On Tue, Nov 16, 2010 at 10:06:40PM -0500, Ted Ts'o wrote: > > >There is no simple way to test if a filesystem supports hole punching or not so > > >the check has to be done per fs. Thanks, > > > > Could put a flag word in superblock_operations. Filesystems which > > support punching (or other features) can enable it there. > > No, it couldn't be in super_operations. It may vary on a per-inode > basis for some file systems, such as ext4 (depending on whether the > inode is extent-mapped or indirect-block mapped). > > So at least for ext4 we'd need to call into fallocate() function > anyway, once we add support. I suppose if other file systems really > want it, we could add a flag to the super block ops structure, so they > don't have do the "do we support the punch" operation. I can go > either way on that; although if we think the majority of file systems > are going support punch in the long-term, then it might not be worth > it to add such a flag. > Yeah thats alot of extra code just for one part of fallocate. Calling into ->fallocate is perfectly reasonable, especially since ext4 works the way it does, I'm going to leave things as they are. Thanks, Josef -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
