Commit 2c684234 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Linus Torvalds
Browse files

mm: add page_cache_readahead_unbounded 



ext4 and f2fs have duplicated the guts of the readahead code so they can
read past i_size.  Instead, separate out the guts of the readahead code
so they can call it directly.

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Tested-by: default avatarEric Biggers <ebiggers@google.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarWilliam Kucharski <william.kucharski@oracle.com>
Reviewed-by: default avatarEric Biggers <ebiggers@google.com>
Cc: Chao Yu <yuchao0@huawei.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Gao Xiang <gaoxiang25@huawei.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Link: http://lkml.kernel.org/r/20200414150233.24495-14-willy@infradead.org


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b0f31d78

fs/ext4/verity.c

+2 −33
Original line number Diff line number Diff line
@@ -342,37 +342,6 @@ static int ext4_get_verity_descriptor(struct inode *inode, void *buf, 
	return desc_size;

}



/*

 * Prefetch some pages from the file's Merkle tree.

 *

 * This is basically a stripped-down version of __do_page_cache_readahead()

 * which works on pages past i_size.

 */

static void ext4_merkle_tree_readahead(struct address_space *mapping,

				       pgoff_t start_index, unsigned long count)

{

	LIST_HEAD(pages);

	unsigned int nr_pages = 0;

	struct page *page;

	pgoff_t index;

	struct blk_plug plug;



	for (index = start_index; index < start_index + count; index++) {

		page = xa_load(&mapping->i_pages, index);

		if (!page || xa_is_value(page)) {

			page = __page_cache_alloc(readahead_gfp_mask(mapping));

			if (!page)

				break;

			page->index = index;

			list_add(&page->lru, &pages);

			nr_pages++;

		}

	}

	blk_start_plug(&plug);

	ext4_mpage_readpages(mapping, &pages, NULL, nr_pages, true);

	blk_finish_plug(&plug);

}



static struct page *ext4_read_merkle_tree_page(struct inode *inode,

					       pgoff_t index,

					       unsigned long num_ra_pages)
@@ -386,8 +355,8 @@ static struct page *ext4_read_merkle_tree_page(struct inode *inode, 
		if (page)

			put_page(page);

		else if (num_ra_pages > 1)

			ext4_merkle_tree_readahead(inode->i_mapping, index,

						   num_ra_pages);

			page_cache_readahead_unbounded(inode->i_mapping, NULL,

					index, num_ra_pages, 0);

		page = read_mapping_page(inode->i_mapping, index, NULL);

	}

	return page;

fs/f2fs/data.c

+1 −1
Original line number Diff line number Diff line
@@ -2177,7 +2177,7 @@ out: 
 * use ->readpage() or do the necessary surgery to decouple ->readpages()

 * from read-ahead.

 */

int f2fs_mpage_readpages(struct address_space *mapping,

static int f2fs_mpage_readpages(struct address_space *mapping,

			struct list_head *pages, struct page *page,

			unsigned nr_pages, bool is_readahead)

{

fs/f2fs/f2fs.h

+0 −3
Original line number Diff line number Diff line
@@ -3373,9 +3373,6 @@ int f2fs_reserve_new_block(struct dnode_of_data *dn); 
int f2fs_get_block(struct dnode_of_data *dn, pgoff_t index);

int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *from);

int f2fs_reserve_block(struct dnode_of_data *dn, pgoff_t index);

int f2fs_mpage_readpages(struct address_space *mapping,

			struct list_head *pages, struct page *page,

			unsigned nr_pages, bool is_readahead);

struct page *f2fs_get_read_data_page(struct inode *inode, pgoff_t index,

			int op_flags, bool for_write);

struct page *f2fs_find_data_page(struct inode *inode, pgoff_t index);

fs/f2fs/verity.c

+2 −33
Original line number Diff line number Diff line
@@ -222,37 +222,6 @@ static int f2fs_get_verity_descriptor(struct inode *inode, void *buf, 
	return size;

}



/*

 * Prefetch some pages from the file's Merkle tree.

 *

 * This is basically a stripped-down version of __do_page_cache_readahead()

 * which works on pages past i_size.

 */

static void f2fs_merkle_tree_readahead(struct address_space *mapping,

				       pgoff_t start_index, unsigned long count)

{

	LIST_HEAD(pages);

	unsigned int nr_pages = 0;

	struct page *page;

	pgoff_t index;

	struct blk_plug plug;



	for (index = start_index; index < start_index + count; index++) {

		page = xa_load(&mapping->i_pages, index);

		if (!page || xa_is_value(page)) {

			page = __page_cache_alloc(readahead_gfp_mask(mapping));

			if (!page)

				break;

			page->index = index;

			list_add(&page->lru, &pages);

			nr_pages++;

		}

	}

	blk_start_plug(&plug);

	f2fs_mpage_readpages(mapping, &pages, NULL, nr_pages, true);

	blk_finish_plug(&plug);

}



static struct page *f2fs_read_merkle_tree_page(struct inode *inode,

					       pgoff_t index,

					       unsigned long num_ra_pages)
@@ -266,8 +235,8 @@ static struct page *f2fs_read_merkle_tree_page(struct inode *inode, 
		if (page)

			put_page(page);

		else if (num_ra_pages > 1)

			f2fs_merkle_tree_readahead(inode->i_mapping, index,

						   num_ra_pages);

			page_cache_readahead_unbounded(inode->i_mapping, NULL,

					index, num_ra_pages, 0);

		page = read_mapping_page(inode->i_mapping, index, NULL);

	}

	return page;

include/linux/pagemap.h

+3 −0
Original line number Diff line number Diff line
@@ -625,6 +625,9 @@ void page_cache_sync_readahead(struct address_space *, struct file_ra_state *, 
void page_cache_async_readahead(struct address_space *, struct file_ra_state *,

		struct file *, struct page *, pgoff_t index,

		unsigned long req_count);

void page_cache_readahead_unbounded(struct address_space *, struct file *,

		pgoff_t index, unsigned long nr_to_read,

		unsigned long lookahead_count);



/*

 * Like add_to_page_cache_locked, but used to add newly allocated pages:

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