Use the new iomap writeback code that was copied from XFS to perform
writeback.

Signed-off-by: Christoph Hellwig <h...@lst.de>
[darrick: reduce this patch only to convert the xfs writeback code]
Signed-off-by: Darrick J. Wong <darrick.w...@oracle.com>
---
 fs/xfs/xfs_aops.c  | 667 +++++----------------------------------------
 fs/xfs/xfs_aops.h  |  17 --
 fs/xfs/xfs_super.c |  11 +-
 fs/xfs/xfs_trace.h |  39 ---
 4 files changed, 74 insertions(+), 660 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 8c101081e3b1..d0a25b822123 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -18,16 +18,18 @@
 #include "xfs_bmap_util.h"
 #include "xfs_reflink.h"
 
-/*
- * structure owned by writepages passed to individual writepage calls
- */
 struct xfs_writepage_ctx {
-       struct iomap            iomap;
+       struct iomap_writepage_ctx ctx;
        unsigned int            data_seq;
        unsigned int            cow_seq;
-       struct xfs_ioend        *ioend;
 };
 
+static inline struct xfs_writepage_ctx *
+XFS_WPC(struct iomap_writepage_ctx *ctx)
+{
+       return container_of(ctx, struct xfs_writepage_ctx, ctx);
+}
+
 struct block_device *
 xfs_find_bdev_for_inode(
        struct inode            *inode)
@@ -54,71 +56,10 @@ xfs_find_daxdev_for_inode(
                return mp->m_ddev_targp->bt_daxdev;
 }
 
-static void
-xfs_finish_page_writeback(
-       struct inode            *inode,
-       struct bio_vec  *bvec,
-       int                     error)
-{
-       struct iomap_page       *iop = to_iomap_page(bvec->bv_page);
-
-       if (error) {
-               SetPageError(bvec->bv_page);
-               mapping_set_error(inode->i_mapping, -EIO);
-       }
-
-       ASSERT(iop || i_blocksize(inode) == PAGE_SIZE);
-       ASSERT(!iop || atomic_read(&iop->write_count) > 0);
-
-       if (!iop || atomic_dec_and_test(&iop->write_count))
-               end_page_writeback(bvec->bv_page);
-}
-
-/*
- * We're now finished for good with this ioend structure.  Update the page
- * state, release holds on bios, and finally free up memory.  Do not use the
- * ioend after this.
- */
-STATIC void
-xfs_destroy_ioend(
-       struct xfs_ioend        *ioend,
-       int                     error)
-{
-       struct inode            *inode = ioend->io_inode;
-       struct bio              *bio = &ioend->io_inline_bio;
-       struct bio              *last = ioend->io_bio, *next;
-       u64                     start = bio->bi_iter.bi_sector;
-       bool                    quiet = bio_flagged(bio, BIO_QUIET);
-
-       for (bio = &ioend->io_inline_bio; bio; bio = next) {
-               struct bio_vec  *bvec;
-               struct bvec_iter_all iter_all;
-
-               /*
-                * For the last bio, bi_private points to the ioend, so we
-                * need to explicitly end the iteration here.
-                */
-               if (bio == last)
-                       next = NULL;
-               else
-                       next = bio->bi_private;
-
-               /* walk each page on bio, ending page IO on them */
-               bio_for_each_segment_all(bvec, bio, iter_all)
-                       xfs_finish_page_writeback(inode, bvec, error);
-               bio_put(bio);
-       }
-
-       if (unlikely(error && !quiet)) {
-               xfs_err_ratelimited(XFS_I(inode)->i_mount,
-                       "writeback error on sector %llu", start);
-       }
-}
-
 /*
  * Fast and loose check if this write could update the on-disk inode size.
  */
-static inline bool xfs_ioend_is_append(struct xfs_ioend *ioend)
+static inline bool xfs_ioend_is_append(struct iomap_ioend *ioend)
 {
        return ioend->io_offset + ioend->io_size >
                XFS_I(ioend->io_inode)->i_d.di_size;
@@ -126,7 +67,7 @@ static inline bool xfs_ioend_is_append(struct xfs_ioend 
*ioend)
 
 STATIC int
 xfs_setfilesize_trans_alloc(
-       struct xfs_ioend        *ioend)
+       struct iomap_ioend      *ioend)
 {
        struct xfs_mount        *mp = XFS_I(ioend->io_inode)->i_mount;
        struct xfs_trans        *tp;
@@ -136,7 +77,7 @@ xfs_setfilesize_trans_alloc(
        if (error)
                return error;
 
-       ioend->io_append_trans = tp;
+       ioend->io_private = tp;
 
        /*
         * We may pass freeze protection with a transaction.  So tell lockdep
@@ -199,11 +140,11 @@ xfs_setfilesize(
 
