Commit d1bd0b4e authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle)
Browse files

fs/buffer: Convert __block_write_begin_int() to take a folio 



There are no plans to convert buffer_head infrastructure to use large
folios, but __block_write_begin_int() is called from iomap, and it's
more convenient and less error-prone if we pass in a folio from iomap.
It also has a nice saving of almost 200 bytes of code from removing
repeated calls to compound_head().

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
parent 640d1930

fs/buffer.c

+12 −11
Original line number Diff line number Diff line
@@ -1969,34 +1969,34 @@ iomap_to_bh(struct inode *inode, sector_t block, struct buffer_head *bh, 
	}

}



int __block_write_begin_int(struct page *page, loff_t pos, unsigned len,

int __block_write_begin_int(struct folio *folio, loff_t pos, unsigned len,

		get_block_t *get_block, const struct iomap *iomap)

{

	unsigned from = pos & (PAGE_SIZE - 1);

	unsigned to = from + len;

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

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

	unsigned block_start, block_end;

	sector_t block;

	int err = 0;

	unsigned blocksize, bbits;

	struct buffer_head *bh, *head, *wait[2], **wait_bh=wait;



	BUG_ON(!PageLocked(page));

	BUG_ON(!folio_test_locked(folio));

	BUG_ON(from > PAGE_SIZE);

	BUG_ON(to > PAGE_SIZE);

	BUG_ON(from > to);



	head = create_page_buffers(page, inode, 0);

	head = create_page_buffers(&folio->page, inode, 0);

	blocksize = head->b_size;

	bbits = block_size_bits(blocksize);



	block = (sector_t)page->index << (PAGE_SHIFT - bbits);

	block = (sector_t)folio->index << (PAGE_SHIFT - bbits);



	for(bh = head, block_start = 0; bh != head || !block_start;

	    block++, block_start=block_end, bh = bh->b_this_page) {

		block_end = block_start + blocksize;

		if (block_end <= from || block_start >= to) {

			if (PageUptodate(page)) {

			if (folio_test_uptodate(folio)) {

				if (!buffer_uptodate(bh))

					set_buffer_uptodate(bh);

			}
@@ -2016,20 +2016,20 @@ int __block_write_begin_int(struct page *page, loff_t pos, unsigned len, 


			if (buffer_new(bh)) {

				clean_bdev_bh_alias(bh);

				if (PageUptodate(page)) {

				if (folio_test_uptodate(folio)) {

					clear_buffer_new(bh);

					set_buffer_uptodate(bh);

					mark_buffer_dirty(bh);

					continue;

				}

				if (block_end > to || block_start < from)

					zero_user_segments(page,

					folio_zero_segments(folio,

						to, block_end,

						block_start, from);

				continue;

			}

		}

		if (PageUptodate(page)) {

		if (folio_test_uptodate(folio)) {

			if (!buffer_uptodate(bh))

				set_buffer_uptodate(bh);

			continue;
@@ -2050,14 +2050,15 @@ int __block_write_begin_int(struct page *page, loff_t pos, unsigned len, 
			err = -EIO;

	}

	if (unlikely(err))

		page_zero_new_buffers(page, from, to);

		page_zero_new_buffers(&folio->page, from, to);

	return err;

}



int __block_write_begin(struct page *page, loff_t pos, unsigned len,

		get_block_t *get_block)

{

	return __block_write_begin_int(page, pos, len, get_block, NULL);

	return __block_write_begin_int(page_folio(page), pos, len, get_block,

				       NULL);

}

EXPORT_SYMBOL(__block_write_begin);

fs/internal.h

+1 −1
Original line number Diff line number Diff line
@@ -37,7 +37,7 @@ static inline int emergency_thaw_bdev(struct super_block *sb) 
/*

 * buffer.c

 */

int __block_write_begin_int(struct page *page, loff_t pos, unsigned len,

int __block_write_begin_int(struct folio *folio, loff_t pos, unsigned len,

		get_block_t *get_block, const struct iomap *iomap);



/*

fs/iomap/buffered-io.c

+5 −2
Original line number Diff line number Diff line
@@ -603,6 +603,7 @@ static int iomap_write_begin(const struct iomap_iter *iter, loff_t pos, 
	const struct iomap_page_ops *page_ops = iter->iomap.page_ops;

	const struct iomap *srcmap = iomap_iter_srcmap(iter);

	struct page *page;

	struct folio *folio;

	int status = 0;



	BUG_ON(pos + len > iter->iomap.offset + iter->iomap.length);
@@ -624,11 +625,12 @@ static int iomap_write_begin(const struct iomap_iter *iter, loff_t pos, 
		status = -ENOMEM;

		goto out_no_page;

	}

	folio = page_folio(page);



	if (srcmap->type == IOMAP_INLINE)

		status = iomap_write_begin_inline(iter, page);

	else if (srcmap->flags & IOMAP_F_BUFFER_HEAD)

		status = __block_write_begin_int(page, pos, len, NULL, srcmap);

		status = __block_write_begin_int(folio, pos, len, NULL, srcmap);

	else

		status = __iomap_write_begin(iter, pos, len, page);
@@ -960,11 +962,12 @@ EXPORT_SYMBOL_GPL(iomap_truncate_page); 
static loff_t iomap_page_mkwrite_iter(struct iomap_iter *iter,

		struct page *page)

{

	struct folio *folio = page_folio(page);

	loff_t length = iomap_length(iter);

	int ret;



	if (iter->iomap.flags & IOMAP_F_BUFFER_HEAD) {

		ret = __block_write_begin_int(page, iter->pos, length, NULL,

		ret = __block_write_begin_int(folio, iter->pos, length, NULL,

					      &iter->iomap);

		if (ret)

			return ret;