From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keith Mok Subject: Re: [PATCH] f2fs: Use crypto crc32 functions Date: Mon, 7 Mar 2016 15:54:24 -0800 Message-ID: References: <1456787577-59946-1-git-send-email-kmok@cyngn.com> <20160302182136.GB9395@jaegeuk.gateway> <20160307233551.GA44902@jaegeuk.gateway> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1ad4yt-0000sa-RX for linux-f2fs-devel@lists.sourceforge.net; Mon, 07 Mar 2016 23:54:31 +0000 Received: from mail-yk0-f179.google.com ([209.85.160.179]) by sog-mx-3.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1ad4yr-0003rl-Uq for linux-f2fs-devel@lists.sourceforge.net; Mon, 07 Mar 2016 23:54:31 +0000 Received: by mail-yk0-f179.google.com with SMTP id 1so55898389ykg.3 for ; Mon, 07 Mar 2016 15:54:29 -0800 (PST) In-Reply-To: <20160307233551.GA44902@jaegeuk.gateway> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: Jaegeuk Kim Cc: Keith Mok , linux-f2fs-devel@lists.sourceforge.net No, other common filesystem use this BUG_ON in this way, pls read: fs/btrfs/hash.c fs/ext4/ext4.h and even the BUG_ON is used inside crc32c function that is exported by libcrc32c.c which xfs and many other drivers are using: lib/libcrc32c.c fs/xfs/libxfs/xfs_cksum.h If it should have some fallback mechanism, it should be done inside the crypto_shash_update function, rather than scatter all over to their users. Thanks. 2016-03-07 15:35 GMT-08:00 Jaegeuk Kim : > On Wed, Mar 02, 2016 at 12:01:02PM -0800, Keith Mok wrote: >> Will update the first BUG_ON by using SHASH_DESC_ON_STACK. > > I meant, for *every* BUG_ONs, doing like: > > if (err) > return original f2fs_crc32(); > > Thanks, > >> >> >> 2016-03-02 10:21 GMT-08:00 Jaegeuk Kim : >> > Hi Keith, >> > >> >> +static inline __u32 f2fs_crc32(struct f2fs_sb_info *sbi, const void *address, >> >> + unsigned int length) >> >> +{ >> >> + struct { >> >> + struct shash_desc shash; >> >> + char ctx[4]; >> >> + } desc; >> >> + int err; >> >> + >> >> + BUG_ON(crypto_shash_descsize(sbi->s_chksum_driver) != sizeof(desc.ctx)); >> > >> > I can't accept this and the below BUG_ON, since this hits during the checkpoint >> > procedure which is very critical for entire filesystem. >> > How about calling back the original method for the error cases? >> > >> > Thanks, >> > >> >> + >> >> + desc.shash.tfm = sbi->s_chksum_driver; >> >> + desc.shash.flags = 0; >> >> + *(u32 *)desc.ctx = F2FS_SUPER_MAGIC; >> >> + >> >> + err = crypto_shash_update(&desc.shash, address, length); >> >> + BUG_ON(err); >> >> + >> >> + return *(__u32 *)desc.ctx; >> >> +} >> >> + >> >> +static inline bool f2fs_crc_valid(struct f2fs_sb_info *sbi, __u32 blk_crc, >> >> + void *buf, size_t buf_size) >> >> +{ >> >> + return f2fs_crc32(sbi, buf, buf_size) == blk_crc; >> >> +} >> >> + >> >> static inline struct f2fs_inode_info *F2FS_I(struct inode *inode) >> >> { >> >> return container_of(inode, struct f2fs_inode_info, vfs_inode); >> >> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c >> >> index 6134832..9630865 100644 >> >> --- a/fs/f2fs/super.c >> >> +++ b/fs/f2fs/super.c >> >> @@ -574,6 +574,8 @@ static void f2fs_put_super(struct super_block *sb) >> >> wait_for_completion(&sbi->s_kobj_unregister); >> >> >> >> sb->s_fs_info = NULL; >> >> + if (sbi->s_chksum_driver) >> >> + crypto_free_shash(sbi->s_chksum_driver); >> >> kfree(sbi->raw_super); >> >> kfree(sbi); >> >> } >> >> @@ -1254,6 +1256,15 @@ try_onemore: >> >> if (!sbi) >> >> return -ENOMEM; >> >> >> >> + /* Load the checksum driver */ >> >> + sbi->s_chksum_driver = crypto_alloc_shash("crc32", 0, 0); >> >> + if (IS_ERR(sbi->s_chksum_driver)) { >> >> + f2fs_msg(sb, KERN_ERR, "Cannot load crc32 driver."); >> >> + err = PTR_ERR(sbi->s_chksum_driver); >> >> + sbi->s_chksum_driver = NULL; >> >> + goto free_sbi; >> >> + } >> >> + >> >> /* set a block size */ >> >> if (unlikely(!sb_set_blocksize(sb, F2FS_BLKSIZE))) { >> >> f2fs_msg(sb, KERN_ERR, "unable to set blocksize"); >> >> @@ -1506,6 +1517,8 @@ free_options: >> >> free_sb_buf: >> >> kfree(raw_super); >> >> free_sbi: >> >> + if (sbi->s_chksum_driver) >> >> + crypto_free_shash(sbi->s_chksum_driver); >> >> kfree(sbi); >> >> >> >> /* give only one another chance */ >> >> -- >> >> 2.5.1 ------------------------------------------------------------------------------ Transform Data into Opportunity. Accelerate data analysis in your applications with Intel Data Analytics Acceleration Library. Click to learn more. http://makebettercode.com/inteldaal-eval