// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * Copyright (c) 2016-2025 Christoph Hellwig.
 * All Rights Reserved.
 */
#include "xfs_platform.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_trans.h"
#include "xfs_iomap.h"
#include "xfs_trace.h"
#include "xfs_bmap.h"
#include "xfs_bmap_util.h"
#include "xfs_reflink.h"
#include "xfs_errortag.h"
#include "xfs_error.h"
#include "xfs_icache.h"
#include "xfs_zone_alloc.h"
#include "xfs_rtgroup.h"

struct xfs_writepage_ctx {
        struct iomap_writepage_ctx ctx;
        unsigned int            data_seq;
        unsigned int            cow_seq;
};

static inline struct xfs_writepage_ctx *
XFS_WPC(struct iomap_writepage_ctx *ctx)
{
        return container_of(ctx, struct xfs_writepage_ctx, ctx);
}

/*
 * Fast and loose check if this write could update the on-disk inode size.
 */
static inline bool xfs_ioend_is_append(struct iomap_ioend *ioend)
{
        return ioend->io_offset + ioend->io_size >
                XFS_I(ioend->io_inode)->i_disk_size;
}

/*
 * Update on-disk file size now that data has been written to disk.
 */
int
xfs_setfilesize(
        struct xfs_inode        *ip,
        xfs_off_t               offset,
        size_t                  size)
{
        struct xfs_mount        *mp = ip->i_mount;
        struct xfs_trans        *tp;
        xfs_fsize_t             isize;
        int                     error;

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

        xfs_ilock(ip, XFS_ILOCK_EXCL);
        isize = xfs_new_eof(ip, offset + size);
        if (!isize) {
                xfs_iunlock(ip, XFS_ILOCK_EXCL);
                xfs_trans_cancel(tp);
                return 0;
        }

        trace_xfs_setfilesize(ip, offset, size);

        ip->i_disk_size = isize;
        xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
        xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

        return xfs_trans_commit(tp);
}

static void
xfs_ioend_put_open_zones(
        struct iomap_ioend      *ioend)
{
        struct iomap_ioend *tmp;

        /*
         * Put the open zone for all ioends merged into this one (if any).
         */
        list_for_each_entry(tmp, &ioend->io_list, io_list)
                xfs_open_zone_put(tmp->io_private);

        /*
         * The main ioend might not have an open zone if the submission failed
         * before xfs_zone_alloc_and_submit got called.
         */
        if (ioend->io_private)
                xfs_open_zone_put(ioend->io_private);
}

/*
 * IO write completion.
 */
STATIC void
xfs_end_ioend_write(
        struct iomap_ioend      *ioend)
{
        struct xfs_inode        *ip = XFS_I(ioend->io_inode);
        struct xfs_mount        *mp = ip->i_mount;
        bool                    is_zoned = xfs_is_zoned_inode(ip);
        xfs_off_t               offset = ioend->io_offset;
        size_t                  size = ioend->io_size;
        unsigned int            nofs_flag;
        int                     error;

        /*
         * We can allocate memory here while doing writeback on behalf of
         * memory reclaim.  To avoid memory allocation deadlocks set the
         * task-wide nofs context for the following operations.
         */
        nofs_flag = memalloc_nofs_save();

        /*
         * Just clean up the in-memory structures if the fs has been shut down.
         */
        if (xfs_is_shutdown(mp)) {
                error = -EIO;
                goto done;
        }

        /*
         * Clean up all COW blocks and underlying data fork delalloc blocks on
         * I/O error. The delalloc punch is required because this ioend was
         * mapped to blocks in the COW fork and the associated pages are no
         * longer dirty. If we don't remove delalloc blocks here, they become
         * stale and can corrupt free space accounting on unmount.
         */
        error = blk_status_to_errno(ioend->io_bio.bi_status);
        if (unlikely(error)) {
                if (ioend->io_flags & IOMAP_IOEND_SHARED) {
                        ASSERT(!is_zoned);
                        xfs_reflink_cancel_cow_range(ip, offset, size, true);
                        xfs_bmap_punch_delalloc_range(ip, XFS_DATA_FORK, offset,
                                        offset + size, NULL);
                }
                goto done;
        }

