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SubjectRe: [PATCH 11/12] iomap: move the xfs writeback code to iomap.c
On Mon, Jun 24, 2019 at 07:52:52AM +0200, Christoph Hellwig wrote:
> Takes the xfs writeback code and move it to iomap.c. A new structure
> with three methods is added as the abstraction from the generic
> writeback code to the file system. These methods are used to map
> blocks, submit an ioend, and cancel a page that encountered an error
> before it was added to an ioend.
>
> Note that we temporarily lose the writepage tracing, but that will
> be added back soon.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> fs/iomap.c | 521 ++++++++++++++++++++++++++++++++++++-
> fs/xfs/xfs_aops.c | 584 ++++--------------------------------------
> fs/xfs/xfs_aops.h | 16 --
> fs/xfs/xfs_super.c | 11 +-
> include/linux/iomap.h | 41 +++
> 5 files changed, 605 insertions(+), 568 deletions(-)
>
> diff --git a/fs/iomap.c b/fs/iomap.c
> index 23ef63fd1669..72a1b622e634 100644
> --- a/fs/iomap.c
> +++ b/fs/iomap.c
> @@ -1,7 +1,7 @@
> // SPDX-License-Identifier: GPL-2.0
> /*
> * Copyright (C) 2010 Red Hat, Inc.
> - * Copyright (c) 2016-2018 Christoph Hellwig.
> + * Copyright (c) 2016-2019 Christoph Hellwig.
> */
> #include <linux/module.h>
> #include <linux/compiler.h>
> @@ -12,6 +12,7 @@
> #include <linux/migrate.h>
> #include <linux/mm.h>
> #include <linux/mm_inline.h>
> +#include <linux/list_sort.h>
> #include <linux/swap.h>
> #include <linux/pagemap.h>
> #include <linux/pagevec.h>
> @@ -25,6 +26,8 @@
>
> #include "internal.h"
>
> +static struct bio_set iomap_ioend_bioset;
> +
> /*
> * Execute a iomap write on a segment of the mapping that spans a
> * contiguous range of pages that have identical block mapping state.
> @@ -2192,3 +2195,519 @@ iomap_bmap(struct address_space *mapping, sector_t bno,

This looks like a straight code copy from fs/xfs/ into fs/iomap.c.
That's fine with me, but seeing as this file is now ~2700 lines long,
perhaps we should break this up among major functional lines?

Looking at fs/iomap.c, I see...

* Basic iomap iterator functions (~40 lines)
* Page cache management (readpage*, write, mkwrite) (~860 lines)
* Zeroing (~80 lines)
* FIEMAP and seek hole / seek data (~300 lines)
* directio (~500 lines)
* swapfiles (~170 lines)
* and now, page cache writeback (~520 lines)

If I have spare time this week (ha ha) I'll see if I can break all this
up (as a separate patch series), so for this:

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> return bno;
> }
> EXPORT_SYMBOL_GPL(iomap_bmap);
> +
> +static void
> +iomap_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);
> + }
> +
> + WARN_ON_ONCE(i_blocksize(inode) < PAGE_SIZE && !iop);
> + WARN_ON_ONCE(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.
> + */
> +void
> +iomap_finish_ioend(struct iomap_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)
> + iomap_finish_page_writeback(inode, bvec, error);
> + bio_put(bio);
> + }
> +
> + if (unlikely(error && !quiet)) {
> + printk_ratelimited(KERN_ERR
> + "%s: writeback error on sector %llu",
> + inode->i_sb->s_id, start);
> + }
> +}
> +EXPORT_SYMBOL_GPL(iomap_finish_ioend);
> +
> +void
> +iomap_finish_ioends(struct iomap_ioend *ioend, int error)
> +{
> + struct list_head tmp;
> +
> + list_replace_init(&ioend->io_list, &tmp);
> + iomap_finish_ioend(ioend, error);
> + while ((ioend = list_pop(&tmp, struct iomap_ioend, io_list)))
> + iomap_finish_ioend(ioend, error);
> +}
> +EXPORT_SYMBOL_GPL(iomap_finish_ioends);
> +
> +/*
> + * We can merge two adjacent ioends if they have the same set of work to do.
