Commit cd57b771 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Theodore Ts'o
Browse files

ext4: Convert ext4_bio_write_page() to use a folio 



Remove several calls to compound_head() and the last caller of
set_page_writeback_keepwrite(), so remove the wrapper too.

Also export bio_add_folio() as this is the first caller from a module.

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarRitesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: default avatarTheodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20230324180129.1220691-4-willy@infradead.org


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent c76e14dc

block/bio.c

+1 −0
Original line number Diff line number Diff line
@@ -1159,6 +1159,7 @@ bool bio_add_folio(struct bio *bio, struct folio *folio, size_t len, 
		return false;

	return bio_add_page(bio, &folio->page, len, off) > 0;

}

EXPORT_SYMBOL(bio_add_folio);



void __bio_release_pages(struct bio *bio, bool mark_dirty)

{

fs/ext4/page-io.c

+27 −31
Original line number Diff line number Diff line
@@ -409,12 +409,10 @@ static void io_submit_init_bio(struct ext4_io_submit *io, 


static void io_submit_add_bh(struct ext4_io_submit *io,

			     struct inode *inode,

			     struct page *pagecache_page,

			     struct page *bounce_page,

			     struct folio *folio,

			     struct folio *io_folio,

			     struct buffer_head *bh)

{

	int ret;



	if (io->io_bio && (bh->b_blocknr != io->io_next_block ||

			   !fscrypt_mergeable_bio_bh(io->io_bio, bh))) {

submit_and_retry:
@@ -422,11 +420,9 @@ static void io_submit_add_bh(struct ext4_io_submit *io, 
	}

	if (io->io_bio == NULL)

		io_submit_init_bio(io, bh);

	ret = bio_add_page(io->io_bio, bounce_page ?: pagecache_page,

			   bh->b_size, bh_offset(bh));

	if (ret != bh->b_size)

	if (!bio_add_folio(io->io_bio, io_folio, bh->b_size, bh_offset(bh)))

		goto submit_and_retry;

	wbc_account_cgroup_owner(io->io_wbc, pagecache_page, bh->b_size);

	wbc_account_cgroup_owner(io->io_wbc, &folio->page, bh->b_size);

	io->io_next_block++;

}
@@ -434,8 +430,9 @@ int ext4_bio_write_page(struct ext4_io_submit *io, 
			struct page *page,

			int len)

{

	struct page *bounce_page = NULL;

	struct inode *inode = page->mapping->host;

	struct folio *folio = page_folio(page);

	struct folio *io_folio = folio;

	struct inode *inode = folio->mapping->host;

	unsigned block_start;

	struct buffer_head *bh, *head;

	int ret = 0;
@@ -443,30 +440,30 @@ int ext4_bio_write_page(struct ext4_io_submit *io, 
	struct writeback_control *wbc = io->io_wbc;

	bool keep_towrite = false;



	BUG_ON(!PageLocked(page));

	BUG_ON(PageWriteback(page));

	BUG_ON(!folio_test_locked(folio));

	BUG_ON(folio_test_writeback(folio));



	ClearPageError(page);

	folio_clear_error(folio);



	/*

	 * Comments copied from block_write_full_page:

	 *

	 * The page straddles i_size.  It must be zeroed out on each and every

	 * The folio 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."

	 */

	if (len < PAGE_SIZE)

		zero_user_segment(page, len, PAGE_SIZE);

	if (len < folio_size(folio))

		folio_zero_segment(folio, len, folio_size(folio));

	/*

	 * In the first loop we prepare and mark buffers to submit. We have to

	 * mark all buffers in the page before submitting so that

	 * end_page_writeback() cannot be called from ext4_end_bio() when IO

	 * mark all buffers in the folio before submitting so that

	 * folio_end_writeback() cannot be called from ext4_end_bio() when IO

	 * on the first buffer finishes and we are still working on submitting

	 * the second buffer.

	 */

	bh = head = page_buffers(page);

	bh = head = folio_buffers(folio);

	do {

		block_start = bh_offset(bh);

		if (block_start >= len) {
@@ -481,14 +478,14 @@ int ext4_bio_write_page(struct ext4_io_submit *io, 
				clear_buffer_dirty(bh);

			/*

			 * Keeping dirty some buffer we cannot write? Make sure

			 * to redirty the page and keep TOWRITE tag so that

			 * racing WB_SYNC_ALL writeback does not skip the page.

			 * to redirty the folio and keep TOWRITE tag so that

			 * racing WB_SYNC_ALL writeback does not skip the folio.

			 * This happens e.g. when doing writeout for

			 * transaction commit.

			 */

			if (buffer_dirty(bh)) {

				if (!PageDirty(page))

					redirty_page_for_writepage(wbc, page);

				if (!folio_test_dirty(folio))

					folio_redirty_for_writepage(wbc, folio);

				keep_towrite = true;

			}

			continue;
@@ -500,11 +497,11 @@ int ext4_bio_write_page(struct ext4_io_submit *io, 
		nr_to_submit++;

	} while ((bh = bh->b_this_page) != head);



	/* Nothing to submit? Just unlock the page... */

	/* Nothing to submit? Just unlock the folio... */

	if (!nr_to_submit)

		return 0;



	bh = head = page_buffers(page);

	bh = head = folio_buffers(folio);



	/*

	 * If any blocks are being written to an encrypted file, encrypt them
@@ -516,6 +513,7 @@ int ext4_bio_write_page(struct ext4_io_submit *io, 
	if (fscrypt_inode_uses_fs_layer_crypto(inode) && nr_to_submit) {

		gfp_t gfp_flags = GFP_NOFS;

		unsigned int enc_bytes = round_up(len, i_blocksize(inode));

		struct page *bounce_page;



		/*

		 * Since bounce page allocation uses a mempool, we can only use
@@ -542,7 +540,7 @@ int ext4_bio_write_page(struct ext4_io_submit *io, 
			}



			printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret);

			redirty_page_for_writepage(wbc, page);

			folio_redirty_for_writepage(wbc, folio);

			do {

				if (buffer_async_write(bh)) {

					clear_buffer_async_write(bh);
@@ -553,18 +551,16 @@ int ext4_bio_write_page(struct ext4_io_submit *io, 


			return ret;

		}

		io_folio = page_folio(bounce_page);

	}



	if (keep_towrite)

		set_page_writeback_keepwrite(page);

	else

		set_page_writeback(page);

	__folio_start_writeback(folio, keep_towrite);



	/* Now submit buffers to write */

	do {

		if (!buffer_async_write(bh))

			continue;

		io_submit_add_bh(io, inode, page, bounce_page, bh);

		io_submit_add_bh(io, inode, folio, io_folio, bh);

	} while ((bh = bh->b_this_page) != head);



	return 0;

include/linux/page-flags.h

+0 −5
Original line number Diff line number Diff line
@@ -766,11 +766,6 @@ bool set_page_writeback(struct page *page); 
#define folio_start_writeback_keepwrite(folio)	\

	__folio_start_writeback(folio, true)



static inline void set_page_writeback_keepwrite(struct page *page)

{

	folio_start_writeback_keepwrite(page_folio(page));

}



static inline bool test_set_page_writeback(struct page *page)

{

	return set_page_writeback(page);