 STATIC int
 xfs_setfilesize_ioend(
-       struct xfs_ioend        *ioend,
+       struct iomap_ioend      *ioend,
        int                     error)
 {
        struct xfs_inode        *ip = XFS_I(ioend->io_inode);
-       struct xfs_trans        *tp = ioend->io_append_trans;
+       struct xfs_trans        *tp = ioend->io_private;
 
        /*
         * The transaction may have been allocated in the I/O submission thread,
@@ -227,9 +168,8 @@ xfs_setfilesize_ioend(
  */
 STATIC void
 xfs_end_ioend(
-       struct xfs_ioend        *ioend)
+       struct iomap_ioend      *ioend)
 {
-       struct list_head        ioend_list;
        struct xfs_inode        *ip = XFS_I(ioend->io_inode);
        xfs_off_t               offset = ioend->io_offset;
        size_t                  size = ioend->io_size;
@@ -269,45 +209,15 @@ xfs_end_ioend(
        else if (ioend->io_type == IOMAP_UNWRITTEN)
                error = xfs_iomap_write_unwritten(ip, offset, size, false);
        else
-               ASSERT(!xfs_ioend_is_append(ioend) || ioend->io_append_trans);
+               ASSERT(!xfs_ioend_is_append(ioend) || ioend->io_private);
 
 done:
-       if (ioend->io_append_trans)
+       if (ioend->io_private)
                error = xfs_setfilesize_ioend(ioend, error);
-       list_replace_init(&ioend->io_list, &ioend_list);
-       xfs_destroy_ioend(ioend, error);
-
-       while (!list_empty(&ioend_list)) {
-               ioend = list_first_entry(&ioend_list, struct xfs_ioend,
-                               io_list);
-               list_del_init(&ioend->io_list);
-               xfs_destroy_ioend(ioend, error);
-       }
-
+       iomap_finish_ioends(ioend, error);
        memalloc_nofs_restore(nofs_flag);
 }
 
-/*
- * We can merge two adjacent ioends if they have the same set of work to do.
- */
-static bool
-xfs_ioend_can_merge(
-       struct xfs_ioend        *ioend,
-       struct xfs_ioend        *next)
-{
-       if (ioend->io_bio->bi_status != next->io_bio->bi_status)
-               return false;
-       if ((ioend->io_flags & IOMAP_F_SHARED) ^
-           (next->io_flags & IOMAP_F_SHARED))
-               return false;
-       if ((ioend->io_type == IOMAP_UNWRITTEN) ^
-           (next->io_type == IOMAP_UNWRITTEN))
-               return false;
-       if (ioend->io_offset + ioend->io_size != next->io_offset)
-               return false;
-       return true;
-}
-
 /*
  * If the to be merged ioend has a preallocated transaction for file
  * size updates we need to ensure the ioend it is merged into also
@@ -315,80 +225,38 @@ xfs_ioend_can_merge(
  * as it is guaranteed to be clean.
  */
 static void
-xfs_ioend_merge_append_transactions(
-       struct xfs_ioend        *ioend,
-       struct xfs_ioend        *next)
+xfs_ioend_merge_private(
+       struct iomap_ioend      *ioend,
+       struct iomap_ioend      *next)
 {
-       if (!ioend->io_append_trans) {
-               ioend->io_append_trans = next->io_append_trans;
-               next->io_append_trans = NULL;
+       if (!ioend->io_private) {
+               ioend->io_private = next->io_private;
+               next->io_private = NULL;
        } else {
                xfs_setfilesize_ioend(next, -ECANCELED);
        }
 }
 
-/* Try to merge adjacent completions. */
-STATIC void
-xfs_ioend_try_merge(
-       struct xfs_ioend        *ioend,
-       struct list_head        *more_ioends)
-{
-       struct xfs_ioend        *next_ioend;
-
-       while (!list_empty(more_ioends)) {
-               next_ioend = list_first_entry(more_ioends, struct xfs_ioend,
-                               io_list);
-               if (!xfs_ioend_can_merge(ioend, next_ioend))
-                       break;
-               list_move_tail(&next_ioend->io_list, &ioend->io_list);
-               ioend->io_size += next_ioend->io_size;
-               if (next_ioend->io_append_trans)
-                       xfs_ioend_merge_append_transactions(ioend, next_ioend);
-       }
-}
-
-/* list_sort compare function for ioends */
-static int
-xfs_ioend_compare(
-       void                    *priv,
-       struct list_head        *a,
-       struct list_head        *b)
-{
-       struct xfs_ioend        *ia;
-       struct xfs_ioend        *ib;
-
-       ia = container_of(a, struct xfs_ioend, io_list);
-       ib = container_of(b, struct xfs_ioend, io_list);
-       if (ia->io_offset < ib->io_offset)
-               return -1;
-       else if (ia->io_offset > ib->io_offset)
-               return 1;
-       return 0;
-}
-
 /* Finish all pending io completions. */
 void
 xfs_end_io(
        struct work_struct      *work)
 {
-       struct xfs_inode        *ip;
-       struct xfs_ioend        *ioend;
-       struct list_head        completion_list;
+       struct xfs_inode        *ip =
+               container_of(work, struct xfs_inode, i_ioend_work);
+       struct iomap_ioend      *ioend;
+       struct list_head        tmp;
        unsigned long           flags;
 