> + */
> +static bool
> +iomap_ioend_can_merge(struct iomap_ioend *ioend, struct iomap_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;
> +}
> +
> +void
> +iomap_ioend_try_merge(struct iomap_ioend *ioend, struct list_head *more_ioends)
> +{
> + struct iomap_ioend *next;
> +
> + INIT_LIST_HEAD(&ioend->io_list);
> +
> + while ((next = list_first_entry_or_null(more_ioends, struct iomap_ioend,
> + io_list))) {
> + if (!iomap_ioend_can_merge(ioend, next))
> + break;
> + list_move_tail(&next->io_list, &ioend->io_list);
> + ioend->io_size += next->io_size;
> + }
> +}
> +EXPORT_SYMBOL_GPL(iomap_ioend_try_merge);
> +
> +static int
> +iomap_ioend_compare(void *priv, struct list_head *a, struct list_head *b)
> +{
> + struct iomap_ioend *ia, *ib;
> +
> + ia = container_of(a, struct iomap_ioend, io_list);
> + ib = container_of(b, struct iomap_ioend, io_list);
> + if (ia->io_offset < ib->io_offset)
> + return -1;
> + else if (ia->io_offset > ib->io_offset)
> + return 1;
> + return 0;
> +}
> +
> +void
> +iomap_sort_ioends(struct list_head *ioend_list)
> +{
> + list_sort(NULL, ioend_list, iomap_ioend_compare);
> +}
> +EXPORT_SYMBOL_GPL(iomap_sort_ioends);
> +
> +/*
> + * 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 @error 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
> +iomap_submit_ioend(struct iomap_writepage_ctx *wpc, struct iomap_ioend *ioend,
> + int error)
> +{
> + /*
> + * 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.
> + */
> + ioend->io_bio->bi_private = ioend;
> + error = wpc->ops->submit_ioend(ioend, error);
> + if (error) {
> + ioend->io_bio->bi_status = errno_to_blk_status(error);
> + bio_endio(ioend->io_bio);
> + return error;
> + }
> +
> + submit_bio(ioend->io_bio);
> + return 0;
> +}
> +
> +static struct iomap_ioend *
> +iomap_alloc_ioend(struct inode *inode, struct iomap_writepage_ctx *wpc,
> + loff_t offset, sector_t sector, struct writeback_control *wbc)
> +{
> + struct iomap_ioend *ioend;
> + struct bio *bio;
> +
> + bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, &iomap_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;
> +
> + ioend = container_of(bio, struct iomap_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_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 iomap_finish_ioend().
> + */
> +static struct bio *
> +iomap_chain_bio(struct bio *prev)
> +{
> + struct bio *new;
> +
> + new = bio_alloc(GFP_NOFS, BIO_MAX_PAGES);
> + bio_copy_dev(new, prev);
> + 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 iomap_finish_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
> +iomap_add_to_ioend(struct inode *inode, loff_t offset, struct page *page,
> + struct iomap_page *iop, struct iomap_writepage_ctx *wpc,
> + struct writeback_control *wbc, struct list_head *iolist)
> +{
> + unsigned len = i_blocksize(inode);
> + unsigned poff = offset & (PAGE_SIZE - 1);
> + sector_t sector = iomap_sector(&wpc->iomap, offset);
> +
> + 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 = iomap_alloc_ioend(inode, wpc, offset, sector, wbc);
> + }
> +
> + if (!__bio_try_merge_page(wpc->ioend->io_bio, page, len, poff, true)) {
> + if (iop)
> + atomic_inc(&iop->write_count);
> + if (bio_full(wpc->ioend->io_bio)) {
> + wpc->ioend->io_bio =
> + iomap_chain_bio(wpc->ioend->io_bio);
> + }
> + bio_add_page(wpc->ioend->io_bio, page, len, poff);
> + }
> +
> + wpc->ioend->io_size += len;
> +}
> +
> +/*
> + * 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
> +iomap_writepage_map(struct iomap_writepage_ctx *wpc,
> + struct writeback_control *wbc, struct inode *inode,
> + struct page *page, u64 end_offset)
> +{
> + struct iomap_page *iop = to_iomap_page(page);
> + struct iomap_ioend *ioend, *next;
> + unsigned len = i_blocksize(inode);
> + u64 file_offset; /* file offset of page */
> + int error = 0, count = 0, i;
> + LIST_HEAD(submit_list);
> +
> + WARN_ON_ONCE(i_blocksize(inode) < PAGE_SIZE && !iop);
> + WARN_ON_ONCE(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 = wpc->ops->map_blocks(wpc, inode, file_offset);
> + if (error)
> + break;
> + if (wpc->iomap.type == IOMAP_HOLE)
> + continue;
> + iomap_add_to_ioend(inode, file_offset, page, iop, wpc, wbc,
> + &submit_list);
> + count++;
> + }
> +
> + WARN_ON_ONCE(!wpc->ioend && !list_empty(&submit_list));
> + WARN_ON_ONCE(!PageLocked(page));
> + WARN_ON_ONCE(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) {
> + wpc->ops->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 = iomap_submit_ioend(wpc, 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
> +iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
