btrfs: remove btrfs_set_range_writeback()

The function btrfs_set_range_writeback() is originally a callback for
metadata and data, to mark a range with writeback flag.

Then it was converted into a common function call for both metadata and
data.

>From the very beginning, the function is only called on a full page,
later converted to handle range inside a page.

But it never needs to handle multiple pages, and since commit
8189197 ("btrfs: refactor __extent_writepage_io() to do
sector-by-sector submission") the function is only called on a
sector-by-sector basis.

This makes the function unnecessary, and can be converted to a simple
btrfs_folio_set_writeback() call instead.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: adam900710

fs/btrfs/btrfs_inode.h

@@ -577,7 +577,6 @@ void btrfs_merge_delalloc_extent(struct btrfs_inode *inode, struct extent_state
 				 struct extent_state *other);
 void btrfs_split_delalloc_extent(struct btrfs_inode *inode,
 				 struct extent_state *orig, u64 split);
-void btrfs_set_range_writeback(struct btrfs_inode *inode, u64 start, u64 end);
 void btrfs_evict_inode(struct inode *inode);
 struct inode *btrfs_alloc_inode(struct super_block *sb);
 void btrfs_destroy_inode(struct inode *inode);

fs/btrfs/extent_io.c

@@ -1359,7 +1359,7 @@ static int submit_one_sector(struct btrfs_inode *inode,
 	 * a folio for a range already written to disk.
 	 */
 	btrfs_folio_clear_dirty(fs_info, folio, filepos, sectorsize);
-	btrfs_set_range_writeback(inode, filepos, filepos + sectorsize - 1);
+	btrfs_folio_set_writeback(fs_info, folio, filepos, sectorsize);
 	/*
 	 * Above call should set the whole folio with writeback flag, even
 	 * just for a single subpage sector.

fs/btrfs/inode.c

@@ -8963,28 +8963,6 @@ static int btrfs_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
 	return finish_open_simple(file, ret);
 }
 
-void btrfs_set_range_writeback(struct btrfs_inode *inode, u64 start, u64 end)
-{
-	struct btrfs_fs_info *fs_info = inode->root->fs_info;
-	unsigned long index = start >> PAGE_SHIFT;
-	unsigned long end_index = end >> PAGE_SHIFT;
-	struct folio *folio;
-	u32 len;
-
-	ASSERT(end + 1 - start <= U32_MAX);
-	len = end + 1 - start;
-	while (index <= end_index) {
-		folio = __filemap_get_folio(inode->vfs_inode.i_mapping, index, 0, 0);
-		ASSERT(!IS_ERR(folio)); /* folios should be in the extent_io_tree */
-
-		/* This is for data, which doesn't yet support larger folio. */
-		ASSERT(folio_order(folio) == 0);
-		btrfs_folio_set_writeback(fs_info, folio, start, len);
-		folio_put(folio);
-		index++;
-	}
-}
-
 int btrfs_encoded_io_compression_from_extent(struct btrfs_fs_info *fs_info,
 					     int compress_type)
 {