        /*
         * Success: commit the COW or unwritten blocks if needed.
         */
        if (is_zoned)
                error = xfs_zoned_end_io(ip, offset, size, ioend->io_sector,
                                ioend->io_private, NULLFSBLOCK);
        else if (ioend->io_flags & IOMAP_IOEND_SHARED)
                error = xfs_reflink_end_cow(ip, offset, size);
        else if (ioend->io_flags & IOMAP_IOEND_UNWRITTEN)
                error = xfs_iomap_write_unwritten(ip, offset, size, false);

        if (!error &&
            !(ioend->io_flags & IOMAP_IOEND_DIRECT) &&
            xfs_ioend_is_append(ioend))
                error = xfs_setfilesize(ip, offset, size);
done:
        if (is_zoned)
                xfs_ioend_put_open_zones(ioend);
        iomap_finish_ioends(ioend, error);
        memalloc_nofs_restore(nofs_flag);
}

/*
 * Finish all pending IO completions that require transactional modifications.
 *
 * We try to merge physical and logically contiguous ioends before completion to
 * minimise the number of transactions we need to perform during IO completion.
 * Both unwritten extent conversion and COW remapping need to iterate and modify
 * one physical extent at a time, so we gain nothing by merging physically
 * discontiguous extents here.
 *
 * The ioend chain length that we can be processing here is largely unbound in
 * length and we may have to perform significant amounts of work on each ioend
 * to complete it. Hence we have to be careful about holding the CPU for too
 * long in this loop.
 */
void
xfs_end_io(
        struct work_struct      *work)
{
        struct xfs_inode        *ip =
                container_of(work, struct xfs_inode, i_ioend_work);
        struct iomap_ioend      *ioend;
        struct list_head        tmp;
        unsigned long           flags;

        spin_lock_irqsave(&ip->i_ioend_lock, flags);
        list_replace_init(&ip->i_ioend_list, &tmp);
        spin_unlock_irqrestore(&ip->i_ioend_lock, flags);

        iomap_sort_ioends(&tmp);
        while ((ioend = list_first_entry_or_null(&tmp, struct iomap_ioend,
                        io_list))) {
                list_del_init(&ioend->io_list);
                iomap_ioend_try_merge(ioend, &tmp);
                if (bio_op(&ioend->io_bio) == REQ_OP_READ)
                        iomap_finish_ioends(ioend,
                                blk_status_to_errno(ioend->io_bio.bi_status));
                else
                        xfs_end_ioend_write(ioend);
                cond_resched();
        }
}

void
xfs_end_bio(
        struct bio              *bio)
{
        struct iomap_ioend      *ioend = iomap_ioend_from_bio(bio);
        struct xfs_inode        *ip = XFS_I(ioend->io_inode);
        struct xfs_mount        *mp = ip->i_mount;
        unsigned long           flags;

        /*
         * For Appends record the actually written block number and set the
         * boundary flag if needed.
         */
        if (IS_ENABLED(CONFIG_XFS_RT) && bio_is_zone_append(bio)) {
                ioend->io_sector = bio->bi_iter.bi_sector;
                xfs_mark_rtg_boundary(ioend);
        }

        spin_lock_irqsave(&ip->i_ioend_lock, flags);
        if (list_empty(&ip->i_ioend_list))
                WARN_ON_ONCE(!queue_work(mp->m_unwritten_workqueue,
                                         &ip->i_ioend_work));
        list_add_tail(&ioend->io_list, &ip->i_ioend_list);
        spin_unlock_irqrestore(&ip->i_ioend_lock, flags);
}

/*
 * We cannot cancel the ioend directly on error.  We may have already set other
 * pages under writeback and hence we have to run I/O completion to mark the
 * error state of the pages under writeback appropriately.
 *
 * If the folio has delalloc blocks on it, the caller is asking us to punch them
 * out. If we don't, we can leave a stale delalloc mapping covered by a clean
 * page that needs to be dirtied again before the delalloc mapping can be
 * converted. This stale delalloc mapping can trip up a later direct I/O read
 * operation on the same region.
 *
 * We prevent this by truncating away the delalloc regions on the folio. Because
 * they are delalloc, we can do this without needing a transaction. Indeed - if
 * we get ENOSPC errors, we have to be able to do this truncation without a
 * transaction as there is no space left for block reservation (typically why
 * we see a ENOSPC in writeback).
 */
static void
xfs_discard_folio(
        struct folio            *folio,
        loff_t                  pos)
{
        struct xfs_inode        *ip = XFS_I(folio->mapping->host);
        struct xfs_mount        *mp = ip->i_mount;

        if (xfs_is_shutdown(mp))
                return;

        xfs_alert_ratelimited(mp,
                "page discard on page "PTR_FMT", inode 0x%llx, pos %llu.",
                        folio, ip->i_ino, pos);