> +{
> + struct iomap_writepage_ctx *wpc = data;
> + struct inode *inode = page->mapping->host;
> + pgoff_t end_index;
> + u64 end_offset;
> + loff_t offset;
> +
> + /*
> + * 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 = (loff_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
> + * iomap_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 iomap_writepage_map(wpc, wbc, inode, page, end_offset);
> +
> +redirty:
> + redirty_page_for_writepage(wbc, page);
> + unlock_page(page);
> + return 0;
> +}
> +
> +int
> +iomap_writepage(struct page *page, struct writeback_control *wbc,
> + struct iomap_writepage_ctx *wpc,
> + const struct iomap_writeback_ops *ops)
> +{
> + int ret;
> +
> + wpc->ops = ops;
> + ret = iomap_do_writepage(page, wbc, wpc);
> + if (!wpc->ioend)
> + return ret;
> + return iomap_submit_ioend(wpc, wpc->ioend, ret);
> +}
> +EXPORT_SYMBOL_GPL(iomap_writepage);
> +
> +int
> +iomap_writepages(struct address_space *mapping, struct writeback_control *wbc,
> + struct iomap_writepage_ctx *wpc,
> + const struct iomap_writeback_ops *ops)
> +{
> + int ret;
> +
> + wpc->ops = ops;
> + ret = write_cache_pages(mapping, wbc, iomap_do_writepage, wpc);
> + if (!wpc->ioend)
> + return ret;
> + return iomap_submit_ioend(wpc, wpc->ioend, ret);
> +}
> +EXPORT_SYMBOL_GPL(iomap_writepages);
> +
> +static int __init iomap_init(void)
> +{
> + return bioset_init(&iomap_ioend_bioset, 4 * (PAGE_SIZE / SECTOR_SIZE),
> + offsetof(struct iomap_ioend, io_inline_bio),
> + BIOSET_NEED_BVECS);
> +}
> +fs_initcall(iomap_init);
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index d9a7a9e6b912..26b838aea2db 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -23,16 +23,18 @@
> #include "xfs_reflink.h"
> #include <linux/writeback.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)
> @@ -59,84 +61,10 @@ 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);
> - }
> -}
> -
> -static void
> -xfs_destroy_ioends(
> - struct xfs_ioend *ioend,
> - int error)
> -{
> - struct list_head tmp;
> -
> - list_replace_init(&ioend->io_list, &tmp);
> - xfs_destroy_ioend(ioend, error);
> - while ((ioend = list_pop(&tmp, struct xfs_ioend, io_list)))
> - xfs_destroy_ioend(ioend, error);
> -}
> -
> /*
> * 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;
> @@ -182,7 +110,7 @@ xfs_setfilesize(
> */
> STATIC void
> xfs_end_ioend(
> - struct xfs_ioend *ioend)
> + struct iomap_ioend *ioend)
> {
> unsigned int nofs_flag = memalloc_nofs_save();
> struct xfs_inode *ip = XFS_I(ioend->io_inode);
> @@ -218,76 +146,10 @@ xfs_end_ioend(
> if (!error && xfs_ioend_is_append(ioend))
> error = xfs_setfilesize(ip, offset, size);
> done:
> - xfs_destroy_ioends(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;
> -}
> -
> -/* Try to merge adjacent completions. */
> -STATIC void
> -xfs_ioend_try_merge(
> - struct xfs_ioend *ioend,
> - struct list_head *more_ioends)
> -{
> - struct xfs_ioend *next;
> -
> - INIT_LIST_HEAD(&ioend->io_list);
> -
> - while ((next = list_first_entry_or_null(more_ioends, struct xfs_ioend,
> - io_list))) {
> - if (!xfs_ioend_can_merge(ioend, next))
> - break;
> - list_move_tail(&next->io_list, &ioend->io_list);
> - ioend->io_size += next->io_size;
> - }
> -}
> -
> -/* 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;
> -}
> -
> -static void
> -xfs_sort_ioends(
> - struct list_head *ioend_list)
> -{
> - list_sort(NULL, ioend_list, xfs_ioend_compare);
> -}
> -
> /* Finish all pending io completions. */
> void
> xfs_end_io(
> @@ -295,7 +157,7 @@ xfs_end_io(
> {
> struct xfs_inode *ip =
> container_of(work, struct xfs_inode, i_ioend_work);
> - struct xfs_ioend *ioend;
> + struct iomap_ioend *ioend;
> struct list_head tmp;
> unsigned long flags;
>
> @@ -303,9 +165,9 @@ xfs_end_io(
> list_replace_init(&ip->i_ioend_list, &tmp);
> spin_unlock_irqrestore(&ip->i_ioend_lock, flags);
>
> - xfs_sort_ioends(&tmp);
> - while ((ioend = list_pop(&tmp, struct xfs_ioend, io_list))) {
> - xfs_ioend_try_merge(ioend, &tmp);
> + iomap_sort_ioends(&tmp);
> + while ((ioend = list_pop(&tmp, struct iomap_ioend, io_list))) {
> + iomap_ioend_try_merge(ioend, &tmp);
> xfs_end_ioend(ioend);
> }
> }
> @@ -314,7 +176,7 @@ 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;
> @@ -329,7 +191,7 @@ xfs_end_bio(
> 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));
> + iomap_finish_ioend(ioend, blk_status_to_errno(bio->bi_status));
> }
>
> /*
> @@ -338,7 +200,7 @@ 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)
> {
> @@ -360,10 +222,10 @@ 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;
> }
