diff options
Diffstat (limited to 'fs/ext4/verity.c')
| -rw-r--r-- | fs/ext4/verity.c | 47 |
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, |