Re: [f2fs-dev] [PATCH] f2fs: prevent compressed file from being disabled after releasing cblocks

[Chao Yu]

On 2020/8/31 11:55, Daeho Jeong wrote:
> > - open(O_RDWR)
> > - ioctl(FS_IOC_SETFLAGS, F2FS_COMPR_FL)
> > - write()
> > - ioctl(RELEASE_COMPRESS_BLOCKS) -- inode is immutable now
> > - ioctl(FS_IOC_SETFLAGS, ~F2FS_COMPR_FL) -- Should we allow to update immutable inode?
> > as we know, normally, immutable inode should deny open(O_WRONLY or O_RDWR) and later update.
>
> For this case, with this patch we'll return -EINVAL for
> ioctl(FS_IOC_SETFLAGS, ~F2FS_COMPR_FL).
> I thought RESERVE_COMPRESS_BLOCKS ioctl is always required to get the
> file to normal mode after RELEASE_COMPRESS_BLOCKS is called.

That's an example, after compressed block release, shouldn't we disallow other ioctl
interface which updates immutable inode?

> .