        /*
         * The end of the punch range is always the offset of the first
         * byte of the next folio. Hence the end offset is only dependent on the
         * folio itself and not the start offset that is passed in.
         */
        xfs_bmap_punch_delalloc_range(ip, XFS_DATA_FORK, pos,
                                folio_next_pos(folio), NULL);
}

/*
 * Fast revalidation of the cached writeback mapping. Return true if the current
 * mapping is valid, false otherwise.
 */
static bool
xfs_imap_valid(
        struct iomap_writepage_ctx      *wpc,
        struct xfs_inode                *ip,
        loff_t                          offset)
{
        if (offset < wpc->iomap.offset ||
            offset >= wpc->iomap.offset + wpc->iomap.length)
                return false;
        /*
         * If this is a COW mapping, it is sufficient to check that the mapping
         * covers the offset. Be careful to check this first because the caller
         * can revalidate a COW mapping without updating the data seqno.
         */
        if (wpc->iomap.flags & IOMAP_F_SHARED)
                return true;

        /*
         * This is not a COW mapping. Check the sequence number of the data fork
         * because concurrent changes could have invalidated the extent. Check
         * the COW fork because concurrent changes since the last time we
         * checked (and found nothing at this offset) could have added
         * overlapping blocks.
         */
        if (XFS_WPC(wpc)->data_seq != READ_ONCE(ip->i_df.if_seq)) {
                trace_xfs_wb_data_iomap_invalid(ip, &wpc->iomap,
                                XFS_WPC(wpc)->data_seq, XFS_DATA_FORK);
                return false;
        }
        if (xfs_inode_has_cow_data(ip) &&
            XFS_WPC(wpc)->cow_seq != READ_ONCE(ip->i_cowfp->if_seq)) {
                trace_xfs_wb_cow_iomap_invalid(ip, &wpc->iomap,
                                XFS_WPC(wpc)->cow_seq, XFS_COW_FORK);
                return false;
        }
        return true;
}

static int
xfs_map_blocks(
        struct iomap_writepage_ctx *wpc,
        loff_t                  offset,
        unsigned int            len)
{
        struct xfs_inode        *ip = XFS_I(wpc->inode);
        struct xfs_mount        *mp = ip->i_mount;
        ssize_t                 count = i_blocksize(wpc->inode);
        xfs_fileoff_t           offset_fsb = XFS_B_TO_FSBT(mp, offset);
        xfs_fileoff_t           end_fsb = XFS_B_TO_FSB(mp, offset + count);
        xfs_fileoff_t           cow_fsb;
        int                     whichfork;
        struct xfs_bmbt_irec    imap;
        struct xfs_iext_cursor  icur;
        int                     retries = 0;
        int                     error = 0;
        unsigned int            *seq;

        if (xfs_is_shutdown(mp))
                return -EIO;

        XFS_ERRORTAG_DELAY(mp, XFS_ERRTAG_WB_DELAY_MS);

        /*
         * COW fork blocks can overlap data fork blocks even if the blocks
         * aren't shared.  COW I/O always takes precedent, so we must always
         * check for overlap on reflink inodes unless the mapping is already a
         * COW one, or the COW fork hasn't changed from the last time we looked
         * at it.
         *
         * It's safe to check the COW fork if_seq here without the ILOCK because
         * we've indirectly protected against concurrent updates: writeback has
         * the page locked, which prevents concurrent invalidations by reflink
         * and directio and prevents concurrent buffered writes to the same
         * page.  Changes to if_seq always happen under i_lock, which protects
         * against concurrent updates and provides a memory barrier on the way
         * out that ensures that we always see the current value.
         */
        if (xfs_imap_valid(wpc, ip, offset))
                return 0;

