Hi all, When iomap is enabled for a fuse file, we try to keep as much of the file IO path in the kernel as we possibly can. That means no calling out to the fuse server in the IO path when we can avoid it. However, the existing FUSE architecture defers all file attributes to the fuse server -- [cm]time updates, ACL metadata management, set[ug]id removal, and permissions checking thereof, etc. We'd really rather do all these attribute updates in the kernel, and only push them to the fuse server when it's actually necessary (e.g. fsync). Furthermore, the POSIX ACL code has the weird behavior that if the access ACL can be represented entirely by i_mode bits, it will change the mode and delete the ACL, which fuse servers generally don't seem to implement. IOWs, we want consistent and correct (as defined by fstests) behavior of file attributes in iomap mode. Let's make the kernel manage all that and push the results to userspace as needed. This improves performance even further, since it's sort of like writeback_cache mode but more aggressive. If you're going to start using this code, I strongly recommend pulling from my git trees, which are linked below. This has been running on the djcloud for months with no problems. Enjoy! Comments and questions are, as always, welcome. --D kernel git tree: https://git.kernel.org/cgit/linux/kernel/git/djwong/xfs-linux.git/log/?h=fuse-iomap-attrs --- Commits in this patchset: * fuse: force a ctime update after a fileattr_set call when in iomap mode * fuse: synchronize inode->i_flags after fileattr_[gs]et * fuse: cache atime when in iomap mode * fuse: update file mode when updating acls * fuse: propagate default and file acls on creation * fuse: let the kernel handle KILL_SUID/KILL_SGID for iomap filesystems * fuse: update ctime when updating acls on an iomap inode --- fs/fuse/fuse_i.h | 5 ++ fs/fuse/fuse_trace.h | 103 ++++++++++++++++++++++++++++++++++++++++++++++ fs/fuse/acl.c | 104 ++++++++++++++++++++++++++++++++++++++++++++++ fs/fuse/dir.c | 113 ++++++++++++++++++++++++++++++++++++++------------ fs/fuse/inode.c | 20 ++++++++- fs/fuse/ioctl.c | 100 ++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 415 insertions(+), 30 deletions(-)