-       ip = container_of(work, struct xfs_inode, i_ioend_work);
-
        spin_lock_irqsave(&ip->i_ioend_lock, flags);
-       list_replace_init(&ip->i_ioend_list, &completion_list);
+       list_replace_init(&ip->i_ioend_list, &tmp);
        spin_unlock_irqrestore(&ip->i_ioend_lock, flags);
 
-       list_sort(NULL, &completion_list, xfs_ioend_compare);
-
-       while (!list_empty(&completion_list)) {
-               ioend = list_first_entry(&completion_list, struct xfs_ioend,
-                               io_list);
+       iomap_sort_ioends(&tmp);
+       while (!list_empty(&tmp)) {
+               ioend = list_first_entry(&tmp, struct iomap_ioend, io_list);
                list_del_init(&ioend->io_list);
-               xfs_ioend_try_merge(ioend, &completion_list);
+               iomap_ioend_try_merge(ioend, &tmp, xfs_ioend_merge_private);
                xfs_end_ioend(ioend);
        }
 }
@@ -397,22 +265,16 @@ STATIC void
 xfs_end_bio(
        struct bio              *bio)
 {
-       struct xfs_ioend        *ioend = bio->bi_private;
+       struct iomap_ioend      *ioend = bio->bi_private;
        struct xfs_inode        *ip = XFS_I(ioend->io_inode);
-       struct xfs_mount        *mp = ip->i_mount;
        unsigned long           flags;
 
-       if ((ioend->io_flags & IOMAP_F_SHARED) ||
-           ioend->io_type == IOMAP_UNWRITTEN ||
-           ioend->io_append_trans != NULL) {
-               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);
-       } else
-               xfs_destroy_ioend(ioend, blk_status_to_errno(bio->bi_status));
+       spin_lock_irqsave(&ip->i_ioend_lock, flags);
+       if (list_empty(&ip->i_ioend_list))
+               WARN_ON_ONCE(!queue_work(ip->i_mount->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);
 }
 
 /*
@@ -421,7 +283,7 @@ xfs_end_bio(
  */
 static bool
 xfs_imap_valid(
-       struct xfs_writepage_ctx        *wpc,
+       struct iomap_writepage_ctx      *wpc,
        struct xfs_inode                *ip,
        loff_t                          offset)
 {
@@ -443,10 +305,10 @@ xfs_imap_valid(
         * checked (and found nothing at this offset) could have added
         * overlapping blocks.
         */
-       if (wpc->data_seq != READ_ONCE(ip->i_df.if_seq))
+       if (XFS_WPC(wpc)->data_seq != READ_ONCE(ip->i_df.if_seq))
                return false;
        if (xfs_inode_has_cow_data(ip) &&
-           wpc->cow_seq != READ_ONCE(ip->i_cowfp->if_seq))
+           XFS_WPC(wpc)->cow_seq != READ_ONCE(ip->i_cowfp->if_seq))
                return false;
        return true;
 }
@@ -461,12 +323,18 @@ xfs_imap_valid(
  */
 static int
 xfs_convert_blocks(
-       struct xfs_writepage_ctx *wpc,
+       struct iomap_writepage_ctx *wpc,
        struct xfs_inode        *ip,
        int                     whichfork,
        loff_t                  offset)
 {
        int                     error;
+       unsigned                *seq;
+
+       if (whichfork == XFS_COW_FORK)
+               seq = &XFS_WPC(wpc)->cow_seq;
+       else
+               seq = &XFS_WPC(wpc)->data_seq;
 
        /*
         * Attempt to allocate whatever delalloc extent currently backs offset
@@ -476,8 +344,7 @@ xfs_convert_blocks(
         */
        do {
                error = xfs_bmapi_convert_delalloc(ip, whichfork, offset,
-                               &wpc->iomap, whichfork == XFS_COW_FORK ?
-                                       &wpc->cow_seq : &wpc->data_seq);
+                               &wpc->iomap, seq);
                if (error)
                        return error;
        } while (wpc->iomap.offset + wpc->iomap.length <= offset);
@@ -485,9 +352,9 @@ xfs_convert_blocks(
        return 0;
 }
 