        /*
         * If we don't have a valid map, now it's time to get a new one for this
         * offset.  This will convert delayed allocations (including COW ones)
         * into real extents.  If we return without a valid map, it means we
         * landed in a hole and we skip the block.
         */
retry:
        cow_fsb = NULLFILEOFF;
        whichfork = XFS_DATA_FORK;
        xfs_ilock(ip, XFS_ILOCK_SHARED);
        ASSERT(!xfs_need_iread_extents(&ip->i_df));

        /*
         * Check if this is offset is covered by a COW extents, and if yes use
         * it directly instead of looking up anything in the data fork.
         */
        if (xfs_inode_has_cow_data(ip) &&
            xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &imap))
                cow_fsb = imap.br_startoff;
        if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
                XFS_WPC(wpc)->cow_seq = READ_ONCE(ip->i_cowfp->if_seq);
                xfs_iunlock(ip, XFS_ILOCK_SHARED);

                whichfork = XFS_COW_FORK;
                goto allocate_blocks;
        }

        /*
         * No COW extent overlap. Revalidate now that we may have updated
         * ->cow_seq. If the data mapping is still valid, we're done.
         */
        if (xfs_imap_valid(wpc, ip, offset)) {
                xfs_iunlock(ip, XFS_ILOCK_SHARED);
                return 0;
        }

        /*
         * If we don't have a valid map, now it's time to get a new one for this
         * offset.  This will convert delayed allocations (including COW ones)
         * into real extents.
         */
        if (!xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap))
                imap.br_startoff = end_fsb;     /* fake a hole past EOF */
        XFS_WPC(wpc)->data_seq = READ_ONCE(ip->i_df.if_seq);
        xfs_iunlock(ip, XFS_ILOCK_SHARED);

        /* landed in a hole or beyond EOF? */
        if (imap.br_startoff > offset_fsb) {
                imap.br_blockcount = imap.br_startoff - offset_fsb;
                imap.br_startoff = offset_fsb;
                imap.br_startblock = HOLESTARTBLOCK;
                imap.br_state = XFS_EXT_NORM;
        }

        /*
         * Truncate to the next COW extent if there is one.  This is the only
         * opportunity to do this because we can skip COW fork lookups for the
         * subsequent blocks in the mapping; however, the requirement to treat
         * the COW range separately remains.
         */
        if (cow_fsb != NULLFILEOFF &&
            cow_fsb < imap.br_startoff + imap.br_blockcount)
                imap.br_blockcount = cow_fsb - imap.br_startoff;

        /* got a delalloc extent? */
        if (imap.br_startblock != HOLESTARTBLOCK &&
            isnullstartblock(imap.br_startblock))
                goto allocate_blocks;

        xfs_bmbt_to_iomap(ip, &wpc->iomap, &imap, 0, 0, XFS_WPC(wpc)->data_seq);
        trace_xfs_map_blocks_found(ip, offset, count, whichfork, &imap);
        return 0;
allocate_blocks:
        /*
         * Convert a dellalloc extent to a real one. The current page is held
         * locked so nothing could have removed the block backing offset_fsb,
         * although it could have moved from the COW to the data fork by another
         * thread.
         */
        if (whichfork == XFS_COW_FORK)
                seq = &XFS_WPC(wpc)->cow_seq;
        else
                seq = &XFS_WPC(wpc)->data_seq;

        error = xfs_bmapi_convert_delalloc(ip, whichfork, offset,
                                &wpc->iomap, seq);
        if (error) {
                /*
                 * If we failed to find the extent in the COW fork we might have
                 * raced with a COW to data fork conversion or truncate.
                 * Restart the lookup to catch the extent in the data fork for
                 * the former case, but prevent additional retries to avoid
                 * looping forever for the latter case.
                 */
                if (error == -EAGAIN && whichfork == XFS_COW_FORK && !retries++)
                        goto retry;
                ASSERT(error != -EAGAIN);
                return error;
        }

