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Message-ID: <20191015184040.GU13108@magnolia>
Date: Tue, 15 Oct 2019 11:40:40 -0700
From: "Darrick J. Wong" <darrick.wong@...cle.com>
To: Christoph Hellwig <hch@....de>
Cc: Damien Le Moal <Damien.LeMoal@....com>,
Andreas Gruenbacher <agruenba@...hat.com>,
linux-xfs@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 09/12] iomap: lift the xfs writeback code to iomap
On Tue, Oct 15, 2019 at 05:43:42PM +0200, Christoph Hellwig wrote:
> Take the xfs writeback code and move it to fs/iomap. 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.
>
> Signed-off-by: Christoph Hellwig <hch@....de>
> ---
> fs/iomap/buffered-io.c | 564 ++++++++++++++++++++++++++++++++++-
> fs/iomap/trace.h | 39 +++
> fs/xfs/xfs_aops.c | 662 ++++-------------------------------------
> fs/xfs/xfs_aops.h | 17 --
> fs/xfs/xfs_super.c | 11 +-
> fs/xfs/xfs_trace.h | 39 ---
> include/linux/iomap.h | 59 ++++
> 7 files changed, 722 insertions(+), 669 deletions(-)
>
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index d1620c3f2a4c..00af08006cd3 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
<snip>
> @@ -1084,3 +1091,558 @@ vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops)
> return block_page_mkwrite_return(ret);
> }
> EXPORT_SYMBOL_GPL(iomap_page_mkwrite);
> +
> +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.
> + */
> +static 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);
Ugh, /this/ message. It's pretty annoying how it doesn't tell you which
file or where in that file the write was lost.
I want to send in a patch atop your series to fix this, though I'm a
also little inclined to want to keep the message inside XFS.
Thoughts?
<snip>
> +/*
> + * 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)
> +{
> + ioend->io_bio->bi_private = ioend;
> + ioend->io_bio->bi_end_io = iomap_writepage_end_bio;
> +
> + if (wpc->ops->submit_ioend)
> + error = wpc->ops->submit_ioend(ioend, error);
IIRC, Brian complained about this name ^^^^^^ in a previous vesrion.
I think the documentation in the ops structure definition makes it clear
that "submit_ioend" is really a pre-submission hook. Everyone ok with
that?
(Everything else in the patch looks ok.)
--D
> + if (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_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;
> + wbc_init_bio(wbc, bio);
> +
> + 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_private = 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 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);/* 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 iomap_finish_ioend */
> + submit_bio(prev);
> + return new;
> +}
> +
> +static bool
> +iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t offset,
> + sector_t sector)
> +{
> + if ((wpc->iomap.flags & IOMAP_F_SHARED) !=
> + (wpc->ioend->io_flags & IOMAP_F_SHARED))
> + return false;
> + if (wpc->iomap.type != wpc->ioend->io_type)
> + return false;
> + if (offset != wpc->ioend->io_offset + wpc->ioend->io_size)
> + return false;
> + if (sector != bio_end_sector(wpc->ioend->io_bio))
> + return false;
> + return true;
> +}
> +
> +/*
> + * 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)
> +{
> + 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 || !iomap_can_add_to_ioend(wpc, offset, sector)) {
> + if (wpc->ioend)
> + list_add(&wpc->ioend->io_list, iolist);
> + wpc->ioend = iomap_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 =
> + iomap_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);
> +}
> +
> +/*
> + * 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) {
> + if (wpc->ops->discard_page)
> + 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;
> +
> + trace_iomap_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 = (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/iomap/trace.h b/fs/iomap/trace.h
> index 3900de1d871d..3bc8d0263020 100644
> --- a/fs/iomap/trace.h
> +++ b/fs/iomap/trace.h
> @@ -41,6 +41,45 @@ DEFINE_EVENT(iomap_readpage_class, name, \
> DEFINE_READPAGE_EVENT(iomap_readpage);
> DEFINE_READPAGE_EVENT(iomap_readpages);
>
> +DECLARE_EVENT_CLASS(iomap_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(u64, 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 = 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(iomap_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(iomap_writepage);
> +DEFINE_PAGE_EVENT(iomap_releasepage);
> +DEFINE_PAGE_EVENT(iomap_invalidatepage);
> +
> #endif /* _IOMAP_TRACE_H */
>
> #undef TRACE_INCLUDE_PATH
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index e2033b070f4a..546bd8a48cad 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)
> @@ -54,87 +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);
> - }
> -}
> -
> -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_first_entry_or_null(&tmp, struct xfs_ioend,
> - io_list))) {
> - list_del_init(&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;
> @@ -142,7 +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;
> @@ -215,7 +140,7 @@ 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);
> @@ -243,7 +168,7 @@ xfs_setfilesize_ioend(
> */
> STATIC void
> xfs_end_ioend(
> - struct xfs_ioend *ioend)
> + struct iomap_ioend *ioend)
> {
> struct xfs_inode *ip = XFS_I(ioend->io_inode);
> xfs_off_t offset = ioend->io_offset;
> @@ -289,31 +214,10 @@ xfs_end_ioend(
> done:
> if (ioend->io_private)
> error = xfs_setfilesize_ioend(ioend, error);
