Reserve free space for per-AG metadata.
 */
int
xfs_fs_reserve_ag_blocks(
        struct xfs_mount        *mp)
{
        struct xfs_perag        *pag = NULL;
        int                     error = 0;
        int                     err2;

        mp->m_finobt_nores = false;
        while ((pag = xfs_perag_next(mp, pag))) {
                err2 = xfs_ag_resv_init(pag, NULL);
                if (err2 && !error)
                        error = err2;
        }

        if (error && error != -ENOSPC) {
                xfs_warn(mp,
        "Error %d reserving per-AG metadata reserve pool.", error);
                xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
                return error;
        }

        err2 = xfs_metafile_resv_init(mp);
        if (err2 && err2 != -ENOSPC) {
                xfs_warn(mp,
        "Error %d reserving realtime metadata reserve pool.", err2);
                xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);

                if (!error)
                        error = err2;
        }

        return error;
}

/*
 * Free space reserved for per-AG metadata.
 */
void
xfs_fs_unreserve_ag_blocks(
        struct xfs_mount        *mp)
{
        struct xfs_perag        *pag = NULL;

        xfs_metafile_resv_free(mp);
        while ((pag = xfs_perag_next(mp, pag)))
                xfs_ag_resv_free(pag);
}