        /*
         * Due to merging the return real extent might be larger than the
         * original delalloc one.  Trim the return extent to the next COW
         * boundary again to force a re-lookup.
         */
        if (whichfork != XFS_COW_FORK && cow_fsb != NULLFILEOFF) {
                loff_t          cow_offset = XFS_FSB_TO_B(mp, cow_fsb);

                if (cow_offset < wpc->iomap.offset + wpc->iomap.length)
                        wpc->iomap.length = cow_offset - wpc->iomap.offset;
        }

        ASSERT(wpc->iomap.offset <= offset);
        ASSERT(wpc->iomap.offset + wpc->iomap.length > offset);
        trace_xfs_map_blocks_alloc(ip, offset, count, whichfork, &imap);
        return 0;
}

static ssize_t
xfs_writeback_range(
        struct iomap_writepage_ctx *wpc,
        struct folio            *folio,
        u64                     offset,
        unsigned int            len,
        u64                     end_pos)
{
        ssize_t                 ret;

        ret = xfs_map_blocks(wpc, offset, len);
        if (!ret)
                ret = iomap_add_to_ioend(wpc, folio, offset, end_pos, len);
        if (ret < 0)
                xfs_discard_folio(folio, offset);
        return ret;
}

static bool
xfs_ioend_needs_wq_completion(
        struct iomap_ioend      *ioend)
{
        /* Changing inode size requires a transaction. */
        if (xfs_ioend_is_append(ioend))
                return true;

        /* Extent manipulation requires a transaction. */
        if (ioend->io_flags & (IOMAP_IOEND_UNWRITTEN | IOMAP_IOEND_SHARED))
                return true;

        /* Page cache invalidation cannot be done in irq context. */
        if (ioend->io_flags & IOMAP_IOEND_DONTCACHE)
                return true;

        return false;
}

static int
xfs_writeback_submit(
        struct iomap_writepage_ctx      *wpc,
        int                             error)
{
        struct iomap_ioend              *ioend = wpc->wb_ctx;

        /*
         * Convert CoW extents to regular.
         *
         * We can allocate memory here while doing writeback on behalf of memory
         * reclaim.  To avoid memory allocation deadlocks, set the task-wide
         * nofs context.
         */
        if (!error && (ioend->io_flags & IOMAP_IOEND_SHARED)) {
                unsigned int            nofs_flag;

                nofs_flag = memalloc_nofs_save();
                error = xfs_reflink_convert_cow(XFS_I(ioend->io_inode),
                                ioend->io_offset, ioend->io_size);
                memalloc_nofs_restore(nofs_flag);
        }

        /*
         * Send ioends that might require a transaction to the completion wq.
         */
        if (xfs_ioend_needs_wq_completion(ioend))
                ioend->io_bio.bi_end_io = xfs_end_bio;

        return iomap_ioend_writeback_submit(wpc, error);
}

static const struct iomap_writeback_ops xfs_writeback_ops = {
        .writeback_range        = xfs_writeback_range,
        .writeback_submit       = xfs_writeback_submit,
};

struct xfs_zoned_writepage_ctx {
        struct iomap_writepage_ctx      ctx;
        struct xfs_open_zone            *open_zone;
};

static inline struct xfs_zoned_writepage_ctx *
XFS_ZWPC(struct iomap_writepage_ctx *ctx)
{
        return container_of(ctx, struct xfs_zoned_writepage_ctx, ctx);
}

static int
xfs_zoned_map_blocks(
        struct iomap_writepage_ctx *wpc,
        loff_t                  offset,
        unsigned int            len)
{
        struct xfs_inode        *ip = XFS_I(wpc->inode);
        struct xfs_mount        *mp = ip->i_mount;
        xfs_fileoff_t           offset_fsb = XFS_B_TO_FSBT(mp, offset);
        xfs_fileoff_t           end_fsb = XFS_B_TO_FSB(mp, offset + len);
        xfs_filblks_t           count_fsb;
        struct xfs_bmbt_irec    imap, del;
        struct xfs_iext_cursor  icur;

        if (xfs_is_shutdown(mp))
                return -EIO;

        XFS_ERRORTAG_DELAY(mp, XFS_ERRTAG_WB_DELAY_MS);