> - 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;
> -}
> -
> /*
> * 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
> @@ -322,8 +226,8 @@ xfs_ioend_can_merge(
> */
> static void
> xfs_ioend_merge_private(
> - struct xfs_ioend *ioend,
> - struct xfs_ioend *next)
> + struct iomap_ioend *ioend,
> + struct iomap_ioend *next)
> {
> if (!ioend->io_private) {
> ioend->io_private = next->io_private;
> @@ -333,53 +237,6 @@ xfs_ioend_merge_private(
> }
> }
>
> -/* 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;
> - if (next->io_private)
> - xfs_ioend_merge_private(ioend, next);
> - }
> -}
> -
> -/* 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(
> @@ -387,7 +244,7 @@ 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;
>
> @@ -395,16 +252,16 @@ 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_first_entry_or_null(&tmp, struct xfs_ioend,
> + iomap_sort_ioends(&tmp);
> + while ((ioend = list_first_entry_or_null(&tmp, struct iomap_ioend,
> io_list))) {
> list_del_init(&ioend->io_list);
> - xfs_ioend_try_merge(ioend, &tmp);
> + iomap_ioend_try_merge(ioend, &tmp, xfs_ioend_merge_private);
> xfs_end_ioend(ioend);
> }
> }
>
> -static inline bool xfs_ioend_needs_workqueue(struct xfs_ioend *ioend)
> +static inline bool xfs_ioend_needs_workqueue(struct iomap_ioend *ioend)
> {
> return ioend->io_private ||
> ioend->io_type == IOMAP_UNWRITTEN ||
> @@ -415,20 +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 (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(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);
> }
>
> /*
> @@ -437,7 +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)
> {
> @@ -459,10 +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;
> }
> @@ -477,12 +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
> @@ -492,8 +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);
> @@ -501,9 +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)
> {
> @@ -559,7 +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;
> @@ -582,7 +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? */
> @@ -645,24 +505,9 @@ 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;
> @@ -690,147 +535,9 @@ 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;
> - 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_private = 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;
> -}
> -
> -static bool
> -xfs_can_add_to_ioend(
> - struct xfs_writepage_ctx *wpc,
> - xfs_off_t offset,
> - sector_t sector)
> -{
> - if ((wpc->iomap.flags & IOMAP_F_SHARED) !=
> - (wpc->ioend->io_flags & IOMAP_F_SHARED))
> - return false;
> - if (wpc->iomap.type != wpc->ioend->io_type)
> - return false;
> - if (offset != wpc->ioend->io_offset + wpc->ioend->io_size)
> - return false;
> - if (sector != bio_end_sector(wpc->ioend->io_bio))
> - return false;
> - return true;
> -}
> -
> -/*
> - * 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 || !xfs_can_add_to_ioend(wpc, offset, sector)) {
> - 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;
> }
>
> /*
> @@ -844,8 +551,8 @@ 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;
> @@ -867,246 +574,14 @@ 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(
> @@ -1114,12 +589,8 @@ 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
> @@ -1128,13 +599,9 @@ 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
> @@ -1147,15 +614,6 @@ 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,
> @@ -1213,8 +671,8 @@ 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 4a0226cdad4f..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 */
> - void *io_private; /* file system private data */
> - 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),
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index 7aa5d6117936..0b399718c387 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>
> @@ -12,6 +13,7 @@
> struct address_space;
> struct fiemap_extent_info;
> struct inode;
> +struct iomap_writepage_ctx;
> struct iov_iter;
> struct kiocb;
> struct page;
> @@ -183,6 +185,63 @@ 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; /* IOMAP_F_* */
> + struct inode *io_inode; /* file being written to */
> + size_t io_size; /* size of the extent */
> + loff_t io_offset; /* offset in the file */
> + void *io_private; /* file system private data */
> + struct bio *io_bio; /* bio being built */
> + struct bio io_inline_bio; /* MUST BE LAST! */
> +};
> +
> +struct iomap_writeback_ops {
> + /*
> + * Required, maps the blocks so that writeback can be performed on
> + * the range starting at offset.
> + */
> + int (*map_blocks)(struct iomap_writepage_ctx *wpc, struct inode *inode,
> + loff_t offset);
> +
> + /*
> + * Optional, allows the file systems to perform actions just before
> + * submitting the bio and/or override the bio end_io handler for complex
> + * operations like copy on write extent manipulation or unwritten extent
> + * conversions.
> + */
> + int (*submit_ioend)(struct iomap_ioend *ioend, int status);
> +
> + /*
> + * Optional, allows the file system to discard state on a page where
> + * we failed to submit any I/O.
> + */
> + 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_ioends(struct iomap_ioend *ioend, int error);
> +void iomap_ioend_try_merge(struct iomap_ioend *ioend,
> + struct list_head *more_ioends,
> + void (*merge_private)(struct iomap_ioend *ioend,
> + struct iomap_ioend *next));
> +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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