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 2CA1C21B908; Tue, 29 Jul 2025 22:07:44 +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=1753826864; cv=none; b=MNfVFWb89+7uzqY6oKkYiyYQgzuMeKzfqdgcczUCarXIWsHT+1nA1E6Row7P7fHy4Bs60XsWFu/UMC59Jxb/E4u8uTTLrWq+Jokv65Dqgzaj6C4AuQ5J4Jf8odU9V7JARORHb7p27p4uuqNS6J9Syou55WShuH79ZY1CzfIzZyc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753826864; c=relaxed/simple; bh=Sfq5QjFkz2SK/zAK/YtWTk1A6MRQh5sud+qPxZdZ2UI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=qVTNgYqYPn4GTqKWuf1xQ5JzOB1fY2vzNyS324HyJtELPWstFrkd2l5LPGzFnVnEaHRWjFBzTlKTQrTTem4Ul8Drg5ddXk0syxLwgwkHW1/ivNYz2U5Q6koTbgTPn9r+rnYoDLPVxhT8Ia3fB5VnWn0jDs5Cc0w0gD6WZpBL8Kc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tiEv0YZD; 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="tiEv0YZD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 01E36C4CEEF; Tue, 29 Jul 2025 22:07:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753826864; bh=Sfq5QjFkz2SK/zAK/YtWTk1A6MRQh5sud+qPxZdZ2UI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=tiEv0YZDlW9mt7pcAEZrIjsReOnlk/q2o2nmkTr+6pj4Tum/Hwh2Z8/qlLqORRpD3 KnFnkONMivW7z0uuWTy/R+iVy6F7A7c2tHEzUgIB7/hY6BE/5VbI/lR5WN5vNwgtWI p4HJfkPEG0THW0p4M8uAQjZ7Z10Kv2Al/2jcrieGR95EH4AAhUGHwkCbhTwcdff5P6 ur68rXT/89u36NUzfE3NTADEjEtoSiZhq8E+Z1W1nltJUsgUmvapM7/rbc62v00nqk V0HniZxZ2Tv4PeVd6NiOwSkLVoDbW/4X1olB0gQUEhmBGkzJ6N49tGGgLgfqK5L3f0 0nz4oj2sDrmQg== Date: Tue, 29 Jul 2025 15:07:43 -0700 From: "Darrick J. Wong" To: Andrey Albershteyn Cc: fsverity@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, david@fromorbit.com, ebiggers@kernel.org, hch@lst.de, Andrey Albershteyn Subject: Re: [PATCH RFC 01/29] iomap: add iomap_writepages_unbound() to write beyond EOF Message-ID: <20250729220743.GI2672049@frogsfrogsfrogs> References: <20250728-fsverity-v1-0-9e5443af0e34@kernel.org> <20250728-fsverity-v1-1-9e5443af0e34@kernel.org> Precedence: bulk X-Mailing-List: fsverity@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250728-fsverity-v1-1-9e5443af0e34@kernel.org> On Mon, Jul 28, 2025 at 10:30:05PM +0200, Andrey Albershteyn wrote: > From: Andrey Albershteyn > > Add iomap_writepages_unbound() without limit in form of EOF. XFS > will use this to write metadata (fs-verity Merkle tree) in range far > beyond EOF. ...and I guess some day fscrypt might use it to encrypt merkle trees too? > Signed-off-by: Andrey Albershteyn > --- > fs/iomap/buffered-io.c | 51 +++++++++++++++++++++++++++++++++++++++----------- > include/linux/iomap.h | 3 +++ > 2 files changed, 43 insertions(+), 11 deletions(-) > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index 3729391a18f3..7bef232254a3 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -1881,18 +1881,10 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, > int error = 0; > u32 rlen; > > - WARN_ON_ONCE(!folio_test_locked(folio)); > - WARN_ON_ONCE(folio_test_dirty(folio)); > - WARN_ON_ONCE(folio_test_writeback(folio)); > - > - trace_iomap_writepage(inode, pos, folio_size(folio)); > - > - if (!iomap_writepage_handle_eof(folio, inode, &end_pos)) { > - folio_unlock(folio); > - return 0; > - } > WARN_ON_ONCE(end_pos <= pos); > > + trace_iomap_writepage(inode, pos, folio_size(folio)); > + > if (i_blocks_per_folio(inode, folio) > 1) { > if (!ifs) { > ifs = ifs_alloc(inode, folio, 0); > @@ -1956,6 +1948,23 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, > return error; > } > > +/* Map pages bound by EOF */ > +static int iomap_writepage_map_eof(struct iomap_writepage_ctx *wpc, iomap_writepage_map_within_eof ? > + struct writeback_control *wbc, struct folio *folio) > +{ > + int error; > + struct inode *inode = folio->mapping->host; > + u64 end_pos = folio_pos(folio) + folio_size(folio); > + > + if (!iomap_writepage_handle_eof(folio, inode, &end_pos)) { > + folio_unlock(folio); > + return 0; > + } > + > + error = iomap_writepage_map(wpc, wbc, folio); > + return error; > +} > + > int > iomap_writepages(struct address_space *mapping, struct writeback_control *wbc, > struct iomap_writepage_ctx *wpc, > @@ -1972,9 +1981,29 @@ iomap_writepages(struct address_space *mapping, struct writeback_control *wbc, > PF_MEMALLOC)) > return -EIO; > > + wpc->ops = ops; > + while ((folio = writeback_iter(mapping, wbc, folio, &error))) { > + WARN_ON_ONCE(!folio_test_locked(folio)); > + WARN_ON_ONCE(folio_test_dirty(folio)); > + WARN_ON_ONCE(folio_test_writeback(folio)); > + > + error = iomap_writepage_map_eof(wpc, wbc, folio); > + } > + return iomap_submit_ioend(wpc, error); > +} > +EXPORT_SYMBOL_GPL(iomap_writepages); > + > +int > +iomap_writepages_unbound(struct address_space *mapping, struct writeback_control *wbc, Might want to leave a comment here explaining what's the difference between the two iomap_writepages exports: /* * Write dirty pages, including any beyond EOF. This is solely for use * by files that allow post-EOF pagecache, which means fsverity. */ > + struct iomap_writepage_ctx *wpc, > + const struct iomap_writeback_ops *ops) > +{ > + struct folio *folio = NULL; > + int error; > + ...and you might want a: WARN_ON(!IS_VERITY(wpc->inode)); to keep it that way. --D > wpc->ops = ops; > while ((folio = writeback_iter(mapping, wbc, folio, &error))) > error = iomap_writepage_map(wpc, wbc, folio); > return iomap_submit_ioend(wpc, error); > } > -EXPORT_SYMBOL_GPL(iomap_writepages); > +EXPORT_SYMBOL_GPL(iomap_writepages_unbound); > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > index 522644d62f30..4a0b5ebb79e9 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -464,6 +464,9 @@ void iomap_sort_ioends(struct list_head *ioend_list); > int iomap_writepages(struct address_space *mapping, > struct writeback_control *wbc, struct iomap_writepage_ctx *wpc, > const struct iomap_writeback_ops *ops); > +int iomap_writepages_unbound(struct address_space *mapping, > + struct writeback_control *wbc, struct iomap_writepage_ctx *wpc, > + const struct iomap_writeback_ops *ops); > > /* > * Flags for direct I/O ->end_io: > > -- > 2.50.0 > >