From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C568AC43464 for ; Fri, 18 Sep 2020 13:41:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 68240206DB for ; Fri, 18 Sep 2020 13:41:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="CgGBx4jV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726619AbgIRNlj (ORCPT ); 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200918133439.23187-2-nborisov@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 18.09.20 г. 16:34 ч., Nikolay Borisov wrote: > Instead of relying on indirect calls to implement metadata buffer > validation simply check if the inode whose page we are processing equals > the btree inode. If it does call the necessary function. > > This is an improvement in 2 directions: > 1. We aren't paying the penalty of indirect calls in a post-speculation > attacks world. > > 2. The function is now named more explicitly so it's obvious what's > going on > > This is in preparation to removing struct extent_io_ops altogether. > > Signed-off-by: Nikolay Borisov > --- So this patch does a bit more than it states because it's also modifying the readpage_end_io_hook for data nodes as well. Other than that the code is correct. I'd reword the changelog to the following: Subject: Call readpage_end_io_hook directly " Instead of relying on indirect calls to implement post-read processing simply distinguish between data/metadata pages and call the corresponding function. This patch also renames and exports the 2 hooks giving them more clear names. This is an improvement in 2 directions: 1. We aren't paying the penalty of indirect calls in a post-speculation attacks world. 2. The function is now named more explicitly so it's obvious what's going on This is in preparation to removing struct extent_io_ops altogether. " > fs/btrfs/ctree.h | 2 ++ > fs/btrfs/disk-io.c | 8 ++++---- > fs/btrfs/disk-io.h | 4 +++- > fs/btrfs/extent_io.c | 9 ++++++--- > fs/btrfs/inode.c | 7 +++---- > 5 files changed, 18 insertions(+), 12 deletions(-) > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > index 4e667b0565e0..0c58d96b9fb3 100644 > --- a/fs/btrfs/ctree.h > +++ b/fs/btrfs/ctree.h > @@ -2962,6 +2962,8 @@ void btrfs_inode_safe_disk_i_size_write(struct btrfs_inode *inode, > u64 btrfs_file_extent_end(const struct btrfs_path *path); > > /* inode.c */ > +int btrfs_check_csum(struct btrfs_io_bio *io_bio, u64 phy_offset, > + struct page *page, u64 start, u64 end, int mirror); > struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode, > u64 start, u64 len); > noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len, > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index 160b485d2cc0..5ad11c38230f 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -524,9 +524,9 @@ static int check_tree_block_fsid(struct extent_buffer *eb) > return 1; > } > > -static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio, > - u64 phy_offset, struct page *page, > - u64 start, u64 end, int mirror) > +int btrfs_validate_metadata_buffer(struct btrfs_io_bio *io_bio, u64 phy_offset, > + struct page *page, u64 start, u64 end, > + int mirror) > { > u64 found_start; > int found_level; > @@ -4639,5 +4639,5 @@ static int btrfs_cleanup_transaction(struct btrfs_fs_info *fs_info) > static const struct extent_io_ops btree_extent_io_ops = { > /* mandatory callbacks */ > .submit_bio_hook = btree_submit_bio_hook, > - .readpage_end_io_hook = btree_readpage_end_io_hook, > + .readpage_end_io_hook = NULL > }; > diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h > index 89b6a709a184..bc2e49246199 100644 > --- a/fs/btrfs/disk-io.h > +++ b/fs/btrfs/disk-io.h > @@ -76,7 +76,9 @@ void btrfs_btree_balance_dirty(struct btrfs_fs_info *fs_info); > void btrfs_btree_balance_dirty_nodelay(struct btrfs_fs_info *fs_info); > void btrfs_drop_and_free_fs_root(struct btrfs_fs_info *fs_info, > struct btrfs_root *root); > - > +int btrfs_validate_metadata_buffer(struct btrfs_io_bio *io_bio, u64 phy_offset, > + struct page *page, u64 start, u64 end, > + int mirror); > #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS > struct btrfs_root *btrfs_alloc_dummy_root(struct btrfs_fs_info *fs_info); > #endif > diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c > index afac70ef0cc5..5e47606f7786 100644 > --- a/fs/btrfs/extent_io.c > +++ b/fs/btrfs/extent_io.c > @@ -2851,9 +2851,12 @@ static void end_bio_extent_readpage(struct bio *bio) > > mirror = io_bio->mirror_num; > if (likely(uptodate)) { > - ret = tree->ops->readpage_end_io_hook(io_bio, offset, > - page, start, end, > - mirror); > + if (data_inode) > + ret = btrfs_check_csum(io_bio, offset, page, > + start, end, mirror); > + else > + ret = btrfs_validate_metadata_buffer(io_bio, > + offset, page, start, end, mirror); > if (ret) > uptodate = 0; > else > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index cb3fdd0798c6..23ac09aa813e 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -2817,9 +2817,8 @@ static int check_data_csum(struct inode *inode, struct btrfs_io_bio *io_bio, > * if there's a match, we allow the bio to finish. If not, the code in > * extent_io.c will try to find good copies for us. > */ > -static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio, > - u64 phy_offset, struct page *page, > - u64 start, u64 end, int mirror) > +int btrfs_check_csum(struct btrfs_io_bio *io_bio, u64 phy_offset, > + struct page *page, u64 start, u64 end, int mirror) > { > size_t offset = start - page_offset(page); > struct inode *inode = page->mapping->host; > @@ -10249,7 +10248,7 @@ static const struct file_operations btrfs_dir_file_operations = { > static const struct extent_io_ops btrfs_extent_io_ops = { > /* mandatory callbacks */ > .submit_bio_hook = btrfs_submit_bio_hook, > - .readpage_end_io_hook = btrfs_readpage_end_io_hook, > + .readpage_end_io_hook = NULL > }; > > /* >