[PATCH 00/26] FUSE BPF: A Stacked Filesystem Extension for FUSE

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



These patches extend FUSE to be able to act as a stacked filesystem. This
allows pure passthrough, where the fuse file system simply reflects the lower
filesystem, and also allows optional pre and post filtering in BPF and/or the
userspace daemon as needed. This can dramatically reduce or even eliminate
transitions to and from userspace.

Currently, we either set the backing file/bpf at mount time at the root level,
or at lookup time, via an optional block added at the end of the lookup return
call. The added lookup block contains an fd for the backing file/folder and bpf
if necessary, or a signal to clear or inherit the parent values. We're looking
into two options for extending this to mkdir/mknod/etc, as we currently only
support setting the backing to a pre-existing file, although naturally you can
create new ones. When we're doing a lookup for create, we could pass an
fd for the parent dir and the name of the backing file we're creating. This has
the benefit of avoiding an additional call to userspace, but requires hanging
on to some data in a negative dentry where there is no elegant place to store it.
Another option is adding the same block we added to lookup to the create type
op codes. This keeps that code more uniform, but means userspace must implement
that logic in more areas.

As is, the patches definitely need some work before they're ready. We still
need to go through and ensure we respect changed filter values/disallow changes
that don't make sense. We aren't currently calling mnt_want_write for the lower
calls where appropriate, and we don't have an override_creds layer either. We
also plan to add to our read/write iter filters to allow for more interesting
use cases. There are also probably some node id inconsistencies. For nodes that
will be completely passthrough, we give an id of 0.

For the BPF verification side, we have currently set things set up in the old
style, with a new bpf program type and helper functions. From LPC, my
understanding is that newer bpf additions are done in a new style, so I imagine
much of that will need to be redone as well, but hopefully these patches get
across what our needs there are.

For testing, we've provided the selftest code we have been using. We also have
a mode to run with no userspace daemon in a pure passthrough mode that I have
been running xfstests over to get some coverage on the backing operation code.
I had to modify mounts/unmounts to get that running, along with some other
small touch ups. The most notable failure I currently see there is in
generic/126, which I suspect is likely related to override_creds.


Alessio Balsini (1):
  fs: Generic function to convert iocb to rw flags

Daniel Rosenberg (25):
  bpf: verifier: Allow for multiple packets
  bpf: verifier: Allow single packet invalidation
  fuse-bpf: Update uapi for fuse-bpf
  fuse-bpf: Add BPF supporting functions
  bpf: Export bpf_prog_fops
  fuse-bpf: Prepare for fuse-bpf patch
  fuse: Add fuse-bpf, a stacked fs extension for FUSE
  fuse-bpf: Don't support export_operations
  fuse-bpf: Partially add mapping support
  fuse-bpf: Add lseek support
  fuse-bpf: Add support for fallocate
  fuse-bpf: Support file/dir open/close
  fuse-bpf: Support mknod/unlink/mkdir/rmdir
  fuse-bpf: Add support for read/write iter
  fuse-bpf: support FUSE_READDIR
  fuse-bpf: Add support for sync operations
  fuse-bpf: Add Rename support
  fuse-bpf: Add attr support
  fuse-bpf: Add support for FUSE_COPY_FILE_RANGE
  fuse-bpf: Add xattr support
  fuse-bpf: Add symlink/link support
  fuse-bpf: allow mounting with no userspace daemon
  fuse-bpf: Call bpf for pre/post filters
  fuse-bpf: Add userspace pre/post filters
  fuse-bpf: Add selftests

 fs/fuse/Kconfig                               |   10 +
 fs/fuse/Makefile                              |    1 +
 fs/fuse/backing.c                             | 2753 +++++++++++++++++
 fs/fuse/control.c                             |    2 +-
 fs/fuse/dev.c                                 |   33 +-
 fs/fuse/dir.c                                 |  443 ++-
 fs/fuse/file.c                                |  125 +-
 fs/fuse/fuse_i.h                              |  804 ++++-
 fs/fuse/inode.c                               |  292 +-
 fs/fuse/ioctl.c                               |    2 +-
 fs/fuse/readdir.c                             |   22 +
 fs/fuse/xattr.c                               |   36 +
 fs/overlayfs/file.c                           |   23 +-
 include/linux/bpf.h                           |    4 +
 include/linux/bpf_fuse.h                      |   64 +
 include/linux/bpf_types.h                     |    4 +
 include/linux/bpf_verifier.h                  |    5 +-
 include/linux/fs.h                            |    5 +
 include/uapi/linux/bpf.h                      |   33 +
 include/uapi/linux/fuse.h                     |   19 +-
 kernel/bpf/Makefile                           |    4 +
 kernel/bpf/bpf_fuse.c                         |  342 ++
 kernel/bpf/btf.c                              |    1 +
 kernel/bpf/core.c                             |    5 +
 kernel/bpf/syscall.c                          |    1 +
 kernel/bpf/verifier.c                         |  144 +-
 tools/include/uapi/linux/bpf.h                |   33 +
 tools/include/uapi/linux/fuse.h               | 1066 +++++++
 .../selftests/filesystems/fuse/.gitignore     |    2 +
 .../selftests/filesystems/fuse/Makefile       |   41 +
 .../testing/selftests/filesystems/fuse/OWNERS |    2 +
 .../selftests/filesystems/fuse/bpf_loader.c   |  798 +++++
 .../testing/selftests/filesystems/fuse/fd.txt |   21 +
 .../selftests/filesystems/fuse/fd_bpf.c       |  370 +++
 .../selftests/filesystems/fuse/fuse_daemon.c  |  294 ++
 .../selftests/filesystems/fuse/fuse_test.c    | 2147 +++++++++++++
 .../selftests/filesystems/fuse/test_bpf.c     |  800 +++++
 .../filesystems/fuse/test_framework.h         |  173 ++
 .../selftests/filesystems/fuse/test_fuse.h    |  328 ++
 39 files changed, 11017 insertions(+), 235 deletions(-)
 create mode 100644 fs/fuse/backing.c
 create mode 100644 include/linux/bpf_fuse.h
 create mode 100644 kernel/bpf/bpf_fuse.c
 create mode 100644 tools/include/uapi/linux/fuse.h
 create mode 100644 tools/testing/selftests/filesystems/fuse/.gitignore
 create mode 100644 tools/testing/selftests/filesystems/fuse/Makefile
 create mode 100644 tools/testing/selftests/filesystems/fuse/OWNERS
 create mode 100644 tools/testing/selftests/filesystems/fuse/bpf_loader.c
 create mode 100644 tools/testing/selftests/filesystems/fuse/fd.txt
 create mode 100644 tools/testing/selftests/filesystems/fuse/fd_bpf.c
 create mode 100644 tools/testing/selftests/filesystems/fuse/fuse_daemon.c
 create mode 100644 tools/testing/selftests/filesystems/fuse/fuse_test.c
 create mode 100644 tools/testing/selftests/filesystems/fuse/test_bpf.c
 create mode 100644 tools/testing/selftests/filesystems/fuse/test_framework.h
 create mode 100644 tools/testing/selftests/filesystems/fuse/test_fuse.h


base-commit: bf682942cd26ce9cd5e87f73ae099b383041e782
-- 
2.37.3.998.g577e59143f-goog




[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [NTFS 3]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [NTFS 3]     [Samba]     [Device Mapper]     [CEPH Development]

  Powered by Linux