Reserve an F2FS feature flag and inode flag for fs-verity. This is an in-development feature that is planned be discussed at LSF/MM 2018 [1]. It will provide file-based integrity and authenticity for read-only files. Most code will be in a filesystem-independent module, with smaller changes needed to individual filesystems that opt-in to supporting the feature. An early prototype supporting F2FS is available [2]. Reserving the F2FS on-disk bits for fs-verity will prevent users of the prototype from conflicting with other new F2FS features.
Note that we're reserving the inode flag in f2fs_inode.i_advise, which isn't really appropriate since it's not a hint or advice. But ->i_advise is already being used to hold the 'encrypt' flag; and F2FS's ->i_flags uses the generic FS_* values, so it seems ->i_flags can't be used for an F2FS-specific flag without additional work to remove the assumption that ->i_flags uses the generic flags namespace. [1] https://marc.info/?l=linux-fsdevel&m=151690752225644 [2] https://git.kernel.org/pub/scm/linux/kernel/git/mhalcrow/linux.git/log/?h=fs-verity-dev Signed-off-by: Eric Biggers <ebigg...@google.com> --- fs/f2fs/f2fs.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index ae69dc358401..96d7809c4541 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -146,6 +146,7 @@ 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_HAS_FEATURE(sb, mask) \ ((F2FS_SB(sb)->raw_super->feature & cpu_to_le32(mask)) != 0) @@ -598,6 +599,7 @@ 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 file_is_cold(inode) is_file(inode, FADVISE_COLD_BIT) #define file_wrong_pino(inode) is_file(inode, FADVISE_LOST_PINO_BIT) -- 2.17.0.rc1.321.gba9d0f2565-goog ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