        /*
         * All dirty data must be covered by delalloc extents.  But truncate can
         * remove delalloc extents underneath us or reduce their size.
         * Returning a hole tells iomap to not write back any data from this
         * range, which is the right thing to do in that case.
         *
         * Otherwise just tell iomap to treat ranges previously covered by a
         * delalloc extent as mapped.  The actual block allocation will be done
         * just before submitting the bio.
         *
         * This implies we never map outside folios that are locked or marked
         * as under writeback, and thus there is no need check the fork sequence
         * count here.
         */
        xfs_ilock(ip, XFS_ILOCK_EXCL);
        if (!xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &imap))
                imap.br_startoff = end_fsb;     /* fake a hole past EOF */
        if (imap.br_startoff > offset_fsb) {
                imap.br_blockcount = imap.br_startoff - offset_fsb;
                imap.br_startoff = offset_fsb;
                imap.br_startblock = HOLESTARTBLOCK;
                imap.br_state = XFS_EXT_NORM;
                xfs_iunlock(ip, XFS_ILOCK_EXCL);
                xfs_bmbt_to_iomap(ip, &wpc->iomap, &imap, 0, 0, 0);
                return 0;
        }
        end_fsb = min(end_fsb, imap.br_startoff + imap.br_blockcount);
        count_fsb = end_fsb - offset_fsb;

        del = imap;
        xfs_trim_extent(&del, offset_fsb, count_fsb);
        xfs_bmap_del_extent_delay(ip, XFS_COW_FORK, &icur, &imap, &del,
                        XFS_BMAPI_REMAP);
        xfs_iunlock(ip, XFS_ILOCK_EXCL);

        wpc->iomap.type = IOMAP_MAPPED;
        wpc->iomap.flags = IOMAP_F_DIRTY;
        wpc->iomap.bdev = mp->m_rtdev_targp->bt_bdev;
        wpc->iomap.offset = offset;
        wpc->iomap.length = XFS_FSB_TO_B(mp, count_fsb);
        wpc->iomap.flags = IOMAP_F_ANON_WRITE;

        trace_xfs_zoned_map_blocks(ip, offset, wpc->iomap.length);
        return 0;
}

static ssize_t
xfs_zoned_writeback_range(
        struct iomap_writepage_ctx *wpc,
        struct folio            *folio,
        u64                     offset,
        unsigned int            len,
        u64                     end_pos)
{
        ssize_t                 ret;

        ret = xfs_zoned_map_blocks(wpc, offset, len);
        if (!ret)
                ret = iomap_add_to_ioend(wpc, folio, offset, end_pos, len);
        if (ret < 0)
                xfs_discard_folio(folio, offset);
        return ret;
}

static int
xfs_zoned_writeback_submit(
        struct iomap_writepage_ctx      *wpc,
        int                             error)
{
        struct iomap_ioend              *ioend = wpc->wb_ctx;

        ioend->io_bio.bi_end_io = xfs_end_bio;
        if (error) {
                ioend->io_bio.bi_status = errno_to_blk_status(error);
                bio_endio(&ioend->io_bio);
                return error;
        }
        xfs_zone_alloc_and_submit(ioend, &XFS_ZWPC(wpc)->open_zone);
        return 0;
}

static const struct iomap_writeback_ops xfs_zoned_writeback_ops = {
        .writeback_range        = xfs_zoned_writeback_range,
        .writeback_submit       = xfs_zoned_writeback_submit,
};

STATIC int
xfs_vm_writepages(
        struct address_space    *mapping,
        struct writeback_control *wbc)
{
        struct xfs_inode        *ip = XFS_I(mapping->host);

        xfs_iflags_clear(ip, XFS_ITRUNCATED);

        if (xfs_is_zoned_inode(ip)) {
                struct xfs_zoned_writepage_ctx  xc = {
                        .ctx = {
                                .inode  = mapping->host,
                                .wbc    = wbc,
                                .ops    = &xfs_zoned_writeback_ops
                        },
                };
                int                             error;

                error = iomap_writepages(&xc.ctx);
                if (xc.open_zone)
                        xfs_open_zone_put(xc.open_zone);
                return error;
        } else {
                struct xfs_writepage_ctx        wpc = {
                        .ctx = {
                                .inode  = mapping->host,
                                .wbc    = wbc,
                                .ops    = &xfs_writeback_ops
                        },
                };

                return iomap_writepages(&wpc.ctx);
        }
}

STATIC int
xfs_dax_writepages(
        struct address_space    *mapping,
        struct writeback_control *wbc)
{
        struct xfs_inode        *ip = XFS_I(mapping->host);

        xfs_iflags_clear(ip, XFS_ITRUNCATED);
        return dax_writeback_mapping_range(mapping,
                        xfs_inode_buftarg(ip)->bt_daxdev, wbc);
}

