Merge branch 'for-5.7/appleir' into for-linus

- small code cleanups in hid-appleir from Lucas Tanure

1 files changed, 45 insertions, 2 deletions

diff --git a/fs/ext4/verity.c b/fs/ext4/verity.c
index d0d8a9795dd6..dc5ec724d889 100644
--- a/fs/ext4/verity.c
+++ b/fs/ext4/verity.c
@@ -342,12 +342,55 @@ 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)
+					       pgoff_t index,
+					       unsigned long num_ra_pages)
 {
+	struct page *page;
+
 	index += ext4_verity_metadata_pos(inode) >> PAGE_SHIFT;
 
-	return read_mapping_page(inode->i_mapping, index, NULL);
+	page = find_get_page_flags(inode->i_mapping, index, FGP_ACCESSED);
+	if (!page || !PageUptodate(page)) {
+		if (page)
+			put_page(page);
+		else if (num_ra_pages > 1)
+			ext4_merkle_tree_readahead(inode->i_mapping, index,
+						   num_ra_pages);
+		page = read_mapping_page(inode->i_mapping, index, NULL);
+	}
+	return page;
 }
 
 static int ext4_write_merkle_tree_block(struct inode *inode, const void *buf,