On Thu, Jun 22, 2017 at 01:40:25PM -0600, Andreas Dilger wrote: > > The EXT4_XATTR_MAX_LARGE_EA_SIZE limit of 1MB was also totally arbitrary, > but a reasonable upper limit for the atomic get/set interface used by > xattrs. The underlying disk format could actually store xattrs of any size. > > I'd think if we want to get huge xattrs that they should be handled by > having separate streams (e.g. open file descriptor, ioctl/syscall to select > a different stream number on that file) so that the data doesn't have to be > completely rewritten any time it is modified, but streams are frowned upon > by many Linux developers for security reasons so will probably be a no-go. This has been discussed before. Most of the arguments (both pro and con) can be found on this thread (2016): https://www.spinics.net/lists/linux-nfs/msg57055.html Jeremy Allison used to pester me for alternate data stream support many years ago, but he has since completely changed his opinion on the matter: http://www.spinics.net/lists/linux-fsdevel/msg96083.html So if jra@ doesn't add support for this interface to Samba, the thing I'd ask is who is actually going to used such an interface; because if there aren't any user space applications lining up to use it, it's probably not worth adding it until we can find a flagship user of the proposed new API. There are plenty of other things we could add that Jeremy has asked for, that *would* improve Samba performance. (For example, adding a mount option which provides case-insensitive lookup; the one thing that makes this hard is that while Android doesn't seem to care about I18N --- they are currently using an ascii-only tolower() in their sdcardfs hack --- Samba/Windows does care about I18N done right, so we wouldn't have to get a Unicode case folding implementation into the kernel.) So I'd argue that those are probably more interesting projects than O_XATTR support. - Ted
