On 08/27, Chao Yu wrote:
> Hi Eric,
>
> On 2018/8/27 1:35, Eric Biggers wrote:
> > 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
>
> Yeah, but since most copied flags from vfs/ext4 are not actually used in f2fs,
> also 0x00100000 bit is not used now, so we can just define it now directly for
> verity bit.
>
> Cleanup and remapping in ioctl interface for those unused flags, we can do it
> latter?
No, it was reserved by f2fs-tools, and I think this should be aligned to the
encryption bit. Moreover, we guarantee i_flags less strictly from power-cut than
i_advise.
>
> Thanks,
>
> > 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
> >
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