On Mon, 24 Feb 2014, Dave Chinner wrote: > On Sat, Feb 22, 2014 at 09:06:25AM -0500, Theodore Ts'o wrote: > > On Wed, Feb 19, 2014 at 01:37:43AM +0900, Namjae Jeon wrote: > > > + /* > > > + * There is no need to overlap collapse range with EOF, in which case > > > + * it is effectively a truncate operation > > > + */ > > > + if ((mode & FALLOC_FL_COLLAPSE_RANGE) && > > > + (offset + len >= i_size_read(inode))) > > > + return -EINVAL; > > > + > > > > I wonder if we should just translate a collapse range that is > > equivalent to a truncate operation to, in fact, be a truncate > > operation? > > Trying to collapse a range that extends beyond EOF, IMO, is likely > to only happen if the DVR/NLE application is buggy. Hence I think > that telling the application it is doing something that is likely to > be wrong is better than silently truncating the file.... I do agree with Ted on this point. This is not an xfs ioctl added for one DVR/NLE application, it's a mode of a Linux system call. We do not usually reject with an error when one system call happens to ask for something which can already be accomplished another way; nor nanny our callers. It seems natural to me that COLLAPSE_RANGE should support beyond EOF; unless that adds significantly to implementation difficulties? Actually, is it even correct to fail at EOF? What if fallocation with FALLOC_FL_KEEP_SIZE was used earlier, to allocate beyond EOF: shouldn't it be possible to shift that allocation down, along with the EOF, rather than leave it behind as a stranded island? Hugh -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>