-STATIC int
+static int
 xfs_map_blocks(
-       struct xfs_writepage_ctx *wpc,
+       struct iomap_writepage_ctx *wpc,
        struct inode            *inode,
        loff_t                  offset)
 {
@@ -543,7 +410,7 @@ xfs_map_blocks(
            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) {
-               wpc->cow_seq = READ_ONCE(ip->i_cowfp->if_seq);
+               XFS_WPC(wpc)->cow_seq = READ_ONCE(ip->i_cowfp->if_seq);
                xfs_iunlock(ip, XFS_ILOCK_SHARED);
 
                whichfork = XFS_COW_FORK;
@@ -566,7 +433,7 @@ xfs_map_blocks(
         */
        if (!xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap))
                imap.br_startoff = end_fsb;     /* fake a hole past EOF */
-       wpc->data_seq = READ_ONCE(ip->i_df.if_seq);
+       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? */
@@ -630,24 +497,9 @@ xfs_map_blocks(
        return 0;
 }
 
-/*
- * Submit the bio for an ioend. We are passed an ioend with a bio attached to
- * it, and we submit that bio. The ioend may be used for multiple bio
- * submissions, so we only want to allocate an append transaction for the ioend
- * once. In the case of multiple bio submission, each bio will take an IO
- * reference to the ioend to ensure that the ioend completion is only done once
- * all bios have been submitted and the ioend is really done.
- *
- * If @status is non-zero, it means that we have a situation where some part of
- * the submission process has failed after we have marked paged for writeback
- * and unlocked them. In this situation, we need to fail the bio and ioend
- * rather than submit it to IO. This typically only happens on a filesystem
- * shutdown.
- */
-STATIC int
+static int
 xfs_submit_ioend(
-       struct writeback_control *wbc,
-       struct xfs_ioend        *ioend,
+       struct iomap_ioend      *ioend,
        int                     status)
 {
        unsigned int            nofs_flag;
@@ -670,139 +522,15 @@ xfs_submit_ioend(
            ((ioend->io_flags & IOMAP_F_SHARED) ||
             ioend->io_type != IOMAP_UNWRITTEN) &&
            xfs_ioend_is_append(ioend) &&
-           !ioend->io_append_trans)
+           !ioend->io_private)
                status = xfs_setfilesize_trans_alloc(ioend);
 
        memalloc_nofs_restore(nofs_flag);
-
-       ioend->io_bio->bi_private = ioend;
-       ioend->io_bio->bi_end_io = xfs_end_bio;
-
-       /*
-        * If we are failing the IO now, just mark the ioend with an
-        * error and finish it. This will run IO completion immediately
-        * as there is only one reference to the ioend at this point in
-        * time.
-        */
-       if (status) {
-               ioend->io_bio->bi_status = errno_to_blk_status(status);
-               bio_endio(ioend->io_bio);
-               return status;
-       }
-
-       submit_bio(ioend->io_bio);
-       return 0;
-}
-
-static struct xfs_ioend *
-xfs_alloc_ioend(
-       struct inode            *inode,
-       struct xfs_writepage_ctx *wpc,
-       xfs_off_t               offset,
-       sector_t                sector,
-       struct writeback_control *wbc)
-{
-       struct xfs_ioend        *ioend;
-       struct bio              *bio;
-
-       bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, &xfs_ioend_bioset);
-       bio_set_dev(bio, wpc->iomap.bdev);
-       bio->bi_iter.bi_sector = sector;
-       bio->bi_opf = REQ_OP_WRITE | wbc_to_write_flags(wbc);
-       bio->bi_write_hint = inode->i_write_hint;
-       wbc_init_bio(wbc, bio);
-
-       ioend = container_of(bio, struct xfs_ioend, io_inline_bio);
-       INIT_LIST_HEAD(&ioend->io_list);
-       ioend->io_type = wpc->iomap.type;
-       ioend->io_flags = wpc->iomap.flags;
-       ioend->io_inode = inode;
-       ioend->io_size = 0;
-       ioend->io_offset = offset;
-       ioend->io_append_trans = NULL;
-       ioend->io_bio = bio;
-       return ioend;
-}
-
-/*
- * Allocate a new bio, and chain the old bio to the new one.
- *
- * Note that we have to do perform the chaining in this unintuitive order
- * so that the bi_private linkage is set up in the right direction for the
- * traversal in xfs_destroy_ioend().
- */
-static struct bio *
-xfs_chain_bio(
-       struct bio              *prev)
-{
-       struct bio *new;
-
-       new = bio_alloc(GFP_NOFS, BIO_MAX_PAGES);
-       bio_copy_dev(new, prev);/* also copies over blkcg information */
-       new->bi_iter.bi_sector = bio_end_sector(prev);
-       new->bi_opf = prev->bi_opf;
-       new->bi_write_hint = prev->bi_write_hint;
-
-       bio_chain(prev, new);
-       bio_get(prev);          /* for xfs_destroy_ioend */
-       submit_bio(prev);
-       return new;
-}
-
-/*
- * Test to see if we have an existing ioend structure that we could append to
- * first, otherwise finish off the current ioend and start another.
- */
-STATIC void
-xfs_add_to_ioend(
-       struct inode            *inode,
-       xfs_off_t               offset,
-       struct page             *page,
-       struct iomap_page       *iop,
-       struct xfs_writepage_ctx *wpc,
-       struct writeback_control *wbc,
-       struct list_head        *iolist)
-{
-       sector_t                sector = iomap_sector(&wpc->iomap, offset);
-       unsigned                len = i_blocksize(inode);
-       unsigned                poff = offset & (PAGE_SIZE - 1);
-       bool                    merged, same_page = false;
-
-       if (!wpc->ioend ||
-           (wpc->iomap.flags & IOMAP_F_SHARED) !=
-           (wpc->ioend->io_flags & IOMAP_F_SHARED) ||
-           wpc->iomap.type != wpc->ioend->io_type ||
-           sector != bio_end_sector(wpc->ioend->io_bio) ||
-           offset != wpc->ioend->io_offset + wpc->ioend->io_size) {
-               if (wpc->ioend)
-                       list_add(&wpc->ioend->io_list, iolist);
-               wpc->ioend = xfs_alloc_ioend(inode, wpc, offset, sector, wbc);
-       }
-
-       merged = __bio_try_merge_page(wpc->ioend->io_bio, page, len, poff,
-                       &same_page);
-
-       if (iop && !same_page)
-               atomic_inc(&iop->write_count);
-
-       if (!merged) {
-               if (bio_full(wpc->ioend->io_bio, len))
-                       wpc->ioend->io_bio = xfs_chain_bio(wpc->ioend->io_bio);
-               bio_add_page(wpc->ioend->io_bio, page, len, poff);
-       }
-
-       wpc->ioend->io_size += len;
-       wbc_account_cgroup_owner(wbc, page, len);
-}
-
-STATIC void
-xfs_vm_invalidatepage(
-       struct page             *page,
-       unsigned int            offset,
-       unsigned int            length)
-{
-       trace_xfs_invalidatepage(page->mapping->host, page, offset, length);
-       iomap_invalidatepage(page, offset, length);
+       if ((ioend->io_flags & IOMAP_F_SHARED) ||
+           ioend->io_type == IOMAP_UNWRITTEN ||
+           ioend->io_private)
+               ioend->io_bio->bi_end_io = xfs_end_bio;
+       return status;
 }
 