STATIC sector_t
xfs_vm_bmap(
        struct address_space    *mapping,
        sector_t                block)
{
        struct xfs_inode        *ip = XFS_I(mapping->host);

        trace_xfs_vm_bmap(ip);

        /*
         * The swap code (ab-)uses ->bmap to get a block mapping and then
         * bypasses the file system for actual I/O.  We really can't allow
         * that on reflinks inodes, so we have to skip out here.  And yes,
         * 0 is the magic code for a bmap error.
         *
         * Since we don't pass back blockdev info, we can't return bmap
         * information for rt files either.
         */
        if (xfs_is_cow_inode(ip) || XFS_IS_REALTIME_INODE(ip))
                return 0;
        return iomap_bmap(mapping, block, &xfs_read_iomap_ops);
}

STATIC int
xfs_vm_read_folio(
        struct file             *unused,
        struct folio            *folio)
{
        iomap_bio_read_folio(folio, &xfs_read_iomap_ops);
        return 0;
}

STATIC void
xfs_vm_readahead(
        struct readahead_control        *rac)
{
        iomap_bio_readahead(rac, &xfs_read_iomap_ops);
}

static int
xfs_vm_swap_activate(
        struct swap_info_struct         *sis,
        struct file                     *swap_file,
        sector_t                        *span)
{
        struct xfs_inode                *ip = XFS_I(file_inode(swap_file));

        if (xfs_is_zoned_inode(ip))
                return -EINVAL;

        /*
         * Swap file activation can race against concurrent shared extent
         * removal in files that have been cloned.  If this happens,
         * iomap_swapfile_iter() can fail because it encountered a shared
         * extent even though an operation is in progress to remove those
         * shared extents.
         *
         * This race becomes problematic when we defer extent removal
         * operations beyond the end of a syscall (i.e. use async background
         * processing algorithms).  Users think the extents are no longer
         * shared, but iomap_swapfile_iter() still sees them as shared
         * because the refcountbt entries for the extents being removed have
         * not yet been updated.  Hence the swapon call fails unexpectedly.
         *
         * The race condition is currently most obvious from the unlink()
         * operation as extent removal is deferred until after the last
         * reference to the inode goes away.  We then process the extent
         * removal asynchronously, hence triggers the "syscall completed but
         * work not done" condition mentioned above.  To close this race
         * window, we need to flush any pending inodegc operations to ensure
         * they have updated the refcountbt records before we try to map the
         * swapfile.
         */
        xfs_inodegc_flush(ip->i_mount);

        /*
         * Direct the swap code to the correct block device when this file
         * sits on the RT device.
         */
        sis->bdev = xfs_inode_buftarg(ip)->bt_bdev;

        return iomap_swapfile_activate(sis, swap_file, span,
                        &xfs_read_iomap_ops);
}

const struct address_space_operations xfs_address_space_operations = {
        .read_folio             = xfs_vm_read_folio,
        .readahead              = xfs_vm_readahead,
        .writepages             = xfs_vm_writepages,
        .dirty_folio            = iomap_dirty_folio,
        .release_folio          = iomap_release_folio,
        .invalidate_folio       = iomap_invalidate_folio,
        .bmap                   = xfs_vm_bmap,
        .migrate_folio          = filemap_migrate_folio,
        .is_partially_uptodate  = iomap_is_partially_uptodate,
        .error_remove_folio     = generic_error_remove_folio,
        .swap_activate          = xfs_vm_swap_activate,
};

const struct address_space_operations xfs_dax_aops = {
        .writepages             = xfs_dax_writepages,
        .dirty_folio            = noop_dirty_folio,
        .swap_activate          = xfs_vm_swap_activate,
};