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Diffstat (limited to 'fs/ext4/verity.c')
-rw-r--r--fs/ext4/verity.c47
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,