 /*
@@ -816,8 +544,8 @@ xfs_vm_invalidatepage(
  * transaction as there is no space left for block reservation (typically why 
we
  * see a ENOSPC in writeback).
  */
-STATIC void
-xfs_aops_discard_page(
+static void
+xfs_discard_page(
        struct page             *page)
 {
        struct inode            *inode = page->mapping->host;
@@ -839,246 +567,14 @@ xfs_aops_discard_page(
        if (error && !XFS_FORCED_SHUTDOWN(mp))
                xfs_alert(mp, "page discard unable to remove delalloc 
mapping.");
 out_invalidate:
-       xfs_vm_invalidatepage(page, 0, PAGE_SIZE);
-}
-
-/*
- * We implement an immediate ioend submission policy here to avoid needing to
- * chain multiple ioends and hence nest mempool allocations which can violate
- * forward progress guarantees we need to provide. The current ioend we are
- * adding blocks to is cached on the writepage context, and if the new block
- * does not append to the cached ioend it will create a new ioend and cache 
that
- * instead.
- *
- * If a new ioend is created and cached, the old ioend is returned and queued
- * locally for submission once the entire page is processed or an error has 
been
- * detected.  While ioends are submitted immediately after they are completed,
- * batching optimisations are provided by higher level block plugging.
- *
- * At the end of a writeback pass, there will be a cached ioend remaining on 
the
- * writepage context that the caller will need to submit.
- */
-static int
-xfs_writepage_map(
-       struct xfs_writepage_ctx *wpc,
-       struct writeback_control *wbc,
-       struct inode            *inode,
-       struct page             *page,
-       uint64_t                end_offset)
-{
-       LIST_HEAD(submit_list);
-       struct iomap_page       *iop = to_iomap_page(page);
-       unsigned                len = i_blocksize(inode);
-       struct xfs_ioend        *ioend, *next;
-       uint64_t                file_offset;    /* file offset of page */
-       int                     error = 0, count = 0, i;
-
-       ASSERT(iop || i_blocksize(inode) == PAGE_SIZE);
-       ASSERT(!iop || atomic_read(&iop->write_count) == 0);
-
-       /*
-        * Walk through the page to find areas to write back. If we run off the
-        * end of the current map or find the current map invalid, grab a new
-        * one.
-        */
-       for (i = 0, file_offset = page_offset(page);
-            i < (PAGE_SIZE >> inode->i_blkbits) && file_offset < end_offset;
-            i++, file_offset += len) {
-               if (iop && !test_bit(i, iop->uptodate))
-                       continue;
-
-               error = xfs_map_blocks(wpc, inode, file_offset);
-               if (error)
-                       break;
-               if (wpc->iomap.type == IOMAP_HOLE)
-                       continue;
-               xfs_add_to_ioend(inode, file_offset, page, iop, wpc, wbc,
-                                &submit_list);
-               count++;
-       }
-
-       ASSERT(wpc->ioend || list_empty(&submit_list));
-       ASSERT(PageLocked(page));
-       ASSERT(!PageWriteback(page));
-
-       /*
-        * On error, we have to fail the ioend here because we may have set
-        * pages under writeback, we have to make sure we run IO completion to
-        * mark the error state of the IO appropriately, so we can't cancel the
-        * ioend directly here.  That means we have to mark this page as under
-        * writeback if we included any blocks from it in the ioend chain so
-        * that completion treats it correctly.
-        *
-        * If we didn't include the page in the ioend, the on error we can
-        * simply discard and unlock it as there are no other users of the page
-        * now.  The caller will still need to trigger submission of outstanding
-        * ioends on the writepage context so they are treated correctly on
-        * error.
-        */
-       if (unlikely(error)) {
-               if (!count) {
-                       xfs_aops_discard_page(page);
-                       ClearPageUptodate(page);
-                       unlock_page(page);
-                       goto done;
-               }
-
-               /*
-                * If the page was not fully cleaned, we need to ensure that the
-                * higher layers come back to it correctly.  That means we need
-                * to keep the page dirty, and for WB_SYNC_ALL writeback we need
-                * to ensure the PAGECACHE_TAG_TOWRITE index mark is not removed
-                * so another attempt to write this page in this writeback sweep
-                * will be made.
-                */
-               set_page_writeback_keepwrite(page);
-       } else {
-               clear_page_dirty_for_io(page);
-               set_page_writeback(page);
-       }
-
-       unlock_page(page);
-
-       /*
-        * Preserve the original error if there was one, otherwise catch
-        * submission errors here and propagate into subsequent ioend
-        * submissions.
-        */
-       list_for_each_entry_safe(ioend, next, &submit_list, io_list) {
-               int error2;
-
-               list_del_init(&ioend->io_list);
-               error2 = xfs_submit_ioend(wbc, ioend, error);
-               if (error2 && !error)
-                       error = error2;
-       }
-
-       /*
-        * We can end up here with no error and nothing to write only if we race
-        * with a partial page truncate on a sub-page block sized filesystem.
-        */
-       if (!count)
-               end_page_writeback(page);
-done:
-       mapping_set_error(page->mapping, error);
-       return error;
+       iomap_invalidatepage(page, 0, PAGE_SIZE);
 }
 
