Commit c0be8e6f authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Theodore Ts'o
Browse files

ext4: Convert ext4_mpage_readpages() to work on folios 



This definitely doesn't include support for large folios; there
are all kinds of assumptions about the number of buffers attached
to a folio.  But it does remove several calls to compound_head().

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20230324180129.1220691-24-willy@infradead.org


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 0b5a2543

fs/ext4/ext4.h

+1 −1
Original line number Diff line number Diff line
@@ -3646,7 +3646,7 @@ static inline void ext4_set_de_type(struct super_block *sb, 


/* readpages.c */

extern int ext4_mpage_readpages(struct inode *inode,

		struct readahead_control *rac, struct page *page);

		struct readahead_control *rac, struct folio *folio);

extern int __init ext4_init_post_read_processing(void);

extern void ext4_exit_post_read_processing(void);

fs/ext4/inode.c

+3 −4
Original line number Diff line number Diff line
@@ -3154,17 +3154,16 @@ static sector_t ext4_bmap(struct address_space *mapping, sector_t block) 


static int ext4_read_folio(struct file *file, struct folio *folio)

{

	struct page *page = &folio->page;

	int ret = -EAGAIN;

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

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



	trace_ext4_readpage(page);

	trace_ext4_readpage(&folio->page);



	if (ext4_has_inline_data(inode))

		ret = ext4_readpage_inline(inode, folio);



	if (ret == -EAGAIN)

		return ext4_mpage_readpages(inode, NULL, page);

		return ext4_mpage_readpages(inode, NULL, folio);



	return ret;

}

fs/ext4/readpage.c

+28 −30
Original line number Diff line number Diff line
@@ -218,7 +218,7 @@ static inline loff_t ext4_readpage_limit(struct inode *inode) 
}



int ext4_mpage_readpages(struct inode *inode,

		struct readahead_control *rac, struct page *page)

		struct readahead_control *rac, struct folio *folio)

{

	struct bio *bio = NULL;

	sector_t last_block_in_bio = 0;
@@ -247,16 +247,15 @@ int ext4_mpage_readpages(struct inode *inode, 
		int fully_mapped = 1;

		unsigned first_hole = blocks_per_page;



		if (rac) {

			page = readahead_page(rac);

			prefetchw(&page->flags);

		}

		if (rac)

			folio = readahead_folio(rac);

		prefetchw(&folio->flags);



		if (page_has_buffers(page))

		if (folio_buffers(folio))

			goto confused;



		block_in_file = next_block =

			(sector_t)page->index << (PAGE_SHIFT - blkbits);

			(sector_t)folio->index << (PAGE_SHIFT - blkbits);

		last_block = block_in_file + nr_pages * blocks_per_page;

		last_block_in_file = (ext4_readpage_limit(inode) +

				      blocksize - 1) >> blkbits;
@@ -290,7 +289,7 @@ int ext4_mpage_readpages(struct inode *inode, 


		/*

		 * Then do more ext4_map_blocks() calls until we are

		 * done with this page.

		 * done with this folio.

		 */

		while (page_block < blocks_per_page) {

			if (block_in_file < last_block) {
@@ -299,10 +298,10 @@ int ext4_mpage_readpages(struct inode *inode, 


				if (ext4_map_blocks(NULL, inode, &map, 0) < 0) {

				set_error_page:

					SetPageError(page);

					zero_user_segment(page, 0,

							  PAGE_SIZE);

					unlock_page(page);

					folio_set_error(folio);

					folio_zero_segment(folio, 0,

							  folio_size(folio));

					folio_unlock(folio);

					goto next_page;

				}

			}
@@ -333,22 +332,22 @@ int ext4_mpage_readpages(struct inode *inode, 
			}

		}

		if (first_hole != blocks_per_page) {

			zero_user_segment(page, first_hole << blkbits,

					  PAGE_SIZE);

			folio_zero_segment(folio, first_hole << blkbits,

					  folio_size(folio));

			if (first_hole == 0) {

				if (ext4_need_verity(inode, page->index) &&

				    !fsverity_verify_page(page))

				if (ext4_need_verity(inode, folio->index) &&

				    !fsverity_verify_page(&folio->page))

					goto set_error_page;

				SetPageUptodate(page);

				unlock_page(page);

				goto next_page;

				folio_mark_uptodate(folio);

				folio_unlock(folio);

				continue;

			}

		} else if (fully_mapped) {

			SetPageMappedToDisk(page);

			folio_set_mappedtodisk(folio);

		}



		/*

		 * This page will go to BIO.  Do we need to send this

		 * This folio will go to BIO.  Do we need to send this

		 * BIO off first?

		 */

		if (bio && (last_block_in_bio != blocks[0] - 1 ||
@@ -366,7 +365,7 @@ int ext4_mpage_readpages(struct inode *inode, 
					REQ_OP_READ, GFP_KERNEL);

			fscrypt_set_bio_crypt_ctx(bio, inode, next_block,

						  GFP_KERNEL);

			ext4_set_bio_post_read_ctx(bio, inode, page->index);

			ext4_set_bio_post_read_ctx(bio, inode, folio->index);

			bio->bi_iter.bi_sector = blocks[0] << (blkbits - 9);

			bio->bi_end_io = mpage_end_io;

			if (rac)
@@ -374,7 +373,7 @@ int ext4_mpage_readpages(struct inode *inode, 
		}



		length = first_hole << blkbits;

		if (bio_add_page(bio, page, length, 0) < length)

		if (!bio_add_folio(bio, folio, length, 0))

			goto submit_and_realloc;



		if (((map.m_flags & EXT4_MAP_BOUNDARY) &&
@@ -384,19 +383,18 @@ int ext4_mpage_readpages(struct inode *inode, 
			bio = NULL;

		} else

			last_block_in_bio = blocks[blocks_per_page - 1];

		goto next_page;

		continue;

	confused:

		if (bio) {

			submit_bio(bio);

			bio = NULL;

		}

		if (!PageUptodate(page))

			block_read_full_folio(page_folio(page), ext4_get_block);

		if (!folio_test_uptodate(folio))

			block_read_full_folio(folio, ext4_get_block);

		else

			unlock_page(page);

			folio_unlock(folio);

next_page:

		if (rac)

			put_page(page);

		; /* A label shall be followed by a statement until C23 */

	}

	if (bio)

		submit_bio(bio);