> @@ -378,12 +240,18 @@ 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
> @@ -393,8 +261,7 @@ 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);
> @@ -402,9 +269,9 @@ 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)
> {
> @@ -460,7 +327,7 @@ 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;
> @@ -483,7 +350,7 @@ 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? */
> @@ -547,24 +414,9 @@ 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)
> {
> /* Convert CoW extents to regular */
> @@ -584,118 +436,8 @@ xfs_submit_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;
> -
> - 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_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);
> - 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)
> -{
> - unsigned len = i_blocksize(inode);
> - unsigned poff = offset & (PAGE_SIZE - 1);
> - sector_t sector;
> -
> - sector = (wpc->iomap.addr + offset - wpc->iomap.offset) >> 9;
> -
> - 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);
> - }
> -
> - if (!__bio_try_merge_page(wpc->ioend->io_bio, page, len, poff, true)) {
> - if (iop)
> - atomic_inc(&iop->write_count);
> - if (bio_full(wpc->ioend->io_bio))
> - 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;
> + return status;
> }
>
> STATIC void
> @@ -719,8 +461,8 @@ 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;
> @@ -745,243 +487,11 @@ xfs_aops_discard_page(
> 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;
> -}
> -
> -/*
> - * 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(
> @@ -989,12 +499,8 @@ 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
> @@ -1003,13 +509,9 @@ 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
> diff --git a/fs/xfs/xfs_aops.h b/fs/xfs/xfs_aops.h
> index bf95837c59af..26a7772d4b81 100644
> --- a/fs/xfs/xfs_aops.h
> +++ b/fs/xfs/xfs_aops.h
> @@ -6,22 +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;
> - 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 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 594c119824cc..52b89e175bc5 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -53,7 +53,6 @@
> #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
> @@ -1870,15 +1869,10 @@ 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),
> @@ -2013,8 +2007,6 @@ 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;
> }
> @@ -2045,7 +2037,6 @@ 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/include/linux/iomap.h b/include/linux/iomap.h
> index 2103b94cb1bf..e87f44810c53 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -4,6 +4,7 @@
>
> #include <linux/atomic.h>
> #include <linux/bitmap.h>
> +#include <linux/blk_types.h>
> #include <linux/mm.h>
> #include <linux/types.h>
> #include <linux/mm_types.h>
> @@ -11,6 +12,7 @@
> struct address_space;
> struct fiemap_extent_info;
> struct inode;
> +struct iomap_writepage_ctx;
> struct iov_iter;
> struct kiocb;
> struct page;
> @@ -165,6 +167,45 @@ loff_t iomap_seek_data(struct inode *inode, loff_t offset,
> sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
> const struct iomap_ops *ops);
>
> +/*
> + * Structure for writeback I/O completions.
> + */
> +struct iomap_ioend {
> + struct list_head io_list; /* next ioend in chain */
> + u16 io_type;
> + u16 io_flags;
> + struct inode *io_inode; /* file being written to */
> + size_t io_size; /* size of the extent */
> + loff_t io_offset; /* offset in the file */
> + struct bio *io_bio; /* bio being built */
> + struct bio io_inline_bio; /* MUST BE LAST! */
> +};
> +
> +struct iomap_writeback_ops {
> + int (*map_blocks)(struct iomap_writepage_ctx *wpc, struct inode *inode,
> + loff_t offset);
> + int (*submit_ioend)(struct iomap_ioend *ioend, int status);
> + void (*discard_page)(struct page *page);
> +};
> +
> +struct iomap_writepage_ctx {
> + struct iomap iomap;
> + struct iomap_ioend *ioend;
> + const struct iomap_writeback_ops *ops;
> +};
> +
> +void iomap_finish_ioend(struct iomap_ioend *ioend, int error);
> +void iomap_finish_ioends(struct iomap_ioend *ioend, int error);
> +void iomap_ioend_try_merge(struct iomap_ioend *ioend,
> + struct list_head *more_ioends);
> +void iomap_sort_ioends(struct list_head *ioend_list);
> +int iomap_writepage(struct page *page, struct writeback_control *wbc,
> + struct iomap_writepage_ctx *wpc,
> + const struct iomap_writeback_ops *ops);
> +int iomap_writepages(struct address_space *mapping,
> + struct writeback_control *wbc, struct iomap_writepage_ctx *wpc,
> + const struct iomap_writeback_ops *ops);
> +
> /*
> * Flags for direct I/O ->end_io:
> */
> --
> 2.20.1
>

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