From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 34A263D6469; Thu, 9 Apr 2026 13:14:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775740475; cv=none; b=AZUXdy1PHlQa60QnbxK7jy4lywKciYnsqwl87Dr8ULyxcMnl3CcjhK6J3yhNcdcsHVgvIM4o+HZG3DG2nB8giNREqWjTAIV2A9+qQzke5iZklxy8Bir7yE2cM3FUyBk0cwQ+3qJ1JKr0OwVidVui2mbgkpPJYSH9W/MaKpDsadY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775740475; c=relaxed/simple; bh=828QqygZ+rCpf7T6T6f7PIgnPBQ8F12tnt1TM4pNE9M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uQHplywvK6IrA1B34OVQuMR6dK05xi8w03m3GotQllOq8WLS+WZB9iBJKiAFcDH58edh5g7qoLStGABK5jhhZJU0v5kLtYX88+Zd/5c+R3s+rgob+/HLBwuSTl4rlFRMhGtCM7+hJ3DgCqJBF3bJC4AoALTPDHWTzDnmTaCF4QM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZrjIey44; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZrjIey44" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A293C2BCB0; Thu, 9 Apr 2026 13:14:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775740474; bh=828QqygZ+rCpf7T6T6f7PIgnPBQ8F12tnt1TM4pNE9M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZrjIey44NbP3a/0szRu03W+a82OE5hpTdNaspyPviqE5KFOJSXMs7+x2gfipmUwYU RhDXv485Ixg0N4nMuIfda8Wcorrpzq+JfNYtKJljUEodSd6EYIQmCAF7/hUOfRvwiI Jm6i5GswO5UzTUHghQyTQj3LZhHrl6Mup7k9yshFFB04E7oTcazvFbH0VGDcDjD+EO +BsQompVhiaBfM17Vzk6hgZtHo0MMM565Q4UypaSL3Vz2mEJ9geRZftovgqBD7efet 5EYluswG62ZL94310DnKOTWtcwUSAaM2ekP1AvqYxRzza0qIhgIBp0cfBl0GW2o9h6 cF7iW7FgGnzvg== From: Andrey Albershteyn To: linux-xfs@vger.kernel.org, fsverity@lists.linux.dev, linux-fsdevel@vger.kernel.org, ebiggers@kernel.org Cc: Andrey Albershteyn , hch@lst.de, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-btrfs@vger.kernel.org, djwong@kernel.org Subject: [PATCH v7 08/22] iomap: teach iomap to read files with fsverity Date: Thu, 9 Apr 2026 15:13:40 +0200 Message-ID: <20260409131404.1545834-9-aalbersh@kernel.org> X-Mailer: git-send-email 2.51.2 In-Reply-To: <20260409131404.1545834-1-aalbersh@kernel.org> References: <20260409131404.1545834-1-aalbersh@kernel.org> Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Obtain fsverity info for folios with file data and fsverity metadata. Filesystem can pass vi down to ioend and then to fsverity for verification. This is different from other filesystems ext4, f2fs, btrfs supporting fsverity, these filesystems don't need fsverity_info for reading fsverity metadata. While reading merkle tree iomap requires fsverity info to synthesize hashes for zeroed data block. fsverity metadata has two kinds of holes - ones in merkle tree and one after fsverity descriptor. Merkle tree holes are blocks full of hashes of zeroed data blocks. These are not stored on the disk but synthesized on the fly. This saves a bit of space for sparse files. Due to this iomap also need to lookup fsverity_info for folios with fsverity metadata. ->vi has a hash of the zeroed data block which will be used to fill the merkle tree block. The hole past descriptor is interpreted as end of metadata region. As we don't have EOF here we use this hole as an indication that rest of the folio is empty. This patch marks rest of the folio beyond fsverity descriptor as uptodate. For file data, fsverity needs to verify consistency of the whole file against the root hash, hashes of holes are included in the merkle tree. Verify them too. Issue reading of fsverity merkle tree on the fsverity inodes. This way metadata will be available at I/O completion time. Reviewed-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Signed-off-by: Andrey Albershteyn --- fs/iomap/buffered-io.c | 41 +++++++++++++++++++++++++++++++++++++++-- include/linux/iomap.h | 2 ++ 2 files changed, 41 insertions(+), 2 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 38c9592fba43..843314852663 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -9,6 +9,7 @@ #include #include #include +#include #include "internal.h" #include "trace.h" @@ -561,9 +562,27 @@ static int iomap_read_folio_iter(struct iomap_iter *iter, if (plen == 0) return 0; - /* zero post-eof blocks as the page may be mapped */ - if (iomap_block_needs_zeroing(iter, pos)) { + /* + * Handling of fsverity "holes". We hit this for two case: + * 1. No need to go further, the hole after fsverity + * descriptor is the end of the fsverity metadata. + * + * 2. This folio contains merkle tree blocks which need to be + * synthesized. If we already have fsverity info (ctx->vi) + * synthesize these blocks. + */ + if ((iomap->flags & IOMAP_F_FSVERITY) && + iomap->type == IOMAP_HOLE) { + if (ctx->vi) + fsverity_fill_zerohash(folio, poff, plen, + ctx->vi); + iomap_set_range_uptodate(folio, poff, plen); + } else if (iomap_block_needs_zeroing(iter, pos)) { + /* zero post-eof blocks as the page may be mapped */ folio_zero_range(folio, poff, plen); + if (ctx->vi && + !fsverity_verify_blocks(ctx->vi, folio, plen, poff)) + return -EIO; iomap_set_range_uptodate(folio, poff, plen); } else { if (!*bytes_submitted) @@ -614,6 +633,15 @@ void iomap_read_folio(const struct iomap_ops *ops, trace_iomap_readpage(iter.inode, 1); + /* + * Fetch fsverity_info for both data and fsverity metadata, as iomap + * needs zeroed hash for merkle tree block synthesis + */ + ctx->vi = fsverity_get_info(iter.inode); + if (ctx->vi && iter.pos < i_size_read(iter.inode)) + fsverity_readahead(ctx->vi, folio->index, + folio_nr_pages(folio)); + while ((ret = iomap_iter(&iter, ops)) > 0) iter.status = iomap_read_folio_iter(&iter, ctx, &bytes_submitted); @@ -681,6 +709,15 @@ void iomap_readahead(const struct iomap_ops *ops, trace_iomap_readahead(rac->mapping->host, readahead_count(rac)); + /* + * Fetch fsverity_info for both data and fsverity metadata, as iomap + * needs zeroed hash for merkle tree block synthesis + */ + ctx->vi = fsverity_get_info(iter.inode); + if (ctx->vi && iter.pos < i_size_read(iter.inode)) + fsverity_readahead(ctx->vi, readahead_index(rac), + readahead_count(rac)); + while (iomap_iter(&iter, ops) > 0) iter.status = iomap_readahead_iter(&iter, ctx, &cur_bytes_submitted); diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 4506a99d5285..4d9202cae29f 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -435,6 +435,7 @@ struct iomap_ioend { loff_t io_offset; /* offset in the file */ sector_t io_sector; /* start sector of ioend */ void *io_private; /* file system private data */ + struct fsverity_info *io_vi; /* fsverity info */ struct bio io_bio; /* MUST BE LAST! */ }; @@ -509,6 +510,7 @@ struct iomap_read_folio_ctx { struct readahead_control *rac; void *read_ctx; loff_t read_ctx_file_offset; + struct fsverity_info *vi; }; struct iomap_read_ops { -- 2.51.2