btrfs: sink get_extent parameter to read_extent_buffer_pages

All callers pass btree_get_extent, which needs to be exported.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/disk-io.c

@@ -220,7 +220,7 @@ void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb,
  * extents on the btree inode are pretty simple, there's one extent
  * that covers the entire device
  */
-static struct extent_map *btree_get_extent(struct btrfs_inode *inode,
+struct extent_map *btree_get_extent(struct btrfs_inode *inode,
 		struct page *page, size_t pg_offset, u64 start, u64 len,
 		int create)
 {
@@ -455,7 +455,7 @@ static int btree_read_extent_buffer_pages(struct btrfs_fs_info *fs_info,
 	io_tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
 	while (1) {
 		ret = read_extent_buffer_pages(io_tree, eb, WAIT_COMPLETE,
-					       btree_get_extent, mirror_num);
+					       mirror_num);
 		if (!ret) {
 			if (!verify_parent_transid(io_tree, eb,
 						   parent_transid, 0))
@@ -1012,7 +1012,7 @@ void readahead_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr)
 	if (IS_ERR(buf))
 		return;
 	read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
-				 buf, WAIT_NONE, btree_get_extent, 0);
+				 buf, WAIT_NONE, 0);
 	free_extent_buffer(buf);
 }
 
@@ -1031,7 +1031,7 @@ int reada_tree_block_flagged(struct btrfs_fs_info *fs_info, u64 bytenr,
 	set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
 
 	ret = read_extent_buffer_pages(io_tree, buf, WAIT_PAGE_LOCK,
-				       btree_get_extent, mirror_num);
+				       mirror_num);
 	if (ret) {
 		free_extent_buffer(buf);
 		return ret;

fs/btrfs/disk-io.h

@@ -149,6 +149,9 @@ struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
 				     u64 objectid);
 int btree_lock_page_hook(struct page *page, void *data,
 				void (*flush_fn)(void *));
+struct extent_map *btree_get_extent(struct btrfs_inode *inode,
+		struct page *page, size_t pg_offset, u64 start, u64 len,
+		int create);
 int btrfs_get_num_tolerated_disk_barrier_failures(u64 flags);
 int __init btrfs_end_io_wq_init(void);
 void btrfs_end_io_wq_exit(void);

fs/btrfs/extent_io.c

@@ -21,6 +21,7 @@
 #include "locking.h"
 #include "rcu-string.h"
 #include "backref.h"
+#include "disk-io.h"
 
 static struct kmem_cache *extent_state_cache;
 static struct kmem_cache *extent_buffer_cache;
@@ -5248,8 +5249,7 @@ int extent_buffer_uptodate(struct extent_buffer *eb)
 }
 
 int read_extent_buffer_pages(struct extent_io_tree *tree,
-			     struct extent_buffer *eb, int wait,
-			     get_extent_t *get_extent, int mirror_num)
+			     struct extent_buffer *eb, int wait, int mirror_num)
 {
 	unsigned long i;
 	struct page *page;
@@ -5309,7 +5309,7 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
 
 			ClearPageError(page);
 			err = __extent_read_full_page(tree, page,
-						      get_extent, &bio,
+						      btree_get_extent, &bio,
 						      mirror_num, &bio_flags,
 						      REQ_META);
 			if (err) {

fs/btrfs/extent_io.h

@@ -435,7 +435,7 @@ void free_extent_buffer_stale(struct extent_buffer *eb);
 #define WAIT_PAGE_LOCK	2
 int read_extent_buffer_pages(struct extent_io_tree *tree,
 			     struct extent_buffer *eb, int wait,
-			     get_extent_t *get_extent, int mirror_num);
+			     int mirror_num);
 void wait_on_extent_buffer_writeback(struct extent_buffer *eb);
 
 static inline unsigned long num_extent_pages(u64 start, u64 len)