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 <ebiggers@xxxxxxxxxx>
> > #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