-/*
- * Write out a dirty page.
- *
- * For delalloc space on the page we need to allocate space and flush it.
- * For unwritten space on the page we need to start the conversion to
- * regular allocated space.
- */
-STATIC int
-xfs_do_writepage(
-       struct page             *page,
-       struct writeback_control *wbc,
-       void                    *data)
-{
-       struct xfs_writepage_ctx *wpc = data;
-       struct inode            *inode = page->mapping->host;
-       loff_t                  offset;
-       uint64_t              end_offset;
-       pgoff_t                 end_index;
-
-       trace_xfs_writepage(inode, page, 0, 0);
-
-       /*
-        * Refuse to write the page out if we are called from reclaim context.
-        *
-        * This avoids stack overflows when called from deeply used stacks in
-        * random callers for direct reclaim or memcg reclaim.  We explicitly
-        * allow reclaim from kswapd as the stack usage there is relatively low.
-        *
-        * This should never happen except in the case of a VM regression so
-        * warn about it.
-        */
-       if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) ==
-                       PF_MEMALLOC))
-               goto redirty;
-
-       /*
-        * Given that we do not allow direct reclaim to call us, we should
-        * never be called while in a filesystem transaction.
-        */
-       if (WARN_ON_ONCE(current->flags & PF_MEMALLOC_NOFS))
-               goto redirty;
-
-       /*
-        * Is this page beyond the end of the file?
-        *
-        * The page index is less than the end_index, adjust the end_offset
-        * to the highest offset that this page should represent.
-        * -----------------------------------------------------
-        * |                    file mapping           | <EOF> |
-        * -----------------------------------------------------
-        * | Page ... | Page N-2 | Page N-1 |  Page N  |       |
-        * ^--------------------------------^----------|--------
-        * |     desired writeback range    |      see else    |
-        * ---------------------------------^------------------|
-        */
-       offset = i_size_read(inode);
-       end_index = offset >> PAGE_SHIFT;
-       if (page->index < end_index)
-               end_offset = (xfs_off_t)(page->index + 1) << PAGE_SHIFT;
-       else {
-               /*
-                * Check whether the page to write out is beyond or straddles
-                * i_size or not.
-                * -------------------------------------------------------
-                * |            file mapping                    | <EOF>  |
-                * -------------------------------------------------------
-                * | Page ... | Page N-2 | Page N-1 |  Page N   | Beyond |
-                * ^--------------------------------^-----------|---------
-                * |                                |      Straddles     |
-                * ---------------------------------^-----------|--------|
-                */
-               unsigned offset_into_page = offset & (PAGE_SIZE - 1);
-
-               /*
-                * Skip the page if it is fully outside i_size, e.g. due to a
-                * truncate operation that is in progress. We must redirty the
-                * page so that reclaim stops reclaiming it. Otherwise
-                * xfs_vm_releasepage() is called on it and gets confused.
-                *
-                * Note that the end_index is unsigned long, it would overflow
-                * if the given offset is greater than 16TB on 32-bit system
-                * and if we do check the page is fully outside i_size or not
-                * via "if (page->index >= end_index + 1)" as "end_index + 1"
-                * will be evaluated to 0.  Hence this page will be redirtied
-                * and be written out repeatedly which would result in an
-                * infinite loop, the user program that perform this operation
-                * will hang.  Instead, we can verify this situation by checking
-                * if the page to write is totally beyond the i_size or if it's
-                * offset is just equal to the EOF.
-                */
-               if (page->index > end_index ||
-                   (page->index == end_index && offset_into_page == 0))
-                       goto redirty;
-
-               /*
-                * The page straddles i_size.  It must be zeroed out on each
-                * and every writepage invocation because it may be mmapped.
-                * "A file is mapped in multiples of the page size.  For a file
-                * that is not a multiple of the page size, the remaining
-                * memory is zeroed when mapped, and writes to that region are
-                * not written out to the file."
-                */
-               zero_user_segment(page, offset_into_page, PAGE_SIZE);
-
-               /* Adjust the end_offset to the end of file */
-               end_offset = offset;
-       }
-
-       return xfs_writepage_map(wpc, wbc, inode, page, end_offset);
-
-redirty:
-       redirty_page_for_writepage(wbc, page);
-       unlock_page(page);
-       return 0;
-}
+static const struct iomap_writeback_ops xfs_writeback_ops = {
+       .map_blocks             = xfs_map_blocks,
+       .submit_ioend           = xfs_submit_ioend,
+       .discard_page           = xfs_discard_page,
+};
 
