From: Eric Biggers Subject: Re: [f2fs-dev] [RFC PATCH 10/10] f2fs: fs-verity support Date: Sun, 26 Aug 2018 10:35:08 -0700 Message-ID: <20180826173507.GC728@sol.localdomain> References: <20180824161642.1144-1-ebiggers@kernel.org> <20180824161642.1144-11-ebiggers@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, Dmitry Kasatkin , Michael Halcrow , linux-kernel@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-integrity@vger.kernel.org, Mimi Zohar , Victor Hsieh To: Chao Yu Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Hi Chao, On Sat, Aug 25, 2018 at 01:54:08PM +0800, Chao Yu wrote: > On 2018/8/25 0:16, Eric Biggers wrote: > > From: Eric Biggers > > #ifdef CONFIG_F2FS_CHECK_FS > > #define f2fs_bug_on(sbi, condition) BUG_ON(condition) > > #else > > @@ -146,7 +149,7 @@ struct f2fs_mount_info { > > #define F2FS_FEATURE_QUOTA_INO 0x0080 > > #define F2FS_FEATURE_INODE_CRTIME 0x0100 > > #define F2FS_FEATURE_LOST_FOUND 0x0200 > > -#define F2FS_FEATURE_VERITY 0x0400 /* reserved */ > > +#define F2FS_FEATURE_VERITY 0x0400 > > > > #define F2FS_HAS_FEATURE(sb, mask) \ > > ((F2FS_SB(sb)->raw_super->feature & cpu_to_le32(mask)) != 0) > > @@ -598,7 +601,7 @@ enum { > > #define FADVISE_ENC_NAME_BIT 0x08 > > #define FADVISE_KEEP_SIZE_BIT 0x10 > > #define FADVISE_HOT_BIT 0x20 > > -#define FADVISE_VERITY_BIT 0x40 /* reserved */ > > +#define FADVISE_VERITY_BIT 0x40 > > As I suggested before, how about moving f2fs' verity_bit from i_fadvise to more > generic i_flags field like ext4, so we can a) remaining more bits for those > demands which really need file advise fields. b) using i_flags bits keeping line > with ext4. Not sure, if user want to know whether the file is verity one, it > will be easy for f2fs to export the status through FS_IOC_SETFLAGS. > > #define EXT4_VERITY_FL 0x00100000 /* Verity protected inode */ > > #define F2FS_VERITY_FL 0x00100000 /* Verity protected inode */ > I don't like using i_advise much either, but I actually don't see either location being much better than the other at the moment. The real problem is an artificial one: the i_flags in f2fs's on-disk format are being assumed to use the same numbering scheme as ext4's on-disk format, which makes it seem that they have to be in sync, and that all new ext4 flags (say, EA_INODE) also reserve bits in f2fs and vice versa, when they in fact do not. Instead, f2fs should use its own numbering for its i_flags, and it should map them to/from whatever is needed for common APIs like FS_IOC_{GET,SET}FLAGS and FS_IOC_FS{GET,SET}XATTR. So putting the verity flag in *either* location (i_advise or i_flags) is just kicking the can down the road. If I get around to it I will send a patch that cleans up the f2fs flags properly... Thanks, - Eric