From: Goldwyn Rodrigues <rgoldwyn@suse.com>

For buffered reads, call iomap_readahead() and iomap_read_folio().

This is limited to non-subpage calls.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
---
 fs/btrfs/extent_io.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 01408bc5b04e..cfe771cebb36 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1205,9 +1205,15 @@ static int btrfs_do_readpage(struct folio *folio, struct extent_map **em_cached,
 int btrfs_read_folio(struct file *file, struct folio *folio)
 {
 	struct btrfs_bio_ctrl bio_ctrl = { .opf = REQ_OP_READ };
+	struct inode *inode = folio->mapping->host;
+	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 	struct extent_map *em_cached = NULL;
 	int ret;
 
+	if (!btrfs_is_subpage(fs_info, inode->i_mapping))
+		return iomap_read_folio(folio, &btrfs_buffered_read_iomap_ops,
+				&btrfs_iomap_read_folio_ops);
+
 	ret = btrfs_do_readpage(folio, &em_cached, &bio_ctrl, NULL);
 	free_extent_map(em_cached);
 
@@ -2449,10 +2455,17 @@ int btrfs_writepages(struct address_space *mapping, struct writeback_control *wb
 void btrfs_readahead(struct readahead_control *rac)
 {
 	struct btrfs_bio_ctrl bio_ctrl = { .opf = REQ_OP_READ | REQ_RAHEAD };
+	struct inode *inode = rac->mapping->host;
+	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 	struct folio *folio;
 	struct extent_map *em_cached = NULL;
 	u64 prev_em_start = (u64)-1;
 
+	if (!btrfs_is_subpage(fs_info, rac->mapping)) {
+		iomap_readahead(rac, &btrfs_buffered_read_iomap_ops, &btrfs_iomap_read_folio_ops);
+		return;
+	}
+
 	while ((folio = readahead_folio(rac)) != NULL)
 		btrfs_do_readpage(folio, &em_cached, &bio_ctrl, &prev_em_start);
 
-- 
2.46.1