 STATIC int
 xfs_vm_writepage(
@@ -1086,12 +582,8 @@ xfs_vm_writepage(
        struct writeback_control *wbc)
 {
        struct xfs_writepage_ctx wpc = { };
-       int                     ret;
 
-       ret = xfs_do_writepage(page, wbc, &wpc);
-       if (wpc.ioend)
-               ret = xfs_submit_ioend(wbc, wpc.ioend, ret);
-       return ret;
+       return iomap_writepage(page, wbc, &wpc.ctx, &xfs_writeback_ops);
 }
 
 STATIC int
@@ -1100,13 +592,9 @@ xfs_vm_writepages(
        struct writeback_control *wbc)
 {
        struct xfs_writepage_ctx wpc = { };
-       int                     ret;
 
        xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
-       ret = write_cache_pages(mapping, wbc, xfs_do_writepage, &wpc);
-       if (wpc.ioend)
-               ret = xfs_submit_ioend(wbc, wpc.ioend, ret);
-       return ret;
+       return iomap_writepages(mapping, wbc, &wpc.ctx, &xfs_writeback_ops);
 }
 
 STATIC int
@@ -1119,15 +607,6 @@ xfs_dax_writepages(
                        xfs_find_bdev_for_inode(mapping->host), wbc);
 }
 
-STATIC int
-xfs_vm_releasepage(
-       struct page             *page,
-       gfp_t                   gfp_mask)
-{
-       trace_xfs_releasepage(page->mapping->host, page, 0, 0);
-       return iomap_releasepage(page, gfp_mask);
-}
-
 STATIC sector_t
 xfs_vm_bmap(
        struct address_space    *mapping,
@@ -1185,8 +664,8 @@ const struct address_space_operations 
xfs_address_space_operations = {
        .writepage              = xfs_vm_writepage,
        .writepages             = xfs_vm_writepages,
        .set_page_dirty         = iomap_set_page_dirty,
-       .releasepage            = xfs_vm_releasepage,
-       .invalidatepage         = xfs_vm_invalidatepage,
+       .releasepage            = iomap_releasepage,
+       .invalidatepage         = iomap_invalidatepage,
        .bmap                   = xfs_vm_bmap,
        .direct_IO              = noop_direct_IO,
        .migratepage            = iomap_migrate_page,
diff --git a/fs/xfs/xfs_aops.h b/fs/xfs/xfs_aops.h
index c2756ed50b0d..687b11f34fa2 100644
--- a/fs/xfs/xfs_aops.h
+++ b/fs/xfs/xfs_aops.h
@@ -6,23 +6,6 @@
 #ifndef __XFS_AOPS_H__
 #define __XFS_AOPS_H__
 
