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 945932F29; Mon, 1 Jul 2024 23:40:01 +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=1719877201; cv=none; b=j+ayWlZEuuH3RT0T0tEby3uhqgIVxfUhZ2ZqOLzavJhgiE93+hPbWEvanNRWD388wtAg0SRn4dTiPhrDrcpejHRDJNt7M8emEi7Z/hzmCJAd6zP3UNajGmrOifq7pDZa22ez9FtrtpI3wi9TUHLUqrrRwEydvGC2a0UxZtuRNfo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719877201; c=relaxed/simple; bh=DJGmP0BciHPC13P5upcN22pnyEHNrIh51O+wiRxUohA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kshTJNEvMJf2TR2qBGspNHKQEv4Egqg7eXs4NUtmHGtZFqy+FTa9hGNc/Tn5mBkmzUAHzmkCnT+mb94rMZ880igBSeVYq3irZzD/NR5DjXZk4ERvlX+PTNa5070QGGTbcGYMWZDthlwWiueVJ9zJ54CoyH16xXhS+R2JPw9yDjM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NdC8+mIJ; 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="NdC8+mIJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 218A0C116B1; Mon, 1 Jul 2024 23:40:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1719877201; bh=DJGmP0BciHPC13P5upcN22pnyEHNrIh51O+wiRxUohA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=NdC8+mIJt7i0z7gm3/JuQGXIhy0tuZxP/LtRnNCXV95Uft45WQR4yjbKPZL3r8z+I 8pu71TSyHLkGSyZU90MvaHWL4IAwmhG8CRQ3wjEAvx9z4k4md4JCQUgpjUWLDK7uPL znIZsnYybBFQeG27brhe10v3sGu0budiVQbRH7NpVoUFLpKDCKJbcvy3kY9b4dy7CP Wp/4CX3Ox0dKBVn7OhkX3uZspklBZRu+InmZ1SMMZ+nvbtbZ4OjDGuIJSiv79FzqiW qHolxm4QffMJ8gMC0wjnPNfs5ZlfUy/WfEEW0SeO0ruAdyatlu7mTevvdNh16bhzZi F9ErAozJfncxg== Date: Mon, 1 Jul 2024 16:40:00 -0700 From: "Darrick J. Wong" To: "Pankaj Raghav (Samsung)" Cc: david@fromorbit.com, willy@infradead.org, chandan.babu@oracle.com, brauner@kernel.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, yang@os.amperecomputing.com, linux-mm@kvack.org, john.g.garry@oracle.com, linux-fsdevel@vger.kernel.org, hare@suse.de, p.raghav@samsung.com, mcgrof@kernel.org, gost.dev@samsung.com, cl@os.amperecomputing.com, linux-xfs@vger.kernel.org, hch@lst.de, Zi Yan Subject: Re: [PATCH v8 06/10] iomap: fix iomap_dio_zero() for fs bs > system page size Message-ID: <20240701234000.GH612460@frogsfrogsfrogs> References: <20240625114420.719014-1-kernel@pankajraghav.com> <20240625114420.719014-7-kernel@pankajraghav.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240625114420.719014-7-kernel@pankajraghav.com> On Tue, Jun 25, 2024 at 11:44:16AM +0000, Pankaj Raghav (Samsung) wrote: > From: Pankaj Raghav > > iomap_dio_zero() will pad a fs block with zeroes if the direct IO size > < fs block size. iomap_dio_zero() has an implicit assumption that fs block > size < page_size. This is true for most filesystems at the moment. > > If the block size > page size, this will send the contents of the page > next to zero page(as len > PAGE_SIZE) to the underlying block device, > causing FS corruption. > > iomap is a generic infrastructure and it should not make any assumptions > about the fs block size and the page size of the system. > > Signed-off-by: Pankaj Raghav > Reviewed-by: Hannes Reinecke Looks good to me, Reviewed-by: Darrick J. Wong --D > --- > fs/iomap/buffered-io.c | 4 ++-- > fs/iomap/direct-io.c | 30 ++++++++++++++++++++++++++++-- > 2 files changed, 30 insertions(+), 4 deletions(-) > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index f420c53d86ac..9a9e94c7ed1d 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -2007,10 +2007,10 @@ iomap_writepages(struct address_space *mapping, struct writeback_control *wbc, > } > EXPORT_SYMBOL_GPL(iomap_writepages); > > -static int __init iomap_init(void) > +static int __init iomap_pagecache_init(void) > { > return bioset_init(&iomap_ioend_bioset, 4 * (PAGE_SIZE / SECTOR_SIZE), > offsetof(struct iomap_ioend, io_bio), > BIOSET_NEED_BVECS); > } > -fs_initcall(iomap_init); > +fs_initcall(iomap_pagecache_init); > diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c > index f3b43d223a46..61d09d2364f7 100644 > --- a/fs/iomap/direct-io.c > +++ b/fs/iomap/direct-io.c > @@ -11,6 +11,7 @@ > #include > #include > #include > +#include > #include > #include "trace.h" > > @@ -27,6 +28,13 @@ > #define IOMAP_DIO_WRITE (1U << 30) > #define IOMAP_DIO_DIRTY (1U << 31) > > +/* > + * Used for sub block zeroing in iomap_dio_zero() > + */ > +#define ZERO_PAGE_64K_SIZE (65536) > +#define ZERO_PAGE_64K_ORDER (get_order(ZERO_PAGE_64K_SIZE)) > +static struct page *zero_page_64k; > + > struct iomap_dio { > struct kiocb *iocb; > const struct iomap_dio_ops *dops; > @@ -236,9 +244,13 @@ static void iomap_dio_zero(const struct iomap_iter *iter, struct iomap_dio *dio, > loff_t pos, unsigned len) > { > struct inode *inode = file_inode(dio->iocb->ki_filp); > - struct page *page = ZERO_PAGE(0); > struct bio *bio; > > + /* > + * Max block size supported is 64k > + */ > + WARN_ON_ONCE(len > ZERO_PAGE_64K_SIZE); > + > bio = iomap_dio_alloc_bio(iter, dio, 1, REQ_OP_WRITE | REQ_SYNC | REQ_IDLE); > fscrypt_set_bio_crypt_ctx(bio, inode, pos >> inode->i_blkbits, > GFP_KERNEL); > @@ -246,7 +258,7 @@ static void iomap_dio_zero(const struct iomap_iter *iter, struct iomap_dio *dio, > bio->bi_private = dio; > bio->bi_end_io = iomap_dio_bio_end_io; > > - __bio_add_page(bio, page, len, 0); > + __bio_add_page(bio, zero_page_64k, len, 0); > iomap_dio_submit_bio(iter, dio, bio, pos); > } > > @@ -753,3 +765,17 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, > return iomap_dio_complete(dio); > } > EXPORT_SYMBOL_GPL(iomap_dio_rw); > + > +static int __init iomap_dio_init(void) > +{ > + zero_page_64k = alloc_pages(GFP_KERNEL | __GFP_ZERO, > + ZERO_PAGE_64K_ORDER); > + > + if (!zero_page_64k) > + return -ENOMEM; > + > + set_memory_ro((unsigned long)page_address(zero_page_64k), > + 1U << ZERO_PAGE_64K_ORDER); > + return 0; > +} > +fs_initcall(iomap_dio_init); > -- > 2.44.1 > >