On Fri, Jun 07, 2019 at 07:51:18AM +0000, Wang Shilong wrote: > Hi, > > > -- > > 2.21.0 > > Won't this break 'chattr' on files that already have this flag set? > FS_IOC_GETFLAGS will return this flag, so 'chattr' will pass it back to > FS_IOC_SETFLAGS which will return EOPNOTSUPP due to this: > > if (ext4_mask_flags(inode->i_mode, flags) != flags) > return -EOPNOTSUPP; > > >>>> > > You are right for this and we also need take care of this in EXT4_IOC_FSSETXATTR/ > this is a bit strange behavior as chattr read existed flags > but could not set them again, there are several possible ways that I could think > of to fix the issue? > > 1) change chattr to filter Project inherit bit before call FS_IOC_SETFLAGS > > 2) we automatically fixed the flag before mask check, something like: > if reg: > flags &= ~PROJECT_INHERT; > if (ext4_mask_flags(inode->i_mode, flags) != flags) > return -EOPNOTSUPP; > But this might be not good.. > > I would prefer solution 1) > What do you think? Existing versions of chattr can't be changed, and people don't necessarily upgrade the kernel and e2fsprogs at the same time. So (1) wouldn't really work. A better solution might be to make FS_IOC_GETFLAGS and FS_IOC_FSGETXATTR never return the project inherit flag on regular files. - Eric