-extern struct bio_set xfs_ioend_bioset;
-
-/*
- * Structure for buffered I/O completions.
- */
-struct xfs_ioend {
-       struct list_head        io_list;        /* next ioend in chain */
-       u16                     io_type;
-       u16                     io_flags;       /* IOMAP_F_* */
-       struct inode            *io_inode;      /* file being written to */
-       size_t                  io_size;        /* size of the extent */
-       xfs_off_t               io_offset;      /* offset in the file */
-       struct xfs_trans        *io_append_trans;/* xact. for size update */
-       struct bio              *io_bio;        /* bio being built */
-       struct bio              io_inline_bio;  /* MUST BE LAST! */
-};
-
 extern const struct address_space_operations xfs_address_space_operations;
 extern const struct address_space_operations xfs_dax_aops;
 
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 8d1df9f8be07..0a8cf6b87a21 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -40,7 +40,6 @@
 #include <linux/parser.h>
 
 static const struct super_operations xfs_super_operations;
-struct bio_set xfs_ioend_bioset;
 
 static struct kset *xfs_kset;          /* top-level xfs sysfs dir */
 #ifdef DEBUG
@@ -1853,15 +1852,10 @@ MODULE_ALIAS_FS("xfs");
 STATIC int __init
 xfs_init_zones(void)
 {
-       if (bioset_init(&xfs_ioend_bioset, 4 * (PAGE_SIZE / SECTOR_SIZE),
-                       offsetof(struct xfs_ioend, io_inline_bio),
-                       BIOSET_NEED_BVECS))
-               goto out;
-
        xfs_log_ticket_zone = kmem_zone_init(sizeof(xlog_ticket_t),
                                                "xfs_log_ticket");
        if (!xfs_log_ticket_zone)
-               goto out_free_ioend_bioset;
+               goto out;
 
        xfs_bmap_free_item_zone = kmem_zone_init(
                        sizeof(struct xfs_extent_free_item),
@@ -1996,8 +1990,6 @@ xfs_init_zones(void)
        kmem_zone_destroy(xfs_bmap_free_item_zone);
  out_destroy_log_ticket_zone:
        kmem_zone_destroy(xfs_log_ticket_zone);
- out_free_ioend_bioset:
-       bioset_exit(&xfs_ioend_bioset);
  out:
        return -ENOMEM;
 }
@@ -2028,7 +2020,6 @@ xfs_destroy_zones(void)
        kmem_zone_destroy(xfs_btree_cur_zone);
        kmem_zone_destroy(xfs_bmap_free_item_zone);
        kmem_zone_destroy(xfs_log_ticket_zone);
-       bioset_exit(&xfs_ioend_bioset);
 }
 
 STATIC int __init
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index eae4b29c174e..cbb23d7a3554 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -1158,45 +1158,6 @@ DEFINE_RW_EVENT(xfs_file_buffered_write);
 DEFINE_RW_EVENT(xfs_file_direct_write);
 DEFINE_RW_EVENT(xfs_file_dax_write);
 
-DECLARE_EVENT_CLASS(xfs_page_class,
-       TP_PROTO(struct inode *inode, struct page *page, unsigned long off,
-                unsigned int len),
-       TP_ARGS(inode, page, off, len),
-       TP_STRUCT__entry(
-               __field(dev_t, dev)
-               __field(xfs_ino_t, ino)
-               __field(pgoff_t, pgoff)
-               __field(loff_t, size)
-               __field(unsigned long, offset)
-               __field(unsigned int, length)
-       ),
-       TP_fast_assign(
-               __entry->dev = inode->i_sb->s_dev;
-               __entry->ino = XFS_I(inode)->i_ino;
-               __entry->pgoff = page_offset(page);
-               __entry->size = i_size_read(inode);
-               __entry->offset = off;
-               __entry->length = len;
-       ),
-       TP_printk("dev %d:%d ino 0x%llx pgoff 0x%lx size 0x%llx offset %lx "
-                 "length %x",
-                 MAJOR(__entry->dev), MINOR(__entry->dev),
-                 __entry->ino,
-                 __entry->pgoff,
-                 __entry->size,
-                 __entry->offset,
-                 __entry->length)
-)
-
-#define DEFINE_PAGE_EVENT(name)                \
-DEFINE_EVENT(xfs_page_class, name,     \
-       TP_PROTO(struct inode *inode, struct page *page, unsigned long off, \
-                unsigned int len),     \
-       TP_ARGS(inode, page, off, len))
-DEFINE_PAGE_EVENT(xfs_writepage);
-DEFINE_PAGE_EVENT(xfs_releasepage);
-DEFINE_PAGE_EVENT(xfs_invalidatepage);
-
 DECLARE_EVENT_CLASS(xfs_imap_class,
        TP_PROTO(struct xfs_inode *ip, xfs_off_t offset, ssize_t count,
                 int whichfork, struct xfs_bmbt_irec *irec),
-- 
2.20.1

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