[PATCH 4/4] ext4: readpages() should submit IO as read-ahead

[Jens Axboe <axboe@xxxxxxxxx>]

a_ops->readpages() is only ever used for read-ahead. Ensure that we
pass this information down to the block layer.

Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
 fs/ext4/ext4.h     | 2 +-
 fs/ext4/inode.c    | 5 +++--
 fs/ext4/readpage.c | 5 +++--
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index a42e71203e53..62df0322b567 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3052,7 +3052,7 @@ static inline void ext4_set_de_type(struct super_block *sb,
 /* readpages.c */
 extern int ext4_mpage_readpages(struct address_space *mapping,
 				struct list_head *pages, struct page *page,
-				unsigned nr_pages);
+				unsigned nr_pages, bool is_readahead);
 
 /* symlink.c */
 extern const struct inode_operations ext4_encrypted_symlink_inode_operations;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 1e50c5efae67..2bb50d184bf5 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3327,7 +3327,8 @@ static int ext4_readpage(struct file *file, struct page *page)
 		ret = ext4_readpage_inline(inode, page);
 
 	if (ret == -EAGAIN)
-		return ext4_mpage_readpages(page->mapping, NULL, page, 1);
+		return ext4_mpage_readpages(page->mapping, NULL, page, 1,
+						false);
 
 	return ret;
 }
@@ -3342,7 +3343,7 @@ ext4_readpages(struct file *file, struct address_space *mapping,
 	if (ext4_has_inline_data(inode))
 		return 0;
 
-	return ext4_mpage_readpages(mapping, pages, NULL, nr_pages);
+	return ext4_mpage_readpages(mapping, pages, NULL, nr_pages, true);
 }
 
 static void ext4_invalidatepage(struct page *page, unsigned int offset,
diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
index 9ffa6fad18db..28c857d3b309 100644
--- a/fs/ext4/readpage.c
+++ b/fs/ext4/readpage.c
@@ -98,7 +98,7 @@ static void mpage_end_io(struct bio *bio)
 
 int ext4_mpage_readpages(struct address_space *mapping,
 			 struct list_head *pages, struct page *page,
-			 unsigned nr_pages)
+			 unsigned nr_pages, bool is_readahead)
 {
 	struct bio *bio = NULL;
 	sector_t last_block_in_bio = 0;
@@ -259,7 +259,8 @@ int ext4_mpage_readpages(struct address_space *mapping,
 			bio->bi_iter.bi_sector = blocks[0] << (blkbits - 9);
 			bio->bi_end_io = mpage_end_io;
 			bio->bi_private = ctx;
-			bio_set_op_attrs(bio, REQ_OP_READ, 0);
+			bio_set_op_attrs(bio, REQ_OP_READ,
+						is_readahead ? REQ_RAHEAD : 0);
 		}
 
 		length = first_hole << blkbits;
-- 
2.7.4