On Sun, Oct 06, 2019 at 05:46:07PM +0200, Christoph Hellwig wrote:
> 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>

Looks ok,
Reviewed-by: Darrick J. Wong <darrick.w...@oracle.com>

--D

> ---
>  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, 78 insertions(+), 656 deletions(-)
> 
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index 8c101081e3b1..807af5c3c347 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;
> @@ -269,43 +209,20 @@ 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)
> +static inline bool xfs_ioend_needs_workqueue(struct iomap_ioend *ioend)
>  {
> -     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;
> +     return ioend->io_private ||
> +             ioend->io_type == IOMAP_UNWRITTEN ||
> +             (ioend->io_flags & IOMAP_F_SHARED);
>  }
>  
>  /*
> @@ -315,80 +232,38 @@ 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 +272,18 @@ 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));
> +     ASSERT(xfs_ioend_needs_workqueue(ioend));
> +
> +     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 +292,7 @@ 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 +314,10 @@ 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 +332,18 @@ 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 +353,7 @@ 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 +361,9 @@ 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 +419,7 @@ 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 +442,7 @@ 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 +506,9 @@ 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 +531,14 @@ 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 (xfs_ioend_needs_workqueue(ioend))
> +             ioend->io_bio->bi_end_io = xfs_end_bio;
> +     return status;
>  }
>  
>  /*
> @@ -816,8 +552,8 @@ 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 +575,14 @@ 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);
> +     iomap_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;
> -}
> -
> -/*
> - * 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 +590,8 @@ 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 +600,9 @@ 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 +615,6 @@ 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 +672,8 @@ 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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